Stator of electric motor and method for manufacturing stator of electric motor

Abstract

The purpose of this invention is to suppress angular deviation at the shoulder of the segment coil and improve the insertion of the segment coil into the stator core. The stator of the electric motor of this invention comprises a stator core (12) having multiple armature slots (12a) and multiple segment coils (11) formed in a U-shape and inserted into the multiple armature slots (12a). Each segment coil (11) has a shoulder (11a) and a shoulder (11b) formed by bending to form a U-shape. When viewed from the front in the U-shape state, indentations (100a) are formed on the shoulder (11a) and shoulder (11b) in a front-rear direction, recessed from the surface of the shoulder (11a) and the surface of the shoulder (11b). Furthermore, indentations (100a) are also formed on the back of the shoulder (11a) and shoulder (11b).

Description

Technical Field

[0001] This invention relates to a stator for an electric motor and a method for manufacturing the stator. Background Technology

[0002] Vehicle drive motors require small size, lightweight, high power, and high efficiency. To meet these performance requirements, a technique exists where multiple segmented coils made of flat wire are inserted into the stator core and their ends are welded together. Stators primarily used in electric vehicles require a long, cylindrical shape for high-speed operation, leading to a trend towards thicker stator core layers. Consequently, the length of the segmented coils inserted into the stator core must be increased to match the core's layer thickness.

[0003] Conventionally, segmented coils are formed having a coil end vertex, a coil end conductor ramp, and a conductor straight portion. The coil end conductor ramp is located on both sides of the coil end vertex, and the conductor straight portion extends from the coil end conductor ramp in the opposite direction to the coil end vertex. Furthermore, a shoulder is formed between the coil end conductor ramp and the conductor straight portion. Segmented coils are formed by bending a flat conductor using a jig and a forming die.

[0004] As a method for forming segmented coils, for example, the techniques described in Patent Documents 1 to 3 have been proposed.

[0005] In Patent Documents 1 and 2, a coil end forming portion is formed by installing wire between a first forming mold and a second forming mold. For the outer portion relative to this coil end forming portion, two forming rollers descend along the side of the second forming mold to form two armature slot insertion portions (conductor straight portions). The angle of the shoulder portion, which is bent by the forming rollers, determines the distance between the open ends of the armature slot insertion portions. Since the distance between the open ends of the armature slot insertion portions changes due to springback, when forming the armature slot insertion portions using the forming rollers, the bending angle of the shoulder portion is increased to account for the springback, relative to the target bending angle, so that the angle of the shoulder portion becomes the target angle.

[0006] Furthermore, in Patent Document 3, a cam structure device is used to form the final angle of the shoulder, which increases the bending by a factor of anticipating the springback compared to the target bending angle of the shoulder, thus making the shoulder angle the target angle. Therefore, in Patent Document 3, the spacing dimension of the open end of the armature slot receiving portion is ensured by the angle of the formed shoulder.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2004-297863

[0010] Patent Document 2: Japanese Patent Application Publication No. 2014-135857

[0011] Patent Document 3: Japanese Patent Application Publication No. 2010-246283 Summary of the Invention

[0012] The problem the invention aims to solve

[0013] The spacing between the open ends of the armature slots of the segmented coils may deviate.

[0014] The distance between the open ends of the armature slot insertion parts is determined by the angle of the shoulder, so deviations in the shoulder angle will affect the deviations in the distance between the open ends of the armature slot insertion parts.

[0015] In stators used in electric vehicles, there is a trend towards increasing stator core lamination thickness. As the stator core lamination thickness increases, the length of the armature slot insertion portion of the segmented coils correspondingly increases. When the length of the armature slot insertion portion increases, the deviation in the distance between the open ends of the armature slot insertion portions increases.

[0016] In the technology described in Patent Documents 1 to 3, although the rebound amount is taken into account to adjust the angle of the shoulder, the deviation of the open end spacing of the armature slot insertion parts corresponding to the case of the armature slot insertion part becoming longer is not taken into account.

[0017] Therefore, due to the deviation in the distance between the open ends of the armature slot insertion parts, when the section coil is inserted into the armature slot of the stator core, the armature slot insertion part of the section coil comes into contact with the side of the stator core. If the armature slot is filled with insulating paper, there is a problem of damage to the insulating paper.

[0018] Furthermore, the contact between the armature slot insertion part of the section coil and the stator core and insulating paper will increase the insertion load of the section coil, thus requiring a load higher than necessary to insert the section coil. This can lead to deformation of the section coil itself, making it difficult to insert the section coil.

[0019] To account for deviations in the spacing between the open ends of the armature slot insertion portions and to minimize contact between the stator core and the section coils, methods exist to increase the size of the armature slots, thereby increasing the gap between the stator core and the section coils and improving the insertion capability of the section coils. However, in this case, the proportion of the section coils within the armature slots decreases, resulting in a reduction in motor performance.

[0020] The angular deviation at the shoulder of a segmented coil is caused by variations in the hardness of the copper used to make the segmented coil, its position on the coil frame, differences in the processing stress applied when straightening the coil, and variations in coil dimensions, all of which cause changes in the amount of springback relative to the bending angle. Therefore, for segmented coils, after shaping the coil wound on the coil frame into a straight line through bending, the deviation in springback is adjusted by changing the bending angle of the shoulder to a specified range.

[0021] The adjustment varies depending on the state of the section coils. If the spacing dimensions are not within the range, an adjustment must be made every time, which is time-consuming and reduces the productivity of the adjustment.

[0022] The purpose of this invention is to provide a stator for an electric motor that suppresses angular deviation at the shoulder of the segment coil and improves the insertion of the segment coil into the stator core, as well as a method for manufacturing the stator for the electric motor.

[0023] Technical means to solve the problem

[0024] To achieve the above objectives, the present invention provides a stator for an electric motor, comprising a stator core having a plurality of armature slots and a plurality of segment coils formed in a U-shape and inserted into the plurality of armature slots. The stator of the electric motor is characterized in that the segment coils have a first curved portion and a second curved portion formed by bending to form a U-shape, and when the U-shape is viewed from the front, indentations are formed on the first curved portion and the second curved portion in a front-back direction from one side of the first curved portion and the other side of the second curved portion.

[0025] Furthermore, this invention relates to a method for manufacturing a stator for an electric motor. Multiple segmented coils, shaped like a U-shape, are inserted into multiple armature slots formed on a stator core. The method is characterized in that each segmented coil has a first curved portion and a second curved portion formed by bending to form a U-shape. When the U-shape is viewed from the front, indentations are formed on the first and second curved portions, extending in a front-to-back direction from one side of the first curved portion, one side of the second curved portion, and the opposite side to the first and second curved portions. These indentations are formed by an indentation forming device, which includes: an upper punch that forms an indentation on one side of the segmented coil; a pressing plate having the upper punch and applying pressing force to the upper punch; and an upper workpiece pressure plate formed to control the movement of the upper punch. The device comprises: an upper guide hole for guiding; a lower punch that forms an indentation on the other side of the segment coil; a base plate having the lower punch and applying pressing force to the lower punch; a lower workpiece pressure plate having a lower guide hole for guiding the movement of the lower punch; and a guide pin for adjusting the angles of the first curved portion and the second curved portion of the segment coil. The indentation forming apparatus includes the following steps: placing the segment coil on the lower workpiece pressure plate; moving the upper workpiece pressure plate toward the lower workpiece pressure plate to fix the segment coil; actuating the guide pin to adjust the angles of the first curved portion and the second curved portion of the segment coil to a target angle; applying a load to the pressure plate to form the indentation on the first curved portion and the second curved portion of the segment coil; releasing the load on the pressure plate; and moving the upper workpiece pressure plate away from the lower workpiece pressure plate.

[0026] The effects of the invention

[0027] According to the present invention, a stator for an electric motor and a method for manufacturing the stator for an electric motor are provided, which suppresses angular deviation at the shoulder of the segment coil and improves the insertion of the segment coil into the stator core. Attached Figure Description

[0028] Figure 1 This is a perspective view showing the state in which the section coil related to Embodiment 1 of the present invention is temporarily inserted into the stator core of the motor.

[0029] Figure 2 This is a perspective view showing the state in which the section coil related to Embodiment 1 of the present invention has been inserted into the stator core of the motor.

[0030] Figure 3A The images show a top view and a front view of the section coil 11 related to Example 1.

[0031] Figure 3B for Figure 3AEnlarged view of the main part of IIIB in the diagram.

[0032] Figure 3C for Figure 3A Enlarged view of the main part of IIIC in the image.

[0033] Figure 4A A cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the section coil 11 is inserted into the center portion of the armature slot 12a.

[0034] Figure 4B A partial cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the section coil 11 is inserted into the side of the armature slot 12a.

[0035] Figure 4C A cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the section coil 11 is inserted obliquely into the armature slot 12a.

[0036] Figure 5A An enlarged view of the main part showing the bending angle of the shoulder 11a as the target.

[0037] Figure 5B An enlarged view of the main part showing the bending angle of the shoulder 11a after bending processing.

[0038] Figure 5C An enlarged view of the main part showing the bending angle of the adjusted shoulder 11a.

[0039] Figure 6A A magnified view of the front of the section coil before bending.

[0040] Figure 6B for Figure 6A The VIB-VIB line cross-section diagram.

[0041] Figure 7A This is a magnified view of the front of the section of coil before the indentation is formed after bending.

[0042] Figure 7B for Figure 7A The cross-sectional view of line VIIB-VIIB in the diagram.

[0043] Figure 8A This is a magnified view of the front of the coil section after the indentation has been formed.

[0044] Figure 8B for Figure 8A The cross-sectional view of line VIIIB-VIIIB in the diagram.

[0045] Figure 9 To Figure 6B , Figure 7B , Figure 8B A graph comparing the film thickness of the coil segments in the diagram.

[0046] Figure 10 A diagram showing the relationship between the spacing between the open ends 11m and 11n of the straight section of the conductor and the depth of the indentation 100a.

[0047] Figure 11A This is an enlarged view of the main part at the shoulder 11a of the section coil 11 related to Example 2.

[0048] Figure 11B This is an enlarged view of the main part at the shoulder 11a of the section coil 11 related to Example 2.

[0049] Figure 12A This is an enlarged view of the main part at the shoulder 11a of the section coil 11 related to Example 3.

[0050] Figure 12B This is an enlarged view of the main part at the shoulder 11a of the section coil 11 related to Example 3.

[0051] Figure 13 This is an enlarged view of the main part at the shoulder 11a of the section coil 11 related to Example 4.

[0052] Figure 14A This is a cross-sectional view of the main part of the indentation forming device 200.

[0053] Figure 14B This is a cross-sectional view of the main part of the indentation forming device 200.

[0054] Figure 15 This is a flowchart illustrating the indentation forming process performed by the indentation forming apparatus 200. Detailed Implementation

[0055] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The same reference numerals will be used to denote the same constituent elements, and the same descriptions will not be repeated.

[0056] The various constituent elements of the present invention do not necessarily have to exist independently. It is permissible for one constituent element to be composed of multiple components, multiple constituent elements to be composed of one component, one constituent element to be part of another constituent element, or a part of one constituent element to be repeated with a part of another constituent element.

[0057] Example 1

[0058] The structure of the stator of the electric motor is described. Figure 1 This is a perspective view showing the state in which the section coil related to Embodiment 1 of the present invention is temporarily inserted into the stator core of the motor. Figure 2This is a perspective view showing the state in which the section coil related to Embodiment 1 of the present invention has been inserted into the stator core of the motor.

[0059] The electric motor consists of a rotor (not shown) and a stator 10. The stator 10 has a stator core 12 formed by multiple layers of electromagnetic steel plates, multiple armature slots 12a formed in the stator core 12, and segment coils 11 inserted into the armature slots 12a.

[0060] The segment coil 11 is formed into a U-shape by bending the wire. For multiple segment coils 11 formed into a U-shape, like... Figure 1 As shown, the section coil 11 is inserted into the armature slot 12a by pressing the open end toward the armature slot 12a of the stator core 12 and pressing from the bottom of the U-shape. Furthermore, as... Figure 2 As shown, the section coil 11 is housed in the armature slot 12a of the stator core 12 with its open end protruding from the armature slot 12a.

[0061] Next, use Figures 3A to 3C The structure of section coil 11 will be explained. Figure 3A The above view and front view are of the section coil 11 related to Embodiment 1. Figure 3B for Figure 3A Enlarged view of the main part of IIIB in the figure. Figure 3C for Figure 3A The enlarged view of the main part of IIIC is shown in Example 1. As an example of the segment coil 11, an enamel-coated wire is used as an example, but as long as the wire is a conductor made of metal, it can also be made of other metals such as aluminum or iron.

[0062] like Figures 3A to 3C As shown, the segment coil 11 is formed by shaping a straight, flat conductor using a forming mold and fixture (not shown), resulting in shoulders 11a (first curved portion) and shoulders 11b (second curved portion) bent to form a U-shape, and the coil end vertex 11c forming the bottom of the U-shape. Shoulders 11a and 11b are formed by edge bending, where the long side of the flat conductor's cross-section is bent laterally. Regarding the dimensions of the segment coil 11 in Embodiment 1, the thickness T in the bending direction is set to 3.6 mm, and the width W in the bending width direction is set to 2.6 mm. The segment coil 11 is thus formed into a U-shape. Furthermore, on the U-shaped segment coil 11, there are coil end bends 11d, coil end conductor oblique portions 11e and 11f that are located on both sides of the coil end vertex 11c and are inclined from the coil end vertex 11c, conductor straight portions 11g and 11h that extend from the shoulders 11a and 11b, and open ends 11m and 11n that become the tops of the conductor straight portions 11g and 11h.

[0063] The section coil 11 has a curved portion and a straight portion connected to the curved portion. The curved portion is composed of shoulder portions 11a and 11b, coil end vertex 11c, coil end bend portion 11d, and coil end conductor oblique portions 11e and 11f. The straight portion is composed of conductor straight portions 11g and 11h, and open ends 11m and 11n.

[0064] The straight conductor portion 11g and the open end 11m are inserted into one of the multiple armature slots 12a. The straight conductor portion 11h and the open end 11n are inserted into another armature slot 12a that is different from the one into which the straight conductor portion 11g and the open end 11m are inserted. The angle of the shoulder portion 11a is θ1, and the angle of the shoulder portion 11b is θ2. Angles θ1 and θ2 determine the spacing between the open ends 11m and 11n. Furthermore, in the U-shaped state viewed from the front, indentations 100a and 100b are formed on the shoulders 11a and 11b of the segment coil 11, extending in the front-to-back (depth) direction from one side of the shoulder portion 11a and the other side of the shoulder portion 11b. Indentations 100a and 100b are also formed in the front-to-back (depth) direction on the opposite side (back side) to one side (surface) of the shoulder portion 11a and the other side (surface) of the shoulder portion 11b. That is, indentations 100a and 100b are formed on both the surface and back of the shoulders 11a and 11b. Details of indentations 100a and 100b will be described later.

[0065] As described above, the straight conductor portion 11g and the straight conductor portion 11h are inserted into different armature slots 12a. Therefore, when inserting the segment coil 11 into the armature slot 12a, it is important to suppress the deviation in the spacing between the open ends 11m and 11n on the straight conductor portions 11g and 11h of the segment coil 11. In particular, when the straight conductor portions 11g and 11h become longer, the deviation in the spacing between the open ends 11m and 11n of the straight conductor portions 11g and 11h increases.

[0066] use Figures 4A to 4C The state of inserting section coil 11 into armature slot 12a will be explained. Figures 4A to 4C The image shows the state of the conductor straight section 11g side when the conductor straight section 11g is inserted into the armature slot 12a while being positioned on the open end 11n side.

[0067] Figure 4A A cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the section coil 11 is inserted into the center portion of the armature slot 12a. Figure 4B This is a partial cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the segment coil 11 is inserted into the side of the armature slot 12a. Figure 4CA cross-sectional view of the stator core 12 showing the state in which the straight conductor portion 11g of the section coil 11 is inserted obliquely into the armature slot 12a.

[0068] The stator core 12 is formed by stacking multiple electromagnetic steel plates. Multiple armature slots 12a are formed on the stator core 12 by passing through the stacked electromagnetic steel plates. Insulating paper 13 is provided in the armature slots 12a along the side 12b of the armature slots 12a.

[0069] Figure 4A In this configuration, with the spacing accuracy of the open ends 11m and 11n of the straight conductor portions 11g and 11h being good, the open ends 11m (11n) do not contact the insulating paper 13. The straight conductor portion 11g of the segment coil 11 is inserted in such a manner that a predetermined clearance 14 is maintained between the straight conductor portion 11g of the segment coil 11 and the side surface 12b of the armature slot 12a. In this state, the duty cycle of the segment coil 11 within the armature slot 12a is increased, thus providing a high-efficiency electric motor.

[0070] On the other hand, if there is a deviation in the dimensional accuracy of the spacing between the open ends 11m and 11n of the straight sections 11g and 11h of the conductors, it becomes... Figure 4B , Figure 4C It looks like that.

[0071] Figure 4B In this configuration, the straight conductor portion 11g of the segment coil 11 is inserted with its side biased towards the armature slot 12a, and a portion of the straight conductor portion 11g contacts the insulating paper 13. Where the straight conductor portion 11g does not contact the insulating paper 13, the clearance 14 increases. When the segment coil 11 is inserted with the straight conductor portion 11g in contact with the insulating paper 13, friction increases, and the insertion load further increases. Therefore, the dimensional accuracy of the spacing between the open ends 11m and 11n is crucial.

[0072] Figure 4C In the middle, at the angles θ1 of shoulder 11a and θ2 of shoulder 11b (reference) Figure 3C When deviating from the target angle, the straight portion 11g of the conductor becomes inclined relative to the side 12b of the armature slot 12a, and the open end 11m of the straight portion 11g contacts the insulating paper 13. When the straight portion 11g of the conductor is further inserted in this state, as the insertion depth increases, the inclined straight portion 11g of the conductor becomes aligned with the side 12b of the armature slot 12a, so the deformation load and contact pressure of the straight portion 11g of the conductor increase, which will be added to the insertion load, thus further increasing the insertion load. In addition, the inclined straight portion 11g of the conductor may damage the insulating paper 13.

[0073] Next, use Figures 5A to 5CThe method for adjusting the spacing between the open ends 11m and 11n is explained. Figure 5A An enlarged view of the key part showing the bending angle of the shoulder 11a as the target. Figure 5B This is an enlarged view showing the bending angle of the shoulder 11a after bending. Figure 5C An enlarged view of the main part showing the bending angle of the adjusted shoulder 11a.

[0074] The bending angle of the shoulder 11a is determined by changing the spacing between the open ends 11m and 11n of the segment coil 11 to a predetermined size. In Embodiment 1, like... Figure 5A As shown, the angle θ1 of the shoulder 11a is set as the target angle. During the bending process of the segment coil 11, springback occurs in the bent portion as it attempts to return to its original shape. Therefore, at the shoulder 11a, the amount of springback is considered and... Figure 5B As shown, the shoulder 11a is bent to an angle θ3 (θ1 > θ3) that is smaller than the target angle θ1. Then, the segment coil 11 is released from the molding die and fixture with the shoulder 11a at an angle of angle θ3.

[0075] Next, the segment coil 11 released from the molding die and fixture is installed into the indentation forming apparatus described later. The indentation forming apparatus is equipped with guide pins 40a to 40d for adjusting the angle of the shoulder 11a of the segment coil 11. Guide pins 40a and 40b are configured to clamp the inclined portion 11e of the coil end conductor, and guide pins 40c and 40d are configured to clamp the straight portion 11g of the conductor. With the inclined portion 11e of the coil end conductor and the straight portion 11g of the conductor clamped by guide pins 40a and 40b, and guide pins 40c and 40d respectively, the guide pins 40c and 40d are moved by increasing the angle of the shoulder 11a, thereby moving the straight portion 11g of the conductor. Subsequently, guide pins 40c and 40d stop at the position where the angle of shoulder 11a is angle θ3', and the angle of shoulder 11a is set as the target angle, i.e., angle θ1 (θ1 = θ3').

[0076] With the angle of shoulder 11a fixed at angle θ3' (θ1), an indentation 100a is formed on shoulder 11a. The indentation 100a is formed by pressing the surface of segment coil 11 with a punch or the like, causing the width W of segment coil 11 to become smaller than other parts. After forming indentations 100a and 100b, when segment coil 11 is released from the indentation forming device, the angle of shoulder 11a is fixed at angle θ3' (θ1).

[0077] At the shoulder 11a, external pressure causes plastic deformation of the material. Material flow and work hardening alter the shape, thus fixing the angle θ1 of the shoulder 11a. Although the description is omitted, it is clear that... Figure 3C As shown, an indentation 100b is also formed on the shoulder 11b, thus fixing the angle θ2 of the shoulder 11b.

[0078] Therefore, by fixing the angle θ1 of shoulder 11a and the angle θ2 of shoulder 11b, the spacing accuracy between the open ends 11m and 11n of the conductor straight portions 11g and 11h is improved, thereby obtaining the target spacing size.

[0079] In Example 1, as Figure 3B , Figure 3C , Figure 5C As shown, the indentations 100a and 100b are formed on the shoulders 11a and 11b on the outer side relative to the central part and on the inner side relative to the outer end (the side surrounded by the U-shaped section coil 11 is called the inner side, and the side outside is called the outer side), but the indentations 100a and 100b may also be formed across the outer end of the shoulders 11a and 11b.

[0080] Next, use Figures 6A to 9 The state of shoulder 11a is described. Figure 6A An enlarged view of the front of the section of coil before bending. Figure 6B for Figure 6A VIB-VIB line cross-section diagram in the middle, Figure 7A This is a magnified view of the front of the section of the coil before the indentation is formed after bending. Figure 7B for Figure 7A Sectional view along line VIIB-VIIB in the diagram. Figure 8A This is a magnified view of the front of the section of coil after the indentation has been formed. Figure 8B for Figure 8A Sectional view of line VIIIB-VIIIB in the middle. Figure 9 To Figure 6B , Figure 7B , Figure 8B A graph comparing the film thickness of the coil segments within the circuit. Furthermore, Figure 8A and Figure 8B In the middle, the indentation 100a is formed at the outer end of the cross and shoulder 11a.

[0081] Figure 6B , Figure 7B , Figure 8B In the middle, an enamel coating 7 is applied to the outer periphery of section coil 11. VIB-VIB wire pair Figure 6A The state of the cross section becomes Figure 6B . Figure 6B and Figure 9In the enamel coating 7 before bending, the coating thickness 7a is 61 μm, the coating thickness 7b is 61 μm, and the coating thickness 7c is 66 μm. In the dimensions of the segment coil 11 in Example 1, the thickness T in the bending direction is set to 3.6 mm, and the width W in the bending width direction is set to 2.6 mm.

[0082] When the section coil 11 is bent along its edge, the shape of the section coil 11 changes, becoming... Figure 7B It looks like that. Figure 7B It is the VIIB-VIIB line pair Figure 7A It is obtained by making a cross section.

[0083] Before the indentation 100a is formed after the bending process at shoulder 11a. Figure 7B In the enamel coating 6, the thickness of coating 7a is 61 μm, the thickness of coating 7b is 52 μm, and the thickness of coating 7c is 74 μm. Due to the bending along the edge, the thickness T' in the bending direction of the shoulder 11a decreases (T > T'), while the inner side of the bend in the bending width W' of the shoulder 11a becomes thicker (W < W'). The coating thickness 7b (52 μm) on the outer side of the bend is stretched during bending, so it is thinner than the coating thickness 7c (74 μm) on the inner side of the bend. The coating thickness 7b (52 μm) becomes the minimum thickness of the coating in the shoulder 11a.

[0084] Therefore, when forming the indentation 100a, it is necessary to avoid further thinning of the coating. The connecting portion between the formed portion and the non-formed portion of the indentation 100a is preferably a connection that prevents the coating from thinning. Figure 8B Set the radius of curvature R to 0.2 or higher as shown. Figure 8B It is the VIIIB-VIIIB line pair Figure 8A It is obtained by making a cross section. In addition, in Example 1, the depth of the indentation 100a is set to 0.3mm. The deviation of the distance between the open end 11m and the open end 11n varies according to the depth of the indentation 100a, that is, the amount of indentation of the punch, etc. Figure 10 A diagram showing the relationship between the spacing between the open ends 11m and 11n of the straight section of the conductor and the depth of the indentation 100a.

[0085] Figure 10 In the diagram, the vertical axis represents the distance between the open ends 11m and 11n of the straight portion of the conductor, and the horizontal axis represents the depth of the indentation 100a (punch indentation). The dashed line extending along the horizontal axis represents the target size of the distance between the open ends 11m and 11n. Preferably, the distance between the open ends 11m and 11n should reduce the deviation from this target size while also reducing the range (width) of the deviation. Figure 10 The diagram shows that when the width of the upper and lower limits decreases, the deviation in the spacing between the open ends 11m and 11n decreases.

[0086] Figure 10 Before the indentation 100a is formed, the deviation range of the distance between the open end 11m and the open end 11n is large. As the shoulder 11a is pressed down from this state to continuously deepen the indentation 100a, the deviation range of the distance between the open end 11m and the open end 11n continuously decreases. However, as the depth of the indentation 100a is continuously increased, the deviation range of the distance between the open end 11m and the open end 11n again continuously increases.

[0087] Based on this tendency, the depth of the indentation 100a is determined by minimizing the deviation range of the spacing between the open ends 11m and 11n, with the area near the center of this deviation range roughly matching the target size. Furthermore, when determining the depth of the indentation 100a, the thickness of the enamel coating 7 and the insulation breakdown voltage of the section coil 11 required for products using electric motors must be considered. Therefore, the depth of the indentation 100a is determined by minimizing the deviation range of the spacing between the open ends 11m and 11n, and based on the thickness of the enamel coating 7 and the insulation breakdown voltage of the section coil 11.

[0088] Furthermore, in Embodiment 1, indentations 100a are formed on both sides of the segment coil 11, but indentations 100a may also be formed only on one side of the segment coil 11. Also, in Embodiment 1, the radius of curvature R of the connecting portion is set to 0.2, but the radius of curvature of the connecting portion can be determined as appropriate based on the depth of the indentation 100a determined by the above conditions.

[0089] In Example 1, indentations 100a are formed by pressing the shoulders 11a and 11b, causing plastic deformation of the shoulders 11a and 11b. The angles θ1 of shoulder 11a and θ2 of shoulder 11b are fixed as target angles by the flow and work hardening of the metal previously present in the shoulders 11a and 11b. As a result, the distance between the open end 11m of the conductor straight portion 11g and the open end 11n of the conductor straight portion 11h becomes the target dimension.

[0090] According to Embodiment 1, the deviation in the spacing between the open end 11m of the conductor straight portion 11g and the open end 11n of the conductor straight portion 11h can be suppressed, thus improving the insertion performance of the segment coil 11.

[0091] Furthermore, according to Embodiment 1, the stacking thickness of the stator core 12 can be increased while improving the insertionability of the section coil 11, thus providing an electric motor with improved efficiency.

[0092] Furthermore, it can increase the proportion of the section coil 11 within the armature slot 12a, thus providing an electric motor with improved efficiency.

[0093] Example 2

[0094] use Figure 11A and Figure 11B Embodiment 2 of the present invention will be described below. Figure 11A and Figure 11B This is an enlarged view of the shoulder 11a of the section coil 11 related to Embodiment 2. The difference between Embodiment 2 and Embodiment 1 lies in the shape of the indentation.

[0095] Figure 11A In this case, an indentation 101a is formed from the outer end of the shoulder 11a toward the inner end. The indentation 101a does not reach the inner end of the shoulder 11a, and the inner side of the indentation 101a is formed in an arc shape. Based on this shape, the shape of the fixture used to form the indentation 101a can be simplified.

[0096] Figure 11B In the middle, an indentation 102a is formed within the area of ​​the shoulder 11a, the inclined portion 11e of the coil end conductor, and the straight portion 11g of the conductor, respectively, without reaching the outer end and the inner end. The indentation 102a is formed from the straight portion 11g of the conductor to the coil end vertex 11c of the section coil 11 ( Figure 3A It is formed by tilting it in a straight line relative to the straight section 11g of the conductor.

[0097] According to Example 2, in addition to the effects of Example 1, the types of clamps used to form indentations can be expanded.

[0098] Example 3

[0099] use Figure 12A and Figure 12B Embodiment 3 of the present invention will be described below. Figure 12A and Figure 12B This is an enlarged view of the shoulder 11a of the section coil 11 related to Embodiment 3. The difference between Embodiment 3 and Embodiment 1 lies in the angle of the edge bending process.

[0100] Compared with Example 1, in Example 3, the angle θ5 of 12A is in the relationship of θ3 < θ1 < θ5.

[0101] The target angle of the shoulder 11a in Example 3 is the same angle θ1 as in Example 1. During the bending process of the segment coil 11, springback occurs in the bent portion as it attempts to return to its original shape. Therefore, at the shoulder 11a, the amount of springback is considered... Figure 12B As shown, the shoulder 11a is bent to an angle θ5 (θ1 < θ5) that is larger than the target angle θ1. Then, the segment coil 11 is released from the molding die and fixture with the shoulder 11a at an angle of angle θ5.

[0102] Next, the segment coil 11 released from the molding die and fixture is installed into the indentation forming apparatus described later. The indentation forming apparatus is equipped with guide pins 40a to 40d for adjusting the angle of the shoulder 11a of the segment coil 11. Guide pins 40a and 40b are configured to clamp the inclined portion 11e of the coil end conductor, and guide pins 40c and 40d are configured to clamp the straight portion 11g of the conductor. With the inclined portion 11e of the coil end conductor and the straight portion 11g of the conductor clamped by guide pins 40a and 40b, and guide pins 40c and 40d respectively, the guide pins 40c and 40d are moved by decreasing the angle of the shoulder 11a, thereby moving the straight portion 11g of the conductor. Subsequently, guide pins 40c and 40d stop at an angle θ5' on shoulder 11a, and the angle of shoulder 11a is set as the target angle, i.e., angle θ1 (θ1 = θ5').

[0103] With the angle of shoulder 11a fixed at angle θ5' (θ1), an indentation 100a is formed on shoulder 11a. The indentation 100a is formed by pressing the surface of segment coil 11 with a punch or similar tool, causing the width W of segment coil 11 to become smaller than other parts. After forming indentations 100a and 100b, when segment coil 11 is released from the indentation forming device, the angle of shoulder 11a is fixed at angle θ5' (θ1). Furthermore, in Embodiment 3, indentation 100a is formed by dividing shoulder 11a by clamping it. Indentation 100b is formed in the same way.

[0104] According to Example 3, after performing edge bending processing to an angle θ5 larger than the target angle θ1, the angle θ5 is changed to the target angle θ1 (θ5'). Therefore, in addition to the effect of Example 1, the operation time until the target angle θ1 (θ5') is formed can be shortened.

[0105] Example 4

[0106] use Figure 13 Embodiment 4 of the present invention will be described below. Figure 13 This is an enlarged view of the shoulder 11a of the section coil 11 related to Example 4. The difference between Example 4 and Example 1 lies in the number of indentations formed and the location of the indentations.

[0107] Figure 13In the coil, an indentation 104a is formed on the inclined portion 11e of the coil end conductor connected to the shoulder 11a, and an indentation 105a is formed across the inclined portion 11e of the coil end conductor, the shoulder 11a, and the straight portion 11g of the conductor. The inclined portion 11e of the coil end conductor and the shoulder 11a form the curved portion of the segment coil 11, and the straight portion 11g of the conductor forms the straight portion of the segment coil 11. In other words, the indentation 104a is formed on the straight portion, and the indentation 105a is formed on a part of the curved portion and a part of the straight portion.

[0108] In Example 4, by pressing the inclined portion 11e of the coil end conductor and the portion spanning the inclined portion 11e, shoulder 11a, and straight portion 11g of the coil end conductor, the copper of the section coil 11 undergoes work hardening, and its shape bulges outward. Therefore, the second moment of the cross section at shoulder 11a increases, and the bending stiffness is improved. Furthermore, although not shown, the shoulder 11b, the inclined portion 11f of the coil end conductor, and the straight portion 11h of the conductor are also the same.

[0109] When a section coil 11 is inserted into the armature slot 12a, the coil end vertex 11c and the coil end conductor sloping portions 11e and 11f are pushed, thereby deforming the coil end conductor sloping portions 11e and 11f due to the insertion load. In embodiment 4, since an indentation 104a is formed on the coil end conductor sloping portions 11e and 11f, the amount of deformation at the coil end conductor sloping portions 11e and 11f can be suppressed, thereby improving the insertion of the section coil 11 into the armature slot 12a.

[0110] Example 5

[0111] Use Figure 14 to Figure 15 Embodiment 5 of the present invention will be described below. Figure 14A and Figure 14B This is a cross-sectional view of the main part of the indentation forming device 200. Figure 15 This is a flowchart illustrating the indentation forming process performed by the indentation forming apparatus 200.

[0112] The indentation forming apparatus 200 includes an upper punch 201, a pressing plate 202, an upper workpiece pressure plate 203, a lower punch 204, a seat plate 205, a lower workpiece pressure plate 206, and guide pins 40a to 40d (not shown) (for reference). Figure 5C , Figure 12B , Figure 13The upper punch 201 forms an indentation on one side of the segment coil 11. The pressing plate 202 has the upper punch 201 and applies pressing force to the upper punch. The upper workpiece pressure plate 203 has a guide hole 203a (upper guide hole) for guiding the movement of the upper punch 201. The lower punch 204 forms an indentation on the other side of the segment coil 11. The base plate 205 has the lower punch 204 and applies pressing force to the lower punch. The lower workpiece pressure plate 206 has a guide hole 204a (lower guide hole) for guiding the movement of the lower punch 204. Furthermore, although not shown, a spring is provided between the pressing plate 202 and the upper workpiece pressure plate 203, and a predetermined gap is formed between the pressing plate 202 and the upper workpiece pressure plate 203 by means of the spring force. Similarly, a spring is provided between the seat plate 205 and the lower workpiece pressure plate 206, and a specified gap is formed between the seat plate 205 and the lower workpiece pressure plate 206 by means of the spring force.

[0113] The central part of the lower workpiece pressure plate 206 is convex to the upper workpiece pressure plate 203, and the central part of the upper workpiece pressure plate 203 is concave to receive the convex shape of the lower workpiece pressure plate 206.

[0114] The indentation forming device 200 operates in the following manner.

[0115] like Figure 14A As shown, a U-shaped section coil 11 that has undergone edge bending is placed in the center of the lower workpiece pressure plate 206 (step S301: process of placing the U-shaped section coil on the lower workpiece pressure plate).

[0116] Next, the load generating device (not shown) is activated, causing the upper workpiece pressure plate 203 to move towards the lower workpiece pressure plate 206. The upper workpiece pressure plate 203 and the lower workpiece pressure plate 206 clamp and fix the segment coil 11 (step S302: the process of fixing the segment coil 11 by moving the upper workpiece pressure plate towards the lower workpiece pressure plate). The lower workpiece pressure plate 206 bears the weight of the pressing plate 202 and the upper workpiece pressure plate 203 in addition to the load generated by the load generating device, so it moves towards the base plate 205. The movement of the lower workpiece pressure plate 206 causes the lower punch 204 to move within the guide hole 204a, with the top end of the lower punch 204 facing the other side of the segment coil 11.

[0117] Next, the guide pins 40a to 40d are actuated to adjust the angle of the shoulders 11a and 11b of the segment coil 11 to the target angle θ1 (step S303: the process of actuating the guide pins to adjust the angle of the shoulders of the segment coil to the target angle).

[0118] Next, the load generating device is activated to further apply a load to the pressing plate 202, which overcomes the force of the spring and presses against the upper workpiece pressure plate 203. The pressing of the pressing plate 202 causes the upper punch connected to the pressing plate 202 to move within the guide hole 203a. The upper punch protrudes from the guide hole 203a and presses one side of the shoulder portions 11a and 11b of the segment coil 11, forming indentations 100a and 100b. When the pressing force of the pressing plate 202 is further applied, the lower punch 204 protrudes from the guide hole 204a and presses the other side of the shoulder portions 11a and 11b of the segment coil 11, forming indentations 100a and 100b (step S304: the process of applying a load to the pressing plate 202 to form indentations 100a and 100b on the shoulder portions 11a and 11b of the segment coil 11). As mentioned above, when the depth of the indentation increases, the deviation in the spacing between the open ends increases, so the load generating device operates in a way that adjusts the load applied to the pressing plate 202.

[0119] After the indentations 100a and 100b are formed, the load on the pressing plate 202 by the load generating device is released (step S305: process of releasing the load on the pressing plate 202). When the load on the pressing plate 202 is released, the force of the spring disposed between the pressing plate 202 and the upper workpiece pressure plate 203 causes the pressing plate 202 to separate from the upper workpiece pressure plate 203. Similarly, the force of the spring disposed between the seat plate 205 and the lower workpiece pressure plate 206 causes the seat plate 205 to separate from the lower workpiece pressure plate 206.

[0120] Next, the upper workpiece pressure plate is lifted away from the lower workpiece pressure plate 206 (step S306: the process of lifting the upper workpiece pressure plate away from the lower workpiece pressure plate 206).

[0121] Next, the section coil 11, whose angles of shoulder 11a and 11b have been fixed at angles θ1 and θ2 respectively, is removed from the indentation forming device (step S307: process of removing section coil 11 from indentation forming device).

[0122] Collect multiple segmented coils 11 taken from the indentation forming device, like Figure 1 Insert it into the armature slot 12a of the stator core 12 as shown (step S308: the process of inserting the section coil 11 into the armature slot 12a of the stator core 12).

[0123] The stator of the electric motor is manufactured in the manner described above.

[0124] According to Embodiment 5, a stator manufacturing method for an electric motor can be provided to suppress angular deviations at the shoulder of the segment coil and improve the insertion of the segment coil into the stator core.

[0125] Furthermore, the present invention includes various modifications and is not limited to the above embodiments.

[0126] The above embodiments are provided to illustrate the invention in an easily understandable manner and are not necessarily limited to having all the described configurations.

[0127] Symbol Explanation

[0128] 10…Stator, 11…Section coil, 11a…Shoulder (first curved section), 11b…Shoulder (second curved section), 11c…Coil end vertex, 11d…Coil end bend, 11e, 11f…Coil end conductor oblique section, 11g, 11h…Conductor straight section, 11m, 11n…Open end, 12…Stator core, 12a…Armature slot, 12b…Side, 13…Insulating paper, 14…Gap, 100a, 100b, 101a, 102a, 104a, 105a…Indentation, 200…Indentation forming device, 201…Upper punch, 202…Pressing plate, 203…Upper workpiece pressing plate, 203a…Guide hole, 204…Lower punch, 204a…Guide hole, 205…Seat plate, 206…Lower workpiece pressing plate.

Claims

1. A stator for an electric motor, comprising a stator core having a plurality of armature slots and a plurality of U-shaped coil segments inserted into the plurality of armature slots, characterized in that, The segment coil has a first curved portion and a second curved portion that are bent to form a U-shape. When viewed from the front in a U-shaped configuration, indentations are formed on the first curved portion and the second curved portion, extending in a front-to-back direction from one side of the first curved portion and the other side of the second curved portion.

2. The stator of the electric motor according to claim 1, characterized in that, The section coil is made of a flat conductor, and the first curved section and the second curved section are formed by bending the flat conductor along its edges.

3. The stator of the electric motor according to claim 1 or 2, characterized in that, The indentation is formed on the opposite side to one side of the first curved portion and one side of the second curved portion.

4. The stator of the electric motor according to claim 1 or 2, characterized in that, The radius of curvature R of the connecting portion between the formed part and the non-formed part of the indentation is set to 0.2 or more.

5. The stator of the electric motor according to claim 1 or 2, characterized in that, The indentation is formed on the outer side relative to the central portion of the first and second curved portions.

6. The stator of the electric motor according to claim 5, characterized in that, The indentation is formed on the inner side relative to the outer ends of the first and second curved portions.

7. The stator of the electric motor according to claim 5, characterized in that, The indentation is formed across the outer ends of the first curved portion and the second curved portion.

8. The stator of the electric motor according to claim 1 or 2, characterized in that, The indentation is formed from the outer ends of the first curved portion and the second curved portion toward the inner side, and the inner side of the indentation is formed into an arc shape.

9. The stator of the electric motor according to claim 1 or 2, characterized in that, The segment coil has a curved portion and a straight portion, the curved portion having a first curved portion and a second curved portion, and the straight portion being connected to the curved portion. The indentation is formed at a straight angle relative to the straight portion.

10. The stator of the electric motor according to claim 1 or 2, characterized in that, The segment coil has a curved portion and a straight portion, the curved portion having a first curved portion and a second curved portion, and the straight portion being connected to the curved portion. An indentation is formed on a portion of the straight section.

11. The stator of the electric motor according to claim 10, characterized in that, The curved portion includes a coil end conductor oblique portion connected to the first curved portion and the second curved portion. An indentation is formed on the oblique portion of the conductor at the end of the coil.

12. A method for manufacturing the stator of an electric motor, wherein multiple segmented coils formed in a U-shape are inserted into multiple armature slots formed on a stator core, characterized in that... The segment coil has a first curved portion and a second curved portion that are bent to form a U-shape. When viewed from the front in a U-shaped configuration, indentations are formed on the first curved portion and the second curved portion, extending in a front-to-back direction from one side of the first curved portion, one side of the second curved portion, and the other side opposite to one side of the first curved portion and the second curved portion. The indentation is formed by an indentation forming device. The indentation forming apparatus comprises: an upper punch that forms an indentation on one side of the segment coil; a pressing plate having the upper punch and applying pressing force to the upper punch; an upper workpiece plate having an upper guide hole for guiding the movement of the upper punch; a lower punch that forms an indentation on the other side of the segment coil; a base plate having the lower punch and applying pressing force to the lower punch; a lower workpiece plate having a lower guide hole for guiding the movement of the lower punch; and a guide pin for adjusting the angles of the first curved portion and the second curved portion of the segment coil. The indentation forming apparatus includes the following steps: The section coil is placed on the lower workpiece pressure plate; The upper workpiece pressure plate is moved toward the lower workpiece pressure plate to fix the section coil; The guide pin is actuated to adjust the angles of the first curved portion and the second curved portion of the segment coil to the target angle; A load is applied to the pressure plate to form the indentation in the first curved portion and the second curved portion of the section coil; Release the load on the pressure plate; and The upper workpiece pressure plate is moved away from the lower workpiece pressure plate.

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