WO2012161601A1

WO2012161601A1 - Clutch

Info

Publication number: WO2012161601A1
Application number: PCT/PL2011/000062
Authority: WO
Inventors: Krysztof CIEŚLAK
Original assignee: Uniwersytet Mikotaja Kopernika
Priority date: 2011-05-20
Filing date: 2011-06-24
Publication date: 2012-11-29
Also published as: WO2012161601A8; PL394953A1

Abstract

The subject of this invention is a clutch with a locking key (wedge) intended primarily for use as a locking element of differential mechanisms, as well as an inter- axle clutch used in wheeled vehicles, proposed in two design solutions characterized in that it rotates around the rotation axis (1), whereas housing (2) may rotate at a different rate than elements (31, 5 and 6) which always have the same rotational speed.

Description

Clutch

This invention is primarily intended for use as the locking element of differential mechanisms, as well as, the inter-axle clutch used in wheeled vehicles.

Several differential mechanisms have been recognized amongst others in the following publications: GB19880014226, GB19880016712, US19950495417 , US19920969727 , W01993US08280 and US19910712667, W01992US03518. The above- mentioned solutions utilize the worm gear's working principle, its self-locking ability, where it transfers the torque, and the teeth of interacting elements overlap each other at a certain angle. The angle of the teeth utilized in the above mentioned solutions is such, that any differences in rotational speeds of individual elements causes their reciprocal resistive overlapping, thus eliminating the disadvantages of the classic mechanism, such as the transfer of the entire torque onto the slipping wheel or axle.

Specific inter-axle clutches controlled via external means, which replace the central differential mechanisms in sport - utility vehicles have also been identified, particularly those described in the following publication: WO2007SE5066520070919. The above solution utilizes a wet multi-disc clutch disengaged hydraulically in order to engage an additional axle. Many factors are responsible for the connection quality and integrity such as the oil pressure likely to be achieved in the releasing mechanism or the correctness of the complex control algorithm.

The essence of the solution, as far as the invention is concerned, is that the clutch rotates around an axis of rotation, in which the housing can have different rotational speed than the elements rotating at a constant speed. Consequently the drive shaft is uniform with the crown gear where a helical gear pattern is capable of to- and-fro motion in a radial direction when a rotational speed difference between the elements occurs. The inner surface of the housing is built on the basis of a circle with a radius greater than the circle forming the largest outline of the element and having its center at a spot other than the center of the circle described. The rings rest against the lower portion of the gear teeth, which are responsible for the permanent abutting of their external j planes to the surface; as a result working chambers are formed between the outer crown gear, the surface, and the gear teeth. Radial channels are honed into the element, so that fluids can flow from the working chambers in the direction of the remaining spaces inside the device, where the mechanism is controlled by the means of a valve regulated via a rod connected to it by a bar. The elements are mounted in the hollow channels of the shaft and can perform reciprocating motion in a direction parallel to the axis of rotation. All other unbound, internal spaces inside the mechanism are filled with an oil agent, where seals are fitted between the elements in order to protect against any leakage of the above mentioned agent. The coupling connection of the two kinematic forces of the drive shaft and the outgoing shaft is uniform with the housing.

The solution offered by the aforementioned invention does not differentiate between rotational speeds of the individual elements in a resistive manner, and thus does not impair the fuel economy or cause the excessive wear of the torque transmitting elements. It is capable of transmitting up to 100% torque to the wheel/axle with better traction. It does not modify its working parameters during operation. The solution offers the possibility to use a less sophisticated control algorithm resulting from the simplification of the clutch adjustment. To adjust the clutch it is necessary to supply a force perpendicular to the force being transmitted, which is disproportionately smaller than the latter and which greatly reduces the disengaging system. During the differentiation of rotational speeds via the clutch, a slight loss of transmitted power occurs, while - due to its specific construction - the clutch is being partially cooled inside the mechanism, and thus requires no additional systems regulating thermal balance.

A sample design of the invention has been shown in the drawings, of which Fig. 1 shows the cross section of the clutch together with the locking oil wedge. Fig. 2 shows a longitudinal intersection of the clutch intended for use in differentials and Fig. 3 shows a longitudinal intersection of the clutch intended for use as an inter-axle clutch.

The invention based clutch solution is made out in the two proposed construction designs and is characterized by the fact that it rotates around an axis of rotation, while the housing .2 may have a different rotational rate than elements 3, 5, 6, which always rotate at the same rate. Drive shaft 3 is■ uniform with the crown gear 5. In element 5_ radial notches _9 are made, they hold gear teeth 6 capable of to-and-from motion in the radial, when a rotational speed difference exists between the elements 3_, 5_ and element 6. The inner surface 1_ of the housing 6 is created on a basis of a circle with a radius greater than the circle forming the largest outline of element 5_ and having its center at a spot other than the center of the circle described. The rings 8_^ rest against the lower portion of the blades 6 and are responsible for their permanent abutting to the surface 1_ with their external planes. As a result working chambers 15 are formed between 201

the outer crown gear outline 5, the surface 1_ and the J blades 6. Radial channels 13 are hollowed in element 5, so that the fluid can flow from the working chambers 15 towards the remaining spaces inside the device. Valve 10, regulates the flow of fluids^ is controlled via rod jL2 and is connected to it by the means of a bar 11. In order to adjust the valve 1 , an external force is applied onto element 12. Elements 10, 11, 12 are mounted in the hollow channels of the shaft 3 and can initiate a reciprocating motion in a direction parallel to the axis of rotation 1. All other unbound, internal spaces inside the mechanism are filled with fluid. Seals 1_ are applied between elements 2, 3 and 11 in order to protect against any possible fluid leakage. The solution is illustrated on Fig. 3 and shows the coupling connection of two kinematic forces of the drive shaft 3 and the outgoing shaft _ which is uniform with the housing 2. Remaining elements are identical as in the solution shown on Fig. 2.

The clutch together with the locking oil wedge as shown in the longitudinal cross-section in Fig. 2 makes an integral part of the lockable differential mechanism, where J the housing 2 is directly connected to a housing of the classical differential mechanism, and the shaft 3 is uniform with a half-shaft protruding from the mechanism. The working principle of the clutch is such that it rotates, along with the differential mechanism connected to it as described above in relation to the axis of rotation _1. Should the vehicle travel along a curve the differences in rotational speed shall occur between the housing and the half-shaft, thus the rotational rate differences occur in the clutch between housing 2 and both shaft 3 and collar flange 5. The blades 6 mounted in element 5 and pressed against the surface 7 via rings 8 perform to-and-fro motion and spaces 15 change their volume by squeezing out or drawing in fluid from the remaining internal spaces of the clutch through the channels Y3. Valve lj) regulates the flow of fluid by performing a plane motion in an axis parallel to the axis of the clutch rotation to the cover of the channel inlet _13, which is adjusted by the means of an external force applied onto the rod L2 connected to it by the means of a bar 11. The flow of the fluid is controlled by valve 10_^ not cover the inlet to channels 13, than the unobstructed flow of fluids between the chambers 15, which changes their volumes, whereas they do not cause any significant resistance during differentiation of the rotational rates by the differential mechanism under its nominal operational conditions. Should it however be necessary to extort the reduced rotational speed difference on the mechanism, then valve 1_0 may completely or partially cover the inlet to channels 3 by applying an external force. Fully covering the inlets to channels 13 by valve _10 means the total confinement of the oil agent within the working chambers L5, which shall equalize the rotation of element 2 with shaft 3_ and element 5_, and full locking the differential mechanism configured within the clutch as previously described.

The clutch together . with the locking oil wedge as shown in the longitudinal cross-section in Fig. 3 is a design solution for the clutch intended for enabling and disengaging additional drive axles. The working principle remains the same as in the solution presented in Fig. 2, whereas in Fig. 3 an arrangement for two kinematic forces has been proposed, where the drive shaft 3 does not protrude through the clutch, but ends within the clutch transmitting torque onto housing 2, which is uniform with drive shaft _. Power transfer is regulated in accordance with a scheme identical with the one presented for the solution in Fig. 2, which uses the flow of an oil agent regulated by the valve 10_^ while rotational rate differences occur, or power transfer is possible without the occurrence of rotational rates by locking the clutch by completely covering the inlets to channels 3 by valve 10 and confining of the fluid in working chambers 15.

In both design solutions, clutches are adjusted externally by applying force to rod VI . This force can be generated in any manner. The adjustment can be done manually or may be controlled automatically. The advantage

J of such an adjustment is simpler control over the rotational differences by covering the inlets to channels 13 by valve 1() and extorting the reduced oil agent flow. The oil, regardless of the force being transmitted by the clutch, will flow through the interstice at approximately the same rate, which will be reflected by maintaining a slightly deflected constant rotational difference by the clutch. In addition, the energy spent on oil flow is smaller than the frictional losses occurring due to friction of the conventional clutch discs, which are characterized by an increase of energy consumption along with the torque being transmitted during rotational differentiation. The invention based clutch solution does not require a cooling system, as, due to its specific design, the oil in the working chambers \ b_ is half cramped and half subjected to negative pressure. Oil flowing through channels 13_ exhibits exactly the same behavior. In half of these channels it is highly compressed which results in high velocity, which generates heat, but in the second half of the channels it is subjected to a

I simultaneous sudden negative pressure, which results in the generation of the lower temperature. Another important advantage of the clutch is the quality of connection being initiated, realized in a completely smooth manner, where no outside factors, such as the current travel of a vehicle along a curve or the actual movement of the vehicle^ have any impact on the process.

The main purpose of the clutch with an oil wedge based on the described invention are the locking units of differential mechanisms as well as clutches engaging additional drive axles in all possible utility groups, such as :

Sports cars, heavy utility vehicles, construction equipment and farm tractors. This clutch is a compatible solution, as it can serve the role of an electronically controlled locking of differential mechanisms found in sport - utility vehicles, as well as an electronically controlled clutch engaging an additional drive axle when the primary drive axle slips. It can also serve as a manually operated differential locking for heavy equipment, such as farm, construction and heavy-duty vehicles, as well as, a manually operated clutch engaging an additional drive axle of the vehicles mentioned above.

Claims

Patent claims

1. Clutch rotating around the axis of rotation, characterized in that housing 2 may have a different rotational rate than elements (3, 5_ and 6) , which always have the same rotational speed, where as drive shaft (3_) is uniform with crown gear (_5) with radial notches (9) ; successively teeth (6) capable of to-and- from motion in the radial direction are placed in the notches, while a rotational speed difference exists between elements (3), (5), and element (6)

2. In compliance with claim 1, the clutch is characterized in that the inner surface (_7) of housing (6) is built on a basis of a circle of a radius greater than the circle forming the largest outline of element (5_) and having its center at a spot other than the center of the circle described.

3. In compliance with claim 2, the clutch is characterized in that the rings (8!) rest against the lower portions of teeth (6) and are responsible for their permanent abutting to surface ( ) with their external planes; as a result of that, working chambers 15 are formed between the outer collar flange outline 5, surface 7 and blades 6.

4. In compliance with claim 3, the clutch is characterized in that, radial channels (13) are hollowed in element (_5) , so that fluid can flow from working chambers (15) towards the remaining spaces inside the device; valve (10) adjusted via rod (12) connected to it by the means of bar (11) regulates the oil flow, whereas elements 10, 11, and 12 are mounted in the hollow channels of shaft (3) and can initiate a plane motion in a direction parallel to the axis of rotation (1) .

5. In compliance with claim 4, the clutch, is characterized in that, all the other unbounded, internal spaces inside the mechanism are filled with an oil agent, while seals (.14) are applied between elements 2, 3 and 11) in order to protect against any fluid leakage.

6. In compliance with claim 5, the clutch , is characterized in that, the coupling connection of two kinematic forces of the drive shaft {3} and the outgoing shaft (_4) which is uniform with the housing (2) .