Rotor and electric motor

Abstract

This improves the manufacturability and performance of rotors manufactured by incorporating pre-magnetized magnets. [Solution] A rotor comprising: a plurality of rotor cores arranged radially; a plurality of magnets housed in a plurality of magnet housings formed by two adjacent rotor cores among the plurality of rotor cores; and a resin molded part integrally molded with the plurality of rotor cores and the plurality of magnets from resin, wherein at least one end face of the resin molded part has a plurality of openings, each of the plurality of openings includes an opening that overlaps at least a portion with only one of the plurality of magnet housings, and the geometric center of the opening is eccentric with respect to the centrifugal center line of the one magnet housing.

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a rotor and an electric motor.

Background Art

[0002] Patent Document 1 describes a brushless motor having a stator and a rotor rotatably disposed inside the stator. In this brushless motor, the rotor has magnets forming a plurality of poles accommodated in magnet accommodating portions formed radially. Further, the rotor has a synthetic resin cover portion provided at an axial end portion of the rotor. The cover portion communicates with the magnet accommodating portion and has a magnet introduction hole into which the magnet is inserted. The magnet introduction hole has a guide portion that abuts against the magnet and guides the magnet to a predetermined position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In some cases, a rotor is manufactured by incorporating a magnet that has been magnetized. In this case, due to the repulsive force or attractive force of the magnet, the manufacture of the rotor may become difficult. Further, since the position of the magnet is not stabilized due to the repulsive force or attractive force of the magnet, the performance of the rotor may deteriorate. That is, there is a risk that the manufacturability and performance of a rotor manufactured by incorporating a magnet that has been magnetized will decrease.

[0005] An object of the present invention is to improve the manufacturability and performance of a rotor manufactured by incorporating a magnet that has been magnetized.<00000To this end, the present invention provides a rotor comprising: a plurality of radially arranged rotor cores; a plurality of magnets housed in a plurality of magnet housings formed by two adjacent rotor cores among the plurality of rotor cores; and a resin molded part integrally molded with the plurality of rotor cores and the plurality of magnets from resin, wherein at least one end face of the resin molded part has a plurality of openings, each of the plurality of openings includes an opening that overlaps at least a portion with only one of the plurality of magnet housings, and the geometric center of the opening is eccentric with respect to the centrifugal center line of the one magnet housing.

[0007] The gap between the magnet housed in the first magnet housing and the two rotor cores forming the first magnet housing may be narrower on the side in which the geometric center of the opening is eccentric than on the side opposite to the direction in which the geometric center of the opening is eccentric.

[0008] The multiple openings may include at least one opening that overlaps at least partially with only two adjacent magnet storage compartments among the multiple magnet storage compartments. In this case, each of the at least one opening may include a first opening half the size of the opening that overlaps at least partially with one of the two magnet storage compartments, and a second opening half the size of the opening that overlaps at least partially with the other of the two magnet storage compartments.

[0009] Multiple openings may include only one opening in the centrifugal direction.

[0010] The multiple openings may include at least two openings in the centrifugal direction.

[0011] In that case, the direction in which the geometric centers of the openings included in at least two openings are eccentric may be the same. And in that case, the direction in which the geometric centers of the openings included in at least two openings are eccentric may be the same between two adjacent magnet housings among the multiple magnet housings and two pairs of at least two openings that overlap at least a portion of each other.

[0012] Furthermore, in that case, the directions in which the geometric centers of the openings included in at least two openings are eccentric may be different. And in that case, the directions in which the geometric centers of the openings included in at least two openings are eccentric may be different between two adjacent magnet housings among the multiple magnet housings and two sets of at least two openings that overlap at least a portion of each other.

[0013] The present invention also provides an electric motor comprising: a stator having a plurality of teeth protruding radially inward and windings wound around the plurality of teeth; a rotor having a plurality of rotor cores rotatably arranged inside the stator and arranged radially; a plurality of magnets housed in a plurality of magnet housings formed by two adjacent rotor cores among the plurality of rotor cores; and a resin molded part integrally molded with the plurality of rotor cores and the plurality of magnets from resin, wherein at least one end face of the resin molded part has a plurality of openings, each of the plurality of openings includes an opening that overlaps at least a portion with only one of the plurality of magnet housings, and the geometric center of the opening is eccentric with respect to the centrifugal center line of the one magnet housing. [Effects of the Invention]

[0014] According to the present invention, the manufacturability and performance of rotors manufactured by incorporating magnetized magnets can be improved. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing an example of the configuration of the electric motor in this embodiment. [Figure 2] This is a perspective view showing an example of the configuration of the rotor that constitutes the electric motor in this embodiment. [Figure 3A] This diagram shows the positioning of the magnets. [Figure 3B] This diagram shows the positioning of the magnets. [Figure 4] This figure shows the first step in the manufacturing process of the rotor in the first embodiment. [Figure 5]It is a diagram showing the second step of the manufacturing process of the rotor in the first embodiment. [Figure 6] It is a diagram showing the third step of the manufacturing process of the rotor in the first embodiment. [Figure 7] It is a diagram showing the fourth step of the manufacturing process of the rotor in the first embodiment. [Figure 8] It is a diagram showing the fifth step of the manufacturing process of the rotor in the first embodiment. [Figure 9] It is a perspective view showing a configuration example of the rotor in the first embodiment. [Figure 10] It is a bottom view showing a configuration example of the rotor in the first embodiment. [Figure 11] It is a perspective view showing a configuration example of the rotor in the second embodiment. [Figure 12] It is a bottom view showing a configuration example of the rotor in the second embodiment. [Figure 13] It is a perspective view showing a configuration example of the rotor in the third embodiment. [Figure 14] It is a bottom view showing a configuration example of the rotor in the third embodiment. [Figure 15] It is a perspective view showing a configuration example of the rotor in the fourth embodiment. [Figure 16] It is a bottom view showing a configuration example of the rotor in the fourth embodiment.

Embodiments for Carrying out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] [Electric Motor] FIG. 1 is a cross-sectional view showing a configuration example of the electric motor 1 in the present embodiment. As shown in Figure 1, the electric motor 1 comprises a rotor 10, a stator 20, and a shaft 30. The electric motor 1 further comprises a first bearing 41, a second bearing 42, a first metal plate 51, a second metal plate 52, a substrate 60, and a housing 70. The electric motor 1 is a brushless motor and is a spoke-type IPM (Interior Permanent Magnet) motor in which magnets 13 are radially embedded in the rotor 10.

[0018] The rotor 10 is positioned inside the stator 20, with an air gap between it and the stator 20. The rotor 10 rotates in the electric motor 1 and has a rotor hub 11, a rotor core 12, magnets 13, and a resin molded part 14. The rotor hub 11 is an annular member that is radially inward. There are multiple rotor cores 12, each of which is a radially outward member. There are also multiple magnets 13, each of which faces the stator 20 and is radially arranged between two adjacent rotor cores 12. Note that Figure 1 is a cross-sectional view of the electric motor 1 taken from the shaft 30 through the center of the rotor core 12 and outward in the radial direction, so the magnets 13 do not exist on this cross-sectional view. However, in Figure 1, the magnets 13 are also shown with dashed lines for illustrative purposes. The resin molded part 14 is a member integrally molded from resin together with the rotor hub 11, the multiple rotor cores 12, and the multiple magnets 13.

[0019] The stator 20 generates a rotating magnetic field, which rotates the rotor 10. The stator 20 has a back yoke 21, teeth 22, and windings 23. The back yoke 21 is an annular member on the radially outer side. There are multiple teeth 22, each of which protrudes radially inward. The windings 23 are wound around the teeth 22 via an insulator 24 to insulate the teeth 22. The stator 20 is molded from resin together with other fixed members. In this embodiment, the stator 20, which has a generally cylindrical outer shape, is constructed by integrally molding these members.

[0020] The shaft 30 is fixed to the rotor 10 and rotates together with the rotor 10. The shaft 30 rotates supported by a first bearing 41 and a second bearing 42. The shaft 30 protrudes from the first metal plate 51.

[0021] The first bearing 41 is positioned at the upper end of the shaft 30 and supports the shaft 30. The first bearing 41 is a cylindrical bearing having multiple balls. The second bearing 42 is located at the lower end of the shaft 30 and supports the shaft 30. The second bearing 42 is a cylindrical bearing having multiple balls.

[0022] The first metal plate 51 is a conductive member positioned at the upper end of the electric motor 1. The first metal plate 51 supports the first bearing 41, which is positioned in its central part. The second metal plate 52 is a conductive member located at the lower end of the electric motor 1. The second metal plate 52 supports the second bearing 42 located in its central part. The outer diameter of the second metal plate 52 is the same as or larger than the outer diameter of the first metal plate 51. This ensures that the first bearing 41 and the second bearing 42 are stably supported, allowing the shaft 30 to rotate.

[0023] The circuit board 60 is placed inside the electric motor 1 and has a drive circuit (not shown) mounted on it that outputs a drive signal to generate a rotating magnetic field on the winding 23. The circuit board 60 is placed between the rotor 10 and the stator 20 and the second metal sheet 52. For example, the drive circuit has an inverter circuit or the like mounted on it to apply voltage to the winding 23.

[0024] The housing 70, along with the first metal plate 51 and the second metal plate 52, houses the rotor 10, the stator 20, the first bearing 41, the second bearing 42, and the circuit board 60.

[0025] With the motor 1 configured as described above, applying voltage to the winding 23 from the drive circuit causes current to flow through the winding 23, generating a magnetic field from the teeth 22. Then, the rotating magnetic field from the teeth 22 and the magnetic field from the magnet 13 generate attractive and repulsive forces depending on the polarity of these magnetic fields. These forces cause the rotor 10 to rotate around the shaft 30.

[0026] Figure 2 is a perspective view showing an example of the configuration of the rotor 10 that constitutes the electric motor 1 in this embodiment. However, Figure 2 shows an example of the configuration with the resin molded part 14 removed. As shown in Figure 2, the rotor 10 has a rotor hub 11, a plurality of rotor cores 12, and a plurality of magnets 13. The rotor hub 11 and rotor cores 12 are made by laminating thin sheets of electromagnetic steel in the axial direction, and a portion of the rotor core 12 in the axial direction is connected to the rotor hub 11 by ribs. Each of the plurality of magnets 13 is housed in one of a plurality of magnet housings 19, which are composed of two adjacent rotor cores 12. Adjacent magnets 13 are arranged so that their opposing faces have the same magnetic poles. In this case, the magnetic poles of the rotor core 12 sandwiched between the adjacent magnets 13 have magnetic flux with the same poles as the magnetic poles of the opposing faces of the magnets 13. The magnetic flux of the magnetic poles of each rotor core 12 repels and attracts the magnetic field of the stator 20 (see Figure 1), causing the rotor 10 to rotate relative to the stator 20. Specifically, Figure 2 shows a 14-pole rotor 10, which has 14 rotor cores 12 and 14 magnets 13.

[0027] [Background and Overview] Incidentally, in spoke-type IPM motors, the effective magnetic flux can be significantly increased by increasing the number of poles. Also, in order to increase the effective magnetic force by reducing the magnetic flux leaking to the inner diameter side, many motors use a rotor core 12 that is not connected on the inner diameter side and is integrally molded in a resin molded part 14. Furthermore, to increase the magnetic force, it is conceivable to increase the number of poles, as shown in Figure 2 with 14 poles. However, when the number of poles is increased, the area of ​​the rotor core 12 between adjacent magnets 13 decreases. Therefore, in embedded magnetization, where unmagnetized magnets 13 are incorporated into the rotor core 12 and then magnetized, there is a problem that the magnetization is insufficient and the performance deteriorates.

[0028] Therefore, a method is being considered in which the magnets 13 are magnetized in advance and the magnetized magnets 13 are then incorporated into the rotor core 12. However, in spoke-type IPM motors, the magnets are arranged so that the same poles face each other, causing the magnetized magnets 13 to repel each other when they are assembled into the rotor core 12. This results in unstable positioning of the magnets 13, poor manufacturability, and also leads to increased noise and decreased efficiency due to variations in magnetic flux between the poles caused by the misalignment.

[0029] Therefore, in this embodiment, the position of the magnet 13 is stabilized by using magnetic force to determine its position, and magnetic flux variations due to misalignment are significantly suppressed. As a result, this embodiment aims to improve the manufacturability of the electric motor 1, reduce noise, and improve efficiency.

[0030] Figures 3A and 3B illustrate the positioning of the magnet 13. Specifically, Figures 3A and 3B are the same as Figure 2, but with the magnet support portion 85 added below the AA cross-sectional view.

[0031] In Figures 3A and 3B, magnets 13 are inserted into magnet housings 19 between adjacent rotor cores 12. A magnet support part 85, which is a mold component made of magnetic material, supports the magnets 13. This intentionally allows the magnetic flux B of the magnets 13 to pass through the magnet support part 85, generating an axial magnetic attractive force M1 and a circumferential magnetic attractive force M2.

[0032] In this case, the axial magnetic attractive force M1 is generated by passing the magnetic flux B through the magnet support portion 85. Furthermore, if only this magnetic attractive force M1 is to be generated, it is unnecessary to eccentrically position the geometric center W of the magnet support portion 85 relative to the center Cs of the magnet housing portion 19. However, it is necessary to design the area of ​​the magnet support portion 85 such that the axial magnetic attractive force M1 is far greater than the repulsive force of the magnet 13.

[0033] Furthermore, the circumferential magnetic attraction force M2 is generated by offsetting the geometric center W of the magnet support portion 85 with respect to the center Cs of the magnet housing portion 19. The magnetic attraction force M2 is generated in the eccentric direction where the geometric center W of the magnet support portion 85 is eccentric.

[0034] In Figure 3A, the center Cm of the magnet 13 coincides with the center Cs of the magnet housing 19. In contrast, in Figure 3B, due to the eccentric magnetic attraction force M2, the center Cm of the magnet 13 is offset from the center Cs of the magnet housing 19. The magnet 13 is then positioned to contact the rotor core 12.

[0035] In this embodiment, this configuration allows the position of the magnet 13 to be stabilized within the molding die without the need to add any special parts, thus facilitating manufacturing. Furthermore, in this embodiment, the magnet support portion 85 is separated from the rotor 10 after molding. Therefore, there is no effect of reduced magnetic force due to leakage flux. Furthermore, in this embodiment, since all the magnets 13 housed within the rotor 10 can be positioned, it is possible to suppress imbalances in the magnetic flux of the rotor 10's magnetic pole surfaces. This improves the performance of the electric motor 1 and reduces noise.

[0036] [First Embodiment] The first embodiment is an example in which a single magnet 13 is supported by a plurality of magnet support parts 85, the magnet support parts 85 connect adjacent magnets 13, and the magnet 13 is eccentric in different directions on the inner circumference side and the outer circumference side. Specifically, a magnetic plate-shaped magnet support section 85, connecting adjacent magnet storage sections 19, supports the magnet 13 within the injection molding die 80 (described later). The magnet support section 85 is positioned such that the geometric centers of the portions divided equally in the circumferential direction are eccentric with respect to the centrifugal (magnetic pole direction) centerline of the magnet storage section 19. In this state, the magnetized magnet 13 is fixed within the injection molding die 80 (described later). As a result, the axial magnetic attraction prevents the magnet 13 from flying out, and the eccentric magnetic attraction positions it in the circumferential direction.

[0037] Here, the manufacturing process of the rotor 101 in the first embodiment will be described. Figures 4 to 8 show the manufacturing process of the rotor 10 in the first embodiment.

[0038] In the first step, a lower mold 82 is prepared as shown in Figure 4. The lower mold 82 has a base portion 84, a magnet support portion 85, a rotor hub pin 86, and a rotor core pin 87. The base portion 84 is placed on the mounting surface and is the part on which the upper mold 81 (described later) is placed. The magnet support portion 85 has the function described in Figures 3A and 3B. In the first embodiment, the magnet support portion 85 is formed in a direction that connects adjacent magnets 13. In particular, in the second step, the magnet support portion 85 is formed such that the geometric center of half of it is eccentric in different directions on the inner and outer sides with respect to the centrifugal center line of the magnet housing portion 19. The rotor hub pin 86 is a pin for fixing the rotor hub 11. The rotor core pin 87 is a pin for determining the phase of the rotor 10 by fixing each rotor core 12.

[0039] In the second step, as shown in Figure 5, the rotor hub 11 and rotor core 12 are set in the lower mold 82. Specifically, the rotor hub 11 is fixed to the lower mold 82 by inserting the rotor hub pin 86 into the hollow central part of the rotor hub 11. In addition, the rotor core 12 is fixed to the lower mold 82 by inserting the rotor core pin 87 (not visible in the figure) into the recess on the lower surface of the rotor core 12 (not visible in the figure).

[0040] In the third step, as shown in Figure 6, the magnet 13 is inserted into the magnet housing 19 between the rotor cores 12. At this time, the magnet 13 is positioned and fixed by magnetic force due to the effect of the magnet support part 85 (not visible in the figure).

[0041] In the fourth step, as shown in Figure 7, the mold is closed by lowering the upper mold 81 relative to the lower mold 82. As a result, the upper mold 81 and the lower mold 82 constitute the injection molding die 80. Then, resin is injected into the injection molding die 80 and solidified by injection molding.

[0042] In the fifth step, as shown in Figure 8, the mold is opened by raising the upper mold 81 relative to the lower mold 82. Then, the rotor 101, which is the manufactured product produced in this manufacturing process, is removed. The rotor 101 has a rotor hub 11, a rotor core 12, and a resin molded part 141 which is integrally molded with a magnet 13 (not visible in the figure) in resin.

[0043] Figure 9 is a perspective view showing an example of the configuration of the rotor 101 in the first embodiment. However, in Figure 9, the rotor 101 removed in the fifth step shown in Figure 8 is shown upside down to illustrate the configuration example. In the rotor 101 manufactured using the manufacturing process shown in Figures 4 to 8, a plurality of magnet openings 151 are formed on the lower surface of the resin molded portion 141, as shown in Figure 9. The plurality of magnet openings 151 are openings that allow a portion of the magnet 13 to be viewed. The plurality of magnet openings 151 is just one example of a plurality of openings. In addition, a rotor hub opening 161 and a rotor core opening 171 are also formed in the resin molded portion 141. The rotor hub opening 161 is the opening into which the rotor hub pin 86 was inserted, and into which the shaft 30 is inserted. The rotor core opening 171 is the opening into which the rotor core pin 87 was inserted.

[0044] Figure 10 is a bottom view showing an example of the configuration of the rotor 101 in the first embodiment. As shown in Figure 10, the resin molded section 141 contains magnet housings 19a, 19b, magnets 13a, 13b, etc. In addition, the resin molded section 141 has magnet openings 151a to 151c, a rotor core opening 171, etc.

[0045] For example, the geometric center W12a of the lower half of the magnet opening 151a is eccentric in the clockwise direction E12a with respect to the centrifugal center line Csa of the magnet housing 19a. As a result, the outer circumference of the magnet 13a is positioned eccentrically in the direction E12a. In this case, the gap between the magnet 13a and the two rotor cores 12 is narrower on the side facing the eccentric direction E12a than on the side opposite to the eccentric direction E12a. Furthermore, the lower half of the magnet opening 151a is an opening that overlaps with at least a portion of only one magnet housing 19a.

[0046] Furthermore, for example, the geometric center W11b of the upper half of the magnet opening 151b is eccentric in the counterclockwise eccentric direction E11b with respect to the centrifugal center line Csa of the magnet housing 19a. As a result, the inner circumference side of the magnet 13a is positioned eccentrically in the eccentric direction E11b. In this case, the gap between the magnet 13a and the two rotor cores 12 is narrower on the side in the eccentric direction E11b than on the side opposite to the eccentric direction E11b. Also, the upper half of the magnet opening 151b is an opening that overlaps with at least a portion of only one magnet housing 19a. Furthermore, the magnet opening 151b is an example of an opening that overlaps with at least a portion of only two adjacent magnet housings. The upper half of the magnet opening 151b is an example of a first opening that overlaps with at least a portion of one of two magnet housings.

[0047] Furthermore, for example, the geometric center W12b of the lower half of the magnet opening 151b is eccentric in the clockwise eccentric direction E12b with respect to the centrifugal center line Csb of the magnet housing 19b. As a result, the inner circumference side of the magnet 13b is positioned eccentrically in the eccentric direction E12b. In this case, the gap between the magnet 13b and the two rotor cores 12 is narrower on the side in the eccentric direction E12b than on the side opposite to the eccentric direction E12b. Also, the lower half of the magnet opening 151b is an opening that overlaps with at least a portion of only one magnet housing 19b. Furthermore, the magnet opening 151b is an example of an opening that overlaps with at least a portion of only two adjacent magnet housings. The lower half of the magnet opening 151b is an example of a second opening that overlaps with at least a portion of the other of two magnet housings.

[0048] Furthermore, for example, the geometric center W11c of the upper half of the magnet opening 151c is eccentric in the counterclockwise direction E11c with respect to the centrifugal center line Csb of the magnet housing 19b. As a result, the outer circumference of the magnet 13b is positioned eccentrically in the eccentric direction E11c. In this case, the gap between the magnet 13b and the two rotor cores 12 is narrower on the side in the eccentric direction E11c than on the side opposite to the eccentric direction E11c. Also, the upper half of the magnet opening 151c is an opening that overlaps with at least a portion of only one magnet housing 19b.

[0049] With this configuration, the area of ​​the region including the rotor core 12 between adjacent magnets 13 becomes approximately the same for all adjacent magnets 13. As a result, it becomes possible to suppress the imbalance of magnetic flux on the magnetic pole surfaces of the rotor core 12.

[0050] In the first embodiment, the manufacturability and performance of the electric motor 1, which is manufactured by incorporating the magnetized magnet 13 into the rotor core 12, can be improved. Furthermore, in the first embodiment, the number of parts can be reduced by using a plate-shaped magnet support part 85. Furthermore, in the first embodiment, it became possible to secure a gap between the magnet opening 151 and the rotor core opening 171. As a result, it became possible to simplify the manufacturing of the rotor 10 and suppress a decrease in the strength of the rotor 10.

[0051] [Second Embodiment] The second embodiment is an example in which one magnet 13 is supported by one magnet support part 85, and all magnets 13 are eccentric in the same direction in the circumferential direction. Specifically, a magnetic plate-shaped magnet support portion 85 is placed in the injection molding die 80 such that its geometric center is eccentric with respect to the centrifugal (magnetic pole direction) centerline of the magnet housing portion 19. In this state, the magnetized magnet 13 is fixed inside the injection molding die 80. Then, the magnetic force of the magnet support portion 85 generates a magnetic attraction force between the magnet 13 and the magnet support portion 85. As a result, the axial magnetic attraction force prevents the magnet 13 from flying out, and the eccentric magnetic attraction force positions it in the circumferential direction.

[0052] In the second embodiment, the rotor 102 is manufactured using the same manufacturing process as shown in Figures 4 to 8. However, in the second embodiment, in the first step shown in Figure 4, a lower mold 82 is prepared in which a plate-shaped magnet support portion 85 is formed in the centrifugal direction. In particular, in the lower mold 82, the magnet support portion 85 is formed such that in the second step, its geometric center is eccentric in the same circumferential direction with respect to the centrifugal center line of the magnet housing portion 19. Also in the second embodiment, in the fifth step shown in Figure 8, the rotor 102 having the resin molded portion 142 is removed.

[0053] Figure 11 is a perspective view showing an example of the configuration of the rotor 102 in the second embodiment. However, in Figure 11, the rotor 102, which was removed in the fifth step similar to that shown in Figure 8, is shown upside down as an example of its configuration. In a rotor 102 manufactured using the same manufacturing process as shown in Figures 4 to 8, a plurality of magnet openings 152 are formed on the lower surface of the resin molded portion 142, as shown in Figure 11. The plurality of magnet openings 152 are openings that allow a portion of the magnet 13 to be viewed. The plurality of magnet openings 152 is just one example of multiple openings. Only one magnet opening 152 is formed in the centrifugal direction. In addition, a rotor hub opening 162 and a rotor core opening 172 are also formed in the resin molded portion 142. The rotor hub opening 162 is the opening into which the rotor hub pin 86 was inserted, and into which the shaft 30 is inserted. The rotor core opening 172 is the opening into which the rotor core pin 87 was inserted.

[0054] Figure 12 is a bottom view showing an example of the configuration of the rotor 102 in the second embodiment. As shown in Figure 12, the resin molded section 142 contains magnet housings 19a, 19b, magnets 13a, 13b, etc. In addition, magnet openings 152a, 152b, etc. are formed in the resin molded section 142.

[0055] For example, the geometric center W2a of the magnet opening 152a is eccentric in the counterclockwise direction E2a with respect to the centrifugal center line Csa of the magnet housing 19a. As a result, the magnet 13a is positioned eccentrically in the eccentric direction E2a. In this case, the gap between the magnet 13a and the two rotor cores 12 is narrower on the side facing the eccentric direction E2a than on the side facing the opposite eccentric direction E2a. Furthermore, the magnet opening 152a is an opening that overlaps with at least a portion of only one magnet housing 19a.

[0056] Furthermore, for example, the geometric center W2b of the magnet opening 152b is eccentric in the counterclockwise eccentric direction E2b with respect to the centrifugal center line Csb of the magnet housing 19b. As a result, the magnet 13b is positioned eccentrically in the eccentric direction E2b. In this case, the gap between the magnet 13b and the two rotor cores 12 is narrower on the side in the eccentric direction E2b than on the side opposite to the eccentric direction E2b. Also, the magnet opening 152b is an opening that overlaps with at least a portion of only one magnet housing 19b.

[0057] With this configuration, the area of ​​the region including the rotor core 12 between adjacent magnets 13 becomes approximately the same for all adjacent magnets 13. As a result, it becomes possible to suppress the imbalance of magnetic flux on the magnetic pole surfaces of the rotor core 12.

[0058] In addition, the above example shows all magnets 13 eccentrically positioned in the same direction circumferentially, but some magnets 13 may be eccentrically positioned in different directions circumferentially from other magnets 13. In particular, adjacent magnets 13 may be eccentrically positioned in opposite directions.

[0059] In the second embodiment, the manufacturability and performance of the electric motor 1, which is manufactured by incorporating the magnetized magnet 13 into the rotor core 12, can be improved. Furthermore, in the second embodiment, the number of parts can be reduced by using a plate-shaped magnet support part 85.

[0060] [Third Embodiment] The third embodiment is an example in which one magnet 13 is supported by multiple magnet support parts 85, and all magnets 13 are eccentric in the same direction in the circumferential direction. Specifically, a pin-shaped magnetic support portion 85 is placed in the injection molding die 80 such that its geometric center is eccentric with respect to the centrifugal (magnetic pole direction) centerline of the magnet housing portion 19. In this state, the magnetized magnet 13 is fixed to the injection molding die 80. Then, the magnetic force of the magnet support portion 85 generates a magnetic attraction force between the magnet 13 and the magnet support portion 85. As a result, the axial magnetic attraction force prevents the magnet 13 from flying out, and the eccentric magnetic attraction force positions it in the circumferential direction.

[0061] In the third embodiment, the rotor 103 is manufactured using the same manufacturing process as shown in Figures 4 to 8. However, in the third embodiment, in the first step shown in Figure 4, a lower mold 82 is prepared in which two pin-shaped magnet support portions 85 are formed in the centrifugal direction. In particular, in the lower mold 82, the magnet support portions 85 are formed in the second step such that their geometric centers are eccentric in the same circumferential direction with respect to the centrifugal center line of the magnet housing portion 19. Also, in the third embodiment, in the fifth step shown in Figure 8, the rotor 103 having the resin molded portion 143 is removed.

[0062] Figure 13 is a perspective view showing an example of the configuration of the rotor 103 in the third embodiment. However, in Figure 13, the configuration example is shown with the rotor 103, which was removed in the fifth step similar to that shown in Figure 8, inverted. In a rotor 103 manufactured using the same manufacturing process as shown in Figures 4 to 8, a plurality of magnet openings 153 are formed on the lower surface of the resin molded portion 143, as shown in Figure 13. The plurality of magnet openings 153 are openings that allow a part of the magnet 13 to be viewed. The plurality of magnet openings 153 is just one example of a plurality of openings. Two magnet openings 153 are formed in the centrifugal direction. However, two or more magnet openings 153 may be formed in the centrifugal direction. In addition, a rotor hub opening 163 and a rotor core opening 173 are also formed in the resin molded portion 143. The rotor hub opening 163 is the opening into which the rotor hub pin 86 was inserted, and into which the shaft 30 is inserted. The rotor core opening 173 is the opening into which the rotor core pin 87 was inserted.

[0063] Figure 14 is a bottom view showing an example of the configuration of the rotor 103 in the third embodiment. As shown in Figure 14, the resin molded section 143 contains magnet housings 19a, 19b, magnets 13a, 13b, etc. In addition, magnet openings 153a to 153d, etc. are formed in the resin molded section 143.

[0064] For example, the geometric center W3a of the magnet opening 153a is eccentric in the counterclockwise direction E3a with respect to the centrifugal center line Csa of the magnet housing 19a. The geometric center W3c of the magnet opening 153c is eccentric in the counterclockwise direction E3c with respect to the centrifugal center line Csa of the magnet housing 19a. As a result, the magnet 13a is positioned eccentrically in the eccentric directions E3a and E3c. In this case, the gap between the magnet 13a and the two rotor cores 12 is narrower on the side of the eccentric directions E3a and E3c than on the side opposite to the eccentric directions E3a and E3c. In addition, each of the magnet openings 153a and 153c overlaps with at least a portion of only one magnet housing 19a.

[0065] Furthermore, for example, the geometric center W3b of the magnet opening 153b is eccentric in the counterclockwise direction E3b with respect to the centrifugal center line Csb of the magnet housing 19b. The geometric center W3d of the magnet opening 153d is eccentric in the counterclockwise direction E3d with respect to the centrifugal center line Csb of the magnet housing 19b. As a result, the magnet 13b is positioned eccentrically in the eccentric directions E3b and E3d. In this case, the gap between the magnet 13b and the two rotor cores 12 is narrower on the side of the eccentric directions E3b and E3d than on the side opposite to the eccentric directions E3b and E3d. Also, each of the magnet openings 153b and 153d overlaps with at least a portion of only one magnet housing 19b.

[0066] With this configuration, the area of ​​the region including the rotor core 12 between adjacent magnets 13 becomes approximately the same for all adjacent magnets 13. As a result, it becomes possible to suppress the imbalance of magnetic flux on the magnetic pole surfaces of the rotor core 12.

[0067] In addition, the above example shows all magnets 13 eccentrically positioned in the same direction circumferentially, but some magnets 13 may be eccentrically positioned in different directions circumferentially from other magnets 13. In particular, adjacent magnets 13 may be eccentrically positioned in opposite directions.

[0068] In the third embodiment, the manufacturability and performance of the electric motor 1, which is manufactured by incorporating the magnetized magnet 13 into the rotor core 12, can be improved. Furthermore, in the third embodiment, the use of a pin-shaped magnet support portion 85 facilitates the manufacturing of mold components. Furthermore, in the third embodiment, by supporting a single magnet 13 with multiple magnet support parts 85, it becomes possible to stably hold the magnet 13.

[0069] [Fourth Embodiment] The fourth embodiment is an example in which a single magnet 13 is supported by a plurality of magnet support parts 85, and the magnet 13 is eccentric in different directions on the inner circumference side and the outer circumference side. Specifically, a pin-shaped magnetic support portion 85 is placed in the injection molding die 80 such that its geometric center is eccentric with respect to the centrifugal (magnetic pole direction) centerline of the magnet housing portion 19. In this state, the magnetized magnet 13 is fixed to the injection molding die 80. Then, the magnetic force of the magnet support portion 85 generates a magnetic attraction force between the magnet 13 and the magnet support portion 85. As a result, the axial magnetic attraction force prevents the magnet 13 from flying out, and the eccentric magnetic attraction force positions it in the circumferential direction.

[0070] In the fourth embodiment, the rotor 104 is manufactured using the same manufacturing process as shown in Figures 4 to 8. However, in the fourth embodiment, in the first step shown in Figure 4, a lower mold 82 is prepared in which two pin-shaped magnet support portions 85 are formed in the centrifugal direction. In particular, in the lower mold 82, the magnet support portions 85 are formed such that in the second step, their geometric centers are eccentric in different directions on the inner and outer sides relative to the centrifugal centerline of the magnet housing portion 19. Also in the fourth embodiment, in the fifth step shown in Figure 8, the rotor 104 having the resin molded portion 144 is removed.

[0071] Figure 15 is a perspective view showing an example of the configuration of the rotor 104 in the fourth embodiment. However, in Figure 15, the rotor 104, which was removed in the fifth step similar to that shown in Figure 8, is shown upside down as an example of its configuration. In a rotor 104 manufactured using the same manufacturing process as shown in Figures 4 to 8, a plurality of magnet openings 154 are formed on the lower surface of the resin molded portion 144, as shown in Figure 15. The plurality of magnet openings 154 are openings that allow a portion of the magnet 13 to be viewed. The plurality of magnet openings 154 is just one example of a plurality of openings. Two magnet openings 154 are formed in the centrifugal direction. However, two or more magnet openings 154 may be formed in the centrifugal direction. In addition, a rotor hub opening 164 and a rotor core opening 174 are also formed in the resin molded portion 144. The rotor hub opening 164 is the opening into which the rotor hub pin 86 was inserted, and into which the shaft 30 is inserted. The rotor core opening 174 is the opening into which the rotor core pin 87 was inserted.

[0072] Figure 16 is a bottom view showing an example of the configuration of the rotor 104 in the fourth embodiment. As shown in Figure 16, the resin molded section 144 contains magnet housings 19a, 19b, magnets 13a, 13b, etc. In addition, magnet openings 154a to 154d, etc. are formed in the resin molded section 144.

[0073] For example, the geometric center W4a of the magnet opening 154a is eccentric in a clockwise direction E4a with respect to the centrifugal center line Csa of the magnet housing 19a. The geometric center W4c of the magnet opening 154c is eccentric in a counterclockwise direction E4c with respect to the centrifugal center line Csa of the magnet housing 19a. As a result, the outer circumference of the magnet 13a is eccentrically positioned in the direction E4a, and the inner circumference of the magnet 13a is eccentrically positioned in the direction E4c. In this case, the gap between the magnet 13a and the two rotor cores 12 is narrower on the outer circumference side on the side of eccentricity E4a than on the side opposite to eccentricity E4a. The gap between the magnet 13a and the two rotor cores 12 is narrower on the inner circumference side on the side of eccentricity E4c than on the side opposite to eccentricity E4c. Furthermore, each of the magnet openings 154a and 154c is an opening that overlaps with at least a portion of only one magnet storage section 19a.

[0074] Furthermore, for example, the geometric center W4b of the magnet opening 154b is eccentric in the counterclockwise direction E4b with respect to the centrifugal center line Csb of the magnet housing 19b. The geometric center W4d of the magnet opening 154d is eccentric in the clockwise direction E4d with respect to the centrifugal center line Csb of the magnet housing 19b. As a result, the outer circumference of the magnet 13b is eccentrically positioned in the eccentric direction E4b, and the inner circumference of the magnet 13b is eccentrically positioned in the eccentric direction E4d. In this case, the gap between the magnet 13b and the two rotor cores 12 is narrower on the outer circumference side on the side of eccentric direction E4b than on the side opposite to eccentric direction E4b. The gap between the magnet 13b and the two rotor cores 12 is narrower on the inner circumference side on the side of eccentric direction E4d than on the side opposite to eccentric direction E4d. Furthermore, each of the magnet openings 154b and 154d is an opening that overlaps with at least a portion of only one magnet storage section 19b.

[0075] With this configuration, the area of ​​the region including the rotor core 12 between adjacent magnets 13 becomes approximately the same for all adjacent magnets 13. As a result, it becomes possible to suppress the imbalance of magnetic flux on the magnetic pole surfaces of the rotor core 12.

[0076] In addition, although the above example shows all magnets 13 being eccentric in different directions in the circumferential direction, some magnets 13 may be eccentric in the same direction in the circumferential direction as the other magnets 13. In particular, adjacent magnets 13 may be eccentric in the same direction.

[0077] In the fourth embodiment, the manufacturability and performance of the electric motor 1, which is manufactured by incorporating the magnetized magnet 13 into the rotor core 12, can be improved. Furthermore, in the fourth embodiment, the use of a pin-shaped magnet support portion 85 facilitates the manufacturing of mold components. Furthermore, in the fourth embodiment, by supporting a single magnet 13 with multiple magnet support parts 85, it becomes possible to stably hold the magnet 13.

[0078] [Differentiation] In the first to fourth embodiments, the shape of the magnet opening 15 was substantially rectangular or circular. However, the shape of the magnet opening 15 may be other shapes.

[0079] Furthermore, in the first to fourth embodiments, the magnet support portion 85 supports the magnet 13 from the lower surface of the resin molded portion 14, and a magnet opening 15 is formed on the lower surface of the resin molded portion 14. However, instead of this, or in addition to this, the magnet support portion 85 may support the magnet 13 from the upper surface of the resin molded portion 14, and a magnet opening 15 may be formed on the upper surface of the resin molded portion 14. In other words, the magnet opening 15 may be formed on at least one end face of the resin molded portion 14. [Explanation of Symbols]

[0080] 1…Electric motor, 10, 101, 102, 103, 104…Rotor, 11…Rotor hub, 12…Rotor core, 13…Magnet, 14…Resin molded part, 151, 152, 153, 154…Magnet opening, 19…Magnet housing, 20…Stator, 21…Back yoke, 22…Teeth, 23…Winding, 30…Shaft, 41…First bearing, 42…Second bearing, 51…First metal plate, 52…Second metal plate, 60…Substrate, 70…Housing, 80…Injection molding die, 81…Upper mold, 82…Lower mold, 85…Magnet support part

Claims

1. Multiple rotor cores arranged radially, Multiple magnets housed in multiple magnet housings formed by two adjacent rotor cores among the aforementioned multiple rotor cores, A resin molded portion integrally molded with the plurality of rotor cores and the plurality of magnets, It has, At least one end face of the resin molded portion is provided with a plurality of openings, A rotor in which each of the plurality of openings includes an opening that overlaps at least a portion with only one of the plurality of magnet housings, and the geometric center of the opening is eccentric with respect to the centrifugal center line of the one magnet housing.

2. The rotor according to claim 1, wherein the gap between the magnet housed in the first magnet housing and the two rotor cores forming the first magnet housing is narrower on the side in the direction in which the geometric center of the opening is eccentric than on the side opposite to the direction in which the geometric center of the opening is eccentric.

3. The rotor according to claim 1, wherein the plurality of openings include at least one opening that overlaps at least a portion with only two adjacent magnet housings among the plurality of magnet housings.

4. The rotor according to claim 3, wherein each of the at least one openings includes a first opening half the size of the opening and overlapping at least a portion with one of the two magnet housings, and a second opening half the size of the opening and overlapping at least a portion with the other of the two magnet housings.

5. The rotor according to claim 1, wherein the plurality of openings include only one opening in the centrifugal direction.

6. The rotor according to claim 1, wherein the plurality of openings include at least two openings in the centrifugal direction.

7. The rotor according to claim 6, wherein the direction in which the geometric centers of the openings included in the at least two openings are eccentric is the same.

8. The rotor according to claim 7, wherein the direction in which the geometric centers of the openings included in the at least two openings are eccentric is the same between two sets of the at least two openings that overlap at least a portion with two adjacent magnet housings among the plurality of magnet housings.

9. The rotor according to claim 6, wherein the directions in which the geometric centers of the openings included in the at least two openings are eccentric are different.

10. The rotor according to claim 9, wherein the direction in which the geometric centers of the openings included in the at least two openings are eccentric differs between two sets of the at least two openings that overlap at least a portion with two adjacent magnet housings among the plurality of magnet housings.

11. A stator having a plurality of teeth protruding radially inward, and a winding wound around the plurality of teeth, A rotor having a plurality of rotor cores rotatably arranged radially inside the stator, a plurality of magnets housed in a plurality of magnet housings formed by two adjacent rotor cores, and a resin molded part integrally molded with the plurality of rotor cores and the plurality of magnets from resin, Equipped with, At least one end face of the resin molded portion is provided with a plurality of openings, An electric motor in which each of the plurality of openings includes an opening that overlaps at least a portion with only one of the plurality of magnet housings, and the geometric center of the opening is eccentric with respect to the centrifugal center line of the one magnet housing.

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