JPH05269563A - Low pressure casting method for light alloy wheel for vehicle - Google Patents

Abstract

PURPOSE:To reduce the casting defect and to lighten a light alloy casting wheel. CONSTITUTION:In this low pressure casting method for wheel, molten metal is poured into a die 48 by arranging one pouring hole 50 at the center part of a disk and two or more pouring holes 52 at the rim end. By arranging cooling devices 54 surrounding the pouring holes 50, 52 in the die, the solidified speed of the molten metal at the pouring hole positions may be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure casting method for a light alloy wheel for a vehicle, which is capable of suppressing casting defects and reducing the wall thickness.

[0002]

2. Description of the Related Art As a low pressure casting method for casting aluminum wheels, there are the following methods. (1) A method in which one pouring port is provided in the center of the disc, and pouring is performed from there to the disc and rim. (2) A method in which at least one pouring port is provided at the rim end, and pouring is performed from there to the rim and the disc.

[0003]

[Problems to be Solved by the Invention] In order to reduce the weight of an aluminum wheel, it is necessary to reduce the wall thickness of a casting.
The above conventional method has the following problems. (1) When the molten metal is poured from the center of the disc, as shown in FIG. 3, the rim portion 2 and the connecting portion 6 between the disc 4 and the rim 2 are formed.
In addition, shrinkage cavities are likely to occur. (2) When the molten metal is poured from the rim end, shrinkage cavities and defective running around the hub hole 8 and the mounting surface 10 occur.

In order to eliminate the above casting defects,
In the conventional method, in FIG. 3, the disk portion 4 and the reinforcing rib 1 are
It is usual to take measures such as increasing the thickness of 2 and increasing the number of reinforcing ribs 12. However, all of these measures increase the casting weight and hence the product weight,
It is no longer in line with weight reduction of vehicles.

An object of the present invention is to provide a low pressure casting method for a light alloy wheel for a vehicle, which can suppress the occurrence of casting defects and can contribute to the weight reduction of castings.

[0006]

According to the present invention, the above object is achieved by the following low pressure casting method for a light alloy wheel for a vehicle. (1) A low-pressure casting method for a light alloy wheel for a vehicle, in which one pouring hole is provided at the center of the disk and two or more pouring holes are provided at the rim end.

(2) The low pressure casting method for a light alloy wheel for a vehicle according to the above (1), in which a mold cooling device is provided around each pouring port to control the rate of solidification of the molten metal at the pouring port.

[0008]

In the low pressure casting method for a light alloy wheel for a vehicle according to the above method, since the pouring port is provided at the center of the disc and the rim end, the disc is mainly poured from the pouring port at the center of the disc, Is mainly poured from the pouring port at the edge of the rim, which makes it possible to improve the hot water flow and suppress casting defects due to poor hot water flow.

Further, by providing a mold cooling device around each pouring port and controlling the rate of solidification of the molten metal at the pouring port, the occurrence of shrinkage cavities can be suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a low pressure casting method for a light alloy wheel for a vehicle according to the present invention will be described below with reference to FIGS. However, FIG. 1 relates to the first embodiment, and FIG.
Relates to the second embodiment.

First, the first embodiment will be described. In FIG. 1, a light alloy (for example, aluminum or aluminum alloy) wheel 20 to be cast is a cast wheel in which a rim portion 22 and a disc portion 24 are integrated. The rim portion 22 is an annular body, the disc portion 24 is a dish-shaped body, a tire is mounted on the rim portion 22, and the disc portion 24 is attached to the axle shaft of the vehicle.

The rim portion 22 has a flange portion 26, a bead seat portion 28, a well portion 30, a bead seat portion 32, and a flange portion 34 in this order from the end opposite to the disc portion 24. Especially, the flange portions 26 and 34, the bead seat portion 2
Since the parts 8 and 32 receive a large load from the tire, it is not desirable that the parts have casting defects.

An outer peripheral portion of the disc portion 24 is integrated with the rim portion 22, and a hub hole for attachment to a vehicle axle shaft is formed in the center portion 36 by machining after casting. Further, around the hub hole, bolt holes for attaching hub bolts are formed at equal intervals in the circumferential direction by machining after casting. Further, 38 is a reinforcing rib and 40 is a hole for a decorative window, which are provided at the casting stage.

In manufacturing the above-mentioned wheel by the low pressure casting method, a die 48 composed of an upper die 42, a lower die 44, a horizontal die 46, etc. is provided with a disk portion when the wheel is cast as shown in FIG. Set so that 24 is at the bottom and the wheel axis is vertical. Then, in a space inside the mold 48, a molten metal tank (not shown) provided below the mold 48 applies a low pressure to the molten metal surface to push up the molten metal, and the molten metal is poured through the Stokes and the pouring port. After the molten metal in the mold 48 solidifies for a predetermined time after pouring, the mold 48 is disassembled and the casting wheel is taken out of the mold 48. After the wheels have cooled, the wheels are machined, such as with hub holes and bolt holes.

The method of the present invention is different from the conventional method in that the mold 48 is used.
The molten metal pouring port into the inner space is composed of one pouring port 50 provided at the center of the disc and two or more pouring ports 52 provided at the rim end. These two types of pouring ports 50, 5
It is the point of pouring at the same time through 2. Rim edge pouring spout 5
2 are provided at equal intervals in the circumferential direction at the rim end near the disc portion 24.

The pouring port 50 at the center of the disc portion is a pouring port mainly for pouring the disc portion 24, and the pouring port 52 at the rim end is a pouring port for mainly pouring the rim portion 22. The size of the pouring port 50 and the size and number of the pouring ports 52 are changed depending on the size and design of the wheel (where the decorative window holes and ribs are, etc.).

The casting method of the first embodiment has the following actions and effects. A pouring port 50 for pouring the disc portion 24
Since the pouring port 52 for pouring the molten metal into the rim portion 22 is divided, compared with the conventional case where the pouring port is provided only at either the center of the disc portion or the end of the rim, the molten metal is poured into the mold 48. The distance flowing inside becomes shorter, the temperature drop of the molten metal is less, the flow of the molten metal is better, and casting defects are less than in the conventional method.

Further, the thickness of the casting can be reduced by the amount of the improved flow of the molten metal, and for example, the thickness of the rim well portion 30 and the disk portion 24, which have a sufficient strength, can be thinned without causing the defective spinning. The weight of the wheels is reduced, which contributes to the weight reduction of vehicles and the improvement of fuel efficiency.

Further, the solidification rate of the molten metal in the mold 48 is increased by the amount that the thickness of the casting can be reduced, the mechanical properties of the casting are improved, and the casting cycle time can be shortened.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, in addition to the method of the first embodiment, a mold cooling device 54 is provided around each of the pouring ports 50 and 52.
Is provided to control the solidification rate of the molten metal at the pouring ports 50, 52. The cooling device 54 is provided with cooling gas pipes or cooling water pipes near the pouring ports 50 and 52 of the mold 48 for cooling.

By doing so, in the second embodiment, it is possible to further improve the casting quality and reduce the casting cycle time while maintaining all the actions and effects of the method of the first embodiment. .

[0022]

According to the present invention, the following effects are obtained. (1) According to the method of claim 1, since one pouring port is provided at the center of the disc and two or more pouring ports are provided at the rim end to pour the metal into the mold, the hot water flow is good and casting defects It is possible to suppress the occurrence of heat generation and to reduce the thickness of the casting, and also to reduce the weight.

(2) According to the method of claim 2, since the molten metal solidification rate at the pouring port is controlled, the quality of the casting is further improved and the casting cycle is maintained while maintaining the effect of the method of claim 1. It is possible to reduce the time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the vicinity of a casting wheel in a state where a low pressure casting method for a vehicle light alloy wheel according to a first embodiment of the present invention is being performed.

FIG. 2 is a cross-sectional view of the vicinity of a casting wheel in a state in which a low pressure casting method for a light alloy wheel for a vehicle according to a second embodiment of the present invention is being performed.

FIG. 3 is a cross-sectional view of the vicinity of a casting wheel in a state where a low pressure casting method for a conventional light alloy wheel for a vehicle is being performed.

[Explanation of symbols]

 20 Light Alloy Wheel 22 Rim Part 24 Disk Part 48 Mold 50 Pouring Port 52 (Provided at Center of Disc) 52 Pouring Port (Provided at End of Rim) 54 Cooling Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Koji Yagi, 5 Yonbancho, Chiyoda-ku, Tokyo, 9 Topy Industries Co., Ltd. Within the corporation

Claims (2)

[Claims] 1. A low-pressure casting method for a light alloy wheel for a vehicle, comprising: providing one pouring port at the center of the disc and two or more pouring ports at the rim end to pour into the mold. 2. The low-pressure casting method for a light alloy wheel for a vehicle according to claim 1, wherein a cooling device for the mold is provided around each of the pouring ports to control the rate of solidification of the molten metal at the pouring ports.