Differential device for vehicle and vehicle

Abstract

The invention provides a vehicle differential device and a vehicle which can adjust differential limiting torque with a simple structure. The rear differential device is provided with: a differential gear box that rotates by receiving the driving force of the rear drive motor; a pair of side gears coaxial with a rotating shaft of the differential gearbox; a pinion gear engaged with both of the pair of side gears; and a differential limiting mechanism that generates a differential limiting torque that limits the differential motion of the rear wheels of the vehicle. The differential restriction mechanism has a plurality of friction plates pressed in the axial direction by the side gears. Among the friction plates, a box-side friction plate is provided to the differential gear box, and a gear-side friction plate is provided to the side gear. The case-side friction plate and the gear-side friction plate are arranged side by side in the axial direction, and generate differential limiting torque by sliding relative to each other. A first sliding diameter of the first case-side friction plate and the first gear-side friction plate and a second sliding diameter of the second case-side friction plate and the second gear-side friction plate are different from each other.

Description

Technical Field

[0001] This invention relates to a differential device for vehicles and a vehicle. Background Technology

[0002] A vehicle differential device with a differential limiting mechanism is known. For example, the vehicle differential device disclosed in Patent Document 1 includes: a differential gearbox that is driven to rotate by the driving force of an engine; a differential gear mechanism that distributes the rotation of the differential gearbox to the wheel side via a pair of side gears; a conical clutch that is fastened and limits the differential movement of the differential gear mechanism by the meshing reaction force of the side gears formed between the differential gearbox and the clutch component; and a cam mechanism disposed between the clutch component and the side gears and pressed by the driving force.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 09-49560.

[0006] The technical problem that the invention aims to solve

[0007] When the differential limiting torque based on the differential limiting mechanism is large, the vehicle's straight-line stability improves, but the vehicle becomes difficult to turn. When the differential limiting torque based on the differential limiting mechanism is small, the vehicle becomes easy to turn, but the vehicle's straight-line stability decreases. In vehicle differential devices, in order to achieve a balance between the vehicle's straight-line stability and the ease of turning, it is desirable to adjust the differential limiting torque based on the differential limiting mechanism. Summary of the Invention

[0008] The present invention provides a differential device for vehicles that can adjust the differential limiting torque with a simple structure.

[0009] Technical means for solving technical problems

[0010] The vehicle differential device of the present invention is a vehicle differential device mounted on a vehicle, comprising: a differential gearbox that rotates under the driving force of a drive source; a pair of side gears disposed within the differential gearbox and coaxial with the rotation axis of the differential gearbox; a pinion disposed within the differential gearbox and meshing with both of the pair of side gears; and a differential limiting mechanism that generates a differential limiting torque for limiting the differential movement of the wheels of the vehicle, the differential limiting mechanism having a plurality of friction plates, which are pressed by the side gears along an axial direction extending from the rotation axis. A portion of the friction plates consists of multiple gearbox-side friction plates disposed on the differential gearbox, and another portion consists of multiple gear-side friction plates disposed on the side gears. The gearbox-side friction plates and the gear-side friction plates are arranged along the axial direction and generate the differential limiting torque by sliding against each other. The gearbox-side friction plates include a first gearbox-side friction plate and a second gearbox-side friction plate, and the gear-side friction plates include a first gear-side friction plate and a second gear-side friction plate. The first sliding diameter of the first gearbox-side friction plate and the first gear-side friction plate and the second sliding diameter of the second gearbox-side friction plate and the second gear-side friction plate are different from each other.

[0011] The first sliding diameter between the first gearbox-side friction plate and the first gear-side friction plate, and the second sliding diameter between the second gearbox-side friction plate and the second gear-side friction plate, are different from each other. When the first sliding diameter is smaller than the second sliding diameter, the differential limiting torque is smaller compared to the case where the first and second sliding diameters are equal. When the first sliding diameter is larger than the second sliding diameter, the differential limiting torque is larger compared to the case where the first and second sliding diameters are equal.

[0012] In this way, by adjusting the first sliding diameter and the second sliding diameter, the differential limiting torque used to limit the differential movement of the vehicle's wheels can be adjusted.

[0013] The above provides a vehicle differential device that can adjust the differential limiting torque with a simple structure.

[0014] In one embodiment, the first inner diameter of the first box-side friction plate and the second inner diameter of the second box-side friction plate are different from each other.

[0015] The first and second sliding diameters can be easily adjusted.

[0016] In one embodiment, the first outer diameter of the first gear-side friction plate and the second outer diameter of the second gear-side friction plate are different from each other.

[0017] The first and second sliding diameters can be easily adjusted.

[0018] In one embodiment, the differential limiting mechanism includes a first differential limiting mechanism and a second differential limiting mechanism. The first differential limiting mechanism is disposed on one side of the axial direction relative to the pinion, and the second differential limiting mechanism is disposed on the other side of the axial direction relative to the pinion. The first differential limiting mechanism has a first housing-side friction plate and a first gear-side friction plate, and a second housing-side friction plate and a second gear-side friction plate. In the first differential limiting mechanism, the first sliding diameter of the first housing-side friction plate and the first gear-side friction plate and the second sliding diameter of the second housing-side friction plate and the second gear-side friction plate are different from each other.

[0019] It can adjust the differential limiting torque on the wheel on the side corresponding to the first differential limiting mechanism.

[0020] In one embodiment, the differential limiting mechanism includes a first differential limiting mechanism and a second differential limiting mechanism. The first differential limiting mechanism is disposed on one side of the axial direction relative to the pinion, and the second differential limiting mechanism is disposed on the other side of the axial direction relative to the pinion. The first differential limiting mechanism has a first housing-side friction plate and a first gear-side friction plate, and the second differential limiting mechanism has a second housing-side friction plate and a second gear-side friction plate. The first sliding diameter of the first housing-side friction plate and the first gear-side friction plate in the first differential limiting mechanism and the second sliding diameter of the second housing-side friction plate and the second gear-side friction plate in the second differential limiting mechanism are different from each other.

[0021] It can make the differential limiting torque for the right wheel different from the differential limiting torque for the left wheel.

[0022] In one embodiment, the side gear has a gear body and a pressing body. The gear body meshes with the pinion, and the pressing body, together with the gear body, clamps a plurality of friction plates. The gear body and the pressing body are engaged with each other, and the gear side friction plates are disposed on the pressing body.

[0023] Multiple friction plates can be easily pressed using the gear body and the pressing body.

[0024] In one embodiment, the vehicle is rear-wheel drive or all-wheel drive, and the vehicle uses a differential device for differential control of the rear wheels of the vehicle.

[0025] Adjusting the differential limiting torque for the rear wheels can improve the vehicle's straight-line stability.

[0026] The vehicle according to the present invention includes: a front drive unit that rotates the front wheels; a rear drive unit that rotates the rear wheels independently of the front drive unit, and has a differential device for the vehicle.

[0027] A vehicle that improves straight-line stability by adjusting the differential limiting force on the rear wheels can be provided.

[0028] The effects of the invention

[0029] According to the present invention, a differential device for vehicles that can adjust the differential limiting torque with a simple structure can be provided. Attached Figure Description

[0030] Figure 1 The vehicle involved in the first embodiment is shown in a schematic diagram.

[0031] Figure 2 The diagram is shown as a cross-sectional view of the rear differential device according to the first embodiment, viewed along the front-rear direction.

[0032] Figure 3 The friction plate of the differential limiting mechanism according to the first embodiment is shown in an enlarged cross-sectional view of region III.

[0033] Figure 4 The box-side friction plate according to the first embodiment is shown in view IV.

[0034] Figure 5 The gear-side friction plate according to the first embodiment is shown in V-direction view.

[0035] Figure 6 The sliding path of the friction plates relative to each other in the first embodiment is shown in the conceptual diagram.

[0036] Figure 7 The sliding path of the friction plates relative to each other is shown in the conceptual diagram of the second embodiment.

[0037] Figure 8 The sliding path of the friction plates relative to each other is shown in the conceptual diagram of the third embodiment.

[0038] Figure 9 This refers to the rear differential device involved in the fourth embodiment.

[0039] Symbol Explanation

[0040] O Rotation axis

[0041] X-axis

[0042] T Differential limiting torque

[0043] dA first inner diameter

[0044] dB Second Inner Diameter

[0045] DA First outer diameter

[0046] DB Second Outer Diameter

[0047] EA First sliding path

[0048] EB Second Sliding Path

[0049] 1 vehicle

[0050] 2. Front wheels

[0051] 3. Rear wheel (wheel)

[0052] 10 Front drive units

[0053] 20 Rear Drive Unit

[0054] 21 Rear drive motor (drive source)

[0055] 30 Rear differential (vehicle differential)

[0056] 40 Differential Gearbox

[0057] 52 small gears

[0058] 60 side gears

[0059] 61 Gear Body

[0060] 62 Pressing Body

[0061] 70 Differential limiting mechanism

[0062] 71 First Differential Limiting Mechanism

[0063] 72 Second Differential Limiting Mechanism

[0064] 80 friction plate

[0065] 81 Box side friction plate

[0066] 81A First Box Side Friction Plate

[0067] 81B Second Box Side Friction Plate

[0068] 82 Gear Side Friction Plate

[0069] 82A First Gear Side Friction Plate

[0070] 82B Second gear side friction plate. Detailed Implementation

[0071] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications, or its uses.

[0072] In the following description, front, back, left, right, up, and down are based on the view observed from the occupants of vehicle 1.

[0073] <First Implementation Method>

[0074] The first embodiment will be described.

[0075] (vehicle)

[0076] Figure 1 Vehicle 1 is represented by a schematic diagram. In this example, vehicle 1 is an electric vehicle. Figure 1 As shown, vehicle 1 includes front wheels 2, rear wheels 3, a front drive unit 10, and a rear drive unit 20. Vehicle 1 is an all-wheel drive vehicle with dual-wheel rotation drive for both the front wheels 2 and the rear wheels 3. Vehicle 1 is capable of rotating the front wheels 2 and the rear wheels 3 independently.

[0077] A front drive unit 10 is disposed at the front of vehicle 1. A rear drive unit 20 is disposed at the rear of vehicle 1. The front drive unit 10 rotates the front wheels 2 independently of the rear drive unit 20. The rear drive unit 20 rotates the rear wheels 3 independently of the front drive unit 10. Vehicle 1 does not have a shaft (e.g., a driveshaft) that transmits driving force in the longitudinal direction.

[0078] The front drive unit 10 includes a front drive motor 11, a front reducer 12, and a front differential 13. The front drive motor 11 is the drive source for rotating the front wheels 2. The rotation of the front drive motor 11 is reduced by the front reducer 12 and then transmitted to the front differential 13. The front differential 13 is connected to the left and right front wheels 2 via a front drive shaft 14. The front differential 13 causes the left and right front wheels 2 to move differentially according to the driving state of the vehicle 1.

[0079] The rear drive unit 20 includes a rear drive motor 21, a rear reducer 22, and a rear differential 30. The arrangement of the rear drive unit 20 is symmetrical in the longitudinal direction relative to the arrangement of the front drive unit 10. The rear drive motor 21 is a drive source for rotating the rear wheels 3. The rear drive motor 21 is an example of a drive source. The rotation of the rear drive motor 21 is reduced in speed by the rear reducer 22 and then transmitted to the rear differential 30. The rear differential 30 is an example of a vehicle differential. The rear differential 30 is connected to the left and right rear wheels 3 via a rear drive shaft 24. The rear differential 30 causes the left and right rear wheels 3 to move differentially according to the driving state of the vehicle 1. The rear wheels 3 are an example of wheels.

[0080] In this embodiment, particular attention was paid to the rear differential device 30, so the rear differential device 30 will be described in detail below.

[0081] (Rear differential)

[0082] Figure 2 The diagram shows a cross-sectional view of the rear differential device 30 viewed in the front-rear direction. The rear differential device 30 is used for differential control of the left and right rear wheels 3 (wheels) of the vehicle 1. Figure 2 As shown, the rear differential 30 is mounted at the rear of the vehicle 1. The rear differential 30 includes a differential gearbox 40, a pinion shaft 51, a pair of pinions 52, a pair of side gears 60, and a differential limiting mechanism 70.

[0083] The differential gearbox 40 rotates under the driving force of the rear drive motor 21, which serves as the drive source. The driving force of the rear drive motor 21 is transmitted to the differential gearbox 40 of the rear differential device 30 via the rear reducer 22. The differential gearbox 40 rotates about the rotation axis O under the driving force of the rear reducer 22 via the final driven gear (not shown). The rotation axis O extends along the vehicle width direction (left-right direction).

[0084] In the following description, axis X represents the direction of extension of the rotation axis O. Axis X is the vehicle width direction (left-right direction). The side of the central axis C (described later) on axis X is called the inner side of axis X. The side of axis X opposite to the central axis C (described later) is called the outer side of axis X. Radial R represents the direction orthogonal to the rotation axis O. Radial R includes the vertical and horizontal directions. The side of rotation axis O on radial R is called the inner side of radial R. The side of radial R opposite to the rotation axis O is called the outer side of radial R.

[0085] The pinion shaft 51 is fixed inside the differential gearbox 40. The central axis C of the pinion shaft 51 extends radially R, orthogonal to the rotation axis O. The central axis C of the pinion shaft 51 extends radially R such that it crosses the rotation axis O. The rotation axis O passes through the central portion of the pinion shaft 51 along its length. When the differential gearbox 40 rotates about the rotation axis O, the pinion shaft 51 rotates together with the differential gearbox 40 around the rotation axis O. The pinion shaft 51 rotates about the rotation axis O with its central portion along its length as the center. The two ends of the pinion shaft 51 in the length direction revolve around the rotation axis O.

[0086] A pair (two) pinions 52 are disposed within the differential gearbox 40. The pinions 52 are mounted at both ends of the pinion shaft 51 along its length (radial R). One pinion 52 is mounted at one end of the pinion shaft 51. The other pinion 52 is mounted at the other end of the pinion shaft 51. The two pinions 52 are disposed on opposite sides of the radial R, separated from each other by a rotation axis O.

[0087] Pinion 52 is rotatable relative to pinion shaft 51 about the central axis C of pinion shaft 51. When the differential gearbox 40 rotates about the rotation axis O, pinion 52 rotates together with pinion shaft 51 about the rotation axis O. The radius of rotation of one pinion 52 relative to the rotation axis O is the same as the radius of rotation of the other pinion 52 relative to the rotation axis O.

[0088] The pinion 52 meshes with both sides of a pair of side gears 60, which will be described later. A washer 53 is disposed between the pinion 52 in the radial direction R and the differential gearbox 40.

[0089] A pair (two) side gears 60 are disposed within the differential gearbox 40. The side gears 60 are generally cylindrical. The cylindrical shaft of the side gear 60 is coaxial with the rotation axis O of the differential gearbox 40. The side gears 60 are disposed axially outside the pinion 52. One side gear 60 and the other side gear 60 are configured in mirror symmetry with respect to a plane passing through the central axis C and orthogonal to the rotation axis O.

[0090] A pair of side gears 60 mesh with a pinion 52. The pinion 52 meshes with both sides of the pair of side gears 60.

[0091] The side gear 60 is not fixed relative to the differential gearbox 40. The side gear 60 can rotate relative to the differential gearbox 40 about the rotation axis O.

[0092] The side gear 60 has a gear body 61 and a pressing body 62. The gear body 61 includes a gear portion 61a and a cylindrical portion 61b. The gear portion 61a of the gear body 61 in the side gear 60 meshes with a pinion 52. The cylindrical portion 61b extends from a portion radially R inside the gear portion 61a toward the opposite side (axially X outside) of the pinion 52.

[0093] The rear drive shaft 24 is fastened to the inner circumferential surface of the gear section 61a and the inner circumferential surface of the cylinder section 61b (see reference). Figure 1 An inner spline 64 (e.g., a spiral spline) is formed on the outer peripheral surface of the cylindrical portion 61b (see reference). Figure 3 ).

[0094] The pressing body 62 is positioned axially outward relative to the gear portion 61a of the gear body 61. The pressing body 62 is positioned radially outward relative to the cylinder portion 61b of the gear body 61. The pressing body 62 clamps a plurality of friction plates 80 in the differential limiting mechanism 70 described later and is positioned on the opposite side of the gear portion 61a of the gear body 61 in the axial direction X.

[0095] The pressing body 62 is generally cylindrical. The cylindrical shaft of the pressing body 62 is coaxial with the rotation shaft O of the differential gearbox 40. The pressing body 62 includes a pressing part 62a, an inner cylindrical part 62b, and an outer cylindrical part 62c. The pressing part 62a of the pressing body 62, together with the gear part 61a of the gear body 61, clamps multiple friction plates 80 along the axial direction X. The multiple friction plates 80 are pressed along the axial direction X by the pressing part 62a of the pressing body 62 and the gear part 61a of the gear body 61. The pressing part 62a is a circular plate with a central hole. The pressing part 62a contacts the outermost friction plate 80 located in the axial direction X. The radially outer portion R of the end face of the gear part 61a of the gear body 61, located in the axial direction X, contacts the innermost friction plate 80 located in the axial direction X. A partition 62d is disposed between the outer surface of the pressing part 62a in the axial direction X and the differential gearbox 40.

[0096] The inner cylindrical portion 62b extends from the radially inner side of the pressing portion 62a toward the axially inner side. A coil spring 62e is disposed between the axially inner end of the inner cylindrical portion 62b and the recessed portion of the radially inner side of the axially outer end face of the gear portion 61a of the gear body 61.

[0097] The outer cylindrical portion 62c extends from the radially inner side of the pressing portion 62a toward the axially outer side. The outer cylindrical portion 62c is received in a recess formed within the differential gearbox 40.

[0098] An outer spline 63 (e.g., a spiral spline) is formed on the inner circumferential surface of the pressing body 62 (see reference). Figure 3 As described above, an inner spline 64 (e.g., a helical spline) is formed on the outer peripheral surface of the cylindrical portion 61b of the gear body 61.

[0099] The gear body 61 and the pressing body 62 engage with each other. Specifically, the inner spline 64 on the outer circumferential surface of the cylindrical portion 61b of the gear body 61 and the outer spline 63 on the inner circumferential surface of the pressing body 62 are splined together. This restricts the rotation of the pressing body 62 relative to the gear body 61 about the rotation axis O. It allows the pressing body 62 to move axially X relative to the gear body 61.

[0100] (Friction plate of differential limiting mechanism)

[0101] Figure 3 The friction plate 80 of the differential limiting mechanism 70 is shown in an enlarged cross-sectional view of region III. Figure 4 The box-side friction plate 81, described later, is shown in view of direction IV. Figure 5 The gear-side friction plate 82, described later, is shown in V-direction.

[0102] like Figure 3As shown, the differential limiting mechanism 70 generates a differential limiting torque T for limiting the differential movement of the left and right rear wheels 3 (wheels) of vehicle 1. The differential limiting mechanism 70 has multiple friction plates 80. The friction plates 80 are plate-shaped with the thickness direction along the axial direction X. Viewed from the axial direction X, the friction plates 80 are annular with a central hole. The axis of the friction plates 80 is coaxial with the rotation axis O of the differential gearbox 40. The multiple friction plates 80 are arranged along the axial direction X.

[0103] Multiple friction plates 80 are pressed along the axial direction X by a side gear 60. The multiple friction plates 80 are arranged axially X between the gear portion 61a of the gear body 61 and the pressing portion 62a of the pressing body 62. The multiple friction plates 80 are clamped along the axial direction X by the gear portion 61a of the gear body 61 and the pressing portion 62a of the pressing body 62, and are pressed along the axial direction X.

[0104] A portion of the multiple friction plates 80 consists of multiple box-side friction plates 81. Another portion (the remaining portion) of the multiple friction plates 80 consists of multiple gear-side friction plates 82.

[0105] like Figure 3 and Figure 4 As shown, a side friction plate 81 is provided on the differential gearbox 40. A cylindrical wall portion 41 is formed in the differential gearbox 40. The cylindrical wall portion 41 is circular when viewed from the axial direction X. The cylindrical wall portion 41 extends along the axial direction X. A plurality of grooves 41b are provided on the inner circumferential surface 41a of the cylindrical wall portion 41, which are recessed radially outward. The grooves 41b extend along the axial direction X. The plurality of grooves 41b are arranged around the rotation axis O.

[0106] Multiple protrusions 81b protruding radially outward are provided on the outer peripheral surface 81a of the box-side friction plate 81. The outer peripheral surface 81a of the box-side friction plate 81 faces the inner peripheral surface 41a of the cylinder wall portion 41. The protrusions 81b of the box-side friction plate 81 are engaged with the grooves 41b of the cylinder wall portion 41.

[0107] The rotation of the gearbox-side friction plate 81 relative to the cylinder wall portion 41 of the differential gearbox 40 about the rotation axis O is restricted. Movement of the gearbox-side friction plate 81 relative to the cylinder wall portion 41 of the differential gearbox 40 along the axial direction X is permitted.

[0108] like Figure 3 and Figure 5 As shown, a gear-side friction plate 82 is disposed on a side gear 60. Specifically, the gear-side friction plate 82 is disposed on a pressing body 62 of the side gear 60. A plurality of grooves 62g are provided on the outer peripheral surface 62f of the inner cylindrical portion 62b of the pressing body 62 in the side gear 60, recessed radially inward (R). The grooves 62g extend along the axial direction (X). The plurality of grooves 62g are arranged around the rotation axis O.

[0109] The gear-side friction plate 82 has a plurality of protrusions 82b that protrude radially inward on its inner circumferential surface 82a. The inner circumferential surface 82a of the gear-side friction plate 82 faces the outer circumferential surface 62f of the inner cylindrical portion 62b of the pressing body 62. The protrusions 82b of the gear-side friction plate 82 are engaged with the grooves 62g of the inner cylindrical portion 62b of the pressing body 62.

[0110] The rotation of the gear-side friction plate 82 relative to the pressing body 62 of the side gear 60 about the rotation axis O is restricted. Movement of the gear-side friction plate 82 relative to the pressing body 62 of the side gear 60 along the axial direction X is permitted.

[0111] The inner diameter of the gearbox-side friction plate 81 is smaller than the outer diameter of the gear-side friction plate 82. The outer diameter of the gear-side friction plate 82 is larger than the inner diameter of the gearbox-side friction plate 81. The inner radial portion (R) of the gearbox-side friction plate 81 and the outer radial portion (R) of the gear-side friction plate 82 slide relative to each other about the rotation axis O. Alternatively, the outer diameters of the gearbox-side friction plate 81 and the gear-side friction plate 82 can be the same, and their inner diameters can also be the same.

[0112] like Figure 3 As shown, the specific friction plate 80a (in this example, a gear-side friction plate 82) closest to the innermost side in the axial direction X of the friction plates 80 is thicker than the other friction plates 80. The specific friction plate 80a contacts the gear portion 61a of the gear body 61 and the disc spring 62e. The other friction plates 80, besides the specific friction plate 80a, have the same thickness.

[0113] The gearbox-side friction plate 81 and the gear-side friction plate 82 are arranged alternately along the axial direction X. The gearbox-side friction plate 81 and the gear-side friction plate 82 generate a differential limiting torque T by sliding relative to each other about the rotation axis O (see reference). Figure 4 and Figure 5 The differential limiting torque T is described below.

[0114] Return to Figure 2 The differential limiting mechanism 70 includes a first differential limiting mechanism 71 and a second differential limiting mechanism 72. The first differential limiting mechanism 71 corresponds to the right rear wheel 3 (wheel). The second differential limiting mechanism 72 corresponds to the left rear wheel 3 (wheel). The first differential limiting mechanism 71 is located on the side of the axial direction X relative to the pinion 52. Figure 2 (On the right side). The second differential limiting mechanism 72 is located on the opposite side of the pinion 52 in the axial direction X. Figure 2 (Left side).

[0115] In this example, the first differential limiting mechanism 71 and the second differential limiting mechanism 72 are configured in mirror symmetry with respect to a plane passing through the central axis C and orthogonal to the rotation axis O.

[0116] (The sliding radius of the friction plates)

[0117] Figure 6 The sliding radius of the friction plates 80 relative to each other is shown in a conceptual diagram. Furthermore, for ease of understanding, the thickness of a particular friction plate 80a is made the same as the thickness of the other friction plates 80. Additionally, for ease of understanding, with... Figure 3 In comparison, the inner and outer diameters of the gearbox-side friction plate 81 are shown as larger, while the inner and outer diameters of the gear-side friction plate 82 are shown as smaller. The gearbox-side friction plate 81 includes a first gearbox-side friction plate 81A and a second gearbox-side friction plate 81B. The gear-side friction plate 82 includes a first gear-side friction plate 82A and a second gear-side friction plate 82B.

[0118] In this example, there are eight friction plates 80 (including a specific friction plate 80a). There are four box-side friction plates 81 and four gear-side friction plates 82. Of the four box-side friction plates 81, there is one first box-side friction plate 81A and three second box-side friction plates 81B. Of the four gear-side friction plates 82, there is one first gear-side friction plate 82A and three second gear-side friction plates 82B.

[0119] The first box-side friction plate 81A and the first gear-side friction plate 82A are adjacent to each other in the axial direction X. The first box-side friction plate 81A and the first gear-side friction plate 82A slide relative to each other on the first sliding surface 83A about the rotation axis O. The second box-side friction plate 81B and the second gear-side friction plate 82B are adjacent to each other in the axial direction X. The second box-side friction plate 81B and the second gear-side friction plate 82B slide relative to each other on the second sliding surface 83B about the rotation axis O.

[0120] As described above, viewed along the axial direction X, the friction plate 80 is an annular shape with a central hole. The first gearbox-side friction plate 81A has a first inner diameter dA. The second gearbox-side friction plate 81B has a second inner diameter dB. The first gear-side friction plate 82A has a first outer diameter DA. The second gear-side friction plate 82B has a second outer diameter DB. Furthermore, the inner and outer diameters, with the rotation axis O as a reference, can be defined using either a diameter or a radius.

[0121] The first inner diameter dA of the first box-side friction plate 81A and the second inner diameter dB of the second box-side friction plate 81B are different. In this example, the first inner diameter dA of the first box-side friction plate 81A is smaller than the second inner diameter dB of the second box-side friction plate 81B.

[0122] The first outer diameter DA of the first gear-side friction plate 82A and the second outer diameter DB of the second gear-side friction plate 82B are the same.

[0123] The first sliding diameter EA of the first gear side friction plate 81A and the first gear side friction plate 82A, and the second sliding diameter EB of the second gear side friction plate 81B and the second gear side friction plate 82B are different from each other. The first sliding diameter EA is smaller than the second sliding diameter EB.

[0124] The first sliding diameter EA corresponds to the center position of the radial direction R in the first sliding surface 83A. The first sliding diameter EA corresponds to the center between the inner end and the outer end of the radial direction R in the first sliding surface 83A. The first sliding diameter EA is the center value of the first inner diameter dA and the first outer diameter DA.

[0125] The second sliding diameter EB corresponds to the center position of the radial direction R in the second sliding surface 83B. The second sliding diameter EB corresponds to the center between the inner and outer ends of the radial direction R in the second sliding surface 83B. The second sliding diameter EB is the center value of the second inner diameter dB and the second outer diameter DB.

[0126] The first sliding diameter EA and the second sliding diameter EB are respectively referred to as the effective sliding diameters.

[0127] Here, the differential limiting torque T acts in the circumferential direction about the rotation axis O (refer to...). Figure 4 and Figure 5 The differential limiting torque T is obtained by multiplying the frictional force acting on the sliding surfaces (first sliding surface 83A, second sliding surface 83B) between the gear-side friction plate 81 (first gear-side friction plate 81A, second gear-side friction plate 81B) and the gear-side friction plate 82 (first gear-side friction plate 82A, second gear-side friction plate 82B), the number of such sliding surfaces, and the sliding diameters (first sliding diameter EA, second sliding diameter EB).

[0128] If the sliding diameter is decreased (first sliding diameter EA, second sliding diameter EB), the differential limiting torque T decreases. If the sliding diameter is increased (first sliding diameter EA, second sliding diameter EB), the differential limiting torque T increases.

[0129] In this example, since the first sliding diameter EA is smaller than the second sliding diameter EB, the differential limiting torque T is smaller compared to the case where the first sliding diameter EA and the second sliding diameter EB are equal. Furthermore, assuming the first sliding diameter EA is larger than the second sliding diameter EB, the differential limiting torque T becomes larger compared to the case where the first sliding diameter EA and the second sliding diameter EB are equal.

[0130] In this example, the first differential limiting mechanism 71 and the second differential limiting mechanism 72 in the differential limiting mechanism 70 have the same structure. The first differential limiting mechanism 71 has a first gearbox-side friction plate 81A and a first gear-side friction plate 82A, and a second gearbox-side friction plate 81B and a second gear-side friction plate 82B. The second differential limiting mechanism 72 has a first gearbox-side friction plate 81A and a first gear-side friction plate 82A, and a second gearbox-side friction plate 81B and a second gear-side friction plate 82B.

[0131] In the first differential limiting mechanism 71, the first sliding diameter EA of the first gear-side friction plate 81A and the first gear-side friction plate 82A, and the second sliding diameter EB of the second gear-side friction plate 81B and the second gear-side friction plate 82B are different from each other. In the second differential limiting mechanism 72, the first sliding diameter EA of the first gear-side friction plate 81A and the first gear-side friction plate 82A, and the second sliding diameter EB of the second gear-side friction plate 81B and the second gear-side friction plate 82B are different from each other.

[0132] (Effects)

[0133] In the rear differential device 30, the first sliding diameter EA of the first gear side friction plate 81A and the first gear side friction plate 82A, and the second sliding diameter EB of the second gear side friction plate 81B and the second gear side friction plate 82B are different from each other. When the first sliding diameter EA is smaller than the second sliding diameter EB, the differential limiting torque T is smaller compared to the case where the first sliding diameter EA and the second sliding diameter EB are equal. When the first sliding diameter EA is larger than the second sliding diameter EB, the differential limiting torque T is larger compared to the case where the first sliding diameter EA and the second sliding diameter EB are equal.

[0134] Thus, in the rear differential device 30, by adjusting the first sliding diameter EA and the second sliding diameter EB, the differential limiting torque T used to limit the differential movement of the rear wheel 3 (wheel) of the vehicle 1 can be adjusted.

[0135] The above provides a rear differential device 30 that can adjust the differential limiting torque T with a simple structure.

[0136] By adjusting the differential limiting torque T on the rear wheel 3 (wheel) of vehicle 1 through the rear differential device 30, the balance between the straight-line stability and the turning ease of vehicle 1 can be adjusted.

[0137] Since the first sliding diameter EA and the second sliding diameter EB can be changed, the number of different types of parts in the rear differential device 30 can be suppressed.

[0138] The first inner diameter dA of the first box-side friction plate 81A and the second inner diameter dB of the second box-side friction plate 81B are different. The first sliding diameter EA and the second sliding diameter EB can be easily adjusted.

[0139] The differential limiting torque T for the right rear wheel 3 on the side corresponding to the first differential limiting mechanism 71 can be adjusted. Similarly, the differential limiting torque T for the left rear wheel 3 on the side corresponding to the second differential limiting mechanism 72 can be adjusted.

[0140] The side gear 60 has a gear body 61 that meshes with the pinion 52 and a pressing body 62 that clamps a plurality of friction plates 80 together with the gear body 61. The plurality of friction plates 80 can be easily pressed by means of the gear body 61 and the pressing body 62.

[0141] Vehicle 1 is an all-wheel drive vehicle, and the rear differential device 30 is used for differential control of the rear wheels 3. By adjusting the differential limiting torque T on the rear wheels 3, the straight-line stability of vehicle 1 can be improved.

[0142] The vehicle 1 includes a front drive unit 10 that rotates the front wheels 2 and a rear drive unit 20 that rotates the rear wheels 3 independently of the front drive unit 10 and has a rear differential device 30. This provides a vehicle 1 that improves straight-line stability by adjusting the differential limiting torque T on the rear wheels 3.

[0143] <Second Implementation Method>

[0144] The second embodiment will be described. In the following description, the same symbols are used for structures that are the same as those in the above embodiment, and detailed descriptions are omitted. Figure 7 The sliding radius of the friction plates 80 is shown in the conceptual diagram.

[0145] The first inner diameter dA of the first gearbox-side friction plate 81A and the second inner diameter dB of the second gearbox-side friction plate 81B are the same. The first outer diameter DA of the first gear-side friction plate 82A and the second outer diameter DB of the second gear-side friction plate 82B are different. In this example, the first outer diameter DA of the first gear-side friction plate 82A is larger than the second outer diameter DB of the second gear-side friction plate 82B.

[0146] The first sliding diameter EA of the first gear side friction plate 81A and the first gear side friction plate 82A, and the second sliding diameter EB of the second gear side friction plate 81B and the second gear side friction plate 82B are different from each other. The first sliding diameter EA is larger than the second sliding diameter EB.

[0147] The other structures are the same as those described in the above embodiments.

[0148] The first sliding diameter EA and the second sliding diameter EB can be easily adjusted.

[0149] <Third Implementation Method>

[0150] The third embodiment will be described. In the following description, the same symbols are used for structures that are the same as those in the embodiments described above, and detailed descriptions are omitted. Figure 8 The sliding radius of the friction plates 80 is shown in the conceptual diagram.

[0151] The first differential limiting mechanism 71 and the second differential limiting mechanism 72 in the differential limiting mechanism 70 have different structures.

[0152] The first differential limiting mechanism 71 has a first gearbox-side friction plate 81A and a first gear-side friction plate 82A. The second differential limiting mechanism 72 has a second gearbox-side friction plate 81B and a second gear-side friction plate 82B.

[0153] The first sliding diameter EA of the first box-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 of the second box-side friction plate 81B and the second gear-side friction plate 82B in the second differential limiting mechanism 72 are different from each other.

[0154] In this example, the first inner diameter dA of the first gearbox-side friction plate 81A is smaller than the second inner diameter dB of the second gearbox-side friction plate 81B. Furthermore, the first outer diameter DA of the first gear-side friction plate 82A is smaller than the second outer diameter DB of the second gear-side friction plate 82B. The first sliding diameter EA is smaller than the second sliding diameter EB.

[0155] The other structures are the same as those described in the above embodiments.

[0156] The differential limiting torque T for the right rear wheel 3 (wheel) corresponding to the first differential limiting mechanism 71 and the differential limiting torque T for the left rear wheel 3 (wheel) corresponding to the second differential limiting mechanism 72 can be different from each other.

[0157] <Fourth Implementation Method>

[0158] The fourth embodiment will be described. In the following description, the same symbols are used for structures that are the same as those in the embodiments described above, and detailed descriptions are omitted. Figure 9 This indicates the rear differential device 30.

[0159] The side gear 60 has a gear body 61. The side gear 60 does not have a pressing body 62. A plurality of friction plates 80 are clamped and pressed along the axial direction X by means of the gear portion 61a of the gear body 61 and the wall portion of the differential gearbox 40. The gear side friction plate 82 is provided on the outer peripheral surface of the cylindrical portion 61b of the gear body 61 in the side gear 60. Specifically, the protrusion 82b of the gear side friction plate 82 is fitted into a groove provided on the outer peripheral surface of the cylindrical portion 61b of the gear body 61 (extending along the axial direction X and arranged around the rotation axis O).

[0160] The other structures are the same as those described in the above embodiments.

[0161] <Other Implementation Methods>

[0162] The present invention has been described above through preferred embodiments, but such description is not a limitation and various changes, substitutions or combinations are of course possible.

[0163] The first inner diameter dA of the first gearbox side friction plate 81A can also be larger than the second inner diameter dB of the second gearbox side friction plate 81B. The first outer diameter DA of the first gear side friction plate 82A can also be smaller than the second outer diameter DB of the second gear side friction plate 82B.

[0164] The differential limiting mechanism 70 can also be provided on either one side or the other side of the axial direction X, compared to the pinion 52.

[0165] In the above embodiments, the differential limiting mechanism 70 is only provided on the rear differential device 30, but it is not limited to this. It can also be provided on both the rear differential device 30 and the front differential device 13, or it can be provided only on the front differential device 13.

[0166] Alternatively, comb teeth can be used instead of the grooves used to hold the friction plate 80. The friction plate 80 may also have a different structure than the grooves and comb teeth, and be disposed in the differential gearbox 40 or the side gear 60.

[0167] In the above embodiment, the rear differential device 30 with differential limiting mechanism 70 is used for differential control of the left and right rear wheels 3 (wheels) of the vehicle 1, but is not limited thereto. Alternatively, the front differential device 13 with differential limiting mechanism 70 can be used for differential control of the left and right front wheels 2 (wheels) of the vehicle 1.

[0168] Vehicle 1 can also be a rear-wheel drive vehicle with the rear wheels 3 rotating and driven by rotation. Vehicle 1 can also be a front-wheel drive vehicle with the front wheels 2 rotating and driven by rotation. In these cases, the rear differential 30 and the front differential 13 can also be connected via a driveshaft.

[0169] Vehicle 1 can also be driven by an engine. In this case, the differential gearbox 40 rotates under the driving force of the engine, which is the driving source.

[0170] Industrial utilization potential

[0171] Since this invention is applied to differential devices for vehicles and vehicles, it is very useful and has high potential for industrial application.

Claims

1. A differential device for a vehicle, mounted on a vehicle, characterized in that, have: A differential gearbox that rotates under the driving force of a drive source; A pair of side gears, which are disposed within the differential gearbox and coaxial with the rotational shaft of the differential gearbox; A pinion gear, disposed within the differential gearbox and meshing with both sides of the pair of side gears; and A differential limiting mechanism that generates a differential limiting torque for limiting the differential movement of the vehicle's wheels. The differential limiting mechanism has multiple friction plates, which are pressed axially by the side gear extending along the rotation axis. A portion of the plurality of friction plates are multiple box-side friction plates disposed on the differential gearbox. Another part of the plurality of friction plates consists of a plurality of gear-side friction plates disposed on the side gear. The gearbox-side friction plate and the gear-side friction plate are arranged along the axial direction and generate the differential limiting torque by sliding against each other. The box-side friction plate includes a first box-side friction plate and a second box-side friction plate. The gear-side friction plate includes a first gear-side friction plate and a second gear-side friction plate. The first sliding diameter of the first box-side friction plate and the first gear-side friction plate and the second sliding diameter of the second box-side friction plate and the second gear-side friction plate are different from each other.

2. The differential device for vehicles according to claim 1, characterized in that, The first inner diameter of the first box-side friction plate and the second inner diameter of the second box-side friction plate are different from each other.

3. The differential device for vehicles according to claim 1, characterized in that, The first outer diameter of the first gear-side friction plate and the second outer diameter of the second gear-side friction plate are different from each other.

4. The vehicle differential device according to any one of claims 1 to 3, characterized in that, The differential limiting mechanism includes a first differential limiting mechanism and a second differential limiting mechanism. The first differential limiting mechanism is disposed on one side of the axial direction relative to the pinion, and the second differential limiting mechanism is disposed on the other side of the axial direction relative to the pinion. The first differential limiting mechanism includes a first gearbox-side friction plate and a first gear-side friction plate, and a second gearbox-side friction plate and a second gear-side friction plate. In the first differential limiting mechanism, the first sliding diameter of the first box-side friction plate and the first gear-side friction plate and the second sliding diameter of the second box-side friction plate and the second gear-side friction plate are different from each other.

5. The vehicle differential device according to any one of claims 1 to 3, characterized in that, The differential limiting mechanism includes a first differential limiting mechanism and a second differential limiting mechanism. The first differential limiting mechanism is disposed on one side of the axial direction relative to the pinion, and the second differential limiting mechanism is disposed on the other side of the axial direction relative to the pinion. The first differential limiting mechanism has a first gearbox-side friction plate and a first gear-side friction plate. The second differential limiting mechanism has a second gearbox-side friction plate and a second gear-side friction plate. The first sliding diameter of the first gear side friction plate and the first gear side friction plate in the first differential limiting mechanism and the second sliding diameter of the second gear side friction plate and the second gear side friction plate in the second differential limiting mechanism are different from each other.

6. The vehicle differential device according to any one of claims 1 to 3, characterized in that, The side gear has a gear body and a pressing body. The gear body meshes with the pinion, and the pressing body, together with the gear body, clamps a plurality of friction plates. The gear body and the pressing body engage with each other. The gear-side friction plate is disposed on the pressing body.

7. The vehicle differential device according to any one of claims 1 to 3, characterized in that, The vehicle is either rear-wheel drive or all-wheel drive. The vehicle differential device is used for differential control of the rear wheels of the vehicle.

8. A vehicle, characterized in that, have: A front drive unit that rotates the front wheels; A rear drive unit that rotates the rear wheels independently of the front drive unit, and has the vehicle differential device as described in claim 7.

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