CN100425862C - Shock absorber - Google Patents

Abstract

A shock absorber interposed in parallel with a suspension spring between a vehicle wheel and a vehicle body of a vehicle comprises a main piston (2) partitioning a cylinder (1) into a first operating chamber (R1) and a second operating chamber (R2), and connected to a piston rod (8). The first operating chamber (R1) and the second operating chamber (R2) are connected by a laminated leaf valve (V1, V2) under a first flow resistance. A passage (4a) connects one of the pressure chambers (R3A, R3B) partitioned by a free piston (5) and the first operating chamber (R1) under a second flow resistance. A passage (4b) connects the other of the pressure chambers (R3A, R3B) and the second operating chamber (R2) under a third flow resistance. The shock absorber displays stable damping force characteristics as a result of a spring (S) supporting the free piston (5) in a predetermined neutral position.

Description

Vibration damper

Technical field

The present invention relates to a kind of vibration damper that is used for vehicle.

Background technique

Disclosed a kind of vibration damper respectively among the JP2000-356237A1 that JPH07/019642U1 that the US2005/0011712A1 that U. S. Patent trademark office announced in 2 005 years, Japan Patent office announce nineteen ninety-five and Japan Patent office announced in 2000.In these vibration dampers each all comprise cylinder body, with cylinder body be divided into two active chambers main piston, be arranged in the main piston and connect the passage of two active chambers and two pressure chambers separating and be connected with two active chambers respectively by free-piston.

Because the displacement of working oil response free-piston is and mobile between pressure chamber and active chamber, this small size vibration makes these vibration dampers produce less relatively damping force.On the contrary, significantly vibration causes free-piston to move to the end of stroke, so working oil can not move between each active chamber and corresponding pressure chamber.In this case, working oil is passed passage and is directly moved between two active chambers, and this passage passes the main piston setting.In passage, produced bigger damping force as being provided with of resistance elements such as leaf valve.

Therefore, vibration damper improves damping force rapidly when free-piston arrives stroke terminal.The vibration damper of prior art is provided with buffer outstanding on the direction of displacement of free-piston to alleviate the rapid change of damping force.When free-piston has almost arrived end of travel, the wall portion butt of buffer and pressure chamber.Therefore stoped the displacement of free-piston gradually and damping force is improved gradually.

Summary of the invention

Need a kind of vibration damper that is used for vehicle, to prevent waving of when vehicle travels vehicle on detour by produce bigger damping force with respect to the relative low-frequency vibration that is input to vibration damper.On the other hand, need produce little damping force by the relative high frequency vibration that causes with respect to the relief part of being crossed the road surface by vehicle suppresses the vibration transfer of conduct with respect to the car body of the unsprung weight of vehicle suspension system.

The vibration damper of prior art has satisfied above-mentioned requirements basically by the amplitude change damping force of response inputted vibration.But producing the vibration damper of damping force, response amplitude can not deal with the situation that for example need produce big damping force with respect to inputted vibration with little amplitude.

Therefore, the objective of the invention is the frequency of respond vibration and change damping force and make vibration damper be suitable for dealing with the characteristic of above-mentioned vibration.

In addition, in US2005/0011712A1, the neutral position of free-piston is always not corresponding with the neutral position of main piston.Therefore, be difficult to accurately control the moment that the damping force rapid change takes place.Usually, be used for the process of the vibration damper of vehicle, between an active chamber and another active chamber, produce the pressure reduction of several MPas in expansion and compression stroke.In order to utilize the buffer that is installed on the free-piston to suppress the rapid change of damping force, the spring constant of buffer must be set at high value.Therefore, be difficult to design buffer with required durability.

Therefore another object of the present invention provides and a kind ofly reduces manufacture cost and accurately suppress the vibration damper jumpy of damping force by simplified design.

To achieve these goals, the invention provides a kind of and bearing spring side by side between the wheel of vehicle and the vibration damper between the car body.This vibration damper comprises cylinder body, the main piston that cylinder body is divided into first active chamber and second active chamber, first bindiny mechanism that first active chamber and second active chamber are connected under first-class dynamic resistance, two pressure chambers by free-piston separation with predetermined compression area, with second bindiny mechanism that under second flow resistance, is connected in first active chamber and two pressure chambers, with another the 3rd bindiny mechanism that under the 3rd flow resistance, is connected in second active chamber and two pressure chambers, and have predetermined spring constant and free-piston flexibly is supported on the spring of predetermined neutral position, wherein, first-class dynamic resistance, second flow resistance, the 3rd flow resistance, spring constant (K) and compression area (A) are configured to make the damping force of the vibration attenuation of main piston (2) to reduce along with the raising of the vibration frequency of main piston (2), wherein, the reduction feature of damping force is by through two flex point (Fa, Fb) curve is represented.

Details of the present invention and further feature and advantage provide also shown in the drawings in the other parts of specification.

Description of drawings

Fig. 1 is the schematic representation according to vibration damper of the present invention.

Fig. 2 is the figure that flows that is illustrated in working oil in the expansion stroke process of vibration damper.

Fig. 3 illustrates the plotted curve that concerns between the vibration frequency F and transmission gain in the vibration damper.

Fig. 4 is the plotted curve of relation between the frequency transfer function G (j ω) that vibration frequency F in the vibration damper, displacement phase φ and attenuation characteristic are shown.

Fig. 5 is the side view that comprises the broken section of vibration damper.

Fig. 6 is the amplification cross-sectional view of the critical piece of vibration damper.

Fig. 7 and Fig. 6 are similar, but a variation of housing is shown.

Fig. 8 and Fig. 6 are similar, but another variation of housing is shown.

Fig. 9 is the amplification cross-sectional view according to the critical piece of the vibration damper of second embodiment of the invention.

Figure 10 is the figure that flows that illustrates according to vibration damper working oil in the expansion stroke process of third embodiment of the invention.

Figure 11 is the amplification cross-sectional view according to the critical piece of the vibration damper of third embodiment of the invention.

Figure 12 A-12C is the planimetric map that illustrates according to the sectional shape of the throttle orifice of third embodiment of the invention.

Figure 13 and Figure 11 are similar, but a variation of through hole is shown.

Figure 14 and Figure 11 are similar, but a variation of the layout of throttle orifice and annular slot is shown

Figure 15 is the amplification cross-sectional view according to the critical piece of the vibration damper of fourth embodiment of the invention.

Embodiment

Require the embodiments of the present invention of patent rights or privilege to limit as follows.

With reference to the Fig. 1 in the accompanying drawing, the vibration damper that is used for vehicle comprises cylinder body 1, slide in cylinder body 1 and cylinder body 1 is divided into the main piston 2 of two active chambers and protruding and be connected to piston rod 8 on the main piston 2 from cylinder body 1.Two active chambers are designed on main piston is more than 2 active chamber R 1 and at the following active chamber R2 of main piston below 2.

Last active chamber R1 and following active chamber R2 are connected by the first passage 3 that is arranged in the main piston 2.

Cylindrical pressure chamber R3 is arranged in the main piston 2 and free-piston 5 is housed in wherein.Pressure chamber R3 is divided into upward pressure chamber R3A and downforce chamber R3B by free-piston 5.Working oil is filled and is gone up active chamber R1, following active chamber R2, upward pressure chamber R3A and downforce chamber R3B.

By spring S free-piston 5 flexibly is supported on neutral position (neutralposition).

Upward pressure chamber R3A and last active chamber R1 are configured to be communicated with by the second channel 4a that is provided with throttle orifice 11.Downforce chamber R3B and following active chamber R2 are configured to be communicated with by the third channel 4b that is provided with throttle orifice 12.Although owing to the free-piston 5 of divider passages 4a, 4b is not communicated with passage 4a, 4b mutually, in these passages 4a, 4b, flow simultaneously with the working oil of the corresponding equivalent of travelling speed of free-piston 5.

Air cavity G is separated by the free-piston 7 of main piston 2 belows of cylinder body 1.Air cavity G gassy.Therefore, air cavity G can cushion the variation of the displacement volume (displacement volume) of the cylinder body 1 that is caused by entering of piston rod 8.Sealing component between cylinder body 1 and piston rod 8 keeps the oil seal performance of cylinder body 1.

Masterpiece when vertically is used on the piston rod 8 or on the cylinder body 1 or on these two parts the time, piston rod 8 moves with respect to cylinder body 1.This relative displacement causes main piston 2 mobile in cylinder body 1 along Vertical direction as shown in the figure.

The deamplification force generating member 10 that comprises throttle orifice or leaf valve is provided with along first passage 3, with the mobile resistance that applies to working oil.

When vibration damper stood expansion stroke, in other words, when piston rod 8 stretched out from cylinder body 1, main piston 2 compressions were gone up active chamber R1 and active chamber R2 are enlarged.Therefore, the pressure in the last active chamber R1 improves and the interior pressure reduction of active chamber R2 down.

Pressure raising in the last active chamber R1 makes working oil pass second channel 4a and moves to upward pressure chamber R3A.As a result, the elastic force of antagonistic spring S is depressed free-piston 5.The depressing of free-piston 5 makes working oil pass third channel 4b from the downforce chamber R3B that is in compressive state and moves to the following active chamber R2 with lower relative pressure.When vibration damper further expanded, working oil was passed first passage 3 from last active chamber R1 and is flowed to active chamber R2 down.

When vibration damper through by compression the time, in other words, when piston rod 8 entered cylinder body 1, main piston 2 compression active chamber R2 down also made active chamber R1 expansion.Therefore, the pressure in the last active chamber R1 reduces and the interior pressure raising of active chamber R2 down.

The following active chamber R2 that working oil is enhanced from pressure passes third channel 4b and flows to downforce chamber R3B and free-piston 5 is upwards pressed with spring S.The moving up of free-piston 5 makes working oil pass the last active chamber R1 that second channel 4 a move to the pressure with reduction from the upward pressure chamber R3A of volume with compression.When vibration damper stood further to compress, working oil was passed first passage 3 from descending active chamber R1 on the active chamber R2 flow direction.

The volume that piston rod 8 takies in cylinder body 1 is along with the compression of aforesaid vibration damper and expansion and change.Expansion and the compression of the air cavity G of the fluctuation of working oil volume by utilizing free-piston 7 replenish in the caused cylinder body 1 of the variation of the volume that is taken by piston rod 8.

Then, with reference to Fig. 2 the damping force characteristic of vibration damper is described.

Below when main piston 2 moved up, in other words be that working oil mobile of vibration damper when standing expansion stroke considered.

Pressure reduction between last active chamber R1 and the following active chamber R2 is defined as P.

When the flow from the working oil of last active chamber R1 is designated as Q, the flow that passes the working oil of first passage 3 is Q1, and the flow that flows through the working oil of second channel 4a obtains following formula (1) when being Q2.

Q＝Q1+Q2 (1)

Because the flow Q1 of pressure reduction P and first passage 3 obtains the relation by following formula (2) expression.

P＝C1·Q1 (2)

Wherein, C1=flow coefficient.

When the pressure among the R3A of upward pressure chamber is designated as P1, obtain following formula (3).

P＝P1+C2·Q2 (3)

Wherein, C2=flow coefficient.

Instantly the pressure among the pressure chamber R3B is P2, and the compression area of free-piston 5 is A, and the displacement amount of free-piston 5 is X, and the spring constant of spring S obtains following formula (4) when being K.

P1·A＝P2·A+K·X (4)

Working oil is passed the third channel 4b flow direction from downforce chamber R3B and is descended the flow of active chamber R2 to equal the flow Q2 of second channel 4a.Therefore, obtain the formula (5) relevant with the pressure P 2 among the R3B of downforce chamber.

P2＝C3·Q2 (5)

Wherein, C3=flow coefficient.

The amount of movement of working oil is provided by formula (6).

A·X＝∫Q2·dt (6)

When formula (1)-(6) being carried out laplace transformation when calculating pressure reduction P, obtain formula (7) with respect to the transfer function of flow Q.

$G\left(s\right)=\frac{P\left(s\right)}{Q\left(s\right)}=\frac{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1\&CenterDot;\{1+A^2\&CenterDot;(\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)\&CenterDot;\frac{s}{K}\}}{1+A^2\&CenterDot;(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)\&CenterDot;\frac{s}{K}}---\left(7\right)$

Wherein, s=Laplace operator.

By the Laplace operator s in the transfer function of j ω being appointed as formula (7), obtain formula (8) with calculated rate transfer function G (j ω) absolute value.

$\left|G(j\&CenterDot;\mathrm{\&omega;})\right|=\frac{C1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">K</figure-callout>}}^2+A^4\&CenterDot;{(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)}^2\&CenterDot;{\mathrm{\&omega;}}^2}\&CenterDot;$

$[{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="C20061008391900301.png"\; state="\{\{state\}\}">K</figure-callout>}}^4+{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">K</figure-callout>}}^2\&CenterDot;A^4\&CenterDot;\{2\&CenterDot;(\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)\&CenterDot;(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)+{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1}^2\}\&CenterDot;{\mathrm{\&omega;}}^2+$

$A^8\&CenterDot;{(\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)}^2\&CenterDot;{(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)}^2\&CenterDot;{\mathrm{\&omega;}}^4{]}^{\frac{1}{2}}$

The phase of frequency transfer function is provided by formula (9).

$\mathrm{\&phi;}={\mathrm{Tan}}^{-1}\left\{\frac{-\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1\&CenterDot;K\&CenterDot;A^2\&CenterDot;\mathrm{\&omega;}}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">K</figure-callout>}}^2+A^4\&CenterDot;(\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)\&CenterDot;(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)\&CenterDot;{\mathrm{\&omega;}}^2}\right\}$

Frequency F provides by remove angular frequency with 2 π in formula (9).Referring now to Fig. 3, frequency transfer function G (j ω) shows two break frequencies with respect to the gain characteristic of vibration frequency F $\mathrm{Fa}=\frac{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">K</figure-callout>}}{2\&CenterDot;\mathrm{\&pi;}\&CenterDot;A^2\&CenterDot;(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C20061008391900391.png"\; state="\{\{state\}\}">C</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)}$ With $\mathrm{Fb}=\frac{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">K</figure-callout>}}{2\&CenterDot;\mathrm{\&pi;}\&CenterDot;A^2\&CenterDot;(\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061008391900301.png,C20061008391900311.png"\; state="\{\{state\}\}">C</figure-callout>}2+C3)}.$ In the figure, transmission gain is substantially equal to C1 in the zone of F＜Fa.In the zone of Fa≤F≤Fb, transmission gain is reduced to gradually from C1

In the zone of F＞Fb, transmission gain is

Gain characteristic by the frequency transfer function G (j ω) that obtains with upper type is by square multiply by the compression area B of main piston 2 | G (j ω) | be converted to damping coefficient ζ.Under this mode, can obtain the relation between the attenuation characteristic of as shown in Figure 4 frequency F, phase and frequency transfer function G (j ω).

In other words, this vibration damper produces big damping force and produce little damping force when frequency F is higher than break frequency Fb when frequency F is lower than break frequency Fa.Be higher than break frequency Fa and be lower than the zone of break frequency Fb at frequency F, damping force reduces gradually along with the raising of frequency F.

Therefore, can utilize the compression area A of flow coefficient C 1, flow coefficient C 2, flow coefficient C 3, piston 5 and the spring constant K of spring S to determine break frequency Fa and Fb.Utilize formula (2) calculated flow rate coefficient C1, flow coefficient C 1 expression pressure reduction P and pass relation between the flow Q1 of working oil of first passage 3.Utilize formula (3) calculated flow rate coefficient C2, the pressure P 1 among the flow coefficient C 2 expression upward pressure chamber R3A and pass relation between the flow Q2 of working oil of second channel 4a.Utilize formula (5) calculated flow rate coefficient C3, the pressure P 2 among the flow coefficient C 3 expression downforce chamber R3B and pass relation between the flow Q2 of working oil of third channel 4b.

Utilize the compression area B of flow coefficient C 1, C2, C3 and piston 2 to calculate damping coefficient ζ.

If desired, can utilize the spring constant K of the compression area A of flow coefficient C 1, C2, C3, free-piston 5 and spring S to determine the attenuation characteristic of vibration damper.

Flow coefficient C 1 is the value of being determined by the mobile resistance that applies of the 10 pairs of working oil of deamplification force generating member in the first passage 3.Flow coefficient C 2 is values of being determined by the resistance of the mobile generation that is arranged on the 11 pairs of working oil of throttle orifice in the second channel 4a.Flow coefficient C 3 is values of being determined by the resistance of the mobile generation of 12 pairs of working oil of the throttle orifice in the third channel 4b.

Can provide with spring constant K and be set at the basis, regulate simply to the break frequency Fa shown in Fig. 4 and Fb and with respect to the variable quantity of the damping coefficient ζ of inputted vibration frequency F to the compression area A of flow coefficient C1, C2, C3, free-piston 5 and spring S.

In other words, the conventional vibration damper that changes the damping force characteristic with the response amplitude size forms contrast, and this vibration damper can be with respect to inputted vibration frequency shift damping force characteristic.This vibration damper also is convenient to the adjusting of damping force.As a result, can be with respect to producing little damping force through the high frequency inputted vibration that the relief part on road surface causes by vehicle.In addition, low frequency inputted vibration that can the load change on the vibration damper causes with respect to by Vehicular turn the time produces big damping force.

Because this vibration damper is convenient to the adjusting of attenuation characteristic, therefore when on the vehicle of shock absorber application at all size, need not to carry out complicated adjusting and just can produce the damping force characteristic of mating with vehicle.In addition, also be convenient to design and adjustment.

When the break frequency Fb among two break frequency Fa and the Fb is configured to less than vehicle not during the value of the resonant frequency of mounting spring, then when the vibration input vehicle of the resonant frequency of mounting spring not, as shown in Figure 4, vibration damper always produces less damping force.Therefore, these characteristics have been kept best vehicle operation characteristic.

Exceed the zone of break frequency Fb at inputted vibration frequency F, the phase delay of damping coefficient ζ shows the trend that reduces, and does not lingeringly produce damping force with respect to inputted vibration.Therefore, these characteristics have been kept best vehicle operation characteristic.

By less break frequency Fa is set for less than vehicle not mounting spring resonant frequency and guarantee to produce big damping force with respect to inputted vibration greater than the value of the resonant frequency of mounting spring greater than the resonant frequency of mounting spring by vibration damper.When Vehicular turn, these stability of characteristics vehicle direction and kept stability, make the passenger can not feel dangerous.At the frequency field less than break frequency Fa, the phase delay of damping coefficient ζ is tending towards reducing and does not lingeringly produce damping force with respect to inputted vibration.Therefore, these characteristics have also produced the best effort characteristic that the passenger is felt safe.

The setting of flow coefficient C 2 and C3 makes in throttle orifice 11 and 12 any one to be removed.The cross sectional area that can also set passage 4a and 4b satisfies flow coefficient C 2 and C3 under the situation of not using throttle orifice 11 and 12.

Then, the detailed structure with reference to Fig. 5 and 6 pairs of vibration dampers describes.

Fig. 5 shows the general structure of vibration damper.As shown in the drawing, the pressure chamber R3 that accommodates free-piston 5 is arranged in the housing 30, and this housing 30 is combined into one with main piston 2 below main piston 2.Support 60 on the upper end of the piston rod 8 in vibration damper links to each other with car body, and the support 61 on the lower end of cylinder body 1 links to each other with vehicle axles.

With reference to Fig. 6, minor radius section 8a is arranged on the lower end of piston rod 8.Male thread portion 8b is formed on the top of minor radius section 8a.Second channel 4a passes the inboard that minor radius section 8a is formed on piston rod 8.The end of second channel 4a links to each other with last active chamber R1, and the other end is opened from the lower ends downward of piston rod 8.Throttle orifice 11 is along second channel 4a formation and have the inner radial littler than second channel 4a.Replacement is provided with throttle orifice 11 in the position shown in this figure, can assign to form throttle orifice 11 by the cross sectional area of the opening on the top of sealing minor radius section 8a or the joint between second channel 4a and the last active chamber R1.

Piston 2 comprises the annular component with hollow core.The minor radius section 8a of piston rod 8 passes this hollow core.A pair of first passage 3 passes piston 2 and connects goes up active chamber R1 and following active chamber R2.In a upper end of first passage 3, face the opening of active chamber R1 by stacked leaf valve V1 sealing as deamplification force generating member 10.In another lower end of first passage 3, in the face of the opening of active chamber R2 down also by stacked leaf valve V2 sealing as deamplification force generating member 10.

Stacked leaf valve V1 and V2 form ring-type respectively, and engage with the periphery of the minor radius section 8a of piston rod 8 in week in it.Stacked leaf valve V1 and V2 are layered on the piston 2.Stacked leaf valve V1 and the amount of bow of V2 are respectively by annular valve brake component 28 on the periphery that is assemblied in minor radius section 8a and 29 restrictions.

Minor radius section 8a passes brake component 28, stacked leaf valve V1, main piston 2, stacked leaf valve V2 and brake component 29 successively.The female thread portion 31a that is formed on the housing 30 is threaded with the male thread portion 8b that is formed on the top.Thus, brake component 28, stacked leaf valve V1, main piston 3, stacked compressing tablet valve V2 and brake component 29 are fixed to piston rod 8.

In the compression stroke process of vibration damper, stacked leaf valve V1 makes working oil pass the first passage 3 with fixed resistance from following active chamber R2 and flows to upward active chamber R1 by responding down crooked being opened of pressure reduction between active chamber R2 and the last active chamber R1.When vibration damper stood expansion stroke, the first passage 3 of facing stacked leaf valve V1 was closed.

In the expansion stroke process of vibration damper, stacked leaf valve V2 makes working oil pass the first passage 3 with fixed resistance from last active chamber R1 and flows to active chamber R2 down by responding down crooked being opened of pressure reduction between active chamber R2 and the last active chamber R1.When vibration damper stood compression stroke, the first passage 3 of facing stacked leaf valve V2 was closed.In other words, stacked leaf valve V1 produces damping force with respect to the compression stroke of vibration damper, and stacked leaf valve V2 produces damping force with respect to the expansion stroke of vibration damper.

The damping force that stacked leaf valve V1 and V2 produce is configured to bigger than the damping force of passage 4a and 4b generation.

The inner core 31 of the female thread portion 31a that housing 30 comprises cylindrical shape urceolus 33, abut to flange 32 on the brake component 29 from below, formation is threaded with the male thread portion 8b of piston rod 8 and the lid 34 of sealing urceolus 33 lower ends.Inner core 31 is vertically from the inboard that reaches urceolus 33 interior week downwards of flange 32.Inner core 31, flange 32 and urceolus 33 form with integrative-structure.Lid 34 is fixed to the lower end of urceolus 33 by crimp (caulking).

Free-piston 5 is housed in the inboard of housing 30, and the pressure chamber R3 in the housing 30 is divided into upward pressure chamber R3A and downforce chamber R3B by free-piston 5.

The second channel 4a of the lower ending opening of the minor radius section 8a that upward pressure chamber R3A passes through at piston rod 8 is communicated with last active chamber R1.

The sectional shape of the periphery of urceolus 33 is the circles with sunk part.This shape is suitable for utilizing the instrument that engages with this periphery inner core 31 to be fixed to the minor radius section 8a of piston rod 8.Yet, can carry out the sectional shape of periphery of the urceolus 33 of above operation can also right and wrong circle or can be Hexagon for example just.The sectional shape of the periphery of urceolus 33 is chosen to be the fixing operation of being convenient on the piston rod 8 of housing 30.

Lid 34 is to comprise the columnar member with closed end that is provided with flange.The periphery of flange is fixed to the lower end of urceolus 33 by crimp.Connecting the third channel 4b of active chamber R2 and downforce chamber R3B down is formed on and covers on 34 the bottom.Have little value by the cross sectional area that makes third channel 4b, third channel 4b itself plays the effect of throttle orifice 12.

Free-piston 5 is included in the bottom 52 of the lower end of the cylindrical shape part 51 of go up sliding in interior week of urceolus 33 and closed circular tubular part 51.Bottom 52 is included in central prone projection 53.

Wind spring 6 is arranged on the inboard of downforce chamber R3B.Wind spring 6 is between the bottom 52 of lid 34 and free-piston 5.Wind spring 6 is limited by projection 53 and lid 34 along periphery layout and its displacement radially of projection 53.

Wind spring 56 is arranged on the inboard of upward pressure chamber R3A.To free-piston 5 application of forces, and wind spring 56 is between the bottom 52 of flange 32 and free-piston 5 along the direction opposite with spring 6 for wind spring 56.Wind spring 56 along arrange in interior week of cylindrical shape part 51 and its radially the displacement of z by 51 restrictions of cylindrical shape part.

Free-piston 5 is flexibly supported by wind spring 6 and 56 in vertical direction.When the pressure in the pressure chamber R3B equals pressure in the R3A of upward pressure chamber instantly, free-piston 5 is stably remained on fixing neutral position.Wind spring 6 and 56 is corresponding to the spring S among Fig. 1 and 2.

These springs 6 and 56 prevent the relative displacement of central axis of the central axis of free-piston 5 and urceolus 33 and the relative tilt between the two axial lines, and the slip resistance that suppresses free-piston 5 thus improves undesirablely.

The inner radial of the cylindrical shape part 51 of free-piston 5 increases in the upward direction.The increase of this radius has kept the space for the increase of coil radius when wind spring 56 compresses.When the coil radius of wind spring 56 enlarges in compression process, interior all butts of wind spring 56 and cylindrical shape part 51.At this moment, when free-piston 5 was mobile vertically, it was contaminated possible owing to the wearing and tearing between piston 5 and the spring 56 to exist working oil.The inner radial of cylindrical shape part 51 along upward to expansion pollute effectively for the working oil that prevents this form.

Free-piston 5 slides cylindrical shape part 51 on the interior week of urceolus 33.Therefore, can keep enough big axial length to sliding parts.This supporting structure of free-piston 5 is for the relative displacement of the central axis of central axis that prevents free-piston 5 and urceolus 33 and for preventing that the relative tilt between the two axial lines from being preferred.

Referring again to Fig. 5, separate the free-piston 7 of active chamber R2 and air cavity G down and be provided with along upward to the sunk part of opening.During the maximum compression of vibration damper, the lid 34 of housing 30 is contained in this sunk part.Usually, on the top of the piston rod 8 of mono-tube shock absorber housing 30 being set is disadvantageous from the angle that keeps stroke distances.Yet the sunk part that forms above-mentioned form on free-piston 7 makes stroke distances can obtain some prolongation.

The attenuation characteristic of Gou Zao vibration damper is determined by the spring constant K of the compression area A of free-piston 5, aforesaid each flow coefficient C 1, C2, C3 and spring S as mentioned above.The spring constant K of spring represents total spring constant of wind spring 6 and 56.

Flow coefficient C 1 depends on the flow resistance of stacked leaf valve V1 and V2.Flow coefficient C 2 depends on the flow resistance of throttle orifice 11.Flow coefficient C 3 has depended on the flow resistance of the third channel 4b of throttle orifice 12 effects.

Therefore, the setting with the spring constant K of the compression area A of the flow resistance of upper member, free-piston 5 and spring S makes break frequency Fa and Fb to set in any way.Damping coefficient ζ also can set in any way with respect to the variable quantity of inputted vibration frequency F.Therefore, this vibration damper is convenient to respond the attenuation characteristic of inputted vibration frequency and is set arbitrarily.

According to flow coefficient C 3,, just can improve the section area of third channel 4b as long as free-piston 5 does not separate with housing 30 with wind spring 6.Under this mode, can make the flow resistance minimum of working oil.In addition, if second channel 4 a can satisfy the setting of flow coefficient C 2 under the situation that throttle orifice 11 is not set, then can save throttle orifice 11.

In this vibration damper, several attenuation characteristics of using can selected by vehicle driver's manually-operable or according to the command signal of slave controller output can be arranged.

For example, valve seat is arranged on the opening of second channel 4a on top of the minor radius section 8a that is formed on piston rod 8.Can operate from the outside of vibration damper by the controlling rod that passes piston rod 8 settings with the poppet valve of valve seat relativity.Owing to the variation of the flow resistance of working oil in second channel 4a along with the surface area of the opening of the poppet valve of controlled bar control changes, therefore can change flow coefficient C 2 in any way.Replace poppet valve, can adopt spool valve or rotary valve.

Then, with reference to Fig. 7 the variation of housing 30 is described.

This variation is that the urceolus 33 of housing 30 separates with flange 32.Inner core 31 and flange 32 constitute first member 71 of one, and urceolus 33 and lid 34 constitute second member 74 of one.

The flange 32 of first member 71 of one is fixed to the upper end of the urceolus 33 of second member 74 by crimp.

When vibration damper was assembled, the inner core 31 of first member 71 was threaded on the male thread portion 8b on piston rod 8 tops.

Wind spring 6 and 56 and free-piston 5 be arranged in second member 74.Under this state, the flange 32 of first member 71 is fixed to the upper end of the urceolus 33 of second member 74 by crimp.

When constructing housing 30 in the above described manner, inner core 31 is on the male thread portion 8b that need not to be threaded under second member 74 applies the situation of torque on piston rod 8 tops.Therefore, can prevent to be convenient to the assembling of housing 30 owing to the distortion that housing 30 is installed in second member 74 that causes on the piston rod 8.

Even when the distortion of second member 74 very hour, also can produce and not wish the influence that occurs the slip of free-piston 5 in inside.Therefore, when constructing housing 30 in the above described manner, the smooth sliding of free-piston 5 can be guaranteed and designed attenuation characteristic can realize.

With reference to Fig. 8 another variation of housing 30 is described.

In this changed, the urceolus 33 and the flange 32 of housing 30 separated.In vibration damper shown in Figure 6 urceolus 33 and lid 34 also be separately and interfix by crimp.

Sleeve 84 inserts in the urceolus 33.Free-piston 5 slided on the interior week of sleeve 84.

Step 32a upper edge periphery below flange 32 forms.Urceolus 33 engages and is fixed by welding on the step 32a with the periphery of step 32a.When finishing, prevent the axial displacement of sleeve 84 and prevent the radial displacement of sleeve 84 by urceolus 33 by step 32a and lid 34 respectively.

When assembling during vibration damper, in advance with sleeve 84, be housed in wind spring 6 and 56 and free-piston 5 assemble case 30 wherein, when finishing the assembling of housing, inner core 31 is threaded on the male thread portion 8b on the top of piston rod 8.Operation applies torque to urceolus 33 although be threaded, though at urceolus 33 owing to when this torque and slightly deformed, also can not produce any influence to sleeve 84.Therefore, axial displacement stably in the time of can guaranteeing that free-piston 5 slides on the interior week of sleeve 84.When urceolus 33 and step 32a are welded together in mode similar to the above, because the distortion of flange 32 that welding operation may cause or urceolus 33 can not produce adverse influences to sleeve 84.What therefore, free-piston 5 can held stationary endwisely slips.

With reference to Fig. 9 the second embodiment of the present invention is described.

This embodiment is different from the housing 30 that first embodiment's part is pressure chamber R3 and is arranged on main piston 2 tops, and in other words, the housing 30 of pressure chamber R3 is arranged on active chamber R1 one side.

Housing 30 was installed to the minor radius section 8a of piston rod 8 in piston 2 top positions before assembling piston 2, stacked leaf valve V1, V2 and brake component 28,29.After housing 30 was installed, brake component 28, stacked leaf valve V1, piston 2, stacked leaf valve V2 and brake component 29 were installed to minor radius section 8a successively.Nut N is fastened to the male thread portion 8b on the minor radius section 8a top.Under this mode, housing 30 is fixed on the precalculated position of piston rod 8.

Free-piston 5 is housed in the pressure chamber R3 of housing 30.Pressure chamber R3 is divided into upward pressure chamber R3A and downforce chamber R3B by free-piston 5 in the same manner as in the first embodiment.

In this embodiment, the second channel 4a of active chamber R1 and upward pressure chamber R3A and throttle orifice 11 comprise a plurality of through holes 94 in the upper-end surface that is arranged on housing 30 in the connection.The third channel 4b of active chamber R2 and downforce chamber R3B comprises the passage 41 that passes minor radius section 8a setting under connecting.Throttle orifice 12 is arranged in the passage 41.

Housing 30 comprises along the circle tube member 92 of downward direction opening and is fixed to annular plate member 91 on the opening of circle tube member 92 by crimp.The upper end closed of circle tube member 92.The axial displacement of housing 30 is by the step and brake component 28 restrictions in the upper end of the minor radius section 8a of piston rod 8 of vertical retaining plate member 91.

The through hole 93 of assembling piston rod 8 forms in the upper-end surface of circle tube member 92.Through hole 94 is not forming with 93 position overlapped places, hole.In the drawings, show two holes 94.Yet the quantity in hole 94 can increase arbitrarily according to the setting of aforesaid flow coefficient C 2 and C3 or reduce.

Free-piston 5 is included in goes up outer peripheral portion 98 that slides and the interior circumferential portion 100 of sliding in the interior week of circle tube member 92 on the periphery of piston rod 8.

Free-piston 5 slides on the interior Zhou Erzhe of the periphery of piston rod 8 and circle tube member 92.Therefore, can prevent the central axis of free-piston 5 and circle tube member 92 central axis and with the relative displacement of the central axis of piston rod 8, and the relative tilt between these central axis, the slip resistance that suppresses free-piston 5 thus improves undesirablely.

Be formed between the interior circumferential portion 100 and outer peripheral portion 98 of free-piston 5 towards rightabout two annular slots 97 and 99 in the axial direction.The wind spring 56 of the upper-end surface butt of one end and circle tube member 92 is housed in last annular slot 97.The wind spring 6 of one end and board member 91 butts is housed in the prone annular slot 99.Limited the radial displacement of wind spring 56 towards last annular slot 97.Prone annular slot 99 has limited the radial displacement of wind spring 6.In this embodiment, wind spring 6 and 56 is also corresponding to the spring S among Fig. 1 and 2.

This embodiment is identical with first embodiment, and the attenuation characteristic of vibration damper is determined by the spring constant K of compression area A, flow coefficient C 1, C2, C3 and the spring S of free-piston 5.The spring constant K of spring represents total spring constant of wind spring 6 and 56.

Flow coefficient C 1 depends on the flow resistance of stacked leaf valve V1 and V2.Flow coefficient C 2 depends on the quantity of through hole 94 and the flow resistance of each through hole 94.Flow coefficient C 3 depends on the flow resistance of throttle orifice 12.

Therefore, the setting of the spring constant K of the flow resistance of above-mentioned member, compression area A and spring S can be set break frequency Fa and Fb in any way.Damping coefficient ζ also can set in any way with respect to the variable quantity of inputted vibration frequency F.Therefore, the same with first embodiment in this embodiment, attenuation characteristic also can respond the inputted vibration frequency and set simply and in any way.

In this embodiment, through hole 94 connects upward active chamber R1 and upward pressure chamber R3A.Active chamber R2 and downforce chamber R3B under the passage 41 that forms in piston rod 8 connects.Yet, the through hole of active chamber R1 and downforce chamber R3B in the connection also can be set on board member 91.Can also utilize the inboard of piston rod 8 that the passage that connects following active chamber R2 and upward pressure chamber R3A is provided.

Through hole 93 can be formed has the radius that can engage with the periphery of minor radius section 8a.So being suitable for the periphery of the piston rod 8 above with being positioned at minor radius section 8a, the inner radial of board member 91 engages.This layout makes housing 30 can be mounted to vertically on rightabout piston rod 8.

According to this embodiment, when housing 30 was assembled on the piston rod 8, torque can not be applied on the housing 30.Therefore, housing can not cause distortion by torque, and can keep free-piston 5 axial displacement stably.

Describe with reference to Figure 10 and 11 pairs of third embodiment of the present invention.Those parts corresponding to those in the first embodiment are represented by identical reference character, and are omitted extra explanation.

With reference to Figure 10, in this embodiment, the throttle orifice 11 among first embodiment as shown in Figure 2 saves from the second channel 4a that is used for working oil.On the position of throttle orifice 12, variable orifice 120 is arranged among the third channel 4b.

With reference to Figure 11, the housing 30 among this embodiment comprises urceolus 33, flange 32 and covers 34 in the mode identical with housing shown in Figure 8.Inner core 31 and flange 32 form with integrative-structure.

Free-piston 5 flexibly is supported on neutral position in both sides by wind spring 6 and 56 in the mode identical with free-piston shown in Figure 85. Wind spring 6 and 56 constitutes spring S shown in Figure 10.

Sleeve 84 shown in Figure 8 saves from this embodiment, and the periphery of free-piston 5 is directly slided on the interior week of urceolus 33.

Bypass channel 42 is formed on and covers in 34 and active chamber R2 is communicated with downforce chamber R3B.

Circumference annular slot 51a is arranged on the periphery of cylindrical shape part 51 of free-piston 5.Annular slot 51a is connected with downforce chamber R3B by a plurality of through hole 51b that form on the lower end of free-piston 5 usually.On the other hand, the wall that a plurality of urceolus 33 by housing 30 are set makes the inboard of urceolus 33 and the throttle orifice 33a that following active chamber R2 is connected.

When free-piston 5 flexibly was supported on the neutral position by wind spring 6 and 56, perhaps when the displacement of free-piston 5 did not exceed prespecified range, throttle orifice 33a was formed on the position with respect to annular slot 51a.When the displacement of free-piston 5 exceeded prespecified range, a part of opening of throttle orifice 33a and the outer circumferential face of cylindrical shape part 51 were overlapping, and the cross sectional area of throttle orifice 33a begins to reduce.When free-piston 5 moved to end of travel, in other words, when free-piston 5 and inner core 31 or when covering 34 lower end butt, the outer circumferential face of the cylindrical shape part 51 of throttle orifice 33a and free-piston 5 was overlapping fully.Throttle orifice 33a is closed under this state.Therefore, the outer circumferential face of throttle orifice 33a, annular slot 51a and cylindrical shape part 51 has constituted variable orifice 120.

In this embodiment, third channel 4b connects downforce chamber R3B and following active chamber R2.Third channel 4b comprises the passage that comprises variable orifice 120 and the bypass channel 42 parallel with variable orifice 120.

When the resistance in one of two passages improves gradually, the flow resistance of the working oil between downforce chamber R3B and the following active chamber R2, in other words, the flow resistance of third channel 4b improves gradually.

Free-piston 5 from the prespecified range of the displacement of neutral position by the vertical width of annular slot 51a profile with in the face of determining the position of the throttle orifice 33a of annular slot 51a.When free-piston 5 arrived end of travel, throttle orifice 33a was by the outer circumferential face complete closed of cylindrical shape part 51.After this, flowing of the working oil between downforce chamber R3B and the following active chamber R2 only realized by bypass channel 42.At this moment, the flow resistance in the third channel 4b is in maximum value.

Replacement is provided with bypass channel 42 in lid 34, even can make throttle orifice 33a adapt to their also not exclusively sealings when free-piston 5 arrives end of travel.

In this embodiment, when free-piston 5 when the displacement of neutral position is in the prespecified range, the damping force characteristic can be determined by the compression area A of flow coefficient C 1, C2, C3, free-piston 5 and the spring constant K of spring 6.

Flow coefficient C 1 depends on the flow resistance of stacked leaf valve V1 and V2.Flow coefficient C 2 depends on the flow resistance of second channel 4a.Flow coefficient C 3 depends on the mobile resistance that applies by the variable orifice 120 that constitutes third channel 4b and 42 pairs of oil of bypass channel.

When free-piston 5 when the displacement of neutral position exceeds prespecified range, variable orifice 120 improves the flow resistance of third channel 4b gradually.When free-piston 5 when pressure chamber R3A or pressure chamber R3B move to the limit, in other words, when free-piston 5 arrived end of travels, the flow resistance in the third channel 4b arrived maximum value.Free-piston 5 is the evidence that acts on the high amplitude of the vibration on the vibration damper to the displacement of end of travel.

When the vibration frequency that acts on vibration damper was high relatively, vibration damper was created in the low relatively damping force in the prespecified range.When free-piston 5 exceeded prespecified range, the flow resistance in the third channel 4b improved gradually.The travelling speed of free-piston 5 reduces, and the flow of the working oil in passage 4a, the 4b also reduces.As a result, flow through the amount increase of the working oil of first passage 3.Owing to produce big damping force by stacked leaf valve V1, the V2 that constitutes deamplification force generating member 10, so the damping force that vibration damper produces improves gradually.

After free-piston 5 arrives end of travel, the flow vanishing of the working oil in passage 4a, the 4b.When vibration damper continued stroke, working oil only flowed in first passage 3, and vibration damper produces maximum attenuation power.

Therefore, even when the high amplitude vibration that moves to end of travel at free-piston 5 is imported into vibration damper, damping force can not change apace yet, and the response stroke distances improves reposefully.These characteristics can similarly be applied to the expansion stroke or the compression stroke of vibration damper.

Even have the vibration of high-frequency high amplitude when being transfused to, vibration damper can not change the damping force that is produced fast yet, can improve the riding comfort of vehicle.Especially, the rapid change of damping force in car body, produce the vibration or owing to the resonance with hood of vehicle produces noise.This embodiment has avoided this phenomenon, can improve the riding comfort of vehicle thus.

In this vibration damper, free-piston 5 in the mode identical with first and second embodiments by wind spring 6 and 56 elastic support in the neutral position.Therefore, can respond the stable damping force of stroke distances generation of vibration damper.Variable orifice 120 responds the displacement of free-pistons 5 and changes damping force.Therefore, in this vibration damper, stroke distances is accurately corresponding with damping force.Usually like this, can obtain stable damping force characteristic.

Replacement is provided with variable orifice 120 between downforce chamber R3B and following active chamber R2, can between upward pressure chamber R3A and last active chamber R 1 throttle orifice be set, and in other words, in second channel 4a throttle orifice is set.Can in second channel 4a and third channel 4b, variable orifice be set all.As selection, can variable orifice 120 be set and in another passage, fixed orifice be set in one in passage 4a and 4b.

With reference to Figure 12 A-12C, the shape of cross section of throttle orifice 33a can have several variations.

The shape of cross section of throttle orifice 33a can be the triangle shown in Figure 12 A, can be fan-shaped shown in Figure 12 B, perhaps can be the rhombus shown in Figure 12 C.In any one time of these situations, because each acutangulate bight is corresponding with the direction of displacement T of free-piston 5, therefore, the changing down of the section area of the passage of throttle orifice 33a is fixing basically.Therefore, compare with circular cross sectional shape, the variation of synthetic damping force is a balance.

With reference to Figure 13, a plurality of through hole 51b among the 3rd embodiment have several variations.

At this, each through hole 51b tilts to the central axis of free-piston 5.When through hole 51b tilted in this mode, the intensity of guaranteeing the wall thickness of periphery cylindrical shape part 51 and improving free-piston 5 became easier.This variation is especially preferred for the size that reduces free-piston 5.

With reference to Figure 14,120 structural variations describe to variable orifice with reference to the 3rd embodiment.

Replacement constitutes variable orifice 120 by the outer circumferential face of throttle orifice 33a, annular slot 51a and cylindrical shape part 51, can form variable orifice 120 by the inner peripheral surface of the urceolus 33 of throttle orifice 51c, annular slot 33b and housing 30.

Major diameter mouth 33c is arranged on the urceolus 33 of housing 30, connects the inboard and the outside of housing 30 to replace throttle orifice 33a.Annular slot 33b is along circumferentially being formed on the inner peripheral surface of urceolus 33.Annular slot 33b with on the inner peripheral surface of urceolus 33, open the mouth 33c open communication.A plurality of throttle orifice 51c are arranged on the free-piston 5.

Throttle orifice 51c is communicated with downforce chamber R3B by a plurality of hole 51d that the lower end at free-piston 5 forms.

Throttle orifice 51c is arranged in the periphery of free-piston 5.When free-piston 5 flexibly was supported on the neutral position by wind spring 6 and 56, perhaps when the displacement of free-piston 5 did not exceed prespecified range, opened with respect to mouth 33b on the whole surface of the opening of throttle orifice 51c.When the displacement of free-piston 5 exceeded prespecified range, a part of opening of throttle orifice 51c and the inner peripheral surface of urceolus 33 were overlapping, therefore comprised that the cross sectional area of the passage of described throttle orifice begins to reduce.When free-piston 5 moves when arriving end of travel, in other words, when free-piston 5 and inner core 31 or when covering 34 lower end butt, the inner peripheral surface of throttle orifice 51c and urceolus 33 is overlapping fully and seal.

Under this mode, owing in urceolus 33 rather than in free-piston 5, annular slot is set, so the intensity of free-piston 5 is improved.Thereby this variation is especially preferred when the size of free-piston 5 must reduce.

With reference to Figure 15, the fourth embodiment of the present invention is described.

This embodiment and second embodiment are similar, but are that with second embodiment's difference variable orifice 120 is arranged among the second channel 4a that is connected active chamber R1 and upward pressure chamber R3A.

Variable orifice 120 comprises the inner peripheral surface of the circle tube member 92 of annular slot 98a, throttle orifice 92a and housing 30.

Annular slot 98a is along on the outer circumferential face of the outer peripheral portion 98 that circumferentially is formed on free-piston 5.Annular slot 98a is communicated with upward pressure chamber R3A by a plurality of through hole 98b that form on the upper end of outer peripheral portion 98 usually.

Throttle orifice 92a is arranged in the wall of circle tube member 92 and active chamber R1 is connected with the inside of circle tube member 92.Throttle orifice 92a flexibly is supported on by wind spring 6 and 56 at free-piston 5 under the state of neutral position or does not exceed the position that is formed under the state of prespecified range in the face of annular slot 98a in the displacement of free-piston 5.When the displacement of free-piston 5 exceeded prespecified range, a part of opening of hole 92a and the outer circumferential face of outer peripheral portion 98 were overlapping, comprised that thus the cross sectional area of the passage of throttle orifice 92a begins to reduce.When free-piston 5 moves when arriving stroke terminal, in other words, when the upper end of free-piston 5 and circle tube member 92 or board member 91 butts, the outer circumferential face of throttle orifice 92a and outer peripheral portion 98 is overlapping fully and seal.Therefore, in this embodiment, the outer circumferential face of the outer peripheral portion 98 of throttle orifice 92a, annular slot 98a and free-piston 5 has constituted variable orifice 120.In addition, hole 94 and variable orifice 120 have constituted second channel 4a.

In this embodiment, can form annular slot 98a forming on the outer peripheral portion 98 of free-piston 5 on throttle orifice 92a and the inner peripheral surface at the circle tube member 92 of housing 30.As selection, can tilt to improve the intensity of the outer peripheral portion 98 of free-piston 5 by making through hole 98b.

The content that the spy who submitted in Japan on June 6th, 2005 opens 2005-164984 and the spy that submitted in Japan on September 17th, 2005 opens 2005-263221 is hereby incorporated by.

Although below describe the present invention with reference to some embodiment of the present invention, the present invention is not limited to above-described embodiment.Those skilled in the art will make modifications and variations to above-described embodiment within the scope of the claims.

For example, vibration damper is described as the single tube type in above embodiment.But, the present invention also can be applicable on the vibration damper of two-tube type, the vibration damper of this two-tube type is housed in pipe ring-type reserve zone interior and formation storage working oil between cylinder body 1 and described pipe with the outside of cylinder body 1, and perhaps the present invention also can be applicable to be provided with in the outside of cylinder body 1 vibration damper of separate storage jar.

In addition, can arrange pressure chamber R3 in the outside of cylinder body 1.

Claims (26)

1. one kind and bearing spring are side by side between the wheel of vehicle and the vibration damper between the car body, and it comprises:

Cylinder body (1);

The main piston (2) that described cylinder body (1) is divided into first active chamber (R1) and second active chamber (R2);

The first passage (3) that described first active chamber (R1) and described second active chamber (R2) are connected under first-class dynamic resistance;

By two pressure chambers (R3A, R3B) that free-piston (5) is separated, described free-piston (5) has predetermined compression area (A);

The second channel (4a) that one (R3A) in described first active chamber (R1) and described two pressure chambers (R3A, R3B) is connected under second flow resistance;

The third channel (4b) that another (R3B) in described second active chamber (R2) and described two pressure chambers (R3A, R3B) is connected under the 3rd flow resistance; And

Have predetermined spring constant (K) and described free-piston (5) flexibly be supported on the spring (S) of predetermined neutral position,

It is characterized in that, described first-class dynamic resistance, described second flow resistance, described the 3rd flow resistance, described spring constant (K) and described compression area (A) are configured to make the damping force of the vibration attenuation of described main piston (2) to reduce along with the raising of the vibration frequency of described main piston (2), wherein, the reduction feature of described damping force is by representing through the curve of two flex points (Fa, Fb).

2. vibration damper according to claim 1, it is characterized in that it is high and than in the low zone of the resonant frequency of the not mounting spring of described vehicle that described first-class dynamic resistance, described second flow resistance, described the 3rd flow resistance, described spring constant (K) and described compression area (A) are configured to make that the frequency (Fa, Fb) of described two flex points is in resonant frequency than the mounting spring of described vehicle.

3. vibration damper according to claim 1, it is characterized in that, described spring (S) comprises the wind spring (56) in (R3A) being arranged in described two pressure chambers (R3A, R3B) and is arranged in another (R3B) interior wind spring (6) in described two pressure chambers (R3A, R3B), make described free-piston (5) support in the opposite direction, and described predetermined spring constant (K) is equivalent to the synthetic spring constant of described two wind springs (6,56) by two wind springs (6,56).

4. vibration damper according to claim 1 is characterized in that, described two pressure chambers (R3A, R3B) are formed on the inboard of the housing (30) that is fixed on the described main piston (2) and are separated by the free-piston (5) that is housed in the described housing (30).

5. vibration damper according to claim 4, it is characterized in that, also comprise the piston rod (8) protruding and that link to each other with described main piston (2) from described cylinder body (1) vertically, this piston rod (8) passes described first active chamber (R1), described housing (30) is fixed to described main piston (2) in described second active chamber (R2), described housing (30) comprises the inner core (31) that is threaded on the described piston rod (8), cover the outside of described inner core (31) and have the urceolus (33) of opening end, the flange (32) that connects described urceolus (33) and described inner core (31), and the lid (34) that seals the described opening end of described urceolus (33), described two pressure chamber (R3A, R3B) (R3A) in is formed between described flange (32) and the described free-piston (5), described two pressure chamber (R3A, R3B) another in (R3B) is formed between described free-piston (5) and the described lid (34), described second channel (4a) is formed in the described piston rod (8) also with described first active chamber (R1) and described two pressure chamber (R3A, R3B) one in is connected, and be included in the described third channel (4b) in the hole (4b) that described lid (34) go up to form will described second active chamber (R2) and described two pressure chamber (R3A, R3B) another in is connected.

6. vibration damper according to claim 5 is characterized in that, described inner core (31), described flange (32) and described urceolus (33) form with integrative-structure.

7. vibration damper according to claim 5, it is characterized in that, described inner core (31) and described flange (32) form with integrative-structure, and described flange (32) and described urceolus (33) are fixing by welding, described vibration damper also comprises the sleeve (84) that inserts in the described urceolus (33), slides so that the periphery of described free-piston (5) can go up at described sleeve (84).

8. vibration damper according to claim 5 is characterized in that, the external shape in the cross section of described urceolus (33) is the shape except that positive circle.

9. vibration damper according to claim 4, it is characterized in that, also comprise the piston rod (8) protruding and that link to each other with described main piston (2) from described cylinder body (1) vertically, this piston rod (8) passes described first active chamber (R1), described housing (30) comprises the inner core (31) that is threaded on the described piston rod (8), cover the urceolus with closed end (33) in described inner core (31) outside, and the flange (32) that connects described urceolus (33) and described inner core (31), described two pressure chamber (R3A, R3B) (R3A) in is formed between described flange (32) and the described free-piston (5), described two pressure chamber (R3A, R3B) another in (R3B) is formed between the bottom surface and described free-piston (5) of described urceolus (33), described second channel (4a) is formed in the described piston rod (8) also with described first active chamber (R1) and described two pressure chamber (R3A, R3B) one (R3A) in is connected, described third channel (4b) is included in the hole (4b) that forms in the bottom surface of described urceolus (33), described inner core (31) and described flange (32) form with integrative-structure, and described flange (32) and described urceolus (33) interfix by crimp.

10. vibration damper according to claim 4, it is characterized in that, also comprise the piston rod (8) protruding and that link to each other with described main piston (2) from described cylinder body (1) vertically, this piston rod (8) passes described first active chamber (R1), described housing (30) is fixed to described main piston (2) in described first active chamber (R1), described housing (30) comprises the board member (91) on the periphery that is fixed to described piston rod (8), and be fixed to the barrel member with closed end (92) on the periphery of described board member (91), described piston rod (8) passes described barrel member (92) and described board member (91) respectively, described free-piston (5) slides on the periphery of described piston rod (8) in last slip of the interior week of described barrel member (92) and described free-piston (5), described two pressure chamber (R3A, R3B) (R3A) in is formed between the bottom surface and described free-piston (5) of described barrel member (92), described two pressure chamber (R3A, R3B) another in (R3B) is formed between described board member (91) and the described free-piston (5), second channel (4a) comprises the hole (94) on the bottom surface that is formed on described barrel member (92), this hole (94) is with described first active chamber (R1) and described two pressure chamber (R3A, R3B) one (R3A) in is connected, third channel (4b) comprises the passage (41) that is formed in the described piston rod (8), and this passage (41) is with described second active chamber (R2) and described two pressure chamber (R3A, R3B) another in (R3B) is connected.

11. vibration damper according to claim 10, it is characterized in that, described free-piston (5) be included in periphery and between interior week in the axial direction towards rightabout two annular slots (97,99), described spring (S) comprises and is housed in described two annular slots (97,99) in one in and the wind spring (6) between described board member (91) and described free-piston (5), and be housed in described two annular slots (97,99) in another in and between the bottom surface of described barrel member (92) and the wind spring (56) between the described free-piston (5), described free-piston (5) is by described two wind springs (6,56) support in the opposite direction.

12., it is characterized in that described third channel (4b) is constructed such that described the 3rd flow resistance responds described free-piston (5) from the displacement of neutral position and improve according to any described vibration damper in the claim 1 to 11.

13. vibration damper according to claim 12 is characterized in that, described third channel (4b) is constructed such that described the 3rd flow resistance became maximum value when proper described free-piston (5) arrived end of travel.

14. vibration damper according to claim 12 is characterized in that, described third channel (4b) is constructed such that described the 3rd flow resistance remained fixed value when the displacement of proper described free-piston (5) remained in the prespecified range.

15. vibration damper according to claim 12 is characterized in that, described third channel (4b) comprises the variable orifice (120) that is used to change described the 3rd flow resistance.

16. vibration damper according to claim 15, it is characterized in that, described variable orifice (120) comprises the displacement that responds described free-piston (5) and the annular slot (51a that is shifted relatively, 33b) and fixed orifice (33a, 51c), described annular slot (51a, 33b) and fixed orifice (33a, 51c) be arranged such that as long as described free-piston (5) remains in the prespecified range from the displacement of described neutral position, then described fixed orifice (33a, whole section area 51c) is in the face of described annular slot (51a, 33b), and described fixed orifice (33a, 51c) in the face of described annular slot (51a, section area 33b) exceeds described prespecified range along with described free-piston (5) moves and reduces.

17. vibration damper according to claim 16, it is characterized in that described third channel (4b) comprises that also bypass is in described variable orifice (120) and bypass channel (42) that described second active chamber (R2) is linked to each other with another (R3B) in described two pressure chambers (R3A, R3B).

18. vibration damper according to claim 16 is characterized in that, the shape of cross section of described throttle orifice (33a, 51c) is the polygonal that comprises towards the bight of the acute angle of the direction of displacement of described free-piston (5).

19. vibration damper according to claim 12 is characterized in that, described third channel (4b) comprises the hole (51b) in the part that is arranged on described free-piston (5), and this hole (51b) tilts with respect to the direction of displacement of described free-piston (5).

20., it is characterized in that described second channel (4a) is constructed such that described second flow resistance responds described free-piston (5) from the displacement of described neutral position and improve according to any described vibration damper in the claim 1 to 11.

21. vibration damper according to claim 20 is characterized in that, described second channel (4a) is configured to that described second flow resistance becomes maximum value when described free-piston (5) arrives end of travel.

22. vibration damper according to claim 20 is characterized in that, described second channel (4a) is configured to that described second flow resistance remains fixed value when the displacement of described free-piston (5) remains in the prespecified range.

23. vibration damper according to claim 20 is characterized in that, described second channel (4a) comprises the variable orifice (120) that is used to change described second flow resistance.

24. vibration damper according to claim 23, it is characterized in that, described variable orifice (120) comprises the displacement that responds described free-piston (5) and annular slot (98a) and the fixed orifice (92a) that is shifted relatively, described annular slot (98a) and described fixed orifice (92a) are arranged such that as long as described free-piston (5) remains in the prespecified range from the displacement of described neutral position, the whole section area of then described fixed orifice (92a) is in the face of described annular slot (98a), and described fixed orifice (92a) exceeds described prespecified range in the face of the section area of described annular slot (98a) along with described free-piston (5) moves and reduces.

25. vibration damper according to claim 23, it is characterized in that described third channel (4b) comprises that also bypass is in described variable orifice (120) and bypass channel (94) that described first active chamber (R1) is connected with (R3A) in described two pressure chambers (R3A, R3B).

26., it is characterized in that described first-class dynamic resistance is configured to bigger than described second flow resistance and described the 3rd flow resistance according to any described vibration damper in the claim 1 to 11.

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