Rotor manufacturing method

Abstract

To provide a manufacturing method of a rotor which can manufacture a plurality of kinds of rotors with high production efficiency.SOLUTION: A manufacturing method of a rotor 10 arranges a first core having a plurality of magnet storage holes 13 between a first mold part 20 and a second mold part 50 arranged so as to face each other, and fills the respective magnet storage holes 13 with resin materials in a state where magnets 14 are stored in the magnet storage holes 13 and fixes the magnets 14. The first mold part 20 has a workpiece spacer 40 arranged so as to be adjacent to the first core, and a base part 21 arranged so as to be adjacent to an opposite side to the first core side in the workpiece spacer 40. When a rotor 10 is manufactured using a second core 11B having a length in an opposite direction Z at which the first mold part 20 and the second mold part 50 face each other shorter than that of the first core instead of the first core, an adjustment member 30 for compensating a difference of lengths between the first core and the second core 11B in the opposite direction Z between the workpiece spacer 40 and the base part 21 is arranged.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a rotor of an interior permanent magnet motor.

Background Art

[0002] The rotor of an interior permanent magnet motor has a core with a structure in which a plurality of core pieces are laminated. The core is provided with a plurality of magnet accommodation holes penetrating in the lamination direction of the core pieces. Each of the magnet accommodation holes fixes the magnet by accommodating the magnet therein and then filling the hole with a resin material.

[0003] As an apparatus for manufacturing such a rotor, for example, the one disclosed in Patent Document 1 has been conventionally known. The rotor manufacturing apparatus described in Patent Document 1 includes a first mold part and a second mold part that are disposed opposite to each other with the core interposed therebetween. One of the first mold part and the second mold part has a filling port for filling the resin material. In this manufacturing apparatus, the core, in which a magnet is accommodated in each of the plurality of magnet accommodation holes, is disposed between the first mold part and the second mold part. Then, in this state, each of the plurality of magnet accommodation holes is filled with a resin material, thereby fixing the magnets.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] The cores used in rotor manufacturing come in several types, each with a different number of stacked iron core pieces. In other words, there are several types of cores with different lengths in the stacking direction of the iron core pieces. Manufacturing multiple types of rotors using these cores of different lengths requires either preparing dedicated manufacturing equipment for each core used, or changing the settings and conditions of the manufacturing equipment each time to suit the core being used. Such limitations on manufacturing equipment are one of the factors that lead to a decrease in the production efficiency of rotor manufacturing. [Means for solving the problem]

[0006] The following describes the means and effects of solving the above problems. A rotor manufacturing method that solves the above problems is a rotor manufacturing method in which a first core having a plurality of magnet housing holes is placed between a first mold part and a second mold part arranged opposite to each other, and a magnet is housed in each of the plurality of magnet housing holes, and a rotor is manufactured by filling each of the plurality of magnet housing holes with a resin material to fix the magnet, wherein the first mold part has a work spacer arranged adjacent to the first core and a base member arranged adjacent to the work spacer on the opposite side from the first core, and when the rotor is manufactured using a second core in place of the first core, which has a shorter length in the opposing direction, the direction in which the first mold part and the second mold part face each other, an adjustment member is placed between the work spacer and the base member to compensate for the difference in length between the first core and the second core in the opposing direction.

[0007] According to the above manufacturing method, when manufacturing a rotor using the second core, the manufacturing equipment used to manufacture rotors using the first core can be used as is by placing an adjustment member between the work spacer and the base member. Therefore, multiple types of rotors using cores of different lengths can be manufactured without having to prepare separate manufacturing equipment for manufacturing rotors using the second core or change the settings of the rotor manufacturing equipment between using the first core and using the second core. Consequently, multiple types of rotors can be manufactured with high production efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a rotor manufactured by a manufacturing method according to one embodiment. [Figure 2] This is a cross-sectional view of a rotor manufactured using the first core. [Figure 3] This is a cross-sectional view of a rotor manufactured using the second core. [Figure 4] This is a cross-sectional view showing the state when the first core is set in the manufacturing equipment. [Figure 5] This is a cross-sectional view showing the state when the second core is set in the manufacturing equipment. [Figure 6] Figure 5 is an exploded view. [Figure 7] This is a plan view showing the positional relationship between the core and the adjustment member. [Figure 8] This is a plan view showing the positional relationship between the core and the work spacer. [Figure 9] This is a plan view of the adjustment member in the modified example. [Figure 10] This is a cross-sectional view taken along the line 10-10 in Figure 9. [Figure 11] Figure 10 is a cross-sectional view showing the state when the adjustment member is turned upside down. [Modes for carrying out the invention]

[0009] An embodiment of the rotor manufacturing method will be described below with reference to the drawings. <Rotor> As shown in Figure 1, the rotor 10 includes a core 11 formed by laminating a plurality of iron core pieces 12 made of electromagnetic steel sheets. That is, the core 11 is composed of a laminate formed by laminating a plurality of iron core pieces 12. The core 11 has a central hole 11a and a plurality (20 in this embodiment) of magnet housing holes 13 located on the outer circumference of the central hole 11a and spaced apart from each other in the circumferential direction. The central hole 11a and each magnet housing hole 13 extend along the axis C of the core 11 in a manner that penetrates the core 11. The cross-sectional shape of each magnet housing hole 13 is a shape that extends in the circumferential direction.

[0010] A pair of protrusions 11b are provided along the axis C on the inner circumferential surface of the central hole 11a, facing each other in the radial direction of the core 11. A magnet 14 is housed in each magnet housing hole 13. The magnet 14 is in the shape of a rectangular parallelepiped extending along the axis C. The inside of each magnet housing hole 13 is filled with a resin material 16 for fixing the magnet 14. It is preferable to use a thermosetting resin such as epoxy resin as the resin material 16.

[0011] In this embodiment, two types of rotors 10 are manufactured using the same manufacturing apparatus. As shown in Figure 2, one of the two types of rotors 10 is rotor 10A, in which the first core 11A is used as the core 11. As shown in Figure 3, the other of the two types of rotors 10 is rotor 10B, in which the second core 11B is used as the core 11.

[0012] As shown in Figures 2 and 3, the second core 11B is a core 11 in which the number of stacked iron core pieces 12 is reduced compared to the first core 11A. In other words, the second core 11B is a core 11 that is shorter in the direction in which the axis C extends than the first core 11A. Therefore, in the rotor 10B, the length of each magnet housing hole 13 and magnet 14 in the direction in which the axis C extends is shorter than that of the rotor 10A.

[0013] <Manufacturing equipment> As shown in Figure 4, the manufacturing apparatus includes a first mold part 20 and a second mold part 50 that are disposed opposite to each other. When manufacturing the rotor 10A by the manufacturing apparatus, the first core 11A is disposed between the first mold part 20 and the second mold part 50.

[0014] <First mold part> As shown in Figure 4, the first mold part 20 includes a mold main body 20A, a support member 20B, and a work spacer 40. The first mold part 20 has a structure in which the support member 20B (specifically, the base part 21) and the work spacer 40 are stacked in the opposing direction Z of the first mold part 20 and the second mold part 50. The opposing direction Z coincides with the extending direction of the axis C of the first core 11A (core 11) disposed between the first mold part 20 and the second mold part 50.

[0015] <Support member> As shown in Figure 1, Figure 4 and Figure 7, the support member 20B is placed on the mold main body 20A. The support member 20B includes a substantially rectangular plate-shaped base part 21 and a cylindrical post part 22 that protrudes upward from the central portion of the base part in a plan view. In the present embodiment, the base member is constituted by the base part 21 of the support member 20B.

[0016] On the outer peripheral surface of the post part 22, a pair of engaging grooves 22b with which the respective protrusions 11b of the first core 11A engage are provided along the axis C. By inserting the respective protrusions 11b of the first core 11A into the respective engaging grooves 22b of the post part 22, the positioning of the first core 11A relative to the post part 22 in the circumferential direction is performed. At the distal end portion of the post part 22 (the upper end portion in Figure 4), four fitting pins 22 each having a columnar shape protruding toward the distal end side (upper side) are provided at equal intervals in the circumferential direction.

[0017] <Work spacer> As shown in Figures 4 and 8, the work spacer 40 is substantially rectangular in shape. The work spacer 40 is provided on the base 21 of the support member 20B. The work spacer 40 has its upper surface 41 adjacent to the first core 11A and its lower surface 42 adjacent to the base 21. Therefore, the base 21 is positioned adjacent to the work spacer 40 on the side opposite to the first core 11A.

[0018] In other words, the work spacer 40 is provided in such a manner that the lower surface 42 of the work spacer 40 and the upper surface of the base 21 of the support member 20B are aligned. A through hole 40a, which is approximately circular in plan view, is provided in the center of the work spacer 40 in plan view. The post portion 22 of the support member 20B is inserted through the through hole 40a.

[0019] As shown in Figures 4, 7, and 8, the inner circumferential surface of the through hole 40a is provided with a pair of engaging projections 40b extending along the axis C. Each engaging projection 40b engages with each engaging groove 22b of the post portion 22. In the manufacturing apparatus of this embodiment, the circumferential positioning of the work spacer 40 relative to the post portion 22 is achieved by the engagement of the engaging grooves 22b of the post portion 22 with the engaging projections 40b of the work spacer 40.

[0020] <Float pin> As shown in Figures 4 and 8, multiple float pins 41a are provided at several locations (40 locations in this embodiment) on the upper surface 41 of the work spacer 40, which is the surface on the first core 11A side. Each float pin 41a has a frustoconical shape that tapers towards its tip. The float pins 41a are individually provided in the parts corresponding to each of the multiple magnet housing holes 13.

[0021] Two float pins 41a are provided in a manner that they are aligned along the longitudinal direction of the cross-section of one magnet housing hole 13, corresponding to the portion of one magnet housing hole 13. Each float pin 41a is provided in a manner that is point-symmetric with respect to axis C as the center of symmetry, and also in a manner that is line-symmetric with respect to a line perpendicular to axis C as the axis of symmetry. The ends of the float pins 41a support the ends of the magnets 14 inside the magnet housing hole 13 by their protruding ends. In this case, the work spacer 40 closes the opening 13a on the work spacer 40 side of the magnet housing hole 13.

[0022] <Manufacturing equipment> As shown in Figures 4 and 5, when the rotor 10B is manufactured using the above manufacturing apparatus, the second core 11B is placed between the first mold section 20 and the second mold section 50 in place of the first core 11A. The length of the second core 11B in the opposing direction Z, which is the direction in which the first mold section 20 and the second mold section 50 face each other, is shorter than that of the first core 11A. When the second core 11B is placed between the first mold section 20 and the second mold section 50, the adjustment member 30 is placed between the work spacer 40 and the base 21 of the support member 20B.

[0023] <Adjustment component> As shown in Figures 4 and 5, the adjustment member 30 is a member that compensates for the difference in length between the first core 11A and the second core 11B in the opposing direction Z. That is, the adjustment member 30 is configured so that the sum of the length of the second core 11B and the length of the adjustment member 30 in the opposing direction Z is equal to the length of the first core 11A in the opposing direction Z.

[0024] As shown in Figures 5 to 7, the adjustment member 30 is positioned between the work spacer 40 and the base 21 of the support member 20B. The adjustment member 30 has a polygonal shape when viewed from the opposing direction Z. The adjustment member 30 in this embodiment is substantially rectangular in shape. The adjustment member 30 is positioned such that its lower surface 32 is aligned with the upper surface of the base 21 of the support member 20B and its upper surface 31 is aligned with the lower surface 42 of the work spacer 40.

[0025] A through-hole 30a, which is approximately circular in plan view, is provided in the center of the adjustment member 30. The post portion 22 of the support member 20B is inserted through the through-hole 30a. A pair of engaging projections 30b extending along the axis C are provided on the inner circumferential surface of the through-hole 30a. Each engaging projection 30b engages with each engaging groove 22b of the post portion 22.

[0026] In the manufacturing apparatus of this embodiment, the circumferential positioning of the adjustment member 30 relative to the post portion 22 is achieved by the engagement of the engagement groove 22b of the post portion 22 and the engagement projection 30b of the adjustment member 30. In this case, the adjustment member 30 is configured such that the entire second core 11B overlaps with it in the opposing direction Z. That is, the adjustment member 30 is configured to cover the entire second core 11B in the opposing direction Z.

[0027] <Second mold section> As shown in Figures 5 and 6, the second mold section 50 comprises a mold body 50A and a cal plate 50B. The cal plate 50B is plate-shaped and interposed between the mold body 50A and the core 11. The cal plate 50B is provided with a plurality of fitting holes 51 corresponding to the fitting pins 23 of the post section 22. The cal plate 50B is positioned on the core 11 so as to close the opening 13b on the side of the magnet housing hole 13 furthest from the work spacer 40 (upper side in Figure 5). The lower surface 52 of the cal plate 50B is in contact with the upper surface of the core 11.

[0028] The Calplate 50B has a passage 53 for supplying resin material 16 (see Figure 1) to the opening 13b of the magnet housing hole 13. The passage 53 has a plurality of branch passages 53a and a plurality of gate portions 53b, each corresponding to a plurality of magnet housing holes 13. The plurality of branch passages 53a extend radially from a central position on the axis C on the upper surface of the Calplate 50B.

[0029] The gate portion 53b extends along the axis C, penetrating the Calplate 50B in the thickness direction. One end of the gate portion 53b is connected to the end of the branch passage 53a that is farther from the central position. The other end of the gate portion 53b is a filling port 53c that opens on the lower surface 52 of the Calplate 50B. In this embodiment, resin material 16 (see Figure 1) is filled into each of the multiple magnet housing holes 13 through the filling port 53c.

[0030] <Manufacturing method> First, let's explain the manufacturing method of rotor 10A. As shown in Figure 4, when manufacturing the rotor 10A using a manufacturing apparatus, first, the work spacer 40 is assembled to the support member 20B by inserting the post portion 22 of the support member 20B into the through hole 40a of the work spacer 40. Next, the first core 11A is attached to the support member 20B by inserting the post portion 22 of the support member 20B into the central hole 11a of the first core 11A. Subsequently, the corresponding magnets 14 are inserted into each magnet housing hole 13 of the first core 11A.

[0031] At this time, each magnet 14 is supported on its lower surface by the tip of a float pin 41a provided on the upper surface 41 of the work spacer 40. As a result, each magnet 14 is held at a position above the upper surface 41 of the work spacer 40. Next, the fitting pins 23 of the post portion 22 are fitted into each fitting hole 51 of the cal plate 50B, thereby bringing the lower surface 52 of the cal plate 50B into contact with the upper surface of the first core 11A and performing mold closing. As a result, the first core 11A is positioned between the base portion 21 of the support member 20B and the cal plate 50B.

[0032] Next, resin material 16 is filled into each magnet housing hole 13 of the first core 11A via the resin supply passage (not shown) of the mold body 50A and the passage 53 of the calplate 50B. Subsequently, the entire manufacturing apparatus is heated by a heating device (not shown). As a result, the thermosetting resin material 16 is heat-cured, and the magnets 14 are fixed to the first core 11A.

[0033] Next, the mold is opened to remove the rotor 10A (more specifically, the first core 11A to which the magnet 14 is fixed) from the manufacturing apparatus. That is, the second mold section 50 is removed from the support member 20B. After that, the rotor 10A is removed from the support member 20B to obtain the rotor 10A.

[0034] Next, we will explain the manufacturing method of the rotor 10B. As shown in Figures 5 and 6, when manufacturing the rotor 10B using a manufacturing apparatus, first, the adjustment member 30 is assembled to the support member 20B by inserting the post portion 22 of the support member 20B through the through hole 30a of the adjustment member 30. Next, the work spacer 40 is assembled to the support member 20B by inserting the post portion 22 of the support member 20B through the through hole 40a of the work spacer 40. Subsequently, the second core 11B is attached to the support member 20B by inserting the post portion 22 of the support member 20B into the central hole 11a of the second core 11B.

[0035] At this time, the adjustment member 30 compensates for the difference in length between the first core 11A and the second core 11B in the opposing direction Z. As a result, the height position of the upper surface of the second core 11B becomes the same as the height position of the upper surface of the first core 11A when the first core 11A is attached to the support member 20B without the adjustment member 30 being assembled to the support member 20B. Next, the corresponding magnets 14 are inserted into each magnet housing hole 13 of the second core 11B.

[0036] At this time, each magnet 14 is supported on its lower surface by the tip of a float pin 41a provided on the upper surface 41 of the work spacer 40. As a result, each magnet 14 is held at a position above the upper surface 41 of the work spacer 40. Next, the fitting pins 23 of the post portion 22 are fitted into each fitting hole 51 of the cal plate 50B, thereby bringing the lower surface 52 of the cal plate 50B into contact with the upper surface of the second core 11B and performing mold closing. As a result, the second core 11B is positioned between the base portion 21 of the support member 20B and the cal plate 50B.

[0037] Next, resin material 16 is filled into each magnet housing hole 13 of the second core 11B via the resin supply passage (not shown) of the mold body 50A and the passage 53 of the calplate 50B. Subsequently, the entire manufacturing apparatus is heated by a heating device (not shown). As a result, the thermosetting resin material 16 is heat-cured, and the magnets 14 are fixed to the second core 11B.

[0038] Next, the mold is opened to remove the rotor 10B (more specifically, the second core 11B to which the magnet 14 is fixed) from the manufacturing apparatus. That is, the second mold section 50 is removed from the support member 20B. After that, the rotor 10B is removed from the support member 20B to obtain the rotor 10B.

[0039] Thus, when manufacturing the rotor 10B using the second core 11B, the manufacturing equipment used to manufacture the rotor 10A using the first core 11A can be used as is by placing the adjustment member 30 between the work spacer 40 and the base 21 of the support member 20B. Therefore, multiple types of rotors 10 using cores 11 of different lengths can be manufactured without having to prepare separate manufacturing equipment for manufacturing the rotor 10B using the second core 11B or change the settings of the rotor 10 manufacturing equipment between using the first core 11A and using the second core 11B. Consequently, multiple types of rotors 10 can be manufactured with high production efficiency.

[0040] According to the embodiments described in detail above, the following effects are achieved. (1) In the method for manufacturing the rotor 10, when the rotor 10 is manufactured using a second core 11B, which has a shorter length in the opposing direction Z than the first core 11A, instead of the first core 11A, the following is done. That is, an adjustment member 30 is placed between the work spacer 40 and the base 21 of the support member 20B to compensate for the difference in length between the first core 11A and the second core 11B in the opposing direction Z.

[0041] According to the above manufacturing method, when manufacturing the rotor 10 using the second core 11B, the manufacturing equipment used to manufacture the rotor 10 using the first core 11A can be used as is by placing the adjustment member 30 between the work spacer 40 and the base 21. Therefore, multiple types of rotors 10 using cores 11 with different lengths in the opposing direction Z can be manufactured without having to prepare separate manufacturing equipment for manufacturing the rotor 10 using the second core 11B or change the settings of the rotor manufacturing equipment between using the first core 11A and using the second core 11B. Consequently, multiple types of rotors 10 can be manufactured with high production efficiency.

[0042] (2) In the method for manufacturing the rotor 10, the adjustment member 30 is configured such that the entirety of the second core 11B overlaps in the opposing direction Z. According to the above manufacturing method, the entire second core 11B can be covered by the adjustment member 30 in the opposing direction Z, so the second core 11B can be stably supported by the adjustment member 30 via the work spacer 40.

[0043] (3) In the method for manufacturing the rotor 10, the adjustment member 30 has a polygonal shape when viewed from the opposing direction Z. According to the above manufacturing method, the curved portion is eliminated from the contour of the adjustment member 30. Therefore, the adjustment member 30 can be manufactured more easily compared to cases where the adjustment member 30 has a circular or elliptical shape with a contour composed of curves.

[0044] (Example of change) The above embodiment can be implemented with the following modifications. Furthermore, the above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0045] As shown in Figures 9 to 11, the upper surface 31 of the adjustment member 30 may be provided with a plurality of protrusions 60, and the upper surface of the base 21 of the support member 20B may be provided with a plurality of receiving recesses 61 that accommodate the plurality of protrusions 60 when the adjustment member 30 is turned upside down. In this way, a single adjustment member 30 can compensate for the difference between the length in the opposing direction Z of two types of second cores 11B, which are shorter in the opposing direction Z than the first core 11A and have different lengths, and the length in the opposing direction Z of the first core 11A.

[0046] The adjustment member 30 does not necessarily have to be polygonal when viewed from the opposing direction Z. That is, the adjustment member 30 may be circular or elliptical when viewed from the opposing direction Z.

[0047] The engaging projection 30b on the adjustment member 30 may be omitted. In other words, the adjustment member 30 does not need to be positioned circumferentially with respect to the post portion 22. The adjustment member 30 does not necessarily have to be configured so that the entire second core 11B overlaps in the opposing direction Z. That is, the adjustment member 30 may be configured so that, for example, a part of the second core 11B overlaps in the opposing direction Z. [Explanation of Symbols]

[0048] 10, 10A, 10B… Rotor 11... Core 11A…First core 11a...Center hole 11b...projection 11B...Second core 12… Iron core piece 13…Magnet housing hole 13a, 13b...opening 14…Magnets 16… Resin material 20…1st mold part 20A... type main unit 20B...Support member 21...Base portion constituting the base member 22…Post Department 22b…Engagement groove 23…Mating pin 30...Adjustment parts 30a...Through hole 30b…Engagement protrusion 31…Top surface 32…Bottom surface 40…Work Spacer 40a...Through hole 40b…Engagement protrusion 41…Top surface 41a... Float pin 42…Bottom surface 50…Second mold part 50A... type main unit 50B... Calplate 51…Matching hole 52…Bottom surface 53…Passageway 53a... Branching passage 53b...Gate section 53c…Filling port 60… protrusion 61… Storage recess C…Axis line Z... Opposite direction

Claims

1. A method for manufacturing a rotor, comprising: arranging a first core having a plurality of magnet housing holes between a first mold portion and a second mold portion arranged opposite each other; housing a magnet in each of the plurality of magnet housing holes; and then filling each of the plurality of magnet housing holes with a resin material to fix the magnet in place, The first mold portion includes a work spacer positioned adjacent to the first core and a base member positioned adjacent to the work spacer on the side opposite to the first core. When manufacturing the rotor using a second core in place of the first core, the second core having a shorter length in the opposing direction (the direction in which the first mold portion and the second mold portion face each other) than the first core, an adjustment member is placed between the work spacer and the base member to compensate for the difference in length between the first core and the second core in the opposing direction, thereby making the position of the second mold portion side of the second core when the second core is sandwiched between the first mold portion and the second mold portion and the mold is closed the same as the position of the second mold portion side of the first core when the first core is sandwiched between the first mold portion and the second mold portion and the mold is closed without the adjustment member being placed between the work spacer and the base member. The adjustment member has an upper surface and a lower surface opposite to the upper surface, and the upper surface is provided with a plurality of protrusions. The base member has a plurality of receiving recesses that accommodate the plurality of protrusions when the adjustment member is inverted so that the upper and lower surfaces are reversed. A rotor manufacturing method characterized in that, when manufacturing the rotor using one of two types of second cores having different lengths in the opposing directions, when using the second core with the shorter length in the opposing direction of the two types of second cores, the adjustment member is placed between the work spacer and the base member without flipping the adjustment member over and without housing the multiple protrusions in the multiple housing recesses, and when using the other second core with the longer length in the opposing direction of the two types of second cores, the adjustment member is placed between the work spacer and the base member with the upper and lower surfaces reversed and housing the multiple protrusions in the multiple housing recesses, thereby compensating for the difference between the lengths in the opposing directions of each of the two types of second cores and the length in the opposing direction of the first core with a single adjustment member.

2. The method for manufacturing a rotor according to claim 1, characterized in that the adjusting member is configured such that the entirety of the second core overlaps in the opposing direction.

3. The method for manufacturing a rotor according to claim 1 or 2, characterized in that the adjusting member has a polygonal shape when viewed from the opposing direction.

4. A method for manufacturing a rotor, comprising: arranging a first core having a central hole and a plurality of magnet housing holes between a first mold portion and a second mold portion arranged opposite each other, housing magnets in each of the plurality of magnet housing holes, and then filling each of the plurality of magnet housing holes with a resin material to fix the magnets, The first mold portion comprises a work spacer positioned adjacent to the first core and having a through hole, a base portion positioned adjacent to the work spacer on the side opposite to the first core, and a post portion that protrudes from the base portion toward the second mold portion and is inserted into the through hole and the central hole. When manufacturing the rotor using a second core in place of the first core, the second core having a shorter length in the opposing direction (the direction in which the first mold portion and the second mold portion face each other) than the first core, an adjustment member is placed between the work spacer and the base portion to compensate for the difference in length between the first core and the second core in the opposing direction. The adjustment member has an upper surface and a lower surface opposite to the upper surface, and the upper surface is provided with a plurality of protrusions. The base has a plurality of receiving recesses that accommodate a plurality of protrusions when the adjustment member is turned upside down so that its upper and lower surfaces are reversed. A rotor manufacturing method characterized in that, when manufacturing the rotor using one of two types of second cores having different lengths in the opposing directions, when using the second core with the shorter length in the opposing direction of the two types of second cores, the adjustment member is placed between the work spacer and the base without flipping the adjustment member over and without housing the multiple protrusions in the multiple housing recesses, and when using the other second core with the longer length in the opposing direction of the two types of second cores, the adjustment member is placed between the work spacer and the base with the upper and lower surfaces reversed and housing the multiple protrusions in the multiple housing recesses, thereby compensating for the difference between the lengths in the opposing directions of each of the two types of second cores and the length in the opposing direction of the first core with a single adjustment member.

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