JP3200860B2 - Wishbone suspension system - Google Patents

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 device comprising an upper arm, a lower arm and a shock absorbing mechanism, wherein a wheel is suspended from a vehicle body. It relates to a suspension device.

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this type, as shown in, for example, Japanese Patent Application Laid-Open No. 62-268772, an inner end of an upper arm is assembled so as to be displaceable in a lateral direction with respect to a vehicle body. An electric actuator for driving the upper arm in the lateral direction is provided, and the actuator is controlled in accordance with the traveling state of the vehicle, thereby controlling the change of the camber angle of the wheels relative to the ground in accordance with the traveling state of the vehicle. Have been.

[0003]

Generally, it is an ideal characteristic of a suspension system that the camber angle of the wheels to the ground is always kept at zero. Therefore, when the vehicle turns, the turning outer wheel is positioned with respect to the vehicle body. It is desirable that the camber be set to a negative camber (the upper part of the wheel goes inward), and that the inner turning wheel be set to a positive camber (the upper part of the wheel open to the outer side) relative to the vehicle body. It is well known that it is desirable for the angle to be set to zero. However, in the above-described conventional apparatus, in order to control the camber change characteristics of the wheels as described above, various elements are detected as the traveling state of the wheels, and a calculation based on these elements is performed. It is necessary to control the actuator, and a detector for detecting these elements and a control device for controlling the actuator based on the detection result become complicated. SUMMARY OF THE INVENTION The present invention has been made to address the above problem, and an object thereof is to obtain an ideal camber change characteristic of a wheel with a simple configuration by controlling a camber change characteristic in conjunction with steering of a wheel. It is an object of the present invention to provide a wishbone type suspension device which can perform the above-mentioned.

[0004]

To achieve the above object, according to the Invention The features of construction of the invention according to the first aspect, the outer portion
The wheels are connected and turned about a vertical axis.
Knuckle arm that steers wheels
Connect and hang the top of the knuckle arm at the outer end
An upper arm that is connected so that it cannot rotate around a straight axis,
Connected to the body at the side end and knuckle at the outer end
Arm connecting the lower part of the arm and the lower arm
In a wishbone type suspension device that has a shock absorbing mechanism provided between the vehicle and the vehicle body and suspends the wheels on the vehicle body, a guide rail formed in a substantially arc shape is attached to a part of the vehicle body located above the inside of the wheel. with substantially horizontally fixed to a wheel side to the inner surface, the inner end of the upper arm to the bracket assembled movably on the guide rail vertical
Non-rotatably connected to the axis, the Na Tsu <br/> Kuruamu the length of the apparent A Ppaa <br/> over arm as viewed from the vehicle body rear came to be turned to steer the vehicle wheel It is designed to be shorter. Further, a structural feature of the invention according to claim 2 is that the knuckle arm according to the invention according to claim 1 is provided in a steering device and is connected to the knuckle arm at an outer end at an axial end of the tie rod. It is to be rotated by displacement. Further, a structural feature of the invention according to claim 3 is that an actuator that drives the bracket of the invention according to claim 1 and causes the bracket to move on the guide rail by itself is provided on the bracket, and the knuckle arm includes: The self-propelled bracket is rotated through the upper arm.

[0005]

According to the first aspect of the present invention, when the knuckle arm is rotated to steer the wheels, the bracket moves on the guide rail substantially in an arc and at the same time the inner end of the upper arm. Also moves with the bracket , which changes the camber change characteristics of the wheels
Is done. That is, when the vehicle turns while the wheels are steered.
Is that the inner end of the upper arm moves almost
And the apparent length of the arm seen from the back of the vehicle is short.
It becomes. On the other hand, when the vehicle is going straight, the upper arm is almost
Same arm viewed from the back because it is located extending in the lateral direction of the body
The apparent length is longer (closer to the length of the lower arm).
). This means that when turning, the wheels
The camber characteristic of the camber changes greatly,
The ground camber angle of the wheel is kept small
Means Also, when the vehicle is going straight,
Camber characteristics with small camber change, uneven road surface
The wheels are bound or rebound
This means that the ground camber angle is kept small. In addition,
In this case, the knuckle arm is rotated by being driven 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 according to claim 3. Then, the movement of the bracket is transmitted to the knuckle arm via the upper arm and rotates.

[0006]

As can be understood from the above operation description,
According to the invention according to the first to third aspects, the camber angle of the wheels is kept close to zero both when the vehicle is turning and when the vehicle is going straight by controlling the change of the camber change characteristics of the wheels. The control is performed in conjunction with the steering of the wheels, and there is no need for a device that detects the running state of the vehicle and a device that calculates the detection result, which are specially provided for controlling the camber change characteristics. It is possible to obtain an ideal camber change characteristic without complicating the control device for controlling the change.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a wishbone type suspension apparatus according to the first embodiment. In this suspension device, a wheel 10 is connected to a knuckle arm 1
1 and is suspended from the vehicle body by an upper arm 12 and a lower arm 13.

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

The upper arm 12 has an inner end connected to the vehicle body via a guide rail 15 and a bracket 16, and an outer end connected to the upper end of the knuckle arm 11 so as to be rotatable around a shaft 17. I have. The guide rail 15 includes a base 15a on a plate formed in a substantially arc shape,
An engaging portion 15b having a T-shaped cross-section is integrally formed along the base portion 15a, and a portion of the vehicle body located above the inside of the wheel 10 at the base portion 15a is substantially formed with the wheel 10 side as an inner surface. It is fixed horizontally. As shown in FIG.
As shown in FIG. 5, 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 portions 15b of the guide rail 15 . The inner end of the upper arm 12 is connected to the bracket 16 so as to be rotatable around an axis 23.

The lower arm 13 has a shaft 2 at its inner end.
The knuckle arm 11 is connected to the vehicle body so as to be rotatable around four times and is ball-joined to the lower rear end of the knuckle arm 11 at the outer end. Between the lower arm 13 and the vehicle body, a shock absorber 25 and a spring 26 constituting a shock absorbing mechanism are interposed. The lower end of the shock absorber 25 is connected to an intermediate portion of the lower arm 13 so as to be rotatable around the shaft 27, and the 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 described. When the tie rod 14 is in the neutral position and the wheels 10 are not steered, that is, when the vehicle is going straight, the upper arm 12 is substantially 3A, the apparent length of the arm 12 as viewed from the back is longer, and is closer to the length of the lower arm 13 as shown in FIG. As a result, the wheels 1
0 bounces or rebounds with respect to the vehicle body, the camber angle θ of the wheel 10 with respect to the vehicle body decreases, and in this case, the vehicle body is maintained substantially parallel to the road surface.
The ground camber angle θ of 0 is also set to a small value substantially 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 about a substantially vertical axis and the wheels 10 are steered, such as when the vehicle is turning, the knuckle arm 11 rotates. Is transmitted to the bracket 16 via the upper arm 12, and the bracket 16 moves outwardly in a substantially arc shape on the engaging portion 15b of the guide rail 15 with the rotation of the rollers 21 and 22. As a result, as shown in FIG.
When 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, for the turning outer wheel, wheel 1
Since 0 is tilted toward the vehicle body and the wheel 10 is tilted outward in the turning inner wheel, the camber angle θ with respect to the vehicle body and the roll of the vehicle cancel each other, so that the camber angle of the wheel 10 to the ground is close to zero.

As described above, according to the above-described embodiment, regardless of whether the vehicle is traveling straight or turning, the wheels 1
Since the ground camber angle of 0 is always set to a value close to zero, the camber change characteristic of the suspension device becomes close to ideal. Since the control of the camber change characteristic is performed in conjunction with the steering of the wheel 10, the control device for the camber change characteristic is simplified.

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. Thus, 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 steering amount of the wheel 10.
For example, when the vehicle is traveling straight, the kingpin axis is moved as shown in FIG.
So as to set the position K ₁ in (B), and if so at the time of turning of the vehicle to set the kingpin axis to the position K ₂ in the figure, the caster angle of the wheel 10 during straight δ
₁ and caster trail L ₁ is set larger, and since the caster angle [delta] ₂ and caster trail L ₂ at the time of turning is to be set smaller, the turning performance of the vehicle with straightness of the vehicle becomes better and better Become.

Next, instead of rotating the knuckle arm 11 according to the axial displacement of the tie rod 14 in the first embodiment, the knuckle arm 11 is made to run on the guide rail 15 by itself. A second embodiment in which is rotated will be described. In the description of the second embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The suspension device according to the second embodiment includes an electric motor 31 mounted on the bracket 16 as shown in FIG. The rotating shaft of the electric motor 31, as shown in FIG. 6, is connected to a rotating shaft 21a of the roller 21, is on the central outer periphery of the roller 21 gear 3
2 are provided. Further, rack teeth 33 are formed on the upper surface of the engagement portion 15b of the guide rail 15, and the gear 32 meshes with the teeth 33.

The rotation of the electric motor 31 is controlled by a steering state detecting 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, and the like.
The rotation angle, rotation direction, and rotation speed of the steering wheel 36 are detected, and a signal representing each detected value is output. The microcomputer 35 receives the signals from the steering state detecting device 34, determines the direction, speed and distance of the bracket 16 moving on the guide rail 15 based on the signals, and requires the necessary control signals. It outputs to the electric motor 31 for a short time to control the rotation of the motor 31. The microcomputer 34 also outputs the control signal to the other wheel.

In the second embodiment constructed as described above, when the steering wheel 36 is turned, the microcomputer 35 controls the drive of the electric motor 31 in accordance with the rotation of the steering wheel 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 turning operation of the steering handle 36, so that the knuckle arm 11 and the upper arm 12 are also turned in accordance with the turning of the handle 36, and the wheel 10 is steered. Also, in this case, the movement of the inner end of the upper arm 12 is the same as that in the first embodiment, so that the same effect as in the first embodiment is obtained.

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, so that the tie rod 14 of the first embodiment is omitted. The toe angle of the wheel 10 does not change due to the influence of the tie rod 14 at the time of bouncing or rebounding, and the straight running stability of the vehicle, the traceability of the vehicle during turning, the steering feeling, and the like are improved. Further, the space for disposing the tie rods 14 becomes unnecessary, and in a vehicle having no space, the other devices can be disposed in the unnecessary space.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an assembled state of the bracket of FIG. 1 with respect to a guide rail.

FIG. 3 is an operation explanatory diagram for explaining a change state of a camber angle of a wheel with respect to a vehicle body when the vehicle travels straight and turns.

FIG. 4 is an operation explanatory diagram for explaining a change state of caster angles and caster trails of wheels when the vehicle travels straight and turns.

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

FIG. 6 is a diagram showing an assembled state of the bracket of FIG. 5 with respect to a guide rail.

[Explanation of symbols]

Reference Signs List 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.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 3/18-3/28 B62D 7/08 B62D ^7/ 18-7/20

Claims (3)

(57) [Claims] 1. A knuckle arm connected to a wheel at an outer portion and turned about a vertical axis to steer the wheel, and a knuckle arm connected at an inner end to a vehicle body and at an outer end. An upper arm that is connected to the vehicle body so that it cannot rotate about a vertical axis, a lower arm that is connected to the vehicle body at an inner end and connects a lower portion of the knuckle arm at an outer end, and the lower arm and the vehicle body. In a wishbone type suspension device having a shock absorbing mechanism provided between the wheels and suspending the wheels on the vehicle body, a guide rail formed in a substantially arc shape is provided on a part of the vehicle body located above the inside of the wheels with the wheel side on the inner surface. And the inner end of the upper arm is attached to a bracket movably mounted on the guide rail around a vertical axis.
A wishbone connected so as not to rotate and configured such that when the knuckle arm is rotated to steer the wheels, the apparent length of the upper arm as viewed from the back of the vehicle body is reduced. Type suspension device. 2. The wish according to claim 1, wherein said knuckle arm is rotated by an axial displacement of a tie rod provided in a steering device and connected to an outer end of said knuckle arm. Bone type suspension device. 3. An actuator for driving the bracket to move the bracket on the guide rail by itself is provided on the bracket, and the knuckle arm is rotated via the upper arm by the self-running of the bracket. The wishbone type suspension device according to claim 1, wherein