JP2017003047A - In-wheel motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the damage of a parallel-axis gear reduction gear caused by insufficient lubrication even at a restart of an electric motor.SOLUTION: An in-wheel motor drive unit 21 comprises a motor part A, a reduction gear part B constituted of a parallel-axis gear reduction gear 39 which is composed of a plurality of gears 30 to 33, and a wheel bearing part C. The in-wheel motor drive unit lubricates the gear 30 to 33 by a splash by the rotation of the gears 30 to 33 of the parallel-axis gear reduction gear 39 in a non-pump oil bath state. The parallel-axis gear reduction gear 39 comprises the first gear 30 which is coaxially connected to a shaft end of a motor rotating shaft 25 of the motor part A, and an oil sump 56 which stores a lubricant by the splash by the rotation of a plurality of the gears 30 to 33, and after that, drips the lubricant to the first gear 30 is arranged above the first gear 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-wheel motor drive device in which, for example, an output shaft of an electric motor and a wheel bearing are connected via a reduction gear.

  A conventional in-wheel motor drive device has a structure disclosed in Patent Document 1, for example. The in-wheel motor drive device disclosed in Patent Document 1 includes an electric motor that generates a driving force, a parallel shaft gear reducer that decelerates and outputs the rotation of the electric motor, and outputs from the parallel shaft gear reducer. It consists of a wheel hub that transmits to.

  This in-wheel motor drive device is provided with an intermediate plate between the electric motor and the parallel shaft gear reducer, a motor housing for accommodating the electric motor is provided on the inboard side of the intermediate plate, and an outboard of the intermediate plate The structure which provided the gear housing which accommodates a parallel shaft gear reducer in the side is comprised.

  The electric motor includes a stator fixed to a motor housing and a rotor shaft that is rotatably supported inside the stator. The parallel shaft gear reducer includes a motor input gear coaxially connected to the rotor shaft of the electric motor, a first counter gear rotatably supported by the gear housing and meshed with the motor input gear, and a first counter The second counter gear is supported coaxially with the gear, and the output gear is provided on the wheel hub axle and meshes with the second counter gear.

  In this in-wheel motor drive device, it is necessary to supply lubricating oil to the electric motor and the parallel shaft gear reducer for the purpose of cooling the electric motor and cooling and lubricating the parallel shaft gear reducer. As a lubrication structure for this electric motor and parallel shaft gear reducer, there is a circulation structure that incorporates a rotary pump, supplies lubricating oil discharged from the rotary pump to the electric motor and parallel shaft gear reducer, and returns it to the rotary pump. Is possible.

  However, when the rotary pump is built in, it is difficult to make the in-wheel motor drive device compact. Therefore, lubrication without the rotary pump is effective in reducing the size of the in-wheel motor drive device. In particular, in lubrication without a rotary pump in a parallel shaft gear reducer, the lubricating oil is stored in the gear housing, and the parallel shaft gear reducer is cooled and lubricated by splashing by gear rotation in an oil bath state without a pump. There is a structure to do.

  In the lubrication structure in the parallel shaft gear reducer, when the electric motor is stopped, the first counter gear and the second counter gear are partly immersed in the lubricating oil at the lower part in the gear housing, and the electric motor is driven. The gears are cooled and lubricated by splashing by rotation of the motor input gear, the first counter gear, the second counter gear, and the output gear in the oil bath state.

JP 2014-46742 A

  By the way, in the in-wheel motor drive device disclosed in Patent Document 1, when a structure that cools and lubricates the gear by splashing by rotation of the gear in an oil bath state without a pump is used, during traveling of the vehicle, etc. In a state where the parallel shaft gear reducer is driven, a sufficient lubrication state can be ensured for each gear.

  However, there is a concern that the parallel shaft gear reducer may be damaged due to insufficient lubrication, such as when the electric motor is restarted after a period of time after the vehicle stops. That is, the motor input gear constituting the parallel shaft gear reducer is disposed at a position away from the oil level of the lubricating oil stored in the lower part of the gear housing. For this reason, it becomes difficult to cool and lubricate the motor input gear by splashing by the rotation of the gear when the motor is restarted.

  On the other hand, from the viewpoint of downsizing the in-wheel motor drive device, when a small motor with low torque and high speed rotation is adopted as the electric motor, the motor input gear connected to the rotor shaft of the electric motor also rotates at high speed. As described above, when the motor input gear rotating at high speed is difficult to lubricate by splashing when the motor is restarted, the motor input gear may be damaged such as seizure.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to prevent damage to the parallel shaft gear reducer due to insufficient lubrication even when the electric motor is restarted. An in-wheel motor drive device is provided.

  As a technical means for achieving the above-mentioned object, the present invention comprises a motor unit, a speed reducer unit composed of a parallel shaft gear reducer composed of a plurality of gears, and a wheel bearing unit, and has no pump. The in-wheel motor drive device lubricates each gear by splashing by the rotation of the gear of the parallel shaft gear reducer in the oil bath state, and the parallel shaft gear reducer is attached to the shaft end of the motor rotation shaft of the motor unit. Provided with an input gear connected coaxially, and an oil reservoir for dripping the lubricating oil onto the input gear after the lubricating oil was stored by splashing by the rotation of a plurality of gears was disposed above the input gear It is characterized by.

  In the in-wheel motor drive device of the present invention, the oil reservoir portion for dropping the lubricating oil onto the input gear is disposed above the input gear, so that the motor portion is splashed by the rotation of a plurality of gears including the input gear when driving the motor portion. Thus, the lubricating oil scattered is stored in the oil reservoir. On the other hand, when restarting after stopping the motor unit, even if it is difficult to lubricate the input gear by splashing due to the rotation of multiple gears, the lubricating oil stored in the oil reservoir is dripped onto the input gear. Thus, lubrication of the input gear can be assisted with the lubricating oil dripping from the oil reservoir.

  The oil reservoir in the present invention preferably has a structure in which a dripping port that opens toward the input gear is provided at the bottom. By adopting such a structure, the lubricating oil stored in the oil reservoir can be reliably dropped from the dropping port onto the input gear when the motor unit is restarted after being stopped.

  The oil reservoir in the present invention preferably has a structure in which an electromagnetic valve for controlling the dropping of the lubricating oil to the input gear by opening and closing the dropping port is provided at the bottom. If such a structure is adopted, the lubricating oil is stored in the oil reservoir by splashing by the rotation of a plurality of gears in the closed state of the electromagnetic valve. Then, when necessary, the electromagnetic valve is opened and the lubricating oil stored in the oil reservoir is dropped onto the input gear, whereby the input gear can be lubricated with the lubricating oil dripping from the oil reservoir. Thus, employing an electromagnetic valve capable of opening and closing control is effective when the motor unit is restarted after a long period of time has elapsed since the motor unit was stopped.

  According to the present invention, even when it is difficult to lubricate the input gear by splashing by the rotation of a plurality of gears at the time of restart after the motor unit is stopped, the lubricating oil stored in the oil reservoir is input to the input gear. The input gear is easily lubricated with the lubricating oil dripping from the oil reservoir, and sufficient lubrication can be ensured in the parallel shaft gear reducer. As a result, the cooling performance and lubrication performance of the reduction gear unit can be improved, and a reliable and long-life in-wheel motor drive device can be provided.

In embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is the schematic which looked at only the gearwheel which comprises the parallel shaft gear reducer of FIG. 1 from the outboard side. It is sectional drawing which follows the PP line | wire of FIG. It is an enlarged view which shows the oil sump part of FIG. It is a figure which shows the modification of an oil sump part. It is the figure which made the electromagnetic valve of FIG. 5 the open state. 6 is a flowchart for opening / closing control of the electromagnetic valve of FIG. 5. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. FIG. 9 is a rear sectional view showing the electric vehicle of FIG. 8.

  An embodiment of an in-wheel motor drive device according to the present invention will be described in detail with reference to the drawings.

  FIG. 8 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 9 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 8, the electric vehicle 11 includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, and an in-wheel motor drive device 21 that transmits driving force to the rear wheel 14. Equip. As shown in FIG. 9, the rear wheel 14 is accommodated in a wheel housing 15 of the chassis 12 and fixed to the lower portion of the chassis 12 via a suspension device (suspension) 16.

  The suspension device 16 supports the rear wheel 14 by a suspension arm that extends to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the ground by a strut including a coil spring and a shock absorber. A stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 16 is an independent suspension type in which the left and right wheels are independently moved up and down in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the rear wheel 14 to the road surface.

  In the electric vehicle 11, the in-wheel motor drive device 21 that drives the left and right rear wheels 14 is provided inside the wheel housing 15, thereby eliminating the need to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12. Therefore, there is an advantage that a wide cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight, and further, the in-wheel motor drive device 21 is required to be downsized in order to secure a large cabin space.

  Therefore, the in-wheel motor drive device 21 of the embodiment shown in FIG. 1 has the following structure. Thereby, the compact in-wheel motor drive device 21 is implement | achieved and the electric vehicle 11 excellent in driving | running | working stability and NVH characteristic can be obtained by restraining unsprung weight.

  Before describing the characteristic configuration of this embodiment, the overall configuration of the in-wheel motor drive device 21 will be described. In the following description, with the in-wheel motor drive device 21 mounted on the vehicle, the side closer to the outside of the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing). Called.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor part A that generates a driving force, a speed reducer part B that decelerates and outputs the rotation of the motor part A, and an output from the speed reducer part B. And a wheel bearing portion C that transmits to a rear wheel 14 (see FIGS. 8 and 9) as a drive wheel. The motor part A and the speed reducer part B are accommodated in the casing 22 and attached in the wheel housing 15 (see FIG. 9) of the electric vehicle 11. The casing 22 is fastened and integrated with bolts in a separable structure including a motor housing of the motor part A and a gear housing of the speed reducer part B.

  The motor unit A is a stator 23 fixed to the casing 22, a rotor 24 disposed so as to face the inner side in the radial direction of the stator 23 with a gap, and a rotor 24 disposed on the inner side in the radial direction of the rotor 24 so as to rotate integrally with the rotor 24 A radial gap type electric motor 26 having a motor rotating shaft 25 is provided. The motor rotating shaft 25 can rotate at a high speed of about 10,000 to 1000 rotations per minute. The stator 23 is configured by winding a coil around the outer periphery of the magnetic core, and the rotor 24 has a permanent magnet or a magnetic body disposed therein.

  The motor rotating shaft 25 has a rotor 24 held by a holder portion 27 that integrally extends radially outward. The holder portion 27 has a configuration in which a concave groove into which the rotor 24 is fitted and fixed is formed in an annular shape. The motor rotating shaft 25 is rotatable with respect to the casing 22 by one end in the axial direction (right side in FIG. 1) on the rolling bearing 28 and the other end in the axial direction (left side in FIG. 1) by the rolling bearing 29. It is supported by.

  The reduction gear unit B includes a first gear 30 that is an input gear, a second gear 31 and a third gear 32 that are intermediate gears, and a fourth gear 33 that is an output gear. The first gear 30 is coaxially attached and fixed to the motor rotating shaft 25 by connecting the shaft portion 34 extending to the inboard side to the motor rotating shaft 25 by spline fitting (including serration fitting; the same applies hereinafter). Has been. The second gear 31 is attached and fixed to the intermediate shaft 35. The third gear 32 is formed integrally with the intermediate shaft 35. The fourth gear 33 is coaxially attached and fixed to the reduction gear output shaft 37 by connecting the shaft portion 36 to the inboard side shaft portion 38 of the reduction gear output shaft 37 by spline fitting.

  The reduction gear portion B decelerates the rotational movement of the motor rotating shaft 25 in two stages by meshing the first gear 30 and the second gear 31 and meshing the third gear 32 and the fourth gear 33. A parallel shaft gear reducer 39 is used.

  The shaft portion 34 of the first gear 30 is rotatably supported with respect to the casing 22 by a rolling bearing 40. The intermediate shaft 35 to which the second gear 31 is attached and fixed and the third gear 32 is integrally formed is rotatably supported by the casing 22 by rolling bearings 41 and 42. The fourth gear 33, to which the reduction gear output shaft 37 is attached and fixed, is rotatably supported with respect to the casing 22 by rolling bearings 43 and 44. The outboard side shaft portion 45 of the reducer output shaft 37 is connected to the hub wheel 47 of the wheel bearing portion C by spline fitting, and the output of the reducer portion B is connected to the rear wheel 14 (see FIGS. 8 and 9). introduce.

  The 1st gearwheel 30-the 4th gearwheel 33, and the rotating shaft of each gearwheel are demonstrated based on FIG. FIG. 2 is a schematic view of only the first gear 30 to the fourth gear 33 constituting the parallel shaft gear reducer 39 of FIG. 1 as viewed from the outboard side.

  The first gear 30 is attached and fixed to the motor rotation shaft 25 (see FIG. 1), and rotates about its axis C1. The second gear 31 is attached and fixed to the intermediate shaft 35 (see FIG. 1), and the third gear 32 is formed integrally with the intermediate shaft 35 and rotates about its axis C2. The fourth gear 33 is fixedly attached to the speed reducer output shaft 37 (see FIG. 1), and rotates around its axis C3. In addition, since the motor rotating shaft 25 and the reduction gear output shaft 37 are arrange | positioned coaxially, each axial center C1 and axial center C3 correspond.

  In this embodiment, the shaft centers C1, C2, and C3 of the motor rotating shaft 25, the intermediate shaft 35, and the speed reducer output shaft 37 are arranged on a straight line EE, so that the speed reducer portion B is made compact in the radial direction. ing. However, the arrangement of the shaft centers C1, C2, and C3 is not limited to the arrangement as in this embodiment, and is appropriately shifted in consideration of the space of the casing 22 while maintaining the meshing of the gears 30 to 33. May be.

  Here, helical gears are used for the first gear 30 to the fourth gear 33 constituting the parallel shaft gear reducer 39. Helical gears are effective in that the number of teeth engaged simultaneously increases and the tooth contact is dispersed, so that the sound is quiet and torque fluctuation is small. In consideration of the meshing ratio of gears and the limit number of rotations, the number of modules is preferably about 1 to 3.

  Since the in-wheel motor drive device 21 is housed inside the wheel housing 15 (see FIG. 9) and becomes an unsprung load, a reduction in size and weight is essential. The electric motor 26 can be miniaturized by combining the parallel shaft gear reducer 39 with the electric motor 26. For example, when the parallel shaft gear reducer 39 having a reduction ratio of 11 is used, the electric motor 26 can be reduced in size by using the electric motor 26 that rotates at a high speed of about ten thousand rotations per minute. In this case, considering the space of the casing 22 and the like, the reduction ratio of the first stage consisting of the first gear 30 and the second gear 31 is about 2 to 4, and the second stage consisting of the third gear 32 and the fourth gear 33. The reduction ratio is preferably about 3 to 5.

  As shown in FIG. 1, the wheel bearing portion C includes a wheel bearing 46 having the following structure. The wheel bearing 46 is disposed on the outer side of the hub wheel 47 and the inner ring 48, the hub wheel 47 connected to the reduction gear output shaft 37 so as to transmit torque, the inner ring 48 fitted to the outer periphery of the hub wheel 47. This is a double-row angular ball bearing including an outer ring 49, a plurality of balls 50 disposed between the hub ring 47 and the inner ring 48 and the outer ring 49, and a cage 51 that holds the plurality of balls 50. Seal members 52 are provided at both ends in the axial direction of the wheel bearing 46 to prevent intrusion of muddy water and the like and leakage of grease.

  The wheel bearing 46 is fastened and fixed to the parallel shaft gear reducer 39 by screwing a nut 53 into a male screw portion formed at the end of the outboard side shaft portion 45 of the reducer output shaft 37. . An outer ring 49 of the wheel bearing 46 is fixedly attached to the casing 22. The inner ring 48 of the wheel bearing 46 is prevented from coming off by coming into contact with the flange portion 54 of the reduction gear output shaft 37. The rear wheel 14 (see FIGS. 8 and 9) is connected to the hub wheel 47 of the wheel bearing 46 by a hub bolt 55.

  Next, the lubrication structure in the in-wheel motor drive device 21 will be described. Lubricating oil is enclosed in the speed reducer part B in order to cool and lubricate the parallel shaft gear speed reducer 39. The XX line of FIG. 1 shows the oil level of the lubricating oil in the reduction gear part B when the in-wheel motor drive device 21 is stopped. The lubricating oil is stored in the lower part of the casing 22 in the speed reducer part B, and the oil level is in the vicinity of the axis of the intermediate shaft 35. Therefore, the substantially lower half of the second gear 31 and the third gear 32 is in a state of being immersed in the lubricating oil.

  At the time of driving the in-wheel motor drive device 21, the reduction gear section B uses the lubricating oil stored in the lower part of the casing 22 to cause the first gear 30, the second gear 31, the third gear 32, The parallel shaft gear reducer 39 is cooled and lubricated by splashing by the rotation of the fourth gear 33.

  For the motor part A, for example, lubricating oil is supplied from the rotary pump (not shown) to the rotor 24 and the stator 23 of the electric motor 26 via the oil passage (not shown) of the casing 22 and the motor rotating shaft 25. A cooling structure consisting of an axial oil supply structure to be supplied is possible. Another structure may be sufficient as the cooling structure of the motor part A, and the structure is arbitrary.

  The overall configuration of the in-wheel motor drive device 21 in this embodiment is as described above, and the characteristic configuration will be described in detail below.

  In the speed reducer part B, the first gear 30 of the parallel shaft gear speed reducer 39 connected to the motor rotation shaft 25 of the electric motor 26 rotates at a high speed of about 10,000 thousand revolutions per minute, and is located below the casing 22. It exists in the position away from the oil surface (refer XX line of FIG. 1) of the lubricating oil to store. Therefore, lubrication is important when the in-wheel motor drive device 21 is started, for example, when the electric motor 26 is restarted after a certain period of time after it stops. If it is difficult to lubricate the first gear 30 by splashing due to the rotation of the gear when the motor is restarted, the first gear 30 may be damaged, such as seizure.

  Therefore, in this embodiment, as shown in FIGS. 1 and 3, after the lubricating oil is stored by splashing by the rotation of the first gear 30 and the second gear 31, the lubricating oil is dropped onto the first gear 30. A saucer-like oil reservoir 56 is disposed above the first gear 30. The oil reservoir 56 is attached and fixed to the wall surface 57 of the casing 22 and is disposed above the first gear 30.

  A dripping port 58 is provided at the bottom of the oil reservoir 56 so that the stored lubricating oil can be dripped. The dripping port 58 has a funnel shape that can narrow down the lubricating oil so that the lubricating oil can be dripped little by little. In this embodiment, although the funnel-shaped dripping port 58 is disclosed, the present invention is not limited to this, and the shape of the dripping port 58 is arbitrary, and the lubricating oil is dripped depending on the shape and the diameter. The amount can be adjusted.

  In the speed reducer part B of this embodiment, the lubricating oil that is stored in the lower part of the casing 22 and in which a part of the second gear 31 is immersed is used when the electric motor 26 is driven, such as when the vehicle is running. The lubricating oil splashed by splashing by the rotation of the first gear 30 and the second gear 31 (see the solid line arrow in FIG. 3) is stored in the oil reservoir 56 (see the broken line arrow in FIG. 3).

  On the other hand, when the electric motor 26 is restarted after being stopped, the lubricating oil stored in the lower part of the casing 22 and immersed in a part of the second gear 31 is used, so that the second gear 31 can be splashed by rotation. Even if it is difficult to lubricate the first gear 30, as shown in FIG. 4, the lubricating oil 59 stored in the oil reservoir 56 when the electric motor 26 is driven is dripped from the dripping port 58 to the first gear 30. . In this way, the lubricating of the first gear 30 can be assisted with the lubricating oil 59 dripping from the oil reservoir 56.

  As in this embodiment, by providing a dripping port 58 that opens toward the first gear 30 at the bottom of the oil reservoir 56, the oil reservoir 56 stores the oil when the electric motor 26 is restarted after the stop. Thus, the lubricating oil 59 can be reliably dropped from the dropping port 58 to the first gear 30.

  As another embodiment, as shown in FIG. 5, an electromagnetic valve 60 that opens and closes the dripping port 58 and controls the dripping of the lubricating oil 59 onto the first gear 30 is provided at the bottom of the oil reservoir 56. It may be. The electromagnetic valve 60 includes a valve portion 61 that opens and closes a dripping port 58 at the bottom of the oil reservoir portion 56 and a solenoid portion 62 that drives the valve portion 61 to open and close.

  Thus, the structure employing the electromagnetic valve 60 capable of opening / closing control is effective when the electric motor 26 is restarted after a long period of time has elapsed since the electric motor 26 was stopped. That is, when the electric motor 26 is driven, the lubricating oil 59 scattered by splashing by the rotation of the first gear 30 and the second gear 31 when the electromagnetic valve 60 is closed is stored in the oil reservoir 56 (see FIG. 5). .

  Even after a long time has elapsed since the electric motor 26 was stopped, the lubricating oil 59 is stored in the oil reservoir 56 with the electromagnetic valve 60 closed. Therefore, when the electric motor 26 is restarted, as shown in FIG. 6, the lubricating oil 59 stored in the oil reservoir 56 with the electromagnetic valve 60 opened is dropped from the dropping port 58 to the first gear 30. In this way, the lubricating of the first gear 30 can be assisted with the lubricating oil 59 dripping from the oil reservoir 56.

  The opening / closing control of the electromagnetic valve 60 as described above can be performed based on the flowchart shown in FIG.

  When the ignition motor is turned on when the electric motor 26 is started (STEP 1), the electromagnetic valve 60 is opened (STEP 2). When the electromagnetic valve 60 is opened, the lubricating oil 59 stored in the oil reservoir 56 is dropped from the dropping port 58 to the first gear 30 as described above. In this way, the lubricating of the first gear 30 is assisted by the lubricating oil 59 dripping from the oil reservoir 56.

  Then, when 15 seconds have passed since the electromagnetic valve 60 was opened and when the vehicle speed is 25 km / h or more by driving the electric motor 26 (STEP 3), the electromagnetic valve 60 is closed (STEP 4). By closing the electromagnetic valve 60, the lubricating oil 59 is stored in the oil reservoir 56 as described above. Thereafter, when the electric motor 26 is stopped, the ignition is turned off (STEP 5) to return to the initial state.

  Note that the determination condition including the elapsed time since the electromagnetic valve 60 is opened and the vehicle speed is an example, and can be changed as appropriate according to the usage mode of the in-wheel motor drive device 21.

  Finally, the overall operation principle of the in-wheel motor drive device 21 in this embodiment will be described.

  As shown in FIG. 1, in the motor part A, for example, the rotor 24 rotates by receiving electromagnetic force generated by supplying an alternating current to the stator 23. Thereby, in the speed reducer part B, the rotation of the motor rotating shaft 25 is decelerated by the first gear 30, the second gear 31, the third gear 32 and the fourth gear 33 that constitute the parallel shaft gear speed reducer 39. It is transmitted to the wheel bearing portion C via the machine output shaft 37. At this time, since the rotation of the motor rotating shaft 25 is decelerated by the reducer part B and transmitted to the reducer output shaft 37, even when the low torque, high speed rotating type electric motor 26 is employed in the motor part A, It is possible to transmit the necessary torque to the rear wheel 14 (see FIGS. 8 and 9).

  The reduction ratio of the reduction gear section B is 1 / 2.5 at the first stage of the first gear 30 and the second gear 31 and 1 / 4.5 at the second stage of the third gear 32 and the fourth gear 33. For example, the reduction ratio can be as large as about 1/11. Thus, by adopting the parallel shaft gear reducer 39 capable of obtaining a large reduction ratio, a compact and high reduction ratio in-wheel motor drive device 21 can be obtained. Further, since the parallel shaft gear reducer 39 uses a helical gear, it is easy to manufacture, the cost can be reduced, and the in-wheel motor drive device 21 that is quiet and efficient in terms of performance is realized. Can do.

  In this embodiment, the radial gap type electric motor 26 is exemplified as the motor portion A, but a motor having an arbitrary configuration is applicable. For example, an axial gap type electric motor including a stator fixed to a casing and a rotor arranged so as to face the inner side in the axial direction of the stator with a gap may be used.

  The description of the operation in this embodiment has been made by paying attention to the rotation of each member, but in reality, power including torque is transmitted from the motor part A to the rear wheel 14. Therefore, the power decelerated as described above is converted to high torque. Also, the case where power is supplied to the motor unit A to drive the motor unit and the power from the motor unit A is transmitted to the rear wheels 14 is shown. On the contrary, the vehicle decelerates or goes down the hill. In such a case, the power from the rear wheel 14 side may be converted into high-rotation low-torque rotation by the reduction gear part B and transmitted to the motor part A, and the motor part A may generate power. Furthermore, the electric power generated here may be stored in a battery and used later for driving the motor unit A or for operating other electric devices provided in the vehicle.

  In this embodiment, as shown in FIGS. 8 and 9, the electric vehicle 11 having the rear wheel 14 as a driving wheel is illustrated, but the front wheel 13 may be a driving wheel or a four-wheel driving vehicle. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and includes, for example, a hybrid vehicle.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

21 In-wheel motor drive device 22 Casing 25 Motor rotating shaft 30 Input gear (first gear)
39 Parallel shaft gear reducer 56 Oil reservoir 58 Drip port 60 Electromagnetic valve A Motor part B Reducer part C Wheel bearing part

Claims (3)

A motor part, a speed reducer part composed of a parallel shaft gear speed reducer composed of a plurality of gears, and a wheel bearing part, and a spring caused by the rotation of the gear of the parallel shaft gear speed reducer in an oil bath state without a pump An in-wheel motor drive device that lubricates each gear by hanging,
The parallel shaft gear reducer includes an input gear that is coaxially connected to a shaft end of a motor rotation shaft of a motor unit, and stores the lubricating oil by splashing by rotation of a plurality of gears. An in-wheel motor drive device characterized in that an oil reservoir portion dripping onto an input gear is disposed above the input gear.   2. The in-wheel motor drive device according to claim 1, wherein the oil reservoir portion is provided with a dripping port that opens toward the input gear at a bottom portion thereof.   3. The in-wheel motor drive device according to claim 2, wherein the oil reservoir portion is provided with an electromagnetic valve that controls the dripping of the lubricating oil onto the input gear by opening and closing the dripping port at the bottom thereof.

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