JP2005245120A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor that can improve the flexibility of a magnet shape and that can restrain the drop of the amount of a magnetic flux. <P>SOLUTION: This electric motor comprises a stator 10 and a rotor 20 on which permanent magnets 25 are arranged in a plurality of magnet-embedding portions 24 formed in the circumferential direction of a rotor core 21. In this motor, it is configured that the permanent magnets 25 are fixed to the magnet-embedding portions 24 with a conductive resin 26. In the shape of the magnet-embedding portion formed principally by a mold, the shape of the permanent magnets is made changeable without renewing the mold so that the amount of the magnetic flux to be generated from the rotor becomes adjustable economically. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of an electric motor that realizes high efficiency and high reliability.

  2. Description of the Related Art Conventionally, an embedded magnet type electric motor generally used for an air conditioner, a compressor of a refrigerator, and the like includes a stator 10 and a rotor 20, as shown in FIG. It is concentrically held in a rotatable manner. In the rotor 20, a permanent magnet 22 is embedded in a rotor core 21. End plates (not shown) are attached to both ends of the rotor core, and are fixed by passing rivets (not shown) through caulking holes provided in the rotor core. A shaft is inserted into the shaft hole 23.

  In addition, the stator 10 directly attaches the three-phase windings 13U, 13V, and 13W to the six teeth portions 12 provided on the stator core 11 via an insulator (insulation film, insulator, etc .: not shown). It is given.

  The windings are three phases of U, V, and W phases and are star-connected to each other, and are 120 ° rectangular wave energization driven by energizing two phases of the three phases at the same time. The applied voltage is changed by PWM control.

  The rotor 20 is rotated around the shaft by a rotating force that combines the magnet torque and the reluctance torque by the rotating magnetic field generated by the current flowing through the windings 13U, 13V, and 13W applied to the stator 10.

  Since the permanent magnet of the rotor is inserted with a certain gap in the magnet embedded portion 24 installed in the rotor core, the permanent magnet and the rotor core rub against each other. In particular, at the time of magnetizing, at the time of starting, at the time of stopping, and during operation in an overload state, the coating film was scratched or peeled off due to the vibration. For this reason, some permanent magnets are usually fixed with an adhesive (for example, see Patent Document 1).

Some of them are mechanically fixed by the shape of the end plate (see, for example, Patent Document 2).
JP 2000-197291 A Japanese Patent Laid-Open No. 8-88863

  When a permanent magnet having a different shape is inserted into the magnet embedded part of the rotor core, in the embedded magnet type rotor, there is a one-to-one correspondence between the shape of the magnet embedded part of the rotor core and the shape of the permanent magnet. Since the amount of magnetic flux generated from the rotor is greatly reduced by increasing the gap between the magnet embedded portion of the rotor core and the permanent magnet, there is a problem that the degree of freedom of the permanent magnet shape is very low.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide an electric motor that can increase the degree of freedom of the magnet shape and can suppress a decrease in the amount of magnetic flux.

The electric motor of the present invention has been made in view of the above-described conventional problems, and the permanent magnet disposed in the permanent magnet embedded rotor constituting the electric motor is fixed to the magnet embedded portion with a conductive resin. is there.

  According to the electric motor of the present invention, it becomes possible to change the permanent magnet shape without renewing the die shape in the magnet embedded portion shape uniquely formed by the die, economically from the rotor. It is possible to adjust the amount of generated magnetic flux.

  Moreover, the magnetic resistance by a space | gap can be reduced and the fall of the amount of magnetic flux can be suppressed.

  The invention according to claim 1 of the present application is an electric motor including a stator and a rotor in which permanent magnets are arranged in a plurality of magnet embedded portions formed in a circumferential direction of a rotor core, wherein the permanent magnet is a magnet embedded portion. The motor is characterized in that it is fixed by a magnetic conductive resin, and the magnetic resistance can be greatly reduced compared to the case of fixing by a conventional non-magnetic resin, etc., and the amount of magnetic flux generated from the rotor is reduced. Can be suppressed.

  A specific example of the electric motor according to the present invention will be described below with reference to FIG. In FIG. 1, the same components as those in FIG. 2 showing the conventional electric motor are denoted by the same reference numerals, and the description thereof is omitted.

  The thickness of the permanent magnet 25 in this electric motor is made thinner than the conventional electric motor (hereinafter referred to as “conventional product”) shown in FIG. Specifically, when the thickness T3 of the permanent magnet 25 and the thickness T2 of the conventional permanent magnet 22 (see FIG. 2) are set, the relationship between them is set to T3 = (1/2) × T1.

  That is, the permanent magnet amount of the electric motor of the present invention is ½ that of the conventional product, and the amount of magnetic flux by the permanent magnet 25 is reduced to ½ or less, but is fixed by the conductive resin 26. Thus, it was possible to suppress the decrease in the amount of magnetic flux of the permanent magnet 25 and to obtain an increase in the amount of magnetic flux of 10% as a whole.

  The permanent magnet 25 may be fixed to the magnet embedded portion 24 formed in the rotor core 21 by molding with a magnetic conductive resin 26. As the magnetic material of the magnetic conductive resin 26, soft ferrite or As the magnetic conducting resin, the atomized iron powder is preferably PBT, PET, PPS, LCP or other thermoplastic resin.

  The electric motor according to the present invention reduces the magnetic resistance of the gap between the magnet embedded portion and the permanent magnet portion, can suppress the decrease in the amount of magnetic flux, and can economically adjust the amount of magnetic flux generated from the rotor. It is useful as an electric motor having high efficiency and high reliability.

The figure of the magnet embedded type electric motor in Embodiment 1 of this invention Figure of conventional magnet-embedded motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stator 20 Rotor 21 Rotor core 23 Shaft hole 24 Magnet embedding part 25 Permanent magnet 26 Conductive resin

Claims (1)

In an electric motor having a stator and a rotor in which permanent magnets are arranged in a plurality of magnet embedded portions formed in the circumferential direction of the rotor core, the permanent magnets are fixed to the magnet embedded portions by a conductive resin. An electric motor characterized by

Images