WO2008086763A1

WO2008086763A1 - Slave cylinder

Info

Publication number: WO2008086763A1
Application number: PCT/DE2007/002273
Authority: WO
Inventors: Mario Lombardo; Edgar Hummel; Roland Welter; Wolfgang Haas
Original assignee: Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority date: 2007-01-15
Filing date: 2007-12-17
Publication date: 2008-07-24
Also published as: DE102008057957C5; DE112007003205A5; DE102008057957B4

Abstract

The invention relates to a slave cylinder which is arranged concentrically about a transmission input shaft, in a hydraulic system for activating a clutch with a guide sleeve (2) which is manufactured from plastic and on whose lateral surface a piston (1) is axially movable. In order to form a stop (5, 9) at the clutch end of the guide sleeve, which stop (5, 9) at the same time carries out the function of providing captive attachment an which withstands a tearing-off force of more than 1000 N, said stop (5, 9) is embodied as a sleeve with a collar (5a, 9a) wherein the collar bears against the end face of the guide sleeve, and the sleeve is connected thereto in its interior in a positively locking fashion.

Description

slave cylinder

The invention relates to a slave cylinder in a hydraulic path for clutch actuation, which is arranged concentrically around a transmission input shaft, with a guide sleeve made of plastic, on the lateral surface up to a stop a piston axially movable to, in the form of a locking ring on the coupling end of the guide sleeve is inserted and protrudes radially beyond the cladding.

DE 20 380 270 U1 is known from the prior art, which has a slave cylinder arranged around a transmission input shaft with a guide sleeve made of plastic, on which a piston is arranged whose axial path in the direction of the coupling ends at a stop. This stop serves on the one hand to limit the way and as a safeguard against the loss of the piston and the release bearing in the disassembled state of the clutch during transport of the slave cylinder. The executed as a stop ring stop is attached to the front side of the guide sleeve by pushing or pushing in the axial direction in a provided on the end face of the guide sleeve circumferential groove. In this case, the groove is formed so that the correspondingly formed stop ring can engage in the intended undercuts.

DE 10 2005 045 813 A1 discloses a stop solution for a generic slave cylinder, in which the stop is formed from a securing ring. This is inserted into a provided on the coupling end of the guide sleeve, introduced into the lateral surface circumferential groove and protrudes beyond the diameter of the guide sleeve.

A disadvantage of the described solutions, however, is that these solutions only serve for attacks that withstand a pull-out force up to 1000 N. In addition, in these solutions, either the end face or the cross section of the plastic guide sleeve for attachment of the stop must be processed accordingly, whereby in the first case, the end face of the plastic guide sleeve must be greatly expanded and in the second case by their strength is reduced at the coupling end. It is therefore an object of the invention for a concentrically arranged around a transmission input shaft slave cylinder with a guide sleeve made of plastic, to realize at the kupplungsseitigem end a stop for a piston guided on this or a release bearing mounted on these, a pressure force or pull-out of more than 1000 N and is attached to the guide sleeve, without reducing their strength in this area.

This object is achieved with a slave cylinder with the features of claims 1 and 14. Instead of introducing the stop in the end face of the guide sleeve of this designed as a sleeve with collar stop is inserted into the coupling end of the guide sleeve. In this case, the projecting beyond the end face of the guide sleeve collar abuts against this. The attachment of the sleeve to the guide sleeve takes place in the interior by positive locking. The over the lateral surface of the guide sleeve protruding part of the collar serves as a limitation of Axialweges the piston.

In this way, the pull-out force generated by the axial force of the piston can be distributed to the projecting beyond the lateral surface of the guide sleeve, formed by the collar of the sleeve ring surface without a shearing force acting on the lateral surface of the guide sleeve. This makes it possible for this stop to withstand a pull-out force of more than 1000 N.

For securing the sleeve to the guide sleeve, the end of the sleeve facing away from the collar is advantageously designed to form a locking collar as a collar pointing radially outwards and provided with an undercut. This undercut forms in the radial direction a stop surface on the sleeve, via which a latching connection with the guide sleeve can be realized. However, this cost-effective design of the stop requires a higher force during assembly.

To reduce the assembly force when inserting the stop in the guide sleeve, in which both the guide sleeve stretched and the sleeve must be pressed radially together, the sleeve is provided with the outwardly directed collar with slots in the axial direction, which are distributed over the circumference , In this way, now consists of the body of the sleeve distributed over the circumference arranged latching hooks, by the elasticity thereof is increased. To prepare a positive connection with the stop, the guide sleeve is provided at its coupling end with an inwardly directed collar whose inner diameter is smaller than the actual inner diameter of the guide sleeve. This shoulder thus produced defines in the radial direction a stop surface on the guide sleeve, which can be contacted with the stop surface produced by the undercut.

To achieve a cost-effective production of the slave cylinder, it is particularly advantageous that the stop consists of an injection-moldable material, in particular of plastic.

However, it is also possible to produce the stop made of sheet metal. In this case, it is possible to keep the wall thickness of the sleeve as low as possible and to increase only the rigidity by increasing the wall thickness in the intended for connection to the guide sleeve portion of the sleeve to withstand a pull-out force above 1000 N. For this reason, the wall thickness is doubled in this area according to the invention by the end portion of the sleeve is folded inwards parallel to the lateral surface. To realize the connection, this thickened region of the sleeve surrounds the collar pulled inwards into the guide sleeve until it engages both its inner surface in the axial direction and its stop surface in the radial direction.

A further embodiment of the invention provides to prepare for the realization of the connection with the guide sleeve, that in order to increase the rigidity of the sleeve at the connection point in the radial direction, the wall thickness of the end portion is doubled by this is folded in the vertical direction inwards.

However, the connection between the sleeve insertable into the guide sleeve and the guide sleeve is produced by the sleeve initially engages around the inner diameter of the collar of the guide sleeve with its end and then applies the doubled in the radial direction wall thickness of the projecting end of the sleeve on the stop surface of the guide sleeve ,

Furthermore, the object of the invention with a slave cylinder with the features of claim 14 is achieved. In contrast to the preceding embodiments, this is a stop by a plug-in sleeve on the coupling end of the guide sleeve - A - formed a covenant, wherein the collar rests against the end face of the guide sleeve and in the interior of the guide sleeve cohesively, is connected by friction welding.

This is the stop, as well as the guide sleeve made of plastic. To produce the connection of the sleeve with the guide sleeve by means of friction welding, both the wall thickness of the sleeve and that of the guide sleeve in the connection area must be prepared accordingly in order to avoid an excess of material in this area. Therefore, the wall thickness of the sleeve is designed so that it tapers, starting from the collar, over at least two stages. Also, the wall thickness of the guide sleeve is stepped in the connection area at the coupling end, wherein the stages of both components are directed in opposite directions. In addition, the transition from the last stage of the wall thickness of the guide sleeve to the remaining wall thickness via a conical transition.

Further advantages and advantageous developments of the invention are the subject of the following figures, as well as their parts description.

Show it:

1 shows the end region of a slave cylinder arranged concentrically about a transmission input shaft with a stop according to the invention on the plastic guide sleeve in a sectional view,

FIG. 2 shows an embodiment of the slave cylinder shown in FIG. 1,

FIGS. 3a and 3b show the end region of the slave cylinder according to FIG. 1 in a sectional view with a stop according to the invention made of sheet metal, and its connection with the guide sleeve made of plastic in two process steps,

FIGS. 4a and 4b show the end region of the slave cylinder according to FIG. 1 in a sectional illustration with a further embodiment of the stop according to the invention made of sheet metal, and its connection with the guide sleeve made of plastic in two process steps, FIGS. 5a and 5b show a further embodiment of the end region of the slave cylinder according to FIG. 1 with a stop according to the invention inserted therein by means of friction welding in a sectional view.

FIGS. 1 to 5 show the end region of a slave cylinder 10 with a release bearing 3, which is arranged concentrically around a transmission input shaft, not shown, with a guide sleeve 2 made of plastic, on which a ring-shaped piston 1 up to a stop 5 formed as a sleeve 9 is axially movable and is sealed relative to the guide sleeve 2 by a sealing element 4 in a sectional view. In the description, the same reference numerals are used for identical components.

In the figure 1, the piston 1 is limited by a stop 5, which consists of a sleeve with a collar 5a and is inserted into the coupling-side end of the guide sleeve 2. In this case, the diameter of the collar 5a projects beyond the diameter of the guide sleeve 2 and abuts against it. The guide sleeve 2 has in this area a directed into the cylindrical interior waist 2a, so that a paragraph is formed to the adjoining inner wall. Through this paragraph, a stop surface 2a ^' on the collar 2a of the guide sleeve 2 is formed in the radial direction, which serves as a further contact surface with the sleeve 5.

The sleeve-shaped body of the stop 5 is therefore provided with a radially outwardly pointing hook-like collar defined as a locking collar 5g, which forms an undercut 5d to the rest of the lateral surface. When mounting the sleeve 5 with the guide sleeve 2 of the sleeve-shaped body is inserted into the interior of the guide sleeve 2, wherein the end portion 5e widens in the radial direction. As soon as the locking collar 5g has passed the inner diameter of the collar 2a, it engages behind the stop surface 2a ^' and the connection is completed.

To reduce the assembly force of the sleeve-shaped body is provided with slots 5c, so that instead of a latch collar 5g a plurality distributed over the circumference arranged snap hooks 5b result, as shown in Figure 2. With this embodiment of the sleeve-shaped body, the rigidity of the sleeve 5 is influenced to the extent that this end portion 5e becomes more elastic, which is advantageous in assembly in that case the guide sleeve 2 is stretched less radially, since in this process the snap hooks 5 b can be pressed radially inward, so as to come past the inner diameter of the federal 2ader guide sleeve 2. Subsequently, the connection of both parts is accomplished by the snap hooks 5 b snap behind the collar 2 a, wherein they rest with their undercut 5 d on the stop surface 2 a ^' .

Figures 3a to 4b show a stopper 5 according to the invention, which is formed from a thin-walled metal sleeve with a collar. The diameter of the collar 5a of this sleeve 5 is, as in the figures already described, larger than the diameter of the guide sleeve 2. The guide sleeve 2 is also provided with a directed towards the interior waistband 2a. To increase the rigidity of the sleeve 5 at the junction with the guide sleeve 2 whose wall thickness is doubled in the end region 5e either in the axial or in the radial direction.

FIGS. 3a and 3b show the mounting of the sleeve in the guide sleeve with simultaneous doubling of the wall thickness of the end region 5e. First, the sleeve 5 is inserted with its doubled end portion 5e in the guide sleeve 2 until it rests with its collar 5a at the end face. Subsequently, a forming tool 6 _{^ is} inserted into the cavity of the guide sleeve 2, which is formed so that it retracts (see Figure 3b) this reinforced end portion 5e of the sleeve 5 to the inner wall of the guide sleeve 2 and at the same time to the stop surface 2a ^' presses , so that a pull-out over 1000 N standhaltende connection arises.

In FIGS. 4a and 4b, in turn, a metal sleeve is shown as a stop 5. In contrast to the figures 3a and 3b is shown here that the assembly of the sleeve 5 on the guide sleeve 2 again takes place with the aid of a shaping tool 8, which is designed in this case in several parts. The shaping tool 8 consists of a sleeve-shaped base body slotted in the axial direction, into which a mandrel 7 provided in the front region with a conical outer contour 7a is inserted. After the collar 5 a rests against the end face of the guide sleeve 2, this sleeve 5 is pushed further with the shaping tool 8 into the interior of the guide sleeve 2. In this case, the mandrel 7 is not yet in the front, the pressure area. Since the forming tool 8 is provided in the front region with a circumferential groove 8a, which serves that the end of the sleeve 5 can be clamped in this, the end of the sleeve 5 is forcibly guided accordingly. Simultaneously with the axial movement of the shaping tool 8, the mandrel 7 is inserted into the Inner space of the guide sleeve pressed so that the ends of the forming tool 8 due to the conical lateral surface of the mandrel 7 can spread in the radial direction, wherein the end portion 5e of the sleeve 5 is pressed against the stop surface 2a ^'of the collar 2a. When retracting the forming tool 8, the end of the sleeve 5 is applied to the already applied to the stop surface 2a ^' wall of the sleeve 5 so that it doubles in this area. Thereafter, the mandrel 7 is also pulled out of the forming tool 8, whereby the ends of the forming tool 8 contract in the radial direction to its original position and the assembly is completed.

If the stop is made of plastic, there is the possibility of connecting it to the guide sleeve 2 by means of friction welding. From the figure 5a, the two components to be joined are visible. The executed as a sleeve 9 stop in turn has a cylindrical body with an end-side radially outwardly facing collar 9a, whose diameter is greater than the diameter of the guide sleeve 2. As well as the wall thickness of the cylindrical base body and the wall thickness of the guide sleeve 2 in the connecting region are prepared according to the friction welding process. Thus, the wall thickness of the sleeve 9, starting from its collar 9a, tapers to its end over two stages, so that a stepped jacket portion 9b is formed, while the wall thickness of the guide sleeve at the coupling end increases from a smaller wall thickness via a conical transition 2c.

For the assembly of both components, as shown in Figure 5a, the sleeve 9 is inserted into the guide sleeve 2 in rotation, whereby by this rotation frictional heat between the outer surface of the sleeve 9 and the inner surface of the guide sleeve 2 is formed, whereby both components in this area are materially connected be (see Figure 5b).

Although the solutions of a stop 5 for a slave cylinder 10 described with the aid of FIGS. 1 to 5 serve primarily to limit the axial travel of the piston slide 1; However, these also act as captive when transporting the slave cylinder 10th Reference list

1 piston

2 guide sleeve

2a fret

2a ^' radial stop surface

2c conical transition

3 release bearing

4 sealing element

5 stopper / sleeve

5a fret

5a ^' radial stop surface

5b snap hook

5c slots

5d undercut

5e end portion of the sleeve

5f hollow cylindrical basic body

5g Rastbund

6 shaping tool for holding element

6a conical bevel

7 mandrel for forming tool for holding element

7a conical outer contour

8 shaping tool for holding element

8a groove

9 stop sleeve θa collar

9b graduated jacket area

10 slave cylinders

Claims

claims

1. slave cylinder (10) in a hydraulic line for clutch actuation, which is arranged concentrically around a transmission input shaft, with a guide sleeve made of plastic (2), on the lateral surface up to a stop a piston (1) axially movable to the in shape a circlip on the coupling end of the guide sleeve (2) is inserted and protrudes radially beyond the cladding surface, characterized in that a stop (5) as a in the guide sleeve (2) insertable sleeve with a collar (5 a) is executed, wherein the collar (5a) bears against the coupling-side end face of the guide sleeve (2) and the sleeve (5) is connected in a form-fitting manner inside with the guide sleeve (2).

Second slave cylinder (10) according to claim 1, characterized in that the collar (5a) entgegengestzte the end of the sleeve (5) to form a latch collar (5g) as a radially outwardly pointing, provided with an undercut (5d) provided collar is.

3. slave cylinder (10) according to claim 1 and 2, characterized in that the formation of snap hooks (5 b) in the provided with the locking collar (5 g) sleeve (5) distributed over the circumference of slots (5 c) are introduced.

4. slave cylinder (10) according to claims 1 to 3, characterized in that the undercut (5d) in the radial direction forms a stop surface (5a ^' ).

5. slave cylinder (10) according to claim 1, characterized in that the guide sleeve (2) at its coupling end has an inwardly directed collar (2 a) whose inner diameter is smaller than the inner diameter of the guide sleeve (2), so that the Inner diameter generated paragraph in the radial direction defines a stop surface (2a ^' ).

6. slave cylinder (10) according to claims 4 and 5, characterized in that the stop surface (5a ^' ) of the stop (5) on the stop surface (2a ^' ) of the guide sleeve (2).

7. slave cylinder (10) according to claim 1, characterized in that the outer diameter of the collar (5a) of the stop (5) is greater than the outer diameter of the guide sleeve (2).

8. slave cylinder (10) according to claim 1, characterized in that the stop (5) made of an injection-moldable material, in particular made of plastic.

9. slave cylinder (10) according to claim 1 and 2, characterized in that for doubling the wall thickness, an end region (5e) of the sleeve (5) is folded inwards parallel to the lateral surface thereof.

10. slave cylinder (10) according to claim 1, 5 and 9, characterized in that the end region (5e) of the sleeve (5) engages around the inner diameter of the collar (2a) of the guide sleeve (2) and rests against the inner surface.

11. slave cylinder (10) according to claim 1, characterized in that a collar (5a) opposite portion of the sleeve (5) is folded to double the wall thickness in the radial direction in the vertical direction inwards.

12. slave cylinder (10) according to claim 1, 5 and 11, characterized in that the flared end portion (5e) of the sleeve (5) engages around the inner diameter of the collar (2a) of the guide sleeve (2) and at the stop surface (2a ^' ) applies.

13. slave cylinder (10) according to claim 1, characterized in that the stop (5) is made of sheet metal.

14 slave cylinder (10) in a hydraulic path for clutch actuation, which is arranged concentrically around a transmission input shaft, with a guide sleeve made of plastic (2), on the lateral surface up to a stop a piston (1) axially movable to the in shape a retaining ring on the coupling-side end of the guide sleeve (2) is inserted and radially projecting beyond the cladding surface, characterized in that a stop (9) as a sleeve in the guide sleeve (2) insertable with a collar (9 a) is executed, wherein the collar (9a) rests against the coupling-side end face of the guide sleeve (2) and the sleeve (9) is integrally connected to the guide sleeve (2) in the interior.

15. slave cylinder (10) according to claim 14, characterized in that in the axial direction, starting from the collar (9 a), the wall thickness of the sleeve (9) tapers over at least two stages.

16. slave cylinder (10) according to claim 15, characterized in that in the axial direction, starting from the coupling end, the wall thickness of the corresponding stage of the sleeve (9) adapted wall thickness of the guide sleeve (2) via a conical transition (2c) up to whose intended wall thickness increases.