JPS6248601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a front suspension of an automobile. In particular, the invention relates to a combination of front suspension and steering device of a motor vehicle.

(Prior art) For example, in a front-engine, front-drive vehicle, if the engine is installed horizontally, the center of gravity of the power unit, including the transmission mechanism, will be displaced laterally from the center line in the longitudinal direction of the vehicle. The load on a certain front wheel becomes different between the left and right wheels. Furthermore, in rear-drive automobiles that are often used by one person, the front wheel loads generally differ between the left and right wheels. If there is a difference in the left and right front wheel loads in this way, the sum of the cornering forces acting on the left and right wheels when turning will be different when turning to the right and when turning to the left, resulting in a difference in the left and right steering. Differences occur in characteristics. In order to solve this problem, in Utility Model Application No. 56-141805, the elasticity of the rubber bushings used to attach the suspension arm of the front wheel to the vehicle body was made different between the left and right sides to offset the difference in steering characteristics between the left and right sides. A new structure has been proposed. However, with this structure, when the elasticity of the rubber constituting the rubber bushing changes due to aging, etc., the desired effect cannot be achieved.

(Object of the Invention) In view of the above points, an object of the present invention is to provide a highly reliable mechanism that can cancel out the difference in left and right steering characteristics.

(Structure of the Invention) In order to achieve the above object, the present invention has the following structure. That is, the front suspension of an automobile according to the present invention includes a suspension arm on each side of the vehicle body that extends in the lateral direction of the vehicle body and has one end attached to the vehicle body so as to be swingable in the vertical direction, and a suspension arm that is rotatably attached to the other end of the suspension arm. It consists of a wheel support member that is attached to the wheel support member and rotatably supports the front wheels of the car, and a tie rod that connects the knuckle arm provided on the wheel support member to the car steering mechanism, and the left and right steering characteristics are different. , is characterized in that the installation inclination angle of the suspension arm is different between the left and right sides when viewed from the front of the vehicle so that the difference in steering characteristics between the left and right sides is canceled out. The principle of the present invention will be explained with reference to the drawings. In FIG. 1, a right front wheel 1a and a left front wheel 1b are rotatably supported by wheel support members 2a and 2b, respectively. Wheel support members 2a, 2b
is the suspension arm 3 that extends in the lateral direction of the vehicle body.
The suspension arms 3a and 3b are rotatably attached to the outer ends of the suspension arms 3a and 3b, and the inner ends of the suspension arms 3a and 3b are attached to the vehicle body 4 so as to be swingable in the vertical direction. Further, the lower ends of suspension struts 5a, 5b are fixed to the wheel support members 2a, 2b, and the upper ends of the suspension straps 5a, 5b are rotatably attached to the vehicle body 4. Moreover, the wheel support member 2a,
2b is provided with a knuckle arm, which is not shown in detail in FIG.
a and 7b are connected. This type of suspension is called a strut type, and steering interference occurs when the wheels bump or rebound. That is, referring to FIG. 2, when the wheel bumps and displaces upward from the position shown by the solid line, the suspension arm 3a swings upward around the attachment point to the vehicle body 4 to the position shown by the imaginary line. Accompanying this swinging, the suspension strut 5a also moves from the position shown by the solid line to the position shown by the imaginary line, and at the same time, the tie rod 7a also swings upward. At this time, if the steering angle of the wheel is maintained constant, the attachment point 8 of the tie rod 7a to the wheel support member will not move along the arc centered on the swing center 9, but will move to a point that deviates from the arc. It will reach 8A. However, since the tie rod 7a cannot be expanded or contracted, the above attachment point is actually the pivot center 9.
The wheel will move along an arc centered at and will reach point 8B, and the wheel will be rotated in the direction to increase or decrease the steering angle by an angle corresponding to the distance between points 8A and 8B. . That is, when a wheel bumps, the steering angle of the wheel is changed, which is what is called steering interference. This steering interference also occurs during rebound when the wheels are displaced downward, and the magnitude and direction of the steering interference vary depending on the mounting angle of the suspension arm when viewed from the front. Further, the knuckle arm is supported by a link mechanism consisting of suspension arms 3a, 3b and tie rods 7a, 7b. Therefore, the posture of the knuckle arm during bump rebound, that is, the wheels 1a and 1b
The toe change in suspension arms 3a, 3
b. Determined by the locus of movement of the connecting points of tie rods 7a and 7b with the knuckle arms. For this reason,
The magnitude of the toe change varies depending on the inclination angle of the suspension arms 3a, 3b with respect to the horizontal line viewed from the front of the vehicle body. The larger the inclination angle, the larger the amount of toe change. Focusing on this point, the present invention aims to cancel the difference in left and right steering characteristics inherent in an automobile by making the mounting inclination angles αa and αb of the suspension arms 3a and 3b different on the left and right sides. This is what I did.

(Effects of the Invention) In the present invention, as described above, the installation angle of inclination of the suspension arm when viewed from the front of the vehicle body is not the same on the left and right sides, and the difference in the angle of inclination is due to the left and right steering characteristics inherent in the automobile. Therefore, the difference in left and right steering characteristics can be comprehensively eliminated. Furthermore, since there is no need to rely on the elastic modulus of the rubber bushing to cancel out the difference in left and right steering characteristics, a highly reliable mechanism can be obtained. In addition, even if the tie rod and suspension arm are arranged differently in the front and rear direction,
Since the direction of steering interference is simply reversed, the difference in steering characteristics between left and right steering can be reduced by appropriately changing the installation angle of the suspension arm on the left and right sides in such types of automobiles as well. It can be resolved.

(Example) Referring to FIGS. 3 and 4, right front wheel 1
a is rotatably supported by a wheel support member 2a, and the left front wheel 1b is similarly supported by a wheel support member 2b.
is rotatably supported. Since the structures on the left and right sides are almost symmetrical, only the mechanism on the right side will be explained below, and corresponding parts of the mechanism on the left side will be shown with the same reference numerals as those on the right side, with a subscript b instead of the subscript a on the right side. omitted.

An arm 11a is formed on the wheel support member 2a, and the outer end of a suspension arm 3a is rotatably connected to the tip of the arm 11a via a ball joint 12a. The suspension arm 3a is an A-type arm that extends in the lateral direction of the vehicle body.
The inner end is connected to the vehicle body 4 at two points separated in the longitudinal direction of the vehicle body by rubber bushings 20a and 21a.

Referring to FIG. 3, an arm 21a extending obliquely upward is formed on the wheel support member 2a, and the lower end of a suspension strut 5a is fixed to the tip of this arm 21a. The upper end of the suspension strut 5a is rotatably attached to the vehicle body 4.

A knuckle arm 15a is provided on the wheel support member 2a so as to extend diagonally rearward, and the tip of this knuckle arm 15a is connected to the outer end of the tie rod 7a. The inner end of the tie rod 7a is connected to one end of the steering mechanism 6. In this example,
The steering mechanism 6 is of the rack and pinion type, and its steering shaft 20 is connected to a steering wheel (not shown) of the automobile.
As seen from the rear of the vehicle body as shown in Fig. 3, the arm center line La of the right suspension arm 3a is inclined outward and downward with respect to the horizontal line H, and the center line Lb of the left suspension arm 3b is arranged almost horizontally. ing. With this arrangement, when turning left, the right front wheel 1
The steering interference caused by the bump that occurs on wheel a tends to understeer, and similarly, the steering interference that occurs on the left front wheel 1b when turning to the right also tends to understeer, but the magnitude of that interference is different from that when turning to the left. becomes stronger. Therefore, if this mechanism is adopted for a car that shows a stronger understeer tendency when turning to the right than when turning to the left, or a car that shows a stronger tendency to oversteer when turning to the left than when turning to the right, The difference in steering characteristics can be offset.

FIG. 5 shows an example in which tie rods 7a and 7b are located in front of the front wheels 1a and 1b, unlike the previous example. In this example, steering interference appears in a tendency opposite to the previous example. That is, when the suspension arm is inclined outwardly and downwardly, steering interference appears as a tendency to oversteer, and this tendency becomes stronger on the side where the angle of inclination is large.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of a front suspension illustrating the principle of the present invention, FIG. 2 is a schematic diagram illustrating the principle of steering interference, and FIG. 3 is a rear view of the front suspension illustrating an embodiment of the present invention. FIG. 4 is a plan view thereof, and FIG. 5 is a schematic plan view showing another embodiment. 1a, 1b...Front wheel, 2a, 2b...Wheel support member, 3a, 3b...Suspension arm, 5a,
5b...Suspension strut, 6...Steering mechanism, 7a, 7b...Tie rod.

Claims (1)

[Claims] 1 Suspension arms on each side of the vehicle body that extend in the lateral direction of the vehicle body and have one end attached to the vehicle body so as to be swingable in the vertical direction, and a suspension arm that is rotatably attached to the other end of the suspension arm and allows the front wheels of the automobile to rotate freely. The suspension arm is composed of a supporting wheel support member and a tie rod that connects the knuckle arm provided on the wheel support member to the steering mechanism of the vehicle. A front suspension for an automobile is characterized in that the left and right sides have different inclination angles with respect to the horizontal line when viewed from the front of the vehicle so that differences in steering characteristics are canceled out.