Method for manufacturing a surface-mounted magnetic rotor and a jig for manufacturing a surface-mounted magnetic 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.

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 relatively large amount of equipment and labor. 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 working hours.

[0006] In light of these challenges, this disclosure aims to provide a method for manufacturing a surface magnet rotor that enables high-speed rotation of motors, as well as a jig for manufacturing a surface magnet rotor that simplifies the manufacturing process and reduces the number of steps required. [Means for solving the problem]

[0007] The method for manufacturing a surface magnet type rotor according to the present disclosure is: A method for manufacturing a surface magnet type rotor comprising a rotor core, a plurality of permanent magnets attached to the outer surface of the rotor core in a circumferential direction, and a sleeve attached to the plurality of permanent magnets so as to cover the outer surface of the plurality of permanent magnets, Using a jig comprising a main body having a substantially cylindrical shape, a plurality of protrusions arranged circumferentially on the outer circumference of the upper surface of the main body and projecting upward, and an annular notch provided along the outer peripheral edge of the upper surface of the main body, The process includes: placing the rotor core on the upper surface of the main body of the jig, inserting the shaft of the rotor core into the hole in the center of the main body, and fitting each of the multiple permanent magnets attached to the outer surface of the rotor core in a circumferential direction between adjacent multiple protrusions; applying adhesive to the outer surfaces of the multiple permanent magnets or the inner surface of the sleeve; fitting the lower end of the sleeve into the notch of the jig, and fixing the outer surfaces of each of the multiple permanent magnets and the inner diameter surface of the sleeve with the adhesive.

[0008] The jig for manufacturing surface magnet type rotors is, A jig for manufacturing a surface magnet type rotor, comprising a rotor core, a plurality of permanent magnets attached to the outer surface of the rotor core in a circumferential direction, and a sleeve attached to the plurality of permanent magnets so as to cover the outer surface of the plurality of permanent magnets, It comprises a main body having a substantially cylindrical shape, a plurality of protrusions arranged in the circumferential direction on the outer circumference of the upper surface of the main body and projecting upward, and an annular notch provided along the outer peripheral edge of the upper surface of the main body, The rotor core is placed on the upper surface of the main body, the shaft of the rotor core is inserted into a hole in the center of the main body, each of the plurality of permanent magnets is fitted between the plurality of adjacent protrusions, and the lower end of the sleeve is fitted into the notch. [Effects of the Invention]

[0009] This disclosure provides a method for manufacturing a surface magnet rotor that enables high-speed rotation of motors, as well as a jig for manufacturing a surface magnet rotor that simplifies the manufacturing process and reduces the number of steps required. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the configuration of a jig used in the manufacture of an SPM rotor according to this embodiment. [Figure 2] This figure shows the magnet attachment process in the manufacturing method of the SPM rotor according to this embodiment. [Figure 3] This figure shows the adhesive application step in the manufacturing method of the SPM rotor according to this embodiment. [Figure 4] This figure shows the sleeve placement step in the manufacturing method of the SPM rotor according to this embodiment. [Figure 5] This figure shows an example of a method for positioning multiple permanent magnets in the manufacturing method of an SPM rotor according to this embodiment. [Figure 6] This figure shows an example of a structure for positioning multiple permanent magnets 12 in a jig used in the manufacture of an SPM rotor according to this embodiment. [Figure 7] This figure shows an example of a structure for making the central axis of the rotor core and the central axis of the sleeve coaxial in a jig used for manufacturing an SPM rotor according to this embodiment. [Figure 8] This figure shows an example of the structure of a jig used in the manufacturing method of the modified SPM rotor 1. [Modes for carrying out the invention]

[0011] (Summary 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 attached side by side in the circumferential direction to the outer peripheral surface of the rotor core 11. The sleeve 13 is disposed so as to cover the outer peripheral surface 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 for manufacturing the SPM rotor 1 according to this embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of a 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 magnets 12 fitted therein. FIG. 1C is a cross-sectional view of the jig 2 with the rotor core 11, the permanent magnets 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 machinable 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 central portion of the main body portion 21. Here, the hole at the central portion 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, an inlay structure for fitting the shaft 111 of the rotor core 11 to make the central axis of the jig 2 coaxial with the central axis of the rotor core 11 is provided in the inner region R1 of the hole at the central portion of the main body portion 21.

[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 at 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 between the central axis of the rotor core 11 and the central axis of the sleeve 13 can be guided.

[0017] Subsequently, using 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 in 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, the sleeve 13 is attached to the multiple permanent magnets 12 with adhesive, so that the permanent magnets do not detach from the rotor core due to the centrifugal force of high-speed rotation, and the multiple permanent magnets 12 can be fixed to the rotor core 11. In this way, the manufacturing method according to this embodiment makes it possible to manufacture an SPM rotor 1 that can achieve high-speed rotation of the motor.

[0019] Furthermore, the manufacturing method according to this embodiment does not require the large-scale equipment and man-hours described in Patent Document 1, as it only requires the use of jig 2. Therefore, the manufacturing method according to this embodiment simplifies the manufacturing process and reduces the man-hours required for the SPM rotor 1.

[0020] However, if the SPM rotor 1 is manufactured by simply attaching the permanent magnets 12 to the rotor core 11, there is a problem in that the positioning accuracy between the permanent magnets 12 and the rotor core 11 tends to deteriorate. In the manufacturing method of this embodiment, a jig 2 is used, and each of the multiple 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, the positioning between the permanent magnets 12 and the rotor core 11 can be performed with high precision during the manufacturing process of the SPM rotor 1.

[0021] Furthermore, if the SPM rotor 1 is simply attached to multiple permanent magnets 12 with adhesive during the manufacturing process, there is a problem that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 tends to deteriorate. In the manufacturing method of this embodiment, the sleeve 13 is fixed by fitting the lower end of the sleeve 13 into the annular notch 23 of the jig 2. Therefore, in the manufacturing method of this embodiment, the central axis of the rotor core 11 and the central axis of the sleeve 13 can be made coaxial.

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

[0023] First, the problems associated with this embodiment will be described in detail. To achieve high-speed rotation of a motor, there are suitable motor and rotor structures. Motor structures are broadly classified into inner rotor type and outer rotor type. In other words, they are classified by whether the rotating rotor is located inside or outside the stator. In the inner rotor type, the rotor is located inside the stator, resulting in a smaller radius of rotation and a smaller moment of inertia. Therefore, from the perspective of the moment of inertia, it can rotate quickly with less energy, making it suitable for high-speed rotation. In contrast, in the outer rotor type, the rotor is located on the outer side of the stator, resulting in a larger radius of rotation and a larger moment of inertia. While a larger rotor radius allows for a larger gap area with the stator, which has the advantage of generating greater torque, from the perspective of the moment of inertia, it consumes more energy for rotor rotation, making it unsuitable for high-speed rotation.

[0024] Rotor structures are broadly classified into surface-mounted magnet (SPM) rotors and interior-permanent magnet (IPM) rotors. SPM rotors have permanent magnets exposed on the rotor surface, resulting in a large effective magnetic flux and low torque ripple. While SPM rotors effectively utilize the strong magnetic force of permanent magnets, they are considered unsuitable for high-speed rotation because the magnets are prone to detaching due to centrifugal force. On the other hand, IPM rotors have magnets embedded inside the rotor, eliminating the risk of scattering due to detachment, and are considered suitable for high-speed rotation. Furthermore, because they utilize reluctance torque, which attracts and repels a portion of the yoke (salliance pole) in a magnetic circuit, it is possible to generate a large total torque by combining it with the magnetic torque. In addition, there is a great degree of freedom in the shape and arrangement of the magnets, and along with the winding design, "field weakening" is possible to reduce iron loss (eddy current loss + hysteresis loss) at high speeds.

[0025] However, although SPM rotors are recognized as structurally unsuitable for high-speed rotation, there are specifications and models of SPM rotors that cannot be replaced by IPM rotors. For this reason, there is a high demand for high-speed motor rotation using SPM rotors, as proposals for this have been made for over 40 years.

[0026] To achieve high-speed rotation of motors using SPM rotors, for example, a CFRP (Carbon Fiber Reinforced Plastics) sleeve is placed around the outer circumference of the permanent magnets attached to the outer surface of the rotor core of the SPM rotor, preventing the permanent magnets from detaching from the rotor core due to the centrifugal force of high-speed rotation. The carbon fiber material of the CFRP sleeve has a coefficient of thermal expansion of approximately 0[10 -6

[10] . In contrast, the coefficient of thermal expansion for electrical steel sheets is 9.6[10 -6 [K], neodymium magnets have a coefficient of thermal expansion of 6.5 [10 -6 [K]. In other words, the inner diameter of the CFRP sleeve does not change with temperature changes, but the outer diameter of the CFRP sleeve on the rotor core side repeatedly expands and contracts. In high-temperature environments, the rotor core expands and acts to enlarge the CFRP sleeve from the inside, but in low-temperature environments, the rotor core contracts, and a gap may form between it and the CFRP sleeve. If a gap forms between the rotor core and the CFRP sleeve, the radial support of the outer surface of the permanent magnet is not maintained, and there is a concern that the permanent magnet may detach. In automotive motors, use in extremely cold regions where temperatures reach -30°C or -20°C is commonplace, so this would be a fatal structural defect for an SPM rotor.

[0027] Therefore, the inner diameter surface of the CFRP sleeve and the outer surface of the permanent magnet need to be fixed together with an intermediate adhesive. If an FIPG-based adhesive, also known as a liquid gasket, is used, it can be applied to the joint surface and, after a certain period of time, dry or become uniform, forming an elastic film or a sticky thin layer. This elastic film can bridge the difference in thermal expansion coefficients between the CFRP sleeve and the rotor core.

[0028] Therefore, the manufacturing method for the SPM rotor of this embodiment employs a step of fixing the inner diameter surface of the CFRP sleeve (hereinafter referred to as the sleeve) and the outer circumferential surfaces of each of the multiple permanent magnets with an adhesive.

[0029] The manufacturing method of the SPM rotor 1 in this embodiment includes a magnet attachment step, an adhesive application step, and a sleeve placement step, as follows. <Magnet attachment process> Figure 2 shows the magnet attachment process in the manufacturing method of the SPM rotor 1 according to this embodiment. In the magnet attachment process, as shown in Figures 2A and 2B, multiple permanent magnets 12 are attached to the magnet attachment surface (11a in Figure 2A) of the rotor core 11. Figure 2A is a perspective view showing the state of the rotor core 11 before the attachment of the multiple permanent magnets 12. Figure 2B is a perspective view showing the state of the rotor core 11 after the attachment of the multiple permanent magnets 12. After applying adhesive or adhesive tape to the magnet attachment surface of the rotor core 11 or the inner circumferential surface of the permanent magnet 12, the inner circumferential surface of the permanent magnet 12 is fixed to the magnet attachment surface via the adhesive or adhesive tape. Note that once the permanent magnet 12 has been magnetized, the permanent magnet 12 will be attracted to the rotor core 11 by magnetic force even without the use of adhesive. Therefore, adhesive does not need to be used to attach the permanent magnet 12 to the rotor core 11.

[0030] Furthermore, regarding the positioning of the rotor core 11 and the multiple permanent magnets 12, as shown in Figures 2C and 2D, it is possible to determine the position of the permanent magnets 12 in the axial and circumferential directions by providing a concave receiving surface on the rotor core 11 side. Figure 2C is a cross-sectional view showing the state of the rotor core 11 after the multiple permanent magnets 12 have been attached. Figure 2C is a top view showing the state of the rotor core 11 after the multiple permanent magnets 12 have been attached. However, the concave receiving surface of the rotor core 11 must have clearance for fitting with the permanent magnets 12. Considering the temperature change from -30°C to 100°C, the thermal expansion coefficients of the rotor core 11 and the permanent magnets 12 are different. Therefore, it is necessary to set the clearance appropriately so that the permanent magnets 12 are not damaged by the low-temperature contraction of the rotor core 11. Thus, in applications with large temperature changes, even if a concave receiving surface is installed on the rotor core 11 side, clearance for thermal displacement and machining errors must be designed, which presents the challenge of easily deteriorating the positioning accuracy between the permanent magnets 12 and the rotor core 11.

[0031] <Adhesive application process> Figure 3 shows the adhesive application step in the manufacturing method of the SPM rotor 1 according to this embodiment. In the adhesive application process, adhesive 14 is applied to the outer surfaces of each of the multiple permanent magnets 12, as shown in Figure 3A, in order to fix the outer surfaces of the multiple permanent magnets 12 to the inner diameter surface of the sleeve 13. Figure 3A is a perspective view showing the state in which adhesive 14 has been applied to the outer surfaces of each of the multiple permanent magnets 12. Alternatively, as shown in Figure 3B, the adhesive 14 may be applied to the bonding area between the multiple permanent magnets 12 and the inner diameter surface of the sleeve 13. Figure 3B is a perspective view showing the state in which adhesive 14 has been applied to the inner diameter surface of the sleeve 13. With these methods, the minimum necessary amount of adhesive 14 can be applied only to the necessary parts, and the application state can be directly monitored. Therefore, a means of directly applying the adhesive 14 thinly and uniformly using an application device such as a dispenser is efficient. It is effective whether the adhesive 14 is applied to the outer surfaces of the multiple permanent magnets 12 or to the inner diameter surface of the sleeve 13. However, applying the adhesive 14 to the outer surfaces of the multiple permanent magnets 12 is easier because it is less constrained by the dimensions and operating range of the application device.

[0032] <Sleeve placement process> Figure 4 shows the sleeve placement step in the manufacturing method of the SPM rotor 1 according to this embodiment. In the sleeve placement process, as shown in Figure 4A, the sleeve 13 is inserted into the rotor core 11 to which the multiple permanent magnets 12 are attached, using a gap-fitting method, such that the inner diameter surface of the sleeve 13 is in contact with the outer circumferential surface of each of the multiple permanent magnets 12. Figure 4A is a perspective view showing the state at the start of insertion and the state during insertion of the sleeve 13 into the rotor core 11 to which the multiple permanent magnets 12 are attached. As shown in Figure 4A, a gap of about 0.1 to 0.2 mm on each side is preferably secured between the outer circumferential surface of each permanent magnet 12 and the inner diameter surface of the sleeve 13, as adhesive 14 must be interposed.

[0033] However, this gap of about 0.1 to 0.2 mm on one side presents a problem in that the coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 tends to deteriorate. Figure 4B shows an image of what happens when the coaxiality between the central axis of the rotor core 11 (AX11 in this figure) and the central axis of the sleeve 13 (AX13 in this figure) deteriorates. As shown in Figure 4B, if there is a gap around 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, causing misalignment of each central axis.

[0034] As described above, the method of fixing the sleeve 13 to multiple permanent magnets 12 with adhesive 14 has the following problems. (1) A problem in the magnet attachment process is that the positioning accuracy between the multiple permanent magnets 12 and the rotor core 11 tends to deteriorate. (2) A problem in the sleeve placement process is that the degree of coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 tends to deteriorate.

[0035] Next, we will explain countermeasures to address the problem (1) that the positioning accuracy between the permanent magnet 12 and the rotor core 11 tends to deteriorate during the magnet attachment process in the manufacturing method of the SPM rotor 1 of this embodiment. The reason why positioning accuracy tends to deteriorate is due to the difference in thermal expansion coefficients between the permanent magnet 12 and the rotor core 11. In order to avoid interference between the permanent magnet 12 and the rotor core 11 due to the thermal expansion and cooling contraction of the rotor core 11, it becomes necessary to provide a larger gap between the concave receiving surface of the rotor core 11 and the permanent magnet 12. As a result, the space in which the permanent magnet 12 can be displaced becomes larger, and when attempting to position using the rotor core 11, the accuracy deteriorates compared to positioning between ordinary steel materials.

[0036] To solve this problem, it becomes clear that using a different component instead of the rotor core 11 for positioning the permanent magnet 12 is effective. If the difference in thermal expansion coefficients between the permanent magnet 12 and the rotor core 11 is the problem, then a separate jig 2 for positioning the permanent magnet 12 can be prepared to avoid the effects of temperature differences. Since the jig 2 is removed after assembly, it is not affected by the temperature fluctuations from -30°C to 100°C that are the operating environment for the rotor core 11, etc. Therefore, the dimensions of the jig 2 are designed so that the gap with the permanent magnet 12 is minimized at the room temperature of 20-25°C during assembly.

[0037] Figure 5 shows an example of a method for positioning multiple permanent magnets 12 in the manufacturing method of the SPM rotor 1 according to this embodiment.

[0038] As shown in Figure 5, in the positioning method, first, a rotor core 11, on which multiple permanent magnets 12 are attached in a circumferential direction on its outer surface, is inserted into the jig 2 from above. During insertion, the rotor core 11 is placed on the upper surface of the main body 21, and the shaft 111 of the rotor core 11 is inserted into the hole in the center of the main body 21. In addition, each of the multiple permanent magnets 12 is fitted between multiple adjacent protrusions 22. Furthermore, after the rotor core 11 is inserted into the jig 2, multiple permanent magnets 12 may be fitted into the jig 2, and at that time, multiple permanent magnets 12 may be attached to the outer surface of the rotor core 11 in a circumferential direction.

[0039] Figure 6 shows an example of a structure for positioning multiple permanent magnets 12 in a jig 2 used in the manufacture of the SPM rotor 1 according to this embodiment. Figure 6A is a perspective view of the multiple protrusions 22 of the jig 2. As shown in Figure 6A, the multiple protrusions 22 are arranged in a circumferential direction on the outer circumference of the upper surface of the main body 21 and have a shape that protrudes upward. Permanent magnets 12 can be fitted between two faces of adjacent multiple protrusions 22 of the jig 2. The distance between two faces of the multiple protrusions 22 is designed to match the circumferential width of the permanent magnet 12. The distance between two faces of the multiple protrusions 22 can be manufactured with high precision by machining. By doing so, the fitting with the permanent magnet 12 can be set to the minimum gap, thus enabling high-precision phase alignment. Figure 6B is a top view of the multiple protrusions 22 of the jig 2 with the permanent magnet 12 fitted in. As shown in Figure 6B, the phase of the fitted permanent magnet 12 matches the reference phase of the jig 2. While it is preferable that the multiple protrusions 22 be integrally formed with the main body 21, they may be separate if the machining accuracy and assembly accuracy meet the target values.

[0040] Figure 6C is a cross-sectional view of the jig 2 with the rotor core 11 and multiple permanent magnets 12 fitted inside. Figure 6D is an enlarged view of Figure 6C. As shown in Figure 6C, the rotor core 11 is placed on the upper surface of the main body 21, and the shaft 111 of the rotor core 11 is inserted into the hole in the center of the main body 21. An internal spigot structure is provided in region R1 inside the hole in the center of the main body 21 to fix the inserted shaft 111 of the rotor core 11 in order to make the central axis of the jig 2 and the central axis of the rotor core 11 coaxial. Also, as shown in Figure 6D, a receiving surface for the permanent magnets 12 is provided in region R2 on the outer periphery of the upper surface of the main body 21 for determining the axial position of each of the multiple permanent magnets 12.

[0041] As described above, in the manufacturing method of the SPM rotor 1 of this embodiment, the jig 2 is used to accurately position the multiple permanent magnets 12 and the rotor core 11.

[0042] Next, we will explain countermeasures to address the problem (2) in the sleeve placement process of this embodiment, where the degree of coaxiality between the central axis of the rotor core 11 and the central axis of the sleeve 13 tends to deteriorate. The reason why the coaxiality tends to deteriorate is that each of the sleeves 13 and the multiple permanent magnets 12 must be fixed with adhesive 14, and therefore there is a gap for applying the adhesive 14. Since the sleeve 13 is connected to the permanent magnets 12 only through the adhesive 14, it is not supported by either the permanent magnets 12 or the rotor core 11, and is in a state where it can be displaced by the amount of the gap in the adhesive 14. Therefore, in the worst case, 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 in the adhesive 14, as described above using Figure 4B.

[0043] To solve this problem, it is effective to use another component to make the central axis of the rotor core 11 and the central axis of the sleeve 13 coaxial. Since thermal displacement between the permanent magnet 12 and the rotor core 11 is the problem, it is preferable to use a jig that is not affected by temperature differences. A jig 2 used for positioning multiple permanent magnets 12 is repurposed for this jig. After positioning the multiple permanent magnets 12, the same jig 2 is used to align the central axis of the sleeve 13 and the central axis of the rotor core 11 so that they are coaxial. Note that the jig 2 may also be used solely for the purpose of making the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0044] Figure 7 shows 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 in the manufacture of the SPM rotor 1 according to this embodiment. Figure 7A is a cross-sectional view of the jig 2 with the rotor core 11, multiple permanent magnets 12, and sleeve 13 fitted inside. As shown in Figure 7A, the jig 2 is provided with 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 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. Furthermore, the notch 23 is designed so that the central axis of the annular notch 23 is coaxial with the central axis of the hole in the center of the main body 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 center of the main body 21 are coaxial. In other words, the jig 2 makes the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0045] However, this method assumes 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] Furthermore, the jig 3 shown in Figure 7B may be used not only at the lower end of the sleeve 13, but also at the upper end of the sleeve 13, to make the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial. Figure 7B is a cross-sectional view of the jig 3 fitted into the rotor core 11, the multiple permanent magnets 12, and the sleeve 13. As shown in Figure 7B, the jig 3 has a substantially annular shape. The shaft 111 of the rotor core 11 is fitted into the hole in the center of the jig 3. The hole in the center of the jig 3 is designed so that the central axis of the rotor core 11 and the central axis of the jig 3 are coaxial. In addition, 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 center of the jig 3 and fixing the inner diameter surface on the upper end side of the sleeve 13 to 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 manufacturing method of the SPM rotor 1 of this embodiment, by using jigs 2 and 3, the central axis of the rotor core 11 and the central axis of the sleeve 13 can be made coaxial at the lower end and upper end of the sleeve 13, respectively. Furthermore, tilting of the sleeve 13 can be suppressed and the difference in coaxiality between the upper end and lower end of the sleeve 13 can be adjusted to the minimum.

[0048] (modified version) Next, a modified example of the manufacturing method of the SPM rotor 1 of the above-described embodiment will be explained. In the above embodiment, if 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 Figure 7). Below, a modified method for manufacturing the SPM rotor 1 that allows the central axis of the rotor core 11 and the central axis of the sleeve 13 to be coaxial in such a case will be described.

[0049] In the modified method for manufacturing the SPM rotor 1, jig 4 is used instead of jig 2, and jig 5 is used instead of jig 3. Figure 8 shows an example of the structure of the jigs (jig 4 and jig 5) used in the modified method for manufacturing the SPM rotor 1. Figure 8A is a cross-sectional view of the jig 4 with the rotor core 11, multiple permanent magnets 12, and sleeve 13 fitted inside. As shown in Figure 8A, the jig 4 has basically the same configuration as the jig 2, but instead of the annular notch 23, it has a projection 44. The projection 44 has an annular shape that follows the outer peripheral edge of the upper surface of the main body 21 and protrudes upward. The projection 44 is designed so that its inner diameter surface fixes the outer diameter surface of the sleeve 13. Here, the lower end surface of the sleeve 13 is fixed to the upper surface of the main body 21. In addition, the central axis of the annular projection 44 is designed to be coaxial with the central axis of the jig 4. Therefore, the jig 4 makes the central axis of the sleeve 13 and the central axis of the rotor core 11 coaxial.

[0050] Figure 8B is a cross-sectional view of the jig 5 fitted into the rotor core 11, the multiple 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 in the center of the jig 5. The hole in the center of the jig 5 is designed so that the central axis of the rotor core 11 and the central axis of the jig 5 are coaxial. The jig 5 also has an annular projection along the outer edge of its lower surface that protrudes downward. The inner diameter surface of this projection of the jig 5 is fixed to the outer diameter surface on the upper end side of the sleeve 13, and is designed so that the central axis of the sleeve 13 and the central axis of the jig 5 are coaxial. Therefore, the jig 5 makes 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 onto the shaft 111 of the rotor core 11 and the sleeve 13 after the sleeve 13 has been pushed all the way down to its lower end by a pressure pipe or the like. Alternatively, 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 circumferential surfaces of the multiple permanent magnets 12 hardens.

[0052] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0053] 1 Surface-mounted magnetic rotor (SPM), 2, 3, 4, 5 Fixtures, 11 Rotor core, 12 Permanent magnet, 13 Sleeve, 14 Adhesive, 21 Main body, 22 Protruding part, 23 Notch, 44 Protruding part, 111 Shaft

Claims

1. A method for manufacturing a surface magnet type rotor comprising a rotor core, a plurality of permanent magnets attached to the outer surface of the rotor core in a circumferential direction, and a sleeve attached to the plurality of permanent magnets so as to cover the outer surface of the plurality of permanent magnets, A jig comprising a main body having a substantially cylindrical shape, a plurality of protrusions arranged circumferentially on the outer circumference of the upper surface of the main body and projecting upward, and an annular notch provided along the outer peripheral edge of the upper surface of the main body, wherein the notch is designed so that its central axis is coaxial with the central axis of the hole in the center of the main body, The process involves placing the rotor core on the upper surface of the main body of the jig, inserting the shaft of the rotor core into the hole in the center of the main body, and fitting each of the multiple permanent magnets attached to the outer surface of the rotor core in a circumferential direction between the multiple protrusions adjacent to each other. A step of applying adhesive to the outer surface of the plurality of permanent magnets or the inner surface of the sleeve, The process includes inserting the rotor core and the plurality of permanent magnets into the sleeve, fitting the lower end of the sleeve into the notch of the jig, and fixing the outer circumferential surface of each of the plurality of permanent magnets to the inner diameter surface of the sleeve with the adhesive. A method for manufacturing a surface-magnetic rotor.

2. The central hole in the main body of the jig is designed so that the central axis of the hole in the main body is coaxial with the central axis of the rotor core shaft. A 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 attached to the outer surface of the rotor core in a circumferential direction, and a sleeve attached to the plurality of permanent magnets so as to cover the outer surface of the plurality of permanent magnets, A main body having a roughly cylindrical shape, Multiple protrusions are arranged in a circumferential direction on the outer periphery of the upper surface of the main body and protrude upward, The main body comprises an annular notch provided along the outer peripheral edge of the upper surface, The notch is designed such that its central axis is coaxial with the central axis of the hole in the center of the main body. The rotor core is placed on the upper surface of the main body, and the shaft of the rotor core is inserted into the hole in the center of the main body. Each of the plurality of permanent magnets is fitted between the plurality of adjacent protrusions, With the rotor core and the plurality of permanent magnets inserted inside the sleeve, the lower end of the sleeve is fitted into the notch. A jig for manufacturing surface-magnetic rotors.

4. The central hole in the main body of the jig is designed so that the central axis of the hole in the main body is coaxial with the central axis of the rotor core shaft. A jig for manufacturing a surface magnet type rotor as described in claim 3.

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