JP2008301650A - Permanent magnet synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce thrust force operated on a stator of a permanent magnet synchronous motor. <P>SOLUTION: The permanent magnet synchronous motor is provided with first and second motors 1A and 1B having rotators 5 and 6 whose outer peripheral faces 9 have corn-shapes and stators 7 and 8 which surround the outer peripheral faces 9 of the rotators 5 and 6 and whose inner peripheral faces 11 are almost similar. The first and second motors 1A and 1B are arranged on the same rotation axis 4, and are symmetrically installed with respect to a face orthogonal to the rotation axis 4. The inclination in a corn shape of the first motor 1A is made opposite to that of the second motor 1B with the same inclination angles. The stators 7 and 8 are coupled so that they cannot move in an axial direction by a coupling member 15 which simultaneously receives thrust force operated on the stators 7 and 8. The rotators 5 and 6 are fitted so that they cannot rotate with respect to the rotation axis 4 and can move in the axial direction. Actuators 43 and 44 are arranged which simultaneously move the rotators 5 and 6 in the axial direction and in opposite directions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a permanent magnet synchronous motor.

In the permanent magnet synchronous motor, the outer peripheral surfaces of the rotor and the stator are formed in a cone shape, and the rotor is moved in the axial direction to change the air gap (interval) between the rotor and the stator to change the magnetism. There has been known one in which the reluctance of the road is changed so that the field can be controlled (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2005-210808

However, in the permanent magnet synchronous motor having the conventional structure, since a magnetic field is generated obliquely with respect to the rotation axis, axial component force is generated in the rotor or stator, and the rotor (rotation shaft) or stator is generated. Axial stress may be applied.
Accordingly, the present invention provides a permanent magnet synchronous motor capable of field control and reducing axial stress.

The permanent magnet synchronous motor according to the present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is a rotor (for example, described later) having an outer peripheral surface (for example, an outer peripheral surface 9 in an embodiment described later) formed in a cone shape and having a permanent magnet (for example, a permanent magnet 10 in an embodiment described later). The rotors 5 and 6) in the embodiment and the inner peripheral surface (for example, the inner peripheral surface 11 in the embodiments described later) arranged so as to surround the outer peripheral surface of the rotor are substantially similar to the cone shape of the rotor. A first electric motor (for example, a first electric motor 1A in an embodiment to be described later) and a second electric motor (for example, a stator 7 and 8 in an embodiment to be described later) formed in a shape The second electric motor 1B) in an embodiment to be described later, and the first electric motor and the second electric motor are disposed on the same rotating shaft (for example, the rotating shaft 4 in the embodiment to be described later) It is symmetrically arranged with respect to a plane perpendicular to the rotation axis, and the cone-shaped inclination of the rotor and stator of the first motor and the cone-shaped inclination of the rotor and stator of the second motor However, the tilt directions are the same and the tilt directions are opposite to each other, and the stator of the first motor and the stator of the second motor are simultaneously subjected to the axial thrust force acting on these stators. A connecting member (for example, a connecting member 15 in an embodiment described later) is connected so as not to move in the axial direction, and the rotor of the first electric motor and the rotor of the second electric motor cannot rotate with respect to the rotating shaft. A rotor actuating means (for example, an implementation described later) is attached so as to be movable in the axial direction and moves both the rotor of the first electric motor and the rotor of the second electric motor simultaneously in the opposite directions in the axial direction. In the example Permanent magnet synchronous motor, characterized in that it comprises an actuator 43, 44) (for example, a permanent magnet synchronous motor 1) in Examples described later.

With this configuration, the rotor of the first motor is fixed to the rotor of the first motor by moving the rotor of the first motor and the rotor of the second motor in the opposite directions in the axial direction by the rotor actuating means. The distance between the first motor and the second motor can be changed at the same time, and the reluctance of the magnetic paths of the first motor and the second motor can be simultaneously changed. it can.
In addition, the first motor and the second motor are arranged symmetrically, and the inclinations of the cone shapes of the first motor and the second motor are the same, and the tilt directions are opposite to each other. And since the stator of the 1st electric motor and the stator of the 2nd electric motor are immovably connected by the connecting member, the thrust force which acts on the stator of the 1st electric motor, and fixation of the 2nd electric motor Thrust force acting on the child is canceled in the connecting member.

  The invention according to claim 2 is a rotor (for example, described later) having an outer peripheral surface (for example, an outer peripheral surface 9 in an embodiment described later) formed in a cone shape and having a permanent magnet (for example, a permanent magnet 10 in an embodiment described later). The rotors 5 and 6) in the embodiment and the inner peripheral surface (for example, the inner peripheral surface 11 in the embodiments described later) arranged so as to surround the outer peripheral surface of the rotor are substantially similar to the cone shape of the rotor. A first electric motor (for example, a first electric motor 1A in an embodiment to be described later) and a second electric motor (for example, a stator 7 and 8 in an embodiment to be described later) formed in a shape The second electric motor 1B) in an embodiment to be described later, and the first electric motor and the second electric motor are disposed on the same rotating shaft (for example, the rotating shaft 4 in the embodiment to be described later) It is symmetrically arranged with respect to a plane perpendicular to the rotation axis, and the cone-shaped inclination of the rotor and stator of the first motor and the cone-shaped inclination of the rotor and stator of the second motor However, the inclination directions are the same and the inclination directions are opposite to each other, the rotor of the first motor and the rotor of the second motor are fixed to the rotating shaft, and the stator of the first motor And a stator actuating means (for example, an actuator 45 in an embodiment to be described later) for moving both the stator of the second motor and the stator of the second motor simultaneously in the opposite directions in the axial direction. This is a permanent magnet synchronous motor 1) in an embodiment described later.

With this configuration, the stator actuating means moves the stator of the first motor and the stator of the second motor in the opposite directions in the axial direction, thereby fixing the rotor of the first motor. The distance between the first motor and the second motor can be changed at the same time, and the reluctance of the magnetic paths of the first motor and the second motor can be simultaneously changed. it can.
In addition, the first motor and the second motor are arranged symmetrically, and the inclinations of the cone shapes of the first motor and the second motor are the same, and the tilt directions are opposite to each other. And since the rotor of the 1st electric motor and the rotor of the 2nd electric motor are being fixed to the rotating shaft, it acts on the rotor of the 1st electric motor and the rotor of the 2nd electric motor. The thrust force to be canceled out at the rotating shaft.

According to the first aspect of the present invention, the thrust force acting on the stator of the first electric motor and the thrust force acting on the stator of the second electric motor are canceled by the connecting member, so that the distortion of each stator is reduced. Can be reduced.
According to the second aspect of the present invention, the thrust force acting on the rotor of the first motor and the thrust force acting on the rotor of the second motor cancel each other out on the rotating shaft, so that the distortion of the rotating shaft is reduced. can do. As a result, when the output transmission gear is provided on the rotating shaft of the electric motor, the meshing of the gear is stabilized, and the durability of the bearing supporting the rotating shaft is improved.

Embodiments of a permanent magnet synchronous motor according to the present invention will be described below with reference to the drawings of FIGS.
<Example 1>
First, a permanent magnet synchronous motor according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
As shown in FIGS. 1 and 2, the permanent magnet synchronous motor 1 includes a single rotating shaft 4 rotatably mounted by bearings 2 and 3 in the same casing (not shown), and the rotating shaft 4 in the axial direction. Two rotors 5, 6 mounted side by side and stators 7, 8 arranged outside the rotors 5, 6 are provided. The rotor 4, the rotor 5, and the stator 7 1A is constituted, and the second electric motor 1B is constituted by the rotating shaft 4, the rotor 6 and the stator 8. In other words, the first electric motor 1 </ b> A and the second electric motor 1 </ b> B are arranged on the rotation shaft 4 that is the same output shaft, and are arranged symmetrically with respect to a plane orthogonal to the rotation shaft 4.

The rotors 5 and 6 cannot be rotated in the circumferential direction of the rotating shaft 4 by a spline mechanism (not shown) provided between the rotating shaft 4 and the rotors 5 and 6, and the axial direction of the rotating shaft 4. It is attached to the rotating shaft 4 so as to be movable. In the following description, “axial direction” refers to the axial direction of the rotating shaft 4.
The outer surfaces 9 of the rotors 5 and 6 are formed in a cone shape, the cone-shaped inclination of the rotor 5 (the inclination of the outer peripheral surface 9 of the rotor 5 with respect to the axis of the rotating shaft 4) and the cone-shaped inclination of the rotor 6. (The inclination of the outer peripheral surface 9 of the rotor 6 with respect to the axis of the rotating shaft 4) is set to have the same inclination angle, but the inclination directions are opposite to each other. Are arranged adjacent to each other. That is, the outer peripheral surfaces 9 of the rotors 5 and 6 each have a cone shape whose diameter decreases as it goes outward in the axial direction. The rotors 5 and 6 have the same size.

  The rotors 5 and 6 are moved in the axial direction by actuators (rotor actuating means) 43 and 44. The actuators 43 and 44 are constituted by, for example, pistons / cylinders or stepping motors, and the pistons 41 and 42 are linked to the small diameter side end portions 20 and 21 of the rotors 5 and 6. The actuators 43 and 44 can control the expansion / contraction lengths of the pistons 41 and 42, and by moving the pistons 41 and 42, the rotors 5 and 6 are moved toward each other along the axial direction or separated from each other. Move it in the direction you want. The actuators 43 and 44 are synchronously controlled by a control device (not shown), and the rotors 5 and 6 can be simultaneously moved by the same dimension. The actuators 43 and 44 are configured to move the rotors 5 and 6 in the axial direction without interfering with the rotation of the rotors 5 and 6.

  As shown in FIG. 3, a plurality of plate-like permanent magnets 10 that are long in the axial direction and thin in the radial direction are arranged on the outer peripheral portions of the rotors 5 and 6 along the outer peripheral surface 9. Buried.

  The stators 7 and 8 are arranged so as to surround the outer peripheral surface 9 of the rotors 5 and 6, respectively. As shown in FIG. 3, the stators 7 and 8 are configured such that a plurality of teeth portions 13 project radially inward from a cylindrical yoke portion 12, and windings 14 are wound around the teeth portions 13. The tip surface of the teeth portion 13 faces the outer peripheral surface 9 of the rotors 5 and 6 via a gap. Hereinafter, the front end surface of the teeth portion 13 is referred to as the inner peripheral surface 11 of the stators 7 and 8.

  As shown in FIGS. 1 and 2, the inner peripheral surfaces 11 of the stators 7 and 8 are formed in a shape substantially similar to the cone shape of the rotors 5 and 6. That is, the cone-shaped inclination of the stator 7 (inclination of the inner peripheral surface 11 of the stator 7 with respect to the axis of the rotating shaft 4) and the cone-shaped inclination of the stator 8 (inner periphery of the stator 8 with respect to the axis of the rotating shaft 4). The inclination of the surface 11 is set to the same inclination angle, but the inclination directions are opposite to each other, and further, the inclination angle of the inner peripheral surface 11 of the stators 7 and 8 with respect to the axis of the rotating shaft 4 However, the inclination angle of the outer peripheral surface 9 of the rotors 5 and 6 with respect to the axis of the rotating shaft 4 is set to be substantially the same angle, and the outer peripheral surface 9 and the inner peripheral surface 11 facing each other are in a parallel relationship. . Therefore, the inner peripheral surfaces 11 of the stators 7 and 8 also have a cone shape that decreases in diameter as it goes outward in the axial direction.

The axial length of the stators 7 and 8 is longer than the axial length of the rotors 5 and 6, and is set to a length that can cover the axial movement range of the corresponding rotors 5 and 6, respectively. Has been. That is, even if the rotors 5 and 6 move to any position in the axial direction, the entire outer peripheral surface 9 of the rotors 5 and 6 is set to face the inner peripheral surface 11 of the stators 7 and 8. . The sizes of the stators 7 and 8 are set to the same size.
The stators 7 and 8 are connected to each other so as not to move relative to each other by a connecting member 15 made of a rigid body disposed outside the stators 7 and 8 and fixed to a casing (not shown).

Next, the operation of the permanent magnet synchronous motor 1 will be described. When the permanent magnet synchronous motor 1 is operated in a field weakening state, as shown in FIG. 1, the pistons 41 and 42 of the actuators 43 and 44 are extended, and the rotors of the first and second motors 1A and 1B are extended. 5 and 6 are moved toward each other. FIG. 1 shows a state in which the large-diameter ends 16 and 17 of the rotors 5 and 6 are closest to each other. At this time, the axial positions of the large-diameter ends 16 and 17 of the rotors 5 and 6 are fixed. The axial positions of the large-diameter end portions 18 and 19 of the rotors 7 and 8 substantially coincide with each other, while the small-diameter end portions 20 and 21 of the rotors 5 and 6 and the small-diameter end portions 22 and 22 of the stators 7 and 8 The axial separation dimension with respect to 23 is maximized.
In this state, the distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 is maximized, the reluctance of the magnetic path is increased, and the same state as the field weakening is obtained. Become.

On the other hand, when switching the operation of the permanent magnet synchronous motor 1 from the weak magnetic field state to the strong magnetic field state, the pistons 41 and 42 of the actuators 43 and 44 are pulled in as shown in FIG. The rotors 5 and 6 of the electric motors 1A and 1B are moved away from each other. FIG. 2 shows a state in which the large-diameter end portions 16 and 17 of the rotors 5 and 6 are spaced apart to the maximum. At this time, the axial positions of the small-diameter end portions 20 and 21 of the rotors 5 and 6 are determined. It almost coincides with the axial position of the small diameter side end portions 22 and 23 of the stators 7 and 8.
In this state, the distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 is minimized, the reluctance of the magnetic path is reduced, and the state is similar to that of the strong field. Become.

  The distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 can be freely controlled by controlling the pull-out lengths of the pistons 41 and 42 of the actuators 43 and 44. By doing so, the field strength can be controlled steplessly by appropriately changing the reluctance.

By the way, the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 each have a cone shape whose diameter decreases as it goes outward in the axial direction, so the first and second electric motors 1A. , 1B, a magnetic field is generated obliquely with respect to the rotation shaft 4, respectively, a force directed obliquely inwardly acts on the stators 7 and 8, and a force directed obliquely outwardly acts on the rotors 5 and 6.
Therefore, a thrust force acts on the stators 7 and 8 in a direction approaching each other. However, since the thrust force acting on the stators 7 and 8 is transmitted to the connecting member 15, these thrust forces are connected to the connecting member 15 by combining the electromagnetic characteristics of the first and second electric motors 1A and 1B. And the distortion of the stators 7 and 8 can be reduced or made zero.
On the other hand, since thrust forces act on the rotors 5 and 6 in directions away from each other, the rotors 5 and 6 try to move outward in the axial direction, but the actuators 43 and 44 are affected by this thrust force. The rotors 5 and 6 are prevented from moving in the axial direction.

<Example 2>
Next, a permanent magnet synchronous motor according to a second embodiment of the present invention will be described with reference to FIGS.
In the permanent magnet synchronous motor 1 of the first embodiment, the outer peripheral surfaces 9 and the stators 7 of the rotors 5 and 6 are moved by moving the rotors 5 and 6 of the first and second motors 1A and 1B in the axial direction. The distance d between the inner peripheral surface 11 and the inner peripheral surface 11 is changed to change the field strength. However, in the permanent magnet synchronous motor 1 according to the second embodiment, the rotor 5 of the first and second motors 1A and 1B is changed. , 6 are disabled in the axial direction, and the same action as in the first embodiment is obtained by moving the stators 7, 8 in the axial direction.
Hereinafter, the same configurations as those of the permanent magnet synchronous motor 1 of the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and the permanent magnet synchronous motor 1 of the second embodiment is different from that of the first embodiment. Will be described in detail.

In the permanent magnet synchronous motor 1 of the second embodiment, the rotors 5 and 6 of the first and second motors are fixed to the rotating shaft 4 so as not to move in the circumferential direction and the axial direction.
The stators 7 and 8 of the first and second electric motors 1A and 1B are attached to a casing (not shown) so as to be immovable in the circumferential direction and movable in the axial direction. The stators 7 and 8 can be moved in the axial direction by an actuator (stator operating means) 45. The actuator 45 is disposed between the stators 7 and 8 and is constituted by, for example, a pair of arms 46 and 47 and a stepping motor (not shown) that opens and closes the arms 46 and 47, and the distal ends of the arms 46 and 47 are arranged. The large diameter side end portions 18 and 19 of the stators 7 and 8 are linked. The actuator 45 is controlled by a control device (not shown), and can simultaneously open and close the arms 46 and 47 by the same size, and by opening and closing the arms 46 and 47, the stators 7 and 8 approach each other along the axial direction. Or move away from each other.

When the permanent magnet synchronous motor 1 of the second embodiment is operated in a field weakening state, as shown in FIG. 4, the arms 46 and 47 of the actuator 45 are opened, and the first and second motors 1A and 1B are opened. The stators 7 and 8 are moved away from each other. FIG. 4 shows a state in which the large-diameter side end portions 18 and 19 of the stators 7 and 8 are spaced apart to the maximum. At this time, the small-diameter side end portions 22 and 23 of the stators 7 and 8 are the rotors 5 and 6. Projecting outward in the axial direction from the small-diameter side end portions 20 and 21, the projecting dimension is maximized. On the other hand, the large-diameter side end portions 16 and 17 of the rotors 5 and 6 protrude from the large-diameter side end portions 18 and 19 of the stators 7 and 8, respectively, and the projecting dimension is maximized.
In this state, the distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 is maximized, the reluctance of the magnetic path is increased, and the same state as the field weakening is obtained. Become.

On the other hand, when switching the operation of the permanent magnet synchronous motor 1 from the weak magnetic field state to the strong magnetic field state, the arms 46 and 47 of the actuator 45 are closed, as shown in FIG. The stators 7 and 8 of 1A and 1B are moved in directions approaching each other. FIG. 5 shows a state in which the large-diameter end portions 18 and 19 of the stators 7 and 8 are brought closest to each other. At this time, the axial positions of the large-diameter end portions 18 and 19 of the stators 7 and 8 are rotated. The axial positions of the small-diameter side ends 22 and 23 of the stators 7 and 8 are substantially the same as the axial positions of the large-diameter end parts 16 and 17 of the rotors 5 and 6. 20 and 21 substantially coincide with the axial position.
In this state, the distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 is minimized, the reluctance of the magnetic path is reduced, and the state is similar to that of the strong field. Become.

  In addition, by controlling the opening and closing angles of the arms 46 and 47 of the actuator 45, the distance d between the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 can be freely controlled. By doing so, the field strength can be controlled steplessly by appropriately changing the reluctance.

  Also in the permanent magnet synchronous motor 1 according to the second embodiment, a thrust force acts on the rotors 5 and 6 in directions away from each other. However, since the thrust force acting on the rotors 5 and 6 is transmitted to the rotating shaft 4, these thrust forces are applied to the rotating shaft 4 by combining the electromagnetic characteristics of the first and second electric motors 1A and 1B. The distortion of the rotary shaft 4 can be reduced or reduced to zero. As a result, for example, when an output transmission gear is provided on the rotating shaft 4 of the permanent magnet synchronous motor 1, the meshing of the gear can be stabilized, and the durability of the bearings 2 and 3 is improved.

  On the other hand, since thrust forces act on the stators 7 and 8 in directions approaching each other, the stators 7 and 8 try to move inward in the axial direction, but the arms 46 and 47 of the actuator 45 The stators 7 and 8 are prevented from moving in the axial direction against the thrust force.

  In the first and second embodiments described above, the outer peripheral surface 9 of the rotors 5 and 6 and the inner peripheral surface 11 of the stators 7 and 8 have a linear cone shape. However, as shown in FIG. The inner peripheral surface 11 can also have a curved cone shape such as a parabola or an arc.

It is sectional drawing which shows the usage type in a weak magnetic field in Example 1 of the permanent-magnet synchronous motor which concerns on this invention. It is sectional drawing which shows the usage type in a strong magnetic field in the permanent-magnet synchronous motor of the said Example 1. FIG. It is the end view seen from the axial direction one side of the permanent-magnet synchronous motor of the said Example 1. FIG. It is sectional drawing which shows the usage type in a weak magnetic field in Example 2 of the permanent-magnet synchronous motor which concerns on this invention. It is sectional drawing which shows the usage type in a strong magnetic field in the permanent-magnet synchronous motor of the said Example 2. FIG. It is sectional drawing in the other Example of the permanent magnet synchronous motor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Permanent magnet synchronous motor 1A 1st electric motor 1B 2nd electric motor 4 Rotating shafts 5, 6 Rotors 7, 8 Stator 9 Outer peripheral surface 10 Permanent magnet 11 Inner peripheral surface 15 Connecting members 43, 44 Actuator (rotor operating means )
45 Actuator (stator actuating means)

Claims (2)

A rotor having an outer peripheral surface formed in a cone shape and having a permanent magnet, and a stator arranged so as to surround the outer peripheral surface of the rotor and having an inner peripheral surface formed substantially similar to the cone shape of the rotor A first electric motor and a second electric motor each having
The first electric motor and the second electric motor are arranged on the same rotation axis, and are arranged symmetrically with respect to a plane orthogonal to the rotation axis,
The inclination of the cone shape of the rotor and the stator of the first electric motor and the inclination of the cone shape of the rotor and the stator of the second electric motor are made opposite to each other with the same inclination angle. ,
The stator of the first electric motor and the stator of the second electric motor are connected so as to be immovable in the axial direction by a connecting member that simultaneously receives axial thrust force acting on the stator,
The rotor of the first motor and the rotor of the second motor are attached so as to be non-rotatable with respect to the rotating shaft and movable in the axial direction,
A permanent magnet synchronous motor comprising: rotor operating means for simultaneously moving both the rotor of the first motor and the rotor of the second motor in the opposite directions in the axial direction. A rotor having an outer peripheral surface formed in a cone shape and having a permanent magnet, and a stator arranged so as to surround the outer peripheral surface of the rotor and having an inner peripheral surface formed substantially similar to the cone shape of the rotor A first electric motor and a second electric motor each having
The first electric motor and the second electric motor are arranged on the same rotation axis, and are arranged symmetrically with respect to a plane orthogonal to the rotation axis,
The inclination of the cone shape of the rotor and the stator of the first electric motor and the inclination of the cone shape of the rotor and the stator of the second electric motor are made opposite to each other with the same inclination angle. ,
The rotor of the first motor and the rotor of the second motor are fixed to the rotating shaft,
A permanent magnet synchronous motor comprising stator operating means for simultaneously moving both the stator of the first motor and the stator of the second motor in the axial direction in opposite directions.

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