WO2018077328A1

WO2018077328A1 - Actuator for actuating a clutch, and torque transmission train

Info

Publication number: WO2018077328A1
Application number: PCT/DE2017/100784
Authority: WO
Inventors: Marko Heyne; Viktor Franz; Felix Bunout
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2016-10-27
Filing date: 2017-09-14
Publication date: 2018-05-03
Also published as: CN109844342B; DE102016221159A1; DE112017005425A5; CN109844342A

Abstract

The invention relates to an actuator (1) for actuating a clutch, comprising a drive element (10) which is displaceable in translational fashion, in particular a spindle of a spindle drive, and comprising a piston (110) of a piston-cylinder unit (100), wherein the drive element (10) is mechanically coupled to the piston (110), and the actuator has a radial projection (21) on that end (12) of the drive element (10) which faces toward the piston (110). The actuator furthermore comprises a shell unit (40) which is assembled from multiple individual shells (41, 42) and which is connected to the piston (110) and which encloses the radial projection (21) axially at least in sections and radially at least in sections. The invention also relates to a torque transmission train. With the actuator proposed here, a connection of a hydraulic piston to a linear drive is made possible which is expedient in terms of stresses and which is simple in terms of construction and manufacturing and which at the same time realizes radial play compensation.

Description

Actuator for actuating a clutch and torque transmission train

The invention relates to an actuator for actuating a clutch, in particular a friction clutch of a motor vehicle, as well as a

Torque transmission train of a motor vehicle.

Friction clutches are well known for transmitting torque from a prime mover to a drivetrain, such as one

Powertrain of a motor vehicle. Such friction clutches are often present as non-engaged clutches. That means she's having one

Release system must be actuated to be opened, thus interrupting the torque transmission path.

For this purpose, so-called Zentralausrücker are increasingly used.

Known central disengers used in disengagement systems are, for example, electrical central disengagers or hydraulically functioning central disengagers.

The latter have a piston which can be displaced by a fluid pressure and thus actuate a lever of a clutch.

From WO 2015/1 17 612 A2, an actuator with planetary roller screw spindle is known, which rotatably supports the spindle in a spindle drive in a fixed and translationally displaceable manner. The spindle acts on a displaceably mounted piston for attachment of a fluid pressure. At the end of the spindle facing the piston, a pressure piece is rotatably arranged, which serves as an interface to the piston.

Furthermore, actuators are already known which are embodied, for example, as shown in FIG. Such an actuator 1 has between a spindle end, which is designed here as the cylinder 120 facing the end 12 of the drive member 10 formed as a spindle, and the cylinder 120 designed as a sheet metal pot 2 Connecting element 30 on. This connecting element is the piston of the piston-cylinder unit and acts in the axial direction 30 positively on a radial projection 21 at the spindle end, so that on this form-fitting of the translationally displaceable spindle a force in the connecting element 30 and from this to the sheet metal pot 2 designed piston for the purpose of translational

Displacement of the sheet metal pot 2 is aufbringar. The drive member 10 and the spindle is positively and / or non-positively connected via an undercut 4 with the spindle head 20. The connecting element 30 designed by the radial projection 21, designed as a sheet metal pot 2 and serving as a piston, also holds a sealing ring 60 firmly in the axial direction via a positive connection 5. To produce the positive connection between the radial projection 21 and the designed as a sheet metal pot 2

Connecting element 30, however, is a forming process or a bending of a designed as a tab 3 region of the designed as a sheet metal pot 2

Connecting element 30 during assembly of the actuator necessary.

On this basis, the present invention seeks to provide an actuator that combines a simple and inexpensive installation with optimum functionality and a long service life. The features of the claims may be combined in any technically meaningful manner, for which purpose the explanations of the following description as well as features of the figures may be consulted which comprise additional embodiments of the invention. The terms radial, axial and circumferential direction in the context of the present invention always refer to the axis of rotation of the friction coupling to be connected to the actuator, or to the longitudinal axis of the drive member.

The invention relates to an actuator for actuating a clutch, in particular a friction clutch of a motor vehicle. The actuator comprises a translationally displaceable drive member, in particular a spindle of a spindle drive, and a piston of a piston-cylinder unit, wherein the drive member with the piston is mechanically coupled and the actuator has at the end facing the piston of the drive member has a radial projection.

It is envisaged that the actuator one of several individual shells

composite and connected to the piston shell unit, which surrounds the radial projection at least partially axially and at least partially radially.

The actuator according to the invention is thus a so-called MCA (modular clutch actuator) for actuating a clutch, namely preferably indirectly via a suitable transmission unit, such. a Zentralausrücker.

The spindle drive used is preferably a Planetenwälzgetriebe for

Realization of a linear propulsion with high efficiency.

As a result, in a simple, reliable and efficient manner, a translational displacement of the drive member or the spindle and the coupled thereto

Piston in the axial direction possible. This axial displacement of the piston of the piston-cylinder unit is transmitted hydraulically or pneumatically to another piston. The piston-cylinder unit is also referred to as master cylinder or AMC (Actuator Master Cylinder).

The radial projection is preferably formed by the serving as a drive member spindle itself, or fixed to the spindle end. The radial

Projection extends radially outward than the maximum radial

Extension of the drive member at its end facing the piston.

The axial enclosure of the radial projection by means of the shell unit is such that the shell unit at the radially outer edge of the radial projection encloses at least a segment of the circumference of the radial projection, so that Although an axial displacement of the shell unit with respect to the radial projection is preferably possible with a certain play, but is generally blocked. An individual shell at least partially surrounds the edge of a segment of a radial projection designed as a cylinder. In an advantageous

Embodiment is designed such a single shell as a radial outer side of a hollow Tom. In a preferred embodiment, the shell unit is composed of two identical individual shells. This embodiment of the tray unit allows a simple and inexpensive installation. So it is now no longer necessary to perform a bending operation to produce a positive connection compared to the conventional, designed as a sheet metal fasteners elements.

The mechanical coupling of the piston with the drive member thus takes place via the radial projection and the shell unit. The radial projection is preferably fixedly arranged on the drive member, and the shell unit acts positively and / or non-positively on the piston.

In a preferred embodiment, the tray unit serves as a

Connecting element for connecting the radial projection to the piston, wherein the shell unit has an inner space for receiving the radial projection whose maximum radial extent is greater than the maximum radial extent of the radial projection located in the interior, so that the shell unit and the radial projection in With respect to each other have a radial clearance. Preferably, the radial projection is rotationally symmetrical, so that according to the invention, the diameter of the interior is greater than that

Diameter of the radial projection.

The maximum radial extent of the formed by the shell unit

Interior is in a rotationally symmetrical interior thus the diameter of the interior. The inventive design of the actuator is an optionally occurring lateral offset and in certain areas also one

Angular deviation of the longitudinal axis of the drive member, which also corresponds to the translational movement direction, harmless to the longitudinal axis of the cylinder associated with the piston. Thus, a uniform introduction of force into the pistons is possible, so that there is no stress state that places heavy stress on the components and, as a result, wear over the life of the actuator is reduced.

Preferably, the drive member is a rotationally fixed and translationally displaceable spindle of a spindle drive, in particular a

Planetenwälzgetriebes. The spindle is rotatably supported so that it performs an axial stroke upon rotation of an engaging in the thread of the spindle spindle nut. In an advantageous embodiment of the actuator is provided that the radial projection and the interior are designed substantially cylindrical. It may be that certain deviations from the cylindrical shape exist, such as rounded areas between the lateral surface and the top surfaces. The maximum radial extent of the inner space REi should be in the following ratio to the maximum radial extent of the radial projection REa: REi = 1, 03 to 1, 2 REa, in particular REi = 1, 05REa. As mentioned, the interior and the radial projection are preferably rotationally symmetrical, so that the said ratios are to be applied to the diameters of the interior and the radial projection.

The radial projection may be formed by a spindle head which is mechanically at one end of a spindle forming the drive member

connected.

For the purpose of forming a captive securing device, it is provided in one embodiment that the spindle has an end region facing the piston at its circumference having circumferential groove, wherein the spindle head has at least one molding element which engages radially in the groove.

This structural design prevents axial relative movement between the spindle head and spindle end. The molding element on the spindle head can be a peripheral bead or flanging, which engages in the groove or an exemption in the spindle, or even a single projection or a plurality of projections which engages radially in the groove and which engage radially in the groove. It is a further advantageous embodiment of the actuator, that the shell unit and the piston are mechanically connected to each other at least along the axial direction positively, wherein the positive connection is configured with an axial play. This means that a suitably trained

Form element of the shell unit for the realization of the positive connection and a correspondingly shaped mold element of the piston for the realization of the positive connection are dimensioned such that they are axially movable with respect to each other over a certain distance. The pressure prevailing in the cylinder of the piston-cylinder unit acts on the piston. In an advantageous embodiment of the actuator is provided that a central region of the piston, the pressure force on a centrally disposed portion of the drive member and the radial

Cantilever transmits. In the radially outer region of the cylinder, the pressure force is transmitted to a seal arranged there, which in turn transmits the pressure force to the shell unit. Due to the axial play between the shell unit and the piston, the force introduction regions shell unit and the central region of the radial projection on the drive member are thus decoupled from one another. As a result, any dimensional tolerances that may occur on the piston, on the radial projection and / or on the shell unit do not have a negative effect here. The piston is much less stressed by this division, because bending moments at the transition to the sealing base or the piston crown can no longer occur.

For stable formation of the shell unit, the actuator may comprise a reinforcing element which relates the individual shells of the shell unit in their positions fixed to one another positively and / or positively. The reinforcing element is preferably designed for this purpose as a ring, extending from the radially outer side tabs or clips that engage in correspondingly shaped form elements on the half-shells, so that the half shells form a ring-shaped shell unit as a whole.

The material of the reinforcing element is preferably one which exposes the sealing surface of the inside of the piston-cylinder unit with a friction movement thereon to a lower abrasive wear. It is preferably provided that the reinforcing element at least on the inside of the

Cylinder of the piston-cylinder unit facing side of polyamide, in particular a non-fibrous polyamide, such as a non-glass fiber-filled polymer is executed. A suitable for the purpose of reducing wear material of the tread of the cylinder may be, for example, a thermoplastic material with glass fiber filling.

In a further advantageous embodiment of the actuator is provided that this has a sealing ring as a seal, which is at least positively held by the piston, wherein the piston forms at least one radial projection, the

Applying force to the sealing ring in the axial direction is used. The radial projection may be formed as a radially encircling ring or shoulder or collar. The diameter ratios of piston and sealing ring can also be designed such that in addition to the positive connection between the piston and sealing ring of the sealing ring is fixed by the piston frictionally. Thus, the piston forms a collar as

Leakage protection of the seal.

Thus, an actuator for a clutch of a motor vehicle is provided in which using a drive via a transmission, in particular a Planetenwälzgetriebe, an axially displaceably mounted in a housing piston is displaced so fluidically to relocate another piston, which in turn like For example, in a known Zentralausrücker, a lever spring of the friction clutch actuated. Another aspect of the present invention is a

Torque transmission train, comprising a drive unit with a

Output shaft, a drive train and a friction clutch and a

Actuator according to the invention for actuating the friction clutch, wherein the output shaft for torque transmission by means of the friction clutch with the drive train is detachably connectable. Under the operation of the friction clutch here is the introduction of at least one force in the friction clutch for the purpose of opening the friction clutch in a normally-engaged clutch, and for the purpose of closing the friction clutch in a normally-disengaged clutch to understand.

The torque transmission line is configured to be one of a

Drive unit, for example an energy conversion machine, preferably an internal combustion engine or an electric drive machine,

provided transmitted and output via its output shaft torque for at least one consumer switched on and off. A consumer is, for example, a drive wheel of a motor vehicle or an electric generator for providing electrical energy. Conversely, a recording of an inertial energy introduced by, for example, a drive wheel can also be implemented. The drive wheel then forms the drive unit, wherein its inertial energy by means of the friction clutch to an electric generator for recuperation, ie for the electrical storage of the braking energy, in a suitably equipped drive train is transferable. The above-described invention will be explained in detail in the background of the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is not limited by the purely schematic drawings in any way, it being noted that the embodiments shown in the drawings are not limited to the extent shown. It is shown in 1 shows a conventional actuator for clutch actuation in sectional view,

Fig. 2: an inventive actuator in an exploded view

3 shows a detail of an actuator according to the invention,

Fig. 4: an inventive actuator in sectional view.

The conventional actuator for clutch actuation shown in FIG. 1 has already been referred to in the introduction to the description for explaining the prior art. FIGS. 2 and 3 show the invention-relevant area of the invention

Inventive actuator. FIG. 2 shows the individual parts of the actuator in FIG

Exploded view. It can be seen that the drive member 10 is configured as a spindle which cooperates with a spindle drive 1 1 only partially shown here. The drive member 10 and the spindle is in the embodiment shown here translationally displaceable and rotatably mounted so that it performs a linear stroke upon rotation of a spindle nut on the spindle thread. This stroke acts on the piston 1 shown 10. At the piston 1 10 facing the end 12 of the drive member 10, a so-called spindle head 20 is arranged. This spindle head 20 forms a clearly visible radial projection 21, which extends radially further outward than the drive member 10 itself. This radial projection 21 is configured to a first

Single shell 41 and a second single shell 42, which form a shell unit in the assembled state, to be embraced. To fix the two

Individual shells 41, 42 for forming the shell unit is coaxial with it

Reinforcing element 50 is provided, which the individual shells 41, 42 positively and / or non-positively arranged by engagement from the periphery and axially

extending clips 52 fixed together.

Also coaxial with the piston 1 10 is arranged to receive the

Sealing ring 60 is used. FIG. 3 shows the invention-relevant section in the assembled state in the area of the actuator. Here it is evident that in the here shown

Embodiment of the spindle head 20 on the piston 1 10 facing the end 12 of the drive member 10 is seated. The drive element 10, which is equipped as a spindle, has a groove 13 on its circumference into which, in the embodiment shown here, a shaped element 34 formed on the inside of the spindle head engages by forming a bead 23. As a result, an axial displacement between the spindle head 20 and drive member 10 is prevented. It is also apparent from Figure 3, that the two individual shells a

Form shell unit 40, which here represents the connecting element 30 between the spindle head 20 and the piston 1 10. The radially outer edge 22 of the radial projection 21 is surrounded by the shell unit 40 radially and in the edge region also axially. The shell unit 40 thus forms an interior 31, which has a maximum radial extent 32. This maximum radial extent 32 of the inner space 31 is much greater than the maximum radial extent 25 of the radial projection 21, thereby creating a radial clearance 70 between

Shell unit 40 and the spindle head 20 and consequently also to the

Drive member 10 is made. This radial play 70 allows for a slight lateral displacement of the longitudinal axis of the drive member 10 with respect to the longitudinal axis of the piston-cylinder unit 100.

In the axial direction between the shell unit 40 and a radial projection 1 1 on the piston 1 10, a sealing ring 60 is arranged, which is supported with its sealing base 61 on the reinforcing element 50. In the embodiment illustrated here, the shell unit 40 or its individual shells are received in a groove 1 12 in the piston 1 10. This groove 1 12 and the engaging portions of the shells of the shell unit 40 are dimensioned such that an axial play 80 exists. This axial clearance 80 causes a decoupling of the acted upon by the compressive forces 130 parts of the actuator. As shown, the piston 10 acted upon by pressure force 130 acts with its central region directly on the spindle head 20 and thus on the drive member 10. In the radially outer region of the cylinder 120 acts the pressure force 130 on the sealing ring 60 and from there via the reinforcing element 50 on the shell unit 40. Due to the axial play 80 between the

Shell unit and the piston, if necessary, existing tolerances or angular deviations do not significantly increase the wear.

It can be seen that the reinforcing element 50 bears with its radially outer race 51 directly against the sealing surface 122 of the cylinder 120. By a suitable material pairing wear can be prevented here. By actuating the spindle drive can thus be the drive member 10th

move translationally, so that this is entrained by the entrainment on the mold member 24 on the spindle head 20 and consequently also connected via the shell unit 40 to the spindle head 20 piston 1 10 and the sealing ring 60 are taken and moved in the cylinder interior 123. The translational movement can take place so far that the illustrated Schnüffelnuten 121 are covered by the interior of the cylinder 120 and

Consequently, a tracking of fluid in the cylinder 120 can take place. In a movement of the piston 1 10 in the opposite direction, this can move by generating a fluid volume flow another, not shown here piston, which exerts a force for actuating a coupling element, such as a lever spring exerts.

Figure 4 shows a modular clutch actuator 200, in which case clearly the spindle drive 1 1 can be seen, which realizes the translational displacement of the designed as a spindle drive member 10. This leads to a

translational displacement of the piston 1 10 in the cylinder 120 of the piston-cylinder unit 100th

With the actuator proposed here is thus a tension-favorable and constructive and manufacturing technology simple connection of a hydraulic piston to a linear drive with simultaneous radial clearance compensation possible. LIST OF REFERENCES

1 actuator

2 tin pot

3 bent tab

4 undercut

5 form fit

10 drive member

1 1 spindle drive

12 facing the piston end

13 groove

20 spindle head

21 radial projection

22 radially outer edge

23 bead

24 shaped element

25 maximum radial extent REa

30 connecting element

31 interior

32 maximum radial extent REi

40 shell unit

41 first single bowl

42 second single shell

50 reinforcing element

51 career

52 clip

60 sealing ring

61 sealing floor

70 radial clearance

80 axial play

100 piston-cylinder unit 110 piston

111 radial projection

112 groove

120 cylinders

121 sniffing groove

122 sealing surface

123 cylinder interior

130 pressure force

200 Modular clutch actuator

Claims

claims

Actuator (1) for actuating a clutch, in particular a friction clutch of a motor vehicle, comprising a translationally displaceable drive member (10), in particular a spindle of a spindle drive, and a piston (1 10) of a piston-cylinder unit (100), wherein the drive member (10) is mechanically coupled to the piston (1 10) and the actuator on the said piston (1 10) facing the end (12) of the drive member (10) has a radial projection (21), characterized in that the actuator

a shell unit (40) composed of a plurality of individual shells (41, 42) and connected to the piston (110), which radially surrounds the radial projection (21) at least in sections and at least in sections.

Actuator according to claim 1, characterized in that the shell unit

(4) as a connecting element (30) for connecting the radial projection (21) with the piston (1 10), wherein the shell unit (40) has an inner space (31) for receiving the radial projection (21) whose maximum radial Extension (32) is greater than the maximum radial extent (25) of the in the interior (31) located radial projection (21), so that the shell unit (40) and the radial projection (21) with respect to each other a radial clearance (70 ) exhibit.

Actuator according to one of claims 1 and 2, characterized in that the drive member (10) is a rotationally fixed and translationally movable spindle of a spindle drive (1 1), in particular a Planetenwälzgetriebes.

Actuator according to one of claims 2 and 3, characterized in that the maximum radial extent of the inner space (32) REi to the maximum radial extent of the radial projection (25) REa is in the following ratio: REi = 1, 03 to 1, 2 REa.

5. Actuator according to one of claims 3 and 4, characterized in that the radial projection (21) by a spindle head (20) is formed, which is mechanically connected to one end of the drive member (10) forming the spindle.

6. Actuator according to claim 5, characterized in that the spindle has at its end facing the piston end region (12) on the circumference circumferential groove (13), wherein the spindle head (20) has at least one form element (24) which radially into the Groove (13) engages.

7. Actuator according to one of the preceding claims, characterized in that the shell unit (40) and the piston (1 10) are mechanically connected to each other at least along the axial direction positively, wherein the positive connection with an axial clearance (80) is configured.

8. Actuator according to one of the preceding claims, characterized in that the actuator comprises a reinforcing element (50) which fixed the individual shells (41, 42) of the shell unit (40) in their positions with respect to one another force and / or positive fit.

9. Actuator according to one of the preceding claims, characterized in that the actuator has a sealing ring (60), at least form-fitting manner from the piston

(1 10) is held, wherein the piston (1 10) at least one radial projection

(1 1 1) forms, which serves to apply force to the sealing ring (60) in the axial direction.

10. torque transmission train, comprising a drive unit with a

Output shaft, a drive train and a friction clutch and an actuator (1) according to one of claims 1 to 9 for actuating the friction clutch, wherein the output shaft for torque transmission by means of the friction clutch with the drive train is detachably connectable.