JPS6082423A - Sinking preventing apparatus on brake application for car - Google Patents

Abstract

PURPOSE:To prevent the deterioration of drive feeling due to brake application in the slow traveling on a rough road by increasing the damping force of a shock absorber only the time when brake is applied sharply when the speed of a car exceeds a prescribed value. CONSTITUTION:When the first step-in switch 10 is closed by stepping-in a brake pedal, the first stepping-in signal is output into a microcomputer 16. Further, when the second step-in switch 12 is closed by stepping-in the brake pedal further, the second step-in signal is output into the microcomputer 16. When the difference between the first and the second step-in signals is shorter than a set value, it is judged that a car is in sharp brake state, and a signal is input into a driving circuit 26 from the microcomputer 16, and the damping force of a shock absorber is increased. When the car-speed signal supplied from a car-speed sensor 20 is smaller than a standard value, formation of the slow traveling state is judged, and no output is transmitted into a driving circuit 26.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for preventing sinking when a vehicle is suddenly braked, and particularly an improvement that prevents sinking by temporarily increasing the damping force of a hydraulic shock absorber when a vehicle is suddenly braking. This is related to the equipment used.

1st doubt JLJt When a running vehicle is suddenly braked, a so-called nose dive phenomenon occurs in which the vehicle body sinks forward, causing a deterioration in the ride comfort and handling stability of the vehicle. It is known that such a sinking phenomenon is caused by the characteristics of the vehicle's suspension mechanism.

As is well known, the suspension of a vehicle has a mechanism that uses a hydraulic shock absorber, and by using this alone or in combination with other springs, a vehicle suspension with excellent ride comfort and maneuverability can be obtained. −It becomes possible to

A typical hydraulic shock absorber includes a hydraulic piston interposed between the vehicle body side and the wheel side, and its damping force is always kept constant under certain conditions. That is, the damping force is normally determined by the flow cross-sectional area of an orifice that flows through two hydraulic chambers separated by a piston, and in conventional devices, the flow cross-sectional area of this orifice is constant. , the damping force under certain conditions was always kept constant.

However, with such a constant damping force, it is not necessarily possible to achieve an optimal shock absorption effect when the vehicle is actually running, and according to the results of recent vehicle running experiments, the shock absorber is It has been concluded that it is preferable to vary the damping force.

In particular, the constant damping force of the shock absorber mechanism mentioned above is normally set to suit when driving at a constant speed, so during sudden braking, the damping force cannot support the inertia of the vehicle body. There was a drawback that the above-mentioned sinking occurred.

In order to eliminate these drawbacks, in recent years, electromagnetic valve devices have been incorporated into hydraulic shock absorbers, and by exciting and driving this electromagnetic valve device, the flow cross-sectional area of the orifice is variably controlled, and the damping force of the shock absorber is adjusted. things are being done.

In this type of device, a plunger sliding groove is provided in a direction substantially perpendicular to the flow path of the orifice in the orifice that flows through the two hydraulic chambers separated by the piston, and the plunger slide groove is provided within the sliding groove. The plunger inserted into the solenoid is slid by controlling the energization of the solenoid, thereby variably controlling the flow cross-sectional area of the orifice and adjusting the damping force of the shock absorber.

Therefore, according to this type of improved device, when braking a vehicle, the damping force of the shock absorber can be increased by narrowing the flow cross-sectional area of the orifice by driving the electromagnetic valve device. This can reliably prevent the vehicle from sinking when braking.

However, in this type of device, since vehicle braking is detected by depressing the brake pedal, if the brake is operated while driving slowly on a rough, uneven road, each time the electromagnetic valve is activated. There is a problem in that the driving of the device increases the damping force of the shock absorber, resulting in extremely poor ride comfort.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to prevent the damping force of the shock absorber from becoming too great due to brake operation during slow driving on rough roads, and to improve the vehicle performance. To provide a sinking prevention device when braking a vehicle, which can increase the damping force of a shock absorber only when braking suddenly.

Structure of the Invention In order to achieve the above object, the present invention includes an electromagnetic valve device that is incorporated into a hydraulic shock absorber and changes the flow cross-sectional area of an orifice, and drives the electromagnetic valve device when braking the vehicle to increase the flow. A sinking prevention device during vehicle braking that controls the cross-sectional area to be narrow and increases the damping force of a shock absorber, comprising: a vehicle speed sensor that detects vehicle speed; a depression speed detection means that detects the depression speed of a brake pedal; the vehicle speed sensor; and a control means for detecting the braking operation state of the vehicle based on the detection signal from the depressing speed detection means and outputting a drive signal to the electromagnetic valve device, and the shock absorber is activated only when the vehicle is suddenly braked at a speed exceeding a predetermined speed. It is characterized in that the damping state of is changed from a soft state to a rigid state.

Embodiment FIG. 1 shows a block configuration of an apparatus for preventing sinking during braking of a vehicle according to the present invention.

In this embodiment, the sudden braking operation state of the vehicle is detected by a depression speed detection means that detects the depression speed of the brake pedal. That is, in this embodiment, the first depression switch 1 is located at the first depression position of the brake pedal.
0 is stepped, and a second depression switch 12 is provided at a depression position of 12 further depressed from the first depression switch position.

When the brake pedal is depressed, the first depression switch 10 is closed, and a first depression signal is output to the microcomputer 16 via the first buffer circuit 14. Further, when the brake pedal is further depressed and the second depression switch 12 is opened, a second depression switch signal is outputted to the microcomputer 16 via the second buffer circuit 18.

In this embodiment, the microcomputer 16 determines whether the vehicle is in a sudden braking state based on the output time difference between the first depression switch signal and the second depression switch signal.

In other words, the microcomputer 16 contains the first and second
A set value for the difference in opening time between the two depression switches 10 and 12 is given, and therefore, if the time difference between the output signals from both the switches 10 and 12 is shorter than this set value, it is determined that the brake is in a sudden braking state.

On the other hand, if the time difference between the output signals from both switches 10 and 12 is longer than the set value, it is not determined that there is a sudden braking state.
This is determined to be a brake operation state that occurs during normal vehicle driving.

On the other hand, in this embodiment, a vehicle speed sensor 20 for detecting the running speed of the vehicle is provided.
The detection signal from 0 and the Zunawara vehicle speed signal are supplied to the microcomputer 16 via the pulse shaping circuit 22.

In this embodiment, a drive signal is output to the electromagnetic valve device based on the depression switch signal and vehicle speed signal from both the switches 10, 12.

That is, the microcomputer 16 is provided with set values for the first and second depression switch signals as described above, and if the signal difference from both switches 10 and 12 is shorter than the set value, the vehicle The microcomputer 16 outputs a signal output command to the drive circuit 26, and an excitation voltage is applied to the solenoid 24 of the electronic valve device.

In this case, in consideration of the fact that sudden braking operations of the brake pedal are usually performed frequently when driving slowly on rough, uneven roads, in this embodiment, sudden braking operations of the brake pedal are carried out when driving slowly. Even if this is done, the output of the drive command signal from the microcomputer 16 to the drive circuit 26 is limited.

That is, a vehicle speed reference value is set in the microcomputer 16, and if the vehicle speed signal from the vehicle speed hinter 2o is smaller than the vehicle speed reference value, it is determined that the vehicle is in a slow driving state and the drive command signal is not output to the drive circuit 26. The drive command signal is output only when the vehicle is stopped and the vehicle speed signal exceeds the vehicle speed reference value.

Therefore, according to this embodiment, the excitation action of the solenoid 24 is applied only to uJ when it is determined that the vehicle is in a sudden braking state based on the first and second depression switch signals, and the vehicle is determined to be in a steady running state. This increases the damping force of the shock absorber.

As described above, in this embodiment, when J5 is applied to sudden braking during steady running of the vehicle, the magnitude of the damping force of the shock absorber is increased, and it is possible to reliably prevent J3G from sinking when the vehicle is braked.

On the other hand, this damping force increasing effect must be canceled by the time the vehicle runs again in order to optimize the ride comfort. For this reason, in this embodiment, a delay circuit 28 is provided in the microcomputer 16, and when the first depression switch 1o is released, that is, the depression of the brake pedal is activated by the first depression switch 1o. The output of the drive command signal to the drive circuit 26 is canceled after a predetermined period of time has elapsed since the return exceeded 10. Therefore, when the vehicle is started to run again after braking due to the action of this delay circuit 28, the damping force of the shock absorber is returned to the steady damping horn, thereby preventing the deterioration of the ride comfort during running of the vehicle. becomes possible.

FIG. 2 shows a time chart of the device of the present invention, and FIG. 3 shows a flowchart 1 of the device of the present invention. Detailed explanation of.

First, when starting the vehicle, the SPT counter, which counts the time difference between the brake pedal depression switch signals in order to determine the brake pedal depression speed, and the delay counter, which counts the output time of the return drive signal to the electromagnetic valve, each reach zero. Set. Then, if the desired 1-m5 processing is determined and Tms processing, that is, 4ms processing is performed, then it is determined whether or not the delay counter is zero, and if the delay counter is zero, the brake If it is determined whether the first pedal switch 10 of the pedal is on or off, and the first pedal switch signal 100 from the first pedal switch 10 is output, then the second pedal switch 12 is output. 2 pedal switch signal 1
01 signal output is determined, and in this embodiment, the first
The time difference between the second depression switch signal and the second depression switch signal is determined by the timer count value.

On the other hand, it is determined whether the vehicle is in a slow driving state or a steady driving state based on the vehicle speed signal from the vehicle speed sensor 20. For example, if the steady driving state is determined and tc, the time difference between the two switch signals 10.0.101 is determined. A comparison judgment is made between the determined brake depression speed and the set value of the brake depression speed, and the count value of the brake depression speed is set to 1.
If it is smaller than 10, it is determined that the vehicle is braking, and a drive signal is sent to the electromagnetic valve device, that is, the solenoid 24.
An excitation signal is supplied to the shock absorber to increase the damping force of the shock absorber.

The supply of the excitation signal to the solenoid 24 is continued for a predetermined delay time after the supply of the first depression switch signal 100 is stopped, that is, when the brake pedal is returned beyond the first depression switch 10. When this delay of one hour has elapsed, the solenoid 2
The output of the excitation signal to the shock absorber 4 is stopped, and the damping state of the shock absorber is changed from stiff to soft, that is, returned to a steady damping force.

In a3 and a5 of this embodiment, even if the first depression switch signal 100 from the brake pedal is output, the signal 1 of the second depression switch 12 lJI et al.
01 is not output, and both switch signals 100
．． Even if 101 is output, the drive signal is not output to the electromagnetic valve device if the vehicle speed is in a slow driving state.

d3, in the device u of this embodiment, the brake pedal
Play 4: Detecting the pedal depression speed using a brake stroke switch having the characteristics shown in Figure 4. is also possible.

As described in detail, according to the present invention, the damping force of the shock absorber is increased only during sudden braking during steady driving, and it is possible to prevent the vehicle from sinking during sudden braking. becomes.

Further, according to the device of the present invention, when the vehicle is in a slow driving state,
In this case, the damping horn of the shock absorber is not increased, so deterioration of ride comfort can be prevented.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the sinking prevention device according to the present invention that pulls c151 during vehicle braking, Fig. 2 is a time chart 17 diagram of the device of the present invention, and Fig. 3 is a flowchart 1 of the device of the present invention. FIG. 4 is a characteristic diagram of a brake stroke switch for detecting brake depression speed used in another embodiment of the device of the present invention. 10... first press switch, 12...
2nd pedal switch, 16... microcomputer, 20... vehicle speed sensor, 26... solenoid. Agent Patent attorney Kenji Yoshida (1 other person) Figure 1 Figure 4 1 Figure 2

Claims (1)

[Scope of Claims] (1) An electromagnetic valve device is incorporated in a hydraulic shock absorber to vary the flow cross-sectional area of the orifice, and the electromagnetic valve device is driven to narrow the flow cross-sectional area when the vehicle is braked. In a sinking prevention device during vehicle braking that greatly exceeds the damping force of a shock absorber, the vehicle speed sensor detects the vehicle speed, the depression speed detection means detects the depression speed of the brake pedal, and the vehicle speed sensor and the depression speed detection means include: The damping state of the shock absorber is controlled only when the 11 cars are suddenly braked while exceeding a predetermined speed. A device for preventing sinking during braking of a vehicle, characterized by changing from a soft state to a rigid state. (2. In the device described in claim (1), the depression speed detection means comprises a depression switch provided at the first depression position and the second depression position of the brake 1 pedal, and A sinking prevention device during vehicle braking, characterized in that the depression speed of the brake pedal is detected based on the difference in opening time between a switch in a depressed position and a switch in a second depressed position. (3) Claim (2) In the device J3, when the off state of the switch in the first depressed position is maintained for a predetermined period of time, a return drive signal is output from the control means to the electromagnetic valve device, and the damping state of the shock absorber changes from the rigid state to the soft state. A sinking prevention device when braking a vehicle, characterized in that it is returned to its original position.