Differential device

Abstract

The present invention provides a differential that simplifies the configuration for adjusting the initial torque of the clutch, allowing for easy adjustment of the initial torque. [Solution] The differential gear includes a clutch, a pressing member, and an elastic member housed in a case, an adjustment member screwed to the case, and a fixing member for fixing the adjustment member so that it cannot rotate relative to the non-rotating member, or for releasing the fixing. The elastic member is a member that applies preload to generate initial torque in the clutch. The adjustment member is a member that presses the elastic member and can change the preload by tightening a screw. As a result, with the adjustment member fixed by the fixing member, the case rotates integrally with the output rotating members as a pair of output rotating members rotate in the same direction at the same rotational speed. When the case rotates, the screw of the adjustment member is tightened or loosened relative to the case, thereby adjusting the initial torque of the clutch.

Description

Technical Field

[0001] The present invention relates to a differential device provided with a mechanical differential limiting mechanism.

Background Art

[0002] A differential device including an input rotating member to which power is input and a pair of output rotating members to which the power input to the input rotating member is distributed, allowing differential in the pair of output rotating members, and causing the input rotating member and the pair of output rotating members to rotate integrally in a non-differential state where the pair of output rotating members have the same rotational speed is well known. For example, a differential device provided with a clutch as a mechanical differential limiting mechanism described in Patent Document 1 is such a device. Patent Document 1 discloses an initial torque adjustment mechanism capable of adjusting the initial torque (initial torque) of the clutch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the initial torque adjustment mechanism described in Patent Document 1 has a complicated structure and operation method. For example, the initial torque adjustment mechanism mechanism includes includes a flange disposed on a drive shaft protruding outside a differential case, a nut screwed to an end portion of the drive shaft and housed inside the flange, a disc spring disposed between the nut and the flange, and the like. Also, when operating the nut inside the flange to adjust the initial torque, a joint to which an axle on the tire side is connected and attached to an opening of the flange may interfere, or separation between the flange and the joint may be required.

[0005] The present invention was made against the above circumstances, and its objective is to provide a differential that simplifies the configuration for adjusting the initial torque of the clutch and allows for easy adjustment of the initial torque. [Means for solving the problem]

[0006] The gist of the first invention is a differential device comprising (a) an input rotating member to which power is input, and a pair of output rotating members to which the power input to the input rotating member is distributed, wherein differential is permitted in the pair of output rotating members, and in a non-differential state where the pair of output rotating members are rotated at the same rotational speed, the input rotating member and the pair of output rotating members are rotated integrally, and (b) a clutch as a mechanical differential limiting mechanism housed in the case of the input rotating member, which limits the differential by connecting the case and the output rotating members, ( c) a pressing member housed in the case that presses the clutch to generate a torque that limits the differential; (d) an elastic member housed in the case that applies a preload to the clutch to generate an initial torque; (e) an adjustment member screwed to the case that presses the elastic member to apply the preload and can change the preload by the amount of tightening of the screw; and (f) a fixing member that fixes the adjustment member so that it cannot rotate relative to the non-rotating member, or releases the fixing to the non-rotating member. [Effects of the Invention]

[0007] According to the first invention described above, the differential gear includes a clutch, a pressing member, and an elastic member housed in a case, an adjustment member screwed to the case, and a fixing member for fixing the adjustment member so that it cannot rotate relative to the non-rotating member, or for releasing the fixing. The clutch is a mechanical differential limiting mechanism. The pressing member is a member that presses the clutch so that it generates a torque that limits the differential. The elastic member is a member that applies preload to the clutch so that it generates an initial torque. The adjustment member is a member that presses the elastic member and can change the preload by tightening a screw. As a result, with the adjustment member fixed so that it cannot rotate relative to the non-rotating member by the fixing member, for example, when a pair of output rotating members rotate in the same direction at the same rotational speed, the case rotates integrally with the output rotating members. When the case rotates, the screw of the adjustment member, which is in a non-rotating state, is tightened or loosened relative to the case, so that the preload applied to the clutch by the elastic member is changed, and the initial torque of the clutch is adjusted. The initial torque adjustment amount can be controlled by the amount of rotation of the output rotating member. When the initial torque of the clutch is not adjusted, the fixing of the adjustment member by the fixing member is released. Therefore, the configuration for adjusting the initial torque of the clutch in the differential gear is simplified, and the initial torque can be easily adjusted. [Brief explanation of the drawing]

[0008] [Figure 1] This figure illustrates the schematic configuration of a vehicle equipped with a differential device to which the present invention is applied. [Figure 2] This is a cross-sectional view illustrating an example of the configuration of the differential device in this embodiment. (a) shows an overall view of the differential device. (b) shows a partial cross-sectional view illustrating an example of a configuration for applying preload to the clutch. [Figure 3] This figure illustrates an example of the initial adjustment mechanism in this embodiment. (a) shows the relative positional relationship between the differential case and the initial adjustment mechanism. (b) shows a perspective view of the initial adjustment mechanism. [Figure 4]This figure illustrates an example of the procedure for adjusting the initial torque in the differential device of this embodiment. (a) shows the state of the initial adjustment mechanism when adjusting the initial torque. (b) shows the state of the initial adjustment mechanism during driving. [Figure 5] This figure illustrates an example of adjusting the initial torque in the differential device of this embodiment. [Figure 6] This figure illustrates an example of adjusting the initial torque in a comparative differential device. (a) is a diagram illustrating the schematic configuration of a comparative differential device equipped with an initial torque adjustment mechanism. (b) is a diagram illustrating the schematic configuration of the initial torque adjustment mechanism of the comparative device. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0010] Figure 1 is a diagram illustrating the schematic configuration of a vehicle 10 equipped with a differential device 26 to which the present invention is applied. In Figure 1, the vehicle 10 comprises a power source 12, left and right drive wheels 14, and a power transmission device 16 provided in the power transmission path between the power source 12 and the drive wheels 14. The power source 12 is, for example, an engine as a known internal combustion engine. The power source 12 may also be, for example, an electric motor as a known rotating electric machine in addition to or instead of an engine. The drive wheels 14 include a left drive wheel 14L and a right drive wheel 14R. Note that "left and right" above refers to left and right with respect to the forward direction of the vehicle 10.

[0011] The power transmission device 16 includes a counter gear mechanism 20, a counter shaft 22, a final gear 24, a differential device 26, etc., within a housing 18. The housing 18 is a non-rotatable member attached to the vehicle body and is a non-rotating member of the present invention. The power transmission device 16 also includes left and right drive shafts 28 connected to the differential device 26. The counter gear mechanism 20 is a gear pair having a drive gear 20a and a driven gear 20b that meshes with the drive gear 20a. The drive gear 20a is connected to the power source 12, for example, directly or via a transmission (not shown). The driven gear 20b is connected to the final gear 24 via the counter shaft 22. The final gear 24 meshes with the differential ring gear 30 of the differential device 26. The drive shafts 28 include a left drive shaft 28L and a right drive shaft 28R. The drive shaft 28 connects the differential device 26 to the drive wheels 14. The power transmission device 16 transmits power from the power source 12 to the drive wheels 14.

[0012] The differential device 26 comprises a differential ring gear 30, a differential case 32, left and right differential side gears 34, a differential pinion 36, and a pinion shaft 38. The differential ring gear 30 is integrally connected to the outside of the differential case 32. The differential ring gear 30 and the differential case 32 are input rotating members of the present invention to which power from the power source 12 is input. The differential case 32 is supported by the housing 18 so as to be rotatable relative to it via bearings (not shown). The differential case 32 is the case of the present invention that houses the differential side gears 34, the differential pinion 36, and the pinion shaft 38, etc.

[0013] The differential side gear 34 includes a left side gear 34L and a right side gear 34R. The differential side gear 34 has spline teeth 34s (see Figure 2(a) described later) formed on the inner circumferential surface of a through hole into which the drive shaft 28 is fitted so as not to rotate relative to it. The differential pinion 36 meshes with the differential side gear 34. The differential pinion 36 is supported so as to be rotatable relative to the pinion shaft 38. The differential side gear 34 is a pair of output rotating members of the present invention to which the power input to the differential case 32 is distributed. The differential device 26 is a device that allows differential between the left and right differential side gears 34, and in a non-differential state where the left and right differential side gears 34 are rotated at the same rotational speed, the differential case 32 and the left and right differential side gears 34 are rotated integrally. The differential device 26 is a differential device of the present invention and functions, for example, as a differential device for a vehicle.

[0014] Figure 2 is a cross-sectional view illustrating an example of the configuration of the differential device 26 in this embodiment. Figure 2 shows the differential device 26 and the drive shaft 28 before assembly. Figure 2(a) shows an overall view of the differential device 26. Figure 2(b) shows a partial cross-sectional view illustrating an example of a configuration in which preload is applied to the clutch as a differential limiting mechanism.

[0015] In Figure 2, the differential device 26 further comprises left and right clutches 40 and left and right pressure rings 50 housed in the differential case 32. The clutches 40 include a left clutch 40L and a right clutch 40R. The pressure rings 50 include a left pressure ring 50L and a right pressure ring 50R.

[0016] The clutch 40 is inserted between the differential case 32 and the differential side gear 34. The clutch 40 includes a plurality of outer plates 42 and inner plates 44 that are alternately arranged. The outer peripheral portion of the outer plate 42 is spline-fitted to the inner peripheral surface of the differential case 32. The inner peripheral portion of the inner plate 44 is spline-fitted to the outer peripheral surface of the end portion of the differential side gear 34 on the side opposite to the pinion shaft 38. The clutch 40 is a friction clutch that generates frictional force when the outer plate 42 and the inner plate 44 are pressed against each other. The clutch 40 is a mechanical differential limiting mechanism of the present invention that limits differential in the differential device 26 by connecting the differential case 32 and the differential side gear 34.

[0017] The pressure ring 50 has an outer peripheral surface that is spline-fitted to the inner peripheral surface of the differential case 32, and a cam 50c formed at the end portion on the pinion shaft 38 side is engaged with the pinion shaft 38. The pressure ring 50 has an end portion on the side opposite to the pinion shaft 38 abutted against the clutch 40, and sandwiches the clutch 40 between itself and the differential case 32. The pressure ring 50 is a pressing member of the present invention that presses the clutch 40 so as to generate torque for limiting differential in the clutch 40.

[0018] In the differential device 26, when a rotational difference (rotational speed difference or torque difference) of a predetermined rotational difference or more occurs between the left and right differential side gears 34, the pressure ring 50 is slid to the side opposite to the pinion shaft 38. As a result, the clutch 40 is slip-engaged, and the differential in the differential device 26 is restricted. The differential device 26 is a limited slip differential (LSD) including the clutch 40 as a mechanical differential limiting mechanism. The rotational difference between the left and right differential side gears 34 is synonymous with the rotational difference between the left and right drive shafts 28 or the rotational difference between the left and right drive wheels 14.

[0019] Regarding at what timing to activate the differential limit in the differential device 26, that is, regarding the predetermined rotational difference, for example, it depends on the preload for pre-pressing the clutch 40 in advance. For example, the greater the preload, the differential limit is performed from a region where the rotational difference between the left and right differential side gears 34 is smaller.

[0020] The differential device 26 further includes an initial adjustment mechanism 60. The initial adjustment mechanism 60 includes a disc spring 62, a piston 64, and an adjustment dial 66.

[0021] The disc spring 62 is housed in the differential case 32. The disc spring 62 is an elastic member of the present invention that applies a preload to generate an initial torque (initial torque) on the clutch 40 by sandwiching the clutch 40 (left clutch 40L in this embodiment) between the pressure ring 50 (left pressure ring 50L in this embodiment).

[0022] The differential case 32 has a cylindrical protruding portion 32a that protrudes to the side opposite to the clutch 40, that is, the adjustment dial 66 side, and the adjustment dial 66 side is open. The piston 64 is housed inside the protruding portion 32a in the radial direction. The piston 64 is an intermediate member of the present invention that is disposed between the disc spring 62 and the adjustment dial 66 and is pushed by the adjustment dial 66 to press the disc spring 62. The adjustment dial 66 presses the disc spring 62 via the piston 64 so that the disc spring 62 applies a preload.

[0023] The protruding portion 32a has an internal thread 32as formed on its inner circumferential surface 32ai. The adjustment dial 66 has an external thread 66s formed on its outer circumferential surface 66o that engages with the internal thread 32as of the protruding portion 32a. The adjustment dial 66 is screwed into the differential case 32 (the protruding portion 32a in this embodiment). When the screw of the adjustment dial 66 is tightened, the disc spring 62 is pressed, generating a preload that the disc spring 62 provides. The more the screw of the adjustment dial 66 is tightened, the greater the preload provided by the disc spring 62. The more the screw of the adjustment dial 66 is loosened, the smaller the preload provided by the disc spring 62. The adjustment dial 66 is an adjustment member of the present invention that can change the preload provided by the disc spring 62 depending on the amount the screw is tightened. Changing the preload applied by the disc spring 62 is equivalent to changing the initial torque of the clutch 40, in other words, adjusting the initial torque of the clutch 40.

[0024] Thus, the differential device 26 has a structure that pushes a disc spring 62, which is located on one side of the clutch 40, from the outside of the differential case 32. The initial torque of the clutch 40 is adjusted by the degree to which the disc spring 62 is pushed in by the differential device 26. The differential device 26 is an LSD with adjustable initial torque of the clutch 40. The initial adjustment mechanism 60 is an initial torque adjustment mechanism that can adjust the initial torque of the clutch 40.

[0025] Figure 6 illustrates an example of initial torque adjustment in the comparative differential device 100. Figure 6(a) illustrates the schematic configuration of the comparative differential device 100 equipped with the comparative initial torque adjustment mechanism 110. Figure 6(b) illustrates the schematic configuration of the comparative initial torque adjustment mechanism 110. In Figure 6, the differential device 100 functions as a known differential. The differential device 100 also includes a clutch 120 that functions as a mechanical differential limiting mechanism. The initial torque adjustment mechanism 110 includes a piston 112, an adjustment dial 114, an adjustment screw 116, and a spring 118. In the initial torque adjustment mechanism 110, the adjustment dial 114 is rotated by turning the adjustment screw 116. This changes the force with which the piston 112 presses against the clutch 120 in the differential device 100, thereby adjusting the initial torque of the clutch 120. In the differential device 100, when the initial torque of the clutch 120 is adjusted, the adjustment dial 114 is turned by operating the adjustment screw 116 while the differential case 130 is fixed. In the differential device 100, since the initial torque is adjusted externally using the adjustment screw 116, both the adjustment dial 114 and the adjustment screw 116 require gears A and B for turning the adjustment dial 114. Furthermore, in the differential device 100, gears A and B must mesh when adjusting the initial torque, and not mesh when driving. For this reason, it is necessary to provide a spring 118 that can separate the adjustment screw 116 from the adjustment dial 114, or a sliding seal to prevent oil leakage at the part where the adjustment screw 116 slides against the differential case 130. This makes the structure for disengaging gears A and B when driving more complex. Furthermore, because the gear ratio in gears A and B is large, a large amount of adjustment, or rotational speed, is required for the adjustment screw 116. In addition, it is difficult to visually perceive the amount of initial torque adjustment. As a result, it is necessary to operate the adjustment screw 116 many times to adjust the initial torque.

[0026] Figure 3 illustrates an example of the initial adjustment mechanism 60 in this embodiment. Figure 3(a) shows the relative positional relationship between the differential case 32 and the initial adjustment mechanism 60 (excluding the disc spring 62). Figure 3(b) shows a perspective view of the initial adjustment mechanism 60 (excluding the disc spring 62).

[0027] In Figure 3, the initial adjustment mechanism 60 further includes a fixing bolt 68. The fixing bolt 68 is a component for fixing the adjustment dial 66 to the housing 18 when adjusting the initial torque of the clutch 40. In other words, the fixing bolt 68 is a fixing component of the present invention that fixes the adjustment dial 66 to the housing 18 so that it cannot rotate relative to the housing 18, or releases the fixing of the adjustment dial 66 to the housing 18. By being attached to the housing 18, the fixing bolt 68 fixes the adjustment dial 66 to the housing 18 so that it cannot rotate relative to the housing 18 (see Figure 4(a) described later). By removing the fixing bolt 68 from the housing 18, the fixing of the adjustment dial 66 to the housing 18 is released. The adjustment dial 66 has a claw portion 66n that engages with the fixing bolt 68. The claw portion 66n is formed on the outer circumferential surface 66o of the adjustment dial 66, protruding radially outward. Multiple claw portions 66n are formed, for example, at approximately equal intervals in the circumferential direction. The adjustment dial 66 has a male thread 66s formed on the clutch 40 side of its outer circumferential surface 66o, and a claw portion 66n formed on the side of its outer circumferential surface 66o opposite to the clutch 40. The adjustment dial 66 is fixed to the housing 18 by the fixing bolt 68, so that it cannot rotate relative to the housing 18, as the claw portion 66n engages with the fixing bolt 68.

[0028] Figure 4 illustrates an example of the initial torque adjustment procedure in the differential device 26 of this embodiment. Figure 4(a) shows the state of the initial adjustment mechanism 60 when adjusting the initial torque. Figure 4(b) shows the state of the initial adjustment mechanism 60 during driving. Figure 5 illustrates an example of initial torque adjustment in the differential device 26 of this embodiment.

[0029] In Figure 4(a), when adjusting the initial torque, the fixing bolt 68 is attached to the housing 18. This causes the claw portion 66n of the adjustment dial 66 to engage with the fixing bolt 68, fixing the adjustment dial 66 so that it cannot rotate relative to the housing 18. The housing 18 has a hole 18h into which the fixing bolt 68 is attached. The hole 18h has a female thread 18hs that is screwed into the fixing bolt 68. The differential device 26 may further include a housing 18 that houses the differential case 32 and the adjustment dial 66, etc., as non-rotating members. The fixing bolt 68 is the bolt of the present invention, having a length that allows the claw portion 66n to engage when attached to the hole 18h.

[0030] In Figure 5, with the fixing bolt 68 attached to the housing 18 and the adjustment dial 66 fixed to the housing 18 so as to be unable to rotate relative to it, the differential case 32 rotates integrally with the drive wheels 14 as the left and right drive wheels 14 rotate in the same direction at the same rotational speed. When the differential case 32 rotates, the male screw 66s of the adjustment dial 66, which is in a non-rotating state, is tightened or loosened relative to the differential case 32. This changes the pressure of the piston 64 on the disc spring 62, thereby changing the preload applied to the clutch 40 by the disc spring, and adjusting the initial torque of the clutch 40. The amount of adjustment of the initial torque can be controlled by the rotation angle of the drive wheels 14.

[0031] In the differential device 26, when the initial torque of the clutch 40 is adjusted, the differential case 32 is rotated while the adjustment dial 66 is fixed. The differential device 26 has a structure that allows a disc spring 62 located on one side of the clutch 40 to be pushed in from the outside. In the differential device 26, the initial torque can be adjusted by fixing the adjustment dial 66 from the outside and rotating the drive wheel 14 to change the amount of screwing the adjustment dial 66 into the differential case 32. The differential device 26 is an LSD in which the initial torque can be adjusted from outside the unit.

[0032] In Figure 4(b), the differential device 26 is further equipped with a release bolt 70 that does not engage with the claw portion 66n of the adjustment dial 66. During driving, the release bolt 70 is attached to the hole 18h of the housing 18. As a result, the adjustment dial 66 is made rotatable relative to the housing 18 and rotates integrally with the differential case 32, so the initial torque of the clutch 40 is not adjusted. The hole 18h is also the hole to which the release bolt 70 is attached. The release bolt 70 is a second bolt of the present invention that is attached to the hole 18h in place of the fixing bolt 68 and has a length shorter than the length to which the claw portion 66n engages when attached to the hole 18h.

[0033] When the initial torque of the clutch 40 is not being adjusted, the release bolt 70 is attached to the housing 18. When adjusting the initial torque, the release bolt 70 is replaced with a fixing bolt 68. This allows the initial torque to be adjusted. After the initial torque has been adjusted, the fixing bolt 68 is replaced with the release bolt 70. As a result, when the initial torque is not being adjusted, the fixing bolt 68 releases the adjustment dial 66 from the housing 18.

[0034] In the differential device 26 of this embodiment, gears A and B (see Figure 6), which were required in the comparative differential device 100, are not needed for adjusting the initial torque, thus simplifying the configuration. Furthermore, in the differential device 26 of this embodiment, mass-produced bolts can be used as fixing bolts 68 and release bolts 70. In addition, in the differential device 26 of this embodiment, the initial torque of the clutch 40 can be adjusted by rotating the drive wheel 14, making it easy to change the initial torque.

[0035] As described above, according to this embodiment, the differential device 26 includes a clutch 40, a pressure ring 50, a disc spring 62, an adjustment dial 66, and a fixing bolt 68. The clutch 40 is a mechanical differential limiting mechanism. The pressure ring 50 is a member that presses the clutch 40 to generate a torque that limits the differential. The disc spring 62 is a member that applies preload to the clutch 40 to generate an initial torque. The adjustment dial 66 is screwed into the differential case 32 and is a member that presses the disc spring 62 and changes the preload by tightening the screw. The fixing bolt 68 is a member that fixes the adjustment dial 66 to the housing 18 so that it cannot rotate relative to it, or releases that fixation. As a result, when the adjustment dial 66 is fixed to the housing 18 so that it cannot rotate relative to it by the fixing bolt 68, for example, when a pair of differential side gears 34 are rotated in the same direction at the same rotational speed, the differential case 32 is rotated integrally with the differential side gears 34. When the differential case 32 is rotated, the male screw 66s of the adjustment dial 66, which is in a non-rotating state, is tightened or loosened relative to the differential case 32, thereby changing the preload applied to the clutch 40 by the disc spring 62, and adjusting the initial torque. The amount of adjustment of the initial torque can be controlled by the amount of rotation of the differential side gear 34, that is, the rotation angle of the drive wheel 14. When the initial torque is not adjusted, the fixing bolt 68 releases the adjustment dial 66. Thus, the configuration for adjusting the initial torque of the clutch 40 in the differential device 26 is simplified, and the initial torque can be easily adjusted.

[0036] Furthermore, according to this embodiment, the differential case 32 has a projection 32a that protrudes toward the adjustment dial 66 side and is open toward the adjustment dial 66 side. The projection 32a has an internal thread 32as formed on its inner circumferential surface 32ai. The adjustment dial 66 has an external thread 66s formed on its outer circumferential surface 66o that engages with the internal thread 32as of the projection 32a. The differential device 26 further includes a piston 64 housed radially inward of the projection 32a, which is pressed by the adjustment dial 66 to press the disc spring 62. This allows the amount of initial torque adjustment to be appropriately controlled by the rotation angle of the drive wheel 14.

[0037] Furthermore, according to this embodiment, the adjustment dial 66 has a claw portion 66n that protrudes radially outward from its outer circumferential surface 66o and engages with the fixing bolt 68. As a result, the adjustment dial 66 is fixed to the housing 18 by the fixing bolt 68 so that it cannot rotate relative to the housing 18, because the claw portion 66n engages with the fixing bolt 68.

[0038] Furthermore, according to this embodiment, the differential device 26 further includes a housing 18 as a non-rotating member, which houses the differential case 32 and the adjustment dial 66, and has a hole 18h with an internal thread 18hs into which a fixing bolt 68 is attached. The fixing bolt 68 is a bolt that has a length such that the claw portion 66n engages when it is attached to the hole 18h. As a result, when adjusting the initial torque of the clutch 40, the fixing bolt 68 is attached to the housing 18, and the adjustment dial 66 is fixed to the housing 18 so that it cannot rotate relative to the housing 18.

[0039] Furthermore, according to this embodiment, the differential device 26 also includes a release bolt 70 that is attached to the hole 18h in place of the fixing bolt 68 and has a length shorter than the length over which the claw portion 66n engages when attached to the hole 18h. As a result, when the initial torque of the clutch 40 is not being adjusted, the release bolt 70 is attached to the housing 18 in place of the fixing bolt 68, and the fixing of the adjustment dial 66 to the housing 18 by the fixing bolt 68 is released.

[0040] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0041] For example, in the embodiment described above, when adjusting the initial torque of the clutch 40, the differential case 32 was rotated integrally with the drive wheels 14 by rotating the left and right drive wheels 14 in the same direction at the same rotational speed, but the embodiment is not limited to this. It is sufficient for the differential case 32 to be rotated while the adjustment dial 66 is fixed to the housing 18 so as not to rotate relative to it. For example, the differential case 32 may be rotated by rotating the other drive wheel while one of the left and right drive wheels 14 is stopped from rotating.

[0042] Furthermore, in the above-described embodiment, the fixing member that secures the adjustment dial 66 to the housing 18 so that it cannot rotate relative to it, or releases the fixing of the adjustment dial 66 to the housing 18, was a fixing bolt 68 that was screwed into the hole 18h, but the embodiment is not limited to this. For example, the fixing member may be a simple rod without threads.

[0043] Furthermore, in the above-described embodiment, when the initial torque of the clutch 40 is not adjusted, a release bolt 70 is attached to the housing 18 in place of the fixing bolt 68, but the embodiment is not limited to this. For example, when the initial torque of the clutch 40 is not adjusted, a cover or the like that closes the hole 18h may be attached to the hole 18h in place of the fixing member.

[0044] Furthermore, in the above-described embodiment, a differential device 26 that distributes input power to the left and right drive wheels 14 was exemplified as the differential device to which the present invention is applied, but the invention is not limited to this embodiment. The differential device to which the present invention is applied may be, for example, a center differential device that absorbs the rotational difference between the front and rear wheels in a front and rear wheel drive vehicle.

[0045] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0046] 18: Housing (non-rotating member) 18h: Hole 18hs: Female thread 26: Differential device (differential gear) 30: Differential ring gear (input rotating member) 32: Differential case (input rotating member, case) 32a: Protrusion 32ai: Inner surface 32as: Female thread 34 (34L, 34R): Differential side gear (output rotating member) 40 (40L, 40R): Clutch (differential limiting mechanism) 50 (50L, 50R): Pressure ring (pressing member) 62: Disc spring (elastic member) 64: Piston (intermediate member) 66: Adjustment dial (adjustment member) 66n: Claw part 66o: Outer surface 66s: Male thread 68: Fixing bolt (fixing member, bolt) 70: Release bolt (second bolt)

Claims

1. A differential device comprising an input rotating member to which power is input, and a pair of output rotating members to which the power input to the input rotating member is distributed, wherein differential operation is permitted in the pair of output rotating members, and in a non-differential state where the pair of output rotating members rotate at the same rotational speed, the input rotating member and the pair of output rotating members rotate as a single unit, A clutch, which is a mechanical differential limiting mechanism housed in the case serving as the input rotating member, connects the case and the output rotating member to limit the differential, A pressing member housed in the case presses the clutch to generate a torque that limits the differential, An elastic member housed in the case applies preload to the clutch to generate initial torque, An adjustment member, which is screwed into the case, presses the elastic member to apply the preload and changes the preload by the amount the screw is tightened, A fixing member for fixing the adjustment member so that it cannot rotate relative to the non-rotating member, or for releasing the fixing from the non-rotating member, A differential device characterized by including

2. The case has a protruding portion that extends toward the adjustment member and has an opening toward the adjustment member, The aforementioned protrusion has an internal thread formed on its inner circumferential surface. The adjustment member has a male thread formed on its outer circumferential surface that engages with the female thread of the protrusion. The differential device according to claim 1, further comprising an intermediate member housed radially inward of the protrusion, which is pressed by the adjusting member to press against the elastic member.

3. The differential device according to claim 1 or 2, characterized in that the adjusting member has a claw portion formed on its outer circumferential surface that protrudes radially outward and engages with the fixing member.

4. The non-rotating member further includes a housing that accommodates the case and the adjustment member, and has a hole with an internal thread for attaching the fixing member. The differential device according to claim 3, characterized in that the fixing member is a bolt having a length such that the claw portion engages when it is attached to the hole.

5. The differential device according to claim 4, further comprising a second bolt which is attached to the hole in place of the bolt and has a length shorter than the length to which the claw portion engages when attached to the hole.

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