Vehicle Brake Device

Abstract

To provide a vehicular braking apparatus capable of improving the foreign matter removal performance of removing foreign matter inside an electromagnetic valve.SOLUTION: A vehicular braking apparatus includes: a stroke simulator 43; a pressurizing / depressurizing device 2 connected to the stroke simulator 43 via a liquid passage 500 and capable of pressurizing / depressurizing the liquid passage 500 without depending on a driver's operation; object electromagnetic valves 44, 61, 62 that are electromagnetic valves provided in the liquid passage 500; and a control unit 91 for executing refreshing control in which the pressurizing / depressurizing device 2 is made to execute pressurizing processing for pressurizing the stroke simulator 43 and the liquid passage 500 while the object electromagnetic valves 44, 61, 62 are opened, and then to execute depressurizing processing for depressurizing the liquid passage 500, thereby causing fluid to flow from the stroke simulator 43 toward the object electromagnetic valves 44, 61, 62.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a braking system for a vehicle. [Background technology]

[0002] Conventionally, vehicle braking systems have performed air bleeding control to bleed air from the brake circuit, as described in, for example, German Patent Application Publication No. 102017211874. In this system, the fluid path is pressurized by an electric cylinder while the solenoid valve connecting the master cylinder and the reservoir is closed, and then the solenoid valve is opened to control the fluid in the fluid path to flow into the reservoir together with the air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102017211874 Summary of the Invention [Problem to be solved by the invention]

[0004] While the above control is effective in removing air, it may not be possible to ensure a sufficient flow rate to remove foreign matter from the fluid path, particularly foreign matter that has entered the solenoid valve. If foreign matter enters the solenoid valve, it may fail to close. The above device has room for improvement in terms of removing foreign matter from the solenoid valve.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle braking system that can improve the foreign matter removal performance for removing foreign matter from inside a solenoid valve. [Means for solving the problem]

[0006] The vehicle braking system of the present invention comprises a stroke simulator having a cylinder and a piston biased toward an initial position by a biasing member provided inside the cylinder, and wherein when fluid is supplied from a fluid passage connected to the cylinder, the piston moves away from the initial position against the biasing force of the biasing member; a pressurizing / depressurizing device connected to the stroke simulator via the fluid passage across a target solenoid valve which is an electromagnetic valve provided in the fluid passage, and configured to pressurize or depressurize the fluid passage without the driver's operation by supplying fluid to or discharging fluid from the fluid passage; and a control unit that performs refresh control by having the pressurizing / depressurizing device perform a pressurization process to pressurize the stroke simulator and the fluid passage with the target solenoid valve open, and then performing a depressurization process to depressurize the fluid passage, thereby causing fluid to flow from the stroke simulator toward the target solenoid valve. [Effects of the Invention]

[0007] According to the present invention, when the target solenoid valve is open, pressurizing the stroke simulator causes the piston to move away from its initial position. The fluid path is then depressurized, forcing the fluid from the stroke simulator into the fluid path and flowing toward the target solenoid valve. The fluid in the fluid path flows away from the stroke simulator, and is further subjected to a force caused by the stroke simulator's piston returning to its initial position. This increases the flow rate (flow velocity) of the fluid flowing from the stroke simulator toward the target solenoid valve. Therefore, foreign matter in the target solenoid valve is more easily removed from the target solenoid valve by the fluid gaining momentum. According to the present invention, the foreign matter removal performance for removing foreign matter in the solenoid valve can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a vehicle braking device according to an embodiment of the present invention; [Figure 2] 4 is a flowchart of a first refresh control according to the present embodiment. [Figure 3]10 is a flowchart of a modified example of the first refresh control of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a vehicle braking system 1 of this embodiment includes an upstream unit 11, a downstream unit 3, a first brake ECU 901, and a second brake ECU 902. The vehicle braking system 1 is a device that can supply fluid to wheel cylinders 81, 82, 83, and 84 provided on the wheels of the vehicle. The first brake ECU 901 controls at least the upstream unit 11. The second brake ECU 902 controls at least the downstream unit 3.

[0010] (Upstream unit) The upstream unit 11 includes a master cylinder device 4, a stroke simulator 43, a simulator cut valve 44, a reservoir 45, a first fluid passage 51, an electric cylinder (corresponding to a "pressure-compression device") 2, a second fluid passage 52, a communication passage 53, a fluid passage 54, a master cut valve 62, a system shutoff valve 61, a stroke sensor 71, and pressure sensors 72 and 73. Fig. 1 shows the vehicle braking system 1 in a non-energized state.

[0011] The master cylinder device 4 is a device capable of generating hydraulic pressure in response to driver operation. The master cylinder device 4 includes a master cylinder 41, a master piston 42, a master chamber 41a, and a biasing member 41b. The master cylinder 41 is a cylindrical member with a bottom. An input port 411 and an output port 412 are formed in the master cylinder 41.

[0012] The input port 411 is connected to a reservoir 45 via a reservoir fluid path 40a. A reservoir cutoff valve 40, which is a normally open solenoid valve, is arranged in the reservoir fluid path 40a. When the reservoir cutoff valve 40 is closed, the connection between the master cylinder 41 and the reservoir 45 is cut off. The output port 412 is connected to the downstream unit 3 via a first fluid path 51. The output port 412 is also connected to a portion (fluid path) 40b of the first fluid path 51 and to the stroke simulator 43 via a fluid path 43a.

[0013] The master piston 42 is a piston member disposed within the master cylinder 41 and is mechanically connected to the brake pedal Z. The master piston 42 slides within the master cylinder 41 in response to operation of the brake pedal Z. A through-hole 421 is formed in the master piston 42. The master piston 42 is biased toward its initial position by a biasing member 41b, which will be described later. The initial position is the position of the master piston 42 when the volume of the master chamber 41a is at its maximum. When the master piston 42 is located in the initial position, the through-hole 421 and the input port 411 are in communication.

[0014] The master chamber 41a is formed in the master cylinder 41 by the master cylinder 41 and the master piston 42. In this embodiment, the number of master chambers 41a formed in the master cylinder 41 is one, but two (tandem type) may be formed. The volume of the master chamber 41a changes according to the movement of the master piston 42. When the master piston 42 moves to one side in the axial direction, the volume of the master chamber 41a decreases, and the hydraulic pressure in the master chamber 41a (hereinafter referred to as "master pressure") increases. The biasing member 41b is a spring member provided in the master chamber 41a. When no force is acting on the master piston 42, the master piston 42 is located in its initial position.

[0015] The stroke simulator 43 is connected to the master cylinder 41 via a fluid passage 43a, a simulator cut valve 44 provided in the fluid passage 43a, and a first fluid passage 51. The stroke simulator 43 is a device that generates a reaction force (load) against the operation of the brake pedal Z.

[0016] Specifically, the stroke simulator 43 includes a cylinder 431 and a piston 432 that is biased toward an initial position by a biasing member 433 provided inside the cylinder 431. The stroke simulator 43 is configured so that when a fluid path 43a (fluid path 500, described later) connected to the cylinder 431 is pressurized, the piston 432 moves away from the initial position against the biasing force of the biasing member 433. The biasing member 433 is, for example, a spring. A housing chamber 434 in the cylinder 431 in which the biasing member 433 is disposed is connected to the reservoir 45 by a fluid path 43b. The stroke simulator 43 is connected to the output port 412 of the master cylinder 41 via the fluid path 43a.

[0017] The simulator cut valve 44 is a normally closed solenoid valve provided in the fluid passage 43a. When the brake pedal Z is operated with a master cut valve 62 (described later) closed and the simulator cut valve 44 open, a pedal reaction force is generated by the stroke simulator 43.

[0018] The reservoir 45 stores fluid. The pressure inside the reservoir 45 is maintained at atmospheric pressure. Two storage chambers 451 and 452, each storing fluid, are formed inside the reservoir 45.

[0019] The reservoir chamber 451 is connected to the master cylinder device 4. More specifically, the reservoir chamber 451 is connected to the input port 411 of the master cylinder. When the master piston 42 is located in the initial position, the reservoir chamber 451 is hydraulically connected to the master chamber 41a via the input port 411 and the through-hole 421. When the master piston 42 slides a predetermined amount, the input port 411 and the through-hole 421 are hydraulically blocked. In this case, the master chamber 41a and the reservoir 45 are hydraulically blocked. The reservoir chamber 452 is connected to the electric cylinder 2 via a hydraulic path 54. The reservoir 45 may be composed of two separate reservoirs instead of two reservoirs.

[0020] The first fluid path 51 is a fluid path connecting the master cylinder device 4 and the downstream unit 3. The first fluid path 51 is connected to the master chamber 41a via an output port 412. When the master piston 42 slides to reduce the size of the master chamber 41a while the master chamber 41a and the reservoir 45 are hydraulically isolated, fluid is supplied from the master chamber 41a to the first fluid path 51 via the output port 412, generating hydraulic pressure in the first fluid path 51. The hydraulic pressure generated in the master chamber 41a is supplied to the downstream unit 3 via the first fluid path 51. The first fluid path 51 includes a connection portion 50 connected to a communication path 53, which will be described later. A master cut valve 62 and a pressure sensor 72 are provided in the first fluid path 51.

[0021] The master cut valve 62 is a normally open solenoid valve provided in the first fluid path 51, closer to the master cylinder device 4 than the connection part 50. When the master cut valve 62 is closed, the master cylinder device 4 and the downstream unit 3 are hydraulically isolated from each other.

[0022] The pressure sensor 72 is provided in the first fluid path 51, closer to the master cylinder device 4 than the master cut valve 62. The pressure sensor 72 detects the pressure in the first fluid path 51. When the master cut valve 62 is closed, the pressure detected by the pressure sensor 72 corresponds to the master pressure, which is the pressure generated in the master chamber.

[0023] (electric cylinder) The electric cylinder 2 includes a cylinder 21, an electric motor 22, a piston 23, a hydraulic chamber 24, and a biasing member 25. The electric cylinder 2 is a single-type electric cylinder in which a single hydraulic chamber 24 is formed in the cylinder 21 as an output chamber. In describing the electric cylinder 2 in the present disclosure, the direction in which the piston 23 reduces the size of the hydraulic chamber 24 is referred to as the front, and the direction in which the piston 23 increases the size of the hydraulic chamber 24 is referred to as the rear. This does not have to correspond to the fore-and-aft direction of the vehicle.

[0024] The cylinder 21 is a cylindrical part (or member) with a bottom. An input port 211 and an output port 212 are formed in the cylinder 21. As shown in FIG. 2, the input port 211 is an opening and is formed between two seal members provided in the cylinder 21. The seal members are annular cup seals. The output port 212 is an opening and is formed forward of the input port 211.

[0025] The electric motor 22 is connected to the piston 23 via a linear motion mechanism 22a that converts rotational motion into linear motion. The piston 23 is a cylindrical member with a bottom, and slides within the cylinder 21 when driven by the electric motor 22. A through hole 231 is formed in the piston 23. When the piston 23 is in its initial position, the hydraulic chamber 24 and the input port 211 communicate with each other via the through hole 231.

[0026] The hydraulic chamber 24 is defined by the cylinder 21 and the piston 23, and the volume thereof changes in accordance with the movement of the piston 23. The initial position of the piston 23 is a position where the volume of the hydraulic chamber 24 is maximum. As the piston 23 moves forward, the volume of the hydraulic chamber 24 decreases.

[0027] The hydraulic chamber 24 can communicate with the reservoir 45 via the input port 211. More specifically, when the piston 23 is in the initial position, the hydraulic chamber 24 is hydraulically connected to the reservoir 45 via the through-hole 231, the input port 211, and the hydraulic path 54. When the through-hole 231 and the input port 211 are not in communication, the hydraulic chamber 24 is hydraulically isolated from the reservoir 45. The hydraulic chamber 24 is connected to the second hydraulic path 52 via the output port 212.

[0028] When the piston 23 moves forward a predetermined amount due to the driving of the electric motor 22, communication between the input port 211 and the through-hole 231 is blocked. In this case, the hydraulic chamber 24 is hydraulically blocked from the reservoir 45. When the piston 23 slides to reduce the size of the hydraulic chamber 24 while the hydraulic chamber 24 and the reservoir 45 are hydraulically blocked, fluid is supplied from the hydraulic chamber 24 via the output port 212 to the second hydraulic path 52, generating hydraulic pressure in the second hydraulic path 52.

[0029] The biasing member 25 is a spring that is disposed in the hydraulic chamber 24 and biases the piston 23 toward its initial position. When the electric motor 22 is not driven, the biasing force of the biasing member 25 positions the piston 23 at its initial position.

[0030] The second fluid path 52 is a fluid path that connects the electric cylinder 2 and the downstream unit 3. The fluid pressure generated in the hydraulic chamber 24 is supplied to the downstream unit 3 via the second fluid path 52. A pressure sensor 73 is provided in the second fluid path. The first fluid path 51 and the second fluid path 52 are the portions of the fluid paths that connect the master cylinder device 4 and the downstream unit 3 that are arranged within the upstream unit 11.

[0031] The pressure sensor 73 is a sensor that detects the pressure in the second fluid path 52. When the control mode of the vehicle braking system 1 is a brake-by-wire mode (hereinafter referred to as the "by-wire mode"), which will be described later, the fluid pressure detected by the pressure sensor 73 corresponds to the output pressure of the electric cylinder 2.

[0032] Communication passage 53 is a fluid passage that connects first fluid passage 51 and second fluid passage 52. Communication passage 53 is connected to first fluid passage 51 at connection portion 50. A system shutoff valve 61 is provided in communication passage 53. When system shutoff valve 61 is closed, communication between wheel cylinders 81, 82 of the first system and wheel cylinders 83, 84 of the second system is shut off.

[0033] The system shutoff valve 61 is a normally closed solenoid valve. The valve element of the system shutoff valve 61 is located closer to the first fluid path 51 than the valve seat. Therefore, when the pressure on the first fluid path 51 side in the communication passage 53 is higher than the pressure on the second fluid path 52 side, a force acts on the system shutoff valve 61 in the valve closing direction. As a result, even if the hydraulic pressure in the wheel cylinders 81, 82 becomes higher than the output pressure of the electric cylinder 2 when the system shutoff valve 61 is closed, a force is applied to the valve element in the direction pressing it against the valve seat (self-sealing), so the valve remains closed. The system shutoff valve 61 can also be said to be a communication control valve that controls the connection state between the first fluid path 51 and the second fluid path 52.

[0034] The stroke sensor 71 detects the stroke of the brake pedal Z. In this embodiment, two stroke sensors 71 are provided. Data detected by the two stroke sensors 71 is transmitted to the brake ECUs 901 and 902. The brake ECUs 901 and 902 acquire stroke information from the corresponding stroke sensors 71.

[0035] (Downstream unit) The downstream unit 3 is a so-called ESC actuator, and can independently adjust the hydraulic pressure of each wheel cylinder 81-84. The downstream unit 3 includes a plurality of solenoid valves, a pump, a motor, a reservoir, etc., which are not shown. The downstream unit 3 includes a first hydraulic pressure output section 31 configured to be able to adjust the pressure of the wheel cylinders 81, 82, and a second hydraulic pressure output section 32 configured to be able to adjust the pressure of the wheel cylinders 83, 84. The downstream unit 3 can be said to be a pressurizing device that is provided separately from the electric cylinder 2 and can pressurize the wheel cylinders 81-84. The detailed configuration of the downstream unit 3 will not be described here, as it is a known actuator.

[0036] (Brake ECU) The first brake ECU 901 and the second brake ECU 902 (hereinafter also referred to as "brake ECUs 901, 902") are electronic control units each equipped with a CPU and a memory. Each of the brake ECUs 901, 902 is equipped with one or more processors that execute various controls. The first brake ECU 901 and the second brake ECU 902 are separate ECUs, and are connected to each other so that they can communicate information (control information, etc.).

[0037] The first brake ECU 901 is configured to be able to control the upstream unit 11. In detail, the first brake ECU 901 is able to control the electric cylinder 2 and each of the solenoid valves 61, 62, 44, 40 based on data detected by a plurality of sensors 71, 72, 73 of the upstream unit. The first brake ECU 901 is able to calculate each wheel pressure based on the detection results of the pressure sensors 72, 73 and the control state of the downstream unit 3.

[0038] The second brake ECU 902 is configured to be able to control the downstream unit 3 based on data detected by the stroke sensor 71 and an internal pressure sensor (not shown). The second brake ECU 902 also receives data detected by a wheel speed sensor (not shown) and an acceleration sensor (not shown) provided on the vehicle. The second brake ECU 902 can control (pressure increase control, pressure decrease control, and pressure holding control) the downstream unit 3 to adjust the hydraulic pressure of each wheel cylinder 81-84. The second brake ECU 902 is configured to be able to execute anti-skid control (ABS control), anti-skid control, etc.

[0039] The vehicle braking system 1 is configured to be able to execute normal control. The normal control is also called a by-wire mode. In the normal control, the output pressure of the upstream unit 11 is the hydraulic pressure output by the electric cylinder 2. The downstream unit 3 is able to output hydraulic pressure to the wheel cylinders 81 to 84 based on the output pressure of the upstream unit 11. The normal control will be described below.

[0040] (Normal control) The normal control is a control in which the master cylinder device 4 and the wheel cylinders 81 to 84 are hydraulically isolated from each other, and the wheel cylinders 81 to 84 are pressurized by at least one of the electric cylinder 2 and the downstream unit 3. The normal control includes a preparatory control and a normal pressurization control.

[0041] The preparatory control is a control for establishing a so-called by-wire mode. In the preparatory control, the control unit 91 closes the master cut valve 62 and opens the system shutoff valve 61 and the simulator cut valve 44. The preparatory control is executed when the vehicle equipped with the vehicle braking device 1 is ready to start. Examples of when the vehicle is ready to start include when the ignition of the vehicle is turned on or when the electric vehicle is started.

[0042] The normal pressurization control is a control for pressurizing the wheel cylinders 81 to 84 in the by-wire mode (preparation control completed state). In the normal pressurization control, the first brake ECU 901 sets a target output pressure based on data detected by the stroke sensor 71 and the pressure sensor 72. The electric cylinder 2 is controlled based on the set target output pressure. The second brake ECU 902 activates the downstream unit 3 when performing anti-skid control or the like. In this way, in the normal control, the electric cylinder 2, the first hydraulic pressure output unit 31, and the second hydraulic pressure output unit 32 are controlled based on the set target value, thereby making it possible to adjust the hydraulic pressure of the wheel cylinders 81 to 84.

[0043] (refresh control) The fluid path 500 connecting the electric cylinder 2 and the stroke simulator 43 is made up of the portion of the second fluid path 52 that connects the electric cylinder 2 and the communication path 53, the communication path 53, the portion of the first fluid path 51 that connects the connection part 50 and the fluid path 43a, and the fluid path 43a (see the thick line in FIG. 1). In addition, as one of the fluid paths that connect to the master cylinder 41, the fluid path 40b is a fluid path that connects the master cylinder 41 to the portion of the fluid path 500 between the simulator cut valve 44 and the master cut valve 62.

[0044] The electric cylinder 2 is connected to a stroke simulator 43 via a hydraulic line 500, and is configured to be able to increase or decrease the pressure in the hydraulic line 500 without the driver's operation. The master cylinder 41 is connected to a reservoir 45 via a reservoir hydraulic line 40a, and is connected to the hydraulic line 500 via a portion 40b of a first hydraulic line 51.

[0045] The first brake ECU 901 includes a control unit 91 that executes refresh control at a predetermined timing (for example, during an initial check) to remove foreign matter that has entered the solenoid valve. The refresh control is a control that, with the target solenoid valve that is the target of the refresh control open, causes the electric cylinder 2 to execute a pressurizing process that pressurizes the stroke simulator 43 and the fluid path 500, and then executes a depressurizing process that depressurizes the fluid path 500, causing the fluid to flow from the stroke simulator 43 toward the simulator cut valve 44.

[0046] (First refresh control) As an example, the solenoid valve that is the target of the refresh control is a simulator cut valve that, when closed, prohibits the flow of fluid to the stroke simulator 43 via the fluid path 500. First, the refresh control for the simulator cut valve 44 will be described as "first refresh control."

[0047] The first refresh control is a control in which the above-mentioned pressurization control and depressurization control are performed while keeping the simulator cut valve (corresponding to the "target solenoid valve") 44 open, and causes the fluid in the stroke simulator 43 to flow toward the simulator cut valve 44.

[0048] More specifically, as shown in FIG. 2, in the pressurization process, the control unit 91 operates the electric cylinder 2 to pressurize the fluid path 500 while opening the simulator cut valve 44, the master cut valve, and the system shut-off valve 61 and closing the reservoir cut valve 40 (S101).

[0049] Next, the control unit 91 executes a first pressure reduction process in which the electric cylinder 2 reduces the pressure in a portion of the hydraulic path 500 closer to the electric cylinder 2 than the master cut valve 62, with the simulator cut valve 44 and the system shutoff valve 61 open and the master cut valve 62 and the reservoir cut valve 40 closed (S102). After executing the first pressure reduction process, the control unit 91 executes a second pressure reduction process in which the master cut valve 62 and the reservoir cut valve 40 are opened (S102). In this way, the pressure reduction process includes a first pressure reduction process and a second pressure reduction process.

[0050] In the pressurizing process, the electric cylinder 2 is controlled so that the output pressure of the electric cylinder 2 is higher than the normal operating range for normal braking (a hydraulic pressure range used except for emergency braking). In the pressurizing process, the control unit 91 advances the piston 23 so that the piston 23 bottoms out, for example. In this case, the electric cylinder 2 may be controlled based on a target value that is set in advance as the pressure required for the piston 23 to bottom out. Furthermore, when the first depressurizing process is completed, the piston 23 is returned to its initial position, and the hydraulic chamber 24 and the reservoir 45 are connected to each other.

[0051] The first pressure reduction process generates a pressure difference between the ports of the master cut valve 62 and between the ports of the reservoir cut valve 40. In other words, the fluid passage upstream of the master cut valve 62 becomes higher pressure than the fluid passage downstream of the master cut valve 62, and the fluid passage on the master cylinder 41 side of the reservoir cut valve 40 becomes higher pressure than the fluid passage on the reservoir 45 side of the reservoir cut valve 40.

[0052] When the second pressure-reducing process is performed after the first pressure-reducing process is completed, the fluid flows forcefully from the high-pressure fluid path to the low-pressure fluid path due to the pressure difference and the biasing force of the biasing member 433. Specifically, the fluid flows from the stroke simulator 43 into the electric cylinder 2 via the fluid path 500 including the simulator cut valve 44, and also flows from the stroke simulator 43 into the reservoir 45 via the simulator cut valve 44, the master cylinder 41, and the reservoir cut valve 40. In other words, due to the second pressure-reducing process, the fluid flows into the reservoir 45 via the master cylinder 41, and also flows into the electric cylinder 2 via the fluid path 500.

[0053] (Effect of the first refresh control) According to the first refresh control, the fluid in the stroke simulator 43 is pushed out into the fluid path 500 and flows away from the stroke simulator 43 via the simulator cut valve 44. The fluid in the fluid path 500 flows away from the stroke simulator 43 due to the pressure difference, and is also subjected to a pressing force from the piston 432. This increases the flow rate (flow velocity) of the fluid flowing from the stroke simulator 43 toward the simulator cut valve 44. Therefore, foreign matter in the simulator cut valve 44 is more easily removed from the simulator cut valve 44 by the fluid gaining momentum. According to this embodiment, the foreign matter removal performance for removing foreign matter in the solenoid valve can be improved.

[0054] Furthermore, in the pressurization process, a higher hydraulic pressure than the normal range is generated in the hydraulic passage 500, so that fluid flows with more force than usual from the electric cylinder 2 to the stroke simulator 43 via the simulator cut valve 44. In the pressurization process, a flow occurs in the opposite direction to the fluid flow caused by the depressurization process, making it easier to remove foreign matter on the other side of the simulator cut valve 44. The pressurization process makes it easier to remove foreign matter on one side of the solenoid valve, and the depressurization process makes it easier to remove foreign matter on the other side of the solenoid valve.

[0055] In this embodiment, the pressure reduction process includes a first pressure reduction process and a second pressure reduction process. This allows a pressure difference to be created in the fluid path 500 across the master cut valve 62, and opening the master cut valve 62 allows the fluid to flow forcefully. In this embodiment, the reservoir cut valve 40 is also opened during the second pressure reduction process, so the fluid flows toward the two outlets of the master cut valve 62 and the reservoir cut valve 40. This further increases the flow rate of the fluid.

[0056] (First Modification of First Refresh Control) Modifications of the first refresh control will be described using a first modification and a second modification. In the modification, the pressure reduction process is not divided into the first and second pressure reduction processes as described above, but is completed as a single process. In the first modification, as shown in FIG. 3, the control unit 91 first operates the electric cylinder 2 in the pressurization process while opening the simulator cut valve 44, the master cut valve, and the system shutoff valve 61 and closing the reservoir cut valve 40, as in the above control example (S201). This pressurizes the hydraulic passage 500, the stroke simulator 43, and the master chamber 41a.

[0057] Next, in the pressure reduction process, the control unit 91 opens the reservoir cut valve 40 while maintaining the simulator cut valve 44, the master cut valve, and the system shutoff valve 61 in an open state (S202). Also, in the pressure reduction process, the control unit 91 stops the operation of the electric cylinder 2 or reverses the rotation of the electric motor 22, thereby moving the piston 23 of the electric cylinder 2 toward the initial position.

[0058] According to the first modification of the first refresh control, the reservoir cut valve 40 opens during the pressure reduction process, and the fluid path 500 communicates with the reservoir 45 via the master cylinder 41. As a result, the fluid pushed out at high pressure by the piston 432 of the stroke simulator 43 flows into the reservoir 45 via the simulator cut valve 44 and the master cylinder 41. The fluid flows through the simulator cut valve 44 with great force. As a result, any foreign matter in the simulator cut valve 44 is removed.

[0059] (Second Modification of First Refresh Control) 3, in the second modified example, first, in the pressurization process, the control unit 91 operates the electric cylinder 2 in a state where the simulator cut valve 44, the master cut valve, and the system shutoff valve 61 are opened and the reservoir cut valve 40 is closed (S201), as in the above control example. As a result, the hydraulic passage 500, the stroke simulator 43, and the master chamber 41a are pressurized.

[0060] Next, in the pressure reduction process, the control unit 91 stops the operation of the electric cylinder 2 or reverses the rotation of the electric motor 22 while maintaining the simulator cut valve 44, master cut valve, and system shut-off valve 61 in an open state and the reservoir cut valve 40 in a closed state, thereby moving the piston 23 of the electric cylinder 2 toward its initial position.

[0061] According to the second modification of the first refresh control, the electric cylinder 2 depressurizes the fluid path while maintaining the open / closed state of the solenoid valve during the pressurization process. Because the solenoid valve does not open or close, power consumption can be reduced more than in the first modification. As the electric cylinder 2 moves toward the initial position, fluid flows through the simulator cut valve 44. This removes foreign matter from the simulator cut valve 44.

[0062] (Second refresh control) The target solenoid valve of the second refresh control is the master cut valve 62, which, when closed, prohibits the flow of fluid between the stroke simulator 43, the master cylinder 41, and the electric cylinder 2. The simulator cut valve 44 is disposed in a portion of the fluid passage 500 between the target solenoid valve (master cut valve 62) and the stroke simulator 43. In the second refresh control, a pressurization process, a first pressure reduction process, and a second pressure reduction process are executed (see FIG. 2).

[0063] The pressurization process of the second refresh control is the same as the pressurization process of the first refresh control. In the first depressurization process, the simulator cut valve 44 and the master cut valve 62 are opened and the system shutoff valve 61 and the reservoir cut valve 40 are closed, and the electric cylinder 2 depressurizes the portion of the hydraulic path 500 on the electric cylinder 2 side relative to the system shutoff valve 61. In the second depressurization process, the simulator cut valve 44 and the master cut valve 62 are opened and the reservoir cut valve 40 is closed, and the system shutoff valve 61 is opened.

[0064] By the second refresh control, the fluid pushed out at high pressure by the piston 432 of the stroke simulator 43 flows vigorously through the fluid path 500 and into the electric cylinder 2 via the master cut valve 62. This improves the foreign matter removal performance inside the master cut valve 62.

[0065] (Third refresh control) The solenoid valve that is the target of the third refresh control is the system shutoff valve 61, which is disposed between the master cut valve 62 and the electric cylinder 2 and switches between communication and cutoff between the electric cylinder 2 and the wheel cylinders 81 and 82 (corresponding to the "second wheel cylinder") while allowing communication between the electric cylinder 2 and the wheel cylinders 83 and 84 (corresponding to the "first wheel cylinder"). The third refresh control includes a pressurization process and a depressurization process (see FIG. 3).

[0066] In the pressurizing process, the control unit 91 opens the simulator cut valve 44, the master cut valve 62, and the system shutoff valve 61 and closes the reservoir cut valve 40, and causes the electric cylinder 2 to pressurize the stroke simulator 43 and the hydraulic path 500. Subsequently, in the depressurizing process, the control unit 91 opens the simulator cut valve 44, the master cut valve 62, and the system shutoff valve 61 and closes the reservoir cut valve 40, and causes the electric cylinder 2 to depressurize the hydraulic path 500. In the depressurizing process, the control unit 91 (forcibly) moves the piston 23 toward the initial position by, for example, using the driving force of the electric motor 22.

[0067] According to the third refresh control, the fluid pushed out at high pressure by the piston 432 of the stroke simulator 43 due to the depressurization process after the pressurization process flows vigorously through the fluid path 500 and into the electric cylinder 2 via the system shutoff valve 61. This improves the foreign matter removal performance inside the system shutoff valve 61.

[0068] (others) The present invention is not limited to the above embodiment. For example, if the reservoir cut valve 40 is not provided in the reservoir fluid path 40a, the connection to the reservoir 45 via the master cylinder 41 may be blocked by other means. The pressure-increasing / depressurizing device capable of inflating / depressurizing the fluid path 500 is not limited to the electric cylinder 2, but may also be the downstream unit 3. For example, the downstream unit 3, such as an ESC actuator, can inflat / depressurize the fluid path connecting the downstream unit 3 and the stroke simulator 43, just like the electric cylinder 2. In this case, the control unit 91 executes refresh control in cooperation with the second brake ECU 902. The master cut valve 62 may also be configured with two solenoid valves connected in parallel. The electric cylinder 2 may not have the biasing member 25.

[0069] <Configuration common to the above four refresh controls: Basic configuration> The vehicle braking system 1 includes a stroke simulator 43, a pressure increasing / depressurizing device (electric cylinder 2 or downstream unit 3), a target solenoid valve (simulator cut valve 44, master cut valve 62, or system shutoff valve 61) that is a solenoid valve provided in a hydraulic passage 500, and a control unit 91. The stroke simulator 43 includes a cylinder 431 and a piston 432 that is biased toward an initial position by a biasing member 433 provided inside the cylinder 431, and is configured so that when fluid is supplied from a hydraulic passage 500 connected to the cylinder 431, the piston 432 moves away from the initial position against the biasing force of the biasing member 433. The pressure increasing / depressurizing device is connected to the stroke simulator 43 via the hydraulic passage 500 across a target solenoid valve that is a solenoid valve provided in the hydraulic passage 500, and is configured to increase or decrease the pressure in the hydraulic passage 500 without the driver's operation by supplying fluid to or discharging fluid from the hydraulic passage 500. The control unit 91 executes refresh control, in which the pressurizing / depressurizing device executes a pressurizing process to pressurize the stroke simulator 43 and the fluid path 500 while the target solenoid valve is open, and then executes a depressurizing process to depressurize the fluid path 500, thereby causing the fluid to flow from the stroke simulator 43 toward the target solenoid valve. The depressurizing process may be a one-stage depressurizing process (a modified example of the first refresh control and the third refresh control) or a multi-stage depressurizing process (the first and second refresh controls).

[0070] <Configuration common to the first refresh control and the second refresh control: First configuration> In addition to the basic configuration, the vehicle braking system 1 further includes a cutoff valve (master cutoff valve 62 or system cutoff valve 61), which is a solenoid valve arranged in a portion between the target solenoid valve (simulator cutoff valve 44 or master cutoff valve 62) and the pressurizing / pressurizing device in the hydraulic passage 500. In the pressure reducing process of the basic configuration, the control unit 91 executes a first pressure reducing process in which the pressurizing / pressurizing device reduces the pressure in the portion of the hydraulic passage 500 closer to the pressurizing / pressurizing device than the cutoff valve, with the target solenoid valve opened and the cutoff valve closed, and then executes a second pressure reducing process in which the cutoff valve is opened.

[0071] <Configuration of first refresh control> In addition to the first configuration, the vehicle braking device 1 further includes a reservoir fluid path 40a connecting the master cylinder 41 and the reservoir 45, a reservoir cut valve 40 which is an electromagnetic valve provided in the reservoir fluid path 40a, and a fluid path 40b connecting the master cylinder 41 to the portion of the fluid path 500 between the simulator cut valve 44 (target solenoid valve) and the master cut valve 62 (shut-off valve).

[0072] The target solenoid valve is the simulator cut valve 44, which, when closed, prohibits the flow of fluid to the stroke simulator 43. The control unit 91 closes the reservoir cut valve 40 in the pressurization process and the first depressurization process of the first configuration, and opens the reservoir cut valve 40 in the second depressurization process of the first configuration.

[0073] <Configuration of Modified Example of First Refresh Control> In addition to the basic configuration, the vehicle braking system 1 further includes a reservoir fluid path 40a and a reservoir cut valve 40. The target solenoid valve is a simulator cut valve 44. The control unit 91 closes the reservoir cut valve 40 during the pressurization process of the basic configuration, and opens the reservoir cut valve 40 during the depressurization process of the basic configuration. The pressure reduction (depressurization process) of the fluid path 500 is performed by opening the reservoir cut valve 40.

[0074] <Configuration of second refresh control> In the first configuration, the vehicle braking system 1 includes a simulator cut valve 44, which is a solenoid valve arranged in a portion of the fluid passage 500 between a master cut valve 62 (target solenoid valve) and the stroke simulator 43. The target solenoid valve is the master cut valve 62, which, when closed, prohibits the flow of fluid between the stroke simulator 43 and the pressure-compressing device (the electric cylinder 2 or the downstream unit 3).

[0075] In the pressurization process of the first configuration, the control unit 91 pressurizes the stroke simulator 43 and the hydraulic passage 500 using the pressurization / depressurization device with the simulator cut valve 44, the master cut valve 62, and the system shutoff valve 61 (shutoff valve) open. In the second depressurization process, the control unit 91 opens the system shutoff valve 61 with the simulator cut valve 44 and the master cut valve 62 open.

[0076] <Third refresh control> The target solenoid valve is the system shutoff valve 61, and the vehicle braking system 1 further includes, in addition to the basic configuration, a simulator cut valve 44 and a master cut valve 62. The control unit 91 executes a pressurization process with the simulator cut valve 44, the master cut valve 62, and the system shutoff valve 61 open, and executes a depressurization process by depressurizing the hydraulic passage 500 using the electric cylinder 2 (pressurization / depressurization device) with the simulator cut valve 44, the master cut valve 62, and the system shutoff valve 61 open.

[0077] <Another description of refresh control> The vehicle braking system includes a shutoff valve, which is a solenoid valve, located between the target solenoid valve and the pressurizing / depressurizing device in the hydraulic line 500. In the pressurizing process, the control unit 91 pressurizes the stroke simulator 43 and the hydraulic line 500 using the pressurizing / depressurizing device while maintaining the shutoff valve and the target solenoid valve open, and in the depressurizing process, depressurizes the hydraulic line 500 using the pressurizing / depressurizing device while keeping the shutoff valve and the target solenoid valve open, which were open in the pressurizing process. The vehicle braking system also includes a reservoir cut valve 40, which is a solenoid valve provided in a reservoir fluid passage 40a that connects the master cylinder 41 and a reservoir 45. The target solenoid valve is a simulator cut valve 44 that, when closed, prohibits the flow of fluid to the stroke simulator 43 via a fluid passage 500. In a pressurization process, the control unit 91 pressurizes the stroke simulator 43 and the fluid passage 500 using a pressurization / depressurization device while keeping the shutoff valve and the target solenoid valve open and the reservoir cut valve 40 closed, and in a depressurization process, opens the reservoir cut valve 40 while keeping the shutoff valve and the target solenoid valve that were open in the pressurization process, thereby depressurizing the fluid passage 500 using the pressurization / depressurization device. [Explanation of symbols]

[0078] 1...vehicle braking system, 2...electric cylinder (pressurizing / depressurizing device), 3...downstream unit (pressurizing / depressurizing device), 40...reservoir cut valve, 40a...reservoir fluid path, 40b...fluid path, 41...master cylinder, 43...stroke simulator, 431...cylinder, 432...piston, 433...biasing member, 44...simulator cut valve (target solenoid valve), 45...reservoir, 500...fluid path, 61...system shut-off valve (target solenoid valve, shut-off valve), 62...master cut valve (target solenoid valve, shut-off valve), 81, 82...wheel cylinder (second wheel cylinder), 83, 84...wheel cylinder (first wheel cylinder), 91...control unit.

Claims

1. a stroke simulator including a cylinder and a piston biased toward an initial position by a biasing member provided inside the cylinder, wherein the piston moves away from the initial position against the biasing force of the biasing member when fluid is supplied from a fluid passage connected to the cylinder; a pressure increasing / depressurizing device that is connected to the stroke simulator via the fluid path across a target solenoid valve that is a solenoid valve provided in the fluid path, and is configured to be able to increase or decrease the pressure of the fluid path without the operation of a driver by supplying fluid to the fluid path or discharging fluid from the fluid path; a control unit that executes refresh control for causing the fluid to flow from the stroke simulator toward the target solenoid valve by causing the pressurizing / depressurizing device to execute a pressurizing process for pressurizing the stroke simulator and the fluid path while the target solenoid valve is open, and then executing a depressurizing process for depressurizing the fluid path; A vehicle braking device comprising:

2. a shutoff valve that is an electromagnetic valve disposed in a portion of the fluid path between the target electromagnetic valve and the pressure increasing / decreasing device, The control unit, in the pressure reduction process, executes a first pressure reduction process in which the pressure is reduced in a portion of the fluid path on the pressure reduction device side relative to the shutoff valve by the pressure reduction device with the target solenoid valve opened and the shutoff valve closed, and then executes a second pressure reduction process in which the shutoff valve is opened.

2. A vehicle brake system according to claim 1.

3. The master cylinder is connected to the reservoir by a reservoir cut valve, which is an electromagnetic valve provided in the reservoir fluid passage that connects the master cylinder to the reservoir. the target solenoid valve is a simulator cut valve that, when closed, prohibits the flow of fluid to the stroke simulator through the fluid path, the control unit closes the reservoir cut valve in the pressurizing process and the first depressurizing process, and opens the reservoir cut valve in the second depressurizing process.

3. A vehicle brake system according to claim 2.

4. a shutoff valve that is an electromagnetic valve disposed in a portion of the fluid path between the target electromagnetic valve and the pressure increasing / decreasing device, The control unit is In the pressurizing process, the stroke simulator and the hydraulic passage are pressurized by the pressurizing / depressurizing device while maintaining the shutoff valve and the target solenoid valve in an open state; In the depressurization process, the pressure in the liquid path is reduced by the pressurization / depressurization device while the shutoff valve and the target solenoid valve that were opened in the pressurization process are kept open.

2. A vehicle brake system according to claim 1.

5. The master cylinder is connected to the reservoir by a reservoir cut valve, which is an electromagnetic valve provided in the reservoir fluid passage that connects the master cylinder to the reservoir. the target solenoid valve is a simulator cut valve that, when closed, prohibits the flow of fluid to the stroke simulator through the fluid path, The control unit is In the pressurizing process, the stroke simulator and the hydraulic passage are pressurized by the pressurizing / depressurizing device while maintaining a state in which the shutoff valve and the target solenoid valve are opened and the reservoir cut valve is closed; In the depressurization process, the reservoir cut valve is opened while the shutoff valve and the target solenoid valve that were opened in the pressurization process are kept open, and the pressure in the fluid path is reduced by the pressurization / depressurization device.

5. A vehicle braking system according to claim 4.

6. The master cylinder is connected to the reservoir by a reservoir cut valve, which is an electromagnetic valve provided in the reservoir fluid passage that connects the master cylinder to the reservoir. the target solenoid valve is a simulator cut valve that, when closed, prohibits the flow of fluid to the stroke simulator through the fluid path, The control unit closes the reservoir cut valve in the pressurizing process and opens the reservoir cut valve in the depressurizing process.

2. A vehicle brake system according to claim 1.

7. a simulator cut valve which is a solenoid valve arranged in a portion of the fluid path between the target solenoid valve and the stroke simulator; a master cut valve which is a solenoid valve arranged in a portion of the fluid path between the target solenoid valve and the simulator cut valve; Further equipped with the target solenoid valve is a system cutoff valve that is disposed between the master cut valve and the pressure increasing / reducing device and switches between communication and cutoff between the pressure increasing / reducing device and a second wheel cylinder while allowing communication between the pressure increasing / reducing device and a first wheel cylinder, the control unit executes the pressurizing process in a state in which the simulator cut valve, the master cut valve, and the system shutoff valve are opened, and executes the depressurizing process of depressurizing the fluid path by the pressurizing / depressurizing device in a state in which the simulator cut valve, the master cut valve, and the system shutoff valve are opened.

2. A vehicle brake system according to claim 1.

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