JPH04140539A - Differential gear - Google Patents

Abstract

PURPOSE:To produce a differential device which is simple and has differential limiting function by providing the first member with an external cam face, the second member with an external and an internal tooth, the third member which has an internal tooth and establishes the second member to be rotatable and revolvable, and the fourth member which has an external tooth and is made rotatable. CONSTITUTION:A differential device P, for instance, uses the third member 3 as an input member, and the first member 1 and the fourth member 4 as an output member respectively. In this case, torque rotational transmission is executed from the third member 3 to the first member 1 and the fourth member 4 for displaying differential function as the second member 2 rotates and, in addition to that, revolves. The torque rotational transmission from the second member 2 to the first member 1 is executed through an eccentric cam formed by utilizing an external cam face 5A and an internal cam face 5B. Since the sliding areas of both the cam faces 5A, 5B are extremely wide, strong frictional force can be obtained to produce differential limiting function.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a differential device.

(Prior Art) A drive system of an automobile is equipped with a differential device in order to absorb the difference in rotation between the left and right axes or the difference in rotation between the front and rear wheels. In this differential device, when the load on one output side becomes small or disappears, torque is no longer transmitted to the other output side, making it impossible to escape from mud or the like.

For this reason, a differential limiting device for limiting the differential function is added to the differential to create a so-called non-slip differential.

However, conventional differential limiting devices, for example,
As shown in Japanese Patent No. 1-71527, the number of parts is quite large and the structure is complicated, and countermeasures are desired in this respect.

(Object of the invention) The present invention has been made in consideration of the above circumstances, and
It is an object of the present invention to provide a differential device having an extremely simple structure and having a differential limiting function.

(Structure, operation, and effect of the invention) In order to achieve the above object, the present invention has the following structure. That is, a first member that is rotatable about a first axis and has a circular outer cam surface that is centered about a second axis eccentric from the first axis; and a first member that slides with respect to the outer cam surface. a second member having an inner cam surface which is rotatably fitted while being rotatable, and a second member having external teeth and internal teeth each centered on the second axis; a third member having internal teeth configured to allow the second member to rotate and revolve; and a third member having external teeth that mesh with the internal teeth formed on the second member, and configured to allow the second member to rotate on its own axis. and a fourth member that is made possible.

In the differential device configured in this manner, the third member is used as an input member, and the first member and the fourth member are used as output members, respectively. At this time, while the second member rotates and revolves, rotation is transmitted from the third member to the first member and the fourth member, thereby performing a differential function.

Torque (rotation) is transmitted from the second member to the first member via an eccentric cam that utilizes an outer cam surface and an inner cam surface. Since the sliding area between both cam surfaces is extremely large, a large frictional force is obtained, and this large frictional force provides a differential limiting function.

As described above, according to the present invention, a differential device having a differential limiting function can have a reduced number of parts as a whole and can be made simple in structure.

(Example) Examples of the present invention will be described below based on the attached drawings.

1 and 2, the differential device P according to the present invention is
It includes a first member 1, a second member 2, a third member 3, and a fourth member 4.

The first member 1 is rotatable about a first axis I21, and an outer cam surface 5A is formed on the first member 1. The outer cam surface 5A has a circular outer circumferential shape,
Its center is a second axis β2 eccentric with respect to the first axis 21.
It is set to be located at the top.

The second member 2 has an inner cam surface 5B, outer teeth 6, and inner teeth 7. The inner cam surface 5B has a circular inner peripheral shape and is slidably fitted to the outer cam surface 5A. The two cam surfaces 5A and 5B constitute an eccentric cam eccentric to the first axis I21. In addition, external teeth 6 and internal teeth 7
are formed centering on the second axis I22, respectively.

The third member 3 is annular and has internal teeth 8 formed therein. This internal tooth 8 is the first axis #! in the embodiment. It is formed around a1, and the external teeth 6 of the second member 2 mesh with each other.

The number of teeth of the internal teeth 8 is sufficiently larger than the number of teeth of the external teeth 6 (so that the second member 2 can revolve and rotate relative to the third member 4.

External teeth 9 are formed on the fourth member 4 , and the external teeth 9 mesh with the internal teeth 7 of the second member 2 . In the embodiment, the outer teeth 9 are set so that their centers are located on the first axis I21, and the number of teeth is sufficiently smaller than the number of teeth of the internal teeth 7 (so that the fourth member 4 is located on the first axis I21). It is designed to be able to rotate around an axis 21.

Next, the operation of the above configuration will be explained.

Now, consider a case where the third member 3 is used as an input member for engine torque, and the first member 1 and the fourth member 4 are used as output members to the left and right drive wheels, respectively. Note that the third member 3 may be formed with external teeth for input, for example, in order to receive the rotational force due to the engine torque. Also, the number of teeth of internal teeth 8 is Zl
, the number of external teeth 6 is Z2, the number of internal teeth 7 is z3, and the number of external teeth 9 is 74.

Under the above premise, if the first member 1 is rotated once in a predetermined direction with the third member 3 fixed, the second member 2 rotates inside the third member 3 in the opposite direction (Z 1 −
Z2)/22 minutes. Therefore, the fourth member 4 is rotated by I2 I4. Note that when the value of the above formula is 1j, it is equal torque distribution, and when it is other than NJ, it is division torque distribution.

As is clear from the above description, it is clear that it has a differential function. Then, the first member l has cam surfaces 5A, 5
Since it is connected to the second member 2 with a large frictional force using B, it also has a differential limiting function. In order to make this kind of differential limiting function more effective, it is recommended that each tooth be a helical gear (increase in frictional force).

FIG. 3 shows an example in which the aforementioned differential device is used as a center differential interposed between the front and rear wheels of an automobile.

In this Fig. 3, FD is a front wheel differential device, and 2
0 is the output shaft of the transmission. In the differential device P according to the present invention, the third member 3 is an input member that receives rotation from the output gear 21 of the transmission output shaft 20, the first member 1 is an output member for rear wheels, and the fourth member 4 is used as the output member for the front wheels. That is, the rotation of the first member 1 is transmitted to the rear wheel drive propeller shaft 27 via the gear 22.23, the shaft 24, and the gear 25.26. Further, the left and right output shafts 28 and 29 of the front wheel differential device FD are the first axis! A fourth member 4 is located on top of the second member 2 and serves both as a differential case of the front wheel differential device FD and as a holding member that rotatably holds the second member 2.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the present invention. FIG. 2 is a simplified exploded perspective view of FIG. 1. FIG. 3 is a sectional view showing an example in which the differential device according to the present invention is used as a center differential. P: Differential device 21: First axis I22: Second axis 1: First member 2: Second member 3: Third member 4: Fourth member 5A: Outer cam surface 5B: Inner cam surface 6 external teeth 7 : Internal teeth 8: Internal teeth 9: External teeth Patent applicant Mazda Motor Corporation representative Patent attorney Mura 1) Jitsuma Patent attorney Tadashi Hirai

Claims (1)

[Claims] (1) A first member that is rotatable about a first axis and has a circular outer cam surface that is centered about a second axis that is eccentric to the first axis, and that slides against the outer cam surface. a second member having an inner cam surface that is rotatably fitted while moving, and external teeth and internal teeth each centered on the second axis; and a second member that is rotatable and meshes with the external teeth of the second member. a third member having internal teeth set so that the second member can rotate and revolve; and external teeth meshing with the internal teeth formed on the second member; A differential device comprising: a fourth member that is rotatable on its axis.