JP2003252189A - Brake fluid pressure controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit the vibration of an intensification control valve and a decompression control valve in a brake fluid pressure controller. <P>SOLUTION: In the case when the operation of an accelerator pedal is released in a non-operating condition of a brake pedal, the fluid pressure of a brake cylinder is intensified and held to a degree to keep a frictional engagement member at a position near a brake rotating body. Whereby, a clearance between a brake pad and the brake rotating body is reduced. When the brake pedal is actually pressed, the fluid pressure of the brake cylinder is controlled to the pressure in accordance with a brake operating condition by controlling a pressure intensifying linear valve. Here as the clearance is reduced, a flow rate and the amount of the operating fluid flowing in the intensification linear valve can be reduced, and the vibration can be inhibited. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake hydraulic pressure control device, and more particularly to control of a hydraulic pressure control valve.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 5-170075 discloses
(a) a pressure increase control valve provided between a brake cylinder of a brake operated by hydraulic pressure and a high pressure source, and (b) a pressure reduction control valve provided between the brake cylinder and a low pressure source, (c) A brake fluid pressure control device including a control device that controls at least one of the pressure increase control valve and the pressure reduction control valve so that the fluid pressure of the brake cylinder becomes a desired magnitude is described. . In this brake fluid pressure control device, the control device divides the command signal at the time of opening the pressure increase control valve and the pressure reduction control valve into two and outputs them. Thereby, the vibration of the pressure increase control valve and the pressure reduction control valve can be suppressed.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention, Means for Solving the Problems and Effects of the Invention An object of the present invention is to make it possible to suppress the vibrations of the pressure increasing control valve and the pressure reducing control valve by means different from the means described in the above publication. It is to be. This problem is solved by using a brake fluid pressure control device having the configuration of each of the following aspects. Similar to the claims, each mode is divided into paragraphs, each paragraph is given a number, and the numbers of other paragraphs are referred to as necessary. This is merely for facilitating the understanding of the technology described in the present specification, and it should not be construed that the technical features described in the present specification and a combination thereof are limited to the following items. Absent. Further, when a plurality of items are described in one section, it is not always necessary to adopt all the items together, and it is possible to take out only some of the items and adopt them.

Of the following items, (1) corresponds to claim 1, (4) corresponds to claim 2, (6) corresponds to claim 3, and (8). , (12) corresponds to claims 4 and 5. The item (15) corresponds to claim 6, and the first control unit in item (19) corresponds to claim 7.

(1) A pressure increasing control valve provided between a high pressure source and a brake cylinder of a brake operated by hydraulic pressure, and a pressure reducing control valve provided between the brake cylinder and a low pressure source. A control device for controlling the hydraulic pressure of the brake cylinder by controlling at least one of the pressure increasing control valve and the pressure reducing control valve, and the control device controls the hydraulic pressure of the brake cylinder to a desired magnitude. Before starting control of at least one of the main control unit and the pressure increasing control valve and the pressure reducing control valve by the main control unit, the flow rate of the hydraulic fluid flowing through at least one of the main control unit at the start of control is A brake fluid pressure control device, comprising: an auxiliary control unit that controls the state of the brake cylinder so as to be smaller than that when the control is not performed. In the brake fluid pressure control device according to this section, the control by the main control unit is performed after the control by the auxiliary control unit. Since the auxiliary control unit controls the state of the brake cylinder (fluid pressure, piston position, etc.) so that the flow rate of the hydraulic fluid flowing through the pressure increasing control valve or the pressure reducing control valve is reduced when the main control unit starts the control, It is possible to suppress the flow rate of the pressure increasing control valve and the pressure reducing control valve at the start of control by the main control unit, and it is possible to suppress self-excited vibration of the pressure increasing control valve and the pressure reducing control valve. The main controller controls at least one of the pressure increasing control valve and the pressure reducing control valve so that the hydraulic pressure of the brake cylinder becomes a desired value. The desired size can be determined based on the state of the vehicle, for example. The size determined based on the driver's operating state of the operating member such as the brake operating member provided on the vehicle (the size according to the driver's request), the braking slip state,
The size may be determined based on the running state of the vehicle such as the drive slip state and the turning state. The hydraulic pressure of the brake cylinder is controlled to a size that satisfies the driver's request or a size suitable for the running state of the vehicle. The hydraulic pressure of the brake cylinder is controlled by a braking effect control means, an antilock control means, a traction control means, a vehicle stability control means, etc., and these control means are one mode of the main control section. The main control unit determines the target hydraulic pressure of the brake cylinder and controls it so that the hydraulic pressure of the brake cylinder becomes the target hydraulic pressure, or the running state such as the slip state becomes the desired state. The case is applicable. In any case, it can be considered that the hydraulic pressure in the brake cylinder is controlled to a desired magnitude. The control by the auxiliary control unit is performed before the main control unit starts control of at least one of the pressure increase control valve and the pressure reduction control valve. The auxiliary control unit controls the state of the brake cylinder so that the flow rate of the hydraulic fluid flowing through at least one of the pressure increase control valve and the pressure reduction control valve becomes small when the control by the main control unit is started. For example, the boost control valve,
If the pressure reducing control valve allows the flow of hydraulic fluid at a flow rate that is determined based on the current supplied to the solenoid and the differential pressure between the front and rear, if the differential pressure before and after is set small in advance, the main control unit The flow rate of the hydraulic fluid flowing through the pressure increase control valve and the pressure reduction control valve can be reduced with respect to the same current supplied. Also, by supplying hydraulic fluid to the brake cylinder,
If the brake clearance is made small, the amount of fluid consumed in the brake cylinder can be suppressed at the beginning of control by the main control unit, and the amount of hydraulic fluid flowing through the booster control valve at the beginning of control can be reduced. . Also from this point, the vibration of the pressure increase control valve can be suppressed. further,
There is also an advantage that the braking delay can be reduced and the operation response can be improved. The pressure increasing control valve and the pressure reducing control valve may have any structure, and include a valve seat (fixed member) and a valve element (movable member) that can approach and separate from the valve seat. The seating valve may include the seating valve, or the spool valve may include a housing (fixing member) and a spool that is relatively movably fitted to the housing and is linearly movable. In any case, it is an electromagnetic control valve that is operated by supplying a current to the solenoid. The pressure-increasing control valve and pressure-decreasing control valve are O of the current supplied to the solenoid.
Even with an electromagnetic opening / closing valve that can be switched between an open state and a closed state by N / OFF, the supply current to the solenoid can be continuously controlled, and an electromagnetic driving force corresponding to the supply current, It may be an electromagnetic linear control valve in which the relative position of the movable member with respect to the fixed member is determined based on the differential pressure acting force corresponding to the front-back differential pressure. The high-pressure source can be a power hydraulic pressure source that pressurizes the hydraulic fluid by a drive source that is driven by power supply, or a master cylinder that generates hydraulic pressure according to the operating force of the brake operating member. The master cylinder can also be a low pressure source. This is because hydraulic pressure is not generated in the master cylinder when the brake operating member is not operated. The low voltage source is
It can be a reservoir that keeps the hydraulic fluid at about atmospheric pressure. (2) The pressure-increasing control valve and the pressure-decreasing control valve allow the flow of the hydraulic fluid at a flow rate determined based on the current supplied to the solenoid and the differential pressure between the front and rear, respectively, and the main control unit The brake fluid pressure control device according to (1), wherein the auxiliary control unit and the auxiliary control unit each include a supply current control unit that controls a supply current to the solenoid. (3) The auxiliary control unit includes a differential pressure reducing unit that reduces the differential pressure before and after at least one of the pressure increasing control valve and the pressure reducing control valve by controlling the hydraulic pressure of the brake cylinder (1 ) Or the brake fluid pressure control device according to (2). For example, when the hydraulic pressure of the high-pressure source is almost constant and the pressure increase control valve is controlled by the main control unit, if the hydraulic pressure of the brake cylinder is increased by the auxiliary control unit, the pressure increase control valve Since the differential pressure between the front and back is small,
It is possible to reduce the flow rate of the hydraulic fluid flowing through the pressure increase control valve when the pressure increase control valve is controlled by the main control unit. When the pressure reduction control valve is controlled by the main control unit when the hydraulic pressure of the low pressure source is almost constant, if the hydraulic pressure of the brake cylinder is reduced by the auxiliary control unit, the differential pressure before and after the pressure reduction control valve is reduced. Since it becomes smaller, the flow rate of the hydraulic fluid flowing through the pressure reducing control valve can be made smaller.

(4) The brake suppresses the rotation of the wheel by pressing the friction engagement member against the brake rotating body that is rotated integrally with the wheel by the hydraulic pressure of the brake cylinder. The control unit includes a friction engagement member approaching unit that brings the friction engagement member closer to the brake rotating body by supplying hydraulic fluid to the brake cylinder (1) to (3). The brake fluid pressure control device according to one. By supplying the hydraulic fluid to the brake cylinder by the auxiliary control unit, the friction engagement member is brought close to the brake rotating body, and the clearance is reduced. If the clearance is reduced, the amount of hydraulic fluid consumed in the brake cylinder at the beginning of brake operation can be reduced, and the amount and flow rate of hydraulic fluid flowing through the pressure increase control valve can be reduced. As shown in FIG. 9, at the beginning of the brake operation, the amount of hydraulic fluid consumed in the brake cylinder (the amount of hydraulic fluid required to increase the hydraulic pressure by a unit pressure) increases. In the non-operating state of the brake, the friction engagement member is separated from the brake rotating body. Therefore, until the friction engagement member comes into contact with the brake rotating body, even if hydraulic fluid is supplied to the brake cylinder, the hydraulic pressure does not effectively increase,
The increasing gradient of the hydraulic pressure in the brake cylinder becomes smaller. When the friction engagement member comes into contact with the brake rotating body, a reaction force is generated from the brake rotation body to the friction engaging member, so that the increasing gradient of the brake cylinder hydraulic pressure becomes large. Therefore, if the clearance is reduced by the auxiliary control unit, the amount and flow rate of the hydraulic fluid flowing through the pressure increase control valve can be reduced at the beginning of operation of the brake, and vibration can be suppressed. In particular, if the clearance is made as small as possible within the range in which the friction engagement member does not come into contact with the brake rotating body, dragging can be prevented, which is effective. The beginning of the operation of the brake can be, for example, until the clearance becomes 0 and before the first fill is completed. However, although the frictional engagement member is actually pressed against the brake rotating body, the pressing force can be set to be within the set value.
As described above, until the brake clearance disappears, the hydraulic pressure in the brake cylinder does not effectively increase even if the hydraulic fluid is supplied, but it does not increase at all.
In order to bring the friction engagement member closer to the brake rotating body,
When it is necessary to overcome the frictional force between the supporting member such as the mounting bracket that supports it, and when a piston seal having a retraction function is provided between the piston of the brake cylinder and the cylinder housing. Requires some hydraulic pressure to elastically deform it. Further, as described above, when the "initial operation of the brake" is "the friction engagement member is in the state of being pressed against the brake rotating body, but the pressing force is within the set value or less", A hydraulic pressure corresponding to the pressing force is generated in the brake cylinder. Therefore, it is necessary to increase the hydraulic pressure of the brake cylinder to some extent in order to bring the friction engagement member closer to the brake rotating body.
It can be considered that the friction engagement member approaching portion causes the friction engagement member to approach the brake rotating body by controlling the hydraulic pressure of the brake cylinder. (5) Any one of (1) to (4), wherein the main control unit includes a pressure increase control valve control unit that increases the hydraulic pressure of the brake cylinder by controlling the pressure increase control valve. Brake fluid pressure control device described in. As described above, when the hydraulic fluid is supplied to the brake cylinder by the auxiliary control unit, the friction engagement member is brought close to the brake rotating body, and when the clearance is reduced, the hydraulic pressure of the brake cylinder is increased. Therefore, the differential pressure before and after the boost control valve is reduced,
When the pressure increasing control valve is controlled by the main controller, the flow rate of the hydraulic fluid flowing through the pressure increasing control valve can be reduced.

(6) Corresponding to the approach position where the friction engagement member approaching portion controls the hydraulic pressure of the brake cylinder as the state of the brake cylinder based on the relative position of the friction engagement member with respect to the brake rotating body. The brake fluid pressure control device according to item (4) or (5), including a fluid pressure control unit. The hydraulic pressure of the brake cylinder is controlled so that the relative position of the friction engagement member with respect to the brake rotating body becomes a predetermined position. It is desirable that the target relative position is a position where the friction engagement member is as close to the brake rotating body as possible and is not in contact with it. When the clearance is greater than 0 and is very small, dragging can be prevented and vibration at the start of control of the pressure increase control valve by the main control unit can be reduced. The target relative position may be a position where the friction engagement member actually abuts the brake rotating body. Even if these are in contact with each other, the contact force (that is, the pressing force of the friction engagement member by the brake cylinder)
If is less than or equal to the set value, the driver's discomfort is small. At the beginning of the brake operation, the frictional engagement member is advanced by the supply of the hydraulic fluid to the brake cylinder and is brought closer to the rotating body of the brake. If the piston seal having the retraction function is provided, the piston seal is elastically deformed and the pulling force of the piston is generated. The brake cylinder has
A hydraulic pressure is generated according to the elastic force of the piston seal. Therefore, based on the relative movement amount of the piston with respect to the brake cylinder, the elastic deformation amount of the piston seal can be estimated, and the hydraulic pressure of the brake cylinder can be estimated. The hydraulic pressure of the brake cylinder for the relative position of the friction engagement member to the brake rotating body to reach the target relative position can be obtained by design. Also,
When the friction engagement member is brought into contact with the brake rotating body, the hydraulic pressure of the brake cylinder is controlled so that the contact force has a magnitude that does not produce a braking effect that makes the driver feel uncomfortable. It In order to maintain the relative position of the friction engagement member with respect to the brake rotating body at the target relative position, it is desirable to maintain the hydraulic pressure of the brake cylinder. The hydraulic pressure in the brake cylinder is maintained by the auxiliary control unit until the control by the main control unit is started. However, it is not essential that the auxiliary control unit holds the hydraulic pressure of the brake cylinder until the control by the main control unit is started. The liquid pressure may be reduced. This is because the effect that the friction engagement member is brought close to the brake rotating body immediately before the control by the main control unit is not immediately lost by the above-mentioned pressure reduction. This point will be described in detail in connection with item (27).

(7) The auxiliary control section starts controlling the hydraulic pressure of the brake cylinder from a time point that is not related to the flow rate change cycle of the hydraulic fluid flowing through the at least one control valve under the control of the main control section. The brake fluid pressure control device according to any one of (1) to (6). For example, if the phase of the flow rate change of the hydraulic fluid flowing through the pressure increase control valve or the pressure reducing control valve under the control of the main control section and the phase of the flow rate change under the control of the auxiliary control section are opposite, the pulsation of the hydraulic fluid is suppressed. However, it is possible to suppress the vibration of the pressure increase control valve and the pressure reduction control valve,
The brake fluid pressure control device described in this section does not aim to suppress vibration by canceling these flow rate changes. (8) In the non-operation state of the brake, the auxiliary control unit does not request the operation of the brake by the main control unit,
And, in the near future, when there is a high possibility that a brake operation request will occur, the brake operation prediction control start part for starting the control of the hydraulic pressure of the brake cylinder is included (1) to (7) Brake fluid pressure control device according to any one of the above. The present items, (10), and (11) relate to the start timing of the control of the auxiliary control unit when suppressing the self-excited vibration of the pressure increase control valve. Control by the auxiliary control unit will be
The control is started when the auxiliary control start condition such as the possibility that the control by the main control unit is started is high.
In the brake fluid pressure control device according to this section, the auxiliary control start condition is that when the brake is not in operation, there is no brake operation request, but there is a high possibility that the brake will be operated in the near future, that is, brake operation. Satisfied when an event occurs that is expected to require a request. The brake may be actuated according to the operation of the brake operating member by the driver, or may be actuated based on the running state of the vehicle regardless of the operating state of the brake operating member. The brake operation request is generated when the brake operating member is operated, and when the traction control start condition, the vehicle stability control start condition, and the like are satisfied. Therefore, when the possibility that the driver operates the brake operating member becomes high, or when the possibility that traction control or vehicle stability control is started becomes high, a brake operation request will occur in the near future. It is considered highly likely. (9) Any one of the items (1) to (8), wherein the main control unit controls the hydraulic pressure of the brake cylinder so that the brake operation request is satisfied from the time when the brake operation request is generated. Brake fluid pressure control device described in.

(10) When the auxiliary control section starts the control of the hydraulic pressure of the brake cylinder at the time when the release of the operation of the accelerator operating member is detected in the non-operating state of the brake operating member, the accelerator operation is released. Including control start part
The brake fluid pressure control device according to any one of (1) to (9). (11) The main control unit includes a traveling state-corresponding hydraulic pressure control unit that controls the hydraulic pressure of the brake cylinder when the traveling state amount indicating the traveling state of the vehicle exceeds a control start threshold value.
The auxiliary control unit starts the control of the hydraulic pressure of the brake cylinder when the traveling state amount exceeds the predicted control start value smaller than the control start threshold value (1) to (1).
The brake fluid pressure control device according to any one of items 0).

(12) The auxiliary control section may include a pattern control section for controlling the hydraulic pressure of the brake cylinder in accordance with a predetermined set pattern. (1) to (11) Brake fluid pressure control device. The hydraulic pressure in the brake cylinder may be maintained at a substantially constant magnitude, or may be changed periodically or aperiodically. In any case, it is controlled according to a predetermined pattern. (13) The pattern control unit includes a pressure increasing / depressurizing unit for increasing and then decreasing the hydraulic pressure of the brake cylinder, and the pressure increasing / depressurizing unit is operated intermittently. Brake fluid pressure control device. For example, the hydraulic pressure of the brake cylinder may be increased or decreased at set intervals. As a result, compared with the case where the hydraulic pressure of the brake cylinder is maintained, it is possible to suppress the vibration of the control valve while reducing the energy consumption. For example, as described above, the effect that the friction engagement member is brought close to the rotating body of the brake does not immediately disappear due to the pressure reduction of the brake cylinder hydraulic pressure, so that the pressure increase / decrease unit also increases The vibration control effect of the pressure control valve can be obtained. (14) Any one of the items (1) to (13), wherein the auxiliary control unit terminates the control of the hydraulic pressure of the brake cylinder when the possibility that a brake actuation request will occur in the near future becomes low. Brake fluid pressure control device according to any one of the above. The control by the auxiliary control unit may be continuously performed until the control by the main control unit is started, or may be ended before the control by the main control unit is started. For example, if the braking operation demand is estimated to be not generated in the near future, the energy consumption amount is increased as compared with the case where the control is continuously performed until the control by the main control unit is started. Can be reduced. It has been determined that the set time has elapsed since the auxiliary control was started, and that the possibility that the brake operation member will be operated is extremely low (for example, the vehicle traveling speed has remained almost constant for more than the set time). ), It is possible that the brake operation request is unlikely to occur when at least one of the following conditions is satisfied: the vehicle is traveling straight ahead and the straight traveling state continues for a set time or longer.

(15) The auxiliary control unit includes a vehicle stop control start unit that starts controlling the hydraulic pressure of the brake cylinder when the traveling speed of the vehicle falls below a set speed due to the operation of the brake. The brake fluid pressure control device according to any one of (1) to (14), including the above. (16) The auxiliary control unit suppresses an increase in the hydraulic pressure of the brake cylinder when the operation state amount representing the operation state of the brake operating member is equal to or more than a set state amount (1) to (1)
The brake fluid pressure control device according to any one of (15). (17) The brake fluid according to any one of (1) to (16), wherein the main control unit includes a pressure reducing control unit that reduces the hydraulic pressure of the brake cylinder by controlling the pressure reducing control valve. Pressure control device. When the main controller reduces the hydraulic pressure in the brake cylinder, if the differential pressure across the pressure reducing control valve is large, the flow rate of the hydraulic fluid flowing through the pressure reducing control valve increases.
Therefore, if the differential pressure between the front and rear is reduced during depressurization, the flow rate of the hydraulic fluid flowing through the depressurization control valve can be reduced. The pressure reducing control valve is provided between the brake cylinder and the low pressure source, and the hydraulic pressure of the hydraulic fluid stored in the low pressure source is almost atmospheric pressure. Get smaller. However, it is not desirable to reduce the hydraulic pressure of the brake cylinder unnecessarily or to suppress the increase of the brake cylinder. For example, when the traveling speed of the vehicle is equal to or higher than the set speed and is being decelerated with a large deceleration, reducing the hydraulic pressure of the brake cylinder or suppressing the increase thereof (hereinafter, abbreviated as depressurizing or the like). ) Is not valid. On the other hand, when the traveling speed of the vehicle is lower than the set speed, it is often possible to reduce the pressure. The set speed can be set to a magnitude at which the vehicle can be considered to be in a stopped state, for example.

Further, it is desirable that the hydraulic pressure of the brake cylinder be reduced only when it is really necessary. For example, when the hydraulic pressure of the brake cylinder is actually equal to or higher than the set hydraulic pressure and the differential pressure before and after the pressure reducing control valve is equal to or higher than the set value, the control by the auxiliary control unit may be performed. When the hydraulic pressure is less than the set hydraulic pressure, the flow rate of the hydraulic fluid flowing through the pressure reducing control valve does not increase so much, and therefore the need to reduce the hydraulic pressure in the brake cylinder is low. Also, the hydraulic pressure of the brake cylinder is likely to be increased above the set hydraulic pressure,
If there is a high possibility that the differential pressure becomes equal to or higher than the set pressure, the increase in hydraulic pressure in the brake cylinder may be suppressed.
When the main control unit controls the hydraulic pressure of the brake cylinder to a magnitude according to the operating state of the brake operating member, the auxiliary control is performed when the operating state amount indicating the operating state of the brake operating member is equal to or greater than the set state amount. Control can be provided. The operation state quantity representing the operation state of the brake operation member is detected by the operation state quantity detection device. The operation state quantity of the brake operation member corresponds to the operation force, operation stroke, etc. of the brake operation member, but may be a physical quantity equivalent to the brake operation state quantity. For example, the hydraulic pressure of the master cylinder and the hydraulic pressure of the fluid passage connected to the master cylinder and the brake cylinder correspond to the physical quantity equivalent to the brake operation state quantity.

(18) The auxiliary control section includes a brake fluid pressure suppression section that suppresses an increase in the hydraulic pressure of the brake cylinder above a set pressure, according to any one of (1) to (17). Brake fluid pressure control device. In the brake fluid pressure control device described in this section, the hydraulic pressure of the brake cylinder is set so as not to exceed the set pressure when the traveling speed of the vehicle becomes the set speed or less. Increase is suppressed. When the traveling speed of the vehicle is equal to or lower than the set speed, it is possible to prevent the hydraulic pressure in the brake cylinder from becoming excessive. (19) A first control unit in which the auxiliary control unit makes the hydraulic pressure of the brake cylinder smaller than (a) a magnitude corresponding to an operation state amount representing an operation state of the brake operation member,
(b) Up to a second control unit that suppresses an increase in the hydraulic pressure of the brake cylinder at the time when the traveling speed of the vehicle becomes equal to or lower than the set speed, and (c) It is estimated that the vehicle can be stopped. The brake fluid pressure control device according to any one of items (1) to (18), including at least one of a third control unit that reduces the size. According to the first control section (a), the hydraulic pressure in the brake cylinder is made lower than the hydraulic pressure corresponding to the brake operation state amount. For example, it is possible to prevent the hydraulic pressure in the brake cylinder from increasing with the increase in the brake operation state amount. According to the second control unit of (b), the hydraulic pressure of the brake cylinder is held at the hydraulic pressure when the traveling speed becomes equal to or lower than the set speed, or is made smaller than the hydraulic pressure.
If the hydraulic pressure in the brake cylinder is maintained at the level when the traveling speed of the vehicle reaches the set speed, the vehicle can normally be kept in a stopped state. The need to be larger than that is low. According to the third control unit of (c), for example, the hydraulic pressure of the brake cylinder is reduced to a hydraulic pressure sufficient to maintain the stopped state when the vehicle is in a standard environment. (20) The auxiliary control unit includes a vehicle speed detection device that detects a traveling speed of the vehicle, and the hydraulic pressure of the brake cylinder is so set that the vehicle speed detected by the vehicle speed detection device is maintained below a set speed. The brake fluid pressure control device according to any one of items (1) to (19) for controlling the brake fluid pressure. For example,
The hydraulic pressure in the brake cylinder is reduced until the traveling speed of the vehicle becomes equal to or higher than the set speed, and then increased until it becomes equal to or lower than the set speed. In this way, the minimum value of the hydraulic pressure in the brake cylinder required to actually keep the vehicle in a stopped state can be known. If the brake cylinder hydraulic pressure is reduced to the minimum value required to actually keep the vehicle stopped, the flow rate of the hydraulic fluid flowing through the pressure reducing control valve can be minimized when the vehicle starts.

(21) The auxiliary control section includes a multi-step control section for controlling the brake cylinder hydraulic pressure in a plurality of steps while the vehicle traveling speed is equal to or lower than a set speed. (1) to (2)
The brake fluid pressure control device according to any one of items 0). For example, after the traveling speed of the vehicle becomes less than or equal to the set speed, the first
Different control is performed until the set time elapses and after the first set time elapses, or when the vehicle traveling speed is equal to or lower than the set speed and continues for the second set time or more, and Different control may be performed depending on whether the control is continued for a set time or longer. In particular,
The first half is controlled by the (a) first control section or (b) second control section in the first half, and the second half is controlled by the (19) (c) third control section or (20). It can be controlled by the department.

(22) When the operation of the brake operating member is loosened and the hydraulic pressure of the brake cylinder becomes larger than the operation state amount representing the operating state of the brake operating member, the auxiliary control section releases the auxiliary operation. The brake fluid pressure control device according to any one of (1) to (21), which terminates the control. (23) The main control unit starts control according to the operating state of the brake operating member of the hydraulic pressure of the brake cylinder from the time when the control by the auxiliary control unit ends (1) to (22) The brake fluid pressure control device according to claim 1. In the brake fluid pressure control device described in this section, the control of the auxiliary control unit is shifted to the control of the main control unit.
In other words, the auxiliary control end condition and the main control start state are satisfied at the same or almost the same time, and the control by the main control unit is performed subsequently to the control by the auxiliary control unit. In this case, since the differential pressure before and after the pressure reducing control valve is also small, it is possible to prevent the flow rate of the hydraulic fluid flowing through the pressure reducing control valve from becoming excessive even if the pressure reducing control valve is switched to the open state. You can

(24) The brake according to any one of (1) to (23), wherein the auxiliary control section includes an equalization control section that similarly controls the hydraulic pressures of the brake cylinders of the front, rear, left and right wheels. Hydraulic control device. For example, when a pressure increase control valve and a pressure reduction control valve are provided corresponding to each brake cylinder, these pressure increase control valve and pressure reduction control valve are similarly controlled for all brake cylinders. The hydraulic pressure in the brake cylinder is almost the same.

(25) By controlling the pressure increase control valve provided between the brake cylinder of the brake operated by hydraulic pressure and the high pressure source, and the pressure increase control valve, the hydraulic pressure of the brake cylinder is controlled. A main control unit that increases the pressure in response to a brake operation by a driver, and a pre-supply unit that supplies hydraulic fluid to the brake cylinder when the possibility that the brake operation is performed is high even though the brake operation is not performed. A brake fluid pressure control device including a charge control unit. If the hydraulic fluid is supplied to the brake cylinder before the brake operation is performed by the precharge control unit, the flow rate of the hydraulic fluid flowing through the pressure increase control valve at the start of control by the main control unit, that is, the inrush flow rate of the pressure increase control valve. Is smaller, vibration can be suppressed. The precharge control unit can supply, for example, the amount of hydraulic fluid required to complete the fast fill. The brake fluid pressure control device described in this section,
The technical features of items (1) to (24) can be adopted. (26) A pressure increasing control valve provided between a brake cylinder and a high pressure source of a brake operated by hydraulic pressure, a pressure reducing control valve provided between the brake cylinder and a low pressure source, and the pressure increasing A main control unit that includes a control device that controls the hydraulic pressure of the brake cylinder by controlling at least one of a control valve and a pressure reducing control valve, the control device controlling the hydraulic pressure of the brake cylinder to a desired magnitude. And, before the control of at least one of the pressure increase control valve and the pressure reduction control valve by the main control unit is started, the hydraulic fluid flowing through at least one of them within a preset time from the start of control by the main control unit. Of the brake fluid pressure control device for controlling the state of the brake cylinder so that the amount of the brake fluid is smaller than that when the control is not performed. In the brake fluid pressure control device described in this section, within the set time from the start of control by the main control unit,
For example, the amount of hydraulic fluid flowing through the pressure increase control valve is reduced within a time period in which it is estimated that the first fill will be completed. Thereby, the vibration of the pressure increase control valve by the main controller can be suppressed. The brake fluid pressure control device according to this section can adopt the technical features of (1) to (25). (27) The brake suppresses the rotation of the wheel by pressing the friction engagement member against a brake rotating body that is rotated integrally with the wheel by hydraulic pressure of the brake cylinder, and the auxiliary control unit The brake fluid pressure control device according to item (26), including a pressure boosting / depressurizing control unit that boosts the hydraulic pressure of the brake cylinder to a predetermined set pressure and then reduces the hydraulic pressure to substantially atmospheric pressure. If the hydraulic pressure of the brake cylinder is increased to the set pressure by the auxiliary control unit, the relative position between the friction engagement member and the brake rotating body is brought close to the target relative position, and then the brake cylinder is set to the atmospheric pressure. Decompressed to. In the case where the retraction spring for separating the friction engagement member from the brake rotor is not provided and the piston seal having the retraction function is not disposed between the piston and the cylinder housing, the piston and the friction engagement member are naturally used. The mating member is maintained at the target relative position, but is not completely retracted even with the piston seal.
The piston is retracted as the elastic deformation of the piston seal is restored. However, just because the decompression control valve is decompressed does not mean that the hydraulic pressure in the brake cylinder immediately drops to atmospheric pressure, so the elastically deformed piston seal does not immediately recover, and the pressure booster increases. The piston is kept at a position closer to the target relative position than when the depressurization controller is not provided. The friction engagement member is normally only in contact with the piston and is not connected. Therefore, unless the retraction spring is provided, the friction engagement member is kept at the target relative position. Further, due to the vibration of the unsprung member (the member on the wheel side of the suspension) accompanying the traveling of the vehicle when the brake is not operated, the clearance between the friction engagement member and the brake rotor is larger than that when the brake is released. It may have become. Especially when the piston seal having the retraction function is not provided between the piston and the cylinder housing, the above-mentioned brake clearance is likely to increase, but even when it is provided, the above-mentioned brake clearance increases. May occur. If a piston seal is provided,
Although the increase in clearance is suppressed, it is still difficult to prevent it completely. By design, if the coefficient of friction between the piston seal and the piston is increased,
Although it is possible to satisfactorily prevent the increase in the clearance, on the other hand, there is a possibility that the drag torque of the brake becomes large after the hydraulic pressure of the brake cylinder is made particularly high due to sudden braking. When the hydraulic pressure in the brake cylinder is especially high, the amount of elastic deformation of the caliper and frictional engagement member increases, and the piston is moved forward by a distance larger than usual relative to the cylinder housing. The piston is further advanced with respect to the piston seal, and slippage occurs between the piston and the piston seal. Therefore, even if the elastic deformation of the piston seal is completely restored as the hydraulic pressure of the brake cylinder is reduced later, the piston is not yet retracted sufficiently with respect to the cylinder housing, and the friction engagement member is applied to the brake rotating body. Keep pressed. Since this means an increase in the drag torque of the brake, it is not desirable to increase the friction coefficient between the piston seal and the piston too much, and even if a piston seal having a retraction function is provided, the vibration of the unsprung member will be It is difficult to completely prevent the increase of the brake clearance due to. From the above circumstances, even if the pressure reducing control valve is controlled so as to reduce the hydraulic pressure of the brake cylinder to the atmospheric pressure after the friction engagement member is once brought close to the rotating body of the brake, the brake clearance is still larger than that before the approach. It usually does not return. Therefore, the amount of hydraulic fluid consumed in the brake cylinder can be reduced and the amount of hydraulic fluid flowing through the pressure increase control valve can be reduced at the beginning of the brake operation by the main control unit later.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A brake fluid pressure device including a brake fluid pressure control device according to an embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the brake device includes a brake pedal 10 as a brake operating member, a pump device 12 as a dynamic hydraulic pressure source,
Master cylinder 14 as an operation type hydraulic pressure source, left and right front wheels 1
Brakes 20 and 21 including brake cylinders 18 and 19 provided at 6 and 17, and brakes 28 and 2 including brake cylinders 26 and 27 provided at the left and right rear wheels 24 and 25, respectively.
Including 9 etc. In the present embodiment, as shown in FIG. 2, the brakes 20, 21, 28, 29 are provided with a pair of brake pads 32a, 32b as friction engagement members by the hydraulic pressure of the brake cylinders 18, 19, 26, 27 on the wheels. 1
6, 17, 24, 25 is a hydraulic disc brake that suppresses the rotation of the wheels 16, 17, 24, 25 by being pressed against a rotating disc 33 that is rotatably mounted integrally with the rotating disc 33. is there. Since the disc brakes 20, 21, 28, and 29 have the same structure, the disc brake 20 will be representatively described.

The disc brake 20 has a pair of friction brake pads 32a, 32b which are held by a brake cylinder 18, a caliper 34 for holding the brake cylinder 18, and a mounting bracket 35 as a vehicle body side member so as to be axially movable. And the brake pads 32a,
32b, respectively. In this embodiment, it is a caliper floating type. Brake cylinder 1
In 8, the piston 37 is fitted in the cylinder housing so as to be liquid-tight and slidable. The cylinder housing is provided with a piston seal 38, and the space between them is kept liquid-tight. The piston seal 38 has a retract function. When high-pressure hydraulic fluid is supplied to the hydraulic chamber 36 of the brake cylinder 18, the piston 37 is advanced and the brake pad 32a is pressed against the rotary disc 33. The caliper 34 is moved in the axial direction, and the other brake pad 32b is pressed against the rotating disc 33. At that time, the brake pads 32a and 32b are compressed, the caliper 34 is elastically deformed, and the piston seal 38 is elastically deformed.

The pump device 12 includes a pump 40, a pump motor 42 that drives the pump 40, and an accumulator 44. The pump 40 pressurizes and discharges the hydraulic fluid in the reservoir 46, and the high-pressure hydraulic fluid discharged from the pump 40 is stored in the accumulator 44.
The hydraulic pressure of the accumulator 44 is the accumulator pressure sensor 4
8, the pump motor 42 is controlled so that the hydraulic pressure detected by the accumulator pressure sensor 48 is maintained within a predetermined set range. A check valve 49 is provided on the discharge pressure side of the pump 40 to prevent the hydraulic fluid from flowing back to the pump 40. A relief valve 50 is provided between the high pressure side and the low pressure side of the pump 40 to prevent the pump pressure from becoming excessive. In addition, pump 4
0 may be a plunger pump or a gear pump. Further, a pressure switch may be used instead of the accumulator pressure sensor 48.

The master cylinder 14 is of a tandem type including two pressurizing pistons 51 and 52, and the front of the pressurizing pistons 51 and 52 are pressurizing chambers 53 and 54, respectively. Between the pressure piston 52 and the bottom of the housing, 2
Return springs 55 and 56 are provided between the two pressurizing pistons 51 and 52, respectively. Brake pedal 1
When 0 is depressed, hydraulic pressures of the same height are generated in the two pressurizing chambers 53 and 54. A brake passage 18 of the left front wheel 16 is connected to one pressurizing chamber 53 by a liquid passage 58, and a brake cylinder 26 of the left rear wheel 24 is connected to the other pressurizing chamber 54 by a liquid passage 59. In the middle of these liquid passages 58 and 59, the master shutoff valve 6 is provided.
0, 62 are provided. The master shutoff valves 60, 62 are normally open valves that are open when no current is supplied to the solenoid. Further, the brake cylinders 18 and 19 of the left and right front wheels 16 and 17 are connected by the liquid passage 64, and the brake cylinders 26 and 27 of the left and right rear wheels 24 and 25 are connected to the liquid passage 65.
Connected by. Communication control valves 67 and 68 are provided in the liquid passages 64 and 65, respectively. The communication control valves 67 and 68 are normally open valves that are open when no current is supplied to the solenoids.

In this embodiment, the master cylinder 1
The brake cylinders 18 of the left front wheel 16 and the brake cylinders 26 of the left rear wheel 24 are connected to the pressurizing chambers 53 and 54 of No. 4, respectively, and the two brake cylinders on the front wheel side and the brake cylinders on the rear wheel side are respectively connected. It is connected. Further, the master shutoff valves 60 and 62, the communication control valve 6
Since all of the valves 7, 68 are normally open valves, the hydraulic pressure of the master cylinder 14 can be supplied to all the brake cylinders 18, 19, 26, 27 even when the current is not supplied, and the brakes 20, 21, 28, 29 can be activated.

A simulation device 76 is provided in a portion of the liquid passage 59 upstream of the master shutoff valve 62. The simulation device 76 includes a stroke simulator 77 and a simulator control valve 78, and the stroke simulator 77 is connected to the liquid passage 59 via the simulator control valve 78. The simulator control valve 78 is a normally closed valve that is closed when no current is supplied to the solenoid.

The pump device 12 is connected to all the brake cylinders 18, 19, 26, 27 via a liquid passage 92. In addition, the brake cylinders 18, 19, 2
6, 27 are respectively provided with linear valve devices 100, 102, 104, 10 as individual hydraulic pressure control valve devices.
6 is provided. The linear valve devices 100 to 106 are
Each includes a pressure increasing linear valve 110 and a pressure reducing linear valve 112 which are normally closed valves. Boosting linear valve 11
0 is provided in the above-mentioned liquid passage 92, and the pressure reducing linear valve 1
12 is provided in a liquid passage 118 connecting the brake cylinders 18, 19, 26, 27 and the reservoir 46.

The pressure-increasing linear valve 110 and the pressure-decreasing linear valve 112, which are normally closed valves, as shown in FIG.
0, and a seating valve 134 including a valve element 132 that can be moved toward and away from the valve seat 130.
In the seating valve 134, the spring 136 urges the valve element 132 in a direction to seat it on the valve seat 130.
It also includes a solenoid 139 with a coil 138,
When current is supplied to the coil 138, the movable member 139a
Is applied to the fixing member 139b, that is, in the direction of separating the valve element 132 from the valve seat 130. On the other hand, the differential pressure acting force corresponding to the differential pressure between the front and the rear acts on the valve element 132 in the direction of separating it from the valve seat 130.
Therefore, the biasing force of the spring 136, the differential pressure acting force, and the electromagnetic driving force act on the linear valve, and the relative relationship between these forces determines the relative relationship of the valve element 132 with respect to the valve seat 130. By controlling, the differential pressure between the front and back can be controlled.

The pressure-increasing linear valve 110 includes a pump device 12 and brake cylinders 18, 19, 26, 2 respectively.
The differential pressure between the front and the rear corresponds to the differential pressure between the output hydraulic pressure of the pump device 12 and the hydraulic pressure of the brake cylinder. The pressure-reducing linear valve 112 is provided between the brake cylinders 18, 19, 26, 27 and the reservoir 46, and since the hydraulic pressure of the reservoir 46 is atmospheric pressure, the differential pressure across the brake cylinders 18, 19, 26, The size corresponds to the liquid pressure of 27.

In the present embodiment, the brake cylinder 18, is controlled by the control of the linear valve devices 100 to 106.
The hydraulic pressures of 19, 26 and 27 can be individually controlled by utilizing the hydraulic fluid of the pump device 12. Linear valve device 1
A brake control actuator is constituted by 00 to 106 and the like.

Further, the pressure increasing linear valve 11 in the liquid passage 92 is provided.
A hydraulic sensor 158 is provided between 0 and the pump device 12. The hydraulic pressure sensor 158 detects the hydraulic pressure of the hydraulic fluid on the high pressure side of the pressure-increasing linear valve 110. A hydraulic pressure sensor 158 is used as the hydraulic pressure on the high pressure side of the pressure increasing linear valve 110.
If the detection value of the accumulator pressure sensor 48 is adopted, the influence of the pressure loss between the pump device 12 and the pressure-increasing linear valve 110 can be reduced. Valve device 100-
The control accuracy of 106 can be improved. If the hydraulic pressure value by the hydraulic pressure sensor 158 is substantially constant, the differential pressure across the pressure-increasing linear valve 110 will be determined according to the hydraulic pressure in the brake cylinder.

The brake control actuator is the brake E.
It is controlled based on a command from the CU 160. Brake EC
U160 is, as shown in FIG.
The main component is a computer having 164, a RAM 166, an input / output unit 168, and the like. The input / output unit 168 includes the accumulator pressure sensor 48 and the hydraulic pressure sensor 1 described above.
In addition to 58, master pressure sensors 170 and 172 that detect the hydraulic pressures in the fluid passages 58 and 59, and brake hydraulic pressure sensors 174, 175, 176 that detect the hydraulic pressures in the brake cylinders 18, 19, 26, and 27, respectively. 177, wheel speed sensors 179, 180, 181, 182 for detecting the wheel speeds of the wheels 16, 17, 24, 25 respectively, a stroke sensor 190 for detecting the operation stroke of the brake pedal 10, and an operation state of an accelerator pedal (not shown). The throttle switch 192 for detection and the like are connected. In the present embodiment, whether the accelerator pedal is in the operated state or the non-operated state is detected based on the state of the throttle switch that detects opening / closing of the throttle valve. Further, the output signals of the wheel speed sensors 179 to 182 are used at the time of antilock control and traction control, but the traveling speed of the vehicle can be estimated based on the wheel speeds of a plurality of wheels. In this embodiment, the vehicle speed is estimated based on the wheel speeds of the four wheels, but a separate vehicle speed sensor may be provided. Also,
Pump motor 42, each linear valve device 100 to 10
6, simulator control valve 78, each master shutoff valve 60, 6
2. The solenoids of the communication control valves 67 and 68 are connected via the drive circuit 196, respectively.

In this hydraulic brake device, when the brake pedal 10 is operated while the vehicle is traveling, the output signal from the stroke sensor 190 and the master pressure sensor 17 are output.
The required braking force required by the driver is obtained based on the output signals of 0 and 172, and the target hydraulic pressure of each brake cylinder is obtained based on the required braking force. Then, each of the linear valve devices 100 to 106 is realized so that the target hydraulic pressure can be realized.
Is controlled. With the master shutoff valves 60, 62 closed and the brake cylinders 18, 19, 26, 27 shut off from the master cylinder 14, the hydraulic pressure of the pump device 12 controls the linear valve devices 100 to 106 separately. Controlled by. In the present embodiment, the required braking force is determined based on the stroke and the master pressure, but it may be determined based on the stroke or the master pressure. You can do so. Further, an operating force sensor may be provided so that the determination can be made based on the output signal from the operating force sensor. In any case, it can be determined based on the operation state amount representing the operation state of the brake operation member. The operation state quantity of the brake operation member may be directly detected, or may be detected based on a physical quantity equivalent thereto.

In the pressure-increasing linear valve 110 and the pressure-decreasing linear valve 112, as shown in FIG. 5, the valve opening pressure decreases as the supply current increases (the electromagnetic driving force increases). In other words, when the differential pressure between the front and the back is small, a large current is required to bring it into the open state. Further, in the control, when the differential pressure before and after the linear valve is reduced, the supply current is increased as the differential pressure is reduced, and when the differential pressure before and after the linear valve is increased, the supply current is reduced. To be made. In principle, the pressure-increasing linear valve 110 is supplied with a current including a valve-opening current according to the differential pressure before and after that time point and a current according to the increase amount of the required braking force. When a pressure increase request is made, the supply current to the pressure reducing linear valve 112 remains 0 (closed state), and the supply current to the pressure increasing linear valve 110 is controlled. When the pressure-increasing linear valve 110 is opened, the hydraulic pressure of the pump device 12 becomes equal to the brake cylinders 18, 19, 26, 27 (hereinafter, the brake cylinder 18 will be representatively described. The same applies to other brake cylinders. The brake cylinder hydraulic pressure is increased. The pressure difference between the hydraulic pressure of the pump device 12 and the hydraulic pressure of the brake cylinder 18 is determined by the pressure-increasing linear valve 110.
The larger the current supplied to the cylinder, the smaller it becomes, and the brake cylinder hydraulic pressure is increased.

The same applies to the pressure-reducing linear valve 112, and a current including a valve-opening current according to the differential pressure before and after that time and a current according to the amount of decrease in the required braking force is supplied. When a pressure reduction request is made, the current supplied to the pressure-increasing linear valve 110 remains 0 (closed), and the current supplied to the pressure-decreasing linear valve 112 is controlled. Pressure reducing linear valve 1
When the brake cylinder 1 is opened, the brake cylinder 1
The hydraulic fluid of No. 8 flows out to the reservoir 46, and the brake cylinder fluid pressure is reduced.

During operation of the brake pedal 10,
The pressure-increasing and pressure-decreasing linear valves 110 and 112 are controlled according to the execution of the main control program represented by the flowchart of FIG. In step 1 (hereinafter, abbreviated as S1; the same applies to other steps), it is detected whether or not stop control, which will be described later, is being performed. When the stop-time control flag is in the set state, S2 and thereafter are not executed. When the stop control is not being performed, it is detected in S2 whether or not the brake operation is being performed based on the state of the brake switch 190. When the brake is being operated, the required braking force is obtained based on the stroke and the master pressure in S3 to S5, and the target hydraulic pressure of each brake cylinder 18 is obtained. In steps S6 and S7, it is determined whether the pressure increase request, the pressure decrease request, or the hold request is made based on the deviation between the target hydraulic pressure in each brake cylinder 18 and the actual hydraulic pressure in the brake cylinder 18. For example, if the deviation, which is the value obtained by subtracting the actual brake cylinder hydraulic pressure from the target hydraulic pressure, is larger than the positive set pressure, the pressure increase request is made, and if the deviation is smaller than the negative set pressure, the pressure decrease request is made. In other cases, the request is a holding request.

If it is a pressure increase request, in S8,
The pressure increasing linear valve 110 is controlled while the pressure reducing linear valve 112 is kept closed. In the case of the pressure reduction request, the pressure reduction linear valve 112 is controlled in S9 while the pressure increase linear valve 110 is closed. If it is a holding request, in S10, the supply currents to the pressure-increasing linear valve 110 and the pressure-decreasing linear valve 112 are both set to 0 so that the valve is closed. in this way,
In the present embodiment, during normal brake operation, the hydraulic pressure of the brake cylinder is controlled by the control of the linear valve device so that the braking force required by the driver is satisfied, but this control is controlled by the main control unit. (Hereinafter, abbreviated as main control) is one mode. In the present embodiment, control by the auxiliary control unit is performed in addition to this main control. The control by the auxiliary controller includes precharge control and stop control. The precharge control is a control that is performed before the opening control of the pressure-increasing linear valve 110 by the main control unit is started. This is a control for reducing the amount of inflowing hydraulic fluid at the beginning.
The stop control is performed by the pressure reducing linear valve 112 by the main control unit.
The control is performed before the start of the valve opening control of 1. and is a control for reducing the flow rate of the hydraulic fluid flowing at the start of the main control of the pressure reducing linear valve 112. The precharge control and the stop control will be described below.

Precharge control is performed by the brake pad 32.
This is a control of the state of the brake cylinder that is performed so that the relative positions of a and b with respect to the rotor 33 are kept in close positions without abutting. In the non-operating state of the brake, the hydraulic pressure in the brake cylinder 18 is almost atmospheric pressure.
When a brake operation request is made, hydraulic fluid is supplied from the pump device 12 to the brake cylinder via the pressure-increasing linear valve 110. In this case, pressure boosting linear valve 1
The differential pressure before and after 10 is large, the flow rate of the hydraulic fluid flowing through the pressure-increasing linear valve 110 is large, and vibration occurs. It is known from experiments and the like that when the hydraulic pressure in the brake cylinder 18 is about 0 to 2 MPa and the pressure increase gradient is 20 MPa / sec or more, the pressure increase linear valve 110 vibrates. Further, when the brake is not operated, the brake pads 32a and 32b are separated from the rotor 33. During vehicle travel, these clearances are usually larger than when the brake is released due to vibration of the unsprung member. Further, it is known that the relationship shown in FIG. 9 is established between the hydraulic fluid amount and the hydraulic pressure of the brake cylinder 18. Until the first fill at the beginning of the brake operation is completed, that is, before the brake pads 32a and 32b come into contact with the rotor 33, the amount of change in the hydraulic pressure with respect to the amount of change in the hydraulic fluid in the brake cylinder 18 changes. It becomes smaller and the consumption of hydraulic fluid becomes larger. A large amount of hydraulic fluid is required until the end of the first fill, and the amount of hydraulic fluid flowing through the pressure-increasing linear valve 110 increases. Therefore, at the beginning of the brake operation, the brake cylinder 1
The hydraulic fluid consumption in 8 is large, and the pressure boosting linear valve 1
The amount of hydraulic fluid flowing through 10 increases, causing vibration.

Based on the above circumstances, if the hydraulic pressure of the brake cylinder 18 is increased by the precharge control so that the brake pads 32a, 32b are brought close to the rotor 33, the main controller When the pressure-increasing linear valve 110 is controlled by, the flow rate of the hydraulic fluid flowing through the pressure-increasing linear valve 110 can be reduced, and the amount of hydraulic fluid flowing at the beginning of the operation can be reduced. Vibration of the linear valve 110 can be suppressed. In the present embodiment, the hydraulic pressure of the brake cylinder 18 is such that the first fill is almost completed and the drag does not occur (first set pressure: Pt1).
The pressure is increased up to and maintained until the main control is performed (until the brake pedal 10 is operated). The pre-charge control is started before the brake pedal 10 is operated, at the time when it is predicted that the brake pedal 10 is likely to be operated, that is, when the accelerator pedal is released.

The precharge program represented by the flowchart of FIG. 7 is repeatedly executed. S51, 52
At, it is determined whether the brake pedal 10 is in the non-operated state and the operation of the accelerator pedal is released. When neither the brake pedal 10 nor the accelerator pedal is operated, S53 and subsequent steps are executed. After S53, it is repeatedly executed from the release of the operation of the accelerator pedal to the operation of the brake pedal 10. In S53, it is determined whether the flag during the sample time is in the set state. If it is not in the set state, the set state flag is set in S54, and then the timer is started in S55. In S56, the brake cylinder 18
Is detected, and in S57, it is determined whether or not it is larger than the maximum value. If it is larger than the maximum value, S5
At 8, the brake cylinder hydraulic pressure is maximized. In S59, it is determined whether the sample time has elapsed. If it has not yet elapsed, the flag during the sample time remains unchanged. When this program is executed next, the determination in S53 is YES, and S56 and subsequent steps are executed. Thus, in S53 to 59, the maximum value of the hydraulic pressure of the brake cylinder 18 during the sample time is obtained. The hydraulic pressure of the brake cylinder can be acquired more accurately than the case where it is based on the detected one-time brake cylinder hydraulic pressure.

If the sample time has elapsed, S59
The result of the determination is YES, and in S60, it is determined whether or not the maximum value of the brake cylinder 18 during the sample time is higher than the above-mentioned first set pressure Pt1. When it is higher than the first set pressure Pt1, a pressure reduction request is output in S61, and when it is lower than the first set pressure Pt1, a pressure increase request is output in S62. After that, in S63, 64, and 65, the flag during the sample time is reset, the timer is reset, and the maximum value is reset to 0. When this program is first executed after the accelerator pedal is released, the hydraulic pressure in the brake cylinder 18 is normally 0, so the determination in S60 is Y.
It becomes ES, and a pressure increase request is output in S62.
After that, the hydraulic pressure of the brake cylinder 18 becomes the first set pressure Pt1.
When it exceeds, the pressure reduction request is output in S61, and the hydraulic pressure of the brake cylinder 18 is maintained at substantially the first set pressure Pt1 until the brake operation is started. If the brake pedal 10 is operated or the accelerator pedal is operated, S5
The determination of 1 is YES or the determination of S52 is NO. In this case, so-called precharge control is not performed. The precharge control is ended during the precharge control. If the precharge control is performed in this way, the flow rate of the hydraulic fluid in the pressure-increasing linear valve 110 at the start of control of the main controller can be reduced,
Since the amount of hydraulic fluid at the beginning of control can be reduced, vibration can be suppressed. Further, as shown in FIG. 10, the current supplied to the pressure-increasing linear valve 110 at the start of control by the main control unit can be reduced, and the braking delay can be reduced.

In the above embodiment, the hydraulic pressure of the brake cylinder 18 is kept substantially constant in the precharge control, but the hydraulic pressure of the brake cylinder 18 is once increased to the first set pressure. After the pressure is set, the pressure may be reduced. Even if the hydraulic pressure of the brake cylinder is reduced, compared to the case where the precharge control is not performed, the differential pressure before and after the pressure-increasing linear valve 110 becomes smaller and the clearance becomes smaller, so that the vibration can be suppressed. it can. The hydraulic pressure of the brake cylinder 18 may be reduced after a lapse of a set time after the hydraulic pressure of the brake cylinder 18 reaches the first set pressure Pt1, or the first set pressure P
The pressure may be reduced when it is estimated that the brake pedal 10 is unlikely to be operated in the near future after reaching t1.

The hydraulic pressure in the brake cylinder 18 may be reduced from the first set pressure Pt1 by a set pressure or may be reduced to atmospheric pressure. Vibration can be suppressed even if the hydraulic pressure of the brake cylinder 18 is reduced to atmospheric pressure. The hydraulic fluid may be supplied to the brake cylinder 18 at least once until the brake pedal 10 is operated, and the brake pads 32a and 32b may approach the rotor 33. Even if the hydraulic pressure of the brake cylinder 18 is reduced to the atmospheric pressure, the brake pads 32a and 32b are not completely retracted. The piston 37 is retracted as the elastic deformation of the piston seal 38 is restored. But,
The fact that the pressure-reducing linear valve 112 is opened does not mean that the hydraulic pressure in the brake cylinder immediately drops to atmospheric pressure. Therefore, the elastically deformed piston seal 38 does not immediately recover, and the piston 37 Is kept close to the target relative position. Since the brake pads 32a and 32b are only in contact with the piston 37 and are not connected to each other, the brake pads 32a and 32b are substantially maintained at the target relative positions. Further, due to the vibration of the unsprung member (the member on the wheel side of the suspension) accompanying the traveling of the vehicle in the non-operating state of the brake, the clearance between the brake pads 32a and 32b and the brake rotor 33 is released when the brake is released. It may be larger. According to the piston seal 38,
Although the increase in clearance is suppressed, it is still difficult to prevent it completely. By design, if the friction coefficient between the piston seal 38 and the piston 37 is increased,
Although it is possible to satisfactorily prevent the increase in the clearance, on the other hand, on the other hand, the brake cylinder 18 is subjected to sudden braking.
The drag torque of the brake may increase after the hydraulic pressure of is particularly increased. When the hydraulic pressure of the brake cylinder 18 is particularly high, the amount of elastic deformation of the caliper 34 and the brake pads 32a, 32b becomes large, and the piston 37 can be advanced by a distance larger than usual with respect to the cylinder housing. The piston 37 is further advanced with respect to the piston seal 38 elastically deformed to the limit, and a slip occurs between the piston 37 and the piston seal 38. Therefore, even if the elastic deformation of the piston seal 38 is completely restored as the hydraulic pressure of the brake cylinder 18 is reduced later, the piston 37 is not yet retracted sufficiently with respect to the cylinder housing, and the brake pads 32a, 32b are removed. It is kept pressed against the brake rotor 33. Since this means an increase in the drag torque of the brake, it is not desirable to increase the coefficient of friction between the piston seal 38 and the piston 37 so much that the piston seal 38 also reduces the brake clearance due to the vibration of the unsprung member. It is difficult to prevent the growth completely. From the above circumstances, once the brake pad 32
Even if the pressure reducing linear valve 112 is controlled so that the hydraulic pressure of the brake cylinder 18 is reduced to the atmospheric pressure after the a and b are brought close to the brake rotating body 33, the brake clearance does not return to the size before the approach. . Therefore, the amount of hydraulic fluid consumed in the brake cylinder 18 can be reduced and the amount of hydraulic fluid flowing through the pressure increase control valve can be reduced at the beginning of the brake operation by the main control unit later.

Further, the control for increasing and then decreasing the hydraulic pressure of the brake cylinder 18 is performed from the release of the operation of the accelerator pedal to the operation of the brake pedal 10.
It may be executed intermittently, for example, at set time intervals. The brake pedal 10 is not always immediately depressed just because the operation of the accelerator pedal is released. Therefore, if it is performed intermittently, the energy consumption can be reduced. In the above embodiment, the brake pads 32a,
Although the brake cylinder hydraulic pressure is held in a state where b is not in contact with the rotor 33 and is in close proximity, the brake cylinder hydraulic pressure is held in a state in which the brake pads 32a and 32b are in contact with the rotor 33. You may For example, in FIG. 9, the pressure may be increased to the first set pressure Pt1 '. In this case, the brake pads 32a,
Although b is in contact with the rotor 33, since the pressing force is small, the driver does not feel uncomfortable. Further, it is possible to reduce the pressure after increasing it to the first set pressure Pt1 '.

It is also possible to control the hydraulic pressure in the brake cylinder 18 without depending on the relative position of the pad in the disc brake with respect to the rotor.
For example, as shown in FIGS. 12A and 12B, the hydraulic pressure of the brake cylinder 18 is increased / decreased according to a predetermined pattern, for example. Further, the control according to the pattern and the control based on the relative position can be selectively performed, or the control in which these are combined can be performed. For example, the control based on the relative position may be performed for the first time, and the control according to the pattern may be performed when the brake operation is not performed even after a certain period of time.

Next, the vehicle stop control will be described.
In the present embodiment, when it is detected that the vehicle is stopped, the hydraulic pressure of the brake cylinder 18 is prevented from becoming excessive. When the operation of the brake pedal 10 is loosened when the vehicle starts, the hydraulic fluid is caused to flow from the brake cylinder 18 to the reservoir 46 by the opening control of the pressure reducing linear valve 112 by the main controller.
In this case, if the differential pressure across the pressure reducing linear valve 112 is large, the flow rate of the hydraulic fluid flowing through the pressure reducing linear valve 112 increases, and the vibration of the pressure reducing linear valve 112 increases. On the other hand, if the hydraulic pressure in the brake cylinder 18 is suppressed from becoming excessive, the pressure reducing linear valve 11 is controlled during the opening control of the pressure reducing linear valve 112 by the main controller.
It is possible to reduce the flow rate of the hydraulic fluid flowing through the valve 2, and to suppress the vibration of the pressure reducing linear valve 112. It is possible to reduce the frequency with which the flow rate of the hydraulic fluid flowing through the pressure reducing linear valve 112 increases.

It is not desirable to reduce the hydraulic pressure of the brake cylinder 18 indiscriminately or to suppress its increase. On the other hand, when the traveling speed of the vehicle is less than the set speed,
When it can be considered that the brake cylinder is almost stopped, the hydraulic pressure of the brake cylinder may be reduced or the increase may be suppressed. On the other hand, when the differential pressure before and after the decompression linear valve 112 does not become so large, it is not necessary to reduce the hydraulic pressure of the brake cylinder 18. During normal brake operation, the hydraulic pressure of the brake cylinder 18 is controlled by the main control unit to a magnitude according to the master pressure and stroke, so during deceleration of the vehicle, the hydraulic pressure of the master cylinder 14 and the brake cylinder 18 are reduced. Almost corresponds to hydraulic pressure. Therefore, when the hydraulic pressure in the master cylinder 14 is high, the hydraulic pressure in the brake cylinder 18 is also high. Therefore,
In the present embodiment, when the hydraulic pressure in the master cylinder 14 is equal to or higher than the set pressure and the traveling speed of the vehicle becomes lower than the set speed, the hydraulic pressure in the brake cylinder 18 increases above the second set pressure Pt2. Is suppressed. Depending on the situation, the second set pressure Pt2 may be maintained or the second set pressure Pt2 may be held.
It is decompressed to. In any case, the increase according to the master cylinder pressure (the increase according to the increase in the brake operating force) is suppressed. For example, the second set pressure Pt2 can be made large enough to keep the vehicle stationary. For example, it can be obtained in advance assuming a state where the vehicle is stopped on a substantially horizontal road surface, but it can also be determined each time depending on the state in that case. For example, it can be determined by the inclination angle of the vehicle, the road surface μ, the installation load, and the like.

Next, when the set time has elapsed after the traveling speed of the vehicle has become less than or equal to the set speed, the hydraulic pressure in the brake cylinder 18 is controlled to a magnitude at which the vehicle does not actually move. Since the above-mentioned second set pressure Pt2 is set to a value that can hold the vehicle in a stopped state, it may be different from the value required to actually hold the vehicle in a stopped state. Since the second set pressure Pt2 is set to a large value, the hydraulic pressure in the brake cylinder 18 is usually reduced in this case. In the present embodiment, the hydraulic pressure of the brake cylinder 18 is reduced / increased so that the vehicle speed does not exceed the set speed, and the minimum value of the brake cylinder 18 for keeping the vehicle speed smaller than the set speed is obtained. If the vehicle speed is equal to or higher than the set speed, increase the hydraulic pressure in the brake cylinder 18,
When the vehicle speed is lower than the set speed, the hydraulic pressure in the brake cylinder 18 is reduced. By doing so, the minimum brake cylinder hydraulic pressure for actually maintaining the vehicle in a stopped state is obtained, and is maintained at that level.
As described above, in the present embodiment, the hydraulic pressure of the brake cylinder 18 is controlled in two stages when the vehicle is stopped. The hydraulic pressure in the brake cylinder 18 is controlled to a magnitude sufficient to ensure that the vehicle is stopped, and then to the minimum required to keep the vehicle stopped.

When the operation of the brake pedal 10 is released, the hydraulic pressure in the master cylinder 14 decreases. When the hydraulic pressure in the master cylinder 14 becomes equal to or lower than the hydraulic pressure in the brake cylinder 18, the control by the main controller is started. The decompression linear valve 112 is controlled according to the brake operation state, and the hydraulic fluid is decompressed from the brake cylinder 18 in response to the release of the operation of the brake pedal 10.
Is drained through. In this case, the differential pressure before and after the pressure-reducing linear valve 112 is sufficiently small,
The flow rate of the hydraulic fluid flowing through the pressure-reducing linear valve 112 is reduced, and the vibration of the pressure-reducing linear valve 112 can be suppressed. It is known from experiments and the like that when the hydraulic pressure in the brake cylinder 18 is 10 MPa or more, vibration occurs when the pressure reducing gradient is 10 MPa / sec or more, and this is also taken into consideration when determining the second set pressure. To be done.

In S100 to 103, whether the vehicle speed is less than or equal to the set speed (a size that can be considered to be almost stopped), whether the master cylinder pressure is greater than or equal to the set pressure, and the increase amount of the master cylinder pressure is set. It is detected whether the amount of increase is less than or equal to the increase amount, and whether the hydraulic pressure of the master cylinder 14 is less than the hydraulic pressure of the brake cylinder 18. When the traveling speed of the vehicle is equal to or lower than the set speed and the hydraulic pressure in the master cylinder 14 is equal to or higher than the set pressure, the brake cylinder 18
If the amount of increase in the hydraulic pressure of the master cylinder 14 is equal to or less than the set amount of increase,
The control flag during stop is set. In S105, it is determined whether or not the first holding end flag is in the set state, and if it is not in the set state, in S106, the target hydraulic pressure of the brake cylinder 18 is the second set pressure Pt2.
The hydraulic pressure of the brake cylinder 18 is controlled to be (stopped holding hydraulic pressure) so as to be maintained at the second set pressure Pt2. First
When the holding end flag is in the reset state, control is performed to keep the hydraulic pressure of the brake cylinder 18 at the second set pressure Pt2. When the control for maintaining the second set pressure Pt2 is continued for the set time or longer, the determination in S107 is YES, and the first holding end flag is set in S108.

When the first holding end flag is set, the hydraulic pressure in the brake cylinder 18 is controlled to a value at which the vehicle does not actually move. In S109, it is determined whether the vehicle speed is equal to or higher than the set speed. If the speed is equal to or higher than the set speed, a pressure increase request is output in S110. If the speed is lower than the set speed, it is determined in S111 whether or not the pressure increase linear valve 110 was controlled last time. , S112, the pressure reduction request is output. In this way, by increasing or decreasing the hydraulic pressure of the brake cylinder, the minimum required hydraulic pressure of the brake cylinder 18 for actually keeping the vehicle in a stopped state is obtained. In this case, the first holding end flag is in the set state, but the second holding flag is in the reset state, so the determination in S105 is YES. S113
The determination in step NO is NO and step S109 is executed.
When the vehicle speed is equal to or lower than the set speed and the previous pressure increase request is output, the second holding flag is set in S113, and the hydraulic pressure of the brake cylinder 18 at that time is the target in S114 and 115. The hydraulic pressure is used and the holding control is performed. At that point, the hydraulic pressure in the brake cylinder is controlled to the minimum amount that can actually keep the vehicle stationary. After that, in S117 to 119,
It is detected whether the traveling speed of the vehicle is equal to or lower than the set speed, and if the set speed is exceeded, the pressure is increased. The hydraulic pressure of the brake cylinder 18 is controlled so that the vehicle does not move. When it is executed next time, since both the first holding end flag and the second holding flag are in the set state, S10 is executed.
The determinations of 5 and 113 are both YES, and S116 and subsequent steps are controlled.

On the other hand, when the operation of the brake pedal 10 is loosened, the hydraulic pressure of the brake cylinder 18 is controlled by the main controller. The determination in S103 is YES
Then, in S120 to 122, the stop control flag is reset, the first holding end flag is reset, and the second holding flag is reset. If the stop control flag is reset, S1 of the main control program described above
The result of the determination is NO, and S2 and subsequent steps of the main control program are executed. The hydraulic pressure of the brake cylinder 18 is controlled by the main control unit, and the target hydraulic pressure is determined to be the magnitude determined based on the stroke of the brake pedal 10 and the master pressure. The hydraulic pressure of the brake cylinder 18 is reduced by the control of the pressure reducing linear valve 12. In this case, since the differential pressure across the pressure reducing linear valve 112 is not so large, the flow rate of the hydraulic fluid flowing through the pressure reducing linear valve 112 can be suppressed. Also, when the increase amount of the hydraulic pressure of the master cylinder 14 is equal to or larger than the set increase amount, the stop time control flag and the like are similarly reset.
This is because when the driver depresses the brake pedal 10 during the stop, that is, when the brake pedal 10 is further pressed during the stop, the driver wants to increase the hydraulic pressure of the brake cylinder 18.

As described above, in this embodiment, as shown in FIG.
The hydraulic pressure in the brake cylinder 18 is reduced to the second set pressure Pt2 at time t1 in 1 and further reduced at time t2. Then, the minimum brake cylinder hydraulic pressure that can prevent the movement of the vehicle is obtained, and the time t
After 3, the hydraulic pressure in the brake cylinder 18 is controlled to its minimum value. Further, the operation of the brake pedal 10 is released, and at time t4 when the master cylinder pressure becomes lower than the brake cylinder pressure, the control is switched to the control by the main control unit. Further, when the traveling speed of the vehicle becomes equal to or lower than the set speed, if the hydraulic pressure in the brake cylinder is the second set pressure Pt2, the hydraulic pressure is maintained at that level, and the brake operating force is further increased. However, the hydraulic pressure in the brake cylinder does not increase with the increase in the brake operating force.

In the above-described embodiment, the minimum value of the hydraulic pressure of the brake cylinder 18 required to keep the vehicle in a stopped state is obtained while detecting the actual vehicle speed. While the vehicle is stopped, the vehicle speed may be constantly detected, and the vehicle speed may be reduced and increased repeatedly. It is also possible to maintain the hydraulic pressure when the traveling speed of the vehicle becomes equal to or lower than the set speed.

As described above, in the present embodiment, the main control unit is configured by the portion of the brake ECU 160 that stores the main control program of FIG. An auxiliary control unit is configured by a part that stores a program, a part that executes the program, and the like. Of the auxiliary control unit, the portion that stores S60 to 62, the portion that executes S60, and the like constitute a friction engagement member approaching portion. The frictional engagement member approaching section is also a hydraulic pressure control section corresponding to the approaching position. Further, of the auxiliary control unit, the brake operation prediction time control start unit is configured by a part or the like which is executed after S53 when the determination in S52 is YES. Furthermore, among the auxiliary control units, S1
If the determination of 00 is YES, the vehicle stop control start unit is configured by the part or the like that executes S101 and the subsequent steps. A brake fluid pressure suppression unit is configured by S106 and the like.

In the above embodiment, the case where the hydraulic pressure of the brake cylinder 18 is controlled by the main controller to a magnitude according to the brake operation state has been described, but the present invention is not limited to this. When the traction control and the vehicle stability control are performed by the main control unit, the precharge control can be performed before the valve opening control of the pressure boosting linear valve 110. For example, when the main control unit starts the traction control and the vehicle stability control when the predetermined start condition is satisfied, the precharge control is performed when the condition on the stable side of the start condition is satisfied. Let it start. Further, it is not impossible to apply the method when the pressure increasing control is changed to the pressure reducing control or the pressure reducing control is changed to the pressure increasing control during the control such as the anti-lock control, the traction control and the vehicle stability control. further,
It is not essential to perform both the precharge control and the stop time control, and the effect of the present invention can be enjoyed even when only one of them is performed. Further, the output hydraulic pressure of the pump device may be reduced before the pressure-increasing linear valve is opened.
If the output hydraulic pressure of the pump device is suppressed, the differential pressure before and after the pressure-increasing linear valve can be reduced. This is effective when the present invention is applied during the operation of the brake, not before the operation of the brake.

Further, the structure of the brake device is not limited.
The pressure-increasing linear valve and the pressure-decreasing linear valve can be appropriately opened and closed normally. The brake can also be a drum brake. The present invention, in addition to the embodiments described in the above [problems to be solved by the invention, problem solving means and effects], various modifications based on the knowledge of those skilled in the art,
It can be carried out in an improved manner.

[Brief description of drawings]

FIG. 1 is a brake device including a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a disc brake of the brake device.

FIG. 3 is a diagram conceptually showing a linear valve device of the brake fluid pressure control device.

FIG. 4 is a diagram showing the vicinity of a brake ECU of the brake fluid pressure control device.

FIG. 5 is a map conceptually showing a valve opening pressure determination table stored in a ROM of the brake ECU.

FIG. 6 is a flowchart showing a main control program stored in a ROM of the brake ECU.

FIG. 7 is a flowchart showing a precharge control program stored in a ROM of the brake ECU.

FIG. 8 is a flowchart showing a stop control program stored in a ROM of the brake ECU.

FIG. 9 is a diagram showing a relationship between a hydraulic fluid amount and a hydraulic pressure in a brake cylinder.

FIG. 10 is a diagram showing an example of precharge control by the brake fluid pressure control device.

FIG. 11 is a diagram showing an example of control at stop by the brake fluid pressure control device.

FIG. 12 is a map showing a hydraulic pressure control table of a brake cylinder stored in a ROM of a brake ECU of a brake hydraulic pressure control device according to another embodiment of the present invention.

[Explanation of symbols]

12 pump devices 100-106 linear valve device 160 brake ECU

Claims (7)

[Claims] 1. A pressure increase control valve provided between a brake cylinder of a hydraulically actuated brake and a high pressure source, a pressure reduction control valve provided between the brake cylinder and a low pressure source, and A controller for controlling the hydraulic pressure of the brake cylinder by controlling at least one of a pressure increase control valve and a pressure reducing control valve, the controller controlling the hydraulic pressure of the brake cylinder to a desired magnitude. Before the control section starts its control of at least one of the pressure increase control valve and the pressure reduction control valve by the main control section, the flow rate of the hydraulic fluid flowing through at least one of the control section at the start of control by the main control section is A brake fluid pressure control device, comprising: an auxiliary control unit that controls the state of the brake cylinder so that the brake fluid pressure becomes smaller than that when the brake fluid pressure control is not performed. 2. The brake suppresses rotation of the wheel by pressing a friction engagement member against a brake rotating body that is rotated integrally with the wheel by hydraulic pressure of the brake cylinder, and the auxiliary control. The brake fluid pressure control device according to claim 1, wherein the portion includes a friction engagement member approaching portion that causes the friction engagement member to approach the brake rotating body by supplying hydraulic fluid to the brake cylinder. 3. The approach position corresponding liquid for controlling the hydraulic pressure of the brake cylinder as the state of the brake cylinder based on the relative position of the friction engaging member with respect to the brake rotating body. The brake fluid pressure control device according to claim 2, further comprising a pressure control unit. 4. The auxiliary control section, when the brake is not in operation and there is no brake operation request by the main control section, and there is a high possibility that a brake operation request will occur in the near future, 4. The brake hydraulic pressure control device according to claim 1, further comprising a brake operation predicted control starting unit that starts controlling the hydraulic pressure of the brake cylinder. 5. The brake hydraulic pressure control device according to claim 1, wherein the auxiliary control unit includes a pattern control unit that controls the hydraulic pressure of the brake cylinder according to a preset setting pattern. . 6. The auxiliary control section includes a vehicle stop control start section for starting control of hydraulic pressure of the brake cylinder when the traveling speed of the vehicle is reduced to a set speed or lower due to operation of the brake. The brake fluid pressure control device according to any one of claims 1 to 5. 7. The brake hydraulic pressure according to claim 6, wherein the auxiliary control section includes a brake hydraulic pressure suppressing section that makes the hydraulic pressure of the brake cylinder smaller than a magnitude corresponding to an operation state amount of the brake operating member. Control device.