JP2017171251A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure desired motor output while avoiding interference with a vehicle body and an adjacent link member when arranging a motor and a reduction gear in a case inner space of a unit case.SOLUTION: An in-wheel motor drive device A includes: an in-wheel motor unit 1; and a strut type suspension 3. In the strut type suspension 3 in the in-wheel motor drive device A, a lower end portion of a strut 31 is mounted at an upper position of a unit case 10. In the in-wheel motor unit 1, a motor generator 5 is arranged at the vehicle outside of the mounting position of the strut 31, and a reduction gear mechanism 6 is arranged at the vehicle inside opposite to the motor generator 5 with respect to the mounting position of the strut 31 in an axle direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an in-wheel motor drive device in which an in-wheel motor unit having a motor and a reduction gear is suspended on a vehicle body by a strut suspension.

  Conventionally, the rotational force of a motor disposed in a wheel is decelerated by a plurality of speed reducers and transmitted to the wheel so that the wheels can be driven, and the first speed reducer and the second speed reducer are driven in the axle direction. Place the motor in between. And the wheel drive device which arrange | positions the drive shaft of a motor and the output shaft of each reduction gear in parallel mutually is known (for example, refer patent document 1).

JP 2008-184110 A

  However, in the wheel drive device of the prior art, the in-wheel motor unit pays attention to how efficiently the motor and the speed reducer are arranged with respect to the unit case. For this reason, when the wheel drive device of the prior art is suspended on the vehicle body by the strut suspension, the following problems occur.

  When the motor is disposed on the vehicle inner side than the strut, the unit case protrudes greatly toward the vehicle inner side at the time of steering or suspension stroke, and the protrusion of the unit case may interfere with the vehicle body or an adjacent link member. On the other hand, when the motor is arranged on the vehicle outer side from the strut, the second reduction gear is arranged further on the vehicle outer side than the motor, so that the axial length of the motor is the axial length occupied by the second reduction gear. We are restricted by this. For this reason, sufficient motor volume cannot be taken and a desired motor output cannot be ensured.

  The present invention has been made paying attention to the above problem, and when arranging a motor and a speed reducer in a case inner space of a unit case, a desired motor output can be obtained while avoiding interference with a vehicle body and an adjacent link member. It aims at providing the in-wheel motor drive device to ensure.

In order to achieve the above object, an in-wheel motor drive device of the present invention includes an in-wheel motor unit and a strut suspension.
In this in-wheel motor drive device, the strut suspension has the lower end portion of the strut attached to the upper position of the unit case.
In the in-wheel motor unit, the motor is arranged outside the vehicle in the axle direction from the strut mounting position, and the reduction gear is arranged inside the vehicle on the opposite side of the motor from the strut mounting position in the axle direction. .

  As a result, when the motor and the speed reducer are arranged in the case space of the unit case, a desired motor output can be ensured while avoiding interference with the vehicle body and adjacent link members.

It is an in-wheel motor drive device of the 1st example, and is a perspective view showing the state where an in-wheel motor unit is suspended by the body by a strut type suspension. It is a perspective view which shows the external appearance of the in-wheel motor unit to which the strut was attached in the in-wheel motor drive device of 1st Example. It is a partially broken perspective view which shows the schematic structure of the in-wheel motor unit to which the strut and the wheel were attached in the in-wheel motor drive device of 1st Example. It is an expanded sectional view showing the internal structure of an in-wheel motor unit in the in-wheel motor drive device of the 1st example. It is a perspective view which shows the arrangement configuration by the positional relationship of the motor generator, the inverter heat radiating plate, the reduction gear mechanism, the strut, and the wheel hub in the axle direction in the in-wheel motor drive device of the first embodiment. FIG. 3 is an axle direction view showing an arrangement configuration of a motor generator, a reduction gear mechanism, a strut, a tie rod coupling portion, and a brake caliper in the in-wheel motor driving device of the first embodiment according to the positional relationship in the direction perpendicular to the axle and in the circumferential direction. is there. FIG. 5 is an explanatory diagram of the replacement action of the in-wheel motor unit showing that it can be replaced with the in-wheel motor unit using the strut type front suspension of the electric vehicle that drives the left and right front wheels by the drive shaft as it is. It is an in-wheel motor unit displacement action explanatory view at the time of steering operation which shows displacement operation of an in-wheel motor unit at the time of steering operation in the in-wheel motor drive device of the 1st example. It is a transverse link displacement action explanatory view at the time of full rebound which shows displacement operation of a transverse link at the time of full rebound of a suspension in an in-wheel motor drive of a 1st example.

  Hereinafter, the best mode for realizing the in-wheel motor drive device of the present invention will be described based on a first embodiment shown in the drawings.

First embodiment

First, the configuration will be described.
The in-wheel motor drive apparatus according to the first embodiment is an example applied to each of left and right front wheels (drive wheels, steered wheels) suspended on a vehicle body by a strut suspension in an in-wheel motor vehicle driven by front wheels. Hereinafter, the configuration of the first embodiment will be described by dividing it into “the overall device configuration”, “the internal detailed configuration of the in-wheel motor unit”, and “the layout layout configuration of each component”.

[Overall system configuration]
FIG. 1 shows an in-wheel motor drive apparatus according to a first embodiment, in which the in-wheel motor unit is suspended from a vehicle body by a strut suspension. FIG. 2 shows the appearance of the in-wheel motor unit to which the strut is attached. FIG. 3 shows a schematic structure of an in-wheel motor unit to which a strut and a tire wheel are attached.
Hereinafter, based on FIGS. 1-3, the whole apparatus structure of the in-wheel motor drive device of 1st Example is demonstrated.

  As shown in FIG. 1, the in-wheel motor drive device A includes an in-wheel motor unit 1, a tire wheel 2, a strut suspension 3, and a vehicle body 4.

  As shown in FIG. 1, the in-wheel motor unit 1 has a unit case 10 that is disposed in a state where a part of the in-wheel motor unit 1 is inserted into the inner space of the tire wheel 2. As shown in FIG. 2, the unit case 10 includes a motor case 11, a motor cover 12, a reduction gear case 13, and a reduction gear cover 14.

  As shown in FIGS. 1 and 2, a knuckle arm 15, a brake caliper fixing arm 16, and a transverse link support arm 17 are formed on the case outer surface of the motor case 11 so as to protrude integrally with the case. As shown in FIG. 3, the motor generator 5 is arranged in a space in the case formed by the motor case 11 and the motor cover 12.

  The knuckle arm 15 is provided in the motor case 11 also serving as the knuckle body so as to protrude toward the rear of the vehicle at the rear surface position on the tire wheel 2 side in the axle direction. As shown in FIG. 2, a tie rod connection hole 15a to which a tie rod 86 of the steering mechanism is connected is provided at the arm tip of the knuckle arm 15.

  The brake caliper fixing arm 16 is located in the motor case 11 that also serves as the knuckle main body, in a position adjacent to the tire wheel 2 side from the knuckle arm 15 in the axle direction, and toward the vehicle upper side and the vehicle front side in the axle orthogonal direction. Protruding in the direction. As shown in FIG. 2, caliper fixing holes 16 a and 16 b for fixing the brake caliper 93 (see FIG. 6) are provided at the arm tip portion protruding in two directions of the brake caliper fixing arm 16.

  The transverse link support arm 17 of the motor case 11 also serving as a knuckle body is provided to project downward toward the lower side of the vehicle at the lower surface position on the tire wheel 2 side in the axle direction. As shown in FIG. 2, a link support ball 17 a serving as a unit side support of the transverse link 33 is fixed to the arm tip of the transverse link support arm 17.

  As shown in FIGS. 1 to 3, a strut mounting recess 18 is integrally formed on the upper surface of the reduction gear case 13. A reduction gear mechanism 6 (see FIG. 4) is disposed in a case inner space formed by the reduction gear case 13 and the reduction gear cover 14.

  The strut mounting recess 18 is recessed downward in the vehicle so that the lower end portion of the strut 31 is mounted in a flat state at the upper portion of the reduction gear case 13 fixed to the adjacent position of the motor case 11 in an embedded state. It is formed in a cylindrical recess.

  As shown in FIG. 3, the tire wheel 2 is fixed to an end position of a wheel drive shaft 21 that is an output shaft of the in-wheel motor unit 1, and a tire (not shown) is mounted on the outer peripheral portion. That is, the wheel hub 22 is fixed to the end portion of the wheel drive shaft 21 from the reduction gear mechanism 6 by the hub nut 23, and fixed together with the brake rotor 87 by the hub bolt 24.

  The strut suspension 3 is a suspension of a type in which a shock absorber supporting a force acting in the vertical direction of the vehicle is used as a strut 31 (support), and an unsprung member including the in-wheel motor unit 1 is suspended on the vehicle body 6. As shown in FIG. 1, the strut suspension 3 includes a strut 31, a coil spring 32, and a transverse link 33.

  The strut 31 is a suspension member that generates a damping force by a stroke operation while supporting a force acting in the vehicle vertical direction. The lower end portion of the strut 31 is attached in an embedded state to the upper surface position of the reduction gear case 13 that also serves as the knuckle body. The upper end portion of the strut 31 is elastically supported by the wheel house vehicle body member 41 (vehicle body 4) via an upper mount made of a rubber insulator. The strut 31 is attached to the reduction gear case 13 by, for example, screwing and fixing the lower end portion of the strut 31 into the strut attachment recess 18 and then tightening and fixing it with a lock nut for preventing loosening.

  The coil spring 32 has a spring center axis that is offset with respect to the shock absorber center axis, and is disposed at an upper outer peripheral position of the strut 31 to support a force acting in the vehicle vertical direction and generate a spring force by an expansion / contraction operation. It is. A lower end portion of the coil spring 32 is supported by a lower end side spring receiving plate 34 fixed to the strut 31. The upper end portion of the coil spring 32 is elastically supported by the wheel house member 41 (vehicle body 4) through an upper mount by an upper end side spring receiving plate 35 and a rubber insulator.

  The transverse link 33 is a suspension member that supports an unsprung member including the in-wheel motor unit 1 on the front suspension member 42 (vehicle body 4) so as to be swingable, and supports a force acting in the vehicle width direction and the vehicle front-rear direction. is there. The unit case 10 side of the transverse link 33 is spherically supported with respect to a link support ball 17 a provided on the transverse link support arm 17. The front suspension member 42 (vehicle body 4) side of the transverse link 33 is coupled to support pins 33a and 33b provided at positions separated in the vehicle longitudinal direction on the vehicle body support shaft at two points via rubber bushes. Supported.

  Here, when the strut suspension 3 is used for the left and right front wheels as in the first embodiment, the shaft passes through the vehicle body support point P1 of the strut 31 and the coil spring 32 and the unit case support point P2 of the transverse link 33. Is the virtual kingpin axis KL. That is, when a steering operation is performed, the in-wheel motor unit 1 and the tire wheel 2 are steered using the virtual kingpin axis KL as the rotation center axis.

[Detailed internal structure of in-wheel motor unit]
FIG. 4 shows the internal structure of the in-wheel motor unit in the in-wheel motor drive device of the first embodiment. Hereinafter, the detailed internal configuration of the in-wheel motor unit will be described with reference to FIG.

  As shown in FIG. 4, the in-wheel motor unit 1 includes a motor generator 5 (motor), a reduction gear mechanism 6 (reduction gear), and an inverter module 7 in the case of the unit case 10.

  The motor generator 5 includes a motor shaft 51, a rotor 52, a stator 53, and a stator coil 54.

  The motor shaft 51 is formed with a shaft center oil passage 55 penetrating in the center axis position. One end of the motor shaft 51 on the tire wheel 2 side is rotatably supported by the motor case 11 via a first bearing 81. A resolver 89 that detects the rotor rotation angle is provided at one end of the motor shaft 51 on the tire wheel 2 side at a position between the first bearing 81 and the splash guard 88. The other end of the motor shaft 6 on the speed reduction gear mechanism 6 side is rotatably supported by the speed reduction gear case 13 via a second bearing 82.

  The rotor 52 is fixed to the motor shaft 51 and is constituted by a laminated steel plate in which a permanent magnet (not shown) is embedded. A plurality of first air circulation blades 56 are provided in the radial direction on the end surface of the rotor 52 on the speed reduction gear mechanism 6 side, and a second air circulation blade 57 is provided in the radial direction on the end surface of the rotor 52 on the tire wheel 2 side. Multiple sheets are provided. The first air circulation blade 56 has a centrifugal axial flow blade shape used in a turbocharger with the inverter heat radiation plate 71 as a blade casing.

  The stator 53 is fixed to the inner surface of the unit case 1 and is disposed with respect to the rotor 52 via an air gap, and is configured by winding a stator coil 54 around each of stator teeth made of a punched laminated steel plate. Stator coil 54 has a U-phase coil wire, a V-phase coil wire, a W-phase coil wire, and the like, and these coil wires are connected to inverter module 7.

  The space in which the motor generator 5 is disposed is a dry space 58 defined by the partition wall 13a from the wet space 68 in which the reduction gear mechanism 6 is disposed. An internal circulation air cooling path for forcibly circulating the air in the dry space 58 is formed using the first air circulation blade 56 and the second air circulation blade 57 that rotate with the rotation of the rotor 52. The internal circulation air cooling path uses an air gap between the air gap between the rotor 52 and the stator 53, the slit in the rotor, the stator gap, and the inner surface of the case as an air passage. The partition wall 13a of the reduction gear case 13 is provided with ribs 13b that secure a heat exchange area for exchanging heat with the wet space 68.

  The reduction gear mechanism 6 includes a motor shaft 51, an idler shaft 60, and a wheel drive shaft 21 as gear shafts. The gear train includes a first reduction gear train 61 (first reduction gear) and a second reduction gear train 62 (second reduction gear).

  The motor shaft 51, the idler shaft 60, and the wheel drive shaft 21 are gear shafts that are parallel to each other and have different heights. The idler shaft 60 is supported at both ends by a third bearing 83 provided on the partition wall 13 a of the reduction gear case 13 and a fourth bearing 84 provided on the reduction gear cover 14. The wheel drive shaft 21 is supported at both ends by a fifth bearing 85 provided on the reduction gear cover 14 and a hub bearing 25 provided on the wheel hub 22 side. The hub bearing 25 is a bearing in which the hub case 26 fixed to the motor case 11 is an outer race and the wheel hub 22 is an inner race. Here, in the developed cross-sectional view shown in FIG. 4, it is described that the motor shaft 51> idler shaft 60> wheel drive shaft 21 has a height relationship, but the actual height relationship is the idler shaft 60> motor. The relationship of shaft 51> wheel drive shaft 21 is established (see FIG. 6).

The first reduction gear train 61 meshes with the motor shaft gear 63 formed at the end position where the motor shaft 51 extends to the vicinity of the reduction gear cover 14 on the inner side of the vehicle, and is integrally formed with the idler shaft 60. And the first idler shaft gear 64. An axial center oil passage tube 67 is provided at the center axis position of the idler shaft 60. An opening through which the lubricating oil from the third bearing 83 flows is formed at the end position on the partition wall 13 a side of the axial center oil passage tube 67. One end of a bendable connecting tube 90 is connected to the end position of the shaft center oil passage tube 67 on the speed reduction gear cover 14 side, and the other end of the connecting tube 90 is connected to the shaft center oil passage 55 of the motor shaft 51. The
A parking pawl (not shown) is operated on the end face of the first idler shaft gear 64 by selecting the parking range position, and a parking gear 91 for stationaryly fixing the idler shaft 60 to the unit case 10 by engagement with the parking pawl is provided. It has been.

  The second reduction gear train 62 meshes with the second idler shaft gear 65 formed integrally with the idler shaft 60 and the second idler shaft gear 65, and the wheel drive shaft gear formed integrally with the end position of the wheel drive shaft 21. 66. The wheel drive shaft gear 66 can be supported at both ends by a pin bearing 92 on the reduction gear cover 14 side and a fifth bearing 85 on the opposite side across the wheel drive shaft gear 66. The pin bearing 92 includes a case member 92a fixed to the reduction gear case 14 side and a support pin 92b. The case member 92a has a cylindrical protrusion and a pin hole, and the wheel drive shaft gear 66 has a cylindrical recess at a position corresponding to the cylindrical protrusion, and a pin hole at a rotation center axis position corresponding to the pin hole. A support pin 92b is provided through both pin holes of the case member 92a and the wheel drive shaft gear 66. The pin bearing 92 normally has a large gap and does not act as a bearing. However, when the wheel nut 23 is loosened, the hub bearing 25 is abnormal, or the fifth bearing 85 (roller bearing) is abnormal, the gap is filled and acts as a bearing.

  The space in which the reduction gear mechanism 6 is disposed is a wet space 68 defined by the partition wall 13a from the dry space 58 in which the motor generator 5 is disposed. The motor case 11 includes a first lubricating oil passage 94 in the oblique radial direction that communicates the first bearing 81 and the hub bearing 25, and a second lubricating oil passage in the axle direction that communicates the hub bearing 25 and the fifth bearing 85. 95 is formed. That is, the lubricating oil accumulated at the bottom of the speed reducer case 13 is lifted up by the rotating wheel drive shaft gear 66. Then, an internal circulating lubricating oil cooling path is formed in which the raked lubricating oil is forcedly circulated through a portion requiring lubrication from an axial center oil path tube 67 provided on the idler shaft 60. In the internal circulation lubricating oil cooling path, the scraped lubricating oil is a case notch 13c provided outside the third bearing 83 → shaft oil passage tube 67 → connecting tube 90 → shaft oil passage 55 → first bearing. 81 → first lubricating oil path 94 → second lubricating oil path 95 → fifth bearing 85.

  The inverter module 7 is a module that is built in the side surface of the motor generator 5 and includes an inverter circuit using a semiconductor element having high heat resistance. The inverter module 7 is connected to the stator coil 54, and is configured by arranging a plurality of annular shapes with respect to the inverter heat dissipation plate 71. The inverter module 7 converts direct current from a battery (not shown) into multiphase alternating current that drives the motor generator 5 to rotate when the motor generator 5 is powered. Further, when the motor generator 5 is regenerated, the polyphase alternating current generated by the motor generator 5 is converted into direct current for charging a battery (not shown).

  The inverter heat radiating plate 71 is fixed to the motor case 11 with screws, and is disposed adjacent to the motor generator 5 on the reduction gear mechanism 6 side so as to cover the motor end surface (see FIG. 5). The inverter heat dissipation plate 71 has a flat surface as a surface on which the inverter module 7 is fixed, and the opposite surface is formed into a blade casing for the first air circulation blade 56 fixed to the end surface of the rotor 52.

  Here, the space in which the inverter module 7 is disposed is the dry space 58 in which the motor generator 5 is disposed as described above. The inverter module 7 is disposed at the suction position of the first air circulation blade 56 where the air flow is fast in the internal circulation air cooling path for forcibly circulating the air in the dry space 58, and the cooling capacity of the inverter module 7 is increased. Secured.

[Arrangement layout configuration of each component]
FIG. 5 shows an arrangement configuration of the motor generator, the inverter heat radiation plate, the reduction gear mechanism, the strut, and the wheel hub depending on the positional relationship in the axle direction. FIG. 6 shows an arrangement configuration of the motor generator, the reduction gear mechanism, the strut, the tie rod connecting portion, and the brake caliper according to the positional relationship in the direction perpendicular to the axle and in the circumferential direction. Hereinafter, an arrangement layout configuration of each component will be described with reference to FIGS. 5 and 6.

  The reduction gear mechanism 6 includes a first reduction gear train 61 and a second reduction gear train 62. As shown in FIG. 5, the first reduction gear train 61 is disposed at a position on the vehicle inner side away from the motor generator 5 in the axle direction by extending the motor shaft 51 in the vehicle inner direction. On the other hand, as shown in FIG. 5, the second reduction gear train 62 is disposed at a position outside the vehicle relative to the first reduction gear train 61 in the axle direction.

  The first reduction gear ratio by the first reduction gear train 61 and the second reduction ratio by the second reduction gear train 62 are made different. As shown in FIGS. 5 and 6, the first reduction gear train 61 sets the first reduction ratio to be large by reducing the meshing diameter of the motor shaft gear 63 and increasing the meshing diameter of the first idler shaft gear 64. doing. The second reduction gear train 62 sets the second reduction ratio smaller than the first reduction ratio by suppressing the difference between the meshing diameter of the second idler shaft gear 65 and the meshing diameter of the wheel drive shaft gear 66. .

  Further, the motor shaft 51, the idler shaft 60, and the wheel drive shaft 21 are set to have a height relationship of idler shaft 60> motor shaft 51> wheel drive shaft 21, as shown in FIG. That is, when the wheel drive shaft 21 is disposed at the position of the central axis CL of the tire wheel 2, the motor shaft 51 is disposed at a position higher than the wheel drive shaft 21, and the idler shaft 60 is disposed at a position higher than the motor shaft 51. Yes.

The positional relationship in the axle direction when the reduction gear mechanism 6 is not divided into the first reduction gear train 61 and the second reduction gear train 62 is as follows.
As shown in FIG. 5, the motor generator 5, the reduction gear mechanism 6, and the strut 31 have a positional relationship in the axle direction, and the motor generator 5 is disposed on the vehicle outer side than the mounting position of the strut 31 in the axle direction. The reduction gear mechanism 6 is disposed on the vehicle inner side opposite to the motor generator 5 with respect to the mounting position of the strut 31 in the axle direction.

The positional relationship in the axle direction when the reduction gear mechanism 6 is divided into the first reduction gear train 61 and the second reduction gear train 62 is as follows.
The positional relationship of the motor generator 5, the first reduction gear train 61, and the strut 31 in the axle direction is as shown in FIG. 5, with the first reduction gear train 61 and the motor generator 5 sandwiching the strut 31 in the axle direction. Arranged in the opposite area. The positional relationship between the second reduction gear train 62 and the strut 31 in the axle direction is such that the second reduction gear train 62 is disposed in the lower region of the strut 31 as shown in FIG. That is, since the strut 31 is disposed at a position that coincides with the second reduction gear train 62 in the axle direction, the lower end portion of the strut 31 is embedded to the inside of the unit case 10 as shown in FIGS. Space to be arranged in the state is secured.

The positional relationship of the motor shaft gear 63, the first idler shaft gear 64, the second idler shaft gear 65, and the wheel drive shaft gear 66 constituting the reduction gear mechanism 6 in the direction perpendicular to the axle is as follows.
The first reduction gear ratio by the first reduction gear train 61 is made larger, and the second reduction ratio by the second reduction gear train 62 is made smaller than the first reduction gear ratio. For this reason, as shown in FIG. 6, the diameter of the wheel drive shaft gear 66 provided on the wheel drive shaft 21 disposed at the position of the center axis CL of the tire wheel 2 is suppressed to a small value. Therefore, the height occupied by the motor shaft gear 63, the first idler shaft gear 64, the second idler shaft gear 65, and the wheel drive shaft gear 66 is arranged to be substantially within the range of the total height MH of the motor generator. As a result, the bottom surface height position BL of the unit case 10 becomes a height position away from the unit case support point P2 of the transverse link 33.

The positional relationship between the motor generator 5 and the tie rod connecting portion 96 in the direction perpendicular to the axle is as follows.
As shown in FIG. 6, the motor generator 5 is disposed in an axially symmetric region on the opposite side of the knuckle arm 15 from the tie rod coupling portion 96 with the wheel drive shaft 21 sandwiched in the direction orthogonal to the axle. That is, the tie rod coupling portion 96 is disposed in an empty space region formed away from the motor generator 5 in the vehicle front-rear direction.

The positional relationship in the circumferential direction among the motor generator 5, the tie rod connecting portion 96, and the brake caliper 93 is as follows.
As shown in FIG. 6, the brake caliper 93 is disposed in a circumferential region between the tie rod coupling portion 96 of the knuckle arm 15 and the motor generator 5 in the circumferential direction around the wheel drive shaft 21. That is, the brake caliper 93 is disposed in an empty space region formed in the circumferential direction between the tie rod connecting portion 96 and the motor generator 5.

Next, the operation will be described.
The actions of the first embodiment are “in-wheel motor unit replacement action”, “in-wheel motor unit displacement action at full turning”, “transverse link displacement action at full rebound”, “in-wheel motor drive device” This will be explained separately in the “characteristic action of”.

[In-wheel motor unit replacement]
Hereinafter, based on FIG. 7, a replacement operation for attaching the in-wheel motor unit 1 of the first embodiment to the steering knuckle portion using the strut type front suspension of the electric vehicle that drives the left and right front wheels by the drive shaft will be described. .

First, the following points are mentioned as the merits of the strut suspension.
(A) An independent suspension other than the strut type (such as a double wishbone type) requires an upper arm for positioning in the camber direction, and the space is sacrificed. However, in the strut type, the shock absorber plays the role, so that a large cabin space can be taken. This advantage is particularly important in an FF vehicle having a small layout space.
(B) Since the distance between the support points (pivot points) on the vehicle body side is large, it is advantageous in terms of strength and the manufacturing error of alignment is relatively small.
(C) Since the structure is simple and the number of parts is small, it is advantageous in terms of cost and weight.
Due to the above merits, the strut-type front suspension is most often used as a front suspension for passenger cars.

  On the other hand, in-wheel motor vehicles, an in-wheel motor unit is developed separately from the suspension, and the arrangement of the motor and the speed reducer built in the unit case of the in-wheel motor unit is determined. When the unit case shape of the in-wheel motor unit is determined, a method of newly developing a suspension dedicated to the in-wheel motor unit is generally adopted. Because the development method that separates the in-wheel motor unit and the suspension is adopted in this way, when the in-wheel motor unit and the suspension are combined, a new problem is created, which is one of the causes for delaying the realization of the in-wheel motor vehicle. It has become.

  On the other hand, the inventor first paid attention to a strut type front suspension of an electric vehicle (actual vehicle) in which left and right front wheels are driven by a drive shaft. Then, when looking at the inner space of the tire wheel, it was found that the steering knuckle and the drive shaft boot occupied the inner space of the tire wheel as shown in FIG.

  Therefore, we examined whether it is possible to replace the in-wheel motor unit with the strut-type front suspension as it is in the space of the steering knuckle and drive shaft boot that occupies the inner space of the tire wheel. As a result of this study, it was concluded that the current space has a larger volume than expected and can be replaced with an in-wheel motor unit. Then, after solving various problems to be overcome when replacing the in-wheel motor unit, the in-wheel motor driving apparatus A of the first embodiment has been completed.

  In other words, the in-wheel motor drive device A of the first embodiment has an in-wheel motor unit 1 arranged in the space inside the tire wheel 2 while using the existing strut type front suspension as it is, as shown in FIG. It is.

  As described above, since the strut type front suspension can be used as it is and can be replaced with the in-wheel motor unit 1, all the merits of the strut type suspension according to the above (A) to (C) can be enjoyed. And since it is possible to shift to an in-wheel motor vehicle without changing the layout design at least for an existing vehicle having a strut type front suspension, it is possible to promote the realization of the in-wheel motor vehicle. it can.

[In-wheel motor unit displacement action during full turning]
As described above, when the strut type front suspension is used as it is and replaced with the in-wheel motor unit 1, it is necessary to avoid interference between the in-wheel motor unit 1 and the side member 43 (vehicle body 4) during the steering operation. . Hereinafter, based on FIG. 8, the displacement action of the in-wheel motor unit 1 during full turning will be described.

  When the steering operation position is in the neutral position, the in-wheel motor unit 1 and the side member 43 (the vehicle body 4) are separated as shown by the solid line in FIG. When the vehicle is fully steered from the neutral position in the left-right direction, the in-wheel motor unit 1 and the side member 43 (vehicle body 4) are unidirectional in the left-right direction (see FIG. 8). Approach by turning 8). However, when the vehicle is fully steered in the other direction (left-handed direction in FIG. 8) in the left-right direction, the in-wheel motor unit 1 and the side member 43 (vehicle body 4) as shown by the phantom line (tire wheel 2 ″) in FIG. And are far away from the neutral position.

  Thus, even in the fully steered state, a gap is secured between the in-wheel motor unit 1 and the side member 43 (vehicle body 4) as shown by the phantom line in FIG. This is because the virtual kingpin axis KP passes through a substantially intermediate position of the motor generator 5 built in the motor case 11 as shown in FIG. Therefore, even if the in-wheel motor unit 1 touches around the virtual kingpin axis KP as a central axis, the protrusion to the side member 43 (vehicle body 4) side is suppressed. The reason why the in-wheel motor unit 1 is approached by steering in one direction in the left-right direction (clockwise direction in FIG. 8) is that the unit case 10 is located in one direction side in the vehicle front-rear direction from the central axis CL of the tire wheel 2. Because of the offset arrangement.

  As described above, when the strut type front suspension is used as it is and replaced with the in-wheel motor unit 1, the in-wheel motor unit 1 and the side member 43 (vehicle body 4) do not interfere with each other even in a fully steered state to the left and right. I was able to confirm.

[Transverse link displacement during full rebound]
As described above, when the strut type front suspension is used as it is and replaced with the in-wheel motor unit 1, it is necessary to avoid the interference between the in-wheel motor unit 1 and the transverse link 33 at the time of full rebound. Hereinafter, based on FIG. 9, the displacement action of the transverse link 33 at the time of full rebound will be described.

  In a normal state on a flat road, the in-wheel motor unit 1 and the transverse link 33 are in a positional relationship maintaining a predetermined interval as shown by the solid line characteristics in FIG. When traveling on uneven roads, the distance between the in-wheel motor unit 1 and the transverse link 33 is wider than that in the normal state in a bound state or a full bound state where the suspension is contracted.

  However, when the suspension is in a rebound state in which the suspension extends, the distance between the in-wheel motor unit 1 and the transverse link 33 becomes narrower than the distance in the normal state. In the full rebound state, the positional relationship between the in-wheel motor unit 1 and the transverse link 33 is closest as shown by the phantom line in FIG. However, a gap is secured between the in-wheel motor unit 1 and the transverse link 33 as shown by the phantom line in FIG. This is because the first reduction gear ratio by the first reduction gear train 61 is made larger than the second reduction gear ratio by the second reduction gear train 62, so that the bottom height position BL of the unit case 10 is set at the transverse link 33. By being arranged at a height position away from the unit case support point P2.

  As described above, when the strut type front suspension is used as it is and replaced with the in-wheel motor unit 1, it is possible to confirm that the in-wheel motor unit 1 and the transverse link 33 do not interfere even when the full rebound state is obtained. did it.

[Characteristics of in-wheel motor drive]
In the first embodiment, the strut suspension 3 has the lower end portion of the strut 31 attached to the upper position of the unit case 10. The in-wheel motor unit 1 has the motor generator 5 arranged outside the vehicle in the axle direction with respect to the attachment position of the strut 31, and the reduction gear mechanism 6 is arranged in the axle direction with respect to the attachment position of the strut 31. It is placed inside the vehicle on the opposite side.

  That is, when the motor generator 5 and the reduction gear mechanism 6 are arranged in the case space of the unit case 10, attention is paid to the attachment position of the strut 31 attached to the unit case 10 in the strut suspension 3.

  Therefore, the motor generator 5 is disposed outside the vehicle in the axle direction with the mounting position of the strut 31 as a reference position. For this reason, when determining the axial length of the motor generator 5, it is not restricted by the reduction gear mechanism 6, and can be extended in the axial direction to the limit position of the brake rotor 87 fixed to the tire wheel 2, for example. It is. Therefore, the desired motor output is ensured by taking the axial length of the motor generator 5 without being restricted by the reduction gear mechanism 6.

  On the other hand, the reduction gear mechanism 6 is disposed inside the vehicle on the opposite side of the motor generator 5 with respect to the strut attachment position in the axle direction with the attachment position of the strut 31 as a reference position. For this reason, when determining the amount of protrusion of the unit case 10 from the strut 31 to the inside of the vehicle, for example, the first reduction gear train 61 and the second reduction gear train 62 are arranged by effectively using the narrow space in the case interior space. Is possible. Therefore, the case protrusion amount of the unit case 10 toward the inside of the vehicle is suppressed to be small, and interference with the vehicle body 4 and the adjacent link member is avoided.

In the first embodiment, a part of the reduction gear mechanism 6 is arranged in a lower region of the strut that overlaps with the strut 31 in the axle direction.
For example, the entire reduction gear mechanism 6 can be disposed on the vehicle inner side than the strut 31, but in this case, the axial length of the unit case 10 is increased.
On the other hand, an increase in the axial length of the unit case 10 can be suppressed by overlapping a part of the reduction gear mechanism 6 with the strut 31 in the axle direction.

In the first embodiment, the reduction gear mechanism 6 is a two-stage reduction gear that includes a first reduction gear train 61 and a second reduction gear train 62.
That is, the reduction ratio between the motor shaft 51 and the wheel drive shaft 21 is determined by the product of the first reduction ratio of the first reduction gear train 61 and the second reduction ratio of the second reduction gear train 62.
Therefore, since a large reduction ratio is possible as the reduction ratio of the reduction gear mechanism 6, the small-diameter type motor generator 5 with high rotation and low torque can be used.

In the first embodiment, in the unit case 10, the lower case position and the front suspension member 42 are connected by the transverse link 33. The reduction gear is a reduction gear mechanism 6 in which the first reduction gear is the first reduction gear train 61 and the second reduction gear is the second reduction gear train 62. The reduction gear mechanism 6 makes the first reduction ratio by the first reduction gear train 61 larger than the second reduction ratio by the second reduction gear train 62.
That is, the second reduction ratio by the second reduction gear train 62 is made smaller than the first reduction ratio by the first reduction gear train 61. For this reason, the size of the wheel drive shaft gear 66 that is the output side gear of the second reduction gear train 62 can be suppressed. As a result, as shown in FIG. 6, the bottom surface height position BL of the unit case 10 becomes a height position away from the unit case support point P2 of the transverse link 33.
Accordingly, even when the suspension is fully rebounded, interference between the unit case 10 and the transverse link 33 is avoided.

In the first embodiment, the first reduction gear train 61 is arranged in a region on the opposite side of the motor generator 5 with the strut 31 sandwiched in the axle direction. The second reduction gear train 62 is disposed in the lower region of the strut 31.
That is, since the strut 31 is arranged at a position coinciding with the second reduction gear train 62 in the axle direction, the lower end portion of the strut 31 is embedded to the inside of the unit case 10 as shown in FIGS. Space to be arranged in the state is secured. That is, even if the lower end portion of the strut 31 is in the embedded state, it does not interfere with the first idler shaft gear 64 and the motor generator 5. For this reason, it becomes possible to attach the in-wheel motor unit 1 to the steering knuckle part using the existing strut suspension as it is.
Therefore, the in-wheel motor drive device A equipped with the in-wheel motor unit 1 is configured by replacement using an existing strut suspension.

In the first embodiment, the motor generator 5 has a motor shaft 51 parallel to the wheel drive shaft 21. A knuckle arm 15 to which a steering mechanism tie rod 86 is connected is provided on the unit case 10. The motor generator 5 is disposed in a region opposite to the tie rod coupling portion 96 of the knuckle arm 15 with the wheel drive shaft 21 sandwiched in the direction orthogonal to the axle.
In other words, the tie rod connecting portion 96 is disposed in an empty space region formed away from the motor generator 5 in the vehicle front-rear direction. For this reason, the motor generator 5 can determine the motor outer diameter within the radial range by the inner diameter of the tire wheel 2 and the outer diameter of the wheel drive shaft 21 without being restricted by the radial length by the tie rod coupling portion 96. it can.
Therefore, a desired motor output can be ensured by taking the length of the motor outer diameter of the motor generator 5 without being restricted by the tie rod connecting portion 96.

In the first embodiment, the tire wheel 2 has a brake rotor 87 fixed to a position adjacent to the unit case 10 in the axle direction. A brake caliper 93 that clamps the brake rotor 87 is provided in the unit case 10. The brake caliper 93 is disposed in a circumferential region between the tie rod connecting portion 96 of the knuckle arm 15 and the motor generator 5 in the circumferential direction around the wheel drive shaft 21.
That is, the brake caliper 93 is arranged in an empty space region formed in the circumferential direction between the tie rod connecting portion 96 and the motor generator 5 without securing a dedicated space in the axle direction.
Accordingly, interference between the unit case 10 and the tie rod connecting portion 96 and the brake caliper 93 is avoided without increasing the length of the unit case 10 in the axle direction.

Next, the effect will be described.
In the in-wheel motor drive device A of the first embodiment, the effects listed below can be obtained.

(1) The in-wheel motor drive device A includes an in-wheel motor unit 1 and a strut suspension 3.
The in-wheel motor unit 1 has a motor (motor generator 5) and a reduction gear (deceleration gear mechanism 6) arranged in a case inner space of a unit case 10 arranged in an inner space portion of the tire wheel 2.
The strut suspension 3 uses a strut 31 that supports a force acting in the vertical direction of the vehicle, and suspends an unsprung member including the in-wheel motor unit 1 on the vehicle body 4.
In this in-wheel motor drive A, the strut suspension 3 attaches the lower end portion of the strut 31 to the upper position of the unit case 10.
The in-wheel motor unit 1 arranges a motor (motor generator 5) on the vehicle outer side than the attachment position of the strut 31 in the axle direction. The speed reducer (speed reduction gear mechanism 6) is disposed inside the vehicle on the opposite side of the motor (motor generator 5) with respect to the mounting position of the strut 31 in the axle direction (FIG. 5).
Therefore, when the motor (motor generator 5) and the reduction gear (reduction gear mechanism 6) are arranged in the case space of the unit case 10, the desired motor output is avoided while avoiding interference with the vehicle body 4 and the adjacent link member. Can be secured.

(2) A part of the reduction gear (reduction gear mechanism 6) is arranged in the lower region of the strut that overlaps the strut 31 in the axle direction (FIG. 5).
Therefore, in addition to the effect of (1), an increase in the axial length of the unit case 10 can be suppressed by overlapping a part of the reduction gear (the reduction gear mechanism 6) with the strut 31 in the axle direction.

(3) The reduction gear (reduction gear mechanism 6) is a two-stage reduction gear including a first reduction gear (first reduction gear train 61) and a second reduction gear (second reduction gear train 62) (FIG. 5).
For this reason, in addition to the effect of (2), since a large reduction ratio is possible, a small-diameter type motor (motor generator 5) with high rotation and low torque can be used.

(4) In the unit case 10, the lower position of the case and the vehicle body 4 (front suspension member 42) are connected by a transverse link 33.
The reduction gear is a reduction gear mechanism 6 in which the first reduction gear is the first reduction gear train 61 and the second reduction gear is the second reduction gear train 62.
The reduction gear mechanism 6 makes the first reduction ratio by the first reduction gear train 61 larger than the second reduction ratio by the second reduction gear train 62 (FIG. 6).
For this reason, in addition to the effect of (3), even when the suspension is fully rebounded, interference between the unit case 10 and the transverse link 33 can be avoided.

(5) The first reduction gear train 61 is disposed in a region on the opposite side of the motor (motor generator 5) with the strut 31 sandwiched in the axle direction.
The second reduction gear train 62 is disposed in the lower region of the strut 31 (FIG. 6).
For this reason, in addition to the effect of (4), the in-wheel motor drive device A equipped with the in-wheel motor unit 1 can be configured by replacing the existing strut suspension.

(6) The motor (motor generator 5) has a motor shaft 51 parallel to the wheel drive shaft 21.
A knuckle arm 15 to which a steering mechanism tie rod 86 is connected is provided on the unit case 10.
The motor (motor generator 5) is arranged in a region opposite to the tie rod coupling portion 96 of the knuckle arm 15 with the wheel drive shaft 21 in the direction orthogonal to the axle (FIG. 6).
For this reason, in addition to the effects (1) to (5), a desired motor output can be ensured by taking the length of the motor outer diameter of the motor (motor generator 5) without being restricted by the tie rod connecting portion 96. be able to.

(7) The tire wheel 2 has a brake rotor 87 fixed to a position adjacent to the unit case 10 in the axle direction.
A brake caliper 93 that clamps the brake rotor 87 is provided in the unit case 10.
The brake caliper 93 is arranged in a circumferential region between the tie rod connecting portion 96 of the knuckle arm 15 and the motor (motor generator 5) in the circumferential direction around the wheel drive shaft 21 (FIG. 6).
For this reason, in addition to the effects (1) to (6), interference between the unit case 10 and the tie rod connecting portion 96 and the brake caliper 93 can be avoided without increasing the length of the unit case 10 in the axle direction. .

  As described above, the in-wheel motor drive device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and each claim of the claims Design changes and additions are allowed without departing from the gist of the invention.

  In the first embodiment, an example in which the lower end portion of the strut 31 is attached to the upper position of the unit case 10 in an embedded state is shown. However, the form of attaching the lower end portion of the strut to the upper position of the unit case is not limited to the embedded state, and for example, it may be attached via an attachment flange provided in the unit case.

  In the first embodiment, an example in which a part of the reduction gear mechanism 6 (second reduction gear train 62) is arranged in the lower region of the strut that overlaps the strut 31 in the axle direction is shown. However, an example in which the entire reduction gear mechanism is arranged at a position that does not overlap with the strut in the axle direction may be used. Moreover, the example which arrange | positions all the reduction gear mechanisms in the strut lower area | region which overlaps with a strut in an axle direction may be sufficient.

  In the first embodiment, an example in which the reduction gear mechanism 6 is a two-stage reduction gear including the first reduction gear train 61 and the second reduction gear train 62 is shown. However, the reduction gear mechanism may be a one-stage reduction gear or a three-stage reduction gear or more. Further, instead of the reduction gear train, a planetary gear may be used, or a combination of the reduction gear train and the planetary gear may be used.

  In 1st Example, the example of the tie rod 86 arrange | positioned in the position of the vehicle rear side rather than the unit case 10 was shown as a tie rod. However, the tie rod may be an example in which the unit case is disposed at a position ahead of the vehicle relative to the unit case by replacing the unit case in the vehicle longitudinal direction.

  In the first embodiment, an example in which the in-wheel motor driving device A equipped with the in-wheel motor unit 1 is configured by replacing an existing strut type front suspension is shown. However, an in-wheel motor drive device equipped with an in-wheel motor unit may be one that does not use an existing suspension as long as it is combined with a strut suspension having struts. For example, a strut suspension with improved specifications may be used according to the required suspension performance such as wheel alignment, or a dedicated strut suspension may be used for the in-wheel motor unit.

  In the first embodiment, an example in which the in-wheel motor driving device of the present invention is applied to the left and right front wheels of an electric vehicle has been described. However, the in-wheel motor drive device of the present invention can be applied to the left and right rear wheels of an electric vehicle, or can be applied to all the wheels of an electric vehicle.

A In-wheel motor drive device 1 In-wheel motor unit 10 Unit case 15 Knuckle arm 2 Tire wheel 21 Wheel drive shaft 3 Strut suspension 31 Strut 32 Coil spring 33 Transverse link 4 Car body 5 Motor generator (motor)
51 Motor shaft 6 Reduction gear mechanism (reduction gear)
61 First reduction gear train (first reduction gear)
62 Second reduction gear train (second reduction gear)
86 Tie rod 87 Brake rotor 93 Brake caliper 96 Tie rod connecting part

Claims (7)

An in-wheel motor unit in which a motor and a speed reducer are disposed in a case inner space of a unit case disposed in an inner space portion of the tire wheel;
A strut suspension that uses a strut that supports a force acting in the vehicle vertical direction and suspends an unsprung member including the in-wheel motor unit on a vehicle body,
In-wheel motor drive device comprising:
The strut suspension, the lower end portion of the strut is attached to the upper position of the unit case,
In the in-wheel motor unit, the motor is disposed outside the strut attachment position in the axle direction, and the speed reducer is opposite to the motor in the axle direction with respect to the strut attachment position. An in-wheel motor drive device characterized by being disposed inside the vehicle. In the in-wheel motor drive device according to claim 1,
An in-wheel motor drive device, wherein a part of the speed reducer is arranged in a lower region of a strut that overlaps with the strut in an axle direction. In the in-wheel motor drive device according to claim 2,
The in-wheel motor drive device, wherein the reduction gear is a two-stage reduction gear including a first reduction gear and a second reduction gear. In the in-wheel motor drive device according to claim 3,
In the unit case, the lower part of the case and the vehicle body are connected by a transverse link,
The reduction gear is a reduction gear mechanism in which the first reduction gear is a first reduction gear train and the second reduction gear is a second reduction gear train,
The in-wheel motor drive device characterized in that the reduction gear mechanism makes a first reduction ratio by the first reduction gear train larger than a second reduction ratio by the second reduction gear train. In the in-wheel motor drive device according to claim 4,
The first reduction gear train is disposed in a region opposite to the motor across the strut in the axle direction;
The in-wheel motor drive device, wherein the second reduction gear train is disposed in a lower region of the strut. In the in-wheel motor drive device according to any one of claims 1 to 5,
The motor has a motor shaft parallel to the wheel drive shaft,
The unit case is provided with a knuckle arm to which a tie rod of a steering mechanism is connected,
The in-wheel motor drive device according to claim 1, wherein the motor is disposed in a region opposite to the tie rod coupling portion of the knuckle arm with the wheel drive shaft sandwiched in a direction orthogonal to the axle. In the in-wheel motor drive device according to any one of claims 1 to 6,
The tire wheel has a brake rotor fixed to a position adjacent to the unit case in the axle direction,
A brake caliper that clamps the brake rotor is provided in the unit case,
The in-wheel motor drive device according to claim 1, wherein the brake caliper is disposed in a circumferential region between the motor and the tie rod coupling portion of the knuckle arm in a circumferential direction around the wheel drive shaft.