Differential

Abstract

To provide a differential gear capable of restricting differential operation in a simple construction.SOLUTION: The differential gear includes a pinion shaft, a first pinion gear and a second pinion gear, and a first restriction member and a second restriction member neighboring each other between the first pinion gear and the second pinion gear, the first restriction member and the second restriction member including a first cam and a second cam, respectively. When rotation torques are applied to the first restriction member and the second restriction member in the mutually opposite directions, the first cam and the second cam give axial forces to the first restriction member and the second restriction member in the mutually opposite directions, respectively. The first restriction member is fixed to the first pinion gear in the rotating direction. Between the second restriction member and the second pinion gear, a friction mechanism is provided.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In a vehicle, for example, a differential is used to absorb the rotation difference between the left and right drive wheels. However, for example, on a slippery road, if one of the drive wheels rotates freely while the other continues to contact the road, the differential transmits torque to the freely rotating drive wheel. In this case, the vehicle cannot run as intended. Therefore, in the technical field of vehicles, various configurations have been proposed to limit the differential operation of the differential (which may also be called LSD (Limited-slip differential)).

[0003] For example, Patent Document 1 discloses a device for limiting such differential operation. This device includes a pair of sleeves between a pair of pinion gears. The engagement portions of the pair of sleeves include cams that mesh with each other. When rotational torques in opposite directions are applied to the two pinion gears in response to the torque difference between the driving wheels, rotational torques in opposite directions are also applied to the two sleeves. When rotational torques in opposite directions are applied to the sleeves, axial forces in opposite directions are applied to the sleeves by the pair of cams along the axial direction of the pinion shaft. These axial forces press each pinion gear against the case. With this configuration, the rotation of each pinion gear is limited, thereby limiting the differential operation. Each pinion gear includes an oil groove to prevent seizure due to sliding between the pinion gears and the case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-49557 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device of Patent Document 1, since the pinion gear and the case slide against each other, it is necessary to provide an oil groove in the pinion gear (or the case) as described above. In addition, the contact surfaces of the pinion gear and the case need to be designed to allow sliding. Therefore, the design of the device of Patent Document 1 can be complicated.

[0006] In consideration of the above-mentioned problems, an object of the present invention is to provide a differential device capable of limiting differential operation with a simple configuration. [Means for solving the problem]

[0007] A differential device according to one aspect of the present invention comprises: A pinion shaft; a first pinion gear and a second pinion gear provided on the pinion shaft and spaced apart from each other in a central axial direction of the pinion shaft; a cylindrical first limiting member and a cylindrical second limiting member that are provided on the pinion shaft and are adjacent to each other between the first pinion gear and the second pinion gear in the central axis direction; Equipped with the first limiting member and the second limiting member each include a first cam and a second cam that mesh with each other; When a rotational torque in an opposite direction is applied to the first limiting member and the second limiting member, the first cam and the second cam generate axial forces in opposite directions along the central axis on the first limiting member and the second limiting member, respectively; the first limiting member is disposed adjacent to the first pinion gear and is fixed in a rotational direction relative to the first pinion gear, A friction mechanism is provided between the second limiting member and the second pinion gear, the friction mechanism generating friction torque between the second limiting member and the second pinion gear. Effect of the Invention

[0008] According to the present invention, it is possible to limit the differential operation with a simple configuration. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a differential gear according to an embodiment. [Diagram 2] FIG. 2 is a schematic enlarged view of part A in FIG. [Diagram 3] FIG. 3 is a schematic side view showing a first limiting member, a second limiting member, and a friction member according to the embodiment. [Figure 4] FIG. 4 is a schematic side view showing a friction member according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, values, etc. shown in the embodiment are merely examples for easy understanding, and do not limit the present invention unless otherwise specified. In the specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanation. In addition, elements not directly related to the present invention are not shown.

[0011] 1 is a schematic cross-sectional view showing a differential gear 1 according to an embodiment, showing the differential gear 1 from above. For example, the differential gear 1 is mounted on a vehicle 100 such as a hybrid electric vehicle (HEV), a gasoline-powered automobile, or a diesel-powered automobile. Note that arrow F indicates the forward direction of the vehicle 100, arrow B indicates the reverse direction of the vehicle 100, arrow R indicates the rightward direction of the vehicle 100, and arrow L indicates the leftward direction of the vehicle 100.

[0012] The differential gear 1 is provided in a housing 3. A shaft 5 connected to a power source (not shown, for example, an engine or a motor) is provided in the housing 3. The shaft 5 rotates by a driving force transmitted from the power source. An output gear 5a is provided at an end of the shaft 5. The output gear 5a rotates integrally with the shaft 5.

[0013] The differential device 1 includes a case 10. The case 10 is rotatably supported by the housing 3 via a bearing BB. The case 10 includes a main body portion 10a and a flange portion 10b.

[0014] The main body portion 10a has a generally cylindrical shape and has a central axis extending in the LR direction. The main body portion 10a defines a gear chamber 14.

[0015] The flange portion 10b has a generally disk shape and is arranged concentrically with the main body portion 10a. That is, the flange portion 10b has a central axis extending in the LR direction. The flange portion 10b protrudes radially outward from the outer surface of the main body portion 10a. For example, the flange portion 10b is integrally formed with the outer surface of the main body portion 10a.

[0016] A ring gear 12 that meshes with the output gear 5a is attached to the flange portion 10b. The case 10 rotates about an axis extending in the LR direction by the rotational power input from the shaft 5 via the output gear 5a and the ring gear 12.

[0017] The main body 10a includes a pair of through holes 10c. The central axes of the pair of through holes 10c coincide with each other and extend in a direction perpendicular to the central axis of the main body 10a (i.e., the FB direction). A pinion shaft 16 is inserted into the through hole 10c. Both ends of the pinion shaft 16 are supported by the through hole 10c. The gear chamber 14 accommodates the central portion of the pinion shaft 16.

[0018] The main body 10a includes a pin hole 10d. The pin hole 10d extends in a direction parallel to the central axis of the main body 10a (i.e., the LR direction). The pin hole 10d intersects with and communicates with one of the through holes 10c (the upper through hole 10c in FIG. 1). The pin hole 10d is formed radially outward with respect to the gear chamber 14.

[0019] The pinion shaft 16 includes a communication hole 16a at a position corresponding to the pin hole 10d. Therefore, the communication hole 16a is continuous with the pin hole 10d. A pin P is inserted into the pin hole 10d and the communication hole 16a. The pin P restricts the movement of the pinion shaft 16 in the axial and rotational directions.

[0020] A first pinion gear 18a and a second pinion gear 18b are provided on the pinion shaft 16. The first pinion gear 18a and the second pinion gear 18b are rotatably supported by the pinion shaft 16. The first pinion gear 18a and the second pinion gear 18b are housed in the gear chamber 14.

[0021] The first pinion gear 18a and the second pinion gear 18b are spaced apart from each other along the central axis of the pinion shaft 16. A first limiting member 23a, a second limiting member 23b, and a friction member 24 are provided on the pinion shaft 16 between the first pinion gear 18a and the second pinion gear 18b (described in detail below).

[0022] The main body 10a includes a pair of through holes 10e. The central axes of the pair of through holes 10e coincide with each other and coincide with the central axis of the main body 10a. That is, the central axis of the through holes 10e extends in the L-R direction. Side gears 20L and 20R are inserted into the pair of through holes 10e, respectively. Each of the side gears 20L and 20R is rotatably supported in the through holes 10e. The side gears 20L and 20R are housed in a gear chamber 14.

[0023] The side gear 20L is disposed on one side of the main body 10a in the central axial direction relative to the first pinion gear 18a and the second pinion gear 18b, and meshes with the first pinion gear 18a and the second pinion gear 18b. The side gear 20R is disposed on the other side of the main body 10a in the central axial direction relative to the first pinion gear 18a and the second pinion gear 18b, and meshes with the first pinion gear 18a and the second pinion gear 18b.

[0024] A drive wheel shaft 22L is attached to the side gear 20L. The central axis of the drive wheel shaft 22L coincides with the central axis of the main body 10a. The drive wheel shaft 22L rotates integrally with the side gear 20L. Similarly, a drive wheel shaft 22R is attached to the side gear 20R. The central axis of the drive wheel shaft 22R coincides with the central axis of the main body 10a. The drive wheel shaft 22R rotates integrally with the side gear 20R. The drive wheel shafts 22L and 22R are each provided with a wheel (not shown).

[0025] In the differential 1 as described above, when the shaft 5 and the output gear 5a are rotated together by the driving force from the power source, the output gear 5a rotates the ring gear 12. When the ring gear 12 rotates, the case 10 rotates together with the ring gear 12.

[0026] For example, when the vehicle 100 runs linearly, the pinion shaft 16, the first pinion gear 18a, and the second pinion gear 18b rotate (revolve) together with the case 10 around the central axis of the main body 10a. When the first pinion gear 18a and the second pinion gear 18b revolve around the central axis of the main body 10a, the side gears 20L, 20R rotate together with the first pinion gear 18a and the second pinion gear 18b. When the side gears 20L, 20R rotate together with each other, the drive wheel shafts 22L, 22R rotate together with the side gears 20L, 20R. Therefore, the left and right drive wheels rotate at the same rotation speed.

[0027] For example, when the vehicle 100 turns left or right, the left and right drive wheels (i.e., drive wheel shafts 22L, 22R) rotate at different rotational speeds. When the drive wheel shafts 22L, 22R rotate at different rotational speeds, the side gears 20L, 20R also rotate at different rotational speeds. When the side gears 20L, 20R rotate at different rotational speeds, the first pinion gear 18a and the second pinion gear 18b rotate in opposite directions around the pinion shaft 16. With this configuration, the rotational difference between the side gears 20L, 20R is absorbed by the first pinion gear 18a and the second pinion gear 18b, thereby distributing torque to each wheel according to its respective rotational speed.

[0028] Next, the first limiting member 23a, the second limiting member 23b, and the friction member (friction mechanism) 24 will be described in detail.

[0029] Fig. 2 is a schematic enlarged view of part A in Fig. 1. As described above, the pinion shaft 16 is provided with the first limiting member 23a, the second limiting member 23b, and the friction member 24 between the first pinion gear 18a and the second pinion gear 18b.

[0030] Each of the first limiting member 23a and the second limiting member 23b has a cylindrical shape. The first limiting member 23a and the second limiting member 23b are concentrically disposed around the pinion shaft 16. The inner diameters of the first limiting member 23a and the second limiting member 23b match (or nearly match) each other and are slightly larger than the outer diameter of the pinion shaft 16. The first limiting member 23a and the second limiting member 23b are rotatably disposed around the pinion shaft 16. The outer diameters of the first limiting member 23a and the second limiting member 23b are dimensioned so as not to contact the drive wheel shafts 22L, 22R.

[0031] Regarding the length in the central axis direction of the pinion shaft 16, for example, the first limiting member 23a is longer than the second limiting member 23b by the length of the friction member 24 and the protrusion 23d (described in detail later). The lengths of the first limiting member 23a and the second limiting member 23b are not limited thereto, and for example, the second limiting member 23b may be longer than the first limiting member 23a. In the central axis direction of the pinion shaft 16, the first limiting member 23a and the second limiting member 23b are disposed adjacent to each other. In the central axis direction of the pinion shaft 16, the first limiting member 23a is disposed adjacent to the first pinion gear 18a. In the central axis direction of the pinion shaft 16, the friction member 24 is disposed between the second limiting member 23b and the second pinion gear 18b. The first pinion gear 18a, the first limiting member 23a, the second limiting member 23b, the friction member 24, and the second pinion gear 18b are sized to contact one another in the central axial direction of the pinion shaft 16. Thus, the axial movements of the first limiting member 23a, the second limiting member 23b, and the friction member 24 are limited by the first pinion gear 18a and the second pinion gear 18b.

[0032] 3 is a schematic side view showing the first limiting member 23a, the second limiting member 23b, and the friction member 24 according to the embodiment. The first limiting member 23a includes one or more protrusions 23d on an end surface 23c facing the first pinion gear 18a (not shown in FIG. 3). In this embodiment, the first limiting member 23a includes two protrusions 23d. In other embodiments, the first limiting member 23a may include a single protrusion 23d or three or more protrusions 23d. The two protrusions 23d are provided spaced apart from each other, for example, 180 degrees, in the circumferential direction of the first limiting member 23a.

[0033] 2, the first pinion gear 18a includes a groove 18c at a position corresponding to the above-mentioned protrusion 23d. The groove 18c is configured to receive the protrusion 23d. Therefore, the first limiting member 23a is fixed to the first pinion gear 18a in the rotation direction of the first pinion gear 18a. That is, the first limiting member 23a rotates integrally with the first pinion gear 18a.

[0034] 3, the first limiting member 23a and the second limiting member 23b include a first cam 23e and a second cam 23f, respectively, which mesh with each other. As shown in the right diagram of FIG. 3, the first cam 23e and the second cam 23f are configured to generate axial forces Fa in opposite directions along the central axis of the pinion shaft 16 on the first limiting member 23a and the second limiting member 23b, respectively, when rotational torques in opposite directions are applied to the first limiting member 23a and the second limiting member 23b, respectively. Note that in the right diagram of Figure 3, the gap between the first limiting member 23a and the second limiting member 23b is exaggerated for better understanding, but the actual gap may be zero (or may be extremely small), because the axial movement of the first limiting member 23a and the second limiting member 23b is limited by the first pinion gear 18a and the second pinion gear 18b (not shown in Figure 3) as described above.

[0035] Specifically, the first cam 23e includes a plurality of protrusions 23g along the circumferential direction. An edge 23h connecting the apex and the valley of the protrusion 23g is inclined with respect to the central axis of the first restricting member 23a. For example, the edge 23h has a straight line shape. In this embodiment, the inclination angle of the edge 23h is 45 degrees, but is not limited thereto. In other embodiments, the edge 23h may have a curved shape.

[0036] The second cam 23f has a shape complementary to the first cam 23e. Specifically, the second cam 23f includes a plurality of protrusions 23i along the circumferential direction. An edge 23j connecting the apex and the valley of the protrusion 23i is inclined with respect to the central axis of the second restricting member 23b and is formed to correspond to the edge 23h of the first restricting member 23a. For example, the edge 23j has a linear shape. In this embodiment, the inclination angle of the edge 23j is 45 degrees, but is not limited to this. In other embodiments, the edge 23j may have a curved shape.

[0037] The first limiting member 23a and the second limiting member 23b are formed of a metal such as iron.

[0038] The friction member 24 is configured to generate a friction torque (friction force) between the second limiting member 23b and the second pinion gear 18b in response to the axial force Fa from the first cam 23e and the second cam 23f. For example, the friction member 24 has an annular or cylindrical shape and is disposed concentrically around the pinion shaft 16. In this embodiment, the friction member 24 includes a main body 24a and two friction sheets 24b.

[0039] The main body 24a has a circular ring shape or a cylindrical shape and is made of a metal such as iron.

[0040] The friction sheet 24b is attached to both end surfaces of the main body 24a. For example, the friction sheet 24b includes a base material including pulp fiber, aramid fiber, carbon, or the like, and a binder made of a synthetic resin such as a phenolic resin. For example, the friction sheet 24b may be formed in the same manner as a wet clutch facing used in an automobile.

[0041] For example, the maximum static friction torque Tmax between the second limiting member 23b and the second pinion gear 18b provided by the friction member 24 is adjusted to, for example, about 20 N·m in this embodiment. For example, the maximum static friction torque Tmax can be adjusted by changing the type or area of ​​the friction sheet 24b. For example, the maximum static friction torque Tmax can be determined by gradually increasing the torque difference between the left and right driving wheels (or the driving wheel shafts 22L, 22R) and measuring the torque difference when the differential device 1 starts the differential operation (i.e., when the restriction on the relative rotation between the first pinion gear 18a and the second pinion gear 18b described below is released). For example, when the measured values ​​fluctuate, the maximum static friction torque Tmax may be their average value.

[0042] Next, the operation of the differential device 1 will be described.

[0043] 1, for example, when the vehicle 100 encounters a sudden crosswind while traveling straight on a road such as an expressway or a bridge, the contact pressure between one of the left and right drive wheels and the ground decreases, and the contact pressure between the other drive wheel and the ground increases. In this case, the torques applied to the drive wheel shafts 22L, 22R (i.e., the torques applied to the side gears 20L, 20R) are different from each other. Therefore, the first pinion gear 18a and the second pinion gear 18b are subjected to rotational torques in opposite directions.

[0044] 2, the first pinion gear 18a and the first limiting member 23a are fixed to each other in the rotational direction by the engagement of the protrusion 23d and the groove 18c. In addition, when the rotational torque is equal to or less than the maximum static friction torque Tmax (20 N in this embodiment), the second pinion gear 18b and the second limiting member 23b are also fixed to each other in the rotational direction by the friction torque from the friction member 24. Therefore, as described above, when a rotational torque in the opposite direction is applied to the first pinion gear 18a and the second pinion gear 18b, the rotational torque in the opposite direction is applied to the first limiting member 23a and the second limiting member 23b, respectively.

[0045] Referring to FIG. 3, when rotational torques in opposite directions are applied to the first limiting member 23a and the second limiting member 23b, respectively, a reaction between the first cam 23e and the second cam 23f causes an axial force Fa in the opposite direction to be applied along the central axis of the pinion shaft 16 to the first limiting member 23a and the second limiting member 23b, respectively.

[0046] Referring to FIG. 2, the axial force Fa (not shown in FIG. 2) is applied to the second pinion gear 18b from the second limiting member 23b via the friction member 24. Therefore, the second limiting member 23b, the friction member 24, and the second pinion gear 18b are locked to each other in the rotational direction by the friction torque from the friction member 24 caused by the axial force Fa. As described above, the axial movements of the first limiting member 23a and the second limiting member 23b are limited by the first pinion gear 18a and the second pinion gear 18b, so that the first limiting member 23a and the second limiting member 23b are locked to each other in the rotational direction by the engagement of the first cam 23e and the second cam 23f. Furthermore, the first limiting member 23a and the first pinion gear 18a are locked to each other in the rotational direction by the engagement of the protrusion 23d and the groove 18c. That is, all parts between the first pinion gear 18a and the second pinion gear 18b (the first pinion gear 18a, the first limiting member 23a, the second limiting member 23b, the friction member 24, and the second pinion gear 18b) are locked to each other in the rotational direction. Therefore, although a rotational torque in the opposite direction is applied to the first pinion gear 18a and the second pinion gear 18b, the relative rotation between the first pinion gear 18a and the second pinion gear 18b is limited by the friction torque from the friction member 24 caused by the axial force Fa. Thus, the differential operation is limited.

[0047] As described above, in the differential device 1, when the rotational torque applied to the first pinion gear 18a and the second pinion gear 18b is equal to or less than the maximum static friction torque Tmax (about 20 N·m in this embodiment), that is, when the torque difference between the left and right drive wheels is relatively small, the differential device 1 continues to distribute torque equally to the left and right drive wheels in a situation where the torque difference between the left and right drive wheels is relatively small, for example, when the vehicle 100 is subjected to a sudden crosswind while traveling straight on a road such as a highway or a bridge. Therefore, the driving stability is improved.

[0048] When the rotational torque applied to the first pinion gear 18a and the second pinion gear 18b exceeds the maximum static friction torque Tmax, the second pinion gear 18b overcomes the friction torque from the friction member 24 and starts to rotate in the opposite direction to the first pinion gear 18a. Therefore, the differential device 1 starts a differential operation.

[0049] The differential device 1 as described above includes the pinion shaft 16, the first pinion gear 18a and the second pinion gear 18b provided on the pinion shaft 16 and spaced apart from each other in the central axis direction of the pinion shaft 16, and the cylindrical first limiting member 23a and the second limiting member 23b provided on the pinion shaft 16 and adjacent to each other between the first pinion gear 18a and the second pinion gear 18b in the central axis direction. The first limiting member 23a and the second limiting member 23b include a first cam 23e and a second cam 23f that mesh with each other, respectively, and when a rotational torque in an opposite direction is applied to the first limiting member 23a and the second limiting member 23b, the first cam 23e and the second cam 23f generate an axial force Fa in an opposite direction along the central axis of the pinion shaft 16 on the first limiting member 23a and the second limiting member 23b, respectively. The first limiting member 23a is disposed adjacent to the first pinion gear 18a and is fixed in the rotational direction relative to the first pinion gear 18a. A friction member 24 is provided between the second limiting member 23b and the second pinion gear 18b to generate a friction torque between the second limiting member 23b and the second pinion gear 18b. In such a differential device 1, when a rotational torque in the opposite direction is applied to the first pinion gear 18a and the second pinion gear 18b (i.e., when a torque difference occurs between the left and right driving wheels), an axial force Fa in the opposite direction is applied to the first limiting member 23a and the second limiting member 23b by the first cam 23e and the second cam 23f along the central axis of the pinion shaft 16. The second limiting member 23b, the friction member 24, and the second pinion gear 18b are locked to each other in the rotational direction by the friction torque from the friction member 24 caused by the axial force Fa. Also, the first limiting member 23a and the second limiting member 23b are locked to each other in the rotational direction by the engagement of the first cam 23e and the second cam 23f. Furthermore, the first limiting member 23a is fixed to the first pinion gear 18a in the rotational direction. Therefore, the first pinion gear 18a, the first limiting member 23a, the second limiting member 23b, the friction member 24, and the second pinion gear 18b are all locked to each other in the rotational direction, and the differential operation is restricted.Therefore, the differential operation can be limited by a simple configuration in which the first limiting member 23a, the second limiting member 23b, and the friction member 24 are inserted between the first pinion gear 18a and the second pinion gear 18b. Furthermore, in the differential device 1, the limitation of the differential operation is completed by the parts between the first pinion gear 18a and the second pinion gear 18b. Therefore, complex design changes, such as a design change of the case 10, can be avoided.

[0050] In the differential 1, the friction member 24 includes at least one friction sheet 24b disposed between the second limiting member 23b and the second pinion gear 18b, and the at least one friction sheet 24b includes a base material and a binder made of a synthetic resin. For example, a readily available clutch facing used in automobiles can be used as the friction sheet 24b. In addition, when the friction sheet 24b is worn, the friction sheet 24b can be easily replaced.

[0051] In the differential device 1, the first limiting member 23a includes the protrusion 23d, and the first pinion gear 18a includes the groove 18c that engages with the protrusion 23d. With this configuration, the first pinion gear 18a and the first limiting member 23a can be prepared separately. Therefore, for example, the differential device 1 according to this embodiment can be easily applied to an existing vehicle 100 by simply forming the groove 18c in the first pinion gear 18a of the existing vehicle 100.

[0052] Although the embodiments have been described above with reference to the accompanying drawings, the present invention is not limited to such embodiments. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that such examples also naturally belong to the technical scope of the present invention.

[0053] For example, in the above embodiment, the friction member 24 including the friction sheet 24b is used as the friction mechanism. However, in other embodiments, the friction mechanism may include other parts. For example, FIG. 4 is a schematic side view showing a friction member 25 according to another embodiment. In this embodiment, a disc spring 25 is used as the friction mechanism. The disc spring 25 is made of a metal such as iron. In this embodiment, the disc spring 25 is made of metal, so that wear resistance can be improved.

[0054] 3, the friction member 24 includes the main body 24a and two friction sheets 24b. However, in other embodiments, the friction member 24 may include only one friction sheet 24b, and the friction sheet 24b may be directly attached to the end surface of the second restricting member 23b or the end surface of the second pinion gear 18b. In still other embodiments, the friction mechanism may be a rough surface formed directly on at least one of the end surface of the second restricting member 23b or the end surface of the second pinion gear 18b.

[0055] Also, for example, in the above embodiment, the first limiting member 23a includes the protrusion 23d, and the first pinion gear 18a includes the groove 18c. However, in other embodiments, the first pinion gear 18a may include a protrusion, and the first limiting member 23a may include a groove that receives the protrusion. In still other embodiments, the first limiting member 23a and the first pinion gear 18a may be integrally formed. [Explanation of symbols]

[0056] 1 Differential device 16 Pinion shaft 18a 1st pinion gear 18b 2nd pinion gear 18c groove 23a First limiting member 23b Second limiting member 23d protrusion 23e First Cam 23f 2nd Cam 24 Friction members (friction mechanisms) 24b Friction Sheet 25 Disc spring (friction mechanism) Fa Axial force

Claims

1. A pinion shaft; a first pinion gear and a second pinion gear provided on the pinion shaft and spaced apart from each other in a central axial direction of the pinion shaft; a first limiting member and a second limiting member each having a cylindrical shape and provided on the pinion shaft and adjacent to each other between the first pinion gear and the second pinion gear in the central axis direction; Equipped with the first limiting member and the second limiting member each include a first cam and a second cam that mesh with each other, When a rotational torque in an opposite direction is applied to the first limiting member and the second limiting member, the first cam and the second cam generate axial forces in opposite directions along the central axis on the first limiting member and the second limiting member, respectively; the first limiting member is disposed adjacent to the first pinion gear and is fixed in a rotational direction relative to the first pinion gear, a friction mechanism that generates a friction torque between the second limiting member and the second pinion gear is provided between the second limiting member and the second pinion gear; Differential device.

2. the friction mechanism includes at least one friction sheet disposed between the second limiting member and the second pinion gear, The at least one friction sheet includes a base material and a binder made of a synthetic resin. The differential device according to claim 1 .

3. 2. The differential gear according to claim 1, wherein the friction mechanism includes at least one metallic disc spring disposed between the second restricting member and the second pinion gear.

4. one of the first limiting member and the first pinion gear includes a protrusion, the other of the first limiting member and the first pinion gear includes a groove that engages with the protrusion; A differential device according to any one of claims 1 to 3.

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