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: First and second transmission members of a torque limiter define a first annular space extending along an outer periphery or an inner periphery of a contact portion of one of a pair of first annular tapered surfaces and a second annular tapered surface, the first and third transmission members define a second annular space extending along an outer periphery or an inner periphery of a contact portion of the other of the pair of first annular tapered surfaces and a third annular tapered surface, a gap between the first and the second transmission members is sealed on one side of first and second rotation members in the first annular space, and a gap between the first and the third transmission members is sealed on the other side of the first and the second rotation members in the second annular space.SELECTED DRAWING: Figure 2

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 Art

[0002] Conventionally, a drive device including an input shaft connected to an engine, a motor shaft which is an output shaft of a first electric motor (generator), a counter output shaft integrated with a counter drive gear, and a planetary gear set that connects the input shaft, the motor shaft, and the counter output shaft so as to be capable of power transmission to each other, a counter shaft including a counter driven gear meshing with the counter drive gear and a differential drive pinion gear, a differential device including a differential ring gear meshing with the differential drive pinion gear, and a second electric motor connected to the counter driven gear via a drive gear is known (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 disposed outside the front cover so that wear powder generated by wear of the friction material does not scatter to the first and second electric motors, the planetary gear, etc.

[0003] Also conventionally, as a drive device including an input shaft connected to an engine, first and second electric motors, and a planetary gear, a device including a torque limiter disposed between the rotor shaft of the first electric motor and the sun gear of the planetary gear is known (see, for example, Patent Document 2). The torque limiter of this drive device is a wet friction engagement device having a plurality of disk 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] Japanese Patent Application Laid-Open No. 2003-191760 [Patent Document 2] Japanese Patent No. 5252122 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] In a drive device including a dry torque limiter as described in Patent Document 1 above, in order to deal with the generation of wear powder, a member (front cover) that partitions the torque limiter and the drive mechanism is required, making it difficult to suppress the increase in size of the drive device. On the other hand, when a wet torque limiter as described in Patent Document 2 above is arranged in a case together with an electric motor and gears lubricated and cooled by oil, a partitioning member such as a front cover becomes unnecessary. However, in order to sufficiently increase the limit torque of the wet torque limiter, it is necessary to increase the diameter and number of disk plates, making it difficult to suppress the increase in size of the torque limiter and thus the entire drive device including it.

[0006] Therefore, the main object of the present disclosure is to sufficiently secure the limit torque of the torque limiter while suppressing an increase in size of the torque limiter and thus the device including it. [Means for Solving the Problems]

[0007] In the torque limiter of the present disclosure, which 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, 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 in the extending direction of the rotation axis; 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 contact 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 contact 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 contacts one of the pair of first annular tapered surfaces and the third annular tapered surface contacts 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 that are inclined in opposite directions in the extending direction of the rotation axis. 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 contact 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 contact 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 contacts one of the pair of first annular tapered surfaces and the third annular tapered surface contacts the other of the pair of first annular tapered surfaces. Thereby, while suppressing an increase in the outer diameters of the first, second, and third transmission members, it is possible to sufficiently secure the contact area between the pair of first annular tapered surfaces and the second and third annular tapered surfaces. 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 value 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 thus the device including the same. Note that the torque limiter of the present disclosure may be disposed within a space where oil is supplied or outside the space where oil is supplied.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0010] Next, embodiments for carrying out the invention of the present disclosure will be described with reference to the drawings.

[0011] FIG. 1 is a schematic configuration diagram showing a vehicle V equipped with a drive device 1 including a torque limiter 10 of the present disclosure. The vehicle V is an electric vehicle having a motor generator (rotary electric machine) MG as a drive source, and the drive device 1 outputs power to a pair of drive shafts (output shafts) DS that are connected from the motor generator MG to a pair of left and right drive wheels DW of the vehicle V. As shown in FIG. 1, in addition to the motor generator MG, the drive device 1 includes 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 alternating current motor) including a stator S and a rotor R, and exchanges electric power with a power storage device (battery, not shown) via an inverter not shown. The motor generator MG operates as an electric motor that is driven by the electric power from the power storage device to generate a driving torque, and outputs a regenerative braking torque when the vehicle V is braked.

[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 plurality of bolts (not shown). The rotor R includes an annular rotor core, end plates disposed on both sides in the axial direction of the rotor core, etc., and is fixed to one end of a hollow cylindrical rotor shaft RS. The rotor shaft RS is supported by the case 3 via a bearing (not shown) so as to be parallel and rotatable with respect to a 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 counter drive gear 21, a counter driven gear 22, a drive pinion gear (final drive gear) 23, and a differential gear 25 having a differential ring gear (final driven gear) 24. The counter drive gear 21 is an external gear that rotates integrally with the input shaft IS. The counter drive gear 21 may be integrally formed with the input shaft IS, or a separate counter drive gear 21 may be fixed to the input shaft IS.

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

[0016] The differential gear 24 is an external gear that meshes with the drive pinion gear 23. The differential gear 25 includes a pair (two) of pinion gears, a pair (two) of side gears that are fixed to the drive shaft DS respectively 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 in the figure) 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 constituted by fastening, for example, a housing, a case body, and a cover. In the present embodiment, the housing, the case body, and the cover are all cast products made of an aluminum alloy. Also, oil for lubrication and cooling is supplied to the motor generator MG, the gear train 2, bearings (not shown), etc. accommodated in the case 3. That is, the inside of the case 3 is a space to which oil is supplied.

[0018] Figure 2 is a cross-sectional view showing the torque limiter 10 included in the drive device 1. In the present embodiment, the torque limiter 10 is disposed between the rotor shaft RS as a first rotating member to which power is transmitted from the motor generator MG as a drive source, and the input shaft IS as a second rotating member to which power is transmitted from the rotor shaft RS. The torque limiter 10 allows 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 cylindrical body formed of a metal such as steel. As shown in FIG. 2, it includes a substantially cylindrical tubular portion 110 and an annular protrusion 111 that protrudes radially inward from the inner peripheral surface of the tubular portion 110. Splines are formed on the outer peripheral portion of the tubular portion 110, and the first transmission member 11 is connected to the rotor shaft RS as the first rotating member so as to rotate integrally via the splines.

[0020] Further, on the protrusion 111, a pair of first annular tapered surfaces 111a and 111b that are inclined in opposite directions in the extending direction of the rotation axis (see the dashed-dotted line in FIG. 2) of the first transmission member 11 are formed. The first annular tapered surface 111a is an inverted conical surface (inverted tapered surface) centered on the rotation axis that decreases in diameter from the end on the input shaft IS side (the left end in FIG. 2) toward the end on the rotor shaft RS side (the right end in FIG. 2). Also, the first annular tapered surface 111b is an inverted conical surface centered on the rotation axis that decreases in diameter from the end on the rotor shaft RS side (the right end in FIG. 2) toward the end on the input shaft IS side (the left end in FIG. 2).

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

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

[0023] The second annular tapered surface 122 is a conical surface centered on the rotation axis (see the dashed-dotted line in FIG. 2) of the second transmission member 12 that tapers as it goes from the end on the input shaft IS side (the left end in FIG. 2) to the end 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. Also, 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 the present embodiment, the hardness of the second annular tapered surface 122 is increased compared to the hardness of the first annular tapered surface 111a by changing the heat treatment applied to the first annular tapered surface 111a and the second annular tapered surface 122, or by making the material of the first transmission member 11 different from the material of the second transmission member 12. In addition, a seal groove for arranging a seal member 16 such as a seal ring or an O-ring is formed on the outer peripheral surface of the tubular portion 120 of the second transmission member 12 so as to be located on the input shaft IS side (the left side in FIG. 2) of the second annular tapered surface 122.

[0025] The third transmission member 13 is a cylindrical body formed of a metal such as steel. As shown in FIG. 2, it includes a substantially cylindrical tubular portion 130 and an extended tubular portion 131 extending axially from the outer peripheral portion of the end face on the rotor shaft RS side (the right end in FIG. 2) of the tubular portion 130. 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 extended tubular portion 131 has the same outer diameter as 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 peripheral surface of the end portion on the input shaft IS side (the left end in FIG. 2) of the tubular portion 130. The third annular tapered surface 133 is a conical surface centered on the rotation axis (see the dashed-dotted line in FIG. 2) of the third transmission member 13 whose diameter decreases from the end portion on the rotor shaft RS side (the right end in FIG. 2) toward the end portion on the input shaft IS side (the left end in FIG. 2). The apex angle of the cone defining the third annular tapered surface 133 is the same as the apex angle of the cone defining the first annular tapered surface 111b of the first transmission member 11.

[0027] Also, as shown in FIG. 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 transmission 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 the present embodiment, the hardness of the third annular tapered surface 133 is increased compared to the hardness of the first annular tapered surface 111b by changing the heat treatment applied to the first annular tapered surface 111b and the third annular tapered surface 133, or by changing the material of the first transmission member 11 and the material of the third transmission member 13. In addition, a seal groove for arranging a seal member 16 such as a seal ring or an O-ring is formed on the outer peripheral surface of the tubular portion 130 of the third transmission member 13 so as to be located on the rotor shaft RS side (the right side in FIG. 2) of the third annular tapered surface 133.

[0028] The end of the second transmission member 12 on the side of the reduced-diameter portion 121 is inserted into the inside of the first transmission member 11 such that the second annular tapered surface 122 abuts against the first annular tapered surface 111a of the protruding portion 111 and the reduced-diameter portion 121 is positioned radially inward of the first annular tapered surface 111b of the protruding portion 111. Further, the end of the third transmission member 13 on the side of the third annular tapered surface 133 is inserted into the inside of the first transmission member 11 such that the third annular tapered surface 133 abuts against the first annular tapered surface 111b of the protruding portion 111. Thereby, 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 a key 14 that serves as a rotation stopper held by the reduced-diameter portion 121. Thereby, the rotation of the third transmission member 13 with respect to the second transmission member 12 is restricted, and the third transmission member 13 is supported so as to rotate integrally with the second transmission member 12 and is connected so as to rotate integrally with the input shaft IS. However, the second transmission member 12 and the third transmission member 13 may be connected so as to rotate integrally via a spline. Then, the second and third transmission members 12, 13 are tightened by a tightening mechanism 15 such that the second annular tapered surface 122 is in close contact with the first annular tapered surface 111a of the first transmission member 11 and the third annular tapered surface 133 is in close contact with the first annular tapered surface 111b.

[0030] As shown in Fig. 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 through the through-hole 12h via the inside of the cylindrical portion 120 of the second transmission member 12, and the head of the bolt 151 abuts against the end face of the reduced-diameter portion 121 that surrounds the through-hole 12h within the cylindrical portion 120. Further, within the extended cylindrical portion 131 of the third transmission member 13, the 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 the pressing member 154 is arranged so as to abut against the disc spring 155. The tip of the reduced-diameter portion 121 of the second transmission member 12 is reduced in diameter so as not to interfere with the disc spring 155, and the pressing member 154 abuts against the end face of the reduced-diameter portion 121. That is, the disc spring 155 is arranged between the third transmission member 13 and the pressing member 154 so as to be positioned radially outside the butting portion between the pressing member 154 and the reduced-diameter portion 121 of the second transmission member 12.

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

[0032] Here, the limit torque Tlim of the torque limiter 10 is the torque transmitted between the rotor shaft RS and the input shaft IS, and is the 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 the friction coefficient between the first annular tapered surface 111a and the second annular tapered surface 122, the contact area and the friction coefficient between the first annular tapered surface 111b and the third annular tapered surface 133, and the like.

[0033] Also, as shown in FIG. 2, when the nut 152 is screwed onto the bolt 151, a concave portion 112a of the first transmission member 11, an outer peripheral surface of the second transmission member 12, and a part of the second annular tapered surface 122 define an annular space 17a that extends along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. Further, the seal member 16 disposed in the seal groove of the cylindrical portion 120 of the second transmission member 12 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 on the input shaft IS side (the left side in FIG. 2) of the annular space 17a. Also, a concave portion 112b of the first transmission member 11, an outer peripheral surface of the third transmission member 13, and a part of the third annular tapered surface 133 define an annular space 17b that extends along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. Further, the seal member 16 disposed in the seal groove of the cylindrical portion 130 of the third transmission member 13 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 on the rotor shaft RS side (the right side in FIG. 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 driving-side rotor shaft RS and has a pair of first annular tapered surfaces 111a and 111b that are inclined in opposite directions in the extending direction of the rotation axis. Also, the second and third transmission members 12 and 13 rotate integrally with the driven-side input shaft IS and have second or third annular tapered surfaces 122 and 133 that can abut against the first annular tapered surface 111a or 111b of the first transmission member 11. Further, the second and third transmission members 12 and 13 are tightened by a tightening mechanism 15 so that the second and third annular tapered surfaces 122 and 133 abut against the first annular tapered surface 111a or 111b.

[0035] Therefore, while the vehicle V is running, when the torque output from the motor generator MG to the rotor shaft RS or the torque transmitted from the driving wheel DW side to the input shaft IS is equal to or less than the limit torque Tlim, 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. As a result, the first, second, and third transmission members 11, 12, and 13 rotate integrally, and torque transmission equal to or less than the limit torque Tlim is allowed between the rotor shaft RS and the input shaft IS.

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

[0037] Also, when the torque output from the motor generator MG to the rotor shaft RS or the torque transmitted from the driving wheel DW side to the input shaft IS exceeds the limit torque Tlim, slipping 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. As a result, it is possible to preferably suppress excessive torque from being transmitted from the motor generator MG to the input shaft IS side or from the driving wheel DW side to the motor generator MG side.

[0038] Furthermore, in the torque limiter 10, the first and second transmission members 11 and 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. Also, the first and third transmission members 11 and 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. Thereby, the wear powder generated between the first annular tapered surface 111a and the second annular tapered surface 122 is collected into the annular space 17a by centrifugal force to suppress discharge to the outside, and the wear powder generated between the first annular tapered surface 111b and the third annular tapered surface 133 is collected into the annular space 17b by centrifugal force to suppress discharge to the outside. Also, in the torque limiter 10, it is also possible to collect the wear powder in the gap formed in the axial direction between the second transmission member 12 (cylindrical portion 120) and the third transmission member 13 (cylindrical portion 130) to suppress discharge to the outside.

[0039] In addition, a seal member 16 for sealing 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 disposed on the input shaft IS side (the left side in FIG. 2) of the annular space 17a. Further, a seal member 16 for sealing 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 disposed on the rotor shaft RS side (the right side in FIG. 2) of the annular space 17b. Thereby, it becomes possible to extremely well suppress the discharge of wear powder from the annular spaces 17a and 17b to the outside. Therefore, in the drive device 1 in which the torque limiter 10 is disposed in the same space as the motor generator MG, the gear train 2, etc., that is, inside the case 3, it is possible to well suppress the wear powder from mixing into the periphery of the motor generator MG or 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] Further, in the torque limiter 10, the hardness of the pair of first annular tapered surfaces 111a and 111b is determined to be lower than the hardness of the second and third annular tapered surfaces 122 and 133. Further, the area of the first annular tapered surface 111a is determined to be smaller than the area of the second annular tapered surface 122, and the area of the first annular tapered surface 111b is determined to be smaller than the area of the third annular tapered surface 133. As a result, the first annular tapered surfaces 111a and 111b with a small area are worn due to contact with the second or third annular tapered surfaces 122 and 133. Therefore, it is possible to preferably suppress the formation of depressions at the contact portion between the first annular tapered surface 111a of the second annular tapered surface 122 with a large area and the contact portion between the first annular tapered surface 111b of the third annular tapered surface 133 with a large area and the accumulation of wear powder in the depressions.

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

[0042]

[0043] ​Also, 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. Thereby, it becomes possible to reduce the variation in the biasing force applied from the disc spring 155 to the second and third transmission members 12 and 13, that is, the limit torque Tlim, among a plurality of torque limiters 10 having the same structure. Further, the second transmission member 12 may face the pressing member 154 with a gap therebetween without abutting against the pressing member 154. Also, the disc spring 155 may be omitted from the tightening mechanism 15. In this case, the pressing member 154 may abut only against the third transmission member 13 and may face the second transmission member 12 with a gap therebetween.

[0044] FIG. 3 is a cross-sectional view showing another torque limiter 10B of the present disclosure. Among the components of the torque limiter 10B, the same components as those of the torque limiter 10 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0045] The torque limiter 10B shown in Fig. 3 includes metal first, second, and third transmission members 11B, 12B, 13B, and a tightening mechanism 15B. In such a torque limiter 10B, a pair of first annular tapered surfaces 111a, 111b formed on the protrusion 111B of the first transmission member 11B are conical surfaces that are inclined in opposite directions to each other in the extending direction of the rotation axis. Further, 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 reverse conical surfaces that can contact the first annular tapered surface 111a or 111b. Furthermore, the concave portion 112a of the first transmission member 11B, 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 that extends along the outer periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. Also, the concave portion 112b of the first transmission member 11B, 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 that extends along the outer periphery of the contact portion between the first annular tapered surface 111b and the third annular tapered surface 133. In addition, also in the torque limiter 10B, a gap is formed between the second transmission member 12B (cylindrical portion 120) and the third transmission member 13 (cylindrical portion 130) in the axial direction so that wear powder can be recovered. Even in the torque limiter 10B configured in this way, it is possible to obtain the same operational effects as the above-described torque limiter 10.

[0046] Also, in the torque limiter 10B, the area of the first annular tapered surface 111a is determined to be smaller than the area of the second annular tapered surface 122, and the area of the first annular tapered surface 111b is determined to be 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 determined to be 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 determined to be smaller than the area of the first annular tapered surface 111a, and the area of the third annular tapered surface 133 may be determined to be 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 determined to be lower than the hardness of the pair of first annular tapered surfaces 111a, 111b.

[0047] Figure 4 is a cross-sectional view showing still another torque limiter 10C of the present disclosure. 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 redundant descriptions are omitted.

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

[0049] A pair of first annular tapered surfaces 111a and 111b that are inclined in opposite directions to each other in the extending direction of the rotation axis (see the dashed-dotted line in FIG. 4) of the first transmission member 11C are formed on the protruding portion 111C. The first annular tapered surface 111a of the first transmission member 11C is a conical surface centered on the rotation axis that expands in diameter from the end on the input shaft IS side (the left end in FIG. 4) toward the end on the rotor shaft RS side (the right end in FIG. 4). Also, the first annular tapered surface 111b of the first transmission member 11C is a conical surface centered on the rotation axis that expands in diameter from the end on the rotor shaft RS side (the right end in FIG. 4) toward the end on the input shaft IS side (the left end in FIG. 4). The first annular tapered surfaces 111a and 111b of the first transmission member 11C are also symmetrically formed with respect to a plane passing through the center in the axial direction of the protruding portion 111C and orthogonal to the rotation axis. Further, an annular recess 112a extending along the inner peripheral edge of the first annular tapered surface 111a and an annular recess 112b extending along the inner peripheral edge of the first annular tapered surface 111b are formed in the first transmission member 11C.

[0050] The second transmission member 12C is a cylindrical body formed of a metal such as steel, and is connected to the input shaft IS so as to rotate integrally therewith. As shown in FIG. 4, the second transmission member 12C includes a substantially cylindrical tubular portion 120 and a diameter-expanded portion 125 having an outer diameter and an inner diameter larger than those of the tubular portion 120 formed at an end of the tubular portion 120. On the inner peripheral surface of the end portion (the right end in FIG. 4) of the tubular portion 120 on the rotor shaft RS side, a second annular tapered surface 122 is formed so as to be located on the input shaft IS side with respect to the end surface of the diameter-expanded portion 125. The second annular tapered surface 122 of the second transmission member 12C is an inverted conical surface centered on the rotation axis (see the dashed-dotted line in FIG. 4) of the second transmission member 12C that expands in diameter 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). Further, the apex angle of the cone defining the second annular tapered surface 122 of the second transmission member 12C is the same as the apex angle of the cone defining the first annular tapered surface 111a of the first transmission member 11C.

[0051] The third transmission member 13C is a cylindrical body formed of a metal such as steel, and as shown in FIG. 4, includes a substantially cylindrical tubular portion 130 and an extended tubular portion 131 extending axially from the inner peripheral portion of the end surface on the rotor shaft RS side (the right end in FIG. 4) of the tubular portion 130. The tubular portion 130 and the extended 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. Further, a third annular tapered surface 133 is formed on the inner peripheral surface of the end portion (the left end in FIG. 4) of the tubular portion 130 on the input shaft IS side. The third annular tapered surface 133 is an inverted conical surface centered on the rotation axis (see the dashed-dotted line in FIG. 4) of the third transmission member 13 that expands in diameter from the end portion on the rotor shaft RS side (the right end in FIG. 2) toward the end portion on the input shaft IS side (the left end in FIG. 2). Also, the apex angle of the cone defining the third annular tapered surface 133 is the same as the apex angle of the cone defining the first annular tapered surface 111b 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. Also, the hardness of the second annular tapered surface 122 of the second transmission member 12C is increased compared to the hardness of the first annular tapered surface 111a of the first transmission member 11C. Furthermore, 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. Also, the hardness of the third annular tapered surface 133 of the third transmission member 13C is increased compared to 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 interior of 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. Also, the end portion of the third transmission member 13C on the side of the third annular tapered surface 133 is inserted into the interior of 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. Thereby, 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 a key 14 serving as a rotation stopper held by the enlarged diameter portion 125. Thereby, rotation of the third transmission member 13C relative to the second transmission member 12C is restricted, and the third transmission member 13C is supported so as to rotate integrally with the second transmission member 12C and is connected so as to rotate integrally with the input shaft IS. However, the second transmission member 12C and the third transmission member 13C may be connected so as to rotate integrally via a spline. And the second and third transmission members 12C, 13C are tightened by a tightening mechanism 15C such that the second annular tapered surface 122 closely contacts the first annular tapered surface 111a of the first transmission member 11C and the third annular tapered surface 133 closely contacts 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 extended cylindrical portion 131 of the third transmission member 13C so as to abut against the end face of the cylindrical portion 130 of the third transmission member 13C, and inside the radial direction of the tip of the enlarged diameter portion 125 of the second transmission member 12C. Further, the pressing member 154 is disposed around the extended cylindrical portion 131 of the third transmission member 13C so as to abut against the end face of the enlarged diameter portion 125 of the second transmission member 12C and the disc spring 155. That is, the disc spring 155 is disposed between the third transmission member 13C and the pressing member 154 so as to be located inside the radial direction of the abutting portion between the pressing member 154 and the enlarged diameter portion 125 of the second transmission member 12C. Further, the plurality of bolts 151 are inserted through corresponding through holes formed in the pressing member 154 so that the heads abut against the pressing member 154, and are screwed into corresponding screw holes formed in the enlarged diameter portion 125 of the second transmission member 12C. Thereby, the second and third transmission members 12C, 13C are tightened by the axial force of the plurality of bolts 151 via the pressing member 154 and the disc spring 155. Further, the third transmission member 13C is biased by the disc spring 155.

[0056] Also, as shown in Fig. 4, when the plurality of bolts 151 are screwed into the enlarged diameter portion 125 of the second transmission member 12C, the concave portion 112a of the first transmission member 11C, the inner peripheral surface of the second transmission member 12C, and a part of the second annular tapered surface 122 define an annular space 17a extending along the inner periphery of the contact portion between the first annular tapered surface 111a and the second annular tapered surface 122. Further, the concave portion 112b of the first transmission member 11C, the inner peripheral surface of the third transmission member 13C, and a part of the third annular tapered surface 133 define an annular space 17b extending along the inner periphery 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 and 111b of the first transmission member 11C are held by the second and third annular tapered surfaces 122 and 133 on the radially outer side. Also with such a torque limiter 10C, it is possible to obtain the same operational effects as those of the torque limiter 10 in which the pair of first annular tapered surfaces 111a and 111b are held by the second and third annular tapered surfaces 122 and 133 on the radially inner side. Further, 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 can be collected in the annular space 17b on the radially inner side to suppress discharge to the outside. Moreover, also in the torque limiter 10C, wear powder can be collected in the gap formed in the axial direction between the second transmission member 12C (cylindrical portion 120) and the third transmission member 13C (cylindrical portion 130) to suppress discharge to the outside.

[0058] FIG. 5 is a cross-sectional view showing another torque limiter 10D of the present disclosure. 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 redundant descriptions are 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 such a torque limiter 10D, a pair of first annular tapered surfaces 111a and 111b formed on the protrusion 111D of the first transmission member 11D are reverse conical surfaces that are inclined in opposite directions to each other in the extending direction of the rotation axis. Also, 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 contact the first annular tapered surface 111a or 111b. Further, in addition to the 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 the 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, the torque limiter 10D includes 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, also in the torque limiter 10D, a gap is formed between the second transmission member 12D (cylindrical portion 120) and the third transmission member 13D (cylindrical portion 130) in the axial direction so that wear powder can be recovered. Also in such a torque limiter 10D, it is possible to obtain the same operational effects as those of the above torque limiter 10C.

[0060] Also, as shown in Fig. 5, in the torque limiter 10D, the area of the second annular tapered surface 122 is determined to be smaller than the area of the first annular tapered surface 111a, and the area of the third annular tapered surface 133 is determined to be smaller than the area of the first annular tapered surface 111b. Therefore, the hardness of the second and third annular tapered surfaces 122 and 133 is determined to be lower than the hardness of the pair of first annular tapered surfaces 111a and 111b. However, in the torque limiter 10D, the area of the first annular tapered surface 111a may be determined to be smaller than the area of the second annular tapered surface 122, and the area of the first annular tapered surface 111b may be determined to be 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 and 111b may be determined to be lower than the hardness of the second and third annular tapered surfaces 122 and 133.

[0061] FIG. 6 is a cross-sectional view showing still another torque limiter 10E of the present disclosure. Among the components of the torque limiter 10E, the same components as those of the torque limiter 10C etc. are denoted by the same reference numerals, and redundant descriptions are omitted.

[0062] The torque limiter 10E shown in FIG. 6 includes metal first, second, and third transmission members 11E, 12E, 13E and a tightening mechanism 15E. A pair of first annular tapered surfaces 111a, 111b of the first transmission member 11E (projection portion 111E) are held by second and third annular tapered surfaces 122, 133 on the radially outer side. As shown in the drawing, 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 on the rotor shaft RS side (the right end in FIG. 6) of the cylindrical portion 156c. The enlarged diameter portion 125 of the second transmission member 12E is fitted into the cylindrical portion 156c of the pressing member 156. Further, 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 portion of the flange portion 156f. Further, the pressing member 156 is fixed to the enlarged diameter portion 125 of the second transmission member 12E via the snap ring 157 in a state of compressing the disc spring 155 together with the third transmission member 13E. Also with such a tightening mechanism 15E, it is possible to tighten the second and third transmission members 12E, 13E to ensure a sufficient limit torque Tlim. Also, in the torque limiter 10E, it is possible to collect wear powder in the annular spaces 17a, 17b and in the gap formed axially between the second transmission member 12E (cylindrical portion 120) and the third transmission member 13E (cylindrical portion 130) to suppress discharge to the outside.

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

[0064] Also, in the torque limiters 10, 10B, 10C, 10D, 10E, the first transmission members 11 - 11E, the second transmission members 12 - 12E, and the third transmission members 13 - 13E are formed of metal, but are not limited thereto. That is, the first, second, and third transmission members 11 - 11E, 12 - 12E, 13 - 13E may be formed 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 so as to rotate integrally with the input shaft IS, and the second transmission member 12 - 12E may be connected so as to rotate integrally with the rotor shaft RS. Also, 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. Further, the torque limiter 10 - 10E may be applied to a drive device including the 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 at any one of the following positions: 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] Also, the torque limiter 10 - 10E may be disposed between an engine (internal combustion engine) that generates power by causing an explosive combustion of a mixture of a hydrocarbon - based fuel such as gasoline, light oil, or LPG and air, and a transmission that transmits the power (torque) from the engine to the wheels (drive wheels). In this case, the transmission may include a fluid transmission device (torque converter), a lock - up clutch, and a stepped or continuously variable transmission mechanism, or may include a starting clutch and a stepped or continuously variable transmission mechanism, or may include one motor - generator, at least one clutch, and a transmission mechanism.

[0067] Furthermore, although the torque limiter 10 - 10E has been described as being disposed within the case 3 of the drive device 1, which is a space where lubricating and cooling oil is supplied, it is not limited thereto. That is, the torque limiter 10 - 10E may be disposed outside the space where lubricating and cooling oil or hydraulic oil for engaging clutches and the like is supplied.

[0068] As described above, in the torque limiter of the present disclosure 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), a first transmission member (11, 11B, 11C, 11D, 11E) that rotates integrally with one of the first and second rotating members (RS, IS) and has a pair of first annular tapered surfaces (111a, 111b) inclined in opposite directions in the extending direction of the rotation axis; a second transmission member (12, 12B, 12C, 12D, 12E) that rotates integrally with the other of the first and second rotating members (RS, IS) and has a second annular tapered surface (122) that can contact 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) that rotates integrally with the other of the first and second rotating members (RS, IS) and has a third annular tapered surface (133) that can contact 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) that 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) contacts one of the pair of first annular tapered surfaces (111a, 111b) and the third annular tapered surface (133) contacts 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 that are inclined in opposite directions in the extending direction of the rotation axis. 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 contact 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 contact 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 contacts one of the pair of first annular tapered surfaces and the third annular tapered surface contacts the other of the pair of first annular tapered surfaces. Thereby, while suppressing an increase in the outer diameters of the first, second, and third transmission members, it becomes possible to sufficiently secure the contact area between the pair of first annular tapered surfaces and the second and third annular tapered surfaces. 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 value 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 thus the device including the same. Note that the torque limiter of the present disclosure may be disposed within a space where oil is supplied or outside the space where oil is supplied.

[0070] Further, 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 the contact portion between one of the pair of first annular tapered surfaces (111a, 111b) and the second annular tapered surface (122). 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 the contact portion between the other of the pair of first annular tapered surfaces (111a, 111b) and the third annular tapered surface (133). Thereby, the wear powder generated between one of the first annular tapered surfaces and the second annular tapered surface is collected in the annular space defined by the first and second transmission members to suppress discharge to the outside, and the wear powder generated between the other of the first annular tapered surfaces and the third annular tapered surface is collected in the annular space defined by the first and third transmission members to suppress discharge to the outside. As a result, when the torque limiter is arranged in the same space as an electric motor, gears, etc., it is possible to suppress the wear powder from entering the meshing portions of 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 from each other. The area of the surface with the lower hardness among the pair of annular tapered surfaces (111a, 111b) and the second and third annular tapered surfaces (122, 133) may be smaller than the area of the surface with the higher hardness. Thereby, by the surface with the lower hardness among the pair of annular tapered surfaces and the second and third annular tapered surfaces being worn due to contact with the other, it is possible to preferably suppress the formation of depressions at the contact portions between one of the first annular tapered surfaces and the second annular tapered surface and between the other of the first annular tapered surfaces and the third annular tapered surface, and the accumulation of wear powder in the depressions. As a result, it becomes possible to preferably discharge the wear powder from the contact portions between the pair of first annular tapered surfaces and the second or third annular tapered surfaces.

[0072] Further, 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). Thereby, it becomes possible to tighten the second and third transmission members by the axial force of the bolt and secure sufficient limit torque.

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

[0074] Also, 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 radially inside the abutting portion between the pressing member (154) and the second transmission member (12, 12B, 12C, 12D). Thereby, it becomes possible to reduce the variation in the biasing force applied from the elastic member to the second and third transmission members, that is, the variation in 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 so as to rotate integrally with the other.

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

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

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

Industrial Applicability

[0079] The invention of the present disclosure can be used in the field of manufacturing torque limiters and the like.

Explanation of Reference Numerals

[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 Clamping 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 first and second transmission members define a first 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 define a second annular space extending along an outer periphery or an inner periphery of a contact portion between the other of the pair of first annular tapered surfaces and the third annular tapered surface, A torque limiter in which the first annular space is sealed by contact between the first transmission member and the second transmission member on one side of the first and second rotating members of the first annular space, and the second annular space is sealed by contact between the first transmission member and the third transmission member on the other side of the second annular space of the first and second rotating members.

2. 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 first and second transmission members define a first 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 define a second annular space extending along an outer periphery or an inner periphery of a contact portion between the other of the pair of first annular tapered surfaces and the third annular tapered surface, A torque limiter in which a gap between the first transmission member and the second transmission member on one side of the first and second rotating members in the first annular space is sealed by a first sealing member, and a gap between the first transmission member and the third transmission member on the other side of the first and second rotating members in the second annular space is sealed by a second sealing member.

3. The torque limiter according to claim 1 or 2, the first transmission member is a cylindrical body at least partially surrounding the second and third transmission members, a torque limiter, one of the second and third transmission members being supported by the other so as to rotate integrally therewith;

4. The torque limiter according to claim 1 or 2, The second and third transmission members are cylindrical bodies that at least partially surround the first transmission member, and are torque limiters that are each supported from the radially inner side by the first transmission member.

5. The torque limiter according to any one of claims 1 to 4, 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.

6. The torque limiter according to any one of claims 1 to 4, 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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