JP2000025590A - Parking brake safety device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parking brake safety device capable of preventing an auxiliary parking brake means from being mistakenly operated by the pulse signal to be outputted by a wheel speed sensor by the effect of disturbance noise. SOLUTION: In a parking brake safety device 1 to operate an auxiliary parking brake means 23 according to the output of the pulse signal of a wheel speed sensor 11 so as to stop a vehicle when the vehicle is started when it is parked, only the pulse signal to be judged to indicate the acceleration not more than the specified value only when the pulse signal is outputted from a wheel speed sensor 11 in a condition where the vehicle is judged in a parked condition by an acceleration judging means 26 is outputted to a pulse signal judging means 22, and the auxiliary parking brake means 23 is operated when the pulse signal judging means 22 judges that the pulse number reaches the specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parking brake safety device for automatically increasing a braking force generated by a brake unit mounted on wheels in order to stop a vehicle when the vehicle starts moving during parking. is there.

[0002]

2. Description of the Related Art Conventionally, in vehicles such as automobiles, brake assist devices have been developed which can reduce the troublesome operation of a driver to brake. Such a conventional brake assist device is a device in which when a vehicle stops due to a brake operation, the computer detects the stop and holds the brake fluid pressure when the brake pedal is depressed even when the driver releases his / her foot from the brake pedal. This allows the driver to keep the vehicle stopped without continuing to depress the brake pedal.

A specific description of such an apparatus will be given below. For example, an actuator is provided on a hydraulic oil supply path of a brake of a vehicle so as to maintain a brake fluid pressure, and the vehicle stops when a brake pedal is depressed. When the brake pedal is released for a predetermined time and then released, the computer detects this and supplies air pressure or the like to the actuator to maintain the braking force.

[0004] This eliminates the need to continue depressing the brake pedal during traffic congestion or waiting for a traffic light, thereby reducing physical and mental fatigue. However,
In such a conventional brake assist device, the brake fluid pressure is kept constant during operation.For example, when the vehicle starts to move when the parking brake is weakly applied while parking on a slope or the like, the vehicle starts moving. Safety cannot be ensured by stopping the facility.

Therefore, recently, a parking brake safety device for automatically increasing the braking force generated by a brake unit mounted on wheels in order to stop the vehicle when the vehicle starts moving under its own weight on a slope or the like during parking has been developed. Is being developed. Specifically, the parking brake safety device includes a parking state determination unit that determines whether the vehicle is in a parking state, a wheel speed sensor that outputs a pulse signal corresponding to the rotation speed of the wheel, and a wheel. There has been proposed a configuration including a parking assist braking means for increasing a braking force generated by a brake unit, and activating the parking assist braking means in a procedure shown in FIG.

That is, first, it is determined whether or not the vehicle is parked by the parking state determining means (step 101). When it is determined that the vehicle is parked, the output of the wheel speed sensor is monitored.
When a pulse signal is output from the wheel speed sensor (step 102), it is determined that the vehicle has started to move during parking, and the parking assist braking means is immediately activated (step 10).
3).

[0007]

However, even when the vehicle is not moving, as shown in FIG. 3, it is affected by disturbance noise 104 such as radio interference and vibration around the parked vehicle.
In some cases, the wheel speed sensor outputs a pulse signal. Even in such a case, in the conventional method, the parking assist braking means is immediately activated just by outputting the pulse signal from the wheel speed sensor. In other words, the parking assist braking means is operated by the action of disturbance noise even though the vehicle is stopped, and as a result, excessive braking is performed on the brake unit and various members that supply the brake hydraulic pressure to the brake unit. And the life of the brake unit and various members for supplying the brake fluid pressure to the brake unit may be shortened.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and it is possible to prevent a malfunction of the parking assist braking means due to a pulse signal output from a wheel speed sensor due to the influence of disturbance noise. It is to provide a high parking brake safety device.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to stop a vehicle when the vehicle starts moving when parking.
A parking brake safety device for automatically increasing a braking force generated by a brake unit mounted on a wheel, a parking state determining means for determining whether the vehicle is in a parking state, and a pulse corresponding to a rotation speed of the wheel. A wheel speed sensor that outputs a signal, an acceleration determination unit that determines whether or not a moving acceleration of the vehicle calculated based on a change in each pulse signal output by the wheel speed sensor indicates a specified acceleration or less; A pulse signal determining unit that determines whether a predetermined number of pulses has been reached; and a parking assist braking unit that increases a braking force generated by a brake unit. The determination result of the parking state determining unit and an output of a wheel speed sensor are provided. Based on the above, when a pulse signal is output from the wheel speed sensor while the vehicle is parked, it is determined by the acceleration determination means that the vehicle is below the specified acceleration. This is achieved by a parking brake safety device that outputs only a loose signal to a pulse signal determination unit and, when the pulse signal determination unit determines that the specified number of pulses has been reached, activates a parking assist braking unit. .

Here, the moving distance of the vehicle can be calculated by integrating and counting (counting the number of pulses) the pulse signal detected and output by the wheel speed sensor in a normal state. Furthermore, the acceleration of the vehicle can be calculated for each pulse signal from each pulse signal based on the interval between the pulses or the time of one pulse. That is, first, the determination as to whether the pulse signal has reached the prescribed number of pulses means to determine whether or not the travel distance of the vehicle has reached the prescribed amount. This specified amount is used. Further, the determination as to whether or not the acceleration of the vehicle calculated for each pulse signal is equal to or less than the specified acceleration is used to determine whether or not the acceleration indicated by each pulse is not unduly large with respect to the preceding vehicle state. You. In other words, outputting only the pulse signal determined to indicate the specified acceleration or less to the pulse signal determination means 22 means that the pulse signal indicating the specified acceleration or more is not input to the pulse signal determination means 22. After excluding a certain pulse signal, the moving distance determination based on the number of pulses is performed.

Therefore, even if the wheel speed sensor outputs a pulse signal due to the influence of disturbance noise, if the number of pulses does not reach the specified number, it is determined that the vehicle is in a range in which the vehicle can be regarded as stopped.
It is possible to prevent the parking assist braking means from being erroneously operated, and to improve the operation reliability of the parking brake safety device. Further, in response to a case where the disturbance noise has a high-frequency component and the calculated acceleration value is unsuitable at the beginning of the movement of the vehicle, a pulse signal indicating a specified acceleration or more is excluded, and the parking assist braking means is removed. Can be prevented from being erroneously operated, and the operation reliability of the parking brake safety device can be enhanced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a parking brake safety device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a parking brake safety device according to the present invention. FIG. 1 is a block diagram showing a configuration of a parking brake safety device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation procedure of the parking brake safety device according to the embodiment shown in FIG.

As shown in FIG. 1, the parking brake safety device 1 according to the first embodiment detects a depression of a brake pedal 2 and outputs a brake fluid pressure corresponding to a depression force. Master cylinder 3 mounted on vehicle wheels
A brake unit 5 that operates with hydraulic pressure supplied from the
The braking force generated by the brake unit 5 can be increased or decreased by moving the hydraulic pressure supplied to the brake unit 5 from the master cylinder 3 to the brake unit 5 by moving the built-in piston forward or backward. Monitor the actuator 8, the motor 9 that drives the piston of the actuator 8 forward and backward, the wheel speed sensor 11 that outputs a pulse signal according to the rotation speed of the wheel, the brake operation by the driver, and the output of the wheel speed sensor 11. The control device 1 controls the operation of the motor 9 in accordance with the situation of the vehicle to automatically switch the brake unit 5 to a braking state or a non-braking state, or to increase or decrease the braking force generated by the brake unit 5
3 is provided.

The control unit 13 includes a parking state determination unit 21 for determining whether the vehicle is in a parking state and a wheel speed sensor 11.
Pulse signal determining means 22 for determining whether or not the pulse signal output from the vehicle has reached a predetermined number of pulses, and a moving acceleration of the vehicle calculated based on each pulse signal output from the wheel speed sensor 11 is equal to or less than a predetermined acceleration. This is provided with an acceleration determining means 26 for determining whether or not the braking force is generated and a parking assist braking means 23 for controlling the motor 9 of the actuator 8 so as to increase the braking force generated by the brake unit 5.

The parking state determining means 21 includes, for example, the setting of the key switch 14, the operation state of the clutch pedal 15, the operating state of the transmission 16, and the parking brake lever 1.
7 is monitored, for example, if the clutch pedal 15 is not operating, the transmission 16 is in the parking position or the idling position, and the parking brake lever 17 is operating, It is determined that the vehicle is parked.

The control device 13 operates the parking assist braking means 23 in the procedure shown in FIG. 2 so as to stop the vehicle when the vehicle starts moving due to insufficient braking force by the parking brake during parking. Here, the moving distance of the vehicle can be calculated by integrating and counting (counting the number of pulses) the pulse signal detected by the wheel speed sensor 11.
Further, the acceleration at the time of movement of the vehicle can be known from the differentiation of the movement speed calculated from each pulse signal.

First, when the parking state determination means 21 determines that the vehicle is in a parking state (step 201),
Monitoring of the output of the wheel speed sensor 11 is started (step 2).
02), when a pulse signal is output from the wheel speed sensor 11, the acceleration determining means 26 further determines whether or not the vehicle acceleration calculated for each pulse signal is equal to or less than a specified acceleration. The pulse signal determining means 22 determines only the pulse signal for which the calculated acceleration value is determined to be equal to or less than the specified acceleration
(Step 203). Then, the pulse signals transmitted by the pulse signal determination means 22 are integrated, and it is determined whether or not the number of pulses has reached the specified number, and it is determined whether or not the vehicle is in a permissible range for determining whether the vehicle is stationary or not (step 2)
04). Only when the pulse signal determining means 22 determines that the specified number of pulses has been reached, it is determined that the vehicle has actually started moving, and the parking assist braking means 23 is operated (step 205).

That is, outputting only the pulse signal determined to indicate that the calculated acceleration is equal to or lower than the specified acceleration to the pulse signal determining means 22 means that the pulse signal indicating the calculated acceleration is equal to or higher than the specified acceleration is input to the pulse signal determining means 22. That is, after the problematic pulse signal is excluded, it is determined whether the vehicle is in the allowable range of the vehicle stop state. Therefore, even if the wheel speed sensor 11 outputs a pulse signal under the influence of disturbance noise,
In a case where the disturbance noise has a high-frequency component and the calculated acceleration value is inappropriate at the beginning of the vehicle movement, it is possible to prevent the parking assist braking means from being operated erroneously. The operation reliability of the brake safety device can be improved.

The controller 13 releases the parking state when the clutch pedal 15 or the transmission 16 is newly operated from the parking state and the parking brake lever 17 is switched to the non-operating state. Judging that
The actuator 8 is caused to perform a pressure reducing operation via the parking assist braking means 23.

In the above embodiment, the control device 13
Has been designed to control the braking force of the brake unit 5 in order to prevent the vehicle from moving due to insufficient braking force of the parking brake during parking. However, the above control device 13 includes an anti-lock brake system and traction. A function for controlling the operation of the brake unit 5 may be provided as a control system or the like.

[0021]

According to the parking brake safety device of the present invention, it is determined whether or not the acceleration of the vehicle corresponding to each pulse signal is equal to or less than the specified acceleration. To determine whether or not a pulse signal indicating a predetermined acceleration or more is input to the pulse signal determination means 22, excluding a problematic pulse signal, and determining the allowable range of the vehicle stop state by integrating the number of pulses. It is determined whether or not there is. Therefore, even if the wheel speed sensor outputs a pulse signal due to the influence of disturbance noise, particularly, the case where the disturbance noise has a high-frequency component and the acceleration calculation value is unsuitable at the start of the movement of the vehicle, It is possible to prevent the parking assist braking means from being operated by mistake, and to further enhance the operation reliability of the parking brake safety device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a parking brake safety device according to the present invention.

FIG. 2 is a flowchart showing an operation procedure of the parking brake safety device of the embodiment shown in FIG.

FIG. 3 is a flowchart showing an operation procedure of the conventional parking brake safety device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parking brake safety device 3 Master cylinder 5 Brake unit 11 Wheel speed sensor 13 Control device 21 Parking state determination means 22 Pulse signal determination means 23 Parking auxiliary braking means 26 Acceleration determination means

Claims (1)

[Claims] 1. A brake unit (5) mounted on wheels for stopping a vehicle when the vehicle starts moving when parking.
A parking brake safety device for automatically increasing the braking force generated by the parking state determination means 21 for determining whether or not the vehicle is in a parking state.
And a wheel speed sensor 11 that outputs a pulse signal corresponding to the rotation speed of the wheel; and whether or not a vehicle acceleration calculated based on a change in each pulse signal output by the wheel speed sensor 11 indicates a specified acceleration or less. Acceleration determining means 26 for determining whether the pulse signal has reached a prescribed number of pulses, pulse signal determining means 22 for determining whether the pulse signal has reached a prescribed number of pulses, and parking assist braking means 2 for increasing the braking force generated by the brake unit 5
3 and the determination result of the parking state determination means 21 and the wheel speed sensor 11
When a pulse signal is output from the wheel speed sensor 11 while the vehicle is parked on the basis of the output of the vehicle, only the pulse signal determined to show the specified acceleration or less by the acceleration determination means 26 is determined by the pulse signal determination means 22. A parking brake safety device characterized in that when the pulse signal determining means 22 determines that the specified number of pulses has been reached, the parking assist braking means 23 is activated.