JP5673438B2 - Rotor structure of rotating electrical machine - Google Patents

Description

  The present invention relates to a rotor structure of a rotating electrical machine in which a magnet is disposed on a rotor core.

  In a rotating electrical machine in which a magnet is disposed on a rotor core, there is a technology that suppresses the induced voltage generated in the stator winding by reducing the magnetic flux of the magnet passing through the stator while eliminating the need for field-weakening control when the rotor rotates at high speed. Proposed. For example, in Patent Document 1 below, movable iron cores are provided at both ends of the rotor core in the rotation axis direction, one end (radial center side) of the movable core is rotatably supported by a support member, and the other end (radially outer side) of the movable core. Is supported by a spring. The spring is accommodated in a space of a flux barrier provided in the rotor core. The flux barrier here is partially filled with a non-magnetic material so that a space remains at both ends, and one end of the spring is supported by the non-magnetic material, and the elastic force of the spring is applied to the movable iron core. It acts and can accommodate a spring in the space on both sides. In a state where the rotational speed of the rotor is low, the movable iron core is separated from the rotor core by the elastic force of the spring, and all the magnetic flux emitted from the permanent magnet of the rotor acts as a field component passing through the stator. On the other hand, when the rotational speed of the rotor reaches a certain number or more, the movable iron core comes into contact with the rotor core by the centrifugal force generated by the rotation of the rotor. As a result, a part of the magnetic flux from the permanent magnet of the rotor passes through the movable iron core, so that the magnetic flux acting as a field component is weakened, and accordingly, it is possible to make higher rotation. .

JP 2001-25190 A JP 2006-81336 A Japanese Patent Laid-Open No. 7-322584 JP-A-7-107718 JP 2002-136002 A

  In Patent Document 1, since a spring exists between the movable iron core and the rotor (nonmagnetic material), in order to make the movable iron core approach and contact the rotor in order to weaken the field magnetic flux passing through the stator, A space for accommodating the spring is required. Since it is necessary to provide the spring accommodating space in the rotor, the structure of the rotor becomes complicated and the manufacture becomes difficult. Further, since the support member rotatably supports one end (diameter center side) of the movable iron core, a member for supporting the movable iron core such as a spring is separately required.

  An object of the present invention is to reduce the magnetic flux of a magnet passing through a stator without making field weakening control unnecessary without complicating a rotor structure in which magnets are disposed on a rotor core.

  The rotor structure of the rotating electrical machine according to the present invention employs the following means in order to achieve the above-described object.

  A rotor structure of a rotating electrical machine according to the present invention includes a rotor that is disposed opposite to a stator and has a magnet disposed on a rotor core, and an end member that is provided at an outer end in the rotation axis direction of the rotor and rotates together with the rotor. The end member is a non-magnetic elastic member that has a shape in which the original shape when the rotor is stopped is inclined so as to move away from the rotor in the rotational axis direction as it extends radially outward from the radial center side, and elastic When the member is in the original shape, the elastic member is held by the elastic member in a state of being separated to the outer side in the rotation axis direction with respect to the rotor, and at the time of the predetermined high rotation of the rotor, the elastic member is caused by centrifugal force, The gist is to elastically deform the magnetic body so as to approach the rotor.

  In one embodiment of the present invention, it is preferable that the elastic member holds the magnetic body from the outer side in the rotation axis direction.

  According to the present invention, the end member including the elastic member and the magnetic body is provided at the outer end in the rotation axis direction of the rotor, so that the magnet passing through the stator is not required to control the field weakening without complicating the rotor structure. The magnetic flux can be reduced.

It is a figure which shows schematic structure of the rotary electric machine which has the rotor structure which concerns on embodiment of this invention. It is a figure explaining operation | movement of the rotary electric machine which has the rotor structure which concerns on embodiment of this invention. It is a figure which shows schematic structure of the rotary electric machine which concerns on the related technology of this invention. It is a figure which shows the other schematic structure of the rotary electric machine which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a rotating electrical machine having a rotor structure according to an embodiment of the present invention, and shows an outline of an internal configuration viewed from a direction orthogonal to a rotor rotation axis (hereinafter simply referred to as a rotation axis). The rotating electrical machine includes a stator 12 whose rotation is fixed and a rotor 14 that can rotate relative to the stator 12, and the stator 12 and the rotor 14 face each other with a predetermined minute gap in a radial direction orthogonal to the rotation axis. The rotor 14 is disposed on the inner peripheral side of the stator 12.

  The stator 12 includes a stator core 21 and a plurality of (for example, three-phase) stator windings 22 disposed on the stator core 21 along the circumferential direction thereof. The rotor 14 includes a rotor core 31 fixed to the shaft 13 and a plurality of permanent magnets 32 disposed on the rotor core 31 along the circumferential direction thereof. Each permanent magnet 32 is embedded in the rotor core 31. In the rotating electrical machine, a rotating magnetic field that rotates in the circumferential direction is formed in the stator 12 by passing an alternating current through the stator winding 22. Then, due to electromagnetic interaction (attraction and repulsion) between the rotating magnetic field generated in the stator 12 and the field magnetic flux generated in the permanent magnet 32 of the rotor 14, torque (magnet torque) is applied to the rotor 14 to cause the rotor 14 to shaft. 13 can be rotationally driven. At that time, the rotor core 31 is attracted to the rotating magnetic field generated in the stator 12, so that reluctance torque is also generated in the rotor 14 in addition to the magnet torque. In this way, the rotating electrical machine can be caused to function as an electric motor that generates power in the rotor 14 using the power supplied to the stator winding 22. On the other hand, the rotating electrical machine can also function as a generator that generates power in the stator winding 22 using the power of the rotor 14.

  In the present embodiment, the end member 42 is provided at the outer end in the rotation axis direction of the rotor 14 (rotor core 31), and the end member 42 rotates together with the rotor 14 and the shaft 13. In the example shown in FIG. 1, the end members 42 are provided at both ends of the rotor core 31 in the rotation axis direction. However, the end members 42 may be provided only at one end of the rotor core 31 in the rotation axis direction. Each end member 42 includes a nonmagnetic elastic member 44 that does not pass magnetic flux and is attached to the rotor core 31 or the shaft 13, and a magnetic body 46 that is held by the elastic member 44 and passes magnetic flux. The original shape of the elastic member 44 when the rotor 14 is stopped is such that the end portion on the radial center side contacts the rotation axis direction end surface 14 a of the rotor 14 (rotor core 31), and the end portion on the radially outer side is the rotation axis of the rotor 14. It has a shape that becomes a cantilever beam that is separated outward from the direction end face 14a and that is inclined so as to be separated from the rotor 14 outward in the rotational axis direction as it extends radially outward from the radial center. The elastic member 44 is integrally formed from the radially central end to the radially outer end, has elasticity in the bending direction, and can be elastically deformed in the bending direction so that it can return to its original shape. It is. As a material of the integral elastic member 44, for example, resin, stainless steel (SUS), aluminum, or the like can be used. When the elastic member 44 is in the original shape (when the rotor 14 is stopped), the magnetic body 46 is held by the elastic member 44 so as to be separated from the rotor 14 outward in the rotation axis direction. It is held at the radially outer end. In the example shown in FIG. 1, the elastic member 44 holds the magnetic body 46 from the outside in the rotation axis direction. The length x of the magnetic body 46 in the extending direction of the elastic member 44 is longer than the thickness t of the permanent magnet 32.

  As shown in FIG. 2, when the rotor 14 is at a predetermined high rotational speed, the integral elastic member 44 serving as a cantilever is elastically deformed from the original shape in the bending direction by the centrifugal force acting on the end member 42. The radially outer end of the elastic member 44 moves radially outward with the magnetic body 46 as a weight, and approaches the rotational axis direction end surface 14a of the rotor 14 (the rotational axis direction end surface of the permanent magnet 32). Move inward in the rotation axis direction. As a result, when the magnetic body 46 approaches and contacts the end surface 14a of the rotor 14 in the rotation axis direction, a part of the magnetic flux from the N pole of the permanent magnet 32 is passed through the magnetic body 46 as shown by an arrow B in FIG. A short-circuit magnetic path for returning to the south pole of the permanent magnet 32 is formed at the outer end in the rotation axis direction of the rotor 14. At that time, by adjusting the bending rigidity (elastic coefficient in the bending direction) of the elastic member 44, the relationship between the position of the magnetic body 46 (distance from the end surface 14a in the rotation axis direction of the rotor 14) relative to the rotational speed of the rotor 14 is achieved. It is possible to adjust the predetermined high rotational speed of the rotor 14 when the magnetic body 46 contacts the end surface 14a of the rotor 14 in the rotation axis direction. Further, when the magnetic body 46 is in contact with the end surface 14 a of the rotor 14 in the rotation axis direction (the state shown in FIG. 2), the magnetic body 46 faces the end surface in the rotation axis direction of the permanent magnet 32 and is more magnetic than the permanent magnet 32. The position at which the magnetic body 46 is held by the elastic member 44 is determined so that 46 protrudes to both the central side and the outer side with respect to the radial direction. As indicated by an arrow B in FIG. 2, as indicated by an arrow A in FIG. 2, the magnetic flux of the permanent magnet 32 flows through a short circuit magnetic path by the magnetic body 46 near the outer end in the rotation axis direction of the rotor 14. The magnetic flux of the permanent magnet 32 interlinking with the stator winding 22 is reduced. Thus, the induced voltage generated in the stator winding 22 can be suppressed without performing field-weakening control, and high rotation with the same power supply voltage can be realized. Since the field weakening control is not required, it is possible to achieve high efficiency and simplified control of the rotating electrical machine.

  On the other hand, when the rotor 14 is stopped or at a low rotation speed, no centrifugal force acts on the end member 42 or the centrifugal force acting on the end member 42 is small. Therefore, as shown in FIG. The outer end in the direction moves radially inward using the magnetic body 46 as a weight, and moves outward in the rotational axis direction away from the rotational axis end surface 14a of the rotor 14. That is, the elastic member 44 returns to the original shape without substantially deforming. In the original shape, the magnetic body 46 is separated from the end surface 14a of the rotor 14 in the rotation axis direction, and therefore, a short-circuit magnetic path is not formed at the outer end of the rotor 14 in the rotation axis direction. As a result, as indicated by an arrow A in FIG. 1, the magnetic flux of the permanent magnet 32 is linked to the stator winding 22 near the outer end in the rotation axis direction of the rotor 14, and the permanent magnet 32 linked to the stator winding 22 Magnetic flux increases. As a result, the torque acting between the stator 12 and the rotor 14 can be increased.

  In the rotor structure of Patent Document 1 described above, as shown in FIG. 3, a spring 48 exists between the magnetic body (movable iron core) 46 and the rotor 14 (nonmagnetic body 47). In order to approach and contact 14, a space 49 for housing the spring 48 is required inside the rotor 14. Since it is necessary to provide the accommodation space 49 of the spring 48 in the rotor 14, the structure of the rotor 14 needs to be changed, and the structure of the rotor 14 becomes complicated and difficult to manufacture. On the other hand, in the present embodiment, as shown in FIG. 4, there are no other parts such as the spring 48 between the magnetic body 46 and the rotor 14, and an accommodation space 49 for other parts such as the spring 48 is provided. Since it is unnecessary, there is no need to change the structure of the rotor 14, and manufacturing is facilitated by simply attaching the end member 42 (the elastic member 44 and the magnetic body 46) to the outer end in the rotational axis direction of the rotor 14. Therefore, the magnetic flux of the permanent magnet 32 passing through the stator 12 can be reduced while making field weakening control unnecessary without complicating the rotor structure. Further, if the elastic member 44 that holds the magnetic body 46 and elastically deforms is made of a plurality of parts, a dimensional error is likely to occur between the plurality of parts or between the plurality of parts and other parts, which affects the rotation performance and deformation. In contrast, in the present embodiment, the influence can be reduced by integrally forming the elastic member 44 from the radial center end to the radial outer end.

  In the rotor structure disclosed in Patent Document 2, a plurality of slits are formed in the rotor core substantially in parallel with the magnetic flux of the permanent magnet, and a magnetic body is movably mounted in the slit. Therefore, since it is necessary to increase the gap (slit) in the rotor core, the gap interferes with the magnetic flux of the magnet, and the performance of the rotating electrical machine is degraded. On the other hand, in this embodiment, since the movable region of the magnetic body 46 is outside the rotor 14 (rotor core 31), there is no need to increase the gap inside the rotor core 31, and the performance of the rotating electrical machine does not deteriorate.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  12 Stator, 13 Shaft, 14 Rotor, 21 Stator core, 22 Stator winding, 31 Rotor core, 32 Permanent magnet, 42 End member, 44 Elastic member, 46 Magnetic body.

Claims (2)

A rotor disposed opposite to the stator and having a magnet disposed on the rotor core;
An end member provided at an outer end of the rotor in the rotation axis direction and rotating together with the rotor;
With
The end member is
A non-magnetic elastic member that exhibits a shape in which the original shape at the time of stopping of the rotor is inclined so as to be separated from the rotor outward in the rotational axis direction as it extends radially outward from the radial center;
When the elastic member has an original shape, a magnetic body held by the elastic member in a state separated from the rotor outward in the rotation axis direction;
Including
A rotor structure of a rotating electrical machine in which an elastic member is elastically deformed so as to approach a rotor by a centrifugal force when the rotor rotates at a predetermined high speed. The rotor structure of the rotating electrical machine according to claim 1,
The elastic member is a rotor structure of a rotating electric machine that holds a magnetic body from the outside in the rotation axis direction.

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