Actuating device for a multi-plate clutch and drive arrangement for a motor vehicle

Abstract

Actuating device for a multi-plate clutch (30), comprising - an axially displaceable release ring (41) connected to a release element (33) acting axially on a disk pack of the multi-disk clutch (30) and - an axially fixed support ring (43) coaxially coupled to the release ring (41) via a ball ramp, one of which is rotatably mounted and provided with a toothed section (421) extending in the circumferential direction and acts as an adjusting ring (42) of a ball ramp mechanism, wherein the toothed section (421) of the adjusting ring (42) meshes with a spur toothing (511) of an intermediate gear (50), which in turn is connected to a drive pinion (60) via a further tooth engagement in a torque-transmitting manner, and wherein the intermediate gear (50) has two axial sections (51, 52), namely - a spur-toothed, first axial section (51) which meshes with the toothed section (421) of the adjusting ring (42) designed as a spur toothing, and - a ring gear-like second axial section (52) which meshes with the correspondingly designed drive pinion (60), characterized in that the second axial section (52) of the intermediate gear (50) carries a crown toothing (521) which meshes with a corresponding spur toothing (601) of the drive pinion (60), wherein the crown toothing (521) and the spur toothing (601) are helical or curved toothed in a corresponding manner to one another and the drive pinion (60) is designed as a worm.

Description

Field of the invention

[0001] The invention relates to an actuating device for a multi-disk clutch, comprising - an axially displaceable release ring connected to a release element acting axially on a plate pack of the multi-plate clutch and - an axially fixed support ring coaxially coupled to the release ring via a ball ramp, one of which is rotatably mounted and provided with a toothed section extending in the circumferential direction and acts as an adjusting ring of a ball ramp mechanism, wherein the toothed section of the adjusting ring meshes with a spur toothing of an intermediate gear, which in turn is connected to a drive pinion via a further tooth engagement in a torque-transmitting manner and wherein the intermediate gear has two axial sections, namely - a spur-toothed first axial section which meshes with the toothed section of the adjusting ring designed as a spur toothing, and - a ring gear-like second axial section which meshes with the correspondingly designed drive pinion.

[0002] The invention further relates to a drive arrangement for a motor vehicle, comprising a first input shaft connectable to a first drive unit and a coaxially arranged output shaft connectable to an output, which are coupled to one another via a multi-plate clutch actuated by means of an actuating device of the aforementioned type. State of the art

[0003] Such an actuating device and such a drive arrangement are known from DE 103 34 468 A1.

[0004] The state of the art offers a wide variety of applications for the automated control of multi-plate clutches. Particularly in automotive engineering, automatically controllable multi-plate clutches are a typical type of switchable, torque-transmitting coupling between two coaxial shafts, namely from an input shaft to an output shaft. The input shaft is connected in a rotationally fixed manner to the inner or outer plate carrier of the multi-plate clutch, while the output shaft is connected to its outer or inner plate carrier, respectively. The intermittently arranged inner and outer plates are axially displaceable and can be pressed together in a controlled or, advantageously, regulated manner by means of a release element acting axially on them, typically a rotationally decoupled thrust washer. This disengagement of the thrust washer usually occurs against the force of a preload spring, which is often designed as a disc spring.

[0005] The so-called ball ramp mechanism has proven effective for controlling the thrust washer. Two coaxial rings pressed against each other by the preload spring clamp balls between them, which are guided in recesses that extend in the circumferential direction and whose depth monotonically varies, i.e. ramp-shaped. Relative rotation of the two rings therefore leads to a change in the axial distance between the rings, which is dependent on the angle of rotation. One of the rings, referred to here as the support ring, is axially fixed relative to a fixed reference base, so that the other ring, referred to here as the release ring, is axially displaced in the event of relative rotation. The release ring is connected to the above-mentioned release element (in particular it can be identical to it) and thus causes the multi-plate clutch to disengage.The relative rotation of the support and release rings is usually achieved by rotating only one of them relative to the fixed reference base. The rotating ring is referred to here as the adjusting ring. However, it is also possible to design both the support and release rings as adjusting rings.

[0006] From the aforementioned generic publication, a clutch actuation device is known in which the coupling between the adjusting ring and the servomotor is established via an intermediate gear with two spur-toothed axial sections. The radially smaller one meshes with a spur toothing of the adjusting ring; the radially larger one meshes with a spur toothing of an extension of the servomotor shaft. A disadvantage is that, although the orientation of the servomotor axis can be selected within a certain, limited solid angle, the servomotor is arranged essentially axially parallel to the input and output shafts. However, there is typically little installation space available in this direction in automotive construction. A further disadvantage is that the return spring of the clutch arrangement requires continuous current supply to the servomotor unless a completely relaxed clutch position is desired.

[0007] The problem of axial alignment of the actuator is solved in US 2001 / 0047919 A1 in that the support ring, which acts as an adjusting ring, is driven by a worm whose worm gearing meshes with the spur gearing of the support ring, and whose worm axis, aligned tangentially to the support ring, is directly driven by an actuator that is also oriented tangentially to the support ring. The problem of maintaining a predetermined clutch position without continuous current supply to the actuator is solved in that both the support ring and the release ring are rotatably mounted, whereby unwanted rotation of the support ring can be prevented by the self-locking of the worm, and unwanted rotation of the release ring, which has its own external gearing, can be prevented by an electromagnetically operated fixing pin that can be inserted into a tooth gap in the release ring's external gearing.A disadvantage is the lack of a transmission ratio between the actuator and the adjusting or support ring, which requires a very high-torque actuator. Such a motor has a relatively large radial design. However, the limited axial space (relative to the ball ramp arrangement) often prevents appropriate dimensioning of the actuator, which is arranged tangentially in the main plane of the adjusting ring.

[0008] In US 2007 / 002 32 52 A1, the support ring is not only axially but also rotationally fixed. The release ring, on the other hand, is both axially and rotationally movable and therefore acts as an adjusting ring. It is rotationally decoupled from the thrust washer, which acts directly on the disk packs, by a pivot bearing. It carries crown gearing that meshes with a cylindrical spur gear, which acts as an intermediate gear. The spur gearing of the intermediate gear also meshes with a worm gear, whose worm axis is perpendicular to the axis of the intermediate gear and parallel to the input and output shafts. The worm gear is connected to an electric motor actuator, which provides the torque required to disengage the multi-plate clutch in a controlled manner.

[0009] US 2007 / 0180940 A1 discloses a spiral cam clutch with two intermediate gears between the servomotor and the adjusting disc. The first of these is designed as a simple spur gear that meshes with the spur gearing of the adjusting disc. The second has two axial sections, one of which, radially smaller, also meshes with the spur gearing of the first intermediate gear, and the other, radially larger, is designed like a ring gear and is provided with a bevel gear that meshes with a corresponding bevel gear on the motor shaft of the servomotor.

[0010] Hering, Modler: Fundamentals of Engineering. 14. Munich: Carl Hanser Verlag, 2007. - ISBN 978-3-446-22814-6 discloses several gear pairings familiar to the expert. Task

[0011] It is the object of the present invention to ensure greater flexibility in the selection of the orientation of the servo motor and to make it possible to maintain disengaged states of the clutch even with the servo motor de-energized. Description of the invention

[0012] This object is achieved in the context of an actuating device for a multi-plate clutch having the features of the preamble of claim 1 in that that the second axial section of the intermediate gear carries a crown toothing which meshes with a corresponding spur toothing of the drive pinion, wherein the crown toothing and the spur toothing are helical or curved toothed in a corresponding manner to one another and the drive pinion is designed as a worm. In the context of a drive arrangement having the features of the preamble of claim 4, the object is achieved in that the actuating device is designed as an actuating device according to the invention of the aforementioned type.

[0013] The idea of ​​coupling the actuator via an angular drive, which is fundamentally known from the prior art, is also retained within the scope of the present invention. However, differences arise with regard to the specific nature of this angular drive. Thus, the toothing of the adjusting ring is, as previously known, designed as a simple spur toothing that meshes with a corresponding spur toothing of an axially parallel pinion. According to the invention, the pinion is a component of a combination gear that has a spur-toothed axial section (namely, the said pinion) and a ring gear-like, crown-toothed axial section. The actual drive pinion, which bears a corresponding toothing and is designed according to the invention as a worm, then meshes with this second axial section.Due to the selectability of the specific toothing of the ring gear on the one hand and the considerable degrees of freedom in the alignment of a corresponding drive pinion on the other, the design freedom in the design of a drive assembly according to the invention is so great that the servo motor can be positioned at almost any location within the necessary installation space. This freedom in the design of a drive assembly represents a significant value given the notorious shortage of installation space in automotive construction. This freedom is essentially the result of the design of the intermediate gear as a combination gear with two different toothings.Whereas in the prior art the adjusting ring toothing on the one hand and the drive pinion toothing on the other hand engage with the same spur toothing of the intermediate gear, the combination gear, as which the intermediate gear is designed according to the invention, offers two interfaces optimized for the respective tooth engagement.

[0014] Conveniently, the release ring acts as the aforementioned adjusting ring for the ball-ramp mechanism. Since, as explained above, disengagement only requires a relative rotation between the support ring and the release ring, the support ring could also be used as an adjusting ring. However, this would require its additional pivot bearing, which is considered less advantageous, especially from a cost perspective.

[0015] According to the invention, the second axial section of the intermediate gear has a crown gearing that meshes with a corresponding spur gearing of the pinion. Particularly in cases where a vertical alignment of the actuator relative to the input and output shafts is desired, this gearing variant is preferable to a bevel gear stage due to its improved efficiency and reduced wear, as well as the elimination of axial forces.

[0016] The crown gear and the spur gear are helical or spiral-cut, particularly preferably helical. This represents the optimal compromise between efficiency and manufacturability. The drive gear is designed as a worm gear. This is advantageous due to the self-locking nature of a worm gear, as the actuator can remain de-energized in all stationary states, especially when disengaged against the force of the preload spring.

[0017] Advantageously, the axes of the intermediate gear and the drive pinion are skewed relative to each other, i.e., the angular drive exhibits a so-called axial offset. Angular drives with axial offset exhibit better efficiency than those without axial offset, i.e., those with intersecting axes of the ring gear and drive pinion.

[0018] In a further development of a drive arrangement according to the invention, the first input shaft carries a spur-toothed coupling gear which meshes with a coupling pinion arranged on a second input shaft which can be connected to a second drive unit. The first and second input shafts can preferably be arranged axially parallel. The second input shaft allows the coupling of an additional torque from a second drive unit. For example, the torques of an internal combustion engine and an electric machine can be coupled in this way. The electrically coupled torque can have a positive or negative sign, i.e. the electric machine can be operated as a motor or generator.

[0019] Further features and advantages of the invention will become apparent from the following specific description and drawings. Short description of the drawings

[0020] They show: Fig. 1: a sectional view of a drive arrangement suitable for use with an actuating device according to the invention, not shown, Fig. 2: a side view of the drive arrangement of Fig. 1 with actuating device according to the invention, Fig. 3: a partially sectioned view of the drive device of Fig. 2, Fig. 4: a partially sectioned view of the drive arrangement of Fig. 2. Detailed description of preferred embodiments

[0021] The same reference numerals in the figures indicate the same or analogous elements.

[0022] Fig. 1 shows a sectional view of a drive arrangement for a motor vehicle, but without showing the multi-plate clutch actuating device according to the invention. Fig. 1 serves only to illustrate the basic coupling mechanism.

[0023] The arrangement of Fig. 1 comprises a first input shaft 11 and an output shaft 20, which are switchably coupled to one another by means of a multi-plate clutch 30. The first input shaft 11 can be connected to a first drive unit, for example, an internal combustion engine, by means of a spline 111. The output shaft 20 can be connected to further output components, for example, a transmission or a differential, by means of a spline 201. Furthermore, the arrangement of Fig. 1 a second input shaft 12 having a spur-toothed coupling pinion 122 that meshes with a corresponding spur-toothed coupling gear 112 of the first input shaft 11. The second input shaft 12 is connectable to a second drive unit so that its (positive or negative) torque can be added to the torque of the first drive unit and applied to the first input shaft 11.

[0024] The first input shaft 11 is connected in a rotationally fixed manner to the outer disk carrier 31 of the multi-plate clutch 30. Its inner disk carrier 32 is connected in a rotationally fixed manner to the output shaft 20. By means of a release element designed as a thrust bearing 33, the disks of the multi-plate clutch 30 can be pressed together against the preload of a preload spring (not shown), creating a frictionally engaged connection. In this state, the torque applied to the first input shaft 11 (of the first and / or second drive unit) is transmitted to the output shaft 20. In the deactivated state of the multi-plate clutch 30, however, its disks can rotate relative to one another without torque transfer.

[0025] The axial movement of the thrust bearing 33 required to disengage the multi-plate clutch 30 is achieved via a ball ramp mechanism 40. An axially movable release ring 41, which, as explained in more detail below, also acts as an adjusting ring 42, bears against the thrust bearing 33. On the side facing away from the thrust bearing 33, the release ring 41 carries a circumferentially extending ball track 44 in which a set of rolling balls is mounted. The rolling balls are also mounted in ramp-shaped ball guides 45 of an axially and rotationally fixed support ring 43. A relative rotation of the release ring 41 and the support ring 43, which in the embodiment shown is caused by a rotation of the release ring 41 acting as an adjusting ring 42, thus leads to an axial displacement of the release ring 41, which causes an actuation of the multi-plate clutch 30 via the thrust bearing 33 in the manner explained above.

[0026] Fig. 2 shows the arrangement of Fig. 1 in a side view, additionally showing an actuating device according to the invention for generating the above-explained rotational movement of the adjusting ring 42. The adjusting ring 42 has an outer spur gear section 421. This meshes with the corresponding spur gear 511 of a first axial section 51 of an intermediate gear 50. The intermediate gear 50 is designed as a combination gear and, in addition to the aforementioned first axial section 51, additionally comprises a second axial section 52 which is designed like a ring gear. In the embodiment shown, the second axial section 52 is designed in particular like a crown gear, i.e. it has a crown gear 551. A correspondingly toothed drive pinion 60 meshes with this crown toothing 551. Its spur toothing 601 is preferably designed such that the drive pinion 60 can be referred to as a worm, resulting in a self-locking worm drive.This can support the restoring force of the preload spring of the multi-plate clutch 30. The drive pinion 60 is connected to an actuator 70, preferably an electric actuator motor.

[0027] By preferably controlled actuation of the actuator 70, a very precise rotation of the adjusting ring 42 and thus a correspondingly precise axial displacement of the release ring 41 for actuating the multi-plate clutch 30 can be effected via the angular drive between the drive pinion 60 and the second axial section 52 of the second intermediate gear 50 and subsequently via the spur gear stage between the first axial section 51 of the intermediate gear 50 and the spur gearing 421 of the adjusting ring 42.

[0028] Fig. 3 shows a partially sectioned view of the drive arrangement of Fig. 2. The advantageous design of the angular drive between the drive pinion 60 and the second axial section 52 of the intermediate gear 50 as helical gearing with axial offset can be seen. Fig. 3 also clearly shows the fact that the toothed section 421 of the adjusting ring 42 does not extend over its entire circumference, but only over a limited angular range, which is necessary for the axial displacement required to actuate the multi-plate clutch 30. The size of this angular section depends, among other things, on the pitch of the ball ramps 45.

[0029] Fig. 4 shows the drive arrangement of Fig. 2 in a partially sectioned view along section line IV-IV. This figure illustrates the spur gear stage between the first input shaft 11 and the second input shaft 12 arranged parallel to it.

[0030] Of course, the embodiments discussed in the specific description and shown in the figures represent only illustrative embodiments of the present invention. In light of the disclosure herein, a wide range of possible variations is available to the person skilled in the art. List of reference symbols 11 first input shaft 111 spline on 11 112 coupling wheel on 11 12 second input shaft 122 coupling pinion 12 20 Output shaft 201 spline on 20 30 multi-plate clutch 31 outer disc carrier 32 inner disc carriers 33 thrust bearings 40 Ball ramp mechanism 41 Release ring 42 Adjusting ring 421 Gear section of 42 43 Support ring 44 marble run 45 ball ramp 50 intermediate gear 51 first axial section of 50 511 spur gearing of 51 52 second axial section of 50 521 crown toothing of 52 60 drive pinions 601 spur gearing of 60 70 Actuator

Claims

[1] Actuating device for a multi-plate clutch (30), comprising - an axially displaceable release ring (41) connected to a release element (33) acting axially on a disk pack of the multi-disk clutch (30) and - an axially fixed support ring (43) coaxially coupled to the release ring (41) via a ball ramp, one of which is rotatably mounted and provided with a toothed section (421) extending in the circumferential direction and acts as an adjusting ring (42) of a ball ramp mechanism, wherein the toothed section (421) of the adjusting ring (42) meshes with a spur toothing (511) of an intermediate gear (50), which in turn is connected to a drive pinion (60) via a further tooth engagement in a torque-transmitting manner, and wherein the intermediate gear (50) has two axial sections (51, 52), namely - a spur-toothed, first axial section (51) which meshes with the toothed section (421) of the adjusting ring (42) designed as a spur toothing, and - a ring gear-like second axial section (52) which meshes with the correspondingly designed drive pinion (60), characterized by , that the second axial section (52) of the intermediate gear (50) carries a crown toothing (521) which meshes with a corresponding spur toothing (601) of the drive pinion (60), wherein the crown toothing (521) and the spur toothing (601) are helical or curved toothed in a corresponding manner to one another and the drive pinion (60) is designed as a worm. [2] Actuating device according to claim 1, characterized by that the release ring (41) acts as the adjusting ring (42) of the ball ramp mechanism. [3] Actuating device according to one of the preceding claims, characterized bythat the axes of the intermediate gear (50) and the drive pinion (60) are skewed to each other. [4] Drive arrangement for a motor vehicle, comprising a first input shaft (11) connectable to a first drive unit and a coaxially arranged output shaft (20) connectable to an output, which are coupled to one another via a multi-plate clutch (30) actuated by means of an actuating device, characterized by that the actuating device is designed as an actuating device according to one of the preceding claims. [5] Drive arrangement according to claim 4, characterized by that the first input shaft (11) carries a spur-toothed coupling gear (112) which meshes with a coupling pinion (122) arranged on a second input shaft (12) connectable to a second drive unit. [6] Drive arrangement according to claim 5, characterized bythat the two input shafts (11, 12) are arranged axially parallel.

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