Damping device

Abstract

In a vibration damper, hysteresis torque in a low torsion angle region is reduced and sufficient hysteresis torque is obtained in a high torsion angle region by a simple structure. The vibration damper includes an input side plate (30), a hub flange (40), a coil spring (51), and a hysteresis generation mechanism (60). The hysteresis generation mechanism (60) has a friction member including a first bushing (61) and a friction plate (64) arranged so as to be in frictional contact with the input side plate (30) to generate hysteresis torque. The friction member is not in frictional contact with the input side plate (30) in a low torsion angle region from a neutral state toward the positive side and the negative side. In addition, the friction member is in frictional contact with the input side plate (30) to generate hysteresis torque in a high torsion angle region. Furthermore, the friction member is positioned at a neutral position by the operation of the coil spring (51) in the neutral state.

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration damper. BACKGROUND

[0002] Generally, abnormal noise and vibration of a vehicle exist in abnormal noise at idling, abnormal noise at running, and sudden braking or sudden start (low frequency vibration). A vibration damper is provided in order to suppress these abnormal noise and vibration.

[0003] With respect to the abnormal noise at idling, it is preferable that the torsional rigidity be low in the low torsion angle region of the torsional characteristics of the vibration damper. On the other hand, with respect to the sudden braking or sudden start, it is necessary to make the torsional characteristics as high as possible.

[0004] Here, the vibration damper shown in Patent Document 1 is provided. In the device shown in this Patent Document 1, the torsional rigidity in the low torsion angle region is suppressed to be low and becomes a low hysteresis torque, to suppress the abnormal noise at idling. In addition, the torsional rigidity of the second stage (high torsion angle region) of the torsional characteristics is set to be high, to attenuate the vibration of the sudden braking or sudden start.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-175440

[0006] In the vibration damper shown in the above Patent Document 1, in order to obtain a low hysteresis torque in the low torsion angle region, it is necessary to separate the spline hub, which is a member on the output side, into a cylindrical hub and a flange or the like structure provided on the outer peripheral side of the hub, and the structure of the device is very complicated. SUMMARY

[0007] The present application relates to a vibration damper.

[0008] (1) The vibration damper according to the present application includes a first rotation body and a second rotation body each rotating around a rotation axis, an elastic link, and a hysteresis generation mechanism. The second rotation body is capable of relative rotation with respect to the first rotation body. The elastic link has a first elastic member and a second elastic member, and elastically links the first rotation body and the second rotation body in the rotation direction. The hysteresis generation mechanism has a friction member disposed so as to be capable of frictional contact with at least either of the first rotation body and the second rotation body, and generates a hysteresis torque when the second rotation body is twisted by relative rotation with respect to the first rotation body.

[0009] The friction member of the hysteresis generation mechanism is not in frictional contact with either the first rotating body or the second rotating body in a prescribed torsion angle region on the first side of the rotational direction and the second side of the rotational direction from a neutral state in which there is no torsion between the first rotating body and the second rotating body. In addition, the friction member is in frictional contact with the first rotating body or the second rotating body in a torsion angle region exceeding the prescribed torsion angle region, thereby generating a hysteresis torque. Furthermore, the friction member is positioned in the neutral position in the neutral state by the operation of the first elastic member and the second elastic member.

[0010] Furthermore, the "neutral position" of the friction member is the position of the friction member in the rotational direction in the neutral state in which there is no torsion between the first rotating body and the second rotating body.

[0011] Here, when the first rotating body and the second rotating body are twisted by a prescribed angle from the neutral state in which the torsion angle is 0° toward the first side of the rotational direction and the second side of the rotational direction (i.e., the positive side and the negative side of the torsion characteristic), the friction member is not in frictional contact with either the first rotating body or the second rotating body. Therefore, in this case, no hysteresis torque is generated, and it is possible to reduce the hysteresis torque of the device as a whole in the low torsion angle region. In addition, in a high torsion angle region in which the torsion angle exceeds the prescribed angle, the friction member is in frictional contact with the first rotating body or the second rotating body, thereby generating a hysteresis torque.

[0012] Furthermore, when the first rotating body and the second rotating body return from the twisted state to the neutral state, the friction member is positioned in the neutral position by the operation of the first elastic member and the second elastic member. That is, in the neutral state, the friction member is always maintained in the neutral position.

[0013] As described above, in the neutral state, it is possible to position the friction member in the neutral position always using the elastic member that is always used in the vibration damper. Furthermore, it is possible to make the friction member not operate in the low torsion angle region and operate in the high torsion angle region. Therefore, it is possible to reduce the hysteresis torque in the low torsion angle region by a simple structure without providing a split-type hub flange or the like, and it is possible to obtain a sufficient hysteresis torque in the high torsion angle region.

[0014] (2) Preferably, the first rotating body has a first support portion and a second support portion. In addition, the second rotating body has a first housing portion and a second housing portion. The first housing portion is disposed offset to the first side of the rotational direction in such a manner that a part thereof overlaps the first support portion when viewed in the axial direction. The second housing portion is disposed offset to the second side of the rotational direction in such a manner that a part thereof overlaps the second support portion when viewed in the axial direction. In this case, the first elastic member is disposed in the first support portion and the first housing portion in a pre-compressed state. In addition, the second elastic member is disposed in the second support portion and the second housing portion in a pre-compressed state and operates in parallel with the first elastic member.

[0015] Here, the support portions and the receiving portions are arranged so as to be offset in opposite directions, and the elastic members are arranged so as to be compressed. Therefore, a gap exists in the rotational direction between the elastic members and the friction members, and between the end surfaces of the support portions or the receiving portions in which the elastic members are arranged. Therefore, the friction members do not come into frictional contact with the first rotary body and the second rotary body due to the twist angle corresponding to the gap.

[0016] Furthermore, if the relative rotation of the second rotary body with respect to the first rotary body continues, the gap between the elastic members and the end surfaces of the support portions or the receiving portions disappears, and the rotation of the friction members stops, but the first rotary body or the second rotary body rotates, and therefore the friction members come into frictional contact with the first rotary body or the second rotary body, and a hysteresis torque is generated.

[0017] (3) Preferably, the offset amount of the first support portion and the first receiving portion is the same as the offset amount of the second support portion and the second receiving portion. In this case, when the twist angle of the first rotary body and the second rotary body from the neutral state toward an angle corresponding to the offset amount, the friction members do not come into frictional contact with the first rotary body and the second rotary body. In addition, if the twist angle of the first rotary body and the second rotary body exceeds the angle corresponding to the offset amount, the friction members come into frictional contact with either of the first rotary body and the second rotary body.

[0018] (4) Preferably, the friction member has a first abutting portion and a second abutting portion. The first abutting portion abuts against the end surface on the first side in the rotational direction of the first elastic member. The second abutting portion abuts against the end surface on the second side in the rotational direction of the second elastic member.

[0019] Here, the friction member abuts against one end surface of the first elastic member and the other end surface of the second elastic member. In addition, the first elastic member and the second elastic member are arranged so as to be compressed in opposite directions in advance. Therefore, in the neutral state, the friction member is always positioned at the neutral position by the first elastic member and the second elastic member.

[0020] (5) Preferably, the first elastic member is further compressed from the compressed state via the free state when the first rotary body is twisted from the neutral state to the first side in the rotational direction with respect to the second rotary body, and is further compressed from the compressed state when the first rotary body is twisted from the neutral state to the second side in the rotational direction with respect to the second rotary body.

[0021] Further, in this case, the second elastic member is further compressed from the compressed state via the free state when the first rotary body is twisted from the neutral state to the second side of the rotational direction with respect to the second rotary body, and is further compressed from the compressed state when the first rotary body is twisted from the neutral state to the first side of the rotational direction with respect to the second rotary body.

[0022] Further, the "free state" here is a state in which each elastic member has no compression or elongation of the free length.

[0023] In this vibration damping device, in the neutral state, the first rotary body and the second rotary body are subjected to a torsional torque in either of the first side of the rotational direction and the second side of the rotational direction by the first elastic member and the second elastic member arranged in the compressed state. Therefore, even if a torque variation below the torsional torque generated by the compressed elastic member is input, the first rotary body and the second rotary body do not rotate with respect to each other. Therefore, it is possible to suppress a collision sound between the members due to the torque variation within a prescribed torsional angle range.

[0024] (6) Preferably, the first support portion and the second support portion each have a first support surface at an end portion of the first side of the rotational direction and a second support surface at an end portion of the second side of the rotational direction. Further, the first housing portion and the second housing portion have a first housing surface at an end portion of the first side of the rotational direction and a second housing surface at an end portion of the second side of the rotational direction. In this case, the first elastic member is arranged in compression between the first support surface and the second housing surface, and the second elastic member is arranged in compression between the first housing surface and the second support surface.

[0025] (7) Preferably, the first elastic member and the second elastic member have the same rigidity.

[0026] (8) Preferably, the elastic link portion further has a third elastic member and a fourth elastic member. The third elastic member and the fourth elastic member are arranged in advance in compression in the neutral state. Further, the third elastic member is further compressed from the compressed state via the free state when the first rotary body is twisted from the neutral state to the first side of the rotational direction with respect to the second rotary body. The fourth elastic member is further compressed from the compressed state via the free state when the first rotary body is twisted from the neutral state to the second side of the rotational direction with respect to the second rotary body.

[0027] (9) Preferably, the first rotary body has a third support portion and a fourth support portion. The third support portion is arranged opposite the first support portion across the rotational axis. The fourth support portion is arranged opposite the second support portion across the rotational axis. Further, the second rotary body has a third housing portion and a fourth housing portion. The third housing portion is arranged opposite the first housing portion across the rotational axis. The fourth housing portion is arranged opposite the second housing portion across the rotational axis.

[0028] In this case, the third housing portion is arranged so as to be offset to the first side in the rotation direction with a part overlapping the third support portion when viewed in the axial direction. In addition, the fourth housing portion is arranged so as to be offset to the second side in the rotation direction with a part overlapping the fourth support portion when viewed in the axial direction. Furthermore, the third elastic member is arranged so as to be pre-compressed between the third support portion and the third housing portion. In addition, the fourth elastic member is arranged so as to be pre-compressed between the fourth support portion and the fourth housing portion, and works in parallel with the third elastic member.

[0029] In the present application as described above, in the vibration damping device, it is possible to make the hysteresis torque in the low torsion angle region small with a simple structure, and to obtain sufficient hysteresis torque in the high torsion angle region. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a sectional view of a vibration damping device according to an embodiment of the present application.

[0031] Figure 2 is a front view of the vibration damping device of Figure 1 .

[0032] Figure 3A is a schematic view showing the relationship between the input side plate and the hub flange.

[0033] Figure 3B is a schematic view in the case where the relative rotation angle of the input side plate and the hub flange is θ1.

[0034] Figure 3C is a schematic view in the case where the relative rotation angle of the input side plate and the hub flange is θ2.

[0035] Figure 4 is an enlarged view of the hysteresis generation mechanism.

[0036] Figure 5 is a front view of the hysteresis generation mechanism.

[0037] Figure 6 is a partial enlarged view of Figure 2 .

[0038] Figure 7 is a graph showing the torsion characteristics.

[0039] Figure 8 is an action explanatory view showing the neutral state.

[0040] Figure 9 is an action explanatory view showing the state where the neutral state is changed to a torsion angle of 2°.

[0041] Figure 10is an action explanatory view of a state in which the twist angle is changed from 2° to 4°.

[0042] Figure 11 is an action explanatory view of a state in which the twist angle is changed from 4° to 3°.

[0043] Figure 12 is an action explanatory view of a state in which the twist angle is changed from 3° to 2°.

[0044] Figure 13 is an action explanatory view of a state in which the twist angle is changed from 2° to 1.5°.

[0045] Figure 14 is an action explanatory view of a state in which the twist angle is changed from 1.5° to 1°.

[0046] Figure 15 is an action explanatory view of a state in which the twist angle is changed from 1° to a neutral state. DETAILED DESCRIPTION

[0047] [Overall Structure]

[0048] Figure 1 is a cross-sectional view of a vibration damper 1 with a torque limiter (hereinafter, simply referred to as "vibration damper") according to an embodiment of the present application. In addition, Figure 2 is a front view of the vibration damper 1, a part of which is removed to show the components. Figure 1 In the vibration damper 1, an engine (not shown) is disposed on the left side, and a drive unit (not shown) including a motor, a transmission, and the like is disposed on the right side.

[0049] Further, in the following description, the axial direction is the direction in which the rotation axis O of the vibration damper 1 extends. In addition, the circumferential direction is the circumferential direction of a circle centered on the rotation axis O, and the radial direction is the radial direction of the circle centered on the rotation axis O. Further, the circumferential direction does not need to be completely identical to the circumferential direction of the circle centered on the rotation axis O. In addition, the radial direction does not need to be completely identical to the diameter direction of the circle centered on the rotation axis O.

[0050] The vibration damper 1 is a device provided between a flywheel (not shown) and an input shaft of a drive unit, limits the torque transmitted between an engine and the drive unit, and is used to attenuate rotation variation. The vibration damper 1 has a torque limiter unit 10 and a damper unit 20.

[0051] [Torque Limiter Unit 10]

[0052] The torque limiter unit 10 is disposed on the outer circumferential side of the damper unit 20. The torque limiter unit 10 limits the torque transmitted between the flywheel and the damper unit 20. The torque limiter unit 10 has a cover plate 11, a support plate 12, a friction plate 13, a pressure plate 14, and a conical spring 15.

[0053] The cover plate 11 and the support plate 12 are arranged at a prescribed interval in the axial direction, and the outer peripheral portions of the two plates 11, 12 are fixed to the flywheel by a plurality of bolts 16.

[0054] The friction disc 13, the pressure plate 14, and the coned disc spring 15 are arranged in the axial direction between the cover plate 11 and the support plate 12.

[0055] The friction disc 13 has a core plate and a pair of friction members fixed to both side surfaces of the core plate. Furthermore, the inner peripheral portion of the friction disc 13 is fixed to the damping unit 20 by a plurality of rivets 17. The pressure plate 14 and the coned disc spring 15 are arranged between the friction disc 13 and the support plate 12.

[0056] The pressure plate 14 is formed in a ring shape and is arranged on the support plate 12 side of the friction disc 13. Furthermore, a plurality of claws 14a are formed in the outer peripheral portion of the pressure plate 14, and the claws 14a are engaged with a plurality of engagement holes 12a formed in the support plate 12.

[0057] The coned disc spring 15 is arranged between the pressure plate 14 and the support plate 12. The coned disc spring 15 presses the friction disc 13 toward the cover plate 11 via the pressure plate 14.

[0058] [Damping unit 20]

[0059] The damping unit 20 has an input side plate 30 (one example of a first rotating body), a hub flange 40 (one example of a second rotating body), an elastic link portion 50, and a hysteresis generation mechanism 60.

[0060] < Input side plate 30 >

[0061] The input side plate 30 has a first plate 31 and a second plate 32. The first plate 31 and the second plate 32 are formed in a circular plate shape having a hole in the center portion and are arranged at an interval in the axial direction from each other. The first plate 31 has four stop portions 31a and fixing portions 31b in the outer peripheral portion, respectively. In addition, the first plate 31 and the second plate 32 each have a pair of first support portions 301 and a pair of second support portions 302. In the first plate 31 and the second plate 32, the first support portions 301 and the second support portions 302 are formed at the same position. In addition, a hole 32a for assembly is formed in the first plate 31 at a position corresponding to the rivet 17.

[0062] The stop portion 31a is formed by bending the outer peripheral portion of the first plate 31 toward the second plate 32 side and extends in the axial direction. The fixing portion 31b is formed by bending the front end of the stop portion 31a toward the radial direction outside. This fixing portion 31b is fixed to the outer peripheral end portion of the second plate 32 by a plurality of rivets 33. Therefore, the first plate 31 and the second plate 32 cannot rotate with respect to each other and cannot move in the axial direction from each other.

[0063] A pair of first support portions 301 are disposed opposite each other with the rotation axis O interposed therebetween. In addition, a pair of second support portions 302 are disposed opposite each other with the rotation axis O interposed therebetween at an interval of 90° from the first support portions. Each support portion 301, 302 has a hole that penetrates in the axial direction and a rim portion that is cut out standing up at the inner periphery and the outer periphery of the hole.

[0064] As schematically shown in FIG. 3( Figures 3A-3C ), each support portion 301, 302 has an Rl support surface 301a, 302a at the end portion on the first rotation direction side (hereinafter, simply referred to as "Rl side"), and an R2 support surface 301b, 302b at the end portion on the second rotation direction side (hereinafter, simply referred to as "R2 side"). The width of the hole of each support portion 301, 302 (the distance between the Rl support surface and the R2 support surface) is L.

[0065] Further, in FIG. 3, the first support portion 301 and the second support portion 302 are shown by solid lines, and the first receiving portion 401 and the second receiving portion 402 of the hub flange 40 described later are shown by single-dot chain lines. In addition, FIG. 3 is a schematic view, and differs from the actual specific shape shown in FIG. 1. Figure 2

[0066] <Hub Flange 40>

[0067] As shown in Figure 1 and Figure 2 , the hub flange 40 has a hub 41 and a flange 42 that are formed integrally. The hub flange 40 is relatively rotatable with respect to the input-side plate 30 within a prescribed angular range. The hub 41 is formed in a cylindrical shape, and a spline hole 41a is formed at the center portion thereof. In addition, the hub 41 penetrates the holes of the center portions of the first plate 31 and the second plate 32. The flange 42 is in a circular plate shape, and is formed so as to extend from the outer peripheral surface of the hub 41 to the radially outer side. The flange 42 is disposed between the first plate 31 and the second plate 32 in the axial direction.

[0068] The flange 42 has four stopper protrusions 42b, a pair of first receiving portions 401 and a pair of second receiving portions 402, and four notches 403.

[0069] The four stopper protrusions 42b are formed so as to protrude from the outer peripheral surface of the flange 42 to the radially outer side. The positions at which the stopper protrusions 42b are formed are radially outside the central portions in the circumferential direction of each receiving portion 401, 402. Further, when the input-side plate 30 and the hub flange 40 are relatively rotated with respect to each other, the stopper protrusions 42b come into abutment with the stopper portions 31a of the first plate 31, thereby inhibiting the relative rotation of the input-side plate 30 and the hub flange 40.

[0070] ​As shown in FIG. 3, a pair of first receiving portions 401 is arranged in positions corresponding to the pair of first support portions 301. In addition, a pair of second receiving portions 402 is arranged in positions corresponding to the pair of second support portions 302. In more detail, in a neutral state (torsion angle 0°) in which the relative rotation angle between the input-side plate 30 and the hub flange 40 is 0° and neither of them is twisted, as shown in FIG. 3, the pair of first receiving portions 401 is arranged so as to be offset by an angle θ1 (for example, a torsion angle of 2°) to the R1 side in a manner that a part thereof overlaps the first support portion 301 when viewed in the axial direction. In addition, the second receiving portion 402 is arranged so as to be offset by the same angle θ1 to the R2 side in a manner that a part thereof overlaps the second support portion 302 when viewed in the axial direction. Figure 3A

[0071] Each of the receiving portions 401, 402 is a substantially rectangular hole in which the outer peripheral portion is in a circular arc shape. As shown in FIG. 3, each of the receiving portions 401, 402 has an R1 receiving surface 401a, 402a at the end portion on the R1 side and an R2 receiving surface 401b, 402b at the end portion on the R2 side. The width of the hole of each of the receiving portions 401, 402 (the distance between the R1 receiving surface 401a, 402a and the R2 receiving surface 401b, 402b) is set to be the same as the width of the hole of each of the support portions 301, 302, that is, L. Figure 3A

[0072] Four cutouts 403 are formed from the outer peripheral surface of the flange 42 to the radially inner side at a prescribed depth between the receiving portions 401, 402 adjacent to each other in the circumferential direction. The positions at which the cutouts 403 are formed correspond to the positions of the rivets 17 that link the friction plate 13 of the torque limiting unit 10 and the first plate 31. Thus, the torque limiting unit 10 and the damping unit 20, which are assembled in different processes, respectively, can be fixed by the assembly hole 32a of the second plate 32 and the cutouts 403 of the flange 42 and by the rivets 17.

[0073] < Elastic Linking Portions 50 >

[0074] The elastic linking portions 50 have four coil springs 51 (one example of the first elastic member and the second elastic member) and four resin members 52. Each of the coil springs 51 has an outer spring and an inner spring. The four coil springs 51 are received in each of the receiving portions 401, 402 of the flange 42 and are supported in the radial direction and the axial direction by each of the support portions 301, 302 of the input-side plate 30. These coil springs 51 operate in parallel.

[0075] In addition, the free lengths of the four coil springs 51 are all the same. The free length of the coil spring 51 is the same as the width L of each of the support portions 301, 302 and each of the receiving portions 401, 402. In addition, the rigidity of the four coil springs 51 is the same, and the rigidity of the four resin members 52 is the same.

[0076] ​​<Accommodation state of the coil spring 51>

[0077] Here, the arrangement of the support portions 301, 302 and the accommodation portions 401, 402 in the neutral state and the accommodation state of the coil springs 51 will be described in detail below. Further, in the following description, the first support portion 301 and the first accommodation portion 401 will be sometimes referred to as "first window group w1", and the second support portion 302 and the second accommodation portion 402 will be sometimes referred to as "second window group w2".

[0078] As described above, in the neutral state, as shown in Figure 3A , the pair of first accommodation portions 401 are offset by an angle θ1 to the R1 side with respect to the corresponding first support portion 301. On the other hand, the pair of second accommodation portions 402 are offset by an angle θ1 to the R2 side with respect to the second support portion 302. Further, the coil springs 51 are fitted in a compressed state at openings (holes that pass through in the axial direction) of portions that overlap in the axial direction of the accommodation portions 401, 402 corresponding to the support portions 301, 302.

[0079] Specifically, as shown in Figure 3A , in the neutral state, in the pair of first window groups w1, the end surface on the R1 side of the coil spring 51 is in abutment with the R1 support surface 301a, and the end surface on the R2 side is in abutment with the R2 accommodation surface 401b. On the other hand, in the pair of second window groups w2, the end surface on the R1 side of the coil spring 51 is in abutment with the R1 accommodation surface 402a, and the end surface on the R2 side is in abutment with the R2 support surface 302b.

[0080] <Hysteresis generation mechanism 60>

[0081] As shown in Figure 1 and Figure 4 , the hysteresis generation mechanism 60 has a first bush 61, a second bush 62, a coned spring 63, and a friction plate 64. Further, Figure 4 is an enlarged view of a portion of Figure 1 .

[0082] The first bush 61 is arranged in the axial direction between the first plate 31 and the flange 42. A friction member is fixed to the side of the first bush 61 on the first plate 31. The second bush 62 is arranged in the axial direction between the second plate 32 and the flange 42. A friction member is fixed to the side of the second bush 62 on the flange 42. In addition, a plurality of engagement protrusions 62a (refer to Figure 2The engaging protrusion 62a engages with the engaging hole 32b of the second plate 32. Therefore, the second bushing 62 rotates integrally with the second plate 32. The conical spring 63 is axially positioned between the second bushing 62 and the second plate 32 in a compressed state. The friction plate 64 is axially positioned between the second bushing 62 and the flange 42.

[0083] The first bushing 61, the second bushing 62, and the friction plate 64 are independent components, but they work together as a whole, functioning as friction components of the hysteresis generating mechanism 60. More specifically, the first bushing 61... Figure 4 As shown, it has multiple (two in this example) limiting protrusions 61a and engaging protrusions 61b.

[0084] A limiting protrusion 61a is formed axially on the side of the flange 42 of the first bushing 61. This limiting protrusion 61a is as follows: Figure 5 (A further enlarged view of the main view) shows a long, elongated hole 42c formed in the flange 42 in the circumferential direction. Furthermore, in the neutral state, a gap corresponding to a torsion angle θ1 is formed between the end faces of the limiting protrusion 61a and the elongated hole 42c in the circumferential direction, on both the R1 and R2 sides (the position of the first bushing 61 and the friction plate 64 in this neutral state is referred to as the "neutral position"). Additionally, the engaging protrusion 61b engages with the engaging hole 64a formed in the friction plate 64.

[0085] Therefore, the first bushing 61 and the friction plate 64 cannot rotate relative to each other, but rotate as a whole. In addition, as mentioned above, the second bushing 62 and the second plate 32 rotate as a whole.

[0086] Based on the structure described above, the first bushing 61 and the friction plate 64 are allowed to rotate relative to the flange 42 within a torsion angle of ±θ1. Therefore, there is no frictional contact between the first bushing 61 and the first plate 31, and no hysteresis torque is generated between them. Furthermore, within the torsion angle of ±θ1, the friction plate 64 rotates synchronously with the first plate 31; therefore, there is no frictional contact between the second bushing 62 and the friction plate 64, and no hysteresis torque is generated between them.

[0087] On the other hand, within a range exceeding the torsion angle ±θ1, the first bushing 61 and the friction plate 64 are prohibited from rotating relative to the flange 42. Therefore, frictional contact occurs between the first bushing 61 and the first plate 31, and between the second bushing 62 and the friction plate 64, generating a hysteresis torque between them.

[0088] Here, as Figure 2 And as Figure 2 A magnified view of a part Figure 6As shown, the friction plate 64 is substantially rectangular in shape. Further, on the outer circumferential surface of the friction plate 64, two protrusions 641 projecting to the radially outer side are formed at opposite positions across the rotation axis O. The protrusions 641 are located between the first window group wl and the second window group w2 in the circumferential direction. Moreover, the end surface (one example of the second abutting surface) 641a of each protrusion 641 on the Rl side abuts against the end surface on the R2 side of the coil spring 51 arranged in compression in the second window group w2. Further, the end surface (one example of the first abutting surface) 641b of each protrusion 641 on the R2 side abuts against the end surface on the Rl side of the coil spring 51 arranged in compression in the first window group wl.

[0089] As above, each protrusion 641 of the friction plate 64 is pressed in opposite directions by the pair of coil springs 51 arranged in compression. Therefore, the friction plate 64 and the first bush 61 rotating in synchronization therewith are always positioned at the neutral position in the neutral state.

[0090] [Torsional characteristics: absence of hysteresis torque]

[0091] Here, to easily explain the operation, first, the torsional characteristics based on the four coil springs 51 in the absence of hysteresis torque are described. In Figure 7 , the dashed line indicates the torsional characteristics of the coil springs 51 based on the first window group wl, the double-dot chain line indicates the torsional characteristics of the coil springs 51 based on the second window group w2, and the solid line indicates the torsional characteristics wO after the torsional characteristics are synthesized.

[0092] <First window group wl>

[0093] In the neutral state in which the input-side plate 30 and the hub flange 40 do not rotate relative to each other, as shown in Figure 3A , the coil springs 51 of the first window group wl are arranged in compression between the Rl support surface 301a and the R2 receiving surface 401b. The interval G0 between the Rl support surface 301a and the R2 receiving surface 401b is narrower than the width L (equal to the free length of the coil spring) of each support portion 301, 302 and each receiving portion 401, 402. Therefore, as shown by the dashed line in Figure 7 , in the first window group wl, the torsional torque -t based on the coil springs 51 arranged in compression is generated.

[0094] Figure 3B A state in which the input-side plate 30 and the hub flange 40 are arranged in compression in the first window group wl is shown. In this state, the first support portion 301 and the first receiving portion 401 are arranged in compression.

[0095] Here, in the first window group w1, the gap G1 between the R1 support surface 301a, which is abutted by the R1 side end face of the coil spring 51, and the R2 receiving surface 401b, which is abutted by the R2 side end face of the coil spring 51, is greater than the gap G0. This gap G1 is the same as the free length of the coil spring. That is, when the torsion angle between the input side plate 30 and the hub flange 40 is +θ1, in the first window group w1, the coil spring 51 becomes the free length, as shown... Figure 7 As shown, the torsional torque becomes "0".

[0096] Additionally, if the hub flange 40 twists relative to the input side plate 30 by more than an angle θ1, then as Figure 3C As shown ( Figure 3C The diagram shows the case where the torsion angle is θ2 (>θ1). The end face of the coil spring 51 on the R1 side of the first window group w1 abuts against the R1 receiving surface 401a, and the end face on the R2 side abuts against the R2 supporting surface 301b. Here, the gap G2 between the R1 receiving surface 401a and the R2 supporting surface 301b is narrower than the free length of the coil spring 51. That is, if the torsion angle between the input side plate 30 and the hub flange 40 exceeds θ1, the coil spring 51 is compressed from its free length, such as... Figure 7 As shown, the torsional torque gradually increases.

[0097] On the other hand, when the hub flange 40 twists relative to the input side plate 30 from a neutral state towards the R1 side (the side with negative torsional characteristics), the coil spring 51 of the first window group w1 is always compressed between the R1 support surface 301a and the R2 receiving surface 401b. That is, in the first window group w1, as... Figure 7 As shown, in the torsional region on the negative side, as the torsional angle increases, the torsional torque also increases towards the negative side.

[0098] <Second window group w2>

[0099] In the neutral state, the coil spring 51 of the second window group w2 is compressed between the R1 receiving surface 402a and the R2 support surface 302b. The interval between the R1 receiving surface 402a and the R2 support surface 302b is G0, which is narrower than the width L (equal to the free length of the coil spring) of each support portion 301, 302 and each receiving portion 401, 402. Therefore, as Figure 7 As shown, in the neutral state, in the second window group w2, a torsional torque +t based on the compression of the helical spring 51 is generated.

[0100] When the hub flange 40 twists relative to the input side plate 30 from a neutral state towards the R2 side (positive torsional characteristic), the coil spring 51 of the second window assembly w2 is always compressed between the R1 receiving surface 402a and the R2 supporting surface 302b. That is, in the second window assembly w2, as... Figure 7As shown, in the torsion region on the positive side, the torsional torque increases as the torsion angle increases.

[0101] On the other hand, when the hub flange 40 is twisted by an angle θ1 relative to the input side plate 30 from the neutral state towards the R1 side (negative side), in the second window group w2, the distance between the R1 receiving surface 402a abutted by the end face of the coil spring 51 on the R1 side and the R2 support surface 302b abutted by the end face of the coil spring 51 on the R2 side is greater than the distance G0. This distance is the same as the free length of the coil spring 51. That is, when the twist angle between the input side plate 30 and the hub flange 40 is -θ1, in the second window group w2, as... Figure 7 As shown, the torsional torque is "0".

[0102] Furthermore, if the hub flange 40 twists towards the R1 side relative to the input side plate 30 by more than an angle θ1, then the R1 side end face of the coil spring 51 of the second window assembly w2 abuts against the R1 support surface 302a, and the R2 side end face abuts against the R2 receiving surface 402b. Moreover, if the twist angle further increases, the coil spring 51 compresses from its free length, such as... Figure 7 As shown, the torsional torque gradually increases towards the negative side.

[0103] <Synthetic Torsional Properties>

[0104] As a whole vibration damping unit, the composite Figure 7 The characteristic w1 shown by the dashed line and the characteristic w2 shown by the double-dotted line become the torsional characteristic w0 shown by the solid line. That is, in the neutral state, the torsional torque is "0", and as the torsional angle increases towards the positive and negative sides, the torsional torque also increases towards the positive and negative sides.

[0105] Here, in the overall torsional characteristics of the damping unit, the apparent torsional torque in the neutral state is "0". However, as mentioned above, the components on the input and output sides exert positive and negative torsional torques respectively. Therefore, for the torsional angle range of -θ1 to +θ1, the components on the input and output sides do not rotate relative to each other. Thus, collision noise between components caused by torque variations can be suppressed within this torsional angle range.

[0106] In addition, when the torsion angle exceeds ±θ1, the helical springs 51 of the first window group w1 or the second window group w2 become free length, but compared with the structure in which all helical springs 51 are set to free length, it is able to suppress the collision noise between components.

[0107] [Action: Hysteresis exists]

[0108] Next, use Figure 8and thereafter, the torsional characteristics taking into account the hysteresis torque are explained. In the explanatory diagram, the input side plate 30 is indicated by "IP", and the hub flange 40 is indicated by "HF". In addition, the first bush 61 and the friction plate 64 are explained as "friction member FP". Furthermore, in the explanatory diagram, a case where the input side plate 30 is rotated to the Rl side (positive side in this example) with respect to the hub flange 40 is shown, but the torsional characteristics for the negative side where the rotation is to the opposite side are the same, and therefore, the torsional characteristics for the negative side are omitted here. In addition, in the following explanation, the aforementioned angle θ1 is explained as "2°", but this angle is one example.

[0109] <Neutral state>

[0110] Figure 8 The neutral state is shown. In this neutral state, the coil springs 51 of each window group wl, w2 are in a compressed configuration. In addition, as explained above, the end faces of the protruding portions 641 of the friction plate 64, i.e., the abutting faces 641a, 641b, are in abutment with the end faces of the corresponding coil springs 51, and therefore, are positioned at the neutral position. Therefore, a clearance of 2° is ensured on the Rl side and the R2 side between the restriction protrusion 61a of the first bush 61 and the end face of the long hole 42c of the flange 42.

[0111] <Neutral state -> torsional angle 2°>

[0112] Figure 9 A case where the input side plate IP is twisted 2° to the Rl side with respect to the hub flange HF from the neutral state is shown. Here, the coil springs 51 of the first window group wl are from the compressed elongation to the free length, and the coil springs 51 of the second window group w2 are further compressed from the compressed state of the neutral state.

[0113] In addition, the end faces of the coil springs 51 of each window group wl, w2 are moved to the rotation direction, and therefore, the friction member FP is also rotated. However, in this torsional angle region (neutral -> 2°), the restriction protrusion 61a of the first bush 61 is not in abutment with the end face of the long hole 42c of the flange 42. Therefore, the friction member FP (the first bush 61 and the friction plate 64) is rotated in synchronization with the first plate 31, and no hysteresis torque is generated between the first bush 61 and the input side plate IP (the first plate 31). In addition, the second bush 62 is rotated together with the input side plate IP (the second plate 32), and therefore, no hysteresis torque is generated between the second bush 62 and the friction plate 64.

[0114] <Torsional angle 2° -> 4°>

[0115] Figure 10The case where the input-side plate IP is twisted 4° to the Rl side with respect to the hub flange HF is shown. Here, the coil springs 51 of the first window group w1 are compressed from the free length, and the coil springs 51 of the second window group w2 are further developed in the compression state.

[0116] If the twist angle becomes 2° or more, the restriction protrusion 61a of the first bush 61 abuts against the end surface of the long hole 42c of the flange 42. Therefore, the movement (i.e., rotation) of the friction member FP to the Rl side is prohibited. In this way, if the input-side plate IP is rotated and twisted by an angle of 2° or more with respect to the hub flange HF, the rotation of the friction member FP is prohibited, and therefore, a frictional contact is generated between the first bush 61 and the input-side plate IP (the first plate 31), and a hysteresis torque is generated therebetween. In addition, the second bush 62 rotates together with the input-side plate IP (the second plate 32), and therefore, a hysteresis torque is also generated between the second bush 62 and the friction plate 64.

[0117] < Return to the neutral state: twist angle 4° → 3° >

[0118] Figure 11 The case where the input-side plate IP returns from a state of being twisted 4° or more to the Rl side with respect to the hub flange HF to a twist angle of 3° is shown. In the case of returning to the neutral state, the coil springs 51 of each window group w1, w2 are elongated from the compression state until then, and the compression amount becomes small. In addition, the coil springs 51 of the first window group w1 become the free length if the twist angle is 2°, and are compressed if the twist angle is further reduced.

[0119] Here, in the twist region on the Rl side, the compression amount of the coil springs 51 of the first window group w1 is smaller than that of the second window group w2. In addition, in the region where the twist angle exceeds 2°, a hysteresis torque is generated. Therefore, when returning to the neutral state from a state of a large twist angle, if the twist angle is 3° (one example), the torque based on the coil springs 51 of the first window group w1 and the hysteresis torque based on the hysteresis generation mechanism 60 are balanced with each other. Therefore, the coil springs 51 of the first window group w1 are not further elongated due to the hysteresis torque. That is, if the twist angle is 3° or less when returning to the neutral state, the coil springs 51 of the first window group w1 do not work until a prescribed twist angle, and the twist rigidity of the entire device is only the rigidity (specifically, the rigidity of 1 / 2 of the combined characteristics) of the coil springs 51 of the second window group w2.

[0120] Furthermore, the R1 side end face of the coil spring 51 of the first window group w1, while abutting against the hub flange HF (torsion angle 2°→4°→3°), will not rotate further. Moreover, the abutting surface 641b of the friction plate 64 abuts against the end face of the coil spring 51 of the first window group w1, therefore, the friction member FP will not operate (rotate). On the other hand, the input side plate IP rotates, thus generating a hysteresis torque from the torsion angle 4° to 3°.

[0121] <Return to neutral state: Twist angle 3° → 2°>

[0122] Figure 12 The diagram shows the state where the torsion angle changes from 3° to 2°. In this case, the torque of the helical spring 51 based on the first window group w1 further decreases. Therefore, in this torsion angle region (3°→2°), as described above, the helical spring 51 of the first window group w1 does not operate (elongate), and the overall torsional stiffness of the device is only the stiffness of the helical spring 51 of the second window group w2. Furthermore, in the region where the torsion angle is from 3° to 2°, the friction member FP and the input side plate IP rotate in conjunction with the hysteresis torque, therefore, no hysteresis torque is generated.

[0123] <From a torsion angle of 2° to a neutral state>

[0124] Figure 13 This shows the state where the torsion angle changes from 2° to 1.5°. Figure 12 In the state shown with a torsion angle of 2°, the end face of the coil spring 51 of the first window group w1 on the R2 side abuts against the end faces of the input side plate IP and the hub flange HF on the R2 side. Furthermore, if the torsion angle is smaller than 2°, the end face of the coil spring 51 of the first window group w1 abuts against the end face of the hub flange HF on the R2 side. Therefore, in the region where the torsion angle is smaller than 2°, the friction member FP is repelled by the coil spring 51 of the first window group w1 and cannot rotate in conjunction with the input side plate IP. Thus, a hysteresis torque is generated corresponding to the force (torque) of the coil spring 51 of the first window group w1 being compressed.

[0125] Figure 14 This illustrates the state where the torsion angle changes from 1.5° to 1°. When the torsion angle reaches 1°, the end face of the R1 side of the helical spring 51 of the first window group w1 abuts against the end face of the input side plate IP. Therefore, during the period from the torsion angle from 1° to the neutral state, the helical springs 51 of both the first window group w1 and the second window group w2 operate, resulting in the combined rigidity of the helical springs 51 of both window groups w1 and w2. Additionally, at this moment, the friction member FP (first bushing 61 and friction plate 64) is positioned in the neutral position.

[0126] Figure 15A state in which the twist angle is changed from 1° to the neutral state is shown. Here, the input side plate IP returns to the neutral state together with the friction member FP, and no hysteresis torque is generated therebetween.

[0127] As above, in this embodiment, in a low twist angle region in which the twist angle is small, a small hysteresis torque can be obtained. In addition, in a high twist angle region of a prescribed twist angle or more, a sufficient hysteresis torque can be obtained. In addition, the above characteristics can be achieved by the one-piece hub flange.

[0128] Further, in this embodiment, in the case of the twist characteristic from the neutral state toward the Rl side, no hysteresis torque is generated until the twist angle is 2°, but in the case of the twist angle returning to the neutral state from 2°, a hysteresis torque is generated in a prescribed angle range. However, in the return to the neutral state, in the case of the twist angle oppositely from an angle smaller than 2° toward 2°, no hysteresis torque is generated. Therefore, in the low twist angle region, a small hysteresis torque can be obtained.

[0129] [Other Embodiments]

[0130] The present application is not limited to the above embodiments, and various modifications or changes can be made without departing from the scope of the present application.

[0131] (a) The specific numerical values of the width of each support portion 301, 302 and each housing portion 401, 402, the length of the coil spring 51, or the twist angle are one example, and are not limited to these numerical values.

[0132] (b) In the above embodiment, the rigidity of all the coil springs is made the same, but coil springs of different rigidity can also be used.

[0133] (c) The number of housing portions, support portions, and coil springs is one example, and is not limited to the above embodiment.

[0134] Explanation of Reference Numerals

[0135] 1...damping device; 30...input side plate (first rotating body); 301...first support portion; 302...second support portion; 301a, 302a...R1 support surface; 301b, 302b...R2 support surface; 40...wheel hub flange (second rotating body); 401...first receiving portion; 402...second receiving portion; 401a, 402a...R1 receiving surface; 401b, 402b...R2 receiving surface; 50...elastic link portion; 51...coil spring (first elastic member, second elastic member); 61...first bushing; 62...second bushing; 64...friction plate; 641...protruding portion; 641a, 641b...abutment surface.

Claims

1. A vibration damping device, comprising: The first rotating body rotates about its axis of rotation; A second rotating body, rotating about the rotation axis, and configured to rotate relative to the first rotating body; and An elastic connecting portion, having a first elastic member and a second elastic member, elastically connecting the first rotating body and the second rotating body in the rotational direction; and The hysteresis generating mechanism has a friction member configured to frictionally contact at least one of the first rotating body and the second rotating body, the hysteresis generating mechanism generating a hysteresis torque when the second rotating body rotates relative to the first rotating body and twists. The friction component of the hysteresis generating mechanism Within a defined torsion angle region extending from a neutral state (where there is no torsion between the first and second rotating bodies) towards a first side and a second side of the rotation direction, there is no frictional contact with either the first or second rotating body. In the high torsion angle region exceeding the specified torsion angle region, hysteresis torque is generated through frictional contact with the first rotating body or the second rotating body. In the neutral state, the friction member is positioned in a neutral position through the operation of the first elastic member and the second elastic member. The first rotating body has a first support portion and a second support portion. The second rotating body has: a first receiving portion disposed offset to a first side in the rotational direction such that it partially overlaps with the first support portion when viewed axially; and a second receiving portion disposed offset to a second side in the rotational direction such that it partially overlaps with the second support portion when viewed axially. The first elastic member is pre-compressed and disposed in the first support portion and the first storage portion. The second elastic member is pre-compressed and disposed in the second support portion and the second receiving portion, and operates in parallel with the first elastic member. The offset between the first support portion and the first storage portion is the same as the offset between the second support portion and the second storage portion. The friction component When the torsion angle of the first rotating body and the second rotating body changes from the neutral state to an angle equivalent to the offset, there is no frictional contact with either the first rotating body or the second rotating body. If the torsion angle between the first rotating body and the second rotating body exceeds an angle equivalent to the offset, then frictional contact will occur with either the first rotating body or the second rotating body. The friction member has: a first abutting portion that abuts against an end face of the first elastic member on a first side of the rotation direction; and a second abutting portion that abuts against an end face of the second elastic member on a second side of the rotation direction. When the first rotating body twists relative to the second rotating body from the neutral state to a first side in the rotational direction, the first elastic member is further compressed from a compressed state via a free state, and when the first rotating body twists relative to the second rotating body from the neutral state to a second side in the rotational direction, it is further compressed from a compressed state. The second elastic member is further compressed from a compressed state via a free state when the first rotating body twists relative to the second rotating body from the neutral state to a second side of the rotation direction, and is further compressed from a compressed state when the first rotating body twists relative to the second rotating body from the neutral state to a first side of the rotation direction.

2. The vibration damping device according to claim 1, wherein, The first support portion and the second support portion each have a first support surface at their ends on a first side of the rotation direction and a second support surface at their ends on a second side of the rotation direction. The first storage portion and the second storage portion have a first storage surface at their ends on the first side of the rotation direction, and a second storage surface at their ends on the second side of the rotation direction. The first elastic member is compressed and disposed between the first supporting surface and the second receiving surface. The second elastic member is compressed between the first receiving surface and the second supporting surface.

3. The vibration damping device according to claim 1 or 2, wherein, The first elastic member and the second elastic member have the same rigidity.

4. The vibration damping device according to claim 1 or 2, wherein, The elastic connecting part also has a third elastic member and a fourth elastic member that are pre-compressed in the neutral state. When the first rotating body twists relative to the second rotating body from the neutral state to a first side in the rotational direction, the third elastic member is further compressed from a compressed state via a free state. When the first rotating body twists relative to the second rotating body from the neutral state to the second side of the rotation direction, the fourth elastic member is further compressed from the compressed state via the free state.

5. The vibration damping device according to claim 4, wherein, The first rotating body further comprises: a third support portion disposed opposite to the first support portion across the rotation axis; and a fourth support portion disposed opposite to the second support portion across the rotation axis. The second rotating body further comprises: a third storage portion disposed opposite to the first storage portion across the rotation axis; and a fourth storage portion disposed opposite to the second storage portion across the rotation axis. The third storage section is offset toward the first side of the rotation direction in such a way that it partially overlaps with the third support section when viewed axially. The fourth storage portion is offset toward the second side in the direction of rotation such that it partially overlaps with the fourth support portion when viewed axially. The third elastic member is pre-compressed and disposed in the third support portion and the third storage portion. The fourth elastic member is pre-compressed and disposed in the fourth support portion and the fourth storage portion, and works in parallel with the third elastic member.

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