JP2002310181A - Universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a transmitted torque capacity by enlarging the diameter of an axis of a cross-shaped spider while keeping a yoke member compact. SOLUTION: In both outer circumferential parts of a first axis 12 and a second axis 14 of a cross-shaped spider 10, notch parts 16a, 16b, 18a and 18b are provided at eight positions of two each in the both directions perpendicular to a range θ with small involvement with torque transmission, that is, a reference place S including both axis centers of the first axis 12 and the second axis 14. As the positions of these notch parts 16a, 16b, 18a, and 18b accord with a position of interference when the cross-shaped spider 10 is assembled to the yoke member, and the interference with the yoke member is reduced, and strength and the transmitted torque capacity can be increased by enlarging the diameters of the axis parts 12 and 14 of the cross-shaped spider 10 while keeping the size of the yoke member to a conventional size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint and, more particularly, to a technique for increasing the diameter of a shaft of a cross-shaped spider and maintaining a large yoke member, thereby increasing a transmission torque capacity.

[0002]

2. Description of the Related Art A universal joint for connecting a pair of yoke members in a tiltable manner with a cross-shaped spider and transmitting torque between the pair of yoke members via the cross-shaped spider is, for example, for connecting a propeller shaft of a vehicle. It is used for various power transmission parts such as parts. FIG. 9 shows an example of such a universal joint. The universal joint 100 includes a first yoke member 102 and a second yoke member 102.
A yoke member 104 and a cross-shaped spider 106 are mainly formed. A pair of arms 108 are provided on the yoke members 102 and 104 so as to be parallel to each other.
10 are provided. Also, the cross-shaped spider 106
Has a cross shape in which a pair of a first shaft portion 112 and a second shaft portion 114 intersect at right angles at a central portion, and both ends of the shaft portions 112 and 114 are respectively inserted into the connection holes 110. While being inserted, it is rotatably supported around an axis via a bottomed cylindrical cup 118. The cup 118 functions as a bearing member,
It has a built-in needle bearing 116 and is integrally fixed to the arm 108 by a snap ring or caulking (not shown), while an oil seal 120 is provided between the opening of the cup 118 and the shafts 112 and 114.
Is arranged. FIG. 9A is an exploded perspective view before assembly.
FIG. 4B is a cross-sectional view of a connection portion between the first yoke member 102 and the first shaft portion 112.

In such a universal joint 100, for example, first, as shown in FIGS. 10A to 10J, a first shaft portion 112 of a cross-shaped spider 106 is assembled to a first yoke member 102, and thereafter, In a similar manner, the second shaft portion 114 is usually assembled to the second yoke member 104. A first yoke member 102,
The assembling order for the second yoke member 104 may be reversed. Also, since the first shaft portion 112 and the second shaft portion 114 usually have the same shape, the first shaft portion 112 is assembled to the second yoke member 104 and the second shaft portion 114 is connected to the first yoke member 102. May be assembled.

Here, in such a universal joint 100, in order to increase the transmission torque capacity, the shaft 1 of the cross-shaped spider 106 is required to increase the strength.
Although it is necessary to increase the diameter of the shafts 12 and 114, if the diameter of the shafts 112 and 114 is increased, (b) of FIG.
Since the three parts A to C shown by broken lines interfere with the arm 108 and become impossible to assemble, the dimensions of the yoke members 102 and 104 also need to be increased, so that a weight increase and a large arrangement space are required. There was a problem.

On the other hand, for example, Japanese Unexamined Utility Model Publication No.
In the official gazette, the shaft of the cross-shaped spider is made separable,
A technique for increasing the shaft diameter while keeping the yoke member compact is described.

[0006]

However, if the shaft of the cruciform spider is made separable in this manner, the strength and durability of the joint may be impaired, so that the cruciform spider itself is considerably enlarged. In addition to the necessity, the manufacturing cost is increased because the structure is complicated and the number of parts is increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cross-shaped spider while keeping the yoke member compact without making the shaft of the cross-shaped spider separable. Is to increase the diameter of the shaft portion to increase the transmission torque capacity.

[0008]

According to a first aspect of the present invention, a pair of yoke members are tiltably connected by a cross-shaped spider, and the pair of yoke members are connected via the cross-shaped spider. In a universal joint for transmitting torque between the cross-shaped spiders, a notched portion is provided in a portion of the shaft outer portion of the cross-shaped spider that is less involved in torque transmission.

According to a second aspect of the present invention, in the universal joint according to the first aspect of the present invention, the two ends of each of a pair of the first shaft portion and the second shaft portion intersecting at right angles constituting the cross-shaped spider are provided. The underfill portions are provided at a total of eight locations, two locations each located in both directions perpendicular to the reference plane including both the axis of the first shaft portion and the second shaft portion. It is characterized by.

[0010]

In such a universal joint, a portion of the outer periphery of the tip of the shaft of the cruciform spider which is less involved in torque transmission is provided with a notched portion, as shown in FIG. Interference between the yoke member and the cross-shaped spider when assembling to the yoke member is reduced. That is, around the respective axes of the pair of first shaft portions and the second shaft portions that intersect at right angles that constitute the cross-shaped spider, the portions that greatly contribute to torque transmission are the first shaft portions and the second shaft portions. Since the portion substantially coincides with the reference plane including both axes of the two-axis portions, the interference portions A and B shown in FIG. Since the underfill portion is provided, interference with the yoke member at the time of assembly is reduced.

Thus, while maintaining the size of the yoke member at about the same size as the conventional one, the diameter of the shaft portion of the cross-shaped spider can be increased to increase the strength and the transmission torque capacity. In this case, the underfilled portion is provided in a portion where the contribution to the torque transmission is small, so that there is almost no effect on the strength and the transmitted torque capacity, and the strength and the transmitted torque capacity are improved as the diameter of the shaft portion is increased. Further, if the diameter of the shaft of the cross-shaped spider is the same, the assembling work on the yoke member becomes easy, and the interference of the portion C shown in FIG. 10 (b) is reduced. The degree of freedom in size and shape design is increased.

In the second invention, a pair of the first shaft portion and the second shaft portion are provided.
Since the underfill portions are provided at both ends of the shaft portion, the size of each underfill portion can be reduced as compared with the case where the underfill portion is provided only at one end in the axial direction, and the strength and transmission torque can be reduced. The effect on the capacity is further reduced, and the effect on bearings such as a needle bearing that rotatably supports these shafts is also reduced. That is, if the underfill reaches the bearing portion, stress concentration occurs in the bearing at the boundary between the underfill, and the durability of the bearing may be impaired.

On the other hand, interference portions A and B shown in FIG.
As can be seen from FIG. 3, the outer periphery of the tip of each shaft (the outer periphery at both ends in the axial direction) interferes with the yoke member at only one location around the axis, so that only the underfill is provided at that location. Good, but in that case, it is necessary to pay attention to the orientation when the cross-shaped spider is assembled to the yoke member. On the other hand, in the second invention, the underfill portions are respectively provided at two positions located in both directions perpendicular to the reference plane, so that the assembling work can be performed without worrying about the assembling direction, The assembling workability is not impaired due to the underfill.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 9, for example, a universal joint according to the present invention has a pair of first shaft portions and a second shaft portion of a cross-shaped spider. And is configured to be rotatably supported by a bearing member about an axis. The bearing member desirably incorporates a bearing such as a needle bearing, and a cylindrical cup having a closed bottom and a closed bottom is widely used. It can also be used.

The present invention is suitably applied to a case where the cross-shaped spider is integrally formed by forging or the like, but is also applied to a cross-shaped spider in which a separately formed shaft portion is integrally fixed. Can be done. In short, the effect of the present invention can be obtained when the shaft is inserted into the connecting hole of the yoke member and assembled while the cross-shaped spider is inclined as shown in FIG.

As a mode of transmitting the torque between the pair of yoke members via the cross-shaped spider, the torque transmission direction is reversed at the time of forward movement, reverse movement, etc. as in the case of use in a vehicle power transmission unit. However, the torque may always be transmitted from one yoke member to the other yoke member.

The underfill portion provided at the tip of the shaft portion can be provided later by chamfering by cutting or polishing, but if provided at the forging stage, it can be easily performed without increasing the number of processes. Can be formed. However, forging is not an essential requirement.

The shape of the underfill portion may be a flat surface, but is appropriately set such as a convex arc shape or a convex spherical shape. Although a concave shape can be used, it is not preferable in terms of strength. When the underfill reaches the bearing portion, it is desirable to provide a smooth roundness at the boundary of the underfill to prevent a reduction in the life of the bearing due to stress concentration.

In the second invention, a pair of the first shaft portion and the second shaft portion are provided.
There are a total of eight underfill portions at each of the two end portions of the shaft portion. However, the interference with the yoke member during assembly is only one portion around the axis, so the first shaft portion has a reference plane. In addition to the above, two underfill portions are provided at one location on one side and two underfill portions are provided at two locations on the other side of the second shaft portion with the reference plane interposed therebetween. May be provided. Further, the interference can be reduced and the diameter can be increased simply by providing the underfill portion only at one end in the axial direction.

It is desirable that the first shaft portion and the second shaft portion have the same diameter and the same shape from various viewpoints such as workability in assembling and vibration characteristics. It is also possible for the second shaft portion to have a different diameter. In addition, in the case where the size of one yoke member can be increased in terms of an installation space or the like, it is only necessary to provide the underfill portion on either one of the first shaft portion and the second shaft portion.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. The cross-shaped spider 10 of FIG.
(A) is a perspective view, and (b) to (d) are views viewed from arrows B and C in (a), respectively. , D arrow view. The cross-shaped spider 10 has a cross shape in which a pair of first shaft portions 12 and second shaft portions 14 intersect at right angles at a central portion, and the first shaft portions 12 and second shaft portions thereof are arranged. At both ends (tips) of each of the 14
Two flat portions 16a, 16b, 18a, and 18b are provided at two positions located in both directions perpendicular to the reference plane S including both axes of the first shaft portion 12 and the second shaft portion 14, respectively. ing. The first shaft portion 12 and the second shaft portion 14 have the same diameter and the same shape, and each of the thinned portions 16a, 16b, 1
8a and 18b also have the same shape.

The angle range θ in which the notched portions 16a, 16b, 18a and 18b are provided around the respective axes of the first shaft portion 12 and the second shaft portion 14 is a portion where the contribution to torque transmission is small, and the yoke member It is determined in consideration of use conditions such as the inclination angle (joint angle) of 102 and 104. FIG. 2 shows the result of examining the surface pressure distribution of abcd around the axis of one shaft part by arranging the universal joint 100 using the conventional cruciform spider 106 at the connection part of the propeller shaft of the vehicle. The portions b and d, which substantially coincide with the plane S, have a high surface pressure and are largely involved in torque transmission. Part b is a part that transmits torque during forward traveling, and part d is a part that transmits torque during backward traveling, and the magnitude of the surface pressure changes depending on the transmitted torque. The angle range θ is defined in the vicinity of the portions a and c where the contribution to the torque transmission is small, that is, in a region in a direction perpendicular to the reference plane S. ) Increases as the inclination angle of the yoke members 102 and 104 increases, and the angle range θ accordingly increases.
Becomes smaller. Although FIG. 2 shows the result of examining one of the four shaft portions, the other shaft portions show the same tendency.

Then, the missing portions 16a, 16b, 18a,
18b is provided in the range of the above angle range θ, and FIG.
, (D) are determined in consideration of assemblability, required strength, durability of the needle bearing 116, and the like.

FIG. 3 is a view showing a manufacturing process of the cross-shaped spider 10. The forging process for forming the whole shape by forging, the cutting process for cutting the outer peripheral surfaces and the tip surfaces of the shaft portions 12 and 14, the baking process, and the like. It is manufactured integrally through a heat treatment step of performing a filling treatment and the like and a polishing step of finish polishing the outer peripheral surfaces of the shaft portions 12 and 14. In this case, the underfilled portions 16a, 16
For example, b, 18a, and 18b are provided in a forging process as shown in FIG. 4, and can be easily formed without increasing the number of processes as compared with a case in which they are provided by cutting or polishing. FIG. 4 is a cross-sectional view showing the shape of one end of the first shaft portion 12 after the forging process. The outer peripheral surface and the distal end surface outside the dotted line are portions removed by the cutting process. In addition, the missing portion 16
a, 16b, 18a, and 18b may be as-forged, but may be subjected to finish polishing or the like as necessary.

Further, as shown in FIG.
When the a and 16b reach the bearing portion of the needle bearing 116, as shown in FIG.
It is desirable that a smooth roundness is provided at the boundary 20 of the shaft 16b so as to be smoothly connected to the outer peripheral surface of the shaft portion 12 to prevent the life of the needle bearing 116 from being shortened due to stress concentration. The same applies to the underfill portions 18a and 18b of the second shaft portion 14.

As described above, the cross-shaped spider 1 of the present embodiment
0 is the outer peripheral portion of the distal end of the shaft portions 12 and 14, and the thinned portions 16 a and 16
b, 18a, and 18b are provided,
As shown in (1), the interference between the yoke members 102, 104 and the cross-shaped spider 10 when assembled to the yoke members 102, 104 is reduced. In other words, the portion that greatly contributes to the torque transmission around the axis of the pair of first shaft portion 12 and the second shaft portion 14 constituting the cross-shaped spider 10 is a portion that substantially matches the reference plane S. In the direction perpendicular to the reference plane S, specifically, in the interference portions A and B shown in FIG.
8b are provided, and the yoke members 102, 10
4 is reduced.

Thus, the cross-shaped spider 1 is maintained while the yoke members 102 and 104 are maintained at the same size as the conventional one.
The diameters of the 0 shaft portions 12 and 14 can be increased to increase the strength and the transmission torque capacity. For example, the conventional yoke members 102 and 104 are diverted as they are, and the cross-shaped spider 10 is used.
By simply changing the needle bearing 116, the strength and capacity of the universal joint 100 can be improved. In that case, the missing portions 16a, 16
Since b, 18a, and 18b are provided in portions where the contribution to the torque transmission is small, there is almost no effect on the strength and the transmission torque capacity, and the strength and the transmission torque capacity are improved as the diameter of the shaft portions 12 and 14 increases.

The shafts 12, 1 of the cross-shaped spider 10
4 have the same diameter, the yoke members 102, 104
10 is easy to assemble, and FIG.
(1), the degree of freedom in designing the size and shape of the oil seal 120 is increased.

In this embodiment, the thinned portions 16a, 16b, 18a,
18b, the individual thinned portions 16a, 16a are compared with the case where the thinned portions are provided only at one end in the axial direction.
The size of b, 18a, 18b can be reduced, the influence on the strength and the transmission torque capacity is further reduced, and the influence on the needle bearing 116 that rotatably supports the shafts 12, 14 is also reduced. That is,
When the underfilled portions 16a, 16b, 18a, and 18b reach the bearing portion of the needle bearing 116, the underfilled portion 1
At the boundary between 6a, 16b, 18a, and 18b, stress concentration occurs in the needle bearing 116, and its durability may be impaired. As shown in FIG. 5, a smooth roundness is provided at the boundary 20 between the underfill portions 16a, 16b, 18a, and 18b so as to smoothly connect to the outer peripheral surfaces of the shaft portions 12 and 14.
6 is more effectively prevented from being shortened.

In addition, the notched portions 16a, 16b, and 18 are provided at two positions located in both directions perpendicular to the reference plane S, respectively.
a, 18b, the assembling work can be performed without worrying about the assembling direction.
The assembly workability is not impaired due to 16b, 18a, 18b. That is, as is apparent from the interference portions A and B shown in FIG.
Since it interferes with one point around the axis, the first shaft part 1 can be, for example, like a cross-shaped spider 30 shown in FIG.
2 is provided with a total of two underfill portions 16a located on one side (upper side in the figure) with respect to the reference plane S.
May be provided only with a total of two underfill portions 18b located on the other side (lower side in the figure) with respect to the reference plane S. In this case, the cross-shaped spider 30 is attached to the yoke member 102.
When assembling, it is necessary to assemble in such a position that the underfilled portion 16a is on the yoke member 102 side, and the assembling work becomes troublesome. In this embodiment, the first shaft portion 12 and the second shaft portion 12
Since the shaft portions 14 have the same shape, the second shaft portion 14 may be assembled to the yoke member 102.
8b is the same in that it is assembled in a posture in which it is on the yoke member 102 side.

The cross-shaped spider 30 is provided with notched portions 16a, 18b at both ends of the first shaft portion 12 and the second shaft portion 14.
However, as in the cross-shaped spider 40 shown in FIG. 7, the underfill portions 16a and 18b may be provided only at one end in the axial direction. In that case, the yoke member 102,
In order to avoid the interference with the cross spider 104 and enable the assembling, the underfilled portions 16a, 18
It is necessary to increase the dimension of b.

The cross-shaped spider 50 shown in FIG.
Compared to the cross-shaped spider 40 shown in FIG.
2, 14 symmetrical positions with respect to the axis, that is, the reference plane S
Two portions located in both directions perpendicular to
a, 16b, 18a, and 18b.

Although the embodiments of the present invention have been described in detail with reference to the drawings, these embodiments are merely one embodiment, and the present invention is based on the knowledge of those skilled in the art. Can be implemented.

[Brief description of the drawings]

FIG. 1 is a view showing a cross-shaped spider of a universal joint according to one embodiment of the present invention, wherein (a) is a perspective view, and (b) to (b).
(d) is a view taken in the direction of the arrow B, C, and D in FIG.

FIGS. 2A and 2B are diagrams illustrating an example of a surface pressure distribution in a circumferential direction of a shaft portion of a cross-shaped spider, wherein FIG.
FIG. 4B is a diagram showing a surface pressure distribution at circumferential positions a to d.

FIG. 3 is a diagram illustrating a manufacturing process of the cross-shaped spider of FIG. 1;

FIG. 4 is a diagram showing a cross-sectional shape of a shaft portion after forging when providing a notched portion in a forging step.

FIG. 5 is a diagram showing an aspect in which a rounded portion is provided at the boundary of the underfill portion when the underfill portion interferes with the needle bearing;
(a) is a perspective view showing a shaft, and (b) is a sectional view of the shaft.

FIG. 6 is a perspective view of a cross-shaped spider according to another embodiment of the present invention, corresponding to FIG. 1 (a).

FIG. 7 is a perspective view of a cruciform spider according to still another embodiment of the present invention, corresponding to FIG. 1 (a).

FIG. 8 is a perspective view of a cross-shaped spider according to still another embodiment of the present invention, and is a view corresponding to FIG.

9A and 9B are views illustrating a conventional universal joint, in which FIG. 9A is an exploded perspective view, and FIG. 9B is a cross-sectional view of a connecting portion between a shaft of a cross-shaped spider and a yoke member.

10 is a process diagram illustrating a procedure when assembling the cruciform spider of the universal joint of FIG. 9 to a yoke member.

[Explanation of symbols]

10, 30, 40, 50: cross-shaped spider 12: first shaft 14: second shaft 16a, 16b, 18
a, 18b: underfill 102: first yoke member 104: second yoke member S: reference plane

Claims (2)

[Claims] 1. A universal joint in which a pair of yoke members are tiltably connected by a cross-shaped spider and torque is transmitted between the pair of yoke members via the cross-shaped spider, wherein a shaft portion of the cross-shaped spider is provided. A universal joint, characterized in that a notched portion is provided in a portion of the outer peripheral portion of the tip that is less involved in torque transmission. 2. A pair of first shaft portions and a second shaft portion that intersect at a right angle and that constitutes the cross-shaped spider, wherein both ends of the first shaft portion and the second shaft portion are provided. A universal joint, wherein the underfill portions are provided at a total of eight locations, two locations each located in both directions perpendicular to a reference plane including both axes.