Vehicle support structure and method for manufacturing vehicle support structure

Abstract

To provide a support structure for a vehicle and manufacturing method of the support structure for the vehicle which is provided with a working standard hole which can support a casting surely by inserting a jig for positioning during machining and at the same time prevents water from being accumulated in such a condition as to install on the vehicle.SOLUTION: A suspension arm manufactured by casting includes a working standard hole 7 which is formed at casting. The working standard hole 7 is formed long in a curve direction of the suspension arm which generates in molding process. There is formed a concave part 8 which allows one end to pass through the working standard hole 7 and at the same time allows other end to open to outside.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a vehicle support structure and a method for manufacturing a vehicle support structure, and more particularly to a vehicle support structure manufactured by casting, which has a machining reference hole used for positioning when machining the cast body after casting, and a method for manufacturing the vehicle support structure. [Background technology]

[0002] Conventionally, in vehicle support structures manufactured by casting, a jig is inserted into a machining reference hole provided in the casting after the molding process is completed, and the casting is positioned while being machined (processing process), and this machining reference hole is formed by a core during the molding process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2007-506924 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned Patent Document 1, the machining reference hole may be misaligned due to deformation such as bending of the casting during the molding process, and a positioning jig may not be able to be inserted into the machining reference hole deformed during machining, or even if it can be inserted, the machining reference hole may not be supported reliably by the jig. Furthermore, water may accumulate in the machining reference hole of the vehicle support structure mounted on the vehicle, causing corrosion, and there is a risk of a decrease in strength.

[0005] Therefore, the present invention aims to provide a vehicle support structure and a method for manufacturing a vehicle support structure that are equipped with a machining reference hole that allows a positioning jig to be inserted during machining to securely support the casting and prevents water from accumulating when mounted on a vehicle. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the vehicle support structure of the present invention is a vehicle support structure manufactured by casting, and is characterized in that the vehicle support structure has a machining reference hole formed during casting, the machining reference hole is formed long in the bending direction of the vehicle support structure that occurs in the molding process, and a recess is formed with one end passing through the machining reference hole and the other end open to the outside.

[0007] It is also preferable that the bottom of the machining reference hole and the bottom of the recess are gradually inclined downward in the direction of gravity toward the other end of the recess.

[0008] Furthermore, it is preferable that the vehicle support structure is a suspension arm, and the machining reference hole is disposed on an upper surface of the suspension arm when the suspension arm is mounted on a vehicle, and around a connection portion for connecting another component.

[0009] In addition, the manufacturing method for a vehicle support structure of the present invention is a manufacturing method for a vehicle support structure manufactured by casting, and is characterized in that the vehicle support structure is molded during casting with a long machining reference hole that is aligned along the bending direction of the vehicle support structure generated in the molding process, and a recess having one end passing through the machining reference hole and the other end open to the outside.

[0010] Furthermore, the molding step includes a heat treatment step, and the bending direction of the vehicle support structure is the same as the bending direction generated during the heat treatment step.

[0011] The molding process includes a demolding process, and the bending direction of the vehicle support structure is the same as the bending direction generated during the demolding process. Effect of the Invention

[0012] According to the vehicle support structure of the present invention, since the machining reference hole is formed long along the bending direction of the vehicle support structure, even if bending occurs during casting and the machining reference hole is misaligned in the bending direction, a positioning jig can be inserted into the machining reference hole, and the jig can be abutted against the side wall in the width direction of the machining reference hole to reliably support the machining reference hole with the jig. Furthermore, even if water enters the machining reference hole when the vehicle support structure is mounted on the vehicle, the entered water can be discharged by the recess, and water can be prevented from accumulating in the machining reference hole.

[0013] In addition, by gradually inclining the bottom of the machining reference hole and the bottom of the recess toward the other end of the recess in the direction of gravity, water that has entered the machining reference hole can be reliably discharged, and water does not accumulate in the machining reference hole. This also prevents the machining reference hole from being corroded by water, and when the machining reference hole is provided near a connection portion for another component, there is no risk of the machining reference hole affecting the connection portion for another component by corrosion.

[0014] Furthermore, according to the manufacturing method for the vehicle support structure of the present invention, the processing reference hole and the recessed portion can be easily formed.

[0015] Furthermore, by forming the machining reference hole to be long in the direction of bending that occurs during the heat treatment process or the direction of bending that occurs during the demolding process, even if bending occurs and causes a positional shift in the bending direction of the machining reference hole and the recess, a positioning jig can be inserted into the machining reference hole, and by abutting the jig against the widthwise side wall of the machining reference hole, the machining reference hole can be reliably supported by the jig. [Brief description of the drawings]

[0016] [Figure 1]1 is a plan view of a suspension arm showing an example of the present invention. FIG. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] 1 is an explanatory diagram of a suspension arm showing an example of the present invention; [Figure 4] FIG. 13 is a plan view of a main portion of a casting of a suspension arm in which a machining reference hole and a recess are molded. [Diagram 5] FIG. 5 is a cross-sectional view of FIG. 4 . [Figure 6] FIG. 13 is a plan view of a main portion of a casting of a suspension arm in which a machining reference hole is formed. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1 to 7 show an example in which the present invention is applied to a suspension arm, which is an example of a vehicle support structure, and a suspension arm 1 of this example is attached as a lower arm of a rear wheel of a vehicle.

[0018] The suspension arm 1 comprises an arm body 2a, a vehicle body side arm 2b extending from the arm body 2a towards the vehicle body side, and a wheel side arm 2c extending from the arm body 2a towards the wheel side, with a vehicle body side bearing 3 provided at the tip of the vehicle body side arm 2b and a wheel side bearing 4 provided at the tip of the wheel side arm 2c. The arm body 2a is formed in a concave shape with a bottom wall 2d and a side wall 2e extending upward from the bottom wall 2d, with a circular portion 2f formed on the wheel side arm 2c side and an opening 2g formed on the vehicle body side arm 2b side. A shock absorber connecting portion 2h is protruded from the center of the circular portion 2f, and a shock absorber (not shown) including a suspension spring 5, a rubber ring 6 for cushioning, etc. is connected to the shock absorber connecting portion 2h.

[0019] A machining reference hole 7 and a recess 8 are integrally formed on the upper surface of the tip of the vehicle body side arm 2b (the boundary between the machining reference hole 7 and the recess 8 is shown by an imaginary line in FIG. 5). The machining reference hole 7 is formed longer in the bending direction (the direction of arrow A shown in FIG. 2) than in the width direction of the vehicle body side arm 2b, and has a bottom 7a and a side wall 7b. The recess 8 has one end connected to the machining reference hole 7 and the other end open outward to the tip of the vehicle body side arm 2b. The bottom 8a of the recess 8 is formed flush with the bottom 7a of the machining reference hole 7, and the bottoms 7a, 8a are formed so as to gradually incline downward in the direction of gravity toward the tip side of the vehicle body side arm 2b (the other end side of the recess).

[0020] The suspension arm 1 as described above is manufactured by a well-known casting method in which a molten metal filling process is performed in which molten metal of a metal such as aluminum is poured into and filled into a cavity of a molding die (the molding die and each die are not shown) equipped with a main die, a movable die, and a core for forming the processing reference hole 7 and the recess 8, a demolding process is performed in which the main die and the movable die are opened and the casting 1a is removed from the molding die, a gate cutting process is performed in which the gate is cut off from the casting 1a, and a heat treatment process is performed in which the casting 1a is heated at high temperature for a fixed period of time, then quickly water-cooled, and the water-cooled casting is further heated for a fixed period of time, and so on. After this molding process, a processing process such as cutting is performed.

[0021] In the heat treatment process, bending (bending in the direction of arrow A in Fig. 2) may occur in the vehicle body side arm portion 2b, which is the long portion. In the demolding process, the movable die is opened while pushing the casting 1a with a demolding pin, and then the casting 1a remaining in the main die is removed from the main die while being pushed with the demolding pin. However, bending similar to that which occurs in the heat treatment process (bending in the direction of arrow A in Fig. 2) may occur in the casting 1a due to the balance of the pushing strength of the demolding pin or the casting 1a getting caught in the main die or the movable die.

[0022] In this embodiment, the machining reference hole 7 is formed long in the bending direction of the vehicle body side arm portion 2b (the direction of arrow A shown in Figure 2). Therefore, even if bending as described above occurs and the machining reference hole 7 and recess 8 become misaligned in the bending direction, when a jig 9 is inserted into the machining reference hole 7 (Figure 4) and the casting 1a is positioned and machining (processing step) is performed, the positioning jig 9 can be inserted into the machining reference hole 7, and the jig 9 can be abutted against the widthwise side walls 7b, 7b of the machining reference hole 7, thereby reliably supporting the machining reference hole 7 with the jig 9.

[0023] In addition, by providing a recess 8 with one end connected to the machined reference hole 7 and the other end open outward to the tip of the vehicle body side arm 2b, even if water infiltrates into the machined reference hole 7 when the suspension arm 1 is mounted on a vehicle, the infiltrated water can be discharged by the recess 8. Furthermore, the bottom 7a of the machined reference hole 7 and the bottom 8a of the recess 8 are formed flush with each other and are formed to gradually incline downward in the direction of gravity toward the tip of the vehicle body side arm 2b, so that the infiltrated water can be reliably discharged. Furthermore, water does not accumulate in the machined reference hole 7, so corrosion due to water can be prevented, and the vehicle body side bearing portion 3 (the other component connection portion of the present invention) is not affected by corrosion.

[0024] Furthermore, since the machining reference hole 7 and the recess 8 are molded by a core during casting, the machining reference hole 7 and the recess 8 can be easily formed.

[0025] In the above embodiment, the machining reference hole 7 and the recess 8 are formed by a core during casting, but as shown in Figures 6 and 7, the machining reference hole 10 can be formed by a core during casting, and then the recess can be formed by cutting by machining, with one end of the recess being cut so as to communicate with the machining reference hole 10 and the other end being open to the outside. The machining reference hole 10 has the same shape as the machining reference hole 7 including the imaginary line in Figure 5, and is formed so that the diameter of the hole is longer in the bending direction than in the width direction of the body side arm portion 2b.

[0026] Furthermore, the vehicle support structure of the present invention is not limited to a suspension arm as in the above-mentioned embodiment, but includes various parts such as a knuckle that connects and supports each part such as a hub bearing and an arm, and various arm members that support the vertical movement of the knuckle and suppress the lateral movement of the vehicle body. [Explanation of symbols]

[0027] Reference Signs List 1...suspension arm, 1a...cast body, 2a...arm body, 2b...vehicle body side arm, 2c...wheel side arm, 2d...bottom wall, 2e...side wall, 2f...circular portion, 2g...opening, 2h...shock absorber connecting portion, 3...vehicle body side bearing portion, 4...wheel side bearing portion, 5...suspension spring, 6...rubber ring, 7...machining reference hole, 7a...bottom, 7b...side wall, 8...recess, 8a...bottom, 9...jig, 10...machining reference hole

Claims

1. A vehicle support structure manufactured by casting, the vehicle support structure having a machining reference hole formed at the time of casting, the machining reference hole being formed long in the bending direction of the vehicle support structure that occurs during a molding process, and a recess having one end passing through the machining reference hole and the other end open to the outside.

2. 2. The vehicle support structure according to claim 1, wherein a bottom of the machining reference hole and a bottom of the recess are gradually inclined downward in the direction of gravity toward the other end of the recess.

3. 3. The vehicle support structure according to claim 1, wherein the vehicle support structure is a suspension arm, and the machining reference hole is arranged on the upper surface of the suspension arm when the suspension arm is mounted on a vehicle, and around a connection portion for connecting to other components.

4. A manufacturing method for a vehicle support structure manufactured by casting, characterized in that the vehicle support structure is molded during casting with a machining reference hole that is long along the bending direction of the vehicle support structure generated in a molding process, and a recess having one end passing through the machining reference hole and the other end open to the outside.

5. 5. The method for manufacturing a vehicle support structure according to claim 4, wherein the molding step includes a heat treatment step, and the bending direction of the vehicle support structure is the same as the bending direction generated during the heat treatment step.

6. 5. The method for manufacturing a vehicle support structure according to claim 4, wherein the molding process includes a demolding process, and the bending direction of the vehicle support structure is the same as the bending direction generated during the demolding process.

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