JPH0596924A - Suspension system - Google Patents

Abstract

PURPOSE:To provide a suspension control system which copes with abrupt braking operation and ABS operation. CONSTITUTION:A suspension system is composed of a suspension controller 14 which receives turn-on and-off signals from a brake switch and delivers a predetermined control signal to actuators for damping the vertical motions of wheels, an ABS controller 17 which delivers such data that the wheels is prevented from being locked, to the suspension controller 14. The suspension controller always delivers a signal for decreasing the damping forces of the actuators so as to hold the suspension soft, and delivers a signal for increasing the damping force so as change over the suspension into a hard condition when the brake switch 16 detects an abrupt braking operation. Further, when an ABS operating signal is delivered in this condition, the suspension controller 14 delivers a control signal for changing over the damping force of the actuators 12 on the front side into a condition in a decreased condition.

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 by following a braking operation, and when the ABS control signal is output to a suspension controller, the damping force of a front wheel side actuator. The present invention relates to a suspension system that changes 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, when the wheels are locked, the directional stability is impaired and the braking distance is extended. Therefore, 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. It is an object of the present invention to provide a suspension system in which the damping force of the front wheel side actuator is made softer than the damping force of the rear wheel side actuator to reduce the turning radius when it is being performed, thereby improving the directional stability.

[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 including a suspension controller that switches appropriately, the suspension system is an AB that prevents the wheels from being locked due to sudden braking or the like.
A that outputs the S control signal to the suspension controller
It is equipped with a BS controller, which controls the damping force of each actuator via the suspension controller when the ON signal of the brake switch is output during straight running, and when the ABS control signal is output in the same state, the front wheels The damping force of the side actuator is softly controlled with respect to the damping force of the rear wheel side actuator.

[0010]

When the sudden braking is applied during straight running, an ON signal is given from the brake switch to the suspension controller, and the suspension controller outputs an operation signal to each damping force actuator, and the damping force of the actuator is reduced to reduce the suspension force. Allows to run in hard condition. When the ABS control signal is given to the suspension controller, the suspension controller outputs a control signal for increasing the damping force of only the front wheel actuator to the front wheel 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.

A brake switch 16 and an ABS controller 17 are connected to the suspension controller 14 so that the brake switch 16 can detect the operation of the brake and the ABS controller can detect whether the wheels 10 are locked.

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. 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 pressing amount of the brake pad is adjusted and the like, whereby the directional stability of the vehicle 11 is maintained constant in a road surface condition such as during rain or snow. When this ABS control is performed, its operation signal is given to the suspension controller 14.

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 the brake is suddenly applied at the point P to avoid the obstacle 20 located in front of the vehicle 11, the suspension controller 14 outputs an ON signal from the brake switch 16. On the other hand, a control signal for reducing the damping force of each actuator 12 is output on the basis of
It is determined whether the ABS operation signal is input from the BS controller 17. Here, when the ABS operation signal is input, the suspension controller 14 outputs to the front wheel side actuator 12 a damping force switching signal for increasing the damping force of only 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 so that only the front wheel side suspension is softly held.

When the front wheel side suspension is held soft 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 characteristic with respect to the obstacle 20 and the like is further improved.

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

That is, during sudden braking during straight running, since the suspension is held hard, it is possible to avoid the nose dive phenomenon and maintain good running stability and riding comfort. 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 suspension controller 1 is designed to soften the damping force of only the front wheel side actuator 12.
4 acts so as to perform a predetermined control, the turning radius can be reduced while maintaining the directional stability of the vehicle 11, and the evacuation from an obstacle in front can be performed earlier.
There is an effect that so-called turning of the steering wheel can be favorably maintained due to the tendency of oversteering during traveling on a sharply curved road surface.

Further, in order to obtain the above-mentioned effect, in the present embodiment, only the ON / OFF signal of the brake switch 16 and the ABS actuating signal from the ABS controller 17 are input to the suspension controller 14 to perform a predetermined control. Therefore, it does not have a complicated system configuration.

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 may be finely adjusted in a plurality of steps. .. For example, in order to perform such adjustment, it is possible to divide the speed decrease amount due to sudden braking into a plurality of steps and to increase the damping force of the front wheel side suspension as the decrease amount increases, thereby performing a softer control. Conceivable.

[0027]

As described above, according to the present invention,
It is possible to maintain good running stability and riding comfort by adopting a configuration in which the suspension for sudden braking during straight running and the suspension for sudden braking and during ABS operation are adjusted according to the traveling conditions by different controls. At the same time, there is an effect that early evacuation from obstacles and the like can be realized and that a braking distance can be expected to be shortened.

[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 16 Brake Switch 17 ABS Controller

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[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 the sudden braking is applied during straight traveling, an ON signal is given from the brake switch to the suspension controller, and the suspension controller outputs an operation signal to each damping force actuator, and the damping force of the actuator is increased to increase the suspension force. Allows to run in hard condition. When the ABS control signal is given to the suspension controller, the suspension controller outputs a control signal for reducing the damping force of only the front wheel side actuator to the front wheel side actuator.

[Procedure correction 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

In this state, as shown in FIG. 3, when the brake is suddenly applied at the point P to avoid the obstacle 20 located in front of the vehicle 11, the suspension controller 14 outputs an ON signal from the brake switch 16. On the other hand, a control signal for reducing the damping force of each actuator 12 is output on the basis of
It is determined whether the ABS operation signal is input from the BS controller 17. Here, when the ABS operation signal is input, the suspension controller 14 outputs to the front wheel side actuator 12 a damping force switching signal for reducing the damping force of only the front wheel side actuator 12.

[Procedure amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0020

[Correction method] Change

[Correction content]

On the basis of 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 6]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

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 may be finely adjusted in a plurality of steps. .. For example, in order to make such adjustment, it is possible to divide the speed decrease amount due to sudden braking into a plurality of steps and to reduce the damping force of the front wheel side suspension as the decrease amount increases, thereby performing a softer control. Conceivable.

Claims (1)

[Claims] 1. A suspension system provided with a suspension controller which inputs ON and OFF signals of a brake switch and appropriately switches the damping force of a damping force switching actuator arranged corresponding to each wheel, wherein the suspension system is a sudden brake or the like. It is equipped with an ABS controller that outputs an ABS control signal to prevent wheel locking based on the suspension controller, and when the ON signal of the brake switch is output during straight running, the damping force of each actuator is controlled hard via the suspension controller. And ABS in the same state
A suspension system characterized in that when a control signal is output, the damping force of the front wheel side actuator is softly controlled with respect to the damping force of the rear wheel side actuator.