JP2010137806A - Vehicle body rear structure provided with electric rear wheel drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body rear structure provided with an electric rear wheel drive device capable of suitably supporting an electric motor, a speed-reduction gear unit and a differential gear unit while they can be assembled while suppressing an influence of a stress concentration and certainly transmitting a drive force of the electric motor to a rear wheel in the vehicle provided with a suspension device having a plurality of lateral arms. <P>SOLUTION: While the electric motor 71, the speed-reduction gear unit 72 and the differential gear unit 73 are arranged in one row in an order from a vehicle front side to a vehicle rear side so that they are not overlapped in a plan view of the vehicle and overlapped in a vertical direction in a front view of the vehicle, input and output shafts 71a-73a are arranged so that they are approximately coincident with one another in a vehicle longitudinal direction. A coupling 75 is provided between the electric motor 71 and the speed-reduction gear unit 72, and front and rear sides are supported by front and rear lateral members 4F, 4R. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle body rear structure in which a sub-frame that forms a mounting base of a plurality of suspension lateral arms is disposed at a lower portion of a rear side frame, and more particularly to an electric rear wheel drive device having an electric motor.

  2. Description of the Related Art Conventionally, as a method of driving a rear wheel of a vehicle, a so-called electric type using a rotational driving force of an electric motor is known as described in Patent Document 1 below (see Patent Document 1).

  Thus, when the rear wheel drive system is an electric type, the rear wheel drive device includes an electric motor, a reduction gear unit that increases the torque by reducing the rotation speed of the output shaft of the electric motor, and a differential gear. What has a unit as a basic component is used.

  In the following Patent Document 1, when a rear wheel drive device is arranged, it is arranged in parallel with a rear suspension device for rear wheel suspension at the lower part of the rear portion of the vehicle body.

  In Patent Document 1 described below, a so-called coupled beam torsion beam suspension provided with a cross beam extending in the vehicle width direction to connect the left and right trailing arms is employed as a rear suspension device.

  In this case, by adopting a torsion beam suspension as the rear suspension device, the cross beam mainly extends in the vehicle width direction below the vehicle body floor at the lower part of the vehicle body rear part. For this reason, it is possible to secure an installation space for the rear wheel drive device in the lower part of the rear part of the vehicle body.

  Incidentally, as other suspension devices for suspending the wheels, for example, there is one in which a wheel support is supported by a plurality of suspension lateral arms.

In order to mount the rear suspension device having such a configuration on a vehicle, it is necessary to attach the rear suspension device to the vehicle body via a dedicated frame member disposed at the lower part of the rear portion of the vehicle body. In the following Patent Document 2, as a frame member that forms a mounting base of the lateral arm, left and right portions extending in the vehicle front-rear direction at both sides in the vehicle width direction, and lateral (cross) members before and after extending in the vehicle width direction A subframe is disclosed in which a frame is combined in a substantially frame shape.
JP 2005-96676 A JP 2007-83908 A

  Here, in the case where the rear suspension device having a plurality of lateral arms as described above is arranged at the rear part of the vehicle body, the electric rear wheel drive device is arranged in parallel at the lower part of the rear part of the vehicle body as in the above-mentioned Patent Document 1. Can be considered.

  However, in this case, the plurality of suspension lateral arms are disposed at the rear part of the vehicle body, and further, each member of the subframe is disposed across the front, rear, left and right, so that the rear wheel drive device is disposed. There is a risk of interference with the lateral arm and the subframe, and it is difficult to secure a space for arranging the rear wheel drive device.

  Therefore, the electric motor, the reduction gear unit, and the differential gear unit, which are the components of the rear wheel drive device, are stacked in the vertical direction so as to overlap in a plan view of the vehicle, and are unitized. It is also conceivable that a configuration in which interference between the rear wheel drive device and the lateral arm and interference between the rear wheel drive device and the sub-frame are avoided by being housed in the central region in the width direction.

  However, in this case, the vehicle type is set to a high vehicle height and is limited to a vehicle that can secure the height below the floor by raising the floor of the vehicle body floor. There is a drawback that the juxtaposition of the device and the rear wheel drive device cannot be realized.

  Therefore, as in the rear wheel drive device 507 shown in FIG. 19, the electric motor 571, the reduction gear unit 572, and the differential gear unit 573 are not overlapped in this order in the vehicle plan view from the vehicle front side to the vehicle rear side. The input / output shafts 507a for transmitting the output of the electric motor 571 to the differential gear unit 573 may be arranged so as to substantially coincide with the vehicle front-rear direction. .

  However, with such a configuration, when the rear wheel drive device 507 is operated, the electric motor 571 rotates the input / output shaft 507a around the X axis as shown by the thick arrow α in the figure, so that the electric motor 571 side Then, a reaction force α ′ (indicated by a thick arrow in the figure) due to this rotational drive acts, while the drive shaft 508 rotates around the Y axis as indicated by a thick arrow β in the figure, whereby a differential gear unit 573 is obtained. On the side, there is a problem that a reaction force β ′ due to the rotation of the rear wheel acts.

  As described above, when the vehicle travels, forces in different directions act on the rear wheel drive device 507 before and after the rear wheel drive device 507, so that a large stress concentration occurs in the intermediate portion. For this reason, when the rear wheel drive device 507 is configured as a single rigid body containing the electric motor 571, the reduction gear unit 572, and the differential gear unit 573 in one casing, the casing is stress-concentrated. Since it is necessary to make it strong to withstand, and an excessive increase in weight is expected due to thickening and the like, it becomes substantially difficult.

  On the other hand, when the electric motor 571, the reduction gear unit 572, and the differential gear unit 573 are separately arranged without being integrated, the input / output shaft 507a that transmits the driving force among them is particularly illustrated in FIG. The force indicated by the middle thick arrow β ′ acts, and these are bent into, for example, a mountain shape when viewed from the side of the vehicle (windup phenomenon).

  In this case, the input / output shaft 507a has a declination and eccentricity, which makes it difficult to transmit the driving force of the electric motor 571 to the rear wheels.

  Further, when the rear wheel drive device 507 described above is disposed at the lower part of the rear part of the vehicle body, the reaction force accompanying the driving of the electric motor 571 described above or the reaction force acting on the differential gear unit 572 side when the rear wheel rotates. Therefore, it is necessary to support the rear wheel drive device 507 appropriately against the reaction force in order to prevent the vibration generated by the vehicle from being input to the vehicle body side such as the passenger compartment.

  The present invention is provided with a suspension device having a plurality of lateral arms, and it is possible to assemble an electric motor, a reduction gear unit, and a differential gear unit while suppressing the influence of stress concentration, and appropriately supporting this. Another object of the present invention is to provide a vehicle body rear structure including an electric rear wheel drive device that can transmit the driving force of the electric motor to the rear wheels without fail.

  The rear structure of the vehicle body equipped with the electric rear wheel drive device according to the present invention has a plurality of suspension lateral arm mounting bases at the bottom of a pair of left and right rear side frames extending forward and backward inside the left and right rear wheel house. Meanwhile, the subframe extending in the vehicle width direction is fastened and fixed, while the electric motor, the reduction gear unit that reduces the rotational speed of the output shaft of the electric motor and increases the torque, and the output of the reduction gear unit A rear wheel drive device having a differential gear unit that changes the direction of the drive shaft of the rear wheel to a direction in which the drive shaft extends, and the sub-frame includes a front lateral member that connects the left and right parts at the front part, and a rear part at the rear part. A rear lateral member that connects the left and right parts, and in the rear wheel drive device, from the vehicle front side to the vehicle rear side. In order of the electric motor, the reduction gear unit, and the differential gear unit, these are arranged in a row so as to overlap in the vertical direction in the vehicle front view without overlapping in the vehicle plan view, and the output shaft of the electric motor; The input shaft of the differential gear unit that receives the output from the reduction gear unit is arranged so as to substantially coincide with the vehicle front-rear direction, and the rear wheel drive device is between the electric motor and the reduction gear unit, Or a coupling for transmitting rotational force while absorbing the declination and eccentricity formed between the input / output shafts between the reduction gear unit and the differential gear unit, and the front and rear laterals of the subframe. It is supported by the members.

According to this configuration, by providing the coupling between the electric motor and the reduction gear unit or between the reduction gear unit and the differential gear unit, the electric motor can be suppressed while suppressing the influence of stress concentration in the rear wheel drive device. It is possible to assemble a reduction gear unit and a differential gear unit. Then, by absorbing the declination and decentration formed by the input / output shafts by the coupling, the driving force of the electric motor can be reliably transmitted to the rear wheels.
Further, by supporting the front and rear portions of the rear wheel drive device by the front and rear lateral members, the rear wheel drive device can be appropriately supported before and after the coupling, and the reaction force accompanying the drive of the electric motor can be reduced. Further, it is possible to prevent the vibration generated by the reaction force acting on the differential gear unit side during the rotation of the rear wheel from being transmitted to the vehicle body side such as the passenger compartment.

  In one embodiment of the present invention, the rear wheel drive device is supported by the front lateral member at the front side from the coupling and supported by the rear lateral member at the rear side from the coupling.

  According to this configuration, the rear wheel drive device can be stably supported without a load being biased to either before or after the coupling.

  In one embodiment of the present invention, the front lateral member has a front projecting portion whose central portion is bent and projected forward in the vehicle plan view, and the front projecting portion of the rear wheel drive device is provided at the front projecting portion. The front side is supported.

  The subframe originally has high rigidity to support the rear suspension device. According to this configuration, the front projecting portion of the subframe can be firmly supported while avoiding interference with the rear wheel drive device.

  In one embodiment of the present invention, the rear wheel drive device includes a rear wheel power plant frame that extends in the vehicle front-rear direction and restricts relative displacement before and after the coupling, with the coupling as a boundary. The side on which the differential gear unit is disposed and the lateral member are connected by the power plant frame for the rear wheels.

According to this configuration, by controlling the relative displacement before and after the coupling by the rear wheel power plant frame, the windup phenomenon of the differential gear unit when the rear wheel rotates with respect to the other side when the coupling is a boundary ( Vertical swinging phenomenon) can be suppressed. For this reason, the responsiveness of the rear-wheel drive with respect to the rotational drive of an electric motor can be improved.
Further, by connecting the rear wheel power plant frame to the lateral member, it is possible to prevent the influence of vibration on the differential gear unit side from being exerted on the other side.

  In one embodiment of the present invention, an electric motor is disposed on the front side of the coupling of the rear wheel drive device, and at least two places are supported by the front lateral member, while the rear wheel drive is performed. On the rear side of the coupling of the apparatus, the differential gear unit is disposed, and at least two portions of the differential gear unit are supported by the rear lateral member, and the front lateral is planted by the rear wheel power plant frame. The member and the rear side of the coupling are connected.

According to this configuration, since the front side of the coupling is supported at two locations, the behavior of the electric motor side trying to rotate around a predetermined axis due to the rotational drive of the electric motor is effective at both side positions. Can be blocked.
Furthermore, since the rear side of the coupling is supported at a total of three locations by the rear lateral member and the rear wheel power plant frame, the front portion of the differential gear unit tends to lift due to the rotation of the rear wheel. The vibration can be reliably suppressed by supporting the vicinity of the rotating shaft at the time and effectively preventing the rear wheel power plant frame from lifting up with a long moment arm.

  In an embodiment of the present invention, an electric motor is disposed on the front side of the coupling of the rear wheel drive device, and a base portion on the output shaft side of the electric motor is formed on the front lateral member. The differential gear unit is disposed on the rear side of the coupling of the rear wheel drive device, and at least two positions of the differential gear unit are at the rear lateral side. It is supported by a member, and the front lateral member and the rear side of the coupling are connected by the rear wheel power plant frame.

According to this configuration, the base of the electric motor can be attached to and detached from the motor fixing portion, so that not only the electric motor can be easily attached and detached when the electric motor fails, but also the vehicle driving environment in various markets around the world. Accordingly, the electric motor can be easily changed to one having a different specification for production.
Furthermore, since the rear side of the coupling is supported at a total of three locations by the rear lateral member and the rear wheel power plant frame, the front portion of the differential gear unit tends to lift due to the rotation of the rear wheel. The vibration can be reliably suppressed by supporting the vicinity of the rotating shaft at the time and effectively preventing the rear wheel power plant frame from lifting up with a long moment arm.

According to the present invention, by providing the coupling between the electric motor and the reduction gear unit, or between the reduction gear unit and the differential gear unit, the electric motor can be suppressed while suppressing the influence of stress concentration in the rear wheel drive device. It is possible to assemble a reduction gear unit and a differential gear unit. Then, by absorbing the declination and decentration formed by the input / output shafts by the coupling, the driving force of the electric motor can be reliably transmitted to the rear wheels.
Further, by supporting the front and rear portions of the rear wheel drive device by the front and rear lateral members, the rear wheel drive device can be appropriately supported before and after the coupling, and the reaction force accompanying the drive of the electric motor can be reduced. Further, it is possible to prevent the vibration generated by the reaction force acting on the differential gear unit side during the rotation of the rear wheel from being transmitted to the vehicle body side such as the passenger compartment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
First, the first embodiment shown in FIGS. 1 to 8 will be described. FIG. 1 is a bottom view showing a vehicle body rear structure according to the first embodiment of the present invention, FIG. 2 is a perspective view showing a support structure of a rear wheel drive device, and FIG. It is a schematic plan view which shows a support structure notionally.

  As shown in FIG. 1, in the vehicle body rear structure according to the present embodiment, the rear side frames 2 and 2 (vehicle body rigid members) are provided on the inner side of the wheel houses 1 and 1 for the left and right rear wheels indicated by a two-dot chain line in the drawing. A closed cross section extending in the front-rear direction of the vehicle is formed between the rear side frame 2 and the rear floor 3 constituting the floor panel at the rear of the vehicle body.

  Further, as shown in FIG. 1, a sub frame 4 (so-called suspension cross member) is attached to the lower part of the pair of left and right rear side frames 2 and 2.

  The subframe 4 includes left and right side cross members 4S and 4S extending in the front-rear direction of the vehicle, and a front lateral member 4F extending in the vehicle width direction at the front and connecting the front portions of the side cross members 4S and 4S. And a rear frame 4R that extends in the vehicle width direction at the rear portion and connects the rear portions of the side cross members 4S and 4S to each other in a substantially frame shape when viewed from the bottom. The left and right rear wheels are suspended through an upper arm 51, a lower arm 52, and a toe control link 53 that form a suspension lateral arm of the rear suspension device 5 described later.

  Here, the rear suspension device 5 includes a wheel support 54 that rotatably supports a rear wheel, and a trailing arm 55 that extends from the wheel support 54 in the front direction of the vehicle and has a front end swingably attached to the rear side frame 2. And.

  A plurality of arm attachment portions are formed on the wheel support 54, and the above-described upper arm 51, lower arm 52, and toe control link 53 end portions in the vehicle width direction are attached to the arm attachment portions.

  A mounting portion for the upper arm 51 is provided on the upper side of the wheel support 54, and an outer end portion in the vehicle width direction of the upper arm 51 extending in the vehicle width direction is swingably supported by the mounting portion. Although not shown in FIG. 1, the inner end of the upper arm 51 in the vehicle width direction is swingably attached to the side cross member 4 </ b> S of the subframe 4.

  An attachment portion for the lower arm 52 is provided below the wheel support 54, and an outer end portion in the vehicle width direction of the lower arm 52 extending in the vehicle width direction is supported by the attachment portion so as to be swingable. . An inner end in the vehicle width direction of the lower arm 52 is swingably attached to the rear lateral member 4R of the subframe 4.

  The wheel support 54 is provided with a mounting portion for a toe control link 53, and an outer end portion in the vehicle width direction of the toe control link 53 extending in the vehicle width direction is swingably supported by the mounting portion. Yes. The vehicle width direction inner side end portion of the toe control link 53 is swingably attached to the front lateral member 4F of the sub frame 4. The toe control link 53 has a role of adjusting the degree of opening of the left and right wheels 2.

  In the rear suspension device 5, the toe control link 53 is arranged in front of the upper arm 51 and the lower arm 52 in a plan view, and is arranged in an E shape in which three links are arranged substantially in parallel in a plan view.

  A member denoted by reference numeral 56 in FIG. 1 is a damper, and an attachment portion for attaching the damper 56 is formed below the wheel support 54.

  By the way, as described above, the sub-frame 4 forms the vehicle body side mounting base of the upper arm 51, the lower arm 52, and the toe control link 53, and is separated from the front and rear at the bottom of the vehicle body, specifically, the left and right rear side frames 2, 2. It is fastened and fixed through bush mounts 6, 6,... Shown in FIGS.

  As shown in FIG. 2, the above-described bush mount 6 includes an outer cylinder 6a, a sleeve 6b, and a rubber member 6c interposed between the both 6a and 6b. The lateral members 4F and 4R of the sub-frame 4 are supported by the rear side frames 2 and 2 via a plurality of bush mounts 6 and 6 through the sleeve 6b of the mount 6 and tightening.

  In the present embodiment, as described above, the sub-frame 4 is formed in a substantially frame shape to form the closed region A1 surrounded by the front and rear lateral members 4F and 4R and the side members 4S and 4S. In this closed region A1, a rear wheel drive device 7 for rotating the rear wheels independently is disposed.

  The rear wheel drive device 7 is a deceleration that increases the torque by reducing the rotational speed of the electric motor 71 that mainly serves as a drive source for the rear wheels and the output shaft 71a (see FIGS. 1 and 3) when the electric motor 7 is driven. An electric drive device having a gear unit 72 and a differential gear unit (hereinafter abbreviated as a differential gear unit) 73 for converting the direction of output from the reduction gear unit 72 to the direction in which the drive shaft 8 of the rear wheel extends. It is.

  Among these, the connector C is attached to one side of the electric motor 71. By connecting a wire harness WH (see FIG. 2) forming a power supply line and a signal line to the connector C, the electric motor 71 is connected to a power source and a motor control device (not shown) mounted on the vehicle, and is driven to rotate. It becomes possible.

  A fuel tank 9 is disposed below the rear floor 3 immediately before the subframe 4 and the rear wheel drive device 7. In addition, a tunnel portion 91 having a bottom surface protruding upward from the other portion is formed in the central portion so as to extend in the vehicle front-rear direction. In the recessed space of the tunnel portion 91, the exhaust pipe 10 is formed. Is arranged.

  The exhaust pipe 10 extends from the front of the vehicle to the rear of the vehicle through the tunnel 91 and is connected to a main silencer 11 as a silencer at the downstream end thereof. The pipe member connected to the main silencer 11 is a tail pipe 12.

  In the present embodiment, the propeller shaft as a transmission member that transmits the driving force of the engine (not shown) to the rear wheels is omitted by the rear wheel drive device 7 described above, and thus the tunnel portion 91 of the fuel tank 9 is omitted. It is possible to secure a large installation space for the exhaust pipe 10 in FIG.

  Here, the configuration of the rear wheel drive device 7 and the support structure thereof will be described in detail.

  As shown in FIGS. 1 to 3, the rear wheel drive device 7 includes an electric motor 71, a reduction gear unit 72, and a differential gear unit 73 that are not overlapped in the vehicle plan view from the vehicle front side to the rear side. Are arranged in a line in the vehicle front-rear direction (at the center in the vehicle width direction) so as to overlap in the vertical direction when viewed from the front of the vehicle, and the output shaft 71a of the electric motor 71, the output shaft 72a of the reduction gear unit 72, and The input shaft 73a of the differential gear unit 73 that receives the output of the output shaft 72a is arranged so as to be directed in the vehicle front-rear direction (substantially coincide with the vehicle front-rear direction).

  Further, flange portions 71b and 72b are provided on the rear end side of the electric motor 71 and the front end side of the reduction gear unit 72, respectively, and these are overlapped and fastened to each other. Thereby, the electric motor 71 and the reduction gear unit 72 are integrated, and the front unit part 74 is comprised.

  Further, behind the front unit 74, the output shaft 72 a and the input shaft 73 a are connected via a coupling 75 between the reduction gear unit 72 and the differential gear unit 73.

  Moreover, in this embodiment, as shown in FIGS. 1-3, the front lateral member 4F of the sub-frame 4 has the front protrusion part 41 which bent and protruded toward the vehicle front by planar view in the center part. The front unit located in front of the coupling 75 is disposed so that the front end portion thereof is close to the front side portion 41 a of the front protruding portion 41 and is surrounded by the front protruding portion 41.

  The forward projecting portion 41 is located in front of the fastening portion of the sub-frame 4 (front lateral member 4F) to the rear side frames 2 and 2 and enters the rearward recessed portion 92 formed at the center rear portion of the fuel tank 9. Are arranged as follows.

  FIG. 4 is an enlarged plan view showing the front unit part, and FIG. 5 is an exploded perspective view for explaining the attachment of the front unit part to the front lateral member. In the rear wheel drive device 7, on the front side of the coupling 75, as shown in FIGS. A bush mount 76 is disposed at the tip of the formed tip. The front projecting portion 41 of the front lateral member 4F is formed with left and right side portions 41b and 41b extending in the vehicle front-rear direction on the left and right sides thereof along the rear wheel drive device 7, and includes a bush mount 76. A support protrusion 41c is formed to protrude inward in the vehicle width direction.

  The bush mount 76 includes an outer cylinder 76a, a sleeve 76b, and a rubber member 76c interposed between the both 76a and 76b. As shown in FIG. 5, a fastening member such as a bolt B1 is attached to the bush mount. By passing through the sleeve 76b 76 and the fastening hole 41d of the support protrusion 41c and tightening, the left and right two portions of the front unit portion 74 where the electric motor 71 is disposed are connected to the front protrusion 41 via the bush mount 76. The left and right sides 41b are supported.

  FIG. 6 is an exploded perspective view for explaining attachment of the differential gear unit to the rear lateral member. In the rear wheel drive device 7, on the rear side of the coupling 75, the upper surface portion of the differential gear unit 73 is fastened to the support arm 77 as shown in FIGS. 1, 2, and 6 by a fastening member such as a bolt B <b> 2. At the same time, it is supported by the rear lateral member 4R via bush mounts 77A and 77A formed at the left and right ends of the support arm 77.

  The bush mount 77A includes an outer cylinder 77a, a sleeve 77b, and a rubber member 77c interposed between the both 77a and 77b, and a fastening member such as a bolt B3 is connected to the bush mount as shown in FIG. The 77A sleeve 77b and the two fastening holes 13a and 13a of the support bracket 13 attached to the center portion in the vehicle width direction of the rear lateral member 4R are passed through and tightened, so that the left and right two places on the upper surface of the differential gear unit 73 are The rear lateral member 4R is supported via the bush mount 77A and the support bracket 13.

  Further, at the front end portion of the differential gear unit 73, a base portion of a rear wheel power plant frame (hereinafter abbreviated as PPF for rear wheels) 78 that extends in the vehicle front-rear direction and has a relatively large bending rigidity. 78a is attached, and the differential gear unit 73 is connected to and supported by the front lateral member 4F via the rear wheel PPF 78 as shown in FIGS. 1 to 3 and FIG.

  Specifically, as shown in FIG. 7, a bush mount 78A including an outer cylinder 78b, a sleeve 78c, and a rubber member 78d interposed between the two 78b and 78c at the front end of the PPF 78 for rear wheels. As shown in FIGS. 1, 2, and 7, a fastening hole 41f is formed on one side (here, the right side) of the left and right side portion 41b of the front protruding portion 41 while protruding toward the front of the vehicle. A support protrusion 41e is provided.

  Then, as shown in FIG. 7, a fastening member such as a bolt B4 is passed through the sleeve 78c of the bush mount 78A and the fastening hole 41f of the support protrusion 41e, and tightened, whereby the front end portion of the differential gear unit 73 is The left and right side portions 41b are supported via the mount 78A.

  The support position of the differential gear unit 73 by the bush mount 78A is set in the vicinity of the support position of the front unit 74 by the bush mount 76, as shown in FIGS.

  Thus, in the vehicle body rear structure according to the present embodiment, the front lateral member 4F has the front protruding portion 41 at the center thereof, and the electric motor 71, the reduction gear unit 72, from the vehicle front side toward the rear side, The differential gear unit 73 includes a rear wheel drive device 7 arranged in a line at the center in the vehicle width direction so as not to overlap in the vehicle plan view but to overlap in the vertical direction in the vehicle front view. The front portion of the rear wheel drive device 7 is supported by the front protrusion 41 of the front lateral member 4F, and the rear portion is supported by the rear lateral member 4R. The rear wheel drive device 7 includes the front lateral member 4F and the rear lateral member 4F. The rear lateral member 4R is disposed so as to extend in the front-rear direction.

  Here, in the rear wheel drive device 7, the electric motor 71, the reduction gear unit 72, and the differential gear unit 73 are not overlapped in the vehicle plan view but overlapped in the vehicle front-rear direction (vehicle width direction). By arranging in a row (in the central portion), it is possible to avoid interference with a plurality of lateral arms (upper arm 51, lower arm 52, toe control link 53) while suppressing the vertical width of rear wheel drive device 7. It can be arranged at the lower part of the rear part of the vehicle body regardless of the vehicle height.

  Furthermore, the subframe 4 originally has high rigidity so as to support the rear suspension device 5. Accordingly, the front protrusion 41 of the subframe 4 can be firmly supported while avoiding interference with the rear wheel drive device 7.

  For this reason, while electrically supporting the electric rear wheel drive device 7, the suspension device 5 having the lateral arm (the upper arm 51, the lower arm 52, and the toe control link 53) is juxtaposed without causing interference. be able to.

  Further, the input shaft 71a of the electric motor 71 and the output shaft 73a of the differential gear unit 73 are arranged so as to be directed in the vehicle front-rear direction, and the left and right sides 41b, 41b extend to the left and right along the rear wheel drive device 7. With this configuration, the front portion of the rear wheel drive device 7 extending in the vehicle front-rear direction can be supported without using any member other than the subframe 4.

  Further, by forming a rearward recessed portion 92 in the center rear portion of the fuel tank 9 into which the front projecting portion 41 positioned in front of the fastening portion to the rear side frames 2 and 2 of the sub frame 4 (front lateral member 4F) is inserted. While it becomes possible to avoid interference between the rear wheel drive device 7 extending in the vehicle longitudinal direction and the fuel tank 9, the left and right portions of the rearward recessed portion 92 relatively protrude to the vicinity of the subframe 4 at the rear of the vehicle. By doing so, the capacity of the fuel tank 9 can be secured.

  In the present embodiment, as shown in FIGS. 1 to 4 and 8, a coupling 75 is provided between the reduction gear unit 72 and the differential gear unit 73. As a result, it is possible to assemble the electric motor 71, the reduction gear unit 72, and the differential gear unit 73 while suppressing the influence of stress concentration in the rear wheel drive device 7, and the input / output shafts 71a, 72a, 73a form each other. By absorbing the declination and eccentricity by the coupling 75, the driving force of the electric motor 71 can be reliably transmitted to the rear wheels.

  Further, as in the present embodiment, the front and rear portions of the rear wheel drive device 7 are supported by the front and rear lateral members 4F and 4R, thereby appropriately supporting the rear wheel drive device 7 before and after the coupling 75. be able to. For this reason, it is possible to prevent the reaction force accompanying the driving of the electric motor 71 and the vibration generated by the reaction force acting on the differential gear unit 73 side when the rear wheel rotates, from being transmitted to the vehicle body side such as the passenger compartment.

  And by supporting the sub-frame 4 via the bush mounts 6, 6,..., It is possible to reliably prevent the vibration described above from being transmitted to the vehicle body side.

  In addition, the front unit 74 on the front side of the coupling 75 is supported on the front lateral member 4F, and the differential gear unit 73 on the rear side of the coupling 75 is supported on the rear lateral member 4R, whereby a load is applied to either the front or rear. The rear wheel drive device 7 can be stably supported without being biased.

  When the coupling 75 is considered as a boundary, the differential gear unit 73 side and the front lateral member 4F are connected by the rear wheel PPF 78, so that the front wheel front and rear of the coupling 75 can be obtained by the large bending rigidity of the rear wheel PPF 78. And the windup phenomenon (vertical swinging phenomenon) of the differential gear unit 73 during the rotation of the rear wheel relative to the front unit 74 can be suppressed. For this reason, the responsiveness of the rear-wheel drive with respect to the rotational drive of the electric motor 71 can be improved.

  Further, by connecting the PPF 78 for the rear wheel to the front lateral member 4F, it is possible to prevent the influence of the vibration on the differential gear unit 73 side from being given to the front unit portion 74.

  In addition, as conceptually shown in FIG. 3 in particular, the front unit 74 on the front side of the coupling 75 is supported at two locations by the bush mount 76, so that these two support points should be set appropriately. Thus, the behavior of the front unit 74 attempting to rotate around the X axis due to the rotational drive of the electric motor 71 can be effectively prevented at both side positions.

  Furthermore, in this embodiment, as specifically shown conceptually in FIG. 3, the differential gear unit 73 side on the rear side of the coupling 75 is added to the two locations of the bush mounts 77A and 77A, and a total of 3 by the PPF 78 for the rear wheels. We support in place. The bush mounts 77A and 77A support the vicinity of the rotation shaft when the front part of the differential gear unit 73 is about to lift due to the rotation of the rear wheel, and the behavior of the rear wheel PPF 78 is about to lift this behavior. By effectively blocking with a long moment arm, the vibration can be reliably suppressed.

  In addition, about each bush mount 6, 76, 77A, 78A, the axial direction can be set to an appropriate direction according to the direction which absorbs a vibration, or the direction where force acts.

(Second Embodiment)
Next, a second embodiment shown in FIGS. 9 to 12 will be described. FIG. 9 is a perspective view showing a support structure of a rear wheel drive device according to the second embodiment, FIG. 10 is a schematic plan view conceptually showing the structure and support structure of the rear wheel drive device, and FIG. 11 is an electric motor. FIG. 12 is an exploded perspective view for explaining attachment of the electric motor to the front lateral member. 9 to 12, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the rear wheel drive device 107 according to the present embodiment, as shown in FIGS. 9 and 10, only the electric motor 171 is disposed on the front side of the coupling 175, while on the rear side of the coupling 175, deceleration is performed. The gear unit 172 and the differential gear unit 173 are connected to form a rear unit portion 174. In the present embodiment, a coupling 175 is disposed between the electric motor 171 and the reduction gear unit 172, specifically, between the output shaft 171a and the input shaft 172a.

  In order to suppress the wind-up phenomenon of the differential gear unit 173 when the rear wheel rotates with respect to the electric motor 171, the upper surface portion of the reduction gear unit 172 of the rear unit portion 174 is attached to the rear wheel PPF 178 by bolts B5 and B5. As shown in FIGS. 9 and 10, the rear unit unit 174 is coupled to and supported by the front lateral member 4 </ b> F via the rear wheel PPF 178.

  As shown in FIG. 9, the rear wheel PPF 178 also has a bush mount 178A as shown in FIG. 9, which is formed on the left and right side portions 41b of the front protruding portion 41 in the same manner as the rear wheel PPF 78. It is fastened to the support protrusion 41e.

  Further, on the front side of the coupling 175, as shown in FIG. 11, arm portions 171c extending outward in the vehicle width direction are attached to both ends of the electric motor 171 in the vehicle width direction. A bush mount 176 provided with 176a, a sleeve 176b, and a rubber member 176c is disposed.

  Then, as shown in FIG. 12, a fastening member such as a bolt B6 is passed through the sleeve 176b of the bush mount 176 and the fastening hole 41d of the support protrusion 41c, and tightened so that the left and right portions of the electric motor 171 are bushed. It is supported on the left and right side portions 41 b of the front projecting portion 41 via the mount 176.

  Also in the present embodiment, the front unit located in front of the coupling 175 is disposed so that the front end portion thereof is close to the front side portion 41 a of the front protruding portion 41 and is surrounded by the front protruding portion 41. ing.

  On the other hand, on the rear side of the coupling 175, as in the first embodiment, as shown in FIGS. 9 and 10, the upper surface portion of the differential gear unit 173 is fastened to the support arm 77, and the bush mount 77A of the support arm 77, It is supported by the rear lateral member 4R through 77A.

  Even in such a configuration, the rear wheel drive device 107 and the rear suspension device 5 interfere with each other while the rear wheel drive device 107 is firmly supported by the subframe 4 as in the first embodiment described above. They can be installed side by side without being generated.

  Further, by providing a coupling 175 between the electric motor 171 and the reduction gear unit 172, the electric motor 171, the reduction gear unit 172, and the differential gear unit 173 are assembled while suppressing the influence of stress concentration in the rear wheel drive device 107. It becomes possible to do. The declination and eccentricity between the output shaft 171a and the input shafts 172a and 173a (see FIG. 10) can be absorbed by the coupling 175, and the driving force of the electric motor 171 can be reliably transmitted to the rear wheels. become.

  In addition, as conceptually shown in FIG. 10 in particular, the electric motor 171 on the front side of the coupling 175 is supported at two locations by the bush mount 176, so that these two support points can be set appropriately. It is possible to effectively prevent the behavior of the electric motor 171 from rotating around the X axis at the both side positions due to the rotational drive.

  Further, the rear unit portion 174 on the rear side of the coupling 175 is supported at a total of three locations by the PPF 178 for rear wheels in addition to the two locations of the bush mounts 77A and 77A. The bush mounts 77A and 77A support the vicinity of the rotation shaft when the front portion of the differential gear unit 173 is lifted due to the rotation of the rear wheel, and the rear wheel PPF 178 behaves to be lifted. By effectively blocking with a long moment arm, the vibration can be reliably suppressed.

  Other functions and effects are the same as those of the first embodiment described above.

(Third embodiment)
Incidentally, in each of the above-described embodiments, the electric motors 71 and 171 are arranged close to the front side 41a of the front projecting portion 41 from the rear, but the present invention is not necessarily limited thereto. For example, as in the subframe 204 shown in FIGS. 13 and 14, the front side portion 241 a of the front projecting portion 241 formed on the front lateral member 204 F extends left and right below the electric motor 71 and the reduction gear unit 72. The electric motor 71 may extend beyond the front side 241a and extend forward. In FIG. 13 and FIG. 14, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the case of this embodiment, the front protrusion 241 is formed so that the left and right parts 241b and 241b are inclined downwardly as shown in the figure.

  With such a configuration, the front protrusion 241 is interposed between the rear wheel drive device 7 (electric motor 71) and the road surface, so that the rear wheel drive device 7 (electric motor 71) interferes with the road surface. Can be prevented. In addition, since the forward protrusion amount of the front protrusion 241 can be suppressed, the front lateral member 204F can be reduced in weight, that is, the subframe 204 can be reduced in weight.

  Other functions and effects are the same as those of the first embodiment described above.

  Moreover, each site | part 241c, 241e shown in FIG. 13 respond | corresponds to the support protrusion 41c, 41e in 1st Embodiment, The effect | action etc. are substantially the same.

(Fourth embodiment)
Further, in each of the above-described embodiments, the front side of the couplings 75 and 175 is supported by the front protrusions 41 and 241 via the bush mounts 76 and 176, but the present invention is not necessarily limited to this. For example, an electric motor 371 on the front side of the coupling 375 is formed on the front lateral member 304F of the subframe 304 as in the rear wheel drive device 307 shown in FIGS. The front side of the rear wheel drive device 307 may be supported by directly fastening and fixing to the front projecting portion 341. 15 to 18, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, a motor fixing portion 341a is set by forming a fastening hole 341g and a through hole 341h as shown in FIG. 16 at the central front side portion of the front protruding portion 341. The motor fixing portion 341a fixes the base of the electric motor 371 on the output shaft 371a side, so that the electric motor 371 is supported in a state of protruding further forward from the front protruding portion 341 as shown. Yes.

  Specifically, a flange portion 371b having a plurality of fastening holes 371d formed at the base portion of the electric motor 371 is provided. As shown in FIGS. 15 to 17, fastening members B7, B7,. The electric motor 371 can be fixed to the motor fixing portion 341a by passing through and tightening the fastening hole 371d of the electric motor 371 and the fastening hole 341g of the motor fixing portion 341a.

  In this embodiment, the output shaft 371a (see FIGS. 16 and 17) of the electric motor 371, the output shaft 372a of the reduction gear unit 372, and the input shaft 373a (see FIG. 16) of the differential gear unit 73 are arranged in the vehicle longitudinal direction. In the state where the electric motor 371 is fixed to the motor fixing portion 341a, the output shaft 371a extends rearward through the through hole 341h. As a result, the output shaft 371a can be connected to the rear reduction gear unit 372.

  Further, it is possible to remove the electric motor 371 from the front projecting portion 341 by removing the fastening of the fastening member B7, that is, the base portion of the electric motor 371 is detachable from the motor fixing portion 341a. ing. Thereby, not only can the attachment / detachment and replacement at the time of failure of the electric motor be facilitated, but also the electric motor 371 can be easily changed to one having a different specification according to the vehicle traveling environment in the markets around the world.

  For example, in the case of a car (model) exported to a country with good road conditions, for example, it is sufficient to drive the rear wheel assistively when starting a snowy road, so a small electric motor with a small torque may be adopted. However, in the case of a car that is exported to a country with many unpaved roads, sometimes the rear wheels are driven to escape from the mud road, so it is necessary to adopt a large electric motor with a large torque to meet this.

  The configuration of the present embodiment in which the electric motor 371 can be replaced can be realized only by complicating the mounting process of the electric motor when a vehicle of a plurality of destination countries having different specifications of the electric motor is produced on one production line. There is an effect that it can respond to.

  By the way, as shown in FIGS. 15 and 18, the front protrusion 341 is provided with a support protrusion 341 e corresponding to the support protrusion 41 e in the vicinity of the motor fixing part 341 a, and the differential gear unit 373 It is connected to and supported by the front lateral member 304F via the wheel PPF 378.

  A base portion 378a of a rear wheel PPF 378 is attached to the front end portion of the differential gear unit 373 so as to suppress a wind-up phenomenon when the rear wheel rotates with respect to the electric motor 371 and the reduction gear unit 372. A bush mount 378A including an outer cylinder 378b, a sleeve 378c, and a rubber member 378d is disposed. As shown in FIG. 18, a fastening member such as a bolt B8 is connected to the sleeve 378b of the bush mount 378A and the support protrusion. The front end portion of the differential gear unit 373 is supported by the front projecting portion 341 via the bush mount 378A by passing through and tightening the fastening hole 341f of the portion 341e.

  Other functions and effects are the same as those of the first embodiment described above.

(Other embodiments)
In each of the above-described embodiments, the case where a plurality of lateral arms are arranged in an E shape in plan view has been described as the rear suspension device 5, but the present invention is not necessarily limited thereto. Alternatively, the rear suspension device may have a plurality of lateral arms, and the sub-frame forming the attachment base may be disposed at the lower part of the rear portion of the vehicle body.

In correspondence between the configuration of the present invention and the above-described embodiment,
The plurality of suspension lateral arms of the present invention correspond to the upper arm 51, the lower arm 52, and the toe control link 53,
Similarly,
The left and right parts correspond to the side cross member 4S,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The bottom view which shows the vehicle body rear part structure which concerns on 1st Embodiment of this invention. The perspective view which shows the support structure of a rear-wheel drive device. The schematic plan view which shows notionally the structure and support structure of a rear-wheel drive device. The top view which expands and shows a front unit part. The disassembled perspective view for demonstrating the attachment to the front lateral member of a front unit part. The disassembled perspective view for demonstrating the attachment to the rear part lateral member of a differential gear unit. The disassembled perspective view for demonstrating the attachment to the front lateral member of the power plant frame for rear wheels. The figure for demonstrating the behavior of the rear-wheel drive device at the time of rotation of a rear wheel. The perspective view which shows the support structure of the rear-wheel drive device which concerns on 2nd Embodiment of this invention. The schematic plan view which shows notionally the structure and support structure of a rear-wheel drive device. The top view which expands and shows an electric motor. The disassembled perspective view for demonstrating the attachment to the front lateral member of an electric motor. The perspective view which shows the support structure of the rear-wheel drive device which concerns on 3rd Embodiment of this invention. The schematic plan view which shows notionally the structure and support structure of a rear-wheel drive device. The perspective view which shows the support structure of the rear-wheel drive device which concerns on 4th Embodiment of this invention. The schematic plan view which shows notionally the structure and support structure of a rear-wheel drive device. The disassembled perspective view for demonstrating the attachment to the front protrusion part of an electric motor. The disassembled perspective view for demonstrating the attachment to the rear lateral member of a differential gear unit, and the attachment to the front lateral member of the power plant frame for rear wheels. The figure for demonstrating the behavior of the rear-wheel drive device at the time of rotation of a rear wheel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel house 2 ... Rear side frame 4, 204, 304 ... Sub-frame 4F, 204F, 304F ... Front lateral member 4R ... Rear lateral member 4S ... Side cross member 7, 107, 307 ... Rear-wheel drive device 41,241 , 341 ... Forward projecting part 51 ... Upper arm 52 ... Lower arm 53 ... Toe control links 71, 171, 371 ... Electric motors 71a, 171a, 371a ... Output shafts 72, 172, 372 ... Reduction gear units 73, 173, 373 ... Differential Gear units 73a, 173a, 373a ... input shafts 75, 175, 375 ... coupling 78, 178, 378 ... rear wheel power plant frame 341a ... motor fixing portion

Claims (6)

A sub-frame extending in the vehicle width direction is fastened and fixed to the lower part of a pair of left and right rear side frames extending forward and backward inside the left and right rear wheel house while forming a mounting base for a plurality of suspension lateral arms. ,
An electric motor;
A reduction gear unit that increases the torque by reducing the rotational speed of the output shaft of the electric motor;
A rear wheel drive device having a differential gear unit that converts the output direction of the reduction gear unit into a drive shaft extending direction of the rear wheel,
The subframe has a front lateral member that connects the left and right parts at the front part, and a rear lateral member that connects the left and right parts at the rear part,
In the rear wheel drive device, the electric motor, the reduction gear unit, and the differential gear unit are arranged in this order from the front side of the vehicle toward the rear side of the vehicle in the vertical direction in the front view of the vehicle without overlapping in the plan view of the vehicle. While being arranged in a row to overlap,
The output shaft of the electric motor and the input shaft of the differential gear unit that receives the output from the reduction gear unit are arranged so as to substantially coincide with the vehicle longitudinal direction,
The rear wheel drive device absorbs a declination and an eccentricity between the input and output shafts between the electric motor and the reduction gear unit or between the reduction gear unit and the differential gear unit. With a coupling that transmits rotational force,
A vehicle body rear structure including an electric rear wheel drive device supported by front and rear lateral members of the subframe. In the rear wheel drive device, the front side of the coupling is supported by the front lateral member,
The vehicle body rear part structure provided with the electrically driven rear-wheel drive device according to claim 1, wherein a rear side of the coupling is supported by the rear lateral member. The front lateral member has a front projecting portion whose central portion is bent and projected forward in the vehicle plan view,
The vehicle body rear part structure equipped with the electric rear wheel drive device according to claim 2, wherein a front side of the rear wheel drive device is supported by the front protrusion. A rear-wheel power plant frame that extends in the vehicle front-rear direction and regulates the relative displacement before and after the coupling;
The side where the differential gear unit of the said rear-wheel drive device is arrange | positioned on the said coupling, and the said lateral member are connected with the said power plant frame for rear wheels. A vehicle body rear structure comprising the electric rear wheel drive device according to claim. On the front side of the coupling of the rear wheel drive device, an electric motor is disposed,
While at least two locations are supported by the front lateral member,
On the rear side of the coupling of the rear wheel drive device, the differential gear unit is disposed, and at least two locations of the differential gear unit are supported by the rear lateral member,
The vehicle body rear part structure provided with the electric rear-wheel drive device of Claim 4 with which the said front lateral member and the back side of the said coupling were connected by the said power plant frame for rear wheels. On the front side of the coupling of the rear wheel drive device, an electric motor is disposed,
While the base on the output shaft side of the electric motor is detachably fixed by a motor fixing portion formed on the front lateral member,
On the rear side of the coupling of the rear wheel drive device, the differential gear unit is disposed, and at least two locations of the differential gear unit are supported by the rear lateral member,
The vehicle body rear part structure provided with the electric rear-wheel drive device of Claim 4 with which the said front lateral member and the back side of the said coupling were connected by the said power plant frame for rear wheels.

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