JPH0447024Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a steering device, and more specifically, to a steering device in which the suspension geometry changes according to the steering angle.

(Prior art) Figure 8 shows the area around a general rack-and-pinion gearbox, where 2 indicates a rack bar;
4 is a tie rod, which are coaxially connected via a ball joint 12.

By the way, as is well known, the toe-in that changes as the suspension bounces and rebounds, and the difference in turning angle between the inner and outer wheels when the steering wheel is turned, both have a large effect on the maneuverability and stability of the vehicle. These are almost determined by the suspension type, link arrangement, space, etc. However, from the perspective of improving turning performance, depending on the size of the steering angle of the steering wheel,
It is desirable that these properties change. For example, when the steering angle is large, it is often better to have a tendency toward toe-in rather than toe-out, and it is often better to have a smaller difference in turning angle between the inner and outer wheels.

(Problem to be solved by the invention) However, in a conventional steering device in which a rack bar and a tie rod are coaxially connected, even if the steering angle changes, the relative position of the tie rod with respect to the vertical and longitudinal directions of the vehicle body remains unchanged. It does not change. Therefore, it is not possible to change the characteristics of changes in toe-in with respect to bounce and rebound of the suspension or the characteristics of changes in the steering angle difference between the inner and outer wheels depending on the magnitude of the steering angle.

Therefore, in this invention, in order to solve the above problems and further improve turning performance, we change the toe-in change characteristics and the change characteristics of the turning angle difference between the inner and outer wheels in response to changes in the steering angle of the steering wheel. The purpose of the present invention is to provide a steering device that enables the following.

(Means for Solving the Problems) Therefore, in the present invention, in order to achieve the above object, a rack bar is incorporated in the steering gear box so as to be relatively displaceable in the axial direction, and tie rods are attached to both ends of the rack bar. A steering device comprising a connecting joint portion, the rotating shaft being fixed to the joint portion and being attached to the connecting rack bar so that it cannot be displaced relative to the connecting rack bar in the axial direction and can rotate relative to the connecting rack bar;
A pin fixed to the rotating shaft, and a guide groove provided in the gear box with which the pin is engaged and guided, and the pin is engaged with and guided by a guide groove provided in the gear box, and the pin is engaged with the gear box and the gear box is guided. a guide groove having a shape that allows the rotary shaft to rotate relative to the gearbox according to relative displacement in the axial direction with respect to the gearbox; and a guide groove provided in the joint portion and arranged at an eccentric position with respect to the axis of the rotary shaft. We have created a steering device with a tie rod connection section.

(Function) According to the above structure, the tie rod connecting portion rotates around the axis of the rack bar in accordance with the steering angle of the steering wheel, and accordingly, the tie rod position also changes in the longitudinal direction and the vertical direction of the vehicle. Therefore, the magnitude of toe-in, the difference in turning angle between the inner and outer rings, and their change characteristics also change.

In this way, the toe-in change characteristics and the change characteristics of the steering angle difference between the inner and outer wheels can be changed in response to changes in the steering angle of the steering wheel.

(Example) Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings.

In the drawings, reference numeral 1 denotes a gearbox in a rack-and-pinion type steering device, in which a rack bar 2 that is displaced left and right in conjunction with steering wheel operation is housed via a rack bush 3. And, there are tie rods 4 on both the left and right ends.
A joint portion j is provided for each. The figure shows the left wheel side.

A shaft hole 5 is bored in the end face of the rack bar 2 to a predetermined depth along the axis, into which an insertion shaft 7 having a flange 6 formed at the center is inserted. A cap body 9 is loosely fitted to the insertion shaft 7 via a bearing 8, and the insertion shaft 7
is rotatably assembled by screwing this cap body 9 onto the rack bar 2. The outer end of the insertion shaft 7 is coaxially screwed into a joint base 11 via a bearing 10, and a ball joint 12 relative to the tie rod 4 is screwed into the joint base 11 at an eccentric position.

On the other hand, the rack bar 2 has a predetermined width at a position near the terminal end of the shaft hole 5, and extends approximately along the circumferential direction.
The relief groove 13 is cut out over a 180° range.
A pin 14 is screwed into the insertion shaft 7 through this escape groove 13. Further, a roller 15 is attached to the head of the pin 14, and is engaged with a predetermined guide groove 16 bulging out on the circumferential surface of the gearbox 1. However, this guide groove 16 is formed over a range corresponding to the relief groove 13, and as the rack bar 2 is displaced, the insertion shaft 7 is rotated to change the position (angular displacement) of the ball joint 12. In the neutral steering position, the ball joint 12 is in the imaginary position shown in FIGS. 4 and 5.

Therefore, the joint base 11 and the ball joint 12 constitute a joint part j provided at both ends of the rack bar 2 and connected to the tie rod 4.

Further, the insertion shaft 7 is fixed to the joint portion j, and functions as a rotating shaft that is attached to the rack bar 2 so that it cannot be displaced relative to the rack bar 2 in the axial direction and can rotate relative to the rack bar 2.

Further, the ball joint 12 is provided at the joint part j and constitutes a tie rod connection part arranged at an eccentric position with respect to the axis of the rotating shaft 7.

Subsequently, the functions and effects of this example formed as described above will be specifically explained.

When the handlebar is turned from a neutral state to the right, for example, and the rack bar 2 is displaced to the left in the figure, the roller 15 is displaced while being guided by the guide groove 16. This allows the insertion shaft 7 to
Since the ball joint 12 rotates clockwise as shown in the figure, it moves to the position shown by the solid line in FIG. In other words, it is displaced by b in the direction of vehicle travel, and displaced upward by a.

When the position of the ball joint 12 is deviated in this way, the following effects can be obtained.

Figure 6 is a bounce amount-toe-in characteristic diagram when the height of the ball joint 12 is changed.The curve shown by the solid line is for the conventional case, and the curve shown by the broken line is for the case where the ball joint 12 is displaced upward. In this case, the curve indicated by the dashed-dotted line is displaced downward. In the above case, the ball joint 12 has been displaced upward, so as the amount of bounce increases (as the steering angle increases at high speed), toe-in tends to occur more than before.

On the other hand, FIG. 7 is a characteristic diagram showing changes in the turning angles of the inner and outer wheels when the ball joint 12 is shifted in the longitudinal direction of the vehicle. The curve shown by a solid line is the conventional case, the curve shown by a dashed dotted line is a case where the vehicle is shifted to the front side (in the direction of travel), and the curve shown by a broken line is a case where the curve is shifted to the opposite side. Since the above case is a case where the vehicle deviates in the traveling direction, the difference in turning angle between the inner and outer wheels tends to be smaller than in the past. Therefore, in the above case, understeer is reduced in maneuverability, and turning performance is improved compared to the conventional vehicle.

The suspension geometry can be changed depending on the amount of eccentricity, the initial position of the ball joint 12, the shape of the guide groove 16, etc., and can be set to suit various purposes.

(Effects of the Invention) As detailed above, according to the present invention, the position of the ball joint relative to the tie rod can be changed in accordance with the steering angle of the steering wheel. This makes it possible to change the toe-in change characteristics or the change characteristics of the turning angle of the inner and outer wheels in accordance with the steering angle of the steering wheel, thereby improving the turning performance of the vehicle as much as possible.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the steering device of this example, Figure 2 is a perspective view showing the gearbox broken around the pin, Figure 3 is a bottom view showing the guide groove, and Figure 4 is a steering wheel with the steering wheel to the right. A perspective view showing the direction of movement of the rack bar etc. when turning, Fig. 5 is a side view showing the displacement of the ball joint at this time, and Fig. 6 shows the amount of bounce when the height of the ball joint is changed. Toe-in characteristic diagram. Figure 7 is a characteristic diagram showing the change in turning angle of the inner and outer wheels when the ball joint is shifted in the longitudinal direction of the vehicle. Figure 8 is a partially cutaway front view of a conventional steering device. It is a diagram. 1...Gearbox, 2...Rack bar, 4...
...Tie rod, 12...Ball joint, 16
...Guide groove, j...Joint part.

Claims (1)

[Claims for Utility Model Registration] A steering device in which a rack bar is incorporated in a steering gear box so as to be relatively displaceable in the axial direction, and both ends of the rack bar are provided with joint portions that connect to tie rods, the steering device comprising: a rotating shaft that is fixed to the joint portion and is mounted such that it cannot be displaced relative to the rack bar in the axial direction and can rotate relative to the rack bar, and a pin that is fixed to the rotating shaft is engaged with the rotating shaft; a guide groove provided in the gear box that is guided by the gear box, the rotation shaft being guided by the gear box according to the relative displacement of the pin in the axial direction with respect to the gear box in accordance with the relative displacement of the rack bar in the axial direction with respect to the gear box; A steering device comprising: a guide groove having a shape for relative rotation to the shaft; and a tie rod connection portion provided in the joint portion and disposed at an eccentric position with respect to the axis of the rotation shaft.