CN113027937A

CN113027937A - Friction clutch and clutch system

Info

Publication number: CN113027937A
Application number: CN201911346350.2A
Authority: CN
Inventors: 范意中; 李涛; 周文敏
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2021-06-25

Abstract

The invention relates to a friction clutch and a clutch system. The friction clutch includes: a pressure plate (2) and a counterplate (1) which are arranged coaxially and can be jointly rotated about a rotational axis (X); a spring lever (5) capable of acting on the pressure plate to move the pressure plate axially toward or away from the counterplate; a self-compensating adjustment mechanism comprising: the adjusting mechanism comprises an adjusting ring (8), a ratchet wheel (10), a rotary reversing assembly and a driving spring (11), wherein when the friction clutch is engaged, if the reduction of the distance between the paired plate and the pressure plate exceeds a threshold value, a pawl of the driving spring can drive the ratchet wheel to rotate when the friction clutch is engaged or disengaged again, so that the adjusting ring rotates relative to the pressure plate and the spring lever, and the axial distance between the spring lever and the pressure plate is further adjusted. The clutch system includes at least one friction clutch as described above.

Description

Friction clutch and clutch system

Technical Field

The present invention relates to friction clutches, and more particularly to friction clutches with self-compensating adjustment mechanisms. The invention also relates to a clutch system having the friction clutch.

Background

Conventional clutches change their characteristics when worn. It is therefore advantageously possible to provide a self-compensating adjusting mechanism in an automated friction clutch. Self-compensating adjustment of the clutch usually means that the clutch will compensate itself over the life of the friction lining wear in such a way that the clutch characteristic changes as little as possible or even remains unchanged.

One possible embodiment is a load control clutch. This type of self-compensating regulation compensates by destroying and rebuilding its load-balancing system, the key point being mainly to keep the load-balancing system "as stable as possible". All loads that establish a load balancing system are generated by different types of springs in the clutch, such as various diaphragm springs (lever springs, sensor springs), leaf springs, buffer springs, etc. However, the spring force may not be as stable as desired. The spring force is somewhat susceptible to factors such as the mechanical properties of the spring, geometric variations in the individual parts, vehicle dynamics, etc. In addition, load-adjusting clutches may have other problems, such as the sensitivity of the self-compensating adjustment mechanism.

Another possible embodiment is a travel adjustment clutch. Clutches of this type are adjusted for compensation when a reduction in the thickness of the friction linings, i.e. wear, is detected, with the aim of maintaining the clutch play constant over the entire service life of the clutch. A friction clutch with a wear compensation mechanism of the stroke adjustment type is disclosed, for example, in patent document CN 101230881B. A friction clutch with a self-compensating mechanism of the stroke adjustment type is also known, for example, from CN 101270781B. However, in both of the above friction clutches, the automatic detection of the thickness of the friction lining relies on detecting the movement of the spring lever, and this indirect detection method is affected by the mechanical characteristics of the spring lever, the plate spring, and the clutch cover, and thus has a risk of unreliability.

Disclosure of Invention

The object of the present invention is therefore to provide a friction clutch and a clutch system which have a reliable self-compensating adjusting mechanism.

The above object is achieved by a friction clutch comprising a pressure plate, a counterplate, a spring lever and a self-compensating adjusting mechanism, wherein the pressure plate is arranged coaxially with the counterplate and can be pivoted jointly about a rotational axis, and the spring lever can act on the pressure plate such that the pressure plate is moved axially towards the counterplate or away from the counterplate. According to the design of the invention, the self-compensation adjusting mechanism comprises: an adjusting ring, a ratchet wheel, a rotary reversing assembly and a drive part, wherein the drive part is preferably designed as an elastic drive spring, wherein the spring lever is abutted against a pressure plate by means of the adjusting ring, the adjusting ring can be rotated about a rotational axis and the axial distance between the spring lever and the pressure plate can be adjusted by rotation relative to the pressure plate and the spring lever, wherein the ratchet wheel is mounted on the pressure plate and can be rotated about a further axis intersecting the above-mentioned rotational axis, i.e. the rotational axis of the clutch, wherein the rotary reversing assembly can convert the rotational movement of the ratchet wheel into a rotational movement of the adjusting ring, wherein the drive spring is fixed at one end on the counterplate and at the other end forms a pawl which engages into a ratchet tooth of the ratchet wheel, wherein, when the friction clutch is engaged, if the reduction in the distance between the counterplate and the pressure plate exceeds a threshold value, the pawl can bring the ratchet, so that the adjustment ring rotates relative to the pressure plate and the spring lever.

The friction clutch may also include a clutch cover that is fixedly connected to the counterplate and at least partially surrounds the components in the friction clutch. The pressure plate is located axially between the counterplate and the clutch cover. The pressure plate can be fixed to the clutch cover without relative rotation with respect to the clutch cover, but with limited axial movement. The friction clutch further includes a friction disc disposed axially between the pressure plate and the counter plate. At least one axial side of the friction disk is provided with a friction lining. When the friction clutch is engaged, torque may be transferred from the pressure plate and the counter plate to the friction disc, or from the friction disc to the pressure plate and the counter plate.

In the self-compensating adjusting mechanism, the ratchet wheel is mounted on the pressure plate, the ratchet wheel is not moved in translation relative to the pressure plate, and the ratchet wheel can only rotate about a further axis intersecting the clutch rotation axis. Preferably, the rotational axis of the ratchet wheel and the rotational axis of the clutch are perpendicular to each other. The ratchet teeth of the ratchet wheel may be designed such that the pawl of the drive spring can slide past the ratchet teeth in one circumferential direction of the ratchet wheel, but form-lock with the ratchet teeth in a circumferential direction opposite to the circumferential direction. The rotary reversing assembly may be constructed in accordance with existing solutions, which can transmit rotary motion between the ratchet wheel and the adjusting ring about an alternate axis.

As the friction lining wears, the friction lining thickness decreases and the clutch clearance increases. The self-compensating adjustment of the play can then be carried out by means of the self-compensating adjustment mechanism according to the invention. The compensation adjustment mechanism may detect a geometric change in clutch lash during an on-off cycle of the friction clutch. Specifically, when the friction clutch is engaged, if the distance reduction between the paired plate and the pressure plate exceeds a threshold value, that is, the distance that the pressure plate moves more than the distance when the friction lining is not worn or when the last self-compensation adjustment is just completed during the engagement exceeds the threshold value, the drive spring may drive the ratchet wheel to rotate through two embodiments according to the structural design of the pawl and the ratchet teeth of the ratchet wheel. In one embodiment, the pawl of the drive spring is able to pass or slide past the ratchet tooth when the path of the further movement of the pressure plate exceeds a threshold. When the friction clutch is disengaged again, the ratchet wheel moves together with the pressure plate in a direction away from the counterplate. When the limit position of the driving spring is exceeded, the pawl and the ratchet which the pawl just slides over realize shape locking, and the pawl drives the ratchet wheel to rotate. In another embodiment, when the pressure plate moves more than a threshold value, the pawl of the drive spring cannot pass or slide past the ratchet during the further engagement, i.e. the pawl and the ratchet realize a form-fit. Whereby the pawl of the drive spring can abut against the ratchet teeth of the ratchet wheel and push against the ratchet teeth during continued engagement, thereby causing the ratchet wheel to rotate. The rotating reversing assembly can drive the adjusting ring to rotate relative to the pressure plate and the spring lever, so that the axial distance between the pressure plate and the pairing plate is reduced, and the clutch clearance increased due to friction lining wear is automatically compensated. The self-compensating adjustment process described above can be repeated over the entire service life of the friction clutch. The self-compensating adjusting mechanism thus enables the friction clutch to maintain the clutch play as constant as possible over the entire service life of the friction clutch, even if the friction linings are gradually worn and the thickness is gradually reduced. The load balancing system in the friction clutch is not changed in this case.

Since the fixed end of the drive spring (also referred to as an induction spring) is disposed on the counterplate and the ratchet is disposed on the pressure plate, the drive spring directly detects the gap between the counterplate and the pressure plate, that is, the change of the clutch gap can be directly detected, and the reliability is high. Furthermore, the existing counterplate, which is in this case embodied as a casting, is often used as a flywheel to reduce torque fluctuations. The arrangement of the drive spring on the casting requires less design effort and manufacturing costs than the arrangement of the drive spring on the clutch cover, which is manufactured, for example, by a process such as stamping.

In one advantageous embodiment, the friction clutch is designed as a normally open clutch. Alternatively, the friction clutch is designed as a normally closed clutch. Depending on the design of the friction clutch in the normally open or closed manner, in particular depending on the design of the corresponding clutch actuating device, the installation space in the friction clutch can be used in a targeted manner to arrange the self-compensating adjusting mechanism.

In a preferred embodiment, the rotary reversing assembly is designed as a worm gear assembly, which comprises a worm and worm gear teeth which mesh with a spiral of the worm, wherein the worm extends along the further axis, i.e. the axis of rotation of the ratchet wheel, and is mounted on the pressure plate in a relatively rotatable manner, the worm gear teeth being arranged on the outer circumference of the adjusting ring, wherein the ratchet wheel is fixed to the worm in a rotationally fixed manner. The worm and the ratchet wheel can rotate together. When the worm rotates, the worm gear teeth meshed into the spiral part of the worm drive the adjusting ring to rotate relative to the pressure plate and the spring lever. Rotational movement about the staggered axis can thereby be easily transmitted between the ratchet and the adjustment ring.

In this case, the outer circumference of the adjusting ring is advantageously integrally formed with worm gear teeth. Whereby the assembly steps can be simplified.

In this case, alternatively and advantageously, the worm gear assembly further comprises a toothed ring which is fixed to an outer circumferential section of the adjusting ring, the outer circumference of the toothed ring being configured with worm gear teeth. The adjusting ring and the toothed ring may be riveted, screwed or welded. In this case, the axial action mechanism of the adjusting ring can be designed separately from the worm gear structure, both of which can be designed separately and manufactured separately, and finally the coupling is achieved by assembly.

In this case, the worm is preferably mounted on the pressure plate via a bracket. The rotatable mounting of the ratchet and the worm is thereby achieved in a simple and reliable manner. In addition, the position of the worm and the ratchet wheel relative to the pressure plate can be adjusted through the bracket.

In a preferred embodiment, at least one axial end face of the adjusting ring is provided with a ramp which interacts with the spring lever and/or the pressure plate. That is, the axial mechanism of action of the adjusting ring is achieved by relative displacement of the ramp structure of the adjusting ring and the mating structure of the spring lever and/or pressure plate facing the axial side of the ramp. The mating structure may be at least partially non-planar structures on the spring levers and/or the pressure plate. The ramp is displaced relative to the mating structure as the adjustment ring is rotated relative to the spring lever and the pressure plate. This makes it possible to keep the clutch play constant, while keeping the spring lever load substantially constant.

In a preferred embodiment, the drive springs are arranged radially outside the counterplate and the pressure plate. The space radially outside the counterplate and the pressure plate can thereby be utilized. In addition, the drive spring can be implemented with a simple structure and small size.

In this case, the drive spring is advantageously fastened to an axial side of the counterplate facing away from the pressure plate. The drive spring can thereby be stably mounted and is advantageous for efficiently driving the ratchet wheel in rotation.

The above object is also achieved by a clutch system comprising at least one friction clutch as described above. The clutch system may be used in a hybrid vehicle, a pure electric vehicle or a vehicle driven by an internal combustion engine. The clutch system may be a dual clutch system or a triple clutch system.

Drawings

Preferred embodiments of the present invention are schematically illustrated in the following with reference to the accompanying drawings.

Fig. 1 shows a schematic half-section of a friction clutch according to a preferred embodiment.

Detailed Description

Friction clutches are used, for example, in vehicles to controllably transmit torque output by an internal combustion engine to a transmission. The friction clutch according to the present embodiment is designed as a normally open clutch. The friction clutch has a counterplate 1, a friction disc 3 and a pressure plate 2 arranged in succession along the same axis of rotation X. The friction clutch further has a clutch cover 4, and the clutch cover 4 is bolted to the opposing plate 1 at the radially outer end. The clutch cover 4 is bell-shaped, so that the clutch cover 4 and the counterplate 1 together form a space for accommodating the friction disks 3 and the pressure plate 2.

The counterplate 1 can be connected to a crankshaft of an internal combustion engine, not shown, in order to transmit the torque of the internal combustion engine to the friction clutch. The counterplate 1 is in this case designed as a cast part, which in this case also serves as a flywheel, in order to reduce the rotational speed fluctuations that occur during operation of the internal combustion engine. The pressure plate 2 and the counterplate 1 can jointly be rotated about the axis of rotation X. Friction linings are respectively arranged on the two axial sides of the friction disc 3. When the pressure plate 2 is actuated by the clutch actuation device, the pressure plate 2 is moved axially toward the counterplate 1 until the friction disks 3 are pressed between the counterplate 1 and the pressure plate 2, so that a frictional engagement of the friction clutch is achieved. The torque of the counterplate 1 and the pressure plate 2 is thereby transmitted to the friction disc 3. The friction discs 3 are in turn connected in a rotationally fixed manner to the transmission input shaft 15, whereby the torque is further transmitted to the transmission.

The clutch actuation device comprises a spring lever 5 and a not shown, for example, hydraulic actuator. The spring lever 5 can be designed as a conventional diaphragm spring. The spring lever 5 is mounted on the clutch cover 4 so as to be axially movable relative to one another by means of a centering bolt 6. The spring lever 5 rests at a radially outer section on the clutch cover 4 via a bearing ring 7 serving as a fulcrum, and the diaphragm spring 5 rests with its axial side facing away from the bearing ring 7 on the adjusting ring 8 at a radially inner side relative to the bearing ring 7. The adjusting ring 8 in turn bears with its axial side facing away from the spring lever 5 against the pressure plate 2. When the hydraulic actuator actuates the radially inner section of the spring lever 5, the spring lever 5 thus pushes the adjusting ring 8 and thus the pressure plate 2 toward the counterplate 1 by leverage.

The friction clutch further includes a self-compensating adjustment mechanism. The self-compensating adjustment mechanism is also disposed in the accommodation space formed by the clutch cover 4 and the counterpart plate 1. The self-compensation adjusting mechanism comprises an adjusting ring 8, a toothed ring, a worm 9, a ratchet wheel 10 and a drive spring 11. As described above, the adjusting ring 8 is arranged axially between the pressure plate 2 and the spring lever 5. The adjusting ring 8 is provided with a slope on the axial side facing the pressure plate 2. The ramp can adjust the axial distance between the pressure plate 2 and the spring lever 5 in cooperation with, for example, a projection of the pressure plate 2 on the axial side facing the adjusting ring 8 when the adjusting ring 8 is rotated relative to the pressure plate 2. The adjusting ring 8 is riveted with the toothed ring at its outer circumferential section. The outer periphery of the ring is configured with worm gear teeth 13. The worm 9 extends in a direction perpendicular to the axis of rotation X, and the worm 9 is relatively rotatably mounted on the platen 2 by means of a bracket 14. The worm 9 is arranged on the axial side of the pressure plate 2 facing away from the counter plate 1 and is located radially close to the outside of the pressure plate 2. The spiral 12 of the worm 9 meshes with the worm gear teeth 13. The ratchet 10 is fixed in a rotationally fixed manner on the worm 9. One end of the drive spring 11 is fixed on the axial side of the counterplate 1 facing away from the pressure plate 2. The other end of the drive spring 11 forms a pawl which engages into the ratchet teeth of the ratchet 10. The ratchet teeth of the ratchet 10 can be designed here such that the pawl of the drive spring 11 can slide past the ratchet teeth in the clockwise direction of the ratchet 10 shown with reference to fig. 1, but cannot slide past the ratchet teeth in the counterclockwise direction.

When the friction linings on both sides of the friction disc 3 wear, i.e. become thinner, the clutch clearance increases. The self-compensating adjustment mechanism may detect a geometric change in clutch lash during an on-off cycle of the friction clutch. Specifically, with the normally open friction clutch of the present embodiment, the pressure plate 2 needs to be moved through a further stroke during engagement to engage the friction clutch. In the case of the engagement of the friction clutch, if the distance between the counterplate 1 and the pressure plate 2 decreases by more than a threshold value, i.e. the distance over which the pressure plate 2 moves exceeds a threshold value, the pawl of the drive spring 11 cannot pass or slide past the ratchet during the further engagement, i.e. the pawl and the ratchet achieve a positive lock. The pawl of the drive spring 11 can thereby abut against the ratchet teeth of the ratchet 10 and push against them during continued engagement, thereby bringing the ratchet 10 to rotate in the clockwise direction with reference to the ratchet 10 shown in fig. 1. In a further embodiment, the ratchet configuration can also be configured differently from the ratchet shown in fig. 1, where the pawl of the drive spring 11 is able to pass over a ratchet, i.e. slide over an adjacent ratchet in the clockwise direction with reference to the ratchet 10 shown in fig. 1, when the pressure plate 2 has moved more than a threshold. When the friction clutch is disengaged again, the ratchet 10 moves together with the pressure plate 2 in a direction away from the counterplate 1. Beyond the limit position of the drive spring 11, the ratchet tooth that the pawl has just slipped applies a force to the pawl, whereby the pawl drives the ratchet 10 to rotate by a reaction force. When the ratchet 10 rotates, the worm 9 rotates along with the ratchet 10. When the worm 9 rotates, the worm teeth 13, which engage in the spiral 12 of the worm 9, bring about a rotation of the toothed ring and of the adjusting ring 8 relative to the pressure plate 2. The adjustment ring 8, by means of its ramp structure, interacts with the projection of the pressure plate 2 to increase the axial distance between the pressure plate 2 and the spring lever 5, thereby reducing the axial distance between the pressure plate 2 and the counterplate 1 and compensating for the increased clutch play due to friction lining wear.

The self-compensating adjustment process described above can be repeated over the entire service life of the friction clutch with respect to the initial state or the last self-compensating adjustment. The self-compensating adjusting mechanism thus enables the friction clutch to maintain the clutch play as constant as possible over the entire service life of the friction clutch, even if the friction linings are gradually worn and the thickness is gradually reduced.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

1 paired board

2 pressing plate

3 friction disk

4 Clutch cover

5 diaphragm spring

6 centering bolt

7 support ring

8 adjusting ring

9 Worm

10 ratchet wheel

11 drive spring

12 helical part

13 toothed ring

14 support

15 speed variator input shaft

X axis of rotation

Claims

1. A friction clutch comprising:

-a platen (2) and a counterplate (1), said platen (2) being arranged coaxially with said counterplate (1) and being jointly rotatable about an axis of rotation (X);

-a spring lever (5), said spring lever (5) being capable of acting on said pressure plate (2) so that said pressure plate (2) moves axially towards said counter plate (1) or away from said counter plate (1),

-a self-compensating adjustment mechanism for adjusting the position of the actuator,

characterized in that, the self-compensating adjustment mechanism includes:

-an adjusting ring (8), by means of which adjusting ring (8) the spring lever (5) abuts against the pressure plate (2), which adjusting ring (8) is rotatable about the axis of rotation (X) and adjusts the axial distance between the spring lever (5) and the pressure plate (2) by relative rotation;

-a ratchet (10), said ratchet (10) being mounted on said platen (2) and said ratchet (10) being rotatable about a further axis intersecting said rotation axis (X);

-a rotary reversing assembly able to transform the rotary motion of the ratchet (10) into a rotary motion of the adjusting ring (8);

-a driving member (11), said driving member (11) being fixed at one end to said counterplate (1) and at the other end forming a pawl to be engaged in a ratchet of said ratchet (10);

when the friction clutch is engaged, if the distance between the paired plates (1) and the pressure plate (2) is reduced by more than a threshold value, the pawl can drive the ratchet wheel (10) to rotate when the friction clutch is engaged or disengaged again, so that the adjusting ring (8) rotates relative to the pressure plate (2) and the spring lever (5).

2. The friction clutch as claimed in claim 1, characterized in that the friction clutch is designed as a normally open clutch or as a normally closed clutch.

3. The friction clutch according to claim 1, characterized in that the rotary reversing assembly is configured as a worm gear assembly comprising a worm (9) and worm gear teeth (13) meshing with the worm (9), wherein the worm (9) extends along the axis of rotation of the ratchet wheel (10) and is mounted on the pressure plate (2) rotatably relative thereto, the worm gear teeth (13) being arranged on the outer circumference of the adjusting ring (8), wherein the ratchet wheel (10) is fixed on the worm (9) in a rotationally fixed manner.

4. The friction clutch of claim 3 wherein the adjusting ring is integrally configured with the worm gear teeth on its outer periphery.

5. The friction clutch according to claim 3, characterized in that the worm gear assembly further comprises a toothed ring fixed to an outer peripheral section of the adjusting ring (8), the outer periphery of the toothed ring being configured with the worm gear teeth (13).

6. The friction clutch according to claim 3, characterized in that the worm (9) is mounted on the pressure plate (2) by means of a bracket (14).

7. The friction clutch according to claim 1, characterized in that at least one axial end face of the adjusting ring (8) is provided with a ramp cooperating with the spring lever (5) and/or the pressure plate (2).

8. The friction clutch according to claim 1, characterized in that the driving member (11) is arranged radially outside the counterplate (1) and the pressure plate (2).

9. The friction clutch according to claim 8, characterized in that the drive part (11) is fixed on an axial side of the counterplate (1) facing away from the pressure plate (2).

10. Clutch system comprising at least one friction clutch according to any one of claims 1-9.