WO2018206045A1

WO2018206045A1 - Slave cylinder

Info

Publication number: WO2018206045A1
Application number: PCT/DE2018/100383
Authority: WO
Inventors: Gaetan BRETHES; Stephane Rocquet; Philippe Wagner
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2017-05-10
Filing date: 2018-04-23
Publication date: 2018-11-15
Also published as: DE102017110062B3; CN110612401B; CN110612401A

Abstract

The invention relates to a slave cylinder (20) comprising a housing (25), in which a piston (60) is displaceably guided back and forth between a rest position and a working position, wherein an interface (65) between the piston (60) and the housing (25) is surrounded radially outside by a dirt protection device (1), wherein a actuating bearing (64) is attached to a bearing-side end of the piston (60). In order to devise a slave cylinder which functions stably and/or has a long service life, the slave cylinder (20) is sealed off with respect to the environment at an end (10) of the dirt protection device (1) facing away from the actuating bearing (64), in order to prevent an exchange of air with the environment at this point.

Description

slave cylinder

The invention relates to a slave cylinder with a housing in which a piston between a rest position and a working position is guided back and forth movable, wherein an interface between the piston and the housing is surrounded radially outwardly by a dirt protection device, wherein at a bearing end of the piston an actuating bearing is mounted.

From the international publication WO 2006/136132 A1 a clutch slave cylinder device with a slave cylinder housing is known, in which a piston between a rest position and a working position is moved back and forth, with an interface between the piston and the slave cylinder housing radially outward from a covering device is surrounded, which is formed of a relatively rigid plastic material and has the shape of a sleeve which releasably on a front side, that is repeatedly non-destructively separable, is attached to the slave cylinder housing. The object of the invention is a slave cylinder with a housing in which a piston between a rest position and a working position is guided back and forth movable, wherein an interface between the piston and the housing is radially outwardly surrounded by a dirt protection device, wherein on a bearing side End of the piston is provided an actuating bearing, which works stably and / or has a long life.

The object is in a slave cylinder with a housing in which a piston between a rest position and a working position is guided back and forth movable, wherein an interface between the piston and the housing is surrounded radially outwardly by a dirt protection device, wherein at a bearing end of the Piston an actuating bearing is mounted, achieved in that the slave cylinder at a side facing away from the actuating bearing end of Schmutzschutzvorrich- sealed against the environment to prevent an exchange of air with the environment at this point. As a result, undesired penetration of foreign particles at this point in the slave cylinder is prevented in a simple manner. The piston is movable in an axial direction between its rest position and its working position back and forth. The term axial refers to a longitudinal axis of the slave cylinder. Axial means in the direction or parallel to the longitudinal axis of the slave cylinder. Radial means transverse to the longitudinal axis of the slave cylinder. The dirt protection device is preferably formed from an elastomeric plastic or rubber material and equipped with radially outwardly extending projections. The radially outwardly extending projections are preferably integrally connected to the dirt protection device, which is designed for example as a bellows. The dirt protection device with the radially outwardly extending projections, for example by injection molding, can be produced inexpensively in large quantities. The slave cylinder is preferably designed as a concentric clutch slave cylinder with a central through hole. For example, at least one transmission shaft may extend through the central through-hole. The housing of the slave cylinder is formed, for example, of a plastic material. A preferred embodiment of the slave cylinder is characterized in that at the end remote from the actuating bearing of the anti-contamination device, an annular sealing element is provided, which conforms to the housing of the slave cylinder. As a result, it is reliably prevented in a simple manner that foreign particles enter into the slave cylinder between the end of the dirt protection device facing away from the actuating bearing and the housing. In this case, the annular sealing element, at least partially, advantageously biased by a preload against the housing of the slave cylinder.

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 remote from the actuating bearing of the anti-contamination device. The sealing collar is preferably connected in one piece with the dirt protection device. The sealing collar can protrude from the dirt protection device in the axial direction before assembly. During assembly, the sealing collar is preferred wise angled substantially at right angles radially inwardly of the pollution control device. In this case, the angled sealing collar is advantageously acted upon by an end turn of the preload spring. As a result, the dirt protection device can be securely held on the housing of the slave cylinder during operation of the slave cylinder, without it being possible for foreign particles to reach the slave cylinder at this point.

A further preferred embodiment of the slave cylinder is characterized in that the annular sealing element is clamped in the mounted state between an end turn of a preload spring and the housing of the slave cylinder. As a result, the preferably inwardly angled sealing collar of the annular sealing element is advantageously held in close contact with the housing of the slave cylinder. A further preferred embodiment of the slave cylinder is characterized in that the annular sealing element is provided at the end of hooks which are formed on the end remote from the actuating bearing of the anti-contamination device. Advantageously, the hooks engage housing receptacles of the housing of the slave cylinder to hold the mudguard in an axial direction against the housing. The housing receivers can be represented, for example, with a suitable mold by injection molding. For a stable attachment of the dirt protection device to the housing, at least three housing receivers are preferably provided for radially outwardly extending projections of the hooks on the housing. The number of housing receptacles on the housing need not match the number of radially outwardly extending projections. For example, it is possible for the antifouling device to have radially outwardly extending projections at one end over a full circumference through slots. The number of housing receptacles may be smaller than the number of radially outwardly extending projections. However, it is also possible in principle that the number of radially outwardly extending projections is smaller than the number of housing receptacles. Of course, the number of radially outwardly extending projections can also coincide with the number of housing receptacles. The housing may also have only a single housing receptacle, if this for Example is carried out circumferentially in circumferential direction. Such a circumferential housing receptacle can be represented for example by a continuous web. Such a continuous web is preferably designed as a ring body. A further preferred embodiment of the slave cylinder is characterized in that slots are provided in the circumferential direction between the hooks, which are closed by membranes which are integrally connected to the annular sealing element. Sufficient movement for the hooks can be represented by slots between the hooks. However, the slots may allow undesirable passage of air

Foreign particles. For this purpose, the slots or recesses are closed by the membranes. However, the membranes are advantageously made so thin and elastic that the hooks can spread during or after assembly.

A further preferred embodiment of the slave cylinder is characterized in that recesses are provided on the bearing-side end of the piston, which allow an exchange of air with the environment. Air exchange with the environment is necessary to ensure stable operation of the slave cylinder without damaging the bellows. However, the air exchange at the bearing end of the piston in view of an undesirable penetration of foreign particles in the slave cylinder, especially in comparison with an exchange of air at the end remote from the actuating bearing end of the dirt protection device, rather uncritical.

A further preferred embodiment of the slave cylinder is characterized in that the recesses on the bearing-side end of the piston represent Einwuhungen that allow an exchange of air between a central through hole of the actuating bearing and an annulus, which bounded below the actuating bearing of the pollution control device becomes.

This allows a simple way to operate the slave cylinder required air exchange with the environment, namely at a non-critical point in view of the unwanted intrusion of foreign particles in the slave cylinder. Another preferred embodiment of the slave cylinder is characterized in that the dirt protection device is designed as a bellows. The bellows is advantageously formed from an elastomeric plastic material or rubber material. By way of a collar and the hooks, the projections which project radially outward are preferably connected in one piece with folds of the bellows.

A further preferred embodiment of the slave cylinder is characterized in that the radially outwardly extending projections of the

Dirt device are provided on hooks. The hooks are preferably distributed uniformly over a circumference at the end of the dirt protection device.

As a result, the manufacture and assembly of the pollution control device are simplified.

A further preferred embodiment of the slave cylinder is characterized in that the hooks emanate from a collar which rests against a web which limits the housing receptacle or a plurality of housing receptacles. The web can be interrupted in the circumferential direction, that is, the web is not necessarily running circumferentially. The web is, for example by connecting straps, integrally connected to a ring body of the housing of the slave cylinder. The housing receivers are then bounded circumferentially by the connecting straps.

A further preferred embodiment of the slave cylinder is characterized in that the housing receptacles in the axial direction have effective retaining edges for the radially outwardly extending projections of the dirt protection device. The retaining edges are preferably provided radially inwardly of the web in the region of the housing receptacles. This allows a barb-like engagement of the radially outwardly extending projections into the housing receivers. Due to the holding edges which are effective in the axial direction, the dirt protection device with the radially outwardly extending projections is held stably on the housing of the slave cylinder.

A further preferred embodiment of the slave cylinder is characterized in that the radially outwardly extending projections by a Preload spring are biased radially outward. The hooks with the radially outwardly extending projections are limitedly flexible or elastically deformable for assembly purposes. The hooks with the radially outwardly extending projections may be designed as snap hooks. In the embodiment as a snap hook snap the radially outwardly extending projections of the dirt protection device during assembly advantageous in the housing receivers. When conducted in the context of the present invention investigations and experiments has been found that a preferably designed as a helical compression spring preload spring can be used to particular advantage to hold the dirt protection device to the housing of the slave cylinder. The preferably designed as a helical compression spring preload spring is in the slave cylinder, for example, to bias a bearing, in particular a release bearing, away from the slave cylinder for a clutch in the axial direction. Due to the additional use of the preload spring for attaching the dirt protection device on the housing, the preload spring gets a double function. This provides in particular the advantage that no additional component is needed for stable attachment of the anti-contamination 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 rests radially inward on the projections extending radially outward. An outer diameter of the at least one end turn of the preload spring is advantageously slightly larger than an inner diameter of the end of the dirt protection device with the radially outwardly extending projections. As a result, it is achieved in a simple manner that the radially outwardly extending projections are pressed radially outwards into the housing receptacles after the assembly of the dirt protection device by the preload spring. A contact region for the at least one end turn of the preload spring on the dirt protection device is preferably designed as a bevel. This simplifies the assembly of the preload spring. Depending on the design of the preload spring, more than one end turn or one end turn and one further turn of the preload spring can come to rest on the projections extending radially outwards. By Vorlastfeder a mounting force is exerted on the radially outwardly extending projections on the one hand. In addition, by the preload spring advantageously a holding force on the in the hous- Sea scenes located projections of the anti-contamination device are exercised to keep the anti-dust device particularly firm or stable to the housing. Another preferred embodiment of the slave cylinder is characterized in that the end turn of the preload spring is disposed in an annulus bounded radially inward by a cylinder wall and radially outward from the end of the debris guard having the radially outwardly extending projections received in the housings intervention. The cylinder wall is provided, for example, on the outside of an outer cylinder of the slave cylinder. The slave cylinder designed as a concentric slave cylinder comprises an inner cylinder concentrically or coaxially with the outer cylinder. The inner cylinder limits the above-described central through hole for performing a transmission shaft. Between the inner cylinder and the outer cylinder, an annular space is formed, which serves to guide a slave piston. The concentric slave cylinder thus comprises two coaxially or concentrically arranged annular spaces. The radially outer annular space constitutes an axial stop for the end turn of the preload spring. The housing receptacles extend from the annular space substantially radially outward.

The invention further relates to a dirt protection device, a piston and / or a housing for a previously described slave cylinder. The parts mentioned are separately tradable. Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, various embodiments are described in detail. Show it:

1 shows a slave cylinder with a housing in which a piston is guided back and forth movably, and with a dirt protection device which is attached at one end to an actuating bearing, in longitudinal section;

Figure 2 is a perspective view of the actuation bearing remote from the end of the dirt protection device; FIG. 3 a longitudinal section through the dirt protection device;

Figure 4 is an enlarged view of a detail IV of Figure 2; Figure 5 is an enlarged view of a detail V of Figure 1; Figure 6 is a perspective view of the piston; and FIG. 7 shows an enlarged illustration of a detail VII from FIG. 1.

In Figure 1, a slave cylinder 20 is shown with a housing 25 in longitudinal section. The housing 25 of the slave cylinder 20 comprises an inner cylinder 21 and an outer cylinder 22. The inner cylinder 21 defines radially inwardly a central through hole 28, which serves for example for performing a transmission shaft.

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

A web 30, which is provided radially on the outside of the housing 25, defines an annular space 45, which is 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 in FIG. 1 is bounded below by the annular body 26 of the housing 25.

Radially outward, the annular space 45 is bounded by the web 30. The web 30 is integrally connected via connecting straps 27 with the annular body 26 of the housing 25. The web with the connecting straps 27 is used to represent unspecified in Figure 1 housing receptacles on the housing 25. The housing receptacles are used respectively for receiving projections 15, 17 which are formed at the end of hook 1 1 to 14. In Figure 2 it can be seen that at the end facing away from the actuating bearing 64 of the dirt protection device 1 a plurality of hooks 1 1 to 14 are formed, on each of which a projection 15, 17 projects radially outward. The unspecified housing receptacles of the housing 25 each serve to receive one of the projections 15, 17 of the hooks 1 1 to 14.

The dirt protection device 1 is designed as a bellows 3. The bellows 3 is formed of an elastomeric rubber material and equipped with folds 5. An upper end 8 of the bellows 3 in FIG. 1 is associated with an actuating bearing 64, which is also referred to as a release bearing. At a lower end 10 in FIG. 1 of the dirt protection device 1, the hooks (11 to 14 in FIG. 2) are formed.

At the free ends of the hooks 1 1 to 14 each have a radially outwardly extending projection 15, 17 is formed. At the end 10 of the bellows 3, a total of eighteen hooks are formed, each having a projection extending radially outward. The hooks 1 1 to 14 are arranged distributed uniformly in the circumferential direction. Between two hooks 1 1, 12, a slot 18 is provided in each case. The slave cylinder 20 includes a preload spring 40, which is designed as a helical compression spring. An end turn 44 at the lower end of the preload spring 40 is assigned to the end 64 of the bellows 3 facing away from the actuation bearing 64. The bellows 3 has at its end 10 a collar 50. The collar 50 extends radially outward and rests on the web 30 of the housing 25. The collar 50 is integrally connected to the pleats 5 of the bellows 3.

From the collar 50, the hook 1 1 extends obliquely downwards. About the hook 1 1, the projection 15 is integrally connected to the collar 50. The end turn 44 of the preload spring 40 is in contact with the hook 1 1 of the bellows. 3

In the assembled state, the end turn 44 of the preload spring 40 is in abutment against the annular body 26 of the housing 25. By the end turn 44 of the preload spring 40, the projections 15, 17 at the ends of the hooks 1 1 to 14 pressed radially outward. The hooks 1 1 to 14 at the end 10 of the bellows 3 are moved in the assembly of the preload spring 40 by the end turn 44 outwardly against the web 30 so that the radially outwardly extending projections 15, 17 at the ends of the hook 1 to 14 are pressed into the housing receptacles. In this case, the projections 15 hooked barb-like manner on a retaining edge of the web 30th

By a suitable biasing force of the end turn 44 of the preload spring 40 radially outward, the hooks 1 1 to 14 are held stable with the projections 15 in the housing receptacles. By barb-like hooking the bellows 3 is held in the axial direction fixed to the housing 25.

The slave cylinder 20 further includes a piston 60. The piston 60 is guided with a U-ring seal 62 in the annular space 24. The annular space 24 represents a hydraulic pressure chamber of the slave cylinder 20. From its position shown in FIG. 1, the piston 60 can be moved downwards.

The bellows 3 is disposed outside an interface 65 between the piston 60 and the housing 25. This prevents in a simple manner that dirt, for example in the form of foreign particles, does not reach the interface 65 in an undesired manner. Therefore, the bellows 3 is also referred to as a dirt protection device 1.

The bellows 3 is mounted with its in Figure 1 upper end 8 radially outward on the actuating bearing 64. The actuating bearing 64 comprises a plurality of individual parts, such as rolling elements, which are designed as balls. Radially inside, the actuating bearing 64 rests on the upper end of the piston 60 in FIG. An annular space 66 is bounded radially inwardly by the piston 60 and radially outward by the bellows 3. The annular space 66 is limited in Figure 1 upwards of the actuating bearing 64. In FIGS. 2 and 3, it can be seen that an annular sealing element 70 is formed at the end 10 of the bellows 3. The annular sealing element 70 comprises a sealing collar 71, which is integrally connected to the projections 15, 17 on the hook 1 1 to 14. The sealing collar 71 is integrally connected to membranes 73, which close the slots 18 between each two adjacent hooks 12, 13. The membranes 73 have substantially the same thickness as the sealing collar 71. In FIG. 3, it is illustrated by a circle II that the bellows 3 has a continuously closed inner surface axially below the collar 50.

In the enlarged view of Figure 4 it can be seen that the membrane 73 completely fills the slot 18 between the hooks 12 and 13. Due to the smaller thickness of the membrane 73 in comparison to the thickness of the Haken12, 13 results between the hooks 12, 13 from recess 72. By an arrow 74 is indicated in Figure 4 that the membrane 73 an undesirable ingress of air from the environment in prevents the annulus (45 in Figure 1).

In Figure 5 it can be seen that the sealing collar 71 is clamped in the assembled state of Nehmerzy- Linders between the end turn 44 of the preload spring and the annular body 26 of the housing. By arrows 75 and 76 is indicated in Figure 5 that an exchange of air with the environment through the sealing collar 71 in combination with the diaphragm 73 shown in Figure 4 at the lower end 10 of the bellows 3 is reliably prevented.

To ensure proper operation of the slave cylinder 20, but sufficient air exchange between the annulus radially within the bellows 3 and the environment is necessary. According to one essential aspect of the invention, this 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 normally not critical in the installed state of the slave cylinder 20 in view of the unwanted ingress of dirt, in particular of foreign particles. In addition, the effect of centrifugal forces on an air flow at the upper end of the piston 60 promotes advantageous removal of dirt, in particular foreign particles.

FIG. 6 shows that the piston 60 has recesses 77 at its end facing the actuating bearing (64 in FIG. 1). The piston 60 comprises a total eight recesses 77 which are evenly distributed over a circumference of the piston 60 at its upper end. The recesses 77 represent shoeing 78, which, as indicated in Figure 7 by a double arrow 79, allow a desired exchange of air between the annular space 66 and the environment. The entry or exit of air takes place in the region of a central through-hole 80 in the actuating bearing 64.

LIST OF REFERENCE NUMBERS

I protection device

3 bellows

5 folds

8 end

10 end

I i hook

12 hooks

13 hooks

14 hooks

15 advantage

17 lead

18 slot

20 slave cylinders

21 inner cylinder

22 outer cylinder

23 cylinder wall

24 annulus

25 housing

26 ring body

27 connection tab

28 central through hole

30 footbridge

40 preload spring

44 final turn

45 annulus

50 fret

60 pistons

62 U-ring seal

64 actuation bearings

65 interface Annular space annular sealing element sealing collar

recess

membrane

arrow

recess

Einschuhung

double arrow

central through hole

Claims

claims

1 . Slave cylinder (20) having a housing (25) in which a piston (60) is guided back and forth between a rest position and a working position, wherein an interface (65) between the piston (60) and the housing (25) radially is surrounded on the outside by a dirt protection device (1), wherein an actuation bearing (64) is attached to a bearing end of the piston (60), characterized in that the slave cylinder (20) faces away from the actuation bearing (64) (10) Dirt guard (1) is sealed from the environment to prevent an exchange of air with the environment at this point.

2. slave cylinder according to claim 1, characterized in that on the actuating bearing (64) remote from the end (10) of the dirt device (1) an annular sealing element (70) is provided, which extends to the housing (25) of the slave cylinder (20). snugly.

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

4. slave cylinder according to claim 2 or 3, characterized in that the annular sealing element (70) in the assembled state between an end turn (44) of a preload spring (40) and the housing (25) of the slave cylinder (20) is clamped.

5. slave cylinder according to one of claims 2 to 4, characterized in that the annular sealing element (70) at the end of hooks (1 1 -14) is provided, which at the actuating bearing (64) facing away from the end (10) of the pollution control device ( 1) are formed.

6. slave cylinder according to claim 5, characterized in that in the circumferential direction between the hooks (12, 13) slots (18) are provided, which are closed by membranes (73) which are integrally connected to the annular sealing element (70) ,

7. slave cylinder according to one of the preceding claims, characterized in that on the bearing-side end of the piston (60) recesses (77) are provided which allow an exchange of air with the environment.

8. A slave cylinder according to claim 7, characterized in that the recesses (77) at the bearing end of the piston spikes (78) represent an exchange of air between a central through hole (80) of the actuating bearing (64) and an annulus (66) which is bounded below the actuating bearing (64) of the dirt protection device (1).

9. slave cylinder according to one of the preceding claims, characterized in that the dirt protection device (1) is designed as a bellows (3).

10. dirt protection device (1), piston (60) and / or housing (25) for a slave cylinder (20) according to one of the preceding claims.