JPS59153562A - Production of die cast rotor - Google Patents

Abstract

PURPOSE:To prevent formation of blowholes and seizure of dies and to eliminate the need for a post treatment of a gate by specifying the system of a pin gate which communicates with annular recessed space for forming an end ring of a top die of the top and bottom dies having the above-discribed space. CONSTITUTION:A rotor core 11 is attached in such a way that the end part of the slots 12 thereof faces annular recessed spaces 14, 17 for forming end rings of a bottom die 13 and a top die 16, and the dies 13, 16 are combined separably. A runner 18 for supplying a molten metal is disposed inner than the space 17 and both are connected by a pin gate 19 disposed diagonally from the bottom end of the runner 18 toward the inside circumferential surface of the space 17. Then the melt of a conductive material, for example, Al, enters the space 17 through the gate 19 from the runner 18 and flows into the slots 12. Since the molten metal flows zigzag in the slots 12, the generation of die seizure and blowwhole is made difficult. The cutting trace 20 of the Al solidified in the feed part of the gate 19 is on the inside of an end ring 21 and affects less the mechanical balance of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a die-cast rotor for an induction motor, in which a secondary conductor is formed by injecting molten conductive material into slots provided in a rotor core.

[Technical background of the invention]

Generally, in the rotor of a small induction motor, a molten conductive material such as aluminum is injected into slots provided in the rotor core, and an end ring that commonly connects the secondary conductor and both ends thereof is integrated. So-called die-cast rotors are widely used.

Such a die-cast rotor has conventionally been manufactured as shown in Fig. 1. That is, in Figure 1, the ring is a rotor core made of a large number of laminated steel plates, and the slot r for the secondary conductor is located near the outer surface of the rotor core, as shown in Figure 2.
A plurality of iz are provided at regular intervals. A3 is a lower mold, which has an annular recessed space for molding the end ring, and the rotor core αυ is attached so that this recessed space (141) and one end of each slot (1z) face each other. (1
Reference numeral 61 denotes an upper mold, which also has an annular recessed space a for end ring molding, and is separably assembled with the lower mold (13) so that it faces the other end of each slot a2 of the rotor core circle. A runner (181) for supplying a molten conductive material (hereinafter referred to as molten metal) is formed in the upper mold OD, and the tip thereof has an extremely small diameter (for example, 2 in diameter). It communicates with the upper surface of the four-part space αη through a gate (11), namely, a bin gate (11).

In the above configuration, the bath water passes through the pin gate 4 from the runner α piece, and is injected into the recessed space (17) of the upper mold opening, into each slot 0, and into the recessed space I of the lower mold mouth.Then, after cooling and solidifying. , the upper mold (1υ) and the lower mold (α) are separated, and the solidified conductive material is cut at the bin gate (19) to form a die-cast rotor as shown in Figure 2.

Since the above manufacturing method uses a bingate ring, as shown in Figure 2, the trace of the pouring part after molding (2) is small (small, and its position is on the end ring 011, so even if it is left as it is, the rotor It has little effect on the mechanical balance.

[Problems with background technology]

However, using a bin gate requires greater injection pressure than using a regular gate to pour the same amount of hot water in the same amount of time. That is, since the injection pressure is proportional to the square of the flow area of the gate, a large injection pressure must be applied. For this reason, when the molten metal flows into the slot, air is drawn in, making it easy for cavities to occur.

As is well known, when a cavity occurs, the motor characteristics deteriorate and the variation increases.Furthermore, when operated as a motor, it becomes a source of vibration and noise.

Further, since the injection direction of the bin gate a and the length direction of the slot 112 are the same, the molten metal may be injected in a state where the illustrated upper end opening of the slot 02 and the bin gate H overlap. In this case, the high temperature and high pressure molten metal is in the slot a2J.
Since it passes through and directly hits the inner wall surface of the lower mold 03), seizure occurs in the mold, significantly shortening its life. Also,
In the parts of the product where this baked-on embossment occurs, the material peels off and the surface becomes rough, causing problems in terms of product quality.

[Purpose of the invention]

The purpose of the present invention is to prevent the formation of cavities and mold seizure, which are disadvantages of the bin gate method, and to take advantage of the advantage of the bin gate method, which is that post-processing of gates is not required and is highly suitable for mass production. Our goal is to provide the following.

[-Summary of the invention]

In the method for manufacturing a die-cast rotor according to the present invention, a rotor core having a plurality of slots is attached to a mold having an annular concave space for forming an end ring opposite to the end of each of the slots, and a die-cast rotor is placed in the concave space. A molten conductive material is injected from the inside through a diagonally communicating pin gate, and the conductive material is poured into the slot through the recess space, and by injecting from the diagonally communicating pin gate, The conductive material is meandered and uniformly poured into the slot to prevent the formation of cavities and seizure.

[Embodiments of the invention]

Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. Note that portions corresponding to FIG. 1 and FIG. 2 will be described with reference numerals 4-'.

In Figure 3, the structure of the lower mold αa is the same as that of the conventional one shown in Figure 1, and the concave space α for end ring molding is
4) and a plurality of slots 0z is installed so that the open end of the slot (14) faces the recess space I.The upper mold (16) is the same (an annular recess for end ring molding). The runner QB for supplying the molten metal is placed inside the annular recessed space (171), and the space between the runner bracket and the annular recessed space αη is from the lower end of the runner shaft to the recessed space. The pin gates (11) are connected by a pin gate (α) arranged diagonally toward the inner peripheral wall surface of the pin gates (11).The number of pin gates (11) changes depending on the size of the rotor to be molded, and is one or more. .

In the above configuration, the molten metal enters the recess space αη from the runner α barrel through the pin gate (19) and flows into the slot ■.Here, the pin gate circle is connected to the recess space (171
Since the molten metal is provided obliquely toward the inner circumferential wall surface of the slot, the molten metal does not flow straight into the slot (1
Flows into 2. For this reason, the molten metal flows uniformly, and the flow rate is also slow, making it difficult for mold seizure and formation of cavities to occur.

After the injection, the molten metal is cooled and solidified. Thereafter, the upper die and the lower die QJ are separated, the solidified conductive material is cut at the injection part of the pin gate α9, and the die-cast rotor shown in FIG. 4 is taken out. In this case, a pin gate (1'l trace) is formed inside one end ring (2υ) of the rotor, but its shape is extremely small, and since it is inside the end ring Qυ, it is difficult to maintain the mechanical balance of the rotor. There is almost no impact on the process, and post-processing such as machining is not required.

〔Effect of the invention〕

As described above, according to the present invention, when injecting molten metal into the slot formed in the rotor core, the pin gate is connected obliquely from the inside of the annular concave space for forming the end ring toward the concave space. As a result, the molten metal flows into the slot in a meandering manner, so the molten metal flows uniformly and at a low flow rate, preventing the formation of cavities and seizures (improving rotor balance and increasing motor efficiency). etc., the electrical and mechanical characteristics of the motor are improved,
It is also possible to extend the life of the mold. Furthermore, by using a pin gate, post-processing of the gate is not required, and it is possible to manufacture a product at a low cost with excellent mass productivity.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are a sectional view showing the state of manufacture by the conventional method, a plan view of the rotor molded by the method, and Fig. 3.
The figure is a cross-sectional view showing the manufacturing state in one embodiment of the method for manufacturing a die-cast rotor according to the present invention, and Figure 4 is a perspective view showing the die-cast manufactured by Figure 3. H--o-takoah, (121--sot, (Iue
-・Type, (141Gη conflict・Annular concave space, (2)・・
pin gate. February 22, 1980 Inventor Tomi Nakamura Patent applicant Toshiba Thermal Appliances Co., Ltd. f

Claims (1)

[Claims] (1) A rotor core having a plurality of slots is attached to a mold having an annular concave space for forming an end ring facing the ends of each of the slots, and a bin gate is connected diagonally from inside the concave space. A method for manufacturing a die casting rotor, characterized in that a molten four-way material is injected through the slot, and a conductive material is poured into the slot through the recess space.