JPH02228237A - Manufacture of squirrel cage rotor - Google Patents

Abstract

PURPOSE:To obtain a rotor, rigid in structure, short in manufacturing time and suitable to super high speed as well as large capacity in the outer peripheral speed thereof, by a method wherein a rotor bar, an end ring and a push ring are connected to a core under high temperature and high-pressure atmosphere so that respective materials are connected integrally with each other in solid phase. CONSTITUTION:When a can 8 is pressurized in inert gas under high-temperature high pressure atmosphere by an isotropic pressure from the outside thereof, a gap 6a between a rotor bar 2 and a slot 3 as well as a gap between an end ring 4 and a core 1 and the gap 6 of a ring 5 are eliminated since the rotor bar 2 and the end ring 4 are expanded to the side of the outer periphery thereof by a volume coinciding with the gaps 6, 6a whereby all of boundaries between respective members are connected in solid phase together with the can 8. Thereafter, the can 8 is removed and the axial thickness of the outer diametral side of the push ring is machined and formed so as to be thinner than the axial thickness of the inner diametral side of the same so that a stress is applied on the ring 5 evenly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method for manufacturing a squirrel cage rotor for a one-rotation electric machine.

(Prior Art) In general, rotary electric machines based on various principles have been manufactured and used, and the most common and frequently used one is an induction motor. The squirrel-cage rotor of this induction motor has a cylindrical laminated core with multiple axial slots on its outer periphery, and an aluminum rotor bar that passes through the slots and end rings installed at both ends of the laminated core. Most rotors are die-cast using a cast machine. Rotors manufactured in this way require a die-cast mold, so there is no cost benefit unless they are mass-produced. It is uneconomical because there is nothing to do and the mold becomes large.

Therefore, for large-capacity products, the rotor bar and end ring are made of steel, a copper bar is hammered into the slot, and the end ring is formed by brazing the copper bar with silver.

(Problem to be Solved by the Invention) The rotor of the induction motor manufactured as described above cannot withstand ultra-high speed rotation. That is, the rotor manufactured by die-casting has a limit of around 180 mh at the circumferential speed of the rotor, and the end ring breaks. In a copper bar type rotor, the outer circumferential speed of one rotor does not reach 180 m/s due to the instability of dimensions when silver brazing the copper bar and end ring, and the instability of the quality of the silver brazing itself. It is said that.

The present invention is robust, has a short manufacturing time, and has a rotating viscount peripheral speed of 2
An object of the present invention is to provide a method for manufacturing a squirrel cage rotor for a rotating electric machine suitable for ultra-high speed and large capacity exceeding 00 m/s.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the first means of the present invention includes a cylindrical iron core having a plurality of axial slots on the outer periphery, and a cylindrical iron core having a plurality of axial slots on the outer circumference, and A copper rotor bar, a copper end ring that is engaged with both ends of the rotor bar, and a part of the end ring that presses the end ring from the outside in the axial direction and touches the end surface of the end ring through a wedge-shaped gap that tapers toward the outside diameter. The outer periphery of the rotor bar and the end ring is provided with a presser ring made of non-magnetic steel in contact with each other, and forms an assembly in which the outer periphery of the rotor bar and the end ring extends out to the outer periphery of the iron core by a volume corresponding to filling the surrounding gap.
A can is installed to vacuum enclose this assembly, and it is heated and pressurized in a high-temperature, high-pressure atmosphere.

It is characterized in that the assembly is welded in phase, and then the can is removed, and the axial thickness on the outer diameter side of the presser ring is made thinner than the axial thickness on the inner diameter side.

As a second method, the cylindrical iron core is made by laminating thin iron plates such as silicon steel plates, and before the can is attached, solid state bonding is performed by applying high temperature and high pressure in advance, or high temperature and medium pressure The present invention is characterized in that the gap in the axial direction of the punched plate is eliminated by applying the same pressure as the first means.

In addition, the third means is characterized in that an inner peripheral ring made of copper is interposed between the inner peripheral surface of the end ring holder and the iron core shaft, and in addition, as in the first means or the second means. shall be.

(Function) According to the manufacturing method configured in this way, the first, second,
In the third method, the rotor bar, end ring, and presser ring can be integrally solid-phase bonded to each other in a high-temperature, high-pressure atmosphere to the iron core, resulting in an extremely robust rotor.

Embodiments Embodiment 1 A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a cross-sectional view of the main parts of a rotor manufactured by the method of the first embodiment of the present invention, and FIGS. 2 and 3 show the state of the manufacturing process. 3 is a cross-sectional view taken along the line nu in FIG. 3, and FIG. 3 is a vertical cross-sectional view taken along the line ■-■ in FIG. (1) is an iron core in which thin iron plates such as silicon steel plates are laminated in a cylindrical shape and joined by applying high temperature and high pressure, or by applying high temperature and medium pressure to fit the thin iron plates so that there are no gaps between them; (1a) is the shaft, (2) is a rotor bar with a rectangular cross section and made of oxygen-free copper, (3) is a slot, (4) is an end ring with a rectangular cross section and is made of oxygen-free copper, and (5) is a non-slip that supports the end ring. Magnetic material 1 is a presser ring made of stainless steel, for example, and a wedge-shaped gap (6) tapering toward the outer diameter is provided on the inner side surface. (7) is a presser ring (5) and a shaft portion (la). This is an inner circumferential ring made of oxygen-free copper that joins.

As shown in FIGS. 2 and 3.

The slot shape is wedge-shaped, and the rotor bar (2)
has a rectangular cross section, so there is also a wedge-shaped gap (6a) that tapers toward the outer diameter.
2), the end ring (4), the presser ring (5), and the inner circumferential ring (7) will be referred to as an assembly.

In this assembly, the outer circumferences of the rotor A-(2) and the end ring (4) are extended to the outer circumferential side of the iron core (1) by a volume sufficient to fill the surrounding gaps (6) and (6a). 8) is a vacuum-sealed mild steel can that encases these assemblies. (9) is an annular gap around the outer periphery of the presser ring that is created when the above-mentioned member is disposed.

The items shown in Figures 2 and 3 are heated from the outside of the can (8) in an inert gas at a high temperature (for example, 800 to 950°C).
When isostatic pressurization is applied for a predetermined time (1 to 2 hours) in a high pressure (for example, 500 to 100,100 O/d) atmosphere, the rotor bar (2) and end ring (4) form a gap (6).

Since the volume corresponding to (6a) is extended to the outer periphery,
Gap (6a) between rotor bar (2) and slot (3),
The gap between the end ring (4) and the iron core (1) (the slight force 1 is not shown) and the gap (6) between the retainer ring (5) are reduced, and the boundaries of each member are the combination of steel materials. Since it is only a can (8), it is solid phase bonded together with the can (8). After that, remove the can (8) by machining,
The retainer ring (5) is processed and shaped so that the outer axial thickness of the retainer ring (5) is thinner than the inner axial thickness so that stress due to centrifugal force is evenly applied to the retainer ring (5).

In this way, almost no steel material enters the annular gap (9), the steel material fills the wedge-shaped gaps (6) and (6a), and each member is firmly attached by solid phase welding.
A method for manufacturing a squirrel-cage rotor that is robust against rotational motion and maintains the designed shape, resulting in improved mechanical balance and electrical properties, and is suitable for ultra-high-speed, large-capacity applications with circumferential speeds exceeding 200a+/s. Become.

Example 2 In the second example shown in Figs. 4 and 5, the iron core (1) is made into a block, and a wedge-shaped gap (6) is also provided on the end ring (4) side of the iron core (1). The rest is the same as in the first embodiment.

In this way, the holding of the end ring (4) is strengthened, and the same effects as in the first embodiment can be obtained.

Example 3 In the third example shown in FIGS. 6 and 7, the inner ring (7) of Example 2 is not used, and the retaining ring (5) and the core shaft (1a) are placed in a solid state. The others are those of Example 2.
It is as follows.

In this case, since there is a solid-phase joint between irons, it is necessary to increase the degree of high temperature, but otherwise the same effects as in Example 2 can be obtained.

Other Examples/Other Examples: Inner ring (7) of Example 1
may be removed. In addition, the axial thickness of the presser ring is processed in advance so that the centrifugal force is uniform, and the can (
8), fill the gap between the can and the can with an appropriate material, and remove it after solid phase bonding.

Furthermore, the slot (3) of the iron core (1) is not limited to the wedge shape shown in the drawings, but may have a square or rectangular cross section without departing from the gist of the present invention6. Although the circumferential ring (7) is made of oxygen-free copper, the type of steel may be changed depending on the required strength (for example, chromium copper or beryllium copper) without departing from the spirit of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, each member is machined and covered with a vacuum-sealed can.

By applying high temperature and high pressure, each member is solid phase bonded, making it a robust ultra-high-speed, large-capacity machine with a circumferential speed exceeding 200 m/s, short manufacturing time, good balance, and squirrel cage rotation with good electrical characteristics. Can produce children.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the main parts of a squirrel cage rotor manufactured by the first embodiment of the method of the present invention, and FIGS. 2 and 3 show the state of the product in FIG. 1 during the manufacturing process. Fig. 2 is a vertical cross-sectional view taken along the line ■-■ in Fig. 3, Fig. 3 is a cross-sectional view taken along the line m-tn in Fig. 2, and Fig. 4 is a cross-sectional view taken along the line m-tn in Fig. 2.
FIG. 5 is a vertical cross-sectional view of the main part of the finished product of the example shown in FIG. 4, and FIG.
Fig. 7 is a vertical cross-sectional view of the main part of the completed product of the example shown in Fig. 6.
! FIG. 3 is a vertical cross-sectional view of main parts showing the state during the construction process. l... Iron core 2... Rotor bar 3... Slot 4... End ring 5... Holding ring 6゜6a... Gap 7... Inner ring 8... Can

Claims (3)

[Claims] (1) A cylindrical iron core with a plurality of axial slots on its outer periphery, a copper rotor bar inserted into the slots, a copper end ring engaged with both ends of the rotor bar, and an end ring with an axial direction. It is held down from the outside and is equipped with a non-magnetic steel holding ring that partially contacts the end face of the end ring through a wedge-shaped gap that tapers toward the outside diameter, and the outer periphery of the rotor bar and end ring fills the surrounding gap. An assembly is formed that extends out to the outer periphery of the iron core by a volume corresponding to that of A method for manufacturing a squirrel-cage rotor, characterized in that the can is then removed and the axial thickness on the outer diameter side of the presser ring is made thinner than the axial thickness on the inner diameter side. (2) The cylindrical core is made by laminating thin iron plates such as silicon steel plates, and before installing the can, solid-phase welding is performed by applying high temperature and high pressure in advance, or punching is performed by applying high temperature and medium pressure. 2. The method of manufacturing a squirrel cage rotor according to claim 1, wherein the axial clearance is eliminated. (3) Claim 1 characterized in that an inner circumferential ring made of copper is interposed between the inner circumferential surface of the end ring holder and the core shaft portion.
Or a method for manufacturing a squirrel cage rotor according to claim 2.