JPH04274859A - Cooling method for casting die for wheel for vehicle - Google Patents

Abstract

PURPOSE:To offer the cooling method for a casting die which can cast efficiently a wheel having a rib on the inside surface without generating such a defect as a drawing defect, etc., on the outside surface. CONSTITUTION:A die 1 of the outside surface side of a wheel is water-cooled by a water-cooled pipe 10, and on the other hand, a rib forming part 13 of a die 2 of the inside surface side of the wheel is subjected to forced air cooling by an air passage 16 provided along this part. Water cooling has the better cooling performance than air cooling, therefore, a molten metal in a cavity 4 is solidified from the outside surface side, and such a defect as a drawing defect, etc., is not generated on the outside surface. when the inside surface side is solidified, the part of the rib is solidified without generating so much delay, compared with other part on the inside surface by forced air cooling, and the casting cycle time is shortened.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling a casting mold for low-pressure casting of vehicle wheels such as aluminum wheels.

0002

[Prior Art] Conventionally, as seen in Japanese Utility Model Application No. 63-6157 and Japanese Patent Application Laid-Open No. 2-151344, a mold consisting of a lower mold, an upper mold, and a divided mold around the lower mold is used. It is known that low-pressure casting of vehicle wheels is performed by injecting molten metal into a cavity in a mold using the gas pressure of
In this method, a water-cooling passage is formed in the lower die of the mold on the outer side of the wheel facing outward when mounted on the car body, and the lower die is water-cooled by the cooling water flowing through the passage, thereby accelerating the solidification of the outer side of the wheel. This prevents defects such as sink marks from occurring on the outer surface.

0003

By the way, when forming reinforcing ribs on the inner surface of the wheel, it is desirable to also cool the mold on the inner surface of the wheel in order to shorten the casting cycle time. If the molten metal on the inside side solidifies quickly, the unsolidified molten metal on the outside side will be drawn toward the inside side, causing sinkage on the outside side, so currently active cooling of the mold on the inside side is not done. Not yet.

[0004] In view of the above points, the present invention enables the mold on the inner side of the wheel to be actively cooled to shorten the casting cycle time, and the mold on the inner side and the outer side. The object of the present invention is to provide a method for cooling a wheel casting mold, which differs in cooling performance from that of the mold to prevent defects such as sink marks from occurring on the outer surface of the wheel.

[0005]

[Means for solving the problem] In order to achieve the above purpose,
In the present invention, when mounting on a vehicle body, the mold on the outer side of the wheel facing outward is water-cooled, and an air cooling passage is formed in the mold on the inner side of the wheel along the molded part of the rib formed on the inner side of the wheel. Then, the molded part was forced to air cool.

[0006]

[Operation] By forcing the rib molding part of the mold on the inner side of the wheel to cool with air, the solidification time of the ribs is shortened. On the other hand, the mold on the outer surface of the wheel that is water-cooled is cooled faster than the mold on the inner surface that is air-cooled, and the wheel solidifies from the outer surface, so that defects such as sink marks do not occur on the outer surface.

[0007]

[Embodiment] Fig. 1 shows a casting mold for a vehicle wheel, and the mold includes a lower mold 1, an upper mold 2 that can be raised and lowered, and both molds 1,
A cavity 4 that molds the disc part of the wheel between the upper mold 2 and the lower mold 1 by clamping the upper mold 2 as the upper mold 2 descends. , the upper and lower molds 1 are clamped by sliding the split mold 3 inward,
A cavity 5 for molding the rim portion of the wheel is formed between the mold 2 and the split mold 3. The split mold 3 is formed with a sprue 6 that communicates with the cavity 5 for the rim portion, and the lower mold 1
The molten aluminum in the molten metal holding furnace 7 provided on the lower side is supplied to the sprue 6 via the hot water supply pipe 8 and the runner 9 formed in the lower mold 1 by air pressure applied to the holding furnace 7. From step 6, molten metal was injected into the cavities 4 and 5 to perform low-pressure casting. In this embodiment, the outer surface of the wheel that faces outward when mounted on the vehicle body is molded with the lower mold 1.
A chiller 11 in which a water-cooled pipe 10 is cast is embedded in the lower mold 1, and the lower mold 1 is water-cooled by cooling water flowing through the water-cooled pipe 10. On the other hand, the upper mold 2 that molds the inner surface of the wheel has
A riser part 12 and a radial rib forming part 13 for forming ribs on the inner surface of the wheel are formed, and the upper mold 2
A cooling metal 15 having an annular air cooling pipe 14 cast therein is embedded therein, and radial air passages 16 are formed along each rib molded part 13 as shown in FIG. The air cooling pipe 14 and the outer end of the air passage 16 were connected to an annular exhaust pipe 17 fixed to the upper mold 2 through a connecting hole 15a formed in the chiller 15. According to this, the upper mold 2 is entirely air-cooled by the cooling air flowing through the air-cooled pipe 14 via the chiller 15, and the air-cooled pipe 1
4 to the exhaust pipe 17 via the air passage 16, the rib forming part 13 is efficiently air-cooled, and the solidification time of the molten metal in the rib part is shortened. However, air cooling has a lower cooling performance than water cooling, and therefore the molten metal in the cavity 4 solidifies from the lower die 1 side, that is, from the outer side of the wheel, and defects such as sink marks do not occur on the outer side. When the inner surface of the wheel solidifies, the rib portion also solidifies without much delay compared to other portions of the inner surface, and as a result, the casting cycle time is shortened.

Reference numeral 18 in the figure indicates an opening forming protrusion provided on the lower mold 1 to form an opening such as an air hole around the disk portion.

[0009]

Effects of the Invention As is clear from the above description, according to the present invention, the cooling performance of the mold on the outer side of the wheel and the mold on the inner side of the wheel are differentiated, so that the molten metal is cooled on the outside side. It has the effect of shortening the solidification time of the ribs on the inner side while satisfying the condition of solidifying from scratch, and efficiently casting high-quality wheels with no defects such as sink marks on the outer side.

[Brief explanation of the drawing]

[Fig. 1] Longitudinal cross-sectional view of a wheel casting mold to which the method of the present invention is applied

[Figure 2] Enlarged sectional view of the main parts

[Explanation of symbols]

1 Lower mold (outer side mold) 2 Upper mold (inner side mold)

Claims (1)

[Claims] Claim 1: A method for cooling a mold for casting a vehicle wheel, wherein the mold on the outer side of the wheel facing outward during mounting on a vehicle body is cooled with water, and the mold on the inner side of the wheel is cooled with water. 1. A method for cooling a mold for casting a vehicle wheel, comprising: forming an air cooling passage along a molded part of a rib formed on a side surface, and cooling the molded part with forced air.