KR20080068204A - Method for manufacturing control arm - Google Patents

Abstract

A method for manufacturing a control arm is provided to form a plane shape of the control arm and to form a curved part on the control arm vertically for removing a trimming process and for carrying out a forging process continuously. An original material(100) is bent to form a curved part(103). The curved part is forged to form a control arm. The control arm has upper and lower arms. The upper arm includes a rod shaped body(109), an operating body(105) connected with a knuckle by a ball joint, and first and second bush parts(106,107) connected with a vehicle body. The original material has a large diameter part(102) which is not processed, and a small diameter part(101) whose diameter is reduced.

Description

Method for manufacturing control arm

1 is a simplified view of a control arm manufacturing method according to an embodiment of the present invention.

Figure 2 is a simplified view of the bending device.

Figure 3 is a side view after processing and bending the raw material.

4 is a plan view of the upper arm completed according to the control arm manufacturing method according to a preferred embodiment of the present invention.

5 is an upper arm side view of FIG. 4.

6 is a simulation result when the bending of the raw material.

7 is a simulation result when the first forging of the raw material.

8 is a simulation result when the second forging of raw materials.

9 is a perspective view of a conventional lower arm.

** Description of symbols for the main parts of the drawing **

100: raw material 101: small diameter portion

102: large diameter 103: bending portion

105: operating unit 106: first bushing

107: second bush 108: interval between

109: body 111: first bent portion

112: second bent portion 113: the first bent portion

114: second bend portion 115: third bend portion

121: inner round part 122: outer round part

123: protrusion 210: punch

220: die 211: punch projection

221: forming groove 222: inclined surface

223: home

Korean Laid-Open Patent No. 1999-52430

The present invention relates to a control arm manufacturing method, in particular, comprising a bending step of forming a bent portion by bending the raw material, and a forging step of forming the control arm by forming the bent portion in a forging, even if the forging molding The present invention relates to a control arm manufacturing method which reduces production cost by reducing loss of raw materials.

Suspension of a vehicle is a device that connects the axle and the vehicle body so that the vibration or shock received from the road surface when the vehicle is driving is not directly transmitted to the vehicle body, thereby preventing damage to the vehicle body or cargo and improving ride comfort. In particular, the front suspension is connected between the frame and the axle to support the weight of the vehicle, absorbs vibrations generated from the wheels, and at the same time, the steering device of the vehicle is installed in some front suspension. The front suspension system is divided into the axle suspension type and the independent suspension type according to the type of the front axle.In general, the independent suspension type is used in the case of a passenger car that emphasizes the comfort and maneuverability, and the axle suspension type is frequently used in the bus or truck.

The most typical independent suspension front suspension is the wishbone type, which has two V-shaped suspension arms mounted on the frame by the shaft, and the end of each arm is the ball joint. Is coupled to the steering knuckle of the wheel. In this type, the braking force and the cornering force generated in the wheel are supported by the suspension arm, and the suspension spring supports only the load in the vertical direction, and the lower arm supports the lower end of the suspension spring.

Conventional vehicle suspension lower arm manufacturing method is that disclosed in Korea Patent Publication No. 1999-52430.

The method of manufacturing a lower arm of an automobile suspension device firstly has a shaft diameter such that both ends of a pipe-like material 1 having a diameter of 50 mm and a thickness of 3 mm and a tensile strength of 45 kgf / mm 2 have a diameter of 40 mm, for example. Form part 2. The method of reducing both ends of the raw material 1 utilizes swaging (cold forging) processing to give compactness of the tissue.

Then, the swaged material 1 is bent in the middle portion such that the shaft diameter portion 2 at both ends has a diameter of 40 mm. The intermediate part is bent so that the material 1 having the same length on both sides is hydraulically molded (hydroformed), so that the raw material 1 is widely developed to have the shape of the left and right lower arms having symmetrical shapes with each other.

The raw material 1 which is developed such that the raw material 1 has a shape of a lower arm on the left and right side is cut into a lower arm on the left and right sides by cutting the bent intermediate portion, and the shaft diameter portion formed at the end of each separated lower arm ( 2) is forged to form a spindle 3 having a diameter of 18 mm, and an end portion of the spindle 3 is rolled to form a screw 4 having a diameter of 12.5 mm.

However, the conventional lower arm manufacturing method is subjected to a process such as swaging-> intermediate part bending-> intermediate part hydraulic molding-> shaft diameter part forging-> spindle end rolling, and the production process is complicated, and thus the production time There is this long problem.

 The present invention has been made in order to solve the above problems, and comprises a bending step of forming a bent portion by bending the raw material, and a forging step of forming the control arm by forming the bent portion in a forging, even if forged molding It is an object of the present invention to provide a control arm manufacturing method which reduces production loss due to the loss of raw materials.

The control arm manufacturing method of the present invention for achieving the above object is characterized in that it comprises a bending step of forming a bent portion by bending the raw material, and a forging step of forming the control arm by forming the bent portion in a forging. .

According to this structure, even if forging molding, the loss of the raw material to be introduced is reduced, there is an advantage that the production cost is reduced.

Before the bending step, further comprising a processing step of reducing the diameter of one side of the raw material, processing only one side without processing the raw material as a whole, the production time is shortened, the shape of the overall control arm by processing before bending By forming approximately to reduce the portion to be additionally molded can maintain the strength of the product to the maximum.

The forging step may include a first forging for forming a planar shape of the control arm and a second forging for forming a bent portion in the up and down direction on the control arm, thereby effectively forming a complicated shape of the control arm. The trimming step is omitted, and the production time is shortened by forging continuously.

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

For reference, among the configurations of the present invention to be described below, the same configuration as the prior art will be referred to the above-described prior art, and a detailed description thereof will be omitted.

Figure 1 is a simplified view of a control arm manufacturing method according to a preferred embodiment of the present invention, Figure 2 is a simplified view of the bending device, Figure 3 is a side view after processing and bending the raw material, Figure 4 is a preferred embodiment of the present invention The upper arm is a plan view completed according to the control arm manufacturing method according to, Figure 5 is an upper arm side view of FIG.

As shown in Figures 1 to 5, the control arm manufacturing method of the present embodiment, the bending step of forming the bending portion 103 by bending the raw material, and forming the control portion by forging the bending portion 103 It comprises a forging step to form.

The control arm includes an upper arm and a lower arm disposed below the upper arm. In the present embodiment, the manufacturing method of the upper arm among the wishbone type control arms of the automobile suspension system is described as an example. However, the lower arm may be molded in the same manner.

The upper arm is formed at one end of the rod-shaped body 109 and the body 109 and is connected to the knuckle by a ball joint, and a first part connected to both sides of the other end of the body 109 and connected to the vehicle body. The bush 106 and the second bush 107 are included. The axis passing through the center of the operating part 105 is disposed in the vertical direction, and the axis passing through the center of the first bushing part 106 and the second bushing part 107 is disposed in the front-rear direction so that the two axes are perpendicular to each other.

As shown in FIG. 4, when viewed in a plan view, the body 109 is formed such that the second bent portion 112 is proximate to the operating portion 105 in a convex manner toward the first bushing portion 106. The first bent part 111 is formed to be convex toward the second bush part 107 so as to be disposed between the bent part 112, the first bush part 106, and the second bush part 107.

The first bushing part 106 and the second bushing part 107 are formed to be spaced apart from each other such that an interval 108 is formed between the first bushing part 106 and the second bushing part 107. The portion 106 is formed to be farther from the body 109 than the second bush portion 107.

The third curved portion 115 is formed to be convex downward in the middle portion of the body 109 so that the side shape of the upper arm is generally formed in a 'V' shape.

In addition, a second bent portion 114 is formed in the body 109 to be convex upward in the body 109 so as to be close to the operating portion 105, so that the operating portion 105 is disposed horizontally.

The first bent portion 113 is formed to be convex upward in a portion where the first bush portion 106 and the second bush portion 107 are branched from the body 109 to the portion where the second bush portion 107 is connected. .

In order to process the raw material 100, a heating step of heating to a high temperature is started.

The raw material 100 is formed in a rod-like shape with a cross section.

A processing step of reducing the diameter of the upper side of the one side of the raw material 100 is performed. That is, the processing step varies the diameter of one side of the raw material 100.

Through the processing step, the raw material 100 includes a large diameter portion 102 that is not processed and a small diameter portion 101 whose diameter is reduced through processing. In addition, the entire length of the raw material 100 is longer than before processing.

The small diameter portion 101 is formed above the large diameter portion 102, and the length of the large diameter portion 102 is shorter than that of the small diameter portion 101.

The connecting portion of the small diameter portion 101 and the large diameter portion 102 is formed with an inclined surface on the outer circumferential surface so that the cross-sectional area is gradually smaller toward the small diameter portion 101 from the large diameter portion 102.

As such, the production time is shortened by processing only one side without processing the raw material 100 as a whole, and roughly forms the overall upper arm shape by processing before bending, thereby reducing the additional portion to be molded. Can be kept as long as possible.

When the forging is performed immediately after the processing step, an elongated body 109 due to the shape of the upper arm, an operating part 105 formed at the upper end of the body 109, a gap between both sides of the lower end of the body 109 ( Due to the two bush portions 107 and 106 formed far from 108, a lot of loss of the input material occurs. This is much lower than the average recovery rate (about 75%) of ordinary hot forgings.

Therefore, in order to solve this problem, the present embodiment includes a bending step of forming the bent portion 103 by bending the raw material 100.

The bending step is to bend the large diameter portion 102 of the raw material 100 to form a bent portion (103).

The bending device includes a die 220 and a punch 210 disposed above the die 220 and moving up and down.

In the die 220, a molding groove 221 is formed on the top surface of the die 220 such that the raw material 100 is bent in an eccentric manner.

The molding groove 221 is formed to correspond to the shape of the bent portion 103 to be molded.

The forming groove 221 has an arc-shaped arc surface formed at the bottom, the inclined surface 222 is formed on both sides of the arc surface.

The inclination angle of the portion closer to the end of the large diameter portion 102 is greater than the portion close to the small diameter portion 101 on the inclined surface 222.

In addition, a groove 223 is formed on the upper surface of the die 220 so as to be disposed under the small diameter portion 101 and communicate with the molding groove 221. The depth of the groove 223 is formed shallower than the forming groove 221.

The punch 210 has a punch protrusion 211 is formed at a position corresponding to the forming groove 221 eccentrically on one side.

The punch protrusion 211 is formed in a triangular shape, the inclined surface is formed on both sides to correspond to the inclined surface 222 on both sides.

Since the banding device as described above is presented in Korean Patent Laid-Open No. 10-2005-0034500, details thereof will be referred to.

In the bending step, the large diameter portion 102 of the raw material 110 is placed on the forming groove 221 on the die 220 of the bending device, and then the punch 210 is moved downward. When the bending groove 103 is formed in the shape between the forming groove 221 and the punch protrusion 211.

Thus, as shown in FIG. 3, the raw material 100 formed through the bending step is formed with a bent portion 103 bent to the left under the small-diameter portion 101 and is formed in a '' '' shape as a whole. Specifically, in the raw material 100, the large-diameter portion 102 is pressed by the punch protrusion 211, and the inner round portion 121 is formed inside the bent portion of the bent portion 103, and the molding groove 221 is formed in the molding groove 221. The outer round part 122 having a center angle larger than the arc center angle of the inner round part 121 is formed on the outer side of the bent portion, and the protruding part 123 is formed outside the end of the large diameter part 102.

The protrusion 123 may be formed at the end of the bent portion 103 during forging, and the first bushing portion 106 arranged in the direction in which the body 106 is disposed may be formed without loss of material.

In addition, the outer round part 122 is formed to protrude more than the small diameter part 101 without being continuous to the small diameter part 101. As such, the outer round part 122 may be formed to form the second bush part 107 formed in the opposite direction to the first bush part 106 during forging.

In the forging step, the bent part 103 is formed by forging using a forging press device to form an upper arm.

The forging step includes a first forging for forming a planar shape of the upper arm and a second forging for forming a bent portion in the vertical direction on the upper arm.

In the forging step, the small diameter portion 101 is formed of the upper arm body 109 and the operating portion 105 formed on the upper portion of the body 109 through a forging die, and the bent portion 103 is formed by the first bushing portion ( 106 and the outer round part 122 is formed as the second bush part 107.

The first forging is formed by forming a bent portion 103 in a die in which a molding space corresponding to a planar shape of the upper arm is formed, and when forging is performed, the body 109, the operating portion 105, and the first bushing portion of the upper arm ( 106, a second bush portion 107 is formed. In addition, the first bent part 111 and the second bent part 112 are also formed through the first forging.

The second forging has a bent groove having a cross-sectional shape of 'V' so as to correspond to the side shape of the upper arm in the front and rear direction in the lower die to form a bent portion in the vertical direction of the first forged raw material 100.

The bent part includes a first bent part 113, the second bent part 114, and a third bent part 115 of the upper arm.

When the body 109 is disposed on the bent groove, the actuating part 105 and the first bushing part 106 and the second bushing part 107 are placed on the die top of the forging device and then forged. The first bent part 113, the second bent part 114, and the third bent part 115 are formed.

In this way, by manufacturing the upper arm through the two forgings, the complex shape of the upper arm can be effectively formed, and the trimming step is omitted in the middle, and the production time is shortened by continuously forging.

On the other hand, if the raw material is heated without a bending step and then subjected to a forging step using an air drop hammer through a processing step, and then trimmed to produce an upper arm, a recovery rate is 59% (product weight: 3.6 kg / input weight: 5.1). kg), mold life is 5000ea, production quantity is 150ea / hr (max), and production cost is \ 6,244 / ea. In addition, if the production in the air drop hammer (air drop hammer) equipment in this way there is a problem in customer delivery due to the lack of production capacity compared to the production requirements.

The raw material is heated, processed and banded, then forged and trimmed using a forging press to produce upper arms. The recovery rate is 70% (product weight: 3.6kg / input weight: 5.1kg), and the mold life is 7000ea. Production quantity is 200ea / hr (min) and production cost is \ 5,368 / ea.

It is possible to work on forging press equipment to secure production efficiency compared to the requirements, and the cost reduction is 369 million won / year compared to the air drop hammer due to the improved recovery rate.

In addition, the overall cost of producing upper arms is reduced by $ 525 million / year compared to air drop hammers. In addition, the production time is shortened to ensure the surplus time of the equipment.

As described above, when the raw material 100 is forged after bending the raw material 100 according to the shape of the upper arm, even if the forging is performed, loss of raw material to be injected is reduced, thereby reducing the production cost.

6 to 8 is a diagram simulating the stress generated during manufacturing according to the upper arm manufacturing method of the present invention. In the drawing, the color indicates that the intensity is closer to blue and the intensity is closer to red.

6 shows the change in strength of the raw material 100 when the raw material 100 is banded 0%, 50%, 100%, as shown in the figure, by bending the large diameter portion 102 that has not been processed, thereby changing the strength. Appears not to be large.

In FIG. 7, when the raw material 100 is bent in 0%, 50%, and 100% after the first bending, the raw material 100 is bent in the shape of the upper arm, thereby reducing the loss of the input material. have. In addition, it can be seen that the strength of the portion to be a product does not drop significantly, and the strength of the operating portion 105, the first bushing portion 106, and the second bushing portion 107 is maintained.

In FIG. 8, when 0%, 50%, and 100% second forging is performed after the first forging, it can be seen that there is almost no change in strength compared to the first forging.

Subsequently, in the forging step, a trimming step of cutting or shearing the excess material portion formed in the raw material 100 to complete the product is performed.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified or modified within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. It can be modified.

According to the control arm manufacturing method of the present invention as described above, has the following advantages.

It includes a bending step of bending the raw material to form a bent portion, and a forging step of forming the control arm by forming the bent portion in a forging, the control to reduce the production cost by reducing the loss of raw materials to be injected even in the forging molding It relates to a method for producing cancer.

Before the bending step, further comprising a processing step of changing the diameter of the one side of the raw material, processing only one side without processing the raw material as a whole, the production time is shortened, the shape of the overall control arm by processing before bending By forming approximately to reduce the portion to be additionally molded can maintain the strength of the product to the maximum.

The forging step may include a first forging for forming a planar shape of the control arm and a second forging for forming a bent portion in the up and down direction on the control arm, thereby effectively forming a complicated shape of the control arm. The trimming step is omitted, and the production time is shortened by forging continuously.

Claims (3)

Bending the raw material to form a bent portion; And a forging step of forming the control arm by forging the bent portion to form the control arm. The method of claim 1, Before the bending step, Control arm manufacturing method characterized in that it further comprises a processing step of reducing the diameter of one side of the raw material. The method according to claim 1 or 2, The forging step includes a first forging to form a planar shape of the control arm and a second forging to form a bent portion in the vertical direction on the control arm.

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