Support structure for vehicle and method for manufacturing support structure for vehicle

Abstract

The present invention provides a vehicle support structure and a method for manufacturing the vehicle support structure, the vehicle support structure being provided with a machining reference hole, the machining reference hole allowing a positioning jig to be inserted during machining to reliably support a cast body, and preventing water from accumulating in a state in which the vehicle support structure is mounted on a vehicle. The suspension arm manufactured by casting has a machining reference hole (7) formed during casting. The machining reference hole (7) is formed to be longer in the direction of the bend generated in the molding step of the suspension arm. A recess (8) is formed on the suspension arm, one end of the recess (8) is communicated with the machining reference hole (7), and the other end of the recess (8) is opened outwards.

Description

Technical Field

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

[0002] Conventionally, in a vehicle support structure manufactured by casting, a jig is inserted into a machining reference hole provided in a casting after a molding process is completed, and machining (machining process) is performed with the casting positioned. The machining reference hole is formed by a core during the molding process (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2007-506924 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] 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 the positioning jig cannot be inserted into the deformed machining reference hole during machining, or even if the jig can be inserted, the machining reference hole cannot be reliably supported by the jig. In addition, water may accumulate in the machining reference hole of the vehicle support structure mounted on the vehicle, causing corrosion, which may reduce the strength.

[0008] Therefore, an object of the present invention is to provide a vehicle support structure and a method for manufacturing a vehicle support structure, wherein the vehicle support structure has a machining reference hole that allows a positioning jig to be inserted during machining to reliably support the casting and can prevent water from accumulating when the casting is mounted on a vehicle.

[0009] Solutions for solving problems

[0010] In order to achieve the above-mentioned purpose, the vehicle support structure of the present invention is a vehicle support structure manufactured by casting, characterized in that the vehicle support structure has a processing reference hole formed during casting, the processing reference hole is formed longer in the direction of the bending generated in the forming process of the vehicle support structure, and the vehicle support structure is formed with a recessed portion, one end of which is connected to the processing reference hole and the other end is open to the outside.

[0011] In addition, it is preferable that the bottom of the machining reference hole and the bottom of the recessed portion are gradually inclined downward in the gravity direction toward the other end side of the recessed portion.

[0012] Furthermore, it is preferable that the vehicle support structure is a suspension arm, and the machining reference hole is arranged on an upper surface of the suspension arm in a state in which the suspension arm is mounted on a vehicle and around a connection portion with another member.

[0013] In addition, the manufacturing method of the vehicle support structure of the present invention is a manufacturing method of the vehicle support structure manufactured by casting, characterized in that the vehicle support structure is formed with a processing reference hole and a recessed portion during casting, the processing reference hole is longer along the direction of the bending generated in the forming process of the vehicle support structure, one end of the recess is connected to the processing reference hole and the other end is open to the outside.

[0014] Furthermore, the molding step includes a heat treatment step, and the direction in which the vehicle support structure is bent is the same as the direction in which the bending occurs during the heat treatment step.

[0015] Furthermore, the molding step includes a mold releasing step, and the direction in which the vehicle support structure is bent is the same as the direction in which the support structure is bent during the mold releasing step.

[0016] Effects of the Invention

[0017] According to the vehicle support structure of the present invention, the machining reference hole is formed to be longer along the bending direction of the vehicle support structure, so that even if bending occurs during casting and the machining reference hole is misaligned in the bending direction, the positioning jig can be inserted into the machining reference hole, and the jig can be brought into contact with the side wall of the machining reference hole in the width direction, so that the machining reference hole can be reliably supported by the jig. In addition, when the vehicle support structure is mounted on the vehicle, even if water penetrates into the machining reference hole, the recessed portion can be used to drain the penetrated water, so that water can be prevented from accumulating in the machining reference hole.

[0018] In addition, by gradually tilting the bottom of the machining reference hole and the bottom of the recessed portion downward in the direction of gravity toward the other end of the recessed portion, water that has entered the machining reference hole can be reliably discharged, and water will not accumulate in the machining reference hole. In addition, this prevents the machining reference hole from being corroded by water, and when the machining reference hole is set near the connection part of other components, there is no need to worry about the influence of corrosion on the connection part of other components.

[0019] Furthermore, according to the method for manufacturing a vehicle support structure of the present invention, the machining reference hole and the recessed portion can be easily formed.

[0020] In addition, by forming the machining reference hole longer along the direction of the bending generated during the heat treatment process and the direction of the bending generated during the demolding process, even if bending occurs and misalignment occurs in the bending direction between the machining reference hole and the recessed portion, the positioning jig can be inserted into the machining reference hole, and the jig can be brought into contact with the side wall of the machining reference hole in the width direction, thereby reliably supporting the machining reference hole using the jig. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top view showing a suspension arm according to an embodiment of the present invention.

[0022] Figure 2 yes Figure 1 II-II sectional view.

[0023] Figure 3 It is an explanatory diagram showing a suspension arm according to an embodiment of the present invention.

[0024] Figure 4 This is a plan view of the main parts of the casting of the suspension arm in which the reference hole and the recessed portion are similarly formed.

[0025] Figure 5 yes Figure 4 VV cross-sectional view of.

[0026] Figure 6 This is a plan view of the main parts of a casting body of a suspension arm in which a reference hole is similarly formed.

[0027] Figure 7 yes Figure 6 VII-VII sectional view.

[0028] Description of Reference Numerals

[0029] 1. Suspension arm; 1a. Casting body; 2a. Arm body; 2b. Body side wrist; 2c. Wheel side wrist; 2d. Bottom wall; 2e. Side wall; 2f. Round part; 2g. Opening; 2h. Shock absorber connection part; 3. Body side bearing; 4. Wheel side bearing; 5. Suspension spring; 6. Rubber ring; 7. Processing reference hole; 7a. Bottom; 7b. Side wall; 8. Concave part; 8a. Bottom; 9. Jig; 10. Processing reference hole. DETAILED DESCRIPTION

[0030] Figure 1 to Figure 7 The figure shows one embodiment of a suspension arm applied to an example of a support structure for a vehicle. The suspension arm 1 of this embodiment is attached as a lower arm of a rear wheel of a vehicle.

[0031] The suspension arm 1 includes an arm body 2a, a vehicle body side arm 2b extending from the arm body 2a to the vehicle body side, and a wheel side arm 2c extending from the arm body 2a to the wheel side, a vehicle body side bearing 3 being provided at the top end of the vehicle body side arm 2b, and a wheel side bearing 4 being provided at the top end of the wheel side arm 2c. The arm body 2a is formed into a concave shape including a bottom wall 2d and a side wall 2e extending upward from the bottom wall 2d, and a circular portion 2f is formed on the wheel side arm 2c side of the bottom wall 2d, and an opening portion 2g is formed on the vehicle body side arm 2b side. A shock absorber connecting portion 2h is protrudingly provided at the center of the circular portion 2f, and a shock absorber (not shown) including a suspension spring 5, a rubber ring 6 for buffering, etc. is connected to the shock absorber connecting portion 2h.

[0032] A machining reference hole 7 and a recess 8 are integrally formed on the upper surface of the top end of the vehicle body side arm 2b (the boundary between the machining reference hole 7 and the recess 8 is defined by Figure 5 Compared with the width direction of the vehicle body side arm 2b, the processing reference hole 7 is in the bending direction ( Figure 2 The recess 8 is formed long in the direction of the arrow A shown in FIG. 1 and has a bottom 7a and a side wall 7b. The recess 8 is connected to the processing reference hole 7 at one end and is opened to the outside of the top end of the body side arm 2b at the other end. The bottom 8a of the recess 8 is formed flush with the bottom 7a of the processing reference hole 7, and the bottoms 7a and 8a are formed so as to gradually tilt downward in the direction of gravity toward the top end side (the other end side of the recess) of the body side arm 2b.

[0033] The above-mentioned suspension arm 1 is manufactured using the well-known casting method as follows: after the molding steps such as the molten metal filling step, the demolding step, the gate cutting step, and the heat treatment step are completed in sequence, the processing steps such as cutting are carried out. In the molten metal filling step, the molten metal of the metal such as aluminum flows and is filled into the mold cavity of the forming mold (the forming mold and each mold are not shown) having a main mold and a movable mold and a core for molding the processing reference hole 7 and the recessed portion 8. In the demolding step, the main mold and the movable mold are opened to remove the casting 1a from the forming mold. In the gate cutting step, the gate is cut off from the casting 1a. In the heat treatment step, the casting 1a is heated at a high temperature for a certain period of time, and then quickly water-cooled, and the water-cooled casting is further heated for a certain period of time.

[0034] During the heat treatment process, the body side arm portion 2b, which is the longitudinal portion, may be bent. Figure 2In addition, in the demolding process, the casting 1a is opened while the demolding pin is used to press the casting 1a, and then the casting 1a remaining in the main mold is removed from the main mold while the demolding pin is used to press the casting 1a. However, due to the balance of the strength of the demolding pins, the casting 1a being caught with respect to the main mold or the movable mold, etc., the casting 1a may be bent in the same manner as the bending generated in the heat treatment process ( Figure 2 Bending in the direction of arrow A shown).

[0035] In this embodiment, the machining reference hole 7 is formed in the bending direction ( Figure 2 Therefore, even if the bending described above occurs and the processing reference hole 7 and the recessed portion 8 are misaligned in the bending direction, when the jig 9 is inserted into the processing reference hole 7 ( Figure 4 ) When the casting 1a is machined (processing step) in a positioned state, the positioning jig 9 can be inserted into the processing reference hole 7, and the jig 9 can be brought into contact with the side walls 7b, 7b of the processing reference hole 7 in the width direction, so that the processing reference hole 7 can be reliably supported by the jig 9.

[0036] In addition, by providing a recessed portion 8 whose one end is connected to the machining reference hole 7 and whose other end is open to the outside of the top end of the vehicle body side arm 2b, even if water enters the machining reference hole 7 when the suspension arm 1 is mounted on the vehicle, the entering water can be drained by using the recessed portion 8. Moreover, the bottom 7a of the machining reference hole 7 and the bottom 8a of the recessed portion 8 are formed flush with each other and are formed in a manner that gradually tilts downward in the direction of gravity toward the top end side of the vehicle body side arm 2b, so that the entering water can be reliably drained. Moreover, water does not accumulate in the machining reference hole 7, so corrosion caused by water can be prevented, and the vehicle body side bearing portion 3 (other component connection portion of the present invention) will not be affected by corrosion.

[0037] Furthermore, since the machining reference hole 7 and the recessed portion 8 are formed by a core during casting, the machining reference hole 7 and the recessed portion 8 can be easily formed.

[0038] In the above-mentioned embodiment, the reference hole 7 and the recess 8 are formed by a core during casting. Figure 6 and Figure 7 As shown, the machining reference hole 10 can be formed by a core during casting, and then a recess can be formed by cutting by machining, and the recess can be cut so that one end is connected to the machining reference hole 10 and the other end is open to the outside. Figure 5The processing reference hole 7 including the imaginary line is formed in the same shape, and the diameter of the hole is formed longer in the bending direction than in the width direction of the vehicle body side arm portion 2b.

[0039] In addition, the vehicle support structure of the present invention is not limited to the suspension arm as in the above-mentioned example, but includes various components such as a steering knuckle that combines and supports various components such as a hub bearing and an arm, and various arm components that support the vertical movement of the steering knuckle and suppress the horizontal movement of the vehicle body.

Claims

1. A vehicle support structure, which is a vehicle support structure manufactured by casting, It is characterized in that The vehicle support structure has a machining reference hole formed during casting, the machining reference hole is formed to be longer in the direction of the bending generated in the molding process of the vehicle support structure, and the vehicle support structure has a recessed portion, one end of which is connected to the machining reference hole and the other end is open to the outside.

2. The vehicle support structure according to claim 1, It is characterized in that The bottom of the machining reference hole and the bottom of the recessed portion are gradually inclined downward in the gravity direction toward the other end side of the recessed portion.

3. The vehicle support structure according to claim 1 or 2, It is characterized in that The vehicle support structure is a suspension arm, and the machining reference hole is arranged on an upper surface of the suspension arm in a state in which the suspension arm is mounted on a vehicle and around a connection portion with another member.

4. A method for manufacturing a vehicle support structure, which is a method for manufacturing a vehicle support structure by casting, It is characterized in that The vehicle support structure is formed with a machining reference hole and a recessed portion during casting. The machining reference hole is elongated along a direction of curvature generated during the molding process of the vehicle support structure. One end of the recessed portion is connected to the machining reference hole and the other end is open to the outside.

5. The method for manufacturing a vehicle support structure according to claim 4, It is characterized in that The molding step includes a heat treatment step, and the direction in which the vehicle support structure is bent is the same as the direction in which the bending occurs during the heat treatment step.

6. The method for manufacturing a vehicle support structure according to claim 4, It is characterized in that The molding step includes a mold releasing step, and the direction in which the vehicle support structure is bent is the same as the direction in which the bending occurs during the mold releasing step.

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