WO2020004947A1

WO2020004947A1 - Bush assembly, suspension arm comprising same and suspension arm manufacturing method

Info

Publication number: WO2020004947A1
Application number: PCT/KR2019/007754
Authority: WO
Inventors: 정세웅; 권익진; 김병환
Original assignee: 주식회사 일진
Priority date: 2018-06-26
Filing date: 2019-06-26
Publication date: 2020-01-02
Also published as: KR20200001065A; KR102100200B1

Abstract

A bush assembly provided to a suspension arm is provided according to one aspect of the present disclosure. The bush assembly may comprise: an outer pipe fixed to one side of a suspension arm; a bush bearing coaxially arranged with the axial direction of the outer pipe, and formed so as to be convex in the outer radial direction so that the cross-sectional diameter of the center portion is greater than the cross-sectional diameters of both side end portions; an insert member filled between the inner peripheral surface of the outer pipe and the outer peripheral surface of the bush bearing, and configured so as to fix the bush bearing to the inside of the outer pipe; and an inner pipe rotatably coupled to the bush bearing.

Description

Bush assembly, suspension arm comprising same, and method of making suspension arm

The present disclosure relates to a bushing assembly for use in a suspension of a vehicle, a suspension arm comprising the same, and a method of manufacturing the suspension arm.

The suspension of the vehicle is a device that connects the vehicle body and the wheels. The suspension may include a spring for absorbing vibrations or shocks transmitted from the road surface, a shock absorber for adjusting the operation of the spring, a suspension arm for controlling the operation of the wheel, or a suspension link.

Suspensions can be classified into swing arm type, wishbone type, and Macpherson strut type according to the method of controlling the operation of the wheel. The wishbone suspension device has a suspension arm that connects the knuckle engaged with the wheel to the vehicle body. That is, one end of the suspension arm may be connected to the cross member or subframe constituting the vehicle body, and the other end of the suspension arm may be connected to the knuckle through the ball joint. The suspension arm supports the wheel to the vehicle body and appropriately controls the toe-in of the wheel according to the driving condition of the vehicle, thereby improving the straight running and steering stability of the vehicle.

On the other hand, the suspension arm may have a mounting structure for connecting the wheel to the vehicle body in order to support the wheel with a proper degree of freedom with respect to the vehicle body. For example, a bushing assembly may be provided at the end of the suspension arm. The bush assembly may be made of a separate part and then press-fitted into the bush pipe fixed to the suspension arm.

Various embodiments of the present disclosure can provide a bush assembly integrally formed with a bush pipe of a suspension arm. It is also possible to provide a suspension arm comprising such a bush assembly. It is also possible to provide a method for producing a suspension arm comprising two insert injection processes.

A bush assembly installed on a suspension arm according to one aspect of the present disclosure, comprising: an outer pipe fixed to one side of the suspension arm; A bush bearing disposed coaxially with the axial direction of the outer pipe and having a convex shape in the outer radial direction such that the cross-sectional diameter of the central portion is larger than the cross-sectional diameter of both ends; An insert member filled between an inner circumferential surface of the outer pipe and an outer circumferential surface of the bush bearing to fix the bush bearing inside the outer pipe; And an inner pipe rotatably coupled to the bush bearing.

According to one embodiment, the insert member may be formed by insert injection of a thermoplastic polyurethane (TPU) material between the inner circumferential surface of the outer pipe and the outer circumferential surface of the bush bearing.

According to one embodiment, the bush bearing comprises: a first bush bearing fitted at one side of the inner pipe; And a second bush bearing fitted at the other side of the inner pipe and coupled to the first bush bearing.

According to one embodiment, the inner pipe is formed with a first protrusion configured to radially protrude in line contact with the inner circumferential surface of the first bush bearing and a second protrusion configured to radially protrude in line with the inner circumferential surface of the second bush bearing. Can be.

According to one embodiment, the first bush bearing comprises: a first seal forming a non-contact sealing structure with the inner pipe; A first contact configured to gradually increase in cross-sectional diameter from the first seal and to be in linear contact with the first protrusion of the inner pipe; A first seal portion extending from the first contact portion, wherein the second bush bearing includes: a second seal portion forming a non-contact sealing structure with the inner pipe on an opposite side of the first seal portion with respect to the cross-sectional center line of the inner pipe; A second contact configured to gradually increase in cross-sectional diameter from the second seal so as to be in linear contact with the second protrusion of the inner pipe; And a second center portion extending from the second contact portion to contact the first center portion.

According to one embodiment, the first inner circumferential region of the first bush bearing and the first outer circumferential region of the inner pipe form a first labyrinth structure, the second inner circumferential region of the second bush bearing and the second outer circumferential region of the inner pipe. May form a second labyrinth structure.

According to one embodiment, the first inner circumferential region of the first bush bearing includes a plurality of first protrusions protruding in the inner radial direction, and the first outer circumferential region of the inner pipe corresponds to the shape of the plurality of first protrusions. A first groove is formed, the second inner circumferential region of the second bush bearing includes a plurality of second protrusions projecting in the inner radial direction, and the second outer circumferential region of the inner pipe corresponds to the shape of the plurality of second protrusions. A plurality of second grooves may be formed to make it.

According to one embodiment, a lubricant may be filled in the space space formed by the first and second protrusions and the first and second central portions.

According to one embodiment, the first bush bearing includes a coupling portion extending in the axial direction from the outer circumferential surface of the first central portion to the second central portion and having coupling protrusions formed on the inner circumferential surface, such that the coupling protrusion is inserted into the outer circumferential surface of the second bush bearing. The configured coupling groove can be formed.

According to one embodiment, the radius of curvature of the outer circumferential surface of the first protrusion is configured to be smaller than the radius of curvature of the inner circumferential surface of the first contact portion in contact with the first protrusion, the radius of curvature of the outer circumferential surface of the second protrusion is in contact with the second protrusion It may be configured to be smaller than the radius of curvature of the inner peripheral surface of the second contact portion.

A suspension arm according to another embodiment of the present disclosure, comprising: an arm body made of a metal material; An insert molding part in which a first material is inserted into the arm body by insert injection; A ball joint fixed to one side of the arm body by insert injection; A bush assembly installed on the other side of the arm body, the bush assembly comprising: a bush pipe fixed to one side of the arm body; A bush bearing disposed coaxially with the axial direction of the bush pipe and having a convex shape in the outer radial direction such that the cross-sectional diameter of the central portion is larger than the cross-sectional diameter of both ends; An insert member configured to fill a second material between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing to fix the bush bearing inside the bush pipe; And an inner pipe rotatably coupled to the bush bearing.

According to one embodiment, the arm body includes: a joint portion having a coupling ring in which a ball joint is installed at the front end; And a leg portion formed with an injection hole extending from the joint portion, the bush pipe fixed to the tip, and insert injection of the first material.

According to one embodiment, the leg portion includes first and second leg portions extending from the arm body to both sides, the insert molding portion includes an injection hole in which the first material is formed in the first leg portion, an injection hole in the second leg portion; It may be formed by injection in a direction perpendicular to the first and second leg portion toward the three points including the coupling ring.

According to one embodiment, the insert member may be formed by injecting a second material in a direction parallel to the axial direction of the bush pipe.

According to one embodiment, the first material may be comprised of a PA6-GF50 material and the second material may be comprised of a thermoplastic polyurethane material.

In the manufacturing method of the suspension arm according to another embodiment of the present disclosure, a joint ring in which the ball joint is installed at the tip end is fixed to the joint part and the leg part extending from the joint part and the bush pipe is fixed at the tip part and the injection hole is formed. Manufacturing a cancer body comprising; Inserting the female body into the mold such that the ball joint is disposed in the coupling ring and the assembly of the bush bearing and the inner pipe is coaxially disposed with the bush pipe; Injecting the first material furnace toward the injection hole and the coupling ring in a direction perpendicular to the leg portion to form an insert molding portion; And injecting a second material between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing to form an insert member.

According to one embodiment, the step of inserting the arm body into the mold, the step of inserting the arm body into the mold so that the upper surface of the leg portion toward the injection position; Placing the ball joint in the engagement ring such that the bearing of the ball joint faces the ejection position; And disposing an assembly of the bush bearing and the inner pipe inside the bush pipe to be coaxially disposed with the bush pipe.

According to one embodiment, the second material may be injected at three spaced apart points between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing.

According to various embodiments of the present disclosure, insert injection of a TPU material between the bush bearing and the bush pipe may improve the durability of the bush assembly. In addition, since a process of injecting a separate steel pipe into the bush pipe of the suspension arm is not performed, the entire process can be simplified, and deformation and torque increase of the bush pipe can be suppressed.

1 is a perspective view illustrating a suspension arm according to an embodiment of the present disclosure.

2 is a perspective view illustrating a suspension arm in a direction different from that of FIG. 1 according to an exemplary embodiment of the present disclosure.

3 is an exploded perspective view illustrating an exploded configuration of the suspension arm shown in FIGS. 1 and 2.

4 is a cross-sectional view illustrating a structure in which the suspension arm shown in FIG. 2 is cut in the I-I direction.

5 is an exploded perspective view illustrating an exploded configuration of the ball joint shown in FIG. 4.

FIG. 6 is a cross-sectional view showing the structure in which the suspension arm shown in FIG. 2 is cut in the II-II direction. FIG.

7 is an exploded perspective view illustrating an exploded configuration of the bush assembly shown in FIG. 6.

FIG. 8 is an enlarged view illustrating an enlarged portion of the first bush bearing illustrated in FIG. 6.

9 is an enlarged view illustrating an enlarged portion of the second bush bearing illustrated in FIG. 6.

10 is a perspective view illustrating an assembly process of a bush bearing and an inner pipe and an assembly process of a ball stud and a bearing according to an exemplary embodiment of the present disclosure.

FIG. 11 is a perspective view illustrating a process of installing a bush bearing assembly and a bearing assembly in the arm body illustrated in FIG. 3.

FIG. 12 is a perspective view illustrating a process of forming an insert molding part by insert injection molding into an arm body assembly of FIG. 11.

FIG. 13 is a perspective view illustrating a process of forming an insert member by insert injection molding into an assembly of the arm body and the insert molding unit illustrated in FIG. 12.

FIG. 14 is a perspective view illustrating a process of insert injection two times in a state where the arm body assembly illustrated in FIG. 11 is inserted into a mold.

15 is a flowchart illustrating a method of manufacturing a suspension arm according to an embodiment of the present disclosure.

16 is a flowchart illustrating a step of inserting an arm body into a mold in the method of manufacturing a suspension arm according to an embodiment of the present disclosure.

1: suspension cancer

10: cancer body

20: insert molding part

100: bush assembly

110: bush pipe

120: first bush bearing

130: second bush bearing

140: no insert

150: inner pipe

Embodiments of the present disclosure are illustrated for the purpose of describing the technical spirit of the present disclosure. The scope of the present disclosure is not limited to the embodiments set forth below or the detailed description of these embodiments.

All technical terms and scientific terms used in the present disclosure have the meanings that are generally understood by those skilled in the art to which the present disclosure belongs unless otherwise defined. All terms used in the present disclosure are selected for the purpose of more clearly describing the present disclosure, and are not selected to limit the scope of the rights according to the present disclosure.

As used in this disclosure, expressions such as "comprising", "including", "having", and the like, are intended to include open terms, including the possibility of including other embodiments unless otherwise stated in the phrase or sentence in which the expression is included. -ended terms).

The singular forms recited in this disclosure may include the plural meanings, unless the context clearly indicates otherwise, which may likewise apply to the singular forms recited in the claims.

Expressions such as “first”, “second”, and the like used in the present disclosure are used to distinguish a plurality of components from each other, and do not limit the order or importance of the components.

In the present disclosure, when a component is referred to as being "connected" or "connected" to another component, that component can be directly connected to or connected to another component, or a new different configuration It may be understood that it may be connected or connected via an element.

The dimensions and numerical values described in the present disclosure are not limited only to the dimensions and numerical values described. Unless otherwise specified, these dimensions and values are to be understood to mean the values stated and the equivalent ranges encompassing them. For example, the dimension '3 mm' described in the present disclosure can be understood to include 'about 3 mm'.

Directional directives such as "upper" and "upper" used in the present disclosure are based on the direction in which the bushing bearing is positioned with respect to the inner pipe in the accompanying drawings, and directional directives such as "downward" and "lower" are reversed. Can mean direction. The bush bearing shown in the accompanying drawings may be otherwise oriented, and these direction indicators may be interpreted accordingly.

Hereinafter, embodiments of the present disclosure may be described with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding components are given the same reference numerals. In addition, in the following description of the embodiments, it may be omitted to duplicate the same or corresponding components. However, even if the description of the component is omitted, it is not intended that such component is not included in any embodiment.

1 is a perspective view illustrating a suspension arm 1 according to an embodiment of the present disclosure, and FIG. 2 is a perspective view illustrating the suspension arm 1 according to an embodiment of the present disclosure in a direction different from that of FIG. 1.

The suspension arm 1 according to an embodiment of the present disclosure may be used as an upper control arm of a wishbone suspension. In addition, although not shown in the figures of the present disclosure, the suspension arm 1 may also be applied to the lower control arm in the same manner as the upper control arm.

The suspension arm 1 according to one embodiment may be composed of two or more kinds of materials as the composite suspension arm. The composite suspension arm may be defined as a hybrid suspension arm that can reduce weight and maintain the same or similar rigidity as the suspension arm made of metal, compared to the suspension arm made of metal. For example, the suspension arm 1 may mean a suspension arm or a suspension arm in which an insert molding part 20 made of plastic is formed in the arm body 10 of steel to achieve light weight of the vehicle. Can be. In addition, the suspension arm 1 is further provided with a steel reinforcement (not shown) inside the arm body 10 in order to improve the mechanical strength to strengthen the strength of the suspension arm (1) and the arm body 10 and The bondability of the insert molding part 20 may be enhanced.

Suspension arm 1 may include arm body 10, insert molding 20, bush assembly 100, and ball joint 30. The arm body 10 may be made of steel material. The insert molding part 20 may be configured such that the plastic material is insert injection molded to be coupled to the arm body 10. The ball joint 30 may be fixed to one side of the arm body 10 during the insert injection process of the insert molding part 20. The bush assembly 100 may constitute part of the suspension arm 1.

The arm body 10 forms a skeleton of the suspension arm 1 and may be manufactured by pressing a metal plate (for example, high tensile steel plate made of steel). When the suspension arm 1 is used as the upper control arm, the arm body 10 may have a Y-shaped plane shape. In this case, the arm body 10 may include first and

second leg portions

12, 13. When the suspension arm 1 is used as a lower control arm, the arm body may have an L-shaped plane shape.

Referring to FIG. 1, button portions 225 and 235 (coupling flanges) may be formed on upper walls of the first and

second leg portions

12 and 13, respectively. The

button parts

225 and 235 may be formed through a portion of the insert molding part 20 passing through holes formed in the upper walls of the first and

second leg parts

12 and 13 in the insert injection process. The

button parts

225 and 235 may reinforce the coupling property between the insert molding part 20 and the arm body 10 to prevent the insert molding part 20 and the arm body 10 from being spaced apart from each other.

The button part 225 formed in the first leg part 12 may be provided as a plurality of

button parts

2251, 2252, 2253, and 2254. The button portion 235 formed on the second leg portion 13 may be provided as a plurality of

button portions

2351, 2352, 2353, and 2354. In addition, the

button portions

2253 and 2353 pass through the boss portion (not shown) of the mold so that the position of the arm body 10 is fixed in the mold (not shown), so that the hole is not completely filled with the molding material. This can be formed.

The plastic molding material may be injected through the nozzle (not shown) to the injection part 35 constituting the two

button parts

2252 and 2352 and the ball joint 30. That is, the insert molding material may be injected into the arm body 10 at a total of three points.

3 is an exploded perspective view showing an exploded configuration of the suspension arm 1 shown in FIGS. 1 and 2.

The arm body 10 may include a joint part 11 and first and

second leg parts

12 and 13 extending to both sides from the joint part 11. A coupling ring 11a constituting a part of the ball joint 30 may be fixed to the front end of the joint part 11. The coupling ring 11a may be welded to the tip of the joint portion 11 to be coupled. A large diameter hole 11b through which a suspension shaft (not shown) penetrates may be formed in the central portion of the joint part 11.

The first leg part 12 may have an upper wall 12a and two sidewalls 12b extending vertically from both ends of the upper wall 12a. The second leg portion 13 may have two sidewalls 13b extending vertically from both ends of the upper wall 13a and the upper wall 13a. Accordingly, the first and

second leg portions

12 and 13 may have a cross section of a 'c' shape. At least one small diameter hole may be formed in the

upper walls

12a and 13a of the first and

second leg portions

12 and 13 to perform insert injection and to form a button portion.

The bush pipe 110 may be fixed to the

tip portions

12c and 13c of the first and

second leg portions

12 and 13. The bush pipe 110 may be welded to and coupled to the

tip portions

12c and 13c of the first and

second leg portions

12 and 13. The

tip portions

12c and 13c may have a tip surface corresponding to a portion of the cylindrical surface to surround the outer circumferential surface of the bush pipe 110. In addition, the bush pipe 110 may constitute an outer pipe of the bush assembly 100.

The insert molding part 20 is a joint molding part 210 coupled to the first and second

leg molding parts

220 and 230 and the joint part 11 coupled to the first and

second leg parts

12 and 13, respectively. ) May be included. A ball joint coupling part 250 constituting a part of the ball joint 30 may be formed at the front end of the joint molding part 210.

Bush molding parts

223 and 233 may be formed at the front ends of the first and second

leg molding parts

220 and 230 to surround the front ends of the bush pipes 110. The grating ribs 240 may be formed in the insert molding part 20 to improve strength.

The bush assembly 100 may include a bush pipe 110 and a bush bearing assembly 101. The bush bearing assembly 101 may be integrally fixed to the bush pipe 110 through insert injection. Detailed description thereof may be described later.

4 is a cross-sectional view showing a configuration in which the suspension arm 1 shown in FIG. 2 is cut in the I-I direction, and FIG. 5 is an exploded perspective view showing an exploded configuration of the ball joint 30 shown in FIG.

The ball joint 30 may include a ball stud 310, a bearing 320, a coupling ring 11a, and a ball joint coupling 250. The ball stud 310 may include a spherical ball 311 and a rod-shaped rod 312. The ball 311 may be accommodated in the bearing 320 to be configured to rotate relative to the bearing 320. The rod 312 may extend upward from the top of the ball 311 and be integrally formed with the ball 311. The upper end of the rod 312 may be coupled to a knuckle (not shown) of the vehicle. As the vehicle travels, the rod 312 may be configured to pivot about the bearing 320 about the ball 311.

The bearing 320 may be configured to receive at least a portion of the ball 311 of the ball stud 310. The inner circumferential surface 320a of the bearing 320 may be formed in a partial spherical shape to be in contact with the ball 311 of the ball stud 310. For example, the center point of the inner circumferential surface 320a of the bearing 320 may be disposed to coincide with the center point of the ball 311 of the ball stud 310. The upper end of the bearing 320 may be formed lower than the upper end of the ball 311 of the ball stud 310. Thus, the ball 311 can be easily accommodated in the bearing 320. The upper end of the ball 311 that is not accommodated in the bearing 320 may be covered by the ball joint coupling 250.

The bearing 320 may be manufactured by injection molding a nylon-based plastic material. For example, it may be made of a mixed material of polyamide and glass fiber, such as PA6-GF50. Therefore, the mechanical strength of the bearing 320 can be secured sufficiently. That is, the bearing 320 may be understood as a ball seat on which the ball 311 of the ball stud 310 is seated.

The ball joint coupling part 250 may constitute a housing of the ball joint 30. In the injection molding of the insert molding part 20, the ball joint coupling part 250 may be injected between the coupling ring 11a and the bearing 320 to form a housing, and may be formed to surround the side wall part 11c. . Therefore, the coupling ring 11a and the side wall portion 11c may have a structure in which they are not directly coupled. In addition, the ball joint 30 may have a structure that is integrally fixed to the suspension arm.

The ball joint 30 may further include a dust cover 330. The dust cover 330 may have an upper end mounted on the rod 312 of the ball stud 310 and a lower end coupled to the outer circumferential part 250a of the ball joint coupling part 250. The lower end of the dust cover 330 may be fixed to the outer circumferential portion 250a of the coupling portion 250 by the ring clip 340. The dust cover 330 may prevent foreign substances such as water or dust from penetrating into the bearing 320 or the ball joint coupling part 250.

FIG. 6 is a cross-sectional view illustrating a structure in which the suspension arm 1 shown in FIG. 2 is cut in the II-II direction, and FIG. 7 is an exploded perspective view illustrating an exploded configuration of the bush assembly 100 illustrated in FIG. 6. .

The bush assembly 100 may include a bush pipe 110, a bush bearing 115, an insert member 140, and an inner pipe 150. The bush pipe 110 may be fixed to one side of the arm body 10 shown in FIG. 3. The bush bearing 115 may be disposed coaxially with the axial direction R of the bush pipe 110 and may have a convex shape in the outer radial direction D ₁ such that the cross-sectional diameter of the central portion is larger than the cross-sectional diameter of both ends. have. The insert member 140 is filled between the inner circumferential surface 111 of the bush pipe 110 and the outer circumferential surface 115a of the bush bearing 115 to fix the position of the bush bearing 115 inside the bush pipe 110. Can be. The inner pipe 150 may be rotatably coupled to the bush bearing 115.

The bush pipe 110 may be applied as an outer pipe surrounding the outer circumference of the inner pipe 150. The inner circumferential surface 111 of the bush pipe 110 may have a concave-convex shape in which the protruding portion 111a and the concave portion 111b are repeated in the form of a step. Correspondingly, the outer circumferential surface 141 of the insert member 140 may have a concave-convex shape in which the concave portion 141a and the protruding portion 141b are repeated in a step like shape. Accordingly, since the inner circumferential surface 111 of the bush pipe 110 and the outer circumferential surface 141 of the insert member 140 are radially inserted into each other, the bush pipe 110 has an axial direction of the insert member 140. (R) Can block movement.

The bush bearing 115 may include a first bush bearing 120 fitted at one side of the inner pipe 150 and a second bush bearing fitted at the other side of the inner pipe 150 and coupled to the first bush bearing 120. 130). The bush bearing 115 may have a mirror symmetrical shape with respect to the cross-sectional center line M of the bush assembly 100. First and

second labyrinth structures

160 and 170 may be formed between both ends of the bush bearing 115 and each of both ends of the inner pipe 150.

The bush bearing 115 can be manufactured by insert injection molding a material comprising PA6-GF50. In other embodiments, an engineering plastic (eg, polyacetal (POM)) material may be used as the material for constructing the bush bearing 115. The PA6-GF50 material has better resistance to injection pressure than POM even though its wear performance is lower than that of POM. Therefore, when PA6-GF50 is used as the material of the bush bearing 115, even if the insert member 140 is injected, resistance to injection pressure can be secured.

The insert member 140 may be formed by insert injection of a thermoplastic polyurethane (TPU) material. In a method of injecting rubber into a separate steel pipe, the bush bearing may melt due to high pressure and heat. On the contrary, since the insert member 140 according to the embodiments of the present disclosure uses a TPU material that can be injected at a relatively low temperature and low pressure as compared to rubber, the bush pipe may not be melted and maintain its shape.

The first bush bearing 120 has a first sealing portion 121 forming a non-contact sealing structure with the inner pipe 150, a first contact portion 122 whose cross-sectional diameter gradually increases from the first sealing portion 121, It may include a first central portion 123 extending in the axial direction (R) from the first contact portion (122). The second bush bearing 130 has a second sealing part 131 and a second forming a non-contact sealing structure with the inner pipe 150 on the opposite side of the first sealing part 121 based on the cross-sectional center line M. It may include a second contact portion 132 gradually increasing in cross-sectional diameter from the sealing portion 131, and a second center portion 133 extending from the second contact portion 132 in contact with the first central portion 133. . Through such a structure, the bush bearing 115 may have a shape in which the central portion is convex in the outer radial direction D ₁ .

The inner pipe 150 may include first and

second protrusions

152 and 153 that are mirror symmetrically formed at both sides with respect to the cross-sectional center line M. Referring to FIG. The first protrusion 152 may be configured to protrude in the outer radial direction D ₁ to be in line contact with the inner circumferential surface of the first contact portion 122 of the first bush bearing 120. The second protrusion 153 may be configured to protrude in the outer radial direction D ₁ to be in linear contact with the inner circumferential surface of the second contact portion 132 of the second bush bearing 130. A lubricant (eg, grease) may be filled in the space between the inner circumferential surfaces of the first and second

central portions

123 and 133 and the outer circumferential surfaces of the first and

second protrusions

152 and 153.

8 is an enlarged view illustrating an enlarged portion of the first bush bearing 120 in FIG. 6, and FIG. 9 is an enlarged view illustrating an enlarged portion of the second bush bearing 130 in FIG. 6.

The first and

second bush bearings

120 and 130 may be coupled to each other by a snap method. The first bush bearing 120 may include a coupling portion 127 extending in the axial direction R from the outer circumferential surface of the first central portion 123 toward the second central portion and having the coupling protrusion 128 formed on the inner circumferential surface. In addition, an outer circumferential surface of the second central portion 133 of the second bush bearing 130 may have a coupling groove 137 configured to insert the coupling protrusion. The engaging protrusion 128 may be formed to protrude in the inner radial direction D ₂ . The coupling groove 137 may be formed to correspond to the recess in the inner radial direction D ₂ .

In the process of assembling the first and

second bush bearings

120 and 130, the first bush bearing 120 is configured to move in the axial direction D ₃ , and the second bush bearing 130 is axially inward ( D ₄ ). First, the coupling portion 127 may be opened in the outer radial direction D ₁ by the coupling protrusion 128 while being in contact with the second central portion 133. The tip surface 128a facing the inner side D ₃ of the coupling protrusion 128 may be formed of an inclined surface, so that the coupling portion 127 may be well opened. Thereafter, after the coupling protrusion 128 is inserted into the coupling groove 137, the position of the axial direction R of the second bush bearing 130 with respect to the first bush bearing 120 may be fixed.

Referring to FIG. 8, the first circle C1 may represent a trajectory of a circle extending from a portion of an outer circumferential surface of the first protrusion 152. The second circle C2 may represent the trajectory of the circle extending from a portion of the inner circumferential surface of the first contact portion 122. The radius of curvature R ₁ of the first circle C1 may be configured to be smaller than the radius of curvature R ₂ of the second circle C2. Referring to FIG. 9, the third circle C3 may represent a trajectory of a circle extending from a portion of an outer circumferential surface of the second protrusion 153. The fourth circle C4 may represent the trajectory of the circle extending from a portion of the inner circumferential surface of the second contact portion 132. The radius of curvature R ₃ of the third circle C3 may be configured to be smaller than the radius of curvature R ₄ of the fourth circle C4.

8 and 9, the right part and the left part of the bush assembly 100 may have a symmetrical shape with respect to the center line M shown in FIG. 6. Therefore, the radius of curvature R ₁ and the radius of curvature R ₃ may have the same size. In addition, the radius of curvature R ₂ and the radius of curvature R ₄ may have the same size.

The radius of curvature R ₁ , R ₃ of the outer circumferential surfaces of the first and

second protrusions

152, 153 is smaller than the radius of curvature R ₂ , R ₄ of the inner circumferential surfaces of the first and

second contact portions

122, 132. As such, the outer circumferential surfaces of the first and

second protrusions

152 and 153 and the inner circumferential surfaces of the first and

second contact portions

122 and 132 may be configured to be in line contact with each other. Accordingly, the sliding torque between the first and

second bush bearings

120 and 130 and the inner pipe 150 can be significantly reduced compared to the surface contact method.

Referring to FIG. 8, the first inner circumferential region 124 of the first bush bearing 120 may include a plurality of

first protrusions

1241 and 1242 protruding in an inner radial direction. In addition, a plurality of

first grooves

151a and 151b may be formed in the first outer circumferential region 151 of the inner pipe 150 to correspond to the shapes of the plurality of

first protrusions

1241 and 1242. Referring to FIG. 9, the second inner circumferential region 134 of the second bush bearing 130 may include a plurality of

second protrusions

1341 and 1342 protruding in the inner radial direction D ₂ . In addition, a plurality of

second grooves

154a and 154b may be formed in the second outer circumferential region 154 of the inner pipe 150 to correspond to the shapes of the plurality of

second protrusions

1341 and 1342. In the embodiments of the present disclosure, the number of the first and second grooves is provided as two, but is not limited thereto, and may be provided as one or three or more according to the specification of the bush assembly.

The first labyrinth structure 160 may be formed in a tortuous maze path between the

first protrusions

1241 and 1242 and the

first grooves

151a and 151b. The second labyrinth structure 170 may be formed in a tortuous maze path between the

second protrusions

1341 and 1342 and the

second grooves

154a and 154b. Each meandering maze path can be filled with a lubricant (eg grease) to ensure sealing.

The first inner circumferential region 151 may be formed at the axially outer side D ₄ end side of the inner pipe 150, and the second inner circumferential region 154 is the axial inner side D ₃ of the inner pipe 150. It may be formed at the end side. Thus, even without a separate sealing device, it is possible to completely seal between the bush bearing and the inner pipe. In addition, the process is simplified compared to the method using a separate sealing device, it is possible to reduce the manufacturing cost of the bush assembly.

Hereinafter, a method of manufacturing the suspension arm 1 according to an embodiment of the present disclosure will be described. For example, the manufacturing method of the suspension arm 1 may proceed in the order according to FIGS. 10 to 15.

10 is a perspective view illustrating an assembly process of the bush bearing 115 and the inner pipe 150 and an assembly process of the ball stud 310 and the bearing 320 according to an exemplary embodiment of the present disclosure. That is, FIG. 10 illustrates an assembly process of the bush bearing assembly 101 and the bearing assembly 315.

Referring to FIG. 10A, first, the first bush bearing 120, the inner pipe 150, and the second bush bearing 130 are disposed in the axial direction R. Referring to FIG. Next, the first and

second bush bearings

120 and 130 are moved toward the center line M of the inner pipe 150. Accordingly, the first and

second bush bearings

120 and 130 are coupled, and the assembly of the bush bearing assembly 101 is completed. In the assembled state, the inner pipe 150 has a structure that does not separate from the first and

second bush bearings

120 and 130.

Referring to FIG. 10B, first, the bearing 320 and the ball stud 310 are arranged such that the inlet of the bearing 320 faces the ball 311 of the ball stud 310. Next, lubricant is injected into the bearing 320, and the ball 311 is inserted into the bearing 320. In this process, the inlet of the bearing 320 may be slightly open. Thus, the assembly of the bearing assembly 315 is completed.

FIG. 11 is a perspective view illustrating a process of installing the bush bearing assembly 101 and the bearing assembly 315 to the arm body shown in FIG. 3.

Referring to FIG. 11A, first, the arm body 10 is aligned in the direction for injection. For example, the

top walls

12a and 13a of the first and

second leg portions

12 and 13 may be aligned in the upward direction. In addition, the axial direction R of the bush pipe 110 may be arranged in a direction perpendicular to the direction in which the

upper walls

12a and 13a face. Next, the bearing assembly 315 may be arranged in a direction toward the opening of the coupling ring 11a in which the bearing 320 is fixed to the arm body 10. In addition, the bush bearing assembly 101 may be arranged such that the axial direction of the bush bearing assembly 101 and the axial direction R of the bush pipe 110 coincide with each other.

Referring to FIG. 11B, the bearing 320 portion of the bearing assembly 315 is inserted into the coupling ring 11a. In this state, the center of the coupling ring 11a and the center of the bearing 320 may be arranged side by side, and the inner circumferential surface of the coupling ring 11a and the outer circumferential surface of the bearing 320 are arranged not to contact each other. It is also possible to insert the bush bearing assembly 101 into the bush pipe 110. In this state, the outer circumferential surface of the bush bearing assembly 101 and the inner circumferential surface of the bush pipe 110 are arranged not to contact. For example, the cross-sectional center line of the bush pipe 110 and the cross-sectional center line of the bush bearing assembly 101 may be arranged to coincide. In this process, the arm body assembly 10a which is in a state before insert injection may be manufactured.

12 is a perspective view illustrating a process of forming an insert molding part 20 by insert injection molding into the arm body assembly 10a of FIG. 11.

Referring to FIG. 12A, a plurality of holes for insert injection may be provided in the arm body 10. A plurality of holes 121a may be formed in the upper wall 12a of the first leg part 12, and a plurality of holes 131a may be formed in the upper wall 13a of the second leg part 13. have. The plurality of holes 121a may be provided as four

holes

1211, 1212, 1213, and 1214. In addition, the plurality of holes 131a may be provided as four

holes

1311, 1312, 1313, and 1314.

The injection position I may include a first position I1 corresponding to the hole 1212 of the first leg part 12, a second position I2 corresponding to the hole 1312 of the second leg part 13, And a third position I3 corresponding to the ball joint 30. As such, since the insert molding part is injected at three points, the injection molding may spread to minimize the generation of the welding line over the entire area of the arm body 10. As a material for insert injection, for example, PA6-GF50 can be used.

Referring to FIG. 12B, after the insert injection is completed, the insert molding part 20 may be coupled to the arm body 10. In addition, a button portion 225 may be formed in the first leg portion 12, and a button portion 235 may be formed in the second leg portion 13. In the process of inserting the insert molding part 20, the ball joint coupling part 250 may be formed. The ball joint coupling portion 250 may be injected between the bearing assembly 315 and the coupling ring 11a to constitute a housing.

FIG. 13 is a perspective view illustrating a process of forming an insert member by insert injection molding into the assembly 10b of the arm body and the insert molding unit illustrated in FIG. 12.

Referring to FIG. 13A, the inner circumferential surface of the bush pipe 110 and the outer circumferential surface of the bush bearing assembly 101 are spaced apart without contacting each other. Referring to FIG. 13B, the insert member 140 may be formed by inserting the TPU material into a space between the inner circumferential surface of the bush pipe 110 and the outer circumferential surface of the bush bearing assembly 101.

The injection position I4 of the insert member 140 may include three points spaced apart from each other. The three points may be evenly spaced apart from one another, and for example arranged to form an equilateral triangle shape. Since the insert member 140 is formed by injecting at three points in this way, it may have an appropriate injection pressure, and the injection may be uniformly distributed.

FIG. 14 is a perspective view illustrating a process of insert injection two times in a state where the arm body assembly 10a illustrated in FIG. 11 is inserted into a mold.

Referring to FIG. 14A, the arm body assembly 10a may be inserted into a suspension arm shaped groove 1100 formed in the mold 1000. In this state, the upper wall of the arm body may be disposed to face the upper side of the mold. Next, referring to FIG. 14B, a first material including PA6-GF50 is insert-injected through the first nozzle N1 to three injection positions I1, I2, and I3 to form an insert molding part. Can be. Next, referring to FIG. 14C, in a state in which the arm body assembly 10a is not separated from the mold 1000, the second material including the TPU opens the bush pipe through the first nozzle N2. The insert member may be inserted into the insert member. Referring to FIG. 14D, the suspension arm 1 having completed injection of the insert molding part and injection of the insert member may be taken out from the mold 1000.

Referring to (b) and (c) of FIG. 14, the insert injection of the first material and the insert injection of the second material may be performed in one mold 1000. The time interval between the process of insert injection of the first material and the insert injection of the second material may not be substantially large. For example, insert injection of the first material may be terminated and insert injection of the second material may proceed immediately. Therefore, the manufacturing process can be simplified and the work efficiency can be improved.

Although process steps, method steps, algorithms, and the like have been described in sequential order in the flowcharts shown in FIGS. 15 and 16, such processes, methods, and algorithms may be configured to be performed in any suitable order. In other words, the steps of the processes, methods, and algorithms described in various embodiments of the present disclosure need not be performed in the order described in this disclosure. In addition, although some steps are described as being performed asynchronously, in some embodiments these some steps may be performed simultaneously. Moreover, illustration of the process by depiction in the figures does not mean that the illustrated process excludes other changes and modifications thereto, and any of the illustrated process or steps thereof is one of the various embodiments of the present disclosure. It is not meant to be essential to more than one, nor does it mean that the illustrated process is preferred.

15 is a flowchart illustrating a method (S1200) of manufacturing a suspension arm according to an embodiment of the present disclosure.

The method (S1200) of manufacturing a suspension arm includes manufacturing a female body including a joint part having a coupling ring in which a ball joint is installed at a tip end, and a leg part extending from the joint part and having a bush pipe fixed at the tip end and an injection hole formed therein. (S1210); Inserting the arm body into the mold such that the ball joint is disposed in the coupling ring and the assembly of the bush bearing and the inner pipe is coaxially disposed with the bush pipe (S1220); Injecting the first material toward the coupling ring through the injection hole in a direction perpendicular to the leg part to form an insert molding part (S1230); Injecting the second material between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing to form an insert member (S1240).

16 is a flowchart illustrating a step S1220 of inserting an arm body into a mold in the method of manufacturing a suspension arm according to an embodiment of the present disclosure.

Inserting the female body into the mold (S1220), the step of inserting the female body into the mold so that the upper surface of the leg portion to the injection position (S1221); Placing in the coupling ring such that the bush bearing of the ball joint faces the injection position (S1222); And disposing an assembly of the bush bearing and the inner pipe in the bush pipe so as to be coaxially disposed with the bush pipe (S1223).

While the technical spirit of the present disclosure has been described with reference to some embodiments and the examples shown in the accompanying drawings, the technical spirit and scope of the present disclosure may be understood by those skilled in the art. It will be appreciated that various substitutions, modifications, and alterations can be made in the scope. Also, such substitutions, modifications and variations may be considered to be within the scope of the appended claims.

Claims

In the bush assembly installed on the suspension arm,

An outer pipe fixed to one side of the suspension arm;

A bush bearing disposed coaxially with the axial direction of the outer pipe and having a convex shape in the outer radial direction such that the cross-sectional diameter of the central portion is larger than the cross-sectional diameter of both ends;

An insert member filled between an inner circumferential surface of the outer pipe and an outer circumferential surface of the bush bearing to fix the bush bearing inside the outer pipe; And

And an inner pipe rotatably coupled to the bush bearing.
The method of claim 1,

And wherein the insert member is formed by insert injection of thermoplastic polyurethane (TPU) material between the inner circumferential surface of the outer pipe and the outer circumferential surface of the bush bearing.
The method of claim 1,

The bush bearing,

A first bush bearing fitted at one side of the inner pipe; And

And a second bush bearing fitted at the other side of the inner pipe and coupled to the first bush bearing.
The method of claim 3,

The inner pipe has a bush assembly having a first protrusion configured to radially protrude in line contact with the inner circumferential surface of the first bush bearing and a second protrusion configured to radially protrude in line with the inner circumferential surface of the second bush bearing .
The method of claim 4, wherein

The first bush bearing,

A first seal forming a non-contact sealing structure with the inner pipe;

A first contact portion configured to gradually increase in cross-sectional diameter from the first seal portion and to make linear contact with the first protrusion of the inner pipe;

A first central portion extending from the first contact portion,

The second bush bearing,

A second seal forming a non-contact sealing structure with the inner pipe on the opposite side of the first seal with respect to the cross-sectional center line of the inner pipe;

A second contact portion configured to gradually increase in cross-sectional diameter from the second seal portion and to make linear contact with the second protrusion of the inner pipe;

And a second center portion extending from the second contact portion to be in contact with the first center portion.
The method of claim 5,

A first inner circumferential region of the first bush bearing and a first outer circumferential region of the inner pipe form a first labyrinth structure,

And a second inner circumferential region of the second bush bearing and a second outer circumferential region of the inner pipe form a second labyrinth structure.
The method of claim 6,

The first inner circumferential region of the first bush bearing includes a plurality of first protrusions protruding in an inner radial direction, and the first outer circumferential region of the inner pipe corresponds to a shape of the plurality of first protrusions. Grooves are formed,

The second inner circumferential region of the second bush bearing includes a plurality of second protrusions protruding in the inner radial direction, and the second outer circumferential region of the inner pipe corresponds to the shape of the plurality of second protrusions. A bush assembly in which a groove is formed.
The method of claim 5,

A bush assembly is filled with a lubricant in the space space formed by the first and second protrusions and the first and second central portions.
The method of claim 5,

The first bush bearing includes a coupling portion extending in an axial direction from the outer circumferential surface of the first central portion toward the second central portion and having a coupling protrusion formed on the inner circumferential surface.

Bushing assembly, the outer peripheral surface of the second bush bearing is formed with a coupling groove configured to insert the coupling projection.
The method of claim 5,

The radius of curvature of the outer circumferential surface of the first protrusion is configured to be smaller than the radius of curvature of the inner circumferential surface of the first contact portion in contact with the first protrusion,

And the radius of curvature of the outer circumferential surface of the second protrusion is smaller than the radius of curvature of the inner circumferential surface of the second contact portion in contact with the second protrusion.
Arm body composed of metal material;

An insert molding part in which a first material is inserted into the arm body by insert injection;

A ball joint fixed to one side of the arm body by the insert injection; And

A bush assembly installed on the other side of the arm body,

The bush assembly,

A bush pipe fixed to one side of the arm body;

A bush bearing disposed coaxially with the axial direction of the bush pipe and having a convex shape in the outer radial direction such that the cross-sectional diameter of the central portion is larger than the cross-sectional diameter of both ends;

An insert member configured to fill a second material between an inner circumferential surface of the bush pipe and an outer circumferential surface of the bush bearing to fix the bush bearing inside the bush pipe; And

And an inner pipe rotatably coupled to the bush bearing.
The method of claim 11,

The female body,

A joint part having a coupling ring at which a ball joint is installed at a front end thereof; And

And a leg portion formed from an injection hole extending from the joint portion and fixed to the tip of the bush pipe and insert injection of the first material.
The method of claim 12,

The leg portion includes first and second leg portions extending to both sides from the arm body,

The insert molding portion is perpendicular to the first and second leg portions toward three points including the injection hole in which the first material is formed in the first leg portion, the injection hole formed in the second leg portion, and the coupling ring. Suspension arm formed by injection in one direction.
The method of claim 11,

The insert member is formed by injecting the second material in a direction parallel to the axial direction of the bush pipe.
The method of claim 11,

The first material consists of a PA6-GF50 material,

The second material consists of a thermoplastic polyurethane (TPU) material.
Manufacturing an arm body including a joint part having a coupling ring installed at a tip end thereof, and a leg part extending from the joint part and having a bush pipe fixed at the tip end and having injection holes formed therein;

Inserting the arm body into a mold such that a ball joint is disposed in the coupling ring and an assembly of bush bearing and inner pipe is coaxially disposed with the bush pipe;

Injecting a first material toward the injection hole and the coupling ring in a direction perpendicular to the leg portion to form an insert molding portion; And

Injecting a second material between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing to form an insert member.
The method of claim 16,

Inserting the female body into the mold,

Inserting the arm body into the mold such that an upper surface of the leg portion faces an injection position;

Placing the ball joint in the engagement ring such that the bearing of the ball joint faces the ejection position; And

Disposing the assembly of the bush bearing and the inner pipe inside the bush pipe such that the bush bearing and the inner pipe are disposed coaxially with the bush pipe.
The method of claim 16,

And the second material is injected at three spaced apart points between the inner circumferential surface of the bush pipe and the outer circumferential surface of the bush bearing.