Vehicle differential device

Abstract

To provide a vehicle differential device capable of discharging gas generated when welding a differential case and a differential ring gear even if performing laser welding while a pinion shaft and a pinion shaft fixing pin are attached to the differential case in advance.SOLUTION: A vehicle differential device 1 is equipped with a fitting portion 51 where a differential case 3 and a differential ring gear 2 are fitted, and a welding portion 52 that is welded between the differential case 3 and the differential ring gear 2, on the outer side than the fitting portion 51. The differential case 3 is provided with a hollow pinion shaft fixing pin 60 that extends through an insertion hole 44 so as to penetrate one end of a pinion shaft 42 on the inner side of the fitting portion 51. The pinion shaft fixing pin 60 is provided with a through-hole 63 with a predetermined size, at an axial position opposite to the other end of a communication path 54 opening to a space portion 53 at one end and opening to the insertion hole 44 at the other end.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a differential device for a vehicle. [Background technology]

[0002] 2. Description of the Related Art A so-called FR (front engine, rear drive) based vehicle is known in which a drive source such as an engine and a transmission are arranged at the front of the vehicle body with their axes extending in the fore-and-aft direction of the vehicle body, and driving force transmitted from the transmission is transmitted from a rear wheel output shaft extending toward the rear of the vehicle body to the rear wheels as the main drive wheels, via a rear wheel propeller shaft and a rear wheel differential device.

[0003] The rear wheel differential device (hereinafter referred to as the differential device) installed in such a vehicle is configured to distribute the driving force transmitted from the rear wheel propeller shaft (hereinafter referred to as the propeller shaft) to the corresponding left and right drive wheels, for example, when the vehicle turns, thereby adjusting the difference in wheel rotation speed that occurs between the left and right drive wheels.

[0004] This differential device includes a differential ring gear to which driving force is transmitted from the propeller shaft, and a differential case that is joined to the differential ring gear by screwing or welding and rotates together with the differential ring gear. The differential case is provided with a pair of left and right side gears that distribute the driving force transmitted from the differential ring gear to the left and right drive wheels, a pinion shaft that extends in a direction perpendicular to the differential ring gear, and a pinion gear that is provided on the pinion shaft and meshes with the pair of left and right side gears to adjust the difference in wheel rotation speed generated between the drive wheels.

[0005] As a method for joining a differential ring gear and a differential case, for example, laser welding is known in which a laser is irradiated to a weld where a differential ring gear made of carbon steel and a differential case made of cast iron are welded to join the differential ring gear and the differential case.

[0006] The welded portion where the differential ring gear and the differential case are in contact is provided with a groove having a groove that opens toward the outside. When performing laser welding, filler is supplied from the outside to the groove and a laser is irradiated, so that molten metal forms a weld bead in the groove. At this time, gas is generated from a part of the molten metal due to the heat of the laser, and the pressure of the gas may damage the welded portion. Therefore, it is necessary to provide a communication passage that connects the welded portion to the outside so as to suppress the increase in the pressure of the gas generated in the welded portion.

[0007] For example, Patent Document 1 discloses a welding structure in which a differential case has an insertion hole into which a pinion shaft fixing pin is inserted to fix a pinion shaft, and a communication passage is provided that connects the insertion hole to a welded portion, so that when laser welding is performed, gas generated from the welded portion is exhausted through the communication passage.

[0008] Patent Document 1 also discloses a welding structure in which the communication passage is blocked by inserting a pinion shaft fixing pin into the insertion hole after laser welding is completed, which makes it possible to prevent a portion of the molten metal, such as spatter, from being discharged to the outside. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6196271 Summary of the Invention [Problem to be solved by the invention]

[0010] On the other hand, in the welding structure of Patent Document 1, when laser welding is performed, gas generated in the welded portion cannot be discharged to the outside when the pinion shaft fixing pin is inserted into the insertion hole, so laser welding must be performed before attaching the pinion shaft and the pinion shaft fixing pin. Therefore, it is difficult to apply the welding structure of Patent Document 1 to a differential device that is assembled by attaching the pinion shaft and the pinion shaft fixing pin to the differential case before performing laser welding. For example, when the differential ring gear has a structure in which it overlaps with the pinion shaft assembled to the differential case in the axial direction of the differential ring gear, it may be necessary to join the differential case and the differential ring gear after assembling the pinion shaft and the pinion shaft fixing pin to the differential case.

[0011] Therefore, an object of the present invention is to provide a differential device for a vehicle that can exhaust gas generated when welding the differential case and the differential ring gear, even when laser welding is performed with the pinion shaft and pinion shaft fixing pin already attached to the differential case. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention is characterized by having the following configuration.

[0013] First, the invention described in claim 1 of the present application is a differential device for a vehicle including a fitting portion where an outer peripheral side surface of a differential case and an inner peripheral side surface of a differential ring gear are fitted together, and a weld portion that is welded between the differential case and the differential ring gear on the outer side of the fitting portion, The differential case is provided with a pinion shaft extending in a direction perpendicular to the axis of the differential ring gear on the inside of the fitting portion, an insertion hole extending to intersect with the pinion shaft and communicate with the outside, and a hollow pinion shaft fixing pin extending through the insertion hole to penetrate one end of the pinion shaft in order to fix the pinion shaft. The differential case is provided with a communication passage having one end opening toward the welded portion and the other end opening into the insertion hole, The pinion shaft fixing pin has a through hole of a predetermined size at an axial position opposite to the other end of the communication passage. R, The pinion shaft fixing pin has a communication passage facing portion that faces the other end of the communication passage, and the through hole is provided in the communication passage facing portion. It is characterized by:

[0014] The invention as set forth in claim 2 is characterized in that in the invention as set forth in claim 1, the pinion shaft fixing pin has a cylindrical portion that extends in a cylindrical shape.

[0015] The invention recited in claim 3 is characterized in that in the invention recited in claim 2, the through hole is provided around the entire circumference of the pinion shaft fixing pin.

[0016] The invention described in claim 4 is the invention described in claim 3, wherein the pinion shaft fixing pin is provided with a narrowed portion recessed from the outside toward the inside at a position facing the other end of the communication passage, The through hole is characterized in that it is provided in the narrowed portion.

[0017] Further, the invention described in claim 5 is the invention described in claim 1, wherein the pinion shaft fixing pin has a C-shaped open tubular portion extending along an axial direction of the pinion shaft fixing pin and having an opening formed by cutting out a part of a side surface in a circumferential direction, The pinion shaft fixing pin is characterized in that the opening is disposed on a radially opposite side to the other end of the communication passage of the differential case.

[0018] The invention described in claim 6 is characterized in that, in the invention described in claim 5, the pinion shaft fixing pin is positioned so that the opening is located radially opposite the other end of the communicating passage of the differential case using a positioning tool having a pin fitting portion that is inserted into the opening. Effect of the Invention

[0019] According to the invention described in claim 1 of the present application, when the differential case and the differential ring gear are fitted and welded, the gas generated from the welded portion flows through the communication passage toward the insertion hole of the differential case. At this time, the gas can be discharged from the through hole through the inside of the hollow pinion shaft fixing pin to the outside by the through hole of a predetermined size provided in the pinion shaft fixing pin that is inserted in advance into the insertion hole. In addition, spatter larger than the through hole generated during welding does not enter the inside of the pinion shaft fixing pin. With a simple configuration in which a communication passage is provided in the differential case and a through hole of a predetermined size is provided in the pinion shaft fixing pin, only the gas can be discharged to the outside. Therefore, even when laser welding is performed with the pinion shaft and the pinion shaft fixing pin attached to the differential case in advance, a vehicle differential device that can discharge the gas generated during welding of the differential case and the differential ring gear can be provided.

[0020] Furthermore, according to the invention as set forth in claim 2 of the present application, the pinion shaft fixing pin has a cylindrical portion that extends cylindrically, so that gas can pass through the inside of the cylindrical portion and be easily discharged to the outside.

[0021] Furthermore, according to the invention described in claim 3 of the present application, since the through holes are provided around the entire circumference of the pinion shaft fixing pin, there is no need to position the pinion shaft fixing pin in the circumferential direction, and the pinion shaft fixing pin can be easily attached to the insertion hole.

[0022] Furthermore, according to the invention described in claim 4 of the present application, since a through hole is provided in the narrowed portion of the pinion shaft fixing pin, gas can pass through the gap between the insertion hole and the narrowed portion, through the through hole, and through the inside of the cylindrical portion to be easily discharged to the outside.

[0023] According to the invention as set forth in claim 5 of the present application, the pinion shaft fixing pin has a C-shaped cylindrical opening, so that the pinion shaft fixing pin can be easily assembled into the insertion hole by reducing its diameter.

[0024] Furthermore, according to the invention described in claim 6 of the present application, the pinion shaft fixing pin can be easily positioned in the circumferential direction by attaching the pinion shaft fixing pin to the insertion hole with the pin fitting portion of the positioning tool inserted into the opening of the pinion shaft fixing pin. [Brief description of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing a differential gear according to an embodiment of the present invention. [Diagram 2] 2 is a schematic diagram showing a pinion shaft fixing pin disposed in the differential device of FIG. 1. [Diagram 3] FIG. 13 is a schematic view showing a pinion shaft fixing pin according to another embodiment. [Figure 4] FIG. 13 is a schematic view showing a pinion shaft fixing pin according to another embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing the pinion shaft fixing pin and a positioning tool in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0027] Fig. 1 is a schematic diagram showing a differential device according to an embodiment of the present invention. As shown in Fig. 1, a vehicle differential device 1 according to the embodiment of the present invention is configured as a rear wheel differential device for a front engine / rear drive vehicle.

[0028] The differential device 1 includes a differential ring gear 2 configured as a bevel gear made of carbon steel, and a differential case 3 made of cast iron. The differential ring gear 2 includes a substantially cylindrical inner peripheral side surface 21 and an annular bottom surface 22 provided on one axial end side of the inner peripheral side surface 21 of the differential ring gear 2. In addition, on the other axial end side of the differential ring gear 2, bevel teeth 25 are provided that incline toward the one axial end side of the differential ring gear 2 as they move outward. On the other hand, the differential case 3 includes a substantially cylindrical outer peripheral side surface 31 having an outer diameter equivalent to that of the inner peripheral side surface 21 so as to fit with the inner peripheral side surface 21 of the differential ring gear 2, and an approximately spherical internal space 32 formed inside the outer peripheral side surface 31. In addition, on one axial end side of the outer peripheral side surface 31 of the differential case 3, a substantially circular flange 33 having a diameter equivalent to that of the bottom surface 22 of the differential ring gear 2 and a substantially cylindrical shaft portion 34 having a diameter smaller than that of the outer peripheral side surface 31 are provided.

[0029] A case-side inclined portion 35 is provided at a radial end of the flange 33 of the differential case 3, inclining toward one axial end of the differential case 3 as it moves outward. Meanwhile, a gear-side inclined portion 23 is provided at a radial end of the bottom surface 22 of the differential ring gear 2, inclining toward the opposite side to the case-side inclined portion 35 of the differential case 3 as it moves outward, and having a radial width equivalent to that of the case-side inclined portion 35.

[0030] Further, a bottom surface 22 of the differential ring gear 2 is provided with a recess 24 that is recessed in an annular shape toward the other axial end side of the differential ring gear 2, on the inside of the gear side inclined portion 23.

[0031] Further, in the differential case 3, on the inside of the outer peripheral side surface 31, a shaft hole 41 extending in a direction perpendicular to the axis of the outer peripheral side surface 31 so as to pass through the internal space 32, a pinion shaft 42 attached to extend through the shaft hole 41 and having a pin insertion hole 43 on the radial end side of the differential case 3, an insertion hole 44 extending and connecting with the pin insertion hole 43 so as to intersect with the pinion shaft 42 and communicate with the outside, and a hollow pinion shaft fixing pin 60 extending through the insertion hole 44 so as to penetrate the pinion shaft 42 through the pin insertion hole 43 at the radial end side of the differential case 3 in order to fix the pinion shaft 42 are provided. A pinion gear (not shown) housed in the internal space 32 is connected to this pinion shaft 42.

[0032] When the differential ring gear 2 and the differential case 3 are joined, the inner peripheral side surface 21 of the differential ring gear 2 is press-fitted into the outer peripheral side surface 31 of the differential case 3 to form a fitting portion 51. In addition, the bottom surface 22 of the differential ring gear 2 abuts against the flange 33 of the differential case 3 to form a welded portion 52 having a groove that opens outward between the gear side inclined portion 23 and the case side inclined portion 35, and a space portion 53 that expands in an annular shape surrounded by the recess 24, the outer peripheral side surface 31, and the flange 33 between the fitting portion 51 and the welded portion 52.

[0033] In addition, when the inner peripheral side surface 21 of the differential ring gear 2 and the outer peripheral side surface 31 of the differential case 3 are press-fitted and fitted to each other, the bevel teeth 25 of the differential ring gear 2 overlap with the shaft hole 41 and the pinion shaft 42 of the differential case 3 in the axial direction of the differential ring gear 2 and the differential case 3. Therefore, before the inner peripheral side surface 21 of the differential ring gear 2 and the outer peripheral side surface 31 of the differential case 3 are press-fitted and fitted to each other, the pinion shaft 42 is attached to the shaft hole 41 of the differential case 3, and the pinion shaft fixing pin 60 is attached to the insertion hole 44 via the pin insertion hole 43. Thereafter, in a state in which the inner peripheral side surface 21 of the differential ring gear 2 and the outer peripheral side surface 31 of the differential case 3 are press-fitted and fitted to each other, laser welding is performed on the welded portion 52 of the differential ring gear 2 and the differential case 3.

[0034] Further, the differential case 3 is provided with a communication passage 54, one end of which opens into the space 53 and the other end of which opens into the insertion hole 44. The communication passage 54 has a cylindrical shape with a diameter of 1.5 mm to 2 mm, although this is not limited thereto.

[0035] The pinion shaft fixing pin 60, which is arranged to pass through the insertion hole 44, is provided at the same position as the other end of the communicating passage 54 in the axial direction of the differential ring gear 2 and the differential case 3, and has a communicating passage opposing portion 61 on its side that faces the other end of the communicating passage 54.

[0036] Fig. 2 is a schematic diagram showing a pinion shaft fixing pin 60 disposed in the differential gear 1 of Fig. 1. In particular, Fig. 2(a) shows a side view of the pinion shaft fixing pin 60, while Fig. 2(b) shows a top view of the pinion shaft fixing pin 60. As shown in Fig. 2, the pinion shaft fixing pin 60 has a cylindrical portion 62 that extends straight in a cylindrical shape.

[0037] A plurality of through holes 63 are provided around the entire circumference of the cylindrical portion 62 at the communicating passage facing portion 61 of the pinion shaft fixing pin 60. These through holes 63 are set to a predetermined size that prevents some of the molten metal, such as spatter generated at the welded portion 52, from passing through. In the embodiment, the through holes 63 are arranged to form three rows along the axial direction of the pinion shaft fixing pin 60, and each has a diameter of 0.3 mm to 0.5 mm as the predetermined size, although this is not limited to this.

[0038] The through hole 63 provided in the pinion shaft fixing pin 60 is formed by, for example, but not limited to, laser processing in which a hole is opened by laser irradiation, electric discharge processing in which a hole is opened by arc discharge, or etching processing in which a hole is opened by a corrosive liquid.

[0039] Returning to Fig. 1, when the differential ring gear 2 and the differential case 3 are welded together, the shaft portion 34 of the differential case 3 is fixed to a fixture 102 which is rotationally driven by a motor 101. The motor 101 is electrically connected to an externally disposed controller 103 so that the rotational drive is controlled.

[0040] A pinion shaft 42 inserted into the shaft hole 41 and a pinion shaft fixing pin 60 inserted into the insertion hole 44 are attached to the differential case 3. At this time, the pinion shaft fixing pin 60 is appropriately positioned in the axial direction of the differential ring gear 2 and the differential case 3 so that a communication passage facing portion 61 of the pinion shaft fixing pin 60 faces the other end of the communication passage 54.

[0041] The inner peripheral side surface 21 of the differential ring gear 2 is press-fitted into the outer peripheral side surface 31 of the differential case 3 fixed to the fixing tool 102, forming a fitting portion 51. At this time, the bottom surface 22 of the differential ring gear 2 abuts against the flange 33 of the differential case 3, forming a welded portion 52 having a groove that opens outward between the gear side inclined portion 23 and the case side inclined portion 35. In addition, between the fitting portion 51 and the welded portion 52, a space portion 53 is formed that is surrounded by the recess 24 of the differential ring gear 2 and the outer peripheral side surface 31 and flange 33 of the differential case 3 and expands in an annular shape.

[0042] A laser torch 104 is disposed outside the welded portion 52 so that a laser can be incident straight on the groove of the welded portion 52. This laser torch 104 is electrically connected to a controller 103 so that the irradiation of the laser on the welded portion 52 is controlled. In addition, a filler supply unit 105 is disposed near the laser torch 104 so that a filler can be supplied to the groove of the welded portion 52. This filler supply unit 105 is electrically connected to the controller 103 so that the supply of filler to the welded portion 52 is controlled.

[0043] When the differential ring gear 2 and the differential case 3 arranged as described above are welded together, the motor 101 is rotationally driven based on an electrical signal transmitted from the controller 103. At this time, the differential case 3 fixed to the fixture 102 via the shaft portion 34 and the differential ring gear 2 fitted to the differential case 3 at the fitting portion 51 rotate together with the fixture 102 rotated by the motor 101.

[0044] Based on an electrical signal transmitted from the controller 103, filler is supplied from the filler supply unit 105 to the welded portion 52 of the rotating differential ring gear 2 and the differential case 3, and a laser is irradiated from the laser torch 104. The filler is melted by the laser irradiated from the laser torch 104 to form a weld bead at the welded portion 52, thereby welding the differential ring gear 2 and the differential case 3. As the differential ring gear 2 and the differential case 3 rotate, the position of the welded portion 52 to which the laser is irradiated moves in the circumferential direction, and laser welding is performed over the entire circumference of the differential ring gear 2 and the differential case 3.

[0045] Gas is generated from a portion of the molten metal at the welded portion 52. This gas flows toward the insertion hole 44 through the space portion 53 and the communication passage 54, and enters the inside of the pinion shaft fixing pin 60 through a through hole 63 provided in the communication passage facing portion 61 of the pinion shaft fixing pin 60 inserted into the insertion hole 44. The gas that reaches the inside of the pinion shaft fixing pin 60 moves along the axial direction of the cylindrical portion 62 of the pinion shaft fixing pin 60, and is discharged to the outside from the end of the insertion hole 44.

[0046] In addition, when metal such as filler is melted by a laser, spatters having a size of about 0.5 mm or more are likely to be generated. In the embodiment, since the communication passage 54 has a cylindrical shape with a diameter of 1.5 mm to 2 mm, the spatters generated in the welded portion 52 reach the communication passage 54 through the space portion 53. The spatters that reach the communication passage 54 head toward the insertion hole 44, but cannot enter the inside of the pinion shaft fixing pin 60 because the through hole 63 provided in the communication passage facing portion 61 of the pinion shaft fixing pin 60 inserted into the insertion hole 44 has a diameter of up to 0.5 mm. This makes it possible to suppress a part of the molten metal such as spatters from being discharged to the outside. In addition, since the through hole 63 has a diameter larger than 0.3 mm, the gas generated in the welded portion 52 is easily discharged to the outside through the through hole 63 from the end of the insertion hole 44.

[0047] As a result, when the differential case 3 and the differential ring gear 2 are fitted and welded, the gas and spatter generated from the welded portion 52 pass through the space portion 53 and the communication passage 54 toward the insertion hole 44 of the differential case 3. At this time, the gas passes through the inside of the hollow pinion shaft fixing pin 60 and is discharged to the outside through the through hole 63 of a predetermined size provided in the pinion shaft fixing pin 60 that is inserted in advance into the insertion hole 44, while spatter larger than the through hole 63 does not enter the inside of the pinion shaft fixing pin 60. With a simple configuration in which the communication passage 54 is provided in the differential case 3 and the through hole 63 of a predetermined size is provided in the pinion shaft fixing pin 60, only the gas can be discharged to the outside. Therefore, even when laser welding is performed with the pinion shaft 42 and the pinion shaft fixing pin 60 attached to the differential case 3 in advance, a vehicle differential device 1 can be provided that can discharge the gas generated when welding the differential case 3 and the differential ring gear 2.

[0048] Furthermore, since the pinion shaft fixing pin 60 has the cylindrical portion 62 that extends cylindrically, gas can pass through the inside of the cylindrical portion 62 and be easily discharged to the outside.

[0049] Furthermore, since the through holes 63 are provided around the entire circumference of the pinion shaft fixing pin 60, there is no need to position the pinion shaft fixing pin 60 in the circumferential direction, and the pinion shaft fixing pin 60 can be easily attached to the insertion hole 44.

[0050] Next, a pinion shaft fixing pin according to another embodiment will be described in detail.

[0051] In this embodiment, the pinion shaft fixing pin 60 has a cylindrical portion 62 that extends straight in a cylindrical shape, but the pinion shaft fixing pin 60 may have a cylindrical portion of another shape.

[0052] FIG. 3 is a schematic diagram showing a pinion shaft fixing pin 160 according to another embodiment. The pinion shaft fixing pin 160 has a narrowed portion 164 recessed from the outside to the inside in a communication passage facing portion 161 facing the other end of the communication passage 54 of the differential case 3. Between the cylindrical portion 162 and the narrowed portion 164, an inclined portion 165 is provided so that the diameter gradually decreases along the axial direction of the pinion shaft fixing pin 160. In addition, the narrowed portion 164 has a through hole 163 of a predetermined size that releases only gas to the outside. In the embodiment, the through hole 163 also has a diameter of 0.3 mm to 0.5 mm as a predetermined size, although it is not limited thereto.

[0053] In the embodiment, the through holes 163 are provided in the narrowed portion 164 of the pinion shaft fixing pin 160, so that the gas passes through the gap between the insertion hole 44 and the narrowed portion 164 and enters the inside of the cylindrical portion 162 from the through holes 163 provided around the entire circumference of the narrowed portion 164. This allows the gas to pass through the inside of the cylindrical portion 162 and be easily discharged to the outside.

[0054] 4 is a schematic diagram showing a pinion shaft fixing pin 260 according to another embodiment. In particular, FIG. 4(a) shows a side view of the pinion shaft fixing pin 260, while FIG. 4(b) shows a top view of the pinion shaft fixing pin 260. As shown in FIG. 4, the pinion shaft fixing pin 260 has a C-shaped open cylindrical portion 262 that extends along the axial direction of the pinion shaft fixing pin 260 and has an opening 264 in which a part of the side surface in the circumferential direction is cut out. The pinion shaft fixing pin 260 is disposed such that the opening 264 is located on the radially opposite side to the other end of the communication passage 54 of the differential case 3.

[0055] 5 is a schematic diagram showing pinion shaft fixing pin 260 and positioning tool 300 of FIG. Positioning tool 300 has a column portion 301 extending in a substantially cylindrical shape. At one end of this column portion 301, at a position offset outward from the center, a substantially cylindrical pin fitting portion 302 is provided that extends along the axial direction of column portion 301 and has a smaller diameter than column portion 301. The diameter of this pin fitting portion 302 is equal to the circumferential width of opening 264 of pinion shaft fixing pin 260.

[0056] 5, when pinion shaft fixing pin 260 is inserted into insertion hole 44 of differential case 3, opening 264 of pinion shaft fixing pin 260 is fitted into pin fitting portion 302 of positioning tool 300. As a result, pinion shaft fixing pin 260 is inserted into insertion hole 44 such that opening 264 is located on the radially opposite side to the other end of communication passage 54 of differential case 3.

[0057] In the embodiment, since pinion shaft fixing pin 260 has C-shaped opening tubular portion 262, pinion shaft fixing pin 260 can be reduced in diameter and easily assembled into insertion hole 44. Furthermore, by attaching pinion shaft fixing pin 260 to insertion hole 44 in a state in which pin fitting portion 302 of positioning tool 300 is inserted into opening 264 of pinion shaft fixing pin 250, pinion shaft fixing pin 260 can be easily positioned in the circumferential direction.

[0058] The present invention is not limited to the exemplified embodiments, and various improvements and design modifications are possible without departing from the gist of the present invention.

[0059] As described above, according to the present invention, by performing laser welding with the pinion shaft and pinion shaft fixing pin pre-attached to the differential case, it is possible to exhaust gas in the space between the differential case and the differential ring gear. Therefore, the present invention may be suitably used in the field of manufacturing technology for vehicles equipped with differential devices. [Explanation of symbols]

[0060] 1 Differential device 2 Differential ring gear 3 Differential case 21 Inner circumference side 31 Outer periphery 42 Pinion shaft 44 Insertion hole 51 Fitting part 52 Welding 54 Communication path 60 Pinion shaft fixing pin 63 Through hole

Claims

1. A differential device for a vehicle including a fitting portion where an outer peripheral side surface of a differential case and an inner peripheral side surface of a differential ring gear are fitted together, and a weld portion that is welded between the differential case and the differential ring gear outside the fitting portion, The differential case is provided with a pinion shaft extending in a direction perpendicular to the axis of the differential ring gear on the inside of the fitting portion, an insertion hole extending to intersect with the pinion shaft and communicate with the outside, and a hollow pinion shaft fixing pin extending through the insertion hole to penetrate one end of the pinion shaft in order to fix the pinion shaft. The differential case is provided with a communication passage having one end opening toward the welded portion and the other end opening into the insertion hole, The pinion shaft fixing pin is provided with a through hole of a predetermined size at an axial position opposite to the other end of the communication passage, the pinion shaft fixing pin has a communication passage facing portion that faces the other end of the communication passage, and the through hole is provided in the communication passage facing portion. A differential device for a vehicle.

2. 2. The vehicle differential device according to claim 1, wherein the pinion shaft fixing pin has a cylindrical portion that extends in a cylindrical shape.

3. 3. The differential device for a vehicle according to claim 2, wherein the through hole is provided around the entire circumference of the pinion shaft fixing pin.

4. the pinion shaft fixing pin is provided with a narrowed portion recessed from the outside toward the inside at a position facing the other end of the communication passage, 4. The differential device for a vehicle according to claim 3, wherein the through hole is provided in the narrowed portion.

5. The pinion shaft fixing pin has a C-shaped open tubular portion extending along an axial direction of the pinion shaft fixing pin and including an opening formed by cutting out a portion of a side surface in a circumferential direction, 2. The vehicle differential device according to claim 1, wherein the pinion shaft fixing pin is disposed so that the opening is located radially opposite to the other end of the communication passage of the differential case.

6. The differential device for a vehicle as described in claim 5, characterized in that the pinion shaft fixing pin is positioned so that the opening is located radially opposite the other end of the communication passage of the differential case using a positioning tool having a pin fitting portion that is inserted into the opening.

Images