JPH1113740A - Ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve a problem wherein the number of constituting parts of a conventional ball joint is high, there is a need to increase precision on the respective parts and combination of the parts, a part cost and an assembly cost are high. SOLUTION: A ball joint comprises a cup-form housing 1 made of a metal integrally coupled to the tip of a rod 2 made of a metal; a sheet 6 made of synthetic resin cast in the housing 1 and having a spherical recessed surface 9 opened to a central part and having an opening formed in an upper surface having size lower than a maximum inside diameter; and a ball stud 11 made of a metal having a spherical part 12 integrally formed at a tip and tightly and rotatably fitted in the spherical recessed part 9. Since the ball joint consists of the sheet 6 cast in the housing 1 and a ball stud 11, the number of parts is reduced and manufacture at a low cost is practicable, and since the spherical recessed surface 9 of the sheet 6 is molded, an effect is produced such that the degree of roundness is high, tight engagement with the spherical part 12 of the ball stud 11 is practicable, a play is low, and rotation and oscillation are smoothly effected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball joint for connecting two links freely by relative rotation and swinging using a sphere.

[0002]

2. Description of the Related Art In a conventional ball joint, as shown in FIG. 10, a rod b is welded to a metal housing a.
A synthetic resin ball sheet c is placed over the spherical portion e of the ball stud d and fitted into the housing a, and then the bottom cover i is swaged. The dust boot f is inserted into the groove h formed in the housing a, and the ring boot g is used. The parts are fixed and the number of parts is large, so that the parts cost and the assembling cost are high. In particular, the housing is made of metal and has a complicated shape, so that the cost is high.

Further, if there is play in the combination of the parts, the rigidity of the ball joint is reduced, so that the ball seat c is often pressed into the housing a, and the inner diameter of the housing a and the inner and outer diameters of the ball seat c are often increased. Variations such as this lead to deterioration of the rotation and swinging performance of the ball joint, and in particular, there is a problem that the housing a tends to be distorted by welding the rod b.

[0004]

The problem to be solved by the present invention is that the conventional ball joint has many components, and it is necessary to increase the precision of each component and the combination of each component. That is, the assembling cost is high.

[0005]

As a means for solving the above-mentioned problems, a ball joint according to the first aspect of the present invention has a metal cup shape integrally connected to a tip of a metal rod. And a synthetic resin sheet in which a spherical concave surface whose opening on the upper surface that is cast into the housing and opened to the center is smaller than the maximum inner diameter,
A metal ball stud in which a spherical portion integrally formed at the tip is tightly and freely rotatably fitted to the spherical concave surface, comprising a housing, a cast-in seat and a ball stud. Because the number of parts is small, it can be manufactured at low cost, and the internal diameter of the housing may be low in accuracy, thereby reducing the processing cost. In addition, the metal cup-shaped housing is made of synthetic resin Since the sheet is surrounded, the sheet is protected from stepping stones and the spherical concave surface of the sheet is molded, so it has a high sphericity and can fit tightly with the spherical part of the ball stud. Therefore, there is an effect that the play is small and the rotation and the swing are smoothly performed. The ball joint according to the second aspect of the present invention is different from the ball joint according to the first aspect in the housing. A hole with a non-circular cross section is formed at the bottom, and the synthetic resin pillar portion integral with the synthetic resin forming the sheet is integrally formed in the hole, so that the sheet is prevented from tumbling with the ball stud. The ball joint according to the third aspect of the present invention has an effect, and in the ball joint according to the second aspect of the present invention, since the pillar is integrally formed with the projection in contact with the outer surface of the housing, the seat is prevented from coming off from the housing. According to the ball joint of the fourth aspect of the present invention, a circumferential groove is formed on the inner peripheral surface of the housing in a direction substantially perpendicular to the opening direction of the housing. Since the circumferential groove is filled with the synthetic resin constituting the seat, the same effect as the ball joint according to the third aspect of the invention is obtained. In the ball joint according to the first aspect of the present invention, since an annular projection is formed on the opening edge of the housing and the synthetic resin forming the sheet covers the annular projection, the upper portion of the sheet falls down inside after molding to remove the ball stud. There is an effect that the rotation torque of the ball stud can be prevented from increasing due to the tightening. In the ball joint according to the sixth aspect, the spherical portion of the ball stud is cast into the seat in the ball joint according to the first aspect. Since the spherical concave surface of the sheet is molded following the spherical portion of the ball stud, there is an effect that the spherical portion and the spherical concave surface are tightly fitted and smoothly rotate and swing without play,
The ball joint according to the seventh aspect of the present invention is such that the spherical portion of the ball stud is press-fitted in the seat in the ball joint according to the first aspect of the invention, and has an effect of being easily assembled and being manufactured at low cost.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2, reference numeral 1 denotes a cup-shaped housing made of metal such as steel fixed to the tip of a rod 2 made of metal such as steel by welding, and a hole 3 having a square cross section is formed at the bottom thereof. While being formed, a circumferential groove 4 is formed at the upper part of the inner peripheral surface, and an annular protrusion 5 is formed at the opening edge.

Reference numeral 6 denotes a synthetic resin sheet which is cast into the housing 1 by injection molding.
A column 7 filled in the hole 3 and a protrusion 8 protruding from the column 7 and in contact with the outer surface of the housing 1 are formed, and the circumferential groove 4 is also filled with a synthetic resin. The annular projection 5 is molded so as to wrap the synthetic resin.
Is formed, and a spherical concave surface 9 having a diameter larger than that of the opening portion connected to the tapered surface 10 is formed at the center.

Reference numeral 11 denotes a ball stud, and a spherical portion 12 formed at the lower end thereof is fitted in the spherical concave surface 9 of the seat 6 tightly and freely in rotation and swinging.

As described above, since the pillar 7 integral with the seat 6 is fitted into the square hole 3 of the housing 1, the seat 6 is prevented from hanging around with the ball stud 11,
Since the protrusion 8 protruding from the pillar portion 7 is in contact with the outer surface of the housing 1 and the circumferential groove 4 is filled with a synthetic resin integral with the sheet 6, the sheet 6 may come out of the housing 1. Further, since the annular protrusion 5 of the housing 1 is wrapped with the synthetic resin integral with the sheet 6, it is possible to prevent the upper portion of the sheet 6 from falling inward after molding and increasing the rotational torque of the ball stud 11. .

The spherical portion 12 of the ball stud 11 may be elastically deformed by strongly pressing the spherical portion 12 into the opening of the spherical concave surface 9 of the seat 6 to fit the spherical portion 12 into the spherical concave surface 9. The spherical portion 12 of the ball stud 11 may be cast in the sheet 6 by injecting a synthetic resin while holding the spherical portion 12 in the mold at the center of the housing 1.

Here, in order to prevent the synthetic resin from adhering to the spherical portion 6, the synthetic resin material contains potassium stearate or barium stearate in an amount of 0.5 to 1.0% by weight.
It is preferable to mix them to the extent that the spherical portion 6 of the ball stud 5 and the spherical concave surface 4 of the holder 3 can be slidably improved.

Further, a lubricant such as molybdenum disulfide (MoS ₂ ) or graphite is applied to the spherical portion 12 of the ball stud 11 and then cast with a synthetic resin. When a lubricant film is formed,
The slidability between the spherical portion 12 and the spherical concave surface 9 is further improved.

The synthetic resin material forming the sheet 6 has a shrinkage ratio and a shrinkage direction ratio during molding (a ratio of the shrinkage ratio in the direction perpendicular to the shrinkage ratio in the injection direction of the synthetic resin during injection molding).
Is required from a functional point of view, and in that regard, aromatic polyamide (MXDPA) has a shrinkage of about 0.28 to 0.28.
At 0.3%, the shrinkage direction ratio is 1.07, and the liquid crystal polymer (LCP) has a shrinkage ratio of about 0% and a shrinkage direction ratio of about 1, which is extremely small, and is suitable as a material for the sheet 6. .

In the embodiment shown in FIG. 3, an inward flange 1a is formed at the upper end of the housing 1 to prevent the seat 6 from coming out of the upper side. If it is polygonal, the seat 6 will not rotate.

The housing 1 shown in FIG. 4 has a polygonal inner peripheral surface, and serves as a detent for a sheet cast therein.

The housing 1 shown in FIG. 5 is provided with a polygonal protruding wall 1b on the outer periphery of the upper edge.
By wrapping the sheet and casting the sheet, the sheet is prevented from rotating.

In this embodiment, instead of providing the polygonal projection wall 1b on the outer periphery of the upper edge of the housing 1, a polygonal projection wall may be provided on the inner periphery of the upper edge.

In the embodiment shown in FIG. 6, the rods 2 are integrally cast at the projecting portions 6a when the sheet 6 is cast.

In the embodiment shown in FIG. 7, a plurality of holes 3 are formed in the housing 1. By forming the projections 8 when the sheet 6 is cast, the sheet 6 is prevented from rotating and coming off. .

The housing 1 shown in FIG. 8 has a plurality of embossed portions 1c formed on the peripheral surface. By wrapping the embossed portion 1c and casting a sheet, the sheet is prevented from rotating and coming off.

The housing 1 shown in FIG. 9 has a reduced diameter portion 1d formed by squeezing the upper portion, and serves to prevent the sheet from coming off.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of another embodiment.

4A and 4B show another embodiment of the housing, wherein FIG. 4A is a plan view and FIG. 4B is a sectional view.

FIGS. 5A and 5B show another embodiment of the housing, wherein FIG. 5A is a plan view and FIG.

6A and 6B show another embodiment, in which FIG.
(B) is a side view.

7A and 7B show another embodiment, in which FIG.
(B) is a perspective view of the housing.

FIG. 8 is a sectional view of another embodiment of the housing.

FIG. 9 is a sectional view of another embodiment of the housing.

FIG. 10 is a sectional view of a conventional example.

[Explanation of symbols]

 1: Housing 2: Rod 3: Hole 4: Circumferential groove 5: Annular projection 6: Seat 7: Column part 8: Projection 9: Spherical concave surface 11: Ball stud 12: Spherical part

Claims (7)

[Claims] 1. A metal cup-shaped housing integrally joined to the tip of a metal rod, and a spherical concave surface whose upper surface opening cast into the housing and opened to the center is smaller than the maximum inner diameter. A sheet of synthetic resin on which is formed,
A ball joint comprising: a metal ball stud having a spherical portion integrally formed at the tip and tightly and rotatably fitted to the spherical concave surface. 2. A hole having a non-circular cross-section is formed at the bottom of the housing, and a synthetic resin pillar portion integral with the synthetic resin constituting the sheet is fitted into the hole in a tight manner. The ball joint according to claim 1, wherein 3. The ball joint according to claim 2, wherein a projection that contacts an outer surface of the housing is formed integrally with the pillar. 4. A circumferential groove in a direction substantially perpendicular to an opening direction of the housing is formed on an inner circumferential surface of the housing, and the circumferential groove is filled with a synthetic resin forming the sheet. The ball joint according to claim 1, wherein: 5. The ball joint according to claim 1, wherein an annular projection is formed at an opening edge of the housing, and a synthetic resin forming the seat covers the annular projection. 6. The ball joint according to claim 1, wherein said spherical portion of said ball stud is cast into said seat. 7. The ball joint according to claim 1, wherein the spherical portion of the ball stud is pressed into the seat.