Transmission

Abstract

The present disclosure provides a transmission device that can increase lubricity of a differential mechanism without using a pump. The present disclosure is a transmission device comprising a differential case and a differential mechanism that is disposed inside the differential case. The differential mechanism has a first pinion gear, a second pinion gear, a first side gear, and a second side gear. The differential case has an accommodation part, a first sleeve that is connected to the accommodation part, a second sleeve that is connected to the accommodation part, an oil discharge groove that extends from an outer end part of the first sleeve to the inside of the accommodation part, and an oil introduction groove that extends from an outer end part of the second sleeve to the inside of the accommodation part. The oil introduction groove reaches an internal space of the accommodation part on a side further radially outward than the second side gear, and is disposed so as to overlap with neither the first pinion gear nor the second pinion gear.

Description

[Technical field]

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

[0002] 2. Description of the Related Art In a transmission device having a differential mechanism, a configuration is known in which lubricating oil is supplied to the differential mechanism by using a pump (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-174582 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned transmission requires a pump for supplying oil, which complicates the structure of the device, and there is a risk that the supply of oil may be hindered by the rotation of the gears constituting the differential mechanism.

[0005] One aspect of the present disclosure preferably provides a transmission that can increase lubrication of a differential mechanism without using a pump. [Means for solving the problem]

[0006] One aspect of the present disclosure is a transmission device comprising a sun gear, a ring gear arranged concentrically with the sun gear, a plurality of planetary gears meshing with the sun gear and the ring gear, a differential case that rotatably supports the plurality of planetary gears, a differential mechanism arranged inside the differential case, a first output shaft and a second output shaft connected to the differential mechanism, and a gear case that rotatably supports the differential case.

[0007] The differential mechanism has a first pinion gear and a second pinion gear that face each other and have a rotation axis perpendicular to the rotation axis of the sun gear, and a first side gear and a second side gear that face each other and have a rotation axis coinciding with the rotation axis of the sun gear. The first side gear meshes with the first pinion gear and the second pinion gear and is connected to the first output shaft. The second side gear meshes with the first pinion gear and the second pinion gear and is connected to the second output shaft.

[0008] The differential case has an accommodating portion that accommodates the first pinion gear, the second pinion gear, the first side gear, and the second side gear, a first sleeve connected to the accommodating portion and through which the first output shaft is inserted, a second sleeve connected to the accommodating portion and through which the second output shaft is inserted, at least one oil discharge groove provided on the inner surface of the first sleeve and extending from the outer end of the first sleeve to the inside of the accommodating portion, and at least one oil introduction groove provided on the inner surface of the second sleeve and extending from the outer end of the second sleeve to the inside of the accommodating portion.

[0009] At least one oil introduction groove reaches the internal space of the accommodating portion radially outside the second side gear when viewed from the axial direction of the second side gear, and is positioned so as not to overlap with both the first pinion gear and the second pinion gear.

[0010] According to this configuration, the oil inlet groove and the oil outlet groove form a circulation path for oil that lubricates the differential mechanism within the housing. In addition, the oil inlet groove is arranged so as not to overlap with the pinion gear, which suppresses the interruption of the supply of oil to the housing due to the rotation of the pinion gear. As a result, the lubrication of the differential mechanism can be improved without using a pump.

[0011] In one aspect of the present disclosure, the differential case may have, as at least one oil inlet groove, a first oil inlet groove and a second oil inlet groove arranged side by side between the first pinion gear and the second pinion gear in the circumferential direction of the second side gear. The second sleeve may have a first convex portion and a second convex portion protruding in the axial direction of the second side gear at an outer end portion. The first convex portion and the second convex portion may be arranged to sandwich the first oil inlet groove and the second oil inlet groove in the circumferential direction of the second side gear.

[0012] According to this configuration, when the differential case rotates in a first direction relative to the second output shaft (for example, when the rotation speed of the second output shaft is higher than the rotation speed of the differential case), the first convex portion guides the oil to the first oil introduction groove, and when the differential case rotates in a second direction opposite to the first direction relative to the second output shaft (for example, when the rotation speed of the second output shaft is lower than the rotation speed of the differential case), the second convex portion guides the oil to the second oil introduction groove. Therefore, regardless of the speed and direction of rotation of the second output shaft, oil can be efficiently supplied to the differential mechanism.

[0013] In one aspect of the present disclosure, the first oil inlet groove and the second oil inlet groove may extend linearly and widen toward the housing. With this configuration, the linear oil inlet grooves suppress changes in oil supply efficiency depending on the rotation direction of the differential case. In addition, the widening of the oil inlet grooves allows oil to be efficiently supplied to the differential mechanism by centrifugal force accompanying the rotation of the differential case. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of a transmission device according to an embodiment. [Diagram 2] FIG. 2 is a schematic enlarged partial cross-sectional view of the transmission device of FIG. [Diagram 3] FIG. 3 is a schematic perspective view of a planetary gear and a differential case in the transmission device of FIG. [Figure 4] FIG. 4 is a schematic perspective view of a portion of the differential case of FIG. [Diagram 5] FIG. 5 is a schematic rear view of a portion of the differential case of FIG. [Figure 6] FIG. 6 is a schematic perspective view of a portion of a gear case in the transmission device of FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a partially enlarged view of FIG. [Figure 9] FIG. 9A is a schematic diagram showing a state in which the differential case relatively rotates in a first direction, and FIG. 9B is a schematic diagram showing a state in which the differential case relatively rotates in a second direction. [Figure 10] FIG. 10 is a schematic front view of a portion of the differential case of FIG. [Explanation of symbols]

[0015] 1... transmission device, 2... sun gear, 3... ring gear, 4... planetary gear, 5...planetary gear bearing, 6...differential case, 7...differential mechanism, 8A...first output shaft, 8B...second output shaft, 9...gear case, 10...motor shaft, 22...expanded diameter portion, 23...communication hole, 61...accommodating portion, 62 ... carrier, 63 ... bearing holder, 64 ... first sleeve, 65A-65D…Oil drain groove, 66…Second sleeve, 67A-67D...Oil inlet groove, 71, 72...Pinion gear, 73... pinion shaft, 74, 75... side gears, 631... cylindrical portion, 632...leg portion, 633...pocket, 661, 662...projection portion, 911...protrusion, 912...inclined surface, 913...recess. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.

[0017] [1. First embodiment] [1-1. Configuration] A transmission device 1 shown in FIG. 1 is a device that is installed in an automobile and transmits the power of a drive source of the automobile to the wheels.

[0018] 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.

[0019] In this 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.

[0020] <Motor shaft> The motor shaft 10 is drivingly connected to a motor (not shown) and is axially rotated by the driving force of the motor.

[0021] <Sun gear> The sun gear 2 constitutes a planetary gear mechanism (that is, a reduction mechanism) together with the ring gear 3 and a plurality of planetary gears 4. The sun gear 2 is disposed outside the differential case 6 and inside the gear case 9.

[0022] The sun gear 2 is axially rotated by the driving force of the motor by being drivingly connected to the motor shaft 10. 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.

[0023] The first output shaft 8A and the first sleeve 64 of the differential case 6 are inserted into the sun gear 2. As shown in Fig. 2, the sun gear 2 has a gear portion 21, an enlarged diameter portion 22, a plurality of communication holes 23, and a connecting portion 24. Note that Fig. 2 shows a state in which the planetary gear 4 located at the upper part of Fig. 1 has moved downward due to revolution.

[0024] The gear portion 21 is a cylindrical external gear that meshes with the multiple planetary gears 4. The first sleeve 64 of the differential case 6 is inserted into the inside of the gear portion 21 so that a small gap is provided in the radial direction. In other words, 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.

[0025] 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 of the gear portion 21 opposite to 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. The first sleeve 64 is not inserted into the enlarged diameter portion 22. The inner diameter D1 of the enlarged diameter portion 22 is also larger than the outer diameter of the portion of the motor shaft 10 inserted into the connecting portion 24.

[0026] Each of the multiple communication holes 23 communicates between an opening at the outer end portion 64A of the first sleeve 64 and a space outside the sun gear 2. The multiple communication holes 23 are arranged spaced apart from one another in the circumferential direction of the expanded diameter portion 22. In this embodiment, four communication holes 23 are provided, spaced apart by 90° in the circumferential direction of the sun gear 2. However, the number of communication holes 23 is not limited to four.

[0027] The plurality of communication holes 23 discharge the lubricating oil discharged from the first sleeve 64 by gravity or centrifugal force into the planetary gear accommodating space between the differential case 6 and the gear case 9. The sun gear 2 of the present embodiment serves both as a gear constituting the planetary gear mechanism and as a communication member constituting a circulation path for the lubricating oil.

[0028] 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 opposite to the gear portion 21. As shown in FIG. 1, 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.

[0029] <Ring gear> The ring gear 3 is disposed concentrically with the sun gear 2. The ring gear 3 is fixed to the inner surface of a gear case 9 and does not rotate relative to the gear case 9. The ring gear 3 is an internal gear with which a plurality of planetary gears 4 mesh.

[0030] <Planetary gear> The multiple planetary gears 4 are each meshed with the sun gear 2 and the ring gear 3. The multiple planetary gears 4 revolve around the rotation axis of the sun gear 2. In this embodiment, three planetary gears 4 are arranged, but the number of planetary gears 4 is not limited to three.

[0031] The rotation axis of each of the multiple planetary gears 4 is parallel to the rotation axis of the sun gear 2 (i.e., the X-axis). The multiple planetary gears 4 are held in a 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.

[0032] The first gear portion 41 is an external gear that meshes with the sun gear 2. The second gear portion 42 is an external gear that meshes 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 disposed closer to the open end 9A of the gear case 9 than the first gear portion 41.

[0033] The first shaft portion 43 constitutes an end portion opposite to the open end 9A of the planetary gear 4. The first shaft portion 43 is held by a carrier 62 of the differential case 6. Specifically, the first shaft portion 43 is inserted into a ball bearing 5A held by the carrier 62.

[0034] The second shaft portion 44 constitutes an end portion of the planetary gear 4 that is closer to the open 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.

[0035] <Planetary gear bearing> The second shaft portions 44 of the planetary gears 4 are inserted into the planetary gear bearings 5 ​​one by one. The planetary gear bearings 5 ​​are not particularly limited as long as they can rotatably support the planetary gears 4, but for example, known needle bearings are suitable.

[0036] <Differential case> The differential case 6 rotatably supports the plurality of planetary gears 4 and houses a differential mechanism 7. The differential case 6 is rotatably supported by a 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.

[0037] As shown in FIG. 2, the differential case 6 has an accommodating portion 61, a carrier 62, a plurality of bearing holding 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.

[0038] Note that only the first oil discharge groove 65A and the third oil discharge groove 65C are shown in Fig. 2, and the second oil discharge groove 65B and the fourth oil discharge groove 65D are shown in Fig. 4. Similarly, only the first oil inlet groove 67A and the third oil inlet groove 67C are shown in Fig. 2, and the second oil inlet groove 67B and the fourth oil inlet groove 67D are shown in Fig. 5.

[0039] <Containment Unit> The accommodation portion 61 is a main body portion of the differential case 6, and accommodates the differential mechanism 7. As shown in Fig. 1, the accommodation portion 61 is configured by connecting a first part 61A and a second part 61B in a direction parallel to the X-axis.

[0040] <Career> The carrier 62 is disposed so as to cover the accommodation portion 61 from the side opposite to the open end 9A of the gear case 9 (i.e., the motor shaft 10 side). The carrier 62 is fixed to the accommodation portion 61 by a fastener such as a bolt.

[0041] <Bearing holder> Each of the plurality of bearing holders 63 holds one of the plurality of planetary gear bearings 5. As shown in FIG.

[0042] The bearing holding portions 63 are disposed apart from one another in the circumferential direction of the accommodating portion 61 (that is, in the circumferential direction of the sun gear 2).

[0043] The cylindrical portion 631 holds one of the plurality of planetary gear bearings 5. Specifically, the planetary gear bearing 5 is axially inserted into the cylindrical portion 631. The leg portions 632 extend radially outward from the outer circumferential surface of the housing portion 61 and connect the housing portion 61 and the cylindrical portion 631 to each other.

[0044] The pocket 633 protrudes from the end of the cylindrical portion 631 opposite to the planetary gear 4. The pocket 633 has an internal space that is recessed from the radially inner side to the radially outer side of the sun gear 2 (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.

[0045] That is, the pocket 633 has a bottom wall intersecting the radial direction of the sun gear 2, two side walls intersecting the circumferential direction of the sun gear 2, and a front wall intersecting the X-axis. The front wall covers a part of the planetary gear bearing 5 and a part of the cylindrical portion 631 in a direction parallel to the X-axis. Liquid can enter the internal space of the pocket 633 from the radial inside of the sun gear 2. The internal space of the pocket 633 is also connected to the hollow portion of the cylindrical portion 631.

[0046] The multiple bearing holders 63 are integrated with the housing 61 as part of the first part 61A. Furthermore, the cylindrical part 631 and the pocket 633 are integrated. The pocket 633 is formed simultaneously with the hole of the cylindrical part 631 when the first part 61A is processed. This makes it possible to form the pocket 633 relatively easily, which is difficult to form by casting due to its small thickness.

[0047] <First Sleeve> The first sleeve 64 shown in FIG. 1 is a cylindrical portion that is connected to the housing portion 61 and through which the first output shaft 8A is inserted.

[0048] The first sleeve 64 extends along the X-axis from the accommodating portion 61 toward the motor shaft 10. The first sleeve 64 communicates between the internal space of the accommodating portion 61 and the outside of the accommodating portion 61 (specifically, the internal space of the sun gear 2).

[0049] 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 rotational axis of the sun gear 2. The inner diameter of the first sleeve 64 is smaller than the maximum inner diameter of the accommodating portion 61.

[0050] <Oil drain groove> As shown in FIG. 4, the first oil drain groove 65A, the second oil drain groove 65B, the third oil drain groove 65C and the fourth oil drain groove 65D are provided on the inner surface of the first sleeve 64 and extend from the outer end portion 64A of the first sleeve 64 to the inside of the accommodating portion 61.

[0051] 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 apart from one another in the circumferential direction of the first sleeve 64. The shapes of the oil discharge grooves 65A-65D will be described in detail later.

[0052] <Second Sleeve> The second sleeve 66 shown in FIG. 1 is a cylindrical portion that is connected to the housing portion 61 and through which the second output shaft 8B is inserted.

[0053] The second sleeve 66 extends along the X-axis from the accommodating portion 61 toward the open end 9A of the gear case 9. The second sleeve 66 communicates between the internal space of the accommodating portion 61 and the outside of the accommodating portion 61 (specifically, the internal space of the gear case 9).

[0054] The second sleeve 66 is inserted into the differential case bearing 93. The central axis of the second sleeve 66 coincides with the rotational axis of the sun gear 2. The inner diameter of the second sleeve 66 is smaller than the maximum inner diameter of the accommodating portion 61.

[0055] 3, the second sleeve 66 has a first convex portion 661 and a second convex portion 662. The first convex portion 661 and the second convex portion 662 each protrude in the axial direction of the second side gear 75 (i.e., along the X-axis) at the outer end portion 66A of the second sleeve 66 further than other portions.

[0056] One end of the first convex portion 661 in the circumferential direction of the second sleeve 66 is located at a position continuous with the first oil introduction groove 67A, and the other end is located at a position continuous with the third oil introduction groove 67C.

[0057] That is, the first convex portion 661 is provided in a region between an end of the first oil introduction groove 67A and an 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 that guides oil to the first oil introduction groove 67A and the third oil introduction groove 67C.

[0058] The second protrusion 662 has a shape obtained by rotating the first protrusion 661 by 180 degrees around the rotation axis of the differential case 6. One end of the second protrusion 662 in the circumferential direction of the second sleeve 66 is provided at a position continuous with the second oil introduction groove 67B (see FIG. 5), and the other end is provided at a position continuous with the fourth oil introduction groove 67D (see FIG. 5).

[0059] That is, the second convex portion 662 is provided in a region between an end of the second oil introduction groove 67B and an 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 that guides oil to the second oil introduction groove 67B and the fourth oil introduction groove 67D.

[0060] <Oil inlet groove> As shown in Figure 5, the first oil inlet groove 67A, the second oil inlet groove 67B, the third oil inlet groove 67C and the fourth oil inlet groove 67D are provided on the inner surface of the second sleeve 66 and extend from the outer end portion 66A of the second sleeve 66 to the inside of the accommodating portion 61.

[0061] 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 apart from one another in the circumferential direction of the second sleeve 66. The shapes of the oil introduction grooves 67A-67D will be described in detail later.

[0062] <Differential mechanism> The differential mechanism 7 shown in FIG. 1 is a known mechanism that distributes and transmits the rotation of the differential case 6 to the first output shaft 8A and the second output shaft 8B while differentially rotating the first output shaft 8A and the second output shaft 8B.

[0063] The differential mechanism 7 has a first pinion gear 71, a second pinion gear 72 (see FIG. 5), a pinion shaft 73, a first side gear 74, and a second side gear 75. The differential mechanism 7 is disposed inside the differential case 6. Specifically, the first pinion gear 71, the second pinion gear 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.

[0064] <Pinion gear and pinion shaft> As shown in FIG. 5, first pinion gear 71 and second pinion gear 72 are each a bevel gear having a rotation axis perpendicular to the rotation axis of sun gear 2 (that is, the X-axis).

[0065] The rotation axis of first pinion gear 71 and the rotation axis of second pinion gear 72 coincide with each other. In addition, first pinion gear 71 and second pinion gear 72 are disposed to face each other. First pinion gear 71 and second pinion gear 72 have the same shape and are in a mirror image relationship with each other.

[0066] The pinion shaft 73 rotatably supports the first pinion gear 71 and the second pinion gear 72. The central axis (i.e., the longitudinal direction) of the pinion shaft 73 is perpendicular to the X-axis. The pinion shaft 73 is fixed to the housing portion 61 and does not rotate with respect to the differential case 6. In other words, the pinion shaft 73 rotates together with the housing portion 61 around the rotation axis of the sun gear 2.

[0067] <Side gear> As shown in FIG. 1, each of the first side gear 74 and the second side gear 75 is a bevel gear having a rotation axis that coincides with the rotation axis of the sun gear 2 (that is, the X-axis).

[0068] 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 to face each other.

[0069] The first side gear 74 is disposed along the X-axis 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 mirror images of each other.

[0070] The first side gear 74 and the second side gear 75 are each rotatably held by the housing 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.

[0071] The first side gear 74 and the second side gear 75 rotate together with the differential case 6 and at the same time rotate relatively to the differential case 6 due to the rotation transmitted from the first pinion gear 71 and the second pinion gear 72 .

[0072] <Output shaft> The first output shaft 8A and the second output shaft 8B are spline-fitted to a first side gear 74 and a second side gear 75, respectively.

[0073] 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 rotate differentially by the differential mechanism 7 connected thereto, and rotate in accordance with the rotation direction of the motor shaft 10 (i.e., the rotation direction of the differential case 6).

[0074] <Gear case> The gear case 9 accommodates the sun gear 2, the ring gear 3, and the plurality of planetary gears 4, and also supports the differential case 6 for rotation.

[0075] The gear case 9 has 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 define a planetary gear accommodating space that accommodates each gear and the differential case 6. A motor (not shown) serving as a drive source is disposed inside the second body 92.

[0076] The first body 91 has an open end 9A through which the second output shaft 8B is inserted. Lubricating oil for lubricating the gears and shafts is stored in the planetary gear accommodating space of the gear case 9. The planetary gear accommodating space is sealed by a seal member or the like.

[0077] The differential case bearing 93 rotatably supports the differential case 6. Specifically, the second sleeve 66 of the differential case 6 is inserted into the differential case bearing 93. The differential case bearing 93 is held by the first body 91. The differential case bearing 93 is a shielded bearing through which lubricating oil supplied from an oil guide 94 can pass.

[0078] 6 and 7 is a gutter-shaped flow passage arranged in the planetary gear housing space. An inlet 941 of the oil guide 94 is arranged above the rotation axis of the sun gear 2 and radially outside the orbits of the planetary gears 4. The inlet 941 is also arranged at a position overlapping with the first gear portions 41 of the planetary gears 4 in the radial direction of the sun gear 2.

[0079] 7, when the vehicle moves forward, the sun gear 2 and the differential case 6 rotate clockwise, and the planetary gears 4 each rotate counterclockwise while revolving clockwise. When the vehicle moves backward, the rotation direction of each member is opposite to these.

[0080] The lubricating oil stored below the planetary gear accommodating space is pumped up by the revolving planetary gear 4 and drips into the inlet 941. As a result, the lubricating oil is supplied into the oil guide 94.

[0081] The outlet 942 of the oil guide 94 is disposed below the inlet 941 and in the vicinity of the upper end of the outer end 66A of the second sleeve 66 of the differential case 6 (see FIG. 1). The lubricating oil supplied to the oil guide 94 from the inlet 941 slides down inside the oil guide 94 and is supplied to the vicinity of the second sleeve 66.

[0082] 2, the lubricating oil supplied near the second sleeve 66 passes through the second sleeve 66 and is supplied to the inside of the housing 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 into the inside of the sun gear 2 (i.e., the connecting member).

[0083] The lubricating oil discharged into the sun gear 2 is discharged from the communication hole 23 into the planetary gear accommodating space and is again stored in the lower part of the planetary gear accommodating space. The lubricating oil stored in the planetary gear accommodating space is supplied to the oil guide 94 by the planetary gear 4 as described above. The lubricating oil circulates within the gear case 9 in this manner.

[0084] In addition, some of the lubricating oil supplied near the second sleeve 66 passes through the shield of the differential case bearing 93 without being supplied to the storage section 61, slides downwardly of the second sleeve 66 and the storage section 61, and is stored in the lower part of the planetary gear storage space.

[0085] <Supply of lubricating oil to planetary gear bearings> 8, a portion of the lubricating oil flows along the inner circumferential surface of the first main body 91 of the gear case 9 and is supplied to the planetary gear bearing 5. The flow of this lubricating oil will be described in detail below.

[0086] The first main body 91 of the gear case 9 has a protrusion 911, an inclined surface 912, and a recess 913. The protrusion 911 overlaps with each of the pockets 633 of the multiple bearing holders 63 from the radial inner side of the sun gear 2, and protrudes toward the multiple planetary gear bearings 5 ​​in the axial direction of the sun gear 2.

[0087] That is, the protrusion 911 is a portion that protrudes from the inner surface of the first main body 91 so as to cover a part of the opening of the pocket 633. The protrusion 911 is located radially inward of the sun gear 2 with respect to the rotation axis L of the planetary gear 4 (i.e., the central axis of the planetary gear bearing 5).

[0088] In this embodiment, the protrusion 911 is formed in an annular shape when viewed from the axial direction of the sun gear 2. That is, the protrusion 911 is provided over the entire circumferential direction of the first main body 91. However, the protrusion 911 may be provided only on a lower part of the first main body 91 (for example, a part below the rotation axis of the sun gear 2).

[0089] The inclined surface 912 is inclined toward the protrusion 911 from a side farther from the planetary gear bearing 5 than the protrusion 911 in the axial direction of the sun gear 2 and from the inner side than the protrusion 911 in the radial direction of the sun gear 2.

[0090] That is, the inclined surface 912 is configured by a portion of the inner surface of the first main body 91 that extends from the protrusion 911 toward the opening end 9A. The inclined surface 912 may be configured by a flat surface, or may be curved or bent.

[0091] The recess 913 is disposed on the rear surface of the protrusion 911 on the radially outer side of the sun gear 2 (i.e., the surface opposite to the inclined surface 912), and is a portion recessed toward the radially inner side of the sun gear 2. The recess 913 is a groove extending along the circumferential direction of the sun gear 2. The recess 913 may be provided over the entire circumferential direction of the first main body 91, or may be provided only in a lower part of the first main body 91 (for example, a portion where the lubricating oil that enters the recess 913 falls).

[0092] The lubricating oil that passes through the oil guide 94, passes through the shield of the differential case bearing 93, and flows down below the second sleeve 66, or the lubricating oil that does not pass through the oil guide 94 but reaches the inclined surface 912 directly by being scattered inside the gear case 9, flows along the inclined surface 912 toward the protrusion 911, as shown by the arrow in Figure 8. The lubricating oil that reaches the protrusion 911 falls downward from the tip of the protrusion 911 and is collected inside the pocket 633.

[0093] Furthermore, the lubricating oil that has flowed around from the tip of the protrusion 911 to the rear surface of the protrusion 911 is removed from the rear surface of the protrusion 911 by the recess 913. Therefore, the lubricating oil is prevented from flowing downward in the pocket 633 along the inner surface of the first main body 91.

[0094] <Oil supply groove and oil discharge groove shapes> 5, the oil introduction grooves 67A-67D each reach the internal space of the accommodating portion 61 radially outward of the second side gear 75 when viewed in the axial direction of the second side gear 75 (i.e., in a direction parallel to the X-axis). The outlet ends of the oil introduction grooves 67A-67D each have a portion that does not overlap with the rotating second side gear 75.

[0095] Further, the oil introduction grooves 67A-67D are arranged so as not to overlap both the first pinion gear 71 and the second pinion gear 72 when viewed in the axial direction of the second side gear 75.

[0096] The first oil introduction groove 67A and the second oil introduction groove 67B are arranged side by side between the first pinion gear 71 and the second pinion gear 72 in the circumferential direction of the second side gear 75. The shape of the second oil introduction groove 67B is symmetrical to the first oil introduction groove 67A with respect to an imaginary plane perpendicular to the Y axis.

[0097] The third oil introduction groove 67C and the fourth oil introduction groove 67D have a symmetric shape to the first oil introduction groove 67A or the second oil introduction groove 67B with respect to an imaginary plane perpendicular to the Z axis. That is, the third oil introduction groove 67C and the fourth oil introduction groove 67D are disposed on the opposite side of the pinion shaft 73 to the first oil introduction groove 67A and the second oil introduction groove 67B, and are disposed side by side between the first pinion gear 71 and the second pinion gear 72 in the circumferential direction of the second side gear 75.

[0098] Each of the oil introduction grooves 67A-67D extends linearly. That is, for each of the oil introduction grooves 67A-67D, a line connecting the center points in the width direction of the groove is a straight line. Each of the oil introduction grooves 67A-67D also widens toward the accommodation portion 61. That is, the width of each of the oil introduction grooves 67A-67D is minimum at the outer end portion 66A of the second sleeve 66 and maximum inside the accommodation portion 61.

[0099] As shown in Figures 9A and 9B, the first convex portion 661 and the second convex portion 662 of the second sleeve 66 sandwich the first oil introduction groove 67A and the second oil introduction groove 67B in the circumferential direction of the second side gear 75 (i.e., the circumferential direction of the second sleeve 66), and also sandwich the third oil introduction groove 67C and the fourth oil introduction groove 67D in another area.

[0100] Specifically, each end of the first oil introduction groove 67A and the second oil introduction groove 67B is disposed in a region sandwiched between a first end 661A of the first convex portion 661 and a first end 662A of the second convex portion 662. Each end of the third oil introduction groove 67C and the fourth oil introduction groove 67D is disposed in a region sandwiched between a second end 661B of the first convex portion 661 and a second end 662B of the second convex portion 662.

[0101] 9A, when the differential case 6 rotates in the first direction R1 relative to the second output shaft 8B, the lubricating oil O in the planetary gear accommodating 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.

[0102] 9B, when the differential case 6 rotates in a second direction R2 opposite to the first direction R1 relative to the second output shaft 8B, the lubricating oil O in the planetary gear accommodating 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.

[0103] 10, the oil discharge grooves 65A-65D each reach the internal space of the accommodating section 61 radially outward of the first side gear 74 when viewed in the axial direction of the first side gear 74 (i.e., in a direction parallel to the X-axis). The outlet ends of the oil discharge grooves 65A-65D each have a portion that does not overlap with the rotating first side gear 74.

[0104] 10 is a view of the inside of the accommodating portion 61 as viewed from the second sleeve 66 side, and the first pinion gear 71, the second pinion gear 72, the pinion shaft 73, and the second side gear 75 are not shown.

[0105] The oil discharge grooves 65A-65D are each disposed at a position overlapping with the first pinion gear 71 or the second pinion gear 72, when viewed from the axial direction of the first side gear 74. Also, the oil discharge grooves 65A-65D are each disposed between any two of the oil introduction grooves 67A-67D in the circumferential direction of the first side gear 74, when viewed from the axial direction of the first side gear 74.

[0106] 4, the oil discharge grooves 65A-65D each extend linearly. Furthermore, the oil discharge grooves 65A-65D each increase in width toward the outer end 64A of the first sleeve 64. That is, the width of the oil introduction grooves 67A-67D is minimum in the housing portion 61 and maximum inside the outer end 64A of the first sleeve 64.

[0107] [1-2. Effects] According to the embodiment described above in detail, the following effects can be obtained.

[0108] (1a) The oil inlet grooves 67A-67D and the oil discharge grooves 65A-65D form an oil circulation path that lubricates the differential mechanism 7 within the housing portion 61. In addition, the oil inlet grooves 67A-67D are arranged so as not to overlap with the pinion gears 71, 72, thereby suppressing the interruption of the supply of oil to the housing portion 61 due to the rotation of the pinion gears 71, 72. As a result, the lubrication of the differential mechanism 7 can be improved without using a pump.

[0109] (1b) When the differential case 6 rotates in the first direction R1 relative to the second output shaft 8B (for example, when the rotation speed of the second output shaft 8B is higher than the rotation speed of the differential case 6), the oil is guided to the first oil introduction groove 67A by the first convex portion 661, and when the differential case 6 rotates in the second direction R2 relative to the second output shaft 8B (for example, when the rotation speed of the second output shaft 8B is lower than the rotation speed of the differential case 6), the oil is guided to the second oil introduction groove 67B by the second convex portion 662. Therefore, oil can be efficiently supplied to the differential mechanism 7 regardless of the rotation speed and direction of the second output shaft 8B.

[0110] (1c) Because the oil inlet grooves 67A-67D are linear, it is possible to suppress changes in oil supply efficiency depending on the direction of rotation of the differential case 6. In addition, because the oil inlet grooves 67A-67D are widened, oil can be efficiently supplied to the differential mechanism 7 by the centrifugal force that accompanies the rotation of the differential case 6.

[0111] 2. Other embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

[0112] (2a) In the transmission device of the above embodiment, the second sleeve does not necessarily have to have the first convex portion and the second convex portion.

[0113] (2b) In the transmission device of the above embodiment, the oil inlet groove does not necessarily have to be linear. For example, the oil inlet groove may be spiral. Furthermore, the oil inlet groove does not necessarily have to widen toward the housing portion. For example, the oil inlet groove may have a constant width along the longitudinal direction.

[0114] (2c) In the transmission device of the above embodiment, the number of oil inlet grooves and oil discharge grooves is not limited to 4. For example, the number of oil inlet grooves and oil discharge grooves may each be 3 or less (including 1).

[0115] (2d) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, a part of the configuration of the above embodiments may be omitted. In addition, at least a part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. Note that all aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure.

Claims

1. A sun gear and A ring gear arranged concentrically with the sun gear; a plurality of planetary gears meshing with the sun gear and the ring gear; a differential case that rotatably supports the plurality of planetary gears; A differential mechanism disposed inside the differential case; a first output shaft and a second output shaft connected to the differential mechanism; A gear case that rotatably supports the differential case; Equipped with The differential mechanism includes: a first pinion gear and a second pinion gear facing each other and having a rotation axis perpendicular to a rotation axis of the sun gear; a first side gear and a second side gear facing each other and having a rotation axis coinciding with a rotation axis of the sun gear; having the first side gear meshes with the first pinion gear and the second pinion gear and is connected to the first output shaft, the second side gear meshes with the first pinion gear and the second pinion gear and is connected to the second output shaft, The differential case is an accommodating portion that accommodates the first pinion gear, the second pinion gear, the first side gear, and the second side gear; a first sleeve connected to the housing portion and through which the first output shaft is inserted; a second sleeve connected to the housing portion and through which the second output shaft is inserted; At least one oil drain groove is provided on an inner circumferential surface of the first sleeve and extends from an outer end of the first sleeve to an inside of the accommodating portion; at least one oil introduction groove provided on an inner circumferential surface of the second sleeve and extending from an outer end of the second sleeve to an inside of the accommodating portion; having a transmission device in which, when viewed from the axial direction of the second side gear, the at least one oil introduction groove reaches the internal space of the accommodating portion radially outside the second side gear, and is arranged so as not to overlap with either the first pinion gear or the second pinion gear, extends in a straight line, and widens toward the accommodating portion.

2. 2. The transmission device according to claim 1, The differential case has, as the at least one oil inlet groove, a first oil inlet groove and a second oil inlet groove arranged side by side between the first pinion gear and the second pinion gear in a circumferential direction of the second side gear, the second sleeve has a first protruding portion and a second protruding portion protruding in an axial direction of the second side gear at the outer end portion, the first convex portion and the second convex portion are arranged to sandwich the first oil introduction groove and the second oil introduction groove in a circumferential direction of the second side gear.

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