JP2823854B2 - Steering wheel suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is steered through a knuckle arm and a tie rod, and extends laterally between a vertical position of a hub carrier and a vehicle body. The present invention relates to a steering wheel suspension device connected by an upper link arm and a lower link arm. <Conventional technology> As a steering wheel suspension device capable of minimizing the moving space of the wheel at the time of turning while satisfying the maneuverability and running stability, for example, Japanese Patent Publication No. 52-9889 A structure has been proposed in which the upper and lower positions of a hub carrier that supports wheels are connected to a vehicle body via a pair of lateral link arms, respectively, as disclosed in Japanese Patent Application Laid-Open Publication No. H11-163,036. The wheel steered by the link mechanism having such a structure turns around the instantaneous rotation center given by the intersection of the straight lines connecting the pivot points of the vehicle body and the hub carrier of the lateral link arms arranged side by side. . On the other hand, the steered wheels are steered by connecting a tie rod extending in the vehicle width direction to a knuckle arm protruding from the hub carrier along the longitudinal direction of the vehicle and applying a lateral displacement to the tie rod. Is common. Looking at the relationship between the knuckle arm protruding toward the rear of the vehicle and the tie rod connected to it when turning,
The extension of the straight line connecting the pivot points of the tie rods and the instantaneous center of rotation of the virtual kingpin axis at this time have a close relationship on the inner ring side, that is, the knuckle arm and the tie rod on the inner ring side in this case are It is known that it has a tendency to form toggles. <Problems to be Solved by the Invention> In order to prevent the steering linkage from forming a toggle, it is usual that the displacement amount of the tie rod is specified by a stopper or the like, but the toggle margin of the steering linkage with respect to the steering angle is Preferably, it is as large as possible. Based on such a viewpoint, a main object of the present invention is to provide a steering wheel suspension device capable of increasing a toggle margin between a knuckle arm and a tie rod during steering as much as possible. . <Means for Solving the Problems> According to the present invention, a knuckle arm projecting rearward from a lower portion of a hub carrier that rotatably supports wheels, and a knuckle arm The vehicle is steered via a tie rod which is connected and extends in the vehicle width direction, and is connected between the upper and lower positions of the hub carrier and the vehicle body by an upper link arm and a lower link arm which respectively extend in the lateral direction. A steering wheel suspension device comprising: a pair of lower link arms which are arranged side by side in front and rear; and a dimension between connection points of the pair of lower link arms with a vehicle body and a hub carrier is smaller than that of a rear side. When the front link arm of the pair of lower link arms is placed in a horizontal state, the rear link arm is inclined downward with respect to the pivot point with the vehicle body. The instantaneous center of rotation of the virtual kingpin shaft at this time is separated from an extension of a straight line connecting both ends of the tie rod, thereby providing a steering wheel suspension device. <Operation> In this way, the apparent length of the rear lower link arm (the length projected on a horizontal plane, the same applies hereinafter) and the length of the suspension are shortened on the rebound side where the suspension extends. As a result, the instantaneous rotation center on the inner ring side, which tends to rebound when turning, can be pushed back.
Therefore, the lateral displacement amount of the tie rod at the same turning angle can be further reduced, and the toggle margin of the steering linkage can be increased. Embodiments Hereinafter, the present invention will be described in detail with reference to the accompanying drawings with reference to specific embodiments. 1 and 2 show a steering wheel suspension according to the invention. The wheel 1 is rotatably supported by a bearing 3 which is integrally and laterally protruded from a hub carrier 2. From the lower part of the hub carrier 2, the knuckle arm 4
Are integrally extended rearward, and a tie rod 5 for transmitting a steering force is pivotally attached to a free end thereof. One end 6a, 7a of the upper link arm 6, 7 is pivotally connected via a ball joint to the front and rear position of the upper portion of the hub carrier 2, and the other end 6b, 7b of the upper link arm 6, 7 Each is connected to a vehicle body (not shown) via a ball joint. Further, one end 8a, 9a of a lower link arm 8, 9 is pivotally connected via a similar ball joint to the front / rear position below the hub carrier 2, and the other end 8b, 9b of the lower link arm 8, 9 is provided.
Has a front end 8b through a damper and a rear end 9b
Are connected to the vehicle body via bushes. The other ends 8b and 9b can be connected to the vehicle body via ball joints as in the case of the one ends 8a and 9a, but since the lower left and right angular displacements of the lower link arms 8 and 9 with respect to the vehicle body are relatively small, The angular displacement of the lower link arms 8 and 9 accompanying the steering can be sufficiently tolerated even by bending of the rubber bush or the like. The rear lower link arm 9 of these lower link arms 8 and 9 extends substantially linearly along the vehicle width direction,
The front lower link arm 8 extends obliquely forward of the vehicle body so as to also act as a radius rod.
A lower end of a shock absorber 10 composed of a compression coil spring and an oil damper is connected to an intermediate portion of the rear lower link arm 9, and a stabilizer 11 is provided near the shock absorber connection portion of the rear lower link arm 9. Are connected. The upper end of the shock absorber 10 is connected to a vehicle body (not shown), but the upper link arms 6 and 7 are respectively inclined in the front-rear direction with respect to the vehicle width direction so as not to interfere with the shock absorber 10. Extending. In this embodiment, the drive wheels of a front-wheel drive vehicle are shown, and a part of the drive shaft indicated by reference numeral D in FIG. In this way, the wheel 1 is supported so as to be able to move up and down,
Moreover, the change of the camber angle, the toe angle, and the like can be freely set by appropriately selecting the length of the link, the position of the pivot point, and the like. The steering force is transmitted to the hub carrier 2 by applying a traction force to the tie rod 5 in the left-right direction. In this case, the wheels 1 are steered about a virtual kingpin axis described below. Focusing on the upper link arms 6 and 7, as shown in FIG.
Is given as a locus 13 drawn by the intersection of the extension lines connecting the pivot points at both ends of both upper link arms 6 and 7. Focusing on the lower link arms 8.9, as shown in FIG. 4, the instantaneous center of rotation 14 at the lower end portion of the hub carrier 2 is also an extension line connecting the pivot points at both ends of both lower link arms 8.9. Given as a locus 15 of the intersection of Therefore, the rotation center axis of the hub carrier 2, that is, the virtual kingpin axis is
It is given by a line connecting these instantaneous rotation centers 12 and 14. By the way, as shown in FIG. 5, paying attention to the turning inner wheel side of the suspension device in which the tie rod is provided behind the axle, both ends 5a and 5b of the tie rod 5, that is, the connection end to the knuckle arm and the connection end to the rack shaft The center of the virtual kingpin axis at this time on the extension of the straight line L connecting
It can be seen that 14 'is in the approaching direction. This means
This means that the tie rod 5 and the knuckle arm 4 tend to form a toggle. In order to increase the toggle margin as much as possible, it is conceivable to increase the dimensions of the knuckle arm and the tie rod or to reduce the amount of forward movement of the center of the kingpin axis. Increasing the size is not preferable in terms of layout. Therefore, in the present invention, attention is paid to the fact that the displacement of the inner ring at the time of turning is a rebound tendency, and the apparent size of the rear lower link arm 9 at the time of rebound is changed to the front lower link arm 8.
It is configured so as to be shorter in comparison with. As shown in FIG. 6, a straight line 11 connecting both ends 8a and 8b of the front lower link arm 8 in a natural state extends substantially in the horizontal direction, whereas both ends 9a of the rear lower link arm 9 extend in the horizontal direction.・ The straight line l2 connecting 9b has a dihedral angle. As a result, the rate of decrease of the length of the lower link arms 8 and 9 projected on the horizontal plane when rebounding from the horizontal state,
As shown by δ1 and δ2 in FIG. 6, the rear lower link arm 9 is larger than the front lower link arm 8, and the apparent dimension of the rear lower link arm 9 during rebound is The effect is shorter than that of the lower link arm 8. On the other hand, one ends 8a, 9a of both lower link arms 8, 9 are connected to the hub carrier 2, which is a rigid body, and the longitudinal distance between them is mechanically determined. Therefore, the locus of the lower end of the hub carrier 2 given at the intersection of the two lower link arms 8 and 9 is pulled by the rear lower link arm 9,
Rather, it will move backward on the rebound side. Thereby, the knuckle arm 4 and the tie rod 5 are also relatively displaced in the return direction, and the toggle margin at the time of rebound increases. At the same time, by increasing the dimension of the front lower link arm 8, the radius of curvature of the front lower link arm 8 is further increased, thereby reducing the rate of change of the apparent dimension of the front lower link arm 8. Can be. By setting the relationship between the two lower link arms 8 and 9 to the above-described configuration, the rear lower link arm 9 can be viewed from the front lower link arm 8 on the bump side where the suspension contracts. The hanging dimension is longer. This means that the instantaneous rotation center 14 at the lower end portion of the hub carrier 2 is displaced forward as the bump bumps, that is, the caster angle is increased, whereby the anti-dumb effect can be obtained. <Effects of the Invention> As described above, according to the present invention, the toggle margin of the steering linkage on the turning inner wheel side can be further increased, and the degree of design freedom in improving the maneuverability of the vehicle can be increased. This makes it possible to improve the characteristics of the steering wheel suspension device, which has a great effect. Further, as described above, since the caster angle at the time of bump can be increased, there is also an effect that anti-dive properties can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a steering wheel to which a suspension device according to the present invention is applied. FIG. 2 is a plan view of the suspension device of FIG. FIG. 3 is a skeleton diagram showing the geometric relationship of the upper link. FIG. 4 is a skeleton diagram showing the geometric relationship of the lower link. FIG. 5 is a plan view of the inner wheel side during turning. FIG. 6 is an elevational view showing a change in apparent length accompanying rotation of the front and rear lower link arms. 1 ... wheels 2 ... hub carrier 3 ... bearings 4 ... knuckle arms 5 ... tie rods, 6-9 ... link arms 6a-9a ... one end, 6b-9b ... other end 10 ... buffer Device, 11… Stabilizers 13, 15… Locus, 12, 14… Instantaneous center of rotation

Claims (1)

(57) [Claims] The hub is steered via a knuckle arm protruding rearward below a lower portion of a hub carrier that rotatably supports wheels, and a tie rod connected to the knuckle arm and extending in the vehicle width direction. A steering wheel suspension device comprising an upper link arm and a lower link arm extending in a lateral direction between a vertical position of a carrier and a vehicle body, wherein the lower link arms are arranged in front and rear. The pair of lower link arms has a larger dimension between the connection points of the lower link arm with the vehicle body and the hub carrier, the front side being larger than the rear side, and the front link arm of the pair of lower link arms is When placed in a horizontal state, the rear link arm is inclined downward with respect to the pivot point with the vehicle body, and the virtual key at this time is viewed from an extension of a straight line connecting both ends of the tie rod. A steering wheel suspension device wherein the instantaneous rotation centers of the wingpin shafts are separated from each other.