JPH0221445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball joint in which a reinforced plastic socket is adhered to the outer periphery of the spherical head of a ball stud through a bearing shell having an oil groove serving as a lubricating oil passage.

In a method of manufacturing a ball joint, it is known to directly pour a bearing layer onto the outer periphery of a ball stud, and then to form a socket by die casting or injection molding (resin) around the outer periphery of the ball stud having the bearing layer.

In this case, in order to generate appropriate sliding characteristics between the ball stud and the bearing, an operation is performed as a post-process to create a gap between the outer periphery of the ball stud and the bearing layer, but in the case of a resin bearing layer, In the case of a metal bearing layer, this gap cannot be formed due to the elasticity of the resin itself, and in the case of a metal bearing layer, the ball stud cannot be maintained at an appropriate preload state due to plastic deformation of the metal. It was difficult to maintain it.

Therefore, an object of the present invention is to manufacture a ball joint as described above by covering the head of the ball stud with an oil grooved bearing shell and pouring reinforcing plastic onto it to form a socket part. To obtain a lightweight ball joint capable of maintaining a ball stud in a preloaded state, providing a contact part between the ball stud and a bearing where lubricating oil can be easily inserted, and realizing stable starting and operating torque for a long period of time.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a ball joint 6 according to an embodiment of the present invention.
In the figure, reference numeral 6 indicates a ball joint, which is composed of a socket 18, a ball stud 7, and a bearing shell 11. 1 is a shaft connecting member fixedly connected to a ball stud 7 with a nut 5; 2 is a socket connecting member connected to the socket 18;

3 is a dust cover whose large diameter end is fixed to the outer periphery of the socket opening 19 by a snap ring, and whose small diameter end with a reinforcing ring is adapted to the handle 8 of the ball stud 7. 4 is lubricating oil sealed in the dust cover 3.

As shown in FIGS. 2 and 3, the bearing shell 11 is composed of a cylindrical body shell 12 and a dish-shaped top shell 13, and has a ball stud spherical head on its inner periphery. It has a spherical surface 16 that fits around the outer circumference of the section 10 and supports the spherical head 10. This spherical surface 16 has oil grooves 17 that serve as passages for the lubricating oil 4.
Several oil grooves are formed from the opening to the center of the inner bottom, and the oil grooves 17 communicate with each other to the center of the inner bottom. On the other hand, the outer periphery of the bearing shell 11 is provided with a plurality of protrusions 14, 1 that prevent rotation of the bearing shell 11 within the socket.
5 is formed.

The body shell 12 and the top shell 1 of this bearing shell 11
3 is made of a resin material such as nylon or polyacetal, and is separately molded by being divided along the horizontal plane along the line A-A.

Note that the bearing shell 11 is not limited to the above-mentioned embodiment; as shown in FIG. 6, oil grooves 17a are formed in the inner periphery of the bearing shell 11a in a mesh shape, and the overall surface is spherical with individual fine bearing surfaces 16b. 16
It is also possible to form a. The bearing shell 11 may be formed by integrally molding the body shell 12 and the top shell 13 without dividing them.

As shown in FIG. 4, the ball stud 7 has a handle 8 made of steel, a spherical head 10 at one end of the handle 8, and a male threaded part 9 at the other end. This ball stud 7 is held by a bearing shell 11 and a socket 18 so that it can freely rotate around its axis and swing around its spherical head 10.

In addition, the change in the space volume inside the dust cover 3 caused by the rocking motion of the ball stud 7 produces a lubricating oil supply action, which is generally referred to as the breathing action of the dust cover. Lubricating oil 4 is supplied through groove 17.

The socket 18 surrounds the outer periphery of the ball stud spherical head 10 surrounded by the bearing shell 11, and allows the ball stud handle 8 to swingably protrude from an opening 19 formed at one end in the axial direction of the socket.

This socket 18 is molded from a reinforced plastic material made by mixing a thermosetting resin with a suitable reinforcing material such as glass fiber or carbon fiber, and the mixing ratio of the reinforcing material is appropriately determined to satisfy the required socket strength. Ru.

The reinforced plastic of the socket material is a resin having a melting point lower than that of the bearing shell 11, such as a phenolic resin. This is because the bearing shell may melt due to the molding temperature (melting temperature) of the socket.

Note that even if grease is applied as lubricating oil 4 to the inside of the bearing shell 11 before pouring into the socket, the heat generated during pouring will destroy the soap base (stone fiber) of the grease, making it impossible to retain the oil, and the lubrication function will be lost. It is clear that there is a significant decline.

Next, the manufacturing process of the ball joint will be explained.

As the first step, the bearing shell 11 shown in FIG. 2 is formed into the body shell 1 by ordinary injection molding.
2 and a top shell 13.

As a second step, the bearing shell 11 formed in the first step is placed over the ball stud spherical head 10 as shown in FIG.
0, and the trunk shell 12 and the top shell 13 are high-frequency welded on a plane along the line A-A shown in FIG. 2 to form an integral bearing shell.

As a third step, as shown in FIG. 5, the ball stud 7 with the bearing layer formed in the second step is
It is placed in a mold 25 having the same cavity 26 as the desired ball joint socket 18, and the bearing shell 11 is integrally covered by the socket 18 by pouring reinforcing plastic.

In addition, before pouring this reinforced plastic,
The male threaded part 9 of the ball stud 7 is attached to the fixing jig 2 in advance.
The opening of the bearing shell 11 is also closed at the other end surface of the fixing jig 20, and the fixing jig 20 has a flange 23 on the outer periphery. Upper mold 27 and lower mold 28
The ball stud 7 is positioned and fixed in the mold 25 by these grooves 29.

Ball joint 6 manufactured in this way
Then, as shown in FIG. 1, a dust cover 3 is attached, lubricating oil 4 is enclosed, and the device is connected to the connecting members 1 and 2 depending on the purpose of use. The sealed lubricating oil 4 is
The aforementioned breathing action of the dust cover 3 supplies oil through the oil groove 17 of the bearing shell 11 to the sliding surfaces of the spherical surface 16 of the shell and the ball stud spherical head 13, thereby lubricating the space therebetween.

Furthermore, when the socket 18 is injection molded as described above, the bearing shell 11 receives compressive force from the outer periphery due to molding contraction of the socket resin and holds the ball stud spherical head 10 in a preloaded state, so that the desired ball stud activation and Operating torque can be obtained. The ball stud starting and operating torque can be adjusted by the molding shrinkage rate of the socket resin and the molding pressure of the socket.

As described above, in the present invention, a bearing shell with an oil groove is placed over the head of a ball stud, and a reinforced plastic having a melting point lower than that of the bearing shell is poured onto it to integrally form a socket part. The pull-out load of the bearing shell against the socket is increased, the bearing shell does not fall out of the socket, and an oil groove is provided that supplies lubricating oil between the ball stud and the bearing shell, for example, by the breathing action of the dust cover. Moreover, the molding shrinkage of the socket resin during socket molding generates a compressive force in the resin bearing shell that holds the ball stud in a preloaded state, so when using a ball joint, the effect of the oil groove mentioned above allows for stable long-term stability. Ball stud starting and operating torque can be achieved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially sectional plan view of the ball joint in use.
Figure 2 is a cross-sectional view of the bearing shell. Figure 3 is a bottom view of the bearing shell. FIG. 4 and FIG. 5 are explanatory diagrams of the ball joint manufacturing process. FIG. 6 is a partially sectional plan view showing another embodiment of the bearing shell. (Explanation of symbols), 6...Ball joint. 7
...Ball Stud. 10... Spherical head. 11...
...Bearing shell. 16... Spherical surface. 17...Oil groove. 18...Socket. 25... Molding mold. 26...
... Cavity.

Claims (1)

[Claims] 1 has a spherical surface 16 on the inner periphery that fits the outer periphery of the ball stud spherical head 10, and the spherical surface 16
a first step of forming a resin bearing shell 11 having an oil groove 17 serving as a lubricating oil passage;
A second step of covering the ball stud head 10 with the bearing shell 11 formed in the step to surround the ball stud head 10, and applying the ball stud 7 with the bearing layer formed in the second step to the desired ball joint. Cavity 2, which is the same as the socket 18
6, and a reinforced plastic having a melting point lower than that of the bearing shell 11 is poured into the mold 25, thereby forming the bearing shell 11 integrally with the socket 18. A method for manufacturing a ball joint characterized by the following.