JPH0771562A - Backlash reducing method in worm gear type differential gear device - Google Patents

Abstract

PURPOSE:To reduce the backlash in the entire differential gear device, and to enhance operational feeling by moving element gears forming pairs in such a way that they are detached from the tooth surfaces on the one side of side gears and are brought near to the tooth surfaces on the other side thereof, and by fixing the positions of the element gears after movement. CONSTITUTION:In a differentiaI gear device provided with a pair of side gears 2 (2A, 2B) and two pairs of element gears 4 (4A, 4B) and 5 (5A, 5B), when it is assembled, after the positions of the pair of element gears 5 (5A, 5B) have been fixed, the pair of element gears 4 (4A, 4B) are moved in the X direction or in the axial direction of the side gears 2 (2A, 2B). Thereby, the tooth surfaces (41A, 41B) of the respective gears 4 (4A, 4B) are brought near to the tooth surfaces (21A, 21B) of the respective gears 2 (2A, 2B), and the tooth surfaces (51A, 51B) of the gear 5 (5A, 5B) are brought near to the tooth surfaces (22A, 22B) of the respective gears 2 (2A, 2B) for fixing the entire positioning. Then, by fixing the positions of the gears 4 (4A, 4B), the tooth surfaces (41A, 41B; 51A, 51B) of the respective gears 4, 5 are maintained in the condition that they are brought into contact with the tooth surfaces (21A, 21B; 22A, 22B) of the 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 method for reducing play in a worm gear type differential gear device using a worm gear mechanism.

[0002]

2. Description of the Related Art Generally, a worm gear type differential gear device is constructed as shown in FIGS. That is, in these drawings, reference numeral 1 is a housing which is rotationally driven about an axis of rotation L by an engine (not shown), and on the axis of rotation L of the housing 1,
A pair of side gears 2A and 2B are rotatably supported. Axles 3A and 3B are connected to the side gears 2A and 2B, respectively, by spline fitting or the like. The wheels 3A and 3B are connected to left and right wheels (not shown), respectively.

In the housing 1, a plurality of pairs (three pairs in this example) of element gears 4A, 4B; 5A, 5B; 6A, each axis of which is oriented in a direction orthogonal to the axis L,
6B is rotatably supported via a shaft 7. The element gears 4A, 5A, 6A mesh with the side gear 2A, and the element gears 4B, 5B, 6B mesh with the side gear 2B. Each element gear 4A-6B
Spur gears (gear portions) 8 are formed on both end portions of each. Paired element gears 4A, 4B; 5A, 5
B; 6A and 6B spur gears 8 mesh with each other.

In the differential gear device having the above structure, when the loads acting on the left and right wheels are the same, when the housing 1 is rotationally driven, the entire differential gear device rotates integrally. Therefore, the left and right wheels rotate at a constant speed. on the other hand,
When the load acting on each wheel is different, the element gears 4A, 5A, 6A and 4B, 5B, 6B rotate in opposite directions to each other, whereby the rotation of the wheel having a large load is delayed, and the load is correspondingly increased. The small wheels will rotate faster.

[0005]

By the way, in the differential gear device, backlash is required for smooth engagement between the side gears 2A, 2B and the element gears 4A-6B. However, it is desirable to minimize this backlash.

However, the housing 1 and the sides 2A, 2
Since B and the element gears 4A to 6B have manufacturing errors and assembly errors, backlash tends to increase. If the backlash is large, when the contact tooth flanks of the side gears 2A and 2B and the element gears 4A to 6B change, such as when the engine brake is applied from normal running, the contact tooth flanks are immediately converted. However, the two gears are relatively rotated by the amount of the backlash (the relative rotation amount between the gears is referred to as rattling in the present invention), which deteriorates the driving feeling. Further, the rotational speed difference between the two gears increases until the contact tooth surface changes from one tooth surface to the other tooth surface, and the tooth surfaces of the gears collide with each other with a large speed difference. For this reason, there is a problem that noise is increased.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is rotatably supported by a housing which is driven to rotate and whose housing has an axis aligned with the axis of rotation of the housing. A pair of side gears, and a plurality of pairs of element gears that are rotatably supported by the housing in a direction orthogonal to the rotation axis of the housing and mesh with the pair of side gears. In a worm gear type differential gear device in which gear parts meshing with each other are provided, part of the element gears of the plurality of pairs are fixed in position, and the other part of the element gears of each pair is fixed. Identical to each other so that one tooth surface of the tooth approaches the tooth surface of the opposing side gear and separates from the other tooth surface of the side gear. Is moved to the direction, is characterized in that position-fixing elements gear pairs were then moved.

A specific method for moving one tooth surface of the element gear toward the tooth surface of the opposite side gear and moving it away from the other tooth surface is to move the element gear in the axial direction thereof. There are methods such as moving, moving in the axial direction of the side gear, moving in the combined direction thereof, moving in the circumferential direction of the element gear, and the like.

[0009]

Now, as shown in FIG. 2, the differential gear device has a pair of side gears 2A, 2B and two pairs of element gears 4A,
4B; 5A and 5B. In this differential gear device, when the pair of element gears 5A and 5B are fixed in position and the pair of element gears 4A and 4B are moved in the axial direction X direction of the side gears 2A and 2B, the tooth surface 41A of the element gears 4A and 4B is obtained. , 41B approach the tooth flanks 21A, 21B of the side gears 2A, 2B, and the tooth flanks 51A, 51B of the element gears 5A, 5B move to the side gears 2.
The tooth surfaces 22A and 22B of A and 2B come close to each other.

To explain this point in more detail, the pair of element gears 4A and 4B move in the X direction, and the tooth surfaces 41A and 41B face counterclockwise in FIG.
Separates from one tooth surface 22A, 22B of the side gears 2A, 2B and approaches the other tooth surface 21A, 21B. Then, after the tooth surfaces 41A, 41B contact the tooth surfaces 21A, 21B, when the pair of elements 4A, 4B are further moved, the pair of element gears 4A, 4B will move to the side gear 2
A and 2B try to rotate them in the same clockwise direction. However, the side gears 4A and 4B cannot rotate in the same direction because the spur gears 8 and 8 mesh with each other. Therefore, the side gears 4A, 4B
Will be rotated. The side gear 2A,
Since 2B has the same twisting direction, it rotates in the same direction.

When the pair of side gears 2A and 2B rotate in the same direction, the rotation causes the side gears 2A and 2B to rotate.
The tooth flanks 22A and 22B of 2B approach the tooth flanks 51A and 51B of the other pair of element gears 5A and 5B, and finally contact each other. And the other pair of elements 5A and 5B
To rotate in the same clockwise direction or to move in the same direction as the side gears 4A and 4B (arrow X). However, the element gears 5A and 5B cannot rotate in the same direction because the spur gears 8 and 8 mesh with each other. Further, since the element gears 5A and 5B are fixed in position, they cannot move in the arrow X direction. Therefore, the tooth surfaces 51A and 51B and the tooth surface 22
After A and 22B contact, element gears 4A and 4B
Cannot be moved in the X direction, and the position is fixed in that state.

When the element gears 4A and 4B are moved in the X direction in this way, the element gears 4A and 4B are moved.
The tooth surfaces 41A, 41B of 4 contact the side gears 21A, 21B, and the tooth surfaces 22A, 22B of the side gears 2A, 2B contact the tooth surfaces 51A, 51B of the element gears 5A, 5B, whereby the whole position is fixed. Therefore, if the position of the element gears 4A and 4B is fixed in this state,
The tooth surfaces 41A, 41B of the element gears 4A, 4B are in contact with the tooth surfaces 21A, 21B of the side gears 2A, 2B, and the tooth surfaces 51A, 51B of the element gears 5A, 5B are in contact with the tooth surfaces 22A, 22B of the side gears 2A, 2B. It will be kept in contact.

When the housing (not shown) of the differential gear unit is rotated in the direction of the arrow about the axis L in the above state, the tooth surfaces 4 of the pair of element gears 4A and 4B are rotated.
1A and 41B are tooth surfaces 21A and 21B of the sides 2A and 2B.
, The side gears 2A, 2B rotate in the same direction at the same time as the housing rotates. At this time,
The other pair of element gears 5A, 5B has a tooth surface 5
2A, 52B and tooth surfaces 21A, 2 of the side gears 2A, 2B
Since there is a gap between the side gears 2A and 2B,
Never rotate.

When the housing is rotated in the direction opposite to the arrow direction, the tooth flanks 5 of the pair of element gears 5A and 5B are formed.
1A and 51B are tooth surfaces 22A and 2 of the side gears 2A and 2B.
Since it is in contact with 2B, the side gears 2A and 2B rotate in the same direction at the same time as the housing rotates in the opposite direction.
At this time, the element gears 4A and 4B have their tooth surfaces 42
A and 42B are tooth surfaces 22A and 22 of the side gears 2A and 2B.
Since it is separated from B, the side gears 2A and 2B are not rotated.

Further, in the case where the housing is rotating in the direction of the arrow, the case where the housing is turned to the driven side due to the next moment engine braking applied to the driving side will be described. As described above, the sides 2A and 2B are rotationally driven by the element gears 4A and 4B. When the housing shifts to the driven side from this state, the braking force acting on the axle is transmitted from the tooth surfaces 22A, 22B of the side gears 2A, 2B to the element gears 5A, 5B. At this time, since the tooth surfaces 22A, 22B of the side gears 2A, 2B and the tooth surfaces 51A, 51B of the element gears 5A, 5B are constantly in contact with each other, rattling due to backlash does not occur and the housing rolls to the driven side. At the same time, the engine brake is applied. Therefore, it is possible to improve the driving feeling and prevent the generation of noise due to the collision of the tooth surfaces.

When the housing is rotating in the direction opposite to the direction of the arrow and the engine is braked, the element gears 5A and 5B are initially set to the side gears 2.
It goes without saying that the element gears 4A and 4B are rotationally driven by the side gears 2A and 2B after driving A and 2B and applying the engine brake.

Further, when the housing is rotating in the direction of the arrow, the loads acting on the left and right side gears 2A and 2B are different, and, for example, the side gear 2A rotates relative to the housing in the direction opposite to the rotating direction. In this case, the element gear 4A that is in contact with the tooth surface 21A is rotated clockwise. The clockwise rotation of the element gear 4A causes the element gear 4B to rotate counterclockwise, which causes the side gear 2B to rotate relatively to the housing in the same direction as the rotation direction. That is, the speed is increased. Conversely, when the side gear 2B relatively rotates in the opposite direction to the housing, the relative rotation amount is transmitted to the side gear 2A via the element gear 4B and the element gear 4A, and the side gear 2A is accelerated. At this time, the tooth flanks 51A, 51B of the element gears 5A, 5B are the tooth flanks 2 of the side gears 2A, 2B.
Since it is not in contact with 1A, 21B, side gears 2A,
It does not receive rotational force from 2B.

On the other hand, when the housing is rotating in the direction opposite to the arrow, the left and right side gears 2A, 2B
When the loads acting on the element gears 5A (5B) are different, the deceleration of one side gear 2A (2B) is reduced.
B) is transmitted to the element gear 5B (5A), and the other side gear 2B (2A) is accelerated. Of course, in this case, the element gears 4A and 4B do not receive the rotational force.

In the above case, the pair of element gears 4A and 4B are moved to bring the tooth surfaces of the element gears 4A to 5B into contact with the tooth surfaces of the side gears 2A and 2B. The same applies when the position of the pair of element gears 4A and 4B is fixed and the other pair of element gears 5A and 5B is moved. Further, the tooth surfaces 41A, 41B of the element gears 4A, 4B are brought into contact with the tooth surfaces 21A, 21B of the side gears 2A, 2B, and the tooth surfaces 51A, 51B of the element gears 5A, 5B are brought into contact with the tooth surfaces 22A, 22B of the side gears 2A, 2B. However, in actuality, a slight gap is provided between the tooth surfaces which are brought close to each other so that the side gears 2A and 2B and the element gears 4A to 5B can smoothly mesh and rotate. It is better to do so.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a differential gear device which is suitable for carrying out the method of the present invention. The difference from the above-mentioned conventional example in this differential gear device is that a pair of element gears 4A, 4B The point is that it is movable in the direction of the axis L as long as possible.

That is, the peripheral wall portion of the housing 1 is provided with a rectangular mounting hole 1a whose longitudinal direction is oriented in the same direction as the rotation axis L. A casing 9 having a quadrangular frame shape is mounted in the mounting hole 1a so as to be movable in the same direction as the rotation axis L. Rotation axis L of this casing 9
A pair of element gears 4A and 4B are rotatably supported on one end side and the other end side in the direction via a shaft 7 with their axes oriented in a direction orthogonal to the rotation axis L. Of course,
The element gears 4A and 4B mesh with the side gears 2A and 2B, respectively, and spur gears 8 formed at both ends of the element gears 4A and 8B mesh with each other.

At both ends of the long side of the casing 9,
Each screw hole 9a is formed. A bolt insertion hole 1b is formed in the peripheral wall portion of the housing 1 facing each screw hole 9a.
Are formed. This bolt insertion hole 1b is shown in FIG.
As shown in (B), it is formed as an elongated hole extending in the direction of the rotation axis L. Further, a bolt seat 1c is formed on the outer peripheral surface of the housing 1 where the bolt insertion hole 1b is opened. The casing 9 is fixed to the housing 1 by the bolt 10 that is inserted into the bolt insertion hole 1b and screwed into the screw hole 9a.

The other two pairs of element gears 5A, 5
Although B; 6A and 6B are not shown, they are rotatably supported while being fixed in position in the housing 1 in the same manner as shown in FIGS. 3 and 4.

In the differential gear device of the above construction, by moving the casing 9 in one direction of the rotation axis L of the housing 1, one tooth surface of the element gears 4A, 4B and one tooth of the side gears 2A, 2B are moved. Faces can be brought closer together and other tooth flanks can be separated. Also,
By moving the element gears 4A, 4B in the same direction, one of the tooth surfaces of the element gears 5A, 5B; 6A, 6B (the tooth surface facing the same rotation direction as the element gears 4A, 4B) and the side gears 2A, 2B. The other tooth flank can be brought closer.

As described above, the elements 4A ...
6B and the side gears 2A and 2B are preferably provided with a slight gap between the tooth surfaces which are brought close to each other so that they can mesh smoothly with each other. Such a gap can be obtained, for example, by moving the casing 9 in one direction until it becomes immovable and then moving it in the opposite direction by a predetermined distance.

The present invention is not limited to the above embodiments, but can be modified as appropriate without departing from the scope of the invention. For example, in the above-described embodiment, the pair of element gears 4A and 4B are provided in the casing 9 and are moved by the same distance at the same time, but as long as they are moved in the same direction, they are moved separately from each other and are different. You may make it move only a distance.

[0027]

As described above, according to the backlash reduction method for the worm gear type differential gear device of the present invention, the paired element gears are separated from one tooth surface of the side gear and approach the other tooth surface. As described above, since the position of the element gear that has been moved afterwards is fixed, it is possible to reduce play in the entire differential gear device, and thereby to improve the driving feeling. The effect that noise can be reduced can be obtained.

[Brief description of drawings]

1 shows an example of a differential gear device suitable for carrying out the method of the present invention, FIG. 1 (A) is a partially cutaway side view, and FIG. 1 (B) is shown in FIG. ) Partially omitted B arrow view.

FIG. 2 is a view for explaining the action of the present invention in the direction of reducing play.

FIG. 3 is a vertical sectional side view showing an example of a conventional differential gear device.

FIG. 4 is a sectional view taken along the line YY of FIG.

[Explanation of symbols]

 L Housing rotation axis 1 Housing 2A Side gear 2B Side gear 4A Element gear 4B Element gear 5A Element gear 5B Element gear 6A Element gear 6B Element gear 8 Spur gear (Gear part) 9 Casing 21A Tooth surface 21B Tooth surface 22A Tooth surface 22B Tooth surface 41A tooth surface 41B tooth surface 42A tooth surface 42B tooth surface 51A tooth surface 51B tooth surface 52A tooth surface 52B tooth surface

Claims (1)

[Claims] 1. A housing driven to rotate, a pair of side gears rotatably supported by the housing such that the axis of the housing coincides with the axis of rotation of the housing, and the axis of the housing extends in a direction orthogonal to the axis of rotation of the housing. In a worm gear type differential gear device, which is rotatably supported toward each other, includes a plurality of pairs of element gears that mesh with the pair of side gears, and the pair of element gears are provided with gear portions that mesh with each other. Positionally fixing a part of the pair of element gears of the plurality of pairs, one of the other part of the pair of element gears is closer to the tooth surface of the side gear where one tooth surface of each tooth is opposed to this.
A backlash reducing method for a worm gear type differential gear device, characterized in that the pair of element gears are moved in the same direction so as to be separated from the other tooth surface of the side gear, and then the pair of moved element gears are fixed in position.