JP2001047994A - Brake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a flow rate of a hydraulic fluid flowing into a master cylinder, in the case of controlling a brake cylinder fluid pressure in a range where the brake cylinder fluid pressure is higher than a master cylinder fluid pressure. SOLUTION: Auxiliary energizing pressure is increased with an ordinary gradient when a master cylinder fluid pressure comes to a start pressure PM0 or more (at the time of initial pressure increase (2)). The auxiliary energizing pressure is held in the case of a set pressure P1 or more of master cylinder fluid pressure ((3), (4)). The auxiliary energizing pressure is not changed even when the master cylinder fluid pressure is changed in a condition of the set pressure P1 or more. The auxiliary energizing pressure is thereafter suppressed in its decreasing gradient when the master cylinder fluid pressure is decreased. A flow rate flowing into a master cylinder is suppressed, an increasing gradient of brake-operation force is suppressed in its increasing gradient, and control hunting is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device, and more particularly, to a brake device capable of setting a brake cylinder pressure higher than a master cylinder pressure.

[0002]

2. Description of the Related Art An example of a brake device of this kind is disclosed in Japanese Patent Application No. 10-8, filed by the applicant of the present invention and has not been disclosed.
383. The brake device described in this specification includes (1) a brake cylinder that operates a brake by hydraulic pressure, (2) a master cylinder that generates hydraulic pressure according to the operating force of a brake operating member, and (3) a brake cylinder that A control valve device that is provided in the middle of the main fluid passage connecting the cylinder and the master cylinder, and that controls a communication state between the brake cylinder and the master cylinder; and (4) controls the control valve device based on a brake operating force. A control valve device control device, and (5) a pressurizing device that pressurizes the hydraulic fluid supplied from the hydraulic fluid supply device and supplies the main fluid passage from the control valve device to the brake cylinder side. Including. In this brake device, if the hydraulic fluid is supplied from the pressurizing device in a state where the brake cylinder is disconnected from the master cylinder by the control valve device, the brake cylinder hydraulic pressure is higher than the master cylinder hydraulic pressure. Further, if the brake cylinder is communicated with the master cylinder, the flow of the hydraulic fluid from the brake cylinder to the master cylinder is allowed, and the brake cylinder fluid pressure is reduced.

[0003]

SUMMARY OF THE INVENTION Such a control of the brake cylinder pressure is performed when the brake operating member is moved in a direction to increase the master cylinder pressure. In this case, even if the control valve device is almost kept in the shut-off state, and is rarely brought into the communication state, the driver hardly feels the influence because the brake operating member is moving. Further, in a state where the brake operating member is moved in a direction to decrease the master cylinder hydraulic pressure, even if the control valve device is almost kept in the communicating state and is rarely shut off, the influence is not affected. After all, it is hardly felt by the driver.

[0004] However, if the control of the brake cylinder fluid pressure is performed at a time when the operation force of the brake operation member should be kept constant, the brake operation member is affected. When the hydraulic fluid is caused to flow into the master cylinder to reduce the brake cylinder hydraulic pressure, the brake operating member is likely to be pushed back by this flow. At this time, most drivers cannot retreat the brake operating member by an amount corresponding to the inflow amount of the hydraulic fluid. Therefore, the brake operation force increases, and control is performed to increase the brake cylinder hydraulic pressure accordingly. Conversely, when hydraulic fluid is supplied from the master cylinder to the pressurizing device to increase the hydraulic pressure of the brake cylinder, the brake operating force must be increased unless the brake operating member is moved forward with the outflow of hydraulic fluid. Although not constant, most drivers cannot perform this forward maneuver completely. Generally, the brake operation force is reduced, and therefore, control for reducing the brake cylinder hydraulic pressure is performed.

[0005] A case where the increase or decrease of the brake operation force contrary to the driver's intention affects the control of the control valve device based on the brake operation force, and the control of the brake cylinder fluid pressure is not performed well. There is. A specific example will be described with reference to FIG. Here, the brake operation is performed so that the hydraulic pressure of the brake cylinder becomes the same as after the booster has been boosted, at the same level as when the brake operation force was boosted at the same boosting factor as before the boost limit. It is assumed that the control valve device is controlled based on the master cylinder hydraulic pressure corresponding to the force. Further, the master cylinder is a hydraulic fluid supply device, the hydraulic fluid supplied from the master cylinder is increased in pressure by the pressurizing device and supplied to the brake cylinder,
It is assumed that the brake cylinder fluid pressure is increased. The pressurizing device performs pseudo assisting. The increase in the brake cylinder hydraulic pressure at this time is referred to as assisting by the pressurizing device, and the hydraulic pressure generated by the assisting is referred to as assisting pressure.

If the driver tries to keep the brake operating force that has been increased up to a certain level in a state in which assistance is provided by the pressurizing device, the brake cylinder hydraulic pressure that has been excessively increased is reduced. It is assumed that the control valve device is brought into the communication state. When the control valve device is brought into the communicating state, the hydraulic fluid flows into the master cylinder from the brake cylinder side and pushes back the brake operating member. As described above, since the driver cannot sufficiently follow the backward movement of the brake operating member, the brake operating force increases, the master cylinder hydraulic pressure increases, and control for increasing the brake cylinder hydraulic pressure is performed. Since the increase in the brake cylinder pressure is not intended by the driver, the driver decreases the brake operation force. Therefore, as shown in FIG. 11A, the master cylinder hydraulic pressure is reduced, and the assist by the pressurizing device is also reduced as shown in FIG. Alternatively, the driver relaxes the brake operating force in an attempt to allow the brake operating member to retreat, but this loosening operation is delayed. Therefore, after the master cylinder hydraulic pressure once increases, it decreases as shown in (A), and accordingly, the assistance by the pressurizing device is also reduced as shown in (B). As a result, the brake cylinder hydraulic pressure is also reduced, but since this reduction is greater than the driver's intention, the driver increases the brake operating force. Alternatively, the brake operation force is increased in order to cancel the delay in the loosening operation of the brake operation member. With the increase in the operating force, the master cylinder hydraulic pressure increases as shown in (C), and the assist by the pressurizing device is also increased as shown in (D). Thereafter, as shown in (E), the same phenomenon as described with respect to the portion shown in (A) occurs, and thereafter, the brake operating force, the master cylinder hydraulic pressure, and the reduction in assisting by the pressurizing device are reduced. , Hunting occurs in which the control of the brake cylinder hydraulic pressure becomes a vibration state. This problem,
This is not limited to the case where the control valve device is controlled based on the master cylinder hydraulic pressure, and generally occurs when the control valve device is controlled based on a predetermined rule.

In the case where both the above-described main liquid passage and the hydraulic fluid supply passage connected to the pressurizing device are connected to the pressurizing chamber of the master cylinder, the control device controls the pressurizing device during control. Is constantly operated, the hydraulic fluid is caused to flow into the master cylinder via the main fluid passage (control valve device), while the hydraulic fluid is supplied to the pressurizing device via the hydraulic fluid supply passage. This causes the hydraulic fluid to flow out of the master cylinder. In this case, whether the hydraulic fluid flows out or inflows from the master cylinder is determined by the difference between the outflow flow rate and the inflow flow rate. In the case where the brake circuit includes a circulation circuit including a control valve device, a pressurizing device, and a brake cylinder, if the hydraulic fluid runs short in the circulation circuit, the hydraulic fluid flows out of the master cylinder, and the hydraulic fluid is discharged. If it is left, it will be allowed to flow. In these cases as well, the above-described effects appear on the brake operating member,
Similar hunting occurs.

The present invention has been made in view of the above circumstances as an object to avoid occurrence of hunting and to enable good control of brake cylinder hydraulic pressure. This problem is solved by using the following aspects of the brake device. Each mode is described in the same manner as in the claims, divided into sections, each section is numbered, and described in the form of citing the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the present invention, and the technical features described in this specification and their combinations should not be construed as being limited to the following sections. Also, 1
If more than one item is listed in a section, it is not always necessary to adopt all items together, but it is also possible to extract and adopt only some items. (1) A brake cylinder that operates a brake by hydraulic pressure, a master cylinder that generates hydraulic pressure in accordance with the operating force of a brake operating member, and is provided in the middle of a main liquid passage that connects the brake cylinder and the master cylinder. A control valve device for controlling the communication between the brake cylinder and the master cylinder, a control valve device control device for controlling the control valve device in accordance with a predetermined rule, and a hydraulic fluid supplied from a hydraulic fluid supply device. Pressurizes the main liquid passage,
The control valve device controls at least one of the outflow flow rate and the inflow flow rate of the hydraulic fluid in the master cylinder by the control valve device by the control valve device control device. A brake device (Claim 1) characterized in that it includes a flow rate reduction device that reduces the flow rate of at least one of the outflow flow rate and the inflow flow rate when the flow rate is controlled according to the following. If at least one of the inflow flow rate and the outflow flow rate of the hydraulic fluid in the master cylinder is reduced, at least one of the increasing gradient and the decreasing gradient of the brake operating force is reduced, so that the driver can easily control the brake operating force. That is, hunting can be prevented or reduced. It is particularly effective to reduce both the inflow flow rate and the outflow flow rate, but it is not essential. If either the inflow flow rate or the outflow flow rate is reduced, the control of the brake operating force becomes easier. And hunting can be avoided. In addition,
The control valve device may be controlled electrically or by another means. For example, it is also possible to employ a pilot control valve that controls the master cylinder hydraulic pressure and the brake cylinder hydraulic pressure as pilot pressures. Further, even if it is a simple on-off valve, a hydraulic pressure control valve or a flow control valve in which the differential pressure across the control valve itself or the flow rate of the hydraulic fluid flowing through the control valve is electrically or non-electrically controlled. You may. The hydraulic fluid supply device may be a master cylinder or the like having a function of pressurizing the hydraulic fluid, or may simply be a reservoir or the like that stores the hydraulic fluid. (2) a brake cylinder that operates a brake by hydraulic pressure, a master cylinder that generates hydraulic pressure according to the operating force of a brake operating member, and a brake cylinder that pressurizes hydraulic fluid supplied from a hydraulic fluid supply device. A pressurizing device for supplying a main fluid passage connecting to the master cylinder; and a master fluid passage provided on the master cylinder side from a portion of the main fluid passage to which the hydraulic fluid is supplied by the pressurizing device. A control valve device that allows the flow of hydraulic fluid toward the cylinder side at a flow rate corresponding to the supplied electric energy, and a control valve that controls the supplied electric energy to the control valve device based at least on the operating force of the brake operation member The control valve device controls the flow rate of the hydraulic fluid flowing into the master cylinder via the control valve device. Brake system which comprises a flow reducing device for reducing than the inflow rate when controlled by apparatus (claim 2). In the brake device according to the present mode, the flow rate of inflow into the master cylinder is reduced, so that the increasing gradient of the brake operation force is suppressed. As a result, the increase gradient of the master cylinder hydraulic pressure is suppressed, and the occurrence of hunting is thereby suppressed. Also, if the increasing gradient of the braking force is suppressed,
It becomes easy for the driver to keep the brake operation force substantially constant, thereby also suppressing the occurrence of hunting.
When the control valve device is controlled based on the brake operation force, if the brake operation force is kept substantially constant, the control of the control valve device is stabilized, and the control of the brake cylinder fluid pressure is favorably converged. . The brake operation force can be detected not only by detecting the force applied to the brake operation member itself but also by detecting the amount corresponding to the brake operation force such as the master cylinder hydraulic pressure on a one-to-one basis. The control valve device allows the flow of the hydraulic fluid at a flow rate corresponding to the supplied electric energy. For example, an electromagnetic flow control valve corresponds to the control valve device. It can also be. For example, if the on-off valve is alternately switched between the open state and the closed state and the time ratio between the open state and the closed state is changed, the flow rate of the hydraulic fluid flowing to the master cylinder side can be controlled. If a throttle is provided in parallel with the on-off valve, and the operating fluid flows into the master cylinder via the throttle in the closed state of the on-off valve, the inflow flow rate can be controlled in two stages, large and small. (3) The flow reduction device reduces the inflow flow rate when a predetermined condition is satisfied, than a flow rate when a control valve device is controlled by the control valve device control device. Brake device according to paragraph (1) or (2). If the flow rate into the master cylinder is reduced, the control of the brake cylinder fluid pressure becomes easier, but at the same time,
When it is necessary to rapidly increase and decrease the brake cylinder fluid pressure, a delay in control cannot be avoided. Therefore, it is desirable that reduction of the flow rate by the flow rate reduction device is limited to a case where it is truly necessary or a case where the control is not adversely affected. Therefore, in the embodiment of this section, the power consumption is reduced when a predetermined condition is satisfied. For example, when it is estimated that the actual change speed of the braking force may be lower than the change speed requested by the driver, the flow rate is reduced assuming that a predetermined condition is satisfied. is there. This corresponds to a case where the driver's brake operation force is equal to or higher than a predetermined set operation force, or a case where the brake operation speed is within a predetermined set speed. Further, a condition that the pressure reduction control time is within a predetermined set time may be added. These conditions will be described in more detail in section (4) (next section), (11) and (12). (4) The flow rate reduction device includes an inflow flow rate suppression unit that controls the control valve device to suppress the inflow flow rate of the hydraulic fluid flowing into the master cylinder.
The brake device according to any one of the above aspects (3) (Claim 3). By controlling the control valve device, the communication state between the brake cylinder and the master cylinder can be controlled, and the flow rate of flow into the master cylinder can be controlled. For example, the flow rate of the hydraulic fluid flowing to the master cylinder via the control valve device is controlled so as to be smaller than when the flow rate is controlled according to a predetermined rule.
When the control of the communication state in the control valve device is performed by controlling the supply electric energy determined according to the brake operation force, the change amount of the supply electric energy is made smaller than the amount corresponding to the change amount of the brake operation force. I do. In addition, even if an upper limit is provided for the amount of change in the supplied electric energy, the inflow flow rate can be suppressed. Further, even if a dead zone is provided in the control, the inflow flow rate can be suppressed. For example, in the case where the control valve device is controlled based on the brake operation force, if the brake operation force is equal to or more than a predetermined set operation force, the communication state (the degree of communication) is kept constant. It is. In a state where the brake operation force is equal to or greater than the set operation force, even if the brake operation force is reduced, the opening area of the control valve device is not increased accordingly, so that the inflow flow rate can be suppressed. If the control valve device is operated with the master cylinder hydraulic pressure as the pilot pressure, a hydraulic pressure equal to the set hydraulic pressure is transmitted as the pilot pressure even if the master cylinder hydraulic pressure is equal to or higher than the set hydraulic pressure. So that That is, when the pressure is equal to or higher than the set hydraulic pressure, the pressure is reduced to the set hydraulic pressure and transmitted. When the control valve device is controlled by controlling the supplied electric energy,
An upper limit for the supplied electric energy is set. For example, when any one of the following conditions is satisfied, the inflow flow rate can be suppressed. When the brake operation force is equal to or higher than a predetermined set operation force, when the brake operation force is equal to or lower than the set operation force, and when the brake operation speed (operating force reduction speed) is within a predetermined set speed, This is a case where the brake operation force is equal to or less than the set operation force and the decompression continuation time is within a predetermined inflow flow rate suppression allowable time. In the region where the brake operating force is equal to or higher than the set operating force and the braking force is equal to or higher than the set braking force, it is not necessary to control the braking force. It is not necessary to control according to the rate of decrease of the operating force), and the inflow flow rate is suppressed. Regarding the above, when the operation speed is within the set speed, the necessity of controlling (in this case, decreasing) the braking force in accordance with the operation speed is low, so that the inflow flow rate is suppressed. When the operation speed is within the set speed, the braking force may be maintained. Will be described. The time elapsed from the start of depressurization exceeds the allowable flow rate of the inflow flow rate when the driver thinks that the braking force has not decreased to the braking force requested by the driver, and the required braking force is promptly reduced. It is desirable to reduce the braking force at a normal speed so as to reduce the braking force. When the decompression gradient is suppressed, the rate of decrease of the braking force is reduced, so that a difference occurs between the actual braking force and the braking force requested by the driver. The longer the pressure reduction control time, the larger the value. Therefore, it is desirable that the pressure reduction gradient is suppressed only within the above-mentioned inflow flow rate suppression allowable time. If it is estimated that the difference between the actual braking force and the braking force required by the driver is equal to or greater than the set braking force, it is not desirable to suppress the pressure reduction gradient. Therefore, the inflow flow rate is suppressed while the decompression continuation time is within the predetermined inflow flow rate suppression allowable time, and the suppression of the inflow flow rate is released when the inflow flow rate suppression allowable time is exceeded. (5) The control valve device includes an electromagnetic flow control valve that allows a flow of the hydraulic fluid from the brake cylinder side to the master cylinder side at an opening degree according to the supplied electric energy, and the inflow flow rate control unit includes: The brake device according to the above mode (4), further comprising an opening suppression unit that suppresses the opening of the electromagnetic flow control valve (Claim 4). If the amount of hydraulic fluid supplied from the pressurizing device is constant and the opening of the electromagnetic flow control valve is reduced,
The flow rate of the working fluid flowing through the electromagnetic flow control valve toward the master cylinder can be suppressed, and the flow rate of the working fluid flowing into the master cylinder can be suppressed. (6) The control valve device is arranged such that the valve seat approaches the valve seat.
A valve element provided detachably, an urging member for urging the valve element in a direction to separate the valve element from the valve seat, and a magnetic force corresponding to the supplied electric energy in a direction to bring the valve element close to the valve seat. An electromagnetic control device including an electromagnetic drive device, wherein the inflow rate suppressing unit includes an opening area control unit that controls an opening area between the valve element and the valve seat by controlling the supplied electric energy. The brake device according to the above mode (4) or (5). In the electromagnetic control valve according to this aspect, a differential pressure acting force Fp corresponding to a differential pressure between before and after, in a direction for separating the valve element from the valve seat,
The urging force Fs by the urging member is applied, and the magnetic force Fe acts in the opposite direction. That is, a state where the sum of the differential pressure acting force Fp and the urging force Fs becomes equal to the magnetic force Fe (Fp + Fs).
= Fe) determines the relative position of the valve element to the valve seat. Therefore, if the magnetic force Fe is controlled, the opening area between the valve element and the valve seat (the opening area of the electromagnetic control valve) can be controlled, and the flow rate of the hydraulic fluid flowing through the electromagnetic control valve can be controlled. Can be. In the electromagnetic control valve, the urging member is urged in a direction to bring the valve element closer to the valve seat, and the electromagnetic driving device is moved in a direction to move the valve element away from the valve seat in a magnetic field corresponding to the supplied electric energy. It can also be a device for generating a force. In this case, a state in which the sum of the differential pressure acting force Fp and the magnetic force Fe becomes equal to the urging force Fs (Fp + Fe = Fs).
Determines the relative position of the valve element to the valve seat, and determines the opening area. As in the case described above, the opening area can be controlled by controlling the supplied electric energy. (7) When the control valve device control device controls the control valve device based on the master cylinder hydraulic pressure to increase the brake cylinder hydraulic pressure at a constant boost factor. The brake device according to any one of the above modes (1) to (6), including a boost controller that controls the hydraulic pressure so as to be equal to the hydraulic pressure. In the electromagnetic hydraulic pressure control valve described in the item (6), the relative position between the valve element and the valve seat is determined so that the differential pressure acting force Fp, the magnetic force Fe, and the urging force Fs satisfy the above-described relationship. If the magnetic force Fe is controlled so that a desired differential pressure is obtained with the valve seated on the valve seat, the brake cylinder hydraulic pressure can be controlled. (8) The brake device according to any one of (1) to (7), wherein the flow rate reducing device includes a discharge amount suppressing unit that suppresses a discharge amount of the working fluid of the pressurizing device. 5). When the communication state of the control valve device is constant,
If the discharge amount of the working fluid of the pressurizing device is suppressed, the flow rate of the working fluid flowing into the master cylinder is correspondingly suppressed. The pressurizing device can be a pump device that includes a pump and a pump motor that drives the pump. (9) The flow rate reduction device includes a supply amount suppression device that suppresses a supply amount of the working fluid supplied from the working fluid supply device to the pressurizing device. The brake device according to claim 7 (claim 7). If the supply amount of the working fluid supplied to the pressurizing device is suppressed, the amount of the working fluid discharged from the pressurizing device can be suppressed, and the flow rate flowing into the master cylinder can be suppressed. The supply control device is
Opening / closing that can be switched between an open state and a closed state even if it includes a flow control valve that is provided between the hydraulic fluid supply device and the pressurizing device and that can control the flow rate of the hydraulic fluid flowing between them It may include a valve. The hydraulic fluid supply device may be a master cylinder or a reservoir such as a master reservoir that stores the hydraulic fluid at atmospheric pressure and replenishes the hydraulic fluid to the master cylinder. In the case where the control is performed in a region higher than the pressure, when the hydraulic fluid of the master cylinder is pressurized, the energy consumption of the pressurizing device can be reduced. (10) When the degree of the driver's request for increasing the brake cylinder hydraulic pressure is lower than a predetermined request degree, the supply amount restricting device suppresses the supply amount of the hydraulic fluid. The brake device according to the mode (8) or (9), which is a device (claim 7). When the brake cylinder pressure is controlled in a region higher than the master cylinder pressure, the brake cylinder pressure is increased by the hydraulic fluid supplied from the pressurizing device. Therefore, it is desirable to suppress the discharge amount when the degree of pressure increase request by the driver is low. The pressure increase request can be acquired, for example, based on the amount of change in the brake operation force. The setting request degree may be a constant value or a variable value as described in the following section. (11) The conditional supply amount suppressing device includes a setting request degree determining unit that determines the setting request degree based on a past control state of the conditional supply amount suppressing device. The brake device according to claim 10, wherein the supply amount is suppressed when the degree of the pressure increase request is smaller than the determined set request degree. A threshold value for determining whether the driver's braking increase request is large,
That is, the setting request degree can be determined based on the past control state. For example, as described in [Embodiment of the invention], when in the suppression state, the suppression continuation threshold value that determines whether to continue the suppression state, and when not in the suppression state, the suppression state And a suppression switching threshold value that determines whether or not to switch to the setting request degree. When the suppression state is in the suppression state, the suppression control is performed while the braking request is smaller than the suppression continuation threshold value. If the control state is not the suppression state and the value becomes smaller than the suppression switching threshold value, the control can be switched to the suppression control. The larger the suppression continuation threshold is, the easier the suppression control is to be continued, and the larger the suppression switching threshold is, the easier it is to switch to the suppression control. Therefore,
If these thresholds are increased when the past suppression control time is short, the time in the suppression state can be lengthened, or the state can be easily switched to the suppression state. If the elapsed time after the switching between the suppression state and the non-suppression state is within the set time, the suppression continuation threshold value is increased, and the suppression switching threshold value is decreased. In addition, it is difficult to switch from the suppression control to the non-suppression control and to switch from the non-suppression control to the suppression control. (12) The pressurizing device is a pump device including a pump for pressurizing the working fluid supplied from the working fluid supply device, and an electric motor for driving the pump, and the flow rate reducing device includes a pump for the electric motor. Including a motor control unit that suppresses the discharge amount of the pump by controlling the operation state (1)
The brake device according to any one of paragraphs (11) to (11).
If the supply current to the electric motor is reduced when the discharge pressure of the pump is the same, the rotation speeds of the electric motor and the pump are reduced, and the discharge amount of the pump is reduced. (13) a pressure reducing reservoir provided between the pressure reducing reservoir, the pressure reducing reservoir and the brake cylinder, the pressure reducing valve being switchable between a communication state for communicating these and a shutoff state for breaking off the brake device, and a brake cylinder And a pressurizing device, and a holding valve that can be switched between a communicating state in which they are communicated and a shutoff state in which they are shut off, and a hydraulic pressure of the brake cylinder by controlling the pressure reducing valve and the holding valve. (1) The brake device according to any one of (1) to (12), including a brake fluid pressure control device for controlling pressure reduction, and wherein the flow rate reduction device includes a pressure reduction control unit that switches the pressure reduction valve to a communication state. If the pressure reducing valve is switched to the communicating state, the hydraulic fluid of the brake cylinder can flow out to the pressure reducing reservoir. The hydraulic fluid is caused to flow not into the master cylinder but into the pressure reducing reservoir. (14) The hydraulic fluid supply device is the master cylinder, the pressurizing device is a pump device that pressurizes hydraulic fluid supplied from the master cylinder, and the flow rate reducing device is a pump device that supplies a hydraulic fluid to the pump device. The brake device according to any one of (1) to (13), further including an outflow flow rate reducing device configured to reduce an outflow flow rate of the hydraulic fluid discharged from the master cylinder for supplying the hydraulic fluid. ). According to the brake device described in this section, the outflow flow rate from the master cylinder is reduced. In the case where the hydraulic fluid supply device is a master cylinder, the discharge amount suppression unit according to item (8), the supply amount suppression device according to any one of items (9) to (11),
The flow rate reduction device including the motor control unit described in the item 2) is an aspect of the outflow flow rate reduction device described in the item 2. Further, when the operating speed of the pump device is constant, the outflow from the master cylinder can be reduced by controlling the control valve device. For example, when it is necessary to increase the brake cylinder fluid pressure, the communication state of the control valve device is controlled so as to allow a larger flow rate of the hydraulic fluid than the communication state corresponding to the brake operating force. For example, since the amount of hydraulic fluid returned to the master cylinder increases, the amount of hydraulic fluid flowing out of the master cylinder can be reduced as a result. In this case, the increasing gradient of the brake cylinder hydraulic pressure is smaller than when the communication state corresponding to the brake operation force is set. As described in the item (4), for example, when the brake operation force is equal to or more than a predetermined set operation force, the outflow flow rate is reduced when the brake operation force is equal to or less than the set operation force and the brake operation speed is reduced. When the (operating force increasing speed) is within a predetermined set speed, when the brake operating force is equal to or less than the set operating force, and when the pressure increasing duration is within a predetermined outflow flow rate allowable time. Can be done. (15) By supplying the hydraulic fluid output from the pressurizing device to the brake cylinder in a state where the brake cylinder is disconnected from the master cylinder by the control valve device, the hydraulic pressure of the brake cylinder is higher than the hydraulic pressure of the master cylinder. The brake fluid pressure control device, which controls the fluid pressure, controls the brake cylinder to communicate with the master cylinder by a control valve device, and allows the hydraulic fluid to flow out to the master cylinder, thereby reducing the brake cylinder fluid pressure. A brake fluid pressure control device provided with a flow reduction device for reducing the inflow flow rate of the hydraulic fluid in the master cylinder from an inflow flow rate corresponding to a case where the control valve device is controlled according to a predetermined rule. . The flow rate reduction device may have the features described in any one of the items (2) to (14).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some specific embodiments of the present invention will be described below in detail with reference to the drawings.
In FIG. 1, reference numeral 10 denotes a brake pedal as a brake operating member, and the brake pedal 10 is connected to a master cylinder 14 via a vacuum booster 12. The master cylinder 14 is of a tandem type, in which two pressurizing pistons are slidably fitted in series and each other in a housing, so that two pressurizing chambers are arranged in front of each pressurizing piston in the housing. It is formed independently. The master cylinder 14 mechanically generates a hydraulic pressure having the same height in each of the pressurizing chambers in accordance with a brake operation force which is a depression force of the brake pedal 10.

Since the vacuum booster 12 is a well-known type, its detailed description is omitted. However, the vacuum booster 12 has a variable pressure chamber and a negative pressure chamber. 14 is output. After the pressure in the transformer chamber increases to atmospheric pressure,
It does not increase even if the brake pedal 10 is depressed further deeply. The state in which the pressure in the variable pressure chamber has reached the atmospheric pressure is the limit at which the booster can assist the brake operation force. When the booster reaches the assisting limit, the master cylinder 12
The hydraulic pressure at is the assisting limit pressure. In the present embodiment, as will be described later, effectiveness characteristic control for assisting the braking force is performed from the time when the vacuum booster 12 reaches the assisting limit.

[0011] This brake device is of two systems of front and rear,
In one pressurizing chamber of the master cylinder 14, a brake cylinder 5 for operating the respective brakes 54 of the left and right front wheels is provided.
6 are connected. A brake cylinder 60 for operating the respective brakes 58 of the left and right rear wheels is connected to the other pressurizing chamber.

In the hydraulic system on the front wheel side, the master cylinder 14 and the brake cylinders 56 of the left and right front wheels FL, FR are connected by a main fluid passage 64. The main liquid passage 64 is branched in a bifurcated manner after extending from the master cylinder 14, and one main passage 66 and two branch passages 68 are connected to each other. A pressure control valve 70 is provided in the middle of the main passage 66. The above-described brake cylinder 5 is provided at the end of each branch passage 68.
6 are connected to each other. A pump passage 72 is connected to a portion of the main liquid passage 64 between the pressure control valve 70 and the brake cylinder 56, and a pump 7
4 are provided. The pump 74 includes a pump motor 76
Driven by Pump 74 and pump motor 7
A pressurizing device 78 as a pressurizing device is configured by 6 and the like.

In FIG. 2, a pressure control valve 70 controls the communication between the master cylinder 14 and the brake cylinder 56 and electromagnetically controls the pressure difference between them. . The pressure control valve 70 includes a housing (not shown), a valve 80 for controlling the flow state of the hydraulic fluid between the master cylinder side and the brake cylinder side in the main fluid passage 64, and a valve seat 82 on which it is seated. And a solenoid 84 for generating a magnetic force for controlling the relative movement of the valve element 80 and the valve seat 82. In the present embodiment, a control valve device is configured by the pressure control valve 70 and the like.

In the pressure control valve 70, in a non-operating state (OFF state) where the solenoid 84 is not excited,
The valve element 80 is separated from the valve seat 82 by the elastic force of the spring 86. This allows a bidirectional flow of the hydraulic fluid between the master cylinder side and the brake cylinder side in the main fluid passage 64, and as a result, if a brake operation is performed, the brake cylinder 56 becomes the same as the master cylinder 14 and the like. It can be changed by pressure. During this braking operation, a force acts on the valve element 80 in a direction away from the valve seat 82. Therefore, as long as the solenoid 84 is not excited, even if the master cylinder hydraulic pressure, that is, the brake cylinder hydraulic pressure becomes high, the valve element 80 Does not sit on the valve seat 82. That is, the pressure control valve 70 is a normally open valve.

On the other hand, in the operation state (ON state) in which the solenoid 84 is excited, the armature 88 is attracted by the magnetic force of the solenoid 84 and the armature 8
A valve 80 that moves integrally with the valve seat 8 is seated on a valve seat 82. At this time, the valve 80 has an attractive force F ₁ based on the magnetic force of the solenoid 84, a differential pressure acting force F ₂ based on a difference between the brake cylinder hydraulic pressure and the master cylinder hydraulic pressure, and an elastic force F _{3 of the} spring 86. And the sums act in opposite directions. Large attraction force F ₁ against the pressure differential force F ₂ based on the difference between the brake cylinder pressure and the master cylinder pressure,
In the region where the formula F ₂ ≦ F ₁ -F ₃ is satisfied, seated valve member 80 is in the valve seat 82, the outflow of the working fluid is prevented from the brake cylinder 56. When the high-pressure hydraulic fluid is supplied from the pump 74, the hydraulic pressure of the brake cylinder 56 is increased and becomes higher than that of the master cylinder 14.

When the differential pressure acting force F ₂ increases with an increase in the brake cylinder hydraulic pressure, and the formula F ₂ > F ₁ −F ₃ is satisfied, the valve element 80 separates from the valve seat 82 and the brake cylinder 56 The hydraulic fluid is returned to the master cylinder 12 and decompressed. In this equation, ignoring the elastic force F _3, the brake cylinder pressure will be controlled to the difference pressure higher hydraulic pressure based on the solenoid attractive force F ₁ to the master cylinder pressure. The valve seat 82 of the valve 80
Is also determined by the differential pressure acting force, the suction force, and the elastic force described above, so that the distance between them, that is, the opening can be controlled by controlling the suction force. The magnitude of the suction force F ₁ is the magnetic force of the solenoid 84, as represented graphically in Figure 3, is designed to vary linearly in accordance with the magnitude of the excitation current I of the solenoid 84 .

As shown in FIG. 1, the pressure control valve 70 is provided with a bypass passage 92, and a bypass valve 94 is provided in the middle of the bypass passage 92 as a check valve. In the unlikely event that the brake pedal 10 is depressed, the pressure control valve 70 is closed due to the fluid force generated in the movable member in the pressure control valve 70, or the pressure control valve 70 is mechanically locked and remains closed. Even if
This is to ensure the flow of the hydraulic fluid from the master cylinder 14 to the brake cylinder 56.

In the middle of each branch passage 68, a pump passage 7
On the side of the brake cylinder 56 from the point of connection with
A holding valve 100 which is a normally-open electromagnetic on-off valve is provided. The holding valve 100 is excited to be in the closed state, and in this state, the flow of the hydraulic fluid from the brake cylinder 56 to the master cylinder 14 and the pump 74 is blocked, thereby realizing a state in which the brake cylinder hydraulic pressure is maintained. I do. A bypass passage 102 is connected to each holding valve 100, and a bypass valve 104 for returning hydraulic fluid is provided in each bypass passage 102 as a check valve.

The portion of each branch passage 68 between the holding valve 100 and the brake cylinder 56 extends from the reservoir passage 106
Extend to the reservoir 108. In the middle of each reservoir passage 106, a pressure reducing valve 110, which is a normally closed electromagnetic on-off valve, is provided.
Is provided. The pressure reducing valve 110 is excited to be in an open state, in which state the flow of the hydraulic fluid from the brake cylinder 56 to the reservoir 108 is allowed, and
A state in which the brake cylinder fluid pressure is reduced is realized.

The reservoir 108 is formed by fitting a reservoir piston 112 to the housing in a substantially airtight and slidable manner, and the working fluid is formed in a reservoir chamber 114 formed in front of the reservoir piston 112 by the fitting. Is stored under pressure by a spring 116 as an urging means. The reservoir chamber 114 is connected to the main liquid passage 64 by the pump passage 72.

The pump passage 72 is partitioned into a suction passage 120 and a discharge passage 122 by a pump 74. The passages 120 and 122 are provided with a suction valve 124 and a discharge valve 126, both of which are check valves. Have been. In the pump passage 72, a damper chamber 128 and an orifice (not shown) are further provided in series with each other on the discharge side of the pump 74, whereby pulsation of the pump 74 is reduced.

A portion of the suction passage 120 between the suction valve 124 and the reservoir 108 is formed by a supply passage 130 through the master cylinder 14 and the pressure control valve 70 of the main liquid passage 64.
And is connected to the part between. In the middle of the supply passage 130, an inflow control valve 132 as an electromagnetic supply control valve is provided. The inflow control valve 132 is a normally closed electromagnetic on-off valve, and is closed (O) when the solenoid is excited.
FF: The supply is stopped (ON: supply state). Supply passage 130 out of suction passage 120
A check valve 1 is provided at a portion between the connection point of
34 are provided. The check valve 134 is provided to prevent the hydraulic fluid from flowing into the reservoir 108 from the master cylinder 14 when the flow control valve 132 is open. Therefore, the check valve 134 guarantees that the hydraulic fluid from the master cylinder 14 is sucked into the pump 74 at a high pressure. The reservoir passage 10
6 is the check valve 134 and the reservoir 10 of the suction passage 120.
8 is connected. Also, the suction passage 120
A sub-supply passage 140 extending from the master reservoir 136 is also connected between the two check valves 124 and 134. In the middle of the auxiliary supply passage 140, an auxiliary inflow control valve 142 and a check valve 144 are arranged in series.

As described above, both the master cylinder 12 and the master reservoir 136 are connected to the suction side of the pump 74 via the supply passage 130 and the sub-supply passage 140, respectively. In the traction control and the vehicle stability control, the hydraulic fluid is supplied from the master reservoir 136 via the auxiliary supply passage 140, and in the effectiveness characteristic control, the hydraulic fluid is supplied from the supply passage 130. The hydraulic pressure of the brake cylinder 56 is
If the hydraulic pressure of the master cylinder 12 is controlled to be higher than the hydraulic pressure of
When the hydraulic pressure of the brake cylinder 56 is controlled to the same height, the energy consumption of the pump 74 can be reduced. When the hydraulic fluid is supplied from the master cylinder 14 via the supply passage 130, the inflow control valve 132 is opened and the auxiliary inflow control valve 142 is closed. When the hydraulic fluid is supplied from the master reservoir 136 via the auxiliary supply passage 140, the inflow control valve 132 is closed and the inflow control valve 142 is opened.

The provision of the auxiliary supply passage 140 also has the advantage that a large amount of hydraulic fluid can be quickly supplied to the pump 74. Since the hydraulic pressure of the master cylinder 12 is high, the supply passage 130 needs to be a relatively thin tube having high strength, and since there is a restriction between the master reservoir 136 and the master cylinder 12, Cylinder 1
It is difficult to supply a large amount of the second working fluid to the pump 74 immediately. In contrast, the master reservoir 136
Since the hydraulic pressure is close to the atmospheric pressure, the auxiliary supply passage 140 can be, for example, a thick rubber tube or the like, and a large amount of hydraulic fluid can be supplied promptly.

The check valve 144 includes the inflow control valves 142 and 13
2 are both open, the master cylinder 12
This is provided in order to prevent the hydraulic fluid from flowing out to the master reservoir 136. Two inflow control valves 13
It is inherently not possible to open both of the switches 2 and 142. For example, one of the switches cannot be switched to the closed state while the other is kept in the open state, and the other is not opened by the electric control. Is changed, the master cylinder 12 may be communicated with the master reservoir 136 in some cases. The check valve 144 is provided in the supply passage 140 on the front wheel side because securing the braking force on the front wheel side is more important than securing the braking force on the rear wheel side. Note that the check valve 144 may be provided also in the supply passage on the rear wheel side. Since the hydraulic system on the rear wheel side is the same as the hydraulic system on the front wheel side, the same reference numerals are given and the description is omitted.

The hardware configuration of the brake device has been described above. Next, the software configuration will be described with reference to FIG. However, FIG. 4 representatively shows only a portion related to the front wheel brake system in the software configuration. This brake device includes a hydraulic pressure control device 180 mainly composed of a computer. Hydraulic pressure control device 1
80 is a CPU 182, a ROM 184, a RAM 186,
The computer mainly includes an input unit 188, an output unit 190, and the like. The ROM 184 stores an effect characteristic control (pressure control valve control) routine, an inflow control valve control routine, an antilock control routine, and the like. Each of these routines is executed by the CPU 182 while using the RAM 186, thereby executing the effect characteristic control, the inflow control valve control, and the like.

"Effective characteristic control" is performed so that the vehicle body deceleration G and the vehicle body deceleration G are increased so that the vehicle body deceleration G increases at the same gradient with respect to the brake operation force f despite the reduced capacity of the vacuum booster 12. Control of the braking effectiveness characteristic, which is the relationship with Since the control is also a control for assisting the braking force when the booster 12 reaches the assisting limit, it can be referred to as a braking force assisting control. Further, since the boosting factor is controlled, it can be referred to as boosting control.

The input unit 188 of the hydraulic pressure control device 180 includes:
Master cylinder hydraulic pressure sensor 202, wheel speed sensor 204
Etc. are connected. Master cylinder pressure sensor 202
Is provided in the master cylinder 14 or a portion that contains a hydraulic fluid having the same pressure as the master cylinder 14, and outputs a master cylinder hydraulic pressure signal. Since a hydraulic pressure corresponding to the operation amount of the brake pedal 10 is generated in the master cylinder 12, the brake operation amount can be obtained from the master cylinder hydraulic pressure. In the present embodiment, the master cylinder hydraulic pressure sensor 202 is provided as a brake operation force detection device that detects a brake operation force. The wheel speed sensor 204 is provided for each wheel, and outputs a wheel speed signal of each wheel. The braking slip state based on the wheel speed of each wheel,
Wheel acceleration and the like are determined, and antilock control and the like are performed based on the wheel acceleration and the like.

On the other hand, the output unit 190 of the hydraulic pressure control device 180
Is connected to the motor controller 208. The pump motor 76 is connected to the motor controller 208 via a drive circuit (not shown). Pump motor 7
6 is controlled by a drive circuit based on a command from the motor controller 208. The output unit 190 is further connected to a solenoid 84 of the pressure control valve 70 via a drive circuit 210, and the holding valve 100, the pressure reducing valve 110
The solenoid 212 and the solenoids 214 and 215 of the inflow control valve 132 and the sub inflow control valve 142
16 are connected. A current control signal for linearly controlling the magnetic force of the solenoid 84 is output to the drive circuit 210 of the solenoid 84 of the pressure control valve 70,
Holding valve 100, pressure reducing valve 110 and inflow control valve 132,
Each solenoid 212, 214, 2 of the sub-inflow control valve 142
The solenoids are turned on for the 15 drive circuits 216, respectively.
An ON / OFF drive signal for performing the / OFF drive is output.

The case where the effectiveness characteristic control is performed in the present brake device will be described. In the present embodiment,
As shown in FIG. 6, when the vacuum booster 12 reaches the assisting limit, the pressure increase of the brake cylinder 56 by the pump 74 is started. That is, (a boosting limit pressure, hereinafter referred to as the start pressure) master cylinder pressure P _MO when the master cylinder pressure P _M is the booster 12 has reached the boosting limit if reached, pressure increase is started Because
As target brake cylinder pressure P _B represented by a dashed line is obtained, the assisting pressure is applied. Figure 7 shows the relationship between the assisting pressure (target pressure difference) [Delta] P and the master cylinder pressure P _M. From FIG. 6, if the actual master cylinder hydraulic pressure is determined, the assisting pressure ΔP is determined. In other words, the control may be performed based on the master cylinder fluid pressure without being based on the brake cylinder fluid pressure.
By controlling the pressure control valve 70 so as to obtain the following equation, the brake cylinder hydraulic pressure can be made closer to the hydraulic pressure when the brake operating force is boosted at a constant boosting factor. In addition,
In the present embodiment, an upper limit of the assisting pressure is provided. This prevents the brake cylinder fluid pressure from becoming unnecessarily large. When the master cylinder pressure is equal to or higher than the set pressure P1, the assisting pressure is kept constant.
Even if the master cylinder hydraulic pressure is changed with the operation of 0, the assisting pressure is not changed. FIG. 8 shows the relationship between the target differential pressure ΔP and the solenoid current value I. The relationship between the target differential pressure ΔP and the solenoid current value I is determined based on the relationship between the target differential pressure ΔP and the solenoid attraction force F ₁ and the relationship between the solenoid attraction force F ₁ and the solenoid current value I. As described above, when the target differential pressure ΔP is equal to or higher than the differential pressure ΔP2 corresponding to the set pressure P1 of the master cylinder, the current supplied to the pressure control valve 70 is kept constant.

Routine represented by the flowchart of FIG.
Indicates that the vehicle's ignition switch is ON by the driver
It is executed repeatedly after being operated in the state. Step S1
(Hereinafter, simply represented by “S1.”
The same applies), the master cylinder pressure sensor 20
2 receives the master cylinder pressure signal, and goes to S2.
And the master cylinder indicated by the master cylinder pressure signal
Hydraulic pressure P_MIs the starting pressure P _M0It is determined whether it is higher.
Master cylinder pressure P_MIs the starting pressure P_M0If higher,
The determination is YES, and in S3, the brake cylinder
Hydraulic pressure P_BIs the master cylinder pressure P_MMeasures to increase
That is, the target differential pressure ΔP is calculated. Master cylinder pressure
P_MAnd the target pressure difference ΔP (for example, as shown in FIG. 7)
Relation) is stored in the ROM, and
Master cylinder pressure P according to the relationship_MCorresponding to the current value of
The target differential pressure ΔP is calculated. In S4,
Solving of the pressure control valve 70 according to the calculated target differential pressure ΔP
The supply current I to the solenoid 84 is obtained by calculation,
The change amount ΔI of the supply current is obtained. And pressure control
The current control of the solenoid 84 of the valve 70 is performed. This implementation
In the embodiment, the current control signal is applied to the solenoid 84.
This is a signal representing the change amount ΔI of the supply current. Target differential pressure Δ
The relationship between P and the solenoid current value I (for example, as shown in FIG.
Relation) is stored in the ROM, and in principle, the relation
The current value I corresponding to the target differential pressure ΔP is calculated according to
And the current change amount ΔI is obtained.
When the set condition is satisfied, the current change ΔI ′
Is made smaller than in the case described above. And pressure
The supply current to the solenoid 84 of the force control valve 70 changes
Current control is performed by changing the
Is Next, in S5, the inflow control valve 132 is turned on.
/ OFF control, and in S6, the pump motor 76
Actuated.

The control of the pressure control valve 70 in S4 will be described with reference to the graph of FIG. The master cylinder pressure is increased with an increase in the brake operating force, and the starting pressure P _MO
, The effect characteristic control is started (→). The assisting pressure ΔP increases as the master cylinder pressure increases, and the supply current I increases accordingly. When the effect characteristic control is started and increased first, the effect characteristic control with a normal gradient (hereinafter, referred to as normal gradient control) is performed. That is, the variation ΔI of the supply current I determined based on the relationship shown in FIG.
Is output (). Since an upper limit is set for the assisting pressure, as shown in FIG. 7, even if the master cylinder hydraulic pressure becomes higher than the set pressure P1, the assisting pressure is prevented from becoming ΔP2 or more. Also, in the region where the master cylinder hydraulic pressure is higher than the hydraulic pressure P1, the amount of current supplied to the pressure control valve 70 is kept constant even if the master cylinder hydraulic pressure changes.

As the brake operation amount decreases, the master cylinder hydraulic pressure decreases, and when the master cylinder hydraulic pressure falls below the set pressure P1, the supply current to the pressure control valve 70 is reduced. And than the suction force F ₁ is smaller, whereby the outflow of the working fluid from the brake cylinder side to the master cylinder side is allowed. In the present embodiment, the amount of decrease in the supply current is made smaller than the gradient determined based on the relationship in FIG. For example, in FIGS. 7 and 8, the master cylinder hydraulic pressure is the hydraulic pressure P _X
It is assumed that was reduced to the hydraulic pressure P _Y from. The supporting pressure is Δ
The amount of change ΔI of the supply current that decreases from P _X to ΔP _Y and should be reduced accordingly is ΔI = I _X −I _Y ,
In the present embodiment, since the gradient suppression control is performed,
The change amount ΔI ′ is obtained by multiplying the normal current change amount ΔI by a coefficient k smaller than 1 (ΔI × k) ｛= (I _X −I _Y ) ×
k｝. In this way, if the amount of decrease in the supply current I is suppressed, the pressure reduction gradient of the brake cylinder hydraulic pressure is suppressed. In the pressure control valve 70, the opening area (opening) of the opening between the valve element 80 and the valve seat 82 is suppressed, and the flow rate of the working fluid flowing through the pressure control valve 70 is suppressed. As a result, the flow rate of the working fluid flowing into the master cylinder 12 can be suppressed (). This control is referred to as gradient suppression control. The gradient suppression control can also be referred to as a flow rate reduction control.

Next, the control is switched to the pressure increasing control by increasing the brake operating force. In this case as well, similarly to the case where the pressure reducing control is performed, the variation ΔI of the supply current is suppressed. The opening of the pressure control valve 70 is not suddenly decreased, but is decreased slowly. If the pressure increase gradient is suppressed, the outflow rate from the master cylinder 12 can be suppressed (). When the pressure increase control time is longer than the outflow flow rate suppression allowable time T _UP ,
It is returned to the normal change amount. This is because it is desirable to increase the brake cylinder fluid pressure in order to satisfy the driver's braking demand. The amount of supply current is reduced with a decrease in the brake operating force. In this case as well, the pressure reduction gradient is suppressed as in the case of (2).
When the master cylinder hydraulic pressure becomes equal to or lower than the start pressure _PMO with a decrease in the brake operation force, the effectiveness characteristic control is ended. In S7 and S8, the solenoid 8 of the pressure control valve 70
4. The solenoid 214 of the inflow control valve 132 is turned off, and in S9, the pump motor 76 is stopped.

As described above, in the present embodiment, when the master cylinder hydraulic pressure is equal to or higher than the set pressure P1, the master cylinder hydraulic pressure is equal to or lower than the set pressure P1, and when the initial pressure increase is not performed, When the elapsed time is within the outflow flow rate suppression allowable time, the gradient suppression control (flow rate reduction control) is performed, and is not always performed. If the actual braking force change speed can be smaller than the driver's required braking force change speed, that is, if the master cylinder hydraulic pressure is equal to or higher than the set pressure or if the required brake change speed is equal to or less than the set speed, the pressure control is performed. The amount of change in the supply current of the valve 70 is reduced. At the time of pressure reduction control, the flow rate of the working fluid flowing through the pressure control valve 70 is suppressed, and at the time of pressure increase control, the flow rate is made larger. As a result, the flow rate into the master cylinder during pressure reduction control can be suppressed. Since the increase gradient due to the reaction force applied to the brake pedal 10 is suppressed, the increase gradient of the driver's brake operation force can be suppressed, and the increase gradient of the master cylinder hydraulic pressure can be suppressed. The influence of the increase in the master cylinder hydraulic pressure accompanying the increase in the reaction force can be reduced, the disturbance can be reduced, and the control hunting can be suppressed. Similarly, since the outflow rate from the master cylinder during the pressure increase control can be suppressed, the influence of the decrease in the master cylinder hydraulic pressure due to the decrease in the reaction force can be reduced. Also,
When the driver's braking force request change speed is high, the gradient suppression control is not performed, so that the braking force can be changed at a speed according to the driver's intention.

In the above embodiment, both the inflow flow rate and the outflow flow rate are suppressed, but it is not essential to suppress the outflow flow rate. This is because if the brake pedal 10 enters with a decrease in the reaction force and the brake operation force is kept substantially constant accordingly, the influence on the decrease gradient of the master cylinder hydraulic pressure is not so large. Further, not only during the pressure increase control but also during the pressure reduction control, when the elapsed time from the start of the pressure reduction becomes equal to or longer than the inflow flow rate suppression allowable time, the gradient suppression control can be switched to the normal gradient control. Can also. Conversely, it is not indispensable to switch to the normal gradient control when the elapsed time of the pressure increase time or the pressure decrease time exceeds the set time. Further, the hydraulic pressure of the brake cylinder 56 can be reduced by setting the pressure reducing valve 110 to the communicating state. For example, if the working fluid flows out through the pressure reducing valve 110 only at the time of rapid pressure reduction, it is possible to avoid an excessive flow rate of the fluid flowing into the master cylinder 12. Further, the effect characteristic control is not limited to the above-described mode, and can be executed in another mode. For example, the starting pressure _PM0 may be a value after the booster 12 has reached the assisting limit or a value before reaching the assisting limit. Further, the structure of the booster 12 is not limited to that in the above embodiment, and may be a structure in which the boost factor changes before reaching the assisting limit. Regarding the structure of this booster and the control of its effectiveness characteristics, see Japanese Patent Application No. 10-8383.
Are described in detail in the specification, and the description is omitted.

Next, the inflow control valve 13 in S5 described above.
Control 2 will be described with reference to the flowchart of FIG. The inflow control valve 132 is kept at the original position (closed state) as shown in the drawing while the effectiveness characteristic control is not being performed, but is kept in the open state (ON) during the effectiveness characteristic control in principle. However, in the present embodiment, the open state is not always maintained, and the state is switched to the closed state (OFF) when a predetermined condition is satisfied. Thereby, the main liquid passage 64 is sucked by the pump 74 and
The amount of hydraulic fluid returned to the master cylinder 12 can be reduced, and the flow rate of inflow returned to the master cylinder 12 can be suppressed. As described above, the pressure control valve 70 controls the pressure difference between the master cylinder side and the brake cylinder side to a magnitude corresponding to the supply current. Therefore, even when the pressure reduction control is not performed, if the hydraulic fluid is discharged from the pump 74 and returned to the main fluid passage 64, the hydraulic pressure on the brake cylinder side increases, thereby increasing the hydraulic pressure on the master cylinder side. If the difference is larger than the pressure difference corresponding to the supply current, the hydraulic fluid is returned to the master cylinder 12 via the pressure control valve 70. Therefore, when it is not necessary to supply the hydraulic fluid to the brake cylinder 56, by switching the inflow control valve 132 to the closed state, the inflow flow rate of the hydraulic fluid returned to the master cylinder 12 can be suppressed.

In the present embodiment, the inflow control valve 132 is switched to the closed state when the driver's braking increase request is small. When the inflow control valve 132 is in the open state (ON state) and the change amount ΔF of the master cylinder hydraulic pressure is smaller than the set change amount α1 (suppression switching threshold α1), the closed state (OFF state). Is switched to. In the closed state, the closed state is maintained while the change amount ΔF of the master cylinder hydraulic pressure is smaller than a predetermined set change amount α2 (suppression maintaining threshold value α2). When it is equal to or greater than the threshold value α2, the state is switched to the open state. Further, these threshold values α1 and α2 are not always constant, but are determined based on the immediately preceding OFF state time or ON state time. The suppression maintaining threshold value α2 is larger than the suppression switching threshold value α1.

The inflow control valve 132 in the ON state is turned off.
The threshold value α1 for suppression switching for switching to the state
It is determined based on the OFF time immediately before the inflow control valve 132 is switched. As the immediately preceding OFF time is shorter, the suppression switching threshold value α1 is increased, and the switching to the OFF state is facilitated. Set the inflow control valve 132 in the OFF state to O
Threshold α2 for suppression maintenance whether to switch to N state
Is determined based on the immediately preceding ON time. As the ON time is shorter, the suppression maintaining threshold value α2 is increased, and it is difficult to maintain the ON state. In other words, it is easy to switch to the OFF state.
The N, OFF time makes it easier for the inflow control valve 132 to be kept in the OFF state.

In step S101, the inflow control valve 132
It is determined whether the state has been switched between the N state and the OFF state. If the switch has been made, the determination is YES, and in S102, it is determined whether the state after the switch is the ON state. If it is ON, S
103 and subsequent steps are executed. The immediately preceding OFF time is read, and the suppression switching threshold α1 is determined based on the OFF time in accordance with a predetermined table. As described above, the shorter the OFF time, the larger the suppression switching threshold value α1 is determined. Then, in S104, it is determined whether or not the amount of change in the master cylinder hydraulic pressure is smaller than the suppression switching threshold value α1. If it is smaller than the suppression switching threshold α1, it is switched to the OFF state in S105, and if it is more than the suppression switching threshold α1, it is kept ON in S106. If the braking increase request is small, the state is switched to the OFF state, and if the braking request is large, the state is switched to the ON state.

If the state after the switching is the OFF state, the immediately preceding ON time is read in S107, and the suppression maintaining threshold α2 is determined. The suppression maintaining threshold value α2 is increased as the ON time is shorter, similarly to the suppression switching threshold value α1. In S108, the variation ΔF of the master cylinder hydraulic pressure is
It is determined whether it is greater than. ON if larger
The state is switched to the OFF state, but when the state is small, the OFF state is maintained. On the other hand, if the state of the inflow control valve 132 does not switch, the determination in S101 is NO, and in S111, it is determined whether the current state is the ON state. If it is ON, S104 and subsequent steps are executed, and if it is OFF, S108 and subsequent steps are executed.

With this control, the inflow control valve 132 is turned off as long as the driver's braking increase request is small.
Since the state is maintained, the inflow flow rate returned to the master cylinder 12 via the pressure control valve 70 can be suppressed, and control hunting can be suppressed. Further, by switching to the OFF state, energy consumption can be reduced. Furthermore, by setting it to the OFF state (closed state), it is also possible to suppress the amount of hydraulic fluid flowing out of the master cylinder 12.

In the above embodiment, the suppression switching threshold value α1 and the suppression maintaining threshold value α2 are set to ON immediately before.
The value is set to a larger value as the time or OFF time is shorter, but may be increased stepwise as the ON time or OFF time becomes shorter. Further, it can be determined based on the elapsed time after the immediately preceding switching of the inflow control valve 132. While the elapsed time after the switching is short, the state is maintained, that is, the switching is difficult. If the elapsed time after switching from the OFF state to the ON state is short, the suppression switching threshold α1 is reduced. If the elapsed time after switching from the ON state to the OFF state is short,
The suppression maintaining threshold value α2 is increased. Also,
If the elapsed time after the switching is within a predetermined set time, the switching itself of the inflow control valve 132 may be prohibited. It is not essential to provide both the threshold values α1 and α2. When the value is smaller than the threshold value, the inflow control valve 132 is closed, and when the value is larger than the threshold value, it is switched to the open state.

Further, by controlling the operation state of the pump 74, at least one of the inflow flow rate and the outflow flow rate can be suppressed. When the braking increase request is small, the number of revolutions is reduced and the discharge amount of the pump 74 is reduced. Thereby, the amount of the working fluid supplied to the main liquid passage 64 can be reduced, and the inflow flow rate can be reduced. In addition, since the suction amount of the pump 74 is suppressed, the amount of hydraulic fluid that flows out of the master cylinder can be reduced.

As described above, according to the present embodiment, the control valve device control device is constituted by the portion for controlling the pressure control valve 70 of the hydraulic control device 180, the solenoid 84, and the like. Further, S4 and S5 of the effectiveness characteristic control routine (S103, 104, 105 and 107 of the inflow control valve control routine) shown in the flowchart of FIG.
108, 110) constitute a flow rate reduction device. Among them, the part that executes S4, the part that stores the pressure-reducing gradient among the parts that store it, and the like constitute an inflow-flow-rate suppressing unit and an opening-degree suppressing unit.
5 constitutes a discharge amount suppressing section and a supply amount suppressing device. The supply control device is a conditional supply control device. Also, a part for executing S103 and S107,
The storage request part and the like constitute a setting request degree determination unit. Also, of the above-described discharge suppressing unit, the part that stores S4, and the part that executes S4, the part that suppresses the pressure increase gradient and the like is also an outflow flow rate reducing device. In the present embodiment,
Control valve device By part of the control device,
Although the opening degree suppression unit is configured, the inflow flow rate suppression unit and the opening degree suppression unit can be configured separately from the control valve device control device.

As the flow rate reduction control, the pressure control valve 7
It is not necessary to perform both the control of 0 and the control of the inflow control valve 132, and only one of them may be performed. Further, the structure of the brake device is not limited to the above-described embodiment, and may be another structure. For example, the pressure control valve 70 may be a simple electromagnetic valve. In this case, the hydraulic pressure of the brake cylinder 56 can be controlled by switching the electromagnetic on-off valve between the open state and the closed state. Further, the inflow control valve 132 may be an electromagnetic flow control valve whose flow rate is allowed according to the supply current. In this case, by reducing the supply current, the flow rate of the working fluid flowing through the electromagnetic flow control valve is suppressed, whereby the outflow flow rate in the master cylinder 12 is suppressed. In addition, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in [Problems to be Solved by the Invention, Problem Solving Means and Effects].

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a brake device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a pressure control valve included in the brake device.

FIG. 3 is a diagram showing a relationship between a supply current to the pressure control valve and a solenoid attraction force.

FIG. 4 is a diagram illustrating a periphery of a hydraulic control device of the brake device.

FIG. 5 is a flowchart showing an effectiveness characteristic control program stored in a ROM of the hydraulic control device.

FIG. 6 is a diagram showing a relationship between a brake operation force controlled by the hydraulic pressure control device and a brake cylinder hydraulic pressure.

FIG. 7 is a diagram showing a relationship between a master cylinder hydraulic pressure controlled by the hydraulic pressure control device and an assisting force (target differential pressure).

FIG. 8 is a diagram showing a relationship between a supply current I to a pressure control valve controlled by the hydraulic pressure control device and a target differential pressure.

FIG. 9 is a diagram illustrating an example of control by the hydraulic pressure control device.

FIG. 10 is a flowchart showing a part of the effect characteristic control program (flow control valve control program).

FIG. 11 is a diagram for explaining a control problem in a conventional brake device.

[Explanation of symbols]

 12 Master cylinder 56 Brake cylinder 70 Pressure control valve 74 Pump 76 Pump motor 78 Pressurizing device 84 Solenoid 132 Inflow control valve 180 Fluid pressure control device 202 Master cylinder fluid pressure sensor

Claims (9)

[Claims] 1. A brake cylinder for operating a brake by a hydraulic pressure, a master cylinder for generating a hydraulic pressure in accordance with an operating force of a brake operating member, and a master hydraulic passage connecting the brake cylinder and the master cylinder. A control valve device provided to control a communication state between the brake cylinder and the master cylinder, a control valve device control device to control the control valve device according to a predetermined rule, and a hydraulic fluid supplied from a hydraulic fluid supply device A pressurizing device that pressurizes the main fluid passage and supplies the main fluid passage from the control valve device to a portion closer to the brake cylinder. If the device is controlled in accordance with the rules by the control valve device control device, the corresponding outflow and inflow flow rates are reduced. Brake device characterized by including a flow reduction apparatus for reducing than one. 2. A brake cylinder for operating a brake by a hydraulic pressure, a master cylinder for generating a hydraulic pressure in accordance with an operating force of a brake operating member, and a brake for pressurizing hydraulic fluid supplied from a hydraulic fluid supply device. A pressurizing device for supplying a main fluid passage connecting a cylinder and the master cylinder; and a brake cylinder side provided on the master cylinder side from a portion of the main fluid passage where hydraulic fluid is supplied by the pressurizing device. A control valve device that allows the flow of hydraulic fluid from the valve to the master cylinder side at a flow rate corresponding to the supplied electric energy, and controls the supplied electric energy to the control valve device based at least on the operating force of the brake operating member. A control valve device control device, wherein the control valve device controls the inflow flow rate of the working fluid flowing into the master cylinder via the control valve device. Brake system which comprises a flow reducing device for reducing than the inflow rate when controlled by a valve device controller. 3. The flow rate reduction device according to claim 1, wherein the control valve device controls the flow rate of the hydraulic fluid flowing into the master cylinder. 3. The brake device according to 2. 4. The control valve device includes an electromagnetic flow control valve that allows a flow of hydraulic fluid from a brake cylinder side to a master cylinder side at an opening degree according to supplied electric energy, The brake device according to claim 3, further comprising an opening suppression unit that suppresses an opening of the electromagnetic flow control valve. 5. The brake device according to claim 1, wherein the flow rate reducing device includes a discharge amount suppressing unit that suppresses a discharge amount of the working fluid of the pressurizing device. . 6. The apparatus according to claim 1, wherein said flow rate reducing device includes a supply amount suppressing device for suppressing a supply amount of the working fluid supplied from said working fluid supply device to said pressurizing device. The brake device according to any one of the above. 7. A conditional supply for suppressing the supply amount of the hydraulic fluid when the driver's request for increasing the brake cylinder hydraulic pressure is lower than a predetermined request degree. The brake device according to claim 6, wherein the brake device is a quantity suppression device. 8. A setting request degree determining unit for determining the setting request degree based on a past control state by the conditional supply amount suppressing apparatus, wherein the setting request degree determining unit determines the setting request degree. The brake device according to claim 7, wherein the supply amount is suppressed when a degree of the pressure increase request is smaller than a set request degree determined by the unit. 9. The hydraulic fluid supply device is the master cylinder, the pressurizing device is a pump device that pressurizes hydraulic fluid supplied from the master cylinder, and the flow rate reducing device is a pump device. The brake device according to any one of claims 1 to 8, further comprising an outflow flow rate reduction device that reduces an outflow flow rate of the hydraulic fluid that flows out of the master cylinder for supplying the hydraulic fluid to the master cylinder.