Power transmission device

Abstract

To provide a power transmission device for allowing a fixing pin for fixing a differential pinion shaft to a differential case to be easily removed from the differential case.SOLUTION: A differential case 321 has a fixing pin insertion hole 321d which is integrally formed side by side with a planetary carrier 316 of a planetary gear mechanism 31 in the direction of the rotation axis and through which a fixing pin 400 is inserted to fix a differential pinion shaft 322 to the differential case 321. The fixing pin insertion hole 321d is provided parallel to the rotation axis of the differential case 321 and perpendicular to a differential pinion shaft insertion hole 321c through which the differential pinion shaft 322 is inserted. Besides, it is provided at a position of overlap with a pinion shaft insertion hole 316d of the planetary carrier 316 when viewing the differential case 321 from the direction of the rotation axis, so that one end is communicated with the pinion shaft insertion hole 316d and the other end is communicated with outside on the opposite side to the planetary carrier 316 of the differential case 321.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a power transmission device. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have been gaining momentum as a concrete measure against global climate change. For automobiles and other vehicles, there is a demand to reduce CO2 emissions and improve energy efficiency, and the use of electric drive sources is on the rise. In addition, from the perspective of environmental conservation, there has been an increasing demand in recent years for the reduction of discarded parts and the reuse of parts.

[0003] The following Patent Document 1 discloses a technology in which the pinion gear shaft of the rear differential is positioned on an axis that is within the storage space of the differential case and perpendicular to the rotation axis of the differential case, and rotation around and movement in the axial direction of the differential case are regulated by a pin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-007442 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above conventional technology has a problem in that it is difficult to remove the pin that restricts the rotation and movement of the pinion gear shaft from the differential case after the pin is attached to the differential case. Therefore, for example, when the pinion gear shaft needs to be removed from the differential case during assembly or inspection of the rear differential, the differential case must generally be destroyed to remove the pinion gear shaft, making it difficult to reuse the differential case, etc.

[0006] The present invention provides a power transmission device in which a fixing pin for fixing a differential pinion shaft to a differential case can be easily removed from the differential case even after the fixing pin is attached to the differential case. [Means for solving the problem]

[0007] The present invention relates to A power transmission device including a planetary gear mechanism and a differential gear mechanism, the planetary gear mechanism includes a planetary carrier having a pinion shaft insertion hole through which a planetary pinion shaft that axially supports a planetary gear is inserted, The differential gear mechanism has a differential case that supports a differential pinion shaft, The differential case is The differential case is formed integrally with the planetary carrier in a state aligned with the planetary carrier in the direction of the rotation axis of the differential case, a differential pinion shaft insertion hole provided perpendicular to a rotation axis of the differential case and through which the differential pinion shaft is inserted; a fixing pin insertion hole that is provided parallel to a rotation axis of the differential case and perpendicular to the differential pinion shaft insertion hole, and through which a fixing pin is inserted to fix the differential pinion shaft inserted into the differential pinion shaft insertion hole to the differential case; having The fixing pin insertion hole is located at a position overlapping with the pinion shaft insertion hole when the planetary carrier and the differential case are viewed from the rotation axis direction, one end is connected to the pinion shaft insertion hole and the other end is connected to the outside of the differential case on the opposite side from the planetary carrier. Effect of the Invention

[0008] According to the present invention, it is possible to provide a power transmission device in which the fixing pin for fixing the differential pinion shaft to the differential case can be easily removed from the differential case even after the fixing pin has been attached to the differential case. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a vehicle V equipped with a drive unit 10 that is an embodiment of a power transmission device of the present invention, as viewed from the left. [Diagram 2] FIG. 2 is a perspective view of a drive unit 10, with a part cut away. [Diagram 3] 2 is a partially cutaway perspective view for explaining a power transmission path in the drive unit 10. FIG. [Figure 4] 2 is a skeleton diagram of a reduction gear 30 in the drive unit 10. FIG. [Diagram 5] 2 is a rear perspective view of a planetary carrier 316 of a planetary gear mechanism 31 and a differential case 321 of a differential gear mechanism 32 included in the reduction gear 30. FIG. [Figure 6] 11 is a schematic diagram showing a first example of the positional relationship between a pinion shaft insertion hole 316d of a planetary carrier 316 and a fixing pin insertion hole 321d of a differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction. FIG. [Figure 7] 2 is a partial cross-sectional view of the drive unit 10 taken along a plane parallel to a differential pinion shaft 322 and a fixing pin 400 attached to a differential case 321. FIG. [Figure 8] 13 is a schematic diagram showing a second example of the positional relationship between a pinion shaft insertion hole 316d of the planetary carrier 316 and a fixing pin insertion hole 321d of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction. FIG. [Figure 9] 13 is a schematic diagram showing a third example of the positional relationship between a pinion shaft insertion hole 316d of the planetary carrier 316 and a fixing pin insertion hole 321d of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A vehicle equipped with a drive unit (drive unit 10 described below) that is one embodiment of the power transmission device of the present invention will be described below with reference to the accompanying drawings. In the following, identical or similar elements are given identical or similar reference symbols, and their description may be omitted or simplified as appropriate. The drawings are to be viewed according to the orientation of the reference symbols. In addition, in this specification and the like, for the sake of simplicity and clarity of explanation, the front / rear, left / right, and up / down directions are described according to the direction as seen by the driver of the vehicle, and in the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the top as U, and the bottom as D.

[0011] [Overall vehicle configuration] As shown in Fig. 1, a vehicle V of this embodiment has a pair of left and right front wheels FW, a pair of left and right rear wheels RW, and a floor panel FP that constitutes the floor of the vehicle V. The vehicle V is partitioned into a passenger compartment CB and a front room FRM in front of the passenger compartment CB by a dash panel DP that extends in the vertical direction above the floor panel FP. A front seat FS and a rear seat RS are provided in the passenger compartment CB.

[0012] The vehicle V includes a drive unit 10 serving as a drive source, and a battery pack IPU that stores electric power to be supplied to the drive unit 10.

[0013] The drive unit 10 is disposed behind the rear seat RS and below the floor panel FP. The battery pack IPU is disposed under the floor of the vehicle compartment CB below the floor panel FP. The battery pack IPU houses a plurality of battery modules, each of which has a plurality of stacked battery cells. Each battery cell is a rechargeable secondary battery, such as a lithium ion battery or a solid-state battery.

[0014] [Overall configuration of drive unit] As shown in Figures 2 and 3, the drive unit 10 includes a drive motor 20, a reduction gear 30 that reduces the power output from the drive motor 20 and outputs it to the outside, a chain transmission mechanism 4 that transmits the power output from the drive motor 20 to the reduction gear 30, a control device 50 that controls the drive motor 20, a parking mechanism 6, and a drive unit case 11 that houses these.

[0015] The drive unit case 11 has a main case 111 , a left side cover 112 that covers the left side surface of the main case 111 , and a right side cover 113 that covers the right side surface of the main case 111 .

[0016] The drive unit case 11 has a motor chamber 12 that houses the drive motor 20, a gear chamber 13 that houses the reduction gear 30, a chain chamber 14 that houses the chain transmission mechanism 4 and the parking mechanism 6, and a controller chamber 15 that houses the control device 50. The motor chamber 12 and the gear chamber 13 are formed side by side in the front-to-rear direction, with the motor chamber 12 at the front and the gear chamber 13 at the rear. The chain chamber 14 is formed on the left side of the motor chamber 12 and the gear chamber 13, and is formed by a main case 111 and a left side cover 112. The controller chamber 15 is formed on the right side of the motor chamber 12 and the gear chamber 13, and is formed by the main case 111 and a right side cover 113.

[0017] The drive motor 20 is a so-called inner rotor type motor that includes a drive shaft 21, a rotor 22 that is attached to the drive shaft 21 and rotates integrally with the drive shaft 21, and a stator 23 that is arranged radially opposite the rotor 22 with a small gap between them on the radial outside of the rotor 22.

[0018] In this embodiment, in the drive unit 10, the drive motor 20 is arranged so that the axial direction (i.e., the drive shaft 21) faces horizontally in the left-right direction. By arranging the drive shaft 21 so that it faces horizontally in this manner, the vertical dimension of the drive unit 10 can be made compact.

[0019] The stator 23 includes a stator core 231 and a coil 232 attached to the stator core 231 and configured with a plurality of windings of U-phase, V-phase, and W-phase.

[0020] A drive sprocket 21a around which the power transmission chain 40 of the chain transmission mechanism 4 is wound is attached to the left end of the drive shaft 21. The drive sprocket 21a rotates integrally with the drive shaft 21.

[0021] The chain transmission mechanism 4 includes a drive sprocket 21a attached to the drive shaft 21, a driven sprocket 311a attached to an input shaft 311 of a planetary gear mechanism 31 (described later) on the same plane as the drive sprocket 21a, and a power transmission chain 40 wound around the drive sprocket 21a and the driven sprocket 311a. The driven sprocket 311a has a larger diameter than the drive sprocket 21a, and the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a.

[0022] As shown in FIGS. 3 and 4, the reduction gear device 30 of the drive unit 10 includes a planetary gear mechanism 31 and a differential gear mechanism 32.

[0023] The planetary gear mechanism 31 has an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinions 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0024] In this embodiment, the planetary gear mechanism 31 is arranged side by side in the front-rear direction behind the drive motor 20. The planetary gear mechanism 31 is arranged so that its axial direction (i.e., the input shaft 311) faces in the left-right direction parallel to the axial direction of the drive motor 20. The input shaft 311 of the planetary gear mechanism 31 is also arranged at a position at approximately the same height in the up-down direction as the drive shaft 21 of the drive motor 20. Furthermore, the outer diameter dimension of the planetary gear mechanism 31 is approximately the same as the outer diameter dimension of the drive motor 20, and the height of the drive unit 10 in the up-down direction is reduced.

[0025] The input shaft 311 is a hollow shaft, and a left drive shaft 325L, which will be described later, is inserted inside. A driven sprocket 311a, around which the power transmission chain 40 of the chain transmission mechanism 4 is wound, is attached to the left end of the input shaft 311. The driven sprocket 311a rotates integrally with the input shaft 311.

[0026] The sun gear 312 is an external gear provided on the input shaft 311 and rotates integrally with the input shaft 311 on the same rotation axis.

[0027] The multiple planetary pinion shafts 313 are arranged radially outside the sun gear 312, facing in the left-right direction parallel to the input shaft 311, and at equal intervals in the circumferential direction along the outer circumferential surface of the sun gear 312. More specifically, in this embodiment, four planetary pinion shafts 313 are arranged at 90 degree intervals in the circumferential direction along the outer circumferential surface of the sun gear 312.

[0028] A stepped pinion 314 having a first planetary gear 314a and a second planetary gear 314b that rotate integrally with the planetary pinion shaft 313 is rotatably supported on each of the planetary pinion shafts 313.

[0029] First planetary gear 314 a is an external gear that is disposed on the outer circumferential surface of sun gear 312 and meshes with sun gear 312 .

[0030] The second planetary gear 314 b is an external gear that is disposed on the inner circumferential surface of the ring gear 317 and meshes with the ring gear 317 .

[0031] The planetary carrier 316 connects the planetary pinion shafts 313. The planetary carrier 316 is integral with the planetary pinion shafts 313 and is rotatable about a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0032] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b can rotate about the planetary pinion shaft 313 and can revolve together with the planetary pinion shaft 313 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312). The planetary carrier 316 rotates together with the orbital motion of the stepped pinion 314 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0033] The ring gear 317 is an annular internal gear whose inner circumferential surface meshes with each of the second planetary gears 314b. In this embodiment, the ring gear 317 is fixed to the drive unit case 11, and the ring gear 317 itself does not rotate.

[0034] The differential gear mechanism 32 includes a differential case 321, a differential pinion shaft 322 supported by the differential case 321, a first bevel gear 323a and a second bevel gear 323b rotatably supported on the differential pinion shaft 322, a left side gear 324L and a right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b, and a left drive shaft 325L and a right drive shaft 325R.

[0035] The differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31. Therefore, the differential case 321 rotates integrally with the planetary carrier 316 of the planetary gear mechanism 31 on a rotation axis coaxial with the input shaft 311.

[0036] Next, a power transmission path of the power output from the drive motor 20 will be described.

[0037] Power generated by the drive motor 20 is output from the drive shaft 21, and the drive sprocket 21a attached to the drive shaft 21 rotates integrally with the drive shaft 21. When the drive sprocket 21a rotates, the driven sprocket 311a rotates due to the power transmission chain 40 wound around the drive sprocket 21a and the driven sprocket 311a attached to the input shaft 311 of the planetary gear mechanism 31. The input shaft 311 of the planetary gear mechanism 31 rotates integrally with the driven sprocket 311a. At this time, since the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a, the rotation of the drive shaft 21 is decelerated via the drive sprocket 21a, the power transmission chain 40, and the driven sprocket 311a, and is input to the input shaft 311 of the planetary gear mechanism 31.

[0038] In the planetary gear mechanism 31, power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. The stepped pinion 314 rotates and revolves around its axis. The planetary carrier 316 rotates integrally with the revolution of the stepped pinion 314. In the planetary gear mechanism 31, since the ring gear 317 is fixed, the rotation of the input shaft 311 is reduced in speed at a predetermined reduction ratio and transmitted to the planetary carrier 316.

[0039] In the differential gear mechanism 32, the differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31, and therefore rotates integrally with the rotation of the planetary carrier 316. Therefore, the power input to the input shaft 311 of the planetary gear mechanism 31 is reduced at a predetermined reduction ratio and input to the differential case 321 via the planetary carrier 316.

[0040] Therefore, the power output from the drive shaft 21 is input to the differential case 321 of the differential gear mechanism 32 via the power transmission chain 40 and the planetary gear mechanism 31, and the differential pinion shaft 322 revolves together with the differential case 321 around the rotation axis of the differential case 321.

[0041] When the vehicle V is moving straight, there is no difference in rotation between the left and right rear wheels RW, so the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate in response to the rotation of the differential pinion shaft 322. The left drive shaft 325L rotates together with the rotation of the left side gear 324L, causing the left rear wheel RW to rotate, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R, causing the right rear wheel RW to rotate.

[0042] When the vehicle V is turning, the differential pinion shaft 322 revolves and the first bevel gear 323a and the second bevel gear 323b rotate so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases, while the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate at different rotation speeds so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases. Then, the left drive shaft 325L rotates together with the rotation of the left side gear 324L to rotate the left rear wheel RW, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R to rotate the right rear wheel RW. Therefore, when the vehicle V is turning, the left drive shaft 325L and the right drive shaft 325R rotate so that the rotational speed of the rear wheel RW on the inside of the turn slows down and the rotational speed of the rear wheel RW on the outside of the turn increases.

[0043] In this manner, as shown by the arrows in FIG. 3, the power output from the drive motor 20 is decelerated via the drive sprocket 21a, the driven sprocket 311a, and the power transmission chain 40, and input to the reduction gear 30, where it is further decelerated by the planetary gear mechanism 31, and the power is appropriately distributed and transmitted to the left and right rear wheels RW by the differential gear mechanism 32.

[0044] [Planetary carrier and differential case] Next, the planetary carrier 316 and the differential case 321 will be described in more detail.

[0045] 5, the planetary carrier 316 is provided on the left side of the differential case 321 while being aligned in the left-right direction, which is the direction of the rotation axis of the differential case 321. The planetary carrier 316 has annular left wall portion 316a and right wall portion 316b facing each other in the left-right direction, and a cylindrical outer circumferential wall 316c connecting the annular left wall portion 316a and right wall portion 316b.

[0046] The left wall portion 316a and the right wall portion 316b are each provided with a pinion shaft insertion hole 316d through which each of the above-mentioned multiple planetary pinion shafts 313 is inserted. More specifically, in this embodiment, since the four planetary pinion shafts 313 are arranged at 90 degree intervals in the circumferential direction, the left wall portion 316a and the right wall portion 316b are each provided with four pinion shaft insertion holes 316d at 90 degree intervals so as to correspond to each of the four planetary pinion shafts 313. Hereinafter, the pinion shaft insertion hole 316d provided in the left wall portion 316a is also referred to as the "pinion shaft insertion hole 316dL," and the pinion shaft insertion hole 316d provided in the right wall portion 316b is also referred to as the "pinion shaft insertion hole 316dR."

[0047] 6 shows a first example of the positional relationship between a pinion shaft insertion hole 316d of the planetary carrier 316 and a fixing pin insertion hole 321d (described later) of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction. In FIG. 6, the dashed line labeled with reference numeral 322 represents the differential pinion shaft 322 attached to the differential case 321.

[0048] 6, the pinion shaft insertion holes 316dL of the left wall portion 316a and the pinion shaft insertion holes 316dR of the right wall portion 316b are provided to face each other in the left-right direction. The four planetary pinion shafts 313 described above are attached to the planetary carrier 316 by being inserted into the corresponding pairs of left and right pinion shaft insertion holes 316d (the pinion shaft insertion holes 316dL and the pinion shaft insertion holes 316dR).

[0049] 5, the outer peripheral wall 316c is provided with an opening 316e for exposing a part of the outer peripheral surface of the stepped pinion 314 (first planetary gear 314a and second planetary gear 314b) journaled on each planetary pinion shaft 313 attached to the planetary carrier 316 to the outside of the planetary carrier 316. The opening 316e is provided at a position corresponding to the stepped pinion 314 journaled on each planetary pinion shaft 313 in the radial direction centered on the rotation axis of the differential case 321.

[0050] 5, the differential case 321 has a housing portion 321a. The housing portion 321a houses the differential pinion shaft 322, the first bevel gear 323a, the second bevel gear 323b, the left side gear 324L, and the right side gear 324R.

[0051] The differential case 321 also has a pair of left and right drive shaft insertion holes 321b through which the left drive shaft 325L and the right drive shaft 325R are inserted and communicate with the accommodation portion 321a from the left-right direction, which is the rotation axis direction of the differential case 321, and a pair of differential pinion shaft insertion holes 321c through which the differential pinion shaft 322 is inserted and communicates with the accommodation portion 321a. The pair of differential pinion shaft insertion holes 321c are provided so as to communicate with approximately the center of the accommodation portion 321a in the left-right direction, which is the rotation axis direction of the differential case 321, and to be perpendicular to the rotation axis of the differential case 321.

[0052] Furthermore, the differential case 321 is provided with fixing pin insertion holes 321d through which fixing pins 400 (see FIG. 7) for fixing the differential pinion shafts 322 to the differential case 321 are inserted. The fixing pin insertion holes 321d are provided parallel to the rotation axis of the differential case 321 and perpendicular to each of the pair of differential pinion shaft insertion holes 321c.

[0053] As shown in FIG. 7, the fixing pin 400 is inserted into the fixing pin insertion hole 321d of the differential case 321 and the fixing pin insertion hole 322a provided near the end of the differential pinion shaft 322, thereby restricting the rotation of the differential pinion shaft 322 around an axis perpendicular to the rotation axis of the differential case 321 or movement in the axial direction.

[0054] In this embodiment, as shown in Fig. 6, the fixing pin insertion hole 321d of the differential case 321 is provided at a position overlapping with one of the pinion shaft insertion holes 316d provided in the planetary carrier 316 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction. Then, as shown in Fig. 7, a left end 321dL of the fixing pin insertion hole 321d communicates with one of the pinion shaft insertion holes 316dR provided in the right wall portion 316b of the planetary carrier 316, and a right end 321dR of the fixing pin insertion hole 321d communicates with the outside of the differential case 321 on the opposite side to the planetary carrier 316.

[0055] According to the configuration of this embodiment, when the fixing pin 400 for fixing the differential pinion shaft 322 to the differential case 321 is attached to the differential case 321, the fixing pin 400 can be attached to the differential case 321 by inserting the fixing pin 400 into the fixing pin insertion hole 321d from the right side of the differential case 321 as shown by the arrow with the symbol α in FIG. 7. In addition, when removing the fixing pin 400 attached to the differential case 321, as shown by the arrow with the symbol β in FIG. 7, the planetary pinion shaft 313 inserted into the pinion shaft insertion hole 316dR communicating with the fixing pin insertion hole 321d is appropriately removed, and the fixing pin 400 in the fixing pin insertion hole 321d is pushed out to the right of the differential case 321 through the pinion shaft insertion hole 316dR, so that the fixing pin 400 can be easily removed from the differential case 321.

[0056] Therefore, according to the configuration of this embodiment, even if it becomes necessary to remove the differential pinion shaft 322 from the differential case 321 during assembly or inspection of the differential gear mechanism 32, etc., the differential pinion shaft 322 can be removed from the differential case 321 without destroying the differential case 321, the fixing pin 400, the differential pinion shaft 322, etc., and these can be reused.

[0057] Furthermore, since the pinion shaft insertion hole 316dR (i.e., the pinion shaft insertion hole 316d) communicating with the fixed pin insertion hole 321d can be utilized as a hole used when pushing the fixed pin 400 out of the differential case 321, there is no need to provide an extra hole (a hole used only when pushing the fixed pin 400 out of the differential case 321) in the differential case 321. By providing such a hole, it is possible to avoid a decrease in the strength of the differential case 321 and the planetary carrier 316.

[0058] In addition, according to the configuration of this embodiment, the fixed pin insertion hole 321d of the differential case 321 and the pinion shaft insertion hole 316d of the planetary carrier 316 are in communication with each other. For example, when the planetary pinion shaft 313 is attached to or detached from the planetary carrier 316, the fixed pin insertion hole 321d communicating with the pinion shaft insertion hole 316d through which the planetary pinion shaft 313 is inserted functions as a so-called "air vent hole", making it possible to easily attach and detach the planetary pinion shaft 313. Similarly, when the fixed pin 400 is attached to or detached from the differential case 321, the pinion shaft insertion hole 316d communicating with the fixed pin insertion hole 321d through which the fixed pin 400 is inserted functions as an air vent hole, making it possible to easily attach and detach the fixed pin 400.

[0059] As described above, according to this embodiment, even after the fixing pin 400 for fixing the differential pinion shaft 322 to the differential case 321 is attached to the differential case 321, the fixing pin 400 can be easily removed from the differential case 321.

[0060] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this embodiment. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. In addition, the components in the above-mentioned embodiment may be arbitrarily combined within the scope of the invention.

[0061] For example, when the differential pinion shaft 322 is fixed to the differential case 321 by one fixing pin 400, the number of fixing pin insertion holes 321d may be one. Even when the differential pinion shaft 322 is fixed to the differential case 321 by one fixing pin 400, multiple fixing pin insertion holes 321d may be provided as shown in Fig. 6 and the like, and there may be fixing pin insertion holes 321d into which the fixing pin 400 is not actually inserted.

[0062] In the above-described example, the left wall portion 316a and the right wall portion 316b are each provided with four pinion shaft insertion holes 316d at 90 degree intervals along the circumferential direction, but the number of pinion shaft insertion holes 316d is not limited to four. In other words, as long as the fixing pin insertion hole 321d of the differential case 321 is provided at a position overlapping with any of the pinion shaft insertion holes 316d provided in the planetary carrier 316 when the planetary carrier 316 and the differential case 321 are viewed from the left and right, and is in communication with the pinion shaft insertion hole 316d, the number of the pinion shaft insertion holes 316d is not limited to four.

[0063] As one example, three pinion shaft insertion holes 316d may be provided at 120 degree intervals in the circumferential direction in each of the left wall portion 316a and the right wall portion 316b as shown in Fig. 8. As another example, five pinion shaft insertion holes 316d may be provided at 72 degree intervals in the circumferential direction in each of the left wall portion 316a and the right wall portion 316b as shown in Fig. 9.

[0064] The number of differential pinion shafts 322 attached to the differential case 321 is not limited to one, and may be, for example, two. In this case, fixing pin insertion holes 321d through which fixing pins 400 for fixing each differential pinion shaft 322 to the differential case 321 are inserted communicate with any one of the pinion shaft insertion holes 316d.

[0065] 8 and 9, dummy holes 316f may be provided at positions overlapping with the pinion shaft insertion holes 316d other than the pinion shaft insertion holes 316d communicating with the fixing pin insertion holes 321d when the differential case 321 is viewed from the left-right direction. In this case, like the fixing pin insertion holes 321d, one end of the dummy hole 316f communicates with the corresponding pinion shaft insertion hole 316d (pinion shaft insertion hole 316dR), and the other end communicates with the outside of the differential case 321 on the opposite side to the planetary carrier 316. By providing such dummy holes 316f, the dummy holes 316f communicating with each pinion shaft insertion hole 316d function as air bleed holes, making it possible to easily attach and detach the planetary pinion shafts 313.

[0066] This specification describes at least the following items. Note that, in parentheses, components corresponding to those in the above-mentioned embodiment are shown, but the present invention is not limited to these.

[0067] (1) A power transmission device (drive unit 10) including a planetary gear mechanism (planetary gear mechanism 31) and a differential gear mechanism (differential gear mechanism 32), The planetary gear mechanism includes a planetary carrier (planetary carrier 316) having a pinion shaft insertion hole (pinion shaft insertion hole 316d) through which a planetary pinion shaft (planetary pinion shaft 313) that supports a planetary gear (stepped pinion 314, first planetary gear 314a, second planetary gear 314b) is inserted, The differential gear mechanism has a differential case (differential case 321) that supports a differential pinion shaft (differential pinion shaft 322), The differential case is The differential case is formed integrally with the planetary carrier in a state aligned with the planetary carrier in the direction of the rotation axis of the differential case, A differential pinion shaft insertion hole (differential pinion shaft insertion hole 321c) through which the differential pinion shaft is inserted, the differential pinion shaft being provided perpendicular to the rotation axis of the differential case; A fixing pin insertion hole (fixing pin insertion hole 321d) is provided parallel to the rotation axis of the differential case and perpendicular to the differential pinion shaft insertion hole, and a fixing pin is inserted through the fixing pin that fixes the differential pinion shaft inserted into the differential pinion shaft insertion hole to the differential case. having The fixing pin insertion hole is provided at a position overlapping with the pinion shaft insertion hole when the planetary carrier and the differential case are viewed from the rotation axis direction, and one end (left end 321dL) communicates with the pinion shaft insertion hole, and the other end (right end 321dR) communicates with the outside of the differential case on the opposite side to the planetary carrier. Power transmission device.

[0068] According to (1), one end of the fixing pin insertion hole, through which the fixing pin that fixes the differential pinion shaft to the differential case is inserted, is connected to the pinion shaft insertion hole of the planetary carrier, and the other end is connected to the outside of the differential case on the opposite side from the planetary carrier. Therefore, the fixing pin in the fixing pin insertion hole can be easily removed from the differential case by pushing it out of the differential case through the pinion shaft insertion hole of the planetary carrier. [Explanation of symbols]

[0069] 10 Drive unit (power transmission device) 31 Planetary gear mechanism 313 Planetary pinion shaft 314 Step pinion (planetary gear) 314a 1st planetary gear (planetary gear) 314b 2nd planetary gear (planetary gear) 316 Planetary Carrier 32 Differential gear mechanism 321 Differential Case 321c Differential pinion shaft insertion hole 321d Fixing pin insertion hole 322 Differential pinion shaft

Claims

[Claim 1] A power transmission device including a planetary gear mechanism and a differential gear mechanism, the planetary gear mechanism includes a planetary carrier having a pinion shaft insertion hole through which a planetary pinion shaft that axially supports a planetary gear is inserted, The differential gear mechanism has a differential case that supports a differential pinion shaft, The differential case is The differential case is formed integrally with the planetary carrier in a state aligned with the planetary carrier in the direction of the rotation axis of the differential case, a differential pinion shaft insertion hole provided perpendicular to a rotation axis of the differential case and through which the differential pinion shaft is inserted; a fixing pin insertion hole that is provided parallel to a rotation axis of the differential case and perpendicular to the differential pinion shaft insertion hole, and through which a fixing pin is inserted to fix the differential pinion shaft inserted into the differential pinion shaft insertion hole to the differential case; having The fixing pin insertion hole is provided at a position overlapping with the pinion shaft insertion hole when the planetary carrier and the differential case are viewed from the rotation axis direction, and one end communicates with the pinion shaft insertion hole and the other end communicates with the outside of the differential case on the opposite side to the planetary carrier. Power transmission device.

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