Differential device

Abstract

To provide a differential device capable of stabilizing differential limiting characteristics of a differential limiting part.SOLUTION: A differential device 1 includes a differential case 7, a pinion gear 11, a pair of side gears 13, 15, a pair of differential limiting parts 5, 5, a pair of energizing members 43, 43 for imparting a preload to the pair of differential limiting parts 5, 5 respectively, and a thrust block 45 receiving a load from the pair of energizing members 43, 43 applied to the pair of side gears 13, 15. The pair of side gears 13, 15 includes a gear member 29, and an operation member 31, respectively. The energizing member 43 is arranged between the gear member 29 and the operation member 31, and the load to move the gear member 29 toward the inside in the axial direction of the side gears 13, 15 is applied to the gear member 29. The thrust block 45 is arranged between the pair of gear members 29, 29 so as to come into contact with the pair of gear members 29, 29 and to be movable in the axial direction of the side gears 13, 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, a differential device includes a rotatable differential case, a pinion gear rotatably supported within the differential case and revolving with the rotation of the differential case, and a pair of side gears that mesh with the pinion gear and rotate relatively. The differential device also includes a pair of differential limiting sections that are respectively provided between the differential case and the pair of side gears to limit the differential between the pair of side gears, and a pair of biasing members that apply a preload to each of the pair of differential limiting sections. A known differential device also includes thrust blocks that receive the load from the pair of biasing members that is applied to the pair of side gears (see Patent Document 1).

[0003] In this differential, the pair of side gears each have a gear member that meshes with the pinion gear, and an actuating member that is rotatable integrally with the gear member and axially movable and actuates the differential limiting unit. The biasing member is disposed between the gear member and the actuating member and applies a load to the gear member that moves the gear member axially inward of the side gear. The thrust block is disposed between the pair of gear members and in contact with the pair of gear members and receives the load from the pair of biasing members that is applied to the pair of gear members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-191961 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a differential device such as that described in Patent Document 1, the biasing forces of the pair of biasing members may differ due to individual differences caused by manufacturing tolerances, assembly errors, etc. If the biasing forces of the pair of biasing members differ, the preloads applied to the pair of differential limiting portions will differ, and the differential limiting characteristics of the differential limiting portions may become unstable.

[0006] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a differential device that can stabilize the differential limiting characteristics of the differential limiting section. [Means for solving the problem]

[0007] The differential device according to this embodiment includes a rotatably arranged differential case, a pinion gear supported rotatably within the differential case and revolving with the rotation of the differential case, a pair of side gears meshing with the pinion gear and relatively rotatable, a pair of differential limiting sections respectively provided between the differential case and the pair of side gears to limit the differential between the pair of side gears, a pair of biasing members each applying a preload to the pair of differential limiting sections, and a pair of biasing members each receiving a load from the pair of biasing members applied to the pair of side gears. and a thrust block, wherein the pair of side gears each have a gear member that meshes with the pinion gear, and an operating member that is rotatable integrally with the gear member, is arranged to be movable axially, and operates the differential limiting unit, the biasing member is arranged between the gear member and the operating member, and applies a load to the gear member that moves the gear member toward the axial inside of the side gear, and the thrust block is arranged between the pair of gear members, abuts against the pair of gear members, and is movable in the axial direction of the side gear. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a differential device that can stabilize the differential limiting characteristics of the differential limiting section. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view of the differential device according to the embodiment. [Figure 2] FIG. 2 is a schematic diagram of a pinion shaft and a thrust block of the differential device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The differential device according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0011] 1, a differential device 1 according to this embodiment is disposed between a drive source (not shown), such as an engine or an electric motor, and left and right wheels (not shown). Driving force from the drive source is transmitted to the differential device 1 via a transmission (not shown), and the driving force is distributed to the left and right wheels via a pair of output shafts (not shown).

[0012] As shown in FIGS. 1 and 2, the differential device 1 includes a differential mechanism 3 and a differential limiting unit 5.

[0013] The differential mechanism 3 includes a differential case 7, a pinion shaft 9, a pinion gear 11, and a pair of side gears 13 and 15. As an example, in this embodiment, a bevel gear pair is used for the meshing combination between the pinion gear 11 and the pair of side gears 13 and 15, but a face gear pair may also be used.

[0014] The differential case 7 has a divided structure including, for example, a case main body 17 and a cover body 19. The case main body 17 has an opening on one side in the axial direction, which mainly forms the internal space of the differential case 7. The cover body 19 is placed on the case main body 17 so as to close the opening of the case main body 17 after accommodating various components inside through the opening of the case main body 17, and is fixed integrally with the case main body 17 via fixing members (not shown) such as a plurality of bolts.

[0015] The differential case 7 is rotatably supported by a stationary member (not shown) such as a carrier via bearings (not shown) at the outer peripheries of bosses 21 and 23 formed on both axial sides. A flange 25 to which a ring gear (not shown) is fixed is formed on the differential case 7. The ring gear fixed to the flange 25 meshes with a power transmission gear (not shown) that transmits driving force, and the driving force is transmitted to rotate the differential case 7. A pinion shaft 9, a pinion gear 11, a pair of side gears 13 and 15, etc. are housed and arranged within the differential case 7.

[0016] The pinion shaft 9 has an end that engages with a hole formed in the differential case 7 and is prevented from coming off and rotating by a pin 27, and is rotatably driven integrally with the differential case 7. Note that the pinion shaft 9 is configured as a single long pinion shaft 9, but is not limited to this, and may be configured as a single long pinion shaft 9 and two short pinion shafts 9. In this case, a hole is provided in the center of the long pinion shaft 9, and the ends of the two short pinion shafts 9 are engaged with the hole, and the pinion shaft 9 is rotatably driven integrally with the differential case 7. Pinion gears 11 are supported on both axial ends of the pinion shaft 9, respectively.

[0017] A plurality of pinion gears 11 (two in this example) are arranged at equal intervals around the circumferential direction of the differential case 7, and each is supported on the shaft end side of the pinion shaft 9 and revolves with the rotation of the differential case 7. The pinion gear 11 transmits driving force to the pair of side gears 13, 15, and is rotatably supported on the pinion shaft 9 so as to be rotationally driven when a differential rotation occurs between the pair of meshed side gears 13, 15.

[0018] The pair of side gears 13, 15 are housed in the differential case 7 so as to be capable of relative rotation. Each of the pair of side gears 13, 15 includes a gear member 29 and an operating member 31. In the pair of side gears 13, 15, the gear member 29 and the operating member 31 are formed symmetrically on the left and right, so the following mainly describes only one of them, and a description of the other is omitted.

[0019] The gear member 29 is formed in an annular shape, and has a gear portion formed on its outer periphery that meshes with the pinion gear 11. The gear member 29 meshes with the pinion gear 11, thereby transmitting driving force from the pinion gear 11 to the pair of side gears 13, 15. In addition, when differential rotation occurs between the pair of side gears 13, 15, the gear member 29 rotates the pinion gear 11.

[0020] The actuating member 31 is formed in a concave annular shape capable of accommodating a portion of the gear member 29 in the axial direction so that it can be disposed axially adjacent to the gear member 29. A sliding surface 33 that is conically inclined in the axial direction is provided on a portion of the actuating member 31 that is positioned radially outward of the gear member 29. On the inner circumferential side of the actuating member 31, spline-shaped output portions 35, 37 are formed in the pair of side gears 13, 15 so as to be integrally rotatable with the pair of output shafts. The actuating member 31 outputs the driving force input from the differential case 7 to the pair of side gears 13, 15 to the left and right wheels via the pair of output shafts.

[0021] A cam portion 39 that converts rotational torque into axial thrust force is provided between the gear member 29 and the operating member 31. The cam portion 39 is made up of a plurality of engaging recesses provided on the inner circumferential side of the gear member 29 and a plurality of engaging protrusions that are provided on the outer circumferential side of the operating member 31 and can engage with the plurality of engaging recesses. The cam portion 39 enables the gear member 29 and the operating member 31 to rotate integrally by engaging the plurality of engaging recesses with the plurality of engaging protrusions.

[0022] On the other hand, in cam portion 39, the engagement surface in the rotational direction between the multiple engagement recesses and the multiple engagement protrusions is a cam surface inclined by a predetermined angle. When a driving force (driving torque) is input to differential case 7, the cam surface of cam portion 39 is actuated by the driving force branched from pinion gear 11 and input to the pair of side gears 13, 15, causing cam portion 39 to move operating member 31 axially outward. The axial movement of operating member 31 by cam portion 39 can increase and strengthen the differential limiting force of the pair of differential limiting units 5, 5 arranged between differential case 7 and the pair of side gears 13, 15.

[0023] The pair of differential limiting units 5, 5 are disposed between the differential case 7 and the pair of side gears 13, 15. The pair of differential limiting units 5, 5 are formed symmetrically, so the following mainly describes one of them, and the other is omitted. The differential limiting unit 5 has a tapered ring 41 and an operating member 31 that slide against each other.

[0024] The tapered rings 41 are disposed on the differential case 7 at positions corresponding to the sliding surfaces 33 of the operating members 31 of the pair of side gears 13, 15. The tapered rings 41 rotate integrally with the differential case 7 by engaging multiple convex portions formed in the circumferential direction on the inner peripheral side with concave portions formed on the inner wall surface of the differential case 7.

[0025] The tapered ring 41 slides on the sliding surfaces 33 of the operating members 31 of the pair of side gears 13, 15, which are moved axially by the meshing reaction force with the pinion gear 11 in accordance with the magnitude of the driving force (driving torque) input to the differential case 7. At this time, the sliding friction between the tapered ring 41 and the sliding surfaces 33, which is the differential limiting force of the differential limiting unit 5, is increased and strengthened by the cam thrust force of the cam unit 39.

[0026] The differential limiting unit 5 transmits friction torque between the differential case 7 and the pair of side gears 13, 15 in response to the magnitude of the cam thrust force, thereby limiting the differential movement of the differential mechanism 3. The differential limiting unit 5 is a cone clutch type torque-sensitive friction clutch. A preload is applied to the differential limiting unit 5 by a biasing member 43.

[0027] The biasing member 43 is made of, for example, a disc spring, and is arranged axially between the gear member 29 and the operating member 31. The biasing member 43 biases the gear member 29 axially inward (toward the pinion gear 11) and biases the operating member 31 axially outward (toward the limited differential unit 5). By arranging the biasing member 43 between the gear member 29 and the operating member 31, a preload is applied to the limited differential unit 5, making it possible to stabilize the limited differential characteristic (intermittent characteristic) of the limited differential unit 5. Meanwhile, the axially inward load applied to the gear member 29 from the biasing member 43 is input to the thrust block 45.

[0028] The thrust block 45 is disposed axially between the pair of side gears 13, 15 and is formed in a cylindrical shape that follows the axial direction of the side gears 13, 15. The axial ends of the pair of actuating members 31 are inserted into both axial ends of the side gears 13, 15, and the thrust block 45 is supported radially by the pair of actuating members 31, 31. The axial end faces of the pair of gear members 29, 29 abut against the axial end faces of the thrust block 45 on both axial sides of the side gears 13, 15. Due to the abutment with the pair of gear members 29, 29, the axially inward load applied to the pair of gear members 29, 29 from the pair of biasing members 43, 43 is input to the thrust block 45.

[0029] Two circular holes 47, through which the pinion shaft 9 is inserted, are formed in the thrust block 45. The inner diameter D1 of the holes 47 is set larger than the outer diameter D2 of the pinion shaft 9. Therefore, a gap C is formed between the thrust block 45 and the pinion shaft 9 in the axial direction of the side gears 13, 15. The provision of the gap C allows the thrust block 45 to move in the axial direction of the side gears 13, 15. The circular holes 47 may be elongated holes. Alternatively, the hole 47 may have a long portion that combines the gap C, through which the thrust block 45 can move axially, with a length equal to the diameter of the pinion shaft 9, and a short portion that allows the pinion shaft 9 to be assembled.

[0030] Axial movement of the thrust block 45 occurs when there is a difference in the preload applied by the pair of biasing members 43 to the pair of differential limiting units 5. For example, because the pair of biasing members 43 are separate, the biasing forces may differ due to individual differences caused by manufacturing tolerances or assembly errors. If there is a difference in the biasing forces of the pair of biasing members 43, the preloads applied to the pair of differential limiting units 5 will differ, and the differential limiting characteristics (intermittent characteristics) of the pair of differential limiting units 5 will become unstable.

[0031] Therefore, by making the thrust block 45 axially movable, when a load difference occurs between the pair of biasing members 43, 43, the thrust block 45 moves axially toward the biasing member with the smaller load. The axial movement of the thrust block 45 due to the load difference stops when the loads on the pair of biasing members 43, 43 become equal. As a result, the preloads applied by the pair of biasing members 43, 43 to the pair of differential limiting units 5, 5 become equal, and the differential limiting characteristics (intermittent characteristics) of the pair of differential limiting units 5, 5 can be stabilized.

[0032] For example, suppose that the load applied by one biasing member 43 to one limiting differential unit 5 via one operating member 31 is the maximum value, and the load applied by the other biasing member 43 to the other limiting differential unit 5 via the other operating member 31 is the minimum value. In this case, the amount of movement of the thrust block 45 is maximum. The gap C that allows the thrust block 45 to move is set to be equal to or greater than the maximum amount of movement of the thrust block 45. Therefore, even if the load difference between the pair of biasing members 43, 43 is maximum, the thrust block 45 can be moved, and the limiting differential characteristics of the pair of limiting differential units 5, 5 can be stabilized.

[0033] Here, the axial gap between the gear portions of the pair of gear members 29, 29 and the gear portion of the pinion gear 11 in the axial direction of the side gears 13, 15 is set to be larger than the maximum movement amount of the thrust block 45. For this reason, even when the thrust block 45 moves to the maximum, the tops and bottoms of the gear teeth do not come into contact with each other in the gear portions of the pair of gear members 29, 29 and the pinion gear 11. Therefore, even when the load difference between the pair of biasing members 43, 43 is at its maximum, the thrust block 45 can be moved, and the differential limiting characteristics of the pair of differential limiting units 5, 5 can be stabilized.

[0034] In FIG. 1, the outer peripheral surface of pinion shaft 9 has recessed portions that are recessed toward the inner diameter side, but these portions are not for forming gap C. The recessed portions are provided in multiple locations around the circumference of pinion shaft 9 (for example, two locations equally spaced around the circumference). The recessed portions make it easier for lubricating oil that has flowed into differential case 7 to remain, thereby improving the lubrication between pinion shaft 9 and pinion gear 11.

[0035] Here, the differential case 7 has a split structure to have a case main body 17 and a cover body 19. By making the differential case 7 a split structure, for example, when adjusting the biasing force, the pair of biasing members 43, 43 can be easily removed and attached, and the design of the pair of biasing members 43, 43 can be easily changed.

[0036] The differential device 1 includes a rotatably arranged differential case 7 and a pinion gear 11 that is rotatably supported within the differential case 7 and revolves with the rotation of the differential case 7. The differential device 1 also includes a pair of side gears 13, 15 that mesh with the pinion gear 11 and are rotatable relative to each other, and a pair of differential limiting units 5, 5 that are provided between the differential case 7 and the pair of side gears 13, 15 and limit the differential movement of the pair of side gears 13, 15. The differential device 1 also includes a pair of biasing members 43, 43 that apply preloads to the pair of differential limiting units 5, 5, respectively, and a thrust block 45 that receives the load from the pair of biasing members 43, 43 that is applied to the pair of side gears 13, 15. Each of the pair of side gears 13, 15 includes a gear member 29 that meshes with the pinion gear 11 and an operating member 31 that is rotatable integrally with the gear member 29, is arranged axially movable, and operates the differential limiting unit 5. The biasing member 43 is disposed between the gear member 29 and the operating member 31, and applies a load to the gear member 29 to move the gear member 29 toward the inside in the axial direction of the side gears 13, 15. The thrust block 45 is disposed between the pair of gear members 29, 29, in contact with the pair of gear members 29, 29, and is disposed movably in the axial direction of the side gears 13, 15.

[0037] By allowing the thrust block 45 to move in the axial direction, when a load difference occurs between the pair of biasing members 43, 43, the thrust block 45 moves axially toward the biasing member with the smaller load. The axial movement of the thrust block 45 due to the load difference stops when the loads on the pair of biasing members 43, 43 become equal. As a result, the preloads applied by the pair of biasing members 43, 43 to the pair of differential limiting units 5, 5 become equal, and the differential limiting characteristics of the pair of differential limiting units 5, 5 can be stabilized.

[0038] Therefore, in such a differential device 1, the differential limiting characteristics of the differential limiting section 5 can be stabilized.

[0039] The pinion gear 11 is rotatably supported by a pinion shaft 9 that is arranged to be integrally rotatable in the differential case 7. A gap C is defined between the pinion shaft 9 and the thrust block 45, allowing the thrust block 45 to move in the axial direction of the side gears 13 and 15 relative to the pinion shaft 9.

[0040] Therefore, by adjusting the gap C between the pinion shaft 9 and the thrust block 45, the amount of movement of the thrust block 45 can be adjusted, and a wide range of load differences between the pair of biasing members 43, 43 can be accommodated.

[0041] Also, assume that the load applied by one biasing member 43 to one differential limiting unit 5 via one operating member 31 is the maximum value, and the load applied by the other biasing member 43 to the other differential limiting unit 5 via the other operating member 31 is the minimum value. The gap C at this time is set to be equal to or greater than the amount of movement of the thrust block 45 caused by the load difference between the pair of biasing members 43, 43.

[0042] Therefore, even if the load difference between the pair of biasing members 43, 43 is at its maximum, the thrust block 45 can be moved, and the differential limiting characteristics of the pair of differential limiting units 5, 5 can be stabilized.

[0043] The axial gap between the gear portions of the pair of gear members 29, 29 and the gear portion of the pinion gear 11 in the axial direction of the side gears 13, 15 is set to be larger than the amount of movement of the thrust block 45 caused by the (maximum) load difference between the pair of biasing members 43, 43.

[0044] For this reason, even when the thrust block 45 moves to the maximum extent, the top and bottom of the gear teeth do not come into contact with each other in the gear portions of the pair of gear members 29, 29 and the pinion gear 11. Therefore, even when the load difference between the pair of biasing members 43, 43 is at its maximum, the thrust block 45 can be moved, and the differential limiting characteristics of the pair of differential limiting units 5, 5 can be stabilized.

[0045] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

[0046] For example, in the differential device according to this embodiment, the differential limiting portion has a tapered ring arranged so that it can rotate integrally with the differential case, but this is not limited to this, and the operating member may be slid against the inner wall surface of the differential case without using a tapered ring.

[0047] Furthermore, the differential limiting portion is a cone clutch, but is not limited to this and may be a friction clutch such as a flat single-plate clutch or an alternating multiple-plate clutch.

[0048] In addition, in the differential device according to the present embodiment, the rotation axes of the pinion gear and the pair of side gears are arranged to intersect, and the gear portions mesh inside the differential case, which is a cross-axis type, but this is not limited to this. For example, the differential device may be a parallel-axis type, in which the rotation axes of the pinion gear and the pair of side gears are arranged parallel to the rotation axis of the differential case, and the gear portions mesh inside the differential case.

[0049] Furthermore, the biasing member is a disc spring, but is not limited to this and can be selected from coil-shaped, plate-shaped, wave-shaped, or other spring members, or elastically deformable (elastically deformable) members, taking into account the placement space and preload characteristics.

[0050] Furthermore, the number of biasing members is not limited to one, and a biasing member may be disposed on only one side. In this case, the load difference between the pair of biasing members is such that the load applied by the other biasing member to the other differential limiting portion exhibits the minimum value of 0.

[0051] Although different from the differential arrangement according to the present embodiment, a biasing member may be disposed between the pair of actuating members and the thrust block. In this case, the preload of the biasing member can be transmitted directly to the differential limiting portion. In addition, if a pair of biasing members is provided, the load of the pair of biasing members can be adjusted equally between the left and right. [Explanation of symbols]

[0052] 1 Differential device 5. Limited slip differential 7 Differential case 9 Pinion shaft 11 Pinion gear 13,15 Side gear 29 Gear parts 31 Actuating member 43 biasing member 45 Thrust Block C Gap

Claims

1. A rotatably arranged differential case; a pinion gear rotatably supported in the differential case and revolving with the rotation of the differential case; a pair of side gears that mesh with the pinion gear and are rotatable relative to each other; a pair of differential limiting units provided between the differential case and the pair of side gears, respectively, to limit differential between the pair of side gears; a pair of biasing members that apply preloads to the pair of differential limiting portions, respectively; a thrust block that receives a load from the pair of biasing members that is applied to the pair of side gears; Equipped with Each of the pair of side gears has a gear member that meshes with the pinion gear, and an operating member that is rotatable integrally with the gear member and axially movable, and that operates the differential limiting unit, the biasing member is disposed between the gear member and the operating member, and applies a load to the gear member that moves the gear member toward an inner side in the axial direction of the side gear; The thrust block is disposed between the pair of gear members, in contact with the pair of gear members, and movable in the axial direction of the side gear.

2. The pinion gear is rotatably supported by a pinion shaft arranged in the differential case so as to be integrally rotatable, 2. The differential device according to claim 1, wherein a gap is provided between the pinion shaft and the thrust block, allowing the thrust block to move in the axial direction of the side gear relative to the pinion shaft.

3. 3. The differential device according to claim 2, wherein the gap is set to be equal to or greater than the amount of movement of the thrust block caused by the load difference between the pair of biasing members when the load applied by one of the biasing members to one of the differential limiting portions via one of the operating members is at a maximum value and the load applied by the other of the biasing members to the other of the differential limiting portions via the other operating member is at a minimum value.

4. 4. The differential device according to claim 3, wherein an axial gap between the gear portions of the pair of gear members and the gear portion of the pinion gear in the axial direction of the side gear is set to be larger than an amount of movement of the thrust block caused by a load difference between the pair of biasing members.

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