JP5212862B2 - Permanent magnet type rotating electric machine - Google Patents

Description

  The present invention relates to a permanent magnet type rotating electrical machine, and more particularly to a permanent magnet type rotating electrical machine having a rotor that reduces the influence of leakage magnetic flux.

A conventional permanent magnet type rotating electric machine has a structure as shown in FIG. 3 (see Patent Document 1). That is, the stator 1 of the permanent magnet type rotating electric machine forms a stator core 3 by laminating magnetic steel plates, and the laminated magnetic steel plates are pressed by the presser plate 5. The armature winding 4 is housed in the stator core 3 in a slot (not shown) formed so as to penetrate in the axial direction. On the other hand, the rotor 2 has a holding ring 7 welded to the shaft 6 by welding or the like so as to cover the periphery of the shaft 6, and a permanent magnet 8 a is attached to the inner periphery of the holding ring 7 instead of a magnetic field winding. Etc. are fixed by adhesion. The permanent magnet 8a is configured to be held by the holding ring 7 so as not to jump out due to centrifugal force.
JP 2004-266919 A

  Usually, as shown in the partial cross-sectional view near the end of the rotor in FIG. 3, the magnetic flux 10 a from the permanent magnet 8 a of the rotor 2 flows from the holding ring 7 to the air gap 9 between the rotor 2 and the stator 1. And enter the stator core 3. At this time, the magnetic flux 10a crosses the armature winding 4 housed in the stator core to generate a voltage. The retaining ring 7 is often made of a magnetic material in order to effectively use the magnetic flux 10a of the permanent magnet 8a. However, at the end of the rotor 2, the magnetic flux from the permanent magnet 8 a flows as a leakage magnetic flux 10 b through the magnetic material retaining ring 7 that is more likely to pass the magnetic flux than the air gap 9 that is less likely to pass the magnetic flux. There is a problem that the magnetic flux 10a incident on the three ends is reduced, and a desired voltage cannot be obtained, resulting in a decrease in performance of the rotating electrical machine.

  The present invention has been made to solve the above-described problems, and its object is to provide a permanent magnet type rotating electrical machine having a rotor configured to suppress a decrease in performance due to the influence of leakage magnetic flux. It is.

In order to achieve the above object, the invention described in claim 1 includes a stator core formed by laminating magnetic steel plates in the axial direction, a stator core presser plate for fastening and fixing the stator core, and the fixing A stator composed of armature windings housed in slots of the core core, a shaft, a cylindrical retaining ring that covers the periphery of the shaft and is joined to the shaft at an axial end, and In a permanent magnet type rotating electrical machine having a rotor composed of a permanent magnet fixed to an inner peripheral surface, the permanent magnet of the rotor is extended axially outward from the end of the stator together with the holding ring, In order to suppress the influence on the stator core due to the leakage magnetic flux flowing at the end of the retaining ring, the length of the extension should be set when the permanent magnet has a strong magnetic force or the retaining ring is thin. Shorten and keep the magnetic strength of the permanent magnet weak or retained If the thickness of the thick is characterized by longer.

  According to the permanent magnet type rotating electric machine of the present invention, the retaining ring is welded to the shaft so as to cover the periphery of the shaft, and the permanent magnet is fixed to the inner periphery of the retaining ring with an adhesive or the like. Since the permanent magnet member and the holding ring are configured to extend outward in the axial direction from the end portion of the stator core, it is possible to suppress a decrease in performance due to the influence of leakage magnetic flux.

(First embodiment)
Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of the vicinity of the end of the rotor of the permanent magnet type rotating electric machine according to the first embodiment of the present invention. The rotor of the permanent magnet type rotating electric machine of the present embodiment is the conventional permanent magnet shown in FIG. The configuration different from the rotor of the magnet-type rotating electrical machine is that a permanent magnet 8a of the rotor 2 has a permanent magnet 8b extending axially outward from the end of the stator core 3, and a holding ring for holding the permanent magnet 8b. 7 is also a point extending outward in the axial direction. Since other configurations are the same as those of the conventional permanent magnet type rotating electric machine, the same components will be described with the same symbols.

  As shown in FIG. 1, the stator 1 of the permanent magnet type rotating electric machine of the present embodiment forms a stator core 3 by laminating magnetic steel plates, and the laminated magnetic steel plates are pressed by a presser plate 5. ing. The armature winding 4 is housed in the stator core 3 in a slot (not shown) formed so as to penetrate in the axial direction. On the other hand, the permanent magnet of the rotor 2 is composed of the conventional permanent magnet 8a and the permanent magnet 8b extending outward in the axial direction from the end of the stator core 3. Therefore, the holding ring 7 holding the permanent magnet is also outward in the axial direction. It has an extended configuration. The holding ring 7 is welded to the shaft 6 by welding or the like so as to cover the periphery of the shaft 6.

  Since the present embodiment is configured as described above, the end portion of the rotor 2 tends to flow through the holding ring 7 in which the leakage magnetic flux 10b is a magnetic material as in the conventional case, but flows into the holding ring 7. The leakage magnetic flux 10b becomes the magnetic flux of the portion 8b extending outward in the axial direction from the end of the stator core 3. Therefore, even if the magnetic flux at the end of the rotor 2 becomes the leakage magnetic flux 10b and flows through the end of the retaining ring 7, the magnetic flux from the permanent magnet 8a in the rotor 2 is incident on the end of the stator core 3. A decrease in performance of the rotating electrical machine due to the influence of the magnetic flux 10b can be suppressed.

(Second Embodiment)
FIG. 2 is a cross-sectional view of the vicinity of the end of the rotor of the permanent magnet type rotating electric machine according to the second embodiment of the present invention, and the configuration different from the permanent magnet type rotating electric machine of the first embodiment of FIG. The configuration is such that the thickness of the retaining ring 7 and the length of the permanent magnet 8b extending outward in the axial direction can be adjusted. The other configuration is the same as that of the first embodiment shown in FIG. Parts will be described with the same symbols.

  As shown in FIG. 2, in the permanent magnet type rotating electric machine of the present embodiment, in the rotor 2, the thickness of the holding ring 7 is t, and the length of the permanent magnet 8 b extending outward in the axial direction is L. Here, the length L of the permanent magnet 8 b extended outward in the axial direction is adjusted by the strength of the magnetic force of the permanent magnet 8 b and the thickness t of the holding ring 7. That is, when the strength of the magnetic force of the magnet 8b is strong or the thickness t of the retaining ring 7 is thin, the end of the retaining ring is likely to be magnetically saturated, so that the strength of the magnetic force of the magnet 8b is weakened or retained. The thickness t of the ring 7 is increased. Here, the length L of the magnet 8b is adjusted to be shorter. On the contrary, if the magnet 8b has a weak magnetic force or the holding ring 7 has a large thickness t, the holding ring end portion is less likely to be magnetically saturated, so that the magnetic force of the magnet 8b is increased. Alternatively, the thickness t of the holding ring 7 is reduced. Here, the length L of the magnet 8b is adjusted to be longer. Thus, the length L of the permanent magnet 8b is adjusted according to the strength of the magnetic force of the permanent magnet 8b and the thickness t of the holding ring 7 so as to minimize the influence of the leakage magnetic flux 10b.

  As described above, according to the present embodiment, by adjusting the length L of the permanent magnet 8b, it is possible to suppress the deterioration of the performance of the rotating electrical machine due to the influence of the leakage magnetic flux 10b with the appropriate length of the permanent magnet 8b. .

FIG. 3 is a cross-sectional view of the vicinity of the end of the rotor according to the first embodiment of the present invention. Sectional drawing of the edge part vicinity of the rotor which concerns on the 2nd Embodiment of this invention. Sectional drawing of the edge part vicinity of the rotor of the conventional permanent magnet type rotary electric machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stator, 2 ... Rotor, 3 ... Stator core, 4 ... Armature winding, 5 ... Holding plate, 6 ... Shaft, 7 ... Retaining ring, 8a, 8b ... Permanent magnet, 9 ... Air gap, 10a ... magnetic flux, 10b ... leakage magnetic flux.

Claims (1)

A stator core formed by laminating magnetic steel plates in the axial direction, a stator core presser plate for fastening and fixing the stator core, and an armature winding housed in a slot of the stator core. A stator, a shaft, a cylindrical retaining ring that covers the periphery of the shaft and is joined to the shaft at an axial end, and a rotor that is fixed to an inner peripheral surface of the retaining ring. In the permanent magnet type rotating electrical machine,
Extending the permanent magnet of the rotor together with the holding ring to the outside in the axial direction from the end of the stator, so as to suppress the influence on the stator core due to leakage magnetic flux flowing through the end of the holding ring The length of the part is shortened when the magnetic force of the permanent magnet is strong or the retaining ring is thin, and the length of the part is long when the magnetic force of the permanent magnet is weak or the retaining ring is thick. A permanent magnet type rotating electrical machine.

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