Rotating Electric Machine

Abstract

To provide a rotary electric machine capable of improving the conduction reliability of a connection portion of two rectangular wire-shaped segment coils in a slot of a stator core without increasing production man-hours.SOLUTION: A rotary electric machine includes a stator coil 8 that has a first rectangular wire 81 having a protrusion 8a at one end, a second rectangular wire 82 having a groove 8b at one end, and a fitting portion 8c in which the protrusion 8a is fitted into the groove 8b. Both shapes of cross sections 8aa and 8ba of the protrusion 8a and the groove 8b are rectangular. The rectangle has first sides 8a1 and 8b1, second sides 8a2 and 8b2 opposite to the first sides 8a1 and 8b1 and longer than the first sides 8a1 and 8b1, and third sides 8a3 and 8b3 and fourth sides 8a4 and 8b4 that connect the first sides 8a1 and 8b1 and the second sides 8a2 and 8b2, respectively, and face each other. In the fitting portion 8c, the protrusion 8a is fitted into the groove 8b so that the first side 8a1 and the second side 8a2 in the protrusion 8a correspond to the first side 8b1 and the second side 8b2 in the groove 8b.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] While there is a demand for miniaturization of rotating electrical machines, there is also a demand for improved electrical insulation. In particular, to miniaturize the stator, a structure that increases the winding space factor and achieves high power density is effective. Specifically, a stator structure consisting of segment coils using rectangular wire with a flat cross section, as opposed to the typical round wire used as a conductor, is effective. Methods for connecting segment coils when constructing a stator using rectangular wire can be broadly divided into coil end connection method and in-slot connection method.

[0003] In the coil end connection method, the segment coil is roughly U-shaped and has a pair of straight sections and an inclined section connecting them, and each of the two straight sections is housed in a slot in the stator core. The inclined sections protrude from the end in the axial direction of the stator core. Each straight section protrudes from the slot and is bent at the end on the opposite side in the axial direction of the stator core, and is welded at the coil end to the bent part of the straight section of another segment coil, resulting in a continuous connection.

[0004] In the in-slot connection method, the segment coil is roughly U-shaped, has a pair of straight parts and an inclined part connecting them, and the two straight parts are each stored in the slot of the stator core. The inclined parts are structured to protrude from the ends in the axial direction of the stator core. The configuration up to this point is almost the same as the coil end connection method. However, in the in-slot connection method, the straight parts of the two segment coils are inserted into the slot from both ends in the axial direction of the stator core and connected within the slot. In particular, this connection method is advantageous for high productivity and miniaturization compared to the coil end connection method, since it allows for the mass production and use of roughly U-shaped segment coils and does not require bending and welding at the coil end to connect the straight parts. Note that the shape of the ends of the straight parts connected within the slot may differ depending on the connection method used to connect the ends of the straight parts.

[0005] Patent Document 1 discloses a technique relating to a stator for a rotating electrical machine using such an in-slot connection method. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-023771 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the stator of the rotating electric machine of Patent Document 1, a concave portion and a convex portion are formed on the tip surfaces (ends of the straight portions) of the legs of two conductor segments (segment coils) facing each other within a slot, and the segments are joined in an engaged state by the concave-convex engagement portion formed by the concave-convex engagement portion.

[0008] However, since the convex portion in Patent Document 1 is roughly a quadrangular pyramid and the opposing concave portion is a space roughly equivalent in shape to the quadrangular pyramid, sufficient joint strength cannot be obtained by simply butting the concave portion with the convex portion, and electrical reliability cannot be ensured. In order to supplement the joint strength, it is also disclosed that a paste-like binder containing conductive particles is applied in advance to the tips (ends of the straight portions) of the legs of the conductor segments (segment coils), and the opposing legs are brought into contact with each other in each slot and pressurized and heated to harden the binder and join them, but this increases the number of production steps.

[0009] An object of the present invention is to provide a rotating electric machine capable of improving the reliability of conductivity at the connection portion of two rectangular wire-shaped segment coils within a slot of a stator core without increasing the number of production steps. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a stator coil having a first rectangular wire having a protrusion at one end, a second rectangular wire having a groove at one end, and a fitting portion in which the protrusion is fitted into the groove, wherein the cross-sectional shapes of the protrusion and the groove are both rectangular, and the rectangle has a first side, a second side facing the first side and longer than the first side, and a third side and a fourth side connecting the first side and the second side, respectively, and facing each other, and in the fitting portion: A first side of the protrusion corresponds to a second side of the groove, and a second side of the protrusion corresponds to a first side of the groove. The protrusion is fitted into the groove. Effect of the Invention

[0011] According to the present invention, it is possible to improve the reliability of electrical continuity at the connection of two rectangular wire segment coils in a slot of a stator core without increasing the number of steps required for the production of a rotating electric machine. Other problems, configurations, and effects will be made clear from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view showing a part of a cross section of a rotating electric machine according to a first embodiment of the present invention; [Diagram 2]1 is a schematic perspective view of a stator according to a first embodiment of the present invention; [Diagram 3] FIG. 1 is a schematic perspective view of a first rectangular wire and a second rectangular wire constituting a stator coil according to a first embodiment of the present invention before being inserted into any of a plurality of slots of a stator core. [Figure 4] FIG. 2 is a perspective view showing a protrusion portion at one end of a first rectangular wire according to a first embodiment of the present invention. [Diagram 5] FIG. 2 is a perspective view showing a groove portion at one end of the second rectangular wire according to the first embodiment of the present invention. [Figure 6] 2 is a perspective view showing a fitting portion of the stator coil according to the first embodiment of the present invention; FIG. [Figure 7] 4 is a perspective view showing corresponding sides when a protrusion and a groove are fitted together in the fitting portion according to the first embodiment of the present invention. FIG. [Figure 8] 13 is a perspective view showing corresponding sides when a protrusion and a groove are fitted together in a fitting portion according to a second embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a rotating electric machine 1 according to a first and second embodiment of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same parts. In each drawing, directions are specified by mutually orthogonal XYZ axes, with +X being "right", -X being "left", +Y being "up", -Y being "down", +Z being "front", and -Z being "rear".

[0014] (First embodiment) 1 is a perspective view showing a cross section of a part of a rotating electric machine 1 according to a first embodiment. The rotating electric machine 1 is an internal rotation type radial gap type rotating electric machine, and includes a stator 2 that generates magnetic force using electric power, a rotor 3 that rotates by the magnetic force generated by the stator 2, a shaft 4 that rotates together with the rotor 3, and a housing 5 that covers and protects the stator 2 and the rotor 3.

[0015] 2 is a schematic perspective view of the stator 2 according to this embodiment. The stator 2 includes a stator core 7 having a plurality of slots 6, and a plurality of stator coils 8 inserted into the respective slots 6 and wound in a distributed manner.

[0016] 3 is a schematic perspective view of the first and second rectangular wires 81 and 82 constituting the stator coil 8 according to this embodiment before being inserted into any of the slots 6 of the stator core 7. The stator coil 8 includes the first rectangular wire 81 having a protrusion 8a at at least one end (both ends in this embodiment) and the second rectangular wire 82 having a groove 8b at at least one end (both ends in this embodiment). The first rectangular wire 81 and the second rectangular wire 82 are electrically connected and physically joined at a fitting portion 8c (see FIG. 6) where the protrusion 8a fits into the groove 8b.

[0017] The first flat wire 81 is a conductor having a rectangular cross section that is flatter than a round wire, and is a segment coil formed into a roughly U-shape. The second flat wire 82 is a conductor having a rectangular cross section that is flatter than the first flat wire 81, and is a segment coil formed into a roughly U-shape.

[0018] FIG. 4 is a perspective view showing a protrusion 8a provided at one end of the first rectangular wire 81 according to this embodiment. The protrusion 8a is a prismatic protrusion protruding from the end face 81a of the first rectangular wire 81 along the axial direction (+Z direction) of the first rectangular wire 81. The protrusion 8a according to this embodiment protrudes from the rectangular end face 81a. Note that FIG. 4 shows an embodiment in which one protrusion 8a protrudes from approximately the center of the end face 81a in the X-axis direction, but is not limited to this. For example, it may protrude from a position shifted from the center of the end face 81a in the X-axis direction. Also, multiple protrusions 8a may protrude from the end face 81a.

[0019] The cross section 8aa of the protrusion 8a is rectangular, and has a first side 8a1, a second side 8a2 that faces the first side 8a1 and is longer than the first side 8a1, and a third side 8a3 and a fourth side 8a4 that connect the first side 8a1 and the second side 8a2 and face each other. In this embodiment, the cross section 8aa is trapezoidal, and the first side 8a1 and the second side 8a2 are parallel to each other. The third side 8a3 and the fourth side 8a4 are inclined inversely to the Y axis, and the angle is, for example, 0.5° to 1°. The shape of the cross section 8aa of the protrusion 8a can be made the same along the length direction (Z-axis direction) of the protrusion 8a, and in this case, a rectangular surface (end surface) having the same shape as the cross section 8aa appears at the tip of the protrusion 8a.

[0020] FIG. 5 is a perspective view showing a groove 8b provided at one end of the second rectangular wire 82 according to this embodiment. The groove 8b is a groove formed by recessing the end face 82a of the second rectangular wire 82 toward the axial direction of the second rectangular wire 82, and has openings on two side faces (the first side face 821 and the second side face 822) that face each other in the thickness direction (the vertical direction in FIG. 5) of the second rectangular wire 82. The groove 8b according to this embodiment is provided on the rectangular end face 82a. Note that FIG. 6 shows an embodiment in which one groove 8b is provided at approximately the center of the end face 82a in the X-axis direction, but is not limited to this. For example, it may be provided at a position shifted from the center of the end face 82a in the X-axis direction. In addition, multiple grooves 8b may be provided on the end face 82a.

[0021] The cross section 8ba of the groove 8b is rectangular, and has a first side 8b1, a second side 8b2 longer than the first side 8b1, and a third side 8b3 and a fourth side 8b4 that connect the first side 8b1 and the second side 8b2, respectively, and face each other. In this embodiment, the cross section 8ba is trapezoidal, and the first side 8b1 and the second side 8b2 are parallel to each other. The third side 8b3 and the fourth side 8b4 are inclined inversely to the Y axis, and the angle is, for example, 0.5° to 1°. The shape of the cross section 8ba of the groove 8b can be made the same along the depth direction (Z-axis direction) of the groove 8b, and in this case, a rectangular surface having the same shape as the cross section 8ba appears on the bottom surface of the groove 8b.

[0022] 6 is a perspective view showing a fitting portion 8c of the stator coil 8 according to this embodiment. The fitting portion 8c is a portion where the protrusion 8a fits into the groove 8b. In the fitting portion 8c, the protrusion 8a fits into the groove 8b such that a first side 8a1 and a second side 8a2 in a cross section 8aa of the protrusion 8a correspond to a first side 8b1 and a second side 8b2 in a cross section 8ba of the groove 8b.

[0023] 7 is a perspective view showing the corresponding sides of the fitting portion 8c according to this embodiment when the protrusion 8a and the groove 8b are fitted together. In the fitting portion 8c, the protrusion 8a is fitted into the groove 8b so that the first side 8a1 of the protrusion 8a corresponds to the first side 8b1 of the groove 8b, and the second side 8a2 of the protrusion 8a corresponds to the second side 8b2 of the groove 8b. It is preferable that the cross section 8aa of the protrusion 8a and the cross section 8ba of the groove 8b have the same shape. However, in this document, "same" does not limit the perfect agreement of the shapes, but allows for a range of error due to manufacturing tolerances and design tolerances.

[0024] One end of each of the first flat wire 81 and the second flat wire 82 shown in Fig. 3 is inserted from above and below (+Y direction and -Y direction) into a predetermined slot 6 of the stator core 7. Then, in the predetermined slot 6, the protrusion 8a is fitted into the groove 8b so that the first side 8a1 corresponds to the first side 8b1, and the second side 8a2 corresponds to the second side 8b2. As a result, the first flat wire 81 and the second flat wire 82 are electrically connected and physically joined.

[0025] The protrusion 8a may be fitted in the groove 8b in a tight fit state so that it does not easily come out of the groove 8b after being pressed into the groove 8b. In this case, the dimension of the protrusion 8a and the groove 8b fitting together (so-called fit tolerance) falls within the range of the interference fit tolerance. Specifically, the first side 8a1 of the protrusion 8a is longer than the first side 8b1 of the groove 8b within the range of the interference fit tolerance. Similarly, the second side 8a2 of the protrusion 8a is longer than the second side 8b2 of the groove 8b within the range of the interference fit tolerance.

[0026] [effect] In the rotating motor 1 of this embodiment, a protrusion 8a provided at the end of a first rectangular wire 81 and a groove 8b provided at the end of a second rectangular wire 82 are fitted within a slot 6 of a stator core 7, and at a fitting portion 8c where the protrusion 8a and the groove 8b are fitted together, a first side 8a1 of the protrusion 8a corresponds to a first side 8b1 of the groove 8b, and a second side 8a2 of the protrusion 8a corresponds to a second side 8b2 of the groove 8b. This allows the protrusion 8a and groove 8b (i.e., the first flat wire 81 and the second flat wire 82) to be fitted together simply by pushing the protrusion 8a into the groove 8b, making it possible to easily join the protrusion 8a and groove 8b (i.e., the first flat wire 81 and the second flat wire 82), thereby improving the conductivity reliability of the connection portion (protrusion 8a and groove 8b) of the two flat wire-shaped segment coils (the first flat wire 81 and the second flat wire 82) within the slot 6 without increasing the production labor required for the rotating motor 1.

[0027] In particular, by making the cross-section 8aa of the protrusion 8a and the cross-section 8ba of the groove 8b have the same shape (while allowing for tolerances as described above), the protrusion 8a can be pressed into the groove 8b with less force, and the bonding strength between the protrusion 8a and the groove 8b (i.e., the first flat wire 81 and the second flat wire 82) can be further improved.

[0028] The first side 8a1 of the protrusion 8a may be longer than the first side 8b1 of the groove 8b within the range of the interference fit tolerance, and similarly, the second side 8a2 of the protrusion 8a may be longer than the second side 8b2 of the groove 8b within the range of the interference fit tolerance. In this case, the protrusion 8a can be easily pressed into the groove 8b and will not easily come out of the groove 8b.

[0029] In addition, in the fitting portion 8c according to this embodiment, the third side 8a3 and the fourth side 8a4 of the protrusion 8a, and the third side 8b3 and the fourth side 8b4 of the groove 8b are oblique sides. That is, the protrusion 8a and the groove 8b have tapered portions that narrow in the same direction in the thickness direction of the first rectangular wire 81 and the second rectangular wire 82 as shown in FIG. 7, and the protrusion 8a and the groove 8b can contact (surface contact) with each other at the inclined surfaces that constitute the tapered portions. In this way, when the protrusion 8a and the groove 8b are provided with tapered portions, the contact area between the protrusion 8a and the groove 8b can be increased compared to a shape without a tapered portion, and the joint strength between the protrusion 8a and the groove 8b can be further improved, and the electrical conduction reliability can be improved.

[0030] Moreover, a cross section 8aa of the protrusion 8a and a cross section 8ba of the groove 8b are trapezoidal, and the first side 8a1 and the second side 8a2 are parallel to each other, and the first side 8b1 and the second side 8b2 are parallel to each other, thereby improving the strength of the protrusion 8a and the groove 8b.

[0031] In addition, the stator coil 8 of the rotating electric machine 1 according to this embodiment is joined by fitting the protrusion 8a and the groove 8b provided at the tip of each of the two rectangular wires. Therefore, it can be easily disassembled compared to a stator coil in which a paste-like binder having conductive particles is applied to the tip of each of the two rectangular wires and heat-cured to join them. As a result, the rotating electric machine 1 according to this embodiment can easily disassemble and take out the stator coil 8 when it is disposed of, and has excellent material reusability. In addition, the rotating electric machine 1 according to this embodiment does not need to heat-cur and join the two rectangular wires, so the burden on the environment during manufacturing can be reduced.

[0032] Second embodiment 8 is a perspective view showing the corresponding sides when the protrusion 8a and the groove 8b are fitted in the fitting portion 8c according to the second embodiment. The rotating electric machine according to this embodiment differs from the rotating electric machine 1 according to the first embodiment in the corresponding sides when the protrusion 8a and the groove 8b are fitted in the fitting portion 8c. That is, in the fitting portion 8c according to the second embodiment, the protrusion 8a is fitted in the groove 8b such that the first side 8a1 of the protrusion 8a corresponds to the second side 8b2 of the groove 8b, and the second side 8a2 of the protrusion 8a corresponds to the first side 8b1 of the groove 8b.

[0033] One end of each of the first rectangular wire 81 and the second rectangular wire 82 shown in Fig. 3 is inserted from above and below (+Y direction and -Y direction) into a predetermined slot 6 of the stator core 7. Then, in the predetermined slot 6, the protrusion 8a is fitted into the groove 8b so that the first side 8a1 corresponds to the second side 8b2, and the second side 8a2 corresponds to the first side 8b1, and they are joined by a resistance welding method. As a result, the first rectangular wire 81 and the second rectangular wire 82 are electrically connected and physically joined.

[0034] [effect] In the fitting portion 8c according to this embodiment, the first side 8a1 of the short side of the protrusion 8a corresponds to the second side 8b2 of the long side of the groove 8b, and the protrusion 8a is fitted into the groove 8b so that the second side 8a2 of the long side of the protrusion 8a corresponds to the first side 8b1 of the short side of the groove 8b. Therefore, both end portions of the second side 8a2 of the protrusion 8a abut against the end surface 82a of the groove 8b (see FIG. 5), resulting in a structure suitable for resistance welding. The stator coil 8 in which the protrusion 8a is welded to the groove 8b can improve the electrical connection reliability and joint strength.

[0035] The present invention is not limited to the above-described embodiment, and includes various modified examples. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to those including all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0036] The embodiment of the present invention may be in the following form. That is, the stator coils 8 of the first embodiment and the second embodiment may be mixed in each of the multiple slots 6 of the stator core 7. The protrusions 8a and the grooves 8b may be metal-plated. The metal plating can reduce oxidation of the joints between the protrusions 8a and the grooves 8b, and can improve the reliability of electrical continuity. The metal plating can also adjust the dimensional tolerance of the protrusions 8a and the grooves 8b to an appropriate value, thereby improving the joint strength between the protrusions 8a and the grooves 8b. For the metal plating, tin, silver, zinc, nickel, chromium, gold, and the like, as well as composites or composite layers thereof, can be used, and tin is particularly preferable from the viewpoints of oxidation inhibition, electrical continuity, and cost.

[0037] Also, an embodiment has been shown in which the protrusions 8a are provided on both ends of the first rectangular wire 81, and the grooves 8b are provided on both ends of the second rectangular wire 82. However, this is not limited thereto, and the grooves 8b may be provided on the other end of the first rectangular wire 81, and the protrusions 8a may be provided on the other end of the second rectangular wire 82.

[0038] Also, an embodiment has been shown in which the first flat wire 81 and the second flat wire 82 are inserted and fitted into any of the multiple slots 6 of the stator core 7 to form the distributed winding of the stator coil 8. However, this is not limited to this, and the first flat wire 81 and the second flat wire 82 can also be inserted and fitted into two adjacent slots 6 of the multiple slots 6 of the stator core 7 to form the concentrated winding of the stator coil 8. [Explanation of symbols]

[0039]

[0033] 1... rotating electric machine, 2... stator, 3... rotor, 6... slot, 7... stator core, 8... stator coil, 8a... protrusion, 8a1... first side, 8a2... second side, 8a3... third side, 8a4... fourth side, 8aa... cross section, 8b... groove, 8b1... first side, 8b2... second side, 8b3... third side, 8b4... fourth side, 8ba... cross section, 8c... fitting portion, 81... first rectangular wire, 81a... end face, 82... second rectangular wire, 82a... end face, 821... first side, 822... second side

Claims

1. A first rectangular wire having a protrusion at one end; A second rectangular wire having a groove at one end; a fitting portion in which the protrusion is fitted into the groove, a cross-sectional shape of each of the protrusions and the grooves is rectangular, the rectangle having a first side, a second side opposed to the first side and longer than the first side, and a third side and a fourth side connecting the first side and the second side, respectively, and opposed to each other; A rotating electric machine characterized in that, in the fitting portion, a first side of the protrusion portion corresponds to a second side of the groove portion, and the protrusion portion is fitted into the groove portion so that a second side of the protrusion portion corresponds to a first side of the groove portion.

2. 2. The rotating electric machine according to claim 1, The rotating electric machine according to claim 1, wherein the rectangle is a trapezoid, and the first side and the second side are parallel to each other.

3. 2. The rotating electric machine according to claim 1, a third side and a fourth side of the protrusion and a third side and a fourth side of the groove each form an oblique side.

4. 2. The rotating electric machine according to claim 1, The rotating electric machine according to claim 1, wherein the projection and the groove are joined to each other by a resistance welding method in the fitting portion.

5. 2. The rotating electric machine according to claim 1, A rotating electric machine, characterized in that the protrusions and the grooves are metal plated.

6. 6. The rotating electric machine according to claim 5, A rotating electric machine, wherein the metal plating is tin plating.

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