Motor unit and electric vehicle

Abstract

A motor and a housing are included. The motor has a rotor and a stator. The housing is cylindrical, has a first housing, a second housing, and a partition wall. The first housing houses the motor. The second housing is disposed adjacent to the motor chamber and accumulates a cooling medium that cools the motor. The partition wall is formed to space the first housing and the second housing apart and to project from an inner peripheral surface toward a radially inner side. The partition wall is provided with a through-hole that communicates an inside of the first housing and an inside of the second housing. The housing has a bypass flow path. The bypass flow path is disposed outside the first housing and the second housing, and communicates a flow inlet that opens to the inside of the first housing and a flow outlet that opens to the inside of the second housing.

Description

Technical Field

[0001] This invention relates to a motor unit and an electric vehicle. Background Technology

[0002] The existing motor unit is installed in the vehicle body and includes a first housing (motor housing), a second housing (gear housing), and a partition wall separating the first and second housings. The first housing houses the motor, which has a rotor that rotates around a motor axis. A through hole (communication port) is formed in the partition wall. Cooling medium (oil) after cooling the motor flows from the first housing to the second housing through the through hole (for example, see Japanese Patent Application Laid-Open No. 2016-208722).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2016-208722. Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, in such motor units, sometimes, due to the left-right swaying and tilting of the vehicle body, the oil cannot flow smoothly to the partition wall side and thus remains in the first housing. At this time, the following problems exist: when the rotor rotates, the losses caused by the stirring of the retained cooling medium increase, the rotational resistance of the rotor increases, and the driving efficiency of the motor unit decreases.

[0008] The purpose of this invention is to provide a motor unit and an electric vehicle including the motor unit, which can reduce the reduction in drive efficiency.

[0009] Technical solutions adopted to solve technical problems

[0010] An exemplary motor unit of the present invention includes a motor and a housing. The motor has a rotor and a stator. The rotor rotates about a motor axis. The stator is radially opposite the rotor with a gap. The housing is cylindrical and has a first housing, a second housing, and a partition wall. The first housing houses the motor. The second housing is disposed adjacent to the motor chamber and stores a cooling medium for cooling the motor. The partition wall is formed to space the first housing and the second housing and protrudes radially inward from its inner circumference. The partition wall has a through hole that communicates the interior of the first housing with the interior of the second housing to guide the cooling medium from the first housing to the second housing. The housing has a bypass flow path for communication of the cooling medium. The bypass flow path is disposed outside the first housing and the second housing, such that an inlet opening toward the interior of the first housing communicates with an outlet opening toward the interior of the second housing.

[0011] Invention Effects

[0012] According to the exemplary invention, a motor unit and an electric vehicle including the motor unit can be provided, which can reduce the reduction in drive efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating a general structure of an electric vehicle including the motor unit of the first embodiment of the present invention.

[0014] Figure 2 This is a schematic structural diagram illustrating the internal structure of the motor unit according to the first embodiment of the present invention.

[0015] Figure 3 This is a perspective view of the housing of the motor unit according to the first embodiment of the present invention.

[0016] Figure 4 This is a perspective view of the housing of the motor unit according to the first embodiment of the present invention.

[0017] Figure 5 This is a side view of the housing of the motor unit according to the first embodiment of the present invention.

[0018] Figure 6 This is a schematic structural diagram illustrating the internal structure of the motor unit according to the second embodiment of the present invention.

[0019] Figure 7 This is a side view of the housing of the motor unit according to the third embodiment of the present invention.

[0020] Figure 8 This is a side view of the housing of the motor unit according to the fourth embodiment of the present invention.

[0021] Figure 9 This is a perspective view of the housing of the motor unit according to the fifth embodiment of the present invention.

[0022] Figure 10 This is a schematic structural diagram illustrating the internal structure of the motor unit according to the sixth embodiment of the present invention.

[0023] Figure 11 This is a schematic structural diagram illustrating the internal structure of the motor unit according to the seventh embodiment of the present invention.

[0024] Figure 12 This is a schematic structural diagram illustrating the internal structure of the motor unit according to the seventh embodiment of the present invention.

[0025] Figure 13 This is a perspective view showing a portion of the first housing of the motor unit according to the seventh embodiment of the present invention.

[0026] Figure 14This is a perspective view showing a portion of the first housing of the motor unit according to the seventh embodiment of the present invention.

[0027] Figure 15 This is a perspective view showing a portion of the first housing of the motor unit according to the seventh embodiment of the present invention. Detailed Implementation

[0028] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification, the vertical direction is defined based on the positional relationship of the motor unit 1 mounted on a vehicle located on a horizontal road surface. In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional rectangular coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction with the +Z side as the upper side and the -Z side as the lower side. The X-axis direction is the direction orthogonal to the Z-axis direction, and it is the forward / backward direction of the vehicle on which the motor unit 1 is mounted. In this embodiment, the +X side is the front side of the vehicle, and the -X side is the rear side of the vehicle. The Y-axis direction is the direction orthogonal to both the X-axis and Z-axis directions, and it is the left / right direction of the vehicle. In this embodiment, the +Y side is the left side of the vehicle, and the -Y side is the right side of the vehicle.

[0029] Furthermore, the front-to-back positional relationship is not limited to that of this embodiment; it can also be that the +X side is the rear of the vehicle and the -X side is the front of the vehicle. In this case, the +Y side is the right side of the vehicle and the -Y side is the left side of the vehicle.

[0030] The motor axis J1, as appropriately shown in the figures, extends along the Y-axis direction, i.e., the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the motor axis J1 will be simply referred to as "axial," the radial direction centered on the motor axis J1 will be simply referred to as "radial," and the circumferential direction centered on the motor axis J1, i.e., the direction around the motor axis J1, will be simply referred to as "circumferential." Furthermore, in this specification, "parallel direction" also includes substantially parallel directions, and "orthogonal direction" also includes substantially orthogonal directions.

[0031] <First Implementation>

[0032] <1. Overall Structure of Electric Vehicles>

[0033] The electric vehicle 100 of the first exemplary embodiment of the present invention will be described below. Figure 1 This is a schematic structural diagram of an electric vehicle 100 including a motor unit 1 according to an embodiment of the present invention. The electric vehicle 100 includes a motor unit 1, a chassis 130, a pair of left and right drive wheels 110, and a pair of left and right driven wheels 120. The drive wheels 110 are driven to rotate by the motor unit 1.

[0034] The chassis 130 forms the skeleton of the electric vehicle 100, and a space for the motor unit 1 is disposed at the front bottom of the electric vehicle 100. The motor unit 1 serves as the driving force source for the electric vehicle 100. The motor power from the motor unit 1 is transmitted to a pair of drive wheels 110 via the drive shaft DS. The drive shaft DS extends along the differential axis J3 of the motor unit 1, which will be described later.

[0035] <2. Overall Structure of the Motor Unit>

[0036] Figure 2 This is a schematic diagram showing the internal structure of motor unit 1. Motor unit 1 includes a cylindrical housing 10, a motor 20, a transmission device 50 including a reduction gear 30 and a differential gear 40, a pump 70, a cooler 75, and pipes 78.

[0037] <3. Structure of the outer shell>

[0038] The housing 10 houses the motor 20 and the transmission device 50. The housing 10 has a first housing 11, a second housing 12, a partition wall 13, and a bypass flow path 15. For example, the first housing 11, the second housing 12, the partition wall 13, and the bypass flow path 15 are formed by die casting.

[0039] The first housing 11 surrounds the motor 20 radially outward, thus housing the motor 20. The first housing 11 has a cylindrical peripheral wall portion 11a extending axially and a side wall portion 11b that closes the right side of the peripheral wall portion 11a. The peripheral wall portion 11a is radially opposed to the stator 22, which will be described later.

[0040] The second housing 12 radially surrounds the reduction gear 30 and the differential gear 40, housing them. That is, the transmission device 50 is housed within the second housing 12. The second housing 12 has an axially extending cylindrical peripheral wall portion 12a and a side wall portion 12b that closes the left side of the peripheral wall portion 12a. The second housing 12 is disposed adjacent to the first housing 11. At least a portion of the bottom inside the second housing 12 is located lower than the bottom inside the first housing 11.

[0041] A partition wall 13 separates the first housing 11 from the second housing 12, and is formed by protruding radially inward from the inner circumferential surface of the housing 10. The partition wall 13 holds the bearing 24, which will be described later. Furthermore, the partition wall 13 has a through hole 13a that allows communication between the interior of the first housing 11 and the interior of the second housing 12. The through hole 13a is located at the lower end of the partition wall 13.

[0042] A bypass flow path 15 is disposed outside the first housing 11 and the second housing 12, with an inlet 15a open at one end and an outlet 15b open at the other end. The inlet 15a is disposed on the peripheral wall portion 11a and opens toward the interior of the first housing 11. The outlet 15b opens toward the interior of the second housing 12.

[0043] The inlet 15a is located at the lower part of the first housing 11, and the outlet 15b is located at the lower part of the second housing 12.

[0044] The outer casing 10 houses the oil (cooling medium) O, which serves as a refrigerant. An oil storage section P for storing the oil O is provided in the lower region inside the second casing 12. That is, the second casing 12 stores the oil O (cooling medium) used to cool the motor. A through-hole 13a directs the oil O from the first casing 11 to the second casing 12. Furthermore, a bypass flow path 15 supplies the flow of oil O.

[0045] Oil O from the oil reservoir P is delivered to the interior of the first housing 11 via oil passage 90 (described later). The oil O delivered to the interior of the first housing 11 accumulates in the lower region of the interior of the first housing 11. At least a portion of the oil O accumulated inside the first housing 11 flows through the through hole 13a and the bypass flow path 15 to the second housing 12, thereby returning to the oil reservoir P. Because the bypass flow path 15 is provided in addition to the through hole 13a, the oil O in the first housing 11 can easily flow to the second housing 12.

[0046] With the motor shaft J1 arranged horizontally, the lower end of the outlet 15b is positioned below the lower end of the inlet 15a. This allows oil O to flow smoothly within the bypass flow path 15. Furthermore, the lower ends of the through hole 13a and the inlet 15a are positioned below the lower end of the rotor 21 (described later). This prevents the level of oil O accumulated inside the first housing 11 from rising above the lower end of the rotor 21. Therefore, the oil O retained within the first housing 11 can suppress the increase in rotational resistance of the rotor 21. This reduces the decrease in the drive efficiency of the motor unit 1.

[0047] Oil O is the cooling medium used to cool the motor 20, and it circulates within the oil circuit 90 described later. Oil O is used for lubrication of the reduction gear 30 and the differential gear 40. As for Oil O, in order to perform the functions of lubricating oil and cooling oil, it is preferable to use an oil with a low viscosity, equivalent to automatic transmission fluid (ATF).

[0048] <3. Motor Structure>

[0049] Motor 20 is an internal rotor type motor. Motor 20 includes a rotor 21, a stator 22, and bearings 23, 24, and 25. Rotor 21 rotates about a motor axis J1 extending in the horizontal direction. Rotor 21 has a shaft 211 and a rotor body 212. Rotor body 212 has a rotor core (not shown) and rotor magnets (not shown) fixed to the rotor core. The torque of rotor 21 is transmitted to transmission device 50.

[0050] Shaft 211 extends axially around motor axis J1. Shaft 211 rotates around motor axis J1. Shaft 211 is a hollow shaft with a hollow portion 211 inside. Shaft 211 is provided with a connecting hole 211b. The connecting hole 211b connects the hollow portion 211a to the outside of shaft 211.

[0051] Shaft 211 extends through the interior of the first housing 11 and the interior of the second housing 12. A first gear 31 of the reduction gear 30 (described later) is fixed to the left end of shaft 211. Shaft 211 is supported by bearings 23, 24, and 25 for rotation. Bearings 23, 24, and 25 are, for example, ball bearings. Bearing 23 is held in sidewall 11b. Bearing 24 is held in partition wall 13. Bearing 25 is held in sidewall 12b.

[0052] The stator 22 and rotor 21 are positioned radially outwards across a gap. The stator 22 has a stator core 221 and a plurality of coils 222. The stator core 221 surrounds the rotor 21. The stator core 221 has an axially extending cylindrical core back (not shown) and a plurality of pole teeth (not shown) extending radially inwards from the core back. The plurality of pole teeth are arranged at equal intervals along the circumference.

[0053] Multiple coils 222 are mounted on each pole tooth of the stator core 221 via insulating members (not shown). The multiple coils 222 are arranged circumferentially.

[0054] <4. Structure of the transmission device>

[0055] The torque output from the motor 20 is transmitted to the differential device 40 via the reduction gear 30.

[0056] The reduction gear 30 is connected to the motor 20. That is, the transmission mechanism 50 is connected to the rotor 20. The reduction gear 30 reduces the speed of the motor 20 and increases the torque output from the motor 20 according to the reduction ratio. The reduction gear 30 transmits the torque output from the motor 20 to the differential gear 40. The reduction gear 30 has a first gear 31, a second gear 32, a third gear 33, and an intermediate shaft 35.

[0057] The first gear 31 is fixed to the outer circumferential surface of the left end of the shaft 211. The first gear 31 rotates together with the motor shaft 211 around the motor axis J1. The intermediate shaft 35 extends along the intermediate axis J2, which is parallel to the motor axis J1. The intermediate shaft 35 rotates around the intermediate axis J2. The second gear 32 and the third gear 33 are fixed to the outer circumferential surface of the intermediate shaft 35. The second gear 32 and the third gear 33 are connected through the intermediate shaft 35 and rotate around the intermediate axis J2. The second gear 32 meshes with the first gear 31. The third gear 33 meshes with the gear ring 41 of the differential device 40 (described later).

[0058] The torque output from the motor 20 is transmitted sequentially to the gear ring 41 of the differential device 40 via shaft 211, first gear 31, second gear 32, intermediate shaft 35, and third gear 33. The gear ratio and number of gears can be varied according to the required reduction ratio. In this embodiment, the reduction device 30 is a parallel shaft gear reducer with the shafts of each gear arranged in parallel.

[0059] The differential 40 is connected to the motor 20 via the reduction gear 30. The differential 40 transmits the torque output from the motor 20 to the vehicle's wheels. When the electric vehicle 100 turns, the differential 40 absorbs the speed difference between the left and right drive wheels 110 and transmits the same torque to the drive shafts DS of both wheels. The differential 40 has a gear ring 41, a gear housing (not shown), a pair of pinions (not shown), a pinion shaft (not shown), and a pair of side gears (not shown). The gear ring 41 rotates about a differential axis J3 parallel to the motor axis J1. The torque output from the motor 20 is transmitted to the gear ring 41 via the reduction gear 30.

[0060] <5. Structure of the oil circuit>

[0061] The motor 20 is provided with an oil passage 90 that circulates oil O within the housing 10. The oil passage 90 is the path that supplies oil O from the oil reservoir P to the motor 20 and then guides it back to the oil reservoir P. The oil passage 90 spans the interior of the first housing 11 and the interior of the second housing 12.

[0062] Furthermore, in this specification, "oil path" refers to the path of oil O. Therefore, the concept of "oil path" includes not only the "flow path" that forms the flow of oil that always faces one direction, but also the path that temporarily retains oil O and the path that supplies oil O for dripping. Paths that temporarily retain oil include, for example, reservoirs for storing oil O.

[0063] The oil passage 90 has a first oil passage 91 and a second oil passage 92. The first oil passage 91 and the second oil passage 92 respectively supply oil for circulation inside the housing 10.

[0064] <5-1. Structure of the First Oil Circuit>

[0065] The first oil passage 91 has a lifting path 91a, a shaft supply path 91b, an internal shaft path 91c, and an internal rotor path 91d. Furthermore, a first reservoir 93 is provided within the path of the first oil passage 91. The first reservoir 93 is disposed within the second housing 12.

[0066] The lifting path 91a is a path in which the oil O is lifted from the oil storage section P by the rotation of the gear ring 41 of the differential device 40 and received by the first reservoir 93. The first reservoir 93 opens upward. The first reservoir 93 receives the oil O lifted by the gear ring 41.

[0067] The shaft supply path 91b is the path that guides oil O from the first reservoir 93 to the hollow portion 211a of the shaft 211.

[0068] The internal shaft path 91c is the path through which oil O passes through the hollow portion 211a of the shaft 211. In the internal shaft path 91c, as the rotor 21 rotates, centrifugal force is applied to the oil O inside the rotor 21. As a result, oil O continuously splashes radially outward from the rotor 21. Furthermore, with the splashing of oil O, the internal path of the rotor 21 becomes negatively pressured, and the oil O accumulated in the first reservoir 93 is drawn towards the interior of the rotor 21, thereby filling the internal path of the rotor 21 with oil O.

[0069] The rotor internal path 91d is a path from the connecting hole 211 of the shaft 211 through the interior of the rotor body 212 and splashes onto the stator 22. The rotor internal path 91d has a supply port 212a provided in the rotor body 212. The supply port 212a opens toward the interior of the first housing 11. Oil O passing through the rotor internal path 91d is sprayed from the supply port 212a toward the stator 22. For example, multiple supply ports 212a are provided.

[0070] The oil O reaching the stator 22 absorbs heat from the stator 22. After cooling the stator 22, the oil O drips downwards and accumulates in the lower region of the first housing 11. The oil O accumulated in the lower region of the first housing 11 flows to the second housing 12 via the through hole 13a and the bypass flow path 15. As described above, the first oil passage 91 supplies oil O to the rotor 21 and the stator 22.

[0071] <5-2. Structure of the Second Oil Circuit>

[0072] In the second oil passage 92, oil O is pumped from the oil reservoir P and supplied to the stator 22. The second oil passage 92 is equipped with a pump 70, a cooler 75, and a pipe 78. The second oil passage 92 has a first flow path 92a, a second flow path 92b, a third flow path 92c, and a fourth flow path 92d.

[0073] First flow path 92a, second flow path 92b, third flow path 92c, and fourth flow path 92d are disposed on the wall of housing 10. First flow path 92a connects oil reservoir P to pump 70. Second flow path 92b connects pump 70 to cooler 75. Third flow path 92c connects cooler 75 to fourth flow path 92d. Fourth flow path 92d connects third flow path 92c to pipe 78. Fourth flow path 92d is disposed on partition wall 13.

[0074] The conduit 78 extends in a straight line in the axial direction, for example, disposed on the upper side of the stator 22. The conduit 78 is housed inside the housing 10, and the left end of the conduit 78 is fixed to the partition wall 13. The conduit 78 is located radially outward of the stator 22.

[0075] The conduit 78 has supply ports 78a and 78b that open toward the interior of the first housing 11. Oil O flowing into the conduit 78 from the fourth flow path 92d is sprayed from the supply ports 78a and 78b toward the stator 22. The oil O sprayed from the supply port 78a is supplied to the stator core 221. The oil O sprayed from the supply port 78b is supplied to the coil 222.

[0076] Pump 70 is a pump that delivers oil O as a cooling medium. In this embodiment, pump 70 is an electrically driven pump. Pump 70 draws oil O from the oil storage section P through the first flow path 92a and supplies oil O to the motor 20 through the second flow path 92b, cooler 75, third flow path 92c, fourth flow path 92d, and pipe 78. That is, pump 70 circulates the oil (cooling medium) O stored in the second housing 12 within the first housing 11.

[0077] Oil O supplied from pipe 78 to stator 22 drips downwards and accumulates in the lower region of the first housing 11. The oil O accumulated in the lower region of the first housing 11 flows through through hole 13a and bypass flow path 15 to oil storage section P of second housing 12. As described above, second oil passage 92b supplies oil O to stator 22.

[0078] Cooler 75 cools the oil O passing through the second oil passage 92b. Cooler 75 has a flow path 75a that connects the second flow path 92b to the third flow path 92c. Flow path 75a is located inside cooler 75. A cooling water pipe 75b is connected to cooler 75, through which cooling water cooled by the radiator (not shown) passes. The oil O passing through flow path 75a inside cooler 75 is cooled by heat exchange with the cooling water passing through cooling water pipe 75b.

[0079] The motor unit 1 also includes a temperature sensor (not shown) capable of detecting the temperature of the motor 20. The type of temperature sensor is not limited as long as it can detect the temperature of the motor 20. The motor unit 1 controls the drive of the pump 70 based on the detection results of the temperature sensor. For example, if the motor unit 1 determines, based on the detection results of the temperature sensor, that the temperature of the stator 22 is above a predetermined threshold, it increases the output of the pump 70.

[0080] <6. Positional Relationship Between Through-hole and Bypass Flow Path>

[0081] Figure 3 , Figure 4 This is a 3D view of the outer casing 10. Figure 5 This is a side view of the outer casing 10. Additionally, Figure 3 , Figure 5 This is a view of the partition wall 13 from the side of the first outer shell 11. Figure 4 This is a view of the partition wall 13 from the side of the second outer shell 12.

[0082] The first housing 11 is cylindrical and has protrusions 111a, 111b, and 112 inside. The protrusions 111a, 111b, and 112 protrude radially inward from the inner surface of the first housing 11. The protrusions 111a and 111b extend axially and are arranged in multiples along the entire circumference, facing the stator 22 radially. The protrusion 112 is axially adjacent to the partition wall 13 and extends circumferentially. During the assembly of the motor unit 1, a portion of the stator 22 contacts the protrusions 111a, 111b, and 112. This facilitates the positioning of the motor 20 within the first housing 11.

[0083] The inlet 15a of the bypass flow path 15 is disposed between adjacent protrusions 111a. Furthermore, the inlet 15a opens radially inward and is disposed radially opposite to the stator 22. Thus, oil O dripping into the lower region inside the first housing 11 flows smoothly into the inlet 15a between adjacent protrusions 111a.

[0084] Furthermore, the axial end of one of the protrusions 111a adjacent to the inlet 15a, on the side opposite to the partition wall 13, is positioned closer to the partition wall 13 than the axial ends of the other protrusions 111b on the side opposite to the partition wall 13. Therefore, when the level of oil O remaining in the first housing 11 rises, oil O can easily flow into the inlet 15a from the axial end on the sidewall portion 11b of the protrusion 111a. Alternatively, the axial end of either of the protrusions 111a adjacent to the inlet 15a, on the side opposite to the partition wall 13, may be positioned closer to the partition wall 13 than the other protrusions 111b.

[0085] Furthermore, with the motor shaft J1 arranged horizontally, the height of the upper end of the inlet 15a is different from the height of the upper end of the through hole 13a. Therefore, even if the oil level in the first housing 11 is tilted, the oil in the first housing 11 can reliably flow out to the second housing 12 from either the inlet 15a or the through hole 13a. Furthermore, the upper end of the inlet 15a is positioned below the upper end of the through hole 13a. This prevents the oil level in the first housing 11 from rising above the upper end of the through hole 13a and above the lower end of the rotor 21. Alternatively, the upper end of the inlet 15a can be positioned above the upper end of the through hole 13a. In this case, a portion of the oil dripping onto the stator 22 flows out from the inlet 15a before flowing out from the through hole 13a. This prevents the oil level in the first housing 11 from rising above the lower end of the rotor 21.

[0086] Furthermore, the inlet 15a and the through hole 13a sandwich the surface H ( ) from the motor axis J1 downward in the vertical direction. Figure 5 (As shown by the dashed line) Openings are located on opposite sides in the circumferential direction. Thus, for example, when the electric vehicle 100 is tilted in the longitudinal direction on a slope or other location, the oil O inside the first housing 11 can reliably flow out to the second housing 12 from either the inlet 15a or the through hole 13a.

[0087] <Second Implementation>

[0088] Next, the second embodiment of the present invention will be described. Figure 6 This is a schematic diagram showing the internal structure of motor unit 1. For ease of explanation, the diagram is similar to the one described above. Figures 1-5 The same parts shown in the first embodiment are labeled with the same symbols. In the second embodiment, the shape of the bypass path 15 differs from that in the first embodiment. The other parts are the same as in the first embodiment.

[0089] The inlet 15a is disposed on the side wall portion 11b and opens toward the interior of the first housing 11. That is, the side of the first housing 11 opposite to the partition wall 13 in the axial direction is covered by the side wall portion 11b, and the inlet 15a is disposed on the side wall portion 11b. As a result, oil O that is retained in the gap between the side wall portion 11b and the stator 22 in the first housing 11 can flow out from the inlet 15a through the bypass flow path 15 to the second housing 12. Therefore, the same effect as in the first embodiment can be obtained.

[0090] <Third Implementation Method>

[0091] Next, the third embodiment of the present invention will be described. Figure 7 This is a side view of the outer casing 10. For ease of explanation, the view is similar to that described above. Figures 1-5 The same parts as in the first embodiment are labeled with the same symbols. In the third embodiment, the position of the inlet 15a differs from that in the first embodiment. The other parts are the same as in the first embodiment.

[0092] The inlet 15a and the through hole 13a open to the circumferential side relative to the surface H extending downward in the vertical direction from the motor axis J1. For example, if the oil O splashed from the supply port 212a is deflected to the forward side (+X side) due to the rotation of the rotor body 212, the oil O in the first housing 11 can flow smoothly out from the inlet 15a and the through hole 13a to the second housing 12.

[0093] <Fourth Implementation>

[0094] Next, the fourth embodiment of the present invention will be described. Figure 8 This is a side view of the outer casing 10. For ease of explanation, the view is similar to that described above. Figures 1-5 The same parts as in the first embodiment are labeled with the same symbols. In the fourth embodiment, the position of the inlet 15a differs from that in the first embodiment. The other parts are the same as in the first embodiment.

[0095] The inlet 15a is located on the lower side of the motor axis J1 in the vertical direction. As a result, the oil O that is retained at the bottom of the first housing 11 can flow out from the inlet 15a to the second housing 12.

[0096] <Fifth Implementation>

[0097] Next, the fifth embodiment of the present invention will be described. Figure 9 This is a perspective view of the outer casing 10. For ease of explanation, the aforementioned... Figures 1-5 The same parts shown in the first embodiment are labeled with the same symbols. In the third embodiment, the shape of the protrusion 111a differs from that in the first embodiment. The other parts are the same as in the first embodiment.

[0098] One of the protrusions 111a adjacent to the inlet 15a has a protruding groove 111c that is partially disposed in the axial direction and extends in the circumferential direction. Thus, oil O flowing along the peripheral wall 11a of the first housing 11 flows through the protruding groove 111c and easily flows into the inlet 15a. Alternatively, the protruding groove 111c may be provided on both of the protrusions 111a adjacent to the inlet 15a and on the protrusions 111b not adjacent to the inlet 15a.

[0099] <Sixth Implementation Method>

[0100] Next, the sixth embodiment of the present invention will be described. Figure 10This is a schematic diagram illustrating the internal structure of the motor unit 10. For ease of explanation, the diagram is similar to the one described above. Figures 1-5 The same parts as in the first embodiment are labeled with the same symbols. In the sixth embodiment, the position of the inlet 15a differs from that in the first embodiment. The other parts are the same as in the first embodiment.

[0101] The upper end of the inlet 15a is positioned above the lower end of the rotor 21. This allows oil O accumulated in the gap between the stator 22 and the rotor 21 to flow smoothly into the inlet 15a. Furthermore, the shape and position of the inlet 15a are not limited to the embodiment described above.

[0102] <Seventh Implementation>

[0103] Next, the seventh embodiment of the present invention will be described. Figure 11 , Figure 12 This is a schematic diagram showing the internal structure of motor unit 1. Figure 13 , Figure 14 , Figure 15 This is a perspective view showing a portion of the first housing 11 of the motor unit 1. For ease of explanation, the view is related to the aforementioned... Figures 1-5 The same parts shown in the first embodiment are labeled with the same symbols.

[0104] The partition wall 13 has a first opposing wall portion 131 and a second opposing wall portion 132. The first opposing wall portion 131 is disposed facing the interior of the first outer casing 11. The second opposing wall portion 132 is disposed facing the interior of the second outer casing 12. A space S is formed between the first opposing wall portion 131 and the second opposing wall portion 132 in the axial direction.

[0105] The first opposing wall portion 131 holds the bearing 24a. The second opposing wall portion 132 holds the bearing 24b. The shaft 211 is supported by bearings 23, 24a, 24b, and 25 to enable rotation.

[0106] The first opposing wall portion 131 has a through hole 131a extending axially. The second opposing wall portion 132 has a through hole 132a extending axially (see reference). Figure 12 The through hole 131a is a through hole that connects the space S to the interior of the first housing 11. The through hole 131a is located in a portion lower than the bearing 24a. The lower end of the through hole 131a is connected to the inner peripheral surface of the peripheral wall portion 11a.

[0107] The through hole 132a is a through hole that connects the space S to the interior of the second housing 12. The through hole 132a is located in a portion lower than the bearing 24b. For example, the through hole 132a is arranged opposite to the through hole 131a provided in the first opposing wall portion 131 with a gap between them.

[0108] In this embodiment, the partition wall 13 is formed by a first opposing wall portion 131 and a second opposing wall portion 132. That is, the partition wall 13 has through holes 131a and 131b, which communicate the interior of the first outer casing 11 with the interior of the second outer casing 12, thereby guiding the cooling medium from the first outer casing 11 to the second outer casing 12. Furthermore, in this embodiment, the partition wall 13 is formed by the first opposing wall portion 131 and the second opposing wall portion 132, which are axially opposed and separated by a space S. However, the space S may be omitted, and the partition wall 13 may be formed by a single, integral wall portion. In this case, the through holes axially penetrate the integral wall portion.

[0109] The housing 10 has a fluid flow path 350. The fluid flow path 350 is a flow path through which water W, as a cooling fluid, flows internally. At least a portion of the fluid flow path 350 is located radially outward from the motor 20. In this embodiment, almost the entire fluid flow path 350, except for its two axial ends, is located radially outward from the motor 20. The lower portion of the fluid flow path 350 is located between the main body 393c of the recovery flow path (described later) and the radial direction of the motor 20.

[0110] The fluid flow path 350 has multiple axial flow path sections 351, multiple first circumferential flow path sections 352a, and multiple second circumferential flow path sections 352b.

[0111] Multiple axial flow paths 351 extend axially. The multiple axial flow paths 351 are arranged at intervals in the circumferential direction. In this embodiment, the axial flow paths 351 are provided on the first housing 11. Figure 15 As shown, two of the multiple axial flow path sections 351 located on the lower side are arranged to sandwich the groove section 393a described later in the circumferential direction.

[0112] The first circumferential flow path 352a and the second circumferential flow path 352b extend in the circumferential direction. Multiple first circumferential flow path sections 352a are arranged at intervals in the circumferential direction. Multiple second circumferential flow path sections 352b are arranged at intervals in the circumferential direction. The first circumferential flow path sections 352a are connected to each other at their axial ends on the opposite side of the circumferential direction of adjacent axial flow path sections 351. By alternately connecting the axial ends of the axial flow path sections 351 to each other with the first circumferential flow path sections 352a and the second circumferential flow path sections 352b, the fluid flow path 350 is made to have a rectangular wave shape.

[0113] In the fluid flow path 350, water W flows along a rectangular wave-shaped flow path formed by the axial flow path 351, the first circumferential flow path 352a, and the second circumferential flow path 352b, and flows around the motor 20 once.

[0114] On the other hand, the oil O supplied to the stator 22 absorbs heat from the stator 22. After cooling the stator 22, the oil O falls downward and accumulates in the lower region inside the first housing 11. The oil O accumulated in the lower region inside the first housing 11 returns to the interior of the second housing 12 through the through holes 131a, 131b or the recovery flow path 393.

[0115] The recovery flow path 393 extends from the interior of the first housing 11 to the interior of the second housing 12. The recovery flow path 393 is located below the motor 20. The recovery flow path 393 has a groove 393a, a connecting portion 393b, and a recovery flow path body portion 393c. The groove 393a is provided on the inner peripheral surface of the first housing 11. In this embodiment, the groove 393a is recessed downward from the lower portion of the inner peripheral surface of the peripheral wall portion 11a of the first housing member 11. The groove 393a extends axially. The end of the groove 393a on one axial side is blocked. The end of the groove 393a on the other axial side opens at the end face of the peripheral wall portion 11a on the other axial side to form a flow inlet 15a. That is, the first housing 11 has a groove 393a provided on the inner peripheral surface and extending axially. The inlet 15a is disposed on the groove 393a, and the inlet 15a is disposed on the end opposite to the second housing 12 in the axial direction. The other end of the groove 393a in the axial direction is connected to the connecting part 393b.

[0116] The bottom surface of the groove 393a slopes downwards towards the opposite axial direction. That is, the bottom surface of the groove 393a is an inclined surface that slopes downwards towards the connecting portion 393b. Therefore, oil O entering the groove 393a can be easily guided to the connecting portion 393b along the bottom surface of the groove 393a using gravity. The bottom surface of the groove 393a is the radially outer surface of its inner surface and faces radially inwards. In this embodiment, the bottom surface of the groove 393a faces upwards. Figure 15 As shown, the circumferential dimension of the groove 393a is smaller than the circumferential dimension of the through holes 131a and 131b.

[0117] The connecting portion 393b connects the inlet 15a on the groove 393a to the main body of the recovery flow path 393c. The connecting portion 393b is also connected to the end 393f on the other axial side of the groove 393a. In this embodiment, the connecting portion 393b is provided on the peripheral wall 11a. The connecting portion 393b extends downward from the lower portion of the inner peripheral surface of the peripheral wall 11a. The connecting portion 393b opens upward. Figure 12 As shown, the lower end of the connecting portion 393b is connected to the axial end 393g of the main body portion 393c. Thus, the connecting portion 393b connects the axial end 393f of the groove portion 393a to the axial end 393g of the main body portion 393c.

[0118] The main body of the recovery flow path 393c is located radially outward from the groove portion 393a. In this embodiment, the main body of the recovery flow path 393c is located below the groove portion 393a. The main body of the recovery flow path 393c extends axially and connects to the interior of the second housing 12. The end portion 393p on one axial side of the main body of the recovery flow path 393c opens into the interior of the second housing 12 to form an outlet 15b. That is, the main body of the recovery flow path 393c is located radially outward from the groove portion 393a, extends axially, and the outlet 15b opens at its end. The main body of the recovery flow path 393c is located below the through holes 131a and 131b.

[0119] In this embodiment, the bypass flow path 15 is included in the recovery flow path 393. That is, the bypass flow path 15 is composed of a connecting portion 393b and a recovery flow path main body portion 393c, and is disposed outside the first housing 11 and the second housing 12. The bypass flow path 15 connects the inlet 15a, which opens on the groove portion 393a, with the outlet 15b, which opens at the end of the recovery flow path main body portion 393c. By providing the groove portion 393a, which is continuous with the bypass flow path 15, when the electric vehicle 100 is tilted in the left-right direction, the oil O in the first housing 11 can flow out more reliably from either the inlet 15a or the through hole 13a to the second housing 12.

[0120] like Figure 13 and Figure 14 As shown, the cross-section of the main body of the recovery flow path 393c is elongated in the circumferential direction. The circumferential dimension of the main body of the recovery flow path 393c is larger than the circumferential dimension of the groove 393a and the circumferential dimension of the connecting part 393b. Therefore, the flow rate of oil O flowing in the main body of the recovery flow path 393c can be increased. As a result, the amount of oil O returning from the first housing 11 to the second housing 12 can be increased.

[0121] At least a portion of the main body of the recovery flow path 393c is located radially outside the fluid flow path 350. Therefore, at least a portion of the recovery flow path 393 is located radially outside the fluid flow path 350. Figure 15As shown, a portion of the recovery flow path main body 393c is located below a pair of axial flow path portions 351, a first circumferential flow path portion 352c, and a pair of second circumferential flow path portions 352b in the fluid flow path 350. The pair of axial flow path portions 351 are configured to sandwich a groove portion 393a circumferentially, the first circumferential flow path portion 352c is located on one axial side of the groove portion 393a, and the pair of second circumferential flow path portions 352b are configured to sandwich a connecting portion 393b circumferentially. In this embodiment, as described above, the circumferential dimension of the recovery flow path main body 393c is larger than the circumferential dimensions of the groove portion 393a and the connecting portion 393b. Therefore, the recovery flow path main body 393c can protrude more circumferentially than the groove portion 393a and the connecting portion 393b. Therefore, the recovery flow path main body 393c can be easily positioned radially outside the fluid flow path 350.

[0122] A partition wall 393d is provided in the main body 393c of the recovery flow path, which circumferentially divides the interior of the main body 393c of the recovery flow path. The partition wall 393d roughly bisects the longer portion of the main body 393c of the recovery flow path along the circumference. The partition wall 393d improves the strength of the portion of the outer casing 10 in which the main body 393c of the recovery flow path is provided.

[0123] According to this embodiment, at least a portion of the fluid flow path 350 is located radially outside the motor 20. Therefore, the motor 20 can be cooled by the water W flowing within the fluid flow path 350. In this embodiment, the stator 22 can be cooled by the water W flowing within the fluid flow path 350. Furthermore, at least a portion of the recovery flow path 393 is located radially outside the fluid flow path 350. Therefore, the recovery flow path 393 can be positioned close to the fluid flow path 350. As a result, the oil O flowing through the recovery flow path 393 can be easily cooled by the water W flowing within the fluid flow path 350. Therefore, the temperature of the oil O flowing into the second housing 12 from the recovery flow path 393 can be reduced. Therefore, the temperature of the oil O supplied from the second housing 12 to the interior of the first housing 11 can be kept low. As a result, lower-temperature oil O can be supplied to the motor 20 housed in the first housing 11. Therefore, the motor 20 can be appropriately cooled by the lower-temperature oil O. Thus, in this embodiment, the motor 20 can be appropriately cooled by water W and oil O. Therefore, the cooling efficiency of the motor 20 can be improved. Furthermore, the motor 20 can be easily cooled even without a cooler such as an oil cooler for cooling the oil O. Therefore, the number of components in the motor unit 10 can be reduced accordingly compared to not having a cooler.

[0124] Furthermore, according to this embodiment, the recovery flow path 393 includes a groove portion 393a, a recovery flow path main body portion 393c, and a connecting portion 393b. The groove portion 393a is disposed on the inner circumferential surface of the first housing 11 and extends axially. The recovery flow path main body portion 393c is located radially outward from the groove portion 393a and extends axially to connect with the interior of the second housing 12. The connecting portion 393b connects the groove portion 393a and the recovery flow path main body portion 393c. Therefore, at least a portion of the oil O supplied to the first housing 11 can flow from the groove portion 393a into the recovery flow path 393. Furthermore, the oil O flowing into the groove portion 393a can be transported to the second housing 12 via the connecting portion 393b and the recovery flow path main body portion 393c. Thus, through the recovery flow path 393, oil O can be easily returned from the first housing 11 to the second housing 12. Furthermore, according to this embodiment, at least a portion of the recovery flow path main body 393c is located radially outside the fluid flow path 350. Therefore, the oil O flowing within the recovery flow path main body 393c can be easily cooled by the water W flowing within the fluid flow path 50.

[0125] Furthermore, according to this embodiment, the connecting portion 393b connects the end of the groove portion 393a on the other side of the axial direction to the end of the recovery flow path main body portion 393c on the other side of the axial direction. That is, the position where the groove portion 393a is connected to the recovery flow path main body portion 393c via the connecting portion 393b can be set to a position axially farther away from the second housing 12. Therefore, the flow distance of oil O from the connecting portion 393b into the recovery flow path main body portion 393c and then into the second housing 12 can be extended. Consequently, the time for cooling the oil O flowing in the recovery flow path main body portion 393c by the water W flowing in the fluid flow path 350 can be extended. Therefore, the water W flowing in the fluid flow path 350 can effectively cool the oil O flowing in the recovery flow path main body portion 393c. Therefore, it is easier to supply the motor 20 with lower temperature oil O. Therefore, the cooling efficiency of the motor 20 can be further improved.

[0126] <7. Other>

[0127] The embodiments of the present invention have been described above. However, the scope of the present invention is not limited to the above embodiments. Various modifications can be made to the present invention without departing from its spirit. Furthermore, the above embodiments can be appropriately combined in any way.

[0128] In this embodiment, only one bypass flow path 15 is provided; however, multiple bypass flow paths may also be provided. This allows oil O inside the first housing 11 to flow out to the second housing 12. Consequently, the bypass flow path 15 enables more reliable flow of oil O from the first housing 11 to the second housing 12.

[0129] Industrial availability

[0130] This invention can be used, for example, in electric vehicles (EVs) that have a motor unit and use a motor as a power source (including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHVs), etc.).

[0131] Symbol Explanation

[0132] 1 Motor Unit

[0133] 10. Outer shell

[0134] 11 First Outer Shell

[0135] 11a, 12a Peripheral wall

[0136] 11b, 12b sidewall portion

[0137] 12 Second outer shell

[0138] 13. Partition wall

[0139] 13a Through hole

[0140] 15 Bypass Flow Path

[0141] 15a Inlet

[0142] 15b Outlet

[0143] 20 motors

[0144] 21 Rotors

[0145] 22 Stator

[0146] Bearings 23, 24, and 25

[0147] 24a and 24b bearings

[0148] 30. Speed ​​reduction device

[0149] 31 First Gear

[0150] 32 Second Gear

[0151] 33 Third Gear

[0152] 35 Intermediate Shaft

[0153] 40 Differential device

[0154] 41 Gear Ring

[0155] 50 Transmission device

[0156] 70 pumps

[0157] 75 Cooler

[0158] 75a flow path

[0159] 75b Cooling water piping

[0160] 78 pipes

[0161] 78a, 78b supply ports

[0162] 90 oil circuit

[0163] 91 First Oil Route

[0164] 91a Lifting Path

[0165] 91b axis supply path

[0166] 91c In-axis path

[0167] 91d Rotor Internal Path

[0168] 92 Second oil line

[0169] 92a First flow path

[0170] 92b Second Flow Path

[0171] 92c Third Flowpath

[0172] 92d Fourth Flow Path

[0173] 93 First storage unit

[0174] 100 electric vehicles

[0175] 110 drive wheels

[0176] 111a, 111b, 112 Protrusions

[0177] 111c Protruding groove

[0178] 120 driven wheel

[0179] 130 chassis

[0180] 211 axis

[0181] 211a Hollow section

[0182] 211b Connecting hole

[0183] 212 Rotor body

[0184] 212a Supply Port

[0185] 221 Stator Core

[0186] 222 coil

[0187] 350 fluid flow path

[0188] 351 Axial flow path section 352a, 352c First circumferential flow path section

[0189] 352b Second week flow path section

[0190] 393 Recycle Flow Path

[0191] 393a Groove

[0192] 393b Connecting part

[0193] 393c Recycle Flow Path Main Body

[0194] 393d partition wall section

[0195] 393f end

[0196] 393g end

[0197] 393p end

[0198] DS drive shaft

[0199] H side

[0200] J1 motor shaft

[0201] J2 center axis

[0202] J3 Differential Axis

[0203] O oil

[0204] P Oil Storage Department

[0205] S Space

[0206] W Water.

Claims

1. A motor unit characterized by comprising: Comprising: a motor having a rotor rotating with a motor axis as a center and a stator opposed to the rotor with a gap on a radially outer side; and a cylindrical housing having a first housing accommodating the motor, a second housing disposed adjacent to the first housing and accumulating a cooling medium cooling the motor, and a partition wall formed to separate the first housing and the second housing and protruding from an inner peripheral surface to a radially inner side, the partition wall having a through hole communicating an inside of the first housing and an inside of the second housing to lead the cooling medium from the first housing to the second housing, the housing having a bypass flow path disposed outside the first housing and the second housing and communicating a flow inlet opening to an inside of the first housing and a flow outlet opening to an inside of the second housing to pass the cooling medium therethrough, the flow inlet and the through hole opening to circumferentially opposite sides with a face extending from the motor axis to a vertically lower side interposed therebetween in a state where the motor axis is disposed in a horizontal direction, the first housing having a peripheral wall portion opposed to the stator in a radial direction, a face of the first housing on an axially opposite side to the partition wall being covered by a side wall portion, a plurality of protrusion portions protruding from an inner surface of the first housing to the radially inner side and extending in the axial direction and opposed to the stator in the radial direction being provided circumferentially, the flow inlet being disposed between adjacent ones of the protrusion portions, the protrusion portions being provided on the peripheral wall portion and contacting at least a portion of the stator.

2. The motor unit according to claim 1, wherein a height of an upper end of the flow inlet is different from a height of an upper end of the through hole in a state where the motor axis is disposed in the horizontal direction.

3. The motor unit according to claim 1, wherein a lower end of the flow outlet is disposed at a position lower than a lower end of the flow inlet in a state where the motor axis is disposed in the horizontal direction.

4. The motor unit according to claim 1, wherein a lower end of the flow inlet is disposed at a position lower than a lower end of the rotor in a state where the motor axis is disposed in the horizontal direction.

5. The motor unit according to claim 4, wherein an upper end of the flow inlet is disposed at a position higher than the lower end of the rotor.

6. The motor unit according to claim 1, wherein the first housing has a groove portion provided to an inner peripheral surface of the first housing and extending in the axial direction, the flow inlet is disposed on the groove portion, the bypass flow path has: a recovery flow path main portion located at a position radially outer than the groove portion and extending in the axial direction, the flow outlet opening at an end portion of the recovery flow path main portion; and a connection portion connecting the flow inlet and the recovery flow path main portion.

7. The motor unit according to claim 6, wherein ​ The flow inlet is disposed at an end portion on an opposite side to the second housing in the axial direction.

8. The motor unit according to claim 6, wherein The bottom surface of the groove portion is an inclined surface inclined toward a lower side of the vertical direction as it goes toward the flow outlet.

9. The motor unit according to claim 6, wherein The circumferential dimension of the recovery flow path main portion is larger than the circumferential dimension of the connection portion.

10. The motor unit according to claim 6, wherein The housing has a fluid flow path disposed outside the first housing for the cooling fluid to flow inside, At least a portion of the recovery flow path main portion is located radially outside the fluid flow path.

11. The motor unit according to claim 1, wherein An axial end of the protrusion portion on an opposite side to the partition wall, which is adjacent to the flow inlet, is disposed at a position closer to the partition wall than an axial end of the other protrusion portion on an opposite side to the partition wall.

12. The motor unit according to claim 1, wherein The protrusion portion adjacent to the flow inlet has a protrusion groove portion disposed at a portion of the protrusion portion in the axial direction and extending in the circumferential direction.

13. The motor unit according to any one of claims 1 to 12, wherein The bypass flow path is provided in plural.

14. The motor unit of any one of claims 1 to 12, wherein, Further comprising: A transmission connected to the motor and housed in the second housing; and A pump that circulates the cooling medium stored in the second housing in the first housing.

15. An electric automobile, wherein The electric automobile includes the motor unit according to any one of claims 1 to 14.

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