WO2021219156A1

WO2021219156A1 - Central release arrangement

Info

Publication number: WO2021219156A1
Application number: PCT/DE2021/100303
Authority: WO
Inventors: Kirill PROKHOROV
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2020-04-27
Filing date: 2021-03-26
Publication date: 2021-11-04
Also published as: DE102020111380B3; CN115298453A

Abstract

The invention relates to a central release arrangement (1), in particular for a hydraulic release system (2) of a clutch system (3) of a motor vehicle (4), comprising a central release housing (5) with an annular central release piston chamber (6), in which a central release piston (8) is received axially movably by a hydraulic liquid (7) that can be supplied to the central release piston chamber (8), wherein the central release piston (8) has at least one central release piston seal (9) which seals the central release piston (8) with respect to the central release piston chamber (6), the central release piston (8) comprising at least one annular guide groove (10) extending in the axial direction, which engages into a corresponding piston guide ring (11) that extends in the axial direction and is arranged on the central release housing (5), so that the central release piston (8) is guided in an axially displaceable manner on the piston guide ring (11).

Description

Central slave cylinder arrangement

The invention relates to a central release system, in particular for a hydraulic release system of a clutch system of a motor vehicle, comprising a central release housing with an annular central release piston chamber in which a central release piston is axially movably received by a hydraulic fluid that can be supplied to the central release piston, the central release piston having at least one central release piston seal ral release piston seals against the central release piston space.

Central release arrangements, in particular for a hydraulic release system egg nes clutch system of a motor vehicle, are well known from the prior art.

There is a continuing need to optimize central release arrangements with regard to their service life, functional reliability and production costs. The task of the invention is therefore to provide a correspondingly improved Zentralaus Rückeranordnung

This object is achieved by a central release arrangement, in particular for a hydraulic release system of a clutch system of a motor vehicle, comprising a central release housing with an annular central release piston space in which a central release piston is axially movably received through a hydraulic fluid that can be supplied to the central release piston, the central release piston having at least one central release piston which seals the central release piston against the central release piston space, the central release piston having at least one annular guide groove extending in the axial direction, which engages in a corresponding piston guide ring which extends in the axial direction and is arranged on the central release housing, so that the central release piston engages on the Piston guide ring is guided axially displaceably. A significant advantage of the central release assembly according to the invention is that the central release piston is internally guided, ie is axially movably mounted on a corresponding piston guide ring of the central release housing via a guide groove formed in the central release piston. In this way, on the one hand, greater stability against wobbling and tilting of the central return piston can be achieved during operation. On the other hand, an internally guided central release piston also enables guidance in the wet area of the central release arrangement, which significantly reduces the wear and tear on the components that move against one another and improves the operational reliability of the central release arrangement accordingly. Furthermore, this means that reinforcement between the moving components, which has hitherto been frequently used, can be dispensed with.

In particular, due to the internally guided central release piston, the inner outer surfaces of the central release piston space are only mechanically stressed by the seals, so that practically no mechanical wear is to be expected on these sealing surfaces and consequently a high and reliable sealing effect can be achieved.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are named in the set of claims and particularly preferred embodiments of the subject matter of the invention are described below.

Fully hydraulic clutch systems of motor vehicles can be equipped with a central releaser, which is often referred to as a Concentric Slave Cylinder (CSC). This can in particular consist of an annular hydraulic central release cylinder with an integrated release bearing, which is preferably arranged in the clutch housing between the transmission and the clutch in the middle of the transmission input shaft, whereby the lever in the transmission bell housing, as used in arrangements with a conventional slave cylinder, ent can fall. In vehicles with manually operated dry clutches, the pedal force generated by the driver must be amplified by a mechanism and transmitted to the clutch. Hydraulic clutch actuation is used in modern foot-operated clutches. In the fully hydraulic system, the functions of the gear-side release mechanism are taken over by a central slave cylinder (CSC - Concentric Slave Cylinder). This is located directly in the bell housing between the gearbox and the clutch.

A hydraulic release system usually has a master cylinder that transmits the pressure generated on the master cylinder to the slave cylinder via a hydraulic pressure line. The slave cylinder transmits by means of an axially displaceable piston and with the interposition of a clutch release bearing the hydraulic pressure to a lever system, which can be formed, for example, by a plate spring. The diaphragm spring acts on a clutch pressure plate connected to a clutch housing in a rotationally fixed and axially displaceable manner and is braced against a pressure plate firmly connected to the clutch housing. A clutch disc with a clutch lining is arranged between the pressure plate and the clutch pressure plate, which, depending on the tension between the pressure plate and the clutch pressure plate, form a frictional connection and close the friction clutch or open when the frictional connection is canceled.

A clutch system for motor vehicles has the function of coupling or decoupling the driving motor side in a drive train of a vehicle in a switchable manner from the transmission side and thus enabling a gear change of the transmission while driving and thereby operating the driving motor in a preferred speed / torque range to be able to.

A basic distinction is made between manually operated clutch systems and automatic clutch systems. In a manually operated clutch system, the clutching and disengaging process is triggered and controlled manually by the driver, for example by actuating a clutch pedal in a muscular manner.

In automatic clutch systems, this control and actuation is taken over by an electronic control and actuators, so that the Driver is no longer required to change gears while driving. As a result, automatic clutch systems usually do not have a clutch pedal either.

In order to allow the driver a certain manual intervention in gear selection even with automatic clutch systems, steering wheel buttons, for example, are also known for manual gear selection in automatic clutch systems, but the clutch and shift processes are also controlled automatically by the clutch system.

As motor vehicles in the sense of this application are land vehicles that are moved by machine power without being tied to railroad tracks. A motor vehicle can for example be selected from the group of passenger cars (cars), trucks (trucks), small motorcycles, light vehicles, motorcycles, buses and coaches (KOM) or tractors.

The central release housing can be designed in one piece or in several pieces. The central release housing can preferably be formed from a plastic, a metallic material and / or ceramic material.

The central release piston space formed in the central release housing serves to accommodate and guide the central release piston, which is mounted in a linearly movable manner in the central release housing.

In a hydraulic release system of a motor vehicle, the hydraulic fluid has the function of transmitting energy in the form of pressure with as little loss as possible, for example within a vehicle's clutch system. In addition to this main task, the hydraulic fluid can also provide lubrication and corrosion protection for the moving parts and the metal surfaces of the hydraulic release system. In addition, it can in particular also dissipate impurities (for example from abrasion), water and air as well as waste heat.

The function of the central release piston is to convert a hydraulic pressure application into a linear displacement of the central release piston has the effect that the clutch system can be transferred from an engaged operating state to a disengaged operating state. The central release piston can have an annular central release piston or several central release pistons (multi-piston release mechanism).

The central release piston seal seals the linearly movable central release piston from the central release housing that accommodates the central release piston. The central release piston seal can in particular be designed as a sealing ring. The central release piston seal can in particular be positively connected to the central release piston. Particularly preferred is a positive connection between the central release piston and the central release piston seal designed as a snap connection.

According to a preferred embodiment of the invention, it can be advantageous that the central release piston is formed from a plastic, in particular a fiber-reinforced plastic. As a result, the central release piston can be manufactured in a cost-effective manner, with more complex component geometries also being able to be realized by injection molding processes. The strength of the Zentralausrückerkol ben can be improved through the use of fiber-reinforced, in particular glas-fiber reinforced plastics.

It can furthermore be advantageous for the central release housing and / or the piston guide ring to be formed from a plastic, in particular a fiber-reinforced plastic. In this way, the central release housing and / or the piston guide ring can be manufactured in a cost-effective manner, with more complex component geometries also being able to be realized by injection molding processes. The strength of the central release housing and / or the piston guide ring can be improved by using fiber-reinforced, in particular glass-fiber-reinforced plastics.

In a further development of the invention, it can also be preferred that the central release housing and the piston guide ring are monolithic. It is particularly preferred that the piston guide ring and the central Release housing are injection molded from a plastic, which means that manufacturing costs can be further optimized. In principle, it is also conceivable that bi-injection molding processes are used, so that, for example, the piston guide ring is made of a different plastic than the central release housing, but both components are molded monolithically in injection molding.

Furthermore, it can be advantageous that the piston guide ring protrudes into the central return piston space, so that the piston guide ring is at least partially surrounded by hydraulic fluid. This basically makes it possible to provide lubrication of the central release piston with respect to the piston guide ring. This configuration of the piston guide ring also makes it possible to achieve a particularly compact axial design.

According to a further advantageous embodiment of the invention, it can be preferred that the guide groove of the central release piston and the piston guide ring are configured in such a way that, when installed, they form a lubrication ring gap between their contact surfaces that can be penetrated by hydraulic fluid and through which the central release piston is lubricated and mounted on the piston guide ring. In this way, lubrication can be implemented along the opposing surfaces of the guide groove and piston guide ring. It is particularly preferable that the lubrication ring gap is designed in such a way that lubrication is implemented completely along the opposing surfaces of the guide groove and piston guide ring. Furthermore, the hydraulic fluid can remove wear particles from the lubrication ring gap so that they do not cause any undesired surface defects at the contact points between the guide groove and the piston guide ring.

According to a preferred embodiment of the invention, it can be advantageous that the central release piston, the guide groove, the piston guide ring and the central release piston chamber are configured in such a way that contact of the piston guide ring with the central release piston chamber is prevented in the event of an axial displacement of the central release piston on the piston guide ring. The "inner" guidance of the central release piston on the piston guide ring prevents the central release piston from wobbling or tilting when the central release piston is in operation. be changed. One of the reasons for this is that the central release piston is guided over the guide groove on the piston guide ring practically over the entire surface and not just at certain points. This also results in a comparatively axially elongated guide, which provides greater security against wobbling and / or tilting movements of the central release piston on the piston guide ring.

It can furthermore be advantageous that the guide groove of the central release piston has an axial depth which corresponds to between 50-95%, preferably between 65-90%, particularly preferably between 75-90% of the axial length of the central release piston. This enables a particularly high level of security against unwanted wobbling and / or tilting movements of the central release piston.

In a further development of the invention, it can furthermore be preferred that the piston guide ring and the guide groove of the central release piston define an end stop of the central release piston that acts in an axial direction, whereby a particularly compact axial design and simple construction of the central release can be achieved.

The invention is explained in more detail below with reference to figures without restricting the general idea of the invention. The figures are merely of a schematic nature and are used exclusively for understanding the invention. The same elements are provided with the same reference symbols. The different features of the various exemplary embodiments can also be freely combined with one another within what is technically feasible.

Show it:

1 shows a central release arrangement according to the invention in a schematic cross-sectional view,

2 shows a central release arrangement according to the invention in a schematic cross-sectional view, and FIG 3 shows a motor vehicle with a central release arrangement according to the invention in a schematic block diagram.

Figure 1 shows an embodiment of a central release assembly 1 for a hydraulic release system 2 of a clutch system 3 of a motor vehicle 4, as shown by way of example in FIG.

The central release arrangement 1 comprises a central release housing 5 with an annular central release piston space 6 in which a central release piston 8 is axially movably received by a hydraulic fluid 7 which can be supplied to the central release piston space 6. The central release piston 8 has two central release piston seals 9 which seal the central release piston 8 from the central release piston space 6.

The central release piston 8 is characterized by an annular guide groove 10 extending in axia ler direction, which engages in a corresponding piston guide ring 11 extending in the axial direction and arranged on the central release housing 5, so that the central release piston 8 is guided axially on the piston guide ring 11 . The guide groove 10 is annular in the embodiment shown in FIG.

In principle, although not shown in FIG. 1, it is also conceivable that the guide groove 10 has ring sections with different axial groove depths which engage in a correspondingly designed piston guide ring with corresponding piston guide ring sections. As a result, the friction between the components and the storage can be further optimized or adapted.

If the hydraulic pressure is increased by means of the hydraulic fluid 7 in the central release piston space 6, which is indicated by the arrow in FIG. 1, the central release piston 8 is displaced linearly to the left from its end position shown on the piston guide ring 11, which is indicated by the arrow is indicated. In the exemplary embodiment shown, the central release piston 8 is made of a plastic, in particular a fiber-reinforced plastic. The Zentralaus Rückergehäuse 5 and the piston guide ring 11 are monolithically made of a plastic, in particular a fiber-reinforced plastic.

The piston guide ring 11 protrudes into the central release piston chamber 6 in such a way that the piston guide ring 11 is at least partially exposed to hydraulic fluid 7. The guide groove 10 of the central release piston 8 and the piston guide ring 11 are also configured in such a way that, when installed, they form a lubrication ring gap 12 between their contact surfaces that can be penetrated by hydraulic fluid 7 and through which the central release piston 8 is lubricated and mounted on the piston guide ring 11.

1 that the central release piston 8, the guide groove 10, the piston guide ring 11 and the central release piston space 6 are configured in such a way that when the central release piston 8 is axially displaced on the piston guide ring 11, the piston guide ring 11 contacts the central release piston space 6 is prevented. This is essentially caused by the fact that the central release piston 8 is guided over the entire surface with the inner circumferential surface of the guide groove 10 to the piston guide ring 10, whereby wobbling or tilting of the central release piston 8 is largely prevented.

This is also explained again with reference to FIG. It is shown here that the guide groove 10 of the central release piston 8 has an axial depth 13 which corresponds to between 50-95%, preferably between 65-90%, particularly preferably between 75-90% of the axial length 14 of the central release piston 8, whereby a sufficiently secure guide on the piston guide ring 10 can be provided. In one of its two end positions, which is shown in FIG. 2, the piston guide ring 10 plunges completely into the guide groove 10 of the central release piston 8. The piston guide ring 11 and the guide groove 10 of the central release piston 8 thus define an end stop of the central release piston 8 that acts in an axial direction. It can also be seen from FIG. 2 that the radially outer leg of the guide groove 10, which is U-shaped in cross section, is axially shorter than the radially inner leg. As a result, in particular weight and material savings can be realized without neglecting stable guidance of the central release piston 8.

FIG. 1 also shows that the central release arrangement 1 with its hydraulic high-pressure pressure line can be connected to a hydraulic control and actuator unit 15, which conveys hydraulic fluid 7 into the central release piston space 6 for actuating the central release piston 8. In principle, leakage flows of hydraulic fluid 7 can occur at the contact surfaces between the seals 9 and the inner circumferential surface of the central release piston chamber 6, as is indicated schematically in FIG. This leakage flow of hydraulic fluid 7 is collected and stored in the illustrated embodiment in a sump, not shown in detail. The hydraulic control and actuator unit 15 conveys hydraulic fluid 7 from the sump, which is on the low-pressure side of the hydraulic release system, and applies a pressurized hydraulic fluid 7 to the Zentralausrückerkol 6 to compensate the Zentralaus Rückergehäuse 5.

The directions used in this application, axial, radial, tangential and / or circumferential, relate to an imaginary axis of rotation of the component in question or described.

The invention is not limited to the embodiments shown in the figures. The above description is therefore not to be regarded as restrictive, but rather as explanatory. The following claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Insofar as the patent claims and the above description define “first” and “second” features, this designation serves to distinguish between two features of the same type without defining an order of precedence. Bezuqszeichenliste Central release system hydraulic release system clutch system motor vehicle central release housing central release piston space hydraulic fluid central release piston central release piston seal guide groove piston guide ring lubrication ring gap axial depth axial length hydraulic control and actuator unit

Claims

1 . Central release arrangement (1), in particular for a hydraulic release system (2) of a clutch system (3) of a motor vehicle (4), comprising a central release housing (5) with an annular central release piston space (6) in the hydraulic fluid which can be fed to the central release piston space (6). 7) a central release piston (8) is accommodated in an axially movable manner, the central release piston (8) having at least one central release piston seal (9) which seals the central release piston (8) against the central release piston space (6), characterized in that the central release piston (8) has at least one ring-shaped guide groove (10) extending in the axial direction, which engages in a corresponding piston guide ring (11) which extends in the axial direction and is arranged on the central release housing (5), so that the central release piston (8) on the piston guide ring (11) is guided axially displaceably.

2. Central release assembly (1), according to claim 1, characterized in that the central release piston (8) is formed from a plastic, in particular a fiber reinforced plastic.

3. Central clutch release arrangement (1), according to one of the preceding claims, characterized in that the central clutch release housing (5) and / or the piston guide ring (11) made of a plastic, in particular a fiber-reinforced plastic, forms GE.

4. Central release arrangement (1), according to one of the preceding claims, characterized in that the central release housing (5) and the piston guide ring (11) are monolithic.

5. Central release assembly (1), according to one of the preceding claims, characterized in that the piston guide ring (11) protrudes into the central release piston space (6) so that the piston guide ring (11) is at least partially surrounded by hydraulic fluid (7).

6. Central release assembly (1), according to one of the preceding claims, characterized in that the guide groove (10) of the central release piston (8) and the piston guide ring (11) are configured so that in the installed state they have a hydraulic fluid (7 ) Form penetrable lubrication ring gap (12) through which the central release piston (8) is lubricated and mounted on the piston guide ring (11).

7. Central release assembly (1), according to one of the preceding claims, characterized in that the central release piston (8), the guide groove (10), the piston guide ring (11) and the central release piston space (6) are configured so that upon axial displacement of the central release piston (8) on the piston guide ring (11) contact of the piston guide ring (11) with the central release piston space (6) is prevented.

8. Central release arrangement (1), according to one of the preceding claims, characterized in that the guide groove (10) of the central release piston (8) has an axial depth (13) which is between 50-95%, preferably between 65-90%, especially preferably between 75-90% of the axial length (14) of the central release piston (8).

9. Central release assembly (1) according to one of the preceding claims, characterized in that the piston guide ring (11) and the guide groove (10) of the central release piston (8) define an end stop of the central release piston (8) acting in an axial direction.