JPH08155589A - Mold for suspension arm casting - Google Patents

Abstract

PURPOSE: To improve the dimensional precision and the casting surface precision at a casting step and to make the following work unnecessity, related to the shaft part and the shaft hole in a suspension arm as a casting product. CONSTITUTION: In a mold 1 for casting the suspension arm composed of a sand mold, a hollow cylindrical core 9 or 10 formed with a ceramic is arranged to a part directly used to the formation of the outer peripheral surface 8a of a pin 8 for connecting part with the parts at the other side and to a part directly used to the formation of the inner peripheral surface 7a of the same cylindrical part 7. The inner diameter of each core 9, 10 is matched to the outer diameter of the pin 8 and also, the outer diameter of each core 9, 10 is matched to the cylindrical part 7 and then, both cores 9, 10 are made to be commonly used to the formation of the pin 8 and the formation of the cylindrical part 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved mold for casting a cast iron suspension arm for an automobile by a sand casting method.

[0002]

2. Description of the Related Art A suspension arm for an automobile, which is made of sheet metal, which has hitherto been the mainstream, is replaced by cast iron, has been put into practical use in some parts. To manufacture this cast iron suspension arm, for example, after casting the suspension arm's overall shape by the sand mold casting method, the shaft part and shaft hole (bush mounting part) that will be the joint part with the mating part are machined. The finished product shape including the shaft part and the shaft hole described above can be formed accurately by a casting method using a mold. Has been.

[0003]

However, in the conventional method of manufacturing a suspension arm as described above, when casting is performed by the sand mold casting method, machining in the post-process is indispensable, so that the number of processing steps is reduced. In addition to increasing the number, the suspension arm itself has a complicated shape, making it difficult to chuck during machining such as turning. Therefore, a large cutting machine or a dedicated cutting machine is required, resulting in higher equipment costs. This is not desirable because it causes the result.

Further, when casting is performed by a casting method using a die, the number of machining steps in the subsequent process can be significantly reduced or eliminated, but the suspension arm itself has a complicated shape as described above. Therefore, it is necessary to take sufficient consideration such as improving the flowability of the molten metal in the casting method, and the die structure becomes complicated, which causes the cost of the entire equipment including the die to rise sharply as described above. .

The present invention has been made in view of the above problems, and the number of machining steps of the suspension arm in the subsequent process can be significantly reduced or eliminated by making a slight improvement in the sand casting mold. Therefore, it is an object of the present invention to provide a structure of a suspension arm casting mold that can reduce the facility cost and thus reduce the cost of the suspension arm.

[0006]

According to a first aspect of the present invention, a suspension arm made of cast iron having at least one of a shaft portion and a shaft hole which is a joint portion with a counterpart component is formed by a sand casting method. In the mold for casting,
It is characterized in that a cylindrical cylindrical core made of ceramics is arranged in a portion of the sand mold, which controls molding of the shaft portion or the shaft hole of the suspension arm.

According to a second aspect of the present invention, in the suspension arm casting mold according to the first aspect, the portion of the mold that controls the molding of the shaft portion of the suspension arm and the portion that controls the molding of the shaft hole are made of ceramic. The formed hollow cylindrical cores of the same size are individually arranged, and the outer diameter of the core is set to a size corresponding to the inner diameter of the shaft hole, and the inner diameter of the core is set to the shaft. The feature is that the size is set according to the outer diameter of the part.

[0008]

According to the structure of the first aspect, in the sand mold, the cylindrical portion made of ceramic is formed in the portion of the suspension arm that controls the molding of the shaft portion or the shaft hole which is the coupling portion with the counterpart component. Because it has a child,
For example, when a ceramic core is placed in the part that controls the molding of the shaft, the outer peripheral surface shape of the shaft part is a copy of the inner peripheral surface shape of the core, while molding the shaft hole. When the core made of ceramic is arranged in the controlled portion, the shape of the inner peripheral surface of the shaft hole is the shape of the outer peripheral surface of the core transferred. Therefore, the dimensional accuracy of the shaft portion or the shaft hole and the casting surface accuracy are significantly improved, and in any case, the dimensional accuracy of the shaft portion or the shaft hole and the casting surface accuracy can be improved by machining in the subsequent process. It can be finished with high precision at the casting stage to an unnecessary degree.

According to a second aspect of the present invention, a hollow cylindrical shape having the same size is formed of ceramic in a portion of the mold that controls the molding of the suspension arm shaft and a portion that controls the molding of the shaft hole. The cores are individually arranged, the outer diameter of the cores is set to a size that matches the inner diameter of the shaft hole, and the inner diameter of the cores is set to a size that matches the outer diameter of the shaft portion. Therefore, the intended purpose can be achieved by substantially using a common core for forming the shaft portion and the core for forming the shaft hole.

[0010]

1 to 6 are views showing an embodiment of the present invention, and particularly FIG. 3 is a plan view of only a lower mold. As shown in FIGS. 1, 2, and 4, 5 in addition to FIG. 3, a mold 1 made of a sand mold includes an upper mold 2 and a lower mold which are mutually matched at a mold matching surface 2a, 3a with a casting frame (not shown). The suspension arm 5, which is a casting, is cast by pouring the molten metal into the product part space 4 formed by the upper mold 2 and the lower mold 3.

The suspension arm 5 is formed integrally with the arm body 6 so that the tubular portion 7 serving as a connecting portion with a counterpart component and the pin 8 serving as a shaft portion are located on the same axis. A shaft of the mating side is inserted into and coupled to the cylindrical portion 7 through a mount rubber bush (not shown) with the inner peripheral surface 7a as a shaft hole.

In the present embodiment, in addition to FIG.
As shown in FIG. 2 and FIGS. 4, 5 and 6, a hollow cylindrical core 9 made of ceramic is preliminarily arranged in a portion of the mold 1 that controls the molding of the pin 8 and the same cylinder is used. A hollow cylindrical core 10 made of ceramic is arranged in advance in a portion of the shaped portion 7 that controls molding. These cores 9 and 10 are preset on the lower mold 3 side made of foundry sand and then matched with the upper mold 2. That is, as shown in FIGS. 1 and 2, one core 9 has an outer peripheral surface 8 of the pin 8.
a and the core 10 which is arranged so as to directly control the molding of the end surface 11a of the flange portion 11 adjacent thereto.
Are arranged so as to directly control the molding of the inner peripheral surface 7a of the tubular portion 7, as shown in FIGS.

The two cores 9 and 10 have the same size and common specifications, and the inner diameters of the cores 9 and 10 are required as the final product shape of the pin 8. The outer diameters of the cores 9 and 10 are set in accordance with the outer diameter of the pin 8, while the inner diameters of the inner peripheral surface 7a of the inner peripheral surface 7a of the cylindrical portion 7 required as the final product shape. Is set according to.

Therefore, according to the structure of this embodiment, as shown in FIGS. 1, 2, and 4, 5, 6, pouring is performed by a conventional method with both cores 9 and 10 set in the mold 1. The suspension arm 5 is cast by performing.

In this case, as shown in FIGS.
The outer peripheral surface 8a and the end surface 11a of the flange portion 11 adjacent to the pin 8 are formed by directly transferring the shape of one of the cores 9, and as shown in FIGS. The inner peripheral surface 7a of the portion 7 is formed by directly transferring the shape of the other core 10.

As a result, although the outer peripheral surface 8a of the pin 8 and the inner peripheral surface 7a of the tubular portion 7 are sand mold-cast,
The dimensional accuracy and the casting surface accuracy are significantly improved, and the outer peripheral surface 8a of the pin 8 and the inner peripheral surface 7a of the cylindrical portion 7 basically do not require machining such as cutting in a post process. Can be Moreover, since the cores 9 and 10 having the same size are used in common, the man-hours for manufacturing and managing the cores can be significantly reduced.

Here, in the above-mentioned embodiment, the cores 9 and 10 are arranged at the portion for molding the pin 8 and the portion for molding the tubular portion 7, respectively. However, if necessary, one of them may be made of ceramic. A well-known core made of cast sand may be adopted in place of the core 9 or 10 made of.

Further, in the above embodiment, the cores 9 and 10 have a common specification. However, depending on the outer diameter of the pin 8 and the inner diameter of the tubular portion 7, the cores may not have the common specifications. As such, separate cores are used for each pin 8 and tubular portion 7 in such cases. In such a case, the core that controls the molding of the inner peripheral surface 7a of the tubular portion 7 does not necessarily have to be hollow, and may be solid. The core for controlling the core does not necessarily have to have a circular outer peripheral surface, and may have a rectangular shape, for example.

[0019]

As described above, according to the first aspect of the present invention, in the sand mold, the molding of the shaft portion or the shaft hole of the suspension arm which requires relatively high dimensional accuracy and surface roughness accuracy. By arranging a cylindrical cylindrical core made of ceramics in the part that controls, since the dimensional accuracy and surface roughness accuracy are greatly improved for the molded part by transferring the core shape, Machining man-hours in the post-process for that portion can be significantly reduced or omitted. As a result, it is possible to significantly reduce the cost of the mold and thus the cost of the suspension arm that is the product.

In addition, as described above, since the relative positional accuracy between the shaft portion or the shaft hole and the arm body, which basically does not require post-processing, is determined at the same time as casting, post-processing is performed as in the conventional case. Compared with the case, there is an advantage that the relative positional accuracy between the shaft portion or the shaft hole and the arm body is further improved.

According to the second aspect of the present invention, the core for forming the shaft portion and the core for forming the shaft hole are made to have the same size, so that the core can be made common. The core man-hours and management man-hours can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention and is an enlarged sectional view taken along the line AA of FIG.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a view showing an embodiment of the present invention and is a plan view of only a lower mold forming a mold.

FIG. 4 is an enlarged cross-sectional view taken along the line CC of FIG.

5 is a cross-sectional view taken along the line D-D in FIG.

6 is an enlarged perspective view of a main part of the suspension arm shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mold 2 ... Upper mold 3 ... Lower mold 5 ... Suspension arm 6 ... Arm main body 7 ... Cylindrical part 7a ... Inner peripheral surface (shaft hole) 8 ... Pin (shaft part) 9, 10 ... Core

Claims (2)

[Claims] 1. A mold for casting a suspension arm made of cast iron having at least one of a shaft portion and a shaft hole, which is a joint portion with a mating component, by a sand mold casting method. A casting mold for a suspension arm, characterized in that a cylindrical cylindrical core made of ceramic is arranged in a shaft arm of the suspension arm or a portion that controls the molding of the shaft hole. 2. The suspension arm casting mold according to claim 1, wherein a hollow cylinder of the same size is formed of ceramic in a part of the mold that controls molding of the shaft part of the suspension arm and a part that controls molding of the shaft hole. -Shaped cores are individually arranged,
A suspension arm casting characterized in that the outer diameter of the core is set to a size matched to the inner diameter of the shaft hole, and the inner diameter of the core is set to a size matched to the outer diameter of the shaft portion. Mold.