JPS63265712A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To improve an anti-dive effect, by supporting a front side car body supporting part of an upper arm to an outer cylinder of a damper mounted interposing in the vertical direction between a lower arm and a car body, in the case of a double-wishbone type vehicle suspension device. CONSTITUTION:If a nose dive is generated, a device, turning an upper arm 2 and a lower arm 3 to the upper with their respective car body side swivel axis S1, S2 serving as the center, moves a damper 11 to be contracted. Accordingly, the device, in which an outer cylinder 11a is displaced to the upper, displaces a front end car body side supporting part 2a of the upper arm 2 to the upper. Consequently, the car body side swivel axis S1 of the upper arm 2 tilts in a direction of large increasing a rear downward tilt angle. In this way, a large anti-dive effect is attained by increasing ratio of the crossing point of the swivel axis S1 with the swivel axis S2 of the lower arm 3, that is, the road surface height of a wheel in its momentary rotary center to the distance in the longitudinal direction from a grounded point.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an eggplant neck attachment for a vehicle, and particularly to an improvement in improving the anti-dive effect in a double wishbone type neck attachment.

(Prior Art) Conventionally, as a double wishbone type suspension device for a vehicle, as disclosed in Japanese Patent Application Laid-Open No. 60-135314, a wheel support member that rotatably supports a wheel, and a wheel support member for rotatably supporting the wheel, and a wheel support member for rotatably supporting the wheel, and An upper arm and an O arm that connect the upper and lower parts of the support member to the vehicle body so as to be vertically swingable, and a damper that is vertically interposed between the lower arm and the vehicle body and damps the vertical vibration of the wheel. is known. Incidentally, the upper arm and the lower arm are normally swingably supported by a strength member (frame, etc.) of the vehicle body at two front and rear support portions on the inner end side. It is disclosed that the inner end of the upper arm is supported by the outer cylinder of the damper instead of the vehicle body due to the arrangement of members and the like.

In such suspension devices, especially front suspension devices for front wheels, in order to suppress nose dive, which causes the vehicle body to drop due to inertial force when the vehicle is braked, it is usually fixed to the sides of the vehicle body as shown in Figure 2. Viewed from , the vehicle body side rocking axis S1 of the upper arm a is tilted rearward and downward, and the vehicle body side rocking axis S2 of the lower arm b is tilted rearward and upward, respectively, and these rocking axes St and '82 are tilted toward the wheels (
Front wheels) C are set so that they intersect at the rear, and when a rearward power F acts on the grounding point P+ of wheel C during braking, the wheel C momentarily rotates around the intersection P2 of the above-mentioned swing axes S+ and 82. The center of the wheel rotates in the rebound direction (that is, the direction that suppresses the bumping behavior of the wheels due to inertial force) relative to the vehicle body.

(Problem to be solved by the invention) By the way, as mentioned above, the effect of suppressing nose dive during braking, that is, the anti-dice effect, depends on the road surface height of the instantaneous rotation center of the wheel (the intersection of the swing axes S+ and 82) P2. The ratio of H to the length L in the longitudinal direction from the rear wheel contact point P1) is determined by -1/L, and the larger H/L is, the greater the anti-dive effect can be obtained. However, when H/L is increased, the front-back impact acting on the wheels due to irregularities in the road surface generates a large vertical component force, resulting in a problem of poor riding comfort. For this reason, H/L cannot be set too large, and a sufficient anti-dive effect cannot be achieved with YJ.
The current situation is that this is not the case.

The present invention has been made in view of the above points, and its purpose is to make the above F1/C value increase only during braking, with a simple configuration, without impairing riding comfort. This is to ensure a sufficient anti-dice effect.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a solution for a vehicle suspension system in which a wheel support member for supporting wheels is vertically swingably connected to the vehicle body by an upper arm and a lower arm. In the pension device, the support part on the ■■ side of the two front and rear vehicle body side support parts of the upper arm is supported by the outer cylinder of a damper vertically interposed between the lower arm and the vehicle body. be.

(Function) With the above configuration, in the present invention, when the vehicle nose dives due to inertia during braking (the wheels are in a bump state), the lower arm rotates upward, and there is a gap between the lower arm and the vehicle body. Since the vertically interposed damper contracts and its outer cylinder displaces upward, the vehicle body side support portion on the front side of the upper arm supported by the damper outer cylinder also displaces upward.

Therefore, the swing axis that connects the two front and rear support parts of the upper arm on the vehicle body side is inclined in the direction that increases the backward downward inclination angle, and the instantaneous rotation center of the wheel is the intersection of this swing wheel and the swing axis of the lower arm. Since the ratio H/L between the height 1'' and the length in the longitudinal direction from the wheel grounding point increases, a large anti-dive effect will be achieved.

On the other hand, during driving other than when braking, the above-mentioned 1-1/L is not set to a particularly large value, so that the riding comfort can be improved.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a double wishbone front suspension device for a vehicle according to an embodiment of the present invention, in which 1 is a wheel support member that supports a front wheel (front wheel) via a drive shaft (not shown), 2 and Reference numeral 3 denotes an upper arm and a lower arm extending in the vehicle width direction that connect the wheel support member 1 to the vehicle body vertically +ffi vJ, and the outer end of the upper arm 2 is connected to the upper end of the wheel support member 1, and The ends are each connected to the lower end of the wheel support member 1 via ball joints 4.5.

- The bifurcated inner end of the lower arm 3 has two front and rear vehicle body side support portions 3a and 3b each having an elastic bushing 6.6 at the end of each branch. Part 3a
, 3b are each swingably supported by a strength member (such as a frame) of the vehicle body via a bracket 7. on the other hand,
Like the lower arm 3, the upper arm 2 has a forked inner end with a front 1! ! Two vehicle body side support parts 3a
, 3b, and the rear vehicle body side support part 3b is provided with an elastic bush 8 at the end of the branch part and is swingably supported by a strength member of the vehicle body via a bracket 9. The vehicle body side support portion 3a has a bifurcated portion that further branches into two forks.
Each of the double branched ends is provided with an elastic bushing 10°10. And this front side vehicle body side support part 3a
is located between the outer cylinder 11a of the damper 11, which is vertically interposed between the lower arm 3 and the vehicle body, from both sides of the rear of IyI with a double branched end or an elastic bushing 10°10, and the support shaft 12 are connected and supported so as to be able to swing through them.

In this case, the vehicle body side swing axis S+ of the upper arm 2 is between the longitudinal center point (located approximately on the central axis of the damper 11) between both elastic bushings 10°10 of the front vehicle body side support portion 3a and the rear vehicle body side swing axis S+. This is a straight line that passes through the center point of the elastic bush 8 of the side support portion 3b.

The damper 11 acts as a shock absorber to attenuate the vertical vibration of the wheel. Although its structure is not shown in detail in the figure, as is conventionally known, the damper 11 includes a cylinder filled with an incompressible fluid such as oil. The piston has an A refit and is connected to a piston rod, into which the piston is slidably inserted. This damper 11 is arranged in the vertical direction with the piston rod that extends and contracts with respect to the cylinder and the outer f111a side that covers the piston rod facing downward, and the lower end is pivoted on the lower arm 3, and the upper end (
The cylinder side) is attached to the vehicle body.

Note that 13 is a coil spring disposed on the upper outer periphery of the damper 11. In addition, the vehicle body side swing axes of the upper arm 2 and lower arm 3 (in the case of the lower arm 3, a straight line passing through the center point of both elastic bushings 6 and 6 of the vehicle body side support parts 3a and 3b) Sl, 82 are shown in FIG. As in the conventional case shown in FIG. 1, the swing axis S1 of the upper arm 2 is tilted rearward downward, and the swing axis S2 of the lower arm 3 is tilted rearward upward, respectively, and are set so as to intersect behind the wheels C. The ratio of the road surface height T1 of this intersection point (instantaneous rotation center of the wheel during braking) P2 and the longitudinal length from the wheel grounding point P1 H/L
is set relatively small.

Next, to explain the operation and effect of the above embodiment, the upper arm 2 and the lower arm 3 each have a swing axis S+ on the vehicle body side. , S2, and vertically interposed between the lower arm 3 and the vehicle body, the lower piston rod contracts with respect to the upper cylinder, causing the piston rod to move upwardly. Since the covering outer cylinder 11a is displaced upward, this damper 1
The front vehicle body side support portion 3a of the upper arm 2 supported by the outer cylinder 11a of the upper arm 2 is also displaced upward. Therefore, the vehicle body side swing axis S1 of the upper arm 2 is inclined in the direction in which the backward downward inclination angle increases, and the instantaneous rotation of the wheel as the intersection of this swing axis S+ and the vehicle body side swing axis S2 of the lower arm 3 As shown in FIG. 2, the center P2 is closer to the wheel C side than the position in the set state, and the ratio of the road surface height H of the instantaneous rotation center P2 to the length L in the longitudinal direction - from the wheel grounding point P1 is H/L. Since this increases, the anti-dive effect that suppresses nose dive due to inertial force is greatly exerted, and running stability during braking can be improved.

On the other hand, when driving other than when braking, the above H/L remains set to a relatively small value and is not increased, so the longitudinal impact acting on the wheels due to irregularities in the road surface is Almost no directional force is generated, and a good riding comfort can be maintained.

Moreover, the structure of the suspension device is simply changed from the conventional one to a structure in which the front vehicle body side support portion 2a of the upper arm 2 is supported by the outer cylinder 11a of the damper 11, and new members etc. This method is extremely advantageous in terms of implementation since it does not require any of the above.

In the above embodiment, in the setting state, the vehicle body side swing axis S1 of the upper arm 2 is tilted rearward and downward, and the vehicle body side rocking axis S2 of the lower arm 3 is tilted rearward and upward, as in the conventional case. Front vehicle body side support part 2a
Depending on the relationship with the value that can increase the inclination angle of the swing axis S1 of the upper arm 2 during braking by supporting the outer cylinder 11a of the damper 11, it is possible to It may be in a zero state, that is, in a state in which it extends horizontally in the front-rear direction.

(Effects of the Invention) As described above, according to the vehicle pension device of the present invention, the front side support portion of the upper arm is connected to the outer cylinder of the damper vertically interposed between the lower arm and the vehicle body. With a simple structure that just supports it, the 7-arm swing axis on the vehicle body side tilts during braking! Since the ratio 1/L of the road surface height H at the instantaneous rotation center of the retainer ring to the length 1- in the longitudinal direction from the wheel grounding point increases, the anti-dive effect can be sufficiently achieved while maintaining good riding comfort. It has excellent practical effects.

[Brief explanation of drawings]

FIG. 1 is an rI view showing an embodiment of the present invention, and FIG. 2 is a schematic diagram for explaining the anti-dive effect. 1...Wheel support member, 2...Upper arm, 2a. 2b...Vehicle side support part, 3...Lower arm, 11.
...Da Figure 2 Figure 1

Claims (1)

[Claims] (1) In a suspension system for a vehicle in which a wheel support member supporting a wheel is vertically swingably connected to the vehicle body by an upper arm and a lower arm, the front support portion of the two vehicle body side support portions on the front and rear of the upper arm is A suspension device for a vehicle, characterized in that the suspension device is supported by an outer cylinder of a damper vertically interposed between the lower arm and the vehicle body.