JP2009136078A - Motor cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor cooling structure wherein leakage of oil from an oil passage can be avoided when a wheel is removed from a rotating member. <P>SOLUTION: The motor cooling structure includes: a casing attached to a vehicle body through a suspension; an electric motor provided in the casing; the rotating member so provided that power can be transmitted between it and the electric motor; wheels configured to rotate integrally with the rotating member and removably from the rotating member; a braking mechanism that is attached to the casing and applies braking force to the wheels through the rotating member; a lubricated part provided in the casing and cooled or lubricated with oil; and a heat exchange unit that causes heat exchange between oil supplied to the lubricated part and air to cool the oil. The heat exchange unit is provided in the rotating member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor cooling structure provided with an electric motor for driving wheels of a vehicle and capable of cooling the electric motor.

  In general, the wheels of a vehicle are supported by a vehicle body via a suspension device. On the other hand, a vehicle using an electric motor as a power source for transmitting power to wheels is known, and a configuration in which the electric motor is supported by a vehicle body via a suspension device together with the wheels is known. Thus, when the wheel and the electric motor are both supported by the vehicle body with the suspension device interposed therebetween, the electric motor is called an in-wheel motor. An example of such an in-wheel motor is described in Patent Document 1. In the in-wheel motor described in Patent Document 1, an electric motor is provided in a housing, and the electric motor has a rotor and a stator. A reduction gear is connected to the rotor so that power can be transmitted. A shaft is connected to the speed reducer so that power can be transmitted. An annular hub is attached to the shaft, and wheels are attached to the hub so as to rotate together. This wheel has a disk-shaped wheel and a tire, and the hub and the wheel are fixed by a stud bolt and a nut.

  On the other hand, an oil pump is provided in the casing, and is configured to be oil-driven by the driving force of the electric motor. When the oil pump is driven, the oil in the casing is sucked, and the oil discharged from the oil pump is supplied to the lubricated part in the casing. The lubricated portion is a mechanism that is cooled or lubricated by oil. The lubricated portion includes a bearing that supports the shaft, a meshing portion of gears constituting the reduction gear, a heat generating portion of the electric motor, and the like. A cooling mechanism for cooling the oil is provided in the oil supply path from the discharge port of the oil pump to the lubricated part. The cooling mechanism is provided in the shaft, the first oil passage provided in the direction along the axis that is the rotation center of the shaft, the second oil passage and the third oil passage provided in the wheel, and the wheel, And it has the heat exchange part (oil chamber) connected to the 2nd oil path. The second oil passage is formed radially on the wheel. And the 1st oil path and the 2nd oil path are connected in the state where the wheel was attached to the shaft. Furthermore, the 3rd oil path is connected to the heat exchange part.

  In such a configuration, the oil discharged from the oil pump is sent to the heat exchange unit via the first oil passage and the second oil passage. And by rotation of a wheel, in a heat exchange part, the heat of oil is dissipated in the air via a wheel. That is, heat exchange is performed between oil and air. The oil thus cooled is returned to the inside of the casing via the third oil passage and supplied to the lubricated portion. An example of a cooling device used for an in-wheel motor is also described in Patent Documents 2 to 4.

JP-A-2005-67416 Japanese Patent Laid-Open No. 61-189871 JP-A-9-133167 JP 2007-147204 A

  However, in the in-wheel motor described in Patent Document 1, a heat exchange unit that performs heat exchange between oil and air is provided in the wheel. For this reason, when the wheel is removed from the shaft in order to repair or replace the wheel, the oil passage provided in the shaft is separated from the oil passage provided in the wheel, and the opening of each oil passage is in the atmosphere. It will be exposed. For this reason, in order to prevent oil from leaking from the oil passage, an oil leakage prevention mechanism must be provided, which may complicate the structure.

  The present invention has been made paying attention to the above technical problem, and an object of the present invention is to provide a motor cooling structure capable of suppressing the complicated structure of the oil leakage prevention mechanism.

  In order to achieve the above object, a first aspect of the present invention provides a casing attached to a vehicle body via a suspension device, an electric motor provided inside the casing, and a power transmission to the electric motor. A rotating member, a wheel that can be attached to and removed from the rotating member, a braking mechanism that is attached to the casing and applies a braking force to the wheel via the rotating member, A lubricated portion provided in the casing and cooled or lubricated by oil, and a heat exchanging portion that cools the oil by exchanging heat between the oil and air supplied to the lubricated portion. In the motor cooling structure, the heat exchanging portion is provided in the rotating member.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, an oil pump that is driven by the power of the electric motor and sucks and discharges oil is provided, and the rotating member has a power of the electric motor. A first rotating member that is transmitted; and a second rotating member that is attached to an outer periphery of the first rotating member and that rotates integrally with the first rotating member. A friction member that generates a braking force in contact with the member, the heat exchanging portion is provided in the second rotating member, and the oil discharged from the oil pump passes therethrough and the heat An oil passage connected to the exchange part is provided in the first rotating member.

  According to a third aspect of the invention, in addition to the configuration of the second aspect, when the temperature of the rotating member is relatively high, the oil passage is blocked, while the temperature of the rotating member is relatively low. And a switching mechanism for opening the oil passage.

  According to a fourth aspect of the present invention, in addition to the configuration of the second aspect, the valve body that opens and closes the oil passage, and the temperature of the rotating member are extended when the temperature of the rotating member is relatively high. Is provided with a switching mechanism having a temperature-sensitive deformation member that contracts when the oil temperature is relatively low and applies force to the valve body in the direction of closing the oil passage. is there.

  According to a fifth aspect of the present invention, in addition to the configuration of the second aspect, the braking mechanism is configured such that a braking force is controlled by hydraulic pressure, and the hydraulic pressure for controlling the braking force of the braking mechanism is relatively high. A switching mechanism that opens the oil passage when the oil pressure that controls the braking force of the braking mechanism is relatively low while blocking the oil passage is provided.

  According to a sixth aspect of the invention, in addition to the configuration of the fifth aspect, the switching mechanism includes a valve body that opens and closes the oil passage, and a cylinder chamber in which the valve body is disposed and hydraulic pressure is applied to the valve body. And a throttle portion configured to have a smaller area in a plane perpendicular to the oil flow direction of the oil passage than a pressure receiving area in which hydraulic pressure acts on the valve body in the cylinder chamber. It is.

  According to a seventh aspect of the invention, in addition to the configuration of the second aspect, the oil passage is blocked when the rotational speed of the rotating member is relatively high, while the rotational speed of the rotating member is relatively low. It has the switching mechanism which opens an oil path, It is characterized by the above-mentioned.

  In addition to the configuration of claim 2, the invention of claim 8 blocks the oil passage when the centrifugal force generated by the rotation of the rotating member is relatively weak, while the centrifugal force generated by the rotation of the rotating member is It has a switching mechanism that opens the oil passage when it is relatively strong.

  According to the first aspect of the invention, the power of the electric motor is transmitted to the wheels via the rotating member. Further, the braking mechanism applies a braking force to the wheel via the rotating member. Further, in the casing, the lubricated part is cooled and lubricated by the oil. Moreover, the heat exchange part which performs heat exchange between oil and air is provided in the rotating member. For this reason, even when the wheel is removed from the rotating member, oil leakage does not occur from the heat exchange unit. Therefore, it is possible to avoid a complicated structure of the mechanism that prevents oil from leaking from the heat exchange section.

  According to the invention of claim 2, in addition to the same effect as that of the invention of claim 1, the oil pump is driven by the power of the electric motor, the oil is sucked into the oil pump, and the oil from the oil pump Is discharged. Further, the braking mechanism causes the friction member to contact the second rotating member to generate a braking force. Furthermore, the oil discharged from the oil pump passes through the oil passage to the heat exchange unit, where heat is exchanged between the oil and the air.

  According to the invention of claim 3, in addition to obtaining the same effect as that of the invention of claim 2, the switching mechanism shuts off the oil passage when the temperature of the rotating member is relatively high, while the rotating member When the temperature of the oil is relatively low, the oil passage is opened. Therefore, when the temperature of the rotating member is relatively high, the oil is not sent to the heat exchange unit, and the heat of the rotating member can be prevented from being transmitted to the oil.

  According to the invention of claim 4, in addition to the same effect as that of the invention of claim 2, the shape of the temperature-sensitive deformation member is changed by the temperature change of the rotating member, the valve body is operated, and the oil passage is opened. Or blocked.

  According to the invention of claim 5, in addition to obtaining the same effect as that of the invention of claim 2, the braking force of the braking mechanism is controlled by hydraulic pressure. Further, when the hydraulic pressure that controls the braking force of the braking mechanism is relatively high, the oil path is blocked by the switching mechanism. On the other hand, when the hydraulic pressure for controlling the braking force of the braking mechanism is relatively low, the oil path is opened by the switching mechanism.

  According to the invention of claim 6, in addition to obtaining the same effect as that of the invention of claim 5, the area of the throttle portion is narrower than the area of the cylinder chamber, so that the oil pressure of the oil passage increases. The time for the oil in the cylinder chamber to return to the throttle is relatively delayed.

  According to the seventh aspect of the invention, in addition to obtaining the same effect as the second aspect of the invention, the oil passage is blocked by the switching mechanism when the rotational speed of the rotating member is relatively high. On the other hand, when the rotational speed of the rotating member is relatively low, the oil passage is opened by the switching mechanism.

  According to the invention of claim 8, in addition to obtaining the same effect as that of the invention of claim 2, when the centrifugal force generated by the rotation of the rotating member is relatively weak, the oil path is blocked by the switching mechanism. On the other hand, when the centrifugal force generated by the rotation of the rotating member is relatively strong, the oil path is opened by the switching mechanism.

  The in-wheel motor according to the present invention can be used for a vehicle wheel. Here, the present invention can be applied regardless of whether the suspension device that supports the wheels is of the strut type, the double wishbone type, the swing arm type, or the multi-link type. That is, it is possible to use an independent suspension device in which the left and right wheels operate independently in the vertical direction. The vehicle body in the present invention forms an indoor space, and may be either a monocoque type without a frame or a frame type with a frame. The in-wheel motor in this invention can be applied to either the front wheel or the rear wheel of the vehicle. In this invention, the wheel is attached to the rotating member by a fixing mechanism, and the fixing mechanism is configured to be able to remove the wheel from the rotating member. As the fixing mechanism, a combination of a stud bolt and a nut, or a single bolt can be used. In the present invention, the electric motor can use a motor generator that has both a power running function for converting electrical energy into kinetic energy and a regeneration function for converting kinetic energy into electrical energy. The casing in this invention has a function of storing the electric motor and storing oil, and can prevent the oil in the casing from leaking outside the casing. In the present invention, the oil pump may be disposed inside or outside the casing. Furthermore, in this invention, the rotating member is a power transmission member provided in a power transmission path between the electric motor and the wheels. The rotating member includes a rotating shaft, a gear, a connecting drum, a hub, a disk, a plate, and the like. This rotating member may be rod-shaped or annular. The term “relative” in the present invention does not mean comparison with a specific comparison target or reference value, and the higher the rotation speed, oil temperature, oil pressure, centrifugal force, etc., which are parameters, It means lower or weaker. That is, it does not mean a specific rotational speed, oil temperature, oil pressure or centrifugal force.

  In this invention, the member to be lubricated is an element or mechanism that is cooled or lubricated by oil (lubricating oil). The lubricated member includes a meshing portion between gears, a contact portion between rollers, a rolling portion of a rolling element in a bearing, a stator of an electric motor, and the like. That is, the member to be lubricated includes an element that generates heat or a temperature rise or seizure due to a frictional force or a meshing force, and further includes an element that increases the temperature when energized. The braking mechanism in the present invention includes a mechanism that converts frictional force into braking force, or a mechanism that converts electromagnetic force into braking force. The oil passage in the present invention is a passage through which oil passes, and includes a flow passage or a port (opening) of a valve in addition to a flow passage, a hole, a groove, a concave portion, or a depression provided in the rotating member. The first rotating member and the second rotating member in the present invention are physically separate components, and are fixed to each other so that the first rotating member and the second rotating member rotate integrally. And the sealing device which prevents that oil leaks is provided between the 1st rotation member and the 2nd rotation member. Specifically, an O-ring made of an elastomer can be used as the sealing device.

  Next, a specific example of the in-wheel motor according to the present invention will be described with reference to the drawings. 2 is a schematic longitudinal sectional view when the wheel 1 is viewed from the front, and FIG. 3 is a specific sectional view of FIG. The wheel 1 is supported by a vehicle body 3 with a suspension device 2 interposed. The wheel 1 may be either a front wheel or a rear wheel of the vehicle, and the suspension device 2 that supports the wheel 1 may be either a strut type, a double wishbone type, a swing arm type, or a multilink type. The vehicle body 3 and the casing 4 are connected by the suspension device 2. An electric motor 7 is provided inside the casing 4, and wheels 1 driven by the electric motor 7 are provided.

  The wheel 1 is disposed outside the casing 4, and the wheel 1 includes an annular wheel 8 and a tire 9 attached to the outer periphery of the wheel 8. The outer periphery of the tire 9 contacts the road surface 42 as shown in FIG. The wheel 8 includes a disc-shaped portion 10 formed along the height direction of the vehicle body 3 and a cylindrical portion 11 formed continuously from the outer periphery of the disc-shaped portion 10 and extending substantially in the horizontal direction. And have. A casing 4 is disposed inside the cylindrical portion 11. The casing 4 is attached to the vehicle body 3 via the upper arm 13 and the lower arm 14. The lower arm 14 is connected to the vehicle body 3 via a shock absorber (not shown). A coil spring (not shown) is provided between the vehicle body 3 and the lower arm 14. This coil spring can be expanded and contracted in the vertical direction of the vehicle body 3. The suspension device 2 is configured by the upper arm 13, the lower arm 14, the shock absorber, and the coil spring configured as described above. The suspension device 2 shown in FIG. 2 is a double wishbone type suspension device.

  The casing 4 is configured to be hollow, and an electric motor 7 is provided inside the casing 4. As the electric motor 7, a direct current motor or an alternating current motor can be used. For example, a three-phase alternating current motor / generator can be used. For this reason, the electric motor 7 can perform power running control in which electric power is supplied and driven as an electric motor, and regenerative control that converts kinetic energy into electric power. The electric motor 7 has a stator 17 and a rotor 18. The stator 17 is fixed to the casing 4 and cannot be rotated. Further, the rotor 18 is rotatable inside the casing 4. The vehicle body 3 is provided with a power supply 78, and the power supply 78 and the electric motor 7 are connected by an electric circuit (not shown). That is, power can be exchanged between the power supply 78 and the electric motor 7. When electric power is supplied to the electric motor 7 and driven as an electric motor, torque output from the electric motor 7 can be transmitted to the wheels 1.

  The configuration of the power transmission path from the rotor 18 of the electric motor 7 to the wheel 1 will be described. A cylindrical hollow shaft 19 is connected to the rotor 18. That is, the rotor 18 is configured to rotate integrally with the hollow shaft 19. Further, a speed reducer 20 is provided in the power transmission path between the hollow shaft 19 and the wheels. The reduction gear 20 is disposed inside the casing 4, and the reduction gear 20 is constituted by a gear transmission, specifically, a single pinion type planetary gear mechanism. That is, it has a sun gear 21 and a ring gear 22 arranged on the same axis, a pinion gear 23 meshed with the sun gear 21 and the ring gear 22, and a carrier 24 that supports the pinion gear 23 so that it can rotate and revolve. The sun gear 21 is formed on the outer peripheral surface of the hollow shaft 19. Further, the ring gear 22 is fixed to the casing 4, and the ring gear 22 cannot rotate.

  Further, the carrier 24 is rotatably supported by the casing 4 with bearings 25 and 26 interposed therebetween. The hollow shaft 19 is rotatably supported by the casing 4 with the bearing 27, the carrier 24, and the bearing 26 interposed therebetween. The sun gear 21 and the carrier 24 constituting the speed reducer 20 have a rotation center at the axis B1, and the rotor 18 is also configured to be rotatable around the axis A1. Further, a rotating shaft 28 that rotates integrally with the carrier 24 is provided. An annular hub 29 is attached to the outer periphery of the rotating shaft 28. More specifically, the rotating shaft 28 and the hub 29 are splined or serrated. Further, a flange 50 is provided on the outer periphery of the rotary shaft 28, and a female screw 51 is formed on the rotary shaft 28. A nut 52 is attached to the female screw 51, and the nut 52 is tightened to fix the hub 29 to the outer periphery of the rotary shaft 28. That is, the hub 29 is positioned and fixed in the direction along the axis B <b> 1 by being sandwiched between the flange 50 and the nut 52. A hub 29 is rotatably supported by the casing 4 with a bearing 30 interposed therebetween. Thus, the rotating shaft 28 is also configured to be rotatable about the axis B1.

  Next, the mounting structure of the wheel 1 will be described. A plurality of stud bolts 53, specifically, four stud bolts 53 are fixed to the hub 29. The four stud bolts 53 are arranged at the same interval on the circumference centered on the axis A1. Further, four shaft holes 54 are formed in the wheel 8, and stud bolts 53 are inserted into the shaft holes 54. A nut 55 is attached to the stud bolt 53, and the nut 55 is tightened. Thus, the wheel 1 is fixed to the hub 29, and the wheel 1 is configured to rotate integrally with the rotary shaft 28. When the nut 55 is loosened and removed from the stud bolt 53, the wheel 1 can be removed from the hub 29. Further, when the wheel 1 is attached to the hub 29 and the nut 55 is tightened, the wheel 1 can be fixed to the hub 29. Thus, the wheel 1 is configured to be detachable from the hub 29.

  Further, a braking mechanism that applies a braking force to the wheel 1 will be described. A disc-shaped plate 56 is fixed to the outer periphery of the hub 29. The rotor 32 is attached to the outer peripheral end of the plate 56. The rotor 32 has a disk shape. The hub 29, the plate 56, and the rotor 32 thus configured are configured to rotate integrally. On the other hand, a disk caliper 33 is attached to the outside of the casing 4. The disc caliper 33 has a hydraulic chamber 34 and brake pads 35 and 36. On the other hand, the vehicle body 3 is provided with a brake pedal 75. The brake pedal 75 is operated by an occupant of the vehicle, and the vehicle body 3 is provided with a master cylinder 76 that converts the pedaling force applied to the brake pedal 75 into hydraulic pressure.

  Further, an oil passage 77 that connects the master cylinder 76 and the hydraulic chamber 34 is provided, and the oil passage 77 is connected to the hydraulic chamber 34. The oil passage 77 is formed by a metal tube (not shown) and a flexible hose (not shown) mainly made of a rubber material. The oil passage 77 is provided with a solenoid valve (not shown) for controlling the hydraulic pressure. Then, the hydraulic pressure in the hydraulic chamber 35 is controlled based on the pedaling force applied to the brake pedal 75. Then, the force that presses the brake pad 35 against the other brake pad 36 changes, the rotor 32 is sandwiched between the brake pads 35 and 36, and a braking force that is transmitted to the wheel 1 is generated. Thus, the disc caliper 33, the brake pads 35 and 36, and the hydraulic chamber 34 constitute a part of a braking mechanism that controls the braking force applied to the wheel 1. The rotor 32 is made of a metal material having thermal conductivity, such as gray cast iron or stainless steel.

  Furthermore, a lubricated portion is provided inside the casing 4. The portion to be lubricated includes a meshing portion of gears constituting the reduction gear 20, a sliding portion of the bearings 25, 26, 27, and 30, a heat generating portion of the electric motor 7, and the like. The lubricated part is an element, mechanism, or part that generates heat, wear, seizure, etc., and the lubricated part is lubricated and cooled by oil (lubricating oil). Next, a fluid machine that supplies oil to be supplied to these parts to be lubricated will be described. In this specific example, an oil pump 31 is provided as a fluid machine. The oil pump 31 is provided inside the casing 12. The oil pump 31 is a rotary oil pump, and a rotor (not shown) is connected to the carrier 24 so that power can be transmitted.

(First specific example)
Next, a “first specific example” of the cooling structure of the present invention will be described with reference to FIG. As shown in FIG. 1, the oil pump 31 has a suction port 57 and a discharge port 58. An oil reservoir 59 is formed in the casing 4, and the oil reservoir 59 and the suction port 57 are connected by an oil passage 60. The rotary shaft 28 is provided with oil passages 61 and 62 in the direction along the axis B1. The oil passages 61 and 62 are formed by cutting a metal material constituting the rotary shaft 28. One end of the oil passage 61 is opened at the end of the rotating shaft 28 or the outer peripheral surface, and the discharge port 58 is connected to the opening. The other end of the oil passage 61 is opened on the outer peripheral surface of the rotary shaft 28. Furthermore, one end of the oil passage 62 is opened at the end of the rotating shaft 28 or the outer peripheral surface, and the lubricated portion 64 is connected to the opening through the oil passage 63. The lubricated portion 64 is connected to an oil reservoir 59 via an oil passage 65. The oil passages 63 and 65 are passages through which oil can pass, and the oil passages 63 and 65 can be configured by holes, depressions, ports, through holes, grooves, and the like provided inside the casing 4.

  The other end of the oil passage 62 is opened on the outer peripheral surface of the rotary shaft 28, and an oil passage 66 connecting the oil passage 61 and the oil passage 62 extends over the hub 29, the plate 56, and the rotor 32. Is formed. That is, the oil passage 66 extends outward in the radial direction from the outer peripheral surface of the rotating shaft 28, and the oil passage 66 is folded back into a shape that makes a U-turn from the inner peripheral side to the outer peripheral side of the rotor 32. The end of the folded oil passage 66 is connected to the oil passage 62. Since the oil passage 66 is continuously formed in the hub 29, the plate 56, and the rotor 32, the hub 29, the plate 56, and the rotor 32 are shown as a single component for convenience in FIG. . The hub 29, the plate 56, and the roller 32 are all made of a metal material. The metal material is cut to form a hole, and the hole is an oil passage 60.

  An O-ring 67 is provided between the inner peripheral surface of the hub 29 and the outer peripheral surface of the rotary shaft 28. The O-ring 67 is formed in an annular shape, and the O-ring 67 is integrally formed from an elastomer. The O-ring 67 prevents oil from leaking from the connecting portion between the oil passage 61 and the oil passage 66 or the connecting portion between the oil passage 62 and the oil passage 66. That is, the oil passage 66 is not open or exposed to the atmosphere. In particular, the oil passage 66 is not opened between the contact surfaces of the hub 29 and the wheel 8. In this manner, the oil circulation path (oil circulation circuit) is constituted by the oil reservoir 59, the oil pump 31, the oil path 61, the oil path 66, the oil path 62, the oil path 63, the lubricated portion 64, and the oil path 65. It is configured. In FIG. 1, for the sake of convenience, the oil passage 66 is folded back in a U shape in a plane along the axis B1, but the oil passage 66 has a shape folded in a plane perpendicular to the axis B1. You may do it. In addition, the oil passages 61 and 62 and the oil passage provided in the casing 4 are connected to each other when the rotary shaft 28 is rotating or stopped. Since this configuration is well known, a description thereof will be omitted.

  Next, devices and elements provided in the vehicle body 1 will be described. The vehicle body 3 is provided with a power source 78, and the power source 78 includes a power storage device. This power storage device is a secondary battery that can be charged and discharged, and a battery or a capacitor can be used as the secondary battery. Further, the power source 78 may include a fuel cell. A fuel cell is a generator that generates an electromotive force by a reaction between hydrogen and oxygen. The vehicle body 3 is provided with an electronic control device (not shown). The electronic control device includes a sensor or switch for detecting a shift position, a vehicle speed, an acceleration request, a deceleration request, the number of rotations of each wheel, and the like. Signal is input. Further, a signal for controlling the torque and the rotational speed of the electric motor 7 is output from the electronic control unit.

  In the vehicle configured as described above, when the accelerator pedal is depressed and an acceleration request is generated, electric power is supplied from the power storage device to the electric motor 7. When the electric motor 7 is driven, the torque is transmitted to the sun gear 21. Then, the ring gear 22 functions as a reaction force element, and torque is output from the carrier 24. That is, the reduction gear 20 has the sun gear 21 as an input element and the carrier 24 as an output element. Further, since the rotational speed of the carrier 24 is lower than the rotational speed of the sun gear 21, the torque of the electric motor 7 is amplified and transmitted to the carrier 24. The torque transmitted to the carrier 24 is transmitted to the wheel 1 via the rotating shaft 28, and a driving force is generated at the wheel 1. When the brake pedal 75 is depressed or the accelerator pedal is returned and a deceleration request is generated, the kinetic energy of the vehicle is transmitted from the wheel 1 to the electric motor 7, so that the electric motor 7 is activated as a generator. If this is done, regenerative braking force is generated. The electric power generated by the electric motor 7 can be charged in the power storage device. Further, when the brake pedal 75 is depressed, the hydraulic pressure in the hydraulic chamber 34 is increased, the clamping pressure between the brake pads 35 and 36 is increased, and the braking force applied to the wheel 1 is increased.

  By the way, when the oil pump 31 is driven by the torque of the carrier 24, the oil in the oil reservoir 59 is sucked into the suction port 57 of the oil pump 31, and the oil is discharged from the discharge port 58 of the oil pump 31 to the oil passage 61. Is done. The oil discharged to the oil passage 61 is sent to the oil passage 62 via the oil passage 66. The oil in the oil passage 62 is sent to the lubricated portion 64 via the oil passage 63, and the lubricated portion 64 is cooled and lubricated by the oil. Specifically, in the gear transmission that constitutes the speed reducer 20, the meshing portion between the gears generates heat. Further, in the bearings 25, 26, 27, and 30, the rolling portion of the rolling element generates heat. Furthermore, the stator 17 of the electric motor 7 generates heat when energized. These heating elements are cooled by oil. Here, the heat of the elements constituting the lubricated portion 64 is transmitted to the oil, the temperature of the oil rises, and the oil returns to the oil reservoir 59 via the oil passage 65.

  Thereafter, the oil in the oil reservoir 59 repeats the action of circulating through the “oil circulation path”. In this specific example, when the oil passes through the oil passage 66, the heat of the oil is transmitted to the rotor 32, and the heat of the rotor 32 is radiated into the atmosphere. In this manner, the oil passage 66 and the rotor 32 function as a heat exchanger, whereby the oil passing through the oil passage 66 is cooled. In this specific example, the oil passage 66 itself and the oil passages 61 and 62 connected to the oil passage 66 are provided on the rotating shaft 28, and are not formed on the wheel 8. Therefore, when the nut 55 is loosened and the wheel 1 is removed, the oil in the oil passages 61, 62, 66 does not leak to the outside of the oil passage. Furthermore, it is not necessary to provide a sealing device that prevents oil leakage that occurs when the wheel 1 is removed.

  Further, in the first specific example shown in FIG. 1, since the braking force of the wheel 1 can be generated by the regenerative control of the electric motor 7, the brake pads 35 and 36 are pressed against the rotor and controlled by the frictional force. The frequency of generating power is reduced. As a result, the temperature of the brake pads 35 and 36 does not easily rise, but when the heat of the oil in the oil passage 66 is dissipated into the atmosphere via the rotor 32, the heat is also transmitted to the brake pads 35 and 36. Is done. Therefore, it is possible to prevent the brake pads 35 and 36 from being excessively cooled.

  On the other hand, when the temperature of the rotor 32 is higher than the temperature of the oil flowing through the oil passage 66, the heat of the rotor 32 is transmitted to the oil flowing through the oil passage 66, and the temperature of the oil rises. The oil warmed in this way is supplied to the lubricated portion 64 via the oil passages 62 and 63 and returned to the oil reservoir 59. For this reason, the internal mechanism of the casing 4 can be warmed up relatively early, and an increase in the viscosity of the oil can be avoided. Therefore, an increase in power loss of the electric motor 7 due to driving of the oil pump 31 can be suppressed. In other words, it is relatively easy to ensure the power to be transmitted from the electric motor 7 to the wheel 1.

  The first specific example 1 is a specific example corresponding to claim 1 and claim 2, and the correspondence between the first specific example and the configuration of the present invention will be described. The suspension device 2 corresponds to the suspension device of the present invention, the casing 4 corresponds to the casing of the present invention, the electric motor 7 corresponds to the electric motor of the present invention, the rotary shaft 28 and the hub. 29, the plate 56, and the rotor 32 correspond to the rotating member of the present invention, and the wheel 1 corresponds to the wheel of the present invention. The disc caliper 33, the hydraulic chamber 34, and the brake pads 35, 36 correspond to the braking mechanism in the present invention, the lubricated portion 64 corresponds to the lubricated portion of the present invention, and the oil passage 66 and the rotor 32 include It corresponds to the heat exchange part in this invention. The oil pump 31 corresponds to the oil pump in the present invention, the rotating shaft 28 corresponds to the first rotating member in the present invention, and the hub 29, the plate 56 and the rotor 32 correspond to the second rotating member in the present invention. The brake pads 35 and 36 correspond to the friction members in the present invention.

(Second specific example)
Next, a “second specific example” of the cooling structure of the present invention will be described with reference to the schematic diagram of FIG. In the configuration of FIG. 4, the same components as those of FIG. 1 are denoted by the same reference numerals as in FIG. In the second specific example, a switching mechanism 68 is provided between the oil passage 61 and the oil passage 66. The switching mechanism 68 has a function of cutting off the connection between the oil passage 61 and the oil passage 66 and a function of connecting the oil passage 66 and the oil passage 61. In the second specific example, an annular member 73 is fixed to the outer periphery of the rotary shaft 28 instead of the flange 50. The annular member 73 is constituted by a member different from the metal material constituting the rotary shaft 28, and the annular member 73 and the rotary shaft 28 are integrally rotated. The annular member 73 is made of a metal material having thermal conductivity, for example, aluminum or an aluminum alloy. The end surface of the annular member 73 is in contact with the hub 29. For this reason, heat transfer is possible between the hub 29 and the annular member 73.

  The annular member 73 is provided with a cylinder chamber 69. The cylinder chamber 69 is provided at one place in the circumferential direction of the annular member 73. The cylinder chamber 69 has a depth in the radial direction with the axis B1 as the center. A valve body 70 is disposed in the cylinder chamber 69. The valve body 70 has a configuration capable of operating in the depth direction of the cylinder chamber 69, specifically a disc shape or a columnar shape. A compression coil spring 71 is disposed between the outer peripheral surface of the rotating shaft 28 and the valve body 70 in the cylinder chamber 69. Due to the elastic force of the compression coil spring 71, the valve body 70 is pressed outward in the radial direction of the rotary shaft 28 about the axis B1. The annular member 73 is provided with a port 74. The port 74 passes through the annular member 73 in a direction along the axis B1. The port 74 connects the cylinder chamber 69 and one end of the oil passage 66.

  On the other hand, a spring 72 is disposed outside the valve body 70 in the cylinder chamber 69 in the radial direction of the rotary shaft 28 around the axis B1. The spring 72 has a characteristic that its shape changes due to a temperature change, specifically, a characteristic that it expands and contracts in the radial direction of the rotary shaft 28. The spring 72 maintains a contracted shape when the temperature is relatively low. On the other hand, when the temperature is relatively high, the spring 72 has a stretched shape. As a material satisfying the mechanical characteristics of the spring 72, a bimetal or a shape memory member can be used. The bimetal is a combination of two metals having different coefficients of thermal expansion, and an aluminum alloy bimetal or a copper alloy bimetal can be used. The shape memory member changes its shape at the transformation temperature, and a shape memory alloy or a shape memory resin can be used as the shape memory member. As the shape memory alloy, a Ni-ti alloy or a Cu-Zn-Al alloy can be used. Furthermore, as the shape memory resin, a polyisoprene-based or styrene-butadiene copolymer can be used.

  Next, the operation of the second specific example will be described. In the second specific example, the same operational effects as those of the first specific example can be obtained for the same components as those of the first specific example. Further, when the brake pads 35 and 36 are pressed against the rotor 32 and a braking force is applied to the wheel 1, frictional heat is generated by sliding between the brake pads 35 and 36 and the rotor 32. The heat is transmitted from the rotor 32 to the hub 29 via the plate 56. In the second specific example, the shape of the spring 72 changes due to the heat of the hub 29. Here, in either case where the spring 72 has a contracted shape or an extended shape, a force is generated that presses the valve body 70 inward in the radial direction. Specifically, when the spring 72 has a contracted shape, the force that presses the valve body 70 inward in the radial direction is higher than when the spring 72 has a contracted shape.

  On the other hand, as described above, when the oil discharged from the oil pump 31 is supplied to the oil passage 61, the valve body 70 is pressed outward in the radial direction by the oil pressure of the oil passage 61 and the elastic force of the spring 71. Load to occur. When the spring 72 is contracted due to the relatively low temperature of the hub 29, the valve body 70 moves outward in the radial direction by this load. As a result, the port 74 is opened. That is, the oil passage 61 and the oil passage 66 are connected via the port 74. Accordingly, the oil in the oil passage 61 is sent to the lubricated portion 64 via the oil passage 66 and the oil passage 62 in the same manner as in the first specific example. That is, the same effect as the first specific example can be obtained also in the second specific example.

  On the other hand, when the temperature of the rotor 32 becomes relatively high and the heat is transmitted to the annular member 73 via the plate 56 and the hub 29 and the spring 72 is extended, the valve body 70 is moved radially inward. The load to be pressed toward increases. For this reason, even if a load that presses the valve body 70 outward in the radial direction due to the oil pressure of the oil passage 61 and the elastic force of the spring 71 occurs, the port 74 is blocked by the valve body 70. That is, the oil passage 61 and the oil passage 6 are blocked. Accordingly, the oil in the oil passage 61 is not supplied to the oil passage 66. Thus, when the heat of the rotor 32 is relatively high, the oil in the oil passage 61 can be prevented from flowing into the oil passage 66. Therefore, “the heat of the rotor 32 is transmitted to the oil in the oil passage 66 and the temperature rises and the oil is supplied to the lubricated portion 64” can be avoided. Thus, the switching mechanism 68 has a function as “a flow control valve that controls the amount of oil supplied from the oil passage 61 to the oil passage 66 based on the temperature of the rotor 32”.

  The second specific example corresponds to the inventions of claims 1, 2, 3, and 4, and the correspondence between the configuration of the second specific example and the configuration of the present invention. The switching mechanism 68 corresponds to the switching mechanism of the present invention, the valve body 70 corresponds to the valve body of the present invention, and the spring 72 corresponds to the temperature-sensitive deformation member of the present invention. The correspondence between the other configurations in the second specific example and the configuration of the present invention is the same as the corresponding relationship between the first specific example and the configuration of the present invention. In the second specific example, the temperature at which the port 74 opened / closed by the operation of the valve body 70 is opened / closed is determined by conditions such as the spring constant of the spring 71 and the temperature at which the spring 72 is deformed. These conditions are design items that can be arbitrarily changed.

(Third example)
Next, a “third specific example” of the cooling mechanism of the present invention will be described with reference to FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. In the third specific example, a switching mechanism 79 is provided between the oil passage 61 and the oil passage 66. The switching mechanism 79 has a function of cutting off the connection between the oil passage 61 and the oil passage 66 and a function of connecting the oil passage 66 and the oil passage 61. The configuration of the switching mechanism 79 will be specifically described. First, an annular member 80 is fixed to the outer periphery of the rotary shaft 28 in place of the flange 50. The annular member 80 is constituted by a member different from the metal material constituting the rotating shaft 28, and the annular member 80 and the rotating shaft 28 are integrally rotated. The annular member 80 is provided with a cylinder chamber 81. The cylinder 81 is provided at one place in the circumferential direction of the annular member 80. The cylinder chamber 81 has a radial depth centered on the axis B1. A valve body 82 is disposed in the cylinder chamber 81. The valve body 82 has a configuration capable of operating in the depth direction of the cylinder chamber 81, specifically, a disc shape or a columnar shape. The annular member 80 is provided with an oil passage 83 that connects the cylinder chamber 81 and the oil passage 61. The annular member 80 is provided with a port 84. The port 84 passes through the annular member 80 in the direction along the axis B1. The port 84 connects the cylinder chamber 81 and one end of the oil passage 66. For this reason, the port 84 is blocked or opened by the operation of the valve element 82.

  On the other hand, an oil passage 85 is formed in the annular member 80. Further, an oil passage 86 is provided in the rotary shaft 28, and the oil passage 86 and the oil passage 85 are connected to each other. An oil passage 87 branched from the oil passage 77 is provided, and the oil passage 87 is connected to the oil passage 86. A part of the oil passage 87 is provided in the casing 4. The annular member 80 is provided with a throttle portion 88 that connects the oil passage 85 and the cylinder chamber 81. The throttle portion 88 is an oil passage through which oil flows, and the cross-sectional area in a plane orthogonal to the oil flow direction is configured to be narrower than the pressure receiving area where the hydraulic pressure of the cylinder chamber 81 acts on the valve body 81. The cross-sectional area of the oil passage 85 in a plane orthogonal to the oil flow direction is configured to be wider than the cross-sectional area of the throttle portion 88. The throttle portion 88 may be either an orifice or a choke. A switching mechanism 79 is configured by the annular member 80, the cylinder chamber 81, the oil passages 83 and 85, the throttle portion 88, and the oil passage 87 configured as described above.

  The operational effects of the third specific example 3 will be described. When the brake pedal 75 is not depressed, the hydraulic pressure in the hydraulic chamber 34 is relatively low. The same hydraulic pressure as the hydraulic pressure in the hydraulic chamber 34 acts on the pressure receiving surface of the valve body 82 via the oil passages 87 and 85 and the throttle portion 88. The oil pressure acting on the pressure receiving surface of the valve body 82 generates a force that presses the valve body 82 inward in the radial direction of the rotary shaft 28. On the other hand, the oil pump 31 is driven as described above, and the oil discharged from the oil pump 31 is supplied to the oil passage 61. Then, the oil pressure of the oil passage 61 acts on the valve body 82, and a force that presses the valve body 82 outward in the radial direction of the rotary shaft 28 acts. Here, when the brake pedal 75 is not depressed, the hydraulic pressure acting on the valve body 82 via the throttle portion 88 is relatively low. For this reason, the valve body 82 moves outward in the radial direction of the rotary shaft 28, and the port 84 is opened. Then, the oil in the oil passage 61 is supplied to the oil passage 66 via the oil passage 83 and the port 84. When the brake pedal 75 is not depressed, the hydraulic pressure in the hydraulic chamber 34 is relatively low, and the brake pads 35 and 36 are not pressed against the rotor 32. Therefore, the temperature of the rotor 32 does not rise. Therefore, the heat supplied to the oil passage 66 is dissipated in the air via the rotor 32, and the oil is cooled. The cooled oil is sent to the lubricated portion 64 via the oil passage 62.

  On the other hand, when the brake pedal 75 is depressed, the hydraulic pressure in the hydraulic chamber 34 increases and the brake pads 35 and 36 are pressed against the rotor 32. For this reason, the temperature of the rotor 32 rises due to frictional heat. Further, when the brake pedal 75 is depressed and the hydraulic pressure in the hydraulic chamber 34 increases, the hydraulic pressure is transmitted to the cylinder chamber 81 through the oil passage 87 oil pump via the input shaft oil passage 85. For this reason, the force which presses the valve body 82 inward in the radial direction of the rotating shaft 28 increases, and the valve body 82 operates in the same direction. As a result, the port 84 is blocked by the valve body 82. Therefore, the oil in the oil passage 61 is not supplied to the oil passage 66. In other words, when the temperature of the rotor 32 is relatively high, the oil in the oil passage 61 is not supplied to the oil passage 66. Therefore, “the heat of the rotor 32 is transmitted to the oil in the oil passage 66 and the temperature rises. "Is sent to the lubricated part 64". Thus, the switching mechanism 79 has a function as a flow control valve that controls the amount of oil sent from the oil passage 61 to the oil passage 66 based on a temperature change.

  In the third specific example, the sectional area of the throttle portion 88 is narrower than the sectional area of the cylinder chamber 81. For this reason, when the brake pedal 75 is depressed and then the brake pedal 75 is returned, the flow resistance when the oil in the cylinder chamber 81 passes through the throttle portion 88 can be relatively increased. For this reason, when the valve body 82 operates toward the outer side of the rotating shaft 28, the hydraulic pressure acting on the valve body 82 from the cylinder chamber 81 can be relatively gradually reduced. Therefore, it is possible to relatively delay the time when the port 84 is opened until the rotor 32 whose temperature has increased is cooled. Furthermore, when the rotational speed of the wheel 1 becomes relatively high, the centrifugal force acting on the valve body 82 increases, and the force that presses the valve body 82 outward in the radial direction of the rotary shaft 28 increases. For this reason, when the rotational speed of the wheel 1 is relatively high, the time when the blocked port 84 is released is earlier than when the rotational speed of the wheel 1 is relatively low. And when the rotational speed of the wheel 1 is relatively high, the flow velocity of the air contacting the surface of the rotor 32 is relatively higher than when the rotational speed of the wheel 1 is relatively low, Since the heat dissipation efficiency becomes relatively high, in this case, the port 84 can be opened relatively early, and the oil can be sent to the oil passage 66 to be cooled.

  This third specific example corresponds to the inventions of claims 1, 2, 3, 4, 5, 6, 7, and 8. The correspondence between the configuration of the specific example 3 and the configuration of the present invention will be described. The switching mechanism 79 corresponds to the switching mechanism of the present invention, and the valve body 82 corresponds to the valve body of the present invention. The correspondence between the other configurations in the third specific example and the configuration of the present invention is the same as the corresponding relationship between the first specific example and the configuration of the present invention. In the third specific example, the timing (hydraulic pressure) when the port 84 is opened and closed is determined by conditions such as the pressure receiving area where the hydraulic pressure acts on the valve body 82 and the area of the throttle portion 88. These conditions are design items that can be arbitrarily changed.

  Further, the braking mechanism in the present invention may have a structure that converts electromagnetic force into braking force. The speed reducer 20 shown in FIG. 3 can also be constituted by a planetary roller mechanism. This planetary roller mechanism is a traction transmission device. That is, the speed reducer may be configured with either a gear transmission or a traction transmission. In this case, the planetary roller mechanism is included in the lubricated portion that is lubricated or cooled by the oil. Furthermore, in the above description, a brake pedal 75 operated by a foot is described as a braking request generating device operated by a vehicle occupant. In addition, a brake request generation device that is manually operated may be provided in the interior of the vehicle, and the hydraulic pressure of the hydraulic chamber 34 may be controlled based on the operation state of the brake request generation device. The manually operated braking request generator includes a lever that can operate around a fulcrum or a knob that rotates within a predetermined angular range. In the second specific example or the third specific example, the switching mechanism may be a flow control valve having a ball-shaped valve body or a shaft-shaped valve body.

It is typical sectional drawing which shows the motor cooling structure of this invention. It is a typical longitudinal cross-sectional view of the vehicle which has the in-wheel motor of this invention. It is a longitudinal cross-sectional view which shows the in-wheel motor of this invention. It is typical sectional drawing which shows the other example of the motor cooling structure of this invention. It is typical sectional drawing which shows the further another example of the motor cooling structure of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel, 2 ... Suspension device, 3 ... Vehicle body, 4 ... Casing, 7 ... Electric motor, 28 ... Rotating shaft, 29 ... Hub, 31 ... Oil pump, 32 ... Rotor, 33 ... Disc caliper, 34 ... Hydraulic chamber, 35, 36 ... brake pads, 56 ... plates, 64 ... lubricated parts, 61, 62, 66 ... oil passages, 68, 79 ... switching mechanisms, 70, 82 ... valve bodies, 72 ... springs.

Claims (8)

A casing attached to the vehicle body via a suspension device, an electric motor provided inside the casing, a rotating member provided to transmit power to the electric motor, and attachment to the rotating member and the rotating member A wheel that can be removed, a braking mechanism that is attached to the casing and applies a braking force to the wheel via the rotating member, and a cover that is provided in the casing and that is cooled or lubricated by oil. In a motor cooling structure having a lubricating part and a heat exchanging part that cools oil by exchanging heat between oil and air supplied to the lubricated part,
The motor cooling structure, wherein the heat exchanging portion is provided on the rotating member. An oil pump that is driven by the power of the electric motor and sucks and discharges oil is provided;
The rotating member includes a first rotating member to which power of the electric motor is transmitted, and a second rotating member attached to the outer periphery of the first rotating member and rotating integrally with the first rotating member. And
The braking mechanism includes a friction member that contacts the second rotating member and generates a braking force;
The heat exchange part is provided on the second rotating member,
2. The motor cooling structure according to claim 1, wherein an oil passage through which oil discharged from the oil pump passes and connected to the heat exchange unit is provided in the first rotating member.   The oil passage is shut off when the temperature of the rotating member is relatively high, and has a switching mechanism that opens the oil passage when the temperature of the rotating member is relatively low. The motor cooling structure according to claim 2.   A valve body that opens and closes the oil passage; and the oil passage expands when the temperature of the rotating member is relatively high, and contracts when the temperature of the rotating member is relatively low. The motor cooling structure according to claim 2, further comprising a switching mechanism having a temperature-sensitive deformation member that applies a force in a closing direction to the valve body. The braking mechanism is configured such that a braking force is controlled by hydraulic pressure,
A switching mechanism that shuts off the oil passage when the hydraulic pressure for controlling the braking force of the braking mechanism is relatively high, and opens the oil passage when the hydraulic pressure for controlling the braking force of the braking mechanism is relatively low. The motor cooling structure according to claim 2, wherein the motor cooling structure is provided. The switching mechanism includes a valve body that opens and closes the oil passage;
A cylinder chamber in which the valve body is disposed and hydraulic pressure is applied to the valve body;
6. A throttle part configured to have a narrower area in a plane perpendicular to the oil flow direction of the oil passage than a pressure receiving area where hydraulic pressure acts on the valve body in the cylinder chamber. The motor cooling structure described in 1.   2. A switching mechanism that shuts off the oil passage when the rotation speed of the rotation member is relatively high, and opens the oil passage when the rotation speed of the rotation member is relatively low. The motor cooling structure according to 2.   A switching mechanism that blocks the oil passage when centrifugal force generated by rotation of the rotating member is relatively weak, and opens the oil passage when centrifugal force generated by rotation of the rotating member is relatively strong. The motor cooling structure according to claim 2.

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