Rotor and manufacturing method of rotor

Abstract

To suppress decrease in preload generated between a magnet and an armor ring when a rotor performs a rotational movement.SOLUTION: A rotor 1 comprises: a magnet 2; an inner armor ring 4, which has a cylindrical shape, contacts the magnet 2, and is formed from a metallic material; and an outer armor ring 5, which has a cylindrical shape, contacts the inner armor ring 4, and is formed from a non-metallic material. The outer armor ring 5 is more difficult to deform than the inner armor ring 4, when the magnet 2, the inner armor ring 4, and the outer armor ring 5 perform a rotational movement in unity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotor and a method for manufacturing a rotor. [Background technology]

[0002] Patent Documents 1 to 3 disclose rotor-related technologies. For example, Patent Document 1 describes a rotor including a rotor core, magnets surrounding the outer periphery of the rotor core, and a covering member surrounding the outer periphery of the magnet. The covering member is composed of a magnetic portion and a non-magnetic portion covering the magnetic portion. Patent Document 2 discloses a rotor including cylindrical magnets and an iron member disposed between the magnets, and a rotor including cylindrical magnets and a ring covering the outer periphery of the magnet. Patent Document 3 shows a cross section of a rotor. This rotor includes a rotor carrier and a cylindrical magnet unit disposed on the inner periphery of the rotor carrier. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-52466 [Patent Document 2] Patent No. 4704883 [Patent Document 3] Japanese Patent Publication No. 2021-19379 Summary of the Invention [Problem to be solved by the invention]

[0004] The interaction between the magnetic field of the magnet and the magnetic field of the coil generates a torque in the magnet. This torque is transmitted to the shaft, causing it to rotate. Torque is transmitted from the magnet to the shaft by a ring-shaped armature that contacts the magnet. Torque transmission from the magnet to the armature is affected by the frictional force acting between the magnet and the armature. To ensure the frictional force required for torque transmission, it is necessary to ensure a preload is generated between the magnet and the armature.

[0005] However, when a rotor composed of the magnet and the armature rotates, centrifugal force acts on the magnet and the armature according to the rotation speed. This centrifugal force can cause the preload generated between the magnet and the armature when the rotor is rotating to be smaller than the preload generated between the magnet and the armature when the rotor is not rotating. The reduction in the preload generated between the magnet and the armature affects the transmission of torque from the magnet to the armature and ultimately to the shaft.

[0006] Therefore, the present invention provides a rotor and a method for manufacturing the rotor that can suppress a decrease in preload that occurs between the magnet and the armature when the rotor rotates. [Means for solving the problem]

[0007] A rotor according to one embodiment of the present invention includes a magnet, a cylindrical first armor including a ring portion in contact with the magnet and made of a metallic material, and a cylindrical second armor in contact with the first armor and made of a non-metallic material. When the magnet, the first armor, and the second armor rotate together, the second armor is less likely to deform than the first armor.

[0008] When this rotor is rotating, the second armor, which is subjected to centrifugal force, is less likely to deform than the first armor, which is subjected to centrifugal force. As a result, deformation of the first armor that occurs during operation is suppressed by the second armor, and therefore, a decrease in the pressure applied to the magnet by the first armor can be suppressed.

[0009] In the rotor described above, the elastic modulus of the non-metallic material forming the second armor may be greater than the elastic modulus of the metallic material forming the first armor. With this configuration, the amount of deformation of the second armor caused by centrifugal force is smaller than the amount of deformation of the first armor caused by centrifugal force. As a result, the deformation of the first armor caused by centrifugal force is suppressed by the second armor, thereby suppressing a decrease in the preload applied by the first armor to the magnet.

[0010] In the above rotor, the linear expansion coefficient of the non-metallic material forming the second armor may be smaller than the linear expansion coefficient of the metallic material forming the first armor. With this configuration, the amount of deformation of the second armor caused by heat generated in the magnet and armor during rotation of the rotor is smaller than the amount of deformation of the first armor caused by heat generated in the magnet and armor. As a result, deformation of the first armor caused by heat generated in the magnet and armor is suppressed by the second armor, thereby suppressing a decrease in the pressure applied to the magnet by the first armor.

[0011] The inner diameter of the first armor of the rotor may be smaller than the diameter of a circumscribing circle defined by the outer peripheral surfaces of the magnets, the inner diameter of the second armor may be smaller than the outer diameter of the first armor, and the difference between the inner diameter of the first armor and the diameter of the circumscribing circle defined by the outer shapes of the magnets may be larger than the difference between the inner diameter of the second armor and the outer diameter of the first armor. This configuration also makes it possible to suppress a decrease in the preload applied to the magnets by the first armor.

[0012] The second armor of the rotor may be made of a non-metallic material, such as carbon fiber reinforced plastic. This configuration makes it possible to realize a configuration in which the second armor is less likely to deform than the first armor when the rotor rotates.

[0013] Another embodiment of the present invention is a rotor manufacturing method that includes the steps of: combining a first armor, which includes a cylindrical ring portion and is made of a metallic material, with a magnet while leaving a gap by heating the first armor or cooling the magnet; and press-fitting a second armor, which is cylindrical and made of a non-metallic material, into the first armor combined with the magnet without heating the second armor. This manufacturing method makes it possible to manufacture a rotor in which the second armor, which is subjected to centrifugal force during rotation, is less likely to deform than the first armor, which is subjected to centrifugal force. [Effects of the Invention]

[0014] According to the rotor of the present invention, it is possible to suppress the reduction in preload that occurs between the magnet and the armature when the rotor rotates, and according to the rotor manufacturing method, it is possible to manufacture a rotor that can suppress the reduction in preload that occurs between the magnet and the armature when the rotor rotates. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing the structure of a motor having a rotor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the rotor shown in FIG. [Figure 3] 3(a), 3(b), and 3(c) are diagrams for explaining the main steps of the rotor manufacturing method. [Figure 4] 4(a), 4(b), and 4(c) are diagrams for explaining the main steps of the rotor manufacturing method. [Figure 5] FIG. 5 is a perspective view showing the structure of a rotor according to a first modified example. [Figure 6] FIG. 6 is a front view of a cross section of the rotor structure of the second modified example. [Figure 7] FIG. 7 is a cross-sectional view of a rotor according to a modified example. [Figure 8] FIG. 8 is a cross-sectional view of a rotor of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0017] <Rotor> FIG. 1 shows a motor 100 having a rotor 1 according to an embodiment. FIG. 2 is a cross-sectional view of the rotor 1 taken along an imaginary plane 100S. The motor 100 can be used in a variety of systems; for example, the motor 100 may be used in an electric supercharger. The motor 100 has a stator 7 and a rotor 1. The stator 7 has a plurality of coils to which a three-phase alternating current is applied. The rotor 1 has a magnet. A torque is generated in the magnet due to the interaction between a rotating magnetic field caused by the three-phase alternating current and a magnetic field caused by the magnet. The rotor 1 has a magnet 2, a shaft 3, an inner armoring 4 (first armoring), and an outer armoring 5 (second armoring).

[0018] Magnet 2 generates a predetermined magnetic field. Magnet 2 shown in FIG. 1 has a cylindrical shape. Magnet 2 does not include a through-hole extending from one end face to the other end face. Therefore, magnet 2 can also be said to be solid. Magnet 2 has a magnet outer circumferential surface 2a and a magnet end face 2c.

[0019] The shaft 3 transmits the torque acting on the magnet 2 to an external mechanism. The shaft 3 receives the torque from the magnet 2 via the inner armoring 4. The central axis of the shaft 3 coincides with the central axis of the magnet 2. Note that the shaft 3 may also receive the torque directly from the magnet 2. The shaft 3 has a shaft portion 31 and a flange portion 32.

[0020] The shaft portion 31 may be rotatably supported by a bearing or the like. When the motor 100 is incorporated into an electric supercharger, an impeller may be attached to the end of the shaft portion 31. The shaft portion 31 protrudes from the inner armor ring 4 and the outer armor ring 5. In the example shown in FIG. 1 , the diameter of the shaft portion 31 is smaller than the diameter of the magnet 2. Note that the diameter of the shaft portion 31 may be the same as the diameter of the magnet 2.

[0021] The flange portion 32 is provided at the other end of the shaft portion 31. The flange portion 32 protrudes in the diameter direction relative to the shaft portion 31. The diameter of the flange portion 32 is larger than the diameter of the shaft portion 31. The diameter of the flange portion 32 may be approximately the same as the diameter of the magnet 2. The flange portion 32 has a predetermined thickness. The flange portion 32 has a flange outer peripheral surface 32a and a flange end surface 32c.

[0022] A portion or the entire surface of the flange outer peripheral surface 32a is in contact with the inner armor 4. In other words, the flange portion 32 is inserted into the inner armor 4. The relationship between the outer diameter of the flange portion 32 and the inner diameter of the inner armor 4 is what is called an interference fit. More specifically, the outer diameter of the flange portion 32 is slightly larger than the inner diameter of the inner armor 4. As a result, the flange portion 32 is pressed by the inner armor 4 with a predetermined force.

[0023] The flange end face 32c is in contact with the magnet end face 2c. As mentioned above, the diameter of the flange portion 32 is approximately the same as the diameter of the magnet 2, so the entire surface of the flange end face 32c is in contact with the entire surface of the magnet end face 2c. The flange end face 32c may simply be in contact with the magnet end face 2c. The flange end face 32c may also be fixed to the magnet end face 2c with an adhesive or the like.

[0024] When the rotor 1 rotates, the shaft 3 and the inner armoring 4 are subjected to centrifugal force according to their mass, rotation speed, and distance from the center of rotation. Whether centrifugal force is not acting (stopped state) or centrifugal force is acting (operating state), the flange portion 32 is always subjected to force from the inner armoring 4.

[0025] The centrifugal force described above also acts on the magnet 2. The magnitude of the centrifugal force increases as the rotation speed increases. The inner armour ring 4 prevents the magnet 2 from cracking due to this centrifugal force. The inner armour ring 4 is cylindrical in shape. The magnet 2 and flange portion 32 are arranged inside the inner armour ring 4. The inner armour ring 4 has an inner armour ring outer peripheral surface 4a, an inner armour ring inner peripheral surface 4b, and an inner armour ring end surface 4c.

[0026] The inner armour outer peripheral surface 4a contacts the outer armour 5. The inner armour outer peripheral surface 4a corresponds to the circumscribing circle defined by the outer shape of the magnet. The diameter of the inner armour outer peripheral surface 4a corresponds to the diameter of the circumscribing circle defined by the outer shape of the magnet. The inner armour inner peripheral surface 4b contacts the magnet outer peripheral surface 2a and the flange outer peripheral surface 32a. The inner armour end surface 4c is an exposed surface. The rotor 1 may be provided with end rings as necessary. If end rings are provided, the outer armour end surface 5c may contact the end rings.

[0027] The inner armor 4 is made of a metal material. Examples of metal materials that can be used to form the inner armor 4 include nickel alloys and titanium alloys. The inner armor 4 made of a metal material exhibits ease of deformation based on the physical properties of the metal material. Specifically, the ease of deformation of the inner armor 4 is indicated by the elastic modulus, which indicates the degree of deformation in response to force, and the linear expansion coefficient, which indicates the degree of expansion or contraction in response to temperature.

[0028] For example, the linear expansion coefficient of metal materials is relatively large.-7 [1 / °C] or more. By utilizing the characteristics of such a large linear expansion coefficient, the inner armoring 4 can be assembled using the "shrink fit" method described below.

[0029] The inner armouring 4 is also deformed by centrifugal force. The outer armouring 5 suppresses deformation of the inner armouring 4 due to this centrifugal force. The outer armouring 5 has a cylindrical shape, just like the inner armouring 4. The inner armouring 4, magnet 2 and flange portion 32 are arranged inside the outer armouring 5. The outer armouring 5 has an outer armouring outer peripheral surface 5a, an outer armouring inner peripheral surface 5b and an outer armouring end surface 5c.

[0030] The inner peripheral surface 5b of the outer armour is in contact with the outer peripheral surface 4a of the inner armour. The outer armour end surface 5c is also an exposed surface, similar to the inner armour end surface 4c. If the rotor 1 is equipped with an end ring, the inner armour end surface 4c may be in contact with the end ring.

[0031] The outer armoring 5 is made of a non-metallic material. An example of a non-metallic material that can be used to form the outer armoring 5 is a resin material containing fibers. For example, an example of a non-metallic material is carbon fiber reinforced plastics (CFRP). The outer armoring 5 made of a non-metallic material also exhibits deformability based on the physical properties of the non-metallic material. Specifically, the deformability of the outer armoring 5 is indicated by the elastic modulus, which indicates the degree of deformation in response to force, and the linear expansion coefficient, which indicates the degree of expansion or contraction in response to temperature. For example, the linear expansion coefficient of a non-metallic material is very small. Furthermore, the linear expansion coefficient of a non-metallic material can also be negative. Due to the characteristics of such a large linear expansion coefficient, the outer armoring 5 cannot be assembled using the "shrink fitting" process described below.

[0032] <Rotor manufacturing method> A manufacturing method of the rotor 1 will be described with reference to Figures 3 and 4. First, the inner armour 4 is prepared. Then, the inner armour 4 is heated to a predetermined temperature (step S1: see Figure 3(a)). In Figure 3(a) and other figures, the inner armour 4 surrounded by a rectangle with the reference symbol 4S indicates that it has been heated to the predetermined temperature. Next, the magnet 2 is prepared. Then, the magnet 2 is inserted into the heated inner armour 4 (step S2: see Figure 3(b)). Next, the shaft 3 is prepared. Then, the shaft 3 is inserted into the heated inner armour 4 from both ends of the inner armour 4 (step S3: see Figure 3(c)).

[0033] During the operation (S2) of inserting the magnet 2 and the operation (S3) of inserting the shaft 3, the temperature of the inner armor 4 is maintained above a predetermined temperature. Because the inner armor 4 is maintained at a high temperature, the inner armor 4 maintains an expanded state. As a result, the inner diameter of the inner armor 4 becomes slightly larger. Then, by applying a force F to the magnet 2 and the shaft 3, they can be easily inserted into the inner armor 4.

[0034] After the operation of inserting the magnet 2 (S2) and the operation of inserting the shaft 3 (S3) are completed, the inner armor 4 is cooled to room temperature. As a result, the diameter of the inner armor 4 becomes smaller (it contracts), and the inner armor 4 enters a state in which it presses the shaft 3 and magnet 2 with a predetermined force. The predetermined force that the inner armor 4 applies to the shaft 3 and magnet 2 may also be referred to as pre-pressure. The state in which the inner armor 4 presses the shaft 3 and magnet 2 with a predetermined force may also be referred to as a state in which pre-pressure is generated.

[0035] This pre-pressure occurs because the inner diameter of the inner armour ring 4 is smaller than the outer diameter of the magnet 2. The dimensional difference between the inner diameter of the inner armour ring 4 and the outer diameter of the magnet 2 is called the "interference." A magnitude relationship is explicitly set for this dimensional difference in the design. In other words, the design drawings show the inner diameter of the inner armour ring 4 to be smaller than the outer dimension of the magnet 2. This magnitude relationship is set so that the inner diameter of the inner armour ring 4 is smaller than the outer diameter of the magnet 2, even if the inner diameter of the inner armour ring 4 after processing is the maximum allowable value and the outer diameter of the magnet 2 after processing is the minimum allowable value. The dimensional difference between the inner diameter of the inner armour ring 4 and the outer diameter of the magnet 2 is larger than the dimensional difference between the inner diameter of the outer armour ring 5 and the outer diameter of the inner armour ring 4. Because this dimensional difference (interference) is large, the magnet 2 cannot be pressed into the inner armour ring 4. Therefore, the inner armor ring 4 is heated to expand it, temporarily reducing or eliminating the dimensional difference, and then the magnet 2 is pushed into the inner armor ring 4.

[0036] The above series of assembly operations is called shrink fitting, which includes heating the inner armor ring 4 to slightly expand it, placing the magnet 2 and the shaft 3 in the expanded inner armor ring 4, and then cooling the inner armor ring 4 to approximately room temperature.

[0037] As a result of carrying out the above steps S1, S2 and S3, an intermediate product 1S composed of the magnet 2, two shafts 3 and inner armoring 4 is obtained (S4: see FIG. 4(a)).

[0038] The series of steps for obtaining the intermediate product 1S is not limited to the above, and various assembly steps that can result in the intermediate product 1S may be adopted and combined.

[0039] Next, the outer armoring 5 is prepared. Then, the intermediate product 1S in which the shaft 3, the magnet 2, and the inner armoring 4 are integrated is pressed against the outer armoring 5 by applying a force F (S5: see FIG. 4(b)).

[0040] When the magnet 2 and shaft 3 are pressed into the inner armoring 4, the inner armoring 4 is heated as described above. In contrast, when the intermediate product 1S is pressed into the outer armoring 5, the outer armoring 5 is not heated. In other words, the intermediate product 1S presses into the outer armoring 5 without expanding like the inner armoring 4. This pressing operation is performed by applying a force F to the intermediate product 1S in a direction along the rotation axis. This type of assembly operation is called press fitting.

[0041] The outer diameter of the outer armoring 5 is slightly smaller than the inner diameter of the inner armoring 4. In other words, an interference is also set between the outer diameter of the outer armoring 5 and the inner diameter of the inner armoring 4. As described above, the interference set between the outer diameter of the outer armoring 5 and the inner diameter of the inner armoring 4 is smaller than the interference set between the outer diameter of the magnet 2 and the inner diameter of the inner armoring 4. The interference set between the outer diameter of the outer armoring 5 and the inner diameter of the inner armoring 4 is set to an extent that allows the intermediate product 1S to be pressed into the outer armoring 5 without causing the outer armoring 5 to expand.

[0042] By carrying out the above steps S1 to S5, the rotor 1 can be obtained (S6: see FIG. 4(c)).

[0043] <Action and effect> First, the relationship between the inner armouring 4 and the outer armouring 5 will be explained in comparison with a rotor of a comparative example.

[0044] FIG. 8 is a cross-sectional view of a rotor 9 of a comparative example. The rotor 9 of the comparative example has a shaft 91, a magnet 92, and an armature 93. While the rotor 1 of this embodiment has an inner armature 4 and an outer armature 5, the rotor 9 of the comparative example has only one armature 93. The armature 93 is formed of a metallic material or a non-metallic material. Examples of metallic materials include nickel alloys and titanium alloys. Examples of non-metallic materials include carbon fiber reinforced plastics.

[0045] If the armouring 93 is made of a metal material, shrink fitting can be used, as in the manufacturing method of this embodiment. By using shrink fitting, it is possible to ensure a large interference between the magnet 92 and the armouring 93. If the armouring 93 is made of a metal material, it is not possible to impart to the rotor 1 the properties of an armouring made of a non-metallic material.

[0046] If the armor ring 93 is made of a non-metallic material, shrink fitting cannot be used, as in the manufacturing method of this embodiment. As a result, the desired interference cannot be secured between the magnet 2 and the armor ring 93. Since the desired interference cannot be secured, the desired pressurization cannot be secured.

[0047] In the rotor 1 of this embodiment, shrink fitting (S2, S3) can be used to arrange the magnets 2 and shaft 3 in the inner armoring 4 because the inner armoring 4 is made of a metallic material. Because the magnets 2 already receive most of the preload from the inner armoring 4, the amount of preload required from the outer armoring 5 can be reduced. In other words, because the interference of the outer armoring 5 can be reduced, assembly by press-fitting the outer armoring 5 is easy. This makes it possible to both ensure the desired preload and impart the properties of the outer armoring 5 made of a non-metallic material.

[0048] Here, the pressurization in the rotor 1 of the embodiment will be described in more detail.

[0049] <Elastic modulus> When the rotor 1 rotates, centrifugal forces depending on the rotation speed (angular velocity), mass, and radial dimensions act on each of the magnets 2, inner armoring 4, and outer armoring 5. In response to this centrifugal force, each of the magnets 2, inner armoring 4, and outer armoring 5 deforms depending on its elastic modulus. The elastic modulus referred to in this embodiment is, more strictly speaking, Young's modulus.

[0050] Here, we will consider centrifugal force under the following assumptions. -The mass of inner armor ring 4 (m4) is greater than the mass of outer armor ring 5 (m5) (m4>>m5). The radius (r4) of the inner armor ring 4 is almost the same as the radius (r5) of the outer armor ring 5 (r4 ≒ r5). If the rotation speed is (ω), the relationship between the centrifugal force acting on the inner armor ring 4 and the centrifugal force acting on the outer armor ring 5 is as follows: m4×r4×ω 2 >m 5 ×r 5 ×ω 2

[0051] According to the above considerations, the difference between the centrifugal force acting on the inner armouring 4 and the centrifugal force acting on the outer armouring 5 is based on the difference between the densities of the inner armouring 4 and the outer armouring 5 .

[0052] The inner armoring 4 is made of a nickel alloy, which is a metallic material. The outer armoring 5 is made of a carbon fiber reinforced plastic, which is a non-metallic material. If there is no significant difference between the thickness of the inner armoring 4 and the thickness of the outer armoring 5, the mass of the outer armoring 5 is smaller than the mass of the inner armoring 4. In other words, the centrifugal force acting on the outer armoring 5 is smaller than the centrifugal force acting on the inner armoring 4.

[0053] The elastic modulus of the outer armoring 5 is greater than the elastic modulus of the inner armoring 4 .

[0054] Therefore, the amount of deformation of the outer armoring 5, which is subjected to a relatively small centrifugal force and has a relatively large elastic modulus, is smaller than the amount of deformation of the inner armoring 4, which is subjected to a relatively large centrifugal force and has a relatively small elastic modulus. In other words, when the rotor 1 is rotating, a state occurs in which the outer armoring 5 suppresses the deformation of the inner armoring 4 that attempts to expand in the radial direction. When the deformation of the inner armoring 4 that attempts to expand in the radial direction is suppressed, the preload applied by the inner armoring 4 to the magnet 2 does not decrease. Furthermore, considering that centrifugal force also acts on the magnet 2, it is possible that the preload applied by the inner armoring 4 to the magnet 2 by the inner armoring 4 when the rotor 1 is rotating may be greater than the preload applied by the inner armoring 4 to the magnet 2 when the rotor 1 is stopped.

[0055] In other words, the degree of deformation that occurs during operation is smaller in the outer armouring 5 than in the inner armouring 4. As a result, the deformation of the inner armouring 4 is suppressed by the outer armouring 5. As a result, the preload between the outer armouring 5 and the inner armouring 4 tends to be higher compared to when the rotor is stopped. As a result, the preload between the inner armouring 4 and the magnet 2 also tends to increase or not decrease compared to when the rotor is stopped. In this way, the rotor 1 of the embodiment has the effect of being able to ensure the same or higher preload during operation as when the rotor is stopped.

[0056] If a greater preload can be secured during operation than when stopped, the interference set between the magnet 2 and the inner armoring 4 can be reduced. If the preload is greater during operation than when stopped, the preload required when rotation is stopped (during assembly) can be determined by subtracting the preload increase during operation from the preload required during operation. In other words, the preload required when rotation is stopped (during assembly) can be reduced by the amount of the preload increase during operation. As a result, the interference can be set to a medium size.

[0057] <Linear expansion coefficient> The effect of ensuring pressurization during operation can also be explained from another perspective. During operation, the magnet 2 and inner armour 4 generate heat. The heat generated by the magnet 2 and inner armour 4 causes the inner armour 4 and outer armour 5 to deform. Here, the amount of deformation of the outer armour 5 caused by heat is compared with the amount of deformation of the inner armour 4 caused by heat. The amount of deformation of the outer armour 5 made of a non-metallic material (e.g., CFRP) is smaller than the amount of deformation of the inner armour 4 made of a metallic material (e.g., nickel alloy). In other words, even from the perspective of thermal expansion, the deformation of the inner armour 4 that occurs during operation is suppressed by the outer armour 5.

[0058] In short, the rotor 1 of the embodiment includes a magnet 2, a cylindrical inner armour 4 that is in contact with the magnet 2 and is made of a metallic material, and a cylindrical outer armour 5 that is in contact with the inner armour 4 and is made of a non-metallic material. When the magnet 2, inner armour 4 and outer armour 5 rotate together, the outer armour 5 is less likely to deform than the inner armour 4.

[0059] When the rotor 1 is in rotational operation, the outer armour 5, on which centrifugal force acts, is less likely to deform than the inner armour 4, on which centrifugal force acts. As a result, deformation of the inner armour 4 that occurs during operation is suppressed by the outer armour 5, and therefore a decrease in the pressure that the inner armour 4 applies to the magnet 2 can be suppressed.

[0060] The elastic modulus of the non-metallic material forming the outer armoring 5 is greater than the elastic modulus of the metallic material forming the inner armoring 4. With this configuration, the amount of deformation of the outer armoring 5 caused by centrifugal force is smaller than the amount of deformation of the inner armoring 4 caused by centrifugal force. As a result, the deformation of the inner armoring 4 caused by centrifugal force is suppressed by the outer armoring 5, and therefore, a decrease in the preload applied by the inner armoring 4 to the magnet 2 can be suppressed.

[0061] The linear expansion coefficient of the non-metallic material forming the outer armoring 5 is smaller than the linear expansion coefficient of the metallic material forming the inner armoring 4. According to this configuration, the amount of deformation of the outer armoring 5 when it is at a high temperature is smaller than the amount of deformation of the inner armoring 4. As a result, deformation of the inner armoring 4 when it is at a high temperature is suppressed by the outer armoring 5, and therefore a decrease in the pressure applied by the inner armoring 4 to the magnet 2 can be suppressed.

[0062] The inner diameter of the inner armour ring 4 is smaller than the magnet outer peripheral surface 2a. The inner diameter of the outer armour ring 5 is smaller than the outer diameter of the inner armour ring 4. The difference between the inner diameter of the inner armour ring 4 and the outer diameter of the magnet outer peripheral surface 2a is larger than the difference between the inner diameter of the outer armour ring 5 and the outer diameter of the inner armour ring 4. This configuration also makes it possible to suppress a decrease in the pressure applied by the inner armour ring 4 to the magnet 2.

[0063] The outer armoring 5 is made of carbon fiber reinforced plastic, which is a non-metallic material. With this configuration, it is possible to realize a configuration in which the outer armoring 5 is less likely to deform than the inner armoring 4 when the rotor 1 performs rotational operation.

[0064] The manufacturing method of the rotor 1 includes step S2 of combining the inner armour 4, which includes a cylindrical ring portion and is made of a metallic material, with the magnet 2 while leaving a gap by heating the inner armour 4, and step S5 of press-fitting, without heating the outer armour 5, the cylindrical outer armour 5, which is made of a non-metallic material, into the inner armour 4 that has been combined with the magnet 2. This manufacturing method makes it possible to manufacture a rotor 1 in which the outer armour 5, which is subjected to centrifugal force, is less likely to deform than the inner armour 4, which is subjected to centrifugal force, during rotation.

[0065] <Modification> The present invention can be implemented in various forms, including the above-described embodiment, with various modifications and improvements based on the knowledge of those skilled in the art. Furthermore, it is also possible to configure modified examples by utilizing the technical matters described in the above-described embodiment. The configurations of the embodiments and the like may be used in appropriate combination.

[0066] In the above embodiment, in step S2 of assembling the inner armour ring 4 to the magnet 2, the inner armour ring 4 formed from a metallic material is heated. As a result, the inner armour ring 4 expands, and a gap can be created between the inner armour ring 4 and the magnet 2. The method of creating a gap between the inner armour ring 4 and the magnet 2 is not limited to heating the inner armour ring 4 formed from a metallic material. In step S2 of assembling the inner armour ring 4 to the magnet 2, the magnet 2 may be cooled without heating the inner armour ring 4. Furthermore, in step S2 of assembling the inner armour ring 4 to the magnet 2, the inner armour ring 4 may be heated and the magnet 2 may be cooled. These methods can also be used to create a gap between the inner armour ring 4 and the magnet 2.

[0067] As shown in Figure 5, the rotor 1A of the first modified example may employ hollow magnets 2A instead of solid magnets 2. A cylindrical shaft 3A is inserted into the hollow magnets 2A. Even when hollow magnets 2A are employed, it is possible to suppress a decrease in the preload applied to the hollow magnets 2A by the inner armoring 4. Furthermore, the rotor 1A of the first modified example can be manufactured using the same method as the rotor 1 of the embodiment.

[0068] As shown in FIG. 6, the inner armor ring 4B of the rotor 1B of the second modified example may have a ring portion 41, a plurality of spoke portions 42, and a shaft portion 43. The ring portion 41 is a cylindrical member having a shape similar to that of the inner armor ring 4 of the embodiment. First ends of the plurality of spoke portions 42 are integrated with the inner circumferential surface 41a of the ring portion 41. The plurality of spoke portions 42 extend from the inner circumferential surface of the ring portion 41 toward the center of the ring portion 41. Second ends of the plurality of spoke portions 42 are integrated with the shaft portion 43. Even in a rotor 1 having such an inner armor ring 4, it is possible to suppress a decrease in the pressure applied by the inner armor ring 4B to the magnet 2B.

[0069] Furthermore, the rotor 1B of the second modified example can also be manufactured by the same method as the rotor 1 of the embodiment. First, the magnet 2B is attached to the inner armor ring 4B. The inner armor ring 4B includes a fan-shaped space formed between adjacent spoke portions 42. The magnet 2B, which has a fan-shaped cross section, is attached to this space. Shrink fitting may be used to attach the magnet 2B to the inner armor ring 4B. Then, the outer armor ring 5 is attached by press fitting.

[0070] In the above embodiment, the magnet 2 is cylindrical and the magnet 2A is cylindrical. In other words, the magnets 2 and 2A are integral. For example, as shown in FIG. 7, a rotor 1C may include multiple magnets 2C. The rotor 1C includes a shaft 3C with a hexagonal cross section and six magnets 2C. A circumscribing circle CD is defined by the outer shapes of the six magnets 2C. Specifically, in the example shown in FIG. 7, the circumscribing circle CD is defined by six ridgelines 2e of each of the six magnets 2C. The inner diameter of the inner armoring 4 is smaller than the diameter of this circumscribing circle CD. This configuration also makes it possible to suppress a decrease in the pressure applied by the inner armoring 4 to the magnet 6C.

[0071] [Note] The present disclosure includes the following contents.

[0072] This disclosure is [1] "A magnet; a first armor ring having a cylindrical shape, including a ring portion in contact with the magnet, and made of a metal material; a second armor ring having a cylindrical shape, in contact with the first armor ring and made of a non-metallic material; A rotor in which, when the magnet, the first armature, and the second armature rotate together, the second armature is less likely to deform than the first armature.

[0073] The present disclosure is [2] "A rotor as described in [1] above, wherein the elastic modulus of the non-metallic material forming the second armoring is greater than the elastic modulus of the metallic material forming the first armoring."

[0074] The present disclosure is [3] "A rotor described in [1] or [2] above, wherein the linear expansion coefficient of the non-metallic material forming the second armoring is smaller than the linear expansion coefficient of the metallic material forming the first armoring."

[0075] The present disclosure states, [4] "The inner diameter of the first armoring is smaller than the diameter of the circumscribed circle defined by the outer peripheral surface of the magnet; The inner diameter of the second armor is smaller than the outer diameter of the first armor; The rotor according to any one of the above [1] to [3], wherein the difference between the inner diameter of the first armoring and the diameter of a circumscribing circle defined by the outer shape of the magnet is larger than the difference between the inner diameter of the second armoring and the outer diameter of the first armoring.

[0076] The present disclosure is [5] "The rotor according to any one of the above [1] to [4], wherein the second armoring is formed from carbon fiber reinforced plastic, which is the non-metallic material."

[0077] The present disclosure also provides a method for manufacturing a magnet by heating a first armoring formed of a metal material and including a cylindrical ring portion or by cooling the magnet, the method comprising the steps of: and a step of press-fitting a cylindrical second armor made of a non-metallic material into the first armor assembled with the magnet without heating the second armor. [Explanation of symbols]

[0078] 1, 1A, 1B, 1C rotors 1S intermediate products 2,2A,2B,2C magnet 2a Magnet outer surface 2c Magnet end face 3, 3A, 3C shaft 31 Shaft 32 Flange 32a Flange outer surface 32c flange end face 4,4B Inner Armoring (1st Armoring) 41 Ring section 41a Inner surface 42 spokes 43 Shaft section 4a Inner armor outer surface 4b Inner armor ring inner surface 4c Inner armor end face 5 Outer Armoring (Second Armoring) 5a Outer armoring surface 5b Inner surface of outer armoring 5c Outer armoring end face 7 Stator 9 rotor 91 Shaft 92 Magnet 93 Armoring 100 motor

Claims

1. A magnet and a first armor ring having a cylindrical shape, including a ring portion in contact with the magnet, and made of a metal material; a second armoring having a cylindrical shape, in contact with the first armoring and made of a non-metallic material; A rotor, wherein when the magnet, the first armature, and the second armature rotate together, the second armature is less likely to deform than the first armature.

2. 2. The rotor of claim 1, wherein the modulus of elasticity of the non-metallic material forming the second armoring is greater than the modulus of elasticity of the metallic material forming the first armoring.

3. 2. The rotor according to claim 1, wherein the coefficient of linear expansion of the non-metallic material forming the second armoring is less than the coefficient of linear expansion of the metallic material forming the first armoring.

4. The inner diameter of the first armoring is smaller than the diameter of a circumscribed circle defined by the outer peripheral surface of the magnet; The inner diameter of the second armor is smaller than the outer diameter of the first armor; The rotor according to claim 1 , wherein a difference between an inner diameter of the first armoring and a diameter of a circumscribed circle defined by an outer shape of the magnet is greater than a difference between an inner diameter of the second armoring and an outer diameter of the first armoring.

5. The rotor according to claim 1 , wherein the second armoring is formed from the non-metallic material, that is, carbon fiber reinforced plastic.

6. a step of combining a first armoring formed of a metal material and including a cylindrical ring portion with the magnet by heating the first armoring or cooling the magnet while providing a gap; and press-fitting a cylindrical second armor made of a non-metallic material into the first armor assembled with the magnet without heating the second armor.

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