WO2019163884A1 - In-wheel motor drive device - Google Patents

Abstract

A speed reduction section of this in-wheel motor drive device includes: an output shaft (38) which is joined to the rotating ring (12) of a wheel hub bearing section (11); an output gear (37) which is a helical gear provided coaxially with the output shaft; an intermediate gear (36) which is a helical gear meshing with the output gear; and a rolling bearing (38a) which is positioned further toward one axial side than the output gear and which rotatably supports the output shaft. An axial load (Fa) acting on the meshing portion (71) of the output gear while a wheel is being driven acts in a direction toward the one axial side, and at least some of the rolling bodies (73) of the rolling bearing (38a) are arranged in a region (72) extending in a direction in which the resultant (R) of the axial load (Fa), which acts from one axial end to the other axial end of the meshing section (71) of the output gear, and a radial load (Fr) acts.

Description

In-wheel motor drive device

The present invention relates to an in-wheel motor drive device including a gear-type reduction gear portion having a plurality of gears, and more particularly to an in-wheel motor drive device in which a final gear (output gear) of the reduction gear portion is a helical gear. .

The in-wheel motor drive device disposed inside the wheel includes a motor unit that drives the wheel, a wheel hub bearing unit to which the wheel is attached, and a deceleration unit that decelerates the rotation of the motor unit and transmits the rotation to the wheel hub bearing unit. Is provided. Conventionally, a parallel shaft gear reduction mechanism having a plurality of gears has been adopted as a reduction mechanism in the reduction unit.

Japanese Patent Application Laid-Open No. 2017-165392 (Patent Document 1) discloses that an in-wheel motor drive device has a speed reduction unit including an input shaft coupled to a motor rotation shaft of the motor unit, an input gear coupled to the input shaft, and a wheel hub bearing unit. An output shaft coupled to the rotating wheel, an output gear (final gear) provided on the output shaft, an intermediate shaft extending in parallel with the input shaft and the output shaft, an intermediate gear provided on the intermediate shaft, and both ends of the output shaft, A configuration in which each of the first bearing and the second bearing is rotatably supported is disclosed. Patent Document 1 also discloses that the tooth contact is improved by using a helical gear as the reduction gear.

JP 2017-165392 A

According to the output shaft support structure disclosed in Patent Document 1, since the output shaft can be stably supported at both ends by the first bearing and the second bearing, the rotating wheel of the wheel hub bearing portion from the wheel wheel. Even if an external force is applied to the motor, the effect of suppressing the displacement of the output shaft and preventing the uneven wear of the gears of the speed reduction portion can be obtained. Moreover, in patent document 1, since the helical gear is applied as a gear of a reduction part, high silence is anticipated.

However, the helical gear has a characteristic that an axial load (axial force) is generated in the meshing portion according to the twist direction (twist angle) of the tooth stripe. Therefore, when a helical gear is applied to the output gear provided on the output shaft, the output gear itself may be tilted due to the influence of the axial load applied to the meshing portion with the intermediate gear. Therefore, in order to realize high silence, a technique for suppressing the inclination of the output gear is desired.

The present invention has been made in order to solve the above-described problems, and its object is to provide an inclination of the output gear itself when a helical gear is applied to the output gear as the final gear of the speed reduction unit. It is providing the in-wheel motor drive device which can suppress this.

An in-wheel motor drive device according to an aspect of the present invention includes a wheel hub bearing portion having a rotating wheel to which a wheel is attached, and a speed reduction portion. The speed reducer includes an output shaft coupled to the rotating wheel of the wheel hub bearing portion, an output gear that is a helical gear provided coaxially with the output shaft, an intermediate shaft provided in parallel with the output shaft, An intermediate gear that is a helical gear that is provided coaxially with the shaft and meshes with the output gear, and a rolling bearing that is disposed on one side in the axial direction of the output gear and rotatably supports the output shaft. The direction of the axial load generated in the meshing portion of the output gear when the wheel is driven is one side in the axial direction, and at least part of the rolling elements of the rolling bearing is from the one end in the axial direction of the meshing portion of the output gear to the other. It arrange | positions in the area | region of the direction where the resultant force of the axial load applied to an end and radial load goes.

The output gear has a torsion angle β and a pressure angle α. The region in the direction of the resultant force is a first straight line extending from one end in the axial direction of the meshing portion of the output gear at an inclination angle of θ relative to the radial direction, and a radial from the other end in the axial direction of the meshing portion of the output gear. It is a region sandwiched between the second straight lines extending at an inclination angle of θ with respect to the direction, and the angle θ is expressed by the following equation.
Angle θ = atan {tan β / (tan α / cos β)}

Preferably, the in-wheel motor drive device further includes a casing that houses the speed reduction portion, and the rolling bearing is disposed between the outer diameter surface of the output shaft and a cylindrical surface formed in the casing.

The annular protrusion may be provided on one end face in the axial direction of the output gear, and the rolling bearing may be accommodated between the annular protrusion and the cylindrical surface of the casing.

Preferably, the speed reducer further includes a rolling bearing disposed on the other side in the axial direction from the output gear and rotatably supporting the output shaft.

Preferably, one side in the axial direction is the outer side in the vehicle width direction, and the other side in the axial direction is the inner side in the vehicle width direction.

According to the present invention, at least a part of the rolling elements of the rolling bearing that supports the output shaft rotates between the axial load and the radial load applied from one end to the other end in the axial direction of the meshing portion of the output gear when the wheel is driven. Since it is arranged in the region in the direction of the resultant force, the inclination of the output gear itself can be suppressed.

It is the longitudinal cross-sectional view which cut | disconnects and expand | deploys the in-wheel motor drive device which concerns on embodiment of this invention at a predetermined plane. It is a cross-sectional view which shows typically the internal structure of the deceleration part of the in-wheel motor drive device which concerns on embodiment of this invention. It is a perspective view which shows the state which looked at the output gear in embodiment of this invention from diagonally upward. It is a perspective view showing typically the meshing state of an output gear and an intermediate gear in an embodiment of the invention. In an embodiment of the present invention, it is a figure showing a rotation direction of an output gear and an intermediate gear at the time of forward rotation driving and reverse rotation driving, respectively. In an embodiment of the present invention, it is a figure which shows notionally an axial load which arises in an output gear at the time of wheel drive (at the time of forward rotation drive). In embodiment of this invention, it is a figure which shows notionally the radial load which arises in an output gear at the time of wheel drive (at the time of forward rotation drive). In embodiment of this invention, it is a figure which shows notionally the direction of the resultant force of the axial load and radial load which are applied to the meshing part of an output gear at the time of wheel drive (at the time of forward rotation drive). In embodiment of this invention, it is a figure which shows notionally the arrangement | positioning range of the rolling bearing which carries out rotation support of the output gearwheel. In an embodiment of the present invention, it is a figure showing notionally the direction of tangential force and axial load which arise in a meshing part of an output gear at the time of reverse rotation drive. In an embodiment of the present invention, it is a figure which shows notionally the direction of tangential force and radial load which arise in a meshing part of an output gear at the time of reverse rotation drive. It is a graph which shows an example of the relationship between the twist angle (alpha) and resultant force angle (theta) when the pressure angle (alpha) of an output gear is made constant. It is a figure which shows the comparative example of embodiment of this invention. It is a figure which shows the detailed structural example of the deceleration part in embodiment of this invention, and is a longitudinal cross-sectional view which cut | disconnects and expand | deploys an in-wheel motor drive device by a predetermined plane. It is a figure which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the outboard side. It is a perspective view which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the outboard side and the vehicle rear side. It is a perspective view which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the outboard side and the vehicle front side. It is a figure which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the inboard side. It is a perspective view which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the inboard side and the vehicle rear side. It is a perspective view which represents typically the state which looked at the internal structure of the deceleration part shown in FIG. 14 from the inboard side and the vehicle rear side. It is the schematic diagram which looked at the gear assembly of the reduction part shown in FIG. 14 from the outboard side. It is the schematic diagram which looked at the gear assembly of the reduction part shown in FIG. 14 from the inboard side. It is the typical which looked at the gear assembly of the reduction part shown in FIG. 14 from the vehicle rear side. It is the typical which looked at the gear assembly of the reduction part shown in FIG. 14 from the vehicle front side. It is the typical which looked at the gear assembly of the reduction part shown in FIG. 14 from the vehicle upper direction. It is the typical which looked at the gear assembly of the reduction part shown in FIG. 14 from the vehicle downward direction. It is the perspective view which looked at the gear assembly of the reduction part shown in FIG. 14 from the outboard side and the vehicle front side. It is the perspective view which looked at the gear assembly of the deceleration part shown in FIG. 14 from the inboard side and the vehicle front side. It is an expanded sectional view which expands and shows some deceleration parts shown in FIG. It is an expanded sectional view which expands and shows a part of deceleration part shown in FIG. (A), (B) is a figure which shows typically the position of the oil level at the time of vehicle stationary and acceleration. It is a figure which represents typically the state which looked at the in-wheel motor drive device shown in FIG. 14, and its peripheral structure from the vehicle rear.

Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Basic configuration example>
First, a basic configuration example of the in-wheel motor drive device 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. The in-wheel motor drive device 1 is mounted on a passenger car such as an electric vehicle and a hybrid vehicle.

FIG. 1 is a longitudinal sectional view showing an in-wheel motor drive device 1 according to an embodiment of the present invention cut along a predetermined plane and developed. FIG. 2 is a cross-sectional view showing the internal structure of the speed reduction unit 31 of the in-wheel motor drive device 1, and schematically shows a state viewed from the outside in the vehicle width direction. The predetermined plane shown in FIG. 1 is a developed plane obtained by connecting the plane including the axis M and the axis N shown in FIG. 2 and the plane including the axis N and the axis O in this order. In FIG. 1, the left side of the drawing represents the vehicle width direction outside (outboard side), and the right side of the drawing represents the vehicle width direction inside (inboard side). In FIG. 2, each gear inside the speed reduction unit 31 is represented by a tip circle, and individual teeth are omitted.

The in-wheel motor drive device 1 includes a wheel hub bearing unit 11 provided at the center of the wheel W, a motor unit 21 that drives the wheel, and a deceleration that decelerates the rotation of the motor unit 21 and transmits it to the wheel hub bearing unit 11. Part 31.

The motor part 21 and the speed reduction part 31 are arranged offset from the axis O of the wheel hub bearing part 11. The axis O extends in the vehicle width direction and coincides with the axle. In the present embodiment, it is assumed that one side in the axis O direction is the outboard side and the other side in the axis O direction is the inboard side.

Regarding the position in the axis O direction, the wheel hub bearing portion 11 is disposed on one side in the axial direction of the in-wheel motor drive device 1, the motor portion 21 is disposed on the other side in the axial direction of the in-wheel motor drive device 1, and the speed reduction portion 31 is disposed on the motor portion. The axial position of the speed reduction part 31 overlaps with the axial direction position of the wheel hub bearing part 11.

The in-wheel motor drive device 1 is a vehicle motor drive device that drives wheels of an electric vehicle. The in-wheel motor drive device 1 is connected to a vehicle body (not shown). The in-wheel motor drive device 1 can drive an electric vehicle at a speed of 0 to 180 km / h.

The wheel hub bearing portion 11 is a rotating inner ring / fixed outer ring, and includes an inner ring 12 as a rotating wheel (hub wheel) coupled to the wheel wheel W, and an outer ring as a fixed ring disposed coaxially on the outer diameter side of the inner ring 12. 13 and a plurality of rolling elements 14 arranged in an annular space between the inner ring 12 and the outer ring 13. The center of rotation of the inner ring 12 coincides with an axis O passing through the center of the wheel hub bearing portion 11.

The outer ring 13 penetrates the front portion 39f of the main body casing 39 and is connected and fixed to the front portion 39f. The front portion 39 f is a casing wall portion that covers one end of the speed reduction portion 31 in the axis O direction of the main body casing 39. For example, a plurality of outer ring protrusions protruding in the outer diameter direction are provided on the outer peripheral surface of the outer ring 13 at different positions in the circumferential direction, and one side of the axis O direction with respect to the through hole provided in each outer ring protrusion The bolt is passed through. The shaft portion of each bolt is screwed into a female screw hole formed in the front portion 39 f of the main body casing 39.

The carrier member 61 is connected and fixed to the outer ring 13. On the outer peripheral surface of the outer ring 13, a plurality of outer ring protruding portions 13g protruding in the outer diameter direction are provided at different positions in the circumferential direction. The carrier member 61 is located on the other side of the outer ring protruding portion 13g in the axis O direction, and a bolt 62 is passed from one side of the axis O direction to the through hole of the outer ring protruding portion 13g and the female screw hole of the carrier member 61. The carrier member 61 is fixed to the main body casing 39 by a bolt 63 passed from the other side in the axis O direction.

The inner ring 12 is a cylindrical body longer than the outer ring 13 and is passed through the center hole of the outer ring 13. A coupling portion 12f is formed at one end of the inner ring 12 protruding from the outer ring 13 to the outside (outboard side) in the axis O direction. The coupling portion 12f is a flange and constitutes a coupling portion for coupling coaxially with the brake rotor BD and the wheel. The inner ring 12 is coupled to the wheel W at the coupling portion 12f and rotates integrally with the wheel.

In the annular space between the inner ring 12 and the outer ring 13, a plurality of rows of rolling elements 14 are arranged. The outer peripheral surface of the central portion of the inner ring 12 in the direction of the axis O constitutes the inner raceway surface of the plurality of rolling elements 14 arranged in the first row. An inner race 12r is fitted to the outer periphery of the other end of the inner ring 12 in the axis O direction. The outer peripheral surface of the inner race 12r constitutes the inner race of the plurality of rolling elements 14 arranged in the second row. The inner peripheral surface at one end of the outer ring 13 in the direction of the axis O constitutes the outer raceway surface of the rolling elements 14 in the first row. An inner peripheral surface of the other end portion of the outer ring 13 in the axis O direction forms an outer raceway surface of the rolling elements 14 in the second row. A sealing material 16 is further interposed in the annular space between the inner ring 12 and the outer ring 13. The sealing material 16 seals both ends of the annular space to prevent intrusion of dust and foreign matter. The output shaft 38 of the speed reduction part 31 is inserted into the center hole at the other end in the axis O direction of the inner ring 12 and is spline-fitted.

The motor unit 21 has a motor rotating shaft 22, a rotor 23, and a stator 24, and is sequentially arranged from the axis M of the motor unit 21 to the outer diameter side in this order. The motor unit 21 is an inner rotor / outer stator type radial gap motor, but may be of other types. For example, although not shown, the motor unit 21 may be an axial gap motor.

The motor unit 21 is accommodated in a motor casing 29. The motor casing 29 surrounds the outer periphery of the stator 24. One end of the motor casing 29 in the direction of the axis M is coupled to the back surface portion 39 b of the main body casing 39. The other end of the motor casing 29 in the axis M direction is sealed with a plate-like motor casing cover 29v. The back surface portion 39 b is a casing wall portion that covers the other end of the main body casing 39 in the direction of the axis M (axis O direction) of the speed reduction portion 31.

The main body casing 39, the motor casing 29, and the motor casing cover (rear cover) 29 v constitute the casing 10 that forms the outline of the in-wheel motor driving device 1.

The stator 24 includes a cylindrical stator core 25 and a coil 26 wound around the stator core 25. The stator core 25 is formed by laminating ring-shaped steel plates in the axis M direction.

Both end portions of the motor rotating shaft 22 are rotatably supported by the back portion 39b of the main body casing 39 and the motor casing cover 29v via rolling bearings 27 and 28. An axis M serving as the rotation center of the motor rotation shaft 22 and the rotor 23 extends in parallel with the axis O of the wheel hub bearing portion 11. That is, the motor unit 21 is disposed offset from the axis O of the wheel hub bearing unit 11. For example, as shown in FIG. 2, the axis M of the motor unit 21 is offset from the axis O in the vehicle front-rear direction, and specifically, is disposed in front of the vehicle relative to the axis O.

The speed reduction unit 31 includes an input shaft 32 that is coaxially coupled to the motor rotation shaft 22 of the motor unit 21, an input gear 33 that is provided coaxially on the outer peripheral surface of the input shaft 32, a plurality of intermediate gears 34 and 36, An intermediate shaft 35 coupled to the center of the gears 34, 36, an output shaft 38 coupled coaxially to the inner ring 12 of the wheel hub bearing portion 11, and an output gear 37 provided coaxially on the outer peripheral surface of the output shaft 38. The plurality of gears and the rotation shaft of the speed reduction unit 31 are accommodated in the main body casing 39. The main body casing 39 is also referred to as a speed reduction part casing because it forms an outline of the speed reduction part 31.

The input gear 33 is a helical gear with external teeth. The input shaft 32 has a hollow structure, and one end in the axial direction of the motor rotation shaft 22 is inserted into the hollow portion 32 h of the input shaft 32. Thereby, the motor rotating shaft 22 is spline-fitted (or serrated fitted) to the input shaft 32 so as not to be relatively rotatable. The input shaft 32 is rotatably supported by the front portion 39f and the back portion 39b of the main body casing 39 via rolling bearings 32a and 32b on both ends of the input gear 33.

The axis N that is the center of rotation of the intermediate shaft 35 of the speed reduction part 31 extends parallel to the axis O. Both ends of the intermediate shaft 35 are rotatably supported by the front portion 39f and the back portion 39b of the main body casing 39 via bearings 35a and 35b. A first intermediate gear 34 and a second intermediate gear 36 are provided coaxially with the axis N of the intermediate shaft 35 at the center of the intermediate shaft 35. The first intermediate gear 34 and the second intermediate gear 36 are external helical gears, and the diameter of the first intermediate gear 34 is larger than the diameter of the second intermediate gear 36. The large-diameter first intermediate gear 34 is disposed on the other side in the axis N direction with respect to the second intermediate gear 36, and meshes with the small-diameter input gear 33. The small-diameter second intermediate gear 36 is disposed on one side in the axis N direction relative to the first intermediate gear 34 and meshes with the large-diameter output gear 37.

The axis N of the intermediate shaft 35 is disposed above the axis O and the axis M as shown in FIG. In addition, the axis N of the intermediate shaft 35 is arranged in front of the vehicle with respect to the axis O and behind the vehicle with respect to the axis M. The speed reduction unit 31 is a three-axis parallel shaft gear reducer having axes O, N, and M that are arranged at intervals in the vehicle front-rear direction and extend parallel to each other.

The output gear 37 is a helical gear with external teeth, and is provided coaxially at the center of the output shaft 38. The output shaft 38 extends along the axis O. One end of the output shaft 38 in the direction of the axis O is inserted into the center hole of the inner ring 12 and is fitted so as not to be relatively rotatable. Such fitting is spline fitting or serration fitting. A central portion (one end side) of the output shaft 38 in the axis O direction is rotatably supported by the front portion 39f of the main body casing 39 via the rolling bearing 38a. The other end portion (the other end side) in the axis O direction of the output shaft 38 is rotatably supported by the back surface portion 39b of the main body casing 39 via the rolling bearing 38b.

The rolling bearing 38 a is positioned on the outboard side with respect to the output gear 37, and the rolling bearing 38 b is positioned on the inboard side with respect to the output gear 37. Each of the rolling bearings 38 a and 38 b is disposed between the outer diameter surface of the output shaft 38 and the cylindrical surface formed in the main body casing 39. Specifically, the outer ring of the rolling bearing 38a is fixed to the cylindrical surface formed on the front portion 39f of the main body casing 39, and the outer ring of the rolling bearing 38b is fixed to the cylindrical surface formed on the rear surface portion 39b of the main body casing 39. It is fixed.

The reduction gear 31 is configured to engage the input shaft 32 by meshing the small-diameter drive gear and the large-diameter driven gear, that is, meshing the input gear 33 and the first intermediate gear 34, and meshing the second intermediate gear 36 and the output gear 37. The rotation is decelerated and transmitted to the output shaft 38. The rotating elements from the input shaft 32 to the output shaft 38 of the speed reduction unit 31 constitute a drive transmission path for transmitting the rotation of the motor unit 21 to the inner ring 12. The input shaft 32, the intermediate shaft 35, and the output shaft 38 are supported at both ends by the rolling bearing described above. These rolling bearings 32a, 35a, 38a, 32b, 35b, and 38b are radial bearings.

The main body casing 39 includes a cylindrical part, and a plate-like front part 39f and a rear part 39b covering both ends of the cylindrical part. The cylindrical portion covers the internal parts of the speed reducing portion 31 so as to surround the axes O, N, and M extending in parallel with each other. The plate-shaped front portion 39f covers the internal parts of the speed reduction portion 31 from one side in the axial direction. The plate-like back surface portion 39b covers the internal parts of the speed reducing portion 31 from the other side in the axial direction. As shown in FIG. 2, an oil tank 40 in which lubricating oil is stored is provided at the lower part of the main body casing 39.

The back surface portion 39 b of the main body casing 39 is a partition wall that is coupled to the motor casing 29 and partitions the internal space of the speed reduction portion 31 and the internal space of the motor portion 21. The motor casing 29 is supported by the main body casing 39 and protrudes from the main body casing 39 to the other side in the axial direction.

When electric power is supplied to the stator 24 of the motor unit 21 from the outside of the in-wheel motor drive device 1, the rotor 23 of the motor unit 21 rotates and outputs rotation from the motor rotation shaft 22 to the speed reduction unit 31. The deceleration unit 31 decelerates the rotation input from the motor unit 21 to the input shaft 32 and outputs the rotation from the output shaft 38 to the wheel hub bearing unit 11. The inner ring 12 of the wheel hub bearing portion 11 rotates at the same rotational speed as the output shaft 38 and drives a wheel (not shown) attached and fixed to the inner ring 12.

<About the rotation support structure of the output shaft>
Next, the rotation support structure of the output shaft 38 of the in-wheel motor drive device 1 according to the present embodiment will be described.

As described above, the output shaft 38 is supported at both ends by the two rolling bearings 38a and 38b having different axial positions. Accordingly, since the output shaft 38 is stably rotated and supported, even if the inner ring 12 of the wheel hub bearing portion 11 coupled to the output shaft 38 is slightly displaced (deformed) by an external force accompanying a turning load, the output shaft 38 The displacement (tilt) of 38 can be suppressed as much as possible.

Here, in the present embodiment, as shown in FIGS. 3 and 4, a helical gear is applied as the output gear 37 provided coaxially with the output shaft 38. FIG. 3 shows a state where the output gear 37 is viewed obliquely from above, and FIG. 4 schematically shows a meshed state of the output gear 37 and the intermediate gear 36.

A helical gear is a cylindrical gear in which tooth stripes are formed in a helical line shape. Therefore, the output gear 37 has a twist angle β and a pressure angle α. The pressure angle α corresponds to an angle formed by a radius line and a tangent to the tooth profile at one point (typically a pitch point) of the tooth surface. As described above, when the output gear 37 and the intermediate gear 36 are helical gears, the tooth contact at the gear meshing portion is improved, so that (ideally) high silence can be obtained.

On the other hand, an axial load peculiar to the helical gear is generated at the meshing portion of the output gear 37 (meshing portion with the intermediate gear 36) when the vehicle is running, that is, when the wheel is driven. Therefore, the output gear 37 may be inclined due to the influence of the axial load acting on the meshing portion of the output gear 37.

This will be described with reference to FIGS. FIG. 5 is a diagram illustrating the rotation directions of the output gear 37 and the intermediate gear 36 during forward rotation driving and reverse rotation driving, respectively. FIG. 6 is a diagram conceptually showing the axial load generated in the output gear 37 when the wheel is driven. FIG. 7 is a diagram conceptually showing the radial load generated in the output gear 37 when the wheels are driven. FIG. 8 is a diagram conceptually showing the direction of the resultant force between the axial load and the radial load. 5 and 7 show a state where the gears 36 and 37 are viewed from the outboard side, and FIG. 6 shows a state where the gears 36 and 37 shown in FIG. 5 are viewed from above. ing. FIG. 8 is an enlarged view of a part of the longitudinal sectional view of FIG.

6 to 8, the radial load Fr and the axial load Fa are generated in the meshing portion 71 of the output gear 37. Therefore, the load applied to the meshing portion 71 of the output gear 37 is expressed as a resultant force R of the axial load Fa and the radial load Fr. The direction in which the resultant force R is directed is the same direction from one end to the other end in the axial direction of the meshing portion 71 of the output gear 37. As shown in FIG. 8, the inclination angle θ of the resultant force R with respect to the radial direction on the cutting plane passing through the axes O and N and parallel to the axes O and N is determined by the ratio between the axial load Fa and the radial load Fr. .

As shown in FIG. 6, the axial load Fa is obtained from the tangential force Ft and the twist angle β of the output gear 37. That is, the axial load Fa is expressed by the following formula (1). In FIG. 6, the direction of the circumferential load is indicated by an arrow f.
Fa = Ft × tan β (1)

As shown in FIG. 7, the radial load Fr is obtained from the tangential force Ft and the pressure angle α of the output gear 37. That is, the radial load Fr is expressed by the following equation (2). In FIG. 7, a common normal line between the tooth surface of the output gear 37 and the tooth surface of the intermediate gear 36 is indicated by a two-dot chain line.
Fr = Ft × (tan α / cos β) (2)

Therefore, the inclination angle (hereinafter also referred to as “the resultant angle”) θ of the resultant force R with respect to the radial direction is expressed by the following equation (3).
θ = atan {tan β / (tan α / cos β)} (3)

In the present embodiment, the pressure angle α of the output gear 37 is, for example, 20 degrees. In this case, if the twist angle β of the output gear 37 is, for example, 30 degrees, the resultant force angle θ is 56.3 degrees. The relationship between the torsion angle α and the resultant force angle θ when the pressure angle α is 20 degrees as an example is shown in the graph of FIG.

The twisting direction of the tooth stripe of the output gear 37 in this embodiment is a so-called right-handed twisting direction, and the tooth tip 37a of the output gear 37 is out on the inboard side (the other side in the axial direction) as shown in FIG. It inclines so that it may become a vehicle front rather than the board side (one axial direction side). Therefore, in the present embodiment, the direction of the axial load Fa generated in the meshing portion of the output gear 37 during the forward rotation drive is on the outboard side as shown in FIG. In this case, the resultant force R acts on the meshing portion 71 of the output gear 37 during forward rotation in a direction inclined by an angle θ toward the outboard side with respect to the radial direction. The direction of the tangential force Ft during forward rotation is on the vehicle front side.

As shown in FIGS. 10 and 11, during reverse rotation driving, the direction of the tangential force Ft is reverse (rear side of the vehicle), so that the axial load Fa generated in the meshing portion 71 of the output gear 37 during reverse rotation driving. The direction is on the inboard side.

In this way, when the output gear 37 is a helical gear, the resultant portion R has a resultant force R in a direction inclined by an angle θ with respect to the radial direction, as shown in FIG. Works. Thereby, since a bending moment is applied to the output gear 37, the output gear 37 may be inclined.

Therefore, in this embodiment, the bending moment applied to the output gear 37 is reduced by adjusting the arrangement position of at least one of the two rolling bearings 38a and 38b that rotatably support the output shaft 38.

<About the position of the rolling bearing>
As described above, the axial load Fa that faces the outboard side during forward rotation is applied to the meshing portion 71 of the output gear 37. For this reason, in the present embodiment, the arrangement position of the rolling bearing 38 a located on the outboard side with respect to the output gear 37 is adjusted.

Specifically, in the present embodiment, the rolling bearing 38 a is disposed within a range that receives the resultant force R applied to the meshing portion 71 of the output gear 37. Thereby, it becomes possible to support the load including the axial component (the resultant force R) by the rolling bearing 38a.

The range in which the rolling bearing receives (can receive) the resultant force R corresponds to a region in the direction in which the resultant force R of the axial load Fa and the radial load Fr applied from one end to the other end of the meshing portion 71 of the output gear 37 is directed. To do. FIG. 9 conceptually shows a region 72 in the direction in which the resultant force R is directed. That is, the rolling bearing 38 a is disposed in a region 72 in a direction in which a resultant force R of the axial load Fa and the radial load Fr applied from one end to the other end in the axial direction of the meshing portion 71 of the output gear 37 is directed.

The region 72 includes a first straight line L1 extending from the one end 71a of the meshing portion 71 of the output gear 37 at an inclination angle θ with respect to the radial direction, and an axis O direction of the meshing portion 71 of the output gear 37. It is sandwiched between a second straight line L2 extending from the other end 71b at an inclination angle of θ relative to the radial direction. In FIG. 9, a dot is added to the region 72 for easy understanding.

In this embodiment, the rolling element 73 of the rolling bearing 38a is disposed in the region 72. The width of the region 72 in the axis O direction corresponds to the tooth width of the output gear 37. Therefore, when viewed in the load direction (direction of the resultant force R) received by the output gear 37 from the intermediate gear 36, the meshing portion 71 of the output gear 37 and the rolling element 73 of the rolling bearing 38a overlap.

In the present embodiment, for example, as shown in FIG. 8, the rolling bearing 38 a includes an outer peripheral surface of an annular convex portion 37 b erected on one end surface in the axis O direction of the output gear 37, and a front portion 39 f of the main body casing 39. It is arrange | positioned between the cylindrical surfaces formed in this. The cylindrical surface of the front portion 39f is configured by an inner peripheral surface of an annular convex portion 39i that is erected on the inner wall surface of the front portion 39f. As described above, the rolling bearing 38a may be arranged so as to support the output shaft 38 in a rotational manner, and may not be configured to directly support the outer peripheral surface of the output shaft 38. In the case of this embodiment, the inner end 12 of the wheel hub bearing 11 and the other end in the axis O direction of the outer ring 13 may be accommodated in the space on the inner diameter side of the annular convex portion 37b of the output gear 37.

A comparative example is shown in FIG. In the comparative example, the region 72 sandwiched between the first straight line L1 and the second straight line L2 does not include the rolling element 173 of the rolling bearing 138a on the outboard side, and is shifted to the inboard side from the region 72. A rolling element 173 is arranged at the (offset) position. That is, the rolling elements 173 of the rolling bearing 138a are not disposed in the region 72 in the direction in which the resultant force R is directed. The rolling bearing 138 a is disposed in an annular recess formed on one end surface of the output gear 37 in the axis O direction.

The distance D shown in FIG. 13 is the shortest distance between the second straight line L2 and the straight line L3 that are parallel to each other, and corresponds to an offset amount from the region 72. The straight line L3 is a tangent on the inboard side of the rolling element 173, and when the second straight line is at the position of the straight line L3, the rolling element 173 is disposed in the region 72 in the direction in which the resultant force R is directed. .

On the other hand, in the present embodiment, the rolling element 73 of the rolling bearing 38a is included in the region in the direction of the resultant force R, that is, the region 72 sandwiched between the first straight line L1 and the second straight line L2. The torsion angle β and pressure angle α of the output gear 37 and the relative position of the rolling element 73 with respect to the meshing surface of the output gear 37 in the load direction (the direction of the resultant force R) are determined. In this case, since the offset amount (moment arm length) between the gear load (the resultant force R) and the bearing support is shorter than that in the comparative example, the bending moment generated in the output gear 37 can be reduced. Therefore, according to the present embodiment, elastic deformation of the output gear 37 can be suppressed.

As described above, the rolling element 73 of the rolling bearing 38a on the outboard side is a region in the direction in which the resultant force R of the axial load Fa and the radial load Fr applied to the meshing portion 71 of the output gear 37 is directed during normal rotation driving. By disposing in 72, the inclination of the output gear 37 during forward rotation driving can be suppressed.

The forward drive is overwhelmingly more frequently used than the reverse drive. Therefore, by suppressing the inclination of the output gear 37 during the forward drive, the vibration of the gear meshing part during the traveling of the vehicle can be suppressed. It is possible to prevent or suppress the generation of noise associated with.

Further, since the inclination of the output gear 37 is suppressed, wear of the tooth surface of the output gear 37 can be effectively prevented or suppressed. As a result, the durability of the tooth surface of the output gear 37 can be improved. Moreover, since the moment load of the output gear 37 can be suppressed, the output gear 37 can be reduced in weight.

Furthermore, since the rotation support of the output shaft 38 and the inclination suppression of the output gear 37 are realized by the common rolling bearing 38a, the increase in the number of parts and the weight can be avoided.

As shown in FIG. 9, although it is desirable that the entire rolling element 73 that is the target of the rolling bearing 38a is included in the region 72 in the direction in which the resultant force R is directed, the rolling element 74 indicated by an imaginary line in FIG. , 75, only a part of the rolling elements may be included in the region 72 in the direction in which the resultant force R is directed. That is, it is only necessary that at least a part of the rolling elements of the rolling bearing 38a is disposed in the region 72 in the direction in which the resultant force R is directed.

(Modification)
In the above embodiment, the tooth lines of the output gear 37 are twisted in the right direction, but the tooth lines of the output gear may be twisted in the left direction. That is, the tooth tip of the output gear may be inclined so that the outboard side (one side in the axial direction) is ahead of the vehicle than the inboard side (the other side in the axial direction). In this case, since the direction of the axial load generated in the meshing portion of the output gear during forward rotation is on the inboard side, contrary to the above embodiment, at least a part of the rolling elements of the rolling bearing 38b on the inboard side. However, it is desirable to arrange | position in the area | region 72 of the direction where the resultant force R goes.

As described above, when the direction of the axial load generated at the meshing portion of the output gear is “one side in the axial direction” at the time of driving the wheel (typically during forward rotation driving), one axial direction is more than the output gear. It suffices that at least a part of the rolling elements of the rolling bearing located on the side is disposed in the region 72 in the direction in which the resultant force R is directed.

<Detailed configuration example of the deceleration unit>
FIG. 14, FIG. 15A to FIG. 15C, and FIG. 16A to FIG. 16C show detailed configuration examples of the speed reducer constituted by the three-axis parallel shaft type gear reducer as described above. FIG. 14 is a view corresponding to FIG. 1, and is a longitudinal sectional view showing the in-wheel motor drive device 1A according to the embodiment of the present invention cut along a predetermined plane and developed. FIG. 15A to FIG. 15C are diagrams showing the internal structure of the speed reducing portion 31A of the in-wheel motor drive device 1A, and schematically show the state seen from the outboard side. FIG. 16A to FIG. 16C are diagrams showing the internal structure of the speed reducing unit 31A of the in-wheel motor drive device 1A, and schematically show the state viewed from the inboard side.

As shown in these drawings, the casing 10 includes a first case portion 10A including the entire motor casing 29 and a rear portion 39b of the main body casing 39, and a second case portion including a front portion 39f of the main body casing 39. 10B is formed by being joined in the axial direction, and the cylindrical portion of the main body casing 39 is divided into a first case portion 10A and a second case portion 10B in the axial direction. 15A to 15C show the state of the first case portion 10A viewed from the outboard side, and FIGS. 16A to 15C show the state of the second case portion 10B viewed from the inboard side. Yes. 15A and 16A are front views, FIGS. 15B and 16B are perspective views seen from the vehicle rear side, and FIGS. 15C and 16C are perspective views seen from the vehicle front side.

14 is the same as the in-wheel motor drive device 1 shown in FIGS. 1 and 2 in itself. Note that the in-wheel motor drive device 1A disposed in the inner space of the wheel wheel W is connected to a vehicle body (not shown) via the suspension device 100 as shown in FIG. The suspension device 100 is, for example, a strut suspension device, and includes a lower arm 101 extending in the vehicle width direction and a damper 102 disposed above the lower arm 101 and extending in the vertical direction.

Similarly to the above, the reduction unit 31A of the in-wheel motor drive device 1A is also provided on the input shaft 32, the intermediate shaft 35, the output shaft 38, the input gear 33 provided on the input shaft 32, and the intermediate shaft 35. Intermediate gears 34, 36, an output gear 37 provided on the output shaft 38, and rolling bearings 32a, 35a, 38a, 32b, 35b, 38b for supporting these shafts 32, 35, 38. In the following description, the direction along the axes M, N, and O is referred to as “axial direction”.

The features relating to the gear and the gear shaft constituting the speed reducing portion 31A, the features relating to the gear peripheral components, the features relating to the arrangement of the gears, and the features relating to the casing 10 will be specifically described with reference to FIGS.

17 to 24 are diagrams schematically showing a gear assembly including the gears 33, 34, 36, and 37 and the gear shafts 32, 35, and 38 of the speed reducing portion 31A. FIG. 17 corresponds to FIG. 15A and is a view of the gear assembly as seen from the outboard side. FIG. 18 corresponds to FIG. 16A and is a view of the gear assembly as viewed from the inboard side. FIG. 19 is a view of the gear assembly as viewed from the rear of the vehicle, and corresponds to a view as viewed from the XIX direction of FIG. FIG. 20 is a view of the gear assembly as viewed from the front of the vehicle, and corresponds to a view as viewed from the XX direction of FIG. FIG. 21 is a view of the gear assembly as viewed from above the vehicle, and corresponds to a view as seen from the XXI direction of FIG. FIG. 22 is a view of the gear assembly as viewed from below the vehicle, and corresponds to a view of the gear assembly as viewed from the direction XXII in FIG. FIG. 23 corresponds to FIG. 15C and is a perspective view of the gear assembly as seen from the outboard side and from the front of the vehicle. FIG. 24 corresponds to FIG. 16C and is a perspective view of the gear assembly as seen from the inboard side and from the front of the vehicle.

FIG. 25 and FIG. 26 are developed sectional views showing a part of the deceleration portion 31A in an enlarged manner, and correspond to a part of FIG. FIG. 25 is an enlarged view of a portion including the input shaft 32 and the intermediate shaft 35, and FIG. 26 is an enlarged view of a portion including the output shaft 38. FIG. 27 is a diagram schematically showing the position of the oil level when the vehicle is stationary and when accelerating. FIG. 27A shows a stationary state and FIG. 27B shows an accelerated state.

Features related to gears and gear shafts In the following (1) to (10), features related to the gears 33, 34, 36, 37 and the gear shafts 32, 35, 38 will be described in detail.

(1) Gear Twist Direction The in-wheel motor drive device 1A is mounted on left and right wheels (left wheel and right wheel) of the vehicle. It is desirable that the torsional directions of the gears included in the speed reduction portion 31A are symmetrical between the left wheel and the right wheel. As a result, in each of the left wheel and the right wheel, the axial load is applied to the meshing portion of each gear on the same side (outboard side or inboard side), so that the load conditions are symmetrical. Therefore, the in-wheel motor drive device 1A can be made compact.

For example, when the twist direction of each gear of the left wheel is the input gear 33 is left, the intermediate gear 34 is right, the intermediate gear 36 is right, and the output gear 37 is left, the twist direction of each gear of the right wheel is 33 is right, the intermediate gear 34 is left, the intermediate gear 36 is left, and the output gear 37 is right.

(2) Gear Module Referring to FIG. 17, the second stage of the gears 33, 34, 36, and 37 constituting the speed reduction unit 31 </ b> A is larger than the first stage. That is, the module of the small-diameter intermediate gear 36 and the large-diameter output gear 37 constituting the second stage is larger than the module of the input gear 33 and the large-diameter intermediate gear 34 constituting the first stage. The module is a numerical value obtained by dividing the pitch circle diameter of the gear by the number of gears, and generally represents the size of the tooth.

Since the torque in the second stage is larger than that in the first stage, it is necessary to increase the strength of the gears 36 and 37 constituting the second stage. The strength (tooth surface, bending strength) of the gear is determined by the reference pitch circle diameter. Increasing the gear diameter to increase strength increases the number of teeth and increases the vibration frequency. Therefore, the vibration frequency can be lowered by making the module of the second gears 36 and 37 larger than the gears 33 and 34 of the first gear to reduce the number of teeth. Thereby, an unpleasant high frequency vibration can be suppressed.

For example, the modules of the second gears 36 and 37 are 1.5 times or more and less than 2.0 times the modules of the first gears 33 and 34. As an example, the module of the first-stage intermediate gear 34 is set to 1.75, and the module of the second-stage output gear 37 is set to 2.73.

(3) Number of gear teeth on each shaft Referring to FIG. 15A and FIG. 16A, in each gear shaft constituting the reduction portion 31A, both ends of the gear shaft are larger than the number of gear teeth provided coaxially with the gear shaft. The number of steel balls in the rolling bearing that supports is smaller. Specifically, with respect to the input shaft 32 as one axis, the number of rolling elements of the outboard side rolling bearing 32a (for example, nine) and the number of rolling elements of the inboard side rolling bearing 32b (for example, nine). Is less than the number of teeth of the input gear 33 (for example, 17). Regarding the intermediate shaft 35 as the two shafts, the number of rolling elements of the outboard side rolling bearing 35a (for example, eight) and the number of rolling elements of the inboard side rolling bearing 35b (for example, eighteen) are small in diameter. The number of teeth of the intermediate gear 36 (for example, 19) and the number of teeth of the large-diameter intermediate gear 34 (for example, 76) are smaller.

Regarding the output shaft 38 as three axes, the number of rolling elements (for example, 26) of the rolling bearing 38a on the outboard side and the number of rolling elements (for example, 7) of the rolling bearing 38b on the inboard side are output. Less than the number of teeth of the gear 37 (for example, 47).

Thus, for each gear shaft, the number of steel balls of the support bearing is made smaller than the number of gear teeth and the order of the forced vibration component is separated to reduce vibration during driving.

(4) Tip diameter of the single-shaft gear The tip diameter of the input gear 33 provided coaxially with the input shaft 32 is smaller than the inner diameter of the outer ring of the support bearings 32 a and 32 b of the input shaft 32. In the present embodiment, the rolling bearings 32a and 32b have the same structure and size.

Specifically, referring to FIG. 25, the tooth tip diameter (maximum outer diameter) D1 of the input gear 33 is smaller than the (minimum) inner diameter dimension D2 of the outer rings of the rolling bearings 32a and 32b. That is, the entire outer ring of the rolling bearings 32 a and 32 b is located radially outside the tooth tip of the input gear 33. Therefore, as shown in FIG. 15A, when the speed reduction portion 31A is viewed from the outboard side, the input gear 33 is hidden by the rolling bearing 32a. Similarly, as shown in FIG. 16A, even when the speed reduction portion 31A is viewed from the inboard side, the input gear 33 is hidden by the rolling bearing 32b.

小 さ く By reducing the tooth tip diameter of the input gear 33 in this way, lubricating oil is easily supplied to the rolling elements of the rolling bearings 32a and 32b, so that poor lubrication of the rolling bearings 32a and 32b can be prevented.

(5) Single-axis spline fitting portion Referring to FIG. 25, the axial position of spline fitting portion 81, which is the portion where input shaft 32 and motor rotating shaft 22 are spline-fitted, is the tooth of input gear 33. It overlaps with the axial position. Specifically, the axial position of the spline fitting portion 81 substantially coincides with the axial position of the teeth of the input gear 33, and the input shaft 32 and the protruding portion 22 e of the motor rotating shaft 22 are connected to the input gear 33. Are fitted within the range of the tooth width D3.

In the speed reduction part 31A, the tooth width D3 of the input gear 33 is larger than that shown in FIG. 1, and is substantially equal to the distance (axial distance) between the rolling bearings 32a and 32b of the input shaft 32 (slightly smaller than that). ). In this case, the tip end position of the protrusion 22e of the motor rotating shaft 22 is located near the boundary position between the input gear 33 and the rolling bearing 32a on the outboard side.

Thereby, the load point of the spline fitting portion 81 is in the vicinity of the center position L14 of both the bearings 32a and 32b in the axial direction, so that the input shaft 32 is not easily tilted. By reducing the inclination of the input shaft 32, misalignment of the input gear 33 can be reduced, so that vibration during driving can be reduced.

(6) Biaxial hollow structure Referring to FIG. 25, intermediate shaft 35 has a hollow structure. That is, the intermediate shaft 35 has a hollow hole 86 penetrating in the axial direction. Thereby, the hollow hole 86 can be made into the passage of lubricating oil. Specifically, the lubricating oil can flow from the inboard side to the outboard side through the hollow hole 86. Therefore, it is possible to cool the rolling bearing 35a on the outboard side that is close to the brake disk and tends to become high temperature.

(7) Two-shaft thinning structure Referring to FIG. 25, a concave portion (thickening) 87 is provided on the end surface of the intermediate shaft 35 on the inboard side. As shown in FIGS. 18 and 24, the recess 87 is formed in an annular shape around the hollow hole 86 around the axis N as viewed from the inboard side. The recess 87 is tapered so as to move away from the back surface portion 39b of the casing 10 as it approaches the center (axis N side).

This makes it possible to reduce the weight of the intermediate shaft 35 as compared with a configuration in which the recess 87 is not provided. As a result, since the in-wheel motor drive device 1A can be reduced in weight, the unsprung weight can be reduced, and deterioration in riding comfort can be prevented.

Also, the lubricating oil can be effectively recovered by making the recess 87 tapered. The collected lubricating oil is guided through the hollow hole 86 to the rolling bearing 35a on the outboard side.

(8) Connection structure of two shafts and two intermediate gears A large diameter intermediate gear 34 and a small diameter intermediate gear 36 are coaxially connected to the intermediate shaft 35. As shown in FIG. 25, the large-diameter intermediate gear 34 is integrally formed with the intermediate shaft 35, whereas the small-diameter intermediate gear 36 is separate from the intermediate shaft 35, and the intermediate shaft 35 is splined. It is fitted (press-fit).

As described above, since one of the intermediate gears 34 and 36 is spline fitted to the intermediate shaft 35, the intermediate gears 34 and 36 can be individually processed, so that the intermediate gears 34 and 36 are easily processed. Therefore, the manufacturing cost of the in-wheel motor drive device 1A can be reduced.

(9) Triaxial (gear) thinning structure Referring to FIG. 26, a recess (thickening) 88 is provided on the end face of the output gear 37 formed integrally with the output shaft 38. As shown in FIGS. 18 and 24, the recess 89 is formed in an annular shape around the output shaft 38 around the axis O as viewed from the inboard side.

Thereby, the space between the output gear 37 and other components (the intermediate gear 34 and the casing 10) is widened at the position of the recess 88. Therefore, since the lubricating oil easily enters the recess 88, the lubricating performance can be ensured even if the clearance between the parts is reduced in order to shorten the axial dimension of the speed reducing portion 31A.

Further, the output gear 37 can be reduced in weight as compared with a configuration in which the recess 88 is not provided. As a result, since the in-wheel motor drive device 1A can be reduced in weight, the unsprung weight can be reduced, and deterioration in riding comfort can be prevented.

(10) Integral structure of three shafts and pump shaft Referring to FIG. 26, an oil pump 42 is attached to the inboard side end portion of the output shaft 38. That is, the pump shaft 43 to which the oil pump 42 is attached is formed integrally with the output shaft 38. The pump shaft 43 is located further on the inboard side than the rolling bearing 38b on the inboard side. Thus, since the number of parts can be reduced by integrating the pump shaft 43 with the output shaft 38, the manufacturing cost of the in-wheel motor drive device 1A can be reduced.

Also, by integrally molding the pump shaft 43 with the output shaft 38, the coaxiality of both shafts can be easily obtained during processing, so that the rotational loss of the oil pump 42 can be reduced and the pump efficiency can be increased. Thereby, since the discharge amount of the oil pump 42 can be ensured, the oil pump 42 can be made compact.

The oil pump 42 is a trochoid pump having an outer rotor and an inner rotor, for example. Referring to FIGS. 15A to 15C, oil pump 42 sucks lubricating oil from oil tank 40 via suction oil passage 41, and discharges the sucked lubricating oil to a discharge oil passage (not shown). The discharge oil passage includes a rising oil passage (not shown) formed in the wall thickness of the motor casing cover 29v. The casing casing 29v is located on the inboard side of the first case portion 10A and constitutes a third case portion that is axially connected to the first case portion 10A.

The ascending oil passage extends in the vertical direction, and is connected to one end of the oil supply pipe 44 at the upper end. The oil supply pipe 44 extends in the axial direction through the back surface portion 39 b in the upper part of the casing 10. That is, the oil supply pipe 44 has a portion arranged in the motor chamber 20 and a portion arranged in the deceleration chamber 30, and the other end of the oil supply tube 44 is arranged in the deceleration chamber 30. . The motor chamber 20 is a space in the motor casing 29 and is located on the inboard side with respect to the back surface portion 39b. The deceleration chamber 30 is a space in the main body casing 39 and is located on the outboard side with respect to the back surface portion 39b.

The oil supply pipe 44 is provided with a through-hole (hereinafter referred to as “oil hole”) for discharging lubricating oil on both the motor chamber 20 side and the deceleration chamber 30 side. Thereby, the lubricating oil flowing through the oil supply pipe 44 is discharged in the radial direction from the oil hole in each chamber. The oil supply pipe 44 may be constituted by a single tubular member, or may be constituted by a plurality of tubular members.

Features related to gear peripheral parts In the following (11) to (14), characteristics related to peripheral parts of the gears 33, 34, 36, and 37 will be described in detail.

(11) Oil Supply Member With reference to FIG. 25, an oil supply member 65 is provided on the outboard side of the input shaft 32. The oil supply member 65 is configured by a dish-like member formed in an annular shape around the axis M. The oil supply member 65 faces the end surface on the outboard side of the input shaft 32 and extends in the radial direction from the annular bottom surface portion 65a to the motor rotating shaft 22 side (inboard side) from the inner diameter edge of the bottom surface portion 65a. And an outer cylindrical portion 65c extending in the axial direction from the outer diameter edge of the bottom surface portion 65a toward the rolling bearing 32a (inboard side).

The inner cylindrical portion 65b is disposed closer to the inner diameter side than the fitting position (spline fitting portion 81) between the input shaft 32 and the motor rotating shaft 22. The outer cylindrical portion 65c is disposed on the outer diameter side of the inner ring of the rolling bearing 32a. The inner cylindrical portion 65b is longer in the axial direction than the outer cylindrical portion 65c, and the inboard side end of the inner cylindrical portion 65b is located in the hollow hole 32h of the input shaft 32. The outer cylindrical portion 65c is disposed with a gap between the outer cylindrical portion 65c and the outer ring of the rolling bearing 32a.

The oil supply member 65 is fitted into a recess formed on the inner end surface of the front portion 39f of the main body casing 39 (second case portion 10B). In this manner, by providing the oil supply member 65 on the outboard side of the input shaft 32, the rolling bearing 32a on the outboard side that is likely to become high temperature due to the heat of the brake disk can be effectively cooled. Moreover, since lubricating oil can be supplied to the spline fitting part 81, wear of the spline part of the input shaft 32 and the motor rotating shaft 22 can be reduced.

(12) Oil supply pipe An oil supply pipe 44 for dropping lubricating oil is disposed above the input shaft 32. Referring to FIGS. 15A to 15C, in the deceleration chamber 30, the oil supply pipe 44 is disposed in front of the large-diameter intermediate gear 34 and above the input gear 33. Thereby, since lubricating oil is supplied to the input gear 33 from above (from the outer diameter side) via the oil supply pipe 44, seizure of the tooth surface of the input gear 33 rotating at high speed can be prevented. Accordingly, it is possible to prevent a failure of the speed reducing portion 31A.

(13) O-ring Referring to FIG. 26, an O-ring 66 is provided in front of the spline portion 82 of the output shaft 38 (inboard side). The spline portion 82 is provided on the outer peripheral surface of the end portion on the outboard side of the output shaft 38, and has a spline groove that fits with the inner ring 12 (rotating wheel) of the wheel hub bearing portion 11.

The output shaft 38 and the inner ring 12 are loosely fitted, and grease is sealed in the spline fitting portion 83. The O-ring 66 is disposed on the inboard side with respect to the spline fitting portion 83 between the output shaft 38 and the inner ring 12, and seals the annular gap between the output shaft 38 and the inner ring 12, whereby the spline fitting portion 83. Grease can be kept on. That is, it is possible to prevent the grease from flowing out from the spline fitting portion 83 to the deceleration chamber 30. Therefore, wear of the spline portion 82 of the output shaft 38 and the spline portion of the inner ring 12 can be prevented.

(14) Spacer A spacer is provided on the inboard side of each gear shaft. Specifically, referring to FIGS. 25 and 26, a spacer 67 is provided on the inboard side of the input shaft 32. A spacer 68 is provided on the inboard side of the intermediate shaft 35. A spacer 69 is provided on the inboard side of the output shaft 38. The spacers 67 to 69 are formed of an annular disk member extending in the radial direction about each axis.

The spacer 67 is disposed between the outer ring of the rolling bearing 32 b that supports the inboard side end of the input shaft 32 and the back portion 39 b of the main body casing 39. The spacer 68 is disposed between the outer ring of the rolling bearing 35 b that supports the inboard side end portion of the intermediate shaft 35 and the back surface portion 39 b of the main body casing 39. The spacer 69 is disposed between the outer ring of the rolling bearing 38 b that supports the inboard side end of the output shaft 38 and the back surface portion 39 b of the main body casing 39.

That is, the spacers 67 to 69 are fitted to the outer rings of the rolling bearings 32b, 35b, and 38b and the bearing portions formed on the back surface portion 39b so as to contact the inboard side end surfaces of the outer rings of the rolling bearings 32b, 35b, and 38b, respectively. It is provided between the outboard side end faces of the portions 32c, 35c, and 38c.

This makes it possible to fill in the axial gap between parts for each gear shaft (to reduce backlash), thereby reducing vibration during driving. Further, the difference in the axial gap can be absorbed by adjusting the thickness of the spacers 67-69. In this case, since it is possible to set the accuracy required for the components of the speed reduction portion 31A to be low, it is possible to reduce the manufacturing cost of the speed reduction portion 31A.

In addition, when the in-wheel motor drive device 1A is assembled, the first case portion 10A has a matching surface 91 (with the second case portion 10B) (FIGS. 15A to 15C) facing upward in the first case portion 10A. Assemble the parts of the speed reducing portion 31A from above. Therefore, since the spacers 67 to 69 can be inserted into the bearing fitting portions 32c, 35c, and 38c formed on the back surface portion 39b of the first case portion 10A from above, the spacers 67 to 69 are displaced. Difficult and easy to assemble.

Features regarding arrangement of gears, gear shafts, and bearings In the following (15) to (18), gears 33, 34, 36, 37, gear shafts 32, 35, 38, and rolling bearings that support the gear shafts Features regarding the arrangement will be specifically described.

(15) Position of single-shaft outboard side bearing Referring to FIG. 25, the outboard side rolling bearing 32a of the input shaft 32 is more than the outboard side rolling bearings 35a, 38a of the other shafts 35, 38. Close to the inboard. Specifically, the axial position L11 of the rolling bearing 32a of the input shaft 32 is more inboard than the axial position L12 of the rolling bearing 35a of the intermediate shaft 35 and the axial position L13 of the rolling bearing 38a of the output shaft 38. On the side. In the illustrated example, the axial position L11 of the rolling bearing 32a of the input shaft 32 is included in the axial range of the meshing portion between the intermediate gear 36 and the output gear 37.

Therefore, the axial distance between the rolling bearings 32a and 32b of the input shaft 32 is larger than the axial distance between the rolling bearings 35a and 35b of the intermediate shaft 35 and the axial distance between the rolling bearings 38a and 38b of the output shaft 38. Is also small. Thereby, in the input shaft 32, the load received by the inboard side rolling bearing 32b can be shared by the outboard side rolling bearing 32a. Therefore, the size (width dimension) of the inboard rolling bearing 32b can be made relatively small. As a result, the protruding amount of the protruding portion 22e of the motor rotating shaft 22 fitted to the input shaft 32 can be suppressed.

Furthermore, since the rolling bearing 32a of the input shaft 32 can be moved away from the brake disk more than the rolling bearings 35a and 38a on the other outboard side, the rolling bearing 32a that rotates at high speed is less likely to be affected by heat. it can. Thereby, since the peeling of the rolling surface due to the hardness reduction of the rolling bearing 32a can be prevented, it is possible to prevent the generation of noise and vibration during driving.

(16) Vertical Position of One Axis Referring to FIG. 15A, the input shaft 32 is located above the axle. That is, the axis M of the input shaft 32 is located above the axis O of the output shaft 38. In FIG. 15A, the vertical position (height) of the axis O is indicated by a one-dot chain line L21.

As described above, the input shaft 32 is arranged at a position higher than the axis O, and the input shaft 32 is moved away from the oil surface of the lubricating oil stored in the oil tank 40, so that the stirring resistance of the input shaft 32 rotating at high speed can be reduced. Can be reduced. Thereby, the efficiency of 1 A of in-wheel motor drive devices can be improved.

(17) One-shaft support bearing and two-shaft large-diameter gear Referring to FIGS. 14, 15A, and 16A, an outboard-side rolling bearing 32a and an inboard-side rolling bearing 32b of the input shaft 32 are When viewed in the direction, it overlaps the large-diameter intermediate gear 34. Thereby, the physique of 31 A of deceleration parts can be made compact in radial direction. As a result, the in-wheel motor drive device 1A can be made compact.

(18) 3-axis inboard side bearing and 2-axis large diameter gear Referring to FIGS. 14 and 16A, the inboard side rolling bearing 38b of the output shaft 38 is viewed in the axial direction (from the inboard side). And overlaps with the large-diameter intermediate gear 34. Thereby, the in-wheel motor drive 1A provided with 31 A of deceleration parts and 31 A of deceleration parts can be made compact similarly to (17).

Features relating to the casing In the following (19) to (21), features relating to the casing 10 (the first case portion 10A and the second case portion 10B) that accommodates the speed reducing portion 31A will be specifically described.

(19) Bearing fitting portion on the biaxial inboard side Referring to FIG. 25, the bearing fitting portion 35c of the rolling bearing 35b on the inboard side of the intermediate shaft 35 is thick. In other words, the radial thickness of the cylindrical portion constituting the bearing fitting portion 35c is relatively large. Thereby, since the intensity | strength and rigidity of the bearing fitting part 35c can be improved, the inclination of the intermediate shaft 35 can be suppressed. Therefore, the misalignment of the intermediate gears 34 and 36 provided coaxially with the intermediate shaft 35 can be reduced, and the vibration of the meshing portions of the intermediate gears 34 and 36 can be suppressed.

(20) Shape of Cylindrical Part of Casing Referring to FIGS. 15A and 16A, the wall part located on the vehicle rear side of the cylindrical part (outer part) of casing 10 (main body casing 39) has a large diameter. The intermediate gear 34 and the output gear 37 are close to the tooth surfaces (outer peripheral surfaces) and along the common tangent line of these gears 34 and 38.

Specifically, as shown in FIG. 15A, the shape of the wall portion 84 on the vehicle rear side in the cylindrical portion of the first case portion 10 </ b> A has a common tangent L <b> 22 between the large-diameter intermediate gear 34 and the output gear 37. The shape is along. Similarly, as shown in FIG. 16A, the shape of the wall portion 85 on the vehicle rear side in the cylindrical portion of the second case portion 10B is along the common tangent L23 between the large-diameter intermediate gear 34 and the output gear 37. It has a shape. It is sufficient that at least the wall portion 84 of the first case portion 10A has a shape along the common tangent line L22. That is, at least the wall portion 84 in the first case portion 10 </ b> A is not curved along the outer peripheral surfaces of the large-diameter intermediate gear 34 and the output gear 37.

Thus, the wall portion 84 of the first case portion 10A serves as a lubricating oil guide surface, and the lubricating oil splashed up by the output gear 37 can be efficiently supplied to the intermediate gear 34 through the wall portion 84.

(21) The mating surface of the first case portion and the second case portion As shown in FIG. 14, the cylindrical portion of the first case portion 10A and the cylindrical portion of the second case portion 10B are the respective mating surfaces. They are abutted in the axial direction at 91 and 92 and fixed to each other by bolts 64. The mating surface 91 of the first case portion 10A corresponds to the end surface on the outboard side of the cylindrical portion, and the mating surface 92 of the second case portion 10B corresponds to the end surface on the inboard side of the cylindrical portion.

The position L10 of the mating surfaces 91 and 92 of the first case portion 10A and the second case portion 10B is near the boundary position between the large diameter intermediate gear 34 and the small diameter intermediate gear 36. For example, the entire large-diameter intermediate gear 34 is located on the inboard side with respect to the position L10 of the mating surface. The entire large-diameter output gear 37 that meshes with the small-diameter intermediate gear 36 is located on the outboard side from the position L10 of the mating surface.

Accordingly, the radial size of the cylindrical portion of the first case portion 10A can be matched with the outer diameter of the large-diameter intermediate gear 34, and the radial size of the cylindrical portion of the second case portion 10B. Can be adjusted to the outer diameter of the large-diameter output gear 37. Therefore, the outer shape of each case part 10A, 10B can be made compact. As a result, the internal parts of the speed reducing part 31A and the wall parts (inner wall surfaces) of the case parts 10A and 10B are close to each other, so that the lubricating performance of the internal parts is improved.

(22) Oil Tank As shown in FIG. 15A, FIG. 16A, etc., the oil tank 40 formed in the lower part of the main body casing 39 (the first case portion 10A and the second case portion 10B) is formed from the axle (axis O). Is also arranged in front of the vehicle. The oil tank 40 is configured by a protruding portion that protrudes downward from the lower end position of the output gear 37, and is positioned below the input shaft 32.

The position of the oil level of the lubricating oil stored in the oil tank 40 will be described with reference to FIG. FIG. 27A schematically shows the position of the oil level when the vehicle is stationary, and FIG. 27B schematically shows the position of the oil level when the vehicle is accelerated. The position of the oil level when the vehicle is stationary is represented by a dashed line L31, and the position of the oil level when the vehicle is accelerated is represented by a dashed line L32. FIGS. 27A and 27B are views corresponding to FIG. 15A.

27A, the position of the oil level when the vehicle is stationary is below the lower end position of the output gear 37. On the other hand, as shown in FIG. 27 (B), when the vehicle is accelerated, the in-wheel motor drive device 1A is inclined toward the rear side of the vehicle, so that the oil level is inclined rearward. More specifically, the vertical line LO passing through the axis O when stationary is inclined rearward relative to the vertical line LO ′ passing through the axis O during acceleration. Therefore, the position of the oil level during acceleration is above the lower end position of the output gear 37. That is, the output gear 37 has a structure that is difficult to be immersed in the lubricating oil except during acceleration.

Therefore, since the lubricating oil can be supplied to the output gear 37 only when necessary (acceleration), the rotational resistance of the output gear 37 can be reduced. As a result, the efficiency of the deceleration unit 31A can be improved.

(Other variations)
In the above embodiment, the rotating wheel of the wheel hub bearing portion 11 is an inner ring, but the rotating wheel may be an outer ring.

In the above-described embodiment, the example in which the speed reducing unit 31 is a three-axis parallel shaft type gear reducer has been described. However, the speed reducing unit may be another type of gear reducer such as a four-axis parallel shaft type gear reducer. It may be.

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

1,1A In-wheel motor drive device, 10 casing, 11 wheel hub bearing part, 12 inner ring, 13 outer ring, 14, 73, 74, 173 rolling element, 21 motor part, 22 motor rotating shaft, 23 rotor, 24 stator, 25 Stator core, 26 coils, 27, 28, 32a, 32b, 35a, 35b, 38a, 38b, 138a rolling bearing, 29 motor casing, 29v motor casing cover, 31 speed reducer, 32 input shaft, 33 input gear, 34, 36 intermediate Gear, 35 intermediate shaft, 37 output gear, 38 output shaft, 39 body casing, M, N, O axis, W wheel wheel.

Claims (6)

1. A wheel hub bearing having a rotating wheel to which the wheel is attached;
   An output shaft coupled to the rotating wheel of the wheel hub bearing portion; an output gear that is a helical gear provided coaxially with the output shaft; an intermediate shaft provided in parallel with the output shaft; An intermediate gear, which is a helical gear that is provided coaxially with the intermediate shaft and meshes with the output gear, and a rolling bearing that is disposed on one side in the axial direction of the output gear and rotatably supports the output shaft. Including a reduction part including,
   The direction of the axial load generated in the meshing portion of the output gear when driving the wheel is one side in the axial direction,
   At least a part of the rolling elements of the rolling bearing is disposed in a region in a direction in which a resultant force of an axial load and a radial load applied from one axial end to the other end of the meshing portion of the output gear is directed. Wheel motor drive device.
2. The output gear has a twist angle β and a pressure angle α;
   The region in the direction in which the resultant force is directed includes a first straight line extending from one end in the axial direction of the meshing portion of the output gear at an inclination angle of θ relative to the radial direction, and the other in the axial direction of the meshing portion of the output gear. A region sandwiched between a second straight line extending at an inclination angle of θ relative to the radial direction from the end,
   The in-wheel motor drive device according to claim 1, wherein the angle θ = atan {tan β / (tan α / cos β)}.
3. Further comprising a casing for accommodating the deceleration portion;
   The in-wheel motor drive device according to claim 1 or 2, wherein the rolling bearing is disposed between an outer diameter surface of the output shaft and a cylindrical surface formed in the casing.
4. An annular convex portion is provided on one axial end surface of the output gear,
   The in-wheel motor drive device according to claim 3, wherein the rolling bearing is accommodated between the annular convex portion and the cylindrical surface of the casing.
5. The in-wheel motor drive device according to any one of claims 1 to 4, wherein the speed reducing portion further includes a rolling bearing disposed on the other side in the axial direction from the output gear and rotatably supporting the output shaft.
6. The in-wheel motor drive device according to any one of claims 1 to 5, wherein one side in the axial direction is an outer side in the vehicle width direction.

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