JPH09280339A - Differential gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase of a manufacturing cost and to prevent the occurrence of deterioration with age of a torque bias ratio by a method wherein an annular protrusion part to increase the outside diameter of the frictional contact surface of a side gear. SOLUTION: The end parts on the outside of a pair of side gears 3A and 3B are extended to further the outside than planetary gears 4A and 4B and annular protrusion parts 34A and 34B are formed thereat. Further, recessed parts 35A and 35B having diameters larger than those of spline holes 30A and 30B are formed at the central parts of the end faces 33A and 33B on the outside of side gears 3A and 3B, respectively. Thus, the outside diameters of the end faces 32A and 32B on the outside of the side gears 3A and 3B are increased to a value higher than the outside diameter by a amount equivalent to the sizes of protrusion parts 34A and 34B. Further, the inside diameters of the end faces 33A and 33B are increased to a value higher than the inside diameter of the outer end face by an amount equivalent to the sizes of the recessed part 35A and 35B. This constitution prevents the increase of a manufacturing cost and deterioration with age of a torque bias ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential gear device including a pair of side gears having helical teeth and at least a pair of planetary gears that mesh with each side gear and mesh with each other.

[0002]

2. Description of the Related Art Generally, in this type of planetary gear device, a friction contact surface is formed on the outer or inner end surface of a side gear, and the friction contact surface of each side gear is pressed into contact with the housing or the other side gear. It is like this. Therefore, when the pair of side gears rotates relative to the housing, frictional resistance is generated between the side gears and the housing or another side gear, and torque based on this frictional resistance (hereinafter referred to as friction torque) is generated. Thus, different magnitudes of torque are transmitted to the pair of side gears (hereinafter, the ratio of the torque transmitted to the pair of side gears is referred to as the torque bias ratio).

Incidentally, in the conventional differential gear device, various improvements have been made in order to increase the torque bias ratio. For example, a plurality of friction washers may be arranged between the side gear and the housing (actually open shovel 61-1).
23250), or increasing the friction coefficient of the friction resistance surface.

[0004]

However, when a plurality of friction washers are used, there is a problem that the number of parts increases and the manufacturing cost of the apparatus rises accordingly. Further, in the case of increasing the friction coefficient of the friction resistance surface, there is a problem that when the friction resistance surface wears, the friction coefficient changes accordingly, and as a result, the torque bias ratio changes with time.

[0005]

The present invention has been made to solve the above problems, and the invention according to claim 1 is such that a housing driven to rotate and an axis of the housing coincides with an axis of the housing. And a pair of side gears having torsion teeth rotatably and movably supported,
The housing is rotatably supported and includes at least a pair of planetary gears that mesh with the pair of side gears and mesh with each other, and a frictional contact surface that contacts the housing or another side gear is formed on an end surface of the side gear. The differential gear device is characterized in that an annular protrusion is formed at the end of the side gear in order to increase the outer diameter of the friction contact surface of the side gear. According to a second aspect of the present invention, there is provided a housing which is rotatably driven, a pair of side gears having torsion teeth which are rotatably and movably supported by the housing such that an axis line thereof coincides with an axis line of the housing, and the housing includes A differential that is rotatably supported and includes at least a pair of planetary gears that mesh with the pair of side gears and mesh with each other, and that has a frictional contact surface that is in contact with the housing or another side gear at an end surface of the side gear. In the gear device, in order to increase the inner diameter of the friction contact surface of the side gear, a concave portion is formed in the center of the end surface of the side gear. According to a third aspect of the present invention, there is provided a housing which is rotatably driven, a pair of side gears having torsion teeth which are rotatably and movably supported by the housing such that an axis of the housing coincides with an axis of the housing. A differential that is rotatably supported and includes at least a pair of planetary gears that mesh with the pair of side gears and mesh with each other, and that has a frictional contact surface that is in contact with the housing or another side gear at an end surface of the side gear. In the gear device, in order to increase the outer diameter of the friction contact surface of the side gear,
An annular protrusion is formed at the end of the side gear, and a recess is formed at the center of the end of the side gear in order to increase the inner diameter of the friction contact surface of the side gear. In the invention according to claim 1, it is desirable that the protruding portion is formed at an outer end portion of the side gear. In the invention according to claim 3, the protrusion may be formed on the outer end of the side gear, and the recess may be formed on the outer end surface of the side gear. The recess may be formed on the inner end portion, and the recess may be formed on the inner end surface of the side gear. In this case, it is desirable that the twisting directions of the pair of side gears be different from each other.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying FIG. 1 is a sectional view showing a differential gear device 1 according to the present invention. The differential gear device 1 includes a housing 2 that is driven to rotate about an axis L. The housing 2 includes a cylindrical body 2A having a bottom portion 21 at one end and a lid body 2B that closes the other end opening of the cylindrical body 2A.
Bearing holes 22 and 22 penetrating the central portion 1 and the central portion of the lid 2B are formed. Each bearing hole 2
A pair of output shafts (not shown) are rotatably inserted through the shaft 2.

Inside the housing 2, a pair of side gears 3A, 3B are rotatably and movably arranged with their axes aligned with the axis L. At the center of each side gear 3A, 3B, a spline hole 30A,
30B are formed and each spline hole 30A, 30 is formed.
The inner ends of the pair of output shafts located inside the housing 2 are connected to B so as to be non-rotatable and axially movable. Further, gear parts 31A and 31B having torsion teeth are provided on the outer circumferences of the inner ends of the pair of side gears 3A and 3B.
Are formed respectively. Although the twisting directions of the gear parts 31A and 31B are arbitrary, different twisting directions are adopted here.

Inside the housing 2, at least one pair (usually three or four pairs) of planetary gears 4A, 4B are provided.
The planetary gear 4B (not shown) is rotatably arranged with its axis parallel to the axis L. The planetary gear 4A has a long gear portion 41 and a short gear portion 42 at one end portion and the other end portion, and the long gear portion 41 and the short gear portion 42 are connected by a neck portion 43. Planetary gear 4A (4
The long gear portion 41 of B) meshes with one of the side gears 3A (3B) at the end portion on the neck portion 43 side, and meshes with the short gear portion 42 of the planetary gear 4B (4A) at the outer end portion. The short gear portion 42 of the planetary gear 4A (4B) meshes with the long gear portion 41 of the planetary gear 4B (4A) at its outer end portion.

Since the pair of side gears 3A, 3B and the pair of planetary gears 4A, 4B have torsion teeth, when the housing 2 is driven to rotate, the side gears 3A, 3B.
Axial thrust force generated by the meshing with the planetary gears 4A and 4B acts on. Particularly, in the planetary gear device 1, since the twisting directions of the side gears 3A and 3B are different from each other, when the housing 2 is rotationally driven in one direction, the thrust force F _R1 , which is directed outward toward the side gears 3A and 3B, When F _L1 acts and the housing 2 is rotationally driven in the other direction, the side gears 3A, 3
Thrust forces F _R2 and F _L2 directed inwardly act on B. Then, the thrust forces F _R1 and F _L1 are applied to the side gears 3A and 3A.
Outer end face of the B (frictional resistance surface) 32A, 32B is pressed against the housing 2, the thrust force F _R2, F _L2 by side gears 3A, the inner end surface of 3B (frictional resistance surface) 33
A and 33B are pressed against the thrust washer 5. The thrust washer 5 is prevented from rotating by the planetary gears 4A and 4B and rotates together with the housing 2.

The outer ends of the pair of side gears 3A and 3B extend to the outside of the planetary gears 4A and 4B,
Annular protrusions 34A and 34B are formed there. Therefore, the outer end surface 3 of the side gears 3A, 3B is
The outer diameters of 2A and 32B are larger than the outer diameter of the outer end surface of the conventional side gear by the amount that the protruding portions 34A and 34B are formed.

Further, spline holes 30A, 3 are provided at the central portions of the outer end faces 33A, 33B of the side gears 3A, 3B.
Recesses 35A and 35B having a diameter larger than 0B are formed. Therefore, the end faces 33 of the side gears 3A and 3B are
The inner diameters of A and 33B are larger than the inner diameter of the outer end surface of the conventional side gear by the amount that the recesses 35A and 35B are formed.

In the differential gear device 1 having the above structure, the side gear 3 is provided when the housing 1 is rotating in one direction.
When A and 3B are differentially rotated, frictional resistances F _R1 and F _L1 are generated between the side gears 3A and 3B and the housing 2, and a friction torque based on the frictional resistances acts on the side gears 3A and 3B. In this case, since the outer diameter and inner diameter of the end surfaces 32A and 32B are larger than the outer diameter and inner diameter of the end surface of the conventional differential gear device, a larger friction torque acts on the side gears 3A and 3B. Therefore, the torque bias ratio can be increased as compared with the conventional differential gear device.

Particularly, in this differential gear device 1, since the projecting portions 34A and 34B are formed at the outer end portions of the side gears 3A and 3B, they are arranged outside them so as not to interfere with the planetary gears 4A and 4B. can do. Therefore, the outer diameter of the protrusions 34A and 34B can be increased. Therefore, the torque bias ratio can be further increased. Moreover, by forming the protrusions 34A, 34B on the side gears 3A, 3B, the side gear 3
Since the outer diameters of the outer end surfaces of A and 3B can be increased, the inner diameters of the recesses 3A and 3B can be increased as compared with the case where the recesses 35A and 35B are formed on the inner end surfaces of the side gears 3A and 3B. it can. Therefore, the torque bias ratio can be further increased.

The protrusions 34A, 34B and the recess 3 are also provided.
Since only 5A and 35B are formed, the number of parts does not increase and therefore the manufacturing cost can be kept low. Moreover, the end faces 32A, 32B, which are frictional contact faces,
Since the magnitude of is the same even when worn, the torque bias ratio does not change over time.

Further, in this differential gear device 1,
Since the torque bias ratio when the housing 1 rotates in one direction can be increased, the difference between the torque bias ratio when the housing 1 rotates in one direction and the torque bias ratio when the housing 1 rotates in the other direction is reduced. be able to. That is, the outer end surfaces 32A, 32 of the side gears 3A, 3B
Assuming that the inner and outer diameters of B and the inner end surfaces 33A and 33B are the same, when the housing 2 rotates in one direction and thrust forces F _R1 and F _L1 are generated, and when the housing 2 moves in the other direction. The torque bias ratio of the former is smaller than the torque bias ratio of the latter in the case where the thrust forces F _R2 and F _L2 are generated by rotation. However, in the case of the differential gear device 1, since the protrusions 34A and 34B and the recesses 35a and 35b are formed at the outer ends of the side gears 3A and 3B, the former torque bias ratio can be increased. it can. Therefore, it is possible to make the torque bias ratio the same when the housing 2 rotates in one direction and the case where the housing 2 rotates in the other direction, or reduce the difference.

On the contrary, the protrusions 34A, 34B and the recess 3
When 5A and 35B are formed at the inner ends of the side gears 3A and 3B, the difference in torque bias ratio between the rotation of the housing in one direction and the rotation in the other direction can be further increased. . Of course, also in this case, the twisting directions of the side gears 3A and 3B are set to be opposite to each other.

The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, in the differential gear device 1 described above, the planetary gears 4A,
Although 4B is arranged parallel to the axis L, it may be arranged to be orthogonal to the axis L. In addition, the differential gear device 1 described above
In the above, both the outer diameter and the inner diameter of the outer end surfaces 32A, 32B are made larger, but only one of them may be made larger, and instead of the outer end surfaces 32A, 32B, the inner end surfaces 33A, 33B. The outer diameter or the inner diameter may be increased. In this case, the side gears 3A, 3
If the twisting direction of B is the same as that of the differential gear device 1 described above,
It is possible to further increase the difference in the magnitude of the torque bias ratio when the housing 2 is rotated in one direction and the other direction. Alternatively, the outer end surfaces 32A, 32B
The outer diameter or the inner diameter of both of the inner end surfaces 33A and 33B may be increased. Furthermore, the side gears 3A, 3B
Although the inner end surfaces 33A and 33B are brought into contact with the washer 5 which is non-rotatably provided in the housing 1, they may be brought into direct contact with each other.

[0018]

As described above, according to the inventions according to claims 1 to 3, the torque bias ratio can be increased, and the manufacturing cost rises or the torque bias ratio is increased. The effect that it is possible to prevent the change over time is obtained. According to the inventions according to claims 4 to 6, the effect that the torque bias can be further increased is obtained. According to the invention of claim 7, the difference between the torque bias ratios when the housing rotates in one direction and when the housing rotates in the other direction is increased,
Alternatively, an effect that it can be reduced can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a differential gear device according to the present invention.

[Explanation of symbols]

 L axis 1 Differential gear device 2 Housing 3A Side gear 3B Side gear 4A Planetary gear 32A Outer end face (friction resistance face) 32B Outer end face (friction resistance face) 33A Inner end face (friction resistance face) 33B Inner end face (friction resistance) Surface) 34A Annular protrusion 34B Annular protrusion 35A Recess 35B Recess

Claims (7)

[Claims] 1. A housing driven to rotate, a pair of side gears having torsion teeth rotatably and movably supported by an axis of the housing aligned with an axis of the housing, and rotatable to the housing. A differential gear device in which a frictional contact surface that is in contact with the housing or another side gear is formed on an end surface of the side gear, the planetary gear being supported by the pair of side gears, and at least a pair of planetary gears that mesh with each other. A differential gear device characterized in that an annular protrusion is formed at an end of the side gear in order to increase an outer diameter of a friction contact surface of the side gear. 2. A housing driven to rotate, a pair of side gears having torsion teeth rotatably and movably supported by the housing so that its axis coincides with the axis of the housing, and the housing is rotatable to the housing. A differential gear device in which a frictional contact surface that is in contact with the housing or another side gear is formed on an end surface of the side gear, the planetary gear being supported by the pair of side gears, and at least a pair of planetary gears that mesh with each other. A differential gear device characterized in that a recess is formed in a central portion of an end face of the side gear in order to increase an inner diameter of a friction contact surface of the side gear. 3. A housing driven to rotate, a pair of side gears having torsion teeth rotatably and movably supported by an axis of the housing aligned with the axis of the housing, and rotatable to the housing. A differential gear device in which a frictional contact surface that is in contact with the housing or another side gear is formed on an end surface of the side gear, the planetary gear being supported by the pair of side gears, and at least a pair of planetary gears that mesh with each other. In order to increase the outer diameter of the friction contact surface of the side gear, an annular protrusion is formed at the end of the side gear,
A differential gear device characterized in that a recess is formed in a central portion of an end face of the side gear in order to increase an inner diameter of a friction contact surface of the side gear. 4. The differential gear device according to claim 1, wherein the protruding portion is formed at an outer end portion of the side gear. 5. The differential gear device according to claim 3, wherein the protruding portion is formed on an outer end portion of the side gear, and the recess is formed on an outer end surface of the side gear. 6. The differential gear device according to claim 3, wherein the protruding portion is formed on an inner end portion of the side gear, and the recess is formed on an inner end surface of the side gear. 7. The twisting direction of the pair of side gears is different from each other.
The differential gear device according to.