JPH0829684B2 - Power distribution device for front and rear wheels - Google Patents

Description

The present invention relates to a power distribution device for front and rear wheels in a four-wheel drive vehicle.

(Prior Art) As one type of power distribution device for front and rear wheels, a differential case that rotates at the output of a transmission and a pinion gear shaft that is assembled to this case are rotatably assembled in the same case. A plurality of pinion gears housed therein, and a pair of side gears that are rotatably assembled in the case, mesh with the respective pinion gears, and are connected to the front wheel side and the rear wheel side so that torque can be transmitted respectively. There is one, and this is currently called the center differential.

By the way, it is preferable to control the distribution of power distribution to the front and rear wheels in a four-wheel drive vehicle to an appropriate value according to the running state of the vehicle and the friction coefficient of the road surface. However, at present, the center differential does not have a mechanism for varying the distribution of power distribution, and the power distribution is generally constant, and such a center differential has a mechanism for varying power distribution. However, it is only found in the power transmission device disclosed in Japanese Patent Laid-Open No. 62-12421.

Thus, in the center differential of such a power transmission device, the tooth portion that meshes with each pinion gear of each side gear is formed in an arcuate concave shape, and
The tooth portion of each pinion gear is formed in an arcuate convex shape corresponding to the tooth portion, and each pinion gear meshes with the side gear between both side gears and turns in an arc shape along the tooth portion of the side gear. It is assembled to move. As a result, each pinion gear is appropriately rotated by an external operation,
The distance from the shaft center of each side gear to the meshing portion of each pinion gear changes, and the power distribution to the front and rear wheels changes.

(Problems to be solved by the invention) By the way, in such a center differential, the shape of each pinion gear and each side gear is a peculiar shape greatly different from the conventional one, and the assembling structure of each pinion gear is also different from the conventional one. It has a different and unique structure.
Therefore, when adopting such a center differential, it is necessary to change all or many of the conventional center differential components, and also change the method of assembling each component.
It is extremely economically disadvantageous.

Therefore, an object of the present invention is to provide a variable function of power distribution by minimizing the change of the conventional constituent members in the center differential of the type described above.
It is to make it extremely economically advantageous.

(Means for Solving Problems) The present invention relates to a differential case that rotates at the output of a transmission,
A plurality of pinion gears rotatably mounted on the pinion gear shaft mounted in this case and housed in the same case, and a plurality of pinion gears rotatably mounted in the case and meshing with the respective pinion gears and front wheel side And a power distribution device for front and rear wheels including a pair of side gears that are respectively coupled to the rear wheel side so as to be able to transmit torque, wherein the power distribution device is such that the pinion gear shaft is operated by an external operation with respect to the case. The pinion gear is mounted so as to be movable by a predetermined amount in the axial direction, and the pinion gear is rotatably mounted on the pinion gear shaft via an eccentric ring.

(Operation and Effect of the Invention) In the power distribution device having such a configuration, the differential case,
By the operation of each pinion gear, pinion gear shaft, and each side gear, the power from the transmission is distributed to the front wheel side and the rear wheel side via each side gear shaft. When the pinion gear shaft is moved in the axial direction of the side gear by an external operation, the differential case, the pinion gear shaft and the eccentric ring, and the pinion gear and the side gear relatively rotate about the axis of the side gear. As a result, the pinion gear shaft also moves in the axial direction of the side gear, and the distance between the axis of the pinion gear shaft and each of the pinion gear and the meshing portion of each side gear changes, and accordingly the front and rear wheels are moved. The power distribution of will also change.

By the way, in the power distribution device, in order to assemble the pinion gear shaft in the differential case so as to be movable in the axial direction, the case is provided with an axial long hole through which the shaft penetrates, and the pinion gear is eccentric to the shaft. The eccentric ring of the same gear is rotatably fitted so as to be assembled via the hole, and the eccentric ring is newly adopted. Therefore, the conventional pinion gear shaft and side gears can be used as they are, but the differential case and pinion gear can be used with slight holes, and the power distribution device can be used with minimal changes to the conventional components and eccentricity. Only a new ring is required, which is extremely economically advantageous.

(Embodiment) The present invention will be described below with reference to the drawings. FIG. 1 shows a power distribution device according to a first embodiment of the present invention. The power distribution device is used as a center differential of a power transmission device for a four-wheel drive vehicle, as shown in FIG.

The power transmission device includes a transmission 20, a center differential 30, a front differential 40, and a direction changing mechanism 50 housed in a case 11, and the transmission 20 is assembled to one side of the engine via a clutch mechanism 12. The transmission 20 includes an input shaft 21, an output shaft 22, and respective speed change gear units, and an output gear 23 on the output shaft 22.

The center differential 30 includes a differential case 31, a plurality of pinion gears 32, a pinion gear shaft 33, and a pair of side gears 34, 35, and a ring gear 36 on the outward flange portion of the differential case 31. Ring gear
36 meshes with the output gear 23 of the transmission 20 and transmits the power output from the transmission 20 to the differential case 31. Front differential 40 and direction changing mechanism 50 are center differentials
The front differential 40 is arranged coaxially with respect to 30, and the front differential 40 is a mount case constituting a direction changing mechanism 50.
It is housed within 51.

The front differential 40 includes a differential case 41, a plurality of pinion gears 42, and a pair of side gears 43, 44. The differential case 41 is connected via a hollow shaft 45 to the left side gear 34 of the center differential 30 so that torque can be transmitted. Such front differential 40
, The hollow shaft 45 and the side gear shaft 13a that rotatably penetrates the left end of the case 11 to the left side gear 43, and the side gear shaft 13b that rotatably penetrates the right end of the differential case 41 and the case 11 to the right side gear 44 respectively. It is communicatively linked. The direction changing mechanism 50 includes a ring gear 52 assembled to the outward flange portion of the mount case 51, and a sleeve 53 that connects and disconnects the case 51 and the differential case 41 of the front differential 40. Mount case 51 is the right side gear of the center differential 30.
Torque transmission is connected to the hollow shaft portion of 35, and the ring gear 52 meshes with the pinion shaft 54. The pinion shaft 54 is connected to the rear wheel side propeller shaft.

In the power transmission device having such a configuration, the power from the engine is transmitted to the center differential 30 through the output gear 23 and the ring gear 36 of the transmission 20.
Of the pinion gear 32
Is distributed to each side gear 34, 35. Left side gear
The power distributed to 34 is transmitted to the front differential 40 and output to the front wheel side, and the power distributed to the right side gear 35 is transmitted to the direction changing mechanism 50 and output to the rear wheel side.

In the center differential 30, as shown in FIG. 1, a plurality of elongated holes 31b extending in the axial direction of the side gears 34, 35 are formed in the main body 31a of the differential case 31, and the pinion gear shaft 33 is formed in each elongated hole 31b. Each shaft portion 33a has side gears 34, 3 as shown in FIG. 3 and FIG.
It is assembled so that it can move along the 5 axis direction. Further, each pinion gear 32 is assembled to each shaft portion 33a of the pinion gear shaft 33 via an eccentric ring 37 as shown in FIGS. Each pinion gear 32 is rotatably attached to each eccentric ring 37.
The distance between the meshing portions of the side gears 34 and 35 of the pinion gear 32 is L, the distance between the axial center of the pinion gear shaft 33 and the meshing portion of the left side gear 34 is Lf, and the distance between the meshing portion of the right side gear 35 is Lr. In this case, the shaft center of the pinion gear shaft 33 is deviated from the meshing portion of the side gears 34, 35 as shown in FIGS. 1 and 4. The pinion gear shaft 33 is connected to a sleeve 38a that is axially slidably mounted on the outer periphery of the main body 31a of the differential case 31, and is externally operated (for example, hydraulic pressure, vacuum, etc.) via a sleeve yoke 38b that engages with the sleeve 38a. It is possible to move along the long hole 31b. In the center differential 30 having such a configuration, power from the engine is transmitted to the side gears 34, 35 via the differential case 31, the pinion gear shaft 33, the eccentric ring 37, and the pinion gear 32, but in this case, the side gears 34, 35 (front wheel side, The power distribution ratio to the rear wheels is Lf / L and Lr / L. Then, the side gear 34,
When an attempt is made to move the shaft 35 in the axial direction, the differential case 31, the pinion gear shaft 33, the eccentric ring 37, the pinion gear 32, and the side gears 34, 35 relatively rotate about the shaft centers of the gears 34, 35. As a result, the pinion gear shaft 33 also moves in the axial direction of the side gears 34 and 35, and the distances Lf and Lr between the axial center of the pinion gear shaft 33 and the meshing portions of the side gears 34 and 35 change. Therefore, the power distribution ratios Lf / L and Lr / L to the front and rear wheels are determined by the pinion gear shaft 33
If the amount of movement changes appropriately according to the running state of the vehicle and the coefficient of friction of the road surface,
Power distribution to the front and rear wheels can be controlled to an appropriate value.

By the way, in the center differential 30, the conventional components are adopted and the long hole 31 is formed in the differential case 31.
b) The pinion gear 32 is provided with a hole for fitting the eccentric ring 37, and the eccentric ring 37 is only newly adopted. It is advantageous.

FIG. 5 shows a center differential 30A which is a power distribution device according to a second embodiment of the present invention. The center differential 30A is largely different from the center differential 30 of the first embodiment in that the eccentric ring 37A has a ring whose outer periphery forms a part of a spherical surface (hereinafter referred to as a spherical shape), and is different. With the adoption of the eccentric ring 37A, the outer side of the inner hole of each pinion gear 32A is formed into a spherical shape corresponding to the ring 37A, and the ring 37A is a compression spring at the step portion of the cylindrical portion 33b of the pinion gear shaft 33A. The difference is that it is elastically supported via 38c.

Therefore, in such a center differential 30A, when the side gears 34, 35 of the pinion gear shaft 33A are moved in the axial direction, the same pinion gear shaft 33A is used.
During relative rotation with respect to each pinion gear 32A about the axis of each eccentric ring 37A, since each eccentric ring 37A is rotatable with respect to each pinion gear 32A, the inclination of the axis of each ring 37A and pinion gear shaft 33A is always uniform. However, the axial movement restriction of the pinion gear shaft 33A caused by the rotation restriction of each eccentric ring 37A by each pinion gear 32A is eliminated.

[Brief description of drawings]

FIG. 1 is a sectional view of a center differential that is a first embodiment of a power distribution device according to the present invention, FIG. 2 is a schematic configuration diagram of a power transmission device adopting the differential, and FIG. 3 is an arrow in FIG. A sectional view taken along line III-III, FIG. 4 is a sectional view taken along line IV-IV in FIG. 1, and FIG. 5 is a sectional view of a center differential which is a second embodiment of the power distribution device according to the present invention. Is. Explanation of code 20 …… Transmission, 30, 30A …… Center differential, 31 …… Differential case, 32,32A …… Pinion gear, 33,33A …… Pinion gear shaft, 34,35…
… Side gear, 36 …… Ring gear, 37,37A …… Eccentric ring, 38a …… Sleeve, 38c …… Compression spring, 40…
… Front differential, 50… Direction changing mechanism.

Claims (1)

[Claims] 1. A differential case that rotates at the output of a transmission,
A plurality of pinion gears rotatably mounted on the pinion gear shaft mounted in this case and housed in the same case, and a plurality of pinion gears rotatably mounted in the case and meshing with the respective pinion gears and front wheel side And a pair of side gears respectively connected to the rear wheel side so that torque can be transmitted, and the pinion gear shaft is assembled to the case so as to be movable by a predetermined amount in the axial direction of the side gear by an external operation, and the pinion gear is A power distribution device for front and rear wheels, which is rotatably attached to the pinion gear shaft via an eccentric ring.