Patent ID: 12188515

DESCRIPTION OF REFERENCE NUMERALS

1: suspension arm10: suspension arm body20: molding part30: ball joint31: ball stud32: bearing33: arm body36: insert molding part40: bush100,200,300: housing110,210,310: matching portion111,211,311: matching surface

DETAILED DESCRIPTION

Embodiments of the present disclosure are exemplified for the purpose of describing the technical spirit of the present disclosure. The scope of the claims according to the present disclosure is not limited to the embodiments described below or to the detailed descriptions of these embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning commonly understood by those skilled in the art to which the present disclosure pertains. All terms used herein are selected for the purpose of more clearly describing the present disclosure and not limiting the scope of the present disclosure defined by appended claims.

Unless the phrase or sentence clearly indicates otherwise, the terms “comprising”, “including”, “having” and the like used herein should be construed as open-ended terms encompassing the possibility of including other embodiments.

The singular form described herein may include the plural form unless the context clearly dictates otherwise, and this is equally applied to the singular form set forth in the claims.

Throughout the present disclosure, when a component is referred to as being “connected” or “coupled” to another component, the component may be directly connected or coupled to another component, or may be connected or coupled to another component by intervening yet another component therebetween.

Dimensions and numerical values described in the present disclosure are not limited only to the dimensions and numerical values described herein. Unless otherwise specified, these dimensions and numerical values may be understood to mean the values described herein and the equivalent ranges including the described values. For example, a dimension of “2 mm” described herein may be understood to include “about 2 mm.”

Directional directives of “upward”, “above” and the like used herein are described on the basis of a direction in which a rod of a ball stud is positioned relative to a ball in the accompanying drawings, directional directives of “downward”, “below” and the like mean the direction opposite the above “upward”, “above” and the like. The rod and the ball shown in the accompanying drawings may be arranged in directions different from the above directions, and the directional directives may be understood based thereon.

FIG.1is a partial cross-sectional view showing a conventional ball joint.

Referring toFIG.1, a conventional ball joint30′ comprises a ball stud31′ having a ball31a′ and a rod31b′; a bearing32′ in which the ball31a′ is accommodated; and a housing100′ in which the ball31a′ and the bearing32′ are accommodated. An insert molding part36′ is formed to couple the bearing32′ with the housing100′. The insert molding part36′ also serves to couple the ball joint30′ with the arm body33′ in a state in which the ball joint30′ is mounted on the arm body33′.

In such a conventional configuration, there is a problem that it is difficult to provide a matching surface between the housing100′ and a mold500during the manufacturing process of the suspension arm. In order to form the matching surface, a radial thickness of the housing100′ should be increased, which makes it difficult to reduce the weight of the housing100′.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are assigned to the same or corresponding components. Further, in the following descriptions of the embodiments, duplicate descriptions of the same or corresponding components may be omitted. However, even though a description of a component is omitted, such a component is not intended to be excluded in any embodiment.FIG.2is a perspective view of a vehicular suspension arm1according to one embodiment of the present disclosure, andFIG.3is a perspective view of the vehicular suspension arm1according to one embodiment of the present disclosure when viewed in another direction.

The suspension arm1according to one embodiment of the present disclosure may be used as an upper control arm. Also, although not shown in the drawings of the present disclosure, the suspension arm1according to the present disclosure may be used as a lower control arm similarly to the upper control arm.

The suspension arm1according to one embodiment may be formed as a composite suspension arm, which is formed of two or more types of materials. The composite suspension arm may be defined as a hybrid suspension arm which has a reduced weight compared to a suspension arm made of a metal material and stiffness equal to or similar to that of the suspension arm made of a metal material. For example, the suspension arm1means a suspension arm in which a molding part20made of a plastic material is formed on a suspension arm body10made of a steel material in order to reduce the weight of the vehicle. In addition, in the suspension arm1, a reinforcing part (not shown) made of a steel material may be further provided in the suspension arm body10in order to improve the mechanical strength of the suspension arm1. Accordingly, the strength of the suspension arm1may be enhanced and the coupling of the suspension arm body10and a molding part20may be enhanced.

The vehicular suspension arm1may include the suspension arm body10, the molding part20, a ball joint30, and bushes40.

The suspension arm body10may be manufactured by applying a general press process to a vehicular high-tension steel plate. The suspension arm body10may be formed of a metal material. A surface of the suspension arm body10may be coated for corrosion protection. The suspension arm body10may form the skeleton of the suspension arm1and may be manufactured by press-forming a metallic plate (for example, a high-tension steel plate). When the suspension arm1is used as the upper control arm, the suspension arm body10may have a Y-like planar shape, but not necessarily limited thereto.

The suspension arm body10may comprise two leg parts12and a joint part11integrally connecting the two leg parts12. A bush pipe13may be coupled to a leading end portion of each of the two leg parts12. A ball joint pipe14may be coupled to a leading end portion of the joint part11. The bush40may be inserted into each of the two bush pipes13.

In one embodiment, the bush pipes13and the ball joint pipe may be respectively coupled to the leading end portions of the leg parts12and the leading end portion of the joint part11by welding. For example, the welding process may be performed by an electric welding, a CO2welding, an oxygen welding, an argon welding, a spot welding or the like, but not limited thereto. In another embodiment, the bush pipes13and the ball joint pipe14may be respectively coupled to the leading end portions of the leg parts12and the leading end portion of the joint part11in a manner other than the above-described welding, for example, a laser welding, an ultra sonic or the like, but not limited to these methods.

FIG.4is an assembly view showing an assembling structure of the suspension arm1according to one embodiment of the present disclosure.

Referring toFIG.4, the molding part20is coupled to one surface of the suspension arm body10. The bush40is inserted into the bush pipe13located at the leading end portion of each of the leg parts12. The ball joint30is inserted into the ball joint pipe14located at the leading end portion of the joint part11of the suspension arm body10.

In one embodiment, the molding part20is formed of a fiber-reinforced plastic material. Specifically, the molding part20may be formed of a polyamide resin such as nylon 6 (PA6), nylon 66 (PA66), or the like, or may be formed of a polyamide resin in which a glass fiber is included in nylon 6, nylon 66, or the like. The molding part20may be generally similar in shape to the suspension arm body10. That is, the molding part20may comprise two leg parts22and a joint part21. The molding part20may be insert-injected into the mold500to be coupled to the suspension arm body10.

In one embodiment, the molding part20may comprise reinforcing rib having a generally lattice pattern shape and formed to protrude integrally from the molding part20. The shape of the reinforcing rib may be designed using a computer-aided optimum design program to minimize the weight of the molding part20.

A housing100is inserted into the ball joint pipe14. A coupled body of a bearing32and a ball stud31are inserted into the housing100. A dust cover34is covered on the upper side of the housing100. In the lower side of the housing100, a molding material is injected to form an insert molding part36.

FIG.5is an enlarged view of an area A inFIG.2.FIG.6is a cross-sectional view of a portion of the ball joint30of the vehicular suspension arm1according to one embodiment of the present disclosure.

The ball joint30may comprise the ball stud31including a vertically-extending rod31band a spherical ball31a; the bearing32in which the spherical ball31aof the ball stud31is accommodated and configured to rotatably support the spherical ball31a; the housing100having an inner peripheral portion in which the bearing32is accommodated and an outer peripheral portion; the arm body33coupled to an outer peripheral surface of the housing100; the dust cover34configured to cover a portion of the rod31bof the ball stud31to prevent inflow of external foreign substances; a ring clip35for assembling the dust cover34to the ball stud31; and a protector provided to cover the ball stud31in a direction opposite to the bearing32.

An upper end portion of the rod31bis coupled to a knuckle of the vehicle. As the vehicle travels, the rod31bis configured to be pivotable relative to the bearing32around the ball31a.

The housing100may have a hollow cylindrical shape. For example, the housing100may be manufactured by press-forming a pipe material, or may be manufactured by a forging process.

The bearing32may be manufactured by injection-molding an acetal-based plastic material. For example, the acetal-based plastic material may be POM (Polyacetal, Polyoxymethylene) material. Accordingly, the bearing32can have excellent friction resistance and abrasion resistance, and thus can maintain initial performance even if it is used for a long time. The bearing32may also be defined as a ball seat on which the ball31aof the ball stud31is seated.

The cross section of the arm body33may be formed in a u-like shape. The arm body33may comprise a first extended portion33acoupled to the outer peripheral portion of the housing100, a second extended portion33bextending to be bent in a radially outward direction OR from a lower end of the first extended portion33a, and a third extended portion33cextending to be bent upwardly in an axial direction AD from the second extended portion33b. The arm body33may be formed of a steel material.

FIG.7is a partial rear view of a configuration in which the suspension arm body10and the housing100of the ball joint30are omitted fromFIG.5.

The arm body33, not shown inFIG.7, may be coupled to welding surface130formed on the outer peripheral surface of the housing100by welding. For example, the welding may be performed by an arc welding which supplies heat necessary for the welding through an electric arc generated between a welding rod and a welding target portion. In addition, the welding may be performed by an electric welding, a CO2welding, an oxygen welding, an argon welding, a spot welding or the like, but not limited thereto.

In another embodiment, the outer peripheral surface of the housing100and the arm body33may be coupled to each other in another method, such as a laser welding, an ultra sonic, or the like. However, the coupling method is not limited to the above-exemplified methods.

The welding surface130, in which the arm body33and the housing100are welded, may be formed at plural locations on the outer peripheral surface of the housing100, for example, three locations on the outer peripheral surface of the housing100, as shown inFIG.7. That is, a first welding surface130a, a second welding surface130b, and a third welding surface130cmay be formed on the outer peripheral surface of the housing100.

The first welding surface130a, the second welding surface130b, and the third welding surface130cmay be arranged at regular intervals on the outer peripheral surface of the housing100along a circumferential direction CD. As an example, the first welding surface130a, the second welding surface130b, and the third welding surface130cmay be arranged at intervals of 120 degrees along the circumferential direction CD. Further, each of the first welding surface130a, the second welding surface130b, and the third welding surface130cmay have a length of about 10 mm to 15 mm along the circumferential direction CD.

The coupling force between the housing100and the arm body33may be further enhanced by welding. In consideration of the coupling force between the housing100and the arm body33and/or the manufacturing cost of the suspension arm body10, the number of welding surfaces130may be appropriately designed.

FIG.8is a partial cross-sectional view of a portion of the ball joint30of the vehicular suspension arm1according to one embodiment of the present disclosure.

InFIG.8, the dust cover34to be coupled to the upper portion of the housing100and the ring clip35for assembling the dust cover34to the ball stud31are not shown.

Referring toFIG.8, the housing100may comprise a matching portion110having a matching surface111formed to protrude the radially outward direction OR from an upper portion of the outer peripheral portion of the housing100and to be in contact with a lower surface510of the mold500. The matching surface111may extend in a radial direction. The matching portion110having the matching surface111may comprise an inclined surface112formed to be inclined in the radially outward direction OR from the lower portion of the housing100toward the upper portion of the housing100.

In one embodiment, an angle α between the inclined surface112and a central axis of the housing100may be in a range of, for example, 20 degrees to 65 degrees. As an example, the angle α between the inclined surface112and the central axis of the housing100may be 35 degrees. In addition, a radially linear distance d in the radial direction between a radially leading end surface102of an upper end portion101of the housing100and a radially leading end surface113of the matching portion110may be in a range of, for example, 1.5 mm to 3 mm. As an example, the linear distance d in the radial direction between the radially leading end surface102of the upper end portion101of the housing100and the radially leading end surface113of the matching portion110may be 2.3 mm. Further, a radial thickness t of the housing100below the matching portion110may be in a range of, for example, 2 mm to 4 mm. As an example, the radial thickness t of the housing100below the matching portion110may be 3.15 mm.

A groove120may be formed in an inner peripheral surface of the lower end portion of the housing100to be concave in the radially outward direction OR along the circumferential direction CD of the inner peripheral surface. The groove120may be formed at the lower end portion of the housing100by a turning process.

A space of the groove120formed at the lower end portion of the housing100is filled with the insert molding part36. As a result, the coupling force between the insert molding part36and the housing100in the axial direction AD can be enhanced.

In one embodiment, the groove120may have a depth of 1 mm to 3 mm in the radially outward direction OR from the inner peripheral surface of the housing100and a width of 1 mm to 3 mm in the axial direction AD. When the depth and/or the width of the groove120is less than 1 mm, the space of the groove120becomes too narrow. This makes it difficult to sufficiently secure the coupling force between the insert molding part36and the housing100in the axial direction AD. When the depth and/or the width of the groove120exceeds 3 mm, the mechanical strength of the housing100may be decreased.

A dust cover coupling portion103may be formed in the upper portion of the housing100. The dust cover coupling portion103may be formed between the matching surface111and the upper end portion101of the housing100. The dust cover coupling portion103may be formed to be concave radially inward of the housing100. A portion of the dust cover34may be coupled to the dust cover coupling portion103.

The insert molding part36may be coupled to the bearing32, the housing100, and the arm body33by injecting a molding material to the lower portion of the bearing32and the outer peripheral portion of the housing100. The insert molding part36may cover the lower portion of the bearing32and the outer peripheral portion of the housing100. The insert molding part36may be filled into the groove120formed in the housing100, and may be filled into a space surrounded by the first extended portion33a, the second extended portion33band the third extended portion33cof the arm body33.

Accordingly, the bearing32, the housing100, and the arm body33can be coupled to each another by the insert molding part36.

Since the arm body33is directly coupled to the outer peripheral surface of the housing100, the arm body33is supported by the coupling surface with the outer peripheral surface of the housing100, and the force acting in the axial direction AD is not transmitted to the matching portion110.

Further, since the matching portion110comprises the inclined surface112, even in a specific case in which the welding coupling between the housing100and the arm body33are broken, the force acting in the axial direction AD is transmitted obliquely along the inclined surface112. Thus, the housing100is not supported by the arm body33through the matching portion110in the axial direction AD.

In addition, through the matching portion110, it is possible to reduce the weight of the suspension arm1by reducing the radial thickness of the housing100below the matching portion110while forming the matching surface111to be matched with the lower surface510of the mold500.

In addition, since the matching portion110is matched with the lower surface510of the mold500, the molding material may be prevented from flowing into the dust cover coupling portion103by the mold500during the injection process of the molding. This makes it possible to smoothly perform the coupling between the dust cover34and the dust cover coupling portion103.

FIG.9is a partial cross-sectional view of a portion of the ball joint30of the vehicular suspension arm1according to one embodiment of the present disclosure.

InFIG.9, the dust cover34to be coupled to an upper portion of a housing200and the ring clip35for assembling the dust cover34to the ball stud31are not shown.

Referring toFIG.9, the housing200may comprise a matching portion210formed to protrude in the radially outward direction OR from the upper portion of an outer peripheral portion of the housing200. The matching portion210may comprise a curved surface212formed to be curved in the radially outward direction from the lower portion toward the upper portion of the housing200. A radius R of the curved surface212may be in a range of, for example, 2 mm to 4 mm. Description of other configuration that overlap with the above-described embodiments will be omitted.

In the embodiment ofFIG.9, since the arm body33is directly coupled to the outer peripheral surface of the housing200, the arm body33is supported by the coupling surface with the outer peripheral surface of the housing200. Thus, the force acting in the axial direction is not transmitted to the matching portion210.

Further, since the matching portion210comprises the curved surface212, even in a specific case in which the welding coupling between the housing200and the arm body33are broken, the force acting in the axial direction AD is transmitted obliquely along the curved surface212. Thus, the housing200is not supported by the arm body33through the matching portion210in the axial direction AD.

FIG.10is a partial cross-sectional view of a portion of the ball joint30of the vehicular suspension arm1according to one embodiment of the present disclosure.

InFIG.10, the dust cover34to be coupled to an upper portion of a housing300and the ring clip35for assembling the dust cover34to the ball stud31are not shown.

Referring toFIG.10, the housing300may comprise a matching portion310formed to protrude in the radially outward direction OR from an upper portion of an outer peripheral portion of the housing300. The matching portion310may comprise a matching surface311that is matched with the lower surface510of the mold500and a lower surface312that is parallel to the matching surface311. A distance h between the matching surface311and the lower surface312may be in a range of, for example, 1 mm to 2 mm. Description of other configuration that overlap with the above-described embodiments will be omitted.

In the embodiment ofFIG.10, since the inclined surface112or the curved surface212is not formed on the lower portion of the matching portion310, the volume of the matching portion310may be as small as possible, thereby minimizing the volume of the housing300. This makes it possible to reduce the weight of the housing300as much as possible while forming the matching surface311.

In addition, since the arm body33is directly coupled to the outer peripheral surface of the housing300, the arm body33is supported by the coupling surface with the outer peripheral surface of the housing300, and the force acting in the axial direction is not transmitted to the matching portion310.

FIG.11is a flowchart illustrating a method of manufacturing the vehicular suspension arm1according to one embodiment of the present disclosure.

The method of manufacturing the vehicular suspension arm1according to one embodiment of the present disclosure may comprise: a step (S100) of coupling the arm body33to the outer peripheral portion of the housing100,200,300by welding; a step (S200) of accommodating the spherical ball31aof the ball stud31in the bearing32and rotatably fixing the spherical ball31ain the bearing32; a step (S300) of disposing the coupling body of the housing100,200,300and the arm body33in the mold500; a step (S400) of accommodating the bearing32in which the ball stud31is accommodated in the housing100,200,300; and a step (S500) of injecting a plastic molding material to the lower portion of the bearing32and the outer peripheral portion of the housing100,200,300such that the plastic molding material is coupled to the bearing32, the housing100(200,300) and the arm body33.

At this time, the matching portion110,210,310may be formed on the housing100,200,300to protrude in the radially outward direction OR from the outer peripheral surface of the upper portion of the housing100,200,300. In the step (S300) of disposing the coupling body of the housing100,200,300and the arm body33in the mold500, the lower surface510of the mold500may be in contact with the matching surface111,211,311of the matching portion110,210,310.

In addition, the arm body33may be manufactured by a burring process. Specifically, curved portions, which are connection portions between the first to the third extended portion33a,33b,33cof the arm body33may be formed by the burring process.

The burring process may comprise drilling a hole in a flat steel plate; widening the hole to deform an edge of the hole in a cylindrical shape by press-punching to widen the hole; and forming the first extended portion33athat is to be coupled to the welding surface130,230,330formed on the outer peripheral portion of the housing100,200,300. At this time, the welding surfaces130,230,330and the inner peripheral surface33dof the first extended portion33amay be coupled to each other.

Further, in the step of coupling the arm body33to the outer peripheral surface of the housing100,200,300by welding, the welding may be an arc welding which supplies heat necessary for the welding through an electric arc generated between the welding rod and the welding target portion. In addition, the step of coupling the arm body33to the outer peripheral surface of the housing100,200,300by welding may be performed on at least one welding surface130,230,330formed in a length of 10 mm to 15 mm along the circumferential direction on the outer peripheral surface of the housing100,200,300.

In the present embodiment, since the lower surface510of the mold500is in contact with the matching surface111,211,311, the housing100,200,300, the ball stud31and the like can be stably fixed in the mold500. Further, since the lower surface510of the mold500and the matching surface111,211,311are in contact with each other, the plastic insert-molding material injected upward from the lower portion of the ball stud31can be prevented from flowing into a region above the matching surface111,211,311and the mold500. Thus, it is possible to prevent the insert molding part36from being formed in the region above the matching surface111,211,311. In addition, when the matching surface111,211,311of the matching portion110,210,310and the lower surface510of the mold500are matched with each other, the molding material can be prevented from flowing into the dust cover coupling portion103,203,303during the injection process of the molding. In addition, by decreasing the radial thickness t of the housing100,200,300except for the matching portion110(210,310), it is possible to reduce the weight of the suspension arm1.

Although the technical spirit of the present disclosure has been described using some embodiments and examples shown in the accompanying drawings, it should be noted that various substitutions, modification, and variations can be devised by those skilled in the art to which the present disclosure pertains without departing from the technical spirit and scope of the present disclosure. Further, it should be construed that these substitutions, modifications, and variations are included within the scope of the appended claims.