JPH09159009A - Differential gear mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve comfortability of a vehicle by providing a carrier supporting an external gear, which is a half of an internal gear in number, freely rotationally and a rotational body supported in a housing freely rotationally while matching its axis line with the rotation axis line of the hous ing and transmitting the rotation of the external gear to the rotational body. SOLUTION: When a housing 2 is rotationally driven, the whole of a device is integrally rotated if equal loads are applied, and output shafts 3A, 3B are rotated at the equal rotational speed. On the other hand, if different loads are applied, the output shaft 3A (3B) whose load is larger is rotated in the direction reverse to the rotation direction, while the output shaft 3B (3A) whose load is smaller is relatively rotated in the same direction as the rotation direction. As the number of teeth of an external gear 7 is set to be a half of that of an internal gear 4, the respective output gears 3A, 3B are rotated in the opposed directions relatively at the equal rotational speed. In the used gear, only two gears, which mean the internal gear 4 and the external gear 7, are used, and gearing is carried out in only a single position, so that rattling due to a backlash between gears can be reduced.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a differential gear device suitable for use in a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a differential gear device for a vehicle, there is a differential gear device using a pair of large bevel gears and a small bevel gear that meshes with each large bevel gear. In addition, recently, a differential gear device including a pair of side gears having torsion teeth and at least a pair of planetary gears that mesh with each side gear and mesh with each other has been used. There is an orthogonal axis type in which the axes of the and planetary gears are orthogonal to each other, and a parallel axis type in which the axes are parallel to each other (JP-A-49-50625, US Pat. No. 5,169).
370, etc.).

By the way, it is desirable for a differential gear unit used in a vehicle to have a small number of meshing points of gears. Backlash is a kind of backlash when gears mesh with each other. Therefore, if there are many meshing points, there will be more backlash,
This is because the riding comfort of the vehicle deteriorates.

[0004]

However, there are at least two meshing points in the differential gear device using the bevel gear, and there are at least three meshing points in the orthogonal shaft and parallel shaft type differential gear devices. In this way, since there are multiple meshing points in the conventional differential gear device,
When used in a vehicle, there is a problem that the riding comfort is deteriorated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the invention according to claim 1 provides a housing which is rotationally driven, and an axis line of the housing and a rotation axis line of the housing. An internal gear, which is provided so as to match and is not rotatable, an external gear that meshes with the internal gear, and is rotatably supported by the housing with its axis aligned with the rotation axis of the housing, and the external gear is rotatably supported. A carrier, a rotating body rotatably supported in the housing with its axis aligned with the rotation axis of the housing, and a rotation transmitting mechanism that transmits the rotation of the external gear to the rotating body. There is. In this case, it is desirable that the number of teeth of the external gear is half the number of teeth of the internal gear.
The internal gear and the external gear are preferably helical gears having helical teeth. It is desirable to use an Oldham shaft coupling as the rotation transmission mechanism.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. First, FIGS.
1 is described, the differential gear device 1 of this embodiment includes a housing 2 that is driven to rotate about an axis L. The housing 2 is composed of a cylindrical tubular portion 2A having a bottom portion 21 and a lid portion 2B that closes the opening of the tubular portion 2A, and these are integrally fixed by bolts (not shown). . A bearing hole 22 penetrating the bottom portion 21 of the cylindrical portion 2A and the central portion of the lid portion 2B is formed. Each bearing hole 2
The output shafts 3A and 3B are rotatably supported at 2, respectively.

The internal gear 4 is fitted in the tubular portion 2A of the housing 2 in a state of being in contact with the bottom surface of the tubular portion 2A. A key portion 41 is formed on the outer peripheral surface of the internal gear 4, and the internal gear 4 is integrated with the housing 2 by fitting the key portion 41 into the key groove 23 formed on the inner peripheral surface of the tubular portion 2A. It is designed to rotate. Of course, the internal gear 4 may be fixed to the housing 2 with a bolt or the like. Further, the internal gear 4 may be formed integrally with the housing 2.

A support hole 24 having a diameter slightly smaller than the inner diameter of the internal gear 4 is formed in the central portion of the bottom surface of the cylindrical portion 2A. An outer end of the carrier 5 is fitted and supported in the support hole 24 so as to be rotatable and axially movable. The carrier 5 may be fitted in the support hole 24 so as not to move in the axial direction. In this case, the carrier 5 is non-rotatably and axially movably connected to the output shaft 3A by spline coupling or the like, but may be formed integrally with the output shaft 3A. In such a case, it is desirable to provide the output shaft 3A with respect to the housing 2 so as to be movable in the axial direction so that the carrier 5 can be moved in the axial direction.

At the center of the inner end surface of the lid 2B,
The support hole 25 is formed. The support hole 25 has the same inner diameter as the support hole 24, but may have a different inner diameter. An outer end of the rotating body 6 is fitted into and supported by the support hole 25 so as to be rotatable and axially movable. The rotating body 6 may be fitted in the support hole 25 so as not to move in the axial direction. Further, in this case, the rotating body 6 is connected to the output shaft 3B in a non-rotatable and axially movable manner by spline coupling or the like, but may be formed integrally with the output shaft 3B. In such a case, it is desirable that the output shaft 3B be provided so as to be movable in the axial direction with respect to the housing 2 so that the rotating body 6 can be moved in the axial direction.

An external gear 7 meshes with the internal gear 4. Most of the external gear 7 (in this embodiment, a portion of about 3/4 of the entire circumference) except the meshing portion with the internal gear 4 is formed on the outer peripheral surface of the carrier 5 to be approximately 3 /.
It is rotatably fitted and supported in a four-circle support recess 51. Therefore, the external gear 7 can rotate and
It is possible to revolve around the internal gear 4, that is, around the axis L. Of course, when the external gear 7 revolves, the carrier 5
Also rotates with the external gear 7. Further, although the external gear 7 is supported by the support recess 51 of the carrier 5 so as to be movable in the axial direction, it may be supported immovably.

The number of teeth of the external gear 7 can be set to any number within a range in which the external gear 7 can be meshed with the internal gear 4 and rotated, but in this differential gear device 1, one output shaft 3A is a housing. It is set to half of the number of teeth of the internal gear 4 so that when it relatively rotates in one direction with respect to 2, the other output shaft 3B rotates in the opposite direction with respect to the housing 2 by the relative rotation. In addition, the external gear 7 and the internal gear 4
Is formed as a helical gear with helical teeth.
Therefore, the thrust force generated by the meshing with the internal gear 4 acts on the external gear 7. In this case, the acting direction of the thrust force differs depending on the twisting direction of the internal gear 4 and the external gear 7 or the rotational driving direction of the housing 2. The internal gear 4 and the external gear 7 may be spur gears.

Between the external gear 7 and the rotating body 6,
An Oldham coupling (rotary coupling mechanism) 8 is provided. That is, slide grooves 81, 82 having a quadrangular cross section are formed on the end surface of the external gear 7 on the side of the lid body 2B and the end surface on the side of the bottom portion 21 of the rotary body 6 so as to cross the respective central portions. A disc-shaped link 83 is arranged between the external gear 7 and the rotating body 6. Protrusions 84 and 85 are formed on both end faces of the link 83 so as to cross the respective central portions. The ridges 84 and 85 are arranged so as to be orthogonal to each other, and are slidably fitted in the slide grooves 81 and 82, respectively.

Next, the operation of the differential gear device 1 having the above structure will be described. Now, it is assumed that the housing 2 is rotationally driven. At this time, when the loads acting on the output shafts 3A and 3B are the same, the entire differential gear device 1 integrally rotates. Therefore, the output shafts 3A and 3B rotate at the same rotation speed. On the other hand, when the loads acting on the output shafts 3A and 3B are different, the output shaft 3A (3B) with the larger load rotates relative to the housing 2 in the opposite direction to the rotation direction of the output shaft 3A, and the load with the smaller load. The output shaft 3B (3A) rotates relative to the housing 2 in the same direction as the rotation direction. Particularly, in this differential gear device 1, the number of teeth of the external gear 7 is set to be half the number of teeth of the internal gear 4, so that the output shafts 3A and 3B have the same rotational speed with respect to the housing 2. Rotate relative to each other.

Here, in the differential gear device 1,
Only two gears, the internal gear 4 and the external gear 7, are used and only one meshing point is used. Therefore, the backlash due to the backlash between the gears can be reduced to half or less as compared with the conventional differential gear device. Therefore, when this differential gear device 1 is used in a vehicle,
Riding comfort can be improved. The ridges 84,
85 and the slide grooves 81, 82 are slidably fitted together, but these fittings are different from the meshing of the gears and require only the minimum clearance required to enable sliding. ,
The gap is significantly smaller than the backlash. Therefore, the clearance rarely affects the riding comfort.

Further, due to the meshing of the internal gear 4 and the external gear 7, a radial force acting in the radial direction acts on the external gear 7.
This radial force causes the outer peripheral surface of the external gear 7 to move to the carrier 5
While being pressed into contact with the inner surface of the support recess 51 of
The outer peripheral surface of the carrier 5 is pressed into contact with the support hole 22. Therefore, at the time of differential rotation, torque is generated between the external gear 7 and the carrier 5 to prevent the rotation of the external gear 7, and the carrier 5 is interposed between the carrier 5 and the housing 2.
Torque is generated to prevent the rotation of the. And
Output shaft 3A, 3B from housing 2 by the amount of the torque
There is a difference in the magnitude of the torque transmitted to the. That is, in this differential gear device 1, a so-called torque bias ratio is obtained.

Particularly, in this differential gear device 1, since the internal gear 4 and the external gear 7 have helical teeth, a larger torque bias ratio can be obtained. That is, since the internal gear 4 and the external gear 7 have torsion teeth, the meshing of them causes a thrust force in the axial direction to act on the external gear 7. In this case, if the direction of the thrust force acting on the external gear 7 is the right side in FIG. 1, the external gear 7 is pressed against the end surface of the support recess 51 of the carrier 5 by the thrust force, and the carrier 5 moves in the axial direction. Since it is movable, the end surface of the carrier 5 is pressed against the housing 2. As a result, a friction torque that tries to prevent the rotation of the carrier 5 is generated between them. If the direction of the thrust force acting on the external gear 7 is left in FIG. 1, the end faces of the external gear 7 and the link 8 and the end faces of the link 8 and the rotating body 6 are pressed into contact with each other. At the same time, the end surface of the rotating body 6 is pressed into contact with the housing 2. As a result, a frictional resistance force that tries to prevent their relative movement acts between the external gear 7 and the link 8 and between the link 8 and the rotating body 6, so that the rotating body 6 and the housing 2 are prevented from moving. In the meantime, a friction torque that tries to prevent the rotation of the rotating body 6 is generated. As described above, when the internal gear 4 and the external gear 7 are helical gears, friction torque or friction resistance is generated, and thus a larger torque bias ratio can be obtained.

In the above differential gear device 1,
Although the external gear 7 is supported in the support recess 51 of the carrier 5, a hole is formed in the center of the external gear 7, while the carrier 5
The external gear 7 may be rotatably supported by providing a shaft on the shaft and fitting the shaft into the hole of the external gear 7. However, in this case, the frictional resistance acting between the outer peripheral surface of the external gear 7 and the inner surface of the supporting recess 51 cannot be obtained, and the frictional resistance acting between the shaft and the hole is very small. . Therefore, the external gear 7 and the beating gear 4
Is required to be a helical gear.

Next, another embodiment of the present invention shown in FIG. 4 will be described. FIG. 4 is a frame diagram showing a differential gear device 1'according to the present invention. In 1 ', a universal joint 9 is used instead of the Oldham's joint 8. The other structure is the same as that of the differential gear device 1, and therefore the description thereof is omitted. Since the universal joint 9 cannot transmit the thrust force acting from the right side to the left side in FIG. 4, when the internal gear 4 and the external gear 7 are helical gears, the external gear 7 is moved to the right direction in FIG. It is preferable to determine the twisting direction so that the thrust force that points toward is applied.

[0019]

As described above, according to the first aspect of the present invention, the number of meshing points of the gear can be only one, so that the riding comfort can be improved when used in a vehicle. it can. Further, the torque distributed to the pair of output shafts can be made different in magnitude. According to the invention of claim 2, the relative rotation speeds of the pair of output shafts with respect to the housing can be made equal. According to the invention of claim 3, the torque bias ratio can be increased. According to the invention of claim 4, the same effects as those of the invention of claims 1 to 3 can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an internal gear, an external gear, an Oldham coupling, and a rotating body of the embodiment shown in FIG.

FIG. 3 is an exploded perspective view of the component shown in FIG.

FIG. 4 is a skeleton view showing another embodiment of the present invention.

[Explanation of symbols]

 L housing rotation axis 1 differential gear unit 1'differential gear unit 2 housing 4 internal gear 5 carrier 6 rotor 7 external gear 8 Oldham coupling (rotation transmission mechanism) 9 universal joint (rotation transmission mechanism)

Claims (4)

[Claims] 1. A housing which is rotationally driven, an internal gear which is fixed to the housing such that the axis of the housing coincides with the axis of rotation of the housing and which cannot rotate, an external gear which meshes with the internal gear, and an axis of the housing. A carrier rotatably supported in alignment with the rotation axis of the housing and rotatably supporting the external gear; and a rotating body rotatably supported in the housing with the axis aligned with the rotation axis of the housing. A rotation transmission mechanism for transmitting rotation of the external gear to a rotating body, the differential gear device. 2. The differential gear device according to claim 1, wherein the external gear has half the number of teeth of the internal gear. 3. The differential gear device according to claim 1, wherein the internal gear and the external gear have torsion teeth. 4. The differential gear unit according to claim 1, wherein the rotation transmission mechanism is an Oldham shaft joint.