JP3212208B2 - Low pressure casting machine for cage rotor - Google Patents

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 apparatus for a cage rotor using pure aluminum or an aluminum alloy containing silicon or the like.

[0002]

2. Description of the Related Art A method of forming a conductor of a cage rotor is roughly classified into a die having a smaller outer diameter, a die casting method, a low pressure casting method (a low pressure die casting method), and a copper or copper alloy groove. There is a brazing method of brazing a short-circuit ring to a conductor bar. Die casting is applied to small cage rotors using pure aluminum (approximately 99.7%), which has relatively good electrical conductivity, and has a margin of electrical properties, electrical dimensions and mechanical strength. Yes, and because it is mass-produced, capital investment is easy. In the die casting method, the outer diameter of the rotor is almost limited to a range of 200 to 300 φ. Rotating electric machines with an outer diameter of 300 to 500φ in the outer diameter of the rotor are produced in a relatively large variety and in small quantities, and low pressure casting can be applied using pure aluminum for the conductor. There is no material defect and the quality is better than when applied.

FIG. 2 is a longitudinal sectional view of a conventional example. In the figure, a stalk 3 is immersed in a holding furnace 2 having an air port 2a and a lid 2b that can store a molten metal 1 so as to be refillable and that is near the bottom. At the upper end of the stalk 3, it is separable up and down and the top 4a
Pool 4 having a liquid junction is liquid-tightly joined. The lower mold 5 includes a mold gate 5b that can communicate with the upper gate 4a, and a cavity 5a for a lower short-circuit ring. The intermediate mold 6 has a shaft 6a
Is provided around the outer periphery of the laminated core 7 with a cavity 7a for a groove for a conductor provided in the periphery. The upper die 8 includes a cavity 8a for an upper short-circuit ring and a cavity 8b for a blade. The pool 4, the lower mold 5, the intermediate mold 6, and the upper mold 8 can be separated from each other at the joint surface.

A laminated iron core 7 having a shaft 6a inserted into a shaft center is mounted in a lower die 5, an intermediate die 6 and an upper die 8, and the entire die is appropriately preheated to be liquid-tight in the water pool portion 4. After joining, the gas pressure of air or the like (about 0.05 to 0.1 atm) is applied to the air port 2a.
When the molten metal 1 is pressurized from above, the molten metal 1 rises up the stalk 3, passes through the pool 4, the upper pouring gate 4 a, and the mold pouring gate 5 b, passes through the lower short-circuit ring cavity 5 a, the groove cavity 7 a, and the upper short-circuit ring cavity 8 a , And sequentially rises with the blade cavities 8b to fill the entire cavities. When the molten metal in the cavity solidifies, the lower mold 5 is separated from the pool 4 by separating the conductive metal between the upper gate 4a and the mold gate 5b.
Thereafter, if the lower die 5, the intermediate die 6, and the upper die 8 are separated, a cage rotor having the groove conductor, the short-circuit ring, and the blade can be taken out from the inside. The lower mold 5 is separated before the molten metal in the pool 4 having a sufficient volume solidifies.

[0005]

In the prior art, the molten metal in the cavity progresses directional solidification from the upper part to the lower part in the mold sequentially and solidifies, and finally solidifies (the liquid phase and the solid phase). If the lower mold 5 is separated from the pool 4 when the boundary is located between the upper gate 4a and the mold gate 5b, the mold can be easily separated. However, it is practically difficult to judge such timing and situation, and therefore, the defective product in which the lower short-circuiting ring is not formed yet because the lower short-circuiting ring cavity 5a is still separated in the liquid phase. It is very difficult to separate the lower mold 5 from the pool 4 by removing the lower mold 5 from the pool 4 after the upper portion of the pool 4 becomes a solid phase. Water pool 4
Must be scraped out of the upper solid phase part, and continuous casting cannot be performed. In addition, when preparation time is required for changing the mold type (the size of the cage rotor is different), the molten metal in the pool 4 or the stalk 3 is dropped into the holding furnace 2 once, and then the operation is started again. Must be started and continuous casting is not possible.

An object of the present invention is to make sure that the final solidification part (boundary between the liquid phase and the solid phase) in the mold is always located between the upper gate and the lower mold gate of the pool. It is another object of the present invention to provide a low-pressure casting apparatus for a cage rotor which can easily separate a lower mold from a pool in any time.

[0007]

According to the first aspect of the present invention, there is provided a low pressure casting apparatus for a cage rotor, in which a basin having an upper sprue is provided at an upper end of a stalk immersed near the bottom of a holding furnace capable of storing and pressurizing a molten metal. The lower mold is provided with a mold gate that can communicate with the upper gate and a cavity for a lower short-circuit ring, and the intermediate mold has a cavity for a conductor groove around the shaft inserted into the shaft center. The upper mold has a cavity for the upper short-circuit ring, and the cage has a cage-shaped rotation that allows the pool, lower mold, intermediate mold and upper mold to be separated from each other at the joint surface. In a low pressure casting apparatus for a child, a gate heating means is provided at an upper gate of a pool.

The low pressure casting apparatus for a cage rotor according to the second aspect of the present invention includes:
At the upper end of the stalk where the molten metal is stored and immersed close to the bottom of the holding furnace that can be pressurized, the pool with the upper sprue is joined to
The lower mold has a mold gate that can communicate with the upper gate and a cavity for the lower short-circuit ring, and the intermediate mold has a cavity for inserting a shaft at the shaft center and a cavity for a conductor groove around the shaft. Surrounding the outer circumference of the iron core, the upper mold has a cavity for the upper short circuit ring, and the low pressure of the cage rotor allows the pool, lower mold, intermediate mold and upper mold to be separated from each other at the joint surface. In the casting apparatus, a basin heating means is provided in the basin section.

[0009]

According to the invention 1 or 2, even if the molten metal in the cavity is solidified, the vicinity of the upper sprue is heated by the sprue heating means or the puddle heating means. Will be continuously present in the vicinity between. Therefore, the lower mold can be easily separated from the pool at any time, the cavity for the lower short-circuit ring has been solidified, and the pool and the inside of the upper gate remain molten.

[0010]

FIG. 1 is a longitudinal sectional view of an embodiment. In the prior art and in each drawing, components having the same reference numerals have approximately the same functions, and such portions will be described first. In the figure,
A stalk 3 is immersed in a holding furnace 2 having an air port 2a and a lid 2b which can store the molten metal 1 so that it can be replenished and which is near the bottom.
A basin part 4 having a top gate 4a which can be separated vertically and is liquid-tightly joined to the upper end of the stalk 3. The lower mold 5 includes a mold gate 5b that can communicate with the upper gate 4a, and a cavity 5a for a lower short-circuit ring. The intermediate mold 6 surrounds the outer periphery of the laminated core 7 with a shaft 6a inserted in the shaft center and a cavity 7a for a groove for a conductor provided around the shaft 6a. The upper die 8 includes a cavity 8a for an upper short-circuit ring and a cavity 8b for a blade. The pool 4, the lower mold 5, the intermediate mold 6, and the upper mold 8 can be separated from each other at the joint surface.

As a feature of the embodiment, the sluice heating means 11 is provided at the upper sluice 4a of the sluice part 4, and the sluice heating means 12 is provided at the basin part 4. As the gate heating means 11 and the pool heating means 12, an induction heater, a resistance heater, a combustion burner heater, or the like can be used.

According to such a structure, when the entire mold is appropriately preheated and joined to the pool 4 and gas pressure is applied,
The molten metal 1 rises up the stalk 3, and the pool 4, the top 4
a, via the mold gate 5b, the cavity 5 of the lower short-circuit ring
a, groove cavity 7a, upper short ring cavity 8
a, the cavities 8b of the blades are sequentially raised to fill all the cavities. Even if the molten metal in the cavity is solidified, the upper gate 4a is heated by the gate heating means 11 and the pool 4 is heated by the pool heating means 12, so that the final solidification part (the boundary between the liquid phase and the solid phase) ) Is upper gate 4a and mold gate 5a
Will be continuously present in the vicinity between. Therefore, the lower mold 5 can be easily separated from the pool 4 at any time, the cavity 5a for the lower short-circuit ring has been solidified, and the pool 4 and the inside of the upper tap 4a remain molten. ,
The next mold is quickly installed in the pool 4 to enable continuous casting. It is possible to respond quickly to mold switching without dropping the molten metal.

The gate heating means 11 and the basin heating means 12 may use both at the same time or one of them.

[0014]

According to the cage-type rotor low-pressure casting apparatus of the invention 1 or 2, the sluice heating means is provided at the upper sluice of the sluice or the sap heating means is provided at the sap. Since the part is continuously present in the vicinity between the upper gate and the mold gate, there is an effect that the lower mold can be easily separated from the pool at any time. Also has the effect that continuous casting can be performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is a longitudinal sectional view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Molten metal 2 Holding furnace 3 Stoke 4 Pool hole 4a Upper gate 5 Lower mold 5a type gate 6 Intermediate mold 7 Laminated iron core 8 Upper mold 11 Sluice heating means 12 Sluice heating means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H02K 15/02 H02K 15/02 J (72) Inventor Yoichi Oki 1-1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. In-company (72) Inventor Kouichi Manaka 1-1, Tanabe-Shinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (56) References JP-A-62-201039 (JP, A) JP-A-2- 228236 (JP, A) JP-A-53-75405 (JP, A) JP-A-4-101653 (JP, A) JP-A-7-110019 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 17/16 B22D 18/04 B22D 19/00

Claims (2)

(57) [Claims] A stove having an upper sprue is joined to an upper end of a stalk immersed near the bottom of a holding furnace capable of storing and pressurizing a molten metal, and a lower mold is provided with a mold spout capable of communicating with an upper sprue. The intermediate mold is provided with a cavity for a groove for a conductor around the shaft and surrounds the outer periphery of the laminated core, and the upper mold is provided with a cavity for a short-circuit ring. A low-pressure casting device for a cage rotor, wherein a cavity for the basin, the lower mold, the intermediate mold and the upper mold are separable from each other at the joint surface. A low-pressure casting apparatus for a cage rotor, comprising: 2. A basin having an upper sprue is joined to an upper end of a stalk immersed near the bottom of a holding furnace capable of storing and pressurizing molten metal, and a lower mold is provided with a mold spout capable of communicating with the upper sprue. The intermediate mold is provided with a cavity for a groove for a conductor around the shaft and surrounds the outer periphery of the laminated core, and the upper mold is provided with a cavity for a short-circuit ring. In a low-pressure casting device for a cage rotor, the basin, the lower mold, the intermediate mold, and the upper mold can be separated from each other at a joint surface. A low-pressure casting apparatus for a cage rotor, characterized in that: