Embedded magnet type rotating electric machine and electric device

Abstract

The present invention provides an embedded magnet type rotating electric motor and an electric device, the embedded magnet type rotating electric motor comprises a stator and a rotor, the rotor has a rotor core with a plurality of permanent magnets embedded therein, and is rotatably held on the inner side of the stator with a rotating shaft as the center, the plurality of permanent magnets are held on the outer peripheral portion of the rotor core at intervals in the circumferential direction and have magnetic poles at both end portions in the circumferential direction, and the rotor core has a plurality of lightening holes arranged at intervals in the circumferential direction on the rotating shaft side of the plurality of permanent magnets. Each of the plurality of lightening holes has a bottom wall surface portion extending in the circumferential direction on the rotating shaft side, an outer circumferential wall surface portion on the outer circumferential side, and a side wall surface portion connecting the bottom wall surface portion and the outer circumferential wall surface portion. The outer circumferential wall surface portion has an inclined wall surface portion approaching the rotating shaft from the center portion of one of the plurality of permanent magnets toward the magnetic pole side.

Description

Technical Field

[0001] The present invention relates to an embedded magnet type rotating electric motor and an electric device using the same, and more particularly to an embedded magnet type rotating electric motor and an electric device equipped with the embedded magnet type rotating electric motor, the embedded magnet type rotating electric motor comprising: a stator having a stator coil; and a rotor having a rotor core in which a plurality of permanent magnets are embedded and held rotatably around a rotating axis on the inner side of the stator. Background Art

[0002] There are various technologies for improving an embedded magnet type rotating electric motor (IPM motor), which includes: a stator having a stator coil; and a rotor having a rotor core in which a plurality of permanent magnets are embedded and a rotor that can be held rotatably around a rotating shaft on the inner side of the stator. For example, Japanese Patent Publication No. 2012-235608 describes the following technology: a plurality of thin plate-shaped high magnetic permeability components having a magnetic permeability higher than that of the material of the rotor core are stacked in a substantially radial direction at the outer peripheral side of the circumferential end of the permanent magnet in the rotor core embedded in the rotor. Japanese Patent Publication No. 2012-235608 describes that by adopting the above-mentioned structure, eddy currents can be suppressed at the ends of the permanent magnets, thereby avoiding damage to the reliability of the structure. In addition, Japanese Patent Publication No. 2012-235608 describes that a weight-reducing recess is formed on the rotor core in order to achieve lightweighting of the rotor core. The weight-reducing recess can achieve lightweighting of the rotor core.

[0003] However, Japanese Patent Application Publication No. 2012-235608 does not describe a method for improving the responsiveness of torque changes. If the responsiveness of the torque changes of the embedded magnet type rotating electric motor is high, the rotational force of the embedded magnet type rotating electric motor can be controlled more finely. Therefore, even if the technology described in Japanese Patent Application Publication No. 2012-235608 is used, it is not easy to improve the responsiveness of the torque changes of the embedded magnet type rotating electric motor. Summary of the invention

[0004] An object of the present invention is to provide an embedded magnet type rotating electric motor capable of suppressing a decrease in torque and improving responsiveness of torque changes, and an electric device equipped with the embedded magnet type rotating electric motor.

[0005] A method of the embedded magnet type rotating motor of the present invention for solving the above-mentioned problems includes: a stator having a stator coil; and a rotor, which has a rotor core with a plurality of permanent magnets embedded therein and is rotatably held on the inner side of the stator with a rotating axis as the center, wherein the plurality of permanent magnets are held at intervals from each other in the circumferential direction on the outer periphery of the rotor core and have magnetic poles at both ends in the circumferential direction, and the rotor core has a plurality of lightening holes arranged at intervals from each other in the circumferential direction on the rotating axis side of the plurality of permanent magnets, the plurality of lightening holes respectively having: a bottom wall portion extending in the circumferential direction on the rotating axis side; an outer peripheral wall portion on the outer peripheral side; and a side wall portion connecting the bottom wall portion and the outer peripheral wall portion, the outer peripheral wall portion having an inclined wall portion approaching the rotating axis as it moves from the central portion of one of the plurality of permanent magnets toward the magnetic pole side.

[0006] According to the present invention, in an internal magnet type rotating electric machine, it is possible to suppress a decrease in torque and improve the responsiveness of torque changes.

[0007] Other problems, structures, and effects than those described above will become more apparent from the following description of the embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic side view of an example of an electric device according to an embodiment.

[0009] Figure 2 is a schematic cross-sectional view of an embedded magnet type rotating electric machine.

[0010] Figure 3 1 is a schematic cross-sectional view of a rotor 100 of an embedded magnet type rotating electric machine.

[0011] Figure 4 1 is a schematic cross-sectional view of a rotor 100 of an embedded magnet type rotating electric machine.

[0012] Figure 5 This is an example of a graph showing relative values ​​of the magnitude of the moment of inertia of the rotor with respect to the angle α [deg].

[0013] Figure 6 This is an example of a graph showing relative values ​​of the magnitude of torque with respect to the angle α [deg].

[0014] Figure 7 1 is a schematic cross-sectional view of a rotor 100 of an embedded magnet type rotating electric machine.

[0015] Figure 8 1 is a schematic cross-sectional view of a rotor 100 of an embedded magnet type rotating electric machine. DETAILED DESCRIPTION

[0016] Hereinafter, the embodiments will be described with reference to the accompanying drawings. Figure 2 to Figure 4 , Figure 7 , Figure 8 In order to facilitate the observation of the drawings, the hatching for cross-section display is omitted. In addition, in the drawings and descriptions of the embodiments, the same reference numerals are marked on the same parts, but the present invention is not limited to the embodiments, and all application examples that conform to the concept of the present invention are included in the technical scope of the present invention. In addition, the position, size, shape, range, number, etc. of each element shown in the drawings, etc. are examples shown to facilitate the understanding of the invention, and the position, size, shape, range, number, etc. of each element are not limited to the contents disclosed in this specification and drawings.

[0017] <<Overall Structure>>

[0018] <Structure of Electric Device 500>

[0019] Figure 1 It is a schematic side view of an example of the electric device 500 according to the present embodiment. Figure 1 The electric device 500 shown is an example of an electric device equipped with an embedded magnet type rotating electric motor 1, and is a robot arm having a main body 510, a joint 520, an arm 530, and a power supply unit 540. The electric device 500 can be bent at the joint 520 between the main body 510 and the arm 530. The embedded magnet type rotating electric motor 1 for controlling the bending of the arm 530 at the joint 520 is provided inside the joint 520. The power supply unit 540 supplies power to the embedded magnet type rotating electric motor 1.

[0020] Figure 1 The electric device 500 shown is an example of an electric device equipped with the embedded magnet type rotating electric motor 1. The electric device 500 may be any device as long as it uses the embedded magnet type rotating electric motor 1 as a driving source. The electric device 500 may be, for example, a hybrid vehicle, an electric vehicle, a railway vehicle or other vehicle, an industrial robot, a vending machine, or a servo press.

[0021] <Structure of embedded magnet type rotating electric motor 1>

[0022] Figure 2 1 is a schematic cross-sectional view of an embedded magnet type rotating electric machine 1. Figure 2 As shown, the embedded magnet type rotating electric machine 1 includes a rotor 100, a shaft 200, and a stator 300. Figure 2 The rotor 100 shown is an example of a rotor 100. Figure 21 shows a rotor 100a described later. Hereinafter, rotors 100a to 100d will be described as examples of embodiments. "Rotor 100" is a general term for rotors 100a to 100d.

[0023] The rotor 100 is held by the shaft 200 on the inner side of the stator 300. The shaft 200 is rotatably held in the embedded magnet type rotating electric machine 1. Therefore, the rotor 100 is rotatably held on the inner side of the stator 300 with the rotation axis of the shaft 200 as the center. The rotor 100 has a rotor core 110 in which 10 permanent magnets 130 are embedded, and the details will be described later. In addition, the number of permanent magnets 130 is more than 2, and can also be a number other than 10. In addition, the rotor core 110 is provided with a weight reduction hole (part of the material of the workpiece is removed to achieve a weight reduction effect) 120 as a through hole.

[0024] The stator 300 has a cylindrical yoke 311 and teeth 312 protruding inward from the yoke 311 and around which stator coils 320 are wound. Ten teeth 312 and ten stator coils 320 are provided, which is the same number as the permanent magnets 130 .

[0025] The rotor 100 can rotate relative to the stator 300 due to the magnetic force of the stator coil 320 of the stator 300 and the magnetic force of the permanent magnet 140 of the rotor 100. The number of teeth 312 and stator coil 320 may be two or more, and may be other than twelve.

[0026] <<Structure of rotor 100>>

[0027] The rotors 100a, 100b, 100c, and 100d described below are examples of the rotor 100. The shapes of the weight-reducing holes 120 are different between the rotors 100a to 100d. As described below, the rotor 100a (see Figure 3 ) has a weight-reducing hole 120a. The rotor 100b (refer to Figure 4 ) has a weight-reducing hole 120b that is arranged differently from the weight-reducing hole 120a. The rotor 100c (refer to Figure 7 ) has a weight-reducing hole 120c formed with a curved surface at a corner. The rotor 100d (refer to Figure 8 ) has lightening holes 120d1 and 120d2 that divide the lightening hole 120a into two.

[0028] <Structure of rotor 100a>

[0029] Figure 3 1 is a schematic cross-sectional view of a rotor 100a of an embedded magnet type rotating electric machine 1. Figure 3 As shown, the rotor 100 a has a rotor core 110 .

[0030] The rotor core 110 is formed by stacking thin plate-shaped electromagnetic steel sheets in the axial direction, and the thin plate-shaped electromagnetic steel sheets are formed by covering the surface of thin (for example, 0.25 to 0.35 mm) electromagnetic steel sheets punched out by press working with a thin insulator. The rotor core 110 is formed in a cylindrical shape. The rotor core 110 is held by the shaft 200 at the center. As described above, the shaft 200 is rotatably held in the embedded magnet type rotating motor 1. Therefore, the rotor 100a is rotatably held inside the stator 300 with the rotation axis of the shaft 200 as the center.

[0031] The rotor core 110 a includes magnet housing holes 111 for holding the permanent magnets 130 , lightening holes 120 a which are holes penetrating the thin electromagnetic steel sheets of the rotor core 110 , and bridges 112 between the lightening holes 120 adjacent to each other in the circumferential direction.

[0032] The number of magnet receiving holes 111 is 10. Ten (plural) magnet receiving holes 111 are arranged at intervals from each other in the circumferential direction on the outer periphery of the rotor core 110. As a result, ten (plural) permanent magnets 130 are held at intervals from each other in the circumferential direction on the outer periphery of the rotor core 110.

[0033] The permanent magnet 130 is formed in a rectangular cross-section. The permanent magnet 130 is held in the magnet receiving hole 111 in such a way that the long side of the rectangular cross-section faces the radially outer side of the rotor core 110. The permanent magnet 130 has magnetic poles 131a and 131b at both ends of the circumferential direction of the rotor core 110. The material of the permanent magnet 130 is a ferromagnetic body. The permanent magnet 130 can also be formed of a ferromagnetic material such as ferrite, neodymium, or samarium cobalt.

[0034] The lightening holes 120a are through holes that penetrate the thin plate-shaped electromagnetic steel sheet of the rotor core 110. Ten lightening holes 120a are arranged at intervals from each other in the circumferential direction on the rotating axis Ar side of the rotor core 110 of the permanent magnet 130. The lightening holes 120a are arranged at positions that avoid the d-axis. In other words, the lightening holes 120a are arranged between two adjacent d-axes.

[0035] In the line dividing the lightening hole 120a into two, the center line Ac extending radially outward from the rotation axis Ar of the rotor 100a is located at a position overlapping with the d-axis. Here, the d-axis is a line connecting the middle position of the magnetic poles 131a and 131b of one permanent magnet 130 to the rotation axis Ar of the rotor 100. In addition, the q-axis is a line connecting the middle position of the adjacent magnetic poles 131a and 131b of two permanent magnets 130 adjacent in the circumferential direction to the rotation axis Ar of the rotor 100.

[0036] The 10 weight-reducing holes 120a respectively have: a bottom wall surface portion 121 extending in the circumferential direction on the rotating axis Ar side of the rotor core 110; an outer peripheral wall surface portion 122 on the outer peripheral side of the rotor core 110; and two side wall surfaces 123 extending in the radial direction of the rotor 100 and connecting the bottom wall surface portion 121 and the outer peripheral wall surface portion 122.

[0037] The outer peripheral wall surface 122 has two inclined wall surface 122a. The two inclined wall surface 122a are connected on the q-axis. In addition, the two inclined wall surface 122a each has a planar portion formed of a flat surface.

[0038] The angle α[deg] formed by the inclined wall portion 122a and the inter-pole axis Ap connecting the poles 131a and 131b at both ends of the permanent magnet 130 is greater than the angle θa[deg] obtained by dividing 180 degrees by the number of permanent magnets Nm, and less than the angle 2θa[deg] obtained by dividing 360 degrees by the number of permanent magnets Nm (θa≤α≤2θa). In the rotor 100a, the number of permanent magnets Nm is 10, and θa=18[deg] (θa=18≤α≤2θa=36). By setting the angle α (θa≤α≤2θa) in this way, it is possible to take into account both the suppression of the reduction of the magnetic force around the poles 131a and 131b of the permanent magnet 130 due to the lightening holes 120a and the reduction of the moment of inertia of the rotor 100, which will be described in detail later. Other effects of the rotor 100a will be described later.

[0039] <Structure of rotor 100b( Figure 4 )>

[0040] Figure 4 1 is a schematic cross-sectional view of a rotor 100b of an embedded magnet type rotating electric machine 1. In the following description of the rotors 100b to 100d, the same reference numerals are used for the same structures as the rotor 100a, and the description thereof is omitted. Figure 4 As shown, in the rotor 100b, there is Figure 3 The rotor 100a shown has a weight reduction hole 120a at a different position than the weight reduction hole 120b. Figure 4 As shown, the weight reduction holes 120b of the rotor 100b make Figure 3 The position of the lightening hole 120a is an angle θa[deg] obtained by rotating 180 degrees around the rotation axis Ac of the rotor 100a and dividing by the number of permanent magnets Nm (θa=180 / Nm[deg]). Figure 4 The weight-reducing hole 120b of the rotor 100b shown is located at a position where the center line Ac extending radially outward from the rotation axis Ac of the rotor 100a overlaps with the d-axis. Figure 3The lightening holes 120 a of the rotor 100 a shown are located at a position where a center line Ac extending radially outward from the rotation axis Ac of the rotor 100 a overlaps with the q-axis.

[0041] <Effects of the Invention of Rotors 100a and 100b, Figure 5 , Figure 6 >

[0042] The embedded magnet type rotating electric machine 1 can reduce the weight of the rotor core 110 and the inertia moment of the rotor core 110 by using the lightening holes 120 (120a, 120b). Therefore, the embedded magnet type rotating electric machine 1 can improve the responsiveness of the torque change of the embedded magnet type rotating electric machine 1 by using the lightening holes 120.

[0043] Furthermore, the lightening hole 120 has an inclined wall surface 122a on the outer peripheral wall surface 122 that approaches the rotation axis Ar as it moves from the central portion of the permanent magnet 130 toward the magnetic pole 131a or the magnetic pole 131b. As a result, the magnetic poles 131a and 131b of the permanent magnet 130 are spaced apart from the inclined wall surface 122a of the lightening hole 120 located on the permanent magnet 130 side, thereby suppressing the reduction of the magnetic force of the magnetic poles 131a and 131b of the permanent magnet 130 due to the lightening hole 120. On the basis of suppressing the reduction of the magnetic force of the permanent magnet 130 due to the lightening hole 120, the magnetic force of the permanent magnet 130 can be transmitted to the rotor core 110 and act on the magnetic force of the stator coil 320 of the stator 300. As a result, the embedded magnet type rotating electric machine 1 can suppress the reduction of torque caused by the lightening hole 120.

[0044] As described above, the embedded magnet type rotating electric machine 1 can suppress a decrease in torque and improve the responsiveness of torque changes.

[0045] In addition, the lightening holes 120a and 120b are located at a position where the center line Ac extending radially outward from the rotation axis Ar of the rotors 100a and 100b overlaps with the d-axis or q-axis of the permanent magnet 130. Thus, the lightening holes 120a and 120b are arranged at a position with high symmetry relative to the permanent magnet 130. As a result, it is possible to suppress the magnetic force of the stator coil 320 of the stator 300 from acting unevenly on the magnetic force of the permanent magnet 130 due to the lightening holes 120, so that the rotors 100a and 100b can rotate more reliably and stably.

[0046] In the lightening hole 120a (refer to Figure 3), in the outer peripheral wall surface 122, two inclined wall surfaces 122a approaching the rotation axis Ar as they go from the central portion of the permanent magnet 130 to the magnetic pole 131a or the magnetic pole 131b are connected on the q-axis. That is, the portion on the q-axis in the outer peripheral wall surface 122 is reliably separated from the magnetic poles 131a and 131b of the permanent magnet 130. As a result, the magnetic poles 131a and 131b of the permanent magnet 130 are reliably separated from the lightening holes 120a, and the reduction of the magnetic force of the magnetic poles 131a and 131b of the permanent magnet 130 due to the lightening holes 120a can be suppressed. As a result, the embedded magnet type rotating motor 1 can more reliably suppress the reduction of torque caused by the lightening holes 120a.

[0047] In addition, in the lightening holes 120a and 120b, the inclined wall surface 122a that approaches the rotation axis Ar of the rotor core 110 as it moves from the central portion of the permanent magnet 130 toward the magnetic pole 131a or the magnetic pole 131b has a plane portion formed by a plane. As a result, the peripheral portion of the outer peripheral wall surface 122 located on the q-axis is more reliably separated from the magnetic poles 131a and 131b of the permanent magnet 130. As a result, the magnetic poles 131a and 131b of the permanent magnet 130 are reliably separated from the lightening holes 120, and the magnetic force of the magnetic poles 131a and 131b of the permanent magnet 130 can be more reliably suppressed from being reduced due to the lightening holes 120. Therefore, the embedded magnet type rotating electric machine 1 can more reliably suppress the reduction of torque caused by the lightening holes 120.

[0048] Next, use Figure 5 and Figure 6 , the weight reduction hole 120a (refer to Figure 3 ), and the lightening hole 120b (refer to Figure 4 ) are compared to illustrate.

[0049] Figure 5 This is an example of a graph showing the relative values ​​of the magnitude of the rotor's moment of inertia relative to the angle α [deg]. Figure 5 In the graph of , the relative value of the magnitude of the moment of inertia of the rotor indicates the magnitude of the moment of inertia of the rotor 100 provided with the lightening holes 120 relative to the magnitude of the moment of inertia of the rotor 100 not provided with the lightening holes 120. In other words, the relative value of the magnitude of the moment of inertia of the rotor refers to the magnitude of the moment of inertia of the rotor 100 provided with the lightening holes 120 when the magnitude of the moment of inertia of the rotor 100 not provided with the lightening holes 120 is set to 1.

[0050] like Figure 5As shown in the graph of , the smaller the angle α [deg] between the lightening holes 120a and 120b, the smaller the relative value of the magnitude of the moment of inertia of the rotor 100. Here, the difference between the lightening holes 120a and 120b is small.

[0051] Figure 6 This is an example of a graph showing the relative value of the torque with respect to the angle α [deg]. Figure 6 In the graph of , the relative value of the torque magnitude indicates the magnitude of the torque of the rotor 100 provided with the lightening holes 120 relative to the magnitude of the torque of the rotor 100 not provided with the lightening holes 120. In other words, the relative value of the torque magnitude refers to the magnitude of the torque of the rotor 100 provided with the lightening holes 120 when the magnitude of the torque of the rotor 100 not provided with the lightening holes 120 is set to 1.

[0052] The moment of inertia is proportional to the square of the radius. Therefore, the smaller the angle α [deg], the smaller the moment of inertia of the rotor 100. However, the smaller the angle α, the less the rotor core 110 exists around the magnetic poles 131a and 131b of the permanent magnet 130, so the magnetic force around the magnetic poles 131a and 131b of the permanent magnet 130 is reduced due to the weight reduction hole 120. As a result, the smaller the angle α [deg], the smaller the relative value of the torque of the rotor 100.

[0053] like Figure 6 As shown in the graph, the relative value of the torque of the rotor 100 decreases less when the angle α[deg] is between 2θa[deg] and θa[deg] (θa=180 / (the number of permanent magnets 130 Nm). On the other hand, when the angle α[deg] is between θa[deg] and 0, the decrease in the relative value of the torque of the rotor 100 becomes larger as the angle α[deg] approaches 0. The above suggests that the reduction in torque can be suppressed by setting the angle α[deg] to between 2θa and θa[deg] (θa≤α≤2θa). Therefore, based on the above, in the weight reduction holes 120a to 120d of the implementation method, the angle α[deg] is set to between 2θa and θa[deg] (θa≤α≤2θa).

[0054] As described above, the angle α[deg] formed by the inclined wall surface 122a and the inter-pole axis Ap connecting the magnetic poles 131a and 131b at both ends of the permanent magnet 130 is greater than the angle θa[deg] obtained by dividing 180 degrees by the number of permanent magnets Nm, and less than the angle 2θa[deg] obtained by dividing 360 degrees by the number of permanent magnets Nm (θa≤α≤2θa). As a result, the embedded magnet type rotating motor 1 can more reliably suppress the reduction of torque caused by the weight reduction hole 120. As a result, the embedded magnet type rotating motor 1 can more reliably suppress the reduction of torque and improve the responsiveness of torque changes.

[0055] In addition, if Figure 6 As shown in the graph, when the angle α[deg] is between θa[deg] and 0, the relative value of the torque of the rotor 100 in the lightening hole 120a whose centerline is on the q-axis is larger than that in the lightening hole 120b whose centerline is on the d-axis.

[0056] This is because, in the lightening hole 120a whose center line is located on the q-axis, there is no lightening hole 120 on the d-axis but there is a bridge portion 112. Magnetic flux flows in the bridge portion 112 formed between the lightening holes 120 adjacent to each other in the circumferential direction, and magnetic force can act more effectively to rotate the rotor 100. As a result, the embedded magnet type rotating electric machine 1 can more reliably suppress the reduction of torque.

[0057] In addition, the electric device 500 is equipped with an embedded magnet type rotating electric motor 1. The embedded magnet type rotating electric motor 1 is lightweight due to the weight-reducing holes 120, which can suppress the reduction of torque and improve the responsiveness of torque changes. As a result, the electric device 500 can be driven with lower energy due to the lightweight embedded magnet type rotating electric motor 1, and can be driven more efficiently due to the high responsiveness of torque changes of the embedded magnet type rotating electric motor 1. By driving efficiently, the electric device 500 can reduce the energy required for operation and the emission of carbon dioxide generated by operation, thereby suppressing global warming.

[0058] <Structure of rotor 100c>

[0059] Figure 7 1 is a schematic cross-sectional view of a rotor 100c of an embedded magnet type rotating electric machine 1. Figure 7 As shown, the rotor 100c has Figure 3 The corner portion of the lightening hole 120a of the rotor 100a shown is changed to a lightening hole 120c having a curved surface 120r.

[0060] Here, in the lightening hole 120c, the corner of the inclined wall surface 122 is closest to the magnet receiving hole 111 holding the permanent magnet 130. The closer the corner of the peripheral wall surface 122 is to the magnet receiving hole 111, the weaker the strength of the magnet receiving hole 111 is at the close portion.

[0061] On the other hand, in the embedded magnet type rotating electric machine 1, the corner of the outer peripheral wall surface 122 is formed by the curved surface 120r, and the front end of the corner is retreated to the inside, so that the magnet receiving hole 111 is separated from the corner of the outer peripheral wall surface 122. In this way, the strength of the magnet receiving hole 111 can be ensured by separating the weight-reducing hole 120c from the magnet receiving hole 111.

[0062] Furthermore, the corners of the lightening holes 120c are formed by the curved surfaces 120r, thereby preventing stress from concentrating on a portion of the corners of the lightening holes 120c and damaging the lightening holes 120c. As described above, the embedded magnet type rotating electric machine 1 can ensure the strength of the magnet housing hole 111 and the lightening holes 120c by forming the corners of the lightening holes 120c by the curved surfaces 120r.

[0063] <Structure of Rotor 100d>

[0064] Figure 8 1 is a schematic cross-sectional view of a rotor 100d of an embedded magnet type rotating electric machine 1. Figure 8 As shown, the rotor 100d has Figure 3 The lightening hole 120a of the rotor 100a shown is divided into lightening holes 120d1 and 120d2 by the q-axis.

[0065] The embedded magnet type rotating electric machine 1 can reduce the weight of the rotor core 110 and the inertia moment of the rotor core 110 by using the lightening holes 120d1 and 120d2. Therefore, the embedded magnet type rotating electric machine 1 can improve the responsiveness of the torque change of the embedded magnet type rotating electric machine 1 by using the lightening holes 120d1 and 120d2.

[0066] Moreover, the lightening holes 120d1 and 120d2 have an inclined wall surface 122a on the outer peripheral wall surface 122 that approaches the rotation axis Ar as it moves from the central portion of the permanent magnet 130 toward the magnetic pole 131a or the magnetic pole 131b. As a result, the magnetic poles 131a and 131b of the permanent magnet 130 are spaced apart from the inclined wall surface 122a of the lightening holes 120d1 and 120d2 located on the permanent magnet 130 side, thereby preventing the magnetic force of the magnetic poles 131a and 131b of the permanent magnet 130 from being reduced by the lightening holes 120d1 and 120d2. On the basis of preventing the magnetic force of the permanent magnet 130 from being reduced by the lightening holes 120d1 and 120d2, the magnetic force of the permanent magnet 130 can be transmitted to the rotor core 110 and act on the magnetic force of the stator coil 320 of the stator 300. Therefore, the embedded magnet type rotating electric machine 1 can suppress a reduction in torque due to the lightening holes 120d1 and 120d2.

[0067] As described above, the embedded magnet type rotating electric machine 1 can suppress a decrease in torque and improve the responsiveness of torque changes.

[0068] In addition, since there are no lightening holes 120d1 and 120d2 on the d-axis, the magnetic flux flows in the bridge portion 112 formed between the lightening holes 120d1 and 120d2 adjacent to each other in the circumferential direction, and thus the magnetic force can act more effectively to rotate the rotor 100. As a result, the embedded magnet type rotating electric machine 1 can more reliably suppress the reduction of torque.

[0069] In addition, the angle α[deg] formed by the inclined wall surface 122a and the inter-pole axis Ap of the magnetic poles 131a and 131b connecting the two ends of the permanent magnet 130 is greater than the angle θa[deg] obtained by dividing 180 degrees by the number of permanent magnets Nm and less than the angle 2θa[deg] obtained by dividing 360 degrees by the number of permanent magnets Nm (θa≤α≤2θa). As a result, the embedded magnet type rotating motor 1 can more reliably suppress the reduction of torque caused by the weight reduction hole 120. As a result, the embedded magnet type rotating motor 1 can more reliably suppress the reduction of torque and improve the responsiveness of torque changes.

[0070] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the gist of the invention.

[0071] Description of Reference Numerals

[0072] 1: Embedded magnet type rotating motor

[0073] 100, 100a~100d: Rotor

[0074] 110: Rotor core

[0075] 111: Magnet storage hole

[0076] 112: Bridge

[0077] 120, 120a~120d: weight reduction holes

[0078] 121: Bottom wall

[0079] 122: Peripheral wall face

[0080] 122a: Inclined wall surface

[0081] 122a1: Plane

[0082] 123: Sidewall face

[0083] 124: Surface

[0084] 130: Permanent magnet

[0085] 131a, 131b: Magnetic poles

[0086] 200: Axis

[0087] 300: Stator

[0088] 310: stator core

[0089] 311: Yoke

[0090] 312: Tooth

[0091] 320: Stator coil

[0092] 500: Electric device

[0093] 510: Main body

[0094] 520: Joints

[0095] 530: Arm

[0096] 540: Power Supply Department

[0097] Ar: Rotation axis

[0098] Ac: Centerline

[0099] Ap: interpolar axis

[0100] d: d-axis

[0101] q: q-axis

[0102] Nm: Number of permanent magnets

[0103] θa: Angle

[0104] α: angle.

Claims

1. An embedded magnet type rotating electric motor, comprising: A stator having a stator coil; and a rotor having a rotor core in which a plurality of permanent magnets are embedded and held rotatably around a rotating shaft on the inner side of the stator, wherein the embedded magnet type rotating electric motor is characterized in that: The plurality of permanent magnets are held at an outer peripheral portion of the rotor core at intervals from each other in the circumferential direction and have magnetic poles at both ends in the circumferential direction. The rotor core has a plurality of lightening holes arranged at intervals from each other in the circumferential direction on the rotation axis side of the plurality of permanent magnets. The plurality of lightening holes each include: a bottom wall surface extending in the circumferential direction on the rotating shaft side; an outer peripheral wall surface on the outer peripheral side; and a side wall surface connecting the bottom wall surface and the outer peripheral wall surface. The outer peripheral wall surface has an inclined wall surface that approaches the rotation axis as it goes from a central portion of one of the plurality of permanent magnets toward a magnetic pole side.

2. The embedded magnet type rotating electric motor according to claim 1, characterized in that: The lightening hole is located at a position where a center line extending radially outward from the rotation axis of the rotor overlaps with a d-axis or a q-axis of the permanent magnet.

3. The embedded magnet type rotating electric motor according to claim 2, characterized in that: The weight-reducing hole is located at a position where the center line overlaps the q-axis. The outer peripheral wall surface has two inclined wall surfaces. The two inclined wall surface portions are connected on the q-axis.

4. The embedded magnet type rotating electric motor according to claim 3, characterized in that: The weight-reducing hole is arranged at a position avoiding the d-axis.

5. The embedded magnet type rotating electric motor according to claim 1, characterized in that: An angle α[deg] between the inclined wall surface and the inter-pole axis connecting the magnetic poles at both ends of the permanent magnet is greater than an angle θa[deg] obtained by dividing 180 degrees by the number Nm of the permanent magnets, and less than an angle 2θa[deg] obtained by dividing 360 degrees by the number Nm of the permanent magnets.

6. The embedded magnet type rotating electric motor according to claim 1, characterized in that: The inclined wall surface portion has a planar portion formed by a flat surface.

7. The embedded magnet type rotating electric motor according to claim 1, characterized in that: Corners of the lightening holes are formed by curved surfaces.

8. An electric device, characterized in that: A rotary electric motor with an embedded magnet according to claim 1 is provided.

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