Transmission device

Abstract

Provided is a transmission device capable of improving the lubricity of a bearing of a planetary gear. A transmission device includes a sun gear, a planetary gear, a bearing through which a shaft portion of the planetary gear is inserted, a differential case having a bearing holding portion that holds the bearing, a differential mechanism disposed inside the differential case, and a gear case that rotatably supports the differential case. The bearing holding portion has a cylindrical portion that holds the bearing, and a groove that has an inner space recessed from a radially inner side toward a radially outer side, and that overlaps the bearing in an axial direction. The gear housing has a protruding portion that overlaps the groove of the bearing holding portion from a radially inner side and protrudes toward the bearing in an axial direction.

Description

Technical Field

[0001] The present disclosure relates to a transmission device. Background Art

[0002] In a transmission device having a differential mechanism, there is known a structure in which oil for lubrication is supplied to a bearing from a passage provided inside a shaft of a gear (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2011 / 077869 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the above-mentioned transmission device, oil can be supplied to the bearing of the gear without increasing the number of components. However, the lubricity of the bearing (ie, the supply amount of oil) has room for improvement.

[0008] One aspect of the present disclosure preferably provides a transmission device capable of improving lubricity of bearings of planetary gears.

[0009] Solutions to the problem

[0010] One scheme of the present disclosure is a transmission device, which includes: a sun gear; a ring gear, which is concentrically arranged with the sun gear; a plurality of planetary gears, which mesh with the sun gear and the ring gear; a plurality of bearings, in which shaft portions of corresponding planetary gears among the plurality of planetary gears are respectively inserted; a differential case, which has a plurality of bearing retaining portions that respectively retain the plurality of bearings; a differential mechanism, which is arranged inside the differential case; a first output shaft and a second output shaft, which are connected to the differential mechanism; and a gear case, which supports the differential case so that it can rotate.

[0011] Each of the multiple bearing retaining parts has: a cylindrical part, which retains any one of the multiple bearings; and a groove, which has an internal space recessed from the radial inner side to the radial outer side of the sun gear and overlaps with the bearing in the axial direction of the sun gear. The gear housing has a protrusion, which overlaps with the grooves of each of the multiple bearing retaining parts from the radial inner side of the sun gear and protrudes toward the multiple bearings in the axial direction of the sun gear.

[0012] According to the above configuration, the oil in the gear housing flows along the surface of the protrusion due to gravity or centrifugal force and is stored in the groove. Thus, the oil stored in the groove is supplied to the bearing. As a result, the amount of oil supplied to the bearing of the planetary gear increases, thereby improving lubricity.

[0013] In one embodiment of the present disclosure, the gear housing may have an inclined surface, which is inclined from a side of the sun gear that is farther from the bearing than the protrusion in the axial direction, and from a position that is closer to the inside than the protrusion in the radial direction of the sun gear toward the protrusion. According to the above structure, the oil in the gear housing can be guided to the protrusion through the inclined surface. As a result, the storage efficiency of the oil in the groove can be improved.

[0014] In one embodiment of the present disclosure, the gear housing may have a recessed portion, which is arranged on the back side of the protrusion located on the radial outer side of the sun gear and is recessed toward the radial inner side of the sun gear. According to the above configuration, it is possible to prevent the oil from being guided to the outside of the groove along the back side of the protrusion. As a result, it is easy for the oil to flow from the protrusion into the groove, thereby improving the storage efficiency of the oil in the groove.

[0015] In one embodiment of the present disclosure, the barrel and the groove may be an integrated structure. According to the above configuration, the hole forming process in the barrel and the groove forming process can be performed simultaneously. Therefore, it is possible to suppress the increase in manufacturing time and form a groove with high strength in the differential case. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic cross-sectional view of a transmission device according to an embodiment.

[0017] Figure 2 yes Figure 1 A schematic partial enlarged sectional view of a transmission device.

[0018] Figure 3 yes Figure 1 Schematic perspective view of the planetary gears and differential housing in the transmission.

[0019] Figure 4 yes Figure 3 A schematic perspective view of a portion of a differential housing.

[0020] Figure 5 yes Figure 3 Schematic rear view of a portion of the differential housing.

[0021] Figure 6 yes Figure 1 A schematic three-dimensional view of a portion of a gear housing in a transmission device.

[0022] Figure 7 is along Figure 1 Schematic cross-sectional view along line VII-VII in FIG.

[0023] Figure 8 yes Figure 2 A partial enlarged view of .

[0024] Fig. 9A is a schematic diagram showing a state in which the differential case is relatively rotating in a first direction. Fig. 9B It is a schematic diagram showing a state in which the differential case is relatively rotating in the second direction.

[0025] Fig.10 yes Figure 3 A schematic front view of a portion of a differential housing.

[0026] Description of symbols

[0027] 1…transmission device; 2…sun gear; 3…ring gear; 4…planetary gear;

[0028] 5…Planetary gear bearing; 6…Differential housing; 7…Differential mechanism;

[0029] 8A…1st output shaft; 8B…2nd output shaft; 9…gear housing;

[0030] 10…motor shaft; 22…enlarged diameter portion; 23…connecting hole; 61…accommodating portion;

[0031] 62 ... bracket; 63 ... bearing holding portion; 64 ... first sleeve; 65A-65D ... oil discharge groove;

[0032] 66…second sleeve; 67A-67D…oil introduction groove; 71, 72…pinion gear;

[0033] 73 ... pinion shaft; 74, 75 ... side gears; 631 ... barrel; 632 ... leg;

[0034] 633 ... groove; 661, 662 ... convex parts; 911 ... protrusion; 912 ... inclined surface;

[0035] 913…concave. DETAILED DESCRIPTION

[0036] Embodiments to which the present disclosure is applied are described below with reference to the drawings.

[0037] [1. First embodiment]

[0038] [1-1. Structure]

[0039] Figure 1 The transmission device 1 shown is provided in a vehicle and is a transmission device for transmitting power of a driving source of the vehicle to wheels.

[0040] The transmission device 1 includes a sun gear 2 , a ring gear 3 , a plurality of planetary gears 4 , a plurality of planetary gear bearings 5 ​​, a differential case 6 , a differential mechanism 7 , a first output shaft 8A, a second output shaft 8B, a gear case 9 , and a motor shaft 10 .

[0041] In the present embodiment, the axial direction of the sun gear 2 is defined as the X-axis, the vertical direction is defined as the Z-axis, and the direction perpendicular to both the X-axis and the Z-axis is defined as the Y-axis.

[0042] <Motor shaft>

[0043] The motor shaft 10 is drivingly coupled to a motor (not shown) and rotates around its own axis by the driving force of the motor.

[0044] <Sun gear>

[0045] The sun gear 2 , the ring gear 3 , and the plurality of planetary gears 4 together constitute a planetary gear mechanism (ie, a speed reduction mechanism). The sun gear 2 is disposed outside the differential case 6 and inside the gear case 9 .

[0046] The sun gear 2 is drivingly coupled to the motor shaft 10, and receives the driving force of the motor to rotate around its own axis. The rotation axis of the sun gear 2 coincides with the rotation axis of the first output shaft 8A and the second output shaft 8B.

[0047] The sun gear 2 is provided with a first sleeve 64 through which the first output shaft 8A and the differential case 6 are inserted. Figure 2 As shown, the sun gear 2 has a gear portion 21, an enlarged diameter portion 22, a plurality of communicating holes 23, and a connecting portion 24. Figure 2 Shown is located Figure 1 The upper planetary gear 4 is in a state of moving downward by orbiting.

[0048] The gear portion 21 is a cylindrical external gear meshing with a plurality of planetary gears 4. Inside the gear portion 21, the first sleeve 64 of the differential case 6 is inserted so as to provide a slight gap in the radial direction. That is, the sun gear 2 overlaps with the first sleeve 64 in the radial direction of the sun gear 2. The inner diameter of the gear portion 21 is larger than the outer diameter of the first sleeve 64.

[0049] The enlarged diameter portion 22 is a cylindrical portion provided continuously with the gear portion 21. The enlarged diameter portion 22 is connected to the end portion of the gear portion 21 located on the opposite side of the differential mechanism 7. The inner diameter D1 of the enlarged diameter portion 22 is larger than the inner diameter D2 of the outer end portion 64A of the first sleeve 64. In addition, the first sleeve 64 is not inserted into the enlarged diameter portion 22. In addition, the inner diameter D1 of the enlarged diameter portion 22 is larger than the outer diameter of the portion of the motor shaft 10 inserted into the connecting portion 24.

[0050] The plurality of connecting holes 23 each connects the opening at the outer end portion 64A of the first sleeve 64 with the space outside the sun gear 2. The plurality of connecting holes 23 are arranged to be spaced apart from each other in the circumferential direction of the expanded diameter portion 22. In the present embodiment, four connecting holes 23 are provided, and the four connecting holes 23 are arranged to be spaced 90 degrees apart from each other in the circumferential direction of the sun gear 2. However, the number of connecting holes 23 is not limited to four.

[0051] The plurality of communication holes 23 utilize gravity or centrifugal force to discharge the lubricating oil discharged from the first sleeve 64 into the planetary gear accommodation space between the differential case 6 and the gear case 9. The sun gear 2 of this embodiment serves as both a gear constituting the planetary gear mechanism and a communication member constituting a circulation path for the lubricating oil.

[0052] The connecting portion 24 is a cylindrical portion provided continuously with the enlarged diameter portion 22. The connecting portion 24 is connected to the end of the enlarged diameter portion 22 located on the opposite side of the gear portion 21. Figure 1 As shown, the end of the motor shaft 10 is spline-fitted into the connecting portion 24. The inner diameter of the connecting portion 24 is smaller than the inner diameter of the enlarged diameter portion 22.

[0053] <Ring gear>

[0054] The ring gear 3 is arranged concentrically with the sun gear 2. The ring gear 3 is fixed to the inner surface of the gear housing 9 and does not rotate relative to the gear housing 9. The ring gear 3 is an internal gear that meshes with a plurality of planetary gears 4.

[0055] <Planetary Gear>

[0056] The plurality of planetary gears 4 mesh with the sun gear 2 and the ring gear 3, respectively. The plurality of planetary gears 4 revolve around the rotation axis of the sun gear 2. In addition, although three planetary gears 4 are arranged in the present embodiment, the number of planetary gears 4 is not limited to three.

[0057] The rotation axis of each of the plurality of planetary gears 4 is parallel to the rotation axis (ie, X axis) of the sun gear 2. The plurality of planetary gears 4 are held by the differential case 6. The planetary gear 4 has a first gear portion 41, a second gear portion 42, a first shaft portion 43, and a second shaft portion 44.

[0058] The first gear portion 41 is an external gear meshing with the sun gear 2. The second gear portion 42 is an external gear meshing with the ring gear 3. The outer diameter of the second gear portion 42 is smaller than the outer diameter of the first gear portion 41. In addition, the second gear portion 42 is arranged at a position closer to the opening end 9A of the gear housing 9 than the first gear portion 41.

[0059] The first shaft portion 43 constitutes an end portion of the planetary gear 4 located on the opposite side to the opening end 9A. The first shaft portion 43 is held by the bracket 62 of the differential case 6. Specifically, the first shaft portion 43 is inserted into the ball bearing 5A held by the bracket 62.

[0060] The second shaft portion 44 constitutes an end portion of the planetary gear 4 on the side of the opening end 9A. The second shaft portion 44 is held by the differential case 6. Specifically, the second shaft portion 44 is inserted into the planetary gear bearing 5 held by the bearing holding portion 63 of the differential case 6.

[0061] <Planetary gear bearings>

[0062] The second shaft portion 44 of the corresponding planetary gear 4 is inserted through each of the plurality of planetary gear bearings 5. The planetary gear bearing 5 is not particularly limited as long as it can rotatably support the planetary gear 4, and for example, a known needle bearing is preferably used.

[0063] <Differential case>

[0064] The differential case 6 rotatably supports the plurality of planetary gears 4 and accommodates the differential mechanism 7. The differential case 6 is rotatably supported by the gear case 9. The differential case 6 rotates around the rotation axis of the sun gear 2 as the plurality of planetary gears 4 revolve.

[0065] like Figure 2 As shown, the differential case 6 has a housing portion 61, a bracket 62, a plurality of bearing retaining portions 63, a first sleeve 64, a plurality of oil discharge grooves 65A, 65B, 65C, 65D, a second sleeve 66, and a plurality of oil introduction grooves 67A, 67B, 67C, 67D.

[0066] In addition, Figure 2 In the figure, only the first oil discharge groove 65A and the third oil discharge groove 65C are shown, and Figure 4 The middle figure shows the second oil discharge groove 65B and the fourth oil discharge groove 65D. Figure 2 In the figure, only the first oil introduction groove 67A and the third oil introduction groove 67C are shown, and Figure 5 The middle figure shows the second oil introduction groove 67B and the fourth oil introduction groove 67D.

[0067] <Accommodation section>

[0068] The housing portion 61 is a main body portion of the differential case 6 and is used to house the differential mechanism 7. Figure 1 As shown, the housing portion 61 is formed by connecting a first portion 61A and a second portion 61B in a direction parallel to the X-axis.

[0069] <Bracket>

[0070] The bracket 62 is arranged so as to cover the accommodation portion 61 from the opposite side of the opening end 9A of the gear housing 9 (that is, the motor shaft 10 side). The bracket 62 is fixed to the accommodation portion 61 by a fastener such as a bolt, for example.

[0071] <Bearing holding section>

[0072] The plurality of bearing holding portions 63 respectively hold a corresponding one of the plurality of planetary gear bearings 5. Figure 3 As shown, a plurality of bearing holding portions 63 are arranged on the outer peripheral surface of the accommodation portion 61 .

[0073] The plurality of bearing holding portions 63 are arranged to be spaced apart from each other in the circumferential direction of the accommodation portion 61 (ie, in the circumferential direction of the sun gear 2 ). The bearing holding portion 63 has a cylindrical portion 631 , a leg 632 , and a groove 633 .

[0074] The cylinder 631 holds any one of the plurality of planetary bearings 5. Specifically, the planetary bearing 5 is axially inserted into the cylinder 631. The legs 632 extend radially outward from the outer peripheral surface of the housing 61 and connect the housing 61 and the cylinder 631 to each other.

[0075] The groove 633 protrudes from the end of the cylinder 631 on the opposite side of the planetary gear 4. The groove 633 has an internal space recessed from the radial inner side of the sun gear 2 toward the radial outer side (i.e., in the direction away from the rotation axis of the sun gear 2), and overlaps with the planetary gear bearing 5 in the axial direction of the sun gear 2.

[0076] That is, the groove 633 has a bottom wall intersecting with the radial direction of the sun gear 2, two side walls intersecting with the circumferential direction of the sun gear 2, and a front wall intersecting with the X-axis. The front wall covers a portion of the planetary gear bearing 5 and a portion of the barrel 631 in a direction parallel to the X-axis. Liquid can enter the internal space of the groove 633 from the radial inner side of the sun gear 2. In addition, the internal space of the groove 633 is connected to the hollow portion of the barrel 631.

[0077] As part of the first portion 61A, the plurality of bearing holding portions 63 and the accommodating portion 61 are an integrated structure. In addition, the barrel 631 and the groove 633 are an integrated structure. When the first portion 61A is processed, the groove 633 and the hole in the barrel 631 are formed at the same time. Thus, the groove 633, which is difficult to form by casting due to its small thickness, can be formed relatively easily.

[0078] <1st sleeve>

[0079] Figure 1 The first sleeve 64 shown is a cylindrical portion, and is connected to the accommodation portion 61 and the first output shaft 8A is inserted therethrough.

[0080] The first sleeve 64 extends from the housing portion 61 toward the motor shaft 10 along the X-axis. The first sleeve 64 allows the internal space of the housing portion 61 and the outside of the housing portion 61 (specifically, the internal space of the sun gear 2) to communicate with each other.

[0081] A portion of the first sleeve 64 is inserted into the sun gear 2. The central axis of the first sleeve 64 coincides with the rotation axis of the sun gear 2. In addition, the inner diameter of the first sleeve 64 is smaller than the maximum inner diameter of the accommodation portion 61.

[0082] <Oil discharge tank>

[0083] like Figure 4 As shown, the first oil discharge groove 65A, the second oil discharge groove 65B, the third oil discharge groove 65C, and the fourth oil discharge groove 65D are provided on the inner peripheral surface of the first sleeve 64 and extend from the outer end portion 64A of the first sleeve 64 to the interior of the accommodation portion 61 .

[0084] The first oil discharge groove 65A, the second oil discharge groove 65B, the third oil discharge groove 65C, and the fourth oil discharge groove 65D are arranged to be spaced apart from each other in the circumferential direction of the first sleeve 64. The shapes of the oil discharge grooves 65A to 65D will be described in detail below.

[0085] <Second sleeve>

[0086] Figure 1 The second sleeve 66 shown is a cylindrical portion, and is connected to the accommodation portion 61 and the second output shaft 8B is inserted therethrough.

[0087] The second sleeve 66 extends from the accommodation portion 61 along the X axis toward the open end 9A of the gear housing 9. The second sleeve 66 allows the internal space of the accommodation portion 61 and the outside of the accommodation portion 61 (specifically, the internal space of the gear housing 9) to communicate with each other.

[0088] The second sleeve 66 is inserted into the differential case bearing 93. The center axis of the second sleeve 66 coincides with the rotation axis of the sun gear 2. In addition, the inner diameter of the second sleeve 66 is smaller than the maximum inner diameter of the accommodation portion 61.

[0089] like Figure 3 As shown, the second sleeve 66 has a first convex portion 661 and a second convex portion 662. Both the first convex portion 661 and the second convex portion 662 protrude in the axial direction of the second side gear 75 (ie, along the X-axis) at the outer end portion 66A of the second sleeve 66 compared to other portions.

[0090] One end portion of the first protrusion 661 in the circumferential direction of the second sleeve 66 is provided at a position continuous with the first oil introduction groove 67A, and the other end portion is provided at a position continuous with the third oil introduction groove 67C.

[0091] That is, the first convex portion 661 is provided in a region between the end of the first oil introduction groove 67A and the end of the third oil introduction groove 67C in the outer end portion 66A of the second sleeve 66. The first convex portion 661 constitutes a guide for guiding oil to the first oil introduction groove 67A and the third oil introduction groove 67C.

[0092] The second convex portion 662 has a shape obtained by rotating the first convex portion 661 by 180 degrees around the rotation axis of the differential case 6. The end portion of the second convex portion 662 on one side in the circumferential direction of the second sleeve 66 is provided at a position adjacent to the second oil introduction groove 67B (see Figure 5 ) is continuous with the fourth oil introduction groove 67D (see Figure 5 ) at consecutive positions.

[0093] That is, the second convex portion 662 is provided in a region between the end of the second oil introduction groove 67B and the end of the fourth oil introduction groove 67D in the outer end portion 66A of the second sleeve 66. The second convex portion 662 constitutes a guide for guiding oil to the second oil introduction groove 67B and the fourth oil introduction groove 67D.

[0094] <Oil inlet groove>

[0095] like Figure 5 As shown, the first oil introduction groove 67A, the second oil introduction groove 67B, the third oil introduction groove 67C, and the fourth oil introduction groove 67D are provided on the inner peripheral surface of the second sleeve 66 and extend from the outer end portion 66A of the second sleeve 66 to the inside of the accommodation portion 61 .

[0096] The first oil introduction groove 67A, the second oil introduction groove 67B, the third oil introduction groove 67C, and the fourth oil introduction groove 67D are arranged to be spaced apart from each other in the circumferential direction of the second sleeve 66. The shapes of the oil introduction grooves 67A to 67D will be described in detail below.

[0097] <Differential Mechanism>

[0098] Figure 1 The differential mechanism 7 shown is a well-known mechanism, and the differential mechanism 7 causes the first output shaft 8A and the second output shaft 8B to perform differential rotation, and distributes the rotation of the differential case 6 to the first output shaft 8A and the second output shaft 8B.

[0099] The differential mechanism 7 includes a first pinion gear 71 and a second pinion gear 72 (see Figure 5), the pinion shaft 73, the first side gear 74, and the second side gear 75. The differential mechanism 7 is arranged inside the differential case 6. Specifically, the first pinion 71, the second pinion 72, the pinion shaft 73, the first side gear 74, and the second side gear 75 are accommodated in the accommodating portion 61 of the differential case 6.

[0100] <Pinion gear and pinion shaft>

[0101] like Figure 5 As shown, the first pinion gear 71 and the second pinion gear 72 are bevel gears each having a rotation axis orthogonal to the rotation axis of the sun gear 2 (ie, the X-axis).

[0102] The rotation axis of the first pinion 71 coincides with the rotation axis of the second pinion 72. The first pinion 71 and the second pinion 72 are disposed so as to face each other. The first pinion 71 and the second pinion 72 have the same shape and are in a mirror image relationship with each other.

[0103] The pinion shaft 73 supports the first pinion 71 and the second pinion 72 so that they can rotate. The central axis (i.e., the longitudinal direction) of the pinion shaft 73 is orthogonal to the X-axis. The pinion shaft 73 is fixed to the housing 61 and does not rotate relative to the differential case 6. That is, the pinion shaft 73 rotates together with the housing 61 around the rotation axis of the sun gear 2.

[0104] <Side gear>

[0105] like Figure 1 As shown, the first side gear 74 and the second side gear 75 are bevel gears each having a rotation axis that coincides with the rotation axis of the sun gear 2 (ie, the X-axis).

[0106] The rotation axis of the first side gear 74 coincides with the rotation axis of the second side gear 75. The first side gear 74 and the second side gear 75 are disposed so as to face each other.

[0107] The first side gear 74 is disposed along the X-axis at a position closer to the motor shaft 10 than the second side gear 75. The first side gear 74 and the second side gear 75 have the same shape and are in a mirror image relationship with each other.

[0108] The first side gear 74 and the second side gear 75 are both rotatably held by the accommodation portion 61. The first side gear 74 meshes with the first pinion gear 71 and the second pinion gear 72, and is connected to the first output shaft 8A. The second side gear 75 meshes with the first pinion gear 71 and the second pinion gear 72, and is connected to the second output shaft 8B.

[0109] The first side gear 74 and the second side gear 75 rotate together with the differential case 6 , and rotate relatively with respect to the differential case 6 by the rotation transmitted from the first pinion gear 71 and the second pinion gear 72 .

[0110] <Output shaft>

[0111] The first output shaft 8A and the second output shaft 8B are spline-fitted to the first side gear 74 or the second side gear 75 , respectively.

[0112] The first output shaft 8A and the second output shaft 8B each output rotation to the wheels of the vehicle. The first output shaft 8A and the second output shaft 8B are differentially rotated by the connected differential mechanism 7, and rotate according to the rotation direction of the motor shaft 10 (that is, the rotation direction of the differential case 6).

[0113] <Gear Housing>

[0114] The gear housing 9 accommodates the sun gear 2 , the ring gear 3 , and the plurality of planetary gears 4 , and rotatably supports the differential case 6 .

[0115] The gear housing 9 includes a first body 91, a second body 92, a differential case bearing 93, and an oil guide 94. The first body 91 and the second body 92 are connected to each other to form a planetary gear accommodation space for accommodating each gear and the differential case 6. In addition, a motor (not shown) serving as a drive source is arranged inside the second body 92.

[0116] The first body 91 has an open end 9A into which the second output shaft 8B is inserted. Lubricating oil for lubricating the gears and shafts is stored in the planetary gear accommodation space of the gear housing 9. The planetary gear accommodation space is sealed by a sealing member or the like.

[0117] The differential case bearing 93 rotatably supports the differential case 6. Specifically, the second sleeve 66 of the differential case 6 is inserted through the differential case bearing 93. The differential case bearing 93 is held by the first body 91. The differential case bearing 93 is a sealed bearing, and the lubricating oil supplied from the oil guide 94 can pass through the sealed bearing.

[0118] Figure 6 and Figure 7 The oil guide 94 shown is a groove-shaped flow path arranged in the planetary gear accommodating space. The inlet 941 of the oil guide 94 is arranged at a position above the rotation axis of the sun gear 2 and arranged radially outside the orbit of the multiple planetary gears 4. In addition, the inlet 941 is arranged at a position overlapping with the first gear part 41 of the multiple planetary gears 4 in the radial direction of the sun gear 2.

[0119] In addition, Figure 7In the embodiment, when the car moves forward, the sun gear 2 and the differential case 6 rotate clockwise, and the plurality of planetary gears 4 rotate counterclockwise while revolving clockwise. When the car moves backward, the rotation direction of each component is opposite to the above direction.

[0120] The lubricating oil stored below the planetary gear accommodation space is scooped up by the orbiting planetary gear 4 and drips into the inlet 941 . Thus, the lubricating oil is supplied into the oil guide 94 .

[0121] The outlet 942 of the oil guide 94 is arranged below the inlet 941 and is arranged near the upper end of the outer end portion 66A of the second sleeve 66 of the differential case 6 (see Figure 1 The lubricating oil supplied from the inlet 941 to the oil guide 94 slides down inside the oil guide 94 and is supplied to the vicinity of the second sleeve 66 .

[0122] like Figure 2 As shown by the arrow in , the lubricating oil supplied to the vicinity of the second sleeve 66 passes through the second sleeve 66 and is supplied to the interior of the accommodating portion 61. This lubricates the differential mechanism 7. The lubricating oil in the differential mechanism 7 passes through the first sleeve 64 and is discharged to the interior of the sun gear 2 (i.e., the connecting member).

[0123] The lubricating oil discharged into the interior of the sun gear 2 is discharged from the connecting hole 23 into the planetary gear accommodating space and is stored again in the lower part of the planetary gear accommodating space. As described above, the lubricating oil stored in the planetary gear accommodating space is supplied to the oil guide 94 through the planetary gear 4. Thus, the lubricating oil circulates in the gear housing 9.

[0124] Furthermore, a portion of the lubricating oil supplied to the vicinity of the second sleeve 66 is not supplied to the accommodating portion 61, but passes through the shield of the differential case bearing 93 and slides below the second sleeve 66 and the accommodating portion 61, thereby being stored in the lower portion of the planetary gear accommodating space.

[0125] <Supplying Lubricating Oil to Planetary Gear Bearings>

[0126] like Figure 8 As shown in FIG. 1 , a part of the lubricating oil is supplied to the planetary gear bearing 5 along the inner peripheral surface of the first main body 91 of the gear housing 9. The flow of the lubricating oil will be described in detail below.

[0127] The first body 91 of the gear housing 9 has a protrusion 911, an inclined surface 912, and a recess 913. The protrusion 911 overlaps with the grooves 633 of the bearing holders 63 from the radial inside of the sun gear 2 and protrudes toward the planetary bearings 5 ​​in the axial direction of the sun gear.

[0128] That is, the protrusion 911 is a portion protruding from the inner surface of the first body 91 in a manner covering a portion of the opening of the groove 633. The protrusion 911 is located radially inward of the sun gear 2 relative to the rotation axis L of the planetary gear 4 (i.e., the central axis of the planetary gear bearing 5).

[0129] In the present embodiment, the protrusion 911 is formed into a circular ring shape when viewed from the axial direction of the sun gear 2. That is, the protrusion 911 is provided on the entire circumference of the first body 91. However, the protrusion 911 may be provided only on the lower portion of the first body 91 (for example, a portion below the rotation axis of the sun gear 2).

[0130] The inclined surface 912 is inclined toward the protrusion 911 from a side farther from the planetary bearing 5 than the protrusion 911 in the axial direction of the sun gear 2 and from a position inside the protrusion 911 in the radial direction of the sun gear 2 .

[0131] That is, the inclined surface 912 is formed by a portion of the inner surface of the first body 91 that extends from the protrusion 911 toward the opening end 9A. The inclined surface 912 may be formed by a flat surface, a curved surface, or a bent surface.

[0132] The recess 913 is arranged on the back surface of the protrusion 911 located on the radial outer side of the sun gear 2 (i.e., the surface on the side opposite to the inclined surface 912), and is a portion recessed toward the radial inner side of the sun gear 2. The recess 913 is a groove extending along the circumference of the sun gear 2. The recess 913 can be provided on the entire circumference of the first body 91, or only on the lower part of the first body 91 (for example, the part where the lubricating oil that has entered the recess 913 falls).

[0133] The lubricating oil passes through the shield of the differential case bearing 93 via the oil guide 94 and flows to the lower side of the second sleeve 66, or the lubricating oil directly reaches the inclined surface 912 by scattering in the gear case 9 without passing through the oil guide 94, such as Figure 8 As shown by the arrow in , the lubricating oil flows along the inclined surface 912 toward the protrusion 911. The lubricating oil reaching the protrusion 911 falls downward from the front end of the protrusion 911 and is collected inside the groove 633.

[0134] Furthermore, the lubricating oil flowing from the front end of the protrusion 911 to the back side of the protrusion 911 escapes from the back side of the protrusion 911 through the recess 913. Therefore, the lubricating oil can be prevented from flowing along the inner surface of the first body 91 to the bottom of the concave groove 633.

[0135] <Shapes of Oil Supply Groove and Oil Discharge Groove>

[0136] like Figure 5As shown in FIG. 1 , when the oil introduction grooves 67A to 67D are respectively viewed from the axial direction of the second side gear 75 (i.e., the direction parallel to the X-axis), the oil introduction grooves 67A to 67D reach the internal space of the accommodation portion 61 at a position closer to the radially outer side of the second side gear 75 than the second side gear 75. Each outlet end of the oil introduction grooves 67A to 67D has a portion that does not overlap with the rotating second side gear 75.

[0137] Furthermore, when viewed from the axial direction of the second side gear 75 , the oil introduction grooves 67A to 67D are arranged so as not to overlap with either the first pinion gear 71 or the second pinion gear 72 .

[0138] The first oil introduction groove 67A and the second oil introduction groove 67B are arranged side by side between the first pinion 71 and the second pinion 72 in the circumferential direction of the second side gear 75. The second oil introduction groove 67B has a shape symmetrical to the first oil introduction groove 67A with respect to a virtual plane orthogonal to the Y axis.

[0139] The third oil introduction groove 67C and the fourth oil introduction groove 67D are symmetrically symmetrical with the first oil introduction groove 67A and the second oil introduction groove 67B with respect to a virtual plane orthogonal to the Z axis. That is, the third oil introduction groove 67C and the fourth oil introduction groove 67D are arranged on the opposite side of the first oil introduction groove 67A and the second oil introduction groove 67B across the pinion shaft 73, and the third oil introduction groove 67C and the fourth oil introduction groove 67D are arranged side by side between the first pinion 71 and the second pinion 72 in the circumferential direction of the second side gear 75.

[0140] Each of the oil introduction grooves 67A-67D extends in a straight line. That is, in the oil introduction grooves 67A-67D, the line connecting the center points in the width direction of the groove is a straight line. In addition, the oil introduction grooves 67A-67D gradually widen toward the housing portion 61. That is, the width of the oil introduction grooves 67A-67D is the smallest at the outer end portion 66A of the second sleeve 66, and the largest inside the housing portion 61.

[0141] like Fig. 9A and Fig. 9B As shown, the first protrusion 661 and the second protrusion 662 of the second sleeve 66 clamp the first oil inlet groove 67A and the second oil inlet groove 67B in the circumferential direction of the second side gear 75 (i.e., the circumferential direction of the second sleeve 66), and clamp the third oil inlet groove 67C and the fourth oil inlet groove 67D in other areas.

[0142] Specifically, the ends of the first oil guide groove 67A and the second oil guide groove 67B are arranged in a region sandwiched by the first end 661A of the first convex portion 661 and the first end 662A of the second convex portion 662. The ends of the third oil introduction groove 67C and the fourth oil introduction groove 67D are arranged in a region sandwiched by the second end 661B of the first convex portion 661 and the second end 662B of the second convex portion 662.

[0143] like Fig. 9A As shown, when the differential case 6 rotates relative to the second output shaft 8B in the first direction R1, the lubricating oil O in the planetary gear accommodation space collides with the first end 661A of the first convex portion 661, and the lubricating oil O is guided to the first oil introduction groove 67A. Alternatively, the lubricating oil O collides with the second end 662B of the second convex portion 662, and the lubricating oil O is guided to the fourth oil introduction groove 67D.

[0144] like Fig. 9B As shown, when the differential case 6 rotates relative to the second output shaft 8B in the second direction R2 opposite to the first direction R1, the lubricating oil O in the planetary gear accommodation space collides with the second end 661B of the first convex portion 661, and the lubricating oil O is guided to the third oil introduction groove 67C. Alternatively, the lubricating oil O collides with the first end 662A of the second convex portion 662, and the lubricating oil O is guided to the second oil introduction groove 67B.

[0145] like Fig.10 As shown in FIG. 1 , when the oil discharge grooves 65A to 65D are respectively observed from the axial direction of the first side gear 74 (i.e., the direction parallel to the X-axis), the oil discharge grooves 65A to 65D reach the internal space of the accommodation portion 61 at a position closer to the radially outer side of the first side gear 74 than the first side gear 74. Each outlet end of the oil discharge grooves 65A to 65D has a portion that does not overlap with the rotating first side gear 74.

[0146] in addition, Fig.10 This is a diagram showing the interior of the accommodation portion 61 as viewed from the second sleeve 66 side, and illustration of the first pinion gear 71 , the second pinion gear 72 , the pinion shaft 73 , and the second side gear 75 is omitted.

[0147] When the oil discharge grooves 65A-65D are respectively viewed from the axial direction of the first side gear 74, the oil discharge grooves 65A-65D are arranged at positions overlapping with the first pinion gear 71 or the second pinion gear 72. Furthermore, when the oil discharge grooves 65A-65D are respectively viewed from the axial direction of the first side gear 74, they are arranged between any two of the oil introduction grooves 67A-67D in the circumferential direction of the first side gear 74.

[0148] like Figure 4As shown, the oil discharge grooves 65A-65D each extend in a straight line. In addition, the oil discharge grooves 65A-65D gradually widen toward the outer end 64A of the first sleeve 64. In other words, the width of the oil introduction grooves 67A-67D is the smallest in the accommodating portion 61 and the largest inside the outer end 64A of the first sleeve 64.

[0149] [1-2. Effect]

[0150] According to the embodiments described in detail above, the following effects can be obtained.

[0151] (1a) The oil in the gear housing 9 flows along the surface of the protrusion 911 due to gravity or centrifugal force, and is stored in the groove 633. Thus, the oil stored in the groove 633 is supplied to the planetary gear bearing 5. As a result, the amount of oil supplied to the planetary gear bearing 5 increases, so that lubricity can be improved.

[0152] (1b) The oil in the gear housing 9 can be guided to the protrusion 911 by the inclined surface 912. As a result, the storage efficiency of the oil in the groove 633 can be improved.

[0153] (1c) The recessed portion 913 can prevent the oil from being guided to the outside of the groove 633 along the back surface of the protrusion 911. As a result, the oil can easily fall from the protrusion 911 into the groove 633, thereby improving the storage efficiency of the oil in the groove 633.

[0154] (1d) Since the cylindrical portion 631 and the groove 633 are integrally structured, the hole forming process in the cylindrical portion 631 and the groove 633 can be simultaneously performed. Therefore, the groove 633 having high strength can be formed in the differential case 6 while suppressing an increase in manufacturing man-hours.

[0155] [2. Other embodiments]

[0156] The embodiments of the present disclosure are described above, but the present disclosure is not limited to the above embodiments and can take various forms.

[0157] (2a) In the transmission device of the above embodiment, the gear housing may not have an inclined surface and a recessed portion.

[0158] (2b) In the transmission device of the above embodiment, the groove of the differential case may not be an integrated structure with the barrel. For example, the groove may be fixed to the barrel by welding, fastening, etc. In addition, the differential case may have a circular groove arranged to span across multiple barrels. In other words, the multiple grooves may be connected to each other in the circumferential direction of the sun gear.

[0159] (2c) The functions of one component in the above-mentioned embodiment may be shared by multiple components, or the functions of multiple components may be integrated into one component. In addition, a part of the structure of the above-mentioned embodiment may be omitted. In addition, at least a part of the structure of the above-mentioned embodiment may be added to the structure of the above-mentioned other embodiment, or at least a part of the structure of the above-mentioned embodiment may be replaced with the structure of the above-mentioned other embodiment, etc. In addition, all the methods included in the technical idea determined by the sentences recorded in the claims are embodiments of the present disclosure.

Claims

1. A transmission device, characterized in that: have: Sun gear; a ring gear, the ring gear being arranged concentrically with the sun gear; a plurality of planetary gears meshing with the sun gear and the ring gear; a plurality of bearings, wherein the shafts of the plurality of planetary gears are respectively inserted through the plurality of bearings; a differential case having a plurality of bearing holding portions for respectively holding the plurality of bearings; a differential mechanism, the differential mechanism being arranged inside the differential housing; a first output shaft and a second output shaft, wherein the first output shaft and the second output shaft are connected to the differential mechanism; and a gear housing that rotatably supports the differential housing, and Each of the plurality of bearing holding portions has: a cylindrical portion that holds any one of the plurality of bearings; and a groove having an inner space recessed from the radial inner side toward the radial outer side of the sun gear and overlapping with the bearing in the axial direction of the sun gear, The gear housing has a protrusion that overlaps with the respective grooves of the plurality of bearing holding portions from the radially inner side of the sun gear and protrudes toward the plurality of bearings in the axial direction of the sun gear.

2. The transmission device according to claim 1, characterized in that: The gear housing has an inclined surface that is inclined toward the protrusion from a side farther from the bearing than the protrusion in the axial direction of the sun gear and from a position inside the protrusion in the radial direction of the sun gear.

3. The transmission device according to claim 1 or 2, characterized in that: The gear housing has a recessed portion that is disposed on a back surface of the protruding portion on the radially outer side of the sun gear and is recessed toward the radially inner side of the sun gear.

4. The transmission device according to claim 1 or 2, characterized in that: The barrel and the groove are an integrated structure.

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