Power transmission device

Abstract

The present invention discloses a power transmission device including a flywheel and a damping unit, which strengthens the fixing strength of the flywheel and avoids the enlargement of the device. The device includes: a flywheel (2) having a plurality of fixing holes (5) and a damping unit (20). The damping unit (20) includes an input side plate (21), a hub flange (22), and a pair of coil springs (47). The input side plate (21) and the hub flange (22) have a plurality of assembly holes (26, 43) arranged at positions corresponding to the fixing holes (5) of the flywheel (2). The plurality of assembly holes (26, 43) are arranged in a circumferential direction, and the intervals between adjacent assembly holes are formed as a pair of accommodation spaces (C) larger than other portions. A first window portion (21a) and a first window hole (41a) for accommodating the pair of coil springs (47) are arranged radially outside the accommodation space (C).

Description

Technical Field

[0001] The present invention relates to a power transmission device. Background Art

[0002] For example, in a hybrid vehicle equipped with an engine and an electric motor, in order to prevent excessive torque from being transmitted from the output side to the engine side during engine startup or the like, a damping device (an example of a power transmission device) having a torque limiting function as shown in Patent Document 1 is used.

[0003] The damping device of Patent Document 1 includes a pair of plates, a hub flange, and a damping portion having a plurality of coil springs. Further, a torque limiter is provided on the outer peripheral side of the damping portion, and the plates of the torque limiter are fixed to the flywheel by rivets. In addition, the flywheel is attached to the crankshaft of the engine by a plurality of bolts.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-27122 Summary of the Invention

[0005] As in Patent Document 1, in a damping device to which a flywheel is attached, a plurality of bolts are used to fix the flywheel to the crankshaft. Moreover, holes for passing the plurality of bolts need to be formed in the hub flange or the like of the damping device. In order to fix the flywheel with high strength, it is preferable to attach the plurality of bolts to positions on a circle with a larger radius.

[0006] If the plurality of bolts are attached to positions on a circle with a larger radius in this way, the holes for passing the bolts in the hub flange are formed at positions closer to the outer peripheral side. Therefore, the window holes for accommodating the coil springs formed in the hub flange are also formed at positions closer to the outer peripheral side, increasing the overall size of the device.

[0007] An object of the present invention is to strengthen the fixing strength of a flywheel and avoid an increase in the size of a device in a power transmission device including a flywheel and a damping device.

[0008] (1) The power transmission device according to the present invention includes a flywheel and a damping device. The flywheel has a plurality of fixing holes and is fixed to a member on the drive source side. The damping device is fixed to the flywheel, transmits torque from the flywheel to a member on the output side, and attenuates torque fluctuations. Further, the damping device includes: an input rotating member, an output rotating member capable of relatively rotating with respect to the input rotating member, and a pair of first elastic members that elastically connect the input rotating member and the output rotating member in the rotational direction.

[0009] Furthermore, the input rotating member and the output rotating member have a plurality of assembly holes and a pair of first accommodating portions. The plurality of assembly holes are arranged at positions corresponding to the fixing holes of the flywheel. The pair of first accommodating portions accommodate a pair of first elastic members. In addition, the plurality of assembly holes are arranged in the circumferential direction, and two sets of adjacent assembly holes are arranged at intervals larger than those of the remaining adjacent sets of assembly holes, so as to respectively form accommodating spaces between the two sets of adjacent assembly holes. Moreover, the pair of first accommodating portions are arranged radially outside the accommodating spaces.

[0010] In this power transmission device, a fixing member such as a bolt passes through the assembly holes of the input rotating member and the output rotating member and is inserted into the fixing hole of the flywheel, whereby the flywheel and the damping device are fixed to a member on the driving source side such as a crankshaft.

[0011] Here, the plurality of assembly holes are arranged in the circumferential direction and at non-uniform intervals, and accommodating spaces are formed in a part thereof. Moreover, since the first accommodating portion of the output rotating member is arranged radially outside the accommodating space, even if the assembly holes are formed at positions on a circle with a larger radius defined by the installation position of the bolt, the first accommodating portion can be arranged relatively closer to the radially inner side. Therefore, the fixing strength of the flywheel can be enhanced, and the enlargement of the device can be avoided.

[0012] (2) Preferably, each of the plurality of assembly holes has a plurality of first assembly holes and a plurality of second assembly holes arranged in the circumferential direction at a first interval, and the adjacent first assembly holes and second assembly holes are arranged at a second interval larger than the first interval. Moreover, the accommodating space is formed between the first assembly hole and the second assembly hole arranged at the second interval.

[0013] (3) Preferably, the damping device further has a pair of second elastic members that elastically connect the input rotating member and the output rotating member in the rotational direction, and the input rotating member and the output rotating member further have a pair of second accommodating portions. The second accommodating portions are arranged radially outside the first assembly holes and the second assembly holes and accommodate the second elastic members.

[0014] (4) Preferably, the output rotating member is configured such that one of the pair of second accommodating portions communicates with at least one of the first assembly holes and the second assembly holes, and the other of the pair of second accommodating portions communicates with at least one of the other of the first assembly holes and the second assembly holes.

[0015] Here, the output rotating member is configured such that one of the pair of second receiving portions communicates with at least one of the plurality of first assembly holes and one of the second assembly holes, and the other of the pair of second receiving portions communicates with at least one of the plurality of first assembly holes and the other of the second assembly holes. Therefore, even when the second receiving portion is provided, an increase in the size of the device can be avoided.

[0016] (5) Preferably, the plurality of assembly holes can be penetrated by a fixing member for fixing the flywheel to a member of the drive source.

[0017] (6) Preferably, the input rotating member has a first plate and a second plate that are arranged at intervals in the axial direction and fixed to each other. In addition, the output rotating member has a hub connected to a member on the output side and a flange that extends radially outward from the outer peripheral portion of the hub and is disposed between the first plate and the second plate. In this case, the plurality of assembly holes are formed in the first plate, the second plate, and the flange.

[0018] (7) Preferably, the damping device further has a torque limiting unit fixed to the outer peripheral portion of the input rotating member. The torque limiting unit fixes the outer peripheral portion to the flywheel and transmits torque within a preset range.

[0019] (8) Preferably, the torque limiting unit has a cover member fixed to the flywheel, a friction member fixed to the input rotating member, a pressing member that presses the friction member against the cover member, and a release mechanism for releasing the pressing force of the pressing member with respect to the friction member.

[0020] When the torque limiting unit operates, the flywheel rotates relative to the damping device. In this case, the rotational phases of the fixing hole of the flywheel and the assembly hole of the damping device are misaligned, and a fixing member such as a bolt installed on the flywheel cannot be removed.

[0021] Therefore, a release mechanism is provided to release the pressing force of the pressing member of the torque limiting unit. By using the release mechanism to release the pressing force of the pressing member, the flywheel can rotate freely relative to the damping device. Therefore, it becomes easier to align the fixing hole of the flywheel and the assembly hole of the damping device, and the flywheel and the damping device can be removed from the crankshaft or the like.

[0022] (9) Preferably, the release mechanism has a threaded hole formed in the cover member and a threaded member. The threaded member releases the pressing force of the pressing member by being screwed into the threaded hole.

[0023] In the present invention as described above, in a power transmission device including a flywheel and a damping device, the fixing strength of the flywheel can be enhanced, and an increase in the size of the device can be avoided. Description of the Drawings

[0024] Figure 1A cross-sectional view of a damping device with a torque limiter according to an embodiment of the present invention.

[0025] Figure 2 is Figure 1 a front view of the damping device.

[0026] Figure 3 is a front view of the second plate.

[0027] Figure 4 is a front view of the hub flange.

[0028] Description of Reference Numerals

[0029] 2... Flywheel; 5... Fixing hole; 10... Torque limiting unit; 11... Damping cover (cover member); 11a... Threaded hole for pressure release; 12... Friction plate (friction member); 13... Pressure plate; 14... Conical spring (pressing member); 20... Damping unit; 21... Input side plate (input rotating member); 211... First plate; 212... Second plate; 21a... First window portion (first accommodating portion); 21b... Second window portion (second accommodating portion); 22... Hub flange (output rotating member); 26, 43... Assembly holes; 261, 431... First assembly holes; 262, 432... Second assembly holes; 27... Bolt (fixing member); 30... Hub; 40... Flange; 41a... First window hole (first accommodating portion); 41b... Second window hole (second accommodating portion); 47... Helical spring (first elastic member); 48... Resin member (second elastic member); 70... Bolt for pressure release; C... Accommodating space. Detailed Description of the Embodiment

[0030] [Overall Structure]

[0031] Figure 1 A cross-sectional view of a damping device 1 with a torque limiter according to an embodiment of the present invention (an example of a power transmission device, hereinafter, only referred to as "damping device 1"). In addition, Figure 2 is a front view of the damping device 1, with some members removed or a part of a member deleted and shown. In Figure 1 , the O-O line is the rotation axis. In Figure 1 , an engine is arranged on the left side of the damping device 1, and a drive unit including a motor, a speed change device, etc. is arranged on the right side.

[0032] In addition, in the following description, the axial direction is the direction in which the rotation axis O of the damping device 1 extends. Further, 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 a circle centered on the rotation axis O. In addition, the circumferential direction does not need to be exactly the same as the circumferential direction of the circle centered on the rotation axis O. For example, it also includes the concept of the left-right direction based on the window portion and the window hole shown in Figure 2 In addition, the radial direction does not need to be exactly the same as the diameter direction of the circle centered on the rotation axis O. For example, it also includes the concept of the up-down direction based on the window portion and the window hole shown in Figure 2 .

[0033] The damping device 1 is provided between the crankshaft (an example of a member on the drive source side) of an engine (not shown) and the input shaft of the drive unit, and is a device that restricts the torque transmitted between the engine and the drive unit and attenuates rotational fluctuations at the same time. The damping device 1 includes a flywheel 2, a torque limiting unit 10, and a damping unit 20.

[0034] [Flywheel 2]

[0035] The flywheel 2 includes a drive plate 3 disposed on the engine side and an inertial member 4.

[0036] The drive plate 3 is formed in a disc shape, has six fixing holes 5 in its inner peripheral portion, and has a plurality of rivet holes 6 in its outer peripheral portion. The six fixing holes 5 are arranged on a circumference with a certain radius defined according to the mounting positions of the bolts, and are three first fixing holes 5a and second fixing holes 5b, respectively. In addition, the fixing holes 5 of the flywheel 2 are arranged at the same positions as the assembly holes 26 and 43 of the input side plate 21 and the hub flange 22 described later. Therefore, details will be described later.

[0037] The inertial member 4 is formed in a ring shape and is fixed to the outer peripheral portion of the drive plate 3 on the side opposite to the engine.

[0038] [Torque Limiting Unit 10]

[0039] The torque limiting unit 10 is disposed on the outer peripheral side of the damping unit 20. The torque limiting unit 10 restricts the torque transmitted between the flywheel 2 and the damping unit 20. The torque limiting unit 10 includes a damping cover 11 (an example of a cover member), a friction plate 12 (an example of a friction member), a pressure plate 13, and a conical spring 14 (an example of a pressing member).

[0040] The damper cover 11 is fixed to the drive plate 3 together with the inertia member 4 by a plurality of rivets 15. The pressure plate 13 is arranged with the friction plate 12 interposed therebetween and the damper cover 11. The conical spring 14 is arranged between the pressure plate 13 and the inertia member 4, and the outer peripheral end portion thereof is supported by the inner peripheral end portion of the inertia member 4, and the inner peripheral end portion presses the pressure plate 13. That is, the conical spring 14 presses the friction plate 12 against the damper cover 11 via the pressure plate 13.

[0041] Here, as Figure 1 and Figure 2 shown, a plurality of threaded holes 11a for releasing the pressing force are formed in the damper cover 11. The threaded holes 11a penetrate in the axial direction. The threaded holes 11a are formed at positions radially outward of the outer peripheral surface of the friction plate 12. In addition, the pressure plate 13 has substantially the same outer diameter as the friction plate 12. Moreover, a plurality of protrusions 13a protruding further radially outward from the outer peripheral surface are formed on the outer peripheral surface of the pressure plate 13. The protrusions 13a are formed at the same positions as the threaded holes 11a of the damper cover 11 in the radial direction and the circumferential direction.

[0042] In addition, as Figure 1 shown, a plurality of protrusions are formed at the outer peripheral end portion of the pressure plate 13, and the protrusions are bent toward the damper cover 11 and function as a plurality of engaging portions 13b. The engaging portions 13b are inserted into the holes 11b formed in the damper cover 11. Therefore, the pressure plate 13 cannot rotate relative to the damper cover 11.

[0043] [Damper unit 20]

[0044] The damper unit 20 is composed of an input side plate 21 (an example of an input rotating member), a hub flange 22 (an example of an output rotating member), and a damping portion 23 disposed between the input side plate 21 and the hub flange 22.

[0045] <Input side plate 21>

[0046] The input side plate 21 has a first plate 211 and a second plate 212 (hereinafter, the first plate 211 and the second plate 212 may also be collectively referred to as "input side plate 21"). As Figure 3 shown, both the first plate 211 and the second plate 212 are annular members having a central hole. In addition, Figure 3 only the second plate 212 is shown, but the basic structure of the first plate 211 is the same. The first plate 211 and the second plate 212 are fixed to each other by four stop pins 24 (refer to Figure 2 ) at a predetermined interval in the axial direction. Therefore, the first plate 211 and the second plate 212 cannot move relative to each other in the axial direction and the rotational direction. In addition, as Figure 1 shown, the inner peripheral portion of the friction plate 12 is fixed to the outer peripheral portion of the first plate 211 by a plurality of rivets 25.

[0047] As shown Figure 3 in FIGS. 2 and 3, a pair of first window portions 21a (an example of a first housing portion) and second window portions 21b (an example of a second housing portion) are respectively formed in a first plate 211 and a second plate 212. The pair of first window portions 21a are disposed opposite to each other with the rotation axis O therebetween. Figure 3 FIG. 3 shows the first window portion 21a and the second window portion 21b of the second plate 212, but the first window portion and the second window portion of the first plate 211 have the same structure. The pair of first window portions 21a are formed by partially cutting the respective plates 211 and 212, and have pressing surfaces 21c at both end faces in the circumferential direction, and support portions at the outer periphery and the inner periphery respectively. In addition, the pair of second window portions 21b are disposed opposite to each other with the rotation axis O therebetween at an interval of 90°. The pair of second window portions 21b are arc-shaped openings extending in the circumferential direction and penetrating in the axial direction, and have pressing surfaces 21d at both end faces in the circumferential direction.

[0048] Four rivet holes 21e and six assembly holes 26 are formed in the first plate 211 and the second plate 212. The rivet holes 21e are holes for riveting rivets 25, and are formed at positions corresponding to the rivets 25. The six assembly holes 26 are holes for fixing the flywheel 2 to the crankshaft, and have a size that allows bolts 27 (see Figure 1 and Figure 2 ) to penetrate therethrough. The arrangement of the assembly holes 26 will be described later.

[0049] <Hub flange 22>

[0050] The hub flange 22 is a member for transmitting the torque from the input side plate 21 to the output side device. As shown in FIGS. 4 and 5, the hub flange 22 has a hub 30 and a flange 40. Figure 1 and Figure 2 FIGS. 4 and 5 show that the hub 30 is formed in a cylindrical shape and extends in the central holes of the first plate 211 and the second plate 212. A spline hole is formed in the inner peripheral portion of the hub 30, and an output side member can be spline-engaged with the spline hole.

[0051] As shown in FIGS. 6 and 7, the flange 40 is formed in a disk shape extending radially outward from the outer peripheral surface of the hub 30, and is disposed between the first plate 211 and the second plate 212 in the axial direction. The flange 40 has a pair of first window holes 41a (an example of a first housing portion) and second window holes 41b (an example of a second housing portion), a pair of first locking holes 42a and second locking holes 42b, and six assembly holes 43 for assembling bolts 27.

[0052] As shown Figure 2 and Figure 4 in FIGS. 6 and 7, the flange 40 is formed in a disk shape extending radially outward from the outer peripheral surface of the hub 30, and is disposed between the first plate 211 and the second plate 212 in the axial direction. The flange 40 has a pair of first window holes 41a (an example of a first housing portion) and second window holes 41b (an example of a second housing portion), a pair of first locking holes 42a and second locking holes 42b, and six assembly holes 43 for assembling bolts 27.

[0053] The first window hole 41a is disposed opposite across the rotation axis O, and is formed at a position corresponding to the first window portion 21a of the first plate 211 and the second plate 212. The first window hole 41a has pressing surfaces 41c at both end surfaces in the circumferential direction. Moreover, the pressing surface 41c on the R1 side (hereinafter, only referred to as the "R1 side") in the circumferential direction of the first window hole 41a has a protruding portion 41d, and the protruding portion 41d protrudes in a manner of bulging toward the opposing pressing surface 41c (i.e., in the circumferential direction).

[0054] The second window hole 41b is disposed opposite across the rotation axis O at an interval of 90° from the first window hole 41a. That is, the second window hole 41b is formed at a position corresponding to the second window portion 21b of the first plate 211 and the second plate 212. The second window hole 41b is formed in a rectangular shape, and the radial position (the central position of the width in the radial direction of the hole) of the second window hole 41b is located at a position closer to the inner side in the radial direction than the radial center position of the first window hole 41a. The second window hole 41b has pressing surfaces 41f at both end surfaces in the circumferential direction, and the distance between the two pressing surfaces 41f is set shorter than the distance (the length in the circumferential direction) between the two pressing surfaces 21d of the second window portion 21b of the input side plate 21.

[0055] As Figure 4 shown, the first locking hole 42a is an elongated hole extending in an arc shape on the R1 side of the first window hole 41a. The first locking hole 42a is formed separately from the first window hole 41a. The end portion of the first locking hole 42a away from the first window hole 41a extends to the outside in the radial direction of the second window hole 41b. In addition, the end portion of the first locking hole 42a close to the first window hole 41a extends toward the protruding portion 41d of the first window hole 41a.

[0056] The second locking hole 42b is an elongated hole extending in an arc shape on the R2 side (hereinafter, only referred to as the "R2 side") in the circumferential direction of the first window hole 41a. The end portion on the R1 side of the second locking hole 42b communicates with the central portion in the radial direction of the first window hole 41a.

[0057] In addition, in the first locking hole 42a and the second locking hole 42b, notches 42c bulging outward in the circumferential direction are formed near the end portions on the R2 side. The notches 42c are formed at positions corresponding to the rivet holes 21e of the input side plate 21 so as to have the same size. The rivet 25 can be riveted through the notches 42c and the rivet holes 21e.

[0058] In addition, a detent pin 24 axially penetrates through the first detent hole 42a and the second detent hole 42b. Therefore, the input side plate 21 and the hub flange 22 can rotate relative to each other within the range where the detent pin 24 can move within the respective detent holes 42a and 42b. In other words, a detent mechanism is constituted by the detent pin 24 and the respective detent holes 42a and 42b, and the relative rotation between the input side plate 21 and the hub flange 22 is prohibited by the end surfaces of the detent pin 24 and the respective detent holes 42a and 42b coming into contact with each other.

[0059] Here, the radial positions of the pair of first window holes 41a are the same, but the pitch circle radius P1 of the first detent hole 42a (the radius of the radial center portion of the first detent hole 42a) is larger than the pitch circle radius P2 of the second detent hole 42b. That is, the first detent hole 42a and the second detent hole 42b are formed at radially offset positions.

[0060] Therefore, the end portion on the R2 side of the first detent hole 42a can be made to extend toward the radial center portion (i.e., the protruding portion 41d) of the first window hole 41a. In addition, the end portion on the R1 side of the second detent hole 42b can be made to communicate with the radial center portion of the first window hole 41a.

[0061] [Arrangement of fixing holes 5, assembling holes 26, 43]

[0062] Refer to Figure 3 and Figure 4 The arrangement of the fixing hole 5 and the assembling holes 26 and 43 will be described. In addition, although the fixing hole 5 is not shown in these figures, it is formed at the same position as the assembling holes 26 and 43.

[0063] The six assembling holes 26 and 43 are arranged on a circumference with the same radius, and are respectively three first assembling holes 261 and 431 and three second assembling holes 262 and 432. The three first assembling holes 261 and 431 and the three second assembling holes 262 and 432 are arranged to face each other across the rotation axis O. In addition, the three first assembling holes 261 and 431 and the three second assembling holes 262 and 432 are respectively arranged at a first interval G1. Moreover, the adjacent first assembling holes 261 and 431 and the second assembling holes 262 and 432 are arranged at a second interval G2 that is larger than the first interval G1.

[0064] That is, among the six assembling holes 26 and 43, two sets of adjacent first assembling holes 261 and 431 and second assembling holes 262 and 432 are arranged at an interval wider than that of the other adjacent assembling holes, and a pair of receiving spaces C (at the second interval G2) are respectively formed between the two sets of adjacent assembling holes (each group). The pair of receiving spaces C are formed at positions facing each other across the rotation axis O. Moreover, the first window hole 41a is formed radially outside the receiving space C.

[0065] In addition, in the flange 40 of the hub flange 22, the first assembly hole 431 located in the middle in the circumferential direction among the three first assembly holes 431 is formed radially inward of the second window hole 41b. Moreover, the outer peripheral portion of the first assembly hole 431 communicates with the second window hole 41b. The same applies to the second assembly hole 432, and the outer peripheral portion of one of the three second assembly holes 432 communicates with the second window hole 41b.

[0066] <Damping portion 23>

[0067] The damping portion 23 is a mechanism for elastically connecting the input side plate 21 and the hub flange 22 in the rotational direction. As Figure 1 and Figure 2 shown, it has a pair of coil springs 47 (an example of a first elastic member), a pair of resin members 48 (an example of a second elastic member), and a hysteresis generating mechanism 50.

[0068] The coil spring 47 is housed in the first window hole 41a of the flange 40, and the resin member 48 is housed in the second window hole 41b of the flange 40. In addition, the coil spring 47 and the resin member 48 are supported axially and radially by the respective window portions 21a, 21b of the first plate 211 and the second plate 212.

[0069] In addition, as Figure 2 shown, the resin member 48 is arranged with a gap in the circumferential direction with respect to the second window portion 21b of the input side plate 21. On the other hand, the resin member 48 is arranged without a gap in the circumferential direction with respect to the second window hole 41b of the flange 40.

[0070] A first spring piece 61 is provided on the end face on the R1 side of the coil spring 47, and a second spring piece 62 is provided on the end face on the R2 side. The first spring piece 61 and the second spring piece 62 support the end faces of the coil spring 47 and are supported by the pressing surface 21c of the input side plate 21 and the pressing surface 41c of the hub flange 22. A concave portion that is recessed in an arc shape toward the coil spring 47 side is formed in the first spring piece 61, and a hole that penetrates in the circumferential direction is formed in the central portion of the concave portion. Moreover, the protruding portion 41d of the first window hole 41a of the flange 40 is fitted into the concave portion.

[0071] [Assembly of torque limiting unit 10 and damping unit 20]

[0072] When assembling this damping device 1, first, the torque limiting unit 10 and the damping unit 20 are separately assembled. After that, the inner peripheral portion of the friction plate 12 of the torque limiting unit 10 and the outer peripheral portion of the first plate 211 are riveted and fixed by the rivet 25.

[0073] At this time, a rivet hole 21e is formed in the first plate 211, and a notch 42c for a rivet is formed in the flange 40. Therefore, by using these hole 21e and notch 42c, a riveting tool can be brought into contact with the rivet 25 to rivet the rivet 25.

[0074] [Assembly of the damper device 1 to the crankshaft]

[0075] The torque limiting unit 10 and the damper unit 20 assembled as described above are fixed to the flywheel 2 by the rivet 15. Moreover, when the entire damper device 1 is fixed to the crankshaft, six bolts 27 are respectively inserted into the fixing holes 5 of the flywheel 2 through the assembly holes 26 and 43 of the second plate 212, the hub flange 22, and the first plate 211, and are installed in the threaded holes of the crankshaft. Thus, the damper device 1 can be fixed to the crankshaft of the engine.

[0076] [Operation]

[0077] The torque transmitted from the engine to the flywheel 2 is input to the damper unit 20 via the torque limiting unit 10. In the damper unit 20, torque is input to the input side plate 21 to which the friction plate 12 is fixed in the torque limiting unit 10, and this torque is transmitted to the hub flange 22 via the coil spring 47 and the resin member 48. Moreover, power is transmitted from the hub flange 22 to motors, generators, transmissions, etc. on the output side.

[0078] In addition, for example, when the engine starts, the inertia on the output side is large, so there is a case where excessive torque is transmitted from the output side to the engine. In such a case, the torque transmitted to the engine side is limited to a specified value or less by the torque limiting unit 10.

[0079] [Removal of the damper device 1 from the crankshaft]

[0080] If the torque limiting unit 10 operates during the above operation, the flywheel 2 and the damper unit 20 rotate relative to each other. In this case, the rotational phases of the fixing holes 5 of the flywheel 2 and the assembly holes 26 and 43 of the damper unit 20 are offset. Therefore, even if a tool is inserted through the assembly holes 26 and 43 of the damper unit 20, the bolts 27 installed in the flywheel 2 cannot be removed.

[0081] Here, to release the pressing force of the conical spring 14 of the torque limiting unit 10, the release bolt 70 is screwed into the threaded hole 11a for releasing the pressing force of the damping cover 11. When the release bolt 70 is screwed in, the front end of the bolt abuts against the protrusion 13a of the pressure plate 13, and the pressure plate 13 is pressed toward the engine side. Here, since the damping cover 11 and the pressure plate 13 cannot rotate relative to each other, the rotational phases of the threaded hole 11a and the protrusion 13a do not shift. Thus, the pressing force of the conical spring 14 that presses the friction plate 12 via the pressure plate 13 is released. When the pressing force of the conical spring 14 is released, the damping unit 20 can rotate freely relative to the flywheel 2 and the damping cover 11.

[0082] In such a state, when the damping unit 20 is rotated, it becomes easier for the assembly holes 26, 43 of the damping unit 20 to align with the fixing holes 5 of the flywheel 2. Further, by inserting a tool through the assembly holes 26, 43 and removing the bolts 27, the damping device 1 can be removed from the crankshaft.

[0083] [Other Embodiments]

[0084] The present invention is not limited to the above-described embodiments, and various modifications or corrections can be made without departing from the scope of the present invention.

[0085] (a) The structures of the torque limiting unit 10 and the damping unit 20 are not limited to the above-described embodiments. Further, the present invention can also be applied to a damping device that does not have the torque limiting unit 10.

[0086] (b) The numbers of the fixing holes 5 of the flywheel 2 and the assembly holes 26, 43 of the damping unit 20 are not limited to the above-described embodiments.

[0087] (c) In the above-described embodiment, the resin member 48 is provided in the damping portion 23, but the damping portion may have only the coil spring 47.

[0088] (d) In the above-described embodiment, in the input side plate 21, the assembly hole 26 does not communicate with the second window portion 21b, but the assembly holes 261, 262 radially inward of the second window portion 21b may communicate with the second window portion 21b.

Claims

1. A power transmission device, characterized in that, it comprises: a flywheel having a plurality of fixing holes and fixed to a member on the driving source side; and a damping device fixed to the flywheel, transmitting the torque from the flywheel to a member on the output side and attenuating torque fluctuations, the damping device having: an input rotating member; an output rotating member capable of rotating relative to the input rotating member; and a pair of first elastic members elastically connecting the input rotating member and the output rotating member in the rotational direction, the input rotating member and the output rotating member having: a plurality of assembling holes arranged at positions corresponding to the fixing holes of the flywheel; and a pair of first accommodating portions for accommodating the pair of first elastic members, the plurality of assembling holes are arranged in the circumferential direction of a circle centered on the rotation axis of the damping device, and two adjacent sets of assembling holes are arranged at an interval larger than that of each of the remaining adjacent sets of assembling holes, thereby respectively forming accommodating spaces between the two adjacent sets of assembling holes, the pair of first accommodating portions are arranged opposite to each other across the rotation axis, the pair of first accommodating portions are arranged radially outside the accommodating spaces formed at positions opposite to each other across the rotation axis.

2. The power transmission device according to claim 1, characterized in that, each of the plurality of assembling holes has a plurality of first assembling holes and a plurality of second assembling holes arranged at a first interval in the circumferential direction, and the adjacent first assembling holes and second assembling holes are arranged at a second interval larger than the first interval, the accommodating space is formed between the first assembling hole and the second assembling hole arranged at the second interval.

3. The power transmission device according to claim 1 or 2, characterized in that, the damping device further has a pair of second elastic members elastically connecting the input rotating member and the output rotating member in the rotational direction, the input rotating member and the output rotating member further have a pair of second accommodating portions, and the second accommodating portions are arranged radially outside the first assembling holes and the second assembling holes and accommodate the second elastic members.

4. The power transmission device according to claim 3, characterized in that, the output rotating member is configured such that one of the pair of second accommodating portions communicates with at least one of the plurality of first assembling holes and the second assembling holes, and the other of the pair of second accommodating portions communicates with at least one of the other of the plurality of first assembling holes and the second assembling holes.

5. The power transmission device according to claim 1 or 2, characterized in that, the plurality of assembling holes can be penetrated by fixing members for fixing the flywheel to the driving source.

6. The power transmission device according to claim 1 or 2, characterized in that, the input rotating member has a first plate and a second plate arranged at an interval in the axial direction and fixed to each other, The output rotating member has a hub connected to the member on the output side, and a flange extending radially outward from the outer peripheral portion of the hub and disposed between the first plate and the second plate. A plurality of the assembly holes are formed in the first plate, the second plate, and the flange.

7. The power transmission device according to claim 1 or 2, characterized in that the damping device further has a torque limiting unit fixed to the outer peripheral portion of the input rotating member, the torque limiting unit fixes the outer peripheral portion to the flywheel and transmits torque within a preset range.

8. The power transmission device according to claim 7, characterized in that the torque limiting unit has: a cover member fixed to the flywheel; a friction member fixed to the input rotating member; a pressing member that presses the friction member against the cover member; and a release mechanism for releasing the pressing force of the pressing member relative to the friction member.

9. The power transmission device according to claim 8, characterized in that the release mechanism has: a threaded hole formed in the cover member; and a threaded member that releases the pressing force of the pressing member by being screwed into the threaded hole.

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