Differential device

Abstract

To provide a differential device capable of dividing the inside of a differential case from the outside thereof in an output gear having a gear member and an output member by using a sealing member.SOLUTION: A differential device 1 includes: a differential case 7 rotatably arranged; a differential gear 11 rotatably supported by the differential case 7 for revolving with the rotation of the differential case 7; and a pair of output gears 13, 15 engaging with the differential gears 11 and relatively rotatable. The output gears 13, 15 each have: a gear member 37 engaging with the differential gear 11; and an output member 39 arranged on an inner diameter side of the gear member 37 via an engagement part 57 so as to be integrally rotatable with the gear member 37. At an end of the output member 39, a sealing member 63 is arranged for dividing the inside of the differential case 7 from the outside thereof.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, a differential device includes a rotatably arranged differential case, a differential gear supported by the differential case so as to be rotatable about its axis and revolving with the rotation of the differential case, a pair of output gears meshing with the differential gear and rotatable relative to each other, and a pair of output shafts connected to the inner diameter sides of the pair of output gears so as to be rotatable together with the differential case (see Patent Document 1).

[0003] In this differential device, a cap member is disposed on the output gear as a sealing member that separates the inside and outside of the differential case. The cap member separates the inside and outside of the differential case and prevents oil flowing through the inside of the differential case from leaking to the outside from the pair of output shafts.

[0004] Meanwhile, another differential device is known in which the output gear has a gear member and an output member (see Patent Document 2). In this differential device, the gear member meshes with the differential gear. The output member is disposed on the inner diameter side of the gear member via a cam portion as an engagement portion so as to be integrally rotatable with the gear member, and an output shaft is connected to the inner diameter side so as to be integrally rotatable with the gear member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-166625 A [Patent Document 2] JP 2019-124264 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the differential device of the above-mentioned Patent Document 2, the output gear is composed of two members, a gear member and an output member, and a gap exists between the gear member and the output member. Assume that the sealing member of Patent Document 1, which separates the inside and outside of the differential case, is disposed on the end of such an output gear. However, if the sealing member of Patent Document 1 is simply disposed on the end of the output gear, the gap between the gear member and the output member will communicate with the output shaft side, and it will not be possible to separate the inside and outside of the differential case.

[0007] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a differential device in which the inside and outside of a differential case can be separated by a sealing member in an output gear having a gear member and an output member. [Means for solving the problem]

[0008] The differential device of this embodiment comprises a rotatably arranged differential case, a differential gear supported rotatably on the differential case and revolving with the rotation of the differential case, and a pair of output gears that mesh with the differential gear and can rotate relatively, the output gear has a gear member that meshes with the differential gear, and an output member that is arranged on the inner diameter side of the gear member so as to be rotatable together with the gear member via an engagement portion, and a sealing member that separates the inside and outside of the differential case is arranged at the end of the output member. Effect of the Invention

[0009] According to the present invention, it is possible to provide a differential device in which the inside and outside of a differential case can be separated by a sealing member in an output gear having a gear member and an output member. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view of the differential device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The differential device according to the present embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0012] 1, a differential device 1 according to this embodiment is disposed between a drive source (not shown), such as an engine or an electric motor, and left and right wheels (not shown). Driving force from the drive source is transmitted to the differential device 1 via a transmission (not shown), and the driving force is distributed to the left and right wheels via a pair of output shafts (not shown).

[0013] As shown in FIG. 1, the differential device 1 includes a differential mechanism 3 and a differential limiting unit 5.

[0014] The differential mechanism 3 includes a differential case 7, a pinion shaft 9, a differential gear 11, and a pair of output gears 13 and 15.

[0015] The differential case 7 is rotatably supported by a casing 25 via bearings 21, 23 at the outer peripheries of bosses 17, 19 formed on both axial sides. The casing 25 contains lubricating oil for lubricating and cooling the sliding parts and meshing parts on the outside of the differential case 7 and the sliding parts and meshing parts inside the differential case 7. Seal members 27, 29 that separate the inside and outside of the casing 25 are arranged radially between the casing 25 and the pair of output gears 13, 15.

[0016] A flange portion 31 to which a ring gear (not shown) is fixed is formed on the differential case 7. The ring gear fixed to the flange portion 31 meshes with a power transmission gear (not shown) that transmits driving force, and the driving force is transmitted to rotate the differential case 7. A pinion shaft 9, a differential gear 11, a pair of output gears 13, 15, etc. are housed and arranged inside the differential case 7.

[0017] The pinion shaft 9 has an end that engages with a hole formed in the differential case 7 and is prevented from slipping out and rotating by a pin 33, and is rotated integrally with the differential case 7. The pinion shaft 9 is housed in a thrust block 35 that determines the axial position of a pair of output gears 13, 15 so that both axial ends are exposed to the outside. Differential gears 11 are supported on both axial ends of the pinion shaft 9, respectively.

[0018] A plurality of differential gears 11 (two in this example) are arranged at equal intervals in the circumferential direction of the differential case 7, each supported on the shaft end side of the pinion shaft 9 and revolving with the rotation of the differential case 7. The differential gear 11 transmits driving force to the pair of output gears 13, 15, and is rotatably supported by the pinion shaft 9 so as to be rotationally driven when a differential rotation occurs between the pair of meshed output gears 13, 15.

[0019] The pair of output gears 13, 15 are accommodated in the differential case 7 so as to be capable of relative rotation. Each of the pair of output gears 13, 15 includes a gear member 37 and an output member 39. In the pair of output gears 13, 15, the gear member 37 and the output member 39 are formed symmetrically, so that only one of them will be mainly described below, and a description of the other will be omitted.

[0020] The gear member 37 is formed in an annular shape, and a gear portion that meshes with the differential gear 11 is formed on the outer periphery of the gear member 37. The gear member 37 meshes with the differential gear 11, thereby transmitting driving force from the differential gear 11 to the pair of output gears 13, 15. In addition, when a differential rotation occurs between the pair of output gears 13, 15, the gear member 37 rotates the differential gear 11.

[0021] The output member 39 is formed in a concave ring shape so that one axial end side (axial inner side) can be arranged close to the gear member 37 in the axial direction and can accommodate a part of the gear member 37 in the axial direction. The concave ring part of the output member 39 is a cylindrical gear support part 41 that supports the gear member 37 in the radial direction. The axial end of the gear support part 41 is a cylindrical seal support part 43 on whose inner diameter side a seal member 63 described later is arranged. By providing the seal support part 43 on the inner diameter side of the gear support part 41, the gear support part 41 and the seal support part 43 are arranged overlapping each other in the radial direction, and the output member 39 can be prevented from becoming large in the axial direction. The axial length of the gear support part 41 is set to be longer than the axial length of the seal support part 43. Therefore, the gear member 37 can be supported in the radial direction by the gear support part 41 over a wide range in the axial direction, and the radial support of the gear member 37 by the gear support part 41 can be stabilized.

[0022] The output member 39 has a sliding surface 45 that is conically inclined in the axial direction at a portion located radially outward of the gear member 37. The output member 39 has, on its inner circumferential side, a pair of output gears 13, 15, spline-shaped output sections 47, 49 that can be connected to a pair of output shafts (not shown) so as to be rotatable together. The output sections 47, 49 each have a fixing section 51 formed of a circumferentially continuous groove that engages with a fixing member such as a C-type washer that fixes the pair of output shafts. The output sections 47, 49 each have a toothless section 53 that has no teeth in a portion of the circumferential direction. The toothless section 53 prevents an increase in internal pressure in the output sections 47, 49 when the pair of output shafts are connected to the output sections 47, 49. A seal groove 55 is provided continuously in the circumferential direction on the other axial end side (axial outer side) of the output member 39. The seal groove 55 is provided with a seal member (not shown) such as an O-ring that prevents a lubricant such as grease applied to the output parts 47, 49 from leaking to the outside. The seal member arranged in the seal groove 55 is in close contact with the outer periphery of a pair of output shafts connected to the output parts 47, 49, facing the outer periphery. The output member 39 outputs the driving force input from the differential case 7 to the pair of output gears 13, 15 to the left and right wheels via the pair of output shafts.

[0023] An engagement portion 57 that converts rotational torque into axial thrust force is provided between the gear member 37 and the output member 39 in the axial direction. The engagement portion 57 is made up of a plurality of engagement recesses provided on the inner peripheral side of the gear member 37 and a plurality of engagement protrusions that are provided on the outer peripheral side of the output member 39 and can engage with the plurality of engagement recesses. The engagement portion 57 enables the gear member 37 and the output member 39 to rotate integrally by engaging the plurality of engagement recesses with the plurality of engagement protrusions.

[0024] The engaging portion 57 is arranged so that at least a part of the axial direction overlaps with the fixed portion 51 in the radial direction. By arranging the engaging portion 57 and the fixed portion 51 so that they overlap with each other in the radial direction, it is possible to secure the rigidity of the transmission path of the driving force while saving space, and to stabilize the transmission of the driving force. The seal support portion 43 is arranged on the inner diameter side of the gear member 37 relative to the engaging portion 57, and is set to have a thin radial thickness. By arranging the seal support portion 43 on the inner diameter side of the gear member 37 relative to the engaging portion 57, even if the thickness of the seal support portion 43 is made thin, the engagement of the engaging portion 57 is not affected. In addition, by setting the thickness of the seal support portion 43 to be thinner than the engaging portion 57, it is possible to secure the arrangement space for the sealing member 63 described later without increasing the size.

[0025] The engagement portion 57 is a cam surface inclined at a predetermined angle in the rotational direction between the multiple engagement recesses and multiple engagement protrusions. When a driving force (driving torque) is input to the differential case 7, the cam surface of the engagement portion 57 is engaged by the driving force branched from the differential gear 11 and input to the pair of output gears 13, 15, and moves the output member 39 axially outward. The axial movement of the output member 39 by the cam surface of the engagement portion 57 can increase and strengthen the differential limiting force in the differential limiting unit 5 arranged between the differential case 7 and the pair of output gears 13, 15.

[0026] The differential limiting portion 5 is disposed between the differential case 7 and the pair of output gears 13, 15. The differential limiting portion 5 has a tapered ring 59 and an output member 39 which slide against each other.

[0027] The tapered rings 59 are disposed at positions on the differential case 7 corresponding to the sliding surfaces 45 of the output members 39 of the pair of output gears 13, 15. The tapered rings 59 rotate integrally with the differential case 7 by engaging multiple protrusions formed in the circumferential direction on the inner peripheral side with recesses formed on the inner wall surface of the differential case 7.

[0028] The tapered ring 59 slides against the sliding surface 45 of the output member 39 of the pair of output gears 13, 15 which is moved axially by a meshing reaction force with the differential gear 11 according to the magnitude of the driving force (driving torque) input to the differential case 7. At this time, the sliding friction between the tapered ring 59 and the sliding surface 45, which is the differential limiting force of the differential limiting unit 5, is increased and strengthened by the cam thrust force of the cam surface of the engagement portion 57.

[0029] The differential limiting unit 5 transmits friction torque between the differential case 7 and the pair of output gears 13, 15 in response to the magnitude of the cam thrust force, thereby limiting the differential of the differential mechanism 3. Such a differential limiting unit 5 is a cone clutch type among torque-sensitive friction clutches. A preload is applied to the differential limiting unit 5 by a biasing member 61.

[0030] The biasing member 61 is made of a disc spring, and is disposed axially between the gear member 37 and the output member 39. The biasing member 61 biases the gear member 37 axially inward (toward the differential gear 11), and biases the output member 39 axially outward (toward the differential limiting unit 5). By disposing the biasing member 61 between the gear member 37 and the output member 39, a preload is applied to the differential limiting unit 5, and the on-off characteristics of the differential limiting unit 5 can be stabilized.

[0031] In such a differential device 1, the pair of output gears 13, 15 are composed of two members, a gear member 37 and an output member 39. A gap is formed between the gear member 37 and the output member 39. For example, a sealing member 63 that separates the inside and outside of the differential case 7 is disposed on one axial end side (axial inner side) of the gear member 37. In this case, the gap between the gear member 37 and the output member 39 communicates with the output parts 47, 49, and the lubricating oil that has flowed inside the differential case 7 flows out to the output parts 47, 49 and leaks outside the differential case 7.

[0032] Therefore, a sealing member 63 that divides the inside and outside of the differential case 7 is disposed on the sealing support portion 43 at one axial end side (axial inner side) of the output member 39. The sealing member 63 is formed, for example, in a cap shape that can close the opening of the sealing support portion 43. The sealing member 63 is assembled to the sealing support portion 43 so that the outer surface is in close contact with the inner surface of the sealing support portion 43. By disposing the sealing member 63 on the one axial end side of the output member 39, the gap between the gear member 37 and the output member 39 and the output portions 47, 49 (output shaft) are not communicated with each other. For this reason, the lubricating oil that has flowed inside the differential case 7 does not flow out between the output portions 47, 49 and the output shaft (not shown) and does not leak to the outside of the differential case 7.

[0033] Such a differential device 1 includes a rotatably arranged differential case 7 and a differential gear 11 that is rotatably supported by the differential case 7 and revolves with the rotation of the differential case 7. The differential device 1 also includes a pair of output gears 13, 15 that mesh with the differential gear 11 and are relatively rotatable. The output gears 13, 15 further include a gear member 37 that meshes with the differential gear 11, and an output member 39 that is arranged on the inner diameter side of the gear member 37 via an engagement portion 57 and is rotatable together with the gear member 37. A sealing member 63 that separates the inside and outside of the differential case 7 is arranged at an end of the output member 39.

[0034] By disposing the sealing member 63 at the end of the output member 39, the gap between the gear member 37 and the output member 39 does not communicate with the outside of the differential case 7. Therefore, the lubricating oil that has circulated inside the differential case 7 does not flow out to the output shaft side from the gap between the gear member 37 and the output member 39, and does not leak to the outside of the differential case 7.

[0035] Therefore, in such a differential device 1, in the output gears 13, 15 having the gear member 37 and the output member 39, the sealing member 63 can separate the inside and the outside of the differential case 7.

[0036] Further, one axial end of the output member 39 has a cylindrical gear support portion 41 that radially supports the gear member 37, and a cylindrical seal support portion 43 in which a seal member 63 is disposed.

[0037] Therefore, the gear member 37 can be stably supported by the gear support portion 41 of the output member 39, while the sealing member 63 can be disposed on the sealing support portion 43 of the output member 39 to separate the inside and outside of the differential case 7.

[0038] Moreover, the seal support portion 43 is located on the inner diameter side of the gear support portion 41 .

[0039] Therefore, the gear support portion 41 and the seal support portion 43 are arranged to overlap each other in the radial direction, which makes it possible to prevent the output member 39 from becoming large in the axial direction.

[0040] Further, the axial length of the gear support portion 41 is set to be longer than the axial length of the seal support portion 43 .

[0041] Therefore, the gear member 37 can be supported in the radial direction by the gear support portion 41 over a wide range in the axial direction, and the radial support of the gear member 37 by the gear support portion 41 can be stabilized.

[0042] Further, the seal support portion 43 is disposed on the inner diameter side of the gear member 37 with its radial thickness set to be thinner than that of the engagement portion 57 .

[0043] Therefore, by arranging the seal support portion 43 on the inner diameter side of the gear member 37 relative to the engaging portion 57, even if the thickness of the seal support portion 43 is made thinner, it does not affect the engagement of the engaging portion 57. In addition, by setting the thickness of the seal support portion 43 thinner than the engaging portion 57, it is possible to ensure the arrangement space for the sealing member 63 without increasing the size.

[0044] Further, a fixing portion 51 for fixing the output shaft is provided on the output member 39. The engagement portion 57 and the fixing portion 51 are disposed so that at least a portion of the axial direction overlaps with each other in the radial direction.

[0045] Therefore, by arranging the engaging portion 57 and the fixing portion 51 so as to overlap each other in the radial direction, it is possible to ensure high rigidity while saving space, and it is possible to stabilize the transmission of the driving force.

[0046] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

[0047] For example, in the differential gear according to the present embodiment, the differential limiting portion has a tapered ring arranged so as to be able to rotate integrally with the differential case, but this is not limiting, and the output member may slide on the inner wall surface of the differential case without using a tapered ring. Alternatively, the differential limiting portion may use a single flat disk-shaped plate or multiple plates arranged alternately.

[0048] In addition, the meshing combination between the differential gear and the pair of output gears is not limited to a bevel gear set, and various combinations can be used, such as a face gear set, a parallel shaft set with parallel shafts, etc. In any case, at least the output gear includes a gear member and an output member. [Explanation of symbols]

[0049] 1 Differential device 7 Differential Case 11 Differential gear 13,15 Output gear 37 Gear Materials 39 Output member 41 Gear support 43 Sealing support part 51 Fixed part 57 Engagement part 63 Sealing member

Claims

1. A rotatably disposed differential case; A differential gear that is rotatably supported by the differential case and revolves with the rotation of the differential case; a pair of output gears meshing with the differential gear and relatively rotatable; Equipped with the output gear includes a gear member that meshes with the differential gear, and an output member that is disposed on an inner diameter side of the gear member via an engagement portion so as to be integrally rotatable with the gear member, A differential device in which a sealing member that separates the inside and outside of the differential case is disposed at an end of the output member.

2. 2. The differential device according to claim 1, further comprising a cylindrical gear support portion, which supports the gear member in a radial direction, and a cylindrical seal support portion, in which the seal member is disposed, at one axial end side of the output member.

3. 3. The differential device according to claim 2, wherein the sealing support portion is located on an inner diameter side of the gear support portion.

4. 4. The differential device according to claim 2, wherein an axial length of the gear support portion is set to be longer than an axial length of the seal support portion.

5. 4. The differential device according to claim 2, wherein the seal support portion is disposed on an inner diameter side of the gear member and has a radial thickness smaller than that of the engagement portion.

6. The output member is provided with a fixing portion for fixing an output shaft, 4. The differential device according to claim 1, wherein the engaging portion and the fixing portion are disposed so as to overlap each other in at least a portion of the axial direction radially.

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