Planetary gear device

Abstract

A planetary gear device 1 includes an internal gear 211, a sun gear 411, a plurality of planetary gears 100, a carrier 10, and a plurality of bearings 94 that facilitate rotation of the plurality of planetary gears 100 with respect to the carrier 10. The carrier 10 has a plurality of shaft-form members 5 inserted inside the plurality of bearings 94, and a first side rotor 6 and a second side rotor 7. A plurality of lubricating oil grooves 612 are formed on a surface of the first side rotor 6 oriented toward the plurality of planetary gears 100. Each of the plurality of shaft-form members 5 is formed with a shaft hole 50, a communication hole 501 via which any of the plurality of lubricating oil grooves 612 and the shaft hole 50 are allowed to communicate, and a lubricating oil supply hole 502 through which lubricating oil L is supplied from the shaft hole 50 to the bearing 94.

Description

Planetary gear unit

[0001] The present invention relates to a planetary gear device.

[0002] 2. Description of the Related Art Conventionally, a planetary gear device including a sun gear, a ring gear, planetary gears, and a carrier has been used as a reducer for reducing the rotation speed of a motor that drives a vehicle, for example.

[0003] The motor drive unit described in Patent Document 1 includes a motor as a drive source, a pair of parallel shaft gears that reduce the rotation of the motor shaft that is the output shaft of the motor, a planetary gear reduction mechanism that further reduces the rotation of the output gear shaft of the pair of parallel shaft gears, and a tire shaft to which a wheel hub shaft having a flange portion to which a tire wheel is fixed is serrated and connected.

[0004] The planetary gear reduction mechanism has a sun gear integral with the output gear shaft, multiple planetary gears meshing with the sun gear, a carrier supporting the multiple planetary gears, and a ring gear meshing with the multiple planetary gears and fixed to the reducer case. A tire shaft is formed integrally with the carrier. The rotation of the multiple planetary gears relative to the carrier is lubricated by lubricating oil contained in a reducer chamber surrounded by the motor case and the reducer case.

[0005] JP 2015-132315 A

[0006] In the planetary gear reduction mechanism of the motor drive unit described in Patent Document 1, one possible way to ensure smoother rotation of the planetary gear relative to the carrier is to place a bearing between the planetary gear and the carrier. However, with the configuration of the motor drive unit described in Patent Document 1, lubricating oil is unevenly distributed on the output gear side of the parallel shaft gear pair, which has a higher peripheral speed than the planetary gear reduction mechanism, and even if a bearing is placed between the planetary gear and the carrier, there is a risk that the bearing will not be supplied with enough lubricating oil. In particular, as the rotation speed of the carrier increases, centrifugal force makes it easier for lubricating oil to be discharged from between the planetary gear and the carrier, so it is desirable to supply more lubricating oil between the planetary gear and the carrier as the rotation speed of the carrier increases.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a planetary gear device that is capable of appropriately supplying lubricating oil to bearings disposed between the planetary gears and the carrier.

[0008] In order to achieve the above object, the present invention provides a planetary gear device comprising: an outer gear member having an internal gear; an inner gear member having a sun gear arranged inside the internal gear; a plurality of planetary gears arranged between the internal gear and the sun gear; a carrier that rotatably supports the plurality of planetary gears; and a plurality of bearings that smooth the rotation of each of the plurality of planetary gears relative to the carrier, wherein the inner gear member and the carrier are rotatable relative to the outer gear member around the central axis of the internal gear, and each of the plurality of planetary gears has an accommodating hole formed in its center to accommodate the plurality of bearings, and the carrier has a plurality of shaft-shaped members inserted inside the plurality of bearings, a first side rotor formed with a plurality of fitting holes into which one end of each of the plurality of shaft-shaped members is fitted, and and a second side rotor having a plurality of fitting holes formed therein into which the other ends of the shaft-shaped members fit, wherein the outer peripheral surfaces of the plurality of shaft-shaped members between the first side rotor and the second side rotor form bearing support surfaces that support the plurality of bearings, and a plurality of lubricating oil grooves extending from the plurality of fitting holes toward the central axis are formed in a surface of at least one of the first side rotor and the second side rotor that faces the planetary gears, and the plurality of shaft-shaped members are each formed with a shaft hole extending in the axial direction, a communication hole that connects one of the plurality of lubricating oil grooves to the shaft hole, and a lubricating oil supply hole that opens to the inner surface of the shaft hole and the bearing support surface, and lubricating oil introduced from the plurality of lubricating oil grooves into the shaft hole through the communication holes of each of the plurality of shaft-shaped members is supplied from the lubricating oil supply hole to the plurality of bearings.

[0009] According to the planetary gear device of the present invention, it is possible to appropriately supply lubricating oil to the bearings arranged between the planetary gears and the carrier.

[0010] FIG. 1 is a perspective view showing a planetary gear unit according to an embodiment of the present invention, together with a wheel to be driven and the like. FIG. 2 is a cross-sectional view of the planetary gear unit and its surroundings. FIG. 3 is a partially enlarged view of FIG. 2. FIG. 4 is a perspective cross-sectional view of a cylindrical body. FIG. 5 is a structural diagram showing an inner gear member. FIG. 6 is a structural diagram showing the surface of the cover body facing the mounting member. FIG. 7 is a cross-sectional view of the cover body taken along line A-A in FIG. 6. FIG. 8 is a perspective view of the cover body. FIG. 9 is a cross-sectional view taken along line B-B in FIG. 3. FIG. 10 is a perspective view showing a first side rotor. FIG. 11 is a perspective view showing a second side rotor and a shaft-shaped member. FIG. 12 is a plan view showing a washer. FIG. 13 is a structural diagram showing the configuration of the washer on the first side rotor side and its surroundings. FIG. 14 is a structural diagram showing the configuration of the washer on the second side rotor side and its surroundings. FIG. 15 is an explanatory diagram using multiple arrows to show the flow of lubricating oil from the lubricating oil introduction passage of the inner gear member to the hub bearing. FIG. 16 is a perspective view showing a second side rotor according to a modified example.

[0011] [Embodiments] The following describes embodiments of the present invention with reference to the drawings. The embodiments described below are shown as preferred specific examples for carrying out the present invention, and although some of the embodiments specifically exemplify various technically preferred aspects, the technical scope of the present invention is not limited to these specific embodiments.

[0012] FIG. 1 is a perspective view showing a planetary gear device 1 according to an embodiment of the present invention, a wheel 11 to be driven by the planetary gear device 1, a mounting member 12 to which the planetary gear device 1 is attached, a brake disc 13 that rotates integrally with the wheel 11, a brake device 14, and a motor 15 as a drive source. The wheel 11 has a metal wheel 111 and a rubber tire 112 attached to the wheel 111. The mounting member 12 is connected to the body of the vehicle via a suspension arm, a shock absorber, and a suspension spring. The brake device 14 generates braking force by pressing brake pads against the brake disc 13. The planetary gear device 1 decelerates the output rotation of the motor 15 and amplifies the torque to drive the wheel 11. The planetary gear device 1 and the motor 15 constitute a drive unit 1A that drives the wheel 11.

[0013] Figure 2 is a cross-sectional view of the planetary gear device 1 and its surroundings. Figure 3 is a partially enlarged view of Figure 2. In Figures 2 and 3, the top of the drawings corresponds to the top in the vertical direction, and the bottom of the drawings corresponds to the bottom in the vertical direction. In the following description, "top" and "bottom" refer to the top and bottom in the vertical direction when the planetary gear device 1 is mounted on a vehicle.

[0014] In FIG. 2, the rotation axis O of the wheel 11 １１ is indicated by a dashed line. The mounting member 12 is formed with a mounting hole 120 for mounting the planetary gear device 1. The mounting hole 120 is aligned with the rotation axis O. １１ and passes through the mounting member 12. Hereinafter, the wheel 11 side of the mounting member 12 will be referred to as the vehicle outer side, and the opposite side will be referred to as the vehicle inner side.

[0015] The motor 15 is an electric motor that generates torque to rotate a motor shaft 151 by means of a current supplied from a control unit (not shown). An output pinion gear 152 is fixed to the tip of the motor shaft 151.

[0016] The planetary gear device 1 is filled with lubricating oil L. The lubricating oil L is a base oil made of, for example, mineral oil or synthetic oil, to which additives have been added to improve and maintain lubricating performance. Bearings 91 to 96 are arranged in various parts of the planetary gear device 1, and these bearings 91 to 96 are lubricated by the lubricating oil L.

[0017] The planetary gear device 1 has a cylindrical body 2 attached to a mounting hole 120 of a mounting member 12. Fig. 4 is a perspective cross-sectional view showing the cylindrical body 2. The cylindrical body 2 has an outer gear member 21 and an outer ring member 22, which are connected together by a connecting portion 23. However, this is not limiting, and the outer gear member 21 and the outer ring member 22 may be separate members that are each fixed to the mounting member 12.

[0018] The cylindrical body 2 is restricted from axial movement and relative rotation with respect to the mounting member 12 by fixing flange pieces 221 provided on the outer ring member 22 to the mounting member 12 with bolts 121. A plurality of flange pieces 221 are radially provided on the outer ring member 22, and a bolt insertion hole 221a through which the bolt 121 is inserted is formed in each flange piece 221. The outer gear member 21 and the connecting portion 23 are disposed within the mounting hole 120. A portion of the outer ring member 22 in the axial direction, including the flange pieces 221, is disposed closer to the vehicle outer side than the mounting member 12. Note that the cylindrical body 2 may be fixed to the mounting member 12 by forming bolt insertion holes in the mounting member 12 and threaded holes in the flange pieces 221, and threading bolts inserted into the bolt insertion holes of the mounting member 12 into the threaded holes of the flange pieces 221.

[0019] An internal gear 211 having helical teeth whose tooth trace is inclined relative to the axial direction is formed on the inner periphery of the outer gear member 21. The central axis C of the internal gear 211 ２１ is the rotation axis O of the wheel 11 １１ A bearing fitting portion 212 into which a bearing 91 for supporting a carrier 10 (described later) is fitted is formed at the end of the outer gear member 21 on the vehicle inner side. The bearing 91 is a ball bearing in which a plurality of spherical rolling elements 913 are arranged between an inner ring 911 and an outer ring 912.

[0020] The planetary gear device 1 has a hub axle 8 that rotates integrally with the wheel 11 and brake disc 13, and a hub bearing 80 that is arranged between the outer ring member 22 and the hub axle 8. The hub axle 8 has a hub ring 81 that has a flange portion 811 to which the wheel 11 and brake disc 13 are fixed with a plurality of bolts 971 and nuts 972, and an inner ring member 82 that is fixed to the hub ring 81. A seal member 981 that prevents leakage of lubricating oil L is arranged between the outer ring member 22 and the hub ring 81.

[0021] The hub ring 81 has a cylindrical body portion 812 that is located inside the outer ring member 22 and is integral with a flange portion 811. The inner ring member 82 is fitted onto the end of the body portion 812 on the vehicle inner side. The hub bearing 80 has a plurality of rolling elements 800 and a cage 801 that holds the plurality of rolling elements 800, and supports the hub axle 8 rotatably with respect to the outer ring member 22. The plurality of rolling elements 800 are arranged in double rows between the outer ring member 22 and the body portion 812 of the hub ring 81, and between the outer ring member 22 and the inner ring member 82. In this embodiment, the rolling elements 800 are spherical, but the invention is not limited to this and the rolling elements 800 may be tapered rollers.

[0022] The outer ring member 22 is formed with outer raceway surfaces 22a, 22b on which a plurality of rolling elements 800 roll. The hub ring 81 is formed with an inner raceway surface 8a on which a plurality of rolling elements 800 roll inside the outer raceway surface 22a of the outer ring member 22. The inner ring member 82 is formed with an inner raceway surface 8b on which a plurality of rolling elements 800 roll inside the outer raceway surface 22b of the outer ring member 22.

[0023] The planetary gear set 1 also has a cover body 3 interposed between the mounting member 12 and the motor 15. The cover body 3 covers the opening of the mounting hole 120 of the mounting member 12 on the vehicle inner side. A motor case 153 of the motor 15 is fixed to the cover body 3 with a plurality of bolts 161. The cover body 3 is fixed to the mounting member 12 with a plurality of bolts 162 (see FIG. 1 ).

[0024] The motor shaft 151 and the output pinion gear 152 are housed in a housing hole 300 provided in the cover body 3. The rotation axis O of the motor shaft 151 １５is the central axis C of the internal gear 211 ２１ The output pinion gear 152 is supported by a bearing 92 held by the cover body 3 and a bearing 93 held by the mounting member 12. A seal member 982 is disposed between the accommodation hole 300 and the output pinion gear 152 to prevent leakage of the lubricating oil L from the accommodation hole 300.

[0025] The planetary gear device 1 also includes an outer gear member 21 having an internal gear 211, an inner gear member 4 having a sun gear 411 arranged inside the internal gear 211, a plurality of planetary gears 100 arranged between the internal gear 211 and the sun gear 411, a carrier 10 that rotatably supports the plurality of planetary gears 100, and a plurality of needle roller bearings 94 housed in each of the plurality of planetary gears 100. In this embodiment, three planetary gears 100 are arranged between the internal gear 211 and the sun gear 411.

[0026] The inner gear member 4 and the carrier 10 are aligned with the central axis C of the internal gear 211. ２１ The planetary gears 100 are rotatable relative to the outer gear member 21 around a center of rotation of the carrier 10. The planetary gears 100 are in mesh with the internal gear 211 and the sun gear 411. When the inner gear member 4 rotates relative to the outer gear member 21, the carrier 10 rotates in the same direction as the inner gear member 4, but at a slower speed than the inner gear member 4. The needle roller bearings 94 smooth the rotation of the planetary gears 100 relative to the carrier 10.

[0027] Each of the plurality of planetary gears 100 has an accommodation hole 101 formed in the center thereof to accommodate a needle roller bearing 94. As shown enlarged in Figure 3, the needle roller bearing 94 has a plurality of needle rollers 941 and a cage 942 that holds the plurality of needle rollers 941. When the planetary gear 100 rotates relative to the carrier 10, the plurality of needle rollers 941 rotate relative to the cage 942 while making contact with the cage 942. In this embodiment, two needle roller bearings 94 are arranged axially side by side in each of the accommodation holes 101 of the plurality of planetary gears 100.

[0028] 5 is a structural diagram of the inner gear member 4 as viewed in the axial direction from the outer side of the vehicle toward the inner side of the vehicle. The inner gear member 4 integrally includes a shaft portion 41 having a sun gear 411 formed on its outer periphery, a large-diameter gear portion 42 having a pitch circle diameter larger than that of the sun gear 411, and a disk portion 43 between the shaft portion 41 and the large-diameter gear portion 42. In FIG. 2, the pitch circle diameter of the sun gear 411 is P ４１１ and the pitch circle diameter of the large diameter gear portion 42 is P ４２ is shown.

[0029] The shaft portion 41 is provided closer to the vehicle outer side than the disk portion 43. The sun gear 411 is formed on the shaft portion 41 except for both axial ends thereof. The large-diameter gear portion 42 is housed in the cover body 3 and meshes with the output pinion gear 152. The disk portion 43 is formed with a plurality of through holes 431 that allow the lubricating oil L to flow in the axial direction. In this embodiment, three through holes 431 are formed at equal intervals in the circumferential direction.

[0030] The inner gear member 4 is formed with a lubricating oil introduction passage 410 for supplying lubricating oil L to a plurality of lubricating oil grooves 612 of the first side rotor 6, which will be described later. The lubricating oil introduction passage 410 is composed of an oil hole 412 formed in the center of the shaft portion 41 and a plurality of radial holes 413 that communicate with the oil hole 421 and extend in the radial direction of the shaft portion 41. The plurality of radial holes 413 open to the outer circumferential surface 41 a of the shaft portion 41 on the vehicle outer side relative to the portion where the sun gear 411 is formed. In this embodiment, two radial holes 413 are formed in the shaft portion 41.

[0031] The large diameter gear portion 42 is rotatably supported by a bearing 95 relative to the cover body 3. The pitch circle diameter P of the large diameter gear portion 42 ４２ is the pitch circle diameter P of the output pinion gear 152 １５２ When the motor 15 rotates, the inner gear member 4 rotates at a speed lower than the rotational speed of the motor 15 due to the meshing of the output pinion gear 152 and the large diameter gear portion 42.

[0032] A portion of the large diameter gear portion 42 in the circumferential direction, including the portion that meshes with the output pinion gear 152, is immersed in the lubricating oil L, and when the inner gear member 4 rotates, the lubricating oil L is scooped up by the large diameter gear portion 42. The cover body 3 has a collection structure that collects the lubricating oil L scooped up by the large diameter gear portion 42 and directs it into the lubricating oil introduction passage 410 of the inner gear member 4.

[0033] Fig. 6 is a structural diagram showing the surface of the cover body 3 on the mounting member 12 side. Fig. 7 is a cross-sectional view of the cover body 3 taken along line A-A in Fig. 6. Fig. 8 is a perspective view of the cover body 3. In Figs. 6 and 7, the shapes of holes and other components formed inside the cover body 3 are indicated by dashed lines. In Fig. 7, a portion of the inner gear member 4 is indicated by a two-dot chain line. Fig. 8 also shows the shielding plate 32 and tube 33 to be assembled to the cover body 3.

[0034] The cover body 3 is formed with a recess 30 recessed from an abutting surface 3a that abuts against the mounting member 12 toward the vehicle inner side. The cover body 3 also has an annular protrusion 31 that protrudes from a bottom surface 30a of the recess 30 toward the mounting member 12. As shown in Figure 2, a bearing 95 that supports the large-diameter gear portion 42 of the inner gear member 4 is fitted onto the outer periphery of the protrusion 31. A tip end surface 31a of the protrusion 31 faces the disk portion 43 of the inner gear member 4 in the axial direction with a small gap therebetween.

[0035] The cover body 3 also has a storage section 301 for storing lubricating oil L, a breather chamber 302 that is connected to the outside air, an air passage 303 that connects the storage section 301 and the breather chamber 302, an outside air communication hole 304 that connects the breather chamber 302 to the outside air, a collection section 305 that collects the lubricating oil L scooped up by the rotation of the inner gear member 4, and an oil passage 306 that supplies the lubricating oil L collected in the collection section 305 to an oil hole 412 of the inner gear member 4.

[0036] The reservoir 301 is provided inside the protrusion 31 and opens toward the disk portion 43 of the inner gear member 4. The plurality of through holes 431 in the disk portion 43 are formed in positions that are aligned in the axial direction and communicate with the reservoir 301 when the inner gear member 4 rotates. The breather chamber 302 is formed above the reservoir 301 and inside the protrusion 31.

[0037] The outside air communication hole 304 extends upward from the breather chamber 302 and opens to the outer surface 3b of the cover body 3. As shown in Figures 2 and 7, a breathable and waterproof filter 307 is housed in the upper end of the outside air communication hole 304. The opening of the breather chamber 302 on the side of the disk portion 43 of the inner gear member 4 is covered by a shielding plate 32.

[0038] The collection portion 305 is a notch formed to open along the rotation direction of the large diameter gear portion 42 of the inner gear member 4. In this embodiment, a pair of collection portions 305 is formed in the cover body 3 so as to efficiently collect the lubricating oil L scooped up by the rotation of the large diameter gear portion 42 in both the forward direction, which is the rotation direction of the inner gear member 4 when the vehicle is moving forward, and the reverse direction, which is the rotation direction of the inner gear member 4 when the vehicle is moving backward.

[0039] The inner surface of the recess 30 above the protrusion 31 includes a one-side inclined surface 30b that is inclined obliquely downward toward one of the collection sections 305, and a second-side inclined surface 30c that is inclined obliquely downward toward the other collection section 305. The lubricating oil L scooped up by the rotation of the large-diameter gear section 42 adheres to the one-side inclined surface 30b and flows down to one of the collection sections 305, or adheres to the other-side inclined surface 30c and flows down to the other collection section 305.

[0040] The lubricating oil L collected in the collecting portion 305 is supplied to the oil hole 412 of the inner gear member 4 through the oil passage 306. The oil passage 306 is composed of an axial hole 306a that is aligned in the axial direction with the oil hole 412 of the inner gear member 4, and a pair of radial holes 306b that respectively connect the axial hole 306a with the pair of collecting portions 305. The pair of radial holes 306b are formed from the outer surface 3b of the cover body 3 toward the axial hole 306a. The end of the axial hole 306a on the outer surface 3b side of the cover body 3 is closed by a plug 983, as shown in FIG. 8 .

[0041] As shown in Fig. 2, a portion of the tube 33 in the axial direction is inserted into the axial hole 306a. The tube 33 protrudes from the cover body 3, and its tip end is inserted into the oil hole 412 of the inner gear member 4. The tube 33 is made of, for example, metal, and is press-fitted into the axial hole 306a. However, this is not limiting, and one end of the tube 33 may be press-fitted into the oil hole 412 of the inner gear member 4, and the other end of the tube 33 may be loosely fitted into the axial hole 306a. By disposing the tube 33 between the axial hole 306a and the oil hole 412, leakage of the lubricating oil L is suppressed, and the lubricating oil L can be efficiently supplied from the oil passage 306 to the oil hole 412 of the inner gear member 4.

[0042] 2 and 3 , the carrier 10 includes a plurality of shaft-shaped members 5, first and second side rotors 6 and 7 that respectively support both ends of the shaft-shaped members 5, and a plurality of bolts 99 that fasten the first side rotor 6 and the second side rotor 7. The first side rotor 6 is formed with a plurality of fitting holes 60 into which one end of each of the shaft-shaped members 5 is fitted. The second side rotor 7 is formed with a plurality of fitting holes 70 into which the other end of each of the shaft-shaped members 5 is fitted. The plurality of planetary gears 100 are disposed between the first side rotor 6 and the second side rotor 7. The first side rotor 6 is disposed closer to the hub axle 8 and the hub bearing 80 than the second side rotor 7.

[0043] Fig. 9 is a cross-sectional view taken along line BB in Fig. 3. Fig. 10 is a perspective view showing the first side rotor 6. Fig. 11 is a perspective view showing the second side rotor 7 and the shaft-shaped member 5.

[0044] The multiple shaft-shaped members 5 are inserted inside multiple needle roller bearings 94 housed in the multiple planetary gears 100, respectively. The outer peripheral surface of each of the multiple shaft-shaped members 5 between the first side rotor 6 and the second side rotor 7 serves as a bearing support surface 5a that supports the needle roller bearing 94. When the planetary gear 100 rotates relative to the shaft-shaped members 5, the multiple needle rollers 941 of the needle roller bearing 94 roll on the bearing support surface 5a of the shaft-shaped members 5.

[0045] The shaft-shaped member 5 integrally includes a first fitting portion 51 that fits into the fitting hole 60 of the first side rotor 6, a second fitting portion 52 that fits into the fitting hole 70 of the second side rotor 7, and a large-diameter portion 53 that is disposed inside the plurality of needle roller bearings 94. The large-diameter portion 53 is formed to have a larger diameter than the first fitting portion 51 and the second fitting portion 52.

[0046] The shaft-shaped member 5 is fixed so as to be non-rotatable relative to the first side rotor 6 and the second side rotor 7. In the present embodiment, the first fitting portion 51 is press-fitted into the fitting hole 60 of the first side rotor 6, and the second fitting portion 52 is press-fitted into the fitting hole 70 of the second side rotor 7, thereby making the shaft-shaped member 5 non-rotatable relative to the first side rotor 6 and the second side rotor 7. However, this is not limiting, and the shaft-shaped member 5 may be made non-rotatable relative to the first side rotor 6 and the second side rotor 7 by, for example, crimping, welding, or using a rotation-preventing member.

[0047] 11 , the second side rotor 7 integrally includes a disk-shaped base 71, a flange 72 provided at the end of the base 71 on the vehicle inner side, and a plurality of leg shafts 73 formed to extend axially from the base 71 to protrude toward the vehicle outer side. A through hole 710 is formed in the center of the base 71, into which the shaft 41 of the inner gear member 4 is inserted. Furthermore, a plurality of shallow grooves 711, each shallower than the thickness of the base 71, are formed in the vicinity of each of the plurality of fitting holes 70. The flange 72 is formed in an annular shape protruding radially from the outer circumferential surface 71 a of the base 71, and prevents the inner ring 911 of the bearing 91 that supports the carrier 10 relative to the cylindrical body 2 from coming off.

[0048] The multiple trunnion shafts 73 are provided at equal intervals around the circumferential direction of the base 71, and the planetary gears 100 are disposed between the multiple trunnion shafts 73. A bolt insertion hole 730 is formed in each trunnion shaft 73 for inserting a bolt 99. As shown in FIG. 2 , the bolt 99 has a cylindrical insertion portion 991 that is inserted into the bolt insertion hole 730, a head portion 992 that is larger in diameter than the insertion portion 991, and a male thread portion 993 that screws into the first side rotor 6. The tip surfaces 73 a of the multiple trunnion shafts 73 abut against the first rotor end face 6 a, which is the surface of the first side rotor 6 that faces the multiple planetary gears 100.

[0049] As shown in Fig. 10 , the first side rotor 6 integrally includes a disk-shaped base 61, a splined shaft portion 62 extending from the center of the base 61 toward the vehicle outer side, and a male threaded portion 63 provided at the end portion on the vehicle outer side. As shown in Fig. 3 , the splined shaft portion 62 is spline-fitted into a splined fitting hole 810 formed in the center of the hub wheel 81. This connects the hub axle 8 and the first side rotor 6 so that torque can be transmitted. The male threaded portion 63 protrudes from the splined fitting hole 810 toward the vehicle outer side. A nut 972 is threadedly engaged with the male threaded portion 63 to prevent the splined shaft portion 62 from coming off the splined fitting hole 810.

[0050] It is also possible to eliminate the male thread portion 63 and nut 972 of the first side rotor 6 and use the bearing 91 to restrict axial movement of the carrier 10 relative to the cylindrical body 2. Even in this configuration, if the splined shaft portion 62 is spline-fitted into a spline fitting hole 810 formed in the center of the hub wheel 81 so as to be able to transmit torque, the hub axle 8 and the first side rotor 6 will be connected so as to be able to transmit torque. Furthermore, by restricting axial movement of the carrier 10 relative to the cylindrical body 2 using the bearing 91 and preventing the body portion 812 of the hub wheel 81 and the base portion 61 of the first side rotor 6 from butting against each other in the axial direction, it is possible to restrict external force input to the hub axle 8 from being applied to the carrier 10.

[0051] A recess 610 is formed in the center of the base 61 of the first side rotor 6, recessed in the axial direction toward the vehicle outer side. A bearing 96 that supports the tip end of the shaft portion 41 of the inner gear member 4 is housed in the recess 610. The bearing 96 is a ball bearing in which a plurality of spherical rolling elements 963 are arranged between an inner ring 961 and an outer ring 962. In addition, a plurality of threaded holes 611 into which male threaded portions 993 of bolts 99 are threadedly engaged are formed between the plurality of fitting holes 60 in the base 61. The plurality of fitting holes 60 and the plurality of threaded holes 611 open to the first rotor end face 6 a.

[0052] The first rotor end surface 6 a of the first side rotor 6 has a plurality of fitting holes 60 extending from the center axis C ２１ A plurality of lubricating oil grooves 612 are formed extending toward the side. In this embodiment, three lubricating oil grooves 612 are formed linearly between each of the three fitting holes 60 and the recess 610. The lubricating oil grooves 612 are recessed from the first rotor end face 6 a in the axial direction of the first side rotor 6, and the bottom surface 612 a of the lubricating oil groove 612 is located closer to the vehicle outer side than the first rotor end face 6 a.

[0053] Each of the shaft-shaped members 5 has a shaft hole 50 extending in the axial direction thereof, a communication hole 501 that connects the shaft hole 50 to one of the plurality of lubricating oil grooves 612, and a lubricating oil supply hole 502 that opens to the inner surface 50a of the shaft hole 50 and the bearing support surface 5a. ２１The lubricating oil supply hole 502 is fixed to the first side rotor 6 so that, in the radial direction of the first side rotor 6 perpendicular to the axial hole 50, the communication hole 501 is located inside the axial hole 50 and the lubricating oil supply hole 502 is located outside the axial hole 50.

[0054] The axial hole 50 is formed to extend in the axial direction from the end face of the shaft-shaped member 5 facing the first side rotor 6, and is a blind hole that does not open to the end face facing the second side rotor 7. The length of the axial hole 50 from the end face of the shaft-shaped member 5 facing the first side rotor 6 is longer than half the length of the shaft-shaped member 5. The end of the axial hole 50 facing the first side rotor 6 is closed by a plug 500.

[0055] The communication hole 501 opens toward the lubricating oil groove 612 on the outer peripheral surface 51 a of the first fitting portion 51 of the shaft-shaped member 5. The lubricating oil supply hole 502 opens at the axial center of the bearing support surface 5 a of the shaft-shaped member 5. The lubricating oil L introduced from the plurality of lubricating oil grooves 612 of the first side rotor 6 through the respective communication holes 501 of the plurality of shaft-shaped members 5 into the shaft hole 50 is supplied from the lubricating oil supply hole 502 to the plurality of needle roller bearings 94.

[0056] Additionally, the first rotor end face 6a of the first side rotor 6 is formed with a plurality of discharge grooves 613 that allow the lubricating oil L that has lubricated the plurality of needle roller bearings 94 to escape radially outward from the first side rotor 6. In this embodiment, three discharge grooves 613 are formed linearly between each of the three fitting holes 60 and the outer peripheral end of the base 61. Like the lubricating oil grooves 612, the discharge grooves 613 are recessed from the first rotor end face 6a in the axial direction of the first side rotor 6, and the bottom surfaces 613a of the discharge grooves 613 are located closer to the vehicle outer side than the first rotor end face 6a. The lubricating oil L discharged from the discharge grooves 613 is supplied to the hub bearing 80.

[0057] The lubricating oil groove 612 and the discharge groove 613 are aligned in a straight line along the radial direction of the base 61 of the first side rotor 6, and each has the same depth and width. Therefore, the lubricating oil groove 612 and the discharge groove 613 can be formed by a single cutting process using a cutting tool such as an end mill. In other words, by moving the cutting tool once between the recess 610 and the outer edge of the base 61, one lubricating oil groove 612 and one discharge groove 613 can be formed continuously.

[0058] A flat washer 90 is disposed between the base 61 of the first side rotor 6 and the plurality of planetary gears 100. A similar washer 90 is disposed between the base 71 of the second side rotor 7 and the plurality of planetary gears 100. The washer 90 on the first side rotor 6 side faces the first rotor end face 6 a in the axial direction. The washer 90 on the second side rotor 7 side faces the second rotor end face 7 a, which is the surface of the base 71 of the second side rotor 7 facing the plurality of planetary gears 100. The washer 90 on the first side rotor 6 side and the washer 90 on the second side rotor 7 side have the same shape and are common components.

[0059] Fig. 12 is a plan view showing the washer 90. Fig. 13 is a structural diagram showing the washer 90 on the first side rotor 6 side, together with the large diameter portions 53 of the multiple shaft members 5, the base portion 61 of the first side rotor 6, the multiple leg shaft portions 73 of the second side rotor 7, the shaft portion 41 of the inner gear member 4, and the insertion portions 991 of the multiple bolts 99.

[0060] The washer 90 integrally includes a plurality of sliding portions 901 having sliding surfaces 901a that slide against the shaft end faces 100a (see FIG. 3) of the plurality of planetary gears 100, and an annular portion 902 that connects the plurality of sliding portions 901 in the circumferential direction of the carrier 10. The annular portion 902 is formed in an annular shape so as to surround the outer periphery of the shaft portion 41 of the inner gear member 4. The plurality of sliding portions 901 are formed to protrude radially from the outer edge of the annular portion 902 along the radial direction of the annular portion 902, and are disposed between the plurality of leg shaft portions 73 of the second side rotor 7.

[0061] The washer 90 is formed with a plurality of insertion holes 900, through which the large diameter portions 53 of the plurality of shaft-shaped members 5 are respectively inserted. The plurality of insertion holes 900 are formed in the center of each of the plurality of sliding portions 901. The lubricating oil L that has lubricated the plurality of needle roller bearings 94 flows into the plurality of discharge grooves 613 from gaps between the inner surfaces 900a of each of the plurality of insertion holes 900 and the plurality of shaft-shaped members 5. Because the lubricating oil L that has lubricated the plurality of needle roller bearings 94 is smoothly discharged from the plurality of discharge grooves 613, even if the plurality of needle roller bearings 94 generate heat due to friction between the plurality of needle rollers 941 and the cage 942, the heat is dissipated by the lubricating oil L.

[0062] In this embodiment, each insertion hole 900 is composed of a circular portion 900b having a diameter slightly larger than the outer diameter of the large diameter portion 53 of the axial member 5, an outer protruding portion 900c formed so as to protrude further toward the opposite side of the annular portion 902 from the end of the circular portion 900b opposite the annular portion 902, and two inner protruding portions 900d formed on the annular portion 902 side of the center of the circular portion 900b.

[0063] 13, a circle C indicates the size of the receiving hole 101 of the planetary gear 100 that receives the needle roller bearing 94. １０１ is shown by a two-dot chain line. １０１ The surface of the sliding portion 901 on the planetary gear 100 side in the outer portion of the circle C is a sliding surface 901a that slides against the shaft end surface 100a of the planetary gear 100. The outer protruding portion 900c and the two inner protruding portions 900d are arranged on the circle C. １０１ The lubricating oil L that has lubricated the plurality of needle roller bearings 94 flows into the plurality of discharge grooves 613 mainly from gaps between the inner surface 900 a of the insertion hole 900 in the outer protruding portion 900 c and the plurality of shaft-shaped members 5 .

[0064] In this embodiment, the second rotor end face 7 a of the second side rotor 7 does not have grooves formed therein that correspond to the lubricating oil grooves 612 and discharge grooves 613 formed in the first rotor end face 6 a of the first side rotor 6. As a result, the lubricating oil L that has lubricated the multiple needle roller bearings 94 flows intensively into the discharge grooves 613 of the first side rotor 6, which is closer to the hub bearing 80 than the second side rotor 7, and the amount of lubricating oil L supplied to the hub bearing 80 increases.

[0065] Figure 14 is a structural diagram showing the washer 90 on the second side rotor 7 side, together with the large diameter portions 53 of the multiple shaft-shaped members 5, the base 71 and multiple leg shaft portions 73 of the second side rotor 7, the shaft portion 41 of the inner gear member 4, and the insertion portions 991 of the multiple bolts 99.

[0066] 14 , the two inward protruding portions 900d of each of the multiple insertion holes 900 in the washer 90 communicate with shallow grooves 711 formed in the base 71. The shallow grooves 711 are recesses recessed from the second rotor end face 7a in the thickness direction of the base 71, and two shallow grooves 711 are formed radially inward of each fitting hole 70 corresponding to one fitting hole 70. Each shallow groove 711 opens to a portion of the second side rotor 7 that is not partially covered by the washer 90 when viewed in the axial direction.

[0067] A portion of the lubricating oil L supplied from the lubricating oil supply hole 502 of the shaft-shaped member 5 to the needle roller bearing 94 flows toward the second side rotor 7, flows into the inward protruding portion 900d of the insertion hole 900 in the washer 90 on the second side rotor 7 side, and further flows from the inward protruding portion 900d through the shallow groove 711 into the gap between the planetary gear 100 and the base 71. The centrifugal force generated by the rotation of the second side rotor 7 causes the lubricating oil L to flow radially outward along the second rotor end surface 7a of the base 71, lubricating the bearing 91.

[0068] However, when the carrier 10 is rotating, the lubricating oil L in the accommodation hole 101 of the planetary gear 100 is unevenly distributed radially outward of the carrier 10 due to the centrifugal force caused by the rotation of the carrier 10, and therefore the lubricating oil L is less likely to flow out from the inner protruding portions 900d than from the outer protruding portions 900c of the multiple insertion holes 900 in the washer 90. For this reason, the amount of oil flowing out from the accommodation hole 101 of the planetary gear 100 to the second side rotor 7 side is less than the amount of oil flowing out to the first side rotor 6 side.

[0069] 15 is an explanatory diagram using multiple arrows to show the flow of lubricating oil L from the lubricating oil introduction passage 410 of the inner gear member 4 to the hub bearing 80. The lubricating oil L that has flowed into the oil hole 412 of the inner gear member 4 flows from the oil hole 412 to the multiple radial holes 413 due to centrifugal force generated by the rotation of the inner gear member 4, and then flows out of the shaft portion 41 from the multiple radial holes 413. The outer diameter of the shaft portion 41 is smaller than the inner diameter of the recess 610, and the lubricating oil L that has flowed out from the multiple radial holes 413 temporarily accumulates inside the recess 610.

[0070] The lubricating oil L inside the recess 610 flows into the multiple lubricating oil grooves 612 of the first side rotor 6 due to the centrifugal force generated by the rotation of the carrier 10, and then passes through the communication holes 501 of the multiple shaft-shaped members 5 that are each connected to the multiple lubricating oil grooves 612, through the axial hole 50, and reaches the lubricating oil supply hole 502, and is supplied from the lubricating oil supply hole 502 to the multiple needle roller bearings 94.

[0071] The lubricating oil L that has lubricated the multiple needle roller bearings 94 passes through the insertion holes 900 of the washer 90 and flows into the multiple discharge grooves 613, and is caused by centrifugal force to flow through the multiple discharge grooves 613 toward the outer diameter side of the base 61 of the first side rotor 6 and is released from the outer peripheral surface 61 a of the base 61. The released lubricating oil L hits the connecting portion 23 of the cylindrical body 2, and part of it flows toward the outer ring member 22 and lubricates the hub bearing 80.

[0072] Effect of the embodiment According to the present embodiment described above, the centrifugal force generated by the rotation of the inner gear member 4 and the carrier 10 causes the lubricating oil L to flow and be supplied to the plurality of needle roller bearings 94, so that an appropriate amount of lubricating oil L according to the rotational speeds of the inner gear member 4 and the carrier 10 can be supplied to the plurality of needle roller bearings 94. Furthermore, in the present embodiment, the first side rotor 6 has a plurality of discharge grooves 613 formed therein, so that the lubricating oil L that has lubricated the plurality of needle roller bearings 94 can be smoothly discharged by centrifugal force, and further the lubricating oil L discharged from the plurality of discharge grooves 613 can be supplied to the hub bearing 80.

[0073] Furthermore, according to the present embodiment, the washer 90 is disposed between the base 61 of the first side rotor 6 and the plurality of planetary gears 100, so that leakage of the lubricating oil L from the plurality of lubricating oil grooves 612 and discharge grooves 613 toward the planetary gears 100 can be suppressed, and the lubricating oil L can be smoothly flowed toward the outer periphery via the plurality of lubricating oil grooves 612 and discharge grooves 613 by centrifugal force. In other words, the washer 90 confines the lubricating oil L in the plurality of lubricating oil grooves 612 and discharge grooves 613, and the lubricating oil L inside the lubricating oil grooves 612 and discharge grooves 613 can be caused to flow toward the outer diameter side of the base 61 by centrifugal force.

[0074] Furthermore, in this embodiment, the plurality of lubricating oil grooves 612 and discharge grooves 613 are formed only in the first side rotor 6, which is closer to the hub bearing 80 than the second side rotor 7, so it is possible to increase the amount of lubricating oil L supplied to the hub bearing 80. If the lubricating oil L discharged from the plurality of discharge grooves 613 of the first side rotor 6 were not supplied to the hub bearing 80, the lubricating oil L sealed in the planetary gear set 1 would be unevenly concentrated on the vehicle inner side where the inner gear member 4, which rotates at a faster speed than the hub axle 8, is located, making the hub bearing 80 prone to poor lubrication. However, in this embodiment, the lubricating oil L discharged from the plurality of discharge grooves 613 of the first side rotor 6 is supplied to the hub bearing 80, so poor lubrication of the hub bearing 80 can be prevented.

[0075] [Modifications] In the above embodiment, a case has been described in which a plurality of lubricating oil grooves 612 and discharge grooves 613 are formed only in the first side rotor 6, but this is not limiting, and a plurality of lubricating oil grooves 712 and discharge grooves 713 may also be formed in the second rotor end surface 7a of the base portion 71 of the second side rotor 7, as shown in Fig. 16. In this case, it is preferable to also form the radial hole 413 of the inner gear member 4 and the communication hole 501 of the shaft-shaped member 5 at a position corresponding to the lubricating oil groove 712.

[0076] The plurality of lubricating oil grooves 712 extend from each of the plurality of fitting holes 70 toward the center of the base 71, and are formed linearly between the fitting holes 70 and the through-holes 710. Each lubricating oil groove 712 is recessed from the second rotor end face 7a in the axial direction of the second side rotor 7, and the bottom surface 712a of the lubricating oil groove 712 is located closer to the vehicle inner side than the second rotor end face 7a.

[0077] The plurality of discharge grooves 713 are formed linearly between each of the plurality of fitting holes 70 and the outer peripheral end of the base 71. Each discharge groove 713 is recessed from the second rotor end face 7a in the axial direction of the second side rotor 7, and the bottom surface 713a of the discharge groove 713 is located closer to the vehicle inner side than the second rotor end face 7a.

[0078] Similar to the lubricating oil grooves 612 and the discharge grooves 613 of the first side rotor 6, the multiple lubricating oil grooves 712 and the discharge grooves 713 are arranged in a straight line along the radial direction of the base 71 of the second side rotor 7, and each has the same depth and width.

[0079] When the second side rotor 7 according to this modification is used, the lubricating oil L can be supplied to the bearing 91 from the discharge groove 713 of the second side rotor 7 .

[0080] Furthermore, it is possible to omit providing either the multiple lubricant grooves 612 in the first side rotor 6 or the multiple lubricant grooves 712 in the second side rotor 7. In other words, it is possible to form multiple lubricant grooves 712 in the second side rotor 7 and not form any lubricant grooves 612 in the first side rotor 6, or to form multiple lubricant grooves 612 in the first side rotor 6 and not form any lubricant grooves 712 in the second side rotor 7.

[0081] Furthermore, it is also possible to omit providing either the multiple discharge grooves 613 in the first side rotor 6 or the multiple discharge grooves 713 in the second side rotor 7. In other words, it is also possible to form multiple discharge grooves 713 in the second side rotor 7 and not form any discharge grooves 613 in the first side rotor 6, or to form multiple discharge grooves 613 in the first side rotor 6 and not form any discharge grooves 713 in the second side rotor 7.

[0082] (Note) While the present invention has been described above based on the embodiments and modifications, these embodiments and modifications do not limit the scope of the invention as claimed. It should be noted that not all of the combinations of features described in the embodiments and modifications are necessarily essential to the means for solving the problems of the invention.

[0083] Furthermore, the present invention can be implemented by appropriately modifying it by omitting some of the components or by adding or substituting components, without departing from the spirit of the invention. For example, in the above embodiment, the planetary gear device 1 is described as being used to reduce the output rotation of the motor 15 to drive the wheels 11, but this is not limiting, and the planetary gear device of the present invention can be used for various purposes such as industrial machinery.

[0084] DESCRIPTION OF SYMBOLS 1... Planetary gear device 10... Carrier 100... Planetary gear 100a... Shaft end surface 101... Accommodation hole 21... Outer gear member 211... Internal gear 4... Inner gear member 41... Shaft portion 410... Lubricating oil introduction passage 411... Sun gear 412... Oil hole 413... Radial hole 5... Shaft-shaped member 50... Shaft hole 501... Communication hole 502... Lubricating oil supply hole 50a... Inner surface 51... First fitting portion 52... Second fitting portion 5a... Bearing support surface 6... First side rotor 60... Fitting hole 612... Lubricating oil groove 613... Discharge groove 6a... First rotor end surface 7... Second side rotor 70... Fitting hole 712... Lubricating oil groove 713... Discharge groove 7a... Second rotor end surface 8... Hub shaft 80... Hub bearing 90... Washer 900a... Inner surface 901... Sliding portion 901a... Sliding surface 902... Annular portion 94... Bearing C ２１ …Center axis L…Lubricating oil

Claims

1. A planetary gear device comprising an outer gear member having an internal gear, an inner gear member having a sun gear arranged inside the internal gear, a plurality of planetary gears arranged between the internal gear and the sun gear, a carrier rotatably supporting the plurality of planetary gears, and a plurality of bearings for smooth rotation of each of the plurality of planetary gears relative to the carrier, wherein the inner gear member and the carrier are rotatable relative to the outer gear member around the central axis of the internal gear, wherein each of the plurality of planetary gears has an accommodation hole formed in its center for accommodating the plurality of bearings, and the carrier has a plurality of shaft-shaped members inserted inside the plurality of bearings, a first side rotor formed with a plurality of fitting holes into which one end of each of the plurality of shaft-shaped members is fitted, and a second side rotor formed with a plurality of fitting holes into which the other end of each of the plurality of shaft-shaped members is fitted, a plurality of lubricating oil grooves extending from the plurality of fitting holes toward the central axis are formed in a surface of at least one of the first and second side rotors facing the planetary gears, the plurality of shaft-shaped members each having a shaft hole extending in the axial direction thereof, a communication hole connecting one of the plurality of lubricating oil grooves with the shaft hole, and a lubricating oil supply hole opening into the inner surface of the shaft hole and the bearing support surface; and a planetary gear device in which lubricating oil introduced from the plurality of lubricating oil grooves into the shaft hole through the communication holes of the plurality of shaft-shaped members is supplied from the lubricating oil supply hole to the plurality of bearings.

2. A planetary gear device according to claim 1, wherein a surface of at least one of the first side rotor and the second side rotor facing the planetary gears is formed with a plurality of discharge grooves for discharging lubricating oil that has lubricated the plurality of bearings radially outward.

3. A planetary gear device according to claim 2, wherein a washer having a plurality of insertion holes formed therein, through which the shaft-shaped members are respectively inserted, is disposed between at least one of the side rotors having the plurality of discharge grooves formed therein and the shaft end faces of the plurality of planetary gears, and wherein lubricating oil that has lubricated the plurality of bearings flows into the plurality of discharge grooves from gaps between the inner surfaces of the plurality of insertion holes of the washer and the plurality of shaft-shaped members.

4. The planetary gear device according to claim 3, wherein the washer has a plurality of sliding portions having sliding surfaces that slide against the shaft end faces of the plurality of planetary gears, and an annular portion that connects the plurality of sliding portions in the circumferential direction of the carrier.

5. A planetary gear device according to any one of claims 2 to 4, comprising a hub axle connected to the carrier so as to be able to transmit torque, and a hub bearing which rotatably supports the hub axle, and wherein lubricating oil discharged from the plurality of discharge grooves is supplied to the hub bearing.

6. The planetary gear device according to claim 5, wherein the plurality of discharge grooves are formed only in one of the first and second side rotors, which is closer to the hub bearing.

7. The planetary gear device according to claim 1, wherein the inner gear member is formed with a lubricating oil introduction passage for introducing lubricating oil into the plurality of lubricating oil grooves.

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