JPH0596923A - Suspension system - Google Patents

Abstract

PURPOSE:To reduce the turning radius and to enhance the directional stability by setting the damping force of an actuator on the front wheel side so that it is softer than that on the rear wheel side when an steering angle larger than a predetermined value is detected in a condition in which ABS control is carried out. CONSTITUTION:A suspension system is composed of a steering angle sensor 15 for detecting a steering angle and sending angular data to a suspension controller 14, an ABS controller 17 for delivering an ABS control signal for preventing a wheel from being locked caused by abrupt braking, to the suspension controller 14. The suspension system controls actuators through the intermediary of the suspension controller 14 so that the damping force thereof becomes harder when a brake switch 16 delivers a turn-on signal during rectilinear running. When a steering angle larger than a predetermined value is detected in a condition in which the ABS control signal is delivered, the actuators 12 on the front side are controlled so that the damping force thereof is softer than that on the rear side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension system, which controls the damping force of an actuator in accordance with a braking operation and detects that the vehicle has made a sharp turn while ABS control is being performed. The present invention relates to a suspension system that changes the damping force of a front wheel side actuator relative to the damping force of a rear wheel side actuator.

[0002]

2. Description of the Related Art Conventionally, various suspension systems have been developed in order to improve running stability or riding comfort of a vehicle.

In this type of suspension system, an actuator having a damper structure for absorbing the vertical shock of each wheel is arranged in correspondence with each wheel according to the road surface condition, etc. It is known that the damping force of the actuator is appropriately switched between hard and soft in accordance with the control signal.

In the damping force control of such a suspension system, for example, as shown in FIG. 6, when soft control is performed so that the damping force of the actuator becomes large when the brake switch is turned on, it is shown in FIG. As described above, the front of the vehicle is in a forward leaning state, which causes a so-called nose dive phenomenon, and there is a problem that running stability is impaired.

By the way, if the frictional resistance acting between the wheel and the brake pad so as to stop the rotation of the wheel during sudden braking exceeds the frictional resistance between the wheel and the road surface, the wheel is locked. Such a locked state becomes more apparent especially on a road surface during rainfall or snowfall, a frozen road, a wasteland, and the like. Therefore, directional stability is impaired when the wheels are locked, and ABS control is known in which brake control is performed to prevent this.

According to the ABS control, the locking of the wheels is prevented, the directional stability of the vehicle is maintained, the maneuverability is ensured, and the braking force is maximized to shorten the stopping distance. It becomes possible.

However, when the damping force of each actuator becomes small at the time of sudden braking, that is, in a hard state, the turning radius becomes large and an understeer tendency tends to occur when a sudden turn is made in this state, resulting in an obstacle. There is a problem such as a delay in evacuation from the etc. (See curves R1 in Figures 3 and 4)

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to keep each damping force actuator hard to avoid the nose dive phenomenon of a vehicle and to perform ABS control at the same time during a sudden braking during straight running. When the vehicle makes a sharp turn while the vehicle is running, the damping force of the front-wheel actuator is made softer than the damping force of the rear-wheel actuator to reduce the turning radius, which can improve directional stability. To provide.

[0009]

In order to achieve the above object, the suspension system according to the present invention receives an ON / OFF signal of a brake switch as an input and controls the damping force of a damping force switching actuator arranged corresponding to each wheel. In a suspension system equipped with a suspension controller that switches appropriately, the suspension system uses a steering sensor that detects a steering angle and outputs angle information to the suspension controller, and an ABS control signal that prevents wheel locking due to sudden braking or the like. An ABS controller for outputting to the controller is provided, and when the ON signal of the brake switch is output during straight traveling, the damping force of the actuator is controlled hard via the suspension controller, and the ABS control is performed. When more than a predetermined angle of the steering angle is detected by the output state of the item, and is configured to control the soft damping force of the front wheel side actuator relative to the damping force of the rear wheel side actuator.

[0010]

When a sudden brake is applied during straight running, an ABS control signal is output to the suspension controller to prevent the wheels from being locked, and an ON signal is applied from the brake switch to the suspension controller to cause suspension controller control. Outputs an operation signal to each damping force actuator, and the damping force of the actuator is reduced to allow the suspension to travel in a hard state. In order to avoid obstacles ahead of the vehicle or when a steered curve is about to travel on a road and the steering wheel is operated and the steering angle given to the suspension controller by the steering sensor exceeds a predetermined angle, the suspension controller turns the front wheel side. A control signal for increasing the damping force of the actuator, that is, a soft state is applied, whereby the damping force of the front wheel side actuator is relatively changed with respect to the rear wheel side actuator.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 showing the overall construction of this embodiment, the vertical movement of the vehicle 11 is relaxed at a predetermined position corresponding to each wheel 10 to control the running stability or riding comfort of the vehicle. The damping force switching actuators 12 having the damper structure are arranged correspondingly.

A control signal output from the suspension controller 14 is input to the actuator 12, and the damping force of each actuator 12 is switched in accordance with this control signal in two steps, large and small, in this embodiment. Therefore, the vertical movement of the vehicle is maintained hard and soft.

The suspension controller 14 includes a steering sensor 15, a brake switch 16 and an ABS.
Controllers 17 are respectively connected, the steering sensor 15 indicates the direction of the vehicle 11, that is, the steering angle, and the brake switch 16 operates the brakes.
The ABS controller can detect the lock prevention state of each wheel 10.

The steering sensor 15 is composed of, for example, a potentiometer which outputs a steering angle as a voltage, but the present invention is not limited to this, and other known detection methods may be adopted.

The brake switch 16 is composed of a switch (not shown) for detecting the depression of the brake pedal, and the normal braking operation and the sudden braking are discriminated by the correlation between the depression amount of the brake pedal and the time. However, it is also possible to detect the voltage change.

The ABS controller is for preventing the wheel 10 from being locked, so that the frictional resistance generated between the wheel 10 and the brake pad does not exceed the frictional resistance generated between the wheel 10 and the road surface. In addition, the pressure of the brake pad is adjusted, so that the directional stability of the vehicle 11 is maintained constant in road surface conditions such as during rain and snow. When this ABS control is performed, the operation signal is the suspension controller 14
Given to.

Next, the operation of this embodiment will be described with reference to FIGS.

Now, assuming that the vehicle 11 is traveling forward,
It is assumed that the suspension controller 14 normally controls each actuator 12 in order to increase the damping force of the actuator 12 and hold the suspension softly.

In this state, as shown in FIG. 3, when sudden braking is applied at point P to avoid the obstacle 20 located in front of the vehicle 11, the suspension controller 14 outputs the output signal from the brake switch 16. Based on the above, the control signal for reducing the damping force of each actuator 12 is output, while it is determined whether or not the ABS control signal is input from the ABS controller 17. Where ABS
When the control signal is input, it is determined based on the steering angle from the steering sensor 15 whether the vehicle 11 is traveling in the turning direction. When the steering angle is less than the preset angle,
Although the suspension controller 14 still operates so as to hold the suspension hard, when a predetermined angle or more is detected and it is determined that the vehicle 11 is traveling in the turning direction, the damping force of only the front wheel actuator 12 is applied. A damping force switching signal to be increased is output to the front wheel side actuator 12.

Based on the damping force switching signal output from the suspension controller 14, the damping force is increased in the front wheel side actuator, and only the front wheel side suspension is softly held.

When the front wheel side suspension is held softly and the rear wheel side suspension is held hard, the turning radius becomes small as shown in FIGS. 3 and 4, and the turning radius is indicated by R2. As described above, it becomes possible to obtain a travel locus in which the avoidance characteristics for the obstacle 20 and the like are further improved.

Therefore, the above-described embodiment of the present invention has the following effects.

That is, when the vehicle is suddenly braked while traveling straight ahead, the suspension is held hard, so that the nose dive phenomenon can be avoided, and the running stability and the riding comfort can be maintained well and the same. When the ABS control is performed in this state, the wheels can be effectively prevented from being locked, so that the maneuverability can be ensured while maintaining the directional stability of the vehicle, and the braking force is maximized to shorten the stopping distance. be able to.

Further, the angle information from the steering sensor 15 is obtained while the ABS control is being performed.
When this exceeds a predetermined angle, turning traveling of the vehicle 11 is detected, and at this time, the suspension controller 14 is arranged to soften the damping force of only the front wheel side actuator 12.
Since it acts so as to carry out a predetermined control, the turning radius can be reduced while maintaining the directional stability of the vehicle 11, which allows the vehicle to evacuate from an obstacle in front of the vehicle more quickly, and also allows the vehicle to curve sharply. There is an effect that so-called turning of the steering wheel can be favorably maintained due to the tendency to oversteer during traveling.

Further, in order to obtain the above effect, the steering angle information and the brake switch 16 are used in this embodiment.
The suspension controller 14 is configured to perform a predetermined control by inputting the ON / OFF signal of 1) and the ABS control signal from the ABS controller 17, and does not have a complicated system configuration.

When the turning is detected during the ABS control, the damping force of the front wheel side actuator may be increased relative to the rear wheel side, and the degree thereof is finely adjusted in a plurality of steps. It is also possible. For example,
In order to perform such adjustment, the turning amount based on the steering angle is divided into a plurality of steps, and as the turning amount increases, that is, the damping force of the front wheel side suspension increases as the steering angle increases, thereby making the operation softer. Controlling is possible.

[0028]

As described above, according to the present invention,
Stability is improved by adopting a configuration in which the suspension during straight braking and the suspension during sudden braking and the suspension during sudden braking and turning are adjusted by different controls.
It is possible to maintain good riding comfort and to achieve early evacuation from an obstacle or the like.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an overall configuration of a system showing an embodiment of the present invention.

FIG. 2 is a block diagram of the embodiment.

FIG. 3 is an operation explanatory view when traveling straight ahead.

FIG. 4 is an operation explanatory view when traveling on a curved road surface.

FIG. 5 is a flow chart of the embodiment.

FIG. 6 is a timing chart of a conventional example showing the relationship between damping force switching and a brake signal.

FIG. 7 is a diagram for explaining a nose dive phenomenon of the vehicle when the damping force is switched at the timing shown in FIG.

[Explanation of symbols]

 11 Vehicle 12 Damping Force Switching Actuator 14 Suspension Controller 15 Steering Sensor 16 Brake Switch 17 ABS Controller

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 5, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

In the damping force control of such a suspension system, for example, as shown in FIG. 6, when the brake switch is turned on, the damping force of the actuator is reduced.
When the soft control is performed so as to decrease, the front of the vehicle becomes a forward leaning state as shown in FIG. 7, which causes a so-called nose dive phenomenon, which causes a problem that the running stability is impaired.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

However, when the damping force of each actuator is increased during a sudden braking, that is, when the actuator is in a hard state, the turning radius becomes large when an abrupt turn is made in this state, and an understeer tendency is caused, resulting in an obstacle. There is a problem such as a delay in evacuation from the etc. (See curves R1 in Figures 3 and 4)

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

When a sudden brake is applied during straight running, an ABS control signal is output to the suspension controller to prevent the wheels from being locked, and an ON signal is applied from the brake switch to the suspension controller to cause suspension controller control. Outputs an operation signal to each damping force actuator, and the damping force of the actuator is increased to allow the suspension to travel in a hard state. In order to avoid obstacles ahead of the vehicle or when a steered curve is about to travel on a road and the steering wheel is operated and the steering angle given to the suspension controller by the steering sensor exceeds a predetermined angle, the suspension controller turns the front wheel side. A control signal is provided to reduce the damping force of the actuator, that is, to bring it into a soft state, whereby the damping force of the front wheel side actuator is changed relative to the damping force of the rear wheel side actuator.

[Procedure correction 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

Now, assuming that the vehicle 11 is traveling forward,
It is assumed that the suspension controller 14 normally controls each actuator 12 in order to keep the suspension soft by reducing the damping force of the actuator 12.

[Procedure amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0020

[Correction method] Change

[Correction content]

In this state, as shown in FIG. 3, when sudden braking is applied at point P to avoid the obstacle 20 located in front of the vehicle 11, the suspension controller 14 outputs the output signal from the brake switch 16. Based on the above, the control signal for increasing the damping force of each actuator 12 is output, while it is determined whether or not the ABS control signal is input from the ABS controller 17. Where ABS
When the control signal is input, it is determined based on the steering angle from the steering sensor 15 whether the vehicle 11 is traveling in the turning direction. When the steering angle is less than the preset angle,
Although the suspension controller 14 still operates so as to hold the suspension hard, when a predetermined angle or more is detected and it is determined that the vehicle 11 is traveling in the turning direction, the damping force of only the front wheel actuator 12 is applied. A damping force switching signal to be reduced is output to the front wheel actuator 12.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Based on the damping force switching signal output from the suspension controller 14, the damping force is reduced in the front wheel side actuator, and only the front wheel side suspension is softly held.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

When the turning is detected during the ABS control, the damping force of the front wheel side actuator may be made smaller than that of the rear wheel side, and the degree thereof is finely adjusted in a plurality of steps. It is also possible. For example,
Order to perform such adjustments, divided into a plurality of turning amount based on the steering angle stepwise, as the amount of turning is increased, that is softer so as to reduce the damping force of the front wheel suspension as steering angle increases Controlling is possible.

Claims (1)

[Claims] 1. A suspension system comprising a suspension controller that receives a brake switch ON / OFF signal as an input and appropriately switches the damping force of a damping force switching actuator arranged corresponding to each wheel. A steering sensor that detects and outputs angle information to the suspension controller, and an ABS controller that outputs an ABS control signal to the suspension controller that prevents wheel locking due to sudden braking etc. are provided. When the output is output, the damping force of the actuator is hard-controlled via the suspension controller, and when the steering angle of a predetermined value or more is detected in the output state of the ABS control signal, the front wheel side actuation is performed. A suspension system characterized in that the damping force of the user is softly controlled with respect to the damping force of the rear wheel side actuator.