Manufacturing method of surface magnet type rotor, and jig for manufacturing surface magnet type rotor

Abstract

To provide a manufacturing method of a surface magnet type rotor that enables high-speed revolution of a motor, simplification of manufacturing processes, and man-hour reduction or the like.SOLUTION: A manufacturing method of a surface magnet type rotor 1 comprising a rotor core 11, a plurality of permanent magnets 12, and a sleeve 13, uses a jig 2 comprising: a substantially cylindrical body part 21; a plurality of protrusions 22 protruding upward, that are arranged side by side in a circumferential direction at an outer peripheral part of an upper face of the body part 21; and an annular notch 23 provided along an outer-peripheral edge on the upper face of the body part 21. The manufacturing method includes the steps of: fitting each of the permanent magnets 12 between the protrusions 22 while inserting a shaft of the rotor core 11 in a hole at a central part of the body part 21 by placing the rotor core 11 on the upper face of the body part 21 of the jig 2; coating an adhesive on an outer peripheral face of each of the permanent magnets 12; and fixing the sleeve 13 by fitting a lower end of the sleeve 13 in the notch 23.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a surface magnet type rotor and a jig for manufacturing a surface magnet type rotor.

Background Art

[0002] There is a high need for high-speed rotation of motors equipped with surface magnet type (SPM: Surface Permanent Magnet) rotors. For this purpose, a technique has been disclosed in which a sleeve is disposed on the outer periphery of a permanent magnet attached to the outer peripheral surface of a rotor core of an SPM rotor so that the permanent magnet is not peeled off from the rotor core by the centrifugal force of high-speed rotation.

[0003] Further, in Patent Document 1, a resin is filled in a first gap formed between the outer peripheral surface of the rotor core and the inner diameter surface of the sleeve, and a second gap formed between the outer peripheral surface of the permanent magnet and the inner peripheral surface of the sleeve, so that the permanent magnet can be fixed to the rotor core without the permanent magnet being separated from the rotor core by the centrifugal force of high-speed rotation. A technique has been disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technique according to Patent Document 1, although the second gap formed between the outer peripheral surface of the permanent magnet and the inner diameter surface of the sleeve is filled with resin, it is necessary to provide two molds and a resin filling process for resin filling, which requires a fairly large amount of equipment and man-hours. That is, in Patent Document 1, there is a problem that further improvement is required for simplifying the manufacturing process of the SPM rotor and shortening the man-hours.

[0006] In view of such problems, the present disclosure aims to provide a method for manufacturing a surface magnet type rotor that realizes high-speed rotation of a motor, and a jig for manufacturing the surface magnet type rotor that can simplify the manufacturing process and reduce man-hours.

Means for Solving the Problems

[0007] The method for manufacturing a surface magnet type rotor of the present disclosure is as follows. A method for manufacturing a surface magnet type rotor including a rotor core, a plurality of permanent magnets arranged side by side in the circumferential direction on the outer peripheral surface of the rotor core, and a sleeve attached to the plurality of permanent magnets so as to cover the outer peripheral surfaces of the plurality of permanent magnets. Using a jig including a main body portion having a substantially cylindrical shape, a plurality of protruding portions arranged side by side in the circumferential direction on the outer peripheral portion of the upper surface of the main body portion and protruding upward, and an annular notch provided along the outer peripheral edge of the upper surface of the main body portion. Placing the rotor core on the upper surface of the main body portion of the jig, inserting the shaft of the rotor core into the hole at the center of the main body portion, and fitting each of the plurality of permanent magnets arranged side by side in the circumferential direction on the outer peripheral surface of the rotor core between the plurality of adjacent protruding portions; a step of applying an adhesive to the outer peripheral surface of the plurality of permanent magnets or the inner peripheral surface of the sleeve; and fitting the lower end of the sleeve into the notch of the jig, and fixing the outer peripheral surface of each of the plurality of permanent magnets and the inner diameter surface of the sleeve with the adhesive.

[0008] A jig for manufacturing a surface magnet type rotor is as follows. A jig for manufacturing a surface magnet type rotor including a rotor core, a plurality of permanent magnets arranged side by side in the circumferential direction on the outer peripheral surface of the rotor core, and a sleeve attached to the plurality of permanent magnets so as to cover the outer peripheral surfaces of the plurality of permanent magnets. Comprising a main body portion having a substantially cylindrical shape, a plurality of protruding portions arranged side by side in the circumferential direction on the outer peripheral portion of the upper surface of the main body portion and protruding upward, and an annular notch provided along the outer peripheral edge of the upper surface of the main body portion. The rotor core is placed on the upper surface of the main body, the shaft of the rotor core is inserted into the hole at the center of the main body, each of the plurality of permanent magnets is fitted between the plurality of protruding portions adjacent to each other, and the lower end of the sleeve is fitted into the notch portion.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide a method for manufacturing a surface magnet type rotor that realizes high-speed rotation of a motor, and a jig for manufacturing the surface magnet type rotor that can simplify the manufacturing process and reduce man-hours.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0011] (Overview of this embodiment) The surface magnet type (SPM: Surface Permanent Magnet) rotor 1 manufactured by the manufacturing method according to this embodiment, which will be described below, includes a rotor core 11, a plurality of permanent magnets 12, and a sleeve 13. The plurality of permanent magnets 12 are arranged and attached side by side in the circumferential direction on the outer peripheral surface of the rotor core 11. The sleeve 13 is arranged so as to cover the outer peripheral surfaces of the plurality of permanent magnets 12, and is further attached to the plurality of permanent magnets 12.

[0012] First, with reference to FIG. 1, an overview of the jig 2 used in the manufacture of the SPM rotor 1 according to this embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of the jig 2 used for manufacturing the SPM rotor 1 according to this embodiment. FIG. 1A is a perspective view of the jig 2. FIG. 1B is a perspective view of the jig 2 with the rotor core 11 and the permanent magnet 12 fitted therein. FIG. 1C is a cross-sectional view of the jig 2 with the rotor core 11, the permanent magnet 12, and the sleeve 13 fitted therein.

[0013] As shown in FIG. 1A, the jig 2 is a member made of a non-magnetic and easily machined material (ultra-super duralumin). The jig 2 includes a main body portion 21, a plurality of protruding portions 22, and a notch portion 23.

[0014] The main body portion 21 is a member serving as a base having a substantially cylindrical shape. As shown in FIG. 1C, the rotor core 11 is placed on the upper surface of the main body portion 21, and the shaft 111 of the rotor core 11 is inserted into the hole at the center of the main body portion 21. Here, the hole at the center of the main body portion 21 is designed such that the central axis of the jig 2 is coaxial with the central axis of the rotor core 11. Specifically, in the inner region R1 of the hole at the center of the main body portion 21, an inlay structure is provided into which the shaft 111 of the rotor core 11 is fitted to make the central axis of the jig 2 coaxial with the central axis of the rotor core 11.

[0015] Also, as shown in Fig. 1A, a plurality of protrusions 22 are arranged side by side in the circumferential direction on the outer peripheral portion of the upper surface of the main body portion 21 and have a shape protruding upward. As shown in Fig. 1B, between a plurality of adjacent protrusions 22, each of the plurality of permanent magnets 12 is fitted. By doing so, the positions of the plurality of permanent magnets 12 are determined to be positions predetermined by the jig 2, and the phases of the plurality of permanent magnets 12 can be accurately guided.

[0016] Also, as shown in Fig. 1A, the notch 23 has an annular notch shape provided along the outer peripheral edge of the upper surface of the main body portion 21. As shown in Fig. 1C, the lower end of the sleeve 13 is fitted into the notch 23. By doing so, the lower end surface and the inner diameter surface of the sleeve 13 are positioned by the notch 23. Further, the notch 23 is designed such that the central axis of the annular notch 23 is coaxial with the central axis of the jig 2. By doing so, the coaxiality of the central axis of the rotor core 11 and the central axis of the sleeve 13 can be guided.

[0017] Subsequently, with reference to Fig. 1, an outline of the manufacturing method of the SPM rotor 1 according to the present embodiment will be described. The manufacturing method of the SPM rotor 1 includes a magnet attaching step, an adhesive applying step, and a sleeve arranging step. <Magnet attaching step> First, in the magnet attaching step, a plurality of permanent magnets 12 are attached side by side in the circumferential direction to the outer peripheral surface of the rotor core 11. Then, the rotor core 11 is placed on the upper surface of the main body portion 21 of the jig 2, and the shaft 111 of the rotor core 11 is inserted into the hole at the central portion of the main body portion 21. At the same time, each of the plurality of permanent magnets 12 is fitted between a plurality of adjacent protrusions 22. <Adhesive applying step> Subsequently, in the adhesive applying step, an adhesive is applied to the outer peripheral surface of the plurality of protrusions 22 fitted in the jig 2 or the inner peripheral surface of the sleeve 13. <Sleeve arranging step> Subsequently, in the sleeve arranging step, the lower end of the sleeve 13 is fitted into the notch 23 of the jig 2. The outer peripheral surface of the permanent magnet 12 and the inner diameter surface of the sleeve 13 are fixed with an adhesive.

[0018] In the manufacturing method of the SPM rotor 1 according to this embodiment, by attaching the sleeve 13 to a plurality of permanent magnets 12 with an adhesive, the plurality of permanent magnets 12 can be fixed to the rotor core 11 without the permanent magnets separating from the rotor core due to the centrifugal force during high-speed rotation. By doing so, the manufacturing method according to this embodiment can manufacture the SPM rotor 1 that can achieve high-speed rotation of the motor.

[0019] Also, in the manufacturing method according to this embodiment, only by using the jig 2, it does not require a large amount of equipment and man-hours as in Patent Document 1. Therefore, in the manufacturing method according to this embodiment, the manufacturing process of the SPM rotor 1 can be simplified and the man-hours can be reduced.

[0020] However, in the process of manufacturing the SPM rotor 1, simply attaching the permanent magnet 12 to the rotor core 11 has a problem that the positioning accuracy between the permanent magnet 12 and the rotor core 11 is likely to deteriorate. In the manufacturing method of this embodiment, using the jig 2, each of the plurality of permanent magnets 12 is fitted and fixed between a plurality of adjacent protrusions 22 of the jig 2. In the manufacturing method according to this embodiment, during the manufacturing process of the SPM rotor 1, the positioning between the permanent magnet 12 and the rotor core 11 can be performed with high accuracy.

[0021] Also, in the process of manufacturing the SPM rotor 1, when simply attaching the sleeve 13 to a plurality of permanent magnets 12 with an adhesive, there is a problem that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 is likely to deteriorate. In the manufacturing method of this embodiment, by using the jig 2 and fitting the lower end of the sleeve 13 into the annular notch 23 of the jig 2, the sleeve 13 is fixed. Therefore, the manufacturing method of this embodiment can make the central axis of the rotor core 11 and the central axis of the sleeve 13 coaxial.

[0022] (Details of this embodiment) Subsequently, with reference to FIGS. 2 to 7, the jig 2 used in the manufacturing of the SPM rotor 1 according to this embodiment and the manufacturing method of the SPM rotor 1 will be described in detail.

[0023] First, the problems according to this embodiment will be described in detail. For a motor to rotate at high speed, there are motor structures and rotor structures suitable for it. Motor structures are roughly classified into an inner rotor type and an outer rotor type. That is, it is classified according to whether the rotating rotor is arranged inside or outside the stator. In the inner rotor type, since the rotor is arranged inside the inner diameter of the stator, the rotation radius becomes small and the moment of inertia also becomes small. Therefore, from the perspective of the moment of inertia, it is considered suitable for high-speed rotation because it can rotate quickly with less energy. On the other hand, in the outer rotor type, since the rotor is arranged on the outer diameter side of the stator, the rotation radius becomes large and the moment of inertia also becomes large. When the rotation radius of the rotor becomes large, a large gap area with the stator can be obtained, so there is an advantage that the generated torque can be increased. However, from the perspective of the moment of inertia, it can be considered not suitable for high rotation because energy is consumed for rotor rotation.

[0024] Rotor structures are roughly classified into a surface magnet type (SPM) rotor and an interior permanent magnet (IPM) rotor. In the SPM rotor, since the permanent magnet is exposed on the rotor surface, it has the characteristics of a large effective magnetic flux amount and a small torque ripple. The SPM rotor can effectively utilize the strong magnetic force of the permanent magnet. However, at high speeds, the magnet is likely to be peeled off by centrifugal force, so it is considered not suitable for high-speed rotation. On the other hand, in the IPM rotor, since the magnet is embedded inside the rotor, there is no risk of scattering due to peeling, and it is considered suitable for high-speed rotation. Also, since the reluctance torque that attracts and repels a part of the yoke (salient pole) can be utilized magnetically, a large total torque can be generated by synthesizing with the magnet torque. Furthermore, the degree of freedom in magnet shape and arrangement is large, and "weakening field magnetization" is possible together with the winding design to reduce iron loss (eddy current loss + hysteresis loss) at high speed.

[0025] However, although the SPM rotor is recognized as not being suitable for high-speed rotation in terms of its structure, there are still specifications and models of SPM rotors that cannot be replaced by IPM rotors. Therefore, the need for high-speed rotation of motors with SPM rotors is high, as proposals for high-speed rotation of motors with SPM rotors have been put forward more than 40 years ago.

[0026] In order to achieve high-speed rotation of a motor with an SPM rotor, for example, a CFRP (Carbon Fiber Reinforced Plastics) sleeve is arranged on the outer periphery of a permanent magnet attached to the outer peripheral surface of the rotor core of the SPM rotor, so that the permanent magnet is prevented from being peeled off from the rotor core by the centrifugal force of high-speed rotation. The carbon fiber, which is the material of the CFRP sleeve, has a thermal expansion coefficient of about 0 [10 -6 / K]. On the other hand, for an electromagnetic steel sheet, the thermal expansion coefficient is 9.6 [10 -6 / K], and for a neodymium magnet, the thermal expansion coefficient is 6.5 [10 -6 / K]. That is, it can be seen that the inner diameter of the CFRP sleeve does not change with respect to temperature change, but the outer diameter expands and contracts repeatedly on the rotor core side of the CFRP sleeve. In a high-temperature environment, the rotor core expands and acts to expand the diameter of the CFRP sleeve from the inside, but in a low-temperature environment, the rotor core contracts and there may be a gap between the CFRP sleeve. If a gap is formed between the rotor core and the CFRP sleeve, it means that the radial holding of the outer peripheral surface of the permanent magnet cannot be achieved, and there is a concern about the peeling of the permanent magnet. In an automotive motor, use in extremely cold regions where the temperature reaches -30°C or -20°C is commonly assumed, which is a fatal structural defect for the SPM rotor.

[0027] Therefore, it is necessary to fix the inner diameter surface of the CFRP sleeve and the outer peripheral surface of the permanent magnet with an adhesive as an intermediate agent. If it is an FIPG-based adhesive called a liquid gasket, when applied to the joint surface, it dries or homogenizes after a certain period of time and can form an elastic film or an adhesive thin layer. This elastic film can fill the difference in thermal expansion coefficients between the CFRP sleeve and the rotor core.

[0028] Therefore, in the manufacturing method for manufacturing the SPM rotor of the present embodiment, a step of fixing the inner diameter surface of the CFRP sleeve (hereinafter referred to as the sleeve) and the outer peripheral surface of each of the plurality of permanent magnets with an adhesive is employed.

[0029] The manufacturing method of the SPM rotor 1 of the present embodiment includes a magnet attaching step, an adhesive applying step, and a sleeve arranging step as follows. <Magnet Attaching Step> FIG. 2 is a diagram showing the magnet attaching step in the manufacturing method of the SPM rotor 1 according to the present embodiment. In the magnet attaching step, as shown in FIGS. 2A and 2B, a plurality of permanent magnets 12 are attached to the magnet attaching surface (11a in FIG. 2A) of the rotor core 11. FIG. 2A is a perspective view showing the state of the rotor core 11 before attaching the plurality of permanent magnets 12. FIG. 2B is a perspective view showing the state of the rotor core 11 after attaching the plurality of permanent magnets 12. After attaching an adhesive, an adhesive tape, or the like to the magnet attaching surface of the rotor core 11 or the inner peripheral surface of the permanent magnet 12, the inner peripheral surface of the permanent magnet 12 is fixed to the magnet attaching surface via the adhesive, the adhesive tape, or the like. Note that if the permanent magnet 12 is magnetized, the permanent magnet 12 is attracted to the rotor core 11 by magnetic force even without using an adhesive or the like. Therefore, an adhesive or the like may not be used for attaching the permanent magnet 12 to the rotor core 11.

[0030] Regarding the positioning of the rotor core 11 and the plurality of permanent magnets 12, as shown in FIGS. 2C and 2D, a concave receiving surface can be provided on the rotor core 11 side to determine the positions of the permanent magnets 12 in the axial direction and the circumferential direction. FIG. 2C is a cross-sectional view showing the state of the rotor core 11 after the plurality of permanent magnets 12 are attached. FIG. 2C is a top view showing the state of the rotor core 11 after the plurality of permanent magnets 12 are attached. However, a clearance for fitting with the permanent magnet 12 is always necessary on the concave receiving surface of the rotor core 11. Considering the temperature change from -30°C to 100°C, the thermal expansion coefficients of the rotor core 11 and the permanent magnet 12 are different. Therefore, it is necessary to appropriately set the clearance so that the permanent magnet 12 is not damaged due to the low-temperature shrinkage of the rotor core 11. Thus, in applications with a large temperature change, even if a concave receiving surface is provided on the rotor core 11 side, it is necessary to design the clearance for thermal displacement and machining error differences, and there is a problem that the positioning accuracy between the permanent magnet 12 and the rotor core 11 is likely to deteriorate.

[0031] <Adhesive application process> FIG. 3 is a diagram showing the adhesive application process in the method for manufacturing the SPM rotor 1 according to the present embodiment. In the adhesive application step, in order to fix the outer peripheral surfaces of the plurality of permanent magnets 12 and the inner diameter surface of the sleeve 13, as shown in FIG. 3A, an adhesive 14 is applied to the outer peripheral surface of each of the plurality of permanent magnets 12. FIG. 3A is a perspective view showing a state in which the adhesive 14 is applied to the outer peripheral surface of each of the plurality of permanent magnets 12. As shown in FIG. 3B, the adhesive 14 may be applied to the attachment region of the inner diameter surface of the sleeve 13 with the plurality of permanent magnets 12. FIG. 3B is a perspective view showing a state in which the adhesive 14 is applied to the inner diameter surface of the sleeve 13. In these methods, the necessary minimum amount of the adhesive 14 can be applied only to the necessary parts and the application state can be directly monitored. Therefore, a means of thinly and uniformly applying the adhesive 14 directly using an application device such as a dispenser is efficient. Whether the adhesive 14 is applied to the outer peripheral surface of the plurality of permanent magnets 12 or to the inner diameter surface of the sleeve 13 is effective. However, it is easier because when the adhesive 14 is applied to the outer peripheral surface of the plurality of permanent magnets 12, it is less restricted by the dimensions and operating range of the application device.

[0032] <Sleeve Arrangement Step> FIG. 4 is a view showing the sleeve arrangement step in the method for manufacturing the SPM rotor 1 according to the present embodiment. In the sleeve arrangement step, as shown in FIG. 4A, the sleeve 13 is inserted by clearance fitting so that the outer peripheral surface of each of the plurality of permanent magnets 12 and the inner diameter surface of the sleeve 13 are in contact with the rotor core 11 to which the plurality of permanent magnets 12 are attached. FIG. 4A is a perspective view showing the state at the start of insertion and the state during insertion of the sleeve 13 with respect to the rotor core 11 to which the plurality of permanent magnets 12 are attached. As shown in FIG. 4A, since a gap between the outer peripheral surface of each of the permanent magnets 12 and the inner diameter surface of the sleeve 13 must have the adhesive 14 intervening, it is preferable to secure a gap of about 0.1 to 0.2 mm on one side.

[0033] However, due to the gap of about 0.1 to 0.2 mm on one side, there is a problem that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 is likely to deteriorate. FIG. 4B is a diagram showing an image when the coaxiality between the central axis (AX11 in this figure) of the rotor core 11 and the central axis (AX13 in this figure) of the sleeve 13 deteriorates. As shown in FIG. 4B, when there is a gap over the entire circumference between the inner diameter surface of the sleeve 13 and the outer circumference surface of the permanent magnet 12, the sleeve 13 can be displaced by the amount of the gap, resulting in a deviation between the central axes.

[0034] As described above, the method of fixing the sleeve 13 to the plurality of permanent magnets 12 with the adhesive 14 has the following problems. (1) There is a problem that the positioning accuracy between the plurality of permanent magnets 12 and the rotor core 11 is likely to deteriorate in the magnet attaching process. (2) There is a problem that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 is likely to deteriorate in the sleeve arranging process.

[0035] Subsequently, a countermeasure against the problem (1) that the positioning accuracy between the permanent magnet 12 and the rotor core 11 is likely to deteriorate in the magnet attaching process of the manufacturing method of the SPM rotor 1 of the present embodiment will be described. The reason why the positioning accuracy is likely to deteriorate is due to the different thermal expansion coefficients of the permanent magnet 12 and the rotor core 11. In order to avoid the interference between the permanent magnet 12 and the rotor core 11 due to the thermal expansion and contraction of the rotor core 11, the gap between the concave receiving surface of the rotor core 11 and the permanent magnet 12 has to be provided larger. Therefore, the space in which the permanent magnet 12 can be displaced becomes larger, and when trying to position with the rotor core 11, the accuracy deteriorates more than the positioning between ordinary steel materials.

[0036] To solve this problem, it is found that it is effective to use another component instead of the rotor core 11 for positioning the permanent magnet 12. If the difference in the thermal expansion coefficients of the permanent magnet 12 and the rotor core 11 is the problem, a jig 2 for positioning the permanent magnet 12 can be separately prepared so as not to be affected by the temperature difference. Since the jig 2 is removed after assembly, it is not affected by the temperature change from -30°C to 100°C, which is the usage environment of the rotor core 11 and the like. Therefore, the dimensions of the jig 2 are designed such that the gap with the permanent magnet 12 is minimized at the normal temperature of 20 to 25°C during assembly.

[0037] FIG. 5 is a diagram showing an example of a method for positioning a plurality of permanent magnets 12 in the manufacturing method of the SPM rotor 1 according to the present embodiment.

[0038] As shown in FIG. 5, in the positioning method, first, the rotor core 11 with a plurality of permanent magnets 12 attached side by side in the circumferential direction on the outer peripheral surface is inserted into the jig 2 from above. At the time of insertion, the rotor core 11 is placed on the upper surface of the main body portion 21, and the shaft 111 of the rotor core 11 is inserted into the hole at the center of the main body portion 21. Further, each of the plurality of permanent magnets 12 is fitted between a plurality of protruding portions 22 adjacent to each other. Note that after the rotor core 11 is inserted into the jig 2, the plurality of permanent magnets 12 may be fitted into the jig 2, and at that time, the plurality of permanent magnets 12 may be attached side by side in the circumferential direction on the outer peripheral surface of the rotor core 11.

[0039] FIG. 6 is a diagram showing an example of a structure for positioning a plurality of permanent magnets 12 in the jig 2 used for manufacturing the SPM rotor 1 according to the present embodiment. FIG. 6A is a perspective view of a plurality of protrusions 22 of the jig 2. As shown in FIG. 6A, the plurality of protrusions 22 are arranged side by side in the circumferential direction on the outer peripheral portion of the upper surface of the main body portion 21 and have a shape protruding upward. A permanent magnet 12 can be fitted between two surfaces of a plurality of adjacent protrusions 22 of the jig 2. The distance between two surfaces of the plurality of protrusions 22 is designed to match the circumferential width of the permanent magnet 12. The distance between two surfaces of the plurality of protrusions 22 can be manufactured with high precision by being created by milling through cutting. By doing so, since the fitting with the permanent magnet 12 can be set with a minimum gap, high-precision phase alignment becomes possible. Further, FIG. 6B is a top view of a plurality of protrusions 22 of the jig 2 in which the permanent magnet 12 is fitted. As shown in FIG. 6B, the phase of the fitted permanent magnet 12 is made to coincide with the reference phase of the jig 2. Note that although it is desirable that the plurality of protrusions 22 are integrally formed with the main body portion 21, they may be separate bodies as long as the machining accuracy and the assembly accuracy reach the target values.

[0040] FIG. 6C is a cross-sectional view of the jig 2 in a state where the rotor core 11 and a plurality of permanent magnets 12 are fitted. FIG. 6D is an enlarged view of FIG. 6C. As shown in FIG. 6C, the rotor core 11 is placed on the upper surface of the main body portion 21, and the shaft 111 of the rotor core 11 is inserted into a hole in the central portion of the main body portion 21. In a region R1 inside the hole in the central portion of the main body portion 21, an inlay structure for fixing the inserted shaft 111 of the rotor core 11 is provided to make the central axis of the jig 2 and the central axis of the rotor core 11 coaxial. Further, as shown in FIG. 6D, in a region R2 on the outer peripheral portion of the upper surface of the main body portion 21, a receiving surface for the permanent magnet 12 for determining the axial position of each of the plurality of permanent magnets 12 is provided.

[0041] As described above, in the manufacturing method of the SPM rotor 1 of the present embodiment, by using the jig 2, the positioning of the plurality of permanent magnets 12 and the rotor core 11 is accurately performed.

[0042] Next, a countermeasure against the problem (2) that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 is likely to deteriorate in the sleeve arrangement process of the present embodiment will be described. The reason why the coaxiality is likely to deteriorate is that since each of the sleeve 13 and the plurality of permanent magnets 12 must be fixed with an adhesive 14, there is a gap for applying the adhesive 14. Since the sleeve 13 is connected to the permanent magnet 12 only via the adhesive 14, it is not supported by either the permanent magnet 12 or the rotor core 11 and is in a state where it can be displaced by the amount of the gap of the adhesive 14. Therefore, in the worst case, as described above with reference to FIG. 4B, the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 deteriorates by the amount of the gap of the adhesive 14.

[0043] To solve this problem, in order to make the central axis of the rotor core 11 and the central axis of the sleeve 13 coaxial, it is also effective to use another part here. Since the thermal displacement between the permanent magnet 12 and the rotor core 11 is a problem, it is preferable to use a jig that is not affected by the temperature difference. As the jig, a jig 2 for positioning the plurality of permanent magnets 12 is diverted. After positioning the plurality of permanent magnets 12, the central axis of the sleeve 13 and the central axis of the rotor core 11 are aligned to be coaxial using the same jig 2. Note that the jig 2 may also be used as a jig only for making the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0044] FIG. 7 is a diagram showing an example of a structure for making the central axis of the rotor core 11 and the central axis of the sleeve 13 coaxial in the jig 2 used for manufacturing the SPM rotor 1 according to the present embodiment. FIG. 7A is a cross-sectional view of the jig 2 with the rotor core 11, a plurality of permanent magnets 12, and the sleeve 13 fitted therein. As shown in FIG. 7A, the jig 2 includes a notch 23. The notch 23 has an annular notch shape provided along the outer peripheral edge of the upper surface of the main body portion 21. The lower end of the sleeve 13 can be fitted into the notch 23. When the lower end of the sleeve 13 is fitted into the notch 23, the position of the lower end surface and the inner diameter surface of the sleeve 13 is determined by the notch 23. Further, the notch 23 is designed such that the central axis of the annular notch 23 is coaxial with the central axis of the hole in the central portion of the main body portion 21. Therefore, as shown in this figure, the central axis of the sleeve 13 fitted into the jig 2 and the central axis of the shaft 111 of the rotor core 11 fitted into the hole in the central portion of the main body portion 21 are coaxial. That is, the jig 2 can make the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0045] However, this method is premised on the fact that the lower end surface of the sleeve 13 protrudes below the lower end surface of the permanent magnet 12. If the inner diameter surface of the sleeve 13 is not exposed, the sleeve 13 cannot be fitted into the notch 23 of the jig 2.

[0046] In addition, not only on the lower end side of the sleeve 13, but also on the upper end side of the sleeve 13, the jig 3 shown in FIG. 7B may be used to make the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial. FIG. 7B is a cross-sectional view of the jig 3 with the rotor core 11, a plurality of permanent magnets 12, and the sleeve 13 fitted therein. As shown in FIG. 7B, the jig 3 has a substantially annular shape. The shaft 111 of the rotor core 11 is fitted into the hole in the central portion of the jig 3. The hole in the central portion of the jig 3 is designed such that the central axis of the rotor core 11 and the central axis of the jig 3 are coaxial. Further, the outer diameter of the jig 3 is designed to match the inner diameter of the sleeve 13. Therefore, by fitting the shaft 111 of the rotor core 11 into the hole in the central portion of the jig 3 and fixing the inner diameter surface on the upper end side of the sleeve 13 with the outer diameter surface of the jig 3, the central axis of the rotor core 11 and the central axis of the sleeve 13 can be made coaxial.

[0047] As described above, in the method for manufacturing the SPM rotor 1 of the present embodiment, by using the jig 2 and the jig 3, the central axis of the rotor core 11 and the central axis of the sleeve 13 can be made coaxial on each of the lower end side and the upper end side of the sleeve 13. Furthermore, the inclination of the sleeve 13 can be suppressed, and the difference in coaxiality between the upper end side and the lower end side of the sleeve 13 can be adjusted to be minimized.

[0048] (Modification example) Subsequently, a modification example of the method for manufacturing the SPM rotor 1 of the above-described embodiment will be described. In the above-described embodiment, when the lower end surface of the sleeve 13 does not protrude below the lower end surface of the permanent magnet 12 and the inner diameter surface of the sleeve 13 is not exposed, the sleeve 13 cannot be fitted into the notch 23 of the jig 2 (see FIG. 7). Hereinafter, a method for manufacturing the SPM rotor 1 according to a modification example in which the central axis of the rotor core 11 and the central axis of the sleeve 13 can be made coaxial will be described.

[0049] In the method for manufacturing the SPM rotor 1 according to the modification example, the jig 4 is used instead of the jig 2, and the jig 5 is used instead of the jig 3. FIG. 8 is a diagram showing an example of the structure of the jigs (jig 4 and jig 5) used in the method for manufacturing the SPM rotor 1 according to the modification example. FIG. 8A is a cross-sectional view of the jig 4 in a state where the rotor core 11, the plurality of permanent magnets 12, and the sleeve 13 are fitted. As shown in FIG. 8A, the jig 4 has a configuration basically the same as that of the jig 2, but includes a protruding portion 44 instead of the annular notch 23. The protruding portion 44 has an annular shape along the outer peripheral edge of the upper surface of the main body portion 21 and protrudes upward. The protruding portion 44 is designed such that the inner diameter surface of the protruding portion 44 fixes the outer diameter surface of the sleeve 13. Here, with respect to the lower end surface of the sleeve 13, it is fixed by the upper surface of the main body portion 21. Further, the central axis of the annular protruding portion 44 is designed to be coaxial with the central axis of the jig 4. Therefore, the central axis of the sleeve 13 and the central axis of the rotor core 11 can be made coaxial by the jig 4.

[0050] FIG. 8B is a cross-sectional view of the jig 5 fitted into the rotor core 11, the plurality of permanent magnets 12, and the sleeve 13. The jig 5 has an annular shape. The shaft 111 of the rotor core 11 is fitted into the hole at the center of the jig 5. The hole at the center of the jig 5 is designed such that the central axis of the rotor core 11 and the central axis of the jig 5 are coaxial. Further, the jig 5 includes an annular protrusion along the outer peripheral edge of the lower surface and protruding downward. The inner diameter surface of the protrusion of the jig 5 is designed to fix the outer diameter surface of the upper end side of the sleeve 13 and make the central axis of the sleeve 13 and the central axis of the jig 5 coaxial. Therefore, the jig 5 can make the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0051] Here, it is preferable that the jig 5 is fitted into the shaft 111 of the rotor core 11 and the sleeve 13 after the sleeve 13 is pushed to the lower end by a pressure pipe or the like. Further, the jig 5 may be used as a holding jig until the adhesive 14 interposed between the inner diameter surface of the sleeve 13 and the outer peripheral surface of the plurality of permanent magnets 12 cures.

[0052] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit thereof.

Description of Reference Numerals

[0053] 1 Surface Magnet Type (SPM) Rotor, 2, 3, 4, 5 Jig, 11 Rotor Core, 12 Permanent Magnet, 13 Sleeve, 14 Adhesive, 21 Main Body Portion, 22 Protrusion, 23 Notch, 44 Protrusion, 111 Shaft

Claims

1. A method for manufacturing a surface magnet type rotor, comprising: a rotor core; a plurality of permanent magnets arranged side by side in the circumferential direction on the outer peripheral surface of the rotor core; and a sleeve attached to the plurality of permanent magnets so as to cover the outer peripheral surfaces of the plurality of permanent magnets. Using a jig comprising: a main body portion having a substantially cylindrical shape; a plurality of protruding portions arranged side by side in the circumferential direction at the outer peripheral portion of the upper surface of the main body portion and protruding upward; and an annular notch provided along the outer peripheral edge of the upper surface of the main body portion. A step of placing the rotor core on the upper surface of the main body portion of the jig, inserting the shaft of the rotor core into the hole at the center of the main body portion, and fitting each of the plurality of permanent magnets attached side by side in the circumferential direction on the outer peripheral surface of the rotor core between the plurality of adjacent protruding portions. A step of applying an adhesive to the outer peripheral surface of the plurality of permanent magnets or the inner peripheral surface of the sleeve. A step of fitting the lower end of the sleeve into the notch of the jig and fixing the outer peripheral surface of each of the plurality of permanent magnets and the inner diameter surface of the sleeve with the adhesive. A method for manufacturing a surface magnet type rotor.

2. The hole at the center of the main body portion of the jig is designed such that the central axis of the hole at the center of the main body portion is coaxial with the central axis of the shaft of the rotor core. The annular notch is designed such that the central axis of the annular notch is coaxial with the central axis of the hole at the center of the main body portion. The method for manufacturing a surface magnet type rotor according to Claim 1.

3. A jig for manufacturing a surface magnet type rotor, comprising: a rotor core; a plurality of permanent magnets arranged side by side in the circumferential direction on the outer peripheral surface of the rotor core; and a sleeve attached to the plurality of permanent magnets so as to cover the outer peripheral surfaces of the plurality of permanent magnets. A main body portion having a substantially cylindrical shape. A plurality of protruding portions arranged side by side in the circumferential direction at the outer peripheral portion of the upper surface of the main body portion and protruding upward. An annular notch provided along the outer peripheral edge of the upper surface of the main body portion. The rotor core is placed on the upper surface of the main body portion, and the shaft of the rotor core is inserted into the hole at the central portion of the main body portion. Each of the plurality of permanent magnets is fitted between the plurality of protruding portions adjacent to each other. The lower end of the sleeve is fitted into the notch. A jig for manufacturing a surface magnet type rotor.

4. The hole at the central portion of the main body portion of the jig is designed such that the central axis of the hole at the central portion of the main body portion is coaxial with the central axis of the shaft of the rotor core. The annular notch is designed such that the central axis of the annular notch is coaxial with the central axis of the hole at the central portion of the main body portion. A jig for manufacturing a surface magnet type rotor according to claim 3.

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