JP7731318B2 - Rotor of a synchronous reluctance motor - Google Patents

Description

This disclosure relates to a rotor for a synchronous reluctance motor.

A synchronous reluctance motor generates rotational force by generating reluctance torque in the rotor using magnetic flux generated by passing current through the stator coil. The rotor core of a synchronous reluctance motor is made of laminated electromagnetic steel sheets and has a cylindrical shape. The rotor core of a synchronous reluctance motor has a characteristic salient shape to increase reluctance torque and improve electrical performance. Specifically, the rotor core has multiple flux barriers arranged radially to block magnetic flux in the q-axis direction.

Synchronous reluctance motors use a structure in which balance rings or end plates are arranged to abut both axial ends of the rotor core. The purpose of the balance rings or end plates is to adjust the balance and suppress axial deformation of the rotor core. In Patent Document 1, balance rings are provided on both axial outer sides of a rotor core that has multiple slits that act as flux barriers. The balance rings are composed of a first ring made of a magnetic material and a second ring made of a non-magnetic material, and the outer periphery of the first ring and the inner periphery of the second ring are joined by shrink fitting or adhesive. The first ring is cross-shaped so as to avoid the magnetic path between the slits, and abuts the rotor core at parts other than the magnetic path.

JP 2015-104224 A

However, in Patent Document 1, the first ring, which is made of a magnetic material, abuts against the rotor core. Therefore, in order to suppress leakage flux and eddy current loss in the rotor core, the first ring is given a complex shape, such as a cross shape, which poses a problem of increased costs.

The present disclosure has been made in light of the above, and aims to provide a rotor for a synchronous reluctance motor that has a simple structure, is low cost, and is capable of achieving balance adjustment and suppressing axial deformation of the rotor core.

To solve the above-mentioned problems and achieve the object, the rotor of a synchronous reluctance motor of the present disclosure includes a cylindrical rotor core formed by laminating multiple magnetic steel plates, with magnetic poles formed by multiple radially arranged flux barriers; disk-shaped balance rings made of a magnetic material disposed at both axial ends of the rotor core; and a non-magnetic spacer sandwiched between the balance rings and the rotor core so that one surface abuts against the flux barriers in the rotor core and the other surface abuts against the balance ring. The spacer has an annular shape with a discontinuous end , and is made of a single or multiple rounds of bar material. The ends of the bar material protrude toward the balance ring, and the balance ring has positioning holes into which the protruding ends of the bar material are inserted.

The rotor of the synchronous reluctance motor disclosed herein has the advantage of being able to achieve balance adjustment and suppress axial deformation of the rotor core with a simple structure and low cost.

FIG. 1 is a schematic front view in cross section showing the configuration of a synchronous reluctance motor according to a first embodiment of the present invention; FIG. 10 is a schematic front view in cross section showing the configuration of another synchronous reluctance motor according to the first embodiment; FIG. 1 is a cross-sectional view showing a schematic configuration of a stator and a rotor of a synchronous reluctance motor according to a first embodiment. FIG. 1 is a cross-sectional view showing the configuration of a synchronous reluctance motor of a comparative example. FIG. 1 is a cross-sectional view showing a configuration of a rotor of a synchronous reluctance motor according to a first embodiment; FIG. 1 is a perspective view showing a configuration of a balance ring according to a first embodiment; FIG. 1 is a perspective view showing a configuration of a spacer according to a first embodiment; Schematic diagram for explaining a method for manufacturing a spacer according to the first embodiment. FIG. 10 is a perspective view showing another configuration of the balance ring according to the first embodiment; FIG. 10 is a perspective view showing still another configuration of the balance ring according to the first embodiment; FIG. 10 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to a second embodiment. FIG. 10 is a perspective view showing the configuration of a spacer according to a second embodiment; Schematic diagram for explaining a method for manufacturing a spacer according to the second embodiment. FIG. 10 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to a third embodiment. FIG. 10 is a perspective view showing the configuration of a spacer according to a third embodiment; Schematic diagram for explaining a manufacturing method of a spacer according to the third embodiment. FIG. 10 is a perspective view showing the configuration of a balance ring according to a fourth embodiment. FIG. 10 is a perspective view showing the configuration of a balance ring and a spacer according to a fourth embodiment; FIG. 10 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to a fifth embodiment. FIG. 13 is a perspective view showing the configuration of a spacer according to a fifth embodiment. FIG. 13 is a perspective view showing another configuration of the spacer according to the fifth embodiment. FIG. 13 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to a sixth embodiment. FIG. 13 is a perspective view showing the configuration of a balance ring according to a sixth embodiment. FIG. 13 is a perspective view showing a configuration of a spacer according to a sixth embodiment. FIG. 13 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to a seventh embodiment. FIG. 13 is a perspective view showing the configuration of a spacer according to a seventh embodiment; FIG. 19 is a cross-sectional view showing the configuration of a rotor of a synchronous reluctance motor according to an eighth embodiment of the present invention. FIG. 13 is a perspective view showing the configuration of a spacer according to an eighth embodiment. FIG. 13 is a perspective view showing the configuration of a balance ring according to a ninth embodiment. FIG. 13 is a perspective view showing the configuration of a spacer according to a ninth embodiment;

The rotor of a synchronous reluctance motor according to an embodiment is described in detail below with reference to the drawings.

Embodiment 1.
1 is a schematic front cross-sectional view showing the configuration of a synchronous reluctance motor 10 according to embodiment 1. Synchronous reluctance motor 10 includes a housing 11, a stator 20, and a rotor 30. Housing 11 has a cylindrical frame 12 with a bottom and a bracket 13 that closes an opening of frame 12. Stator 20 is fixedly fitted within the cylindrical portion of frame 12. Rotor 30 is disposed on the inner periphery of stator 20 and is supported by the bottom of frame 12 and bracket 13 via bearings 14 so as to be rotatable about a rotation axis 33.

Figure 2 is a schematic half-sectional front view showing the configuration of another synchronous reluctance motor 10a according to embodiment 1. The synchronous reluctance motor 10a includes a housing 11a, a stator 20, and a rotor 30. The housing 11a of the synchronous reluctance motor 10a shown in Figure 2 has a cylindrical frame 12a rather than a bottomed cylinder, and two brackets 13 that close the openings at both ends of the frame 12a.

Figure 3 is a cross-sectional view showing the schematic configuration of the stator 20 and rotor 30 of the synchronous reluctance motor 10 according to embodiment 1. The stator 20 includes a stator core 21 and a stator coil 22. The stator core 21 includes a plurality of teeth 21a arranged in an annular shape and a back yoke 21b connecting the teeth 21a at their outer periphery. The stator coil 22 is wound around each of the teeth 21a. The stator core 21 is made of a thin magnetic plate (primarily a silicon steel plate). The stator core 21 is formed into a cylindrical shape by laminating multiple annular steel plates, each having a plurality of teeth 21a formed at equal intervals on its inner circumferential surface. The laminated steel plates are joined together in the lamination direction by welding or crimping the outer periphery. The stator coil 22 receives an AC current from an AC power supply (e.g., an inverter) (not shown) and generates a rotating magnetic field.

The rotor 30 has a rotor core 31 and a rotating shaft 33 that passes through the center of the rotor core 31. The rotor core 31 is formed into a cylindrical shape by laminating multiple annular magnetic steel plates, which are joined together in the lamination direction by welding or crimping the outer periphery. The rotor core 31 has multiple flux barriers 32, which are arc-shaped grooves arranged radially. The multiple flux barriers 32 are arranged at intervals in multiple layers per magnetic pole to block magnetic flux 41 that is ineffective for rotation of the rotor core 31 (q-axis magnetic flux) and allow magnetic flux 40 that is effective for rotation to pass through. In other words, a magnetic pole is formed by the multiple flux barriers 32 arranged radially. Each flux barrier 32 is formed in an arc shape that convexly faces radially inward of the rotor core 31. The rotor core 31 has an iron core portion 32a sandwiched between the flux barriers 32. Multiple flux barriers 32 provided on the rotor core 31 form a d-axis 42, which is the direction in which magnetic flux does not flow easily, and a q-axis 43, which is the direction in which magnetic flux flows easily.

As mentioned above, when AC current is supplied to the stator coil 22 from an AC power supply (not shown), a magnetic field is generated inside the stator 20. Depending on the polarity of the magnetic field generated by the stator coil 22, magnetic flux is generated that passes through the magnetic path 44 formed by the rotor core 31. The magnetic path 44 represents a magnetic path for one magnetic pole. The magnetic flux passing through the magnetic path 44 circulates through the core portion 32a sandwiched between the flux barriers 32 of the rotor core 31, the teeth portion 21a of the stator core 21, and the back yoke portion 21b. The AC current supplied from the AC power supply changes the polarity of the magnetic field generated by the stator coil 22 so that it rotates around the rotation axis 33. The rotor 30 rotates around the rotation axis 33 due to reluctance torque generated when the rotor core 31, which is a magnetic material, is attracted to the poles of the magnetic field.

Figure 4 is a cross-sectional view showing the configuration of a comparative example synchronous reluctance motor. Figure 4 corresponds to the cross-sectional view taken along line IV in Figure 3. Balancing rings 34 made of a magnetic material are arranged on both sides of a rotor core 31 having multiple flux barriers 32 and multiple core portions 32a. The balancing rings 34 are used for balance adjustment and to secure the rotor core 31. Here, the path of the magnetic flux ineffective for rotation (q-axis magnetic flux) 41 is blocked by multiple flux barriers 32, resulting in high magnetic resistance on the q-axis and less magnetic flux on the q-axis than the magnetic flux effective for rotation (d-axis magnetic flux). However, if the balancing ring 34 were made of a magnetic material, axial leakage magnetic flux would occur through the balancing ring 34, as shown by arrow 46, increasing the q-axis magnetic flux and resulting in deterioration of motor characteristics such as reduced torque and increased loss.

Figure 5 is a cross-sectional view showing the configuration of the rotor 30 of the synchronous reluctance motor 10 according to embodiment 1. Figure 5 corresponds to the cross-sectional view taken along line IV in Figure 3. Figure 6 is a perspective view showing the configuration of the balance ring 50 according to embodiment 1. Figure 7 is a perspective view showing the configuration of the spacer according to embodiment 1. Figure 8 is a schematic diagram for explaining a manufacturing method of the spacer 51 according to embodiment 1.

As shown in FIG. 5, balance rings 50, which are end plates made of a magnetic material, are arranged on both sides of the rotor core 31, which has multiple flux barriers 32 and multiple core portions 32a. The balance rings 50 are disc-shaped and are used for balance adjustment and to secure the rotor core 31. As shown in FIG. 6, the surface of the balance ring 50 facing the rotor core 31 has an annular groove 50c for positioning an annular spacer 51. A spacer 51 is provided between the balance ring 50 and the rotor core 31. The spacer 51 fits into the groove 50c provided in the balance ring 50.

The balance ring 50 is made of a magnetic material and manufactured by casting or cutting. To correct the balance, the back surface 50a or side surface (radial end surface) 50b of the balance ring 50 can be removed using a tool such as a drill or end mill to create a recess, thereby shifting the center of gravity of the balance ring 50 and correcting the balance of the rotor 30. The balance ring 50 has a through hole 60 in the center for fixing the rotating shaft 33.

As shown in Figure 7, the spacer 51 has an annular shape. One surface of the spacer 51 abuts against the flux barrier 32 on the rotor core 31, and the other surface abuts against the balance ring 50, sandwiched between the balance ring 50 and the rotor core 31. As shown in Figure 8, the spacer 51 is manufactured by cutting a round bar of non-magnetic material such as aluminum or stainless steel to a certain length and plastically deforming it into an annular shape using a press, wire bender, or other method. Thus, the spacer 51 is composed of a round bar. In this specification, the term "bar" is defined to include not only the concept of rod material but also the concept of wire material. The thickness of the bar material and the diameter of the annular shape can be selected arbitrarily. Because the spacer 51 is manufactured by bending a round bar into an annular shape, which is a form of plastic deformation, a seam 51a is always present as a discontinuous portion. The end faces of the seam 51a may be in contact, or there may be a gap without contact. In order to restrain the rotor core 31 in the axial direction and prevent imbalance of the spacer 51, it is preferable that the gap created by the joint 51a be small.

Figure 9 is a perspective view showing another configuration of the balance ring 50 according to embodiment 1. Figure 10 is a perspective view showing yet another configuration of the balance ring 50 according to embodiment 1. The balance ring 50 shown in Figure 9 has an annular protrusion 50d on the outer periphery of the balance ring 50 to position and fix the spacer 51. The balance ring 50 shown in Figure 10 has two parallel rows of annular protrusions 50e on the outer periphery of the balance ring 50 to position and fix the spacer 51.

In this way, in embodiment 1, a non-magnetic spacer 51 in a circular ring shape with a seam 51a is disposed between the balance ring 50 and the rotor core 31. In other words, the spacer 51 is formed by plastically deforming a round bar material, which is readily available, inexpensive, and easy to process, into a circular ring shape. This results in good material yield, makes processing easy, and allows the spacer to be formed inexpensively. Therefore, balance adjustment and suppression of axial deformation of the rotor core 31 can be achieved with a simple structure and at low cost.

Embodiment 2.
Fig. 11 is a cross-sectional view showing the configuration of rotor 30 of synchronous reluctance motor 10 according to embodiment 2. Fig. 12 is a perspective view showing the configuration of spacer 52 according to embodiment 2. Fig. 13 is a schematic diagram for explaining a method for manufacturing spacer 52 according to embodiment 2. In embodiment 2, spacer 52 has a rectangular cross-sectional shape. The same balance ring 50 as in embodiment 1 is used, but the positions and dimensions of groove 50c, annular protrusion 50d, and annular protrusion 50e must be determined according to the dimensions of rectangular spacer 52.

As in embodiment 1, the spacer 52 is manufactured from a non-magnetic material such as aluminum or stainless steel by cutting a square bar stock to a fixed length and plastically deforming it into a ring in the flatwise direction 52b using a press, wire bender, or other method. In this way, the spacer 52 in embodiment 2 is flatwise wound. The thickness and width of the bar stock and the diameter of the ring can be selected as desired.

Since the spacer 52 is manufactured by plastically deforming a square bar into an annular shape, a seam 52a is always present. The end faces of the seam 52a may be in contact, or there may be a gap without contact. In order to restrain the rotor core 31 in the axial direction and prevent imbalance of the spacer 52, it is preferable that the gap created by the seam 52a be small.

According to embodiment 2, the spacer 52 is constructed by flat-wounding square bar material, which allows for easy bending. This effectively increases the distance between the balance ring 50 and the rotor core 31, allowing for improved magnetic properties using a small amount of non-magnetic material.

Embodiment 3.
Fig. 14 is a cross-sectional view showing the configuration of rotor 30 of synchronous reluctance motor 10 according to embodiment 3. Fig. 15 is a perspective view showing the configuration of spacer 53 according to embodiment 3. Fig. 16 is a schematic diagram for explaining a method for manufacturing spacer 53 according to embodiment 3. In embodiment 3, spacer 53 has a rectangular cross-sectional shape. The same balance ring 50 as in embodiment 1 is used, but the positions and dimensions of groove 50c, annular protrusion 50d, and annular protrusion 50e must be determined according to the dimensions of rectangular spacer 53.

As in embodiment 1, the spacer 53 is manufactured from a non-magnetic material such as aluminum or stainless steel by cutting a square bar stock to a fixed length and plastically deforming it into a ring shape in the edgewise direction 53b using a press, wire bender, or other method. In this way, the spacer 53 in embodiment 3 is edgewise wound. The thickness and width of the bar stock and the diameter of the ring can be selected as desired.

Since the spacer 53 is manufactured by plastically deforming a square bar into an annular shape, a seam 53a is always present. The end faces of the seam 53a may be in contact, or there may be a gap without contact. In order to restrain the rotor core 31 in the axial direction and prevent imbalance of the spacer 53, it is preferable that the gap created by the seam 53a be small.

According to embodiment 3, the spacer 53 is constructed by edgewise winding square bar material, which allows for a large contact area between the balance ring 50 and the spacer 53, and between the rotor core 31 and the spacer 53, resulting in a stable spacer.

Embodiment 4.
Fig. 17 is a perspective view showing the configuration of a balance ring 50 according to the fourth embodiment. Fig. 18 is a perspective view showing the configurations of a balance ring 50 and a spacer 51 according to the fourth embodiment. In the fourth embodiment, the balance ring 50 has arc-shaped protrusions 50f for positioning and fixing the spacer 51, which are provided at intervals rather than around the entire periphery. The protrusions 50f are arranged in two parallel rows. The round bar material of the first embodiment is used as the spacer 51.

If protrusions 50f are provided on the balance ring 50, the distance to the rotor core 31 will be reduced by the height of the protrusions 50f, which could reduce magnetic resistance and increase leakage flux. Therefore, in embodiment 4, by positioning the protrusions 50f at the d-axis position, the distance between the balance ring 50 and the rotor core 31 can be increased at the q-axis position, effectively suppressing leakage flux.

The protrusions 50f of the balance ring 50 may be provided in only one row on the outer periphery, as shown in Figure 9. Furthermore, the spacer 51 may be made of not only round bar material, but also flatwise wound square bar material as shown in embodiment 2, or edgewise wound square bar material as shown in embodiment 3. The diameter of the round bar material used for the spacer 51, the width and thickness of the square bar material, the diameter of the spacer 51, and the number, position, and shape of the protrusions on the balance ring 50 may be selected as desired.

In this way, according to embodiment 4, it is possible to reduce the weight of the structure for positioning the spacer 51 in the balance ring 50.

Embodiment 5.
Fig. 19 is a cross-sectional view showing the configuration of rotor 30 of synchronous reluctance motor 10 according to embodiment 5. Fig. 20 is a perspective view showing the configuration of spacer 54 according to embodiment 5. Fig. 21 is a perspective view showing another configuration of spacer 54 according to embodiment 5. In embodiment 5, spacer 54 is formed by winding a round bar material over multiple turns. In other words, spacer 54 is formed from multiple turns of bar material. Since spacer 54 according to embodiment 5 is formed by winding a round bar material over multiple turns, it necessarily has two end portions 54a as discontinuous portions.

The spacers 54 may be wound tightly as shown in Figure 20, or may be spirally wound with spaces between the round bars as shown in Figure 21, allowing for a structure that covers a wide area with a small amount of material. As shown in Figure 19, the spacers 54 are sandwiched between the balance ring 50 and the rotor core 31 over multiple turns. The spacer 54 on the left side of Figure 19 shows the tightly wound spiral spacer shown in Figure 20, while the spacer 54 on the right side shows the spaced spiral spacer shown in Figure 21.

The spacer 54 may be made of not only a round bar but also a flatwise wound square bar as shown in embodiment 2 or an edgewise wound square bar as shown in embodiment 3. The balance ring 50 may have any of the following shapes: a groove 50c as shown in FIG. 6, a projection 50d on the outer periphery as shown in FIG. 9, two parallel annular projections 50e as shown in FIG. 10, or intermittently arranged projections 50f as shown in FIG. 17. The diameter of the round bar used for the spacer 54, the width and thickness of the square bar, the diameter of the spacer 54, the number of spiral turns, the spiral spacing, the number of grooves on the balance ring 50, and the number, position, and shape of the projections may be selected arbitrarily.

According to embodiment 5, the spacer 54 is constructed by wrapping a round bar material around itself multiple times, which allows for a large contact area between the balance ring 50 and the spacer 54 and between the rotor core 31 and the spacer 54, resulting in a stable spacer.

Embodiment 6.
FIG. 22 is a cross-sectional view showing the configuration of the rotor 30 of the synchronous reluctance motor 10 according to the sixth embodiment. FIG. 23 is a perspective view showing the configuration of a balance ring 50 according to the sixth embodiment. FIG. 24 is a perspective view showing the configuration of a spacer 51 according to the sixth embodiment. In the sixth embodiment, the spacer 51 has bent portions 51c at both ends, as shown in FIG. 24 . The bent portions 51c are configured to protrude toward the opposing balance ring 50, i.e., in the axial direction of the rotor 30. As shown in FIG. 23 , the balance ring 50 has holes 50g into which the bent portions 51c of the spacer 51 are inserted. By inserting the bent portions 51c at the ends of the spacer 51 into the holes 50g, the spacer 51 can be positioned on the balance ring 50. The holes 50g may be machined holes or cast holes, and the depth, size, shape, and position of the holes 50g can be determined arbitrarily.

In Figure 24, there are bent portions 51c on both ends, but it is also possible to provide a bent portion 51c on only one side. If there is a bent portion 51c on only one side, accurate positioning cannot be achieved with just the bent portion 51c on one side, so it is preferable to use a balance ring 50 that combines the groove 50c shown in Figure 6, the protrusion 50d shown in Figure 9, or the protrusion 50e shown in Figure 10 with the hole 50g.

The spacer 51 may be made of not only a round bar but also a flatwise wound square bar as shown in embodiment 2 or an edgewise wound square bar as shown in embodiment 3. Even if the spacer 51 has bent portions 51c at both ends, the balance ring 50 may use a combination of the groove 50c shown in FIG. 6, the protrusion 50d shown in FIG. 9, the protrusion 50e shown in FIG. 10, or the intermittently arranged protrusions 50f shown in FIG. 17, and the hole 50g. The diameter of the round bar used in the spacer 51, the width and thickness of the square bar, the diameter of the spacer 51, the number of spiral turns, the spiral spacing, the number of grooves on the balance ring 50, and the number, position, and shape of the protrusions may be selected arbitrarily.

According to embodiment 6, the spacer 51 is provided with a bent portion 51c, and the balance ring 50 is provided with a hole 50g into which the bent portion 51c is inserted. This allows the spacer 51 to be positioned on the balance ring 50 without using the groove 50c or the protrusions 50d and 50e, effectively increasing the distance between the balance ring 50 and the rotor core 31.

Embodiment 7.
FIG. 25 is a cross-sectional view showing the configuration of the rotor 30 of the synchronous reluctance motor 10 according to the seventh embodiment. FIG. 26 is a perspective view showing the configuration of a spacer 54 according to the seventh embodiment. In the seventh embodiment, the spacer 54 is formed by winding a round bar material multiple times, as shown in FIG. 20 . The spacer 54 has bent portions 54g at both ends. The bent portions 54g are configured to protrude toward the opposing balance ring 50, i.e., in the axial direction of the rotor 30. As shown in FIG. 25 , the balance ring 50 has holes 50g into which the bent portions 54g of the spacer 54 are inserted. By inserting the bent portions 54g at the ends of the spacer 54 into the holes 50g, the spacer 54 can be positioned relative to the balance ring 50. The holes 50g may be machined holes or cast holes, and the depth, size, shape, and position of the holes 50g can be determined as desired.

The spacers 54 may be wound tightly as shown in Figure 26, or may be spirally wound with spaces between the round bars as shown in Figure 21. The spacer 54 on the left side of Figure 25 shows the tightly wound spiral spacer shown in Figure 26, while the spacer 54 on the right side shows the spaced spiral spacer shown in Figure 21.

The spacer 54 may be made of not only round bar material, but also flatwise wound square bar material as shown in embodiment 2 or edgewise wound square bar material as shown in embodiment 3. The balance ring 50 may also use a combination of the groove 50c shown in FIG. 6, the protrusion 50d shown in FIG. 9, the protrusion 50e shown in FIG. 10, and the intermittently arranged protrusions 50f shown in FIG. 17, in addition to the holes 50g. The diameter of the round bar material used in the spacer 54, the width and thickness of the square bar material, the diameter of the spacer 54, the number of spiral turns, the spiral spacing, the number of grooves on the balance ring 50, and the number, position, and shape of the protrusions may be selected arbitrarily.

According to embodiment 7, the spacer 54 is wound multiple times and has a bent portion 54g, and the balance ring 50 has a hole 50g into which the bent portion 54g is inserted. This allows the spacer 54 to be positioned on the balance ring 50 without using the groove 50c or protrusions 50d, 50e, effectively increasing the distance between the balance ring 50 and the rotor core 31. Furthermore, the contact area between the balance ring 50 and the spacer 54 and the contact area between the rotor core 31 and the spacer 54 can be increased, resulting in a stable spacer.

Embodiment 8.
FIG. 27 is a cross-sectional view showing the configuration of the rotor 30 of the synchronous reluctance motor 10 according to the eighth embodiment. FIG. 28 is a perspective view showing the configuration of a spacer 54 according to the eighth embodiment. In the eighth embodiment, the spacer 54 is formed by winding a round bar material multiple times, as shown in FIG. 20 . The spacer 54 has a bent portion 54g at its outer peripheral end that protrudes toward the balance ring 50, and a bent portion 54h at its inner peripheral end that protrudes radially inward of the spacer 54. As shown in FIG. 27 , the balance ring 50 has a hole 50g into which the bent portion 54g of the spacer 54 is inserted. The rotating shaft 33 has a hole 33a into which the bent portion 54h of the spacer 54 is inserted. The spacer 54 can be positioned on the balance ring 50 by inserting the bent portion 54g of the spacer 54 into the hole 50g of the balance ring 50 and inserting the bent portion 54h of the spacer 54 into the hole 33a of the rotating shaft 33. The holes 50g and 33a may be machined holes or cast holes, and the depth, size, shape and position of the holes 50g and 33a may be determined arbitrarily.

The spacer 54 may be made of not only round bar material, but also flatwise wound square bar material as shown in embodiment 2 or edgewise wound square bar material as shown in embodiment 3. The balance ring 50 may also use a combination of the groove 50c shown in FIG. 6, the protrusion 50d shown in FIG. 9, the protrusion 50e shown in FIG. 10, and the intermittently arranged protrusions 50f shown in FIG. 17, in addition to the holes 50g. The diameter of the round bar material used in the spacer 54, the width and thickness of the square bar material, the diameter of the spacer 54, the number of spiral turns, the spiral spacing, the number of grooves on the balance ring 50, and the number, position, and shape of the protrusions may be selected arbitrarily.

According to embodiment 8, the spacer 54 is wound multiple times and has bent portions 54g and 54h, the balance ring 50 has a hole 50g into which the bent portion 54g is inserted, and the rotating shaft 33 has a hole 33a into which the bent portion 54h is inserted. This allows the spacer 54 to be positioned on the balance ring 50 without using grooves 50c or protrusions 50d and 50e, effectively increasing the distance between the balance ring 50 and the rotor core 31. Furthermore, the contact area between the balance ring 50 and the spacer 54 and the contact area between the rotor core 31 and the spacer 54 can be increased, resulting in a stable spacer.

Embodiment 9.
FIG. 29 is a perspective view showing the configuration of a balance ring 50 according to the ninth embodiment. FIG. 30 is a perspective view showing the configuration of a spacer 55 according to the ninth embodiment. In the ninth embodiment, as shown in FIG. 30 , the spacer 55 has a plurality of bent portions 58, which are convex portions arranged at intervals. The bent portions 58 have a V-, C-, or U-shaped protrusion and are structured to protrude toward the opposing balance ring 50, i.e., in the axial direction of the rotor 30. As shown in FIG. 29 , the balance ring 50 has a plurality of grooves 50h, which are recesses into which the bent portions 58 of the spacer 55 are fitted. The spacer 55 can be positioned on the balance ring 50 by fitting the bent portions 58 of the spacer 55 into the grooves 50h of the balance ring 50. The spacer 55 has a seam 55a as a discontinuous portion.

The grooves 50h may be machined grooves or cast grooves, and the depth, position, width, and number of the grooves 50h can be determined arbitrarily. The shape and number of the bent portions 58 can be selected arbitrarily to match the grooves 50h of the balance ring 50. Also, bent portions 51c as shown in Figure 24 may be formed at the ends of the spacer 55. Furthermore, by modifying the V-shape, springiness can be imparted in the axial direction, more effectively securing the rotor core 31. Furthermore, the spacer 55 may be made of not only round bar material, but also flatwise wound square bar material as shown in embodiment 2, or edgewise wound square bar material as shown in embodiment 3.

In this way, according to embodiment 9, the spacer 55 having multiple bent portions 58 and the balance ring 50 having multiple grooves 50h can be positioned on the balance ring 50, effectively increasing the distance between the balance ring 50 and the rotor core 31.

The configurations shown in the above embodiments are merely examples of the content of this disclosure, and may be combined with other known technologies. Parts of the configuration may also be omitted or modified without departing from the spirit of this disclosure.

10, 10a Synchronous reluctance motor, 11, 11a Housing, 12, 12a Frame, 13 Bracket, 14 Bearing, 20 Stator, 21 Stator core, 21a Teeth portion, 21b Back yoke portion, 22 Stator coil, 30 Rotor, 31 Rotor core, 32 Flux barrier, 32a Core portion, 33 Rotating shaft, 33a, 50g Hole, 34, 50 Balance ring, 40 Magnetic flux (d-axis magnetic flux), 41 Magnetic flux (q-axis magnetic flux), 42 d-axis, 43 q-axis, 44 Magnetic path, 50a Back surface, 50b Side surface, 50c, 50h Groove, 50d, 50e, 50f Protrusions, 51, 52, 53, 54, 55 Spacer, 51a, 52a, 53a, 55a Seam, 51c, 54g, 54h, 58: Bent portion, 52b: Flatwise direction, 53b: Edgewise direction, 54a: End, 60: Through hole.

Claims (7)

a cylindrical rotor core formed by laminating a plurality of magnetic steel plates, each of which has magnetic poles formed by a plurality of radially arranged flux barriers;
a balance ring having a disk shape and made of a magnetic material, the balance ring being disposed at both axial ends of the rotor core;
a non-magnetic spacer sandwiched between the balance ring and the rotor core so that one surface abuts against the flux barrier of the rotor core and the other surface abuts against the balance ring;
Equipped with
the spacer has a circular ring shape having a discontinuous portion at an end , and is made up of a rod material having one circumference or a plurality of circumferences;
the end of the bar protrudes toward the balance ring;
The balance ring has a positioning hole into which the end of the protruding bar is inserted.
A rotor for a synchronous reluctance motor. a cylindrical rotor core formed by laminating a plurality of magnetic steel plates, each of which has magnetic poles formed by a plurality of radially arranged flux barriers;
a balance ring having a disk shape and made of a magnetic material, the balance ring being disposed at both axial ends of the rotor core;
a non-magnetic spacer sandwiched between the balance ring and the rotor core so that one surface abuts against the flux barrier of the rotor core and the other surface abuts against the balance ring;
Equipped with
the spacer has a circular ring shape having a discontinuous portion at an end, and is made up of a rod material having one circumference or a plurality of circumferences;
The spacer is
One end of the rod on the outer diameter side protrudes toward the balance ring,
The other end of the rod on the inner diameter side protrudes toward the inner diameter side,
the balance ring has a positioning hole into which the protruding one end is inserted,
A rotor for a synchronous reluctance motor , wherein a rotating shaft to which the rotor core is fixed has a positioning hole into which the protruding other end is inserted . a cylindrical rotor core formed by laminating a plurality of magnetic steel plates, each of which has magnetic poles formed by a plurality of radially arranged flux barriers;
a balance ring having a disk shape and made of a magnetic material, the balance ring being disposed at both axial ends of the rotor core;
a non-magnetic spacer sandwiched between the balance ring and the rotor core so that one surface abuts against the flux barrier of the rotor core and the other surface abuts against the balance ring;
Equipped with
the spacer has a circular ring shape having a discontinuous portion which is a joint, and is made of a rod material;
the spacer has a plurality of protrusions protruding toward the balance ring,
The rotor of a synchronous reluctance motor is characterized in that the balance ring has a plurality of recesses into which the plurality of protrusions fit . 4. The rotor of a synchronous reluctance motor according to claim 1 , wherein the bar material is a round bar. 4. The rotor of a synchronous reluctance motor according to claim 1 , wherein the bar material is a flatwise wound or edgewise wound square bar. 4. The rotor of a synchronous reluctance motor according to claim 1 , wherein the balance ring has an annular groove, an annular protrusion, or two parallel rows of annular protrusions for positioning the spacer. The balance ring is for positioning the spacer.
4. The rotor of a synchronous reluctance motor according to claim 1, further comprising: arc-shaped protrusions provided intermittently in the circumferential direction; or two parallel rows of arc-shaped protrusions provided intermittently in the circumferential direction.