Rotary electric machine and method for producing rotary electric machine

Abstract

To fix a cover member to a stator core efficiently.SOLUTION: The method for producing a rotary electric machine includes a step of preparing an iron core having a plurality of tooth portions, an arrangement step of arranging insulation paper formed of a foaming material in the plurality of slots, a winding step of winding a coil wire around the iron core so as to form a coil end portion, a mounting step of mounting, on the iron core, a cover member for covering the coil end portion from the outside in an axis direction, the inside in a radial direction, and the outside in the radial direction, and a foaming step of foaming the insulation paper. The cover member has a projection portion that has an annular shape when viewed in the axis direction and is inserted into at least one of the plurality of slots. The foaming step includes forming a pressing state in which the projection portion is pressing the iron core due to the foamed insulation paper.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a rotating electric machine and a method for manufacturing a rotating electric machine. [Background technology]

[0002] A known technique is to provide a base plate or an adapter on the end face of a stator core and a cover member (cooling jacket) that covers the coil end portion of the stator coil, thereby forming an annular space surrounding the coil end portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-271150 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, additional parts (e.g., a base plate or an adapter) are required to fix the cover member to the stator core, which increases the number of parts. In addition, compared to other variations (e.g., variations without a cover member or a base plate), a relatively large change in the process is required, and assembly is significantly deteriorated, which deteriorates manufacturability.

[0005] Therefore, in one aspect, an object of the present disclosure is to efficiently fix a cover member to a stator core. [Means for solving the problem]

[0006] In one aspect, the method includes: preparing an iron core having a plurality of teeth; a placement step of placing insulating paper made of a foam material in a plurality of slots formed between the plurality of teeth portions of the iron core; a winding step of winding a coil wire around the iron core in such a manner that a coil end portion is formed axially outwardly of an axial end surface of the iron core after the arranging step; an assembling process of assembling a cover member, which covers the coil end portion from an axial outer side, a radial inner side, and a radial outer side, to the iron core after the winding process; a foaming step of foaming the insulating paper after the assembling step, the cover member has an annular shape when viewed in the axial direction and has a protrusion portion that is inserted into at least one of the plurality of slots; The foaming step includes forming a pressing state in which the protrusions press the iron core with the foamed insulating paper, the method comprising the steps of: Effect of the Invention

[0007] In one aspect, according to the present disclosure, it is possible to efficiently fix the cover member to the stator core. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a schematic cross-sectional structure of a motor according to an embodiment; [Diagram 2] FIG. [Diagram 3] FIG. 2 is a cross-sectional view of a portion of the stator core. [Figure 4] FIG. 4 is a perspective view of the cover member in a separate state. [Diagram 5] 4 is a plan view of the cover member in a single state (a plan view viewed in the axial direction from the axial outside). FIG. [Figure 6] FIG. 4 is a perspective view of one protrusion portion as viewed from the radially inner side. [Figure 7] 13 is a side view of a protrusion disposed in one slot (between adjacent teeth) as viewed from the radially inner side. FIG. [Figure 8] 1 is a cross-sectional view of one slot (between adjacent teeth) taken along a plane perpendicular to the axial direction at an axial position passing through a protrusion. FIG. [Figure 9] FIG. 1 is a diagram illustrating an example of a cooling system that uses an oil passage. [Figure 10] 4 is a flowchart showing an outline of a method for manufacturing a motor according to the present embodiment. [Figure 11] 4 is a cross-sectional view showing a state in which insulating paper is inserted into a stator core, taken along a plane perpendicular to the axial direction. FIG. [Figure 12] 10 is a cross-sectional view of one slot before foaming of the insulating paper, taken along a plane perpendicular to the axial direction at an axial position passing through a protrusion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting, and shapes and the like in the drawings may be partially exaggerated for the sake of explanation. In addition, in the drawings, for ease of viewing, reference symbols may be given to only some of the parts that exist in a plurality of parts with the same attribute.

[0010] Fig. 1 is a cross-sectional view that shows a schematic cross-sectional structure of a motor 1 according to an embodiment. Fig. 2 is a perspective view of the motor 1. Although Figs. 1 and 2 show only one axial side of the motor 1, the other side may be similar. Fig. 3 is a cross-sectional view of a portion of a stator core 211.

[0011] 1 shows a rotating shaft 12 of a motor 1. In the following description, the axial direction refers to the direction in which the rotating shaft (center of rotation) 12 of the motor 1 extends, the axial outer side refers to the side away from the axial center of the rotor core 32, and the axial inner side refers to the side toward the axial center of the rotor core 32. The radial direction refers to the radial direction centered on the rotating shaft 12, the radial outer side refers to the side away from the rotating shaft 12, and the radial inner side refers to the side toward the rotating shaft 12. The circumferential direction corresponds to the direction of rotation around the rotating shaft 12.

[0012] The motor 1 may be a motor for driving a vehicle, for example, used in a hybrid vehicle or an electric vehicle, but the motor 1 may also be used for any other purpose.

[0013] The motor 1 is housed in and supported by a motor case 10. The motor case 10 may also house a driving element (such as a reduction mechanism) other than the motor 1. The motor case 10 may be formed by combining a plurality of case members. In the example shown in Fig. 1, the motor case 10 includes a case portion 11 that is fitted to the radial outside of the stator 21.

[0014] In this embodiment, the motor 1 is an inner rotor type, and the stator 21 is provided so as to surround the outside of the rotor 30 in the radial direction.

[0015] The radial outer side of the stator 21 is fixed to the motor case 10. The stator 21 includes a stator core 211, a coil wire 22, insulating paper 24, and a cover member .

[0016] Stator core 211 is formed, for example, from laminated steel plates of a circular magnetic material, but may also be formed from a green compact in which magnetic powder is compressed and solidified. Stator core 211 may have an inner peripheral portion and an outer peripheral portion (e.g., a back yoke portion) formed as separate pieces. Stator core 211 may also be formed by combining split cores that are divided in the circumferential direction.

[0017] As shown in Fig. 3, the stator core 211 has teeth portions 214 on the radially inner side at a constant pitch along the circumferential direction. Slots 216 are formed between the teeth portions 214 adjacent to each other in the circumferential direction. The slots 216 are open on both axial sides and also open on the radially inner side. In this embodiment, the teeth portions 214 have a shape in which the circumferential dimension increases at the radially inner end portion 2140. In other words, the teeth portions 214 have a shape in which the radially inner end portion 2140 expands in the circumferential direction.

[0018] The coil wire 22 may be in the form of a conductor wire covered with an insulating coating. The cross section of the coil wire 22 may be any shape, such as a rectangle (rectangular wire) or a circle (round wire). The coil wire 22 is wound around the stator core 211 to form a stator coil. The coil wire 22 may be wound in any way, such as concentrated winding or distributed winding.

[0019] The coil wire 22 is wound around the stator core 211 while being inserted into the slots 216. Then, a coil end portion 223 is formed axially outward from the axial end face of the stator core 211. The coil end portion 223 is formed by a portion of the coil wire 22 that spans between the slots 216 in the circumferential direction (a portion outside the slots 216). The coil end portion 223 is formed on each of both axial sides of the stator core 211. The coil end portion 223 has an annular shape when viewed in the axial direction.

[0020] The insulating paper 24 is disposed between the coil wire 22 and the stator core 211. The insulating paper 24 is made of a foaming material, and is in a foamed state when the motor 1 is in a manufactured state. Before foaming, the insulating paper 24 may be in the form of a sheet including a foam layer that includes a plurality of foam beads, and when foamed, it expands (foams) so as to fill the spaces within the slots 216.

[0021] In a foamed state, the insulating paper 24 fills the space in the slot 216. That is, the insulating paper 24 fills the gap between the coil wire 22 and the stator core 211. In this way, the insulating paper 24 has the function of filling the gap between the coil wire 22 and the stator core 211 in the slot 216. With this function, the insulating paper 24 cooperates with a protrusion 264 of the cover member 26, which will be described later, to prevent oil in the oil passage 80 from flowing axially through the slot 216. In other words, the insulating paper 24 forms a part of the boundary of the oil passage 80. However, in a modified example, the insulating paper 24 may be foamed in a manner that allows a slight amount of oil to leak. Further details of the insulating paper 24 will be described later.

[0022] The cover member 26 surrounds the coil end portion 223. That is, the cover member 26 covers the axially outer side, the radially inner side, and the radially outer side of the coil end portion 223. The cover member 26 may be formed of an insulating material such as a resin material.

[0023] Cover member 26 forms an oil passage 80 (see FIG. 1) that is annular when viewed in the axial direction between the axial end face of stator core 211, coil end portion 223, and insulating paper 24. A seal member 70 (e.g., an O-ring, etc.) may be provided between cover member 26 and case portion 11 of motor case 10 (or stator core 211). Further details of cover member 26 will be described later.

[0024] The rotor 30 is disposed radially inside the stator 21 .

[0025] The rotor 30 includes a rotor core 32 , a rotor shaft 34 , and a permanent magnet 62 .

[0026] The rotor core 32 is fixed to a radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has an axial hole 320 into which the rotor shaft 34 is fitted. The rotor core 32 may be fixed to the rotor shaft 34 by shrink fitting, press fitting, or the like. For example, the rotor core 32 may be joined to the rotor shaft 34 by key joints or spline joints. The rotor shaft 34 is rotatably supported by the motor case 10 via bearings (bearings 14a, etc.). The rotor shaft 34 defines the rotating shaft 12 of the motor 1.

[0027] The rotor core 32 is formed, for example, from laminated steel plates of a magnetic material having a circular ring shape. Permanent magnets may be provided on the inside or radially outer surface of the rotor core 32. In the example shown in Fig. 1, the rotor core 32 has magnet holes 322 penetrating in the axial direction, and permanent magnets 62 are inserted and fixed in the magnet holes 322.

[0028] 1 shows the motor 1 having a specific structure, but the structure of the motor 1 is not limited to such a specific structure. For example, in FIG. 1, the rotor shaft 34 is hollow, but may be solid.

[0029] Next, a characteristic configuration of this embodiment will be described with reference to Figures 1 to 3 as appropriate, and further with reference to Figures 4 to 8. Below, the cover member 26 on one axial side and the configuration related thereto will be mainly described, but the configuration on the other axial side may be similar.

[0030] FIG. 4 is a perspective view of the cover member 26 in a single state. FIG. 5 is a plan view of the cover member 26 in a single state (plan view viewed in the axial direction from the axial outside). FIG. 6 is a perspective view of one protrusion 264 viewed from the radial inside. FIG. 7 is a side view of the protrusion 264 of the cover member 26 arranged in one slot 216 (between adjacent teeth 214) viewed from the radial inside. In FIG. 7, for ease of viewing, the cover member 26 is hatched. FIG. 8 is a cross-sectional view of one slot 216 (between adjacent teeth 214) when cut by a plane perpendicular to the axial direction at an axial position passing through the protrusion 264 of the cover member 26. FIG. 9 is a diagram showing an example of a cooling system 7 using an oil passage 80.

[0031] As shown in Fig. 4 and Fig. 5, the cover member 26 has an annular shape when viewed in the axial direction. The cover member 26 has a top surface portion 2630 on the axially outer side, a peripheral surface portion 2631 on the circumferentially outer side, and a peripheral surface portion 2632 on the circumferentially inner side, which form a C-shape when viewed in a cross section (see Fig. 1) along a plane passing through the rotating shaft 12. The top surface portion 2630 and the peripheral surface portions 2631 and 2632 of the cover member 26 may have substantially the same C-shape when viewed in a cross section (see Fig. 1) along a plane passing through the rotating shaft 12 at each circumferential position of a circumferential section other than the circumferential section in which the cylindrical portions 261 and 262 described later are provided. The cover member 26 forms an oil passage 80 by a C-shaped space portion formed by the top surface portion 2630 and the peripheral surface portions 2631 and 2632.

[0032] The cover member 26 has hollow cylindrical portions 261, 262 on a peripheral surface portion 2631 on the circumferential outer side. The hollow cylindrical portions 261, 262 communicate with the inside of the cover member 26 (the space on the coil end portion 223 side). The hollow cylindrical portions 261, 262 form an inlet 81 and an outlet 82 of an oil passage 80 (see also FIG. 1). The cylindrical portions 261, 262 may be provided diagonally relative to each other. For example, the cylindrical portion 261 may be connected to an oil passage 83 (FIG. 9) on the discharge side of the oil pump 90, and the cylindrical portion 262 may be connected to an oil passage 84 (FIG. 9) on the suction side of the oil pump 90.

[0033] The circumferentially outer peripheral surface portion 2631 has an axially inner end portion that abuts against or engages with the case portion 11 (or the stator core 211) of the motor case 10. The circumferentially outer peripheral surface portion 2631 may be fitted into the case portion 11 (or the stator core 211) of the motor case 10 in a manner that there is a radial engagement between the case portion 11 (or the stator core 211) of the motor case 10.

[0034] Except for a circumferential section having protrusions 264 described later, the axially inner end face of circumferentially inner peripheral surface portion 2632 abuts on the axial end face of stator core 211. Note that a groove or the like into which an axially inner end portion of circumferentially inner peripheral surface portion 2632 fits may be provided on the axial end face of stator core 211. Also, a seal member may be provided between the axial end face of stator core 211 and the axially inner end portion of circumferentially inner peripheral surface portion 2632.

[0035] The cover member 26 has protrusions 264 that are inserted into the slots 216. In this embodiment, a protrusion 264 is provided for each slot 216. However, in a modified example, the cover member 26 may have protrusions 264 in a number less than the number of slots 216, with the protrusions 264 being inserted into some of all of the slots 216. In this case as well, the protrusions 264 are preferably provided at equal pitches in the circumferential direction.

[0036] The protrusion 264 protrudes axially inward from an axially inner edge of a peripheral surface portion 2632 on the radially inner side of the cover member 26. The axial length of the protrusion 264 (the length inserted into the slot 216) is arbitrary, but may be adapted to be a relatively small length within a range in which the fixing function described below is appropriately achieved.

[0037] The protrusion 264 is inserted into the radially inner end of the slot 216. The protrusion 264 inserted into one slot 216 is located radially inward from the portion of the coil wire 22 inserted into that one slot 216. The protrusion 264 has a circumferential width larger than the circumferential width of the radially inner end of the slot 216 (the radially inner opening width). In other words, the protrusion 264 closes the radially inner opening of the slot 216.

[0038] The protrusions 264 have the function of fixing the cover member 26 to the stator core 211 by being pressed by the foamed insulating paper 24 .

[0039] Specifically, in this embodiment, the insulating paper 24 is formed of a foaming material as described above, and foams in the slot 216. Since the protrusion 264 blocks the opening on the radial inner side of the slot 216 as described above, the insulating paper 24 is prevented from foaming completely in the slot 216 into which the protrusion 264 is inserted. That is, foaming of the insulating paper 24 that tries to expand radially inward through the opening on the radial inner side of the slot 216 is prevented. Therefore, as shown diagrammatically by a force F8 in FIG. 8, the insulating paper 24 presses the protrusion 264 toward the stator core 211. The protrusion 264 engages with the end 2140 on the radial inner side of the tooth portion 214, and receives a reaction force of the force F8 from the tooth portion 214. As a result, the cover member 26 is fixed to the stator core 211 due to the force F8.

[0040] The configuration of the insulating paper 24 (such as its thickness and foaming rate) may be adapted so that a force F8 sufficient to fix the cover member 26 to the stator core 211 is generated. The shape of the insulating paper 24 before foaming may be constant along the axial direction, but the axial range in which the protrusions 264 are arranged may have a different shape from the other axial ranges. For example, the volume of the insulating paper 24 in the axial range in which the protrusions 264 are arranged may be adjusted to be larger than the volume of the insulating paper 24 in the other axial ranges.

[0041] In this manner, according to the present embodiment, the cover member 26 can be fixed to the stator core 211 by utilizing the insulating paper 24 made of a foam material. This eliminates the need for additional parts or structures for fixing the cover member 26 to the stator core 211. Therefore, according to the present embodiment, the cover member 26 can be efficiently fixed to the stator core 211. Furthermore, the insulating paper 24 made of a foam material, together with the protrusion 264, closes the radially inner opening of the slot 216 and fills the gap between the coil wire 22 and the stator core 211 in the slot 216. Therefore, according to the present embodiment, an annular space surrounding the coil end portion 223 can be efficiently formed.

[0042] Referring to FIG. 9, the cooling system 7 can cool the coil end portion 223 via the oil passage 80 and can also directly recover heat from the coil end portion 223. The recovered heat may be dissipated via any heat dissipation means (such as an oil cooler), but is preferably supplied to the battery 100 at low temperatures. This allows the temperature of the battery 100 to be increased by utilizing the heat from the coil end portion 223 in a low-temperature environment. The cooling system 7 may be provided with a switchable path between supplying the heat from the coil end portion 223 to the battery 100 and supplying the heat to another heat dissipation means (such as an oil cooler). In this case, the temperature of the battery 100 can be increased by utilizing the heat from the coil end portion 223 only when the temperature of the battery 100 is equal to or lower than a threshold value. The heat from the coil end portion 223 may be used in an air conditioning system (not shown) instead of or in addition to the battery 100. In a modified example, the battery 100 may be heated by supplying the battery 100 with heated cooling water via an oil cooler. In this case, in the oil cooler, heat exchange takes place between the oil passage 80 and the cooling water, so that the heat of the coil end portion 223 can be used to raise the temperature of the cooling water relatively quickly.

[0043] Next, a method for manufacturing the motor 1 according to this embodiment will be described with reference to FIGS.

[0044] Fig. 10 is a flow chart showing a schematic flow of a manufacturing method of the motor 1 according to this embodiment. Fig. 11 is a cross-sectional view taken along a plane perpendicular to the axial direction, showing a state in which the insulating paper 24 is inserted into the stator core 211. Fig. 12 is a cross-sectional view taken along a plane perpendicular to the axial direction at an axial position passing through the protrusion 264, showing one slot 216 (between adjacent teeth 214) before the insulating paper 24 is foamed.

[0045] This manufacturing method first includes a step (step S91) of preparing the stator core 211, the cover member 26, the coil wire 22, the insulating paper 24, etc. For example, when the coil wire 22 is a rectangular wire, the coil material may be shaped into a predetermined shape by various bending processes or the like to prepare the coil wire 22. The insulating paper 24 is prepared in a state before being foamed.

[0046] Next, the manufacturing method includes an arrangement step (step S92) of inserting insulating paper 24 into slots 216 of stator core 211. As shown in Fig. 11, insulating paper 24 may be arranged around the peripheral wall (boundary wall) of slot 216 for each slot 216 so as to form a space into which coil wire 22 is inserted. Note that insulating paper 24 may be arranged in a manner such that it slightly protrudes axially outward from the axial end face of stator core 211.

[0047] Next, the manufacturing method includes a winding process (step S93) of winding the coil wire 22 around the stator core 211.

[0048] Next, the manufacturing method includes a stator coil finishing step (step S94). The stator coil finishing step is optional, but may include, for example, when the coil wire 22 is a rectangular wire, a joining process of the ends of the coil wire 22, an insulation process of the joint, an assembly process of a neutral wire, a bus bar for a power line, and the like.

[0049] Next, this manufacturing method includes an assembly process (step S95) of assembling the cover member 26 to the stator core 211. At this time, the protrusions 264 are inserted into each slot 216. Fig. 12 is a schematic cross-sectional view showing the state inside one of the slots 216 when step S95 is completed. Note that at this stage, the insulating paper 24 is in a pre-foamed state, and a space (gap) S exists between the coil wire 22 and the stator core 211 inside the slot 216.

[0050] Next, the manufacturing method includes a foaming step (step S96) of foaming the insulating paper 24. This step may be realized, for example, by raising the temperature of the workpiece that has been through step S95 to a temperature at which the insulating paper 24 foams. When the insulating paper 24 foams, the state inside the slot 216 shown in FIG. 12 changes to the state inside the slot 216 shown in FIG. 8 described above. That is, the space S shown in FIG. 12 is filled with the insulating paper 24, and the gap between the coil wire 22 and the stator core 211 in the slot 216 is filled. Furthermore, as described above with reference to FIG. 8, the insulating paper 24 presses the cover member 26, thereby firmly fixing the cover member 26 to the stator core 211.

[0051] In this manner, according to the present manufacturing method, the insulating paper 24 made of a foaming material is foamed, so that the cover member 26 can be fixed to the stator core 211. This eliminates the need for a process of assembling additional parts for fixing the cover member 26 to the stator core 211. Therefore, according to this embodiment, the cover member 26 can be efficiently fixed to the stator core 211. Furthermore, by foaming the insulating paper 24 made of a foaming material, the insulating paper 24 can press the protruding portion 264 radially outward to close the radially inner opening of the slot 216, and the insulating paper 24 can fill the gap between the coil wire 22 and the stator core 211 in the slot 216. Therefore, according to this embodiment, an annular space surrounding the coil end portion 223 can be efficiently formed.

[0052] Furthermore, according to this manufacturing method, the various steps (steps S91 to S94) prior to the step (step S95) of assembling cover member 26 to stator core 211 can be the same as those for other variations of motors (not shown) that do not include cover member 26. As a result, this manufacturing method does not require significant changes to the manufacturing steps for other variations, and can be realized by efficiently utilizing manufacturing equipment for motors of other variations.

[0053] Although each embodiment has been described above in detail, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of the components of the above-described embodiments.

[0054] For example, the above-mentioned embodiment is an example of application to the stator 21, but it can also be applied to a wound field rotor on which a coil wire is wound. In this case, the coil end portion formed on the radially outer side of the rotor core can be surrounded by a similar cover member. In this case, the cover member has a similar protrusion, and can be fixed to the rotor core by the expansion of the insulating paper. In this case, the cover member can cool the coil wire of the rotor by forming an oil passage. [Explanation of symbols]

[0055] 1 motor (rotating electric machine), 211 stator core (iron core), 214 teeth portion, 2140 end portion (radially inner end portion), 216 slot, 22 coil wire, 223 coil end portion, 24 insulating paper, 26 cover member, 264 projection portion, 80 oil passage

Claims

1. preparing an iron core having a plurality of teeth; a placement step of placing insulating paper made of a foam material in a plurality of slots formed between the plurality of teeth portions of the iron core; a winding step of winding a coil wire around the iron core in such a manner that a coil end portion is formed axially outwardly of an axial end surface of the iron core after the arranging step; an assembling process of assembling a cover member, which covers the coil end portion from an axial outer side, a radial inner side, and a radial outer side, to the iron core after the winding process; a foaming step of foaming the insulating paper after the assembling step, The cover member has an annular shape when viewed in the axial direction, and has a protrusion portion that is inserted into at least one of the plurality of slots, The foaming step includes forming a pressing state in which the protrusion presses the iron core with the foamed insulating paper.

2. The teeth have a shape in which a circumferential dimension increases at a radial end portion, The method for manufacturing a rotating electric machine according to claim 1 , wherein the pressing state includes a state in which the protrusions press radially against radial ends of the teeth portions adjacent to each other in the circumferential direction.

3. 3. The method for manufacturing a rotating electric machine according to claim 1, wherein the foaming step includes forming the insulating paper so as to fill a gap between the iron core and the coil wire in the slot.

4. an iron core having a plurality of teeth; an insulating paper formed of a foamed material and disposed in a plurality of slots formed between the plurality of teeth portions of the iron core; a coil wire wound around the iron core and forming a coil end portion on the axially outer side with respect to an axial end face of the iron core; a cover member that covers the coil end portion from an axially outer side, a radially inner side, and a radially outer side, the cover member has a protrusion that is inserted into at least one of the slots; The protrusion is pressed against the iron core by the insulating paper.

5. The teeth have a shape in which a circumferential dimension increases at a radial end portion, The rotating electric machine according to claim 4 , wherein the protrusions radially press against radial ends of the teeth portions adjacent to each other in the circumferential direction.

6. The rotating electric machine according to claim 4 , wherein the cover member forms an oil passage that is annular when viewed in the axial direction between the axial end face of the iron core, the coil end portion, and the insulating paper.

7. The rotating electric machine according to claim 4 , wherein the insulating paper fills a gap between the iron core and the coil wire in the slot.

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