Rotary electric machine

Abstract

A motor (101) comprises: an inner core (104) and an outer core (108) that are formed so as to be rotatable relative to each other about a common rotary shaft (106); a plurality of magnets (105) that are provided to the inner core (104); and a plurality of windings (109) that are wound around the outer core (108). The outer core (108) comprises a plurality of magnetic body blocks (120) that are arranged in the circumferential direction with respect to the rotary shaft (106) and connected to each other. Each of the magnetic body blocks (120) comprises a base part 131 connected to an adjacent magnetic body block (120), and a protrusion (132) protruding from the base part 131 toward the inner core (104). Each of the plurality of windings (109) is wound around the protrusion (132) in one of the plurality of magnetic body blocks (120). Each of the magnetic body blocks (120) comprises a plurality of magnetic body components (121-123) each constituting a portion of the protrusion (132), which is divided in the circumferential direction.

Description

rotating electrical machines

[0001] The present disclosure relates to a rotating electric machine.

[0002] For reasons of cost and ease of winding, thin conductor wires with a circular cross section (round wires) are often used as windings for rotating electrical machines such as motors or generators. However, rectangular wires with a rectangular cross section are sometimes used instead of round wires for rotating electrical machines. Compared to round wires, rectangular wires improve the winding space factor (i.e., the ratio of the conductor to the winding area) in the cross section, reduce winding resistance, reduce copper loss, and further increase the current value for the same copper loss, thereby improving torque and ultimately enabling the miniaturization of rotating electrical machines.

[0003] A rectangular wire is less likely to deform than a round wire, and therefore it is difficult to wind a rectangular wire around a magnetic core of a rotating electrical machine. For this reason, when a rectangular wire is used as a winding for a rotating electrical machine, the winding is pre-formed into a coil shape and attached to the magnetic core. To make it easier to attach the pre-formed coil shape to the magnetic core, the magnetic core is sometimes divided into multiple magnetic parts.

[0004] For example, Patent Document 1 discloses a motor stator in which the flange portion of the stator core is molded separately from the other parts, and multiple flange portions are arranged and fixed in a ring shape along the circumferential direction of the motor by a predetermined fixing means.

[0005] Japanese Patent Application Laid-Open No. 2006-296037

[0006] When a magnetic core is divided into multiple magnetic components, the magnetic flux becomes difficult to flow due to gaps and adhesives at the joints (joint surfaces) between the divided magnetic components. Therefore, a magnetic core made up of multiple magnetic components may have lower performance, such as torque, than a magnetic core made up of an integrated magnetic component. For this reason, it is necessary to make it difficult for torque to decrease, even when the magnetic core is made up of multiple magnetic components.

[0007] An object of the present disclosure is to provide a rotating electric machine that includes a magnetic core made up of a plurality of magnetic components and that achieves improved torque compared to conventional rotating electric machines.

[0008] A rotating electric machine according to one aspect of the present disclosure comprises: first and second magnetic cores formed to be rotatable relative to each other around a common rotation axis; a plurality of magnets provided in the first magnetic core; and a plurality of windings wound around the second magnetic core; the second magnetic core comprises a plurality of magnetic blocks arranged circumferentially about the rotation axis and connected to each other; each of the plurality of magnetic blocks comprises a base connected to an adjacent magnetic block and a protrusion protruding from the base toward the first magnetic core; each of the plurality of windings is wound around the protrusion of one of the plurality of magnetic blocks; and each of the plurality of magnetic blocks comprises a plurality of magnetic components each including a portion of the protrusion divided in the circumferential direction.

[0009] According to one aspect of the present disclosure, it is possible to provide a rotating electric machine including a magnetic core made up of a plurality of magnetic components, which realizes improved torque compared to conventional rotating electric machines.

[0010] 2. A longitudinal sectional view showing an example of the configuration of the motor 101 according to the first embodiment. A transverse sectional view showing an example of the configuration of the motor 101 according to the first embodiment. A perspective view showing one magnetic body block 120 and one winding 109 of the stator 103 of FIG. 2. A transverse sectional view showing one magnetic body block 120 and one winding 109 of the stator 103 of FIG. 2. A top view showing a first step of assembling one magnetic body block 120 of the stator 103 of FIG. 2. A top view showing a second step of assembling one magnetic body block 120 of the stator 103 of FIG. 2. A top view showing a third step of assembling one magnetic body block 120 of the stator 103 of FIG. 2. A top view showing a fourth step of assembling one magnetic body block 120 of the stator 103 of FIG. 2. A transverse sectional view showing a magnetic body block 140 and a winding 109 according to a first comparative example. A transverse sectional view showing a magnetic body block 150 and a winding 109 according to a second comparative example. 1 is a graph showing the rate of change in torque when the gap between the joining surfaces of the magnetic body components is changed for the magnetic body block 120 according to the example, the magnetic body block 140 according to the first comparative example, and the magnetic body block 150 according to the second comparative example.

[0033] FIG. 1 is a graph showing the rate of change in torque when the width of the magnetic body component 121 is changed and the gap between the joining surfaces of the magnetic body components 121 to 123 is changed for the magnetic body block 120 according to the example.

[0034] FIG. 1 is a perspective view showing a magnetic body block 120A and one winding 109 according to a first modified example of the first embodiment.

[0035] FIG. 2 is a side view showing a magnetic body block 120B according to a second modified example of the first embodiment.

[0036] FIG. 3 is a cross-sectional view showing a magnetic body block 120D and one winding 109 according to the second embodiment.

[0037] FIG. 4 is a graph showing the rate of change in torque when the width of the magnetic body component 121D is changed and the gap between the joining surfaces of the magnetic body components 121D to 123D is changed for the magnetic body block 120D according to the example. 15 is a cross-sectional view showing a magnetic block 120E and one winding 109E according to a third embodiment. FIG. 16 is a top view for explaining the assembly of the magnetic block 120E of FIG.

[0011] Hereinafter, a rotating electric machine according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the configuration described below is merely an example of the present disclosure, and the present disclosure is not limited to the following embodiment. Even if it is not an embodiment, various modifications can be made depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure.

[0012] [First embodiment] [Motor configuration] Fig. 1 is a longitudinal sectional view showing an example of the configuration of a motor 101 according to an embodiment. Fig. 2 is a transverse sectional view showing an example of the configuration of a motor 101 according to an embodiment. In this embodiment, a motor having an inner rotor configuration with a rotor inside a stator, a magnet on the rotor, and a winding on the stator will be described.

[0013] The motor 101 includes a rotor 102, a stator 103, a pair of bearings 107, and a housing 110. The stator 103 and the bearings 107 are fixed to the housing 110. The rotor 102 is rotatably supported by the pair of bearings 107 inside the stator 103.

[0014] In FIG. 2, the housing 110 is omitted for simplicity of illustration.

[0015] In this specification, the direction in which the rotation axis 106 extends (the Z direction in Figure 1, etc.) is referred to as the direction of the rotation axis 106 or the axial direction, and in a plane perpendicular to this axial direction (the XY plane in Figure 2, etc.), the direction spreading from the center of the rotation axis 106 is referred to as the radial direction, and the direction going around the center is referred to as the circumferential direction.

[0016] The rotor 102 includes an inner core 104, a plurality of magnets 105, and a rotating shaft 106. The inner core 104 is a magnetic core having a substantially cylindrical shape. The rotating shaft 106 passes through the inner core 104, and the inner core 104 is mechanically coupled to the rotating shaft 106. The rotating shaft 106 is supported by a pair of bearings 107, and the rotor 102 rotates around the rotating shaft 106. The plurality of magnets 105 are permanent magnets provided at equal intervals along the outer periphery of the inner core 104. In the example of FIG. 2 , ten magnets 105 are provided. For example, each magnet 105 has a rectangular parallelepiped shape, and the inner core 104 has a plurality of substantially rectangular holes formed at equal intervals along its outer periphery, and a magnet 105 is inserted into each hole. Each magnet 105 becomes a magnetic pole of the rotor 102.

[0017] The inner core 104 contains iron as a main component. The inner core 104 may contain, for example, 97% or more iron and 3% or less silicon as components.

[0018] The inner core 104 may be formed by stacking a plurality of non-oriented electromagnetic steel sheets in the direction of the rotation axis 106. Alternatively, the inner core 104 may be formed using 3D printing technology from a material that is easy to mold, such as a powder magnetic core material or soft magnetic metal powder.

[0019] The rotor 102 has a magnet-embedded configuration in which the magnets 105 are embedded inside the inner core 104 so that they are not exposed on the surface of the inner core 104 .

[0020] The stator 103 includes an outer core 108 and a plurality of windings 109. The outer core 108 is a magnetic core including a plurality of magnetic blocks 120 that are circumferentially arranged and connected to one another. In the example of Fig. 2, twelve magnetic blocks 120 are provided.

[0021] Fig. 3 is a perspective view showing one magnetic block 120 and one winding 109 of the stator 103 of Fig. 2. Fig. 4 is a cross-sectional view showing one magnetic block 120 and one winding 109 of the stator 103 of Fig. 2. In Fig. 4, "O" indicates the center of the rotation shaft 106.

[0022] As shown in FIG. 4, the magnetic block 120 includes a base 131 connected to an adjacent magnetic block 120, and a protrusion 132 protruding from the base 131 toward the center O of the rotation shaft 106 (or the inner core 104).

[0023] The winding 109 is wound around the protrusion 132. The winding 109 is, for example, a rectangular wire. The cross-sectional shape of the winding 109 may have different thicknesses and / or different widths depending on the position. In this case, the winding 109 is actually formed in advance into a coil shape to match the shape of the protrusion 132, and then attached to the magnetic block 120 as described below with reference to FIGS. 5A to 5D. The coil-shaped winding 109 may be formed using, for example, 3D printing technology. An insulating bobbin (not shown) may be provided between the winding 109 and the magnetic block 120.

[0024] The magnetic material block 120 includes magnetic material components 121 to 123, each of which includes a portion of the protrusion 132 divided in the circumferential direction. The magnetic material block 120 is divided into the magnetic material components 121 to 123 on two planes parallel to a reference plane passing through the center of the magnetic material block 120 in the circumferential direction (i.e., a plane including line OA in FIG. 4 and a straight line (center line) passing through the center O of the rotation shaft 106 and extending in the axial direction). In other words, the magnetic material components 121 to 123 are connected to each other at joining surfaces 124 and 125 parallel to this reference plane. The magnetic material components 121 to 123 are connected to each other using, for example, an adhesive. In the magnetic material block 120, the magnetic material component 121 is located at the center in the circumferential direction, and the magnetic material components 122 and 123 are located at both ends in the circumferential direction.

[0025] The length of the protrusions 132 in the circumferential direction is widened at the tips of the protrusions 132 so as to facilitate the formation of a desired magnetic path between the rotor 102 and the stator 103. In other words, the length of the tips of the protrusions 132 in the circumferential direction is wider than the circumferential length of the portion of the protrusions 132 around which the winding 109 is wound. For example, the length of the tips of the protrusions 132 in the circumferential direction may be longer than the inner diameter of the winding 109 in the circumferential direction.

[0026] The magnetic part 121 may have the same magnetic properties as the magnetic parts 122 and 123, or may have different magnetic properties.

[0027] When the magnetic components 121 to 123 have the same magnetic properties, the magnetic components 121 to 123 may contain 96.5 to 97% iron and 3 to 3.5% silicon as their components. By using magnetic components 121 to 123 made of the same material, the magnetic block 120 can be mass-produced inexpensively.

[0028] On the other hand, when the magnetic substance component 121 has magnetic properties different from those of the magnetic substance components 122 and 123, the magnetic substance components 122 and 123 may have a saturation magnetic flux density higher than that of the magnetic substance component 121. In this case, the magnetic substance components 122 and 123 may be permendur containing 49% iron, 49% cobalt, and 2% vanadium as components, and the magnetic substance component 121 may contain 96.5 to 97% iron and 3 to 3.5% silicon as components.

[0029] Furthermore, when the magnetic substance component 121 has magnetic properties different from those of the magnetic substance components 122 and 123, the magnetic substance component 121 may have an iron loss lower than that of the magnetic substance components 122 and 123. In this case, the magnetic substance component 121 may contain approximately 94% iron and approximately 6% silicon as its components, and the magnetic substance components 122 and 123 may contain 96.5 to 97% iron and 3 to 3.5% silicon as its components. In this case, the magnetic substance components 122 and 123 may be made of an amorphous material or the like having low iron loss.

[0030] In FIG. 4 , the thick dashed line indicated by the symbol "F" indicates the magnetic flux passing through the magnetic material block 120. Referring to FIGS. 2 and 4 , the magnetic flux F circulates by passing through the protrusion 132, the magnet 105, and the inner core 104, the protrusion 132 and the base 131 of the adjacent magnetic material block 120, the base 131 of the original magnetic material block 120, and then returning to the original protrusion 132. In this case, the magnetic flux density is high in the portion of the magnetic material block 120 closer to the winding 109, i.e., on the surfaces of the magnetic material components 122 and 123, and low in the portion of the magnetic material block 120 farther from the winding 109, i.e., the magnetic material component 121. Therefore, by making the saturation magnetic flux density of the magnetic material components 122 and 123 higher than that of the magnetic material component 121, the magnetic flux density of the magnetic material block 120 can be effectively improved and high torque can be achieved while minimizing the amount of expensive materials, including rare metals, used. Furthermore, by making the iron loss of the magnetic part 121 lower than the iron loss of the magnetic parts 122 and 123, the iron loss of the magnetic block 120 can be reduced.

[0031] 2 , by connecting a plurality of magnetic blocks 120 arranged in the circumferential direction, the bases 131 of these magnetic blocks 120 form an annular yoke, and the protrusions 132 of each magnetic block 120 protrude inward of the yoke and extend radially. The protrusions 132 are arranged at equal intervals along the inner circumference of the yoke so that the tip of each protrusion 132 faces the inner core 104.

[0032] The magnetic material components 121 to 123 of the outer core 108 may be formed by stacking a plurality of non-oriented electromagnetic steel sheets in the direction of the rotation axis 106. Alternatively, the magnetic material components 121 to 123 of the outer core 108 may be formed using 3D printing technology from materials such as powder magnetic core materials and soft magnetic metal powders that are easy to mold.

[0033] The inner core 104 and the outer core 108 are formed to be rotatable relative to each other around a common rotation axis 106. The inner core 104 is disposed inside the outer core 108 so that the tips of the protrusions 132 of the outer core 108 face the outer peripheral surface of the rotor 102 with a gap therebetween.

[0034] The rotor 102 and stator 103 configured in this manner are disposed inside a housing 110 as shown in Figure 1 to form a motor 101. A rotating shaft 106 extends in the axial direction from the inner core 104, and one end of the rotating shaft 106 protrudes outside the housing 110 as an output shaft for driving a load to rotate.

[0035] The motor 101 may be a brushless motor driven by a three-phase AC including a U-phase, a V-phase, and a W-phase that are 120 degrees out of phase with each other. A current of any one of the U-phase, V-phase, and W-phase is applied to the multiple windings 109.

[0036] 5A to 5D are top views showing first to fourth steps of assembling one magnetic block 120 of the stator 103 of FIG.

[0037] As described above, the length of the tip of the protrusion 132 in the circumferential direction may be longer than the inner diameter of the winding 109. In this case, the winding 109, which has been formed into a coil shape in advance, is attached to the magnetic block 120 as shown in Figures 5A to 5D.

[0038] First, as shown in FIG. 5A, one of the magnetic parts 122 and 123 at both ends in the circumferential direction, the magnetic part 122 in the example of FIG. 5A, is inserted into the winding 109.

[0039] Next, as shown in Fig. 5B , the other of the magnetic material components 122, 123 (in the example of Fig. 5B , magnetic material component 123) is inserted into the winding 109. The magnetic material components 122, 123 have mirror-symmetric shapes. In order to insert the magnetic material components 122, 123 into the winding 109, the magnetic material components 122, 123 have dimensions that satisfy d2 + d3 < d1. Here, d1 represents the inner diameter of the winding 109 in the circumferential direction, d2 represents the circumferential length of the portions of the magnetic material components 122, 123 around which the winding 109 is wound, and d3 represents the circumferential length of the tips of the magnetic material components 122, 123.

[0040] Next, as shown in FIG. 5C, after both the magnetic material parts 122 and 123 are inserted into the winding 109, the magnetic material parts 122 and 123 are separated from each other.

[0041] Next, as shown in Fig. 5D , the remaining magnetic substance component 121 is inserted between the magnetic substance components 122 and 123. In Fig. 5D , d11 indicates the circumferential length of the portion of the protrusion 132 around which the winding 109 is wound, d12 indicates the circumferential length of the magnetic substance component 121, and d13 indicates the circumferential length of the tip of the protrusion 132. The length d11 satisfies d11 = d2 × 2 + d12, and the length d13 satisfies d13 = d3 × 2 + d12. The magnetic substance component 121 is connected to the magnetic substance components 122 and 123 using an adhesive.

[0042] According to the processing of Figures 5A to 5D, even if the length d13 of the tip of the protrusion 132 in the circumferential direction is longer than the inner diameter d1 of the winding 109 in the circumferential direction, the winding 109, which has been formed in advance into a coil shape, can be attached to the magnetic block 120 as long as d2 + d3 < d1 is satisfied.

[0043] After the winding 109 is attached to the magnetic block 120, the bases 131 of the magnetic blocks 120 that are arranged circumferentially and adjacent to each other may be connected to each other, for example, by welding, or may be connected to each other by laser cladding (laser powder deposition method) in additive manufacturing.

[0044] [Motor operation]

[0045] FIG. 6 is a cross-sectional view showing a magnetic material block 140 and a winding 109 according to a first comparative example. The magnetic material block 140 is an example of a magnetic material block made up of multiple magnetic material components according to conventional technology. The magnetic material block 140 has the same shape and dimensions as the magnetic material block 120 according to the embodiment. However, the magnetic material block 140 is divided into two magnetic material components 141 and 142 at the tip of the protrusion (the lower end in the Y direction in the example of FIG. 6). The magnetic material components 141 and 142 are connected to each other, for example, at a flat joint surface 143. After the protrusion of the magnetic material component 141 is inserted into the winding 109, the magnetic material component 142 is adhered to the tip of the protrusion of the magnetic material component 141.

[0046] 7 is a cross-sectional view showing a magnetic material block 150 and a winding 109 according to a second comparative example. The magnetic material block 150 is also an example of a magnetic material block made up of multiple magnetic material components according to the prior art. The magnetic material block 150 has the same shape and dimensions as the magnetic material block 120 according to the embodiment. However, the magnetic material block 150 is divided into two magnetic material components 151 and 152 corresponding to the base and protrusion, respectively. The magnetic material components 151 and 152 are connected to each other at a joint surface 153 formed to fit together. After the magnetic material component 152 is inserted into the winding 109, the magnetic material component 152 is fitted into the magnetic material component 151.

[0047] FIG. 8 is a graph showing the rate of change in torque when the gap between the joining surfaces of the magnetic components is changed for the magnetic block 120 according to the example, the magnetic block 140 according to the first comparative example, and the magnetic block 150 according to the second comparative example. The gaps between the joining surfaces 124 and 125 of the magnetic components 121-123, the gap between the joining surface 143 of the magnetic components 141-142, and the gap between the joining surface 153 of the magnetic components 151-152 were set to 0.001 mm, 0.01 mm, or 0.1 mm, respectively, and the rate of change in torque was calculated based on the torque when the joining surface gap was 0 mm. The magnetic components in the magnetic blocks 120, 140, and 150 are made of the same magnetic material. When the joining surface gap is not zero, it is assumed that adhesive is present between the magnetic components. Generally, the larger the joining surface gap, the lower the torque. However, as shown in FIG. 8, the torque reduction rate of the magnetic block 120 according to the example is smaller than that of the magnetic blocks 140 and 150 according to the comparative examples.

[0048] 6 and 7, the magnetic flux F intersects with the joining surfaces 143, 153, and therefore there is a risk that the flow of the magnetic flux F will be hindered due to gaps and adhesive at the joining surfaces 143, 153. On the other hand, with reference to Fig. 4, the magnetic flux F does not intersect with the joining surfaces 124, 125 of the magnetic material components 121 to 123, and therefore, it is thought that the effect on the magnetic flux F of dividing the magnetic material block 120 into the magnetic material components 121 to 123 is relatively small, and as a result, the rate of decrease in torque is small.

[0049] Figure 9 is a graph showing the rate of change in torque when the width of the magnetic component 121 and the gap between the joining surfaces of the magnetic components 121-123 are changed for the magnetic block 120 according to the example. The length ratio d12 / d11 shown in Figure 5D was set to 0.33, 0.5, or 0.66, and the rate of change in torque was calculated based on the torque when the gap between the joining surfaces 124 and 125 was 0 mm. If the gap between the joining surfaces 124 and 125 is not 0 mm, it is assumed that adhesive is present between the magnetic components. According to Figure 9, the smaller the length ratio d12 / d11, the smaller the rate of torque decrease.

[0050] 4, the magnetic flux F flows substantially parallel to the joining surfaces 124, 125. It is believed that the greater the distance between the joining surfaces 124, 125 and the magnetic flux F, the smaller the effect on the magnetic flux F caused by dividing the magnetic block 120 into the magnetic components 121 to 123, and as a result, the smaller the rate of torque reduction.

[0051] According to the motor 101 of the first embodiment, even when each magnetic block 120 of the outer core 108 is made up of multiple magnetic components 121 to 123, it is possible to achieve torque that is higher than conventional motors. Furthermore, it is possible to generate the same torque as conventional motors with a smaller current than conventional motors. Furthermore, when generating the same torque as conventional motors with the same current, it is possible to reduce the axial thickness of the inner core 104 and the outer core 108, thereby enabling the motor 101 to be made smaller than conventional motors.

[0052] As shown in Figure 6, when the magnetic component 142 is bonded to the tip of the protrusion of the magnetic component 141, it is difficult to ensure sufficient strength through bonding, making it unsuitable for mass production. Furthermore, as shown in Figure 7, when the magnetic component 152 is fitted to the magnetic component 151, it is difficult to reduce variations between magnetic blocks 150, and rotation ripples may occur. On the other hand, according to the first embodiment, the magnetic components 121 to 123 can be connected to each other with greater strength than in the case of Figure 6. Furthermore, according to the first embodiment, the magnetic components 121 to 123 are connected to each other at the flat joining surfaces 124 and 125, so it is easier to reduce variations between magnetic blocks 120 than in the case of Figure 7.

[0053] [Modification of the First Embodiment] FIG. 10 is a perspective view showing a magnetic block 120A and one winding 109 according to a first modification of the first embodiment. The magnetic block 120A includes magnetic components 121A to 123A. The magnetic components 121A to 123A are configured substantially similarly to the magnetic components 121 to 123 shown in FIGS. 3 and 4 . However, the magnetic components 121A to 123A have fitting portions 160 formed to fit together in the circumferential direction at positions remote from the inner core 104 (ends in the +Y direction in FIG. 10 ). The magnetic component 121A has two protrusions 161, the magnetic component 122A has a recess 162, and the magnetic component 123A has a recess 163. In the example of FIG. 10 , the fitting portions 160 form a dovetail joint. 10, the magnetic part 121A is inserted between the magnetic parts 122A and 123A, and the convex part 161 and the concave parts 162 and 163 fit together. By fitting the magnetic parts 121A to 123A together at the fitting part 160, the magnetic parts 121A to 123A can be more reliably connected and less likely to become misaligned than when multiple magnetic parts are connected using only adhesive. Furthermore, by providing the fitting part 160 at a position remote from the internal core 104, the effect on the flow of magnetic flux can be reduced.

[0054] FIG. 11 is a side view showing a magnetic block 120B according to a second modified example of the first embodiment. FIG. 11 shows the magnetic block 120B as seen from the outside of the stator. The magnetic block 120B includes magnetic components 121B to 123B. The magnetic components 121B to 123B are configured substantially similarly to the magnetic components 121 to 123 shown in FIGS. 3 and 4 . However, the magnetic components 121B to 123B have fitting portions 160B formed at positions remote from the inner core 104 so as to fit together in the circumferential direction. In the example shown in FIG. 11 , the fitting portions 160B have rectangular convex and concave portions. The fitting portions 160B in FIG. 11 also provide the same effect as the fitting portion 160 in FIG. 10 .

[0055] FIG. 12 is a side view showing a magnetic block 120C according to a third modified example of the first embodiment. FIG. 12 shows the magnetic block 120C as seen from the outside of the stator. The magnetic block 120C includes magnetic components 121C to 123C. The magnetic components 121C to 123C are configured substantially similarly to the magnetic components 121 to 123 shown in FIGS. 3 and 4 . However, the magnetic components 121C to 123C each have a fitting portion 160C formed at a position remote from the inner core 104 so as to fit together in the circumferential direction. In the example shown in FIG. 12 , the fitting portion 160C has a trapezoidal convex portion that tapers gradually and a complementary concave portion. The fitting portion 160C in FIG. 12 also provides the same effect as the fitting portion 160 in FIG. 10 .

[0056] The magnetic part may have a fitting portion having a shape different from that of the examples of FIGS.

[0057] The fitting portion is not limited to being provided at a position remote from the inner core 104, i.e., only on the outer periphery of the stator. The fitting portion may extend to a predetermined depth while maintaining the shape at the outer periphery, or may penetrate from the outer periphery to the inner periphery of the stator while maintaining the shape at the outer periphery.

[0058] Second Embodiment The magnetic block is not limited to being divided on two planes parallel to each other, but may be divided on a plane along the radial direction.

[0059] 13 is a cross-sectional view showing a magnetic block 120D and one winding 109 according to the second embodiment. The magnetic block 120D includes magnetic components 121D to 123D, each of which includes a portion of a protrusion divided in the circumferential direction. The magnetic block 120D is divided into magnetic components 121D to 123D on two planes along the radial direction (i.e., lines OB and OC). In other words, the magnetic components 121D to 123D are connected to each other at joining surfaces 124D and 125D along the radial direction.

[0060] Figure 14 is a graph showing the rate of torque change for the magnetic block 120D of the example when the width of the magnetic component 121D and the gap between the joining surfaces of the magnetic components 121D-123D are varied. The length ratio d22 / d21 shown in Figure 13 was set to 0.33, 0.5, or 0.66, and the rate of torque change was calculated based on the torque when the gap between the joining surfaces 124D and 125D was 0 mm. When the gap between the joining surfaces 124D and 125D is not 0 mm, it is assumed that adhesive is present between the magnetic components. Figure 13 shows that the smaller the length ratio d22 / d21, the smaller the rate of torque decrease. Figure 13 shows that torque roughly equivalent to that of Figure 9 can be achieved.

[0061] According to the second embodiment, as in the first embodiment, even when each magnetic block 120D of the outer core is made up of multiple magnetic parts 121D to 123D, it is possible to achieve torque that is better than conventional.

[0062] Furthermore, according to the second embodiment, the magnetic block is divided along a radial plane, which makes it easier to insert the magnetic part 121D between the magnetic parts 122D and 123D, and also makes it less likely for the magnetic part 121D to protrude from the magnetic parts 122D and 123D toward the inner core when inserted. As a result, according to the second embodiment, the magnetic block 120D can be manufactured more easily than the magnetic block 120 according to the first embodiment.

[0063] Third Embodiment The magnetic block is not limited to having three magnetic components, and may have two magnetic components.

[0064] 15 is a cross-sectional view showing a magnetic block 120E and one winding 109E according to the third embodiment. The magnetic block 120E includes magnetic components 121E and 122E, each of which includes a portion of a protrusion divided in the circumferential direction. The magnetic block 120E is divided into the magnetic components 121E and 122E on a plane passing through the center of the magnetic block 120E in the circumferential direction. In other words, the magnetic components 121E and 122E are connected to each other at a joining surface 123E.

[0065] FIG. 16 is a top view illustrating the assembly of the magnetic block 120E of FIG. 15. First, one of the magnetic parts 121E and 122E, i.e., the magnetic part 121E in the example of FIG. 16, is inserted into the winding 109E. Next, the other of the magnetic parts 121E and 122E, i.e., the magnetic part 122E in the example of FIG. 16, is inserted into the winding 109E while tilted at a predetermined angle θ (0<θ<90 degrees) relative to the radial direction. The magnetic parts 121E and 122E have mirror-symmetric shapes. To insert the magnetic parts 121E and 122E into the winding 109E, the magnetic parts 121E and 122E have dimensions that satisfy d33 + d34 < d31. Here, d31 denotes the inner diameter of the winding 109E in the circumferential direction, d33 denotes the circumferential length of the portion of the magnetic material components 121E and 122E around which the winding 109E is wound, and d34 denotes the length of the tip of the magnetic material component 122E in the circumferential direction when the magnetic material component 122E is tilted. The lengths d33 and d34 and the tilt angle θ are determined according to the inner diameter d31 and height d32 of the winding 109E. As shown in Figure 16, even if the length of the tip of the protrusion in the circumferential direction is longer than the inner diameter of the winding 109E in the circumferential direction, the winding 109E, which has been pre-formed into a coil shape, can be attached to the magnetic material block 120E.

[0066] According to the third embodiment, as in the first embodiment, even when each magnetic block 120E of the outer core is made up of multiple magnetic parts 121E, 122E, it is possible to achieve torque that is better than conventional.

[0067] Other Embodiments The disclosed embodiments and modifications may be combined as appropriate.

[0068] Each magnetic block is not limited to having two or three magnetic components, but may have four or more magnetic components each including a portion of the circumferentially divided protrusion.

[0069] The magnetic blocks according to the second and third embodiments may also have a fitting portion, similar to the examples of FIGS.

[0070] The winding wire is not limited to a rectangular wire, but may be any conductor pre-formed into a coil shape (for example, a conductor having a cross-sectional shape such as a square or circular shape).

[0071] In the embodiment, a motor having an inner rotor configuration with a rotor inside a stator, a magnet on the rotor, and a winding on the stator has been described. However, the principles described can also be applied to motors having an outer rotor configuration with a rotor outside a stator, and to motors having windings on the rotor and magnets on the stator.

[0072] The embodiment described above is not limited to a motor, but can also be applied to other rotating electrical machines such as generators.

[0073] Summary of the Embodiments A rotating electric machine according to each aspect of the present disclosure is configured as follows.

[0074] A rotating electric machine according to a first aspect of the present disclosure comprises: first and second magnetic cores formed to be rotatable relative to each other around a common rotation axis; a plurality of magnets provided in the first magnetic core; and a plurality of windings wound around the second magnetic core; the second magnetic core comprises a plurality of magnetic blocks arranged circumferentially about the rotation axis and connected to each other; each of the plurality of magnetic blocks comprises a base connected to an adjacent magnetic block and a protrusion protruding from the base toward the first magnetic core; each of the plurality of windings is wound around the protrusion of one of the plurality of magnetic blocks; and each of the plurality of magnetic blocks comprises a plurality of magnetic components each including a portion of the protrusion divided in the circumferential direction.

[0075] According to the rotating electric machine of the second aspect of the present disclosure, in the rotating electric machine of the first aspect, each of the plurality of magnetic blocks includes three magnetic components each including a portion of the protrusion divided in the circumferential direction.

[0076] According to the rotating electric machine of the third aspect of the present disclosure, in the rotating electric machine of the second aspect, in each of the plurality of magnetic blocks, the three magnetic components are connected to each other in two planes parallel to a reference plane passing through the center of the magnetic block in the circumferential direction.

[0077] According to the rotating electric machine of the fourth aspect of the present disclosure, in the rotating electric machine of the second aspect, in each of the plurality of magnetic blocks, the three magnetic components are connected to each other in two planes radially aligned with the rotation axis.

[0078] According to a rotating electric machine according to a fifth aspect of the present disclosure, in the rotating electric machine according to one of the second to fourth aspects, in each of the plurality of magnetic blocks, the three magnetic material components include a first magnetic material component at the center in the circumferential direction and second and third magnetic material components at both ends in the circumferential direction, and the first magnetic material component has magnetic properties different from the magnetic properties of the second and third magnetic material components.

[0079] According to the rotating electric machine according to the sixth aspect of the present disclosure, in the rotating electric machine according to the fifth aspect, in each of the plurality of magnetic blocks, the second and third magnetic components have a saturation magnetic flux density higher than the saturation magnetic flux density of the first magnetic component.

[0080] According to the rotating electric machine according to the seventh aspect of the present disclosure, in the rotating electric machine according to the fifth or sixth aspect, in each of the plurality of magnetic blocks, the first magnetic component has an iron loss lower than the iron loss of the second and third magnetic components.

[0081] According to the rotating electric machine of the eighth aspect of the present disclosure, in the rotating electric machine of one of the first to seventh aspects, in each of the plurality of magnetic blocks, the plurality of magnetic components have mating portions formed to fit together in the circumferential direction at a position remote from the first magnetic core.

[0082] According to a rotating electric machine according to a ninth aspect of the present disclosure, in the rotating electric machine according to the eighth aspect, the fitting portion in each of the plurality of magnetic blocks includes a dovetail joint.

[0083] According to the rotating electric machine according to the tenth aspect of the present disclosure, in the rotating electric machine according to one of the first to ninth aspects, in each of the plurality of magnetic blocks, the length of the tip of the protrusion in the circumferential direction is longer than the inner diameter of the winding in the circumferential direction.

[0084] The present disclosure is applicable to various rotating electric machines, such as industrial servo motors, drive motors for electric vehicles or plug-in hybrid vehicles, and generators.

[0085] DESCRIPTION OF SYMBOLS 101 Motor 102 Rotor 103 Stator 104 Inner core 105 Magnet 106 Rotating shaft 107 Bearing 108 Outer core 109, 109E Winding 110 Housing 120, 120A to 120E Magnetic block 121 to 123, 121A to 123A, 121B to 123B, 121C to 123C, 121D to 123D, 121E to 122E Magnetic part 124, 125, 124D, 125D Joint surface 131 Base 132 Protrusion 160, 160B, 160C Fitting portion 161 Convex portion 162, 163 Concave portion

Claims

1. A rotating electric machine comprising: first and second magnetic cores formed to be rotatable relative to each other around a common rotation axis; a plurality of magnets provided in the first magnetic core; and a plurality of windings wound around the second magnetic core, wherein the second magnetic core comprises a plurality of magnetic blocks arranged circumferentially about the rotation axis and connected to each other, each of the plurality of magnetic blocks having a base connected to an adjacent magnetic block and a protrusion protruding from the base toward the first magnetic core, each of the plurality of windings being wound around the protrusion of one of the plurality of magnetic blocks, and each of the plurality of magnetic blocks comprising a plurality of magnetic components each including a portion of the protrusion divided in the circumferential direction.

2. A rotating electric machine according to claim 1, wherein each of the plurality of magnetic blocks comprises three magnetic components each including a portion of the protrusion divided in the circumferential direction.

3. A rotating electric machine according to claim 2, wherein in each of said plurality of magnetic blocks, said three magnetic components are connected to each other in two planes parallel to a reference plane passing through the center of said magnetic block in the circumferential direction.

4. The rotating electric machine according to claim 2, wherein in each of said plurality of magnetic blocks, said three magnetic components are connected to each other on two planes extending radially relative to said rotation axis.

5. A rotating electric machine according to any one of claims 2 to 4, wherein in each of the plurality of magnetic blocks, the three magnetic components include a first magnetic component at the center in the circumferential direction and second and third magnetic components at both ends in the circumferential direction, and the first magnetic component has magnetic properties different from the magnetic properties of the second and third magnetic components.

6. A rotating electric machine according to claim 5, wherein in each of said plurality of magnetic blocks, said second and third magnetic components have a saturation magnetic flux density higher than a saturation magnetic flux density of said first magnetic component.

7. The rotating electric machine according to claim 5, wherein in each of said plurality of magnetic blocks, said first magnetic component has an iron loss lower than the iron losses of said second and third magnetic components.

8. A rotating electric machine according to claim 1, wherein in each of said plurality of magnetic blocks, said plurality of magnetic components have fitting portions formed so as to fit together in the circumferential direction at a position remote from said first magnetic core.

9. The rotating electric machine according to claim 8, wherein in each of said plurality of magnetic blocks, said fitting portion includes a dovetail joint.

10. A rotating electric machine according to claim 1, wherein in each of said plurality of magnetic blocks, the length of the tip of said protrusion in said circumferential direction is longer than the inner diameter of said winding in said circumferential direction.

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