JPH0211252Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a steering link mechanism, and more particularly, to a steering link mechanism suitable for use in an axle-type front suspension vehicle with a leading arm.

[Prior Art] Generally, in an axle-type suspension vehicle using a leading arm, the axle tube is supported by a pair of leading arms, a spring, and a lateral control rod. The tube is installed in the horizontal plane of the vehicle by connecting the vicinity of one frame to the other frame, and maintains its position in the left-right direction of the vehicle. Here, the connection point between the lateral control rod and the frame is designated as a, and the connection point between the lateral control rod and the axle tube is designated as b.

Further, the pitman arm is connected to a side arm via a relay rod disposed substantially within the horizontal plane of the vehicle, and transmits rotation of the pitman arm to a steering knuckle connected to the side arm. Here, the connection point between the relay rod and the pitman arm is c, and the connection point between the relay rod and the side arm is d.

These connection points are connection point a and connection point c,
Further, the connection point b and the connection point d are arranged to coincide with each other when viewed from the horizontal direction of the vehicle. Therefore, during rolling that occurs when the vehicle turns, the locus in which the connecting point a rotates around the connecting point b coincides with the trajectory in which the connecting point c rotates around the connecting point d. Therefore, even during rolling, the relationship between the tire turning angle and the meandering angle, ie, the rotation angle of the pitman arm, matches, and there is no possibility that the steering wheel will be returned to its original position.

[Problem that the invention attempts to solve]

However, when the vehicle turns, the vehicle body rolls,
Axle steer occurs because the leading arm on the inside of the turn rotates upward, and the turning characteristics tend to oversteer. Therefore, the turning characteristics cannot be made to have the tendency of understeer required for general vehicles.

This invention was devised in view of the above-mentioned conventional problems, and an object thereof is to provide a steering link mechanism that can make the turning characteristics of the vehicle understeer when turning.

[Means for solving problems]

In order to achieve the above object, the steering link mechanism according to this invention supports an axle tube so as to be able to swing relative to the vehicle body and approximately horizontally by a pair of leading arms that are rotatably connected to the vehicle body. A lateral control rod and a relay rod are respectively disposed substantially parallel to the axle tube, both ends of the lateral rod are rotatably connected to the axle tube and the vehicle body, and one end of the relay rod is connected to the axle tube. One end of the lateral rod of the axle tube is rotatably connected to a side arm of a steering knuckle provided at one end of the connected side, and the other end of the relay rod is rotatably connected to a pitman arm. In the steering link mechanism, the position of the connection point d between the relay rod and the side arm is determined relative to the plane that includes the two connection points α and β between the leading arm and the vehicle body, and the connection point b between the lateral rod and the axle tube. They are characterized in that they are arranged at a fixed distance γ in the upward direction.

[Effect]

With this configuration, by separating the distance γ, the connection point c between the pitman arm and the relay rod is reduced when the vehicle is rolling.
A difference is created between the locus of rotation of the connecting point d around the connecting point d and the locus of the rotating of the connecting point c around the connecting point b, and this difference causes the tire turning angle to be reduced or decreased through the relay rod. In other words, the turning characteristics tend to be understeer.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a plan view showing the unsprung part of an axle-type front suspension vehicle with a leading arm to which the steering link mechanism according to this invention is applied, Figure 2 is a front view of the unsprung part, and Figure 3 is a rod FIG. 3 is a model diagram showing the positional relationship between the connecting point of the leading arm and the connecting point of the leading arm.

Below a frame 1 constituting a vehicle body, unsprung parts such as a leading arm 3, an axle tube 5, and a steering link mechanism are arranged.

That is, one end of each of the pair of leading arms 3 is rotatably supported by the frame 1, and the other end supports the axle tube 5 to maintain the position of the sprung portion including the frame 1 in the longitudinal direction of the vehicle. ing. Here, connection points between the leading arm 3 and the frame 1 are assumed to be α and β. A lateral control rod 7 is arranged substantially parallel to the axial direction of the axle tube 5. One end of the lateral control rod 7 is rotatably supported by one frame 1, and the other end is rotatably supported by the outer periphery of an axle tube 5 located near the other frame 1. Thereby, the position of the sprung portion of the axle tube 5 in the left-right direction of the vehicle is maintained. Here, the connection point of the lateral control rod 7 with the frame 1 and the connection point with the axle tube 5 are designated as a and b, respectively.

Furthermore, steering knuckles 9 and 10 are pivotally supported at both ends of the axle tube 5, respectively.
The steering knuckles 9 and 10 are connected by a tie rod 13 via a knuckle arm 11, so that an operating force acting on the steering knuckle 9 from a pitman arm 19 (described later) can be transmitted to the steering knuckle 10.

A side arm 15 is fixed to the steering knuckle 9 so as to extend toward the front of the vehicle, and the tip of the side arm 15 is rotatably connected to one end of a relay rod 17, and is attached to the frame 1 via the relay rod 17. It is connected to the pitman arm 19 of the steering gear section. This relay rod 17 is arranged parallel to the lateral control rod 7, that is, approximately in the horizontal direction of the vehicle, and has approximately the same length as the lateral control rod 7. In addition, the connection point of the relay rod 17 with the Pitman arm 19 and the side arm 1
Let the connection points with 5 be c and d, respectively.

Here, as shown in FIG. 3, the connection point d is set at a distance γ above the plane A including the connection points α, β, and b, and this distance γ makes the turning characteristics understeer and prevents the turning characteristics from kickback. The value shall be kept within the permissible limit.

That is, as shown in FIG. 2, when the vehicle is rolling, the locus of the connecting point c becomes a circular arc with the connecting point d as the center and the relay rod 17 as the radius due to the existence of the distance γ when the tire turning angle is fixed. R ₁
becomes. Furthermore, in the same case, the trajectory of the connection point c when the relay rod 17 is not restrained is as follows, since the frame 1 to which the pitman arm 19 is attached rotates while being restrained by the lateral control rod 7 when the vehicle is rolling. An arc whose center is support point b and whose radius is the distance in the same figure.
It becomes R ₂ . As a result, a difference δ occurs between both trajectories R ₁ and R ₂ ,
This difference δ causes the phenomenon described below.

When the steering angle is fixed, that is, when the pitman arm 19 is fixed, when the vehicle rolls, the connection point c
rotates along the locus _R2 , so as the connecting point c rotates, the relay rod 17 moves along the connecting point d by a difference δ.
, the tire turning angle is made small, and the turning characteristics tend to understeer. Furthermore, when the tire turning angle is fixed, the frame 1 rotates around the connecting point b when the vehicle rolls, but since the connecting point c is restrained by the relay rod 17, it rotates along the trajectory _R1. . Therefore, as the connecting point c rotates, the Pitman arm 19 changes due to the difference δ.
It rotates in the direction of the connection point c and causes a backlash of returning the handle.

Therefore, in consideration of the above phenomenon, the value of γ is set to an appropriate value such that the difference δ tends to cause the steering characteristics to understeer and to suppress the kickback within the allowable limit. Incidentally, since the difference δ is also affected by the relative length between the lateral control rod 7 and the relay rod 17, the difference δ is actually set to an optimal value by adjusting the distance γ and the relative length. .

Next, the action will be explained.

In Figure 2, the right tire side is the inside of the turn. Rolling occurs when the vehicle turns, but in this case the right side of the frame 1 rotates upward with the pitman arm 19 fixed because the occupant holds the steering wheel fixed. Therefore, as described above, the relay rod 17 moves in the direction of the connection point d, and the steering knuckle 9 rotates in a direction that reduces the tire turning angle. Therefore, the steering characteristics tend to understeer. This effect becomes larger as the rolling becomes more significant, that is, as the difference δ becomes larger.

According to the above embodiment, since the connection point d is set above the distance γ with respect to the plane A including the connection points α, β, and b, when the vehicle is rolling, the connection centering on the connection point d A difference δ occurs between the rotation locus of point c and the rotation locus of the same connection point c centered on connection point b. This difference δ can make the turning characteristics more prone to understeer, thereby improving the directional stability of the vehicle.

Also, since the lengths of the lateral control rod 7 and the relay rod 17 are almost the same,
The difference δ is symmetrical with respect to the relay rod 17, so that the tendency of understeer that occurs when rolling to the same extent on the left and right sides is made almost the same, and the left and right steering balance can be maintained.

[Effect of idea]

As described above, according to the steering link mechanism according to the present invention, the turning characteristics when the vehicle turns are made understeer, and the directional stability of the vehicle can be improved.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the unsprung part of an axle-type front suspension vehicle with a leading arm to which the steering link mechanism according to this invention is applied, Figure 2 is a front view of the unsprung part, and Figure 3 is a rod FIG. 3 is a model diagram showing the positional relationship between the connecting point of the leading arm and the connecting point of the leading arm. 1...Frame, 3...Leading arm, 5
... Axle tube, 7 ... Lateral control rod, 9, 10 ... Steering knuckle, 15 ... Side arm, 17 ... Relay rod, 19 ... Pitman arm, α, β ... Connection between leading arm and frame Point, b...The connection point between the axle tube and the lateral control rod, d...The connection point between the side arm and the relay rod, A...The plane, γ...The distance between the plane A and the connection point d.

Claims (1)

[Scope of utility model registration request] An axle tube is supported swingably and substantially horizontally relative to the vehicle body by a pair of leading arms rotatably connected to the vehicle body, and a lateral control rod and a relay rod are mounted substantially parallel to the axle tube. and both ends of the lateral rods are rotatably connected to the axle tube and the vehicle body, respectively, and one end of the relay rod is provided at one end of the axle tube on the side to which the one end of the lateral rod is connected. In a steering link mechanism, the relay rod is rotatably connected to a side arm of a steering nut, and the other end of the relay rod is rotatably connected to a pitman arm of a steering gear attached to the vehicle body. The connecting point with the arm is arranged at a certain distance upward with respect to a plane including two connecting points between the leading arm and the vehicle body and a connecting point between the lateral rod and the axle tube. steering link mechanism.