Brake control method and brake device

Abstract

Provided is a brake control method for a brake device for operating, on the basis of an electric signal outputted by a sensor (11a) for detecting an operation amount of a brake pedal (10), an actuator (15a) that drives a brake mechanism that applies friction braking force to a vehicle, the method involving: determining whether or not the brake pedal is pressed on the basis of the output signal of a sensor, and determining whether or not an ignition switch is switched off while the brake pedal is being pressed (S3); and when the ignition switch is switched off while the brake pedal is being pressed, the actuator is continuously operated on the basis of the output signal of the sensor even after the ignition switch is switched off (S5).

Description

Brake Control Method and Brake Device

[0001] The present invention relates to a brake control method and a brake device.

[0002] The vehicle power supply system described in Patent Document 1 below restricts the power supply to devices in the vehicle device group that do not require power supply based on the determination result of the running state of the vehicle.

[0003] Japanese Patent Application Laid-Open No. 2013-116694

[0004] In an electric brake device that operates an actuator that drives a braking mechanism of a vehicle based on an electric signal output by a sensor that detects the operation amount of a brake pedal, when the operation of the actuator is stopped when the ignition switch is switched off, it becomes impossible to generate braking force by the brake pedal after the ignition switch is switched off. The present invention aims to enable control of the braking force by the brake pedal after the ignition switch is switched off according to the driver's intention in a brake device that operates an actuator that drives a braking mechanism of a vehicle based on an electric signal output by a sensor that detects the operation amount of the brake pedal.

[0005] According to one aspect of the present invention, there is provided a brake control method for a brake device that operates an actuator that drives a braking mechanism that applies frictional braking force to a vehicle based on an electric signal output by a sensor that detects the operation amount of a brake pedal. In the brake control method, it is determined whether the brake pedal is depressed based on the output signal of the sensor, it is determined whether the ignition switch is switched off while the brake pedal is depressed, and when the ignition switch is switched off while the brake pedal is depressed, the operation of the actuator based on the output signal of the sensor is continued even after the ignition switch is switched off.

[0006] According to the present invention, in a braking system that operates an actuator driving the braking mechanism of a vehicle based on an electrical signal output by a sensor that detects the amount of brake pedal operation, it becomes possible to control the braking force applied by the brake pedal after the ignition switch has been turned off, according to the driver's intention. The objectives and advantages of the present invention are embodied and achieved using the elements and combinations thereof set forth in the claims. Both the above general description and the following detailed description are merely illustrative and explanatory and should be understood not to limit the present invention in any way that would imply the claims.

[0007] This figure shows a schematic configuration example of the brake system of the embodiment. (a) to (d) are time charts of a first example of the operation of the brake system of the embodiment. (a) to (d) are time charts of a first example of the operation of the brake system of the embodiment. This is a flowchart of the brake control method of the embodiment.

[0008] (Configuration) Figure 1 is a diagram showing a schematic configuration example of the brake system 3 of the embodiment. The brake system 3 includes a braking mechanism that applies frictional braking force to the right front wheel 2FR, left front wheel 2FL, right rear wheel 2RR, and left rear wheel 2RL of the vehicle 1. The brake system 3 is an example of the "brake device" described in the claims. In the following description, the right front wheel 2FR, left front wheel 2FL, right rear wheel 2RR, and left rear wheel 2RL may be collectively referred to as "wheel 2". Also, in Figure 1, thin solid lines indicate electrical signal lines, thick solid lines indicate hydraulic piping, and dashed lines indicate power lines that supply power from the vehicle power source (e.g., onboard battery).

[0009] The brake system 3 includes a brake pedal 10, a brake operation detection circuit 11, a first controller 12, a second controller 13, pumps 14 and 15, brake calipers 16FR, 16FL, 16RR and 16RL, electric parking brakes 17R and 17L, a reservoir tank 18, and hydraulic piping 19 and 20. In the following description, brake calipers 16FR, 16FL, 16RR and 16RL will be collectively referred to as "brake caliper 16," and electric parking brakes 17R and 17L will be collectively referred to as "electric parking brake 17." Brake caliper 16, reservoir tank 18, and hydraulic piping 19 and 20 are examples of the "braking mechanism" described in the claims.

[0010] The brake system 3 is a so-called brake-by-wire brake system that electrically detects the amount of operation of the brake pedal 10 using a sensor 11a, and operates a motor 14a, which is an actuator that drives a braking mechanism that applies frictional braking force to the vehicle, based on the electrical signal output by the sensor 11a. The brake-by-wire brake system 3 is a brake system that does not have a mechanical link (for example, a mechanical backup mechanism) between the actuator or power booster that drives the braking mechanism and the brake pedal 10.

[0011] The brake pedal 10 is a pedal used by the driver to input brake operation. The brake operation detection circuit 11 includes a sensor 11a and a control circuit 11b. The sensor 11a detects the stroke amount (amount of depression) and the force applied when the driver depresses the brake pedal 10, and outputs an electrical detection signal corresponding to the detected stroke amount and force applied.

[0012] The control circuit 11b generates a brake operation detection signal Sb, which is a digital signal indicating the stroke amount and pedal force of the brake pedal 10, by converting the detection signal from the sensor 11a from analog to digital, and outputs the generated brake operation detection signal Sb to the first controller 12 and the second controller 13.

[0013] The first controller 12 is an electronic control unit (ECU) that operates the brake calipers 16 of each wheel 2 to generate frictional braking force by driving the motor 14a of the pump 14 based on the brake operation detection signal Sb received from the sensor 11a. The first controller 12 comprises a control circuit 12a and a driver circuit 12b.

[0014] The control circuit 12a calculates a target value for the hydraulic pressure of the working fluid (brake fluid) supplied to the wheel cylinder of the brake caliper 16 according to the stroke amount and pedal force of the brake pedal 10, and outputs a control amount for the pump 14 that achieves the calculated target value to the driver circuit 12b. The driver circuit 12b operates the brake caliper 16 by driving the motor 14a of the pump 14 based on the control signal from the control circuit 12a.

[0015] For example, the control circuit 12a may include a processor such as a CPU (Central Processing Unit) or MPU (Micro-Processing Unit), and a memory device including a semiconductor memory device, a magnetic memory device, an optical memory device, etc. The operation of the control circuit 12a described below may be realized by the processor executing a computer program stored in the memory device. The same applies to the control circuit 13a described later. Also, for example, the driver circuit 12b may include a switching element that controls the drive current that drives the motor 14a based on a control signal from the control circuit 12a. The same applies to the driver circuit 13b described later.

[0016] The second controller 13 is an electronic control unit that controls the electric parking brake 17 and, in the event of a malfunction in the first controller 12 or pump 14, activates the brake caliper 16 based on the brake operation detection signal Sb received from the sensor 11a to generate frictional braking force, on behalf of the first controller 12. The second controller 13 comprises a control circuit 13a and a driver circuit 13b.

[0017] The control circuit 13a activates the electric parking brakes 17R and 17L in response to the operation of a parking switch (not shown) or the operation of setting the shift lever to the "P (parking)" position, thereby generating braking force on the right rear wheel 2RR and the left rear wheel 2RL, respectively. In the following description, the driver's operation to activate the electric parking brake 17 (operating the parking switch or setting the shift lever to the "P" position) may be referred to as "electric parking brake operation".

[0018] For example, the electric parking brake 17 may include an actuator (e.g., an electric motor) (not shown), and a brake shoe and brake drum that are pressed against by the actuator. When the control circuit 13a receives an electric parking brake operation, it outputs a control signal to the driver circuit 13b instructing the operation of the electric parking brake 17. The driver circuit 13b operates the electric parking brake 17 based on the control signal from the control circuit 13a. That is, the driver circuit 13b drives the actuator of the electric parking brake 17 to press the brake shoe against the brake drum, thereby generating braking force on the rear wheels 2RR and 2RL.

[0019] Furthermore, if an abnormality occurs in the first controller 12 or the pump 14, the control circuit 13a calculates a target value for the hydraulic pressure of the working fluid supplied to the wheel cylinder of the brake caliper 16 according to the stroke amount and pedal force of the brake pedal 10, and outputs the control amount of the pump 15 that achieves the calculated target value to the driver circuit 13b. The driver circuit 13b operates the brake caliper 16 by driving the motor 15a of the pump 15 based on the control signal from the control circuit 13a.

[0020] The braking mechanism shown in Figure 1 is illustrative, and the present invention is not intended to limit the braking mechanisms to which it applies. For example, the second controller 13 may be omitted, and the first controller 12 may control the electric parking brake 17.

[0021] Pumps 14 and 15 are hydraulic devices driven by built-in motors 14a and 15b, respectively, which pressurize the working fluid that operates the brake caliper 16. Pumps 14 and 15 supply the working fluid to the wheel cylinder of the brake caliper 16 via hydraulic piping 19. The working fluid supplied to the wheel cylinder is recovered via hydraulic piping 19.

[0022] Pumps 14 and 15 are also connected to a reservoir tank 18 via hydraulic piping 20. The reservoir tank 18 is a container for holding working fluid, and working fluid is supplied from the reservoir tank 18 to pumps 14 and 15 as needed. The reservoir tank 18 also receives and stores excess working fluid that flows out from pumps 14 and 15. Note that pumps 14 and hydraulic piping 19 and 20 may be provided separately for each brake caliper 16FR, 16FL, 16RR, and 16RL. The same applies to pump 15.

[0023] Next, an example of the operation of the brake system 3 of the embodiment will be described. When the ignition (IGN) switch 5 of the vehicle 1 is ON, the brake operation detection circuit 11, the first controller 12, the second controller 13, and the pumps 14 and 15 are operated by power supplied from the vehicle power supply 4. On the other hand, when the vehicle 1 is stationary and the ignition switch 5 is OFF, the brake operation detection circuit 11, the first controller 12, the second controller 13, and the pumps 14 and 15 are shut down, thereby suppressing the power consumption of the vehicle power supply 4.

[0024] If the ignition switch 5 of vehicle 1 is switched off and the brake system 3 is immediately shut down, then as soon as the ignition switch 5 is switched off, the driver will be unable to operate the brake pedal and generate braking force. For this reason, after the ignition switch 5 is switched off, the driver will be unable to operate the brake pedal 10 and apply frictional braking force to vehicle 1 in situations where vehicle 1 is moving (for example, when vehicle 1 is stopped on a slope, when the weight of vehicle 1 changes, or when vehicle 1 is being towed).

[0025] Therefore, in the brake system 3 of this embodiment, it is determined whether the brake pedal 10 is depressed or not based on the output signal of the sensor 11a, and it is determined whether the ignition switch 5 has been switched off while the brake pedal 10 is depressed. If the ignition switch 5 has been switched off while the brake pedal 10 is depressed, the brake system 3 is not shut down even after the ignition switch 5 has been switched off, and the operation of operating the motor 14a of the pump 14 based on the output signal of the sensor 11a is continued.

[0026] This prevents the brake operation detection circuit 11, the first controller 12, and the motor 14a of the pump 14 from shutting down if the brake pedal 10 is pressed when the ignition switch 5 is switched off. Therefore, according to the driver's wishes, even after the ignition switch 5 is switched off, the driver can operate the brake pedal 10 to apply frictional braking force to the vehicle 1.

[0027] Next, an example of the function and operation of each part of the brake system 3 will be described. The control circuit 12a of the first controller 12 receives an ignition signal indicating the on / off state of the ignition switch 5 and determines whether or not the ignition switch 5 has switched from on to off.

[0028] Furthermore, the control circuit 12a determines whether the brake pedal 10 is depressed or not based on the brake operation detection signal Sb output from the sensor 11a, and determines whether the ignition switch 5 was switched off while the brake pedal 10 was depressed or not.

[0029] If the control circuit 12a determines that the ignition switch 5 has been switched off while the brake pedal 10 is depressed, it starts counting the shutdown timer, which is the remaining time until the brake system 3 is shut down.

[0030] In this specification, shutting down the brake system 3 means stopping the operation of the control circuit 11b of the brake operation detection circuit 11 and the control circuit 13a of the second controller 13, which is connected to the control circuit 12a of the first controller 12, thereby stopping the drive control of the driver circuit 12b and motor 14a by the control circuit 12a and the drive control of the driver circuit 13b and motor 15a by the control circuit 13a. In other words, shutting down the brake system 3 includes stopping the power supply to the driver circuits 12b and 13b and to the motors 14a and 15a.

[0031] When the shutdown timer starts counting, the control circuit 12a continues to monitor the depressed state of the brake pedal 10 based on the brake operation detection signal Sb received from the sensor 11a, and continues to count the shutdown timer if the brake pedal 10 is continuously depressed, thereby measuring the duration for which the brake pedal 10 is continuously depressed. The control circuit 12a suspends the start of the shutdown of the brake system 3 until the value of the shutdown timer (i.e., the duration) reaches a predetermined value Th.

[0032] When the value of the shutdown timer reaches a predetermined value Th, the control circuit 12a outputs a parking brake operation command to the control circuit 13a of the second controller 13, instructing the operation of the electric parking brake. Upon receiving the parking brake operation command, the control circuit 13a outputs a control signal to the driver circuit 13b, instructing the operation of the electric parking brake 17. The driver circuit 13b operates the electric parking brake 17 based on the control signal from the control circuit 13a. For example, the predetermined value Th may be set to a time (e.g., 2 to 3 minutes) during which the driver can be considered to have the intention to park the vehicle 1.

[0033] When the brake shoe of the electric parking brake 17 is pressed against the brake drum and the actuator operation is completed, the electric parking brake 17 transitions from a non-operated state to an operated state, and the operation process of the electric parking brake 17 is completed. Once the operation process of the electric parking brake 17 is completed, the control circuit 13a notifies the control circuit 12a that the operation process of the electric parking brake 17 has been completed.

[0034] When the control circuit 13a receives a notification that the operation process of the electric parking brake 17 has been completed, the control circuit 12a shuts down the brake system 3. As a result, the control circuit 12a measures the duration for which the brake pedal 10 is continuously pressed down during the period after the ignition switch 5 is turned off, and maintains drive control of the motor 14a based on the brake operation detection signal Sb until the duration reaches a predetermined value Th.

[0035] Furthermore, before the value of the shutdown timer reaches a predetermined value Th, if the control circuit 13a receives an electric parking brake operation from the driver while the control circuit 12a is timing the shutdown timer (while the start of the shutdown of the brake system 3 is being held in abeyance), it outputs a control signal to the driver circuit 13b instructing the operation of the electric parking brake 17.

[0036] When the operation process of the electric parking brake 17 is completed, the control circuit 13a notifies the control circuit 12a that the operation process of the electric parking brake 17 has been completed. Upon receiving the notification from the control circuit 13a that the operation process of the electric parking brake 17 has been completed, the control circuit 12a shuts down the brake system 3.

[0037] After the brake system 3 has shut down, when the driver switches the ignition switch 5 to the ON position, the control circuit 12a is activated by the input of an ignition signal indicating that the ignition switch 5 is ON. The control circuit 12a, activated by the ignition signal, then activates the driver circuit 12b and control circuits 11b and 13a, and control circuit 13a activates the driver circuit 13b, thereby returning the brake system 3 to its normal operating state.

[0038] Furthermore, while the shutdown timer is being set (while the start of the shutdown of the brake system 3 is being held in abeyance), if the driver releases the brake pedal 10 once (momentarily) and then presses it back down, or presses the brake pedal 10 further from its current position, causing a change in the stroke amount (operation amount) of the brake pedal 10, the control circuit 12a may reset the value of the shutdown timer to "0" and restart the timing of the continuous pressing period of the brake pedal 10 from "0".

[0039] This allows the shutdown of the brake system 3 to be delayed, prioritizing the driver's intentions. For example, when the vehicle 1 is stopped on a slope and the ignition switch 5 is turned off, the brake system 3 can be kept running to prevent the vehicle 1 from rolling down the slope due to its own weight, or to allow the vehicle 1 to stop even if it rolls down the slope due to its own weight.

[0040] Furthermore, an upper limit may be set for the number of times the shutdown timer value is reset to "0" when the stroke amount (operated amount) of the brake pedal 10 changes. In other words, after the number of times the shutdown timer value is reset to "0" exceeds the upper limit, the shutdown timer may be prohibited from being reset even if the stroke amount (operated amount) changes.

[0041] As a result, even though the brake pedal 10 is continuously depressed with a constant stroke amount, it is possible to prevent the value of the shutdown timer from being reset to "0" due to vibrations of the vehicle 1 or noise in the brake operation detection signal Sb, thereby making it impossible to continuously shut down the brake system 3. In addition to or instead of this, the control circuit 12a may prohibit resetting of the shutdown timer after a predetermined time has elapsed since the ignition switch 5 was switched off.

[0042] While the control circuit 12a is timing the shutdown timer (while holding off on starting the shutdown of the brake system 3), if the depression of the brake pedal 10 is stopped (if the operation amount of the brake pedal 10 becomes 0), the control circuit 12a may assume that the driver intends to park the vehicle 1 when the duration of the state in which the brake pedal 10 is not depressed reaches a predetermined value Th.

[0043] In this case, the control circuit 12a may output a control signal instructing the operation of the electric parking brake 17 to the driver circuit 13b. When receiving a notification from the control circuit 13a indicating that the operation process of the electric parking brake 17 has been completed, the control circuit 12a may shut down the brake system 3.

[0044] (Operation) FIGS. 2(a) to 2(d) are time charts of a first example of the operation of the brake system 3 of the embodiment, and FIGS. 2(a), 2(b), 2(c), and 2(d) respectively show the stroke amount (operation amount) of the brake pedal 10, the state of the ignition switch 5, the state of the brake system 3, and the state of the electric parking brake. The same applies to FIGS. 3(a) to 3(d).

[0045] At time t0, when the ignition switch 5 is switched from on to off while the brake pedal 10 is depressed (the operation amount of the brake pedal 10 is B1 which is greater than 0), the control circuit 12a of the first controller 12 starts timing the shutdown timer and holds off on starting the shutdown of the brake system 3. As a result, the operation of the brake system 3 continues even after time t0.

[0046] While the operation amount of the brake pedal 10 is maintained at a constant value during the timing of the shutdown timer by the control circuit 12a, when the elapsed time from the time point t0 reaches a predetermined value Th at the time point t1, the value of the shutdown timer reaches the predetermined value Th. The control circuit 12a outputs a parking brake operation command to the control circuit 13a of the second controller 13, and the control circuit 13a operates the electric parking brake 17.

[0047] At a subsequent time point t2, when the control circuit 13a confirms the completion of the operation process of the electric parking brake 17, the control circuit 13a notifies the control circuit 12a that the operation process of the electric parking brake 17 has been completed. The control circuit 12a shuts down the brake system 3. At a subsequent time point t3, when the driver stops depressing the brake pedal 10, the operation amount of the brake pedal 10 becomes 0.

[0048] FIGS. 3(a) to 3(d) are time charts of the first example of the operation of the brake system 3 of the embodiment. At the time point t0, when the ignition switch 5 is switched from on to off with the brake pedal 10 depressed, the control circuit 12a of the first controller 12 starts the timing of the shutdown timer and holds off the start of the shutdown of the brake system 3.

[0049] Thereafter, when the brake operation amount changes before the elapsed time from the time point t0 reaches the predetermined value Th, the control circuit 12a resets the value of the shutdown timer to "0". The control circuit 12a restarts the timing of the shutdown timer from the time point t10 when the change in the brake operation amount stops and becomes constant at the value B2. When the value of the shutdown timer reaches the predetermined value Th at the time point t11 when the elapsed time from the time point t10 reaches the predetermined value Th, the control circuit 12a outputs a parking brake operation command to the control circuit 13a of the second controller 13, and the control circuit 13a operates the electric parking brake 17.

[0050] At a subsequent time t12, when the control circuit 13a confirms the completion of the operation process of the electric parking brake 17, the control circuit 13a notifies the control circuit 12a that the operation process of the electric parking brake 17 has been completed. The control circuit 12a shuts down the brake system 3. At a subsequent time t13, when the driver stops pressing the brake pedal 10, the amount of operation of the brake pedal 10 becomes 0.

[0051] Figure 4 is a flowchart of the brake control method according to the embodiment. In step S1, the control circuit 12a of the first controller 12 determines whether the ignition switch 5 has switched from on to off. If the ignition switch 5 has not switched off (step S1:N), the process returns to step S1. If the ignition switch 5 has switched off (step S1:Y), the process proceeds to step S2.

[0052] In step S2, the sensor 11a of the brake operation detection circuit 11 detects the amount of operation (stroke) of the brake pedal 10. In step S3, the control circuit 12a determines whether the brake pedal 10 is depressed or not based on the amount of operation detected in step S2. If the brake pedal 10 is not depressed (step S3: N), the process proceeds to step S11. If the brake pedal 10 is depressed (step S3: Y), the process proceeds to step S4.

[0053] In step S4, the control circuit 12a starts timing the shutdown timer. In step S5, the control circuit 12a determines whether the value of the shutdown timer exceeds a predetermined value Th. If the value of the shutdown timer exceeds the predetermined value Th (step S5: Y), the process proceeds to step S10. If the value of the shutdown timer does not exceed the predetermined value Th (step S5: N), the process proceeds to step S6.

[0054] In step S6, the control circuit 13a of the second controller 13 determines whether or not it has received an electric parking brake operation from the driver. If the electric parking brake operation is received (step S6: Y), the process proceeds to step S10. If the electric parking brake operation is not received (step S6: N), the process proceeds to step S7.

[0055] In step S7, the sensor 11a detects the amount of operation (stroke) of the brake pedal 10. In step S8, the control circuit 12a determines, based on the amount of operation detected in step S7, whether the amount of operation of the brake pedal 10 has changed due to pressing down or releasing the brake pedal 10. If the amount of operation of the brake pedal 10 does not change (step S8: N), the process returns to step S5. If the amount of operation of the brake pedal 10 has changed (step S8: Y), the process proceeds to step S9.

[0056] In step S9, the control circuit 12a resets the shutdown timer value to "0". The process then returns to step S5. In step S10, the control circuit 13a activates the electric parking brake 17. In step S11, once the activation process of the electric parking brake 17 is complete, the control circuit 12a shuts down the brake system 3.

[0057] (Effects of the Embodiment) (1) In a brake control method for a brake device that operates an actuator that drives a braking mechanism that applies frictional braking force to a vehicle based on an electrical signal output by a sensor that detects the amount of operation of the brake pedal, it is determined whether or not the brake pedal is depressed based on the output signal of the sensor, and it is determined whether or not the ignition switch has been switched off while the brake pedal is depressed. If the ignition switch has been switched off while the brake pedal is depressed, the actuator continues to be operated based on the output signal of the sensor even after the ignition switch has been switched off.

[0058] This allows the actuator that drives the braking mechanism to continue operating if the brake pedal is pressed when the ignition switch is turned off. Therefore, the driver can operate the brake pedal to apply frictional braking force to the vehicle even after the ignition switch has been turned off, according to the driver's wishes.

[0059] (2) After the ignition switch is turned off, the parking brake may be activated and then the actuator may be stopped after the brake pedal has been continuously pressed for a predetermined time. This allows the parking brake to be activated to ensure the vehicle is stopped and then the actuator that drives the braking mechanism to be stopped when the brake pedal has been continuously pressed for a predetermined time and the driver's intention to park can be estimated. As a result, power consumption caused by continuously operating the actuator to stop the vehicle 1 can be suppressed.

[0060] (3) The duration for which the brake pedal is depressed during the period after the ignition switch is turned off is measured by a timer, and if the amount of brake pedal operation detected by the sensor changes after the start of measuring the duration, the duration may be reset to 0, and the actuator may be operated based on the output signal of the sensor until the duration reaches a predetermined time.

[0061] This allows the stopping of the actuator that drives the braking mechanism to be delayed, prioritizing the driver's intentions. For example, when the vehicle is stopped on a slope and the ignition switch 5 is turned off, the actuator can be kept running to prevent the vehicle from rolling down the slope due to its own weight, or to allow the vehicle to stop even if it rolls down the slope due to its own weight.

[0062] (4) After the number of times the duration has been reset to 0 exceeds the upper limit, the reset of the duration may be prohibited even if the amount of brake pedal operation detected by the sensor changes. This prevents the shutdown timer value from being reset to "0" and the brake system 3 from being shut down further due to vehicle vibration or noise in the brake operation amount detection signal, even though the brake pedal is being pressed down by a constant amount.

[0063] All examples and conditional terms set forth herein are intended for educational purposes to help the reader understand the concepts given by the inventors for the advancement of the invention and the art, and should be interpreted without limitation to the examples and conditions specifically described herein, as well as the configuration of examples relating to demonstrating the superiority and inferiority of the invention. Although embodiments of the invention are described in detail, it should be understood that various changes, substitutions, and modifications are possible without departing from the spirit and scope of the invention.

[0064] 1...Vehicle, 2FL...Left front wheel, 2FR...Right front wheel, 2RL...Rear wheel, 2RL...Left rear wheel, 3...Brake system, 4...Vehicle power supply, 5...Ignition switch, 10...Brake pedal, 11...Brake operation detection circuit, 11a...Sensor, 11b, 12a, 13a...Control circuit, 12...First controller, 12b, 13b...Driver circuit, 14...Pump, 14a...Motor, 15...Pump, 15a, 15b...Motor, 16FL, 16FR, 16RL, 16RR...Brake caliper, 17L, 17R...Electric parking brake, 18...Reservoir tank, 19, 20...Hydraulic piping

Claims

1. A brake control method for a brake system that operates an actuator that drives a braking mechanism that applies frictional braking force to a vehicle based on an electrical signal output by a sensor that detects the amount of operation of the brake pedal, characterized in that: it is determined whether or not the brake pedal is depressed based on the output signal of the sensor; it is determined whether or not the ignition switch has been switched off while the brake pedal is depressed; and if the ignition switch has been switched off while the brake pedal is depressed, the actuator continues to be operated based on the output signal of the sensor even after the ignition switch has been switched off.

2. The brake control method according to claim 1, characterized in that, after the ignition switch is turned off, the parking brake is activated and then the operation of the actuator is stopped after a predetermined time has been reached while the brake pedal has been continuously pressed.

3. The brake control method according to claim 2, characterized in that a timer measures the duration for which the brake pedal is depressed during the period after the ignition switch is turned off, and if the amount of operation of the brake pedal detected by the sensor changes after the start of measuring the duration, the duration is reset to 0, and the actuator is continued to be operated based on the output signal of the sensor until the duration reaches the predetermined time.

4. The brake control method according to claim 3, characterized in that, after the number of times the duration has been reset to zero exceeds an upper limit, the reset of the duration is prohibited even if the amount of operation of the brake pedal detected by the sensor changes.

5. A brake device comprising: a sensor for detecting the amount of operation of the brake pedal; a braking mechanism for applying frictional braking force to the vehicle; an actuator for driving the braking mechanism; and a controller for operating the actuator based on an electrical signal output by the sensor, wherein the controller performs the following processes: determining whether the brake pedal is depressed based on the output signal of the sensor; determining whether the ignition switch has been switched off while the brake pedal is depressed; and, if the ignition switch has been switched off while the brake pedal is depressed, continuing to operate the actuator based on the output signal of the sensor even after the ignition switch has been switched off.

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