Motor unit

Abstract

To provide a motor unit that enables a lubricant to be spread over a gear and a bearing of a deceleration mechanism of the motor unit and that enables stable lubrication and cooling.SOLUTION: An input shaft 21 of a motor unit includes: a hollow hole that extends in the axial direction and in which a lubricant flows; and a through hole 213 penetrating from the hollow hole to a radial outer side and capable of discharging the lubricant to the radial outer side. A planetary carrier includes an opposing part that opposes to the through hole in the radial direction. The opposing part includes: a first flow passage for causing the lubricant discharged from the through hole to flow to one side along a central axis; and a second flow passage for causing the lubricant discharged from the through hole to flow to the other side along the central axis.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a motor unit. [Background technology]

[0002] A structure has been disclosed in which a coolant is cooled by a cooling device provided outside the rotating electric machine, and the coolant is supplied to the motor by a pump provided outside the rotating electric machine (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-73163 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a configuration where the refrigerant is simply supplied to the rotating electrical machine, there is a possibility that oil may not reach each part of the rotating electrical machine sufficiently, resulting in insufficient lubrication and cooling.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a motor unit that can ensure that lubricant is distributed throughout the gears and bearings of the reduction mechanism of the motor unit, and that can be stably lubricated and cooled. [Means for solving the problem]

[0006] An exemplary motor unit of the present invention includes a motor section having a motor shaft extending along a central axis, and a reduction mechanism that reduces the rotation speed of the motor shaft and outputs the reduced rotation speed to the outside. The reduction mechanism includes an input shaft that is rotatable about the central axis and rotates with the rotation of the motor shaft, a sun gear fixed to the input shaft and rotates about the central axis, multiple planetary gears meshing with the sun gear, and a planetary carrier that supports the multiple planetary gears so that they can revolve around the central axis. The input shaft has a hollow hole extending axially through which a lubricant flows, and through holes that extend radially outward from the hollow hole and can discharge the lubricant radially outward. The planetary carrier has an opposing portion radially opposite the through holes. The opposing portion has a first flow path that allows the lubricant discharged from the through holes to flow to one side along the central axis, and a second flow path that allows the lubricant discharged from the through holes to flow to the other side along the central axis. [Effects of the Invention]

[0007] According to the exemplary motor unit of the present invention, it is possible to provide a motor unit that can be stably lubricated and cooled. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a motor unit according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the motor unit taken along a plane including the central axis. [Figure 3] FIG. 3 is a cross-sectional view of the reduction mechanism taken along a plane including the central axis. [Figure 4] FIG. 4 is a cross-sectional perspective view of the first carrier plate with an opposing portion enlarged. [Figure 5] FIG. 5 is an enlarged cross-sectional view of the buffer portion. [Figure 6] FIG. 6 is a cross-sectional perspective view of a first carrier plate used in a planetary gear mechanism according to a first modified example. [Figure 7]FIG. 7 is a cross-sectional perspective view of a first carrier plate used in a planetary gear mechanism according to a second modified example. [Figure 8] FIG. 8 is a cross-sectional perspective view of a first carrier plate used in a planetary gear mechanism according to a third modified example. [Figure 9] FIG. 9 is a schematic development view of the opposing portion of the first carrier plate. [Figure 10] FIG. 10 is an enlarged cross-sectional view of an output shaft used in a planetary gear mechanism according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a motor unit according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention.

[0010] In this specification, the direction parallel to the central axis Ax of the motor shaft 11 of the motor section 100 of the motor unit A is referred to as the "axial direction." The direction perpendicular to the axial direction is referred to as the "radial direction," and the circumferential direction about the central axis Ax is referred to as the "circumferential direction." In the motor unit A, the motor section 100 and the reduction mechanism 200 are connected in the axial direction. In the axial direction, the motor section 100 is disposed on one side of the reduction mechanism 200. In other words, the reduction mechanism 200 is disposed on the other axial side N of the motor section 100. The one axial side T and the other axial side are the same hereinafter.

[0011] Furthermore, in this specification, the term "parallel direction" includes not only completely parallel directions but also approximately parallel directions. Furthermore, the term "extending along" a predetermined direction or plane includes not only extending in a strict predetermined direction but also extending in a direction tilted at an angle of less than 45° relative to the strict direction.

[0012] <Motor unit A> A motor unit A according to an exemplary embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a schematic perspective view of the motor unit A according to one embodiment. Fig. 2 is a schematic cross-sectional view of the motor unit A cut along a plane including the central axis Ax. Note that Fig. 1 is merely a conceptual diagram, and the arrangement and dimensions of each part may not necessarily be the same as those of the actual motor unit A.

[0013] The motor unit A is mounted on a vehicle that uses at least a motor as a power source, such as a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV).

[0014] 1, the motor unit A has a motor section 100 and a speed reduction mechanism 200. In the motor unit A, the speed reduction mechanism 200 reduces the rotation input from the motor shaft 11 and outputs the reduced rotation to the outside.

[0015] <Motor section 100> The motor unit 100 is configured as a DC brushless motor. As shown in Fig. 2, the motor unit 100 has a motor housing 10, a motor shaft 11, a rotor 12, and a stator 15. In the motor unit 100, the rotor 12 rotates when a current is supplied from an inverter (not shown) to a coil 17 (described later) of the stator 15.

[0016] The motor housing 10 has a container portion 101, a lid portion 102, and a motor flange portion 103. The container portion 101 is cylindrical with a closed end on the other axial side N and an open end on one axial side T. The motor shaft 11, rotor 12, and stator 15 of the motor portion 100 are housed in the internal space of the container portion 101. The lid portion 102 covers the opening at the end on the one axial side T of the container portion 101. The lid portion 102 has a motor hole 404 that penetrates in the axial direction. The motor shaft 11 penetrates through the motor hole 404. The motor flange portion 103 extends radially from the end on the other axial side N of the outer circumferential surface of the container portion 101.

[0017] <Motor shaft 11> In the motor section 100 according to this embodiment, the motor shaft 11 is cylindrical. The motor shaft 11 extends along a central axis Ax and rotates about the central axis Ax. The motor shaft 11 is rotatably supported by the container section 101 and the lid section 102 of the motor housing 10 via motor bearings Br. In the motor section 100, the motor shaft 11 passes through a shaft through-hole 104 provided in the bottom of the container section 101 of the motor housing 10 and protrudes to the outside.

[0018] <Rotor 12> The rotor 12 has a rotor core 13 and a magnet 14. The rotor core 13 is fixed to the motor shaft 11. This fixes the rotor 12 to the motor shaft 11. The rotor 12 is rotatable together with the motor shaft 11 about the central axis Ax. The rotor core 13 and the motor shaft 11 can be fixed together by, for example, press fitting, welding, melt-adhering, screw fastening, etc. Furthermore, a wide variety of fixing methods can be used that can firmly fix the motor shaft 11 and the rotor core 13 together. The magnet 14 is fixed to the rotor core 13.

[0019] <Stator 15> The stator 15 has a stator core 16, a coil 17, and an insulator (not shown) interposed between the stator core 16 and the coil 17. The stator 15 is held on the inner circumferential surface of the container portion 101 of the motor housing 10. The stator core 16 has a plurality of magnetic pole teeth (not shown) extending radially inward from the inner circumferential surface of the annular yoke. The coil 17 is formed by winding an electric wire around the magnetic pole teeth. The coil 17 is connected to an inverter unit (not shown).

[0020] <Deceleration mechanism 200> 3 is a cross-sectional view of the reduction gear mechanism 200 taken along a plane including the central axis Ax. The reduction gear mechanism 200 has a planetary gear mechanism 20, an input shaft 21, an output shaft 22, and a gear housing 40.

[0021] <Gear housing 40> As shown in FIG. 3 , the gear housing 40 has a container portion 401, a lid portion 402, and a gear flange portion 403. The container portion 401 is cylindrical with an opening at its end on the other axial side N. An input side hole 45 is formed at the end on one axial side T of the container portion 401, penetrating the container portion 401 in the axial direction. The input shaft 21 passes through the input side hole 45 in the axial direction. The planetary gear mechanism 20 is disposed inside the container portion 401. Note that in the motor unit A according to this embodiment, the gear housing 40 is configured as a separate member from the motor housing 10 and fixed to the motor housing 10, but this is not limiting. For example, the gear housing 40 may be configured as a single member together with the motor housing 10.

[0022] The lid portion 402 covers an opening formed on the other axial side N of the container portion 401. The lid portion 402 has an output-side hole 46 that penetrates in the axial direction. That is, the output-side hole 46 has an inner circumferential surface that faces the outer circumferential surface of the output shaft 22 in the radial direction. The output shaft 22 penetrates the output-side hole 46. That is, the output shaft 22 protrudes to the outside of the gear housing 40. Because the output shaft 22 is configured to protrude from the gear housing 40, the input shaft 21 and the output shaft 22 are aligned coaxially with the motor shaft 11. This allows the motor unit A to be made smaller.

[0023] Furthermore, the gear flange portion 403 extends radially from an end portion on one axial side T of the outer peripheral surface of the container portion 401. The motor flange portion 103 of the motor housing 10 and the gear flange portion 403 of the gear housing 40 are fixed to each other. This fixes the motor housing 10 and the gear housing 40. The motor flange portion 103 and the gear flange portion 403 can be fixed to each other by a wide variety of methods that can firmly fix them, such as screwing, riveting, welding, and melt-bonding.

[0024] The gear housing 40 has a first supply hole 41, a second supply hole 42, a third supply hole 43, and a discharge hole 44. In the gear housing 40, the lubricant CL, which is a fluid, is supplied to the interior of the gear housing 40 through the first supply hole 41, the second supply hole 42, and the third supply hole 43. That is, the supply hole 41 is formed in the gear housing 40, and the lubricant CL flows through it.

[0025] The lubricant CL supplied to the gear housing 40 is discharged to the outside of the gear housing 40 through the discharge hole 44. The first supply hole 41, the second supply hole 42, and the third supply hole 43 are connected via an external piping (not shown). The external piping is provided with a pump and a cooler (not shown). The lubricant CL is forcibly circulated by the pump and cooled as it passes through the cooler. The lubricant CL may be, but is not limited to, lubricating oil. Any configuration that can lubricate and cool members and can flow through the first supply hole 41, the second supply hole 42, the third supply hole 43, and the discharge hole 44 can be widely used.

[0026] The first supply hole 41 is disposed at a position radially opposite the inlet hole 222 of the output shaft 22 in the lid portion 402 of the gear housing 40. The second supply hole 42 and the third supply hole 43 are disposed in the container portion 401 of the gear housing 40, and radially opposite the planetary gear mechanism 20 and the input shaft 21, respectively.

[0027] <Input shaft 21> The center line of the input shaft 21 overlaps with the central axis line Ax. The input shaft 21 is rotatable around the central axis line Ax and is rotated by the rotation of the motor shaft 11. The input shaft 21 has a joint portion 211, a first internal space 212, and a through hole 213. The joint portion 211 is disposed at the end of the input shaft 21 on one axial side T. The motor shaft 11 is connected to the joint portion 211. The rotation of the motor shaft 11 is transmitted to the input shaft 21 via the joint portion 211.

[0028] The first internal space 212 is formed along the axial direction from the end of the input shaft 21 on the other axial side N, and has a concave shape that is closed on one axial side T. A lubricant CL that lubricates and cools each part of the reduction gear mechanism 200 flows in the first internal space 212.

[0029] The through holes 213 open to the first internal space 212 and the outer circumferential surface of the input shaft 21 and extend radially. The lubricant CL flowing in the first internal space 212 is discharged radially outward from the input shaft 21 through the through holes 213. In the reduction gear mechanism 200 according to this embodiment, four through holes 213 are provided at equal intervals in the circumferential direction. However, the number of through holes 213 is not limited to four. When the input shaft 21 rotates about the central axis Ax, centrifugal force acts on the lubricant CL inside the first internal space 212. The lubricant CL is discharged to the outside from the through holes 213 by the centrifugal force. The radially outer end of the through holes 213 faces radially an opposing portion 34 of a second carrier plate 32 of the planet carrier 30, which will be described later.

[0030] That is, the input shaft 21 has an internal space 212 that extends in the axial direction and through which the lubricant CL flows, and a through hole 213 that penetrates radially outward from the internal space 212 and is capable of discharging the lubricant CL radially outward.

[0031] <Output shaft 22> The output shaft 22 has a second internal space 221, an inlet hole 222, and an outlet hole 223. The second internal space 221 is formed along the axial direction from the end of one axial side T of the output shaft 22, and has a concave shape that is closed on the other axial side N. The second internal space 221 extends along the central axis Ax, and the lubricant CL flows through it.

[0032] The inlet hole 222 penetrates radially outward from the second internal space 221, allowing the inflow of lubricant CL. As the output shaft 22 rotates, the opening on the outer peripheral surface side of the inlet hole 222 faces the first supply hole 41 of the gear housing 40 in the radial direction. The lubricant CL supplied from the first supply hole 41 is held in a retention space 54 formed by being sandwiched in the axial direction between a first seal member 511 and a second seal member 512, which will be described later, and flows into the inlet hole 222. Details of the retention space 54 and the buffer portion 50 having the retention space 54 will be described later. The output shaft 22 according to this embodiment has four inlet holes 222. The four inlet holes 222 are arranged at equal intervals in the circumferential direction.

[0033] The outflow holes 223 are formed in a portion of the planetary carrier 30 (described later) attached to an end of one axial side T of the output shaft 22, where a second carrier plate 32 (described later) is attached. The outflow holes 223 are through holes that connect the second internal space 221 and the outer circumferential surface of the output shaft 22 and extend in the radial direction. The output shaft 22 has four outflow holes 223. The four outflow holes 223 are arranged side by side at equal intervals in the circumferential direction. The number of outflow holes 223 is not limited to four, but may be the same as the number of planetary gears 24 (described later) of the planetary gear mechanism 20. Each outflow hole 223 is connected to a plate outflow hole 322 of the second carrier plate 32 so that the lubricant CL can flow.

[0034] The end portion of the input shaft 21 on the other axial side N and the end portion of the output shaft 22 on the one axial side T are opposed to each other in the axial direction with a gap therebetween. The first internal space 212 of the input shaft 21 has a larger inner diameter than the second internal space 221 of the output shaft 22.

[0035] The lubricant CL is supplied from the output shaft 22 and flows into the input shaft 21. Therefore, in the reduction gear mechanism 200, a connecting pipe 26 is attached to the opening of the second internal space 221 at the end of the output shaft 22 on one axial side T, in other words, the end facing the input shaft 21. The connecting pipe 26 is cylindrical and contacts the inner circumferential surface of the second internal space 221. This prevents the lubricant CL from leaking from a gap between the inner circumferential surface of the second internal space 221 and the connecting pipe 26. The end of the connecting pipe 26 on the one axial side T is inserted into the first internal space 212 of the input shaft 21.

[0036] A gap is formed between the outer peripheral surface of the communication pipe 26 and the inner peripheral surface of the first internal space 212 of the input shaft 21. By providing the communication pipe 26, it is possible to allow the lubricant CL to flow from the second internal space 221 of the output shaft, which rotates at a different rotational speed from the input shaft 21, into the first internal space 212 of the rotating input shaft 21.

[0037] <Planetary gear mechanism 20> The planetary gear mechanism 20 transmits the rotation of the input shaft 21 to the output shaft 22. At this time, the planetary gear mechanism 20 decelerates the rotation of the input shaft 21 and transmits it to the output shaft 22. In the planetary gear mechanism 20, the rotation of the input shaft 21 is decelerated and the torque of the input shaft 21 is increased and transmitted to the output shaft 22. The planetary gear mechanism 20 has a sun gear 23, planet gears 24, a ring gear 25, and a planet carrier 30.

[0038] <Sun Gear 23> As shown in FIG. 3 , the sun gear 23 is fixed to the input shaft 21 and rotates together with the input shaft 21 about the central axis Ax. That is, the sun gear is rotated by the rotation of the motor shaft 11. The sun gear 23 is formed separately from the input shaft 21 and fixed to the input shaft 21. The sun gear 23 can be fixed by, for example, press-fitting, welding, melt-bonding, adhesive, screwing, etc., but is not limited to these. The method of fixing the sun gear 23 to the input shaft 21 can be any method that can firmly fix them. Furthermore, the input shaft 21 and the sun gear 23 may be formed from a single member.

[0039] <Planetary Gear 24> The planetary gear mechanism 20 has a plurality of planetary gears 24 that mesh with the sun gear 23. In this example, there are four planetary gears 24, which are arranged at equal intervals in the circumferential direction. The planetary gears 24 are attached to the planet carrier 30 via planetary shafts 33 and planetary bearings 332.

[0040] <Planet Carrier 30> The planetary carrier 30 supports the four planetary gears 24 so that they can revolve around the central axis Ax. The planetary carrier 30 has a first carrier plate 31, a second carrier plate 32, and a planetary shaft 33. The first carrier plate 31 is disposed on one axial side T of the sun gear 23. The first carrier plate 31 is supported by the container portion 401 of the gear housing 40 via a first bearing 61 so that it can rotate around the central axis Ax. In addition, a second bearing 62 is disposed between the first carrier plate 31 and the input shaft 21.

[0041] As a result, the input shaft 21 is rotatably supported by the container portion 401 of the gear housing 40 via the first bearing 61, the first carrier plate 31, and the second bearing 62.

[0042] The first carrier plate 31 has an inner flange portion 310 that extends radially inward. The inner flange portion 310 has an opposing portion 34 on the radially inner side that faces the through hole 213 of the input shaft 21 in the radial direction. In other words, the planetary carrier 30 has the opposing portion 34 that faces the through hole 213 in the radial direction.

[0043] The second carrier plate 32 is disposed on the other axial side N of the sun gear 23. The second carrier plate 32 is supported by the cover portion 402 of the gear housing 40 via a third bearing 63 so as to be rotatable about the central axis Ax. Furthermore, the output shaft 22 is fixed to the second carrier plate 32. That is, the output shaft 22 is rotatably supported by the gear housing 40, and is rotated by the planetary carrier 30 so as to be rotatable about the central axis Ax.

[0044] The method for fixing the output shaft 22 and the second carrier plate 32 can be, for example, press-fitting, welding, melt-bonding, adhesive, screwing, etc., but is not limited to these. Any fixing method that can firmly fix the output shaft 22 and the second carrier plate 32 can be widely used.

[0045] The output shaft 22 is fixed to the second carrier plate 32, and the second carrier plate 32 is attached to the cover portion 402 of the gear housing 40 via a third bearing 63. This allows the output shaft 22 to rotate together with the second carrier plate 32 about the central axis Ax.

[0046] The second carrier plate 32 has plate outlet holes 322 extending in the radial direction. The plate outlet holes 322 intersect with the second shaft hole 321 of the second carrier plate 32. In other words, the plate outlet holes 322 open onto the inner circumferential surface of the second shaft hole 321.

[0047] The first carrier plate 31 and the second carrier plate 32 are fixed to each other with a fixed distance maintained in the axial direction. In this embodiment, the first carrier plate 31 is fixed to a support column (not shown) provided on the second carrier plate 32. However, this configuration is not limited to this, and for example, the support column may be formed separately from the first carrier plate 31 and the second carrier plate 32, and the first carrier plate 31 and the second carrier plate 32 may be fixed to the support column. Although screw fastening is used as the fastening method, the method is not limited to screw fastening and any method that can securely fasten the plates can be widely used. However, in consideration of maintainability, it is preferable that the first carrier plate 31 and the second carrier plate 32 be detachable.

[0048] The planetary shafts 33 are inserted into and fixed in the first shaft holes 311 of the first carrier plate 31. The planetary shafts 33 are inserted into and fixed in the second shaft holes 321 of the second carrier plate 32. Methods for fixing the planetary shafts 33 to the first shaft holes 311 and the second shaft holes 321 include, for example, press fitting, welding, melt-adhesion, and adhesive. The fixing method is not limited to these methods, and any method that can firmly fix the planetary shafts 33 to the first carrier plate 31 and the second carrier plate 32 can be used. The planetary gears 24 are rotatably supported on the planetary shafts 33 via planetary bearings 332.

[0049] The central portion of the planetary shaft 33 has a shaft internal space 331 extending in the axial direction. The shaft internal space 331 is open to one axial side T. The planetary shaft 33 also has a shaft inlet hole 333 and a shaft outlet hole 334 extending radially to connect the shaft internal space 331 to the outer circumferential surface. When the planetary shaft 33 is inserted into and fixed in the second shaft hole 321 of the second carrier plate 32, the shaft inlet hole 333 is connected to the plate outlet hole 322. This allows the lubricant CL flowing through the plate outlet hole 322 to flow into the shaft internal space 331 via the shaft inlet hole 333.

[0050] The lubricant CL flows in the axial direction in the shaft internal space 331. A portion of the lubricant CL flows out onto the outer circumferential surface of the planetary shaft 33 through the shaft outflow hole 334 and is supplied to the planetary bearing 332. The planetary bearing 332 is lubricated and cooled by the supplied lubricant CL. This allows the planetary gear 24 to rotate smoothly. The lubricant CL flows out from an opening at an end on one axial side T of the shaft internal space 331 to the outside. The lubricant CL that flows out from the end on one axial side T of the shaft internal space 331 flows into the other axial side N of the first bearing 61 and lubricates and cools the first bearing 61.

[0051] <Ring gear 25> The ring gear 25 is annular. The ring gear 25 has an internal gear formed on its inner circumferential surface. The internal gear of the ring gear 25 meshes with the planetary gears 24. The ring gear 25 is fixed to the container portion 401 of the gear housing 40.

[0052] The rotation of the motor shaft 11 is transmitted to the input shaft 21. When the input shaft 21 rotates, the sun gear 23 rotates about the central axis Ax, and the rotation is transmitted to the planetary gears 24. The planetary gears 24 rotate on their own axis and move along the internal gears formed on the inner circumferential surface of the ring gear 25 fixed to the container portion 401 of the gear housing 40. This causes the planet carrier 30 that supports the planetary gears 24 to rotate about the central axis Ax. As a result, the rotation of the input shaft 21 is transmitted to the output shaft 22. In the planetary gear mechanism 20, the rotation speed of the input shaft 21 is reduced by a reduction ratio determined by the number of teeth of the sun gear 23 and the number of teeth of the ring gear 25, and then transmitted to the output shaft 22.

[0053] <About circulation using lubricant CL> The planetary gear mechanism 20 is disposed inside the gear housing 40. A lubricant CL is disposed inside the gear housing 40. The lubricant CL lubricates and cools the sun gear 23, planet gears 24, and ring gear 25 that constitute the planetary gear mechanism 20. The lubricant CL also lubricates and cools the first bearing 61, the second bearing 62, and the third bearing 63. The lubricant CL also cools the input shaft 21 and the output shaft 22. Each member is cooled by the lubricant CL, thereby suppressing expansion due to temperature rise. Furthermore, the lubricated members are lubricated by the lubricant CL, thereby suppressing wear.

[0054] To explain in more detail, the lubricant CL supplied from the second supply hole 42 is poured into the planetary gear mechanism 20. The lubricant CL poured into the planetary gear mechanism 20 flows through gaps in the planetary gear mechanism 20 to the sun gear 23, the planet gears 24, and the ring gear 25. The lubricant CL supplied from the second supply hole 42 also flows to the third bearing 63. As a result, the lubricant CL lubricates the meshing portions between the sun gear 23 and the planet gears 24 and the meshing portions between the planet gears 24 and the ring gear 25. The sun gear 23, the planet gears 24, the ring gear 25, and the third bearing 63 are also cooled.

[0055] Furthermore, the lubricant CL supplied from the third supply hole 43 flows into the input shaft 21. Furthermore, the lubricant CL flows from the input shaft 21 into the first bearing 61. As a result, the lubricant CL cools the input shaft 21 and the first bearing 61, and lubricates the first bearing 61.

[0056] The lubricant CL is supplied to the surface of the input shaft 21 from the third supply hole 43. The lubricant CL on the surface of the input shaft 21 is sent radially outward by centrifugal force caused by rotation. Therefore, in the planetary gear mechanism 20, the lubricant CL is less likely to be supplied to the sun gear 23 and the second bearing 62, which are arranged in contact with the input shaft 21. In other words, there are cases where the lubricant CL supplied from the second supply hole 42 and the third supply hole 43 is less likely to reach them.

[0057] In the planetary gear mechanism 20 according to this embodiment, the lubricant CL is supplied to the second internal space 221 of the output shaft 22. The lubricant CL supplied to the second internal space 221 flows into the first internal space 212 of the input shaft 21 via the connecting pipe 26. The lubricant CL supplied to the first internal space 212 is then discharged to the outside via the through-hole 213, thereby allowing the lubricant CL to reach the meshing portions between the sun gear 23 and the planetary gears 24 and the second bearing 62.

[0058] A configuration for spreading the lubricant CL discharged from the first internal space 212 of the input shaft 21 through the through-holes 213 will be described with reference to the drawings. Fig. 4 is a perspective view of the first carrier plate 31 with the opposing portion 34 enlarged.

[0059] 4, the opposing portion 34 provided on the inner circumferential surface of the inner flange portion 310 of the first carrier plate 31 faces the through hole 213 of the input shaft 21 in the radial direction. The opposing portion 34 has a first flow path 341 and a second flow path 342. The first flow path 341 allows the lubricant CL discharged from the through hole 213 to flow to one side T along the central axis Ax. The second flow path 342 allows the lubricant CL discharged from the through hole 213 to flow to the other side N along the central axis Ax.

[0060] 4, the first flow path 341 has a first tapered surface 343 whose inner diameter increases toward one axial side T. The second flow path 342 has a second tapered surface 344 whose inner diameter increases toward the other axial side N.

[0061] In the opposing portion 34, the first flow passage 341 is disposed adjacent to one axial side T of the second flow passage 342. That is, a ridge portion 345 is formed where the end portion of the first tapered surface 343 on the other axial side N and the end portion of the second tapered surface 344 on the one axial side T are continuous in the circumferential direction.

[0062] 3, the ridge portion 345 of the opposing portion 34 radially overlaps with the through hole 213 of the input shaft 21. When the input shaft 21 rotates, centrifugal force acts on the lubricant CL flowing into the first internal space 212. The centrifugal force causes the lubricant CL to be discharged radially outward from the input shaft 21 through the through hole 213.

[0063] Since the through hole 213 faces the ridge portion 345 in the radial direction, the lubricant CL is discharged from the through hole 213 toward the ridge portion 345. The ridge portion 345 is a connecting portion between the first tapered surface 343 and the second tapered surface 344. Therefore, part of the lubricant CL flows into the first flow path 341 having the first tapered surface 343, and the rest flows into the second flow path 342 having the second tapered surface 344.

[0064] When the input shaft 21 rotates, the first carrier plate 31 also rotates, and therefore centrifugal force acts on the lubricant CL that flows into the first flow passage 341 and the second flow passage 342 of the opposing portion 34. The lubricant CL that flows into the first flow passage 341 is pushed radially outward by the centrifugal force and toward the one axial side T by the first tapered surface 343. As a result, the lubricant CL that flows into the first flow passage 341 is supplied to the other axial side N of the second bearing 62 that is disposed on the one axial side T relative to the first carrier plate 31. Furthermore, the lubricant CL that flows into the second flow passage 342 is pushed radially outward by the centrifugal force and toward the other axial side N by the second tapered surface 344. As a result, the lubricant CL that flows into the second flow passage 342 flows to the meshing portion between the sun gear 23 and the planetary gear 24 that are disposed on the other axial side N relative to the first carrier plate 31.

[0065] As described above, the through hole 213 of the input shaft 21 and the opposing portion 34 of the first carrier plate 31 allow the lubricant CL to be supplied to the meshing portion between the sun gear 23 and the planetary gears 24 and to the second bearing 62. This allows the sun gear 23, the planetary gears 24, and the second bearing 62 to be lubricated and cooled.

[0066] The amount of lubricant CL flowing to one axial side T and the amount flowing to the other axial side can be adjusted by changing the relative positions of the through hole 213 and the ridge portion 345. That is, by shifting the portion of the through hole 213 that intersects with the opposing portion 34 toward the one axial side T, the amount of lubricant CL flowing into the first flow passage 341 can be increased. Conversely, by shifting the portion of the through hole 213 that intersects with the opposing portion toward the other axial side N, the amount of lubricant CL flowing into the second flow passage 342 can be increased. The relative positions of the through hole 213 and the ridge portion 345 can be adjusted by changing the relative positions of the input shaft 21 and the first carrier plate 31. Alternatively, the axial lengths of the first flow passage 341 and the second flow passage 342 may be changed to shift the axial position of the ridge portion 345 with respect to the through hole 213.

[0067] As described above, the lubricant CL flowing through the first internal space 212 of the input shaft 21 is supplied to the meshing portion between the sun gear 23 and the planetary gears 24 and the second bearing 62. The lubricant CL is supplied from the second internal space 221 of the output shaft 22 through the connecting pipe 26 to the first internal space 212 of the input shaft 21. The lubricant CL is supplied from the first supply hole 41 arranged in the lid portion 402 of the gear housing 40 to the second internal space 221 through the inlet hole 222 of the output shaft 22.

[0068] In the reduction gear mechanism 200, the output shaft 22 rotates, but the first supply hole 41 does not rotate. Therefore, when the output shaft 22 is rotating, the inlet hole 222 does not radially oppose the first supply hole 41. Therefore, the reduction gear mechanism 200 according to this embodiment has a buffer portion 50 which is an annular space formed on the outer peripheral surface of the output shaft 22 and connected to the inlet hole 222, and which has a holding space 54 capable of holding the lubricant CL.

[0069] The buffer portion 50 will be described with reference to the drawings. Fig. 5 is an enlarged cross-sectional view of the buffer portion 50. As shown in Fig. 5, the output-side hole 46 of the cover portion 402 of the gear housing 40 has a protruding portion 47 formed in an axially intermediate portion thereof that protrudes radially inward and continues around the entire circumferential direction. That is, the inner circumferential surface of the output-side hole 46 has the protruding portion 47 that protrudes radially inward from the axially intermediate portion thereof. The first supply hole 41 opens to the radially inner surface of the protruding portion 47.

[0070] 5, the buffer unit 50 has a first seal member 511, a second seal member 512, a first fixed member 521, a second fixed member 522, and an external seal member 53. The first seal member 511 and the second seal member 512 are annular plates. The first seal member 511 and the second seal member 512 can be made of, for example, silicone rubber, fluororubber, chloroprene rubber, nitrile rubber, fluororesin, or the like. Materials other than these can also be widely used as long as they suppress the flow of the lubricant CL and are elastically deformable.

[0071] A radially outer portion of the first seal member 511 contacts a first contact surface 471 on one axial side T of the protruding portion 47. A radially inner portion of the first seal member 511 is curved toward the other axial side N and contacts the outer peripheral surface of the output shaft 22. That is, the first seal member 511 is annular and fixed to the output-side hole 46, with its radially inner end portion contacting the outer peripheral surface of the output shaft 22. The first seal member 511 is disposed on the one axial side T of the inlet hole 222 and the first supply hole 41, and its radially inner end portion is curved toward the second seal member 512.

[0072] A radially outer portion of the second seal member 512 contacts a second contact surface 472 on the other axial side N of the protrusion 47. A radially inner portion of the second seal member 512 is curved toward the one axial side T and contacts the outer peripheral surface of the output shaft 22. That is, the second seal member 512 is annular and is fixed closer to the other axial side N than the first seal member 511 of the output-side hole 46, and its radially inner end portion contacts the outer peripheral surface of the output shaft 22. The second seal member 512 is disposed closer to the other axial side N than the inlet hole 222 and the first supply hole 41, and its radially inner end portion curves toward the first seal member 511.

[0073] That is, the radially inner end of the first seal member 511 curves toward the second seal member 512 and comes into contact with the output shaft 22. In addition, the radially inner end of the second seal member 512 curves toward the first seal member 511 and comes into contact with the output shaft 22.

[0074] The first fixing member 521 is annular. The inner diameter of the inner circumferential surface of the first fixing member 521 is larger than the outer diameter of the output shaft 22. The first fixing member 521 is fixed to the one axial side T of the output-side hole 46 relative to the protrusion 47. When the first fixing member 521 is fixed to the inner circumferential surface of the output-side hole 46, the inner circumferential surface of the first fixing member 521 does not contact the outer circumferential surface of the output shaft 22. The first fixing member 521 can be fixed to the inner circumferential surface of the output-side hole 46 by, for example, press-fitting, welding, adhesive bonding, etc., but is not limited to these. A wide variety of fixing methods can be used that firmly fix the first fixing member 521 to the inner circumferential surface of the output-side hole 46. When the first fixing member 521 is fixed to the inner circumferential surface of the output-side hole 46, the first seal member 511 is sandwiched and fixed between the first fixing member 521 and the first contact surface 471 of the protrusion 47.

[0075] The second fixing member 522 is annular. The inner diameter of the inner circumferential surface of the second fixing member 522 is larger than the outer diameter of the output shaft 22. The second fixing member 522 is fixed to the other axial side N of the protrusion 47 of the output-side hole 46. The second fixing member 522 is fixed to the cover portion 402 at a position adjacent to the other axial side N of the protrusion 47 on the inner circumferential surface of the output-side hole 46. When the second fixing member 522 is fixed to the inner circumferential surface of the output-side hole 46, the inner circumferential surface of the second fixing member 522 does not come into contact with the outer circumferential surface of the output shaft 22. The second fixing member 522 can be fixed to the inner circumferential surface of the output-side hole 46 by, for example, press-fitting, welding, adhesive bonding, etc., but is not limited to these methods. A wide variety of fixing methods can be used as long as the second fixing member 522 is firmly fixed to the inner circumferential surface of the output-side hole 46. When the second fixing member 522 is fixed to the inner circumferential surface of the output-side hole 46, the second sealing member 512 is sandwiched and fixed between the second fixing member 522 and the second contact surface 472 of the protruding portion 47.

[0076] As a result, the first seal member 511 and the second seal member 512 are fixed by the first fixing member 521 and the second fixing member 522, respectively, and therefore the first seal member 511 and the second seal member 512 can be easily attached.

[0077] Furthermore, an external seal member 53 is disposed at the end of the cover portion 402 on the other axial side N of the output-side hole 46. The external seal member 53 is cylindrical. Examples of materials for the external seal member 53 include silicone rubber, fluororubber, chloroprene rubber, nitrile rubber, and fluororesin. The radial outer edge of the external seal member 53 is fixed to the inner circumferential surface of the output-side hole 46. The radial inner edge of the external seal member 53 contacts the outer circumferential surface of the output shaft 22. At this time, the output shaft 22 is in rotatable contact with the radial inner edge of the external seal member 53. Thus, provision of the external seal member 53 prevents the lubricant CL from leaking outside the gear housing 40. Note that if the output shaft 22 does not protrude outside the gear housing 40, the output-side hole 46 and the external seal member 53 can be omitted.

[0078] 5, in the buffer portion 50, the space surrounded by the outer circumferential surface of the output shaft 22, the inner circumferential surface of the protruding portion 47, the first seal member 511, and the second seal member 512 is the retaining space 54. In other words, the retaining space 54 is surrounded by the inner circumferential surface of the output-side hole 46, the first seal member 511, the second seal member 512, and the outer circumferential surface of the output shaft 22.

[0079] A radially inner opening of the first supply hole 41 is disposed between the first seal member 511 and the second seal member 512 in the axial direction. Therefore, the lubricant CL supplied from the first supply hole 41 flows into the retention space 54. Furthermore, a radially outer opening of the inlet hole 222 of the output shaft 22 is disposed between the first seal member 511 and the second seal member 512 in the axial direction. In other words, the inlet hole 222 is connected to the retention space 54.

[0080] In the reduction gear mechanism 200, the lubricant CL is forcibly supplied by a pump (not shown). That is, the lubricant CL is forcibly supplied into the retention space 54 from the first supply hole 41. Therefore, even after the retention space 54 is filled with the lubricant CL, the lubricant CL continues to be supplied by the pump, and the pressure of the lubricant CL increases.

[0081] The radial outsides of the first seal member 511 and the second seal member 512 are fixed to the lid portion 402. Therefore, even if the pressure of the lubricant CL increases inside the retention space 54, the lubricant CL is unlikely to leak from between the lid portion 402 and the first seal member 511 and the second seal member 512.

[0082] An increase in the pressure of the lubricant CL in the retention space 54 elastically deforms the first seal member 511 and the second seal member 512. The radially inner end of the first seal member 511 is bent toward the other axial side N and comes into contact with the outer circumferential surface of the output shaft 22. The radially inner end of the second seal member 512 is bent toward the one axial side T and comes into contact with the outer circumferential surface of the output shaft 22. Therefore, even if the first seal member 511 and the second seal member 512 are elastically deformed due to an increase in the pressure of the lubricant CL, the radially inner end of the first seal member 511 is unlikely to separate from the outer circumferential surface of the output shaft 22. Similarly, the radially inner end of the second seal member 512 is unlikely to separate from the outer circumferential surface of the output shaft 22. This suppresses leakage of the lubricant CL from between the first seal member 511 and the second seal member 512 and the output shaft 22.

[0083] For these reasons, when the lubricant CL is supplied to the retention space 54 from the first supply hole 41, the lubricant CL is less likely to leak outside the retention space 54 even if the pressure of the lubricant CL in the retention space 54 rises within a certain range.

[0084] Furthermore, when the lubricant CL is supplied from the first supply hole 41, the output shaft 22 is rotating. For example, assume that the lubricant CL is present in the inlet hole 222. At this time, as the output shaft 22 rotates, a centrifugal force acts on the lubricant CL in the inlet hole 222, and a force acting radially outward acts on the lubricant CL in the inlet hole 222.

[0085] As described above, the inlet hole 222 is connected to the retention space 54. Therefore, when the pressure of the lubricant CL in the retention space 54 increases and becomes greater than the pressure due to centrifugal force, the lubricant CL retained in the retention space 54 flows into the second internal space 221 through the inlet hole 222. In this way, by using the retention space 54, the lubricant CL can be caused to flow from the outer circumferential surface of the rotating output shaft 22 into the second internal space 221 through the inlet hole 222 opening on the outer circumferential surface. As a result, the lubricant CL can be stably supplied from the first supply hole 41 formed in the gear housing 40 to the output shaft 22, which has a portion protruding outside the gear housing 40.

[0086] In the reduction gear mechanism 200 according to this embodiment, the lubricant CL necessary for lubrication and cooling can be supplied to the gears 23, 24, and 25 and the bearings 61, 62, and 63 of the planetary gear mechanism 20. This reduces wear on the various parts of the planetary gear mechanism 20. It also reduces deformation of the planetary gear mechanism 20 due to temperature rise. This reduces a decrease in rotation and torque of the motor unit A.

[0087] <First Modification> Fig. 6 is a cross-sectional perspective view of a first carrier plate 31a used in a planetary gear mechanism according to a first modified example. As shown in Fig. 6, an inner flange portion 310 of the first carrier plate 31a of the first modified example differs from the first carrier plate 31 in that it has an opposing portion 35. In all other respects, the first carrier plate 31a has the same configuration as the first carrier plate 31. Therefore, portions of the first carrier plate 31a that are substantially the same as those of the first carrier plate 31 are denoted by the same reference numerals, and detailed description of the same portions will be omitted.

[0088] 6, the opposing portion 35 has a first flow path 351 and a second flow path 352. The first flow path 351 has a first tapered surface 353 whose inner diameter increases toward one axial side T. The second flow path 352 has a second tapered surface 354 whose inner diameter increases toward the other axial side N. The first flow paths 351 and the second flow paths 352 are arranged alternately in the circumferential direction.

[0089] The first carrier plate 31a rotates together with the output shaft 22. Furthermore, the rotation of the input shaft 21 is decelerated and transmitted to the output shaft 22 by the planetary gear mechanism. Therefore, the rotation speed of the input shaft 21 and the rotation speed of the first carrier plate 31a differ. In this state, when the input shaft 21 and the first carrier plate 31a rotate while the lubricant CL is discharged from the through holes 213, the position at which the lubricant CL discharged from the through holes 213 flows into the opposing portion 35 moves in the circumferential direction. In other words, the lubricant CL discharged from the through holes 213 flows alternately into the first flow path 351 and the second flow path 352.

[0090] As a result, the lubricant CL that has flowed into the first flow passage 351 flows to the one axial side T and enters the other axial side N of the second bearing 62. In addition, the lubricant CL that has flowed into the second flow passage 352 flows to the other axial side N and is supplied to the portion where the sun gear 23 and the planetary gears 24 mesh. In this way, the lubricant CL discharged from the through hole 213 is supplied to the portion where the sun gear 23 and the planetary gears 24 mesh and to the second bearing 62, thereby preventing a shortage of the lubricant CL.

[0091] In the first carrier plate 31a according to this modification, the ratio between the first flow passages 351 and the second flow passages 352 in the circumferential direction is equal. However, the ratio between the first flow passages 351 and the second flow passages 352 does not have to be equal. For example, by making the circumferential ratio of the first flow passages 351 larger than the circumferential ratio of the second flow passages 352, more lubricant CL is supplied to the second bearing 62. Furthermore, by making the circumferential ratio of the first flow passages 351 smaller than the circumferential ratio of the second flow passages 352, more lubricant CL is supplied to the portion where the sun gear 23 and the planetary gears 24 mesh.

[0092] In the planetary gear mechanism 20 configured according to this embodiment, the lubricant CL is more likely to run out at the bearing than at the meshing portion between the gears, resulting in insufficient lubrication and cooling. Therefore, the proportion of the circumferential area of ​​the facing portion 35 occupied by the first tapered surface 353 is made larger than the proportion occupied by the second tapered surface 354. This allows more lubricant CL to be supplied to the second bearing 62 than to the meshing portion between the sun gear 23 and the planetary gears 24.

[0093] <Second Modification> Fig. 7 is a cross-sectional perspective view of a first carrier plate 31b used in a planetary gear mechanism according to a second modified example. As shown in Fig. 7, the inner flange portion 310 of the first carrier plate 31b of the second modified example differs from the first carrier plate 31 in that it has an opposing portion 36. In all other respects, the first carrier plate 31b has the same configuration as the first carrier plate 31. Therefore, portions of the first carrier plate 31b that are substantially the same as those of the first carrier plate 31 are denoted by the same reference numerals, and detailed description of the same portions will be omitted.

[0094] 7, the facing portion 36 has a recess 360 recessed radially outward from the inner circumferential surface of the inner flange portion 310. The recess 360 is a groove-like shape that continues in the circumferential direction. That is, the facing portion 36 has the recess 360 that is recessed radially and continues in the circumferential direction in the axial center portion. The facing portion 36 has a first flow path 361 and a second flow path 362.

[0095] The first flow passage 361 is groove-shaped recessed radially outward and has a plurality of first grooves 363 connecting the recess 360 and an end portion on one axial side T of the first carrier plate 31b. Similarly, the second flow passage 362 is groove-shaped recessed radially outward and has a plurality of second grooves 364 connecting the recess 360 and an end portion on the other axial side N of the first carrier plate 31b. That is, the first flow passage 361 has a plurality of first grooves 363 extending from the recess 360 toward the one axial side T. Furthermore, the second flow passage 362 has a plurality of second grooves 364 extending from the recess 360 toward the other axial side N. Note that in the first carrier plate 31b, the total number of first grooves 363 and the total number of second grooves 364 are the same.

[0096] The through hole 213 faces the recess 360 in the radial direction. The lubricant CL discharged from the through hole 213 flows into the recess 360. Centrifugal force acts on the lubricant CL that has flowed into the recess 360, and the lubricant CL is pushed radially outward from the recess 360. As a result, the lubricant CL pushed radially outward flows to one axial side T through the first groove 363 of the first flow passage 361 and flows into the other axial side N of the second bearing 62. The lubricant CL also flows to the other axial side N through the second groove 364 of the second flow passage 362 and is supplied to a portion where the sun gear 23 and the planetary gear 24 mesh.

[0097] In the first carrier plate 31b according to this modification, the ratio between the sum of the circumferential lengths of the first grooves 363 of the first flow passage 361 and the sum of the circumferential lengths of the second grooves 364 of the second flow passage 362 is equal. However, the ratio between the sum of the circumferential lengths of the first grooves 363 of the first flow passage 361 and the sum of the circumferential lengths of the second grooves 364 of the second flow passage 362 does not have to be equal. For example, by making the ratio of the sum of the circumferential lengths of the first grooves 363 of the first flow passage 361 larger than the ratio of the sum of the circumferential lengths of the second grooves 364 of the second flow passage 362, a larger amount of lubricant CL is supplied to the second bearing 62. Furthermore, by making the ratio of the sum of the circumferential lengths of the first grooves 363 of the first flow passage 361 smaller than the ratio of the sum of the circumferential lengths of the second grooves 364 of the second flow passage 362, a larger amount of lubricant CL is supplied to the portion where the sun gear 23 and the planetary gear 24 mesh.

[0098] The ratio may be adjusted by adjusting the circumferential length of each of the first grooves 363 and the second grooves 364, or by changing the total number of each of the first grooves 363 and the second grooves 364. The ratio may also be adjusted by shifting the first grooves 363 and the second grooves 364 in the circumferential direction.

[0099] In this way, the lubricant CL discharged from the through hole 213 is supplied to the portion where the sun gear 23 and the planetary gear 24 mesh and to the second bearing 62, so that shortage of the lubricant CL is suppressed.

[0100] <Third Modification> Fig. 8 is a cross-sectional perspective view of a first carrier plate 31c used in a planetary gear mechanism according to a third modified example. Fig. 9 is a schematic development view of a facing portion 37 of the first carrier plate 31c. As shown in Fig. 8, the inner flange portion 310 of the first carrier plate 31c of the third modified example differs from the first carrier plate 31 in that it has a facing portion 37. In all other respects, the first carrier plate 31c has the same configuration as the first carrier plate 31. Therefore, parts of the first carrier plate 31c that are substantially the same as those of the first carrier plate 31 are given the same reference numerals, and detailed descriptions of the same parts will be omitted.

[0101] As shown in Figures 8 and 9, the opposing portion 37 has a first flow path 371 and a second flow path 372. The first flow path 371 has a first peripheral wall 373 and a first guide wall 374. The first peripheral wall 373 protrudes radially from an end of the opposing portion 37 on the other axial side N. The first peripheral wall 373 extends in the circumferential direction. The first guide wall 374 is continuous with the rear side of the first peripheral wall 373 in the rotation direction Rt of the planet carrier 30, and extends toward the one axial side T as it moves toward the rear side in the rotation direction Rt of the planet carrier 30.

[0102] The second flow passage 372 has a second peripheral wall 375 and a second guide wall 376. The second peripheral wall 375 protrudes radially from an end of the opposing portion 37 on one axial side T. The second peripheral wall 375 extends in the circumferential direction. The second guide wall 376 is continuous with the rear side of the second peripheral wall 375 in the rotation direction Rt of the planet carrier 30, and extends toward the other axial side N as it moves toward the rear side in the rotation direction Rt of the planet carrier 30. The first flow passage 371 and the second flow passage 372 are arranged side by side in the circumferential direction.

[0103] The first carrier plate 31c rotates together with the output shaft 22. Furthermore, the rotation of the input shaft 21 is decelerated and transmitted to the output shaft 22 by the planetary gear mechanism. Therefore, the rotation speed of the input shaft 21 and the rotation speed of the first carrier plate 31c differ. In this state, when the input shaft 21 and the first carrier plate 31c rotate while the lubricant CL is discharged from the through holes 213, the position at which the lubricant CL discharged from the through holes 213 flows into the opposing portions 37 moves in the circumferential direction. In other words, the lubricant CL discharged from the through holes 213 flows alternately into the first flow paths 371 and the second flow paths 372.

[0104] In the first flow passage 371, a first peripheral wall 373 is arranged on the other axial side N. Therefore, the flow of the lubricant CL that has flowed into the first flow passage 371 toward the other axial side N is suppressed. Furthermore, when the first carrier plate 31c rotates, the lubricant CL moves rearward in the rotation direction Rt relative to the opposing portion 37. Then, when the lubricant CL comes into contact with the first guide wall 374, it is pushed toward the one axial side T by the first guide wall 374 while moving rearward in the rotation direction Rt. As a result, the lubricant CL that has flowed into the first flow passage 371 flows toward the one axial side T and flows from the other axial side N into the second bearing 62.

[0105] Similarly, the lubricant CL that has flowed into the second flow passage is prevented from flowing toward the one axial side T by the second peripheral wall 375. Then, due to the rotation of the first carrier plate 31c, the lubricant CL moves rearward relative to the opposing portion 37, comes into contact with the second guide wall 376, and is then pushed toward the other axial side N by the second guide wall 376. As a result, the lubricant CL that has flowed into the second flow passage 372 flows toward the other axial side N, and flows from the one axial side T into the portion where the sun gear 23 and the planetary gears 24 mesh with each other.

[0106] In this way, the lubricant CL discharged from the through hole 213 is supplied to the portion where the sun gear 23 and the planetary gear 24 mesh and to the second bearing 62, so that shortage of the lubricant CL is suppressed.

[0107] In the first carrier plate 31c according to this modification, the ratio between the sum of the circumferential lengths of the first flow passages 371 and the sum of the circumferential lengths of the second flow passages 372 is equal. However, the ratio between the sum of the circumferential lengths of the first flow passages 371 and the sum of the circumferential lengths of the second flow passages 372 does not have to be equal. For example, by making the ratio of the sum of the circumferential lengths of the first flow passages 371 larger than the ratio of the sum of the circumferential lengths of the second flow passages 372, more lubricant CL is supplied to the second bearing 62. Furthermore, by making the ratio of the sum of the circumferential lengths of the first flow passages 371 smaller than the ratio of the sum of the circumferential lengths of the second flow passages 372, more lubricant CL is supplied to the portion where the sun gear 23 and the planetary gears 24 mesh.

[0108] Furthermore, in the first carrier plate 31c, no components are arranged in positions that overlap in the axial direction with the first peripheral wall 373 and first guide wall 374 of the first flow path 371. Similarly, no components are arranged in positions that overlap in the axial direction with the second peripheral wall 375 and second guide wall 376 of the second flow path 372. Therefore, when forming the first carrier plate 31c from a resin molded body, it can be molded using two molds that move in the axial direction: one mold that punches out on one axial side T, and one mold that punches out on the other axial side N. This makes it easy to manufacture the first carrier plate 31c.

[0109] <Fourth Modification> Fig. 10 is an enlarged cross-sectional view of an output shaft 22d used in a planetary gear mechanism according to a fourth modified example. As shown in Fig. 10, the output shaft 22d of the fourth modified example has an inlet hole 224 instead of the inlet hole 222. In all other respects, the output shaft 22d has the same configuration as the output shaft 22. Therefore, parts of the output shaft 22d that are substantially the same as those of the output shaft 22 are given the same reference numerals, and detailed description of the same parts will be omitted.

[0110] FIG. 10 illustrates a cross-sectional view of the output shaft 22d taken along a plane perpendicular to the centerline. As shown in FIG. 10, the inlet hole 224 of the output shaft 22d extends radially outward and forward in the direction of rotation Rt. By shaping the inlet hole 224 in this manner, an inertial force acting in the opposite direction to the direction of rotation Rt acts on the lubricant CL inside the inlet hole 224 due to the rotation of the output shaft 22d, and the lubricant CL is pushed radially inward by the inertial force. This reduces the centrifugal force acting on the lubricant CL in the inlet hole 224, allowing the lubricant CL held in the holding space 54 to efficiently flow into the second internal space 221. While the inlet hole 224 illustrated in FIG. 10 extends linearly, it may also be curved.

[0111] Although the embodiments and modifications of the present invention have been described above, the configurations and their combinations in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

[0112] <Summary> The present invention has the following configuration.

[0113] (1) a motor section having a motor shaft extending along a central axis; a speed reduction mechanism that reduces the speed of rotation input from the motor shaft and outputs the reduced speed to the outside, The reduction mechanism is an input shaft rotatable about a central axis and rotated by rotation of the motor shaft; a sun gear fixed to the input shaft and rotated about the central axis; a plurality of planetary gears meshing with the sun gear; a planetary carrier that supports the plurality of planetary gears so that they can revolve around the central axis, The input shaft a hollow hole extending in the axial direction and through which a lubricant flows; a through hole that penetrates radially outward from the hollow hole and is capable of discharging the lubricant radially outward; the planetary carrier has an opposing portion that faces the through hole in the radial direction, The facing portion is a first flow path that causes the lubricant discharged from the through hole to flow to one side along the central axis; a second flow path that causes the lubricant discharged from the through hole to flow to the other side along the central axis;

[0114] (2) The first flow path has a first tapered surface whose inner diameter increases toward one axial side, the second flow path has a second tapered surface whose inner diameter increases toward the other axial side, an end portion of the first tapered surface on the other axial side and an end portion of the second tapered surface on the one axial side form a ridge portion that is continuous in the circumferential direction, The motor unit according to (1), wherein the ridge portion overlaps with the through hole in the radial direction.

[0115] (3) The first flow path has a first tapered surface whose inner diameter increases toward one axial side, the second flow path has a second tapered surface whose inner diameter increases toward the other axial side, The motor unit according to (1), wherein the first flow passages and the second flow passages are arranged alternately in the circumferential direction.

[0116] (4) A bearing is disposed on one axial side, and meshing portions of the sun gear and the planetary gears are disposed on the other axial side. The motor unit according to (3), wherein a proportion of the opposing portion in the circumferential direction occupied by the first tapered surface is larger than a proportion occupied by the second tapered surface.

[0117] (5) The opposing portion has a recess in the axial center portion that is recessed in the radial direction and continues in the circumferential direction, the first flow path has a plurality of first grooves extending from the recess toward one side in the axial direction, The motor unit according to (1), wherein the second flow path has a plurality of second grooves extending from the recess toward the other side in the axial direction.

[0118] (6) The motor unit according to (5), wherein the first groove and the second groove are offset from each other in the circumferential direction.

[0119] (7) The first flow path is a first peripheral wall protruding radially from the other axial end of the opposing portion; a first guide wall that is continuous with a rear side of the first peripheral wall in the rotation direction of the planetary carrier and that extends toward one side in the axial direction as it moves toward the rear side in the rotation direction of the planetary carrier, The second flow path is a second peripheral wall protruding radially from one axial side of the opposing portion; a second guide wall that is continuous with the rear side of the second peripheral wall in the rotation direction of the planetary carrier and that extends toward the other axial side as it moves toward the rear side in the rotation direction of the planetary carrier, The motor unit according to (1), wherein the first flow path and the second flow path are arranged side by side in the circumferential direction. [Explanation of symbols]

[0120] A Motor Unit 100 Motor section 101 Container section 102 Lid 103 Motor flange 104 Shaft through hole 10 Motor housing 11 Motor shaft 12 rotors 13 Rotor core 14 Magnet 15 Stator 16 stator core 17 coils 200 Reduction mechanism 20 Planetary gear mechanism 21 Input shaft 211 Joint 212 1st interior space 213 Through hole 22 Output shaft 221 Second interior space 222, 224 Inlet 223 Outflow hole 23 Sun Gear 24 Planetary Gear 25 Ring Gear 26 Connecting Pipe 30 Planetary Carrier 31, 31a, 31b, 31c First carrier plate 310 Inner flange 311 First shaft hole 32 Second Carrier Plate 321 Second shaft hole 322 Plate Outflow Hole 33 Planetary shaft 331 Shaft internal space 332 Planetary Bearing 333 Shaft inlet 334 Shaft Outlet Hole 34, 35, 36, 37 Opposing parts 341 First Channel 342 Second Channel 343, 353 First tapered surface 344, 354 Second tapered surface 345 Ridge 351, 361, 371 First flow path 352, 362, 372 Second flow path 360 recess 363 1st groove 364 2nd groove 373 1st peripheral wall 374 First Leading Wall 375 2nd peripheral wall 376 Second Leading Wall 40 Gear housing 401 Container section 402 Lid 403 Gear flange 404 Motor hole 41 1st supply hole 42 2nd supply hole 43 3rd supply hole 44 Discharge hole 45 Input side hole 46 Output side hole 47 Protrusion 471 1st contact surface 472 Second contact surface 50 Buffer section 511 first sealing member 512 Second sealing member 521 First fixing member 522 Second fixing member 53 External sealing member 54 Holding space 61 First bearing 62 Second bearing 63 Third bearing Ax center axis Br Motor bearing

Claims

1. a motor section having a motor shaft extending along a central axis; a speed reduction mechanism that reduces the speed of rotation input from the motor shaft and outputs the reduced speed to the outside, The reduction mechanism is an input shaft rotatable about the central axis and rotated by rotation of the motor shaft; a sun gear fixed to the input shaft and rotated about the central axis; a plurality of planetary gears meshing with the sun gear; a planetary carrier that supports the plurality of planetary gears so that they can revolve around the central axis, The input shaft a hollow hole extending in the axial direction and through which a lubricant flows; a through hole that penetrates radially outward from the hollow hole and is capable of discharging the lubricant radially outward; the planetary carrier has an opposing portion that faces the through hole in the radial direction, The facing portion is a first flow path that causes the lubricant discharged from the through hole to flow to one side along the central axis; a second flow path that causes the lubricant discharged from the through hole to flow to the other side along the central axis;

2. the first flow path has a first tapered surface whose inner diameter increases toward one axial side, the second flow path has a second tapered surface whose inner diameter increases toward the other axial side, an end portion of the first tapered surface on the other axial side and an end portion of the second tapered surface on the one axial side form a ridge portion that is continuous in the circumferential direction, The motor unit according to claim 1 , wherein the ridge portion overlaps with the through hole in the radial direction.

3. the first flow path has a first tapered surface whose inner diameter increases toward one axial side, the second flow path has a second tapered surface whose inner diameter increases toward the other axial side, The motor unit according to claim 1 , wherein the first flow passages and the second flow passages are arranged alternately in the circumferential direction.

4. A bearing is disposed on one axial side, and meshing portions of the sun gear and the planetary gears are disposed on the other axial side, 4. The motor unit according to claim 3, wherein a proportion of the opposing portion in the circumferential direction occupied by the first tapered surface is greater than a proportion of the opposing portion occupied by the second tapered surface.

5. The facing portion has a recessed portion at the axial center that is continuously recessed in the circumferential direction and in the radial direction, the first flow path has a plurality of first grooves extending from the recess toward one side in the axial direction, The motor unit according to claim 1 , wherein the second flow passage has a plurality of second grooves extending from the recess toward the other side in the axial direction.

6. The motor unit according to claim 5 , wherein the first groove and the second groove are offset from each other in the circumferential direction.

7. The first flow path is a first peripheral wall protruding in a radial direction from an end portion on the other axial side of the opposing portion; a first guide wall that is continuous with a rear side of the first peripheral wall in the rotation direction of the planetary carrier and that extends toward one side in the axial direction as it moves toward the rear side in the rotation direction of the planetary carrier, The second flow path is a second peripheral wall protruding radially from one axial side of the opposing portion; a second guide wall that is continuous with a rear side of the second peripheral wall in the rotation direction of the planetary carrier and that extends toward the other axial side as it moves toward the rear side in the rotation direction of the planetary carrier, The motor unit according to claim 1 , wherein the first flow passage and the second flow passage are arranged side by side in the circumferential direction.

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