JP2006264409A - Front suspension device of automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double wishbone type front suspension device capable of obtaining excellent vehicle kinetic performance and good ride quality without deteriorating anti-dive geometry. <P>SOLUTION: The front suspension device has an upper arm 4, an A type lower arm which is the A type lower arm 6 connected to a vehicle body at two places, and has a front arm part 6a extending substantially widthwise from the connecting part of the vehicle body front side with the vehicle body, and a rear arm part 6b extending widthwise outward and obliquely forward from the connecting part of the vehicle body rear side with the vehicle body, an elastic bush 25 which is provided on the connecting part of the vehicle body rear side of the lower arm so that the center line extends to the vertical direction of the vehicle body, a wheel support 8 rotatably supporting the wheel, and a shock absorber 10 having a lower arm connected to the lower end part so that the rear arm part of the lower arm is displaced to the upper part of the vehicle body by the reaction force of the shock absorber during braking. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a front suspension apparatus for an automobile, and more particularly to a front suspension apparatus for a double wishbone automobile.
About.

The double wishbone suspension is a suspension type that provides excellent vehicle motion performance, particularly excellent handling stability. In such a suspension, an elastic bush having increased compliance is provided at the connection portion of the suspension arm to the vehicle body so as to obtain good riding comfort. In this double wishbone suspension device, the lower end of the shock absorber is generally attached to the lower arm.
Here, Patent Document 1 discloses a suspension device in which an elastic bush provided so that an axis extends in the vertical direction of the vehicle body is provided in a vehicle body side connecting portion on the vehicle body rear side of the transverse link. Has been. In this strut suspension device, the lower end of the shock absorber is generally attached to a wheel support (wheel support member).

European Patent No. 0653320B1

  Here, in the double wishbone suspension device, by providing an elastic bush extending in the vertical direction of the vehicle body at the connecting portion on the vehicle body rear side of the lower arm, the compliance can be increased and good riding comfort can be obtained. However, when the axis of the elastic bush extends in the vertical direction of the vehicle body, the arm portion of the lower arm on the vehicle body rear side is easily displaced in the vertical direction.

  Conventionally, as shown in FIG. 7, for example, as shown in FIG. 7, the mounting position 106f of the shock absorber is such that the shock absorber mounting portion 106f is connected to the vehicle body front side connecting portion 126 and the wheel support connecting portion 106e. Is disposed on the axis A ′ connecting the two or more, and further rearward of the axis A ′, and the shock absorber itself is inclined with respect to the lower arm. Such a lower arm 106 includes an upward force that acts on the outer end 106e of the lower arm in the vehicle width direction from the tire via the wheel support, and a downward reaction force of the shock absorber that is applied to the mounting position 106f of the lower arm. However, due to the mounting position and the inclination direction of the shock absorber described above, the lower arm during braking is applied particularly when the downward reaction force of the shock absorber is applied to the rear side of the vehicle body from the axis A ′. A downward force is applied to the rear arm portion 106b of the vehicle body. When the elastic bush 125 extending in the vertical direction of the vehicle body is provided at the connecting portion 128 on the vehicle body rear side, the lower arm portion 106b on the vehicle body rear side is displaced to the vehicle body lower side.

  Here, in the double wishbone type suspension, each arm is arranged in consideration of pitching geometry. In particular, anti-dive geometry is considered in the front suspension. For example, as shown by a solid line in FIG. 5, the anti-dive geometry is inclined so that the upper arm (4) is lowered rearward in a side view (a line connecting two pivot shafts on the vehicle body side of the upper arm is inclined backward). At the same time, the lower arm (6) is tilted so as to be raised rearward in a side view (the line connecting the two pivot shafts on the vehicle body side of the lower arm is tilted forward), so that the braking force F applied to the tire 16 is increased. It acts as a force for pushing the vehicle body upward through the suspension arm. That is, the anti-dive geometry reduces the nose dive by generating a force that opposes the nose dive force due to the pitching of the vehicle body during braking.

  Therefore, as described above, when the lower arm portion (reference numeral 106b in FIG. 7) on the rear side of the vehicle body is displaced to the lower side of the vehicle body, as shown in FIG. The lower arm inclines toward the rear side as viewed from the side, which reduces the effect of the anti-dive geometry.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and is a double wish capable of obtaining excellent vehicle motion performance and good riding comfort without deteriorating the anti-dive geometry. The object is to provide a bone-type front suspension device.

In order to achieve the above object, the present invention is a front suspension device for a double wishbone type automobile, comprising an upper arm and an A-type lower arm connected to the vehicle body at two locations, the vehicle front side of the vehicle body. A lower arm having a front arm portion extending substantially in the vehicle width direction from the connecting portion on the side and a rear arm portion extending obliquely forward in the vehicle width direction outward from the connecting portion on the vehicle body rear side with the vehicle body, and the vehicle body rear side of the lower arm An elastic bush provided with a central axis extending in the vertical direction of the vehicle body at the connecting portion on the side, a wheel support connected to the upper arm and the lower arm to rotatably support the wheel, and an upper end portion connected to the vehicle body and the lower arm A shock absorber with a lower end connected thereto, and the rear arm portion of the lower arm is displaced upward by the reaction force of the shock absorber during braking. It is characterized by being configured to so that.
In the double wishbone suspension device according to the present invention configured as described above, the upper arm, the A-type lower arm, and the connecting portion on the vehicle body rear side of the lower arm are provided so that the central axis extends in the vertical direction of the vehicle body. Since it has an elastic bush, excellent vehicle motion performance and good riding comfort can be obtained. Furthermore, since the rear arm portion of the lower arm is configured to be displaced above the vehicle body by the reaction force of the shock absorber during braking, it is possible to prevent the anti-dive geometry of the front suspension from deteriorating. That is, in the anti-dive geometry, the lower arm is tilted so as to rise rearward in a side view, and such tilt can be prevented from being reduced by the reaction force of the shock absorber during braking. As a result, in the front suspension device according to the present invention, the anti-dive geometry is not deteriorated, and the anti-dive action by the anti-dive geometry can be obtained more effectively.

In the present invention, it is preferable that the axis of the shock absorber extends from the upper side to the lower side toward the vehicle body front side of the axis line connecting the connection portion of the lower arm to the vehicle body front side and the connection portion of the wheel support. Yes.
In the present invention configured as described above, the axis of the shock absorber extends from the upper side to the lower side toward the vehicle body front side of the axis line connecting the connection portion of the lower arm to the vehicle body front side and the connection portion of the wheel support. Sometimes, a moment force that tilts the lower arm toward the front of the vehicle body can be applied to the lower arm by the downward reaction force of the shock absorber (see, for example, moment M1 in FIG. 4). On the other hand, the elastic bushing of the connecting portion on the vehicle body rear side of the lower arm is provided so that the central axis extends in the vehicle body vertical direction, so the inner end in the vehicle width direction of the rear arm portion provided with the elastic bushing Is easily displaced upward in the vehicle body. Therefore, the rear arm portion of the lower arm can be displaced upward of the vehicle body by the reaction force of the shock absorber during braking, and as a result, the anti-dive geometry of the front suspension can be prevented from deteriorating.

In the present invention, it is preferable that the shock absorber is attached to the lower arm at the vehicle body front side of the axis line connecting the connecting portion of the lower arm on the vehicle body front side and the wheel support connecting portion.
In the present invention configured as described above, the lower end portion of the shock absorber is attached to the lower arm on the vehicle body front side of the axis line connecting the connection portion of the lower arm to the vehicle body front side and the connection portion of the wheel support. More reliably, a moment force that tilts the lower arm toward the front of the vehicle body by the downward reaction force of the shock absorber during braking can be applied to the lower arm, and the rear arm portion can be displaced upward of the vehicle body. As a result, deterioration of the anti-dive geometry of the front suspension can be prevented.

In the present invention, it is preferable that the shock absorber is attached to the lower arm on the vehicle body upper side of the axis line connecting the connecting portion of the lower arm at the vehicle body front side of the lower arm and the wheel support and the axis of the shock absorber. Is arranged so as to extend obliquely forward from the upper side to the lower side with respect to an axis connecting the connecting portion of the lower arm on the vehicle body front side and the connecting portion of the wheel support.
In the present invention configured as described above, the lower end portion of the shock absorber is attached to the lower arm on the vehicle body upper side of the axis line connecting the connecting portion of the lower arm on the vehicle body front side and the connecting portion of the wheel support. Since the axis extends obliquely forward and obliquely forward with respect to the axis connecting the connecting part of the lower arm body front side and the connecting part of the wheel support from the upper side to the lower side, the lower side of the shock absorber is more reliably applied during braking. A moment force that tilts the lower arm toward the front of the vehicle body by the reaction force can be applied to the lower arm, and the rear arm portion can be displaced upward of the vehicle body. As a result, deterioration of the anti-dive geometry of the front suspension can be prevented.

In the present invention, it is preferable that the steering gear unit is further fixed to a position in front of the vehicle body from the upper arm and the lower arm of the vehicle body, and the steering gear unit and the wheel extend obliquely forward from the steering gear unit outward in the vehicle width direction. A tie rod that connects the front end portion of the vehicle body of the support, and the elastic bush has two straight portions that extend along the outer peripheral portion and face each other, and these straight portions are in plan view, The line connecting them extends in an obliquely rearward direction outward in the vehicle width direction with respect to the longitudinal direction of the vehicle body, and the shock absorber is directed outward in the vehicle width direction from above to below. Are arranged to extend obliquely downward.
In the present invention configured as described above, a line connecting two straight portions provided on the elastic bush extends obliquely rearwardly outward in the vehicle width direction with respect to the vehicle longitudinal direction in plan view. Since the axis of the shock absorber extends diagonally downward from the top toward the outside in the vehicle width direction, the front suspension with the front-mounted steering gear unit suppresses toe-out during braking of the front wheels, The behavior of the vehicle can be stabilized. Here, when the tie rod extends obliquely forward in the vehicle width direction and is connected to the front end of the vehicle body of the wheel support, the front end of the vehicle body of the wheel support is the angle at which the braking force applied to the wheel during braking and the tie rod extend Due to this, it is displaced obliquely rearward in the vehicle width direction outward, and toe-out easily occurs. However, according to the present invention, due to the arrangement of the shock absorber described above, a force that is directed outward in the vehicle width direction is applied to the lower arm during braking, and when such a force is applied, the arrangement of the two straight portions described above is applied. The elastic bush is deformed obliquely backward in the vehicle width direction outward, and the rear arm portion is displaced obliquely backward in the vehicle width direction outward. Therefore, even if the front end of the vehicle body of the wheel support is displaced obliquely rearward, the lower arm connecting portion of the wheel support is also displaced obliquely rearward outward in the vehicle width direction, and toe-out during braking of the front wheels can be suppressed. I can do it. As described above, according to the present invention, it is possible to obtain excellent vehicle motion performance in which the behavior of the vehicle at the time of braking is stable while preventing the deterioration of the anti-dive geometry at the time of braking and suppressing the toe-out. .

  According to the double wishbone type front suspension device of the present invention, it is possible to obtain excellent vehicle motion performance and good riding comfort without deteriorating the anti-dive geometry.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the front suspension apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing a front suspension apparatus for an automobile according to an embodiment of the present invention.
A front suspension device 1 according to an embodiment of the present invention is attached to a suspension cross member 2 fixed to a vehicle body (not shown). The suspension cross member 2 includes a U-shaped front member 2a extending in the vehicle width direction and extending from both sides toward the rear of the vehicle body, and an upper member 2b extending upward fixed to both sides of the front member 2a in the vehicle width direction. The rear member 2c extends in the vehicle width direction behind the front member 2a, and both end portions thereof are fixed to the front member 2a.

  The front suspension device 1 is of a double wishbone type, and includes an upper arm 4 attached to the upper member 2b, a lower arm 6 attached to the front member 2a, a wheel support 8 attached to these arms 4 and 6, and a buffer. A device 10 is provided. The wheel support 8 supports the front wheel 16 (see FIG. 3), the brake disc 17 and the like so as to be rotatable. The shock absorber 10 includes a damper 12 and a coil spring 14, the upper ends of which are fixed to a vehicle body (not shown), and the lower end of the damper 12 is rotatably attached to the lower arm 6.

  Further, the front suspension device 1 includes a steering gear unit 16 fixed to the front member 2a so as to extend in the vehicle width direction on the front side of the suspension cross member 2, and extends outward from the steering gear unit 16 in the vehicle width direction. And a tie rod 18 attached to the wheel support 8. The steering gear unit 16 is a rack and pinion type or ball screw type steering device, and is adapted to steer the front wheels 16 via a tie rod 18.

Next, the configuration of the front suspension device 1 will be specifically described with reference to FIGS. FIG. 2 is a plan view of the right front wheel side of the front suspension device for a vehicle according to the embodiment of the present invention as viewed from above the vehicle body, and FIG. 3 shows the right front wheel side of the front suspension device for the vehicle according to the embodiment of the present invention. FIG. 4 is a front view seen from the front of the vehicle body, and FIG. 4 is a plan view showing a lower arm of the front suspension device of the automobile according to the embodiment of the present invention. Here, since the basic structure of the front suspension device of an automobile is the same on both the right front wheel side and the left front wheel side, here, description will be made mainly with reference to FIGS. 2 and 3 showing the right front wheel side.
First, the structure of each arm 4 and 6 and the structure of the connection between the vehicle body and the wheel support will be described. As shown in FIGS. 2 and 3, the upper arm 4 is an A-type arm having a front arm portion 4a and a rear arm portion 4b, and is attached to the upper member 2b of the suspension cross member 2 by two attachment portions 20, 22. It is attached. In these connecting portions 20 and 22, the vehicle width direction inner end portions 4 c and 4 d of the arm portions 4 a and 4 b are attached to the vehicle body side via a cylindrical elastic bush 24. These elastic bushes 24 are provided so as to have a central axis in the longitudinal direction of the vehicle body.

  Next, as shown in FIGS. 2 to 4, the lower arm 6 is an A-type arm having a front arm portion 6a extending substantially in the vehicle width direction and a rear arm portion 6b extending obliquely forward in the vehicle width direction outward. Yes, it is attached to the front member 2a of the suspension cross member 2 by two attachment portions 26, 28. In these connecting portions 26 and 28, the inner ends 6c and 6d in the vehicle width direction of the respective arm portions 6a and 6b are attached to the vehicle body side via cylindrical elastic bushes 24 and 25. In addition, in FIG. 3, illustration of the rear arm part 6b is abbreviate | omitted.

  The elastic bush 24 of the connecting portion 26 on the front side of the vehicle body is provided so as to have a central axis in the longitudinal direction of the vehicle body, while the elastic bush 25 of the connecting portion 28 on the rear side of the vehicle body has a central axis in the vertical direction of the vehicle body. Is provided. The bushes 24 and 25 provided on the lower arm 6 have large compliance in order to ensure riding comfort. On the other hand, in order to ensure maneuverability, the elastic bushing 24 of the connecting portion 26 on the front side of the vehicle body is relatively smaller in compliance than the elastic bushing 25 of the connecting portion 28 on the rear side of the vehicle body.

  As shown in FIGS. 2 and 3, the vehicle width direction outer ends 4 e and 6 e of the upper arm 4 and the lower arm 6 are attached to the wheel support 8. Specifically, the wheel support 8 includes an extension portion 8a for connecting an upper arm extending upward and an extension portion 8b for connecting a lower arm extending downward, and each of the arms 4 and 6 has an extension portion 8a. , 8b are attached to the upper end portion and the lower end portion via a ball joint 30.

Next, a configuration related to the arrangement of the shock absorber 10 and the connection with the lower arm 6 will be described.
As shown in FIGS. 2 to 4, the lower arm 6 is formed with a shock absorber connecting portion 6 f to which the lower end portion 10 b of the shock absorber 10 is connected. As shown in FIGS. 2 and 4, the shock absorber connecting portion 6f connects the connecting portion 26 to the vehicle body of the front arm portion 6a of the lower arm 6 and the connecting portion 6e to the wheel support 8 in a plan view. It is formed so as to be positioned on the front side of the vehicle body with respect to the axis A. The lower end portion of the shock absorber 10 is connected to the lower arm 6 on the front side of the vehicle body from the axis A by the shock absorber connecting portion 6f formed in this way.

  Further, as shown in FIG. 3, the shock absorber connecting portion 6f is formed so as to protrude upward of the vehicle body with respect to the axis A described above in a front view. The lower end portion of the shock absorber 10 is connected to the lower arm 6 on the vehicle body upper side from the axis A by the shock absorber connecting portion 6f formed in this way. Further, as shown in FIGS. 2 and 3, the shock absorber 10 is configured such that the position of the upper end portion 10a attached to the vehicle body is inward in the vehicle width direction with respect to the position of the lower end portion 10b, that is, the position of the shock absorber connection portion 6f. It is arrange | positioned so that it may become the side and the vehicle body front-back direction back side. In particular, as shown in FIG. 2, the axis B of the shock absorber 10 extends obliquely forward from the upper side to the lower side in a plan view and extends obliquely forward with respect to the above-described axis A of the lower arm 6.

In the front suspension device 1 configured as described above, the axis B from the upper end portion 10a of the shock absorber 10 toward the lower end portion 10b (6f) extends to the vehicle body front side of the above-described axis A of the lower arm 6. Yes. In this embodiment, as can be understood from the configuration shown in FIGS. 2 and 3, the axis B crosses the vehicle body upper side with respect to the axis A and crosses the vehicle body front side with respect to the axis A. Yes.
Moreover, as shown in FIG. 3, the axis B of the shock absorber 10 extends obliquely downward from the upper side toward the lower side in the vehicle width direction when viewed from the front.

  Next, the configuration of the tie rod 18 will be described. As shown in FIG. 2, the wheel support 8 includes a tie rod connecting extension portion (knuckle arm) 8c extending forward of the vehicle body, and an end portion 8d of the tie rod 18 in the vehicle width direction is provided at a distal end portion 8d of the extension portion 8c. Is attached. The inner end of the tie rod 18 in the vehicle width direction is attached to the steering gear unit 16.

  As shown in FIG. 2, the tie rod 18 extends obliquely forward in the vehicle width direction outward in a plan view, and has an inclination angle α with respect to the vehicle width direction. The inclination angle α establishes the Ackermann geometry of the front suspension device 1 so that the turning angle of the turning inner wheel is larger than the turning angle on the outer wheel side during steering. As shown in FIG. 3, the tie rod 18 extends obliquely upward outward in the vehicle width direction when viewed from the front, and has an inclination angle β with respect to the horizontal line. By this inclination angle β, the front suspension device 1 has a bump toe-in characteristic, and the bumped turning outer ring is prevented from moving toward the toe-out.

Next, the configuration of the elastic bush 25 of the connecting portion 28 on the vehicle body rear side of the lower arm 6 will be described with reference to FIG.
As shown in FIG. 4, the inner end 6d in the vehicle width direction of the lower arm 6 is formed in a cylindrical shape so as to have a central axis in the vertical direction of the vehicle body, and has a central axis in the vertical direction of the vehicle body on the inside thereof. The elastic bush 25 is press-fitted. A metal inner cylinder part 32 is bonded to the surface of the inner peripheral part of the elastic bush 25, and the inner cylinder part 32 is fixed to the vehicle body side, that is, the suspension cross member 2.

The elastic bush 25 is formed with two straight portions (soaking portions) 34 extending along the outer peripheral portion thereof. These straight portions 34 are through holes extending parallel to the central axis of the elastic bush 25. The portions provided with the straight portions 34 are less elastic than the other portions, that is, are easily bent. When the elastic bush 25 receives a force from the end 6d of the lower arm, the elastic bush 25 is on a line connecting the straight portions 34 and the central axis. It becomes easy to deform in the direction of.
Among these straight portions 34, the first straight portion 34a is inward in the vehicle width direction from the vehicle longitudinal axis C of the elastic bushing 25 (or a neutral surface extending through the central axis in the vehicle longitudinal direction) in plan view. And an area 25a on the front side of the vehicle body from the vehicle width direction axis D of the elastic bush 25 (or a neutral surface extending in the vehicle width direction passing through the center axis). In the present embodiment, the axis C coincides with the axis connecting the connecting portion 26 on the vehicle body front side of the lower arm 6 and the connecting portion 28 on the vehicle body rear side.

  The second curb portion 34b has a vehicle body longitudinal direction axis C (or a neutral surface extending in the vehicle longitudinal direction passing through the central axis) of the elastic bushing 25 in a plan view, and in a plan view. The elastic bush 25 is formed in a region 25b on the rear side of the vehicle body from the vehicle width direction axis D (or a neutral surface extending through the center axis in the vehicle width direction). The second straight part 34b is formed opposite to the first straight part 34A at a position symmetrical with respect to the central axis of the elastic bush 25.

  In the straight portions 34a and 34b, the intermediate portion in the longitudinal direction along the outer peripheral portion of the elastic bush 25 is located at a position of 25 to 35 degrees (angle γ in the figure) from the vehicle longitudinal axis C in plan view. It is formed so that In other words, the line connecting the central axis of the elastic bushing 25 and the intermediate portion in the longitudinal direction of the straight portions 34a and 34b is inclined at 25 to 35 degrees (angle γ) with respect to the longitudinal axis C of the vehicle body in plan view. As such, the straight portions 34a and 34b are formed. In the present embodiment, the angle γ is 30 degrees. Further, the straight portions 34a and 34b are formed such that one end portion in the longitudinal direction thereof is positioned at 0 to 5 degrees from the longitudinal axis C of the vehicle body, and is 0 degrees in this embodiment. The straight portions 34a and 34b are formed so that the longitudinal direction thereof extends in a direction substantially parallel to the direction in which the tie rod 18 extends. That is, the angle γ and the inclination angle α are substantially the same.

Next, the function and effect of the present embodiment will be described with reference to FIGS.
FIG. 5 is a conceptual diagram of the suspension device for explaining the anti-dive geometry of the front suspension and the displacement of the lower arm due to the reaction force of the shock absorber as viewed from the side in the vehicle width direction.
First, in the present embodiment, as shown in FIGS. 2 and 3, the shock absorber connecting portion 6 f is connected to the vehicle support portion 26 and the wheel support 8 of the front arm portion 6 a of the lower arm 6 in plan view. The lower end of the shock absorber 10 is connected to the lower arm 6 on the front side of the vehicle body with respect to the axis A. The lower end of the shock absorber 10 is formed on the front side of the vehicle body with respect to the axis A connecting the portion 6e. With such a configuration, the rear arm portion 6b of the lower arm 6 can be displaced upward in the vehicle body during braking.

Here, conventionally, for example, as shown in FIG. 7, the attachment position 106f of the shock absorber (indicated by the axis B ′) to the lower arm 106 is the connecting portion 126 (106c) on the vehicle body front side of the lower arm 106 and the wheel support. It was attached on the axis A ′ connecting the connecting portion 106e to (not shown) or at a position closer to the rear arm portion 106b than the axis A ′. Further, the shock absorber is oriented in substantially the same direction as the axis A ′, like the axis B ′.
In such a conventional configuration, particularly during braking, the upward force from the wheel applied to the connecting portion 106e via the wheel support and the downward reaction force of the shock absorber applied to the shock absorber mounting position 106f are A moment force as shown by the middle M2 is generated, and the rear arm portion 106b is displaced downward in the vehicle body, which may adversely affect the anti-dive geometry as described above.

  On the other hand, in the present embodiment, as shown in FIG. 4 in particular, the lower end portion of the shock absorber 10 is connected to the lower arm 6 on the front side of the vehicle body from the axis A. Join the lower arm 6 in front of A. Therefore, a moment force as indicated by M1 in the figure can be generated in the lower arm 6. In other words, the connecting portions 126 and 6e of the lower arm 6 are used as support points, and a downward reaction force of the shock absorber 10 is applied to the front side of the axis A connecting these support points. A moment force M1 is generated so as to tilt the lower arm 6 forward of the vehicle body. On the other hand, since the elastic bush 25 of the connecting portion 28 on the vehicle body rear side of the lower arm 6 is provided so that the axis thereof extends in the vehicle body vertical direction, the inner end portion 6d of the rear arm portion 6b receives the moment force M1. This makes it easier to displace the vehicle body upward. Therefore, as shown in FIG. 5, the rear arm portion 6b of the lower arm 6 is displaced upward in the vehicle body. As a result, the anti-dive geometry is prevented from deteriorating, or the anti-dive effect by the anti-dive geometry is further obtained. You can do that.

  Next, in the present embodiment, as shown in FIGS. 2 and 3, the shock absorber connecting portion 6 f is formed so as to protrude toward the vehicle body upper side with respect to the axis A described above when viewed from the front, and the lower end of the shock absorber 10. The part is connected to the lower arm 6 on the upper side of the vehicle body from the axis A. Further, the shock absorber 10 is arranged such that its axis B extends obliquely forward and obliquely with respect to the axis A of the lower arm 6 from above to below in plan view. Also with such a configuration, the rear arm portion 6b of the lower arm 6 can be displaced upward in the vehicle body during braking.

  That is, the lower end portion of the shock absorber 10 is connected to the lower arm 6 on the upper side of the vehicle body from the axis A, and the axis B is obliquely forward with respect to the axis A of the lower arm 6 from the upper end portion to the lower end portion of the shock absorber 10. Since it extends incline, the downward reaction force of the shock absorber 10 is applied to the lower arm 6 in the direction above the axis A and toward the front of the vehicle body. Accordingly, a moment force as indicated by M1 in FIG. 4 is generated in the lower arm 6 and the rear arm portion 6b of the lower arm 6 is moved upward in the vehicle body during braking as shown in FIG. Can be displaced. As a result, deterioration of the anti-dive geometry can be prevented, or the anti-dive effect by the anti-dive geometry can be obtained more.

Here, according to the above-described configuration, the lower end portion of the shock absorber 10 is connected to the lower arm 6 on the front side of the vehicle body from the axis A, so that the axis B of the shock absorber 10 is directed downward from above. The lower arm 6 can extend forward of the vehicle body with respect to the axis A of the lower arm 6.
Further, the lower end portion of the shock absorber 10 is connected to the lower arm 6 on the upper side of the vehicle body from the axis A, and the axis B is inclined with respect to the above-described axis A of the lower arm 6 from the upper end portion to the lower end portion of the shock absorber 10. Similarly, the axis B of the shock absorber 10 can extend from the upper end portion 10a toward the lower end portion (6f) toward the vehicle body front side with respect to the axis A of the lower arm 6 because it extends obliquely forward. . Furthermore, the axis B can cross the vehicle body upper side with respect to the axis A, and can cross the vehicle body front side with respect to the axis A.
Therefore, if the double wishbone suspension device is configured so as to obtain such a relative relationship between the axis A and the axis B, the above-described action, that is, the moment shown by M1 in FIG. By generating force, the rear arm portion 6b of the lower arm 6 can be displaced upward in the vehicle body.

Next, the operation and effect of the arrangement of the shock absorber 10 and the straight portion 34 will be described with reference to FIGS. 4 and 6. FIG. 6A is a conceptual diagram of the right front wheel side of the suspension device for explaining the toe-out displacement of the wheel support during braking, as viewed from above the vehicle body, and braking of the suspension arm, wheel support and tie rod according to the embodiment of the present invention. It is the conceptual diagram (b) which looked at the right front-wheel side of the suspension apparatus for demonstrating the displacement in time from the vehicle body upper direction.
In the present embodiment, the shock absorber 10 is disposed such that its axis B extends obliquely downward from the upper side toward the lower side in the vehicle width direction, and the straight portion 34 is provided on the elastic bush 25 of the connecting portion 28. By providing, toe-out at the time of braking of the front wheel 16 can be suppressed.

  Here, at the time of braking, the rotational moment force generated in the wheel support 8 by the braking force F (see FIG. 5) applied to the wheels 16 toward the rear of the vehicle body causes the elastic bushes 24 of the connecting portions 26 and 28 of the arms 4 and 6 to 25 is deformed. As a result, the upper arm 4 is displaced toward the front of the vehicle body and the lower arm 6 is displaced toward the rear of the vehicle body, and the wheel support 8 is rotationally displaced. With the rotational displacement of the wheel support 8 as described above, the distal end portion 8d of the extension portion (knuckle arm) 8c for connecting the tie rod is displaced downward and rearward of the vehicle body.

  That is, as indicated by phantom lines in FIGS. 6A and 6B, the inclination angle (α) of the tie rod 18 decreases due to the downward displacement of the tip 8d and the rear of the vehicle body, while the tie rod 18 Since the length of itself does not change, the front end portion 8d is displaced downward and on the rear side of the vehicle body, and is also displaced outward in the vehicle width direction. That is, due to the fact that the tie rod 18 is attached to the front end of the vehicle body of the wheel support 8 and that the tie rod 18 is inclined, as shown in FIG. The front wheels 16 move toward the toe-out direction, and the vehicle stability at the time of braking is lowered particularly during high-speed traveling.

In the present embodiment, the shock absorber 10 is disposed such that its axis B extends obliquely downward from the top toward the bottom and outward in the vehicle width direction. Accordingly, a force directed outward in the vehicle width direction is applied to the lower arm 6, and such force is further transmitted to the end 6 d of the lower arm 6. The elastic bush 25 tends to deform outward in the vehicle width direction by the force directed outward in the vehicle width direction transmitted to the end 6d and the force received from the inner cylinder portion of the elastic bush 25 on the vehicle body side. To do.
Further, the elastic bush 25 tends to deform toward the rear of the vehicle body in response to the displacement force of the lower arm 6 toward the rear side of the vehicle body due to the braking force F described above.

On the other hand, in the plan view, the two straight portions 34a and 34b are connected to the line C connecting the connecting portion 26 on the vehicle body front side of the lower arm 6 and the connecting portion 28 on the vehicle body rear side. Since the elastic bushing 25 is disposed so as to be inclined obliquely rearwardly outward in the width direction, the elastic bushing 25 is easily deformed in the diagonally rearward direction outward in the vehicle width direction.
Accordingly, the end 6d of the lower arm 6 on the vehicle body rear side is displaced in the diagonally rearward direction outward in the vehicle width direction as indicated by E in FIG.
As a result, the end 6d is displaced in the direction as shown in FIG. 6B, and along with such displacement, the connecting portion 6e of the lower arm 6 to the wheel support 8 is displaced rearward in the vehicle body direction. At the same time, it is displaced outward in the vehicle width direction. Accordingly, the wheel support 8 is displaced as indicated by the phantom line in FIG. 6B, so that toe-out during braking of the front wheels 16 can be suppressed.

  Each of the straight portions 34a and 34b extends along the outer peripheral portion of the elastic bushing 24, and an intermediate portion in the longitudinal direction thereof is 25 to 35 degrees (an angle γ in the figure) from the vehicle body longitudinal axis C in a plan view. It is formed to come to a position. Further, the straight portions 34a and 34b are formed so that one end in the longitudinal direction thereof coincides with the vehicle body longitudinal axis C, that is, at a position of 0 to 5 degrees from the vehicle longitudinal axis C. With these configurations, toe-out during braking of the front wheels 16 is suppressed, the amount of deformation of the elastic bush 24 in the longitudinal direction of the vehicle body is made relatively large, and the ride comfort is ensured, and the amount of deformation in the vehicle width direction is excessive. Therefore, it is possible to ensure the operability without increasing the size. Further, since the longitudinal direction of the straight portions 34a and 34b is formed so as to extend in a direction substantially parallel to the direction in which the tie rod 18 extends, toe-out during braking of the front wheels 16 can be more effectively suppressed. . Note that the same effect can be obtained even if only one of the first straight part 34a and the second straight part 34b is formed in the straight part 34.

1 is a perspective view showing a front suspension device for an automobile according to an embodiment of the present invention. It is the top view which looked at the right front-wheel side of the front suspension apparatus of the motor vehicle by embodiment of this invention from the vehicle body upper direction. It is the front view which looked at the right front-wheel side of the front suspension apparatus of the motor vehicle by embodiment of this invention from the vehicle body front. It is a top view which shows the lower arm of the front suspension apparatus of the motor vehicle by embodiment of this invention. It is the conceptual diagram which looked at the suspension apparatus for demonstrating the anti-dive geometry of a front suspension, and explaining the displacement of a lower arm by the reaction force of a buffering device from the vehicle width direction side. The conceptual diagram (a) of the right front wheel side of the suspension device for explaining the toe-out displacement of the wheel support during braking as viewed from above the vehicle body, and the displacement during braking of the suspension arm, wheel support and tie rod according to the embodiment of the present invention. It is the conceptual diagram (b) which looked at the right front-wheel side of the suspension apparatus for demonstrating from the vehicle body upper direction. It is a top view which shows the lower arm of the front suspension apparatus by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front suspension apparatus 2 Suspension cross member 4 Upper arm 6 Lower arm 6a, 6b Front arm part, rear arm part 6c, 6d Inner end part in the vehicle width direction 6e Connection part to wheel support 8 6f Shock absorber connection part 8 Wheel support 10 Buffer Device 16 Front wheel 20 Connection portion of the upper arm to the vehicle body on the front side of the vehicle body 22 Connection portion of the upper arm on the vehicle body side of the vehicle rear side 24 Elastic bush 25 Elastic bush extending in the vertical direction 26 Connection of the lower arm to the vehicle body on the front side of the vehicle body (Connecting part of the front arm to the vehicle body)
28 Connecting part of the lower arm to the car body on the rear side of the car body (connecting part of the rear arm part to the car body)
34 Straight part A Axis connecting the connecting part to the vehicle body and the connecting part to the wheel support of the front arm part of the lower arm B Bending machine axis

Claims (5)

It is a front suspension device of a double wishbone type automobile,
An upper arm,
An A-type lower arm connected to the vehicle body at two locations, including a front arm portion extending substantially in the vehicle width direction from the vehicle body front side connection portion with the vehicle body and a vehicle body rear side connection portion with the vehicle body. An A-type lower arm having a rear arm portion extending obliquely forward in the direction outward;
An elastic bush provided so that a central axis extends in a vertical direction of the vehicle body at a connecting portion on the vehicle body rear side of the lower arm;
A wheel support connected to the upper arm and the lower arm to rotatably support a wheel;
A shock absorber having an upper end connected to the vehicle body and a lower end connected to the lower arm;
A front suspension device for an automobile, wherein a rear arm portion of the lower arm is configured to be displaced upward of a vehicle body by a reaction force of the shock absorber during braking.   The axial line of the said shock absorber is comprised so that it may extend toward the vehicle body front side of the axis line which connects the connection part of the vehicle body front side of the said lower arm, and the connection part of the said wheel support toward upper part from the downward direction. Front suspension device for automobiles.   The lower end portion of the shock absorber is attached to the lower arm on the vehicle body front side of the axis connecting the connecting portion of the lower arm on the vehicle body front side and the connecting portion of the wheel support. Automobile front suspension device.   The lower end of the shock absorber is attached to the lower arm on the vehicle body upper side of the axis connecting the front arm connecting portion of the lower arm and the wheel support, and the axis of the shock absorber extends downward from above. 4. The device according to claim 1, wherein the lower arm is disposed so as to extend obliquely forward with respect to an axis connecting the connecting portion of the lower arm on the vehicle body front side and the connecting portion of the wheel support. The vehicle front suspension apparatus described. Further, a steering gear unit fixed at a position in front of the vehicle body from the upper arm and the lower arm of the vehicle body, and extending obliquely forward from the steering gear unit outward in the vehicle width direction, the vehicle body front of the steering gear unit and the wheel support. A tie rod that connects the ends,
The elastic bush has two straight portions that extend along the outer peripheral portion thereof and face each other. These straight portions are, in plan view, a line connecting them is outside the vehicle width direction with respect to the vehicle longitudinal direction. It is arranged to extend obliquely backward toward
5. The front suspension device for an automobile according to claim 1, wherein the shock absorber is disposed so that its axis extends obliquely downward from the upper side to the lower side in the vehicle width direction.

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