Brake fluid pressure control device for vehicle

Abstract

To provide a vehicle brake fluid pressure control device capable of improving a brake feeling when a brake operator is operated with pressurization control of brake fluid in execution.SOLUTION: A vehicle brake fluid pressure control device comprises a fluid pressure circuit which is arranged between a master cylinder M which generates a fluid pressure of work fluid in accordance with an operation amount of a brake operator and a wheel brake W which is operated with the supplied fluid pressure of the work fluid. The wheel brake W has first wheel cylinders W1 and W1 and a second wheel cylinder W2. The fluid pressure circuit has: a main fluid pressure circuit HP1 from the master cylinder M to the first wheel cylinders W1 and W1; a normally opened solenoid valve and a normally closed solenoid valve which are installed in the main fluid pressure circuit HP1; and a pressurized fluid pressure circuit HP2 which is branched from a position between the normally closed solenoid valve and the first wheel cylinders W1 and W1 in the main fluid pressure circuit HP1 and leads to the second wheel cylinder W2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a brake fluid pressure control device for a vehicle, and more particularly to a brake fluid pressure control device for a vehicle that can be mounted on a bar handle type vehicle such as a motorcycle, a motorcycle, or an all-terrain vehicle (ATV). [Background technology]

[0002] Patent Document 1 discloses a technology for a brake control system for a motorcycle, in which a single hydraulic circuit is provided with a pump for antilock brake control and a pressure pump for controlling the pressure of the hydraulic fluid. The brake control system of Patent Document 1 is equipped with a stroke simulator that allows brake fluid to flow in, in order to ensure a good operational feeling when the brake operator is operated during hydraulic fluid pressure control. The stroke simulator is provided in the flow path from the master cylinder to the pressure pump, and is configured to stroke in response to the hydraulic fluid pressure generated by operating the brake operator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6045816 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, the brake control system of Patent Document 1 ensures an operational feeling when controlling the hydraulic fluid pressure by flowing brake fluid into a stroke simulator. However, because the actual operation amount of the brake operator differs from the hydraulic fluid pressure acting on the wheel cylinder, the operation amount of the brake operator does not match the vehicle deceleration, which can cause a sense of discomfort to the driver.

[0005] The present invention aims to solve the above-mentioned problems and provide a brake fluid pressure control device for a vehicle that can improve the braking feeling when a brake operator is operated during hydraulic fluid pressure control. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a vehicle brake fluid pressure control device that includes a hydraulic circuit disposed between a master cylinder that generates hydraulic fluid pressure in response to the amount of operation of a brake operator, and a wheel brake that is operated by the hydraulic pressure of the supplied hydraulic fluid. The wheel brake has a first wheel cylinder and a second wheel cylinder, and the hydraulic circuit includes a main hydraulic circuit that extends from the master cylinder to the first wheel cylinder, a normally open solenoid valve and a normally closed solenoid valve provided in the main hydraulic circuit, and a pressurized hydraulic circuit that branches off from the main hydraulic circuit between the normally open solenoid valve and the first wheel cylinder and extends to the second wheel cylinder. are . The pressurization hydraulic circuit is provided with a pressurization pump, which has an intake valve with an opening pressure lower than atmospheric pressure and is self-suctioning. The pressurization hydraulic circuit is provided with a pressurization reservoir between a branch point with the main hydraulic circuit and the intake side of the pressurization pump. The pressurization reservoir initially stores hydraulic fluid.

[0007] In this invention, hydraulic fluid pressure generated in the master cylinder acts on the first wheel cylinder through a main hydraulic circuit. Meanwhile, hydraulic fluid pressure generated in the master cylinder acts on the second wheel cylinder through a pressurized hydraulic circuit branching off from the main hydraulic circuit. In other words, hydraulic fluid pressure acts on the first wheel cylinder and the second wheel cylinder through different paths. As a result, for example, if hydraulic fluid pressure is acting on the second wheel cylinder through the pressurized hydraulic circuit due to hydraulic fluid pressure control, and a brake operator is additionally operated, hydraulic fluid pressure generated in the master cylinder due to operation of the brake operator acts on the first wheel cylinder through the main hydraulic circuit. In other words, in addition to the hydraulic fluid pressure acting on the wheel brakes due to pressurization control, hydraulic fluid pressure equivalent to the amount of brake fluid pressure generated by operating the brake operator is applied to the wheel brakes. Therefore, the amount of brake operator operation matches the vehicle deceleration, providing a good braking feel. Furthermore, for example, if the brake operator is operated and hydraulic fluid pressure control is additionally performed, hydraulic fluid is drawn from the master cylinder by the pressurized hydraulic circuit, and hydraulic fluid pressure is applied to the second wheel cylinder through the pressurized hydraulic circuit. This causes the brake operator to move further in the operating direction. Therefore, the amount of brake operation matches the vehicle deceleration, providing a good braking feel.

[0009] Also, There is no need to provide a suction control valve in the pressurized hydraulic circuit, and the number of control valves in the hydraulic circuit can be minimized, thereby reducing costs.

[0011] Also, For example, when the hydraulic fluid pressure is automatically increased, the hydraulic fluid is drawn from the pressurization reservoir, which allows for a shorter flow path than when drawing from the master cylinder. Furthermore, when the brake operator is operated during automatic hydraulic fluid pressure increase control, the hydraulic fluid from the master cylinder acts on the first wheel cylinder and also flows into the pressurization reservoir, which prevents the input from the brake lever from becoming too stiff and matches the amount of brake operator operation with the vehicle deceleration, providing a good braking feel.

[0012] It is also preferable that the pressurized hydraulic circuit is provided with a pressure regulating valve capable of controlling the valve opening pressure.

[0013] In this configuration, the brake fluid in the pressurized hydraulic circuit can be returned through the pressure regulating valve, making it possible to regulate the pressure in the pressurized hydraulic circuit.

[0014] The pressurizing reservoir preferably includes a diaphragm and a plug on which the diaphragm is seated, and the diaphragm divides the reservoir into a liquid storage chamber and an atmospheric chamber. In this case, the plug preferably includes a communication passage communicating with the atmosphere.

[0015] In this configuration, the pressurizing reservoir can be configured with a simple structure that utilizes the elastic deformation of the diaphragm, thereby reducing the number of parts and costs.

[0016] Preferably, the first wheel cylinder and the second wheel cylinder are provided in a single caliper body.

[0017] This configuration reduces the number of parts and costs compared to a double-disc wheel brake. [Effects of the Invention]

[0018] According to the vehicle brake fluid pressure control device of the present invention, it is possible to improve the braking feeling when the brake operator is operated during the control of the hydraulic fluid pressure increase. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a hydraulic circuit diagram acting on a front wheel brake that is applied to a vehicle brake hydraulic pressure control device according to an embodiment of the present invention; [Figure 2] 1A and 1B are diagrams showing a pressurizing reservoir provided in a vehicle brake fluid pressure control device according to an embodiment of the present invention, in which (a) is a cross-sectional view showing a state in which brake fluid is stored in a fluid storage chamber, and (b) is a cross-sectional view showing a state in which brake fluid has been sucked from the fluid storage chamber. [Figure 3A] 1 is a hydraulic circuit diagram showing the flow of brake fluid when the front wheel brake pressure is increased in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention; [Figure 3B] 1 is a hydraulic circuit diagram showing the flow of brake fluid when the pressure in a front wheel brake is reduced in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention; [Figure 3C] 1 is a hydraulic circuit diagram showing the flow of brake fluid related to pressure reduction control during antilock brake control in a front wheel brake in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 3D] 1 is a hydraulic circuit diagram showing the flow of brake fluid related to pressure increase control during antilock brake control in front wheel brakes in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention; [Figure 3E] 1 is a hydraulic circuit diagram showing the flow of brake fluid related to holding control during antilock brake control in front wheel brakes in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention; [Figure 4A] 1 is a hydraulic circuit diagram showing the flow of brake fluid when the front wheel brakes, which operate in conjunction with the sole operation of the rear wheel brake operator, are pressurized in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 4B] 1 is a hydraulic circuit diagram showing the flow of brake fluid when the front wheel brakes, which operate in conjunction with the sole operation of the rear wheel brake operator, are depressurized in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. FIG. [Figure 4C] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid in the brake fluid pressure control device for a vehicle according to an embodiment of the present invention, during anti-lock brake control of the front wheel brakes, which operates in conjunction with the sole operation of the rear wheel brake operator. [Figure 5A] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid during pressure buildup in the front wheel brakes when the rear wheel brake operator is operated after the front wheel brake operator in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 5B] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid during pressure reduction in the front wheel brakes in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention, when the front wheel brake operator is operated, followed by the rear wheel brake operator, and then the front wheel brake operator is released. [Figure 5C] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid in relation to pressure reduction control during antilock brake control when a rear wheel brake operator is operated after a front wheel brake operator in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 5D] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid related to pressure increase control during antilock brake control when a rear wheel brake operator is operated after a front wheel brake operator in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 6A] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid during pressure buildup in the front wheel brakes when the front wheel brake operator is operated after the rear wheel brake operator in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention. [Figure 6B] FIG. 1 is a hydraulic circuit diagram showing the flow of brake fluid during pressure reduction in the front wheel brakes in a vehicle brake hydraulic pressure control device according to an embodiment of the present invention, when the rear wheel brake operator is operated, followed by the front wheel brake operator, and then the rear wheel brake operator is released. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same elements are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0021] As shown in FIG. 1, a vehicle brake fluid pressure control device (hereinafter referred to as "brake control device") 1 of this embodiment is suitable for use in bar handle type vehicles such as motorcycles, motor tricycles, and all-terrain vehicles (ATVs). In a vehicle equipped with the brake control device 1, it is preferable that the front wheel brake unit and the rear wheel brake unit are separate. In this embodiment, a brake control device 1 including a brake system K connected to a front wheel brake W will be described.

[0022] The brake control device 1 adjusts the brake fluid pressure, which is the hydraulic pressure of the hydraulic fluid acting on the front wheel brakes W, and is capable of performing antilock brake non-control, antilock brake control, pressurization control, and interlock brake control, which increase or decrease the brake fluid pressure acting on the wheel brakes W. Note that, in the following, "pressurization control" will be described using as an example "automatic pressurization control" that is performed during interlock brake control. The wheel brake W has three wheel cylinders, consisting of a pair of first wheel cylinders W1, W1 and a second wheel cylinder W2. Each wheel cylinder W1, W1, W2 is integrally formed in one caliper body.

[0023] The hydraulic circuit of the brake control device 1 includes a main hydraulic circuit HP1 and a pressurized hydraulic circuit HP2 branched off from the main hydraulic circuit HP1. The main hydraulic circuit HP1 includes an inlet valve 2, an outlet valve 3, a reservoir 4, a pump 5, and a motor 6. On the other hand, the pressurized hydraulic circuit HP2 includes a pressurizing reservoir 11, a pressurizing pump 12, a regulator (pressure adjusting valve) 13, and a sensor 14. The rear wheel brake system (not shown) is similar to the front wheel brake system K except that it does not include the pressurized hydraulic circuit HP2.

[0024] Hereinafter, the hydraulic path connected to the master cylinder M and extending from the master cylinder M to the inlet valve 2 will be referred to as the "output hydraulic path A," and the path from the inlet valve 2 to the outlet valve 3 and outlet port 22 (first wheel cylinder W1, W1) will be referred to as the "wheel hydraulic path B." The path from the outlet valve 3 to the reservoir 4 and pump 5 will be referred to as the "open path C." The path from the pump 5 to the output hydraulic path A will be referred to as the "discharge hydraulic path D." The path branching from the wheel hydraulic path B to the pressurized hydraulic circuit HP2 and extending to the pressurized reservoir 11 and pressurizing pump 12 will be referred to as the "branch hydraulic path E." The path from the pressurizing pump 12 to the pressurized outlet port 23 (second wheel cylinder W2) will be referred to as the "pressurized hydraulic path F." The path connecting the branch hydraulic path E and the pressurized hydraulic path F via the regulator 13 will be referred to as the "communicating hydraulic path G." It should be noted that "upstream side" refers to the master cylinder M side, and "downstream side" refers to the wheel brake W side.

[0025] The main hydraulic circuit HP1 of the brake control device 1 is a circuit that extends from an inlet port 21 to an outlet port 22. A pipe H1 that leads to a master cylinder M, which is a hydraulic pressure source, is connected to the inlet port 21, and a pipe H2 that leads to first wheel cylinders W1, W1 of the wheel brake W is connected to the outlet port 22.

[0026] A brake operator (brake lever) L1 is connected to the master cylinder M. The master cylinder M generates brake fluid pressure according to the force applied to the brake operator L1 by the driver. The master cylinder M is connected to first wheel cylinders W1, W1 of the wheel brakes W via a pipe H1, an output hydraulic pressure line A, a wheel hydraulic pressure line B, and a pipe H2. The fluid lines (output fluid pressure line A and wheel fluid pressure line B) connected to the master cylinder M communicate from the master cylinder M to the first wheel cylinders W1, W1 when the antilock brake is not being controlled. This allows the brake fluid pressure generated by operating the brake operator L1 to be transmitted to the first wheel cylinders W1, W1. An inlet valve 2 is provided on a fluid path connecting the master cylinder M and the first wheel cylinders W1, W1.

[0027] The inlet valve 2 is a normally open electromagnetic valve, such as a linear solenoid valve whose valve opening pressure can be controlled by an electric current. When the inlet valve 2 is in an open state, it allows brake fluid pressure from the master cylinder M to be transmitted to the first wheel cylinders W1, W1. When the wheels are about to lock, the inlet valve 2 is closed under the control of the control device 50, thereby cutting off the brake fluid pressure applied to the first wheel cylinders W1, W1.

[0028] A check valve 2a is connected in parallel to the inlet valve 2. The check valve 2a is a valve that only allows brake fluid (hydraulic fluid) to flow from the first wheel cylinders W1, W1 to the master cylinder M. When the input of the brake operator L1 is released, the check valve 2a allows brake fluid to flow from the first wheel cylinders W1, W1 to the master cylinder M even when the inlet valve 2 is closed. The check valve 2a is provided integrally with a normally open solenoid valve that constitutes the inlet valve 2.

[0029] The outlet valve 3 is a normally closed solenoid valve. The outlet valve 3 is located between the first wheel cylinders W1, W1 and the reservoir 4 (between the wheel hydraulic pressure path B and the open path C). The outlet valve 3 is closed when the antilock brake control is not in effect, but is opened by the control device 50 when the front wheels are about to lock, thereby releasing the brake hydraulic pressure acting on the first wheel cylinders W1, W1 and the brake hydraulic pressure acting on the second wheel cylinder W2 to the reservoir 4.

[0030] The reservoir 4 has a function of temporarily storing the brake fluid that is released when the outlet valve 3 is opened.

[0031] The pump 5 is driven by an electric motor 6. The pump 5 is disposed between the open passage C and the output hydraulic pressure passage A. The pump 5 is a plunger type pump. The pump 5 is equipped with an intake valve 5a and a discharge valve 5b whose valve opening pressure is higher than atmospheric pressure. The electric motor 6 also serves as a motor for driving the pressurizing pump 12.

[0032] The pump 5 sucks in the brake fluid temporarily stored in the reservoir 4 and discharges it to the output hydraulic pressure path A. In other words, the pump 5 has the function of returning the brake fluid on the reservoir 4 side (open path C side) to the master cylinder M side.

[0033] The pressurized hydraulic circuit HP2 is a circuit extending from the branch hydraulic line E in the wheel hydraulic line B and a branch point 24 to a pressurized outlet port 23. A pipe H3 leading to the second wheel cylinder W2 of the wheel brake W is connected to the pressurized outlet port 23.

[0034] The pressurizing reservoir 11 is provided midway along the branch hydraulic line E. The pressurizing reservoir 11 serves to supply brake fluid to the pressurizing pump 12. As shown in FIG. 2(a), the pressurizing reservoir 11 includes a diaphragm 110 and a plug 120 on which the diaphragm 110 is seated and which fixes the diaphragm 110. The pressurizing reservoir 11 is divided by the diaphragm 110 into a fluid storage chamber 11a and an atmospheric chamber 11b (see FIG. 2(b)). The pressurizing reservoir 11 is configured so that brake fluid is stored in the fluid storage chamber 11a in the initial state (a state in which brake control such as antilock brake control or interlock brake control is not being executed). The fluid storage chamber 11a is connected to a communication passage E1 that leads to the upstream side of the branch hydraulic line E and a communication passage E2 that leads to the downstream side of the branch hydraulic line E. The plug 120 has a communication hole 125 that communicates with the atmosphere side. The diaphragm 110 and the plug 120 are attached to a pressurizing reservoir attachment hole 101 of a base body 100 that constitutes the brake control device 1.

[0035] The diaphragm 110 includes an annular seal portion 111 that is in close contact with the inner circumferential surface of the pressurizing reservoir mounting hole 101, and a thin film portion 115 that is continuous with the seal portion 111 on the radially inner side. The seal portion 111 has an annular cup seal portion 112 extending on the opposite side to the opening of the pressurizing reservoir mounting hole 101. The seal portion 111 seals to prevent air from being sucked in from the outside due to the negative pressure generated when the pressurizing pump 12 is operated.

[0036] The thin film portion 115 is formed thinner than the seal portion 111, and includes a rising portion 116 that extends in an arc shape radially inward from the seal portion 111, and a flat portion 117 that is continuous with the radially inner side of the rising portion 116. When the liquid storage chamber 11a separated by the diaphragm 110 becomes negative pressure, the rising portion 116 elastically deforms and the flat portion 117 separates from the plug 120 (see FIG. 2(b)). An annular rib 118 is formed on the underside of the flat portion 117 to prevent the flat portion 117 from coming into close contact with the seating surface of the plug 120.

[0037] The plug 120 is a member that fixes the diaphragm 110 inside the pressurizing reservoir mounting hole 101 (inside the base 100), and is mounted on the inside of the opening of the pressurizing reservoir mounting hole 101. The plug 120 includes a base 121, a fitting portion 122, a retaining portion 123, a lip portion 124, and a communication hole 125.

[0038] The fitting portion 122 has a flange shape extending radially outward and is fitted to the inner circumferential surface of the pressurizing reservoir mounting hole 101. A retaining ring 126 is fitted to the fitting portion 122 to prevent it from coming off. The retaining portion 123 is formed by utilizing the flange surface of the fitting portion 122. The seal portion 111 of the diaphragm 110 is fitted onto the retaining portion 123. The lip portion 124 is continuous with the retaining portion 123 and bulges from the retaining portion 123 toward the inside of the fluid storage chamber 11a. The upper end of the lip portion 124 is arc-shaped. The lip portion 124 is located below the rising portion 116 of the diaphragm 110 and prevents the diaphragm 110 from deforming more than necessary when brake fluid pressure from the master cylinder M side acts on the fluid storage chamber 11a.

[0039] The pressurizing pump 12 is a pump driven by the electric motor 6, and is interposed between the branch hydraulic line E and the pressurized hydraulic line F. The pressurizing pump 12 is a suction-type plunger pump. The pressurizing pump 12 is equipped with an intake valve 12a and a discharge valve 12b whose valve opening pressure is lower than atmospheric pressure.

[0040] The pressurizing pump 12 draws in brake fluid stored in the pressurizing reservoir 11 and brake fluid on the master cylinder M side and discharges it into the pressurized hydraulic line F. This makes it possible to automatically apply brake fluid pressure to the second wheel cylinder W2 of the wheel brake W during interlocking brake control even when the front wheel brake operator L1 is not being operated (by operating the rear wheel brake operator). The rear wheel brake operator is a brake lever or a brake pedal.

[0041] Regulator 13 is a normally-open linear solenoid valve disposed in communicating hydraulic line G. Regulator 13 closes when its solenoid is energized and opens when its solenoid is deenergized based on a command from control device 50. Regulator 13 is configured to adjust its valve-opening pressure by controlling the current flowing through the solenoid (it also functions as a relief valve). That is, when the pressure difference between branch hydraulic line E and pressurized hydraulic line F becomes equal to or greater than the valve-opening pressure (when the brake fluid pressure in pressurized hydraulic line F becomes equal to or greater than the brake fluid pressure obtained by adding the brake fluid pressure in branch hydraulic line E to the valve-opening pressure), regulator 13 allows brake fluid discharged from pressurizing pump 12 to pressurizing hydraulic line F to return (return) through communicating hydraulic line G to the suction side of pressurizing pump 12, which is branch hydraulic line E. Specifically, the regulator 13 is closed under the control of the control device 50 when pressurization control, which will be described later, is performed. The regulator 13 opens when the differential pressure between the brake fluid pressure in the pressurized hydraulic line F and the brake fluid pressure in the branch hydraulic line E becomes equal to or greater than the valve opening pressure. When the valve opens, brake fluid flows from the pressurized hydraulic line F to the branch hydraulic line E through the communicating hydraulic line G. In this way, the brake fluid flows from the pressurized hydraulic line F to the branch hydraulic line E through the regulator 13, thereby adjusting the brake fluid pressure on the pressurized hydraulic line F side to a predetermined pressure.

[0042] For example, when performing pressure control in the linked brake control based on input from the rear wheel brake operator described below, the regulator 13 adjusts the magnitude of the current passed through the solenoid so that the valve opening pressure corresponds to the input from the rear wheel brake operator. In addition, when pressure reduction control is performed by releasing the brake operator on the rear wheel in similar linked brake control, the regulator 13 adjusts the magnitude of the current passed through the solenoid so that the valve opening pressure is based on the release of the brake operator on the rear wheel. Furthermore, even if anti-lock brake control is requested during similar interlocking brake control, the regulator 13 adjusts the magnitude of the current flowing through the solenoid so that the valve opening pressure is based on the pressure reduction, pressure increase or pressure maintenance of the anti-lock brake control.

[0043] When the front wheel brake operation element L1 is operated alone, the solenoid of the regulator 13 is de-energized and the valve is opened whether the anti-lock brake is not being controlled or is being controlled. A check valve 13a is connected in parallel to the regulator 13. The check valve 13a is a valve that only allows brake fluid (hydraulic fluid) to flow from the master cylinder M to the second wheel cylinder W2. When the brake operator L1 is applied, the check valve 13a allows brake fluid to flow from the master cylinder M to the second wheel cylinder W2 even when the regulator 13 is closed. The check valve 13a is provided integrally with a normally open solenoid valve that constitutes the regulator 13.

[0044] The hydraulic pressure sensor 14 is disposed in the branch hydraulic line E. The hydraulic pressure sensor 14 measures the brake hydraulic pressure in the branch hydraulic line E, i.e., the magnitude of the brake hydraulic pressure on the master cylinder M side. The value of the brake hydraulic pressure measured by the hydraulic pressure sensor 14 is constantly input to the control device 50, which determines whether or not brake hydraulic pressure is being output from the master cylinder M, i.e., whether or not the front wheel brake operator L1 is being operated. Furthermore, based on the magnitude of the brake hydraulic pressure measured by the hydraulic pressure sensor 14, pressurization control and the like are performed.

[0045] The control device 50 controls the opening and closing of the regulator 13, the inlet valve 2, the outlet valve 3, and the driving of the motor 6 (driving the pump 5 and the pressurizing pump 12) based on outputs from external sensors such as the hydraulic pressure sensor 14, a wheel speed sensor (not shown), and an acceleration sensor that measures the movement of the vehicle body.

[0046] Next, the operation of the hydraulic circuit of the brake control device 1 will be described in detail. First, the operation of the hydraulic circuit when the front wheel brake operator L1 is operated alone will be described with reference to Figures 3A to 3E. In Figures 3A to 3E, the hydraulic paths indicated by "thick solid lines" indicate hydraulic paths where hydraulic pressure equivalent to the brake hydraulic pressure generated in the master cylinder M (hereinafter referred to as master cylinder pressure) acts, and the hydraulic paths indicated by "thin broken lines" indicate hydraulic paths where hydraulic pressure smaller than the master cylinder pressure acts.

[0047] (anti-lock brakes not controlled) When the antilock brakes are not being controlled and there is no possibility that the front wheels will lock, the solenoids of the inlet valve 2, outlet valve 3, and regulator 13 are all de-energized by the control device 50. That is, as shown in Fig. 3A, when the antilock brakes are not being controlled, the inlet valve 2 and regulator 13 are open, and the outlet valve 3 is closed. In this state, when the driver operates the front wheel brake operator L1, the brake fluid pressure generated by the operation force is transmitted to the first wheel cylinders W1, W1 through the output fluid pressure line A and the wheel fluid pressure line B, as shown by the thick solid lines in the figure, and is also transmitted to the second wheel cylinder W2 through the branch fluid pressure line E, the connecting fluid pressure line G, and the pressurized fluid pressure line F. This causes the front wheels to brake.

[0048] On the other hand, when the driver releases the front wheel brake operator L1, as shown in Figure 3B, the brake fluid returns to the master cylinder M through each hydraulic path, and the brake fluid pressure transmitted to the first wheel cylinder W1, W1 and the second wheel cylinder W2 is released.

[0049] (Anti-lock brake control) Antilock brake control is executed when the front wheels are about to lock up, and is realized by appropriately selecting a state in which the brake fluid pressure acting on the wheel brakes W is reduced, increased, or maintained constant. The selection of reducing, increasing, or maintaining the pressure is determined by the control device 50 based on the wheel speed obtained from a wheel speed sensor (not shown). During antilock brake control when the front wheel brake operator L1 is operated alone, the branch hydraulic line E does not become negative pressure, so the brake fluid stored in the pressurizing reservoir 11 is not sucked in.

[0050] If the front wheels are about to lock while the front wheel brake operator L1 is being operated, anti-lock brake control is initiated by the control device 50. When the anti-lock brake control is executed, the control device 50 drives the motor 6, which drives the pump 5 and the pressure pump 12.

[0051] During pressure reduction control during antilock brake control, as shown in FIG. 3C, the control device 50 closes the inlet valve 2 and opens the outlet valve 3. The solenoid of the regulator 13 is deenergized by the control device 50, maintaining the regulator 13 in an open state. As a result, as shown by the thin dashed lines in the figure, brake fluid flowing to the first wheel cylinders W1, W1 of the wheel brake W flows into the reservoir 4 through the wheel hydraulic pressure line B and the open passage C. Brake fluid flowing to the second wheel cylinder W2 of the wheel brake W flows into the reservoir 4 through the pressurized hydraulic pressure line F, the connecting hydraulic pressure line G, the branched hydraulic pressure line E, the wheel hydraulic pressure line B, and the open passage C. As a result, the brake hydraulic pressure acting on the first wheel cylinders W1, W1 and the second wheel cylinder W2 is reduced. The brake fluid temporarily stored in the reservoir 4 is sucked by the pump 5 and returned to the master cylinder M through the discharge hydraulic pressure line D and the output hydraulic pressure line A.

[0052] In this case, on the pressurized hydraulic circuit HP2 side, the brake fluid discharged from the branch hydraulic line E to the pressurized hydraulic line F by the operation of the pressurizing pump 12 is returned to the branch hydraulic line E through the regulator 13 of the communicating hydraulic line G, so no pressure increase occurs due to the operation of the pressurizing pump 12.

[0053] During pressure increase control during antilock brake control, as shown in Fig. 3D, the control device 50 sets the inlet valve 2 to a valve opening pressure based on the pressure increase control and closes the outlet valve 3. In this manner, as shown by the thin dashed line in the figure, the brake fluid pressure generated by the operating force of the front wheel brake operator L1 is adjusted to a predetermined level by the inlet valve 2 and acts on the first wheel cylinders W1, W1. On the pressurized hydraulic circuit HP2 side, the brake fluid pressure adjusted to a predetermined level by the inlet valve 2 acts on the second wheel cylinder W2 through the branch hydraulic pressure line E, the check valve 13a, and the pressurized hydraulic pressure line F. As a result, the brake fluid pressure acting on the wheel brake W is increased. In this case, on the pressurized hydraulic circuit HP2 side, the brake fluid discharged from the branch hydraulic line E side to the pressurized hydraulic line F side by the operation of the pressurizing pump 12 is returned to the branch hydraulic line E through the regulator 13 of the communicating hydraulic line G, so no pressure increase occurs due to the operation of the pressurizing pump 12.

[0054] The brake fluid pressure holding control during antilock brake control is a control to hold the brake fluid pressure constant. In this holding control, the control device 50 closes the inlet valve 2 and the outlet valve 3, as shown in FIG. 3E. In this way, the brake fluid pressure from the master cylinder M is blocked by the inlet valve 2, as indicated by the thin dashed line in the figure. The brake fluid is then trapped in the flow path closed by the inlet valve 2 and the outlet valve 3. As a result, the brake fluid pressure acting on the first wheel cylinder W1, W1 and the second wheel cylinder W2 is held constant. In this case, the pressurizing pump 12 is simply driven within the closed pressurized hydraulic circuit HP2, and therefore no pressure increase occurs due to the driving of the pressurizing pump 12.

[0055] Next, the operation of the front wheel hydraulic circuit during interlocking brake control will be described with reference to Figures 4A to 4C. In Figures 4A to 4C, the hydraulic paths indicated by "thick dashed lines" indicate hydraulic paths where hydraulic pressure greater than the master cylinder pressure acts. The interlocking brake control is executed when the rear wheel brake operator is operated, depending on the magnitude of the braking force caused by that operation, and is realized by applying brake fluid pressure to the second wheel cylinder W2 via the pressurized fluid pressure circuit HP2. Whether or not to execute the interlocking brake control is determined by the control device 50.

[0056] (When anti-lock brake control is not in use with linked brake control) The interlocking brake control is a control that applies brake fluid pressure to the front wheel brake W (wheel cylinder W2) when the driver operates the brake operator for the rear wheels. When the interlocking brake control is executed, as shown in Fig. 4A, the electric motor 6 is driven and the pressurizing pump 12 of the front wheel pressurizing fluid pressure circuit HP2 is operated. Then, the regulator 13 is adjusted to maintain the valve opening pressure according to the input of the brake operator for the rear wheels. When the pressurizing pump 12 is operated, the branch hydraulic line E becomes negative pressure, and brake fluid is sucked from the nearest pressurizing reservoir 11. At this time, in the pressurizing reservoir 11, as shown in FIG. 2(b), the diaphragm 110 is lifted off the plug 120, and brake fluid flows from the reservoir chamber 11a through the communication passage E2 to the branch hydraulic line E.

[0057] Brake fluid pressure generated by the operation of the pressurizing pump 12 is transmitted to the second wheel cylinder W2 through the pressurized hydraulic line F, as shown by the thick dashed line in FIG. 4A. This automatically controls the pressure of the brake fluid in the second wheel cylinder W2. At this time, the regulator 13, whose valve opening pressure is adjusted, returns excessively pressurized brake fluid to the branch hydraulic line E through the communicating hydraulic line G. This adjusts the brake fluid pressure in the pressurized hydraulic line F to a brake fluid pressure corresponding to the input of the brake operator for the rear wheel.

[0058] When the driver subsequently releases the rear wheel brake operator, the current flowing through regulator 13 is reduced to adjust the valve opening pressure, and as shown in Figure 4B, the brake fluid in second wheel cylinder W2 is returned to pressurizing reservoir 11 of branch hydraulic line E through communicating hydraulic line G. This releases the brake fluid pressure that had been transmitted to second wheel cylinder W2.

[0059] (When anti-lock brake control is used with linked brake control) The antilock brake control in the interlocking brake control is executed when the front wheels are about to lock up during interlocking brake control, and is realized by appropriately selecting a state in which the brake fluid pressure acting on the second wheel cylinder W2 is reduced, increased, or maintained constant. In this case, the control device 50 determines whether to reduce, increase, or maintain the pressure based on the wheel speed obtained from a wheel speed sensor (not shown).

[0060] When the front wheel brake operator L1 is not operated and only the rear wheel brake operator is operated, and the pressurized hydraulic circuit HP2 is performing interlocking brake control (automatic pressurization control), if the front wheel is about to lock, the control device 50 starts anti-lock brake control. During pressure reduction control of the antilock brake control, the current supplied to regulator 13 is reduced to adjust the valve opening pressure to a lower value. As a result, as shown in FIG. 4C, brake fluid is returned to pressurizing reservoir 11 of branch hydraulic line E through communicating hydraulic line G. This reduces the brake fluid pressure transmitted to second wheel cylinder W2. In this case, inlet valve 2 may be closed to prevent brake fluid from being supplied from master cylinder M to branch hydraulic line E.

[0061] During pressure increase control during antilock brake control, the current supplied to regulator 13 is increased to adjust the valve opening pressure. This causes brake fluid to be drawn from the nearest pressurizing reservoir 11, and brake fluid pressure is transmitted to second wheel cylinder W2 through pressurized hydraulic line F, as in FIG. 4A. This increases the pressure in second wheel cylinder W2. Note that, with the valve opening pressure adjusted by regulator 13, excessively increased brake fluid is returned to branch hydraulic line E through communicating hydraulic line G.

[0062] During the holding control during antilock brake control, the current flowing through regulator 13 is maintained, thereby maintaining the valve opening pressure. This causes the brake fluid pressure in pressurized hydraulic line F to be trapped, as shown by the thick dashed line in FIG. 4A. As a result, the brake fluid pressure acting on second wheel cylinder W2 is maintained constant. Excessively retained brake fluid is returned to branch hydraulic line E through communicating hydraulic line G by regulator 13, whose valve opening pressure is adjusted. Note that inlet valve 2 may be closed to prevent brake fluid from being supplied from master cylinder M to branch hydraulic line E.

[0063] Next, the operation of the front wheel hydraulic circuit when the front wheel brake operator L1 is operated first and then the rear wheel brake operator is additionally operated (additional input) will be described with reference to Figures 5A and 5B. In Figures 5A and 5B, the hydraulic paths indicated by "thick solid lines" are the same as those described above. Furthermore, the hydraulic paths indicated by "thick dashed lines" indicate hydraulic paths where hydraulic pressure greater than the master cylinder pressure acts. When the front wheel brake operating element L1 is operated, as described above, the brake fluid pressure generated by the operating force is transmitted to the first wheel cylinders W1, W1 through the output hydraulic pressure path A and the wheel hydraulic pressure path B, and is also transmitted to the second wheel cylinder W2 through the branch hydraulic pressure path E, the connecting hydraulic pressure path G and the pressurized hydraulic pressure path F (see Figure 3A). When the rear wheel brake operator is operated from this state and interlocking brake control (automatic pressurization control) is executed, as shown in Fig. 5A, the regulator 13 opens, the electric motor 6 is driven, and the pressurization pump 12 operates. This causes brake fluid to be sucked from the master cylinder M and discharged from the branch hydraulic line E to the pressurization hydraulic line F via the pressurization pump 12, increasing the pressure in the pressurization hydraulic line F by the amount caused by the interlocking brake control. In this case, since the brake operator L1 of the front wheel is operated, brake fluid is sucked in by the operation of the pressurization pump 12, so that the front wheel brake operator L1 moves further in the operating direction. The pressurization reservoir 11 is pressed against the atmosphere by the master cylinder pressure.

[0064] If, for example, the front wheel brake operator L1 is released from this state, the brake fluid pressure transmitted by the master cylinder M to the first wheel cylinder W1, W1 and the second wheel cylinder W2 is reduced, as shown in Fig. 5B, and the brake fluid returns to the master cylinder M through the respective hydraulic lines. If the rear wheel brake operator remains operated, even if the front wheel brake operator L1 is released, the pressure pump 12 continues to operate with the regulator 13 maintaining the valve opening pressure through the interlocking brake control. Therefore, the brake fluid pressure generated by the operation of the pressure pump 12 is transmitted to the second wheel cylinder W2 through the hydraulic pressure line F, as shown by the thick dashed line in the figure. As a result, the front wheels are braked by brake fluid pressure corresponding to the input of the rear wheel brake operator.

[0065] Next, antilock brake control when the front wheel brake operator L1 is operated first and then the rear wheel brake operator is additionally operated (additional input) will be described with reference to Figures 5C and 5D. In Figures 5C and 5D, the fluid paths indicated by the "thick solid line" and "thin dashed line" are the same as those described above. In addition, the fluid path indicated by the "thick two-dot chain line" indicates a fluid path where a fluid pressure smaller than the master cylinder pressure and greater than the fluid pressure of the fluid path indicated by the "thin dashed line" acts. In this case, the antilock brake control is also executed when the front wheels are about to lock up, and is realized by appropriately selecting a state in which the brake fluid pressure acting on the first wheel cylinder W1, W1 and the second wheel cylinder W2 is reduced, increased, or maintained constant. The control device 50 determines whether to reduce, increase, or maintain the pressure based on the wheel speeds obtained from wheel speed sensors (not shown).

[0066] 5C, in the pressure reduction control during antilock brake control, in the main hydraulic circuit HP1, the control device 50 closes the inlet valve 2 and opens the outlet valve 3 in the same manner as described above. This causes the brake fluid flowing to the first wheel cylinders W1, W1 to flow into the reservoir 4 through the wheel hydraulic pressure path B and the open path C. Meanwhile, in the pressurized hydraulic circuit HP2, the current flowing through the regulator 13 is reduced to adjust the valve opening pressure lower. This causes brake fluid to flow into the reservoir 4 through the pressurized hydraulic line F, the communicating hydraulic line G, the branch hydraulic line E, the wheel hydraulic line B, and the open line C. As a result, the brake fluid pressure acting on the first wheel cylinder W1, W1 and the second wheel cylinder W2 is reduced. Note that the pressure reduction control is performed with the diaphragm 110 of the pressurized reservoir 11 pressed against the atmosphere, so brake fluid does not flow into the pressurized reservoir 11 during the pressure reduction control.

[0067] During pressure increase control during antilock brake control, as shown in FIG. 5D, inlet valve 2 is set to a valve opening pressure based on the pressure increase control, and outlet valve 3 is closed. In this state, brake fluid pressure generated by the operating force of front wheel brake operator L1 is adjusted to a predetermined level by inlet valve 2 and acts on first wheel cylinder W1, W2. In addition, in pressurized hydraulic circuit HP2, the current supplied to regulator 13 is increased to adjust the valve opening pressure. As a result, the brake fluid pressure adjusted to a predetermined level by inlet valve 2 is drawn into pressurizing pump 12 through branch hydraulic line E. As shown by the thick two-dot chain line in FIG. 5D, the increased brake fluid is transmitted to second wheel cylinder W2 through pressurized hydraulic line F. With the valve opening pressure adjusted by regulator 13, excessively increased brake fluid is returned to branch hydraulic line E through communicating hydraulic line G.

[0068] Furthermore, during the holding control during antilock brake control, the control device 50 closes the inlet valve 2 and the outlet valve 3. In this manner, the inlet valve 2 cuts off the brake fluid pressure from the master cylinder M. The brake fluid is then trapped within the flow path closed by the inlet valve 2 and the outlet valve 3. As a result, the brake fluid pressure acting on the first wheel cylinders W1, W1 is maintained constant in the main hydraulic circuit HP1. In the pressurized hydraulic circuit HP2, the current flowing through the regulator 13 is maintained, and the valve opening pressure is maintained. This then traps the brake fluid pressure in the pressurized hydraulic line F, as shown by the thick two-dot chain line in Figure 5D. As a result, the brake fluid pressure acting on the second wheel cylinder W2 is maintained constant. Note that with the valve opening pressure adjusted, the regulator 13 allows excess retained brake fluid to flow back to the branch hydraulic line E through the communicating hydraulic line G.

[0069] Next, the operation of the front wheel hydraulic circuit when the rear wheel brake operator is operated first and then the front wheel brake operator L1 is operated (additional input) will be described with reference to Figures 6A and 6B. In Figures 6A and 6B, the hydraulic paths indicated by "thick solid lines" and "thick dashed lines" are the same as those described above. When the rear wheel brake operator is operated, as described above, the electric motor 6 is driven and the pressure pump 12 is activated. Then, the regulator 13 is adjusted to maintain the valve opening pressure according to the input of the rear wheel brake operator (see FIG. 4A). When the pressurizing pump 12 is operated, the branch hydraulic line E becomes negative pressure, and brake fluid is sucked from the nearest pressurizing reservoir 11. This causes the diaphragm 110 to separate from the plug 120 (see FIG. 2(b)).

[0070] If the front wheel brake operator L1 is operated from this state, the brake fluid pressure generated by the operation force is transmitted to the first wheel cylinders W1, W1 through the output fluid pressure path A and the wheel fluid pressure path B as shown by the thick solid lines in Figure 6A, and the released diaphragm is returned to its initial position. This alleviates the phenomenon where the operation feel of the front wheel brake operator L1 becomes stiff when additional input is made to the front wheel brake operator L1. Meanwhile, in the pressurized hydraulic circuit HP2, due to the operation of the front wheel brake operator L1, brake fluid flows from the wheel hydraulic line B into the branch hydraulic line E, and then into the pressurizing reservoir 11. This causes the front wheel brake operator L1 to move further in the operating direction.

[0071] From this state, for example, when the rear wheel brake operator is released, the current flowing through regulator 13 is reduced to adjust the valve opening pressure, and as shown by the thick solid line in Figure 6B, the brake fluid pressurized by pressurizing pump 12 and acting on pressurized hydraulic line F is returned to master cylinder M through communicating hydraulic line G, branch hydraulic line E, wheel hydraulic line B, and output hydraulic line A. As a result, the brake fluid pressure transmitted to second wheel cylinder W2 by the rear wheel brake operator is released, and the front wheels are braked by brake fluid pressure corresponding to the input of front wheel brake operator L1.

[0072] In addition, the operation of the front wheel hydraulic circuit in antilock brake control when the rear wheel brake operator is operated first and then the front wheel brake operator L1 is operated subsequently is the same as the operation described above based on Figures 5C and 5D, so explanation will be omitted.

[0073] According to the brake control device 1 of this embodiment described above, the master cylinder pressure acts on the first wheel cylinders W1, W1 through the main hydraulic circuit HP1. Meanwhile, the brake fluid pressure acts on the second wheel cylinder W2 through the pressurized hydraulic circuit HP2 branching off from the main hydraulic circuit HP1. In other words, the brake fluid pressure acts on the first wheel cylinders W1, W1 and the second wheel cylinder W2 through different paths. As a result, when the front wheel brake operator L1 is additionally operated during automatic front wheel pressurization control, where brake fluid pressure is acting on the second wheel cylinder W2 due to operation of the rear wheel brake operator, the master cylinder pressure acts on the first wheel cylinder W1, W1 through the main hydraulic circuit HP1. In other words, due to the automatic brake fluid pressure control, the brake fluid pressure acting on the wheel brake W is increased by the amount of brake fluid pressure acting on the wheel brake W due to operation of the rear wheel brake operator. Therefore, the amount of operation of the front wheel brake operator L1 matches the vehicle deceleration, providing a good braking feel.

[0074] Furthermore, when the front wheel brake operator L1 is operated and automatic brake fluid pressure increase control is executed by operating the rear wheel brake operator, brake fluid is drawn from the master cylinder M by the pressurizing pump 12 provided in the pressurized fluid circuit HP2 and acts on the second wheel cylinder W2 through the pressurized fluid circuit HP2. This causes the front wheel brake operator L1 to move further in the operating direction. Therefore, the amount of operation of the front wheel brake operator L1 matches the vehicle deceleration, providing a good braking feel.

[0075] Furthermore, the valve opening pressure of the pressurizing pump 12 is set to be lower than atmospheric pressure and is self-suctioning, so there is no need to provide a suction control valve in the pressurized hydraulic circuit HP2, and the number of control valves in the hydraulic circuit can be minimized, thereby reducing costs.

[0076] Furthermore, since brake fluid is drawn from the pressurization reservoir 11 during automatic brake fluid pressure pressurization control, it can be drawn through a shorter flow path than when drawing from the master cylinder M. Furthermore, when the front wheel brake operator L1 is operated during automatic brake fluid pressure pressurization control, the brake fluid from the master cylinder M acts on the first wheel cylinders W1, W1 and also flows into the pressurization reservoir 11. This prevents the input from the brake lever from becoming too stiff, and the amount of operation of the front wheel brake operator L1 matches the vehicle deceleration, providing a good braking feeling.

[0077] Furthermore, since the regulator 13 is provided in the pressurized hydraulic circuit HP2, the brake fluid in the pressurized hydraulic circuit HP2 can be returned through the regulator 13, thereby enabling pressure regulation in the pressurized hydraulic circuit HP2.

[0078] Furthermore, since the pressurizing reservoir 11 is configured with a simple structure that utilizes the elastic deformation of the diaphragm 110, the number of parts and costs can be reduced.

[0079] Furthermore, since the first wheel cylinders W1, W1 and the second wheel cylinder W2 are provided in one caliper body, the number of parts and costs can be reduced compared to double-disc wheel brakes.

[0080] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention. In the above embodiment, the pressurized hydraulic circuit HP2 is provided in the hydraulic circuit on the front wheel side, but this is not limited to this. The pressurized hydraulic circuit HP2 may be provided in the hydraulic circuit on the rear wheel side, or the pressurized hydraulic circuit HP2 may be provided in each of the hydraulic circuits on both the front and rear wheels.

[0081] The pressurizing reservoir 11 may be of any type as long as it can store brake fluid in preparation for automatic pressurizing control, and various types and shapes may be employed.

[0082] In addition, in the above embodiment, the "pressurization control" has been described as an example of "automatic pressurization control" that is executed during interlocking brake control, but this is not limited to this, and the pressurized hydraulic circuit HP2 may be automatically pressurized during control other than interlocking brake control, for example, without being caused by operation of the brake operator on the rear wheel. [Explanation of symbols]

[0083] 1. Vehicle brake fluid pressure control device (brake control device) 2 inlet valve 3 Outlet Valve 4 Reservoir 5. Pump 11 Pressurized reservoir 11a Liquid storage chamber 11b Atmospheric chamber 12 Pressure pump 13 Regulator 24 Branch 110 diaphragm 120 plug 125 Communication path HP1 Main hydraulic circuit HP2 pressurized hydraulic circuit L1 Front wheel brake operator M master cylinder W wheel brake W1 No. 1 wheel cylinder W2 No. 2 wheel cylinder

Claims

1. A vehicle brake fluid pressure control device including a fluid pressure circuit disposed between a master cylinder that generates hydraulic fluid pressure in accordance with an operation amount of a brake operator and wheel brakes that are operated by the hydraulic pressure of the supplied hydraulic fluid, The wheel brake includes a first wheel cylinder and a second wheel cylinder, The hydraulic circuit includes: a main hydraulic circuit extending from the master cylinder to the first wheel cylinder; a normally open solenoid valve and a normally closed solenoid valve provided in the main hydraulic circuit; a pressurized hydraulic circuit branching off from a position between the normally open solenoid valve and the first wheel cylinder in the main hydraulic circuit and leading to the second wheel cylinder, The pressurizing hydraulic circuit is provided with a pressurizing pump, the pressurizing pump is provided with a suction valve whose valve opening pressure is lower than atmospheric pressure and is capable of self-suction; the pressurizing hydraulic circuit includes a pressurizing reservoir between a branch point with the main hydraulic circuit and a suction side of the pressurizing pump, 10. A vehicle brake fluid pressure control device, wherein the pressurizing reservoir initially stores hydraulic fluid.

2. 2. The vehicle brake fluid pressure control device according to claim 1, 10. A vehicle brake fluid pressure control device, comprising: a pressure regulating valve for controlling a valve opening pressure, the pressure regulating valve being provided in the pressurized fluid pressure circuit.

3. 3. The vehicle brake fluid pressure control device according to claim 1, the pressurizing reservoir includes a diaphragm and a plug on which the diaphragm is seated, and is partitioned by the diaphragm into a liquid storage chamber and an atmospheric chamber; 10. A vehicle brake fluid pressure control device, comprising: a plug having a communication passage communicating with the atmosphere;

4. 4. The vehicle brake fluid pressure control device according to claim 1, 10. A brake fluid pressure control device for a vehicle, wherein the first wheel cylinder and the second wheel cylinder are provided in a single caliper body.

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