JPS6246903Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a ball joint in which a stable operating torque of a ball stud can be obtained even if there are variations in dimensional accuracy during assembly by enclosing compressed fluid.

2. Description of the Related Art Conventionally, ball joints used in steering linkages and suspensions of automobiles and the like include those shown in FIG. 1, for example.

In FIG. 1, 1 is a ball joint socket, which has a screw hole 1a at its lower end for connecting with a link member.
A ball portion 4 of a ball stud 3 is slidably held inside the ball joint socket 1 via a bearing 2 made of a highly wear-resistant plastic. 2, the plate 5 is fitted, and the opening edge 5 of the ball joint socket 1 is crimped or squeezed as shown in the figure using roller crimping or the like, and the ball stud is fixed by the elastic force of the bearing 2 determined by the crimping or squeezing load. A specified operating torque is obtained by the sliding resistance between the bearing 3 and the bearing 2.

However, in such conventional ball joints, the bearing 2 is made of a plastic material with high wear resistance, and so the bearing 2 is a so-called low-elasticity member that is less deformed under the assembly load. Therefore, when the ball stud 3 is assembled by crimping or drawing the ball joint socket 1, the change in elastic force due to slight dimensional variations is large.

Therefore, unless the dimensional accuracy of the bearings and press-fit parts is improved, the operating resistance after assembly becomes too high or too low, making it difficult to obtain an appropriate operating resistance.

The present invention was devised in view of these conventional problems, and is a ball joint that can be assembled so that the operating torque of the ball stud remains within a specified range even if there are variations in dimensional accuracy of each part. The purpose is to provide

To achieve this objective, the present invention compresses fluid by interposing it between the bearing and the ball joint socket when the bearing holding the ball stud is press-fitted into the ball joint socket.
The desired operating torque is generated in the ball stud by the reaction force caused by the compression of this fluid, and fluctuations in operating torque due to dimensional variations are absorbed.

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 2 is a sectional view showing an embodiment of the present invention. First, to explain the structure, reference numeral 1 is a ball joint socket, which has a screw hole 1a at the bottom for connecting to another link member, and a cylindrical hole open at the top. A bearing 10 made of a low elasticity material such as plastic material is press-fitted into the inside of the butt 1 and slidably holds the ball part 4 of the ball stud 3, and the opening edge 6 is caulked through the plate 5. It is also press-fitted. The bearing 10 includes a crimped part 10a that is crimped to the inner periphery of the opening side of the ball joint socket 1, and a non-crimped part 10b that forms a cavity between the bottom of the cylindrical hole and the ball joint socket 1 as shown in the figure. The ball joint socket 1 has a structure in which a fluid 12 is sealed in the gap between the non-crimped portion 10b of the bearing 10 and the ball joint socket 1 in an assembled state in which the ball joint socket 1 is press-fitted into the ball joint socket 1 and the opening edge 6 is caulked.

FIG. 3 is an explanatory view showing how the bearing 10 is assembled to the ball joint socket 1 in the embodiment shown in FIG.
In this state, the bearing 10 fitted with the ball part 4 of the ball stud 3 is press-fitted, and the fluid 1
2 is compressed by press-fitting the bearing 10. In this way, in the process of press-fitting the bearing 10, the excess fluid 12 compressed above a certain pressure overcomes the elasticity of the bearing 10 and leaks out to the outside until the pressure reaches a certain pressure, so the compressed fluid at a constant pressure is obtained. The reaction force due to the compression of the fluid 12 determines the pressing force of the ball stud 3 against the ball portion 4 through the bearing 10 as a low elastic member, thereby determining the operating torque of the ball stud 3.

Next, the operation of the embodiment shown in FIG. 2 will be explained with reference to the graph shown in FIG.

Figure 4 shows the operating torque of the ball stud against the bearing press-fit allowance (horizontal axis) when the bearing is press-fitted into the ball joint socket by caulking with the compression of the fluid enclosed in it, as shown in Figure 1. Curve A shows the characteristics of the conventional structure.
The characteristic of the embodiment shown in FIG. 2 is shown by curve B.

In other words, in the case of a conventional ball joint that uses a bearing made of a low-elasticity member as is, the bearing press-fit allowance, that is, the change in operating torque with respect to the amount of deformation of the bearing, which is a low-elasticity member, is as shown by curve A. For example, if the variation in the bearing press-fitting allowance is within the range of dimensional accuracy shown in the diagram, the operating torque corresponding to the length in the vertical axis direction for points a ₁ and a ₂ There is a variation in the

On the other hand, in the embodiment shown in FIG. 2, the operating torque changes gradually as shown by curve B with respect to the increase in bearing press-fitting allowance. This change in curve B is because the fluid 12 is sealed below the bearing 10, so when the bearing 10 is press-fitted, the fluid 12 is first compressed, and the increase in elastic force with respect to the volume change due to the compression of the fluid becomes a linear change. When the compression force of the fluid 12 increases as the displacement increases, the bearing 10, which is a low-elasticity member, begins to undergo elastic deformation, and the change in operating torque with respect to the bearing press-fit displacement increases.

As is clear from the characteristics of the curve B according to the present invention shown in FIG. 4, the characteristics of the curve B according to the present invention have the same variation in bearing press-fitting allowance, that is, the range of dimensional accuracy as in the conventional case, between point b ₁ and point b ₂ . It only requires a change in the operating torque corresponding to the length of the vertical axis of the point, and even if there is variation in the same dimensional accuracy, the change in the operating torque can be significantly suppressed compared to conventional methods.
As a result, stable operating torque with little variation can be obtained without increasing the dimensional accuracy of the bearing 10, ball joint socket 1, etc.

FIG. 5 is a sectional view showing another embodiment of the present invention, and this embodiment is characterized by providing means for adjusting the amount of fluid sealed in the non-crimped portion of the bearing.

That is, an adjustment groove 14 extends above the non-crimped portion 10b of the bearing 10, so that when the bearing 10 is press-fitted into the ball joint socket 1 as shown in FIG.
The fluid 12 contained in the ball joint socket 1 passes through the adjustment groove 14 and escapes to the outside as shown by the arrow until the end of the adjustment groove 14 reaches the plate fitting part 15 formed in the opening of the adjustment groove. 14
When the fluid 12 reaches the plate fitting part 15, leakage of the fluid 12 is stopped and the amount of the fluid 12 to be compressed by press-fitting the bearing 10 is determined. Therefore, by appropriately determining the length of the adjustment groove 15, the amount of fluid 12 to be compressed by press-fitting the bearing 10 is determined, and the compression force of the fluid 12 is adjusted depending on the difference in fluid amount. The operating torque of the stud 3 can be determined arbitrarily.

FIG. 7 is a sectional view showing another embodiment of the present invention, and this embodiment is characterized in that a structure is provided on the non-pressure side of the bearing for partitioning and enclosing compressed fluid into a plurality of compartments. .

That is, a partition wall 16 shown in FIG. 8 or 9 is integrally formed on the bottom side of the non-crimped part of the bearing 10, and the bearing 10 is inserted into the ball joint socket 1 as shown in FIG. A compartment 18 is formed between the ball joint socket 1 and the ball joint socket 1 in a state where the opening edge 6 of the ball joint socket is compressed by press-fitting and the partition wall 16 encloses the compressed fluid.

According to the embodiment shown in FIG. 7, even if a pressing force is applied to the bearing 10 from the outside through the ball stud 3 while the ball joint is in use, the partition wall 16 prevents the bearing 10 from being placed inside the ball joint socket 1. Because it is supported by the fluid 1
The sealing pressure of 2 does not change, and a stable operating torque of the ball stud can be applied by the reaction force of the compressed fluid, and the fluid is compressed and sealed in the compartment 18 separated by the partition wall 16. Therefore, leakage of compressed fluid to the outside can be reliably prevented.

Next, to explain the effects of the present invention, fluid is sealed between the bearings that are press-fitted into the ball joint socket, and the sealed fluid is compressed by the assembly load obtained by caulking or squeezing the ball joint socket. Since the operating torque of the ball stud is obtained by applying a reaction force to the ball stud through the bearing, even if there is variation in the bearing press-fit allowance during assembly, it is not directly affected by the elastic deformation of the bearing member as in the conventional method. Compared to the case where operating torque is obtained from reaction force, it is possible to significantly reduce the variation in operating torque after assembly, and it is possible to obtain an appropriate operating torque within a specified range without increasing the dimensional accuracy of bearings and press-fit parts. ball joints with uniform operating torque can be mass-produced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example, Fig. 2 is a sectional view showing an embodiment of the present invention, Fig. 3 is an explanatory view showing fluid compression during assembly, and Fig. 4 is a sectional view showing an example of the present invention. 2
A graph diagram showing the relationship between bearing press-fit allowance and operating torque according to the embodiment shown in the figure in comparison with the conventional example, No. 5
The figure is a sectional view showing another embodiment of the present invention equipped with a groove for adjusting the amount of fluid to be press-fitted. Fig. 7 is a cross-sectional view showing another embodiment of the present invention in which the fluid enclosure is divided into a plurality of compartments, and Figs. 8 and 9 show the partition wall structure of the bearing forming the compartments in the embodiment of Fig. 7. FIG. 1...Ball joint socket, 3...Ball stud, 4...Ball portion, 5...Plate,
6...Opening edge, 10...Bearing, 10a...
...Crimp part, 10b... Non-crimp part, 12... Fluid,
14...Adjustment groove, 15...Plate fitting part, 16
...Partition wall, 18...Painting room.

Claims (1)

[Scope of Claim for Utility Model Registration] A ball joint for automobiles, etc., which slidably holds a ball stud, has a crimped part with the ball joint socket on the opening side into which the ball stud is inserted, and A bearing made of a low elasticity material has a crimped part on the bottom side of the joint socket, and when the bearing is press-fitted into the ball joint socket, a compressed state is created between the ball joint socket and the crimped part of the bearing. 1. A ball joint, characterized in that the ball joint is made up of a fluid sealed in the fluid, and a reaction force due to compression of the fluid generates a desired operating resistance in a ball stud via a bearing.