JP6220544B2 - motor - Google Patents

Description

  The present invention relates to a magnet holding structure of a rotor used in an electric power steering motor.

  The following patent documents are available as background art in this technical field. Patent Document 1 discloses a resin component for holding a magnet that holds a magnet by a groove provided in a rotor core, and a magnet cover made of a non-magnetic material is provided on the outermost periphery of the magnet. Patent Document 2 discloses a structure in which a resin is insert-molded so that a magnet is fixed by including a groove of a rotor core in a gap between magnets of a rotor. Patent Document 3 discloses a magnet holding member having a structure provided with a plurality of protrusions made of resin. A nonmagnetic cover is provided on the outer periphery.

Japanese Patent Laid-Open No. 11-243654 JP-A-9-19091 WO2007 / 080887 Publication

  In the patent document, there is no description using the shaft end surface of the rotor core with respect to the axial retaining of the resin member for holding the magnet, and a nonmagnetic member cover provided separately on the outer periphery of the resin holding member is used. Therefore, when a metal is used for the nonmagnetic holding member, an eddy current loss occurs in the metal cover as the rotor rotates, causing a reduction in motor efficiency and an increase in rotor temperature. As a result, a permanent magnet to be used must have high heat resistance. Improving the heat resistance of permanent magnets increases the amount of expensive rare earth elements, such as Dy (dysprosium) and Tb (terbium), and increases the cost of permanent magnets.

In order to solve the above problems, in the motor having a surface magnet type permanent magnet rotor on the surface of the motor rotor core of the present onset Ming plurality of permanent magnets are arranged, the inner periphery of the magnet cover of a cylindrical non-magnetic body The surface has a space where the permanent magnet can be arranged, and a part of the non-magnetic magnet cover is coupled to the rotor core in a state of fitting into a groove provided between the magnets on the surface of the rotor core, The space portion further includes a magnet sub-cover that is a non-magnetic material, non-conductive and springy, and fits into the groove, and is disposed between the magnet sub-cover and the magnet mounting surface of the rotor core. It has a film-like heat-shrinkable tube in which a permanent magnet is arranged and also serves to prevent the magnet cover from coming off in the axial direction .

  Preferably, in order to fill the gap between the cup-type containers, a heat-shrinkable tube such as PET is arranged on the outer periphery of the cup-type container so that the cup-type container is restrained from coming off from the rotor core in the axial direction. It is.

  In the present invention, by using a member made of a non-magnetic material and a non-conductive material as the material of the magnet cover, eddy current loss caused by the rotation of the rotor can be suppressed. Thereby, since the efficiency improvement of a motor and the temperature rise of the permanent magnet arrange | positioned at a rotor can be reduced, an inexpensive magnet can be employ | adopted for the permanent magnet to be used. Since this eddy current loss increases with the square of the rotational speed, if the rotational speed is doubled, the loss is quadrupled. Therefore, a remarkable effect can be expected in those used at high speed.

Structural diagram of an EPS motor with an integrated electromechanical structure Explanatory drawing of the motor unit shown in FIG. Rotor structure diagram of motor shown in FIG. Axial sectional view of the rotor shown in FIG. Structural diagram of the rotor core shown in FIG. Cup-shaped magnet holding member made of resin Structural diagram in which a rotor core is press-fitted into the cup-type magnet holding member shown in FIG. Bird's-eye view explaining the rotor manufacturing process Explanatory drawing showing assembly order of rotor Explanatory drawing which provided the magnet rotation suppression part in the magnet holding part of the rotor core Structure drawing produced by dividing the magnet holding member shown in FIG. Explanatory drawing which showed the other Example of the magnet rotation suppression part demonstrated in FIG. Explanatory drawing which inserts a magnet in the magnet sub cover demonstrated in FIG.

  Hereinafter, embodiments will be described with reference to FIGS.

In this embodiment, an electromechanical integrated electric power steering (abbreviated as EPS) motor structure in which the motor of the electric power steering motor and the control unit are integrated will be described.
FIG. 1 is an example illustrating the structure of the electric power steering motor of this embodiment. The electromechanical integrated EPS motor 100 includes a motor unit 101 and a control unit 102. The control unit 102 is provided with a connector 103 so that power is supplied. The control unit 102 is mounted with an inverter and a control board for driving the motor. The motor unit 101 is configured to be supplied with three-phase drive power from the control unit 102. Although not shown, an output shaft capable of outputting motor torque is provided on the right side of the motor unit 101.

  The structure of the motor unit 101 will be described in detail with reference to FIG. FIG. 2 shows a structure in which the control unit 102 of FIG. 1 described above is removed. The motor unit 101 is composed of a stator, a rotor, and a coil for configuring a motor (not shown) inside the aluminum housing 104. Electrical connection points with the control unit 102 are a U-phase terminal 108u, a V-phase terminal 108v, a W-phase terminal 108w, and a power terminal 105 for driving the relay, which are connected to the three-phase winding. Two power terminals for driving the relay are prepared so that the two relays can be controlled to open and close independently. Since this signal has a small current capacity, the ground line is a body earth. The terminal board 109 is molded from resin, and two motor relays 106a and 106b are mounted on the resin board. A resolver rotor 107 for detecting magnetic poles is provided on the motor shaft 1 at the center of the terminal board 109.

  FIG. 3 shows the rotor disposed in the central portion of the motor unit 101 described above. In this rotor, a rotor core 2 is fixed to a shaft 1 by press fitting or shrink fitting. The rotor core 2 includes a magnet holding member 4F, a magnet holding member 4R, a permanent magnet (not shown), and a rotor protection member 5 on the outer periphery thereof. In this embodiment, the magnet holding member is made of a nonmagnetic and nonconductive resin, and the rotor protection member disposed on the outer peripheral side of the magnet holding member 4 is also a nonmagnetic and nonconductive thin film. It is configured. The film is preferably a heat-resistant and heat-shrinkable material such as PET.

  Next, the details of the rotor structure will be described with reference to FIG. FIG. 4 shows an axial sectional view of the rotor described above. First, the configuration will be described. A shaft 1 is disposed in the central portion. A rotor core 2 is fixed to the shaft 1 by shrink fitting or the like. The space portion 23a cut out in the axial direction of the rotor core 2 is a hole for stealing meat for reducing the mass of the rotor core. Similarly, the through hole 23b serves as a positioning hole for a magnetizing yoke used for magnetizing the magnet. A core fitting portion 6 provided in the magnet holding members 4F and 4R is press-fitted into the space portion a. As the shape of the core fitting portion 6, a taper is provided at the tip portion so that it can be easily press-fitted. Ultimately, the design is such that there is a tightening margin other than the tapered portion at the tip of the core fitting portion 6. The magnet holding member is composed of two parts 4R that are press-fitted from the opposite side to the magnet holding member 4F that is press-fitted from the shaft output side of the motor. Further, the permanent magnet 3 is sandwiched between these magnet holding members. The rotor core 2 and the permanent magnet 3 are sandwiched between two magnet holding members, and both end surfaces of the magnet are positioned in contact with these magnet holding members. Due to the dimensional tolerances of the magnets, etc., the magnet holding member is designed to have a gap on the mating surface, and a film-like protective cover called the rotor protective member 5 is used as the outermost periphery so that the magnet chip from that portion does not pop out. Covering the side. The rotor protection member 5 has a function of not only preventing the magnet protection members 4F and 4R from coming off in the axial direction by heat shrinking not only on the outer peripheral portion of the rotating body but also on the inner peripheral side in the axial direction.

  FIG. 5 shows the structure of the rotor core 2. The rotor core 2 is obtained by punching electromagnetic steel sheets and stacking a plurality of sheets in the axial direction. As the shape of the end face in the axial direction, magnet mounting surfaces 21 on which magnets are arranged are provided at equal intervals on the entire circumference of the rotor core 2. A groove 22 is provided in the gap on the magnet mounting surface. The opening of the groove 22 is configured to be narrower than the width on the inner peripheral side. On the inner peripheral side of the rotor core 2, a space portion 23a disposed on the outer diameter side and a space portion 23b disposed on the inner peripheral side are disposed. The space 23a is provided for reducing the mass of the rotor core and reducing the moment of inertia. The space portion 23b is a through hole for polarity discrimination for magnetizing the magnet, and is provided at the same position of the magnet. In this embodiment, since ten magnets are used, the space 23b has five holes.

  FIG. 6 illustrates the structure of the magnet holding member 4 that is press-fitted into the rotor core. The magnet holding member 4 has a cup-like structure, and a plurality of groove fastening portions 7 are equally provided on the inner peripheral portion on the outer diameter side. A space portion is provided between the groove fastening portions 7 so that the permanent magnet 3 can be disposed. This space portion has a fan shape in this embodiment. A magnet abutting portion 8 for contacting the core fitting portion 6 and the permanent magnet 3 is provided on the bottom surface portion. As described above, the core fitting portion 6 has a shape in which a taper is provided at the tip portion. The core fitting portion 6 has a structure that is press-fitted into the space portion 23 a of the rotor core 2. The core fitting portion 6 may have a structure in which metal or the like is embedded in order to mechanically and firmly bond with the space portion 23a of the rotor core 2.

  FIG. 7 shows a state in which the rotor core 2 shrink-fitted on the shaft 1 is press-fitted into the magnet holding member 4R. The groove fastening portion 7 of the magnet holding member 4R is fitted in the groove portion 22 of the rotor core 2. The magnet insertion portion 10 is configured in the gap between the magnet mounting surface 21 of the rotor core 2 and the magnet holding member 4R. A magnet abutting portion 8 is disposed on the axial end surface of the magnet insertion portion 10.

  The process after the process demonstrated in FIG. 7 is demonstrated using FIG. The lower part of FIG. 8 shows a state in which the rotor core 2 shrink-fitted on the shaft 1 to the magnet holding member 4R shown in FIG. 7 is press-fitted by the space 23a of the rotor core 2 and the core fitting part 6 of the magnet holding member 4R. It is. Next, the permanent magnet 3 is inserted into the magnet insertion portion 10 that becomes a gap between the magnet holding members. After the permanent magnet enters the magnet insertion part 10, the other magnet holding member 4F is similarly press-fitted into the space part 23a provided in the rotor core and the core fitting part 6 provided in the magnet holding member 4F. Each of the magnet holding members is configured to be sandwiched between the permanent magnet end face and the magnet abutting portion 8. The magnet holding member to be press-fitted first and the rotor core are in contact with each other on the surface, but the magnet holding member to be press-fitted afterwards has a magnet end face that comes into contact with the magnet abutting portion 8 first. The structure has a gap. This gap acts to absorb the thickness difference of the rotor core.

  FIG. 9 shows the order of the steps. In the work order 1, the rotor core 2 press-fitted into the shaft 1 is provided in the magnet holding member 4R and the magnet holding member 4R in accordance with the groove fastening portion 7 and the groove portion 22 from above with respect to the magnet holding member 4R. The core fitting portion 6 is press-fitted so that there is no gap. In step 2, the permanent magnet 3 is inserted into the magnet insertion part 10 manufactured in the previous step 1. At this time, the position of the permanent magnet 3 in the axial direction is determined by the magnet abutting portion 8 of the magnet holding member 4R. In the work order 3, the other magnet holding member 4F is press-fitted from above into the rotor core 2 press-fitted into the magnet holding member 4R created in the work order 2. Also in this case, the positioning in the rotational direction is determined by the groove fastening portion 7 and the groove portion 22 and is finally assembled at a position where the magnet abutting portion 8 provided on the magnet holding member 4F and the shaft end surface of the permanent magnet 3 are combined. Is completed. Although the routing 4 is not shown in the figure, the entire rotor is covered with a heat-shrinkable tube as shown in FIG.

  FIG. 10 shows a structure in which the reinforcing rotation suppressing portions 11 for reinforcing the permanent magnet 3 are provided at both ends of the magnet mounting surface 21 of the rotor core 2. Thus, the rotational force can be distributed to the core and the resin by receiving the torque in the rotational direction of the permanent magnet 3 at the end of the rotor core made of metal by the rotation suppression unit 11 provided on the rotor core. It becomes like this. As a result, the stress applied to the resin can be reduced.

  FIG. 11 shows an example of a case where the magnet holding member configured in a cup shape is divided and created. In this figure, the number of divisions is 10 on one side. The description of the figure is the same as FIG.

  FIG. 12 shows a configuration in which the rotation suppression of the magnet is configured by the magnet sub-cover 50. The magnet sub cover 50 is made of a thin material and has a structure that fits into the groove portion 22 of the rotor core 2. In this structure, the permanent magnet 3 is disposed between the magnet sub cover 50 and the magnet mounting surface 21. Ideally, a non-magnetic and non-conductive member that does not generate eddy currents on the magnet surface is good, but it is important to select a material with a large electrical resistance. Further, a material having a spring property such that the permanent magnet 3 is sandwiched between the core and the core may be used.

  FIG. 13 shows a diagram in which a magnet sub-cover 50 is disposed on the rotor core 2 in order to realize rotation suppression of the magnet, and a magnet is inserted between the magnet protective cover 50 and the rotor core 2. With the structure shown in this figure, a permanent magnet protective cover can be constructed by assembling the magnet holding members 4F and 4R described so far from the front and rear in the axial direction. In addition, by forming the rotor protection member 5 with a thin film-like heat-shrinkable tube that also serves to prevent the magnet holding member from coming off in the axial direction, the permanent magnet can be fixed and cracks can be prevented from popping out.

  As described above, in the surface magnet type motor, the magnet holding part and the rotor are formed by using a non-conductive and non-magnetic magnet cover for the purpose of fixing the permanent magnets and preventing the cracks and chips from popping out. An eddy current in the protective member can be prevented, and the motor efficiency is improved and the temperature rise of the magnet is reduced. In addition, since the rotor protective cover uses a thin film, the resin disposed on the inner periphery of the rotor protector prevents crevice and scratches by providing chamfered corners that contact the film. There is an effect that can be suppressed.

1 shaft, 2 rotor core, 3 permanent magnet, 4 magnet holding member, 4F magnet holding member, 4R magnet holding member, 5 rotor protection member, 6 core fitting part, 7 groove fastening part, 8 magnet abutting part, 10 magnet insertion 11, rotation suppression part for reinforcement, 21 magnet mounting surface, 22 groove part, 23 a space part a, 23 b space part b, 50 magnet sub-cover, 100 electromechanical integrated EPS motor, 101 motor part, 102 control part, 103 connector, 104 Aluminum housing, 105 power terminal, 106a motor relay, 106b motor relay, 107 resolver rotor, 108u u phase terminal, 108v v phase terminal, 108w w phase terminal, 109 terminal board, 2 rotor core, 3 permanent magnet, 4 permanent magnet holding member 5 Rotor protection member, 6 core fitting part, 7 groove fastening part, 8 magnet abutment DESCRIPTION OF SYMBOLS 10 Magnet insertion part, 21 Magnet mounting surface, 22 Groove part, 23a Space part a, 23b Space part b, 41 Magnet holding member, 61 Core fitting part, 71 Groove fastening part, 81 Magnet abutting part, 50 Magnet sub cover 106a Motor relay 1, 106b Motor relay 2, 107 Resolver rotor, 108u U phase terminal, 108v V phase terminal, 108w W phase terminal, 105 Relay power supply terminal, 104 Aluminum housing, 109 Terminal board

Claims (5)

In a motor having a surface magnet type permanent magnet rotor in which a plurality of permanent magnets are arranged on the surface of a rotor core,
A groove portion provided between the magnets on the surface of the rotor core, having a space portion in which the permanent magnet can be disposed on an inner peripheral surface of a cylindrical nonmagnetic magnet cover. Coupled to the rotor core in a state of being fitted to
In the space portion, a non-magnetic material that is non-conductive and springy, and further includes a magnet sub-cover that fits into the groove portion,
A permanent magnet is disposed between the magnet sub-cover and the magnet mounting surface of the rotor core,
A motor comprising a film-like heat shrinkable tube that also serves to prevent the magnet cover from coming off in the axial direction.   2. The motor according to claim 1, wherein a part of the non-magnetic magnet cover according to claim 1 is coupled to the rotor core in a state of being matched with a hole in an end surface of the rotor core.   The motor according to claim 1, wherein the magnet cover is divided into two in the axial direction. In the surface magnet type permanent magnet rotor in which a plurality of permanent magnets are arranged on the surface of the rotor core,
A state in which a space in which the permanent magnet can be disposed is provided on an inner peripheral surface of a cylindrical non-magnetic magnet cover, and a part of the non-magnetic magnet cover matches a hole in an end surface of the rotor core. Coupled to the rotor core at
In the space portion, a non-magnetic material that is non-conductive and springy, and further includes a magnet sub-cover that fits into the groove portion,
A permanent magnet is disposed between the magnet sub-cover and the magnet mounting surface of the rotor core,
A motor comprising a film-like heat shrinkable tube that also serves to prevent the magnet cover from coming off in the axial direction. Features and to makes the chromophore at the distal end over data that the bottom of the magnet cover according to claim 1 having a surface in contact with the permanent magnet.

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