JPS60197413A - Suspension for automobile - Google Patents

Abstract

PURPOSE:To perform control over a toe angle so pertinently as well as to make improvements in running stability and drivability, by constituting a setting point of at least one suspension link at the body side so as to make it alterable in vertical directions according to variations in a car running state. CONSTITUTION:Each of L-shaped arms 5R and 5L (hereinafter omitting these alphabetical letters) is pivotally supported on both sides of a suspension setting block locked to a car body free of ricking motion around a shaft 3, while a lower link 9 or a suspension link is rotatably connected to a horizontal end part 7 of each arm 5. The other end of this lower link 9 is connected to the wheel side, and a plunger 15 of an actuator 13 is rotatably connected to a vertical end part 11 of the arm 5. The actuator 13 is constituted of a hydraulic cylinder and controlled at a hydraulic control circuit consisting of a pump 21, a relief valve 23, a directional control valve 25, etc. A controller 27 drives and controls the actuator 13 so as to detect a running state and actions in a car and control a variation in a toe-in direction according to this detection.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automobile suspension.

(Prior Art) Changes in toe angle in the wheels of an automobile affect steering characteristics. In this steering characteristic, if the understeering tendency is strengthened, driving stability is obtained, while when the understeering tendency is weakened, the maneuverability is improved.

For example, regarding the rear wheels, increasing bump toe-in strengthens understeering and improves driving stability, and weakening reverse bump toe-in improves maneuverability. Therefore, desired running stability and maneuverability can be obtained by appropriately changing the toe angle of the wheels.

To perform such toe angle control, for example,
As shown in Japanese Patent No. 267, the suspension geometry of the suspension device may be changed. That is, in the device disclosed in the above-mentioned Utility Model Publication, the toe angle is directly changed each time the suspension arm connected to the wheel is moved in a direction (horizontal direction) parallel to the axis of rotation of the wheel. however,
Directly changing the toe angle in this way requires a force of several 100 kg to drive the suspension arm. Furthermore, directly changing one direction in this way is undesirable because it can impair running stability.

On the other hand, it is desirable to change the steering characteristics according to the driving conditions or behavior of the vehicle. For example, when driving at high speeds, it is necessary to strengthen the understeering tendency to ensure driving stability, and when driving at low speeds, it is necessary to increase the tendency for understeering to improve maneuverability. Therefore, it is necessary to reduce the tendency for understeering. Therefore, even when changing the toe angle, it is required to control the vehicle so that desired running stability and maneuverability can be obtained based on the running state or behavior of the vehicle such as the vehicle speed.

(Object of the Invention) The object of the present invention has been made in view of the above-mentioned points, and is an object of the present invention to provide a suspension system for an automobile that can control one angle so as to obtain a desired steering characteristic based on the driving condition or behavior of the vehicle. The goal is to provide the same.

(Structure of the Invention) In the present invention, each wheel is supported by a plurality of suspension links attached to the vehicle body so as to swing in the vertical direction of the vehicle body, and the difference in the rocking locus of each link causes the wheels to The suspension of an automobile is configured to cause a toe change in the suspension link, and in order to change the rocking locus of at least one suspension link among the plurality of suspension links, the attachment point of the suspension link on the vehicle body side is moved up and down. The vehicle is characterized by comprising an actuator that changes the direction, and a controller that detects the running state or behavior of the vehicle and controls the actuator so as to control the amount of change in one direction according to the running state or behavior. That is.

(Effects of the Invention) In the automobile suspension of the present invention configured as described above, the number of at least one suspension arm on the vehicle body side is adjusted according to changes in the running condition or behavior of the vehicle.
By changing the point and changing the suspension geometry 1
ing. As a result, the locus of movement of the wheel support point when each wheel bumps or rebounds changes depending on the above-mentioned driving conditions, etc., and thereby the toe angle can be changed, making it possible to adjust the movement trajectory according to the above-mentioned driving conditions, etc. It is possible to obtain excellent driving stability and maneuverability.

Further, according to the present invention, the actual toe angle is changed using the pump force or rebound force of the wheel, and the actuator simply changes the position of the attachment point of the suspension arm on the vehicle body side. The force required to change the toe angle is 1/10 compared to the conventional device that changes the toe angle by directly steering the wheels.
It can be reduced to about 10 kg. Furthermore, compared to the case where the toe angle is directly changed, safety when an abnormality occurs in the device is improved.

(Example) Hereinafter, an automobile suspension according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First, with reference to FIGS. 1 to 3, the principle of toe change in the automobile suspension of the present invention will be explained by taking the left rear wheel as an example.

In FIGS. 1 and 2, the symbol W indicates a left rear wheel (hereinafter simply referred to as a wheel) on the ground G, and this wheel W is connected to the first and second suspension links I5 that can swing in the vertical direction. , l. Figures 1 and 2
As is clear from the figure, in this example, the first suspension link I is set longer than the second suspension link I.

The wheel side attachment points, l, Ill of the first and second suspension links L and β are arranged on the same horizontal plane as shown in FIG. The attachment point L2 of the vehicle body B. Further, this vehicle body side attachment point β2 is attached to the vehicle body B so as to be movable one step downward.

In the above configuration, when the attachment point on the vehicle body side of the second suspension link l is at the position shown by β2, the attachment point on the wheel side, ,N, at the time of a bump is as shown in FIG. The bump toe-in/rebound toe-out characteristic is obtained as indicated by the solid line in Fig. 3. From the above state, -F vehicle body side installation When the point is lowered to the position 7'21, the wheel side attachment point +, 7!+ moves to the position shown by ■2II, lII at the time of bump,
The wheel W is in the state shown by the one-dot chain line, and therefore, as shown by the one-dot chain line in FIG. 3, bump toe-in/rebound toe-out characteristics with a strong tendency for bump toe-in and rebound toe-out are obtained. On the other hand, when the above-mentioned attachment point on the vehicle body side is raised to the position of 12 □, the number I1 on the wheel side, , J, will now be bent, tsu, l, 2 when bumping.
Therefore, the bump toe-out/rebound toe-in characteristics shown by the two-dot chain line in FIG. 3 are obtained. In addition, here, the direction of bamboo toe out f is,
This can be considered as a case where bump toe-in is particularly weakened.

In the above-described configuration and operation, depending on the driving condition or behavior of the vehicle, for example, at high speed, the vehicle body side attachment point 12 of the second suspension link 1 is set to N! If it is lowered to the + position, stronger toe-in/toe-out characteristics can be obtained, thereby increasing the tendency for understeering, thereby improving driving stability.

On the other hand, at low speeds, when the car body is taken off the side of the vehicle, N1 point 7!
If it is raised to position 2, a toe-out/toe-in tendency is obtained, which weakens the understeering tendency or creates an oversteering tendency, thus improving the steering performance.

Next, with reference to FIG. 4 and subsequent figures, the suspension having the above configuration will be explained by taking a rear wheel suspension as an example.

In FIG. 4, reference numeral 1 denotes a suspension mounting base extending in the width direction of the vehicle body, and this suspension mounting base l is fixed to the vehicle body at both ends with bolts or the like.

At the front IF of the mounting base 1 in the longitudinal direction of the vehicle body, there are L-shaped arms 5R and 5L that are rotatable around shafts 3R and 3L.
is installed. A lower link 9R19L, which is a second suspension link, is rotatably connected to each horizontal end 7R17L of both arms 5R15L. This connecting portion is the vehicle body side attachment point 7!2. The other ends of the lower links 9L and 9R are respectively connected to left and right wheel sides (not shown). This connecting portion is the wheel-side attachment point 11.

On the other hand, the vertical ends 11R and I of the L-shaped arms 5R and 5L
Plungers 15R115L of the actuator 13 for vertically moving the end 7R17L of the arm are rotatably connected to the IL. Lower links 17R117L, which are first suspension links, are arranged symmetrically on the rear surface IB of the mounting base 1 so as to be rotatable at one end.
The other end of 17L is connected to a wheel (not shown).

The wheel side connection part of this lower link is the above wheel side attachment point L.
1, and the vehicle body side connection portion is the vehicle body side attachment point L2.

Next, an example of a specific structure of the actuator 13 will be explained with reference to FIG. As shown, actuator 1
3 is composed of a hydraulic cylinder, and has a central hydraulic chamber 131 and left and right hydraulic chambers 132 and 133 defined within the cylinder.
Due to the pressure difference between the pistons 15L and 15R1 provided at the bases of the plungers 15L and 15R, the plungers 15L and 15R reciprocate in the direction of the arrow.

The pressure difference between the hydraulic chambers is controlled by a hydraulic control circuit composed of a pump 21, a relief valve 23, a directional control valve 25, etc., and switching control of the directional control valve 25 is controlled by a controller 2.
7. That is, the controller 27 turns on and off the solenoid 25a of the direction control 0 valve 25 based on the detection signal supplied from the vehicle speed sensor 29, thereby controlling the direction in which oil is pumped.

Under such control, the central hydraulic chamber 131 of the hydraulic cylinder
When the pressure increases, both plungers 15L and 15R are moved away from each other. This movement is piston 1
5R+ and 151-+ are carried out until they hit the stoppers 132a and 133a outside of the hydraulic chambers 132 and 133.

As a result, the left and right L-shaped arms rotate around the shafts 3L and 3R, and their horizontal ends, lower links 9L and 9R, rotate.
The connecting portions 7L and 7R move downward by a predetermined amount.

On the other hand, when the pressure in the hydraulic chamber 131 of the hydraulic cylinder becomes lower than the left and right hydraulic chambers 132 and 133, both plungers 1
5I7.15R are moved toward each other, and both pistons 15R, 15LI are moved toward the stopper 1 in the hydraulic chamber 131.
31a. As a result, contrary to the above, the connecting portions 7L and 7R of the double-sided arms 5L and 5R move upward by a predetermined amount.

Lower link 9R, which is the second suspension link above.
The height of the vehicle body side connecting portion 19L, z2N, that is, the height of the connecting portion 7R17L may be changed to two levels at a predetermined vehicle speed, for example, as shown by vAa in FIG. It may be changed linearly according to the vehicle speed as shown in (), or it may be changed in a high-order function according to the vehicle speed as shown by the dashed line C. In the case where the position of the connection point can be adjusted in a connected manner as shown by line c, an oil retaining means is required.

In the embodiment shown in FIG. 5 above, a hydraulic cylinder was used as the actuator for ζ, but it is also possible to use a type using a screw mechanism as in the embodiment shown in FIG. 7. . An actuator using this screw mechanism has the advantage that it is easy to linearly control the height of the connection point.

In FIG. 7, a threaded portion is formed over a predetermined range on the outer peripheral surface of both plungers 15 and 1.15R, and is screwed into a sleeve nut 61. The sleeve nut 61 is rotatably supported by a support portion 65 via a hair ring 63, and is rotated by the rotational force of a motor 69 transmitted via a gear train 67. Here, the threaded portions of both plungers are provided with threads in opposite directions, so that when the sleeve nut 61 rotates, the two plungers move in opposite left and right directions. Drive control of the motor 69 is performed by the controller 27. The controller 27 is composed of, for example, a microcomputer, and has a ROM in which a table of correspondence between the position of the connecting portion and the vehicle speed is developed, and the controller 27 is configured to move the motor so that the connecting portion reaches the position determined based on the output of the vehicle speed sensor 29. 69 is controlled.

According to this embodiment configured in this way, more suitable steering characteristics can be obtained with respect to the vehicle speed.

In the explanation of the actual example above, the toe angle control was explained based on the vehicle speed, but the toe angle control 3 2 may also be performed depending on the driving state or behavior of another vehicle. For example, when driving on snowy or rough roads, it is desirable to raise the vehicle height of a vehicle equipped with a vehicle height adjustment device. At this time, it is possible to detect the vertical change in vehicle height and lower the attachment point of the suspension arm on the vehicle body. This type of control can be performed because the tendency to bump toe-in is strengthened, driving stability is improved, and road surface interference can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic rear view of a suspension link attached to a wheel for explaining the present invention in detail, FIG. 2 is a schematic plan view of the suspension link shown in FIG. 1, and FIG. A graph showing an example of a change in toe angle obtained by the suspension links shown in FIGS. 1 and 2. FIG. 4 shows a control mechanism for controlling the height position of the attachment point of the suspension link on the vehicle body side. FIG. 5 is a partial cross-sectional view showing in detail an example of the control mechanism shown in FIG. 4, particularly the actuator, and FIG. A characteristic diagram showing an example of controlling the height of the link connection portion with respect to vehicle speed. Fig. 7 is a partial cross-sectional view showing another example of the actuator. L, I2-The suspension link, 12-Vehicle side Connecting portion, 5-L-shaped arm, 7- Link connecting portion, 90-Ar link, 13-Actuator, 15-Silanger, 27-
Control circuit, 29-vehicle speed sensor. Patent applicant: Toyo Kogyo Co., Ltd. 5 System Zero Coffee 0

Claims (1)

[Claims] Each wheel is supported by a plurality of suspension links attached to the vehicle body so as to be able to swing in the vertical direction of the vehicle body, and the structure is such that a toe change occurs in the wheel due to a difference in the rocking trajectory of each link. An actuator for changing the attachment point of the suspension link on the vehicle body side in the vertical direction in order to change the rocking locus of at least one suspension link among the plurality of suspension links; A suspension for an automobile, comprising: a controller that detects a driving state or behavior of a vehicle, and drives and controls the actuator so as to control an amount of change in one direction according to the driving state or behavior.