JPH04287707A - Wishbone type suspension device - Google Patents

Abstract

PURPOSE:To provide the realistic camber change characteristic of a wheel with a simple structure. CONSTITUTION:In a wishbone type suspension device, a circular arc-shaped guide rail 15 is fixed to part of a vehicle body located above the inside of a wheel 10, and the inside end of an upper arm 12 is connected to a bracket 16 movably assembled to the guide rail 15. When a knuckle arm 11 is rotated to steer the wheel 10, the bracket 16 is moved on the guide rail 15. The apparent length of the upper arm 12 on the back view is shortened, the camber change of the wheel 10 is increased, thus the ground camber angle of the wheel 10 is kept small even if the vehicle body is rolled when a vehicle is turned. The apparent length of the upper arm 12 on the back view is extended near to a lower arm 13 when the vehicle straightly advances, and the ground camber angle of the wheel 10 is kept small even if the wheel 10 is vertically displaced by irregularities on the road surface.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wishbone type suspension system that includes an upper arm, a lower arm, and a shock absorbing mechanism for suspending wheels on a vehicle body, and particularly relates to a wishbone type suspension system that suspends wheels on a vehicle body, and in particular, the present invention relates to a wishbone type suspension system that includes an upper arm, a lower arm, and a shock absorbing mechanism for suspending wheels on a vehicle body. The present invention relates to a suspension device.

0002

2. Description of the Related Art Conventionally, as shown in Japanese Patent Application Laid-open No. 62-268772, this type of device has been used, for example, in which the inner end of an upper arm is assembled so as to be displaceable in the lateral direction with respect to the vehicle body. It is known that an electric actuator that drives the upper arm in the lateral direction is provided, and by controlling this actuator according to the driving condition of the vehicle, the ground camber angle of the wheel can be changed and controlled according to the driving condition of the vehicle. It is being

0003

[Problem to be Solved by the Invention] In general, the ideal characteristic of a suspension device is that the camber angle of the wheels to the ground is always maintained at zero, and for this reason, when the vehicle turns, the outer turning wheels should be kept at zero relative to the vehicle body. It is desirable that the turning inner wheels are set to negative camber (the upper part of the wheel moves inward), and that the inner turning wheel is also set to positive camber (the upper part of the wheel opens outward) relative to the vehicle body, and when the vehicle is traveling straight, the camber of both wheels relative to the vehicle body is set. It is well known that it is desirable to set the angle to zero. However, in the conventional device described above, in order to control the camber change characteristics of the wheel as described above, various elements are detected as the running state of the wheel, and calculations are performed based on these elements. , it is necessary to control the actuator, and the detector for detecting these elements and the control device for controlling the actuator based on the detection results become complicated. The present invention was made to solve the above problem, and its purpose is to control the camber change characteristics in conjunction with the steering of the wheels.
To provide a wishbone type suspension device capable of obtaining ideal wheel camber change characteristics with a simple configuration.

0004

[Means for Solving the Problems] In order to achieve the above object, the structural features of the invention according to claim 1 include a knuckle arm, an upper arm, a lower arm, and a shock absorbing mechanism to suspend a wheel on a vehicle body. In a wishbone type suspension device, a guide rail formed in an approximately arc shape is fixed almost horizontally to a part of the vehicle body located above the inside of the wheel with the wheel side facing inside, and is movable on the guide rail. This is because the inner end of the upper arm is connected to the assembled bracket. Further, a structural feature of the invention according to claim 2 is that the knuckle arm of the invention according to claim 1 is arranged in the axial direction of a tie rod provided in a steering device and connected to the knuckle arm at its outer end. The reason is that it can be rotated by displacement. Furthermore, the structural feature of the invention according to claim 3 is that an actuator is provided to drive the bracket of the invention according to claim 1 and make the bracket self-propel on the guide rail,
The knuckle arm is configured to be rotated via the upper arm by the self-propelled movement of the bracket.

[0005]

[Operation] In the invention according to claim 1 configured as described above, when the knuckle arm is rotated to steer the wheel, the bracket moves on the guide rail in a substantially circular arc, and at the same time, the inner end of the upper arm will also move with the same bracket. In this case, the knuckle arm is driven and rotated by the axial displacement of the tie rod, for example as in the invention according to claim 2, or the actuator drives the bracket as in the invention as in claim 3. However, this movement of the bracket is transmitted to the knuckle arm via the upper arm and rotated. In this way, when the wheels are steered and the vehicle turns, the inner end of the upper arm moves approximately in an arc, so the apparent length of the arm when viewed from the rear becomes shorter. On the other hand, when the vehicle is traveling straight, the upper arm extends almost horizontally to the vehicle body, so
The apparent length of the same arm when viewed from the back becomes longer (closer to the length of the lower arm). This means that when the vehicle turns, the camber change of the wheels with respect to the vehicle body increases, and even if the vehicle body rolls, the camber angle of the wheels relative to the ground remains small. Furthermore, when the vehicle is traveling straight, the camber change of the wheels relative to the vehicle body is small, which means that even if the wheels bounce or rebound due to unevenness on the road surface, the camber angle of the wheels relative to the ground is kept small.

[0006]

[Effect of the invention] As can be understood from the above explanation of the effect,
According to the inventions according to claims 1 to 3 above, the camber angle of the wheels relative to the ground is maintained close to zero both when the vehicle turns and when the vehicle is traveling straight by controlling the change of the camber change characteristics of the wheels, and also when the camber change characteristics of the wheels are changed. The control is performed in conjunction with the steering of the wheels, and it eliminates the need for a device that detects the running state of the vehicle and a device that calculates the detection results, which are specially installed to control the camber change characteristics. Close to ideal camber change characteristics can be obtained without complicating the control device for controlling the change. Further, according to each of the above inventions, since the inner end of the upper arm is located on the guide rail, the king pin axis of the wheel always passes through the center of curvature of the guide rail. As a result, if the center of curvature for each point of the guide rail is made different, the position of the kingpin axis can be changed according to the amount of wheel steering, and the caster angle and caster trail can be freely set. When the vehicle is traveling straight, the caster angle and caster trail can be increased to improve the straightness of the vehicle, and when the vehicle is turning, the caster angle and caster trail can be decreased to improve the turning performance of the vehicle.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a perspective view of a wishbone type suspension device according to the same embodiment. This suspension device connects the wheel 10 to the knuckle arm 1.
1 and is suspended on the vehicle body by an upper arm 12 and a lower arm 13.

The knuckle arm 11 has a lower outer end connected to the wheel 10 via a hub (not shown), and steers the wheel 10 in accordance with its rotation about a substantially vertical axis. The outer end of a tie rod 14 constituting a steering device is connected to the lower front end side of this knuckle arm 11 so as to be rotatable around a vertical axis, and the arm 11 rotates in accordance with the displacement of the rod 14 in the axial direction. It is designed to move.

The upper arm 12 is connected at its inner end to the vehicle body via a guide rail 15 and a bracket 16, and at its outer end is connected to the upper end of the knuckle arm 11 so as to be rotatable around an axis 17. There is. The guide rail 15 includes a base 15a on a plate formed in a substantially arc shape,
The engagement part 15b has a T-shaped cross section and is integrally formed along the base part 15a, and is attached to a part of the vehicle body located above the inner side of the wheel 10 at the base part 15a, with the wheel 10 side being the inner surface. fixed horizontally. The bracket 16 is shown in FIG.
As shown in FIG. 2, a pair of upper and lower rollers 21 and 22 are rotatably assembled, and the rollers 21 and 22 are rotatably engaged with the engaging portion 16b of the guide rail 16. The inner end of the upper arm 12 is connected to the bracket 16 so as to be rotatable about a shaft 23.

The lower arm 13 is connected to the shaft 2 at its inner end.
It is connected to the vehicle body so as to be rotatable around four rotations, and its outer end is connected to the lower rear end side of the knuckle arm 11 by a ball joint. Furthermore, a shock absorber 25 and a spring 26, which constitute a buffer mechanism, are interposed between the lower arm 13 and the vehicle body. The shock absorber 25 has its lower end rotatably connected to the intermediate portion of the lower arm 13 about a shaft 27, and its upper end supports the vehicle body. The spring 26 is interposed between the wheel side member of the shock absorber 25 and the vehicle body.

Next, the operation of the first embodiment constructed as described above will be explained. When the tie rod 14 is in the neutral position and the wheels 10 are not being steered, that is, when the vehicle is traveling straight, the upper arm 12 is moved approximately to the side of the vehicle body. As shown in FIG. 3A, the apparent length of the arm 12 when viewed from the back is long and close to the length of the lower arm 13. This prevents the wheel from moving due to unevenness of the road surface.
Even if the wheel 10 bounces or rebounds with respect to the vehicle body, the camber angle θ of the wheel 10 with respect to the vehicle body becomes small, and in this case, the vehicle body is kept approximately parallel to the road surface, so the wheel 10
The ground camber angle θ of 0 is also set to a small value approximately equal to the camber angle θ, that is, a value close to zero.

On the other hand, when the tie rod 14 is driven in the axial direction and the knuckle arm 11 is rotated around a substantially vertical axis to steer the wheel 10, as when the vehicle is turning, the rotation of the knuckle arm 11 is is transmitted to the bracket 16 via the upper arm 12, and the bracket 16 moves outward in a substantially arc shape on the engaging portion 15b of the guide rail 15 as the rollers 21 and 22 rotate. As a result, as shown in FIG. 3(B), the Atsupa arm 12 seen from the back
When the apparent length of the wheel 10 becomes shorter and the wheel 10 bounces or rebounds with respect to the vehicle body due to the roll of the vehicle body due to the turning, the camber angle θ of the wheel 10 with respect to the vehicle body becomes large. In this case, wheel 1 is the outer turning wheel.
0 is tilted toward the vehicle body, and at the inner wheel of the turn, the wheel 10 is tilted outward, so the camber angle θ with respect to the vehicle body and the roll of the vehicle body cancel each other out, and the camber angle of the wheel 10 with respect to the ground becomes close to zero.

As explained above, according to the above embodiment, the wheels 1
Since the zero ground camber angle is always set to a value close to zero, the camber change characteristics of the suspension device are close to ideal. Since the camber change characteristic is controlled in conjunction with the steering of the wheels 10, the control device for the camber change characteristic becomes simple.

Further, according to the above embodiment, since the inner end of the upper arm 12 is located on the guide rail 15, the kingpin axis of the wheel 10 always passes through the center of curvature of the guide rail 15. Thereby, if the center of curvature for each point of the guide rail 15 is made different, the position of the kingpin axis can be changed according to the amount of steering of the wheel 10. For example, when the vehicle is traveling straight, the kingpin shaft is moved as shown in Figure 4 (A) (
If the kingpin axis is set at position K1 in B) and the kingpin axis is set at position K2 in the same figure when the vehicle is turning, the caster angle δ of the wheels 10 when traveling straight is
1 and caster trail L1 are set large, and caster angle δ2 and caster trail L2 during turning are set large.
is set small, so that the straight-line performance of the vehicle is improved and the turning performance of the vehicle is also improved.

Next, instead of rotating the knuckle arm 11 according to the displacement of the tie rod 14 in the axial direction in the first embodiment, the bracket 16 is made to move on its own on the guide rail 15. A second embodiment in which the holder is rotated will be described. In the description of the second embodiment, the same parts as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

The suspension device according to the second embodiment includes an electric motor 31 assembled to a bracket 16, as shown in FIG. The rotating shaft of the electric motor 31 is connected to the rotating shaft 21a of the roller 21, as shown in FIG.
2 is provided. Furthermore, rack teeth 33 are formed on the upper surface of the engaging portion 15b of the guide rail 15, and a gear 32 meshes with the teeth 33.

The rotation of the electric motor 31 is controlled by a steering state detection device 34 and a microcomputer 35. The steering state detection device 34 includes a rotation angle sensor, a rotation direction sensor, a rotation speed sensor, etc., and detects the rotation angle, rotation direction, and rotation speed of the steering handle 36, and outputs a signal representing each detected value. The microcomputer 35 inputs each of the signals from the steering state detection device 34, determines the direction, speed, and distance at which the bracket 16 moves on the guide rail 15 based on each signal, and generates necessary control signals. The rotation of the electric motor 31 is controlled by outputting it to the electric motor 31 for a certain period of time. The microcomputer 34 also outputs the control signal to the other wheel.

In the second embodiment configured as described above, when the steering handle 36 is rotated, the microcomputer 35 drives and controls the electric motor 31 in accordance with the rotation of the steering handle 36. The driving force of the electric motor 31 is transmitted to the roller 21, and the gear 32 of the roller 21 rotates and moves on the rack teeth 33 of the guide rail 15. As a result, the bracket 16 moves on the guide rail 15 in accordance with the rotation operation of the steering handle 36, so that the knuckle arm 11 and the upper arm 12 are also rotated in accordance with the rotation of the steering handle 36, and the wheels 10 is steered. Also in this case, since the movement of the inner end of the upper arm 12 is the same as in the first embodiment, the same effects as in the first embodiment are achieved.

Furthermore, in the second embodiment, the tie rod 14 of the first embodiment is omitted by electrically rotating the knuckle arm 11 to steer the wheel 10. The toe angle of the wheel 10 does not change due to the influence of the tie rod 14 when the vehicle bounces or rebounds, and the straight-line stability of the vehicle, the traceability of the vehicle during turning, the steering feeling, etc. are improved. Further, the space for arranging the tie rod 14 is no longer required, and in vehicles with limited space, other devices can be arranged in this unnecessary space.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a wishbone suspension device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a state in which the bracket of FIG. 1 is assembled to a guide rail.

FIG. 3 is an operation explanatory diagram for explaining how the camber angle of the wheel relative to the vehicle body changes when the vehicle is traveling straight and when the vehicle is turning.

FIG. 4 is an operation explanatory diagram for explaining changes in the caster angle and caster trail of the wheels when the vehicle is traveling straight and when the vehicle is turning.

FIG. 5 is a perspective view of a wishbone suspension device according to a second embodiment of the present invention.

6 is a diagram showing a state in which the bracket of FIG. 5 is assembled to a guide rail; FIG.

[Explanation of symbols]

10... Wheel, 11... Knuckle arm, 12... Upper arm, 13... Lower arm, 14... Tie rod, 15... Guide rail, 16... Bracket, 21, 22... Roller,
25...shock absorber, 26...spring, 31...
Electric motor, 32...gear, 33...rack teeth.

Claims (3)

[Claims] Claim 1: A knuckle arm connected to a wheel at an outer side and rotated about a substantially vertical axis to steer the wheel; and a knuckle arm connected to a vehicle body at an inner end and said knuckle arm at an outer end. an upper arm connected to the upper part of the knuckle arm; a lower arm connected to the vehicle body at the inner end and connected to the lower part of the knuckle arm at the outer end; and a buffer mechanism provided between the lower arm and the vehicle body. In a wishbone type suspension device that suspends the wheels on the vehicle body, a guide rail formed in an approximately arc shape is fixed almost horizontally to a part of the vehicle body located inside and above the wheels, with the wheel side facing the inside surface. The wishbone type suspension device is characterized in that the inner end of the upper arm is connected to a bracket movably assembled on the guide rail. 2. The wish according to claim 1, wherein the knuckle arm is rotated by axial displacement of a tie rod provided in a steering device and connected at an outer end to the knuckle arm. Bone type suspension device. 3. An actuator for driving the bracket to cause the bracket to move by itself on the guide rail, and the knuckle arm is rotated via the upper arm when the bracket moves by itself. The wishbone type suspension device according to claim 1.