JPH0581554U - Differential device - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a differential device in which shock, vibration, noise of a differential gear and abnormal wear such as springs are reduced to improve durability. A differential device 7 of the present invention comprises a differential case 21 that is rotationally driven by a driving force of an engine,
A pinion gear 33 rotatably supported by a pinion shaft 31 supported by the differential case 21, a pair of side gears 35 and 37 that mesh with the pinion gear 33 and are connected to an axle, a cylindrical surface on the inner circumference of the differential case 21, and a pinion gear. Spherical washer 3 disposed between
9 and a leaf spring 41 arranged so as to press the pinion gear 33 against the side gears 35, 37 between the differential case 21 and the spherical washer 39.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a differential device used in a vehicle.

[0002]

[Prior Art]

 Japanese Unexamined Patent Publication (Kokai) No. 58-149440 discloses a differential device as shown in FIG. This applies an initial torque to the differential limiting multi-plate clutches 203 and 203 of the differential mechanism 201 with a disc spring 205. In addition, as shown in FIG. 7, in the differential device in which a multi-plate clutch is arranged between the differential case 207 and the side gear as in the device of FIG. 6, the disc spring 211 is arranged between the differential case 207 and the pinion gear 209. Then, the pinion gear 209 is pressed against the side gear, and an initial torque is applied to the multi-plate clutch by the generated cam thrust force.

Further, in the differential device as shown in FIG. 8, a differential mechanism 303 and a coupling device 305 for limiting the differential by viscous fluid are arranged in the differential case 301. The pinion gear 307 meshes with one side gear 309 and the other side gear 311 formed on the side wall of the coupling device 305, and a spherical washer 313 is arranged between the differential case and the pinion gear.

[0004]

[Problems to be solved by the device]

 However, in the device shown in FIG. 6, the disc spring 205 is disposed between the differential case 213 and the side gears 215, 215 that rotate relative to each other, and since the disc spring 205 has an extreme contact with the edge, friction between the disc spring 205 and the side gears 215, 215 occurs. Is likely to occur.

In the device shown in FIG. 7, the disc-shaped disc spring 211 has a limited diameter d in order to avoid interference with other members. Therefore, the spring is shortened accordingly, the spring constant is increased, and the effective deflection amount is increased. Get smaller. If the amount of flexure is insufficient, the flexure is absorbed by the backlash between the pinion gear and the side gear, and the spring force does not reach the multiple disc clutch. In this state, the differential limiting force due to the initial torque cannot be obtained, and when one wheel spins on a bad road or the like, the driving force of the other wheel is also lost and the running performance of the vehicle is significantly reduced.

Each time the pinion gear moves beyond the limit where the flexure of the disc spring becomes zero, a change occurs such that the backlash and the pressing force of the multi-plate clutch disappear or occur, and this is because the spring constant is large. To be remarkable. Therefore, impact, vibration, noise, etc. occur at the meshing portion of each gear and the multi-plate clutch, and durability deteriorates. Also, in the device shown in FIG. 7, the disc spring 211 is likely to be abnormally worn by the rotation of the pinion gear 209.

Further, when a load is applied to the differential device, when the pinion gear moves due to the meshing reaction force with the side gear, the shock is absorbed by the friction of the meshing part and the friction with the pinion shaft. The impact absorption effect is also small because the amount of movement of the pinion gear cannot be set to a large amount due to the insufficient amount of flexure of the. Furthermore, since the spring constant of the disc spring 211 is large and the reaction force during movement of the pinion gear is large, the impact of the meshing portion is also increased, and the durability is reduced.

Further, in the device of FIG. 8, rattling noise is generated due to the meshing of the pinion gear and the pair of side gears during the differential rotation of the differential mechanism. This is due to the backlash of these meshing teeth. To prevent rattling noise, the precision of each gear was improved, and the washer 315, 317 plate thickness was changed to reduce backlash. There are limits. Further, the gear backlash of the meshing teeth may increase due to the wear of the gears over time, and a loud rattling noise may be generated.

Therefore, an object of the present invention is to provide a differential device in which shock, vibration, noise of a differential gear and abnormal wear such as springs are reduced to improve durability.

[0010]

[Means for Solving the Problems]

 The differential device of this invention includes a differential case that is rotationally driven by the driving force of an engine, a pinion gear that is rotatably supported by a pinion shaft supported by the differential case, and a pair of gears that are engaged with the pinion gear and are connected to an axle. Side gears, a spherical washer arranged between the cylindrical surface on the inner circumference of the differential case and the pinion gear, and a leaf spring arranged between the differential case and the spherical washer to press the pinion gear against the side gear. It is characterized by

[0011]

[Action]

 Unlike leaf springs, leaf springs are not limited in outer shape.Therefore, it is possible to use rectangular leaf springs with a width in the axial direction that does not interfere with other members, while giving a sufficient length in the circumferential direction of the differential case. Therefore, the spring constant can be appropriately reduced, and a sufficient amount of bending can be obtained in the moving direction of the pinion gear.

Therefore, the leaf spring can always press the pinion gear against the side gear with zero backlash. Therefore, the impact, vibration, noise, etc. in the differential gear are reduced, and the durability is improved. Since the amount of flexure of the leaf spring is large enough, it is possible to set a large amount of movement of the pinion gear, and when the differential device is loaded, the friction of the meshing part with the side gear and the friction with the pinion shaft are absorbed. The effect is large and the spring constant is small, so the reaction force to the meshing part is small and the impact is small.

Further, since the leaf spring is arranged between the differential case and the spherical washer, abnormal wear due to rotation of the pinion gear does not occur.

[0014]

【Example】

 One embodiment will be described with reference to FIGS. FIG. 1 shows a differential device of this embodiment, and FIG. 5 shows a power system of a vehicle using this differential device. Hereinafter, the left and right directions are the left and right directions in this vehicle and FIG.

As shown in FIG. 5, the power system includes an engine 1, a transmission 3, a propeller shaft 5, a rear differential 7 (a differential device of FIG. 1 arranged on the rear wheel side), rear axles 9, 11 and left and right rear axles. It is composed of wheels 13, 15 and left and right front wheels 17, 19. The driving force of the engine 1 is transmitted to the rear differential gear 7 via the transmission 3 and the propeller shaft 5, and is distributed to the left and right rear wheels 13, 15 via the rear differential gear 7, as will be described later.

The differential case 21 of the rear differential 7 is rotatably arranged in the differential carrier 23. A ring gear 25 is fixed to the differential case 21, and the ring gear 25 meshes with a drive pinion gear 27. The drive pinion gear 27 is formed integrally with a drive pinion shaft 29 connected to the propeller shaft 5 side. In this way, the differential case 21 is rotationally driven by the driving force of the engine 1.

As shown in FIG. 1, a pinion shaft 31 is supported by the differential case 21, and pinion gears 33, 33 are rotatably supported by the pinion shaft 31. Left and right side gears 35 and 37 are meshed with these pinion gears 33 and 33. The left side gear 35 is splined to the left rear axle 9, and the right side gear 37 is splined to the right rear axle 11. ing.

The driving force of the engine 1 that rotates the differential case 21 is transmitted from the pinion shaft 31 to the side gears 35 and 37 via the pinion gears 33 and 33, and is distributed to the left and right rear wheels 13 and 15, respectively. Further, when a driving resistance difference occurs between the rear wheels, the driving force of the engine 1 is differentially distributed to the left and right sides due to the rotation and revolution of the pinion gear 33.

A spherical washer 39 is arranged on the differential case 21 side of each pinion gear 33, and a rectangular leaf spring 41 is arranged between the cylindrical surface of the differential case 21 and the spherical washer 39. When viewed from the side, the leaf spring 41 has a shape as shown by the broken line in FIG. 2 when viewed from the side, and when the rear differential 7 is assembled, it receives the pressing force of the pinion gear 33 that moves when the side gears 35 and 37 mesh with each other. As a result, as shown in FIG. 3, the differential case 21 is deformed and bent along the cylindrical surface.

Multiple disc clutches 43 and 45 are arranged between the differential case 21 and the side gears 35 and 37, respectively. The leaf spring 41 presses the pinion gear 33 against the side gears 35 and 37 via the spherical washer 39 as shown by an arrow 47 in FIG. 1, and the cam thrust force 49 generated in the meshing portion causes the multiple disc clutch via the side gears 35 and 37. 43 and 45 are pressed to apply initial torque. Further, the multi-plate clutches 43, 45 during driving of the rear wheels 13, 15 are fastened by receiving a meshing reaction force generated in the side gears 35, 37 meshing with the pinion gear 33. Differential limitation is performed by the multi-plate clutches 43 and 45 thus fastened.

Graphs 51 and 53 in FIG. 4 show torque distribution characteristics of the rear differential due to such a differential limiting force. Graph 51 shows the axial torque transmitted to the left rear wheel 13 when the right rear wheel 15 idles. The graph 53 shows the shaft torque transmitted to the right rear shaft 15 when the left rear wheel 13 idles. Graph 55 shows the torque distribution characteristics of the differential device having no differential limiting function shown for comparison with these, and shows that when one wheel spins, the other wheel also loses driving force. .. The line segments 57 and 59 of the graphs 51 and 53 are based on the initial torque, and the line segments 61 and 63 are based on the meshing reaction force. Since the meshing reaction force increases as the transmission torque increases, the gradient of each of the line segments 61 and 63 is greatly inclined in the direction in which the distributed torque increases.

As shown in FIG. 1, the leaf spring 41 has a circumferential length l (FIG. 2) on the inner peripheral surface of the cylinder of the differential case 21 while the width w is appropriately narrowed in order to avoid interference with the side gears 35 and 37. Can be long enough. Therefore, the amount of flexure is sufficiently large that a pressing force can be applied to the pinion gear 33 in the entire movement range of the pinion gear 33, and the backlash between the pinion gear 33 and the side gears 35 and 37 can be kept to zero, while the multi-plate clutch 43 is maintained. , 45 can be given a stable initial torque. Therefore, unlike the conventional example, when the pinion gear moves, the initial torque disappears, and the differential limiting force is not lost as shown in the graph 55 of FIG. 4 to prevent the vehicle from running on rough roads. Further, since the backlash is kept at zero, there is no collision between the side gears 35, 37 and the pinion gear 33, and shock, vibration, noise, etc. are prevented and durability is improved. Further, unlike the conventional example, the multi-plate clutches 43 and 45 are always engaged stably without the pressing force being cut off, so that shock, vibration, noise and abnormal wear of the friction plate are prevented, and durability is improved. improves.

Further, since the amount of bending of the leaf spring 41 is sufficiently large, the amount of movement of the pinion gear 33 along the pinion shaft 31 can be set to be large. Therefore, when a load is applied to the meshing portion with the side gears 35, 37, the meshing reaction force causes the pinion gear 33 to move largely, and the shock absorbing effect due to the friction of the meshing portion and the friction with the pinion shaft 31 is large. Further, by increasing the length l of the leaf spring 41, the spring constant becomes smaller, the force for pushing back the pinion gear 33 when the load is applied is moderately moderated, and the impact of the meshing portion is reduced accordingly. For these reasons, shock, vibration and noise are reduced and durability is further improved.

Further, the arrangement of the spherical washer 39 prevents abnormal wear due to relative rotation of the leaf spring 41 and the pinion gear 33.

The rear differential 7 is thus constructed.

As shown in graphs 51 and 53 of FIG. 4, when one of the rear wheels 13 and 15 idles, the rear differential 7 distributes a sufficient driving force to the other from the low torque region to the high torque region. The vehicle has excellent driving performance on rough roads, straight line stability, and turning performance.

[0027]

[Effect of the device]

 Since the differential device of the present invention uses a plate spring between the differential case and the spherical washer to obtain a sufficient amount of deflection and to appropriately reduce the spring constant, the shock, vibration, and noise generated in the differential gear are reduced. Reduced and improved durability. Also, abnormal wear due to relative rotation of the leaf spring and pinion gear was prevented by placing a spherical washer between them to improve durability.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a side view of a leaf spring.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a graph showing torque distribution characteristics of the embodiment of FIG.

5 is a skeleton mechanism diagram showing a power system of a vehicle using the embodiment of FIG. 1. FIG.

FIG. 6 is a sectional view of a conventional example.

FIG. 7 is a partial cross-sectional view of another conventional example.

FIG. 8 is a cross-sectional view of another conventional example.

[Explanation of symbols]

 7 Rear differential (differential device) 21 Differential case 31 Pinion shaft 33 Pinion gear 35, 37 Side gear 39 Spherical washer 41 Leaf spring 43, 45 Multi-disc clutch

Claims (1)

[Scope of utility model registration request] 1. A differential case which is rotationally driven by a driving force of an engine, a pinion gear which is rotatably supported by a pinion shaft supported by the differential case, and a pair of side gears each of which meshes with the pinion gear and is connected to an axle. A spherical spring washer arranged between the cylindrical surface of the inner periphery of the differential case and the pinion gear, and a leaf spring arranged to press the pinion gear against the side gear between the differential case and the spherical washer. Differential device.