CASTING METHOD AND CASTING DEVICE

• US 20180178276A1
• Filed: 03/04/2015
• Published: 06/28/2018
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: MASUTA, Tatsuya, OTA, Shunsuke
• Granted Patent: US 10,441,998 B2
• Time in Patent Office: Days
• CPC Class Codes: B22D 18/04 Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould
• CPC Class Codes: B22D 18/08 Controlling, supervising, e.g. for safety reasons controlling or regulating in general G05

Abstract

Molten metal M is raised to the vicinity of a gate 11 of a cavity 9C by increasing the pressure in a holding furnace 5 with gas, and thereafter the cavity 9C is filled with the molten metal M by decreasing the pressure in the cavity 9C by suction and further increasing the pressure in the holding furnace 5. Thereafter, the decompression of the cavity 9C is stopped after a preset filling time, and the compression of the holding furnace 5 is stopped when solidification of the molten metal M is completed. In this way, the suction is minimized, and it becomes possible to employ a simple decompression part 14. A reduction in equipment cost and production cost is thereby achieved, and a reduction in casting cycle time is also achieved.

Claims

1. A casting method for molding a product based on low-pressure casting by using a casting device in which a mold with a cavity is disposed over a holding furnace storing molten metal, comprising a step of:

raising the molten metal to a vicinity of a gate of the cavity by increasing a pressure in the holding furnace and thereafter filling the cavity with the molten metal by decreasing a pressure in the cavity by suction and further increasing the pressure in the holding furnace.

3. The casting method according to claim 1, further comprising steps of:

using a molten metal sensor for detecting completion of filling the cavity with the molten metal; and

stopping decompression of the cavity when the molten metal sensor detects the completion of filling with the molten metal within the preset filling time.

4. A casting device to which the casting method of claim 1 is applicable, comprising:

a plurality of casting units, each comprising a holding furnace configured to store molten metal, a mold with a cavity and a compression part to increase a pressure in the holding furnace; and

a decompression part to decrease a pressure in cavity of each of the plurality of casting units by suction,

wherein the decompression part comprises a vacuum tank with a suction pipe at an inlet side and a discharge pipe at an outlet side, a vacuum pump connected to the discharge pipe of the vacuum tank, branch pipes that are branched from the suction pipe of the vacuum tank and are respectively communicated with the cavity of each of the plurality of casting units and on-off valves configured to open and close the respective branch pipes.

5. The casting device according to claim 4, wherein the cavity of the mold is a casting space for molding a suspension member of a car.

6. The casting device according to claim 4, wherein the cavity of the mold is a casting space for molding a cylinder head of an internal combustion engine.

7. The casting device according to claim 4, wherein the cavity of the mold is a casting space for molding a motor case.

2. A casting method for molding a product based on low-pressure casting by using a casting device in which a mold with a cavity is disposed over a holding furnace storing molten metal, comprising steps of:

raising the molten metal to a vicinity of a gate of the cavity by increasing a pressure in the holding furnace and thereafter filling the cavity with the molten metal by decreasing a pressure in the cavity by suction and further increasing the pressure in the holding furnace;

stopping decompression of the cavity after a preset filling time; and

stopping compression of the holding furnace when solidification of the molten metal is completed.

8. The casting method according to claim 2, further comprising steps of:

using a molten metal sensor for detecting completion of filling the cavity with the molten metal; and

stopping decompression of the cavity when the molten metal sensor detects the completion of filling with the molten metal within the preset filling time.

9. A casting device to which the casting method of claim 2 is applicable, comprising:

a plurality of casting units, each comprising a holding furnace configured to store molten metal, a mold with a cavity and a compression part to increase a pressure in the holding furnace; and

a decompression part to decrease a pressure in cavity of each of the plurality of casting units by suction,

wherein the decompression part comprises a vacuum tank with a suction pipe at an inlet side and a discharge pipe at an outlet side, a vacuum pump connected to the discharge pipe of the vacuum tank, branch pipes that are branched from the suction pipe of the vacuum tank and are respectively communicated with the cavity of each of the plurality of casting units and on-off valves configured to open and close the respective branch pipes.