Power transmission device

Abstract

Suppresses imbalance in the first rotating member. [Solution] The power transmission device comprises a torque limiter and a damper unit. The torque limiter has a first side plate, a second side plate, and a friction plate. The damper unit has a first rotating member, a second rotating member, and an elastic member. The first rotating member is configured to rotate integrally with the friction plate. The second side plate has an annular portion and a cylindrical portion. The annular portion extends in the circumferential direction. The cylindrical portion extends from the outer peripheral end of the annular portion to the first axial side. The first rotating member has an outer peripheral surface that abuts against the inner circumferential surface of the cylindrical portion.

Description

Technical Field

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

Background Art

[0002] The power transmission device disclosed in Patent Document 1 has a torque limiter and a damper unit. The damper unit has a first rotating member, a second rotating member, and an elastic member. The first rotating member is rotatable relative to the second rotating member. The elastic member elastically connects the first rotating member and the second rotating member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When attempting to increase the inertia of the first rotating member, it becomes important to suppress the imbalance of the first rotating member. Therefore, an object of the present invention is to suppress the imbalance of the first rotating member.

Means for Solving the Problems

[0005] The power transmission device according to the first embodiment comprises a torque limiter and a damper unit. The torque limiter has a first side plate, a second side plate, and a friction plate. The second side plate is positioned on the first axial side relative to the first side plate. The second side plate is thinner than the first side plate. The friction plate is positioned between the first and second side plates in the axial direction. The friction plate is positioned to be rotatable relative to the first and second side plates. The damper unit has a first rotating member, a second rotating member, and an elastic member. The first rotating member is configured to rotate integrally with the friction plate. The second rotating member is positioned to be rotatable relative to the first rotating member. The elastic member elastically connects the first rotating member and the second rotating member. The second side plate has an annular portion and a cylindrical portion. The annular portion extends in the circumferential direction. The cylindrical portion extends from the outer peripheral end of the annular portion to the first axial side. The first rotating member has an outer peripheral surface that abuts against the inner circumferential surface of the cylindrical portion.

[0006] With this configuration, the outer surface of the first rotating member is supported by the cylindrical portion of the second side plate, thus suppressing imbalance in the first rotating member.

[0007] The power transmission device according to the second embodiment is configured as follows in the power transmission device according to the first embodiment. The outer circumferential surface of the first rotating member has a contact portion and a non-contact portion. The contact portion extends in an arc shape when viewed in the axial direction. The contact portion contacts the inner circumferential surface of the cylindrical portion. The non-contact portion extends in a straight line when viewed in the axial direction. The non-contact portion does not contact the inner circumferential surface of the cylindrical portion.

[0008] The power transmission device according to the third embodiment is configured as follows in the power transmission device according to the first or second embodiment: The outer edge of the first rotating member is positioned radially outward with respect to the outer edge of the friction plate.

[0009] The power transmission device according to the fourth embodiment is configured as follows in the power transmission device according to any of the first to third embodiments: The torque limiter has a fastening member that fastens the first side plate and the second side plate together. The cylindrical portion is arranged radially outward with respect to the fastening member.

[0010] The power transmission device according to the fifth embodiment is configured as follows in the power transmission device according to any of the first to fourth embodiments: The torque limiter has an inertia member. The inertia member is configured to rotate integrally with the first side plate.

[0011] The power transmission device according to the sixth embodiment is configured as follows in the power transmission device according to the fifth embodiment: The torque limiter has a fastening member that fastens the first side plate and the inertia member. The cylindrical portion is arranged radially outward with respect to the fastening member.

[0012] The power transmission device according to the seventh embodiment is configured as follows in the power transmission device according to the fifth or sixth embodiment: The inertia member has a screw hole extending in the axial direction.

[0013] The power transmission device according to the eighth embodiment is configured as follows in the power transmission device according to any of the fifth to seventh embodiments: The inertia member is annular in shape extending in the circumferential direction. The thickness of the inertia member is greater than the thickness of the first side plate.

[0014] The power transmission device according to the ninth embodiment is configured as follows in the power transmission device according to any of the fifth to seventh embodiments: The inertia member is a nut that is thicker than the thickness of the first side plate.

[0015] The power transmission device according to the tenth embodiment further comprises a drive plate in the power transmission device according to any of the fifth to ninth embodiments. The drive plate is positioned on the second axial side with respect to the first side plate. The first side plate is configured to rotate integrally with the drive plate. The inertia member is positioned axially between the drive plate and the first side plate.

[0016] The power transmission device according to the 11th embodiment is configured as follows in the power transmission device according to any of the first to tenth embodiments: The first side plate has an annular portion and a cylindrical portion. The annular portion of the first side plate extends in the circumferential direction. The cylindrical portion of the first side plate extends from the outer peripheral end of the annular portion to the second axial side. [Effects of the Invention]

[0017] According to the present invention, the imbalance of the first rotating member can be suppressed. [Brief explanation of the drawing]

[0018] [Figure 1] Front view of the power transmission device. [Figure 2] Cross-sectional view along line II-II in Figure 1. [Figure 3] Enlarged cross-sectional view of the power transmission device. [Figure 4] Cross-sectional view of a modified power transmission device. [Modes for carrying out the invention]

[0019] The power transmission device 100 according to this embodiment will be described below with reference to the drawings. In the following description, the axial direction refers to the direction in which the rotation axis O of the power transmission device 100 extends. The circumferential direction refers to the circumferential direction of a circle centered on the rotation axis O, and the radial direction refers to the radial direction of a circle centered on the rotation axis O. The first axial side refers to the right side in Figure 2, and the second axial side refers to the left side in Figure 2.

[0020] FIG. 1 is a front view of the power transmission device 100, and FIG. 2 is a sectional view taken along line II-II of FIG. 1. As shown in FIGS. 1 and 2, the power transmission device 100 includes a drive plate 110, a torque limiter 3, and a damper unit 4. The drive plate 110 and the torque limiter 3 are configured to rotate integrally with each other. The torque limiter 3 and the damper unit 4 are relatively rotatable, but basically rotate integrally with each other. When the torque input to the power transmission device 100 exceeds a predetermined value, the torque limiter 3 and the damper unit 4 rotate relative to each other.

[0021] The power transmission device 100 is provided between a prime mover (not shown) and an output-side member (not shown). The prime mover is, for example, an internal combustion engine. The output-side member is, for example, an electric motor or a transmission. The internal combustion engine is disposed on the second side in the axial direction with respect to the power transmission device 100 (the left side in FIG. 2), and the output-side member is disposed on the first side in the axial direction with respect to the power transmission device 100 (the right side in FIG. 2). The power transmission device 100 is configured to limit the torque transmitted between the internal combustion engine and the output-side member and to attenuate torque fluctuations.

[0022] [Drive Plate] The drive plate 110 is configured to receive torque from the prime mover. Specifically, the drive plate 110 is attached to a crankshaft (not shown) by, for example, a plurality of bolts 111. The drive plate 110 has a plurality of through holes 110a. Each through hole 110a is arranged at intervals in the circumferential direction. The drive plate 110 is disc-shaped.

[0023] [Damper Unit] The damper unit 4 is attached to the torque limiter 3. The damper unit 4 is configured to attenuate rotational fluctuations. The damper unit 4 includes a first rotating member 41, a second rotating member 42, and a plurality of elastic members 43.

[0024] [First Rotating Member] The first rotating member 41 rotates integrally with the friction plate 33 of the torque limiter 3, which will be described later. The first rotating member 41 has a first plate 41a and a second plate 41b. Both the first plate 41a and the second plate 41b are annular members having a central hole. The first plate 41a and the second plate 41b rotate integrally with each other. Furthermore, the first plate 41a and the second plate 41b are immovable relative to each other in the axial direction.

[0025] The first plate 41a and the second plate 41b are arranged with a gap between them in the axial direction. The second plate 41b is positioned on the second side in the axial direction relative to the first plate 41a.

[0026] The first plate 41a and the second plate 41b each have multiple window portions 411a and 411b. In this embodiment, the first plate 41a and the second plate 41b each have four window portions 411a and 411b, but the number is not limited to this.

[0027] Each window section 411a, 411b is spaced apart from each other in the circumferential direction. Each window section 411a, 411b is configured to accommodate an elastic member 43.

[0028] Figure 3 is an enlarged cross-sectional view of the power transmission device 100. As shown in Figure 3, the outer circumferential surface 412 of the first rotating member 41 is in contact with the inner circumferential surface of the second cylindrical portion 322 of the second side plate 32, which will be described later. The outer circumferential surface 412 of the first rotating member 41 is formed by at least one of the outer circumferential surfaces of the first and second plates 41a and 41b.

[0029] As shown in Figure 1, the outer circumferential surface 412 of the first rotating member 41 has a plurality of contact portions 412a and a plurality of non-contact portions 412b. In this embodiment, however, the outer circumferential surface 412 of the first rotating member 41 has four contact portions 412a and four non-contact portions 412b.

[0030] The contact portion 412a extends in an arc shape when viewed in the axial direction. The contact portion 412a is in contact with the inner circumferential surface of the second cylindrical portion 322. The non-contact portion 412b extends in a straight line when viewed in the axial direction. The non-contact portion 412b is not in contact with the inner circumferential surface of the second cylindrical portion 322.

[0031] As shown in Figures 2 and 3, the outer edge of the first rotating member 41 is positioned radially outward relative to the outer edge of the friction plate 33. In an axial view, the outer edge of the first rotating member 41 overlaps with the first fastening member 37, which will be described later. Also, in an axial view, the outer edge of the first rotating member 41 overlaps with the inertia member 36, which will be described later. The outer edge of the first rotating member 41 is positioned on the first axial side relative to the torque limiter 3.

[0032] <Second rotating member> The second rotating member 42 is configured to transmit torque from the first rotating member 41 to the output member. The second rotating member 42 is positioned axially between the first plate 41a and the second plate 41b. The second rotating member 42 is positioned to be rotatable relative to the first plate 41a and the second plate 41b.

[0033] The second rotating member 42 has a hub 421 and a flange plate 422. The hub 421 and the flange plate 422 are configured as separate members, but they may also be formed integrally as a single member.

[0034] The hub 421 is cylindrical and extends axially. The hub 421 is positioned within the central holes of the first plate 41a and the second plate 41b. Spline holes extending axially are formed on the inner circumference of the hub 421. The input shaft of the output-side member can be spline-fitted into these spline holes.

[0035] The flange plate 422 extends radially from the outer circumferential surface of the hub 421. The flange plate 422 is formed in an annular shape. The flange plate 422 is rotatably positioned relative to the first plate 41a and the second plate 41b. In the axial direction, the flange plate 422 is positioned between the first plate 41a and the second plate 41b.

[0036] The flange plate 422 has a plurality of accommodating holes 423. In this embodiment, the flange plate 422 has four accommodating holes 423, but this number is not limited to this. Each accommodating hole 423 is spaced apart from each other in the circumferential direction. Each accommodating hole 423 is configured to accommodate an elastic member 43. Each accommodating hole 423 is positioned to overlap with each window portion 411a, 411b in an axial view.

[0037] <Elastic material> The elastic member 43 is configured to elastically connect the first rotating member 41 and the second rotating member 42 in the rotational direction. The elastic member 43 is, for example, a coil spring.

[0038] The elastic member 43 is housed in the housing hole 423 of the second rotating member 42. The elastic member 43 is also housed in the window portion 411a of the first plate 41a and in the window portion 411b of the second plate 41b.

[0039] [torque limiter] The torque limiter 3 is rotatably positioned around the rotation axis O. The torque limiter 3 is positioned on the first axial side relative to the drive plate 110. The torque limiter 3 is annular in shape. The torque limiter 3 is configured to be mounted on the drive plate 110.

[0040] The torque limiter 3 is configured to limit the torque transmitted between the drive plate 110 and the damper unit 4. In other words, the torque limiter 3 is configured to restrict the transmission of torque exceeding a predetermined value in the power transmission device 100.

[0041] The torque limiter 3 includes a first side plate 31, a second side plate 32, a friction plate 33, a pressure plate 34, a biasing member 35, an inertia member 36, a first fastening member 37, and a second fastening member 38.

[0042] <First side plate> The first side plate 31 is positioned on the first axial side relative to the drive plate 110. That is, the drive plate 110 is positioned on the second axial side relative to the first side plate 31. The first side plate 31 is attached to the drive plate 110. Specifically, the first side plate 31 is attached to the drive plate 110 via an inertia member 36.

[0043] The first side plate 31 rotates integrally with the drive plate 110. The first side plate 31 is annular in shape. The first side plate 31 is thicker than the drive plate 110.

[0044] The first side plate 31 has a first annular portion 311 and a first cylindrical portion 312. The first annular portion 311 and the first cylindrical portion 312 are integrally formed from a single component.

[0045] The first annular portion 311 is an annular shape extending in the circumferential direction. The first annular portion 311 has an intermediate portion 311a, a first inner circumferential portion 311b, and a first outer circumferential portion 311c. The intermediate portion 311a is located radially between the first inner circumferential portion 311b and the first outer circumferential portion 311c. The intermediate portion 311a is located on the second axial side relative to the first outer circumferential portion 311c.

[0046] The first inner circumference portion 311b is positioned radially inward relative to the intermediate portion 311a. The first inner circumference portion 311b is in contact with the friction plate 33. The first inner circumference portion 311b is positioned on the second axial side relative to the intermediate portion 311a.

[0047] The first outer peripheral portion 311c is positioned radially outward relative to the intermediate portion 311a. The first outer peripheral portion 311c is in contact with the inertia member 36.

[0048] The first cylindrical portion 312 extends axially from the outer peripheral end of the first annular portion 311. More specifically, the first cylindrical portion 312 extends axially to the second side from the outer peripheral end of the first annular portion 311. That is, the first cylindrical portion 312 extends axially from the outer peripheral end of the first annular portion 311 toward the drive plate 110. The first cylindrical portion 312 can be formed by bending the outer peripheral portion of the first side plate 31 in the axial direction. The first side plate 31 can be formed by sheet metal processing or press working.

[0049] The first cylindrical portion 312 overlaps with the drive plate 110 in a radial view. More specifically, the tip of the first cylindrical portion 312 (the second axial end) overlaps with the drive plate 110 in a radial view. The outer circumferential surface of the drive plate 110 is in contact with the inner circumferential surface of the first cylindrical portion 312.

[0050] <Second side plate> The second side plate 32 is positioned on the first axial side relative to the first side plate 31. A friction plate 33, a pressure plate 34, and a biasing member 35 are positioned axially between the first side plate 31 and the second side plate 32. The thickness of the second side plate 32 is thinner than the thickness of the first side plate 31.

[0051] The second side plate 32 is configured to rotate integrally with the first side plate 31. The second side plate 32 is fastened to the first side plate 31 by a plurality of first fastening members 37. Each first fastening member 37 is spaced apart in the circumferential direction. The first fastening members 37 are, for example, rivets.

[0052] The second side plate 32 has a second annular portion 321 and a second cylindrical portion 322. The second annular portion 321 and the second cylindrical portion 322 are integrally formed from a single component.

[0053] The second annular portion 321 is an annular shape extending in the circumferential direction. The outer diameter of the second annular portion 321 is approximately the same as the outer diameter of the first annular portion 311. The second annular portion 321 overlaps with the second fastening member 38 in an axial view. The inner diameter of the second annular portion 321 is larger than the inner diameter of the first annular portion 311. The second annular portion 321 has a bulge portion 321a, a second inner circumferential portion 321b, and a second outer circumferential portion 321c.

[0054] The bulging portion 321a is located radially between the second inner circumference portion 321b and the second outer circumference portion 321c. The bulging portion 321a bulges in the axial direction. The bulging portion 321a bulges toward the first side plate 31. That is, the bulging portion 321a bulges toward the second side in the axial direction. The bulging portion 321a is located on the second side in the axial direction relative to the second inner circumference portion 321b and the second outer circumference portion 321c.

[0055] The bulging portion 321a extends in the circumferential direction. The bulging portion 321a is in contact with the intermediate portion 311a in the axial direction. The first fastening member 37 fastens the intermediate portion 311a and the bulging portion 321a together.

[0056] The second inner circumference portion 321b is positioned radially inward relative to the bulging portion 321a. The second inner circumference portion 321b supports the biasing member 35. The second inner circumference portion 321b is positioned at a distance from the first inner circumference portion 311b in the axial direction. The friction plate 33, the pressure plate 34, and the biasing member 35 are positioned between the first inner circumference portion 311b and the second inner circumference portion 321b in the axial direction.

[0057] The second outer periphery 321c is positioned radially outward relative to the bulging portion 321a. The second outer periphery 321c is in contact with the first outer periphery 311c in the axial direction. In an axial view, the second outer periphery 321c overlaps with the first outer periphery 311c and the inertia member 36.

[0058] The second cylindrical portion 322 extends axially from the outer peripheral end of the second annular portion 321 toward the first side. That is, the second cylindrical portion 322 extends axially from the outer peripheral end of the second annular portion 321 so as to move away from the first side plate 31. The second cylindrical portion 322 extends axially in the opposite direction to the first cylindrical portion 312. The second cylindrical portion 322 can be formed by bending the outer peripheral portion of the second side plate 32 in the axial direction. The second side plate 32 can be formed by sheet metal processing or press working.

[0059] The second cylindrical portion 322 is positioned radially outward relative to the first fastening member 37. Furthermore, the second cylindrical portion 322 is positioned radially outward relative to the second fastening member 38. In a radial view, the second cylindrical portion 322 overlaps with the first rotating member 41. The outer circumferential surface 412 of the first rotating member 41 is in contact with the inner circumferential surface of the second cylindrical portion 322.

[0060] <Friction Plate> The friction plate 33 is an annular plate extending in the circumferential direction. The friction plate 33 is rotatably positioned around the axis of rotation O. The friction plate 33 is rotatably positioned relative to the first and second side plates 31 and 32.

[0061] The friction plate 33 is in contact with the first side plate 31 in the axial direction. More specifically, the friction plate 33 is in contact with the first inner circumference 311b of the first annular portion 311 in the axial direction. The friction plate 33 is configured to frictionally engage with the first side plate 31.

[0062] The friction plate 33 is attached to the first rotating member 41. More specifically, the friction plate 33 is attached to the second plate 41b. For example, the friction plate 33 is attached to the second plate 41b by a fastening member 113. The friction plate 33 rotates integrally with the first rotating member 41. Although the friction plate 33 is a separate component from the second plate 41b, the friction plate 33 may be integrally constructed with the second plate 41b as a single component.

[0063] The friction plate 33 comprises a plate body 331, a first friction material 332, and a second friction material 333. The plate body 331 is annular in shape and extends in the circumferential direction. The first friction material 332 is attached to the axial first side surface of the plate body 331. The second friction material 333 is attached to the axial second side surface of the plate body 331. The first and second friction materials 332 and 333 rotate integrally with the plate body 331. The first and second friction materials 332 and 333 are annular in shape. The first and second friction materials 332 and 333 are attached to the outer circumference of the plate body 331.

[0064] <Pressure Plate> The pressure plate 34 is annular in shape. The pressure plate 34 is positioned axially between the biasing member 35 and the friction plate 33. The pressure plate 34 cooperates with the first side plate 31 to clamp the friction plate 33. The first side plate 31 and the pressure plate 34 are in contact with the first and second friction materials 332 and 333.

[0065] The pressure plate 34 is configured to rotate integrally with the first side plate 31. The pressure plate 34 is also movable axially relative to the first side plate 31. Specifically, the pressure plate 34 has a plurality of protrusions 341 that project radially outward (see Figure 2). When these protrusions 341 engage with engagement holes 313 formed in the first side plate 31, the pressure plate 34 rotates integrally with the first side plate 31 while remaining movable axially relative to the first side plate 31.

[0066] <Biasing member> The biasing member 35 is positioned axially between the second side plate 32 and the pressure plate 34. The biasing member 35 biases the pressure plate 34 toward the second axial direction. That is, the biasing member 35 biases the pressure plate 34 toward the first side plate 31. As a result, the friction plate 33 is sandwiched between the pressure plate 34 and the first side plate 31. The biasing member 35 is an annular shape extending in the circumferential direction. The biasing member 35 is, for example, a disc spring. The biasing member 35 is in contact with the second inner circumference portion 321b at its outer circumference end and in contact with the pressure plate 34 at its inner circumference end.

[0067] <Inertia component> The inertia member 36 is annular in shape and extends in the circumferential direction. The thickness of the inertia member 36 is greater than the thickness of the first side plate 31. Note that the thickness of the inertia member 36 refers to the axial dimension. The inertia member 36 is positioned on the second axial side relative to the first side plate 31. In the axial direction, the inertia member 36 is sandwiched between the first side plate 31 and the drive plate 110. Note that another member may be interposed between the inertia member 36 and the first side plate 31, or between the inertia member 36 and the drive plate 110.

[0068] The inertia member 36 is configured to rotate integrally with the first side plate 31. Specifically, the inertia member 36 is fastened to the first side plate 31 by a plurality of second fastening members 38. The second fastening members 38 are, for example, rivets.

[0069] The inertia member 36 is configured to be fixed to the drive plate 110. In detail, the inertia member 36 has a plurality of screw holes 361. The screw holes 361 open on the second axial side. In this embodiment, since the screw holes 361 penetrate the inertia member 36 axially, they also open on the first axial side. The bolt 112 passes through the through hole 110a of the drive plate 110 and is screwed into the screw hole 361 of the inertia member 36. In other words, the bolt 112 fastens the drive plate 110 and the inertia member 36. As a result, the torque limiter 3 is attached to the drive plate 110.

[0070] In a radial view, the inertia member 36 overlaps with the first cylindrical portion 312. More specifically, the outer circumferential surface of the inertia member 36 faces the inner circumferential surface of the first cylindrical portion 312. In an axial view, the inertia member 36 overlaps with the first annular portion 311. More specifically, in an axial view, the inertia member 36 overlaps with the first outer circumferential portion 311c. The inertia member 36 faces the first annular portion 311. Another member may be interposed between the inertia member 36 and the first annular portion 311.

[0071] The inertia member 36 is positioned radially outward relative to the intermediate portion 311a. In the radial direction, the inertia member 36 is positioned between the first cylindrical portion 312 and the intermediate portion 311a. Thus, the inertia member 36 is positioned within the space defined by the first cylindrical portion 312, the first outer peripheral portion 311c, the intermediate portion 311a, and the drive plate 110.

[0072] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. Furthermore, the following modifications can basically be applied simultaneously.

[0073] (a) In the above embodiment, the inertia member 36 was an annular shape extending in the circumferential direction, but the configuration of the inertia member 36 is not limited to this. For example, the inertia member 36 may be composed of a plurality of nuts. Each nut 36 is spaced apart in the circumferential direction. Each nut 36 is thicker than the thickness of the first side plate 31. Each nut 36 may be fixed to the first side plate 31 by welding or the like. Also, the torque limiter 3 does not have to have an inertia member 36.

[0074] (b) In the above embodiment, the first cylindrical portion 312 extends from the first annular portion 311 to the second axial side, but the configuration of the first side plate 31 is not limited thereto. For example, the first cylindrical portion 312 may extend from the outer peripheral end of the first annular portion 311 to the first axial side. In this case, the inertia member 36 can be positioned on the first axial side of the first annular portion 311 so as to overlap with the first cylindrical portion 312 in a radial view. Furthermore, the first side plate 31 does not have to have the first cylindrical portion 312.

[0075] (c) In the above embodiment, the second side plate 32 had approximately the same outer diameter as the first side plate 31, but the configuration of the second side plate 32 is not limited to this. For example, as shown in Figure 4, the second side plate 32 may have a smaller outer diameter than the first side plate 31. The second cylindrical portion 322 is positioned radially inward with respect to the inertia member 36. Specifically, the second cylindrical portion 322 is positioned radially inward with respect to the bolt 114 that fastens the first side plate 31 and the inertia member 36. With this configuration, the first side plate 31 and the inertia member 36 can be fastened together by the bolt 114 from the first side in the axial direction. [Explanation of symbols]

[0076] 3: Torque limiter 31: First side plate 311: First Ring Section 312: First cylindrical section 32: Second side plate 321: Second Ring Section 322: Second cylindrical section 33: Friction Plate 36: Inertia component 361: Screw hole 37: First fastening member 38: Second fastening member 4: Damper Unit 41: First rotating member 412: Outer surface 412a: Contact part 412b: Non-contact part 42: Second rotating member 43: Elastic member 100: Power transmission device 110: Drive Plate

Claims

1. A torque limiter comprising: a first side plate; a second side plate positioned axially on the first side of the first side plate and having a thinner plate thickness than the first side plate; and a friction plate positioned axially between the first and second side plates and rotatable relative to the first and second side plates; A damper unit having a first rotating member configured to rotate integrally with the friction plate, a second rotating member arranged to be rotatable relative to the first rotating member, and an elastic member elastically connecting the first rotating member and the second rotating member, Equipped with, The second side plate has an annular portion extending in the circumferential direction and a cylindrical portion extending from the outer peripheral end of the annular portion toward the first axial direction, The first rotating member has an outer surface that contacts the inner surface of the cylindrical portion. Power transmission device.

2. The outer circumferential surface of the first rotating member is In an axial view, the contact portion extends in an arc shape and abuts against the inner circumferential surface of the cylindrical portion, A non-contact portion that extends linearly in an axial view and does not come into contact with the inner circumferential surface of the cylindrical portion, Having, The power transmission device according to claim 1.

3. The outer edge of the first rotating member is positioned radially outward with respect to the outer edge of the friction plate. The power transmission device according to claim 1.

4. The torque limiter has fastening members that fasten the first side plate and the second side plate together. The cylindrical portion is positioned radially outward with respect to the fastening member. The power transmission device according to claim 1.

5. The torque limiter has an inertia member configured to rotate integrally with the first side plate. The power transmission device according to claim 1.

6. The torque limiter has a fastening member that fastens the first side plate and the inertia member, The cylindrical portion is positioned radially outward with respect to the fastening member. The power transmission device according to claim 5.

7. The inertia member has a screw hole extending in the axial direction. The power transmission device according to claim 5.

8. The inertia member is an annular shape extending in the circumferential direction, The thickness of the inertia member is greater than the thickness of the first side plate. The power transmission device according to claim 5.

9. The inertia member is a nut that is thicker than the thickness of the first side plate. The power transmission device according to claim 5.

10. The system further comprises a drive plate positioned on the second axial side relative to the first side plate, The first side plate is configured to rotate integrally with the drive plate, The inertia member is positioned in the axial direction between the drive plate and the first side plate. The power transmission device according to claim 5.

11. The first side plate has an annular portion extending in the circumferential direction and a cylindrical portion extending from the outer peripheral end of the annular portion to a second axial direction. The power transmission device according to claim 1.

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