JPH02219444A - Manufacture of cage rotor - Google Patents

Abstract

PURPOSE:To stabilize the strength and stability by fitting a rotor bar having a saw-tooth cut and a hole at the end section into a rotor slot then fitting the projecting sections at the opposite ends of the bar to a metal mold and forming an end ring through molten forging thereafter casting the rotor bar. CONSTITUTION:A core 2 is laminated on a temporal shaft 8 and a rotor bar 1 is fitted in a slot. A saw-tooth cut 13 and a round hole 14 for facilitating welding are made at the end section of the rotor bar 1 and a rotor is set on a metal mold 7, then the mold is tightened by means of a moving table 12 and an end ring at one side 7a is casted. The end gate is formed through molten forging by pouring molten through a gate 7b and casting the end section of the rotor bar 1. By such arrangement, strength and quality can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a squirrel cage rotor for a rotating electric machine.

[Conventional technology]

Conventionally, for squirrel cage rotors, two methods have been put into practical use: an aluminum die-casting method in which the rotor bar and end ring are integrally molded, and a method in which the end ring is brazed or welded to a copper or copper alloy driven bar. . Further, methods for casting rotor bars are disclosed in Japanese Patent Application Laid-open Nos. 54-54209, 59052-1982, and 71824-1982.

Fig. 3 is a cross-sectional view showing a manufacturing method of a squirrel cage rotor disclosed in JP-A-54-54209, and Fig. 4 is a sectional view of the rotor shown in JP-A-51-71824. This is the end shape of the bar. In FIGS. 3 and 4, 1 is a rotor bar, 2 is an iron core, 3 is an end ring, 4 is aluminum solder or metal plating, 5 is a slit, and 6 is one end of the rotor bar.

Conventionally, aluminum die-casting has been widely used for the secondary conductor of squirrel-cage induction motors, but the one-type cast aluminum bar has low reliability at the joint between the bar and the end ring, making it difficult to maintain the joint strength. Considering this, it has not been widely adopted for reasons such as the fact that the conditions are not more advantageous than the silver soldering method for copper or copper alloys. In addition, as aluminum die-cast rotors have become larger, the flow of hot water has deteriorated, creating cavities inside the end ring on the opposite side of the casting, and deteriorating the characteristics of rotating electrical machines. In some cases, there is a risk that the end ring may break while driving.

In addition, in the aluminum die-cast casting system for the rotor bar, there are methods such as applying aluminum solder or metal plating 4 to the rotor bar 1, and making a slit 5 in one end 6 of the rotor bar to facilitate welding. .

[Problem to be solved by the invention]

With the conventional aluminum die-cast rotor manufacturing method, when the rotor becomes large, large cavities occur in the end ring, and even with the rotor bar casting method, soldering and plating work are required. Furthermore, in die-cast castings, the occurrence of shrinkage cavities in the end ring due to solidification and shrinkage is unavoidable, which poses problems in terms of quality and strength.

This invention was made to solve the above-mentioned problems, and provides a cast-in system for the rotor bar and end ring, in which the rotor bar and end ring are well welded and there is no cavity in the end ring. The purpose of the present invention is to obtain a method for manufacturing a squirrel cage rotor with good quality.

[Means to solve the problem]

The method for manufacturing a squirrel cage rotor according to the present invention includes providing a saw blade-like cut and a hole in the end of a rotor bar driven into a rotor slot, and casting this part with an end ring. This type is formed by a molten metal forging method.

[Effect]

The squirrel cage rotor in this invention is formed by having saw blade-like notches and holes at the end of a rotor bar, and casting it with an end ring using a molten metal forging method, which improves strength and quality. The top will also be stable.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing a method of casting with a rotor bar and an end ring, and FIG. 2 is a front view a and a side view showing the shape of the end of the rotor bar.

In FIG. 1, 1 is a rotor bar, 2 is an iron core, 7 is a mold for an end ring forming part, 7a is the end ring forming part, and 7b is a gate part. 8 is a temporary shaft, 9 is a conductive material, IO is a pressure plunger, 11 is a sleeve, and 12 is a movable table for mold clamping. Also, in Figure 2, 1
3 is a saw blade-like cut, and 14 is a round hole.

Next, the manufacturing method will be explained. The iron core 2 is stacked on the temporary shaft 8, and the rotor bar 1 is driven into the slot.

A saw blade-like notch 13 and a round hole 14 are machined at the end of the rotor bar 1 to facilitate welding. Then, this rotor is set in the mold 7, and after the mold is clamped by the movable mold clamping table 12, the end ring on one side 7a is cast.
An end ring is formed by casting one end of the rotor bar through a gate 7b which is larger than that in the aluminum die casting method. This type of end ring uses a molten metal forging method to push up the conductor material 9 with one runger 10, and the flow rate is 1
/S or less, and after casting until the completion of solidification,
Maintain high pressure (500 kg/ci or more). As a result, compared to conventional die-casting, there is no formation of cavities due to solidification shrinkage, welding is facilitated by the saw blade-like cuts and round holes, and the strength is also improved.

With aluminum die casting, there is no need to worry about cavities in the end ring on the non-casting side, which is a problem when increasing the size, and by forming end rings on one side at a time, it is possible to manufacture a large aluminum rotor.

〔Effect of the invention〕

As described above, according to the present invention, the rotor bar is provided with a saw blade-like notch and a round hole, and the rotor bar is surrounded by an end ring formed by molten metal forging. A large squirrel cage rotor that is sound and has no cavities in the end rings can be obtained, and those that were previously made of copper or copper alloy are now made of aluminum, which is cheaper and has better quality. This has the effect of providing a stable squirrel cage rotor.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a method of manufacturing a squirrel cage rotor according to an embodiment of the present invention, and FIG. 2 is a front view a and a side view thereof showing the shape of the end of a rotor bar according to the present invention. be. FIG. 3 is a sectional view showing a conventional method of manufacturing a squirrel cage rotor, and FIG. 4 is a front view a and a side view showing a conventional rotor bar. In the figure, 1 is a rotor bar, 2 is an iron core, 7 is a mold, 7a is an end ring forming part, 7b is a gate part, 8 is a temporary shaft, 9 is a conductive material, 10 is a pressure plunger, 11 is a sleeve ,1
2 is a mold clamping moving table, 13 is a saw blade-like cut, and 14 is a round hole. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] After driving a rotor bar with a serrated cut and a hole in the end into the rotor slot, and inserting the protrusions at both ends of the rotor bar into the mold that forms the end ring of the squirrel cage rotor. A method for manufacturing a squirrel cage rotor, characterized in that an end ring is formed by a molten metal forging method, and a rotor bar is cast around the end ring.