JP3483786B2 - Permanent magnet type rotating electric machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed permanent magnet type rotating electric machine in which a peripheral surface of a permanent magnet is covered with a retaining ring.

[0002]

2. Description of the Related Art A conventional general permanent magnet type rotary electric machine will be described with reference to FIG. 7A is an external view of the rotor, and FIG. 8B is an enlarged cross-sectional view of the X portion of FIG. In these figures, 1 is a shaft and bearing 2
It is rotatably attached to a stator (not shown) via. Reference numeral 3 denotes a permanent magnet, and a plurality of permanent magnets having an arc-shaped cross section in a direction orthogonal to the axial direction are closely adhered to the surface of the shaft 1 in the circumferential direction. The plurality of permanent magnets 3 are magnetized to have an S pole on the inner circumference side and an N pole on the outer circumference side, and magnets magnetized in the opposite directions of the polarities of the inner and outer circumferences according to the number of poles. It is placed and generates a field. Numerals 4 and 5 are end rings, which are shrink-fitted and fixed on the shaft 1 located at both axial ends of the permanent magnet 3. Reference numeral 6 denotes a holding ring, which has a ring shape that covers the entire outer peripheral surface of the permanent magnet 3, and is shrink-fitted and fixed to the end rings 4 and 5 at both axial ends of the permanent magnet 3. A combination of the permanent magnets 3, the end rings 4 and 5, and the retaining ring 6 is attached to one or more sets in the axial direction of the shaft 1 according to the output of the permanent magnet type rotary electric machine to form the rotor 7.

In the permanent magnet type rotating electric machine constructed as described above, the rotating magnetic field generated by the stator and the field generated by the rotor 7 generate a rotating torque, and the rotor 7 rotates. At this time, the retaining ring 6 prevents the permanent magnet 3 from scattering due to the centrifugal force acting on the permanent magnet 3 due to the rotation of the rotor 7, so that the rotor 7 can rotate at high speed.

[0004]

In the conventional permanent magnet type rotating electric machine using the permanent magnet 3 as the magnetic field generating means of the rotor 7, as described above, the permanent magnet 3 is retained by the retaining ring so as not to be scattered by the centrifugal force. 6 is protected from the outer peripheral side, but the rotor 7 rotates at a high speed, and windage and eddy current loss are generated on the outer peripheral surface of the retaining ring 6, thereby causing the retaining ring 6 to rotate.
Temperature rises, and thermal elongation a occurs. However, retaining ring 6
Is the shaft 1 via the end rings 4 and 5 at both ends in the axial direction.
Since the heat expansion a in the axial direction is constrained by the shaft 1 at the "Ya" and "Yb" positions, respectively, it is fixed to the retaining ring 6 and the end rings 4, 5 by high speed rotation. When the centrifugal force acts and the restraint force decreases due to the circumferential extension of each member, and the retaining ring 6 further rises in temperature and the heat stretch a exceeds the restraint force, the heat stretch that has been suppressed until then. Is released at once, the vibration of the rotor 7 during high-speed rotation suddenly changes, and when the restraint force and the thermal expansion of the retaining ring 6 are uneven in the circumferential direction, the rotor 7 is bent (deformed) by heat. Cause Thus, the rotor 7 rotating at high speed
In addition, when there is a sudden change in vibration, heat bending, etc., the rotor 7 may be damaged or scattered.

The present invention has been made in view of the above,
With a simple structure with excellent manufacturability and assemblability, it is possible to prevent sudden vibration of the rotor due to thermal expansion of the retaining ring during rotation, heat bending, peeling of permanent magnets, etc., and stable high-speed rotation. It is an object of the present invention to provide a permanent magnet type rotating electric machine that can be operated and can improve reliability during operation.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide a stator constituted by winding an armature winding around an armature core, and to rotate the shaft center portion of the stator. In a permanent magnet type rotating electric machine having a rotor in which a plurality of field magnets are circumferentially arranged on the circumferential surface of a shaft, and a retaining ring is arranged on the surface of these permanent magnets. The gist of the present invention is that the holding ring is fitted and fixed to the shaft at a plurality of axial positions, and one position located on one side in the axial direction of the fitting and fixing portion is a support structure having elasticity in the axial direction. With this configuration, when the rotor rotates at a high speed, the temperature of the retaining ring rises due to wind loss, eddy current loss, etc. generated on the outer peripheral surface of the retaining ring, and thermal expansion occurs. By elastically deforming,
This heat expansion is absorbed.

According to a second aspect of the present invention, in the permanent magnet type rotary electric machine according to the first aspect, the fitting and fixing portion is constituted by end rings arranged on both sides in the axial direction of the permanent magnet, and the elasticity is provided. The gist of the supporting structure has is that it is configured by reducing the axial thickness of one of the end rings. With this configuration, the support structure having elasticity that absorbs the thermal expansion of the retaining ring is appropriately realized by the end ring having a reduced axial thickness.

According to a third aspect of the present invention, in the permanent magnet type rotary electric machine according to the second aspect, the axially thin end ring has a portion on the outer diameter side of the end portion of the retaining ring. The gist is to have a shape that covers a part. With this configuration, the retaining ring is radially constrained by the tensile stress of the end ring. As a result, the end ring can be made thinner without the risk of buckling of the members,
It is possible to effectively absorb the thermal elongation of the retaining ring.

According to a fourth aspect of the present invention, in the permanent magnet type rotary electric machine according to the first aspect, the fitting and fixing portion is constituted by end rings arranged on both sides in the axial direction of the permanent magnet, and the elasticity is provided. The gist of the supporting structure is that the one end ring has a comb-shaped cross section in the axial direction. With this configuration, the end ring can be set to have extremely low axial rigidity without fear of buckling of the radial member, and it is possible to effectively absorb the thermal elongation of the retaining ring. .

According to a fifth aspect of the present invention, in the permanent magnet type rotary electric machine according to the first aspect, the holding ring has an end portion,
The support structure having an elasticity is formed by forming an extension portion extending to the inner diameter side to have an L-shaped cross section in the axial direction, fitting the extension portion to the shaft to form the fitting fixing portion, and having the elasticity. The gist is that it is configured by reducing the axial thickness of the extending portion. With this configuration, it is possible to absorb the thermal expansion of the retaining ring with a simple structure.

According to a sixth aspect of the present invention, in the permanent magnet type rotary electric machine according to any one of the second to fifth aspects, the other end ring that does not form the elastic support structure scrapes the shaft. The gist is that it is formed by taking out. With this configuration, the end ring that does not form the support structure is integrated with the shaft to facilitate assembly, and enhance mechanical strength.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1 and a second embodiment to be described later, the same or equivalent members as those in FIG. 6 are designated by the same reference numerals and are duplicated. The description is omitted. First, the configuration of the present embodiment will be described with reference to FIG. 1. In the present embodiment, the end rings 4a and 5 sandwich the permanent magnet 3 in the axial direction, and the space between the permanent magnet 3 and the permanent magnet 3 is as narrow as required. It is shrink-fitted and fixed to the shaft 1 with a gap. The end ring 4a is
The axial thickness is thin so that the axial rigidity is low, and the structure has elasticity in the axial direction. On the other hand, the end ring 5 has high rigidity in the axial direction and the radial direction. The retaining ring 6 is fitted and fixed to the outer peripheral surfaces of the end rings 4a and 5.

Next, the operation of the permanent magnet type rotary electric machine configured as described above will be described. Rotating torque is generated by the rotating magnetic field generated by the stator and the field generated by the rotor 7A, and the rotor 7A rotates. At this time, the retaining ring 6
Prevents the permanent magnet 3 from scattering due to the centrifugal force acting on the permanent magnet 3 when the rotor 7A rotates, so that the rotor 7A can rotate at high speed. Then, as the rotor 7A rotates at high speed in this way,
Even if the temperature of the retaining ring 6 rises due to wind loss, eddy current loss, or the like that occurs on the outer peripheral surface of the retaining ring 6, and thermal expansion occurs in the retaining ring 6,
The end ring 5 side is rigidly fixed, but the end ring 4a having an elastic structure is elastically deformed as indicated by a chain line b, so that the thermal extension of the retaining ring 6 is absorbed. Therefore, the vibration of the rotor 7A due to the thermal expansion of the retaining ring 6 unlike the prior art does not cause a sudden change or heat bending, and the rotor 7A can be stably rotated at a high speed without being damaged or scattered. .

FIG. 2 shows a second embodiment of the present invention. In this embodiment, a part of the outer diameter side of the end ring 4b having a reduced axial thickness covers a part of the end portion of the retaining ring 6. The retaining ring 6 is fitted in the end ring 4b without any gap.

In this embodiment, similarly to the first embodiment, when the temperature of the retaining ring 6 rises and the retaining ring 6 thermally expands, the end ring 4b is elastically deformed like a chain line b. By doing so, thermal expansion of the retaining ring 6 is absorbed, and stable high speed rotation is obtained. Further, since the retaining ring 6 is further constrained in the radial direction by the tensile stress of the end ring 4b, the end ring 4b can be thinned without fear of buckling of the member. Therefore, extremely low axial rigidity can be set for the end ring 4b, and the thermal bending of the rotor 7B can be minimized.

FIG. 3 shows a third embodiment of the present invention. FIG. 3A is a sectional view of the rotor in the axial direction, and FIG. 2B is an enlarged view of a Z portion in FIG. In this embodiment,
The end ring 4c serving as a support structure having elasticity is formed in a comb shape in which a portion corresponding to each comb tooth has a small axial thickness. The end rings 4c and 5 sandwich the permanent magnet 3 in the axial direction and have a required narrow gap from the permanent magnet 3 and are shrink-fitted and fixed to the shaft 1.

In this embodiment, as in the second embodiment, when the temperature of the retaining ring 6 rises and the retaining ring 6 is thermally expanded, as shown in FIG. 3 (b), The comb teeth of the end ring 4c are elastically deformed as indicated by the chain line b, and the thermal expansion of the retaining ring 6 is absorbed, so that stable high-speed rotation is obtained. Since the end ring 4c is composed of a plurality of comb teeth each having a small axial thickness, the axial thickness of each comb tooth can be reduced without causing the buckling of the member in the radial direction. As a result, as in the second embodiment, extremely low axial rigidity can be set, and the thermal bending of the rotor 7C can be minimized.

FIG. 4 shows a fourth embodiment of the present invention. In the present embodiment, the end ring on the side that forms the elastic support structure is omitted, and the extended portion 6a on the inner diameter side is formed at the end of the retaining ring 6 to form an L-shaped cross section in the axial direction. The extension portion 6a is fitted and fixed to the shaft 1, and the extension portion 6a is thinned in the axial direction to form a structure having elasticity in the axial direction. The holding ring 6 is fixed to the shaft 1 at the end ring 5 and the extending portion 6a.

In this embodiment, since the extension portion 6a has a low axial rigidity, the thermal elongation of the retaining ring 6 extends in the direction of a with the end ring 5 side as a fixed point, and the extension portion 6a has the shape shown in FIG. It is elastically deformed and absorbed as shown by the medium chain line b. Therefore,
Similar to the first embodiment, the vibration of the rotor 7E due to the thermal expansion of the retaining ring 6 does not cause a sudden change in the vibration, heat bending, etc., and the rotor 7E is stably rotated at a high speed without being damaged or scattered. You can

FIG. 5 shows a fifth embodiment of the present invention. In the present embodiment, the end ring corresponding portion 1a is formed by cutting out from the shaft 1 a structural member corresponding to the end ring on the side having rigidity in the first to fourth embodiments. The operation and effect of the retaining ring 6 relating to the heat expansion are the same as those in the above-mentioned respective embodiments, but since the end ring equivalent portion 1a is formed by cutting out from the shaft 1, there is no need for fitting work at the same portion. Also, the number of parts is reduced. Therefore, in addition to improving the manufacturability, since the shaft 1 has an integral structure, its strength is higher than that of an end ring to be fitted later, and the probability of breakage and scattering due to centrifugal force is extremely small.

[0022]

As described above, according to the first aspect of the present invention, the retaining ring arranged on the surface of the permanent magnet is fitted and fixed to the shaft at a plurality of axial positions, and the fitting and fixing portion thereof is provided. Since the support structure having elasticity in the axial direction is provided at one position on one side in the axial direction, the thermal expansion of the retaining ring is absorbed by elastically deforming the support structure having elasticity. It is possible to prevent a sudden change in temperature, heat bending, peeling off of the permanent magnet, etc., and it is possible to perform stable high-speed rotation and improve reliability during operation.

According to the second aspect of the present invention, the fitting and fixing portion is composed of end rings arranged on both sides in the axial direction of the permanent magnet, and the elastic support structure is the shaft of one end ring. Since it is configured by reducing the thickness in the direction, it is possible to realize a supporting structure having elasticity that absorbs thermal expansion of the retaining ring with a simple structure.

According to the third aspect of the present invention, the end ring having a reduced axial thickness has a shape in which a part of the outer diameter side covers a part of the end portion of the retaining ring. The member can be made thin without fear of buckling, and the thermal elongation of the retaining ring can be effectively absorbed.

According to a fourth aspect of the present invention, the fitting and fixing portion includes end rings located on both sides of the permanent magnet in the axial direction, and the elastic support structure is in the axial direction of the end ring. The end ring can be set to have extremely low axial rigidity without the risk of buckling of the radial member, and effectively absorbs the thermal elongation of the retaining ring, because it is configured by making the cross section into a comb shape. can do.

According to the fifth aspect of the present invention, an extension portion extending toward the inner diameter side is formed at the end portion of the retaining ring to have an L-shaped cross section in the axial direction, and the extension portion is fitted to the shaft. Since the support structure having the elasticity by elastically fitting and configuring the fitting and fixing portion is configured by reducing the axial thickness of the extending portion, it is possible to absorb the thermal expansion of the retaining ring with a simple structure. You can

According to the invention of claim 6, the other end ring which does not form the elastic support structure is formed by cutting out the shaft.
The end ring that does not form a support structure is integrated with the shaft to facilitate assembly, and mechanical strength is enhanced, so that sudden vibration of rotor vibration during rotation can be prevented more accurately.

[Brief description of drawings]

FIG. 1 is an axial cross-sectional view of a rotor portion in a permanent magnet type rotary electric machine according to a first embodiment of the present invention.

FIG. 2 is an axial sectional view of a rotor section according to a second embodiment of the present invention.

FIG. 3 is an axial sectional view of a rotor portion according to a third embodiment of the present invention.

FIG. 4 is an axial sectional view of a rotor portion according to a fourth embodiment of the present invention.

FIG. 5 is an axial cross-sectional view of a rotor section according to a fifth embodiment of the present invention.

6A and 6B are an external view and a partially enlarged cross-sectional view of a rotor portion of a conventional permanent magnet type rotary electric machine.

[Explanation of symbols]

1 shaft 1a End ring equivalent 3 permanent magnet 4a-4c, 5 end ring 6 retaining ring 6a extension part 7A-7E rotor

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihiko Kazao 2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Plant (72) Inventor Yotsugu Miura Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa 2-4, Toshiba Corp. Keihin Works (56) References JP-A-64-26350 (JP, A) JP-A-3-159533 (JP, A) JP-A-5-284680 (JP, A) Kaihei 9-327141 (JP, A) JP 49-117918 (JP, A) JP 2000-17524 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 1 / 27

Claims (6)

(57) [Claims] 1. A stator formed by winding an armature winding around an armature iron core, and a plurality of permanent magnets for field magnets which are rotatably mounted on the shaft center portion of the stator and which are arranged on the peripheral surface of the shaft. In a permanent magnet type rotating electric machine having a rotor having a retaining ring arranged on the surface of these permanent magnets, the retaining ring is fitted and fixed to the shaft at a plurality of axial positions, and A permanent magnet type rotating electric machine characterized in that a portion of the fitting and fixing portion located on one side in the axial direction has a supporting structure having elasticity in the axial direction. 2. The fitting and fixing portion is composed of end rings arranged on both sides in the axial direction of the permanent magnet, and the elastic support structure is formed by reducing the axial thickness of one of the end rings. The permanent magnet type rotating electric machine according to claim 1, wherein 3. The permanent magnet according to claim 2, wherein the end ring having a reduced axial thickness has a shape such that a part of an outer diameter side thereof covers a part of an end portion of the retaining ring. Type rotating electric machine. 4. The fitting fixing portion is composed of end rings arranged on both sides of the permanent magnet in the axial direction, and the elastic support structure has a comb-shaped axial cross section of one end ring. The permanent magnet type rotating electric machine according to claim 1, wherein the permanent magnet type rotating electric machine is configured. 5. An extension portion extending to the inner diameter side is formed at an end portion of the retaining ring to have an L-shaped axial cross section, and the extension portion is fitted and fixed to the shaft to be fitted and fixed. 2. The permanent magnet type rotating electric machine according to claim 1, wherein the elastic support structure that constitutes the portion and is configured by reducing the axial thickness of the extending portion. 6. The end ring, which does not form the elastic support structure, is formed by cutting out the shaft.
The permanent magnet type rotating electrical machine according to any one of 1.