JP6359976B2 - Hydraulic brake system - Google Patents

Description

  The present invention relates to a hydraulic brake system for a vehicle that includes a master cylinder and a regulator.

In Patent Document 1 below, a master cylinder that supplies pressurized hydraulic fluid to a brake device, a regulator that supplies hydraulic fluid regulated to the master cylinder, and hydraulic fluid adjusted to an arbitrary pressure by control are provided. A hydraulic brake system that includes a hydraulic fluid supply device that supplies a regulator is described. The master cylinder is (A-1) an input piston connected to the brake operation member and advanced by operation of the brake operation member, and (A-2) a pressure piston disposed in front of the input piston, (A-3) an inter-piston chamber formed between the input piston and the pressurizing piston; (A-4) a pressurization chamber formed in front of the pressurization piston; and (A-5) an inter-piston chamber. And an input chamber into which hydraulic fluid for applying a forward force to the pressurizing piston is introduced, depending on at least one of the hydraulic pressure in the inter-piston chamber and the hydraulic pressure in the input chamber The pressurizing piston is advanced, and the hydraulic fluid in the pressurizing chamber pressurized by the advancement of the pressurizing piston is supplied to the brake device.
Also, (B-1) an adjustment pressure chamber containing hydraulic fluid adjusted to the adjustment pressure, and (B-2) adjustable from one end side in its movable range that is movable in the axial direction of the regulator. When the valve body that receives the hydraulic pressure of the pressure chamber is located on the other end side in the movable range, the low pressure source and the adjustment pressure chamber are allowed to communicate, and the high pressure source and the adjustment pressure chamber A valve mechanism that blocks communication between the low pressure source and the regulated pressure chamber by allowing the valve body to move to one end side, and permits communication between the high pressure source and the regulated pressure chamber, and (B- 3) A pilot piston disposed on the other end of the valve body, and (B-4) hydraulic fluid that is formed on the other end of the pilot piston and is pressurized from the pressurizing chamber of the master cylinder. The first pilot pressure chamber, and (B-5) is formed between the pilot piston and the valve body. And a second pilot pressure chamber into which the adjusted hydraulic fluid is introduced. (I) The pilot piston comes into contact with the valve body by the first pilot pressure, which is the hydraulic pressure of the first pilot pressure chamber, together with the valve body The valve body is moved by the first state in which the adjustment pressure is adjusted to a magnitude corresponding to the first pilot pressure by the movement, and (II) the second pilot pressure which is the hydraulic pressure of the second pilot pressure chamber. Thus, the second state in which the adjustment pressure is adjusted to the magnitude corresponding to the second pilot pressure is selectively realized, and the adjusted hydraulic fluid is supplied to the input chamber of the master cylinder. It is configured.

JP2013-227016A

  In the hydraulic brake system configured as described above, for example, when the control device of this system is activated on the condition that the brake operation is performed, the brake operation is performed after the brake operation is started. In this state, the first state is switched to the second state. That is, the second pilot, which is the hydraulic pressure of the hydraulic fluid introduced from the hydraulic fluid supply device, from the state of being regulated by the first pilot pressure, which is the hydraulic pressure of the hydraulic fluid introduced from the pressurizing chamber of the master cylinder. In order to change to a state in which the pressure is regulated by the pressure, fluctuation of the hydraulic pressure in the adjustment pressure chamber becomes a problem. In other words, it is considered that the practicality of the hydraulic brake system can be improved by dealing with such a problem. This invention is made | formed in view of such a situation, and makes it a subject to provide a practical hydraulic brake system.

  In order to solve the above problems, the hydraulic brake system of the present invention is a control of the second pilot pressure in the second state when switching from the first state to the second state after the operation of the brake operation member is started. Before starting the feedback control, the hydraulic fluid is temporarily supplied to the second pilot pressure chamber in a state where the valve body and the pilot piston are in contact with each other, and then the valve body and the pilot piston are separated from each other to adjust the adjustment pressure. The second pilot pressure preparatory control for supplying the hydraulic fluid to the second pilot pressure chamber at a flow rate larger than the flow rate when supplying the hydraulic fluid with the valve body and the pilot piston in contact with each other until the pressure is reached is executed. It is characterized by that.

  The hydraulic brake system of the present invention supplies hydraulic fluid to the second pilot pressure chamber relatively slowly until the valve body and the pilot piston are separated by the second pilot pressure preparation control, and then the adjustment pressure is adjusted. Until the target hydraulic pressure is reached, the hydraulic pressure in the second pilot pressure chamber can be quickly increased. Therefore, according to the hydraulic brake system of the present invention, when switching from the first state to the second state after the operation of the brake operation member is started, the transition time from the first state to the second state is relatively short. Is possible.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following items, item (1) corresponds to item 1, and the technical feature described in item (2) is added to item 1 and item 2 or item 1 or item 2. The technical feature described in (6) is added to 2 in claim 3, and the technical feature described in (7) is added in claim 3 in claim 4, in claim 3 or The technical feature described in (8) is added to claim 4 and the technical feature described in (3) is added to any one of claims 1 to 5 in claim 5. The present invention corresponds to claim 6, and any one of claims 1 to 6 to which the technical features described in the items (9) and (10) are added corresponds to claim 7.

(1) a brake operation member operated by a driver;
A brake device that is provided on the wheel and generates a braking force having a magnitude corresponding to the pressure of the hydraulic fluid supplied to the wheel;
(A-1) an input piston connected to the brake operation member and advanced by operation of the brake operation member; (A-2) a pressure piston disposed in front of the input piston; and (A- 3) an inter-piston chamber formed between the input piston and the pressurizing piston; (A-4) a pressurization chamber formed in front of the pressurizing piston; and (A-5) an inter-piston space. And an input chamber into which hydraulic fluid for applying a forward force to the pressurizing piston is introduced, and at least one of a hydraulic pressure in the inter-piston chamber and a hydraulic pressure in the input chamber A master cylinder for advancing the pressurizing piston and supplying hydraulic fluid in the pressurizing chamber pressurized by the advancement of the pressurizing piston to the brake device;
A high pressure source for supplying high pressure hydraulic fluid;
A regulator that regulates the high-pressure hydraulic fluid from the high-pressure source to a regulated pressure, and supplies the regulated hydraulic fluid to the input chamber of the master cylinder, and (B-1) regulates the regulated pressure to the regulated pressure (B-2) a valve body that is movable in the axial direction of the regulator and that receives the hydraulic pressure of the adjustment pressure chamber from one end side in its movable range. When the valve body is located on the other end side in the movable range, communication between the low pressure source and the adjustment pressure chamber is allowed, and communication between the high pressure source and the adjustment pressure chamber is blocked. A valve mechanism that blocks communication between the low pressure source and the adjustment pressure chamber by moving to one end side of the body, and permits communication between the high pressure source and the adjustment pressure chamber; and (B-3) the valve body (B-4) on the other end of the pilot piston A first pilot pressure chamber formed and introduced with hydraulic fluid pressurized from the pressurization chamber of the master cylinder; and (B-5) a second formed between the pilot piston and the valve body. A pilot pressure chamber; and (I) the pilot piston is brought into contact with the valve body and moved together with the valve body by a first pilot pressure which is a hydraulic pressure of the first pilot pressure chamber, so that the adjustment pressure is The valve body is moved by a first state that is regulated to a magnitude corresponding to the first pilot pressure, and (II) a second pilot pressure that is a hydraulic pressure of the second pilot pressure chamber, thereby the adjustment A regulator that selectively realizes a second state in which the pressure is regulated to a magnitude corresponding to the second pilot pressure;
A second pilot pressure chamber hydraulic fluid supply device for supplying hydraulic fluid to the second pilot pressure chamber of the regulator and generating hydraulic pressure in the second pilot pressure chamber;
A hydraulic brake system including a control device that controls the second pilot pressure by controlling the second pilot pressure chamber hydraulic fluid supply device to control the adjusted pressure,
The control device is
In the second state, the second pilot pressure is set to a deviation between an actual hydraulic pressure in the adjustment pressure chamber and a target hydraulic pressure in the adjustment pressure chamber determined in accordance with an operation performed on the brake operation member. Based on feedback control,
In the case of switching from the first state to the second state after the operation of the brake operation member is started, the second body is in contact with the valve body and the pilot piston before the feedback control is started. The hydraulic fluid is once supplied to the pilot pressure chamber, and then the valve body and the pilot piston are brought into contact with each other until the valve body and the pilot piston are separated and the adjustment pressure reaches the target hydraulic pressure. A hydraulic brake system characterized by executing second pilot pressure preparation control for supplying hydraulic fluid to the second pilot pressure chamber at a flow rate larger than a flow rate when supplying hydraulic fluid in a state.

  The hydraulic brake stem described in this section includes (I) a first state in which the pilot piston moves together with the valve body by the first pilot pressure that is the hydraulic pressure of the hydraulic fluid introduced from the master cylinder. And (II) a regulator that selectively realizes the second state in which the valve body is adjusted by the movement of the valve body by the second pilot pressure that is the hydraulic pressure of the hydraulic fluid introduced from the hydraulic fluid supply device. It is assumed that In such a regulator, in the first state, the second pilot pressure chamber is connected to the low pressure source, and when switching from the first state to the second state, the hydraulic pressure in the second pilot pressure chamber is reduced to the low pressure source. It is necessary to raise from the hydraulic pressure at once.

  In addition, when switching from the first state to the second state, there is also a factor that the time required for the switching becomes long. Specifically, for example, (i) there is a range in which the hydraulic pressure does not increase even if hydraulic fluid is introduced into the second pilot pressure chamber due to the presence of a seal or the like provided in a portion that forms the second pilot pressure chamber. (Ii) When switching from the first state to the second state in a state where the brake operation is performed after the brake operation is started, the regulator and the pilot piston are caused by the increase in the hydraulic pressure in the second pilot pressure chamber in the regulator. May cause the valve body to retreat and the hydraulic pressure in the adjustment pressure chamber to drop, and (iii) even if the operation amount of the brake operation member is the same, the input of the master cylinder For example, the fluid pressure in the chamber, that is, the fluid pressure in the regulator pressure chamber of the regulator may be higher in the second state than in the first state.

  The hydraulic brake system described in this section reliably creates the state immediately before the pilot piston and the valve body are separated by the second pilot pressure preparation control and pressure adjustment according to the first pilot pressure is not performed. After that, the hydraulic pressure in the second pilot pressure chamber can be increased at a stroke. Therefore, according to the hydraulic brake system of this section, as compared with the case where the feedback control is executed without executing the second pilot pressure preparation control, the time required for the transition from the first state to the second state, Specifically, it is possible to shorten the time from when the first state disappears until the second state is realized.

(2) The second pilot pressure preparation control is
The hydraulic fluid is once supplied to the second pilot pressure chamber until the hydraulic fluid having a set fluid amount set so as not to separate the valve body and the pilot piston is introduced. The hydraulic brake system according to (1), wherein the hydraulic fluid is supplied to the second pilot pressure chamber at a flow rate larger than a flow rate when supplying the liquid to the second pilot pressure chamber.

  The mode described in this section is a mode in which the condition for increasing the flow rate of supplying hydraulic fluid to the second pilot pressure chamber in the second pilot pressure preparation control is embodied, and the set fluid amount is introduced into the second pilot pressure chamber. When it is detected or estimated that the operation has been performed, the flow rate can be increased. Due to the structure of the regulator, there is a range in which the second pilot pressure does not increase even if hydraulic fluid is introduced into the second pilot pressure chamber due to the presence of a seal or the like provided in a portion that forms the second pilot pressure chamber. The “set liquid amount” described in this section can be determined based on the range, for example.

(3) The regulator is
The pressure receiving area for receiving the second pilot pressure on the other end side of the valve body is smaller than the pressure receiving area for receiving the second pilot pressure on the one end side of the pilot piston (1) or (2) The hydraulic brake system according to item.

  In the aspect described in this section, the structure of the regulator is limited. In the aspect described in this section, the force for retreating the pilot piston is stronger than the force for advancing the valve body by the second pilot pressure. Therefore, the pilot piston is separated from the valve body in a state where the force for moving the valve body forward by the second pilot pressure is smaller than the force for moving the valve body backward by the adjustment pressure, and the adjustment pressure is reduced. Become. In the hydraulic brake system described in this section, since the second pilot pressure can be quickly raised to the target hydraulic pressure by the second pilot pressure preparation control, it is possible to suppress a decrease in the adjustment pressure. is there.

(4) The regulator is
The pressure receiving area that receives the adjustment pressure on one end side of the valve body is smaller than the pressure receiving area that receives the first pilot pressure on the other end side of the pilot piston. The hydraulic brake system according to any one of the above.

  In the aspect described in this section, the structure of the regulator is limited, and the pressure receiving area on which the adjustment pressure of the valve element acts is relatively small. That is, according to the aspect described in this section, the size of the valve body can be made relatively small. For example, when the valve mechanism is a spool valve mechanism, the spool as the valve element is configured to suppress leakage of the hydraulic fluid by narrowing the clearance with respect to the one holding the spool. Therefore, according to the aspect described in this section, since the size of the valve body can be made relatively small, it is possible to sufficiently suppress the leakage of the hydraulic fluid compared to the case where the valve body is large. It is. On the other hand, since the pressure receiving area of the pilot piston that receives the first pilot pressure is relatively large, in the first state, the pilot pressure required to advance the valve body can be relatively small. .

  However, when the regulator described in this section is employed, for example, even when the same brake operation member is operated, the adjustment pressure adjusted by the first pilot pressure and the adjustment adjusted by the second pilot pressure The pressure may be different. Therefore, when switching from the first state to the second state in a state where the brake operation is performed, the adjustment pressure fluctuates. However, the second pilot pressure preparation control changes the first state to the second state. At the time of switching, it is possible to quickly obtain the adjustment pressure in the second state.

(5) When the adjustment pressure chamber provided on the other end side of the valve body is defined as a first adjustment pressure chamber,
The regulator is
A second regulating pressure chamber that communicates with the first pressure regulating chamber and into which hydraulic fluid for applying a force toward the other end of the pilot piston is introduced;
In the first state, the first adjustment pressure chamber and the first pilot pressure received by the pilot piston from one end side in a state where the other end side of the pilot piston and one end side of the valve body are in contact with each other. The hydraulic fluid in the second adjustment pressure chamber is regulated,
In the second state, the hydraulic fluid in the first adjustment pressure chamber is regulated by the second pilot pressure received by the valve body from one end side in a state where the pilot piston and the valve body are separated from each other. (4) The hydraulic brake system according to (4).

  In the aspect described in this section, in the aspect in which the pressure receiving area that receives the adjustment pressure of the valve body is reduced, the regulator is configured such that the adjustment pressure also acts on the pilot piston. That is, in the aspect described in this section, the difference between the pressure receiving area where the pilot piston and the valve body that operate integrally in the first state receive the first pilot pressure and the pressure receiving area where the adjustment pressure is received is reduced, or It can be almost eliminated. Therefore, according to the aspect described in this section, although the pressure receiving area where the regulator receives the adjustment pressure of the valve body is smaller than the pressure receiving area where the pilot piston receives the first pilot pressure, the regulator adjusts with the first pilot pressure. The difference from the pressure can be reduced, or can be made almost equal.

(6) The second pilot pressure chamber working fluid supply device includes:
A pressure-increasing control valve provided between the high-pressure source and the second pilot pressure chamber and allowing a flow of hydraulic fluid at a larger flow rate than when the supplied current is small,
The second pilot pressure preparation control is
When hydraulic fluid is once supplied to the second pilot pressure chamber in a state where the valve body and the pilot piston are in contact with each other, a first set current is supplied to the pressure increase control valve, and then the adjustment pressure Any one of the items (1) to (5) is for supplying a second set current that is larger than the first set current to the pressure increase control valve until the pressure reaches the target hydraulic pressure. Hydraulic brake system described in 1.

  In the aspect described in this section, the second pilot pressure control device includes a pressure increase control valve, and the flow rate supplied to the second pilot pressure chamber by controlling the current to the pressure increase control valve. Is configured to change. According to the aspect described in this section, the second pilot pressure preparation control can be simplified. From the viewpoint of increasing the adjustment pressure corresponding to the second pilot pressure to the target hydraulic pressure at an early stage, it is desirable that the second set current is large.

  (7) The hydraulic brake system according to item (6), wherein the second set current is set to an electric current that allows the pressure increase control valve to allow a flow of hydraulic fluid having a maximum flow rate.

  The mode described in this section is a mode in which the second set current is set to the maximum current in the mode in which the second pilot pressure preparation control is executed by controlling the supply current to the pressure increase control valve. According to the aspect described in this section, the adjustment pressure corresponding to the second pilot pressure can be raised to the target hydraulic pressure at an early stage as described above.

(8) The second pilot pressure preparation control is
The set pressure increase control valve is set for a set time so that a set amount of hydraulic fluid set so as not to separate the valve body and the pilot piston is introduced into the second pilot pressure chamber. The hydraulic brake system according to any one of (6) to (7), wherein the first set current is supplied, and then the current supplied to the pressure increase control valve is changed to the second set current.

  The mode described in this section is a mode in which the flow rate of supplying hydraulic fluid to the second pilot pressure chamber is increased on condition that the hydraulic fluid having the set fluid amount described above is introduced into the second pilot pressure chamber. This is a specific embodiment. According to the aspect of this section, when the first set current is supplied to the pressure increase control valve for a set time, it is estimated that the set amount of hydraulic fluid has been introduced into the second pilot pressure chamber, and then the second pilot pressure The flow rate of the hydraulic fluid supplied to the chamber is increased.

(9) The master cylinder is
It has a partition portion in which the interior is partitioned into two liquid chambers and an opening is formed, and includes a housing that houses the pressure piston on the front side of the partition portion and the input piston on the rear side,
The pressure piston is
It has a main body part with a ridge formed at the rear end, and a protruding part that extends rearward from the main body part and protrudes rearward from the opening of the partition part,
The input chamber of the master cylinder is
The hydraulic brake system according to any one of (1) to (8), wherein a partition is formed between a rear surface of the rod and a front surface of the partition portion on an outer periphery of the protruding portion of the pressurizing piston. .

  In the aspect described in this section, the structure of the master cylinder is limited, and the structure for defining the input chamber into which the hydraulic fluid regulated by the regulator is introduced is embodied.

(10) The master cylinder is
A pressure chamber is provided in front of the flange on the outer periphery of the main body of the pressure piston, and is provided with a counter chamber facing the input chamber with the flange interposed therebetween, and the pressure of the hydraulic fluid in the inter-piston chamber of the pressure piston is reduced. The pressure receiving area to be received is equal to the pressure receiving area to receive the pressure of the hydraulic fluid in the facing chamber in the pressurizing piston,
The hydraulic brake system
In the first state, the chamber between the pistons is shut off from the opposing chamber, and the opposing chamber is communicated with a low pressure source to depend on both the hydraulic pressure in the inter-piston chamber and the hydraulic pressure in the input chamber. To advance the pressure piston,
In the second state, the pressure piston is moved forward by relying only on the hydraulic pressure of the input chamber by communicating the inter-piston chamber with the opposing chamber. Hydraulic brake system.

  In the second state, in the second state, the force in the direction of moving the pressurizing piston forward by the hydraulic pressure in the inter-piston chamber balances the force in the direction of moving the pressurizing piston backward by the hydraulic pressure in the facing chamber. Even if the input piston moves forward by the operation of the brake operation member, the pressure piston does not move forward. That is, in the master cylinder of this section, the brake device generates a braking force whose magnitude depends on the pressure of the hydraulic fluid supplied from the regulator to the input chamber without depending on the operating force applied to the brake operating member. It is configured as follows. Therefore, the hydraulic brake system described in this section is suitable for a vehicle including a device that generates a braking force separately from the hydraulic brake system such as a hybrid vehicle.

  In the first aspect, the brake in which the brake force having a magnitude depending on the pressure of the hydraulic fluid supplied from the regulator to the master cylinder and the brake force having a magnitude depending on the operation force are added in the first state. The brake device generates a force, and in the second state, the brake device generates a brake force that depends only on the pressure of the hydraulic fluid supplied from the regulator to the master cylinder. In the aspect described in this section, in order to generate the same braking force in the first state and the second state when the operation amount of the brake operation member is constant, the hydraulic pressure of the input chamber in the second state Becomes larger than the hydraulic pressure of the input chamber in the first state. That is, when switching from the first state to the second state after the operation of the brake operation member is started, it is necessary to increase the fluid pressure in the input chamber, so the second pilot pressure preparation control is effective.

(11) The hydraulic brake system is
A communication path that connects the inter-piston chamber and the counter chamber, and is connected to a low-pressure source;
A communication switching valve that is provided on the side of the inter-piston chamber from a location where the low-pressure source in the communication path is connected, and switches between a state allowing the communication between the inter-piston chamber and the opposing chamber and a state blocking the communication; ,
A low-pressure source cutoff valve that is provided between the communication path and the low-pressure source, and switches between a state where the communication path communicates with the low-pressure source and a state where the communication path is shut off from the low-pressure source;
A stroke simulator provided on the opposite chamber side from a location where a low-pressure source is connected in the communication path,
In the first state, the communication switching valve shuts off the communication between the inter-piston chamber and the counter chamber, and the low pressure source shut-off valve communicates the counter chamber with a low pressure source.
In the second state, the communication switching valve allows communication between the inter-piston chamber and the counter chamber, and the low-pressure source cutoff valve blocks the communication path from the low-pressure source. The hydraulic brake system according to item 10).

  In the aspect described in this section, when the brake operation member is operated and in the first state, the hydraulic pressure in the inter-piston chamber is increased. And when switching to a 2nd state, the chamber between pistons is connected with the opposing chamber connected to the low pressure source, and the hydraulic pressure of the chamber between pistons falls. Since a stroke simulator is provided in the communication passage that communicates between the inter-piston chamber and the facing chamber, the brake operation member enters when a certain operation force is applied to the brake operation member. . That is, in such a case, the amount of operation of the brake operation member increases, and the amount of increase in the adjustment pressure when switching from the first state to the second state with the brake operation member being operated increases. Two pilot pressure preparation control is effective.

It is a figure showing the outline of the vehicles carrying the hydraulic brake system which is an example of the claimable invention. It is sectional drawing of the regulator shown in FIG. It is a figure which shows typically the principal part of the hydraulic brake system of an Example. In the hydraulic brake system of an Example, it is a figure for demonstrating the case where switching between a 1st state and a 2nd state is performed, these 1st state and 2nd state, the energization state of ECU, brake switch of FIG. It is a figure which shows the relationship between a state and the state of an ignition switch. (a) The general case where the driver gets into the vehicle and the ignition switch is turned on. In (b), the ignition switch is turned on for a long time after the door is switched from the closed state to the open state. (C) shows the case where the driver was not turned off and turned on again after the ignition switch was turned off. FIG. 3 is a diagram showing a relationship between the amount of hydraulic fluid introduced into a second pilot pressure chamber and the hydraulic pressure in the second pilot pressure chamber of the regulator shown in FIG. 1. It is a figure which shows the temporal change of the supply current to a pressure increase control valve, and a servo pressure until it switches from a 1st state to a 2nd state. It is a figure which compares the electric current which actually flows with respect to the target supply current to the pressure increase control valve when 2nd pilot pressure preparation control is performed compared with the case where 2nd pilot pressure preparation control is not performed. It is a figure which shows the flowchart of the servo pressure control program performed in ECU as a control apparatus shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings as modes for carrying out the claimable invention. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do. Moreover, it is also possible to constitute the modification of the following Example using the technical matter described in the description of each item of [Aspect of the Invention].

<Configuration of hydraulic brake system>
(A) Overall Configuration A vehicle hydraulic brake system that is an embodiment of the claimable invention is a hydraulic brake system that is mounted on a hybrid vehicle and uses brake oil as hydraulic fluid. As shown in FIG. 1, the present hydraulic braking system is roughly (a) provided on four wheels 10, each of which generates a braking force, and (b) as a brake operation member. The operation of the brake pedal 14 is input, and the master cylinder 16 that supplies the pressurized hydraulic fluid to each brake device 12; and (c) the anti-cylinder disposed between the master cylinder 16 and the four brake devices 12. A lock unit 18 [ABS], (d) a high-pressure source device 22 that supplies high-pressure hydraulic fluid by pumping the hydraulic fluid from a reservoir 20 that is a low-pressure source, and pressurizes the hydraulic fluid, and (e) supplied from the high-pressure source device 22 A regulator 24 that regulates the hydraulic fluid to be supplied and supplies the hydraulic fluid to the master cylinder 16, and (f) an electromagnetic pressure-increasing linear valve for adjusting the pressure of the hydraulic fluid supplied to the regulator 24 [ LA] 26 and pressure-reducing linear valve [SLR] 28, and (g) a brake electronic control unit [ECU] 30 as a control device that controls the hydraulic brake system by controlling those devices, equipment, and valves, It is comprised including. The four wheels 10 are represented as a right front wheel 10FR, a left front wheel 10FL, a right rear wheel 10RR, and a left rear wheel 10RL when it is necessary to represent left and right front and rear. Further, when it is necessary to distinguish the left and right and the front and rear, the components such as the four brake devices 12 are denoted by the same reference numerals as those of the wheels 10 and represented as 12FR, 12FL, 12RR, 12RL, and the like. Incidentally, the character of [] is a code used in the drawing.

(B) Brake device and ABS unit A brake device 12 provided corresponding to each wheel 10 is held by a disk rotor rotating with the wheel 10, a caliper held by a carrier, a wheel cylinder held by the caliper, and a caliper. This is a disc brake device that includes a brake pad that sandwiches the disc rotor by being moved by the wheel cylinder. The ABS unit 18 is a unit including a pressure increasing on / off valve, a pressure reducing on / off valve, a pump device, and the like that are provided corresponding to each wheel, and the wheel 10 is locked by a slip phenomenon or the like. This is a device that is actuated to prevent the wheel lock from lasting.

(C) Master Cylinder i) Master Cylinder Structure The master cylinder 16 is a master cylinder integrated with a stroke simulator. Generally speaking, in the housing 40, the first pressure pistons 42, which are two pressure pistons, A second pressurizing piston 44 and an input piston 46 are disposed, and a stroke simulator mechanism 48 is incorporated. In the following description of the master cylinder 16, for the sake of convenience, the left side in the figure is referred to as the front side, and the right side is referred to as the rear side. Moving to the right is called retreat.

  The housing 40 has a space in which the first pressurizing piston 42, the second pressurizing piston 44, and the input piston 46 are disposed, and the space is closed with a front end closed and an annular section. The section 50 is divided into a front chamber 52 and a rear chamber 54. The second pressurizing piston 44 has a bottomed cylindrical shape that opens forward, and is disposed on the front side in the front chamber 52. On the other hand, the first pressurizing piston 42 has a main body 58 having a bottomed cylindrical shape and a flange 56 formed at the rear end, and a protrusion 60 extending rearward from the main body 58. 58 is disposed behind the second pressurizing piston 44 in the front chamber 52. Since the partition 50 has an annular shape, an opening 62 is formed at the center, and the protrusion 60 extends through the opening 62 to the rear chamber 54. The input piston 46 is disposed in the rear chamber 54, more specifically, a part of the input piston 46 enters the interior of the rear chamber 54 from the rear, and the brake pedal 14 disposed in the rear moves the link rod 64. And is connected to the input piston 46.

  More specifically, between the first pressurizing piston 42 and the second pressurizing piston 44, two front wheels 10RR and 10RL corresponding to the two rear wheels 10RL are disposed in front of the main body 58 of the first pressurizing piston 42. The first pressurizing chamber R1 in which the hydraulic fluid supplied to the brake devices 12RR and 12RL is pressurized by the advancement of the first pressurizing piston 42 is provided on the front side of the second pressurizing piston 44 with two front wheels 10FR, A second pressurizing chamber R2 is formed in which hydraulic fluid supplied to the two brake devices 12FR and 12FL corresponding to 10FL is pressurized by the advancement of the second pressurizing piston 44, respectively. On the other hand, an inter-piston chamber R <b> 3 is formed between the first pressurizing piston 42 and the input piston 46. More specifically, the first pressurization is performed using the opening 62 so that the rear end of the protrusion 60 extending rearward from the opening 62 formed in the partition 50 faces the front end of the input piston 46. The inter-piston chamber R3 is formed so that the piston 42 and the input piston 46 face each other. Further, in the front chamber 52 of the housing 40, the front end surface of the partition 50 and the rear end surface of the main body 58 of the first pressurizing piston 42, that is, the rear end surface of the flange 56, on the outer periphery of the protrusion 60. An annular input chamber R4 into which hydraulic fluid supplied from the regulator 24 is introduced is formed so as to be partitioned. Furthermore, on the outer periphery of the main body 58, an annular facing chamber R5 that faces the input chamber R4 is formed in front of the flange 56 with the flange 56 interposed therebetween.

  The first pressurizing chamber R1 and the second pressurizing chamber R2 are respectively connected via the atmospheric pressure ports P1 and P2 when the first pressurizing piston 42 and the second pressurizing piston 44 are located at the rear end in the movement range. It is possible to communicate with the reservoir 20, and also communicate with the brake device 12 via the output ports P 3 and P 4 and the ABS unit 18, respectively. Incidentally, the first pressurizing chamber R1 is communicated with the brake devices 12RR and 12RL via a regulator 24 described later. The input chamber R4 is communicated with an adjustment pressure port of the regulator 24 described later through an input port P5.

  The inter-piston chamber R3 communicates with the communication port P6, and the counter chamber R5 communicates with the communication port P7. The communication port P6 and the communication port P7 are connected by a communication path 70 that is an external communication path. . In the middle of the communication path 70, there is provided a normally closed electromagnetic open / close valve 72, that is, an open / close valve 72 that is closed when not excited and opened when excited. When the valve is opened, the inter-piston chamber R3 and the counter chamber R5 are communicated with each other. In a state where the inter-piston chamber R3 and the counter chamber R5 communicate with each other, it can be considered that one liquid chamber, that is, a liquid chamber that can be called a reaction force chamber R6 is formed. The on-off valve 72 has a function of switching between communication and non-communication between the inter-piston chamber R3 and the counter chamber R5, and is hereinafter referred to as a “communication switching valve 72”.

  The master cylinder 16 is further provided with two atmospheric pressure ports P8 and P9, which communicate with each other through an internal passage. One atmospheric pressure port P8 is connected to the reservoir 20, and the other atmospheric pressure port P9 is connected to the communication passage 70 between the communication switching valve 72 and the facing chamber R5 via a low pressure passage 74 that is an external communication passage. It is connected to. The low-pressure passage 74 is provided with a normally-open electromagnetic open / close valve 76, that is, an open / close valve 76 that is opened when de-energized and closed when excited. Since this on-off valve 76 has a function of blocking the communication between the facing chamber R5 and the reservoir 20, it is hereinafter referred to as a “low pressure source cutoff valve 76”.

The housing 40 has a space different from the space where the first pressure piston 42, the second pressure piston 44, and the input piston 46 are disposed. The stroke simulator mechanism 48 includes the space, A reaction force piston 80 disposed in the space and two reaction force springs 82 and 84 (both are compression coil springs) that urge the reaction force piston 80 are configured. A buffer chamber R7 is formed on the rear side of the reaction force piston 80 (represented as a substantially crushed space in the figure). When the input piston 46 moves forward by the operation of the brake pedal 14, the working fluid in the facing chamber R5, that is, the working fluid in the reaction force chamber R6 is introduced into the buffer chamber R7 via the internal passage. An operation reaction force is applied to the brake pedal 14 by the elastic reaction force of the reaction force springs 82 and 84 corresponding to the amount of hydraulic fluid, that is, the advance amount of the input piston 46 acting on the reaction force chamber R6. Further, in the present system, the communication path 70 detects the pressure of the hydraulic fluid in the reaction force chamber R6 (hereinafter sometimes referred to as “reaction force pressure P _RCT ”), that is, the reaction force against the brake pedal 14 ( A reaction force pressure sensor [P _RCT ] 86 for detecting the operation force applied to the brake pedal 12) is provided.

ii) Function of the master cylinder In the normal state, the communication switching valve 72 is open, and the low-pressure source shut-off valve 76 is closed. The reaction force is generated by the inter-piston chamber R3 and the counter chamber R5. A chamber R6 is formed. In the master cylinder 16, the pressure receiving area of the first pressurizing piston 42 against which the pressure of the hydraulic fluid in the inter-piston chamber R3 acts to move the first pressurizing piston 42 forward, that is, the inter-piston chamber pressure receiving area, that is, The area of the rear end surface of the projecting portion 60 of the first pressure piston 42 and the pressure receiving area of the first pressure piston 42 on which the pressure of the hydraulic fluid in the facing chamber R5 acts to move the first pressure piston 42 rearward ( (Opposite chamber pressure receiving area), that is, the area of the front end face of the flange 56 of the first pressurizing piston 42 is made equal. Therefore, even if the brake pedal 14 is operated to advance the input piston 46, the first pressurizing piston 42 and the second pressurizing piston 44 do not advance depending on the operating force, that is, the pressure in the reaction force chamber R6. The hydraulic fluid pressurized by the master cylinder 16 is not supplied to the brake device 12. On the other hand, when the pressure of the hydraulic fluid from the high pressure source device 22 is introduced into the input chamber R4, the first pressure piston 42 and the second pressure piston 44 move forward depending on the pressure of the hydraulic fluid, The hydraulic fluid pressurized to the pressure corresponding to the pressure of the hydraulic fluid in the input chamber R4 is supplied to the brake device 12. That is, according to the master cylinder 16, in the normal state (normal time), the pressure of the hydraulic fluid supplied from the high pressure source device 22 to the master cylinder 16 without depending on the operating force applied to the brake pedal 14, that is, The brake device 12 generates a braking force having a magnitude depending on the pressure of the hydraulic fluid supplied from the regulator 24 to the master cylinder 16.

  A vehicle equipped with this system is a hybrid vehicle as described above, and the regenerative braking force can be used in the vehicle. Therefore, the brake device 12 may generate a braking force that is obtained by subtracting the regenerative braking force from the braking force determined based on the brake operation. In this system, since the high pressure source pressure dependent braking force generation state is realized, the brake device 12 can generate a braking force that does not depend on the brake operation force. From such an action, this system is a hydraulic brake system suitable for a hybrid vehicle.

On the other hand, the communication switching valve 72 and the low-pressure source shut-off valve 76 are not energized at the time of electrical failure or at the time of rapid start described in detail later. The valve 76 is opened, the inter-piston chamber R3 is sealed, and the opposing chamber R5 is opened to atmospheric pressure. In this state, the operating force applied to the brake pedal 14 is transmitted to the first pressurizing piston 42 via the hydraulic fluid in the inter-piston chamber R3, and the first pressurizing piston 42 and the second pressurizing piston 44 move forward. To do. That is, the brake device 12 generates a braking force having a magnitude depending on the operating force applied to the brake pedal 14. Note that when the hydraulic fluid regulated by the master pressure P _MST is introduced from the regulator 24 into the input chamber R4, the first pressurizing piston 42 and the second pressurizing piston 44 are supplied from the regulator 24 to the master cylinder 16. The hydraulic fluid is advanced by both the hydraulic fluid pressure and the operating force, and the braking force depends on both of them, that is, the hydraulic fluid supplied to the master cylinder 16 from the regulator 24 has a magnitude depending on the pressure. The brake device 12 generates a braking force obtained by adding the braking force and the braking force having a magnitude depending on the operation force.

(D) High-pressure source device The high-pressure source device 22 stores the pump 90 that pumps the hydraulic fluid from the reservoir 20, the pump motor 92 that drives the pump 90, and the hydraulic fluid discharged from the pump 90 in a pressurized state. And an accumulator [ACC] 94. The pump motor 92 has a pressure of the hydraulic fluid stored in the accumulator 94 (hereinafter sometimes referred to as “high pressure source pressure P _ACC ”, so-called “accumulator pressure”) as a high pressure source pressure sensor [P _ACC ]. Based on the 96 detection values, control is performed so as to be within a predetermined range.

(E) Regulator i) Regulator structure The regulator 24 is a pilot-type pressure control valve that operates mechanically in accordance with the hydraulic pressure (pilot pressure) of the hydraulic fluid supplied to the regulator 24, and in accordance with the pilot pressure. The hydraulic pressure of the high-pressure source device 22 is adjusted, and the adjusted hydraulic fluid is supplied to the input chamber R4 of the master cylinder 16.

  The structure of the regulator 24 will be described in detail with reference to FIG. The regulator 24 roughly includes a housing 100 and a spool valve mechanism 102 and a pilot piston 104 provided in the housing 100. In the drawing, the central axis extending in the left-right direction is the axis of the regulator 24, specifically, the axis of the housing 100, and the right side in the axial direction is called one end side and the left side is called the other end side. Further, in the movement direction of the pilot piston 104 or the like, movement toward one end side may be referred to as advance, and movement toward the other end side may be referred to as retreat.

  The spool valve mechanism 102 includes a spool 110 and a spool holding cylinder 112 that slidably holds the spool 110. The spool holding cylinder 112 is fitted into the housing 100 and is fixed to one end side of the housing 100. That is, it can be considered that the housing includes the spool holding cylinder 112.

  On one end side of the spool 110, an adjustment pressure chamber R8 is defined by the spool holding cylinder 112 and the housing 100. When the spool 110 is at the moving end on the other end side, the spool valve mechanism 102 communicates the reservoir 20 and the adjustment pressure chamber R8 and blocks communication between the high pressure source device 22 and the adjustment pressure chamber R8. The movement of the spool 110 toward one end blocks the communication between the reservoir 20 and the adjustment pressure chamber R8, and also connects the high pressure source device 22 and the adjustment pressure chamber R8. Hereinafter, the configuration of the spool valve mechanism 102 will be described in detail.

  The spool 110 extends from the other end side of the spool holding cylinder 112 and is moved toward the other end side by a separation spring 114 which is a compression coil spring disposed between the spool 110 and the spool holding cylinder 112. It is energized. A pilot piston 104 is disposed on the other end side of the spool 110, and the pilot piston 104 is also biased toward the other end side by a separation spring 116. The position where the spool 110 is in contact with the pilot piston 104 that is in contact with the other end of the housing 110 is the moving end on the other end side in the movable range. When the spool 110 is in that position, the adjustment pressure chamber R8 is connected to the master cylinder 16 in the reservoir 20 via the internal port 118 formed in the spool holding cylinder 112, the internal passage 120 formed in the housing 100, and the like. It communicates with the atmospheric pressure port P10 communicated via.

  In the housing 100, in addition to the atmospheric pressure port P10, the high pressure port P11 to which the hydraulic fluid is supplied from the high pressure source device 22 and the hydraulic fluid adjusted in the adjustment pressure chamber R8 are supplied to the input chamber R4 of the master cylinder 16. An adjustment pressure port P12 for supply is provided. The spool holding cylinder 112 is formed with internal ports 122 and 124 for communicating with the ports P11 and P12. The internal port 124 for communicating with the adjustment pressure port P12 communicates with the adjustment pressure chamber R8 via the internal passage and the adjustment pressure chamber R8. When the spool 110 is at the moving end on the other end side, the internal port 124 for communicating with the adjustment pressure port P12 is blocked by the outer peripheral surface of the spool 110, and the adjustment pressure chamber R8 and the high pressure source device Communication with 22 is cut off.

  Then, when the spool 110 moves to one end side, the two internal ports 122 and 124 are communicated with each other by a recess formed on the outer peripheral surface of the spool 110. That is, the adjustment pressure chamber R8 and the high pressure source device 22 are communicated with each other. In this case, the internal port 118 for communicating with the atmospheric pressure port P10 is blocked by the outer peripheral surface of the spool 110, and the communication between the adjustment pressure chamber R8 and the reservoir 20 is blocked.

A first pilot pressure chamber R <b> 9 is defined by the housing 100 at the other end side of the pilot piston 104. The first pilot pressure chamber R9 communicates with the first pilot pressure ports P13 and P14 formed in the housing 100 by an internal passage, and as can be seen from FIG. 1, the first pilot pressure ports P13 and P14 The first cylinder 17 communicates with the first pressurizing chamber R1 of the master cylinder 16 and the brake devices 12RL and 12RR for the rear wheels through the respective parts. Therefore, the first pilot pressure chamber R9 is a part of the hydraulic fluid supply path from the master cylinder 16 to the brake devices 12RL and 12RR. That is, in the first pilot pressure chamber R9, hydraulic fluid supplied from the master cylinder 16 to the brake devices 12RL and 12RR corresponding to the wheels 10RL and 10RR on the rear wheel side, that is, hydraulic fluid of the master pressure P _MST is stored in the first pilot pressure chamber R9. 1 pilot pressure P _PLT1 is introduced as hydraulic fluid. Accordingly, the pilot piston 104 is configured to advance together with the spool 110 by the action of the hydraulic fluid in the first pilot pressure chamber R9, that is, the action of the first pilot pressure P _PLT1 .

The pilot piston 104 has a bottomed hole 130 on one end side. On the other hand, the other end side of the spool holding cylinder 112 is a small outer diameter portion 132 having a smaller outer diameter than the one end side. The outer diameter of the small outer diameter portion 130 is substantially the same size as the diameter of the bottomed hole 130, and the small outer diameter portion 132 of the spool holding cylinder 112 enters the inside of the bottomed hole 130. It has become. A second pilot pressure chamber R10 is defined between the pilot piston 104 and the spool 110, specifically, the bottomed hole 130 of the pilot piston 104 and the surface on the other end side of the spool 110 and the spool holding cylinder 112. Has been. The second pilot pressure chamber R10 communicates with second pilot pressure ports P15 and P16 formed in the housing 100, and through each of the second pilot pressure ports P15 and P16, the pressure increasing linear valve 26, The pressure reducing linear valve 28 is in communication. Therefore, the hydraulic fluid whose pressure is adjusted by the pressure increasing linear valve 26 and the pressure reducing linear valve 28 is introduced into the second pilot pressure chamber R10 as the hydraulic fluid of the second pilot pressure P _PLT2 . Therefore, the spool 110 is configured to advance by the action of the pressure of the hydraulic fluid in the second pilot pressure chamber R10, that is, the second pilot pressure P _PLT2 .

In addition, a buffer piston 140 is slidably held in the pilot piston 104 in the axial direction. The buffer piston 140 is elastically supported by a buffer spring 142 which is a compression coil spring. The space on the front end side (one end side) of the buffer piston 140 is in _{communication} with the second pilot pressure chamber R10, and has a function of suppressing pressure vibration generated in the second pilot pressure P _PLT2 . Incidentally, the internal space of the pilot piston 104 provided with the buffer piston 140 communicates with the atmospheric pressure port P10, and the hydraulic pressure of the hydraulic fluid is always atmospheric pressure.

On the outer peripheral side of the small outer diameter portion 132 of the spool holding cylinder 112, another adjustment pressure chamber R11 communicating with the adjustment pressure chamber R8 is defined by the pilot piston 104 and the housing 100. That is, the pilot piston 104 is given a force toward the other end side by the hydraulic pressure of the hydraulic fluid in the adjustment pressure chamber R11. In the following description, the adjustment pressure chamber R8 provided on one end side of the spool 110 is referred to as the first adjustment pressure chamber R8, and the adjustment pressure chamber R11 provided on one end side of the pilot piston 104 is referred to as the second adjustment pressure chamber R11. I will call it. In order to connect the adjusted pressure chambers R8, R11 and the input chamber R4, the servo passage 150, which is a liquid passage connecting the adjusted pressure port P12 and the input port P5, is regulated by the regulator 24 and is input to the input chamber R4. Is provided with a servo pressure sensor [P _SRV ] 152 for detecting a servo pressure P _SRV that is a hydraulic pressure of the hydraulic fluid supplied to the hydraulic pressure.

Further, the housing 100 is provided with another high-pressure port P17 communicating with the high-pressure port P11 through an internal passage. As can be seen from FIG. 1, the high-pressure port P17 is connected to the pressure-increasing linear valve 26 and the relief valve 154. Communicate. Further, the housing 100 is provided with another atmospheric pressure port P18 that communicates with the atmospheric pressure port P10 through an internal passage. As can be seen from FIG. 1, this atmospheric pressure port P18 communicates with the relief valve 154. ing. Therefore, the hydraulic fluid of the high-pressure source pressure P _ACC from the high-pressure source device 22 is supplied to the pressure-increasing linear valve 26 via the regulator 24, and when the high-pressure source pressure P _ACC becomes higher than the set pressure, The hydraulic fluid from the source device 22 is allowed to flow to the reservoir 20 via the regulator 24.

ii) Function of regulator In this regulator 24, when the second pilot pressure P _PLT2 that is the pressure of the hydraulic fluid in the second pilot pressure chamber R10 is increased by the pressure increasing linear valve 26 and the pressure reducing linear valve 28, the spool 110 is _urged by the second pilot pressure P _PLT2 and moves from the moving end on the other end side to the one end side. By this movement, the spool valve mechanism 102 causes the high pressure source device 22 and the adjustment pressure chambers R8 and R11 to communicate with each other, so that the pressure of the hydraulic fluid supplied to the input chamber R4 of the master cylinder 16, that is, the servo pressure _PSRV is increased. Raised. On the other hand, as the servo pressure P _SRV increases, the pressure of the hydraulic fluid in the adjustment pressure chamber R8 also increases, and the spool 110 is _biased by the servo pressure P _SRV . That is, the force to advance the spool 110 by the second pilot pressure P _PLT2, the force to retract the spool 110 is maintained a state of balance by the servo pressure P _SRV, at a pressure of hydraulic fluid supplied to the master cylinder 16 A certain servo pressure P _SRV is _adjusted to a magnitude corresponding to the second pilot pressure P _PLT2 (second state). The pressure receiving area for receiving the hydraulic pressure (second pilot pressure P _PLT2 ) of the second pilot pressure chamber R10 of the spool 110 and the pressure receiving area for receiving the hydraulic pressure (servo pressure P _SRV ) of the first adjusting pressure chamber R8 of the spool 110. And the servo pressure P _SRV is _regulated to substantially the same magnitude as the second pilot pressure P _PLT2 (strictly speaking, the servo pressure P _SRV is _greater than the second pilot pressure P _PLT2 . Slightly smaller).

Incidentally, the hydraulic fluid of the master pressure P _MST is introduced into the first pilot pressure chamber R9 as the hydraulic fluid of the first pilot pressure P _PLT1 , but the master cylinder 16 has a pressure increase ratio, that is, the master pressure relative to the servo pressure P _SRV . The ratio of the pressure P _MST is approximately 1. Then, the pilot piston 104 has a hydraulic force (first pilot pressure P _PLT1 = master pressure P _MST ) in the first pilot pressure chamber R9 and a hydraulic pressure (second pilot) in the second pilot pressure chamber R10. The force of the reversing direction by the pressure P _PLT2 ) and the force of the retreating direction by the hydraulic pressure (servo pressure P _SRV ) of the second adjustment pressure chamber R11 are applied. In the regulator 24, the force in the backward direction is larger than the forward force. Therefore, when the pilot piston 104 does not move forward and the pressure is _regulated by the second pilot pressure P _PLT2 , the first pilot pressure P _{PLT1 is used.} The force based on the above is not applied to the spool 110.

On the other hand, pressure _regulation by the first pilot pressure P _PLT1 is performed at the time of electrical failure or rapid start. In this case, the second pilot pressure chamber R10 is open to atmospheric pressure. When the master pressure P _MST, which is the pressure of the hydraulic fluid introduced as the hydraulic fluid of the first pilot pressure P _PLT1 , increases, the pilot piston 104 is advanced and the spool 110 is in contact with the spool 110. Along with this, the spool 110 moves from the moving end on the other end side to the one end side. By this movement, the spool valve mechanism 102 causes the high pressure source device 22 and the adjustment pressure chambers R8 and R11 to communicate with each other, so that the pressure of the hydraulic fluid supplied to the input chamber R4 of the master cylinder 16, that is, the servo pressure _PSRV is increased. Raised. On the other hand, as the servo pressure _PSRV increases, the pressure of the hydraulic fluid in the first adjustment pressure chamber R8 and the pressure of the hydraulic fluid in the second adjustment pressure chamber R11 also increase, and the pilot piston 104 and the spool 110 _Powered by _PSRV . That is, a state is maintained in which the force that advances the pilot piston 104 and the spool 110 by the first pilot pressure P _PLT2 and the force that moves the pilot piston 104 and the spool 110 backward by the servo pressure P _SRV are maintained. is the pressure of the hydraulic fluid supplied servo pressure P _SRV is pressure adjusted to a size corresponding to the first pilot pressure P _PLT1 (first state).

The spool 110 has a relatively small outer diameter in order to suppress the leakage of hydraulic fluid by narrowing the clearance with respect to the spool holding cylinder 112. On the other hand, the outer diameter of the pilot piston 104 is made larger by the outer diameter of the spool 110. That is, the pressure receiving area A _{P_r} receiving a first pilot pressure P _PLT1 the other end side of the pilot piston 104 is what is larger than the pressure receiving area A _SP which receives servo pressure P _SRV spool 110. Therefore, the master pressure for operating the pilot piston 104 does not increase. On the other hand, the pressure receiving area A _{P_r} that receives the first pilot pressure P _PLT1 on the other end side of the pilot piston 104 is the pressure receiving area A _SP that receives the hydraulic pressure (servo pressure P _SRV ) of the first adjustment pressure chamber R8 of the spool 110. The sum of the pressure receiving area A _{P_f1} that receives the hydraulic pressure (servo pressure P _SRV ) of the second adjustment pressure chamber R11 on one end side of the pilot piston 104 is substantially equal to the servo pressure P _SRV . The pressure is _regulated to be approximately the same as the pilot pressure P _PLT2 (strictly speaking, the servo pressure P _SRV is slightly smaller than the first pilot pressure P _PLT2 ).

f) Pressure-increasing linear valve and pressure-reducing linear valve The pressure-increasing linear valve 26 and the pressure-reducing linear valve 28 are general electromagnetic linear valves, and the illustration of the structure is omitted. The pressure-increasing linear valve 26 is a normally-closed electromagnetic linear valve disposed between the high-pressure source device 22 and the regulator 24, and the degree of opening (for example, closed) increases as the exciting current supplied to the coil increases. The ease of transition from the valve state to the valve opening state) increases, and the valve opening pressure increases. Note that when the differential pressure before and after the pressure increase linear valve 26 is constant, the flow rate increases if the supply current is increased. On the other hand, the pressure-reducing linear valve 28 is a normally open electromagnetic linear valve disposed between the regulator 24 and the reservoir 20 as a low-pressure source. For example, the ease of transition from the valve closing state to the valve opening state) decreases, and the valve opening pressure increases.

More specifically, the pressure-increasing linear valve 26 and the pressure-reducing linear valve 28 are arranged in series with the regulator 24 interposed therebetween, more specifically, the second pilot pressure chamber R10 of the regulator 24. By controlling the excitation current supplied to each of the linear valves 28, the pressure of the hydraulic fluid in the second pilot pressure chamber R10 can be controlled. According to such functions of the pressure-increasing linear valve 26 and the pressure-reducing linear valve 28, this system includes the pressure-increasing linear valve 26 and the pressure-reducing linear valve 28, and supplies hydraulic fluid to the second pilot pressure chamber R10. _Thus , it can be considered that the second pilot pressure chamber working hydraulic pressure supply device for generating the second pilot pressure P _PLT2 is configured.

g) Control system The control of this system, that is, the brake control is performed by the brake ECU 30. The brake ECU 30 roughly controls the high-pressure source device 22 (specifically, the motor 92 included therein), and controls the pressure-increasing linear valve 26 and the pressure-reducing linear valve 28. The brake ECU 30 includes a computer that is a central element, and drive circuits (drivers) for driving the motor 92, the pressure-increasing linear valve 26, the pressure-decreasing linear valve 28, and the like of the high-pressure source device 22, respectively. Yes.

The brake ECU 30 obtains the reaction force pressure P _RCT , the high pressure source pressure P _ACC , and the servo pressure P _SRV as information necessary for control, so that the reaction force pressure sensor 86, the high pressure source pressure sensor 96, the servo pressure sensor described above are acquired. 152 is connected. Further, in this system, a brake operation amount sensor [δ _PDL ] 160 for detecting the operation amount of the brake pedal 14, a brake switch [SW _BR ] 162 for detecting whether or not the brake pedal 14 is depressed, A door opening / closing switch [SW _DR ] 164, an ignition switch [SW _IG ] 166, and the like for detecting the opening / closing state of the seat side door are connected. Incidentally, the brake switch 162 is turned OFF when the operation amount of the brake pedal 14 is smaller than the set amount, and is turned ON when the operation amount becomes equal to or larger than the set amount. The door opening / closing switch 164 is turned off when the door is in the closed state and turned on when the door is in the opened state. Further, the ignition switch 166 is allowed to be switched from OFF to ON by turning on the door opening / closing switch 164 or turning on the brake switch 162. And control by brake ECU30 in this system is performed based on detection values of various sensors mentioned here.

<Operation of hydraulic brake system>
(A) Normal operation and control (second state)
In a vehicle equipped with the hydraulic brake system, the brake operation amount acquired based on the detection value of the brake operation amount sensor 160, the brake operation force acquired based on the detection value of the reaction force pressure sensor, and Based on at least one of the above, the required brake force, which is the required brake force, is calculated, and the required brake force is determined by subtracting the regenerative brake force generated by the regenerative brake system from the required brake force Is done. The hydraulic brake system operates to generate this required hydraulic brake force.

First, regarding the operation of the master cylinder 16, in the normal state, as described above, the ECU 30 excites the communication switching valve 72 and the low pressure source cutoff valve 76, opens the communication switching valve 72, The source shutoff valve 76 is closed. In addition, the principal part of this hydraulic brake system is typically shown in FIG. Then, the pressure of the hydraulic fluid from the regulator 24 is introduced into the input chamber R4, the first pressurizing piston 42 and the second pressurizing piston 44 are moved forward depending on the pressure of the hydraulic fluid, and the operation of the input chamber R4 is performed. A hydraulic fluid pressurized to a pressure corresponding to the pressure of the fluid (a hydraulic fluid having a master pressure P _MST ) is supplied to the brake device 12. That is, in the normal state, ECU 30, in order to generate the required hydraulic braking force described above, the input chamber R4 hydraulic, that is, is to control the servo pressure P _SRV. That is, the ECU 30 controls the servo pressure P _SRV by controlling the second pilot pressure P _PLT2 of the regulator 24 and adjusting the hydraulic pressure in the adjustment pressure chamber R8 to a magnitude corresponding to the second pilot pressure P _PLT2. The second state is realized.

The ECU 30 determines the target servo pressure P _SRV ^* based on the necessary hydraulic brake force, and sets the target servo pressure P _SRV so that the actual servo pressure P _SRV acquired based on the detection value of the servo pressure sensor 152 becomes the target servo pressure. Feedback control is performed based on a deviation ΔP _SRV between the servo pressure P _SRV ^* and the actual servo pressure P _SRV . Specifically, the deviation [Delta] P _SRV is, when greater than increase pressure threshold [Delta] P ₊ is a pressure increasing mode, vacuum threshold [Delta] P _- is the pressure decrease mode if smaller, vacuum threshold [Delta] P _- more and increase pressure threshold [Delta] P If it is ₊ or less, the holding mode is set.

In the pressure increasing mode, the pressure reducing linear valve 28 is closed, and the hydraulic fluid is supplied to the second pilot pressure chamber R10 by the control of the pressure increasing linear valve 26, and the second pilot pressure P _PLT2 is increased. The supply current I _SLA to the pressure-increasing linear valve 26 is determined according to the following equation based on the valve opening current I _SLA-OPEN corresponding to the differential pressure before and after and the deviation ΔP _SRV .
I _SLA = I _SLA-OPEN + K _SLA · ΔP _SRV K _SLA : Control gain The differential pressure before and after is, for example, the detected value of the high pressure source pressure sensor 96 and the second pilot pressure chamber pressure P _PLT2 (actual servo pressure P _SRV ) and it can be calculated from the difference between the valve opening current I _SLA-OPEN can be so obtained from the map data showing the relationship between the differential pressure and the valve opening current I _SLA-OPEN.

In the pressure reducing mode, the pressure increasing linear valve 26 is closed, and the second pilot pressure P _PLT2 is decreased by the control of the pressure reducing linear valve 28. The supply current I _SLR of the pressure reducing linear valve 28 is determined according to the following equation based on the valve opening current I _SLR-OPEN corresponding to the differential pressure before and after and the deviation ΔP _SRV .
I _SLR = I _SLR-OPEN -K _SLR・ ΔP _SRV K _SLR : Control gain

In the holding mode, the pressure increasing linear valve 26 and the pressure reducing linear valve 28 are closed, and the second pilot pressure P _PLT2 is maintained. The supply current to the pressure-increasing linear valve 26 and the pressure-reducing linear valve 28 at that time is in a closed state even when a differential pressure acting force is applied when the second pilot pressure reaches a magnitude corresponding to the target servo pressure. The size is such that it can be held. Incidentally, the same applies to the supply current to the pressure-reducing linear valve 28 in the pressure-increasing mode and to the pressure-increasing linear valve 26 in the pressure-reducing mode.

(B) Operation at the time of failure (first state)
On the other hand, at the time of electrical failure, control by ECU30 is not performed. That is, the communication switching valve 72 and the low pressure source cutoff valve 76 are not excited, the communication switching valve 72 is closed, and the low pressure source cutoff valve 76 is opened. That is, the operating force applied to the brake pedal 14 is transmitted to the first pressurizing piston 42 via the hydraulic fluid in the inter-piston chamber R3, and the braking force having a magnitude depending on the operating force applied to the brake pedal 14 is obtained. Is generated by the brake device 12. In addition, the hydraulic fluid pressurized depending on the brake operation force is supplied from the output port P3. The pressurized hydraulic fluid is introduced into the first pilot pressure chamber R9 of the regulator 24, so that the regulator 24 performs pressure _{regulation using} the first pilot pressure P _PLT1 (master pressure P _MST ). State), as long as the high-pressure hydraulic fluid remains in the accumulator 94, the hydraulic fluid of the servo pressure _PSRV corresponding to the master pressure _MST is supplied from the regulator 24 to the input chamber R4 of the master cylinder 16. With this supply, a brake force having a magnitude depending on both the brake operation force and the pressure of the hydraulic fluid supplied from the high pressure source device 22 and regulated by the regulator 24 is generated in the brake device 12 of each wheel 10. Will be. Incidentally, after the high-pressure hydraulic fluid no longer remains in the accumulator 94, the brake device 12 of each wheel 10 generates a braking force depending on the brake operation force.

(C) Switching between the first state and the second state in the normal state In the present vehicle, when the hydraulic brake system is normal, the vehicle enters the first state when the ignition switch 166 is OFF. Yes, when it is ON, it is in the second state. However, when the ECU 30 is energized while satisfying the conditions described later, preparation for execution of the ECU 30 such as program reading and initial check is performed, and after the preparation is completed, the first state is changed to the second state. A switching command for switching is issued. Then, in order to open the communication switching valve 72 and close the low pressure source cutoff valve 76, current is supplied to the communication switching valve 72 and the low pressure source cutoff valve 76, and control of the fluid pressure in the input chamber R4 is started. Is done. That is, from the start of energization to the ECU 30 until the communication switching valve 72 is actually opened and the low-pressure source cutoff valve 76 is closed and hydraulic pressure control (feedback control) to the input chamber R4 is started. It is considered that it is not in the second state.

  Further, as shown in FIG. 4A, in the state where the ignition switch 166 is OFF, energization to the ECU 30 is started on the condition that the door opening / closing switch 164 is switched from OFF to ON. Then, as described above, after the preparation for execution of the ECU 30 is completed, the first state is switched to the second state. It should be noted that a preparation time Ts is normally required from when the ECU 30 is energized until the ECU 30 is switched to the second state. Usually, the driver opens the door on the driver's seat and gets on, depresses the brake pedal 14, and turns on the ignition switch 166. The preparation time Ts is shorter than a general time from when the driver opens the door until the driver depresses the brake pedal 14. That is, after entering the second state, the brake pedal 14 is depressed, and then the ignition switch 166 is turned on.

  On the other hand, as shown in FIG. 4B, even if the door on the driver's seat side is switched from the closed state to the open state and energization to the ECU 30 is started and switched to the second state, it is set. If the ignition switch 166 is not turned on before the reset time Tf elapses, the ECU 30 is turned off and returned to the first state. For example, the case where the driver does not get on immediately even when the door on the driver's seat side is opened, or the case where the ignition switch 166 is not immediately turned on even if the driver gets on the vehicle. In such a case, on the condition that the brake switch 162 is switched from OFF to ON, energization to the ECU 30 is started, and a switching command from the first state to the second state is issued (rapid start). ).

  Also, as shown in FIG. 4C, when the reset time Tf elapses after the ignition switch 166 is switched from ON to OFF, the ECU 30 is deenergized and returned to the first state. Thereafter, there is a case where the reset time Tf or more passes without the driver getting off and the vehicle is started again. In such a case, the brake switch 162 is switched from OFF to ON. As a result, energization of the ECU 30 is started, and a command for switching from the first state to the second state is issued.

Consider the case of switching from the first state to the second state at the rapid start shown in FIGS. 4B and 4C, that is, in a state where the brake pedal 14 is depressed. First, the operating force applied to the brake pedal 14 when the ECU 30 is de-energized, that is, when the brake pedal 14 is depressed while the communication switching valve 72 is closed and the low pressure source cutoff valve 76 is opened. The brake device 12 generates a braking force having a magnitude depending on the braking force. In addition, since energization to the ECU 30 is started on the condition that the brake pedal 14 is depressed, the high pressure source device 22 is activated and high pressure hydraulic fluid is supplied to the regulator 24. That is, the hydraulic fluid pressurized depending on the brake operation force is introduced into the first pilot pressure chamber R9 of the regulator 24, and the regulator 24 regulates the pressure by the first pilot pressure P _PLT1 (master pressure P _MST ). Done. Then, the hydraulic fluid of the servo pressure _PSRV corresponding to the master pressure _MST is supplied from the regulator 24 to the input chamber R4 of the master cylinder 16. With this supply, a braking force having a magnitude depending on both the brake operation force and the pressure of the hydraulic fluid regulated by the regulator 24 is generated in the brake device 12 of each wheel 10. In this hydraulic brake system, when a switching command is issued, the ECU 30 immediately excites the communication switching valve 72 and the low-pressure source cutoff valve 76 so that the communication switching valve 72 is opened, and the low-pressure source cutoff valve. 76 is closed.

  Next, the first state is switched to the second state, and a brake force having a magnitude depending on both the brake operation force and the pressure of the hydraulic fluid regulated by the regulator 24 has already been generated. Therefore, a problem arises when a brake force having a magnitude depending only on the pressure of the hydraulic fluid regulated by the regulator 24 is generated.

In the regulator 24, the hydraulic pressure adjustment chamber R8, R11, that is, the servo pressure P _SRV is adjusted to the size of the master pressure P _MST to the first pilot chamber R9 are corresponding to the master pressure P _MST is introduced Although the pressure is increased, the hydraulic pressure in the second pilot pressure chamber R10, which has been released to atmospheric pressure, is increased to correspond to the hydraulic pressure in the second pilot pressure chamber R10, that is, the second pilot pressure P _PLT2 It is necessary to. In the hydraulic brake system, the servo pressure P _SRV in the second state is greater than the servo pressure P _SRV in the first state with respect to the operation amount of the brake pedal 14. Therefore, the servo pressure _PSRV becomes insufficient when switching from the first state to the second state. The present regulator 24, the area A _{P_f2} receiving a second pilot pressure P _PLT2 one end side of the pilot piston 104, is larger than the pressure receiving area A _SP which receives the second pilot pressure P _PLT2 the other end side of the spool 110 Yes. For that reason, we raise the second pilot pressure P _PLT2, orientation force the direction of advancing the spool 110, before commensurate with the direction of the force to retract the spool 100 by the servo pressure P _SRV, the pilot piston 104 retracts Exceeds the force in the direction in which the pilot piston 104 is advanced by the master pressure P _MST , and the pilot piston 104 starts to move backward. At the same time, the spool 110 moves backward. That is, in the regulator 24, the servo pressure _PSRV decreases due to the retraction of the spool 110.

  Further, as shown in FIG. 5, the regulator 24 has a second pilot pressure chamber R2 due to the presence of a seal portion between the pilot piston 104, the spool 110, and the spool holding cylinder 112 that defines the second pilot pressure chamber R10. There is a problem that even if hydraulic fluid is supplied to R10, the hydraulic pressure in the second pilot pressure chamber R10 does not rise immediately. That is, in the present hydraulic brake system configured as described above, when the feedback control described above is immediately executed when switching from the first state to the second state, the second time is controlled with respect to the control start time. There is a possibility that the time when the pilot pressure actually reaches the magnitude corresponding to the target servo pressure is delayed.

(D) Second Pilot Pressure Preparation Control Therefore, in the present hydraulic brake system, the second pilot pressure preparation control is executed in order to suppress the response delay before starting the feedback control in the second state. It has become. In the second pilot pressure preparation control, first, the working fluid is temporarily supplied to the second pilot pressure chamber R10 while the spool 110 and the pilot piston 104 are in contact with each other. up is separated by servo pressure P _SRV reaches the target servo pressure P _SRV ^*, with greater rate than the flow rate at the time of supplying the working fluid being in contact with the spool 110 and the pilot piston 104, the second pilot pressure It is control which supplies a hydraulic fluid to chamber R10. In short, in the second pilot pressure preparation control, the hydraulic fluid is supplied to the second pilot pressure chamber R10 relatively slowly until the spool 110 and the pilot piston 104 are separated from each other, and then the servo pressure P _SRV is set to the target. In this control, the hydraulic pressure in the second pilot pressure chamber R10 is quickly increased until the servo pressure P _SRV ^* is reached.

Specifically, first, the hydraulic fluid having a volume C ₀ (volume) set so as not to be separated from the spool 110 and the pilot piston 104 is relatively slowly supplied to the second pilot pressure chamber R10. The hydraulic fluid is supplied. Specifically, as shown in FIG. 6, when the ECU 30 receives a switching command from the first state to the second state, the ECU 30 applies the first set current I ₁ to the pressure-increasing linear valve 26 only during the set time T _1. It comes to supply. Then, the ECU 30 changes the supply current I _SLA to the pressure-increasing linear valve 26 from the first set current I _SLA1 to the second set current I _SLA2 after the set time T ₁ has elapsed. The second set current I _SLA2 is a current that fully _opens the opening of the pressure-increasing linear valve 26, that is, a current I _SLA-MAX that allows the flow of the hydraulic fluid having the largest flow rate. The first set current I ₁ is smaller than the second set current I ₂ . Incidentally, even if the second pilot pressure P _PLT2 reaches a magnitude corresponding to the target servo pressure, the current I _SLR0 is supplied to the pressure reducing linear valve 28 so as not to open.

Since the second pilot pressure preparation control increases the supply current from the first set current I _SLA1 to the second set current I _SLA2 , as shown in FIG. 7, the target supply to the pressure-increasing linear valve 26 is performed. current I _SLA ^* the time until the current flowing through the actual pressure increasing linear valve 26 when it is changed to the second set current I _SLA2 reaches the second set current I _SLA2, target supply to the pressure-increasing linear valve 26 Compared with the case where the current I _SLA ^* is changed from 0 to the second set current I _SLA2 , it can be shortened. Further, the time from when the target supply current I _SLA ^* to the pressure increasing linear valve 26 is changed to the second set current I _SLA2 until the pressure increasing linear valve 26 is actually fully opened can be shortened. . That is, in the hydraulic brake system, the regulator 24 is in a state where pressure regulation according to the second pilot pressure P _PLT2 is actually performed from a state where pressure regulation according to the first pilot pressure P _PLT1 is performed. It is possible to shorten the time to become. Accordingly, the hydraulic brake system, a servo pressure P _SRV, while suppressing lowering of the servo pressure P _SRV during switching from the first state described above to the second state, to the target servo pressure P _SRV ^* It is possible to raise it early.

(E) Control program The control of the hydraulic brake system of this embodiment, specifically, the control of the servo pressure _PSRV , is performed by the ECU 30 executing a servo pressure control program whose flowchart is shown in FIG. This program is repeatedly executed at a short time pitch (for example, several μsec to several tens μsec). In this servo pressure control program, a switched flag FL, which is a flag indicating that the first state has been switched to the second state, is used. The switched flag FL has a flag value of 0 until it enters the second state, and when it is switched to the second state, the flag value is set to 1.

  In the servo pressure control program, first, in step 1 (hereinafter, “step” is abbreviated as “S”), it is determined whether or not a switching command for switching from the first state to the second state is issued, Until the switching command is issued, the state is in the first state, and the processing after S3 is skipped. In S2, the flag value of the switched flag FL is set to 0, and the elapsed time t described later is set to 0.

When the switching command is issued, first, in S3, the target servo pressure P _SRV ^* is determined based on the necessary hydraulic brake force described above, and in S4, the actual value is detected from the detected value of the servo pressure sensor 152. Servo pressure _PSRV is acquired. Next, in S5, it is determined whether or not the vehicle is in the second state based on whether or not the flag value of the switched flag FL is 1. In S6, whether or not the brake operation is performed is determined by whether the brake switch 162 is ON. It is determined by whether or not. When the flag value of the switched flag is 0 and the brake switch 162 is ON, the above-described second pilot pressure preparation control is being executed, and the processing from S7 is performed. When the flag value of the switched flag FL is 1, it is already in the second state, and the target supply current to the pressure increasing linear valve 26 and the pressure reducing linear valve 28 is determined by the normal feedback control in S13. Is done. Further, even if the flag value of the switched flag FL is 0, when the brake switch 162 is OFF, the second pilot pressure preparation control is not necessary, so that the second state is switched. That is, the flag value of the switched flag FL is set to 1 in S12, and the target supply current to the pressure increasing linear valve 26 and the pressure reducing linear valve 28 is determined by feedback control in S13.

S7 In the second pilot pressure preparation control in the following, first, in S7, whether the elapsed time t after the second pilot pressure preparation control is started the set time t ₀ or more is determined. If not passed a set time t ₀ or more is supplying the hydraulic fluid so as not to separate the spool 110 and the pilot piston 104 to the second pilot pressure chamber R10, at S8, the target of the pressure-increasing linear valve 26 The supply current I _SLA ^* is set to a relatively small first set current I _SLA1, and the target supply current I _SLR ^{* of the} pressure reducing linear valve 28 is set so as not to open even if the second pilot pressure increases. Current I _SLR0 .

Further, when the elapsed set time t _0, in S9, when the actual servo pressure P _SRV is determined whether reaches the target servo pressure P _SRV ^* has not reached yet the target servo pressure P _SRV ^* In S10, the target supply current I _SLA ^* of the pressure-increasing linear valve 26 is set to the second set current I _SLA2 that is the maximum current that maximizes the opening, and the target supply current of the pressure-reducing linear valve 28 is the same. I _SLR ^* is the current I _SLR0 set so that the valve does not open even when the second pilot pressure increases. When the target supply current of the pressure-increasing linear valve 26 and the pressure-decreasing linear valve 28 is determined in S8 or S10, the elapsed time t is added by one program execution interval Δt in S11.

On the other hand, when the actual servo pressure P _SRV reaches the target servo pressure P _SRV ^* in S9, the flag value of the switched flag FL is set to 1 in S12, and the pressure-increasing linear valve 26 is feedback-controlled in S13. And the target supply current to the pressure-reducing linear valve 28 is determined.

  Next, in S14, the pressure increasing linear valve 26 and the pressure reducing linear valve 28 are driven so that the supply current to the pressure increasing linear valve 26 and the pressure reducing linear valve 28 becomes the target supply current determined in S8, S10, and S13. A circuit control command is output. Thus, one execution of the servo pressure control program is completed.

10: Wheel 12: Brake device 14: Brake pedal [Brake operation member 16: Master cylinder 18: Anti-lock unit [ABS] 20: Reservoir [low pressure source] 22: High pressure source device [high pressure source] 24: Regulator 26: Pressure increase Linear valve [pressure increasing control valve] [SLA] 28: pressure reducing linear valve [SLR] 30: brake electronic control unit [control device] [ECU] 40: housing 42: first pressurizing piston 44: second pressurizing piston 46 ： Input piston 48 ： Stroke simulator 50 ： Division portion 56 ： ５８ 58 ： Main body portion 60 ： Projection portion 70 ： Communication passage 72 ： Communication switching valve 74 ： Low pressure passage 76 ： Low pressure source shutoff valve 86 ： Reaction force pressure sensor [P _RCT ] 96: high pressure source pressure sensor [P _ACC] 100: housing 102: a spool valve mechanism [the valve mechanism] 104: pilot pin Tong 110: Spool [valve] 112: spool holding cylinder 152: servo pressure sensor [P _SVR] 160: brake operation amount sensor [[delta] _PDL] 162: brake switch [SW _BR] 164: door switch [SW _DR] 166 : Ignition switch [SW _IG ] R1: first pressurizing chamber R2: second pressurizing chamber R3: inter-piston chamber R4: input chamber R5: counter chamber R6: reaction force chamber (inter-piston chamber & counter chamber) R7: buffer Chamber R8: First adjustment pressure chamber R9: First pilot pressure chamber R10: Second pilot pressure chamber R11: Second adjustment pressure chamber

Claims (7)

A brake operating member operated by a driver;
A brake device that is provided on the wheel and generates a braking force having a magnitude corresponding to the pressure of the hydraulic fluid supplied to the wheel;
(A-1) an input piston connected to the brake operation member and advanced by operation of the brake operation member; (A-2) a pressure piston disposed in front of the input piston; and (A- 3) an inter-piston chamber formed between the input piston and the pressurizing piston; (A-4) a pressurization chamber formed in front of the pressurizing piston; and (A-5) an inter-piston space. And an input chamber into which hydraulic fluid for applying a forward force to the pressurizing piston is introduced, and at least one of a hydraulic pressure in the inter-piston chamber and a hydraulic pressure in the input chamber A master cylinder for advancing the pressurizing piston and supplying hydraulic fluid in the pressurizing chamber pressurized by the advancement of the pressurizing piston to the brake device;
A high pressure source for supplying high pressure hydraulic fluid;
A regulator that regulates the high-pressure hydraulic fluid from the high-pressure source to a regulated pressure, and supplies the regulated hydraulic fluid to the input chamber of the master cylinder, and (B-1) regulates the regulated pressure to the regulated pressure (B-2) a valve body that is movable in the axial direction of the regulator and that receives the hydraulic pressure of the adjustment pressure chamber from one end side in its movable range. When the valve body is located on the other end side in the movable range, communication between the low pressure source and the adjustment pressure chamber is allowed, and communication between the high pressure source and the adjustment pressure chamber is blocked. A valve mechanism that blocks communication between the low pressure source and the adjustment pressure chamber by moving to one end side of the body, and permits communication between the high pressure source and the adjustment pressure chamber; and (B-3) the valve body (B-4) on the other end of the pilot piston A first pilot pressure chamber formed and introduced with hydraulic fluid pressurized from the pressurization chamber of the master cylinder; and (B-5) a second formed between the pilot piston and the valve body. A pilot pressure chamber; and (I) the pilot piston is brought into contact with the valve body and moved together with the valve body by a first pilot pressure which is a hydraulic pressure of the first pilot pressure chamber, so that the adjustment pressure is The valve body is moved by a first state that is regulated to a magnitude corresponding to the first pilot pressure, and (II) a second pilot pressure that is a hydraulic pressure of the second pilot pressure chamber, thereby the adjustment A regulator that selectively realizes a second state in which the pressure is regulated to a magnitude corresponding to the second pilot pressure;
A second pilot pressure chamber hydraulic fluid supply device for supplying hydraulic fluid to the second pilot pressure chamber of the regulator and generating hydraulic pressure in the second pilot pressure chamber;
A hydraulic brake system including a control device that controls the second pilot pressure by controlling the second pilot pressure chamber hydraulic fluid supply device to control the adjusted pressure,
The control device is
In the second state, the second pilot pressure is set to a deviation between an actual hydraulic pressure in the adjustment pressure chamber and a target hydraulic pressure in the adjustment pressure chamber determined in accordance with an operation performed on the brake operation member. Based on feedback control,
In the case of switching from the first state to the second state after the operation of the brake operation member is started, the second body is in contact with the valve body and the pilot piston before the feedback control is started. The hydraulic fluid is once supplied to the pilot pressure chamber, and then the valve body and the pilot piston are brought into contact with each other until the valve body and the pilot piston are separated and the adjustment pressure reaches the target hydraulic pressure. A hydraulic brake system characterized by executing second pilot pressure preparation control for supplying hydraulic fluid to the second pilot pressure chamber at a flow rate larger than a flow rate when supplying hydraulic fluid in a state. The second pilot pressure preparation control is
The hydraulic fluid is supplied to the second pilot pressure chamber until a hydraulic fluid having a set fluid amount set so as not to separate the valve body and the pilot piston is introduced. Thereafter, the hydraulic fluid having the set fluid amount is supplied. 2. The hydraulic brake system according to claim 1, wherein hydraulic fluid is supplied to the second pilot pressure chamber at a flow rate larger than a flow rate when supplying the second pilot chamber to the second pilot chamber. The second pilot pressure control device comprises:
A pressure-increasing control valve provided between the high-pressure source and the second pilot pressure chamber and allowing a flow of hydraulic fluid at a larger flow rate than when the supplied current is small,
The second pilot pressure preparation control is
When hydraulic fluid is once supplied to the second pilot pressure chamber in a state where the valve body and the pilot piston are in contact with each other, a first set current is supplied to the pressure increase control valve, and then the adjustment pressure The hydraulic brake according to claim 1 or 2, wherein a second set current that is larger than the first set current is supplied to the pressure increase control valve until the target hydraulic pressure is reached. system.   4. The hydraulic brake system according to claim 3, wherein the second set current is a current that allows the hydraulic pressure control valve to allow a flow of hydraulic fluid having a maximum flow rate. 5. The second pilot pressure preparation control is
For the set time, the first pressure increase control valve is configured so that a set amount of hydraulic fluid set so as not to separate the valve body and the pilot piston is introduced into the second pilot chamber. The hydraulic brake system according to claim 3 or 4, wherein one set current is supplied, and then a current supplied to the pressure increase control valve is changed to the second set current. The regulator is
6. The pressure receiving area for receiving the second pilot pressure on the other end side of the valve body is smaller than the pressure receiving area for receiving the second pilot pressure on one end side of the pilot piston. The hydraulic brake system according to any one of the above. The master cylinder is
It has a partition portion in which the interior is partitioned into two liquid chambers and an opening is formed, and includes a housing that houses the pressure piston on the front side of the partition portion and the input piston on the rear side,
The pressure piston is
It has a main body part with a ridge formed at the rear end, and a protruding part that extends rearward from the main body part and protrudes rearward from the opening of the partition part,
The input chamber of the master cylinder is
A partition is formed between the rear surface of the flange and the front surface of the partition portion on the outer periphery of the protruding portion of the pressure piston,
The master cylinder is
A pressure chamber is provided in front of the flange on the outer periphery of the main body of the pressure piston, and is provided with a counter chamber facing the input chamber with the flange interposed therebetween, and the pressure of the hydraulic fluid in the inter-piston chamber of the pressure piston is reduced. The pressure receiving area to be received is equal to the pressure receiving area to receive the pressure of the hydraulic fluid in the facing chamber in the pressurizing piston,
The hydraulic brake system
In the first state, the chamber between the pistons is shut off from the opposing chamber, and the opposing chamber is communicated with a low pressure source to depend on both the hydraulic pressure in the inter-piston chamber and the hydraulic pressure in the input chamber. To advance the pressure piston,
In the second state, the pressure piston is moved forward by relying only on the hydraulic pressure of the input chamber by communicating the inter-piston chamber with the counter chamber. The hydraulic brake system according to any one of the above.

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