Motor coil manufacturing method

Abstract

To provide a coil having suitable insulation even at high temperatures.SOLUTION: A motor coil manufacturing method includes a preparation step (S102) of preparing an annular body, which is a metal block having a ring shape with a hole in the center, a cutting step (S104) of cutting the annular body in the thickness direction at predetermined intervals such that the cut surfaces are perpendicular to the thickness direction of the annular body to form a spiral body in which flat plate portions are connected in a spiral shape, and an insertion step (S108) of inserting an insulating sheet member into the gaps between the flat plate portions of the spiral body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a coil for a motor. [Background technology]

[0002] Patent Document 1 below discloses a motor having a coil wound in a spiral shape, with an insulating coating formed on the surface of the coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-149930 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, as motors have become faster in rotation, heat generation has increased, and so there is a demand for increasing the temperature of the coil to improve the cooling efficiency of the coil using a refrigerant.However, because the insulating coating in Patent Document 1 is formed after the linear member is wound spirally, the insulating coating cannot be formed properly on the coil, and there is a risk that the insulating coating will deteriorate when the coil becomes hot.

[0005] The present invention has been made in consideration of these points, and has as its object to provide a coil that has appropriate insulation even at high temperatures. [Means for solving the problem]

[0006] In one aspect of the present invention, there is provided a method for manufacturing a motor coil, comprising: a preparation step of preparing an annular body, which is a metal block having an annular shape with a hole in the center; a cutting step of cutting the annular body at predetermined intervals in the thickness direction of the annular body so that the cut surfaces are perpendicular to the thickness direction of the annular body, to form a spiral body in which flat portions are connected in a spiral shape; and an insertion step of inserting an insulating sheet member into the gaps between the flat portions of the spiral body.

[0007] In the inserting step, the sheet member may be inserted into the gap so as to surround the through-hole in the central portion.

[0008] In the inserting step, the sheet member may be inserted so that the sheet member is positioned outward from the longitudinal end of the spiral body.

[0009] In the inserting step, the sheet member may be inserted into the gap portion in which the distance between the flat plate portions is smaller than twice the thickness of the sheet member.

[0010] The method may further include a fixing step of fixing the sheet member inserted into the gap to the spiral body.

[0011] The method may further include a coating step of forming an insulating coating on the surface of the spiral, and in the insertion step, the sheet member may be inserted into the gap portion of the spiral having the insulating coating formed on its surface.

[0012] The method may further include a coating step of forming an insulating coating on the surface of the annular body, and in the cutting step, the annular body with the insulating coating formed on the surface may be cut at the predetermined intervals in the thickness direction. [Effects of the Invention]

[0013] The present invention has the effect of realizing a coil that has appropriate insulation even at high temperatures. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a stator 1 to which a coil 10 is attached. [Figure 2] 3 is a flowchart showing the flow of manufacturing the coil 10. [Figure 3] FIG. 1 is a schematic diagram showing an annular body 100. [Figure 4] FIG. 2 is a schematic diagram showing a spiral body 200. [Figure 5] FIG. 2 is a schematic diagram showing a spiral body 200 into which a sheet member 250 is inserted. [Figure 6] FIG. 6 is an enlarged schematic view of a portion A of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Coil Overview> The coil according to this embodiment is a motor coil that is attached to a motor mounted on a vehicle such as a truck. The motor includes a stator and a rotor, and the coil is attached to the stator. Specifically, the coil is provided on the inner peripheral surface of the stator and surrounds the rotor.

[0016] FIG. 1 is a schematic diagram showing a stator 1 to which a coil 10 is attached. As shown in FIG. 1, a plurality of coils 10 are provided on the inner peripheral surface of the stator 1. The plurality of coils 10 are provided at predetermined intervals along the circumferential direction. The coils 10 are attached so as to surround teeth protruding from the inner peripheral surface of the stator 1. Specifically, a through-hole is provided in the center of the coil 10, and the through-hole is fitted into the tooth.

[0017] The multiple coils 10 are arranged so as to surround the rotor 20 shown by the dashed line in Fig. 1. A refrigerant (specifically, cooling oil or cooling water) is filled between the rotor 20 and the coils 10. When the rotor 20 rotates, the refrigerant comes into contact with the coils 10 and cools them. An insulating coating is formed on the coils 10 to ensure insulation from the rotor 20.

[0018] However, as the rotational speed of the motor increases, heat generation increases, and there is a demand to increase the temperature of the coil 10 in order to improve the cooling efficiency of the refrigerant for the coil 10. This is because when the temperature of the coil 10 is high, the temperature difference with the refrigerant increases, and therefore the cooling efficiency of the coil 10 by the refrigerant increases.

[0019] Unlike the present embodiment, in the case of coils in which a linear material is wound around the teeth, a resin-based insulating coating is usually formed, but resin-based insulating coatings deteriorate more rapidly as the temperature increases, so the coil temperature cannot be raised. Forming an insulating coating on the coil using an inorganic material that can withstand high temperatures could be considered, but in the case of coils in which a linear material is wound around the teeth, bending the coil wire could cause cracks or peeling, which could impair the insulation.

[0020] In contrast, when manufacturing the coil 10 according to this embodiment, as will be described in detail later, a metal block is cut to form a spiral (coil) with flat plate portions connected in a spiral shape, and an insulating sheet member is inserted into the gaps between the flat plate portions of the spiral. This ensures proper insulation between the flat plate portions, making it easier to form an insulating coating on the coil 10 that has proper insulation properties even at high temperatures.

[0021] <Coil manufacturing method> A method for manufacturing the coil 10 according to this embodiment will be described with reference to FIG. Fig. 2 is a flowchart showing the flow of manufacturing the coil 10. As shown in Fig. 2, the manufacturing of the coil 10 is performed in the order of a preparation step, a cutting step, a coating step, an insertion step, and a fixing step. Each step will be described below.

[0022] (preparation process) First, as a preparation step, an operator prepares an annular body, which is a metal block having an annular shape with a hole in the center (step S102). For example, the operator prepares an annular body 100 shown in FIG. 3 by cutting out the center of a rectangular parallelepiped metal block.

[0023] FIG. 3 is a schematic diagram showing an annular body 100. Here, the annular body 100 is a block made of copper or aluminum, but is not limited to this and may be made of other metals. The outer shape of the annular body 100 is the same size as the completed coil 10. A rectangular through-hole is formed in a central portion 102 of the annular body 100. The central portion 102 is cut out to a size that allows the teeth of the stator 1 of the motor to be inserted. In this way, the coil 10 of this embodiment is formed from a metal block rather than by winding a wire material.

[0024] (cutting process) Next, in the cutting step, the worker cuts the annular body 100 at predetermined intervals in the thickness direction so that the cut surfaces are perpendicular to the thickness direction of the annular body (step S104). For example, the worker uses a wire cutter or a water cutter to cut the annular body 100 at predetermined intervals in the thickness direction. Specifically, the worker cuts the annular body 100 in a spiral shape parallel to the top surface of the annular body 100. This forms a spiral body 200 in which flat plate portions are connected in a spiral shape, as shown in FIG. 4. The flat plate portions do not contact each other in the thickness direction.

[0025] FIG. 4 is a schematic diagram showing a spiral 200. As shown in FIG. 4, the spiral 200 has a shape in which flat plate portions are stacked in the thickness direction. Here, flat plate portions 212, 213, 214, 215, and 216 are stacked from top to bottom. Therefore, the number of turns of the spiral 200 is five. However, the number of turns of the spiral 200 is not limited to this and may be six or more. Furthermore, gaps 220 are formed between the flat plate portions 212 and 213, between the flat plate portions 213 and 214, between the flat plate portions 214 and 215, and between the flat plate portions 215 and 216 due to cutting.

[0026] Because the coil 10 is attached to the stator of a high-speed motor, it is desirable to have a small number of turns in the coil 10. When manufacturing a coil 10 with a small number of turns, forming the spiral 200 from a block increases the practicality of forming the coil 10.

[0027] (Coating process) Next, in a coating process, the worker forms an insulating coating on the surface of the spiral 200 (step S106). As an example, the worker forms an inorganic insulating coating on the surface of the spiral 200 by thermal spraying. Specifically, the worker sprays molten ceramic onto the surface of the spiral 200 to form the insulating coating. By forming an inorganic insulating coating, it is possible to prevent the insulating properties of the insulating coating from being impaired, compared to a resin-based insulating coating, even if the temperature of the coil 10 becomes high.

[0028] An operator forms an insulating coating on the upper surface 202, lower surface 204, outer surface 206, and inner surface 208 of the spiral 200 by thermal spraying. However, when forming an insulating coating on the spiral 200 by thermal spraying, it is difficult to spray ceramics or the like into the gaps 220 of the spiral 200. For this reason, in this embodiment, an insulating coating is formed on the upper surface 202, lower surface 204, outer surface 206, and inner surface 208 of the spiral 200 that are exposed to the outside.

[0029] The thickness of the flat plate portions 212-216 is large due to the small number of turns of the spiral 200. When an inorganic insulating coating is formed on such flat plate portions 212-216, problems such as cracking and peeling that occur in coils made of linear materials are less likely to occur, and loss of insulation can be suppressed.

[0030] (Insertion process) Next, as an insertion step, the worker inserts insulating sheet member 250 into gap 220 between flat plate portions 212 to 216 of spiral body 200 (step S108). That is, the worker inserts sheet member 250 into gap 220 of spiral body 200 having an insulating coating formed on its surface.

[0031] 5 is a schematic diagram showing the spiral 200 with the sheet member 250 inserted therein. The sheet member 250 is made of an inorganic insulating material. For example, the sheet member 250 is a sheet of aluminum coated with an insulating film of aluminum nitride. However, the sheet member 250 is not limited to this, and may be, for example, an aluminum nitride ceramic board.

[0032] FIG. 6 is a schematic diagram enlarging a portion A in FIG. 5. As shown in FIG. 6, a sheet member 250 is inserted into each gap 220 between the flat plate portions 212 to 216 of the spiral body 200. The thickness of the sheet member 250 is smaller than the distance between the flat plate portions 212 to 216 (in other words, the vertical width of the gap 220). Here, the vertical width of the gap 220 is larger than the thickness of the sheet member 250 but is not more than twice the thickness of the sheet member 250. As an example, the thickness of the sheet member 250 is 50 μm, and the vertical width of the gap 220 is 100 μm. Therefore, the operator inserts the sheet member 250 into the gap 220 whose vertical width is smaller than twice the thickness of the sheet member 250.

[0033] The worker inserts the sheet member 250 so as to fill each gap 220 between the flat plate portions 212 to 216. That is, the worker inserts the sheet member 250 into the gap 220 so as to surround the through-hole 203 (FIG. 5) in the center of the spiral body 200. The worker divides the sheet member 250 into multiple pieces and inserts them into the gaps 220. This allows the sheet member 250 to be inserted into all of the gaps 220 in the spiral body 200.

[0034] The worker inserts the sheet member 250 so that the sheet member 250 is positioned outward from the longitudinal ends of the spiral body 200. Specifically, the worker inserts the sheet member 250 so that the ends of the sheet member 250 inserted into the gap 220 between the flat plate portions 212 and 213 of the spiral body 200 protrude beyond the ends of the flat plate portions 212 and 213.

[0035] When the end of the sheet member 250 protrudes beyond the end of the spiral body 200, heat dissipation from the protruding end can be promoted. In particular, when the rotor 2 (FIG. 1) rotates with the coil 10 attached to the stator 1, the refrigerant is more likely to come into contact with the end of the sheet member 250. This promotes heat dissipation from the end of the sheet member 250 that comes into contact with the refrigerant.

[0036] (Fixed process) Next, as a fixing step, the worker fixes the sheet member 250 inserted into the gap 220 to the spiral 200 (step S110). The worker fixes the sheet member 250 to the gap 220 of the spiral 200, for example, with an adhesive. The worker fixes the sheet member 250 to the gap 220 at predetermined intervals in the longitudinal direction of the sheet member 250.

[0037] Fixing the sheet member 250 to the spiral 200 can prevent the sheet member 250 from shifting relative to the gap 220. As a result, it is possible to prevent poor insulation caused by the sheet member 250 being shifted relative to the gap 220.

[0038] <Modification> In the above description, the cutting step is followed by the coating step of forming an insulating coating on the surfaces (upper, lower, outer and inner surfaces) of the spiral 200, but this is not limiting. For example, the cutting step may be performed after the coating step.

[0039] Specifically, in a coating process, a worker forms an insulating coating on the surface of the uncut annular body 100. The worker sprays molten ceramic onto the upper, lower, outer, and inner surfaces of the annular body 100 to form the insulating coating. Next, in a cutting process, the worker cuts the annular body 100 with the insulating coating formed on its surface at predetermined intervals in the thickness direction. The worker cuts the spiral body 200 parallel to the upper surface with a wire cutter. As a result, the spiral body 200 shown in FIG. 4 is formed in the modified example as well.

[0040] <Effects of this embodiment> In the manufacturing method of the coil 10 described above, a metal block is cut to form the spiral 200 in which the flat plate portions 212 to 216 are connected in a spiral shape, and an insulating sheet member 250 is inserted into the gap portion 220 of the spiral 200. This makes it easier to form an inorganic insulating coating in the gaps 220, where it is difficult to form an insulating coating by thermal spraying. As a result, an insulating coating that has appropriate insulating properties even at high temperatures can be formed on the coil 10.

[0041] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0042] 10 coils 100 cyclic bodies 102 Central part 200 spiral 203 Through hole 212~216 Flat plate part 220 Gap 250 Sheet material

Claims

1. a preparation step of preparing an annular body, which is an annular metal block with a hole in the center; a cutting step of cutting the annular body at predetermined intervals in a thickness direction of the annular body so that cut surfaces are perpendicular to the thickness direction of the annular body, thereby forming a spiral body in which flat plate portions are connected in a spiral shape; an insertion step of inserting an insulating sheet member into a gap between the flat plate portions of the spiral; A method for manufacturing a motor coil having the above structure.

2. In the inserting step, the sheet member is inserted into the gap so as to surround the through-hole in the central portion. A method for manufacturing a coil of the motor according to claim 1.

3. In the inserting step, the sheet member is inserted so that the sheet member is positioned outward from the longitudinal end of the spiral body. A method for manufacturing a coil of the motor according to claim 1.

4. In the inserting step, the sheet member is inserted into the gap portion where the distance between the flat plate portions is smaller than twice the thickness of the sheet member. A method for manufacturing a coil of the motor according to claim 1.

5. The method further includes a fixing step of fixing the sheet member inserted into the gap to the spiral body. A method for manufacturing a coil of the motor according to claim 1.

6. The method further includes a coating step of forming an insulating coating on the surface of the spiral body, In the inserting step, the sheet member is inserted into the gap of the spiral body having the insulating coating formed on the surface thereof. A method for manufacturing a coil of the motor according to claim 1.

7. The method further includes a coating step of forming an insulating coating on the surface of the annular body, In the cutting step, the annular body having the insulating coating formed on the surface thereof is cut at the predetermined intervals in the thickness direction. A method for manufacturing a coil of the motor according to claim 1.

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