JP2010057233A - Rotor structure of permanent magnet rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor structure of a permanent magnet rotating electric machine, which is enhanced in the transmission property of rotation torque, can suppress the occurrence of eddy current loss, and is high in productivity by means of a practical production method, while the permanent magnet serves as the interference of a reinforcing ring to endure high speed rotation. <P>SOLUTION: In the rotor structure of the permanent magnet rotating electric machine, cylindrically formed permanent magnets 3 are disposed on the outer circumference of a rotor shaft 2 to transmit the torque working on the permanent magnets 3 to the rotary shaft 2. The rotor structure includes a cylindrical reinforcing ring 5 provided on the outer circumference of the permanent magnets 3 so as to project both ends of the permanent magnets 3, and a side surface member 4 formed into a bottomed cylindrical shape and having a portion projecting from the reinforcing ring 5 of the permanent magnet 3 being fit into the cylindrical portion 4a and also having the rotary shaft 2 being fit into the shaft hole 4c formed at the bottom 4b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotor structure of a permanent magnet rotating machine applicable to ultra-high speed rotation, and in particular, a cylindrical permanent magnet is arranged on the outer peripheral portion of a rotating shaft so that rotational torque acting on the permanent magnet is transmitted to the rotating shaft. The present invention relates to a rotor structure of a permanent magnet type rotating machine.

  Conventionally, as a rotor structure of a permanent magnet type synchronous motor applicable to ultra-high speed rotation or a permanent magnet type rotary machine such as a permanent magnet type synchronous generator, a cylindrical permanent magnet is also made of a cylindrical non-magnetic high strength. A rotor structure that is press-fitted or shrink-fitted or cold-fitted with a material (hereinafter referred to as a reinforcing ring) and a rotor structure that is wound with a nonmagnetic metal wire are well known (for example, see Patent Documents 1 and 2).

  In such a rotor structure using a ring magnet, it is fastened to the reinforcing ring or the like to prevent the permanent magnet from being damaged due to a tensile stress exceeding the allowable tensile stress of the permanent magnet acting on the inner diameter side of the permanent magnet during high-speed rotation. A fee is provided. Furthermore, the rotational torque acting on the permanent magnet is transmitted to the rotating shaft by taking up a tightening margin so that the shaft and the permanent magnet are not separated by centrifugal force at high speed rotation or by adhering the rotating shaft and the permanent magnet. . Some of the reinforcing rings use high-strength fibers such as carbon fibers or nonmagnetic metal wires to reduce eddy current loss.

  On the other hand, there is also a rotor structure in which a cylindrical permanent magnet is press-fitted, shrink-fitted, or cold-fitted with a reinforcing ring (see, for example, Patent Document 3).

  In such a rotor structure using a columnar permanent magnet, damage to the permanent magnet is prevented by taking a tightening margin so that a tensile stress exceeding the allowable tensile strength of the permanent magnet does not work during high-speed rotation. . The reinforcing ring and the shaft are press-fitted or cold-fitted or welded at both ends of the permanent magnet. Then, the rotational torque acting on the permanent magnet is transmitted to the shaft by tightening so that the reinforcing ring and the permanent magnet and the shaft and the permanent magnet are not separated by the centrifugal force during high-speed rotation. Since the permanent magnet has a columnar shape, it has an advantage that it is more resistant to centrifugal force than the cylindrical magnet having the same outer diameter and length, and the magnetomotive force of the magnet can be increased.

Japanese Patent Laid-Open No. 03-159533 JP 2005-312250 A JP 2002-354724 A

  However, in the rotor structure as described in Patent Documents 1 and 2 mentioned above, the rotor structure is rotated in order to prevent a tensile stress exceeding the allowable tensile stress of the permanent magnet from acting, or depending on centrifugal force or operating temperature conditions. In order to prevent the shaft and the permanent magnet from separating, it is necessary to make a large allowance, and it is necessary to raise the press-fit or shrink-fit temperature to a temperature that is practically difficult, in other words, unsuitable for mass production. There was a problem that there was. In order to increase the tightening allowance, it is necessary to make the temperature practically difficult even in the case of cold fitting, and there is a concern that the improvement of productivity may be hindered.

  In the rotor structure in which the rotational torque of the permanent magnet is transmitted to the shaft by bonding the shaft and the permanent magnet, the function of the adhesive may be reduced in a high temperature environment (100 ° C. or higher). Once the permanent magnet is peeled off from the rotating shaft due to a decrease in the function of the adhesive, the bonded state will not be restored.Therefore, in the high temperature environment, the rotating shaft and the permanent magnet may be separated so that torque cannot be transmitted to the shaft. there were.

  In addition, when high-strength fibers are used as the reinforcing ring, since the high-strength fibers have a small coefficient of thermal expansion, it is difficult to shrink-fit, and thus press-fit or permanent magnets are cold-fitted. However, since the thermal expansion coefficient of permanent magnets is about half that of iron, it is difficult to make a large tightening allowance, preventing the application of tensile stress exceeding the allowable tensile stress of permanent magnets, centrifugal force and use It was difficult to prevent the shaft and the permanent magnet from separating regardless of the temperature conditions.

  Further, in the rotor structure as described in Patent Document 3, if the tightening margin is set so that the tensile stress exceeding the allowable tensile stress of the permanent magnet does not work, the tightening margin becomes large, and press fitting or firing is performed. It may be necessary to raise the fitting temperature to a practically difficult temperature, in other words, a temperature unsuitable for mass production, and there is a possibility that improvement in productivity may be suppressed. This was the same even when the cold fitting was performed.

  Further, when a cylindrical permanent magnet is used, the rotating shaft is divided with the permanent magnet interposed therebetween. As a method of fixing the rotating shaft to both ends of the permanent magnet, there are a method in which the rotating shaft is press-fit, shrink-fitted, or cold-fitted with a reinforcing ring, or the rotating shaft and the reinforcing ring are fixed by welding. Care was required for the rigidity and the work was complicated.

  When the rotary shaft is press-fit, shrink-fitted, or cold-fitted with a reinforcing ring, the rotational torque acting on the permanent magnet is transmitted to the reinforcing ring and further transmitted to the rotating shaft. If the allowance is taken so that the ring and the rotating shaft, and the reinforcing ring and the permanent magnet are not separated from each other, the allowance becomes large, and the press-fit or shrink-fit temperature is a temperature that is practically difficult, in other words, a temperature unsuitable for mass production It may be necessary to raise it to a maximum. This is the same even when performing cold fitting, and there is a possibility that improvement in productivity may be hindered.

  In addition, in the Japanese Patent Application No. 2007-240451, the present applicant arranges a cylindrical permanent magnet on the outer peripheral portion of the rotating shaft as a rotor structure that solves the above-described problem, and rotates both ends of the permanent magnet. An annular side plate made of a metal member into which the shaft can be integrally moved is provided, and the permanent magnet and the side plate are tightened so as to be integrally movable by a cylindrical reinforcing ring made of a metal material. It has been proposed to transmit the rotational torque acting on the magnet to the rotating shaft.

  However, in the structure of the above-mentioned Japanese Patent Application No. 2007-240451, a permanent magnet that works with torque and a side plate that does not work with torque are tightened so as to be able to move together. Therefore, a twisting direction force acts on the reinforcing ring when the rotating machine is driven, and eddy current loss may occur, which may affect the efficiency of the rotating machine.

  For this reason, the present invention is highly productive by a practical manufacturing method, is excellent in rotational torque transmission, and generates eddy current loss, although the permanent magnet is capable of withstanding the high-speed rotation of the permanent magnet. An object of the present invention is to provide a rotor structure of a permanent magnet type rotating machine capable of suppressing the above.

  In the rotor structure of the permanent magnet type rotating machine according to the first invention for solving the above-mentioned problems, a permanent magnet formed in a cylindrical shape is arranged on the outer peripheral portion of the rotating shaft, and the torque acting on the permanent magnet is provided. In the rotor structure of the permanent magnet type rotating machine configured to transmit to the rotating shaft, a cylindrical reinforcing member provided on an outer peripheral portion of the permanent magnet so that both ends of the permanent magnet protrude, and a bottomed cylinder The portion of the permanent magnet that protrudes from the reinforcing member is inserted into the cylindrical portion, while the rotating shaft is inserted into the shaft hole formed in the bottom portion, and moves integrally with the permanent magnet and the rotating shaft. And a side member configured to be possible.

  In the rotor structure of the permanent magnet type rotating machine according to the second invention, in the first invention, the side member has a small diameter portion and a large diameter portion in the cylindrical portion, and the small diameter portion is formed of the permanent magnet. While inserting the part which protruded from the said reinforcement member, the said large diameter part coat | covers the edge part of the said reinforcement member, It is characterized by the above-mentioned.

  A rotor structure of a permanent magnet type rotating machine according to a third invention is characterized in that, in the first or second invention, the reinforcing member is made of glass fiber reinforced plastic or carbon fiber reinforced plastic.

  According to the rotor structure of the first permanent magnet type rotating machine of the present invention described above, the permanent magnet formed in a cylindrical shape is arranged on the outer peripheral portion of the rotating shaft, and torque acting on the permanent magnet is transmitted to the rotating shaft. In the rotor structure of the permanent magnet type rotating machine, the cylindrical reinforcing member provided on the outer peripheral portion of the permanent magnet so that both ends of the permanent magnet protrude, and the bottomed cylindrical shape are formed on the cylindrical portion. While inserting the part which protruded from the reinforcement member of the permanent magnet, the rotating shaft was inserted in the shaft hole formed in the bottom part, and it was provided with the side member comprised so that the permanent magnet and the rotating shaft could move integrally. Therefore, the inner peripheral surface of the reinforcing member is in contact with only the permanent magnet, and no force is applied to the reinforcing member in the twisting direction. When a metal member is used as the reinforcing member, eddy current loss can be suppressed. Can be twisted as a reinforcing member It is also possible to prevent damage due to twisting forces as resistance to force is a relatively low high-strength fibers.

  Furthermore, since an undivided cylindrical permanent magnet is used, the outer diameter is polished after the permanent magnet is fixed to the rotating shaft as compared with the case where the cylindrical permanent magnet is divided in the circumferential direction or the axial direction. No process is required, productivity can be greatly improved, and cost can be reduced.

  Further, since the permanent magnet is not divided in the circumferential direction, stress concentration does not occur in the reinforcing member, and when the reinforcing member is composed of high-strength fibers, the high tensile strength characteristics of the high-strength fibers are effectively used. be able to. Therefore, compared with the case where the permanent magnet is divided in the circumferential direction, the thickness of the reinforcing member can be reduced, and the electrical gap between the stator and the rotor (the distance between the magnet and the stator) is reduced. The characteristics of the rotating machine can be improved.

  Since the inner diameter of the permanent magnet does not need to be in contact with the rotating shaft, the tightening margin between the reinforcing member and the permanent magnet may be such that the permanent magnet is not damaged by centrifugal force. Further, it is not necessary to fix the permanent magnet to the rotating shaft with an adhesive or the like, and it can be used stably even in a high temperature environment.

  Therefore, although the permanent magnet is capable of withstanding high-speed rotation, it is highly productive by a practical manufacturing method, and the rotational torque acting on the permanent magnet can be reliably transmitted to the rotating shaft, and the eddy current Generation of loss can be suppressed.

  According to the rotor structure of the permanent magnet type rotating machine according to the second invention, the side member has a small diameter portion and a large diameter portion in the cylindrical portion, and the small diameter portion projects from the reinforcing member of the permanent magnet. On the other hand, since the large diameter portion covers the end portion of the reinforcing member, the contact portion between the end surface of the permanent magnet and the side member can be covered with the large diameter portion, and scattering of the magnet powder can be suppressed. . If the outer periphery of the reinforcing member can be press-fitted or shrink-fitted with a side member, the effect is highest.

  According to the rotor structure of the permanent magnet type rotating machine according to the third invention, the reinforcing member is made of glass fiber reinforced plastic (hereinafter referred to as GFRP) or carbon fiber reinforced plastic (hereinafter referred to as CFRP). Without causing it, it is possible to further reduce the eddy current loss when the rotating machine is driven as compared with the case where a nonmagnetic metal is used for the reinforcing member.

The thermal expansion coefficient of the permanent magnet is 6.5 × 10 ⁻⁶ / K, which is about half of the thermal expansion coefficient of iron. When a material having a higher thermal expansion coefficient than the permanent magnet is used for the reinforcing member, Since the tightening allowance between the permanent magnet and the reinforcing member is reduced below, it may be necessary to increase the tightening allowance in advance. On the other hand, since the thermal expansion coefficient of GFRP or CFRP is almost 0, the use of the GFRP or CFRP as the material for the reinforcing member increases the tightening allowance in a high temperature environment, and a metal material is used as the reinforcing member. In comparison, it is possible to reduce the tightening allowance.

  Embodiments for carrying out the present invention will be described in detail in the following examples.

  A first embodiment of the present invention will be described with reference to FIGS. 1A is a partial cross-sectional view of a rotor structure of a high-speed permanent magnet type rotating machine according to the present embodiment, FIG. 1B is a view taken along the line AA in FIG. 1A, and FIG. It is sectional drawing of the side member which concerns on an example. The rotor structure of the high-speed permanent magnet type rotating machine according to the present embodiment is applied to, for example, an ultra-high speed rotating permanent magnet type synchronous motor or a rotor of a permanent magnet type synchronous generator.

  As shown in FIG. 1, the rotor 1 includes a rotating shaft 2, a permanent magnet 3 that is formed in an undivided complete cylindrical shape and disposed on the outer peripheral portion of the rotating shaft 2, and both end surfaces 3 a of the permanent magnet 3. And a reinforcing ring 5 as a reinforcing member formed in a cylindrical shape and disposed on the outer peripheral portion of the permanent magnet 3.

  The reinforcing ring 5 is a cylindrical member made of GFRP or CFRP. The outer periphery of the permanent magnet 3 is tightened by press-fitting, and the permanent magnet 3 is permanently attached to the permanent magnet 3 by centrifugal force acting on the permanent magnet 3 when the rotating machine is driven. The permanent magnet 3 is prevented from being damaged by a tensile stress exceeding the allowable tensile stress of the magnet 3.

  In this embodiment, the length of the reinforcing ring 5 in the axial direction is shorter than the length of the permanent magnet 3 in the axial direction by a predetermined length, and both ends of the permanent magnet 3 are approximately equal in length from the reinforcing ring 5. It is in a protruding state. The inner diameter of the reinforcing ring 5 is set such that the tightening margin for the permanent magnet 3 is such that the tensile stress acting on the permanent magnet 3 as the rotating machine is driven does not exceed the allowable tensile stress.

  Further, the side member 4 is formed of a non-magnetic metal material in a cup shape, in other words, a bottomed cylindrical shape, and as shown in FIG. 2, the cylindrical portion 4a and one open end of the cylindrical portion 4a are closed. And a bottom portion 4b. The length of the cylindrical portion 4 a in the axial direction is substantially the same as that of the portion protruding from the reinforcing ring 5 of the permanent magnet 3. Further, the bottom 4b has a shaft hole 4c at its axial center.

  Such a side member 4 tightens the outer peripheral surface of the portion protruding from the reinforcing ring 5 of the permanent magnet 3 by the cylindrical portion 4a, while fixing the rotating shaft 2 to the shaft hole 4c by press-fitting or shrink-fitting. 3 and the rotary shaft 2 are connected so as to be able to move integrally, so that torque acting on the permanent magnet 3 can be transmitted to the rotary shaft 2.

  The permanent magnet 3 is fitted into the rotary shaft 2 with a gap, so that a gap 6 with a minute distance d is formed between the rotary shaft 2 and the permanent magnet 3. That is, in this embodiment, the permanent magnet 3 is set to be non-contact with the rotating shaft 2.

  Thus, the rotor 1 of this embodiment transmits the torque acting on the permanent magnet 3 to the side member 4 by fitting the end portion of the permanent magnet 3 and the side member 4, and this is transmitted to the shaft hole 4 of the side member 4. The rotary shaft 2 is press-fitted or shrink-fitted into the rotary shaft 2.

  According to the rotor structure of the permanent magnet type rotating machine according to the present embodiment, as described above, the permanent magnet 3 has an undivided complete cylindrical shape, and the cylindrical permanent magnet 3 is divided in the circumferential direction or the axial direction. Compared with the case where the permanent magnet 3 is fixed to the rotating shaft 2, a process such as polishing the outer diameter is not necessary, so that the productivity is greatly improved and the cost is low.

  Further, since there is no need to make the inner diameter of the permanent magnet 3 contact the rotary shaft 2, the tightening allowance between the reinforcing ring 5 and the permanent magnet 3 may be such that the permanent magnet 3 is not damaged by centrifugal force. Moreover, since it is not necessary to fix the rotating shaft 2 and the permanent magnet 3 with an adhesive etc., it can be used stably also in a high temperature environment.

  Furthermore, since the permanent magnet 3 is not divided in the circumferential direction, stress concentration does not occur in the reinforcing ring 5, and the high tensile strength characteristics of GFRP or CFRP constituting the reinforcing ring 5 can be used effectively. Therefore, the thickness of the reinforcing ring 5 can be reduced as compared with the case where the permanent magnet 3 is divided in the circumferential direction, and the electrical gap between the stator (not shown) and the rotor 1 (with the permanent magnet 3 and The distance between the stators) can be reduced, and the characteristics of the rotating machine are improved.

  In addition, since the inner peripheral surface of the reinforcing ring 5 is in contact with only the permanent magnet 3, no force in the twisting direction acts on the reinforcing ring 5, and the rotating shaft 2 and the permanent magnet 3 are not in contact with each other. However, GFRP or CFRP can be used as the reinforcing ring 5 while being able to reliably transmit the rotational torque acting on the permanent magnet 3 to the rotating shaft 2. Therefore, no eddy current is generated, and eddy current loss during driving of the rotating machine can be reduced.

  In the present embodiment, an example in which GFRP or CFRP is used as the reinforcing ring 5 is shown, but a nonmagnetic metal may be used as the reinforcing ring 5. As described above, in this embodiment, since the inner peripheral surface of the reinforcing ring is configured to contact only the permanent magnet 3, even if a nonmagnetic metal is used as the reinforcing ring 5, the reinforcing ring 5 is twisted. Force is not generated and eddy current loss can be suppressed.

  A second embodiment of the present invention will be described in detail with reference to FIGS. FIG. 3 is a partial sectional view showing a rotor structure of the permanent magnet type rotating machine according to the present embodiment, and FIG. 4 is a sectional view of a side member according to the present embodiment. In this embodiment, the side member 14 shown in FIG. 3 is used in place of the side member 4 shown in FIG. Other configurations are substantially the same as those shown in FIG. 1 and described above. Hereinafter, the same members are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIGS. 3 and 4, in this embodiment, the side member 14 is formed by forming a nonmagnetic metal material into a bottomed cylindrical shape. As shown in FIG. 4, the cylindrical portion 14a and the cylindrical portion 14a And a bottom portion 14b that closes one open end. The cylindrical portion 14 a is set so that its axial length is longer than the portion protruding from the reinforcing ring 5 of the permanent magnet 3. The bottom portion 14b has a shaft hole 14c in the axial center portion.

  Further, the cylindrical portion 14a is formed so that its outer diameter is constant, while its inner diameter changes stepwise. Specifically, a small diameter portion 14d is formed on the inner peripheral surface of the cylindrical portion 14a on the shaft hole 14c side, and a large diameter portion 14e having a larger inner diameter than the small diameter portion 14d is formed on the opening end side. Specifically, the inner diameter of the small-diameter portion 14d has an allowance relative to the outer periphery of the permanent magnet 3, and the inner diameter of the large-diameter portion 14e is about the outer diameter of the reinforcing ring 5 (preferably relative to the outer periphery of the reinforcing ring 5). To the extent that they have a tightening allowance).

  Such a side member 4 tightens the outer peripheral surface of the portion protruding from the reinforcing ring 5 of the permanent magnet 3 by the small diameter portion 14d by press fitting or shrink fitting, while fixing the rotating shaft 2 to the shaft hole 14c, In addition to being configured to transmit the rotational torque acting on the permanent magnet 3 to the rotary shaft 2, the end of the reinforcing ring 5 is covered with the large-diameter portion 14e, so that the permanent magnet 3 is against the stator side. To prevent exposure.

  According to the rotor structure of the permanent magnet type rotating machine according to the present embodiment described above, in addition to the effects of the first embodiment, there is a minute gap between the reinforcing ring 5 and the side member 14 due to the centrifugal force due to the high speed rotation. Even if it occurs, the powder of the permanent magnet 3 does not leak from there, and the powder of the permanent magnet 3 does not scatter to a rotating machine or a device other than the rotating machine. Thereby, the soundness of apparatuses other than rotating machines, such as a rotating machine and peripheral equipment, can be improved more. If the outer periphery of the reinforcing ring 5 can be press-fitted or shrink-fitted by the large diameter portion 14e, a higher effect can be obtained.

  INDUSTRIAL APPLICABILITY The present invention can be used for a rotor structure of a permanent magnet type rotating machine applicable to ultra-high speed rotation, and in particular, a cylindrical permanent magnet is arranged on the outer peripheral portion of a rotating shaft to rotate rotational torque acting on the permanent magnet. The present invention is suitable for application to a permanent magnet type rotary electric rotor structure adapted to transmit to a shaft.

FIG. 1A is a partial cross-sectional view of a rotor structure of a permanent magnet type rotating machine according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG. It is sectional drawing of the side member in Example 1 of this invention. It is a fragmentary sectional view of the rotor structure of the permanent magnet type rotating machine concerning the 2nd example of the present invention. It is sectional drawing of the side member in Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Rotating shaft 3 Permanent magnet 4,14 Side member 4a, 14a Cylindrical part 4b, 14b Bottom part 4c, 14c Shaft hole 5 Reinforcement ring 6 Gap 14d Small diameter part 14e Large diameter part

Claims (3)

In the rotor structure of the permanent magnet type rotating machine, a permanent magnet formed in a cylindrical shape is arranged on the outer periphery of the rotating shaft, and the torque acting on the permanent magnet is transmitted to the rotating shaft.
A cylindrical reinforcing member provided on the outer periphery of the permanent magnet so that both ends of the permanent magnet protrude;
It is formed in a cylindrical shape with a bottom, and a portion protruding from the reinforcing member of the permanent magnet is fitted into the cylindrical portion, while the rotating shaft is fitted into a shaft hole formed in the bottom, and the permanent magnet and the rotation A rotor structure for a permanent magnet type rotating machine, comprising: a shaft and a side member configured to be integrally movable.   The side member has a small-diameter portion and a large-diameter portion in the cylindrical portion, and the small-diameter portion is inserted into a portion protruding from the reinforcing member of the permanent magnet, while the large-diameter portion is an end portion of the reinforcing member. The rotor structure of the permanent magnet type rotating machine according to claim 1, wherein: The rotor structure of a permanent magnet type rotating machine according to claim 1 or 2, wherein the reinforcing member is made of glass fiber reinforced plastic or carbon fiber reinforced plastic.

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