JP4480433B2 - Motor cooling structure - Google Patents

Description

  The present invention relates to a cooling structure for an electric motor, and more particularly to a cooling structure using a cable connected to the electric motor.

  Conventionally, an in-wheel motor includes a motor, an oil pump, a case, and a wheel disk. The case is composed of a motor chamber and a pump chamber. The motor is housed in the motor chamber of the case, and the oil pump is housed in the pump chamber of the case.

  A case housing the motor and the oil pump is disposed to face the wheel disc. The oil pump then circulates the oil stored in the oil reservoir and cools the stator coil of the motor.

  As such an in-wheel motor, for example, Japanese Patent Laid-Open No. 2001-32914 (Patent Document 1) automatically adjusts the oil level to ensure a sufficient oil scooping amount during low-speed rotation, Disclosed is a drive unit lubrication device that prevents an increase in oil agitation loss during medium rotation. This drive unit lubrication device is a drive unit lubrication device in which a rotating member is housed in a case, and oil in an oil reservoir provided below the case is scraped and lubricated by the rotating member. In the lubricating device, a flange portion is formed on one side surface of the case so as to project inward at least a lower portion on a predetermined radius centered on the central axis of the rotating member. The lubrication device has a lid plate fixed to the end of the collar, and forms an oil reservoir chamber having an opening at the top and a discharge path at the bottom below the case-side empty space surrounded by the collar and the lid. To do. The lubricating device temporarily accumulates the scooped-up oil in the oil reservoir chamber, and changes the oil level of the oil reservoir.

According to the lubricating device disclosed in Patent Document 1, the oil level of the oil reservoir is high in the low rotation state immediately after the rotation of the rotating member starts. Further, even at a low rotation, a sufficient amount of oil can be scraped up to ensure lubrication or cooling. When the rotating member is moved from medium speed to high speed, the oil level in the oil reservoir is adjusted to be automatically lowered. This reduces loss due to oil agitation. Furthermore, it is possible to ensure a required amount of oil scooping at a high rotational speed.
JP 2001-32914 A

  However, the in-wheel motor tends to generate a large amount of heat due to iron loss, particularly when driven at a high speed, that is, when the vehicle is running at a high speed. The in-wheel motor that has generated heat due to iron loss transfers heat from the stator or coil end to the cooling medium by a cooling medium such as oil circulating in the case, and the stator or coil end is cooled. Then, heat is transferred from the cooling medium to the case, and is radiated to the outside of the case. At this time, it can be said that the cooling efficiency of the in-wheel motor depends on the heat capacity of the case. That is, it is necessary to further increase the heat capacity of the case in order to improve the efficiency of heat conduction from the cooling medium to the case, assuming that further heat generation occurs due to high-speed traveling or the like. If the volume of the case itself is increased in order to increase the heat capacity of the case, there is a problem that a sufficient mounting space for the in-wheel motor cannot be secured in the wheel.

  In Patent Document 1, since the heat of the cooling medium depends on the heat radiation to the case, the above-described problem may occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor cooling structure that improves cooling efficiency while securing a mounting space.

  An electric motor cooling structure according to a first aspect of the present invention is an electric motor cooling structure in which a cooling medium passage for circulating a cooling medium is provided in a housing that houses the electric motor. The cooling structure is formed of a member having a thermal conductivity higher than that of the housing, and includes a power transmission unit for supplying power to the electric motor and a heat transfer unit for transmitting heat from the cooling medium to the power transmission unit. .

  According to the first invention, the cooling structure is formed of a member having a higher thermal conductivity than at least the casing, and includes a power transmission means (for example, a power cable) for supplying power to the electric motor, and a power cable from the cooling medium. Heat transfer means (eg, a heat sink) for transferring heat to the heat sink. For example, the heat sink is provided inside the casing so as to contact the end of the power cable in the terminal block connecting the power cable and the electric motor. And the cooling medium channel | path provided in a housing | casing has a discharge outlet which discharges a cooling medium toward a heat sink. The cooling medium to which heat is transmitted from the stator and the coil end circulates in the cooling medium passage. Then, when the cooling medium is discharged toward the heat sink, heat is further transferred from the cooling medium to the heat sink. And since a heat sink is provided so that it may contact with the edge part of a power cable, heat | fever is transmitted from a heat sink to a power cable. Since the power cable has high thermal conductivity and has a sufficient length, heat dissipation to the atmosphere is also high. Therefore, the heat of the cooling medium can be radiated not only from the housing but also from the power cable. That is, heat generated in the stator, the coil end, and the like can be efficiently radiated without increasing the volume of the housing. Therefore, it is possible to provide a motor cooling structure that improves the cooling efficiency while securing the mounting space.

  In addition to the configuration of the first invention, the motor cooling structure according to the second invention further includes a connection member that is provided in the housing and connects the power transmission means and the motor. The heat transfer means is a heat radiating member provided in the housing so as to be in contact with the power transfer means in the connection member. The cooling medium passage has a discharge port that discharges the cooling medium toward the heat dissipation member.

  According to the second invention, the cooling structure further includes a connection member (for example, a terminal block) that is provided in the housing and connects the power transmission means (for example, the power cable) and the electric motor. The heat transfer means is a heat radiating member provided in the housing so as to be in contact with the power cable in the terminal block. The cooling medium passage has a discharge port that discharges the cooling medium toward the heat dissipation member. The cooling medium to which heat is transmitted from the stator and the coil end circulates in the cooling medium passage. Then, when the cooling medium is discharged toward the heat radiating member, heat is further transferred from the cooling medium to the heat radiating member. And since a heat radiating member is provided so that the edge part of a power cable may be contacted, heat | fever is transmitted from a heat radiating member to a power cable. Since the power cable has high thermal conductivity and has a sufficient length, heat dissipation to the atmosphere is also high. Therefore, the heat of the cooling medium can be radiated not only from the housing but also from the power cable.

  In the motor cooling structure according to the third aspect of the invention, in addition to the configuration of the second aspect of the invention, the heat dissipation member is a member having a fin shape.

  According to the third invention, the heat dissipation member is a member having a fin shape. When a heat sink having a fin shape is used as the heat radiating member, the surface area of the heat radiating member can be increased, so that heat conduction with the cooling medium can be performed efficiently.

  In addition to the configuration of the first invention, the motor cooling structure according to the fourth invention further includes a connection member provided in the housing and connecting the power transmission means and the motor. The heat transfer means is a fixing member that is provided in the housing and fixes the power transfer means and the connection member. The cooling medium passage has a discharge port that discharges the cooling medium toward the heat dissipation member.

  According to the fourth invention, the cooling structure further includes a connection member (for example, a terminal block) that is provided in the housing and connects the power transmission means (for example, the power cable) and the electric motor. The heat transfer means is a fixing member that is provided in the housing and fixes the power cable and the terminal block (for example, a nut that fastens the power cable and the terminal block). The cooling medium passage has a discharge port for discharging the cooling medium toward the nut. The cooling medium to which heat is transmitted from the stator and the coil end circulates in the cooling medium passage. And since a cooling medium is discharged toward a nut, heat is further transmitted from a cooling medium to a nut. And since the nut is fixing the edge part of a power cable, heat is transmitted from a nut to a power cable. Since the power cable has high thermal conductivity and has a sufficient length, heat dissipation to the atmosphere is also high. Therefore, the heat of the cooling medium can be radiated not only from the housing but also from the power cable.

  An electric motor cooling structure according to a fifth aspect of the present invention is an electric motor cooling structure provided in a casing that houses the electric motor. The cooling structure is formed of a member having a thermal conductivity higher than that of the casing, and includes a power transmission means for supplying power to the electric motor and a heat transfer means for transferring heat from the casing to the power transmission means. .

  According to the fifth invention, the cooling structure is formed of at least a member having a higher thermal conductivity than the casing, and a power transmission means (for example, a power cable) for supplying electric power to the motor, and the power cable from the casing. Heat transfer means (eg, a heat sink) for transferring heat to the heat sink. For example, the heat sink is provided in the housing so as to be in contact with the end portion of the power cable in the terminal block connecting the power cable and the electric motor. The heat transferred from the stator, the coil end, and the like to the housing is further transferred to the heat sink. And since a heat sink is provided so that it may contact with the edge part of a power cable, heat | fever is transmitted from a heat sink to a power cable. Since the power cable has high thermal conductivity and has a sufficient length, heat dissipation to the atmosphere is also high. Therefore, heat from the stator and the coil end can be radiated not only from the housing but also from the power cable. That is, heat generated in the stator, the coil end, and the like can be efficiently radiated without increasing the volume of the housing. Therefore, it is possible to provide a motor cooling structure that improves the cooling efficiency while securing the mounting space.

  In the motor cooling structure according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the heat transfer means is formed of a member having a higher thermal conductivity than at least the casing.

  According to the sixth invention, the heat transfer means is formed of a member having a higher thermal conductivity than at least the casing. Thereby, heat conduction to the cooling medium and the power cable can be performed efficiently.

  In the motor cooling structure according to the seventh aspect of the invention, in addition to the configuration of any one of the first to sixth aspects, the electric motor is a drive motor provided in the wheel of the vehicle.

  According to the seventh invention, the electric motor is a drive motor provided in the wheel of the vehicle. When applied to a vehicle having a so-called in-wheel motor in which an electric motor is provided in the wheel, heat generated by iron loss is dissipated not only from the housing but also from the power cable even when the vehicle is traveling at high speed. be able to.

  Hereinafter, a cooling structure for an electric motor according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. In addition, although the electric motor for a drive provided in the wheel of a vehicle, what is called an in-wheel motor is demonstrated as an electric motor which concerns on embodiment of this invention, it is not limited to this.

<First Embodiment>
FIG. 1 is a schematic cross-sectional view of an electric wheel provided with an in-wheel motor according to the first embodiment. Referring to FIG. 1, an electric wheel 100 includes a wheel disc 10, a hub 20, cases 30 and 31, a brake rotor 40, a brake caliper 50, a motor 60, bearings 73 to 76, and a planetary gear 80. An oil pump 90, a shaft 110, an oil passage 130, and a tire 140.

  The electric wheel 100 is suspended from the frame of the automobile body by an upper arm and a lower arm (not shown).

  The wheel disc 10 has a substantially cup shape and includes a low portion 10A and a cylindrical portion 10B. The wheel disc 10 houses the hub 20, cases 30 and 31, brake rotor 40, brake caliper 50, motor 60, bearings 71 to 76, planetary gear 80, oil pump 90, shaft 110, and oil passage 130. The wheel disc 10 is connected to the hub 20 by fastening the lower portion 10 </ b> A to the hub 20 with screws 1 and 2. The hub 20 is spline fitted to the shaft 110. The hub 20 spline-fitted to the shaft 110 is smoothly rotated by the bearings 71 and 72.

  The brake rotor 40 is arranged such that the inner peripheral end is fixed to the hub 20 by screws 3 and 4 and the outer peripheral end passes through the brake caliper 50. The brake caliper 50 includes a brake piston 51 and brake pads 52 and 53. The brake pads 52 and 53 sandwich the outer peripheral end of the brake rotor 40.

  When brake oil is supplied from the opening 50A, the brake piston 51 moves to the right side of the page and pushes the brake pad 52 to the right side of the page. When the brake pad 52 is moved to the right side of the drawing by the brake piston 51, the brake pad 53 is moved to the left side of the drawing in response. As a result, the brake pads 52 and 53 sandwich the outer peripheral end of the brake rotor 40 and the electric wheel 100 is braked.

  Cases 30 and 31 are arranged on the left side of the hub 20 in the drawing. The case 30 is connected to the case 31 by the screw 5. Cases 30 and 31 house the motor 60.

  The motor 60 includes a stator core 61, a stator coil 62, a rotor 63, and a rotor shaft 64. The stator core 61 is fixed to the case 31. The stator coil 62 is wound around the stator core 61. When motor 60 is a three-phase motor, stator coil 62 includes a U-phase coil, a V-phase coil, and a W-phase coil.

  The stator coil 62 has coil ends 62A and 62B. The coil end 62A is disposed on the oil pump 90 side, and the coil end 62B is disposed on the opposite side to the oil pump 90.

  The rotor shaft 64 supports the rotor 63. The rotor 63 and the rotor shaft 64 are disposed on the inner peripheral side of the stator core 61 and the stator coil 62.

  Planetary gear 80 includes a sun gear shaft 81, a sun gear 82, a pinion gear 83, a planetary carrier 84, and a ring gear 85. Sun gear shaft 81 is connected to rotor shaft 64 of motor 60. The sun gear shaft 81 is rotatably supported by bearings 73 and 74. The sun gear 82 is connected to the sun gear shaft 81.

  The pinion gear 83 meshes with the sun gear 82 and is rotatably supported by bearings 75 and 76. The planetary carrier 84 is connected to the pinion gear 83 and is splined to the shaft 110. The ring gear 85 is fixed to the case.

  The oil pump 90 is provided at one end of the shaft 110 (rotating shaft). Since the shaft 110 is spline-fitted with the hub 20 and the planetary carrier 84 as described above, the shaft 110 is rotatably supported by the bearing 76 and smoothly rotates by the bearings 71 and 72. The shaft 110 incorporates an oil passage 111 and an oil hole 112.

  The oil passage 121 is provided inside the pinion gear 83 of the planetary gear 80. The oil passage 130 has one end connected to the oil pump 90 and the other end inserted into the oil reservoir 120.

  The oil pump 90 pumps up the oil stored in the oil reservoir 120 through the oil passage 130 and supplies the pumped oil to the oil passage 111 and the oil pipe 200.

  The tire 140 is fixed to the outer edge of the cylindrical portion 10B of the wheel disc 10.

  When an alternating current is supplied to the stator coil 62 by a switching circuit (not shown) provided in the main body of the automobile on which the electric wheel 100 is mounted, the rotor 63 rotates and the motor 60 generates a predetermined torque. Output. The output torque of the motor 60 is transmitted to the planetary gear 80 via the sun gear shaft 81. The planetary gear 80 changes the output torque received from the sun gear shaft 81 by the sun gear 82 and the pinion gear 83, that is, changes speed and outputs it to the planetary carrier 84. The planetary carrier 84 transmits the output torque of the planetary gear 80 to the shaft 110, and the shaft 110 rotates the hub 20 and the wheel disc 10 at a predetermined number of rotations. Thereby, the electric wheel 100 rotates at a predetermined number of rotations.

  On the other hand, the oil pump 90 pumps oil from the oil reservoir 120 through the oil passage 130 and supplies the pumped oil to the oil passage 111 and the oil pipe 200 provided in the shaft 110.

  Then, the oil supplied to the oil passage 111 is discharged from the oil hole 112 by the centrifugal force generated by the rotation of the shaft 110 while moving in the oil passage 111. The oil passage 121 supplies the oil discharged from the shaft 110 to the planetary gear 80 and lubricates the planetary gear 80. Further, the oil discharged from the shaft 110 cools the coil end 62 </ b> A of the stator coil 62 and lubricates the bearings 73 to 76.

  The oil supplied to the oil pipe 200 is supplied to a terminal block (not shown) provided in the case 31.

  As shown in FIG. 2, a terminal block 308 is provided in the case 31 of the in-wheel motor. The terminal block 308 has terminal mounting portions 316, 318, and 320 that are connected to the U-phase coil, the V-phase coil, and the W-phase coil that are wound around the stator core 61, respectively. The case 31 is provided with a hollow protrusion 300 on the outside of the case 31 so as to surround the terminal block 308. Further, the end portions of the power cables 302, 304, and 306 are inserted through the projecting portion 300 from the upper arm side toward the lower side in the vertical direction.

  The power cables 302, 304, and 306 are conductive wires having higher thermal conductivity than the cases 30 and 31. In the present embodiment, for example, the material of the power cables 302, 304, and 306 is copper. The ends of the power cables 302, 304, and 306 have plate-like terminals 310, 312, and 314 having openings. Terminals 310, 312, and 314 are fastened to corresponding terminal mounting portions 316, 318, and 320 by bolts (not shown) and nuts (not shown), respectively. The terminals 310, 312, and 314 are not limited to fixing with bolts and nuts.

  The power cables 302, 304, and 306 receive supply of alternating current from a switching circuit mounted on the vehicle, and transmit power to the terminal mounting portions 316, 318, and 320. Then, AC current is transmitted from terminal mounting portions 316, 318, and 320 to each of the U-phase coil, V-phase coil, and W-phase coil, and a magnetic field is generated in stator coil 62A.

  The present invention is characterized in that heat is transferred from oil as a cooling medium to power cables 302, 304, and 306 connected to the in-wheel motor. In this embodiment, oil is used as the cooling medium, but is not particularly limited.

  As shown in FIG. 3, the power cable 304 is provided so as to penetrate the protruding portion 300. On the end side of the power cable 304, there is a flange-shaped protrusion 326 having an opening. After the end portion of the power cable 304 is penetrated, the bolt 328 is passed through the opening of the flange-shaped protrusion 326 and fastened to the protrusion 300. Further, the terminal 312 of the power cable 304 is fastened to the terminal mounting portion 318 by a bolt 322 and a nut 324. Terminal attaching portion 318 is connected to any of the U-phase coil, V-phase coil, and W-phase coil via connection member 332. The opening of the protrusion 300 opened to the outside of the case 31 is shielded by a cover (not shown) to prevent leakage of oil in the case 31 to the outside.

  A heat sink 330 is provided in contact with the end of the power cable 304. The heat sink 330 is preferably provided at each end of the power cables 302, 304, and 306. Further, the heat sink 330 is formed of a member having a higher thermal conductivity than at least the case 31. In the present embodiment, the material of the heat sink 330 is, for example, copper. The heat sink 330 preferably has a fin shape.

  Further, one end of the oil pipe 200 whose other end is connected to the oil pump 90 passes through the protruding portion 300. The discharge port at one end of the oil pipe 200 is provided toward the heat sink 330. The shape of the discharge port is not particularly limited. For example, the power cables 302, 304, and 306 may have a plurality of discharge ports that branch toward the respective heat sinks 330, or oil diffuses from one discharge port toward the respective heat sinks 330. You may have the discharge outlet which discharges.

  The operation of the cooling structure for the in-wheel motor according to the present embodiment based on the above structure will be described.

  Oil pumped from the oil pump 90 is discharged from the discharge port through the oil pipe 200. At this time, since the discharge port is provided toward the heat sink 330, the oil discharged from the discharge port contacts the heat sink 330. At this time, heat is transferred from the oil to the heat sink 330. The heat transmitted to the heat sink 330 is transmitted to each of the power cables 302, 304, and 306 provided so as to be in contact with the heat sink 330. The heat transmitted to the power cables 302, 304, and 306 is radiated from the power cables 302, 304, and 306 to the atmosphere. The oil after contacting the heat sink 330 flows into the oil reservoir 120 and is pumped up again by the oil pump 90.

  As described above, according to the cooling structure of the electric motor according to the present embodiment, the cooling structure is formed of a member having at least a thermal conductivity higher than that of the case, and a power cable for supplying electric power to the electric motor, and an oil Heat sink to transfer heat to the power cable. The heat sink is provided inside the case so as to come into contact with the end portion of the power cable in the terminal block connecting the power cable and the electric motor. The oil pipe provided in the case has a discharge port that discharges oil toward the heat sink. The oil that has been transferred with heat from the stator and coil ends circulates in the oil pipe. Then, the oil is discharged toward the heat sink, whereby heat is further transferred from the oil to the heat sink. And since a heat sink is provided so that it may contact with the edge part of a power cable, heat is transmitted from a heat sink to a power cable. Since the power cable has high thermal conductivity and has a sufficient length, heat dissipation to the atmosphere is also high. Therefore, the heat of oil can be radiated not only from the case but also from the power cable. That is, it is possible to efficiently dissipate heat generated in the stator and the coil end without increasing the volume of the case. Therefore, it is possible to provide a motor cooling structure that improves the cooling efficiency while ensuring a sufficient mounting space.

  Furthermore, since the heat sink is made of copper having high thermal conductivity, oil heat can be efficiently transmitted to the power cable. And since a heat sink has a fin shape, the surface area of a heat sink can increase and heat conduction with oil can be performed efficiently.

  Also, if the power cable or terminal block generates heat when starting the motor, etc., that is, if the temperature of the cooling medium is lower than that of the power cable or terminal block, the power cable or terminal block side will move to the cooling medium. Since the heat can be transferred, the power cable can be cooled.

<Modification of the first embodiment>
Hereinafter, with reference to FIG. 4, the cooling structure of the in-wheel motor which concerns on the modification of the 1st Embodiment of this invention is demonstrated.

  The in-wheel motor cooling structure according to this modification is different from the in-wheel motor cooling structure according to the first embodiment described above in that the in-wheel motor includes the terminal block 308, the nut 320, and the oil pipe 200. Instead, a terminal block 336, a nut 334, and an oil pipe 202 are included. Other configurations are the same as the configuration of the in-wheel motor according to the first embodiment described above. The same reference numerals are assigned to the same components. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  As shown in FIG. 4, the terminal 312 is fastened to the terminal mounting portion 318 by a bolt 322 and a nut 334. The nut 334 is formed of a member having a higher thermal conductivity than at least the case 31. In the present embodiment, the material of the nut 334 is, for example, copper. Further, the terminal block 336 communicates with the insertion direction of the bolt 322.

  One end of the oil pipe 202 whose other end is connected to the oil pump 90 passes through the protruding portion 300. The discharge port at one end of the oil pipe 202 is formed to face the nut 334. The shape of the discharge port is not particularly limited. For example, the power cables 302, 304, and 306 may have a plurality of discharge ports that branch toward the respective nuts 334, or oil diffuses from one discharge port toward the respective nuts 334. You may have the discharge outlet which discharges.

  The operation of the cooling structure for the in-wheel motor according to the present modification based on the above structure will be described.

  Oil pumped from the oil pump is discharged from the discharge port through the oil pipe 202. At this time, since the discharge port is provided toward the nut 334, the oil discharged from the discharge port contacts the nut 334. At this time, heat is transferred from the oil to the nut 334. The heat transmitted to the nut 334 is transmitted to each of the power cables 302, 304, and 306 fastened to the nut 334. The heat transmitted to the power cables 302, 304, and 306 is radiated from the power cables 302, 304, and 306 to the atmosphere. The oil after coming into contact with the nut 334 flows into the oil reservoir 120 and is pumped up again by the oil pump 90.

  As described above, according to the motor cooling structure according to this modification, in addition to the same effects as those of the motor cooling structure according to the first embodiment, the terminal of the power cable is fastened to the terminal mounting portion. Since the nut to be used is used, an increase in the number of parts can be suppressed. That is, an increase in cost can be suppressed.

<Second Embodiment>
Hereinafter, a cooling structure for an in-wheel motor according to a second embodiment of the present invention will be described with reference to FIG. In-wheel motor 400 according to the present embodiment includes cases 410A, 410B, and 410C, an oil pump 416, a rotor 430, and a stator 428.

  The case 410A is provided with a terminal block 408 and an oil pipe 412. The case 410B is provided with a rotor 430, a stator 428, and oil passages 414 and 418. The case 410C is provided with an oil pump 416 and oil passages 422 and 424.

  The in-wheel motor 400 is assembled such that the case 410B is sandwiched between the case 410A and the case 410B from the rotation axis direction. At this time, the rotor shaft 432 provided on the rotor 430 is rotatably supported by bearings provided on the case 410A and the case 410C. Oil passage 414 communicates with each of oil passage 422 and oil pipe 412. Further, the oil reservoir 418 communicates with the oil passage 424. In addition, the oil pump 416 is not particularly limited, but in the present embodiment, for example, a gear pump that operates as the rotor shaft 432 rotates is used. When the oil pump 416 is activated, the oil pump 416 pumps up oil from the oil reservoir 418 via the oil passage 424. The oil pump 416 pumps oil to the oil passages 422 and 414 and the oil pipe 412.

  In the terminal block 408 provided in the case 410C, the three power cables 402 are connected to the terminal attachment portions 434, respectively. Terminal attaching portion 434 is connected to U-phase coil, V-phase coil, and W-phase coil wound around stator 428 via connection member 436. The three power cables 402 are conducting wires connected to any of the U-phase coil, V-phase coil, and W-phase coil, respectively. Preferably, power cable 402 is formed of a member having a higher thermal conductivity than at least case 410C. The power cable 402 has a plate-like terminal 406 having an opening at its end. The terminal 406 is fastened to the terminal mounting portion by a bolt 440 and a nut 426. The plate-like terminal 406 is provided so that the heat sink 404 is in contact therewith.

  The heat sink 404 is preferably provided at each of the terminals 406 of the three power cables 402. The heat sink 404 is formed of a member having a higher thermal conductivity than at least the case 410C. In the present embodiment, the material of the heat sink 404 is, for example, copper.

  One end of the oil pipe 412 is connected to the oil passage 414. The discharge port at the other end is provided toward the heat sink 404. The shape of the discharge port is not particularly limited. For example, it may have a plurality of discharge ports that branch toward the respective heat sinks 404 provided at the terminals of the three power cables 402, or diffuse from one discharge port toward the respective heat sinks 404. You may have the discharge outlet which discharges oil.

  The operation of the cooling structure for the in-wheel motor according to the present embodiment based on the above structure will be described. When an alternating current is supplied to each of the three power cables 402, a magnetic field is generated in the stator 428. Then, based on the generated magnetic field, the rotor 430 and the rotor shaft 432 rotate. When the oil pump 416 is operated along with the rotation of the rotor shaft 432, the oil pump 416 pumps oil from the oil reservoir 418 through the oil passage 424. The oil pump 416 discharges the pumped oil toward the oil passage 422. The discharged oil is pumped from the oil passage 422 to the one end of the oil pipe 412 through the oil passage 414. Then, the oil is discharged from a discharge port provided at the other end of the oil pipe 412. Since the discharge port is provided toward the heat sink 404, the oil discharged from the discharge port contacts the heat sink 404. At this time, heat is transferred from the oil to the heat sink 404. The heat transferred to the heat sink 404 is transferred to the power cable 402 via the terminal 406 of the power cable 402 provided so as to be in contact with the heat sink 404. The heat transmitted to the power cable 402 is radiated from the power cable 402 to the atmosphere. The oil after contacting the heat sink 404 flows into the oil reservoir 418 and is pumped up again by the oil pump 416.

  As described above, the electric motor cooling structure according to the present embodiment has the same effect as the electric motor cooling structure according to the first embodiment described above.

<Modification of Second Embodiment>
Hereinafter, with reference to FIG. 6, the cooling structure of the in-wheel motor which concerns on the modification of the 2nd Embodiment of this invention is demonstrated.

  The in-wheel motor cooling structure according to this modification includes an oil pipe 420 and an oil passage 438 instead of the oil pipe 412 as compared with the in-wheel motor cooling structure according to the second embodiment described above. . Other configurations are the same as the configuration of the in-wheel motor according to the second embodiment described above. The same reference numerals are assigned to the same components. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  One end of the oil pipe 420 is connected to the oil passage 438. The discharge port at the other end of the oil pipe 200 is provided toward the nut 426. Oil passage 438 is connected to oil passage 414 when case 410A and case 410B are assembled. The shape of the discharge port is not particularly limited. For example, it may have a plurality of discharge ports that branch toward the respective nuts 426 provided on the three power cables 402, or oil is diffused from one discharge port toward the respective nuts 426. You may have the discharge outlet which discharges.

  The nut 426 is formed of a member having a higher thermal conductivity than at least the casing. In the present embodiment, the material of the nut 426 is copper.

  The operation of the cooling structure for the in-wheel motor according to the present embodiment based on the above structure will be described. When an alternating current is supplied to each of the three power cables 402, a magnetic field is generated in the stator 428. Then, based on the generated magnetic field, the rotor 430 and the rotor shaft 432 rotate. When the oil pump 416 is operated along with the rotation of the rotor shaft 432, the oil pump 416 pumps oil from the oil reservoir 418 through the oil passage 424. The oil pump 416 discharges the pumped oil toward the oil passage 422. The discharged oil is pumped from the oil passage 422 to one end of the oil pipe 420 via the oil passage 414 and the oil passage 438. Then, the oil is discharged from a discharge port provided at the other end of the oil pipe 420. Since the discharge port is provided toward the nut 426, the oil discharged from the discharge port contacts the nut 426. At this time, heat is transferred from the oil to the nut 426. The heat transferred to the nut 426 is transferred to the power cable 402 through the terminal 406 of the power cable 402 provided so as to be in contact with the nut 426. The heat transmitted to the power cable 402 is radiated from the power cable 402 to the atmosphere. The oil after coming into contact with the nut 426 flows into the oil reservoir 418 and is pumped up again by the oil pump 416.

  As described above, the electric motor cooling structure according to this modification has the same effect as the electric motor cooling structure according to the above-described modification of the first embodiment.

  In the present embodiment, the mode in which oil is used as the cooling medium has been described. However, there is no particular intention to limit the oil to fluid. That is, even for a motor having a cooling structure in which the inside of the motor is cooled by convection or forced circulation of gas such as air, the structure for releasing heat from the power cable (power transmission means) that is the technical idea of the present invention is Applicable.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic sectional drawing of the electric wheel provided with the in-wheel motor which concerns on 1st Embodiment. It is an external view of the in-wheel motor which concerns on 1st Embodiment. It is sectional drawing of the terminal block provided in the case of the in-wheel motor which concerns on 1st Embodiment. It is sectional drawing of the terminal block provided in the case of the in-wheel motor which concerns on the modification of 1st Embodiment. It is a schematic sectional drawing of the in-wheel motor which concerns on 2nd Embodiment. It is a schematic sectional drawing of the in-wheel motor which concerns on the modification of 2nd Embodiment.

Explanation of symbols

  1-5 screw, 6-8 arrow, 10 wheel disc, 10A low part, 10B cylindrical part, 20 hub, 30, 31, 410A, 410B, 410C case, 30A low part, 30B side face part, 30C inclined part, 30D Joint, 40 Brake rotor, 50 Brake caliper, 50A opening, 51 Brake piston, 52, 53 Brake pad, 60 Motor, 61 Stator core, 62 Stator coil, 62A, 62B Coil end, 63, 430 Rotor, 64, 432 Rotor Shaft, 71-76 bearing, 80 planetary gear, 81 sun gear shaft, 82 sun gear, 83 pinion gear, 84 planetary carrier, 85 ring gear, 90,416 oil pump, 100 motor wheel, 110 shaft, 111, 121, 130, 414, 422, 424, 438 Oil passage, 112 Oil hole, 120, 418 Oil reservoir, 140 Tire, 200, 202, 412, 420 Oil pipe, 300, 326 Protruding part, 302, 304, 306, 402 Power cable, 308 , 336, 408 terminal block, 310, 312, 314, 406 terminal, 316, 318, 320, 434 terminal mounting part, 322, 328, 440 bolt, 324, 334, 426 nut, 330, 404 heat sink, 332, 436 connection Member, 400 in-wheel motor, 428 stator.

Claims (5)

A cooling structure for an electric motor provided with a cooling medium passage for circulating a cooling medium in a housing that houses the electric motor,
Formed of a member having a higher thermal conductivity than at least the casing, and a power transmission means for supplying power to the electric motor;
Look containing a heat transfer means for transferring heat to said power transmission means from the cooling medium,
The cooling structure for an electric motor , wherein the heat transfer means is formed of a member having a higher thermal conductivity than at least the casing . The cooling structure further includes a connection member that is provided in the housing and connects the power transmission unit and the electric motor.
The heat transfer means is a heat radiating member provided in the housing so as to be in contact with the power transfer means in the connection member,
The cooling structure for an electric motor according to claim 1, wherein the cooling medium passage has a discharge port that discharges the cooling medium toward the heat radiating member.   The motor cooling structure according to claim 2, wherein the heat radiating member is a member having a fin shape. The cooling structure further includes a connection member that is provided in the housing and connects the power transmission unit and the electric motor.
The heat transfer means is a fixing member that is provided in the housing and fixes the power transmission means and the connection member,
The electric motor cooling structure according to claim 1, wherein the cooling medium passage has a discharge port that discharges the cooling medium toward the fixing member. The electric motor is a drive motor provided in a wheel of a vehicle, the cooling structure of the electric motor according to claim 1.

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