JPH10329675A - Hydraulic brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a deceleration reflecting the intention of a driver in an emergency brake operation in a hydraulic brake device which generates a large braking force, compared with a general time when the emergency brake operation is performed. SOLUTION: In this device, BA control is started at a time t1 deceleration αis increased toward a target deceleration α0 according to the increase in wheel cylinder pressure PW/ C. When the deceleration α reaches α1 at a time t3 , the increasing gradient of the wheel cylinder pressure PW/ C is reduced, and when α reaches a prescribed value α2 at a time t4 , PW/ C is held thereafter. When master cylinder pressure PM/ C is raised at a time t5 , an increase in operation of a brake pedal is judged, and the target deceleration α0 is increased. The wheel cylinder pressure PW/ C is also increased according to this, whereby the deceleration α is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake device, and more particularly to a braking force control device that generates a greater braking force than usual when an emergency braking operation is performed on a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 49, there is known a hydraulic brake device that generates a larger braking force than usual when an emergency brake operation is performed. The conventional hydraulic brake device includes an emergency brake operation detecting unit that detects an emergency brake operation, a hydraulic pressure generating mechanism that generates a high assist pressure, and a wheel cylinder that is either a master cylinder or a hydraulic pressure generating mechanism. And a hydraulic control means for communicating.

[0003] In the above conventional apparatus, when the emergency brake operation is not detected, the hydraulic pressure control means connects the wheel cylinder to the master cylinder. in this case,
The brake pressure is supplied to the wheel cylinder, whereby normal brake control is realized. Further, when it is detected that the emergency brake operation has been performed, the hydraulic pressure control means connects the wheel cylinder to the hydraulic pressure generating mechanism. In this case, the high pressure generated by the hydraulic pressure generating mechanism is supplied to the wheel cylinder, so that the wheel cylinder pressure is increased to a maximum value. Therefore, according to the above-described conventional apparatus, when an emergency brake operation is detected, a large deceleration can be realized regardless of the magnitude of the brake pedaling force.

[0004]

By the way, even under an emergency braking operation, depending on the road surface condition during running, the running condition such as turning or straight running, etc. The magnitude of the deceleration desired by the driver varies. However, as described above, the conventional device is configured to uniformly increase the wheel cylinder pressure to a maximum value when an emergency brake operation is detected. For this reason, according to the above-mentioned conventional device, the deceleration cannot be changed according to the driver's intention after the emergency braking operation is performed.

[0005] The present invention has been made in view of the above points, and provides a hydraulic brake device capable of realizing deceleration reflecting the driver's intention when an emergency brake operation is performed. The purpose is to provide.

[0006]

The above object is achieved by the present invention.
As described in the above, normally, a brake fluid pressure is generated according to the brake depression force, and when an emergency brake operation is performed, the brake fluid pressure is controlled to achieve a predetermined target deceleration. The present invention is achieved by a hydraulic brake device including: a control unit; and a target deceleration changing unit that changes the predetermined target deceleration according to an operation amount of a brake pedal after an emergency brake operation is performed.

In the present invention, the hydraulic pressure control means controls the brake hydraulic pressure such that a predetermined target deceleration is realized when an emergency brake operation is performed. The target deceleration is changed by the target deceleration changing means in accordance with the operation amount of the brake pedal after the emergency brake operation is performed. The operation amount of the brake pedal reflects the intention of the driver to decelerate. Therefore, according to the present invention, when an emergency brake operation is performed, deceleration reflecting the driver's intention is realized.

[0008]

FIG. 1 is a system configuration diagram of a hydraulic brake device according to an embodiment of the present invention. The hydraulic brake device of the present embodiment is controlled by an electronic control unit (hereinafter, referred to as ECU) not shown. FIG. 1 shows components for realizing a brake mechanism for the left front wheel FL and the right rear wheel RR.

The brake device shown in FIG. 1 has a brake pedal 10. The brake pedal 10 is connected to an operation shaft 14 of a brake booster 12. A master cylinder 16 is fixed to the brake booster 12. The master cylinder 16 has a hydraulic chamber inside. In the hydraulic chamber of the master cylinder 16, a master cylinder pressure PM _{/ C} having a predetermined boosting ratio with respect to the brake depression force applied to the brake pedal 10 is generated.

A reservoir tank 18 is provided above the master cylinder 16. A predetermined amount of brake fluid is stored inside the reservoir tank 18. When the depression of the brake pedal is released, the hydraulic pressure chamber of the master cylinder 16 and the reservoir tank 18 are in communication. A hydraulic passage 20 is connected to the hydraulic chamber of the master cylinder 16. A hydraulic pressure sensor 22 communicates with the hydraulic pressure passage 20. The output signal of the oil pressure sensor 22 is supplied to the ECU. The ECU detects the master cylinder pressure P _{M / C} based on the output signal of the oil pressure sensor 22.

An electromagnetic valve 24 communicates with the hydraulic passage 20. The solenoid valve 24 is a two-position, three-way solenoid valve including a first port 26, a second port 28, and a third port 30. The first port 26 communicates with the hydraulic passage 20. The second port 28 communicates with the hydraulic passages 40 and 41. The third port 30 is in communication with the hydraulic passage 42. The solenoid valve 24 realizes a first state in which the first port 26 and the second port 28 are electrically connected and the third port 30 is closed in a state where no drive signal is supplied from the ECU, that is, in an off state. On the other hand, in a state where the drive signal is supplied from the ECU, that is, in the ON state, the second state in which the first port 26 and the third port 30 are electrically connected and the second port 28 is closed is realized.

Between the hydraulic passage 20 and the hydraulic passage 40,
In parallel with the solenoid valve 24, a check valve 32 and a relief valve 34
Are arranged. The check valve 32 is a one-way valve that allows only the flow of the fluid from the hydraulic passage 20 to the hydraulic passage 40. The relief valve 34 is a valve mechanism that opens only when the hydraulic pressure on the hydraulic pressure passage 40 side is higher than a hydraulic pressure on the hydraulic pressure passage 20 side by a predetermined value or more.

In the hydraulic passage 40, a holding solenoid 44,
46 and check valves 48 and 50 are in communication. The holding solenoids 44 and 46 are two-position solenoid valves that are closed when a drive signal is supplied from the ECU. The holding solenoid 44 and the check valve 48 communicate with the wheel cylinder 52 of the right rear wheel RR. The check valve 48 is a one-way valve that allows only the flow of fluid from the wheel cylinder 52 to the hydraulic passage 40. Further, the holding solenoid 46 and the check valve 50 communicate with the wheel cylinder 54 of the left front wheel FL. The check valve 50 is a one-way valve that allows only the flow of the fluid from the wheel cylinder 54 toward the hydraulic passage 40.

The wheel cylinders 52 and 54 are connected to pressure reducing solenoids 56 and 58, respectively. The pressure reducing solenoids 56 and 58 are two-position solenoid valves that are opened when a drive signal is supplied from the ECU.
The pressure reducing solenoids 56 and 58 are both connected to the auxiliary reservoir 60.
Is in communication with The suction side of a pump 64 communicates with the auxiliary reservoir 60 via a check valve 62. The discharge side of the pump 64 communicates with the hydraulic passage 41 via a check valve 66. The pump 64 is activated when a drive signal is applied to the pump motor 65. Check valve 62
Is a one-way valve that allows only the flow of fluid from the auxiliary reservoir 60 toward the pump 64. Check valve 6
Reference numeral 6 denotes a one-way valve that allows only the flow of the fluid from the pump 64 toward the hydraulic passage 41.

Inside the auxiliary reservoir 60, a piston 6
8 and a spring 70 are provided. Piston 68
Is biased by a spring 70 in a direction in which the volume of the auxiliary reservoir 60 decreases. The auxiliary reservoir 60 has
A reservoir port 72 communicating with the hydraulic passage 42 is provided. A ball valve 74 is provided inside the reservoir port 72.
And a pressing shaft 76 are provided. Further, the reservoir port 72 is provided with a seat portion 78 that functions as a valve seat of the ball valve 74. Both ends of the pressing shaft 76 are in contact with the piston 68 and the ball valve 74, respectively.

When no brake fluid flows into the auxiliary reservoir 60, the piston 68 is located at the uppermost position (hereinafter, referred to as an original position) in FIG. Inside the auxiliary reservoir 60, a hydraulic path for ensuring conduction between the hydraulic passage 42, the pressure reducing solenoids 56 and 58, and the check valve 62 when the piston 68 is at the original position is secured.

When the piston 68 is at the home position,
The ball valve 74 moves away from the seat 78. Ball valve 7
The clearance formed between 4 and the seat portion 78 is
The amount decreases as the amount of brake fluid stored in the auxiliary reservoir 60 increases, that is, as the amount of displacement of the piston 68 increases. And the auxiliary reservoir 60
When the amount of brake fluid stored in the vehicle reaches a predetermined value, the ball valve 74 is seated on the seat portion 78. When the ball valve 74 is seated on the seat portion 78, the hydraulic pressure passage 4
The flow of the brake fluid from 2 into the auxiliary reservoir 60 is prevented.

The hydraulic brake device shown in FIG. 1 has a function as a normal brake device (hereinafter, referred to as a normal brake function), an ABS function for preventing an excessive slip ratio from occurring on wheels during a brake operation, Also, when an emergency braking operation is performed by the driver, a brake assist function (hereinafter, referred to as B
A function).

As shown in FIG. 1, the normal brake function is as follows: the solenoid valve 24 is turned off, the holding solenoids 44 and 46 are opened, the pressure reducing solenoids 56 and 58 are closed, and the pump 64 is stopped. This is realized by setting the state. Hereinafter, this state is referred to as a normal brake state. When the normal braking state is realized, the master cylinder 16 and the wheel cylinders 52 and 54 are brought into conduction. in this case,
Wheel cylinder pressure P _{W / C} of wheel cylinders 52 and 54 is controlled to a hydraulic pressure equal to master cylinder pressure P _{M / C.} Therefore, when the normal braking state is realized, the braking force generated in the vehicle is controlled to a magnitude corresponding to the brake depression force.

The ABS function is such that when the brake pedal 10 is depressed, the solenoid valve 24 is turned off, the pump 64 is operated, and the holding solenoid 44,
46 and the pressure reducing solenoids 56 and 58 are appropriately opened and closed. Hereinafter, this state is referred to as an ABS state. When the solenoid valve 24 is turned off while the brake pedal 10 is being depressed, the master cylinder pressure PM _{/ C} is guided to the hydraulic passage 40. When the master cylinder pressure PM _{/ C} is guided to the hydraulic pressure passage 40 and the holding solenoid 44 is opened and the pressure reducing solenoid 56 is closed (the state shown in FIG. 1), Wheel cylinder 52 and master cylinder 16 are brought into conduction. That is, the wheel cylinder pressure P _{W / C} is increased toward the master cylinder pressure P _{M / C.} This state is hereinafter referred to as a pressure increase mode. When both the holding solenoid 44 and the pressure reducing solenoid 56 are closed, the wheel cylinder pressure PM _{/ C} is held. This state is hereinafter referred to as a holding mode. Further, when the pressure increasing solenoid 44 is closed and the pressure reducing solenoid 52 is opened, the wheel cylinder 52 and the auxiliary reservoir 60 are electrically connected. In this case, the brake fluid in the wheel cylinder 52 flows out toward the auxiliary reservoir 60, so that the wheel cylinder pressure is reduced. This state is hereinafter referred to as a decompression mode.

Similarly, for the wheel cylinder 54,
By appropriately opening and closing the holding solenoid 46 and the pressure reducing solenoid 58, the pressure increasing mode, the holding mode, and the pressure reducing mode can be realized. In the hydraulic brake device of the present embodiment, the above-described pressure increasing mode, holding mode, and pressure reducing mode are appropriately realized so that the wheel slip ratio does not exceed a predetermined value. Therefore, when the ABS control is started, the locking tendency of the wheels RR and FL is converged.

In the decompression mode, the brake fluid flowing into the auxiliary reservoir 60 is pumped up by the hydraulic pump 64 and supplied to the hydraulic passage 40. Therefore,
In the ABS state, the amount of brake fluid in the hydraulic system from the master cylinder 16 to the wheel cylinders 52, 54 is prevented from decreasing. The BA function turns on the solenoid valve 24 when the brake pedal 10 is depressed at an operation speed exceeding a predetermined value, and the boosting solenoid 4
This is realized by setting the valves 4 and 46 to the open state, setting the pressure reducing solenoids 56 and 58 to the closed state, and setting the pump 64 to the operating state. This state is hereinafter referred to as a BA state. Further, control for realizing the BA state is hereinafter referred to as BA control.

When the solenoid valve 24 is turned on while the brake pedal 10 is being depressed, the master cylinder 16 and the auxiliary reservoir 60 are brought into conduction. When the master cylinder 16 and the auxiliary reservoir 60 are electrically connected, the brake fluid flows from the master cylinder 16 into the auxiliary reservoir 60 until the ball valve 74 is seated on the seat 78. Then, the brake fluid flowing into the auxiliary reservoir 60 is pumped up by the pump 64 and supplied to the hydraulic passage 40. Therefore, when the BA control is started, a high-pressure brake fluid is guided to the hydraulic pressure passage 40 by using the pump 64 as a hydraulic pressure source.

The high-pressure brake fluid guided to the hydraulic passage 40 during the execution of the BA control is supplied to the holding solenoids 44, 4
6 are led to wheel cylinders 52, 54, respectively. Therefore, when the BA control is started, the wheel cylinder pressure quickly increases to a higher fluid pressure than the master cylinder pressure. As described above, according to the BA control, the deceleration α of the vehicle can be quickly increased after the emergency brake operation is started.

In the hydraulic brake system of the present embodiment, B
When the deceleration α of the vehicle reaches the predetermined target acceleration α ₀ during the execution of the A control, the wheel cylinder pressure P _{W / C} is kept constant, so that the deceleration α of the vehicle becomes the target deceleration α _0. Is held. The wheel cylinder pressure P _{W / C} is maintained during the BA control by controlling the solenoid valve 24 to be turned on and off. Hereinafter, a state realized by performing on / off control of the solenoid valve 24 in the present embodiment will be described.

In the system shown in FIG.
Is turned on, the wheel cylinders 52, 54 and the pump 64 are brought into conduction, and the master cylinder 16, the wheel cylinders 52, 54 and the pump 64 are turned off. Therefore, during execution of the BA control, the solenoid valve 2
4 is turned on, the wheel cylinders 52, 54
, A brake fluid having a flow rate equal to the discharge flow rate Q ₀ of the pump 64 flows thereinto.

On the other hand, when the solenoid valve 24 is turned off,
In this case, the master cylinder 16 and the wheel cylinders 52, 54
Becomes conductive, and the pump 64 and the master cylinder
16 and the wheel cylinders 52 and 54 are electrically connected.
You. During the execution of the BA control, the wheel cylinder pressure P
_{W / C}Is the master cylinder pressure P _{M / C}High pressure compared to
You. Therefore, during the execution of the BA control, the master cylinder 1
6 and the wheel cylinders 52 and 54 are brought into conduction,
From the wheel cylinders 52, 54 to the master cylinder 16,
Flow rate Q according to the pressure difference between the two₁Brake fluid flows
Put out. Further, the pump 64, the master cylinder 16 and
When the wheel cylinders 52 and 54 are electrically connected,
The brake fluid discharged by the pump 64 is a wheel cylinder
Flow into master cylinder 16 as well as 52 and 54
I do. In this case, from the pump 54 to the master cylinder 16
The flow rate of the incoming brake fluid is Q_TwoThen
From the pump 54 to the wheel cylinders 52, 54 (Q₀−
Q_Two) Will flow in.

That is, during the execution of the BA control, the solenoid valve 24
Are turned off, the wheel cylinders 52, 54
To the master cylinder 16₁Brake fluid
While flowing out, the wheel cylinders 52, 5
Flow rate to 4 (Q₀−Q_Two) Brake fluid flows in
You. Therefore, with the solenoid valve 24 turned off, the wheel
Total flow of brake fluid flowing out of the Linda 52, 54
The quantity is (Q₁−Q₀+ Q _Two).

Thus, the state in which the solenoid valve 24 is turned on
Then, the flow rate Q₀Brake
Fluid flowed in, while solenoid valve 24 was turned off
In the state, the flow rate (Q₁−
Q₀+ Q_Two) Brake fluid leaks out. Foil
Linda pressure P_{W / C}And master cylinder pressure P_{M / C}Is kept constant
If held, the flow rate Q₀, Q₁, And Q_TwoMoichi
It will be fixed. Therefore, the on / off control of the solenoid valve 24 is not possible.
And the brakes flowing into the wheel cylinders 52 and 54
Kifluid flow rate Q₀Time average q_IN(Hereafter, average inflow
Flow rate q_INAnd the wheel cylinders 52 and 54
Of brake fluid flowing out ₁−Q₀+
Q_Two) Time average q_OUT(Hereinafter, average outflow q_OUTWhen
) Can be varied. And the average inflow
Quantity q_INAnd average outflow q_OUTSo that
The on / off duty ratio of the magnetic valve 24 is set.
Brake full for wheel cylinders 52 and 54
When the balance of the flow rate of the
Cylinder pressure P_{W / C}Form a state that is kept constant
be able to. Such a state is hereinafter referred to as an equilibrium holding mode.
Name.

As described above, the BA control is a brake control executed to increase the deceleration quickly when an emergency brake operation is performed. However, B
Even during the execution of the A-control, the magnitude of the deceleration desired by the driver is not constant, and varies depending on the road surface conditions during traveling and the traveling state such as whether the vehicle is turning or traveling straight. I do. The hydraulic brake device according to the present embodiment is characterized in that a deceleration reflecting the driver's intention can be realized during the execution of the BA control.

FIG. 2 exemplifies a time change of the master cylinder pressure P _{M / C} , the wheel cylinder pressure P _{W / C} , and the deceleration α of the vehicle realized by the hydraulic brake device of the present embodiment. In FIG. 2, the predetermined values α ₁ and α ₂ are set so as to have predetermined ratios a and b with respect to the target deceleration α ₀ , that is, α ₁ = a · α ₁ and α ₂ = B
A value set to be α ₀ . Here, b is a value sufficiently close to 1, and a relationship of 1>b> a is established. Further, in a state before the BA control is started, the target deceleration α ₀ is set to a predetermined initial value.

In the situation illustrated in FIG. 2, at time t₁
At the master cylinder pressure P_{M / C}Is a predetermined value
The emergency brake operation was detected
Have been. Therefore, the time t₁BA control starts at
And thereafter the wheel cylinder pressure P_{W / C}Increases with a large gradient
It is under pressure. Wheel cylinder pressure P_{W / C}With increasing pressure
Thus, the deceleration α also increases quickly. Also, BA control
Starts at time t _TwoUntil the brake pedal 10
The master cylinder pressure P_{M / C}Rises
The target deceleration α₀Has been increased
I have. And time t_TwoAt the master cylinder pressure P
_{M / C}Is completed, the target deceleration α₀Is constant
Maintained at the value.

Time t_Three, The deceleration α is a predetermined value α₁
And the deceleration α becomes the target deceleration α ₀And approached
Is determined. Therefore, the time t_ThreeThereafter, the deceleration α
Crab target deceleration α₀To reach the wheel cylinder
Pressure P_{W / C}Is increased. Time t_ThreeLater
Wheel cylinder pressure P_{W / C}Of the pressure increase gradient of the pump
The drive signal supplied to the motor 65 is controlled on / off.
Is realized by: Drive to supply to pump motor 65
When the signal is on / off controlled, the pump motor 65
The number of turns is lower than when a continuous drive signal is applied.
Down. When the rotation speed of the pump motor 65 decreases, the pump
The discharge flow rate of the pump 64 decreases. And the discharge of the pump 64
When the outflow rate decreases, it flows into the wheel cylinders 52 and 54
Brake fluid flow is reduced. Therefore,
ON / OFF control of the drive signal supplied to the stepper motor 65
The wheel cylinder pressure P_{W / C}The pressure gradient of
Can be

[0034] Thus, the time t ₃ after, that the wheel cylinder pressure P _{W / C} of the pressure increase gradient is reduced, the deceleration α now increases at a gradual gradient, at time t _4,
α ₂ has been reached. As described above, α ₂ is set to a value substantially equal to the target acceleration α ₀ . Therefore, the deceleration α
Reaches α ₂ , it is determined that the target deceleration α ₀ has been achieved. Therefore, the time t ₄ after the wheel cylinder pressure P _{W / C} by the equilibrium holding mode is formed is held, thereby, the deceleration alpha is maintained at alpha _2.

[0035] Then, at time t _5, the master cylinder pressure P _{M / C} is started to rise. Master cylinder pressure P
_{When the M / C} increases, it is determined that the driver is stepping on the brake pedal 10, that is, it is determined that the driver desires a larger deceleration. In this case, the target deceleration α ₀ is increased on condition that there is room for an increase in the braking force that can be generated by the tire. When the target deceleration α ₀ is increased,
Α ₂ is accordingly increased. Therefore, after time t _5, by being boosted again the wheel cylinder pressure P _{W / C,} deceleration alpha is increased so as to follow the alpha _2.

Time t₆At the master cylinder pressure P
_{M / C}When the climb is finished, the driver increases the deceleration further
It is determined that the user does not want to make it. For this reason,
Time t ₆Thereafter, the target deceleration α₀Is kept constant and the time
t₇Deceleration α is α_TwoIs reached,
Il cylinder pressure P_{W / C}Is retained. As mentioned above,
In the embodiment, when the BA control is started, the acceleration α becomes
Target deceleration α₀Foil cillin as it increases towards
Da pressure P_{W / C}Is increased. In this case, immediately after the start of BA control
Later, wheel cylinder pressure P_{W / C}Increases with a relatively large gradient
And the deceleration α becomes the target acceleration α₀When approaching
Acceleration α increases quickly due to reduced gradient
And the target acceleration α₀Of acceleration α when reaching
It is possible to suppress the increase gradient. Therefore,
According to the hydraulic brake device of the present embodiment, for the occupant,
Gives a sense of incongruity due to a sudden change in the rate of change of the deceleration α
Immediately after an emergency brake operation is performed
Target deceleration α₀Can be achieved.

In this embodiment, if the driver depresses the brake pedal 10 during the execution of the BA control, the target deceleration α ₀ is increased. Therefore, according to the present embodiment, when the driver desires a larger deceleration during the execution of the BA control, the deceleration can be increased according to the intention. As described above, according to the hydraulic brake device of the present embodiment, the deceleration reflecting the driver's intention can be realized even during the execution of the BA control.

The above functions of the hydraulic brake system according to the present embodiment are realized by the ECU executing a predetermined routine. Hereinafter, the contents of processing executed by the ECU to realize the above functions will be described with reference to FIG. FIG. 3 is a flowchart of a routine executed by the ECU. The routine shown in FIG. 3 is repeatedly executed at predetermined time intervals until a condition for starting the BA control (hereinafter, referred to as a BA start condition) is satisfied.

When the routine shown in FIG. 3 is started, first, the process of step 98 is executed. In step 98, it is determined whether a BA start condition is satisfied, that is, whether an emergency brake operation has been performed. If it is determined in step 98 that the BA start condition is not satisfied, the current routine is terminated without performing any processing. On the other hand, if the BA start condition is satisfied in step 98, the process for executing the BA control is performed in step 100 and thereafter.

In step 100, it is determined whether or not α / α ₀ > a holds, that is, whether or not α> α ₁ holds. As a result, if α / α ₀ > a is not established, it is determined that the deceleration α has not yet reached a sufficient _{value with} respect to the target deceleration α ₀ , and then the processing of step 102 is executed. You. In step 102, processing for forming the BA state, that is, processing for turning on the pump 64 and turning on the solenoid valve 24 is executed. When the processing in step 102 is completed, in step 104, the conditions for ending the BA control (hereinafter, referred to as BA conditions)
It is determined whether or not a BA termination condition is satisfied.
Such a determination can be made, for example, based on whether the master cylinder pressure PM _{/ C} has dropped below a predetermined value. If the BA termination condition is satisfied in step 104, then in step 106, processing for terminating the BA control, that is, processing for turning off the pump 64 and turning off the solenoid valve 24 is executed. After that, this routine is ended. On the other hand, step 104
If the BA termination condition is not satisfied in step
00 is executed. Therefore, until α / α ₀ > a is satisfied in step 100, the wheel cylinder pressure P _{W / C} is increased with a relatively large gradient by maintaining the BA state unless the BA termination condition is satisfied. . On the other hand, if α / α ₀ > a is satisfied in step 100, it is determined that the deceleration α has approached the target deceleration α ₀ , and the process of step 108 is executed next.

In step 108, the master cylinder pressure P
_{M / C}Time change rate ΔP_{M / C}(= DP _{M / C}/ Dt) is specified
It is determined whether the value is smaller than the value β. As a result, Δ
P_{M / C}If <β holds, the master cylinder pressure P_{M / C}
Has not risen. In this case, the brake pedal
Le 10 is not stepped up, so the driver has no braking
Is determined not to increase, then step 110
Is performed. In step 110, the pump mode
The on / off control of the heater 65 is started. Pump motor 6
5 is turned on and off, as described above,
Cylinder pressure P_{W / C}Pressure gradient P_{W / C}Is reduced. one
In step 108, ΔP_{M / C}<Β does not hold
The brake pedal 10 has been depressed further,
Therefore, it is determined that the driver wants to increase the braking force.
Then, the process of step 112 is executed.

In step 112, it is determined whether or not the reference wheel slip ratio s is smaller than a predetermined value C. Here, the reference wheel is any one of the four wheels, and a wheel in which a slip easily occurs is selected as the reference wheel in consideration of a load distribution or the like. . If it is determined in step 112 that s <C is satisfied, it is determined that there is sufficient margin for the braking force that can be generated by the tire.
At 14, the target deceleration α ₀ is increased by a predetermined value d. When the processing of step 114 is completed, the processing of step 100 is executed again. On the other hand, step 112
In, if s <C is not satisfied, it is determined that there is not enough room for the braking force that can be generated by the wheels. In this case, the pressure increase gradient of the wheel cylinder pressure P _{W / C} is reduced by executing the process of step 110 next.

When the process of step 110 is completed, the next
Then, the process of step 116 is performed. Step 11
In 6, α / α₀> B, ie, α
> Α _TwoIs determined. As a result, α /
α₀> B, the deceleration α is almost the target deceleration
α₀Has been reached, and then the processing of step 118 is performed.
Is executed. In step 118, the balance mode
Is formed, the wheel cylinder pressure P_{W / C}But one
Is kept constant. The process of step 118 ends.
Then, the process of step 104 is executed. On the other hand,
In step 116, α / α₀If> b does not hold,
The deceleration α is still the target deceleration α₀Determined to have not reached
It is. In this case, step 114 is skipped and the next
Then, the process of step 104 is executed.

In step 104, it is determined whether the BA end condition is satisfied as described above. As a result, BA
If the end condition is satisfied, the process for terminating the BA control is executed in step 106, and then this routine is ended. On the other hand, if the BA termination condition is not satisfied in step 104,
Is performed.

As described above, according to the routine shown in FIG. 3, after the BA start condition is satisfied, the vehicle deceleration α is controlled to be equal to the target deceleration α ₀ until the BA end condition is satisfied. When the brake pedal 10 is further depressed, the deceleration α can be changed according to the driver's intention by increasing the target acceleration α ₀ .

In the above embodiment, the target deceleration α ₀ is increased when the brake pedal 10 is further depressed during the execution of the BA control. However, the present invention is not limited to this. Not brake pedal 1
When 0 is further increased, the target deceleration α ₀ may be increased, and when the brake pedal 10 is returned, the target deceleration α ₀ may be decreased.

In the above embodiment, it is determined whether or not the brake pedal 10 is further depressed based on the master cylinder pressure PM _{/ C.} However, the present invention is not limited to this. Instead, a pedaling force sensor for detecting the pedaling force applied to the brake pedal 10 may be provided, and the same determination may be made based on the output signal.

In the above embodiment, the ECU executes steps 98 to 106, 110, 1 in the routine shown in FIG.
By executing the processing of Steps 16 and 118, the above-described hydraulic control means realizes the above-described target deceleration changing means by executing the processing of Steps 108 and 114, respectively.

[0049]

As described above, according to the present invention, when an emergency brake operation is performed, the target deceleration can be changed according to the operation amount of the brake pedal. Therefore, according to the hydraulic brake device of the present invention, the deceleration reflecting the driver's intention can be realized during the emergency braking operation.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a hydraulic brake device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a time change of a master cylinder pressure P _{M / C} , a wheel cylinder pressure P _{W / C} , and a vehicle acceleration α realized by the hydraulic brake device of the present embodiment.

FIG. 3 is a flowchart of a routine executed by an ECU in the embodiment.

[Explanation of symbols]

 10 Brake pedal 16 Master cylinder 52, 54 Wheel cylinder 64 Pump

Claims (1)

[Claims] 1. Normally, a brake fluid pressure is generated in accordance with a brake depression force, and when an emergency brake operation is performed, a brake fluid pressure is controlled so that a predetermined target deceleration is realized. A hydraulic brake device comprising: a control unit; and a target deceleration changing unit that changes the predetermined target deceleration according to an operation amount of a brake pedal after an emergency brake operation is performed.