Method and device for manufacturing rotor

Abstract

The present invention provides a method for manufacturing a rotor whereby an annular member can be attached stably to the outer circumference of a rotor core. In this method for manufacturing a rotor, a columnar rotor core 3 is disposed inside an annular member 5, a radial gap 41 is expanded between the annular member 5 and an axial end 3b of the rotor core 3, a resin 13 is injected between the annular member 5 and the rotor core 3 from the expanded gap 41, the annular member 5 is pressed radially outward with respect to the rotor core 3, and the resin 13 is cured in a state with the annular member 5 pressed by the resin 13.

Description

Method and apparatus for manufacturing a rotor

[0001] The present invention relates to a method and an apparatus for manufacturing a rotor in which an annular member is attached to a columnar rotor core.

[0002] As a conventional rotor, for example, as disclosed in Patent Document 1, there is a rotor in which an annular member is attached to the outer periphery of a columnar rotor core formed by laminating a plurality of plate-like core pieces.

[0003] Attachment of the annular member to the rotor core is preferably performed by interference fitting such as press-fitting or shrink-fitting in order to ensure strength. However, depending on the material of the annular member, it hardly expands thermally or has a limit in the interference allowance, so the annular member could not be stably attached to the rotor core.

[0004] Japanese Patent No. 6220328

[0005] The problem to be solved is that the annular member cannot be stably attached to the rotor core.

[0006] The present invention provides a method for manufacturing a rotor, which comprises disposing a columnar rotor core inside an annular member, expanding a radial gap between the annular member and an axial end portion of the rotor core, injecting a resin from the expanded gap between the annular member and the rotor core to press the annular member radially outward against the rotor core, and curing the resin while the annular member is being pressed by the resin.

[0007] The present invention also provides a manufacturing apparatus for a rotor, which comprises a fitting member that is disposed on a rotor in which an axial end portion of the annular member protrudes in the axial direction with respect to an axial end portion of a columnar rotor core disposed inside the annular member and that fits radially into an inner periphery of the end portion of the annular member, a drive portion that expands the fitting member in the radial direction, and a resin injector that injects a resin from a radial gap between the end portion of the rotor core expanded in the radial direction by the expansion of the fitting member and the annular member to press the annular member radially outward against the rotor core.

[0008] Furthermore, the present invention provides a rotor manufacturing apparatus comprising: a rotor having a columnar rotor core arranged inside an annular member; abutment member positioned to abut the axial end of the annular member in the axial direction; and a resin injection machine that injects resin into the radial gap between the annular member and the rotor core, thereby pressing the annular member radially outward relative to the rotor core. The resin injection machine displaces the end of the annular member radially relative to the axial end of the rotor core by injecting the resin. The abutment member allows the displacement of the end of the annular member relative to the end of the rotor core by elastic deformation.

[0009] According to the present invention, an annular member can be stably attached to the outer circumference of the rotor core.

[0010] Figure 1 is a schematic perspective view showing an example of a rotor according to Embodiment 1 of the present invention. Figure 2 is a perspective view showing the manufacturing apparatus for the rotor of Figure 1. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. Figure 4 is a perspective cross-sectional view taken along line A-B in Figure 2. Figure 5 is a plan view of the manufacturing apparatus for the rotor of Figure 2 with the upper mold omitted. Figures 6(A) and 6(B) are cross-sectional views of the rotor core of the rotor of Figure 1 before and after placement inside the annular member, with Figure 6(A) showing the state before placement and Figure 6(B) showing the state after placement. Figure 7 is an enlarged cross-sectional view showing the gap between the rotor core and the annular member in Figure 6(B). Figure 8 is a cross-sectional view showing the rotor in a temporarily assembled state placed on the lower mold according to the rotor manufacturing method of Embodiment 1. Figure 9 is a cross-sectional view showing the rotor in a temporarily assembled state on the lower mold in Figure 8 with the upper fitting member placed on top. Figure 10 is a cross-sectional view showing the upper mold placed on top of the upper fitting member in Figure 9. Figure 11 is a cross-sectional view showing the rotor in a pre-assembled state being pressurized between the upper and lower molds of Figure 10. Figure 12 is an enlarged cross-sectional view showing the expansion of the gap in the pre-assembled rotor of Figure 11. Figure 13 is an enlarged cross-sectional view showing the injection of resin into the gap in the pre-assembled rotor of Figure 12. Figure 14 is a perspective view showing a part of the rotor manufacturing apparatus according to a modified example of Example 1, with the upper mold omitted. Figure 15 is a perspective cross-sectional view showing a part of the rotor manufacturing apparatus according to another modified example of Example 1, with the upper mold omitted. Figure 16 is a cross-sectional view showing the rotor manufacturing apparatus according to Example 2 of the present invention.

[0011] In one embodiment of the rotor 1 manufacturing method, a columnar rotor core 3 is placed inside an annular member 5, and a radial gap 41 is expanded between the annular member 5 and the axial end 3b of the rotor core 3. Resin 13 is injected between the annular member 5 and the rotor core 3 through the expanded gap 41, pressing the annular member 5 radially outward relative to the rotor core 3. Then, the resin 13 is hardened while the annular member 5 is pressed with the resin 13.

[0012] The gap 41 can be expanded between the annular member 5 and one axial end 3b or both ends 3b of the rotor core 3. When expanding the gap 41 between the annular member 5 and both ends 3b of the rotor core 3, the resin 13 can be injected from either side of the expanded gap 41.

[0013] The timing for starting to expand the gap 41 may be either before or during the injection of the resin 13.

[0014] In an embodiment in which the gap 41 is expanded before the injection of resin 13, the annular member 5 may have an axial end 5a that protrudes axially from the end 3b of the rotor core 3 when the rotor core 3 is placed inside it. In this case, the end 5a of the annular member 5 is displaced radially outward to expand the gap 41.

[0015] In this embodiment, the fitting members 21 and 23 may be fitted radially to the inner circumference of the end portion 5a of the annular member 5, and the fitting members 21 and 23 may be expanded in a resizable diameter to widen the gap 41.

[0016] In one embodiment, the fitting members 21 and 23 consist of a plurality of movable parts 37 that can move in the radial direction, and their diameter may be expanded by the radial movement of the movable parts 37. In another embodiment, the fitting members 21 and 23 consist of ring-shaped members, and their diameter may be expanded by radial expansion.

[0017] In an embodiment in which the gap 41 is expanded during the injection of resin 13, the axial end 5a of the annular member 5 may be displaced radially outward relative to the end 3b of the rotor core 3 by injecting resin 13 into the gap 41.

[0018] In this embodiment, when expanding the gap 41, the abutment members 45 and 47 may be abutted against the axial end 5a of the annular member 5 in the axial direction. In this case, the abutment members 45 and 47 allow displacement of the end 5a of the annular member 5 relative to the end 3b of the rotor core 3 due to elastic deformation when the resin 13 is injected into the gap 41.

[0019] A rotor 1 manufacturing apparatus 15 in one embodiment comprises fitting members 21 and 23, a drive unit 25, and a resin injection machine 27. The fitting members 21 and 23 are positioned relative to the rotor 1 and fit radially onto the inner circumference of the end 5a of the annular member 5. The drive unit 25 expands the fitting members 21 and 23 radially outward. The resin injection machine 27 injects resin 13 into the gap 41 expanded by the expansion of the fitting members 21 and 23, pressing the annular member 5 radially outward relative to the rotor core 3.

[0020] The fitting members 21 and 23 preferably have a flow path 39 for the resin 13 that leads to the gap 41 between the end portion 3b of the rotor core 3 and the annular member 5.

[0021] The rotor 1 manufacturing apparatus 15 includes an upper mold 17 and a lower mold 19 that pressurize the rotor 1 from above and below, and the drive unit 25 may be a cam unit provided between the fitting members 21, 23 and the upper mold 17 or lower mold 19, which presses the fitting members 21, 23 radially outward by the pressure from the upper mold 17 and lower mold 19 to expand their diameter.

[0022] In one embodiment, the fitting members 21 and 23 are provided with a plurality of movable parts 37 that can move in the radial direction, and the drive unit 25 may move the movable parts 37 outward in the radial direction.

[0023] In another embodiment, the fitting members 21 and 23 may be ring-shaped members. In this case, the drive unit 25 expands the fitting members 21 and 23 in the radial direction.

[0024] In another embodiment, the rotor 1 manufacturing apparatus 15 includes abutment members 45 and 47 instead of fitting members 21 and 23. The abutment members 45 and 47 abut against the axial end 5a of the annular member 5 in the axial direction.

[0025] In this embodiment, the resin injection machine 27 displaces the end 5a of the annular member 5 radially outward relative to the end 3b of the rotor core 3 by injecting the resin 13. The abutment members 45 and 47 allow the displacement of the end 5a of the annular member 5 relative to the end 3b of the rotor core 3 by elastic deformation.

[0026] In this embodiment, the rotor 1 manufacturing apparatus 15 may also include inner members 49 and 51 and a flow path 39 for the resin 13. The inner members 49 and 51 are arranged radially inside the abutment members 45 and 47. The flow path 39 is partitioned between the abutment members 45 and 47 and the inner members 49 and 51, and leads to the gap 41 between the end 3c of the rotor core 3 and the end 5a of the annular member 5.

[0027] [Rotor Structure] Figure 1 is a schematic perspective view showing an example of a rotor according to Embodiment 1 of the present invention.

[0028] The rotor 1 in Figure 1, together with the stator, constitutes a rotating electric machine. The rotor 1 comprises a rotor core 3 and an annular member 5. This rotor 1 is an IPM (Internal Permanent Magnet) rotor in which magnets (not shown) are housed in magnet housing holes 7 of the rotor core 3. However, the rotor 1 may not have magnet housing holes 7. For example, the rotor 1 may be an SPM (Surface Permanent Magnet) rotor in which magnets are arranged on the outer circumferential surface of the rotor core 3. Alternatively, the rotor 1 may be a rotor without magnets.

[0029] In this embodiment, the rotor core 3 is constructed by stacking multiple flat core pieces 9 in the axial direction (see Figure 2). If the rotor 1 is an SPM rotor, the rotor core 3 may be a single columnar member instead of a stack of core pieces 9. The axial direction refers to the direction along the axis of the rotor 1. The radial direction refers to the direction along the diameter of the rotor 1, and the circumferential direction refers to the circumferential direction around the axis of the rotor 1. The top and bottom refer to the top and bottom of the rotor 1 when its axial direction is aligned with the vertical direction.

[0030] The multiple core pieces 9 of the rotor core 3 are held in a stacked state by the annular member 5. Therefore, the multiple core pieces 9 are not directly joined to each other by crimping or bonding, but are indirectly joined via the annular member 5. In this connection, the outer circumferences of the multiple core pieces 9 of the rotor core 3 are engaged in a crimp-fit ​​state via the hardened resin 13 on the inner circumference of the annular member 5. It is also possible to directly join and integrate the multiple core pieces 9 by crimping or bonding.

[0031] Each core piece 9 is formed, for example, by punching out an electrical steel sheet or a silicon steel sheet. The thickness of the core piece 9 is 0.5 mm or less, for example, 0.2 mm to 0.35 mm, before attachment to the annular member 5.

[0032] The stacking of these core pieces 9 gives the rotor core 3 an overall columnar, particularly cylindrical, shape. However, the rotor core 3 may also be a single columnar body.

[0033] A shaft hole 11 is provided in the center of the rotor core 3, and a plurality of magnet housing holes 7 are provided around the shaft hole 11.

[0034] In this embodiment, the shaft hole 11 and the magnet housing hole 7 penetrate the rotor core 3 in the axial direction and open at both end faces 3a of the rotor core 3 in the axial direction. Note that the magnet housing hole 7 may also open at only one end face 3a of the rotor core 3.

[0035] Multiple magnet housing holes 7 are arranged at intervals in the circumferential direction of the rotor core 3. Each magnet housing hole 7 is rectangular in plan view. The shape, number, and arrangement of the magnet housing holes 7 can be modified in various ways.

[0036] Each magnet housing hole 7 houses a magnet (not shown). The magnets can be made of permanent magnets (including those before magnetization), such as ferrite sintered magnet pieces or neodymium magnet pieces.

[0037] The annular member 5 is attached to the outer circumference of the rotor core 3 and functions as a reinforcing member. The annular member 5 is attached to the outer circumference of the rotor core 3. In this embodiment, the annular member 5 is a cylindrical body with openings on both sides in the axial direction. The material of the annular member 5 can be set as appropriate, but for example, it can be metal or a resin such as fiber-reinforced plastic.

[0038] The annular member 5 has a larger axial dimension than the rotor core 3, and its axial end 5a protrudes from both sides of the rotor core 3 in the axial direction (see Figures 3 and 4).

[0039] Note that in Figure 1, for convenience, the axial dimensions of the annular member 5 and the rotor core 3 are shown to be the same. However, as in Figure 1, there are cases where the axial dimensions of the annular member 5 and the rotor core 3 are the same. The radial thickness of the annular member 5 is, for example, 0.2 mm to 2 mm.

[0040] The annular member 5 is attached to the rotor core 3 by the curing of the resin 13 injected between them in the radial direction. The resin 13 cures in a state where it presses the annular member 5 against the rotor core 3 in the radial direction. Therefore, the annular member 5 is attached to the rotor core 3 by interference fit with the cured resin 13. Details of the interference fit will be described later.

[0041] [Manufacturing Apparatus for Rotor] FIG. 2 is a perspective view showing a manufacturing apparatus 15 for the rotor 1 of FIG. 1. FIG. 3 is a sectional view taken along line A - A of FIG. 2. FIG. 4 is a perspective sectional view taken along line A - B of FIG. 2. FIG. 5 is a plan view of the manufacturing apparatus 15 for the rotor 1 of FIG. 2 with the upper mold 17 omitted.

[0042] The manufacturing apparatus 15 for the rotor 1 includes an upper mold 17 and a lower mold 19, an upper fitting member 21 and a lower fitting member 23, a driving unit 25, and a resin injector 27, as shown in FIGS. 2 to 5. The resin injector 27 is only conceptually shown by a two - dotted chain line in FIG. 3.

[0043] The upper mold 17 and the lower mold 19 press the rotor 1 with the rotor core 3 disposed inside the annular member 5 from above and below. The interior of the annular member 5 in this embodiment is an internal space partitioned by the inner circumference of the annular member 5. The lower mold 19 of this embodiment is configured in a plate shape, and the rotor 1 is placed thereon via the lower fitting member 23.

[0044] A columnar mandrel 29 projects from the lower mold 19. The mandrel 29 extends along the axial direction of the rotor 1 placed on the lower mold 19 and fits into the axial hole 11 of the rotor 1. The upper end of the mandrel 29 projects upward from the axial hole 11 of the rotor 1.

[0045] The upper mold 17 is supported so as to be vertically movable with respect to the lower mold 19 to enable pressing of the rotor 1. The vertical movement of the upper mold 17 may be performed by an appropriate driving device such as a linear actuator.

[0046] The upper mold 17 of this embodiment is configured in a plate shape. An inlet 31 for the resin 13 is provided on the upper surface 17a of the upper mold 17. The inlet 31 is formed in a concave shape that opens upward at the central portion of the upper surface 17a of the upper mold 17.

[0047] On the lower surface 17b of the upper mold 17, a plurality of first flow paths 33 extending radially outward from the inlet 31 are provided. The first flow path 33 is in the form of a groove that opens downward with respect to the lower surface 17b of the upper mold 17. This opening is closed by the upper fitting member 21, and the first flow path 33 forms a closed cross-section. The first flow path 33 and the inlet 31 are connected to each other by communication holes 35 respectively.

[0048] Incidentally, the first flow path 33 and the inlet 31 may be provided in the lower mold 19. In this case, the first flow path 33 and the inlet 31 of the upper mold 17 can be omitted, but it is not necessary to omit them.

[0049] The upper fitting member 21 and the lower fitting member 23 are respectively fitted in the inner circumference of the upper and lower end portions 5a of the annular member 5 in the radial direction. The end portion 5a of the annular member 5 protrudes axially with respect to the axial end portion 3a of the rotor core 3.

[0050] By such fitting, the space between the upper fitting member 21 and the lower fitting member 23 and the annular member 5 is sealed. This fitting may be performed in the process of the upper fitting member 21 and the lower fitting member 23 expanding in diameter as described later.

[0051] Therefore, the fitting may be either when there is no initial gap between the outer circumferences of the upper fitting member 21 and the lower fitting member 23 and the inner circumference of the end portion 5a of the annular member 5, or when there is an initial gap and this gap disappears due to the expansion of the upper fitting member 21 and the lower fitting member 23.

[0052] The upper fitting member 21 and the lower fitting member 23 of this embodiment are respectively plate-shaped or plug-shaped and are accommodated in the end portion 5a of the annular member 5. The upper surface 21a of the upper fitting member 21 is flush with the upper end portion 5a of the annular member 5, and the lower surface 21b is arranged to abut against the end face 3a of the rotor core 3.

[0053] The upper surface 23a of the lower fitting member 23 abuts against the end face 3a of the rotor core 3, and the lower surface 23b is arranged to be flush with the end face 5b of the lower end portion 5a in the axial direction of the annular member 5.

[0054] The upper surface 21a of the upper fitting member 21 and the lower surface 23a of the lower fitting member 23 are in contact with the lower surface 17b of the upper mold 17 and the upper surface 19a of the lower mold 19, respectively. Note that the lower surface of the lower fitting member 23 does not need to be flush with the axial end face of the annular member 5.

[0055] The upper fitting member 21 and the lower fitting member 23 are pressed together by the pressure from the upper mold 17 and the lower mold 19, respectively, so that their lower surface 21b and upper surface 23a are in close contact with the end face 3a of the rotor core 3. This prevents the resin 13 from being injected between the upper fitting member 21 and the lower fitting member 23 and the rotor core 3.

[0056] The upper fitting member 21 and the lower fitting member 23 are configured to expand radially outward. In this embodiment, the upper mold 17 and the lower mold 19 are each configured in a disc shape and are divided into a plurality of movable parts 37 in the circumferential direction. In this embodiment, there are four movable parts 37, but this number can be set arbitrarily. This division allows each of the movable parts 37 to move radially.

[0057] The upper fitting member 21 and the lower fitting member 23 each have positioning holes 21c and 23c in their central portions. The core metal 29 of the lower mold 19 is inserted axially through the positioning hole 23c of the lower fitting member 23, and the upper end of the core metal 29 is inserted into the positioning hole 21c of the upper fitting member 21. As a result, the upper fitting member 21 and the lower fitting member 23 are positioned radially relative to the rotor 1.

[0058] The upper fitting member 21 has a plurality of second flow channels 39 made of resin 13. Each of the second flow channels 39 consists of a hole that communicates between the first flow channel 33 and the gap 41 of the rotor 1. In this embodiment, the second flow channels 39 extend axially from the radially outer end of the first flow channel 33 and penetrate the upper fitting member 21.

[0059] On the lower surface 21b of the upper fitting member 21, the second flow path 39 extends radially outward and opens to the outer circumference of the upper fitting member 21. As a result, the second flow path 39 reaches the gap 41 of the rotor 1. In this way, by extending radially, the second flow path 39 is ensured to reach the gap 41 even when the movable part 37 moves radially.

[0060] Furthermore, part or all of the first channel 33 may be provided in the upper fitting member 21 together with the second channel 39. Also, if the first channel 33 and the inlet 31 are provided in the lower mold 23, the second channel 39 may be provided in the lower mold 23.

[0061] The drive unit 25 expands the diameter of the upper fitting member 21 and the lower fitting member 23 radially outward. The drive unit 25 is provided both between the upper fitting member 21 and the upper mold 17, and between the lower fitting member 23 and the lower mold 19. However, the drive unit 25 may be provided only between the upper fitting member 21 and the upper mold 17, which is the resin 13 inflow side.

[0062] The drive unit 25 consists of a cam section. Specifically, the drive unit 25 presses the upper fitting member 21 and the lower fitting member 23 radially outward by the pressure from the upper mold 17 and the lower mold 19, thereby expanding their diameters. More precisely, the drive unit 25 is composed of tapered surfaces 25a and 25b that come into contact with each other. The drive unit 25 may have only one of the tapered surfaces 25a and 25b.

[0063] Between the upper fitting member 21 and the upper mold 17, a tapered surface 25a is provided on the inner circumference of the positioning hole 21c of the upper fitting member 21. A tapered surface 25b is provided on the outer circumference of the projection 17c that protrudes downward from the lower surface 17b of the upper mold 17.

[0064] The tapered surface 25a consists of an inclined surface that gradually increases the inner diameter of the positioning hole 21c toward upward. In accordance with this inclination, the tapered surface 25b is inclined that gradually increases the outer diameter of the projection 17c toward upward. The projection 17c is provided with a recess 17d at its tip so as not to interfere with the core metal 29 within the positioning hole 21c of the upper fitting member 21.

[0065] Between the lower fitting member 23 and the lower mold 19, a tapered surface 25a is provided on the inner circumference of the positioning hole 23c of the lower fitting member 23, and a tapered surface 25b is provided on the outer circumference of the base end portion 19c of the core metal 29 of the lower mold 19. The tapered surface 25a consists of an inclined surface that gradually increases the inner diameter of the positioning hole 23c toward downward. In accordance with this inclination, the tapered surface 25b is inclined to gradually increase the outer diameter of the core metal 29 toward downward.

[0066] The resin injector 27 injects resin 13 into the gap 41 of the rotor 1 through the inlet 31, the first channel 33, and the second channel 39. The resin injector 27 can be constructed using a well-known injection unit or the like. Alternatively, the resin injector 27 may connect a tube or the like to the second channel 39 and inject the resin 13 directly into the second channel 39.

[0067] The resin injection machine 27 presses the annular member 5 radially outward relative to the rotor core 3 by injecting the resin 13. In this embodiment, the pressure is such that the gap 41 between the ends 3a expands in accordance with the gap 41 expanded at the ends 3a of the rotor core 3. However, the degree of pressure is arbitrary.

[0068] [Rotor Manufacturing Method] Figures 6(A) and 6(B) are cross-sectional views before and after the rotor core 3 is placed inside the annular member 5. Figure 6(A) shows the state before placement, and Figure 6(B) shows the state after placement. Figure 7 is an enlarged cross-sectional view showing the gap 41 between the rotor core 3 and the annular member 5 in Figure 6(B).

[0069] In the manufacturing method of the rotor 1 of this embodiment, as shown in Figures 6(A) and 6(B), a columnar rotor core 3 is first placed inside the annular member 5.

[0070] Specifically, with the annular member 5 and the rotor core 3 separated as shown in Figure 6(A), the inner circumference of the annular member 5 and the outer circumference of the rotor core 3 are aligned and moved so as to slide relative to each other. As a result, the rotor core 3 is inserted and positioned inside the annular member 5 as shown in Figure 6(B).

[0071] At this time, as shown in Figure 7, the inner diameter of the annular member 5 is larger than the outer diameter of the rotor core 3, meaning there is a radial gap (clearance) 41 between the inner circumference of the annular member 5 and the outer circumference of the rotor core 3. This allows for smooth insertion of the rotor core 3 into the annular member 5 and suppresses damage to the inner circumference of the annular member 5. The gap 41 is set to, for example, 0.1 mm to 0.3 mm. In this state, the rotor 1 is in a temporary assembly state with the annular member 5 attached to the rotor core 3 by clearance fitting.

[0072] Figure 8 is a cross-sectional view showing the rotor 1 in a pre-assembled state placed on the lower mold 19. Figure 9 is a cross-sectional view showing the upper fitting member 21 placed on the pre-assembled rotor 1 on the lower mold 19. Figure 10 is a cross-sectional view showing the rotor 1 in a pre-assembled state placed between the upper mold 17 and the lower mold 19. Figure 11 is a cross-sectional view showing the rotor 1 in the pre-assembled state of Figure 10 under pressure.

[0073] After the rotor core 3 is placed inside the annular member 5, the radial gap 41 between the annular member 5 and the axial end 3a of the rotor core 3 is expanded before the resin 13 is injected. This expansion of the gap 41 may also be performed during the injection of the resin 13.

[0074] In this embodiment, the gap 41 is expanded using the rotor 1 manufacturing apparatus 15. Specifically, as shown in Figure 10, the rotor 1 in a partially assembled state is placed between the lower mold 19 and the upper mold 17 and pressurized.

[0075] When positioning the temporarily assembled rotor 1 between the lower mold 19 and the upper mold 17, the upper mold 17 is raised in advance. Then, as shown in Figure 8, the shaft hole 11 of the temporarily assembled rotor 1 is inserted through the core metal 29 of the lower mold 19, and the temporarily assembled rotor 1 is placed on the lower mold 19 via the lower fitting member 23.

[0076] At this time, the lower fitting member 23 is positioned within the lower end 5a of the annular member 5 of the rotor 1. In this state, the tapered surface 25a of the lower fitting member 23 does not completely contact the tapered surface 25b of the lower mold 19, and the rotor 1 is separated from the lower mold 19 in the axial direction.

[0077] Next, as shown in Figure 9, the upper fitting member 21 is positioned within the upper end 5a of the annular member 5 of the rotor 1. The positioned upper fitting member 21 is flush with the end 5a of the annular member 5. In this state, as shown in Figure 10, the upper mold 17 is lowered so that the lower surface 17b of the upper mold 17 comes into contact with the upper fitting member 21 and the end 5a of the annular member 5.

[0078] As the upper mold 17 descends further, the rotor 1 descends as shown in Figure 11, and the tapered surfaces 25a and 25b of the drive unit 25 are pressed against each other. Due to the action of these tapered surfaces 25a and 25b, the movable part 37 moves outward, and the upper fitting member 21 and the lower fitting member 23 expand in diameter.

[0079] This expansion of the diameter allows the upper fitting member 21 and the lower fitting member 23 to fit radially onto the inner circumference of the end portion 5a of the annular member 5. Alternatively, the upper fitting member 21 and the lower fitting member 23 may be pre-fitted onto the inner circumference of the end portion 5a of the annular member 5.

[0080] Figure 12 is an enlarged cross-sectional view showing the expansion of the gap 41 in the rotor 1 in the temporarily assembled state shown in Figure 11. Figure 13 is an enlarged cross-sectional view showing the injection of resin 13 into the gap 41 in the rotor 1 in the temporarily assembled state shown in Figure 12.

[0081] As shown in Figure 11, the diameters of the upper fitting member 21 and the lower fitting member 23 expand in accordance with the descent of the upper mold 17, and as shown in Figure 12, the ends 5a of the annular member 5 are displaced radially outward. This causes the gap 41 at the end 3b of the rotor core 3 to expand radially. When the upper fitting member 21 and the lower fitting member 23 come into contact with the end face 3a of the rotor core 3 in the axial direction, the expansion of the gap 41 due to the diameter expansion is completed.

[0082] As shown in Figures 2 and 3, resin 13 is injected between the annular member 5 and the rotor core 3 through the thus expanded gap 41, pressing the annular member 5 radially outward relative to the rotor core 3. In this embodiment, the resin 13 is injected from the inlet 31 of the upper mold 17 using a resin injection machine 27.

[0083] In the case of an IPM rotor, as in this embodiment, the injection of resin 13 can be performed at the time of fixing the magnet to the rotor core 3 or before or after that. On the other hand, in the case of an SPM rotor, the injection of resin 13 can be performed at the time of fixing the magnet to the rotor core 3 or after that.

[0084] The resin 13 injected from the inlet 31 travels through the first channel 33 and the second channel 39, as shown in Figure 13, to the gap 41 between the upper end 3b of the rotor core 3 and the annular member 5. When the resin 13 is injected when fixing the magnets of the IPM rotor, the resin 13 will also reach the magnet housing hole 7. In this case, a channel leading to the magnet housing hole 7 should be formed in the upper fitting member 21. When the resin 13 is injected when fixing the magnets of the SPM rotor, the magnets should be positioned around the rotor core 3, and then the resin 13 should be injected as shown in Figure 13. The resin 13 that reaches the gap 41 is prevented from leaking because the upper fitting member 21 is in contact with the rotor core 3 and the annular member 5.

[0085] At this time, since the upper fitting member 21 is in contact with the rotor core 3 and the annular member 5, the sealing performance is improved, and the resin 13 can be reliably injected into the gap 41 between the annular member 5 and the rotor core 3 while suppressing leakage of the resin 13. In addition, since the gap 41 is expanded in the part into which the resin 13 flows, the resin 13 can be reliably injected into the gap 41 between the annular member 5 and the rotor core 3 before it hardens.

[0086] The injected resin 13 presses the annular member 5 radially outward relative to the rotor core 3. This pressure causes the annular member 5 to elastically deform radially outward not only at both ends 5a but as a whole. In this embodiment, the annular member 5 expands radially outward between its ends 5a in accordance with the gap 41 expanded at the end 3b of the rotor 1.

[0087] The resin 13 is cured while the annular member 5 is pressed with the resin 13. Preferably, the pressed state at this time is the same as the state when the resin 13 was injected, but the pressure may be higher or lower than when the resin 13 was injected. In other words, it is sufficient that the annular member 5 is pressed radially outward compared to before the injection of the resin 13.

[0088] Once the resin 13 hardens, the annular member 5 is attached to the rotor core 3. In this state, the hardened resin 13 maintains a position where the annular member 5 is pressed radially outward against the rotor core 3. In other words, the annular member 5 is crimped onto the rotor core 3 via the resin 13.

[0089] Furthermore, since both ends 5a of the annular member 5 are pre-expanded radially, and the portion between the ends 5a is also expanded radially by the resin 13, the rotor 1 is a columnar rotor in which changes in diameter in the axial direction are suppressed.

[0090] As described above, the manufacturing method of the rotor 1 involves placing a columnar rotor core 3 inside an annular member 5 and expanding a radial gap 41 between the annular member 5 and the axial end 3b of the rotor core 3. Resin 13 is injected between the annular member 5 and the rotor core 3 through the expanded gap 41, pressing the annular member 5 radially outward relative to the rotor core 3. Then, the resin 13 is hardened while the annular member 5 is pressed with the resin 13.

[0091] Therefore, in this embodiment, the hardened resin 13 presses the annular member 5 radially outward relative to the rotor core 3, thereby allowing the annular member 5 to be attached to the rotor core 3 by a crimp fit. Consequently, the annular member 5 can be stably attached to the outer circumference of the rotor core 3 regardless of its material.

[0092] Furthermore, the placement of the rotor core 3 inside the annular member 5 can be easily and smoothly carried out while suppressing damage, etc., because there is a radial gap 41 between the rotor core 3 and the annular member 5.

[0093] Furthermore, in this embodiment, by expanding the radial gap 41 between the annular member 5 and the axial end 3b of the rotor core 3, the resin 13 can be injected between the annular member 5 and the rotor core 3 before the resin 13 begins to harden. Therefore, the injected resin 13 can reliably press the annular member 5 against the rotor core 3. As a result, the annular member 5 and the rotor core 3 can be reliably fitted together by the hardened resin 13.

[0094] Furthermore, in this embodiment, the radial gap 41 between the annular member 5 and both axial ends 3b of the rotor core 3 is expanded, so that a columnar rotor 1 can be obtained in which the overall change in outer diameter is suppressed after the resin 13 hardens.

[0095] In this embodiment, with the rotor core 3 positioned inside the annular member 5, the annular member 5 has an axial end 5a that protrudes axially from the end 3b of the rotor core 3. The end 5a of the annular member 5 is then displaced radially outward to expand the gap 41 radially between the annular member 5 and the axial end 3b of the rotor core 3.

[0096] Therefore, the gap 41 between the annular member 5 and the axial end 3b of the rotor core 3 can be easily expanded.

[0097] When expanding the gap 41 radially in this way, the upper fitting member 21 is fitted radially onto the inner circumference of the end portion 5a of the annular member 5, and the upper fitting member 21 is expanded in a way that allows it to be restored to its original size.

[0098] Therefore, the radial gap 41 between the annular member 5 and the axial end 3b of the rotor core 3 can be expanded more easily and reliably.

[0099] In this embodiment, the upper fitting member 21 consists of a plurality of movable parts 37 that can move radially. The drive unit 25 for expanding the diameter of the upper fitting member 21 is provided between the upper fitting member 21 and the upper mold 17, and is a cam part that expands the diameter of the upper fitting member 21 by pressing it radially outward through the pressure of the upper mold 17 and the lower mold 19. Therefore, a dedicated drive unit for expanding the diameter of the upper fitting member 21 is not required.

[0100] The upper fitting member 21 has a second flow path 39 for the resin 13 that leads to the gap 41 between the end 3b of the rotor core 3 and the annular member 5. Therefore, the flow path for the resin 13 can be secured simply by fitting the upper fitting member 21 onto the end 5a of the annular member 5.

[0101] [Modified Example] Figure 14 is a perspective view showing a part of the manufacturing apparatus 15 for the rotor 1 according to a modified example of Embodiment 1, with the upper mold omitted.

[0102] As shown in Figure 14, the modified manufacturing apparatus 15 is equipped with an expansion ring 43 as a fitting member. Note that the expansion ring 43 in Figure 14 is used in place of the upper fitting member 21 in Embodiment 1. As the fitting member on the lower mold side, either the lower fitting member 23 or the expansion ring 43 from Embodiment 1 can be used.

[0103] The expansion ring 43 expands in diameter due to radial expansion. This expansion displaces the end 5a of the annular member 5 radially outward, thereby expanding the gap 41 radially between the annular member 5 and the axial end 3a of the rotor core 3.

[0104] The expansion ring 43 can be expanded not only by pressing with the upper mold 17, but also by heat, hydraulics, or other drive mechanisms. When pressing with the upper mold 17, the tapered surface 25a (see Example 1) of the upper mold 17 is brought into contact with the inner circumference of the expansion ring 43, and the expansion ring 43 is pressed radially outward by the downward movement of the upper mold 17. In this case, the diameter of the tapered surface 25a is made larger than in Example 1. When expanding the expansion ring 43 by heat, the drive unit 25 is composed of a heater that raises the upper mold 17 and the lower mold 19 to the molding temperature.

[0105] The second flow path 39 of the expansion ring 43 is a hole that penetrates the expansion ring 43 axially, similar to the first embodiment. The second flow path 39 extends radially on the lower surface 43a of the expansion ring 43 and opens to the outer circumference of the expansion ring 43. As a result, the second flow path 39 reaches the gap 41 of the rotor 1. The first flow path 33 may be formed by a hole that extends from the inlet 31 of the upper mold 17 to the second flow path 39.

[0106] Even with this modified example, the same effects and advantages as in Example 1 can be achieved.

[0107] Figure 15 is a perspective view showing a part of a rotor manufacturing apparatus according to another modification of Example 1, with the upper mold omitted.

[0108] The modified example in Figure 15 omits the drive unit 25 and includes a tapered surface 43a that gradually increases the outer diameter of the expansion ring 43 toward the top. Therefore, the expansion ring 43 has a shape that expands and widens from bottom to top due to the change in its outer diameter.

[0109] In this modified example, the expansion ring 43 is pushed against the end 5a of the annular member 5 by the pressure applied by the upper mold 17, thereby displacing the end 5a of the annular member 5 radially outward in accordance with the tapered surface 43a.

[0110] Therefore, in this modified example, in addition to the effects of Example 1, the structure of the rotor 1 manufacturing apparatus 15 can be simplified.

[0111] [Rotor Manufacturing Apparatus] Figure 16 is a cross-sectional view showing a rotor manufacturing apparatus according to Embodiment 2 of the present invention. In Embodiment 2, the basic configuration is the same as that of Embodiment 1, and components corresponding to those in Embodiment 1 are indicated by the same reference numerals, and redundant explanations are omitted.

[0112] The rotor 1 manufacturing apparatus 15 includes an upper abutment member 45 and a lower abutment member 47, and an upper inner member 49 and a lower inner member 51, in place of the upper fitting member 21 and lower fitting member 23 of Embodiment 1.

[0113] The upper abutment member 45 and the lower abutment member 47 are abutted in the axial direction against the axial end 5a of the annular member 5 of the rotor 1. In this embodiment, the axial end 5a of the annular member 5 and the axial end 3b of the rotor core 3 are flush with each other.

[0114] The upper abutment member 45 and the lower abutment member 47 are supported by the upper mold 17 and the lower mold 19, respectively. The upper abutment member 45 and the lower abutment member 47 are annular in shape and have tips 45a and 47a that protrude downward relative to the upper mold 17 and upward relative to the lower mold 19, respectively. The tips 45a and 47a of the upper abutment member 45 and the lower abutment member 47 abut against the axial end 5a of the annular member 5 from above and below, respectively.

[0115] In this abutment state, the upper abutment member 45 and the lower abutment member 47 allow displacement of the end 5a of the annular member 5 relative to the end 3b of the rotor core 3 due to elastic deformation. The elasticity of the upper abutment member 45 and the lower abutment member 47 can be set by the thickness and material of the upper abutment member 45 and the lower abutment member 47.

[0116] The displacement of the end 5a of the annular member 5 is performed by the resin injection machine 27. Therefore, the resin injection machine 27 in this embodiment is configured to displace the end 5a of the annular member 5 radially relative to the axial end 3b of the rotor core 3 by injecting resin 13.

[0117] The upper inner member 49 and the lower inner member 51 are positioned radially inward of the upper abutment member 45 and the lower abutment member 47, respectively. The upper inner member 49 and the lower inner member 51 are formed in a disc shape. The upper inner member 49 and the lower inner member 51 are positioned between the upper mold 17 and the lower mold 19 and the rotor core 3, respectively, when the upper abutment member 45 and the lower abutment member 47 are abutting against the annular member 5.

[0118] The lower inner member 51 has a positioning hole 51a in its center. The core metal 29 of the lower mold 19 is inserted through this positioning hole 51a. The upper inner member 49 has a positioning recess 49a in its center. The positioning recess 49a opens downwards, allowing the upper end of the core metal 29 to be inserted. As a result, the upper inner member 49 and the lower inner member 51 are positioned radially.

[0119] In this positioning state, a second flow path 39 of resin 13 is defined between the upper inner member 49 and the upper abutment member 45. A gap 53 corresponding to the second flow path 39 is also defined between the lower inner member 51 and the lower abutment member 47. The second flow path 39 leads to the gap 41 between the end 3b of the rotor core 3 and the end 5a of the annular member 5.

[0120] The second flow path 39 communicates with the inlet 31 via the first flow path 33, similar to the first embodiment. The inlet 31 is formed in a concave shape on the upper surface 17a of the upper mold 17, and the first flow path 33 is a groove that extends radially from the inlet 31 on the lower surface 17b of the upper mold 17 to the outer circumference of the upper mold 17. Therefore, the resin 13 from the resin injection machine 27 is injected from the inlet 31 into the gap 41 via the first flow path 33 and the second flow path 39.

[0121] [Rotor Manufacturing Method] In the manufacturing method of the rotor 1 of this embodiment, the rotor 1 in a temporarily assembled state, with the rotor core 3 placed inside the annular member 5, is placed between the lower mold 19 and the upper mold 17 and pressurized, similar to the first embodiment.

[0122] When positioning the temporarily assembled rotor 1 between the lower mold 19 and the upper mold 17, the upper mold 17 is raised in advance, and the shaft hole 11 of the temporarily assembled rotor 1 is inserted through the mandrel 29 of the lower mold 19 to position the temporarily assembled rotor 1 on the lower mold 19. In this state, the annular member 5 of the temporarily assembled rotor 1 is placed on the lower abutment member 47, and the rotor core 3 is placed on the lower inner member 51.

[0123] Next, the upper mold 17 is lowered. This lowering causes the upper inner member 49 to come into contact with the upper end 3b of the rotor core 3, and the upper abutment member 45 to abut against the upper end 5a of the annular member 5.

[0124] Next, resin 13 is injected into the gap 41 between the annular member 5 and the rotor core 3 to press the annular member 5 radially outward relative to the rotor core 3. In this embodiment, the injection of resin 13 allows the end portion 5a of the annular member 5 to be displaced radially relative to the end portion 3b of the rotor core 3.

[0125] The resin 13 is injected from the inlet 31 of the upper mold 17 using a resin injection machine 27, as in Example 1. The injected resin 13 travels from the inlet 31 through the first channel 33 and the second channel 39 to the gap 41 between the upper end 3b of the rotor core 3 and the upper end 5a of the annular member 5.

[0126] The resin 13 that reaches the gap 41 presses the annular member 5 radially outward relative to the rotor core 3 due to its pressure. This pressing causes the entire axial area of ​​both ends 5a and the portion between both ends 5a of the annular member 5 to be displaced radially outward.

[0127] In this case, the upper abutment member 45 and the lower abutment member 47 at both ends 5a of the annular member 5 are elastically deformed, allowing for displacement. Therefore, radial outward displacement can be smoothly performed throughout the entire annular member 5.

[0128] Due to the displacement of the end portion 5a of the annular member 5, the gap 41 is expanded, including the portion into which the resin 13 flows. Therefore, the resin 13 can be reliably injected into the gap 41 between the annular member 5 and the rotor core 3 before it hardens.

[0129] Then, when the resin 13 is hardened while the annular member 5 is pressed, the annular member 5 is attached to the rotor core 3. In this state, the annular member 5 is tightly fitted onto the rotor core 3 via the hardened resin 13.

[0130] Therefore, in Example 2, the same effects and advantages as in Example 1 can be achieved, and the structure of the manufacturing apparatus 15 can be simplified.

[0131] 1 Rotor 3 Rotor core 3b End 5 Annular member 5a End 9 Core piece 13 Resin 15 Manufacturing apparatus 17 Upper mold 19 Lower mold 21 Upper fitting member 23 Lower fitting member 25 Drive unit 25a Tapered surface 25b Tapered surface 27 Resin injection machine 37 Movable part 39 Second flow path (flow path) 41 Gap 43 Expansion ring (fitting member) 45 Upper abutment member 47 Lower abutment member 49 Upper inner member 51 Lower inner member

Claims

1. A method for manufacturing a rotor, comprising: arranging a columnar rotor core inside an annular member; expanding a radial gap between the annular member and the axial end of the rotor core; injecting resin between the annular member and the rotor core through the expanded gap to press the annular member radially outward relative to the rotor core; and curing the resin while the annular member is pressed by the resin.

2. A method for manufacturing a rotor according to claim 1, wherein the expansion of the gap is performed between the annular member and the axial ends of the rotor core, and the injection of the resin is performed through the expanded gap between the annular member and one of the ends of the rotor core.

3. A method for manufacturing a rotor according to claim 1, wherein the annular member has an axial end that protrudes in the axial direction from the end of the rotor core when the rotor core is placed inside it, and the gap is expanded by displacing the end of the annular member radially outward.

4. A method for manufacturing a rotor according to claim 3, comprising fitting a fitting member to the inner circumference of the end of the annular member in the radial direction, and expanding the gap by resizable diameter of the fitting member.

5. A method for manufacturing a rotor according to claim 4, wherein the fitting member comprises a plurality of movable parts that can move in the radial direction, and the fitting member is expanded in diameter by the radial movement of the movable parts.

6. A method for manufacturing a rotor according to claim 4, wherein the fitting member is made of a ring-shaped member and expands in diameter by radial expansion.

7. A method for manufacturing a rotor according to claim 1, wherein, when expanding the gap, the axial end of the annular member is displaced radially outward relative to the end of the rotor core by injecting the resin into the gap.

8. A method for manufacturing a rotor according to claim 7, wherein abutment member is abutted against the end of the annular member in the axial direction, and the abutment member elastically deforms when the resin is injected into the gap, thereby allowing the displacement of the end of the annular member relative to the end of the rotor core.

9. A rotor manufacturing apparatus comprising: a rotor in which a columnar rotor core is placed inside an annular member and the axial end of the annular member protrudes in the axial direction relative to the axial end of the rotor core, and a fitting member that fits radially to the inner circumference of the end of the annular member; a drive unit that expands the diameter of the fitting member radially outward; and a resin injection machine that injects resin from the radial gap between the end of the rotor core, which has been expanded radially by the expansion of the fitting member, and the annular member, thereby pressing the annular member radially outward relative to the rotor core.

10. A rotor manufacturing apparatus according to claim 9, wherein the fitting member has a flow path for the resin leading to the gap between the end of the rotor core and the annular member.

11. A rotor manufacturing apparatus according to claim 9, comprising an upper die and a lower die for pressurizing the rotor from above and below, wherein the drive unit is a cam portion provided between the fitting member and the upper die or the lower die, and which presses the fitting member radially outward by the pressurizing of the upper die and the lower die to expand its diameter.

12. A rotor manufacturing apparatus according to claim 11, wherein the fitting member comprises a plurality of movable parts that are movable in the radial direction, and the drive unit moves the movable parts outward in the radial direction.

13. A rotor manufacturing apparatus according to claim 10, wherein the fitting member is made of a ring-shaped member, and the drive unit expands the fitting member in the radial direction.

14. A rotor manufacturing apparatus comprising: a rotor having a columnar rotor core arranged inside an annular member, an abutment member positioned and abutting the axial end of the annular member in the axial direction; and a resin injection machine that injects resin into the radial gap between the annular member and the rotor core, thereby pressing the annular member radially outward relative to the rotor core, wherein the resin injection machine displaces the end of the annular member radially relative to the axial end of the rotor core by injecting the resin, and the abutment member allows the displacement of the end of the annular member relative to the end of the rotor core by elastic deformation.

15. A rotor manufacturing apparatus according to claim 14, comprising: an inner member disposed radially inside the abutment member; and a flow path for the resin partitioned between the abutment member and the inner member, leading to the gap between the end of the rotor core and the end of the annular member.

Images