JPS61153019A - Equi-speed joint - Google Patents

Abstract

PURPOSE:To achieve smooth rotation by forming at least one of a ball and a ball groove with reinforced plastic having lower resiliency and producing pressure contacting force through resilient deformation at the contacting section between the ball and the ball groove. CONSTITUTION:The yoke joint in equi-speed joint is formed by burrying a steel material as a core metal 3 into the reinforced plastic material. The ball groove 2 for containing the ball 1 is finished with minus tolerance against the curvature of ball 1 when molding. Consequently, when assembling, the ball 1 is inserted into the ball groove 2 then they are pressure contacted continuously through resilient deformation of the plastic material. As a result, the ball 1 can be contained tightly in the ball groove 2 to simplify adjusting of pre- pressurization thus to enable smooth transmission of rotation from input side yoke to the output side yoke even for high joint angle.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to applications where the joint angle (the angle formed by the input/output yoke) is high and play in the rotational direction is a problem, such as steering wheel joints for automobiles. Regarding constant velocity joints such as Weiss type.

[Conventional technology]

For example, it is known that a Weiss type constant velocity joint generally has good uniform velocity and rotates smoothly.

For example, as shown in FIG. 4aSb, the Weiss type constant velocity joint consists of an input/output yoke 11.12 and a ball 13.14. The yoke 11.12 has axially extending joints, each joint being provided with ball grooves 15, 16, 17, 18 on the side surfaces thereof which cooperate with each other to hold the balls. The cross section of the groove is an arc of radius r, and the ball 19 is in contact with the ball groove at only one point.

The input and output yokes 11.12 are assembled with a joint angle α, and the balls 13.14 are respectively in grooves 15.16.
: It is held at each intersection of 17 and 18, and by always holding that position accurately, uniform velocity is maintained and smooth rotation is achieved.

When the joint angle α is small, the intersecting angles of the cooperating ball grooves are large by K on both sides A and B, and the ball is held almost exactly at the intersection of the ball grooves without any particular problem. However, when the joint angle α increases, the ball 14 located at B@ is held securely because the intersecting angle of the cooperating ball grooves 17 and 18 becomes large, but conversely, the ball 13 located on the B side is held together. Since the crossing angle of the working balls becomes extremely small, play occurs due to slight dimensional differences between the balls and the ball grooves.

In addition, the gap caused by slight elastic deformation of the yoke joint caused by the applied load also promotes play in the ball, which prevents the ball from being held accurately at the intersection of the ball groove of the output yoke during rotation, and prevents smooth rotation. becomes impossible.

This phenomenon becomes more pronounced as the joint angle α becomes steeper.

In short, when a Weiss type constant velocity joint is applied to an application where the joint angle is high and play in the rotational direction is a problem, such as a steering wheel joint for an automobile, the conventional Weiss type constant velocity joint is There is no problem with balls located on the B side of The disadvantage of not being able to rotate cannot be avoided.

In the worst case scenario, the unstable ball located on the opposite load side may fall off due to vibration during operation, causing a fatal problem for this type of constant velocity joylet.

Here, we will further consider the play of the ball in the Weiss type constant velocity join.

When the joint angle α is large, a gap is created between the ball 13 located on the side of the ball and the ball grooves 15 and 16 in FIG. 4a. The causes of this are the "difference in the radius of curvature between the ball and the ball groove" and the "minor elastic deformation of the yoke joint under load."

In order to stably use the Weiss-type constant velocity joint with
In other words, it is necessary to make the curvature of the ball groove provided in the yoke joint part relative to the ball 50.09GK.

However, with current processing technology, it is impossible to achieve ±OK machining accuracy for iron-based materials, which have a large elastic modulus.
Furthermore, even if tolerances are set, the elastic modulus of current steel materials is large, making it impossible to assemble with negative tolerances9.
This inevitably results in a positive tolerance. Therefore, the ball groove curvature is 50
．． 0- or more, and the higher the angle of use of the joint, the greater the play in the rotational direction.

[Problem that the invention seeks to solve]

In the present invention, after the joint is assembled, the ball groove and the ball formed in the yoke joint part are always pressed against each other to maintain the following state, and even if the joint angle is high, there is no play in the rotational direction and stable rotational performance can be obtained. Provides a constant velocity joint.

[Means and effects for solving the problem] According to the present invention, at least one of the ball of the constant velocity joint and the yoke joint portion having the ball groove for incorporating the ball is made of reinforced plastic with a small elastic modulus. At the same time as manufacturing, the elastic deformation during assembly of the ball groove and ball creates a pressure contact force at the contact area between the ball hexagram and the ball groove, thereby eliminating some variation in accuracy during processing (forming). Even if the reinforced plastic material is easily elastically deformed, stable performance can be obtained with a large difference in the amount of preload, and a constant velocity joint that can be used, for example, in a steering wheel for an automobile can be obtained.

Furthermore, when carrying out this invention, the constant velocity joint can be provided with sufficient strength by embedding a steel material inside the ball or yoke joint made of reinforced plastic.

[Example] Below, Figure 1 DJ! /r,p The present invention will be described based on an example with reference to FIG.

Figures 1a-c show cross-sectional views of the yoke joint of a constant velocity joint formed by embedding a steel material as a core bar 3 inside a reinforced plastic material, and the ball groove 2 in which the ball 1 is accommodated. When molded, the ball 1 is finished with a negative tolerance to its radius of curvature (Fig. 1a) or has an elliptical shape (Fig. 1b), and after the ball is inserted during assembly, the ball and ball groove are deformed due to elastic deformation. It is always in a pressure contact state, and in this embodiment, the ball groove curvature with respect to the ball is completely 50.
．． It is designed to be OIK (Fig. 1C). Note that it is also possible to make the ball groove not a circle but a quadratic curve such as a hyperbola.

As shown in FIGS. 2a and 2b, a core bar 4 made of steel is embedded inside the yoke joint part 5 made of reinforced plastic.
The yoke joint is reinforced and the amount of preload is adjusted. In addition, in Fig. 2a, by changing the diameter of the ball 6, it is possible to apply preload by elastic deformation of the reinforced plastic part in which the core metal is embedded, and by utilizing the small elastic modulus of the reinforced plastic material, processing is possible. Even if a difference occurs in the elastic deformation layer of the reinforced glass part due to variations in accuracy, the variation in the amount of preload can be reduced.

Furthermore, in Figure 2, there is a slit 7 in the yoke joint.
The preload is applied by using the elastic deformation of the yoke joint, and by changing the shape of the core metal part and reinforced plastic part, the apparent elastic modulus is adjusted to achieve the optimal preload. By getting the quantity?

Wear.

Figure 3 shows a ball 6 made of reinforced plastic with a steel ball 6' as a core material embedded inside the ball 6 made of reinforced plastic.
The same effect as in Figures a and b can be obtained. Of course, the yoke joint portion or the ball may be formed only of reinforced plastic.

Furthermore, although the Weiss type constant velocity joint has been described in the above embodiment, the present invention is also applicable to other types of constant velocity joints using balls, such as the Tetsuppa type constant velocity joint.

〔Effect of the invention〕

As described above, in the present invention, at least one of the ball and yoke joint parts is made of a reinforced plastic material, and the ball is pressed into contact with the ball groove formed in the joint part during assembly, so that the elastic modulus is By using a reinforced plastic material with a small diameter, the ball is accommodated in the ball groove without play, making it easy to adjust the amount of preload.
As a result, rotation can be reliably and smoothly transmitted from the input-side yoke to the output-side yoke even if the joint angle becomes high.

(9) When a steel material is buried as a core metal, not only is it easy to adjust the amount of preload, but also the strength can be improved.

[Brief explanation of drawings]

Figure 1 a''-c is a person with a constant velocity joint according to the present invention,
FIG. 3 is a cross-sectional view of the ball groove portion of the output yoke. FIGS. 2a and 2b are sectional views of the ball holding part. FIG. 3 is a sectional view of another ball holding part of the present invention. FIG. 4a is a side view of a conventional Weiss type constant velocity joint, and FIG. 4b is a sectional view showing the relationship between the ball and the ball groove. 1...Ball 2...Ball groove 3.4...Core metal 5...Yoke joint part 6...Ball 6'
...Steel ball 7...Slit

Claims (2)

[Claims] (1) At least one member of the yoke joint having a ball and a ball groove for incorporating the ball is made of reinforced plastic with a small elastic modulus, and the ball and the ball are elastically deformed when the ball is assembled with the ball groove. A constant velocity joint characterized by generating a pressure contact force at the contact portion of the ball groove. (2) A constant velocity joint according to claim 1, characterized in that a core metal made of steel is embedded inside a ball or yoke joint made of reinforced plastic.