JPH01114340A - Solid rotor of induction motor - Google Patents

Abstract

PURPOSE:To reduce current loss by making the pressure welding and forming of the powder of conductive material to parts corresponding to a bar and an end ring by means of a hydrostatic pressure compression method. CONSTITUTION:A member 1 corresponding to an end ring makes the pressure welding and forming of the powder of conductive material to the axial ends of a solid core 3 by means of a hot hydrostatic pressure compression method. A bar 2, which is a member equivalent to a winding, makes the pressure welding and filling of the powder of conductive material into a groove 4 placed at a specific interval in the circumferential direction of the solid core 3 by means of a hot hydrostatic pressure compression method as well as the end ring 1. According to the constitution, the reactive flux increases and the lowering of efficiency can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a solid rotor for an induction motor, and more specifically to a solid rotor, also called a squirrel cage rotor, in the rotor of an induction motor. A solid rotor that belongs to Inter-Isostatic Pressing (IIIP) or Cold Isostatic Pressing (IIIP)
This relates to the structure of a solid rotor integrally molded by CIP. (Conventional technology) Small induction motors with relatively low output mainly use squirrel cage rotors. Iron core of squirrel cage rotors
An induced electromotive force is generated by the magnetic flux of the rotating magnetic field generated from the stator core, and an induced current flows through the bar, which is a conductor.The interaction between this induced current and the rotating magnetic field creates an electromagnetic force or torque that acts on the conductor. act on the rotor to rotate the rotor in the same direction as the rotating magnetic field. A rotating iron core serves as a path for rotating magnetic flux, and in order to reduce iron loss, conventionally, a silicon steel plate or an electric iron plate is punched out using a press, and a shaft hole is inserted in the center and a bar that becomes a conductor is inserted in the outer periphery. A plurality of slots provided along the outer periphery of the iron core are formed, and a large number of press-formed core forming plates are stacked in the axial direction to form a core. To assemble the squirrel-cage rotor, use a jig or the like to firmly drive a hard copper bar into the slot, and insert the outer end of the bar protruding from the axial outer end of the laminated core into a copper end ring. A method of connecting and shorting was used. As an alternative method, a conductive metal such as aluminum is injected through a slot in the iron core using a die-casting method.
Another method is to cast the end ring and bar together and assemble them at the same time. In the case of a laminated type rotor core, the conductive material bars may damage the insulating layer of the steel plates, while in the case of die casting, hot isostatic pressing, etc., conductive material may be created in the gaps between the laminated steel plates. There was a problem in that the ineffective magnetic flux increased due to the inflow of material, resulting in a decrease in efficiency. In addition, when the casting method is used, there are problems in that air tends to enter the inside of the conductor during casting and cooling, and that the laminated steel plates are welded to each other. Instead of such a laminated type rotor core, the rotor core shown in Fig. 3 (
As shown in A) and (B), thick plates of pure iron or soft iron are rolled into a cylindrical shape, or in the case of a small motor, the motor is shown in Figure 4 (A).
As shown in (B), a round steel bar is cut and molded into one piece to form a solid rotor. In such a solid rotor, the iron core also serves as a secondary conductor, so in order to maintain the directionality of the current, narrow grooves are provided in the axial direction, and short-circuit rings, or end rings, on both sides in the axial direction are welded or brazed. Installing. In the example shown in FIGS. 3(A) and 3(B), the cylindrical core 11 is welded together so as to be supported by the shaft 13 via four spiders 12, and one cylindrical core 11 is connected to the magnetic circuit and The spider 12 acts as a secondary conductor and also serves as a radio circuit.
supports the iron core 11 and transmits power to the shaft 13, and the space between the spiders serves as a cooling passage, so that the shaft 13 transmits the power to the outside. Furthermore, in the example shown in FIGS. 4(A) and CB), the rotor 14 is
Portions corresponding to the cylindrical core 11, spider 12, and shaft 13 in the figure are machined integrally from round steel, with thin grooves 15 on the outer periphery, and short-circuit rings on both end surfaces made of steel plates with good conductivity. That is, the end ring 16 is attached by welding. The rotor described above is combined with a separately manufactured stator to convert electrical energy into mechanical energy as an induction motor. However, since end rings are attached by welding, it takes a lot of man-hours to weld, braze, etc. to ensure a secure attachment, and the area of the attachment surface with the steel part may vary, and the strength of the joint surface is low. The problem was recognized. [Means for solving the problems] As a means for solving the above problems in the conventional technology,
In the present invention, the rotor core is a solid type, and the core is made by winding a steel plate into a cylindrical shape or by cutting and forming a cylindrical shape from soft electromagnetic wire, etc., and has a monument and a shaft hole for filling the portion corresponding to the bar with a conductive material. Form and prepare. Powder of a conductive material such as aluminum or copper is integrally molded into the groove of the thus prepared iron core and on both axial end faces by hot isostatic pressing (HIP) or cold isostatic pressing (CIP). The rotor is a solid rotor. Even when using the hydrostatic pressure wJ (pressurization) method, the powder of the conductive material may protrude circumferentially beyond the groove, or there may be irregular contact between the end plate and adjacent bars. Surface contact may occur. The structure of an induction motor is that among the current flowing through the rotor, only the current flowing in the axial direction of the rotor contributes to the rotational torque, and the current flowing in the circumferential direction increases reactive magnetic flux and causes a decrease in efficiency. Become. To solve this problem, there is no aj! on the inner circumferential surface of the groove and both axial end surfaces of the core. This problem was solved by applying a ceramic paint, etc., and curing it by heating, and then applying a hydrostatic compression method to press-mold the powder of the conductive material. Hot isostatic compression method is 10110~2000Kg/Cm
It is a technology in which the object to be processed is compressed at a high temperature of 2000"C under the gas pressure of green gas, and is widely used especially in the field of powder metallurgy.The cold isostatic pressing method is the same as the hot isostatic pressing method at other than the processing temperature. [Example] Example l !51 Figures (A) and (8) show the first embodiment of the present invention, and Figure 1 (B) is similar to Figure 1 (A). This is a side sectional view taken along the line B-B, and FIG. 1(A) is the A--
There is a front sectional view taken along line A. Reference numeral 1 in the drawing indicates a member corresponding to an end ring, and indicates a state in which conductive material powder is crimped onto both axial end faces of the solid core 3 by hot isostatic compression, and reference numeral 2 indicates a member corresponding to the winding. It is a bar which is a corresponding member, and like the end ring 1, conductive material powder is pressed into the groove 4 arranged at a predetermined interval in the circumferential direction of the solid core 3 by hot isostatic compression method. It shows the filled state. Embodiment 2 FIGS. 2(A) and 2(B) show a second embodiment of the present invention, which differs from the first embodiment in that the inner peripheral surface of the groove 4 and the solid core 3 are different from the first embodiment. The insulating layer 5 is formed on both end faces in the axial direction by applying an inorganic ceramic paint or the like and then hardening it by heating. This insulating layer 5 prevents the conductive material from protruding in the circumferential direction and connecting adjacent bars when hot isostatic compression is applied, thereby increasing reactive magnetic flux and reducing efficiency. It will be implemented when there is a great need. Effects of the Invention The solid rotor according to the present invention is constructed as described above and achieves the following effects. 1) Powder of a conductive material is statically applied to the portions corresponding to the bars and end rings. Pressure molding is carried out using the hydraulic compression method, so current loss is low and efficiency is high. 2) Rotor current loss is low, so rotor temperature rise can be reduced. 3) The material and groove shape of the conductive material powder are carefully selected. Characteristics can be easily selected by making appropriate selections. 4) Increase in reactive magnetic flux can be reduced by an insulating layer made of ceramic material or the like without paint.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are a front sectional view and a side view showing the first embodiment of the present invention, respectively; Figures 2 (A) and CB)
3(A) and CB) are respectively a front sectional view and a side sectional view showing the second embodiment of the present invention, and FIG. A)
and (B) are a side view and a front cross-sectional view, respectively, of a solid rotor machined from a conventional steel round bar. Reference numeral 1 in the drawings: a portion corresponding to an end ring that is crimped and molded by hot isostatic compression; 2: a portion that corresponds to a bar that is crimped and molded by hot isostatic compression; 3: Solid = 7.4: Groove. 5: Insulating layer 5° where the inorganic paint is heated and cured after being applied.Representative: Patent Attorney Takeo Goto, Patent Attorney Haruya Saito, Patent Attorney Patent Attorney Iso Fujiki Figure 1 (A) (B) Figure 2 1 End ring equivalent part 2 - Bar equivalent part 3 Solid core 4 groove 5 Insulating layer 3 (A) (B) Figure 4 (A) ' (B)

Claims (1)

[Claims] 1. A solid made of iron-based material to a predetermined size and having a plurality of grooves extending in the longitudinal axis direction at predetermined intervals in the circumferential direction, and both axial end faces. a core, a bar portion formed by filling the groove of the solid core with conductive material powder by hot isostatic pressing (HIP) or cold isostatic pressing (CIP); and this bar. What is claimed is: 1. A solid rotor for an induction motor, comprising: a solid core; and a member corresponding to an end plate integrally and continuously crimped to both axial end surfaces of a solid core. 2. A solid core machined to a predetermined size from a ferrous material and having a plurality of grooves extending in the longitudinal axis direction at predetermined intervals in the circumferential direction, and both axial end faces; A coating layer of an inorganic paint is applied to the inner circumferential surface and both axial end surfaces of the plurality of grooves in the core body and then cured by heating, and a conductive material is coated through the coating layer of the inorganic paint. The powder is processed by hot isostatic pressing (HIP) or cold isostatic pressing (C
IP), a bar portion formed by filling the groove portion of the solid core, and a member corresponding to an end plate that is integrally and continuously crimped to the bar portion and both axial end surfaces of the solid core. A solid rotor for an induction motor, characterized in that it has a solid rotor.