Motor unit

Abstract

A motor unit is provided with: an electric motor (10) having a rotor (11), a stator (12), and a housing (13) that accommodates the rotor (11) and the stator (12) therein, has an oil passage (61) through which cooling oil flows and outflow passages (71-74) through which the cooling oil flows from the oil passage (61) to the stator (12) formed in the upper part thereof, and has a reservoir (81) for the cooling oil in the lower part thereof; a speed reducer (20) having a speed reduction mechanism (22) comprising a plurality of gears (22a, 22b), and a gear housing (23), the gear housing (23) housing the speed reduction mechanism (22) therein and having a coolant oil reservoir (82) communicating with the reservoir (81) of the housing (13) at the lower part, the other end surface of the speed reducer (20) having one end surface of the motor (10) attached thereto, the speed reducer (20) reducing and transmitting the number of rotations of the motor (10); an oil pump (30) that is attached to one end surface of the speed reducer (20), sucks up the cooling oil stored in the storage section (82) of the gear housing (23), and circulates the cooling oil through an oil passage (61) of the housing (13); and an oil cooler (40) which is attached to one end surface of the speed reducer (20), has an inflow port (40a) connected to an outflow port (30b) for cooling oil of the oil pump (30), cools the cooling oil from the outflow port (30b) of the oil pump (30), and causes the cooled cooling oil to flow from the outflow port (40b) into a cooling oil flow path between the outflow port (40b) and the inflow port of the oil path (61) of the housing (13).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a motor unit including a motor and a reduction gear. BACKGROUND

[0002] A motor unit shown in Patent Literature 1 is used for a power transmission system of an electric vehicle (EV) or the like, and includes a motor and a reduction gear.

[0003] The motor unit shown in Patent Literature 1 is as shown below.

[0004] That is, a housing has an accommodation space inside, and the accommodation space has a motor chamber that accommodates a motor and a gear chamber that accommodates a gear portion having a reduction device and a differential device, in a manner extending in a horizontal direction.

[0005] An oil accumulation portion is located on the lower side of the gear chamber.

[0006] Oil accumulated in the oil accumulation portion is raised by the action of the differential device, and a part of the oil is diffused in the gear chamber and spreads to the tooth surfaces of each gear of the reduction device and the differential device, and is recovered to the oil accumulation portion after dripping down.

[0007] Further, the oil accumulated in the oil accumulation portion is introduced into the inside of the rotor by being raised by the differential device, and is diffused to the stator uniformly under the action of centrifugal force accompanying the rotation of the rotor and cools the stator, and is accumulated in the lower region in the motor chamber after dripping down to the lower side, and moves to the gear chamber.

[0008] The oil accumulated in the oil accumulation portion is pumped up and cooled by a cooler, and then is raised to the upper side of the motor to be supplied to the motor, takes heat from the stator while flowing along the outer peripheral surface of the stator, thereby cooling the motor, and the oil after flowing along the outer peripheral surface of the stator drips down to the lower side to be accumulated in the lower region in the motor chamber, and moves to the gear chamber.

[0009] The pump is disposed on the lower side of the motor chamber.

[0010] The cooler is disposed on the lower side in the plumb direction of the motor chamber, and a contact surface of the cooler and the first side wall surface at least partially overlap each other in the axial direction.

[0011] The inverter unit is fixed to the outer peripheral surface of the motor accommodation portion toward the radially outer side.

[0012] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: WO 2019 / 131417 SUMMARY

[0013] PROBLEMS TO BE SOLVED BY THE INVENTION In the motor unit shown in Patent Document 1, since the pump is located on the lower side of the motor chamber and the cooler is located on the lower side of the motor chamber in the vertical direction, there is a technical problem that the weight balance is biased to one side of the motor chamber.

[0014] Furthermore, since the contact surface of the cooler overlaps with the first side wall, the cooler is directly affected by the heat generated by the motor, which may reduce the cooling performance of the cooler on the oil.

[0015] This disclosure is made in view of the above points, and its purpose is to provide a motor unit in which weight balance deviation is less and cooling performance degradation of the cooler is suppressed in a motor unit including an electric motor and a reducer.

[0016] Technical solutions adopted to solve technical problems The motor unit disclosed herein includes an electric motor, a speed reducer, an oil pump, and an oil cooler. The electric motor has a rotor, a stator, and a housing. The housing houses the rotor and stator internally, and has an oil passage for cooling oil flow and an outlet passage for cooling oil to flow from the oil passage to the stator in its upper part. It also has a cooling oil storage section in its lower part. The speed reducer has a reduction mechanism composed of multiple gears and a gear housing internally housing the reduction mechanism and having a cooling oil storage section in its lower part communicating with the storage section of the housing. One end face of the electric motor is mounted on the other end face of the speed reducer to reduce and transmit the rotational speed of the electric motor. The oil pump is mounted on one end face of the speed reducer, drawing up cooling oil accumulated in the storage section of the gear housing and circulating the cooling oil in the oil passage of the housing. The oil cooler is mounted on one end face of the speed reducer, with its inlet connected to the cooling oil outlet of the oil pump. It cools the cooling oil from the outlet of the oil pump and allows the cooled oil to flow from the outlet into the cooling oil flow path between the outlet and the inlet of the oil passage of the housing.

[0017] Invention Effects According to this disclosure, it is possible to reduce the deviation of weight balance in the motor unit and suppress the reduction of cooling performance of the cooler. Attached Figure Description

[0018] Figure 1 This is a perspective view showing the appearance of the motor unit in Embodiment 1.

[0019] Figure 2 This is a side view showing the appearance of the motor unit in Embodiment 1.

[0020] Figure 3 This is a perspective sectional view showing the main parts of the motor unit in Embodiment 1.

[0021] Figure 4 yes Figure 2 BB cross-sectional view.

[0022] Figure 5 This is a diagram showing the motor unit of Embodiment 2, corresponding to a BB cross-section. Detailed Implementation

[0023] Implementation method 1. use Figures 1 to 4 The motor unit of Embodiment 1 will be described.

[0024] The motor unit of Embodiment 1 is a motor unit for installation in the power transmission system of electric vehicles (EVs) and includes an electric motor 10 and a reducer 20.

[0025] The motor unit in Embodiment 1 includes an electric motor 10, a speed reducer 20, an oil pump 30, an oil cooler 40, and an inverter unit 50.

[0026] In addition, Figures 1 to 4 In the XYZ coordinate system, the X-axis direction represents the front-to-back direction of the vehicle equipped with the motor unit, the Y-axis direction represents the left-to-right direction of the vehicle, and the Z-axis direction represents the vertical direction.

[0027] In this example, the electric motor 10 generates power for driving the electric vehicle and generates braking force through regenerative braking during deceleration.

[0028] like Figure 3 as well as Figure 4 As shown, the electric motor 10 has a rotor 11, a stator 12, a housing 13, a front bearing 14, and a rear bearing 15.

[0029] The rotor 11 rotates around a rotation axis that extends in the horizontal direction (Y-axis in this example).

[0030] The rotor 11 has a rotating shaft (shaft) 11a, a rotor core 11b and a rotor magnet (not shown), and is housed inside the housing 13.

[0031] One end of the rotating shaft 11a is supported by the front bearing 14 and can rotate freely, while the other end is supported by the rear bearing 15 and can rotate freely, and rotates around the rotation axis.

[0032] The rotor core 11b is constructed by laminating silicon steel sheets. The rotor core 11b is an axially extending cylinder fixed at its center to the rotating shaft 11a. Multiple rotor magnets are fixed to the rotor core 11b. These multiple rotor magnets are arranged circumferentially with alternating magnetic poles.

[0033] The stator 12 is located radially outside the rotor 11, housed inside the housing 13 and held within the housing 13.

[0034] The stator 12 has a stator core and coils. The coils of the stator 12 are electrically connected to the inverter unit 50 via bus bars.

[0035] The coils of the stator 12 have a front coil end 12a protruding from one end of the stator core toward the one end surface side of the motor 10 in the axial direction, and a rear coil end 12b protruding from the other end of the stator core toward the other end surface side of the motor 10 in the axial direction.

[0036] When electric power is supplied to the stator 12, the rotor 11 rotates about the rotational axis as a center.

[0037] The rotor 11 and the stator 12 constitute a publicly known internal rotor type motor.

[0038] The housing 13 houses the rotor 11 and the stator 12 inside.

[0039] The housing 13 has a main body 13a and a front cover 13b.

[0040] The main body 13a is a bottomed cylindrical body with one end open. In the present example, the open side is referred to as the front, and also as the one end surface, and the bottom side is referred to as the rear, and also as the other end surface.

[0041] The main body 13a has a support portion that supports the rear bearing 15 on the inner side of the center of the bottom.

[0042] The front cover 13b covers the one end opening of the main body 13a, and has a through hole in the center portion thereof through which the one end portion of the rotational shaft 11a of the rotor 11 is inserted.

[0043] The front cover 13b has a support portion that supports the front bearing 14 in the through hole thereof.

[0044] In the rotational shaft 11a, the one end portion is supported by the front bearing 14 so as to be freely rotatable, and the other end portion is supported by the rear bearing 15 so as to be freely rotatable.

[0045] As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12. Figure 3 As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12. Figure 4 As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12.

[0046] The cooling oil has the functions of a lubricating oil and a cooling oil, and a lubricating oil for automatic transmissions or the like having a low viscosity is preferably used.

[0047] As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12. Figure 3 As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12. Figure 4 As shown in Figs. 1 and 2, the motor 10 has a housing 13, a rotor 11, and a stator 12.

[0048] The outflow path 71 is an outflow path for the front coil end, which is provided branching from the first oil path 61 on the flow inlet side of the first oil path 61, for spraying the cooling oil flowing in the first oil path 61 toward the front coil end 12a.

[0049] The cooling oil sprayed from the outflow path 71 toward the front coil end 12a cools the front coil end 12a.

[0050] The cooling oil sprayed toward the front coil end 12a flows along the outer peripheral surface of the front coil end 12a and drips toward the reservoir 81.

[0051] The outflow path 72 is an outflow path for the rear coil end, which is provided branching from the first oil path 61 on the side opposite the flow inlet of the first oil path 61, that is, on the other end surface side of the motor 10, for spraying the cooling oil flowing in the first oil path 61 toward the rear coil end 12b.

[0052] The cooling oil sprayed from the outflow path 72 toward the rear coil end 12b cools the rear coil end 12b.

[0053] The cooling oil sprayed toward the rear coil end 12b flows along the outer peripheral surface of the rear coil end 12b and drips toward the reservoir 81.

[0054] The outflow paths 73, 74 for the cooling oil to flow out from the oil path 61 toward the front bearing 14 and the rear bearing 15 are formed in the upper portion of the main body 13a of the housing 13.

[0055] The outflow path 73 is an outflow path for the front bearing, which is provided branching from the first oil path 61 on the flow inlet side of the first oil path 61 and on the side of the one end surface of the motor 10 than the outflow path 71 for the front coil end, for spraying the cooling oil flowing in the first oil path 61 toward the front bearing 14.

[0056] The cooling oil sprayed from the outflow path 73 toward the front bearing 14 lubricates the front bearing 14 and drips toward the reservoir 81 after the lubrication.

[0057] The outflow path 74 is an outflow path for the rear bearing, which is provided branching from the first oil path 61 on the side opposite the flow inlet side of the first oil path 61, that is, on the other end surface side of the motor 10 than the outflow path 72 for the rear coil end, for spraying the cooling oil flowing in the first oil path 61 toward the rear bearing 15.

[0058] The cooling oil sprayed from the outflow path 74 toward the rear bearing 15 lubricates the rear bearing 15 and drips toward the reservoir 81 after the lubrication.

[0059] The reservoir 81 of the cooling oil is provided in the lower portion of the housing 13.

[0060] The reservoir 81 is an oil pan.

[0061] The bottom surface of the reservoir 81 is formed to have a slope that gradually decreases toward the one end surface side of the motor 10, so that the stored cooling oil flows toward the one end surface side of the motor 10.

[0062] The cooling oil after cooling the stator 12 and the cooling oil after lubricating the bearings 14, 15 are dropped and recovered to the reservoir 81.

[0063] The speed reducer 20 reduces the number of rotations of the motor 10 in this case and transmits it to the drive wheels (drive shafts, not shown) of the electric vehicle.

[0064] The one end surface of the motor 10 is contact-installed to the other end surface of the speed reducer 20, and the motor 10 and the speed reducer 20 are installed side by side in the horizontal direction (in this case, the Y-axis direction).

[0065] The one end surface of the motor 10 is bisected along the vertical line (in this case, the Z-axis), one of which is a contact surface including the insertion hole (in this case, the insertion hole of the front cover 13b) of the housing 13 through which the one end portion of the rotating shaft 11a is inserted, and the other of which is a non-contact surface, and the contact surface in the one end surface of the motor 10 contacts the contact surface in the other end surface of the speed reducer 20, so that the motor 10 is installed to the speed reducer 20.

[0066] The non-contact surface in the one end surface of the motor 10, that is, the non-contact surface in the one end surface of the front cover 13b is an exposed surface.

[0067] As shown in Figs. 1 and 2, the motor 10 includes a rotating shaft 11, a stator 12, a housing 13, a pair of bearings 14, 15, and a pair of oil reservoirs 81, 82. Figure 3 and Figure 4 As shown in Figs. 1 and 2, the motor 10 includes a rotating shaft 11, a stator 12, a housing 13, a pair of bearings 14, 15, and a pair of oil reservoirs 81, 82.

[0068] The gear rotating shaft 21 is coaxial with the rotating shaft 11a of the motor 10, and the other end surface thereof is connected to the one end surface of the rotating shaft 11, and the one end portion thereof is supported by the gear bearing 24 to be freely rotatable, and the other end portion thereof is supported by the gear bearing 25 to be freely rotatable, and the gear rotating shaft 21 transmits the rotational force of the rotating shaft 11a to rotate around the rotating shaft center.

[0069] In addition, the gear rotating shaft 21 can be formed integrally with the rotating shaft 11a.

[0070] The speed reduction mechanism 22 is configured of a plurality of gears, and reduces the number of rotations transmitted to the gear rotating shaft 21 via the rotating shaft 11a of the motor 10 and transmits it to the drive wheels (drive shafts).

[0071] The reduction mechanism 22 includes: a gear 22a fixed to the gear rotation shaft 21; a plurality of gears 22b and 22c that reduce and transmit the rotation of the gear 22a according to the gear ratio; and a gear rotation shaft for the plurality of gears 22b and 22c, each supported on a pair of bearings.

[0072] Multiple gears 22b and 22c mesh with each other in the X-axis direction.

[0073] The gear housing 23 houses the reduction mechanism 22 inside.

[0074] The gear housing 23 has a first gear housing 23a and a second gear housing 23b.

[0075] The first gear housing 23a is a bottomed cylindrical body with one open end.

[0076] The first gear housing 23a has a planar opening with one end face as the plane, the other end face as the bottom face, and the remaining faces as the left side, right side, front, and back sides. The bottom face has a flat plate with an insertion hole that communicates with the insertion hole of the front cover 13b. The front and back faces have parallel flat plates, the left side has a semi-circular curved plate, and the right side has a flat plate.

[0077] The first gear housing 23a has a thick-walled portion 23a1 extending from the bottom and right side on the upper part of the right side face.

[0078] The inner surface of the thick-walled section is arc-shaped to avoid hindering the rotation of gears 22b, etc.

[0079] The other end face of the first gear housing 23a has: a contact surface that contacts a contact surface in one end face of the motor 10 including the through hole; and a contact surface located at... Figure 2 The non-contact surface on the left side of the diagram.

[0080] The bottom inner side of the first gear housing 23a has: a support portion for supporting the gear bearing 25; and multiple support portions for supporting the gear bearing, which provides shaft support to the other end of the gear rotation shaft for the multiple gears 22b, 22c.

[0081] The second gear housing 23b is made of a flat plate that covers one end opening of the first gear housing 23a and has the same outer diameter shape as the front of the first gear housing 23a.

[0082] The inner surface of the second gear housing 23b has: a support portion for supporting the gear bearing 24; and multiple support portions for supporting the gear bearing, which provides shaft support to the other end of the gear rotation shaft for the multiple gears 22b, 22c.

[0083] like Figure 3 as well as Figure 4 As shown, the upper part of the gear housing 23 (in this example, the upper part of the thick-walled portion 23a1 of the first gear housing 23a) has an oil passage 62 (second oil passage) that is parallel to the Y-axis and supplies cooling oil in a straight line.

[0084] At the other end face of the reducer 20 and one end face of the motor 10, the outlet of the cooling oil in the second oil passage 62 is connected to the inlet of the cooling oil in the first oil passage 61.

[0085] The motor 10 is mounted to the reducer 20 by contacting the contact surface in one end face of the motor 10 with the contact surface in the other end face of the reducer 20, and the second oil circuit 62 is directly connected to the first oil circuit 61.

[0086] The lower part of the gear housing 23 (the lower part of the first gear housing 23a in this example) has a storage section 82 for cooling oil.

[0087] Storage section 82 is an oil pan.

[0088] The storage section 82 is connected to the storage section 81 of the outer casing 13 at the contact surface between the other end face of the gear housing 23 and the one end face of the motor 10.

[0089] Cooling oil stored in storage section 81 flows into storage section 82 and is stored in storage section 82.

[0090] Among the multiple gears 22b and 22c of the reduction mechanism 22, at least the outer periphery of the gear 22c with the largest diameter is immersed in the cooling oil 83 stored in the storage section 82.

[0091] By rotating gear 22a and multiple gears 22b and 22c of the reduction mechanism 22, the large-diameter gear 22c, whose outer periphery is immersed in the cooling oil 83, splashes the cooling oil 83.

[0092] The cooling oil, kicked up by the large-diameter gear 22c, spreads within the gear housing 23, lubricating the gear bearings 24, 25, etc., and then drips into the storage section 82 after lubrication.

[0093] The oil pump 30 is installed on one end face of the reducer 20.

[0094] When viewed from the oil pump 30 side towards the motor 10 side, i.e. Figure 2 As shown from Figure 1 In the planar side perspective view shown by arrow A in the figure, the oil pump 30 is installed in one end face of the motor 10 and in the lower end face of the reducer 20 (in this example, the end face of the second gear housing 23b).

[0095] The oil pump 30 is installed on the side of the reducer 20 opposite to the motor 10, across the reducer 20.

[0096] like Figure 3 as well as Figure 4 As shown, at least a portion of the cooling oil inlet 30a of the oil pump 30 is immersed in the oil pan constituting the storage section 82 at a position below the rotation axis of the gear rotation shaft 21 of the reducer 20.

[0097] The oil pump 30 draws up the cooling oil accumulated in the storage section 82 of the gear housing 23 and circulates the cooling oil in the first oil passage 61 formed in the upper part of the outer casing 13.

[0098] The oil cooler 40 is installed on one end face of the reducer 20.

[0099] When viewed from the oil cooler 40 side towards the motor 10 side, i.e. Figure 2 As shown in the planar side perspective view, the oil cooler 40 is installed inside one end face of the motor 10 and is installed on one end face of the reducer 20 (in this example, one end face of the second gear housing 23b) located above the oil pump 30 and below the second oil passage 62 formed on the upper part of the gear housing 23.

[0100] The oil cooler 40 is installed on the side of the reducer 20 opposite to the motor 10, across the reducer 20.

[0101] As described above, since the motor 10 is mounted on the other end face of the reducer 20 in a manner that separates it from the reducer 20, and the oil pump 30 and oil cooler 40 are mounted on one end face of the reducer 20, the deviation in the weight balance of the motor unit is suppressed.

[0102] Furthermore, since the oil cooler 40 is installed on the end face of the reducer 20 opposite to the motor 10, separated from the reducer 20, the oil cooler 40 is not directly heated by the heat generated by the motor 10 and is less affected by the heat generated by the motor 10, thus suppressing the reduction of the cooling performance of the oil cooler 40.

[0103] Furthermore, since the gear housing 23 adopts a structure having a first gear housing 23a and a second gear housing 23b, and the oil pump 30 and the oil cooler 40 are installed on the other end face of the second gear housing 23b, the oil pump 30 and the oil cooler 40 used for oil cooling can be treated as a component installed on the second gear housing 23b, thus improving assemblability.

[0104] like Figure 3 As shown, the cooling oil inlet 40a of the oil cooler 40 is connected to the cooling oil outlet 30b of the oil pump 30 via the third oil passage 63.

[0105] like Figure 4 As shown, the third oil passage 63 is formed inside the second gear housing 23b in such a way that the cooling oil outlet 30b of the oil pump 30 is directly connected to the cooling oil inlet 40a of the oil cooler 40.

[0106] The third oil passage 63 is integrally formed on the other end face of the second gear housing 23b by means of casting of the core, etc.

[0107] Alternatively, the third oil passage 63 can also be formed by mounting other components, such as molded parts or machined parts, to the other end face of the flat second gear housing 23b.

[0108] The oil cooler 40 cools the cooling oil from the outlet 30b of the oil pump 30 and flows the cooled oil from the outlet 40b into the cooling oil flow path formed on the upper part of the housing 13 between the outlet 40b and the inlet of the first oil passage 61.

[0109] The cooling oil outlet 40b of the oil cooler 40 is connected to the cooling oil inlet of the second oil passage 62, which is formed on the upper part of the thick-walled portion 23a1 of the gear housing 23, via the fourth oil passage 64.

[0110] The fourth oil passage 64 is configured to directly connect the cooling oil outlet 40b of the oil cooler 40 to the cooling oil inlet of the second oil passage 62.

[0111] The fourth oil passage 64 is formed parallel and straight to the Z-axis on one end face of the thick-walled portion 23a1 of the gear housing 23, and its inlet is bent toward one end face and connected to the outlet 40b of the cooling oil.

[0112] Furthermore, the outlet of the fourth oil passage 64 and the inlet of the second oil passage 62 are not physically present, but are used virtually for the sake of explanation. The fourth oil passage 64 and the second oil passage 62 are formed as one unit.

[0113] That is, when the first gear housing 23a constituting the gear housing 23 is manufactured using a mold or the like, the groove formed on the thick-walled portion 23a1 by pulling out the mold is covered by the second gear housing 23b, thereby forming a connected fourth oil passage 64 and a second oil passage 62.

[0114] Alternatively, a thick-walled portion 23a1, which forms a groove connecting the outlet 40b of the cooling oil of the oil cooler 40 to the inlet of the first oil passage 61, can be used as another component.

[0115] In this case, in the first gear housing 23a which has a thick-walled portion 23a1 as another component, a fourth oil passage 64 and a second oil passage 62 are formed and connected by a groove formed in the thick-walled portion 23a1 covered by a second gear housing 23b.

[0116] Therefore, the flow path of the cooling oil from the outlet 40b of the oil cooler 40 to the inlet of the first oil passage 61 is composed of the fourth oil passage 64 and the second oil passage 62.

[0117] The oil cooler 40 is cooled by a radiator (not shown), and the cooling water that has cooled the inverter unit 50 flows in from the cooling water inlet 40c. The cooling water and the cooling oil exchange heat, thereby cooling the oil. The cooled water after heat exchange flows out from the cooling water outlet 40d.

[0118] That is, in the oil cooler 40, the cooling oil passing through the oil cooler 40 exchanges heat with the cooling water and is cooled.

[0119] The oil cooler 40 can use a known heat exchanger that cools the cooling oil with refrigerant.

[0120] In addition, the refrigerant that exchanges heat with the cooling oil is not limited to cooling water, but can also be other known refrigerants.

[0121] The oil pump 30 draws up the cooling oil accumulated in the storage section 82 of the gear housing 23 from the oil pump 30's cooling oil inlet 30a. The drawn-up cooling oil flows from the oil pump 30's cooling oil outlet 30b through the third oil passage 63 into the oil cooler 40's cooling oil inlet 40a, and flows out from the oil cooler 40's cooling oil outlet 40b after being cooled by the oil cooler 40.

[0122] Cooling oil flowing out of the outlet 40b of the oil cooler 40 flows into the inlet of the first oil passage 61 via the fourth oil passage 64 and the second oil passage 62.

[0123] Cooling oil flowing into the inlet of the first oil passage 61 is sprayed from the upper part of the housing 13 into the interior through the outlet 71 of the front coil end, the outlet 72 of the rear coil end, the outlet 73 of the front bearing, and the outlet 74 of the rear bearing.

[0124] Cooling oil sprayed from the upper part of the outer casing 13 cools the front coil end 12a and the rear coil end 12b of the stator 12 coil, lubricates the front bearing 14 and the rear bearing 15, and is recycled to the storage section 81.

[0125] That is, the cooling oil flows from the storage section 82 of the gear housing 23 through the oil pump 30, the third oil passage 63, the oil cooler 40, the fourth oil passage 64, the second oil passage 62, the first oil passage 61, the outlet passage 71 to the outlet passage 74, the stator, the bearing 14 and the bearing 15, and the storage section 81, and then circulates back to the storage section 82.

[0126] Since the oil pump 30 is installed at the lower part of the other end face of the reducer 20, at least a part of the cooling oil inlet 30a of the oil pump 30 must be located below the oil level of the cooling oil stored in the storage part 82 of the gear housing 23. Therefore, it is possible to prevent insufficient suction of cooling oil by the oil pump 30 and to ensure smooth circulation of cooling oil.

[0127] The inverter unit 50 converts DC current into AC current to drive and control the motor 10 during driving, and converts the AC current from the motor 10 into DC current to recover energy during deceleration (regeneration).

[0128] like Figure 1 as well as Figure 2 As shown, one side of the inverter unit 50 is opposite to the non-contact surface of one end face of the motor 10. The bottom surface of the inverter unit 50 is mounted on one side of the reducer 20. This side is the flat surface of the right side shown in the figure, and in this example, it is mounted on one side of the first gear housing 23a.

[0129] Furthermore, a portion of the bottom surface of the inverter unit 50 (in this example, a portion of the bottom surface protruding from one side of the reducer 20 along the axis of rotation) is opposite to one side of the oil pump 30 and one side of the oil cooler 40.

[0130] The inverter unit 50 is disposed in the space in the direction of the rotation axis of the non-contact surface in one end face of the motor 10, that is, in a cylindrical space with the non-contact surface in one end face of the motor 10 and one side of the reducer 20 as two adjacent sides.

[0131] As a result, the space formed by the electric motor 10 and the reducer 20 is effectively utilized, thereby enabling miniaturization of the external dimensions of the motor unit.

[0132] Furthermore, the oil pump 30 and the oil cooler 40 are arranged in a cylindrical space with the other end face of the reducer 20 and a portion of the bottom surface of the inverter unit 50 as two adjacent sides.

[0133] As a result, the space formed by the reducer 20 and the inverter unit 50 is effectively utilized, thereby enabling miniaturization of the external dimensions of the motor unit.

[0134] The inverter unit 50 is cooled by cooling water, which exchanges heat with the cooling oil passing through the oil cooler 40 to cool the cooling oil.

[0135] The cooling water used to cool the inverter unit 50 is the cooling water after the radiator has cooled it. After cooling the inverter unit 50, it flows into the oil cooler 40 from the cooling water inlet 40c.

[0136] As described above, the motor unit of Embodiment 1 is based on a motor unit including an electric motor 10 and a reducer 20, with an oil pump 30 and an oil cooler 40 installed on an end face opposite to the end face on which the electric motor 10 is mounted. Therefore, the deviation in the weight balance of the motor unit is suppressed.

[0137] In the motor unit of Embodiment 1, the oil cooler 40 is located on the opposite side of the motor 10, separated from the reducer 20. Therefore, it is difficult to be affected by the heat generated by the motor 10, thereby suppressing the reduction of the cooling performance of the oil cooler 40.

[0138] In the motor unit of Embodiment 1, since the cooling oil inlet 30a of the oil pump 30 is located below the rotation axis of the gear rotation shaft 21 of the reducer 20, and the oil pump 30 is installed at the lower part of the other end face of the reducer 20, the cooling oil inlet 30a of the oil pump 30 is immersed in the storage part 82 of the gear housing 23. Therefore, it is possible to prevent insufficient suction of cooling oil by the oil pump 30 and to smoothly circulate the cooling oil.

[0139] In the motor unit of Embodiment 1, the gear housing 23 has a structure having a first gear housing 23a and a second gear housing 23b, and the oil pump 30 and the oil cooler 40 are mounted on the other end face of the second gear housing 23b. Therefore, the oil pump 30 and the oil cooler 40, which are used for oil cooling, can be treated as a component mounted on the second gear housing 23b, thus improving assemblability.

[0140] In the motor unit of Embodiment 1, the inverter unit 50 adopts a structure in which one side faces the non-contact surface of one end face of the motor 10 and the bottom surface is mounted on one side of the reducer 20. Therefore, the space formed by the motor 10 and the reducer 20 can be effectively utilized for the installation of the inverter unit 50 on the reducer 20, thereby realizing the miniaturization of the external size of the motor unit.

[0141] In the motor unit of Embodiment 1, a portion of the bottom surface of the inverter unit 50 is positioned opposite one side of the oil pump 30 and one side of the oil cooler 40, while the remaining bottom surface portion is mounted to one side of the reducer 20. Therefore, the space formed by the reducer 20 and the inverter unit 50 can be effectively utilized for mounting the oil pump 30 and the oil cooler 40 to the reducer 20, thereby achieving miniaturization of the overall size of the motor unit.

[0142] Implementation method 2. use Figure 5 The motor unit of Embodiment 2 will be described.

[0143] The motor unit of Embodiment 2 differs from the motor unit of Embodiment 1 in that an oil filter 60 is included in the front section of the cooling oil inlet 30a of the oil pump 30 inside the cooling oil storage section 82 of the gear housing 23 of the reducer 20. All other points are the same.

[0144] In addition, Figure 5 In, with Figures 1 to 4 The same symbols indicate the same or equivalent parts.

[0145] The motor unit in Embodiment 2 includes an electric motor 10, a reducer 20, an oil pump 30, an oil cooler 40, an inverter unit 50, and an oil filter 60.

[0146] The motor 10, reducer 20, oil pump 30, oil cooler 40, and inverter unit 50 in the motor unit of Embodiment 2 are the same as those in the motor unit of Embodiment 1, therefore, their descriptions are omitted.

[0147] like Figure 5 As shown, the oil filter 60 is configured to face the front section of the cooling oil inlet 30a of the oil pump 30.

[0148] The oil filter 60 is fixed inside the cooling oil storage section 82 in the gear housing 23 of the reducer 20.

[0149] Since the oil filter 60 is configured to face the front of the cooling oil inlet 30a of the oil pump 30, impurities in the cooling oil stored in the cooling oil storage section 82 of the gear housing 23 of the reducer 20 can be effectively removed by the oil filter 60 configured at the front of the cooling oil inlet 30a of the oil pump 30.

[0150] Furthermore, the side surface of one end face of the storage section 82 is formed by the second gear housing 23b, and the oil filter 60 is installed on the inner surface of the side surface of the storage section 82 formed by the second gear housing 23b. Thus, the oil pump 30, the oil cooler 40 and the oil filter 60 can be treated as a component installed in the second gear housing 23b, thereby improving assemblability.

[0151] In addition to having the same effects as the motor unit in Embodiment 1, the motor unit of Embodiment 2 can effectively remove impurities from the cooling oil by placing the oil filter 60 inside the cooling oil storage section 82 of the gear housing 23 of the reducer 20.

[0152] Furthermore, various embodiments can be freely combined, or any constituent elements of each embodiment can be modified, or any constituent elements can be omitted in each embodiment.

[0153] Industrial availability The motor unit disclosed herein is suitable for use in the power transmission system of an electric vehicle powered by a motor and includes an electric motor and a speed reducer. Such electric vehicles powered by motors include, for example, electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHVs).

[0154] Symbol Explanation 10 Electric motor; 11 Rotor; 12 Stator; 12a Front coil end; 12b Rear coil end; 13 Housing; 13a Main body; 13b Front cover; 14 Front bearing; 15 Rear bearing; 20 Reducer; 21 Gear rotating shaft; 22 Reduction mechanism; 23 Gear housing; 23a First gear housing; 23b Second gear housing; 30 Oil pump; 40 Oil cooler; 50 Inverter unit; 60 Oil filter; 61 Oil circuit (first oil circuit); 62 Second oil circuit; 63 Third oil circuit; 64 Fourth oil circuit; 71-74 Outflow path; 81, 82 Storage section.

Claims

1. A motor unit, characterized in that, include: An electric motor having a rotor, a stator, and a housing, the housing housing internally housing the rotor and the stator, having an oil passage for cooling oil to flow through and an outlet passage for cooling oil to flow from the oil passage to the stator in the upper part, and having a storage part for cooling oil in the lower part. The speed reducer has a speed reduction mechanism composed of multiple gears and a gear housing. The gear housing houses the speed reduction mechanism inside and has a storage part for cooling oil in the lower part that communicates with the storage part of the housing. The speed reducer has one end face of the motor mounted on the other end face and transmits the speed of rotation of the motor after reducing the speed. An oil pump is installed at one end face of the reducer to draw up the cooling oil accumulated in the storage part of the gear housing and circulate the cooling oil in the oil passage of the housing. as well as An oil cooler is installed on one end face of the reducer. The inlet of the oil cooler is connected to the outlet of the cooling oil of the oil pump. The oil cooler cools the cooling oil from the outlet of the oil pump and allows the cooled oil to flow out from the outlet into the cooling oil flow path between the outlet and the inlet of the oil passage of the housing.

2. The motor unit according to claim 1, characterized in that, The outer casing has an oil pan for storing cooling oil. The gear housing has an oil pan for storing cooling oil. The cooling oil inlet of the oil pump is located below the rotation axis of the gear shaft of the reducer, which is connected to the rotation axis of the rotor of the electric motor, and is immersed in the oil pan of the gear housing.

3. The motor unit according to claim 1, characterized in that, The oil passage of the outer casing is a first oil passage formed above the stator. A second oil passage is provided in the upper part of the gear housing. The outlet of the second oil passage is connected to the inlet of the first oil passage, which is located between one end face of the motor and the other end face of the reducer. The motor unit further includes: a third oil passage connecting the cooling oil outlet of the oil pump to the cooling oil inlet of the oil cooler; and a fourth oil passage connecting the cooling oil outlet of the oil cooler to the cooling oil inlet of the second oil passage. The housing has the following outflow paths: a front coil end outflow path for cooling oil to flow from the first oil passage to the front coil end of the stator; and a rear coil end outflow path for cooling oil to flow from the first oil passage to the rear coil end of the stator. The outlet of the housing further includes: a front bearing outlet for which cooling oil flows from the first oil passage to the front bearing relative to the rotating shaft of the rotor; and a rear bearing outlet for which cooling oil flows from the first oil passage to the rear bearing relative to the rotating shaft of the rotor.

4. The motor unit according to claim 3, characterized in that, The gear housing has: The first gear housing is a cylindrical body with a bottom and an open end. The bottom surface of the other end face of the reducer is in contact with one end face of the motor, and the second oil passage is formed in the upper part of the first gear housing. as well as The second gear housing covers one end opening of the first gear housing, and the outer surface of one end face of the reducer contacts the oil pump and the oil cooler, and forms the third flow path.

5. The motor unit according to claim 4, characterized in that, The fourth oil passage is configured such that the first gear housing and the second gear housing are in contact.

6. The motor unit according to claim 4, characterized in that, The fourth oil passage is configured on the other end face of the first gear housing in a manner that connects with the second oil passage.

7. The motor unit according to claim 1, characterized in that, Viewed from the oil pump side, the motor side is fitted into one end face of the motor and onto the other end face of the lower reducer. Viewed from the oil cooler side, the oil cooler is installed inside one end face of the motor and on the other end face of the reducer, which is located above the oil pump.

8. The motor unit according to any one of claims 1 to 7, characterized in that, One end face of the electric motor is divided in two by a vertical line. One side is a contact surface including a through hole in the housing through which one end of the rotating shaft is inserted, and the other side is a non-contact surface. The contact surface on one end face of the motor contacts the contact surface on the other end face of the reducer, thereby mounting the motor to the reducer. The motor unit includes an inverter unit for controlling the motor. One side of the inverter unit is opposite to a non-contact surface of one end face of the motor, and the bottom surface of the inverter unit is mounted to one side of the reducer.

9. The motor unit according to claim 8, characterized in that, In the oil cooler, the cooling oil that has passed through the oil cooler exchanges heat with the refrigerant that has cooled the inverter unit and is thus cooled.

10. The motor unit according to claim 7, characterized in that, One end face of the electric motor is divided in two by a vertical line. One side is a contact surface including a through hole in the housing through which one end of the rotating shaft is inserted, and the other side is a non-contact surface. The contact surface on one end face of the motor contacts the contact surface on the other end face of the reducer, thereby mounting the motor to the reducer. The motor unit includes an inverter unit for controlling the motor. One side of the inverter unit is opposite to a non-contact surface of one end face of the motor. A portion of the bottom surface of the inverter unit is opposite to one side of the oil pump and one side of the oil cooler. The remaining bottom surface is mounted to one side of the reducer.

11. The motor unit according to any one of claims 1 to 7 and 10, characterized in that, An oil filter is included inside the cooling oil storage section of the gear housing of the reducer, in front of the cooling oil inlet of the oil pump.

Images