DE102011088469A1 - Master cylinder for e.g. hydraulic clutch of vehicle, has pressure chamber sealed opposite to piston and housing by primary seal that is formed on side of intermediate ring, where intermediate ring is arranged between housing and piston - Google Patents

Abstract

The cylinder (1) has a housing (2) closed by a perspiration ring (5), and a pressure chamber (4) limited in a longitudinal bore (3) of the housing by an axially displaceable piston (6). The chamber is sealed opposite to the piston and the housing by a primary seal (7). The primary seal is formed on a side of an intermediate ring (8) spaced from the perspiration ring. The intermediate ring is arranged between the housing and the piston, and comprises a dovetail-shaped annular groove (9.1) in an end side. A secondary seal (10) is arranged in a radial recess (5.2) of the perspiration ring.

Description

The invention relates to a master cylinder for a hydraulic clutch or brake system of a vehicle according to the preamble of the first claim.

From the publication DE 10 2008 010 448 A1 a master cylinder for a hydraulic clutch or brake operation is known which comprises a closed by welding ring housing in which a piston is arranged axially movable by pressurization and sealed relative to the housing and the welding ring by means of seals, wherein the seals by a on the piston applied intermediate ring are axially spaced from each other. To avoid a dirt entry on the guide surface of the piston, the intermediate ring is centered radially free of play received on the inner diameter of the housing. The fact that the primary seal is arranged freely to the intermediate ring, the position of the primary seal in the assembly of the master cylinder is defined by several dimensions of the housing, intermediate ring and welding ring. As a result, a tolerance chain is given by which it can lead to a compression of the seal or a game of the seal in the installation space.

If a play of the primary seal in the installation space occurs due to the tolerance chain, the seal can move in the axial direction. This has, in addition to increased wear on the seal, also direct influence on the free travel (Schnüffelweg) of the master cylinder. Since this Leerweg is a functionally important feature, this should be adhered to as closely as possible.

If the seal is installed in a compressed state, it will lead to increased stresses together with the hydraulic operating pressure. This can lead to damage and thus failure of the master cylinder.

The object of the invention is to reduce the tolerance chain for the arrangement of the primary seal.

This object is achieved with a master cylinder having features of the first claim.

Advantageous embodiments emerge from the subclaims.

The master cylinder, which is used for a hydraulic clutch or brake system of a vehicle application, consists essentially of a closed by means of a welding ring housing, in the longitudinal bore a pressure chamber (primary pressure chamber) is limited by a piston axially displaceable when pressurized, wherein the pressure chamber is sealed relative to the piston and the housing by means of a primary seal and wherein the primary seal is disposed on the side spaced from the welding ring of an intermediate ring which is fixed to the housing between housing and piston in the housing, wherein the primary seal according to the invention is firmly connected to the intermediate ring.

This fixed connection of the primary seal to the intermediate ring ensures that the primary seal always bears against the intermediate ring. This can be dispensed with on the front side of the seal in the direction of the encoder housing on a so-called crown geometry, which was previously necessary for coarse positioning. A compression of the primary seal between the housing and intermediate ring or a gap between the seal and intermediate ring is now no longer possible due to the reduced tolerance chain.

Preferably, the primary seal is connected to the side remote from the welding ring end face of the intermediate ring.

The clipping or tying the primary seal in the intermediate ring is a particularly elegant and practical method. Alternatively, the primary seal can also be glued or vulcanized to the intermediate ring.

For clipping, these two components are axially connected by a special knotting geometry on the primary seal and on the intermediate ring of the clutch master cylinder. Thus, it can be prevented that the primary seal is installed compressed, or has a gap to the intermediate ring, whereby they could move.

For this purpose, the intermediate ring in its end face, for example, a substantially dovetail-shaped in cross-section annular groove, in which a corresponding annular projection on the end face of the primary seal, which points in the direction of the intermediate ring, einknüpfbar, so that the primary seal after Einknüpfen preferably under axial bias abuts the intermediate ring.

The intermediate ring is arranged fixed to the frame in the housing, wherein between a radial shoulder of the housing and a radially outwardly facing shoulder of the intermediate ring, an elastic element, for example in the manner of an O-ring is arranged, which by avoiding a tolerance gap between the seal and Intermediate ring is possible due to the attached seal. The elastic element serves to position the intermediate ring, which is especially true at Donor cylinders is important in which case and welding ring mechanically, z. B. are connected with pins, as are compensated by the elastic element component tolerances and thus a complex tuning of the tools and a precise axial tolerancing is no longer required.

The seal is thus neither compressed, nor is there a gap to the intermediate ring, since the intermediate ring is attached directly to the welding ring and rests against the facing end face of the welding ring.

The intermediate ring is connected to the housing or to the welding ring fixed to the housing.

Furthermore, a secondary seal is arranged in a radially inwardly directed intermediate ring-side recess of the welding ring, which serves to seal the secondary pressure chamber.

With the solution according to the invention, a master cylinder is provided with frame-fixed primary seal, which reduces the tolerance chain and thus a game or a compression of the primary seal is avoided in the installation space by the firm connection of primary seal and intermediate ring.

As a result, the life of the master cylinder is increased and ensures accurate compliance with the free travel.

The invention will be explained in more detail with reference to an embodiment and associated drawings.

Show it:

1 a longitudinal section of a master cylinder in the region of the primary seal and intermediate ring;

2 a longitudinal section, similar 1 but with an elastic element;

3 a longitudinal section through the joined components in the form of intermediate ring and primary seal;

4 the three-dimensional representation of the intermediate ring according to 3 ,

According to 1 and 2 points the master cylinder 1 a housing 2 in, in the longitudinal bore 3 a pressure room 4 is trained. The housing 2 is by means of a welding ring 5 closed, in which a piston 6 is arranged axially displaceable, which the pressure chamber 4 limited. The pressure room 4 is opposite to the outer diameter D6 of the piston 6 and the inner diameter d2 of the housing 2 by means of the intermediate primary seal 7 sealed. The primary seal 7 is by clipping or Einknüpfen firmly with an intermediate ring 8th connected, the axially to the assigning end face 5.1 of the welding ring 5 connects and radially between housing 2 and pistons 6 sits and with the case 6 is firmly connected to the frame. The primary seal 7 is with the intermediate ring 8th connected by tying.

The intermediate ring 8th points to it in his front page 8.1 moving towards the primary seal 7 has, in cross-section substantially dovetailed annular groove 9.1 on. In this frontal annular groove 9.1 engages a correspondingly formed annular projection 9.2 one axially moving towards the intermediate ring 8th pointing forehead 7.1 the primary seal 7 extends. After tying, the primary seal is located 7 preferably under axial bias with its front side 7.1 at the front 8.1 of the intermediate ring 8th at.

Next to the primary seal 7 is between the welding ring 5 and the intermediate ring 8th in a radially inwardly directed intermediate ring-side recess 5.2 of the welding ring 5 a secondary seal 10 arranged.

In contrast to 1 is, according to 2 , between an outwardly facing radial shoulder 2.1 of the housing 2 and a radially outwardly facing shoulder 8.2 of the intermediate ring 8th an elastic element 11 arranged in the form of an O-ring, through which axial tolerances of the welding ring 5 and the intermediate ring 8th be compensated.

The with the intermediate ring 8th joined primary seal 7 shows 3 in longitudinal section and 4 in the three-dimensional representation.

Out 3 can be seen as in the knotted state of the projection 9.2 the primary seal 7 in the frontal annular groove 9.1 of the intermediate ring 8th intervenes. Because of the annular groove 9.1 dovetailed and the projection 9.2 is designed to correspond, unintentional detachment of the primary seal 7 from the intermediate ring 8th prevented and it is a pre-assembly of the two components 7 and 8th possible.

From the three-dimensional representation it becomes clear that the intermediate ring 8th and the primary seal 7 act like a component or a structural unit in the assembled state.

According to non-illustrated embodiments, it is also possible to connect the primary seal otherwise with the intermediate ring, z. B. cohesively (gluing or welding), a 2- Component injection molding, by vulcanization etc.

LIST OF REFERENCE NUMBERS

1

Master cylinder

2

casing

2.1

radial shoulder of the housing

3

longitudinal bore

4

pressure chamber

5

weld ring

5.1

Front side of the welding ring

5.2

Recess of the welding ring

6

piston

7

primary seal

7.1

Front side of the primary seal

8th

intermediate ring

8.1

Front side of the intermediate ring

9

ring groove

10

secondary seal

11

Elastic element

d2

Inner diameter of the housing 2

D6

Outer diameter of the piston 6

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008010448 A1 [0002]

Claims (10)

Master cylinder ( 1 ) for a hydraulic clutch or brake system of a vehicle, consisting essentially of one with a welding ring ( 5 ) closed housing ( 2 ), in whose longitudinal bore ( 3 ) a pressure chamber ( 4 ) by an axially displaceable upon pressurization piston ( 6 ) is limited, wherein the pressure chamber ( 4 ) opposite the piston ( 6 ) and the housing ( 2 ) by means of a primary seal ( 7 ), the primary seal ( 7 ) on the welding ring ( 5 ) spaced side of an intermediate ring ( 8th ) between housing ( 2 ) and pistons ( 3 ), is arranged, characterized in that the primary seal ( 7 ) fixed to the intermediate ring ( 8th ) connected is. Master cylinder ( 1 ) according to claim 1, characterized in that the primary seal ( 7 ) with the welding ring ( 5 ) facing away from the front side ( 8.1 ) of the intermediate ring ( 8th ) connected is. Master cylinder ( 1 ) according to claim 1 or 2, characterized in that the primary seal ( 7 ) in the intermediate ring ( 8th ) is clipped / knotted. Master cylinder ( 1 ) according to one of claims 1 to 3, characterized in that the intermediate ring ( 8th ) in its front side ( 8.1 ) a cross-sectionally substantially dovetail-shaped annular groove ( 9.1 ) into which a corresponding annular projection ( 9.2 ) on the front side ( 7.1 ) of the primary seal ( 7 ) moving in the direction of the intermediate ring ( 8th ), is attachable. Master cylinder ( 1 ) according to one of claims 1 to 4, characterized in that the primary seal ( 7 ) after tying under axial prestress on the intermediate ring ( 8th ) is present. Master cylinder ( 1 ) according to one of claims 1 to 5, characterized in that the intermediate ring ( 8th ) fixed to the frame in the housing ( 2 ) is arranged. Master cylinder ( 1 ) according to one of claims 1 to 6, characterized in that between a radial shoulder ( 2.1 ) of the housing ( 2 ) and a radially outwardly facing shoulder ( 8.2 ) of the intermediate ring ( 8th ) an elastic element ( 11 ) is arranged. Master cylinder ( 1 ) according to one of claims 1 to 7, characterized in that the intermediate ring ( 8th ) on the facing end face ( 5.1 ) of the welding ring ( 5 ) is present. Master cylinder ( 1 ) according to one of claims 1 to 8, characterized in that the intermediate ring ( 8th ) with the housing ( 2 ) or with the welding ring ( 5 ) connected is. Master cylinder ( 1 ) according to one of claims 1 to 9, characterized in that in a radially inwardly directed intermediate ring-side recess ( 5.2 ) of the welding ring ( 5 ) a secondary seal ( 10 ) is arranged.

Images