DE19652785B4 - Release device with integrated displacement sensor for a hydraulically actuated friction clutch - Google Patents

Abstract

declutching (1) for a hydraulically operated Friction clutch (15) of vehicles with a housing (3), concentric with an internal combustion engine with a manual transmission connecting drive shaft (10) is arranged and in its recess (5) radially spaced from an inner wall (6) a guide sleeve (8) is used, on which an annular piston (11) is guided axially displaceable, the one radial distance between the guide sleeve (8) and the inner wall (6) bridged and thus an annular pressure chamber (12) limited, which is acted upon by a pressure medium, wherein the release device (1) furthermore for the travel detection of the annular piston (11) a sensor system (17a to 17e), characterized by an arrangement of the sensor system (17a to 17e), the one directly or indirectly arranged on the front side of the housing (3), circular ring designed Hall sensor (18), with a ring piston (11) enclosing Pulse generator (19a to 19e) cooperates.

Description

Territory of invention

The The invention relates to a release device for a hydraulic actuated Friction clutch of vehicles with a housing concentric to one arranged an internal combustion engine with a drive transmission connecting drive shaft is, and in the recess radially spaced to an inner wall inserted a guide sleeve is, on which an annular piston is guided axially displaceable, and the annular piston has a radial distance between the guide sleeve and the inner wall bridges and thus an annular Limited pressure chamber, which is acted upon by a pressure medium, the release device continues a sensor system comprises for travel detection of the ring piston.

background the invention

The increasing automation in vehicles requires refined, diverse Of control. In motor vehicles, clutch systems find application in a Pushing operation of the motor vehicle automatically turn off the engine, to utilize the kinetic energy with which the vehicle is moving becomes. To ensure a smooth flow of traffic, the engine must if necessary delay-free to be started. This often happens via flywheels whose moment of inertia over a corresponding double clutch are transmitted to the crankshaft of the engine can. For the function, d. H. the engaging behavior the automated clutch operation it is necessary to determine the exact position of the release bearing. To It is known to use sensors with which the position of the at the release bearing fix ring piston can be determined. The control structure the automated clutch operation provides that a Displacement of the annular piston, which is detected by the sensor, by means of pulses or Signals forwarded to an electronic unit for processing the state variables becomes.

From the DE 41 20 643 A1 is a release device for a hydraulically actuated friction clutch of vehicles known that can be equipped with Wegmeßeinrichtungen or travel detectors of different types. For example, the document shows a sensor that interacts with a separate slider. These additional components disadvantageously increase the space of the release device and the component size. Another displacement measuring device can be integrated within the slave cylinder. The sensor is formed by a metallic housing, spaced on the inner wall, a specially coated annular piston is guided. In this case, sensors with a variable resistance, alternatively with a variable capacitance or a variable induction, can be used to generate a stepless path signal. The sensor arrangements of this known release device require a disadvantageous space enlargement, or a special shield to achieve a trouble-free function or the use of special parts. All arrangements have in common a high production cost, which increases the production costs adversely.

Task of invention

Of the The present invention is based on the object, a sensor system to create that in the existing space of the release device for the realization a multiple function of individual components of the release device economical and space-optimized can be integrated.

Summary the invention

According to the invention this Problem solved by the characterizing features of the main claim. After that comprises the invention is a sensor system that has a directly or indirectly frontally on the housing arranged annular shaped Hall sensor includes. The Hall sensor stands in an operative connection to a pulse generator, the Part of the ring piston is. The arrangement of the pulse generator provides for the creation of a space-optimized solution that the pulse generator the annular piston in compliance with the predetermined outer contour encloses.

From the US 47 05 151 the application of a Hall sensor in a release device for a hydraulically actuated friction clutch is known, which comprises a stepped sleeve which bears non-positively on the annular piston and the outside is enclosed by the coil spring and the axial portion is guided in the engaged position of the friction clutch close to the housing , This known sensor system requires a high manufacturing and assembly costs and has a non-practical design, since the sleeve is directly exposed to contamination and thus the function, ie the measured value can be influenced by the sensor.

In contrast, the invention shows a task-oriented arrangement of the individual components of the sensor system within the space available components of the release device. The frontal arrangement of the Hall sensor on the housing, preferably on the axially exiting from the housing portion in which the annular piston is guided, simplifies the assembly. Without great installation effort and the pulse generator according to the invention can be arranged on the annular piston. As a pulse generator to a thin-walled band-shaped, electrical conductor that is attached to the annular piston, for example, by gluing is sufficient. Due to the functioning of a Hall sensor, which measures a so-called Hall voltage as an analogue size and directly links this with the strength of a magnetic field, magnetic fields can be measured directly. Hall sensors measure movements or positions by preferably moving a permanent magnet towards or away from the sensor. Alternatively, a measuring arrangement can be provided, the construction of which provides a sensor assigned directly to the permanent magnet. The case, for example, the permanent magnet biased Hall sensor can cooperate with a ferromagnetic, a conductor structure having pulse generator. Since Hall sensors require no mechanical elements and the voltage measurement takes place contactlessly and thus wear-free, hall sensors are maintenance-free and achieve a service life that exceeds that of the vehicle.

In advantageously possible the sensor system according to the invention, in which the Hall sensor and the pulse generator within the component configuration of the housing and the annular piston are arranged, the possibility that these Components dependent on demand upgradeable are.

A Embodiment of the invention provides to arrange in the housing an intermediate sleeve, which serves to hold the guide sleeve, the annular flange between a first end face of the intermediate sleeve and the housing is tense. At the opposite, oriented to the friction clutch end face of the intermediate sleeve the Hall sensor attached to the pulser, arranged on the ring piston, cooperates. The arrangement of the Hall sensor on the intermediate sleeve allows a Vorkomplettierung of these components, which can be mounted as a unit in the housing are.

Preferably comprises the sensor system according to the invention a pulse generator in an annular piston made of plastic is poured. This measure prevents damage of the pulser during the assembly and allows the use of a scraper ring between the housing or the intermediate sleeve and the annular piston, with the impurities from the lateral surface of the Ring piston can be removed to avoid impairment the mode of operation of the sensor system.

When Pulse generator is a ferromagnetic metal strip, which in the Ring piston is poured. The width of the metal strip corresponds while the maximum stroke of the release bearing.

to Ensuring exactly defined pulses or signals that for example, forwarded by the sensor system to an evaluation device be, the invention sees a ladder-shaped metal band in front. To generate a constant path signal over the entire adjustment of the ring piston are the ladder rungs the metal strip arranged exactly spaced. A pulse generator, its metal band to generate the same signals with several exact provided spaced ladder rungs, has the advantage that the signals for determining an exact position position of the annular piston of a counter, integrated in the evaluation circuit, to be registered.

The Invention includes furthermore a pulse generator in the form of a ladder-shaped Metal strip, at the ends ladder rungs in comparison to the rest Ladder rungs with a larger cross-section are arranged. Such a pulse generator generates a signal with a much higher one Stress at the reversal points compared to the stresses in the Intermediate area, since the Hall sensor due to the smaller sized ladder rungs a weaker one measuring signal detected. This Pulse generator combined with a logical link enables effective path detection and exact determination of reversal points.

alternative can be used as a pulse generator, a metal band application exclusively in the Range of reversal points, d. H. the end positions of the ring piston ladder rungs has, so that the with the Hall sensor associated Auswerteausschaltung exclusively a signal is transmitted when the friction clutch is in an end position. to It makes sense to distinguish the reversal points, ladder rungs to provide with divergent cross-sectional profiles, the direct different signals to the evaluation circuit.

It may also be advantageous, a cross-sectional profile of the ladder rungs to provide the metal strip, with divergent ramps designed to create directional impulses, thereby Evaluation circuit the respective direction of movement of the annular piston or the release bearing transferred becomes.

In an advantageous embodiment of the invention, the Hall sensor is provided with a scraper, which bridges a distance between the pulse generator and the Hall sensor. The good sliding scraper, for example made of felt, plastic or PTFE, has the task to remove the accumulated in the measuring range, for example, on the lateral surface of the annular piston impurities. With this measure, a Meßsignalverfälschung is effectively prevented, which can occur in particular by ferromagnetic particles.

The inventive arrangement of the Hall sensor on the front side of the housing or on an inserted in the intermediate housing intermediate sleeve allows a guide the sensor line on the outside of the housing. This results in an easily assembled, not the components of the release device influencing cable routing, the opposite of previous ones solutions has a significant cost advantage.

Farther represents the invention in the submitted end position of the release device a protected Location of the sensor system safe. The pulse generator is concentric from the intermediate sleeve and the Hall sensor enclosed by the inner ring of the release bearing.

Short description the drawings

Based on 1 to 7 the invention will be explained in more detail. Showing:

1 a longitudinal section through the release device according to the invention, in which the release bearing is shown in the engaged end position;

2 the release device according to 1 in which the release bearing is shown in a disengaged end position;

3 in a simplified, schematic representation of the sensor system according to the invention with a ladder-shaped metal strip as a pulse generator, the equally spaced ladder rungs and a position-positioned Hall sensor. The sensor system is associated with a diagram from which the signal waveform can be seen via the displacement path;

4 a sensor system that unlike 3 a pulse generator having two ladder rungs whose position coincides with the turning points of the ring piston;

5 one of the 4 corresponding sensor arrangement whose ladder rungs have a divergent cross-sectional profile for securing position of different signals;

6 a sensor arrangement whose pulse generator has a plurality of equally spaced guide rungs, wherein the ramps are designed differently from each other;

7 the structure of a sensor arrangement comprising a pulse generator whose end-side ladder rungs have a larger cross-sectional profile than the interposed ladder rungs.

Full Description of the drawings

The 1 and 2 show the structure of a release device 1 in half section. In 1 is a release bearing 2 in an engaged end position, ie the neutral position shown. The release device 1 has a housing 3 on, over a front 4 in the installed state at one in the 1 and 2 not shown gear housing is releasably attached. Centric is the housing 3 with a recess 5 provided an inner wall 6 has, on the one intermediate sleeve 7 centered and sealed in the housing 3 is used. Radially inwardly spaced to the intermediate sleeve 7 is still a guide sleeve 8th in the case 3 used. For position positioning of the guide sleeve 8th this has an annular flange 9 on, on the case 3 is supported and on the other the intermediate sleeve 7 is applied. The intermediate sleeve 8th Coaxially extends over a portion of a drive shaft 10 , which produces a drive connection between an internal combustion engine and a transmission, which in the 1 and 2 not shown. Between the guide sleeve 8th and the intermediate sleeve 7 is a radial distance bridging, annular shaped annular piston 11 arranged axially displaceable. The one pressure room 12 axially limiting annular piston 11 is axially displaceable by means of a pressure medium. In this case, the pressure medium passes through a housing 3 introduced feed bore 13 in the pressure room 12 , to achieve a displacement of the ring piston 11 and the associated release bearing 2 , A disengagement of the friction clutch 15 starts as soon as the release bearing 2 on release levers 14 the friction clutch 15 abuts, and ends as soon as the ring piston 11 in the 2 Pictured position of the ring piston 11 occupies, ie the annular piston 11 at an end stop 16 is applied.

To determine the position of the ring piston 11 and thus the friction clutch 15 serves a sensor system L7A consisting of a Hall sensor 18 or Hall generator and a non-contact related pulse generator 19a , The Hall sensor 18 is on the front side of the out of the housing 3 projecting free end of the intermediate sleeve 7 fixed in position. As a pulse generator 19a serves a lateral surface 20 of the ring piston 11 in which a ferromagnetic metal strip is integrated. To be sure position of a protected mounting position of the pulse generator 19a It makes sense, in a made of plastic ring piston 11 the pulse generator 19a pour. The formation of the release device 1 provides that the ring piston 11 in the in 1 shown end position on the ring flange 9 is supported. The ring piston 11 is a separate seal carrier 21 assigned, in the U-rings 22 . 23 are used, which has an annular gap between the annular piston 11 and the intermediate sleeve 7 or the annular piston 11 and the guide sleeve 8th caulk. In the engaged end position of the release device 1 (please refer 1 ) is the Hall sensor 18 on the outside of an inner ring 24 the release bearing 2 largely enclosed, so that it is protected from contamination and damage. A protected position also results for the pulse generator 19a in this end position of the ring piston 11 , the case of the intermediate sleeve 7 is surrounded. A sensor line 25 who have an in 1 and 2 not shown evaluation control with the Hall sensor 18 connects, is on the outer contour of the intermediate sleeve 7 or of the housing 3 fastened without necessary assistance or impairment of adjacent components. The pulse generator 19a , formed as a permanent magnet, has a ladder-shaped structure, whereby when passing through the ladder rungs 26 at the Hall sensor 18 a clocked signal results, which is supplied to the evaluation circuit for determination of the position position of the annular piston 11 and thus the friction clutch 15 ,

In 3 is the sensor system 17a schematically illustrated, which is associated with a diagram showing a pulse course over the displacement path "S". On the ordinate of the diagram the voltage "U" is plotted and on the abscissa the path "s". Due to the even spacing of the ladder rungs 26 As well as the rectangular cross-sectional structure of the ladder rungs results in a rectified pulse course over the displacement "S". The sensor arrangement 17a is suitable for a combination of an evaluation circuit in which a counter is integrated, so that the respective position of the annular piston due to the happened ladder rungs 26a the pulse generator 19a the exact position of the friction clutch can be determined. The Hall sensor 18 is a scraper immediately 27 assigned to the distance to the lateral surface 20 bridged. The scraper sliding on the lateral surface 27 effectively prevents impurities such. B. ferromagnetic particles distort the measurement signal. The insoluble, z. B. by gluing the Hall sensor 18 attached scrapers 27 is made of a lubricious material, such as felt, PTFE or plastic.

The 4 shows the sensor system 17b whose pulse generator 19b only over two ladder rungs 26b features, each at the endpoints of the pulser 19b are arranged and their position coincides with the reversal points of the annular piston 11 , The accompanying diagram shows that according to the formation of the pulse generator 19b with two ladder rungs 26b only two voltage excursions result, which as pulses or signals from the Hall sensor 18 be transferred to the evaluation circuit.

The sensor system 17c according to 5 also includes one with two ladder rungs 26c fitted pulse generator 19c , where the ladder rungs 26c have different cross sections. From the associated voltage diagram, it can be seen that the conductor rungs cross section directly influences the pulse voltage.

Another alternative embodiment of a pulse generator shows the 6 in which the ladder rungs 26d to achieve a directional signal or pulse each have differently shaped ramps. According to 6 show the ladder rungs 26d on the to the Hall sensor 18 pointing side a steep, ie vertical ramp on and on the side facing away from a flattened ramp. Corresponding to the cross section of the conductor, an asymmetrically designed signal curve results in the voltage diagram, which advantageously makes it possible to detect the direction in the evaluation circuit.

In 7 is the sensor system 17e shown, whose pulse generator 19e at the ends evenly sized ladder rungs 26e having. The between the ladder rungs 26e equally spaced arranged ladder rungs 26f have the same cross sections, but with respect to the end ladder rungs 26e smaller dimensions. This pulse generator 19e creates a voltage diagram at the reversal points, in the area of the ladder rungs 26e a significantly higher voltage "U ₂ " generated in comparison to the measuring signals in the area of the ladder rungs 26f whose voltage is specified as "U ₁ ". By means of a logical link, the voltage differences can be evaluated for the exact determination of the reversal points.

Claims (12)

Release device ( 1 ) for a hydraulically actuated friction clutch ( 15 ) of vehicles with a housing ( 3 ) concentric with a drive shaft connecting an internal combustion engine with a manual transmission ( 10 ) is arranged and in the recess ( 5 ) radially spaced to an inner wall ( 6 ) a guide sleeve ( 8th ) is inserted, on which an annular piston ( 11 ) is axially displaceably guided, which is a radial distance between the guide sleeve ( 8th ) and the inner wall ( 6 ) bridges and thus an annular pressure chamber ( 12 ), which is acted upon by a pressure medium, wherein the release device ( 1 ) continue to the travel detection of the ring piston ( 11 ) a sensor system ( 17a to 17e ), characterized by an arrangement of the sensor system ( 17a to 17e ), one directly or indirectly frontally on the housing ( 3 ) arranged annularly shaped Hall sensor ( 18 ) comprising an annular piston ( 11 ) enclosing impulse generator ( 19a to 19e ) cooperates. Release device according to claim 1, characterized in that the Hall sensor ( 18 ) frontally on an intermediate sleeve ( 7 ) arranged in the housing ( 3 ) is positionally positioned and on which an annular flange ( 9 ) of the guide sleeve ( 8th ) is supported. Release device according to claim 1, characterized in that the pulse generator ( 19a to 19e ) in an annular piston ( 11 ) is cast from plastic. Release device according to claim 1, characterized in that as a pulse generator ( 19a to 19e ) is provided a ferromagnetic provided with ladder rungs metal strip, which is designed as a permanent magnet. Release device according to claim 4, characterized by a ladder-shaped metal band whose ladder rungs ( 26a ) have a precisely defined spacing ( 3 ). Release device according to claim 4, characterized in that the sensor system ( 17e ) a pulse generator ( 19e ), consisting of a ladder-shaped metal band, which at the ends ladder rungs ( 26e ), between which equidistant, compared to the ladder rungs ( 26e ) smaller sized ladder rungs ( 26f ) are arranged ( 7 ). Release device according to claim 4, characterized by a pulse generator ( 19b . 19c ), the reversal points of the annular cylinder ( 11 ) accordingly with ladder rungs ( 26b . 26c ), which, when passing through the Hall sensor ( 18 ) Trigger signals which are registered by a counter integrated in an evaluation circuit. Release device according to claim 7, characterized in that the pulse generator ( 19c ) at the ends ladder rungs ( 26c ), which have a different cross-sectional profile ( 5 ). Release device according to claim 4, characterized in that the ladder rungs ( 26d ) have differently shaped ramps to achieve a directional signal ( 6 ). Release device according to claim 1, characterized in that the Hall sensor ( 18 ) with one, a distance between the pulse generator ( 19a ) and the Hall sensor ( 18 ) bridging scrapers ( 27 ) ( 3 ). Release device according to claim 1, characterized by a sensor system ( 17a to 17e ), which is a sensor line ( 25 ), which on the intermediate sleeve or on the housing ( 3 ) is attached. Release device according to claim 1, characterized by a sensor system ( 17a to 17e ) whose Hall sensor ( 18 ) in the engaged end position of the release device ( 1 ) on the outside of an inner ring ( 24 ) of the release bearing ( 2 ) is enclosed.