Method for manufacturing an electric motor and electric motor

Abstract

This specification describes a method for manufacturing an electric motor, wherein after applying varnish to the welded joint between the coil lead wires and the busbar, the amount of varnish that drips onto the stator core and other parts is reduced. [Solution] The manufacturing method disclosed herein comprises the following steps: (1st step) The lead wires of the stator coil and the ends of the busbars are welded while being held parallel to each other. (2nd step) A varnish receiving member is prepared, which has a through hole through which the welded portion of the lead wires and busbars passes, and a slot connected to the through hole that is smaller than the welded portion but wider than the lead wires and busbars. After passing the welded portion through the through hole of the varnish receiving member, the lead wires and busbars are moved to the end of the slot. (3rd step) While holding the welded portion and the varnish receiving member in a position where the welded portion is above the varnish receiving member, a fluid varnish is applied to the welded portion and the varnish is allowed to solidify.

Description

Technical Field

[0001] The technology disclosed in the present specification relates to a method for manufacturing an electric motor and an electric motor.

Background Art

[0002] The lead wire of the stator coil of an electric motor and the bus bar are welded. In order to reinforce (or protect) the welded portion between the lead wire and the bus bar, varnish is applied to the welded portion (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When varnish is applied to the welded portion, part of the varnish before solidification may drip onto the stator or the like. The present specification provides a method for manufacturing an electric motor that can reduce the amount of varnish that drips onto the stator core or the like. The present specification also provides an electric motor in which the amount of dripping varnish is reduced.

Means for Solving the Problems

[0005] The manufacturing method disclosed in the present specification includes the following steps. (First step) Welding is performed while holding the lead wire of the stator coil and the tip end portion of the bus bar in parallel. (Second step) A varnish receiving member provided with a slot having a width smaller than the welded portion of the lead wire and the bus bar and larger than the lead wire and the bus bar is prepared. The varnish receiving member is attached so that the lead wire and the bus bar pass through the slot. (Third step) While holding the welded portion and the varnish receiving member in an attitude where the welded portion is positioned above the varnish receiving member, fluid varnish is applied to the welded portion, and the varnish is solidified.

[0006] The varnish receiving member catches the dripping varnish. The manufacturing method disclosed herein can reduce the amount of varnish that falls on the stator core and the like compared to conventional manufacturing methods that do not employ a varnish receiving member.

[0007] The varnish receiving member may have a through-hole connected to a slot, which is large enough for the weld to pass through. In this case, in the second step, after passing the weld through the through-hole, the lead wire and busbar are moved to the slot. Alternatively, one end of the slot of the varnish receiving member may be open. In this case, in the second step, the lead wire and busbar are inserted into the slot through the open end. In either case, the lead wire and busbar can be easily guided into the slot.

[0008] The varnish receiving member may have a recess that extends from its upper surface. In this case, in the third step, the varnish is applied while holding the member so that the recess is positioned vertically below the weld. As the varnish that drips down the busbar or leader line accumulates in the recess, the amount of varnish that drips down from the varnish receiving member can be effectively reduced.

[0009] This specification also provides an electric motor that reduces the amount of varnish dripping. The electric motor comprises a stator coil, a busbar, and a varnish receiving member. The busbar's tip is welded to the lead wire of the stator coil. The varnish receiving member has a slot that is smaller than the weld between the lead wire and the busbar but larger than the lead wire and the busbar. The busbar and the lead wire pass through the slot, and the weld between the busbar and the lead wire, as well as a portion of the slot, are covered with varnish.

[0010] The varnish receiving member may have a through-hole connected to the slot, which is large enough for the weld to pass through. Alternatively, the slot of the varnish receiving member may be open at one end. As mentioned above, the lead wires and busbars can be easily guided into the slot.

[0011] The varnish receiving member should have a recess extending from its upper surface. As mentioned above, the varnish that drips down the busbar or leader wire will accumulate in the recess, effectively reducing the amount of varnish that drips down from the varnish receiving member.

[0012] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view of the electric motor with the cover removed (first embodiment). [Figure 2] This is a diagram illustrating the manufacturing method (first step) of an electric motor (first embodiment). [Figure 3] This is a diagram illustrating the manufacturing method (second step) of an electric motor (second embodiment). [Figure 4] This is a diagram illustrating the manufacturing method of an electric motor (third step) (third embodiment). [Figure 5] This is a plan view of a modified example of a varnish receiving member. [Figure 6] This is a cross-sectional view of the varnish receiving member cut along the line VI-VI in Figure 5. [Figure 7] This is a plan view of the electric motor with the cover removed (second embodiment). [Figure 8] This is a diagram illustrating the manufacturing method (second step) of an electric motor (second embodiment). [Figure 9] This is a plan view of a modified example of a varnish receiving member. [Figure 10] This is a cross-sectional view of the varnish receiving member cut along line XX in Figure 9. [Modes for carrying out the invention]

[0014] (First Embodiment) The electric motor 2 of the first embodiment will be described with reference to the drawings. Hereinafter, for the convenience of description, the "electric motor" is simply referred to as "motor". A plan view of the motor 2 is shown on the upper side of Figure 1. Figure 1 is a plan view of the motor 2 with the cover removed. The motor 2 includes a cylindrical housing 3 and a stator core 4 accommodated in the housing 3. The Z-axis of the coordinate system in the drawing coincides with the axial direction of the housing 3 and the stator core 4. The XY plane corresponds to a plane orthogonal to the axis of the stator core 4. In Figure 1, only a part of the housing 3 and the stator core 4 is shown. Further, illustration of the rotor is omitted in Figure 1.

[0015] A plurality of teeth 5 arranged side by side in the circumferential direction are provided on the inner periphery of the cylindrical stator core 4, and a stator coil 6 is wound around each tooth 5. On the lower side of Figure 1, there is shown a cross section of the motor 2 cut along the line A-A in the upper drawing. The lead wire 7 of the stator coil 6 extends parallel to the Z-axis. One end portion of the bus bar 8 (a bus bar tip portion 8a to be described later) is joined to the lead wire 7, and the other end portion 8b of the bus bar 8 extends to the outside of the housing 3. A terminal block 3a is provided on the outer periphery of the housing 3, and the other end portion 8b of the bus bar 8 is fixed to the terminal block 3a with a bolt 9. At the terminal block 3a, the bus bar 8 is connected to a power line (not shown) extending from the inverter.

[0016] The motor 2 includes at least three stator coils, and a bus bar is joined to each of the two lead wires of each stator coil. In Figure 1, only one lead wire 7 and the bus bar 8 are shown, and illustrations of the other lead wires and bus bars are omitted. Hereinafter, the structure in the vicinity of the joint portion between the lead wire 7 and the bus bar 8 will be described in detail. The lead wire 7 and the bus bar 8 are welded, and the joint portion between the lead wire 7 and the bus bar 8 is hereinafter referred to as a welded portion 20.

[0017] One end portion of the lead wire 7 and one end portion of the bus bar 8 are held parallel to each other and welded together. Hereinafter, for convenience of explanation, one end portion of the bus bar 8 is referred to as a bus bar tip portion 8a. A varnish receiving member 10 is attached to the lead wire 7 and the bus bar tip portion 8a. The varnish receiving member 10 includes a through hole 11 and a slot 12 connected to the through hole 12, and the lead wire 7 and the bus bar tip portion 8a pass through the slot 12. As shown in the drawing, the width of the slot 12 is smaller than the welded portion 20 and larger than the lead wire 7 and the bus bar 8. That is, the lead wire 7 and the bus bar 8 can pass through the slot 12, but the welded portion 20 cannot pass through the slot 12. The through hole 11 is larger than the welded portion 20, and the welded portion 20 can pass through the through hole 11. The varnish receiving member 10 reaches the structure of FIG. 1 by moving the lead wire 7 and the bus bar tip portion 8a into the slot 12 after passing the welded portion 20 through the through hole 11.

[0018] The welded portion 20 is covered with a varnish coating 21, and the coating 21 also covers the lead wire 7 and the bus bar tip portion 8a between the welded portion 20 and the varnish receiving member 10. A part of the coating 21 also reaches the varnish receiving member 10. That is, the welded portion 20 is covered with the varnish coating 21, and the coating 21 also covers a part of the varnish receiving member 10. Further, the varnish coating 21 also covers the lead wire 7 and the bus bar tip portion 8a between the welded portion 20 and the varnish receiving member 10. The varnish coating 21 protects the welded portion 20 and increases the strength of the welded portion 20.

[0019] The manufacturing method of the motor 2 will be described with reference to FIGS. 2 to 4. Hereinafter, in particular, the steps from welding of the lead wire 7 and the bus bar tip portion 8a to solidification of the varnish will be described. In FIGS. 2 to 4, only the vicinity of the lead wire 7 and the bus bar tip portion 8a is illustrated. The upper side of FIGS. 2 to 4 shows the welded portion 20 viewed along the axis (Z axis) of the motor 2, and the lower side of FIGS. 2 to 4 shows a cross-sectional view cut along line A-A in the upper drawing.

[0020] (First step) The lead wire 7 of the stator coil 6 and the busbar tip 8a are held parallel to each other and welded (Figure 2). The Z-axis of the coordinate system in the figure is parallel to the lead wire 7. In the welding process, the two are welded together such that, when viewed along the lead wire 7 (when viewed along the Z-axis of the coordinate system in the figure), the size of the welded joint 20 between the lead wire 7 and the busbar tip 8a is larger than the combined area of ​​the lead wire 7 and the busbar tip 8a.

[0021] (Second Step) In the second step, the varnish receiving member 10 is prepared. Note that the varnish receiving member 10 is made in advance, and "preparing the varnish receiving member 10" in the second step means that the varnish receiving member 10 will be used in the second step. The varnish receiving member 10 has a through hole 11 and a slot 12 connected to the through hole. The opening of the through hole 11 and the opening of the slot 12 are connected. The diameter of the through hole 11 is larger than the width of the slot 12. The through hole 11 is large enough for the welded part 20 to pass through. As mentioned earlier, the width of the slot 12 is smaller than the welded part 20 but larger than the leader wire 7 and the busbar 8. In other words, the width of the slot 12 is large enough that the welded part 20 cannot pass through, but the leader wire 7 and the busbar tip 8a can pass through. The varnish receiving member 10 is made of an insulating resin.

[0022] In the second step, after passing the welded portion 20 through the through hole 11 of the varnish receiving member 10, the lead wire 7 and the busbar tip 8a are moved to the end of the slot 12 (the end opposite to the through hole 11) (Figure 3). In Figure 3, the varnish receiving member 10a, drawn with dashed lines, shows the varnish receiving member before it approaches the welded portion 20, and the thick arrow line shows the movement trajectory of the varnish receiving member 10. In the second step, the welded portion 20 may be fixed and the varnish receiving member 10 may be moved, or the varnish receiving member 10 may be fixed and the welded portion 20 (i.e., the entire motor) may be moved.

[0023] (Third step) While holding the welded part 20 and the varnish receiving member 10 in a position where the welded part 20 is positioned above the varnish receiving member 10, a fluid varnish is applied to the welded part 20 and allowed to solidify (Figure 4). In the third step, the position of the welded part 20 and the varnish receiving member 10 is maintained such that the Z axis in Figure 4 is oriented vertically and +Z is oriented vertically upward. Then varnish is applied to the welded part 20. Immediately after application, the varnish is fluid. Some of the fluid varnish travels from the welded part 20 along the leader wire 7 and the busbar tip 8a to the upper surface of the varnish receiving member 10. Some of the varnish remains on the varnish receiving member 10. If the varnish receiving member 10 is not used, a lot of varnish will drip down and adhere to the stator core, etc. The manufacturing method of this embodiment, by employing the varnish receiving member 10, can reduce the amount of varnish that drips onto the stator core, etc., compared to conventional methods. After applying the varnish, the varnish is allowed to harden. The hardened varnish is the varnish film 21.

[0024] The symbol L in Figure 4 indicates the distance between the varnish receiving member 10 and the welded portion 20. When moving the varnish receiving member 10 in the second step, it is preferable to position the varnish receiving member 10 so that the distance L between the welded portion 20 and the varnish receiving member 10 is as short as possible. Due to the surface tension of the varnish, a larger amount of varnish remains between the welded portion 20 and the varnish receiving member 10. As a result, the amount of varnish that drips onto the stator core and the like can be reduced more effectively. If possible, in the second step, it is preferable to move the varnish receiving member 10 so that the welded portion 20 is in contact with the varnish receiving member 10.

[0025] A modified example of the varnish receiving member 110 will be described. Figure 5 shows a plan view of the varnish receiving member 110. Figure 5 also shows the leader wire 7 and busbar tip 8a welded at the weld 20. As mentioned earlier, the leader wire 7 and busbar tip 8a are moved to the slot 12 after passing through the large-diameter through hole 11 at the weld 20.

[0026] Figure 6 is a cross-sectional view of the varnish receiving member 110 along the line VI-VI in Figure 5. The varnish receiving member 110 has a recess 111 that extends from the upper surface 110a of the varnish receiving member 110. In other words, the varnish receiving member 110 has a recess 111 on the surface facing the weld 20. The end of the slot 12 reaches the recess 111. The lead wire 7 and the busbar tip 8a pass through the recess 111. In the third step using this varnish receiving member 110, varnish is applied while holding the recess 111 so that it is positioned below the weld 20 in the vertical direction. A portion of the varnish applied to the weld 20 travels along the lead wire 7 and the busbar tip 8a to the recess 111. A varnish reservoir 22 is formed in the recess 111. Even if a large amount of varnish drips onto the varnish receiving member 110 in the third step, the varnish remains in the depression 111 and does not fall down. The solidified varnish forms the varnish coating 21.

[0027] (Second Embodiment) Next, the motor 202 of the second embodiment will be described using Figures 7 and 8. Figure 7 is a plan view of the motor 202 with the cover removed. The motor 202 of the second embodiment has the same structure as the motor 2 of the first embodiment, except for the varnish receiving member 210. The lower side of Figure 1 shows a cross-section of the motor 2 cut along line AA in the upper figure. The varnish receiving member 10 of the motor 2 of the first embodiment had a through hole 11 and a slot 12 that was closed at both ends. The varnish receiving member 210 of the motor 202 of the second embodiment does not have a through hole, but has a slot 212. The right end of the slot 212 in Figure 7 is closed, but the left end is open. In other words, the varnish receiving member 210 has a U-shape.

[0028] The lead wire 7 and one end of the busbar 8 are held parallel to each other and welded together. Here again, for the sake of explanation, one end of the busbar 8 will be referred to as the busbar tip 8a. A varnish receiving member 210 is attached to the lead wire 7 and the busbar tip 8a. The lead wire 7 and the busbar tip 8a pass through the slot 212 of the varnish receiving member 210.

[0029] The welded joint 20 is covered with a varnish coating 21, and the coating 21 also covers the lead wire 7 and the busbar tip 8a between the welded joint 20 and the varnish receiving member 210. Part of the coating 21 reaches the varnish receiving member 210. The varnish coating 21 also covers the lead wire 7 and the busbar tip 8a between the welded joint 20 and the varnish receiving member 210. The varnish coating 21 protects the welded joint 20 and also increases the strength of the welded joint 20.

[0030] Next, the manufacturing method of motor 202 will be explained. Motor 202 also has a first step (welding of the lead wire 7 and the busbar tip 8a), a second step (installation of the varnish receiving member 210), and a third step (application and solidification of varnish). The first and third steps are the same as in the first embodiment, so their explanation will be omitted. Figure 8 shows an explanatory diagram of the second step.

[0031] In the second step of the manufacturing method of the first embodiment, after passing the welded portion 20 through the through hole 11 of the varnish receiving member 10, the lead wire 7 and the busbar tip 8a were moved to the end of the slot 12 (the end opposite to the through hole 11) (Figure 3). The motor 202 of the second embodiment is prepared with a varnish receiving member 210 having a slot 212 that is open at one end (the left end in Figure 8). Hereinafter, for the sake of explanation, the open end of the slot 212 will be referred to as the open end 213. In the second step of the manufacturing method of the second embodiment, the lead wire 7 and the busbar 8 are inserted into the slot 212 through the open end 213. In Figure 8, the varnish receiving member 210a, drawn with dashed lines, shows the varnish receiving member before it is attached to the lead wire 7 and the busbar 8, and the thick arrow line shows the movement trajectory of the varnish receiving member 210. Since slot 212 has an open end 213, the varnish receiving member 210 can be easily set by moving slot 212 so that it is inserted into the lead wire 7 and busbar 8.

[0032] In the second step, the welded portion 20 may be fixed and the varnish receiving member 210 may be moved, or the varnish receiving member 210 may be fixed and the welded portion 20 (i.e., the entire motor) may be moved. After attaching the varnish receiving member 210 to the lead wire 7 and busbar 8, varnish is applied to the welded portion 20 and allowed to harden (Figure 4).

[0033] Next, a modified example of the varnish receiving member 210 will be described. Figure 9 shows a plan view of the modified varnish receiving member 310. Figure 9 also shows the leader line 7 and busbar tip 8a welded at the weld 20. The leader line 7 and busbar tip 8a pass through the slot 312 of the varnish receiving member 310. Figure 10 is a cross-sectional view of the varnish receiving member 310 along line XX in Figure 9. The varnish receiving member 310 has a recess 311 that is recessed from the upper surface 310a of the varnish receiving member 310. In other words, the varnish receiving member 310 has a recess 311 on the surface facing the weld 20. The end of the slot 312 reaches the recess 311. The leader line 7 and busbar tip 8a pass through the recess 311. In the third step using the varnish receiving member 310, the varnish is applied while the recess 311 is held so that it is positioned vertically below the welded part 20. Some of the varnish applied to the welded part 20 travels along the leader wire 7 and the busbar tip 8a to the recess 311. A varnish reservoir 22 is formed in the recess 311. Even if a lot of varnish drips onto the varnish receiving member 310 in the third step, the varnish remains in the recess 311 and does not fall down. The solidified varnish forms the varnish coating 21.

[0034] The following points should be noted regarding the technology described in the embodiment. The through hole 11 of the varnish receiving member 10 (110) was circular, but the through hole does not have to be circular. The through hole just needs to be large and shaped so that the welded part 20 can pass through. The width of the slot 12 (212) is preferably the same as the width of the wider of the leader wire 7 and the busbar tip 8a. In other words, it is preferable that at least one of the leader wire 7 and the busbar tip 8a is in contact with the inner surface of the slot 12 (212). It is preferable that the leader wire 7 or the busbar tip 8a is in contact with each inner surface of the slot 12 (212). This can reduce the amount of varnish that drips from the gap between the leader wire 7 (or busbar tip 8a) and the slot 12.

[0035] It is preferable that at least one of the leader wire 7 and the busbar tip 8a be positioned in contact with the end of the slot 12 (212) (the end opposite the through hole). This prevents varnish from dripping between the leader wire 7 (or busbar tip 8a) and the end of the slot 12 (212).

[0036] In the third step, the position of the varnish receiving member 10 and the welded portion 20 is maintained such that the welded portion 20 is positioned vertically above the varnish receiving member 10 (210). The first and second steps may be performed in any position.

[0037] The diagram shows only one lead wire 7 and one busbar 8. The stator has at least three coils and at least six lead wires. Each of the multiple lead wires may be accompanied by a varnish receiving member. At least one of the multiple lead wires may be accompanied by a varnish receiving member.

[0038] Although specific examples of the present invention 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 can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of Symbols]

[0039] 2, 202: Electric motor 3: Housing 4: Stator core 5: Teeth 6: Stator coil 7: Lead wire 8: Busbar 8a: Busbar tip 10, 10a, 110, 210, 310: Varnish receiving member 11: Through hole 12, 212: Slot 20: Welded part 21: Coating 22: Varnish reservoir 111, 311: Recess

Claims

1. A method for manufacturing electric motors, The first step involves welding the stator coil lead wires and the busbar tips while holding them parallel to each other, A varnish receiving member is prepared, which has a slot smaller than the welded portion of the lead wire and the busbar and wider than the lead wire and the busbar, and the varnish receiving member is installed so that the lead wire and the busbar pass through the slot. A third step involves holding the welded portion and the varnish receiving member in a position where the welded portion is positioned above the varnish receiving member, applying a fluid varnish to the welded portion, and allowing the varnish to solidify. A manufacturing method that includes [the necessary components / features].

2. The varnish receiving member has a through hole connected to the slot, which is sized to allow the welded portion to pass through. In the second step, after passing the welded portion through the through hole, the leader wire and the busbar are moved to the slot. The manufacturing method according to claim 1.

3. The aforementioned slot is open at one end. In the second step, the leader wire and the busbar are inserted into the slot through the one end. The manufacturing method according to claim 1.

4. The varnish receiving member has a recess that extends from the upper surface of the varnish receiving member, In the third step, the varnish is applied while the recess is held so that it is located below the welded portion in the vertical direction. The manufacturing method according to any one of claims 1 to 3.

5. Stator coil and, A busbar, the tip of which is welded to the lead wire of the stator coil, A varnish receiving member having a slot smaller than the welded portion of the lead wire and the busbar, and having a width larger than the lead wire and the busbar, wherein the lead wire and the busbar pass through the slot of the varnish member, It is equipped with, The welded portion of the busbar and the lead wire, and a portion of the slot are covered with varnish. Electric motor.

6. The varnish receiving member has a through hole connected to the slot, which is sized to allow the welded portion to pass through. The electric motor according to claim 5.

7. The electric motor according to claim 5, wherein one end of the slot is open.

8. The electric motor according to any one of claims 5 to 7, wherein the varnish receiving member has a recess that extends from the upper surface of the varnish receiving member.

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