Torque limiter

Abstract

To sufficiently secure limit torque of a torque limiter while restraining increase in size of the torque limiter and a device including the same.SOLUTION: A torque limiter includes a first transmission member rotating integrally with one of first and second rotation members and having a pair of first annular tapered surfaces inclined in directions opposite to each other in an extending direction of a rotation axis, a second transmission member rotating integrally with the other of the first and the second rotation members and having a second annular tapered surface which can be in contact with one of the pair of first annular tapered surfaces, a third transmission member having a third annular tapered surface which can be in contact with the other of the pair of first annular tapered surfaces, and a tightening mechanism for tightening the third transmission member. The second and the third transmission members are cylindrical bodies surrounding the first transmission member at least partially and are supported by a columnar surface formed on the first transmission member from a radial inner side.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a torque limiter disposed between a first rotating member to which power is transmitted from a drive source and a second rotating member to which power is transmitted from the first rotating member. [Background technology]

[0002] Conventionally, a drive device is known that includes an input shaft connected to an engine, an electric motor shaft that is an output shaft of a first electric motor (generator), a counter output shaft integrated with a counter drive gear, a planetary gear set that connects the input shaft, the electric motor shaft, and the counter output shaft so as to be capable of transmitting power to each other, a counter shaft including a counter driven gear meshed with the counter drive gear and a differential drive pinion gear, a differential device including a differential ring gear meshed with the differential drive pinion gear, and a second electric motor connected to the counter driven gear via a drive gear (see, for example, Patent Document 1). In this drive device, the tip of the input shaft is connected to the crankshaft of the engine via a damper device including a torque limiter that allows transmission of torque within a predetermined range. The torque limiter includes a dry friction material, and the damper device (torque limiter) is positioned on the outside of the front cover to prevent wear powder generated by wear of the friction material from scattering onto the first and second electric motors, the planetary gear, etc.

[0003] Further, conventionally, a drive device including an input shaft connected to an engine, first and second electric motors, and a planetary gear includes a torque limiter disposed between the rotor shaft of the first electric motor and the sun gear of the planetary gear (see, for example, Patent Document 2). The torque limiter of this drive device is a wet friction engagement device having multiple disc plates, and is disposed inside the case together with the first and second electric motors and the planetary gear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-191760 A [Patent Document 2] Patent No. 5252122 Summary of the Invention [Problem to be solved by the invention]

[0005] In a drive device including a dry torque limiter as described in Patent Document 1, a member (front cover) is required to separate the torque limiter from the drive mechanism in order to deal with the generation of wear powder, making it difficult to prevent the drive device from becoming larger. On the other hand, when a wet torque limiter as described in Patent Document 2 is disposed in a case together with an electric motor and gears that are lubricated and cooled by oil, a partition member such as a front cover is not required. However, in order to sufficiently increase the limit torque of the wet torque limiter, it is necessary to increase the diameter and number of the disk plates, making it difficult to prevent the torque limiter and the entire drive device including it from becoming larger.

[0006] Therefore, a main object of the present disclosure is to sufficiently ensure the limit torque of a torque limiter while suppressing an increase in size of the torque limiter and, in turn, of a device including the torque limiter. [Means for solving the problem]

[0007] The torque limiter disclosed herein is disposed between a first rotating member to which power is transmitted from a drive source and a second rotating member to which power is transmitted from the first rotating member, and includes: a first transmission member that rotates integrally with one of the first and second rotating members and has a pair of first annular tapered surfaces inclined in opposite directions to each other in the extension direction of a rotation shaft; a second transmission member that rotates integrally with the other of the first and second rotating members and has a second annular tapered surface capable of abutting one of the pair of first annular tapered surfaces of the first transmission member; a third transmission member that rotates integrally with the other of the first and second rotating members and has a third annular tapered surface capable of abutting the other of the pair of first annular tapered surfaces of the first transmission member; and a tightening mechanism that tightens the second and third transmission members so that the second annular tapered surface abuts against the one of the pair of first annular tapered surfaces and the third annular tapered surface abuts against the other of the pair of first annular tapered surfaces.

[0008] The torque limiter of the present disclosure is disposed between a first rotating member to which power is transmitted from a drive source and a second rotating member to which power is transmitted from the first rotating member, and includes first, second and third transmission members and a tightening mechanism. The first transmission member rotates integrally with one of the first and second rotating members and has a pair of first annular tapered surfaces inclined in opposite directions in the extending direction of the rotation shaft. The second transmission member rotates integrally with the other of the first and second rotating members and has a second annular tapered surface that can abut against one of the pair of first annular tapered surfaces of the first transmission member. The third transmission member rotates integrally with the other of the first and second rotating members and has a third annular tapered surface that can abut against the other of the pair of first annular tapered surfaces of the first transmission member. The tightening mechanism tightens the second and third transmission members so that the second annular tapered surface abuts on one of the pair of first annular tapered surfaces and the third annular tapered surface abuts on the other of the pair of first annular tapered surfaces. This makes it possible to sufficiently secure the contact area between the pair of first annular tapered surfaces and the second and third annular tapered surfaces while suppressing an increase in the outer diameter of the first, second and third transmission members. Therefore, by applying a sufficient tightening force to the second and third transmission members, it is possible to sufficiently secure the limit torque, which is the upper limit of the torque that does not cause slippage between the pair of first annular tapered surfaces and the second and third annular tapered surfaces. As a result, according to the torque limiter of the present disclosure, it is possible to sufficiently secure the limit torque while suppressing an increase in the size of the torque limiter and the device including it. The torque limiter of the present disclosure may be disposed in a space to which oil is supplied, or may be disposed outside the space to which oil is supplied. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram illustrating a vehicle equipped with a drive device including a torque limiter according to the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view showing a torque limiter according to the present disclosure. [Diagram 3] FIG. 11 is a cross-sectional view showing another torque limiter of the present disclosure. [Figure 4]FIG. 11 is a cross-sectional view showing still another torque limiter of the present disclosure. [Diagram 5] FIG. 11 is a cross-sectional view showing another torque limiter of the present disclosure. [Figure 6] FIG. 11 is a cross-sectional view showing still another torque limiter of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, an embodiment of the present disclosure will be described with reference to the drawings.

[0011] 1 is a schematic configuration diagram showing a vehicle V equipped with a drive unit 1 including a torque limiter 10 according to the present disclosure. The vehicle V is an electric vehicle using a motor generator (rotating electric machine) MG as a drive source, and the drive unit 1 outputs power from the motor generator MG to a pair of drive shafts (output shafts) DS connected to a pair of left and right drive wheels DW of the vehicle V. As shown in FIG. 1, the drive unit 1 includes, in addition to the motor generator MG, a gear train 2 that transmits power (torque) between the motor generator MG and the pair of drive shafts DS, and a case 3 that houses the motor generator MG and the gear train 2.

[0012] The motor generator MG is a synchronous generator motor (three-phase AC motor) including a stator S and a rotor R, and exchanges electric power with an electricity storage device (battery, not shown) via an inverter (not shown). The motor generator MG is driven by electric power from the electricity storage device to operate as an electric motor that generates driving torque, and also outputs regenerative braking torque when braking the vehicle V.

[0013] The stator S includes an annular stator core and three (three-phase) stator coils wound around the stator core, and is fastened (fixed) to the case 3 via a number of bolts (not shown). The rotor R includes an annular rotor core, end plates disposed on both axial sides of the rotor core, and the like, and is fixed to one end of a hollow cylindrical rotor shaft RS. The rotor shaft RS is supported by the case 3 via bearings (not shown) so as to be parallel to and rotatable with the pair of drive shafts DS, and is coaxially connected to a hollow cylindrical input shaft IS via a torque limiter 10.

[0014] The gear train 2 includes a differential gear 25 having a counter drive gear 21, a counter driven gear 22, a drive pinion gear (final drive gear) 23, and a differential ring gear (final driven gear) 24. The counter drive gear 21 is an externally toothed gear that rotates integrally with the input shaft IS. The counter drive gear 21 may be molded integrally with the input shaft IS, or the counter drive gear 21, which is separate from the input shaft IS, may be fixed to the input shaft IS.

[0015] The counter driven gear 22 is an external gear with a larger diameter than the counter drive gear 21 and meshes with the counter drive gear 21. The counter driven gear 22 rotates integrally with the counter shaft CS, which is supported by the case 3 in a manner parallel to and rotatable with the rotor shaft RS, the input shaft IS, and the pair of drive shafts DS. The drive pinion gear 23 is an external gear with a smaller diameter than the counter driven gear 22 and is molded, for example, integrally with the counter shaft CS so as to be located on the opposite side to the counter driven gear 22. As a result, the drive pinion gear 23 rotates coaxially and integrally with the counter driven gear 22 and the counter shaft CS. However, the drive pinion gear 23, which is separate from the counter shaft CS, may be fixed to the counter shaft CS.

[0016] The differential ring gear 24 is an external gear that meshes with the drive pinion gear 23. The differential gear 25 includes a pair (two pieces) of pinion gears, a pair (two pieces) of side gears that are each fixed to the drive shaft DS and mesh with the pair of pinion gears, a pinion shaft that supports the pair of pinion gears, and a differential case (all not shown) that houses the pair of pinion gears and the pair of side gears and to which the differential ring gear 24 is connected (fixed).

[0017] The case 3 is formed by fastening, for example, a housing, a case body, and a cover. In this embodiment, the housing, the case body, and the cover are all cast products made of aluminum alloy. Furthermore, oil for lubrication and cooling is supplied to the motor generator MG, the gear train 2, bearings (not shown), and the like housed in the case 3. In other words, the inside of the case 3 becomes a space to which oil is supplied.

[0018] 2 is a cross-sectional view showing a torque limiter 10 included in the drive device 1. In this embodiment, the torque limiter 10 is disposed between a rotor shaft RS serving as a first rotating member to which power is transmitted from a motor generator MG serving as a drive source, and an input shaft IS serving as a second rotating member to which power is transmitted from the rotor shaft RS. The torque limiter 10 allows the transmission of torque equal to or less than a predetermined limit torque Tlim between the rotor shaft RS and the input shaft IS, and causes slippage between the rotor shaft RS and the input shaft IS in response to an increase in the torque transmitted to the rotor shaft RS or the input shaft IS.

[0019] As shown in Fig. 2, the torque limiter 10 includes a first transmission member 11, a second transmission member 12, a third transmission member 13, and a tightening mechanism 15. The first transmission member 11 is a tubular body made of metal such as steel, and includes a substantially cylindrical tubular portion 110 and an annular protrusion portion 111 protruding radially inward from an inner circumferential surface of the tubular portion 110, as shown in Fig. 2. A spline is formed on the outer circumferential portion of the tubular portion 110, and the first transmission member 11 is connected to a rotor shaft RS serving as a first rotating member via the spline so as to rotate integrally with the rotor shaft RS.

[0020] Moreover, the protrusion 111 is formed with a pair of first annular tapered surfaces 111a, 111b that are inclined in opposite directions to each other in the extending direction of the rotation axis (see the dashed line in FIG. 2) of the first transmission member 11. The first annular tapered surface 111a is an inverted conical surface (inverted tapered surface) with the rotation axis as the central axis and that reduces in diameter from the end portion on the input shaft IS side (left end in FIG. 2) toward the end portion on the rotor shaft RS side (right end in FIG. 2). The first annular tapered surface 111b is an inverted conical surface with the rotation axis as the central axis and that reduces in diameter from the end portion on the rotor shaft RS side (right end in FIG. 2) toward the end portion on the input shaft IS side (left end in FIG. 2).

[0021] The pair of first annular tapered surfaces 111a, 111b are formed symmetrically with respect to a plane that passes through the center in the axial direction of the protrusion 111 and is perpendicular to the rotation axis. That is, the apex angle of the cone that defines the first annular tapered surface 111a is the same as the apex angle of the cone that defines the first annular tapered surface 111b, and the axial length of the first annular tapered surface 111a is the same as the axial length of the first annular tapered surface 111b, L1. Furthermore, the first transmission member 11 (the cylindrical portion 110) is formed with an annular recess 112a that extends along the outer circumferential edge of the first annular tapered surface 111a, and an annular recess 112b that extends along the outer circumferential edge of the first annular tapered surface 111b.

[0022] The second transmission member 12 is a tubular body formed of a metal such as steel, and includes a substantially cylindrical tubular portion 120 and a reduced diameter portion 121 formed at the end of the tubular portion 120 and having a smaller diameter than the tubular portion 120, as shown in FIG. 2. A spline (not shown) is formed on the outer periphery of the end of the tubular portion 120 opposite to the reduced diameter portion 121, and the second transmission member 12 is configured (connected or integrally molded) to rotate integrally with the input shaft IS as a second rotating member via the spline. In addition, a through hole 12h is formed in the tubular portion 120 and the reduced diameter portion 121. Furthermore, a second annular tapered surface 122 is formed on the outer periphery of the end (the right end in FIG. 2) of the tubular portion 120 on the rotor shaft RS side.

[0023] The second annular tapered surface 122 is a conical surface with the rotation axis (see dashed line in FIG. 2) of the second transmission member 12 as the center axis, and the diameter of the second annular tapered surface 122 decreases from the end portion on the input shaft IS side (the left end in FIG. 2) toward the end portion on the rotor shaft RS side (the right end in FIG. 2). The apex angle of the cone defining the second annular tapered surface 122 is the same as the apex angle of the cone defining the first annular tapered surface 111a of the first transmission member 11. As shown in FIG. 2, the axial length L2 of the second annular tapered surface 122 is longer than the axial length L1 of the first annular tapered surface 111a of the first transmission member 11, and the area of ​​the second annular tapered surface 122 is larger than the area of ​​the first annular tapered surface 111a.

[0024] Furthermore, in this embodiment, the hardness of the second annular tapered surface 122 is made higher than the hardness of the first annular tapered surface 111a by varying the heat treatment performed on the first annular tapered surface 111a and the second annular tapered surface 122, or by using a different material for the first transmitting member 11 and the second transmitting member 12. In addition, a seal groove in which a seal member 16 such as a seal ring or an O-ring is disposed is formed on the outer circumferential surface of the cylindrical portion 120 of the second transmitting member 12 so as to be located closer to the input shaft IS side (left side in FIG. 2) than the second annular tapered surface 122.

[0025] The third transmission member 13 is a tubular body formed of a metal such as steel, and includes a substantially cylindrical tubular portion 130 and an extending tubular portion 131 extending in the axial direction from the outer periphery of the end face of the tubular portion 130 on the rotor shaft RS side (the right end in FIG. 2), as shown in FIG. 2. The tubular portion 130 of the third transmission member 13 has an inner diameter slightly larger than the outer diameter of the reduced diameter portion 121 of the second transmission member 12. The extending tubular portion 131 has an outer diameter equal to the outer diameter of the tubular portion 130, and an inner diameter larger than the inner diameter of the tubular portion 130.

[0026] Furthermore, a third annular tapered surface 133 is formed on the outer circumferential surface of the end portion (left end in FIG. 2) of the cylindrical portion 130 on the input shaft IS side. The third annular tapered surface 133 is a conical surface having a central axis that is the rotation axis (see dashed line in FIG. 2) of the third transmitting member 13 and whose diameter decreases from the end portion (right end in FIG. 2) on the rotor shaft RS side toward the end portion (left end in FIG. 2) on the input shaft IS side. The apex angle of the cone that defines the third annular tapered surface 133 is the same as the apex angle of the cone that defines the first annular tapered surface 111b of the first transmitting member 11.

[0027] 2, the axial length L3 of the third annular tapered surface 133 is longer than the axial length L1 of the first annular tapered surface 111b of the first transmitting member 11, and the area of ​​the third annular tapered surface 133 is larger than the area of ​​the first annular tapered surface 111b. Furthermore, in this embodiment, the hardness of the third annular tapered surface 133 is made higher than the hardness of the first annular tapered surface 111b by changing the heat treatment performed on the first annular tapered surface 111b and the third annular tapered surface 133, or by changing the material of the first transmitting member 11 and the material of the third transmitting member 13. In addition, a seal groove in which a seal member 16 such as a seal ring or an O-ring is disposed is formed on the outer circumferential surface of the cylindrical portion 130 of the third transmitting member 13 so as to be located closer to the rotor shaft RS side (the right side in FIG. 2) than the third annular tapered surface 133.

[0028] An end portion of the second transmission member 12 on the reduced diameter portion 121 side is inserted into the first transmission member 11 so that the second annular tapered surface 122 abuts against the first annular tapered surface 111a of the protrusion 111 and the reduced diameter portion 121 is located radially inside the first annular tapered surface 111b of the protrusion 111. In addition, an end portion of the third transmission member 13 on the third annular tapered surface 133 side is inserted into the first transmission member 11 so that the third annular tapered surface 133 abuts against the first annular tapered surface 111b of the protrusion 111. As a result, the first transmission member 11 surrounds a part of the second transmission member 12 and a part of the third transmission member.

[0029] Furthermore, the reduced diameter portion 121 of the second transmission member 12 is fitted into the cylindrical portion 130 of the third transmission member 13, and the cylindrical portion 130 engages with the key 14 held by the reduced diameter portion 121 as a rotation stopper. This restricts the rotation of the third transmission member 13 relative to the second transmission member 12, and the third transmission member 13 is supported by the second transmission member 12 so as to rotate integrally therewith, and is connected to the input shaft IS so as to rotate integrally therewith. However, the second transmission member 12 and the third transmission member 13 may be connected to each other via a spline so as to rotate integrally therewith. The second and third transmission members 12 and 13 are then tightened by the tightening mechanism 15 so that the second annular tapered surface 122 comes into close contact with the first annular tapered surface 111a of the first transmission member 11, and the third annular tapered surface 133 comes into close contact with the first annular tapered surface 111b.

[0030] 2, the tightening mechanism 15 includes a bolt 151, a nut 152, a washer 153, an annular pressing member 154, and an annular disc spring 155 as an elastic member. The bolt 151 is inserted into the through hole 12h through the inside of the cylindrical portion 120 of the second transmission member 12, and the head of the bolt 151 abuts against an end face of the reduced diameter portion 121 surrounding the through hole 12h inside the cylindrical portion 120. In addition, in the extending cylindrical portion 131 of the third transmission member 13, a disc spring 155 is arranged so as to surround the tip of the reduced diameter portion 121 and abut against the end face of the cylindrical portion 130, and a pressing member 154 is arranged so as to abut against the disc spring 155. The tip of reduced diameter portion 121 of second transmission member 12 is reduced in diameter so as not to interfere with disc spring 155, and pressing member 154 abuts on the tip surface of reduced diameter portion 121. In other words, disc spring 155 is disposed between third transmission member 13 and pressing member 154 so as to be located radially outside the abutting portion between pressing member 154 and reduced diameter portion 121 of second transmission member 12.

[0031] The tip of bolt 151 protrudes from reduced diameter portion 121 and pressing member 154 to the rotor shaft RS side (the right side in FIG. 2). A washer 153 is passed through the tip of bolt 151 so as to abut against pressing member 154, and a nut 152 is screwed onto the tip of bolt 151. The second and third transmission members 12, 13 are tightened by the axial force of bolt 151 via pressing member 154 and disc spring 155. The third transmission member 13 is biased by disc spring 155.

[0032] Here, the limit torque Tlim of the torque limiter 10 is a torque transmitted between the rotor shaft RS and the input shaft IS, and is an upper limit value of the torque that does not cause slippage between the pair of first annular tapered surfaces 111a, 111b and the second and third annular tapered surfaces 122, 133. In the torque limiter 10, the limit torque Tlim is determined from the tightening torque of the bolt 151 and the nut 152, the rigidity of the disc spring 155, the contact area and friction coefficient between the first annular tapered surface 111a and the second annular tapered surface 122, the contact area and friction coefficient between the first annular tapered surface 111b and the third annular tapered surface 133, etc.

[0033] 2, when the nut 152 is screwed onto the bolt 151, the recess 112a of the first transmitting member 11 and the outer peripheral surface and part of the second annular tapered surface 122 of the second transmitting member 12 define an annular space 17a extending along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. Furthermore, the seal member 16 disposed in the seal groove of the cylindrical portion 120 of the second transmitting member 12 seals the gap between the cylindrical portion 110 of the first transmitting member 11 and the cylindrical portion 120 of the second transmitting member 12 on the input shaft IS side (left side in FIG. 2) of the annular space 17a. Furthermore, the recess 112b of the first transmitting member 11 and the outer peripheral surface and part of the third annular tapered surface 133 of the third transmitting member 13 define an annular space 17b extending along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. Furthermore, the seal member 16 arranged in the seal groove of the tubular portion 130 of the third transmission member 13 seals the gap between the tubular portion 110 of the first transmission member 11 and the tubular portion 130 of the third transmission member 13 on the rotor shaft RS side (right side in Figure 2) of the annular space 17b.

[0034] In the torque limiter 10 configured as described above, the first transmission member 11 rotates integrally with the rotor shaft RS on the driving side, and has a pair of first annular tapered surfaces 111a, 111b that are inclined in opposite directions to each other in the extending direction of the rotation axis. The second and third transmission members 12, 13 rotate integrally with the input shaft IS on the driven side, and have second and third annular tapered surfaces 122, 133 that can abut against the first annular tapered surface 111a or 111b of the first transmission member 11. Furthermore, the second and third transmission members 12, 13 are tightened by the tightening mechanism 15 so that the second and third annular tapered surfaces 122, 133 abut against the first annular tapered surface 111a or 111b.

[0035] Therefore, when the torque output from the motor generator MG to the rotor shaft RS or the torque transmitted from the drive wheels DW to the input shaft IS becomes equal to or less than the limit torque Tlim while the vehicle V is traveling, the first annular tapered surface 111a and the second annular tapered surface 122 frictionally engage with each other without slipping, and the first annular tapered surface 111b and the third annular tapered surface 133 also frictionally engage with each other without slipping. This causes the first, second and third transmission members 11, 12 and 13 to rotate integrally, allowing transmission of torque equal to or less than the limit torque Tlim between the rotor shaft RS and the input shaft IS.

[0036] In the torque limiter 10, it is possible to sufficiently secure the contact area between the pair of first annular tapered surfaces 111a, 111b and the second and third annular tapered surfaces 122, 133 while suppressing an increase in the outer diameter of the first, second and third transmission members 11, 12, 13. Therefore, by applying a sufficient fastening force to the second and third transmission members 12, 13 by the fastening mechanism 15, it is possible to sufficiently secure the limit torque Tlim, which is the upper limit of the torque that does not cause slippage between the pair of first annular tapered surfaces 111a, 111b and the second and third annular tapered surfaces 122, 133. As a result, the torque limiter 10 makes it possible to sufficiently secure the limit torque Tlim while suppressing an increase in size of the torque limiter 10 and, by extension, the drive device 1 including the torque limiter.

[0037] Furthermore, when the torque output from the motor generator MG to the rotor shaft RS or the torque transmitted from the drive wheels DW side to the input shaft IS exceeds the limit torque Tlim, slippage occurs between the first annular tapered surface 111a and the second annular tapered surface 122 and between the first annular tapered surface 111b and the third annular tapered surface 133. This makes it possible to effectively prevent excessive torque from being transmitted from the motor generator MG to the input shaft IS side or from the drive wheels DW side to the motor generator MG side.

[0038] Furthermore, in the torque limiter 10, the first and second transmission members 11, 12 define an annular space 17a extending along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. The first and third transmission members 11, 13 define an annular space 17b extending along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. This makes it possible to collect wear powder generated between the first annular tapered surface 111a and the second annular tapered surface 122 into the annular space 17a by centrifugal force to suppress discharge to the outside, and to collect wear powder generated between the first annular tapered surface 111b and the third annular tapered surface 133 into the annular space 17b by centrifugal force to suppress discharge to the outside. In addition, the torque limiter 10 can collect wear powder within the gap formed between the second transmission member 12 (cylindrical portion 120) and the third transmission member 13 (cylindrical portion 130) in the axial direction, thereby suppressing its emission to the outside.

[0039] In addition, a seal member 16 that seals the gap between the cylindrical portion 110 of the first transmission member 11 and the cylindrical portion 120 of the second transmission member 12 is arranged on the input shaft IS side (left side in FIG. 2) of the annular space 17a. Furthermore, a seal member 16 that seals the gap between the cylindrical portion 110 of the first transmission member 11 and the cylindrical portion 130 of the third transmission member 13 is arranged on the rotor shaft RS side (right side in FIG. 2) of the annular space 17b. This makes it possible to effectively suppress the discharge of wear powder from the annular spaces 17a, 17b to the outside. Therefore, in the drive device 1 in which the torque limiter 10 is arranged in the same space as the motor generator MG, the gear train 2, etc., i.e., in the case 3, it is possible to effectively suppress the intrusion of wear powder into the periphery of the motor generator MG and the meshing portion between the gears. However, one or both of the two seal members 16 may be omitted from the torque limiter 10.

[0040] In the torque limiter 10, the hardness of the pair of first annular tapered surfaces 111a, 111b is set to be lower than the hardness of the second and third annular tapered surfaces 122, 133. Furthermore, the area of ​​the first annular tapered surface 111a is set to be smaller than the area of ​​the second annular tapered surface 122, and the area of ​​the first annular tapered surface 111b is set to be smaller than the area of ​​the third annular tapered surface 133. As a result, since the first annular tapered surfaces 111a, 111b, which have a smaller area, are worn by contact with the second or third annular tapered surface 122, 133, depressions are formed at the contact portion of the second annular tapered surface 122, which has a larger area, with the first annular tapered surface 111a, and at the contact portion of the third annular tapered surface 133, which has a larger area, with the first annular tapered surface 111b, and it is possible to effectively suppress the accumulation of wear powder in the depressions.

[0041] As a result, it is possible to satisfactorily discharge wear powder from the contact portion between the pair of first annular tapered surfaces 111a, 111b and the second or third annular tapered surface 122, 133. However, in the torque limiter 10, the hardness of the second and third annular tapered surfaces 122, 133 may be set lower than the hardness of the pair of first annular tapered surfaces 111a, 111b. In this case, the area of ​​the second annular tapered surface 122 may be set smaller than the area of ​​the first annular tapered surface 111a, and the area of ​​the third annular tapered surface 133 may be set smaller than the area of ​​the first annular tapered surface 111b.

[0042] Furthermore, in the torque limiter 10, the tightening mechanism 15 includes a pressing member 154, a bolt 151 and a nut 152 that tighten the second and third transmission members 12, 13 via the pressing member 154, and a disc spring 155 as an elastic member that is arranged between the third transmission member 13 and the pressing member 154. This makes it possible to secure a sufficient limit torque Tlim by tightening the second and third transmission members 12, 13 by the axial force of the bolt 151. However, the pressing member 154 may be arranged on the second transmission member 12 side, and the disc spring 155 may be arranged between the second transmission member 12 (for example, the reduced diameter portion 121) and the pressing member 154.

[0043] In the torque limiter 10, the disc spring 155 is disposed between the third transmission member 13 and the pressing member 154, and the pressing member 154 abuts against the second transmission member 12. This makes it possible to reduce the variation in the biasing force applied from the disc spring 155 to the second and third transmission members 12, 13, i.e., the limit torque Tlim, between a plurality of torque limiters 10 having the same structure. Furthermore, the second transmission member 12 may not abut against the pressing member 154, but may face the pressing member 154 via a gap. The disc spring 155 may be omitted from the tightening mechanism 15, and in this case, the pressing member 154 may abut only against the third transmission member 13 and face the second transmission member 12 via a gap.

[0044] 3 is a cross-sectional view showing another torque limiter 10B of the present disclosure. Note that, among the components of the torque limiter 10B, the same components as those of the torque limiter 10 described above are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0045] The torque limiter 10B shown in Fig. 3 includes first, second and third transmission members 11B, 12B and 13B made of metal, and a tightening mechanism 15B. In the torque limiter 10B, a pair of first annular tapered surfaces 111a and 111b formed on a protrusion 111B of the first transmission member 11B are conical surfaces inclined in opposite directions to each other in the extending direction of the rotation shaft. In addition, the second annular tapered surface 122 of the second transmission member 12B and the third annular tapered surface 133 of the third transmission member 13B of the torque limiter 10B are inverted conical surfaces that can come into contact with the first annular tapered surface 111a or 111b. Furthermore, the recess 112a of the first transmission member 11B and the outer peripheral surface of the second transmission member 12B and a part of the second annular tapered surface 122 define an annular space 17a extending along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. The recess 112b of the first transmission member 11B and the outer peripheral surface of the third transmission member 13B and a part of the third annular tapered surface 133 define an annular space 17b extending along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. In addition, in the torque limiter 10B, a gap capable of collecting wear powder is formed between the second transmission member 12B (cylindrical portion 120) and the third transmission member 13 (cylindrical portion 130) in the axial direction. In the torque limiter 10B configured in this manner, it is possible to obtain the same effects as those of the torque limiter 10.

[0046] In the torque limiter 10B, the area of ​​the first annular tapered surface 111a is set smaller than the area of ​​the second annular tapered surface 122, and the area of ​​the first annular tapered surface 111b is set smaller than the area of ​​the third annular tapered surface 133. Therefore, the hardness of the pair of first annular tapered surfaces 111a, 111b is set lower than the hardness of the second and third annular tapered surfaces 122, 133. However, in the torque limiter 10B, the area of ​​the second annular tapered surface 122 may be set smaller than the area of ​​the first annular tapered surface 111a, and the area of ​​the third annular tapered surface 133 may be set smaller than the area of ​​the first annular tapered surface 111b. In this case, the hardness of the second and third annular tapered surfaces 122, 133 may be set lower than the hardness of the pair of first annular tapered surfaces 111a, 111b.

[0047] 4 is a cross-sectional view showing still another torque limiter 10C of the present disclosure. Note that, among the components of the torque limiter 10C, the same components as those of the torque limiter 10 and the like are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0048] The torque limiter 10C shown in FIG. 4 can also be disposed between the rotor shaft RS as a first rotating member of the drive device 1 to which power is transmitted from the motor generator MG and the input shaft IS as a second rotating member to which power is transmitted from the rotor shaft RS. As shown in FIG. 4, the torque limiter 10C includes a first transmission member 11C, a second transmission member 12C, a third transmission member 13C, and a tightening mechanism 15C. The first transmission member 11C is a tubular body formed of a metal such as steel, and is connected to the rotor shaft RS via a spline so as to rotate integrally with the rotor shaft RS. As shown in FIG. 4, the first transmission member 11C includes a substantially cylindrical tubular portion 110 and an annular protrusion portion 111C protruding radially outward from the outer circumferential surface of the tubular portion 110.

[0049] The protrusion 111C is formed with a pair of first annular tapered surfaces 111a, 111b inclined in opposite directions in the extending direction of the rotation axis (see the dashed line in FIG. 4) of the first transmission member 11C. The first annular tapered surface 111a of the first transmission member 11C is a conical surface with the rotation axis as the center axis and the diameter of the surface increases from the end portion on the input shaft IS side (the left end in FIG. 4) toward the end portion on the rotor shaft RS side (the right end in FIG. 4). The first annular tapered surface 111b of the first transmission member 11C is a conical surface with the rotation axis as the center axis and the diameter of the surface increases from the end portion on the rotor shaft RS side (the right end in FIG. 4) toward the end portion on the input shaft IS side (the left end in FIG. 4). The first annular tapered surfaces 111a, 111b of the first transmission member 11C are also formed symmetrically with respect to a plane that passes through the center of the protrusion 111C in the axial direction and is perpendicular to the rotation axis. Furthermore, the first transmission member 11C is formed with an annular recess 112a extending along the inner circumferential edge of the first annular tapered surface 111a, and an annular recess 112b extending along the inner circumferential edge of the first annular tapered surface 111b.

[0050] The second transmission member 12C is a cylindrical body made of a metal such as steel, and is connected to the input shaft IS so as to rotate integrally with the input shaft IS. As shown in FIG. 4, the second transmission member 12C includes a substantially cylindrical cylindrical portion 120 and an expanded diameter portion 125 formed at the end of the cylindrical portion 120 and having an outer diameter and an inner diameter larger than those of the cylindrical portion 120. A second annular tapered surface 122 is formed on the inner circumferential surface of the end (right end in FIG. 4) of the cylindrical portion 120 on the rotor shaft RS side so as to be located closer to the input shaft IS side than the end face of the expanded diameter portion 125. The second annular tapered surface 122 of the second transmission member 12C is an inverted conical surface whose central axis is the rotation axis (see dashed line in FIG. 4) of the second transmission member 12C, and whose diameter expands from the end (left end in FIG. 4) on the input shaft IS side toward the end (right end in FIG. 4) on the rotor shaft RS side. Moreover, the apex angle of the cone that defines the second annular tapered surface 122 of the second transmitting member 12C is the same as the apex angle of the cone that defines the first annular tapered surface 111a of the first transmitting member 11C.

[0051] The third transmission member 13C is a tubular body formed of a metal such as steel, and includes a substantially cylindrical tubular portion 130 and an extending tubular portion 131 extending in the axial direction from the inner periphery of the end face of the tubular portion 130 on the rotor shaft RS side (the right end in FIG. 4). The tubular portion 130 and the extending tubular portion 131 of the third transmission member 13C have an inner diameter slightly larger than the outer diameter of the tubular portion 110 of the first transmission member 11C. Furthermore, a third annular tapered surface 133 is formed on the inner periphery of the end face of the tubular portion 130 on the input shaft IS side (the left end in FIG. 4). The third annular tapered surface 133 is an inverted cone surface with the rotation axis (see the dashed line in FIG. 4) of the third transmission member 13 as the center axis, and the diameter of which increases from the end face on the rotor shaft RS side (the right end in FIG. 2) toward the end face on the input shaft IS side (the left end in FIG. 2). Moreover, the apex angle of the cone that defines the third annular tapered surface 133 is the same as the apex angle of the cone that defines the first annular tapered surface 111 b of the first transmission member 11 .

[0052] In the torque limiter 10C, the area of ​​the second annular tapered surface 122 of the second transmission member 12C is larger than the area of ​​the first annular tapered surface 111a of the first transmission member 11C. In addition, the hardness of the second annular tapered surface 122 of the second transmission member 12C is higher than the hardness of the first annular tapered surface 111a of the first transmission member 11C. In addition, the area of ​​the third annular tapered surface 133 of the third transmission member 13C is larger than the area of ​​the first annular tapered surface 111b of the first transmission member 11C. In addition, the hardness of the third annular tapered surface 133 of the third transmission member 13C is higher than the hardness of the first annular tapered surface 111b of the first transmission member 11C.

[0053] The end portion (left end in FIG. 4) of the first transmission member 11C on the input shaft IS side is inserted into the second transmission member 12C such that the first annular tapered surface 111a of the protrusion 111C abuts against the second annular tapered surface 122 and the first annular tapered surface 111b of the protrusion 111C is surrounded by the enlarged diameter portion 125. The end portion of the third transmission member 13C on the third annular tapered surface 133 side is inserted into the second transmission member 12C such that the third annular tapered surface 133 abuts against the first annular tapered surface 111b of the protrusion 111C. As a result, the second and third transmission members 12C, 13C partially surround the first transmission member 11C.

[0054] Furthermore, the cylindrical portion 130 of the third transmission member 13C is fitted into the enlarged diameter portion 125 of the second transmission member 12C, and the cylindrical portion 130 engages with the key 14 as a rotation stopper held by the enlarged diameter portion 125. This restricts the rotation of the third transmission member 13C relative to the second transmission member 12C, and the third transmission member 13C is supported by the second transmission member 12C so as to rotate integrally therewith, and is connected to the input shaft IS so as to rotate integrally therewith. However, the second transmission member 12C and the third transmission member 13C may be connected to each other via a spline so as to rotate integrally therewith. The second and third transmission members 12C, 13C are then tightened by the tightening mechanism 15C so that the second annular tapered surface 122 comes into close contact with the first annular tapered surface 111a of the first transmission member 11C, and the third annular tapered surface 133 comes into close contact with the first annular tapered surface 111b.

[0055] As shown in FIG. 4, the tightening mechanism 15C includes a plurality of bolts 151, an annular pressing member 154, and an annular disc spring 155 as an elastic member. The disc spring 155 is disposed around the extending tubular portion 131 of the third transmitting member 13C and radially inward of the tip of the expanded diameter portion 125 of the second transmitting member 12C so as to abut against the end face of the tubular portion 130 of the third transmitting member 13C. The pressing member 154 is disposed around the extending tubular portion 131 of the third transmitting member 13C so as to abut against the end face of the expanded diameter portion 125 of the second transmitting member 12C and the disc spring 155. That is, the disc spring 155 is disposed between the third transmitting member 13C and the pressing member 154 so as to be located radially inward of the abutting portion between the pressing member 154 and the expanded diameter portion 125 of the second transmitting member 12C. Furthermore, the bolts 151 are inserted into corresponding through holes formed in the pressing member 154 so that their heads come into contact with the pressing member 154, and are screwed into corresponding screw holes formed in the enlarged diameter portion 125 of the second transmission member 12C. As a result, the second and third transmission members 12C, 13C are tightened by the axial force of the bolts 151 via the pressing member 154 and the disc spring 155. Furthermore, the third transmission member 13C is biased by the disc spring 155.

[0056] 4, when the bolts 151 are screwed into the enlarged diameter portion 125 of the second transmitting member 12C, the recess 112a of the first transmitting member 11C and the inner peripheral surface and part of the second annular tapered surface 122 of the second transmitting member 12C define an annular space 17a extending along the inner circumference of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. Furthermore, the recess 112b of the first transmitting member 11C and the inner peripheral surface and part of the third annular tapered surface 133 of the third transmitting member 13C define an annular space 17b extending along the inner circumference of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133.

[0057] As described above, in the torque limiter 10C, the pair of first annular tapered surfaces 111a, 111b of the first transmission member 11C are held by the second and third annular tapered surfaces 122, 133 on the radially outer side. With this torque limiter 10C, it is possible to obtain the same effect as the torque limiter 10 in which the pair of first annular tapered surfaces 111a, 111b are held by the second and third annular tapered surfaces 122, 133 on the radially inner side. In addition, in the torque limiter 10C, wear powder generated between the first annular tapered surface 111a and the second annular tapered surface 122 is collected in the annular space 17a on the radially inner side to suppress discharge to the outside, and wear powder generated between the first annular tapered surface 111b and the third annular tapered surface 133 is collected in the annular space 17b on the radially inner side to suppress discharge to the outside. Furthermore, in the torque limiter 10C, wear powder can be collected within the gap formed between the second transmission member 12C (cylindrical portion 120) and the third transmission member 13C (cylindrical portion 130) in the axial direction, thereby suppressing its emission to the outside.

[0058] 5 is a cross-sectional view showing another torque limiter 10D of the present disclosure. Note that among the components of the torque limiter 10D, the same components as those of the torque limiter 10C and the like are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0059] The torque limiter 10D shown in Fig. 5 includes first, second and third transmission members 11D, 12D and 13D made of metal, and a tightening mechanism 15D. In the torque limiter 10D, a pair of first annular tapered surfaces 111a and 111b formed on a protrusion 111D of the first transmission member 11D are inverted conical surfaces inclined in opposite directions to each other in the extending direction of the rotation shaft. In addition, the second annular tapered surface 122 of the second transmission member 12D and the third annular tapered surface 133 of the third transmission member 13D of the torque limiter 10D are conical surfaces that can come into contact with the first annular tapered surface 111a or 111b. Furthermore, the torque limiter 10D includes an annular space 17a extending along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122 and an annular space 17b extending along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133, as well as an annular space 17c extending along the inner periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122 and an annular space 17d extending along the inner periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. In addition, in the torque limiter 10D as well, a gap capable of collecting wear powder is formed between the second transmission member 12D (cylindrical portion 120) and the third transmission member 13D (cylindrical portion 130) in the axial direction. In the torque limiter 10D as well, it is possible to obtain the same action and effect as the torque limiter 10C.

[0060] 5, in the torque limiter 10D, the area of ​​the second annular tapered surface 122 is set smaller than the area of ​​the first annular tapered surface 111a, and the area of ​​the third annular tapered surface 133 is set smaller than the area of ​​the first annular tapered surface 111b. Therefore, the hardness of the second and third annular tapered surfaces 122, 133 is set lower than the hardness of the pair of first annular tapered surfaces 111a, 111b. However, in the torque limiter 10D, the area of ​​the first annular tapered surface 111a may be set smaller than the area of ​​the second annular tapered surface 122, and the area of ​​the first annular tapered surface 111b may be set smaller than the area of ​​the third annular tapered surface 133. In this case, the hardness of the pair of first annular tapered surfaces 111a, 111b may be set lower than the hardness of the second and third annular tapered surfaces 122, 133.

[0061] 6 is a cross-sectional view showing still another torque limiter 10E of the present disclosure. Note that among the components of the torque limiter 10E, the same components as those of the torque limiter 10C and the like are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0062] The torque limiter 10E shown in Fig. 6 includes first, second and third transmission members 11E, 12E and 13E made of metal, and a tightening mechanism 15E, and a pair of first annular tapered surfaces 111a and 111b of the first transmission member 11E (projection portion 111E) are held by the second and third annular tapered surfaces 122 and 133 on the radially outer side. As shown in the figure, the tightening mechanism 15E of the torque limiter 10E includes a disc spring 155, a pressing member 156 and a snap ring 157. The pressing member 156 includes a cylindrical portion 156c surrounding the enlarged diameter portion 125 of the second transmission member 12E, and an annular flange portion 156f extending radially inward from the end portion (the right end in Fig. 6) of the cylindrical portion 156c on the rotor shaft RS side. The expanded diameter portion 125 of the second transmission member 12E is fitted into the cylindrical portion 156c of the pressing member 156. The inner surface of the flange portion 156f abuts against the disc spring 155, and the extending cylindrical portion 131 of the third transmission member 13E is fitted into the hole of the flange portion 156f. The pressing member 156 is fixed to the expanded diameter portion 125 of the second transmission member 12E via a snap ring 157 in a state in which the disc spring 155 is compressed together with the third transmission member 13E. The tightening mechanism 15E can also tighten the second and third transmission members 12E and 13E to ensure a sufficient limit torque Tlim. In addition, in the torque limiter 10E, wear powder can be collected within the annular spaces 17a, 17b and within the gap formed in the axial direction between the second transmission member 12E (cylindrical portion 120) and the third transmission member 13E (cylindrical portion 130), thereby suppressing its emission to the outside.

[0063] In the torque limiters 10B, 10C, 10D, and 10E, the disc spring 155 may be disposed between the second transmission members 12B-12E and the pressing member 154, and the pressing member 154 may abut against the third transmission members 13B-13E. Also, the disc spring 155 may be omitted from the tightening mechanisms 15B, 15C, 15D, and 15E, and the pressing member 154 may abut against both the second and third transmission members 12B-12E, 13B-13E. Furthermore, the torque limiters 10B, 10C, 10D, and 10E may include a sealing member that seals the gap between the cylindrical portion 110 of the first transmission member 11B-11E and the cylindrical portion 120 of the second transmission member 12B-12E on the input shaft IS side of the annular space 17a (left side in Figures 3-6), and a sealing member that seals the gap between the cylindrical portion 110 of the first transmission member 11B-11E and the cylindrical portion 130 of the third transmission member 13B-13E on the rotor shaft RS side of the annular space 17b (right side in Figures 3-6).

[0064] In addition, in the torque limiters 10, 10B, 10C, 10D, and 10E, the first transmission member 11-11E, the second transmission member 12-12E, and the third transmission member 13-13E are made of metal, but are not limited to this. That is, the first, second, and third transmission members 11-11E, 12-12E, and 13-13E may be made of a material other than metal that enables frictional engagement between two members, such as resin.

[0065] Furthermore, the first transmission member 11-11E may be connected to the input shaft IS so as to rotate integrally therewith, and the second transmission member 12-12E may be connected to the rotor shaft RS so as to rotate integrally therewith. In addition, in the drive device 1, the countershaft CS may be divided into two, and the torque limiter 10-10E may be disposed between the counter driven gear 22 and the drive pinion gear 23. Furthermore, the torque limiter 10-10E may be applied to a drive device including first and second electric motors and a planetary gear as described in Patent Documents 1 and 2. In this case, the torque limiter 10-10E may be disposed at least in one of the following locations: between the engine (internal combustion engine) and the damper mechanism, between the engine and the damper mechanism and the planetary gear (carrier), between the first electric motor and the planetary gear (sun gear), between the counter drive gear and the counter driven gear, and between the second electric motor and the drive gear (counter driven gear).

[0066] The torque limiter 10-10E may be disposed between an engine (internal combustion engine) that generates power by explosively burning a mixture of air and a hydrocarbon fuel such as gasoline, diesel, or LPG, and a transmission that transmits the power (torque) from the engine to wheels (drive wheels). In this case, the transmission may include a fluid transmission (torque converter), a lock-up clutch, and a stepped or infinitely variable speed mechanism, may include a starting clutch and a stepped or infinitely variable speed mechanism, or may include one motor generator, at least one clutch, and a speed mechanism.

[0067] Furthermore, the torque limiter 10-10E has been described as being disposed inside the case 3 of the drive unit 1, which is a space to which lubricating and cooling oil is supplied, but the present invention is not limited to this. That is, the torque limiter 10-10E may be disposed outside the space to which lubricating and cooling oil or hydraulic oil for engaging a clutch or the like is supplied.

[0068] As described above, the torque limiter of the present disclosure is a torque limiter (10, 10B, 10C, 10D, 10E) disposed between a first rotating member (RS) to which power is transmitted from a drive source (MG) and a second rotating member (IS) to which power is transmitted from the first rotating member (RS), the torque limiter (10, 10B, 10C, 10D, 10E) rotates integrally with one of the first and second rotating members (RS, IS) and is inclined in opposite directions to each other in the extending direction of the rotation axis. a first transmission member (11, 11B, 11C, 11D, 11E) having a pair of first annular tapered surfaces (111a, 111b) that rotate together with the other of the first and second rotating members (RS, IS) and a second transmission member (12, 12E) having a second annular tapered surface (122) that can abut against one of the pair of first annular tapered surfaces (111a, 111b) of the first transmission member (11, 11B, 11C, 11D, 11E); a third transmission member (13, 13B, 13C, 13D, 13E) which rotates integrally with the other of the first and second rotating members (RS, IS) and has a third annular tapered surface (133) which can abut against the other of the pair of first annular tapered surfaces (111a, 111b) of the first transmission member (11, 11B, 11C, 11D, 11E); and a tightening mechanism (15, 15B, 15C, 15D, 15E) which tightens the second and third transmission members (12, 12B, 12C, 12D, 12E, 13, 13B, 13C, 13D, 13E) so that the second annular tapered surface (122) abuts against the one of the pair of first annular tapered surfaces (111a, 111b) and the third annular tapered surface (133) abuts against the other of the pair of first annular tapered surfaces (111a, 111b).

[0069] The torque limiter of the present disclosure is disposed between a first rotating member to which power is transmitted from a drive source and a second rotating member to which power is transmitted from the first rotating member, and includes first, second, and third transmission members made of metal, and a tightening mechanism. The first transmission member rotates integrally with one of the first and second rotating members, and has a pair of first annular tapered surfaces inclined in opposite directions to each other in the extending direction of the rotation shaft. The second transmission member rotates integrally with the other of the first and second rotating members, and has a second annular tapered surface that can abut against one of the pair of first annular tapered surfaces of the first transmission member. The third transmission member rotates integrally with the other of the first and second rotating members, and has a third annular tapered surface that can abut against the other of the pair of first annular tapered surfaces of the first transmission member. The tightening mechanism tightens the second and third transmission members so that the second annular tapered surface abuts on one of the pair of first annular tapered surfaces and the third annular tapered surface abuts on the other of the pair of first annular tapered surfaces. This makes it possible to sufficiently secure the contact area between the pair of first annular tapered surfaces and the second and third annular tapered surfaces while suppressing an increase in the outer diameter of the first, second and third transmission members. Therefore, by applying a sufficient tightening force to the second and third transmission members, it is possible to sufficiently secure the limit torque, which is the upper limit of the torque that does not cause slippage between the pair of first annular tapered surfaces and the second and third annular tapered surfaces. As a result, according to the torque limiter of the present disclosure, it is possible to sufficiently secure the limit torque while suppressing an increase in the size of the torque limiter and the device including it. The torque limiter of the present disclosure may be disposed in a space to which oil is supplied, or may be disposed outside the space to which oil is supplied.

[0070] In addition, the first and second transmission members (11, 11B, 11C, 11D, 11E, 12, 12B, 12C, 12D, 12E) may define an annular space (17a) extending along the outer or inner circumference of a contact portion between the one of the pair of first annular tapered surfaces (111a, 111b) and the second annular tapered surface (122), and the first and third transmission members (11, 11B, 11C, 11D, 11E, 13, 13B, 13C, 13D, 13E) may define an annular space (17b) extending along the outer or inner circumference of a contact portion between the other of the pair of first annular tapered surfaces (111a, 111b) and the third annular tapered surface (133). This makes it possible to collect wear powder generated between one side of the first annular tapered surface and the second annular tapered surface in the annular space defined by the first and second transmission members, thereby suppressing its discharge to the outside, and to collect wear powder generated between the other side of the first annular tapered surface and the third annular tapered surface in the annular space defined by the first and third transmission members, thereby suppressing its discharge to the outside. As a result, when the torque limiter is disposed in the same space as an electric motor, gears, etc., it is possible to suppress wear powder from entering the meshing portion between the electric motor and the gears.

[0071] Furthermore, the pair of annular tapered surfaces (111a, 111b) and the second and third annular tapered surfaces (122, 133) may have different hardnesses, and the area of ​​one of the pair of annular tapered surfaces (111a, 111b) and the second and third annular tapered surfaces (122, 133) having a lower hardness may be smaller than the area of ​​the other of the pair of annular tapered surfaces having a higher hardness. This makes it possible to effectively prevent a recess from being formed at a contact portion between one of the first annular tapered surfaces and the second annular tapered surface and a contact portion between the other of the first annular tapered surface and the third annular tapered surface, and wear powder from accumulating in the recess. As a result, it becomes possible to effectively discharge wear powder from a contact portion between the pair of first annular tapered surfaces and the second or third annular tapered surface.

[0072] The tightening mechanism (15, 15B, 15C, 15D) may include a pressing member (154) and a bolt (151) that tightens the second and third transmission members (12, 12B, 12C, 12D, 13, 13B, 13C, 13D) via the pressing member (154). This makes it possible to tighten the second and third transmission members by the axial force of the bolt, thereby ensuring a sufficient limit torque.

[0073] Furthermore, the tightening mechanism (15, 15B, 15C, 15D) may include an elastic member (155) arranged between one of the second and third transmission members (12, 12B, 12C, 12D, 13, 13B, 13C, 13D) and the pressing member (154).

[0074] Furthermore, the pressing member (154) may be abutted against the second transmission member (12, 12B, 12C, 12D), and the elastic member (155) may be disposed between the third transmission member (13, 13B, 13C, 13D) and the pressing member (154) so ​​as to be located radially outside or inside an abutting portion between the pressing member (154) and the second transmission member (12, 12B, 12C, 12D). This makes it possible to reduce the variation in the biasing force applied from the elastic member to the second and third transmission members, i.e., the limit torque, among a plurality of torque limiters having the same structure.

[0075] Furthermore, the first transmission member (11, 11B) may be a cylindrical body that at least partially surrounds the second and third transmission members (12, 12B, 13, 13B), and one of the second and third transmission members (12, 12B, 13, 13B) may be supported by the other one so as to rotate integrally with the other.

[0076] In addition, the second and third transmission members (12C, 12D, 12E, 13C, 13D, 13E) may be cylindrical bodies at least partially surrounding the first transmission member (11C, 11D, 11E) and may each be supported from the radially inner side by the first transmission member (11C, 11D, 11E).

[0077] Furthermore, the pair of first annular tapered surfaces (111a, 111b) may be inverted conical surfaces inclined in opposite directions, and the second and third annular tapered surfaces (122, 133) may be conical surfaces.

[0078] In addition, the pair of first annular tapered surfaces (111a, 111b) may be conical surfaces inclined in directions opposite to each other, and the second and third annular tapered surfaces (122, 133) may be inverted conical surfaces. [Industrial Applicability]

[0079] The present disclosure is applicable to fields such as torque limiter manufacturing. [Explanation of symbols]

[0080] 1 Drive device, 2 Gear train, 21 Counter drive gear, 22 Counter driven gear, 23 Drive pinion gear, 24 Differential ring gear, 25 Differential gear, 3 Case, 10, 10B, 10C, 10D, 10E Torque limiter, 11, 11B, 11C, 11D, 11E First transmission member, 110 Cylindrical portion, 111, 111B, 111C, 111D, 111E Protrusion, 111a, 111b First annular tapered surface, 112a, 112b Recess, 12, 12B, 12C, 12D, 12E Second transmission member, 12h Through hole, 120 Cylindrical portion, 121 Reduced diameter portion, 122 Second annular tapered surface, 125 Enlarged diameter portion, 13, 13B, 13C, 13D, 13E third transmission member, 130 cylindrical portion, 131 extended cylindrical portion, 133 third annular tapered surface, 14 key, 15, 15B, 15C, 15D, 15E tightening mechanism, 151 bolt, 152 nut, 153 washer, 154, 156 pressing member, 155 disc spring, 156c cylindrical portion, 156f flange portion, 157 snap ring, 16 sealing member, 17a, 17b, 17c, 17d annular space, CS counter shaft, DS drive shaft, DW drive wheel, IS input shaft, MG motor generator, R rotor, RS rotor shaft, S stator, V vehicle.

Claims

1. A torque limiter disposed between a first rotating member to which power is transmitted from a drive source and a second rotating member to which power is transmitted from the first rotating member, a first transmission member that rotates integrally with one of the first and second rotating members and has a pair of first annular tapered surfaces that are inclined in opposite directions to each other in the extending direction of the rotation shaft; a second transmission member that rotates integrally with the other of the first and second rotating members and has a second annular tapered surface that can abut against one of the pair of first annular tapered surfaces of the first transmission member; a third transmission member that rotates integrally with the other of the first and second rotating members and has a third annular tapered surface that can abut against the other of the pair of first annular tapered surfaces of the first transmission member; a tightening mechanism that tightens the second and third transmission members so that the second annular tapered surface abuts against the one of the pair of first annular tapered surfaces and the third annular tapered surface abuts against the other of the pair of first annular tapered surfaces; Equipped with The second and third transmission members are cylindrical bodies that at least partially surround the first transmission member, and each torque limiter is supported from the radially inner side by a cylindrical surface formed on the first transmission member.

2. 2. The torque limiter according to claim 1, the first transmission member includes a protrusion on which the pair of first annular tapered surfaces are formed, The cylindrical surfaces are torque limiters formed on both sides of the protrusion in the extending direction of the rotation shaft.

3. The torque limiter according to claim 1 or 2, the first and second transmission members define an annular space extending along an outer periphery or an inner periphery of a contact portion between the one of the pair of first annular tapered surfaces and the second annular tapered surface, The first and third transmission members are torque limiters that define an annular space extending along the outer or inner circumference of a contact portion between the other of the pair of first annular tapered surfaces and the third annular tapered surface.

4. The torque limiter according to any one of claims 1 to 3, A torque limiter, wherein the pair of first annular tapered surfaces are inverted conical surfaces inclined in opposite directions to each other, and the second and third annular tapered surfaces are conical surfaces.

5. The torque limiter according to any one of claims 1 to 3, A torque limiter, wherein the pair of first annular tapered surfaces are conical surfaces inclined in opposite directions to each other, and the second and third annular tapered surfaces are inverted conical surfaces.

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