WO2018215014A1

WO2018215014A1 - Clutch slave cylinder with integrated distance measurement function

Info

Publication number: WO2018215014A1
Application number: PCT/DE2018/100386
Authority: WO
Inventors: Philippe Wagner; Michael Hofmann; Christian Henning
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2017-05-22
Filing date: 2018-04-23
Publication date: 2018-11-29
Also published as: DE102017111083B3

Abstract

The invention relates to a clutch slave cylinder (1) for moving a release bearing (11), comprising a cylinder housing (2), a piston (3), a magnet (6), and a magnetic field-sensitive sensor (63) for detecting the position of the piston (3) relative to the cylinder housing (2). The magnet (6) is secured to a magnet support (4), and the magnet support (4) is fixed in the axial direction of the piston (3) and can be moved in the radial direction of the piston (3) relative to the piston (3).

Description

Clutch slave cylinder with integrated displacement measurement

The invention relates to a clutch slave cylinder with integrated displacement measurement. Such a clutch slave cylinder includes a cylinder housing, a piston, a magnet, and a magnetic field sensitive sensor for detecting a position of the piston with respect to the cylinder housing, the magnet being fixed to a magnet carrier. The clutch slave cylinder serves to move a release bearing. Different magnetic fields of the magnet can be received by the sensor in different positions of the piston relative to the cylinder housing.

From the prior art, a variety of solutions for the arrangement of a magnetic recording on the clutch slave cylinder is known.

According to a solution according to the prior art by the coupling specialist LuK GmbH & Co. KG, Bühl, it is known to arrange a He- at a clutch slave cylinder, wherein on the lever, a magnetic receptacle is arranged, the magnet in a circular path around the sensor leads.

A disadvantage of the prior art is that positional errors can occur due to wobbling movements that can be induced by the release bearing.

This object is achieved by the features of the independent patent claim. Further advantageous developments are the subject of the dependent claims.

The invention relates to a clutch slave cylinder whose magnetic carrier is fixed relative to the piston in the axial direction of the piston and displaceable in the radial direction of the piston. This makes it possible to prevent relative movements between the sensor and the magnet from being transmitted to the magnetic field detection site. Since the magnetic-field-sensitive sensors used usually have not only a sensitivity to a change in the magnetic field with a displacement of the piston in its axial direction, but also a so-called cross-sensitivity to radial movements of the piston. These latter movements cause the magnet is transverse to the actual measurement direction of the sensor moves to this to or from this. This leads to measurement errors, since the sensors usually can not distinguish this from the desired measuring effect of detecting the movements of the piston in its axial direction. It is therefore advantageous to avoid a transverse movement between magnet and sensor at the detection point. Preferably, the clutch slave cylinder is configured such that play is present between the piston and an associated release bearing at least in the retracted state of the clutch slave cylinder, in particular in the radial direction of the piston. For example, a point at which the inner ring of the release bearing with its inner circumference can be accommodated on the clutch slave cylinder, have a smaller outer diameter than the inner diameter of the inner ring. By such a game a possible wobbling movement of the release bearing is decoupled from the piston. This also results in fewer measurement errors in the position detection of the piston.

The clutch slave cylinder preferably has a guide device, which is movable in the axial direction of the piston and guides in the radial direction of the piston, for guiding a relative movement between the magnet and the sensor. By means of such a guide device, the Querab- movement described above can be avoided. The guide means may comprise axially displaceable and radially-guiding complementary shapes of outer surfaces on the magnet holder and the cylinder housing.

Preferably, the clutch slave cylinder has an anti-rotation between the magnetic carrier and the cylinder housing.

Basically, the piston is rotatable in the cylinder housing. However, since a rotation of the piston in the cylinder housing of the sensor and the magnet can get out of alignment with the axial direction of movement of the piston, which in turn can lead to measurement errors or dysfunction, it is advantageous to provide a rotation.

In particular, the magnet is submersible with a movement of the piston in the axial direction in a submerged opening, which is connected to the cylinder housing. This movement takes place along a direction of immersion. The immersion direction preferably corresponds to the axial direction of the piston. One or more walls of the immersion opening may be used as guide means for guiding the magnet with respect to serve the sensor. Preferably, the sensor or a sensor housing is connected to a wall of the immersion opening. The immersion opening is preferably closed transversely to the immersion direction on at least two sides, preferably on all sides. A side wall may be broken as a passage for a magnetic carrier. With a non-circular configuration of the immersion opening an anti-rotation can be realized, preferably at the same time a guide is realized in the radial direction of the piston. Preferably, the play between the magnet or a magnet holder, which is provided for immersion in the immersion opening, so small that the measurement accuracy is not significantly affected by the game. Preferably, a rotation of the clutch slave cylinder is designed as a positive, displaceable in the axial direction of the piston connection between the magnet carrier and the cylinder housing. This can be realized for example by a groove or a slot in the magnet carrier and complementary to a projection on the cylinder housing. Alternatively or additionally, a projection on the magnet holder and a slot or a groove may be arranged in the cylinder housing.

In particular, the magnetic carrier is designed as a magnetic carrier ring. A ring has good stability compared to elongate components and is more compact. In addition, one can be arranged around the cylinder housing, which saves space. A magnetic carrier ring can be performed at the same time with function as a dirt protection ring. Alternatively, the dirt protection can be achieved via other structural solutions such as, for example, a bellows.

The magnet carrier can be made in one piece and in particular as an injection molded part. The magnet can be encapsulated by the magnetic carrier ring. A magnet carrier ring may also form part of a guide device. For example, letters may be a guide formed between the outer peripheral portion of the magnetic carrier ring and an inner peripheral portion of the cylinder housing.

Preferably, the magnetic carrier is pressed by a release spring to a connected to the piston component of the clutch slave cylinder, in particular to a bearing inner ring of the release bearing. With this solution, the release spring can be used twice, which reduces the additional cost of the measuring device. The magnetic carrier ring may for example have a collar which protrudes in the axial direction on an end face. Such a collar can serve as a stop for possible radial displacements of the magnetic carrier ring, in particular with respect to the inner ring of the release bearing. Preferably, the sensor or sensor housing of the sensor is located at or near the outer periphery of a portion of the cylinder housing that extends around the piston.

The arrangement of the sensor near the outer periphery of a portion of the cylinder housing that extends around the piston in particular means that between the outer circumference and the sensor can be arranged as follows:

- A sensor housing and / or

a guide device which can serve to achieve a desired relative movement between magnet and sensor, and / or

- a compact sensor holder. Compact means that the largest dimension of the sensor holder is considerably smaller than the largest dimension of the clutch slave cylinder.

The distance between the sensor and the outer periphery of the cylinder housing to which one is attached may e.g. be smaller than half the outer diameter of the largest at least approximately round portion of the cylinder housing. The above-described configuration of the clutch slave cylinder causes the sensor as a detection point of the magnetic field of the magnet has a shorter distance to the piston than in the prior art. Tumble motions of the piston, which it may perform, for example, by the action of a release bearing, are less significant at the point of detection because they are less magnified by the lower leverage of the distance to the piston than in the prior art.

There may be more than one magnet, in particular exactly two magnets, attached to the magnetic carrier. With several magnets, a better accuracy and / or a longer measuring path can be achieved. In other words, the invention can be described as follows. In order to realize a compact and inexpensive sensor arrangement for a clutch slave cylinder, a clutch slave cylinder is provided with attached magnetic carrier ring on which the magnet can be mounted. In order not to transfer the tumbling movements in the bearing on the magnet, a radial compensation between the magnetic carrier ring and the inner ring of the release bearing is provided. The axially play-free guidance of the magnetic carrier ring is ensured by the release spring, which presses the magnetic carrier ring axially against the bearing. An anti-rotation of the magnetic carrier ring relative to the housing is effected by axial grooves or springs. It is also possible to connect the magnets by means of adhesive bonding or as encapsulated insert with the ring body. It is also possible to attach a magnet holder by means of one or more snap connections on the magnetic carrier ring.

To allow the bearing radial movements, preferably a gap between see piston and release bearing is provided. In order not to transmit the tumbling movements of the release bearing on the magnet, a radial compensation between the ring body and the inner ring of the release bearing can be provided. The annular body is preferably pressed by the axial force of the release spring to the release bearing. This ensures an axially play-free guidance. In this variant, the magnetic attachment preferably takes place by means of snap-fit connections on the annular body.

The annular body can be guided axially and radially through the outer ring provided on the housing. The rotation of the ring body can be done by axial grooves with the complementarily shaped opposite side of the cylinder housing.

Another embodiment differs from the embodiment described above, especially in the magnetic guide and magnet holder. Trained as a dirt protection magnetic carrier ring can be pressed as well as in the embodiment described above, the magnetic carrier ring by the release spring to the camp. However, the guide and anti-rotation protection preferably do not take place over the entire diameter, but rather via a special geometry in which the magnets can be moved axially with small tolerances for tilting, rotation and radial play. This is to ensure that the magnets stay as consistent as possible. the distance to the sensitive element of the sensor on this axially past.

The invention will be explained in more detail with reference to an embodiment in conjunction with accompanying drawings. Here are shown schematically:

Fig. 1 is a sectional view of a clutch slave cylinder after

State of the art;

2 shows a half-sectional view of a clutch slave cylinder according to the invention in a first embodiment, wherein the illustrated clutch slave cylinder is shown in the extended state,

3 is a perspective view of the clutch slave cylinder of the first embodiment in the extended state,

4 shows a half-sectional view of a clutch slave cylinder according to the invention in a second embodiment, wherein the illustrated clutch slave cylinder is shown in the retracted state,

Fig. 5 is a plan view of a sensor housing and a magnet holder of the second embodiment; Fig. 6 is a half-sectional view of a clutch slave cylinder in the second embodiment, wherein the illustrated clutch slave cylinder is shown in the extended state, and

7 is a perspective view of the clutch slave cylinder in the second embodiment, wherein the illustrated clutch slave cylinder is shown in the extended state.

Figure 1 shows a section through a clutch slave cylinder 1, which comprises a cylinder housing 2, a piston 3, a dirt protection ring 5 and a release bearing 1 1 with an inner ring 10, rolling elements 9 and an outer ring 8. The piston 3 is annular and shown in the extended state. A part of the piston 3 is arranged in an annular cylinder chamber 21. The piston 3 is opposite the cylinder chamber 21 sealed with a seal 31. On the cylinder housing 2, a support arm 22 is arranged, on which a sensor carrier 23 is arranged with a sensor not explicitly shown. The sensor is in operative connection with a magnet 6, which is arranged in a magnetic holding device 43. The magnetic holding device 43 is arranged on a magnet carrier 4, which is mechanically connected to the dirt protection ring 5. When the piston 3 moves in the cylinder chamber 21, moves with the piston of the inner ring 10, the dirt protection ring, the magnetic carrier 42 and the magnet holder 43 with the magnet 6. The magnet 6 sweeps along a surface facing him of the sensor carrier and generated in the Sensor according to its position a measuring signal. A disadvantage of this arrangement is that the magnetic carrier 4 and the magnet holder 43 cause the magnet 6 is far away from the guide between the piston 3 on the cylinder chamber 21 and thus translates relative movements between the piston 3 and the cylinder housing 2 with a large lever appear as a relative movement between the magnet 6 and the sensor carrier 23 and cause significant measurement errors there.

Fig. 2 shows a half-sectional view of a clutch slave cylinder 1 according to the invention in a first embodiment, wherein the illustrated Kupplungsneh- cylinder 1 is shown in the extended state. The piston 3 pushes the inner ring 10 of a release bearing 1 1 away from a cylinder chamber 21. Between the inner ring 10 and the piston 3 game is provided, so that their relative position may change. A release spring 7 is supported on the cylinder housing 2 and presses a magnetic holder 4 designed as a magnetic carrier ring 42 axially against the inner ring 10. The magnet holder 42 and the inner ring 10 have radial play with each other. The magnetic carrier ring 42 is radially movable and axially fixed in this way. The magnetic carrier ring 42 has a collar 41, which is arranged in the interior of the inner ring 10. The collar 41 may serve to limit the radial movement of the magnetic carrier ring 42. The magnetic carrier ring 42 has a magnetic receptacle 43, in which a magnet 6 is arranged. The magnet carrier ring 42 can retract together with the piston 3, with the magnet 6 approaching a sensor 63. By measuring changes in the magnetic field of the magnet 6 measured by the sensor 63, the position of the piston 3 can be determined. The sensor 63 is arranged in a sensor housing 64. The sensor housing 64 is mounted on a sensor bracket 23 is arranged. The sensor holder 23 is connected to the outer circumference 25 of the cylinder housing 2 with the cylinder housing 2. The sensor holder 23 has an immersion opening into which the magnet holder 43 with the magnet 6 can dip. The immersion opening is open in the direction of the cylinder housing 2. The magnetic carrier ring 42 can partially or completely close the immersion opening in the direction of the cylinder housing 2, depending on the position of the piston 3. The magnetic carrier ring 42 is disposed outside of the release spring 7 and surrounds it.

Fig. 3 shows a perspective view of the clutch slave cylinder of the first embodiment in the extended state. Identical features are designated by the same reference numerals and will not be described separately again. Reference is made to the comments on Figure 2.

FIG. 3 shows a slot 67 in the magnet carrier ring 4. This cooperates with a guide web 24 by the guide bar 24 projects into the slot 67. In this way, an anti-rotation between the Magnetträger- ring 42 and the cylinder housing 2 is realized. The slot 67 extends in the axial direction of the piston 3, so that a movement of the magnetic carrier ring 42 together with the piston 3 is possible.

4 shows a half-sectional view of a clutch slave cylinder 1 according to the invention in a second embodiment, wherein the illustrated clutch slave cylinder 1 is shown in the retracted state. The clutch slave cylinder 1 according to the second embodiment agrees in many details with the clutch slave cylinder according to the first embodiment. Identical features are designated by the same reference numerals and will not be explained separately again.

In contrast to the first embodiment, the clutch slave cylinder according to the second embodiment in its magnetic receptacle 43 not only one, but two magnets 61 and 62 on. The magnets 61 and 62 are spaced from each other in the axial direction of the piston 3. In the fully retracted state of the piston 3, the sensor 63 is arranged in the extension direction outside the distance between the magnets 61. When the piston 3 is moved out of the cylinder chamber 21, the magnet 61 first moves past the sensor 63, and in the course of the further extension of the piston 3, the magnet 62 also runs on the sensor 63 past. This results along the path of the piston 3 a characteristic course of the measurement result of the sensor 63, which correlates with the position of the piston 3.

The magnetic carrier ring 42 has a holding web 44 which projects radially outward from the annular part of the magnetic carrier ring 42. At the outer end of the holding web 44, the magnet holder 43 is arranged. The magnet holder 43 is guided in a sensor carrier 23, which has an immersion opening. The immersion opening is open in the direction of the cylinder housing 2, so that the retaining web 44 can dive through the open area. The immersion opening of the sensor carrier 23 is closely tolerated to the outer surfaces of the magnetic receptacle 23, so that the sensor carrier 23 acts as a guide for the magnetic carrier ring 4 and the magnetic receptacle 43. The sensor 63 is arranged in a sensor housing 64. The sensor housing 64 is arranged outside on the side facing away from the cylinder housing 2 of the sensor carrier 23.

Notwithstanding the first embodiment, an annular part of the magnet carrier ring 42 extends inside the disengagement spring 7. This makes it possible to make the clutch slave cylinder 1 more compact.

Fig. 5 shows a plan view of a sensor housing and a magnet holder of the second embodiment. Here, in the retraction direction of the piston 3, it can be seen how the magnetic receptacle 43 dips into the interior of the sensor carrier 23, which acts as a dipping opening. The magnetic receptacle 43 is connected via the holding web 44 with the magnetic carrier ring 42, which is not shown in Figure 5.

Fig. 6 shows a half-sectional view of a clutch slave cylinder 1 in the second embodiment, wherein the illustrated clutch slave cylinder 1 is shown in the extended state. FIG. 6 largely corresponds to FIG. 4. The same features are denoted by the same reference symbols and will not be described separately again.

In FIG. 6 it can be seen that both magnets 61 and 62 are in the extension direction when viewed from the sensor 63.

Fig. 7 shows a perspective view of the clutch slave cylinder 1 in the second embodiment, wherein the illustrated clutch slave cylinder 1 as shown in Figure 6 in the extended state. The magnetic carrier ring 42 extends inside the release spring 7. LIST OF REFERENCE NUMBERS

Clutch slave cylinder

Housing of the clutch slave cylinder

cylinder chamber

Bottom of the cylinder chamber

Beam

sensor support

guide web

Outer circumference of the cylinder housing

piston

poetry

magnet carrier

collar

Magnetic support ring

magnetic recording

holding web

guide means

Dirt guard ring

magnet

First magnet in the magnet holder

Second magnet of the magnetic recording

sensor

sensor housing

release spring

Outer ring of the release bearing

Rolling elements of the release bearing

Inner ring of the release bearing

release bearing

Claims

claims

Clutch slave cylinder (1) for moving a release bearing (1 1), comprising a cylinder housing (2), a piston (3), a magnet (6) and a magnetic field sensitive sensor (63) for detecting a position of the piston (3) with respect to the cylinder housing (2), wherein the magnet (6) is attached to a magnetic carrier (4),

characterized in that

the magnet carrier (4) is fixed relative to the piston (3) in the axial direction of the piston (3) and is displaceable in the radial direction of the piston (3).

Clutch slave cylinder (1) according to claim 1, characterized in that the clutch slave cylinder (1) designed such that between the piston (3) and provided for the clutch slave cylinder release bearing (1 1) at least in the retracted state of the clutch slave cylinder (1) a larger game as required for the assembly is present, in particular in the radial direction of the piston (3).

Clutch slave cylinder (1) according to one of the preceding claims, characterized in that the clutch slave cylinder (1) in the axial direction of the piston (3) movable and in the radial direction of the piston (3) leading guide means (45) for guiding a relative movement between the magnet (6) and the sensor (63).

Clutch slave cylinder (1) according to one of the preceding claims, characterized in that the clutch slave cylinder (1) has a rotation between the magnetic carrier (4) and the cylinder housing (2).

Clutch slave cylinder (1) according to claim 4, characterized in that the clutch slave cylinder (1) comprises a rotation as a positive, in the axial direction of the piston (3) displaceable connection between the magnet carrier (4) and the cylinder housing (2).

6. clutch slave cylinder (1) according to any one of the preceding claims, characterized in that a magnet (6) with a movement of the piston (3) in the axial direction in an immersion opening, which is connected to the cylinder housing (2), immersed along a dipping direction is, wherein the immersion opening is preferably closed transversely to the immersion direction on at least two sides, in particular opposite sides.

7. clutch slave cylinder (1) according to one of the preceding claims,

characterized in that the magnet carrier (4) can be pressed by a disengagement spring (7) to a component of the clutch slave cylinder (1) connected to the piston (3), in particular to a bearing inner race (10) of the release bearing (11).

8. clutch slave cylinder (1) according to one of the preceding claims,

characterized in that the magnetic carrier (4) is formed as a magnetic carrier ring (42).

9. clutch slave cylinder (1) according to claim 8, characterized in that the magnetic carrier ring (42) with a portion of the cylinder housing (2) a guide means (45) for guiding the magnetic carrier ring 42 on the cylinder housing (2) is formed, wherein an annular inner peripheral portion of Cylinder housing (2) and an annular outer peripheral portion of the magnetic carrier ring (42) as guide means (45) cooperate.

10. clutch slave cylinder (1) according to one of the preceding claims,

characterized in that the sensor (63) or sensor housing (64) of the sensor (63) is located at or near the outer periphery of a portion of the cylinder housing (2) extending around the piston (3).