DE102021203731A1 - Release system for actuating a clutch and displacement measuring device for measuring a position of a piston along an axial direction - Google Patents

Abstract

A travel measuring device (255) for a release system for measuring a position of a piston (115) relative to a cylinder (105) along an axial direction (A) is proposed. The displacement measuring device (255) comprises a first measuring component (165) and a second measuring component (170), which form a measuring system for measuring a position of the piston (115) indicative of the relative position of the first and second measuring components (165, 170) to one another, wherein the first sensing component (165) is coupled to one of the piston (115) and cylinder (105) parts, wherein the second sensing component (170) is coupled to the other of the piston (115) and cylinder (105) parts and wherein the first measuring component (170) along the axial direction (A) is designed to be movable relative to the one part consisting of the piston (115) and cylinder (105).

Description

The present invention relates to a release system and a displacement measuring device for measuring a position of a piston along an axial direction.

In particular, pneumatically actuated, concentric release systems have become established as the standard in commercial vehicles for actuating a clutch. Such systems offer several advantages, including greater functional integration, a more compact design and the use of existing peripherals such as compressed air.

For control purposes, for example, such a release system requires information about a position of a piston that can be moved in order to actuate the clutch. Known path measuring devices are implemented, for example, in such a way that a signal generator or a sensor is coupled to the piston of the release system.

Clutch wear and tolerance fluctuations, such as installation tolerances or wobbling of an internal combustion engine, can increase a measurement path to be kept available in the sensor in the known path measuring devices. This can result in a restriction when selecting a technology on which the sensor is based. The structure of the sensor can also be complex and time-consuming for large measurement paths.

It can therefore be regarded as an object of the present invention to form an improved concept for a displacement measuring device.

This object can be solved with the help of the independent and dependent claims of the present disclosure.

According to a first aspect, the present invention relates to a displacement measuring device for measuring a position of a piston relative to a cylinder along an axial direction. The path measuring device comprises a first measuring component and a second measuring component, which form a measuring system for measuring a position of the piston indicative of the relative position of the first and the second measuring component to one another. The first sensing component is coupled to one of the piston and cylinder parts. The second sensing component is coupled to the other of the piston and cylinder parts. The first measuring component is movable along the axial direction in relation to the part made up of a piston and cylinder.

As in clutch release applications, the piston can disengage in the axial direction to actuate a clutch. For control purposes it may therefore be desirable to measure the position of the piston along the axial direction.

The first or the second measuring component can comprise a signal transmitter, for example a magnet, and can be coupled to the piston. The respective other measurement component can include a signal receiver, for example a magnetic field sensor, and can be arranged fixedly relative to the piston. In some exemplary embodiments, the signal transmitter and signal receiver can be interchanged.

The first and the second measurement component can be operatively connected in such a way that the first or the second measurement component uses a signal from the other measurement component, for example using a magnetic flux density, to measure the relative position of the first and second measurement component to one another. The position of the piston can be deduced from the relative position.

The first measuring component can be arranged such that it can move along the axial direction, for example via a rail or a guide. As a result, the relative position of the first and the second measuring component to one another can be set for an initial position of the piston, for example during installation or during operation of the displacement measuring device. In this way, installation tolerances and/or clutch wear can remain unconsidered in the case of a measurement path to be maintained in the sensor.

In some further exemplary embodiments of the distance measuring device, this also includes a fixing device which is designed to fix the first measuring component at an adjustable operating position along the axial direction.

The locking device includes, for example, a locking mechanism made up of latching, tensioning or clamping devices.

The fixing device can prevent external influences, for example vibrations, from changing an operating position of the first measurement component in an undesired manner.

The locking device can fix the measuring component in such a way that the locking device restricts the movement of the first measuring component along the axial direction, wherein the locking device allows a new operating position of the first measuring component to be set along the axial direction.

In some further exemplary embodiments of the distance measuring device, this also includes a stop on the first and/or second measuring component. The stop is designed to move the first measurement component to an operating position along the axial direction with the second measurement component.

The stop is designed in one piece with the first and/or second measuring component, for example.

In some further exemplary embodiments, the stop is designed to break at a predetermined breaking point when the piston is first disengaged.

The first measuring component can thus be positively connected to the second measuring component by means of the stop in order to set the operating position of the first measuring component when installing the displacement measuring device, and can be released again using the predetermined breaking point.

In some further exemplary embodiments, the stop is designed to move the first measurement component into the operating position counter to an axial disengagement direction of the piston.

This allows the first or second sensing component coupled to the piston to move freely in the disengagement direction of the piston.

In some further exemplary embodiments, the stop is designed to readjust the operating position of the first measuring component during operation of the displacement measuring device.

An adjusting device, for example a stop on the first and/or second measuring component, can readjust the first measuring component during operation of the displacement measuring device. The effects of a displacement of the piston counter to the axial disengagement direction, for example due to wear, can therefore be reduced on the measuring path to be provided.

In some further exemplary embodiments, the fixing device comprises a friction lining.

The friction lining can be used to fix the first measurement component by adhesion, such as a guide. Coefficients of friction of the friction lining can be low enough to adjust the operating position of the first measurement component along the axial direction using a compressive force of the piston. The coefficients of friction of the friction lining can be high enough to ensure locking during operation.

In some further exemplary embodiments, the fixing device comprises latching elements.

The locking elements can be used for an alternative or additional locking.

In some further exemplary embodiments, the first or second measurement component comprises a magnet and the respective other measurement component comprises a magnetic field sensor.

According to a second aspect, the present invention relates to a release system for actuating a clutch. The release system includes a piston that can be moved in an axial direction relative to a cylinder and a displacement measuring device. The path measuring device comprises a first measuring component and a second measuring component, which form a measuring system for measuring a position of the piston indicative of the relative position of the first and the second measuring component to one another. The first sensing component is coupled to one of the piston and cylinder parts. The second sensing component is coupled to the other of the piston and cylinder parts. The first measuring component is movable along the axial direction in relation to the part made up of a piston and cylinder.

The release system can in particular be a pneumatic, concentric release system (pneumatic central release).

In some further exemplary embodiments, the first or the second measuring component is designed as a magnet and the respective other measuring component is designed as a magnetic field sensor, with the magnetic field sensor outputting a control signal for valve control in response to the relative position.

The clutch is a friction clutch, for example, which is actuated by the valve control of the piston.

Such a friction clutch can be used in particular in commercial vehicles, passenger cars or other ground-based vehicles.

Further exemplary embodiments of the release system can include various exemplary embodiments of the displacement measuring device described above.

• 1 ein Ausrücksystem mit einer Wegmessvorrichtung;
• 2 ein erstes Ausführungsbeispiel der Wegmessvorrichtung mit Rastelementen;
• 3a das erste Ausführungsbeispiel der Wegmessvorrichtung in einer Seitenansicht, vor einer ersten Betätigung des Ausrücksystems;
• 3b das erste Ausführungsbeispiel der Wegmessvorrichtung in der Seitenansicht, nach der ersten Betätigung des Ausrücksystems;
• 4 ein zweites Ausführungsbeispiel der Wegmessvorrichtung mit Reibbelag;
• 5 das zweite Ausführungsbeispiel der Wegmessvorrichtung in einer Seitenansicht.

A few examples of exemplary embodiments of the invention are explained in more detail below with reference to the attached figures, merely by way of example. Show it:

• 1 a release system with a displacement measuring device;
• 2 a first embodiment of the displacement measuring device with latching elements;
• 3a the first exemplary embodiment of the distance measuring device in a side view, before a first actuation of the release system;
• 3b the first embodiment of the distance measuring device in the side view, after the first actuation of the release system;
• 4 a second embodiment of the displacement measuring device with friction lining;
• 5 the second embodiment of the distance measuring device in a side view.

Various exemplary embodiments will now be described in more detail and with reference to the accompanying figures.

Although example embodiments can be modified and altered in various ways, example embodiments are illustrated in the figures and are described in detail herein. It should be understood, however, that example embodiments are not intended to be limited to the precise forms disclosed, but rather that example embodiments are intended to cover all functional and/or structural modifications, equivalents, and alternatives falling within the scope of the invention.

In the 1 a conventional, concentric release system 100 is shown in longitudinal section. The release system 100 includes a ring cylinder 105, which surrounds a movement axis B ring-like. The ring cylinder 105 is firmly attached to a holding plate 110 which, for example, firmly connects the release system 100 to a frame of a vehicle.

A piston 115 likewise ring-like surrounding the axis of movement B, designed here as a ring piston, engages between an inner circumferential wall 120 and an outer circumferential wall 125 of the ring cylinder 105 . The piston 115 is sealed in a fluid-tight manner with respect to the inner circumferential wall 120 and the outer circumferential wall 125 via a plurality of sealing elements 130 . In relation to the ring cylinder 105, the piston 115 is movably guided in the movement axis B via guide bands 135.

The piston 115 and the ring cylinder 105 enclose a working space 140. The working space 140 can be filled with a pressure medium, here for example a pneumatic fluid. Fluid can be introduced into the working chamber 140 via a connection (not shown) in order to increase a fluid pressure in the working chamber 140 . A force results from the fluid pressure, which moves the piston 115 in an axial movement direction A relative to the ring cylinder 105 . Such a movement of the piston 115 is transmitted via a clutch release bearing 145, which is arranged on the piston 115, to a mechanical force accumulator, not shown here, for example a diaphragm spring. As a result, the energy accumulator reduces a compressive force on a pressure plate of a friction clutch and thus releases a transmission.

A biasing spring 150 is arranged concentrically to the movement axis B and provides a bias on the piston 115 against the axial direction A ready.

The release system 100 also includes a conventional position measuring device 155 for measuring a position of the piston 115 along the axial direction A. The release system 100 can be actuated automatically, with the position measuring device 155 providing a control signal for valve control of pressure valves at the connection of the working chamber 140.

The displacement measuring device 155 comprises a first measuring component, here a sensor 165, fastened in a housing 160, and a second measuring component, here a signal generator 170. The sensor 165, for example a magnetic field sensor, and the signal generator 170, for example a magnet, are operatively connected in such a way that that the sensor 165 can detect a signal, for example a magnetic field, from the signal transmitter 170 and can thus conclude a position of the sensor 165 relative to the signal transmitter 170 . A change in the position of magnet 170 in turn leads to a change in the magnetic flux density in sensor 165, as a result of which the position of magnet 170 and thus the release system can be inferred. The sensor 165 can be designed, for example, as at least one Hall sensor, magnetoresistive sensor or PLDC sensor (permanent magnetic linear contactless displacement).

The sensor 165 is fixed in the conventional displacement measuring device 155 within the housing 160 in a fixed operating position. The housing 160 is firmly connected to the ring cylinder 105 via the retaining plate 110 . The signal generator 170 is enclosed in a holder 185 which is firmly coupled to the piston 115 via a holding element 190 which is offset radially with respect to the piston 115 and thus follows a movement of the piston 115 in the axial direction A.

During a disengagement process, the signal generator 170 moves past the sensor 165 in a radially offset manner in a first guide 175 to which the sensor 165 is fastened. The sensor 165 detects the position of the sensor 165 relative to the signal transmitter 170, the relative position indicating a position of the piston 115 in the axial direction A.

In order for the sensor 165 to be able to continuously detect the signal generator 170 during the disengagement process, a sufficiently large measuring path 195 must be kept available in the sensor 165. In addition to a release travel of usually 14 mm (millimetres), measuring travel 195 also includes a wear travel of 13 mm and installation tolerances of a further 13 mm. In addition, the tolerance fluctuation between the sensor and target (e.g. magnet) is relatively large due to internal wear in the clutch actuation system and effects from a combustion engine (wobbling). As a result, only a few sensor technologies come into question for a sensor with a conventional structure. The large measurement length means that Hall sensors, for example, can only cover the entire measurement path (195) as a cascade. Such a long measuring path 195 requires a complex construction of the sensor 165. With the following exemplary embodiments, it is therefore necessary to shorten the measuring path 195.

It is therefore the aim of the present invention to shorten the measuring path in such a way that a more economical sensor system can be used. The approach is an adjustment that either only compensates for the tolerances or compensates for the tolerances and clutch wear, so that the measurement path can be reduced by 1/3 to 2/3.

2 shows an internal structure of a distance measuring device 255 according to the invention according to a first embodiment. The displacement measuring device 255 can replace the conventional displacement measuring device 155 in the release system 100 .

The housing 160 (not shown here) for the first measuring component (e.g. sensor 165) comprises a second guide 200 which is fixedly connected to the housing 160. The guide 200 comprises grooves 210, into which wing-shaped guide elements 220 which are attached laterally to the sensor 165 engage in a form-fitting manner. As a result, the sensor 165 is movable along the axial direction A within the housing 160 .

The guide elements 220 include leaf springs 230 which can engage in latching elements 240 mounted on the grooves 210 . The latching elements 240 are designed as prongs 260 when viewed from a line 250 , ie in cross section. A coil spring 270 connected to a rear wall of the guide 200 is configured to urge the leaf springs 230 against one of the tines 260. As shown in FIG. The tines 260 have a sawtooth shape.

A combination of the latching elements 240, the leaf springs 230 and the coil spring 270 can be seen as an exemplary embodiment of a locking device which fixes the sensor 165 at an adjustable operating position in the guide 200 within the housing 160 along the axial direction A. In this case, however, the sensor 165 remains movable counter to the axial direction A, provided that a spring force of the helical spring 270 is overcome. In other words, the sensor 165 can be moved into the guide 200, for example when the displacement measuring device 155 is installed, but cannot be moved out. This allows the sensor 165 to be placed in a desired operative position within the guide 200 but not move within the guide 200 in an undesired manner.

The sensor 165 is provided with a bulge 280 on an underside. A stop corresponding to the bulge 280 , designed here as a pin 290 , is fastened to an upper side of the holder 185 of the signal generator 170 . In this way, the sensor 165 can be connected to the signal generator 170 via a positive fit between the bulge 280 and the pin 290, for example before the displacement measuring device 100 is installed.

As a result, a relative position of the signal generator 170 to the sensor 165 is fixed for an initial point in time.

3a shows a side view of the sensor 165 and the holder 185 for the first exemplary embodiment before a first actuation of the release system 100. The sensor 165 and the holder 185 are connected to one another via the pin 290. FIG. The relative position of signal generator 170 to sensor 165 is thus fixed when release system 100 is installed. The pin 290 serves as a transport lock.

In the first exemplary embodiment, the measuring path 195 to be provided comprises a release path 300 of 14 mm and a wear path 310 of 13 mm. According to the first exemplary embodiment, additional paths due to installation tolerances do not have to be reserved.

3b shows a side view of the sensor 165 and the holder 185 according to the first embodiment, after the first actuation of the release system 100. The holder 185 of the signal generator 170 moves with the piston 115 in the axial direction A relative to the sensor 165, whose axial movement via the locking device Is blocked. The pin 290 breaks at a predetermined breaking point 320. The holder 185 can thus move freely with the piston 115 during all further disengagement processes.

When wear occurs on a friction clutch, the piston 115 can slide relative to the cylinder 105 along the axial direction A. When the clutch is pulled, the piston 115 can be displaced in relation to the cylinder 105 counter to the axial disengagement direction A of the piston 115 as a result of wear on the friction clutch. When the clutch is pressed, the piston 115 can be displaced in relation to the cylinder 105 in the axial disengagement direction A of the piston 115 as a result of wear on the friction clutch.

In other exemplary embodiments, the holder 185 can have a stop block 330 in addition to the pin 290 with the predetermined breaking point 320, with which the sensor 165 can be readjusted during operation of the displacement measuring device 255, for example in order to compensate for a wear displacement 310 in the measurement displacement 195. If wear occurs in release system 100, stop block 330 can move sensor 165 within guide 200 into a new operating position counter to an axial release direction A of piston 115. A wear path 310 to be maintained in the measurement path 195 and a path to be maintained due to installation tolerances are thus omitted. The measurement path 195 can thus be limited to just the disengagement path 300, which can significantly simplify the construction of the sensor 165.

In other exemplary embodiments, a stop block 330 can be configured to adjust an operating position of sensor 165 within guide 200 during operation of displacement measuring device 255 in an axial disengagement direction A of piston 115 in the event of a pulled clutch. For this purpose, the stop block 330 can be attached to a different position of the holder 185 , for example in such a way that the stop block 330 is in contact with a rear side 340 of the sensor 165 .

4 shows an internal structure of the distance measuring device 255 according to a second embodiment. The housing 160 (not shown here) includes a guide 200 with grooves 210 in which the sensor 165 engages in a form-fitting manner. The outer walls of the sensor 165 and the inner walls of the guide 200 comprise a friction lining 400. The friction lining 400 serves as a locking device and prevents unwanted displacement of the sensor 165 in the guide 200 through frictional engagement 165 in the guide 200 when an operating position of the sensor 165 is to be adjusted. The operating position of the sensor 165 can be adjusted, for example, in order to avoid displacement of the sensor 165 with respect to the piston 115 due to wear. The operating position of the sensor 165 can be adjusted, for example by a stop coupled to the piston 115 .

The sensor 165 has a stop on its underside, designed here as a stop block 410 . The stop block 410 can, for example, adjust an operating position of the sensor 165 within the guide 200 during operation of the displacement measuring device 255 .

5 shows a side view of the sensor 165 and the holder 185 according to the second embodiment. The holder 185 of the signal generator 170 rests against the stop block 410 of the sensor 165 . When the path measuring device 155 is installed, the holder 185 presses the sensor 165 into an operating position in the guide 200. A relative position of the signal generator 170 to the sensor 165 is thus fixed.

When release system 100 is actuated, bracket 185 moves in axial direction A away from stop block 410 . After actuation, the bracket 185 moves back until it abuts the stop block 410 again.

If wear occurs in the release system 100, the holder 185 moves counter to the axial direction A and thus presses the sensor 165 further into the guide 200 via the stop block 410 up to a new operating position.

In the second exemplary embodiment, the measuring path 195 includes a disengagement path 300 of 14 mm. Neither wear path 310 nor installation tolerances have to be taken into account for measuring path 195.

In other exemplary embodiments according to the invention, the first measurement component can be the signal transmitter 170 and the second measurement component can be the sensor 165 .

In other exemplary embodiments according to the invention, the position of sensor 165 and signal transmitter 170 can be swapped. Thus, the sensor 165 can be coupled to the piston 115 and the signal generator 170 to the ring cylinder 105 .

In this variant, instead of the sensor 165, the signal transmitter 170 can be guided with limited mobility in the axial direction A relative to the ring cylinder 105 via a locking device.

The locking devices used in the two exemplary embodiments shown, designed as latching elements 240 or as friction linings 400, and stops, designed as a pin 290 or as a stop block 410, can be combined differently in further exemplary embodiments.

1. 1. Ausgleich der Toleranzen durch einmalige Einstellung beim Einbau. Hierbei ist weiterhin ein Sensorweg für den Betätigungshub sowie den Verschleißweg vorgehalten, beispielsweise 25 mm.
2. 2. Ausgleich der Toleranzen und Kupplungsverschleiß. Der Sensorweg beschränkt sich hierbei auf den Betätigungshub, beispielsweise 13 mm.

In summary, the present invention therefore proposes to design one of the sensor components, for example the sensor or the signal generator 170, to be axially movable to a limited extent and to provide a wear-dependent position by means of a locking device. This enables the following advantages:

1. 1. Compensation of the tolerances through a one-off setting during installation. A sensor path for the actuation stroke and the wear path is also provided, for example 25 mm.
2. 2. Compensation for tolerances and clutch wear. The sensor travel is limited to the actuation stroke, for example 13 mm.

For example, the sensor is housed in a housing element that has friction surfaces. In the initial state, the sensor is mounted as far as possible extended. If the piston is now mounted with the magnet holder or installed in the vehicle, the magnet holder searches for its axial position and presses the sensor over the stop in the direction of the gearbox. The disengagement movement takes place in the opposite direction, so that the sensor does not change its position. If there is now wear on the clutch, the piston including the magnet slowly moves in the direction of the gearbox and the sensor is pushed backwards again via the stop. This means that only the actuation path has to be kept available in the sensor.

Alternatively, the sensor position can be adjusted once. During installation, the sensor is pushed into the correct position by a stop on the magnet holder. As a result, the assembly tolerances are already compensated and no longer have to be maintained, which already significantly reduces the sensor travel.

The sensor snaps into the correct axial position and remains there for the life of the release system. The stop is released via a predetermined breaking point on the magnet holder, so that the magnet holder can move freely in relation to the sensor without causing a relative force on the sensor. This unique setting does not have to work automatically, but can also be produced by assembly intelligence. This means that a machine can adjust the position of the sensor along the axial direction if, for example, the assembly tolerances are known and the final axial position of the sensor is only fixed when the overall system is installed (big data, i.e. all tolerances are known).

The following claims are hereby incorporated into the Detailed Description, with each claim being able to stand on its own as a separate example. It should also be noted that although a dependent claim in the claims refers to a particular combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject-matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed, unless it is stated in individual cases that a specific combination is not intended. Furthermore, features of a claim are also intended to be included for any other independent claim, even if that claim is not directly defined as dependent on that other independent claim.

Reference List

100

release system

105

ring cylinder

110

Retaining plate

115

Pistons

120

inner wall

125

outer wall

130

sealing element

135

guide band

140

working space

145

release bearing

150

bias spring

155

Conventional displacement measuring device

160

Housing

165

First measuring component/sensor

170

Second measuring component/signal transmitter

175

First Guide

185

bracket

190

holding element

195

measuring path

200

Second Guide

210

groove

220

guide element

230

leaf spring

240

locking element

250

line

255

Displacement measuring device according to the invention

260

Pink

270

coil spring

280

bulge

290

Pen

300

way out

310

wear path

320

predetermined breaking point

330

stop block

340

back

400

friction lining

410

stop block

A

Axial direction of movement

B

motion axis

Claims (10)

Displacement measuring device (255) for measuring a position of a piston (115) relative to a cylinder (105) along an axial direction (A), comprising: a first measuring component (165) and a second measuring component (170) forming a measuring system for measuring a position of the piston (115) indicative of a relative position of the first and second measuring components (165, 170) to one another; the first sensing component (165) being coupled to one of the piston (115) and cylinder (105); the second sensing component (170) being coupled to the other of the piston (115) and cylinder (105); wherein the first measuring component (170) is designed to be movable along the axial direction (A) with respect to the one part consisting of the piston (115) and the cylinder (105). Displacement measuring device (255) according to claim 1 , further comprising a fixing device, which is designed to fix the first measurement component (165) at an adjustable operating position along the axial direction (A). Displacement measuring device (255) according to one of the preceding claims, further comprising a stop on the first and/or second measuring component (165, 170), which is designed to move the first measuring component (165) to an operating position with the second measuring component (170). to move in the axial direction (A). Displacement measuring device (255) according to claim 3 , wherein the stop is designed to break at a predetermined breaking point (320) during the first disengagement process of the piston (115). Displacement measuring device (255) according to claim 3 or 4 , The stop being designed to move the first measurement component (165) into the operating position counter to an axial disengagement direction (A) of the piston (115). Displacement measuring device (255) according to one of claims 3 until 5 , wherein the stop is designed to readjust the operating position of the first measuring component (165) during operation of the displacement measuring device (255). Displacement measuring device (255) according to one of claims 2 until 6 , wherein the locking device comprises a friction lining (400). Displacement measuring device (255) according to one of claims 2 until 7 , wherein the locking device comprises latching elements (240). Displacement measuring device (255) according to one of the preceding claims, wherein the first or the second measuring component (165, 170) comprises a signal generator, in particular a magnet, and the respective other measuring component comprises a signal receiver, in particular a magnetic field sensor. Release system (100) for actuating a clutch, comprising: a piston (115) movable in an axial direction (A) relative to a cylinder (105); and a displacement measuring device (255) comprising: a first measuring component (165) and a second measuring component (170) forming a measuring system for measuring a position of the piston (115) indicative of a relative position of the first and second measuring components (165, 170) to one another; the first sensing component (165) being coupled to one of the piston (115) and cylinder (105); the second sensing component (170) being coupled to the other of the piston (115) and cylinder (105); wherein the first measuring component (170) is designed to be movable along the axial direction (A) with respect to the one part consisting of the piston (115) and the cylinder (105).

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