Search

EP-4741684-A1 - VEHICLE DIFFERENTIAL DEVICE AND VEHICLE

EP4741684A1EP 4741684 A1EP4741684 A1EP 4741684A1EP-4741684-A1

Abstract

A vehicle differential device capable of adjusting a differential limiting torque with a simple configuration is provided. It includes: a differential case 40 rotated by receiving driving force of a rear drive motor 21; a pair of side gears 60 coaxial with a rotation axis O of the differential case; a pinion gear 52 meshing with both of the pair of the side gears; and a differential limiting mechanism 70 that generates differential limiting torque T for limiting differential motion of rear wheels 3 of a vehicle 1. The differential limiting mechanism has a plurality of friction plates 80 pressed by each side gear in an axial direction.

Inventors

  • OKA, NOBUYUKI
  • OHKAWA, YUZO

Assignees

  • MAZDA MOTOR CORPORATION

Dates

Publication Date
20260513
Application Date
20251107

Claims (14)

  1. A vehicle differential device to be mounted on a vehicle (1), the vehicle differential device comprising: a differential case (40) that is rotated by receiving a driving force of a drive source (21); a pair of side gears (60) that are disposed in the differential case (40) and coaxial with a rotation axis (O) of the differential case (40); a pinion gear (52) that is disposed in the differential case (40) and meshes with both of the pair of side gears (60); and a differential limiting mechanism (70) that generates a differential limiting torque (T) for limiting differential motion of wheels (2, 3) of the vehicle (1), wherein the differential limiting mechanism (70) comprises a plurality of friction plates (80) pressed by each side gear (60) in an axial direction (X) in which the rotation axis (O) extends, some of the plurality of friction plates (81) are a plurality of case-side friction plates (81) provided in the differential case (40), others of the plurality of friction plates (80) are a plurality of gear-side friction plates (82) provided in the side gear (60), the case-side friction plates (81) and the gear-side friction plates (82) are arranged side by side in the axial direction (X), and slide relative to each other to generate the differential limiting torque (T), characterized in that the case-side friction plates (81) include a first case-side friction plate (81A) and a second case-side friction plate (81B), the gear-side friction plates (82) include a first gear-side friction plate (82A) and a second gear-side friction plate (82B), and a first sliding diameter (EA) between the first case-side friction plate (81A) and the first gear-side friction plate (82A) and a second sliding diameter (EB) between the second case-side friction plate(81B) and the second gear-side friction plate (82B) are different from each other.
  2. The vehicle differential device according to claim 1, wherein a first inner diameter (dA) of the first case-side friction plate (81A) and a second inner diameter (dB) of the second case-side friction plate (81B) are different from each other.
  3. The vehicle differential device according to claim 1 or 2, wherein a first outer diameter (DA) of the first gear-side friction plate (82A) and a second outer diameter (DB) of the second gear-side friction plate (82B) are different from each other.
  4. The vehicle differential device according to any one of claims 1 to 3, wherein the differential limiting mechanism (70) includes a first differential limiting mechanism (71) arranged on one side of the pinion gear (52) in the axial direction (X), and a second differential limiting mechanism (72) arranged on another side of the pinion gear (52) in the axial direction (X), the first differential limiting mechanism (71) includes the first case-side friction plate (81A), the first gear-side friction plate (82A), the second case-side friction plate (81B) and the second gear-side friction plate(82B), and, in the first differential limiting mechanism (71), the first sliding diameter (EA) between the first case-side friction plate (81A) and the first gear-side friction plate (82A) and the second sliding diameter (EB) between the second case-side friction plate (81B) and the second gear-side friction plate (82B) are different from each other.
  5. The vehicle differential device according to any one of claims 1 to 4, wherein the differential limiting mechanism (70) comprises a first differential limiting mechanism (71) arranged on one side of the pinion gear (52) in the axial direction (X), and a second differential limiting mechanism (72) arranged on another side of the pinion gear (52) in the axial direction (X), the first differential limiting mechanism (71) includes the first case-side friction plate (81A) and the first gear-side friction plate (82A), the second differential limiting mechanism (72) includes the second case-side friction plate (81B) and the second gear-side friction plate (82B), and the first sliding diameter (EA) between the first case-side friction plate (81A) and the first gear-side friction plate (82A) in the first differential limiting mechanism (71) and the second sliding diameter (EB) between the second case-side friction plate (81B) and the second gear-side friction plate (82B) in the second differential limiting mechanism (72) are different from each other.
  6. The vehicle differential device according to any one of claims 1 to 5, wherein each of the side gears (60) has a gear main body (61) that meshes with the pinion gear (52), and a pressing body (62) that holds, together with the gear main body (61), the plurality of friction plates (80) therebetween, the gear main body (61) and the pressing body (62) are engaged with each other, and the gear-side friction plates (82) are mounted to the pressing body (62).
  7. The vehicle differential device according to claim 6, wherein the gear main body (61) and the pressing body (62) are engaged with each other by a spline fitting, such that rotation around the rotation axis (O) is restricted and movement in the axial direction (X) is permitted.
  8. The vehicle differential device according to claim 6 or 7, wherein one of the friction plates (80) has a thickness larger than the thickness of the other friction plates (80), and the friction plate (80) of larger thickness is arranged in contact with the gear main body (61) and with a disc spring (62e).
  9. The vehicle differential device according to any one of claims 1 to 8, wherein a disc spring (62e) is arranged between the pressing body (62) and the gear main body (61) of the side gear (60).
  10. The vehicle differential device according to any one of claims 6 to 9, wherein the differential limiting torque (T) for the right wheel and the differential limiting torque (T) for the left wheel are different.
  11. A vehicle (1) comprising a vehicle differential device according to any one of claims 1 to 10.
  12. The vehicle of claim 11, comprising a front drive unit (10) that rotates front wheels (2); and a rear drive unit (20) that rotates rear wheels (3) independently of the front drive unit (10), and having the vehicle differential device.
  13. The vehicle (1) according to claim 11, wherein the vehicle (1) is of a rear-wheel drive type or an all-wheel drive type, and wherein the vehicle differential device is used for differential control of rear wheels (3) of the vehicle (1).
  14. The vehicle (1) according to any one of claims 11 to 13, wherein the vehicle (1) is an electric vehicle.

Description

[Technical Field] The present disclosure relates to a vehicle differential device and a vehicle. [Background Art] Vehicle differential devices having differential limiting mechanisms are known. For example, a vehicle differential device disclosed in Patent Literature 1 includes: a differential case that is driven to rotate by a driving force of an engine; a differential gear mechanism that distributes the rotation of the differential case to wheel sides through a pair of side gears; a cone clutch that is formed between the differential case and a clutch member, is fastened by receiving a meshing reaction force of the side gear, and limits differential motion of the differential gear mechanism; and a cam mechanism that is provided between the clutch member and the side gear and presses the cone clutch by receiving the driving force. [Citation List] [Patent Literature] [Patent Literature 1] Japanese Unexamined Patent Publication No. H09-49560 [Summary of Invention] [Problems to be Solved by the Invention] When a differential limiting torque of the differential limiting mechanism is large, the stability of a vehicle while traveling in a straight line is improved, but it is difficult for the vehicle to turn. When the differential limiting torque of the differential limiting mechanism is small, it is easy for the vehicle to turn, but the stability of the vehicle while traveling in a straight line lowers. In order to balance the stability of the vehicle while traveling in a straight line and the ease of turning the vehicle, it is desired to adjust the differential limiting torque of the differential limiting mechanism in the vehicle differential device. The object of the present disclosure is to provide a vehicle differential device capable of adjusting the differential limiting torque with a simple configuration. [Means for Solving the Problems] A vehicle differential device according to the present disclosure is to be mounted on a vehicle, and includes: a differential case that is rotated by receiving a driving force of a drive source; a pair of side gears that are disposed in the differential case and coaxial with a rotation axis of the differential case; a pinion gear that is disposed in the differential case and meshes with both of the pair of side gears; and a differential limiting mechanism that generates a differential limiting torque for limiting differential motion of wheels of the vehicle, wherein the differential limiting mechanism has a plurality of friction plates that are pressed by each side gear in an axial direction in which the rotation axis extends, some of the plurality of friction plates are a plurality of case-side friction plates provided in the differential case, other of the plurality of friction plates are a plurality of gear-side friction plates provided in the side gears, the case-side friction plates and the gear-side friction plates are arranged side by side in the axial direction and slide relative to each other to generate the differential limiting torque, the case-side friction plates include a first case-side friction plate and a second case-side friction plate, the gear-side friction plates include a first gear-side friction plate and a second gear-side friction plate, and a first sliding diameter between the first case-side friction plate and the first gear-side friction plate and a second sliding diameter between the second case-side friction plate and the second gear-side friction plate are different from each other. The first sliding diameter between the first case-side friction plate and the first gear-side friction plate and the second sliding diameter between the second case-side friction plate and the second gear-side friction plate are made different from each other. When the first sliding diameter is smaller than the second sliding diameter, the differential limiting torque becomes smaller compared to that when the first sliding diameter is equal to the second sliding diameter. When the first sliding diameter is larger than the second sliding diameter, the differential limiting torque becomes larger compared to that when the first sliding diameter is equal to the second sliding diameter. Thus, the differential limiting torque for limiting the differential motion of the wheels of the vehicle can be adjusted by adjusting the first sliding diameter and the second sliding diameter. As described above, a vehicle differential device capable of adjusting the differential limiting torque with a simple configuration can be provided. In one embodiment, a first inner diameter of the first case-side friction plate and a second inner diameter of the second case-side friction plate are different from each other. The first sliding diameter and the second sliding diameter can be easily adjusted. In one embodiment, a first outer diameter of the first gear-side friction plate and a second outer diameter of the second gear-side friction plate are different from each other. The first sli