JP2005287296A - Permanent magnet type rotary electric machine and electric vehicle using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type rotary electric machine for preventing the heat demagnetization of a permanent magnet, which is light in weight and small in size, and has high torque. <P>SOLUTION: Side rings 81 are mounted at both axial ends of a rotor core 4 having the built-in permanent magnet 6 arranged circumferentially thereof, the outside diameter of the side ring 81 is smaller than that of a rotor. In this way, an eddy current generated in the side ring 81 is suppressed to prevent abnormal heating, so that the heat demagnetization of the permanent magnet can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small, lightweight, high-torque permanent magnet rotating electric machine used at high temperatures and an electric vehicle using the same.

  The drive motor used in an electric vehicle, particularly an electric vehicle, is small and lightweight because the amount of battery loaded as an electric vehicle is limited and it is necessary to secure a sufficient charging distance with the amount of battery. High efficiency is desired.

  In order to make the electric motor small and light, it is required to be suitable for high-speed rotation. Further, as a high efficiency motor, a permanent magnet motor can be recommended rather than a DC motor or an induction motor. In particular, a steel plate having a higher permeability than the permanent magnet compared to the surface magnet motor in which the permanent magnet is arranged on the outer periphery of the rotor, for example, a so-called internal magnet motor having a permanent magnet holding part in a silicon steel plate is suitable. Yes. This is because the internal magnet motor can be operated at a high speed by field weakening control and can be operated at high efficiency by field weakening control.

Further, the rotor of this shape has high reliability in high-speed rotation because the rotational strength is determined by the strength of the silicon steel plate as compared with the surface magnet motor. Patent Document 1 is disclosed as a conventional example of this method.
Japanese Patent Laid-Open No. 3-138050

  According to the above disclosed example, the permanent magnet is disposed in the rotor core made of a magnetic material having a higher magnetic permeability than the permanent magnet, and the auxiliary magnetic pole composed of the permanent magnet and the rotor core in the circumferential direction. The juxtaposed configuration is shown. By arranging a permanent magnet in a rotor core made of a magnetic material having a higher magnetic permeability than a permanent magnet, such as an arc, that is, an internal magnet configuration enables field weakening, high efficiency and high speed. Operation to the area becomes possible.

  However, in the case of the configuration of the above disclosed example, no consideration is given to the axial fixing method of the magnet, particularly the axial fixing method. In the disclosed example, it is described that the magnet is bonded in the hole. However, in the case of a rotating electrical machine that is operated at a high temperature, there is a possibility that the magnet may protrude in the axial direction due to a decrease in the bonding strength only by bonding.

  Therefore, a method is adopted in which a magnet retaining plate (hereinafter referred to as a side ring) or the like is formed at both ends of the rotor. A non-magnetic material is used for the side ring to prevent a short circuit of magnetic flux. However, when the side ring is made of a metal material, it has conductivity, so an eddy current is generated in the side ring due to a change in the magnetic flux from the stator winding, and abnormal heating occurs. This heat may cause the magnet to demagnetize at high temperature.

  An object of the present invention is to provide a permanent magnet type rotating electrical machine having a small size and light weight and high torque, which prevents thermal demagnetization of the permanent magnet, and an electric vehicle using the same.

  In order to achieve the above object, the permanent magnet type rotating electric machine according to the present invention is characterized in that the outer diameter of the contact plates attached to both ends in the axial direction of the rotor core is smaller than the outer diameter of the rotor. Thus, the generation of eddy current in the contact plate due to the magnetic flux from the stator winding is suppressed.

  Specifically, the present invention provides the following permanent magnet type rotating electrical machines.

  The present invention relates to a stator core having a stator core around which a stator winding is wound, and a rotor core in which permanent magnets are arranged and built in the circumferential direction facing each other with a rotation gap on the inner peripheral surface of the stator core. And a rotor having a contact plate mounted on both ends of the rotor core in the axial direction, the outer diameter of the contact plate being smaller than the outer diameter of the rotor, and from the stator winding The present invention provides a permanent magnet type rotating electrical machine that suppresses generation of eddy currents in the contact plate due to magnetic flux.

  Preferably, the difference between the outer diameter of the rotor and the outer diameter of the backing plate is ½ or more of the difference between the inner diameter of the stator core and the outer diameter of the rotor.

  The present invention also provides a stator having a stator core wound with a stator winding, and a rotation in which a permanent magnet is arranged and built in the circumferential direction facing the stator core inner peripheral surface with a rotation gap. A stator core and a rotor having a contact plate mounted on both ends of the rotor core in the axial direction, the contact plate is formed of a metal material having an electrical resistivity of 10 μΩcm or more, and the stator winding There is provided a permanent magnet type rotating electrical machine that suppresses generation of eddy currents in the contact plate due to magnetic flux from the magnetic field.

  The present invention also provides a stator having a stator core wound with a stator winding, and a rotation in which a permanent magnet is arranged and built in the circumferential direction facing the stator core inner peripheral surface with a rotation gap. A rotor core and a rotor having a contact plate attached to both ends of the rotor core in the axial direction, the outer diameter of the contact plate is smaller than the outer diameter of the rotor, and the contact plate is electrically A permanent magnet type rotating electrical machine is provided, which is formed of a metal material having a resistivity of 10 μΩcm or more and suppresses generation of eddy currents in the contact plate due to magnetic flux from the stator winding.

  The present invention also provides a stator having a stator core wound with a stator winding, and a rotation in which a permanent magnet is arranged and built in the circumferential direction facing the stator core inner peripheral surface with a rotation gap. And a rotor having a nonmagnetic member attached to both ends of the rotor core in the axial direction, the nonmagnetic member is made of a nonmetallic material, and the magnetic flux from the stator winding is used. A permanent magnet type rotating electrical machine characterized by suppressing generation of eddy current in the contact plate is provided.

  The present invention also provides a battery for supplying a DC voltage, an inverter for converting the supplied DC voltage into an AC voltage, and a permanent magnet type rotation for outputting a driving torque for driving a vehicle by the converted AC voltage. In the electric vehicle having an electric machine, the permanent magnet type rotating electric machine includes a stator having a stator core around which a stator winding is wound, and a plurality of opposed permanent magnets having a rotation gap on an inner peripheral surface of the stator core. A rotor core having a permanent magnet arranged in the circumferential direction and a rotor having a backing plate attached to both ends of the rotor core in the axial direction. A predetermined driving torque is output by driving the wheels of the vehicle with the driving torque by suppressing the generation of eddy currents in the contact plate due to the magnetic flux from the stator winding by making it smaller than the outer diameter. Features electric car To provide.

  According to the present invention, thermal demagnetization of the permanent magnet can be prevented, so that the permanent magnet type rotating electrical machine can be reduced in size and weight and increased in torque.

  Moreover, by using the permanent magnet type rotating electrical machine of the present invention for an electric vehicle, it is useful for reducing the weight of the vehicle and improving the vehicle performance.

  Hereinafter, a permanent magnet type rotating electrical machine according to an embodiment of the present invention and an electric vehicle using the same will be described with reference to the drawings.

  FIG. 1 shows an axial section of a permanent magnet type rotating electrical machine (hereinafter abbreviated as a rotating electrical machine) according to an embodiment of the present invention, and FIG. 2 shows an AA section of FIG. The permanent magnet 6 in FIG. 2 has a fan shape, but the magnet shape is not limited to this.

  A stator 2 of the rotating electrical machine 1 includes a housing 10, a stator core 4 fixed to the inner peripheral surface of the housing 10, and a multi-layer stator winding 5 wound around the stator core 4. Has been.

  The rotor 3 includes a rotor core 8, a permanent magnet 6 inserted into a permanent magnet hole 7 provided in the rotor core 8, a rotating shaft 9, and both ends of the rotor core 8 in the direction of the rotating shaft 9. The rotor core 8 is provided and a side ring 81 that holds the permanent magnet 6. The rotating shaft 9 is rotatably supported by a bearing 12 provided on the end bracket 11. The end bracket 11 is screwed and fixed to the housing 10 on the stator 2 side.

  The side ring 81 is made of a nonmagnetic material in order to prevent a short circuit of magnetic flux generated by the permanent magnet 6. When a non-magnetic metal material is used for the side ring 81, since it has conductivity, it is affected by a change in magnetic flux generated by the stator winding 5, and an eddy current is generated in the side ring 81. Abnormal heating. This heat may be transmitted to the permanent magnet 6 and demagnetize the permanent magnet 6. Particularly, in the case of a rare earth magnet, since it has a characteristic of being easily demagnetized at a high temperature, it is necessary to prevent the side ring 81 from being heated in order to prevent a decrease in performance of the rotating electrical machine.

  Therefore, the outer diameter of the side ring 81 is made smaller than the outer diameter of the rotor 3 in order to reduce the influence of the magnetic flux change from the stator winding 5 and suppress the generation of eddy current.

  The degree of reduction should be described with reference to FIG. 3 which is an enlarged view of a portion B in FIG. 1. The difference between the outer diameter D2 of the rotor 3 and the outer diameter D3 of the side ring 81 is The difference between the inner diameter D1 and the outer diameter D2 of the rotor 3 should be ½ or more.

  The reason will be described below.

The influence of the eddy currents to the side ring 81, when considered as a force F acting between the stator 4 and the rotor 3, when the gap between the stator 4 inner and rotor 3 outer diameter is [delta] _1, the following Equation (Equation 1) holds.

F = k · 1 / δ ₁ ² (Equation 1)
k: Constant equation determined by the shape, voltage input to the stator, etc. (Equation 1) also holds for the difference δ ₂ between the outer diameter of the rotor 3 and the outer diameter of the side ring 81, so the relationship between F and δ ₂ Are summarized in the following table (Table 1).

From Table 1, δ ₂ is 1.5 times δ ₁ , that is, the difference between the outer diameter D2 of the rotor 3 and the outer diameter D3 of the side ring 81 is the difference between the inner diameter D1 of the stator 4 and the outer diameter D2 of the rotor 3. If the difference is ½ or more, the influence of the eddy current of the side ring 81 due to the magnetic flux generated by the stator 4 can be reduced to half or less.

When the eddy current is halved, the relationship between the current and the loss W (Formula 2)
W = I ² · R (Equation 2)
R: Since the electric resistance loss W becomes 1/4, the temperature rise of the side ring 81 becomes 1/4.

Thus, since the influence of the eddy current decreases in proportion to the square of the distance, the difference δ ₂ between the outer diameter of the rotor 3 and the outer diameter of the side ring 81 should be as large as possible.

  Further, the material of the side ring 81 may be non-magnetic, but a material such as copper or aluminum has a low electric resistivity, so that the current value of the eddy current becomes large. Therefore, stainless steel, which has a high electrical resistivity of 10 μΩcm or more and is a nonmagnetic metal, is preferable.

The increase in electrical resistivity means that the electrical resistance R in the following equation (Equation 3) is
I = E / R (Equation 3)
E: Since the voltage induced to the side ring becomes large, the electrical resistivity of aluminum (electric resistivity 2.8 μΩcm) and stainless steel (electric resistivity 10 μΩcm) is 3.6 times that of aluminum, and the current is 1 / 3.6, which can be reduced to 1/13 when converted to a temperature rise.

  Further, if the stainless steel material having the above two characteristics, that is, the outer diameter of the side ring 81 is smaller than the outer diameter of the rotor 3 and the electric resistivity is 10 μΩcm or more, the effect is further increased.

  Further, the side ring 81 may be made of a non-metallic material such as resin if the use temperature condition and the rotation strength of the rotating electrical machine 1 allow. In the case of a resin material, since the electrical resistivity is much larger than that of a metal material, eddy currents do not flow, and thus abnormal heating does not occur. When the resin material is configured at both ends of the rotor 3, a method of attaching a plate-like material as in the case of a metal material and a method such as a resin mold for covering both ends of the rotor 3 with a resin can be realized.

  The present invention has been described by taking an inward-rotating rotor as an example. However, even an outer-rotating rotor or the like can be applied to a rotor having a structure in which a side of a magnet is sandwiched between side rings.

  The rotating electrical machine of the present invention is effective when used as a drive motor for an electric vehicle.

  As an example of an electric vehicle using a rotating electric machine as a drive motor, the configuration of an electric automobile is shown in FIG. The DC voltage supplied from the battery 20 is converted into AC by the inverter 30, and the rotating electrical machine 10 drives the wheels of the vehicle by the control unit 40 with a predetermined torque and rotation speed.

  The rotating electrical machine of the present invention can suppress the temperature rise lower than that of the conventional rotating electrical machine, so that the size can be reduced, the mounting property to the vehicle is good, the vehicle is lighter, and the vehicle performance is improved. Can be achieved.

It is an axial sectional view of a permanent magnet type rotating electrical machine according to an embodiment of the present invention. It is AA sectional drawing of FIG. It is an enlarged view of the B section of FIG. It is a block diagram of the electric vehicle using the permanent-magnet-type rotary electric machine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotary electric machine, 2 ... Stator, 3 ... Rotor, 4 ... Stator iron core, 5 ... Stator winding, 6 ... Permanent magnet, 8 ... Rotor iron core, 81 ... Side ring, 9 ... Rotating shaft, 10 ... Housing, 11 ... End bracket, 12 ... Bearing.

Claims (2)

A stator having a stator core around which a stator winding is wound;
A rotor core having a rotation gap on the inner circumferential surface of the stator core and having a plurality of permanent magnets arranged and built in the circumferential direction, and plate-like pads attached to both ends of the rotor core in the axial direction. A rotor having a plate,
The rotor core is provided with a plurality of permanent magnet holes in the circumferential direction therein,
The permanent magnet is inserted into the permanent magnet hole, the backing plate is formed of a non-magnetic metal material, and the outside diameter of the backing plate is smaller than the outside diameter of the rotor; The difference between the outer diameter and the outer diameter of the abutting plate is ½ to 1.5 times the difference between the inner diameter of the stator core and the outer diameter of the rotor, and the shaft of the rotor core is formed. A permanent magnet type rotating electrical machine that holds both ends in the axial direction of the rotor core and both ends in the axial direction of the permanent magnet from both ends in the direction. A battery for supplying direct current;
An inverter for converting the supplied DC voltage into an AC voltage;
In the electric vehicle having a permanent magnet type rotating electrical machine that outputs a driving torque for driving the vehicle by the converted AC voltage,
The permanent magnet type rotating electrical machine is
A stator having a stator core around which a stator winding is wound;
A rotor core having a rotation gap on the inner peripheral surface of the stator core and having a plurality of permanent magnets arranged and built in the circumferential direction, and plate-like contacts installed at both axial ends of the rotor core. A rotor having a plate, and a plurality of permanent magnet holes are provided in the circumferential direction in the rotor core,
The permanent magnet is inserted into the permanent magnet hole;
The pad is made of a nonmagnetic metal material, and the outer diameter of the pad is smaller than the outer diameter of the rotor, and the difference between the outer diameter of the rotor and the outer diameter of the pad is the The difference between the inner diameter of the stator core and the outer diameter of the stator is not less than 1/2 and not more than 1.5 times, and from both axial ends of the rotor core to both axial ends of the rotor core. And holding both ends of the permanent magnet in the axial direction,
An electric vehicle that outputs a predetermined driving torque and drives wheels of the vehicle with the driving torque.

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