Motor unit

Abstract

A motor unit attached to a vehicle to propel the vehicle, comprising: a motor having a rotor and stator rotatable about a motor axis as its center; a transmission mechanism transmitting the power of the motor and delivering it from an output shaft; a housing having a motor mounting section for receiving the motor and a gear mounting section for receiving the transmission mechanism; an inverter unit supplying power to the motor; and an oil cooler provided in the path of an oil channel for cooling the oil, wherein the oil cooler is attached to an outer surface of the housing and, viewed from the axial direction of the motor axis, at least a portion of the inverter unit overlaps the oil cooler; the transmission mechanism having a gear that, viewed from the axial direction of the motor axis, overlaps with at least a portion of the inverter unit.and at least part of the oil cooler is positioned further than the gear on one side in a direction that is orthogonal to both the up-down direction and the axial direction of the engine axis.

Description

TECHNICAL AREA The invention relates to a motor unit. BACKGROUND TECHNOLOGY In recent years, the development of drive systems for electric vehicles has been actively pursued. Japanese patent publication: Japanese patent application No. 2010-268633 describes a motor unit connected to a PDU (Power Drive Unit) containing an inverter. In recent years, the development of a motor unit with an integrated inverter has been initiated. State of the art document Patent document Patent document 1: Japanese patent publication no. 2010-268633 OVERVIEW OF THE INVENTION Problems to be solved by the present invention When the inverter and motor unit are integrated, the problem is that the size of the motor unit tends to increase. One of the objectives of an aspect of the present invention is to provide a motor unit in which an inverter is integrated and whose size can be reduced. Means to solve the problem The motor unit of one aspect of the present invention is mounted on a vehicle and propels the vehicle. The motor unit comprises: a motor, a gear mechanism that transmits the power of the motor and delivers it to the output shaft, a housing in which the motor and the gear mechanism are housed, and an inverter unit that supplies power to the motor.The transmission mechanism comprises: a motor input shaft extending along the motor axis and rotated by the motor; a motor input gear attached to the motor input shaft and rotating about the motor axis; a countershaft extending along the countershaft axis; a countershaft gear attached to the countershaft and meshing with the motor input gear, rotating about the countershaft axis; a drive gear attached to the countershaft and rotating about the countershaft axis; a ring gear meshing with the drive gear and rotating about the output shaft; and an output shaft connected to the ring gear and rotating about the output shaft. The motor axis, countershaft, and output shaft extend parallel to each other. The motor input shaft is a hollow shaft opening at both ends of the motor axis. The output shaft passes through the interior of the motor input shaft.The reduction gear axle is positioned above the motor axle with respect to the direction of gravity. The inverter unit is located directly above the motor. Viewed from the axial direction of the motor axle, at least part of the inverter unit overlaps the reduction gear. Inventive effect According to one aspect of the present invention, a motor unit is provided in which an inverter is integrated and whose size can be reduced. DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual representation of a motor unit according to one embodiment. Fig. 2 is a perspective view of a motor unit according to one embodiment. Fig. 3 is a side view of a motor unit according to one embodiment. Fig. 4 is a perspective exploded view of a motor unit according to one embodiment. Fig. 5 is a perspective exploded view of a motor unit according to one embodiment. Fig. 6 is a schematic sectional view of the motor unit. DETAILED EXECUTION The motor unit according to the embodiment of the present invention is explained below with reference to the drawings. The scope of the present invention is not limited to the following embodiments and may be arbitrarily modified within the framework of the technical concept of the present invention. In the following drawings, the scale and number of each structure may differ from the scale and number of the actual structure to make each configuration easily understandable. In the following description, the direction of gravity is defined based on the positional relationship in which a motor unit 1 is mounted on a vehicle on a horizontal road surface. The drawings further depict an XYZ coordinate system appropriately as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the direction of the Z-axis indicates the vertical direction (i.e., an up-down direction), the +Z direction is oriented upwards (towards one side opposite the direction of gravity), and the -Z direction is oriented downwards (in the direction of gravity). Therefore, in this description, when it is simply referred to as the top, it means the top with respect to the direction of gravity.The direction of the X-axis is perpendicular to the direction of the Z-axis and indicates the front-to-back orientation of the vehicle with motor unit 10, with the +X direction pointing towards the front of the vehicle and the -X direction towards the rear. The direction of the Y-axis is perpendicular to both the X-axis and Z-axis directions and represents the width (left-to-right) orientation of the vehicle, with the +Y direction pointing towards the left side of the vehicle and the -Y direction pointing towards the right side. Fig. 1 is a conceptual representation of a motor unit 10 according to one embodiment. Fig. 2 is a perspective view of the motor unit 10. Additionally, the motor axis J1, the reduction axis J3, the output axis J4, the rotation axis J6, the first central axis J7c, and the second central axis J7e, which will be described later, are virtual axes that do not actually exist. The motor unit 10 is mounted on a vehicle and propels the vehicle by turning the wheels H. The motor unit 10 is, for example, mounted on an electric vehicle (EV). Additionally, the motor unit 10 only needs to be mounted on a vehicle that uses a motor as an energy source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), and the like. As shown in Fig. 1, the motor unit 10 comprises: a motor 1, a gear mechanism (gearbox shaft) 5, a housing 6 in which the motor 1 and the gear mechanism 5 are housed, an oil pump 96, an oil cooler 97, a parking locking mechanism 7, oil O, an inverter unit 8. (Housing) The housing 6 is formed, for example, by aluminum die casting. The housing 6 is configured by connecting several components arranged in the vehicle's width direction. A storage compartment 6S is provided in the housing 6, in which the motor 1 and the transmission mechanism 5 are housed. The housing 6 holds the motor 1 and the transmission mechanism 5 in the storage compartment 6S. The storage compartment 6S is subdivided into an motor compartment 6A, in which the motor 1 is housed, and a transmission compartment 6B, in which the transmission mechanism 5 is housed. The housing 6 comprises: a motor mounting section 62, which is internally provided with a motor chamber 6A to accommodate the motor 1; a gear mounting section 63, which is internally provided with a transmission chamber 6B to accommodate the transmission mechanism 5; and a partition section 61, which divides the motor chamber 6A and the transmission chamber 6B. The partition section 61 is located axially between the motor mounting section 62 and the gear mounting section 63. An oil reservoir P for collecting the oil O is provided in a lower area of ​​the storage chamber 6S. A partition wall opening 61a is provided in the partition wall section 61, which separates the engine chamber 6A and the transmission chamber 6B. The partition wall opening 61a connects the engine chamber 6A and the transmission chamber 6B. The oil O in the storage chamber 6S moves between the engine chamber 6A and the transmission chamber 6B via the partition wall opening 61a. The storage compartment 6S contains an oil channel 90 through which oil O circulates. The oil O is supplied from the oil reservoir P to each part of the motor unit 10 in the oil channel 90. The oil channel 90 will be described in detail later. (Oil) The oil O is collected in the housing. The oil O circulates in the oil channel 90 provided in the housing 6. The oil O is used to lubricate the transmission mechanism 5 and to cool the motor 1. The oil O collects in the lower area (i.e., in the oil reservoir P) of the storage space 6S. To enable the oil O to perform the functions of lubricating and cooling oil, an oil corresponding to a low-viscosity automatic transmission fluid (ATF) is preferably used. Part of motor 1 is immersed in the oil O collected in oil reservoir P. In particular, part of the stator 32 of motor 1 is immersed in the oil O of oil reservoir P. In this way, the oil O cools the stator 32. Additionally, part of the gear mechanism 5 is immersed in the oil O of the oil reservoir P. In particular, part of the ring gear 51 of the gear mechanism 5 is immersed in the oil O of the oil reservoir P. The oil O accumulated in the oil reservoir P is lifted by the action of the ring gear 51 and diffuses into the gear chamber 6B. The oil O diffused into the gear chamber 6B is supplied to the gears of the gear mechanism 5 in the gear chamber 6B, so that the oil O spreads over the tooth surfaces of the gears. The oil O supplied to the gear mechanism 5 for lubrication drips out and is recovered in the oil reservoir P. (Oil channel) The oil channel 90 is provided in the housing 6. The oil channel 90 is configured to span the motor chamber 6A and the gearbox chamber 6B of the storage chamber 6S. The oil channel 90 is a path for supplying oil O from oil reservoir P to the motor 1 and for returning the oil O to oil reservoir P. Additionally, in this description, the "oil channel" refers to the path of the oil O circulating in storage space 6S. Therefore, the "oil channel" is a concept that encompasses not only the "flow path" that generates a steady oil flow stably directed in one direction, but also the path along which the oil temporarily remains (e.g., the oil reservoir P) and where the oil can fall off. An oil pump 96 and an oil cooler 97 are provided on the oil channel 90. In the oil channel 90, the oil O circulates in the sequence of oil reservoir P, oil pump 96, oil cooler 97 and engine 1, and returns to oil reservoir P. The oil pump 96 is located in the path of the oil channel 90 and supplies the oil O under pressure. The oil pump 96 is an electric pump driven by electrical power. The oil pump 96 is attached to the gear mounting section 63 of the housing 6. As shown in Fig. 2, the oil pump 96 is provided in the housing 6 and accommodated in the oil pump receiving bore 69. The oil pump receiving bore 69 extends axially. The oil pump receiving bore 69 opens to the left in the direction of the vehicle width (+ Y-direction). The inner circumferential surface of the oil pump receiving bore 69 has a suction opening (not shown) for drawing oil O into the oil pump 96 and an outlet opening (not shown) for supplying the oil O under pressure to the downstream side. The oil pump 96 comprises a pump motor 96m and a pump mechanism unit (not shown) driven by the pump motor 96m. The pump motor 96m is located outside the opening of the oil pump receiving bore 69. Additionally, the pump mechanism unit is housed within the oil pump receiving bore 69. The axis of rotation J6 of the pump motor 96m runs parallel to the motor axis J1. That is, the pump motor 96m rotates around the axis of rotation J6 parallel to the motor axis J1. The oil pump 96 with the pump motor 96m can be easily lengthened in the direction of the axis of rotation J6. According to this embodiment, the size of the motor unit 10 can be reduced in the radial direction of the motor axis J1 by making the axis of rotation J6 of the pump motor 96m parallel to the motor axis J1. The pump mechanism unit is, for example, a trochoidal pump in which an internal gear and an external gear mesh and rotate. In this case, the internal gear of the pump mechanism unit is turned by the pump motor 96m. The gap between the internal and external gears of the pump mechanism unit is connected to the suction and discharge ports. As shown in Fig. 1, the oil pump 96 draws oil O from the oil reservoir P via a flow path provided in the housing. The oil pump 96 delivers the drawn-in oil O to the oil cooler 97. The oil cooler 97 is located in the path of the oil channel 90 and cools the oil O that has flowed through the oil channel 90. The oil cooler 97 is attached to the gear mounting section 63 of the housing 6. The oil cooler 97 is connected to a refrigerant line 97j through which the refrigerant, cooled by a cooler (not shown), flows. The oil O flowing through the interior of the oil cooler 97 is cooled by heat exchange with the refrigerant flowing through the refrigerant line 97j. Additionally, an inverter unit 8 is located in the path of the refrigerant line 97j. That is, the inverter unit 8 and the oil cooler 97 are connected to each other by a pipe (refrigerant line 97j) that forms a refrigerant path. The refrigerant flowing through the refrigerant line 97j cools not only the oil O flowing through the oil cooler 97, but also the inverter unit 8. The oil O, which has passed through the oil cooler 97, is supplied to the motor 1 on the top of the motor chamber 6A via a flow path provided in the housing 6. The oil O supplied to the motor 1 flows from the top to the bottom along the outer circumferential surface of the motor 1 and the coil surface of the stator 32 to absorb the heat from the motor 1. This allows the entire motor 1 to be cooled. The oil O, which has cooled the motor 1, falls downwards and collects in the lower region of the motor chamber 6A. The oil O collected in the lower region of the motor chamber 6A moves via the partition opening 61a, which is provided in the partition section 61, to the gearbox chamber 6B. (Motor) Motor 1 is a motor-generator that functions both as a motor and a generator. Motor 1 primarily acts as an electric motor to propel the vehicle and as a generator during regeneration. As shown in Fig. 1, the motor 1 has a rotor 31 and a stator 32 surrounding the rotor 31. The rotor 31 can rotate about the motor axis J1. The stator 32 has a ring shape. The stator 32 surrounds the rotor 31 from the radially outer side of the motor axis J1. The rotor 31 is attached to a motor drive shaft 11, which will be described later. The rotor 31 rotates around the motor axis J1. The rotor 31 has a rotor core and a rotor magnet, which are held on the rotor core. The stator 32 has a stator core and coils. The stator core has several teeth that project inwards in the radial direction of the motor axis J1. The coil is wound onto the teeth of the stator core. Motor 1 is connected to inverter 8a. Inverter 8a converts the direct current supplied by the battery (not shown) into alternating current and supplies it to motor 1. The speed of motor 1 is controlled by controlling inverter 8a. (gear mechanism) The transmission mechanism 5 transmits the power of the motor 1 and outputs it from the output shaft 55. The transmission mechanism 5 contains several mechanisms responsible for the energy transfer between the power source and the driven device. The transmission mechanism 5 comprises: a motor drive shaft 11, a motor drive gear 21, a countershaft 13, a countershaft gear (large gear section) 23, a drive gear (small gear section) 24, a ring gear 51, an output shaft (axle) 55 and a differential device (differential gear) 50. The gears and shafts of the transmission mechanism 5 can rotate about one of the motor axis J1, the reduction axis J3, or the output axis J4. In this embodiment, the motor axis J1, the reduction axis J3, and the output axis J4 extend parallel to each other. Additionally, the motor axis J1, the reduction axis J3, and the output axis J4 are parallel to the width direction of the vehicle. In the following description, the axial direction refers to the axial direction of the motor axis J1. That is, the axial direction refers to a direction parallel to the motor axis J1 and to the width direction of the vehicle. The motor drive shaft 11 extends along the motor axis J1. The motor drive shaft 11 is attached to the rotor 31. The motor drive shaft 11 is rotated by the motor 1. A motor drive gear 21 is attached to the motor drive shaft 11. The motor drive shaft 11 extends axially with the motor axis J1 as its center point. The motor drive shaft 11 is a hollow shaft, open on both axial sides of the motor axis J1. The external shape of the motor drive shaft 11 in the axial direction is cylindrical and centered on the motor axis J1. The motor drive shaft 11 is supported by bearings to allow it to rotate about the motor axis J1. An output shaft 55 passes through the interior of the motor drive shaft 11. The motor drive gear 21 is attached to the motor drive shaft 11. The motor drive gear 21 rotates together with the motor drive shaft 11 around the motor axis J1. The countershaft 13 extends along the countershaft axis J3. The countershaft 13 rotates about the countershaft axis J3. The countershaft 13 is rotatably mounted, for example, by a bearing (not shown) of the housing and the transmission mechanism 5 via a bearing (not shown). A countershaft gear 23, a drive gear 24, and a parking lock gear 7a are attached to the countershaft 13. The countershaft gear 23 is attached to the countershaft 13. The countershaft gear 23 rotates together with the countershaft 13 around the countershaft axis J3. The countershaft gear 23 meshes with the motor drive gear 21. The drive gear 24 is attached to the countershaft 13. The drive gear 24 rotates together with the countershaft 13 and the countershaft gear 23 about the countershaft axis J3. The drive gear 24 is located axially opposite the countershaft gear 23 on the opposite side of the motor 1. The parking lock gear 7a is part of the parking lock mechanism 7. The parking lock gear 7a is attached to the countershaft 13. The parking lock gear 7a rotates together with the countershaft 13, the countershaft gear 23, and the drive gear 24 about the countershaft axis J3. The parking lock gear 7a is arranged axially between the countershaft gear 23 and the drive gear 24. The ring gear 51 is attached to the differential gear 50. The ring gear 51 rotates around the output shaft J4. The ring gear 51 meshes with the drive gear 24. The ring gear 51 transmits the power from the motor 1, transmitted via the drive gear 24, to the differential gear 50. The differential gear 50 is a device for transmitting the torque delivered by the motor 1 to the wheels H of the vehicle. The differential gear 5 has the function of transmitting the same torque to the output shafts 55 of the left and right wheels, while absorbing the speed difference between the left and right wheels H when the vehicle turns. The differential 50 has a gear housing (not shown) attached to the ring gear 51, a pair of pinions (not shown), a pinion shaft (not shown), and a pair of side gears (not shown). The gear housing rotates with the ring gear 51 about the output shaft J4. The gear housing accommodates a pair of pinions, a pinion shaft, and a pair of side gears. A pair of pinions consists of bevel gears facing each other. Two pinions are mounted on the pinion shaft. The pair of side gears consists of a bevel gear that meshes perpendicularly with a pair of pinions. Each pair of side gears is attached to the output shaft 55. The output shaft 55 rotates around the output axis J4. The motor unit 10 contains a pair of output shafts 55. Each pair of output shafts 55 is connected at one end to the side gears of the differential 50. That is, the output shaft 55 is connected to the ring gear 51 via the differential 50. The power from the motor 1 is transmitted to the output shaft 55 via the gears. Additionally, a pair of output shafts 55 protrudes from the other end to the outside of the housing 6. A wheel H is attached to the other end of the output shaft 55. The output shaft 55 transmits power outwards (via the wheels H to the road surface). In this embodiment, the output axis J4 coincides with the motor axis J1. Additionally, one of the two output shafts 55 enters the interior of the motor input shaft 11, which is a hollow shaft. Therefore, the motor unit 10 of the present embodiment can be reduced in size compared to a motor unit with a structure in which the motor axis J1 and the output axis J4 are arranged on different axes. Fig. 3 is a side view of the motor unit 10 according to one embodiment. The transmission mechanism 5 forms a power transmission path from the motor 1 to the output shaft 55. In the power transmission path of the transmission mechanism 5, the power of the motor 1 is first transmitted from the motor input gear 21 to the countershaft gear 23. The countershaft gear 23 and the input gear 24 are arranged coaxially and rotate together with the input gear 24. The power of the motor 1 is transmitted from the input gear 24 to the ring gear 51 and via the differential 50 to the output shaft 55. (The positional relationship between each axis) As shown in Fig. 3, the countershaft J3 is located above the motor shaft J1. Furthermore, since the motor shaft J1 and the output shaft J4 coincide, the countershaft J3 is positioned above the output shaft J4. According to this embodiment, the centers of the countershaft gear 23 and the drive gear 24 are displaced axially in the up-down direction relative to the centers of the motor 1 and the ring gear 51. Because the drive gear 24 and the ring gear 51 mesh, the absolute distance between them is precisely defined. By displacing the motor shaft J1 and the countershaft J3 in the up-down direction, the dimensional components of the countershaft J3 and the motor shaft J1 in the front-back direction of the vehicle can therefore be reduced. As a result, the size of the motor unit 10 in the front-to-rear direction of the vehicle can be reduced, and it can be ensured that the collision area in the vehicle is large. In this embodiment, the countershaft gear 23 and the drive gear 24 are located above the motor shaft J1. That is, the lower ends of the countershaft gear 23 and the drive gear 24 are both located above the motor shaft J1. Therefore, the drive gear 24 can be arranged such that, viewed from top to bottom, it largely overlaps the ring gear 51, and the size of the motor unit 10 in the front-to-rear direction of the vehicle can be further reduced. As shown in Fig. 3, the line segment that imaginarily connects the motor shaft J1 and the reduction shaft J3, viewed from the axial direction, is designated as the first line segment L1. The first line segment L1 forms an angle α with a vertical line VL extending in the vertical direction. The angle α is preferably within 45°. That is, the first line segment L1 preferably extends in a direction within 45° with respect to the vertical direction (the direction of gravity). As a result, the size of the motor unit 10 in the front-to-rear direction of the vehicle can be further reduced. Additionally, the angle α is more preferably within 20°. That is, the first line segment L1 preferably extends in a direction within 20° with respect to the vertical direction. As a result, the size of the motor unit 10 in the front-to-rear direction of the vehicle can be further reduced. The reduction gear J3 is located closer to the rear (-X direction) of the vehicle than the engine shaft J1. As described above, part of the ring gear 51 is immersed in the oil O of the oil reservoir P. The oil O is lifted by the ring gear 51. When the vehicle moves forward, the ring gear 51 rotates in the direction of rotation T1 shown in Fig. 3. The direction of rotation T1 is the direction in which the ring gear 51 rotates upwards at the rear of the vehicle. Therefore, the oil O lifted by the ring gear 51 is distributed more effectively at the rear of the vehicle. According to this embodiment, by positioning the reduction gear J3 closer to the rear of the vehicle than the engine shaft J1, the oil O lifted by the ring gear 51 can be efficiently supplied to the reduction gear 23 and the drive gear 24.As a result, the lubricity of the tooth surfaces of the countershaft gear 23 and the drive gear 24 can be improved, and the power transmission efficiency of the gear mechanism 5 can be improved. As shown in Fig. 3, the oil pump 96 is located above the engine axis line J1. That is, the lower end of the oil pump 96 is located above the engine axis J1. According to the present embodiment, compared to the case in which the oil pump and the engine axis J1 are arranged side by side in the front and rear directions of the vehicle, the size of the engine unit 10 in the front-to-rear direction of the vehicle can be further reduced. Consequently, the size of the engine unit 10 in the front-to-rear direction of the vehicle can be reduced, and it can be ensured that the collision area within the vehicle is large. The oil pump 96 is arranged obliquely above the front of the vehicle with respect to the engine shaft J1. In other words, the oil pump 96 is located above the engine shaft J1 and closer to the front (+X direction) of the vehicle than the engine shaft J1. As described above, the countershaft gear 23 and the drive gear 24 are located on the top of the engine shaft J1, closer to the rear (-X direction) of the vehicle than the engine shaft J1. Therefore, in the present embodiment, the oil pump 96, the countershaft gear 23, and the drive gear 24 can be displaced above the engine shaft J1 in the front-to-rear direction of the vehicle. Thus, the size of the engine unit 10 can be reduced. As described above, the oil pump 96 has the pump motor 96m, which rotates parallel to the motor axis J1 about the axis of rotation J6. As shown in Fig. 3, the line segment that imaginarily connects the motor axis J1 and the axis of rotation J6, viewed from the axial direction, is designated as the second line segment L2. The second line segment L2 forms an angle β with a vertical line VL extending in the vertical direction. The angle β is preferably within 45°. That is, the second line segment L2 preferably extends in a direction within 45° with respect to the vertical direction. As a result, the size of the motor unit 10 can be further reduced in the front-to-rear direction of the vehicle. Additionally, the angle β is more preferably within 35°. That is, the second line segment L2 preferably extends in a direction within 35° with respect to the vertical direction.As a result, the size of the motor unit 10 can be further reduced in the front-to-rear direction of the vehicle. The oil cooler 97 is located above the engine shaft J1. That is, the lower end of the oil cooler 97 is located above the engine shaft J1. According to the present embodiment, compared to a case in which the oil cooler and the engine shaft J1 are arranged side by side in the top-bottom direction of the vehicle, the size of the engine unit 10 in the front-rear direction of the vehicle can be further reduced. The oil cooler 97 is located next to the oil pump 96 above the engine shaft J1. The oil cooler 97 and the oil pump 96 are connected to each other via a flow path provided in the housing 6. By connecting the oil cooler 97 and the oil pump 96 in series, the flow path connecting them can be shortened. This shortens the flow path forming the oil channel 90 and improves the circulation efficiency of the oil O in the oil channel 90. The oil cooler 97 is located closer to the front (+ X-direction) of the vehicle than the engine axis J1. That is, the oil cooler 97 is arranged on the sloping upper surface of the front of the vehicle with respect to the engine axis J1. According to this embodiment, the oil cooler 97 can be air-cooled when the vehicle moves forward, and the cooling efficiency of the oil O by the oil cooler 97 can be improved. (Parking locking mechanism) The parking lock mechanism 7 is actuated according to the driver's gear shifting action. The parking lock mechanism 7 switches between a locked state, which restricts power transmission in the transmission mechanism 5, and an unlocked state, which removes the restriction. As shown in Fig. 3, the parking locking mechanism 7 comprises a parking locking gear 7a, a parking locking arm 7b, an arm support shaft 7e, a parking locking actuator 7c and a parking locking power transmission mechanism 7d. The parking lock gear 7a is attached to the countershaft 13. The parking lock gear 7a rotates together with the countershaft 13 about the countershaft axis J3. Several teeth are provided on the outer circumferential surface of the parking lock gear 7a, which project outwards in the radial direction of the countershaft axis J3 and are arranged in the circumferential direction of the countershaft axis J3. The parking locking arm 7b has a plate shape that extends along a plane perpendicular to the axial direction. The parking locking arm 7b is rotatably supported by an arm support shaft 7e, which is centered on a second central axis J7e extending in the axial direction. The parking locking arm 7b extends upwards from the arm support shaft 7e. The parking locking arm 7b extends along the outer circumferential surface of the parking locking gear 7a. The parking locking arm 7b faces the toothed section of the parking locking gear 7a in the radial direction of the countershaft J3. The parking locking arm 7b has a meshing section 7ba opposite the toothed section of the parking locking gear 7a. The meshing section 7ba projects towards the radial inner side of the countershaft J3. The meshing section 7ba engages with the teeth of the parking locking gear 7a. That is, the parking locking arm 7b meshes with the parking locking gear at the meshing section 7ba. The parking lock arm 7b is driven by the parking lock actuator 7c and rotates within a predetermined range about the second central axis J7e. When the parking lock mechanism 7 is locked by the driver's operation, the parking lock arm 7b rotates counterclockwise about the second central axis J7e in Fig. 3, so that the engagement section 7ba and the teeth of the parking lock gear 7a engage. This suppresses the rotation of the countershaft 13 and restricts the power transmission in the transmission mechanism 5. Conversely, when the parking lock mechanism 7 is unlocked by the driver's operation, the parking lock arm 7b rotates clockwise about the second central axis J7e, and the engagement section 7ba disengages from the toothed section of the parking lock gear 7a.As a result, the countershaft 13 can rotate freely, and the transmission mechanism 5 is in a state capable of transmitting power. According to this embodiment, the parking locking arm 7b extends in the top-bottom direction. Viewed from the axial direction, the countershaft 13 and the parking locking arm 7b are arranged side by side in the front-back direction of the vehicle. Therefore, the dimension of the motor unit 10 in the top-back direction can be reduced. In addition, a portion of the parking locking arm 7b overlaps the countershaft gear 23 in the axial direction. Thus, even though the parking locking arm 7b and the countershaft 13 are arranged side by side in the front-back direction of the vehicle, it is still possible to reduce the size of the motor unit 10 in the front-back direction of the vehicle. The parking lock force transmission mechanism 7d is located between the parking lock actuator 7c and the parking lock arm 7b. The parking lock force transmission mechanism 7d transmits the force of the manual shaft 7ca, which rotates about the first central axis J7c, to the parking lock arm 7b and rotates the parking lock arm 7b about the second central axis J7e. The parking lock actuator 7c has a manual shaft 7ca centered on a first central axis J7c extending in the up-down direction. The parking lock actuator 7c rotates the manual shaft 7ca about the first central axis J7c. The parking lock actuator 7c drives the parking lock arm 7b via the parking lock force transmission mechanism 7d. The parking lock actuator 7c is attached to the top of the housing 6. Specifically, the parking lock actuator 7c is located directly above the reduction shaft J3. That is, viewed from the top-bottom direction, the parking lock actuator 7c overlaps the reduction shaft J3. This allows the size of the motor unit 10 to be reduced in the horizontal direction. As shown in Fig. 2, the parking lock actuator 7c is attached to the outer surface of the gear receptacle 63 of the housing 6. The parking lock actuator 7c is located on the side of the gear receptacle 63 with respect to the partition section 61 of the housing 6. That is, according to the present embodiment, the parking lock actuator 7c does not overlap the partition section 61 when viewed from the top-bottom direction. To maintain the strength of the entire housing 6, the partition section 61 has a shape that projects radially from the motor axis J1 with respect to the motor 1 and the transmission mechanism 5. According to this embodiment, it is possible to suppress an enlargement of the projected area of ​​the motor unit 10 in the axial direction, since the parking locking actuator 7c and the partition section 61 do not overlap in the top-bottom direction, and to achieve a reduction in the size of the motor unit 10. As shown in Fig. 1, the parking lock gear 7a is located between the countershaft gear 23 and the drive gear 24 in the axial direction of the countershaft axis J3. According to the present embodiment, in contrast to a case where the parking lock gear is located on the opposite side of the partition section 61 with respect to the countershaft gear 23 and the drive gear 24, the parking lock gear 7a can be located close to the partition section 61. This prevents the parking lock arm 7b, which is arranged along the outer circumference of the parking lock gear 7a, from projecting towards the radially outer side of the countershaft axis J3, thereby reducing the size of the motor unit 10. (Inverter unit) As shown in Fig. 2, the inverter unit 8 comprises: the inverter 8a and the inverter housing 8b, which contains the inverter 8a. Although not shown, the inverter unit 8 also comprises a circuit board and a capacitor. Viewed from top to bottom, the inverter unit 8 has a substantially rectangular shape. The inverter unit 8 is attached to the outer surface of the housing 6. Specifically, the inverter unit 8 is attached to the outer surface of the motor mounting section 62 of the housing 6 within the inverter housing 8b. The inverter unit 8 is connected to a busbar (not shown) of the motor 1 on the top of the motor 1. The inverter unit 8 supplies the motor 1 with alternating current via the busbar. Thus, the inverter unit 8 supplies the motor 1 with electrical energy. Inverter unit 8 is located directly above motor 1. That is, inverter unit 8 is situated on top of motor 1 and overlaps it from the top-bottom direction. Consequently, compared to a scenario where inverter unit 8 is positioned at the front and rear of the vehicle relative to motor 1, the size of motor unit 10 can be reduced in both directions. This allows for a larger collision area within the vehicle. In general, the projected area of ​​the motor mounting section 62 in the axial direction is smaller than the projected area of ​​the gear mounting section 63 in the axial direction. According to this embodiment, since the inverter unit 8 is located on the radial outside of the motor mounting section 62, it is easy to arrange the inverter unit 8 and the gear mounting section 63 with axial overlap. As a result, the projected area of ​​the entire motor unit 10 in the axial direction can be reduced, and the size of the motor unit 10 can be reduced. As shown in Fig. 3, at least part of the inverter unit 8 overlaps the countershaft gear 23 when viewed from the axial direction. By overlapping the inverter unit 8 and the countershaft gear 23, the projected area of ​​the motor unit 10 can be reduced in the axial direction, and the size of the motor unit 10 can be reduced. Viewed from the axial direction, at least part of the inverter unit 8 overlaps the oil pump 96. Similarly, in the axial direction, at least part of the inverter unit 8 overlaps the oil cooler 97. By overlapping the inverter unit 8 with the oil pump 96 and the oil cooler 97, the projected area of ​​the motor unit 10 can be reduced in the axial direction, and the size of the motor unit 10 can be reduced. Figures 4 and 5 are perspective exploded views of the motor unit 10 and show the inverter unit 8 separated from the housing 6. The directions of the perspective views of the motor unit 10 differ between Figures 4 and 5. As shown in Figs. 4 and 5, the inverter unit 8 is attached to the housing 6 of the motor unit 10 by several mounting sections 40 and 45. These mounting sections 40 and 45 are divided into a first mounting section 40 (see Fig. 4) and a second mounting section 45 (see Fig. 5). The first mounting section 40 is located at the front of the vehicle with respect to the motor axis J1, and the second mounting section 45 is located at the rear of the vehicle with respect to the motor axis J1. As shown in Fig. 4, the first fastening section 40 comprises: an eaves section 42 provided on the inverter unit 8, an opposing surface 43 provided on the housing 6, and a fastening screw 41. The eaves section 42 of the first mounting section 40 projects horizontally from the outer surface of the inverter housing 8b of the inverter unit 8. The eaves section 42 is provided with a through-hole 42a that penetrates in the top-bottom direction. The opposite surface 43 of the first mounting section 40 faces the eaves section 42 in the top-bottom direction. In this embodiment, the opposite surface 43 is located on the housing 6, which is situated on the underside of the inverter unit 8. Therefore, in this embodiment, the opposite surface 43 of the first mounting section 40 faces upwards. The opposite surface 43 is provided with a threaded hole 43a that extends in the top-bottom direction and opens towards the eaves side 42 (i.e., the top). The fastening screw 41 of the first fastening section 40 is screwed through the through hole 42a of the eaves section 42 into the threaded hole 43a of the opposite surface 43. This brings the lower surface of the eaves section 42 and the opposite surface 43 into contact, and the inverter unit 8 and the housing 6 are fastened together. As shown in Fig. 5, the second fastening section 45 has: a drip edge section 47 provided on the housing 6, an opposing surface 48 provided on the inverter unit 8, and fastening screws 46. The eaves section 47 of the second mounting section 45 projects horizontally from the outer surface of the motor mounting section 62 of the housing 6. The eaves section 47 is provided with a through-hole 47a that penetrates in the top-bottom direction. The opposite surface 48 of the second mounting section 45 faces the eaves section 47 in the top-bottom direction. In this embodiment, the opposite surface 48 is located on the inverter unit 8, which is situated on the top of the housing 6. Therefore, in this embodiment, the opposite surface 48 of the second mounting section 45 faces downwards. The opposite surface 48 is provided with a threaded hole 48a that extends in the top-bottom direction and opens towards the side of the eaves section 47 (i.e., towards the underside). The fastening screw 46 of the second fastening section 45 is screwed through the through hole 47a of the eaves section 47 into the threaded hole 48a of the opposite surface 48. This brings the upper surface of the eaves section 47 and the opposite surface 48 into contact, and the inverter unit 8 and the housing 6 are fastened together. Viewed from the top-bottom direction, the first mounting section 40 and the second mounting section 45 are arranged on opposite sides of the motor shaft J1. Furthermore, the eaves sections 42 and 47 of the first mounting section 40 and the second mounting section 45 each project away from the motor shaft J1 in a vertical direction. According to this embodiment, the eaves section 42 of the first mounting section 40 and the eaves section 47 of the second mounting section 45, which are located on opposite sides of the motor shaft J1, are provided separately in the inverter unit 8 and the housing 6. Compared to the case in which all eaves sections are provided in one of the inverter unit 8 and the housing 6, the size of the motor unit 10 can therefore be reduced in the front-to-rear direction of the vehicle. Fig. 6 is a schematic cross-sectional view of the motor unit 10. In addition, the detailed structure of each part (for example, the coil of the stator 32, the rotor magnet of the rotor 31, etc.) is omitted in Fig. 6. The inverter unit 8 has a lower surface 8s opposite the housing 6. The lower surface 8s is a flat area along the horizontal direction. Viewed from the top-bottom direction, the lower surface 8s of the inverter unit 8 is surrounded by several mounting sections (the first mounting section 40 and the second mounting section 45). That is, the multiple mounting sections 40 and 45 are arranged around the lower surface 8s. As shown in Figs. 4 and 5, the outer surface of the motor mounting section 62 of the housing 6 is provided with a first rib 62a and a second rib 62b, which project radially from the motor axis J1. The first rib 62a extends along the axial direction of the motor axis J1. The first rib 62a is located directly above the motor 1. The second rib 62b extends along the circumferential direction of the motor axis J1. As shown in Fig. 6, the first rib 62a and the second rib 62b are provided with a notched surface 62s that is cut along the lower surface 8s of the inverter unit 8. That is, the notched surface 62s is provided on the outer surface of the housing 6. The notched surface 62s is a flat surface along the horizontal direction. The notched surface 62s is opposite the lower surface 8s of the inverter unit 8 in the top-bottom direction with a gap between them. The fastening screws 41 and 46 exert surface pressure on the contact surfaces of the housing 6 and the inverter unit 8 in the first fastening section 40 and the second fastening section 45. Therefore, in the first fastening section 40 and the second fastening section 45, the housing 6 and the inverter unit 8 are integrally coupled. Conversely, in the area where no surface pressure is exerted when the housing 6 and the inverter unit 8 are in contact, the vibration of the housing 6, which accompanies the operation of the motor 1 and the gear mechanism 5, is transmitted to the inverter unit 8, potentially causing it to become energized. If the inverter unit 8 becomes energized, various components of the inverter unit 8 (the inverter 8a, the circuit board, the capacitor, etc.) can be damaged.According to the present embodiment, in the area surrounded by the mounting sections 40 and 45 when viewed from the top-bottom direction, the housing 6 and the inverter unit 8 are separated in the top-bottom direction. This makes it possible to suppress the transmission of vibrations from the housing 6 to the inverter unit 8, thus preventing the inverter unit 8 from being excited. Further examples according to the present disclosure are described below: Example 1 is a motor unit attached to a vehicle to propel the vehicle, the motor unit comprising: a motor, a transmission mechanism that transmits the power of the motor and delivers it from an output shaft, a housing in which the motor and the transmission mechanism are accommodated, and an inverter unit that supplies power to the motor, wherein the transmission mechanism comprises: a motor drive shaft extending along the motor axis and rotated by the motor, a motor drive gear attached to the motor drive shaft and rotating about the motor axis, and a countershaft extending along the countershaft axis.a countershaft gear attached to the countershaft and meshing with the motor input gear, rotating about the countershaft axis; a drive gear attached to the countershaft and rotating about the countershaft axis; a ring gear meshing with the drive gear and rotating about the output shaft; and the output shaft connected to the ring gear and rotating about the output shaft, wherein the motor shaft, the countershaft axis, and the output shaft extend parallel to each other; wherein the motor input shaft is a hollow shaft opening on both sides of the motor shaft, the output shaft passing through the interior of the motor input shaft, and the countershaft being located above the motor shaft with respect to the direction of gravity; wherein the inverter unit is located directly above the motor, and, viewed from the axial direction of the motor shaft, at least a portion of the inverter unit overlaps the countershaft gear. In Example 2, the motor unit according to Example 1 may optionally further comprise: oil circulating in the oil channel provided in the housing, and an oil pump arranged in the path of the oil channel and supplying the oil under pressure, wherein, viewed from the axial direction of the motor axis, at least a part of the inverter unit overlaps the oil pump. In Example 3, the motor unit according to Example 1 or 2 may optionally further comprise: oil circulating in the oil channel provided in the housing, and an oil cooler arranged in the path of the oil channel to cool the oil, wherein, viewed from the axial direction of the motor axis, at least a part of the inverter unit overlaps the oil cooler. In Example 4, the motor unit according to Example 3 can optionally further include the inverter unit and the oil cooler being connected by a pipe that forms a refrigerant path. In Example 5, the motor unit according to one of Examples 1 to 4 may optionally further include the inverter unit having a lower surface opposite the housing, wherein the inverter unit is attached to the housing by several mounting sections arranged on the lower surface, wherein a notched surface is provided along the lower surface of the inverter unit, wherein the lower surface of the inverter unit is opposite in the top-bottom direction with a gap between it. In Example 6, the motor unit according to Example 5 may optionally further include the mounting section having: a flange section provided on one side of the housing and the inverter unit and projecting in a horizontal direction; an opposing surface provided on the other side of the housing and the inverter unit and facing the flange section in the top-bottom direction; and a mounting screw, wherein the flange section is provided with a through-hole penetrating in the top-bottom direction, wherein a threaded hole is provided on the opposing surface, and wherein the mounting screw is screwed through the through-hole of the flange section into the threaded hole of the opposing surface. In Example 7, the motor unit according to Example 6 can optionally further have the multiple mounting sections divided into a first mounting section and a second mounting section, wherein in the first mounting section the eaves section is provided on the inverter unit, and the opposite surface is provided on the housing, wherein in the second mounting section the eaves section is provided on the housing, and the opposite surface is provided on the inverter unit, wherein, viewed from the top-bottom direction, the first mounting section and the second mounting section are arranged on opposite sides with respect to the motor axis, wherein, viewed from the top-bottom direction, the eaves section of the first mounting section and the second mounting section each project in a direction away from the motor axis. Although embodiments of this invention have been described above, each structure in the embodiment and combinations thereof, etc., are examples, and additions, omissions, substitutions, and other modifications to the structure can be made without altering the meaning of this invention. The present invention is not limited to the embodiments described above. Reference symbol list 1: Motor; 5: Gear mechanism; 6: Housing; 7: Parking lock mechanism; 7a: Parking lock gear; 7b: Parking lock arm; 7c: Parking lock actuator; 8: Inverter unit; 8a: Inverter; 8s: Lower surface; 10: Motor unit; 11: Motor drive shaft; 13: Countershaft; 21: Motor drive gear; 23: Countershaft gear; 24: Drive gear; 40: First mounting section (fixed part); 45: Second mounting section (fixed part); 41, 46: Mounting screw; 42, 47: Eaves section; 42a, 47a: Through hole; 43, 48: Opposite surface; 43a, 48a: Threaded hole; 51: Ring gear; 55: Output shaft; 61: Partition section; 62: Motor mounting section; 62s: Notched surface; 63: Gear mounting section; 90: Oil channel; 96: Oil pump; 96m: Pump motor; 97: Oil cooler; J1: Motor shaft; J3: Countershaft; J4: Output shaft; J6: Rotary shaft; L1: First line segment; L2: Second line segment; O: Oil; P: Oil reservoir.

Claims

A motor unit attached to a vehicle to propel the vehicle, comprising: a motor having a rotor and stator rotatable about a motor axis as its center; a transmission mechanism transmitting the power of the motor and delivering it from an output shaft; a housing having a motor mounting section for receiving the motor and a gear mounting section for receiving the transmission mechanism; an inverter unit supplying power to the motor; and an oil cooler provided in the path of an oil channel for cooling the oil, wherein the oil cooler is attached to an outer surface of the housing and, viewed from the axial direction of the motor axis, at least a portion of the inverter unit overlaps the oil cooler; the transmission mechanism having a gear that, viewed from the axial direction of the motor axis, overlaps with at least a portion of the inverter unit.and at least part of the oil cooler is positioned further than the gear on one side in a direction that is orthogonal to both the up-down direction and the axial direction of the engine axis. A motor unit fitted to a vehicle to propel the vehicle, comprising: a motor having a rotor and stator rotatable about a motor axis as its center, a transmission mechanism transmitting the power of the motor and delivering it from an output shaft, a housing having a motor receiving section for the motor and a gear receiving section for the transmission mechanism, an inverter unit supplying power to the motor, and an oil cooler provided in the way of an oil channel for cooling the oil, the oil cooler being attached to an outer surface of the housing and, viewed from the axial direction of the motor axis, at least a portion of the inverter unit overlapping the oil cooler. Motor unit according to claim 2, wherein the transmission mechanism has a gear that overlaps the inverter unit in the axial direction of the motor axis. Motor unit according to claim 3, wherein at least a part of the oil cooler is arranged further than the gear on one side of a direction that is orthogonal to both the axial direction of the motor axis and the top-bottom direction. Motor unit according to claim 1 or 4, wherein one side of the direction which is orthogonal to both the axial direction of the motor axis and the top-bottom direction is the front of the vehicle in the front-back direction of the vehicle. Motor unit according to one of claims 1 to 5, wherein the oil cooler is attached to a radially outer surface of the housing. Motor unit according to claim 6, wherein the oil cooler is attached to a radially outer surface of the gear mounting section. Motor unit according to one of claims 1 to 7, wherein the inverter unit is attached to the housing in a mounting section, the mounting section comprising: a fascia section provided on one side of the housing and the inverter unit and projecting along the horizontal direction, an opposite surface provided on the other side of the housing and the inverter unit and facing the fascia section in the top-bottom direction, and a mounting screw, wherein a through-hole penetrating in the top-bottom direction is provided on the fascia section, a threaded hole is provided on the opposite surface, and the mounting screw is screwed through the through-hole of the fascia section into the threaded hole of the opposite surface. A motor unit attached to a vehicle to propel the vehicle, comprising: a motor having a rotor and stator rotatable about a motor axis as its center; a transmission mechanism transmitting the power of the motor and delivering it from an output shaft; a housing having a motor receiving section for receiving the motor and a gear receiving section for receiving the transmission mechanism; an inverter unit supplying power to the motor; and an oil cooler provided in the path of an oil channel for cooling the oil, wherein, viewed from the axial direction of the motor axis, at least a portion of the inverter unit overlaps the oil cooler; the inverter unit is attached to the housing in a mounting section, the mounting section having: a fascia section provided on one side of the housing and the inverter unit, projecting along the horizontal direction;a opposite surface provided on the other side of the housing and inverter unit and facing the eaves section in the top-bottom direction, and a fastening screw, wherein a through hole penetrating in the top-bottom direction is provided on the eaves section, a threaded hole is provided on the opposite surface, and the fastening screw is screwed through the through hole of the eaves section into the threaded hole of the opposite surface. Motor unit according to claim 8 or 9, wherein the mounting section comprises a first mounting section and a second mounting section, wherein in the first mounting section the eaves section is provided on the inverter unit and the opposite surface is provided on the housing, wherein in the second mounting section the eaves section is provided on the housing and the opposite surface is provided on the inverter unit. Motor unit according to claim 8 or 9, wherein the fastening section comprises a first fastening section and a second fastening section, wherein, viewed from the axial direction of the motor axis, the first fastening section is positioned on the side opposite the second fastening section, clamping around the motor axis. Motor unit according to one of claims 1 to 11, wherein the oil cooler is positioned further than the motor shaft on the top side. Motor unit according to one of claims 1 to 12, wherein the inverter unit and the oil cooler are connected to each other by a line that forms a refrigerant path. Motor unit according to one of claims 1 to 13, wherein the inverter unit has a lower surface opposite the housing, wherein the housing is opposite the lower surface in the top-bottom direction with a gap between them. Motor unit according to one of claims 1 to 14, wherein the motor receiving section has an internal motor chamber, wherein the housing has a flow channel, wherein oil that has passed through the oil cooler is supplied to the motor via the flow channel on the top of the motor chamber.

Images