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RU-2861410-C1 - METHOD FOR MANUFACTURING SQUIRREL-CAGE ROTOR OF INDUCTION MOTOR

RU2861410C1RU 2861410 C1RU2861410 C1RU 2861410C1RU-2861410-C1

Abstract

FIELD: electrical engineering. SUBSTANCE: invention relates to the manufacture of induction motors with squirrel-cage rotors. The method for manufacturing a squirrel-cage rotor of an induction motor involves manufacturing laminations of the rotor magnetic core from sheet electrical steel alloy with slots for accommodating the squirrel-cage winding. The laminations are assembled into a cylindrical magnetic core of length L and the laminations are fastened together. An injection mould is made to form a casting - the magnetic core with the squirrel-cage winding. The mould contains a cavity consisting of three cylindrical parts - a central part and two end parts, and a cylindrical rod located inside the cavity coaxially therewith. The central part of the cavity is intended to accommodate the magnetic core of the rotor being manufactured. The two end parts of the cavity are intended to form the short-circuiting rings of the rotor winding. Electrical aluminium in a liquid state is injected under pressure into the injection mould with the magnetic core placed therein so that it completely fills the end parts of the cavity of the injection mould and the slots of the magnetic core. As a result, a casting is formed - the magnetic core with the squirrel-cage winding. EFFECT: increasing the manufacturability of rotor manufacture. 1 cl, 3 dwg

Inventors

  • Duyunov Evgenij Dmitrievich
  • Lomakin Sergej Evgenevich
  • Savelev Aleksandr Evgenevich
  • SEMENOV ALEKSANDR YUREVICH
  • Teplova Yana Olegovna

Dates

Publication Date
20260505
Application Date
20241114

Claims (10)

  1. A method for manufacturing a squirrel-cage rotor of an asynchronous motor, in which:
  2. - rotor magnetic circuit plates of diameter D with a central hole of diameter d 1 such that d 1 > d 2 , where d 2 is the shaft diameter of the asynchronous motor, and slots for accommodating the short-circuited rotor winding are made from sheet electrical alloy;
  3. - a cylindrical magnetic circuit of length L with a through cylindrical hole is assembled from the plates and the plates are fastened together;
  4. - a casting mold is manufactured that contains: a cavity consisting of three parts - a central part of length L, a part with a cross-sectional diameter D, intended for placing a magnetic circuit in it, and two end parts of diameter d 3 and lengths l 1 and l 2 , respectively, intended for forming short-circuiting disks of the winding; a cylindrical rod with a cross-sectional diameter d 2 , located inside the cavity coaxially with it, wherein the total length of the cavity of the casting mold is L + l 1 + l 2 , and d 2 < d 1 < d 3 <D;
  5. - the rotor magnetic circuit is placed in the central part of the mold cavity;
  6. - a casting is formed, including a magnetic circuit and a short-circuited rotor winding, by pouring electrical aluminum under pressure into a casting mold with a magnetic circuit placed in it in such a way that the aluminum fills the end parts of the cavity of the casting mold and the slots of the magnetic circuit;
  7. - cool the casting to harden the aluminum, after which it is removed from the casting mold;
  8. - form the rotor of an asynchronous motor by pressing the shaft into a through cylindrical hole in the casting;
  9. - the rotor undergoes final processing, including machining and balancing,
  10. characterized in that the formation of a short-circuited rotor winding is performed as a single technological operation, while the winding rods at both ends of the rotor are connected by short-circuiting disks.

Description

The invention relates to electrical engineering, in particular to the production of asynchronous motors (AM) with squirrel-cage rotors. A method for manufacturing a squirrel cage rotor is known, in which the rods of a squirrel cage rotor winding made of copper or brass are welded or soldered to short-circuiting rings having holes into which the rods are inserted before connection [1-3] - analogue. The disadvantage of the analog is that the production of a short-circuited squirrel-cage winding requires several technological operations, such as welding, soldering each rod separately, etc. A method for manufacturing a squirrel cage rotor is known, in which the “squirrel cage” is made by casting from aluminum or an aluminum alloy, with the rods located in the grooves of the magnetic circuit and the short-circuiting rings with ventilation blades and pins being cast simultaneously [4, Chapter 3.3 Designs of asynchronous machines] - prototype. A drawback of the prototype is that the squirrel cage rods can only be connected using short-circuiting rings. However, the use of short-circuiting discs instead of short-circuiting rings in the rotor squirrel cage is known [5]. This allows for a rotor equivalent resistance lower than that of a rotor with short-circuiting rings, which, in turn, leads to reduced rotor heating and an increase in the induction motor's power. The technical result of the proposed method for manufacturing a squirrel-cage rotor of an induction motor is as follows: - reduction of duration and simplification of the technological cycle for manufacturing a squirrel-cage rotor by reducing the number of technological operations; - simplification of the manufacture of squirrel-cage rotors for energy-efficient induction motors, which have a lower equivalent resistance compared to squirrel-cage rotors in which the winding bars are connected by short-circuiting rings. The specified technical result is achieved by manufacturing short-circuited rotors, the winding of which is performed by die-casting electrical aluminum within the framework of a single technological operation and contains short-circuiting disks instead of short-circuiting rings. The proposed method includes the following steps: 1. The rotor magnetic core (plates) are made from sheet electrical alloy. The plates, with a diameter of D, have a central hole with a diameter of d 1 such that d 1 > d 2 , where d 1 is the cross-sectional diameter of the asynchronous motor shaft, and slots for accommodating the squirrel cage rods (Fig. 1). 2. A cylindrical magnetic circuit of length L with a through cylindrical hole is assembled from the manufactured plates and the plates are fastened together. 3. A casting mold is manufactured for forming a casting - a rotor magnetic circuit with a short-circuited winding (Fig. 1). The mold contains a cavity consisting of three cylindrical parts - a central part and two end parts, and a cylindrical rod (Fig. 1, designation 1) with a cross-sectional diameter d 2 , located inside the cavity coaxially with it. The central part of the cavity of length L with a cross-sectional diameter D is intended to accommodate the magnetic circuit of the rotor being manufactured. Two end parts of the cavity of length l 1 and l 2 with a cross-sectional diameter d 3 < D are intended to form short-circuiting disks of the rotor winding. The total length of the casting mold cavity is L + l 1 + l 2 , where d 2 < d 1 < d 3 < D. 4. The magnetic circuit of the rotor being manufactured is placed in the central part of the mold cavity (Fig. 1, designation 2). 5. Liquid electrical aluminum is poured under pressure into the mold containing the magnetic core, completely filling the end faces of the mold cavity and the slots in the magnetic core. The resulting casting is a magnetic core with a short-circuited winding. 6. The casting is cooled to solidify the aluminum, after which it is removed from the mold. 7. The rotor of the AD is formed by pressing the shaft into a through cylindrical hole in the casting. 8. The rotor undergoes final processing, including machining and balancing. Implementation of the invention In accordance with the proposed method, prototype rotors were manufactured for built-in asynchronous drives in power tools and household appliances. As an example of the method's implementation, Fig. 2 shows a general view of a squirrel-cage rotor. The corresponding rotor magnetic circuit is shown in Fig. 3. The proposed method can be used for the production of general-purpose and special-purpose IM, including energy-efficient IM. Sources of information 1. Kopylov I.P. Electrical machines: Textbook for universities. - 2nd ed., revised. - M.: Higher. school; Logos; 2000 - 607 p. 2. Voropaev E.G. Electrical engineering. Ch. 5. Asynchronous machines. [Electronic resource]. URL: https://tsput.ru/res/fizika/1/VOROPAEV_2/vorop5.htm (access date: 10/30/2024). 3. Asynchronous electric motor. Design and operating principle. [Electronic resource]. U