Electrical connection structure

Abstract

Efficiently secure the welding area necessary to ensure the required joint strength. [Solution] An electrical connection structure is disclosed between lead wires of each phase drawn from a stator coil for a rotating electric machine and power lines of each phase electrically connected to a power source, wherein there are multiple lead wires for each phase, and each power line integrally has a main body and a pair of connecting terminals that are joined to the lead wire of the corresponding phase, and the main body has a longitudinal direction and a width direction, and is located between the pair of connecting terminals in the width direction.

Description

Technical Field

[0001] This disclosure relates to an electrical connection structure.

Background Art

[0002] An electrical connection structure between the lead wires of each phase drawn from a stator coil for a rotating electric machine and the power lines of each phase electrically connected to a power source is known. In this structure, one of the two lead wires drawn from the coil group of the same phase is bent so as to approach the connection end of the other lead wire at the radially outer end, and the connection ends of the two lead wires are directly welded to the power line.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art as described above, it is a structure in which two lead wires are welded to the main body of the power line, and it is difficult to efficiently secure a welding range for ensuring the required joint strength.

[0005] Therefore, on one aspect, an object of this disclosure is to efficiently secure a welding range for ensuring the required joint strength.

Means for Solving the Problems

[0006] On one aspect, an electrical connection structure between the lead wires of each phase drawn from a stator coil for a rotating electric machine and the power lines of each phase electrically connected to a power source, a plurality of the lead wires exist for each phase, the power lines integrally have a main body portion and a pair of joint terminal portions respectively joined to the lead wires of the corresponding phase for each phase, The main body portion has a longitudinal direction and a width direction, and an electrical connection structure is provided which is located between the pair of connecting terminal portions in the width direction. [Effects of the Invention]

[0007] In one respect, this disclosure makes it possible to efficiently secure the welding area necessary to ensure the required joint strength. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing the cross-sectional structure of a rotating electric machine to which the electrical connection structure of this embodiment is applied. [Figure 2] This is a circuit diagram of a Y-connected three-phase coil according to this embodiment. [Figure 3] This is a schematic perspective view showing the stator on one side of the axial direction. [Figure 4] This is an enlarged perspective view showing the connection between the lead wire and the power wire for one of the three phases shown in Figure 3. [Figure 5] This is a plan view of the connection between the lead wire and the power wire related to one phase, viewed in the radial direction. [Figure 6] This is a cross-sectional view along line AA in Figure 5. [Figure 7] This is a cross-sectional view along line BB in Figure 5. [Figure 8] This is an explanatory diagram of a modified example. [Figure 8A] This is an explanatory diagram of further variations. [Figure 9] This is a cross-sectional view along line CC in Figure 8. [Figure 10] This is an explanatory diagram of further variations. [Figure 11] This is an explanatory diagram of a comparative example, a perspective view showing an enlarged view of the connection between the leader wire and the power wire. [Figure 12] This is an explanatory diagram of another embodiment, a perspective view showing an enlarged view of the connection between the lead wire and the power wire. [Modes for carrying out the invention]

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes and the like in the drawings may be exaggerated partially for the convenience of explanation. Also, in the drawings, for ease of viewing, only some of the parts having the same attribute and existing in plurality may be labeled with reference numerals.

[0010] FIG. 1 is a cross-sectional view schematically showing a cross-sectional structure of a rotating electric machine 1 to which an electrical connection structure 10 of the present embodiment is applied.

[0011] In FIG. 1, a rotating shaft 12 of the rotating electric machine 1 is shown. In the following description, the axial direction refers to the direction in which the rotating shaft (rotation center) 12 of the rotating electric machine 1 extends, the outer side in the axial direction refers to the side away from the axial center C0 of the stator core 211, and the inner side in the axial direction refers to the side toward the axial center C0 of the stator core 211. Also, the radial direction refers to the radial direction centered on the rotating shaft 12, the outer side in the radial direction refers to the side away from the rotating shaft 12, and the inner side in the radial direction refers to the side toward the rotating shaft 12. Further, in FIG. 1, an X1 side and an X2 side are defined together with an X direction parallel to the axial direction.

[0012] The rotating electric machine 1 may be, for example, a motor for vehicle drive used in a hybrid vehicle or an electric vehicle. However, the rotating electric machine 1 may be used for any other arbitrary application.

[0013] The rotating electric machine 1 is of an inner rotor type, and the stator 21 is provided so as to surround the outer side in the radial direction of the rotor 30. The outer side in the radial direction of the stator 21 is fixed to the motor housing 10. The stator 21 includes, for example, a stator core 211 made of a laminated steel sheet of an annular magnetic material, and a plurality of slots 213 around which the stator coils 22 are wound are formed on the inner side in the radial direction of the stator core 211.

[0014] In this embodiment, the stator coil 22 is made of a rectangular wire. The stator coil 22 may be formed by segment coils including a U-shaped form when viewed perpendicular to the axial direction.

[0015] The stator coil 22 includes a slot insertion portion 222, a coil end portion 223, and a lead wire 235 as an end portion for power connection. The slot insertion portion 222 is inserted into the slot 213 of the stator core 211. The slot insertion portion 222 is arranged in each slot 213. The coil end portion 223 extends axially outwardly from the axial end face 2110 of the stator core 211 and connects between a plurality of slot insertion portions 222 located in different slots 213. The lead wire 235 is provided for each phase, and one end is electrically connected to a power source (not shown).

[0016] The rotor 30 is arranged radially inside the stator 21.

[0017] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and magnets 62.

[0018] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has a shaft hole 320, and the rotor shaft 34 is fitted into the shaft hole 320. The rotor core 32 may be fixed to the rotor shaft 34 by shrink fitting, press fitting, or the like. For example, the rotor core 32 may be coupled to the rotor shaft 34 by a key connection or a spline connection. The rotor shaft 34 is rotatably supported by the motor housing 10 via bearings 14a and 14b. Note that the rotor shaft 34 defines the rotating shaft 12 of the rotating electrical machine 1.

[0019] The rotor core 32 is formed, for example, from a laminated steel plate of an annular magnetic material. A magnet 62 is embedded inside the rotor core 32. That is, the rotor core 32 has a magnet hole 322 that penetrates in the axial direction, and the magnet 62 is inserted and fixed into the magnet hole 322. In a modified example, the rotor core 32 may be formed from a compacted body of magnetic powder that has been compressed and solidified.

[0020] Although Figure 1 shows a rotating electric machine 1 with a specific structure, the structure of the rotating electric machine 1 is not limited to this specific structure. For example, in Figure 1, the rotor shaft 34 is hollow, but it may be solid. Also, the magnets 62 may be omitted. The rotor may have field windings. Furthermore, it may be a type other than an inner rotor, for example, an outer rotor type.

[0021] Figure 2 is a circuit diagram of a Y-connected three-phase coil according to this embodiment.

[0022] As shown in Figure 2, the stator coil 22 is connected to an external power supply and is configured to receive power (for example, three-phase AC power). The stator coil 22 is configured to generate a magnetic field when power is supplied. The stator coil 22 includes a U-phase coil 230, a V-phase coil 240, and a W-phase coil 250, through which the three-phase (U-phase, V-phase, and W-phase) AC currents flow, respectively.

[0023] The U-phase coil 230 includes U1 coil section 231 and U2 coil section 232 connected in parallel to each other. The V-phase coil 240 also includes V1 coil section 241 and V2 coil section 242 connected in parallel to each other. The W-phase coil 250 also includes W1 coil section 251 and W2 coil section 252 connected in parallel to each other. The U-phase coil 230, V-phase coil 240, and W-phase coil 250 are connected in a Y-connection (star connection). In other words, a so-called "2Y" connection is realized. The AC power related to the U-phase, V-phase, and W-phase, respectively, is input from the power line 70 to the U-phase coil 230, V-phase coil 240, and W-phase coil 250, respectively. The output sides of the U-phase coil 230, V-phase coil 240, and W-phase coil 250 are connected to each other via the neutral wire terminal 262.

[0024] Figure 2 schematically shows the joint 299 between the lead wire 235 related to the U-phase coil 230 and the power line 70. The same type of joint is used for the V-phase coil 240 and the W-phase coil 250.

[0025] While this example describes the application to a "2Y" connection, it can also be applied to other connection configurations such as "4Y" and "6Y" connections.

[0026] Next, the features of this embodiment will be further explained with reference to Figures 1 and 2, and then to Figures 3 onward.

[0027] Figure 3 is a schematic perspective view showing the stator 21 on one axial side, illustrating the connection between the lead wire 235 and the power line 70 (see connection 299 in Figure 2). Figure 4 is an enlarged perspective view showing the connection between the lead wire 235 and the power line 70 for one of the three phases shown in Figure 3 (for example, the U-phase coil 230). Figure 5 is a plan view of the connection between the lead wire 235 and the power line 70 for one phase, viewed radially. Figures 6 and 7 are schematic explanatory diagrams of the range of the connection 299; Figure 6 is a cross-sectional view along line AA in Figure 5, and Figure 7 is a cross-sectional view along line BB in Figure 5.

[0028] The following explanation will mainly describe the connection method between the lead wire 235 related to the U-phase coil 230 and the power line 70 (see connection part 299 in Figure 2), but the V-phase coil 240 and W-phase coil 250 are similar.

[0029] In this embodiment, there are two lead wires 235 for each phase, and they are connected to one power line 70. The lead wires 235 are drawn out in the same manner from the end face side of the stator core 211. The lead wires 235 may be drawn out with the longer side of the rectangular cross-section facing radially.

[0030] Each power line 70 has a main body 71, a pair of connecting terminals 72, and a pair of connecting parts 73 for each phase. The main body 71, the pair of connecting terminals 72, and the pair of connecting parts 73 are integral and may be formed, for example, from a single metal sheet by press molding or the like.

[0031] The main body 71 has a longitudinal direction and a width direction, and current flows along the longitudinal direction. The longitudinal dimension is significantly larger than the width direction dimension, but they may be approximately the same or have an inverse dimensional relationship. The main body 71 may have a bent section (see, for example, bent section 710) that bends radially outward at any point along the longitudinal direction. The width direction dimension of the main body 71 may be constant along its entire length up to the other end of the main body 71 (the end on the side different from the end connected to the lead wire 235). In the example shown in Figure 3, etc., the other end of the main body 71 (the end on the side different from the end connected to the lead wire 235) is not shown, but the method of connecting this other end is arbitrary. For example, the other end of the main body 71 may be connected to the terminals of an inverter (not shown) by bolting or welding.

[0032] In the following description, "longitudinal direction" refers to the direction along the longitudinal direction of the main body 71, and "width direction" refers to the direction along the width direction of the main body 71.

[0033] The pair of connecting terminals 72 are positioned on each side of the longitudinal end 712 of the main body 71, separated in the width direction. The pair of connecting terminals 72 are individually joined to each leader wire 235. The pair of connecting terminals 72 have a shape corresponding to the end (part to be joined) of each leader wire 235 (for example, a shape that allows surface contact with the entire end of the leader wire 235).

[0034] In this way, according to this embodiment, the lead wire 235 is not directly welded to the main body 71, but rather welded (joined) to a pair of joining terminals 72 that are formed separately from and integrally with the main body 71. This makes it possible to efficiently secure the welding area necessary to ensure the required joining strength.

[0035] In this embodiment, the pair of connecting terminals 72 are positioned radially inward relative to each lead wire 235. That is, the connecting terminals 72 are joined in a state where they are in surface contact with the radially inward surface of the tip of the lead wire 235. The tip of the lead wire 235 is in a state where the insulating coating has been removed (the conductor is exposed).

[0036] The pair of connecting portions 73 connect the main body portion 71 to each of the pair of connecting terminal portions 72. The longitudinal dimension A3 of the pair of connecting portions 73 is significantly shorter than the longitudinal dimension A2 of the connecting terminal portion 72. Specifically, the connecting terminal portion 72 extends longitudinally longer than the pair of connecting portions 73 by a predetermined dimension B. The predetermined dimension B is any dimension significantly greater than 0, but is preferably set to be greater than or equal to the required welding range. This allows for the formation of welded joints 299 on both sides of the connecting terminal portion 72 in the width direction, along with the longitudinal edge of the connecting terminal portion 72. Figure 7 schematically shows the range of the joint 299 related to the longitudinal edge of the connecting terminal portion 72, and Figure 6 schematically shows the range of the joint 299 related to both sides of the connecting terminal portion 72 in the width direction. This allows for the efficient securing of the required range of each joint 299 and improves the reliability of the joints 299.

[0037] In this embodiment, as shown in Figures 3 to 5, the power line 70 has an anchor-like shape, consisting of a main body 71, a pair of connecting terminals 72, and a pair of connecting parts 73, but is not limited to this. For example, as shown in the modified power line 70A in Figure 8, the tip of the main body 71, the pair of connecting terminals 72A, and the pair of connecting parts 73A may have a C-shape. In this case, as shown in Figure 9, a cross-sectional view of CC in Figure 8, a part of the joint 299A may be formed between the longitudinal edge of the pair of connecting terminals 72A and the surface of the lead wire 235. The range of the joint 299A on both sides of the connecting terminals 72A in the width direction may be the same as in the embodiment described above (see Figure 6). In this case as well, the required range of the joint 299A can be efficiently secured, and the reliability of the joint 299A can be improved.

[0038] Furthermore, in this embodiment and the modified example shown in Figure 8, a pair of connecting parts 73, 73A are provided. However, as with the modified example shown in Figure 8A, the pair of connecting parts may be minimized or omitted, as is the case with the power line 70B.

[0039] Furthermore, in this embodiment, as shown in Figures 3 to 5, the power line 70 extends axially from the axial outer side toward the leader line 235, but is not limited to this. That is, the main body 71 has a bent forming portion 710 that extends from its longitudinal end in the same axial direction as the drawing direction of the two leader lines 235 and then bends radially outward, but is not limited to this. For example, as in the modified power line 70C shown in Figure 10, the main body 71C may extend axially from the axial inner side toward the leader line 235. That is, the main body 71C may have a bent forming portion (not shown) that extends from its longitudinal end in the opposite direction to the drawing direction of the two leader lines 235 and then bends radially outward. In this case, the joint portion 299 itself may be the same as in the embodiment described above.

[0040] Next, the effects of this embodiment will be further explained with reference to the comparative example shown in Figure 11.

[0041] The power line 70' in the comparative example differs from the power line 70 in this embodiment in that a pair of connecting terminals 72' are arranged on one side in the width direction of the main body 71'.

[0042] Incidentally, the power line 70 (and the power line 70' in the comparative example) is joined at one end to the lead line 235 and at the other end to the power supply side configuration (e.g., inverter). In such a configuration, due to assembly tolerances, dimensional tolerances, etc., forces that would not occur in the nominal state (a state without various tolerances) may act on the joint 299.

[0043] In this respect, as described above, in the comparative example, the pair of connecting terminals 72' are arranged on one side in the width direction of the main body 71', so stress concentration is likely to occur due to asymmetry. For example, stress concentration may occur on only one of the pair of connecting terminals 72', or a relatively large stress concentration may occur on the connecting portion 73'.

[0044] In contrast, in this embodiment, the power line 70 has connecting terminals 72 on both sides in the width direction of the main body 71. In particular, in this embodiment, the power line 70 has a circumferentially symmetrical shape at the end that is connected to the leader line 235. That is, the power line 70 has a symmetrical shape with respect to a straight line passing through the center of the main body 71 in the width direction (a straight line passing through the plane of the main body 71). This reduces the stress concentration that tends to occur in the comparative example described above. Furthermore, in this embodiment, the two leader lines 235 also have a circumferentially symmetrical shape. This also reduces stress concentration in the leader lines 235.

[0045] Furthermore, the power line 70' in the comparative example differs from the power line 70 in this embodiment in that it is joined to the radially outer surface of the leader line 235.

[0046] In this radial positional relationship, the analysis results showed that relatively large stresses are generated at the joint 299' when the power line 70' is shifted from its nominal position in the axial direction. For example, the analysis results showed that relatively large stresses are generated at the joint 299' when the power line 70' is located axially outward from its nominal position in the axial direction (i.e., when the joint 299' is pulled axially outward).

[0047] In contrast, in this embodiment, as described above, the power line 70 is joined to the radially inner surface of the leader line 235. In this case, even if the power line 70 is displaced from its nominal position in the axial direction, the analysis results showed that relatively large stresses are not generated at the joint 299. Therefore, according to this embodiment, a reduction in stress concentration can be expected for such deformation modes. However, in a modified example, the power line 70 may be joined to the radially outer surface of the leader line 235.

[0048] Finally, further examples will be described with reference to Figure 12.

[0049] The embodiment described above is a so-called "2Y" configuration, in which there are two lead wires 235 per phase. However, as mentioned above, this embodiment is also applicable to a "4Y" configuration, as shown in Figure 12. The power line 70D shown in Figure 12 similarly has a pair of connecting terminals 72D on both sides in the width direction of the main body 71D, and four lead wires 235 are connected to both sides in the axial direction of the pair of connecting terminals 72D. That is, a lead wire 235 is connected to both sides in the axial direction of each pair of connecting terminals 72D. In the configuration shown in Figure 12, the lead wires 235 are drawn out radially to the radially outward direction, and the power line 70D extends radially from the radially outward direction toward the lead wires 235. The two lead wires 235 on each side in the axial direction relative to the pair of connecting terminals 72D have a circumferentially symmetrical shape.

[0050] With this configuration, even if the number of lead wires 235 increases, an efficient electrical connection structure can be achieved using power lines 70D. Furthermore, since the joining method itself is substantially the same as that of the above-described embodiment, the same effects as those of the above-described embodiment can be obtained.

[0051] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above.

[0052] For example, in the embodiment described above, the main body portion 71 (and the main body portion 70C) and the connecting terminal portion 72 (and the connecting terminal portions 72A and 72D) extend in the same plane, but they may be offset in the direction perpendicular to the plane. That is, the main body portion 71 and the connecting terminal portion 72 may extend in different planes via the connecting portion 73.

[0053] The following additional information is disclosed regarding each of the above embodiments.

[0054] [Note 1] An electrical connection structure between the lead wires of each phase drawn from the stator coil of a rotating electric machine and the power lines of each phase that are electrically connected to a power supply, There are multiple such leader lines for each phase. Each power line comprises, for each phase, a main body and a pair of connecting terminals that are connected to the corresponding lead wires of that phase. The main body has a longitudinal direction and a width direction, and is an electrical connection structure located between the pair of connecting terminals in the width direction.

[0055] [Note 2] The electrical connection structure as described in Appendix 1, wherein the range of the connection between the pair of connecting terminals and the lead wire includes both sides of the pair of connecting terminals in the width direction.

[0056] [Note 3] The aforementioned power line further comprises a pair of connection points integrally for each phase, The pair of connecting terminal portions are arranged on each side in the width direction relative to the longitudinal end of the main body portion, and are spaced apart in the width direction. The pair of connecting portions connect the main body portion and each of the pair of connecting terminal portions, and the longitudinal dimension is shorter than that of the connecting terminal portion, as described in Appendix 2.

[0057] [Note 4] The pair of connecting terminals protrudes by a predetermined distance to one side in the longitudinal direction relative to the pair of connecting portions. The electrical connection structure according to any one of the appendices 1 to 3, wherein the predetermined dimension is greater than or equal to the longitudinal dimension of the connection range between the pair of connecting terminals and the lead wire.

[0058] [Note 5] The electrical connection structure according to any one of the appendices 1 to 4, wherein the longitudinal end of the main body and the pair of connecting terminals extend within the same first plane and are symmetrical with respect to a straight line in the first plane passing through the center in the width direction of the longitudinal end of the main body when viewed perpendicular to the first plane.

[0059] [Note 6] The first plane is parallel to the axial direction of the rotating electric machine, The leader line extends into a second plane parallel to the first plane, The electrical connection structure described in Appendix 5, wherein the lead wire and the pair of connecting terminals are joined in a state where they are in contact with a plane parallel to the first plane.

[0060] [Note 7] The pair of connecting terminals are joined to the radially inner surface of the lead wire, as described in Appendix 6.

[0061] [Note 8] The main body is positioned between the two leader lines in the width direction. The main body portion extends from the longitudinal end in the same axial direction as the pulling direction of the two lead wires, and then bends radially outward, as described in any one of the appendices 1 to 7. [Note 9] The electrical connection structure according to any one of the appendices 1 to 8, wherein the lead wires are joined to both sides in the thickness direction of the pair of joint terminal portions. [Explanation of Symbols]

[0062] 1 Rotating electric machine, 22 Stator coil, 235 Lead wire, 70 Power line, 71 Main body, 712 End, 72 Joint terminal, 73 Connection part

Claims

1. An electrical connection structure between the lead wires of each phase drawn from the stator coil of a rotating electric machine and the power lines of each phase that are electrically connected to a power supply, There are multiple such leader lines for each phase. Each power line comprises, for each phase, a main body and a pair of connecting terminals that are connected to the corresponding lead wires of that phase. The main body has a longitudinal direction and a width direction, and is an electrical connection structure located between the pair of connecting terminals in the width direction.

2. The electrical connection structure according to claim 1, wherein the range of the joint between the pair of connecting terminals and the lead wire includes both sides of the pair of connecting terminals in the width direction.

3. The main body is positioned between the two leader lines in the width direction. The electrical connection structure according to claim 1, wherein the main body extends from the longitudinal end in the same axial direction as the pulling direction of the two lead wires, and then bends radially outward.

4. The electrical connection structure according to any one of claims 1 to 3, wherein the lead wires are joined to both sides in the thickness direction of the pair of joint terminal portions.

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