JP5653298B2 - Rotor of permanent magnet embedded motor - Google Patents

Description

  The present invention relates to a rotor of a permanent magnet embedded motor in which a permanent magnet is embedded in a rotor core.

In the rotor of a permanent magnet embedded motor, an insertion hole is provided in a laminated thin steel plate to insert a permanent magnet. To prevent damage to the permanent magnet during insertion or fixation, or to prevent the permanent magnet from popping out. Technology has been developed.
2. Description of the Related Art A rotor of a conventional permanent magnet embedded motor includes a nonmagnetic metal case having an insertion hole into which a permanent magnet is fitted, and means for mechanically fixing the case to a magnet fixing hole. Consists of a thin peripheral edge, an insertion hole, a thick protrusion, and a stop (see, for example, Patent Document 1).

JP 2010-239803 A

The rotor of a conventional permanent magnet embedded motor has a case in which a permanent magnet is fitted into a case composed of a thin peripheral edge, an insertion hole, a thick protrusion, and a stop, and then the case is fixed to the insertion hole. ing.
However, since such a case covers the magnetization direction of the permanent magnet by the peripheral portion, an eddy current tends to be generated in the case portion made of a metal. Further, a clearance in the magnetization direction is generated between the rotor core and the permanent magnet by the thickness of the peripheral edge portion, so that the magnetic resistance is increased. Therefore, there is a problem that the motor characteristics are deteriorated. Further, there is a problem that the permanent magnet may be damaged when the permanent magnet is fitted to the case.
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a rotor of an embedded permanent magnet motor that prevents the permanent magnet from being damaged and has excellent motor characteristics.

In the rotor of the permanent magnet embedded motor according to the present invention, the rotor core formed by laminating a plurality of electromagnetic steel sheets has a plurality of magnet insertion holes penetrating in the axial direction, A permanent magnet and a cover made of a non-magnetic material that surrounds and surrounds the two surfaces that intersect the magnetic field lines are inserted, and the radial width of the cover is set smaller than the radial width of the permanent magnet, Two surfaces of the permanent magnet on the radially inner side and the radially outer side protrude from the cover and are exposed.

  According to the rotor of the embedded permanent magnet motor of the present invention, the cover prevents the permanent magnet from being damaged, and suppresses the generation of eddy current and the increase in magnetic resistance due to the provision of the cover, thereby improving the motor characteristics. Can be achieved.

It is a top view which shows the structure of the rotor in Embodiment 1 of this invention. It is a perspective view which shows the structure of the rotor in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the rotor in Embodiment 1 of this invention. It is a perspective view explaining the structure of the permanent magnet and cover in Embodiment 1 of this invention. It is a side view of the permanent magnet arrange | positioned in the cover in Embodiment 1 of this invention. It is a figure which shows a mode that the permanent magnet and cover in Embodiment 1 of this invention are inserted in a rotor core. It is a figure which shows the mode after insertion in the rotor core of the permanent magnet and cover in Embodiment 1 of this invention. It is a figure which shows a mode that the cover in Embodiment 1 of this invention is fixed to a rotor core. It is sectional drawing which shows the structure of the rotor of another example in Embodiment 1 of this invention. It is a perspective view which shows the variation of the cross-sectional shape of the permanent magnet in Embodiment 1 of this invention. It is a perspective view which shows the variation of the cross-sectional shape of the permanent magnet in Embodiment 1 of this invention. It is a schematic diagram which shows a mode that the permanent magnet and cover in Embodiment 2 of this invention are inserted in a rotor core. It is a perspective view explaining the structure of the permanent magnet and cover in Embodiment 3 of this invention.

Embodiment 1 FIG.
1 is a plan view showing a configuration of a rotor 1 of a permanent magnet embedded motor according to Embodiment 1 of the present invention, FIG. 2 is a perspective view of the rotor 1, and FIG. 3 is a cross-sectional view of the rotor 1.
The rotor 1 includes a rotor core 2, a plurality of permanent magnets 3, and a cover 4 for the permanent magnets 3. 4 is a perspective view for explaining the configuration of the permanent magnet 3 and the cover 4, FIG. 5 is a side view showing a state in which the permanent magnet 3 is disposed in the cover 4, and FIGS. FIG. 6 is a schematic diagram showing a process of arranging the cover 4 in the magnet insertion hole 22 of the rotor core 2. 6 shows a state where the permanent magnet 3 and the cover 4 are inserted into the rotor core 2, FIG. 7 shows a state after the insertion, and FIG. 8 shows a state where the cover 4 is fixed to the rotor core after the insertion. 7 and 8 are views seen from the direction of the protrusion 42B in order to facilitate understanding of the structure of the protrusion 42B. 9 is a cross-sectional view showing a configuration of another example of the rotor according to the first embodiment, and FIGS. 10 and 11 are views showing variations in the cross-sectional shape of the permanent magnet 3. FIG.

  The rotor core 2 is configured by laminating a plurality of electromagnetic steel plates punched into a predetermined shape. A magnetic steel sheet having a thickness of about 0.1 to 0.5 mm is used. The rotor core 2 is provided with a through-hole 21 for inserting a rotating shaft at the center thereof. The rotor core 2 is provided with four magnet insertion holes 22 having a substantially rectangular cross section at equal intervals in the circumferential direction and penetrating in the axial direction.

  The permanent magnet 3 has a substantially rectangular cross section, is formed of, for example, a neodymium magnet, and is magnetized in the short direction (the direction of arrow A in FIG. 4). The permanent magnet 3 is inserted into the magnet insertion hole 22 in a state of being disposed in the cover 4, and is disposed so that the magnetization direction of the permanent magnet 3 is the radial direction of the rotor core 2. In addition, permanent magnets 3 whose polarities are reversed are arranged in adjacent magnet insertion holes 22 of the rotor core 2. The direction of the lines of magnetic force in the rotor 1 when the permanent magnet 3 is arranged in this way is indicated by an arrow B in FIG. Two surfaces on the inner side and the outer side of the permanent magnet 3 intersect with the magnetic field lines.

As shown in FIGS. 4 and 5, the cover 4 is composed of a first frame portion 41 covering two surfaces on both sides in the circumferential direction of the permanent magnet 3 and a second frame portion 42 covering two surfaces on both sides in the axial direction. 3 is formed to surround 3. The radially inner and outer surfaces, which are the two surfaces that intersect the magnetic lines of force of the permanent magnet 3, are exposed from the cover 4 without being covered by the cover 4. The first frame portion is a frame portion that covers two surfaces of the permanent magnet 3 other than the two surfaces in the axial direction other than the two surfaces that do not intersect the magnetic field lines. The second frame portion is the permanent magnet 3. It is a frame part which covers two surfaces of the axial direction of. The radial direction, the circumferential direction, and the axial direction are all directions based on the rotor core 2.
In the first embodiment, the radial widths of the first and second frame portions 41 and 42 are set to be smaller than the radial width of the permanent magnet 3, and the two surfaces on the radially inner side and the outer side of the permanent magnet 3 are framed. It is comprised so that it may protrude from the parts 41 and 42 and may be exposed.
At one end (upper side in the drawing) of the second frame portion 42, a first protrusion 42A for retaining is provided that protrudes in the radial direction. When the cover 4 is inserted into the magnet insertion hole 22 of the rotor core 2, the first protrusion 42A comes into contact with the end surface on one side (upper side in the figure) of the rotor core 2 so that the cover 4 is a magnet. It is prevented from falling out of the insertion hole 22.
A second protrusion 42B that protrudes downward in the axial direction is provided at the other end (lower side in the drawing) of the second frame part 42.

As shown in FIG. 4, the permanent magnet 3 is disposed in the cover 4 from the opening side of the cover 4. Then, as shown in FIG. 6, the cover 4 on which the permanent magnet 3 is arranged is inserted into the magnet insertion hole 22 from the second frame portion 42 side. Since the second protrusion 42B is provided so as to protrude in the axial direction, when the cover 4 is inserted into the magnet insertion hole 22, the second protrusion 42B and the inner wall surface of the magnet insertion hole 22 of the rotor core 2 are different from each other. Do not touch. Further, when the cover 4 is inserted into the magnet insertion hole 22, the exposed surface of the permanent magnet 3 is inserted by inserting one of the surfaces of the first frame portion 41 along the inner wall surface of the magnet insertion hole 22. And the inner wall surface of the magnet insertion hole 22 of the rotor core 2 can be inserted while maintaining a constant clearance, and damage to the permanent magnet 3 during insertion can be prevented.
As shown in FIGS. 7 and 8, after inserting the cover 4 into the magnet insertion hole 22 of the rotor core 2, a load is applied to the second projecting portion 42B with a press or the like, and the second projecting portion 42B is moved to its root portion. The plastic core is plastically deformed so as to be bent in the direction of the end face on the other side in the axial direction of the rotor core 2. As a result, the second protrusion 42 </ b> B and the end surface of the rotor core 2 are pressure-bonded, and the cover 4 can be fixed in the magnet insertion hole 22 of the rotor core 2. Here, the second protrusion 42B is plastically deformed so as to be crimped to the end face of the rotor core 2, but it is not always necessary to crimp. The permanent magnet 3 and the cover 4 can be fixed in the rotor core 2 by the contact between the second protrusion 42B and the rotor core 2, and the second protrusion 42B is in the end face direction of the rotor core 2. If the cover 4 is bent, the cover 4 can be prevented from falling off from the rotor core 2. By fixing the cover 4, the permanent magnet 3 disposed in the cover 4 does not fall out of the magnet insertion hole 22 and is held in the magnet insertion hole 22.
In addition, the material of the cover 4 should just be a nonmagnetic material, and may be either a metal or a nonmetal. For example, there are aluminum alloy, nonmagnetic SUS, resin, and the like.

  As described above, the rotor 1 of the first embodiment is inserted into the magnet insertion hole 22 in a state where the permanent magnet 3 is disposed in the cover 4. It can be inserted along the inner wall surface of the magnet insertion hole 22 and can be inserted while maintaining a constant clearance between the exposed surface of the permanent magnet 3 and the inner wall surface of the magnet insertion hole 22 of the rotor core 2. For this reason, the permanent magnet 3 is prevented from being damaged during insertion. Furthermore, since the two surfaces that intersect the magnetic field lines of the permanent magnet 3 are exposed from the cover 4, the clearance between the exposed surface of the permanent magnet 3 and the rotor core 2 can be minimized, and the magnetic resistance due to the clearance is reduced. Can be suppressed. Further, since the cover 4 is configured so as not to cover the two surfaces intersecting with the magnetic lines of force of the permanent magnet 3, eddy current is hardly generated in the cover 4, and a decrease in magnetic flux acting on the periphery of the permanent magnet 3 can be prevented. . And by suppressing the increase in magnetic resistance and generation | occurrence | production of an eddy current and preventing the fall of magnetic flux, a motor characteristic can be improved and it also has the effect that energy consumption can be reduced.

Further, since the permanent magnet 3 is held in the magnet insertion hole 22 by fixing the cover 4 in the magnet insertion hole 22 of the rotor core 2, a rivet for holding the permanent magnet 3 A holding member such as an end plate is unnecessary, and the problem of damage to the permanent magnet 3 due to contact with such a holding member does not occur. Since the holding member is not required, the rotor 1 can be reduced in weight and size, and the permanent magnet 3 can be held in the magnet insertion hole 22 with a simple configuration. Environmental load is also reduced.
Further, by removing the first or second protrusions 42A and 42B, the permanent magnet 3 and the cover 4 can be easily taken out, and the rotor 1 can be easily disassembled.
Furthermore, when fixing the cover 4 to the rotor core 2 by plastically deforming the second protrusion 42B and crimping it to the end face of the rotor core 2, when fixing the cover 4 to the rotor core 2, Lamination and fixing of the respective electromagnetic steel sheets constituting the rotor core 2 can be performed simultaneously, and electromagnetic steel sheet lamination processes such as punching, welding, and adhesion can be reduced.

  In the first embodiment, the case where the magnetization direction of the permanent magnet 3 is arranged to be the radial direction of the rotor core 2 has been described. However, the arrangement of the permanent magnet 3 is not limited to this. For example, as another example of the first embodiment, as shown in FIG. 9, the permanent magnet 3 may be arranged so that the magnetization direction is the circumferential direction of the rotor core 2. The direction of the magnetic lines of force in the rotor 1 when the permanent magnet 3 is arranged in this way is as shown by the arrow C in FIG. 9, and the two surfaces intersecting with the magnetic lines of the permanent magnet 3 are two surfaces on both sides in the circumferential direction. Become. Accordingly, the first frame portion 41 of the cover 4 covers the radially inner and outer surfaces which are the two surfaces that do not intersect with the magnetic lines of force of the permanent magnet 3, and the second frame portion 42 covers the two surfaces on both sides in the axial direction. The permanent magnet 3 is configured to be surrounded by the frame portions 41 and 42 so that two surfaces on both sides in the circumferential direction intersecting with the lines of magnetic force are exposed from the cover 4.

Further, in the first embodiment, the shape of the permanent magnet 3 is substantially rectangular in cross section, but is not limited to this shape.
For example, as shown in FIG. 10, the permanent magnet 5 may have a substantially bowl-shaped cross section, and the second frame portion 620 of the cover 6 is also formed to match the shape of the permanent magnet 5. When the permanent magnet 5 is magnetized in the short direction (arrow D in the figure), the direction of the magnetic force line is also the short direction, and the two surfaces intersecting the magnetic force line of the permanent magnet 5 are a saddle-shaped curved surface and its It becomes the opposite plane. The permanent magnet 5 is disposed in the cover 6 from the opening side of the cover 6, and the first frame portion 61 and the second frame portion 62 of the cover 6 are exposed so that two surfaces that intersect the magnetic lines of force of the permanent magnet 5 are exposed. Surrounded by.
For example, as shown in FIG. 11, the permanent magnet 50 may have a substantially tile-shaped cross section, and the second frame portion 620 of the cover 60 is also formed to match the shape of the permanent magnet 50. When the permanent magnet 50 is magnetized in the short direction (arrow E in the figure), the direction of the lines of magnetic force is also the short direction, and the two surfaces intersecting the lines of magnetic force of the permanent magnet 50 are tile-shaped curved surfaces. Become. The permanent magnet 50 is disposed in the cover 60 from the opening side of the cover 60, and the first frame portion 610 and the second frame portion 620 of the cover 60 are exposed so that two surfaces that intersect the magnetic lines of force of the permanent magnet 50 are exposed. Surrounded by and.

Embodiment 2. FIG.
FIG. 12 is a schematic diagram showing a state in which the cover according to Embodiment 2 of the present invention is inserted into the rotor core. The second embodiment differs from the first embodiment in the shape of the cover and the shape of the magnet insertion hole. Other portions are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted.
The cover 7 according to the second embodiment surrounds the permanent magnet 3 with a first frame portion 71 that covers two surfaces on both sides in the circumferential direction of the permanent magnet 3 and a second frame portion 72 that covers two surfaces on both sides in the axial direction. Formed. The radially inner and outer surfaces, which are the two surfaces that intersect the magnetic lines of force of the permanent magnet 3, are exposed from the cover 7 without being covered by the cover 7. The first frame portion 71 of the cover 7 is provided with a convex portion 71A extending in the axial direction, and the inner wall surfaces on both sides in the circumferential direction of the magnet insertion hole 22 of the rotor core 2 are provided with concave portions 22A extending in the axial direction. The cover 7 is fixed in the magnet insertion hole 22 of the rotor core 2 by pressing the protrusion 71A into the recess 22A.

As described above, in the rotor 1 of the second embodiment, when the cover 7 on which the permanent magnet 3 is disposed is inserted into the magnet insertion hole 22, the convex portion 71 </ b> A of the frame portion 71 is the concave portion of the magnet insertion hole 22. Since it is press-fitted into 22A and inserted, the position of the cover 7 with respect to the magnet insertion hole 22 does not shift in the circumferential direction or radial direction during insertion. For this reason, the permanent magnet 3 can be inserted while maintaining a constant clearance between the exposed surface of the permanent magnet 3 and the inner wall surface of the magnet insertion hole 22 of the rotor core 2, thereby preventing the permanent magnet 3 from being damaged.
Further, even after the cover 7 is inserted, the cover 7 is firmly fixed in the magnet insertion hole 22 by press-fitting the convex portion 71A into the concave portion 22A. Is not displaced in the magnet insertion hole 22, and the occurrence of vibration during rotation of the rotor 1 can be suppressed.
Similarly to the first embodiment, since the cover 7 is fixed in the magnet insertion hole 22 of the rotor core 2, the permanent magnet 3 is held in the magnet insertion hole 22. A holding member such as a rivet or an end plate for holding the magnet 3 is unnecessary, and there is no problem of damage to the permanent magnet 3 due to contact with such a holding member. Since the holding member is not required, the rotor 1 can be reduced in weight and size, and the permanent magnet 3 can be held in the magnet insertion hole 22 with a simple configuration. Environmental load is also reduced.
Further, as in the first embodiment, since the two surfaces that intersect the magnetic lines of force of the permanent magnet 3 are exposed from the cover 7, the clearance between the exposed surface of the permanent magnet 3 and the rotor core 2 is minimized. It is possible to suppress the increase in magnetic resistance due to the clearance. Further, since the cover 7 is configured so as not to cover the two surfaces intersecting with the magnetic lines of force of the permanent magnet 3, eddy current is hardly generated in the cover 7, and a decrease in magnetic flux acting on the periphery of the permanent magnet 3 can be prevented. . And by suppressing the increase in magnetic resistance and generation | occurrence | production of an eddy current and preventing the fall of magnetic flux, a motor characteristic can be improved and it also has the effect that energy consumption can be reduced.

Embodiment 3 FIG.
FIG. 13 is a perspective view illustrating the configuration of the permanent magnet and the cover according to Embodiment 3 of the present invention. As shown in the figure, in the third embodiment, a substantially rectangular hole 43 is provided in the second frame portion 42 of the cover 4 described in the first embodiment. In the third embodiment, four holes 43 are provided at equal intervals in both the upper and lower frame parts 42. Other portions are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted.
The flow of eddy current generated in the cover 4 is restricted by the hole 43, and the total eddy current generated in the cover 4 can be reduced.
In addition, the shape, the number, and the arrangement position of the hole 43 are not limited to this, and may be appropriately set as necessary. In the third embodiment, the hole 43 is provided in the second frame 42 on both the upper and lower surfaces. However, the hole 43 may be provided on either one of the two surfaces of the first frame 41. It is good also as a structure provided in any one or both. Moreover, it is good also as a structure which provides the hole part 43 in all the surfaces of the 1st and 2nd frame parts 41 and 42. FIG.

  As described above, the rotor 1 according to the third embodiment is provided with the hole 43 in the second frame portion 42 of the cover 4 in addition to the configuration of the first embodiment. In addition to the above effect, it is possible to further reduce the generation of eddy currents that try to cancel out the magnetic flux in the magnetization direction of the permanent magnet 3 generated in the cover 4, and to further improve the motor characteristics.

1 rotor, 2 rotor core, 3 permanent magnet, 4 cover, 5 permanent magnet,
6 cover, 7 cover, 22 magnet insertion hole, 22A recess, 42A first protrusion,
42B 2nd protrusion part, 43 hole part, 50 permanent magnet, 60 cover, 71A convex part.

Claims (7)

A rotor core formed by laminating a plurality of electromagnetic steel sheets has a plurality of magnet insertion holes penetrating in the axial direction, and the two surfaces where the permanent magnets and the permanent magnets intersect with the lines of magnetic force are exposed in the magnet insertion holes. A cover made of a non-magnetic material surrounding each other is inserted,
A permanent magnet configured such that a radial width of the cover is set smaller than a radial width of the permanent magnet, and two surfaces of the permanent magnet on the inner side and the outer side in the radial direction protrude and are exposed from the cover. Embedded motor rotor. A first protrusion that protrudes from one end of the cover in the axial direction and abuts against one end surface of the rotor core in the axial direction, and a protrusion that protrudes from the end of the cover in the other axial direction The rotor of an embedded permanent magnet motor according to claim 1, further comprising a second protrusion that contacts the other end surface of the rotor core. The axial direction recessed part provided in the inner wall of the said magnet insertion hole of the said rotor iron core, and the convex part extended in the axial direction provided in the said cover and press-fitted in the said recessed part were provided. Alternatively, a rotor of a permanent magnet embedded motor according to claim 2. The rotor of an embedded permanent magnet motor according to any one of claims 1 to 3, wherein a hole is provided in at least one surface of the cover. 5. The rotor of an embedded permanent magnet motor according to claim 1, wherein each permanent magnet has a substantially rectangular cross section. 5. The rotor of an embedded permanent magnet motor according to claim 1, wherein each of the permanent magnets has a substantially bowl shape in cross section. 5. The rotor of a permanent magnet embedded motor according to claim 1, wherein each of the permanent magnets has a substantially roof-shaped cross section.

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