KR101814612B1

KR101814612B1 - Ball joint and manufacturing method of the same

Info

Publication number: KR101814612B1
Application number: KR1020160006134A
Authority: KR
Inventors: 이재형; 이윤건; 박인희; 손남익; 유병석
Original assignee: 주식회사 일진
Priority date: 2016-01-18
Filing date: 2016-01-18
Publication date: 2018-01-04
Also published as: KR20170086372A

Abstract

A ball joint according to the present invention includes a ball stud including a ball and a stud, a bearing coupled to the outer circumferential surface of the ball and having a protrusion formed on an upper surface thereof, a ball casing accommodating the ball and the bearing therein, And an insert, which is filled in the ball casing and is integrally coupled to the ball casing and the bearing, wherein the bearing is disposed outside the radius of the protrusion, As shown in FIG. Accordingly, the molten resin can be injected in a state where a part of the upper surface of the bearing and the lower end surface of the injection core are in contact with each other, thereby fixing the position of the bearing.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a ball joint,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball joint and a method of manufacturing the ball joint, and more particularly, to a ball joint having improved stability of a bearing and a manufacturing method thereof.

BACKGROUND ART [0002] Generally, a suspension of a vehicle is a device for connecting a vehicle body and a wheel. The suspension includes a spring for absorbing vibration or shock transmitted from the road surface to the vehicle body, a shock absorber for controlling the operation of the spring, .

Suspension arms or links of such suspensions can be moved relative to the vehicle body or wheels by ball joints or ball joints.

A conventional ball joint is a structure in which a ball of a ball stud is rotatably inserted into a housing. The ball joint includes a ball and a ball stud made of a rigid body, a housing or a case surrounding the ball stud and a ball stud interposed between the housing and the ball stud. Bearings for free movement, and dust covers to prevent foreign matter from entering the interior of the housing.

The above conventional ball joint is usually manufactured through the following series of processes.

First, the case is placed on the bottom plate of the mold, the bearing is mounted on the ball, and then inserted into the bottom plate of the mold so as to penetrate the upper case. Thereafter, the upper plate of the mold is closed, and the molten resin is injected between the respective molds to insert injection. Then, the mold is opened and the dust cover is assembled to the ball stud.

However, in the process of injecting the molten resin between the respective molds in the above-described conventional ball joint manufacturing process, as the bearing is merely assembled to the ball and the injection pressure of the molten resin is received, If the molten resin is injected in such a state that the bearing is twisted, for example, the ball joint may fail to be formed, resulting in premature wear of the bearing and durability of the ball joint. . Particularly, when the bearing is assembled to the ball, the approximate position of the bearing is adjusted depending on the manual operation, making it difficult to precisely assemble the bearing.

SUMMARY OF THE INVENTION The present invention is conceived in view of the above circumstances, and it is an object of the present invention to provide an injection pipe having a relatively small diameter inside an injection core passing through a mold upper plate and forming a guide lip on the bearing, And to provide a method of manufacturing the ball joint.

According to an aspect of the present invention, there is provided a ball joint comprising: a ball stud including a ball and a stud; A bearing coupled to surround the outer circumferential surface of the ball and having a protrusion formed on an upper surface thereof; A ball casing accommodating the ball and the bearing therein; And an insert that is filled in the ball casing and is integrally coupled to the ball casing and the bearing, wherein the bearing is provided with a plurality of guide ribs extending radially outward of the protrusion and extending in the height direction, And is formed by a plurality of openings.

A plurality of inflow grooves are formed in the upper edge of the protrusion along the circumferential direction, and each of the inflow grooves communicates with an inflow passage formed between the guide ribs.

The angle between the guide ribs may be the same along the circumferential direction.

And the inflow grooves are disposed between the circumferential directions of the guide ribs.

A method of assembling a ball joint according to an embodiment of the present invention includes the steps of pressing a ball stud into a bearing, inserting a ball casing into a lower mold, inserting the ball stud into the ball casing, closing the upper mold, A first injection step of injecting a molten resin into the lower and upper molds and solidifying the insert with the insert; A second injection step of injecting the molten resin into the remaining space inside the lower and upper molds; And assembling a dust cover on the ball stud, wherein in the first primary injection step, the injection core is lowered so that the bearing is fixed so that a part of the upper surface of the bearing and a lower end surface of the injection core Thereby maintaining the contact state.

The lower end surface of the injection core is formed to be horizontal, the upper surface of the guide lip is flat, and the lower end surface of the injection core contacts the upper surface of the guide lip to adjust the position of the bearing to a proper position . &Lt; / RTI >

In the first injection step, the molten resin of the injection core flows into the lower mold through the inflow passages formed between the guide ribs.

The molten resin is injected to the upper side in the height direction at least above the center of the ball in the first injection step and a part of the bearing is coupled to the ball casing in the process of solidifying the molten resin with the insert have.

The injection core is provided with an injection pipe inserted inside the radius thereof and adapted to inject the molten resin, and the injection pipe is fixed at a heightwise position with a predetermined height.

In the second injection step, the injection core is raised by a lower end position of the injection tube so that a larger amount of molten resin is injected than the first injection step.

As described above, according to the ball joint and the manufacturing method thereof according to the embodiment of the present invention, since the molten resin is uniformly discharged through the respective molds while the position of the bearing is fixed, even if the bearing receives the injection pressure of the molten resin It is possible to maintain the correct position without backlash. Therefore, the operability and durability of the ball joint can be ensured.

1 is a cross-sectional view showing a first process step of a method of manufacturing a ball joint according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a bearing of a ball joint according to an embodiment of the present invention.
3 is a cross-sectional view showing a second process step of a method of manufacturing a ball joint according to an embodiment of the present invention.
4 is a cross-sectional view showing a third process step of a method of manufacturing a ball joint according to an embodiment of the present invention.
5 is a cross-sectional view showing a fourth process step of a method of manufacturing a ball joint according to an embodiment of the present invention.
6 is a cross-sectional view showing a fifth process step of a method of manufacturing a ball joint according to an embodiment of the present invention.
7 is a cross-sectional view showing a sixth process step of a method of manufacturing a ball joint according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

The parts denoted by the same reference numerals throughout the specification mean the same or similar components.

FIG. 1 is a cross-sectional view showing a first process step of a method of manufacturing a ball joint according to an embodiment of the present invention, FIG. 2 is a sectional view showing a bearing of a ball joint according to an embodiment of the present invention, FIG. 4 is a cross-sectional view showing a third process step of a method of manufacturing a ball joint according to an embodiment of the present invention, and FIG. 5 is a cross- 6 is a cross-sectional view showing a fifth process step of a method of manufacturing a ball joint according to an embodiment of the present invention, and Fig. 7 is a cross-sectional view of a ball joint according to an embodiment of the present invention. Sectional view showing a sixth process step of a method of manufacturing a ball joint according to an embodiment.

1 to 3, a ball joint according to an embodiment of the present invention includes a ball stud 10 made of a rigid body, a bearing 20 for freely supporting the movement of the ball stud 10, 10 and a ball casing 30 for receiving the bearing 20. [

FIG. 1 shows the first process step. In the first process step, the ball stud 10 is press-fitted into the bearing 20. The bearing 20 is disposed concentrically with the center of the ball 12. The bearing 20 includes a protrusion 21 protruding upward from the upper surface of the bearing 20 and a plurality of guide ribs 210 disposed on the side of the protrusion 21, .

1 and 2, the projecting portion 21 is formed in a substantially cylindrical shape, and an inflow groove 200 is formed along the outer peripheral surface thereof. The inflow groove 200 is formed at the corner of the upper surface of the protrusion 21 so that the upper surface and a part of the side surface of the protrusion 21 are opened. As described below, the molten resin is injected into the upper inflow groove 200, and the shape of the inflow groove 200 is formed into a curved shape so that the molten resin can flow smoothly along the outer circumferential surface of the bearing 20 .

The guide ribs 210 extend in the height direction of the ball stud, and are generally formed in the shape of a plate. The guide ribs 210 are formed to be spaced from each other along the circumferential direction on the side of the protruding portion 21 and the upper surface of the bearing 20. One guide lip 210 is spaced apart from one another to define an inlet passage 220 together with the other guide lip 210 and communicates with a part of the upper inlet groove 200. Accordingly, the molten resin flowing along the inflow groove 200 descends along the inflow passage 220 on the outer circumferential surface of the bearing 20. To this end, the upper inflow groove 200 is disposed between the circumferential directions of the guide ribs 210.

In addition, the respective inflow grooves 200 and the guide ribs 210 are formed along the circumferential direction while maintaining a constant angle between them.

For example, as shown in Figs. 1 and 2, four inflow grooves 200 are formed in the protruding portion 21 of the bearing 20 so as to be spaced apart from each other at an angle of 90 degrees along the circumferential direction, The guide ribs 210 are spaced apart from each other by a distance of 30 degrees along the circumferential direction so that the respective inflow grooves 200 are spaced apart from each other by the inflow passages 220 formed between the guide ribs 210 As shown in Fig.

On the other hand, a flat support surface 23 is formed on the upper surface of the guide ribs 210, and the position of the bearing 20 is adjusted through the support surface 23.

3 shows the second process step. In the second process step, a ball casing 30 previously made in the lower mold 60 is mounted and fixed, and then the ball 12 of the ball stud 10 is fixed to the bearing 20, the ball stud 10 is inserted into the ball casing 30.

In the third process step, referring to FIG. 4, the position of the bearing 20 is adjusted in a state where the upper mold 50 is closed.

In the upper mold 50, an opening hole is formed in the longitudinal direction of the ball stud 10, and the injection core 100 is inserted into the opening. An injection tube 120 having a diameter smaller than that of the injection core 100 extends in the longitudinal direction of the injection core 100 inside the injection core 100. The injection pipe 120 functions to inject molten resin between the upper mold 50 and the lower mold 60 through the injection path 110 formed in the inside of the hollow cylindrical shape.

Meanwhile, according to the embodiment of the present invention, the molten resin is injected through the upper injection pipe 120, but the present invention is not limited thereto. That is, an injection pin may be formed inside the injection core 100 so as to be radially inwardly spaced from the injection core 100, and the molten resin may flow between the outer peripheral surface of the injection pin and the inner peripheral surface of the injection core. For example, the injection pin may be formed in a circular columnar shape, and the molten resin may flow in the circumferential direction between the injection pin and the injection core 100.

The injection core 100 according to the embodiment of the present invention is installed to be movable up and down while the injection pipe 120 is fixed in the height direction.

When the injection core 100 is lowered, the lower surface of the injection core 100 comes into contact with the support surface 23 formed on the upper surface of the bearing 20, and the position of the bearing 20 is adjusted at this time. That is, when the lower surface of the injection core 100 and the support surface 23 of the bearing 20 are in contact with each other, the lower surface of the injection core 100 is formed to be horizontal to the paper surface. The upper surface is also horizontally adjusted to the ground. Therefore, the position of the center of the bearing 20 mounted on the upper surface of the vertical ball stud 10 on the ground can be arranged concentrically with the center of the ball 12. [

In the fourth process step, the first injection process is performed. The molten resin inside the injection pipe 120 flows into the inflow groove 200 of the protrusion 21 formed on the upper portion of the bearing 20 by the injection path 110 as shown in FIG. As described above, the guide ribs 210 are guided by the plurality of guide ribs 210 formed outside the radius of the protruding portion 21 to naturally ride on the outer peripheral surface of the bearing 20 along the inflow passages 220, And is injected into the gap between the molds 60. At this time, since the lower surface of the injection core 100 is in contact with the support surface 23 of the bearing 20, the position of the bearing 20 can be continuously fixed.

Therefore, the molten resin can be injected while the bearing 20 is fixedly mounted on the top of the ball stud 10, and the bearing 20 is held in the correct position.

In this case, since each of the inflow grooves 200 is formed along the circumferential direction while maintaining an angle between them, when the molten resin flows into the bearing 20, the center O of the ball 12 is formed, A uniform injection pressure in the circumferential direction is received. Therefore, even when the bearing 20 receives the injection pressure of the molten resin, it is possible to maintain the correct position without backlash. In addition, since the molten resin discharged to the upper inflow passage 220 has a relatively small flow rate, less injection pressure is generated, so that the twisting phenomenon of the bearing 20 can be suppressed.

On the other hand, in the first injection step, the molten resin is injected so as to enclose at least a part of the bearing 20. Suitably, the molten resin is injected up to or above the height of the center O of the ball 12. The molten resin thus injected is solidified in the insert 130 as shown in Fig. 5, and the first injection is performed. Therefore, by the solidification of the molten resin, the bearing 20 can be completely fixed while maintaining the correct position.

Thereafter, the fifth process step of FIG. 6 is performed, and a second injection process is performed. In the second injection step, the injection core 100 is moved upward by a set height while the injection tube 120 is fixed in the height direction. Thus, the molten resin is injected between the upper mold 50 and the lower mold 60 at a higher flow rate than the fourth process step. At this time, the molten resin flows until it is positioned at the tip of the injection tube 120. The molten resin is solidified into the insert 130 by the first injection process so as to join between the ball casing 30 and the bearing 20 so that the bearing 20 is prevented from being twisted or rotated, The second injection process can be performed while maintaining the same position of the process step. Therefore, the problem of defective forming of the ball joint can be solved.

7, in the sixth process step, the ball stud 10 from which the insert 130 is injected is demolded from the respective molds 50 and 60, and then the dust cover 70 is inserted into the ball stud 10 Process. At this time, the lubricant can be further injected, and the dust cover 70 can be attached to the ball stud 10 by the ring clip 52. Thereafter, the production of the ball joint is completed.

Meanwhile, in the ball casing 30 of the ball joint according to the embodiment of the present invention, the inner side surface 32 of the ball casing 30 may be provided with concave grooves and protrusions 34 in which the protrusions are continuous in the axial direction , The concave grooves and the protrusions may have a continuous structure in the circumferential direction. Then, the molten resin is inserted into the ball casing 30 and filled with the irregular portion 34, and then hardened by the insert 130. Therefore, the coupling between the ball casing 30 and the insert 130 can be increased. That is, the contact area between the ball casing 30 and the insert 130 is increased by the concave and convex portions 34 and the height of the ball casing 30 and the insert 130 due to the shape characteristic of the concave- The directional coupling is increased and there is no fear that the ball casing 30 and the insert 130 are separated in the axial direction.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

10: Ball Stud
12: Ball
14: Stud
20: Bearings
21:
30: Ball Casing
100: injection core
120: Injection pipe
130: insert
200: Inflow home
210: guide lip

Claims

A ball stud comprising a ball and a stud;
A bearing coupled to surround the outer circumferential surface of the ball and having a protrusion formed on an upper surface thereof;
A ball casing accommodating the ball and the bearing therein; And
An insert filled in the ball casing and integrally coupled to the ball casing and the bearing;
, &Lt; / RTI &
Wherein a plurality of guide ribs extending in the height direction are formed in the bearing on the outside of the radius of the protrusion along the circumferential direction,
Wherein the projecting portion is formed in a cylindrical shape,
And a flat support surface on which the lower end surface of the injection core is in contact is formed on the upper surface of the guide lip.

The method according to claim 1,
Wherein a plurality of inflow grooves are formed in the upper edge of the protrusion along the circumferential direction, and each of the inflow grooves communicates with an inflow passage formed between the respective guide ribs.

3. The method of claim 2,
And the angle between the plurality of guide ribs is the same along the circumferential direction.

The method of claim 3,
And the inflow groove is disposed between the circumferential directions of the guide ribs.

The method of manufacturing a ball joint according to any one of claims 1 to 4,
Pressing the ball stud into the bearing;
Attaching a ball casing to a lower mold and inserting the ball stud into the ball casing;
Closing an upper mold and inserting an injection core capable of moving up and down in the upper mold to adjust a position of the bearing;
A first injection step of injecting a molten resin into the lower and upper molds and solidifying the molten resin with an insert;
A second injection step of injecting the molten resin into the remaining space inside the lower and upper molds; And
Assembling a dust cover on the ball stud;
, &Lt; / RTI &
Wherein in the first injection step, the injection core is lowered so that the bearing is fixed so that a part of the upper surface of the bearing and a lower end surface of the injection core are kept in contact with each other.

6. The method of claim 5,
The lower end surface of the injection core is formed to be horizontal, the upper surface of the guide lip is flat, and the lower end surface of the injection core contacts the upper surface of the guide lip to adjust the position of the bearing to a proper position Wherein the ball joint is manufactured by a method of manufacturing a ball joint.

The method according to claim 6,
Wherein in the first injection step, the molten resin of the injection core flows into the lower mold through the inflow passages formed between the respective guide ribs.

8. The method of claim 7,
Wherein in the first injection step, the molten resin is injected to at least the upper side in the height direction of the center of the ball, and a part of the bearing is coupled to the ball casing in the process of solidifying the molten resin with the insert. Joint manufacturing method.

8. The method of claim 7,
Wherein the injection core is provided with an injection pipe inserted inside the radius thereof and adapted to inject the molten resin,
Wherein the height of the injection pipe is fixed at a predetermined height.

10. The method of claim 9,
In the second injection step
Wherein the injection core is raised by a lower end position of the injection tube so that a larger amount of molten resin is injected than the first injection step.