JP2022155868A - vehicle braking device - Google Patents

Abstract

To provide a vehicle braking device which can vary displacement-force characteristics of a brake pedal without enlarging the device.SOLUTION: The vehicle braking device of the invention comprises: liquid passages 5 which connect a master cylinder 21, an electric cylinder 3, and a wheel cylinder 4; a valve part 6 constituted to be able to open and close a master connection between the electric cylinder 3 and the master cylinder 21 and a wheel connection between the electric cylinder 3 and the wheel cylinder 4 through the liquid passages 5; and a control part 7 constituted to be able to perform master pressure control for actuating the electric cylinder 3 to adjust liquid pressure of the master cylinder 21 under a condition that the master connection is opened, and the wheel connection closed by the valve part 6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle braking system.

For example, Japanese Patent No. 5800437 discloses a braking device that includes an electric cylinder, a wheel cylinder, and a reservoir. In this braking device, when the piston position exceeds a predetermined position, the solenoid valve between the electric cylinder and the wheel cylinder is closed, and the piston is driven in the direction of the initial position, thereby draining the brake fluid from the reservoir. Inhalation control is performed to inhale.

Japanese Patent No. 5800437

The braking device incorporates a mechanism that applies a reaction force to the brake pedal when the driver operates the brake. In this mechanism, the relationship between the displacement of the brake pedal and the reaction force (hereinafter also referred to as "displacement-force characteristic") is set depending on the structure and the like. The braking device described above does not disclose a technique for making the displacement-force characteristic variable. If the displacement-force characteristic is made variable, for example, a dedicated electric motor is required to generate an adjustment force to the brake pedal, which raises concerns about an increase in the size of the device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle braking device capable of varying the displacement-force characteristics of a brake pedal without increasing the size of the device.

A vehicle braking device according to the present invention includes a fluid path connecting a master cylinder, an electric cylinder, and a wheel cylinder, a master connection that connects the electric cylinder and the master cylinder through the fluid path, and the electric cylinder. a valve portion configured to be able to open and close a wheel connection that is a connection with a wheel cylinder; and with the valve portion opening the master connection and closing the wheel connection, the electric cylinder is operated. and a control unit that executes master pressure control for adjusting the hydraulic pressure of the master cylinder.

According to the present invention, brake fluid can be supplied from the electric cylinder to the master cylinder by controlling the master pressure. As a result, the hydraulic pressure in the master cylinder increases, and the value (characteristic) of the reaction force with respect to the displacement of the brake pedal changes. In order to change the displacement-force characteristics of the brake pedal, an electric cylinder necessary for pressurizing and depressurizing the wheel cylinder is used, so there is no need to install a dedicated electric motor, etc., and an increase in the size of the device can be avoided. That is, one electric cylinder can have two functions, a wheel pressure adjusting function and a master pressure adjusting function. According to the present invention, the displacement-force characteristics of the brake pedal can be made variable without increasing the size of the device.

1 is a configuration diagram of a vehicle braking device according to a first embodiment; FIG. It is a block diagram of the braking device for vehicles of 2nd Embodiment. It is an explanatory view for explaining a valve part of a modification of this embodiment.

An embodiment of the present invention will be described below with reference to the drawings. In addition, in each of the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings. Each figure used for explanation is a conceptual diagram.

<First Embodiment>
A vehicle braking system 1 of the first embodiment includes a master cylinder device 2 , an electric cylinder 3 , a wheel cylinder 4 , a fluid passage 5 , a valve portion 6 and a control portion 7 . The master cylinder device 2 is a device that supplies brake fluid to the fluid path 5 in accordance with the operation of the brake pedal 9 by the driver. The master cylinder device 2 includes a master cylinder 21 , a master piston 22 , a biasing member 23 and a reservoir 24 .

The master cylinder 21 is a bottomed cylindrical cylinder member. The master piston 22 is arranged inside the master cylinder 21 and slides inside the master cylinder 21 according to the operation of the brake pedal 9 . A master chamber 21 a defined by the inner peripheral surface of the master cylinder 21 and the master piston 22 is formed in the master cylinder 21 . In the description, the moving direction in which the master piston 22 moves so as to reduce the volume of the master chamber 21a is defined as "forward".

The biasing member 23 is a spring that biases the master piston 22 toward the initial position. The biasing member 23 is arranged in the master chamber 21a. The initial position is the position where the volume of the master chamber 21a is maximized. An input port 211 and an output port 212 are formed in the master cylinder 21 . The input port 211 is a port that connects the master chamber 21 a and the reservoir 24 via the liquid path 241 . A normally open solenoid valve 25 is arranged in the liquid path 241 of this example. The output port 212 is a port that connects the master chamber 21 a and the liquid path 5 .

The master piston 22 is configured to close the input port 211 and cut off the connection between the master chamber 21 a and the reservoir 24 when the master piston 22 is advanced by a predetermined amount from the initial position due to the braking operation. When the master piston 22 moves forward while the master chamber 21 a and the reservoir 24 are blocked, the brake fluid in the master chamber 21 a is output to the fluid passage 5 through the output port 212 . The solenoid valve 25 is not actuated except under certain circumstances, and normally the fluid path 241 is kept open (communicated).

A simulator cut valve 82 and a stroke simulator 83 are connected to the output port 212 via a fluid path 81 branched from the fluid path 5 . A branch point at which the fluid path 81 branches from the fluid path 5 is formed in a portion of the fluid path 5 closer to the master cylinder 21 than the valve portion 6 (first fluid path 51 to be described later).

When the simulator cut valve 82 is open and the master cylinder 21 is cut off from the electric cylinder 3 and the wheel cylinder 4 by the valve portion 6, the brake fluid output from the output port 212 flows into the stroke simulator 83. . The stroke simulator 83 is composed of a cylinder 831, a piston 832, and an urging member 833, and applies hydraulic pressure to the operation of the brake pedal 9 as a reaction force.

The electric cylinder 3 is a device that can pressurize and depressurize the liquid path 5 . The electric cylinder 3 includes a cylinder 31 , a piston 32 , a biasing member 33 and an electric motor 34 . The cylinder 31 is a bottomed cylindrical cylinder member (part). The piston 32 is arranged inside the cylinder 31 and slides inside the cylinder 31 by the power of the electric motor 34 . An output chamber 31 a defined by the inner peripheral surface of the cylinder 31 and the piston 32 is formed in the cylinder 31 .

An input port 311 and an output port 312 are formed in the cylinder 31 . The input port 311 is a port that connects the output chamber 31 a and the reservoir 24 via the liquid path 242 . The output port 312 is a port that connects the output chamber 31 a and the liquid path 5 . In the description, the moving direction in which the piston 32 moves so as to reduce the volume of the output chamber 31a is defined as "forward".

The piston 32 is configured to close the input port 311 and cut off the connection between the output chamber 31 a and the reservoir 24 when the piston 32 is advanced by a predetermined amount from the initial position by the power of the electric motor 34 . When the piston 32 moves forward while the output chamber 31 a and the reservoir 24 are blocked, the brake fluid in the output chamber 31 a is output to the fluid path 5 through the output port 312 . The initial position of the piston 32 is the position where the volume of the output chamber 31a is maximized.

The biasing member 33 is a spring arranged in the output chamber 31a. The biasing member 33 biases the piston 32 toward the initial position. The electric motor 34 is controlled by the control unit 7 and applies power to the piston 32 via a linear motion converting mechanism 34a having a speed reducer. The rotary motion of the output shaft of the electric motor 34 is converted into the linear motion of the piston 32 by the linear motion conversion mechanism 34a. The wheel cylinder 4 is provided on the wheel and applies a braking force to the wheel according to the hydraulic pressure. The foil cylinder 4 is connected to the liquid passage 5 .

The fluid path 5 is a fluid path that connects the master cylinder 21 , the electric cylinder 3 and the wheel cylinder 4 . More specifically, the fluid path 5 includes a first fluid path 51 connecting the master cylinder 21 and the valve portion 6, a second fluid path 52 connecting the electric cylinder 3 and the valve portion 6, and a wheel cylinder 4 and the valve portion. 6 is configured with a third liquid passage 53 that connects the . That is, the fluid passage 5 connects the master cylinder 21 , the electric cylinder 3 and the wheel cylinder 4 via the valve portion 6 .

The valve part 6 is a valve mechanism provided in the liquid path 5 and is composed of one or a plurality of valves. The valve part 6 can open and close the master connection, which is the connection between the electric cylinder 3 and the master cylinder 21, and the wheel connection, which is the connection between the electric cylinder 3 and the wheel cylinder 4, through the liquid path 5 (connection/disconnection switchable). ). That is, the valve portion 6 can switch the output destination of the electric cylinder 3 between the master cylinder 21 and the wheel cylinder 4 .

The master connection is composed of the first fluid path 51 , the valve portion 6 and the second fluid path 52 . The foil connection is made up of the second fluid path 52 , the valve portion 6 and the third fluid path 53 . The valve portion 6 is, for example, a three-way valve (also called a flow path switching valve), and is a valve that can discharge the fluid that has entered through one of the holes in either of two directions. The valve portion 6 is operated under the control of the control portion 7 and the flow path is switched by the control portion 7 .

The control unit 7 is an electronic control unit (ECU) including a processor, memory, and the like. The control unit 7 is communicably connected to a plurality of devices. Specifically, the control unit 7 controls the electric cylinder 3 (electric motor 34 ), the valve unit 6 , the simulator cut valve 82 and the electromagnetic valve 25 . The control unit 7 receives detection information (for example, the operation amount of the brake pedal 9, the hydraulic pressure in the output chamber 31a, the hydraulic pressure in the master chamber 21a, etc.) from a stroke sensor and a pressure sensor (not shown).

(Master pressure control and wheel pressure control)
The control unit 7 operates the electric cylinder 3 to adjust the hydraulic pressure of the master cylinder 21 in a state in which the master connection is opened (communicated) and the wheel connection is closed (disconnected) by the valve unit 6 . It is configured to be able to perform pressure control. During master pressure control, the controller 7 opens the simulator cut valve 82 . Further, the control unit 7 executes the master pressure control while the master cylinder 21 and the reservoir 24 are disconnected. For example, when the master piston 22 is at the initial position, the controller 7 closes the solenoid valve 25 and then executes the master pressure control.

In addition, the control unit 7 operates the electric cylinder 3 in a state in which the valve unit 6 closes the master connection and opens the wheel connection, thereby executing wheel pressure control to adjust the hydraulic pressure of the wheel cylinder 4. configured as possible. The controller 7 is configured to be switchable between master pressure control and wheel pressure control. The control unit 7 switches between master pressure control and wheel pressure control depending on the situation.

The control unit 7 executes wheel pressure control in response to an operation of the brake pedal 9 or a braking request by automatic brake control or the like, and pressurizes or depressurizes the wheel cylinder 4 by operating the electric cylinder 3 . Wheel pressure control is performed in a state in which communication between the master cylinder 21 and the wheel cylinder 4 is disconnected, and can be called brake-by-wire control. In wheel pressure control, anti-skid control (ABS control) and skid prevention control (ESC) can be executed.

For example, when receiving an instruction to change the brake feeling or an instruction to haptic vibration, the control unit 7, at a predetermined timing, for example, in a state where the wheel pressure is held (a state in which the braking request value is constant) or in a stopped state, Execute master pressure control. In master pressure control, the control unit 7 operates the electric cylinder 3 to supply brake fluid from the electric cylinder 3 to the master cylinder 21 and the stroke simulator 83 .

The master pressure control pushes the piston of the stroke simulator 83 and changes the displacement-force characteristics of the brake pedal 9 . In other words, when the piston of the stroke simulator 83 is pushed in, the displacement of the displacement-force characteristic of the brake pedal 9 increases accordingly. The reaction force of the brake pedal 9 increases, and the amount of change in the force (reaction force) per unit displacement can also be changed. During master pressure control, the wheel cylinder 4 is closed (the third fluid passage 53 is closed), and the fluid pressure in the wheel cylinder 4 is maintained.

(Effect of the first embodiment)
According to the first embodiment, brake fluid can be supplied from the electric cylinder 3 to the master cylinder 21 by master pressure control. As a result, the hydraulic pressure in the master cylinder 21 increases, and the value (characteristic) of the reaction force with respect to the displacement of the brake pedal 9 changes. In order to change the displacement-force characteristics of the brake pedal 9, since the electric cylinder 3 necessary for pressurizing and depressurizing the wheel cylinder 4 is used, there is no need to install a dedicated electric motor, etc., and an increase in the size of the device is avoided. be done. That is, one electric cylinder 3 can be provided with two functions, a wheel pressure adjusting function and a master pressure adjusting function. According to the first embodiment, the displacement-force characteristics of the brake pedal 9 can be made variable without increasing the size of the device.

Further, it is possible to switch between wheel pressure control and master pressure control by a simple control of switching the connection state by the valve portion 6 . The control unit 7 can perform wheel pressure control during normal brake control, and can perform master pressure control when necessary. When necessary, for example, when changing the brake feeling (for example, sport mode), or when vibrating the brake pedal 9 with hydraulic pressure to send some signal to the driver.

(Modification)
In the vehicle braking system 1 , a direct connection between the master cylinder 21 and the wheel cylinder 4 can be constructed by the valve portion 6 and the fluid passage 5 . The valve portion 6 is configured to open the direct connection and close the master connection and the wheel connection in the event of a power failure or the like in which power is not supplied to the valve portion 6 or the electric cylinder 3, for example. The direct connection is composed of the first fluid path 51 , the valve portion 6 and the third fluid path 53 .

In this case, the control unit 7 operates the electric cylinder 3 to adjust the hydraulic pressure of the master cylinder 21 in a state in which the valve unit 6 opens the master connection and closes the wheel connection and the direct connection. It is configured to be able to perform pressure control. Further, the control unit 7 operates the electric cylinder 3 to adjust the hydraulic pressure of the wheel cylinder 4 in a state in which the master connection and the direct connection are closed by the valve unit 6 and the wheel connection is opened. It is configured so that control can be executed.

Also, the electromagnetic valve 25 may be omitted (the same applies to the second embodiment described later). Without the solenoid valve 25, the master pressure control is executed with the master piston 22 advanced by a predetermined amount or more from the initial position. When the control unit 7 detects that the master cylinder 21 and the reservoir 24 are disconnected based on the detection values of various sensors, the control unit 7 enables master pressure control.

<Second embodiment>
In contrast to the vehicle braking system 1 of the first embodiment, the vehicle braking system 1A of the second embodiment includes a second electric cylinder 3A, a second wheel cylinder 42, and a fourth fluid path ("pressure regulating fluid path"). ) 54 , a communication passage 55 and a communication control valve 56 are added. Therefore, the added part will be mainly described below. Also, in the description, the wheel cylinder 4 of the first embodiment is referred to as the first wheel cylinder 41 and the electric cylinder 3 of the first embodiment is referred to as the first electric cylinder 3 . In the description of the second embodiment, the description and drawings of the first embodiment can be referred to as appropriate.

The second electric cylinder 3A has the same configuration as the first electric cylinder 3, and the reference numerals of the components of the first electric cylinder 3 are appended with "A" (for distinction) to omit the description. Input port 311A is connected to reservoir 24 or another reservoir (not shown). The output port 312A is connected to the second wheel cylinder 42 via the fourth fluid passage 54. As shown in FIG. The fourth fluid path 54 is a fluid path that connects the second electric cylinder 3A and the second wheel cylinder 42 .

The communication path 55 is a fluid path that connects the fourth fluid path 54 and the third fluid path 53 (that is, the portion of the fluid path 5 between the valve portion 6 and the first wheel cylinder 41). The communication control valve 56 is an electromagnetic valve provided in the communication path 55 . The communication control valve 56 is a normally open electromagnetic valve, and is configured to open and close the communication path 55 (communication/shutdown switching). The communication control valve 56 can also be said to be part of the valve section 6 . The valve portion 6 includes a connection between the first electric cylinder 3 and the master cylinder 21 as a master connection, a connection between the first electric cylinder 3 and the first wheel cylinder 41 as a wheel connection, and a first wheel It can be said that the inter-wheel connection between the cylinder 41 and the second wheel cylinder 42 can be opened and closed.

In normal brake control (wheel pressure control), the communication control valve 56 is closed when the pressures of the first wheel cylinder 41 and the second wheel cylinder 42 are independently adjusted (pressurized and depressurized). When adjusting the wheel cylinders 41 and 42 at the same pressure, the communication control valve 56 may be opened. The control unit 7 executes wheel pressure control based on the braking request, for example, with the communication control valve 56 closed, pressurizes and depressurizes the first wheel cylinder 41 by operating the first electric cylinder 3, The second wheel cylinder 42 is pressurized and depressurized by the operation of the cylinder 3A.

Further, the control unit 7 operates the first electric cylinder 3 to change the hydraulic pressure of the master cylinder 21 in a state in which the master connection is opened and the wheel connection is closed by the valve unit 6, as in the first embodiment. is configured to be able to execute master pressure control that adjusts the Furthermore, the control unit 7 opens the communication control valve 56 during execution of the master pressure control, and performs pressure adjustment control for increasing or decreasing the first wheel cylinder 41 and the second wheel cylinder 42 by operating the second electric cylinder 3A. is configured to be executable. In other words, the control unit 7 adjusts the hydraulic pressures of the first wheel cylinder 41 and the second wheel cylinder 42 by actuating the second electric cylinder 3A while the inter-wheel connection is released during master pressure control. It is configured to be able to execute pressure regulation control.

Thus, the vehicle braking system 1A of the second embodiment includes the first electric cylinder 3, which is the electric cylinder 3 of the first embodiment, the second electric cylinder 3A different from the first electric cylinder 3, and the second electric cylinder 3A. A first wheel cylinder 41 that is the wheel cylinder 4 of one embodiment, a second wheel cylinder 42 that is different from the first wheel cylinder 41, and a valve that can open and close the master connection, the wheel connection, and the inter-wheel connection. and a controller 7 configured to be able to perform pressure regulation control while master pressure control is being performed. More specifically, the vehicle braking device 1A includes a first electric cylinder 3, a second electric cylinder 3A, a first wheel cylinder 41, a second wheel cylinder 42, a second electric cylinder 3A, and a second wheel cylinder 42. and the fourth fluid path 54 and the portion of the fluid path 5 between the valve portion 6 and the first wheel cylinder 41 (that is, the third fluid path 53). It includes a passage 55, a communication control valve 56 which is an electromagnetic valve provided in the communication passage 55, and a control section 7 capable of performing pressure regulation control. According to the second embodiment, in addition to the effects of the first embodiment, it is possible to adjust the hydraulic pressures of the wheel cylinders 41 and 42 even during master pressure control.

<Others>
The present invention is not limited to the first and second embodiments described above. For example, as shown in FIG. 3, the valve section 6 is not limited to a three-way valve, and may be composed of two electromagnetic valves 61 and 62. As shown in FIG. The solenoid valve 61 is a normally open solenoid valve provided in the first liquid passage 51 . The solenoid valve 62 is a normally open solenoid valve provided in the third liquid passage 53 . Even with this configuration, the supply destination of the brake fluid from the electric cylinder 3 can be switched between the wheel cylinder 4 and the master cylinder 21 . Also, the electromagnetic valve 25 may be omitted. These are the same not only in the first embodiment but also in the second embodiment. In the second embodiment, the valve section 6 may include, for example, the three-way valve and the communication control valve 56, or may include the solenoid valves 61, 62 and the communication control valve 56. When performing master pressure control, the controller 7 opens the solenoid valve 61 and closes the solenoid valve 62 . Further, when executing wheel pressure control, the control unit 7 closes the electromagnetic valve 61 and opens the electromagnetic valve 62 . If the direct connection can be performed, a normally closed solenoid valve may be provided in the second fluid path 52 as a component of the valve portion 6, for example.

DESCRIPTION OF SYMBOLS 1, 1A... Vehicle braking device, 2... Master cylinder apparatus, 21... Master cylinder, 3, 3A... Electric cylinder, 4... Wheel cylinder, 41... First wheel cylinder, 42... Second wheel cylinder, 5... Fluid path , 54... Fourth fluid path (pressure regulating fluid path), 55... Communication path, 56... Communication control valve, 6... Valve section, 7... Control section.

Claims (3)

a fluid path connecting the master cylinder, the electric cylinder, and the wheel cylinder;
a valve portion configured to be able to open and close a master connection, which is a connection between the electric cylinder and the master cylinder, and a wheel connection, which is a connection between the electric cylinder and the wheel cylinder, through the liquid passage;
In a state in which the master connection is opened and the wheel connection is closed by the valve portion, the electric cylinder is operated to perform master pressure control for adjusting the hydraulic pressure of the master cylinder. a control unit;
A vehicle braking device. The control unit operates the electric cylinder to adjust the hydraulic pressure of the wheel cylinder in a state in which the master connection is closed and the wheel connection is opened by the valve unit; 2. The vehicle brake system according to claim 1, configured to be switchable with said master pressure control. a first electric cylinder, which is the electric cylinder;
a second electric cylinder different from the first electric cylinder;
a first wheel cylinder, which is the wheel cylinder;
a second wheel cylinder separate from the first wheel cylinder;
with
The valve portion includes a connection between the first electric cylinder and the master cylinder as the master connection, a connection between the first electric cylinder and the first wheel cylinder as the wheel connection, and the A connection between the wheels, which is a connection between the first wheel cylinder and the second wheel cylinder, can be opened and closed,
The control unit adjusts hydraulic pressures of the first wheel cylinder and the second wheel cylinder by operating the second electric cylinder while the inter-wheel connection is opened during execution of the master pressure control. 3. The vehicular braking system according to claim 1, configured to be capable of executing pressure regulation control.

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