JPH08243723A - Low pressure casting device for wheel for vehicle - Google Patents

Abstract

PURPOSE: To produce a wheel for vehicle providing perfect directional solidification by working a second cooling means after working a first cooling means. CONSTITUTION: Molten metal pressure is risen at a fixed pressurizing rate and pushed up to the top part of a molten metal supplying pipe 70. Thereafter, the pressurization is executed in a necessary time in the condition of lowering the pressurizing rate. Cooling water is started to flow into the first cooling passage 81 after elapsing e.g. 5sec since this point of time, and a mold temp. is detected with a cooling control means, and the cooling water is continued to flow till becoming the set mold temp. Thereafter, the pressurization is executed for e.g. 10sec in the condition of rising the pressurizing rate, and the molten metal pressure is risen. Thereafter, the pressurization is executed for e.g. 5sec in the condition of lowering the pressurizing rate, and the molten metal pressure is risen. Then, the pressure holding condition is continued till passing the arbitrary time. At this time, the cooling water is started to flow in the second cooling passage 82 and the mold temp. is detected with the cooling control means, and the cooling water is continued to flow till becoming the set mold temp.

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 device for a vehicle wheel, and more particularly to a cooling means for parts constituting a disk molding portion and a spoke molding portion in a mold.

[0002]

2. Description of the Related Art A conventional low pressure casting apparatus of this type is
An annular cooling means is doubly installed in the parts forming the disk molding part and the spoke molding part in the mold to cool these parts.

[0003]

However, in such a conventional low-pressure casting apparatus, since the double annular cooling means are simultaneously actuated, that is, the simultaneous cooling is performed, the radial direction from the disk portion is increased. However, there was a disadvantage that a sufficient directional solidification could not be obtained. An object of the present invention is to eliminate such inconvenience.

[0004]

In order to achieve the above object, in a low-pressure casting apparatus for a vehicle wheel according to the present invention, the mold includes a disk molding portion, a spoke molding portion, and a rim molding portion. A weir is provided in the portion forming the rim-forming portion, and the second cooling means is provided in the portion forming the spoke-forming portion in the mold while installing the first cooling means in the portion forming the disk-forming portion in the mold. In a low-pressure casting apparatus for a vehicle wheel, which is installed and includes cooling control means for controlling these cooling means, the cooling control means operates the second cooling means after activating the first cooling means. It was made to let.

[0005]

Since the low-pressure casting device for a vehicle wheel according to the present invention is configured as described above, the molten metal filled in the cavity is cooled radially from the disk portion to the spoke portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a low pressure casting device for a vehicle wheel, and FIG. 2 is a control diagram of a cooling means.

In FIG. 1, reference numeral 10 is a base of the casting apparatus D. The base 10 supports a mold set S for molding a vehicle wheel. This mold set S is a lower mold
It is a combination of 20 and a pair of horizontal molds 30,30 and an upper mold 40.
50 is a cavity, which is formed by the mold set S. This cavity 50 is in the shape of a wheel for a vehicle, and is composed of a disk molding portion 51, a spoke molding portion 52, and a rim molding portion 53. Reference numeral 21 is a nest of the lower die 20 for molding the surface of the disk portion (of the vehicle wheel).

Reference numeral 60 denotes a molten metal holding furnace, which is arranged below the base 10. The molten metal M is accommodated in the molten metal holding furnace 60. Also, 70 and 70 are molten metal supply pipes,
It is installed almost vertically on 10. This molten metal supply pipe 70,7
The lower end of 0 opens into the molten metal holding furnace 60. The molten metal M in the molten metal holding furnace 60 is pressurized so that the molten metal replenishing pipes 70, 70 are raised and filled in the cavity 50. The flow path from the molten metal supply pipe 70 to the cavity 50 will be described later.

Reference numerals 31 and 31 are flow passage changing runners, and the horizontal type 30
Is formed. The runners 31, 31 are substantially L-shaped, and one end of the runners 31 is opened to the rim molding portion 53 of the cavity 50.
It constitutes weirs 311 and 311. Also, the flow path changing runner 3
The other end of 1,31 communicates with the upper end opening of the molten metal supply pipe 70,70. Therefore, the molten metal M that has risen in the molten metal supply pipes 70, 70 is supplied to the rim forming portion 53 of the cavity 50 via the flow path changing runways 31, 31 of the horizontal molds 30, 30. In addition, 302 is a horizontal type 3
It is a parting surface of 0,30.

Reference numeral 81 denotes an annular first cooling passage (corresponding to the "first cooling means" of the present invention), which is formed in the insert 21 of the lower mold 20. Reference numeral 82 denotes an annular second cooling passage (corresponding to the "second cooling means" of the present invention), and the lower mold 20
Is formed. The second cooling passage 82 surrounds <br/> the first cooling passage 81. Cooling water flows through these cooling paths 81, 82.

Further, 90, 90 are cooling pipes, which are arranged on the back side of the upper mold 40. These cooling pipes 90, 90 cool the upper mold 40 by blowing cooling air from the tip nozzle onto the back surface of the upper mold 40.

Next, a method of controlling these cooling means will be described with reference to FIG.

First, the molten metal pressure is raised to 0.230 over a period of 13 seconds at a constant pressurizing rate (pressurizing gradient) to push the molten metal to the top of the molten metal supply pipe 70.

Thereafter, pressure is applied for a required time (16 to 25 seconds) with the pressure ratio (pressurization gradient) being lower than that in the previous pressurization. The time required at this time is changed according to the diameter of the wheel and the rim width. That is, the required time increases as the volume of the molten metal increases. After 5 seconds from this point, the cooling water starts to flow into the first cooling passage 81, the mold temperature is detected by the cooling control means C, and the cooling water continues to flow until the set mold temperature is reached. At the same time, spot cooling is started in the local heating section and stopped before the end of the pressure holding state.

After that, the pressurizing rate (pressurizing gradient) is increased for 10 seconds while the pressurizing rate is higher than that in the previous pressurization, and the molten metal pressure is 0.500.
Up to.

After that, the pressurizing ratio (pressurizing gradient) is lowered for 5 seconds with the pressurizing ratio being kept lower than that in the previous pressurization, and the melt pressure is set to 0.530.
Up to. Then, the pressure holding state is continued until an arbitrary time passes. At this time, the cooling water is started to flow into the second cooling passage 82, the mold temperature is detected by the cooling control means C, and the cooling water is kept flowing until the set mold temperature is reached. At the same time, during the pressure-holding state, the cooling pipe 90 cools the front of the weir of the upper mold 40 with air.

After that, the molten metal pressure is reduced at a constant reduced pressure ratio (pressure reduction gradient) to zero. At this time, decompression starts 10
Continue to air cool the weir from seconds before the mold opens. Note that the above-mentioned numerical values are examples, and change depending on the length of the molten metal supply pipe 70 and the amount of molten metal. That is, the molten metal in the holding furnace 60 decreases,
If the distance to the head of the molten metal supply pipe 70 becomes longer, the pressurizing pressure needs to be corrected (increased). Further, when the product becomes large and the molten metal amount increases, the pressurizing time and the cooling time become long.

[0018]

In the low-pressure casting apparatus for a vehicle wheel according to the present invention, the mold includes a disk molding portion, a spoke molding portion, and a rim molding portion, and a weir is provided in a portion constituting the rim molding portion of the mold. Further, the first cooling means is installed in a portion of the mold forming the disk molding portion, and the second cooling means is installed in a portion of the mold forming the spoke molding portion, and cooling for controlling these cooling means. In the low-pressure casting apparatus for a vehicle wheel having a control means, the cooling control means activates the first cooling means and then activates the second cooling means. It is cooled radially from the part toward the spoke part.

Therefore, if this low-pressure casting device for a vehicle wheel is used, the above-mentioned directional solidification more complete than that in the conventional case (directional solidification radiating from the disc portion to the spoke portion in a radial direction).
It is possible to cast a vehicle wheel provided with.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a low pressure casting device for a vehicle wheel.

FIG. 2 is a control diagram of a cooling unit.

[Explanation of symbols]

20… Lower mold (portion forming spoke forming part of mold) 21… Nesting (portion forming disk forming part of mold) 30… Horizontal type (portion forming rim forming part of mold) 31… Weir 51… disc Molding part 52… Spoke molding part 53… Rim molding part 81… First cooling path (first cooling means) 82… Second cooling path (second cooling means) C… Cooling control means S… Mold set (mold)

Claims (1)

[Claims] 1. A mold includes a disk molding portion, a spoke molding portion, and a rim molding portion, a weir is provided in a portion forming the rim molding portion of the mold, and a portion forming the disc molding portion in the mold. In a low-pressure casting device for a vehicle wheel, which is provided with a first cooling means, a second cooling means is installed in a portion forming a spoke molding portion in the mold, and a cooling control means for controlling these cooling means is provided. The low-pressure casting device for a vehicle wheel, wherein the cooling control means activates the second cooling means after activating the first cooling means.