Power transmission device

Abstract

Provided is 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. The differential case is formed integrally with a carrier of the planetary gear mechanism in a state of being aligned with the carrier in the rotational axis direction of the differential case. The differential case has a fixing pin through hole (321d) through which a fixing pin for fixing the differential pinion shaft to the differential case passes. The fixing pin through hole is arranged in parallel with a rotating shaft of the differential case and orthogonal to a differential pinion shaft through hole (321c) through which the differential pinion shaft passes, and the fixing pin through hole is further arranged at a position overlapped with the pinion shaft through hole of the planet carrier when the differential case is observed from the direction of the rotating shaft. One end of the fixing pin through hole is communicated with the small gear shaft through hole, and the other end of the fixing pin through hole is communicated with the outer portion of the side, opposite to the planet carrier, of the differential mechanism shell.

Description

Technical Field

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

[0002] In recent years, as a concrete countermeasure to global climate change, initiatives to achieve a low-carbon society or a decarbonized society have been very active. In vehicles such as automobiles, there are also demands to reduce CO2 emissions and improve energy efficiency, and the electrification of drive sources is also developing. In addition, from the perspective of environmental protection, there has been an increasing demand in recent years to reduce waste parts and reuse parts.

[0003] Patent Document 1 below discloses a technique in which a pinion shaft of a rear differential is arranged in a storage space of a differential case on an axis perpendicular to the rotation axis of the differential case, and rotation about the axis and movement along the axis are restricted by a pin.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-007442 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the above-mentioned prior art, there is a problem that after the pin for restricting the rotation and movement of the pinion shaft is mounted on the differential case, it is difficult to remove the pinion shaft from the differential case. Therefore, for example, when the pinion shaft is removed from the differential case during assembly or inspection of the rear differential, the method of removing the pinion shaft by destroying the differential case is generally adopted, and thus it is difficult to reuse the differential case and the like.

[0009] The present invention provides a power transmission device which can easily remove a fixing pin for fixing a differential pinion shaft to a differential case from the differential case even after the fixing pin has been installed to the differential case.

[0010] Solutions to Solve Problems

[0011] The present invention provides a power transmission device, which includes a planetary gear mechanism and a differential gear mechanism, wherein:

[0012] The planetary gear mechanism includes a planet carrier, the planet carrier includes a pinion shaft through hole, and the pinion shaft through hole is passed through by a planet pinion shaft for supporting the planetary gear.

[0013] The differential gear mechanism includes a differential case supporting a differential pinion shaft.

[0014] The differential case is formed integrally with the planetary carrier in a state where the differential case is aligned with the planetary carrier in the direction of the rotation axis of the differential case.

[0015] The differential housing has:

[0016] a differential pinion shaft through hole, which is provided in a manner perpendicular to the rotation axis of the differential case and through which the differential pinion shaft passes; and

[0017] a fixing pin through hole, which is arranged in parallel with the rotation axis of the differential case and orthogonal to the differential pinion shaft through hole and through which a fixing pin passes, and the fixing pin fixes the differential pinion shaft passing through the differential pinion shaft through hole to the differential case,

[0018] The fixing pin through hole is arranged at a position overlapping with the pinion shaft through hole when the planetary carrier and the differential case are viewed from the direction of the rotating axis, one end of the fixing pin through hole is connected to the pinion shaft through hole, and the other end of the fixing pin through hole is connected to the outside of the differential case on the opposite side of the planetary carrier.

[0019] Effects of the Invention

[0020] According to the present invention, it is possible to provide a power transmission device in which, even after the fixing pin for fixing the differential pinion shaft to the differential case has been attached to the differential case, the fixing pin can be easily removed from the differential case. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of a vehicle V mounted with a drive unit 10 as one embodiment of a power transmission device according to the present invention, as viewed from the left.

[0022] Figure 2 This is a perspective view showing a portion of the drive unit 10 cut away and observed.

[0023] Figure 3 It is a partially cutaway perspective view for explaining a power transmission path of the drive unit 10 .

[0024] Figure 4 1 is a skeleton diagram of the reduction gear device 30 in the drive unit 10 .

[0025] Figure 5 It is a perspective view of the planetary carrier 316 of the planetary gear mechanism 31 and the differential case 321 of the differential gear mechanism 32 included in the reduction gear device 30 as viewed from the rear.

[0026] Figure 61 is a schematic diagram showing a first example of the positional relationship between the pinion shaft through hole 316 d of the planetary carrier 316 and the fixing pin through hole 321 d of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction.

[0027] Figure 7 This is a partial cross-sectional view of the drive unit 10 cut along a plane parallel to the differential pinion shaft 322 attached to the differential case 321 and the fixing pin 400 .

[0028] Figure 8 1 is a schematic diagram showing a second example of the positional relationship between the pinion shaft through hole 316 d of the planetary carrier 316 and the fixing pin through hole 321 d of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction.

[0029] Fig. 9 1 is a schematic diagram showing a third example of the positional relationship between the pinion shaft through hole 316 d of the planetary carrier 316 and the fixing pin through hole 321 d of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left-right direction.

[0030] Description of reference numerals:

[0031] 10 Drive unit (power transmission device)

[0032] 31 Planetary gear mechanism

[0033] 313 planetary pinion shaft

[0034] 314 stepped pinion (planetary gear)

[0035] 314a First planetary gear (planetary gear)

[0036] 314b Second planetary gear (planetary gear)

[0037] 316 planet carrier

[0038] 32 Differential gear mechanism

[0039] 321 differential housing

[0040] 321c differential pinion shaft through hole

[0041] 321d fixing pin through hole

[0042] 322 Differential pinion shaft. DETAILED DESCRIPTION

[0043] Hereinafter, a vehicle equipped with a drive unit (drive unit 10 described later) as an embodiment of the power transmission device of the present invention is described based on the accompanying drawings. Hereinafter, the same or similar elements are marked with the same or similar figure marks, and their descriptions are sometimes appropriately omitted or simplified. In addition, the drawings are observed along the direction of the figure marks. In addition, in this specification, etc., in order to make the description simple and clear, the front and rear, left and right, and up and down directions are recorded according to the direction observed from the driver of the vehicle. In the accompanying drawings, the front of the vehicle is represented as Fr, the rear is represented as Rr, the left is represented as L, the right is represented as R, the top is represented as U, and the bottom is represented as D.

[0044]

Overall structure of the vehicle

[0045] like Figure 1 As shown, the vehicle V of this embodiment has a pair of left and right front wheels FW and a pair of left and right rear wheels RW, and a bottom panel FP constituting the bottom surface of the vehicle V. The vehicle V is divided into a vehicle compartment CB and a front cabin FRM in front thereof by a front control panel DP extending in the up-down direction above the bottom panel FP. Front seats FS and rear seats RS are provided in the vehicle compartment CB.

[0046] The vehicle V includes a drive unit 10 as a drive source and a battery unit IPU that stores electric power to be supplied to the drive unit 10 .

[0047] The drive unit 10 is arranged below the floor panel FP behind the rear seat RS. The battery pack IPU is arranged below the bottom surface of the vehicle compartment CB below the floor panel FP. The battery pack IPU accommodates a plurality of battery modules in which a plurality of cells are stacked. Each cell is a secondary battery that can be charged and discharged, such as a lithium-ion battery or an all-solid-state battery.

[0048] [Overall structure of the drive unit]

[0049] like Figure 2 and Figure 3 As shown, the drive unit 10 includes a drive motor 20, a reduction device 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 device 30, a control device 50 that controls the drive motor 20, a parking mechanism 6, and a drive unit housing 11 that accommodates them.

[0050] The drive unit case 11 has a main case 111 , a left side cover 112 covering the left side surface of the main case 111 , and a right side cover 113 covering the right side surface of the main case 111 .

[0051] The drive unit housing 11 has a motor chamber 12 that accommodates a drive motor 20, a gear chamber 13 that accommodates a reduction gear 30, a chain chamber 14 that accommodates a chain transmission mechanism 4 and a parking mechanism 6, and a controller chamber 15 that accommodates a control device 50. The motor chamber 12 and the gear chamber 13 are arranged in the front-to-back direction in such a manner that the motor chamber 12 is in the front and the gear chamber 13 is in 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 housing 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 a main housing 111 and a right side cover 113.

[0052] The driving motor 20 is a so-called inner rotor type motor, which includes a driving shaft 21, a rotor 22 mounted on the driving shaft 21 and rotating integrally with the driving shaft 21, and a stator 23 arranged to be radially opposed to the rotor 22 with a small gap radially outside the rotor 22.

[0053] In this embodiment, the drive motor 20 is arranged in the drive unit 10 with its axial direction (ie, the drive shaft 21) oriented horizontally in the left-right direction. Thus, by arranging the drive shaft 21 oriented horizontally, the vertical dimension of the drive unit 10 can be made compact.

[0054] The stator 23 includes a stator core 231 and a coil 232 mounted on the stator core 231 and composed of a plurality of windings such as a U-phase, a V-phase, and a W-phase.

[0055] 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 portion of the drive shaft 21. The drive sprocket 21a rotates integrally with the drive shaft 21.

[0056] The chain transmission mechanism 4 includes a driving sprocket 21a mounted on the driving shaft 21, a driven sprocket 311a mounted on the input shaft 311 of the planetary gear mechanism 31 described later on the same plane as the driving sprocket 21a, and a power transmission chain 40 wound around the driving sprocket 21a and the driven sprocket 311a. The diameter of the driven sprocket 311a is larger than that of the driving sprocket 21a, and the number of teeth of the driven sprocket 311a is greater than that of the driving sprocket 21a.

[0057] like Figure 3 and Figure 4 As shown, the reduction gear device 30 of the drive unit 10 includes a planetary gear mechanism 31 and a differential gear mechanism 32 .

[0058] The planetary gear mechanism 31 includes an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinion gears 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0059] In the present embodiment, the planetary gear mechanism 31 is arranged in the front-to-back direction behind the driving motor 20. The planetary gear mechanism 31 is arranged so that the axial direction (i.e., the input shaft 311) is parallel to the axial direction of the driving motor 20 and faces the left-right direction. In addition, the input shaft 311 of the planetary gear mechanism 31 is arranged at a position at substantially the same height as the driving shaft 21 of the driving motor 20 in the up-down direction. Furthermore, the outer diameter of the planetary gear mechanism 31 is substantially the same as the outer diameter of the driving motor 20, and the height of the driving unit 10 in the up-down direction is low.

[0060] The input shaft 311 is a hollow shaft, and a left drive shaft 325L described later passes through the inside of the input shaft 311. A driven sprocket 311a around which a power transmission chain 40 of the chain transmission mechanism 4 is wound is mounted at the left end of the input shaft 311. The driven sprocket 311a rotates integrally with the input shaft 311.

[0061] 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.

[0062] The plurality of pinion shafts 313 are arranged at equal intervals in the circumferential direction on the radially outer side of the sun gear 312 in a manner that they face the left-right direction in parallel with the input shaft 311. More specifically, in the present embodiment, the four pinion shafts 313 are arranged at 90-degree intervals in the circumferential direction along the outer circumferential surface of the sun gear 312.

[0063] The stepped pinion gear 314 including the first planetary gear 314 a and the second planetary gear 314 b that rotate integrally is supported on each of the planetary pinion shafts 313 so as to be freely rotatable.

[0064] The first planetary gear 314 a is an external gear that is disposed on the outer peripheral surface of the sun gear 312 and meshes with the sun gear 312 .

[0065] The second planetary gear 314 b is an external gear that is disposed on the inner peripheral surface of the ring gear 317 and meshes with the ring gear 317 .

[0066] The planetary carrier 316 connects the respective pinion shafts 313. The planetary carrier 316 and the pinion shafts 313 are rotatable integrally with each other on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0067] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b freely rotates about the planetary pinion shaft 313, and freely revolves on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the planetary pinion shaft 313. Furthermore, the planet carrier 316 rotates on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the revolving motion of the stepped pinion 314.

[0068] The ring gear 317 is an annular internal gear whose inner peripheral surface meshes with each of the second planetary gears 314b. In the present embodiment, the ring gear 317 is fixed to the drive unit case 11, and the ring gear 317 itself does not rotate.

[0069] 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 by 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.

[0070] The differential case 321 is formed integrally with the carrier 316 of the planetary gear mechanism 31. Therefore, the differential case 321 rotates integrally with the carrier 316 of the planetary gear mechanism 31 on a rotation axis coaxial with the input shaft 311.

[0071] Next, a power transmission path of the power output from the driving motor 20 will be described.

[0072] The power generated by the driving motor 20 is output from the driving shaft 21, and the driving sprocket 21a installed on the driving shaft 21 rotates integrally with the driving shaft 21. Moreover, when the driving sprocket 21a rotates, the driven sprocket 311a rotates due to the power transmission chain 40 wound on the driving sprocket 21a and the driven sprocket 311a installed on the input shaft 311 of the planetary gear mechanism 31. Moreover, the input shaft 311 of the planetary gear mechanism 31 rotates integrally with the driven sprocket 311a. At this time, the number of teeth of the driven sprocket 311a is greater than the number of teeth of the driving sprocket 21a, so the rotation of the driving shaft 21 is decelerated via the driving 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.

[0073] In the planetary gear mechanism 31, the power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. And, the stepped pinion 314 rotates while revolving. And, the planet carrier 316 rotates integrally with the revolving 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 decelerated at a predetermined reduction ratio and transmitted to the planet carrier 316.

[0074] 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 thus 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 in speed at a predetermined reduction ratio and input to the differential case 321 via the planetary carrier 316.

[0075] 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 about the rotation axis of the differential case 321 .

[0076] When the vehicle V is traveling straight, there is no rotation difference 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 accordance with the rotation of the differential pinion shaft 322. In addition, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the left rear wheel RW, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the right rear wheel RW.

[0077] When the vehicle V turns, the differential pinion shaft 322 revolves, and the first bevel gear 323a and the second bevel gear 323b rotate to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn, and 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 to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn. Moreover, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the rear wheel RW on the left side, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the rear wheel RW on the right side. Therefore, when the vehicle V turns, the left drive shaft 325L and the right drive shaft 325R rotate in a manner that slows down the rotation speed of the rear wheel RW on the inner side of the turn and speeds up the rotation speed of the rear wheel RW on the outer side of the turn.

[0078] In this way, Figure 3As shown by the arrow, the power output from the driving motor 20 is decelerated and input into the reduction device 30 via the driving sprocket 21a, the driven sprocket 311a and the power transmission chain 40, 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.

[0079]

Planet carrier and differential housing

[0080] Next, the planetary carrier 316 and the differential case 321 will be described in more detail.

[0081] like Figure 5 As shown, the planetary carrier 316 is provided on the left side of the differential case 321 in a state aligned with the differential case 321 in the rotation axis direction, i.e., the left-right direction. The planetary carrier 316 has an annular left wall portion 316a and a right wall portion 316b which are opposed to each other in the left-right direction, and a cylindrical outer peripheral wall 316c which connects the annular left wall portion 316a and the right wall portion 316b.

[0082] The left wall portion 316a and the right wall portion 316b are provided with pinion shaft through holes 316d through which the aforementioned plurality of pinion shafts 313 are respectively passed. More specifically, in the present embodiment, in order to arrange four pinion shafts 313 at intervals of 90 degrees in the circumferential direction, four pinion shaft through holes 316d are respectively provided at intervals of 90 degrees in the left wall portion 316a and the right wall portion 316b in a manner corresponding to the four pinion shafts 313. Hereinafter, the pinion shaft through hole 316d provided in the left wall portion 316a is also referred to as a "pinion shaft through hole 316dL", and the pinion shaft through hole 316d provided in the right wall portion 316b is also referred to as a "pinion shaft through hole 316dR".

[0083] Figure 6 The first example of the positional relationship between the pinion shaft through hole 316d of the planetary carrier 316 and the fixing pin through hole 321d (described later) of the differential case 321 when the planetary carrier 316 and the differential case 321 are viewed from the left and right directions is shown. Figure 6 In FIG. 1 , a dotted line with reference numeral 322 indicates a differential pinion shaft 322 mounted on a differential case 321 .

[0084] like Figure 6 As shown in FIG. 1 , the pinion shaft through holes 316dL of the left wall portion 316a and the pinion shaft through holes 316dR of the right wall portion 316b are arranged in a manner opposite to each other in the left-right direction. The aforementioned four planetary pinion shafts 313 are respectively passed through the corresponding left and right pairs of pinion shaft through holes 316d (pinion shaft through holes 316dL and pinion shaft through holes 316dR), and are thus mounted on the planetary carrier 316.

[0085] like Figure 5 As shown in the figure, an opening 316e is provided on the outer peripheral wall 316c, and the opening 316e is used to expose a part of the outer peripheral surface of the stepped pinion 314 (the first planetary gear 314a and the second planetary gear 314b) to the outside of the planetary carrier 316. The stepped pinion 314 is supported on each planetary pinion shaft 313 of the planetary carrier 316. The opening 316e is provided at a position corresponding to the stepped pinion 314 supported on each planetary pinion shaft 313 in the radial direction centered on the rotation axis of the differential case 321.

[0086] like Figure 5 As shown, the differential case 321 has a housing portion 321 a that houses the aforementioned differential pinion shaft 322 , the first bevel gear 323 a , the second bevel gear 323 b , the left side gear 324L, and the right side gear 324R.

[0087] Furthermore, the differential case 321 has a pair of left and right drive shaft through holes 321b that communicate with the housing portion 321a in the rotation axis direction of the differential case 321, i.e., the left-right direction, and through which the left drive shaft 325L and the right drive shaft 325R pass, and a pair of differential pinion shaft through holes 321c that communicate with the housing portion 321a and through which the differential pinion shaft 322 passes. The pair of differential pinion shaft through holes 321c are provided so as to communicate with the substantially center of the housing portion 321a in the rotation axis direction of the differential case 321, i.e., the left-right direction, and to be orthogonal to the rotation axis of the differential case 321.

[0088] Furthermore, the differential case 321 is provided with a fixing pin 400 (see FIG. 4 ) for fixing the differential pinion shaft 322 to the differential case 321. Figure 7 The fixing pin through hole 321d is provided so as to be parallel to the rotation axis of the differential case 321 and to be orthogonal to each of the pair of differential pinion shaft through holes 321c.

[0089] like Figure 7 As shown, the fixing pin 400 passes through the fixing pin through hole 321d of the differential case 321 and the fixing pin through hole 322a arranged near the end of the differential pinion shaft 322, thereby limiting the rotation of the differential pinion shaft 322 around an axis orthogonal to the rotation axis of the differential case 321 and the movement in the direction of the axis.

[0090] In this embodiment, if Figure 6 As shown, the fixing pin through hole 321d of the differential case 321 is provided at a position overlapping with any one of the pinion shaft through 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 directions. Figure 7 As shown, the left end portion 321dL of the fixing pin through hole 321d is connected to a pinion shaft through hole 316dR provided on the right wall portion 316b of the planetary carrier 316, and the right end portion 321dR of the fixing pin through hole 321d is connected to the outside of the differential case 321 on the opposite side of the planetary carrier 316.

[0091] According to the structure of this embodiment, when the fixing pin 400 that fixes the differential pinion shaft 322 to the differential case 321 is installed in the differential case 321, as shown in FIG. Figure 7 As shown by the arrow of the reference numeral α in FIG. 1 , the fixing pin 400 is inserted into the fixing pin through hole 321d from the right side of the differential case 321, thereby enabling the fixing pin 400 to be mounted on the differential case 321. In addition, when removing the fixing pin 400 mounted on the differential case 321, as shown in FIG. Figure 7 As shown by the arrow marked β in the figure, after the planetary pinion shaft 313 passing through the pinion shaft through hole 316dR connected to the fixing pin through hole 321d is properly removed, the fixing pin 400 in the fixing pin through hole 321d is pushed out to the right of the differential case 321 through the pinion shaft through hole 316dR, thereby making it easy to remove the fixing pin 400 from the differential case 321.

[0092] Therefore, according to the structure of the present embodiment, even if the differential pinion shaft 322 is removed 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 damaging the differential case 321, the fixing pin 400 and the differential pinion shaft 322, etc., and can be reused.

[0093] Furthermore, the pinion shaft through hole 316dR (i.e., the pinion shaft through hole 316d) connected to the fixing pin through hole 321d can be utilized as a hole used when the fixing pin 400 is pushed out of the differential case 321. Therefore, it is not necessary to provide an extra hole in the differential case 321 (a hole used only when the fixing pin 400 is pushed out of the differential case 321), thereby avoiding a reduction in the strength of the differential case 321 and the planetary carrier 316 due to the provision of such a hole.

[0094] Furthermore, according to the structure of the present embodiment, the fixing pin through hole 321d of the differential case 321 is communicated with the pinion shaft through hole 316d of the planetary carrier 316. Therefore, for example, when the planetary pinion shaft 313 is mounted on or removed from the planetary carrier 316, the fixing pin through hole 321d communicated with the pinion shaft through hole 316d through which the planetary pinion shaft 313 is passed functions as a so-called "air vent", making it easy to mount and remove the planetary pinion shaft 313. Similarly, when the fixing pin 400 is mounted on or removed from the differential case 321, the pinion shaft through hole 316d communicated with the fixing pin through hole 321d through which the fixing pin 400 is passed functions as an air vent, making it easy to mount and remove the fixing pin 400.

[0095] As described above, according to the present embodiment, even after the fixing pin 400 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 .

[0096] Above, an embodiment of the present invention has been described, but the present invention is certainly not limited to this embodiment. Obviously, those skilled in the art can think of various variations or modifications within the scope of the technical solution, and it should be understood that these variations and modifications also belong to the technical scope of the present invention. In addition, within the scope of not departing from the gist of the invention, the various constituent elements in the aforementioned embodiment can also be arbitrarily combined.

[0097] For example, when the differential pinion shaft 322 is fixed to the differential case 321 by one fixing pin 400, the number of the fixing pin through hole 321d may be one. Alternatively, even when the differential pinion shaft 322 is fixed to the differential case 321 by one fixing pin 400, the fixing pin through hole 321d may be one. Figure 6 Although a plurality of fixing pin through holes 321 d are provided as shown in the figure, there may actually be fixing pin through holes 321 d through which no fixing pin 400 passes.

[0098] In addition, in the example described above, four pinion shaft through holes 316d are provided at intervals of 90 degrees in the circumferential direction in the left wall portion 316a and the right wall portion 316b, respectively, but the present invention is not limited thereto. That is, as long as the fixing pin through hole 321d of the differential case 321 is provided at a position overlapping with any one of the pinion shaft through holes 316d provided in the planetary carrier 316 and communicating with the pinion shaft through hole 316d when the planetary carrier 316 and the differential case 321 are viewed from the left and right directions, the number of the pinion shaft through holes 316d is not limited to four.

[0099] As an example, Figure 8As shown in FIG. 1 , three pinion shaft through holes 316d are provided at intervals of 120 degrees in the circumferential direction on the left wall portion 316a and the right wall portion 316b. As another example, Fig. 9 As shown, five pinion shaft through holes 316d are provided in the left wall portion 316a and the right wall portion 316b at intervals of 72 degrees in the circumferential direction.

[0100] In addition, the number of differential pinion shafts 322 mounted on the differential case 321 is not limited to one, and two may be provided, for example. In this case, the fixing pin through hole 321d through which the fixing pin 400 fixing each differential pinion shaft 322 to the differential case 321 passes communicates with any of the pinion shaft through holes 316d.

[0101] In addition, for example, Figure 8 , Fig. 9 As shown in the figure, a dummy hole 316f is further provided at a position overlapping with the pinion shaft through hole 316d other than the pinion shaft through hole 316d communicated with the fixing pin through hole 321d when the differential case 321 is viewed from the left and right directions. In this case, similarly to the fixing pin through hole 321d, one end of the dummy hole 316f is communicated with the corresponding pinion shaft through hole 316d (pinion shaft through hole 316dR), and the other end of the dummy hole 316f is communicated with the outside of the differential case 321 on the opposite side to the planet carrier 316. By providing such a dummy hole 316f, the dummy hole 316f communicated with each pinion shaft through hole 316d functions as an exhaust hole, and the planetary pinion shaft 313 can be easily mounted and dismounted.

[0102] At least the following matters are described in this specification. In addition, in brackets, corresponding components and the like in the above-mentioned embodiment are shown, but the present invention is not limited to these.

[0103] (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), wherein:

[0104] The planetary gear mechanism has a planetary carrier (planetary carrier 316), and the planetary carrier has a pinion shaft through hole (pinion shaft through hole 316d), and the pinion shaft through hole is passed through by a planetary pinion shaft (planetary pinion shaft 313) that supports the planetary gears (stepped pinion 314, first planetary gear 314a, second planetary gear 314b).

[0105] The differential gear mechanism includes a differential case (differential case 321) supporting a differential pinion shaft (differential pinion shaft 322).

[0106] The differential case is formed integrally with the planetary carrier in a state where the differential case is aligned with the planetary carrier in the direction of the rotation axis of the differential case.

[0107] The differential housing has:

[0108] a differential pinion shaft through hole (differential pinion shaft through hole 321c) which is provided in a manner orthogonal to the rotation axis of the differential case and through which the differential pinion shaft passes; and

[0109] a fixing pin through hole (fixing pin through hole 321d) which is arranged in parallel with the rotation axis of the differential case and orthogonal to the differential pinion shaft through hole and through which a fixing pin passes, and the fixing pin fixes the differential pinion shaft passing through the differential pinion shaft through hole to the differential case,

[0110] The fixing pin through hole is arranged at a position overlapping with the pinion shaft through hole when the planetary carrier and the differential case are observed from the direction of the rotating axis, one end of the fixing pin through hole (the left end 321dL) is connected to the pinion shaft through hole, and the other end of the fixing pin through hole (the right end 321dR) is connected to the outside of the differential case on the opposite side of the planetary carrier.

[0111] According to (1), one end of the fixing pin through hole through which the fixing pin that fixes the differential pinion shaft to the differential case passes is connected to the pinion shaft through hole of the planetary carrier, and the other end of the fixing pin through hole is connected to the outside of the differential case on the opposite side of the planetary carrier. Therefore, by pushing the fixing pin in the fixing pin through hole to the outside of the differential case through the pinion shaft through hole of the planetary carrier, the fixing pin can be easily removed from the differential case.

Claims

1. A power transmission device comprising a planetary gear mechanism and a differential gear mechanism, wherein: The planetary gear mechanism includes a planet carrier, the planet carrier includes a pinion shaft through hole, and the pinion shaft through hole is passed through by a planet pinion shaft that supports the planetary gear. The differential gear mechanism includes a differential case supporting a differential pinion shaft. The differential case is formed integrally with the planetary carrier in a state where the differential case is aligned with the planetary carrier in the direction of the rotation axis of the differential case. The differential housing has: a differential pinion shaft through hole, which is provided in a manner perpendicular to the rotation axis of the differential case and through which the differential pinion shaft passes; and a fixing pin through hole, which is arranged in parallel with the rotation axis of the differential case and orthogonal to the differential pinion shaft through hole and through which a fixing pin passes, and the fixing pin fixes the differential pinion shaft passing through the differential pinion shaft through hole to the differential case, The fixing pin through hole is arranged at a position overlapping with the pinion shaft through hole when the planetary carrier and the differential case are viewed from the direction of the rotating axis, one end of the fixing pin through hole is connected to the pinion shaft through hole, and the other end of the fixing pin through hole is connected to the outside of the differential case on the opposite side of the planetary carrier.

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