Stator manufacturing method

Abstract

In the manufacturing process of a stator in which the coil ends are covered with resin and the wire connection points are covered with insulating resin, the stator is manufactured efficiently while suppressing resin dripping from the coil ends. [Solution] A method for manufacturing a stator, comprising the step of preparing a workpiece. The workpiece comprises a coil in which a plurality of wires are connected and a stator core having a cylindrical shape. The coil is wound around the stator core. The workpiece has coil ends from which the coil protrudes from the ends of the stator core. The manufacturing method comprises the steps of applying a first resin to the coil ends, pre-curing the first resin applied to the coil ends, applying an insulating second resin to the connection portions between the wires, and heating the workpiece to cure the first resin and the second resin.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a method for manufacturing a stator.

[0002] In the method for manufacturing a stator disclosed in Patent Document 1, resin (specifically, varnish) is applied to the coil ends, and then the resin is cured by heating. By coating the coil ends with resin in this way, the noise and vibration performance of the stator can be improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method for manufacturing a stator of Patent Document 1, after applying resin to the coil ends, the resin is cured. On the other hand, in a stator, an insulating resin may be provided to cover the connection portions between the wire materials constituting the coil. In this case, if resin is applied to the coil ends, then insulating resin is applied to the connection portions, and then the resin on the coil ends and the insulating resin are cured together by heating, the stator can be manufactured efficiently. However, in this case, since the time from the resin application step to the curing step for the coil ends becomes long, the resin may drip from the coil ends. When the resin drips from the coil ends, a step of removing the dripped resin is required, and the production efficiency of the stator decreases. In this specification, a technique for efficiently manufacturing a stator while suppressing the dripping of resin from the coil ends in the manufacturing process of a stator in which the coil ends are covered with resin and the connection portions of the wire materials are covered with insulating resin is proposed.

Means for Solving the Problems

[0005] A method for manufacturing a stator disclosed herein includes a step of preparing a workpiece. Here, a workpiece is prepared which has a coil in which a plurality of wires are connected and a stator core having a cylindrical shape, the coil being wound around the stator core and having coil ends from which the coil protrudes from the ends of the stator core. This manufacturing method includes a step of applying a first resin to the coil ends, a step of pre-curing the first resin applied to the coil ends, a step of applying an insulating second resin to the connection portions between the wires, and a step of heating the workpiece to cure the first resin and the second resin.

[0006] In this manufacturing method, a first resin is applied to the coil end, and the applied first resin is partially cured. Therefore, dripping of the first resin from the coil end afterward can be suppressed. After partially curing the first resin, an insulating second resin is applied to the connection points between the wires. Then, the workpiece is heated to cure the first and second resins. Since the first and second resins can be cured together, the stator can be manufactured efficiently. As described above, this manufacturing method allows for the efficient manufacture of stators while suppressing dripping of the first resin from the coil end. [Brief explanation of the drawing]

[0007] [Figure 1] Perspective view of stator 100. [Figure 2] Enlarged perspective view of the upper part of stator 100. [Figure 3] A plan view of the inner surface of stator 100 when viewed from above. [Figure 4] Plan view of segment coil 60. [Figure 5] A flowchart showing the manufacturing method of stator 100. [Figure 6] Diagram illustrating the varnish coating process for coil end 30b. [Figure 7] Diagram illustrating the irradiation position of ultraviolet (UV) light. [Figure 8] Diagram illustrating the varnish coating process for coil end 30a. [Modes for carrying out the invention]

[0008] In one example of a manufacturing method disclosed herein, the first resin may be irradiated with ultraviolet light in the step of pre-curing the first resin.

[0009] This configuration allows the first resin to be easily partially cured.

[0010] In one example of a manufacturing method disclosed herein, in the step of applying the first resin to the coil end, the workpiece may be positioned such that the coil end is located above the stator core when the first resin is applied to the coil end.

[0011] In one example of a manufacturing method disclosed herein, in the step of pre-curing the first resin, ultraviolet light may be irradiated onto the first resin applied to the coil end while the step of applying the first resin to the coil end is being performed.

[0012] With this configuration, the first resin can be partially cured immediately after being applied to the coil end, thus more effectively suppressing the dripping of the first resin.

[0013] In one example of a manufacturing method disclosed herein, in the step of pre-curing the first resin, ultraviolet light may be irradiated onto the portion of the coil end below the center in the vertical direction.

[0014] This configuration makes it possible to more effectively suppress the dripping of the first resin onto the stator core.

[0015] The stator 100 shown in Figure 1 has a stator core 20 and a coil 30. The stator core 20 has a substantially cylindrical shape with a central axis CL. The coil 30 is wound around the stator core 20.

[0016] The stator core 20 is made of a magnetic material. The stator core 20 has end faces 20a and 20b on both sides in the axial direction. As shown in FIG. 2, the stator core 20 has a back yoke 26 and a plurality of teeth 24. The back yoke 26 has a cylindrical shape centered on the central axis CL. Each tooth 24 has a convex shape protruding from the inner peripheral surface of the back yoke 26 toward the central axis CL. The plurality of teeth 24 are arranged at intervals in the circumferential direction of the stator core 20. As shown in FIG. 3, each tooth 24 extends from the end face 20a to the end face 20b along the axial direction. A slot 22 is provided between each tooth 24.

[0017] The coil 30 is formed by connecting a plurality of segment coils 60 shown in FIG. 4. The segment coil 60 is a substantially U-shaped wire. The segment coil 60 has a bent portion 60b, two straight portions 60c, and two end portions 60a. The bent portion 60b is a portion where the conductor is bent into a U shape. Each straight portion 60c is a portion where the conductor extends linearly from the bent portion 60b. The two straight portions 60c extend in parallel. At the ends of each straight portion 60c on the side opposite to the bent portion 60b, the conductor is bent obliquely outward, and an end portion 60a is provided at the tip of the obliquely extending portion. The conductor constituting the segment coil 60 is covered with an insulating coating. However, at each end portion 60a, no insulating coating is provided and the conductor is exposed.

[0018] The plurality of segment coils 60 are attached to the stator core 20 as shown in FIG. 3. That is, each straight portion 60c of each segment coil 60 is disposed in the slot 22. As shown in FIG. 2, a plurality of straight portions 60c are laminated in the radial direction of the stator core 20 in each slot 22. As shown in FIG. 3, each end portion 60a of each segment coil 60 is disposed so as to protrude from the end face 20a of the stator core 20. The bent portion 60b of each segment coil 60 is disposed so as to protrude from the end face 20b of the stator core 20.

[0019] As shown in Figure 2, the end 60a of a segment coil 60 is positioned adjacent to the end 60a of another segment coil 60. Numerous pairs 62 of end 60a are formed on the end face 20a of the stator core 20. The two end 60a constituting a pair 62 are welded together. Hereafter, a pair 62 (i.e., two ends 60a welded to each other) will be referred to as a welded portion 62. The coil 30 is formed by welding the segment coils 60 together in this manner. As shown in Figure 3, each welded portion 62 is covered with a thick insulating resin 64. The insulating resin 64 is made of, for example, an insulating powder coating. Note that the insulating resin 64 is not shown in figures other than Figure 3.

[0020] As shown in Figures 1-3, a coil end 30a is formed by a portion protruding from the end face 20a of each segment coil 60. The coil end 30a includes a plurality of welded portions 62. Also, as shown in Figure 3, a coil end 30b is formed by a portion protruding from the end face 20b of each segment coil 60. The coil end 30b includes a plurality of bent portions 60b. Except for the surface of the insulating resin 64, the coil ends 30a and 30b are coated with a varnish (not shown). Because the coil ends 30a and 30b are coated with varnish, the segment coils 60 are constrained by the varnish, making it difficult for each segment coil 60 to vibrate. This improves the NV performance of the stator core 20.

[0021] Next, a method for manufacturing the stator 100 will be described. FIG. 5 shows the manufacturing process of the stator 100. In step S2, each segment coil 60 is assembled to the stator core 20. Here, as shown in FIGS. 1 to 3, each segment coil 60 is assembled to the stator core 20 such that the straight portion 60c is accommodated in the slot 22. In step S4, the coil 30 is formed by welding the ends 60a of each segment coil 60 to form the welded portion 62. As a result, as shown in FIG. 6, a workpiece 90 having a structure in which the coil 30 is wound around the stator core 20 is obtained. At this stage, the coil end 30a protrudes from the end face 20a of the stator core 20, and the coil end 30b protrudes from the end face 20b of the stator core 20.

[0022] Next, in step S6, varnish coating is performed on the coil ends 30a and 30b. In step S6, varnish coating is first performed on the coil end 30b, and then varnish coating is performed on the coil end 30a.

[0023] In the varnish coating of the coil end 30b, as shown in Figure 6, the workpiece 90 is positioned with the coil end 30b facing upwards, and varnish 92 is discharged from the nozzle 94 toward the coil end 30b while the workpiece 90 is rotated around the central axis CL. This coats the entire surface of the coil end 30b with varnish 92. The varnish 92 is made of an ultraviolet-curable resin. Because the viscosity of the varnish 92 is low, the entire surface of each segment coil 60 on the coil end 30b is coated with varnish 92. In addition, while applying varnish 92 to the coil end 30b, ultraviolet UV light is irradiated onto the coil end 30b using an ultraviolet light 96. This pre-cures the varnish 92 applied to the coil end 30b. Because the fluidity of the varnish 92 is lost due to pre-curing, dripping of the varnish 92 from the coil end 30b to the stator core 20 and coil end 30a is suppressed. In this case, as shown in Figure 7, ultraviolet UV radiation can be irradiated such that the center of the ultraviolet UV irradiation range is located in a region R below half the height H of the coil end 30b (i.e., the region below the center in the vertical direction of the coil end 30b). By irradiating ultraviolet UV radiation centered on region R in this way, the dripping of varnish 92 onto the stator core 20 and coil end 30a can be suppressed more effectively.

[0024] After applying varnish coating to the coil end 30b, varnish coating is applied to the coil end 30a. Here, as shown in Figure 8, the workpiece 90 is positioned with the coil end 30a facing upwards, and varnish 92 is discharged from the nozzle 94 toward the coil end 30a while the workpiece 90 is rotated around the central axis CL. This coats the entire coil end 30a with varnish 92. In addition, while applying varnish 92 to the coil end 30a, the coil end 30a is irradiated with ultraviolet UV light from the ultraviolet light 96 to partially cure the varnish 92. This prevents the varnish 92 from dripping onto the stator core 20 and the coil end 30b. Here, if ultraviolet UV light is irradiated mainly in the area below the center in the vertical direction of the coil end 30a, the dripping of varnish 92 onto the stator core 20 and the coil end 30b can be effectively suppressed. Furthermore, in the case of varnish coating of the coil end 30a, each welded portion 62 may or may not be coated with varnish 92.

[0025] Next, in step S8, the workpiece 90 is preheated, and in step S10, an insulating resin 64 is formed to cover each welded part 62. For example, each welded part 62 can be covered with the insulating resin 64 by dipping it into the insulating resin 64 stored in the container.

[0026] Next, in step S12, the entire workpiece 90 is heated in a heating furnace to cure the varnish 92 and insulating resin 64. Then, in step S14, the workpiece 90 is cooled to room temperature. This completes the stator 100.

[0027] According to the above manufacturing method, since the varnish 92 is partially cured after application, it is possible to prevent the uncured varnish 92 from dripping onto the stator core 20 or the area below it. Therefore, the step of removing the dripped varnish 92 becomes unnecessary. In addition, the varnish 92 and the insulating resin 64 can be cured simultaneously in the heat curing step. Thus, the stator core 20 can be manufactured efficiently using this manufacturing method.

[0028] In the above-described embodiment, the varnish 92 was pre-cured by irradiation with ultraviolet light, but the varnish 92 may be pre-cured by other methods. For example, a thermosetting resin may be used as the varnish 92, and the varnish 92 may be pre-cured by heating.

[0029] Furthermore, in the embodiment described above, the varnish application step and the pre-curing step of the varnish 92 were performed simultaneously, but the pre-curing step of the varnish 92 may be performed separately from the varnish application step. That is, the pre-curing step of the varnish 92 may be performed after the varnish application step and before the insulating resin application step 64. This configuration also suppresses the sagging of the varnish 92. For example, by performing the pre-curing step of the varnish 92 at an appropriate timing, the varnish 92 can be pre-cured before sagging occurs.

[0030] Furthermore, in the above-described embodiment, both coil ends 30a and 30b were coated with varnish, but only one of the coil ends 30a or 30b may be coated with varnish.

[0031] The varnish 92 in the embodiment is an example of a first resin. The insulating resin 64 in the embodiment is an example of a second resin.

[0032] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. [Explanation of symbols]

[0033] 20: Stator core, 30a: Coil end, 30b: Coil end, 62: Welded part, 64: Insulating resin, 92: Varnish, 96: UV light

Claims

1. A method for manufacturing a stator, The process of preparing a workpiece having a coil in which multiple wires are connected and a stator core having a cylindrical shape, wherein the coil is wound around the stator core and the coil has a coil end protruding from the end of the stator core, The steps include applying the first resin to the coil end, A step of pre-curing the first resin applied to the coil end, The process involves applying an insulating second resin to the connection points between the aforementioned wires, A step of heating the workpiece to cure the first resin and the second resin, A manufacturing method having

2. The manufacturing method according to claim 1, wherein in the step of pre-curing the first resin, the first resin is irradiated with ultraviolet light.

3. The manufacturing method according to claim 1, wherein in the step of applying the first resin to the coil end, the workpiece is positioned such that the coil end is located above the stator core, and the first resin is applied to the coil end.

4. The manufacturing method according to claim 3, wherein, in the step of pre-curing the first resin, the first resin applied to the coil end is irradiated with ultraviolet light while the step of applying the first resin to the coil end is being performed.

5. The manufacturing method according to claim 4, wherein in the step of pre-curing the first resin, ultraviolet light is irradiated onto the portion of the coil end below the center in the vertical direction.

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