JP2020153485A - Differential motion transmission device - Google Patents

Abstract

To reduce a possibility that tooth contact between a pinion gear and a side gear is deteriorated due to the deflection of a pinion shaft, in a differential motion transmission device having the short-type pinion shaft.SOLUTION: A differential motion transmission device includes: a ring-shaped member for supporting short-type pinion shafts at a center side in a radial direction, and at the outside in the radial direction; first and second side gears; a first member arranged at a first side reverse to a side of the ring-shaped member with respect to the first side gear in an axial direction, and covering the first side gear in the axial direction; and a second member arranged at a second side reverse to the side of the ring-shaped member with respect to the second side gear in the axial direction, and covering the second side gear in the axial direction. The ring-shaped member, the first member and the second member are different members, and form a differential case by being connected to one another.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a differential transmission device.

A type (short type) differential transmission device is known in which a plurality of pinion shafts do not cover the entire diameter when viewed in the axial direction of the axle, but extend radially outward from the center side in the radial direction.

Japanese Unexamined Patent Publication No. 2011-185402

By the way, in a differential transmission device in which the pinion shaft is a short type, when the pinion shaft is supported by the differential case only on the radial outer side (that is, the pinion shaft is in a cantilevered state), the pinion shaft is easily bent and the pinion gear. And the side gear tend to get worse.

Therefore, on one aspect, an object of the present invention is to reduce the possibility of deterioration of tooth contact between the pinion gear and the side gear due to bending of the pinion shaft in a differential transmission device having a short pinion shaft. To do.

One side surface has a ring-shaped shape when viewed in the axial direction of the axle, and a plurality of pinion shafts and a plurality of pinions extending radially outward from the radial center side in the radial direction centered on the axle. A ring-shaped member having a gear and supporting each of the pinion shafts on the radial center side and the radial outer side.
The first side gear that meshes with the pinion gear and
The second side gear that meshes with the pinion gear and
A first member provided on the first side opposite to the ring-shaped member with respect to the first side gear in the axial direction and covering the first side gear in the axial direction.
A second member provided on the second side opposite to the ring-shaped member with respect to the second side gear in the axial direction and covering the second side gear in the axial direction is included.
A differential transmission device is provided in which the ring-shaped member, the first member, and the second member are separate members and are coupled to each other to form a differential case.

On one side, according to the present invention, in a differential transmission device in which the pinion shaft is a short type, it is possible to reduce the possibility of deterioration of tooth contact between the pinion gear and the side gear due to the bending of the pinion shaft. Become.

It is sectional drawing which shows the differential transmission apparatus by Example 1. FIG. It is sectional drawing of the ring-shaped member along the line BB of FIG. It is explanatory drawing (the 1) of the assembling method of a differential transmission device. It is explanatory drawing (the 2) of the assembling method of a differential transmission device. It is explanatory drawing (the 3) of the assembling method of a differential transmission device. It is explanatory drawing (the 4) of the assembling method of a differential transmission device. It is explanatory drawing (the 5) of the assembling method of a differential transmission device. It is explanatory drawing (the 6) of the assembling method of a differential transmission device. It is sectional drawing which shows the differential transmission apparatus by Example 2. FIG.

Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings.

[Example 1]
FIG. 1 is a cross-sectional view showing a differential transmission device 1 according to an embodiment (Example 1). FIG. 2 is a cross-sectional view of the ring-shaped member 30. FIG. 1 corresponds to a cross section along the line AA of FIG. 2, and FIG. 2 corresponds to a cross section over the entire circumference along the line BB of FIG. Note that FIG. 1 also includes components other than the differential transmission device 1 (for example, a case 4 accommodating the differential transmission device 1 and the like, a part of other mechanisms arranged in the case 4 and the like). It is shown. In addition, in FIG. 1 and the like, for the sake of easy viewing, there are cases where a reference reference numeral is only partially attached to a plurality of parts having the same attribute.

FIG. 1 shows a centerline I along the axial direction of the axle. In the following, unless otherwise specified, the axial direction refers to the direction along the center line I, the radial direction refers to the radial direction from the center line I, and the circumferential direction is the circumferential direction around the center line I. The axis circumference refers to the center line I circumference. Further, in FIG. 1, the X1 side and the X2 side are defined in the axial direction.

The differential transmission device 1 forms a part of the vehicle drive device (the whole is not shown and the same applies hereinafter), and is connected to the output shaft of the vehicle drive device. The details of the vehicle drive device may be arbitrary, including a power source such as an electric motor or an engine, and may have a configuration capable of transmitting rotational torque to the differential transmission device 1.

The differential transmission device 1 transmits the rotational torque transmitted from the output shaft of the vehicle drive device to the axle. In FIG. 1, the intermediate shaft 80 on the X1 side that transmits rotational torque to the axle is shown, but the drive shaft on the X2 side is not shown.

The differential transmission device 1 is rotatably supported around the axis with respect to the case 4. The differential transmission device 1 includes a first differential case 10 (an example of a first member), a second differential case 20 (an example of a second member), a ring-shaped member 30, a first side gear 41, and a second side gear 42. including.

The first differential case 10 is provided on the X1 side (an example of the first side) opposite to the ring-shaped member 30 with respect to the first side gear 41 in the axial direction. The first differential case 10 extends in a region overlapping the first side gear 41 when viewed in the axial direction. That is, the first differential case 10 covers the first side gear 41 in the axial direction. The first differential case 10 does not need to cover the entire first side gear 41 in the axial direction, and may be covered in such a manner that the load bearing function described later is ensured. The first differential case 10 has a function of receiving a load from the first side gear 41 to the X1 side in the axial direction (load receiving function). In FIG. 1, the first differential case 10 rotatably supports the first side gear 41 via a washer 51. In this case, the first differential case 10 bears a load from the first side gear 41 to the X1 side in the axial direction via the washer 51.

The first differential case 10 has a form in which the intermediate shaft 80 on the X1 side passes inside in the radial direction, and is connected to the output shaft of the vehicle drive device. When the output shaft of the vehicle drive device rotates, the first differential case 10 rotates around the shaft.

The second differential case 20 is provided on the X2 side (an example of the second side) opposite to the ring-shaped member 30 with respect to the second side gear 42 in the axial direction. The second differential case 20 extends in a region overlapping the second side gear 42 when viewed in the axial direction. That is, the second differential case 20 covers the second side gear 42 in the axial direction. The second differential case 20 does not need to cover the entire second side gear 42 in the axial direction, and may be covered in such a manner that the load bearing function described later is ensured. The second differential case 20 has a function of receiving a load from the second side gear 42 to the X2 side in the axial direction (load receiving function). In FIG. 1, the second differential case 20 rotatably supports the second side gear 42 via a washer 52. In this case, the second differential case 20 bears the load from the second side gear 42 to the X2 side in the axial direction via the washer 52.

The second differential case 20 has a form in which a drive shaft (not shown) on the X2 side passes inside in the radial direction. The radial outer side of the second differential case 20 is rotatably supported by the case 4 via a bearing 82.

The ring-shaped member 30 has a ring-shaped shape when viewed in the axial direction, and inward in the radial direction, the end 81 on the X2 side of the intermediate shaft 80 on the X1 side, the shaft portion 410 of the first side gear 41, and the X2 side. The end of the drive shaft (not shown) on the X1 side and the shaft portion 420 of the second side gear 42 are arranged.

The ring-shaped member 30 is a member different from the first differential case 10 and the second differential case 20 described above, but is combined with the first differential case 10 and the second differential case 20 to form a differential case. That is, in this embodiment, the first differential case 10, the second differential case 20, and the ring-shaped member 30 are separate members, but are finally combined to form an integral differential case.

The ring-shaped member 30 is fitted to each of the first differential case 10 and the second differential case 20 in a manner of abutting in the axial direction and the radial direction. In the example shown in FIG. 1, in the ring-shaped member 30, the outer peripheral portion 302 described later abuts on each of the first differential case 10 and the second differential case 20 in the axial direction and the radial direction. At this time, the first differential case 10 and the second differential case 20 come into contact with the flange surface 3023 of the outer peripheral portion 302 described later in the ring-shaped member 30 from the outside in the radial direction.

The method of connecting the ring-shaped member 30 and the first differential case 10 and the method of connecting the ring-shaped member 30 and the second differential case 20 are arbitrary, but in this embodiment, they are realized by welding as an example.

Specifically, the ring-shaped member 30 and the first differential case 10 have a welded portion 61 (an example of the first welded portion) extending in the circumferential direction. That is, the ring-shaped member 30 and the first differential case 10 abut on the outer peripheral portion in the axial direction, and the abutting portion is welded. The welded portion 61 is provided over the entire circumference in the circumferential direction. However, in the modified example, the welded portion 61 may be provided only in a part in the circumferential direction.

Similarly, the ring-shaped member 30 and the second differential case 20 have a welded portion 62 (an example of the second welded portion) extending in the circumferential direction. That is, the ring-shaped member 30 and the second differential case 20 abut on the outer peripheral portion in the axial direction, and the abutting portion is welded. The welded portion 62 is provided over the entire circumference in the circumferential direction. However, in the modified example, the welded portion 62 may be provided only in a part in the circumferential direction.

Here, in this embodiment, the welded portion 61 is formed at a portion that is visible in the radial direction. Therefore, the welding related to the welded portion 61 can be easily performed from the outside in the radial direction with the ring-shaped member 30 and the first differential case 10 aligned in the axial direction. Similarly, the welded portion 62 is formed at a portion that is visible in the radial direction. Therefore, the welding related to the welded portion 62 can be easily performed from the outside in the radial direction with the ring-shaped member 30 and the second differential case 20 aligned in the axial direction.

As shown in FIG. 2, the ring-shaped member 30 has a plurality of pinion shafts 310 and a plurality of pinion gears 320. In the example shown in FIG. 2, the pinion shaft 310 and the pinion gear 320 are arranged in four sets at equal intervals (every 90 degrees) in the circumferential direction. The number of pairs of the pinion shaft 310 and the pinion gear 320 is arbitrary, and for example, three pairs may be arranged at equal intervals (every 120 degrees) in the circumferential direction.

Each of the plurality of pinion shafts 310 is a short type and extends from the radial center side to the radial outer side. That is, each of the plurality of pinion shafts 310 has an end portion 311 on the radial center side and an end portion 312 on the radial outer side, and has a substantially equal cross section (circular cross-sectional shape) from the end portion 311 to the end portion 312. Extends in the radial direction. As described above, since the plurality of pinion shafts 310 are arranged at equal intervals in the circumferential direction, they extend radially outward from the radial center side as a whole.

Each of the plurality of pinion shafts 310 is formed with a pin hole 3102 that penetrates in the axial direction at the end portion 312 on the outer side in the radial direction.

Each of the plurality of pinion gears 320 is rotatably provided around the corresponding pinion shaft 310. Each of the plurality of pinion gears 320 meshes with the first side gear 41 and the second side gear 42 in the radial direction with respect to the pinion shaft 310.

In this embodiment, each of the plurality of pinion gears 320 has a tooth bottom surface 321 and a tooth tip surface 322 parallel to the pinion shaft 310, as shown in FIG. As a result, the length in the axial direction can be shortened as compared with the case where the surface 322 of the tooth tip is inclined with respect to the pinion shaft 310 like the surface 321 of the tooth bottom.

As shown in FIG. 2, the ring-shaped member 30 supports each of the plurality of pinion shafts 310 on the radial center side and the radial outer side. That is, the ring-shaped member 30 supports each of the plurality of pinion shafts 310 with the end portion 311 on the radial center side and the end portion 312 on the radial outer side.

Specifically, the ring-shaped member 30 includes an outer peripheral portion 302, an inner peripheral portion 303, and a bridge portion 304. The outer peripheral portion 302, the inner peripheral portion 303, and the bridge portion 304 are integrated. The outer peripheral portion 302, the inner peripheral portion 303, and the bridge portion 304 are formed integrally, for example, but may be formed separately and connected.

The outer peripheral portion 302 forms the outer peripheral portion of the ring-shaped member 30, and extends over the entire circumferential direction. A radial hole 3021 is formed in the outer peripheral portion 302 to receive the radial outer end portion 312 of the pinion shaft 310. The hole 3021 is in the form of a through hole in the radial direction, for example, as shown in FIG. The inner diameter of the hole 3021 is slightly larger than the maximum value (constant value in the illustrated example) of the outer diameter of the pinion shaft 310, and is substantially the same as the outer diameter of the end portion 312 on the outer side in the radial direction.

A pin hole 3022 (see FIG. 1) penetrating in the axial direction is formed in the outer peripheral portion 302. The pin 90 is inserted into the pin hole 3022 in a state of being aligned with the pin hole 3102 of the pinion shaft 310. That is, the pin 90 is inserted into the pin hole 3022 and the pin hole 3102, and the radial displacement of the pinion shaft 310 with respect to the ring-shaped member 30 (the axial displacement of the pinion shaft 310) is constrained.

As shown in FIG. 1, the outer peripheral surface of the outer peripheral portion 302 is flush with adjacent portions (same diameter) on the outer peripheral surfaces of the first differential case 10 and the second differential case 20. As a result, welding of the welded portion 61 and the welded portion 62 becomes easy.

The inner peripheral portion 303 forms an inner peripheral portion of the ring-shaped member 30, and extends over the entire circumferential direction. A radial hole 3031 is formed in the inner peripheral portion 303 to receive the end portion 311 on the radial center side of the pinion shaft 310. The hole 3031 is in the form of a through hole, for example, as shown in FIG. 2, but the inside in the radial direction may be closed. The inner diameter of the hole 3031 is substantially the same as the outer diameter of the radial inner end 311 of the pinion shaft 310. The inner peripheral portion 303 may be coupled to the pinion shaft 310 in such a manner that the end portion 311 of the pinion shaft 310 is press-fitted into the hole 3031.

The bridge portion 304 extends in the radial direction in a manner in which the outer peripheral portion 302 and the inner peripheral portion 303 are connected in the radial direction. The bridge portions 304 are arranged between the plurality of pinion shafts 310 in the circumferential direction, and are arranged at equal intervals (every 90 degrees) in the circumferential direction.

According to such a ring-shaped member 30, in each of the plurality of pinion shafts 310, the end portion 311 on the radial center side is firmly supported by the inner peripheral portion 303. That is, since the end portion 311 on the radial center side abuts on the inner peripheral portion 303 over the entire circumferential direction of the corresponding pinion shaft 310 (because it abuts on the inner peripheral portion 303 in the radial direction), it abuts on the inner peripheral portion 303. On the other hand, it is substantially constrained except in the axial direction of the pinion shaft 310. Similarly, for each of the plurality of pinion shafts 310, the radial outer end 312 is firmly supported by the outer peripheral 302. That is, since the radial outer end portion 312 abuts on the outer peripheral portion 302 over the entire circumferential direction of the corresponding pinion shaft 310, substantially the inner peripheral portion 303 except in the axial direction of the pinion shaft 310. Be restrained. The displacement of the pinion shaft 310 in the axial direction (axial direction of the pinion shaft 310) with respect to the ring-shaped member 30 may be constrained by the pin 90 as described above.

The first side gear 41 is provided between the ring-shaped member 30 and the first differential case 10 in the axial direction. The first side gear 41 meshes with each of the plurality of pinion gears 320. The first side gear 41 is a crown gear, and the surface 412 of the tooth tip and the surface 411 of the tooth bottom are parallel to the pinion shaft 310. As a result, the length in the axial direction can be shortened as compared with the case where the surface 411 of the tooth bottom is inclined with respect to the pinion shaft 310 like the surface 412 of the tooth tip.

The first side gear 41 is connected to the intermediate shaft 80 on the X1 side in the radial direction in a manner of integrally rotating with the intermediate shaft 80 on the X1 side. For example, the first side gear 41 is spline-fitted with the intermediate shaft 80 on the X1 side. The first side gear 41 has a shaft portion 410 extending radially inward from the ring-shaped member 30, and an intermediate shaft 80 is inserted inside the shaft portion 410 in a radial direction so that the intermediate shaft 80 cannot rotate relative to each other. The shaft portion 410 extends inward in the radial direction of the ring-shaped member 30 in such a manner that the end portion on the X2 side overlaps the ring-shaped member 30 in the axial direction.

The second side gear 42 is provided between the ring-shaped member 30 and the second differential case 20 in the axial direction. The second side gear 42 meshes with each of the plurality of pinion gears 320. The second side gear 42 is a crown gear, and the surface 422 of the tooth tip and the surface 421 of the tooth bottom are parallel to the pinion shaft 310. As a result, the length in the axial direction can be shortened as compared with the case where the surface 421 of the tooth bottom is inclined with respect to the pinion shaft 310 like the surface 422 of the tooth tip.

The second side gear 42 is connected to the drive shaft on the X2 side (not shown) on the inner side in the radial direction in a manner of integrally rotating with the drive shaft on the X2 side (not shown). For example, the second side gear 42 is spline-fitted with a drive shaft (not shown) on the X2 side. The second side gear 42 has a shaft portion 420 extending radially inward from the ring-shaped member 30, and a drive shaft (not shown) is inserted inside the shaft portion 420 in a relative non-rotatable manner. To. The shaft portion 420 extends inward in the radial direction of the ring-shaped member 30 in such a manner that the end portion on the X1 side overlaps the ring-shaped member 30 in the axial direction.

The operation itself of the differential transmission device 1 of this embodiment is the same as that of a normal differential transmission device. Generally speaking, when the resistance applied to the first side gear 41 and the second side gear 42 is the same, the pinion gear 320 revolves around the shaft (axle) without rotating around the pinion shaft 310, and the first side gear 41 and the second side gear 42 2 The side gear 42 is rotated at the same rotation speed as the revolution. On the other hand, if the resistances applied to the first side gear 41 and the second side gear 42 are different, the pinion gear 320 revolves while rotating, causing the first side gear 41 and the second side gear 42 to rotate at different rotation speeds.

According to this embodiment, although the pinion shaft 310 is a short type as described above, both ends of each of the plurality of pinion shafts 310 are supported by the ring-shaped member 30. Then, as described above, the ring-shaped member 30 forms a differential case. Therefore, according to this embodiment, even though the pinion shaft 310 is a short type, both ends of each of the plurality of pinion shafts 310 can be supported by the differential case. As a result, the plurality of pinion shafts 310 are less likely to bend, and the tooth contact between the pinion gear 320 and the first side gear 41 and the second side gear 42 can be maintained satisfactorily. That is, according to the present embodiment, in the differential transmission device 1 in which the pinion shaft 310 is a short type, the tooth contact between the pinion gear 320 and the first side gear 41 and the second side gear 42 due to the bending of the pinion shaft 310 deteriorates. The possibility can be reduced.

More specifically, in the first comparative example (not shown, for example, a configuration as in Patent Document 1) in which the axial center side of the short type pinion shaft is not supported by the differential case, the pinion shaft is cantilevered and thus bends. It will be easier. Therefore, in the first comparative example, if the pinion shaft is bent due to the force generated between the side gear and the pinion gear, there is a disadvantage that the tooth contact between the pinion gear and the side gear is deteriorated. On the other hand, according to this embodiment, as described above, the inconvenience of the first comparative example can be reduced.

By the way, when the axial center side of the short type pinion shaft is supported by the differential case, the possibility of deterioration of tooth contact between the pinion gear and the side gear due to the bending of the pinion shaft can be reduced, but the assembling property of the side gear is a problem. Can be.

Specifically, in the second comparative example (not shown) in which the ring-shaped member 30, the first differential case 10, and the second differential case 20 form an integrated differential case from the beginning, the first side gear 41 and the second side gear 42 Assembly is virtually impossible. That is, unlike the present embodiment, in the case of the second comparative example in which the ring-shaped member 30, the first differential case 10, and the second differential case 20 are not separate members, the first side gear 41 and the second side gear 42 are assembled to the differential case. I can't.

In this regard, in this embodiment, as described above, the ring-shaped member 30, the first differential case 10, and the second differential case 20 are separate members. It is easy to assemble the first side gear 41 between the ring-shaped member 30 and the first differential case 10, and it is easy to assemble the second side gear 42 between the ring-shaped member 30 and the second differential case 20. is there.

As described above, according to the present embodiment, it is possible to secure good assembling property of the first side gear 41 and the second side gear 42 while realizing the double-sided structure of the short type pinion shaft 310.

Next, the method of assembling the differential transmission device 1 according to the present embodiment will be outlined with reference to FIGS. 3A to 3F.

3A to 3F are explanatory views of an assembling method of the differential transmission device 1 according to the present embodiment, and each state during assembling is shown in a cross-sectional view.

In the first step, the first differential case 10 is prepared. When assembled together with other structures of the vehicle drive device, the first differential case 10 may be assembled to the output shaft of the vehicle drive device as shown in FIG. 3A.

In the second step after the first step, as shown in FIG. 3B, the first side gear 41 is assembled to the first differential case 10. The first side gear 41 may be assembled together with the washer 51 to the first differential case 10. The ring-shaped member 30 is not assembled when the first side gear 41 is assembled, and therefore, the assembling property of the first side gear 41 is good.

In the third step after the second step, the ring-shaped member 30 is assembled as shown in FIG. 3C. That is, the ring-shaped member 30 is fitted to the first differential case 10 in a manner in which the first side gear 41 is sandwiched between the first differential case 10 and the first differential case 10 in the axial direction. The ring-shaped member 30 may be assembled with the pinion shaft 310 and the pinion gear 320 assembled.

In the fourth step after the third step, the second side gear 42 is assembled as shown in FIG. 3D. The second differential case 20 is not assembled when the second side gear 42 is assembled. Therefore, the assembling property of the second side gear 42 is good.

In the fifth step after the fourth step, the second differential case 20 is assembled as shown in FIG. 3E. The second differential case 20 is fitted to the ring-shaped member 30 in a manner in which the second side gear 42 is sandwiched between the ring-shaped member 30 and the ring-shaped member 30 in the axial direction. The second differential case 20 may be assembled together with the washer 52.

In the sixth step after the fifth step, as shown in FIG. 3F, the first differential case 10 and the ring-shaped member 30 are welded to form a welded portion 61, and the second differential case 20 and the ring-shaped member 30 are formed. Is welded to form a welded portion 62. In the modified example, the welding between the first differential case 10 and the ring-shaped member 30 may be executed after the ring-shaped member 30 is assembled (after the third step).

In this way, the differential transmission device 1 of this embodiment is assembled. When assembled together with other structures of the vehicle drive device, the differential transmission device 1 is then assembled in the axial direction from the X1 side to the X2 side with respect to the case 4.

[Example 2]
FIG. 4 is a cross-sectional view showing a differential transmission device 1A according to another embodiment (Example 2).

In the differential transmission device 1A according to the present embodiment, the first differential case 10, the second differential case 20, and the ring-shaped member 30 are the first differential case 10A and the second with respect to the differential transmission device 1 according to the above-described first embodiment. The difference is that they are replaced by the differential case 20A and the ring-shaped member 30A, respectively. Further, the differential transmission device 1A according to the present embodiment is different from the differential transmission device 1 according to the above-described first embodiment in that the welded portions 61 and 62 are replaced by the welded portions 61A and 62A, respectively.

The first differential case 10A, the second differential case 20A, and the ring-shaped member 30A have the welded portions 61, 62 and the welded portions 61A, 62A with respect to the above-mentioned first differential case 10, the second differential case 20, and the ring-shaped member 30. It only has a difference in structure (shape) related to the difference between the two, and the functions and the like may be the same.

Specifically, in the above-described first embodiment, the first differential case 10 and the ring-shaped member 30 have an outer peripheral surface having the same diameter at the welded portion 61, whereas in the present embodiment, the first differential case 10A And the ring-shaped member 30A have a radial offset at the welded portion 61A. Specifically, the first differential case 10A has a flange portion 101A that protrudes toward the X2 side in the axial direction on the outer peripheral portion, and a ring-shaped member 30A is fitted inside the flange portion 101A in the radial direction. Further, the outer peripheral portion 302A of the ring-shaped member 30A has a portion 3024A offset inward in the radial direction due to a step on the outer peripheral surface, and the first differential case 10A and the ring-shaped member 30A are welded using the step. .. That is, the welded portion 61A is formed at a portion visible in the axial direction at the radial contact portion between the flange portion 101A of the first differential case 10A and the outer peripheral portion 302A of the ring-shaped member 30A. Therefore, in this case, the welding related to the welded portion 61A can be easily performed from the X2 side in the axial direction with the ring-shaped member 30A fitted in the first differential case 10A.

Similarly, in the above-described first embodiment, the second differential case 20 and the ring-shaped member 30 have an outer peripheral surface having the same diameter at the welded portion 62, whereas in the present embodiment, the second differential case 20A And the ring-shaped member 30A have a radial offset at the welded portion 62A. Specifically, the ring-shaped member 30A has a flange portion 3027A that projects axially toward the X2 side in the outer peripheral portion 302A, and the second differential case 20A is fitted inside the flange portion 3027A in the radial direction. Further, the end face on the X2 side in the axial direction of the flange portion 3027A is flush with the end face on the X2 side in the axial direction of the outer peripheral portion of the second differential case 20A, and the portion where the end faces are adjacent to each other in the radial direction is used. , The second differential case 20A and the ring-shaped member 30A are welded together. Also in this case, the welded portion 62A is formed at a position visible in the axial direction. Therefore, in this case, the welding related to the welded portion 62A can be easily performed from the X2 side in the axial direction with the second differential case 20A fitted to the ring-shaped member 30A.

As described above, also in this embodiment, as in the case of the first embodiment described above, it is possible to secure a good assembling property of the first side gear 41 and the second side gear 42 while realizing the double-sided structure of the short type pinion shaft 310.

Although each embodiment has been described in detail above, the present invention is not limited to a specific embodiment, and various modifications and changes can be made within the scope of the claims. It is also possible to combine all or a plurality of the components of the above-described embodiment.

<Additional notes>
The following will be further disclosed with respect to the above examples. Of the effects described below, the effect relating to each additional form with respect to one form is an additional effect resulting from each of the additional forms.

(1) One form is a ring-shaped form when viewed in the axial direction (I) of the axle, and a plurality of forms extending radially outward from the radial center side in the radial direction centered on the axle. A ring-shaped member (30, 30A) having a pinion shaft (310) and a plurality of pinion gears (320) and supporting each of the pinion shafts on the radial center side and the radial outer side.
The first side gear (41) that meshes with the pinion gear and
The second side gear (42) that meshes with the pinion gear and
With the first member (10, 10A) provided on the first side (X1 side) opposite to the ring-shaped member with respect to the first side gear in the axial direction and covering the first side gear in the axial direction. ,
With the second member (20, 20A) provided on the second side (X2 side) opposite to the ring-shaped member with respect to the second side gear in the axial direction and covering the second side gear in the axial direction. Including
The ring-shaped member, the first member, and the second member are separate members, and are differential transmission devices (1, 1A) that form a differential case when they are connected to each other.

According to this embodiment, since the ring-shaped member supports each of the pinion shafts on the radial center side and the radial outer side, there is a possibility that the tooth contact between the pinion gear and the side gear may be deteriorated due to the bending of the pinion shaft. Can be reduced. Further, since the ring-shaped member, the first member, and the second member are separate members, even if the ring-shaped member supports each of the pinion shafts on the radial center side and the radial outer side, the side gear It can be assembled.

(2) Further, in the present embodiment, preferably, the ring-shaped member and the first member have first welded portions (61, 61A) extending in the circumferential direction, and the ring-shaped member and the first member. The two members have a second weld (62, 62A) extending in the circumferential direction.

In this case, the ring-shaped member, the first member, and the second member can be connected via the first welded portion and the second welded portion.

(3) Further, in the present embodiment, preferably, at least one of the first welded portion and the second welded portion is formed at a portion visible in the radial direction.

In this case, at least one of the first welded portion and the second welded portion can be formed from the radial outside.

(4) Further, in the present embodiment, preferably, at least one of the first welded portion and the second welded portion is formed at a portion visible in the axial direction.

In this case, at least one of the first welded portion and the second welded portion can be formed from the axial direction.

(5) Further, in the present embodiment, preferably, the first side gear and the second side gear are crown gears.

In this case, the axial length of the mounting space of the structural portion including the pinion gear and the first and second side gears can be shortened.

1, 1A Differential transmission device 4 Case 10, 10A 1st differential case 20, 20A 2nd differential case 30, 30A Ring-shaped member 41 1st side gear 42 2nd side gear 51 Washer 52 Washer 61, 61A Welded part 62, 62A Welded part 80 Intermediate shaft 81 End 82 Bearing 90 Pin 101A Flange 302, 302A Outer circumference 303 Inner circumference 304 Bridge 310 Pinion shaft 311 End 312 End 320 Pinion gear 322 Toe surface 410 Shaft 420 Shaft 3021 Hole 3022 Pin hole 3023 Flange surface 3024A Part 3027A Flange part 3031 hole 3102 Pin hole

Claims (5)

It has a ring-shaped shape when viewed in the axial direction of the axle, and has a plurality of pinion shafts and a plurality of pinion gears extending radially outward from the radial center side in the radial direction centered on the axle. , A ring-shaped member that supports each of the pinion shafts on the radial center side and the radial outer side,
The first side gear that meshes with the pinion gear and
The second side gear that meshes with the pinion gear and
A first member provided on the first side opposite to the ring-shaped member with respect to the first side gear in the axial direction and covering the first side gear in the axial direction.
A second member provided on the second side opposite to the ring-shaped member with respect to the second side gear in the axial direction and covering the second side gear in the axial direction is included.
A differential transmission device in which the ring-shaped member, the first member, and the second member are separate members and are coupled to each other to form a differential case. The ring-shaped member and the first member have a first welded portion extending in the circumferential direction, and the ring-shaped member and the second member have a second welded portion extending in the circumferential direction. Item 1. The differential transmission device according to item 1. The differential transmission device according to claim 1 or 2, wherein at least one of the first welded portion and the second welded portion is formed at a portion visible in the radial direction. The differential transmission device according to claim 2 or 3, wherein at least one of the first welded portion and the second welded portion is formed at a portion visible in the axial direction. The differential transmission device according to any one of claims 1 to 4, wherein the first side gear and the second side gear are crown gears.