Pressure tank for operating the friction clutch

Abstract

A pressure tank (16) is used to operate a friction clutch (12, 14), and is provided with a force introduction element (22) for introducing an operating force generated by an operating system and aligned in an axial direction, a pressure element (30) for fixing a pressure plate (32) of the friction clutch (12, 14), and a return spring (18) for moving the pressure element (30) to an initial position away from the pressure plate (32), wherein the return spring (18) is designed as a whole with the force introduction element (22) and the pressure element (30). By designing the return spring (18) as a whole in the pressure tank (16), the number of components and the installation cost can be reduced, thereby realizing the friction clutch (12, 14) with low manufacturing cost.

Description

Technical Field

[0001] The invention relates to a pressure tank, by means of which a friction clutch can be actuated directly—that is to say without a lever transmission ratio—via an operating system. Background Art

[0002] Figure 1 The known dual clutch 10 shown has a first friction clutch 12 and a second friction clutch 14, each of which is designed as a diaphragm clutch. In order to operate the respective friction clutches 12, 14, a pressure tank 16 that can be axially moved by an operating system is provided, which can be moved against the elastic force of an independent return spring 18 to close the assigned friction clutch 12, 14. In order to provide a return force when closing the assigned respective friction clutch 12, 14, the return spring 18 designed as a disc spring is compressed between the axially fixed support washer 20 and the pressure tank 18.

[0003] There is always a need to reduce the manufacturing costs of friction clutches. Summary of the invention

[0004] The object of the present invention is to demonstrate measures which allow the friction clutch to be produced cost-effectively.

[0005] This object is achieved according to the invention by a pressure tank having the features of claim 1. Advantageous embodiments of the invention are given in the dependent claims and in the following description, which can each represent aspects of the invention individually or in combination.

[0006] According to the present invention, a pressure tank for operating a friction clutch is provided with a force introduction element for introducing an operating force generated by an operating system and aligned in an axial direction, a clamping element for fixing a clamping plate of the friction clutch, and a return spring for moving the clamping element to an initial position away from the clamping plate, wherein the return spring is designed as a whole with the force introduction element and the clamping element.

[0007] Usually, the pressure tank is axially moved in the axial direction without an intermediate lever transmission ratio by an operating system, and the operating system has a piston that can extend in the axial direction of the friction clutch, so that the operating force introduced in particular radially inward can be transmitted axially outward to the clamping plate by the pressure tank to close the friction clutch. For this purpose, a force introduction element radially inward, especially located in the radial inner edge area of ​​the pressure tank, and a clamping element radially outward, especially located in the radial outer edge area of ​​the pressure tank can be provided. The force introduction element and the clamping element can be connected to each other through a disc-shaped middle area, and the shape of the disc-shaped middle area can be freely designed within a specific limit range. The pressure tank is preferably made of steel, which is basically rigid at low manufacturing costs except that it will undergo slight elastic deformation under the load of the introduced operating force. It is known that in order to transmit force between the force introduction element and the clamping element, there is no need to have a completely closed annular middle area in the circumferential direction, so a return spring can be formed by a disc body of the pressure tank that surrounds the force introduction element and the clamping element at the same time. It is also known that the space-saving restoring spring does not necessarily have to be formed by a disc spring, but can also be provided by an elastically deformable web which can be bent out of the material surrounding the disc body of the pressure tank. In particular, when the pressure tank has a greater material thickness than a typical disc spring to ensure that it is elastically deformed only to a negligible extent at the expected maximum operating force, an integral restoring spring in the form of an overhanging web can easily have suitable spring characteristics, whose spring characteristic curve has sufficient strength to match the spring characteristic curve of a separately arranged disc spring. By designing the restoring spring integrally in the pressure tank, the number of components and the installation expenditure can be reduced, thereby achieving a friction clutch with low manufacturing costs.

[0008] The return spring is designed in particular as a leaf spring. The return spring can thus be designed as a web having the thickness of the rest of the pressure tank material. With its flat side, the return spring can rest and / or bear against a component of the friction clutch that is immovable in the axial direction and undergo significant elastic bending in the direction of its surface normal. Thus, a load can be applied to the return spring designed as a single leaf spring in the manner of a bent beam, thereby avoiding local stress peaks and also avoiding changes in the spring characteristic curve of the return spring by partial plastic deformation. In this case, the longitudinal direction of the return spring can extend at least partially in the radial direction and / or in the tangential direction, so that the given design space ratios can be implemented particularly simply.

[0009] The return spring preferably protrudes from a disk body that can be produced by a stamping and forming process. The disk body that forms the pressure tank can be produced at low cost from sheet metal, wherein the disk body is stamped out of the sheet metal and then processed into the final shape by a non-cutting plastic forming process, in particular forging, deep drawing, bending, etc. In this case, the return spring, which is designed in particular to connect the leaf spring, can be separated from the surrounding material of the disk body by a separating seam in the stamping step and then bent out of the layer surrounding the return spring by plastic deformation in the forming step. The return spring thus protrudes from the surrounding material and is strong enough to assume the spring function.

[0010] It is particularly advantageous to arrange a plurality of return springs distributed in the circumferential direction. In this way, the elastic force acting on the return spring can be supported uniformly, thereby avoiding and / or reducing stress peaks in the corresponding return spring. In particular, at least three return springs are arranged, so that a three-point support can be achieved by the return springs.

[0011] The invention further relates to a friction clutch for connecting an engine shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission, with a top plate for introducing torque from the engine shaft, a pressure plate axially movable relative to the top plate, for pressing a friction plate connectable to the transmission input shaft between the top plate and the pressure plate in a friction fit, and a pressure tank designed and improved as described above, for pressing the pressure plate against the top plate when an operating force is introduced and for automatically canceling the pressure between the pressure plate and the top plate when no operating force is present. By designing the return spring integrally in the pressure tank, the number of components and the installation effort can be reduced, thereby realizing a friction clutch with low manufacturing costs.

[0012] In particular, a support washer is provided which is indirectly or directly connected to the top plate and cannot be moved in the axial direction, in particular designed as a clutch cover, wherein the return spring of the pressure tank is supported on the support washer. The support washer can be arranged in particular in the axial direction between the pressure plate and the pressure tank majority, wherein the support washer has a through hole for passing the pin provided by the corresponding pressure element, so that the pressure tank can reach the pressure plate with the pressure element behind the support washer through the pin passing through the support washer. As a result, the return spring can be pressed against the axial side of the support washer facing the pressure tank majority, and then the pressure tank is pressed back to the axial position corresponding to the friction clutch opening position when the operating force is no longer present. As an alternative, the support washer can also be positioned in the axial direction in the form of a clutch cover, so that the pressure tank is arranged in the axial direction between the support washer and the pressure plate. In this case, the return spring formed by the pressure tank can be hung in a protruding hook of the support washer on the side of the pressure tank facing away from the pressure plate, so that the pressure tank can be pressed back to the axial position corresponding to the friction clutch opening position by the return spring when the operating force is no longer present.

[0013] The preferred design of the return spring is that it is compressed in the axial direction when the pressure plate is moved toward the top plate to form a pressure, thereby avoiding the return spring from hanging on the support washer and simplifying the installation.

[0014] The invention further relates to a dual clutch for connecting an engine shaft of a motor vehicle engine to a first transmission input shaft and / or a second transmission input shaft of a motor vehicle transmission, which has a first friction clutch designed and improved as described above for connecting the engine shaft to the first transmission input shaft, and / or a second friction clutch designed and improved as described above for connecting the engine shaft to the second transmission input shaft. By integrating the return spring into the pressure tank of the corresponding friction clutch, the number of components and the installation cost can be reduced, thereby realizing a friction clutch with low manufacturing cost.

[0015] It is particularly advantageous to provide that the pressure tank return spring of the first friction clutch and the pressure tank return spring of the second friction clutch are directly or indirectly supported on the same component that cannot move axially, thereby reducing the number of components and the installation cost, thereby reducing the manufacturing cost.

[0016] In particular, it is provided that the first friction clutch and / or the second friction clutch is designed as a diaphragm clutch. This can save radial design space. In addition, the maximum torque to be transmitted can be easily set for the corresponding diaphragm clutch by the number of friction pairs in the corresponding diaphragm clutch. In addition, the friction clutch can be cooled by a coolant, in particular oil, and the reduction in the friction coefficient caused by the coolant can be easily compensated by increasing the number of friction pairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described exemplarily below based on advantageous embodiments with reference to the accompanying drawings, wherein the features described below can demonstrate aspects of the present invention individually or in combination.

[0018] Figure 1 : A schematic perspective sectional view of a part of a known dual clutch,

[0019] Figure 2 : a schematic perspective sectional view of a portion of the dual clutch according to the invention, and

[0020] Figure 3 : Figure 2 A schematic perspective cutaway view of a dual clutch pressure tank is shown. DETAILED DESCRIPTION

[0021] Figure 2 The double clutch 10 of the present invention shown in the figure has a first friction clutch 12 and a second friction clutch 14, which are each designed as a diaphragm clutch. In order to operate the corresponding friction clutches 12, 14, a pressure tank 16 that can be axially moved by the operating system is provided, and the pressure tank can be moved against the elastic force of the return spring 18 formed by the pressure tank 16 itself to close the assigned friction clutch 12, 14. In order to provide a return force when closing the relevant friction clutch 12, 14, the return spring 18 designed as a bent beam and / or a leaf spring is compressed between the axially fixed support washer 20 and the pressure tank 18.

[0022] Figure 3 The pressure tank 16 shown in the example in the figure has a force introduction element 22 in the radially inward direction, through which an actuating force directed in the axial direction can be introduced by a piston of an actuating device, for example a hydraulically extendable piston. The force introduction element 22 is connected via a disk-shaped but curved middle area 24 of a one-piece disk body 26 to a pin 28 extending in the axial direction, which pins each form a pressure element 30 at their protruding ends.

[0023] like Figure 2As shown, the pin 28 can be passed through the through hole of the support washer 20, so that the pressure element 30 can act on the pressure plate 32 of the respective friction clutch 12, 14 in order to close the friction clutch 12, 14. In the embodiment shown, the pressure plate 32 is formed by an axially outer steel plate, which can be pressed against an axially fixed top plate 36, which is formed, for example, by an outer friction plate carrier 34, so that a friction pair is produced between friction plates which are connected alternately to the outer friction plate carrier 34 and the inner friction plate carrier 38 in a rotationally fixed manner but are axially movable. The torque transmitted in the friction clutch 12, 14 can be further guided to the first transmission input shaft or the second transmission input shaft of the dual clutch transmission via the respective inner friction plate carrier 38. The support washer 20 can be connected to the top plate 36 in a rotationally fixed manner, and in the embodiment shown, for this purpose, the outer friction plate carrier 34 of the friction clutch 12, 14 can be inserted into the corresponding opening of the support washer 20 in a rotationally fixed manner. In order to introduce torque into the friction clutches 12 , 14 , it can be provided, for example, that the support disk 20 is coupled in a rotationally fixed manner to a flywheel 40 which is connected to a motor shaft of a motor vehicle engine.

[0024] like Figure 3 As shown, the return spring 18 protrudes integrally from the disk body 26 and is therefore also designed in one piece with the radially inner force introduction element 22 and the radially outer pressure element 30. For this purpose, the return spring 18 is plastically bent out of the material of the intermediate region 24 in the form of a connecting leaf spring and can be pressed directly or indirectly with the flat side against the support washer 20 when the friction clutch 12, 14 is closed and compressed to generate a spring force. If no operating force is introduced into the pressure tank 16, the spring force of the return spring 18 can press the pressure tank 16 into the open position of a friction clutch 12, 14, thereby making the friction clutch "normally open".

[0025] Reference numerals list

[0026] 10 Dual Clutch

[0027] 12 First friction clutch

[0028] 14 Second friction clutch

[0029] 16 Pressure tank

[0030] 18 Return spring

[0031] 20 Supporting spacer

[0032] 22 Force introduction element

[0033] 24 Middle Area

[0034] 26 disc body

[0035] 28 Pin

[0036] 30 Clamping element

[0037] 32 Clamping plate

[0038] 34 Outer friction plate bracket

[0039] 36 Top Plate

[0040] 38 Inner friction plate bracket

[0041] 40 Flywheel

Claims

1. A dual clutch for connecting an engine shaft of a motor vehicle engine to a first transmission input shaft and / or a second transmission input shaft of a motor vehicle transmission, comprising a first friction clutch (12) for connecting the engine shaft to the first transmission input shaft and a second friction clutch (14) for connecting the engine shaft to the second transmission input shaft, wherein: The second friction clutch (14) is arranged radially inside the first friction clutch (12) so as to at least partially overlap the first friction clutch (12) in the axial direction, wherein the first friction clutch (12) and the second friction clutch (14) respectively have: A top plate for introducing torque from the engine shaft, a clamping plate axially movable relative to the top plate, for pressing a friction plate connectable to the transmission input shaft between the top plate and the clamping plate in a friction fit manner, and A pressure tank, which is used to press the pressure plate against the top plate when an operating force is introduced and to automatically cancel the squeezing force between the pressure plate and the top plate when there is no operating force, the pressure tank having: a force introduction element for introducing an operating force generated by the operating system and aligned in the axial direction, a clamping element for fixing the top plate of the corresponding friction clutch, and a return spring for moving the pressure element into an initial position away from the pressure plate, wherein the return spring is designed as one piece with the force introduction element and the pressure element, The return spring of the pressure tank of the first friction clutch (12) and the return spring of the pressure tank of the second friction clutch (14) are directly or indirectly supported on the same axially non-movable component (20).

2. The dual clutch according to claim 1, characterized in that: The return spring is designed as a leaf spring.

3. The dual clutch according to claim 1 or 2, characterized in that: The return spring can protrude from a disk body which can be produced by a stamping and forming process.

4. The dual clutch according to claim 1 or 2, characterized in that: A plurality of return springs are distributed in the circumferential direction.

5. The dual clutch according to claim 1 or 2, characterized in that: The axially immovable component (20) is configured as a supporting gasket which is indirectly or directly connected to the top plate and is immovable in the axial direction.

6. The dual clutch according to claim 1 or 2, characterized in that: The return spring is designed such that it is compressed in the axial direction when the pressure plate is moved towards the top plate to build up pressure.

7. The dual clutch according to claim 1 or 2, characterized in that: The first friction clutch (12) and / or the second friction clutch (14) are designed as multi-disk clutches.

8. The dual clutch according to claim 5, characterized in that: The supporting disk is designed as a clutch cover.

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