JP2015116864A - Assembly structure of in-wheel motor drive device and wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assembly structure of an in-wheel motor drive device and a wheel which performs cooling without enlargement of a unit.SOLUTION: In an in-wheel motor drive device, a unit housing 11 attached to a vehicle body is installed at an inner space portion of a wheel 70, an electric motor for generating a driving force is stored in the unit housing 11. Further, the in-wheel motor drive device has a wheel hub which transmits rotation of the electric motor to the wheel. An assembly structure of the in-wheel motor drive device and the wheel is composed of the in-wheel motor drive device and the wheel connected with the wheel hub. In the assembly structure, a ventilation duct 75 which generates air flowing to the inner side in a vehicle width direction by rotation of the wheel is provided at the inner side of the wheel 70. The structure inhibits hot air from staying at the inner side of the wheel 70 and enables effective air-cooling to be performed to the unit housing 11 installed in the wheel 70.

Description

  The present invention relates to an assembly structure of an in-wheel motor drive device having a cooling system and a wheel.

  The in-wheel motor drive device is installed in the inner space of the wheel of an automobile, and reduces the rotation of the electric motor that generates driving force inside the unit housing attached to the vehicle body and the electric motor to the wheel hub. A transmission reduction gear.

  When the in-wheel motor drive device is operated in a high load state or a high-speed rotation state, an increase in temperature inside the unit housing may cause damage to internal components as the efficiency of the electric motor decreases and the viscosity of the lubricating oil decreases.

  For this reason, the system which cools efficiently the in-wheel motor drive device heated during driving | running | working is needed.

  Conventionally, the unit housing is cooled by air cooling. However, since the airflow is disturbed in the wheel house of the vehicle body, the unit housing of the in-wheel motor drive device is efficiently cooled only by air cooling. It ’s difficult. In addition, the cooling method in which the refrigerant is passed through the unit housing has a problem that the unit housing becomes large.

  Conventionally, Patent Document 1 discloses a technique for effectively cooling a unit housing by providing an air intake port in the unit housing and introducing traveling air into the unit housing from the air intake port.

JP 2008-213777 A

  However, in the cooling system of Patent Document 1 in which the air intake is provided in the unit housing, the air intake is attached as a separate member to the outer peripheral surface of the unit housing, so that the number of parts, the unsprung weight, and the size of the unit are increased. There is a disadvantage that invites.

  Therefore, an object of the present invention is to provide an assembly structure of an in-wheel motor drive device and a wheel that can perform effective cooling without causing an increase in size of the unit.

  In order to solve the above-described problems, the present invention is configured such that a unit housing attached to a vehicle body is installed in an inner space portion of a wheel, and an electric motor for generating a driving force is accommodated inside the unit housing. In an in-wheel motor drive device having a wheel hub that transmits the rotation of the wheel to the wheel, and an in-wheel motor drive device and a wheel that are connected to the wheel hub. Is provided with a blowing duct for generating a wind toward the inner side in the vehicle width direction.

  Of the inlet and outlet provided in the air duct, if the outlet is smaller than the inlet, the flow rate of the exhaust can be increased by the venturi effect and negative pressure can be generated. An entrainment airflow can be generated effectively.

  It is desirable to provide a fin that forms an airflow toward the inlet of the air duct inside the wheel.

  An airfoil inclined portion that generates a circular airflow may be formed on the inner peripheral surface of the wheel.

  The air blowing duct can be formed by a groove provided along the inner surface of the spoke portion that protrudes radially from the outer periphery of the hub portion of the wheel, and a cover portion that is detachably fitted in the groove portion.

  The cover portion can be formed of a hard synthetic resin.

  As described above, according to the present invention, the air duct is provided on the inner side of the wheel on which the in-wheel motor drive device is installed so as to generate the wind toward the inner side in the vehicle width direction by the rotation of the wheel. Hot air does not flow inside, and the unit housing installed in the wheel can be effectively air-cooled.

It is a schematic plan view of the electric vehicle which has an in-wheel motor drive device. It is the schematic which shows the state which installed the in-wheel motor drive device in the wheel house. FIG. 3 is a partially enlarged view of FIG. 2. It is the perspective view which looked at one Embodiment of the wheel used for the in-wheel motor drive device concerning this invention from the inner surface side. It is an enlarged view of the part enclosed with the dashed-two dotted line of FIG. It is a perspective view which shows the state which removed the cover part of one duct for ventilation among the ducts for ventilation provided in the wheel of FIG. It is the perspective view which looked at other embodiment of the wheel used for the in-wheel motor drive device concerning this invention from the inner surface side. FIG. 8 is an enlarged view of a portion surrounded by a two-dot chain line in FIG. 7. It is a perspective view which shows the state which removed the cover part of one ventilation duct among the ducts for ventilation provided in the wheel of FIG. It is a longitudinal cross-sectional view which shows embodiment of an in-wheel motor drive device. It is the figure which looked at the rotary pump of FIG. 10 from the axial direction. It is an enlarged view of the reduction gear of the in-wheel motor drive device of FIG. It is sectional drawing along the XIII-XIII line of FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, an electric vehicle 1 including an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 2, front wheels 3 as steering wheels, drive wheels 4 (rear wheels), left and right The in-wheel motor drive device A which transmits a driving force to each of the drive wheels 4 is provided. As shown in FIG. 2, the drive wheels 4 are accommodated inside a wheel house 2 a of the chassis 2 and supported by the chassis 2 via a suspension device (suspension) 5. As a mounting form of the in-wheel motor drive device A, any of the front wheel drive system and the four wheel drive system may be used in addition to the rear wheel drive system shown in FIG.

  The suspension device 5 supports the driving wheel 4 by a suspension arm 5a extending from side to side, and absorbs vibration received from the ground by the driving wheel 4 from the ground by a strut 5b including a coil spring and a shock absorber. Transmission is suppressed. The suspension device 5 is an independent suspension type in which the left and right wheels can be moved up and down independently in order to improve the followability to road surface irregularities and efficiently transmit the driving force of the drive wheels 4 to the road surface. desirable.

  The electric vehicle 1 needs to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 2 by housing the in-wheel motor drive device A that drives the left and right drive wheels 4 in the wheel house 2a. Therefore, it is possible to secure a wide cabin space and control the rotation of the left and right drive wheels.

  As shown in FIG. 10, the in-wheel motor driving device A includes an electric motor 10 that generates a driving force, a speed reducer 20 that decelerates and outputs the rotation of the electric motor 10, and an output from the speed reducer 20 as driving wheels. 4 (see FIG. 2).

  The electric motor 10 and the speed reducer 20 are accommodated in the unit housing 11. The unit housing 11 includes a housing 11a on the electric motor 10 side and a housing 11b on the speed reducer 20 side. The housing 11a and the housing 11b are connected in the axial direction by bolts 21.

  The drive wheel 4 includes a wheel 70 and a tire 71 as shown in FIG.

  The wheel 70 includes a hub portion 72 that is attached to the flange portion 35 of the wheel hub bearing portion 30 by bolts 36, and a plurality of spoke portions 73 that project radially from the outer periphery of the hub portion 72 toward the outer diameter direction. And an annular rim portion 74 provided on the outer end surface of the spoke portion 73, and a tire 71 is mounted on the outer peripheral surface of the rim portion 74.

  As shown in FIGS. 4 to 6, a blower duct 75 extending from the hub portion 72 toward the rim portion 74 is provided on the inner surface side of the spoke portion 73 of the wheel 70.

  As shown in FIG. 6, the air duct 75 is formed by a groove portion 76 provided along the inner surface of the spoke portion 73 and a cover portion 77 that is detachably fitted in the groove portion 76. Are provided with a suction port 78 and a discharge port 79 on the rim 74 side.

  The cover portion 77 is formed of a hard synthetic resin and is fitted into the groove portion 76.

  As shown in FIGS. 2 and 3, the suction port 78 and the discharge port 79 of the air duct 75 are formed so that the discharge port 79 is narrower and smaller than the suction port 78. Thus, if the discharge port 79 is formed to be narrower and smaller than the suction port 78, the flow velocity of exhaust can be increased by the venturi effect and negative pressure can be generated, so that an entrained airflow of ambient air is effectively generated. be able to. 2 and 3, the flow of the airflow is indicated by thin arrows.

  As described above, when the air duct 75 is provided along the inner surface of the spoke part 73 of the wheel 70, air is discharged from the suction port 78 on the hub part 72 side of the air duct 75 to the rim part 74 side by rotation of the wheel. Since air flows toward the outlet 79 and wind toward the inner side in the vehicle width direction is generated, hot air does not flow inside the wheel 70, and the unit housing 11 of the in-wheel motor driving device A installed in the wheel 70. Is effectively air-cooled.

  In the embodiment shown in FIGS. 7 to 9, the fin 80 is provided on the outer peripheral surface of the hub portion 72 of the wheel 70, and the air flow toward the suction port 78 of the air duct 75 is created by the fin 80 to enhance the air cooling effect. Is shown.

  Further, an airfoil inclined portion may be formed on the inner peripheral surface of the rim portion 74 of the wheel 70 to enhance the air cooling effect by a circular airflow.

  As shown in FIG. 2, a brake rotor 82 is mounted between the hub portion 72 of the wheel 70 and the flange portion 35 of the wheel hub bearing portion 30, and the brake caliper 83 of the brake rotor 82 is installed in the wheel 70. doing. In this invention, since the airflow in the wheel 70 is good, the cooling of the brake device is also effective.

  As shown in FIG. 10, for example, a radial gap type electric motor 10 is used in which a stator 12 is provided on the inner peripheral surface of a housing 11 a and a rotor 13 is provided at an interval on the inner periphery of the stator 12. ing.

  The rotor 13 has a motor shaft 14 in the center. The motor shaft 14 is connected to the input shaft 22 of the speed reducer 20 and is inserted into the housing 11b of the speed reducer 20, and is rotated with respect to the housing 11a by the bearing 15. It is supported freely.

  The housing 11b of the speed reducer 20 is provided with an oil tank 41 for lubricating oil at the lower portion, the lubricating oil in the oil tank 41 is sucked by the oil pump 61, and the lubricating oil is supplied to the electric motor 10 and the speed reducer 20 for lubrication. And cooling.

  The lubricating oil includes an oil supply passage 43 extending rearward along the inside of the housing 11a from the discharge port 66 of the oil pump 61 driven by the rotation of the electric motor 10, and an internal passage 44 from the rear end portion of the motor shaft 14, It is supplied to the inside of the speed reducer 20 through the internal passage 45 of the input shaft 22 of the speed reducer 20.

  The lubricating oil return passage 48 includes a discharge port 49 provided at the bottom of the housing 11 b of the speed reducer 20 and a passage that reaches the suction port of the oil pump 61 through the oil tank 41.

  Here, as shown in FIG. 11, the oil pump 61 rotates using the output rotation of the speed reducer 20 driven by the motor shaft 14 of the electric motor 10, and with the rotation of the inner rotor 62. Thus, the cycloid pump includes an outer rotor 63 that rotates in a driven manner, a pump chamber 64, a suction port 65 that communicates with the return passage 48, and a discharge port 66 that communicates with the oil supply passage 43.

  Inner rotor 62 has a tooth profile formed of a cycloid curve on the outer diameter surface. Specifically, the shape of the tooth tip portion 62a is an epicycloid curve, and the shape of the tooth gap portion 62b is a hypocycloid curve. The inner rotor 62 rotates integrally with the output shaft 26 (see FIG. 10).

  The outer rotor 63 has a tooth profile formed of a cycloid curve on the inner diameter surface. Specifically, the shape of the tooth tip portion 63a is a hypocycloid curve, and the shape of the tooth gap portion 63b is an epicycloid curve. The outer rotor 63 is rotatably supported by the pump case 67.

  The inner rotor 62 rotates about the rotation center c1. On the other hand, the outer rotor 63 rotates around a rotation center c2 different from the rotation center c1 of the inner rotor. Further, when the number of teeth of the inner rotor 62 is n, the number of teeth of the outer rotor 63 is (n + 1). In this embodiment, n = 5.

  A plurality of pump chambers 64 are provided in the space between the inner rotor 62 and the outer rotor 63. When the inner rotor 62 rotates using the rotation of the motor shaft 14, the outer rotor 63 rotates in a driven manner. At this time, since the inner rotor 62 and the outer rotor 63 rotate about different rotation centers c1 and c2, the volume of the pump chamber 64 continuously changes. As a result, the lubricating oil flowing in from the suction port 65 is pumped from the discharge port 66 to the oil supply passage 43.

  As shown in FIGS. 12 and 13, the speed reducer 20 employs a cycloid type. The speed reducer 20 rotatably supports two curved plates 24 by eccentric shaft portions 23 provided at two locations of the input shaft 22, and a corrugated tooth profile 24 a formed on the outer periphery of the curved plate 24 is reduced. 20 is engaged with an outer pin 25 disposed inside the housing 11 b, and the curved plate 24 is eccentrically oscillated by the rotation of the input shaft 22, and the rotation of the curved plate 24 is arranged coaxially with the input shaft 22. The wheel hub 31 is rotated by the output from the output shaft 26 (see FIG. 10).

  The number of outer pins 25 disposed inside the housing 11 b of the speed reducer 20 is greater than the corrugated tooth profile 24 a on the outer periphery of the curved plate 24.

  The outer pin 25 is provided in an outer pin housing 50 that is supported in a floating state on the inner diameter surface of the housing 11b of the speed reducer 20 via a gap.

  One end of the input shaft 22 is connected to the motor shaft 14 of the electric motor 10 by spline fitting and is driven to rotate by the electric motor 10 (see FIG. 10). An eccentric shaft portion 23 is provided.

  A pair of two eccentric shaft portions 23 are provided in the axial direction of the input shaft 22. The pair of eccentric shaft portions 23 is provided such that the center of the cylindrical outer diameter surface is 180 degrees out of phase in the circumferential direction, and a rolling bearing 28 is fitted to each outer diameter surface of the pair of eccentric shaft portions 23. Are combined.

  The input shaft 22 provided with the pair of eccentric shaft portions 23 is provided with a pair of counterweights 55 with a 180 ° phase shift in the circumferential direction so as to sandwich the pair of eccentric shaft portions 23.

  The curved plate 24 is rotatably supported by the input shaft 22 by a rolling bearing 28, and a corrugated tooth profile 24a formed on the outer periphery thereof is a trochoidal curved tooth profile. As shown in FIG. 13, in the curved plate 24, a plurality of pin holes 24b are formed at equal intervals on one circle centered on the rotation axis, and each of the pair of pin holes 24b aligned in the axial direction is formed inside the curved plate 24. The pin 29 is inserted with a margin, and a part of the outer periphery of the needle roller bearing 29a rotatably supported by the inner pin 29 is in contact with a part of the inner periphery of the pin hole 24b.

  As shown in FIG. 12, the speed reducer 20 engages with a pair of curved plates 24 as a revolving member that is rotatably held by a pair of eccentric shaft portions 23, and a corrugated tooth profile 24 a on the outer peripheral portion of the curved plate 24. A plurality of outer pins 25, an output shaft 26 that outputs the rotation of the curved plate 24, and a center between the pair of curved plates 24 and abutting against the end surfaces of the curved plates 24 to prevent the curved plate from tilting. A collar 24c.

  The output shaft 26 has a flange portion 26a and a shaft portion 26b. Inner pins 29 are fixed to the flange portion 26 a at equal intervals on a circumference centered on the rotation axis O of the output shaft 26. A wheel hub 31 is fixed to the outer diameter surface of the shaft portion 26b (see FIG. 10).

  As shown in FIG. 13, the outer pins 25 are provided at equal intervals on the circumferential track of the rotation axis O of the input shaft 22. When the curved plate 24 revolves, the outer peripheral corrugated tooth profile 24a and the outer pin 25 engage with each other to cause the curved plate 24 to rotate.

  The outer pin 25 disposed in the housing 11b is not directly held by the housing 11b, but is held by an outer pin housing 50 supported in a floating state with respect to the inner wall of the housing 11b as shown in FIG. Has been. More specifically, both ends of the outer pin 25 in the axial direction are rotatably supported by the needle roller bearing 51 with respect to the outer pin housing 50. Thus, by making the outer pin 25 rotatable with respect to the outer pin housing 50, the contact resistance due to the engagement with the curved plate 24 can be reduced.

  The outer pin housing 50 includes a cylindrical portion 50a and a pair of ring portions 50b extending radially inward from both axial end portions of the cylindrical portion 50a.

  The output shaft 26 is rotatably supported via a bearing 52 on the inner periphery of the pair of ring portions 50 b of the outer pin housing 50. The inner diameter surface of the flange portion 26 a of the output shaft 26 and the outer diameter surface of the input shaft 22 are supported through a bearing 53 so as to be relatively rotatable.

  The curved plate 24 is incorporated between the opposing flange portions 26 a of the output shaft 26. Further, both ends of the inner pin 29 penetrating the pin hole 24b of the incorporated curved plate 24 are supported by the flange portion 26a facing the output shaft 26.

  The plurality of inner pins 29 supported by the flange portions 26a opposed to the output shaft 26 are provided at equal intervals on a circumferential track centering on the rotation axis O of the input shaft 22, and have a frictional resistance with the curved plate 24. In order to reduce this, a needle roller bearing 29a is provided at a position where it abuts against the inner wall surface of the pin hole 24b of the curved plate 24. The inner diameter dimension of the pin hole 24b is set to be larger by a predetermined amount than the outer diameter dimension of the inner pin 29 (referred to as “maximum outer diameter including the needle roller bearing 29a”; the same applies hereinafter).

  A pair of ring portions 50b extending radially inward of the outer pin housing 50 are provided with a plurality of outer pin holding holes 50c penetrating in the thickness direction. The outer pin holding holes 50 c each extend in a direction parallel to the rotation axis O of the input shaft 22 and hold the outer ring 51 a of the needle roller bearing 51. Further, the corresponding outer pin holding holes 50c of the pair of ring portions 50b are provided at the same position in the circumferential direction and face each other. That is, the center axis of the pair of outer pin holding holes 50c coincides, and when the outer pin housing 50 is attached to the housing 11b, the center axis of the outer pin holding hole 50c becomes parallel to the rotation axis O of the input shaft 22. .

  Thereby, the outer pin 25 can be held in parallel with the rotation axis O of the input shaft 22. Since the outer pin holding holes 50c can be simultaneously formed by simultaneous processing, the central axes of the opposed outer pin holding holes 50c can be relatively easily matched.

  Further, from the viewpoint of reducing the weight of the in-wheel motor drive device A, the housings 11a and 11b are formed of a light metal such as an aluminum alloy or a magnesium alloy. On the other hand, it is desirable to form the outer pin housing 50, which requires high strength, from carbon steel.

  As shown in FIG. 12, an outer pin thrust plate 50d is fixed to the side surface of the ring portion 50b of the outer pin housing 50 in order to prevent the outer pin 25 from coming off in the axial direction.

  As shown in FIG. 10, the wheel hub bearing portion 30 includes an inner ring member 32 fixedly connected to the outer diameter surface of the shaft portion 26b of the output shaft 26, and an outer ring that rotatably holds the inner ring member 32 with respect to the housing 11b. A member 33. The inner ring member 32 and the outer ring member 33 constitute a double-row angular ball bearing, and a double-row rolling element 34 is installed between the inner ring member 32 and the outer ring member 33. The inner ring member 32 is integrally provided with a flange portion 35, and the drive wheel 4 is fixedly connected to the flange portion 35 by a bolt 36 (see FIG. 2).

  In the description of the operation in the above-described embodiment, electric power is supplied to the electric motor 10 to drive the electric motor 10 and the power from the electric motor 10 is transmitted to the drive wheels. When the vehicle decelerates or goes down a hill, the power from the drive wheel side is converted into high-rotation and low-torque rotation by the speed reducer 20 and transmitted to the electric motor 10. good. Furthermore, the electric power generated here may be stored in a battery and used later to drive the electric motor 10 or to operate other electric devices provided in the vehicle.

  In the above-described embodiment, the radial gap motor includes the stator 12 fixed to the housing 11a of the electric motor 10 and the rotor 13 disposed at a position facing the inner side of the stator 12 with a radial gap. Although the example which employ | adopted was shown, the motor of arbitrary structures is applicable not only to this but. For example, an axial gap motor in which the stator and the rotor are arranged to face each other via a gap opened in the axial direction may be used.

  Furthermore, in the in-wheel motor drive device A according to the present invention, an example in which a cycloid type speed reducer is adopted has been shown. However, the present invention is not limited to this, and a planetary speed reducer, a two-axis parallel speed reducer, and other speed reducers It may be applicable and may be a so-called direct motor type that does not employ a reduction gear. In this specification, “electric vehicle” is a concept that includes all vehicles that obtain driving force from electric power, and includes, for example, a hybrid car that uses an in-wheel motor drive device A and an internal combustion engine in combination. It should be understood as a thing.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Chassis 2a Wheel house 3 Front wheel 4 Drive wheel 5 Suspension device 5a Suspension arm 5b Strut 10 Electric motor 11 Unit housing 11a Housing 11b Housing 12 Stator 13 Rotor 14 Motor shaft 15 Bearing 20 Reduction gear 21 Bolt 22 Input shaft 23 Eccentricity Shaft portion 24 Curved plate 24a Corrugated tooth profile 24b Pin hole 24c Center collar 25 Outer pin 26 Output shaft 26a Flange portion 26b Shaft portion 28 Rolling bearing 29 Inner pin 29a Bearing 30 Wheel hub bearing portion 31 Wheel hub 32 Inner ring member 33 Outer ring member 34 Roll Moving body 35 Flange portion 36 Bolt 41 Oil tank 43 Oil supply passage 44 Internal passage 45 Internal passage 48 Return passage 49 Discharge port 50 Outer pin housing 50a Cylindrical portion 50b Ring portion 50c Outer pin holding hole 50d Outer pin thrust Top plate 51 Bearing 51a Outer ring 52 Bearing 53 Bearing 55 Counterweight 61 Oil pump 62 Inner rotor 62a Tooth tip portion 62b Tooth groove portion 63 Outer rotor 63a Tooth tip portion 63b Tooth groove portion 64 Pump chamber 65 Suction port 66 Discharge port 67 Pump case 70 Wheel 71 Tire 72 Hub portion 73 Spoke portion 74 Rim portion 75 Air duct 76 Groove portion 77 Cover portion 78 Suction port 79 Discharge port 80 Fin 82 Brake rotor 83 Brake caliper A In-wheel motor drive device O Rotating axis c1 Rotation center c2 Rotation center

Claims (7)

  An in-wheel having a wheel hub in which a unit housing attached to a vehicle body is installed in an inner space of the wheel, an electric motor for generating a driving force is housed in the unit housing, and the rotation of the electric motor is transmitted to the wheel In an assembly structure of an in-wheel motor drive device and a wheel composed of a motor drive device and a wheel connected to a wheel hub, for blowing air that generates wind toward the inside in the vehicle width direction by rotation of the wheel inside the wheel An assembly structure of an in-wheel motor drive device and a wheel, wherein a duct is provided.   2. The assembly structure of an in-wheel motor drive device and a wheel according to claim 1, wherein a discharge port is smaller than a suction port among a suction port and a discharge port provided in the air duct.   The assembly structure of an in-wheel motor drive device and a wheel according to claim 2, wherein a fin for forming an air flow toward the suction port of the air duct is provided inside the wheel.   The assembly of the in-wheel motor drive device and the wheel according to any one of claims 1 to 3, wherein an airfoil inclined portion for generating a circular airflow is formed on an inner peripheral surface of the wheel. Construction.   The said air duct is comprised from the groove part provided along the inner surface of the spoke part which protrudes radially from the outer periphery of the hub part of a wheel, and the cover part fitted to this groove part so that attachment or detachment is possible. An assembly structure of the in-wheel motor drive device and the wheel according to any one of the items.   The assembly structure of an in-wheel motor drive device and a wheel according to claim 1, wherein the cover portion is made of a hard synthetic resin.   The wheel according to any one of claims 1 to 6.

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