JP2018191459A - Electric motor and washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of noise that is oscillation which occurs from an electric motor when pulsation torque, one of noise caused by the electric motor among various factors of a noise occurrence, is large and which is transmitted to a surrounding housing portion, in recent years when a washing machine is used in a home in many cases and needs for low noise has been enhanced every year since many people wash at night.SOLUTION: An electric motor is composed of a stator and a rotator provided so as to rotate with respect to the stator. The rotator has a rotation magnetic pole that is a rotor core of a magnetic steel sheet laminated, and a permanent magnet disposed on both sides of the rotation magnetic pole. A plurality of these are disposed in a circular ring shape and completely covered with resin material to be fixed, and a shaft connection member is provided through a reinforcement member on the inner diameter side of the rotation magnetic pole and the permanent magnet. The rotation magnetic pole is composed by laminating a first rotor core having a projection portion projecting in a circumferential direction to an external diameter side end portion and a second rotor core not having the projection portion at the external diameter side end portion.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a magnet motor, and more particularly, to a washing machine using the magnet motor, and more particularly to a drum type washing and drying machine.

  The current drum-type washer-dryer is mainly driven by a magnet motor directly connected to the rotating shaft of the rotating drum (direct drive method). Usually, in a drum-type washing machine, it is necessary to drive the rotating drum at low speed and high torque during the washing process. It is arranged and inserted into the rotor core to efficiently use the magnetic flux generated from the permanent magnet. In this case, it is possible to use the magnetic flux generated from the permanent magnet more efficiently by eliminating the outer diameter side and inner diameter side iron portions of the rotor core and providing a gap.

  Many washing machines are used in the home, and in recent years there are many people who wash at night, and the need for low noise is increasing year by year. There are various causes of noise generation, but pulsation torque is one of the noises caused by motors. When the pulsating torque is large, vibration is generated from the electric motor, which propagates to the surrounding casing and becomes noise.

  Various methods have been proposed as methods for reducing the pulsation torque of an electric motor. For example, a method using non-concentric shapes that are convex on the inner peripheral surface of the teeth in the stator and the outer peripheral surface of the magnetic pole core in the rotor. There is also.

  Further, as in Patent Document 1, two or more regions with different magnetic circuit designs are provided in the direction of the rotation axis due to the change in the cross-sectional shape in the direction perpendicular to the rotation axis of the rotor. A technique for reducing the above has been proposed.

Japanese Patent No. 5897073

  When the pulsation torque is large, vibrations are generated from the electric motor, which propagates to the surrounding housing part and causes noise. In order to further reduce the noise, it is necessary to reduce the pulsation torque, and an object of the present invention is to provide an electric motor having a small pulsation torque and a washing machine to which the electric motor is applied.

  The electric motor according to the present invention includes a stator and a rotor provided to rotate with respect to the stator, and the rotor includes a rotating magnetic pole formed by laminating a rotor core of an electromagnetic steel plate, and the rotating magnetic pole. Permanent magnets arranged on both sides of the magnet, and a plurality of these are arranged in an annular shape and are fixed by covering the whole with a resin material. The shaft is connected to the inner diameter side of the rotating magnetic pole and the permanent magnet via a reinforcing member The rotor is provided with a member, and the front rotating magnetic pole protrudes from a first rotor core having a protruding portion protruding in a circumferential direction at an outer diameter side end portion and an outer diameter side end portion. A second rotor core that does not have a portion is laminated and configured.

  ADVANTAGE OF THE INVENTION According to this invention, the electric motor which reduced the pulsation torque at the time of driving | operation, and the washing machine which adapted this electric motor can be provided.

It is a general-view figure of the drum type washing machine concerning one embodiment of the present invention. It is a longitudinal cross-sectional view along the rotating shaft of the electric motor in connection with one Embodiment of this invention. It is a radial direction fragmentary sectional view of the electric motor in connection with one Embodiment of this invention. It is a general-view figure of the rotor core concerning one Embodiment of this invention. It is a rotor core lamination | stacking block diagram of the rotating magnetic pole in connection with one Embodiment of this invention. It is an external appearance perspective view of the outer peripheral side of the rotor in connection with one Embodiment of this invention. It is a torque waveform diagram at the time of dehydration of the electric motor concerning one embodiment of the present invention. It is a torque waveform comparison figure at the time of the spin-drying | dehydration of the electric motor in connection with one Embodiment of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. First, after describing the overall configuration of a drum type washing machine (hereinafter referred to as a washing / drying machine) according to the present embodiment, an electric motor mounted on the drum type washing machine will be described.

  FIG. 1 is an external perspective view of a washing / drying machine according to an embodiment of the present invention.

  Reference numeral 401 denotes a substantially box-shaped housing that constitutes the outline of the washing / drying machine 400. The housing 401 is mounted on a synthetic resin base 402 that supports the housing 401. In FIG. 1, in order to show the inner structure of the housing 401 of the washing / drying machine 400, an upper surface cover (not shown), a front cover (not shown), and a lower front cover (not shown) constituting the housing 401 are shown. The state of having been removed is shown. In FIG. 1, reference numeral 406 denotes a side plate constituting the housing 401, and reference numeral 407 denotes a back cover.

  In the washing / drying machine 400, laundry such as clothes is taken in and out of the drum 404 through an opening 408 provided substantially at the center of the front surface. The opening 408 can be opened and closed by a door 403 that rotates around a hinge (not shown).

  The drum 404 has a bottomed cylindrical shape that is rotatably supported, and has a plurality of through holes for water flow and ventilation on the outer peripheral wall and the bottom wall thereof. The rotation axis of the drum 404 is inclined so that the horizontal or opening 408 side becomes higher.

  The outer tank 405 is formed in a cylindrical shape and includes a drum 404 on the same axis. Incidentally, the drum 404 contained in the outer tub 405 functions as a washing room, a dehydration room, and a drying room. An opening on the front surface of the outer tub 405 is provided with an outer tub cover (not shown) made of synthetic resin, and water can be stored in the outer tub 405. A drain outlet (not shown) is provided on the bottom surface of the outer tub 405.

  The outer tub 405 is supported in an anti-vibration manner by a suspension 409 (consisting of a coil spring and a damper) whose lower side is fixed to the base 402. The upper side of the outer tub 405 is supported by an auxiliary spring (not shown) attached to the upper reinforcing member 410, and this auxiliary spring prevents the outer tub 405 from falling in the front-rear direction.

  In such a washing and drying machine 400, washing water is stored in the outer tub 405, and the drum 404 is rotationally driven by the electric motor 1 described below to wash the laundry. In the washing / drying machine 400, the electric motor 1 rotates the drum 404 when rinsing, dehydration, and drying are performed after the washing is completed.

Next, the electric motor 1 according to the present embodiment will be described in more detail.
As shown in FIG. 1, the electric motor 1 is arranged at the outer center of the rear end face of the outer tub 405. In FIG. 1, the outer shape (contour) of the electric motor 1 viewed from the direction of the rotating shaft (the extending direction of the rotating shaft) is indicated by a hatched line (broken line). The rotating shaft of the electric motor 1 passes through the outer tub 405 and is coupled to the drum 404.
FIG. 2 is a longitudinal sectional view of the electric motor along the rotation axis of the electric motor according to the embodiment of the present invention.
As shown in FIG. 2, the electric motor 1 is attached to the back bottom (outer tank base) side of the outer tank 405 (see FIG. 1) via a stator base 300 with a fastener (not shown) such as a screw. .
The stator base 300 is mainly composed of a flange portion 300 a attached to the outer tub 405 and a body portion 300 b in which the rotating shaft 320 of the electric motor 1 is built.
A water seal 311 is press-fitted inside the boss portion 310 provided on the body portion 300b on the side passing through the bottom of the outer tub 405 (see FIG. 1). The water seal 311 prevents the washing water in the outer tub 405 from leaking to the outside of the outer tub 405 via the electric motor 1.
Bearings 313a and 313b for rotating and supporting the rotating shaft 320 are housed inside the body portion 300b.
The rotating shaft 320 extends in the body 300b away from the outer tub 405 (see FIG. 1), and the tip of the rotating shaft 320 protruding from the body 300b is a rotor described in detail later. 200 is inserted. Incidentally, a screw portion is formed at the tip of the rotating shaft 320, and the rotor 200 is attached to the rotating shaft 320 by a nut 314 screwed into the screw portion.
Further, as will be described later, the stator 100 to be disposed on the outer peripheral side of the rotor 200 is fixed to the flange portion 300a with a screw 315.
The stator 100 is mounted with a thermal protector holder (not shown) on which a Hall IC holder (not shown) for detecting the magnetic pole position of the rotor 200 and a thermal protector for detecting the heat generation of the winding are mounted. . Incidentally, the Hall IC holder detects the magnetic flux on the end face of the rotor 200 and detects the polarity and position. Further, the thermal protector holder is configured to cut off the power supply for energizing the winding when the electric motor 1 is overloaded.
A flange 316 for attaching the drum 404 is fitted and fixed to the rotating shaft 320.
3 is a partial sectional view taken along line IIIa-IIIa in FIG.
As shown in FIG. 3, the rotor 200 fixed to the rotary shaft 320 (see FIG. 2) is disposed inside the stator 100.
The stator 100 has a number of fixed magnetic poles 120 around which a stator coil 110 is wound, and has a shape 121 in which the tips of all the stacked stator cores protrude in the circumferential direction.
In the rotor 200, a large number of permanent magnets 220 are arranged on a rotating magnetic pole 210 formed by laminating a first rotor core and a second rotor core made of an electromagnetic steel sheet described later.
The number of fixed magnetic poles 120 in the stator 100 in the present embodiment is 42. In addition, the number of permanent magnets 220 and rotating magnetic poles 210 of the rotor 200 in this embodiment is 56 poles, respectively. Reference numeral 260 denotes a molding resin that is filled when the rotor 200 is insert-molded in a predetermined mold.
Next, the current analysis was conducted to reduce the noise of the washing and drying machine. As a result, it was found that torque pulsation during energization is the main cause of noise increase. In other words, reducing torque pulsation is a shortcut to reducing noise.

  Therefore, in order to reduce torque pulsation, in the present invention, the position of the end of the rotating magnetic pole 210 is adjusted so as to cancel the current torque pulsation. The first rotor core 211 having a shape in which the end of the tip protrudes in the circumferential direction and the second rotor core having a shape in which the end of the tip does not protrude in the circumferential direction, which constitute the rotating magnetic pole 210 in FIG. 212 is shown.

  The first rotor core 211 and the second rotor core 212 are different from each other in the radially outer shape facing the stator 100. One end of the first rotor core 211 on the outer diameter side has a protruding portion 211 a and a protruding portion 211 b that protrude on both sides in the circumferential direction. The other end of the rotor core 212 on the outer diameter side has shapes 212 a and 212 b that do not have a circumferential protrusion.

  Next, FIG. 5 shows a configuration in which the rotating magnetic pole 210 is arranged so as to cancel the torque pulsation. A first rotor core 211 having a tip end protruding in the circumferential direction and a second rotor core 212 having a tip end not protruding in the circumferential direction are arranged as shown in FIG. Laminate sequentially in the direction.

  FIG. 6 is an external view of the outer periphery side of the rotor 200 as viewed from the stator 100 side. In this embodiment, the rotating magnetic pole 210 is configured by alternately stacking the region where the first rotor core 211 is stacked and the region where the second rotor core 212 is stacked alternately in the axial direction.

  FIG. 7 shows a torque waveform diagram during dehydration. The pulsation torque of the second rotor core 212 having a shape in which the end of the tip does not protrude in the circumferential direction is different from the pulsation torque of the first rotor core 211 having a shape in which the end of the tip protrudes in the circumferential direction. The torque pulsation of the composite waveform can be reduced by canceling each other's torque by reversing about 180 °.

  FIG. 8 shows a torque waveform comparison during dehydration. Compared to the pulsating torque during dehydration of the rotor composed of the first rotor core 211 having a shape in which the magnetic steel sheet constituting the rotating magnetic pole 210 is laminated and the end of the tip protrudes in the circumferential direction. , A first rotor core 211 having a tip end protruding in the circumferential direction and a second rotor core 212 having a tip end protruding in the circumferential direction are combined according to the law. It can be seen that the pulsation torque during dehydration is reduced.

  By providing the electric motor using the rotor according to the present invention, it is possible to reduce the noise of the washing / drying machine.

  In this embodiment, a rotor using a permanent magnet is used. However, a rotor may be formed using a magnet element before magnetization, and then the magnet element may be magnetized to form a permanent magnet. In this case, since the magnet element is not magnetized when the rotor is assembled, it is not attracted to the rotating magnetic pole, and the workability can be improved.

  The electric motor using the rotor according to the present invention has been described in detail with reference to the best mode and examples. Needless to say, the contents of the present invention are not limited to the above-described embodiments, and can be appropriately modified or changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Electric motor 100 Stator 110 Stator coil 120 Fixed magnetic pole 121 Stator core tip part 200 Rotor 210 Rotating magnetic pole 211 The 1st rotor core 211a of the shape where the edge part of the front-end | tip protrudes in the circumferential direction End projecting portion 211b at the front end End projecting portion at the front end of the first rotor core 212 Second rotor core 212a having a shape in which the end at the front end does not project in the circumferential direction 212a Second end of the rotor core 211b Second Rotor core tip end portion 220 Permanent magnet 260 Molded resin material 300 Stator base 300a Flange portion 300b Body portion 310 Boss portion 311 Water seal 313a Bearing 313b Bearing 314 Nut 315 Screw 316 Flange 320 Rotating shaft 400 Washer / dryer 401 Housing 402 Base 403 Door 404 Drum 405 Outer tank 406 Side plate 4 7 rear cover 408 opening 409 suspension 410 reinforcing member

Claims (5)

A stator,
A rotor provided to rotate with respect to the stator,
The rotor is
Rotating magnetic poles with laminated magnetic steel rotor cores;
A permanent magnet disposed on both sides of the rotating magnetic pole,
It is fixed by arranging a plurality of these in an annular shape and covering the whole with a resin material,
A rotor in which a shaft connecting member is provided via a reinforcing member on an inner diameter side of the rotating magnetic pole and the permanent magnet,
The front rotating magnetic pole
A first rotor core having a projecting portion projecting in the circumferential direction at an outer diameter side end portion and a second rotor core having no projecting portion at an outer diameter side end portion are laminated. An electric motor characterized by comprising. A stator,
A rotor that rotates relative to the stator;
The rotor has an annular shape in which a plurality of permanent magnets and rotating magnetic poles are alternately arranged radially,
The rotating magnetic pole is an electric motor constituted by fixing and laminating a rotor core of an electromagnetic steel sheet at a fastening portion,
The permanent magnet and the rotor core are
It is formed in a substantially arcuate shape, and one end in the circumferential direction has a convex curved surface portion, and the other end in the circumferential direction has a concave curved surface portion.
The rotor core includes a first rotor core having a protrusion protruding in a circumferential direction at an outer peripheral end of the rotor;
A second rotor core that does not have a protrusion at the outer peripheral end,
The rotating magnetic pole is
An electric motor comprising the first rotor core and the second rotor core stacked alternately in the axial direction. The electric motor according to claim 1 or 2,
The rotating magnetic pole is
A first block in which the first rotor cores are laminated;
A second block in which the second rotor cores are laminated;
An electric motor that is configured by alternately laminating in the direction of the rotation axis.   4. The electric motor according to claim 3, wherein the second block is arranged in a rotation axis direction so as to sandwich the first block.   5. A washing machine to which the electric motor according to claim 1 is applied.

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