Differential device

Abstract

[Problem] To provide a differential device which is provided with a friction clutch that suppresses differential rotation of a pair of output rotating members by frictional force, and an engagement member that prevents relative rotation of the pair of output rotating members by engagement of teeth, and which is capable of reducing the size of the device. [Solution] A differential device (1) is provided with: an input rotating member (2) that rotates about a rotation axis (O); a pair of output rotating members (31, 32) housed in the input rotating member (2) and rotating about a rotation axis (O); a plurality of differential gears (33, 34) capable of differentially rotating the pair of output rotating members (31, 32); an engagement member (4) that has dog teeth (41) that can engage with the output rotation member (32), and that does not rotate the output rotation member (32) relative to the input rotation member (2) by engaging with the output rotation member (32); and a friction clutch (5) that suppresses differential rotation between the output rotating member (32) and the input rotating member (3) by frictional force, the meshing member (4) being disposed on the inside of the friction clutch (5) in the radial direction perpendicular to the rotational axis (O).

Description

TECHNICAL FIELD

[0001] The present application relates to a differential device for distributing driving force to left and right wheels of a vehicle. BACKGROUND

[0002] In a vehicle, driving force of a driving source such as an engine is distributed to left and right wheels by a differential device. The differential device is provided with a differential gear mechanism having left and right side gears as a pair of output rotation members and a plurality of pinions meshing with the left and right side gears, and differential rotation of the left and right wheels at the time of cornering is enabled by the differential gear mechanism.

[0003] The differential devices described in Patent Documents 1 and 2 have, in addition to the differential gear mechanism, a friction clutch that inhibits differential rotation of the left and right wheels by frictional force, an engagement clutch that prohibits differential rotation of the left and right wheels by meshing of teeth, and a cam mechanism for causing the friction clutch and the engagement clutch to act. By inhibiting or prohibiting differential rotation of the left and right wheels, driving force is transmitted to the wheel on the other side, for example, in the case where the wheel on one side of the left and right wheels slips, and thus the drivability is improved. In the differential devices described in Patent Documents 1 and 2, the friction clutch, the engagement clutch, and the cam mechanism are arranged in parallel in an axial direction parallel to the vehicle width direction.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: U.S. Application Publication No. 2019 / 0348675

[0007] Patent Document 2: International Publication No. 2019 / 111294 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The differential devices described in Patent Documents 1 and 2 have the friction clutch and the engagement clutch, and thus the device size in the vehicle width direction is large. The large size of the device is a major factor in reducing the mountability to a vehicle.

[0010] Therefore, an object of the present application is to provide a differential device that has a friction clutch that inhibits differential rotation of a pair of output rotation members by frictional force and an engagement member that causes the pair of output rotation members to be unable to rotate relative to each other by meshing of teeth, and that enables downsizing of the device size.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] The differential device according to the present application is a differential device including: a housing-shaped input rotation member that is rotated about a rotation axis by a driving force of a driving source; a pair of output rotation members that are housed in the input rotation member and are rotated about the rotation axis; a plurality of differential gears that are housed in the input rotation member and allow differential rotation of the pair of output rotation members; an engagement member that has a toothed portion that is engaged with one of the pair of output rotation members and that is disengaged from the one of the pair of output rotation members by moving in an axial direction of the input rotation member, thereby allowing relative rotation of the one of the pair of output rotation members with respect to the input rotation member; and a friction clutch that is disposed between the one of the pair of output rotation members and the input rotation member and that inhibits differential rotation of the one of the pair of output rotation members with respect to the input rotation member by frictional force, wherein the engagement member is disposed inside the friction clutch in a radial direction perpendicular to the rotation axis.

[0013] Effects of the Invention

[0014] According to the differential device of the present application, it is possible to realize a reduction in size of the device. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a sectional view showing a structure example of the differential device according to the embodiment of the present application.

[0016] Figure 2 is an enlarged view showing a part of Figure 1 .

[0017] Figure 3 is a structure view showing an opposite surface of the rotation cam member with respect to the first driven cam member and the second driven cam member.

[0018] Figure 4 is a perspective sectional view of the rotation cam member showing a section of A-A line in Figure 3 .

[0019] Figure 5 is a structure view showing an opposite surface of the first driven cam member with respect to the rotation cam member.

[0020] Figure 6 is a structure view showing an opposite surface of the second driven cam member with respect to the rotation cam member.

[0021] Figure 7A is an explanatory view schematically showing a state in which neither the first thrust generating mechanism nor the second thrust generating mechanism is operated.

[0022] Figure 7Bis an explanatory view schematically showing an action state of the second thrust generating mechanism.

[0023] Figure 7C is an explanatory view schematically showing an action state of the first thrust generating mechanism.

[0024] Figure 7D is an explanatory view schematically showing an action state of the first thrust generating mechanism. DETAILED DESCRIPTION

[0025] [EMBODIMENT]

[0026] An embodiment of the present application will be described with reference to the drawings. Note that the following described embodiment is illustrated as a preferred specific example for embodying the present application, and there are parts that specifically illustrate various technical matters that are technically preferred, but the technical scope of the present application is not limited to this specific embodiment.

[0027] Figure 1 is a sectional view showing a structure example of a differential device 1 of the embodiment of the present application. Figure 2 is an enlarged view showing a part of Figure 1 . Also, in the following description, for convenience, the left side of Figure 1 and Figure 2 will be referred to as "left", and the right side will be referred to as "right", but the "left" and "right" do not necessarily mean left and right with respect to the advancing direction of the vehicle.

[0028] The differential device 1 is mounted on a vehicle, and is used to distribute the driving force of a driving source such as an engine or a motor to left and right wheels. In Figure 1 , a differential carrier 10, tubes 11, 12 installed to the left and right of the differential carrier 10, axle shafts 13, 14 housed in the left and right of the tubes 11, 12, a pinion shaft 16 supported so as to be rotatable with respect to the differential carrier 10 by a bearing 15, a ring gear 17 engaged with the pinion shaft 16, and bearings 18, 19 supporting the differential device 1 with respect to the differential carrier 10 are shown together with the differential device 1. The differential device 1 distributes the driving force of the driving source input from the pinion shaft 16 to the left and right axle shafts 13, 14 in a manner that allows differential. A lubricating oil not shown is enclosed in the inside of the differential carrier 10.

[0029] The differential device 1 has an input rotation member 2 in the shape of a housing that rotates with the rotational axis O as the center by the driving force of the driving source, a pinion shaft 30 fixed to the input rotation member 2, a pair of output rotation members 31, 32 linked to the left and right axle shafts 13, 14 in a manner that cannot rotate relative to each other, and a plurality of differential gears 33, 34 that can differentially rotate the output rotation members 31, 32. The output rotation members 31, 32 and the differential gears 33, 34 constitute a differential gear mechanism 3.

[0030] The output rotating members 31, 32 and the differential gears 33, 34 are housed in the input rotating member 2. The output rotating members 31, 32 rotate about the rotational axis O as a center. The differential gears 33, 34 are axially supported by the pinion shaft 30. In the present embodiment, the differential gears 33, 34 are bevel gears. The output rotating members 31, 32 are engaged with the differential gears 33, 34. The left side axle 13 is spline-engaged with the fitting hole 310 formed in the left side output rotating member 31 of the pair of output rotating members 31, 32. The right side axle 14 is spline-engaged with the fitting hole 320 formed in the right side output rotating member 32.

[0031] Hereinafter, a direction parallel to the rotational axis O is referred to as an axial direction, and a direction perpendicular to the rotational axis O is referred to as a radial direction. The pinion shaft 30 is disposed between the output rotating members 31, 32 and extends in the radial direction.

[0032] The input rotating member 2 has a hollow housing member 21 which is open to one side in the axial direction, and a cover member 22 which plugs the opening of the housing member 21. The housing member 21 is formed, for example, by casting. The cover member 22 is formed, for example, by forging. The cover member 22 is fixed to the housing member 21 and rotates integrally with the housing member 21. The housing member 21 has a flange portion 211 which fixes the ring gear 17. The ring gear 17 is fixed to the flange portion 211 by a plurality of bolts 171. A driving force of a driving source is input to the input rotating member 2 from the ring gear 17. Alternatively, the ring gear 17 can be fixed to the housing member 21 by welding.

[0033] The housing member 21 is formed with a fitting hole 212 through which the left side axle 13 is inserted, and holding holes 213, 214 which respectively hold both end portions of the pinion shaft 30. Movement of the pinion shaft 30 relative to the housing member 21 is restricted by a pin 210 which is pressed into the housing member 21 in the axial direction.

[0034] A washer 351 is disposed between the left side output rotating member 31 and the housing member 21. Further, washers 352, 353 are respectively disposed between the differential gears 33, 34 and the housing member 21. The left side output rotating member 31 integrally has a gear tooth 311 which engages with the differential gears 33, 34, and a cylindrical boss portion 312 which is fitted into the fitting hole 212 of the housing member 21.

[0035] The cover member 22 integrally has a large-diameter cylindrical portion 221 and a small-diameter cylindrical portion 222, a wall portion 223 of a circular ring plate shape, and an outer side cylindrical portion 224 extending from an outer peripheral end portion of the wall portion 223 in the axial direction. The outer diameter and the inner diameter of the large-diameter cylindrical portion 221 are formed larger than the outer diameter and the inner diameter of the small-diameter cylindrical portion 222. The right side axle 14 is inserted through the inside of the large-diameter cylindrical portion 221 and the small-diameter cylindrical portion 222. The wall portion 223 is formed to protrude to the radial direction outside from the large-diameter cylindrical portion 221. The axial one end portion of the outer side cylindrical portion 224 is welded to the case member 21. A washer 354 is disposed between the right side output rotation member 32 and the axial one end portion of the large-diameter cylindrical portion 221.

[0036] The case member 21 of the input rotation member 2 is supported by the bearing 18 so as to be rotatable with respect to the differential carrier 10, and the small-diameter cylindrical portion 222 of the cover member 22 is supported by the bearing 19 so as to be rotatable with respect to the differential carrier 10. The bearings 18, 19 are tapered roller bearings, and have inner rings 181, 191, outer rings 182, 192, a plurality of rolling elements 183, 193 of a partial conical shape disposed between the inner rings 181, 191 and the outer rings 182, 192, and retainer rings 184, 194 that hold the plurality of rolling elements 183, 193. Washers 180, 190 for play adjustment are respectively disposed between the outer rings 182, 192 and the differential carrier 10.

[0037] Further, the differential device 1 has the engagement member 4 that makes the right side output rotation member 32 unable to relatively rotate with respect to the input rotation member 2, and the friction clutch 5 that suppresses differential rotation of the right side output rotation member 32 and the input rotation member 2 by frictional force. Since the right side output rotation member 32 and the left side output rotation member 31 are linked by the differential gears 33, 34, the right side output rotation member 32 is unable to relatively rotate with respect to the input rotation member 2 by the engagement member 4, and thus the left side output rotation member 31 is also unable to relatively rotate with respect to the input rotation member 2. Further, by suppressing the differential rotation of the right side output rotation member 32 and the input rotation member 2 by the friction clutch 5, the differential rotation of the left side output rotation member 31 and the input rotation member 2 is also suppressed. By making or suppressing the differential rotation of the output rotation members 31, 32 and the input rotation member 2, it is possible to suppress the idling of the left and right wheels, improve the passability of the vehicle, and for example, stably travel on a rough road or a low μ road.

[0038] The engagement member 4 is spline-fitted to the large-diameter cylindrical portion 221 in a manner capable of moving in the axial direction and unable to relatively rotate. The engagement member 4 is disposed between the output rotation member 32 and the wall portion 223 of the cover member 22. As described above, the engagement member 4 is disposed in the large-diameter cylindrical portion 221 of the cover member 22 in a manner capable of moving in the axial direction and unable to relatively rotate. The engagement member 4 is disposed between the output rotation member 32 and the wall portion 223 of the cover member 22. Figure 2As shown, the engagement member 4 has a plurality of dog teeth 41 that can engage with the output rotating member 32. The engagement member 4 engages the plurality of dog teeth 41 with the output rotating member 32 by axial movement relative to the input rotating member 2, thereby making the output rotating member 32 unable to relatively rotate relative to the input rotating member 2.

[0039] The friction clutch 5 is disposed between the output rotating member 32 and the outer cylindrical portion 224 of the cover member 22. The friction clutch 5 has a plurality of outer clutch plates 51 that can axially move and are unable to relatively rotate relative to the input rotating member 2, a plurality of inner clutch plates 52 that can axially move and are unable to relatively rotate relative to the output rotating member 32, and a pressure plate 53 that is disposed opposite the cover member 22. The plurality of outer clutch plates 51 and the plurality of inner clutch plates 52 are alternately disposed along the axial direction. The pressure plate 53 is juxtaposed with the plurality of outer clutch plates 51 and inner clutch plates 52 in the axial direction, and can axially move and is unable to relatively rotate relative to the input rotating member 2.

[0040] The output rotating member 32 integrally has a gear tooth 321 that engages with the differential gears 33, 34, a cylindrical boss portion 322 that is fitted into the large-diameter cylindrical portion 221 of the cover member 22, an outer peripheral spline fitting portion 323 in which outer spline teeth 323a that engage with the plurality of inner clutch plates 52 are formed, and an engagement portion 324 in which a plurality of engagement teeth 324a that engage with the plurality of dog teeth 41 of the engagement member 4 are formed.

[0041] In the radial direction perpendicular to the rotational axis O, the engagement member 4 is disposed inside the friction clutch 5. The engagement portion 324 of the output rotating member 32 is disposed inside the outer peripheral spline fitting portion 323 in the radial direction.

[0042] Further, the differential device 1 has: a first pressing member 61 that presses the engagement member 4 in the axial direction; a second pressing member 62 that presses the friction clutch 5 in the axial direction; a first driven cam member 63 that is arranged in parallel with the first pressing member 61 in the axial direction; a second driven cam member 64 that is arranged in parallel with the second pressing member 62 in the axial direction; a rotating cam member 65 that is arranged opposite to the first driven cam member 63 and the second driven cam member 64 in the axial direction; a plurality of cam balls 661 and a retainer 662 that are arranged between the second driven cam member 64 and the rotating cam member 65; a first thrust bearing 67 that is arranged between the first pressing member 61 and the first driven cam member 63; a second thrust bearing 68 that is arranged between the second pressing member 62 and the second driven cam member 64; a first urging member 691 that elastically urges the first pressing member 61 toward the first thrust bearing 67; a second urging member 692 that elastically urges the second pressing member 62 toward the second thrust bearing 68; and a bearing 60 that is arranged between the rotating cam member 65 and the cover member 22. The cam balls 661 are spherical. The retainer 662 holds the plurality of cam balls 661 at equal intervals in the circumferential direction.

[0043] In the present embodiment, the first pressing member 61 integrally has a cylindrical shaft portion 611 and a head portion 612 that is larger in diameter than the shaft portion 611. The differential device 1 has a plurality of first pressing members 61. The plurality of first pressing members 61 are arranged in parallel with the first thrust bearing 67 in the axial direction, and are arranged at the outer periphery of the large-diameter cylindrical portion 221 of the cover member 22.

[0044] A plurality of first through holes 223a through which the shaft portions 611 of the plurality of first pressing members 61 are respectively inserted are formed in the wall portion 223 of the cover member 22. The first through holes 223a are formed through the inside and outside of the input rotating member 2 in the axial direction. The plurality of first pressing members 61 are movable in the axial direction with respect to the input rotating member 2. The head portions 612 of the first pressing members 61 are arranged outside the input rotating member 2 together with the first urging members 691.

[0045] An engagement hole 42 into which one end of the shaft portion 611 of each of the plurality of first pressing members 61 is press-fitted is formed in the engagement member 4. The plurality of first pressing members 61 are fixed to the engagement member 4 by being press-fitted into the engagement holes 42. However, the method of fixing the engagement member 4 and the first pressing members 61 is not limited thereto, and the first pressing members 61 can be fixed to the engagement member 4 by a locking member such as a snap ring.

[0046] The engagement member 4 moves in the axial direction together with the plurality of first pressing members 61. When the engagement member 4 moves toward the output rotating member 32 side, the toothing 41 of the engagement member 4 engages with the engagement portion 324 of the output rotating member 32, so that the engagement member 4 and the output rotating member 32 cannot rotate with respect to each other.

[0047] The first urging member 691 is a disc spring formed with a plurality of cutouts 691a. The shaft portions 611 of the first pressing members 61 are inserted through the cutouts 691a of the first urging member 691. The first urging member 691 abuts against the head portions 612 of the respective first pressing members 61 to urge the head portions 612 of the first pressing members 61 to separate from the wall portion 223 of the cover member 22 in the axial direction.

[0048] The first thrust bearing 67 has a plurality of rollers 671, a retainer 672 that retains the plurality of rollers 671, and a thrust race 673 that is a circular ring plate through which the plurality of rollers 671 roll. The head portions 612 of the respective first pressing members 61 abut against the thrust race 673.

[0049] The second pressing member 62 integrally has a base portion 621 that is a flat plate and a plurality of protrusions 622 that are cylindrical and extend in the axial direction. The base end portions of the protrusions 622 in the axial direction are continuous with the base portion 621. The base portion 621 is formed in a ring shape, is arranged in parallel with the second thrust bearing 68 in the axial direction, and is arranged at the outer periphery of the first pressing members 61. The wall portion 223 of the cover member 22 is formed with a plurality of second through holes 223b through which the plurality of protrusions 622 of the second pressing member 62 are respectively inserted. The second through holes 223b are formed so as to pass through the inside and outside of the input rotation member 2 in the axial direction. The base portion 621 is arranged outside the input rotation member 2 together with the second urging member 692.

[0050] The plurality of protrusions 622 of the second pressing member 62 are opposed to the pressure plate 53 of the friction clutch 5 in the axial direction. The second pressing member 62 is movable in the axial direction with respect to the input rotation member 2, and when the second pressing member 62 moves toward the friction clutch 5 side, the plurality of outer clutch plates 51 and the plurality of inner clutch plates 52 are brought into frictional contact to generate a frictional force, and differential rotation of the output rotation member 32 and the input rotation member 2 is suppressed. Frictional sliding of the outer clutch plates 51 and the inner clutch plates 52 is lubricated by lubricating oil.

[0051] The second urging member 692 is a disc spring formed with a plurality of cutouts 692a. The protrusions 622 of the second pressing member 62 are inserted through the cutouts 692a of the second urging member 692. The second urging member 692 abuts against the base portion 621 of the second pressing member 62 to urge the base portion 621 to separate from the wall portion 223 of the cover member 22 in the axial direction.

[0052] The second thrust bearing 68 has a plurality of rollers 681 and a retainer 682 that retains the plurality of rollers 681. The plurality of rollers 681 roll on the base portion 621 of the second pressing member 62.

[0053] The first driven cam member 63 is disposed radially inward of the second driven cam member 64. The first driven cam member 63 and the second driven cam member 64 are relatively movable in the axial direction and are non-rotatably engaged. More specifically, the second driven cam member 64 is spline-fitted to the inner side of the first driven cam member 63. The first driven cam member 63 and the second driven cam member 64 are moved in the axial direction relative to the differential case 10 by the rotational cam member 65 being rotated relative to the differential case 10.

[0054] The differential device 1 has, as a structure for rotating the rotational cam member 65 relative to the differential case 10, a motor 71 fixed to the differential case 10, a reduction gear 72 having a large-diameter gear portion 721 and a small-diameter gear portion 722, a support member 73 supporting the reduction gear 72 so as to be rotatable relative to the differential case 10, and a control device 8 controlling the motor 71. The reduction gear 72 has a disc-shaped plate portion 723 inside the large-diameter gear portion 721. The pitch circle diameter of the large-diameter gear portion 721 in the reduction gear 72 is formed larger than the pitch circle diameter of the small-diameter gear portion 722.

[0055] The control device 8 can recognize the operation state of a mode selection switch 9 operated by the driver of the vehicle. The mode selection switch 9 can select a normal mode in which the engagement member 4 is not engaged with the engagement portion 324 of the output rotation member 32 and the friction clutch 5 is not pressed, an automatic mode in which the friction clutch 5 generates a friction force appropriate for the running state of the vehicle, and a lock mode in which the engagement member 4 is engaged with the engagement portion 324 of the output rotation member 32 so that the left and right output rotation members 31, 32 cannot rotate relative to each other.

[0056] The motor 71 has a motor case 711 fixed to the differential case 10 and an output rotation shaft 712 formed with a gear portion 712a. Inside the motor case 711 are housed a stator 71a fixed to the motor case 711, a rotor 71b that rotates relative to the stator 71a and the output rotation shaft 712 as one body, and a position detector 71c that detects the position of the rotor 71b relative to the stator 71a. The position detector 71c is, for example, an encoder or a resolver. The motor 71 rotates the output rotation shaft 712 relative to the motor case 711 by supplying a current from the control device 8. The gear portion 712a of the output rotation shaft 712 is engaged with the large-diameter gear portion 721 of the reduction gear 72.

[0057] The second driven cam member 64 has an engaging portion 641 that engages with the support member 73, and is rotationally fixed with respect to the differential case 10 by the support member 73. Further, the second driven cam member 64 is axially movable along the support member 73 while the engaging portion 641 is engaged with the support member 73. The first driven cam member 63 is axially movable and non-rotatable with respect to the differential case 10 by being spline-fitted to the second driven cam member 64, like the second driven cam member 64.

[0058] The bearing 60 rotationally supports the rotary cam member 65 with respect to the input rotation member 2. The bearing 60 is an angular contact ball bearing having an inner ring 601 and an outer ring 602, a plurality of spherical rolling elements 603 disposed between the inner ring 601 and the outer ring 602, and a cage 604 that holds the plurality of rolling elements 603. The inner ring 601 is externally fitted to the small-diameter cylindrical portion 222 of the cover member 22, and is axially aligned with the inner ring 191 of the bearing 19. Axial movement of the inner ring 601 in a direction away from the large-diameter cylindrical portion 221 is restricted by the inner ring 191 of the bearing 19.

[0059] The rotary cam member 65 is engaged with the small-diameter gear portion 722 of the reduction gear 72 to rotate at a lower speed than the reduction gear 72. Axial movement of the rotary cam member 65 in a direction away from the first driven cam member 63 and the second driven cam member 64 is restricted by the bearing 60.

[0060] Figure 3 FIG. 6 is a structural view showing an opposite surface of the rotary cam member 65 opposite the first driven cam member 63 and the second driven cam member 64. Figure 4 FIG. 7 is a sectional view of the rotary cam member 65 taken along the A-A line in FIG. 6. Figure 3 FIG. 7 is a sectional view of the rotary cam member 65 taken along the A-A line in FIG. 6.

[0061] The rotary cam member 65 integrally has a first cam portion 651 opposite the first driven cam member 63 in the axial direction, a second cam portion 652 opposite the second driven cam member 64 in the axial direction, and a gear portion 653 engaged with the small-diameter gear portion 722 of the reduction gear 72. A bearing-fitting portion 650 into which the outer ring 602 of the bearing 60 is fitted is formed at an inner peripheral end portion of the rotary cam member 65.

[0062] The first cam portion 651 is provided at an inner peripheral side of the second cam portion 652. The gear portion 653 is provided at an outer peripheral side of the second cam portion 652. The gear portion 653 has a circular arc shape when viewed in the axial direction. A protrusion 653a that abuts against the plate portion 723 of the reduction gear 72 is provided at an opposite surface of the gear portion 653 opposite the plate portion 723. The protrusion 653a defines a position of the gear portion 653 in the axial direction with respect to the reduction gear 72.

[0063] A plurality of cam sliding surfaces 651a are formed in the first cam portion 651. The cam sliding surfaces 651a extend in a circumferential direction of the rotation cam member 65 to be formed in a circular arc shape. In the present embodiment, five cam sliding surfaces 651a are formed in the first cam portion 651. Each of the cam sliding surfaces 651a has a vertical surface 651b orthogonal to the axial direction and a seating surface 651d, and an inclined surface 651c formed between the vertical surface 651b and the seating surface 651d. The inclined surface 651c is inclined with respect to the axial direction. The seating surface 651d is formed at the first driven cam member 63 side than the vertical surface 651b in the axial direction.

[0064] In the second cam portion 652, a plurality of cam grooves 652b recessed in the axial direction from an opposite surface 652a opposite to the second driven cam member 64 are formed in a circular arc shape. The cam grooves 652b have a deep groove portion 652c having a fixed depth from the axial direction of the opposite surface 652a, and an inclined groove portion 652d gradually shallower in depth from the axial direction of the opposite surface 652a than the deep groove portion 652c. The deeper the inclined groove portion 652d is from the deep groove portion 652c, the shallower the depth is.

[0065] In the present embodiment, five cam grooves 652b are formed in the second cam portion 652. In the radial direction of the rotation cam member 65, the plurality of cam grooves 652b are formed outside the plurality of cam sliding surfaces 651a.

[0066] Figure 5 is a structural view of an opposite surface of the first driven cam member 63 opposite to the rotation cam member 65. On the first driven cam member 63, like the first cam portion 651 of the rotation cam member 65, a plurality of cam sliding surfaces 63a are formed. Each of the cam sliding surfaces 63a is formed in a circular arc shape in a manner opposite to the cam sliding surfaces 651a of the first cam portion 651 in the axial direction, has a vertical surface 63b orthogonal to the axial direction and a seating surface 63d, and an inclined surface 63c formed between the vertical surface 63b and the seating surface 63d inclined with respect to the axial direction. The seating surface 63d is formed at the rotation cam member 65 side than the vertical surface 63b in the axial direction. A spline fitting portion 631 is provided at an outer peripheral end portion of the first driven cam member 63.

[0067] Figure 6is a structural view showing the opposite face of the second driven cam member 64 opposite to the rotating cam member 65. In the second driven cam member 64, a plurality of cam grooves 64b formed by recessing from the opposite face 64a opposite to the rotating cam member 65 toward the axial direction extend in a circular arc shape along the circumferential direction of the second driven cam member 64. Each of the cam grooves 64b has a deep groove portion 64c having a fixed depth from the axial direction of the opposite face 64a and a sloped groove portion 64d having a depth from the axial direction of the opposite face 64a gradually shallower from the deep groove portion 64c. The deeper the sloped groove portion 64d is from the deep groove portion 64c, the shallower the depth is. At the inner circumferential end portion of the second driven cam member 64, a spline fitting portion 642 into which the spline fitting portion 631 of the first driven cam member 63 is fitted is provided.

[0068] The first driven cam member 63, the first thrust bearing 67, and the first cam portion 651 of the rotating cam member 65 constitute a first thrust generating mechanism 6A that applies an axial thrust to the plurality of first pressing members 61. The second driven cam member 64, the second thrust bearing 68, and the second cam portion 652 of the rotating cam member 65 constitute a second thrust generating mechanism 6B that applies an axial thrust to the second pressing member 62. In the radial direction of the differential device 1, the first thrust generating mechanism 6A is disposed inside the second thrust generating mechanism 6B.

[0069] The first thrust generating mechanism 6A is a sliding cam mechanism that applies an axial thrust to the plurality of first pressing members 61 by the relative rotation between the first driven cam member 63 and the rotating cam member 65. The second thrust generating mechanism 6B is a ball cam mechanism that applies an axial thrust to the second pressing member 62 by causing the cam ball 661 to roll in the sloped groove portion 652d of the cam groove 652b of the rotating cam member 65 and the sloped groove portion 64d of the cam groove 64b of the second driven cam member 64.

[0070] Figures 7A to 7D is an explanatory view for explaining the operation of the first thrust generating mechanism 6A and the second thrust generating mechanism 6B. Figure 7A A state in which neither the first thrust generating mechanism 6A nor the second thrust generating mechanism 6B operates is schematically shown. Figure 7B A state in which the second thrust generating mechanism 6B operates is schematically shown. Figure 7C and 7D A state in which the first thrust generating mechanism 6A operates is schematically shown. In Figures 7A to 7D In the above-described embodiment, the up-down direction of the drawing corresponds to the axial direction of the differential device 1.

[0071] In the non-operating state of the first thrust generating mechanism 6A, the entire base surface 651d of the cam sliding surface 651a of the rotating cam member 65 faces the vertical surface 63b of the cam sliding surface 63a of the first driven cam member 63 in the axial direction, and the entire base surface 63d of the cam sliding surface 63a of the first driven cam member 63 faces the vertical surface 651b of the cam sliding surface 651a of the rotating cam member 65 in the axial direction. When the first thrust generating mechanism 6A is in the non-operating state, the axial position of the first driven cam member 63 becomes furthest away from the wall portion 223 of the cover member 22 due to the force applied by the first force applying member 691, and the plurality of teeth 41 of the engaging member 4 do not engage with the engaging portion 324 of the output rotating member 32.

[0072] In the non-operating state of the second thrust generating mechanism 6B, the cam ball 661 is located in the deep groove portion 652c of the cam groove 652b of the rotating cam member 65 and the deep groove portion 64c of the cam groove 64b of the second driven cam member 64. When the second thrust generating mechanism 6B is in the non-operating state, the axial position of the second driven cam member 64 is changed to the position furthest from the wall portion 223 of the cover member 22 due to the force applied by the second force applying member 692, and the friction clutch 5 is not pressed in the axial direction.

[0073] like Figure 7A As shown, when both the first thrust generating mechanism 6A and the second thrust generating mechanism 6B are in a non-operating state, the relative rotation of the left output rotating member 31 and the right output rotating member 32 is not hindered by the meshing member 4 and the friction clutch 5, and the driving force transmitted to the left and right wheels is approximately equal.

[0074] Figure 7B Indicates that the rotary cam component 65 is from Figure 7A The state shown is the state of movement to the left of the attached figure. In this state, the cam ball 661 rolls and moves towards the inclined groove 652d of the cam groove 652b of the rotating cam member 65 and the inclined groove 64d of the second driven cam member 64, generating a position in the second driven cam member 64. Figure 7B The cam thrust is axial, as indicated by the middle arrow. Furthermore, through this cam thrust, the second pressing member 62 presses the friction clutch 5 axially, generating friction between the plurality of outer clutch plates 51 and the plurality of inner clutch plates 52. On the other hand, in the first driven cam member 63, the entire base surface 63d of the cam sliding surface 63a faces axially upwards towards the vertical surface 651b of the cam sliding surface 651a of the rotating cam member 65, and the second thrust generating mechanism 6B remains in a non-operating state.

[0075] Figure 7C Indicates that the rotary cam component 65 is from Figure 7AThe state shown is one where the cam sliding surface 651a of the rotating cam member 65 has moved to the right of the attached figure, and the inclined surface 651c of the cam sliding surface 651a of the rotating cam member 65 is in contact with the inclined surface 63c of the cam sliding surface 63a of the first driven cam member 63. In this state, the inclined surface 651c of the cam sliding surface 651a of the rotating cam member 65 slides on the inclined surface 63c of the cam sliding surface 63a of the first driven cam member 63, generating... Figure 7C The cam thrust is indicated by the middle arrow. Multiple first pressing members 61 press the engaging member 4 towards the engaging portion 324 of the output rotating member 32 via the cam thrust, and the engaging member 4 engages with the engaging portion 324. On the other hand, the second thrust generating mechanism 6B maintains the cam ball 661 in the deep groove portions 652c and 64c of the cam grooves 652b and 64b, keeping it in a non-operating state.

[0076] Figure 7D Indicates that the rotary cam component 65 is from Figure 7C The state shown is further moved to the right of the attached figure, with the pedestal surface 651d of the cam sliding surface 651a of the rotating cam member 65 in contact with the pedestal surface 63d of the cam sliding surface 63a of the first driven cam member 63. In this state, the first driven cam member 63 does not generate cam thrust, but it prevents the engagement member 4 from moving in the direction of separation from the engagement portion 324 of the output rotating member 32, and maintains the engagement of the teeth 41 of the engagement member 4 with the engagement teeth 324a of the engagement portion 324. The second thrust generating mechanism 6B remains in a non-operating state.

[0077] When the normal mode is selected via the mode selection switch 9, the control device 8 controls the motor 71 to set the position of the rotating cam member 65 relative to the first driven cam member 63 and the second driven cam member 64. Figure 7A The control device 8 sets the first thrust generating mechanism 6A and the second thrust generating mechanism 6B to the non-operating state at the indicated position. Additionally, when the automatic mode is selected via the mode selection switch 9, the control device 8 activates the second thrust generating mechanism 6B according to the vehicle's driving state, causing the friction clutch 5 to generate friction.

[0078] When the mode selection switch 9 selects the locked mode, the control device 8 controls the motor 71 to activate the first thrust generating mechanism 6A, causing the meshing member 4 to mesh with the meshing portion 324 of the output rotating member 32. Since the base surface 651d of the cam sliding surface 651a of the first cam portion 651 and the base surface 63d of the cam sliding surface 63a of the first driven cam member 63 are both planes perpendicular to the axial direction, even when the teeth 41 of the meshing member 4 receive an axial meshing reaction force from the meshing teeth 324a of the meshing portion 324, the meshing reaction force is not used as a torque to rotate the rotating cam member 65.

[0079] Therefore, during running of the vehicle in the locked mode, the electric current supplied to the motor 71 can be cut off. Even if the supply of the electric current to the motor 71 is cut off, the state in which the land face 651d of the cam sliding face 651a of the rotating cam member 65 is in contact with the land face 63d of the cam sliding face 63a of the first driven cam member 63 is maintained by the rotational resistance of the rotating cam member 65, the reduction gear 72, and the rotor 71b of the motor 71.

[0080] The control device 8 detects the case where the land face 651d of the cam sliding face 651a of the rotating cam member 65 is in contact with the land face 63d of the cam sliding face 63a of the first driven cam member 63 by, for example, the detected value of the position detector 71c of the motor 71, and sets the electric current supplied to the motor 71 to zero. Thus, the consumed electric current of the motor 71 can be reduced. Further, when it is detected that the rotor 71b of the motor 71 rotates with respect to the stator 71a due to vibration or the like during running of the vehicle in the locked mode, the supply of the electric current to the motor 71 is temporarily resumed to return the position of the rotor 71b, and then the supply of the electric current to the motor 71 is cut off again.

[0081] (EFFECTS OF THE EMBODIMENT)

[0082] According to the present embodiment described above, by the configuration structure in which the engaging member 4 is disposed inside the friction clutch 5, compared with the case where the engaging member 4 and the friction clutch 5 are disposed in parallel in the axial direction, the length of the differential device 1 in the axial direction can be shortened, and the device size can be downsized. Further, by the configuration structure in which the engaging portion 324 of the output rotating member 32 is disposed inside the outer peripheral spline fitting portion 323, and the configuration structure in which the first thrust force generating mechanism 6A is disposed inside the second thrust force generating mechanism 6B, the length of the differential device 1 in the axial direction can be shortened, and the device size can be downsized. Further, the electric current supplied to the motor 71 can be cut off during running of the vehicle in the locked mode, and thus the consumed electric power of the motor 71 can be reduced.

[0083] (POSTSCRIPT)

[0084] The present application has been described based on the embodiment, but the embodiment does not limit the application covered by the claims. It should be noted that a combination of features described in the embodiment is not necessarily all the means necessary to solve the problems of the application. Further, the present application can omit a part of the structure, or add or replace the structure, and be appropriately modified without departing from the gist thereof. Further, for example, the present application can be modified and implemented as follows.

[0085] In the above-described embodiments, the case where the output rotation member 32 integrally has the gear teeth 321, the boss portion 322, the outer peripheral spline fitting portion 323, and the engagement portion 324 has been described, but the present application is not limited thereto, and for example, a first member integrally having the gear teeth 321 and the boss portion 322 and a second member having the outer peripheral spline fitting portion 323 and the engagement portion 324 can be combined in a manner that they cannot rotate relative to each other to constitute the output rotation member 32.

[0086] In the above-described embodiments, the case where the friction clutch 5 and the engagement member 4 are disposed in correspondence with the right-side output rotation member 32 among the left and right output rotation members 31, 32 has been described, but the present application is not limited thereto, and the friction clutch 5 and the engagement member 4 can be disposed in correspondence with the left-side output rotation member 31. That is, the friction clutch 5 and the engagement member 4 can be disposed in correspondence with either of the left and right output rotation members 31, 32.

[0087] In the above-described embodiments, the case where the plurality of first pressing members 61 are fixed to the engagement member 4 by press-fitting has been described, but the present application is not limited thereto, and a flat plate-shaped base portion and a plurality of cylindrical projection portions extending in the axial direction can be combined to constitute a single first pressing member, and the engagement member 4 can be pressed by the single first pressing member, like the second pressing member 62.

[0088] In the above-described embodiments, the case where the current supplied to the motor 71 is cut off when the vehicle is running in the locked mode has been described, but the present application is not limited thereto, and a small current that can suppress the rotation of the rotor 71b relative to the stator 71a of the motor 71 can be continuously supplied to the motor 71.

[0089] BRIEF DESCRIPTION OF THE DRAWINGS

[0090] 1…differential

[0091] 2…input rotation member

[0092] 31, 32…output rotation member

[0093] 323…outer peripheral spline fitting portion

[0094] 323a…external spline

[0095] 324…engagement portion

[0096] 324a…engagement teeth

[0097] 33, 34…differential gear

[0098] 4…engagement member

[0099] 41…dog teeth

[0100] 5 friction clutch

[0101] 51 outer clutch plate

[0102] 52 inner clutch plate

[0103] 6A first thrust generating mechanism

[0104] 6B second thrust generating mechanism

[0105] 60 bearing

[0106] 61 first pressing member

[0107] 62 second pressing member

[0108] 63 first driven cam member

[0109] 63a cam sliding surface

[0110] 63b vertical surface

[0111] 63c inclined surface

[0112] 63d abutment surface

[0113] 64 second driven cam member

[0114] 64b cam groove

[0115] 64c deep groove portion

[0116] 64d inclined groove portion

[0117] 65 rotary cam member

[0118] 651a cam sliding surface

[0119] 651b vertical surface

[0120] 651c inclined surface

[0121] 651d abutment surface

[0122] 652b cam groove

[0123] 652c deep groove portion

[0124] 652d inclined groove portion

[0125] 661 cam ball

[0126] O rotational axis

Claims

1. A differential device, wherein, The differential device includes: A shell-shaped input rotating component is driven by the driving force of an input driving source and rotates about a rotation axis. A pair of output rotating members are housed within the input rotating member and rotate about the rotation axis. Multiple differential gears are housed in the input rotating member, enabling the pair of output rotating members to rotate differentially; The engaging member has a toothed engagement mechanism capable of engaging one of the pair of output rotating members. The toothed engagement mechanism is caused by axial movement relative to the input rotating member, thereby preventing the output rotating member from rotating relative to the input rotating member. and A friction clutch, disposed between the output rotating member and the input rotating member, uses friction to suppress differential rotation between the output rotating member and the input rotating member. The engagement member is disposed inside the friction clutch in a radial direction perpendicular to the axis of rotation.

2. The differential device according to claim 1, wherein, The friction clutch comprises: a plurality of outer clutch plates, which are axially movable relative to the input rotating member but cannot rotate relative to it; and a plurality of inner clutch plates, which are axially movable relative to the output rotating member but cannot rotate relative to it. The output rotating member has: an outer peripheral spline engagement portion, forming an external toothed spline for engaging with the plurality of inner clutch plates; and a meshing portion, forming meshing teeth that engage with the toothed teeth of the meshing member. In the radial direction perpendicular to the axis of rotation, the engagement portion is located inside the outer peripheral spline engagement portion.

3. The differential device according to claim 2, wherein, The differential device includes: a first pressing member that presses the engaging member axially; a second pressing member that presses the friction clutch axially; a first thrust generating mechanism that applies an axial thrust to the first pressing member; and a second thrust generating mechanism that applies an axial thrust to the second pressing member. In the radial direction perpendicular to the axis of rotation, the first thrust generating mechanism is disposed inside the second thrust generating mechanism.

4. The differential device according to claim 3, wherein, The first thrust generating mechanism is a sliding cam mechanism. This mechanism applies an axial thrust to the first pressing member through the relative rotation of a rotating cam member with a cam sliding surface and a first driven cam member disposed opposite to the rotating cam member. The cam sliding surface has an inclined surface tilted relative to the axial direction and a base surface perpendicular to the axial direction. A portion of the first driven cam member slides on the inclined surface, thereby pressing the first pressing member toward the engaging portion of the output rotating member, and a portion of the first driven cam member abuts against the base surface, thereby maintaining the engagement of the teeth of the engaging member with the engaging teeth of the engaging portion.

5. The differential device according to claim 4, wherein, The second thrust generating mechanism is a ball cam mechanism, which applies an axial thrust to the second pressing member by having a spherical rolling element roll in an inclined groove portion of a cam groove formed in the rotating cam member at an angle relative to the axial direction. The cam groove is formed on the outer side of the cam sliding surface in a radial direction perpendicular to the axis of rotation.

6. The differential device according to claim 5, wherein, The differential device includes bearings that support the rotary cam member so that it can rotate relative to the input rotary member. The movement of the rotating cam member in the direction of separation from the first driven cam member is restricted by the bearing.

7. The differential device according to claim 5 or 6, wherein, The second thrust generating mechanism has a second driven cam member configured opposite to the rotary cam member. In the radial direction perpendicular to the axis of rotation, the first driven cam member is disposed inside the second driven cam member.

8. The differential device according to claim 7, wherein, The first driven cam member and the second driven cam member are engaged in a manner that allows them to move relative to each other in the axial direction but prevents them from rotating relative to each other.

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