JP6194291B2 - Vehicle braking system - Google Patents

Description

  Vehicle braking system

In a so-called by-wire brake system, a shut-off valve called a master cut valve is provided in a communication path between a master cylinder and a slave cylinder. In addition, a vehicle behavior stabilization device (such as a VSA (registered trademark) device) mounted on these brake systems individually controls the braking force of each wheel to stabilize the behavior of the vehicle.
Patent Literature 1 discloses a brake device that operates a slave cylinder during control of a yaw moment control device (vehicle behavior stabilization device).

JP 2009-227023 A

When the master cut valve installed on the liquid absorption flow path side of the vehicle behavior stabilization device is opened and the vehicle behavior stabilization device is activated without operating the slave cylinder, the flow resistance is reduced due to the master cut valve. The liquid absorption performance and pressure increase performance of the pump of the vehicle behavior stabilization device increase.
Therefore, even when the vehicle behavior stabilization device is in operation when the brake pedal is not operated, the master cut valve is closed so that a small hydraulic pressure is generated in the slave cylinder to maintain the pressure in the slave cylinder. A measure called pressurization control is provided to supply brake fluid from the slave cylinder to the vehicle behavior stabilization device.

However, if there is an abnormality in the communication system (CAN: Controller Area Network) in the vehicle, the controller of the by-wire brake system cannot detect the pressurization state of the vehicle behavior stabilization device. Can be considered. In this case, there is a problem that the pressurization control cannot be performed during the operation of the vehicle behavior stabilization device.
An object of the present invention is to eliminate a problem when a predetermined abnormality occurs and pressurization control cannot be executed.

The present invention relates to a friction braking force generator that generates a friction braking force in a vehicle by operating a slave cylinder, a master cut valve provided in a communication path between the master cylinder and the slave cylinder, and a friction of wheels. A vehicle behavior stabilization device that individually controls braking force to stabilize the behavior of the vehicle, a first control unit that controls the friction braking force generation unit and the master cut valve, and the vehicle behavior stabilization device A second control unit that controls the first and second control units, when operating the vehicle behavior stabilization device, closes the master cut valve to operate the slave cylinder, and When the slave cylinder is operable when a predetermined abnormality occurs in the braking force generation unit, the vehicle behavior stabilization device is activated when the slave cylinder cannot be operated. A vehicular brake system characterized by instructing the second control unit so as to reduce or prohibit compared to.
According to the present invention, when a predetermined abnormality occurs, the operation of the vehicle behavior stabilization device is prohibited (or reduced), so that the pressurization control by the vehicle behavior stabilization device in a situation where the pressurization control cannot be performed reliably. It is possible to prevent the problem of executing.

In this case, the first control unit continues the operation of the slave cylinder with the master cut valve closed when the predetermined abnormality occurs during the operation of the vehicle behavior stabilization device. You may do it.
ADVANTAGE OF THE INVENTION According to this invention, the hydraulic pressure change in control of the both behavior stabilization apparatus during the action | operation of a vehicle behavior stabilization apparatus can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the malfunction when predetermined abnormality generate | occur | produces and pressurization control cannot be performed can be eliminated.

It is a lineblock diagram showing the outline of the brake system for vehicles concerning one embodiment of the present invention. It is a block diagram which shows the electrical connection of the control system of the braking system for vehicles concerning one Embodiment of this invention. It is a flowchart which shows the content of the process which the 1st control part of the braking system for vehicles concerning one Embodiment of this invention performs.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram illustrating an outline of a vehicle braking system 10 according to the present embodiment.
The vehicle braking system 10 is a device for generating a friction braking force of the vehicle. The vehicular braking system 10 is communicated with an input device 14 including a master cylinder 34 that converts a pedal force input by a driver by operating a brake pedal 12 into a hydraulic pressure (hydraulic pressure) of the brake fluid, and the master cylinder. The slave cylinder 16 serving as an actuator for driving the by-wire brake by generating the brake fluid pressure in accordance with the brake fluid pressure generated at 34 or independently of the brake fluid pressure, the vehicle behavior stabilization device ( VSA (registered trademark) device) 18, disc brake mechanisms 30a to 30d, and the like. The slave cylinder 16 includes first and second slave pistons 77a and 77b that receive the driving force of the motor 72 and generate brake fluid pressure.

Master cut valves 60a and 60b, which are electromagnetic valves for opening and closing the pipes, are provided on the pipes 22a and 22d that are communication paths between the master cylinder 34 and the slave cylinder 16.
The vehicle behavior stabilization device 18 includes a motor M and a brake fluid pressurizing pump 73.
The pipes 22a to 22f are provided with brake fluid pressure sensors Pm, Pp, and Ph that detect the brake fluid pressure of each part.

The slave cylinder 16 (via the vehicle behavior stabilization device 18) includes a wheel cylinder 32FR that generates a friction braking force by hydraulic pressure by a disc brake mechanism 30a provided on a right front wheel of a vehicle (not shown), and a left rear wheel. A wheel cylinder 32RL that generates friction braking force by hydraulic pressure in the provided disc brake mechanism 30b, a wheel cylinder 32RR that generates friction braking force by hydraulic pressure in the disc brake mechanism 30c provided in the right rear wheel, and a left front wheel A wheel cylinder 32FL that generates a friction braking force by hydraulic pressure is connected to a disc brake mechanism 30d provided in the vehicle.
A friction braking force generator that generates friction braking force on the vehicle is realized by a device that operates as a by-wire type brake system such as the master cylinder 34, the slave cylinder 16, and the master cut valves 60a and 60b of the vehicle braking system 10. doing.

Next, the basic operation of the vehicle braking system 10 will be described.
In the vehicular braking system 10, when a driver steps on the brake pedal 12 during normal operation of a control system (such as a first control unit 110 described later) that controls the slave cylinder 16 and the by-wire, a so-called buy / The wire brake system is activated. Specifically, in the vehicle braking system 10 during normal operation, when the driver steps on the brake pedal 12 (detected by a brake pedal stroke sensor (not shown)), the first cutoff valve 60a and the second cutoff valve respectively called master cut valves are detected. With the shutoff valve 60b shutting off the communication between the master cylinder 34 and the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL) for braking each wheel, the slave cylinder 16 is driven by the motor 72. The disc brake mechanisms 30a to 30d are operated using the generated brake fluid pressure to brake each wheel.

  During normal operation, the master cut valve (first shutoff valve) 60a and the master cut valve (second shutoff valve) 60b are shut off, while the third shutoff valve 62 is opened, and the brake fluid is supplied to the master cylinder. 34 flows into the stroke simulator 64, and even if the first shut-off valve 60a and the second shut-off valve 60b are shut off, the brake fluid moves, and a stroke occurs when the brake pedal 12 is operated, resulting in a pedal reaction force. It becomes like this.

  On the other hand, in the vehicular braking system 10, when the driver steps on the brake pedal 12 in an abnormal state where the slave cylinder 16 or the like is inoperative, the existing hydraulic brake system becomes active. Specifically, in the vehicle braking system 10 at the time of abnormality, when the driver steps on the brake pedal 12, the master cut valve 60a and the master cut valve are opened, and the third cutoff valve 62 is closed. As a state, the brake hydraulic pressure generated in the master cylinder 34 is transmitted to the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL), and the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL) is actuated to brake each wheel. That is, in this case, the vehicle braking system 10 can be operated as a conventional brake.

  The vehicle behavior stabilization device 18 individually drives the disc brake mechanisms 30a to 30d (wheel cylinders 32FR, 32RL, 32RR, 32FL) by the brake fluid pressurizing pump 73 driven by the motor M, and individually frictions each wheel. By applying a braking force, the behavior of the vehicle is stabilized. For example, an ABS (Antilock Brake System) or the like is also realized by the vehicle behavior stabilization device 18.

Next, control of the vehicle braking system 10 will be described.
FIG. 2 is a block diagram showing the electrical connection of the control system of the vehicle braking system 10. The first control unit 110 controls the slave cylinder 16 and the master cut valves 60a and 60b, which are devices that operate the vehicle braking system 10 as a by-wire brake system (friction braking force generation unit). It is.

The first control unit 110 includes a master cut valve control unit 111 that controls opening and closing of the master cut valves 60a and 60b, a slave cylinder control unit 112 that controls the slave cylinder 16 (motor 72), and a predetermined abnormality described later. The abnormality determination unit 113 that determines whether or not the occurrence of the occurrence of the problem is provided, and the instruction unit 114 that issues an instruction to the second control unit 120.
The second control unit 120 is a control device that controls the vehicle behavior stabilization device 18. Further, the second control unit 120 performs control in accordance with an instruction from the instruction unit 114 of the first control unit 110.

Next, the content of the process which the 1st control part 110 performs is demonstrated.
FIG. 3 is a flowchart showing the contents of processing executed by the first control unit 110. First, the abnormality determination unit 113 determines whether there is any abnormality regarding the control of the by-wire type brake system (S1). When there is no abnormality (No in S1), the instruction unit 114 transmits an operation permission command for permitting the operation of the vehicle behavior stabilization device 18 to the second control unit 120 (S2). Thereby, the vehicle behavior stabilization apparatus 18 can operate | move as needed.

When the vehicle behavior stabilization device 18 is activated by the second control unit 120 (Yes in S3), the master cut valve control unit 111 closes the master cut valves 60a and 60b, and the slave cylinder control unit 112 The slave cylinder 16 is actuated (S4).
More specifically, when the master cut valves 60a and 60b are opened and the vehicle behavior stabilizing device 18 is operated without operating the slave cylinder 16, the flow paths are caused by the master cut valves 60a and 60b. Resistance will increase and the liquid absorption performance and pressure | voltage rise performance of the pump 73 of the vehicle behavior stabilization apparatus 18 will fall.

  Therefore, even when the vehicle behavior stabilizing device 18 is operated when the brake pedal 12 is not operated, the master cut valves 60a and 60b are closed, and a small hydraulic pressure is generated in the slave cylinder 16 so that the pressure in the slave cylinder 16 is increased. It is the process of S4 to perform “pressurization control” which is control for supplying brake fluid from the slave cylinder 16 to the vehicle behavior stabilization device 18 by maintaining.

  On the other hand, when the abnormality determination unit 113 determines that there is some abnormality related to the control of the by-wire type brake system (Yes in S1), the abnormality determination unit 113 determines that the abnormality is capable of operating the slave cylinder 16. It is determined whether or not there is an abnormality (S5). As an abnormality that can operate the slave cylinder 16, one example is a CAN (Controller) used for communication of each part in the vehicle such as communication between the first control unit 110 and the second control unit 120. This is because a failure has occurred in the first control unit 110 for communication via the area network. In another example, the disc brake mechanisms 30a to 30d connected to the vehicle behavior stabilization device 18 are divided into two systems (disc brake mechanisms 30a and 30b and disc brake mechanisms 30c and 30d) as shown in FIG. However, there is a leak in either one of the systems. Even if these abnormalities occur, the operation of the by-wire type brake system is possible.

  When it is a predetermined abnormality that can operate these slave cylinders 16 (Yes in S5), when the vehicle behavior stabilization device 18 is not in operation (No in S6), the instruction unit 114 is the second control unit. An “operation prohibition command” that is a command for prohibiting the operation of the vehicle behavior stabilization device 18 is transmitted to 120 (S7). In this case, the operation amount of the vehicle behavior stabilization device 18 may be reduced before the operation prohibition command is transmitted, instead of completely prohibiting the operation of the vehicle behavior stabilization device 18.

That is, when a communication failure or the like occurs due to CAN, the first control unit 110 cannot detect the state of pressurization generated by the vehicle behavior stabilization device 18. Then, the pressurization control (Yes in S3, S4) of the vehicle behavior stabilization device 18 cannot be executed.
When pressurization control by the vehicle behavior stabilization device 18 is executed in a state where pressurization control is not possible, the brake fluid moves from the upstream side (master cut valve 60a, 60b side) to the downstream side, and the downstream fluid amount increases. .

When the pressure control by the vehicle behavior stabilization device 18 is performed in a state where the fluid amount on the downstream side is increased in this way, the characteristic of the fluid pressure of the slave cylinder 16 with respect to the stroke amount of the slave cylinder 16 is different from the normal case. Therefore, the controllability of the hydraulic pressure of the by-wire type brake system is deteriorated.
Therefore, in order to prevent such deterioration of the controllability of the hydraulic pressure, the operation of the vehicle behavior stabilization device 18 is prevented (or reduced) in a state where the pressurization control (Yes in S3, S4) cannot be performed reliably. (S7).

On the other hand, when the abnormality determination unit 113 determines that the abnormality (Yes in S1) is such that the slave cylinder 16 is not operable (No in S5), the instruction unit 114 displays the second control unit 120. Then, an “operation permission command” that is a command for permitting the operation of the vehicle behavior stabilization device 18 is transmitted (S8).
In such a case, the master cut valves 60a and 60b are opened, and the vehicle braking system 10 operates as a conventional brake.
Further, when an abnormality that can operate the slave cylinder 16 occurs during operation of the vehicle behavior stabilization device 18 (Yes in S1, Yes in S5, Yes in S6), the master cut valves 60a and 60b are kept closed. The operation of the slave cylinder 16 is also maintained (S9).

  As described above, the vehicle braking system 10 determines the operation of the vehicle behavior stabilization device 18 when the abnormality (Yes in S1) is an abnormality that can operate the slave cylinder 16 (Yes in S5). Prevent (or reduce) (S7). Thereby, the malfunction which performs the pressurization control by the vehicle behavior stabilization apparatus 18 in the condition where pressurization control cannot be performed reliably can be prevented.

  Further, when an abnormality occurs during operation of the vehicle behavior stabilization device 18 (Yes in S1, Yes in S5, Yes in S6), the vehicle braking system 10 maintains the master cut valves 60a and 60b closed. The operation of the slave cylinder 16 is also maintained (S9). Therefore, it is possible to prevent a change in hydraulic pressure in the control of the behavior stabilization device 18 during operation of the vehicle behavior stabilization device 18.

10 Vehicle braking system 16 Slave cylinder (friction braking force generator)
18 Vehicle Behavior Stabilizing Device 34 Master Cylinder 60a, 60b Master Cut Valve 110 First Control Unit 120 Second Control Unit

Claims (2)

A friction braking force generator for generating a friction braking force on the vehicle by operating the slave cylinder;
A master cut valve provided in a communication path between the master cylinder and the slave cylinder;
A vehicle behavior stabilization device that generates friction braking force independently of the slave cylinder, and individually controls the friction braking force of wheels to stabilize the behavior of the vehicle;
A first controller that controls the friction braking force generator and the master cut valve;
A second control unit for controlling the vehicle behavior stabilization device,
The first control unit closes the master cut valve to operate the slave cylinder when operating the vehicle behavior stabilization device, and when a predetermined abnormality occurs in the friction braking force generation unit When the slave cylinder is operable, the second control unit is instructed to reduce or prohibit the operation of the vehicle behavior stabilization device as compared with the case where the slave cylinder cannot be operated. Vehicle braking system.   The first control unit continues the operation of the slave cylinder with the master cut valve closed when the predetermined abnormality occurs during the operation of the vehicle behavior stabilization device. The vehicle braking system according to claim 1.

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