Motor Unit

Abstract

To provide a motor unit capable of reducing a potential difference between a shaft and a housing over a long period of time, thereby being driven stably.SOLUTION: Included are a motor 2 including a rotor 21 including a shaft 22 rotatable about a rotation axis and a stator 25 surrounding the rotor from radially outside; a housing that accommodates the motor; bearings 41, 42 that are fixed to the housing and rotatably support the shaft 22; a resolver 28 including a resolver rotor 282 fixed to the shaft 22 and a resolver stator 281 fixed to the housing; and a contact 6 that has conductivity, is fixed to the housing, and is in contact with a contacted portion 61 provided at an end portion on one axial side of the shaft 22. The housing includes an accommodation space 55 in which the contacted portion 61 of the shaft 22 is accommodated. The contact 6 and the resolver 28 are side by side in a direction along the rotation axis in the accommodation space 55.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor unit. [Background technology]

[0002] Conventionally, motors are known that have brushes at the end of a rotor shaft that are electrically connected to a housing (see, for example, JP 2016-119760 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-119760 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the motor with the brushes described above, the contact area between the brushes and the rotor shaft is small, which increases the electrical resistance between the brushes and the rotor shaft, making it difficult for current to flow between the rotor shaft and the housing, which can cause a potential difference.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a motor unit that can be driven stably for a long period of time by keeping the potential difference between the shaft and the housing small. [Means for solving the problem]

[0006] An exemplary motor unit of the present invention includes a motor having a rotor having a shaft rotatable around a rotation axis and a stator surrounding the rotor from the radial outside, a housing that accommodates the motor, a bearing fixed to the housing and rotatably supporting the shaft, a resolver having a resolver rotor fixed to the shaft and a resolver stator fixed to the housing, and a contact member that is conductive and fixed to the housing and contacts a contacted portion provided at one axial end of the shaft. The housing has an accommodation space that accommodates the contacted portion of the shaft. The contact member and the resolver are arranged side by side in the accommodation space in a direction along the rotation axis. Effect of the Invention

[0007] According to the exemplary motor unit of the present invention, the potential difference between the shaft and the housing can be kept small for a long period of time, allowing stable driving. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a conceptual diagram of a motor unit according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along a plane including the rotation shaft of the motor unit. [Diagram 3] FIG. 3 is an exploded perspective view of the shaft. [Figure 4] FIG. 4 is a conceptual diagram of a motor unit according to a first modified example. [Diagram 5] FIG. 5 is a cross-sectional view taken along a plane including a rotation shaft of a motor unit according to a first modified example. [Figure 6] FIG. 6 is an exploded perspective view of a shaft of the first modified example. [Figure 7] FIG. 7 is a perspective view of an extension shaft. [Figure 8] FIG. 8 is a cross-sectional view of an extension shaft of the second modified example. [Figure 9] FIG. 9 is a cross-sectional view of an extension shaft of the third modified example. [Figure 10] FIG. 10 is a cross-sectional view of an extension shaft of the fourth modified example. [Figure 11] FIG. 11 is a cross-sectional view of a motor unit according to a fifth modified example. [Figure 12] FIG. 12 is a cross-sectional view of a motor unit according to a sixth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a motor unit according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention.

[0010] In this specification, the direction parallel to the rotation axis J2 of the rotor 21 of the motor 2 is defined as the "axial direction" of the motor unit 1. One axial side N and the other axial side T are defined as shown in FIG. 1. The radial direction perpendicular to the rotation axis J2 is simply referred to as the "radial direction", and the circumferential direction centered on the rotation axis J2 is simply referred to as the "circumferential direction". Furthermore, in this specification, a "parallel direction" includes not only a completely parallel direction, but also a substantially parallel direction. And "extending along" a specified direction or plane includes not only a case where it extends strictly in a specified direction, but also a case where it extends in a direction tilted within a range of less than 45° with respect to the strict direction.

[0011] <Motor unit 1> A motor unit 1 according to an exemplary embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a conceptual diagram of the motor unit 1 according to an embodiment. Fig. 2 is a cross-sectional view taken along a plane including the rotation axis J2 of the motor unit 1. Fig. 3 is an exploded perspective view of the shaft 22. Note that Fig. 1 is merely a conceptual diagram, and the arrangement and dimensions of each part are not necessarily the same as those of the actual motor unit 1.

[0012] The motor unit 1 is mounted on a vehicle that uses at least a motor as a power source, such as a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), an electric vehicle (EV), etc. The motor unit 1 is used as a power source for the above-mentioned vehicles.

[0013] 1, the motor unit 1 has a motor 2, a housing 5, and a contact member 6. The housing 5 accommodates the motor 2. The motor unit 1 further has a gear portion 3 that is connected to the other axial side T of the shaft 22 and is accommodated in the housing 5.

[0014] <Motor 2> The motor 2 is a DC brushless motor. The motor 2 is driven by power from an inverter (not shown). The motor 2 has a rotor 21 that rotates around a rotation axis J2 extending in the horizontal direction, and a stator 25 located radially outward of the rotor 21. The motor 2 is an inner rotor type motor in which the rotor 21 is rotatably disposed inside the stator 25. That is, the motor 2 has the rotor 21 having a shaft 22 that is rotatable around the rotation axis J2, and the stator 25 that surrounds the rotor 21 from the radially outward side.

[0015] <Rotor 21> The rotor 21 rotates when electric power is supplied to the stator 25. As shown in Fig. 2, the rotor 21 has a shaft 22, a rotor core 23, and a rotor magnet 24. The rotor 21 rotates about a rotation axis J2 that extends in the horizontal direction.

[0016] The shaft 22 extends around a rotation axis J2 that extends horizontally and in the width direction of the vehicle. The shaft 22 rotates around the rotation axis J2. In the motor unit 1 of this embodiment, lubricating oil CL, which serves as a coolant and will be described later, flows through a hollow portion 221 of the shaft 22. For this reason, the shaft 22 has a hollow portion 221 penetrating along the rotation axis J2 inside, and has an inlet 220 through which the lubricating oil CL flows into the hollow portion 221 on the other axial side T. That is, the shaft 22 is cylindrical and penetrates in the axial direction, and has an inlet 220 through which the lubricating oil CL flows at the end of the other axial side T. This makes it possible to prevent the hollow portion 221 of the shaft 22 from being blocked. In addition, since the shaft 22 has the hollow portion 221, it becomes possible to wire, for example, the hollow portion 221 of the shaft 22. Furthermore, the shaft 22 can be made lighter in weight.

[0017] The shaft 22 is rotatably supported in the housing 5 via a first bearing 41, a second bearing 42, a third bearing 43, and a fourth bearing 44, which will be described later. That is, the bearings 41, 42, 43, and 44 are fixed to the housing 5 and support the shaft 22 rotatably.

[0018] The shaft 22 can be divided into a portion in the motor housing space 501 and a portion in the gear housing space 502. When the shaft 22 is dividable, the divided shaft 22 can be connected by a screw coupling using, for example, male and female threads. The shaft 22 can also be connected by a fixing method such as press fitting or welding. When a fixing method such as press fitting or welding is used, serrations that combine recesses and protrusions extending in the axial direction can also be used. With this configuration, it is possible to reliably transmit rotation. The shaft 22 can also be formed as a single member.

[0019] The rotor core 23 is formed by laminating thin electromagnetic steel sheets. The rotor core 23 is a cylindrical body extending along the axial direction. A plurality of rotor magnets 24 are fixed to the rotor core 23. The plurality of rotor magnets 24 are arranged along the circumferential direction with their magnetic poles alternating.

[0020] <Stator 25> 2, the stator 25 has a stator core 26, a coil 27, and an insulator (not shown) interposed between the stator core 26 and the coil 27. The stator 25 is held in the housing 5. The stator core 26 has a plurality of magnetic pole teeth (not shown) extending radially inward from the inner circumferential surface of an annular yoke.

[0021] Coils 27 are formed by winding electric wire around the magnetic pole teeth. Coils 27 are connected to an inverter unit (not shown) via a bus bar (not shown). Coils 27 have coil ends 271 that protrude from the axial end face of stator core 26. Coil ends 271 protrude in the axial direction beyond the ends of rotor core 23 of rotor 21.

[0022] <Resolver 28> A resolver 28 (see FIGS. 2, 3, etc.) is attached to an end portion on one axial side N of the shaft 22. The resolver 28 detects the position of the rotor 21, i.e., the rotation angle. As shown in FIGS. 2 and 3, the resolver 28 has a resolver stator 281 and a resolver rotor 282. The resolver stator 281 is fixed to a bearing holder 52 (described later) of the housing 5. The resolver rotor 282 is fixed to the shaft 22. That is, the resolver 28 has the resolver rotor 282 fixed to the shaft 22 and the resolver stator 281 fixed to the housing 5.

[0023] The resolver stator 281 is annular, and the resolver rotor 282 is disk-shaped. The inner peripheral surface of the resolver stator 281 and the outer peripheral surface of the resolver rotor 282 face each other in the radial direction. The resolver stator 281 periodically detects the position of the resolver rotor 282 when the rotor 21 rotates. Thus, the resolver 28 obtains information on the position of the rotor 21 from information on the position of the resolver rotor 282.

[0024] Moreover, a bus bar (not shown) is arranged at an end portion on one axial side N inside the housing 5. The bus bar connects an inverter unit (not shown) and the coil 27, and supplies electric power to the coil 27. Electric power is supplied to the coil 27 from the one axial side N.

[0025] <Gear part 3> The gear unit 3 has a plurality of gears and is accommodated in the housing 5. As described above, the gear unit 3 is connected to the shaft 22 on the other axial side T. The gear unit 3 has a reduction portion 31 and a differential portion 32.

[0026] <Deceleration section 31> 1, the speed reducer 31 is connected to the shaft 22. The speed reducer 31 transmits the torque output from the motor 2 to the differential unit 32. The speed reducer 31 reduces the rotation speed of the motor 2 in accordance with the reduction ratio, and increases the torque output from the motor 2 in accordance with the reduction ratio.

[0027] The speed reducer 31 is a parallel shaft gear type reducer in which the axes of the gears are arranged in parallel. The speed reducer 31 has a first gear 311 which is an intermediate drive gear, a second gear 312 which is an intermediate gear, a third gear 313 which is a final drive gear, and an intermediate shaft 314.

[0028] The first gear 311 is disposed on the outer circumferential surface of the shaft 22. In the motor unit 1 of this embodiment, the first gear 311 and the shaft 22 are formed of a single member. The first gear 311 rotates together with the shaft 22 about the rotation axis J2. The intermediate shaft 314 extends along an intermediate axis J4 that is parallel to the rotation axis J2. Both axial ends of the intermediate shaft 314 are rotatably supported by the housing 5 via bearings. That is, the intermediate shaft 314 is rotatable about the intermediate axis J4.

[0029] The second gear 312 and the third gear 313 are disposed on the intermediate shaft 314. The second gear 312 meshes with the first gear 311. The third gear 313 meshes with the ring gear 321 of the differential unit 32. The torque of the shaft 22 is transmitted from the first gear 311 to the second gear 312. Then, the torque transmitted to the second gear 312 is transmitted to the third gear 313 via the intermediate shaft 314. The torque transmitted to the third gear 313 is transmitted to the ring gear 321 of the differential unit 32. In this manner, the reduction gear unit 31 transmits the torque output from the motor 2 to the differential unit 32. The gear ratio of each gear, the number of gears, and the like can be changed in various ways according to the required reduction gear ratio.

[0030] <Differential section 32> The differential part 32 transmits the torque output from the motor 2 to the output shaft 33. The output shafts 33 are attached to the left and right sides of the differential part 32, respectively. The differential part 32 has a function of transmitting the same torque to the left and right output shafts 33 while absorbing the speed difference between the left and right drive wheels, i.e., the output shafts 33, when the vehicle turns, for example. The output shaft 33 protrudes to the outside of the housing 5. A drive shaft (not shown) connected to the drive wheels of the vehicle is connected to the output shaft 33.

[0031] In addition to these, the gear portion 3 may have a parking mechanism (not shown) that locks the vehicle when the operation of the motor unit 1 is stopped.

[0032] <Housing 5> As shown in Figs. 1 and 2, the housing 5 has a housing body 51, a bearing holder 52, a cover member 53, and a gear portion accommodating portion 54. The housing body 51, the bearing holder 52, and the gear portion accommodating portion 54 are formed of a conductive material such as iron, aluminum, or an alloy thereof, in other words, a metal, but are not limited thereto. The housing body 51, the bearing holder 52, the cover member 53, and the gear portion accommodating portion 54 may be formed of the same material or different materials. It is preferable that they are formed of the same material in order to suppress bimetallic corrosion at the contact portion.

[0033] <Housing body 51> The housing body 51 has a first cylindrical portion 511, a partition wall portion 512, and a protruding portion 513. The first cylindrical portion 511 is a cylindrical body extending in the axial direction. The stator core 26 is fixed inside the housing body 51. That is, the housing 5 has the housing body 51 that holds the stator 25. The first cylindrical portion 511 has an opening on one axial side N.

[0034] The partition wall portion 512 expands radially inward from an end portion on the other axial side T of the first cylindrical portion 511. The partition wall portion 512 is provided with a through hole 514 penetrating along the rotation axis J2. The through hole 514 has a circular cross section, and a center line overlaps with the rotation axis J2. The shaft 22 is disposed penetrating the through hole 514. The shaft 22 penetrating the through hole 514 is rotatably supported by the partition wall portion 512 via the second bearing 42 and the fourth bearing 44. The second bearing 42 is disposed on the one axial side N of the partition wall portion 512, and the fourth bearing 44 is disposed on the other axial side T of the partition wall portion 512. As a result, the shaft 22 is rotatably supported at an intermediate portion in the axial direction, and therefore, when the shaft 22 rotates, vibration, deflection, and the like of the shaft 22 are suppressed.

[0035] The protruding portion 513 is flat and extends vertically downward from the other axial side T of the outer circumferential surface of the first cylindrical portion 511. In the motor unit 1 according to this embodiment, the first cylindrical portion 511, the partition wall portion 512 and the protruding portion 513 are formed from a single member. The partition wall portion 512 and the protruding portion 513 form a side plate portion 510 that closes an end portion of the gear portion accommodating portion 54 on one axial side N.

[0036] A first drive shaft passing hole 515 is formed in the protruding portion 513. The first drive shaft passing hole 515 is a hole that penetrates the protruding portion 513 in the axial direction. The output shaft 33 passes through the first drive shaft passing hole 515 in a rotatable state. An oil seal (not shown) is provided between the output shaft 33 and the first drive shaft passing hole 515 to suppress leakage of the lubricating oil CL. An axle (not shown) that rotates the wheels is connected to the tip of the output shaft 33.

[0037] <Bearing holder 52> The bearing holder 52 expands in the radial direction. The bearing holder 52 is fixed to one axial side N of the first cylindrical portion 511. The bearing holder 52 can be fixed to the first cylindrical portion 511 by, for example, fixing with a screw, but is not limited to this, and any method that can firmly fix the bearing holder 52 to the first cylindrical portion 511, such as screwing or press fitting, can be widely used.

[0038] As a result, the bearing holder 52 is electrically connected to the housing main body 51. Here, when two components are electrically connected, this includes cases where they are in physical contact and capable of conducting electricity, as well as cases where they are close enough to be at approximately the same potential. In other words, electrically connected components have the same potential or approximately the same potential. Hereinafter, when referring to being electrically connected, this is taken to mean a similar configuration. In the motor unit 1 of this embodiment, the housing main body 51 and the bearing holder 52 are at the same potential.

[0039] Also, the first cylindrical portion 511 and the bearing holder 52 are in close contact with each other. Here, close contact means that the lubricating oil CL inside the housing 5 does not leak to the outside and that there is sufficient sealing to prevent foreign matter such as water, dirt, and dust from entering from the outside. The same applies hereinafter for close contact.

[0040] The bearing holder 52 has a recess 521 recessed from a surface on one axial side N of the bearing holder 52 to the other axial side. A through hole 520 penetrating in the axial direction is formed in a bottom surface of the recess 521. The center of the through hole 520 coincides with the rotation axis J2, and the shaft 22 passes through the through hole 520. An end portion of the shaft 22 on the one axial side N is disposed inside the recess 521.

[0041] A first bearing 41 is disposed on the other axial side T of the bearing holder 52. The shaft 22 passing through the through hole 520 is rotatably supported by the bearing holder 52 via the first bearing 41. That is, the housing 5 has a bearing holder 52 that is provided on one axial side N of the housing body 51 and holds the bearing 41 on the other axial side T.

[0042] The resolver stator 281 of the resolver 28 is fixed inside the recess 521. That is, the resolver stator 281 is fixed to the bearing holder 52. When the resolver stator 281 is placed in the bearing holder 52, the center line of the resolver stator 281 coincides with the rotation axis J2. The resolver stator 281 is fixed to the bearing holder 52 by screws (not shown). Note that the method of fixing the resolver stator 281 to the bearing holder 52 is not limited to screws, and a wide variety of fixing methods can be used, such as press fitting and adhesion, that can firmly fix the resolver stator 281 to the bearing holder 52.

[0043] In the motor unit 1, a portion of the shaft 22 on the other axial side T of the rotor core 23 passes through the through hole 514, and a portion of the shaft 22 on one axial side N of the rotor core 23 passes through the through hole 520. Both sides of the shaft 22 sandwiching the rotor core 23 in the axial direction are rotatably supported by the housing 5 via a first bearing 41 and a second bearing 42. At this time, the shaft 22 is rotatable around the rotation axis J2.

[0044] <Cover member 53> The cover member 53 is attached to one axial side N of the bearing holder 52. The cover member 53 covers one axial side N of the recess 521 of the bearing holder 52 and is in close contact with the bearing holder 52. The bearing holder 52 and the cover member 53 are electrically connected. Therefore, the cover member 53 and the housing main body 51 have the same potential. The cover member 53 has a contact member fixing recess 531. The contact member fixing recess 531 is recessed from the surface of the other axial side T of the cover member 53, and has a contact member fixing recess 531 to which a contact ring 62 of the contact member 6 described later is fixed. That is, the housing 5 has the cover member 53 attached to one axial side N of the bearing holder 52 and to which the contact member 6 is fixed.

[0045] The concave portion 521 of the bearing holder 52 is covered with the cover member 53, and the area surrounded by the cover member 53 being fixed to the bearing holder 52 is the accommodation space 55. With the stator 25 of the motor 2 accommodated inside the first cylindrical portion 511, the bearing holder 52 is attached to one axial side N of the first cylindrical portion 511, and the cover member 53 is further attached to one axial side N of the bearing holder 52, so that the end of the one axial side N of the shaft 22 is accommodated in the accommodation space 55. A contacted portion 61 is formed at the end of the one axial side N of the shaft 22. That is, the housing 5 has the accommodation space 55 in which the contacted portion 61 of the shaft 22 is accommodated. Furthermore, the accommodation space 55 is formed between the cover member 53 and the bearing holder 52.

[0046] 1 and 2, the contact member 6 and the resolver 28 are arranged side by side along the rotation axis J2 in the accommodation space 55. That is, the contact member 6 and the resolver 28 are arranged side by side in the direction along the rotation axis J2 in the accommodation space 55. At this time, the contact member 6 and a contacted portion 61 provided at an end of the shaft 22 on one axial side N face each other in the radial direction. The contact ring 62 and the contacted portion 61 will be described in detail later.

[0047] Further, an annular member 56 is attached to an end of the shaft 22 on the one axial side N. The annular member 56 is disposed on the one axial side N of the resolver rotor 282. The annular member 56 covers the resolver rotor 282 from the one axial side N. That is, the housing 5 further includes the annular member 56 fixed to the shaft 22. The annular member 56 is fixed between the resolver rotor 282 fixed to the shaft 22 and the contacted portion 61, and covers a part of the resolver rotor 282 from the one axial side N. By covering a part of the resolver rotor 282 with the annular member 56, it is possible to suppress the intrusion of wear debris of the contact member 6 or the contacted portion 61 into the resolver 28. This allows the motor unit 1 to be driven stably for a long period of time.

[0048] <Gear housing 54> The gear portion accommodating portion 54 has a concave shape that opens to one axial side N. The gear portion accommodating portion 54 has a second cylindrical portion 541 and a closing portion 542. An end portion of the second cylindrical portion 541 on the one axial side N is attached to the side plate portion 510. The second cylindrical portion 541 has a shape that overlaps with the outer edge portion of the side plate portion 510 in the axial direction. The second cylindrical portion 541 is fixed to the side plate portion 510 in a state of intimate contact and electrical contact with the side plate portion 510.

[0049] The second cylindrical portion 541 is fixed to the side plate portion 510 by, for example, but not limited to, screwing. For example, any fixing method that can firmly fix the second cylindrical portion 541 to the side plate portion 510, such as welding or press fitting, can be widely used. The opening of the gear portion accommodating portion 54 is covered by the side plate portion 510.

[0050] The second cylindrical portion 541 and the closing portion 542 are formed of a single member. The closing portion 542 is in the form of a plate extending radially inward from an end portion of the second cylindrical portion 541 on the other axial side T. A space surrounded by the second cylindrical portion 541, the closing portion 542, and the side plate portion 510 is the gear portion accommodating space 502. An end portion of the shaft 22 on the other axial side T is rotatably supported by the closing portion 542 via the third bearing 43.

[0051] A second drive shaft passing hole 543 is formed in the closing portion 542. The second drive shaft passing hole 543 is a hole that penetrates the closing portion 542 in the axial direction. The output shaft 33 passes through the second drive shaft passing hole 543 in a rotatable state. An oil seal (not shown) is provided between the output shaft 33 and the second drive shaft passing hole 543 to suppress leakage of the lubricating oil CL. An axle (not shown) that rotates the wheels is connected to the tip of the output shaft 33. The output shaft 33 rotates around a differential axis J5.

[0052] <Coolant circulation> The housing 5 is filled with lubricating oil CL for lubricating the gears and bearings of the gear section 3. In the motor unit 1, oil is also used to cool the motor 2. In other words, the lubricating oil CL for lubricating the motor unit 1 is a coolant for cooling the motor.

[0053] As shown in FIG. 1, the lubricating oil CL is stored in the lower region of the gear portion accommodating space 502. That is, the cooling liquid (lubricating oil CL) that cools the stator 25 is stored inside the housing 5. A part of the differential part 32 is immersed in the lubricating oil CL stored in the lower region of the gear portion accommodating space 502. The lubricating oil CL stored in the lower region of the gear portion accommodating space 502 is scooped up by the operation of the differential part 32 and diffused inside the gear portion accommodating space 502. The oil diffused inside the gear portion accommodating space 502 is supplied to each gear arranged inside the gear portion accommodating space 502 and used for lubrication. In addition, a part of the lubricating oil CL diffused in the gear portion accommodating space 502 is also supplied to each bearing and used for lubrication.

[0054] 1, an oil reserve dish 57 is disposed in an upper region of the gear portion accommodating space 502. The oil reserve dish 57 opens upward. The lubricating oil CL that has been scooped up moves upward in the gear portion accommodating space 502 and flows into the oil reserve dish 57.

[0055] The lubricating oil CL accumulated in the oil reserve dish 57 flows into the hollow portion 221 of the shaft 22 from an inlet 220 at the end of the other axial side T of the shaft 22 via an oil supply path (not shown). The lubricating oil CL in the hollow portion 221 of the shaft 22 flows toward the one axial side N. The lubricating oil CL that flows inside the hollow portion 221 is sprayed toward the stator 25. As a result, the lubricating oil CL cools the stator 25.

[0056] Since the shaft 22 is cylindrical, even when the lubricating oil CL is caused to flow in the hollow portion 221 of the shaft 22, the lubricating oil CL can be drawn in from the inlet 220 by the negative pressure generated by the airflow escaping to one axial side N when the shaft 22 rotates. This allows the lubricating oil CL to be supplied to the entire motor 2, and the motor 2 can be stably cooled. Therefore, the motor 2 can be stably driven.

[0057] <Cooling fluid circulation section 7> The motor unit 1 has a coolant circulation section 7 that circulates the lubricating oil CL. The coolant circulation section 7 has a piping section 71, a pump 72, an oil cooler 73, and a motor oil reservoir 74.

[0058] The piping section 71 is a pipe formed in the housing 5. The piping section 71 connects the pump 72 and a motor oil reservoir 74 arranged inside the first cylindrical section 511, and supplies the lubricating oil CL to the motor oil reservoir 74. The pump 72 sucks the lubricating oil CL stored in a lower region of the gear portion accommodating space 502. The pump 72 is an electric pump, but is not limited to this. For example, the pump 72 may be configured to be driven by utilizing a part of the output of the output shaft 33 of the motor unit 1.

[0059] The oil cooler 73 is disposed between the pump 72 and the motor oil reservoir 74 of the piping section 71. That is, the lubricating oil CL sucked by the pump 72 passes through the oil cooler 73 via the piping section 71 and is sent to the motor oil reservoir 74. A refrigerant such as water supplied from the outside is supplied to the oil cooler 73. Then, heat is exchanged between the refrigerant and the lubricating oil CL to lower the temperature of the lubricating oil CL. Note that the oil cooler 73 is a liquid-cooled type using a refrigerant here, but is not limited thereto, and may be a so-called air-cooled type that is cooled by the wind generated by the vehicle. By using the oil cooler 73, the temperature of the lubricating oil CL supplied to the motor oil reservoir 74 can be lowered, and the cooling efficiency of the motor 2 can be improved.

[0060] The motor oil reservoir 74 is a tray that is disposed in an upper region of the motor accommodating space 501 and opens upward. More specifically, the motor oil reservoir 74 is disposed in the motor accommodating space 501, vertically above the stator 25. A drip hole is formed in the bottom of the motor oil reservoir 74, and the motor 2 is cooled by dripping the lubricating oil CL from the drip hole. The drip hole is formed, for example, above the coil end 271 of the coil 27 of the stator 25, and the coil 27 is cooled by the lubricating oil CL.

[0061] <Contact member 6> The contact member 6 comes into contact with a contacted portion 61 formed at an end portion on one axial side N of the shaft 22. The contacted portion 61 is formed of a material having a higher electrical conductivity than a bearing contact portion 222 that comes into contact with an inner ring of a bearing of the shaft 22. In other words, the electrical conductivity of the contacted portion 61 is higher than the electrical conductivity of the bearing contact portion 222 that comes into contact with a bearing 41 of the shaft 22. The contacted portion 61 comes into contact with a brush portion 63 of the contact member 6, which will be described later.

[0062] By making the electrical conductivity of the contacted part 61 higher than that of the bearing contact part 222 that contacts the bearing 41 of the shaft 22, much of the axial current generated in the shaft 22 can be made to flow to the contact member 6 that contacts the contacted part 61. This suppresses the potential difference between the inner ring and the outer ring of the bearing, and effectively suppresses electrolytic corrosion of the bearing. Note that although the first bearing 41 has been described, the potential difference between the inner ring and the outer ring is suppressed in the same way in other bearings, and electrolytic corrosion is suppressed.

[0063] The contacted portion 61 is, for example, a conductive film of silver, copper, or the like, and is formed by applying a metal paste. The contacted portion 61 may be formed by a film forming method such as plating or vapor deposition other than application. The electrolytic corrosion of the bearing will be described later. If the contacted portion 61 is sufficiently conductive with the contact member 6, it may be a part of the shaft 22.

[0064] 2 and 3, the contact member 6 has a contact ring 62 and a brush portion 63. The contact ring 62 is annular and made of a conductive material such as metal. The contact ring 62 is disposed in the contact member fixing recess 531 of the cover member 53. The contact ring 62 is fixed in the contact member fixing recess 531 by press-fitting. However, the fixing method is not limited to this, and any method capable of firmly fixing the contact ring 62 to the contact member fixing recess 531, such as adhesion or welding, can be widely adopted.

[0065] The brush portion 63 is made of a material that is conductive and can bend in the circumferential direction. The brush portion 63 is fixed to the inner circumferential surface of the contact ring 62 and is electrically connected to the contact ring 62. In other words, the contact member 6 is electrically connected to the housing 5 including the cover member 53.

[0066] The brush portion 63 protrudes radially inward. The length from the inner circumferential surface of the contact ring 62 to the axially inner tip of the brush portion 63 is longer than the radial distance between the contact ring 62 and the contacted portion 61. Therefore, the radially inner tip of the brush portion 63 elastically bends and comes into contact with the contacted portion 61. In other words, the contact member 6 is conductive and fixed to the housing 5. The contact member 6 comes into contact with the contacted portion 61 provided at the end of the shaft 22 on one axial side N.

[0067] Since the contacted portion 61 is formed on the outer circumferential surface of the shaft 22, even if the shaft 22 moves in the axial direction, the radially inner tip of the brush portion 63 continues to contact the contacted portion 61. In other words, even if the shaft 22 moves in the axial direction, the conductive state between the shaft 22 and the housing 5 is maintained.

[0068] In this embodiment, a wire made of carbon fiber is used as the brush part 63, but it is not limited to this and any wire made of a material that is elastically deformable and conductive can be widely used. In addition, it is not limited to a wire and may be a film having a width in the direction of the rotation axis J2 and a thickness in the circumferential direction.

[0069] 1, an end portion of the shaft body 223 on one axial side N is rotatably supported by a bearing holder 52 via a first bearing 41. The shaft 22 passes through a through hole 520 and protrudes to the one axial side N. A resolver rotor 282 of a resolver 28 is attached to the shaft 22 on the one axial side N of the through hole 520.

[0070] When the contact member 6 is attached to the contact member fixing recess 531 of the cover member 53, the radially inner tip of the brush portion 63 of the contact member 6 comes into contact with the contacted portion 61 on the outer circumferential surface of the shaft 22. Since the brush portion 63 elastically deforms, the radially inner tip of the brush portion 63 deforms along the contacted portion 61 and comes into contact with the contacted portion 61, electrically connecting the brush portion 63 and the contacted portion 61. This electrically connects the shaft 22 and the contact member 6.

[0071] Since the brush portion 63 is made of an elastically deformable material, the electrical connection between the shaft 22 and the contact member 6 is maintained even when the shaft 22 rotates. Therefore, the shaft 22 and the housing 5, i.e., the inner rings attached to the shaft 22 of each of the first bearing 41 to the fourth bearing 44 and the outer rings attached to the housing 5, are at the same potential, and electrical corrosion of the bearings due to discharge caused by the potential difference is suppressed. This suppresses variation in the rotation of the shaft 22, and the motor unit 1 can be driven stably for a long period of time. In other words, the life of the motor unit 1 can be extended.

[0072] Furthermore, since the rotor 21 and the stator 25 of the motor 2 can be stably cooled by the lubricating oil CL, it is possible to suppress a decrease in output caused by an increase in temperature of the motor 2. In other words, the motor unit 1 can suppress a decrease in output for a long period of time.

[0073] 1, the inner diameter of the end of the hollow portion 221 of the shaft 22 on one axial side N may be formed smaller than the inner diameter on the other axial side T. A step is formed on the one axial side N of the hollow portion 221. As a result, even if the one axial side N of the shaft 22 is inclined downward relative to the other axial side T, the step formed on the one axial side N of the shaft 22 suppresses the flow of the coolant CL. This suppresses the coolant CL from entering between the contact member 6 and the contacted portion 61 from the one axial side N of the shaft 22 to form an oil film, and suppresses an increase in electrical resistance between the housing 5 and the shaft 22 due to the oil film.

[0074] <First Modification> FIG. 4 is a conceptual diagram of a motor unit 1A of a first modified example. FIG. 5 is a cross-sectional view cut along a plane including the rotation axis J2 of the motor unit 1A. FIG. 6 is an exploded perspective view of the shaft 22a. FIG. 7 is a perspective view of the extension shaft 8. The motor unit 1A of the first modified example differs from the motor unit 1 shown in FIG. 1 etc. in that the shaft 22a has an extension shaft 8, and a contacted portion 61 is formed on the extension shaft 8, but has the same configuration in other respects. Therefore, the same reference numerals are used for parts of the motor unit 1A that are substantially the same as those of the motor unit 1, and detailed descriptions of the same parts will be omitted.

[0075] As shown in FIGS. 4 to 6, the shaft 22a of the motor unit 1A has a shaft main body 223 and an extension shaft 8. The extension shaft 8 is fixed to an end of the shaft main body 223 on one axial side N. The extension shaft 8 is made of a conductive material such as iron or aluminum. In order to suppress galvanic corrosion at the contact portion, it is preferable that at least the portion of the extension shaft 8 that contacts the shaft main body 223 is made of the same type of metal as the shaft main body 223. That is, the shaft 22a has the shaft main body 223 and the extension shaft 8 that is conductive and is fixed to an end of the shaft main body 223 on one axial side N.

[0076] As shown in FIGS. 4 to 7, the extension shaft 8 has a fixing portion 81 fixed to the shaft main body 223. The fixing portion 81 is inserted into the hollow portion 221 from an end portion on one axial side N of the hollow portion 221 of the shaft main body 223. The outer peripheral surface of the fixing portion 81 is in contact with and fixed to the inner peripheral surface of the hollow portion 221. That is, the extension shaft 8 has the fixing portion 81 fixed to the shaft main body 223. In addition, the contacted portion 61 is formed on the extension shaft 8. The contacted portion 61 is made of a material having a higher conductivity than the fixed portion 81. That is, the conductivity of the contacted portion 61 is higher than the conductivity of the fixed portion 81.

[0077] The extension shaft 8 has a flange portion 82 that expands radially outward from the end of one axial side N. The flange portion 82 is circular when viewed from the axial direction. In the extension shaft 8, the contacted portion 61 is formed on the outer surface of the flange portion 82. That is, the contacted portion 61 is formed on at least a part of the outer surface of the flange portion 82. The contacted portion 61 is, for example, a conductive film of silver, copper, or the like, and is formed by applying a metal paste. That is, the contacted portion 61 is a conductive film formed of a material having a higher conductivity than the material constituting the flange portion 82. Note that the contacted portion 61 may be manufactured by a film forming method such as plating or vapor deposition, in addition to coating. In this way, by forming the contacted portion 61 on a part of the outer surface of the flange portion 82, the amount of metal constituting the contacted portion 61 can be reduced, and the manufacturing cost can be reduced.

[0078] The outer diameter of the flange portion 82 is larger than the inner diameter of the hollow portion 221. In the extension shaft 8, the other axial side T of the flange portion 82 is the fixed portion 81. That is, the fixed portion 81 is formed on the other axial side T of the flange portion 82. The fixed portion 81 is also disposed in the hollow portion 221 provided at the end of the shaft main body 223 on one axial side N, and is fixed in contact with the inner surface of the hollow portion 221.

[0079] This electrically connects the shaft main body 223 and the extension shaft 8. The fixing portion 81 is fixed to the shaft 22a by press-fitting, but is not limited to this. Any fixing method can be widely adopted that can firmly fix the fixing portion 81 to the shaft main body 223 while maintaining the electrical connection between the fixing portion 81 and the shaft main body 223.

[0080] Furthermore, at least the flange portion 82 of the extension shaft 8 is disposed inside the accommodating space 55 of the housing 5. Therefore, the contacted portion 61 disposed on the flange portion 82 is disposed inside the accommodating space 55.

[0081] When the fixing portion 81 is disposed on one axial side N of the hollow portion 221 of the shaft main body 223, the flange portion 82 comes into contact with an end portion of the shaft main body 223 on one axial side N. This allows the extension shaft 8 to be positioned and fixed to the one axial side N of the shaft main body 223. This allows the flange portion 82 to be accurately opposed to the contact ring 62 in the radial direction.

[0082] Since the fixing portion 81, which is a part of the extension shaft 8, is configured to be inserted into the end of the hollow portion 221 of the shaft 22, it is possible to shorten the length of the extension shaft 8 that protrudes in the axial direction from the end of the shaft body 223. This makes it possible to electrically connect the shaft 22 and the housing 5 and suppress electrolytic corrosion of the bearings while preventing the motor unit 1 from becoming larger.

[0083] The contacted portion 61 is formed on the outer periphery of the flange portion 82. As a result, since the contacted portion 61 is the outer surface of the radially outer edge of the flange portion 82, the contact member 6 and the extension shaft 8, i.e., the shaft 22a, can maintain a conductive state even if the shaft 22a moves in the axial direction.

[0084] Since the contacted part 61 is formed using a conductive film, the material other than the contacted part 61 of the extension shaft 8 can be selected from a wide range of materials having a certain level of conductivity or higher. For example, by forming the extension shaft 8 from a member having a certain level of strength and conductivity and forming the contacted part 61 having a higher conductivity than that material, it is possible to keep the electrical resistance with the contact member 6 low while maintaining the strength of the extension shaft 8. This makes it possible to maintain a stable conductive state between the shaft 22a and the housing 5.

[0085] Furthermore, the extension shaft 8 has a through hole 80 that penetrates along the rotation axis J2. That is, the extension shaft 8 is cylindrical and penetrates in the axial direction. As shown in FIG. 5, the hollow portion 221 penetrates in the axial direction, and the shaft main body 223 has an inlet 220 for introducing coolant (lubricating oil CL) at the end on the other axial side T. The extension shaft 8 has a through hole 80. Therefore, even after the extension shaft 8 is attached to the end on the one axial side N of the shaft main body 223, the shaft 22a maintains a state of penetrating in the axial direction.

[0086] This can prevent the hollow part of the shaft main body 223 from being blocked. For example, even when wiring a conductor in the hollow part 221 of the shaft main body 223, the extension shaft 8 is unlikely to get in the way. Also, the shaft 22a can be made lighter. Furthermore, the extension shaft 8 is cylindrical and disposed on the opposite side of the inlet 220 of the shaft main body 223, so that it is unlikely to get in the way of the generation of negative pressure in the hollow part 221 when the shaft 22a rotates. As a result, the oil that flows in from the inlet 220 is pulled in the axial direction inside the hollow part 221 by the negative pressure, so that the oil can be sent to a part far from the inlet 220 in the axial direction.

[0087] 5, the inner diameter of the extension shaft 8 is smaller than the inner diameter of the hollow portion 221. With this configuration, even if the one axial side N of the shaft 22a is inclined downward relative to the other axial side T, the step caused by the difference between the inner diameter of the shaft main body 223 and the inner diameter of the extension shaft 8 can prevent the coolant (lubricating oil CL) from flowing into the inside of the extension shaft 8. This prevents the coolant (lubricating oil CL) from entering between the contact member 6 and the contacted portion 61 from the one axial side N of the shaft 22a to form an oil film, and prevents the electrical resistance between the housing 5 and the shaft 22a from increasing due to the oil film.

[0088] For example, when the motor unit 1 is used as a power source for an automobile, depending on the state in which the automobile is stopped, the one axial side N of the shaft 22a may be located lower than the other axial side T. In this case, the lubricating oil CL tends to flow through the hollow portion 221 to the one axial side N, but since the flow is restricted by the step portion, leakage of the lubricating oil CL from the end of the hollow portion 221 on the other axial side T can be suppressed.

[0089] This suppresses adhesion of insulating lubricant oil CL to brush portion 63 and suppresses an increase in electrical resistance between brush portion 63 and contacted portion 61. As a result, the potential difference between shaft 22a and housing 5 can be kept small.

[0090] Moreover, the entire extension shaft 8 may be formed from a single member. In this way, the process of joining the flange portion 82 is not necessary. This simplifies the manufacturing process of the extension shaft 8. Furthermore, since joints can be omitted, the lubricating oil CL flowing inside is less likely to leak, and a decrease in lubrication efficiency can be suppressed.

[0091] <Second Modification> Fig. 8 is a cross-sectional view of an extension shaft 8a of a second modified example. The extension shaft 8a shown in Fig. 8 has an inner flange portion 83 that protrudes radially from the middle portion of the inner surface of a through hole 80. The extension shaft 8a has the same configuration as the extension shaft 8 shown in Fig. 4 and the like, except that it has the inner flange portion 83. Therefore, the same reference numerals are used to denote parts of the extension shaft 8a that are substantially the same as those of the extension shaft 8, and detailed descriptions of the same parts will be omitted. The extension shaft 8a is also a part of the shaft 22a.

[0092] 8, the extension shaft 8a further has an annular inner flange portion 83 that expands radially inward from the inner circumferential surface of the through hole 80. By providing the inner flange portion 83, it is possible to more effectively prevent the lubricating oil CL from leaking out from the end portion on one axial side N of the shaft 22a. The inner flange portion 83 has a through hole large enough to generate a negative pressure capable of drawing the lubricating oil into the hollow portion 221 of the shaft main body 223.

[0093] For example, when the motor unit 1 is used as a power source for an automobile, one axial side N of the shaft 22a may be located lower than the other axial side T depending on the state of the automobile when it is stopped. In this case, the lubricating oil CL tends to flow through the hollow portion 221 to the one axial side N, but by providing the inner flange portion 83, it is possible to prevent the lubricating oil CL from leaking from the one axial side N of the hollow portion 221 even if the inclination of the shaft 22a is large.

[0094] The inner flange portion 83 may be formed as a single member together with the extension shaft 8a. The inner flange portion 83 may be fixed to the through hole 80 of the extension shaft 8a by an annular member. The fixing method may be press-fitting, but is not limited thereto, and any method that can firmly fix the inner flange portion 83 to the through hole 80 may be widely adopted. The inner diameter of the through hole 80 of the extension shaft 8a on one axial side N may be smaller than the inner diameter of the axial middle portion of the through hole 80 on the other axial side T. By configuring in this way, the extension shaft 8a can be manufactured more easily.

[0095] The through hole of the inner flange portion 83 preferably has an area that allows air to flow to an extent that a negative pressure sufficient to suck in the lubricating oil CL can be generated.

[0096] <Third Modification> Fig. 9 is a cross-sectional view of an extension shaft 8b of a third modified example. The extension shaft 8b shown in Fig. 9 differs from the extension shaft 8 in that it has a flange portion 82b attached to a column portion 84. In other respects, the extension shaft 8b shown in Fig. 9 has the same configuration as the extension shaft 8 shown in Fig. 4 and other figures. Therefore, the same reference numerals are used to designate parts of the extension shaft 8b that are substantially the same as those of the extension shaft 8, and detailed descriptions of the same parts will be omitted. The extension shaft 8b is also a part of the shaft 22a.

[0097] 9, the extension shaft 8b has a column portion 84 and a flange portion 82b. The flange portion 82b is annular and is press-fitted onto the outer peripheral surface of the column portion 84. The other axial side T of the column portion 84 relative to the portion to which the flange portion 82b is attached forms the fixed portion 81. The entire flange portion 82b is made of a material having a higher electrical conductivity than the column portion 84. In other words, the entire flange portion 82b forms the contacted portion 61. In other words, the flange portion 82b is made of a material having a higher electrical conductivity than the fixed portion 81.

[0098] With this configuration, it is possible to omit the step of forming a conductive film. In addition, since the entire flange portion 82b is the contacted portion 61, even if the contacted portion 61 wears due to contact with the brush portion 63 of the contact member 6, it is possible to maintain the contact state between the extension shaft 8b and the contact member 6. As a result, the conduction between the shaft 22a and the housing 5 can be maintained for a long period of time, and electrolytic corrosion of the bearing can be suppressed.

[0099] Although press-fitting has been given as a method for fixing the flange portion 82b to the column portion 84, the method is not limited to this. A wide variety of methods can be used to firmly fix the flange portion 82b to the column portion 84, such as welding, melt-adhering, and adhesive.

[0100] <Fourth Modification> Fig. 10 is a cross-sectional view of an extension shaft 8c of a fourth modified example. The extension shaft 8c shown in Fig. 10 differs from the extension shaft 8 in that it does not have a flange portion. In addition, a wide-mouth portion 225 with a wider inner diameter is provided at the end of one axial side N of the hollow portion 224 of the shaft body 223c of the shaft 22c. In other respects, the extension shaft 8c and the shaft 22c shown in Fig. 10 have the same configuration as the extension shaft 8 and the shaft 22a shown in Fig. 4 and the like. Therefore, the same reference numerals are used for the parts of the extension shaft 8c and the shaft 22c that are substantially the same as those of the extension shaft 8 and the shaft 22a, and detailed descriptions of the same parts are omitted.

[0101] 10, by providing the wide mouth portion 225 at the end portion on one axial side N of the hollow portion 224, a step portion is formed at the end portion on one axial side N of the hollow portion 224. The extension shaft 8c has a contacted portion 61 on the outer circumferential surface of the end portion on one axial side N of the cylindrical column portion 84 having a uniform outer shape over the entire axial area.

[0102] The fixing portion 81 of the extension shaft 8c is press-fitted from the end portion on one axial side N of the hollow portion 224. At this time, the end portion on the other axial side T of the extension shaft 8c comes into contact with the step portion on the other axial side T of the wide opening portion 225. This allows the extension shaft 8c to be positioned in the axial direction when being press-fitted, even if the extension shaft 8c does not have a flange portion. This allows the brush portion 63 of the contact member 6 to be accurately brought into contact with the contacted portion 61, making it possible to reduce the potential difference between the shaft 22c and the housing 5.

[0103] <Fifth Modification> Fig. 11 is a cross-sectional view of the extension shaft 8d and its surroundings of the motor unit of the fifth modified example. The contacted portion 61d and contact member 6d of the extension shaft 8d shown in Fig. 8 are different from the extension shaft 8 and contact member 6 shown in Fig. 4 and the like. Other than this, they have substantially the same configuration. Therefore, the same reference numerals are used for the portions of the extension shaft 8d that are substantially the same as those of the extension shaft 8, and detailed explanations will be omitted.

[0104] As shown in Fig. 11, the contacted portion 61d formed on the extension shaft 8d is formed on an end face of one axial side N of the flange portion 82. The contact member 6d also has a contact ring 64 and a brush portion 65. The contact ring 64 is annular and its center coincides with the rotation axis J2. The end face of the other axial side T of the contact ring 64 axially faces the end face of the one axial side N of the flange portion 82. The brush portion 65 extends from the end face of the other axial side T of the contact ring 64 to the other axial side T.

[0105] The brush part 65 is arranged in a bent state, and the tip of the brush part 65 on the other axial side T contacts the contacted part 61d of the extension shaft 8d. As a result, the brush part 65 is electrically connected to the contacted part 61d. Even if the extension shaft 8d rotates in accordance with the rotation of the shaft 22a, the contact state between the brush part 65 and the contacted part 61d continues. In other words, the shaft 22a and the housing 5 are electrically connected even while the motor 2A is driving. This makes it possible to suppress electrolytic corrosion of the bearing.

[0106] <Sixth Modification> Fig. 12 is a cross-sectional view of a motor unit 1E of a sixth modified example. As shown in Fig. 12, the motor unit 1E differs from the motor unit 1A in that the hollow portion 226 of the shaft body 223e of the shaft 22e of the motor 2D is different from the hollow portion 221 of the shaft body 223 of the shaft 22a of the motor unit 1A. The motor unit 1E also differs from the extension shaft 8 in that the extension shaft 8e does not have a through hole 80. Other than these points, the motor unit 1E has substantially the same configuration as the motor unit 1A shown in Fig. 4. Therefore, in the motor unit 1E, the parts substantially the same as those of the motor unit 1 are given the same reference numerals, and detailed description thereof will be omitted.

[0107] For example, in the motor unit 1E, if the motor 2E can be sufficiently cooled by spraying the lubricating oil CL from the coolant circulator 7, it is not necessary to flow the lubricating oil CL inside the shaft 22e. For this reason, the shaft 22e is made cylindrical, and a hollow portion 226 recessed in the axial direction is formed in an end face on one axial side N of the shaft main body 223e. The hollow portion 226 is a bottomed recessed portion recessed in the axial direction, provided in the end face on one axial side N of the shaft main body 223e. In other words, the shaft main body 223e has the hollow portion 226 that opens at least to an end on one axial side N.

[0108] In the motor unit 1E, the extension shaft 8e does not have a through hole. The extension shaft 8e is fixed to an end portion on one axial side N of the shaft main body 223e by press-fitting the fixing portion 81 of the extension shaft 8e into the hollow portion 226 of the shaft main body 223e. This allows the extension shaft 8e to be attached to the shaft main body 223e.

[0109] Since the extension shaft 8e is inserted into the hollow portion 226 at the end of the shaft main body 223e, the length of the extension shaft 8e protruding in the axial direction from the end of the shaft main body 223e can be shortened. This makes it possible to miniaturize the portion for ensuring electrical continuity between the housing 5 and the shaft 22e.

[0110] In the motor unit 1E, the extension shaft 8e is attached to one axial side N of the shaft main body 223e, but is not limited to this. The extension shaft 8e and the contact member 6 may be disposed at the end of the other axial side T. Also, the extension shaft 8e and the contact member 6 may be disposed at both ends in the axial direction.

[0111] Although the embodiments and modifications of the present invention have been described above, the configurations and their combinations in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments. [Industrial Applicability]

[0112] The motor unit of the present invention can be used, for example, as a drive motor for hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), and electric vehicles (EVs). [Explanation of symbols]

[0113] 1 Motor unit 2 Motors 21 Rotor 22 Shaft 220 Inlet 221 Hollow part 222 Bearing contact area 23 Rotor core 24 Rotor magnet 25 Stator 26 Stator core 27 Coil 271 Coil end 28 Resolver 281 Resolver stator 282 Resolver rotor 3 Gear section 31 Reduction section 311 1st Gear 312 2nd Gear 313 3rd Gear 314 Intermediate shaft 32 Differential section 321 Ring gear 33 Output shaft 41 No. 1 bearing 42 No. 2 bearing 43 3rd bearing 44 4th bearing 5. Housing 501 Motor housing space 502 Gear housing space 51 Housing body 510 Side plate part 511 First cylinder part 512 Bulkhead 513 Protrusion 514 Through hole 515 First drive shaft passage hole 52 Bearing holder 520 Through hole 521 Recess 53 Cover material 531 Contact member fixing recess 54 Gear housing 541 Second cylinder part 542 Occlusion 543 Second drive shaft passage hole 55 Containment Space 56 Annular member 57 Oil reserve dish 6 Contact members 61 Contacted part 62 Contact Ring 63 Brush section 7 Coolant circulation section 71 Piping section 72 Pump 73 Oil cooler 74 Motor Oil Reservoir 1A motor unit 2A motor 22a shaft 223 Shaft body 8 Extension shaft 80 Through Hole 81 Fixed part 82 Flange 8a Extension shaft 83 Inner flange 8b Extension shaft 82b Flange part 22c shaft 223c shaft body 8c Extension shaft 84 Column section 224 Hollow part 225 Wide Mouth 2D Motor 6d Contact member 8d Extension shaft 61d Contacted part 64 Contact Ring 65 Brush section 1E Motor unit 2E motor 226 Hollow part 8e Extension shaft 22e shaft 223e Shaft body CL lubricant

Claims

1. a motor including a rotor having a shaft rotatable around a rotation axis and a stator surrounding the rotor from the outside in the radial direction; a housing that accommodates the motor; a bearing fixed to the housing and rotatably supporting the shaft; a resolver having a resolver rotor fixed to the shaft and a resolver stator fixed to the housing; a contact member that is conductive and fixed to the housing and that comes into contact with a contacted portion provided at one end of the shaft in the axial direction, The housing includes: an accommodation space in which the contacted portion of the shaft is accommodated; A housing body that holds the stator; a bearing holder provided on one axial side of the housing body and holding the bearing on the other axial side; a cover member attached to one axial side of the bearing holder and to which the contact member is fixed, the cover member has a contact member fixing recess recessed from the surface on the other axial side, the contact member is fixed to the contact member fixing recess provided in a surface of the cover member on the other axial side, and is located on one axial side of the bearing holder, the contact member and the resolver are arranged side by side in a direction along the rotation shaft in the accommodation space, The resolver stator is fixed to the bearing holder, The accommodation space is formed between the cover member and the bearing holder of the motor unit.

2. The shaft further includes an annular member fixed thereto, The motor unit according to claim 1 , wherein the annular member is fixed between the resolver rotor fixed to the shaft and the contacted portion, and covers a portion of the resolver rotor from one axial side.

3. 3. The motor unit according to claim 1, wherein the contacted portion has a higher electrical conductivity than a bearing contact portion of the shaft that is in contact with the bearing.

4. A cooling liquid for cooling the stator is stored inside the housing, 4. The motor unit according to claim 1, wherein the shaft is cylindrical and extends in the axial direction, and has an inlet for introducing the cooling liquid at the other axial end.

5. The shaft includes a shaft body and an extension shaft that is electrically conductive and is fixed to one end of the shaft body in the axial direction; The extension shaft has a fixing portion fixed to the shaft body, The contacted portion is formed on the extension shaft, 4. The motor unit according to claim 1, wherein the contacted portion has a higher electrical conductivity than the fixed portion.

6. The shaft body has a hollow portion that is open at least at one end in an axial direction, The extension shaft is A flange portion extending radially outward from one end portion in the axial direction, The fixing portion is formed on the other axial side of the flange portion, the contacted portion is formed on at least a part of an outer surface of the flange portion, The motor unit according to claim 5 , wherein the fixing portion is disposed in the hollow portion and fixed in contact with an inner surface of the hollow portion.

7. The motor unit according to claim 6 , wherein the contacted portion is formed on an outer periphery of the flange portion.

8. 8. The motor unit according to claim 6, wherein the contacted portion has a conductive film made of a material having a higher conductivity than a material constituting the flange portion.

9. The motor unit according to claim 6, wherein the flange portion is made of a material having a higher electrical conductivity than the fixed portion.

10. A cooling liquid for cooling the stator is stored inside the housing, The hollow portion penetrates in the axial direction, the shaft body has an inlet for allowing the coolant to flow in at the other axial end, 10. The motor unit according to claim 6, wherein the extension shaft is cylindrical and extends in the axial direction.

11. The motor unit according to claim 10 , wherein an inner diameter of the extension shaft is smaller than an inner diameter of the hollow portion.

12. 12. The motor unit according to claim 10, wherein the extension shaft further includes an annular inner flange portion extending radially inward from an inner circumferential surface of the extension shaft.

13. a motor including a rotor having a shaft rotatable around a rotation axis and a stator surrounding the rotor from the outside in the radial direction; a housing that accommodates the motor; a bearing fixed to the housing and rotatably supporting the shaft; a resolver having a resolver rotor fixed to the shaft and a resolver stator fixed to the housing; a contact member that is conductive and fixed to the housing and that comes into contact with a contacted portion provided at one end of the shaft in the axial direction, the housing has an accommodation space in which the contacted portion of the shaft is accommodated, the contact member and the resolver are arranged side by side in a direction along the rotation shaft in the accommodation space, The shaft includes a shaft body and an extension shaft that is electrically conductive and is fixed to one end of the shaft body in the axial direction; The shaft body has a hollow portion that is open at least at one end in an axial direction, A cooling liquid for cooling the stator is stored inside the housing, The hollow portion penetrates in the axial direction, the shaft body has an inlet for allowing the coolant to flow in at the other axial end, The extension shaft is a cylindrical member extending in an axial direction. The extension shaft further has an annular inner flange portion extending radially inward from an inner circumferential surface of the extension shaft.

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