Differential device for vehicle

Abstract

The present invention provides a vehicle differential device capable of suppressing an increase in differential limiting force caused by thermal expansion of a gear in a differential case while suppressing a decrease in responsiveness of the differential limiting force. A differential device (1) for a vehicle is provided with: a plurality of pinion sets (2); a first half axle gear set (3) formed by helical spline fitting of a first outer gear member (31) and a first inner gear member (32); a second half axle gear set (4) formed by helical spline fitting of a second outer gear member (41) and a second inner gear member (42); a differential case (10) having a cylindrical section (110) for holding the plurality of pinion sets (2), and first and second side wall sections (111, 121); a first end washer (51) and a first disc spring (61) disposed between the first half axle gear set (3) and the first side wall portion (111); and a second end washer (52) and a second disc spring (62) disposed between the second half axle gear set (4) and the second side wall portion (121).

Description

Technical Field

[0001] The present invention relates to a vehicle differential device having a differential limiting function. Background Art

[0002] Conventionally, among the differential devices that distribute the driving force of the driving source of the vehicle to the left and right wheels in a differentially-permitted manner, there are differential devices that have a differential limiting function that limits the differential rotation of the left and right wheels. Such a differential device can transmit the driving force to the wheel on the other side even when one of the left and right wheels slips, thereby improving the driving stability.

[0003] The differential device described in Patent Document 1 includes: a plurality of planetary gear pairs, each formed by meshing a pair of planetary gears; a first sun gear meshing with one of the pair of planetary gears; a second sun gear meshing with the other of the pair of planetary gears; and a differential case (housing) for accommodating them. The differential case has a cylindrical portion having a retaining hole for retaining a plurality of planetary gear pairs and first and second side wall portions formed in a manner of blocking both ends of the cylindrical portion. The first and second sun gears are arranged axially side by side between the first side wall portion and the second side wall portion. Washers are arranged between the first sun gear and the first side wall portion, between the second sun gear and the second side wall portion, and between the first sun gear and the second sun gear, respectively.

[0004] The first and second sun gears are divided into an outer portion and an inner portion at their radially approximate center portions, and a spline portion formed on the outer periphery of the inner portion is spline-engaged with a spline hole formed on the inner periphery of the outer portion. Through the spline engagement, when torque is transmitted to the left and right wheels, thrusts in opposite directions are generated between the outer portion and the inner portion, and the axial end faces of the outer portion and the inner portion are pressed against the washer. In addition, the differential limiting force is increased by the friction between the axial end faces and the washer.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-174577 Summary of the invention

[0008] Problems to be solved by the invention

[0009] For example, when driving under conditions where a large differential limiting force is frequently generated, such as when driving uphill on a muddy road or a gravel road, there is a situation in which each gear in the differential case expands due to frictional heat and the axial length becomes longer. In such a case, if the axial end faces of any gear in the differential case are pressed against the washer due to the thermal expansion of the gear, the differential limiting force may be larger than the magnitude generated by the axial thrust. In addition, if the axial clearance (gap) between the gear in the differential case and the washer is increased in order to avoid the increase in thrust caused by the thermal expansion of the gear, the responsiveness of the differential limiting force when the wheel slips or the like may decrease.

[0010] Therefore, an object of the present invention is to provide a vehicle differential device capable of suppressing a decrease in the responsiveness of the differential limiting force and suppressing an increase in the differential limiting force caused by thermal expansion of gears in a differential case.

[0011] Means for solving problems

[0012] In order to achieve the above-mentioned object, the present invention provides a vehicle differential device, comprising: a pinion gear set formed by meshing a first pinion gear and a second pinion gear with each other, the first pinion gear and the second pinion gear having helical teeth with tooth lines inclined relative to an axial direction; a first side shaft gear set having a cylindrical first outer gear member meshing with the first pinion gear and a first inner gear member arranged on the inner side of the first outer gear member, the first outer gear member and the first inner gear member being helically splined; a second side shaft gear set having a cylindrical second outer gear member meshing with the second pinion gear and a second inner gear member arranged on the inner side of the second outer gear member, the second outer gear member and the second inner gear member being helically splined. The gears are engaged with each other in a spiral spline; a differential case having a cylindrical portion, a first side wall portion and a second side wall portion, the cylindrical portion being formed with a retaining hole, which accommodates the first pinion and the second pinion so that they can rotate; a first sliding member being arranged between the first half-shaft gear set and the first side wall portion; a second sliding member being arranged between the second half-shaft gear set and the second side wall portion; a third sliding member being arranged between the first half-shaft gear set and the second half-shaft gear set; and an elastic member being arranged in parallel with any one of the first sliding member to the third sliding member in the direction of the rotation axis of the differential case between the first side wall portion and the second side wall portion in the differential case, and being capable of elastic deformation in the direction of the rotation axis.

[0013] Effects of the Invention

[0014] According to the vehicle differential device of the present invention, it is possible to suppress a decrease in the responsiveness of the differential limiting force and also suppress an increase in the differential limiting force caused by thermal expansion of the gears in the differential case. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view showing a configuration example of a vehicle differential device according to the first embodiment of the present invention.

[0016] Figure 2 yes Figure 1 AA line section view.

[0017] Figure 3 This is an exploded perspective view of a vehicle differential device.

[0018] Figure 4A It is a cross-sectional view of a part of the vehicle differential device during driving at normal temperature.

[0019] Figure 4B This is a cross-sectional view of a portion of a vehicle differential device during driving at a high temperature.

[0020] Figure 5A It is a cross-sectional view of a part of the vehicle differential device during coasting at normal temperature.

[0021] Figure 5B It is a cross-sectional view of a part of the differential device for a vehicle during coasting at high temperature.

[0022] Fig. 6A It is a cross-sectional view of a part of a vehicle differential device according to a comparative example during driving at normal temperature.

[0023] Figure 6B It is a cross-sectional view of a part of a vehicle differential device according to a comparative example during high-temperature driving.

[0024] Figure 7 It is a cross-sectional view of a vehicle differential device according to a second embodiment.

[0025] Fig. 8A It is a cross-sectional view of a part of the vehicle differential device according to the second embodiment during driving at normal temperature.

[0026] Figure 8B It is a cross-sectional view of a part of the vehicle differential device according to the second embodiment during high temperature driving. DETAILED DESCRIPTION

[0027] [First embodiment]

[0028] The first embodiment of the present invention is described with reference to the accompanying drawings. It should be noted that the embodiments described below are shown as suitable specific examples when implementing the present invention, and there are also parts that specifically illustrate various technical matters that are technically preferred, but the technical scope of the present invention is not limited to this specific solution.

[0029] Figure 1 It is a cross-sectional view showing a configuration example of the vehicle differential device 1 according to the first embodiment of the present invention. Figure 2 yes Figure 1 AA line section view. Figure 3 FIG. 1 is an exploded perspective view of the vehicle differential device 1. Figure 1 , along the rotation axis of the vehicle differential device 1, Figure 2 Cross section at line BB.

[0030] The vehicle differential device 1 is used to distribute the driving force of the driving source of the vehicle to a pair of output shafts in a differential-allowing manner. As the driving source, an engine or an electric motor can be used. The vehicle differential device 1 of this embodiment is used as a differential device that distributes the driving force of the driving source to the left and right driving wheels, and distributes the input driving force to the left and right driving shafts as a pair of output shafts.

[0031] The vehicle differential device 1 includes a differential case 10 for inputting a driving force from a driving source, a plurality of pinion gear sets 2 retained in the differential case 10, a first and a second half-shaft gear sets 3 and 4 arranged on the inner sides of the plurality of pinion gear sets 2 in the differential case 10, a first end face washer 51 as a first sliding member, a second end face washer 52 as a second sliding member, a center washer 53 as a third sliding member, and a first and a second disc spring 61 and 62 as elastic members.

[0032] The differential case 10 includes a bottomed cylindrical differential case body 11 and a differential case cover 12 arranged to block the opening of the differential case body 11. The differential case body 11 integrally includes a cylindrical cylinder portion 110, a first side wall portion 111 formed to block the end of one side of the axial direction of the cylinder portion 110, a cylindrical extension portion 112 extending outward from the center of the first side wall portion 111, and a flange portion 113 formed to extend outward from the outer peripheral surface of the cylinder portion 110. A ring gear (not shown) is fixed to the flange portion 113, and the driving force of the driving source is transmitted from the ring gear to the differential case 10. The differential case 10 rotates around the rotation axis O by the input driving force. Hereinafter, the direction parallel to the rotation axis O is referred to as the rotation axis direction.

[0033] The differential case cover 12 integrally includes a disc-shaped second side wall portion 121 and a cylindrical extension portion 122 extending outward from the center of the second side wall portion 121. The outer peripheral end of the second side wall portion 121 is fixed to the end of the cylindrical portion 110 of the differential case body 11 on the opposite side of the first side wall portion 111, for example, by welding.

[0034] exist Figure 1 , the first and second bearings 71 and 72 supporting the differential case 10 are shown by imaginary lines (two-dot chain lines). The differential case 10 is supported by the first bearing 71 externally fitted in the extension portion 112 of the differential case body 11 and the second bearing 72 externally fitted in the extension portion 122 of the differential case cover 12 so as to be rotatable relative to the differential carrier (not shown). The first bearing 71 and the second bearing 72 are tapered roller bearings, and axial preload is applied.

[0035] In this embodiment, if Figure 2 As shown, the four pinion gear sets 2 are respectively held in the holding holes 100 formed in the cylindrical portion 110 of the differential case 10. Each pinion gear set 2 has a first pinion gear 21 and a second pinion gear 22, and the first pinion gear 21 and the second pinion gear 22 are meshed with each other. The holding hole 100 has a first hole portion 101 for holding the first pinion gear 21 and a second hole portion 102 for holding the second pinion gear 22, and the first hole portion 101 and the second hole portion 102 are connected. The first hole portion 101 and the second hole portion 102 are open toward the inner side of the cylindrical portion 110.

[0036] The first pinion gear 21 integrally includes a long gear portion 211 and a short gear portion 212 having different lengths in the axial direction, and a connecting portion 213 connecting the long gear portion 211 and the short gear portion 212 in the axial direction. A plurality of helical teeth 211a and 212a whose tooth lines are inclined relative to the axial direction are formed on the outer peripheries of the long gear portion 211 and the short gear portion 212, respectively. Similarly, the second pinion gear 22 integrally includes a long gear portion 221 and a short gear portion 222 having different lengths in the axial direction, and a connecting portion 223 connecting the long gear portion 221 and the short gear portion 222 in the axial direction. A plurality of helical teeth 221a and 222a whose tooth lines are inclined relative to the axial direction are formed on the outer peripheries of the long gear portion 221 and the short gear portion 222, respectively.

[0037] The short gear portion 212 of the first pinion gear 21 meshes with a portion of the long gear portion 221 of the second pinion gear 22. In addition, the short gear portion 222 of the second pinion gear 22 meshes with a portion of the long gear portion 211 of the first pinion gear 21.

[0038] The first side gear set 3 includes a cylindrical first outer gear member 31 meshing with the first pinion gear 21, and a first inner gear member 32 disposed inside the first outer gear member 31. The first outer gear member 31 meshes with a portion of the long gear portion 211 of the first pinion gear 21. A plurality of helical teeth 31a inclined with respect to the axial direction are formed on the outer periphery of the first outer gear member 31, and the helical teeth 31a mesh with the helical teeth 211a of the long gear portion 211 of the first pinion gear 21. That is, the long gear portion 211 of the first pinion gear 21 meshes with the short gear portion 222 of the second pinion gear 22 at a portion, and meshes with the first outer gear member 31 at another portion.

[0039] The first outer gear member 31 and the first inner gear member 32 are helical splined. The inner periphery of the first outer gear member 31 is formed with helical spline teeth 31b inclined relative to the axial direction, and the helical spline teeth 31b mesh with the helical spline teeth 32a formed on the outer periphery of the first inner gear member 32. The inner periphery of the first inner gear member 32 is formed with a straight splined fitting portion 320 composed of a plurality of spline teeth 32b extending parallel to the rotation axis O. One end portion of a drive shaft that transmits a driving force to, for example, the left front wheel of a vehicle is connected to the straight splined fitting portion 320 in a relatively non-rotatable manner.

[0040] The second side gear set 4 includes a cylindrical second outer gear member 41 meshing with the second pinion gear 22 and a second inner gear member 42 disposed inside the second outer gear member 41. The second outer gear member 41 meshes with a portion of the long gear portion 221 of the second pinion gear 22. A plurality of helical teeth 41a inclined with respect to the axial direction are formed on the outer periphery of the second outer gear member 41, and the helical teeth 41a mesh with the helical teeth 221a of the long gear portion 221 of the second pinion gear 22. That is, the long gear portion 221 of the second pinion gear 22 meshes with the short gear portion 212 of the first pinion gear 21 at a portion thereof, and meshes with the second outer gear member 41 at another portion thereof.

[0041] The second outer gear member 41 and the second inner gear member 42 are helical splined. Helical spline teeth 41b inclined relative to the axial direction are formed on the inner periphery of the second outer gear member 41, and the helical spline teeth 41b mesh with helical spline teeth 42a formed on the outer periphery of the second inner gear member 42. A straight splined fitting portion 420 composed of a plurality of spline teeth 42b extending parallel to the rotation axis O is formed on the inner periphery of the second inner gear member 42. One end portion of a drive shaft that transmits a driving force to, for example, the right front wheel of a vehicle is connected to the straight splined fitting portion 420 in a relatively non-rotatable manner.

[0042] The first end face washer 51, the second end face washer 52, and the center washer 53 are flat plate-shaped metal members having a predetermined thickness in the rotation axis direction of the differential case 10. The first end face washer 51 is arranged between the first side gear set 3 and the first side wall portion 111 of the differential case 10. The second end face washer 52 is arranged between the second side gear set 4 and the second side wall portion 121 of the differential case 10. The center washer 53 is arranged between the first side gear set 3 and the second side gear set 4.

[0043] The first end face washer 51 is housed in a recessed portion 111a formed in the first side wall portion 111 of the differential case 10, and is relatively movable in the rotation axis direction relative to the differential case 10 in the recessed portion 111a. The first end face washer 51 integrally includes an annular main body portion 510 and a plurality of protrusions 511 formed so as to protrude outward from the main body portion 510. A portion of the recessed portion 111a serves as a rotation stop portion 111b formed so as to protrude outwardly, and the relative rotation of the first end face washer 51 relative to the differential case 10 is restricted by the protrusions 511 being fitted into the rotation stop portion 111b.

[0044] The second end face washer 52 is housed in a recessed portion 121a formed in the second side wall portion 121 of the differential case 10, and is relatively movable in the rotation axis direction relative to the differential case 10 in the recessed portion 111a. The second end face washer 52 integrally includes an annular main body portion 520 and a plurality of protrusions 521 formed so as to protrude outward from the main body portion 520. A portion of the recessed portion 121a serves as a rotation stop portion 121b formed so as to protrude outward, and the relative rotation of the second end face washer 52 relative to the differential case 10 is restricted by the protrusions 521 being fitted into the rotation stop portion 121b.

[0045] The center washer 53 has an annular main body 530 and a plurality of protrusions 531 formed to protrude outward from the main body 530. The plurality of protrusions 531 are engaged between the connecting portions 213 and 223 of the first and second pinion gears 21 and 22, respectively, so that the relative rotation of the center washer 53 with respect to the differential case 10 is restricted, and the center washer 53 can move relative to the differential case 10 in the direction of the rotation axis.

[0046] Figure 4A and Figure 4B It is a cross-sectional view showing the first side wall portion 111 and the second side wall portion 121 when the torque in the forward direction of the vehicle is input to the differential case 10 of the vehicle differential device 1 (when driving), the first and second half-shaft gear sets 3, 4 arranged between the first side wall portion 111 and the second side wall portion 121, the first and second end washers 51, 52, the center washer 53 and the first and second disc springs 61, 62.

[0047] Figure 4AThe first outer gear member 31 and the first inner gear member 32 of the first side gear set 3 and the second outer gear member 41 and the second inner gear member 42 of the second side gear set 4 are shown to be at room temperature. Figure 4B The first outer gear member 31 and the first inner gear member 32 of the first side gear set 3, and the second outer gear member 41 and the second inner gear member 42 of the second side gear set 4 are thermally expanded and their axial lengths are longer than those at room temperature. Figure 4A and Figure 4B and the following Figure 5A and Figure 5B , Fig. 6A and Figure 6B , Fig. 8A and Figure 8B In order to make the description clear, the thermal expansion amount of each gear member is exaggerated in the figure.

[0048] One surface of the first end face washer 51 in the rotation axis direction of the differential case 10 is a sliding surface 51a that frictionally slides with respect to the axial end surface 31c on the first side wall portion 111 side of the first outer gear member 31 and the axial end surface 32c on the first side wall portion 111 side of the first inner gear member 32. The other surface of the first end face washer 51 in the rotation axis direction of the differential case 10, which corresponds to the back surface of the sliding surface 51a, is a contact surface 51b that contacts the first disc spring 61. The first disc spring 61 is arranged between the contact surface 51b of the first end face washer 51 and the first side wall portion 111.

[0049] The first disc spring 61 is accommodated in the recess 111a of the first side wall portion 111 together with the first end face washer 51, and is arranged adjacent to the first end face washer 51 in the rotation axis direction of the differential case 10. The first disc spring 61 can be elastically deformed in the rotation axis direction of the differential case 10, and one end 611 in the rotation axis direction abuts against the abutment surface 51b of the first end face washer 51, and the other end 612 in the rotation axis direction abuts against the bottom surface 111c of the recess 111a. The first end face washer 51 is pressed toward the first side gear set 3 in the rotation axis direction of the differential case 10 by the restoring force of the first disc spring 61.

[0050] One surface of the second end face washer 52 in the rotation axis direction of the differential case 10 is a sliding surface 52a that performs frictional sliding with respect to the axial end surface 41c on the first side wall portion 111 side of the second outer gear member 41 and the axial end surface 42c on the second side wall portion 121 side of the second inner gear member 42. The other surface of the second end face washer 52 in the rotation axis direction of the differential case 10, which corresponds to the back surface of the sliding surface 52a, is a contact surface 52b that contacts the second disc spring 62. The second disc spring 62 is arranged between the contact surface 52b of the second end face washer 52 and the second side wall portion 121.

[0051] The second disc spring 62 is accommodated in the recess 121a of the second side wall portion 121 together with the second end face washer 52, and is arranged adjacent to the second end face washer 52 in the rotation axis direction of the differential case 10. The second disc spring 62 can be elastically deformed in the rotation axis direction of the differential case 10, and one end 621 in the rotation axis direction abuts against the abutment surface 52b of the second end face washer 52, and the other end 622 in the rotation axis direction abuts against the bottom surface 121c of the recess 121a. The second end face washer 52 is pressed toward the second side gear set 4 in the rotation axis direction of the differential case 10 by the restoring force of the second disc spring 62.

[0052] exist Figure 4A and Figure 4B In F 11 、F 12 、F 13 、F 21 、F 22 、F 23 The arrows indicate thrust in the rotation axis direction of the differential case 10 received by the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42 when the vehicle differential device 1 transmits torque. The direction of each arrow indicates the direction of the thrust.

[0053] F 11 F is the thrust force received by the first outer gear member 31 due to meshing with the first pinion gear 21. 12 F is the thrust force received by the first outer gear member 31 due to the helical spline engagement with the first inner gear member 32. 13 As F 12 The reaction force is the thrust received by the first inner gear member 32 due to the helical spline engagement with the first outer gear member 31 .

[0054] F 21 F is the thrust force received by the second outer gear member 41 due to meshing with the second pinion gear 22. 22 F is the thrust force received by the second outer gear member 41 due to the helical spline engagement with the second inner gear member 42. 23 As F 22 The reaction force is the thrust received by the second inner gear member 42 due to the helical spline engagement with the second outer gear member 41 .

[0055] The axial end surface 31d of the first outer gear member 31 on the center washer 53 side is pushed by the thrust F 11 and F 12The first sliding surface 53a of the first inner gear member 32 is pressed against the first sliding surface 53a of the center washer 53, and receives friction resistance from the center washer 53. The axial end surface 32c of the first inner gear member 32 on the first side wall portion 111 side is thrusted by the thrust F 13 The sliding surface 51 a is pressed against the first end surface washer 51 , and receives frictional resistance from the first end surface washer 51 .

[0056] The axial end surface 41d of the second outer gear member 41 on the center washer 53 side is pushed by the thrust F 21 and F 22 The second sliding surface 53b is pressed against the center washer 53, and receives frictional resistance from the center washer 53. The axial end surface 42c on the second side wall portion 121 side of the second inner gear member 42 is pushed by the thrust F 23 The sliding surface 52 a is pressed against the second end surface washer 52 , and receives frictional resistance from the second end surface washer 52 .

[0057] The friction resistances received by the first outer gear member 31 and the second outer gear member 41 from the center washer 53, the friction resistance received by the first inner gear member 32 from the first end washer 51, and the friction resistance received by the second inner gear member 42 from the second end washer 52 serve as differential limiting forces for limiting the differential rotation of the left and right wheels during driving.

[0058] Figure 5A and Figure 5B It is a cross-sectional view showing the first side wall portion 111, the second side wall portion 121, the first and second side gear sets 3, 4, the first and second end washers 51, 52, the center washer 53, and the first and second disc springs 61, 62 when the torque is transmitted from the left and right wheels to the differential case 10 during the forward inertial driving of the vehicle (during coasting). Figure 5A In the figure, the gear components are shown to be at room temperature. Figure 5B , a state is shown in which each gear member thermally expands and the axial length thereof becomes longer than that at room temperature.

[0059] During coasting, a thrust in the opposite direction to that during driving is applied to the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42. Figure 5A and Figure 5B In the -F 11 , -F 12 , -F 13 , -F 21 , -F 22 , -F 23 The arrows show these thrusts.

[0060] By these thrusts, the axial end face 31c on the first side wall portion 111 side of the first outer gear member 31 is pressed against the sliding face 51a of the first end face washer 51, and the axial end face 32d on the center washer 53 side of the first inner gear member 32 is pressed against the first sliding face 53a of the center washer 53. In addition, the axial end face 41c on the second side wall portion 121 side of the second outer gear member 41 is pressed against the sliding face 52a of the second end face washer 52, and the axial end face 42d on the center washer 53 side of the second inner gear member 42 is pressed against the second sliding face 53b of the center washer 53. The frictional resistance thus generated becomes a differential limiting force that limits the differential rotation of the left and right wheels during sliding.

[0061] The first disc spring 61 is pushed by the force F during driving. 13 Compressed in the axial direction, and also thrust during sliding - F 11 and -F 12 The first end washer 51 is compressed in the axial direction. As the first disc spring 61 is compressed, the first end washer 51 is displaced toward the bottom surface 111c of the recessed portion 111a of the first side wall portion 111. Figure 4A At room temperature, Figure 4B At high temperatures as shown, the axial end face 31c of the first outer gear member 31 does not contact the sliding face 51a of the first end face washer 51, and the axial end face 32d of the first inner gear member 32 does not contact the first sliding face 53a of the center washer 53. Figure 5A At room temperature, Figure 5B At the high temperature shown, the axial end surface 31 d of the first outer gear member 31 does not contact the first sliding surface 53 a of the center washer 53 , and the axial end surface 32 c of the first inner gear member 32 does not contact the sliding surface 51 a of the first end surface washer 51 .

[0062] The second disc spring 62 is pushed by the force F during driving. 23 Compressed in the axial direction, and also thrust during sliding - F 21 and -F 22 The second end washer 52 is compressed in the axial direction. As the second disc spring 62 is compressed, the second end washer 52 is displaced toward the bottom surface 121c of the recessed portion 121a of the second side wall portion 121. Figure 4A At room temperature, Figure 4B At high temperatures as shown, the axial end face 41c of the second outer gear member 41 does not contact the sliding face 52a of the second end face washer 52, and the axial end face 42d of the second inner gear member 42 does not contact the second sliding face 53b of the center washer 53. Figure 5A At room temperature, Figure 5BAt the high temperature shown, the axial end surface 41 d of the second outer gear member 41 does not contact the second sliding surface 53 b of the center washer 53 , and the axial end surface 42 c of the second inner gear member 42 does not contact the sliding surface 52 a of the second end washer 52 .

[0063] Thus, in the present embodiment, even if the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42 are thermally expanded, the first disc spring 61 and the second disc spring 62 will absorb the thermal expansion, and the axial end faces of these gear members will not simultaneously contact the center washer 53 and the first end face washer 51 or the second end face washer 52. Therefore, the increase in the differential limiting force caused by the thermal expansion of these gear members can be suppressed.

[0064] In addition, even if the axial depth of the recessed portions 111a and 121a is increased and the axially movable stroke distance of the first end face washer 51 and the second end face washer 52 is extended in order to absorb the thermal expansion, the first end face washer 51 and the second end face washer 52 are respectively urged in the direction of the rotation axis of the differential case 10 by the first disc spring 61 and the second disc spring 62, so that the responsiveness of the differential limiting force can be prevented from decreasing. That is, according to the present embodiment, the increase of the differential limiting force caused by the thermal expansion of the gears in the differential case can be suppressed while suppressing the decrease in the responsiveness of the differential limiting force.

[0065] [Comparative Example]

[0066] Fig. 6A and Figure 6B It is a cross-sectional view showing the structure of a vehicle differential device that does not include the first disc spring 61 and the second disc spring 62 as a comparative example. Fig. 6A It shows the driving status at normal temperature. Figure 6B The state during driving at high temperature is shown.

[0067] In this comparative example, if the first outer gear member 31 and the second outer gear member 41 become hot and expand thermally so that the axial length increases, Figure 6B As shown, the axial end faces 31c and 31d of the first outer gear member 31 abut against the first end face washer 51 and the center washer 53, and the axial end faces 41c and 41d of the second outer gear member 41 abut against the second end face washer 52 and the center washer 53. If the gaps between the first outer gear member 31 and the second outer gear member 41 and the washers 51 to 53 between the first side wall portion 111 and the second side wall portion 121 are filled in this way, the friction force between them increases, and the differential limiting force increases sharply.

[0068] In addition, if the first inner gear member 32 and the second inner gear member 42 expand thermally and their axial lengths increase, Figure 6B As shown, the axial end faces 32c and 32d of the first inner gear member 32 abut against the first end face washer 51 and the center washer 53, and the axial end faces 42c and 42d of the second inner gear member 42 abut against the second end face washer 52 and the center washer 53. If the gaps between the first inner gear member 32 and the second inner gear member 42 and the washers 51 to 53 between the first side wall portion 111 and the second side wall portion 121 are filled in this way, the friction force between them increases, and the differential limiting force increases sharply.

[0069] Furthermore, when the gaps between the gear components and the washers 51 to 53 are increased in such a manner that the gaps between the gear components and the washers 51 to 53 are not filled even when the gear components thermally expand, the axial movement of the gear components until frictional force is generated becomes longer, and the responsiveness of the differential limiting force decreases.

[0070] In contrast, according to the first embodiment described above, a gap in the rotation axis direction of the differential case 10 is formed between the bottom surface 111c of the recessed portion 111a of the first side wall portion 111 and the bottom surface 121c of the recessed portion 121a of the second side wall portion 121, and at least a portion between the first disc spring 61, the first end face washer 51, the first outer gear member 31 and the first inner gear member 32, the center washer 53, the second outer gear member 41 and the second inner gear member 42, the second end face washer 52, and the second disc spring 62. That is, the thermal expansion of the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42 can be absorbed by the first disc spring 61 and the second disc spring 62, and the gap between the first side wall portion 111 and the second side wall portion 121 is not completely filled, so that the differential limiting force can be suppressed from increasing due to the thermal expansion of the gears in the differential case while suppressing a decrease in the responsiveness of the differential limiting force.

[0071] It should be noted that, even in the case where the axial end faces 31c and 31d of the first outer gear member 31 are in contact with both the first end face washer 51 and the center washer 53, or the axial end faces 32c and 32d of the first inner gear member 32 are in contact with both the first end face washer 51 and the center washer 53, as long as a space having a length in the rotation axis direction equal to the thickness T of the first disc spring 61 (see FIG. 1 ) is formed between the bottom face 111c of the recessed portion 111a of the first side wall portion 111 and the first end face washer 51, the first disc spring 61 can be prevented from being damaged. Figure 4A ) or more, the above-mentioned effect can be obtained. The same is true for the second side gear 4.

[0072] [Second embodiment]

[0073] Next, refer to Figure 7 and Fig. 8A and Figure 8B A second embodiment of the present invention will be described.

[0074] Figure 7 It is a cross-sectional view of a vehicle differential device 1A according to a second embodiment. Fig. 8A It is a cross-sectional view of a part of the vehicle differential device 1A at normal temperature. Figure 8B It is a cross-sectional view of a part of the vehicle differential device 1A at a high temperature.

[0075] In the first embodiment, the first disc spring 61 is arranged between the first end washer 51 and the first side wall portion 111, the second disc spring 62 is arranged between the second end washer 52 and the second side wall portion 121, and one center washer 53 is arranged between the first side gear set 3 and the second side gear set 4. In the vehicle differential device 1A of the second embodiment, no elastic member such as a disc spring is arranged between the first end washer 51 and the first side wall portion 111 and between the second end washer 52 and the second side wall portion 121, and two center washers 54 and 55 as third sliding members are arranged between the first side gear set 3 and the second side gear set 4 instead of the center washers 53, and the disc spring 63 as an elastic member is arranged between these center washers 54 and 55. The other structures of the vehicle differential device 1A are the same as those of the vehicle differential device 1 of the first embodiment.

[0076] Hereinafter, the central washer 54 on the first side gear set 3 side of the two central washers 54 and 55 is referred to as the first central washer 54, and the central washer 55 on the second side gear set 4 side is referred to as the second central washer 55. The first central washer 54 includes an annular main body 540 and a plurality of protrusions 541 formed so as to protrude outward from the main body 540. The second central washer 55 includes an annular main body 550 and a plurality of protrusions 551 formed so as to protrude outward from the main body 550. The plurality of protrusions 541 and 551 are engaged with the connecting portions 213 and 223 of the first and second pinion gears 21 and 22, respectively, so that the relative rotation of the first and second central washers 54 and 55 with respect to the differential case 10 is restricted, and the first and second central washers 54 and 55 can move relative to the differential case 10 in the direction of the rotation axis.

[0077] The surface of the first center washer 54 on the side of the first side gear set 3 is a first sliding surface 54a that slides relative to the axial end surface 31d of the first outer gear member 31 during driving and slides relative to the axial end surface 32d of the first inner gear member 32 during coasting. The surface of the second center washer 55 on the side of the second side gear set 4 is a second sliding surface 55a that slides relative to the axial end surface 41d of the second outer gear member 41 during driving and slides relative to the axial end surface 42d of the second inner gear member 42 during coasting.

[0078] The disc spring 63 is arranged with the first center washer 54 and the second center washer 55 in the rotation axis direction of the differential case 10, and is disposed between the first abutting surface 54b on the back side of the first sliding surface 54a of the first center washer 54 and the second abutting surface 55b on the back side of the second sliding surface 55a of the second center washer 55. One end 631 of the disc spring 63 in the rotation axis direction of the differential case 10 abuts against the first abutting surface 54b of the first center washer 54, and the other end 632 of the disc spring 63 in the rotation axis direction of the differential case 10 abuts against the second abutting surface 55b of the second center washer 55.

[0079] The disc spring 63 applies force to the first center washer 54 toward the first side gear set 3, and applies force to the second center washer 55 toward the second side gear set 4. In addition, the disc spring 63 is compressed in the axial direction by the thrust acting on the first outer gear member 31 and the second outer gear member 41 during driving, and is compressed in the axial direction by the thrust acting on the first inner gear member 32 and the second inner gear member 42 during coasting.

[0080] According to the vehicle differential device 1A of the second embodiment, the thermal expansion of the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42 can be absorbed by the disc spring 63 as in the first embodiment, and the interval between the first center washer 54 and the second center washer 55 is maintained at a distance longer than the thickness of the disc spring 63. Thus, the increase in the differential limiting force caused by the thermal expansion of the gears in the differential case can be suppressed while suppressing the decrease in the responsiveness of the differential limiting force.

[0081] (Note)

[0082] The present invention has been described above based on the first and second embodiments, but these embodiments do not limit the invention to which the claims relate. In addition, it should be noted that not all combinations of the features described in the embodiments are necessary for solving the problems of the invention. In addition, the present invention can omit a part of the structure or add or replace the structure within the scope of its main purpose, and can be appropriately deformed and implemented. Moreover, it is also possible to combine part of the structures of the above-mentioned multiple embodiments with each other, and it is also possible to deform, for example, as follows.

[0083] In the first embodiment described above, the first disc spring 61 is arranged between the first end face washer 51 and the first side wall portion 111, and the second disc spring 62 is arranged between the second end face washer 52 and the second side wall portion 121. However, one of the first disc spring 61 and the second disc spring 62 may be omitted. For example, when the first disc spring 61 is omitted, the first end face washer 51 abuts against the bottom surface 111c of the recessed portion 111a of the first side wall portion 111, and the second disc spring 62 absorbs the thermal expansion of the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42. In addition, when the second disc spring 62 is omitted, the second end face washer 52 abuts against the bottom surface 121c of the recessed portion 121a of the second side wall portion 121, and the first disc spring 61 absorbs the thermal expansion of the first outer gear member 31, the first inner gear member 32, the second outer gear member 41, and the second inner gear member 42. That is, as long as at least one of the first disc spring 61 and the second disc spring 62 of the first embodiment and the disc spring 63 of the second embodiment is used as an elastic member, the effect of the present invention can be obtained. It should be noted that the elastic member is not limited to the disc spring, and for example, a wave washer, a coil spring, etc. can be used.

[0084] In addition, in the first and second embodiments, the case where each pinion gear set 2 is composed of a combination of two pinions (the first pinion gear 21 and the second pinion gear 22) of the same axial length is described, but it is not limited to this. For example, as proposed by the applicant in Japanese Patent Publication No. 2020-94681, a pinion gear set can be formed by combining a pinion gear and two pinions shorter than the pinion gear. In this case, as a pinion gear, a pinion gear having two gear portions of different pitch circle diameters on one side and the other side of the central portion in the longitudinal direction is used, so that the two pinions with shorter lengths are meshed with the gear portion of the smaller diameter.

[0085] Description of symbols

[0086] 1.1A…Differential device for vehicles

[0087] 10…Differential case

[0088] 100…Holding hole

[0089] 110…Cylinder

[0090] 111 ...first side wall portion

[0091] 2…Pinion gear set

[0092] 21…First pinion

[0093] 22…Second pinion

[0094] 3…First half shaft gear set

[0095] 31 ... first outer gear member

[0096] 32 ... first inner gear member

[0097] 4…Second axle gear set

[0098] 41 ... second outer gear member

[0099] 42 ... second inner gear member

[0100] 51 ... first end surface washer (first sliding member)

[0101] 52 ... second end face washer (second sliding member)

[0102] 53 ...Central washer (third sliding member)

[0103] 54 ... first central washer (third sliding member)

[0104] 55...Second central washer (third sliding member)

[0105] 61…first disc spring (elastic member)

[0106] 62…first disc spring (elastic member)

[0107] 63…first disc spring (elastic member)

Claims

1. A vehicle differential device, comprising: A pinion gear set formed by meshing a first pinion gear and a second pinion gear with each other, wherein the first pinion gear and the second pinion gear have helical teeth whose tooth lines are inclined relative to an axial direction; A first side gear set includes a cylindrical first outer gear member meshing with the first pinion gear and a first inner gear member disposed inside the first outer gear member, wherein the first outer gear member and the first inner gear member are helical spline-engaged; a second side gear set including a cylindrical second outer gear member meshing with the second pinion gear and a second inner gear member disposed inside the second outer gear member, wherein the second outer gear member and the second inner gear member are helical spline-engaged; A differential case having a cylindrical portion, a first side wall portion, and a second side wall portion, wherein the cylindrical portion is formed with a retaining hole, and the retaining hole accommodates the first pinion gear and the second pinion gear so as to be rotatable; A first sliding member, disposed between the first side shaft gear set and the first side wall portion; A second sliding member is disposed between the second side shaft gear set and the second side wall portion; a third sliding member, disposed between the first side shaft gear set and the second side shaft gear set; as well as The elastic member is arranged between the first side wall portion and the second side wall portion in the differential case in parallel with any one of the first to third sliding members in the rotation axis direction of the differential case and is elastically deformable in the rotation axis direction.

2. The vehicle differential device according to claim 1, wherein: One surface of the first sliding member in the rotation axis direction is a sliding surface that frictionally slides relative to the axial end surfaces of each of the first outer gear member and the first inner gear member, and the elastic member is arranged between the other surface of the first sliding member in the rotation axis direction and the first side wall portion.

3. The vehicle differential device according to claim 2, wherein: One surface of the second sliding member in the rotation axis direction is a sliding surface that frictionally slides relative to the axial end surfaces of each of the second outer gear member and the second inner gear member, and the elastic member is arranged between the other surface of the second sliding member in the rotation axis direction and the second side wall portion.

4. The vehicle differential device according to claim 3, wherein: The first sliding member and the second sliding member are restricted from rotating relative to the differential case, and are relatively movable relative to the differential case in the rotation axis direction.

5. The vehicle differential device according to any one of claims 1 to 4, wherein: The vehicle differential device includes two third sliding members, and the elastic member is disposed between the two third sliding members.

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