JP2011185402A - Device of differential gear for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device of differential gear for a vehicle that prevents a lack of lubrication in a differential case. <P>SOLUTION: In a pinion shaft 93, an outer peripheral side end 130 is fixed on a second differential case 98 while an end face 126 of an inner peripheral side is separated from an axis C1 by a predetermined space A, and the pinion shaft has an oil storage hole 134 which is opened on the end face 126. Accordingly, lubricant, which is supplied from an oil pump 138 to the predetermined space A when the differential case 80 is rotated and which is blown off to the outer peripheral side due to centrifugal force, is partly supplied and stored in the oil storage hole 134. The lubricant stored in the oil storage hole 134 is maintained in the oil storage hole 134 even when an electric vehicle 12 stops, and is immediately supplied to respective side gears 92 and pinions 94 and the like within a time until the differential case 80 makes a half turn when the electric vehicle 12 starts. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to lubrication of a differential gear device for a vehicle.

  A differential case supported rotatably about a single axis, a pair of side gears housed in the differential case in a state of being opposed to each other in the direction of the single axis, and rotatably provided about the single axis; A plurality of pinions respectively housed in the differential case in a state of meshing with a pair of side gears and supported by a plurality of pinion shafts that are radially fixed to the differential case so as to be rotatable about the axis thereof, respectively. A differential gear device for vehicles is known. For example, it is described in Patent Document 1. The differential gear device for a vehicle described in Patent Document 1 is provided with an oil guide member for guiding oil, which has been scraped up by the rotation of the ring gear on the outer periphery of the differential case, into the differential case. The oil guided into the differential case by the oil guide member is used for lubricating side gears and pinions.

JP 59-140963 A

  By the way, when there is no space for providing the oil guide member as described above, for example, oil is supplied into the differential case by an oil pump. However, when the operation of the oil pump is limited to when the vehicle is traveling, it takes time until the oil is supplied into the differential case after the oil pump starts operating when the vehicle starts. There was a problem of insufficient lubrication in the differential case. The configuration in which the operation of the oil pump is limited when the vehicle is running is, for example, from a gear fixed to the outer periphery of a differential case or the like that stops rotating together with the drive wheels of the vehicle, or a drive source (electric motor) of an electric vehicle. A configuration in which the oil pump is rotationally driven by a rotating member for transmitting power to the drive wheels is applicable. On the other hand, it is conceivable that the differential case is configured to be oil-tight so that the oil is retained in the differential case even when the vehicle is stopped. With this configuration, the side gear and the pinion at the start of the vehicle There is a possibility that the adverse effect that the rotational resistance increases and the power transmission efficiency decreases.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle differential gear device capable of suppressing insufficient lubrication in the differential case.

  The gist of the invention according to claim 1 for achieving the object is as follows: (a) a differential case supported so as to be rotatable around a single axis, and the differential case in a state of being opposed to each other in the direction of the single axis. A pair of side gears housed in the shaft and rotatably provided around the uniaxial center, and a plurality of side gears housed in the differential case in a state of meshing with the pair of side gears and fixed in the radial direction to the differential case, respectively. A plurality of pinions supported by a pinion shaft so as to be rotatable about the axis thereof, and (b) the pinion shaft has an end surface on the inner peripheral side that is uniaxial. The outer peripheral end is fixed to the differential case in a state where a predetermined space is separated from the core, and has an oil reservoir hole that opens to the inner peripheral end face.

  Further, the gist of the invention according to claim 2 is that, in the invention according to claim 1, three or more pinion shafts are arranged at equal intervals in the circumferential direction around the one axis, When the rotation is stopped, the oil is stored in at least one of the oil storage holes of the three or more pinion shafts regardless of the circumferential stop position of the differential case.

  Further, the gist of the invention according to claim 3 is that, in the invention according to claim 1 or 2, the inner peripheral side end portions of the plurality of pinion shafts are annularly connected to the inner peripheral side with respect to the pinion. The members are connected to each other in a state where the inner peripheral side end faces of the pinion shaft are exposed.

  According to the differential gear device for a vehicle of the first aspect of the invention, the pinion shaft has the outer peripheral end fixed to the differential case with the inner peripheral end face spaced apart from the single axis by a predetermined space. Since the oil storage hole is opened at the inner peripheral end face, when the differential case is rotating, it is blown from the predetermined space to the outer peripheral side by centrifugal force and stored in the oil storage hole. Oil is retained in the oil reservoir hole even when the vehicle is stopped, and is supplied to the pinion, side gear, etc. immediately after starting the rotation of the differential case at the start of the vehicle, so that insufficient lubrication in the differential case is suppressed, especially when the vehicle starts can do.

  According to the differential gear device for a vehicle according to the second aspect of the present invention, when three or more pinion shafts are arranged at equal intervals in the circumferential direction around the one axis, and the rotation of the differential case is stopped. In this case, oil is stored in at least one of the oil storage holes of the three or more pinion shafts regardless of the circumferential stop position of the differential case, so that the lubricating oil flows out from the differential case after the vehicle stops. However, since the lubricating oil is reliably held in the oil storage hole of the pinion shaft, the oil is reliably supplied to the pinion and the side gear immediately after the start of the rotation of the differential case at the start of the vehicle. The shortage can be suppressed.

  According to the differential gear device for a vehicle of the invention according to claim 3, the inner peripheral side end portions of the plurality of pinion shafts are connected to the inner ends of the pinion shafts by the annular connecting member located on the inner peripheral side of the pinion. Since the peripheral end faces are connected to each other in an exposed state, both ends of the pinion shaft are supported by the differential case and the annular connecting member, so that the support rigidity of the pinion shaft is sufficiently secured and the pinion Since the end surface on the inner peripheral side of the shaft is exposed and the opening of the oil storage hole opens toward the uniaxial center, the lubricating oil is easily stored in the oil storage hole.

  Preferably, the vehicle differential gear device of the present invention is used when the operation of the oil pump is limited to when the vehicle is traveling. The configuration in which the operation of the oil pump is limited when the vehicle is running is, for example, a configuration in which the oil pump is rotationally driven by a member that stops rotating together with the driving wheels of the vehicle, for example, an annular gear fixed to the outer periphery of the differential case, Alternatively, the oil pump is driven to rotate by a rotating member for transmitting power from a drive source (electric motor) of the electric vehicle to the drive wheels. In this way, when the vehicle is stopped, the oil pump is not operating, the supply of oil into the differential case is stopped, and when the vehicle starts, the oil pump starts operating and the oil pump enters the differential case. Even if it takes time until the oil is supplied, since the oil is supplied from the oil storage hole before the oil is supplied from the oil pump, insufficient lubrication in the differential case can be suppressed.

It is a figure which shows notionally the structure of the drive system of a vehicle provided with the drive device for vehicles to which this invention was applied. FIG. 2 is a skeleton diagram illustrating the configuration of the vehicle drive device of FIG. 1. FIG. 3 is a cross-sectional view showing a specific configuration including a vehicle differential gear device according to an embodiment of the present invention in a section indicated by an arrow III in FIG. FIG. 4 is a cross-sectional view of the vehicle differential gear device showing a cross section taken along the line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the vehicle differential gear device showing a state in which the differential case has stopped rotating in a state where the differential case is rotated 60 degrees around the axis center compared to FIG. 4.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified for ease of explanation, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram conceptually showing a configuration of a drive system of an electric vehicle 12 including a vehicle drive device 10 to which the present invention is applied. In FIG. 1, an electric vehicle 12 includes a pair of left and right front wheels 14 and 16 provided on the front side and the rear side thereof, and a front side of the electric vehicle 12, and a pair of left and right drive shafts (axles) 22. And a vehicle drive device 10 that rotationally drives the pair of front wheels 14.

  The vehicle drive device 10 includes a drive unit 26 including an electric motor 24 that functions as a drive source of the electric vehicle 12 and is placed horizontally on the electric vehicle 12, and a pair of left and right drives while decelerating the output rotation of the drive unit 26. A transaxle portion 28 that functions as a power transmission device that distributes the shaft 22 is provided. The electric motor 24 is operated by a driving current supplied from an inverter (not shown) provided in the vehicle, for example. The electric vehicle 12 is an FF (front motor / front drive) type vehicle in which a front wheel 14 as a drive wheel is rotationally driven by an electric motor 24 disposed on the front side thereof.

  FIG. 2 is a skeleton diagram illustrating the configuration of the vehicle drive device 10 of FIG. In FIG. 2, the vehicle drive device 10 is housed in a three-part transaxle case 32 and disposed on a common axis C <b> 1, a speed reducer 34, and a vehicle differential gear device ( (Hereinafter referred to as a differential gear device) 36. The drive unit 26 is mainly configured by including an electric motor 24, and the transaxle unit 28 is mainly configured by including a speed reducer 34 and a differential gear device 36.

  The transaxle case 32 mainly accommodates a cylindrical case 38 that accommodates the electric motor 24, and mainly accommodates the reduction gear 34 and the differential gear device 36, and an end on the opening side is fixed to one end of the cylindrical case 38. The bottomed cylindrical case 44 and a disc-like case cover 48 fixed to the other end of the cylindrical case 38 are included. An oil pan 52 is fixed to an opening formed on the lower surface of the cylindrical case 38 so as to close the opening. The oil pan 52 functions as an oil receiver for receiving the lubricating oil circulating in the transaxle case 32 when it circulates in the lower part of the cylindrical case 38. The cylindrical case 38, the bottomed cylindrical case 44, and the case cover 48 are made of, for example, die-cast aluminum alloy.

  The electric motor 24 includes a stator 58 that is integrally fixed to an inner peripheral portion of the cylindrical case 38 with, for example, a bolt (not shown), a rotor 60 that is disposed on the inner peripheral side of the stator 58, and the above-described FIG. A motor side bearing 62 and a case cover which are provided on the outer peripheral side of one drive shaft 22 provided on the right side of the electric vehicle 12, the rotor 60 is fixed to the outer peripheral side, and both end portions are provided in the cylindrical case 38. And a cylindrical output shaft 64 rotatably supported by 63 arranged at 48. In the electric motor 24 configured as described above, the output shaft 64 is rotationally driven according to the drive current supplied from the inverter to the stator 58, and the input shaft 66 of the speed reducer 34 connected to the output shaft 64 is rotationally driven. To do.

  The speed reducer 34 is provided on the outer peripheral side of the one drive shaft 22 and is connected to an output shaft 64 of the electric motor 24 so as not to be relatively rotatable by, for example, spline fitting. It has a sun gear S that is fitted to the shaft end portion 68 on the opposite side of the motor 24, that is, the differential gear device 36 side so as not to be relatively rotatable by, for example, spline fitting, a small diameter portion 70, and a large diameter portion 72. A stepped pinion P having a diameter portion 72 meshed with the sun gear S, a carrier CA that supports the stepped pinion P so as to be able to rotate and revolve around the sun gear S via the pinion shaft 74, and concentric with the sun gear S A ring gear that is provided and fixed to the inner peripheral portion of the bottomed cylindrical case 44 so as not to rotate relative to the small diameter portion 70 of the stepped pinion P. And R, is a planetary gear type speed reducer provided.

  The carrier CA has a cylindrical end portion 78 on the side of the electric motor 24 supported by a first bearing 76 disposed in the bottomed cylindrical case 44 so as to be rotatable around an axis C1. Further, the carrier CA is connected to a differential case 80 of a differential gear device 36 disposed at a subsequent stage of the power transmission path of the speed reducer 34 and functions as an output member of the speed reducer 34.

  The input shaft 66 includes a parking lock gear 84 that protrudes from the outer peripheral surface to the outer peripheral side. The input shaft 66 is disposed on the inner peripheral side of the cylindrical end portion 78 and overlaps the first bearing 76 in the radial direction, and on the opposite side of the parking lock gear 84 from the second bearing 82. The third bearing 86 disposed on the bottomed cylindrical case 44 is provided so as to be concentric and relatively rotatable with respect to the carrier CA.

  The speed reducer 34 configured as described above reduces the rotational speed transmitted from the electric motor 24 to the input shaft 66 and outputs it to the differential gear device 36.

  FIG. 3 is a cross-sectional view showing a specific configuration of the portion indicated by the arrow III in FIG. 4 is a cross-sectional view showing a cross section taken along the line IV-IV in FIG. 2 to 4, the differential gear device 36 is housed in the differential case 80 in a state of being opposed to each other in the direction of the axial center C1, and a two-divided differential case 80 rotatably supported around the axial center C1. A pair of side gears 92 that are rotatably provided around the axis C1 and a differential case 80 that is disposed between the pair of side gears 92 at equal intervals in the circumferential direction around the axis C1 and meshes with the pair of side gears 92. Three pinions respectively accommodated in the inner case and rotatably supported around the axis C2 to C4 (see FIG. 4) of each pinion shaft 93 by three pinion shafts 93 fixed in the radial direction to the differential case 80, respectively. 94, and is provided adjacent to the opposite side of the input shaft 66 from the electric motor 24 in the direction of the axis C1.

  The differential case 80 is disposed on the opposite side of the first differential case 96 from the cylindrical first differential case 96 disposed on the input shaft 66 side in the direction of the axis C 1, and the first differential case 96. And a cylindrical second differential case 98 fastened to each other by bolts (not shown).

  The first differential case 96 is provided integrally with the carrier CA, and is supported by the first bearing 76 (see FIG. 2) via the carrier CA so as to be rotatable around the axis C1. The power of the speed reducer 34 is transmitted to the first differential case 96 through the carrier CA. The first differential case 96 functions as an input member of the differential gear device 36. In addition, an annular gear 102 for rotationally driving a driven gear 150 of an oil pump 138 described later is fixed to the outer peripheral surface of the first differential case 96. Further, as shown in FIG. 3, the first differential case 96 includes a cylindrical end portion 100 extending on the outer peripheral side of the shaft end portion 68 of the input shaft 66. An annular gap formed between the outer peripheral surface of the shaft end portion 68 of the input shaft 66 and the inner peripheral surface of the cylindrical end portion 100 is oil-tightly sealed to seal the gap inside the differential case 80. In addition, an oil seal 103 for storing lubricating oil up to an oil level L is provided. The oil seal 103 includes, for example, a metal annular cored bar 104 fitted to the inner peripheral surface of the cylindrical end portion 100, and a sealing made of, for example, a synthetic resin fixed to the inner peripheral side of the cored bar 104. And a member (lip) 106.

  The second differential case 98 is formed by a differential side bearing 114 in which a cylindrical end 116 extending on the opposite side of the first differential case 96 is disposed on the inner peripheral side of the bottom wall 112 of the bottomed cylindrical case 44. It is rotatably supported around the axis C1. The cylindrical end portion 116 is formed with an oil passage 118 communicating with the internal space of the differential case 80 that constitutes a part of a discharge oil passage 144 of a lubricating oil supply device 136 described later.

  Of the pair of side gears 92, the side gear 92 on the input shaft 66 side is connected to the inner peripheral side thereof so that the shaft end portion of the one drive shaft 22 cannot be relatively rotated by, for example, spline fitting. Further, of the pair of side gears 92, the side gear 92 opposite to the input shaft 66 is connected to the inner peripheral side thereof so that the shaft end of the other drive shaft 22 cannot be relatively rotated by, for example, spline fitting. The one drive shaft 22 is supported by the inner peripheral surface of the input shaft 66 so as to be rotatable around the axis C 1, and the other drive shaft 22 is connected to the cylindrical end 116 of the second differential case 98. The inner peripheral surface is supported so as to be rotatable around the axis C1.

  The three pinion shafts 93 are bottomed cylindrical members disposed at equal intervals in the circumferential direction around the axis C1 and in the radial direction orthogonal to the axis C1, that is, in the directions of the axes C2 to C4. Each pinion shaft 93 is located between the pair of side gears 92 and any one of three fitting holes 122 formed at equal intervals in the circumferential direction in the annular connecting member 120 located on the inner peripheral side of each pinion 94. The inner peripheral side end portions 124 are fitted to each other, and are connected to each other by the annular connecting member 120 with the inner peripheral side end face 126 exposed. Further, the three pinion shafts 93 are fitted to the outer peripheral side end portions 130 in any one of the three fitting holes 128 formed in the first differential case 96 at equal intervals in the circumferential direction. By providing the fixing pin 132 through the side end portion 130, the fixing pin 132 is fixed to the first differential case 96 in the radial direction and fixed so as not to move in the directions of the axes C2 to C4. The opposite ends of the pair of drive shafts 22 are fitted into the inner peripheral sides of both ends of the annular connecting member 120 in the direction of the axis C1 so as to be relatively rotatable with a predetermined space A therebetween. The three pinion shafts 93 are provided in a state in which the end surface 126 on the inner peripheral side is separated from the axis C1 by a predetermined space A. The three pinion shafts 93 have oil storage holes 134 that open to the end surface 126 on the inner peripheral side. The oil reservoir hole 134 is a hole having substantially the same diameter and drilled in the longitudinal direction of the pinion shaft 93, and is provided as deep as possible within a range not reaching the fixing pin 132 of the outer peripheral side end portion 130. The oil reservoir hole 134 is formed, for example, by machining the inner peripheral end face 126 of the pinion shaft 93 or when the pinion shaft 93 is molded by casting or sintering. Formed simultaneously.

  The differential gear device 36 configured as described above is driven to rotate by the speed reducer 34, thereby allowing the pair of drive shafts 22 disposed on the shaft center C1 to allow the rotational difference therebetween while driving force. To communicate.

  The vehicle drive device 10 lubricates each lubrication site of the motor 24, the speed reducer 34, and the differential gear device 36 configured as described above, for example, a gear meshing site or between two relatively rotating members. A lubricating oil supply device 136 for supplying oil (hereinafter referred to as lubricating oil) is provided. As shown in FIG. 2, the lubricating oil supply device 136 is stored in an internal gear type oil pump 138 fixed to the bottom surface inside the bottom wall 112 of the bottomed cylindrical case 44 and the oil pan 52. A suction oil passage 142 for guiding the lubricating oil to the oil pump 138 through the strainer 140, and a lubricant oil sucked and pressurized by the oil pump 138 through the suction oil passage 142 to the respective lubrication sites. And a discharge oil passage 144 that branches into a plurality on the way.

  In FIG. 3, the discharge oil passage 144 opens to the bottom surface of the bottom wall 112 of the bottomed cylindrical case 44 and communicates with the pump chamber of the oil pump 138, and the oil at the cylindrical end portion 116 of the second differential case 98. A first discharge oil passage (not shown) communicated with the passage 118, the oil passage 118, the inner space of the differential case 80, the inner peripheral surface of the input shaft 66, and the outer peripheral surface of the one drive shaft 22; It is composed of a cylindrical gap that communicates with the internal space of the differential case 80. In addition to the above, the discharge oil passage 144 is supplied with, for example, an oil passage for supplying lubricating oil to the electric motor 24 and a gear engagement portion of each rotating element of the speed reducer 34. Oil passages are included.

  3 and 4, the oil pump 138 includes a pump body 146 fixed to the bottom wall 112 of the bottomed cylindrical case 44 by, for example, a bolt, and the pump body 146 while being provided through the pump body 146. A pump shaft 148 rotatably supported by the shaft, a driven gear 150 fixed to the end of the pump shaft 148 so as not to rotate relative to the annular gear 102 provided in the first differential case 96, and a pump body 146 And a rotor (not shown) that rotates together with the pump shaft 148.

  In the lubricating oil supply device 136 configured as described above, the driven gear 150 is rotationally driven by the annular gear 102 as the differential case 80 of the differential gear device 36 is rotated by the power of the electric motor 24, and the oil pump. 138 is activated. When the rotor rotates together with the driven gear 150, the lubricating oil stored in the oil pan 52 is sucked into the pump chamber of the pump body 146 via the suction oil passage 142 and pressurized. The lubricating oil is pumped to each lubricating part through the discharge oil passage 144.

  As indicated by the dashed arrows in FIG. 3, the lubricating oil discharged from the pump chamber of the oil pump 138 and supplied to the oil passage 118 is pumped to the internal space of the differential case 80. The lubricating oil supplied to the space between the differential case 80 and each side gear 92 and each pinion 94 lubricates each side gear 92 and each pinion 94, while the inner peripheral surface of the input shaft 66 and the one drive It is supplied to other lubrication sites through the cylindrical gap formed between the outer peripheral surface of the shaft 22. Further, as indicated by a broken line arrow in FIG. 3, the inner peripheral surface of the side gear 92 opposite to the input shaft 66 with respect to the annular coupling member 120 of the pair of side gears 92 from the oil passage 118 and the other drive shaft. The lubricating oil supplied to the predetermined space A on the inner peripheral side of the annular coupling member 120 through the outer peripheral surface of the annular connecting member 120 is blown to the outer peripheral side by centrifugal force, and the lubricating oil stored in the differential case 80 is scraped up. A part of the oil is stored in the oil storage hole 134 of each pinion shaft 93 or supplied between each side gear 92 and each pinion 94 to lubricate them.

  Note that the oil pump 138 of the present embodiment is an annular ring fixed to the outer peripheral side of a differential case 80 that is a rotating member for transmitting power from the electric motor (drive source) 24 to the front wheels (drive wheels) 14 of the electric vehicle 12. It is of a type that is driven to rotate by the gear 102 and is operated only when the electric vehicle 12 is traveling. Therefore, when the traveling of the electric vehicle 12 is stopped, the supply of lubricating oil to the internal space of the differential case 80 by the oil pump 138 is stopped. In that case, the lubricating oil in the inner space of the differential case 80 located at a height exceeding the oil level L indicated by the one-dot chain line in FIG. 3 is the inner peripheral surface of the input shaft 66 and the outer peripheral surface of the one drive shaft 22. Is supplied to another lubricating part through the cylindrical gap formed between the two. Then, the lubricating oil positioned below the oil level L is held in the differential case 80 immediately after the electric vehicle 12 stops traveling, but after a while, in the oil storage hole 134 of the pinion shaft 74 as shown in FIG. Other than the accumulated lubricating oil, for example, flows out of the differential case 80 through a gap between the fitting hole 128 of the first differential case 96 and the pinion shaft 93. When the rotation of the differential case 80 is stopped, the pinion shaft 93 of this embodiment is provided in at least one of the oil storage holes 134 of the three pinion shafts 93 regardless of the circumferential stop position of the differential case 80. Oil can be stored. FIG. 5 shows a state where the rotation of the differential case 80 is stopped in a state where it is rotated 60 degrees around the axis C1 as compared with FIG. In the case shown in FIG. 5, the lubricating oil is stored in two of the oil storage holes 134 of the three pinion shafts 93. Although it takes time for oil to be supplied to the internal space of the differential case 80 after the oil pump 138 starts operating when the electric vehicle 12 starts, the internal space of the differential case 80 after the electric vehicle 12 stops as described above. Even if the lubricating oil flows out from the lubricating oil, the lubricating oil retained and retained in the oil reservoir hole 134 is immediately supplied to each side gear 92 and the pinion 94 within the time until the differential case 80 makes a half rotation when the electric vehicle 12 starts. Is done. When the electric vehicle 12 is started, since there is no lubricating oil other than the oil reservoir hole 134 in the differential case 80, the side gear 92, the pinion 94, and the like are smoothly rotated.

  As described above, according to the differential gear device 36 of the present embodiment, the pinion shaft 93 is in a state in which the end surface 126 on the inner peripheral side separates the predetermined space A with respect to the axis (one axis) C1. Since the outer peripheral side end portion 130 is fixed to the second differential case (difference case) 98 and has an oil storage hole 134 that opens to the inner peripheral end surface 126, the oil pump is rotated when the differential case 80 is rotating. A part of the lubricating oil that is supplied from 138 to the predetermined space A and is blown to the outer peripheral side by centrifugal force is supplied and stored in the oil storage hole 134. The lubricating oil stored in the oil storage hole 134 is held in the oil storage hole 134 even when the electric vehicle 12 is stopped, and immediately within the time until the differential case 80 makes a half rotation when the electric vehicle 12 starts. Supplied to each side gear 92 and pinion 94 and the like. Therefore, in particular, when the electric vehicle 12 is started, insufficient lubrication in the differential case 80 can be suppressed.

  Further, according to the differential gear device 36 of the present embodiment, when the rotation of the differential case 80 is stopped, the pinion shaft 93 has three pinion shafts regardless of the circumferential stop position of the differential case 80. Since the oil is stored in at least one of the oil storage holes 134 of the 93, even if the lubricating oil flows out from the internal space of the differential case 80 after the electric vehicle 12 is stopped, the lubricating oil is reliably retained in the oil storage hole 134. Therefore, the oil is reliably supplied to the pinion 94, the side gear 92, and the like immediately after the rotation of the differential case 80 when the electric vehicle 12 starts.

  Further, according to the differential gear device 36 of the present embodiment, the three pinion shafts 93 are circumferentially connected to the annular coupling member 120 located between the pair of side gears 92 and on the inner peripheral side of each pinion 94. The inner peripheral side end portions 124 are respectively fitted to any one of the three fitting holes 122 formed at intervals, and the inner end surface 126 is exposed by the annular connecting member 120. It is connected. Further, the three pinion shafts 93 are fitted to the outer peripheral side end portions 130 in any one of the three fitting holes 128 formed in the first differential case 96 at equal intervals in the circumferential direction. Since the fixing pin 132 is provided through the side end portion 130, the fixing pin 132 is fixed to the first differential case 96 in the radial direction and is fixed so as not to rotate around the respective axis C2 to C4. Therefore, both ends of the pinion shaft 93 are supported by the first differential case 96 and the annular coupling member 120, and sufficient support rigidity is secured, and the end surface 126 on the inner peripheral side of the pinion shaft 93 is exposed and the oil is removed. Since the opening of the reservoir hole 134 opens toward the axis C1, the lubricating oil is easily stored in the oil reservoir hole 134.

  Further, according to the differential gear device 36 of the present embodiment, the operation of the oil pump 138 is limited to when the electric vehicle 12 is traveling, and when the traveling of the electric vehicle 12 is stopped, the oil pump 138 moves to the internal space of the differential case 80. Even if it takes time until the oil pump 138 starts operating when the electric vehicle 12 starts and the lubricating oil is supplied from the oil pump 138 into the differential case 80 because the supply of the lubricating oil stops. Since the lubricating oil is immediately supplied from the oil storage hole 134 of the pinion shaft 93 to each side gear 92 and the pinion 94 within the time until the differential case 80 makes a half rotation when the electric vehicle 12 is started, the lubrication in the differential case 80 is preferably insufficient. Can be suppressed.

  As mentioned above, although one Example of this invention was described in detail with reference to drawings, this invention is not limited to this Example, It can implement in another aspect.

  For example, although the three pinion shafts 93 are provided at equal intervals around the axis C1, other numbers may be used. For example, if three or more are provided, the oil is stored in at least one of the plurality of oil storage holes 134 regardless of the circumferential stop position of the differential case 80.

  Further, the differential case 80 may be divided or non-divided, that is, integrally molded.

  The plurality of pinion shafts 93 may be integrally formed, for example, in addition to being connected to each other by the annular connecting member 120. In short, it is only necessary that the end surface 126 on the inner peripheral side of each pinion shaft 93 is provided with a predetermined space A with respect to the axis C1. The size of the predetermined space A is not limited. If it is the magnitude | size which can supply lubricating oil to the predetermined space A, that is sufficient.

  Further, the shape of the oil reservoir hole 134 formed in the pinion shaft 93 is not limited to that of the above-described embodiment. For example, a stepped shape or a tapered shape may be used, and a cross section in a direction orthogonal to the axis of the pinion shaft 93 may be a circle or a polygon. In short, it is only necessary to form a space in which lubricating oil is stored.

  Further, the differential gear device 36 is not limited to the electric vehicle 12 and can be suitably used even for a vehicle including a drive source such as an engine, for example.

  Further, the differential gear device 36 is not limited to the vehicle drive device 10 for the FF vehicle, and for example, a drive device for a vehicle that employs another drive format such as for FR vehicles, MR vehicles, and RR vehicles. Even can be used. Further, the present invention can be applied not only to a two-wheel drive vehicle but also to a four-wheel drive vehicle, for example.

  It should be noted that the above description is merely an embodiment, and other examples are not illustrated. However, the present invention is implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the gist of the present invention. Can do.

36: differential gear device for vehicle 80: differential case 92: side gear 93: pinion shaft 94: pinion 120: annular coupling member 124: inner peripheral end 126: inner peripheral end surface 130: outer peripheral end 134: oil storage Hole A: Predetermined space C1: Axes C2 to C4: Pinion shaft axis

Claims (3)

A differential case supported rotatably around a single axis, a pair of side gears housed in the differential case in a state of being opposed to each other in the direction of the single axis, and rotatably provided around the single axis; A plurality of pinions respectively housed in the differential case in mesh with a pair of side gears and supported by a plurality of pinion shafts fixed to the differential case in a radial direction so as to be rotatable around the axis of the pinion shaft; A vehicle differential gear device comprising:
The pinion shaft has an oil reservoir hole that is fixed to the differential case at an outer peripheral end with an inner peripheral end face spaced apart from the uniaxial center and that opens to the inner peripheral end face. A vehicle differential gear device characterized by comprising:   Three or more pinion shafts are arranged at equal intervals in the circumferential direction around the one axis, and when the rotation of the differential case is stopped, the three pinion shafts, regardless of the circumferential stop position of the differential case, 2. The vehicle differential gear device according to claim 1, wherein oil is stored in at least one of the oil storage holes of the pinion shaft or more.   Inner circumferential side end portions of the plurality of pinion shafts are connected to each other by an annular coupling member located on the inner circumferential side of the pinion with the inner circumferential side end surface of the pinion shaft exposed. The differential gear device for a vehicle according to claim 1 or 2.

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