JPH06305403A - Braking force retention device - Google Patents

Abstract

(57) [Summary] [Purpose] The brake hydraulic pressure that is depressed when it is detected that the gear is in the neutral state or the clutch disengaged state when the vehicle is stopped is automatically retained, and the brake hydraulic pressure is automatically detected when the vehicle is started With respect to the braking force holding device to be released to 1, the driver is informed and warned in advance of how long the braking hydraulic pressure at that time can maintain the stopped state. [Configuration] The minimum hydraulic pressure for maintaining the stopped state is calculated from the inclination angle and the load in the braking force holding state, and the stop-holdable time with the passage of time is calculated from the difference between this minimum hydraulic pressure and the current brake hydraulic pressure, and is displayed and output. If necessary, an alarm is issued before the stop-maintainable time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force holding device,
In particular, the present invention relates to a braking force retaining device that automatically retains a brake hydraulic pressure that is depressed under a certain condition and automatically releases the brake hydraulic pressure when a departure state is detected.

[0002]

2. Description of the Related Art When a vehicle stopped on an uphill road is started, the brake hydraulic pressure (braking force) is maintained until the clutch is engaged by integrating output signals from various sensors provided on the vehicle. A braking force holding device designed to do so has been developed and researched so that the vehicle can be smoothly restarted on an uphill road without requiring a high degree of skill.

FIG. 5 schematically shows a well-known braking force holding device, in which 1 is a neutral switch or clutch switch, 2 is a vehicle speed sensor, and 3 is a vehicle speed sensor.
Is a brake switch, 4 is a controller for inputting the output signals of these switches 1, 3 and sensor 2, 5 is a brake pedal, 6 is a master cylinder linked with this brake pedal 5, and 7 is brake oil from this master cylinder 6. ON / OFF by the output signal from the controller 4
An electromagnetic check valve for holding braking force (hereinafter referred to as an HSA valve) that controls OFF (opening / closing), 8 is a wheel cylinder for generating a braking force by applying brake fluid from the HSA valve 7 to a wheel 9 of the vehicle. , And 10 are buzzers that generate an alarm signal according to an output signal from the controller 4.

In such a braking force holding device, the HS
The condition in which the A valve 7 is ON (brake hydraulic pressure holding state = braking force holding state) is that the neutral switch 1 indicates the gear neutral state (or the clutch switch 1 indicates the clutch disengaged state), and the vehicle speed sensor Indicates that the vehicle speed is substantially zero and the vehicle is in a stopped state, and the brake switch 3 indicates that the brake pedal 5 is stepped on.

When the controller 4 determines that the above braking force holding conditions 1 to 3 are satisfied, the HSA valve 7 is turned on.
N, the current brake oil pressure on the brake pedal 5 depressed by the driver is not returned from the wheel cylinder 8 to the master cylinder 6, and the wheel 9 is held so as not to rotate.

Further, when it is determined that any one of the above braking force holding conditions (1) to (5) is released, the controller 4 turns off the HSA valve 7 and determines that the wheel cylinder 8 is about to shift to the starting state. The brake fluid is returned to the master cylinder 6 to release the braking state of the wheel 9.

On the other hand, in the HSA valve 7, the brake hydraulic pressure gradually leaks over time. Therefore, H
When a certain time or more has elapsed after the SA valve 7 was turned on by the controller 4 and was in the braking force holding state, the buzzer 10 was operated under the prediction that the brake hydraulic pressure would have dropped to a dangerous value. The driver is given a warning (Japanese Patent Laid-Open No. 64-60460).

[0008]

As described above, in the prior art, it is not known how long the vehicle can be kept stopped after the HSA valve is activated and the foot is released from the brake pedal. Since the alarm is set by setting the time, if the HSA valve is operating with the brake hydraulic pressure at the limit of stopping, the vehicle may start moving earlier than the alarm sounds, and on the other hand, There was a problem that an alarm was issued even though there was sufficient brake hydraulic pressure.

Therefore, the present invention automatically holds the brake hydraulic pressure depressed when it is detected that the gear is in the neutral state or the clutch disengaged state when the vehicle stop state is detected,
In a braking force holding device that automatically releases the brake hydraulic pressure when a departure state is detected, it is possible to notify the driver in advance how long the brake hydraulic pressure at that time can maintain the stopped state. To aim.

[0010]

In order to achieve the above object, a braking force holding device according to the present invention comprises means for detecting a value of brake hydraulic pressure, inclination angle detecting means, load detecting means and display means. And a minimum hydraulic pressure capable of maintaining a stopped state is calculated from the inclination angle and the load, and a stop-holdable time is calculated according to a hydraulic pressure decrease characteristic over time from a difference between the current brake hydraulic pressure and the minimum hydraulic pressure, and the display means is displayed. And a control means for outputting.

Further, according to the present invention, the control means outputs an alarm signal when the stop holdable time decreases with time, and when the brake oil pressure decreases to an alarm generation oil pressure higher than the minimum oil pressure. It can also occur.

[0012]

In the present invention, when the control means detects that the gear is in the neutral state or the clutch is disengaged at the time of detecting the stop state, the hydraulic pressure detecting means detects the brake hydraulic pressure depressed at that time. .

Then, the control means calculates the minimum brake hydraulic pressure required to maintain the stopped state from the inclination angle detected by the inclination angle detection means and the load (load) detected by the load detection means.

Further, the difference between the above-mentioned current brake hydraulic pressure and the calculated minimum hydraulic pressure for maintaining the vehicle stopped state is obtained, and the current vehicle stopped state is determined based on the hydraulic pressure reduction characteristic which decreases from the difference over time. It is calculated whether it is possible only for the time of the order and output it to the display means.

As a result, the driver can recognize the restable time and can feel a sense of security.

Further, the control means can also issue an alarm when a time corresponding to the brake oil pressure at which the alarm for alarming should be issued, which has decreased with time and has been stopped, can be issued. If the vehicle may start moving, the driver can be alerted in advance.

[0017]

1 shows an embodiment of a braking force holding device according to the present invention. In this embodiment, in addition to the conventional example of FIG. 5, a controller 4 is provided between an HSA valve 7 and a wheel cylinder 8. Brake oil pressure sensor 11 which gives a detection signal to
Is provided, and an inclination angle sensor 12 as an inclination angle detecting means and a load sensor 13 as a load detecting means are provided so that output signals of these sensors are given to the controller 4. Further, a display 14 is provided so that the vehicle stop holdable time is displayed by an output signal from the controller 4 as a control means.

FIG. 2 shows a flow chart of a control program stored and executed in the controller 4 shown in FIG. 1. Hereinafter, FIG. 2 and a memory map (not shown) built in the controller 4 will be described. The operation of the embodiment shown in FIG. 1 will be described with reference to FIGS.

First, the controller 4 reads the output signals of the switches 1, 3 and the sensors 2, 11, 12, 13 (step S1).

Then, the controller 4 determines whether or not the braking force holding condition is satisfied, that is, whether the gear is in the neutral state or the clutch state and the brake pedal 5 is depressed and the vehicle is stopped. The HSA valve 7 is turned ON / OFF by making a determination from the output signal of the same as in the conventional example.

As a result, the flow chart of FIG. 2 is ended when the HSA valve is turned off (braking force holding state), but when the HSA valve 7 is controlled to be turned on (braking force holding state). In consideration of the inclination angle K indicated by the output signal of the inclination angle sensor 12 and the load J indicated by the output signal of the load sensor 13, the hydraulic pressure P1 (K, J) is calculated from the vehicle stop holding hydraulic pressure search map shown in FIG. Search and read (step S3).

That is, in the search map of FIG. 3, the load J is plotted on the horizontal axis and the inclination angle K is plotted on the vertical axis, and the minimum brake hydraulic pressure P1 capable of maintaining the stopped state corresponding to both is provided.
Search for (K, J). Therefore, as the slope and the load increase, the minimum hydraulic pressure for holding the vehicle increases.

The hydraulic pressure P1 (K, J) required to hold the vehicle stopped in this way is the inclination angle K and the load J of the present vehicle.
Since it is the lowest brake oil pressure required to maintain the vehicle stopped state, the maximum brake oil pressure by the master cylinder 6 (not particularly shown in the figure) is changed to the lowest brake oil pressure P1 (K, J). ) Is calculated from the hydraulic pressure leak characteristic map shown in FIG. 4 (step S4).

The hydraulic pressure P when the braking force is maintained
Since c is given to the controller 4 from the output signal of the oil pressure sensor 11, the oil pressure leak time t3 from the maximum brake oil pressure by the master cylinder 6 to this current oil pressure Pc is obtained from the map of FIG. 4 as well (step S5). ).

Then, the time difference tn = t1-t3 between the times t3 and t1 obtained above is calculated (step S6).

This time difference tn indicates the time during which the vehicle stop state can be maintained, and it is determined whether this vehicle stop retention time tn is smaller than the optimum time tw for issuing an alarm (step S7).

The time tw at which this warning is issued is slightly larger than the above-mentioned minimum vehicle stop holding oil pressure P1 (K, J), and indicates the time to reach a brake oil pressure suitable for giving a warning to the driver, and tn> When it is tw, the process proceeds to step S9, and an output signal for displaying the time difference tn on the display 14 is generated.

On the other hand, when it is determined that tn≤tw, it is determined that the brake oil pressure is decreasing and the vehicle is in a dangerous state where the stopped state cannot be maintained. Is generated (step S
Along with step 8), the time difference tn is also displayed on the display device 14 (step S9).

[0029]

As described above, according to the braking force holding device of the present invention, the minimum hydraulic pressure for maintaining the stopped state is calculated from the inclination angle and the load in the braking force holding state, and this minimum hydraulic pressure and the present Since it is configured to calculate and display the vehicle stop hold time with the passage of time from the difference in the brake hydraulic pressure, it is possible to show the driver how much time the vehicle can be stopped afterwards, giving the driver a sense of security. .

Further, since it is possible to issue an alarm when the brake hold hydraulic pressure decreases to an alarm generation hydraulic pressure higher than the above-mentioned minimum hydraulic pressure when the vehicle holdable time elapses, in this case, the driver is started before the vehicle starts to move. Can be alerted to.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a braking force holding device according to the present invention.

FIG. 2 is a flow chart diagram of a control program stored and executed in a controller in the braking force retaining device according to the present invention.

FIG. 3 is a diagram showing a search map of vehicle stop holding hydraulic pressure stored in a controller in the braking force holding device according to the present invention.

FIG. 4 is a graph showing a leak characteristic map of a brake hydraulic pressure stored in a controller in the braking force holding device according to the present invention.

FIG. 5 is a block diagram showing a conventional technique.

[Explanation of symbols]

 1 Neutral / Clutch Switch 2 Vehicle Speed Sensor 3 Brake Switch 4 Controller 5 Brake Pedal 7 Electromagnetic Check Valve (HSA Valve) for Holding Braking Force 8 Wheel Cylinder 9 Wheel 10 Buzzer 11 Hydraulic Sensor 12 Tilt Angle Sensor 13 Load Sensor 14 Indicator In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A control system for automatically retaining the brake hydraulic pressure that is depressed when it is detected that the gear is in a neutral state or a clutch disengaged state when a vehicle stop state is detected, and automatically releases the brake hydraulic pressure when a vehicle start state is detected. In the power retention device, means for detecting the value of the brake hydraulic pressure, inclination angle detection means, load detection means, display means, and the minimum hydraulic pressure capable of maintaining the stopped state from the inclination angle and the load, A braking force holding device comprising: a control unit that calculates a vehicle stop holdable time according to a hydraulic pressure reduction characteristic over time based on a difference between a current brake hydraulic pressure and the minimum hydraulic pressure and outputs the calculated vehicle stop holding time to the display unit. 2. The control means generates an alarm signal when the vehicle stop holdable time decreases with time and a time point at which the brake oil pressure decreases to an alarm generation oil pressure higher than the minimum oil pressure has elapsed. The braking force holding device according to claim 1, wherein: