JP2010200573A - Permanent magnet type synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type synchronous motor, capable of lessening stress to act on a stator core, without changing the shape of the stator core. <P>SOLUTION: The permanent magnet type synchronous motor 1 includes the stator core 2 formed of a laminated steel plate; a rotor core 3 having a permanent magnet 25 rotatably arranged in the stator core 2; and a cylindrical frame 4 supporting the outer peripheral surface of the stator core 2. A stress relief section 31, which is in no-contact with the stator core 2, is formed circumferentially at predetermined intervals on the inner peripheral surface facing the stator core 2 of the frame 4. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention includes a stator core formed of laminated steel sheets, a frame that supports an outer peripheral surface of the stator core, and a rotor core having a permanent magnet that is rotatably disposed in the stator core. The present invention relates to a permanent magnet type synchronous motor.

In recent years, permanent magnet type synchronous motors using permanent magnets have been attracting attention and their application has been increasing in place of conventionally used induction motors in order to increase the efficiency of motors.
Paying attention to such permanent magnet type synchronous motor loss, copper loss generated in winding coil, permanent magnet loss, rotor core and stator core loss (hereinafter referred to as core loss), bearing friction loss and stray Can be classified as load loss.

Here, it is known that the magnetic steel sheet used for the stator core increases iron loss, that is, core loss, by applying compressive stress to the laminated steel sheet (see, for example, Non-Patent Document 1).
That is, when the frame is shrink-fitted to the stator core, a compressive stress is applied to the stator core, and the core loss is increased from the catalog value.

For this reason, conventionally, in order to reduce the stress acting on the stator core in order to suppress the increase in core loss, it is described that the outer peripheral surface of the stator core is provided with a portion in contact with the frame and a non-contact portion. (For example, see Patent Documents 1 and 2).
Here, in the conventional example described in Patent Document 1, a fixed iron core is formed between a plurality of slots arranged in a week direction and adjacent slots, and a magnetic teeth on which a coil is wound, and a magnetic teeth. A plurality of regions divided in the circumferential direction by a radial center line of the plurality of regions, and a contact region in contact with the inner peripheral surface of the sealed container arranged at a predetermined interval in the circumferential direction in a predetermined number of regions among the plurality of regions; A stator with a non-contact area formed between the contact areas is described.

JP 2008-193778 A JP 2008-271616 A

“Measurement of Magnetic Properties of Laminated Electrical Steel Sheets under Compressive Stress” Proceedings of the Annual Conference of the 2008 IEEJ

  However, in the conventional examples described in Patent Documents 1 and 2, since a contact portion and a non-contact portion that contact the inner peripheral surface of the hermetic container are formed on the stator core, a new product However, there is no problem because a new mold for punching electromagnetic steel sheets is manufactured, but when applied to a commercial permanent magnet type synchronous motor, the mold for punching electromagnetic steel sheets must be changed. I must. Thus, when changing a metal mold | die, the production cost of a new metal mold | die will generate | occur | produce, and also there exists an unsolved subject that a long period is required until equipment replacement.

  Therefore, the present invention has been made by paying attention to the unsolved problems of the above-described conventional example, and can reduce the stress acting on the stator core without changing the shape of the stator core. The object is to provide a synchronous motor.

  In order to achieve the above object, a permanent magnet type synchronous motor according to claim 1 includes a stator core formed of laminated steel sheets, a cylindrical frame that supports an outer peripheral surface of the stator core, and an inside of the fixed core. A permanent magnet type synchronous motor including a rotor core having a permanent magnet rotatably disposed on the inner peripheral surface of the frame facing the stator core, the stator core being in a non-contact state The stress relaxation portion is formed at a predetermined interval in the circumferential direction.

According to this configuration, since the stress relaxation portion that is in a non-contact state with the stator core is formed on the inner peripheral surface facing the outer peripheral surface of the stator core on the frame side, the stress relaxation portion gives the stator core. Stress can be relaxed.
Further, the permanent magnet type synchronous motor according to claim 2 is characterized in that the stress relieving part is constituted by a concave part.

According to this configuration, by forming the stress relaxation portion with the concave portion, the bending stress of the frame at the concave portion position can be reduced, and the compressive stress acting on the stator core can be reduced in the entire frame.
The permanent magnet synchronous motor according to claim 3 is characterized in that the number of slots of the stator core and the number of stress relieving portions are set to the same number.

According to this configuration, since the number of slots of the stator core and the number of stress relaxation portions are set to the same number, the stress acting on the stator core can be made uniform.
According to a fourth aspect of the present invention, there is provided the permanent magnet type synchronous motor according to the third aspect of the invention, wherein the stator core is formed by connecting the divided cores constituting the slots in a circumferential direction in an annular shape. It is characterized by being.

According to this configuration, since the number of divided cores and the number of stress relaxation portions are the same, the stress acting on each divided core can be made uniform and relaxed.
The permanent magnet synchronous motor according to claim 5 is characterized in that the stress relaxation portion is filled with a synthetic resin material having thermal conductivity.
According to this configuration, by filling the stress relaxation part that is not in contact with the stator core with a synthetic resin material having thermal conductivity, the heat generated in the stator core is also conducted to the frame in the stress relaxation part to dissipate heat. The effect can be improved.

According to a sixth aspect of the present invention, there is provided a permanent magnet type synchronous motor, wherein the stator core is provided with a stress relaxation portion on the outer peripheral surface thereof so as not to be in contact with the inner peripheral surface of the frame.
According to this configuration, since the stress relaxation portion is also formed in the stator core, the stress relaxation effect can be further improved.

  According to the present invention, since the stress relaxation portions are formed at equal intervals on the inner peripheral surface of the frame that supports the outer peripheral surface of the stator core, the compressive stress applied to the stator core can be relaxed by the stress relaxation portions. Thus, the effect of reducing the core loss of the stator core and providing a highly efficient permanent magnet type synchronous motor can be obtained.

It is sectional drawing which shows the 1st Embodiment of this invention. It is sectional drawing which shows the 2nd Embodiment of this invention. It is sectional drawing which shows the 3rd Embodiment of this invention. It is sectional drawing which shows the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a first embodiment of the present invention, in which 1 is a permanent magnet type synchronous motor. The permanent magnet synchronous motor 1 includes a stator core 2, a rotor core 3 that is rotatably disposed on an inner peripheral surface side of the stator core 2 via a predetermined gap, and a stator core 2. It is comprised with the cylindrical frame 4 which supports an outer peripheral surface.

The stator core 2 has a configuration in which, for example, 12 T-shaped split cores 11 on which high-permeability electromagnetic steel plates are stacked are connected in an annular shape.
Each of the divided cores 11 has a stator yoke 12 whose outer peripheral surface is formed in an arc shape having the same curvature as the frame 4 and extends in the circumferential direction, and a circumferential center on the inner peripheral surface of the stator yoke 12. The portion is formed in a T shape with a tooth portion 13 extending inward, that is, in a normal direction toward the central axis. A hat portion 14 is formed at the tip of the tooth portion 13. A slot 15 is formed between the teeth 13 of the adjacent split cores 11. An excitation coil 16 wound around the tooth portion 13 is wound in the slot 15. The shape of the hat portion 14 is set so as to form a relatively narrow slot opening 17 between the divided cores 11 adjacent to each other.

  As with the stator core 3, the rotor core 3 has four magnetic poles 22 formed by laminating a rotor core plate 21 formed by punching a high-permeability electromagnetic steel plate. The rotor core 3 includes a plurality of, for example, four slots 24 formed so as to penetrate in the axial direction, and permanent magnets 25 inserted in the slots 24 so that the magnetic poles 22 adjacent in the circumferential direction have different polarities. It has. Here, the permanent magnet 25 is composed of a rare earth magnet. A rotating shaft 26 is inserted into the center position of the rotating core 3.

  Further, the cylindrical frame 4 is formed with twelve recesses 31 as stress relieving portions equal to the number 12 of the slots 15 of the stator core 2 at a predetermined interval on the inner peripheral surface thereof, for example, by cutting. Yes. A stator core 2 in which the divided cores 11 are connected in an annular shape is fixed to the inner peripheral surface of the cylindrical frame 4 by shrink fitting.

Next, the operation of the above embodiment will be described.
Since the permanent magnet type synchronous motor 1 has a configuration of a permanent magnet type synchronous motor of an embedded magnet type, the central portion in the circumferential direction between the permanent magnets 25 in the magnetic pole 22 of the rotor core 3 and the axis of the rotary shaft 26 A line connecting the two becomes the d-axis. In addition, a line connecting between the permanent magnets 25 of different magnetic poles between the adjacent magnetic poles 22 of the rotor core 3 and the axis of the rotary shaft 26 is the q axis. For this reason, the permanent magnet 25 having the same magnetic resistance as the air gap G is present in the magnetic path of the magnetic flux in the d-axis direction, and the magnetic flux is difficult to pass, but the magnetic flux in the q-axis direction can pass through the rotor core 3. Therefore, the magnetic resistance in this direction is reduced, and the d-axis inductance Ld and the q-axis inductance Lq have saliency Ld <Lq. For this reason, the self-inductance and mutual inductance of the armature winding change at twice the rotation angle, and the armature linkage magnetic flux of the permanent magnet also changes at the cosine of the rotation angle of the rotor 4.

  Therefore, the torque can be increased by adding the reluctance torque to the magnet torque. Here, the magnet torque is a torque generated by energy conversion due to a change in only the armature linkage magnetic flux of the permanent magnet. The reluctance torque is a torque generated by converting magnetic energy stored in the air gap G into mechanical energy in accordance with changes in the armature self and mutual inductance.

  The frame 4 and the split core 11 are fixed to the stator core 2 connected in an annular shape by shrink fitting. At this time, compressive stress is applied to the stator core 2 by the frame 4. However, the same number of recesses 31 as the number of slots of the stator core 2, that is, the number of the split cores 11, are formed on the inner peripheral surface of the frame 4. For this reason, the outer peripheral surface of the stator core 2 and the inner peripheral surface of the frame 4 are not in contact with each other at the position of the recess 31, and compressive stress does not act on the stator core 2 in this portion. For this reason, the contact area between the frame 4 and the stator core 2 is reduced, and the compressive stress applied to the stator core 2 by the frame 4 can be relaxed. For this reason, when the compressive stress which the stator core 2 receives decreases, the increase in the core loss by a compressive stress can be suppressed.

In addition, since the number of recesses 31 serving as stress relaxation portions is set to be the same as the number of slots of the stator core 2, that is, the same as the number of the split cores 11, the compressive stress applied to each split core 11 can be made uniform. It is possible to prevent the compressive stress from becoming unbalanced.
Furthermore, since the recessed part 31 used as a stress relaxation part was provided in the junction part of the split cores 11, a compressive stress does not act on this junction part, and it prevents that a position shift arises in the junction part of the split core 11. FIG. be able to.

  In addition, since the concave portion 31 serving as the stress relaxation portion is formed on the inner peripheral surface of the frame 4, the compression stress can be relaxed without changing the shape of the stator core 2, so that the permanent magnet synchronous motor 1 Is commercially available, it is not necessary to remanufacture a mold for punching out the stator core 2, and it is only necessary to form the recess 31 in the frame 4, thereby reducing the cost of mold production and increasing the core loss. A permanent magnet type synchronous motor that suppresses the increase can be manufactured. Moreover, the recessed part 31 used as the stress relaxation part formed in the flame | frame 4 can be easily formed by cutting, and can suppress a manufacturing cost increase.

Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, except that the concave portion 31 as the stress relaxation portion is formed in the central portion in the circumferential direction of the stator yoke 12 of the split core 11 constituting the stator core 2. 1 has the same configuration as that of the first embodiment described above, and the same reference numerals are given to corresponding parts to those in FIG. 1, and the detailed description thereof will be omitted.

  Also according to the second embodiment, since the concave portion 31 serving as the stress relaxation portion is formed in the frame 4, the same effect as the first embodiment described above can be obtained, and the concave portion 31 is formed on the split core 11. Since the stator yoke 12 is formed at a position opposed to the central portion in the circumferential direction, the compressive stress applied to the central portion of the stator yoke 12 can be relieved, and the effect of relieving the compressive stress on the split core 11 is biased. It can be demonstrated reliably without any problems. In the first embodiment, since the recess 31 is formed at the joint between the split cores 11, when the center position in the circumferential direction of the recess 31 is shifted from the joint at the time of assembly, the split core 11. However, in this second embodiment, the concave portions 31 face each other for each stator yoke 12 of the split core 11, and the split cores are separated from each other. 11 can exhibit an accurate stress relaxation effect.

  In the second embodiment, the case where the concave portion 31 is opposed to the central portion in the circumferential direction of the stator yoke 12 of the split core 11 has been described. However, the present invention is not limited to this. The concave portion 31 may be opposed to a position deviated from the central portion of the eleventh stator yoke 12 in the circumferential direction.

Next, a third embodiment of the present invention will be described with reference to FIG.
This third embodiment is the same as that of the first embodiment described above except that a heat conductive member 32 such as a synthetic resin material having thermal conductivity is filled in the recess 31 serving as a stress relaxation portion. The components corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the third embodiment, since the heat conductive member 32 such as a synthetic resin material having thermal conductivity is filled in the concave portion 31 serving as the stress relaxation portion, the frame is provided by providing the concave portion 31 serving as the stress relaxation portion. 4, the contact area between the stator core 2 and the heat dissipation effect is reduced by this amount. However, by filling the recess 31 with the heat conducting member 32, the stator core 2 can be formed in the recess 31. The heat generated by the core loss can be conducted to the frame 4 through the heat conducting member 32, and the heat dissipation effect can be further improved.

  Incidentally, when the concave portion 31 does not exist between the stator core and the frame, the stator core 2 generates heat due to the temperature rise due to the core loss, but normally the heat generation is radiated into the air through the frame. Is done. However, when there is a recess 31 between the stator core and the frame and air exists in the recess, the thermal resistance increases due to the reduction of the contact area, and the entire circumference of the stator core 2 contacts the frame. Compared with the case where it is doing, the heat dissipation characteristic will deteriorate. However, by filling the recess 31 with the heat conducting member as in the third embodiment, heat conduction in the recess 31 can be performed, and the heat dissipation effect can be further improved.

In the third embodiment, the case where the recess 31 of the first embodiment is filled with the heat conducting member 32 has been described. However, the present invention is not limited to this, and the second embodiment is not limited thereto. The recess 31 may be filled with a heat conductive member.
Moreover, in the said 1st-3rd embodiment, although the case where the recessed part 31 was applied as a stress relaxation part was demonstrated, it is not limited to this, Arbitrary arbitrary shapes, such as a cross-sectional semicircle shape and cross-sectional trapezoid shape, etc. A groove portion having a cross-sectional shape can also be applied. In short, it is sufficient that the outer peripheral surface of the stator core 2 is brought into a non-contact state.

Moreover, in the said 1st-3rd embodiment, although the case where the recessed part 31 was formed only in the flame | frame 4 was demonstrated, as shown in FIG. 4, the split core 11 of the stator core 2 also has a stress relaxation part. You may make it form the recessed part 33 which becomes. In this case, the stress relaxation effect of the fixed core 2 can be further exhibited.
Moreover, in the said 1st-3rd embodiment, although the case where the stator core 2 was comprised with the division | segmentation core 11 was demonstrated, it is not limited to this, A stator yoke is formed in an annular | circular shape. The integrated stator core may be applied.

In the first to third embodiments, the case where the present invention is applied to an interior permanent magnet (IPM) permanent magnet synchronous motor has been described, but the present invention is not limited to this. The present invention can also be applied to a permanent magnet type synchronous motor having a surface magnet structure (SPM: Surface Permanent Magnet) in which permanent magnets are arranged on the outer peripheral surface of the rotor core.
Furthermore, in the first to third embodiments, the case where the stator core 2 has 12 slots and the rotor core 3 has four magnetic poles 12 has been described. However, the present invention is not limited to this. The number of slots of the stator core 2 and the number of magnetic poles of the rotor core 3 can be set to any combination that can drive the synchronous motor to rotate.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type synchronous motor, 2 ... Stator core, 3 ... Rotor core, 4 ... Frame, 11 ... Split core, 12 ... Stator yoke, 13 ... Teeth part, 14 ... Hat part, 15 ... Slot, 16 ... excitation coil, 21 ... rotor core plate, 22 ... magnetic pole, 24 ... slot, 25 ... permanent magnet, 31 ... recess

Claims (6)

A permanent core comprising a stator core formed of laminated steel sheets, a rotor core having a permanent magnet rotatably disposed in the fixed core, and a cylindrical frame that supports the outer peripheral surface of the stator core. A magnet-type synchronous motor,
A permanent magnet type synchronous motor characterized in that stress relaxation portions that are in a non-contact state with the stator core are formed at a predetermined interval in the circumferential direction on an inner peripheral surface facing the stator core of the frame. .   The permanent magnet type synchronous motor according to claim 1, wherein the stress relaxation portion is formed of a concave portion.   3. The permanent magnet type synchronous motor according to claim 1, wherein the number of slots of the stator core and the number of the stress relaxation portions are set to the same number.   4. The permanent magnet synchronous motor according to claim 3, wherein the stator core is configured by connecting a plurality of divided cores divided in a circumferential direction in an annular shape.   4. The permanent magnet synchronous motor according to claim 1, wherein the stress relaxation portion is filled with a synthetic resin material. 5.   6. The permanent magnet type synchronous motor according to claim 1, wherein the stator core includes a stress relaxation portion that is in a non-contact state with an inner peripheral surface of the frame on an outer peripheral surface. 7. .

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