Master cylinder with stop lugs and reinforcement ribs prepared for bayonet connection; and clutch

Abstract

Master cylinder (1) for a clutch actuation system of a motor vehicle, comprising a housing (2) and a piston (3) arranged such that it can be displaced relative to the housing (2), wherein at least one stop lug (5) is arranged and shaped on a radial outer side (4) of the housing (2) in such a way as to cooperate with a plate region (7) fixed to the vehicle frame to form a bayonet connection (6), and wherein the at least one stop lug (5) is reinforced by means of a reinforcing rib (8, 9), characterized in that the at least one stop lug (5) widens outwards in its extension from the outer side (4) of the housing (2) in the radial direction, wherein the at least one stop lug (5) widens radially outwards in a funnel shape when viewed in cross-section.

Description

[0001] The invention relates to a master cylinder for a clutch actuation system of a motor vehicle, such as a car, truck, bus, or other commercial vehicle, comprising a housing and a piston arranged displaceably relative to the housing. At least one stop lug (extending within a limited circumferential region) is arranged and shaped on a radial outer side / outer circumferential side of the housing in such a way as to cooperate with a plate region fixed to the vehicle / vehicle frame to form a bayonet connection, and the at least one stop lug is reinforced by means of a reinforcing rib. Furthermore, the invention relates to a clutch for a drive train of a motor vehicle, comprising a clutch actuation system having the master cylinder.

[0002] Master cylinders of this type are already well known in the art. For example, DE 10 2010 052 589 A1 discloses a special method for attaching a master cylinder to a vehicle wall using a bayonet-type connection.

[0003] It is therefore already known in principle to provide elevations on the housing of the master cylinder to form a bayonet lock / bayonet connection. However, a disadvantage of previous designs has been found: due to the relatively material-intensive design of the stop lug on the outside of the housing, undesirable deformations can occur during the primary forming process of the housing. Due to the previously implemented injection-molded stop lugs in the form of elevations on the outside, the resulting material thickening can lead to locally varying shrinkage behavior of the housing during curing after the primary forming process. This material thickening also creates a type of notch effect during operation of the master cylinder, which causes local stress peaks.This can, in turn, cause waviness on the inner circumferential side of the housing, which serves to guide the piston, which in turn has adverse effects on the piston. DE 101 57 264 A1 discloses a master cylinder with a stop lug that extends radially outward from the outside of the housing.

[0004] It is therefore an object of the present invention to eliminate the disadvantages known from the prior art and, in particular, to provide a master cylinder which requires as little reworking as possible and which ensures operational reliability over the longest possible service life.

[0005] This is achieved according to the invention in that the at least one stop lug widens in its extension from the outside of the housing in the radial direction outwards / increases in its thickness.

[0006] This provides a geometry of the stop nose that causes the lowest possible stress peaks in the housing during operation and has the least possible influence on the distortion behavior of the housing during production.

[0007] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0008] It is particularly advantageous if the housing of the master cylinder is molded from a plastic material, more preferably a polyamide, more preferably a PA66, in particular a PA66-GF43. The stop lug, which is formed integrally with the housing, is preferably made of the same material and is an integral part of the housing. This not only ensures a particularly rigid / stable construction for the housing, but also allows the master cylinder to be manufactured cost-effectively using an injection molding process.

[0009] According to the invention, the at least one stop lug, viewed in cross section, widens radially outwards in a funnel shape (from the outside of the housing).

[0010] The at least one stop lug advantageously borders, viewed in the axial direction, an annular disc region on the outside of the housing. This further increases the rigidity of the stop lug.

[0011] If the at least one stop lug is supported by means of a first reinforcing rib (extending in the axial direction) towards a first axial side, the stop lug is further reinforced.

[0012] In this context, it is further advantageous if the at least one stop lug is supported towards the first axial side by means of several, for example by means of two, first reinforcing ribs extending in the axial direction.

[0013] In order to further facilitate production and to reduce or even avoid rework, it is also advantageous if the at least one stop lug (preferably over the disc area) is supported towards a second axial side by means of a second reinforcing rib (extending in the axial direction).

[0014] In this regard, it is again advantageous if the at least one stop lug is supported towards the second axial side by means of several, for example two or three, second reinforcing ribs extending in the axial direction.

[0015] The plurality of reinforcing ribs are mounted particularly stably when the first reinforcing ribs and / or the second reinforcing ribs each extend radially outwardly from a common base area on the outside of the housing.

[0016] It is also advantageous if several, such as two, three, or four, stop lugs are arranged circumferentially spaced from each other. This further optimizes the bayonet connection.

[0017] Furthermore, the invention relates to a clutch for a drive train of a motor vehicle, with the master cylinder according to the invention according to at least one of the previously described embodiments, wherein the master cylinder is in turn provided in a clutch actuation system of the clutch.

[0018] In other words, the invention thus provides a master cylinder with a bayonet connection and reinforcing ribs. It is proposed to provide additional reinforcing ribs on the master cylinder so that less material is used during injection molding and thus prevent any seal damage. The master cylinder can either be connected to a flange via a bayonet connection, which in turn is connected to the bulkhead via a screw connection, or alternatively, it can be connected directly to the bulkhead via the bayonet connection.

[0019] The invention will now be explained in more detail below with reference to figures.

[0020] They show: Fig. 1 is a longitudinal sectional view of a master cylinder according to the invention, wherein in an upper half of the longitudinal section the master cylinder is shown in an extended position of the piston and in a lower half in a retracted position of the piston, and wherein the master cylinder is already attached to a plate area fixed to the vehicle frame, Fig. 2 a detailed view of the Fig. 1 shown master cylinder in an area in which the formation of a stop lug attached to a housing of the master cylinder and its support by means of reinforcing ribs can be clearly seen, Fig. 3 a detailed cross-sectional view of the housing of the master cylinder of the Fig. 1 and Fig. 2 in the area of ​​the stop lug along the Fig. 2 section line marked “III-III”, and Fig. 4 a perspective view of the master cylinder according to the Fig. 1 to 3, whereby the reinforcing ribs reinforcing the stop nose can be seen in a sub-illustration.

[0021] The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals. which is manufactured with particularly lightweight and cost-effective materials, on the other hand

[0022] In Fig. 1, a master cylinder 1 according to the invention is particularly clearly visible in its basic structure. The master cylinder 1 is typically a component of a clutch actuation system of a clutch (not shown further here for the sake of clarity), in the form of a friction clutch, of a drive train of a motor vehicle.

[0023] The master cylinder 1 is designed as a hydraulic master cylinder. The master cylinder 1 has a housing 2 forming a cylindrical outer wall 14. A piston 3 of the master cylinder 1 is slidably guided within the outer wall 14, wherein the piston 3 encloses a pressure chamber 15 with the housing 2 / the outer wall 14. Two seals 20, 21 are provided on the piston 3 to seal the pressure chamber 15 from the environment. The two seals 20, 21 are offset / spaced apart from one another in the axial direction. The first seal 20 serves as the primary seal, the second seal 21 as the secondary seal. Depending on the position of the piston 3, a hydraulic path leading to a slave cylinder can be pressurized. A piston rod 16 is rigidly coupled to the piston 3 and is typically further coupled for movement to a clutch pedal.

[0024] To secure the housing 2, at least one stop lug 5 is provided on a radial outer side 4 of the cylindrical outer wall 14, i.e., on a radial outer side 4 of the housing 2. A total of several stop lugs 5 are provided on the housing / on the outer side 4, distributed in the circumferential direction. The stop lugs 5 are arranged such that the housing 2 is prepared, in the mounted position of the master cylinder 1, to form a bayonet connection 6 with a plate area 7 fixed to the vehicle frame, as is also shown in Fig. 2 is implemented. The plate region 7 fixed to the vehicle frame is, for example, a bulkhead of the vehicle directly or, particularly preferably, a disc-shaped mounting plate which is fastened in a separate assembly step to the bulkhead or another region of the motor vehicle fixed to the vehicle frame, preferably by means of a screw connection.

[0025] To form the bayonet connection 6, the housing 2 has, as shown in Fig. 4, a disc region 10. The housing 2 has a flange region 18 offset from the disc region 10 by a certain axial distance along a longitudinal axis 17 of the piston 3 / the housing 2. The flange region 18 extends further outwards in the radial direction than the disc region 10. A receiving groove 19 which forms between the flange region and the disc region 10 and which runs in the circumferential direction serves in the fastened state according to Fig. 2 for receiving the plate area 7. As support elements for the bayonet connection 6 / the bayonet lock, the stop lugs 5 are provided on certain peripheral areas of the housing 2, as is particularly shown in Fig. 4. Each of the stop lugs 5 forms a substantially, as shown in Fig.3, a plate-shaped region widens in a funnel-shaped manner radially outward from the outer side 4. Thus, each stop lug 5 forms a thinner region at its attachment area on the outer side 4 than in a thickened region offset radially outward.

[0026] Each stop lug 5 borders the disk area 10 in the axial direction. Towards a first axial side 11, the respective stop lug 5 is supported in the axial direction by means of two first reinforcing ribs 8. The first reinforcing ribs 8 extend parallel to one another in the axial direction. Both first reinforcing ribs 8 are anchored together in a common first base area 13a on the outer side 4 of the housing 2 / connected to it. Additional second reinforcing ribs 9 adjoin this disk area 10 on a side of the disk area 10 facing away from the first reinforcing ribs 8. A total of three reinforcing ribs 9 are provided for each stop lug 5. The second reinforcing ribs 9 serve to axially support the disk area 10 and thus indirectly to support the stop lug 5 towards a second axial side 12 facing away from the first axial side.The second reinforcing ribs 9 also form a common base region 13b, which is anchored to the outer side 4. The reinforcing ribs 8, 9 and the stop lugs 5 are all manufactured as one piece with the housing 2, which is made of a plastic material.

[0027] In other words, the invention implements a special bayonet design, with the proportion / amount of material at the bayonet connection being reduced. Additionally, stiffening ribs / reinforcing ribs 8, 9 are provided. List of reference symbols 1 master cylinder 2 housings 3 pistons 4 Outside 5 Stop lug 6 bayonet connection 7 Plate area 8 first reinforcing rib 9 second reinforcing rib 10 disc area 11 first axial side 12 second axial side 13a Base area of ​​the first reinforcing rib 13b Base area of ​​the second reinforcing rib 14 Outer wall 15 Printing room 16 Piston rod 17 Longitudinal axis 18 Flange area 19 Recording groove

Claims

[1] Master cylinder (1) for a clutch actuation system of a motor vehicle, comprising a housing (2) and a piston (3) arranged to be displaceable relative to the housing (2), wherein at least one stop lug (5) is arranged and shaped on a radial outer surface (4) of the housing (2) in such a way as to cooperate with a plate area (7) fixed to the vehicle frame to form a bayonet connection (6), and wherein the at least one stop lug (5) is reinforced by means of a reinforcing rib (8, 9), characterized by , that the at least one stop nose (5) extends radially outwards from the outside (4) of the housing (2), wherein the at least one stop nose (5) extends radially outwards in a funnel shape when viewed in cross-section. [2] Master cylinder (1) according to claim 1, characterized by, that at least one stop nose (5) connects in an axial direction to an annular disk area (10) on the outside (4) of the housing (2). [3] Master cylinder (1) according to one of claims 1 to 2, characterized by , that at least one stop nose (5) is supported towards a first axial side (11) by means of a first reinforcing rib (8). [4] Master cylinder (1) according to claim 2, characterized by , that at least one stop nose (5) is supported towards the first axial side (11) by means of several first reinforcing ribs (8). [5] Master cylinder (1) according to any one of claims 1 to 4, characterized by , that at least one stop nose (5) is supported towards a second axial side (12) by means of a second reinforcing rib (9). [6] Master cylinder (1) according to claim 5, characterized by, that at least one stop nose (5) is supported towards the second axial side (12) by means of several second reinforcing ribs (9). [7] Master cylinder (1) according to claim 4 or 6, characterized by , that the first reinforcing ribs (8) and / or the second reinforcing ribs (9) extend radially outwards from a common base area (13a, 13b) on the outside (4) of the housing (2). [8] Master cylinder (1) according to any one of claims 1 to 7, characterized by , that several stop lugs (5) are arranged spaced apart from each other in the circumferential direction. [9] Clutch for a drive train of a motor vehicle, comprising a clutch actuation system comprising a master cylinder (1) according to any one of claims 1 to 8.

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