JP7396187B2 - Vehicle differential gear - Google Patents

Description

The present invention relates to a vehicle differential device that distributes the driving force of a vehicle's drive source to a pair of output shafts while allowing differential movement.

Conventionally, in vehicles, differential devices that distribute the driving force of a drive source such as an engine to a pair of output shafts while allowing differential rotation have a differential limiting function that suppresses differential rotation between the output shafts. There is. A vehicle equipped with such a differential device can transmit driving force to the left wheel even when the right wheel slips, for example, so that driving stability is improved. The present applicant has proposed the one in Patent Document 1 as a vehicle differential device having a configuration that further increases a differential limiting force that suppresses differential rotation between output shafts.

The vehicle differential device described in Patent Document 1 includes a first connecting member that is relatively unrotatably connected to one output shaft of a pair of output shafts, and a first connecting member that is relatively unrotatably connected to the other output shaft. two connecting members, a first side gear coupled with the first coupling member by a helical spline, a second side gear coupled with the second coupling member by a helical spline, and a first pinion gear and a second side gear meshed with the first side gear. It includes a plurality of pinion gear sets formed by meshing with second pinion gears. When the vehicle accelerates forward, friction is generated when the first connecting member and the first side gear, and the second connecting member and the second side gear are pressed against the washer by the axial thrust force generated in the helical spline joint. The force increases the differential limiting force.

Patent No. 6565524

In the vehicle differential device configured as described above, depending on the usage situation, the differential limiting force may fluctuate from the expected value, or the differential limiting force may change when the vehicle changes between acceleration and deceleration states. There were cases where hysteresis of the limiting force occurred. The inventors of the present invention have conducted extensive research into the causes and countermeasures for this problem, and have come up with the present invention. That is, an object of the present invention is to provide a vehicle differential device that can stably generate a high differential limiting force.

In order to achieve the above object, the present invention provides a vehicle differential device that distributes the driving force of a vehicle to a pair of output shafts while allowing a differential, wherein one of the output shafts of the pair of output shafts is a first connecting member that is relatively unrotatably connected to the other output shaft of the pair of output shafts, a second connecting member that is relatively unrotatably connected to the other output shaft of the pair of output shafts, and a first connecting member and a first connecting portion. a first side gear that is helically spline-coupled; a second side gear that is helically spline-coupled to the second connecting member at a second coupling portion; a first pinion gear that meshes with the first side gear; and a second pinion gear that meshes with the second side gear. a plurality of pinion gear sets formed by meshing with each other, and a differential case holding the plurality of pinion gear sets, the first connecting member and the first side gear sandwiching the first coupling part in the axial direction at two locations. Provided is a differential gear for a vehicle, in which the second connecting member and the second side gear are fitted with a pilot at two locations axially sandwiching the second coupling portion.

According to the vehicle differential device according to the present invention, it is possible to stably generate a high differential limiting force.

1 is a cross-sectional view showing a configuration example of a vehicle differential device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a vehicle differential device. FIG. 2 is an explanatory diagram showing the main components of the vehicle differential device. 2A and 2B are cross-sectional views showing the operating state of the vehicle differential device when the vehicle is running forward, with (a) showing the operating state during acceleration, and (b) showing the operating state during deceleration, respectively. (a) is a sectional view showing a vehicle differential device according to a comparative example. (b) to (d) are explanatory diagrams showing the meshing portion between the helical spline teeth of the first side gear and the helical spline teeth of the first connecting member, and (b) is a cross section taken along the line AA in (a). 2, (c) is a cross-sectional view taken along line BB in (a), and (d) is a cross-sectional view taken along line CC in (a).

[Embodiment]
Embodiments of the present invention will be described with reference to FIGS. 1 to 4. The embodiments described below are shown as preferred specific examples for carrying out the present invention, and some portions specifically illustrate various technical matters that are technically preferable. However, the technical scope of the present invention is not limited to this specific embodiment.

FIG. 1 is a sectional view showing a configuration example of a vehicle differential device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the vehicle differential.

This vehicle differential device 1 is used to distribute the driving force of a driving source such as a vehicle engine to a pair of output shafts 71 and 72 while allowing differential movement. In FIG. 1, the pair of output shafts 71 and 72 are shown by virtual lines (two-dot chain lines). This vehicle differential device 1 is used as a differential device that distributes the driving force of a drive source to left and right drive wheels, and distributes the input driving force to left and right drive shafts as a pair of output shafts 71 and 72. . Hereinafter, the vehicle differential device 1 will be simply referred to as the differential device 1.

The differential device 1 includes a differential case 2 into which driving force is input, a plurality of pinion gear sets 3 formed by meshing a first pinion gear 31 and a second pinion gear 32, a first side gear 41 meshing with the first pinion gear 31, and a first side gear 41 meshing with the first pinion gear 31. A second side gear 42 meshing with the 2-pinion gear 32, a first connecting member 51 connected to the first side gear 41 by a helical spline, a second connecting member 52 connected to the second side gear 42 by a helical spline, and the first side gear 41. It includes a center washer 60 disposed between the second side gear 42 and a first side washer 61 and a second side washer 62 held by the differential case 2.

A ring gear 11 shown by a virtual line (two-dot chain line) in FIG. 1 is fixed to the differential case 2 by a plurality of bolts 12. The differential case 2 rotates about the rotation axis O by the driving force of the drive source input from the ring gear 11. The first side gear 41, the second side gear 42, the first connecting member 51, and the second connecting member 52 are housed in the differential case 2, and are rotatable relative to the differential case 2 about the rotation axis O. Hereinafter, the direction parallel to the rotation axis O will be referred to as the axial direction.

The differential case 2 includes a bottomed cylindrical differential case body 21 and a differential case lid 22 arranged to close an opening of the differential case body 21. The differential case body 21 and the differential case lid 22 are connected by a plurality of bolts 23. combined. The differential case main body 21 includes a cylindrical tube portion 211, an annular first side wall portion 212 formed to extend radially inward from one axial end of the tube portion 211, and a first side wall. A cylindrical first extending portion 213 extends axially outward from the center of the portion 211, and a cylindrical first extending portion 213 extends radially outward from the other end of the first cylindrical portion 211 in the axial direction. The first flange portion 214 is integrally formed with the first flange portion 214. The first side wall portion 212 is formed with an oil hole 212a through which lubricating oil flows.

The differential case lid body 22 includes a disk-shaped second side wall 221, a cylindrical second extending portion 222 extending axially outward from the center of the second side wall 221, and a second side wall. It integrally has a second flange portion 223 formed to extend outward in the radial direction from the portion 221 . The second side wall portion 221 is formed with an oil hole 221a through which lubricating oil flows.

A bolt 12 for fixing the ring gear 11 is inserted through a first flange portion 214 of the differential case body 21 and a second flange portion 223 of the differential case lid body 22. Bearings (not shown) are arranged around the outer peripheries of the first extending portion 213 and the second extending portion 222, and the differential case 2 is rotatably supported by these bearings with respect to the differential carrier.

The first side washer 61 is held by the first side wall part 212, and the second side washer 62 is held by the second side wall part 221. The center washer 60 is arranged between the first side gear 41 and the first connecting member 51 and the second side gear 42 and the second connecting member 52. Relative rotation of the center washer 60, the first side washer 61, and the second side washer 62 with respect to the differential case 2 is restricted.

The differential case 2 accommodates four pinion gear sets 3. Each pinion gear set 3 is formed by meshing one first pinion gear 31 and two second pinion gears 32. The first pinion gear 31 is provided between a large diameter gear section 311 and a small diameter gear section 312 having different pitch circle diameters, and between the large diameter gear section 311 and the small diameter gear section 312, and is arranged from the small diameter gear section 312 side to the large diameter gear section. It has an inclined gear part 313 whose pitch circle diameter gradually increases toward the 311 side. The two second pinion gears 32 have shorter axial lengths than the first pinion gear 31 and mesh with the small diameter gear portion 312 of the first pinion gear 31, respectively.

Four bores 20 are formed in the differential case body 21 to hold four pinion gear sets 3, respectively. The inner surface of the bore 20 has a sliding surface 20a on which the large-diameter gear portion 311 of the first pinion gear 31 slides, a sliding surface 20b on which the small-diameter gear portion 312 of the first pinion gear 31 slides, and a sliding surface 20b on which the second pinion gear 32 slides. It includes a sliding surface 20c that moves. When the vehicle travels straight, the first pinion gear 31 and the second pinion gear 32 do not rotate within the bore 20 but rotate (revolution) together with the differential case 2. Further, when the pair of output shafts 71 and 72 differentially rotate when the vehicle turns, etc., the first pinion gear 31 and the second pinion gear 32 rotate together with the differential case 2 while rotating within the bore 20.

The first side gear 41 meshes with the large diameter gear portion 311 of the first pinion gear 31. The second side gear 42 meshes with the second pinion gear 32. A plurality of oblique teeth 411 and 421 whose tooth traces are inclined with respect to the axial direction are formed on the outer periphery of the first side gear 41 and the second side gear 42, respectively. The twisting direction of the plurality of helical teeth 411 in the first side gear 41 is the direction in which the first side gear 41 is pressed toward the center washer 60 when the vehicle is accelerated in the forward direction. The twisting direction of the plurality of helical teeth 421 in the second side gear 42 is the direction in which the second side gear 42 is pressed toward the center washer 60 when the vehicle is accelerated in the forward direction.

The first connecting member 51 is connected to one output shaft 71 of the pair of output shafts 71 and 72 in a relatively non-rotatable manner. A straight spline fitting portion 511 for connection with the output shaft 71 is formed on the inner peripheral surface of the first connection member 51 . The second connecting member 52 is connected to the other output shaft 72 of the pair of output shafts 71 and 72 in a relatively non-rotatable manner. A straight spline fitting portion 521 for connection to the output shaft 72 is formed on the inner peripheral surface of the second connection member 52 .

The first side gear 41 is helically spline coupled to the first connecting member 51 at the first coupling portion _J1 . The second side gear 42 is helically spline coupled to the second connecting member 52 at the second coupling portion _J2 . A plurality of helical spline teeth 412 with tooth traces inclined with respect to the axial direction are formed on the inner circumference of the first side gear 41, and a plurality of helical spline teeth 412 with tooth traces inclined with respect to the axial direction are formed on the inner circumference of the second side gear 42. A plurality of helical spline teeth 422 are formed. A plurality of helical spline teeth 512 with tooth traces inclined with respect to the axial direction are formed on the outer periphery of the first connecting member 51, and a plurality of helical spline teeth 512 with tooth traces inclined with respect to the axial direction are formed on the outer periphery of the second connecting member 52. A plurality of helical spline teeth 522 are formed.

In the first joint _J1 , the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51 mesh with each other, and this meshing causes a driving force to be applied from the first side gear 41 to the first connecting member 51. is transmitted. The torsional direction of these helical spline teeth 412, 512 is the direction in which the first side gear 41 is pressed against the center washer 60 and the first connecting member 51 is pressed against the first side washer 61 when the vehicle is accelerated in the forward direction. It is.

In the second joint _J2 , the helical spline teeth 422 of the second side gear 42 and the helical spline teeth 522 of the second connecting member 52 mesh with each other, and this meshing causes the driving force to be applied from the second side gear 42 to the second connecting member 52. is transmitted. The torsional direction of these helical spline teeth 422, 522 is the direction in which the second side gear 42 is pressed against the center washer 60 and the second connecting member 52 is pressed against the second side washer 62 when the vehicle is accelerated in the forward direction. It is.

By the way, when the vehicle is running, if the first connecting member 51 is tilted with respect to the first side gear 41 due to a radial force acting on the first connecting member 51 from one output shaft 71, for example, the first connecting member J ₁ There is a possibility that the meshing between the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51 becomes inappropriate. Similarly, when the second coupling member 52 is tilted relative to the second side gear 42 due to a radial force acting on the second coupling member 52 from the other output shaft 72, for example, the second side gear 42 at the second coupling portion _J2 There is a risk that the meshing between the helical spline teeth 422 of the helical spline teeth 522 of the second connecting member 52 and the helical spline teeth 522 of the second connecting member 52 may become inappropriate.

In the present embodiment, the first connecting member 51 and the first side gear 41 are spigot-fitted at two locations sandwiching the first joint _J1 in the axial direction, so that the first connecting member 51 and the first side gear 41 This prevents it from leaning against the other direction. Furthermore, since the second connecting member 52 and the second side gear 42 are fitted with pilots at two locations sandwiching the second joint _J2 in the axial direction, the second connecting member 52 is prevented from tilting with respect to the second side gear 42. is suppressed. The configuration for this purpose will be described in detail below with reference to FIGS. 3 and 4. Note that spigot fitting here means that at the fitting portion of the inner member and outer member that fit into each other, the outer diameter of the inner member and the inner diameter of the outer member are approximately equal, and the inner member and outer member are axially aligned. means a fit that allows relative movement in the direction.

FIG. 3 is an explanatory diagram showing the constituent members of the main parts of the vehicle differential gear at intervals in the axial direction. FIG. 4 is a cross-sectional view showing the operating state of the differential device 1 when the vehicle is traveling forward; (a) shows the operating state of the differential device 1 during acceleration, and (b) shows the operating state of the differential device 1 during deceleration. 1, respectively. In addition, in FIG. 4, for clarity of explanation, the amount of movement of each member in the axial direction and the size of the axial gap generated between each member are shown in an exaggerated manner than in reality.

The first connecting member 51 has a first outer annular protrusion 513 that protrudes toward the first side gear 41 on one axial side (first side washer 61 side) of the first coupling portion _J1 , and has a first outer annular projection 513 that protrudes toward the first side gear 41. The annular projection 513 is fitted into the inner peripheral fitting surface 41a of the first side gear 41 with a pilot fitting. An axial gap is formed between the plurality of helical spline teeth 512 and the first outer annular projection 513, and this gap facilitates machining of the helical spline teeth 512.

The first outer annular projection 513 protrudes radially outward from the outer circumferential surface 51a (see FIG. 3) in the gap with the plurality of helical spline teeth 512, and the tip surface 513a of the first outer annular projection 513 is connected to the first side gear. It faces the inner peripheral fitting surface 41a of 41. The outer diameter of the tip surface 513a of the first outer annular projection 513 is slightly smaller than the inner diameter of the inner peripheral fitting surface 41a of the first side gear 41. Hereinafter, the fitting portion between the first outer annular projection 513 and the inner peripheral fitting surface 41a of the first side gear 41 will be referred to as the first outer fitting portion _F11 .

The first side gear 41 has a first inner annular protrusion 413 that protrudes toward the first connecting member 51 on the other axial side (the center washer 60 side) of the first coupling portion _J1 . 413 is fitted into the outer circumferential fitting surface 51b of the first connecting member 51 with a spigot. An axial gap is formed between the plurality of helical spline teeth 412 and the first inner annular projection 413, and this gap facilitates machining of the helical spline teeth 412.

The first inner annular projection 413 protrudes radially inward from the inner circumferential surface 41b (see FIG. 3) in the gap with the plurality of helical spline teeth 412, and the distal end surface 413a of the first inner annular projection 413 is the first inner annular projection 413. It faces the outer circumferential fitting surface 51b of the connecting member 51. The inner diameter of the distal end surface 413a of the first inner annular projection 413 is slightly larger than the outer diameter of the outer peripheral fitting surface 51b of the first connecting member 51. Hereinafter, the fitting portion between the first inner annular projection 413 and the outer peripheral fitting surface 51b of the first connecting member 51 will be referred to as the first inner fitting portion _F12 .

The second connecting member 52 has a second outer annular protrusion 523 that protrudes toward the _second side gear 42 on one axial side (the second side washer 62 side) of the second coupling portion J2. The annular projection 523 is fitted into the inner peripheral fitting surface 42a of the second side gear 42 with a pilot fitting. An axial gap is formed between the plurality of helical spline teeth 522 and the second outer annular projection 523.

The second outer annular projection 523 protrudes radially outward from the outer circumferential surface 52a (see FIG. 3) in the gap with the plurality of helical spline teeth 522, and the tip surface 523a of the second outer annular projection 523 is connected to the second side gear. 42 facing the inner circumferential fitting surface 42a. The outer diameter of the tip surface 523a of the second outer annular projection 523 is slightly smaller than the inner diameter of the inner peripheral fitting surface 42a of the second side gear 42. Hereinafter, the fitting portion between the second outer annular projection 523 and the inner peripheral fitting surface 42a of the second side gear 42 will be referred to as a second outer fitting portion _F21 .

The second side gear 42 has a second inner annular protrusion 423 that protrudes toward the second connecting member 52 on the other axial side (the center washer 60 side) of the second coupling portion _J2 . 423 is fitted into the outer circumferential fitting surface 52b of the second connecting member 52 with a spigot. An axial gap is formed between the plurality of helical spline teeth 422 and the second inner annular projection 423.

The second inner annular projection 423 protrudes radially inward from the inner circumferential surface 42b (see FIG. 3) in the gap with the plurality of helical spline teeth 422, and the tip surface 423a of the second inner annular projection 423 is the second inner annular projection 423. It faces the outer circumferential fitting surface 52b of the connecting member 52. The inner diameter of the distal end surface 423a of the second inner annular projection 423 is formed to be slightly larger than the outer diameter of the outer circumferential fitting surface 52b of the second connecting member 52. Hereinafter, the fitting portion between the second inner annular projection 423 and the outer peripheral fitting surface 52b of the second connecting member 52 will be referred to as the second inner fitting portion _F22 .

In this way, the first connecting member 51 and the first side gear 41 are spigot-fitted at the first outer fitting portion F ₁₁ and the first inner fitting portion F ₁₂ that sandwich the first coupling portion J ₁ in the axial direction. Therefore, the first connecting member 51 is prevented from tilting with respect to the first side gear 41. In addition, the second connecting member 52 and the second side gear 42 are spigot-fitted at the second outer fitting portion F ₂₁ and the second inner fitting portion F ₂₂ that sandwich the second coupling portion J ₂ in the axial direction. The second connecting member 52 is prevented from tilting with respect to the second side gear 42.

Further, in this embodiment, the first connecting member 51 is provided with a first annular wall portion 514 that protrudes further radially outward from the tip surface 513a of the first outer annular projection 513. The first annular wall portion 514 is provided at the end of the first connecting member 51 on the first side washer 61 side, and axially faces the axial end surface 41c of the first side gear 41 on the first side washer 61 side. It has an inner side surface 514a and an outer side surface 514b facing the friction surface 61a of the first side washer 61 in the axial direction. An axial end surface 41d of the first side gear 41 on the center washer 60 side faces the first friction surface 60a of the center washer 60.

The axial end surface 510a of the first connecting member 51 on the side of the first side washer 61 has friction that comes into contact with the friction surface 61a of the first side washer 61 when the first connecting member 51 moves in a direction away from the center washer 60. It has a surface 510b and a recessed surface 510c that is slightly recessed in the axial direction from the friction surface 510b and does not come into contact with the first side washer 61. The entire outer side surface 514b of the first annular wall portion 514 is included in the friction surface 510b. The friction surface 510b and the recessed surface 510c are annularly provided over the entire circumferential direction of the first connecting member 51, and the area of the friction surface 510b is larger than the area of the recessed surface 510c, and the friction surface 510b is larger than the area of the recessed surface 510c. formed on the outside. However, the entire axial end surface 510a may be the friction surface 510b without providing a step on the axial end surface 510a.

Similarly, the second connecting member 52 is provided with a second annular wall portion 524 that protrudes further radially outward from the distal end surface 523a of the second outer annular projection 523. The second annular wall portion 524 is provided at the end of the second connecting member 51 on the second side washer 62 side, and axially faces the axial end surface 42c of the second side gear 42 on the second side washer 62 side. It has an inner side surface 524a and an outer side surface 524b facing the friction surface 62a of the second side washer 62 in the axial direction. An axial end surface 42d of the second side gear 42 on the center washer 60 side faces the second friction surface 60b of the center washer 60.

The axial end surface 520a of the second connecting member 52 on the second side washer 62 side has friction that comes into contact with the friction surface 62a of the second side washer 62 when the second connecting member 52 moves in a direction away from the center washer 60. It has a surface 520b and a recessed surface 520c that is slightly recessed in the axial direction from the friction surface 520b and does not come into contact with the second side washer 62. The entire outer side surface 524b of the second annular wall portion 524 is included in the friction surface 520b. The friction surface 520b and the recessed surface 520c are annularly provided over the entire circumferential direction of the second connecting member 52, and the area of the friction surface 520b is larger than the area of the recessed surface 520c, and the friction surface 520b is larger than the area of the recessed surface 520c. formed on the outside. However, the entire axial end surface 520a may be the friction surface 520b without providing a step on the axial end surface 520a.

Note that when assembling the first connecting member 51 to the first side gear 41, the first connecting member 51 is inserted into the inside of the first side gear 41 from the axial end surface 41c side of the first side gear 41. Furthermore, when assembling the second connecting member 52 to the second side gear 42, the second connecting member 52 is inserted into the inside of the second side gear 42 from the axial end surface 42c side of the second side gear 42.

When the vehicle accelerates in the forward direction (hereinafter referred to as driving time), the friction surface 510b of the first connecting member 51 is pressed against the friction surface 61a of the first side washer 61, as shown in FIG. 4(a). At the same time, the axial end surface 41d of the first side gear 41 is pressed against the first friction surface 60a of the center washer 60. The axial thrust force acting on the first connecting member 51 is due to the engagement between the helical spline teeth 512 of the first connecting member 51 and the helical spline teeth 412 of the first side gear 41. The axial thrust force acting on the first side gear 41 is generated by the engagement between the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51, and by the force formed on the outer peripheral surface of the first side gear 41. This is due to the engagement between the oblique teeth 411 and the large diameter gear portion 311 of the first pinion gear 31.

Similarly, during driving, as shown in FIG. 4(a), the friction surface 520b of the second connecting member 52 is pressed against the friction surface 62a of the second side washer 61, and the axial end surface 42d of the second side gear 42 is pressed against the friction surface 62a of the second side washer 61. It is pressed against the second friction surface 60b of the center washer 60. The axial thrust force acting on the second connecting member 52 is due to the engagement between the helical spline teeth 522 of the second connecting member 52 and the helical spline teeth 422 of the second side gear 42 . The axial thrust force acting on the second side gear 42 is generated by the engagement between the helical spline teeth 422 of the second side gear 42 and the helical spline teeth 522 of the second connecting member 52, and by the force formed on the outer peripheral surface of the second side gear 42. This is due to the engagement between the oblique teeth 421 and the second pinion gear 32.

On the other hand, when the vehicle is decelerating (hereinafter referred to as coasting), the axial end surface 41d of the first side gear 41 separates from the center washer 60, as shown in FIG. 4(b). Further, the axial end surface 41c of the first side gear 41 abuts the inner side surface 514a of the first annular wall portion 514, thereby causing the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51 to Thrust force due to meshing is no longer generated. Further, the first connecting member 51 receives thrust force generated by the engagement between the oblique teeth 411 of the first side gear 41 and the large diameter gear portion 311 of the first pinion gear 31 from the inner side surface 514a of the first annular wall portion 514, The friction surface 510b is pressed against the friction surface 61a of the first side washer 61.

Similarly, during coasting, the axial end surface 42d of the second side gear 42 separates from the center washer 60, as shown in FIG. 4(b). Further, the axial end surface 42c of the second side gear 42 comes into contact with the inner side surface 524a of the second annular wall portion 524, so that the helical spline teeth 422 of the second side gear 42 and the helical spline teeth 522 of the second connecting member 52 are in contact with each other. Thrust force due to meshing is no longer generated. Further, the second connecting member 52 receives the thrust force generated by the engagement between the oblique teeth 421 of the second side gear 42 and the second pinion gear 32 from the inner side surface 524a of the second annular wall portion 524, and the friction surface 520b It is pressed against the friction surface 62a of the side washer 62.

During driving, the friction force generated between the friction surface 510b of the first connecting member 51 and the friction surface 61a of the first side washer 61, and the first friction between the axial end surface 41d of the first side gear 41 and the center washer 60. The frictional force generated between the first side gear 41 and the first connecting member 51 becomes a frictional resistance force that suppresses relative rotation of the first side gear 41 and the first connecting member 51 with respect to the differential case 2. Further, the friction force generated between the friction surface 520b of the second connecting member 52 and the friction surface 62a of the second side washer 62, and the axial end surface 42d of the second side gear 42 and the second friction surface 60b of the center washer 60 The frictional force generated between them becomes a frictional resistance force that suppresses relative rotation of the second side gear 42 and the second connecting member 52 with respect to the differential case 2. These frictional resistance forces become a differential limiting force that limits the differential rotation of the pair of output shafts 71 and 72 during driving.

In this embodiment, the outer side surface 514b of the first annular wall portion 514 included in the friction surface 510b of the first connecting member 51 comes into contact with the friction surface 61a of the first side washer 61 to generate a frictional force. Compared to the case where the first annular wall portion 514 is not provided, the contact area between the first connecting member 51 and the friction surface 61a of the first side washer 61 can be increased, and seizure and wear can be suppressed. Similarly, since the outer side surface 524b of the second annular wall portion 524 included in the friction surface 520b of the second connecting member 52 comes into contact with the friction surface 62a of the second side washer 62 to generate a frictional force, the second annular wall Compared to the case where the portion 524 is not provided, the contact area between the second connecting member 52 and the friction surface 62a of the second side washer 62 can be increased, and seizure and wear can be suppressed.

In particular, in this embodiment, since the friction surface 510b is increased toward the outer diameter side by the outer side surface 514b of the first annular wall portion 514, the frictional force with the friction surface 61a of the first side washer 61 causes T( Based on the relationship: (torque) = F (force) x R (distance from the axis of rotation to the point where force is applied), a larger differential limiting force can be generated. The same applies to the second annular wall portion 524 of the second connecting member 52.

Furthermore, in this embodiment, the axial end surface 41d of the first side gear 41 that comes into contact with the first friction surface 60a of the center washer 60 is formed in a range that includes the side surface of the first inner annular projection 413. The contact area between the first side gear 41 and the first friction surface 60a of the center washer 60 is expanded, and seizure and wear are suppressed. Similarly, the axial end surface 42d of the second side gear 42 that comes into contact with the second friction surface 60b of the center washer 60 is formed in a range that includes the side surface of the second inner annular projection 423, so that the second side gear 42 and the center The contact area of the washer 60 with the second friction surface 60b is expanded, and seizure and wear are suppressed.

On the other hand, during coasting, the frictional force generated between the frictional surface 510b of the first connecting member 51 and the frictional surface 61a of the first side washer 61 is a frictional resistance force that suppresses the relative rotation of the first connecting member 51 with respect to the differential case 2. Therefore, the frictional force generated between the frictional surface 520b of the second connecting member 52 and the frictional surface 62a of the second side washer 62 becomes a frictional resistance force that suppresses the relative rotation of the second connecting member 52 with respect to the differential case 2. These frictional resistance forces become a differential limiting force that limits the differential rotation of the pair of output shafts 71 and 72 during coasting.

The fitted states of the first outer fitting part F ₁₁ , the first inner fitting part F ₁₂ , the second outer fitting part F ₂₁ , and the second inner fitting part F ₂₂ during both driving and coasting is maintained, and the inclination of the first connecting member 51 with respect to the first side gear 41 and the inclination of the second connecting member 52 with respect to the second side gear 42 are suppressed. Further, during coasting, thrust force due to meshing between the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51, and the helical force between the helical spline teeth 422 of the second side gear 42 and the second connecting member 52 are generated. Since no thrust force is generated due to engagement with the spline teeth 522, the differential limiting force that limits the differential rotation of the pair of output shafts 71 and 72 is smaller than during driving.

Note that the first annular wall portion 514 of the first connecting member 51 and the second annular wall portion 524 of the second connecting member 52 may be omitted. In this case, even during coasting, the first side gear 41 and the first connecting member 51 are rotated in opposite directions due to the thrust force caused by the engagement between the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51. The second side gear 42 and the second connecting member 52 are pressed in opposite directions by the thrust force caused by the engagement between the helical spline teeth 422 of the second side gear 42 and the helical spline teeth 522 of the second connecting member 52. Therefore, differential limiting force similar to that during driving is generated.

(Comparative example)
FIG. 5A is a sectional view showing a comparative example in which the first side gear 41 is not provided with the first inner annular projection 413 and the second side gear 42 is not provided with the second inner annular projection 423. be. In FIG. 5(a), components common to the above embodiments are designated by the same reference numerals as those in FIGS. 1 to 4, and redundant explanation will be omitted.

In this comparative example, although the first connecting member 51 and the first side gear 41 are spigot-fitted in the first outer fitting part _F11 on the first side washer 61 side of the first joint part _J1 , On the center washer 60 side of the joint _J1 , the first connecting member 51 and the first side gear 41 are not fitted with a spigot. In addition, although the _second connecting member 52 and the second side gear 42 are fitted with a spigot in the second outer fitting portion _F21 on the second side washer 62 side of the second connecting portion J2, the second connecting portion J On the center washer 60 side of _{No. 2} , the second connecting member 52 and the second side gear 42 are not fitted with a spigot. Therefore, compared to the present embodiment, the first connecting member 51 is more likely to tilt with respect to the first side gear 41, and the second connecting member 52 is more likely to be tilted with respect to the second side gear 42. FIG. 5A shows a state in which the first connecting member 51 is inclined with respect to the first side gear 41 and the second connecting member 52 is inclined with respect to the second side gear 42, with the angle of inclination exaggerated. .

FIGS. 5(b) to 5(d) are explanatory diagrams showing the meshing portion between the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51, and FIG. (c) is a cross-sectional view taken along line AA, (c) is a cross-sectional view taken along line BB in (a), and (d) is a cross-sectional view taken along line CC in (a). As shown in FIGS. 5(b) to 5(d), when the first connecting member 51 is tilted with respect to the first side gear 41, parts of the helical spline teeth 412, 512 where the engagement is loose at both ends in the axial direction A tough part will occur. This reduces the hysteresis of the differential limiting force when it changes from the expected value, or when changing from drive (acceleration) state to coast (deceleration) state, or when changing from coasting state to drive state. Problems such as increase in size may occur.

(Effects of embodiment)
In the present embodiment, the first connecting member 51 and the first side gear 41 are fitted with pilots at two locations sandwiching the first joint _J1 in the axial direction, so that the first connecting member 51 is connected to the first side gear 41. It is suppressed from tilting with respect to. Further, since the second connecting member 52 and the second side gear 42 are fitted with pilots at two locations sandwiching the second joint J ₂ in the axial direction, the second connecting member 52 is inclined with respect to the second side gear 42. things are suppressed. Thereby, the helical spline teeth 412 of the first side gear 41 and the helical spline teeth 512 of the first connecting member 51 mesh with each other, and the helical spline teeth 422 of the second side gear 42 and the helical spline teeth 522 of the second connecting member 52 mesh with each other. The meshing becomes appropriate, and an appropriate differential limiting force can be exerted, and hysteresis of the differential limiting force at the time of switching between the drive state and the coasting state can be suppressed.

(Additional note)
Although the present invention has been described above based on the embodiments, the embodiments do not limit the invention according to the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are essential for solving the problems of the invention.

Moreover, the present invention can be implemented with appropriate modifications by omitting some configurations, or adding or replacing configurations, without departing from the spirit thereof. For example, in the above embodiment, a case has been described in which the pinion gear set 3 has one first pinion gear 31 and two second pinion gears 32, but the present invention is not limited to this. A pinion gear set may be configured by meshing with the second pinion gear 32.

1... Vehicle differential device 2... Differential case 3... Pinion gear set 31... First pinion gear 32... Second pinion gear 41... First side gear 41a... Inner circumference fitting surface 42... Second side gear 42a... Inner circumference fitting surface 51... First connecting member 513...First outer annular projection 51b...Outer periphery fitting surface 52...Second connecting member 523...Second outer annular projection 52b...Outer periphery fitting surface

Claims (2)

A vehicle differential device that distributes the driving force of a vehicle to a pair of output shafts while allowing a differential,
a first connecting member that is non-rotatably connected to one of the pair of output shafts;
a second connecting member that is connected to the other output shaft of the pair of output shafts in a relatively non-rotatable manner;
a first side gear coupled to the first connecting member by a helical spline at a first coupling portion;
a second side gear connected to the second connecting member by a helical spline at a second connecting portion;
a plurality of pinion gear sets formed by meshing a first pinion gear that meshes with the first side gear and a second pinion gear that meshes with the second side gear;
a differential case that holds the plurality of pinion gear sets;
The first connecting member and the first side gear are spigot-fitted at two locations sandwiching the first coupling portion in the axial direction,
The second connecting member and the second side gear are spigot-fitted at two locations sandwiching the second coupling portion in the axial direction;
Vehicle differential device. The first connecting member has a first outer annular protrusion that protrudes toward the first side gear on one axial side of the first coupling part, and the first outer annular protrusion is connected to the inner periphery of the first side gear. The fitting surface is fitted with a spigot,
The first side gear has a first inner annular protrusion that protrudes toward the first connecting member on the other side in the axial direction of the first coupling part, and the first inner annular protrusion is arranged on the outer periphery of the first connecting member. The fitting surface is fitted with a spigot,
The second connecting member has a second outer annular protrusion that protrudes toward the second side gear on one axial side of the second coupling portion, and the second outer annular protrusion is connected to the inner periphery of the second side gear. The fitting surface is fitted with a spigot,
The second side gear has a second inner annular protrusion that protrudes toward the second connecting member on the other side in the axial direction of the second coupling portion, and the second inner annular protrusion extends along the outer periphery of the second connecting member. The mating surface is fitted with a spigot,
The vehicle differential device according to claim 1.

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