JP2000136866A - Parallel shaft differential gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To incorporate another differential gear device in a parallel shaft differential gear device. SOLUTION: Long gear parts 31, 31 of respective planet gears 3A, 3B are threadly geared with short gear parts 32, 32 of other planet gears 3B, 3A in the inside parts 31b, 31b and with gear parts 2a, 2b of side gears 2A, 2B in the outside parts 31a, 31b. Neck parts 33, 33 of the planet gears 3A, 3B are arranged in a same position in the rotation axis L direction. A differential gear mechanism C is provided between side gears 2A, 2B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel shaft differential gear device in which a planet gear is arranged in parallel with a rotation axis of a housing.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a parallel shaft differential gear device includes a housing (not shown) that is driven to rotate about a rotation axis L, and an axis in the housing. A pair of side gears S ₁ and S ₂ rotatably supported in alignment with each other, and at least a pair of planet gears P ₁ and P ₂ rotatably provided in the housing in parallel with the rotation axis L. I have. Planet gear P
₁ and P ₂ have a long gear portion (first gear portion) Pa at one end.
, A short gear portion (second gear portion) Pb at the other end, and a neck portion Pc having a smaller diameter than the gear portions Pa and Pb at an intermediate portion.
Long gear portion Pa of one of the planet gears _{P 1} meshes with one side gear _{S 1} at its inner portion Pa _1,
Meshes with the short gear portion Pb of the other planet gear _{P 2} in the outer portion Pa _2. The other planet gear P
Long gear portion Pa of the ₂ meshes with the side gears _{S 2} other in the inner part Pa _1, one planet short gear portion of the gear _{P 1} meshes with Pa ₂ (Kohyo outside portion Pa ₂ 7-501870 Reference).

The above-described parallel shaft differential gear device is often used as a center differential of a four-wheel drive vehicle. In a four-wheel drive vehicle, in addition to the center differential, two different types of front differential and rear differential are provided. A differential gearing is used. Usually, the parallel shaft differential gear unit and the other two differential gear units are separately installed, and installation of each differential gear unit requires a great deal of labor. Therefore, it has been considered that one of the two differential gear devices is incorporated in the parallel shaft differential gear device. By doing so, only two differential gear devices need to be installed, and the labor required for installation can be reduced.

[0004]

In the case where another differential gear device is built in the parallel shaft differential gear device, the differential gear device is arranged on the rotation axis L between the pair of side gears S ₁ and S _2. However, in order to do so, the distance between the side gears S ₁ and S ₂ must be increased, and the length of the neck Pc of the planet gears P ₁ and P ₂ must be correspondingly increased. However, when the neck Pc is lengthened, the strength of the planet gears P ₁ and P ₂ is reduced, and there is a possibility that the planet gears P ₁ and P ₂ may be broken from the neck Pc. For this reason, it was not possible to incorporate another differential gear device into the parallel shaft differential gear device. The present invention has been made in view of the above circumstances, and has as its object to provide a parallel shaft differential gear device incorporating another differential gear device while minimizing the reduction in the strength of the planet gear. I have.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a housing that is driven to rotate about a rotation axis, and a rotatably supported housing having the axis aligned with the rotation axis. A pair of side gears, and at least a pair of planet gears rotatably supported by the housing in parallel with the rotation axis, and the pair of planet gears are provided at both ends thereof with first and second gears. The first gear portion of each planet gear meshes with each gear portion of the pair of side gears, while the other gear portion has a neck portion having a smaller diameter than the first and second gear portions at each intermediate portion. In the parallel shaft differential gear device that meshes with the second gear portion of the planet gear, at least a part of the gear portions of the pair of side gears may be combined with the first gear portion and the first gear portion. Outside from the meshing portion between the second gear portion meshing with said first gear portion, is characterized in that a differential gear mechanism to one of the side gears and the rotary drive source between the pair of side gears. In this case, the differential gear mechanism includes a support shaft that rotates integrally with one side gear in a longitudinal direction in a direction orthogonal to the rotation axis, a bevel gear rotatably supported by the support shaft, A pair of bevel gears rotatably arranged on the rotation axis and meshing with the bevel gear can be provided. The second gear portion of each planet gear meshes with the first gear portion of the other planet gear at an intermediate portion thereof, and the pair of side gears has an inner gear portion and an outer gear portion at both ends as the gear portions. The inner gear portion meshes with the first gear portion inside a meshing portion between the second gear portion and the first gear portion, and the outer gear portion is formed with the second gear portion. It is desirable that the gear meshes with the outside of the meshing portion with the first gear portion. The entire gear portion of each of the side gears is disposed outside the first gear portion outside the meshing portion between the first gear portion and the second gear portion.
It is desirable to mesh with the gear portion of the first embodiment. The gear portions of the pair of side gears may have the same outer diameter, or may have different outer diameters.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment of the present invention. The parallel shaft differential gear device A of this embodiment is suitable for use as a center differential and a rear differential or a center differential and a front differential of a four-wheel drive vehicle.
And a differential gear mechanism C called an open differential provided therein.

First, the parallel shaft differential gear mechanism B will be described. The parallel shaft differential gear mechanism B has a housing 1 which serves as a housing for the entire parallel shaft differential gear device A. The housing 1 includes a main body 11 having a bottomed cylindrical shape, and a lid 12 closing one end (the left end in FIG. 1) of the main body 11, and is rotated by an engine (not shown). It is driven to rotate about the axis L.

One end (left end in FIG. 1) and the other end inside the housing 1 have a pair of side gears 2A, 2A.
B is rotatably arranged with its respective axes coinciding with the rotation axis L. In the center of each of the side gears 2A and 2B, through holes 21 and 22 extending on the rotation axis L are formed, respectively. The side gear 2A has a gear portion 2a at an outer end and a support cylinder portion 24 having a circular cross section at an inner end, and is supported by the housing 1 via a planet gear 3A described later. The side gear 2B has a gear portion 2b at an inner end and an output cylinder portion 23 at an outer end. And, the output cylinder 23 is the main body 1
The housing 1 is rotatably supported by being rotatably fitted into the first support hole 13. Output cylinder 23
Is connected as an input shaft to a rear differential when the differential gear device A is used as a center and a front differential, and is connected as an input shaft to a front differential when used as a center and a rear differential.

Inside the housing 1, at least one pair of planet gears 3A and 3B are arranged.
Usually, three or four pairs of planet gears 3A and 3B are arranged. In this differential gear device A, three pairs are arranged.
In each of the planet gears 3A and 3B, a long gear portion (first gear portion) 31 is formed at one end, a short gear portion (second gear portion) 32 is formed at the other end, and a neck portion 33 is formed at an intermediate portion. ing. The length of the long gear portion 31 is slightly longer than the sum of the length of the gear portion 2a (2b) and the length of the short gear portion 32 of the side gear 2A (2B). The outer diameter of the neck 33 is
The diameter of the gear roots 31 and 32 is equal to or slightly smaller than the tooth bottom circle diameter.

A pair of planet gears 3A and 3B are rotatably supported in the housing 1 in parallel with the rotation axis L. One planet gear 3A is arranged with its long gear portion 31 located on the side gear 2A side, and the other planet gear 3B is arranged with its long gear portion 31 located on the side gear 2B side. I have.
The necks 33 of both planet gears 3A, 3B are located at the same position in the direction of the rotation axis L.

Long gear portion 31 of one planet gear 3A
Is engaged with the gear portion 2a of the side gear 2A at the outer portion 31a, and is engaged with the short gear portion 32 of the other planet gear 3B at the inner portion 31b. The long gear portion 31 of the other planet gear 3B meshes with the gear portion 2b of the side gear 2B at the outer portion 31a, and the one planet gear 3A at the inner portion 31b.
And the short gear portion 32 of the second gear. Therefore, the planet gears 3A, 3B are formed as a side gear 2A,
2B are connected.

Next, the differential gear mechanism C will be described. The support cylinder 24 of the side gear 2A has its axis aligned with the rotation axis L, and the distal end surface of the support cylinder 24 and the side gear 2B are connected to each other. A spacer 73 is arranged between the two. By the spacer 73, the side gear 2A,
Positioning in the direction of the rotation axis L of 2B is performed.

The casing 4 is disposed inside the support cylinder 24. The casing 4 has a hollow spherical portion 41.
And cylindrical portions 42, 42 formed integrally with the spherical portion 41 at one end and the other end on a straight line passing through the center of the spherical portion 41. The casing 4 is arranged such that the axes of the cylindrical portions 42 and 42 coincide with the rotation axis L. One cylindrical portion 42 passes through the through hole 21 of the side gear 2A, and is rotatably supported via a bush 71 in a support hole 14 formed in the center of the lid 12. The other cylinder 42 is
The housing 1 is rotatably fitted into the through hole 22 of the side gear 2B via a bush 72, and
It is supported rotatably.

A support shaft 5 orthogonal to the rotation axis L is disposed at the center of the spherical portion 41 of the casing 4. Both ends of the support shaft 5 penetrate the ball portion 41 and are connected to the support cylinder portion 24. Therefore, the support shaft 5 and the casing 4 rotate integrally with the side gear 2A.

Inside the casing 4, two pairs of bevel gears 6A, 6B, 6C and 6D are arranged. One pair of bevel gears 6A and 6B is rotatably supported by one end and the other end of the support shaft 5. The other pair of bevel gears 6
C and 6D are rotatably arranged with their respective axes coinciding with the rotation axis L. One pair of bevel gears 6A,
6B and the other pair of bevel gears 6C and 6D mesh with each other. That is, the bevel gear 6A meshes with the bevel gears 6C and 6D, and the bevel gear 6B also meshes with the bevel gears 6C and 6D.

Output shafts 61 and 62 extending on the rotation axis L are formed on the back surfaces of the bevel gears 6C and 6D, respectively. The output shaft 61 of the bevel gear 6C extends outside the housing 1 through the cylindrical portion 42 and the support hole 14, and if the differential gear device A is used as a center and a front differential, the left and right front wheels are provided. If the differential gear device A is used as a center and a rear differential, it is connected to one of the left and right rear wheels. The output shaft 62 of the bevel gear 6D extends outside through the output cylinder portion 23, and is connected to the other of the left and right front wheels or the other of the left and right rear wheels.

In the parallel shaft differential gear device A having the above structure, the gear portions 2a and 2b of the side gears 2A and 2B are replaced with the outer portions 3 of the long gear portions 31 and 31 of the planet gears 3A and 3B.
1a, 31a, that is, the short gears 32, 32 mesh with the long gears 31, 31 outside the meshing inner portions 31b, 31b, so that the side gears can be formed without elongating the neck 33. 2
The interval between A and 2B can be widened. as a result,
The spherical portion 41 of the casing 4 can be accommodated between the side gears 2A and 2B. The differential gear mechanism C is incorporated in the parallel shaft differential gear device A, and the center differential and the front differential are provided in one differential gear device A. Or it could have the functions of a center differential and a rear differential.

When the housing 1 is rotated in the case where the parallel shaft differential gear device A is used as a center differential and a front differential, the driving force of the engine is applied to the left and right front wheels via the output shafts 61 and 62. The power is transmitted to the rear differential via the output cylinder 23. When the average rotation speed of the left and right front wheels is different from the average rotation speed of the left and right rear wheels, torque is transmitted from the high speed rotation side to the low speed rotation side according to a predetermined torque bias ratio. This is the same when the differential gear device A is used as a center differential and a rear differential.

Next, another embodiment of the present invention will be described. In the following embodiments, only the configuration different from the above embodiment will be described, and the description of the same configuration as the above embodiment or the same configuration as the known parallel shaft differential gear device will be given. Omitted. The description and illustration of the differential gear mechanism C are also omitted.

FIGS. 2 and 3 show a second embodiment of the present invention. In this embodiment, the outer diameters of the pair of side gears 2A and 2B are different from each other by making the number of teeth, the torsion angle, the amount of displacement, and the like different from each other. In this embodiment, the side gear 2
Although the outer diameter of A is smaller than the outer diameter of side gear 2B, it may be reversed. When the outer diameters of the pair of side gears 2A, 2B are different, the torque transmitted from the housing 1 to the side gears 2A, 2B can be different. In FIG. 2, for convenience of illustration and description, the rotation axis L is divided into two parallel lines, and a pair of side gears 2A and 2B are drawn on each parallel line L.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, a side gear 2 </ b> A has an inner gear portion (gear portion) 21 formed at an end on the inner side (side gear 2 </ b> B side) of the housing 1 and an outer gear formed at an outer end of the housing 1. A gear portion (gear portion) 22;
The gear portions 21 and 22 have a smaller diameter than the root circle diameter, and are constituted by a small-diameter portion 23 formed therebetween at an intermediate portion. The inner gear portion 21 and the outer gear portion 22 of the side gear 2A mesh with the long gear portion 31 of the planet gear 3A at both ends. Similarly, the other side gear 2B also includes an inner gear portion 21, an outer gear portion 22, and a small-diameter portion 23. The inner gear portion 21 and the outer gear portion 22 mesh with the long gear portion 31 of the planet gear 3B at both ends thereof. ing. The short gear portions 32, 32 of the planet gears 2A, 2B mesh with the paired long gear portions 31, 31 of the planet gears 3B, 3A, respectively, at their intermediate portions. In the meshing state, the short gear portions 32, 32 face the side gears 2A, 2B. However, since the small-diameter portion 23 is formed at an intermediate portion between the side gears 2A, 2B, the short gear portions 32, 32 are formed.
Does not interfere with the side gears 2A, 2B.

In this embodiment, the side gear having the gear portion in which the inner and outer gear portions 21 and 22 are continuous is formed so as to mesh with the long gear portion 31 inside the meshing portion between the short gear portion 32 and the long gear portion 31. Compared with the case where the outer gear portion 22 is engaged, the interval between the side gears 2A and 2B can be increased by the amount that the outer gear portion 22 meshes with the long gear portion 31 outside the meshing portion between the short gear portion 32 and the long gear portion 31. it can.

[0023]

As described above, according to the present invention, the distance between the pair of side gears can be increased without reducing the strength of the planet gear, and as a result, the pair of side gears of the parallel shaft differential gear device can be obtained. The effect that another differential gear device can be built in between them is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a main part of a second embodiment of the present invention.

FIG. 3 is a view taken in the direction of the arrow X in FIG. 2;

FIG. 4 is a diagram showing a main part of a third embodiment of the present invention.

FIG. 5 is a diagram showing a main part of an example of a conventional parallel shaft differential gear device.

[Explanation of symbols]

 A Parallel shaft differential gear device L Rotation axis line 1 Housing 2A Side gear 2B Side gear 2a Gear portion 2b Gear portion 3A Planet gear 3B Planet gear 21 Inner gear portion (gear portion) 22 Outer gear portion (gear portion) 31 Long gear portion (first) 1 gear portion) 31a outer portion 31b inner portion 32 short gear portion (second gear portion) 33 neck portion

Claims (5)

[Claims] A housing rotatably driven about a rotation axis, a pair of side gears rotatably supported by the housing such that the axis coincides with the rotation axis, and a pair of side gears mounted on the housing in parallel with the rotation axis. And at least a pair of planet gears rotatably supported,
The pair of planet gears have first and second gear portions at both end portions, and a neck portion having a smaller diameter than the first and second gear portions at their respective intermediate portions. In the parallel shaft differential gear device in which the gear portion meshes with each gear portion of the pair of side gears and meshes with the second gear portion of the other planet gear, at least a part of the gear portion of the pair of side gears is A differential gear mechanism that meshes with the first gear portion outside a meshing portion between the first gear portion and the second gear portion and uses one side gear as a rotational drive source between the pair of side gears. A parallel-shaft differential gear device characterized by being arranged. 2. A support shaft, wherein the differential gear mechanism rotates integrally with one side gear in a longitudinal direction in a direction orthogonal to the rotation axis, and a bevel gear rotatably supported by the support shaft. The parallel shaft differential gear device according to claim 1, further comprising a pair of bevel gears rotatably arranged on the rotation axis and meshing with the bevel gear. 3. A second gear portion of each planet gear meshes with a first gear portion of the other planet gear at an intermediate portion thereof, and the pair of side gears serve as the gear portions at both ends thereof at an inner gear portion and an outer gear portion. A gear portion, wherein the inner gear portion meshes with the first gear portion inside a meshing portion between the second gear portion and the first gear portion,
3. The parallel shaft operating gear device according to claim 1, wherein the outer gear portion meshes outside a meshing portion between the second gear portion and the first gear portion. 4. 4. The whole gear portion of each of the side gears is meshed with the first gear portion outside a meshing portion between the first gear portion and the second gear portion. Item 3. The parallel shaft differential gear device according to item 1 or 2. 5. The gear portion of the pair of side gears has different outer diameters from each other.
The parallel shaft differential gear device according to any one of the above.