JPS63203263A - Light metal alloy casting - Google Patents

Abstract

PURPOSE:To use casting without taking out core, to freely produce shape of the core, to hold rigidity even in thin thickness and to enable further lightening by forming the core for hollow part of light alloy casting by foaming aluminum. CONSTITUTION:Part of rim 1 and part of hub 2 are integrately formed as casting by spokes 3. A shaft hole core 6 made of sand core is set in an outer die 5 and further, the core made of the foaming aluminum is set at the spoke part 3. And the light alloy casting is poured and after cooling, the light alloy casting is taken out and a sprue is removed and the shaft hole core 6 is crushed to remove. As the core 7 made of the foaming aluminum has little thermal capacity, high heat insulating, light weight, good machinability and good permeability, blow hole in the light alloy casting is scarcely developed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to light alloy castings used for vehicle parts and the like.

[Conventional technology and its problems]

In vehicles such as motorcycles, wheels, frame parts, hawk parts, etc. made of light alloy castings are used to reduce the weight of the vehicle and improve vehicle performance.

Moreover, in order to further reduce weight while maintaining rigidity,
A hollow part is provided using a core. For example, Jitsukai Showa 6
See Publication No. 0-139501. To create a hollow part in a light alloy casting, generally, a core is made from shell malt, etc., this core is cast in a light alloy casting, and after it cools and hardens, the core is crushed and passed through a small hole, and the core is sanded. The core is removed and washed, leaving a hollow core. Since core sand has a large heat capacity, IS construction is difficult unless the wall thickness of the hollow part is at least 4cm or more. In addition, the shape of the core is limited due to the need to remove sand from the core, and there is a limit to maintaining rigidity due to the thin wall thickness, and the sand removal process is time-consuming and inconveniently increases manufacturing costs. [Objective of the Invention] This invention forms the core of the hollow part of a light alloy casting with foamed aluminum, can be used without removing the core, can be freely shaped, and has a thin wall that maintains rigidity. The purpose of the present invention is to obtain a light alloy casting that can be further reduced in weight, has good work efficiency, and can reduce costs.

[Structure of the invention]

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

1 and 2 show examples of light alloy casting wheels for motorcycles. A part of a rim 1 on which a tire is mounted and a part of a hub 2 through which an axle is passed are integrally cast by a plurality of spokes 3. The hub 2 has an axle hole 4 in the center through which the axle passes.
Conventionally, the spokes 3 are formed hollow using a core to reduce weight. In the present application, as shown in FIG. 2, a shaft hole core 6 made of a sand core is set inside the outer mold 5, and further, a shaft hole core 6 made of a sand core is set in the spoke 3 portion.
Set the aluminum foam core 7.

Then, the light alloy casting is poured. After cooling down, take out the light alloy casting in the shape of a wheel, remove the sprue, and insert the shaft hole core 6.
Crush and remove. The foamed aluminum core 7 is used as it is in a light alloy casting.

[Action of the invention]

Since the foamed aluminum core 7 has a small heat capacity, high heat insulation properties, and good wettability with molten aluminum, the thickness of the light alloy casting of the spoke 3 portion can be made thinner, and further weight reduction can be achieved. Since the aluminum foam core 7 does not need to be taken out, the work can be omitted and costs can be reduced. Since the foamed aluminum core 7 has a volume ratio of 1/10 of the weight of the light alloy casting, there is only a slight increase in weight even if it is not removed, and the weight can be reduced by reducing the wall thickness of the light alloy casting. . Furthermore, foamed aluminum has good workability and can be formed into complex shapes. The foamed aluminum core 7 has good air permeability and is less likely to form cavities during casting of light alloy castings.

[Other Examples]

Figure 3 shows a motorcycle frame, in which front and rear frame fittings 8.9 made of light alloy castings are welded together with light alloy pipes 10, and in this case, foamed aluminum cores 11.12 are also used. Can be cast to reduce weight.

FIG. 4 shows the case of a rear fork. When the fork fitting 13 is made of light alloy casting, a foamed aluminum core 14 is cast inside to reduce the weight.

〔Effect of the invention〕

As explained above, in this invention, a foamed aluminum core is cast into a light alloy casting, and a product is made with the foamed aluminum core still cast, so there is no need to remove the foamed aluminum core. can be omitted, reducing costs. And the foamed aluminum core is lightweight,
It has good wettability with light alloy castings and can be made thinner, making it possible to reduce weight while maintaining rigidity. Further, since the foamed aluminum core has good workability and does not need to be taken out, it may have a complex shape. Furthermore, when the edge of the foamed aluminum core protrudes, and when cutting the outer diameter of a light alloy casting, etc., the cutting can be done simultaneously and the cutting teeth will not be damaged.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a front view, FIG. 2 is a longitudinal sectional view showing the casting situation, and FIG. 3 is a side view showing another embodiment of the invention. FIG. 4 is a plan view showing another embodiment of the present invention. 1.2.3.8.9.13...Light alloy casting, 7.11
．． 12.14... Core of foamed aluminum.

Claims (1)

[Claims] A light alloy casting characterized by casting a foamed aluminum core in a light alloy casting and producing a product with the foamed aluminum core still cast.