Stator coil

Abstract

This invention provides technology for appropriately designing connecting members that link the conductors of a coil. [Solution] The stator coil comprises a first conductor that constitutes a part of the stator coil, a second conductor that constitutes another part of the stator coil, and a connecting member that connects the tip of the first conductor and the tip of the second conductor. The connecting member is a hollow tube having a first end into which the first conductor is press-fitted and a second end into which the tip of the second conductor is press-fitted, and the wall thickness of the hollow tube is 0.2 mm to 0.5 mm.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a stator coil.

Background Art

[0002] A stator coil is disclosed in Patent Document 1. The stator coil of Patent Document 1 includes a first conductor constituting a part of the stator coil, a second conductor constituting another part of the stator coil, and a connecting member that connects the tip of the first conductor and the tip of the second conductor. The connecting member has a cylindrical shape, and the tip of the first conductor and the tip of the second conductor are press-fitted from both ends thereof.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the stator coil as described above, the thicker the connecting member is, the thinner the tip of each conductor needs to be. In this case, when connecting the two by press-fitting, the tip of each conductor is highly likely to buckle. Conversely, the thicker the tip of each conductor is, the thinner the connecting member needs to be. In this case, when connecting the two by press-fitting, the connecting member is highly likely to buckle. Therefore, regarding the thickness of the connecting member, it is necessary to design its dimensions so as to avoid buckling of the tip of each conductor and buckling of the connecting member.

[0005] In addition, from the perspective of electrical resistance, increasing the wall thickness of the connecting member increases the cross-sectional area of ​​the connecting member, thus reducing electrical resistance. On the other hand, if the wall thickness of the connecting member is made too large, the ends of each conductor become too thin, which can actually increase electrical resistance. Furthermore, from the perspective of manufacturing the connecting member, if the wall thickness is made too large, for example, when manufacturing the connecting member by deep drawing, insufficient contact with the mold can occur, leading to a decrease in dimensional accuracy. Therefore, these points must also be considered when designing the wall thickness of the connecting member.

[0006] In view of the above, this specification provides techniques for appropriately designing connecting members. [Means for solving the problem]

[0007] A first aspect of this technology is embodied in a stator coil. The stator coil comprises a first conductor constituting a part of the stator coil, a second conductor constituting another part of the stator coil, and a connecting member connecting the tip of the first conductor and the tip of the second conductor. The connecting member is a hollow tube having a first end into which the first conductor is press-fitted and a second end into which the tip of the second conductor is press-fitted, and the wall thickness of the hollow tube is 0.2 mm to 0.5 mm.

[0008] In the above configuration, the connecting member is a hollow tube with a wall thickness of 0.2 mm to 0.5 mm. With this configuration, when the ends of the first conductor and the second conductor are connected via the connecting member, buckling of the ends of each conductor and the connecting member can be avoided. In addition, if the wall thickness of the connecting member is within the above numerical range, the electrical resistance of the connection part due to the connecting member will not increase excessively, and the manufacturing of the connecting member will not become particularly difficult. [Brief explanation of the drawing]

[0009] [Figure 1] Exploded perspective view of the stator in the embodiment. [Figure 2]Front view of the first segment, second segment, and connecting member of the stator coil in the embodiment. [Figure 3] A graph showing the relationship between the wall thickness and surface pressure of the connecting member. [Modes for carrying out the invention]

[0010] The stator coil 4 of the embodiment will be described with reference to the drawings. Figure 1 shows a stator 2 employing the stator coil 4 of the embodiment. As shown in Figure 1, the stator 2 comprises a stator core 6 and a stator coil 4. The stator coil 4 comprises a plurality of first segments 10, a plurality of second segments 30, and a plurality of connecting members 50. Note that the actual stator coil 4 comprises a large number of first segments 10, a large number of second segments 30, and a large number of connecting members 50, but for the sake of clarity, Figure 1 shows only a small portion of the first segments 10, a small portion of the second segments 30, and a small portion of the connecting members 50.

[0011] The stator 2 of the embodiment, when combined with a rotor, constitutes a rotating electric machine (not shown). The rotating electric machine to which the stator 2 is applied may be used, for example, as an electric motor or as a generator. The stator 2 of the embodiment is used, for example, in a rotating electric machine mounted on an electric vehicle. This rotating electric machine functions, for example, as an electric motor that generates power for the electric vehicle to run, and as a generator that generates electricity using the regenerative torque of the electric vehicle.

[0012] The stator core 6 constituting the stator 2 of the embodiment comprises an annular core back 80 and a plurality of teeth 82 projecting radially inward from the inner circumferential surface of the core back 80. Between adjacent teeth 82 in the circumferential direction of the stator core 6, slots 84 are formed, which are spaces for accommodating a portion of the stator coil 4. The stator core 6 may be constructed, for example, by laminating a plurality of electromagnetic steel sheets. Alternatively, the stator core 6 may be constructed, for example, by press-forming a particulate or powdered magnetic material.

[0013] The stator coils 4 that constitute the stator 2 in this embodiment are wound around the teeth 82 of the stator core 6. The connection and winding configuration of the stator coils 4 are appropriately selected according to the specifications of the rotating electric machine. For example, the stator coils 4 for the U-phase, V-phase, and W-phase are connected in a star connection or a delta connection. The stator coils 4 may also be wound in a distributed winding or a concentrated winding.

[0014] The stator coil 4 is divided into multiple first segments 10 and multiple second segments 30 for ease of manufacturing. The multiple first segments 10 and multiple second segments 30 are connected within the slots 84 of the stator core 6 by multiple connecting members 50. This completes the manufacturing of the stator coil 4.

[0015] The shape of each first segment 10 is appropriately set according to the shape of the stator coil 4. The shape of the first segment 10 is, for example, partially bent or curved. Alternatively, the shape of the first segment 10 is, for example, partially straight or curved. The shape of the second segment 30 is the same as that of the first segment 10.

[0016] As shown in Figure 2, the first segment 10 of the stator coil 4 comprises a first conductor 12 and a first coating 14 covering the first conductor 12. The first conductor 12 of the first segment 10 is made of a conductive material such as copper. The cross-sectional shape of the first conductor 12 perpendicular to the axial direction is rectangular. The first coating 14 is made of an insulating material such as resin.

[0017] The first conductor 12 comprises a main body 20 and a pair of tip portions 22. The main body 20 of the first conductor 12 is covered with a first coating 14. The tip portions 22 of the first conductor 12 are not covered with the first coating 14. The tip portions 22 of the first conductor 12 are exposed from the first coating 14. The tips of the tip portions 22 of the first conductor 12 have, for example, a tapered shape.

[0018] Next, the second segment 30 of the stator coil 4 will be described. The second segment 30 has the same configuration as the first segment 10 described above. That is, as shown in FIG. 2, the second segment 30 includes a second conductor 32 and a second coating 34 that covers the second conductor 32. The second conductor 32 of the second segment 30 is made of a conductive material such as copper. The cross-sectional shape perpendicular to the axial direction of the second conductor 32 is rectangular. The second coating 34 is made of an insulating material such as resin.

[0019] The second conductor 32 includes a main body portion 40 and a pair of tip portions 42. The main body portion 40 of the second conductor 32 is covered by the second coating 34. The tip portions 42 of the second conductor 32 are not covered by the second coating 34. The tip portions 42 of the second conductor 32 are exposed from the second coating 34. The tips of the tip portions 42 of the second conductor 32 are, for example, tapered in a tapered shape.

[0020] Next, the connecting member 50 that connects the first segment 10 and the second segment 30 will be described. The connecting member 50 is made of a conductive material such as copper. The connecting member 50 is a hollow tube. Although it is an example, the connecting member 50 in the present embodiment is a rectangular tube and is a cylindrical member having a rectangular cross-sectional shape perpendicular to the axial direction. The symbol t in FIG. 2 represents the wall thickness of the side portion of the rectangular tube of the connecting member 50.

[0021] The connecting member 50 includes a first end portion 60 and a second end portion 62. The first end portion 60 is located at one end in the axial direction of the connecting member 50, and the second end portion 62 is located at the other end in the axial direction of the connecting member 50. The first end portion 60 is open at one end in the axial direction of the connecting member 50, and the second end portion 62 is open at the other end in the axial direction of the connecting member 50.

[0022] At the first end portion 60 of the connecting member 50, the tip portion 22 of the first conducting wire 12 of the first segment 10 is press-fitted. When the tip portion 22 of the first conducting wire 12 is press-fitted into the first end portion 60 of the connecting member 50, the outer peripheral surface of the tip portion 22 of the first conducting wire 12 and the inner peripheral surface of the first end portion 60 adhere to each other. Thereby, the connecting member 50 and the tip portion 22 of the first conducting wire 12 are physically and electrically connected.

[0023] Similarly, at the second end portion 62 of the connecting member 50, the tip portion 42 of the second conducting wire 32 of the second segment 30 is press-fitted. When the tip portion 42 of the second conducting wire 32 is press-fitted into the second end portion 62 of the connecting member 50, the outer peripheral surface of the tip portion 42 of the second conducting wire 32 and the inner peripheral surface of the second end portion 62 adhere to each other. Thereby, the connecting member 50 and the tip portion 42 of the second conducting wire 32 are physically and electrically connected.

[0024] Next, referring to FIG. 3, the wall thickness t of the connecting member 50 will be described. Also in the stator coil 4 of the present embodiment, regarding the wall thickness t of the connecting member 50, it is necessary to design its dimensions so that the tip portions 22 and 42 of the respective conducting wires 12 and 32 do not buckle and the connecting member 50 does not buckle. In this regard, FIG. 3 is a graph showing the relationship between the wall thickness t of the connecting member 50 and the surface pressure. In FIG. 3, the group of plotted points a represents the surface pressure applied to the tip portions 22 and 42 of the respective conducting wires 12 and 32, and the group of plotted points b represents the surface pressure applied to the connecting member 50. As shown by the group of plotted points a, as the wall thickness t of the connecting member 50 increases, the surface pressure applied to the tip portions 22 and 42 of the respective conducting wires 12 and 32 increases. On the other hand, as shown by the group of plotted points b, as the wall thickness t of the connecting member 50 increases, the surface pressure applied to the connecting member 50 increases. Thus, the surface pressure applied to the connecting member 50 and the surface pressure applied to the tip portions 22 and 42 of the respective conducting wires 12 and 32 are in an inverse correlation relationship with each other.

[0025] Assuming that the length of each side of the rectangular tube of the connecting member 50 is constant, if the wall thickness t of the connecting member 50 increases, it becomes necessary to thin the tips 22 and 42 of each conductor 12 and 32. Thinning the tips 22 and 42 of each conductor 12 and 32 reduces the cross-sectional area of ​​the tips 22 and 42, so the surface pressure applied to the tips 22 and 42 of each conductor 12 and 32 increases during press-fitting. When this surface pressure exceeds a certain value x1, the tips 22 and 42 of each conductor 12 and 32 buckle. In the configuration of this embodiment, the value of x1 is approximately HV80.

[0026] Conversely, assuming that the length of each side of the rectangular tube of the connecting member 50 is constant, if the wall thickness t of the connecting member 50 becomes thinner, the cross-sectional area of ​​the connecting member 50 decreases, and therefore the surface pressure applied to the connecting member 50 during press-fitting increases. When the surface pressure applied to the connecting member 50 exceeds a certain value x2, the connecting member 50 buckles. In the configuration of this embodiment, the value of x2 is approximately HV115.

[0027] When the wall thickness t of the connecting member 50 is slightly less than 0.2 mm, the surface pressure during crimping is x1. When the wall thickness t of the connecting member 50 is slightly greater than 0.5 mm, the surface pressure during crimping is x2. Therefore, the wall thickness t of the connecting member 50 should be designed to be between 0.2 mm and 0.5 mm in order to avoid buckling of the ends 22 and 42 of each conductor 12 and 32, as well as buckling of the connecting member 50.

[0028] The configuration of the embodiment has been described above. As is clear from the above description, the stator coil 4 of the embodiment is characterized in that the wall thickness t of the side portion of the rectangular tube of the connecting member 50 is 0.2 mm to 0.5 mm.

[0029] With this configuration, the wall thickness t of the rectangular tube side of the connecting member 50 is 0.2 mm to 0.5 mm, which prevents buckling of the tip 22 of the first conductor 12 and the connecting member 50 when the tip 22 of the first conductor 12 is press-fitted into the first end 60 of the connecting member 50. Similarly, when the tip 42 of the second conductor 32 is press-fitted into the second end 62 of the connecting member 50, it is possible to prevent buckling of the tip 42 of the second conductor 32 and the connecting member 50. In addition, if the wall thickness t of the connecting member 50 is within the above numerical range, the electrical resistance of the connection portion by the connecting member 50 will not increase excessively, and the manufacturing of the connecting member 50 will not become particularly difficult. Note that the connecting member 50 is not limited to a rectangular tube, but may be a hollow tube with any cross-sectional shape. In this case as well, if its wall thickness t is 0.2 mm to 0.5 mm, the same effect as described above can be expected. [Explanation of Symbols]

[0030] 2: Stator, 4: Stator coil, 6: Stator core, 10: First segment, 12: First conductor, 14: First coating, 20: Main body, 22: Tip, 30: Second segment, 32: Second conductor, 34: Second coating, 40: Main body, 42: Tip, 50: Connecting member, 60: First end, 62: Second end, 80: Core back, 82: Teeth, 84: Slot

Claims

[Claim 1] It is a stator coil, It comprises a first conductor that constitutes a part of the stator coil, a second conductor that constitutes another part of the stator coil, and a connecting member that connects the tip of the first conductor and the tip of the second conductor, The stator coil is characterized in that the connecting member is a hollow tube having a first end into which the first conductor is press-fitted and a second end into which the tip of the second conductor is press-fitted, and the wall thickness of the hollow tube is 0.2 mm to 0.5 mm.

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