CN110612401B

CN110612401B - Driven cylinder

Info

Publication number: CN110612401B
Application number: CN201880030227.7A
Authority: CN
Inventors: 加埃唐·布雷特; 斯蒂芬妮·罗凯; 菲利普·瓦格纳
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2017-05-10
Filing date: 2018-04-23
Publication date: 2021-04-02
Anticipated expiration: 2038-04-23
Also published as: DE102017110062B3; WO2018206045A1; CN110612401A

Abstract

The invention relates to a slave cylinder (20) having a housing (25) in which a piston (60) is guided so as to be movable back and forth between a rest position and a working position, wherein an interface (65) between the piston (60) and the housing (25) is radially outwardly surrounded by a dust protection device (1), wherein a control bearing (64) is seated on a bearing-side end of the piston (60). In order to provide a slave cylinder which operates stably and/or has a long service life, the slave cylinder (20) is sealed off from the surroundings at the end (10) of the dust protection device (1) facing away from the actuating bearing (64) in order to prevent air exchange with the surroundings at this point.

Description

Driven cylinder

Technical Field

The invention relates to a slave cylinder having a housing in which a piston is guided so as to be movable back and forth between a rest position and an operating position, wherein an interface between the piston and the housing is surrounded radially on the outside by a dust protection device, wherein a control bearing is seated on a bearing-side end of the piston.

Background

From international publication WO 2006/136132a1, a clutch slave cylinder device is known, which has a slave cylinder housing in which a piston is guided in a manner that can be moved back and forth between a rest position and an operating position, wherein the interface between the piston and the slave cylinder housing is surrounded radially on the outside by a cover device, which is formed from a relatively hard plastic material and has the shape of a sleeve which is fastened on the end side to the slave cylinder housing in a detachable manner, i.e. in a manner that can be repeatedly detached without damage.

Disclosure of Invention

The object of the invention is to provide a slave cylinder having a housing in which a piston is guided so as to be movable back and forth between a rest position and a working position, wherein the interface between the piston and the housing is surrounded radially on the outside by a dust protection device, wherein a control bearing is seated on the bearing-side end of the piston, wherein the slave cylinder is stable in operation and/or has a long service life.

A slave cylinder has a housing in which a piston is guided so as to be movable back and forth between a rest position and an operating position, wherein an interface between the piston and the housing is surrounded radially on the outside by a dust-protection device, wherein a control bearing is arranged on the bearing-side end of the piston, wherein the task is solved in that the slave cylinder is sealed off from the environment at the end of the dust-protection device facing away from the control bearing in order to prevent air exchange with the environment at this point. In this way, an undesired penetration of foreign particles is prevented in a simple manner at this point in the slave cylinder. The piston can be moved back and forth in the axial direction between its rest position and its operating position. The term "axial" relates to the longitudinal axis of the slave cylinder. "axial" means in the direction of or parallel to the longitudinal axis of the slave cylinder. By "radial" is meant transverse to the longitudinal axis of the slave cylinder. The dust protection device is preferably formed of an elastomeric plastic or rubber material and is equipped with a radially outwardly extending projection. These radially outwardly extending projections are preferably connected in one piece with a dust protection device, which is embodied for example as a bellows. A dust protection device with a radially outwardly extending projection can be manufactured inexpensively in large numbers, for example in an injection molding process. The slave cylinder is preferably embodied as a concentric clutch slave cylinder, which has a central through bore. At least one transmission shaft may extend through the central through hole, for example. The housing of the slave cylinder is formed, for example, from a plastic material.

A preferred embodiment of the slave cylinder is characterized in that an annular sealing element is provided at the end of the dust protection at a distance from the actuating bearing, which annular sealing element rests against the housing of the slave cylinder. In this way, foreign particles are reliably prevented from penetrating into the slave cylinder between the end of the dust protection device facing away from the actuating bearing and the housing in a simple manner. The annular sealing element is advantageously prestressed at least in part against the housing of the slave cylinder by means of a preload spring.

A further preferred embodiment of the slave cylinder is characterized in that the annular sealing element comprises a sealing collar which is formed on the end of the dust protection device facing away from the actuating bearing. The sealing collar is preferably connected integrally to the dust protection device. The sealing collar may protrude from the dust protection device in an axial direction prior to mounting. During installation, the sealing collar is preferably bent radially inward at substantially right angles from the dust protection device. The bent sealing collar is advantageously loaded by the end turns of the preload spring. This makes it possible for the dust protection device to be reliably held on the housing of the slave cylinder during operation of the slave cylinder without foreign particles reaching the slave cylinder at this point.

A further preferred embodiment of the slave cylinder is characterized in that, in the mounted state, the annular sealing element is clamped between the end turns of the preload spring and the housing of the slave cylinder. The preferably inwardly bent sealing collar of the annular sealing element is thereby advantageously held in a tight contact with the housing of the slave cylinder.

A further preferred embodiment of the slave cylinder is characterized in that an annular sealing element is provided on the end of the hook which is formed on the end of the dust protection device facing away from the actuating bearing. The hook is advantageously inserted into a housing receptacle of the housing of the slave cylinder in order to hold the dust protection device on the housing in the axial direction. The housing receptacle can be produced, for example, by injection molding using a suitable tool. In order to fasten the dust protection device stably to the housing, a housing receptacle is provided on the housing, preferably at least three projections for the hook element extending radially outward. The number of housing receiving portions on the housing does not necessarily correspond to the number of radially outwardly extending projections. For example, it is possible for the dust protection device to have, on one end, radially outwardly extending projections which are separated from one another over the entire circumference by slits. The number of the housing accommodating portions may be smaller than the number of the radially outwardly extending projections. In principle, however, it is also possible for the number of projections extending radially outward to be smaller than the number of housing receptacles. Of course, the number of the radially outwardly extending projections may also correspond to the number of the housing accommodating portions. If the housing receptacle is embodied, for example, circumferentially, the housing can also have only a single housing receptacle. Such a circumferential housing receptacle can be represented, for example, by a continuous rib. Such a continuous rib is preferably embodied as a ring-shaped body.

A further preferred embodiment of the slave cylinder is characterized in that a gap is provided in the circumferential direction between the hooks, which gap is closed by a diaphragm, which is connected in one piece with the annular sealing element. A sufficient movement possibility for the hooks can be presented by the gaps between the hooks. However, the gaps may be undesirably penetrated by air with foreign particles, if necessary. For this purpose, the slit or the recess is closed by a diaphragm. However, the membrane is advantageously thin and elastic, so that the hook can be opened during or after installation.

A further preferred embodiment of the slave cylinder is characterized in that a recess is provided on the bearing-side end of the piston, which recess enables an air exchange with the surroundings. Air exchange with the surroundings is required in order to ensure stable operation of the slave cylinder without damage on the bellows. However, the air exchange at the bearing-side end of the piston is considerably less critical with regard to the undesired penetration of foreign particles into the slave cylinder, in particular compared to the air exchange at the end of the dust protection device facing away from the actuating bearing.

A further preferred embodiment of the slave cylinder is characterized in that the recess on the bearing-side end of the piston is a recess (Einschuhung) which enables an air exchange between the central through-opening of the actuating bearing and an annular space which is bounded below the actuating bearing by a dust-protection device. In this way, the air exchange with the surroundings required for operating the slave cylinder, more precisely at locations that are not critical for the undesired penetration of foreign particles into the slave cylinder, can be achieved in a simple manner.

A further preferred embodiment of the slave cylinder is characterized in that the dust protection is embodied as a bellows. The bellows is advantageously formed from an elastomeric plastic or rubber material. The radially outwardly extending projections are preferably integrally connected with the corrugations of the bellows via the flange and the hook.

A further preferred embodiment of the slave cylinder is characterized in that a radially outwardly extending projection of the dust protection device is provided on the hook. The hooks are preferably distributed uniformly over the circumference at the end of the dust protection device. Thereby simplifying manufacture and installation of the dust protection device.

A further preferred embodiment of the slave cylinder is characterized in that the hook starts from a flange which rests on a rib which delimits the housing receptacle or receptacles. The rib edge may be interrupted in the circumferential direction, i.e. the rib edge does not necessarily have to be embodied circumferentially. The web is integrally connected to the annular body of the housing of the slave cylinder, for example, by a connecting tongue. The housing receptacle is then delimited in the circumferential direction by the connecting tongue.

A further preferred embodiment of the slave cylinder is characterized in that the housing receptacle has a retaining edge which acts in the axial direction for a radially outwardly extending projection of the dustproof device. The retaining edge is preferably arranged radially inwardly on the rib in the region of the housing receptacle. This enables the radially outwardly extending projections to be inserted in the housing receptacle in a barbed manner. The retaining edge, which acts in the axial direction, allows the dust protection device to be held stably on the housing of the slave cylinder by means of the radially outwardly extending projection.

A further preferred embodiment of the slave cylinder is characterized in that the radially outwardly extending projection is prestressed radially outwardly by means of a preload spring. The hook member having the radially outwardly extending projection can be of limited flexibility or elastically deformable for mounting purposes. The hook element with the radially outwardly extending projection can be embodied as a catch hook. In the form of a catch, the radially outwardly extending projection of the dust protection device advantageously snaps into the housing receptacle during installation. In the research and attempts carried out within the scope of the present invention, it has proven to be particularly advantageous for the preload spring, which is preferably embodied as a helical compression spring, to be used for the fixed retention of the dust protection on the housing of the slave cylinder. A preload spring, which is preferably embodied as a helical compression spring, is used in the slave cylinder, for example, to preload a bearing for the clutch, in particular a release bearing, in the axial direction away from the slave cylinder. The dust protection device is fastened to the housing by additionally using a preload spring so that the preload spring achieves a dual function. This provides, in particular, the advantage that no additional components are required for the stable fastening of the dust protection device to the housing.

A further preferred embodiment of the slave cylinder is characterized in that at least one end turn of the preload spring abuts from the radially inner side against a radially outwardly extending lug. The outer diameter of at least one end turn of the preload spring is advantageously somewhat larger than the inner diameter of the end of the dust guard having a radially outwardly extending projection. In this way, it is achieved in a simple manner that the radially outwardly extending projection is pressed radially outward against the housing receptacle by the preload spring after the installation of the dust protection device. The contact area for at least one end turn of the preload spring on the dust protection device is preferably designed as an inclined section. Thereby simplifying installation of the preload spring. Depending on the embodiment of the preload spring, it is also possible to apply more than one end turn of the preload spring or one end turn and the other end turn of the preload spring against the radially outwardly extending projection. The mounting force is applied to the radially outwardly extending projection on the one hand by means of the preload spring. Furthermore, it is advantageously possible to apply a retaining force to the projections of the dust protection device in the housing receptacle by means of the preload spring in order to hold the dust protection device particularly securely or stably on the housing.

A further preferred embodiment of the slave cylinder is characterized in that the end turns of the preload spring are arranged in an annular space which is bounded radially on the inside by the cylinder wall and radially on the outside by the end of the dust protection device having a radially outwardly extending projection which engages in the housing receptacle. The cylinder wall is arranged outside the outer cylinder of the slave cylinder, for example. The slave cylinder, which is embodied as a concentric slave cylinder, comprises an inner cylinder which is concentric or coaxial with the outer cylinder. The inner cylinder delimits the previously described central through-opening for the passage of the transmission shaft. An annular space for guiding the slave piston is formed between the inner cylinder and the outer cylinder. The concentric slave cylinder thus comprises two coaxially or concentrically arranged annular spaces. The radially outer annular space is an axial stop for preloading the end turns of the spring. The housing receiver extends substantially radially outward from the annular space.

The invention furthermore relates to a dust-protection device, a piston and/or a housing for a slave cylinder as described above. The mentioned parts are separately marketable.

Drawings

Additional advantages, features and details of the invention are derived from the following description, in which different embodiments are described in detail with reference to the drawings. Wherein:

fig. 1 shows a slave cylinder in longitudinal section, with a housing in which a piston is guided in a manner movable to and fro, and with a dust-protection device which rests with one end on an actuating bearing;

fig. 2 shows a perspective view of the end of the dust protection device facing away from the actuating bearing;

fig. 3 shows a longitudinal section through a dust protection device;

fig. 4 shows an enlarged view of detail IV of fig. 2;

fig. 5 shows an enlarged view of detail V of fig. 1;

FIG. 6 shows a perspective view of the piston; and is

Fig. 7 shows an enlarged view of detail VII of fig. 1.

Detailed Description

Fig. 1 shows a slave cylinder 20 with a housing 25 in longitudinal section. The housing 25 of the slave cylinder 20 includes an inner cylinder 21 and an outer cylinder 22. The inner cylinder 21 delimits a central passage opening 28 radially on the inside, which is used, for example, for the passage of a transmission shaft.

An annular space 24 is formed between the inner cylinder 21 and the outer cylinder 22. The outer cylinder 22 has a cylinder wall 23 radially outside. The housing 25 comprises an annular body 26 via which the inner cylinder 21 is integrally connected with the outer cylinder 22.

The rib 30 provided radially on the outside on the housing 25 delimits an annular space 45 arranged coaxially with the annular space 24. The annular space 45 is bounded radially inwardly by the cylinder wall 23 of the outer cylinder 22. In the axial direction, the annular space 45 is delimited in fig. 1 below by the annular body 26 of the housing 25.

Radially outside, the annular space 45 is delimited by the rib 30. The rib 30 is integrally connected to the annular body 26 of the housing 25 via the connecting tongue 27. The rib with the connecting tongue 27 serves to represent a housing receptacle on the housing 25, which is not shown in detail in fig. 1. The housing receptacles are each intended to receive a

projection

15, 17, which are formed at the end of the hooks 11 to 14.

Fig. 2 shows that a plurality of hooks 11 to 14 are formed on the end of the dust protection device 1 facing away from the actuating bearing 64, on which hooks

projections

15, 17 each project radially outward. The housing receptacles, not shown in detail, of the housing 25 are each intended to receive one of the

projections

15, 17 of the hooks 11 to 14.

The dust protection 1 is embodied as a bellows 3. The bellows 3 is formed of an elastic body type rubber material and is equipped with a corrugated portion 5. The upper end 8 of the bellows 3 in fig. 1 is assigned to a control bearing 64, which is also referred to as a release bearing. Hooks (11 to 14 in fig. 2) are formed on the lower end 10 of the dust protection device 1 in fig. 1.

Radially outwardly extending

projections

15, 17 are formed on the free ends of the hooks 11 to 14. A total of eighteen hooks are formed on the end 10 of the bellows 3, each having a projection extending radially outward. The hooks 11 to 14 are arranged evenly distributed in the circumferential direction. A gap 18 is provided between the two

hook elements

11, 12.

The slave cylinder 20 includes a preload spring 40, which is embodied as a helical compression spring. The end turn 44 at the lower end of the preload spring 40 is associated with the end 10 of the bellows 3 facing away from the actuating bearing 64. The bellows 3 has a flange 50 on its end 10. The flange 50 extends radially outwardly and rests on the bead 30 of the housing 25. The flange 50 is integrally connected to the corrugated portion 5 of the corrugated tube 3.

The hook 11 extends obliquely downward from the flange 50. The projection 15 is integrally connected with the flange 50 via the hook 11. The end turns 44 of preload spring 40 contact the hook 11 of bellows 3.

In the installed state, the end turns 44 of preload spring 40 rest against the annular body 26 of housing 25. The

projections

15, 17 on the ends of the hooks 11 to 14 are pressed radially outwards by preloading the end turns 44 of the spring 40.

Hooks 11 to 14 on end 10 of bellows 3 are moved by end turns 44 outward toward rib 30 during the installation of preload spring 40, so that radially outward-extending

projections

15, 17 on the ends of hooks 11 to 14 are pressed into the housing receptacle. The projection 15 is hooked in a barbed manner on the retaining edge of the bead 30.

Due to a suitable radially outward pretensioning of the end turns 44 of the preload spring 40, the hooks 11 to 14 are held stably in the housing receptacles by the projections 15. The bellows 3 is held firmly in the axial direction on the housing 25 by means of a barb-type hook.

The slave cylinder 20 furthermore comprises a piston 60. The piston 60 is guided in the annular space 24 by means of a groove ring seal 62. Annular space 24 is the hydraulic pressure chamber of slave cylinder 20. The piston 60 can be moved downwards from its position shown in fig. 1.

The bellows 3 is arranged outside the interface 65 between the piston 60 and the housing 25. In this way, dirt, for example in the form of foreign particles, is prevented in a simple manner from reaching the interface 65 in an undesired manner. The bellows 3 is therefore also referred to as a dust protection device 1.

The bellows 3 rests with its upper end 8 in fig. 1 radially on the outside on an actuating bearing 64. The actuating bearing 64 comprises a plurality of parts, such as rolling bodies in the form of balls. Radially inwardly, the steering bearing 64 is located on the upper end of the piston 60 in fig. 1. The annular space 66 is bounded radially on the inside by the piston 60 and radially on the outside by the bellows 3. The annular space 66 is delimited upwards in fig. 1 by the actuating bearing 64.

Fig. 2 and 3 show that an annular sealing element 70 is formed at end 10 of bellows 3. The annular sealing element 70 comprises a sealing collar 71 which is integrally connected to the

projections

15, 17 on the hooks 11 to 14.

The sealing collar 71 is connected integrally to a membrane 73, which closes the gap 18 between two

adjacent hooks

12, 13. The membrane 73 has substantially the same thickness as the sealing neck rim 71. In fig. 3, it is indicated by circle II that bellows 3 has a continuously closed surface axially inside below flange 50.

In the enlarged view of fig. 4, it is seen that the membrane 73 completely fills the gap 18 between the

hooks

12 and 13. As the membrane 73 has a smaller thickness compared to the thickness of the

hooks

12, 13, a recess 72 is obtained between the

hooks

12, 13. In fig. 4, the membrane 73 prevents an undesired penetration of air from the surroundings into the annular space (45 in fig. 1) as indicated by the arrow 74.

As seen in fig. 5, the sealing collar 71 is clamped between the end turns 44 of the preload spring and the annular body 26 of the housing in the mounted state of the slave cylinder. In fig. 5, the

arrows

75 and 76 indicate that the air exchange with the surroundings is reliably prevented at the lower end 10 of the bellows 3 by the sealing collar 71 in combination with the membrane 73 shown in fig. 4.

However, in order to ensure a perfect operation of slave cylinder 20, a sufficient air exchange between the radially inner annular space of bellows 3 and the surroundings is required. According to the basic idea of the invention, the air exchange is transferred from the lower end 10 of the bellows 3 to the upper end of the piston 60.

The upper end of the piston 60 is generally not critical with regard to the undesired penetration of dirt, in particular foreign particles, in the installed state of the slave cylinder 20. Furthermore, the centrifugal force of the air flow at the upper end of the piston 60 contributes to a favorable blow-off of dirt, in particular foreign particles.

In fig. 6, it is seen that the piston 60 has a recess 77 on its end facing the actuating bearing (64 in fig. 1). The piston 60 comprises a total of eight recesses 77, which are distributed uniformly over the circumference of the piston 60 at the upper end of the piston. The recess 77 exhibits a gap 78, which, as is illustrated in fig. 7 by the double arrow 79, enables the desired air exchange between the annular space 66 and the surroundings. The entry or exit of air takes place in the region of the central through-opening 80 in the actuating bearing 64.

List of reference numerals

1 dust-proof device

3 corrugated pipe

5 fold part

8 end part

10 end of

11 hook-shaped part

12 hook shaped piece

13 hook-shaped piece

14 hook shaped piece

15 bulge

17 projection

18 gap

20 slave cylinder

21 inner cylinder

22 outer cylinder

23 cylinder wall

24 annular space

25 casing

26 annular body

27 connecting tongue

28 center through hole

30 rib edge

40 preloaded spring

44 end turns

45 annular space

50 flange

60 piston

62 groove ring seal

64 operating bearing

65 interface

66 annular space

70 ring-shaped sealing element

71 sealing neck edge

72 recess

73 diaphragm

74 arrow head

75 arrow head

76 arrow head

77 concave part

78 gap

79 double arrow

80 center via

Claims

1. A slave cylinder (20) having a housing (25) in which a piston (60) is guided so as to be movable back and forth between a rest position and a working position, wherein an interface (65) between the piston (60) and the housing (25) is radially outwardly surrounded by a dust protection device (1), wherein a handling bearing (64) is seated on a bearing-side end of the piston (60), characterized in that the slave cylinder (20) is sealed off from the surroundings at an end (10) of the dust protection device (1) facing away from the handling bearing (64) in order to prevent air exchange with the surroundings at this location;

an annular sealing element (70) is arranged on the end (10) of the dust protection device (1) facing away from the actuating bearing (64), said sealing element resting against a housing (25) of the slave cylinder (20);

the annular sealing element (70) is arranged on the end of a hook which is formed on the end (10) of the dust protection device (1) facing away from the actuating bearing (64);

a gap (18) is provided in the circumferential direction between the hooks, said gap being closed by a membrane (73) which is connected in one piece to the annular sealing element (70).

2. The slave cylinder according to claim 1, characterized in that the annular sealing element (70) comprises a sealing collar (71) which is configured on the end (10) of the dust protection device (1) facing away from the actuating bearing (64).

3. Slave cylinder according to claim 2, characterized in that the annular sealing element (70) is clamped between the end turns (44) of the preload spring (40) and the housing (25) of the slave cylinder (20) in the mounted state.

4. Slave cylinder according to claim 1, characterized in that a recess (77) is provided on the bearing-side end of the piston (60), which recess enables an air exchange with the surroundings.

5. A slave cylinder according to claim 4, characterized in that the recess (77) on the bearing-side end of the piston is a gap (78) enabling air exchange between a central through hole (80) of the steering bearing (64) and an annular space (66) which is delimited by the dust protection (1) below the steering bearing (64).

6. A slave cylinder according to claim 1, characterized in that the dust protection device (1) is embodied as a bellows (3).

7. A slave cylinder according to claim 1, characterized in that the hooks are evenly distributed in the circumferential direction at the end of the dust protection device (1).

8. A slave cylinder according to claim 1, characterized in that a radially outwardly extending projection (15, 17) is provided at the hook.

9. The slave cylinder according to one of claims 1 to 8, characterized in that the housing receptacle of the housing (25) has a retaining edge which acts in the axial direction against a radially outwardly extending projection (15, 17) of the dust protection device (1).

10. A dust prevention apparatus for a slave cylinder according to any one of claims 1 to 9.

11. A piston for a slave cylinder according to any of claims 1 to 9.

12. A housing for a slave cylinder according to any of claims 1 to 9.