JP2012201289A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor drive device capable of preventing interference with a suspension device and a brake device, by miniaturizing a transmission mechanism for transmitting rotation of rotary electric machinery onto a second axis parallel to a first axis from the first axis by reducing a speed.SOLUTION: This in-wheel motor drive device 1includes a motor 3, a reduction gear mechanism 20 for transmitting rotation of the motor 3 onto the second axis AX2 from the first axis AX1 by reducing the speed, a reduction planetary gear 40 for reducing a speed of the rotation transmitted by the reduction gear mechanism 20, and an output shaft 50 for outputting decelerated rotation of the reduction planetary gear 40 to a wheel. In the reduction gear mechanism 20, an idler gear 22 meshing with a small diameter gear 21 and a large diameter gear 25a is arranged on a third axis AX3 parallel to the first axis AX1 and the second axis AX2. The sufficient reduction gear ratio is set by the reduction gear mechanism 20, and the large diameter gear 25a can be diametrically reduced, so that the in-wheel motor drive device 1can be miniaturized.

Description

  The present invention relates to an in-wheel motor drive device mounted on, for example, a hybrid vehicle, an electric vehicle, and the like. Specifically, the rotation of a rotating electrical machine disposed on a first axis is on a second axis parallel to the first axis. The in-wheel motor drive device which transmits to the speed-reduction mechanism and output shaft which are arrange | positioned in the.

  In recent years, various vehicles equipped with motor generators (hereinafter simply referred to as “motors”) such as hybrid vehicles and electric vehicles have been proposed in order to improve vehicle fuel efficiency and environmental performance. In a vehicle equipped with a motor, it is arranged in the wheel of the wheel in order to secure the interior space, improve the drive / regeneration efficiency, or reduce the weight by omitting the axle shaft and differential device. Development of an in-wheel motor drive device to be installed is underway (see Patent Document 1).

JP 2009-126189 A

  However, as in Patent Document 1, in the case where the motor (traction motor 20) and the speed reduction mechanism (speed reducer 30) are arranged coaxially with the center axis of the wheel, the axial length becomes longer, so the motor has a wheel width. It protrudes larger and oozes out to the vehicle side. If the vehicle intrudes into the vehicle in this way, it interferes with the suspension device of the vehicle not provided with the in-wheel motor drive device, so a new suspension device is developed for mounting the in-wheel motor drive device. There is a problem that necessity arises and a significant cost increase including vehicle design occurs.

  Therefore, in order to shorten the axial direction, the speed reduction mechanism and the motor are arranged on parallel axes, and the speed reduction mechanism and the motor are arranged so as to overlap in the axial direction when viewed from the radial direction. It is considered by the present applicant to construct a biaxial in-wheel motor drive device that is U-shaped in cross-sectional view.

  By the way, even in the case of the biaxial configuration in this way, if the diameter of the motor is increased in order to improve the output of the motor, the radial direction of the in-wheel motor drive device is expanded, There is a risk of interference with a brake device or a suspension device (for example, a hub arm) disposed in the wheel. For this reason, in a transmission mechanism that transmits power between the motor and the speed reduction mechanism, it is conceivable to set a gear ratio so as to further reduce the speed and to reduce the size of the motor.

  However, in such a transmission mechanism that transmits power between the motor and the reduction mechanism, in order to set the reduction ratio, the reduction mechanism is driven rather than the first gear that is drivingly connected to the rotor of the motor. It is necessary to increase the diameter of the second gear to be connected. And in order to mesh | engage these 1st and 2nd gears, unless the diameter of a 2nd gear is enlarged rather than a speed reduction mechanism, it will not reach a 1st gear, but this 2nd gear is more than a speed reduction mechanism. When the diameter becomes large, the portion eventually becomes enlarged, and there is a problem in that it may interfere with a brake device, a suspension device, or the like.

  Therefore, the present invention reduces the size of a transmission mechanism that decelerates and transmits the rotation of a rotating electrical machine from a first axis to a second axis parallel to the first axis, thereby interfering with a suspension device, a brake device, and the like. An object of the present invention is to provide an in-wheel motor drive device that can be prevented.

The present invention (see, for example, FIGS. 1 to 5) is an in-wheel motor drive device (1) that is attached to the inside of a wheel of a wheel and can drive the wheel.
A rotating electrical machine (3) disposed on the first axis (AX1);
A transmission mechanism (20) for decelerating and transmitting the rotation of the rotating electrical machine (3) from the first axis (AX1) to a second axis (AX2) parallel to the first axis (AX1);
A speed reduction mechanism (40) disposed on the second axis (AX2) and decelerating the rotation transmitted by the transmission mechanism (20);
An output shaft (50) disposed on the second shaft (AX2) and outputting the reduced speed rotation of the speed reduction mechanism (40) to the wheel;
The transmission mechanism (20)
A first gear (21) disposed on the first shaft (AX1) and drivingly connected to the rotating electrical machine (3);
A second gear (25a) disposed on the second shaft (AX2) and drivingly connected to the speed reduction mechanism (40) and having a larger diameter than the first gear (21);
A third shaft (AX3) disposed on the third shaft (AX3) parallel to the first shaft (AX1) and the second shaft (AX2) and meshing with the first gear (21) and the second gear (25a). And a gear (22).

  In the present invention (see, for example, FIG. 3), the third axis (AX3) is arranged on a straight line (X) passing through the first axis (AX1) and the second axis (AX2). And

Further, according to the present invention (see, for example, FIGS. 1 to 5), the rotating electrical machine (3), the transmission mechanism (20), the speed reduction mechanism (40), and a part of the output shaft (50) are accommodated. Member (2);
Shaft members (23, 123) that pass through the center of the third gear (22) and rotatably support the third gear (22),
In the shaft member (23, 123), the rotating electrical machine (3) is disposed on one side in the axial direction, and the end portion (23c, 123d) on the other side in the axial direction is a support portion of the case member (2) ( 2e).

Furthermore, the present invention (see, for example, FIGS. 1 to 3) is a plate that is supported by the case member (2) and has a facing portion (24a) facing the support portion (2e) of the case member (2). Comprising a member (24),
The shaft member (23) is characterized in that one side in the axial direction is supported by a facing portion (24a) of the plate member (24).

Further, according to the present invention (see, for example, FIGS. 1 to 3), the rotating electrical machine (3) includes a stator (4) and a rotor (5),
The facing portion (24a) of the plate member (24) has a concave portion (24b) recessed in the axially opposite side of the stator (4) in a portion overlapping the stator (4) when viewed in the axial direction. And

Further, according to the present invention (see, for example, FIGS. 1, 2, and 4), the case member (2) has a groove portion (2d) that is formed in a groove shape and guides lubricating oil,
The shaft member (23) is formed so as to penetrate in the axial direction, and is formed so as to penetrate from the groove (2d) to the axial hole (23a) and from the axial hole (23a) toward the outer peripheral side. A radial hole (23b) for guiding lubricating oil to a bearing (b3) that rotatably supports the third gear (22), and a protrusion (23e) inserted into the groove (2d) of the case member (2) ).

Further, according to the present invention (see, for example, FIG. 1), the speed reduction mechanism (40) and the rotating electrical machine (3) are arranged at positions overlapping in the axial direction when viewed from the radial direction,
The first gear (21), the second gear (25a), and the third gear (22) of the transmission mechanism (20) are arranged at positions that overlap each other in the axial direction when viewed from the radial direction. And

  In addition, although the code | symbol in the said parenthesis is for contrast with drawing, this is for convenience for making an understanding of invention easy, and has no influence on the structure of a claim. It is not a thing.

  According to the first aspect of the present invention, the transmission mechanism has the third gear disposed on the third shaft parallel to the first shaft and the second shaft and meshing with the first gear and the second gear. Therefore, while the transmission mechanism can set a sufficient reduction ratio, the second gear of the transmission mechanism can be particularly reduced in diameter, and the transmission mechanism can be reduced in size. As a result, the in-wheel motor drive device can be reduced in size, and interference with the suspension device and the brake device can be prevented.

  According to the second aspect of the present invention, the third shaft is disposed on a straight line passing through the first shaft and the second shaft, that is, the first, second, and third gears are disposed linearly. Therefore, the thrust force received from the first gear with respect to the third gear and the thrust force received from the second gear with respect to the third gear are generated at the true reverse position in the circumferential direction in the third gear. Cancel each other without acting in the twisting direction. Thereby, the support structure of the third gear can be simplified, and the support structure of the third gear can be reduced in size.

  According to the third aspect of the present invention, the axial member on the other side in the axial direction of the shaft member that rotatably supports the third gear is supported by the support portion of the case member, so that the shaft member is moved to the one side in the axial direction. It can be possible to arrange the rotary electric machine at a place where the rotary electric machine is arranged.

  According to the fourth aspect of the present invention, the shaft member is supported by the opposing part of the plate member on one side in the axial direction of the axial member, so that the axial member is supported by the support part of the case member and the opposing part of the plate member. Can be. Thereby, the support precision of a 3rd gear can be improved and durability improvement and reduction of gear noise can also be aimed at.

  According to the fifth aspect of the present invention, since the opposing portion of the plate member overlaps with the stator of the rotating electrical machine when viewed in the axial direction, the concave portion is recessed in the opposite axial direction to the stator. The rotating electric machine and the plate member can be brought closer to the axial direction by the amount of the depression. Thereby, an in-wheel motor drive device can be shortened to an axial direction.

  According to the sixth aspect of the present invention, the shaft member is formed in the axial hole through which the lubricating oil is introduced from the groove portion, and the bearing that penetrates from the axial hole toward the outer peripheral side and rotatably supports the third gear. A groove formed to guide the lubricating oil for lubricating the bearing that rotatably supports the third gear, since it has a radial hole for guiding the lubricating oil and a protrusion inserted into the groove of the case member Thus, the shaft member can be prevented from being rotated by the projection, that is, it is unnecessary to separately provide a part dedicated to the rotation prevention.

  According to the seventh aspect of the present invention, since the speed reduction mechanism and the rotating electrical machine are arranged at positions overlapping in the axial direction when viewed from the radial direction, the rotating electrical machine does not protrude toward the vehicle side, and the in-wheel motor drive The device can be shortened in the axial direction. In addition, since the first gear, the second gear, and the third gear of the transmission mechanism are also arranged at positions that overlap each other in the axial direction when viewed from the radial direction, the transmission mechanism does not swell in the axial direction, and in-wheel The motor drive device can be shortened in the axial direction.

The front sectional view showing the in-wheel motor drive concerning a 1st embodiment. Side surface sectional drawing which shows the in-wheel motor drive device which concerns on 1st Embodiment. AA arrow sectional drawing of FIG. The perspective view which shows an idler axis | shaft. Front sectional drawing which shows a part of in-wheel motor drive device which concerns on 2nd Embodiment.

<First Embodiment>
A first embodiment according to the present invention will be described below with reference to FIGS. Incidentally, the in-wheel motor drive device 1 ₁ of the present embodiment, but is used as a driving device for changing the four-wheel drive vehicle is attached to the wheel of the rear wheel in a hybrid vehicle of front-wheel drive, it Besides, for example, a drive device for an electric vehicle, a drive device for a series hybrid vehicle, a drive device for changing to a four-wheel drive vehicle by mounting in a front wheel of a rear-wheel drive hybrid vehicle, etc. Can do.

This in-wheel motor drive device 1 _1, as shown in FIG. 1, a case (case member) 2, roughly, a motor-generator (rotating electric machine) 3, a reduction gear mechanism (transmission mechanism) 20, the reduction planetary gear ( (Deceleration mechanism) 40, an output shaft 50 to which a wheel hub 51 is fixed, and the like. Of these, the motor generator 3 (hereinafter simply referred to as “motor 3”) is disposed on the first axis AX1, and the output shaft 50 and the reduction planetary gear 40 are coaxial with the center of the wheel 100, which will be described in detail later. The second axis AX2 is parallel to the first axis AX1. The reduction gear mechanism 20 is arranged such that its transmission path extends in a direction perpendicular to the axial direction, and an idler gear 22 and an idler shaft 23 described later in detail are parallel to the first axis AX1 and the second axis AX2. It is arranged on the three axes AX3. Thereby, the transmission path formed by the motor 3, the reduction gear mechanism 20, the reduction planetary gear 40, and the output shaft 50 is configured to have a U shape in a cross-sectional view.

  The case 2 accommodates most of the main parts, and has a bearing support portion 2f of a hub bearing 52, which will be described in detail later, and a main case 2A opened on the opposite side to the bearing support portion 2f in the axial direction. And a case cover 2B for closing the opening of the main case 2A. The main case 2A and the case cover 2B are fastened by a bolt 11 that is screwed into the hole 2Ah of the main case 2A and the hole 2Bh of the case cover 2B.

  In addition, the case 2 forms a sealing structure in which oil is sealed by sealing an outer peripheral side of an output shaft 50 described later in detail with a seal ring 55. That is, the case 2 houses the motor 3, the reduction gear mechanism 20, the reduction planetary gear 40, a part of the output shaft 50, and the like, and encloses oil to form an oil reservoir on the lower side inside the case 2. Yes. The oil sump is formed at a lower portion than the second shaft AX2, and a part of a large-diameter gear 25a of a reduction planetary gear 40 and a reduction gear shaft 25, which will be described in detail later, is immersed and located above. The motor 3 is lubricated and cooled by oil (lubricating oil) scraped up by the rotation of the speed reduction planetary gear 40 and the large diameter gear 25a without being immersed in the oil reservoir. Therefore, normally, the motor 3 is not immersed in the oil reservoir, and no oil stirring loss occurs in the motor 3.

  As described above, the motor 3 is disposed in the upper part of the main case 2A. The motor 3 includes a stator 4 fixed to the case 2 and a rotor 5 fixed on a rotor shaft 7 which is on the first axis AX1 and is rotatably supported by the case 2. The rotor 5 is composed of a so-called induction motor in which no permanent magnet is embedded. The stator 4 includes a stator steel plate 4a formed by laminating a large number of steel plates, and a large number of stator windings inserted into a plurality of slits (not shown) formed in the stator steel plate 4a. (Hereinafter, simply referred to as “axial direction”) that have coil ends 4b and 4b that are portions that protrude and fold back. That is, the laminated stator steel plates 4a have a substantially cylindrical shape, and a stator coil is formed by winding a stator winding around a slit formed in the cylindrical portion, and both ends of the stator steel plate 4a are stators. Coil ends 4b and 4b of the coil are formed. The stator steel plate 4a has a fixing portion (not shown) fastened to the case 2 with bolts or the like.

  On the other hand, the rotor 5 has a cylindrical rotor core 5a configured such that steel plates are laminated in the same manner as the stator steel plate 4a and, for example, an induced current is generated. On both sides in the axial direction of the rotor core 5a, annular end plates 6A and 6B are disposed, and the end plate 6A is in contact with a flange portion 7a formed on the rotor shaft 7. Further, the end plate 6B is fastened to the flange portion 7a by a nut 8 screwed to the rotor shaft 7, whereby the rotor core 5a is integrally fixed on the rotor shaft 7.

  The rotor shaft 7 has a so-called both-end supported structure by a ball bearing b1 fitted to the annular portion of the inner surface of the main case 2A and a ball bearing b2 fitted to the annular portion of the inner surface of the case cover 2B. It is supported so that it can rotate freely. On the rotor shaft 7, a small-diameter gear (first gear) 21 serving as a reduction gear mechanism 20 is provided in parallel with the rotor core 5a in the axial direction. In addition to being disabled (that is, drivingly connected), the small-diameter gear 21 is fastened to the stepped portion 7b of the rotor shaft 7 by the nut 9 together with the ball bearing b2.

  The reduction gear mechanism 20 is formed with the small-diameter gear 21 fixed to the rotor shaft 7 and the helical tooth surface 22a that meshes with the helical tooth surface 21a of the small-diameter gear 21. A large-diameter gear (second gear) 25a of a reduction gear shaft 25 formed with an idler gear (third gear) 22 and a helical tooth surface 25b that meshes with a helical tooth surface 22a of the idler gear 22. And is configured. Of these, an idler gear 22 described later in detail is disposed on a third axis AX3 parallel to the first axis AX1 and the second axis AX2 described later, and an idler shaft disposed on the third axis AX3. A (shaft member) 23 is rotatably supported via a needle bearing (bearing) b3.

  The large-diameter gear 25a of the reduction gear shaft 25 is arranged in parallel on the second axis AX2 together with the reduction planetary gear 40 and the output shaft 50, and the outer peripheral surface of the portion formed in a flange shape from the reduction gear shaft 25 is the idler gear. By being formed as a tooth surface 25 b that meshes with the tooth surface 22 a of 22, it is configured as a gear that is drivingly connected to a reduction planetary gear 40 described later. The reduction gear shaft 25 on the second axis AX2 is on the axis parallel to and below the rotor shaft 7 on the first axis AX1, and one end is rotatable with respect to the case 2 by the ball bearing b4. While being supported, the other end is rotatably supported by the ball bearing b5 with respect to the case 2 via an output shaft 50 and a hub bearing 52, which will be described in detail later. The large-diameter gear 25a transmits the rotation of the motor 3 through the idler gear 22 and the small-diameter gear 21. A tooth surface of the sun gear 25c of the reduction planetary gear 40 is formed on the outer peripheral surface of the reduction gear shaft 25 on the output shaft 50 side in the axial direction.

  As shown in FIG. 2, the reduction gear mechanism 20 is arranged such that the centers of the small-diameter gear 21, the idler gear 22, and the large-diameter gear 25a are in a straight line when viewed from the side (that is, the first axis AX1, the second axis). The axis AX2 and the third axis AX3 are arranged on the straight line X), and as shown in FIG. 1, also in the axial direction (in front view), the motor 3, the reduction planetary gear 40, and the side surface of the case cover 2B It arrange | positions so that it may be on a straight line along.

  The speed reduction planetary gear 40 is disposed at a position overlapping the motor 3 in the axial direction when viewed from the radial direction, the above-described sun gear 25c, a pinion gear 43 formed with a tooth surface 43a meshing with the sun gear 25c, And a ring gear 41 formed with a tooth surface 41 a that meshes with the tooth surface 43 a of the pinion gear 43. The pinion gear 43 is rotatably supported by a pinion shaft 44 spanned between the side plate 42 and the flange portion 50d of the output shaft 50, and is integrated by the pinion gear 43, the pinion shaft 44, the side plate 42, and the flange portion 50d. A carrier 46 is configured. In the ring gear 41, a spline 41s formed on the outer peripheral side of the ring gear 41 is spline-engaged with a spline 2s formed on a cylindrical portion formed along the inner peripheral surface of the main case 2A. It is fixed so that it cannot rotate while being sandwiched between the main case 2A.

  As described above, the output shaft 50 is formed with the flange-shaped flange portion 50d constituting a part of the carrier 46 at the end portion on the axial reduction planetary gear 40 side, and the reduction planetary gear of the flange portion 50d. 40 is formed as a large-diameter portion 50c having a large diameter on the side opposite to the axial direction, an intermediate portion is formed as a small-diameter portion 50b having a smaller diameter than the large-diameter portion 50c, and a tip having a smaller diameter than the small-diameter portion 50b at the tip portion. A portion 50a is formed. The ball bearing b5 is inserted between the large-diameter portion 50c and the reduction gear shaft 25.

  A sleeve 54 is fitted to the outer peripheral surface of the large-diameter portion 50c of the output shaft 50, and a seal ring 55 is disposed between the sleeve 54 and the inner peripheral surface of the main case 2A. Ensuring the tightness of the reservoir and preventing intrusion of relics from the outside. Further, a tooth surface 54a is formed on the outer peripheral surface of the sleeve 54 in the axial direction on the speed reduction planetary gear 40 side, and a rotation speed sensor 59 that detects the passage of teeth on the tooth surface 54a facing the tooth surface 54a. Is arranged. Since the rotation speed sensor 59 detects the rotation of the wheel fixed via the output shaft 50, it can be used as a speed sensor, an ABS rotation speed sensor, or the like.

  On the other hand, a wheel hub 51 is spline-fitted to the outer peripheral surface of the small-diameter portion 50b of the output shaft 50, and the wheel hub 51 is screwed onto a tip portion 50a of the output shaft 50. It is secured. A hub bearing 52 is fitted to the outer peripheral side of the sleeve portion 51a formed in the hollow shape of the wheel hub 51 between the bearing support portion 2f of the main case 2A, that is, the wheel hub 51 and the output shaft. 50 is rotatably supported with respect to the case 2. The hub bearing 52 is sandwiched between the snap ring 56 and the bearing support portion 2f of the main case 2A. The hub bearing 52 abuts against the side surface of the sleeve 54, and the distal end on the opposite side of the sleeve 54 has the flange portion 50d. The positioning support accuracy in the axial direction of the output shaft 50 is ensured satisfactorily.

  A hub portion 51b formed in a disk shape is provided at an end portion in the axial direction of the wheel hub 51, and bolts (not shown) are inserted into a plurality of bolt holes formed in the hub portion 51b. A wheel is fastened to these bolts with a nut to form a wheel.

A caliper mounting portion 2g is integrally extended on the outer peripheral side of the bearing support portion 2f of the main case 2A, and a caliper of a disc brake device (not shown) is fixed to the caliper mounting portion 2g. The The caliper is arranged in parallel on the same diameter as the motor 3 in the circumferential direction around the second axis AX2 that is the center of the output shaft 50 (the center of the wheel). Further, in the main case 2A, a hub arm mounting portion of the suspension device is formed (not shown) so as to be arranged in parallel on the same diameter as the motor 3 in the circumferential direction around the second axis AX2. Therefore, in the wheel, the caliper, the motor 3 and the hub arm mounting portion are arranged in order around the output shaft 50 and the reduction planetary gear 40. With such arrangement, the disk brake device (caliper) and suspension device, for example, to a vehicle which is not provided with an in-wheel motor drive device 1 _1, without significant design change, substantially intact Can be arranged.

Subsequently, the lubrication structure of the in-wheel motor drive device 1 _1, a flow of oil (lubricating oil) caused by the operation of the in-wheel motor drive device 1 ₁ will be described. As shown in FIGS. 1 and 2, on the inner surface of the case cover 2B, a rib portion 2a is integrally formed above the rotor shaft 7 so as to protrude toward the motor 3 in the axial direction. Yes. The lower side of the rib portion 2a is bent toward the direction in which the oil is picked up, thereby forming a collecting surface 2b for collecting the picked up oil. An oil hole 2c is formed from the lower end portion of the collection surface 2b so as to incline toward the opposite side of the motor 3 in the axial direction and downward. The oil hole 2c communicates with a space 2D between the tip of the rotor shaft 7 and the case cover 2B. Further, a groove portion 2d is formed on the inner surface of the case cover 2B so as to pass through the third axis AX3 and the second axis AX2 downward from the space 2D. Has been.

  For example, when a control unit (not shown) starts powering control of the motor 3 based on a driver's accelerator operation or the like, power is supplied to the stator 4 of the motor 3 from a power source (battery), an inverter circuit, etc., and the rotor 5 is rotationally driven. Is done. Then, the rotor shaft 7 is rotationally driven, and the rotation of the rotor shaft 7 is decelerated and transmitted from the small diameter gear 21 to the large diameter gear 25a of the reduction gear shaft 25 via the idler gear 22. Further, when the sun gear 25c of the reduction gear shaft 25 is driven to rotate, in the reduction planetary gear 40, the carrier 46 is further reduced through a ring gear 41 whose rotation is fixed, and the reduced rotation of the carrier 46 is output. It is transmitted to the shaft 50 and the wheel hub 51, and the wheel 200 is rotationally driven as a driving rotation.

  On the other hand, for example, when a control unit (not shown) starts regenerative control based on the driver's accelerator operation, brake operation, or the like, the output shaft 50 and the wheel hub 51 are rotationally driven by the inertia force of the vehicle and the like, and the deceleration planetary gear 40 The sun gear 25c of the reduction gear shaft 25 is rotated at an increased speed through the ring gear 41 whose rotation is fixed so as to be reversely input to the carrier 46. Further, the rotation of the reduction gear shaft 25 is transmitted to the small diameter gear 21 through the large diameter gear 25a and the idler gear 22 as a speed increasing rotation, the rotor shaft 7 is driven to rotate, and the stator 4 is set to a negative voltage so that the rotor 5 The counter electromotive force acts on the stator 4 and the electric power is supplied to the power source through the inverter circuit or the like, so that the power source is charged.

Since the motor 3 of the in-wheel motor drive device 11 in the _first embodiment is composed of an induction motor as described above, other wheels (for example, front wheels) are driven by, for example, a hybrid drive device (not shown). Even when the motor 3 is idling without powering control in the traveling state, the back electromotive force is not generated, and particularly in the high speed traveling where the motor 3 is at high speed, There is no need to perform so-called weak magnetic field control that cancels the torque generated by electric power, thereby improving the fuel efficiency of the vehicle.

  Thus, even when the motor 3 is power-running or regeneratively controlled, the rotation direction of the output shaft 50 is forward rotation when the vehicle is traveling forward, that is, the large-diameter gear 25a of the reduction gear shaft 25. The rotation direction of the carrier 46 of the reduction planetary gear 40 is one direction. In this forward traveling state, as shown in FIG. 2, the large-diameter gear 25a of the reduction gear shaft 25 rotates in the direction indicated by the arrow ω, and the oil in the oil reservoir on the lower side is directed upward by the large-diameter gear 25a. It is scraped up.

  Most of the oil thus scraped up is directly applied to the tooth surface of each gear of the reduction gear mechanism 20 and the motor 3 to lubricate and cool the reduction gear mechanism 20 and the motor 3. A part of the oil that has been scraped up is collected on the collecting surface 2b of the rib portion 2a and guided to the space 2D from the oil hole 2c. The ball bearing b2 disposed in the space 2D is lubricated by the oil guided to the space 2D, and the ball bearing b1 is guided by the oil guided through the axial through hole 7c formed in the rotor shaft 7. Is lubricated. The oil that has lubricated the ball bearing b1 passes between the stator 4 of the motor 3 and the inner surface of the main case 2A, and is returned to the oil reservoir while lubricating and cooling the motor 3.

  On the other hand, the oil in the space 2D also flows downward through the groove 2d. Part of the oil flowing into the groove 2d is introduced into an axial hole 23a of an idler shaft 23, which will be described in detail later, and a radial hole 23b formed so as to penetrate from the axial hole 23a toward the outer peripheral side. Through the needle bearing b3 that rotatably supports the idler gear 22. The oil that has not entered the radial hole 23b from the axial hole 23a is discharged from the opening on the opposite side to the groove 2d in the axial direction, and returned to the oil reservoir.

  A part of the oil that has flowed downward from the idler shaft 23 through the groove 2d is returned to the oil pool while lubricating the ball bearing b4, and the remaining oil is formed on the reduction gear shaft 25. Guided through the axial through hole 25d, the ball bearing b5 is lubricated and returned to the oil sump.

  Next, the idler gear 22 and its supporting structure, which are essential parts of the present invention, will be described. The above-described idler gear 22 is rotatably supported by the idler shaft 23 via the needle bearing b3. As shown in FIGS. 1 to 3, the idler shaft 23 is disposed between the case cover 2 </ b> B and the coil end 4 b of the stator 4 of the motor 3, that is, on the one side in the axial direction of the idler shaft 23. Will be placed. Further, as shown in FIG. 4, the idler shaft 23 has a substantially hollow cylindrical shape. The idler shaft 23 has an axial hole 23a penetrating in the axial direction at the center. A radial hole 23b (see FIG. 1) penetrating from the axial hole 23a toward the outer peripheral side is formed.

  Further, when the idler shaft 23 is attached, an end portion (an end portion on the other side in the axial direction) 23c on the case cover 2B side is fitted into a support hole 2e formed in the case cover 2B. Supported for case 2. On the side of the case cover 2B in the axial direction from the end 23c, two upper and lower protrusions 23e, 23e are formed so as to be inserted into the groove 2d. The protrusions 23e, 23e are formed on the idler shaft. When 23 is fitted into the support hole 2e of the case cover 2B, it enters the groove 2d and engages the idler shaft 23 so as not to rotate with respect to the case 2.

  An end portion (end portion on one axial side) 23d on the motor 3 side of the idler shaft 23 is fitted and supported in a fitting hole 24f of the plate member 24 as shown in FIGS. Yes. The plate member 24 includes two pedestal portions 24d and 24d fixed to the inner peripheral surface of the case cover 2B, leg portions 24c and 24c bent substantially vertically from the pedestal portions 24d and 24d, An opposing portion 24a that is supported by the leg portions 24c and 24c and is disposed in parallel with the inner surface of the case cover 2B and faces the support hole 2e is configured. That is, the plate member 24 has a shape in which the idler gear 22, the idler shaft 23, and the needle bearing b <b> 3 are wrapped in a band shape with the leg portions 24 c and 24 c and the facing portion 24 a. Washers 26 and 26 are disposed between the inner surface of the case cover 2B and the idler gear 22 and the needle bearing b3, and between the idler gear 22 and the needle bearing b3 and the opposed portion 24a, respectively, and the idler gear 22 and the needle bearing b3. The axial direction is positioned and supported.

  As shown in FIGS. 2 and 3, the pedestal portions 24d and 24d are each formed with two bolt holes 24e (four in total), and are formed in the case cover 2B so as to penetrate the bolt holes 24e. The bolts 12 are screwed into the formed female screw portion 2Ba, so that the base portions 24d and 24d are fastened so as to be fixed to the case cover 2B. As a result, the facing portion 24 a of the plate member 24 is positioned and supported with respect to the case 2.

  On the other hand, on the case cover 2B side of the facing portion 24a, a fitting hole 24f for fitting into the end portion 23d of the idler shaft 23 is formed, whereby the idler shaft 23 has both end portions 23c and 23d. The case cover 2B is fitted into the support hole 2e and the fitting hole 24f of the opposing portion 24a of the plate member 24 to form a so-called doubly supported structure.

  Further, on the motor 3 side of the facing portion 24a, a concave portion 24b that is recessed on the opposite side in the axial direction from the stator 4 is formed in a portion overlapping the coil end 4b of the stator 4 in the axial direction. The depth of the recess 24b is formed such that the end surface of the idler shaft 23 on the motor 3 side is exposed, and the gap between the coil end 4b and the facing portion 24a of the plate member 24 is a predetermined insulation distance. It is formed to a depth. By having this insulation distance, the current flowing between the winding coils in the stator 4 is configured not to leak through the plate member 24. Further, the axial distance between the plate member 24 and the stator 4 can be shortened to the maximum as compared with the case where the concave portion 24b is not formed in the facing portion 24a.

  Since the recess 24b is formed to a depth at which the end face of the idler shaft 23 on the motor 3 side is exposed, the axial hole 23a is opened (see FIG. 2), and the axial hole extends from the groove 2d. The oil introduced into 23a but not introduced into the radial hole 23b is returned to the oil reservoir.

According to the in-wheel motor drive device 1 ₁ configured as described above, the reduction gear mechanism 20 is disposed on the third axis AX3 parallel to the first axis AX1 and the second axis AX2, small-diameter gear 21 and the large Since the idler gear 22 meshed with the diameter gear 25a is provided, a sufficient reduction ratio can be set by the reduction gear mechanism 20, but the diameter of the large diameter gear 25a of the reduction gear mechanism 20 is reduced. Thus, the reduction gear mechanism 20 can be reduced in size. Thus, Hakare in-wheel motor drive device 1 ₁ of miniaturization, it is possible to prevent interfering with the suspension device and the brake device.

  Further, the third axis AX3 is arranged on a straight line X passing through the first axis AX1 and the second axis AX2, that is, the small diameter gear 21, the idler gear 22, and the large diameter gear 25a are arranged linearly. Since the thrust force received from the small-diameter gear 21 with respect to 22 and the thrust force received from the large-diameter gear 25a with respect to the idler gear 22 are generated at the positions opposite to the circumferential direction in the idler gear 22, these thrust forces act in the twisting direction. You can cancel each other without having to. Thereby, the support structure of the idler gear 22 (that is, the idler shaft 23 and the plate member 24) can be simplified, and the support structure of the idler gear 22 can be reduced in size.

  Further, the end portion 23c on the case cover 2B side of the idler shaft 23 that rotatably supports the idler gear 22 is supported by the support hole 2e of the case 2, so that the motor 3 is disposed on the opposite side in the axial direction. It can be possible to place it at a location.

  Further, by supporting the motor 3 side of the idler shaft 23 on the facing portion 24a of the plate member 24, the idler shaft 23 is made to be a both-end supported structure by the support hole 2e of the case 2 and the facing portion 24a of the plate member 24. be able to. Thereby, the support accuracy of the idler gear 22 can be improved, durability can be improved, and gear noise can be reduced.

Furthermore, since the facing portion 24a of the plate member 24 has a recessed portion 24b that is recessed on the opposite side in the axial direction from the stator 4 at a portion overlapping the stator 4 of the motor 3 when viewed in the axial direction, the recessed portion 24b is recessed. Therefore, the motor 3 and the plate member 24 can be brought closer to the axial direction. Thus, it is possible to shorten the in-wheel motor drive device 1 ₁ in the axial direction.

  Also, an idler shaft 23 is formed so as to penetrate through an axial hole 23a for introducing oil from the groove 2d and toward the outer peripheral side from the axial hole 23a, and to guide the oil to a needle bearing b3 that rotatably supports the idler gear 22. Since it has the direction hole 23b and the protrusions 23e and 23e inserted into the groove 2d of the case 2, the groove formed to guide the oil for lubricating the needle bearing b3 that rotatably supports the idler gear 22 2d can be used to prevent the idler shaft 23 from being rotated by the protrusions 23e and 23e, that is, it is unnecessary to separately provide a dedicated component for preventing rotation.

In the present embodiment, since the reduction planetary gear 40 and the motor 3 are arranged at positions that overlap in the axial direction when viewed from the radial direction, the motor 3 does not protrude toward the vehicle side, and the in-wheel motor drive it is possible to shorten the device 1 ₁ in the axial direction. Further, since the small-diameter gear 21, the large-diameter gear 25a, and the idler gear 22 of the reduction gear mechanism 20 are also arranged at positions overlapping each other in the axial direction when viewed from the radial direction, the reduction gear mechanism 20 may swell in the axial direction. no, it is possible to shorten the in-wheel motor drive device 1 ₁ in the axial direction.

<Second Embodiment>
Next, a second embodiment in which the first embodiment is partially changed will be described with reference to FIG. In the description of the second embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and the description thereof is omitted.

  In the second embodiment, the motor 3 is changed from an induction motor to an IPM synchronous motor (magnet buried motor) as compared with the first embodiment described above. In addition, a resolver device 30 for detecting the rotational position of the rotor shaft 7 is attached in order to detect and control the exact rotational position of the motor 3 with the change of the motor 3. Further, in the second embodiment, the support structure of the idler gear 22 is changed as compared with the first embodiment described above, that is, the idler shaft 123 is replaced with the idler shaft 23 and the plate member 24. It is arranged.

In particular, the resolver apparatus 30 in the in-wheel motor drive unit 1 ₂ includes a resolver rotor 32 which is fastened by a nut 33 to the tip (distal end in FIG. 5 right side) of the nut 9 of the rotor shaft 7, Case And a resolver stator 31 fixed to the side surface of the cover 2B. The resolver stator 31 is housed in a resolver chamber 34 covered with a cover member 2C that is detachably fixed to the case cover 2B. The resolver apparatus 30, after the production of this in-wheel motor drive unit 1 _2, and remove the lid member 2C, the phase (angle) with respect to the rotor shaft 7 of the resolver rotor 32 by loosening the nut 33 so that the adjustment is possible It is configured.

In the present in-wheel motor drive unit 1 _2, it is possible to detect the rotational speed of the rotor shaft 7 by the resolver apparatus 30, the output shaft by multiplying the gear ratio of the reduction gear mechanism 20 and the speed reduction planetary gear 40 to the detection result Since the rotational speed of 50 can be calculated, the rotational speed sensor 59 can be omitted.

Thus the motor 3 is in-wheel motor drive device 1 ₂ constructed in accordance with the IPM synchronous motor, as compared with the induction motor in the first embodiment, the counter electromotive force when it was co-rotated at high speed rotation Therefore, although the so-called field-weakening control needs to be performed, the output torque of the motor 3 increases, so that the output performance of the driving force as a whole vehicle becomes high performance.

On the other hand, in this in-wheel motor drive unit 1 _2, idler 22 is supported to be rotatable by the idler shaft 123 via a needle bearing b3. The idler shaft 123 is formed so as to penetrate from a flange portion 123a extending outward from the outer peripheral surface on which the needle bearing b3 is disposed, a hole portion 123b formed to be recessed in the center, and a bottom surface of the hole portion 123b. A bolt hole 123c, and the idler shaft 123 is attached to the case cover 2B by a bolt 124 screwed into the female screw portion 2Bb of the case cover 2B so as to penetrate the bolt hole 123c. Is fixed. Further, the end portion (end portion on the other side in the axial direction) 123d of the case cover 2B side of the idler shaft 123 is fitted into the support hole 2e of the case cover 2B, whereby the idler shaft 123 is connected to the case cover. It is attached so as to have a cantilever structure with respect to 2B.

Even in this in-wheel motor drive device 1 ₂ configured as described above, the reduction gear mechanism 20 is disposed on the third axis AX3 parallel to the first axis AX1 and the second axis AX2, the small-diameter gear 21 The large-diameter gear 25a meshes with the large-diameter gear 25a, so that the reduction gear mechanism 20 can set a sufficient reduction ratio. The diameter can be reduced, and the reduction gear mechanism 20 can be reduced in size. Accordingly, downsizing of the in-wheel motor drive device 1 _2, it is possible to prevent interfering with the suspension device and the brake device.

  Further, the third axis AX3 is arranged on a straight line X passing through the first axis AX1 and the second axis AX2, that is, the small diameter gear 21, the idler gear 22, and the large diameter gear 25a are arranged linearly. Since the thrust force received from the small-diameter gear 21 with respect to 22 and the thrust force received from the large-diameter gear 25a with respect to the idler gear 22 are generated at the positions opposite to the circumferential direction in the idler gear 22, these thrust forces act in the twisting direction. You can cancel each other without having to. Thereby, the support structure of the idler gear 22 (that is, the idler shaft 123) can be simplified, and the support structure of the idler gear 22 can be downsized.

  Further, the end portion 123d of the case cover 2B side of the idler shaft 123 that rotatably supports the idler gear 22 is supported by the support hole 2e of the case 2, so that the motor 3 is arranged on the opposite side in the axial direction. It can be possible to place it at a location.

Also in the present embodiment, the reduction planetary gear 40 and the motor 3 are arranged at positions that overlap in the axial direction when viewed from the radial direction, so that the motor 3 does not protrude toward the vehicle side, and the in-wheel motor drive it is possible to shorten the device 1 ₂ in the axial direction. Further, since the small-diameter gear 21, the large-diameter gear 25a, and the idler gear 22 of the reduction gear mechanism 20 are also arranged at positions overlapping each other in the axial direction when viewed from the radial direction, the reduction gear mechanism 20 may swell in the axial direction. no, it is possible to shorten the in-wheel motor drive device 1 ₂ in the axial direction.

The above-described in-wheel motor drive device 1 of the _first and second _embodiments, the 1 ₂ those disposed motor 3 (the first axis AX1) upward side of the second axis AX2 As described above, depending on the position of the caliper of the brake device, the mounting position of the suspension device, etc., the motor 3 (first axis AX1) may be disposed below the second axis AX2, that is, the motor 3 is the brake device. It is a preferable form that it is arranged so as not to interfere with the suspension device.

  In the first and second embodiments, the speed reduction planetary gear 40 is described as an example of the speed reduction mechanism, but any speed reduction mechanism may be used. As the speed reduction mechanism, for example, a cycloid speed reducer (Japanese Patent Laid-Open No. 2009-58005), a roller speed reducer (Japanese Patent Laid-Open No. 2006-103521), and the like are conceivable.

The in-wheel motor drive devices 1 ₁ and 1 _{2 according to} the first and second embodiments are basically mounted on the right wheel with respect to the vehicle traveling direction. The in-wheel motor drive devices 1 ₁ and 1 ₂ that are to be mounted respectively on the left wheel are reverse in the front-rear direction (the shape shown on the mirror surface) in FIGS. .

DESCRIPTION OF SYMBOLS 1 In-wheel motor drive device 2 Case member 2d Groove part 2e Support part (support hole)
3 Rotating electric machine (motor)
4 Stator 5 Rotor 20 Transmission Mechanism 21 First Gear (Small Diameter Gear)
22 3rd gear (idler gear)
23 Shaft member (idler shaft)
23a Axial hole 23b Radial hole 23c End 23e on the other side in the axial direction Projection 24 Plate member 24a Opposing part 24b Recess 25a Second gear (large diameter gear)
40 Reduction mechanism (reduction planetary gear)
50 Output shaft 123 Shaft member (idler shaft)
123d End AX1 on the other side in the axial direction AX1 First axis AX2 Second axis AX3 Third axis X Straight line b3 Bearing (needle bearing)

Claims (7)

In an in-wheel motor drive device attached to the inside of a wheel of a wheel and capable of driving the wheel,
A rotating electrical machine disposed on the first axis;
A transmission mechanism for decelerating and transmitting the rotation of the rotating electrical machine from the first axis to a second axis parallel to the first axis;
A speed reduction mechanism disposed on the second shaft and configured to decelerate the rotation transmitted by the transmission mechanism;
An output shaft disposed on the second shaft and outputting the reduced speed rotation of the speed reduction mechanism to the wheel;
The transmission mechanism is
A first gear disposed on the first shaft and drivingly connected to the rotating electrical machine;
A second gear disposed on the second shaft, connected to the speed reduction mechanism, and having a larger diameter than the first gear;
A third gear disposed on a third axis parallel to the first axis and the second axis, and meshing with the first gear and the second gear;
An in-wheel motor drive device characterized by that. The third axis is disposed on a straight line passing through the first axis and the second axis.
The in-wheel motor drive device according to claim 1. A case member that houses the rotating electrical machine, the transmission mechanism, the speed reduction mechanism, and a part of the output shaft;
A shaft member that passes through the center of the third gear and rotatably supports the third gear,
In the shaft member, the rotating electrical machine is disposed on one side in the axial direction, and an end portion on the other side in the axial direction is supported by a support portion of the case member.
The in-wheel motor drive device according to claim 1 or 2. A plate member that is supported by the case member and has a facing portion that faces the supporting portion of the case member,
The shaft member is supported on the opposite side of the plate member on one side in the axial direction.
The in-wheel motor drive device according to claim 3. The rotating electrical machine has a stator and a rotor,
The opposing portion of the plate member has a concave portion that is recessed in the axial direction opposite to the stator in a portion that overlaps the stator when viewed in the axial direction.
The in-wheel motor drive device of Claim 4 characterized by the above-mentioned. The case member has a groove portion that is formed in a groove shape and guides lubricating oil;
The shaft member is formed so as to penetrate in the axial direction, and an axial hole through which lubricating oil is introduced from the groove, and a bearing that is formed to penetrate from the axial hole toward the outer peripheral side and rotatably supports the third gear. A radial hole that guides the lubricating oil, and a protrusion inserted into the groove of the case member,
The in-wheel motor drive device according to claim 4, wherein the in-wheel motor drive device is provided. The speed reduction mechanism and the rotating electrical machine are arranged at positions overlapping in the axial direction when viewed from the radial direction,
The first gear, the second gear, and the third gear of the transmission mechanism are arranged at positions that overlap each other in the axial direction when viewed from the radial direction.
The in-wheel motor drive device according to any one of claims 1 to 6.

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