DE102020201277A1 - Release system and displacement measuring device for measuring a position of a piston in an axial direction - Google Patents

Abstract

The present invention relates to a displacement measuring device (100) for measuring a position of a piston in an axial direction (191). The displacement measuring device (100) comprises a first measuring component (110) coupled to the piston. The displacement measuring device (100) further comprises a second measuring component (120), offset in a circumferential direction (193) relative to the first measuring component (110), for measuring a position of the first measuring component (110) relative to the second measuring component (120), which is characteristic of the Position of the piston is. The first measurement component (110) can be displaced in the axial direction (191) with respect to the second measurement component (120). The first measuring component (191) is secured against deflection in the circumferential direction (193) and can be moved in a radial direction (192).

Description

The present invention relates to a release system, in particular for actuating a clutch, and to a travel measuring device for measuring a position of a piston in an axial direction, in particular in a release system.

In particular, pneumatically actuated, concentric release systems have established themselves as the standard in commercial vehicles for actuating a clutch. Due to a higher functional integration compared to other release systems and a more compact design in combination with the use of existing peripherals, such as compressed air, such systems offer several advantages.

Such a release system requires information about a position of a piston that can be moved for actuating the clutch, for example for control purposes. Distance measuring devices are known which are based on the fact that a signal transmitter or a sensor is coupled to the piston of the release system.

In known release systems, the signal transmitter and the sensor are arranged in a radial direction to one another. Due to interfering influences, such as circumferential misalignments of the piston, the signal transmitter can be deflected in the axial direction with respect to the sensor in known displacement measuring devices. As a result, in particular a signal quality of the known displacement measuring devices can be impaired.

In addition, the circumferential misalignments of the piston can lead to undesired wear in known displacement measuring devices.

The document DE 10 2014 116 561 A1 describes a clutch bearing with a target element movable in translation along an axis and a detector for detecting a position of the target element which is representative of a position of an actuating element for actuating a clutch. The target element is arranged offset angularly to the detector with respect to the axis.

As a result, a space requirement can be reduced along a radial direction.

No concept emerges from the document which is suitable for reducing wear on the clutch bearing and / or impairments of the signal quality which result from the disturbing influences of the piston.

The document DE 10 2018 113 397 B3 describes a slave cylinder for a clutch actuator of a motor vehicle. The slave cylinder comprises a piston that can be displaced in its longitudinal axis and an actuating bearing that is fixedly coupled to the piston displacement, as well as a sensor device designed to detect the position of the piston along its displacement path. The sensor device comprises a sensor and a transducer part which can be detected by the latter and which is coupled to the actuating bearing via a carrier in a non-shiftable manner. The carrier is guided on a guide rail. The carrier has a loop area running on the guide rail with a through hole axially penetrating the loop area.

In the case of circumferential misalignments or if the piston wobbles, constraining forces can act on the guide rail in a radial direction. Wear caused by this can limit the service life of the clutch actuation device.

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

This object can be achieved with the aid 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 in an axial direction. The displacement measuring device comprises a first measuring component coupled to the piston. Furthermore, the displacement measuring device comprises a second measuring component, which is arranged offset in a circumferential direction relative to the first measuring component, for measuring a position of the first measuring component relative to the second measuring component, which is characteristic of the position of the piston. The first measurement component is displaceable in the axial direction with respect to the second measurement component. The first measuring component is secured against deflection in the circumferential direction and can be moved in a radial direction.

The release system is designed, for example, to actuate a clutch by moving the piston in the axial direction. In the case of a pneumatic release system, the movement of the piston can be controlled, for example, by controlling a pressure.

A transfer function of the clutch is therefore dependent, for example, on the position of the piston in the axial direction.

The axial direction relates, for example, to an axis of rotation of the clutch and / or the release system.

The first measurement component can be connected to the piston in a non-displaceable manner, so that the first measurement component follows a movement of the piston in the axial direction. The movement of the piston can therefore be converted into a movement of the first measurement component in the axial direction, the first measurement component being displaced with respect to the second measurement component. The first measurement component is coupled to the piston by a screw connection, for example.

The second measuring component is, for example, fixedly arranged on a housing of the release system.

The circumferential direction relates, for example, to a circumference of the piston or a direction running tangentially to the circumference.

The first measuring component can be mechanically secured against the deflection in the circumferential direction, so that a distance between the first and the second component in the circumferential direction is constant within the scope of a movement play.

As a result, variations in the distance, which for example lead to measurement errors and / or a deterioration in signal quality when measuring the position of the first measurement component in relation to the second measurement component, between the first and second measurement components can be avoided or at least limited or reduced to a degree of play

The deflection includes, for example, a displacement along the circumferential direction and / or an intrinsic rotation of the first measurement component about an axis parallel to the axial direction.

Disturbing influences of the piston can manifest themselves in particular in a deflection of the first measuring component in the radial direction. Since the first measurement component can be moved in the radial direction, the first measurement component can move in the radial direction in the event of interference from the piston.

Constraint forces that occur when the piston is disturbed, which arise, for example, when the first measuring component is supported in the radial direction, can thus be avoided and wear associated therewith can at least be reduced.

For this purpose, the first measurement component can be movable in the radial direction at least in a region of maximum deflection, which is possible for the first measurement component in the event of interference from the piston.

In some exemplary embodiments, the displacement measuring device further comprises a carrier element which is secured against deflection in the circumferential direction. The first measurement component is coupled to the piston via the carrier element, for example.

The carrier element can be adapted so that it can be coupled to the piston by means of a screw connection, for example. Furthermore, the carrier element can have a pocket which is used to hold the first measurement component.

Coupling the first measuring component via the carrier element can be technically simpler and more cost-effective than direct coupling of the first measuring component to the piston, since the carrier element, for example, compared to the first measuring component, is manufactured from a plastic using an original molding process and is thus adapted more cost-effectively for coupling to the piston can.

In some exemplary embodiments, the displacement measuring device further comprises a guide, the guide being designed to support the carrier element for securing the carrier element against deflection in a first circumferential direction and in a second circumferential direction opposite to the first circumferential direction.

The guide comprises, for example, two support surfaces, one of which is arranged in the first or in the second circumferential direction adjacent to the carrier element. To secure the carrier element against deflection in the first or in the second circumferential direction, the first and the second support surface come into contact with, for example, one or both of the support surfaces.

Analogously to the circumferential direction, the first and the second circumferential direction relate, for example, to the circumference of the piston or a tangent of the circumference.

The securing of the carrier element in the first and second circumferential directions can alternatively be implemented in connection with a dovetail guide or a guide comparable to this, which is coupled to the carrier element in such a way that the carrier element can be moved in the radial direction.

In some exemplary embodiments of the displacement measuring device, the carrier element comprises a Plant section which is designed for a plant with the second measuring component.

The circumferential direction can relate to the first or the second circumferential direction.

The contact section is arranged on the carrier element in the circumferential direction, for example.

As a result of the contact between the carrier element and the second measuring component, the position of the carrier element with respect to the second measuring component can be kept constant in the circumferential direction within the scope of an intended play of movement.

In some exemplary embodiments, the displacement measuring device furthermore comprises an adjustment unit which is designed to hold the second measuring component in contact with the contact section.

Wear-related abrasion of the carrier element in the guide can lead to a displacement of the carrier element within the guide in the circumferential direction. The shift occurs, for example, in the first or in the second circumferential direction.

The adjustment unit comprises, for example, a spring or an actuating element (for example a servomotor) which presses the second measuring component in the circumferential direction against the contact section in order to compensate for the (wear-related) displacement of the carrier element.

As a result, it can be ensured, for example over the life of the displacement measuring device, that the position of the carrier element with respect to the second measuring component is constant in the circumferential direction within the scope of a movement game.

In some exemplary embodiments of the displacement measuring device, the adjustment unit comprises a helical spring which is designed to press the second measuring component against the contact section in order to keep the second measuring component in contact with the contact section.

The helical spring can be used instead of the named actuating unit and can represent a more cost-effective alternative to the actuating unit, for example because of the lower manufacturing costs compared to the actuating unit.

In some exemplary embodiments of the displacement measuring device, the carrier element comprises a first contact section which is designed to support the second measuring component against a deflection of the second measuring component relative to the carrier element in the first circumferential direction. Furthermore, the carrier element can comprise a second contact section which is designed to support the second measuring component against a deflection of the second measuring component with respect to the carrier element in the second circumferential direction.

The first and the second contact section are, for example, each arranged in the first circumferential direction or in the second circumferential direction adjacent to the second measuring component. Thus, the second measuring component can come to rest flat against the first or the second contact section in order to support the second measuring component against the deflection with respect to the carrier element or the first measuring component.

The second measuring component is thus secured against any deflection in the circumferential direction, for example.

In some exemplary embodiments of the displacement measuring device, the first measuring component comprises a magnet. The second measurement component can comprise a sensor which is designed to measure the position of the first measurement component with respect to the second measurement component on the basis of a local magnetic field of the magnet.

The magnet is, for example, a permanent magnet or, alternatively, an electromagnet.

The sensor is, for example, a magnetic field sensor which is designed to detect a magnetic flux density and / or a magnetic field strength of the local magnetic field.

The local magnetic field relates, for example, to a magnetic field located in a measuring range of the sensor.

On the basis of the magnetic flux density or the magnetic field strength, a distance between the sensor and the magnet, and thus the position of the magnet relative to the sensor in the axial direction, can be determined.

According to a second aspect, the present invention relates to a release system, in particular for actuating a clutch.

The release system can in particular be a pneumatic release system which is designed to operate a clutch, such as a friction clutch of a vehicle.

The displacement measuring device is used, for example, to measure the position of the piston in the axial direction. The position of the piston in the axial direction can be used, for example, as a control variable for controlling the release system.

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

• 1a schematisch eine Wegmessvorrichtung in einer axialen Richtung;
• 1b schematisch die Wegmessvorrichtung in einer Umfangsrichtung;
• 2a ein Ausführungsbeispiel der Wegmessvorrichtung in einer ersten Schrägansicht; und
• 2b das Ausführungsbeispiel der Wegmessvorrichtung in einer zweiten Schrägansicht.

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

• 1a schematically a displacement measuring device in an axial direction;
• 1b schematically the displacement measuring device in a circumferential direction;
• 2a an embodiment of the displacement measuring device in a first oblique view; and
• 2 B the embodiment of the displacement measuring device in a second oblique view.

Various embodiments will now be described in more detail with reference to the accompanying drawings, in which some embodiments are shown.

Although exemplary embodiments can be modified and changed in various ways, exemplary embodiments are shown in the figures as examples and are described in detail herein. It should be made clear, however, that the intention is not to restrict exemplary embodiments to the respectively disclosed forms, but rather that exemplary embodiments are intended to cover all functional and / or structural modifications, equivalents and alternatives that are within the scope of the invention.

In known displacement measuring devices, in disengagement systems, for example, due to circumferential misalignments of a piston, the signal transmitter can be deflected in relation to a sensor. As a result, in particular a signal quality of the known displacement measuring devices can be impaired.

In addition, the circumferential misalignments of the piston can lead to undesired wear in known displacement measuring devices.

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

1a and 1b show schematically a displacement measuring device 100 for measuring a position of a piston (not shown) in an axial direction 191 . The axial direction 191 runs, for example, perpendicular to a radial direction 192 and a circumferential direction 193 .

The position measuring device 100 comprises a first measurement component coupled to the piston 110 and a second measurement component 120 which in the circumferential direction 193 is arranged offset to the first measuring component. The second measuring component 120 is for measuring a position of the first measuring component 110 compared to the second measuring component 120 educated.

The first measuring component 110 is coupled to the piston in such a way that movements of the piston result in movement of the first measurement component 110 can be transmitted in the axial direction. Hence the position of the first measuring component 110 compared to the second component 120 indicative of the position of the piston.

The first measuring component is used for this 110 compared to the second measuring component 120 in the axial direction 191 movable.

In addition, is the first measuring component 110 against deflection in the circumferential direction 193 secured. In the in 1a and 1b The example shown is the first sample component 110 for example on a carrier element 130 arranged, which against deflection in the circumferential direction 193 is secured. The carrier element is for example by a guide 140 so secured.

The leadership 140 engages around the carrier element 130 for this on two in the circumferential direction 193 aligned sides of the carrier element 130 .

In the radial direction 192 lets the lead 140 at least a maximum possible deflection due to interfering influences of the piston 132 the first sample component 110 in the radial direction 192 outwards and inwards too.

As in 1b shown, the carrier element 130 if the piston wobbles or rotates in a misalignment with respect to the second measuring component 120 in the radial direction 192 tilt or be deflected.

As shown, the first measurement component 110 be arranged relative to the piston so that the first measurement component 110 up to the maximum possible deflection due to interfering influences of the piston 132 in the radial direction 192 for example within a measuring range or measuring field (not shown) of the second component 120 emotional.

Optionally, the first measuring component 110 against deflection in the radial direction 192 beyond the measuring field through a stop for the carrier element 130 be secured.

Alternatively, the measuring field of the second measuring component 120 in the radial direction 192 to the maximum possible deflection 132 the first component 110 be adjusted.

The first measuring component 110 is designed, for example, as a signal transmitter, in particular as a magnet.

The second measuring component 120 can comprise a sensor, such as a magnetic field sensor, or in particular be designed as such. The magnetic field sensor

In some exemplary embodiments of the displacement measuring device 100 can use the first sample component 110 such a sensor and the second measuring component 120 comprise a signal transmitter or magnet, or be designed as such.

For reasons of cost, it can make sense that the first measuring component 110 the magnet and the second measuring component 120 comprises the corresponding sensor, since a connection for supplying the sensor with a movable sensor can be technically more complex than with a permanently arranged sensor.

Due to the arrangement described above, one layer of the magnet has 110 for example (only) in the context of a movement game within the guide influence on a distance in the circumferential direction 193 between the magnet 110 and the sensor 120 .

This can prevent measurement errors resulting from a variation in the distance in the circumferential direction between the magnet 110 and the sensor 120 result, be reduced.

The leadership 140 , which can also be referred to as "anti-rotation device", can also be used to tangentially support the carrier element 130 in the circumferential direction 193 serve, while movement is not further restricted in some exemplary embodiments.

As the carrier element 130 within the leadership 140 in the axial direction 191 can move is, for example, a guide of the carrier element 130 with respect to the circumferential direction 193 given.

Deflections of the magnet 110 in the radial direction 192 can be included to a certain extent as a measurement error in a measurement of the position of the piston, which is, for example, sufficiently small to ensure control of the clutch.

The carrier element 130 and / or the leadership 140 are made of a plastic, for example. For manufacturing the carrier element 130 and / or leadership 140 An injection molding process that is more cost-effective than milling processes can therefore be suitable.

2a and 2 B show an embodiment of the displacement measuring device in a three-dimensional overall view.

In contrast to the previously shown embodiment, the carrier element 130 a first plant section 134-1 and a second abutment section 134-2 on which a recess for receiving the sensor 120 in a first circumferential direction 193-1 , or in a second circumferential direction 193-2 limit. The recess extends in a rectangular cross section in the axial direction 191 through the carrier element 130 .

The first and second circumferential directions 193-1 and 193-2 refer to opposite along the circumferential direction 193 trending directions. Below the circumferential direction 193 can be the first circumferential direction 193-1 and / or the second circumferential direction 193-2 be understood.

The first and the second plant section 134-1 and 134-2 can be used as a guide or to protect against deflection of the sensor 120 compared to the carrier element 130 and the magnet 110 in the first circumferential direction 193-1 , or in the second circumferential direction 193-2 as a stop for contact with the sensor 120 serve.

The sensor 120 can have a play in the circumferential direction 193 between the first and the second plant section 134-1 and 134-2 exhibit.

The leadership 140 and / or the carrier element 130 can occur when the carrier element moves 130 rub against each other in the axial direction and are therefore subject to friction-related wear.

In particular in automotive applications, the carrier element 130 and the leadership 140 for example, due to a certain direction of rotation of a crankshaft either in the first Circumferential direction 134-1 or in the second circumferential direction 134-2 have greater wear due to friction than in a respective opposite circumferential direction.

Depending on this, the carrier element 130 hence a shift within the leadership 140 in one of the circumferential directions 134-1 or 134-2 Experienced.

The displacement of the carrier element 130 can be compensated for by an adjustment unit 136 to adjust the distance between the magnet 110 and the sensor 120 in the circumferential direction 193 when moving the carrier element 130 in the circumferential direction 193 keep constant.

The adjustment unit 136 is, for example, for connecting the sensor 120 to the leadership 140 formed and may comprise a coil spring.

In the present example, the adjustment unit 136 is designed, for example, as a helical spring, which the sensor 120 to the first section 134-1 or the second section of the system 134-2 presses. As a result, the helical spring 136 can put the sensor in contact with the first contact section 134-1 , or the second section of the system 134-2 and thus the distance between the magnet 110 and the sensor 120 in the circumferential direction 193 if the guide is worn 140 and / or the carrier element 130 keep constant.

Alternatively, the adjustment unit 136 can electronically adjust the sensor 120 effect. The readjustment can be regulated by an indicator (not shown here) such as, for example, a controlled variable which indicates wear.

The sensor can 120 be arranged so that the measuring field of the sensor 120 one of the circumferential directions 193-1 and 193-2 facing with the higher wear.

It can thereby be achieved that the distance in the circumferential direction increases as a result of wear 193 between the magnet 110 and the sensor 120 for example, is reduced within a tolerance range and limited by a stop in some exemplary embodiments. This can ensure that the distance is in the circumferential direction 193 between the magnet 110 and the sensor 120 does not fall below a critical value.

The adjustment can either be in the first circumferential direction 193-1 or in the second circumferential direction 193-2 respectively.

The leadership 140 can have holes 142 have which, for example, to connect the guide 140 to a housing (not shown) or a holding element (not shown) of the position measuring device 100 can serve. The holding element couples the position measuring device 100 for example with a chassis of a vehicle in automotive applications of the position measuring device 100 .

To reduce the installation space required in the radial direction 192 can connect the sensor 120 can be adapted in such a way that the adjustment unit 136, in contrast to the one in FIG 2a and 2 B embodiment shown in the axial direction 191 offset to the sensor 120 is arranged.

In addition, a supply line 122 of the sensor 120 be arranged so that the lead in the circumferential direction 193 instead of in the radial direction 192 from the sensor 120 gone off.

The aspects and features that are described together with one or more of the previously detailed examples and figures can also be combined with one or more of the other examples in order to replace an identical feature of the other example or to add the feature in the other example to introduce.

Furthermore, the following claims are hereby incorporated into the detailed description, where each claim can stand on its own as a separate example. While each claim may stand on its own as a separate example, it should be noted that although a dependent claim in the claims may refer to a particular combination with one or more other claims, other examples also combine the dependent claim with the subject matter of each other dependent or independent claims. Such combinations are explicitly suggested here unless it is indicated that a particular 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 made directly dependent on the independent claim.

List of reference symbols

100

Position measuring device

110

first measuring component / magnet

120

second measuring component / sensor

130

Support element

132

maximum possible deflection of the first measuring component

134-1

first section

134-2

second plant section

140

guide

142

hole

191

axial direction

192

radial direction

193

Circumferential direction

193-1

first circumferential direction

193-2

second circumferential direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102014116561 A1 [0006]
• DE 102018113397 B3 [0009]

Claims (9)

Position measuring device (100) for measuring a position of a piston in an axial direction (191), comprising: a first measurement component (110) coupled to the piston; a second measuring component (120) arranged offset in a circumferential direction (193) relative to the first measuring component (110) for measuring a position of the first measuring component (110) with respect to the second measuring component (120), wherein the position of the first measuring component (110) relative to the second component (120) is indicative of the position of the piston, wherein the first measuring component (110) is displaceable in relation to the second measuring component (120) in the axial direction (191); wherein the first measuring component (110) is secured against deflection in the circumferential direction (193); and wherein the first measuring component (110) is movable in a radial direction (192). Distance measuring device (100) according to one of the preceding claims, further comprising a carrier element (130), wherein the first measuring component (110) is coupled to the piston via the carrier element (130); and wherein the carrier element (130) is secured against deflection in the circumferential direction (193). Distance measuring device (100) according to Claim 2 , further comprising: a guide (140), wherein the guide (140) is formed around the carrier element (130) for securing the carrier element (130) against deflection in a first circumferential direction (193-1) and one of the first circumferential direction (193-1) to support opposite second circumferential direction (193-2). Distance measuring device (100) according to Claim 2 , the carrier element (130) comprising: a contact section (134-1, 134-2) which is designed for contact with the second measuring component (120). Distance measuring device (100) according to Claim 4 , further comprising an adjustment unit (136) which is designed to hold the second measuring component (120) in contact with the contact section (134-1, 134-2). Distance measuring device (100) according to Claim 5 , wherein the adjustment unit (136) comprises a helical spring which is designed to press the second measuring component (120) against the contact section (134-1, 134-2) in order to connect the second measuring component (120) to the contact section (134-1, 134-2) to be kept in the system. Distance measuring device (100) according to Claim 3 , the carrier element (130) further comprising: a first contact section (134-1) which is designed to prevent the second measurement component (120) from deflecting the second measurement component (120) with respect to the carrier element (130) in the first circumferential direction (193 -1) support; and a second contact section (134-2) which is designed to support the second measuring component (120) against a deflection of the second measuring component (120) with respect to the carrier element (130) in the second circumferential direction (193-2). Distance measuring device (100) according to one of the preceding claims, wherein the first measuring component (110) comprises a magnet; and wherein the second measuring component (120) comprises a sensor which is designed to measure the position of the first measuring component (110) with respect to the second measuring component (120) on the basis of a local magnetic field of the magnet. Release system, in particular for actuating a clutch, comprising: a piston movable in an axial direction (191); a displacement measuring device (100) according to one of the preceding claims for measuring a position of the piston in the axial direction (191).

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