Rotating electric machine

Abstract

The invention provides a rotating electric machine. The rotating electric machine comprises a motor part; a power supply unit that supplies a current to the motor unit; a housing that houses the motor unit and the power supply unit; the grounding wire is grounded and is connected with the shell; and a relay unit provided to the ground line. The ground wire has a first ground wire connecting the housing and the relay unit, and a second ground wire grounded and connected to the relay unit. The relay unit electrically cuts off the first ground line and the second ground line when the potential of the housing is less than the relay potential, and electrically connects the first ground line and the second ground line when the potential of the housing is equal to or greater than the relay potential.

Description

Technical Field

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

[0002] There is known a motor drive system in which a ferrite core is passed through a ground wire connecting a housing and the ground, to suppress noise generated in the motor from being propagated to an inverter circuit via the ground wire and the ground, the housing accommodating a motor supplied with an alternating current from the inverter circuit (for example, Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-83080 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the motor drive system as described above, since it is difficult to suppress the propagation of conducted noise having a frequency of several MHz or less to the inverter circuit, there is a risk that the conducted noise propagates to a control unit that controls the operation of the inverter circuit. When the conducted noise propagates to the control unit, the operation of the control unit becomes unstable, so that the current supplied to the motor becomes unstable, and the operation of the motor may become unstable.

[0008] One object of one aspect of the present invention is to provide a rotating electric machine that suppresses the potential of a housing accommodating a motor and a power supply unit from becoming too high while stabilizing the operation of a control unit.

[0009] Means for Solving the Problems

[0010] One aspect of the rotating electric machine of the present invention includes: a motor unit; a power supply unit that supplies current to the motor unit; a housing that houses the motor unit and the power supply unit; a ground wire that is grounded and connected to the housing; and a relay unit that is provided in the ground wire. The ground wire has: a first ground wire that connects the housing and the relay unit; and a second ground wire that is grounded and connected to the relay unit. When the potential of the housing is less than a relay potential, the relay unit electrically disconnects the first ground wire and the second ground wire, and when the potential of the housing is equal to or higher than the relay potential, the relay unit electrically connects the first ground wire and the second ground wire.

[0011] Advantages of the Invention

[0012] According to the rotating electric machine of the present embodiment, it is possible to suppress the potential of the housing accommodating the motor and the power supply unit from becoming too high while stabilizing the operation of the control unit. Description of the Drawings

[0013] Figure 1 is a schematic diagram showing a rotating electric machine according to an embodiment.

[0014] Figure 2 is a schematic diagram showing the noise of a rotating electric machine according to a comparative example.

[0015] Figure 3 is a schematic diagram showing the noise of a rotating electric machine according to an embodiment.

[0016] Figure 4 is a schematic diagram showing the flow of the emission current of a rotating electric machine according to an embodiment.

[0017] In the figure:

[0018] 10—rotating electric machine, 15—housing, 16—motor housing, 18—radiator, 20—motor section, 28—relay section, 30—power supply section, 33—power module section, 45—ground wire, 46—first ground wire, 48—second ground wire, Vh—potential of the housing, Vr—relay potential. Detailed Embodiment

[0019] Hereinafter, with reference to the drawings, a rotating electric machine according to an embodiment of the present invention will be described. In addition, the scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. In the following drawings, in order to facilitate understanding of each structure, the scale, quantity, etc. may be different from the actual structure.

[0020] Figure 1 is a schematic diagram showing the rotating electric machine 10 according to the present embodiment. The rotating electric machine 10 is a driving device mounted on a vehicle and rotates the axle of the vehicle. The vehicle on which the rotating electric machine 10 is mounted is a vehicle using the motor section 20 as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV). In the present embodiment, the rotating electric machine 10 includes a housing 15, a motor section 20, a power supply section 30, a control section 26, a ground wire 45, and a relay section 28.

[0021] The housing 15 houses the motor section 20 and the power supply section 30 therein. In the present embodiment, the housing 15 has a motor housing 16, a power supply housing 17, and a radiator 18. In the present embodiment, the motor housing 16, the power supply housing 17, and the radiator 18 are electrically connected to each other. The motor housing 16, the power supply housing 17, and the radiator 18 may not be electrically connected to each other.

[0022] The motor housing 16 internally houses the motor unit 20. In the present embodiment, the motor housing 16 is made of metal. The motor housing 16 has electrical conductivity. The power supply housing 17 internally houses the power supply unit 30. The power supply housing 17 may be made of a metal material or a resin material. The radiator 18 is disposed inside the power supply housing 17. In the present embodiment, the radiator 18 is made of metal. The radiator 18 has electrical conductivity. The radiator 18 holds the power module unit 33 described later. The radiator 18 dissipates the heat generated in the power module unit 33.

[0023] The motor unit 20 is housed inside the motor housing 16. The motor unit 20 is connected to the axle of the vehicle described above. The motor unit 20 rotates the axle. The motor unit 20 has a rotor and a stator (not shown). The stator has a plurality of coil portions 21. The plurality of coil portions 21 include each of a U-phase coil, a V-phase coil, and a W-phase coil. When an alternating current is supplied from the power supply unit 30 to each of the coil portions 21, a rotor (not shown) rotates. The rotation of the rotor is transmitted to the axle of the vehicle.

[0024] When alternating current power is supplied to each of the coil portions 21, noise is generated in each of the coil portions 21. The noise generated in each of the coil portions 21 propagates to the motor housing 16 via the parasitic capacitance formed between each of the coil portions 21 and the motor housing 16.

[0025] The power supply unit 30 generates a supply current based on the current supplied from the external power supply 25 and supplies the supply current to each of the coil portions 21 of the motor unit 20. In the present embodiment, the supply current is an alternating current or a direct current. The power supply unit 30 has a plurality of diodes 31, capacitors 32, and a power module unit 33.

[0026] The plurality of diodes 31 are respectively electrically connected to the external power supply 25 via power lines 41. The plurality of diodes 31 rectify the current supplied from the external power supply 25. The capacitors 32 smooth the current flowing into the power module unit 33.

[0027] The power module unit 33 generates a supply current based on the current supplied from the external power source 25. That is, the power module unit 33 generates the current supplied to the motor unit 20. The power module unit 33 is electrically connected to each coil unit 21 of the motor unit 20 via the motor line 42. Thereby, the power module unit 33 supplies the supply current to each coil unit 21. In the present embodiment, the power module unit 33 has a plurality of switch elements (not shown). The switch elements are, for example, power semiconductor elements such as insulated gate bipolar transistors (IGBTs: Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The switch elements generate a supply current based on the current supplied from the external power source 25.

[0028] When the switch elements generate a supply current, heat is generated in the switch elements. Thereby, the temperature of the power module unit 33 rises. As described above, the power module unit 33 is held by the heat sink 18. The heat of the power module unit 33 is dissipated into the air via the heat sink 18. The heat of the power module unit 33 may also be released to the refrigerant circulating in the power supply housing 17 via the heat sink 18. In addition, when the switch elements generate a supply current, noise is generated. The noise generated in the power module unit 33 propagates to the heat sink 18 via the parasitic capacitance formed between the power module unit 33 and the heat sink 18.

[0029] The control unit 26 is electrically connected to each of the plurality of switch elements included in the power module unit 33 via the control line 44. The control unit 26 controls the operation of each switch element. Thereby, the frequency and amplitude of the supply current generated by the power module unit 33 can be made to be desired frequencies and amplitudes. In the present embodiment, the control unit 26 is, for example, a microcomputer.

[0030] The external power source 25 is a power source possessed by the vehicle. The external power source 25 is, for example, a battery possessed by the vehicle. In the present embodiment, the external power source 25 supplies a direct current to the power supply unit 30. The external power source 25 may also supply an alternating current to the power supply unit 30. The external power source 25 is electrically connected to the power supply unit 30 via the power supply line 41. In the present embodiment, the rotating electric machine 10 has two power supply lines 41. Each power supply line 41 is connected in parallel between the external power source 25 and the power supply unit 30. In addition, the external power source 25 is grounded via the power supply ground line 43.

[0031] One end of the ground line 45 is connected to the housing 15, and the other end of the ground line 45 is grounded. Thereby, the housing 15 is grounded via the ground line 45. The ground line 45 has a first ground line 46 and a second ground line 48.

[0032] One end of the first ground wire 46 is connected to the housing 15, and the other end of the first ground wire 46 is connected to the relay unit 28. Thus, the first ground wire 46 connects the housing 15 and the relay unit 28. The potential of the first ground wire 46 is the same as the potential Vh of the housing 15. One end of the second ground wire 48 is connected to the relay unit 28, and the other end of the second ground wire 48 is grounded. Thus, the relay unit 28 is grounded via the second ground wire 48. Thus, the housing 15 is grounded via the first ground wire 46, the relay unit 28, and the second ground wire 48. The first ground wire 46 has a first branch portion 46a, a second branch portion 46b, and a confluence portion 46c.

[0033] One end of the first branch portion 46a is connected to the motor housing 16. Thus, the ground wire 45 is connected to the motor housing 16. The other end of the first branch portion 46a is connected to one end of the confluence portion 46c. One end of the second branch portion 46b is connected to the radiator 18. Thus, the ground wire 45 is connected to the radiator 18. The other end of the second branch portion 46b is connected to one end of the confluence portion 46c. The other end of the confluence portion 46c is connected to the relay unit 28. As described above, the relay unit 28 is grounded via the second ground wire 48. Therefore, in the present embodiment, the motor housing 16 and the radiator 18 are each grounded.

[0034] The relay unit 28 is provided on the ground wire 45. The relay unit 28 is grounded via the second ground wire 48. The relay unit 28 controls the electrical connection between the first ground wire 46 and the second ground wire 48. More specifically, when the potential of the first ground wire 46, that is, the potential Vh of the housing 15, is less than the relay potential Vr, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48. When the potential of the housing 15 is equal to or higher than the relay potential Vr, the relay unit 28 electrically connects the first ground wire 46 and the second ground wire 48. In the present embodiment, the relay unit 28 has at least any one of a varistor, a Zener diode, a relay, and an optocoupler. The relay unit 28 may have one of any one of a varistor, a Zener diode, a relay, and an optocoupler, or may have a plurality of any one of a variable resistor, a Zener diode, a relay, and an optocoupler. In addition, the relay unit 28 may have two or more of a varistor, a Zener diode, a relay, and an optocoupler.

[0035] When the relay unit 28 has a varistor, the relay potential Vr is the varistor voltage. When the potential Vh of the housing 15 is less than the relay potential Vr, that is, when the potential Vh of the housing 15 is less than the varistor voltage, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48. When the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, that is, when the potential Vh of the housing 15 is equal to or higher than the varistor voltage, the resistance of the relay unit 28 decreases. Therefore, the first ground wire 46 and the second ground wire 48 are electrically connected.

[0036] When the relay unit 28 has a Zener diode, the relay potential Vr is the Zener voltage. When the potential Vh of the housing 15 is less than the relay potential Vr, that is, when the potential Vh of the housing 15 is less than the Zener voltage, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48. Further, when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, that is, when the potential Vh of the housing 15 is equal to or higher than the Zener voltage, the resistance of the relay unit 28 decreases. Therefore, the first ground wire 46 and the second ground wire 48 are electrically connected.

[0037] When the relay unit 28 has a relay, the relay potential Vr is the voltage of the coil drive contact portion of the relay, that is, the coil voltage. In the present embodiment, when the potential Vh of the housing 15 is less than the relay potential Vr, that is, when the potential Vh of the housing 15 is less than the coil voltage, the contact portion is in an open state. Therefore, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48. In addition, when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, that is, when the potential Vh of the housing 15 is equal to or higher than the coil voltage, the coil drives the contact portion, and thus the contact portion becomes a closed state. Thereby, the relay unit 28 electrically connects the first ground wire 46 and the second ground wire 48.

[0038] When the relay unit 28 has an optocoupler, the relay potential Vr is the voltage at which a light-emitting element such as a light-emitting diode of the optocoupler emits light. In the present embodiment, when the potential Vh of the housing 15 is less than the relay potential Vr, the light-emitting element does not emit light. Therefore, the contact portion connected to the light-receiving element becomes an open state. Thereby, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48. Further, when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, the light-emitting element emits light. Therefore, the contact portion connected to the light-receiving element becomes a closed state. Thereby, the relay unit 28 electrically connects the first ground wire 46 and the second ground wire 48.

[0039] In the present embodiment, the relay potential Vr is 30 V or higher and 35 V or lower. When a user or the like of the rotating electric machine 10 touches the charged housing 15, the user or the like gets an electric shock. When the user or the like touches the housing 15 having a potential greater than 35 V, there is a concern that the user or the like may be injured due to the electric shock.

[0040] Figure 2It is a schematic diagram showing the noise N of the rotating electric machine 110 of the comparative example. Compared with the rotating electric machine 10 of the present embodiment, the rotating electric machine 110 of the comparative example does not have the relay portion 28. Therefore, in the rotating electric machine 110 of the comparative example, the housing 15 is always grounded via the ground wire 45. Other structures of the rotating electric machine 110 of the comparative example are the same as those of the rotating electric machine 10 of the above-described present embodiment.

[0041] During the operation of the rotating electric machine 110, as described above, noise N is generated in each coil portion 21. The noise N generated in each coil portion 21 is propagated to the motor housing 16 via the parasitic capacitance formed between each coil portion 21 and the motor housing 16. In addition, during the operation of the rotating electric machine 110, as described above, noise N is generated in the power module portion 33. The noise N generated in the power module portion 33 is propagated to the radiator 18 via the parasitic capacitance formed between the power module portion 33 and the radiator 18. That is, during the operation of the rotating electric machine 110, noise N is propagated to the housing 15.

[0042] As described above, the rotating electric machine 110 does not have the relay portion 28, so the housing 15 is always grounded via the ground wire 45. Therefore, the noise N propagated to the motor housing 16 and the radiator 18 is propagated to the ground E via the ground wire 45. The noise N propagated to the ground E is propagated to the power supply portion 30 via the power supply ground wire 43, the external power supply 25, and the power supply line 41. The noise N propagated to the power supply portion 30 is propagated to the control portion 26 via the control line 44. That is, the noise N generated in the motor portion 20 and the power supply portion 30 is always propagated to the control portion 26 via the ground wire 45, the ground E, the external power supply 25, and the power supply portion 30. When the noise N is propagated to the control portion 26, the operation of the control portion 26 becomes unstable. As a result, the operation of each of the plurality of switching elements included in the power module portion 33 controlled by the control portion 26 becomes unstable, so the waveform of the supply current generated by the power module portion 33 may deviate from the desired waveform. If the waveform of the supply current supplied to each coil portion 21 deviates from the desired waveform, the operation of the motor portion 20 may become unstable. As described above, in the rotating electric machine 110 of the comparative example, the housing 15 is always grounded via the ground wire 45, so the noise N is always propagated to the control portion 26. Therefore, there is a concern that the operation of the motor portion 20 is always unstable.

[0043] Figure 3 It is a schematic diagram showing the noise N of the rotating electric machine 10 of the present embodiment. In Figure 3 the potential Vh of the housing 15 is less than the relay potential Vr. Figure 4 It is a schematic diagram showing the flow of the emission current Ir of the rotating electric machine 10 of the present embodiment. In Figure 4 the potential Vh of the housing 15 is equal to or higher than the relay potential Vr.

[0044] As described above, in the present embodiment, when the potential of the housing 15 is less than the relay potential Vr, the relay unit 28 cuts off the first ground wire 46 and the second ground wire 48. Therefore, in the rotating electric machine 10 of the present embodiment, as Figure 3 shown, it is possible to suppress the noise N propagated to the motor housing 16 and the radiator 18 respectively from being propagated to the ground E via the second ground wire 48. Therefore, when the potential of the housing 15 is less than the relay potential Vr, it is possible to suppress the noise N generated in the motor unit 20 and the control unit 26 from being propagated to the control unit 26, and thus the operation of the motor unit 20 can be stabilized. At this time, since neither the motor housing 16 nor the radiator 18 is grounded, charges are accumulated in the motor housing 16 and the radiator 18 respectively. As a result, the potentials of the motor housing 16 and the radiator 18 rise. That is, the potential Vh of the housing 15 rises.

[0045] As described above, in the present embodiment, when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, the relay unit 28 connects the first ground wire 46 and the second ground wire 48. Therefore, in the rotating electric machine 10 of the present embodiment, when the potential Vh of the housing 15 rises to equal to or higher than the relay potential Vr, the housing 15 is grounded via the ground wire 45. Therefore, as Figure 4 shown, the emission current Ir flows from the motor housing 16 and the radiator 18 to the ground E via the ground wire 45 respectively. That is, in the rotating electric machine 10 of the present embodiment, when the potential Vh of the housing 15 becomes equal to or higher than the relay potential Vr, the emission current Ir flows from the housing 15 to the ground E. As a result, the potential Vh of the housing 15 can be reduced, and thus it is possible to suppress the potential Vh of the housing 15 from becoming larger than the relay potential Vr. When the potential Vh of the housing 15 drops to less than the relay potential Vr, the relay unit 28 cuts off the first ground wire 46 and the second ground wire 48.

[0046] In addition, when the first ground wire 46 and the second ground wire 48 are connected, as described above, the noise N generated in the motor unit 20 and the control unit 26 is propagated to the control unit 26. However, in the present embodiment, the first ground wire 46 and the second ground wire 48 are connected only when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr. Therefore, compared with the comparative example rotating electric machine 110 in which the first ground wire 46 and the second ground wire 48 are always connected, the frequency at which the operation of the control unit 26 becomes unstable can be reduced. Therefore, compared with the comparative example rotating electric machine 110, the operation of the motor unit 20 can be stabilized.

[0047] According to the present embodiment, the rotating electric machine 10 includes: a motor unit 20; a power supply unit 30 that supplies current to the motor unit 20; a housing 15 that houses the motor unit 20 and the power supply unit 30; a ground wire 45 that is grounded and connected to the housing 15; and a relay unit 28 that is provided on the ground wire 45. The ground wire 45 has a first ground wire 46 that connects the housing 15 and the relay unit 28 and a second ground wire 48 that is grounded and connected to the relay unit 28. When the potential Vh of the housing 15 is less than the relay potential Vr, the relay unit 28 electrically disconnects the first ground wire 46 and the second ground wire 48, and when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, the relay unit 28 electrically connects the first ground wire 46 and the second ground wire 48. Thus, when the potential Vh of the housing 15 is less than the relay potential Vr, the housing 15 is not grounded via the ground wire 45. Therefore, as described above, it is possible to suppress the noise N generated in the motor unit 20 and the power supply unit 30 from always propagating to the control unit 26 via the ground wire 45, the ground E, the external power supply 25, and the power supply unit 30. As a result, the operation of the control unit 26 can be stabilized, and thus a supply current having a desired waveform can always be supplied to the motor unit 20. Therefore, the operation of the motor unit 20 can be stabilized, and thus the operation of the rotating electric machine 10 can be stabilized. Further, when the potential Vh of the housing 15 is equal to or higher than the relay potential Vr, since the housing 15 is grounded via the ground wire 45, as described above, it is possible to cause the emission current Ir to flow from the housing 15 to the ground E. Therefore, it is possible to suppress the potential Vh of the housing 15 from becoming greater than the relay potential Vr. As a result, it is possible to suppress the potential Vh of the housing 15 from becoming excessively high, and thus even if a user or the like touches the housing 15, it is possible to suppress the user or the like from being injured.

[0048] The ground wire 45 is a wire that grounds the housing 15, and the power supply wire 41 is a wire through which current supplied from the external power supply 25 to the power supply unit 30 flows. Therefore, it is easy for the current capacity of the ground wire 45 to be smaller than the current capacity of the power supply wire 41. Further, as described above, the rotating electric machine 10 includes two power supply wires 41. Therefore, for example, compared with a rotating electric machine having a structure in which a relay unit 28 is provided in each power supply wire 41 to suppress the propagation of the noise N to the control unit 26, in the rotating electric machine 10 of the present embodiment, it is possible to reduce the current capacity of the relay unit 28 and reduce the number of relay units 28. As a result, it is possible to suppress the relay unit 28 from becoming large in size and suppress an increase in the manufacturing cost of the relay unit 28. Therefore, it is possible to suppress the rotating electric machine 10 from becoming large in size and suppress an increase in the manufacturing cost of the rotating electric machine 10.

[0049] According to the present embodiment, the housing 15 has a motor housing 16 that houses the motor unit 20, and the ground wire 45 is connected to the motor housing 16. Therefore, when the potential of the motor housing 16 is less than the relay potential Vr, it is possible to suppress the noise N generated in the motor unit 20 from always propagating to the control unit 26 via the motor housing 16, the ground wire 45, the ground E, the external power supply 25, and the power supply unit 30. Therefore, as described above, the operation of the control unit 26 can be stabilized, and thus the operation of the motor unit 20 can be stabilized. In addition, when the potential of the motor housing 16 is equal to or higher than the relay potential Vr, the motor housing 16 is grounded via the ground wire 45, so that the emission current Ir can flow from the motor housing 16 to the ground E. Therefore, it is possible to suppress the potential of the motor housing 16 from becoming too high, and thus even if a user or the like touches the motor housing 16, it is possible to prevent the user or the like from being injured.

[0050] According to the present embodiment, the power supply unit 30 has a power module unit 33 that generates the current supplied to the motor unit 20, the housing 15 has a radiator 18 that dissipates the heat of the power module unit 33, and the ground wire 45 is connected to the radiator 18. Therefore, when the potential of the radiator 18 is less than the relay potential Vr, it is possible to suppress the noise N generated in the power supply unit 30 from always propagating to the control unit 26 via the radiator 18, the ground wire 45, the ground E, the external power supply 25, and the power supply unit 30. Therefore, as described above, the operation of the control unit 26 can be stabilized, and thus the operation of the motor unit 20 can be stabilized.

[0051] According to the present embodiment, the relay potential Vr is 30 V or more and 35 V or less.

[0052] When the relay potential Vr is too small, the frequency of connection between the first ground wire 46 and the second ground wire 48 increases, so that the frequency of propagation of the noise N generated in each of the motor unit 20 and the power supply unit 30 to the control unit 26 increases. As a result, the frequency at which the operation of the control unit 26 becomes unstable increases, and thus it is difficult to stabilize the operation of the motor unit 20.

[0053] When the relay potential Vr is too large, the potential Vh of the housing 15 tends to increase, so that there is a concern that a user or the like may be injured when the user or the like touches the housing 15.

[0054] In contrast, in the present embodiment, as described above, the relay potential Vr is 30 V or more and 35 V or less, so that it is possible to suppress the relay potential Vr from becoming too small. As a result, it is possible to suppress an increase in the frequency of connection between the first ground wire 46 and the second ground wire 48, and thus it is possible to suppress an increase in the frequency of the noise N generated in each of the motor unit 20 and the power supply unit 30 from propagating to the control unit 26. As a result, it is possible to suppress an increase in the frequency at which the operation of the control unit 26 becomes unstable, and thus the operation of the motor unit 20 can be stabilized. In addition, since it is possible to suppress the relay potential Vr from becoming too large, it is possible to suppress the potential Vh of the housing 15 from becoming too large. Therefore, even if a user or the like touches the housing 15, it is possible to prevent the user or the like from being injured.

[0055] According to the present embodiment, the relay unit 28 includes at least one of a varistor, a Zener diode, a relay, and an optocoupler. Therefore, the relay unit 28 can be composed of general-purpose electronic components, and thus it is possible to more appropriately suppress an increase in the manufacturing cost of the relay unit 28.

[0056] The present invention is not limited to the above-described embodiment, and other structures and other methods can also be adopted within the scope of the technical idea of the present invention. The ground wire can be connected to the power supply housing in addition to the motor housing and the radiator. As a result, it is possible to suppress the potential of the power supply housing from becoming too large, and thus it is possible to prevent a user or the like from being injured when the user or the like touches the power supply housing. In addition, the ground wire may not be connected to either the motor housing or the radiator.

[0057] The relay potential is not limited to the present embodiment. For example, it may be less than 30 V or greater than 35 V. In addition, the relay unit may include electronic components other than a varistor, a Zener diode, a relay, and an optocoupler.

[0058] The embodiments of the present invention have been described above, but each structure and their combinations in the embodiments are examples, and additions, omissions, replacements, and other changes can be made to the structure without departing from the spirit of the present invention. In addition, the present invention is not limited by the embodiments.

[0059] In addition, the present technology can adopt the following structure.

[0060] (1) A rotating electric machine, comprising: a motor unit; a power supply unit that supplies current to the motor unit; a housing that houses the motor unit and the power supply unit; a ground wire that is grounded and connected to the housing; and a relay unit that is provided on the ground wire. The ground wire has a first ground wire connecting the housing and the relay unit and a second ground wire that is grounded and connected to the relay unit. When the potential of the housing is less than the relay potential, the relay unit electrically disconnects the first ground wire and the second ground wire. When the potential of the housing is equal to or higher than the relay potential, the relay unit electrically connects the first ground wire and the second ground wire.

[0061] (2) The rotating electric machine according to (1), wherein the housing has a motor housing that houses the motor unit, and the ground wire is connected to the motor housing.

[0062] (3) The rotating electric machine according to (1) or (2), wherein the power supply unit has a power module unit that generates the current supplied to the motor unit, the housing has a radiator that dissipates heat from the power module unit, and the ground wire is connected to the radiator.

[0063] (4) The rotating electric machine according to any one of (1) to (3), wherein the relay potential is 30 V or higher and 35 V or lower.

[0064] (5) The rotating electric machine according to any one of (1) to (4), wherein the relay unit has at least one of a varistor, a Zener diode, a relay, and an optocoupler.

Claims

1. A rotating electrical machine, characterized in that: have: Motor Department; a power supply unit that supplies current to the motor unit; a housing for housing the motor unit and the power supply unit; a grounding wire, which is grounded and connected to the housing; and a relay unit, which is provided on the ground line, The grounding wire includes a first grounding wire connecting the housing and the relay unit and a second grounding wire connected to the relay unit and grounded. When the potential of the housing is lower than the relay potential, the relay unit electrically disconnects the first ground line and the second ground line. When the potential of the housing is equal to or higher than the relay potential, the relay unit electrically connects the first ground line and the second ground line.

2. The rotating electrical machine according to claim 1, characterized in that: The housing has a motor housing for accommodating the motor unit. The grounding wire is connected to the motor housing.

3. The rotating electrical machine according to claim 1, characterized in that: The power supply unit includes a power module unit that generates a current to be supplied to the motor unit. The housing has a heat sink for dissipating heat from the power module. The grounding wire is connected to the heat sink.

4. The rotating electrical machine according to any one of claims 1 to 3, characterized in that: The relay potential is greater than or equal to 30V and less than or equal to 35V.

5. The rotating electrical machine according to any one of claims 1 to 3, characterized in that: The relay unit includes at least one of a varistor, a Zener diode, a relay, and a photocoupler.

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