JP4414835B2 - Clutch cover assembly - Google Patents

Description

  The present invention relates to a clutch cover assembly, and more particularly to pressing and releasing a friction member of a clutch disassembly against a flywheel of an engine.

  The clutch cover assembly is generally mounted on an engine flywheel and used to transmit the driving force of the engine to the transmission side. Such a clutch cover assembly mainly includes a clutch cover fixed to the flywheel, a pressure plate for sandwiching the friction member of the clutch disk assembly between the flywheel, and the pressure plate on the flywheel side. It is comprised from the diaphragm spring for pressing. The diaphragm spring includes an annular elastic portion and a plurality of lever portions extending radially inward from the inner peripheral edge of the annular elastic portion. The diaphragm spring has a function of pressing the pressure plate and a lever function for releasing the pressure on the pressure plate.

  The pressing load characteristic of the clutch cover assembly will be described. The pressing load characteristic represents a use area as a pressing load in the load characteristic of the diaphragm spring. For example, as shown in FIG. 6, in the pressing load characteristic 20, the effective use area (wear allowance) of the clutch cover assembly is an area where a constant pressing load can be obtained (from the new set line 25 to the wear limit of the friction member). To the wear line 26).

  Next, the release load characteristics of the clutch cover assembly will be described. The release load characteristic represents the relationship between the operation amount (lever stroke amount) of the release lever and the load (release load) acting on the tip of the release lever. For example, as shown in FIG. 9, the release load characteristic 60 has a first portion 61 that increases linearly from zero lever operation amount, and a second portion 62 that gradually decreases. The point of contact between them is a peak 63. The first portion 61 represents the lever rigidity of the diaphragm spring, and the second portion 62 corresponds to a change in the pressing load characteristic from the set line to the right side in the figure.

  As shown in FIG. 6, the pressing load characteristic 20 increases at a constant rate as the displacement amount of the diaphragm spring increases from zero. However, when the deflection amount exceeds a certain point (peak point), the pressing load characteristic 20 gradually increases. It decreases gradually, and when it exceeds a certain amount of deflection, it gradually increases. For this reason, in the effective use area | region, it is the peak part 21 (part which becomes convex upward), and the pressing load becomes large as wear of a friction member becomes large (as a set line moves to the left side of a figure). . That is, when the friction member wears, the release load increases and the clutch pedal depression force also increases.

Therefore, conventionally, as a structure for cutting the peak in the pressing load characteristic, a peak cut clutch using an elastic member that generates a load that acts to counteract the load of the diaphragm spring when the friction member is worn is known. Yes. In the peak cut clutch, the peak portion of the diaphragm spring is overlapped with the peak portion characteristic opposite to that of the elastic member, and as a result, a flat portion is obtained in the combined load (see, for example, Patent Document 1). ).
ACT 3-22131

  The reduction of the release load by the cushioning function in the friction member will be described. When there is no cushioning function, in the release load characteristic of FIG. 9, the release load characteristic 60 linearly changes up to the load balance point 63, and gradually decreases and increases gradually. Further, the pressure plate has a zero cut amount up to the load balance point 63. When the friction member has a cushion function, the pressure plate starts moving at the same time as the release starts due to the repulsive force of the cushion, and moves to some extent at the load balance point 63. This means that the pressing load at the load balance point is shifted to the right in FIG. As a result, the release load at the load balance point 63 in FIG. 9 is significantly smaller than when there is no cushioning function. The above result is obtained because the pressure plate moves in the negative gradient portion during the release operation in the pressing load characteristic of FIG. Therefore, if the position of the set line changes due to wear of the friction member, it may be possible to move the flat portion or the positive gradient portion. In that case, a low release load due to the cushioning function in the friction member cannot be obtained.

  An object of the present invention is to realize a low release load by a cushioning function in a friction member even when the friction member is worn.

  A clutch cover assembly according to claim 1 is for pressing and releasing a friction member with a cushioning function of a clutch disassembly against an engine flywheel, the clutch cover, a pressure plate, and a diaphragm spring. And a first elastic member and a second elastic member. The clutch cover is fixed to the flywheel. The pressure plate is connected to the clutch cover so as not to rotate relative to the clutch cover, and is a member for sandwiching the friction member with the flywheel. The diaphragm spring is supported by the clutch cover and biases the pressure plate toward the flywheel. The first elastic member is a member that is supported by the clutch cover and generates a load that opposes the urging force of the diaphragm spring, thereby flattening a change in the pressing load on the pressure plate with respect to the displacement amount of the diaphragm spring. . The second elastic member is supported by the clutch cover, and generates a load that opposes the urging force of the diaphragm spring during the release operation. In this process, the displacement amount of the diaphragm spring increases due to the cushioning function of the friction member. It is a member for reducing the pressing load to the.

  In this clutch cover assembly, the change of the pressing load on the pressure plate with respect to the displacement amount of the diaphragm spring is flattened by the first elastic member. Next, with the second elastic member, the release load can be reduced by the cushioning function of the friction member even when the friction member is worn. The second elastic member generates a load that opposes the urging force of the diaphragm spring during the release operation, thereby reducing the pressing load on the pressure plate in the process of increasing the displacement amount of the diaphragm spring by the cushioning function of the friction member. Because it goes.

  In a clutch cover assembly according to a second aspect, in the first aspect, the second elastic member increases the load as the release operation proceeds from the clutch connected state.

  According to a third aspect of the present invention, in the clutch cover assembly according to the first or second aspect, the second elastic member is configured by combining a plurality of elastic members.

  In this clutch cover assembly, preferable characteristics can be realized by a plurality of elastic members.

  In a clutch cover assembly according to a fourth aspect, in any one of the first to third aspects, the second elastic member is disposed on the side opposite to the friction member side of the clutch cover in the axial direction.

  In this clutch cover assembly, the second elastic member can be easily assembled and removed.

According to a fifth aspect of the present invention, the clutch cover assembly according to the fourth aspect further includes a support member extending from the pressure plate to the clutch cover side. The second elastic member applies a load to the support member on the friction member side and the axially opposite side.

  According to a sixth aspect of the present invention, in the clutch cover assembly according to the first aspect, the second elastic member is a cone spring.

  According to a seventh aspect of the present invention, the clutch cover assembly according to the first aspect further includes a wear compensation mechanism for maintaining the posture of the second elastic member against the wear of the friction member.

  In this clutch cover assembly, the posture of the second elastic member is maintained by the wear compensation mechanism even when the friction member is worn.

  The clutch cover assembly according to claim 8, wherein the wear compensation mechanism has a return mechanism for returning the second elastic member to a pre-wear position when the friction member is worn. .

  In this clutch cover assembly, the second elastic member is returned to the original posture by the return mechanism.

According to a ninth aspect of the present invention, in the clutch cover assembly according to the eighth aspect, the return mechanism includes a support member that extends from the pressure plate toward the clutch cover side, and a screw that engages the support member with a screw and friction from the second elastic member. and support and engagement member for receiving a load to member side axially opposite the third the support and engagement member imparts always torque to the support engaging member to rotate in a direction to move the friction member side axially opposite And an elastic member.

  In this clutch cover assembly, the support engagement member is positioned in the axial direction with respect to the support member by the load balance between the second elastic member and the third elastic member. When the friction member wears in this state, the support portion and the support engagement member move to the axial engine side together with the pressure plate, and the posture of the second elastic member is changed. As a result, the load balance is lost, and the support engagement member moves relative to the support member until the load balance between the second elastic member and the third elastic member is achieved. As a result, the second elastic member returns to the original posture.

  A clutch cover assembly according to a tenth aspect is the clutch cover assembly according to the seventh aspect, wherein the wear compensation mechanism is frictionally engaged with the support member, the support member extending from the pressure plate to the clutch cover side at a position different from the second elastic member. And a friction engagement member to which a load is applied from the second elastic member.

  In this clutch cover assembly, when the friction member wears in the clutch engaged state, the support member moves to the friction member side together with the pressure plate. At this time, the frictional engagement member slips because the end portion thereof abuts against the clutch cover in the clutch engaged state. Therefore, even if the friction member is worn, the posture of the second elastic member does not change. That is, the load characteristic of the second elastic member does not change due to wear of the friction member. Moreover, although the load from a 2nd elastic member acts with respect to the friction engagement part of a support member and a friction engagement member, there does not slip. Here, in particular, since the friction engagement member is inclined, the friction engagement portion is also inclined to generate a large amount of friction. As described above, in the friction engagement portion composed of the support member and the friction engagement member, the resistance acting on the support member at the time of clutch release is made smaller than the resistance acting on the support member at the time of clutch release. The pressing load on the pressure plate can be prevented from being reduced while maintaining the characteristics of the member.

  In the clutch cover assembly according to the present invention, a low release load can be realized by the cushioning function of the friction member even when the friction member is worn.

(1) Overall Structure of Clutch Cover Assembly The pull type diaphragm spring type clutch cover assembly 1 shown in FIGS. 1 to 3 presses the friction member 53 of the clutch disc assembly 52 against the flywheel 51 of the engine. This is a device for disengaging the clutch by connecting or releasing the clutch. The friction member 53 includes a friction facing 53a and a cushioning plate 53b, and has a cushioning function that can be deflected within a predetermined range in the axial direction.

  The OO line shown in FIGS. 1 and 2 is the rotational axis of the flywheel 51 and the clutch cover assembly 1. Hereinafter, the left side of the figure is referred to as the axial engine side, and the right side of the figure is referred to as the axial transmission side.

  The clutch cover assembly 1 is mainly composed of a clutch cover 2, a pressure plate 3, and a diaphragm spring 4.

  The clutch cover 2 is a substantially dish-shaped plate member, and an outer peripheral portion thereof is fixed to the flywheel 51 by bolts, for example. The clutch cover 2 has a disk-shaped portion that faces the outer peripheral portion of the flywheel 51 with a gap in the axial direction.

  The pressure plate 3 is an annular member having a pressing surface 3 a formed on the side facing the flywheel 51. Between the pressing surface 3a and the flywheel 51, the friction member 53 of the clutch disk assembly 52 is disposed. The pressure plate 3 is formed with an annular protrusion 3b that protrudes in the axial direction on the side opposite to the pressing surface 3a. The pressure plate 3 is connected to the clutch cover 2 by a plurality of strap plates 7 so as to be movable in the axial direction but not relatively rotatable.

  The diaphragm spring 4 is a disk-shaped member disposed between the pressure plate 3 and the clutch cover 2, and includes an annular elastic portion 4a and a plurality of lever portions extending radially inward from the inner peripheral portion of the annular elastic portion 4a. 4b. The inner peripheral portion of the annular elastic portion 4 a is in contact with the protruding portion 3 b of the pressure plate 3. The outer peripheral portion of the annular elastic portion 4 a is supported by the clutch cover 2 via the wire ring 5. In this state, the annular elastic portion 4a biases the pressure plate 3 toward the flywheel 51. A slit is formed between the lever portions 4b of the diaphragm spring 4, and an oval hole 4c is formed in the outer peripheral portion of the slit. A pull-type release device (not shown) is engaged with the tip of the lever portion 4 b of the diaphragm spring 4. This release device is composed of a release bearing or the like.

(2) First Low Release Load Characteristics Realizing Mechanism Next, the first low release load characteristics realizing mechanism 8 will be described. The first low release load characteristic realizing mechanism 8 is a mechanism for realizing a low release load characteristic even when wear of the friction member 53 progresses by achieving flattening of the pressing load characteristic. The mechanism 8 includes a first unit 9 and a second unit 10 that are arranged side by side in the circumferential direction. Two each of the first unit 9 and the second unit 10 are provided, and are arranged alternately in the circumferential direction. For this reason, the mechanism 8 generates a load in a balanced manner in the circumferential direction.

  As shown in FIG. 1, the first unit 9 includes a support bolt 12, a spring seat 13, and two cone springs 14. The support bolt 12 extends from the inner peripheral portion of the pressure plate 3 on the protruding portion 3b side to the axial transmission side. The support bolt 12 has a trunk portion 12a and a head portion 12b. The trunk portion 12 a of the support bolt 12 extends further in the axial direction through the oblong hole 4 c of the diaphragm spring 4. In the clutch cover 2, a hole 16 is formed at a position corresponding to the support bolt 12. The hole 16 has a circular shape larger than the oval hole 4c. The trunk portion 12 a of the support bolt 12 extends further in the axial direction through the hole 16, and as a result, the head portion 12 b of the support bolt 12 is located on the axial transmission side with respect to the clutch cover 2. The spring seat 13 is a washer-like member, and is disposed in contact with the surface on the axial direction engine side of the head 12 b of the support bolt 12. The cone spring 14 is arranged so that two springs act in parallel, and is arranged on the clutch cover 2 on the axial transmission side of the hole 16. A preferable load can be generated in each unit 9 by combining each spring. The cone spring 14 has an outer peripheral edge supported by an edge portion of the hole 16 of the clutch cover 2. A support ring 17 is fixed around the hole 16 of the clutch cover 2 by a fixing member 18. The support ring 17 is close to the axial transmission side of the outer peripheral portion of the cone spring 14. Therefore, the outer peripheral edge of the cone spring 14 cannot be moved greatly in the axial direction with respect to the clutch cover 2. The inner peripheral edge of the cone spring 14 is supported by the spring seat 13. When the clutch is not worn, the cone spring 14 does not generate a load when the clutch is engaged. On the other hand, when the friction member 53 of the clutch disk assembly 52 is worn, the pressure plate 3 and the support bolt 12 move to the axial engine side, so that the cone spring 14 is compressed between the clutch cover 2 and the spring seat 13, A load is applied to both members in the axial direction. The load applied by the cone spring 14 to the support bolt 12 or the like acts on the side opposite to the pressing load applied to the pressure plate 3 by the diaphragm spring 4, thereby reducing the pressing load and consequently reducing the release load. Realized (described later).

  The second unit 10 has the same basic structure as the first unit 9. However, as shown in FIG. 5, a gap is secured in the axial direction between the inner peripheral edge of the cone spring 14 and the spring seat 13. That is, the cone spring 14 of the second unit 10 does not generate a load at the initial stage of wear of the friction member 53. In other words, the compression start timing of the cone spring 14 of the second unit 10 is shifted from the compression start timing of the cone spring 14 of the first unit 9.

  The pressing load characteristic of FIG. 6 will be described. The characteristic 20 of the diaphragm spring 4 has a peak portion 21 as already described. On the other hand, the characteristic 22 of the cone spring 14 of the first unit 9 and the characteristic 23 of the cone spring 14 of the second unit 10 have opposite mountain portions (portions protruding downward) that cancel the portion 21. The composite load flat portion 24 is formed. More specifically, the cone spring 14 of the first unit 9 generates a load from the set line 25, and the valley portion is located at the end of the wear allowance. The cone spring 14 of the second unit 10 generates a load after being somewhat displaced from the set line 25, and the valley portion is somewhat displaced from the end of the wear allowance. As described above, the combined load flat portion 24 having a sufficiently large wear allowance is realized by using two types of cone springs in combination. Thereby, even when the friction member 53 is worn, the clutch pedal depressing force is hardly changed compared to when the friction member 53 is not worn, and the operation feeling during the release operation is improved.

(3) Second Low Release Load Characteristic Realization Mechanism The second low release load characteristic realization mechanism 30 will be described with reference to FIGS. 2 and 3. The second low release load characteristic realizing mechanism 30 is a release assisting mechanism for realizing the low release load by the cushioning function in the friction member 53 even when the friction member 53 is worn. First, the reduction in the release load by the cushioning function in the friction member will be described with reference to FIG. When there is no cushioning function, the release load characteristic 60 changes linearly up to the peak, that is, the load balance point 63, and gradually decreases and increases gradually. Further, the pressure plate breakage 65 is zero up to the load balance point 63. When the friction member has a cushion function, the pressure plate moves quickly at the time of release, and the pressure plate breakage amount 65 increases faster than when there is no cushioning plate. Further, the peak at the load balance point 63 in FIG. 9 is significantly reduced, and a low release load characteristic is realized. The above result is obtained because the position of the pressure plate moves in the negative gradient direction (right direction) in the pressing load characteristic of FIG. 6 during the release operation. Therefore, if the position of the set line changes due to wear of the friction member, the pressure plate may move in a flat portion or a positive gradient portion during the release operation. Therefore, the second low release load characteristic realizing mechanism 30 realizes that the pressure plate moves in the negative gradient direction of the load characteristic even when the friction member is worn.

  The second low release load characteristic realizing mechanism 30 is alternately arranged in the same radial direction position as the first unit 9 and the second unit 10 of the first low release load characteristic realizing mechanism 8. The second low release load characteristic realizing mechanisms 30 are arranged in a total of four places. As shown in FIG. 4, each mechanism 30 includes a second support bolt 31, a holder 32, a first support member 33, a snap ring 34, a second support member 35, and a pair of first cone springs 36. The second cone spring 37 and the support ring 38 are included.

  The second support bolt 31 extends from the surface of the pressure plate 3 on the protruding portion 3b side to the axial transmission side. The second support bolt 31 has a trunk portion 31a, a screw portion 31b, and a head portion 31c in this order. The body portion 31a passes through the oval hole 4c of the diaphragm spring 4 in the axial direction. The screw part 31 b is a part in which a screw is formed in a spiral shape on the surface, and is disposed in the hole 11 formed in the clutch cover 2. The hole 11 has a substantially circular shape. The head portion 31c is formed longer in the axial direction, and an adjustment spring 39 is wound around the head portion 31c (described later).

  The holder 32 is a cylindrical member and includes a cylindrical portion 32a and a flange portion 32b. A screw 32d that is screwed into the screw portion 31b is formed on the inner peripheral surface of the cylindrical portion 32a. In addition, in the state of FIG. 4, the screw part 31b is also formed in the axial direction transmission side rather than the cylinder part 32a. The flange portion 32b extends from the axial transmission side end of the cylindrical portion 32a to the outer peripheral side. A plurality of holes 32c penetrating in the axial direction are formed in the flange portion 32b.

  The first support member 33 is a cylindrical member and is disposed on the outer periphery of the holder 32. A snap ring 34 is fitted on the outer peripheral surface of the end of the holder 32 on the axial direction engine side, and the first support member 33 maintains a slight gap with respect to the holder 32 by the snap ring 34 in the axial direction. It is held immovable. In addition, a radial clearance is secured between the inner peripheral surface of the first support member 33 and the outer peripheral surface of the holder 32, so that both can rotate relative to each other. The second support member 35 is a cylindrical member, and is firmly fixed to the outer peripheral surface of the axial direction engine side portion of the first support member 33 by screws or caulking. As described above, the holder 32, the first support member 33, and the second support member 35 have one structure that moves integrally in the axial direction. The first support member 33 has an annular protrusion 33a extending to the outer peripheral side, and the second support member 35 has an annular protrusion 35a extending to the outer peripheral side.

  The pair of first cone springs 36 are arranged so as to act in parallel, the inner peripheral edge is in contact with the annular protrusion 33a of the first support member 33 from the axial engine side, and the outer peripheral edge is a support ring. 38 abuts from the axial transmission side. The support ring 38 is fixed to the axial transmission side around the hole 11 of the clutch cover 2 by a fixing member 19. The second cone spring 37 is in contact with the annular protrusion 35a of the second support member 35 from the axial transmission side at the inner peripheral edge, and is in contact with the support ring 38 from the axial engine side at the outer peripheral edge. As described above, the first cone spring 36 can apply a load to the axial transmission side with respect to the structure including the holder 32 and the like, and the second cone spring 37 is applied to the structure including the holder 32 and the like. It is possible to apply a load to the axial engine side. The cone springs 36 and 37 hardly apply a load to the holder 32 and the like when the clutch is engaged, but apply a load to the holder 32 and the like on the axial transmission side during the clutch release operation to reduce the release load. That is, the load of the first cone spring 36 is larger than the load of the second cone spring 37.

  Since the cone springs 36 and 37 are arranged on the side of the clutch cover 2 in the axial direction, assembly and removal are easy.

  The adjustment spring 39 is a torsion coil spring, wound around the head portion 31c of the second support bolt 31, and has one end engaged with the head portion 31c. Further, the engagement end 39 a of the adjustment spring 39 is inserted into the hole 32 c of the holder 32 and engaged therewith. As a result, the adjustment spring 39 applies a substantially constant load to the holder 32 on one side in the rotational direction. The direction in which the load is applied from the adjustment spring 39 is a direction in which the holder 32 moves toward the axial transmission side along the screw portion 31b.

  The operation of the second low release load characteristic realizing mechanism 30 will be described. As shown in FIG. 7, the characteristic 43 of the first cone spring 36 generates a load toward the positive side (axial transmission side), and the characteristic 44 of the second cone spring 37 has a negative side (shaft). A load is generated toward the direction engine side). The characteristic 43 of the first cone spring 36 has a large difference between the valley and the peak and has a large gradient, and the characteristic 44 of the second cone spring 37 has a small difference between the valley and the peak and has a small gradient. In the composite characteristic 45, the valley portion is disposed at the clutch engagement position, and the load there is zero. The valley load of the composite characteristic 45 is preferably designed to be zero or less. When moving from zero load to the maximum release position, the load gradually increases to the positive side. In view of the set load characteristics shown in FIG. 8, when the release operation is performed after the friction member 53 is worn, the set line is shifted to the large displacement side like lines 47 and 48 by the cushion function in the friction member 53. In other words, a negative gradient is always ensured in the pressing characteristics, and therefore a low release load is reliably realized by the cushion function.

  In the clutch engaged state, the force (torque) for rotating the holder 32 by the adjustment spring 39 is balanced with the frictional force of the thread surface due to the combined load (axial load) of the cone springs 36 and 37. The axial load applied to the support bolt 31 is slightly larger than zero. When the friction member 53 is worn, the second support bolt 31, the holder 32, etc. move to the axial engine side. Then, the cone springs 36 and 37 are deformed, and the load of these members is reduced to zero. At that time, the adjustment spring 39 rotates the holder 32 and moves it to the axial engine side. Then, the combined load in the axial direction by the cone springs 36 and 37 increases, and the frictional force of the thread surface increases in direct proportion thereto. Therefore, it becomes impossible to rotate the holder 32 by the torque of the adjustment spring 39, The axial movement of the holder 32 stops. Thus, even if the friction member 53 is worn, the postures of the cone springs 36 and 37 in the second low release load characteristic realizing mechanism 30 are returned to the original state. As a result, the postures of the cone springs 36 and 37 are maintained even when the friction member 53 is worn, and the load of the second low release load characteristic realizing mechanism 30 is maintained constant.

(4) Clutch connection / release operation In this clutch cover assembly 1, the annular elastic portion 4 a presses against the pressure plate 3 while a release device (not shown) does not apply a load to the tip of the lever portion 4 b of the diaphragm spring 4. Is given. As a result, the friction member 53 of the clutch disk assembly 52 is pressed against the flywheel 51, and torque is transmitted to the clutch disk assembly 52 (clutch engagement state).

  When a release device (not shown) pulls out the tip of the lever portion 4b of the diaphragm spring 4 to the transmission side, the inner peripheral portion of the annular elastic portion 4a of the diaphragm spring 4 is lifted to the axial transmission side with the wire ring 5 as a fulcrum. Thereby, the annular elastic portion 4a does not press the pressure plate 3, the pressure plate 3 is pulled away from the friction member 53 by the strap plate 7, and finally the friction member 53 is separated from the flywheel 51 (clutch release state).

(5) Another Example of Second Low Release Load Characteristic Realization Mechanism The second low release load characteristic realization mechanism 71 will be described with reference to FIG. The second low release load characteristic realizing mechanism 71 is a mechanism for realizing the same function as the mechanism 30 of the above-described embodiment, and is provided on the clutch cover 72. FIG. 10 shows the clutch engaged state.

  The support bolt 73 extends from the pressure plate to the axial transmission side as in the above embodiment. The body 73 a of the support bolt 73 passes through a hole 72 a formed in the clutch cover 72. As a result, a part of the trunk portion 73a and the head portion 73b are located on the axial transmission side of the clutch cover 72.

  The spring unit 75 is disposed on the transmission side in the axial direction of a circular hole 72b formed in the clutch cover. The spring unit 75 is disposed at substantially the same radial position as the support bolt 73. The spring unit 75 includes a pair of a first cone spring 77, a second cone spring 78, a spring seat 79, a snap ring 80, a first member 81, and a second member 82. The spring seat 79 is a cylindrical member seated around the hole 72 b of the clutch cover 72. The first member 81 and the second member 82 are disposed in the hole 72b and are firmly fixed to each other by screws. The first member 81 has an annular protrusion 81a extending to the outer peripheral side, and the second member 82 has a portion 82b facing the protrusion 81a with a gap in the axial direction.

  The inner peripheral edges of the first cone spring 77 and the second cone spring 78 are disposed in the space between the first member 81 and the second member 82. Specifically, the inner peripheral edge of the first cone spring 77 is in contact with the protrusion 81a of the first member 81 from the axial engine side. The inner peripheral edge of the second cone spring 78 is in contact with the portion 82b of the second member 82 from the axial engine side. The outer peripheral edges of the first cone spring 77 and the second cone spring 78 are supported by a spring seat 79. Specifically, a snap ring 80 is fixed to the inner peripheral surface of the end of the spring seat 79 on the axial transmission side to limit the movement of the cone springs 77 and 78 toward the engine in the axial direction. The outer peripheral edge of the second cone spring 78 is in contact with an inner peripheral protrusion 79a formed on the axial engine side of the spring seat 79 from the axial transmission side. A wire ring is disposed between the outer peripheral edge of the first cone spring 77 and the outer peripheral edge of the second cone spring 78. A wire ring is arranged between the outer peripheral edge of the first cone spring 77 and the snap ring 80. As described above, the first cone spring 77 can apply a load to the axial transmission side with respect to the structure including the first and second members 81 and 82, and the second cone spring 78 has the first and second It is possible to apply a load on the axial engine side to the structure formed by the two members 81 and 82. When the clutch is engaged, the cone springs 77 and 78 hardly apply a load to the arm member 76, but during the clutch release operation, a load is applied to the arm member 76 toward the axial transmission side to reduce the release load. That is, the load of the first cone spring 77 is larger than the load of the second cone spring 78.

  The load characteristic of the spring unit 75 is equivalent to the combined load characteristic (FIG. 7) of the cone springs 36 and 37 of the above embodiment, and the structure of the cone spring unit 75 is the same as that of the above embodiment. May be.

  The arm member 76 is a member for connecting the support bolt 73 and the spring unit 75, and the main body 76 a extends along the clutch cover 72. A first engagement portion 76b is formed at one end of the main body portion 76a. The first engaging portion 76b includes a first protruding portion 76e extending from the main body portion 76a toward the axial engine side, and a second protruding portion 76f further extending from the center thereof. The end surface of the first protrusion 76 e is in contact with the axial transmission side surface of the first member 81, and the second protrusion 76 f enters the inside of the first member 81. A second engagement portion 76c is formed at the other end of the main body portion 76a. The second engaging portion 76c is formed with a hole 76d extending in the axial direction, and the body portion 73a of the support bolt 73 is frictionally engaged with the hole 76d. The frictional engagement here means a fixed state until a predetermined load is applied, but slipping occurs when a load greater than the predetermined load is applied. The second engaging portion 76 c extends toward the axial engine side, and the tip end surface is in contact with a portion around the hole 72 a of the clutch cover 72.

  When the clutch release operation is performed from the state shown in FIG. 10, the support bolt 73 and the arm member 76 move to the axial transmission side. At this time, the load acting on the arm member 76 from the spring unit 75 gradually increases. From the above, low release load characteristics can be obtained. At this time, the load from the spring unit 75 acts on the friction engagement portion between the support bolt 73 and the hole 76d, but no slip occurs between the support bolt 73 and the hole 76d. The reason is that the hole 76d is inclined with respect to the bolt 73 by the load of the spring unit 75, and a force that prevents the axial movement is applied to both ends of the hole 76d. When the length of the arm portion 76a is sufficiently long with respect to the axial length of the hole 76d, the lock load exceeds the load of the spring unit 75, so that slippage can be prevented (so-called self-locking). phenomenon). .

  When the friction member wears in the clutch engaged state, the support bolt 73 moves to the friction member side together with the pressure plate. At this time, slip occurs between the support bolt 73 and the hole 76d. Therefore, the postures of the cone springs 77 and 78 in the spring unit 75 do not change. That is, the load characteristic of the second low release load characteristic realizing mechanism 71 does not change due to wear of the friction member.

  As described above, in the friction engagement portion composed of the support bolt 73 and the arm member 76, the resistance acting on the support bolt 73 when the clutch is engaged is made smaller than the resistance acting on the support bolt 73 when the clutch is released. Therefore, it is possible to prevent the pressing load on the pressure plate 3 from being reduced while maintaining the function of the second low release load characteristic realizing mechanism 71.

  The above embodiment is merely an example of the present invention, and various modifications can be made without departing from the spirit of the present invention. For example, the above embodiment is a pull type clutch cover assembly, but the present invention can also be applied to a push type clutch cover assembly.

  The specific structure of the first low release load characteristic realization mechanism and the second low release load characteristic realization mechanism can be changed, and in particular, the first low release load characteristic realization mechanism is a conventional one-piece cone spring structure. May be.

The longitudinal cross-sectional schematic of the clutch cover assembly which concerns on 1st Embodiment of this invention. The longitudinal cross-sectional schematic of the clutch cover assembly which concerns on 1st Embodiment of this invention. The top view of the clutch cover assembly which concerns on 1st Embodiment of this invention. It is the elements on larger scale of Drawing 2, and is a figure for explaining the 2nd low release load characteristic realization mechanism. The longitudinal cross-sectional schematic of the 2nd unit of a 1st low release load characteristic implementation | achievement mechanism. The figure for demonstrating the pressing load characteristic. The figure for demonstrating the synthetic | combination characteristic of a 2nd low release load characteristic implementation | achievement mechanism. The figure for demonstrating the negative gradient characteristic obtained when a cushioning function is exhibited in a set load characteristic. The figure for demonstrating a release load characteristic. The longitudinal cross-sectional schematic of another implementation example of the 2nd low release load characteristic implementation | achievement mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clutch cover assembly 2 Clutch cover 3 Pressure plate 4 Diaphragm spring 30 2nd low release load characteristic implementation mechanism 31 2nd support bolt (support member)
32 Holder (supporting engagement member)
36 First cone spring (second elastic member)
37 Second cone spring (second elastic member)
39 Adjustment spring (third elastic member)
51 Flywheel 52 Clutch Disc Assembly 53 Friction Member

Claims (10)

A clutch cover assembly for pressing and releasing a friction member with a cushioning function of a clutch disk assembly on an engine flywheel,
A clutch cover fixed to the flywheel;
A pressure plate connected to the clutch cover so as not to rotate relative to the clutch cover and sandwiching the friction member with the flywheel;
A diaphragm spring supported by the clutch cover and biasing the pressure plate toward the flywheel;
A first elastic member that is supported by the clutch cover and generates a load that opposes the urging force of the diaphragm spring, thereby flattening a change in the pressing load to the pressure plate with respect to a displacement amount of the diaphragm spring; ,
In the process in which the displacement amount of the diaphragm spring is increased by the cushioning function of the friction member by generating a load that is supported by the clutch cover and opposes the urging force of the diaphragm spring during the release operation. A second elastic member that reduces the pressing load of
A clutch cover assembly comprising:   2. The clutch cover assembly according to claim 1, wherein the second elastic member increases a load as a release operation proceeds from a clutch engaged state.   The clutch cover assembly according to claim 1 or 2, wherein the second elastic member is configured by combining a plurality of elastic members.   The clutch cover assembly according to any one of claims 1 to 3, wherein the second elastic member is disposed on an axially opposite side of the friction member side of the clutch cover. A support member extending from the pressure plate to the clutch cover side;
The clutch cover assembly according to claim 4 , wherein the second elastic member applies a load to the support member on an axially opposite side to the friction member side.   The clutch cover assembly according to any one of claims 1 to 5, wherein the second elastic member is a cone spring.   The clutch cover assembly according to claim 1, further comprising a wear compensation mechanism for maintaining the posture of the second elastic member with respect to wear of the friction member.   The clutch cover assembly according to claim 7, wherein the wear compensation mechanism has a return mechanism for returning the second elastic member to a posture before wear when the friction member is worn. The return mechanism includes a support member that extends from the pressure plate toward the clutch cover, and a support member that engages with the support member and receives a load from the second elastic member toward the friction member side in the axial direction. A combination member, a support engagement member that engages with the support member with a screw and receives a load from the second elastic member on the opposite side to the friction member side, and the support engagement member is the friction member and a third elastic member for applying a constant torque to the support and engagement member to rotate in a direction to move to the side axially opposite the clutch cover assembly according to claim 8.   The wear compensation mechanism includes a support member that extends from the pressure plate to the clutch cover side at a position different from the second elastic member, and friction that is frictionally engaged with the support member and applied with a load from the second elastic member. The clutch cover assembly according to claim 7, further comprising an engaging member.

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