Synchronous motor

Abstract

To provide a rotor of a synchronous motor capable of suppressing deterioration of a power factor, and to provide the synchronous motor.SOLUTION: The rotator 3 of the synchronous motor 1 according to the embodiment includes a shaft member 7, a central iron core 8 having an outer periphery provided with a plurality of recessed 8a portions recessed radially inward, a plurality of outer iron cores 9 disposed on the respective recessed 8a portions at a predetermined distance from the central iron core 8, and a support member 10 supporting the central iron core 8 and the plurality of outer iron cores 9. The support member 10 includes a plate-shaped portion 11 having a contact surface 10b in contact with the central iron core 8 and the plurality of outer iron cores 9, outer walls 12 rising from the plate-shaped portion 11 in the axial direction and located at outer edges of the outer iron cores 9, and inner walls 13 located between the iron cores.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a synchronous motor stator and a synchronous motor. [Background technology]

[0002] For example, a synchronous motor such as a synchronous reluctance motor has multiple air gaps in the rotor to increase the inductance difference between the d-axis and q-axis. As described in Patent Document 1, for example, the motor generally has a structure with a so-called bridge portion in which the outer peripheries of the air gaps are connected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-135878 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the bridge portion does not contribute to torque generation, and magnetic flux leakage can cause a deterioration in the power factor.

[0005] Therefore, the present invention provides a rotor for a synchronous motor and a synchronous motor that can suppress deterioration of the power factor. [Means for solving the problem]

[0006] The rotor of a synchronous motor according to an embodiment comprises a shaft member, a central core having a core-side insertion hole at its center through which the shaft member is inserted and a plurality of radially inward recesses on its outer periphery, a plurality of outer cores arranged in each recess at a predetermined distance from the central core, and a support member supporting the central core and the plurality of outer cores, the support member having a support-side insertion hole at its center through which the shaft member is inserted and a plate-shaped portion having a contact surface that comes into contact with the central core and the plurality of outer cores, an outer wall portion that rises axially from the plate-shaped portion and is located at the outer edge of the outer core, and an inner wall portion that rises axially from the plate-shaped portion and is located between the cores.

[0007] Moreover, a synchronous motor according to the embodiment includes the rotor described above. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a synchronous motor according to an embodiment. [Figure 2] 2 is a diagram showing a cross section taken along line AA and line BB in FIG. 1; [Figure 3] A diagram showing a schematic example of the configuration of the center core and outer cores. [Figure 4] FIG. 10 is a diagram schematically illustrating an example of the configuration of a support member; [Figure 5] FIG. 10 is a diagram showing a schematic view of the rotor assembly. [Figure 6] Diagram 1 showing another example of rotor configuration [Figure 7] Diagram 2 showing another example of rotor configuration [Figure 8] Diagram 3 showing another example of rotor configuration DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment will be described with reference to the drawings. As shown in Fig. 1, a synchronous motor 1 of this embodiment includes a stator 2 and a rotor 3 disposed on the inner periphery of the stator 2. This synchronous motor 1 is assumed to be a so-called synchronous reluctance motor. Note that, to make the configuration easier to understand, the iron core portion of the rotor 3 is hatched in Fig. 1 and other figures.

[0010] As shown in Fig. 2, the stator 2 has a stator core 2a formed in a generally cylindrical shape, with coils 5 mounted in a plurality of slots 4 formed to open to the inner periphery. The coils 5 are arranged along the axial direction of the stator 2, and as shown in Fig. 1, coil ends 6 are formed at both ends of the stator 2. Note that the shape and number of slots 4 shown in Fig. 2 are merely an example and are not limited to these.

[0011] The rotor 3 includes a shaft member 7, one center core 8 and multiple outer cores 9 (described later), and two support members 10 provided on both sides in the axial direction. The shaft member 7 is cylindrical and centered on the rotation axis (J), and has keys 7a that protrude outward from part of its circumferential direction. The shaft member 7 is fixed to each of the support members 10, thereby supporting the center core 8 and multiple outer cores 9 from both sides in the axial direction. Both ends of the shaft member 7 are supported by bearings (not shown), allowing the rotor 3 to rotate relative to the stator 2.

[0012] The central core 8 is formed as a powder magnetic core obtained by compressing and molding a magnetic powder. As shown in a plan view in FIG. 3, the central core 8 has a core-side insertion hole 8b in the center into which the shaft member 7 is inserted, and a plurality of recesses 8a recessed radially inward on the outer periphery. In this embodiment, the central core 8 has four curved recesses 8a evenly spaced around the periphery. Note that the configuration of the central core 8 shown in FIG. 3 is an example, and the number and shape of the recesses 8a are not limited to this.

[0013] This center core 8 has a shape like a cylinder with a diameter of L10 cut out from the outer periphery by four recesses 8a, and the length of the longest part in a plan view is L10. Furthermore, as shown in a perspective view, the center core 8 has an axial length of L11. Furthermore, the center core 8 is formed in a shape that is symmetrical in the left-right direction of the figure with respect to an imaginary line (CL1) that passes through the rotation axis (J) and the center of the key groove 8c provided in the core-side insertion hole 8b.

[0014] Outer core 9 is formed as a powder magnetic core obtained by compressing magnetic powder. Outer core 9 is arranged in each recess 8a at a predetermined radial distance from center core 8. Furthermore, multiple outer cores 9, each curved radially inward, are arranged in each recess 8a.

[0015] Specifically, in each recess 8a, outer core 9a, which is located on the innermost side, is arranged at a predetermined distance from central core 8, and outer core 9b, outer core 9c, and outer core 9d are arranged on the outer periphery thereof at predetermined distances from each other. In other words, outer cores 9 are arranged in a radially layered positional relationship in a plan view, and each outer core 9 has an axial length L11 that is the same as central core 8.

[0016] At least a portion of outer core 9 has a wider portion than the portion exposed on the outer periphery. For example, outer core 9a has a width (W2) on the inner periphery that is wider than the width (W1) of the end portion exposed on the outer periphery. This prevents outer core 9a from protruding from rotor 3 due to its shape. The same applies to outer core 9b and outer core 9c. Note that the configuration of outer core 9 shown in FIG. 3 is one example, and the number and shape of outer cores are not limited to this.

[0017] By arranging these outer cores 9 at predetermined intervals in each recess 8a of center core 8, a gap is formed between the cores in each recess 8a. In this case, each gap extends to the outer periphery of rotor 3, so rotor 3 of this embodiment has a structure that does not include a conventional bridge portion. However, since center core 8 and each outer core 9 are separate members as described above and are arranged at intervals from each other, they must be rotated together while maintaining their relative positions.

[0018] Therefore, in this embodiment, support members 10 are provided to support center core 8 and each outer core 9 from both axial ends. Support member 10 will be described below with reference to Figure 4, and to make the structure of support member 10 easier to understand, wall portions described below are conveniently hatched in the same manner as in the cross-sectional view of Figure 2.

[0019] As shown in a plan view in Fig. 4, support member 10 has a plate-shaped portion 11, an outer wall portion 12 rising axially from plate-shaped portion 11, and an inner wall portion 13 rising axially from plate-shaped portion 11. In this embodiment, since multiple outer cores 9 are provided, multiple inner wall portions 13 are also provided. Support member 10 is formed of a non-magnetic material such as austenitic stainless steel. Note that in Fig. 4, for the sake of explanation, each inner wall portion 13 is labeled a, b, and c from the inner circumferential side, but when a common description is given, they will simply be referred to as inner wall portion 13.

[0020] Plate-shaped portion 11 has a circular outer shape with a diameter (L20) and is formed into a disk shape with a predetermined thickness (L21) in the axial direction. In this embodiment, the diameter (L20) of plate-shaped portion 11 is set to be the same as the maximum diameter (L10) of center core 8. This plate-shaped portion 11 has a support-side insertion hole 10a in the center into which shaft member 7 is inserted, and has contact surfaces 10b that come into contact with center core 8 and multiple outer cores 9. In the plan view of FIG. 4, the unhatched portions excluding support-side insertion hole 10a are contact surfaces 10b.

[0021] As shown in the perspective view, outer wall portion 12 rises from plate-shaped portion 11 in the axial direction by a predetermined length (L22) and is provided at the outer edge of outer core 9. In other words, outer wall portion 12 is provided as a wall portion for supporting outer core 9 on the outermost side. Note that while Fig. 4 illustrates a configuration in which one outer wall portion 12 is provided for each recess 8a, multiple outer wall portions 12 may also be provided.

[0022] Inner wall portion 13 rises from plate-shaped portion 11 in the axial direction by a predetermined length (L22) and is provided between the iron cores. In this embodiment, inner wall portion 13 is formed in a shape that fills all the spaces between the iron cores. Therefore, for example, inner wall portion 13a, which is located on the innermost periphery, supports center core 8 from the outside and outer core 9a, which is located on the innermost periphery, from the inside. Similarly, inner wall portion 13b supports outer core 9a from the outer periphery and outer core 9b from the inside, inner wall portion 13c supports outer core 9b from the outer periphery and outer core 9c from the inside, and inner wall portion 13d supports outer core 9c from the outer periphery and outer core 9d from the inside.

[0023] Support member 10 configured as described above has key grooves 10c formed in support-side insertion holes 10a and is formed symmetrically with respect to an imaginary line (CL2) that passes through the center of key groove 10c and rotation axis (J). Therefore, as shown in perspective views 1 and 2, by rotating support member 10 180 degrees about imaginary line (CL2), the position of key groove 10c remains the same and the wall portions rise in opposite directions. This makes it possible to support center core 8 and outer cores 9 from both axial ends by using two support members 10 of the same shape.

[0024] In this embodiment, the length (L22) of each wall of the support member 10 is set to be less than half the length (L12) of the iron core. Therefore, as shown in Fig. 1, when two support members 10 are arranged at both ends in the axial direction, the support members 10 are arranged in a state where they do not contact each other, more specifically, where the tip of the wall of one support member 10 does not contact the wall of the other support member 10. As a result, a range (R) in the axial direction is formed in the rotor 3 where no support members 10 exist.

[0025] In this range (R), there is a gap (X) between the iron cores where no support member 10 is present, as shown in the cross section of line BB in Figure 2, and this gap (X) acts as a flux barrier made of air. In this case, by minimizing the length (L21) of the wall portion while ensuring the necessary strength, it is possible to make the range (R) as wide as possible.

[0026] Next, the manufacturing procedure for rotor 3 will be described. As shown in assembly process example 1 in Figure 5, center core 8 and outer core 9 are first assembled in a predetermined position to one of support members 10. Note that for the sake of explanation, Figure 5 shows the components lined up in the left-right direction, but the work can be carried out by placing support member 10 on a workbench with the wall portion facing upward, and then placing center core 8 and outer core 9 on support member 10.

[0027] Next, by assembling support member 10 on the right side in the figure, a semi-finished product is formed in which support members 10 do not contact both ends of center core 8 and each outer core 9, as shown in assembly process example 2. Then, shaft member 7 is fixed to each support member 10 in this semi-finished product by press fitting or the like, thereby manufacturing rotor 3, as shown in assembly process example 3. It is sufficient that shaft member 7 is fixed to at least each support member 10, but it may also be configured so that it is fixed to center core 8 by press fitting or the like.

[0028] Then, the rotor 3 is disposed on the inner peripheral side of the stator 2, thereby manufacturing the synchronous motor 1 shown in Fig. 1. Note that the assembly procedure shown in Fig. 5 is an example, and the procedure for assembling each member is not limited to this, and for example, each core may be assembled in a state where the shaft member 7 is fixed to one of the support members 10 in advance.

[0029] According to the embodiment described above, the following effects can be obtained. The rotor 3 of the synchronous motor 1 according to the embodiment comprises a shaft member 7, a central core 8 having a core-side insertion hole 8b at the center into which the shaft member 7 is inserted and a plurality of radially inward recesses 8a on the outer periphery, a plurality of outer cores 9 arranged in each recess 8a at a predetermined interval between them, and a support member 10 supporting the central core 8 and the plurality of outer cores 9.

[0030] The support member 10 has a plate-shaped portion 11 having a support side insertion hole 10a in the center through which the shaft member 7 is inserted and a contact surface 10b that comes into contact with the central iron core 8 and the multiple outer iron cores 9, an outer wall portion 12 that rises axially from the plate-shaped portion 11 and is located at the outer edge of the outer iron cores 9, and an inner wall portion 13 that rises axially from the plate-shaped portion 11 and is located between the iron cores.

[0031] By arranging center core 8 and each outer core 9 in a completely separated state in this way, it is possible to eliminate bridge sections that do not contribute to torque generation and that cause a deterioration in power factor due to magnetic flux leakage. In this case, by providing support member 10, it is possible to reliably maintain the positional relationship between the cores, allowing center core 8 and each outer core 9 to rotate integrally. Therefore, it is possible to manufacture a rotor 3 that can suppress a deterioration in power factor.

[0032] Furthermore, support members 10 are provided at both ends in the axial direction without contacting each other, and a space penetrating the interior of rotor 3 is formed between center core 8 and outer core 9 between two support members 10. This allows a gap to be provided inside rotor 3 within a predetermined range (R) in the axial direction. In this case, by making the predetermined range (R) as wide as possible as in the embodiment, it is expected that efficiency will improve.

[0033] Furthermore, multiple outer cores 9 are arranged in one recess 8a to form layers in the radial direction, and inner wall portion 13 is provided between each of the cores in one recess 8a. This allows outer cores 9 to be arranged in layers and multiple outer cores 9 to be reliably supported.

[0034] Outer core 9 has a portion that is wider than the portion exposed on the outer periphery. In this case, when multiple outer cores 9 are provided as in the present embodiment, it is sufficient that at least one outer core 9 has a shape that has a portion that is wider than the portion exposed on the outer periphery. This reduces the risk of outer core 9 jumping out of rotor 3.

[0035] Furthermore, when outer core 9 does not have a wide portion, as in rotor 3A shown as another configuration example 1 in Fig. 6, restricting portion 20 that restricts displacement of outer core 9 can be provided. Note that shaft member 7 is not shown in Fig. 6 and Fig. 8 described later.

[0036] In the example shown in Fig. 6, outer wall 12 is provided with restricting portions 20 that protrude from the wall surface and restrict misalignment of outer core 9c. Inner wall 13b is provided with a plurality of restricting portions 20a that are recessed from the wall surface and restrict misalignment of outer core 9b, and restricting portions 20b that protrude from the wall surface and restrict misalignment of outer core 9b. Inner wall 13c is provided with restricting portions 20c that protrude from the wall surface and restrict misalignment of outer core 9b. Note that the positions and number of restricting portions 20 shown in Fig. 6 are merely examples and are not limited to these.

[0037] As in rotor 3B shown as another configuration example 2, a gap can be provided inside outer wall 12 or inner wall 13, or multiple inner wall portions 12 and 13 can be arranged at intervals in the radial direction with gaps provided between them. For example, inner wall 13a has gap (X1) provided therein. In this case, multiple inner wall portions 13a can be provided between center core 8 and outer core 9a, and gaps can be provided between them.

[0038] Furthermore, inner wall portion 13b and inner wall portion 13c are provided between outer core 9a and outer core 9b, with a gap (X2) therebetween. In this case, inner wall portion 13b supports outer core 9a from the outer periphery, and inner wall portion 13c supports outer core 9b from the inner periphery. If strength is required, a configuration can be adopted in which connecting member 14 is provided to connect inner wall portions 13 to improve strength. This connecting member 14 may be formed integrally with the inner periphery wall portion, or may be formed separately and then assembled.

[0039] Furthermore, it is also possible to provide a plurality of outer wall portions 12 to provide a gap (X3), or to provide a gap inside the outer wall portion 12, although this is not shown in the drawings. By using such a configuration, it is possible to provide a gap in the range in the axial direction where the support member 10 is provided, that is, in the range outside the predetermined range (R) shown in Fig. 1. Note that, although the illustrated straight wall portion is exemplified in the second configuration example, a gap or a plurality of wall portions can also be provided in the case of a curved wall portion as in the first configuration example described above.

[0040] Up to this point, we have shown examples in which center core 8 and outer cores 9 are made from powder magnetic cores, but center core 18 and outer cores 19 can also be made from laminated cores made by laminating core material punched from electromagnetic steel sheets, as shown in perspective and side views in the configuration example of Figure 7. In this case, as shown as rotor 3C in support example 1, by supporting center core 18 and outer cores 19 with support members 10 in contact with each other, center core 18 and outer cores 19 can be supported without the core material coming apart.

[0041] Also, as shown in support example 2 as rotor 3D, by providing a support member 10 at one end and an end plate 30 at the other end in contact with the wall of the support member 10, the stacked state can be supported without coming apart. The shaft member 7 is press-fitted and fixed into the end plate 30.

[0042] Furthermore, when center core 18 and outer cores 19 are maintained in a laminated state by welding, crimping, or the like, two support members 10 can be positioned and supported so that they do not come into contact with each other, as shown as rotor 3E in support example 3. In this case, a predetermined range (R1) is formed in the axial direction where support members 10 are not present, and a gap exists inside rotor 3 in this range (R1), thereby improving the function as a flux barrier. Note that even when the laminated state can be maintained, support structures such as support example 1 and support example 2 can also be adopted.

[0043] Furthermore, as shown as rotor 3F in another configuration example 3 in FIG. 8 , magnets 40 may be provided on center core 8, outer core 9, or support member 10. For example, magnet 40a may be disposed inside inner wall portion 13a, magnet 40b may be disposed inside outer core 9a, or magnet 40c may be disposed so as to straddle inner wall portion 13b and outer core 9b. Although not shown, magnet 40 may also be disposed on center core 8. Such a configuration allows for a so-called self-starting reluctance motor. Note that the configuration shown in FIG. 8 is merely an example, and the number and arrangement of magnets 40 are not limited to this.

[0044] Up to this point, the explanation has focused mainly on the rotor 3, but a synchronous motor 1 equipped with the rotor 3 described above can also achieve the various effects described above, such as being able to reliably hold each iron core separated from each other while suppressing deterioration of the power factor.

[0045] In the embodiment, a so-called motor such as a synchronous reluctance motor or a self-starting reluctance motor is exemplified as the synchronous motor 1, but the present invention can also be applied to a generator also known as a reluctance machine.

[0046] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0047] In the drawings, 1 denotes a synchronous motor, 3, 3A to 3F denote rotors, 7 denotes a shaft member, 8, 18 denote central cores, 8a denotes a recess, 9, 9a to 9d, 19, 19a to 9d denote outer cores, 10 denotes a support member, 10b denotes a contact surface, 11 denotes a plate-shaped portion, 12 denotes an outer wall portion, 13, 13a to 13d denote inner wall portions, 20, 20a to 20c denote restricting portions, and 40, 40a to 40c denote magnets.

Claims

1. A shaft member; a central core having a core-side insertion hole at its center into which the shaft member is inserted, and a plurality of recesses recessed radially inward on its outer periphery; a plurality of outer cores disposed in the respective recesses at predetermined intervals between the outer core and the central core; a support member that supports the center core and the outer cores, The support member is a plate-shaped portion having a support-side insertion hole at its center into which the shaft member is inserted, and having contact surfaces that come into contact with the center core and the outer cores; an outer wall portion that rises in the axial direction from the plate-shaped portion and is provided at an outer edge of the outer core; an inner wall portion that rises axially from the plate-shaped portion and is positioned between the iron cores.

2. The support members are provided at both ends in the axial direction without contacting each other, 2. The rotor of a synchronous motor according to claim 1, wherein a space penetrating the interior of the rotor is formed between the center core and the outer core between the two support members.

3. a plurality of the outer cores are arranged in layers in the radial direction in one recess, 2. The rotor of a synchronous motor according to claim 1, wherein a plurality of said inner wall portions are provided in one recess, each of said inner wall portions being positioned between each of said iron cores.

4. 2. The rotor of a synchronous motor according to claim 1, wherein the outer core is formed in a shape having a portion wider than a portion exposed on the outer periphery.

5. 2. The rotor of a synchronous motor according to claim 1, further comprising a restricting portion provided on at least one of the inner wall portion and the outer wall portion for restricting misalignment of the outer core.

6. 2. The rotor of a synchronous motor according to claim 1, wherein the inner wall portion or the outer wall portion has an internal gap, or a plurality of the inner wall portion or the outer wall portion is disposed at intervals in the radial direction.

7. 2. The rotor of a synchronous motor according to claim 1, further comprising magnets provided on the center core, the outer core, or the support member.

8. A synchronous motor comprising the rotor according to any one of claims 1 to 7.

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