JP2013188075A - Rotor of permanent magnet type rotary electrical machine - Google Patents

Abstract

An object of the present invention is to provide a metallic cylindrical retaining ring for retaining a permanent magnet disposed on the outer peripheral side of a core of a rotor from the outer peripheral side, while suppressing heat generation due to eddy current loss and reducing thermal demagnetization of the permanent magnet. Provided is a surface magnet type rotor structure capable of ensuring high reliability in preventing scattering of magnets.
SOLUTION: A permanent magnet 4 in which polarities of N poles and S poles are alternately arranged is arranged on the outer peripheral surface of a rotor core 3, and a metal cylinder is provided on the outer periphery of the permanent magnet as a scattering prevention member for the permanent magnets 4. In a permanent magnet type rotating electrical machine covered with a shape retaining ring, the retaining ring is distributed in the axial direction as a divided retaining ring 6 divided into a plurality of portions in the axial direction of the rotor. It is made of a non-magnetic metal material, and further surrounds each of the divided holding rings 6 arranged in the axial direction, and binds and binds the bind tape 7 around the entire outer periphery of the rotor.
[Selection] Figure 1

Description

  The present invention relates to a rotor structure of a surface magnet type rotary electric machine in which permanent magnets are arranged on a core outer peripheral surface of a rotor.

  About the permanent magnet type rotating electric machine of the surface magnet type mentioned above, a permanent magnet placed on the outer peripheral surface of the rotor core is surrounded by a metal cylindrical holding ring called a shrink ring, and the permanent magnet A rotor structure that prevents scattering due to centrifugal force is known (see, for example, Patent Document 1 and Patent Document 2).

JP 2001-339887 A JP 2004-304943 A

  In the rotor structure disclosed in Patent Documents 1 and 2, a single metal retaining ring that covers the outer periphery of the permanent magnet covers the entire area of the permanent magnet disposed on the core peripheral surface of the rotor. It consists of a cylindrical body.

  For this reason, during operation of the rotating electrical machine, the pulsating magnetic flux distributed in the gap between the stator and the rotor is linked to the holding ring by the coil slot of the stator, and an eddy current is generated in the holding ring. The holding ring generates heat due to the loss of Joule heat, and the generated heat of the holding ring is transferred to the permanent magnet to raise the magnet temperature, which causes the magnetic characteristics of the permanent magnet to deteriorate (thermal demagnetization), thereby rotating the electric machine. There is a problem of lowering the output performance.

  The present invention has been made in view of the above points, and suppresses heat generation due to eddy current loss with respect to a metallic cylindrical holding ring that covers and holds a permanent magnet disposed on a core peripheral surface of a rotor from the outer peripheral side. An object of the present invention is to provide a rotor of a permanent magnet type rotating electrical machine having an improved assembly structure so as to reduce thermal demagnetization exerted on the permanent magnet and to ensure high reliability for preventing the permanent magnet from scattering. And

In order to achieve the above object, according to the present invention, permanent magnets in which the polarities of N poles and S poles are alternately arranged along the circumferential direction are arranged on the outer peripheral surface of the core of the rotor, In the permanent magnet type rotating electrical machine with a metal cylindrical retaining ring on the outer periphery of the permanent magnet as a scattering prevention member,
The holding ring is divided into a plurality of parts in the axial direction of the rotor and dispersedly arranged (Claim 1). Specifically, the holding ring is configured in the following manner.
(1) The split retaining ring is made of a heat-resistant and high-strength nonmagnetic metal material (claim 2).
(2) In the rotor having the above-described configuration, the split retaining rings arranged in the axial direction are collectively surrounded and bound with a bind tape around the entire outer periphery of the rotor.
(3) In the preceding items (1) to (3), the permanent magnets having different polarities are alternately arranged on the core peripheral surface of the rotor, and the rotor is used as a rotation preventing member for the magnet between adjacent permanent magnets. A lock key is provided on the core peripheral surface (claims).

  As described above, the non-magnetic retaining ring placed on the outer periphery of the permanent magnet is divided and distributed in the axial direction of the rotor, so that the current path of the eddy current flowing through each divided retaining ring is not divided. Compared to the conventional retaining ring with a single structure (see Patent Documents 1 and 2), the eddy current loss is reduced depending on the number of retaining rings and the axial width. By increasing the width of each of the divided rings, the total amount of Joule heat generated by the eddy current is reduced. Thereby, it is possible to prevent deterioration of the performance of the rotating electrical machine by suppressing the deterioration of the magnetic characteristics of the permanent magnet that rises in temperature due to the transfer of Joule heat generated in the retaining ring.

  Here, by configuring the retaining ring with a heat-resistant and high-strength nonmagnetic metal material, the mechanical strength required to prevent the permanent magnets from scattering can be secured with a thin retaining ring without magnetic influence. And the eddy current loss which generate | occur | produces in a holding ring can also be suppressed small.

  In addition, each of the divided retaining rings that are divided in the axial direction is bundled together by binding an insulating bind tape (for example, glass bind tape) around the outer periphery of the holding ring, thereby dispersing the arrangement in the axial direction of the rotor. The split ring can be fixed and supported at a fixed position so that it does not move in the axial direction, and the bind tape is more flexible than metal and can be handled and wound easily.

  For rotors with segmented permanent magnets with different polarities on the core peripheral surface, a non-rotating key is provided on the core peripheral surface of the rotor as a magnet rotation preventing member between adjacent permanent magnets. The displacement of the permanent magnet in the circumferential direction can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a structural diagram of the rotor by Example 1 of this invention, Comprising: (a) is a side view of the whole rotor, (b) is the cross-sectional enlarged view of arrow XX in (a), (c) is ( It is an enlarged view of the principal part in a). FIG. 6 is a structural diagram of a rotor according to a second embodiment of the present invention, and is a cross-sectional view corresponding to an arrow XX in FIG. 1. FIG. 6 is a structural diagram of a rotor according to a third embodiment of the present invention, and is a cross-sectional view corresponding to an arrow XX in FIG. 1.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the respective examples shown in FIGS.

  In FIGS. 1A to 1C, reference numeral 1 denotes a rotor rotating shaft, 2 denotes a bearing, 3 denotes a rotor core integral with the rotating shaft, and 4 denotes a segment-shaped permanent disposed on the peripheral surface of the rotor core 3. Magnet 5 is an adhesive in which the permanent magnet 5 is attached to the rotor core 4, 6 is a split-type holding ring that surrounds the permanent magnet 4 and covers the outer periphery thereof, and 7 is wound around the peripheral surface of the holding ring 6. Bind tape (a glass cloth impregnated with resin).

  Here, in the rotor of the illustrated example, a plurality of segment-type permanent magnets 4 are arranged in the circumferential direction and the axial direction so that the north pole and the south pole are alternately arranged with respect to the rotor core 4. A cogging torque is reduced by setting a step skew angle θ between the permanent magnet rows of the respective steps arranged in a row.

  On the other hand, the split retaining ring 6 is made of a non-magnetic heat-resistant and high-strength material having mechanical strength equivalent to, for example, SUS304 or Inconel (trade name of Special Metals Corporation). The width of the retaining ring 6 is set to be smaller than the width of the segment-type permanent magnet 4, and the rotor is matched to the position of the permanent magnet 4 in each row aligned in the axial direction of the rotor as shown in the figure. Are arranged so as to be fitted on the peripheral surface. The thickness of the retaining ring 6 is set to about 0.5 to 2 mm, for example, and is set so as to ensure mechanical strength against the centrifugal force applied to the permanent magnet 4 during operation of the rotating electrical machine.

  Further, the bind tape 7 is a glass bind tape in which a glass cloth is impregnated with an epoxy resin, and the entire length of the rotor core so as to collectively cover the divided holding rings 6 arranged in the axial direction in a semi-cured prepreg state. After being wound around the area, it is heat-cured and bound.

  With the above configuration, the eddy current flowing through each of the split holding rings 6 during operation of the rotating electrical machine is smaller than that of a single cylindrical holding ring employed in the conventional structure (see Patent Documents 1 and 2). The total eddy current loss is reduced and the Joule heat generation of the retaining ring 6 is reduced. Thereby, the thermal demagnetization of the permanent magnet 4 that receives a heat transfer from the holding ring 6 and rises in temperature can be suppressed, and a reduction in the operating performance of the rotating electrical machine can be effectively prevented.

  In the illustrated embodiment, the split-type holding ring 6 is divided (divided into three) in accordance with the arrangement of the permanent magnets 4 aligned in the axial direction (three rows in the illustrated example). Since the holding ring 6 has a smaller effect in reducing eddy current loss as the axial width is smaller, it is preferable to further divide the number of divisions of the holding ring and disperse it.

  In this embodiment, the bind tape 7 is wound around the entire area of the rotor so as to collectively cover the split-type holding rings 6 arranged in the axial direction of the rotor. It can be firmly bound and held so as not to move out of position. In addition, this glass binding tape is an insulating material that does not generate eddy currents and is flexible, so that it can be easily wound and is effective in preventing damage to the rotor.

  FIG. 2 shows an application example of the first embodiment, which is adjacent to the segment-type permanent magnet 4 arranged so that the N pole and the S pole are alternately arranged in the circumferential direction of the rotor core 4. An anti-rotation key 8 is provided on the circumferential surface of the rotor core 3 as a magnet anti-rotation member between the permanent magnets 4. Other configurations are the same as those of the first embodiment.

  With this configuration, it is possible to prevent the permanent magnet 4 from shifting from the fixed position in the circumferential direction due to the driving torque of the rotating electrical machine.

  Next, FIG. 3 shows an embodiment in which a ring-shaped permanent magnet 9 magnetized so that the polarities of the N pole and the S pole are alternately arranged on a cylindrical magnet is adopted as the permanent magnet disposed on the peripheral surface of the rotor core 3. Show. In this embodiment, a split-type holding ring 6 is put on the outer periphery of a ring-shaped permanent magnet 9 that is fitted and pasted on the peripheral surface of the rotor core 3, and then a binding tape is placed outside thereof. 7 is wound and bound. With this configuration, even if the ring-shaped permanent magnet 9 is damaged during operation of the rotating electrical machine, the magnet fragments are not scattered around.

1 Rotating shaft 3 Rotor core 4 Permanent magnet 5 Adhesive 6 Split retaining ring 7 Bind tape 8 Non-rotating key

Claims (4)

Permanent magnets in which the polarities of N poles and S poles are alternately arranged along the circumferential direction are arranged on the outer peripheral surface of the rotor core, and a metal cylinder is formed on the outer periphery of the permanent magnet as a member for preventing the permanent magnets from scattering. In a permanent magnet type rotating electrical machine covered with a retaining ring,
A rotor of a permanent magnet type rotating electric machine, wherein the holding ring is divided into a plurality of parts and distributed in the axial direction of the rotor.   2. The permanent magnet type rotating electric machine according to claim 1, wherein the split type retaining ring is a heat-resistant and high-strength nonmagnetic metal material.   3. The rotor according to claim 1, wherein each of the divided retaining rings arranged in the axial direction is collectively surrounded and bound with a binding tape around the entire outer periphery of the rotor. A rotor of a permanent magnet type rotating electrical machine.   The rotor according to any one of claims 1 to 3, wherein permanent magnets having different polarities are alternately arranged on a core peripheral surface of the rotor, and a magnet rotation-preventing member is provided between adjacent permanent magnets. A rotor of a permanent magnet type rotating electrical machine, characterized in that a rotation-preventing key is provided on the core peripheral surface of the rotor.