Electric drive built into the wheel

Abstract

The wheel-built-in electric device of the present invention is connected to the wheel, and the stator comprises: a core material, on which a coil is wound; an inverter circuit unit; a fixing component, which fixes a bearing that rotatably supports the rotating shaft of the rotor; and a stator cover, which is used to integrate the core material, the inverter circuit unit and the fixing component, and the inverter circuit unit is arranged on the first coil end side of the core material, and the fixing component and the stator cover form: an inverter flow path, which allows the refrigerant to flow to the inverter circuit unit; a relay flow path, which is connected to the inverter flow path and is connected to the second coil end side of the core material on the side opposite to the first coil end side; and a second coil end side flow path, which is connected to the relay flow path and guides the refrigerant along the second coil end.

Description

Technical Field

[0001] The invention relates to a wheel built-in electric device. Background Art

[0002] Conventionally, with the recent electrification of automobiles and airplanes, there has been a need to increase the output density of motors, and thus there has been a demand for technologies to improve the cooling performance of the motors and to reduce the size of the motors themselves.

[0003] As background technology of the present invention, the following patent documents are known. Patent document 1 discloses the following technology: annular oil jackets are provided at both ends of the stator of the motor, and an axial refrigerant flow path is provided in the stator slot. In addition, Patent document 2 discloses a technology of integrating a motor and an inverter circuit unit inside a tire wheel.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-145302

[0007] Patent Document 2: Japanese Patent Application Publication No. 2014-213622 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The technology of Patent Document 1 has a problem that, since the motor and the power converter are integrated, the distance between the two devices becomes closer, and heat is easily transferred from the motor to the power converter.

[0010] Furthermore, in the technology of Patent Document 2, in the case of an air cooling method using a heat sink, the cooling performance for the heat generated including the cooling of the motor may be insufficient, which may lead to a shortened life of the electrical components and failures.

[0011] Solutions to Solve Problems

[0012] The wheel-mounted electric device of the present invention has a rotor and a stator connected to the wheel, and the stator has: a core material, on which a coil is wound; an inverter circuit unit, which supplies power to the coil; a fixing component, which fixes a bearing that rotatably supports the rotating shaft of the rotor; and a stator cover, which is used to integrate the core material, the inverter circuit unit and the fixing component, the inverter circuit unit is arranged on the first coil end side of the core material in the axial direction of the rotating shaft, and the fixing component and the stator cover form: an inverter flow path, which allows the refrigerant to flow to the inverter circuit unit; a relay flow path, which is connected to the inverter flow path and is connected to the second coil end side of the core material on the side opposite to the first coil end side; and a second coil end side flow path, which is connected to the relay flow path and guides the refrigerant along the second coil end.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to achieve both improvement in cooling performance and reduction in size of the in-wheel electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view showing a wheel-mounted electric device according to the first embodiment of the present invention.

[0016] Figure 2 yes Figure 1 AA cross-sectional view of the stator part.

[0017] Figure 3 yes Figure 1 BB cross-sectional view of the stator part.

[0018] Figure 4 It is a cross-sectional view showing a wheel-mounted electric device according to a second embodiment of the present invention.

[0019] Figure 5 It is a cross-sectional view showing a wheel-mounted electric device according to a third embodiment of the present invention.

[0020] Figure 6 yes Figure 5 AA cross-sectional view of the stator part.

[0021] Figure 7 It is a cross-sectional view showing a wheel-mounted electric device according to a fourth embodiment of the present invention.

[0022] Figure 8 yes Figure 7 AA cross-sectional view of the stator part.

[0023] Fig. 9 It is a perspective view of a core material according to a fifth embodiment of the present invention.

[0024] Fig.10 1 is a cross-sectional view showing a wheel-mounted electric device according to a sixth embodiment of the present invention.

[0025] Fig.11 yes Fig.10 AA cross-sectional view of the stator part.

[0026] Fig.12 yes Fig.10 BB cross-sectional view of the stator part. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described using the drawings.

[0028] (Structure of In-Wheel Electric Device and First Embodiment)

[0029] use Figures 1 to 3 A first embodiment of the present invention will be described. Figure 1 is a cross-sectional view showing the structure of the in-wheel electric device according to the first embodiment, Figure 2 , Figure 3 They are Figure 1 AA section view and BB section view.

[0030] The motor 40 of the wheel-mounted electric device according to the first embodiment of the present invention is annular with the rotation axis R as the center, and is composed of a stator 1 and a rotor 2. The motor 40 of the present embodiment is an outer rotor type motor having a rotor 2 and a stator 1 connected to the wheel, and the rotor 2 is arranged on the outer peripheral side of the stator 1 with an air gap 3 therebetween.

[0031] The stator 1 includes a stator core 6, a fixing member 7, stator covers 9a and 9b, an inverter circuit unit 10, spacers 14a, 14b, and 14c, and a partition wall 23. Details of each component will be described later.

[0032] The rotor 2 includes permanent magnets 5 and is rotatably supported by a bearing 4 fixed by a fixing member 7 of the stator 1. A plurality of permanent magnets 5 are arranged in the circumferential direction of the rotor 2.

[0033] The stator core 6 is a core material, and is held by a fixing member 7 by a method such as heat-shrinking. A plurality of slots extending in the axial direction are provided at predetermined intervals along the circumferential direction on the outer peripheral side of the stator core 6. A winding 8 as a copper wire is wound around the teeth of the stator core 6 formed by the slots, and functions as a coil. In addition, the coil end on the side where the inverter circuit unit 10 exists in the axial direction of the rotating shaft R is set as a first coil end 8a, and the side opposite thereto is set as a second coil end 8b.

[0034] The fixing member 7 fixes the bearing 4 to rotatably support the rotor 2 and is arranged in parallel with the stator 1 in the radial direction of the rotation axis R to form a flow path for the refrigerant flowing in the stator 1. The refrigerant flow structure in the stator 1 will be described later.

[0035] The stator covers 9a and 9b are divided into a first cover 9a disposed on the opening side of the wheel and a second cover 9b disposed on the inner side of the wheel. In addition, the stator covers 9a and 9b form hollow areas at both ends of the axial direction in the stator 1, and are joined to a part of the fixing member 7 in a manner that surrounds the stator core 6 and the inverter circuit unit 10 disposed in the hollow area together with a part of the fixing member 7. With this structure, the stator core 6, the inverter circuit unit and the fixing member 7 are integrated.

[0036] The stator cover 9a has a flow path inlet 13 and a flow path outlet 27 for the refrigerant 16 for liquid cooling the motor 40, and the refrigerant 16 can be circulated in the stator 1 described later. In addition, the stator cover 9a expands toward the inner diameter side of the stator 1 in such a manner that the inverter circuit unit 10 that supplies power to the motor 40 is accommodated inside the stator 1 and the refrigerant 16 described later flows. Thus, an inverter circuit unit cooling flow path 24 is formed for the refrigerant to flow to the inverter circuit unit 10. In addition, the inverter circuit unit 10 is arranged on the first coil end side in the axial direction of the rotation axis R, and has a switching circuit unit (power module) 12a, 12b, 12c composed of semiconductor elements.

[0037] like Figure 1 and Figure 2 As shown in FIG. 1 , the inverter circuit unit 10 includes a ring-shaped substrate 11 having openings 15a, 15b, and 15c and switch circuit units 12a, 12b, and 12c. The switch circuit units 12a, 12b, and 12c are disposed adjacent to the openings 15a, 15b, and 15c, respectively. Thus, the refrigerant 16 flowing in from the flow path inlet 13 is Figure 1 and Figure 2 As shown by arrows 16 a , 16 b , and 16 c , the liquid flows to both surfaces of the substrate 11 through the openings 15 a , 15 b , and 15 c , thereby enabling the switch circuit portions 12 a , 12 b , and 12 c to be directly liquid-cooled from both surfaces of the substrate 11 .

[0038] The partition wall 23 separates the space having the stator core 6 and the space having the inverter circuit unit 10 in the stator 1, and the end portion is joined to the stator cover 9a and the fixing member 7. Thus, an inverter circuit unit cooling flow path 24 is formed in which the refrigerant 16 directly liquid-cools the switching circuit units 12a, 12b, and 12c, and leakage of the refrigerant to the stator core 6 side is suppressed.

[0039] Next, the refrigerant flow structure in the stator 1 will be described.

[0040] As described above, the refrigerant 16 flows in from the flow path inlet 13 provided in the stator cover 9a. The inflowing refrigerant 16 spreads in the circumferential direction on the substrate 11, and Figure 1 and Figure 2 As shown in FIG. 1 , the refrigerant 16 flows through the radial flow path divided by the spacers 14a, 14b, and 14c. Figure 1 and Figure 2 The refrigerant 16 flows as shown by arrows 16a, 16b, and 16c, cools one side of the switch circuit parts 12a, 12b, and 12c, and then passes through the openings 15a, 15b, and 15c provided in the substrate 11. Then, the refrigerant 16 goes around the back side of the substrate 11, toward the inner diameter side of the stator 1, and cools the other side of the switch circuit parts 12a, 12b, and 12c.

[0041] Then, the refrigerant 16 flows in the circumferential direction on the back side of the substrate 11, as shown in FIG. Figure 1 and Figure 2 As shown by arrow 17, the liquid flows from the relay flow path inlet 19 on the first coil end 8a side formed by the fixing member 7 to the relay flow path 18 connected to the second coil end 8b side on the opposite side. The relay flow path 18 is a groove formed in an annular shape on the outer periphery of the fixing member 7. Figure 3 As shown by arrows 22 , the refrigerant 16 flows in the relay flow path 18 in the circumferential direction toward the relay flow path outlet 20 .

[0042] Then, the refrigerant 16 reaching the relay flow path outlet 20 is Figure 1 and Figure 3 The refrigerant 16 flows into the stator cooling passage 25b as shown by the arrow 21. The stator cooling passage 25b is a cooling passage formed by the fixing member 7 and the stator cover 9b, and is connected to the relay passage 18 to guide the refrigerant 16 along the second coil end 8b. Figure 3 The liquid flows in the stator cooling flow path 25b in the circumferential direction as indicated by arrow 26.

[0043] Next, the refrigerant 16 is connected in the axial direction by the slots of the stator core 6, and is branched from the stator cooling flow path 25b on the second coil end 8b side of the stator core 6 to pass through the slots toward the stator cooling flow path 25a on the first coil end 8a side.

[0044] Finally, the refrigerant 16 passes through the flow path outlet 27 from the stator cooling flow path 25a, and a cycle of the circulation of the stator 1 is completed. Through such a refrigerant circulation structure, the coil and the switch circuit unit are in direct contact with the refrigerant 16, and the inverter circuit unit 10, the motor 40 and their refrigerant flow paths can be compactly accommodated inside the stator 1, and high cooling and miniaturization can be achieved at the same time. In addition, the relay flow path 18 shown in this embodiment cools the stator core 6 and can prevent the heat of the stator 1 from being transferred to the bearing 4, thereby thermally protecting the bearing 4.

[0045] In addition, the first embodiment described above is a case of an outer rotor type motor, so the rotor 2 is held on the outer circumference side of the stator 1 , and the relay flow path 18 is located on the inner circumference side of the stator core 6 .

[0046] According to the first embodiment of the present invention described above, the following effects are achieved.

[0047] (1) The motor 40 as the wheel-mounted electric device includes the rotor 2 and the stator 1 connected to the wheel. The stator 1 includes: a core material, namely a stator core 6, on which a winding 8 as a coil is wound; an inverter circuit unit 10, which supplies power to the winding 8; a fixing member 7, which fixes a bearing 4 that rotatably supports the rotating shaft R of the rotor 2; and stator covers 9a, 9b, which are used to integrate the core material 6, the inverter circuit unit and the fixing member 7, wherein the inverter circuit unit is arranged on the first coil end side 8a of the core material 6 in the axial direction of the rotating shaft R, and the fixing member and the stator covers 9a, 9b form: an inverter flow path 24, which allows the refrigerant to flow to the inverter circuit unit; a relay flow path 18, which is connected to the inverter flow path 24 and connected to the second coil end side 8b, which is located on the side opposite to the first coil end 8a side; and a second coil end side flow path 25b, which is connected to the relay flow path 18 and guides the refrigerant to the first coil end side 8a. As a result, it is possible to achieve both improvement in cooling performance and miniaturization of the wheel-mounted electric device.

[0048] (2) The inverter circuit of the in-wheel electric device includes a switch circuit composed of semiconductor elements, and the coil and the switch circuit are in direct contact with the refrigerant. This allows the motor 40 to be cooled efficiently.

[0049] (3) The stator covers 9a and 9b of the wheel-mounted electric device include: a first cover 9a, which is arranged on the opening side of the wheel; and a second cover 9b, which is arranged on the inner side of the wheel. The first cover 9a and the second cover 9b are respectively joined to a part of the fixing member 7 and are in contact with the refrigerant. Therefore, the entire stator 1 can be cooled down to every corner.

[0050] (4) The rotor 2 of the wheel-mounted electric device is held on the outer circumference of the stator 1, and the relay flow path 18 is located on the inner circumference of the core material 6. Thus, in the case of an external rotor, the core material 6 and the inverter circuit unit can be separated by the refrigerant, and both can be cooled efficiently.

[0051] (Second Embodiment)

[0052] use Figure 4 A second embodiment of the present invention will be described. Figure 4 It is a cross-sectional view showing the structure of a wheel-mounted electric device according to a second embodiment of the present invention.

[0053] A motor 40A of a wheel-mounted electric device according to a second embodiment of the present invention is composed of a stator 1A and a rotor 2. The stator 1A is a structure in which the stator covers 9a and 9b of the first embodiment of the present invention are provided with a vehicle outer side flange 29 and a vehicle body side flange 30. In this case, the stator covers 9a and 9b are divided into an outer peripheral cylindrical portion and a side disc portion, and the vehicle outer side flange 29 and the vehicle body side flange 30 are used to connect these two portions.

[0054] The vehicle body side flange 30 is formed as a first connection portion with a flange surface protruding outward from the outer cylindrical surface of the stator of the stator cover 9a as the first cover. In addition, the vehicle outer side flange 29 is formed as a second connection portion with a flange surface provided inside the outer cylindrical surface of the stator cover 9b as the second cover.

[0055] According to the second embodiment of the present invention described above, the following effects are achieved.

[0056] (5) The first cover 9a of the wheel-mounted electric device has a first connection portion that protrudes outward from the outer peripheral cylindrical surface of the stator 1A, and the second cover has a second connection portion that is provided on the inner side of the outer peripheral cylindrical surface. Therefore, in the case where the motor 40 is an outer rotor type, the stator 1 can be inserted into the inner diameter side of the rotor 2 without interfering with the outer side flange 29 of the vehicle. In addition, when the inverter circuit unit 10 is accommodated in the stator cover 9a, the vehicle body side flange 30 and the substrate 11 of the inverter circuit unit 10 will not interfere. As a result, the assemblability of the outer rotor type motor in which the inverter circuit unit 10 is accommodated in the stator cover can be improved.

[0057] (Third Embodiment)

[0058] use Figure 5 , Figure 6 A third embodiment of the present invention will be described. Figure 5 is a cross-sectional view showing the structure of a wheel-mounted electric device according to a third embodiment of the present invention. Figure 6 yes Figure 5 AA section view.

[0059] A motor 40B of a wheel-mounted electric device according to a third embodiment of the present invention is composed of a stator 1B and a rotor 2. The stator 1B is provided with a plurality of substrate support portions 31 for supporting the substrate 11 of the inverter circuit portion 10 in the circumferential direction on the fixing member 7 of the first embodiment of the present invention. Figure 5 , Figure 6 As shown, the base plate 11 is fixed to the base plate support portion 31 by base plate fixing bolts 32a, 32b, 32c, and 32d.

[0060] like Figure 5 As shown, the substrate support portion 31 is provided as a circuit support portion that protrudes from the inner diameter side of the relay flow path 18 and supports the inverter circuit portion 10, whereby the inverter circuit portion 10 is divided into a first circuit portion and a second circuit portion in the radial direction of the rotation axis R. The second circuit portion is arranged on the inner circumference side of the substrate support portion 31b. With this structure, the heat from the stator core 6 is cooled and removed by the relay flow path 18, so that the heat is difficult to be transferred to the second circuit portion in the substrate 11.

[0061] In addition, in the substrate 11, a first circuit portion is provided on the outer peripheral side of the substrate support portion 31b, and the first circuit portion is provided with components with relatively high heat resistance, and a second circuit portion is provided on the inner peripheral side of the substrate support portion 31b, and the second circuit portion is provided with low heat resistance components 35 such as capacitors. Thus, the low heat resistance components 35 can be protected from heat.

[0062] According to the third embodiment of the present invention described above, the following effects are achieved.

[0063] (6) The fixing member 7 of the in-wheel electric device has a circuit support portion 31 that protrudes from the inner diameter side of the relay flow path 18 toward the inverter circuit portion 10 and supports the inverter circuit portion 10. The inverter circuit portion 10 has a first circuit portion that is arranged on the outer peripheral side of the circuit support portion 31, and a second circuit portion that is arranged on the inner peripheral side of the circuit support portion 31. Therefore, components with high heat resistance and components without such heat resistance can be arranged separately.

[0064] (7) Low heat-resistant components 35 having lower heat resistance than components arranged in the first circuit section are arranged in the second circuit section of the in-wheel electric device. Therefore, low heat-resistant components 35 such as capacitors can be protected from heat.

[0065] (Fourth Embodiment)

[0066] use Figure 7 , 8 A fourth embodiment of the present invention will be described. Figure 7 is a cross-sectional view showing the structure of a wheel-mounted electric device according to a fourth embodiment of the present invention. Figure 8yes Figure 7 AA section view.

[0067] A motor 40C of a wheel-mounted electric device according to a fourth embodiment of the present invention is composed of a stator 1C and a rotor 2. The stator 1C is provided with an annular substrate support portion 33 on the fixing member 7 of the first embodiment of the present invention, and the annular substrate support portion 33 is a first circuit support portion that protrudes from the inner diameter side of the relay flow path 18 to the inverter circuit portion 10 and supports the substrate 11 of the inverter circuit portion 10. In addition, as a second circuit support portion that protrudes from the first cover 9a, an annular support member 34 is inserted between the substrate 11 and the stator cover 9a on the vehicle body side, and the substrate 11 and the annular support member 34 are fixed to the annular substrate support portion 33 by substrate fixing bolts 32.

[0068] The substrate 11 has a structure having a clamped portion clamped by the annular substrate support portion 33 and the annular support member 34. Through this structure, the inverter circuit portion 10 can be divided into a first circuit portion provided on the outer peripheral side of the clamped portion and a second circuit portion provided on the inner peripheral side of the clamped portion. As a result, the second circuit portion is less heat-resistant than the first circuit portion, so the low-heat-resistant component accommodating space 36 accommodating the low-heat-resistant component 35 can be completely isolated from the inverter circuit cooling flow path 24. In addition, in the case where the low-heat-resistant component 35 has no resistance to the cooling refrigerant (for example, oil resistance when the refrigerant is oil), the low-heat-resistant component 35 can be prevented from being exposed to the cooling refrigerant, for example, only the second circuit portion can be air-cooled.

[0069] According to the fourth embodiment of the present invention described above, the following effects are achieved.

[0070] (8) The fixing member 7 of the in-wheel electric device has a first circuit support portion 33, which protrudes toward the inverter circuit portion 10 on the inner peripheral side of the relay flow path 18 and supports the inverter circuit portion 10, and the first cover 9a has a second circuit support portion 34, which is arranged opposite to the first circuit support portion 33 and protrudes toward the inverter circuit portion 10 in the opposite direction to the first circuit support portion 33, and the inverter circuit portion 10 has a clamped portion, which is clamped by the first circuit support portion 33 and the second circuit support portion 34, and the clamped portion has: a first circuit portion, which sets the inverter circuit portion 10 on the outer peripheral side of the clamped portion, and a second circuit portion, which sets the inverter circuit portion 10 on the inner peripheral side of the clamped portion, and the second circuit portion has lower heat resistance than the first circuit portion. As a result, the second circuit portion can be completely isolated from the first circuit portion, and low heat-resistant components can be arranged in the second circuit portion.

[0071] (9) The second circuit section of the in-wheel electric device is of air-cooling type. Therefore, components that are not resistant to the cooling refrigerant can be arranged in the second circuit section.

[0072] (Fifth Embodiment)

[0073] use Fig. 9 A fifth embodiment of the present invention will be described. Fig. 9 It is a perspective view of a core material 6D according to a fifth embodiment of the present invention.

[0074] The core material 6D is located on the outer peripheral side of the stator core 6 in the first embodiment of the present invention. The stator covers 9a and 9b as the first cover and the second cover are formed of the outer peripheral cylindrical part by the cylindrical cover component, and the axial direction is formed by the metal bracket component. The cylindrical cover component uses a separate resin material 37 formed by transfer molding. By implementing such molding, the outer peripheral part of the stator 1 facing the rotor 2 will not be exposed to a strong alternating magnetic field, and eddy current loss will not be generated by using metal parts in this part. As a result, problems such as temperature rise and efficiency reduction can be avoided.

[0075] According to the fifth embodiment of the present invention described above, the following effects are achieved.

[0076] (10) The first cover 9a and the second cover 9b of the in-wheel electric device respectively include: a cylindrical cover member forming an outer peripheral cylindrical portion arranged along the outer peripheral surface of the core material; and a metal bracket member arranged along the axial end surface of the core material, and the cylindrical cover member is made of resin material 37. As a result, eddy current loss is not generated, so that the temperature increase of the motor 40 and the reduction of efficiency can be avoided.

[0077] (Sixth Embodiment)

[0078] use Figures 10-12 A sixth embodiment of the present invention will be described. Fig.10 is a cross-sectional view showing the structure of a wheel-mounted electric device according to a sixth embodiment, Fig.11 , Fig.12 They are Fig.10 AA section view and BB section view.

[0079] A motor 40E as a wheel-mounted electric device according to the sixth embodiment of the present invention is an inner rotor type motor which is different from the outer rotor type motor of the first embodiment.

[0080] The motor 40E is composed of a stator 1E and a rotor 2E. The rotor 2E is disposed on the inner circumference of the stator 1E via an air gap 3, and the rotor 2E is rotatably supported by a bearing 4E. The stator core 6 is held by a stator frame 28 by shrink fitting or the like.

[0081] Since the radial position of the relay flow path inlet 19 is different, spacers 14 d , 14 e , and 14 f are provided in place of the spacer 14 c to guide the refrigerant 16 to the relay flow path inlet 19 .

[0082] In this embodiment, the refrigerant flows in from the outer peripheral side of the stator cooling flow path 25b. Therefore, the rotor 2 is held on the inner peripheral side of the motor 40, and the relay flow path 18E is located on the outer peripheral side of the core material 6. Thus, even if the motor is an inner rotor type, the inverter circuit unit 10 and the core material 6 and their refrigerant flow paths can be compactly accommodated inside the housing of the stator 1, and high cooling and miniaturization of the motor 40 can be achieved at the same time.

[0083] According to the sixth embodiment of the present invention described above, the following effects are achieved.

[0084] (11) The rotor 2E of the in-wheel electric device E is held on the inner circumference side of the motor 40E, and the relay flow path 18E is located on the outer circumference side of the core member 6. Therefore, even in the case of the inner rotor type motor 40E, a flow structure of the refrigerant that can circulate in the stator 1E can be realized.

[0085] Above, each embodiment and various modifications are only an example, and the present invention is not limited to these contents as long as the features of the invention are not impaired. At the same time, various embodiments and modifications are described in the above, but the present invention is not limited to these contents. Other modes considered within the scope of the technical idea of ​​the present invention are also included in the scope of the present invention.

[0086] Explanation of symbols

[0087] 1, 1A, 1B, 1C, 1E: stator; 2, 2E: rotor; 3: air gap; 4, 4E: bearing; 5, 5E: permanent magnet; 6, 6D: stator core (core material); 7, 7B, 7C: fixing member; 8: winding; 8a: first coil end; 8b: second coil end; 9a, 9b: stator cover; 10: inverter circuit; 11: substrate; 12a, 12b, 12c: switch circuit; 13: flow path inlet; 14a, 14b, 14c, 14d, 14e, 14f: spacer; 15a, 15b, 15c: opening of substrate; 16: refrigerant; 16a, 16b, 16c: flow direction of refrigerant; 17: flow direction of refrigerant flowing into the relay flow path inlet; 18, 18E: relay flow 1: a flow path of the inverter circuit; 2: a stator cooling flow path; 2: a stator cooling flow path; 2: a stator cooling flow path 25b; 2: a stator cooling flow path 25b; 27: a flow path outlet; 28: a stator frame; 29: a vehicle outer side flange; 30: a vehicle body side flange; 31, 31b: a substrate support portion; 32a, 32b, 32c, 32d: a substrate fixing bolt; 33: an annular substrate support portion; 34: an annular support member; 35: a low heat-resistant component (capacitor); 36: a low heat-resistant component accommodation space; 37: a resin material; 40: a motor; R: a rotating shaft.

Claims

1. A wheel-mounted electric device having a rotor and a stator connected to the wheel, The in-wheel electric device is characterized in that: The stator has: a core material on which the coil is wound; an inverter circuit unit that supplies power to the coil; a fixing member that fixes a bearing that rotatably supports a rotating shaft of the rotor; and a stator cover for integrating the core material, the inverter circuit unit and the fixing member, The inverter circuit unit is arranged on the first coil end side of the core material in the axial direction of the rotating shaft. The fixing member and the stator cover form: an inverter flow path that allows the refrigerant to flow to the inverter circuit portion; a relay flow path that is connected to the inverter flow path and is connected to a second coil end side of the core material on the side opposite to the first coil end side; and a second coil end side flow path that is connected to the relay flow path and guides the refrigerant along the second coil end. The inverter circuit unit has a switch circuit unit composed of semiconductor elements. The coil and the switch circuit unit are in direct contact with the refrigerant.

2. The wheel-mounted electric device according to claim 1, characterized in that: The stator cover includes: a first cover disposed on the opening side of the wheel; and a second cover disposed on the back side of the wheel. The first cover and the second cover are respectively joined to a portion of the fixing member and are in contact with the refrigerant.

3. The wheel-mounted electric device according to claim 2, characterized in that: The rotor is held on the outer circumference of the stator, The relay flow path is located on the inner peripheral side of the core material.

4. The wheel-mounted electric device according to claim 3, characterized in that: The first cover has a first connection portion protruding outward from the outer peripheral cylindrical surface of the stator. The second cover has a second connection portion provided on the inner side of the outer peripheral cylindrical surface.

5. The wheel-mounted electric device according to claim 3, characterized in that: The fixing member includes a circuit support portion that protrudes toward the inverter circuit portion on the inner peripheral side of the relay flow path and supports the inverter circuit portion. The inverter circuit unit includes: a first circuit unit arranged on the outer peripheral side of the circuit support unit; and a second circuit portion disposed on an inner peripheral side of the circuit support portion.

6. The wheel-mounted electric device according to claim 5, characterized in that: A low heat-resistant component having lower heat resistance than the component arranged in the first circuit portion is arranged in the second circuit portion.

7. The in-wheel electric device according to claim 3, characterized in that: The fixing member includes a first circuit support portion that protrudes toward the inverter circuit portion on the inner peripheral side of the relay flow path and supports the inverter circuit portion. The first cover has a second circuit support portion, the second circuit support portion is arranged opposite to the first circuit support portion and protrudes toward the inverter circuit portion in a direction opposite to the first circuit support portion. The inverter circuit unit includes a clamped portion clamped by the first circuit support portion and the second circuit support portion. The clamped portion includes: a first circuit portion, which arranges the inverter circuit portion on the outer peripheral side of the clamped portion; and a second circuit unit, which disposes the inverter circuit unit on the inner peripheral side of the clamped portion, The second circuit portion has a lower heat resistance than the first circuit portion.

8. The in-wheel electric device according to claim 7, characterized in that: The second circuit unit is of air-cooling type.

9. The in-wheel electric device according to claim 3, characterized in that: The first cover and the second cover respectively have: a cylindrical cover member forming an outer peripheral cylindrical portion arranged along the outer peripheral surface of the core material; and a metal bracket member disposed along the axial end surface of the core material, The cylindrical cover component is made of resin material.

10. The in-wheel electric device according to claim 2, characterized in that: The rotor is held on the inner circumference side of the stator, The relay flow path is located on the outer peripheral side of the core material.

Images