Rotor, and rotating electric machine

Abstract

A rotor to be used in an axial gap type rotary electric machine includes: a tabular magnet; a support member having an opening in which the magnet is disposed; a shaft having the same axis of rotation as the support member; a first member attached to the shaft; and a fixing structure for fixing the magnet in the opening. The fixing structure includes a first support surface and a second support surface sandwiching a part of the magnet in the thickness direction of the magnet. The first support surface is a part of the first member and faces the magnet.

Description

Rotor and rotating electric machine

[0001] This application claims priority to Japanese Patent Application No. 2024-090053, filed on June 3, 2024, and incorporates by reference all of the contents of that application.

[0002] Patent Document 1 discloses a rotor for use in an axial gap type rotating electric machine. The rotor includes a flat magnet and a disk-shaped rotor body that supports the magnet. The rotor body has an opening in which the magnet is disposed. The magnet is fixed in the opening with, for example, an adhesive. Hereinafter, the rotor body will be referred to as a support member.

[0003] Japanese Patent Application Laid-Open No. 2021-100329

[0004] The rotor disclosed herein is a rotor for use in an axial gap type rotating electric machine, and includes a flat magnet, a support member having an opening in which the magnet is disposed, a shaft having the same rotation axis as the support member, a first member attached to the shaft, and a fixing structure that fixes the magnet within the opening. The fixing structure includes a first support surface and a second support surface that sandwich a portion of the magnet in a direction along the thickness of the magnet. The first support surface is a surface of the first member that faces the magnet.

[0005] Fig. 1 is a schematic perspective view showing a rotor of embodiment 1. Fig. 2 is an exploded perspective view of the rotor of Fig. 1. Fig. 3 is a cross-sectional view taken along III-III of Fig. 1. Fig. 4 is a schematic cross-sectional view showing an example of a rotating electric machine including the rotor of Fig. 1. Fig. 5 is a partial cross-sectional view showing an enlarged portion of a rotor of embodiment 2. Fig. 6 is a partial cross-sectional view showing an enlarged portion of a rotor of embodiment 3.

[0006] It is desirable that the magnets be fixed to the support member with high strength. If the magnets are not fixed to the support member with high strength, the magnets may come off the support member when the rotor rotates at high speed, making it difficult to improve the output of the rotating electric machine. Even if the magnets are fixed to the support member with adhesive, the adhesive may soften depending on the heat resistance of the adhesive or the rotor's operating environment, and the magnets may come off the support member.

[0007] An object of the present disclosure is to provide a rotor in which magnets are fixed to a support member with high strength.

[0008] In the rotor of the present disclosure, the magnets are fixed to the support member with high strength.

[0009] First, embodiments of the present disclosure will be listed and described.

[0010] (1) A rotor according to an embodiment of the present disclosure is a rotor for use in an axial gap type rotating electric machine, and includes: a flat magnet; a support member having an opening in which the magnet is disposed; a shaft having the same rotation axis as the support member; a first member attached to the shaft; and a fixing structure that fixes the magnet within the opening. The fixing structure includes a first support surface and a second support surface that sandwich a portion of the magnet in a direction along the thickness of the magnet. The first support surface is a surface of the first member that faces the magnet.

[0011] The magnet sandwiched between the first and second support surfaces is firmly fixed within the opening of the support member. By firmly fixing the magnet within the opening of the support member, the magnet is less likely to come off the support member even when the rotor is rotated at high speed, thereby improving the output of the rotating electric machine. The fixing structure in which the magnet is sandwiched between the first and second support surfaces is less susceptible to the rotor's operating environment. Therefore, a rotor with the above fixing structure has a stronger fixing strength of the magnet to the support member than a rotor in which the magnet is fixed within the opening of the support member only with adhesive.

[0012] (2) In the rotor of (1) above, the magnet may have a first surface that faces the first support surface in at least a portion thereof, and the area of ​​the region on the first surface that is sandwiched between the first support surface and the second support surface may be 5% or more and 15% or less of the surface area of ​​the first surface.

[0013] If an area of ​​the first surface sandwiched between the first and second support surfaces accounts for 5% or more of the surface area of ​​the first surface, the magnet is more firmly fixed within the opening of the support member. If the area of ​​the area of ​​the first surface sandwiched between the first and second support surfaces accounts for 15% or less of the surface area of ​​the first surface, the effect of the fixing structure including the first member on the magnetic circuit is small.

[0014] (3) In the rotor of (1) or (2) above, the support member has a first surface and a second surface that are front and back surfaces, and the opening may be a through hole that opens into the first surface and the second surface of the support member.

[0015] Magnets secured only with adhesive may come off the support member depending on the operating conditions of the rotor. However, a securing structure in which the magnet is sandwiched between the first and second support surfaces allows the magnet to be firmly secured within the opening.

[0016] (4) In the rotor according to any one of (1) to (3) above, the second support surface may include a seat surface of a flange portion provided around the shaft.

[0017] The seating surface of the flange portion provided around the shaft can easily sandwich a portion of the magnet together with the first support surface. When the second support surface is the seating surface of the flange portion provided around the shaft, even if multiple magnets are arranged side by side at intervals around the rotation axis, a single flange portion can easily sandwich a portion of each magnet together with the first support surface. By adjusting the length of the flange portion protruding from the shaft, the length of the region of the magnet sandwiched between the first support surface and the second support surface can be easily adjusted.

[0018] (5) In the rotor according to any one of (1) to (4) above, the second support surface may include a surface that forms a protrusion provided on at least a portion of the periphery of the opening.

[0019] The surface forming the protrusion provided on the periphery of the opening can easily sandwich a part of the magnet together with the first support surface. When the second support surface is the surface forming the protrusion provided on the periphery of the opening, by placing the magnet in the opening of the support member, the second surface of the magnet can be easily supported by the second support surface.

[0020] (6) In the rotor according to any one of (1) to (5) above, the peripheral surface that forms the opening may include an inclined surface, and the second support surface may include the inclined surface.

[0021] If the peripheral surface forming the opening is an inclined surface, the inclined surface can also sandwich part of the magnet together with the first support surface. If the second support surface is an inclined surface forming the opening, the part forming the second support surface is located within the opening, so the fixing structure does not become too large.

[0022] (7) In the rotor according to any one of (1) to (6) above, the first member may include a push nut that is inserted through the shaft.

[0023] The push nut has angled claws on its inner circumferential surface that bite into the outer circumferential surface of the shaft when the push nut is fitted onto the shaft. Simply by attaching the push nut to the shaft, it is possible to sandwich part of the magnet together with the second support surface.

[0024] (8) In the rotor of (7) above, the first member may include a buffer member disposed between the push nut and the magnet.

[0025] If a buffer member is placed between the push nut and the magnet, damage to the magnet caused by the pressure of the push nut is unlikely to occur. If a buffer member is placed between the push nut and the magnet, even if a step is formed between the first surface of the magnet and the first surface of the support member, the step can be absorbed by the buffer member, making the surface pressure from the push nut uniform.

[0026] (9) In the rotor according to any one of (1) to (8) above, the first member may be made of a non-magnetic material.

[0027] If the first member is made of a non-magnetic material, the influence of the first member on the magnetic circuit is small.

[0028] (10) In the rotor according to any one of (1) to (9) above, the region of the magnet sandwiched between the first support surface and the second support surface may not be magnetized.

[0029] If the region of the magnet sandwiched between the first support surface and the second support surface is not magnetized, the influence on the magnetic circuit is small regardless of the magnetism of the fixed structure including the first member.

[0030] (11) In the rotor according to any one of (1) to (10) above, the fixing structure may include an adhesive provided between the magnet and the support member.

[0031] When the magnet and the support member are secured with adhesive, the magnet is more firmly fixed within the opening of the support member. Even if the adhesive softens due to its heat resistance or the rotor's operating environment, the magnet is sandwiched between the first and second support surfaces, making it less likely to come off the support member.

[0032] (12) A rotating electric machine according to an embodiment of the present disclosure includes the rotor according to any one of (1) to (11) above and one or more stators.

[0033] In a rotating electrical machine including the rotor, the magnets are unlikely to come off the support member even when the rotor is rotated at high speed, and therefore the output of the rotating electrical machine can be improved.

[0034] [Details of the embodiments of the present disclosure] Specific examples of rotors and rotating electric machines according to the present disclosure will be described with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. In the drawings, some components may be exaggerated or simplified for ease of explanation. The dimensional ratios of the various parts in the drawings may also differ from the actual ratios. Note that the present invention is not limited to these examples, but is defined by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0035] [Embodiment 1] <Rotor> A rotor 1 of embodiment 1 will be described with reference to Figures 1 to 3 and, where appropriate, Figure 4. As shown in Figures 1 to 3, the rotor 1 includes a flat magnet 2, a support member 3, and a shaft 4. The rotor 1 is used in an axial gap type rotating electric machine 8 shown in Figure 4. The rotating electric machine 8 shown in Figure 4 is a single rotor / double stator type. The single rotor / double stator type rotating electric machine 8 is assembled so that a single assembly made up of the magnet 2 and the support member 3 is sandwiched between two stators 81 along the rotation axis 5 of the shaft 4.

[0036] The support member 3 has an opening 36 in which the magnet 2 is disposed. One of the features of the rotor 1 of embodiment 1 is that it includes a fixing structure 7 that fixes the magnet 2 within the opening 36, as shown in FIG. 3 . The fixing structure 7 includes a first support surface 71 and a second support surface 72 that sandwich a portion of the magnet 2 in a direction along the thickness of the magnet 2. The rotor 1 includes a first member 6 that is attached to the shaft 4 so as to move in conjunction with the shaft 4. In this example, the first member 6 includes a push nut 61. In embodiment 1, a flange portion 41 is provided around the shaft 4. In embodiment 1, the first support surface 71 is part of the first member 6 and is the surface that faces the magnet 2, and the second support surface 72 is the seat surface 42 of the flange portion 41. In other words, in embodiment 1, a portion of the magnet 2 is sandwiched between the first member 6 and the flange portion 41.

[0037] <<Magnet>> The magnet 2 is a flat plate-shaped member arranged in the opening 36 provided in the support member 3. The shape of the magnet 2 may be any shape corresponding to the shape of the opening 36. The magnet 2 is arranged around the rotation shaft 5.

[0038] The rotor 1 of this example includes a plurality of magnets 2. The magnets 2 are arranged at equal intervals around the rotation shaft 5. The number of magnets 2 is the same as the number of teeth 822 that are part of the core 82 of the stator 81 shown in FIG. 4. The planar shape of each magnet 2 corresponds to the planar shape of the end face of each tooth 822. Each magnet 2 is magnetized in a direction parallel to the rotation shaft 5. The magnetization directions of adjacent magnets 2 around the rotation shaft 5 are opposite to each other. When the coil 83 of the stator 81 is excited to generate a rotating magnetic field, the rotor 1 rotates relative to the stator 81 due to the attractive or repulsive force caused by the rotating magnetic field. As the rotor 1 rotates, the end faces of each tooth 822 receive magnetic flux from the rotating magnets 2.

[0039] The rotor 1 may include one magnet 2. When the number of magnets 2 is one, the magnet 2 has a circular ring shape. In the circular ring magnet 2, the south poles and north poles are alternately arranged around the rotation axis 5.

[0040] The magnet 2 has a first surface 21, a second surface 22, an inner circumferential surface 23, and an outer circumferential surface 24. The first surface 21 and the second surface 22 are the front and back surfaces of the magnet 2. In this example, the first surface 21 and the second surface 22 each face the stator 81 shown in FIG. 4. A portion of the first surface 21 faces a first support surface 71, which will be described later. A portion of the second surface 22 faces a second support surface 72, which will be described later. A portion of the magnet 2 is sandwiched between the first support surface 71 and the second support surface 72. The inner circumferential surface 23 is the surface closer to the rotation axis 5. The outer circumferential surface 24 is the surface farther from the rotation axis 5 than the inner circumferential surface 23.

[0041] As shown in FIG. 3 , the magnet 2 has a first region 2A sandwiched between the first support surface 71 and the second support surface 72, and a second region 2B not sandwiched between the first support surface 71 and the second support surface 72. In FIG. 3 , the boundary between the first region 2A and the second region 2B is indicated by a dashed line. In this example, the first region 2A is located near the rotation axis 5, and the second region 2B is located farther from the rotation axis 5 than the first region 2A. The first region 2A includes an inner peripheral edge portion 25 of the magnet 2. The second region 2B includes an outer peripheral edge portion 26 of the magnet 2. The first region 2A does not have to be magnetized. If the first region 2A is not magnetized, it is unlikely to affect the magnetic circuit formed in the stator 81, even if the member having the first support surface 71 and the member having the second support surface 72 are made of a magnetic material. The first region 2A may be magnetized. If the first region 2A is magnetized, it has the effect of amplifying the fixing force due to the magnetic attraction effect with the flange portion 41.

[0042] In this example, the first surface 21 and the second surface 22 of the second region 2B are exposed. "Exposed" means that they do not have an artificially formed coating. The "artificially formed coating" is formed for the purpose of fixing the magnet 2 to the support member 3. This coating is, for example, a resin film that covers the magnet 2 and the support member 3 so that the magnet 2 fitted into the opening 36 is integrated with the support member 3. The "artificially formed coating" does not include natural oxide films or unavoidable surface contamination. If the first surface 21 and the second surface 22 of the second region 2B are exposed, it is easier to reduce the air gap between the end face of each tooth 822 and the magnet 2 shown in FIG. 4.

[0043] The thickness of the magnet 2 may be the same as or greater than the thickness of the support member 3. The thickness of the magnet 2 is the length parallel to the rotation axis 5 between the first surface 21 and the second surface 22 of the magnet 2. The thickness of the support member 3 is the length parallel to the rotation axis 5 between the first surface 31 and the second surface 32 of the support member 3. In this example, the thickness of the magnet 2 is slightly greater than the thickness of the support member 3, so that the second surface 22 is flush with the second surface 32 of the support member 3 and the first surface 21 slightly protrudes from the first surface 31 of the support member 3.

[0044] The magnet 2 is a permanent magnet. Specific examples of the permanent magnet include a ferrite magnet, a neodymium magnet, a samarium-cobalt magnet, and a bonded magnet. Neodymium magnets and samarium-cobalt magnets have particularly strong magnetic forces.

[0045] <<Support Member>> The support member 3 is a member that supports the magnet 2. The support member 3 may be disk-shaped. The support member 3 has a through hole 33 provided in the center of the support member 3. The main shaft portion 40 of the shaft 4 is press-fitted into this through hole 33. The support member 3 and the shaft 4 are assembled by press-fitting the main shaft portion 40 of the shaft 4 into the through hole 33. The support member 3 is rotatably supported by the shaft 4 with respect to a case 85 shown in FIG. 4 .

[0046] As shown in FIGS. 2 and 3 , the support member 3 has openings 36 in which the magnets 2 are disposed. The support member 3 of this example has a plurality of openings 36 arranged at equal intervals around the through hole 33. Each opening 36 is a through hole that opens into a first surface 31 and a second surface 32 of the support member 3. The first surface 31 and the second surface 32 are the front and back surfaces of the support member 3. Each of the first surface 31 and the second surface 32 faces the stator 81 shown in FIG. 4 . The annular region between the through hole 33 and each opening 36 in the first surface 31 faces a first support surface 71, which will be described later. The annular region between the through hole 33 and each opening 36 in the second surface 32 faces a second support surface 72, which will be described later.

[0047] Each opening 36 in this example has a peripheral surface 361 that is parallel to the rotation axis 5 between the first surface 31 and the second surface 32. The peripheral surface 361 in this example is a surface that extends perpendicular to the first surface 31 and the second surface 32.

[0048] The support member 3 is made of, for example, stainless steel. A support member 3 made of stainless steel has high strength. The support member 3 is made of, for example, a non-magnetic material such as non-magnetic stainless steel. If the support member 3 is made of a non-magnetic material, the effect of the support member 3 on the magnetic circuit is small.

[0049] As shown in FIG. 2 , the support member 3 is provided with a frame-shaped portion 34 that forms an opening 36. In this example, slits 35 are provided to divide the frame of the frame-shaped portion 34. In this example, a plurality of slits 35 are provided in the support member 3. One slit 35 is provided for each opening 36. In this example, the slits 35 are provided in the piece of the frame-shaped portion 34 that has the outer circumferential surface of the support member 3. Each slit 35 is provided so as to open in the first surface 31, the second surface 32, the outer circumferential surface, and the circumferential surface that forms the opening 36. By dividing the frame-shaped portion 34 by the slits 35, eddy currents that flow in the frame-shaped portion 34 can be divided, thereby reducing eddy current loss.

[0050] <<Shaft>> The shaft 4 has a rotation axis 5 of the rotor 1. The rotation axis 5 is also the rotation axis of the support member 3. The shaft 4 has a main shaft portion 40 that is inserted into the through hole 33 of the support member 3. The shaft 4 of this example has a flange portion 41 provided around the main shaft portion 40. The flange portion 41 of this example is provided integrally with the main shaft portion 40.

[0051] The flange portion 41 is an annular plate-shaped member that protrudes from the main shaft portion 40 in a direction along the diameter of the rotating shaft 5. The seating surface 42 of the flange portion 41 faces the magnet 2 and the support member 3. This seating surface 42 is the second support surface 72 described below. The protruding length from the outer peripheral surface of the main shaft portion 40 to the outer peripheral edge of the flange portion 41 can be appropriately selected as long as the seating surface 42 of the flange portion 41 faces the second surface 22 of the magnet 2. The seating surface 42 of the flange portion 41, together with the first support surface 71 described below, easily sandwiches a portion of the magnet 2. When the second support surface 72 is the seating surface 42 of the flange portion 41, it can easily sandwich a portion of the magnet 2 together with the first support surface 71, even if multiple magnets 2 are arranged side by side at intervals around the rotating shaft 5. By adjusting the protruding length, the range of the first region 2A of the magnet 2 sandwiched between the first support surface 71 and the second support surface 72 can be easily adjusted.

[0052] Unlike this example, the flange portion 41 may have a gear-like configuration in which a plurality of protrusions are arranged at intervals around the rotation shaft 5 so as to overlap a portion of each magnet 2 .

[0053] The thickness of flange portion 41 can be selected appropriately depending on the air gap clearance formed between the end face of each tooth 822 shown in Fig. 4 and magnet 2. The outer diameter of flange portion 41 should be set to an outer diameter that does not interfere with stator 81 shown in Fig. 4, particularly coil 83.

[0054] The shaft 4 is formed, for example, from carbon steel. A shaft 4 formed from carbon steel has high strength. A shaft 4 formed from carbon steel has excellent workability. The shaft 4 may be formed from a non-magnetic material or a magnetic material. If the shaft 4 is formed from a non-magnetic material, i.e., if the flange portion 41 is formed from a non-magnetic material, the flange portion 41 has little effect on the magnetic circuit even if the first region 2A of the magnet 2 is magnetized. If the shaft 4 is formed from a magnetic material, i.e., if the flange portion 41 is formed from a magnetic material, a magnetic attraction force acts between the magnet 2 and the flange portion 41, thereby improving the fixing strength of the magnet 2.

[0055] <<First Member>> The first member 6 is a member that is independent of the shaft 4 and can be attached to the main shaft portion 40. The first member 6 attached to the shaft 4 rotates in conjunction with the shaft 4. In other words, the first member 6 attached to the shaft 4 rotates in conjunction with the shaft 4 together with the support member 3 on which the magnet 2 is arranged.

[0056] In this example, the first member 6 includes a push nut 61 and a buffer member 62 that are inserted through the main shaft portion 40 of the shaft 4. The push nut 61 has an annular base portion and claw portions that extend from the base portion toward the center of the push nut 61. The main shaft portion 40 passes through a through hole provided in the center of the base portion. The base portion has a surface that faces the first surface 21 of the magnet 2. This surface of the base portion is the first support surface 71, which will be described later. The width of the base portion can be selected as appropriate as long as the base portion can face the first surface 21 of the magnet 2. The width of the base portion is the length between the inner and outer peripheral surfaces of the base portion. The claw portions are inclined in a direction away from the base portion as they extend from the base portion toward the center of the push nut 61. When the push nut 61 is attached to the main shaft portion 40, the claw portions are fitted onto the main shaft portion 40 so that the inner peripheral edges of the claw portions are oriented away from the support member 3 as they approach the center of the push nut 61. When push nut 61 is attached to main shaft portion 40, the inner peripheral edges of the claws bite into the outer peripheral surface of main shaft portion 40. This biting of the claws secures the push nut to main shaft portion 40. With push nut 61, simply by attaching it to shaft 4, it is possible to sandwich a portion of magnet 2 together with flange portion 41.

[0057] The push nut 61 is made of, for example, stainless steel. The push nut 61 made of stainless steel has high strength. The push nut 61 is made of, for example, a non-magnetic material such as non-magnetic stainless steel. If the push nut 61 is made of a non-magnetic material, the impact of the push nut 61 on the magnetic circuit is small.

[0058] The buffer member 62 is disposed between the push nut 61 and the magnet 2. Disposing the buffer member 62 between the push nut 61 and the magnet 2 reduces the likelihood of damage to the magnet 2 due to the pressure of the push nut 61. In this example, a step is formed between the first surface 21 of the magnet 2 and the first surface 31 of the support member 3, and the buffer member 62 absorbs this step. Absorbing this step by the buffer member 62 makes it easier to even out the surface pressure from the push nut 61. The buffer member 62 has a surface facing the first surface 21 of the magnet 2. This surface of the buffer member 62 also serves as the first support surface 71, which will be described later. A commercially available gasket, for example, can be used as the buffer member 62. The buffer member 62 is not essential. If the first member 6 does not include the buffer member 62, for example, the first surface 21 of the magnet 2 and the first surface 31 of the support member 3 are flush with each other. When the first member 6 does not include the buffer member 62 and the step is formed, for example, a protrusion that can absorb the step may be formed on the push nut 61. This protrusion is provided, for example, on the surface of the base of the push nut 61 that faces the support member 3.

[0059] The buffer member 62 is capable of pressing a portion of the magnet 2 together with the push nut 61 and is made of a material with cushioning properties. The buffer member 62 is made of, for example, a non-magnetic material. If the buffer member 62 is made of a non-magnetic material, the impact of the buffer member 62 on the magnetic circuit is small. The buffer member 62 is made of, for example, a carbon material.

[0060] In this example, the outer diameters of the push nut 61 and the buffer member 62 when attached to the main shaft portion 40 of the shaft 4 are larger than the outer diameter of the flange portion 41 of the shaft 4. The outer diameters of the push nut 61 and the buffer member 62 when attached to the main shaft portion 40 of the shaft 4 may be the same as or smaller than the outer diameter of the flange portion 41 of the shaft 4.

[0061] The first member 6 is not limited to the push nut 61 as long as it is a member that can press a part of the magnet 2. Another example of the first member 6 will be described in a sixth embodiment below.

[0062] <<Fixing Structure>> The fixing structure 7 includes a first support surface 71 and a second support surface 72 that sandwich a portion of the magnet 2 in a direction along the thickness of the magnet 2 so as to fix the magnet 2 within the opening 36. The direction along the thickness of the magnet 2 is parallel to the rotation axis 5 and is the direction from the first surface 21 to the second surface 22 of the magnet 2 or the direction from the second surface 22 to the first surface 21. The first support surface 71 is a part of the first member 6 and is a surface that faces the magnet 2. In this example, the first support surface 71 is a surface of each of the push nut 61 and the buffer member 62 that faces the first surface 21 of the magnet 2. In this example, the second support surface 72 is the bearing surface 42 of the flange portion 41 provided on the shaft 4.

[0063] The magnet 2 sandwiched between the first support surface 71 and the second support surface 72 is firmly fixed within the opening 36. Because the magnet 2 is firmly fixed within the opening 36, the magnet 2 is unlikely to come off the support member 3 even when the rotor 1 is rotated at high speed. The fixing structure 7 sandwiching the magnet 2 between the first support surface 71 and the second support surface 72 makes it unlikely for the magnet 2 to fall out of the opening 36, even if the opening 36 is a through hole. When the magnet 2 is sandwiched between the first support surface 71 and the second support surface 72, a heat transfer path is formed from the first surface 21 of the magnet 2 to the shaft 4 because the first support surface 71 is part of the first member 6 attached to the shaft 4. In this example, the second support surface 72 is the seat surface 42 of the flange portion 41 provided on the shaft 4, so a heat transfer path is also formed from the second surface 22 of the magnet 2 to the shaft 4. The rotor 1 having the above heat transfer path has excellent heat dissipation properties.

[0064] The area of ​​the region on the first surface 21 of the magnet 2 sandwiched between the first support surface 71 and the second support surface 72 is, for example, 5% to 15% of the surface area of ​​the first surface 21. In this example, because multiple magnets 2 are arranged, 5% to 15% of the surface area of ​​the first surface 21 of each magnet 2 is sandwiched between the first support surface 71 and the second support surface 72. If 5% or more of the surface area of ​​the first surface 21 is sandwiched between the first support surface 71 and the second support surface 72, the magnet 2 is more firmly fixed within the opening 36. If the area of ​​the region on the first surface 21 sandwiched between the first support surface 71 and the second support surface 72 is 15% or less of the surface area of ​​the first surface, the influence of the first member 6 and the flange portion 41 on the magnetic circuit is small. The area of ​​the region on the first surface 21 of the magnet 2 sandwiched between the first support surface 71 and the second support surface 72 may be 10% to 15% of the surface area of ​​the first surface 21.

[0065] The fixing structure 7 may include an adhesive 75 provided between the magnet 2 and the support member 3. In this example, the adhesive 75 is provided between the peripheral surface 361 forming the opening 36 and the outer peripheral surface 24 of the magnet 2. When the magnet 2 and the support member 3 are fixed with the adhesive 75, the magnet 2 is more firmly fixed within the opening 36. The adhesive 75 may soften depending on the heat resistance of the adhesive 75 or the usage environment of the rotor 1. If the magnet 2 is sandwiched between the first support surface 71 and the second support surface 72, the magnet 2 is less likely to come off the support member 3 even if the adhesive 75 softens. The fixing structure 7, which sandwiches the magnet 2 between the first support surface 71 and the second support surface 72, is less susceptible to the usage environment of the rotor 1. Therefore, the rotor 1 including the above fixing structure 7 has a higher fixing strength of the magnet 2 to the support member 3 compared to when the magnet 2 is fixed within the opening 36 only by the adhesive 75.

[0066] <Rotating Electric Machine> A rotating electric machine 8 of the first embodiment will be described with reference to FIG. 4 . FIG. 4 is a cross-sectional view of the rotating electric machine 8 taken along a plane parallel to the rotating shaft 5. The rotating electric machine 8 can be used as a motor or a generator. The rotating electric machine 8 includes the rotor 1 of the first embodiment described above and one or more stators 81. The rotating electric machine 8 shown in FIG. 4 is a single-rotor / double-stator type including one rotor 1 and two stators 81. Alternatively, the rotating electric machine may be a single-rotor / single-stator type including one rotor 1 and one stator 81, or a double-rotor / single-stator type including two rotors 1 and one stator 81. In a double-rotor / single-stator type rotating electric machine, one stator 81 is assembled so that it is sandwiched between two assemblies, each including a magnet 2 and a support member 3, along the rotating shaft 5.

[0067] Each stator 81 includes a core 82 and a coil 83. The core 82 includes a yoke 821 and a plurality of teeth 822. The yoke 821 may be disk-shaped. A through hole is provided in the center of the yoke 821. A bearing (not shown) is provided in this through hole, and the main shaft portion 40 of the shaft 4 is inserted into this bearing. The plurality of teeth 822 are arranged at equal intervals around the rotating shaft 5. Each tooth 822 is columnar. Each tooth 822 protrudes from the first surface or the second surface, which is the front or back surface of the yoke 821. The end face of each tooth 822 faces the magnet 2. The yoke 821 magnetically couples adjacent teeth 822 among the plurality of teeth 822 arranged around the rotating shaft 5. The yoke 821 and each tooth 822 are, for example, an integral powder compact. A coil 83 is arranged on each tooth 822. The coil 83 has a cylindrical portion formed by winding a wire in a spiral shape. The coil 83 is, for example, a rectangular cylindrical edgewise wound coil whose wire is a coated rectangular wire.

[0068] The rotor 1 and the stator 81 are housed in a case 85 having a cylindrical internal space. The case 85 has a cylindrical portion and two plate portions. The cylindrical portion surrounds the outer periphery of the rotor 1 and the stator 81. Plate portions are disposed on both ends of the cylindrical portion. The rotor 1 and the stator 81 are housed in the case 85 so as to be sandwiched between the two plate portions. The stator 81 is fixed to the case 85 by fitting a portion of the yoke 821 into the plate portions. A through hole is provided in the center of the plate portions. A bearing (not shown) is provided in this through hole, and the main shaft portion 40 of the shaft 4 is inserted into this bearing. The main shaft portion 40 passes through the case 85.

[0069] In a rotating electric machine 8 including the rotor 1 of embodiment 1, the magnets 2 are unlikely to come off the support members 3 even when the rotor 1 is rotated at high speed, thereby improving the output of the rotating electric machine 8. In a rotating electric machine 8 including the rotor 1 of embodiment 1, a heat transfer path is formed from the magnets 2 to the shaft 4, so the rotor 1 has excellent heat dissipation properties. When the rotor 1 has excellent heat dissipation properties, heat is unlikely to be trapped around the coils 83, and as a result, the stator 81 also has excellent heat dissipation properties. When the rotor 1 and the stator 81 each have excellent heat dissipation properties, heat is unlikely to be trapped inside the case 85, and the entire rotating electric machine 8 has excellent heat dissipation properties.

[0070] [Embodiment 2] A rotor 1 of embodiment 2 will be described with reference to Figure 5. Figure 5 is a partial cross-sectional view of the fixing structure 7 of the rotor 1 cut along a plane parallel to the rotation axis 5. The rotor 1 of embodiment 2 differs from the rotor 1 of embodiment 1 in the member having the second support surface 72. In the rotor 1 of embodiment 2, the second support surface 72 is not part of the flange portion 41 but is part of the support member 3. The rotor 1 of embodiment 2 can have the same configuration as the rotor 1 of embodiment 1, except that the second support surface 72 is part of the support member 3.

[0071] The support member 3 includes a protrusion 38 provided on at least a portion of the periphery of the opening 36 of the support member 3. In this example, the protrusion 38 is provided on the inner periphery of the periphery of the opening 36, which is located near the rotation shaft 5. The protrusion 38 protrudes from the periphery of the opening 36 so as to overlap a portion of the opening 36. In this example, the protrusion 38 is provided in an annular shape around the rotation shaft 5. In this case, the thickness of the region of the support member 3 located near the rotation shaft 5 may be thicker than that of the other region, or the overall thickness of the support member 3 may be thicker than the thickness of the support member 3 of embodiment 1. Multiple protrusions 38 may be provided at intervals around the rotation shaft 5 corresponding to each of the multiple openings 36. The region of the protrusion 38 overlapping the opening 36 faces the second surface 22 of the magnet 2. The protrusion length from the periphery of the opening 36 to the tip of the protrusion 38 can be selected as appropriate within a range that allows the magnet 2 to be supported within the opening 36. The thickness of the protrusion 38 can be appropriately selected depending on the clearance of the air gap formed between the end face of each tooth 822 shown in FIG. 4 and the magnet 2.

[0072] The second support surface 72 is the surface 39 that forms the protrusion 38. The surface 39 that forms the protrusion 38 provided on the periphery of the opening 36 easily pinches a part of the magnet 2 together with the first support surface 71. When the second support surface 72 is the surface 39 that forms the protrusion 38 provided on the periphery of the opening 36, by placing the magnet 2 in the opening 36, the second surface 22 of the magnet 2 can be easily supported by the second support surface 72.

[0073] The shaft 4 in this example does not include the flange portion 41 shown in FIG. 3 . The shaft 4 may include the flange portion 41, and the support member 3 may include the protrusion 38. The flange portion 41 is configured to support the protrusion 38. In this case, the second support surface 72 includes the seating surface 42 of the flange portion 41 and the surface 39 of the protrusion 38. A portion of the magnet 2 is sandwiched between the set of the push nut 61 and the buffer member 62 and the set of the flange portion 41 and the protrusion 38. The outer diameter of the flange portion 41 may be larger, smaller, or the same as the outer diameter of the protrusion 38. The outer diameter of the flange portion 41 is the distance from the rotation shaft 5 to the outer edge of the flange portion 41. The outer diameter of the protrusion 38 is the distance from the rotation shaft 5 to the tip of the protrusion 38. When the outer diameter of the flange portion 41 is larger than the outer diameter of the protrusion 38, the seating surface 42 of the flange portion 41 may be a flat surface, and a gap may be formed between the magnet 2 and the portion of the flange portion 41 that does not contact the protrusion 38. A thick portion that fills the gap may be provided in the portion of flange portion 41 that does not contact protrusion 38. When both flange portion 41 and protrusion 38 are provided, the total thickness of flange portion 41 and protrusion 38 may be selected appropriately depending on the air gap clearance formed between the end face of each tooth 822 shown in FIG.

[0074] [Embodiment 3] A rotor 1 of embodiment 3 will be described with reference to Figure 6. Figure 6 is a partial cross-sectional view of the fixing structure 7 of the rotor 1 cut along a plane parallel to the rotation axis 5. In the rotor 1 of embodiment 3, the second support surface 72 is part of the support member 3. The rotor 1 of embodiment 3 differs from the rotor 1 of embodiment 2 in the configuration of the second support surface 72. The rotor 1 of embodiment 3 can have the same configuration as the rotor 1 of embodiment 1, except that the second support surface 72 is part of the support member 3.

[0075] The peripheral surface 361 forming the opening 36 of the support member 3 includes an inclined surface 37. The inclined surface 37 is provided on at least a portion of the peripheral surface 361 of the opening 36 that is located near the rotation shaft 5. The inclined surfaces 37 are provided, for example, on portions of the peripheral surface 361 of the opening 36 that face each other, more specifically, on the inner peripheral surface that is located near the rotation shaft 5 and the outer peripheral surface that is distant from the rotation shaft 5. In this case, the two side surfaces connecting the inner peripheral surface and the outer peripheral surface may be inclined surfaces 37 or vertical surfaces. The entire circumference of the peripheral surface 361 may be inclined surfaces 37.

[0076] The inclined surface 37 is inclined inward of the opening 36 as it extends from the first surface 21 to the second surface 22. Therefore, the area of ​​the opening 36 facing the second surface 22 is smaller than the area of ​​the opening 36 facing the first surface 21. At least a portion of the circumferential surface of the magnet 2 is inclined to correspond to the inclined surface 37. At least the inner circumferential surface 23 of the magnet 2 includes an inclined surface. The inclination angle of the inclined surface 37 can be appropriately selected within a range that allows the magnet 2 to be supported within the opening 36. In a longitudinal cross section of the rotor 1 including the rotating shaft 5, the position of the edge formed by the inclined surface and the second surface 22 on the inner circumferential surface 23 and the position of the outer circumferential edge of the first member 6 may be the same distance from the rotating shaft 5 or may be different distances from the rotating shaft 5. If the edge formed by the inclined surface and the second surface 22 on the inner circumferential surface 23 is closer to the rotating shaft 5 than the outer circumferential edge of the first member 6, it is easier to make the thickness of the magnet 2 uniform over a wide range. If the edge formed by the inclined surface of the inner peripheral surface 23 and the second surface 22 is located farther from the rotation axis 5 than the outer peripheral edge of the first member 6, it is easy to increase the area that sandwiches the magnet 2.

[0077] The second support surface 72 is an inclined surface 37. Depending on the angle of inclination, the inclined surface 37 can also sandwich a portion of the magnet 2 together with the first support surface 71. When the second support surface 72 is an inclined surface 37, the portion forming the second support surface 72 is located inside the opening 36, so the fixing structure 7 does not become too large.

[0078] The shaft 4 of this example does not include the flange portion 41 shown in FIG. 3 . The shaft 4 may include the flange portion 41, and the support member 3 may include the inclined surface 37. When the flange portion 41 is viewed from the flange portion 41 toward the support member 3, the seating surface 42 is provided to overlap the inclined surface 37. In this case, the second support surface 72 includes the seating surface 42 of the flange portion 41 and the inclined surface 37. A portion of the magnet 2 is sandwiched between the set of the push nut 61 and the buffer member 62 and the set of the flange portion 41 and the inclined surface 37. The support member 3 of this example does not include the protrusion 38 shown in FIG. 5 . The support member 3 may include the protrusion 38 and the inclined surface 37. In this case, in a vertical cross section of the rotor 1 including the rotating shaft 5, the corner formed by the surface 39 of the protrusion 38 and the inclined surface 37 may be closer to the rotating shaft 5 than the outer circumferential edge of the first member 6, and the distance from the rotating shaft 5 between the tip of the protrusion 38 and the outer circumferential edge of the first member 6 may be the same. The position of the tip of the protrusion 38 and the position of the outer circumferential edge of the first member 6 may be at different distances from the rotation axis 5. The shaft 4 may include a flange portion 41, and the support member 3 may include the protrusion 38 and the inclined surface 37.

[0079] [Embodiment 4] Although not shown, the rotor may include a second member attached to the shaft so as to move in conjunction with the shaft. The second member has a configuration similar to that of the first member 6 shown in Figures 1 to 3. The second member includes, for example, a push nut. The second member may include a push nut and a buffer member. The second member is arranged so as to sandwich a portion of the magnet 2 together with the first member 6. The second support surface is a surface of the second member that faces the second surface of the magnet.

[0080] [Embodiment 5] Although not shown, the opening provided in the support member may be a recessed portion with a bottom. In this case, the second surface and the peripheral surface of the magnet face the surface forming the opening, and the first surface is exposed through the opening. The second support surface is the bottom surface forming the opening. In this example, the entire second surface of the magnet faces the second support surface. A portion of the first surface of the magnet faces the first support surface. Therefore, in this example, a portion of the magnet is sandwiched between the first support surface and the second support surface. The rotor of this example is used in a rotating electric machine of a single rotor / single stator type having one rotor and one stator, or a double rotor / single stator type having two rotors and one stator.

[0081] [Embodiment 6] Although not shown, the first member may be a threaded holding member instead of the push nut shown in Figures 1 to 6. The threaded holding member is, for example, a member equipped with a nut having a female thread, specifically a flange nut. In this case, the main shaft portion of the shaft has a male thread provided on its circumferential surface. This male thread is threadedly coupled to the female thread. The second member in embodiment 4 may also be a threaded holding member. If both the first member and the second member are, for example, flange nuts, a portion of the magnet is sandwiched between the two flange nuts.

[0082] Test Example 1 In test example 1, a rotor according to the first embodiment, which includes a fixing structure, and a conventional rotor, which does not include a fixing structure, were fabricated, and the fixing strength of the magnet to the support member in each rotor was measured.

[0083] <Description of Test Specimen> Test Specimen A is a conventional rotor without a fixed structure. The rotor of Test Specimen A comprises a plurality of magnets, a support member, and a shaft. The support member has a plurality of openings penetrating the first and second surfaces, spaced equally around the rotation axis. The circumferential surface of each opening is a surface extending perpendicular to the first and second surfaces. Each magnet is fixed to the circumferential surface of each opening with an adhesive. The adhesive is an epoxy resin. This adhesive has a heat resistance of 100°C or higher. The support member and shaft of Test Specimen A do not have a surface facing the second surface of the magnet. Furthermore, the magnet of Test Specimen A has the entire first and second surfaces exposed.

[0084] Specimen B is the rotor 1 shown in Figures 1 to 3. The rotor of specimen B further includes a first member and a fixed structure compared to the rotor of specimen A. The first member is a push nut and a buffer member. The push nut and the buffer member have surfaces facing the first surface of the magnet. The surfaces of the push nut and the buffer member facing the first surface of the magnet are the first support surface of the fixed structure. The shaft is provided with a flange portion having a seat surface facing the second surface of the magnet. The seat surface of the flange portion is the second support surface of the fixed structure. A portion of the magnet is sandwiched between the first support surface and the second support surface. The magnet of specimen B has a first region sandwiched between the first support surface and the second support surface, and a second region not sandwiched between the first support surface and the second support surface. The first and second surfaces of the second region are exposed. The area of ​​the region sandwiched between the first support surface and the second support surface on the first surface of each magnet is 5% or more of the surface area of ​​the first surface of each magnet.

[0085] <Fixing Strength> A surface pressure test was conducted on Test Specimen A and Test Specimen B using an autograph. In the surface pressure test, a small indenter, 1 mm inward from the periphery forming the outline of the first surface of the magnet and similar in shape to the first surface of the magnet, was used to apply uniform surface pressure to the magnet. The position where the indenter contacted the first surface of the magnet was set as the zero point, and a load was applied from that zero point at a stroke rate of 1 mm / min. The maximum load was measured from the time the load was applied until the indenter was stroked 2 mm from the zero point. The surface pressure test was conducted with the rotor maintained at a temperature of 20°C, 80°C, or 120°C. In Table 1, the maximum load of Test Specimen A at each temperature is set to 1, and the maximum load of Test Specimen B is shown as a ratio to the maximum load of Test Specimen B.

[0086]

[0087] As shown in Table 1, at 20°C, the maximum load of test specimen A and test specimen B is the same, but as the temperature increases, the maximum load of test specimen B becomes larger than that of test specimen A. At 20°C, even test specimen A, which does not have a fixing structure, has the magnet fixed to the support member with adhesive, so it is thought to have the same fixing strength as test specimen B, which has a fixing structure. At temperatures above 80°C, it is thought that the adhesive in test specimen A, which does not have a fixing structure, softens, making the magnet more likely to come off the support member. In test specimen B, which has a fixing structure, the magnet is sandwiched between the first support surface and the second support surface, so it can be said to have high fixing strength regardless of temperature.

[0088] [Test Example 2] In Test Example 2, a single-rotor, single-stator type rotating electric machine was fabricated using the test specimen described in Test Example 1, and the temperatures of the magnet, coil, core, and case were measured when the rotor was rotated. The core was an integrated powder compact comprising a disk-shaped yoke and multiple columnar teeth. The case was made of aluminum. A coil was disposed on each tooth. The rotor rotation speed was 30,000 rpm. The input current to the coil was 18.1 Apeak, and the current density was 8.31 Arms / mm ２The output of the rotating electric machine was 300 W. Table 2 shows the average temperatures of the respective members of the rotating electric machine using test specimen A and the average temperatures of the respective members of the rotating electric machine using test specimen B.

[0089]

[0090] As shown in Table 2, the temperatures of the magnet, coil, core, and case of Test Specimen B were all lower than those of Test Specimen A. In Test Specimen B, which has a fixed structure, the magnet is sandwiched between the first and second support surfaces, which creates a heat transfer path from the magnet to the shaft, and it is believed that this heat transfer path improved the heat dissipation of the magnet. The improved heat dissipation of the magnet made it less likely for heat to build up around the coil, and as a result, it is believed that the heat dissipation of the coil, core, and case also improved.

[0091] REFERENCE SIGNS LIST 1 rotor 2 magnet 21 first surface, 22 second surface, 23 inner circumferential surface, 24 outer circumferential surface 25 inner circumferential edge portion, 26 outer circumferential edge portion 2A first region, 2B second region 3 support member 31 first surface, 32 second surface 33 through hole, 34 frame-shaped portion, 35 slit 36 ​​opening, 361 circumferential surface 37 inclined surface, 38 protrusion, 39 surface 4 shaft 40 main shaft portion, 41 flange portion, 42 seat surface 5 rotating shaft 6 first member, 61 push nut, 62 cushioning member 7 fixing structure 71 first support surface, 72 second support surface, 75 adhesive 8 rotating electric machine 81 stator, 82 core, 821 yoke, 822 teeth 83 coil, 85 case

Claims

1. A rotor for use in an axial gap type rotating electric machine, comprising: a flat magnet; a support member having an opening in which the magnet is placed; a shaft having the same rotation axis as the support member; a first member attached to the shaft; and a fixing structure for fixing the magnet within the opening, wherein the fixing structure has a first support surface and a second support surface that sandwich a portion of the magnet in a direction along the thickness of the magnet, and the first support surface is a part of the first member and faces the magnet.

2. A rotor as set forth in claim 1, wherein the magnet has a first surface that faces at least a portion of the first support surface, and the area of ​​the region of the first surface sandwiched between the first support surface and the second support surface is between 5% and 15% of the surface area of ​​the first surface.

3. A rotor according to claim 1 or claim 2, wherein the support member has a first surface and a second surface that are opposite surfaces, and the opening penetrates between the first surface and the second surface of the support member.

4. A rotor according to any one of claims 1 to 3, wherein the second support surface includes a seat surface of a flange portion provided around the shaft.

5. A rotor according to any one of claims 1 to 4, wherein the second support surface includes a surface forming a protrusion provided on at least a portion of the periphery of the opening.

6. A rotor according to any one of claims 1 to 5, wherein the peripheral surface forming the opening includes an inclined surface, and the second support surface includes the inclined surface.

7. A rotor according to any one of claims 1 to 6, wherein the first member includes a push nut that is inserted through the shaft.

8. The rotor according to claim 7, wherein said first member includes a buffer member disposed between said push nut and said magnet.

9. A rotor according to any one of claims 1 to 8, wherein the first member is made of a non-magnetic material.

10. A rotor according to any one of claims 1 to 9, wherein the region of the magnet sandwiched between the first support surface and the second support surface is not magnetized.

11. A rotor according to any one of claims 1 to 10, wherein the fixing structure comprises an adhesive provided between the magnet and the support member.

12. A rotating electric machine comprising: a rotor according to any one of claims 1 to 11; and one or more stators.

Images