JP4004622B2 - Automatic brake device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an automatic brake device that monitors various information including a vehicle operation of a driver and automatically sets a brake device mounted on the vehicle to a braking state or a non-braking state depending on the state of the vehicle. Specifically, even if a failure occurs in the limit switch that controls the operation of the motor used as the drive source during the braking force release operation or the electrical system including the limit switch, the motor can be stopped properly. It relates to improvements to make it possible.
[0002]
[Prior art]
Recently, as a braking device for automobiles, various information related to vehicle operations such as a driver's braking operation and acceleration operation are monitored, and the braking device mounted on the vehicle is automatically braked according to the situation of the vehicle. Researches on automatic braking devices that can be in a state of being unbraking or not are active.
[0003]
These automatic brake devices were developed for the purpose of reducing the burden on the driver's braking operation and reducing the burden during driving, while at the same time realizing more reliable braking and improving safety. is there.
Until now, for such an automatic brake device, when the vehicle stops due to the driver's braking operation, the computer detects this, and even if the driver removes his foot from the brake pedal, the brake fluid pressure when the brake pedal is depressed is If the vehicle is about to move when the parking brake is loosened while parking (for example, Japanese Patent Application Laid-Open No. 3-121959) or the vehicle starts to move, the computer that detects it increases the brake fluid pressure to prevent the vehicle from starting to move. There has been proposed one (for example, JP-A-8-198094).
[0004]
Specifically, such an automatic brake device includes, for example, an actuator that is provided in a hydraulic pressure supply path of a brake device that operates by hydraulic pressure, and that adjusts the hydraulic pressure supplied to the brake device by a forward and backward movement of a piston, and an actuator A motor that drives the piston forward and backward, and a control device that automatically controls the operation of the motor according to vehicle conditions such as the presence or absence of a brake operation by the driver and automatically sets the brake device to a braking state or a non-braking state. It has been configured.
In such an automatic brake device, when the driver performs an operation that means release of braking, the motor drives the piston so that the actuator performs a pressure-reducing operation, thereby bringing the actuator into a non-braking state.
[0005]
By the way, in such an automatic brake device, when the piston is advanced or retracted to the limit position by the motor, if the motor is not stopped promptly, an excessive current flows through a device such as a motor or a relay for controlling the operation of the motor. These devices such as motors and relays may be damaged due to excessive current, or mechanical parts may be damaged due to excessive stress acting on the advancing / retreating force applied from the motor to the piston.
Therefore, conventionally, for example, when applied to the above-described parking brake safety device and the braking state is ensured and the decompression operation is completed, when the motor retreats to the reference position, the limit switch detects that and the limit switch detects it. A device (for example, Japanese Patent Application Laid-Open No. 8-296676) has been developed that controls the stop of a motor based on a switch signal.
[0006]
[Problems to be solved by the invention]
However, even if the motor is turned on / off by the limit switch as described above, if the limit switch fails for some reason, the motor will not stop properly and the motor, relay, or other equipment will be damaged by excessive current. Or, there is a possibility that inconveniences such as breakage of mechanical parts such as pistons due to excessive stress acting due to continued operation of the motor may occur.
[0007]
The present invention has been made in view of the above circumstances, and can properly stop a motor even when a failure occurs in a limit switch that controls the operation of a motor that is used as a drive source during a braking force releasing operation. An object of the present invention is to provide an automatic brake device that does not cause inconvenience due to non-stop of the motor.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an automatic brake device according to the present invention is provided with an actuator that is provided in a hydraulic pressure supply path of a brake device that operates by hydraulic pressure, and that adjusts the hydraulic pressure supplied to the brake device by a forward and backward movement of a piston. A motor for driving the piston of the actuator to move forward and backward, a detecting means for detecting when the piston is retracted to a reference position during the pressure-reducing operation of the actuator by the motor, and controlling the operation of the motor according to the situation of the vehicle And a control device that automatically puts the brake device into a braking state or a non-braking state, and the control device includes a motor stop circuit that stops the motor based on a detection signal of the detection means, and the motor. A timer is used to stop the motor after a predetermined time has elapsed since the timing of the piston started. Characterized in that it was equipped with a door.
[0009]
And according to the said structure, if the limit switch used as a detection means is operating normally, at the time of pressure reduction operation of the actuator, when the piston retracts to the reference position, the motor is stopped by the operation of the motor stop circuit.
Even if the limit switch or the electric system including the limit switch fails due to some cause and the motor stop circuit does not operate, the motor is stopped by the operation of the timer circuit after a predetermined time has elapsed.
In other words, the motor stop operation during the decompression operation of the actuator is doubly safe by the motor stop circuit and the timer circuit, and even if the limit switch fails, the motor can be stopped properly and reliably. Thus, there is no inconvenience caused by the motor not stopping, and the safety and reliability of the automatic brake device can be improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an automatic brake device according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of an automatic brake device according to the present invention, and FIG. 2 is a flowchart of a motor control operation during a pressure reducing operation in the automatic brake device of FIG.
[0011]
The automatic brake device 1 according to this embodiment detects a depression state of the brake pedal 2 and outputs a brake fluid pressure corresponding to the depression force, and is provided on a vehicle wheel and supplied from the master cylinder 3. The hydraulic brake device 5 that operates with the hydraulic pressure that is applied, and the actuator that is provided in the hydraulic pressure supply path 6 from the master cylinder 3 to the brake device 5 and that adjusts the supplied hydraulic pressure to the brake device 5 by the forward and backward movement of the built-in piston 8, a motor 9 that drives the piston forward and backward, a limit switch 22 that detects when the piston is retracted to the reference position by the motor 9 during the pressure-reducing operation of the actuator 8, a brake operation by the driver, etc. The control device which controls the operation of the motor 9 according to the situation and automatically sets the brake device 5 to the braking state or the non-braking state. It is configured to include a 3 and.
[0012]
The automatic brake device 1 shown in this embodiment is applied to the brake device 5 by the actuator 8 in order to prevent the vehicle from moving due to insufficient braking force by the parking brake when the driver leaves the vehicle with the parking brake applied. The supplied brake fluid pressure is controlled.
[0013]
Specifically, the control device 13 is based on the depression of the clutch pedal 15, the operating state of the transmission 16, the operating state of the parking brake lever 17, the rotational speed of the wheel by the speed sensor 18, and the piston of the actuator 8 described above. As detection means for detecting the exit to the position, for example, various information indicating the vehicle status, such as an output signal of the limit switch 22, is monitored, and the vehicle status is determined based on the monitoring information.
For example, if the clutch pedal 15 is inactive, the transmission 16 is in the parking position or the accelerator pedal is in the non-depressed position and the parking brake lever 17 is in operation, it is determined that the vehicle is parked. During parking, it is determined from the output signal of the speed sensor 18 whether the vehicle is in a stopped state or starts moving. When the vehicle starts moving, the brake fluid pressure is increased by the actuator 8 to stop the vehicle. Further, 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, the control device 13 determines that the parking state has been released. Then, the actuator 8 is depressurized to release the brake.
[0014]
Further, the control device 13 is used for controlling the operation of the motor 9 during the pressure-reducing operation of the actuator 8, and a motor stop circuit 20 that stops the motor 9 based on the detection signal of the limit switch 22, and starts the withdrawal operation of the piston by the motor 9. And a timer circuit 21 for stopping the motor 9 after a lapse of a predetermined time, and controlling on / off of the motor 9 as shown in FIG.
[0015]
That is, when the controller 13 causes the actuator 8 to perform a pressure reducing operation, first, as described above, is the pressure reduction start condition established from the operating state of the clutch pedal 15, the transmission 16, the parking brake lever 17, or the like? If the depressurization start condition is satisfied, the driving of the motor 9 is started so that the actuator 8 performs the depressurization operation (step 102).
Simultaneously with the start of the withdrawal operation of the piston of the actuator 8 by the motor 9, the motor stop circuit 20 and the timer circuit 21 start to operate, and the timer circuit 21 starts measuring time (step 103).
[0016]
Then, it is determined whether or not the limit switch 22 or an electric system including the limit switch 22 is normal (step 105). If the limit switch 22 is normal, a predetermined signal is sent from the limit switch 22 to the motor stop circuit 20 when the piston retracts to the reference position. And the motor stop circuit 20 is operated to stop the motor 9 (step 106).
On the other hand, if it is determined in step 105 that the limit switch 22 has failed for some reason (or the signal line from the limit switch 22 to the control device 13 is broken or short-circuited or the input circuit of the limit switch 22 has failed). The motor 9 is stopped by the output of the timer circuit 21 after a predetermined time has elapsed. The timer circuit 21 described above is a time obtained by adding a slight delay time to the standard time required from the start of the piston withdrawal operation to the reference position when the piston withdrawal operation by the motor 9 is performed normally. Is set as the required time.
[0017]
That is, the stop operation of the motor 9 during the decompression operation of the actuator 8 is double safe by the motor stop circuit 20 and the timer circuit 21. In the steady state, the operation of the motor stop circuit 20 by the limit switch 22 is performed. Priority is given to the timer circuit 21 in place of the limit switch 22 in an abnormal state. As a result, even if a failure occurs in the limit switch 22 or an electric system including the limit switch 22, the motor 9 can be stopped properly and reliably, and there is an inconvenience such as an overload of supply current due to the non-stop of the motor 9. Generation | occurrence | production can be prevented and the safety | security and reliability in the automatic brake device 1 can be aimed at.
[0018]
In the above-described embodiment, the automatic brake device 1 automatically applies the braking force to prevent the vehicle from starting due to insufficient braking force due to the parking brake when the driver leaves the vehicle with the parking brake applied. The present invention functions as a so-called parking brake safety device, but when the vehicle is stopped by stepping on the brake pedal, the present invention can be used from the brake pedal until a re-start or acceleration operation is performed. The present invention is also applicable to an automatic brake device that maintains the braking force during the previous braking operation even when the foot is released.
[0019]
Further, the control device 13 targets the clutch pedal 15, the transmission 16, or the parking brake lever 17 as shown in the above embodiment for monitoring contents for detecting the vehicle situation and the driver's operation. Needless to say, the present invention is not limited and the design can be changed as appropriate without departing from the spirit of the present invention.
[0020]
【The invention's effect】
According to the automatic brake device of the present invention, if the limit switch or the like is operating normally, the motor is stopped by the operation of the motor stop circuit when the piston is retracted to the reference position during the pressure reducing operation of the actuator.
If the limit switch or the like is broken for some reason and the motor stop circuit does not operate, the motor is stopped by the operation of the timer circuit after a predetermined time has elapsed.
In other words, the motor stop operation during the decompression operation of the actuator is doubly safe by the motor stop circuit and the timer circuit, and even if a limit switch or the like fails, the motor is stopped properly and reliably. Therefore, it is possible to eliminate the inconvenience caused by the non-stop of the motor and improve the safety and reliability of the automatic brake device.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of an automatic brake device according to the present invention.
FIG. 2 is a flowchart at the time of pressure reduction operation of the automatic brake device of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Automatic brake device 2 Brake pedal 3 Master cylinder 5 Hydraulic brake device 6 Hydraulic pressure supply path 8 Actuator 9 Motor 13 Control device 15 Clutch pedal 16 Transmission 17 Parking brake lever 18 Speed sensor 20 Motor stop circuit 21 Timer circuit 22 Limit switch ( Detection means)

Claims (1)

An actuator that is provided in a hydraulic pressure supply path of a brake device that operates by hydraulic pressure, and that adjusts the hydraulic pressure supplied to the brake device by an advance / retreat operation of a piston; a motor that drives the piston of the actuator to advance / retract; and Detection means for detecting when the piston is retracted to a reference position during the pressure-reducing operation of the actuator, and controlling the operation of the motor according to the situation of the vehicle to automatically put the brake device into a braking state or a non-braking state And a control device that
The control device includes a motor stop circuit for stopping the motor based on a detection signal of the detection means, and a timer for starting the time measurement in accordance with the start of the withdrawal operation of the piston by the motor and stopping the motor after a predetermined time has elapsed. An automatic brake device characterized by being equipped with a circuit.

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