JP6379132B2 - Permanent magnet synchronous machine - Google Patents

Description

  The present invention relates to a permanent magnet synchronous machine.

  In the permanent magnet synchronous machine, an interior permanent magnet (hereinafter referred to as “IPM”) structure in which a permanent magnet is embedded in a rotor is widely adopted. Ferrite magnets that are inexpensive and can be stably procured have begun to be used for permanent magnets embedded in permanent magnet synchronous machines having an IPM structure.

  However, the performance of a permanent magnet is expressed by two physical quantities, ie, residual magnetic flux density and coercive force, and the residual magnetic flux density and coercive force of a ferrite magnet are about 1/3 of a neodymium magnet. Therefore, when a neodymium magnet that is widely used at present is replaced with a ferrite magnet, the performance is significantly reduced.

  Patent Document 1 discloses a permanent magnet-embedded rotor having an accommodation hole in which the permanent magnet is embedded in a substantially concave shape, and has an accommodation hole in which the outer peripheral surface of the rotor is widened toward the inner diameter of the rotor. . According to Patent Literature 1, while increasing the magnetic flux generation area and increasing the core cross-sectional area of the radial outer periphery of the permanent magnet, the reluctance torque is actively utilized to improve performance. .

Japanese Patent No. 4666726

  In the permanent magnet synchronous machine having the IPM structure, a yoke portion called a rib is provided on the outer peripheral side of the permanent magnet accommodation hole in order to hold the permanent magnet by the rotor.

  When the rotor rotates, centrifugal force acts on the permanent magnet and the rotor core. This centrifugal force acts as a bending moment on the rib. Therefore, in order to give the rib strength that does not break or deform during rotation, it is necessary to widen the width of the rib.

  On the other hand, in the magnetic flux of the permanent magnet, there exists a leakage magnetic flux that leaks to the rib and does not generate torque. The amount of leakage flux increases until the rib is magnetically saturated. In other words, the magnetic flux that causes the magnetic saturation of the rib becomes the leakage magnetic flux. When a magnet having a low residual magnetic flux density such as a ferrite magnet is adopted as the permanent magnet, a relatively large proportion of leakage magnetic flux is required before the rib causes magnetic saturation, and the main magnetic flux is relatively reduced. Therefore, in order to reduce the ratio of the leakage magnetic flux to the rib, it is necessary to narrow the width of the rib.

  That is, there is a contradictory relationship between increasing the width of the rib to ensure the strength of the rib and decreasing the width of the rib to reduce the ratio of leakage magnetic flux to the rib. Therefore, in the structure of the rotor of Patent Document 1, in order to ensure the strength of the rib, the width of the rib must be widened, and the leakage magnetic flux increases.

  An object of this invention is to reduce a leakage magnetic flux, ensuring the intensity | strength of a rib.

The permanent magnet synchronization of the present invention is configured in a substantially concave shape in which the rotor outer peripheral surface side is widened and narrowed toward the rotor inner diameter side, and a magnet housing hole in which the permanent magnet is disposed, and a radial direction of the magnet housing hole A rotor core positioned on the outer peripheral side, a rib positioned on the interpole side of the rotor core and on a radially outer peripheral side of the magnet receiving hole, and positioned on the interpole side of the magnet receiving hole and the rib A connecting portion, wherein the rib is a connecting portion side rib located on the connecting portion side, a rotor core side rib located on the rotor core side, the connecting portion side rib and the rotor core side. A central rib located between the ribs, and a projecting portion located on a radial outer diameter side of the rotor core side rib and the rotor core, and the connecting portion in a portion connected to the connecting portion The width of the side rib is wider than the width of the central rib at the central portion, The width of the rotor core rib in the portion leading to the rotor core, the connecting portion and the connecting portion side rib wider than the width of the portion leading to the centrifugal force direction between the permanent magnet and the rotor core gaps in the narrower than the gap in the centrifugal direction between said rib and said permanent magnet, the permanent magnet is constituted by integrally without being split in the circumferential direction per pole, the magnet containing hole in said central rib The shape on the side has a linear shape, and the shape on the magnet accommodation hole side in the connecting portion side rib has a curved shape that protrudes outside the magnet accommodation hole, and the rotor core The shape of the side rib on the side of the magnet accommodation hole has a curved shape that protrudes outward from the magnet accommodation hole.

  According to the present invention, it is possible to reduce the leakage magnetic flux while ensuring the strength of the rib.

1 is an overall view of a permanent magnet synchronous machine according to a first embodiment of the present invention. 1 is a partial cross-sectional view of one pole of a permanent magnet synchronous machine according to a first embodiment of the present invention. The fragmentary sectional view for one pole of the permanent magnet synchronous machine by the 2nd example of the present invention. The stress distribution figure at the time of rotation of a permanent magnet synchronous machine.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall view of a permanent magnet synchronous machine according to a first embodiment of the present invention. The permanent magnet synchronous machine includes a rotor 1 and a stator 30. The rotor 1 includes a permanent magnet housing hole 4 configured to protrude radially inward, a rotor core 2 located on the radially outer side of the permanent magnet housing hole 4, and a pole-to-pole side of the rotor core 2. And the rib 6 located in the radial direction outer peripheral side of the permanent magnet accommodation hole 4 is provided.

  FIG. 2 is a partial cross-sectional view of one pole of the permanent magnet synchronous machine in the first embodiment of the present invention. The permanent magnet 3 is disposed in the permanent magnet accommodation hole 4. The permanent magnet accommodation hole 4 and the adjacent permanent magnet accommodation hole 4 are connected by a connecting portion 11.

  Normally, the magnetic flux generated from the permanent magnet 3 passes through the rotor core 2, and passes through the space (hereinafter referred to as “gap 31”) 31 between the rotor 1 and the stator 30 to the stator 30. To generate torque. The magnetic flux that contributes to the generation of this torque is called the main magnetic flux or effective magnetic flux.

  On the other hand, the magnetic flux of the permanent magnet adjacent to the rib 6 leaks to the rib 6 having a relatively small magnetic resistance compared to the gap 31 and does not generate torque. For this reason, the magnetic flux that does not contribute to the generation of torque is called leakage magnetic flux.

  When the rib 6 is magnetically saturated by the leakage magnetic flux 9, the magnetic resistance becomes the same as the gap 31. That is, when the leakage magnetic flux 9 reaches a certain level, the remaining magnetic flux becomes the main magnetic flux 10 that passes through the gap 31.

  The permanent magnet 3 is integrally formed without being divided in the circumferential direction per pole, and has at least two bending points 42a and 42b in the circumferential direction per pole. The side portions 41a and 41b extend from the bending points 42a and 42b as the starting ends in a direction perpendicular to the magnetization direction and toward the end of the pole.

  Here, at the end portion between the poles of the permanent magnet housing hole 4, the length from the outer peripheral side end portion of the permanent magnet housing hole 4 on the pole center side to the end of the rotor 1 (hereinafter referred to as “the width of the rib 6 b”). .) L1, the length from the outer peripheral side end of the permanent magnet housing hole 4 on the pole-to-pole side to the outer peripheral side end of the rotor 1 (hereinafter referred to as “width of the rib 6c”) L2, in the linear direction of the rib 6 The length from the outer peripheral side end of the permanent magnet housing hole 4 to the outer peripheral side end of the rotor 1 at the point (hereinafter referred to as “the width of the rib 6a”) L0.

  When the rotor 1 rotates, centrifugal force acts on the permanent magnet 3 and the rotor core 2. With respect to this centrifugal force, the connecting portions 11 located at both ends function as fulcrums and the ribs 6 located at both ends function as beams. Since the rib 6c is closer to the connecting portion 11 as a fulcrum than the ribs 6a and 6b, the bending moment applied to the rib 6c is larger than that of the ribs 6a and 6b. Therefore, as shown in FIG. 4, the stress concentration on the rib 6c is larger than that of the rib 6a.

  In the present embodiment, the rigidity of the rib 6c is made higher than that of the rib 6a by making the width L2 of the rib 6c wider than the width L0 of the rib 6a according to the distribution of the bending moment acting on the rib 6.

  On the other hand, since the rib 6b is in a position where it is connected to the rotor core 2, the width changes abruptly. Therefore, stress concentrates near the rib 6b, and high stress is locally applied. Therefore, as shown in FIG. 4, the stress concentration in the rib 6b is larger than that in the rib 6a.

  Therefore, in the present embodiment, since the width L1 of the rib 6b is wider than the width L0 of the rib 6a, the shape of the rib 6 is prevented from changing suddenly and stress concentration is avoided.

  In this way, by adjusting the width of the rib 6 according to the force acting on the rib 6, it is possible to avoid widening the entire width of the rib 6 more than necessary, and to leak the magnetic flux more than to make the width of the rib 6 uniform. Can be reduced.

  Only one of the width L1 of the rib 6b larger than the width L0 of the rib 6a and the width L2 of the rib 6c larger than the width L0 of the rib 6a may be employed.

  Furthermore, the width of the rotor core 2 in the radial direction of the permanent magnet housing hole 4 that is convex inward in the radial direction employed in this embodiment is larger than that of the linear magnet housing hole. For this reason, since the width in the radial direction changes abruptly between the rotor core 2 and the rib 6, the stress is concentrated in the vicinity of 6b. Therefore, in this embodiment, the width L1 of the rib 6b is made larger than the width L2 of the rib 6c, and the area A1 of the rib 6 from the midpoint of the rib 6 in the linear direction to the pole center side is It is larger than the area A2 of the rib 6 from the point to the inter-electrode side.

  Further, at the end portion between the poles of the permanent magnet housing hole 4, the pole center side is an arc having a radius R1, and the pole side is an arc having a radius R2, so that the rib 6 The width is adjusted.

  Further, by making the total value of the radius R1 and the radius R2 smaller than the magnetization direction thickness T2 of the magnet, a straight portion is provided in the rib 6 to avoid stress concentration on the rib 6a.

  Further, the rotor 1 is provided with a protruding portion 12 on the radially outer peripheral side of the rotor core 2. By providing the protruding portion 12, the width L1 of the rib 6b can be further increased, and the rigidity of the rib 6b where stress concentrates is increased. The width of the projecting portion 12 on the outer peripheral side in the radial direction is set to be equal to or less than half of the width L1 of the rib 6b.

  Moreover, by providing the protrusion part 12, an iron core cross-sectional area becomes large and a reluctance torque can also be increased.

  In order to further increase the reluctance torque, the width of the protruding portion 12 on the outer peripheral side in the radial direction may be made more than half the width L1 of the rib 6b.

  The rotor core 2 is composed of laminated steel plates, dust cores, or amorphous metals stacked in the axial direction.

  Moreover, although the side parts 41a and 41b of the permanent magnet 3 demonstrated the case where it was a structure perpendicular | vertical with respect to a magnetization direction and extended toward the edge part side of a pole, the curved structure curved so that it may become convex inside radial direction It is good. Or you may make it comprise the side parts 41a and 41b by a some side part so that it may protrude in the radial direction inner side.

  In addition, the contact points 45 and 46 between the bending point 42 of the permanent magnet 3 and the rotor core 2 may be formed in an arc or a polygonal line.

  Moreover, although the ferrite magnet is mentioned as an example as the permanent magnet 3, it is not limited only to a ferrite magnet.

  Moreover, although the inner rotation type rotor has been described, the present invention can also be applied to an outer rotation type rotor.

  FIG. 3 is a partial cross-sectional view of one pole of a permanent magnet synchronous machine according to a second embodiment of the present invention.

  The width T1 of the magnetization direction clearance 8a in the central portion 40 of the pole is wider than the width T2 of the magnetization direction clearance 8b in the side portions 41a and 41b.

  Centrifugal force acts on the permanent magnet 3 and acts on the rib 6 as a bending moment. By making the width T1 of the magnetization direction clearance 8a wider than the width T2 of the magnetization direction clearance 8b, the centrifugal force acting on the central portion 40 of the permanent magnet 3 acts on the rotor core 2 via the side portions 41a and 41b.

  The side portions 41 a and 41 b are located closer to the connecting portion 11 than the central portion 40. Therefore, the bending moment acting on the rib 6 due to the centrifugal force of the central portion 40 of the permanent magnet 3 can be weakened. Therefore, since the strength of the rib 6 can be afforded, the rib width can be narrowed and the ratio of the leakage magnetic flux to the rib 6 can be reduced.

  Furthermore, by increasing the linear length W2 of the side portions 41a and 41b of the permanent magnet 3 to be longer than the linear length W1 of the central portion 40, the proportion of the permanent magnet 3 located near the connecting portion 11 can be increased. it can. Therefore, the bending moment acting on the rib 6 due to the centrifugal force of the permanent magnet 3 can be weakened, the rib width can be narrowed, and the ratio of the leakage magnetic flux to the rib 6 can be reduced.

  The width T1 of the magnetization direction clearance 8a is made wider than the width T2 of the magnetization direction clearance 8b, and the linear length W2 of the side portions 41a and 41b of the permanent magnet 3 is longer than the linear length W1 of the central portion 40. It is good also as a structure which employ | adopts only either, without using together.

  As described above, the permanent magnet synchronous machine of the present invention is configured to protrude radially inward, and includes a magnet housing hole in which the permanent magnet is disposed, and a rotor located on the radially outer side of the magnet housing hole. An iron core, a rotor core and a rib positioned on the outer peripheral side in the radial direction of the magnet housing hole, and a connecting portion positioned on the magnet housing hole and the interelectrode side of the rib, the rib being connected A connecting part side rib located on the part side, a rotor core side rib located on the rotor core side, and a central rib located between the connecting part side rib and the rotor core side rib, the connecting part The width of the side rib is wider than the width of the central rib.

  In the permanent magnet synchronous machine of the present invention, the width of the rotor core side rib is wider than the width of the central rib.

  In the permanent magnet synchronous machine of the present invention, the width of the rotor core side rib is wider than the width of the connecting portion side rib.

  Further, in the permanent magnet synchronous machine of the present invention, at the end portion between the poles of the magnet accommodation hole, the shape at the pole center side is an arc of radius R1, the shape at the pole side is an arc of radius R2, and the radius R1 The total value of R2 is smaller than the thickness in the magnetization direction of the permanent magnet.

  Moreover, the permanent magnet synchronous machine of this invention is provided with the protrusion part located in the radial direction outer-diameter side of a rotor core side rib and a rotor core.

  In the permanent magnet synchronous machine of the present invention, the permanent magnet has a central portion and side portions located at both ends of the central portion, and the clearance in the magnetization direction of the central portion is larger than the clearance in the magnetization direction of the side portion. Is also big.

  In the permanent magnet synchronous machine of the present invention, the permanent magnet has a central portion and side portions located at both ends of the central portion, and the length in the direction perpendicular to the magnetization direction of the side portion is a straight line with the central portion. Longer than the length.

1 Rotor 2 Rotor core 3 Permanent magnet 4 Permanent magnet insertion hole 5 Shaft hole 6 Rib
6a Central rib
6b Rotor core side rib
6c Connecting portion side rib 7 Clearance between end portions 8 between magnetism direction Clearance 9 Leakage magnetic flux 10 Main magnetic flux 11 Connecting portion 30 Stator 31 Gap 41 Side portion 42 Bending point 45, 46 Contact between bending point 42 and rotor core 2 Point 71 Action point 72 of centrifugal force 70 Distance 73 from stress concentration part 73 to action point 71 Stress concentration part

Claims (4)

A magnet housing hole in which a permanent magnet is disposed, the rotor outer peripheral surface side being configured to be a substantially concave shape widened toward the rotor inner diameter side, and
A rotor core located on the radially outer side of the magnet housing hole;
A rib located between the poles of the rotor core and the radially outer periphery of the magnet housing hole;
A coupling portion located on the inter-electrode side of the magnet accommodation hole and the rib,
The rib is
A connecting portion side rib located on the connecting portion side;
A rotor core side rib located on the rotor core side;
A central rib located between the connecting portion side rib and the rotor core side rib;
The rotor core-side rib and the protruding portion located on the radially outer diameter side of the rotor core;
Configured with
The width of the connecting portion side rib in the portion connected to the connecting portion is wider than the width of the central rib in the central portion,
The width of the rotor core side rib in the part connected to the rotor core is wider than the width of the connection part side rib in the part connected to the connection part,
The gap in the centrifugal force direction between the permanent magnet and the rotor core is narrower than the gap in the centrifugal force direction between the permanent magnet and the rib,
The permanent magnet is integrally formed without being divided in the circumferential direction per pole,
The shape of the central rib on the magnet receiving hole side has a linear shape,
The shape on the magnet accommodation hole side in the connecting portion side rib has a curved shape that is convex to the outside of the magnet accommodation hole,
The permanent magnet synchronous machine in which the shape on the magnet accommodation hole side in the rotor core side rib has a curved shape that protrudes outward from the magnet accommodation hole.   The permanent magnet synchronous machine according to claim 1, wherein the permanent magnet has at least two bending points. The permanent magnet has a central portion located between the two bending points, and side portions located at both ends of the central portion,
The minimum gap between the permanent magnet in the central portion and the rotor core is wider than the minimum gap between the permanent magnet in the side portion and the rotor core. 2. A permanent magnet synchronous machine according to 2. The length of the said permanent magnet from the edge of the said side part to the near bending point is larger than the length between the said two bending points of the said center part, The Claim 3 characterized by the above-mentioned. Permanent magnet synchronous machine.