DE102020120625A1 - Concentric slave cylinder with position sensor - Google Patents

Abstract

The invention relates to a central release mechanism (1), in particular for a hydraulic release system (2) of a clutch system (3) of a motor vehicle (4), comprising a central release mechanism housing (5) with an annular central release mechanism piston chamber (6) in which a central release mechanism piston chamber (6) hydraulic fluid (7) that can be supplied, a central release piston (8) is accommodated so as to be axially movable, a sensor unit (9) being stationarily arranged on the central release housing (5), and a sensor body (12) in or on a carrier element coupled to the central release piston (8). (13) is arranged such that a linear offset of the central slave cylinder (8) causes a linear offset of the sensor body (12), the carrier element (13) having at least one magnetic element (15) which causes the carrier element (13) to have a magnetic force at least in the direction of the linear offset of the central release piston (8) relative to the central release piston (8) fixed and / or the Ze Central release piston (8) has at least one magnetic element (15) which fixes the carrier element (13) by magnetic force at least in the direction of the linear offset of the central release piston (8) relative to the central release piston (8).

Description

The invention relates to a central release mechanism, in particular for a hydraulic release system of a clutch system of a motor vehicle, comprising a central release mechanism housing with an annular central release mechanism piston chamber in which a central release mechanism piston is accommodated in an axially movable manner through hydraulic fluid that can be supplied to the central release mechanism piston chamber, with a sensor unit being stationarily arranged on the central release mechanism housing, and a Sensor body is arranged in or on a carrier element coupled to the central release piston that a linear displacement of the central release piston causes a linear displacement of the sensor body.

It is basically known from the prior art that concentric slave cylinders can have a position sensor for detecting the position of the central slave cylinder piston. EP1898111B1 describes, for example, a central release mechanism for hydraulic clutch actuation, which has a housing having a cylindrical through-bore and a tubular sleeve arranged concentrically inside the through-bore and fixed at one end centered to the housing, on which a ring piston that can be operatively connected to the clutch is guided in an axially displaceable manner the outer end of which has the inner ring of a release bearing attached, with a sensor for detecting the axial position of the annular piston relative to the housing being attached to the housing in a stationary manner, and with the sensor being assigned an axially displaceably guided magnet body which is attached to an annular body on the inner ring for entrainment is connected without play axially by the annular piston during its axial displacements; the magnet body is slidably guided at a constant distance from the sensor on the housing over its displacement path and engages with a guide shoe in a circumferential groove of the ring body without axial play but radially movable. Due to signs of wear, however, the axially play-free guidance, which is required for adequate measurement accuracy, cannot always be ensured with increasing service life.

It is the object of the present invention to at least partially overcome the disadvantages known from the prior art. It is in particular the object of the present invention to provide a solution by which the accuracy of the measurement of the position of a central slave cylinder piston can be improved. It is also the object of the present invention to provide a concentric slave cylinder that is particularly compact in terms of its radial structure.

This object is achieved by a central release mechanism, in particular for a hydraulic release system of a clutch system of a motor vehicle, comprising a central release mechanism housing with an annular central release mechanism piston chamber in which a central release mechanism piston is accommodated in an axially movable manner through a hydraulic fluid that can be supplied to the central release mechanism piston chamber, with a sensor unit being stationarily arranged on the central release mechanism housing, and a sensor body is arranged in or on a support element coupled to the central release piston in such a way that a linear offset of the central release piston causes a linear offset of the sensor body, the support element having at least one magnetic element which causes the support element to have a magnetic force at least in the direction of the linear offset of the central release piston fixed to the central release piston and/or the central release piston has at least one magnetic element which supports the carrier element ment fixed by magnetic force at least in the direction of the linear offset of the central slave cylinder relative to the central slave cylinder.

A central slave cylinder of this type is easy to produce and in particular allows a particularly precise determination of the axial position of the central slave cylinder, even as the service life and mechanical wear progress, by compensating for any axial play that may occur due to magnetic force. Thus, such a concentric slave cylinder can have significant advantages over prior art designs.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the set of claims, and particularly preferred configurations of the subject matter of the invention are described below.

Fully hydraulic clutch systems in motor vehicles can be equipped with a central slave cylinder, which is often also referred to as a concentric slave cylinder (CSC). This can in particular consist of an annular hydraulic central release cylinder with an integrated release bearing, which is preferably arranged in the clutch housing between the transmission and the clutch in the middle of the transmission input shaft, which means that the lever in the transmission bell housing, as used in arrangements with a conventional slave cylinder, can be omitted .

A hydraulic release system usually has a master cylinder that Master cylinder pressure generated via a hydraulic pressure line transmits to the slave cylinder.

Occasionally, the hydraulic pressure is also measured using a so-called Provided power packs, which consists of a hydraulic pump and acted upon by the hydraulic pump hydraulic pressure accumulator. In this case, a pressure chamber of the slave cylinder can also be pressurized hydraulically, for example, by a master cylinder that is controlled by a control unit by means of an electric motor, or by a hydraulic pump, optionally with the cooperation of a pressure accumulator. A so-called power pack can be used in an advantageous manner, which switches a plurality of pressure circuits, in particular, via a central hydraulic pump and corresponding valves.

The slave cylinder transmits the hydraulic pressure to a lever system, which can be formed by a plate spring, for example, by means of an axially displaceable piston and with the interposition of a clutch release bearing. The plate spring acts on a clutch pressure plate which is connected to a clutch housing in a rotationally fixed and axially displaceable manner and is braced against a pressure plate which is fixedly connected to the clutch housing. A clutch disc with a clutch lining is arranged between the pressure plate and the clutch pressure plate, which, depending on the tension between the pressure plate and the clutch pressure plate, form a frictional connection and close the friction clutch or open it when the frictional connection is removed.

A clutch system for motor vehicles has the function of switching the driving engine side in a drive train of a vehicle to couple or uncouple it from the transmission side and thus enable a gear change of the transmission while driving and thereby operate the driving engine in a preferred speed/torque range to be able to

A basic distinction is made between manually operated clutch systems and automatic clutch systems. In a manually operated clutch system, the clutch engagement and disengagement process is triggered and controlled manually by the driver, for example by muscle-operated actuation of a clutch pedal. In automatic clutch systems, this control and actuation is performed by an electronic controller and actuators, so that the driver no longer has to intervene to change gears while driving. As a result, automatic clutch systems usually do not have a clutch pedal.

For the purposes of this application, motor vehicles are land vehicles that are moved by machine power without being tied to railroad tracks. A motor vehicle can be selected, for example, from the group of passenger cars (cars), trucks (lorries), mopeds, light motor vehicles, motorcycles, buses (COM) or tractors.

The central release housing has the function of accommodating components of the central release, in particular the movable central release piston, and protecting them from external mechanical or chemical influences. Furthermore, the central release housing has the function of allowing simple assembly and fixing of the central release within the drive train. The central slave housing can be made in one piece or in several pieces. The central slave cylinder housing can preferably be formed from a plastic, a metallic material and/or a ceramic material.

The central release piston chamber formed in the central release housing serves to accommodate and guide the central release piston, which is linearly movably mounted in the central release housing.

In a hydraulic release system of a motor vehicle, the hydraulic fluid has the function of transferring energy in the form of pressure with as little loss as possible, for example within a clutch system of a vehicle.

In addition to this main task, the hydraulic fluid can also provide lubrication and corrosion protection for the moving parts and the metal surfaces of the hydraulic release system. In addition, it can in particular also dissipate contaminants (e.g. due to abrasion), water and air as well as heat loss.

The central slave cylinder has the function of converting a hydraulic pressurization into a linear displacement of the central slave cylinder, which causes the clutch system to be transferrable from an engaged operating state to a disengaged operating state. The central slave can have a ring-shaped central slave or several central slave (multi-piston release).

Furthermore, it can be advantageous for the metallic sensor body to be arranged in or on a carrier element, which results in greater structural flexibility with regard to the arrangement and coupling of the sensor body the other components, in particular with the fastening ring, results.

In a further development of the invention, it can also be preferred that the carrier element is formed from a material that is different from the material of the metallic sensor body, in particular the carrier element is formed from a plastic. This allows the construction to be further simplified. In particular, the metallic sensor body can be completely or partially surrounded by a plastic material from which the carrier element is formed. By embedding it in a preferably closed pocket within the carrier element, the sensor body can be protected from damaging mechanical and chemical influences, as a result of which the measuring accuracy can be ensured even over a long period of operation.

Furthermore, it can be advantageous that a fastening ring is coupled to the central release piston, so that an axial offset of the central release piston causes an axial offset of the fastening ring, the carrier element being fixable on the fastening ring. This results in a particularly flexible possibility of connecting the carrier element to the central slave cylinder. The fixation of the carrier element on the fastening ring is preferably carried out without play.

According to a further advantageous embodiment of the invention, it can be preferred that the inductive sensor unit can be coupled to the central slave housing. As a result, the sensor unit can be arranged and mounted on an existing concentric slave cylinder in particular in a simple manner.

According to a preferred embodiment of the invention, it can be advantageous for the metallic sensor body to be formed from aluminum and/or copper. These materials have proven to be particularly favorable as sensory targets for inductively determining the position of the central slave cylinder.

In a further preferred embodiment of the invention, it can be preferred that a fastening ring is coupled to the central release piston, so that an axial offset of the central release piston causes an axial offset of the fastening ring, the carrier element being fixable on the fastening ring. As a result, a mechanical coupling between the central slave cylinder and the carrier element can be implemented in a simple and flexible manner.

It may also be preferable for the fastening ring to be formed from a ferromagnetic material, as a result of which the play-free design can be provided particularly easily and inexpensively by means of a magnetic force.

According to another preferred embodiment of the invention, the carrier element is made of a plastic. As a result, it can be produced particularly cost-effectively and, for example, a sensor body and/or a magnetic element can also be incorporated into the carrier element in a manner that is favorable in terms of production technology.

It can also be preferred that the carrier element has a U-shaped fastening section which interacts with the fastening ring in such a way that the carrier element can be slipped onto the fastening ring from the radial direction, as a result of which a very easy-to-assemble embodiment of the invention can be provided.

In order to realize a particularly effective axially play-free embodiment of the invention, it may be preferable for the at least one magnetic element to be on and/or in the U-shaped fastening section, particularly preferably on and/or in one of the free legs of the U-shaped fastening section , Is arranged and/or the at least one magnetic element is arranged on and/or in the fastening ring.

In order to provide a captive and easy-to-assemble embodiment of the invention, it can also be preferred that the at least one magnetic element is encapsulated in and/or on the carrier element by a plastic and/or the at least one magnetic element is in and/or on the fastening ring of is overmoulded with plastic.

According to a highly preferred embodiment, it can be provided that the sensor unit is an inductive sensor unit, as a result of which particularly precise position measurements of the central slave cylinder piston can be carried out. In this context, it is also preferred that inductive conductor tracks of the inductive sensor unit extend in an axial direction parallel to the central slave cylinder and the metallic sensor body is arranged in the radial direction between the central slave cylinder housing and the induction conductor tracks.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea. The figures are only of a schematic nature and serve exclusively for understanding the invention. The same elements are provided with the same reference numbers. Also can the different Features of the various embodiments are freely combined within what is technically feasible.

• 1 eine schematische Querschnittsansicht einer ersten Ausführungsform eines erfindungsgemäßen Zentralausrückers,
• 2 eine schematische Querschnittsansicht einer zweiten Ausführungsform eines erfindungsgemäßen Zentralausrückers, und
• 3 ein Kraftfahrzeug mit einem erfindungsgemäßen Zentralausrücker.

Show it:

• 1 a schematic cross-sectional view of a first embodiment of a concentric slave cylinder according to the invention,
• 2 a schematic cross-sectional view of a second embodiment of a central slave cylinder according to the invention, and
• 3 a motor vehicle with a concentric slave cylinder according to the invention.

1 and the 2 each show a possible embodiment of a central slave cylinder 1 according to the invention for a hydraulic release system 2 of a clutch system 3 of a motor vehicle 4, as exemplified in FIG 3 is shown. The dash-dot line in the 1 and 2 indicates the axis of rotation of the clutch system 3 .

The central release mechanism 1 comprises a central release mechanism housing 5 with an annular central release mechanism piston chamber 6 in which a central release mechanism piston 8 is accommodated in an axially movable manner through a hydraulic fluid 7 that can be fed to the central release mechanism piston chamber 6 . An inductive sensor unit 9 , which includes an electronic sensor controller 10 and inductive conductor tracks 11 connected to the electronic sensor controller 10 , is arranged on the central slave cylinder housing 5 .

A metal sensor body 12 is coupled to the central release piston 8 in such a way that a linear offset of the central release piston 8 in the axial direction causes a backlash-free linear offset of the metal sensor body 12 . The induction conductor tracks 11 extend in an axial direction parallel to the central release piston 8. The metallic sensor body 12 is arranged in the radial direction between the central releaser housing 5 and the induction conductor tracks 11. The metallic sensor body 12 has a plate-like three-dimensional shape with a height in the radial direction of between 0.2-5 mm, preferably between 0.5-3 mm, so that a very compact radial design of the concentric slave cylinder 1 can be implemented.

The metallic sensor body 12 is arranged in or on a carrier element 13 . In the example shown, it is formed from aluminum and/or copper. The carrier element 13 is made of a material that is different from the material of the metallic sensor body 12 . In the exemplary embodiment shown, the carrier element 13 is formed from a plastic.

If the sensor body 12 is axially displaced within the sensor unit 9 , an electrical signal is generated by the sensor unit 9 that corresponds to the linear, axial displacement of the sensor body 12 and thus of the central slave cylinder 8 .

In principle, however, it would also be conceivable for the metallic sensor body 12 and the carrier element 13 to be formed from the same material. In particular, it would then also be possible for the metallic sensor body 12 and the carrier element 13 to be of monolithic design.

The sensor body 12 is arranged in or on a carrier element 13 coupled to the central release piston 8 , so that a linear displacement of the central release piston 8 causes a linear displacement of the sensor body 12 . In order to compensate for axial play at the interface between the carrier element 13 and the central release piston 8, which is caused by wear and tear as the operating time increases, the carrier element 13 has at least one magnetic element 15, which applies a magnetic force to the carrier element 13 at least in the direction of the linear offset of the central release piston 8 relative to the central release piston 8 fixed. This is in the embodiment of 1 shown. A supplementary or alternative embodiment to this is shown in FIG 2 , in which the central release piston 8 has at least one magnetic element 15, which fixes the carrier element 13 by magnetic force, at least in the direction of the linear offset of the central release piston 8 relative to the central release piston 8. It goes without saying that both the carrier element 13 and the fastening ring 14 can have magnetic elements 15 which attract one another.

in the in 1 shown embodiment, the fastening ring 14 is formed from a ferromagnetic material, so that a magnetic attraction between the magnetic element 15 in or on the carrier element 13 and the fastening ring 14 can be formed. The carrier element 13 is formed from a plastic. The magnetic element 15 is arranged on and/or in one of the free legs of the U-shaped fastening section 16 . The magnetic element 15 is encapsulated in and/or on the carrier element 13 by the plastic of the carrier element 13 .

In the in the 2 In the embodiment shown, in which the magnetic element 15 is arranged on or in the fastening ring 14, a ferromagnetic element 17 can be arranged opposite the magnetic element 15 in the axial direction in the carrier element 13 in order to ensure an axial, play-free fixing of the carrier element 13 on the Fastening ring 14 produced by magnetic force len. The carrier element 13 is then formed from a plastic, and the ferromagnetic element 17 is completely or partially encapsulated in plastic and is thus fixed in the carrier element 13 . In principle, it is also conceivable that the entire carrier element 13 is not formed from a plastic but from a ferromagnetic material. The magnetic element 15 can also be encapsulated in and/or on the fastening ring 14 by a plastic.

The directional information used in this application, axial, radial, tangential and/or circumferential, relates to an imaginary axis of rotation of the component concerned or described in each case.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

concentric slave cylinder

2

hydraulic release system

3

clutch system

4

motor vehicle

5

central slave housing

6

Central slave piston chamber

7

hydraulic fluid

8th

Concentric slave cylinder

9

sensor unit

10

electronic sensor control

11

induction traces

12

sensor body

13

carrier element

14

mounting ring

15

magnetic element

16

attachment section

17

ferromagnetic element

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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

• EP 1898111 B1 [0002]

Claims (9)

Central release mechanism (1), in particular for a hydraulic release system (2) of a clutch system (3) of a motor vehicle (4), comprising a central release mechanism housing (5) with an annular central release mechanism piston chamber (6) in the hydraulic fluid (7 ) a central release piston (8) is accommodated in an axially movable manner, with a sensor unit (9) being stationarily arranged on the central releaser housing (5), and a sensor body (12) thus being arranged in or on a carrier element (13) coupled to the central release piston (8). is that a linear displacement of the central release piston (8) causes a linear displacement of the sensor body (12), characterized in that the carrier element (13) has at least one magnetic element (15) which causes the carrier element (13) to have a magnetic force at least in the direction of the linear Offset of the central release piston (8) in relation to the central release piston (8) and/or the central release piston (8) has at least one magnetic element (15) which fixes the carrier element (13) by magnetic force at least in the direction of the linear offset of the central release piston (8) relative to the central release piston (8). Concentric slave cylinder (1), after claim 1 , characterized in that a fastening ring (14) is coupled to the central release piston (8), so that an axial displacement of the central release piston (8) causes an axial displacement of the fastening ring (14), the carrier element (13) being attached to the fastening ring (14 ) can be fixed. Concentric slave cylinder (1), after claim 2 , characterized in that the fastening ring (14) is formed from a ferromagnetic material. Central release device (1) according to one of the preceding claims, characterized in that the carrier element (13) is formed from a plastic. Concentric slave cylinder (1), according to one of claims 2 - 4 , characterized in that the carrier element (13) has a U-shaped fastening section (16) which cooperates with the fastening ring (14) in such a way that the carrier element (13) can be pushed onto the fastening ring (14) from the radial direction. Concentric slave cylinder (1), after claim 5 , characterized in that the at least one magnet element (15) is arranged on and/or in the U-shaped fastening section (16), particularly preferably on and/or in one of the free legs of the U-shaped fastening section (16) and/or or the at least one magnetic element (15) is arranged on and/or in the fastening ring (14). Concentric slave cylinder (1), according to one of Claims 5 - 6 , characterized in that the at least one magnetic element (15) in and/or on the carrier element (13) is encapsulated by a plastic and/or the at least one magnetic element (15) in and/or on the fastening ring (14) by a plastic is overmoulded. Central release device (1) according to one of the preceding claims, characterized in that the sensor unit (9) is an inductive sensor unit. Concentric slave cylinder (1), after claim 8 , characterized in that inductive conductor tracks (11) of the inductive sensor unit (9) extend in an axial direction parallel to the central release piston (8) and the metallic sensor body (12) is arranged in the radial direction between the central releaser housing (5) and the induction conductor tracks (11). .

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