JP3436051B2 - Braking force control device - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-4-12126
As disclosed in No. 0, there is known a braking force control device for increasing a boosting ratio of a brake booster when a brake pedal is depressed at a speed exceeding a predetermined speed. The driver of the vehicle operates the brake pedal at high speed in order to quickly raise the braking force. According to the above-mentioned conventional braking force control device, when such a braking operation (hereinafter referred to as an emergency braking operation) is performed, a large boost ratio is generated as compared with the normal time, so that the braking force is quickly raised. An advantageous state can be formed in raising. Therefore, according to the conventional braking force control device described above, when the driver performs an emergency braking operation, it is possible to appropriately generate the braking force that meets the driver's request.

[0003]

However, the braking force required by the driver when the brake pedal is depressed at a speed exceeding the predetermined speed is not always constant. That is, when the operation speed of the brake pedal is approximately equal to the predetermined speed and when the operation speed is sufficiently higher than the predetermined speed, in the latter case, the driver can apply the braking force more quickly. It can be judged that the intention is to raise it. Therefore, when an emergency braking operation is performed,
In order to generate the braking force that accurately reflects the driver's intention, it is appropriate to change the rising tendency of the braking force according to the brake operating speed generated during the emergency braking operation.

As described above, the conventional braking force control device generates a larger braking force than in the normal state by constantly changing the boosting ratio of the brake booster when the emergency braking operation is performed. . Therefore, the conventional braking force control device described above cannot generate the braking force that reflects the driver's intention when the emergency braking operation is executed.

The present invention has been made in view of the above points, and is capable of generating a braking force that reflects the driver's intention when the driver performs an emergency braking operation. An object is to provide a control device.

[0006]

The above-mentioned object is defined in claim 1.
As described in (4), in a braking force control device that generates a larger braking hydraulic pressure than a normal time when an emergency braking operation is performed by a driver, an operating speed detecting means for detecting a braking operation speed, and the operating speed. By detection means
An emergency brake operation detecting means for detecting execution of an emergency braking operation based on the detected brake operating speed, the
Brake operation speed detected by operation speed detection means
When the braking force falls within the specified range,
In the standby state, the braking force control device is in the standby mode.
The emergency braking operation detecting means.
When an emergency braking operation is detected, a braking oil pressure increasing means for generating a larger braking oil pressure than the normal time by an assist pressure corresponding to the brake operation speed generated in the process of the emergency braking operation is provided. Achieved by the controller.

According to the present invention, execution of an emergency braking operation
When determining the
By setting the lower limit and upper limit
The above lower limit to determine the possibility of emergency braking.
It can be turned off, and the upper limit of
Impacts can be excluded. In the present invention,
If the brake operation speed is relatively low during the emergency brake operation, it can be determined that the driver intends to start the braking force relatively gently. On the other hand, when the brake operation speed is relatively high during the emergency brake operation, it can be determined that the driver intends to quickly raise the braking force. The braking hydraulic pressure increasing means increases the assist pressure applied to the braking hydraulic pressure when the emergency braking operation is executed in accordance with the braking operation speed detected during the emergency braking operation when the braking operation speed is high, Further, when the brake operation speed is low, it is determined to be small. When the braking hydraulic pressure is controlled as described above, the braking force is after the emergency braking operation is performed.
Immediately rise to the value intended by the driver.

The above-mentioned object is as described in claim 2.
The braking force control device according to claim 1, wherein the braking hydraulic pressure increasing means increases the braking hydraulic pressure at a predetermined change rate regardless of whether or not a brake operation is performed, and an assist pressure generating means.
When an emergency braking operation is detected, a braking force including an assist time control means for increasing the braking hydraulic pressure by the assist pressure generating means for a pressure increase time corresponding to the brake operation speed generated in the process of the emergency braking operation. It is also achieved by the control device.

In the present invention, the assist pressure applied to the braking hydraulic pressure when the emergency braking operation is detected is generated by the first assist pressure generating means. The pressure increasing time by the first assist pressure generating means is long when the brake operating speed is high based on the brake operating speed generated during the emergency braking operation, and the brake operating speed is low. If it is set short. In this case, the braking force immediately rises to the value required by the driver after the emergency braking operation is executed.

The above object is as described in claim 3.
The braking force control device according to claim 1, wherein the braking hydraulic pressure increasing means increases the braking hydraulic pressure irrespective of whether or not a braking operation is performed, and an emergency braking operation is detected when an emergency braking operation is detected. A braking force control device comprising: an assist gradient control means for increasing the braking hydraulic pressure by the second assist pressure generating means for a predetermined pressure boosting time at a pressure boosting gradient according to a brake operation speed generated in the process of brake operation. To be achieved.

In the present invention, the assist pressure applied to the braking hydraulic pressure when the emergency braking operation is detected is generated by the second assist pressure generating means. The pressure increase gradient by the second assist pressure generating means is steep when the brake operation speed is high, and is low when the brake operation speed is high, based on the brake operation speed generated in the process of the emergency brake operation. In some cases, it is set loosely. In this case, the braking force immediately rises to a value intended by the driver after the emergency braking operation is performed.

Further, as described in claim 4, the above-mentioned object is, in the braking force control device according to claim 2, wherein the first assist pressure generating means is a predetermined hydraulic pressure as a hydraulic pressure source of the assist pressure. With an accumulator to store
A braking force control device provided with a pressure increasing time correction means for correcting the pressure increasing time by the first assist pressure generating means based on the braking oil pressure when the pressure increasing of the braking oil pressure is started by the first assist pressure generating means. Also achieved by.

In the present invention, the pressure increasing time by the first assist pressure generating means is longer as the brake oil pressure is higher, and is longer based on the brake oil pressure when the pressure increase of the brake oil pressure is started. The lower the hydraulic pressure, the shorter the correction. The first assist pressure generating means increases the braking hydraulic pressure by using the accumulator as a hydraulic pressure source. When the braking hydraulic pressure is increased using the accumulator as the hydraulic pressure source, the braking hydraulic pressure is increased with a steeper gradient as the differential pressure between the hydraulic pressure and the braking hydraulic pressure stored in the accumulator increases. When the pressure increasing time by the first assist pressure generating means is corrected as described above, a substantially constant assist pressure is always ensured regardless of the level of the braking hydraulic pressure when the pressure increasing is started. In this case, the braking force quickly rises to a value intended by the driver after the emergency braking operation is performed.

[0014]

1 is a system configuration diagram of a hydro-booster type braking force control device (hereinafter, simply referred to as a braking force control device) corresponding to an embodiment of the present invention. The braking force control device of the present embodiment includes an electronic control unit 10 (hereinafter,
It is controlled by the ECU 10).

The braking force control device includes a brake pedal 12. A brake switch 14 is arranged near the brake pedal 12. Brake switch 14
Outputs an ON signal when the brake pedal 12 is depressed. The output signal of the brake switch 14 is E
Supplied to CU10. The ECU 10 determines whether or not the brake pedal 12 is depressed based on the output signal of the brake switch 14.

The brake pedal 12 is the master cylinder 1
It is connected to 6. A reservoir tank 18 is arranged above the master cylinder 16. Reservoir tank 1
A return passage 20 for communicating the brake fluid to the reservoir tank 18 communicates with the valve 8. A supply passage 22 also communicates with the reservoir tank 18. The supply passage 22 communicates with the suction side of the pump 24. On the discharge side of the pump 24, the accumulator passage 26
Are in communication. Accurate passage 26 and supply passage 22
A constant pressure release valve 27 that opens when an excessive pressure is generated in the accumulator passage 26 is provided between and.

A pump 24 is provided in the accumulator passage 26.
Accumulator 28 for storing the hydraulic pressure discharged from the
Are in communication. In the accumulator passage 26,
Upper limit pressure switch 30 and lower limit pressure switch 32
Are connected. The upper limit pressure switch 30 is
Pressure in the muller passage 26 (hereinafter, accumulator pressure P
_ACCOutput) exceeds the specified upper limit, the on output is turned on.
Occur. On the other hand, the lower limit side pressure switch 32 is
BR> lator pressure P_ACCON when exceeds the specified lower limit
Generate output.

The pump 24 has an upper limit value after the lower limit pressure switch 32 outputs an ON output until the upper limit pressure switch 30 outputs an ON output, that is, after the accumulator pressure P _ACC falls below the lower limit value. It is turned on until it reaches. Therefore, the accumulator pressure P _ACC is always maintained between the upper limit value and the lower limit value. A regulator 34 is integrally incorporated in the master cylinder 16. The accumulator passage 26 communicates with the regulator 34. Hereinafter, the master cylinder 16 and the regulator 34 are collectively referred to as a hide booster 36.

FIG. 2 shows a cross-sectional view of the hydrobooster 36. The hydro booster 36 includes a housing 38. A first piston 40 is arranged inside the housing 38. The first piston 40 includes a large diameter portion 42 and a small diameter portion 44. Inside the housing 38, an assist hydraulic pressure chamber 46 is formed on the brake pedal 12 side of the first piston 40, and an atmospheric pressure chamber 48 is formed around the small diameter portion 44. The atmospheric pressure chamber 48 is
It is in constant communication with the reservoir tank 18.

A second piston 50 is arranged inside the housing 38. The second piston 50 has a large diameter portion 5
2 and the spool portion 54. Inside the housing 38, a first hydraulic chamber 56 is formed between the first piston 40 and the second piston 50, and a second hydraulic chamber 58 is formed so as to surround the spool portion 54. The first hydraulic chamber 56 includes a first piston 40 and a second piston 40.
A spring 60 for urging the piston 50 in the separating direction is provided. The second hydraulic chamber 58 communicates with the assist hydraulic chamber 46 via the hydraulic passage 62.

Inside the housing 38, a high pressure passage 64 is formed, one end of which communicates with the accumulator passage 26 and the other end of which opens to the outer peripheral surface of the spool portion 54. The spool portion 54 is displaced leftward in FIG. 1 to bring the high-pressure passage 64 and the second hydraulic chamber 58 into a conductive state, and is displaced rightward in FIG. The hydraulic chamber 58 is shut off.

A valve mechanism 66 is disposed inside the housing 38. The valve mechanism 66 includes a valve seat 68, a valve body 70,
Also, a spring 72 is provided. An atmospheric pressure chamber 74 communicating with the reservoir tank 18 is formed around the valve seat 68. Further, a pressure adjusting passage 76 communicating with the second hydraulic chamber 58 is opened at the end surface of the valve seat 68. Valve seat 68
An oil passage that connects the atmospheric pressure chamber 74 and the pressure adjusting passage 76 is formed inside the. The valve body 70 includes the second piston 50.
1 is the right displacement end in FIG. 1, that is, the oil passage is in a conductive state when it is in the original position, and the second piston 50 is displaced from the original position to the left in FIG. Then, the oil passage is shut off.

Inside the housing 38, the reaction disc 7 is located at a position slightly separated from the end face of the valve mechanism 66.
8 are provided. The reaction disk 78 defines a reaction force chamber 80 inside the housing 38, which communicates with the pressure adjusting passage 76. The reaction disk 78 is composed of a member having elasticity, and when high pressure hydraulic pressure is introduced into the reaction force chamber 80, the reaction disk 78 elastically deforms and abuts the valve mechanism 66.

When the brake pedal force F is not applied to the brake pedal 12, both the first piston 40 and the second piston 50 are held at the original position, that is, at the right displacement end in FIG. In this case, since the pressure regulating passage 76 and the reservoir tank 18 are brought into conduction via the valve mechanism 66, the second hydraulic chamber 58 is regulated to the atmospheric pressure. When the second hydraulic chamber 58 is regulated to the atmospheric pressure, it is formed between the assist hydraulic chamber 46 communicating with the second hydraulic chamber via the hydraulic passage 62 and between the first piston 40 and the second piston 50. Similarly, the pressure of the first hydraulic chamber 56 is adjusted to the atmospheric pressure.

When the brake pedal force F is applied to the brake pedal 12, the first piston 40 and the second piston 50
Displace from their original position to the left in FIG. When the second piston 50 is displaced leftward, the valve mechanism 66 is first closed, and the pressure adjusting passage 76 and the reservoir tank 18 are shut off. When the second piston 50 is further displaced leftward, the high pressure passage 64 and the second hydraulic chamber 58 are brought into conduction via the spool portion 54.

When the high pressure passage 64 and the second hydraulic chamber 58 are brought into conduction, the accumulator pressure P _{AC C} is changed to the second hydraulic chamber 58.
The internal pressure of the second hydraulic chamber 58 (hereinafter, this pressure is referred to as regulator pressure P _RE ) is increased by being guided to. The regulator pressure P _RE is guided to the assist hydraulic chamber 46. Therefore, when the regulator pressure P _RE is increased, the assist force Fa corresponding to the regulator pressure P _RE is applied to the first piston 40 in addition to the brake pedal force F.

Assuming that the area where the regulator pressure P _RE introduced into the assist hydraulic chamber 46 acts on the first piston 40 is S ₁ , the assist force Fa can be expressed by the following equation. Fa = S ₁ × P _RE (1) In this case, the hydraulic pressure corresponding to the brake pedal force F and the regulator pressure P _RE is stored in the first hydraulic chamber 56 (hereinafter, this pressure is referred to as the master cylinder pressure P _{M / C).} Is called) occurs. When the cross-sectional area of the small diameter portion 44 of the first piston 40 is S ₂ , the master cylinder pressure P _{M / C} can be expressed by the following equation using the brake pedal force F and the regulator pressure P _RE .

P _{M / C} = (F + S ₁ × P _RE ) / S ₂ (2) At this time, the force F _{M / C} by which the brake fluid in the first hydraulic chamber 56 presses the second piston 58 is , And the area of the large diameter portion 52 of the second piston 50 is S ₂ , it can be expressed by the following equation. _{F M / C = P M /} C × S 2 = F + S 1 × P RE ··· (3) Furthermore, when the regulator pressure P _RE to the second hydraulic pressure chamber 58 is generated, the brake in the second hydraulic chamber 58 The force F _RE that presses the second piston 58 by the fluid can be expressed by the following equation, where S ₃ is the area where the regulator pressure P _RE in the second hydraulic chamber 58 acts on the second piston 58.

F _RE = P _RE × S ₃ (4) The regulator pressure P _RE generated in the second hydraulic chamber 58 is also guided to the reaction force chamber 80. The second piston 50 has a valve mechanism 66.
2 is displaced to the right in FIG. 2 until the reaction disk 78 comes into contact with the reaction disk 78, the reaction force Fr corresponding to the regulator pressure P _RE is transmitted to the second piston 50 via the reaction disk 78. The reaction force Fr can be expressed by the following equation using a predetermined value K.

Fr = K × P _RE (5) After the brake pedal force F is applied to the brake pedal 12,
F _{M / C} , F _RE , and F shown in the above formulas (3) to (5)
The second piston 50 is displaced from the original position to the left in FIG. 2 while the relationship of the following equation is established for r. F _{M / C} > F _RE + Fr (6) In this case, since the second hydraulic chamber 58 is maintained in the conductive state with the high pressure passage 64, the regulator pressure P _RE gradually increases.

After the brake pedal force F is applied to the brake pedal 12, FM _{/ C} shown in the above equations (3) to (5),
When the state where the relation of the following expression is established is formed in F _RE and Fr, the second piston 50 is pushed back toward the original position. F _{M / C} <F _RE + Fr (7) When the second piston 50 is pushed back toward the original position, the second hydraulic chamber 58 is shut off from the high pressure passage 64, so that the regulator pressure P _RE is increased. Be stopped. Therefore, according to the hydro booster 36, after the brake pedal force is applied to the brake pedal 12, the regulator pressure P _RE is adjusted so that the relationship of the following equation is satisfied.

F _{M / C} = F _RE + Fr (8) The relationship of the expression (8) can be rewritten as the following expression using the relationships of the expressions (3) to (5). In _{P RE = F / (S 3} + K-S 1) ··· (9) the embodiment, the hydro-booster 36, (9) where _{"1 / (S 3 + K} -S 1)" is given It is designed so as to have a booster ratio and the regulator pressure P _RE and the master cylinder pressure P _{M / C} are substantially equal. Therefore, according to the hydro booster 36, when the brake pedal force F is applied to the brake pedal 12, the brake pedal force F is applied to the first hydraulic chamber 56 and the second hydraulic chamber 58.
A hydraulic pressure (master cylinder pressure P _{M / C} and regulator pressure P _RE ) having a predetermined boosting ratio can be generated.

In the following description, the hydraulic pressure generated by the hydrobooster 36, that is, the master cylinder pressure P _{M / C} generated in the first hydraulic chamber 56, and
The regulator pressure P _RE generated in the second hydraulic chamber 58 is generically referred to as the master cylinder pressure P _{M / C.} As shown in FIG. 1, the first hydraulic chamber 56 of the hydro booster 36, and
A first hydraulic pressure passage 82 and a second hydraulic pressure passage 84 communicate with the second hydraulic chamber 58, respectively. First hydraulic passage 8
2 includes a first assist solenoid 86 (hereinafter, SA _-18
6) and the second assist solenoid 88 (hereinafter,
SA- ₂ 88) is in communication. On the other hand, in the second hydraulic pressure passage 84, the third assist solenoid 90 (hereinafter, SA
_-3 90 hereinafter) is communicated with.

SA _-1 86 and SA _-2 88 also include
The control pressure passage 92 communicates. The control pressure passage 92 includes a regulator switching solenoid 94 (hereinafter, referred to as STR94).
(Referred to as “)” and communicates with the accumulator passage 26. When the STR 94 is turned off, the accumulator passage 26 and the control pressure passage 92 are shut off, and when turned on, the STR 94 is turned on.
Position solenoid valve.

A hydraulic pressure passage 96 provided corresponding to the right front wheel FR communicates with the SA _-1 86. Similarly, SA _-2
88 is a hydraulic passage 9 provided corresponding to the left front wheel FL.
8 are in communication. When the SA _-1 86 is turned off, the first hydraulic fluid passage 96 is electrically connected to the first hydraulic fluid passage 82.
It is a two-position solenoid valve that realizes the above state and realizes a second state in which the hydraulic pressure passage 96 is brought into conduction with the control pressure passage 92 by being turned on. In addition, the SA- ₂ 88 realizes a first state in which the hydraulic pressure passage 98 is electrically connected to the first hydraulic pressure passage 82 by being turned off, and is turned on, and the hydraulic pressure passage 98 is turned on. Is a two-position solenoid valve that realizes a second state in which the control valve is connected to the control pressure passage 92.

The SA- ₃ 90 communicates with a hydraulic passage 100 provided corresponding to the left and right rear wheels RL and RR. SA
_-3 90 is a two-position solenoid valve that is turned off to make the second hydraulic passage 84 and the hydraulic passage 100 conductive, and is turned on to shut them off. is there. A check valve 102 is provided between the second hydraulic pressure passage 84 and the hydraulic pressure passage 100 to allow only the flow of fluid from the second hydraulic pressure passage 84 side toward the hydraulic pressure passage 100 side.

In the hydraulic passage 96 corresponding to the right front wheel FR,
A front right wheel holding solenoid 104 (hereinafter referred to as SFRH 104) is in communication. Similarly, in the hydraulic passage 96 corresponding to the left front wheel FL, the left front wheel holding solenoid 106 (hereinafter,
SFLH106), but the right rear wheel holding solenoid 108 is provided in the hydraulic passage 100 corresponding to the left and right rear wheels RL, RR.
(Hereinafter, referred to as SRRH 108) and left rear wheel holding solenoid 110 (hereinafter, referred to as SRLH 110) are in communication with each other. Hereinafter, these solenoids are collectively referred to as "holding solenoid S ** H".

A right front wheel depressurizing solenoid 112 (hereinafter referred to as SFRR 112) communicates with the SFRH 104. Similarly, SFLH 106, SRRH 108 and S
The left front wheel decompression solenoid 11 is provided in each of the RLHs 110.
4 (hereinafter, referred to as SFLR 114), the right rear wheel decompression solenoid 116 (hereinafter, referred to as SRRR 116) and the left rear wheel decompression solenoid 118 (hereinafter, referred to as SRLR 118) are in communication with each other. Hereinafter, these solenoids will be collectively referred to as "pressure reducing solenoid S ** R".

The wheel cylinder 120 for the right front wheel FR is also in communication with the SFRH 104. Similarly, SFL
In H106, the wheel cylinder 122 of the left front wheel FL is
The RRH 108 has a wheel cylinder 124 for the right rear wheel RR.
However, the wheel cylinders 126 of the left rear wheel RL communicate with the SRLH 110, respectively. Furthermore, the hydraulic passage 9
6 between the wheel cylinder 120 and the SFRH 104.
Bypass the wheel cylinder 120 side to the hydraulic passage 9
A check valve 128 is provided which allows the flow of fluid towards the valve 6. Similarly, between the hydraulic passage 98 and the wheel cylinder 122, between the hydraulic passage 100 and the wheel cylinder 124.
Between the hydraulic pressure passage 100 and the wheel cylinder 12
6 and SFLH106 and SRRH10, respectively.
8 and SRLH 110 are provided with check valves 130, 132, 134 which allow the flow of fluid.

The SFRH 104 is a two-position solenoid valve that is turned off to bring the hydraulic passage 96 and the wheel cylinder 120 into conduction, and is turned on to shut them off. Similarly, SFLH
106, SRRH 108, and SRLH 110 are respectively turned on to connect the fluid pressure passage 98 and the foil cinder 122, the fluid pressure passage 100 and the foil cinder 124, and the fluid pressure passage 100 and the foil cinder 126. It is a two-position solenoid valve that shuts off the connecting path.

SFRR112, SFLR114, SRR
A return passage 20 communicates with R116 and SRLR118. The SFRR 112 is a two-position solenoid valve that is turned off to disconnect the wheel cylinder 120 from the return passage 20 and turned on to bring the wheel cylinder 120 and the return passage 20 into conduction. Is. Similarly, SFLR114, S
The RRR 116 and the SRLR 118 are turned on to respectively connect the wheel cylinder 122 and the return passage 20, the path connecting the wheel cylinder 124 and the return passage 20, and the wheel cylinder 12.
This is a two-position solenoid valve that connects the path connecting 6 and the return passage 20 to each other.

A wheel speed sensor 13 is provided near the right front wheel FR.
6 are provided. The wheel speed sensor 136 is the right front wheel F.
A pulse signal is output at a cycle corresponding to the rotation speed of R. Similarly, in the vicinity of the left front wheel FL, in the vicinity of the right rear wheel RR, and
Near the left rear wheel RL, a wheel speed sensor 1 that outputs a pulse signal at a cycle corresponding to the rotation speed of the corresponding wheel.
38, 140, 142 are arranged. Output signals of the wheel speed sensors 136 to 142 are supplied to the ECU 10. ECU10 detects the rotational speed V _W of each wheel based on the output signal of the wheel speed sensors 136-142.

A hydraulic pressure sensor 144 is provided in the second hydraulic pressure passage 84 communicating with the second hydraulic chamber 58 of the hydrobooster 36. The hydraulic pressure sensor 144 controls the hydraulic pressure generated inside the second hydraulic chamber 58, that is, the hydro booster 36.
An electric signal corresponding to the master cylinder pressure P _{M / C} generated by is output. The output signal of the fluid pressure sensor 144 is EC
Supplied to U10. The ECU 10 uses the hydraulic pressure sensor 1
The master cylinder pressure P _{M / C} is detected based on the output signal of 44.

Next, the operation of the braking force control system of this embodiment will be described. The braking force control device of the present embodiment switches the states of various electromagnetic valves arranged in the hydraulic circuit to function as a normal braking device, a function as an antilock braking system, and a braking force. A function (brake assist function) for generating a larger braking force than in a normal case when a quick start is required is realized.

FIG. 1 shows a state of a braking force control device for realizing a function as a normal brake device (hereinafter referred to as a normal brake function). That is, the normal braking function is realized by turning off all the electromagnetic valves included in the braking force control device, as shown in FIG. Hereinafter, the state shown in FIG. 1 is referred to as a normal braking state. Also,
The control for realizing the normal braking function in the braking force control device is called normal braking control.

In FIG. 1, the wheel cylinders 120 and 122 of the left and right front wheels FL and FR communicate with the first hydraulic chamber 56 of the hydrobooster 34 via the first hydraulic pressure passage 82. In addition, the wheel cylinders 12 for the left and right rear wheels RL, RR
4, 126 communicate with the second hydraulic chamber 58 of the hydro booster 36 via the second hydraulic pressure passage 84. in this case,
Wheel cylinder pressure P of wheel cylinders 120-126
_{W / C} is always controlled to be equal to the master cylinder pressure P _{M / C.} Therefore, according to the state shown in FIG. 1, the normal braking function is realized.

FIG. 3 shows the state of the braking force control device for realizing the function as an antilock brake system (hereinafter referred to as ABS function). That is, ABS
As shown in FIG. 3, the functions are SA _-1 86 and SA _-2 88.
Is turned on and the holding solenoid S ** H and the pressure reducing solenoid S ** R are appropriately driven in response to the ABS request. Hereinafter, the state shown in FIG. 3 is referred to as an ABS operating state. Further, the control for realizing the ABS function in the braking force control device is referred to as ABS control.

The ECU 10 starts the ABS control when the vehicle is in a braking state and an excessive slip ratio is detected for any of the wheels. During the ABS control, the hydraulic pressure passages 96 and 98 provided corresponding to the front wheels communicate with the second hydraulic chamber 58 of the hydro booster 36, similarly to the hydraulic passages 100 provided corresponding to the rear wheels. Therefore, ABS
During control, the wheel cylinder pressures P _{W / C of} all wheels become the second
The pressure is increased by using the hydraulic chamber 58 as a hydraulic pressure source.

During execution of the ABS control, the holding solenoid S
* H is opened, and pressure reducing solenoid S ** R
Is closed, the wheel cylinder pressure P _{W / C of} each wheel is
Can be increased. Hereinafter, this state is referred to as (i) pressure increasing mode. Also, hold solenoid S * during ABS control.
When both * H and the pressure reducing solenoid S ** R are closed, the wheel cylinder pressure P _{W / C} of each wheel can be maintained. Hereinafter, this state is referred to as (ii) holding mode.
Further, when the holding solenoid S ** H is closed and the pressure reducing solenoid S ** R is opened during the ABS control, the wheel cylinder pressure P _{W / C} of each wheel can be reduced. Hereinafter, this state is referred to as (iii) decompression mode.

During the ABS control, the ECU 10 appropriately realizes the above-mentioned (i) pressure increasing mode, (ii) holding mode, and (iii) pressure reducing mode according to the slip state of each wheel. Control the holding solenoid S ** H and the pressure reducing solenoid S ** R. Holding solenoid S **
When the H and the pressure reducing solenoid S ** R are controlled as described above, the wheel cylinder pressure P _{W / C} of all the wheels is controlled to a pressure that does not cause an excessive slip ratio in the corresponding wheels. Therefore, according to the above control, the ABS function can be realized in the braking force control device.

During the ABS control, the brake fluid in the wheel cylinders 120 to 126 is discharged to the return passage 20 every time the pressure reducing mode is performed on each wheel. Then, every time the pressure increasing mode is performed on each wheel, the hydro booster 36
Brake fluid is supplied from the wheel cylinders 120 to 126. Therefore, during the ABS control, a larger amount of brake fluid flows out from the hydro booster 36 than during normal braking.

A hydraulic pressure source such as the accumulator 28 does not communicate with the first hydraulic chamber 56 of the hi-rod booster 36. Therefore, if the first hydraulic chamber 56 is used as a hydraulic pressure source during execution of the ABS control, a large amount of brake fluid in the first hydraulic chamber 56 flows out, and as a result, an excessive stroke is applied to the brake pedal 12. A situation occurs. On the other hand, in the system of the present embodiment, the second hydraulic chamber 58 that communicates with the accumulator 28 via the spool portion 54 is used as a hydraulic pressure source during ABS control. Therefore, according to the system of this embodiment, the brake pedal 12 does not have an excessive stroke during the execution of the ABS control.

4 to 6 show the states of the braking force control device for realizing the brake assist function (hereinafter referred to as BA function). 4 to 6 after the ECU 10 executes a braking operation that requires a quick rise of the braking force by the driver, that is, an emergency braking operation.
The BA function is realized by appropriately realizing the state shown in.
Hereinafter, in the braking force control device, control for realizing the BA function is referred to as BA control.

FIG. 4 shows the assist pressure increasing state realized during execution of the BA control. The assist pressure increase state is BA
It is realized when it is necessary to increase the wheel cylinder pressure P _{W / C} of each wheel during execution of the control. In the system of the present embodiment, the assist pressure increasing state is as shown in FIG.
SA _-1 86, SA _-2 88, SA _-3 90 and STR 94
It is realized by turning on.

In the assist pressure increasing state, all the wheel cylinders 120 to 126 communicate with the accumulator passage 26 via the STR 94. Therefore, when the assist pressure increasing state is realized, the wheel cylinder pressure P of all wheels is increased.
_{W / C} can be boosted by using the accumulator 28 as a hydraulic pressure source. A high-pressure accumulator pressure P _ACC is stored in the accumulator 28. Therefore, according to the assist pressure increasing state, the wheel cylinder pressure P of all wheels is increased.
_{W / C} can be increased to a higher pressure than the master cylinder pressure P _{M / C.}

By the way, in the assist pressure increasing state shown in FIG. 4, the hydraulic pressure passages 96, 98, 100 communicate with the accumulator passage 26 as described above, and the second hydraulic pressure is passed through the check valve 102. It communicates with the passage 84. Therefore, the master cylinder pressure P introduced to the second hydraulic pressure passage 84 is
If _{M / C} is greater than the wheel cylinder pressure P _{W / C} of each wheel can boost the wheel cylinder pressure P _{W / C} of the hydro-booster 36 even in the assist pressure increasing state as a fluid pressure source .

FIG. 5 shows the assist pressure holding state realized during execution of the BA control. The assist pressure holding state is BA
It is realized when it is necessary to maintain the wheel cylinder pressure P _{W / C} of each wheel during execution of the control. As shown in FIG. 5, the assist pressure holding state is SA _-1 86, SA _-2 88, SA _-3.
With 90 and STR94 turned on,
All holding solenoids S ** H are on (valve closed)
It is realized by

In the assist pressure holding state, the hydro booster 36 and the wheel cylinders 120 to 126 are cut off, and the return passage 20 and the wheel cylinders 120 to 12 are cut off.
6 is cut off, and the flow of fluid from the accumulator 28 toward the wheel cylinders 120 to 126 is blocked. Therefore, according to the assist pressure holding state, the wheel cylinder pressures P _{W / C} of all the wheels can be held at a constant value.

FIG. 6 shows the assist pressure reducing state realized during execution of the BA control. The assist pressure reduction state is BA
It is realized when it is necessary to reduce the wheel cylinder pressure P _{W / C} of each wheel during execution of the control. The assist pressure reduction state is realized by turning on SA _-1 86 and SA _-2 88, as shown in FIG. In the assist pressure reducing state, the accumulator 28 and the wheel cylinders 120 to 12
6 is shut off, the return passage 20 and the wheel cylinders 120 to 126 are shut off, and the hydrobooster 36 and the wheel cylinders 120 to 126 are brought into conduction. Therefore, according to the assist pressure reducing state, the wheel cylinder pressure P _{W / C} of all the wheels can be reduced with the master cylinder pressure P _{M / C} as the lower limit value.

FIG. 7 shows an example of a time chart realized when the driver performs an emergency braking operation in the braking force control system of this embodiment. FIG. 7 (A)
The curve indicated by is the master cylinder pressure P _{M / C} per unit time when the driver performs an emergency braking operation.
An example of a change that occurs in the change amount ΔP _{M / C} (hereinafter, referred to as a change speed ΔP _{M / C} ) is shown. Further, in FIG. 7 (B), the curve shown by the broken line and the curve shown by the solid line show an example of changes that occur in the master cylinder pressure P _{M / C} and the wheel cylinder pressure P _{W / C} , respectively, under similar conditions. In the system of the present embodiment, the master cylinder pressure P _{M / C} and its changing speed ΔP _{M / C} are characteristic values of the operation amount of the brake pedal 12 and the operation speed of the brake pedal 12, respectively.

When an emergency braking operation is performed by the driver, the master cylinder pressure P _{M / C} is quickly increased to an appropriate pressure after the braking operation is started, as indicated by a broken line in FIG. 7 (B). It At this time, the master cylinder pressure P
_As shown in FIG. 7 (A), the change speed ΔP _{M / C} of _{M / C} tends toward the maximum value ΔP _MAX in synchronization with the time when the master cylinder pressure P _{M / C} rapidly increases after the brake operation is started. It also increases and decreases to a value near "0" in synchronization with the time when the master cylinder pressure P _{M / C} converges to an appropriate pressure.

As described above, the ECU 10 executes BA control when an emergency braking operation by the driver is detected. When determining whether or not an emergency braking operation has been performed by the driver, the ECU 10 first operates the brake pedal 12 that exceeds a predetermined speed, specifically, a change speed ΔP _M that exceeds the first predetermined speed THΔP1. _{/ C} is detected. When the ECU 10 detects the changing speed ΔP _{M / C} that satisfies ΔP _{M / C} > THΔP1, the ECU 10 determines that the emergency braking operation may have been performed, and shifts to the first standby state (FIG. 7 (B)). Medium period). Here, the above
The “1 standby state” is the “standby state” according to claim 1.
State ”.

After the shift to the first standby state, the ECU 10 takes time t2 until the change speed ΔP _{M / C} of the master cylinder pressure P _{M / C} becomes equal to or lower than the second predetermined speed THΔP2.
Count t1 = CSTANBY1. And ECU1
When the elapsed time CSTANBY1 is within the predetermined range, 0 determines that the driver has performed the emergency braking operation and shifts to the second standby state (intermediate period in FIG. 7B). Here, the above "elapsed time CSTANBY1 is
When it is within the predetermined range ", the" main braking force "according to claim 1.
The controller is in the standby state and the emergency
Emergency braking operation detected by the braking operation detection means
It is an example of the case of "was done".

In the braking force control apparatus of this embodiment, while the master cylinder pressure P _{M / C} is rapidly increased, it is between the master cylinder pressure P _{M / C} and the wheel cylinder pressure P _{W / C.} A large deviation Pdiff occurs. Under such circumstances, the wheel cylinder pressure P _{W / C} can be raised more quickly when the hydro booster 36 is used as the hydraulic pressure source than when the accumulator 28 is used as the hydraulic pressure source.

Therefore, after the emergency braking operation is performed by the driver, until the deviation Pdiff becomes a sufficiently small value, maintaining the normal brake control is faster than starting the BA control. The cylinder pressure P _{W / C} can be raised. Therefore, the ECU 10 starts the BA control when the deviation Pdiff becomes a sufficiently small value after shifting to the second standby state described above. When the BA control is started at such a timing, the wheel cylinder pressure P _{W / C} can be efficiently and promptly increased after the emergency braking operation is started.

In the braking force control system of this embodiment, BA
When the control is started, first, the (I) start pressure increasing mode is executed (the middle period in FIG. 7B). (I) Start boosting mode
This is realized by maintaining the assist pressure increasing state shown in FIG. 4 for a predetermined pressure increasing time T _STA . As described above, according to the assist pressure increasing state, the wheel cylinder pressure P _{W / C of} each wheel is increased to a pressure exceeding the master cylinder pressure P _{M / C} using the accumulator 28 as a hydraulic pressure source. Therefore, when the BA control is started, (I) the wheel cylinder pressure P _{W / C of} each wheel is quickly increased to a pressure exceeding the master cylinder pressure P _{M / C} with the execution of the start pressure increasing mode. .
Hereinafter, the differential pressure generated between the wheel cylinder pressure P _{W / C} and the master cylinder pressure P _{M / C} during execution of the BA control is referred to as an assist pressure Pa.

In the present embodiment, the pressure increase time T _STA is calculated based on the maximum value ΔP _MAX of the changing speed ΔP _{M / C} that has occurred in the master cylinder pressure P _{M / C} during the emergency braking operation. Specifically, the pressure increase time T _STA is the change rate ΔP.
_The larger the maximum _{M / C} value ΔP _{MAX, the} longer the time will be set.
Further, the smaller the maximum value ΔP _MAX is, the shorter the time is set.

The maximum value ΔP _MAX of the changing speed ΔP _{M / C} becomes so large that the driver intends to quickly raise the braking force. Therefore, when the maximum value ΔP _MAX is a large value, it is appropriate to increase the wheel cylinder pressure P _{W / C} largely after the BA control is started as compared with the master cylinder pressure P _{M / C.} . Boosting time T _STA is the maximum value Δ
When set as described above based on P _MAX , the wheel cylinder pressure P _{W / C is set} to the master cylinder pressure P _M after the emergency braking operation is detected so that the driver intends to quickly raise the braking force. Greatly increase pressure compared to _{/ C} ,
That is, a large assist pressure Pa can be generated. Therefore, according to the braking force control device of this embodiment,
(I) After the execution of the start pressure increasing mode is started, the wheel cylinder pressure P _{W / C in} which the driver's intention is accurately reflected can be promptly generated.

In the braking force control system of this embodiment, (I)
When the start pressure increasing mode ends, thereafter, in response to the driver's brake operation, (II) assist pressure increasing mode, (III) assist pressure reducing mode, (IV) assist pressure holding mode, (V)
Either the assist pressure moderate increase mode or the (VI) assist pressure moderate decrease mode is executed. If the master cylinder pressure P _{M / C} is rapidly increased during the execution of the BA control, it can be determined that the driver is requesting a larger braking force.
In this case, the braking force control system of this embodiment executes the (II) assist pressure increasing mode (intermediate period in FIG. 7B).
The (II) assist pressure increasing mode is realized by setting the braking force control device to the assist pressure increasing state, as in the (I) start pressure increasing mode described above. According to the assist pressure increase state,
Wheel cylinder pressure P _{W / C} of each wheel is accumulator pressure P
It is possible to quickly boost the voltage toward _ACC . Therefore, according to the above process, the driver's intention can be accurately reflected in the wheel cylinder pressure P _{W / C.}

During execution of the BA control, the master cylinder pressure P
_{If the M / C} is suddenly decompressed, it can be determined that the driver intends to quickly reduce the braking force.
In this embodiment, in this case, the (III) assist pressure reducing mode is executed (intermediate period in FIG. 7B). The (III) assist pressure reducing mode is realized by maintaining the assist pressure reducing state shown in FIG. According to the assist pressure reduction state, as described above, the wheel cylinder pressure P _{W / C of} each wheel is
Can be quickly reduced toward the master cylinder pressure P _{M / C.} Therefore, according to the above process, the driver's intention can be accurately reflected in the wheel cylinder pressure P _{W / C.}

Master cylinder pressure P during execution of BA control
_{If the M / C} is maintained at a substantially constant value, it can be determined that the driver intends to maintain the braking force. In the present embodiment, in this case, the (IV) assist pressure holding mode is executed (in the middle period of FIG. 7B). (IV) The assist pressure holding mode is realized by maintaining the assist pressure holding state shown in FIG. According to the assist pressure holding state, as described above, the wheel cylinder pressure P _{W / C of} each wheel is
Can be maintained at a constant value. Therefore, according to the above processing, the wheel cylinder pressure P
Can be reflected in _{W / C.}

Master cylinder pressure P during execution of BA control
_{When the M / C} is gradually increased in pressure, it can be determined that the driver intends to gradually increase the braking force. In the present embodiment, in this case, the (V) assist pressure gentle increase mode (not shown) is executed. The (V) assist pressure moderate increase mode is realized by repeating the assist pressure increase state shown in FIG. 4 and the assist pressure holding state shown in FIG. According to the (V) assist pressure gentle increase mode, the wheel cylinder pressure P _{W / C} of each wheel can be gradually increased toward the accumulator pressure P _ACC . Therefore, according to the above processing, the wheel cylinder pressure P
Can be reflected in _{W / C.}

Master cylinder pressure P during execution of BA control
_{When the M / C} is gently decompressed, it can be determined that the driver intends to gently reduce the braking force. In this embodiment, in this case, the (VI) assist pressure gradual decrease mode is executed (intermediate period in FIG. 7B). (VI) The assist pressure gradual decrease mode is realized by repeating the assist pressure reducing state shown in FIG. 6 and the assist pressure holding state shown in FIG. (VI) According to the assist pressure moderation mode, the wheel cylinder pressure P _{W / C} of each wheel is set to the master cylinder pressure P
_The pressure can be gradually reduced toward the _{M / C.} Therefore, according to the above process, the driver's intention can be accurately reflected in the wheel cylinder pressure P _{W / C.}

According to the above process, the assist pressure Pa accurately reflecting the driver's intention can be generated immediately after the driver performs the emergency braking operation. Therefore, according to the braking force control device of the present embodiment,
The rising tendency of the braking force can be changed according to the driver's intention. Further, according to the above processing, (I) after the assist pressure Pa is generated in the start pressure increasing mode,
When the driver performs a brake operation, the wheel cylinder pressure P _{W / C} can be increased or decreased corresponding to the brake operation. Therefore, according to the above processing, B
It is possible to appropriately reflect the driver's intention in the wheel cylinder pressure P _{W / C} while maintaining the assist pressure Pa at a substantially constant value during execution of the A control.

When the BA control is started in the braking force control device, the wheel cylinder pressure P _{W / C of} each wheel is rapidly increased thereafter, which may cause an excessive slip ratio in any of the wheels. is there. In such a case, the ECU 10 executes ABS control in addition to BA control. Hereinafter, this control is referred to as BA + ABS control. BA
The + ABS control realizes one of the states shown in FIG. 4 to FIG.
For the ABS target wheel), the holding solenoid S ** H and the pressure reducing solenoid S ** are appropriately provided so as to realize the above-mentioned (i) pressure increasing mode, (ii) holding mode, and (iii) pressure reducing mode. It is realized by controlling R.

That is, when the assist pressure increasing state shown in FIG. 4 or the assist pressure holding state shown in FIG. 5 is realized, the accumulator pressure P _ACC is supplied to all the holding solenoids S ** H. To be done. Under these circumstances, by appropriately controlling the holding solenoid S ** H and the pressure reducing solenoid S ** R, (ii) the holding mode, (iii) the pressure reducing mode, and the wheel cylinder pressure for all wheels. It is possible to realize (i) a pressure increasing mode for the purpose of increasing P _{W / C} to a pressure exceeding the master cylinder pressure P _{M / C.} Therefore, when either of the states shown in FIGS. 4 and 5 is realized, the BA + ABS control is performed by controlling the holding solenoid S ** H and the pressure reducing solenoid S ** R in response to the ABS control request. Can be realized.

Further, when the assist pressure reducing state shown in FIG. 6 is realized, the master cylinder pressure P _{M / C} is supplied to all the holding solenoids S ** H. In this case, (ii) the holding mode and (iii) the pressure reducing mode can be realized for all the wheels. By the way, FIG.
The assist pressure reduction state indicated by is realized when the driver intends to reduce the braking force, that is, when it is not necessary to increase the wheel cylinder pressure P _{W / C of} any wheel. Therefore, if the (ii) holding mode and (iii) pressure reducing mode can be achieved for the ABS target wheel when the assist pressure reducing state shown in FIG.
The requirement of A + ABS control can be satisfied.

As described above, according to the braking force control apparatus of the present embodiment, after the BA control is started, one of the states shown in FIGS. Holding solenoid S ** H and pressure reducing solenoid S *
By controlling * R, BA + ABS control can be realized. According to the above BA + ABS control,
By using the accumulator 28 as a hydraulic pressure source, it is possible to control the wheel cylinder pressure P _{W / C} of all the wheels to an appropriate pressure that does not generate an excessive slip ratio on the corresponding wheels.

Next, the contents of the processing executed by the ECU 10 to realize the above-mentioned BA control will be described with reference to FIGS. 8 to 24. FIG. 8 shows a flowchart of an example of a control routine executed by the ECU 10 to perform the condition determination for shifting to the first standby state and the condition determination for maintaining the first standby state. The routine shown in FIG. 8 is a timed interrupt routine that is activated every predetermined time. When the routine shown in FIG. 8 is started,
First, the process of step 200 is executed.

In step 200, the flag XSTANB is set.
It is determined whether Y1 is in the on state. XSTAN
BY1 is a flag that is turned on when the condition for shifting to the first standby state is satisfied. Therefore, when the condition for shifting to the first standby state is not satisfied, it is determined that XSTANBY1 = ON is not satisfied. In this case, the process of step 202 is executed next.

In step 202, the first predetermined amount THP1 and the first predetermined speed THΔP are set according to the driving state of the vehicle.
1 and the noise cut value THNC are set. The first predetermined amount THP1, the first predetermined speed THΔP1, and the noise cut value THNC are threshold values used to determine the transition condition to the first standby state. That is, in the present embodiment, the transition condition to the first standby state is that the master cylinder pressure P _{M / C} is set, as described later.
And the rate of change ΔP _{M / C} thereof are satisfied when both conditions of P _{M / C} ≧ THP1 and THΔP1 <ΔP _{M / C} <THNC are satisfied.

In step 202, THP1,
THΔP1 and THNC are the vehicle speed SPD and the elapsed time T after the brake switch 14 is turned on.
Based on _STOP , it is set as shown in Table 1 below.

[0083]

[Table 1]

The first predetermined amount THP1 is shown in Table 1 above.
Thus, the vehicle speed SPD is the predetermined speed V₀Predetermined if above
The amount is set to THP1L. Also, the vehicle speed SPD is a predetermined speed
Degree V ₀If it is less than, it is set to a predetermined amount THP1H
It For THP1L and THP1H, THP1L <TH
It is set so that the relationship of P1H is established. First
When the predetermined amount THP1 is set to the value shown in Table 1 above, the
P, which is one of the conditions for transition to the standby state_{M / C}≧ T
HP1 is easily established when traveling at high speed, and when traveling at low speed.
It will be difficult to establish.

[0085] When the vehicle is running at a low speed is different from when the vehicle is in high speed, poor need to launch braking force promptly. Further, during low-speed traveling, deceleration acceleration is more likely to be felt during braking than during high-speed traveling. Therefore, when the vehicle is traveling at a low speed, it is appropriate that the BA control is less likely to be started than when the vehicle is traveling at a high speed.
By setting the first predetermined amount THP1 to the value shown in Table 1 above, such a request can be realized.

The first predetermined speed THΔP1 is shown in Table 1 above.
As shown, the vehicle speed SPD is the predetermined speed V ₀Or more
After the brake switch 14 is turned on
Time T _STOPIs the predetermined time T₀If not reached the specified speed
The degree THΔP1H is set. Also, the vehicle speed SPD is predetermined
Speed V₀If less than, set to a predetermined speed THΔP1M
To be done. THΔP1H and THΔP1M are THΔP
1H <THΔP1M
There is. The first predetermined speed THΔP1 is set as described above.
Then, one of the transition conditions to the first standby state is T
HΔP1 ≦ P_{M / C}Is easily established when traveling at high speed, and
It becomes difficult to establish it at low speed.

At low speeds, since the longitudinal acceleration G generated in the vehicle fluctuates greatly, the BA control is executed,
It is easy for a vehicle occupant to feel a large deceleration G. When the first predetermined speed THΔP1M is set as described above and it is difficult to satisfy the condition for shifting to the standby state at the time of low speed, the BA control is executed, so that the occupant may feel a large deceleration G unnecessarily. Can be prevented.

The first predetermined speed THΔP1 is, as shown in Table 1 above, the vehicle speed SPD is a predetermined speed V ₀ or more and the elapsed time T _STOP after the brake switch 14 is turned on is predetermined. When it is the time T ₀ or more, that is, when the time T ₀ has elapsed after the brake operation is started, the predetermined speed THΔP1L is set. T
HΔP1L is a smaller value than THΔP1M. When the first predetermined speed THΔP1 is set as described above, TH which is one of the transition conditions to the first standby state is set.
ΔP1 ≦ P _{M / C} is more likely to be established after T _STOP ≧ T ₀ is established than it is before.

In a vehicle, an emergency brake operation may be started when a certain amount of time has passed after the brake operation was started. In this case, since the brake pedal 12 is already depressed at the time when the emergency braking operation is started, it is difficult for the change speed ΔP _{M / C} that occurs after the emergency braking operation is started to become high. Therefore, in order to accurately detect such an emergency braking operation,
After a certain amount of time has elapsed from the start of the brake operation, the first predetermined speed THΔP1 which is the threshold value for determining the presence / absence of the emergency brake operation may be set to a value smaller than the previous value. Appropriate. First predetermined speed TH
By setting ΔP1 to the value shown in Table 1 above, such a request can be realized.

The noise cut value THNC is shown in Table 1 above.
As described above, the vehicle speed SPD is the predetermined speed V₀And above, and
Elapsed time T after the brake operation is started_STOPWhen
Interval T ₀If the value has not reached, the specified value THNCH is set.
Be done. Further, the vehicle speed SPD is the predetermined speed V₀Or more
One, elapsed time T_STOPIs the predetermined time T₀If it is more than
And the vehicle speed SPD is the predetermined speed V₀If less than the prescribed
The speed is set to THNCL. THNCH and THN
As for CL, the relation of THNCH> THNCL is established.
Is set to.

SPD ≧ V ₀ holds and T _STOP ≧ T
_{When 0} is not established, as described above, a large change speed ΔP _{M / C} is generated with the emergency braking operation. Therefore,
In this case, it is appropriate to treat the relatively large change rate ΔP _{M / C} as valid data. On the other hand, when both SPD ≧ V ₀ and T _STOP ≧ T ₀ are satisfied, and SP
When D <V ₀ is established, as described above, it is difficult for the change speed ΔP _{M / C to} have a large value due to the emergency braking operation.
Therefore, in this case, it is appropriate to treat the relatively large change rate ΔP _{M / C} as an abnormal value. Noise cut value T
By setting the HNC to the values shown in Table 1 above, such a request can be realized.

According to the above method, the first predetermined amount THP
When 1, the first predetermined speed THΔP1 and the noise cut value THNC are set, the process of step 204 is then executed. In step 204, it is judged if the master cylinder pressure P _{M / C} is equal to or higher than the first predetermined amount THP1. As a result, when it is determined that P _{M / C} ≧ THP1 is not established, it is determined that the condition for transitioning to the first standby state is not established, and this routine is ended. On the other hand, if it is determined that P _{M / C} ≧ THP1 is established, then the process of step 206 is executed.

At step 206, the changing speed ΔP
_It is determined whether _{M / C} is larger than the first predetermined speed THΔP1 and smaller than the noise cut value THNC. As a result, THΔP1 <ΔP _{M / C} <THNC
If it is determined that the condition is not satisfied, it is determined that the condition for shifting to the first standby state is not satisfied, and the routine of this time is ended. On the other hand, if it is determined that the above conditions are met, then the process of step 208 is executed.

At step 208, the flag XST is set to indicate that the condition for shifting to the first standby state is satisfied.
ANBY1 is turned on. When the process of step 208 is finished, the routine of this time is finished. When the routine is started after the flag XSTANBY1 is turned on in step 208, it is determined in step 200 that XSTANBY1 = ON. In this case, step 200 is followed by step 2
Ten processes are executed.

In step 210, the counter CSTAN
The process of incrementing BY1 is executed. The counter CSTANBY1 is a counter for counting the elapsed time after the condition for shifting to the first standby state is satisfied. The counting time of the counter CSTANBY1 is reset to "0" by the initial process when the vehicle is started. When the process of step 210 is completed, the process of step 212 is executed next.

In step 212, the counter CSTAN
It is determined whether or not the time counted in BY1 is the predetermined time α or less. The predetermined time α is a smaller value than the time during which the changing speed ΔP _{M / C} is maintained at a large value when the emergency braking operation is performed. As a result of the above determination, C
If it is determined that STANBY1 ≦ α is established, then the process of step 214 is executed.

At step 214, it is judged if the rate of change ΔP _{M / C} is below a predetermined value β. As a result, when ΔP _{M / C} <β is established, it can be determined that the change speed ΔP _{M / C} has become a small value after an extremely short period of time after the transition condition to the first standby state is established. it can. In this case, it is determined that the driver's braking operation was not an emergency braking operation, and then the process of step 216 is executed.

At step 216, the processing for turning off the flag XSTANBY1 is executed to cancel the first standby state. When the process of step 216 is executed, the process of step 218 is then executed. In step 218, a process of resetting the counting time of the counter CSTANBY1 to "0" is executed. This step 2
When the process of 18 ends, the routine of this time is ended.

In this routine, the above step 212 is executed.
If it is determined that CSTANBY1 ≦ α is not satisfied in step S1 and if it is determined that ΔP _{M / C} <β is not satisfied in step S214, it is extremely short after the condition for shifting to the first standby state is satisfied. Change rate ΔP during time
It can be judged that the phenomenon that the _{M / C} drops to a small value has not occurred. In this case, the process of step 220 is executed next.

In step 220, the counter CSTAN
It is determined whether or not the count value of BY1 is equal to or greater than the second predetermined time THT2. The second predetermined time THT2 is a value that defines the upper limit value of the time for which the first standby state is maintained after the condition for shifting to the first standby state is satisfied. Therefore, in this step 220, CSTANBY1 ≧ THT2
When it is determined that the above condition holds, it can be determined that the duration of the first standby state has reached the upper limit. In this case, next, after the processes of steps 216 and 218 are executed, the routine of this time is ended. On the other hand, if it is determined in this step 220 that CSTANBY1 ≧ TH2 is not established, it can be determined that the duration of the first standby state has not reached the upper limit yet.
In this case, the process of step 222 is next performed.

At step 222, the flag XSTANB is set.
It is determined whether Y2 is in the on state. Flag XS
TANBY2 is the second routine in another routine described later.
It is a flag that is turned on when it is determined that the condition for shifting to the standby state is satisfied. XSTANBY2
When it is determined that = ON is established, it is determined that it is not necessary to maintain the first standby state. In this case, next, after the processes of steps 216 and 218 are executed, the routine of this time is ended. On the other hand, XSTAN
When it is determined that BY2 = ON is not established, it is determined that the first standby state needs to be maintained. In this case, the current routine is terminated without any further processing.

FIG. 9 shows a flowchart of an example of a control routine executed by the ECU 10 to make a condition determination for shifting to the second standby state. The routine shown in FIG. 9 is a scheduled interrupt routine that is activated every predetermined time. When the routine shown in FIG. 9 is started, the process of step 230 is first executed. In step 230, the counting time of the counter CSTANBY1, that is, the first
It is determined whether or not the elapsed time after the condition for shifting to the standby state is satisfied is equal to or greater than the first predetermined time THT1 and equal to or less than the second predetermined time THT2. Second
The predetermined time THT2 is the upper limit value of the time during which the first standby state should be maintained, as described above. On the other hand, during the first predetermined time THT1, when the emergency braking operation is performed,
It is a value that defines a lower limit time during which high-speed operation of the brake pedal 12 continues.

Therefore, in the braking force control system of this embodiment, after the brake operation is started, THT1≤CST.
If the operation speed of the brake pedal 12 becomes a sufficiently small value before ANBY1 is established, it can be determined that the braking operation is not the emergency braking operation. In the above step 230, THT1 ≦ CSTANB
When it is determined that Y1 ≦ THT2 is not established, the routine of this time is ended without any further processing thereafter. On the other hand, if it is determined that the above conditions are met, then the process of step 232 is executed.

At step 232, the change speed ΔP is changed from the previous processing cycle to the current processing cycle.
_It is determined whether or not the _{M / C} has changed from a speed exceeding the second predetermined speed THΔP2 to a speed equal to or lower than the second predetermined speed THΔP2. The second predetermined speed THΔP2 is determined by whether or not the master cylinder pressure P _{M / C} is rapidly increasing, that is,
This is a threshold value for determining whether or not the brake pedal 12 is being operated at high speed.

In step 232, the change speed ΔP is changed from the previous processing cycle to the current processing cycle.
_{When it} is determined that the _{M / C} has not changed from the speed exceeding THΔP2 to the speed equal to or lower than THΔP2, it means that the high-speed operation period of the brake pedal 12 has not ended from the time of the last processing cycle to the time of this processing cycle. You can judge. In this case, the current routine is terminated without any further processing.

On the other hand, if it is determined in step 232 that the change speed ΔP _{M / C} has changed from the speed exceeding THΔP2 to the speed equal to or lower than THΔP2 from the time of the previous processing cycle to the time of this processing cycle, It is possible to determine that the high-speed operation period of the brake pedal 12 has ended from the processing cycle of 1 to the processing cycle of this time. In this case, the process of step 234 is then executed.

At step 234, the maximum value P _{M / CMAX of} the master cylinder pressure P _{M / C} detected after the condition for shifting to the first standby state is satisfied, and the master cylinder immediately after the condition at step 232 is satisfied. Difference from pressure P _{M / C} "P
_It is determined whether or not _{M / CMAX-} P _{M / C} "is smaller than the predetermined value γ. As a result, if it is determined that P _{M / CMAX-} P _{M / C} <γ is established, it is still _unsolved . It can be determined that a large pedaling force F is applied to the brake pedal 12. In this case, the process of step 236 is executed next. Can determine that the depression of the brake pedal 12 has already been loosened.In this case, the routine for this time is ended without proceeding the process for shifting to the second standby state.

In step 236, the flag XST is set to indicate that the condition for transitioning to the second standby state is satisfied.
ANBY2 is turned on. When the processing of this step 236 ends, the routine of this time is ended. Figure 10
Is to determine the condition for starting the BA control and to calculate the pressure increasing time T _{SAT in} the start pressure increasing mode.
10 shows a flowchart of an example of a control routine executed by 0. The routine shown in FIG. 10 is a timed interrupt routine that is activated every predetermined time. When the routine shown in FIG. 10 is started, the process of step 240 is first executed.

At step 240, the flag XSTANB is set.
It is determined whether Y2 is in the on state. as a result,
When it is determined that XSTANBY2 = ON is not established, it can be determined that it is not necessary to start the BA control. In this case, the current routine is terminated without any further processing. On the other hand, XSTANBY2
If it is determined that = ON is established, then step 2 is performed.
The process of 42 is performed.

In step 242, the reference pressure increase time T _STA0 which is the reference value of the pressure increase time T _STA is calculated. The reference pressure increase time T _STA0 refers to a map stored in the ECU 10, and based on the operation speed of the brake pedal 12 generated in the process of emergency braking, specifically, shifts to the first standby state. It is determined based on the maximum value ΔP _MAX of the changing speed ΔP _{M / C} detected after the condition is satisfied.

FIG. 11 shows an example of the map referred to in step 242. In the present embodiment, the map of the reference pressure increase between T _STA0 is between the maximum change rate [Delta] P _MAX is too large reference pressure increase T _STA0 is set to be long. For this reason, the reference pressure increase time T _STA0 is set to a long time so that a high speed operation of the brake pedal 12 occurs during the emergency braking operation. When the above process ends, the process of step 244 is next executed.

At step 244, it is judged if the BA control start timing has come. As described above, in this embodiment, when the wheel cylinder pressure P _{W / C} is increased after the emergency braking operation is performed, the hydro booster 36 is used as the hydraulic pressure source when the accumulator 28 is used as the hydraulic pressure source. The BA control is started when a more advantageous state is formed, that is, when the deviation Pdiff between the master cylinder pressure P _{M / C} and the wheel cylinder pressure P _{W / C} becomes sufficiently small. In step 244, it is determined whether or not the start timing has arrived. As a result, if it is determined that the BA control start timing has not come, then the routine of this time is ended without any further processing. On the other hand, if it is determined that the BA control start timing has arrived, then the process of step 246 is executed.

At step 246, the master cylinder pressure P
_It is determined whether _{M / C} is larger than the predetermined pressure P ₀ . After the BA control is started, the wheel cylinder pressure P _{W / C}
Is boosted using the accumulator 28 as a hydraulic pressure source. Wheel cylinder pressure P using accumulator 28 as a hydraulic pressure source
_The rate of change ΔP _{W / C} that occurs when _{W / C} is increased decreases as the differential pressure between the wheel cylinder pressure P _{W / C} and the accumulator pressure P _ACC decreases. Therefore, in order to generate the predetermined assist pressure Pa by executing the start pressure increasing mode after the BA control is started, the higher the wheel cylinder pressure P _{W / C} at the start of the BA control is, It is necessary to lengthen the pressure increasing time T _STA .

When it is determined in step 246 that P _{M / C} > P ₀ is established, it can be determined that the high wheel cylinder pressure P _{W / C} is generated at the start of the BA control.
In this case, since the pressure increase time T _{STA is set} to be long, the process of step 248 is executed next. On the other hand, P _{M / C} > P ₀
If it is determined that is not established, it can be determined that the wheel cylinder pressure P _{W / C} at the start of the BA control is low. In this case, the pressure increase time T _{STA is set} to a short time, so that the process of step 250 is performed next.

In step 248, the above step 242 is executed.
The pressure increase time T _STA is calculated by multiplying the reference pressure increase time T _STA0 calculated in step 1 by the correction count K _L. The correction coefficient K _L is a correction coefficient preset to set a long pressure increasing time T _STA . In step 250, the pressure increase time T _STA is calculated by multiplying the reference pressure increase time T _STA0 calculated in step 242 by the correction count K _S. The correction coefficient K _S is a correction coefficient preset to set a short pressure increase time T _STA . Step 24 above
When the process of step 8 or the process of step 250 is finished, the process of step 252 is executed next.

In step 252, the flag XSTANB is set.
A process for turning off Y2 is executed, and a process for permitting the start of BA control is executed. When the processing of this step 252 is executed, thereafter, the BA control can be executed in the braking force control device. Step 25
When the process of 2 is finished, the routine of this time is finished.

12 to 18 are flow charts showing an example of a control routine executed by the ECU 10 to realize the BA function in the braking force control device. This routine is a routine that is repeatedly started after the execution of the BA control is permitted in step 252. When this routine is started, the process of step 260 is first executed.

At step 260, after the BA control is started, it is judged if the (I) start pressure increasing mode has already been completed. As a result, when it is determined that the (I) start pressure increasing mode is not yet finished, the process of step 262 is executed next. In step 262, the timer T _MODE
Is reset. The timer T _MODE is a timer that constantly keeps counting up toward a predetermined upper limit value. In this routine, the timer T _MODE is used as a timer for counting the duration of each control mode for realizing the BA function. When the processing of this step 262 ends, the processing of step 264 is executed next.

At step 264, the braking force control device is set to
The process for setting the assist pressure increasing state shown in FIG. 4 is executed. When the processing of this step 264 is executed,
After that, the wheel cylinder pressure P _{W / C} of each wheel starts increasing at a predetermined rate of change using the accumulator 28 as a hydraulic pressure source.
When the processing of this step 264 is completed, the next step 2
The processing of 66 is executed.

At step 266, it is judged if the count value of the timer T _MODE exceeds the pressure increase time T _STA calculated at step 248 or 250. As a result, when it is determined that T _MODE > T _STA is not established,
The processing of step 264 is executed again. According to the above processing, after the BA control is started, the pressure increasing time T _{ST A}
The braking force control device can be continuously maintained in the assist pressure increasing state until the time elapses. In the present embodiment, the processes of steps 260 to 266 realize (I) the start pressure increasing mode.

As described above, the pressure increase time T _STA is so high that the brake pedal 12 is operated at a high speed in the process of the emergency braking operation, that is, the emergency braking operation requires a quick rising of the braking force. , Set for a long time. Further, the boosting time T _{ST A} is (I) the master cylinder pressure P at the start of the BA control in consideration of the boosting gradient of the wheel cylinder pressure P _{W / C} during the execution of the start boosting mode.
Corrected based on _{M / C.} Therefore, according to the braking force control device of the present embodiment, by executing the (I) start pressure increasing mode, it is possible to generate the assist pressure Pa that accurately reflects the driver's intention.

In the present embodiment, (I) the driver's intention is reflected in the assist pressure Pa by appropriately setting the pressure increasing time T _STA in the start pressure increasing mode. The method of reflecting the driver's intention is not limited to this, and the wheel cylinder pressure P _{W /} associated with the execution of the (I) start pressure increasing mode is based on the brake operation speed generated in the process of the emergency brake operation. _The driver's intention may be reflected in the assist pressure Pa by changing the pressure increase gradient of _C.

In the braking force control system of this embodiment,
(I) When the pressure increasing time T _STA elapses after the start pressure increasing mode is started, it is determined in step 266 that T _MODE > T _STA is satisfied. In this case, in order to end the (I) start pressure increasing mode and start another control mode, the processes of step 268 and thereafter are executed. FIG. 19 is a table showing (I) the control mode executed after the start pressure increasing mode in relation to the changing speed ΔP _{M / C} at the end of the (I) start pressure increasing mode (hereinafter, the start pressure increasing mode). The table at the end is called). In the present embodiment, by the processing of step 268 and thereafter, the control mode executed next to (I) the start pressure increasing mode is determined so as to correspond to the start pressure increasing end table shown in FIG.

In step 268, (I) the changing speed ΔP _{M / C} occurring in the master cylinder pressure P _{M / C} at the end of the start pressure increasing mode is fetched. In step 270, the change speed ΔP _{M / C} acquired as described above is set to the positive predetermined value ΔP.
It is determined whether it exceeds ₁ . As a result, ΔP
If it is determined that _{M / C} > ΔP ₁ (> 0),
It can be determined that the driver is required to increase the braking force. In this case, the control mode following the start pressure increasing mode is determined to be the (II) assist pressure increasing mode, and then the process of step 272 is executed.

In step 272, in order to start the (II) assist pressure increasing mode, the braking force control device is brought into the assist pressure increasing state shown in FIG. When the processing of this step 272 is executed, thereafter, the wheel cylinder pressure P _{W / C} of each wheel is quickly increased by using the accumulator 28 as a hydraulic pressure source. When the processing of the present step 272 ends, the processing of step 274 is executed next.

At step 274, a process of turning on the flag XPAINC is executed in order to show that the currently executed control mode is the (II) assist pressure increasing mode. When the processing of this step 274 is finished, the routine of this time is finished. At step 270, ΔP
If it is determined that _{M / C} > ΔP ₁ is not established, then the process of step 276 is executed.

In step 276, the above step 268 is executed.
It is determined whether or not the change speed ΔP _{M / C} captured in step S1 is less than a predetermined negative value ΔP ₂ . As a result, ΔP _{M / C}
When it is determined that <ΔP ₂ (<0) is satisfied, it can be determined that the driver is required to reduce the braking force. In this case, the control mode following (I) the start pressure increasing mode is determined to be (III) the assist pressure reducing mode, and then the process of step 278 is executed.

In step 278, in order to start (III) the assist pressure reducing mode, the process for bringing the braking force control device into the assist pressure reducing state shown in FIG. 6 is executed. When the processing of step 278 is executed, the wheel cylinder pressure P _{W / C} of each wheel is thereafter reduced with the master cylinder pressure P _{M / C} as the lower limit. When the processing of the present step 278 ends, the processing of step 280 is then executed.

At step 280, a process of turning on the flag XPARED is executed to indicate that the control mode currently being executed is the (III) assist pressure reducing mode. When the processing of this step 280 ends, this routine ends. At step 276, ΔP
_When it is determined that _{M / C} <ΔP ₂ does not hold, that is, when the start pressure increasing mode ends, the changing speed ΔP _{M / C}
When it is determined that is maintained near "0", it can be determined that the driver is required to maintain the braking force. In this case, the process of step 282 is then executed.

In step 282, the processing for bringing the braking force control device into the assist pressure reducing state shown in FIG. 5 is executed in order to start the (IV) assist pressure holding mode. When the processing of this step 282 is executed, thereafter, the wheel cylinder pressure P _{W / C} of each wheel is maintained at a constant value without being increased or decreased. When the processing of the present step 282 is completed, the processing of step 284 is executed next.

At step 284, a process of turning on the flag XPAHOLD is executed to indicate that the control mode currently being executed is the (IV) assist pressure holding mode. When the processing of this step 284 ends, the routine of this time is ended. Steps 260-284 above
When this routine is started again after the processing of step (1) is executed, it is determined in step 260 that the (I) start pressure increasing mode has already ended. In this case, step 26
After 0, the process of step 286 is executed.

In step 286, the master cylinder pressure P _{M / C} that is occurring at that time and its changing speed Δ
The process of importing P _{M / C} is executed. This step 286
When the processing of (1) is completed, the processing of step 288 is executed next. In step 288, the control mode currently being executed in the braking force control device is determined. In step 288, when the flag XPAINC is in the on state, it is determined that the control mode currently being executed is the (II) assist pressure increasing mode. In this case, this step 288
Then, the process of step 290 shown in FIG. 13 is executed.

FIG. 20 shows the relationship between the control mode to be executed next and the change speed ΔP _{M / C} of the master cylinder pressure P _{M / C} when the control mode currently being executed is the assist pressure increasing mode. The table represented by (hereinafter, referred to as pressure increasing table) is shown. In the present embodiment, the processing from step 290 is performed so as to correspond to the pressure increasing table shown in FIG.
(II) The control mode executed next to the assist pressure increasing mode is determined.

At step 290, the master cylinder pressure P
Whether change rate [Delta] P M _{/ C} to the _{M / C} exceeds a predetermined positive value [Delta] P ₃ has occurred is determined. As a result, ΔP _{M / C} > Δ
When it is determined that P ₃ (> 0) is established, it can be determined that the driver is required to increase the braking force. In this case, the process of step 292 is executed after step 290. On the other hand, when it is determined that the change speed ΔP _{M / C} that satisfies the above conditions does not occur,
It can be determined that the driver is required to hold the braking force. In this case, the process of step 294 is executed after step 290.

In step 292, in order to make it possible to further increase the braking force, the process of continuously requesting the execution of the (II) assist pressure increasing mode, that is, the (II) assist pressure increasing mode is set as the request mode. The process is executed. Step 29
In 4, the process of requesting execution of the (IV) assist pressure holding mode, that is, the process of setting the (IV) assist pressure holding mode as the request mode is executed so that the braking force can be held. The processing of the above step 292, or this step 2
When the processing of 94 is completed, the step 3 shown in FIG.
The process of 42 is performed.

In this routine, the above step 288 is executed.
When it is determined that the flag XPARED is in the ON state, it is determined that the control mode currently being executed is the (III) assist pressure reducing mode. In this case, after step 288, the process of step 296 shown in FIG. 14 is executed. In Fig. 21, the control mode currently being executed is (II
I) When the assist pressure reducing mode is selected, the control mode to be executed next is set to the changing speed ΔP of the master cylinder pressure P _{M / C.}
A table (hereinafter referred to as a decompression table) expressed in relation to _{M / C} is shown. In the present embodiment, the control mode executed after the (III) assist pressure reduction mode is determined by the processing from step 296 onward so as to correspond to the pressure reduction table shown in FIG.

At step 296, the master cylinder pressure P
Whether change rate [Delta] P M _{/ C} below a predetermined negative value [Delta] P ₄ to _{M / C} has occurred is determined. As a result, ΔP _{M / C} <Δ
When it is determined that P ₄ (<0) is established, it can be determined that the driver is required to reduce the braking force. In this case, the process of step 298 is executed after step 296. On the other hand, when it is determined that the change speed ΔP _{M / C} that satisfies the above conditions does not occur,
It can be determined that the driver is required to hold the braking force. In this case, the process of step 300 is executed after step 296.

In step 298, in order to further reduce the braking force, the process of requesting execution of the (III) assist pressure reducing mode, that is, the process of setting (III) the assist pressure decreasing mode as the request mode, is executed. To be executed. In step 300, in order to maintain the braking force, (IV) a process for requesting execution of the assist pressure holding mode, that is, (IV)
A process of setting the assist pressure holding mode to the request mode is executed. When the process of the above step 298 or the process of this step 300 is completed, the process of step 342 shown in FIG. 18 is executed thereafter.

In this routine, the above step 288 is executed.
When it is determined that the flag XPAHOLD is ON, it is determined that the control mode currently being executed is the (IV) assist pressure holding mode. In this case, step 2 above
Subsequent to 88, the process of step 302 shown in FIG. 15 is executed. FIG. 22 shows the control mode to be executed next when the control mode currently being executed is the assist pressure holding mode, the change speed ΔP of the master cylinder pressure P _{M / C.}
Change amount of _{M / C} and master cylinder pressure P _{M / C} “P _{M / C} −
P _STA "(hereinafter referred to as" holding time table ") is shown. In the present embodiment, by the processing of step 302 and thereafter, (IV) assist is performed so as to correspond to the holding time table shown in FIG. The control mode to be executed next to the pressure holding mode is determined by the change amount "P" shown in FIG.
_{M / C-} P _STA "is the current master cylinder pressure P _{M / C} ,
Master cylinder pressure P _{M / C} detected at the start of the current control mode (hereinafter, master cylinder pressure P at start
_STA )), that is, a value corresponding to the amount of change in the master cylinder pressure P _{M / C} after the current control mode is started.

At step 302, the master cylinder pressure P
_{M / C}A predetermined value ΔP_FiveChange rate ΔP exceeding_{M / C}Raw
Same and positive predetermined value P₁Change P that exceeds_{M / C}
-P _STAIs determined. as a result,
ΔP_{M / C}> ΔP_Five(> 0) holds, and P_{M / C}-P
_STA> P₁If (> 0) holds, hold braking force
The intended driver must quickly increase the braking force.
It can be judged that the intention has started. in this case,
Following step 302, the process of step 304 is actually performed.
Done.

In step 304, the process of requesting the execution of the (II) assist pressure increasing mode, that is, the process of setting the (II) assist pressure increasing mode to the request mode, in order to enable the braking force to rise quickly. Is executed. When the process of step 304 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, the above step 302
If the condition is not satisfied, it can be determined that the driver does not intend to promptly raise the braking force. In this case, the process of step 306 is executed next.

At step 306, the master cylinder pressure P
_{M / C}A predetermined negative value ΔP₆Change rate less than ΔP_{M / C}Raw
Same and negative negative value P_FourChange P below_{M / C}
-P _STAIs determined. as a result,
ΔP_{M / C}<ΔP₆(<0) holds, and P_{M / C}-P
_STA<P_FourIf (<0) holds, hold braking force
Make sure that the intended driver quickly reduces the braking force.
It can be judged that the intention has started. in this case,
After step 306, the process of step 308 is actually executed.
Done.

In step 308, in order to quickly reduce the braking force, the process (III) requesting execution of the assist pressure reducing mode, that is, the process (III) setting the assist pressure reducing mode as the request mode is executed. This step 308
18 is completed, the next step 342 shown in FIG.
The process of is executed. On the other hand, when the condition of step 306 is not satisfied, it can be determined that the driver does not intend to reduce the braking force promptly. In this case, the process of step 310 is executed next.

At step 310, it is judged if the _count value of the timer T _MODE has reached the predetermined time T _MODE1 . The predetermined time T _MODE1 is such that when the driver operates the brake pedal 12 with the intention of rapidly changing the braking force, the change amount P _{M / C} −P _STA is a predetermined value P ₁ or more, or a predetermined value. It is a value almost equal to the upper limit value of the time required to become P ₄ or less. Therefore, when T _MODE ≧ T _MODE1 is not satisfied, the brake intended to change the braking force promptly even if neither the condition of step 302 nor the condition of step 306 is satisfied. The possibility of operation cannot be denied. In this case, the process of step 312 is then executed.

In step 312, the process of requesting the execution of the (IV) assist pressure holding mode, that is, the process of setting the (IV) assist pressure holding mode as the request mode is executed. Upon completion of the processing of this step 312, the process shown in FIG.
The process of step 342 shown in is executed. Under the condition that neither the condition of step 302 nor the condition of 306 is satisfied, T _MODE ≧ T in step 310.
_When it is determined that _MODE1 is established, it can be determined that the driver has not performed a brake operation intended to quickly change the braking force. In this case, the process of step 314 is executed after step 310 described above.

At step 314, the master cylinder pressure P
_A change amount P _{M / C} −P _STA that exceeds a predetermined positive value P ₂ in _{M / C}
Is determined. As a result, P _{M / C} −
When P _{ST A} > P ₂ (> 0) is satisfied, it can be determined that the driver who intended to maintain the braking force has started to intend to gradually increase the braking force. In this case, the process of step 316 is executed after this step 314.

In step 316, in order to gently increase the braking force, a process of requesting execution of the (V) assist pressure moderate increase mode, that is, a process of setting the (V) assist pressure moderate increase mode in the request mode is executed. It When the process of this step 316 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, when the condition of step 314 is not satisfied, it can be determined that the driver has not requested execution of the (V) assist pressure moderate increase mode. In this case, the process of step 318 is executed after step 314.

At step 318, the master cylinder pressure P
_A change amount P _{M / C} −P _STA below the negative predetermined value P ₃ in _{M / C}
Is determined. As a result, P _{M / C} −
When P _{ST A} <P ₂ (<0) holds, it can be determined that the driver who intended to maintain the braking force has started to intend to gently reduce the braking force. In this case, the process of step 320 is executed after step 318.

In step 320, the process of requesting the execution of the (VI) assist pressure gradual decrease mode, that is, the process of setting the (VI) assist pressure gradual decrease mode in the request mode, is executed in order to gently reduce the braking force. It When the process of the present step 320 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, when the condition of step 318 is not satisfied, it is determined that the driver intends to hold the braking force, that is, the driver continues to request execution of the (IV) assist pressure holding mode. it can. In this case, following step 318 above, step 3 above
Twelve processes are executed.

In this routine, the above step 288 is executed.
When it is determined that the flag XPASLINC is in the ON state, it is determined that the control mode currently being executed is the (V) assist pressure gentle increase mode. In this case, the process of step 322 shown in FIG. 16 is executed after step 288. The flag XPASLINC is a flag that is turned on when the (V) assist pressure moderate increase mode is selected as the control mode, as described later.

[0151] Figure 23, when the control mode currently being executed is the assist pressure moderately increasing mode, the control mode to be executed next, the master cylinder pressure P _{M / C} change rate [Delta] P M _{/ C}
And the master cylinder pressure P _{M / C} change amount P _{M / C} −P _STA
A table (hereinafter referred to as a slowly increasing table) represented by the relationship with In the present embodiment, the processing from step 322 is performed so as to correspond to the slowly increasing table shown in FIG.
(V) The control mode executed next to the assist pressure gentle increase mode is determined.

At step 322, the master cylinder pressure P
_{M / C}A predetermined value ΔP₇Change rate ΔP exceeding_{M / C}Raw
Same and positive predetermined value P_FiveChange P that exceeds_{M / C}
-P _STAIs determined. as a result,
ΔP_{M / C}> ΔP₇(> 0) holds, and P_{M / C}-P
_STA> P_FiveIf (> 0) holds, reduce the braking force gently.
The driver who intended to increase the braking speed
You can judge that you started to intend to increase it gently
it can. In this case, after step 322,
The process of step 324 is executed.

In step 324, the process of requesting the execution of the (II) assist pressure increasing mode, that is, the process of setting the (II) assist pressure increasing mode as the request mode, in order to enable the braking force to rise quickly. Is executed. When the process of this step 324 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, the above step 322
If the condition is not satisfied, it can be determined that the driver does not intend to increase the braking force promptly. In this case, the process of step 326 is then executed.

At step 326, it is judged if the _count value of the timer T _MODE has reached the predetermined time T _MODE2 . In the braking force control device of this embodiment, the (V) assist pressure moderate increase mode is realized by repeating the assist pressure increase state shown in FIG. 4 and the assist pressure holding state shown in FIG. The predetermined time T _MODE2 is a time defined as a time for which the braking force control device should be maintained in the assist pressure increasing state when the execution of the (V) assist pressure slowly increasing mode is requested.

Therefore, in the above step 326, T _MODE ≧ T
_When it is determined that _MODE2 is established, the period in which the braking force control device should be maintained in the assist pressure increasing state has ended, that is, the time when the braking force control device should be in the assist pressure holding state has arrived. You can determine that In this case, following step 326 above, step 328
The process of is executed.

In step 328, the process of requesting the execution of the (IV) assist pressure holding mode, that is, the process of setting the (IV) assist pressure holding mode as the request mode is executed. When the process of the present step 328 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, if it is determined in step 326 that T _MODE ≧ T _MODE2 is not established, it can be determined that the period for maintaining the braking force control device in the assist pressure increasing state has not ended. In this case, step 330 is followed by step 330.
The process of is executed.

In step 330, the process of requesting the execution of the (V) assist pressure moderate increase mode, that is, the process of setting the (V) assist pressure moderate increase mode in the request mode is executed. When the processing of this step 330 is completed, the processing of step 342 shown in FIG. 18 is then executed. According to the above process, if the condition (V) of requesting the assist pressure increasing mode (II) is not satisfied after the execution of the (V) assist pressure gradually increasing mode is started, After maintaining the request for a predetermined period T _MODE2 , the request mode can be changed to the (IV) assist pressure holding mode.

In this routine, the above step 288 is executed.
When it is determined that the flag XPASLRED is in the ON state, it is determined that the control mode currently being executed is the (VI) assist pressure gentle decrease mode. In this case, the process of step 332 shown in FIG. 17 is executed after step 288. The flag XPASLRED is a flag that is turned on when the (VI) assist pressure gradual decrease mode is selected as the control mode, as described later.

FIG. 24 shows that the control mode currently being executed is (VI).
When the assist pressure gradual decrease mode is set, the control mode to be executed next is set to the change speed ΔP of the master cylinder pressure P _{M / C.
M / C} and master cylinder pressure P _{M / C} change P _{M / C-} P
_The table shown in relation to the _STA (hereinafter referred to as the slow-decrease table) is shown. In the present embodiment, the control mode to be executed subsequent to the (VI) assist pressure gentle decrease mode is determined by the processing from step 332 onward so as to correspond to the slow decrease time table shown in FIG.

At step 332, the master cylinder pressure P
_{M / C}A predetermined negative value ΔP₈Change rate less than ΔP_{M / C}Raw
Same and negative negative value P₆Change P below_{M / C}
-P _STAIs determined. as a result,
ΔP_{M / C}<ΔP₈(<0) holds, and P_{M / C}-P
_STA<P₆If (<0) holds, reduce the braking force gently.
The driver who intended to reduce the
You can judge that you started to intend to reduce it gently
it can. In this case, after step 332, the step
The process of page 334 is executed.

In step 334, in order to promptly reduce the braking force, the process (III) requesting execution of the assist pressure reducing mode, that is, the process (III) setting the assist pressure reducing mode as the request mode is executed. This step 334
18 is completed, the next step 342 shown in FIG.
The process of is executed. On the other hand, when the condition of step 332 is not satisfied, it can be determined that the driver does not intend to reduce the braking force promptly. In this case, the process of step 336 is executed next.

At step 336, it is judged if the _count value of the timer T _MODE has reached the predetermined time T _MODE3 . In the braking force control device of the present embodiment, (III) assist pressure moderately decreasing mode is realized by repeating the assist pressure reducing state and the assist pressure holding state as described above. The predetermined time period T _MODE3 is a time period defined as a time period during which the braking force control device should be maintained in the assist pressure reducing state when (III) execution of the assist pressure moderately reducing mode is requested.

Therefore, in the above step 336, T _MODE ≧ T
If it is determined that _MODE3 is established, the period in which the braking force control device should be maintained in the assist pressure reducing state has ended, that is, the time has come when the braking force control device should be in the assist pressure holding state. Can be determined. In this case, following step 336 above, step 338
The process of is executed.

At step 338, the process of requesting the execution of the (IV) assist pressure holding mode, that is, the process of setting the (IV) assist pressure holding mode as the request mode is executed. When the process of the present step 338 is completed, the process of step 342 shown in FIG. 18 is then executed. On the other hand, if it is determined in step 336 that T _MODE ≧ T _MODE3 is not established, it can be determined that the period for maintaining the braking force control device in the assist pressure reducing state has not ended. In this case, following step 336 above, step 340
The process of is executed.

In step 340, the process of requesting the execution of the (VI) assist pressure gentle decrease mode, that is, the process of setting the (VI) assist pressure moderate decrease mode as the request mode is executed. When the processing of this step 340 is completed, next
The process of step 342 shown in is executed. According to the above processing, if the condition (III) of requesting the assist pressure reducing mode (condition of step 332) is not satisfied after the execution of the (VI) assist pressure gentle decreasing mode is started,
After maintaining the request for a predetermined period T _MODE3 , the request mode can be changed to the (IV) assist pressure holding mode.

As described above, according to this routine, by executing the processes of steps 286 to 340, the control to be executed next is executed based on the control mode currently being executed and the brake operation of the driver. The mode can be determined and the control mode can be defined as the request mode.
At step 342, it is judged if execution of the (II) assist pressure increasing mode is requested. As a result, (II)
When it is determined that the assist pressure increasing mode is requested, the process of step 344 is executed next.

At step 344, the flag XPAINC is set.
Is turned on and a flag corresponding to another control mode is turned off. When the processing of this step 344 is executed, it is determined that the control mode being executed is the (II) assist pressure increasing mode in the next processing cycle. When the process of the present step 344 is completed, the process of step 346 is next performed.

At step 346, a process for setting the braking force control device to the assist pressure increasing state shown in FIG. 4 is executed. When the process of step 346 is executed, thereafter, the wheel cylinder pressure P _{W / C of} each wheel is quickly increased by using the accumulator 28 as a hydraulic pressure source. When the process of step 346 is completed, the routine of this time is ended. If it is determined in step 342 that execution of the (II) assist pressure increasing mode is not requested, then step 3
Forty eight processes are executed.

In step 348, it is determined whether or not (III) execution of the assist pressure reducing mode is requested.
As a result, if it is determined that (III) the assist pressure reducing mode is requested, the process of step 350 is performed next. In step 350, processing of turning on the flag XPARED and turning off flags corresponding to other control modes is executed. When the process of step 350 is executed, it is determined that the control mode being executed is the (III) assist pressure reducing mode at the next process cycle. When the processing of the present step 350 is completed, the processing of step 352 is then executed.

At step 352, the process for setting the braking force control device to the assist pressure reducing state shown in FIG. 6 is executed. After the processing of this step 352 is executed, thereafter, the wheel cylinder pressure P _{W / C of} each wheel is changed to the master cylinder pressure P.
_The pressure is quickly reduced with _{M / C} as the lower limit. This step 3
When the process of 52 ends, the routine of this time is ended.

If it is determined in step 348 that (III) execution of the assist pressure reducing mode is not requested, then the processing of step 354 is executed. In step 354, it is determined whether or not execution of the (V) assist pressure moderate increase mode is requested. As a result, when it is determined that the (V) assist pressure moderate increase mode is requested, the process of step 356 is executed next.

At step 356, it is judged if the request mode has changed from the previous processing cycle to the current processing cycle. As a result, when it is determined that the request mode has changed, it can be determined that the (V) assist pressure gentle increase mode is executed after the current processing cycle. In this case, the process of step 358 is then executed. On the other hand, when it is determined that the request mode has not changed from the previous processing cycle to the current processing cycle, it can be determined that (V) the assist pressure gradual increase mode has been executed before the previous processing cycle. In this case, the process of step 358 is jumped, and then the process of step 360 is executed.

In step 358, the present master cylinder pressure P _{M / C} is stored as the starting master cylinder pressure P _STA , and the count value of the timer T _MODE is cleared to "0". When the processing of this step 358 is completed, the processing of step 360 is then executed. According to the above process, every time the execution of the (V) assist pressure gentle increase mode is newly started, the starting master cylinder pressure P _STA and the timer T _MODE can be cleared to the initial values.

At step 360, the flag XPASLI is set.
A process of turning on the NC and turning off the flags corresponding to the other control modes is executed. When the processing of this step 360 is executed, it is determined that the control mode being executed is the (V) assist pressure gentle increase mode in the next processing cycle. When the processing of this step 360 is completed, the processing of step 362 is executed next.

At step 362, a process for setting the braking force control device to the assist pressure increasing state shown in FIG. 4 is executed. When the processing of this step 362 ends, the routine of this time is ended. As described above, in this embodiment,
After the (V) assist pressure gentle increase mode is set to the request mode, the request mode is changed to the (IV) assist pressure holding mode when a predetermined period T _MODE2 has elapsed. Therefore, according to the above process, each time the execution of the (V) assist pressure gradual increase mode is requested, the wheel cylinder pressure P _{W / C} is gradually increased step by step with the predetermined period T _MODE2 as one unit. Can be made.

If it is determined in step 354 that execution of the (V) assist pressure moderate increase mode is not requested, then the processing of step 364 is executed. In step 364, it is determined whether or not execution of the (VI) assist pressure gentle decrease mode is requested. As a result, when it is determined that the execution of the (VI) assist pressure gentle decrease mode is requested, the process of step 366 is executed next.

At step 366, it is judged if the request mode has changed from the previous processing cycle to the current processing cycle. As a result, when it is determined that the request mode has changed, it can be determined that the (VI) assist pressure gradual decrease mode is executed after the current processing cycle. In this case, the process of step 368 is executed next. On the other hand, if it is determined that the request mode has not changed from the time of the previous processing cycle to the time of this processing cycle, it is determined that (VI) the assist pressure relaxation mode has been executed before the time of the previous processing cycle. it can. In this case, the process of step 368 is skipped, and then step 370 is executed.
The process of is executed.

At step 368, the above step 358 is performed.
Similarly, the process of clearing the starting master cylinder pressure P _STA and the timer T _MODE to the initial values is executed. When the processing of the present step 368 ends, the processing of step 370 is executed next. According to the above process, every time the (VI) assist pressure gentle increase mode is newly started, the starting master cylinder pressure P _STA and the timer T _MODE can be cleared to the initial values.

At step 370, the flag XPASLR is set.
A process of turning on the ED and turning off a flag corresponding to another control mode is executed. When the process of step 370 is executed, it is determined that the control mode being executed is the (VI) assist pressure moderately decreasing mode in the next process cycle. When the processing of this step 370 is completed, the processing of step 372 is executed next.

At step 372, a process for setting the braking force control device to the assist pressure reducing state shown in FIG. 6 is executed. When the processing of this step 372 ends, the routine of this time is ended. As described above, in this embodiment,
After the (VI) assist pressure gradual decrease mode is set to the request mode, the request mode is changed to the (IV) assist pressure holding mode when a predetermined period T _MODE3 has elapsed. Therefore, according to the above process, every time the execution of the (VI) assist pressure gradual decrease mode is requested, the wheel cylinder pressure P _{W / C} is gradually reduced step by step with the predetermined period T _MODE2 as one unit. Can be made.

If it is determined in step 364 that execution of the (VI) assist pressure gradual reduction mode is not requested, it can be determined that execution of the (IV) assist pressure holding mode is requested. In this case, the process of step 374 is executed after step 364 described above. Step 37
In 4, it is determined whether or not the request mode has changed from the previous processing cycle to the current processing cycle.
As a result, if it is determined that the request mode has changed,
(IV) It can be determined that the assist pressure holding mode is executed after the current processing cycle. In this case, next step 37
The process of 6 is executed. On the other hand, when it is determined that the request mode has not changed from the previous processing cycle to the current processing cycle, it can be determined that (IV) the assist pressure holding mode has been executed before the previous processing cycle. In this case, the process of step 376 is jumped, and then the process of step 378 is executed.

In step 376, the above step 35 is performed.
Similar to 6,368, processing for clearing the starting master cylinder pressure P _STA and the timer T _MODE to the initial values is executed. When the processing of the present step 376 is completed, the processing of step 378 is then executed. According to the above process, (I
V) Every time the assist pressure holding mode is newly started, the starting master cylinder pressure P _STA and the timer T _MODE can be cleared to the initial values.

At step 378, the flag XPAHOL is set.
Processing for turning on D and turning off flags corresponding to other control modes is executed. When the processing of step 378 is executed, it is determined that the control mode being executed is the (IV) assist pressure holding mode in the next processing cycle. When the processing of this step 378 is completed, the processing of step 380 is executed next.

At step 380, a process for bringing the braking force control device into the assist pressure holding state shown in FIG. 5 is executed. When the processing of this step 380 is executed, the wheel cylinder pressure P _{W / C} of each wheel can be maintained at a constant value thereafter. When the processing of step 380 is completed, the routine of this time is ended. As described above, according to the routines shown in FIGS. 12 to 18, after the execution of the BA control is started, it is possible to generate the assist pressure Pa according to the brake operation speed generated in the process of the emergency brake operation. Along with the execution of the BA control, the wheel cylinder pressure P _{W / C} is appropriately increased _/ decreased in response to the increase _/ decrease of the master cylinder pressure P _{M / C} , that is, in response to the driver's brake operation. be able to. Therefore, according to the braking force control device of the present embodiment, when the driver performs the emergency braking operation, the braking force intended by the driver is promptly generated, and the braking force is constantly controlled during the execution of the BA control. The driver's intention can be reflected in the power.

In the above embodiment, the ECU 10
Calculates the changing speed ΔP _{M / C} of the master cylinder pressure P _{M / C} based on the output signal of the hydraulic pressure sensor 144, whereby the “operation speed detecting means” according to claim 1 is configured so that the ECU 10
The "emergency brake operation detecting means" according to claim 1 by executing the routine shown in FIGS. 8 and 9 above.
However, the ECU 10 executes the above steps 240, 242, 252.
And the processing of 260 to 266 realizes the "braking hydraulic pressure increasing means" of the first aspect.

Further, in the above embodiment, the accumulator 28 corresponds to the "first assist pressure generating means" described in claim 2, and the ECU 10 executes the steps 240, 242, 252 and 260-266. By executing the processing, the "assist time control means" according to claim 2 causes the ECU 10 to execute the above steps 246, 2
By executing the processes of 48 and 250, the pressure increasing time correction means according to claim 4 is realized.

Further, in the above embodiment, the accum
Lator 28, STR94 and SA _-390 is the claim
It corresponds to the “second assist pressure generating means” described in 3.
Both after the conditions for the second standby state and after are met
Then, the ECU 10 determines that the change speed ΔP_{M / C}Maximum value ΔP_MAX
In order to realize a pressure increase gradient according to
Only in a predetermined cycle, the assist pressure increase state (shown in Fig. 4 above)
State) and assist pressure holding state (state shown in FIG. 5 above)
The reed of claim 3, wherein the reed is repeatedly realized.
Strike control means "is realized.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 25 is a system configuration diagram of a pump-up type braking force control device (hereinafter, simply referred to as a braking force control device) corresponding to the second embodiment of the invention. 25, the same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

The braking force control device of this embodiment is a device suitable as a braking force control device for a front engine / rear drive type vehicle (FR vehicle). The braking force control device of this embodiment is controlled by the ECU 10. ECU 10
Controls the operation of the braking force control device by executing the control routines shown in FIGS. 8 to 10 and 12 to 18, as in the case of the first embodiment described above.

The braking force control device has a brake pedal 12. A brake switch 14 is arranged near the brake pedal 12. The ECU 10 determines the brake pedal 1 based on the output signal of the brake switch 14.
It is determined whether 2 is depressed. The brake pedal 12 is connected to the vacuum booster 400. The vacuum booster 400 has a brake pedal 12
When is depressed, an assist force Fa having a predetermined boosting ratio to the brake pedal force F is generated. A master cylinder 402 is fixed to the vacuum booster 400. The master cylinder 402 is a tandem center valve type master cylinder, and has a first hydraulic chamber 404 and a second hydraulic chamber 406 therein. First
A master cylinder pressure P _{M / C} is generated in the hydraulic chamber 404 and the second hydraulic chamber 406 according to the resultant force of the brake pedal force F and the assist force Fa.

A reservoir tank 408 is arranged above the master cylinder 402. Reservoir tank 408
A front reservoir passage 410 and a rear reservoir passage 412 are in communication with each other. The front reservoir passage 410 includes a front reservoir cut solenoid 414.
(Hereinafter, referred to as SRCF414) is in communication. Similarly, a rear reservoir cut solenoid 416 (hereinafter referred to as SRCR 416) communicates with the rear reservoir passage 412.

A front pump passage 418 is further communicated with the SRCF 414. Similarly, SRCR416
A rear pump passage 420 communicates with the. SRCF
Reference numeral 414 is a two-position solenoid valve that shuts off the front reservoir passage 410 and front pump passage 418 by being turned off and conducts them by turning them on. The SRCR 416 is a two-position solenoid valve that is turned off to shut off the rear reservoir passage 412 and the rear pump passage 420 and is turned on to bring them into conduction.

First hydraulic chamber 40 of master cylinder 402
The first hydraulic pressure passage 422 and the second hydraulic pressure passage 424 communicate with the fourth hydraulic chamber 406 and the second hydraulic chamber 406, respectively. In the first hydraulic pressure passage 422, a front right master cut solenoid 426 (hereinafter, referred to as SMFR426), and
Left front master cut solenoid 428 (hereinafter SMFL4
28) communicates with each other. On the other hand, the second hydraulic pressure passage 42
4 is a rear master cut solenoid 430 (hereinafter, S
(Referred to as MR430).

The hydraulic pressure passage 432 provided corresponding to the right front wheel FR communicates with the SMFR 426. Similarly,
The SMFL 428 is in communication with a hydraulic passage 434 provided corresponding to the left front wheel FL. Further, the SMR 430 communicates with a hydraulic passage 436 provided corresponding to the left and right rear wheels RL and RR. SMFR426, SMFL42
8 and the SMR 430 are provided with constant pressure release valves 438, 440 and 442, respectively. SMFR4
26 makes the first fluid pressure passage 422 and the fluid pressure passage 432 electrically conductive when it is turned off, and the first fluid pressure passage 42 through the constant pressure release valve 438 when it is turned on.
It is a two-position solenoid valve that connects 2 and the hydraulic passage 432. Further, the SMFL 426 brings the first hydraulic passage 422 and the hydraulic passage 434 into a conductive state when turned off, and the constant pressure release valve 440 to bring the first hydraulic passage through the first hydraulic passage 434 when turned on. This is a two-position solenoid valve that connects the fluid pressure passage 434 and the fluid pressure passage 434. Similarly, SMR430
When turned off, the second hydraulic passage 424 and the hydraulic passage 436 are brought into conduction, and when turned on, the second hydraulic passage 424 and the hydraulic passage are connected via the constant pressure release valve 442. It is a two-position solenoid valve that communicates with 436.

Between the first hydraulic pressure passage 422 and the hydraulic pressure passage 432, and from the first hydraulic pressure passage 422 side, the hydraulic pressure passage 43 is formed.
Check valve 44 that allows only the flow of fluid toward the 2 side
4 are provided. Similarly, the first hydraulic pressure passage 422 is provided between the first hydraulic pressure passage 422 and the hydraulic pressure passage 434 and between the second hydraulic pressure passage 424 and the hydraulic pressure passage 436, respectively.
Check valve 446 that allows only the flow of fluid from the hydraulic pressure passage 434 side to the hydraulic pressure passage 434 side, and check valve 448 that allows only the flow of fluid from the second hydraulic pressure passage 424 side to the hydraulic pressure passage 436 side. It is arranged.

Hydraulic passage 4 provided corresponding to the left and right front wheels
32, 434 and the hydraulic passages 436 provided corresponding to the left and right rear wheels, like the first embodiment, the holding solenoid S ** H, the pressure reducing solenoid S ** R, the wheel cylinders 120 to. 126 and the check valves 128 to 134 are in communication. In addition, the holding solenoid SFR for the left and right front wheels
A front depressurization passage 450 communicates with R112 and SFLR114. Further, a rear pressure reducing passage 452 communicates with the holding solenoids SRRR116 and SRLR118 of the left and right rear wheels.

A front reservoir 454 and a rear reservoir 455 communicate with the front pressure reducing passage 450 and the rear pressure reducing passage 452, respectively. The front reservoir 454 and the rear reservoir 455 respectively include the check valve 4
56, 458 through the suction side of the front pump 460,
And, it communicates with the suction side of the rear pump 462. The discharge side of the front pump 460 and the rear pump 46
The discharge side of 2 is a damper 4 for absorbing the pulsation of the discharge pressure.
It communicates with 64,466. The damper 464 includes a right front pump passage 468 provided corresponding to the right front wheel FR and a left front pump passage 470 provided corresponding to the left front wheel FL.
Is in communication with. On the other hand, the damper 466 causes the fluid pressure passage 43
It communicates with 6.

The front right pump passage 468 communicates with the hydraulic passage 432 via a front right pump solenoid 472 (hereinafter referred to as SPFL 472). The front left pump passage 470 is connected to the front left pump solenoid 474 (hereinafter, referred to as SPF).
(Referred to as R474) and communicates with the hydraulic passage 434. The SPFL 472 is a two-position solenoid valve that is turned off to bring the front right pump passage 468 and the hydraulic passage 432 into conduction, and turned on to shut them off. Similarly, SPFR47
4 is turned off so that the left front pump passage 47 is
It is a two-position solenoid valve that brings 0 and the hydraulic passage 434 into a conductive state and turns them into an shut-off state by turning them on.

Between the hydraulic pressure passage 432 and the right front pump passage 468, the right front pump passage 468 is provided from the hydraulic pressure passage 432 side.
Constant pressure release valve 476 that allows only the flow of fluid toward the side
Is provided. Similarly, a constant pressure release valve 478 is provided between the hydraulic pressure passage 434 and the left front pump passage 470 to allow only a fluid flow from the hydraulic passage 434 side to the left front pump passage 470 side.

In the vicinity of each wheel, a wheel speed sensor 136,
138, 140, 142 are arranged. ECU 10
Detects the rotational speed V _W of each wheel based on the output signal of the wheel speed sensors 136-142. A hydraulic pressure sensor 144 is arranged in the second hydraulic pressure passage 424 that communicates with the master cylinder 402. The ECU 10 detects the master cylinder pressure P _{M / C} based on the output signal of the hydraulic pressure sensor 144.

Next, the operation of the braking force control system of this embodiment will be described. The braking force control apparatus according to the present embodiment switches the states of various electromagnetic valves arranged in the hydraulic circuit, thereby providing a normal braking function, an ABS function, and a B function.
A function is realized. The normal braking function is realized by turning off all the electromagnetic valves included in the braking force control device, as shown in FIG. Hereinafter, the state shown in FIG. 25 is referred to as a normal braking state. Further, the control for realizing the normal braking function in the braking force control device is called normal braking control.

In the normal braking state shown in FIG. 25,
Wheel cylinders 120, 122 for left and right front wheels FL, FR
Together with the master cylinder 4 via the first hydraulic passage 422.
02 to the first hydraulic chamber 404. In addition, the wheel cylinders 124 and 126 for the left and right rear wheels RL and RR are
It communicates with the second hydraulic chamber 406 of the master cylinder 402 via the hydraulic passage 424. In this case, the wheel cylinder pressure P _{W / C} of the wheel cylinders 120 to 126 is always controlled to be equal to the master cylinder pressure P _{M / C.} Therefore, FIG.
According to the state shown in FIG. 5, the normal braking function is realized.

In the ABS function, in the state shown in FIG. 25, the front pump 460 and the rear pump 462 are turned on, and the holding solenoid S ** H and the pressure reducing solenoid S ** R are appropriately driven according to the ABS request. It is realized by doing. Hereinafter, the control for realizing the ABS function in the braking force control device will be referred to as ABS control.

The ECU 10 starts the ABS control when the vehicle is in the braking state and an excessive slip ratio is detected for any of the wheels. The ABS control is started under the condition that the brake pedal 12 is depressed, that is, under the condition that the master cylinder 402 generates a high master cylinder pressure P _{M / C.} During execution of the ABS control, the master cylinder pressure P _{M / C} passes through the first hydraulic pressure passage 422 and the second hydraulic pressure passage 424, and hydraulic pressure passages 432, 434 provided corresponding to the left and right front wheels, respectively. and,
It is guided to a hydraulic pressure passage 436 provided corresponding to the left and right rear wheels. Therefore, if the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed under such a condition, the wheel cylinder pressure P _{W / C} of each wheel can be increased. Hereinafter, this state is referred to as (i) pressure increasing mode.

When both the holding solenoid S ** H and the pressure reducing solenoid S ** R are closed during the ABS control, the wheel cylinder pressure P _{W / C} of each wheel can be held. . Hereinafter, this state is referred to as (ii) holding mode. Further, while the ABS control is being executed, the holding solenoid S ** H is closed and the pressure reducing solenoid S ** H is closed.
When R is opened, the wheel cylinder pressure P of each wheel is
_{W / C} can be depressurized. Below, this state is (iii)
It is called the decompression mode.

The ECU 10 controls the slip state of each wheel so that the above-mentioned (i) pressure increasing mode, (ii) holding mode, and (iii) pressure reducing mode are appropriately realized for each wheel during ABS control. The holding solenoid S ** H and the pressure reducing solenoid S ** R are controlled accordingly. Holding solenoid S **
When the H and the pressure reducing solenoid S ** R are controlled as described above, the wheel cylinder pressure P _{W / C of} all the wheels is controlled to an appropriate pressure that does not cause an excessive slip ratio in the corresponding wheels. . Thus, according to the above control,
The ABS function can be realized in the braking force control device.

When the pressure reducing mode is performed for each wheel during execution of the ABS control, the brake fluid in the wheel cylinders 120 to 126 passes through the front pressure reducing passage 450 and the rear pressure reducing passage 452, and then the front reservoir 454 and the rear reservoir 455. Flow into. Front reservoir 4
54 and the rear reservoir 455, the brake fluid flows into the front pump 460 and the rear pump 462.
And is supplied to the hydraulic passages 432, 434, 436.

A part of the brake fluid supplied to the hydraulic pressure passages 432, 434, 436 flows into the wheel cylinders 120 to 126 when the pressure increasing mode is performed on each wheel. The rest of the brake fluid flows into the master cylinder 402 to make up for the outflow of the brake fluid. Therefore, according to the system of the present embodiment, the ABS
An excessive stroke does not occur in the brake pedal 12 during the execution of the control.

26 to 28 show the states of the braking force control device for realizing the BA function. The ECU 10
The BA function is realized by appropriately realizing the states shown in FIG. 26 to FIG. 28 after a brake operation that requires a rapid rise of the braking force by the driver, that is, after performing an emergency brake operation. Hereinafter, in the braking force control device, control for realizing the BA function is referred to as BA control.

FIG. 26 shows an assist pressure increasing state realized during execution of the BA control. The assist pressure increase state is B
When it is necessary to increase the wheel cylinder pressure P _{W / C} of each wheel during execution of A control, that is, during BA control
This is realized when execution of (I) start pressure increasing mode, (II) assist pressure increasing mode, and (V) assist pressure slowly increasing mode is requested.

In the system of this embodiment, the assist pressure increasing state during the BA control is as shown in FIG. 26, where the reservoir cut solenoids SRCF414 and SRCR41 are used.
6, and the master cut solenoid SMFR426,
The SMFL 428 and SMR 430 are turned on, and
It is realized by turning on the front pump 460 and the rear pump 462.

When the assist pressure increasing state shown in FIG. 26 is realized, the brake fluid stored in the reservoir tank 408 is removed from the front pump 460 and the rear pump 4.
Liquid pressure passages 432, 434, 436 are pumped up by 62.
Is supplied to. In the assist pressure increasing state, the hydraulic pressure passage 43
The internal pressure of 2,434,436 is the constant pressure release valve 438,44.
The hydraulic pressure passages 432, 434, 4 are maintained until the valve opening pressure of 0,442 is exceeded and the master cylinder pressure P _{M / C} is increased to a high pressure.
The flow of brake fluid from 36 to the master cylinder 402 is SMFR326, SMFL328, SMR3.
Blocked by 30.

Therefore, when the assist pressure increasing state shown in FIG. 26 is realized, thereafter, the hydraulic pressure passages 432, 434, 434 are formed.
At 436, a hydraulic pressure higher than the master cylinder pressure P _{M / C} is generated. In the assist pressure increasing state, the wheel cylinders 120 to 126 and their corresponding hydraulic pressure passages 33
2, 334 and 336 are maintained in a conductive state. Therefore, when the assist pressure increasing state is realized, thereafter, the wheel cylinder pressure P _{W / C} of all the wheels is promptly changed to the master cylinder pressure P _{M / C} by using the front pump 460 or the rear pump 462 as the hydraulic pressure source. The pressure is raised to exceed the pressure.

In the assist pressure increasing state shown in FIG. 26, the fluid pressure passages 434, 432, 436 communicate with the master cylinder 402 via the check valves 444, 446, 448, respectively. Therefore, when the master cylinder pressure P _{M / C} is greater than the wheel cylinder pressure P _{W / C} of each wheel, even in the assist pressure increasing state, the wheel cylinder pressure P _W of the master cylinder 402 as a fluid pressure source _{/ C} can be boosted.

FIG. 27 shows an assist pressure holding state realized during execution of BA control. The assist pressure holding state is B
This is realized when it is necessary to maintain the wheel cylinder pressure P _{W / C} of each wheel during the execution of the A control, that is, when the (IV) assist pressure retention mode is required during the BA control. As shown in FIG. 27, the assist pressure holding state is such that the master cut solenoids SMFR426, SMFL428, SMR4.
It is realized by turning 30 on.

In the assist pressure holding state shown in FIG. 27, the front pump 460, the reservoir tank 408, and
The rear pump 462 and the reservoir tank 408 are shut off by the SRCFs 414 and 416, respectively. Therefore, in the assist pressure holding state, the hydraulic pressure passages 432, 432 are connected from the front pump 460 and the rear pump 462.
No fluid is discharged to 434 and 436. Further, in the assist pressure holding state shown in FIG. 27, the hydraulic pressure passage 4
32,434,436 are SMFR426, SMFL4
24, substantially separated from the master cylinder 402 by the SMR 430. Therefore, according to the assist pressure holding state shown in FIG. 27, the wheel cylinder pressures P _{W / C} of all the wheels can be held at a constant value.

FIG. 28 shows an assist pressure reducing state realized during execution of the BA control. The assist pressure reduction state is B
When it is necessary to reduce the wheel cylinder pressure P _{W / C} of each wheel during execution of A control, that is, during BA control (III)
It is realized when execution of the assist pressure reduction mode and (VI) assist pressure gentle reduction mode is requested. The assist pressure reducing state is realized by turning off all the solenoids as shown in FIG.

In the assist pressure reducing state shown in FIG. 28, front pump 460 and rear pump 462 are separated from reservoir tank 408. Therefore, from the front pump 462 and the rear pump 462 to the hydraulic passage 43.
No fluid is discharged to 2,434,436. Further, in the assist pressure reducing state, the wheel cylinders 120 to 126 of each wheel and the master cylinder 402 are in a conductive state. Therefore, when the assist pressure reducing state is realized, the wheel cylinder pressure P _{W / C} of all the wheels can be reduced with the master cylinder pressure P _{M / C} as the lower limit value.

In this embodiment, when the driver performs an emergency braking operation, the ECU 10 performs the assist pressure increasing state shown in FIGS. 26 to 28, as in the case of the first embodiment. The BA function is realized by combining the assist pressure holding state and the assist pressure reducing state.
Therefore, according to the braking force control device of the present embodiment, as in the case of the first embodiment described above, when the driver performs the emergency braking operation, the braking force intended by the driver can be promptly provided. It is possible to reflect the driver's intention in the braking force during the generation and BA control.

In the braking force control system of the present embodiment, when the above-mentioned BA control is started, the wheel cylinder pressure P _{W / C of} each wheel is quickly increased thereafter, so that any wheel is excessively increased. Slip rate may occur. In such a case, the ECU 10 may use BA + ABS
Start control. The operation of the braking force control device associated with the BA + ABS control will be described below with reference to FIGS. 29 and 30 together with FIG.

The braking force control system of this embodiment is BA + AB.
After the S control is started, when the driver performs a brake operation intended to increase the braking force, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to a pressure according to the ABS control request, The wheel cylinder pressure P _{W / C} of the other wheels is increased. FIG. 29 shows a state (hereinafter referred to as assist pressure boosting (ABS)) that is realized to fulfill the above function during execution of BA + ABS control in which the left front wheel FL is the ABS target wheel.
(Referred to as a state). The assist pressure increase (ABS) state is the rear reservoir cut solenoid SRCR416 and the master cut solenoids SMFR426 and SMF.
This is realized by turning on L428 and SMR430, turning on the front pump 460 and the rear pump 462, and appropriately controlling the holding solenoid SFLH106 and the pressure reducing solenoid SFLR114 of the left front wheel FL according to the ABS control request.

In the assist pressure increase (ABS) state,
Brake fluid discharged from the rear pump 462 is supplied to the wheel cylinders 124 and 126 of the left and right rear wheels RL and RR, as in the assist pressure increasing state shown in FIG. Therefore, when the assist pressure increase (ABS) state is realized, the wheel cylinder pressure P _{W / C} of the left and right rear wheels RL, RR is the same as when the assist pressure increase state is realized during BA control. Boosted.

BA + with the left front wheel FL as the ABS target wheel
The ABS control is started by executing (ii) the pressure reducing mode for the left front wheel FL. Therefore, the brake fluid flows into the front reservoir 454 at the same time when the BA + ABS control is started. In the assist pressure increase (ABS) state shown in FIG. 29, the front pump 460
Sucks the brake fluid that has flowed into the front reservoir 454 in this manner and pumps it.

The brake fluid pumped by the front pump 460 is mainly supplied to the wheel cylinder 120 of the right front wheel FR and also to the wheel cylinder 122 when (i) the pressure increasing mode is executed for the left front wheel FL. To be done. According to the above control, the wheel cylinder pressure P _{W / C} of the right front wheel FR is increased as in the case where the assist pressure increasing state is realized during the BA control, and the wheel cylinder pressure P of the left front wheel FL is increased. _{W / C} can be controlled to an appropriate value that does not cause an excessive slip ratio on the left front wheel FL.

As described above, according to the assist pressure increase (ABS) state shown in FIG. 29, the wheel cylinder pressure P _{W / C} of the left front wheel FL, which is the ABS target wheel, is controlled to a pressure according to the ABS control request. At the same time, the wheel cylinder pressure P _{W / C} of the right front wheel FR and the left and right rear wheels RL, RR, which are the non-target wheels of the ABS control, is promptly increased as in the case where the assist pressure increasing state is realized during the BA control. Can be boosted.

The braking force control system of this embodiment is BA + AB.
After the S control is started, when the driver performs a brake operation intended to maintain the braking force, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to a pressure according to the ABS control request, The wheel cylinder pressure P _{W / C} of other wheels is maintained. FIG. 30 is a state realized to fulfill the above function during execution of the BA + ABS control in which the left front wheel FL is the ABS target wheel (hereinafter referred to as assist pressure holding (ABS)).
(Referred to as a state). The assist pressure holding (ABS) state is the master cut solenoid SMFR426, SMFL.
428 and SMR430 are turned on, the front pump 460 and the rear pump 462 are turned on, the holding solenoid SFRH104 of the right front wheel FR is turned on,
In addition, it is realized by appropriately controlling the holding solenoid SFLH 106 and the pressure reducing solenoid SFLR 114 of the left front wheel FL in response to a request for ABS control.

In the assist pressure holding (ABS) state,
The rear pump 462 is shut off from the reservoir tank 408 as in the case where the assist pressure holding state shown in FIG. 27 is realized. Further, the hydraulic passage 430 is substantially cut off from the master cylinder 402 as in the case where the assist pressure holding state shown in FIG. 27 is realized. For this reason,
When the assist pressure holding (ABS) state is realized, the wheel cylinder pressure P _{W / C} of the left and right rear wheels RL, RR is held at a constant value as in the case where the assist pressure holding state is realized during BA control. It

At the same time as the assist pressure holding (ABS) state is realized in the front reservoir 454, or before the assist pressure holding (ABS) state is realized,
The brake fluid that has flowed out of the wheel cylinder 122 is stored. The front pump 460 draws in and pumps the brake fluid stored in the front reservoir 454 while the assist pressure holding (ABS) state is realized.

[0229] The right front wheel FR in the assist pressure holding state
Wheel cylinder 120 of SF
It is separated from the front pump 460. For this reason,
Brake full pumped by front pump 460
Is supplied only to the wheel cylinder 122 of the left front wheel FL.
To be done. In addition, the front pump 460 to the foil sill
Inflow of brake fluid into the da 122 is to the left front wheel FL.
(I) Only allowed if boost mode is activated.
It According to the above processing, the wheel cylinder of the right front wheel FR
Pressure P_{W / C}Is maintained at a constant value and the left front wheel FL
Il cylinder pressure P _{W / C}However, excessive slip on the left front wheel FL
It is controlled to an appropriate pressure that does not generate a rate.

As described above, according to the assist pressure increase (ABS) state shown in FIG. 30, the wheel cylinder pressure P _{W / C} of the left front wheel FL which is the ABS target wheel is set to an appropriate pressure according to the ABS control request. The wheel cylinder pressure P _{W / C} of the right front wheel FR and the left and right rear wheels RL, RR, which are the non-target wheels of the ABS control, is kept constant while being controlled in the same manner as when the assist pressure holding state is realized during the BA control. Can be held at a value.

The braking force control system of this embodiment is BA + AB.
After the S control is started, when the driver performs a brake operation intended to reduce the braking force, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to a pressure according to the ABS control request, The wheel cylinder pressure P _{W / C} of the other wheels is reduced. The above-mentioned function realizes the assist pressure reduction state shown in FIG.
In order to realize (i) pressure increasing mode, (ii) holding mode, and (iii) pressure reducing mode in response to the ABS control request, the holding solenoid S ** H and the pressure reducing solenoid S ** R are appropriately used.
It is realized by controlling. Hereinafter, a state in which such control is executed is referred to as an assist pressure reduction (ABS) state.

That is, when the assist pressure reduction (ABS) state is realized, all the holding solenoids S ** H
Communicate with the master cylinder 402. Therefore, when the assist pressure reduction (ABS) control is realized, it is possible to reduce the wheel cylinder pressure P _{W / C} of the non-controlled target wheel of the ABS control with the master cylinder pressure P _{M / C} as the lower limit value.
Further, for the wheel subject to ABS control, the wheel cylinder pressure P _{W / C} can be held or reduced by implementing (ii) the holding mode and (iii) the pressure reducing mode.

By the way, the assist pressure reduction (ABS) state is used when the driver intends to reduce the braking force, that is, when it is not necessary to increase the wheel cylinder pressure P _{W / C of} any wheel. Will be realized. Therefore, if the (ii) holding mode and (iii) depressurization mode can be realized for the ABS target wheel as described above, the wheel cylinder pressure P _{W / C} of the ABS target wheel is appropriately controlled to the pressure required by the BA + ABS control. can do.

As described above, the assist pressure reduction (A
According to the (BS) state, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to an appropriate pressure according to the ABS control request, the right front wheel FR and the left and right rear wheels RL which are non-target wheels of the ABS control. , RR wheel cylinder pressure P _{W / C} to B
As in the case where the assist pressure reducing state is realized during the A control, the master cylinder pressure P _{M / C} can be reduced with the lower limit value.

As described above, according to the braking force control apparatus of the present embodiment, when the BA control is started and an excessive slip ratio occurs in any of the wheels, the wheel cylinder pressure P of the ABS target wheel is increased. _The ABS function of suppressing the _{W / C} to an appropriate pressure required by the ABS control and the wheel cylinder pressure P _{W / C} of the non-controlled target wheel of the ABS control are higher than the master cylinder pressure P _{M / C.} In the area, the BA function for increasing / decreasing according to the brake operation of the driver can be realized at the same time.

Next, a third embodiment of this embodiment will be described with reference to FIGS. 31 to 36. FIG. 31 is a system configuration diagram of a pump-up type braking force control device (hereinafter, simply referred to as a braking force control device) corresponding to the third embodiment of the invention. In FIG. 31, the same parts as those shown in FIG. 25 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

The braking force control device of this embodiment is suitable as a braking force control device for a front engine / front drive type vehicle (FF vehicle). The braking force control device of this embodiment is controlled by the ECU 10. ECU
10 is an operation of the braking force control device by executing the control routines shown in FIGS. 8 to 10 and FIGS. 12 to 18 as in the case of the first and second embodiments described above. To control.

The braking force control device is provided with a brake pedal 12. A brake switch 14 is arranged near the brake pedal 12. The ECU 10 determines the brake pedal 1 based on the output signal of the brake switch 14.
It is determined whether 2 is depressed. The brake pedal 12 is connected to the vacuum booster 400. Further, the vacuum booster 400 is fixed to the master cylinder 402. A first hydraulic chamber 404 and a second hydraulic chamber 406 are formed inside the master cylinder 402. First hydraulic chamber 404 and second hydraulic chamber 406
Inside the, the brake pedal force F and the vacuum booster 4
00, the master cylinder pressure P _{M / C} corresponding to the resultant force with the assist force Fa is generated.

A reservoir tank 408 is arranged above the master cylinder 400. Reservoir tank 408
The first reservoir passage 500 and the second reservoir passage 502 communicate with each other. In the first reservoir passage 500, a first reservoir cut solenoid 504 (hereinafter, SR
(Referred to as C _-1 504). Similarly, in the second reservoir passage 502, the second reservoir cut solenoid 5
06 (hereinafter, referred to as SRC- ₂ 506) are in communication.

A first pump passage 508 is further communicated with the SRC _-1 504. Similarly, the second pump passage 510 communicates with the SRC- ₂ 506. SRC _-1 5
When 04 is turned off, the first reservoir passage 50
This is a two-position solenoid valve that shuts off 0 from the first pump passage 508 and brings them into conduction by being turned on. The SRC- ₂ 506 is a two-position solenoid valve that shuts off the second reservoir passage 502 and the second pump passage 510 by being turned off, and conducts them by being turned on. is there.

First hydraulic chamber 40 of master cylinder 402
The first hydraulic pressure passage 422 and the second hydraulic pressure passage 424 communicate with the fourth hydraulic chamber 406 and the second hydraulic chamber 406, respectively. A first master cut solenoid 512 (hereinafter referred to as SMC _-1 512) communicates with the first hydraulic pressure passage 422. On the other hand, a second master cut solenoid 514 (hereinafter referred to as SMC- ₂ 514) communicates with the second hydraulic pressure passage 424.

The SMC _-1 512 has a first pump pressure passage 5
16 and a hydraulic passage 518 provided corresponding to the left rear wheel RL
And are in communication. The first pump pressure passage 516 has a first
A pump solenoid 520 (hereinafter, referred to as SMV- ₁ 520) is in communication. The SMV- ₁ 520 is further communicated with a hydraulic pressure passage 522 provided corresponding to the front right wheel FR. A constant pressure release valve 524 is provided inside the SMV- ₁ 520. The SMV- ₁ 520 brings the first pump pressure passage 516 and the hydraulic passage 522 into conduction when turned off, and the constant pressure release valve 5 when turned on.
It is a two-position solenoid valve that connects them via 24. Between the first pump pressure passage 516 and the fluid pressure passage 522, and from the first pump pressure passage 516 side, the fluid pressure passage 52 is formed.
Check valve 52 that allows only the flow of fluid toward the 2 side
6 are provided.

The SMC _-2 514 has a second pump pressure passage 5
28 and the hydraulic passage 530 provided corresponding to the right rear wheel RR
And are in communication. The second pump pressure passage 528 has a second
A pump solenoid 532 (hereinafter referred to as SMV- ₂ 532) is in communication. The SMV- ₂ 532 is further communicated with a hydraulic passage 534 provided corresponding to the left front wheel FL. A constant pressure release valve 536 is provided inside the SMV- ₂ 532. The SMV- ₂ 532 brings the second pump pressure passage 528 and the fluid pressure passage 534 into conduction when turned off, and the constant pressure release valve 5 when turned on.
A two-position solenoid valve that connects them via 36. Between the first pump passage 528 and the hydraulic passage 534, and from the second pump pressure passage 528 side, the hydraulic passage 53
Check valve 53 that allows only the flow of fluid toward the 6 side
8 are provided.

Constant pressure release valves 540 and 542 are provided inside the SMC _-1 512 and SMC _-2 514, respectively. The SMC- ₁ 512 electrically connects the first hydraulic pressure passage 422 and the hydraulic pressure passage 518 (and the first pump pressure passage 516) when turned off and releases the constant pressure when turned on. A two-position solenoid valve that connects them via a valve 540. In addition, the SMC- ₂ 514, when turned off, causes the second hydraulic passage 424 and the hydraulic passage 5 to
It is a two-position solenoid valve that connects 30 (and the second pump pressure passage 528) to each other and connects them via the constant pressure release valve 442 when turned on.

A check valve 544 is provided between the first hydraulic pressure passage 422 and the hydraulic pressure passage 518 to allow only the flow of fluid from the first hydraulic pressure passage 422 side toward the hydraulic pressure passage 518 side. ing. Similarly, between the second hydraulic pressure passage 424 and the hydraulic pressure passage 530, the check valve 54 that allows only the flow of the fluid from the second hydraulic pressure passage 424 side toward the hydraulic pressure passage 530 side.
6 are provided.

The holding solenoid S * is provided in the four hydraulic passages 516, 522, 528, 534 provided corresponding to the left and right front wheels and the left and right rear wheels, as in the case of the first and second embodiments. * H, pressure reducing solenoid S ** R, wheel cylinders 120 to 126, and check valves 128 to 134 are in communication. Further, the pressure reducing solenoids SFRR112 and SRLR118 of the right front wheel FR and the left rear wheel RL are
The first decompression passage 548 communicates. Furthermore, the left front wheel FL
A second pressure reducing passage 550 communicates with the pressure reducing solenoids SFLR 114 and SRRR 116 of the right rear wheel RR.

First pressure reducing passage 548 and second pressure reducing passage 5
A first reservoir 552 and a second reservoir 554 are in communication with 50. In addition, the first reservoir 552
The second reservoir 554 and check valve 556, respectively.
It communicates with the suction side of the first pump 560 and the suction side of the second pump 562 via 558. First pump 5
The discharge side of 60 and the discharge side of the second pump 562 are
It communicates with dampers 564 and 566 for absorbing the pulsation of the discharge pressure. The dampers 564 and 566 communicate with the hydraulic passages 522 and 534, respectively.

In the vicinity of each wheel, a wheel speed sensor 136,
138, 140, 142 are arranged. ECU 10
Detects the rotational speed V _W of each wheel based on the output signal of the wheel speed sensors 136-142. A hydraulic pressure sensor 144 is provided in the second hydraulic pressure passage 324 that communicates with the master cylinder 302. The ECU 10 detects the master cylinder pressure P _{M / C} based on the output signal of the hydraulic pressure sensor 144.

Next, the operation of the braking force control system of this embodiment will be described. The braking force control apparatus according to the present embodiment switches the states of various electromagnetic valves arranged in the hydraulic circuit, thereby providing a normal braking function, an ABS function, and a B function.
A function is realized. The normal braking function is realized by turning off all the solenoid valves included in the braking force control device, as shown in FIG. Hereinafter, the state shown in FIG. 31 is referred to as a normal braking state. Further, the control for realizing the normal braking function in the braking force control device is called normal braking control.

In the normal braking state shown in FIG. 31,
The wheel cylinder 120 of the right front wheel FR and the wheel cylinder 126 of the left rear wheel RL both communicate with the first hydraulic chamber 404 of the master cylinder 402 via the first hydraulic pressure passage 422. Further, the wheel cylinder 122 of the left front wheel FL and the wheel cylinder 124 of the right rear wheel RR both communicate with the second hydraulic chamber 406 of the master cylinder 402 via the second hydraulic pressure passage 424. In this case, the wheel cylinder 12
The wheel cylinder pressure P _{W / C} of 0 to 126 is always controlled to be equal to the master cylinder pressure P _{M / C.} Therefore, according to the state shown in FIG. 31, the normal braking function is realized.

In the ABS function, in the state shown in FIG. 31, the first pump 560 and the second pump 562 are turned on, and the holding solenoid S ** H and the pressure reducing solenoid S ** R are turned on in response to the ABS request. It is realized by driving appropriately. Hereinafter, the control for realizing the ABS function in the braking force control device will be referred to as ABS control.

During execution of the ABS control, four hydraulic pressure passages 518, 5 provided corresponding to the left and right front wheels and the left and right rear wheels.
The high master cylinder pressure P _{M / C} is introduced to all 22, 528 and 534. Therefore, if the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed under such a condition, the wheel cylinder pressure P _{W / C} of each wheel can be increased. Below, this state
(i) This is called pressure boost mode.

If both the holding solenoid S ** H and the pressure reducing solenoid S ** R are closed during execution of the ABS control, the wheel cylinder pressure P _{W / C} of each wheel can be held. . Hereinafter, this state is referred to as (ii) holding mode. Further, while the ABS control is being executed, the holding solenoid S ** H is closed and the pressure reducing solenoid S ** H is closed.
When R is opened, the wheel cylinder pressure P of each wheel is
_{W / C} can be depressurized. Below, this state is (iii)
It is called the decompression mode.

During execution of the ABS control, the ECU 10 appropriately performs the above (i) pressure increasing mode, (ii) holding mode, and
And (iii) the holding solenoid S ** H and the pressure reducing solenoid S ** R are controlled according to the slip state of each wheel so that the pressure reducing mode is realized. Holding solenoid S
When the ** H and the pressure reducing solenoid S ** R are controlled as described above, the wheel cylinder pressure P _{W / C of} all the wheels is controlled to an appropriate pressure that does not cause an excessive slip ratio on the corresponding wheels. To be done. Thus, according to the above control, the ABS function can be realized in the braking force control device.

When the pressure reducing mode is performed for each wheel during the execution of the ABS control, the brake fluid in the wheel cylinders 120 to 126 passes through the first pressure reducing passage 548 and the second pressure reducing passage 550 to the first reservoir 552. And flows into the second reservoir 554. The brake fluid that has flowed into the first reservoir 552 and the second reservoir 554 is
It is pumped up by the pump 560 and the second pump 562 and supplied to the hydraulic pressure passages 522 and 534.

A part of the brake fluid supplied to the hydraulic pressure passages 522 and 534 flows into the wheel cylinders 120 to 126 when (i) the pressure increasing mode is performed in each wheel. The rest of the brake fluid flows into the master cylinder 402 to make up for the outflow of the brake fluid.
Therefore, according to the system of this embodiment, the brake pedal 12 does not have an excessive stroke during the execution of the ABS control.

32 to 34 show the states of the braking force control device for realizing the BA function. The ECU 10
The BA function is realized by appropriately realizing the states shown in FIG. 32 to FIG. 34 after the brake operation for promptly raising the braking force by the driver, that is, the emergency brake operation is executed. Hereinafter, in the braking force control device, control for realizing the BA function is referred to as BA control.

FIG. 32 shows an assist pressure increasing state realized during execution of the BA control. The assist pressure increase state is B
When it is necessary to increase the wheel cylinder pressure P _{W / C} of each wheel during execution of A control, that is, during BA control
This is realized when execution of (I) start pressure increasing mode, (II) assist pressure increasing mode, and (V) assist pressure slowly increasing mode is requested.

In the system of the present embodiment, the assist pressure increasing state during the BA control is as shown in FIG. 32, the reservoir cut solenoids SRC _-1 504 and SRC _-2 50.
6, and master cut solenoid SMC- ₁ 512,
The SMC- ₂ 514 is turned on and the first pump 56
It is realized by turning on the 0 and the second pump 562.

When the assist pressure increasing state is realized during the execution of the BA control, the brake fluid stored in the reservoir tank 408 is pumped up to the first pump 560 and the second pump 562, and the hydraulic pressure passages 522, 534. Is supplied to. In the assist pressure increasing state, the hydraulic passage 522, the wheel cylinder 120 of the right front wheel FR and the wheel cylinder 126 of the left rear wheel RL are maintained in the conductive state. Further, in the assist pressure increasing state, the pressure on the hydraulic pressure passage 522 side exceeds the valve opening pressure of the constant pressure release valve 540 to exceed the master cylinder pressure P _{M / C.}
The flow of fluid from the hydraulic pressure passage 522 side toward the master cylinder 402 side is SMC _-1 until the pressure becomes higher than
Blocked by 512.

Similarly, in the assist pressure increasing state, the hydraulic pressure passage 534 and the wheel cylinder 122 of the left front wheel FL and the wheel cylinder 124 of the right rear wheel RR are maintained in the conductive state, and the hydraulic pressure passage 534 side Internal pressure is constant pressure release valve 54
The flow of fluid from the hydraulic pressure passage 534 side toward the master cylinder 402 side is blocked by the SMC _-2 514 until it exceeds the valve opening pressure of 2 and becomes higher than the master cylinder pressure P _{M / C.}

Therefore, when the assist pressure increasing state shown in FIG. 32 is realized, thereafter, the wheel cylinder pressure P _{W / C} of each wheel is set using the first pump 560 or the second pump 562 as a hydraulic pressure source. The pressure is quickly raised to a pressure exceeding the master cylinder pressure P _{M / C.} As described above, according to the assist pressure increasing state shown in FIG. 32, the braking force can be quickly raised.

By the way, in the assist pressure increasing state shown in FIG. 32, the hydraulic pressure passages 518, 522, 528, 530.
Is connected to the master cylinder 40 via the check valves 544 and 546.
It communicates with 2. Therefore, the master cylinder pressure P _{M / C}
If it is larger than the wheel cylinder pressure P _{W / C} of each wheel can boost the wheel cylinder pressure P _{W / C} as a fluid pressure source to the master cylinder 402. In BA operating state.

FIG. 33 shows an assist pressure holding state realized during execution of BA control. The assist pressure holding state is B
This is realized when it is necessary to maintain the wheel cylinder pressure P _{W / C} of each wheel during the execution of the A control, that is, when the (IV) assist pressure retention mode is required during the BA control. The assist pressure holding state is realized by turning on the master cut solenoids SMC- ₁ 512 and SMC- ₂ 514 as shown in FIG.

In the assist pressure holding state shown in FIG. 33, the first pump 560, the reservoir tank 408, and the second pump 560
The pump 562 and the reservoir tank 408 are SR
It is turned off by C _-1 504 and SRC _-2 506. Therefore, in the assist pressure holding state, the fluid pressure passages 522, 5 are discharged from the first pump 560 and the second pump 562.
Fluid is not discharged to 34. Further, in the assist pressure holding state shown in FIG. 33, the hydraulic pressure passages 518, 522 and 530, 534 have SMC _-1 512 and SM, respectively.
It is substantially decoupled from the master cylinder 402 by a C- ₂ 514. Therefore, according to the assist pressure holding state shown in FIG. 33, the wheel cylinder pressures P of all wheels are
_{W / C} can be kept constant.

FIG. 34 shows the assist pressure reducing state realized during execution of the BA control. The assist pressure reduction state is B
When it is necessary to reduce the wheel cylinder pressure P _{W / C} of each wheel during execution of A control, that is, during BA control (III)
It is realized when execution of the assist pressure reduction mode and (VI) assist pressure gentle reduction mode is requested. The assist pressure reducing state is realized by turning off all the solenoids as shown in FIG.

In the assist pressure reducing state shown in FIG. 34, first pump 560 and second pump 562 are separated from reservoir tank 408. Therefore, the first pump 56
2 and the second pump 562 to the hydraulic passages 522 and 534.
No fluid is discharged to the. Further, in the assist pressure reducing state, the wheel cylinders 120 to 126 of each wheel and the master cylinder 402 are in a conductive state. Therefore, when the assist pressure reducing state is realized, the wheel cylinder pressure P _{W / C} of all the wheels can be reduced with the master cylinder pressure P _{M / C} as the lower limit value.

In this embodiment, when the driver performs an emergency braking operation, the ECU 10 performs the assist pressure increasing state shown in FIGS. 32 to 34, as in the case of the first embodiment. The BA function is realized by combining the assist pressure holding state and the assist pressure reducing state.
Therefore, according to the braking force control device of the present embodiment, as in the case of the above-described first and second embodiments, when the driver performs the emergency braking operation, the driver's emergency braking operation is promptly performed. Generate the intended braking force, and
The driver's intention can always be reflected in the braking force during execution of the BA control.

In the braking force control system of the present embodiment, when the above-mentioned BA control is started, the wheel cylinder pressure P _{W / C of} each wheel is rapidly increased thereafter, so that any one of the wheels becomes excessive. Slip rate may occur. In such a case, the ECU 10 may use BA + ABS
Start control. The operation of the braking force control device associated with the BA + ABS control will be described below with reference to FIGS. 35 and 36 together with FIG. 34.

The braking force control system of this embodiment is BA + AB.
After the S control is started, the driver increases the braking force.
When the intended brake operation is performed, the ABS target wheel
Wheel cylinder pressure P_{W / C}The pressure required by the ABS control
Wheel cylinder pressure P of other wheels while controlling force_{W / C}of
Try to increase. FIG. 35 shows that the right rear wheel RL is the ABS target wheel.
Perform the above functions while executing BA + ABS control
State that will be realized (hereinafter, assist pressure increase (ABS)
(Referred to as a state). Assist pressure boost (ABS) state
Is the second reservoir cut solenoid SRC_-2506, oh
And master cut solenoid SMC_-1512, SMC
_-2514 is turned on and the first pump 560 and the second pump 560
Turns on the pump 562 and holds the right rear wheel RL
Solenoid SRLH110 and pressure reducing solenoid SRL
Controlling R118 as needed in response to ABS control requirements
Will be realized in.

In the assist pressure increasing (ABS) state,
Brake fluid discharged from the second pump 462 is supplied to the wheel cylinder 122 of the left front wheel FL and the wheel cylinder 124 of the right rear wheel RR, as in the assist pressure increasing state shown in FIG. Therefore, when the assist pressure increase (ABS) state is realized, the wheel cylinder pressure P _{W / C} of these wheels FL and RR is the same as when the assist pressure increase state is realized during BA control. Boosted.

BA + with the left rear wheel RL as the ABS target wheel
The ABS control is started by executing (ii) the pressure reducing mode for the left rear wheel RL. Therefore, the brake fluid flows into the first reservoir 552 at the same time when the BA + ABS control is started. In the assist pressure boosting (ABS) state shown in FIG. 35, the first pump 560 sucks the brake fluid that has thus flown into the first reservoir 552 and pumps it.

The brake fluid pumped by the first pump 560 is mainly the wheel cylinder 12 of the right front wheel FR.
It is supplied to the wheel cylinder 126 when (i) the pressure increasing mode is executed for the left rear wheel RL. According to the above control, the wheel cylinder pressure P _{W / C} of the right front wheel FR is increased in the same manner as when the assist pressure increasing state is realized during the BA control, and the wheel cylinder pressure P of the left rear wheel RL is increased. _{W / C} can be controlled to an appropriate value that does not cause an excessive slip ratio on the left rear wheel RL.

As described above, according to the assist pressure increase (ABS) state shown in FIG. 35, the wheel cylinder pressure P _{W / C} of the left rear wheel RL which is the ABS target wheel is set to the pressure corresponding to the ABS control request. While controlling, the wheel cylinder pressures P _{W / C} of the left and right front wheels FL, FR and the right rear wheel RR, which are non-target wheels of the ABS control, are swift as in the case where the assist pressure increasing state is realized during BA control. Can be boosted.

The braking force control system of this embodiment is BA + AB.
After the S control is started, when the driver performs a brake operation intended to maintain the braking force, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to a pressure according to the ABS control request, The wheel cylinder pressure P _{W / C} of other wheels is maintained. FIG. 36 is a state realized to fulfill the above function during execution of BA + ABS control in which the right rear wheel RL is the ABS target wheel (hereinafter, assist pressure holding (ABS)
(Referred to as a state). The assist pressure holding (ABS) state is the master cut solenoid SMC _-1 512, SMC _-2
514 is turned on, the first pump 560 and the second pump 562 are turned on, the holding solenoid SFRH104 of the right front wheel FR is turned on, and the holding solenoid SRLH110 and the pressure reducing solenoid S of the left rear wheel RL are turned on.
It is realized by appropriately controlling the RLR 118 according to a request for ABS control.

In the assist pressure holding (ABS) state,
The second pump 562 is shut off from the reservoir tank 408 as in the case where the assist pressure holding state shown in FIG. 33 is realized. Further, the hydraulic pressure passages 530 and 534 are substantially cut off from the master cylinder 402 as in the case where the assist pressure holding state shown in FIG. 33 is realized. Therefore, when the assist pressure holding (ABS) state is realized, the wheel cylinder pressure P of the left front wheel FL and the right rear wheel RR is increased.
_{W / C} is held at a constant value as in the case where the assist pressure holding state is realized during BA control.

At the same time as the assist pressure holding (ABS) state is realized or before the assist pressure holding (ABS) state is realized, the first reservoir 552 contains the brake fluid flowing out from the wheel cylinder 126. It can be stored. The first pump 560 holds the assist pressure (AB
While the state S) is realized, the brake fluid stored in the first reservoir 552 is sucked and pressure-fed.

The right front wheel FR in the assist pressure holding state
The wheel cylinder 120 of is separated from the first pump 560 by the SFRH 104. Therefore, the first
The brake fluid that is pumped by the pump 560 is
It is supplied only to the wheel cylinder 126 of the left rear wheel RL.
Further, the inflow of brake fluid from the first pump 560 to the wheel cylinder 126 is allowed only when the (i) pressure increasing mode is performed for the left rear wheel RL. According to the above-mentioned process, the wheel cylinder pressure P _{W / C} of the front right wheel FR is maintained at a constant value, the wheel cylinder pressure P _{W / C} of the rear left wheel RL is, an excessive slip rate in the front left wheel FL The pressure is controlled so that it will not be generated.

As described above, according to the assist pressure increase (ABS) state shown in FIG. 36, the wheel cylinder pressure P _{W / C} of the left rear wheel RL which is the ABS target wheel is set to an appropriate value in accordance with the ABS control request. While controlling the pressure, the wheel cylinder pressure P _{W / C} of the left and right front wheels FL, FR and the right rear wheel RR, which are non-target wheels of the ABS control, is the same as when the assist pressure holding state is realized during the BA control. It can be kept constant.

The braking force control system of this embodiment is BA + AB.
After the S control is started, when the driver performs a brake operation intended to reduce the braking force, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to a pressure according to the ABS control request, The wheel cylinder pressure P _{W / C} of the other wheels is reduced. The above-mentioned function realizes the assist pressure reducing state shown in FIG.
In order to realize (i) pressure increasing mode, (ii) holding mode, and (iii) pressure reducing mode in response to the ABS control request, the holding solenoid S ** H and the pressure reducing solenoid S ** R are appropriately used.
It is realized by controlling. Hereinafter, a state in which such control is executed is referred to as an assist pressure reduction (ABS) state.

That is, when the assist pressure reduction (ABS) state is realized, all the holding solenoids S ** H
Communicate with the master cylinder 402. Therefore, when the assist pressure reduction (ABS) control is realized, it is possible to reduce the wheel cylinder pressure P _{W / C} of the non-controlled target wheel of the ABS control with the master cylinder pressure P _{M / C} as the lower limit value.
Further, for the wheel subject to ABS control, the wheel cylinder pressure P _{W / C} can be held or reduced by implementing (ii) the holding mode and (iii) the pressure reducing mode.

By the way, the assist pressure reduction (ABS) state is used when the driver intends to reduce the braking force, that is, when it is not necessary to increase the wheel cylinder pressure P _{W / C of} any wheel. Will be realized. Therefore, if the (ii) holding mode and (iii) depressurization mode can be realized for the ABS target wheel as described above, the wheel cylinder pressure P _{W / C} of the ABS target wheel is appropriately controlled to the pressure required by the BA + ABS control. can do.

As described above, the assist pressure reduction (A
According to the (BS) state, while controlling the wheel cylinder pressure P _{W / C} of the ABS target wheel to an appropriate pressure according to the ABS control request, the right front wheel FR and the left and right rear wheels RL which are non-target wheels of the ABS control. , RR wheel cylinder pressure P _{W / C} to B
As in the case where the assist pressure reducing state is realized during the A control, the master cylinder pressure P _{M / C} can be reduced with the lower limit value.

As described above, according to the braking force control apparatus of the present embodiment, when the BA control is started and an excessive slip ratio occurs in any of the wheels, the wheel cylinder pressure P of the ABS target wheel is increased. _The ABS function of suppressing the _{W / C} to an appropriate pressure required by the ABS control and the wheel cylinder pressure P _{W / C} of the non-controlled target wheel of the ABS control are higher than the master cylinder pressure P _{M / C.} In the area, the BA function for increasing / decreasing according to the brake operation of the driver can be realized at the same time.

By the way, in the above-mentioned embodiment, the type of the braking force control device is limited to the hydro booster type and the pump up type, but the present invention is not limited to this, and the braking pedal force is doubled with respect to the brake pedal force. When a vacuum booster with a variable force ratio is used, it can be applied to a vacuum booster type braking force control device.

[0286]

As described above, according to the invention described in claim 1, the invention described in claim 2, and the invention described in claim 3, after the emergency braking operation is performed, the driver's intention is accurate. The braking force reflected in can be generated.
Further, according to the invention described in claim 4, it is possible to generate a substantially constant assist pressure with the execution of the emergency braking operation regardless of the level of the braking hydraulic pressure at the time when the pressure increase is started. Therefore, according to the present invention, it is possible to always generate a braking force that accurately reflects the driver's intention regardless of the level of the braking hydraulic pressure at the time of generation of the assist pressure.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a normal braking state of a braking force control device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a hydro booster used in the braking force control device shown in FIG.

FIG. 3 is a diagram showing an ABS operating state of the braking force control device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an assist pressure increasing state realized during BA control or BA + ABS control in the braking force control device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an assist pressure holding state realized during BA control or BA + ABS control in the braking force control device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an assist pressure reducing state realized during BA control or BA + ABS control in the braking force control device according to the first embodiment of the present invention.

FIG. 7A corresponds to the first embodiment of the present invention.
When an emergency braking operation is performed in the braking force control device
Master cylinder pressure P_{M / C}Change rate ΔP_{M / C}Not born
FIG. FIG. 7B shows the first embodiment of the present invention.
Emergency braking operation in the braking force control device corresponding to the example
Master cylinder pressure P_{M / C}And Hui
Cylinder pressure P _{W / C}It is a figure showing the change which arises in.

FIG. 8 is a flowchart of an example of a control routine executed to determine the establishment of the first standby state in the braking force control device according to the first embodiment of the present invention.

FIG. 9 is a flowchart of an example of a control routine executed to determine the establishment of the second standby state in the braking force control device according to the first embodiment of the present invention.

FIG. 10 is an example of a control routine that is executed by the braking force control apparatus according to the first embodiment of the present invention to determine whether the BA control start condition is satisfied and to calculate the pressure increase time in the start pressure increase mode. It is a flowchart of.

11 is an example of a map of a reference pressure increase time T _STA0 referred to in the control routine shown in FIG.

FIG. 12 is a flowchart (No. 1) of an example of a control routine executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 13 is a flowchart (No. 2) of an example of a control routine executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 14 is a flowchart (part 3) of an example of a control routine that is executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 15 is a flowchart (No. 4) of an example of a control routine executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 16 is a flowchart (No. 5) of an example of a control routine executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 17 is a flowchart (part 6) of an example of a control routine executed to realize BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 18 is a flowchart (No. 7) of an example of the control routine executed to realize the BA control in the braking force control device according to the first embodiment of the present invention.

FIG. 19 is a table showing a control mode executed subsequently to the start pressure increasing mode when the BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 20 is a table showing a control mode executed subsequently to the assist pressure increasing mode when BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 21 is a table showing a control mode executed subsequently to the assist pressure reduction mode when BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 22 is a table showing a control mode executed subsequently to the assist pressure holding mode when BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 23 is a table showing a control mode executed subsequently to the assist pressure moderate increase mode when BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 24 is a table showing a control mode that is executed subsequently to the assist pressure gradual decrease mode when BA control is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 25 is a system configuration diagram showing a normal braking state and an ABS operating state of the braking force control device according to the second embodiment of the present invention.

FIG. 26 is a diagram showing an assist pressure increasing state realized during BA control in the braking force control device according to the second embodiment of the present invention.

FIG. 27 is a diagram showing an assist pressure holding state realized during BA control in the braking force control device according to the second embodiment of the present invention.

FIG. 28 is a diagram showing an assist pressure reducing state realized during BA control or BA + ABS control in the braking force control device according to the second embodiment of the present invention.

FIG. 29 is a diagram showing an assist pressure increasing state realized during BA + ABS control in the braking force control device according to the second embodiment of the present invention.

FIG. 30 is a diagram showing an assist pressure holding state realized during BA + ABS control in the braking force control device according to the second embodiment of the present invention.

FIG. 31 is a system configuration diagram showing a normal braking state and an ABS operating state of the braking force control device according to the third embodiment of the present invention.

FIG. 32 is a diagram showing an assist pressure increasing state realized during BA control in a braking force control device corresponding to a third example of the present invention.

FIG. 33 is a diagram showing an assist pressure holding state realized during BA control in a braking force control device corresponding to a third example of the present invention.

FIG. 34 is a diagram showing an assist pressure reducing state realized during BA control or BA + ABS control in the braking force control device according to the third embodiment of the present invention.

FIG. 35 is a diagram showing an assist pressure increasing state realized during BA + ABS control in a braking force control device corresponding to a third example of the present invention.

FIG. 36 is a diagram showing an assist pressure holding state realized during BA + ABS control in the braking force control device according to the third embodiment of the present invention.

[Explanation of symbols]

10 Electronic Control Unit (ECU) 12 Brake Pedal 36 Hydro Booster 86 First Assist Solenoid (SA _-1 ) 88 Second Assist Solenoid (SA _-2 ) 90 Third Assist Solenoid (SA _-3 ) 94 Regulator Switching Solenoid (STR) 104, 106, 108, 110 Holding solenoid (S
** H) 112, 114, 116, 118 Pressure reducing solenoid (S
** R) 120, 122, 124, 126 Wheel cylinder 144 Fluid pressure sensor 400 Vacuum booster 402 Master cylinder 414 Front reservoir cut solenoid (SRC)
F) 416 Rear reservoir cut solenoid (SRCR) 426 Right front master cut solenoid (SMFR) 428 Left front master cut solenoid (SMFL) 430 Rear master cut solenoid (SMR) 460 Front pump 462 Rear pump 504 First reservoir cut solenoid (SRC _-1 ) 506 Second reservoir cut solenoid (SRC _-2 ) 512 First master cut solenoid (SMC _-1 ) 514 Second master cut solenoid (SMC _-2 ) 560 First pump 562 Second pump

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-61-268560 (JP, A) JP-A-9-30394 (JP, A) JP-A-9-39755 (JP, A) JP-A-8- 324420 (JP, A) JP 8-230648 (JP, A) JP 61-139546 (JP, A) JP 4-121260 (JP, A) JP 7-165038 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T 8/00-8/96

Claims (4)

(57) [Claims] 1. An emergency braking operation is performed by a driver.
Generates a larger braking hydraulic pressure than normal during
In the braking force control device, An operation speed detecting means for detecting a brake operation speed, The aboveDetected by operation speed detection meansBrake operation
Emergency detecting execution of emergency braking operation based on speed
Brake operation detection means,Brake operation detected by the operation speed detecting means
When the speed falls within the specified range, the braking force control device
To the standby state, The braking force control device is in the standby state, and
By the emergency braking operation detecting means Emergency braking
Occurred in the process of emergency braking when a motion was detected
Only the assist pressure corresponding to the brake operation speed is
Braking oil pressure increasing means for generating a large braking oil pressure, A braking force control device comprising: 2. The braking force control device according to claim 1, wherein the braking hydraulic pressure increasing means increases the braking hydraulic pressure at a predetermined change rate regardless of whether or not a brake operation is performed, and an emergency brake. When an operation is detected, an assist time control means for increasing the braking hydraulic pressure by the first assist pressure generating means for a pressure increase time corresponding to the brake operation speed generated in the process of the emergency brake operation. A characteristic braking force control device. 3. The braking force control device according to claim 1, wherein the braking hydraulic pressure increasing means detects a second assist pressure generating means for increasing the braking hydraulic pressure regardless of whether or not a braking operation is performed, and an emergency braking operation is detected. At that time, with a pressure increase gradient according to the brake operation speed generated in the process of emergency brake operation,
A braking force control device, comprising: an assist gradient control means for increasing the braking hydraulic pressure by the second assist pressure generating means for a predetermined pressure increase time. 4. The braking force control device according to claim 2, wherein the first assist pressure generating means includes an accumulator that stores a predetermined hydraulic pressure as a hydraulic pressure source of the assist pressure, and the first assist pressure generating means. A braking force control device comprising: a pressure increasing time correction means for correcting the pressure increasing time by the first assist pressure generating means based on the braking oil pressure when the pressure increasing of the braking oil pressure is started.