JP2002002466A - Brake system, method of detecting load condition, and method of controlling fluid pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain change of a relation between a brake operation amount by a drivewr and decelerations before and after front and rear braking force distribution control is started, so as to reduce unfamiliar feeling for the driver. SOLUTION: In the front and rear braking force distribution control, brake fluid pressure of rear wheels is restrained with respect to fluid pressure of a pressure device although brake fluid pressure of front wheels is brought to a level same to the fluid pressure of the pressure device. A ratio of the rear wheel brake fluid pressure to the front wheel brake fluid pressure is controlled to be brought close to a value expressed by an ideal braking force distribution line. Since the fluid pressure of the rear wheel is restrained with respect to the fluid pressure of the pressure device, the relation between the brake operation amount by the driver and the decelerations is changed before and after the front and rear braking force distribution control is started. As to this point, the fluid pressure of the pressure device is increased in accompaniment to the start of the front and rear braking force distribution control to reduce the unfamiliar feeling for the driver before and after the control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake device.

[0002]

2. Description of the Related Art JP-A-10-310044 discloses that
A master cylinder as a pressurizing device, a plurality of control valve devices respectively provided between the master cylinder and the front and rear wheel brake cylinders, and a master cylinder and a rear wheel brake cylinder of the control valve devices. There is described a brake device including an individual hydraulic pressure control device that reduces the hydraulic pressure of a brake cylinder of a rear wheel with respect to the hydraulic pressure of a master cylinder by controlling an intervening one. In this brake device, the front and rear braking force distribution control is performed in which the hydraulic pressure of the rear wheel brake cylinder is suppressed with respect to the hydraulic pressure of the front wheel brake cylinder under the control of the individual hydraulic pressure control device. As a result, the braking force obtained from the road surface of the vehicle can be used to the maximum. However, when the hydraulic pressure of the rear wheel brake cylinder is suppressed, before and after the suppression of the hydraulic pressure of the rear wheel brake cylinder,
Since the relationship between the brake operation amount such as the operation stroke and the operation force of the brake operation member by the driver and the vehicle deceleration changes, the driver may feel uncomfortable.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problem of the driver when the hydraulic pressure of at least one brake cylinder is controlled to be lower than the hydraulic pressure of the pressurizing device. The purpose is to reduce discomfort. The above object is attained by providing the brake device having the following configurations. Each aspect is, like the claims, divided into sections, and each section is numbered,
Enter the number of another section as necessary.
This is to facilitate understanding of the present invention, and the technical features and combinations thereof described in this specification should not be construed as being limited to the following sections. Also, 1
If more than one item is listed in a section, it is not always necessary to adopt all items together, but it is also possible to extract and adopt only some items. (1) A pressurizing device capable of controlling the hydraulic pressure while pressurizing the hydraulic fluid, and a fluid of a brake cylinder corresponding to itself provided between the pressurizing device and at least one of the plurality of brake cylinders. A plurality of control valve devices for controlling the pressure, and by controlling at least one of the plurality of control valve devices, the hydraulic pressure of the brake cylinder corresponding to the control valve device is adjusted with respect to the hydraulic pressure of the pressurizing device. A brake device comprising: an individual hydraulic pressure control device that suppresses pressure by a pressure control device; and a pressurizing device control device that increases the hydraulic pressure of the pressurizing device with the start of control by the individual hydraulic pressure control device. Item 1). In the brake device described in this section,
With the start of the suppression control by the individual hydraulic control device, the hydraulic pressure of the pressurizing device is increased. The hydraulic pressure of the pressurizing device is increased from the hydraulic pressure when the suppression control by the individual hydraulic pressure control device is not performed, whereby the amount of brake operation by the driver and the vehicle deceleration before and after the suppression control are reduced. Can be suppressed, and the driver's discomfort can be reduced. The control valve device may be provided corresponding to one brake cylinder, or may be provided commonly to two or more brake cylinders. Anti-lock control, front-rear braking force distribution control, left-right braking force distribution control, vehicle stability control during braking, and the like correspond to the control by the individual hydraulic pressure control device. Although it can be applied, it is preferable to be applied in a control in which a driver's discomfort caused by performing these controls becomes a problem. For example, front and rear braking force distribution control,
If the hydraulic pressure of the pressurizing device is increased with the start of the left / right braking force distribution control, the vehicle stability control during braking, and the like, it is possible to reduce the driver's discomfort due to these controls, which is effective and effective. is there. (2) the pressurizing device comprises: (a) a master cylinder for generating a hydraulic pressure in accordance with an input applied to a pressurizing piston;
A hydraulic booster that boosts the input applied to the power piston using the hydraulic pressure of the power hydraulic pressure source and outputs the boosted piston to the pressurizing piston; (c) the hydraulic booster and the power hydraulic pressure source And the electromagnetic pressure control valve provided between the pressure control device and the pressurizing device control device controls the hydraulic pressure of the pressurizing device by controlling the electromagnetic hydraulic pressure control valve (1). The brake device according to item 1. If the electromagnetic hydraulic pressure control valve is controlled, the hydraulic pressure of the hydraulic booster is controlled. The boost factor of the input applied to the power piston (for example, often has a magnitude corresponding to the braking force by the driver) is controlled, and the hydraulic pressure of the pressurizing chamber of the master cylinder when the braking force is the same That is, the hydraulic pressure of the pressurizing device is controlled. Note that the pressurizing device may not include the electromagnetic hydraulic pressure control valve. For example, when the power type hydraulic pressure source includes a pump for pressurizing the hydraulic fluid and a pump motor for driving the pump, the hydraulic pressure of the hydraulic fluid discharged from the pump is controlled by controlling the pump motor. Thus, the hydraulic pressure of the hydraulic booster can be controlled. (3) The pressurizing device comprises: (a) a master cylinder for generating a hydraulic pressure in accordance with an input applied to a pressurizing piston;
A pressure booster that increases and outputs the hydraulic pressure of the master cylinder using the hydraulic pressure of the power hydraulic pressure source, and (c) provided between the pressure booster and the power hydraulic pressure source. The brake device according to (1), wherein the brake control device controls the hydraulic pressure of the pressurizing device by controlling the electromagnetic hydraulic pressure control valve. . (4) the pressurizing device: (a) a power type hydraulic pressure source that pressurizes and outputs hydraulic fluid with power, and (b) an electromagnetic hydraulic pressure control valve capable of controlling the hydraulic pressure of the power type hydraulic pressure source. The brake device according to claim 1, wherein the pressurizing device control device controls the hydraulic pressure of the pressurizing device by controlling the electromagnetic hydraulic pressure control valve device. The pressurizing device may not include the master cylinder. In this case, the hydraulic pressure of the pressurizing device can be controlled to a height corresponding to the brake operating force by controlling the electromagnetic hydraulic pressure control valve. The pressurizing device may include an accumulator. (5) Before and after the individual hydraulic pressure control device controls the hydraulic pressure of the rear wheel brake cylinder with respect to the hydraulic pressure of the front wheel brake cylinder by controlling a control valve device corresponding to the rear wheel brake cylinder. Including braking force distribution control unit (1)
The brake device according to any one of paragraphs (4) to (4).
In the front-rear braking force distribution control, the hydraulic pressure of the rear wheel brake cylinder is suppressed with respect to the hydraulic pressure of the pressurizing device, and the hydraulic pressure of the pressurizing device is transmitted to the front wheel brake cylinder without being suppressed. As a result, the hydraulic pressure of the rear wheel brake cylinder is suppressed with respect to the hydraulic pressure of the front wheel brake cylinder. In the brake device described in this section, the hydraulic pressure of the pressurizing device is increased with the start of the suppression of the hydraulic pressure of the brake cylinder of the rear wheel, and the hydraulic pressure of the brake cylinder of the front wheel is increased. (6) The pressurizing device control device includes a loading state corresponding control unit that controls a hydraulic pressure of the pressurizing device based on a loading state of the vehicle. The brake device according to claim (Claim 2). In the brake device described in this section, the hydraulic pressure of the pressurizing device is controlled based on the loaded state. Therefore, the difference in the relationship between the amount of brake operation by the driver and the deceleration caused by the different loading states can be reduced, and the driver's discomfort can be reduced. (7) The brake device includes a loading state detection device that detects a loading state of the vehicle, and the individual hydraulic pressure control device and the pressurizing device control device, based on the loading state detected by the loading state detection device. The brake device according to any one of (1) to (6), wherein at least one of the brake devices controls at least one of the control valve device and the pressurizing device. In the brake device described in this section, the control of the control valve device by the individual hydraulic pressure control device and the control of the pressurizing device by the pressurizing device control device are controlled based on the loading state detected by the loading state detection device. . The loading state detection device may detect the loading state of the vehicle in a stepwise manner or may continuously detect the loading state of the vehicle. Examples of the device that detects in a stepwise manner include a device that detects whether the vehicle is in a constant load state or a light load state, and a device that detects the load state in three or more stages. In addition, a device that continuously detects the loaded weight of the vehicle corresponds to the continuous detection device. The loaded weight of the vehicle can be detected, for example, based on the load applied to each wheel. (8) From the timing determined by the individual hydraulic pressure control device based on the loaded state of the vehicle detected by the loaded state detection device, the hydraulic pressure of the brake cylinder of the rear wheel is adjusted with respect to the hydraulic pressure of the pressurizing device. The brake device according to the mode (7), wherein the braking force distribution control before and after the control is started. The ideal braking force distribution line differs between a case where the vehicle is in a constant loading state and a case where the vehicle is in a light loading state. In order to bring the ratio between the front wheel braking force and the rear wheel braking force closer to the value represented by the ideal braking force distribution line in each of the case of the constant load state and the case of the light load state, The break point is determined based on the loading state detected by the loading state detection device,
It is desirable that the brake cylinder fluid pressure of the rear wheel be suppressed with respect to the brake cylinder fluid pressure of the front wheel from the time when the break point is reached. The front-rear braking force distribution control may be started from a timing when the master cylinder pressure reaches the hydraulic pressure corresponding to the break point, or may be started from a timing when the vehicle deceleration reaches the deceleration corresponding to the break point. Or you can. (9) The brake according to (7) or (8), wherein the pressurizing device control device starts control of the pressurizing device from a timing determined based on the loading state detected by the loading state detecting device. apparatus. If the control of the pressurizing device is started from a state in which the brake fluid pressure is smaller than in the case where the vehicle is in the constant load state and the case where the vehicle is in the light load state, the driver may feel uncomfortable. Can be reduced in many cases. The control start timing of the pressurizing device may be determined stepwise according to the loading state, or may be determined continuously. (10) The pressurizing device control device controls the hydraulic pressure of the pressurizing device to a height determined based on the loading state detected by the loading state detecting device (7) to (9). The brake device according to any one of the above. When it is said that it is in a fixed loading state, it is considered that it is in a light loading state,
If the hydraulic pressure of the pressurizing device is increased and the hydraulic pressure of the brake cylinder is increased, the driver's uncomfortable feeling can be reduced between a constant load state and a light load state. For example, when the target hydraulic pressure of the pressurizing device is determined based on the brake operation state, the determination may be made in consideration of the loaded state. When the brake operation state is the same, the target hydraulic pressure is determined to be a higher value in the constant load state than in the light load state. (11) the pressurizing device, wherein the pump pressurizes the working fluid;
A linear hydraulic pressure control valve capable of controlling the hydraulic pressure of the hydraulic fluid discharged from the pump to a height corresponding to the supply current, wherein the pressurizing device control device controls the supply current to the linear hydraulic pressure control valve. Includes a supply current control unit that controls based on the loading state of the vehicle detected by the loading state detection device (7)
The brake device according to any one of paragraphs (10) to (10).
If the supply current to the linear hydraulic pressure control valve is controlled based on the loaded state, the hydraulic pressure of the pressurizing device can be controlled to a height based on the loaded state. (12) The vehicle loaded state detecting device detects the loaded state of the vehicle based on the slip state of the front wheels and the slip state of the rear wheels in a state where the control by the individual hydraulic pressure control device is not performed (7). The brake device according to any one of paragraphs (11) to (11). The loading state can be detected based on the slip state of the front wheels and the slip state of the rear wheels when the control by the individual hydraulic pressure control device is not performed. For example, as shown in FIG. 10, before the front-rear braking force distribution control is performed, the slip ratio of each wheel is smaller in the constant load state than in the light load state. In addition, the load applied to each wheel is larger in the constant load state than in the light load state, but since the position of the center of gravity usually moves to the rear wheel side, the amount of increase in the load applied to the rear wheel Becomes larger than the increase in the load applied to the front wheels. As a result, the ratio of the rear wheel slip ratio to the front wheel slip ratio (SR / SF) is smaller in the constant load state than in the light load state. By utilizing these facts, it is possible to detect the loaded state of the vehicle based on the slip state of the front wheels and the slip state of the rear wheels in a state where the control by the individual hydraulic pressure control device is not performed. (13) The brake device according to (12), wherein the loaded state detection device detects a loaded state of the vehicle based on a ratio between the slip ratio of the front wheels and the slip ratio of the rear wheels. (14) A pressurizing device capable of controlling the hydraulic pressure while pressurizing the hydraulic fluid, a brake cylinder connected to the pressurizing device, and a loaded state for detecting a loaded state of a vehicle equipped with the brake device. A brake device comprising: a detecting device; and a pressurizing device control device that controls the pressurizing device based on the loaded state detected by the loaded state detecting device (Claim 3). The technical features described in any of the above items (1) to (13) can be adopted in the brake device described in this item. (15) The hydraulic pressure of the brake cylinder is lower when the pressure controller is detected by the loading state detector to be in the constant loading state than when it is detected to be in the light loading state. Start control of the pressurizing device
The brake device according to (14). (16) The pressurizing device controller increases the hydraulic pressure of the brake cylinder when the loading state detection device detects that the vehicle is in the constant loading state, compared to when it is detected that the vehicle is in the lightly loaded state ( The brake device according to the above (14) or (15). (17) A pressurizing device that pressurizes the hydraulic fluid and that can control the fluid pressure, and a fluid of the brake cylinder corresponding to itself provided between the pressurizing device and at least one of the plurality of brake cylinders. A plurality of control valve devices for controlling the pressure, and by controlling at least one of the plurality of control valve devices, the hydraulic pressure of the brake cylinder corresponding to the control valve device is adjusted with respect to the hydraulic pressure of the pressurizing device. Individual pressure control device, and a pressure device control device that controls the pressure of the pressure device in a different manner before and after the control by the individual pressure control device is started. A brake device characterized by the following. For example, in a case where the output hydraulic pressure of the pressurizing device is controlled to a height at which the operating force of the brake operating member is boosted at a constant boost factor, the boost factor is set to a different value before and after the start. Controls to be performed. In this case, if the boost factor is increased after the start, compared to before the start, the hydraulic pressure of the pressurizing device is increased, and the driver's discomfort caused by the control by the individual hydraulic pressure control device is reduced. be able to. The technical features described in any of the above modes (1) to (16) can be adopted in the brake device described in this mode. (18) A loading that detects the loading state of the vehicle based on the slip state of the front wheels and the slip state of the rear wheels when the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are substantially the same. State detection method. (19) The loading according to (18), wherein the detection of the loading state of the vehicle is performed in a state where the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are at a predetermined height. State detection method (claim 4). (20) A loading that detects the loading state of the vehicle based on the slip state of the front wheel and the slip state of the rear wheel when the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are substantially the same. A state detecting step, and a loading state corresponding hydraulic control step of controlling a hydraulic pressure of at least one of the front wheel and the rear wheel brake cylinders based on the loading state of the vehicle detected in the loading state detection step. Pressure control method. (21) The hydraulic pressure according to (20), wherein the loaded state detecting step is performed in a state where the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are at a predetermined height. Control method (Claim 5).

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a brake device according to an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 10 denotes a brake pedal as a brake operating member. The brake pedal 10 is connected to a master cylinder 14 via a vacuum booster (hereinafter simply referred to as a booster) 12. The master cylinder 14 is of a tandem type, and two pressurizing pistons are slidably fitted in series with each other in the housing, so that two pressurizing chambers are formed independently of each other in front of each pressurizing piston. ing. The master cylinder 14 mechanically generates a hydraulic pressure equal in height to each of the two pressurizing chambers in accordance with a brake operation force which is a depression force of the brake pedal 10. The brake device in the present embodiment is of a two-system type.

[0005] The booster 12 is well known and will not be described in detail. However, the booster 12 is connected to a negative pressure chamber connected to a surge tank (the intake side of the combustion chamber) of the engine and the brake pedal 10. And a variable pressure chamber selectively connected to the negative pressure chamber and the atmosphere. The differential pressure between these chambers assists the operating force and outputs it to the master cylinder 14.

In one pressurizing chamber of the master cylinder 14,
A brake cylinder 56 for operating the brakes 54 of the left and right front wheels 52 is connected.
The brake cylinder 60 for operating the brake 58 is connected. In the hydraulic system on the front wheel side, the master cylinder 14 and the brake cylinders 56 of the left and right front wheels 52 are provided.
Are connected by a main liquid passage 64. The main liquid passage 64 is branched in a forked shape after extending from the master cylinder 14, and one main passage 66 and two branch passages 68 are connected to each other. A pressure control valve 70 is provided in the middle of the main passage 66, and the above-described brake cylinder 56 is connected to the tip of each branch passage 68. The pressure control valve 70 in the main liquid passage 64
A pump passage 7 is provided between the pump cylinder 7 and the brake cylinder 56.
2 is connected, and a pump 74 is
Is provided. The pump 74 is driven by a pump motor 76.

In FIG. 2, a pressure control valve 70 controls the communication between the master cylinder 14 and the brake cylinder 56, and electromagnetically controls the pressure difference between them. . The pressure control valve 70 includes a housing (not shown), a valve element 80, a valve seat 82 on which the valve element 80 is to be seated, and a coil 84 that generates a magnetic force for controlling the relative movement of the valve element 80 and the valve seat 82. In a non-operating state (OFF state) where the coil 84 is not excited, the valve 80 is moved by the elastic force of the spring 86 to the valve seat 8.
2 apart. Thereby, the main liquid passage 64
In this case, a bidirectional flow of the hydraulic fluid between the master cylinder side and the brake cylinder side is allowed. When the brake operation is performed, the hydraulic pressure of the brake cylinder 56 is changed as the hydraulic pressure of the master cylinder 14 increases, and these hydraulic pressures have the same magnitude. As long as the coil 84 is not energized, the valve element 80 does not sit on the valve seat 82 even if the master cylinder hydraulic pressure, that is, the brake cylinder hydraulic pressure increases. The pressure control valve 70 is a normally open valve.

On the other hand, in the operation state (ON state) in which the coil 84 is excited, the armature 88 is attracted by the magnetic force of the coil 84, and the valve 80 that moves integrally with the armature 88 is attached to the valve seat 82. You can be seated. At this time, the valve 80 has a sum of the attractive force F1 based on the magnetic force of the coil 84, the differential pressure acting force F2 based on the difference between the brake cylinder hydraulic pressure and the master cylinder hydraulic pressure, and the elastic force F3 of the spring 86. Act in opposite directions to each other. In a region where the suction force F1 is large with respect to the differential pressure acting force F2 based on the difference between the brake cylinder hydraulic pressure and the master cylinder hydraulic pressure and the equation F2 ≦ F1−F3 is satisfied, the valve element 80 is seated on the valve seat 82. Thus, outflow of the hydraulic fluid from the brake cylinder 56 is prevented.
By supplying high-pressure hydraulic fluid from the pump 74,
The hydraulic pressure of the brake cylinder 56 is increased, and can be higher than the hydraulic pressure of the master cylinder 14.

When the differential pressure acting force F2 increases with the increase of the brake cylinder hydraulic pressure and the expression F2> F1-F3 is satisfied, the valve element 80 is separated from the valve seat 82. The hydraulic fluid in the brake cylinder 56 is the master cylinder 1
The pressure is returned to 4 and the pressure is reduced. If the elastic force F3 is neglected in these equations, the brake cylinder hydraulic pressure is controlled to be higher than the master cylinder hydraulic pressure by the differential pressure based on the coil attraction force F1. Also, the relative position of the valve element 80 with respect to the valve seat 82 is determined by the differential pressure acting force, the suction force,
Since it is determined by the elastic force, the distance between them, that is, the opening degree can be controlled by controlling the suction force. The magnitude of the attractive force F1, which is the magnetic force of the coil 84, is designed to change linearly in accordance with the magnitude of the exciting current I of the coil 84.

As shown in FIG. 1, the pressure control valve 70 is provided with a bypass passage 92, and a bypass valve 94 is provided in the middle of the bypass passage 92 as a check valve. Even if the pressure control valve 70 is closed by the fluid force generated in the movable member in the pressure control valve 70 when the brake pedal 10 is depressed, or the pressure control valve 70 is mechanically closed, The flow of the hydraulic fluid from the master cylinder 14 to the brake cylinder 56 is ensured.

A holding valve 100, which is a normally open electromagnetic on-off valve, is provided at a portion of each branch passage 68 closer to the brake cylinder than a connection point with the pump passage 72. Holding valve 100
In this state, the coil 101 (see FIG. 3) is excited to be closed, and in this state, the brake cylinder 56, the master cylinder 14, and the pump 74 are shut off, whereby the brake cylinder fluid pressure is maintained. A bypass passage 102 is connected to each holding valve 100, and each bypass passage 102
Is provided with a bypass valve 104 for returning hydraulic fluid as a check valve. The reservoir passage 1 extends from a portion of each branch passage 68 between the holding valve 100 and the brake cylinder 56.
06 extends to the reservoir 108. In the middle of each reservoir passage 106, a pressure reducing valve 1 which is a normally closed electromagnetic on-off valve
10 are provided. The pressure reducing valve 110 includes a coil 112
Is excited to be in an open state. In this state, the flow of the hydraulic fluid from the brake cylinder 56 to the reservoir 108 is permitted, and the hydraulic pressure of the brake cylinder is reduced.

The reservoir 108 is configured such that a reservoir piston is substantially airtightly and slidably fitted to the housing, and the fitting urges the hydraulic fluid in a reservoir chamber formed in front of the reservoir piston. It is housed under pressure by a spring as a means. The reservoir chamber is connected to the main liquid passage 64 by the pump passage 72. In the pump passage 72, in addition to the above-described pump 74, a suction valve 124, a discharge valve 126, a damper 128, and the like, which are check valves, are provided. Damper room 1
The pulsation of the pump 74 is reduced by 28 and the like.

A portion of the pump passage 72 between the suction valve 124 and the reservoir 108 is connected by a supply passage 130 to a portion of the main liquid passage 64 between the master cylinder 14 and the pressure control valve 70. In the middle of the supply passage 130, an inflow control valve 132 is provided. Inflow control valve 1
Reference numeral 32 denotes a normally-closed electromagnetic on-off valve, which is switched from a closed state (supply blocking state) to an open state (supply state) when the coil 133 is excited. A check valve 134 is provided at a portion of the pump passage 72 between the connection point with the supply passage 130 and the reservoir 108. This check valve 13
Numeral 4 is provided to prevent the hydraulic fluid from the master cylinder 14 from flowing into the reservoir 108 when the inflow control valve 132 is in the open state. It is sucked into the pump 74 as it is. The reservoir passage 106 is connected to the pump passage 72 between the check valve 134 and the reservoir 108.

As described above, the master cylinder 14 is connected to the suction side of the pump 74 via the supply passage 130. The hydraulic fluid of the master cylinder 14 is supplied through the supply passage 130, pressurized by the pump 74, and supplied to the brake cylinder 56. When the hydraulic pressure of the brake cylinder 56 is controlled to be higher than the hydraulic pressure of the master cylinder 14, if the hydraulic fluid of the master cylinder 14 is supplied to the pump 74, the hydraulic fluid of the reservoir is supplied. When controlling the hydraulic pressure of the brake cylinder 56 to the same height, the energy consumption of the pump 74 can be reduced. Note that the configuration of the hydraulic system on the rear wheel side is the same as the configuration of the hydraulic system on the front wheel side, and a description thereof will be omitted.

In this embodiment, the booster 12, the master cylinder 14, the pressure control valve 70, the pump 74, the pump motor 76, the supply passage 130, the inflow control valve 132, etc. constitute a pressurizing device 150. The pressurizing device 150 includes a pressure increasing device for increasing the output hydraulic pressure of the master cylinder 14. The pressure increasing device includes a pressure control valve 70, a pump 74, a pump motor 76, a supply passage 130, an inflow control valve 132, and the like. Be composed. The inflow control valve 132 is opened when the pressure increasing device operates. Holding valves 1 provided corresponding to each of the brake cylinders 56 of the left and right front wheels 52
00, the control valve device 15 on the front wheel side by the pressure reducing valve 110 and the like.
2 and the holding valve 100 and the pressure reducing valve 1 provided corresponding to each of the brake cylinders 60 of the left and right rear wheels 57.
The rear wheel side control valve device 154 is constituted by 10 and the like.

The hardware configuration of the brake device has been described above. Next, the software configuration will be described with reference to FIG. This brake device includes a hydraulic pressure control device 180 mainly composed of a computer. The hydraulic pressure control device 180 includes a CPU 182, a ROM 184, a RAM 18
6, a computer including an input unit 188, an output unit 190, and the like.
A braking force distribution control routine shown in the flowchart of FIG. 4, a loading state determination routine shown in the flowchart of FIG. 5, and the like are stored.
The process is executed by the U182 using the RAM 186.

The input unit 188 of the hydraulic pressure control device 180 includes:
Brake switch 200, master cylinder pressure sensor 2
02, wheel speed sensor 204, front wheel brake fluid pressure sensor 2
06, a rear wheel brake fluid pressure sensor 208, an output fluid pressure sensor 210, a front and rear G sensor 212, and the like are connected. The master cylinder hydraulic pressure sensor 202 detects the hydraulic pressure in the pressurizing chamber of the master cylinder 14, but since the master cylinder pressure has a height corresponding to the brake operating force, in the present embodiment, the master cylinder A brake operation force is detected based on the pressure. The output hydraulic pressure sensor 210 detects the output hydraulic pressure of the pressurizing device 150, and detects the hydraulic pressure obtained by adding the master cylinder pressure and the assist pressure. The wheel speed sensor 204 is provided for each wheel and outputs a wheel speed signal of each wheel. A slip state or the like is obtained based on the wheel speed of each wheel.

On the other hand, the output unit 190 of the hydraulic pressure control device 180
Is connected to a pump motor 76 via a drive circuit (not shown). The pump motor 76 is controlled according to a control signal from the hydraulic pressure control device 180 to the drive circuit. The output unit 190 is connected to the solenoid 84 of the pressure control valve 70, the holding valve 100, the pressure reducing valve 110, and the solenoids 101, 112, and 133 of the inflow control valve 132 via a drive circuit. A current corresponding to the command value is supplied to the solenoid 84 of the pressure control valve 70, and the holding valve 100, the pressure reducing valve 11
0, solenoids 101, 112, 1 of the inflow control valve 132
The supply current to 33 is ON / OFF controlled.

The operation of the brake device will be described. When the brake pedal 10 is operated, a hydraulic pressure is generated in the master cylinder 14 in accordance with the operation, and the brake 54,
58 is activated. When a predetermined condition is satisfied during the operation of the brake, the brake assist control is performed by controlling the pressure control valve 70. The brake fluid pressure is higher than the pressure of the master cylinder 14 by the pressure control valve 70.
Is increased by the differential pressure corresponding to the supply current to the power supply. In the present embodiment, the target hydraulic pressure P _A ^* of the pressurizing device 150 is determined to a magnitude at which deceleration according to the brake operating force, that is, the master cylinder pressure is obtained.
The output pressure of to approach the target hydraulic pressure P _A ^*, the amount of current supplied to the solenoid 84 of the pressure control valve 70 is determined. As the amount of current supplied to the solenoid 84 increases, the assist pressure increases, and the hydraulic pressure of the pressurizing device 150 increases when the master cylinder pressure is the same. In the present embodiment, in the brake assist control, the current supplied to the pressure control valve 70 is made equal between the front wheel side and the rear wheel side.

In this embodiment, the brake assist control is performed based on the loaded state. The start time of the brake assist control is determined based on the loaded state. When it is determined that the vehicle is in the constant load state, the operation is started from a state in which the brake operation force is smaller (a state in which the master cylinder pressure is smaller) than in the case where the vehicle is in the light load state. In the present embodiment, when it is determined that the vehicle is in the constant loading state,
When the master pressure PM starts to reach the assist control start pressure PMth (hereinafter, simply referred to as start pressure PMth) and is determined to be in the lightly loaded state, the booster 12
Is started from the earlier of when the vehicle reaches the assisting limit and when the longitudinal braking force distribution control is started. Hereinafter, the description will be given on the assumption that the front-rear braking force distribution control is started before the booster 12 reaches the assisting limit in the lightly loaded state. Also, the target hydraulic pressure P _A ^{* of the} pressurizing device 150
Is determined based on the loading state. It is determined that the assist pressure when the brake operation force is the same when the vehicle is in the constant load state is higher than when the brake operation force is the same when the vehicle is in the light load state.

Further, longitudinal braking force distribution control is performed.
The brake fluid pressure of the rear wheel 57 is suppressed with respect to the brake fluid pressure of the front wheel 52, so that the front wheel 52 and the rear wheel 57 can be locked at the same time, and the vehicle is moved from the road surface. The received braking force can be maximized. In the present embodiment, the holding valve 100,
By controlling the opening and closing of the pressure reducing valve 110, the brake fluid pressure of the rear wheel 57 is suppressed with respect to the output fluid pressure of the pressurizing device 150, whereas the holding valve 100 on the front wheel side is kept open. The brake hydraulic pressure of the front wheels 52 is set to be substantially the same as the output hydraulic pressure of the pressurizing device 150. As a result, the brake fluid pressure of the rear wheels 57 is suppressed with respect to the brake fluid pressure of the front wheels. The brake fluid pressure of the rear wheel 57 is controlled such that the wheel speed of the rear wheel 57 approaches a target wheel speed determined based on the wheel speed of the front wheel 52.

The longitudinal braking force distribution control is started when the actual vehicle deceleration reaches the control start G. The control start G (so-called break point) is, as shown in FIG.
The deceleration corresponding to the intersection of the actual braking force distribution line and the ideal braking force distribution line is determined in both the constant load state and the light load state. This is to prevent the actual ratio of the rear wheel braking force from becoming larger than the ratio of the rear wheel braking force represented by the ideal braking force distribution line. When it is determined that the vehicle is in the constant load state, the control start GH is performed, and when it is determined that the vehicle is in the light load state, the control start GL is smaller than the control start GH.

In the present embodiment, the above-described brake assist control and the longitudinal braking force distribution control are performed in parallel. When it is determined that the vehicle is in the lightly loaded state, the brake assist control (control of the current supplied to the pressure control valve 70) is started with the start of the front / rear braking force distribution control. Further, the relationship between the driver's brake operation amount and the deceleration is set to be constant before and after the longitudinal braking force distribution control. In the brake assist control, the actual output pressure of the pressurizing device 150, the current supplied to the pressure control valve 70 so as to approach the target hydraulic pressure P _A ^* shown in FIG. 7 is controlled.

As shown in FIG. 7, the target hydraulic pressure P_A ^*Is the formula P_A ^*= Α (PM-PMS) + PMS. Where α is the braking force
Target hydraulic pressure P for change _A ^*Is the change gradient of PMS
Is when the longitudinal braking force distribution control is started, that is,
The master pressure at the time when the front and rear G reaches the control start GL.
In this case, the assist pressure ΔP_A ^*Is given by the formula ΔP_A ^*= P_A ^*-PM, pressure control to obtain this assist pressure
The supply current I to the valve 70 is determined.

When it is determined that the vehicle is in the constant load state, the brake assist control is executed when the master cylinder pressure is equal to the start pressure PMth.
It is started when it reaches. In the present embodiment, the target hydraulic pressure P _A ^* of the pressurizing device 150 is determined as shown in FIG. The target hydraulic pressure P _A ^* is obtained according to a different equation before and after the front and rear braking force distribution control is started, and after the start of the front and rear braking force distribution control, the assist pressure is larger than before the start. It is determined to be. Here, the target hydraulic pressure P _{A with} respect to the change gradient of the brake operating force
The change gradient of ^* is made larger after the start of the front-rear braking force distribution control than before the start (change gradient γ> change gradient β). In Before the front-rear braking force distribution control is started, the target hydraulic pressure P _A ^* is determined according to the equation ^{_{P A * = β (PM -PMth}} ) + PMth. Here, the start pressure PMth is a master pressure at the time when the assist control is started, and in the present embodiment, the loading state determination pressure PMths (hereinafter, simply referred to as determination pressure PMths) when the loading state is determined. Has the same value as Further, the assist pressure ΔP _A ^* in this case is obtained in accordance with the equation ΔP _A ^* = P _A ^* −PM, as in the case described above.
The supply current I to the pressure control valve 70 is determined. After the front and rear braking force distribution control is started, the target hydraulic pressure P _A ^*
It is determined according to the formula ^{_{P A * = γ (PM -PMS}} ') + PAS'. Here, PMS 'is the master pressure at the time when the longitudinal braking force distribution control is started, and PAS' is the pressurizing device 150 at the time when the longitudinal braking force distribution control is started.
, Which can be determined according to the equation PAS '= β (PM-PMth) + PMth. In this case, the master pressure PM is the hydraulic pressure PMS '. Further, the assist pressure is obtained according to the equation ΔP _A ^* = P _A ^* −PM, as in the case described above.

In the present embodiment, it is determined whether the loading state of the vehicle is a constant loading state or a light loading state.
It is known that in each of the constant loading state and the light loading state, the slip ratio of each wheel changes as shown in FIG. 10 according to the change of the master pressure. By utilizing this, it is determined whether the vehicle is in the constant load state or the light load state. When the condition shown in FIG. 6 is satisfied, it is determined that the vehicle is in the constant load state. Further, as shown in FIG. 10, in order to determine whether the vehicle is in the constant load state or the light load state based on whether the condition shown in FIG. In the present embodiment, the determination is made based on the slip state when the master pressure is the determination pressure PMths, as described above.

As shown in FIG. 10, when the master pressure PM is the judgment pressure PMths, that is, both the hydraulic pressure of the brake cylinder 56 of the front wheel 52 and the hydraulic pressure of the brake cylinder 60 of the rear wheel 57 are the judgment pressure PMths. Front wheel 5 in case
2. The slip ratios SF and SR of the rear wheels 57 in the constant load state are smaller than those in the light load state. Therefore, when the slip ratio SR of the rear wheel 57 is smaller than the positive determination threshold value α1, the slip ratio SF of the front wheel 52 is
Is smaller than the positive determination threshold α2, and the ratio (SR / SF) of the slip ratio SR of the rear wheels 57 to the slip ratio SF of the front wheels 52 is positive.
If it is smaller than 3, it can be considered as a constant load state. Also, the ratio reference value (VWRO / VWFO) of the front wheel to the reference wheel speed of the rear wheel (VWRO / VWFO) and the ratio (VWF / VW) of the rear wheel speed to the front wheel speed.
Even if the product of R) is smaller than the determination threshold α4, it can be determined that the vehicle is in the constant loading state. The load applied to each wheel is larger in the constant load state than in the light load state, but the center of gravity of the vehicle usually moves to the rear wheel side. As a result, the amount of increase in the load applied to the rear wheel becomes larger than the amount of increase in the load applied to the front wheel, and the ratio of the slip ratio of the rear wheel to the slip ratio of the front wheel (SR / SF) in a constant load state is light. It becomes smaller than the above ratio in the loaded state. The reference wheel speed is the wheel speed when no slip occurs.By considering the ratio reference value, the deformation state of the tire due to the slip is taken into consideration, and the change in the wheel speed due to the deformation of the tire is reduced. Can be. This makes it possible to accurately detect the ratio of the wheel speeds when a slip occurs.

In the flowchart showing the loading state determination program of FIG. 5, step S1 (hereinafter simply referred to as "S
1 ". In other steps, it is determined whether or not the brake pedal 10 is being operated. If the operation is not being performed, the loading state flag is reset in S2. In the present embodiment,
It is set in the case of the constant load state, and is kept in the reset state in the case of the light load state. If the brake operation is being performed, the master pressure is almost equal to the determination pressure P in S3.
It is determined whether it is Mths. When the pressure is substantially the determination pressure PMths, the determination is YE, and in S4, the calculations of the respective equations in FIG. 6 are performed, and in S5, it is determined whether the constant load condition is satisfied. If the constant loading condition is satisfied, it is determined in S6 that the constant loading state is set, and the flag is set. If the constant loading condition is not satisfied, it is determined in S7 that the vehicle is in the lightly loaded state, and the flag is kept in the reset state. It is not essential that the start pressure PMth and the determination pressure PMths be set to the same value, and the determination pressure PMths can detect the loaded state, and
It may be a value equal to or lower than the start pressure PMth.

Further, the brake assist control and the longitudinal braking force distribution control are performed in parallel. In the flowchart representing the longitudinal braking force distribution control program of FIG.
In, it is determined whether or not the vehicle is in the constant loading state. If the flag is in the set state, it is determined that it is in the constant load state and S22 and subsequent steps are executed. If the flag is in the reset state, it is determined that it is in the light load state and S30 and subsequent steps are executed. . When the flag is in the reset state, the loading state may not be determined in some cases. However, when the master pressure is smaller than the starting pressure PMth and the deceleration G is smaller than the light loading control start GL, the processing in S30 is performed. The determination is always NO, and the control of the pressurizing device 150 and the holding valve 10
0, the control of the pressure reducing valve 110 is not erroneously performed when the load is lightly loaded.

In the constant load state, it is determined in S22 whether the master pressure is equal to or higher than the start pressure PMth. If the pressure is equal to or lower than the start pressure PMth, the pressurizing device 15
Neither 0 nor the control valve devices 150, 152 are controlled. Neither the brake assist control nor the longitudinal braking force distribution control is performed. If the pressure is equal to or higher than the start pressure PMth, S
At 23, it is determined whether or not the front and rear G have reached the constant load control start GH. Before reaching the constant load control start GH, only the brake assist control is performed in S24 to S26. In the case of the constant loading state, the start pressure of the brake assist control is the pressure PMth. The inflow control valve 132 is switched to the open state, and the hydraulic fluid of the master cylinder 14 is pumped up by the pump 74 and is supplied to the brake cylinders 56 and 60 while being pressurized. It is controlled by the control of the pressure control valve 70. In this case, the holding valve 100 is kept open on both the front wheel side and the rear wheel side. The brake cylinder 56 of the front wheel 52,
The height of the brake cylinder 60 of the rear wheel 57 is controlled to be substantially the same as the output hydraulic pressure of the pressurizing device 150. Pressing device 150
Target pressure P _A ^* is a, as described above, is determined as shown by the solid line in FIG. 8, accordingly, the current supplied to the solenoid 84 of the pressure control valve 70 is determined.

When the front and rear G reach the constant load control start GH, the determination in S23 becomes YES, and S27-29.
, Both the assist control and the longitudinal braking force distribution control are performed. And than the assist pressure by the brake assist control is increased with the start of the front-rear braking force distribution control, the target fluid pressure of the pressure device 0.99 P _A ^* is determined as represented by the two-dot chain line in FIG. 8 . On the rear wheel side, the holding valve 10 is controlled so that the wheel speed of the rear wheel 57 becomes the target wheel speed determined based on the wheel speed of the front wheel 52.
0, the pressure reducing valve 110 is controlled to open and close. For example, based on a deviation between the target wheel speed and the actual wheel speed, a change state of the deviation, and the like, one of the pressure increasing mode, the pressure decreasing mode, and the holding mode is determined according to a table (not shown) stored in the ROM 184. , The duty control ratio is determined, and the holding valve 100 and the pressure reducing valve 11 on the rear wheel side are accordingly determined.
0 is controlled. The hydraulic pressure of the brake cylinder 60 of the rear wheel 57 is suppressed with respect to the hydraulic pressure of the brake cylinder 56 of the front wheel 52, and the wheel speed of the rear wheel 57 approaches the target wheel speed.

On the other hand, if it is determined that the vehicle is in the lightly loaded state, in S30, the front and rear G are set to the lightly loaded control start G
It is determined whether L has been reached. Light load control start GL
Prior to reaching, the assist control is not performed. When the light load control start GL has been reached, the determination in S30 is YES, and the assist control is started with the start of the front and rear braking force distribution control. In S31, as shown in FIG. 7, the target hydraulic pressure P _A ^* of the pressurizing device 150 is determined, and in S32, the pressure control valve 70 is accordingly set.
Is determined. Further, in S33, a command to switch the inflow control valve 132 to the open state is output, and
At 34, the opening and closing control of the holding valve 100 and the pressure reducing valve 110 on the rear wheel side is performed.

FIG. 9 shows how the vehicle deceleration changes with a change in the brake operating force when the control is performed as described above. As shown in FIG. 9, in the case of the constant loading state,
The assist control is started from a state where the brake operation force is not so large. Therefore, it is possible to reduce the difference in the relationship between the driver's brake operation amount and the deceleration between the case of the constant load state and the case of the light load state. Further, after the front and rear braking force distribution control is started, the output hydraulic pressure of the pressurizing device 150 is increased before the front and rear braking force distribution control is started. The change in the relationship between the brake operation amount and the deceleration before and after the longitudinal braking force distribution control can be reduced, and the driver's discomfort can be reduced. Further, as shown in the figure, the relationship between the driver's brake operation force and the deceleration before and after the front-rear braking force distribution control is performed, that is, the effect is constant (the deceleration linearly changes with the change in the brake operation force). (A changing relationship). Further, the relationship between the brake operation force and the deceleration can be prevented from changing significantly depending on the loaded state. Since the brake assist control and the front / rear braking force distribution control are performed based on the loaded state, the difference in the relationship between the brake operation force and the deceleration caused by the different loaded states can be reduced.

As described above, in the present embodiment, the parts for storing and executing the steps S22 to S28 and S32 to S32 of the front and rear braking force distribution program shown in the flowchart of FIG. Constitutes a pressurizing device control device, and a portion for storing and executing S23, 29, and 34 constitutes an individual hydraulic pressure control device.
The loading state detection device is configured by a portion that stores and executes a loading state detection program represented by the flowchart of FIG. 5 of the hydraulic pressure control device 180. When the loading state detection program is executed, the loading state detection method is performed. By executing the front and rear braking force distribution control program based on the detected loading state, the hydraulic pressure control method is performed. Become.

In the above-described embodiment, in the brake assist control, the pressurizing device 150 requests the driver in consideration of the reduction in the brake fluid pressure of the rear wheel 57 due to the longitudinal braking force distribution control. It is controlled based on the required braking force and the loaded state, and in the front-rear braking force distribution control, the rear wheel-side holding valve is set so that the wheel speed of the rear wheel 57 approaches a target wheel speed determined based on the wheel speed of the front wheel 52. 10
0, the opening / closing control of the pressure reducing valve 110 is performed, but the mode of the brake assist control and the longitudinal braking force distribution control is not limited to the above-described embodiment. For example,
Opening and closing of the pressurizing device 150, the holding valve 100 on the rear wheel side, and the pressure reducing valve 110 such that the hydraulic pressure of the brake cylinder 60 of the rear wheel 57 and the hydraulic pressure of the brake cylinder 56 of the front wheel 52 are close to the target hydraulic pressure, respectively. Control may be performed. From the front and rear G at that time and the ideal braking force distribution line in FIG. 11, the target value K of the ratio (PR / PF) of the hydraulic pressure PR of the brake cylinder 60 of the rear wheel 57 to the hydraulic pressure PF of the brake cylinder 56 of the front wheel 52. To determine. For example, in the lightly loaded state, the target value K of the ratio when the deceleration is Gn is a value (PRn / PFn). Further, the target hydraulic pressure of the pressurizing device 150 (same as the target hydraulic pressure of the brake cylinder 58 of the front wheels 52) is determined so that the target deceleration determined based on the driver's brake operation force is realized.
Then, based on the target hydraulic pressure of the pressurizing device 150 and the target value K of the ratio, the target hydraulic pressure of the brake cylinder 60 of the rear wheel 57 can be determined. For example, it is determined that the equation K = PR / PFPR + PF = P (Fs) is satisfied. Here, P (Fs) is a hydraulic pressure corresponding to a braking force necessary to achieve a target deceleration determined based on a driver's braking operation force.

Further, the current supplied to the pressure control valve 70 can be controlled so that the actual deceleration detected by the longitudinal G sensor 210 approaches the target deceleration. In the front-rear braking force distribution control, the rear wheel-side holding valve 100 and the pressure reducing valve 1
By controlling the opening and closing of the rear wheel 10, the wheel speed of the rear wheel 57 is controlled so as to approach the target wheel speed, and in the brake assist control, the current supplied to the pressure control valve 70 is adjusted so that the actual deceleration approaches the target deceleration. Is to be controlled. In this case, it is possible to perform control combining feedforward control based on the target hydraulic pressure and feedback control based on the deviation between the actual deceleration and the target deceleration.

Further, the longitudinal braking force distribution control can be performed from the start of the braking operation. Front wheel 5
2 so that the ratio between the hydraulic pressure of the brake cylinder 56 and the hydraulic pressure of the brake cylinder 60 of the rear wheel 57 approaches the ratio represented by the ideal braking force distribution line. Is controlled to be opened and closed. In this case, the brake assist control may be started from the start of the brake operation. Further, instead of starting the brake assist control with the start of the front and rear braking force distribution control, the brake assist control may be started slightly before the front and rear braking force distribution control is started. In this way, it is also possible to suppress a transient change in the relationship between the brake operation amount and the deceleration by the driver at the start of the longitudinal braking force distribution control. For example, the brake assist control is started when the actual front and rear G of the vehicle approaches the control start Gl by a set value or more. Furthermore, even in the case of a fixed loading state,
Before the front-rear braking force distribution control is started, the pressing device 15
The target hydraulic pressure of 0 may be determined to the magnitude represented by the two-dot chain line in FIG.

In the lightly loaded state, it is not essential that the brake assist control and the longitudinal braking force distribution control are started simultaneously. The assist control may be started when the assist control start condition is satisfied, that is, regardless of the longitudinal braking force distribution control. Further, in the above-described embodiment, the case where the front-rear braking force distribution control and the brake assist control are performed in parallel has been described. However, the left-right braking force distribution control, the vehicle stability control during braking, and the brake assist control are performed. It can be done in parallel. Also in these controls, the hydraulic pressure of each of the front, rear, left and right wheels is controlled separately, but the brake assist control is performed before and after the start of the control so that the change in effectiveness is suppressed. is there.

Further, in the above-described embodiment, the case has been described in which the front-rear braking force distribution control is performed before the boosting limit of the booster 12 in the lightly loaded state, but after the booster 12 reaches the boosting limit. The same applies to the case where the longitudinal braking force distribution control is started. In this case, as in the case of the constant load state, the pressing device 150
The target hydraulic pressure is increased after the front-rear braking force distribution control is started and before the start, and the brake operation force and the deceleration before and after the assist limit and before and after the front-rear braking force distribution control are increased. The height of the relationship is controlled so that the difference between the relationships is reduced, thereby reducing the driver's discomfort.

Further, regarding the method of detecting the loading state,
The present invention is not limited to the above embodiment. The conditions are not limited to the constant loading conditions shown in FIG. 6, and other conditions may be used. For example, it is not always necessary to consider the deformation of the tire. Further, the loading state can be detected in three or more stages or continuously. When the detection is continuously performed, the start pressure of the assist control, the change gradient when determining the target hydraulic pressure of the pressurizing device 150, the start pressure of the front-rear braking force distribution control, and the like are continuously determined based on the loading state. You can also decide.

Further, the brake circuit is not limited to that in the above embodiment. For example, X pipes may be used instead of the front and rear pipes. In this case, a left front wheel brake cylinder and a right rear wheel brake cylinder are connected to one pressurizing chamber of the master cylinder 14, and a right front wheel brake cylinder and a left rear wheel brake cylinder are connected to the other pressurizing chamber. And will be connected. The holding valve 10
0, Instead of an opening / closing valve that opens and closes the pressure reducing valve 110 by ON / OFF of the supply current, a hydraulic pressure control valve that generates a hydraulic pressure difference according to the supply current may be used.

Further, the structure of the pressure device 150 is not limited to that in the above embodiment. Instead of including the pressure booster, it may include a hydraulic control booster. An example of this is shown in FIG. In this brake device, the pressurizing device 300 includes a master cylinder 302, a booster 12, and a pump device 304, and the hydraulic pressure in a rear pressurizing chamber 308 behind the pressurizing piston 306 of the master cylinder 302 increases the pump pressure. The pump device 304 and the rear pressure chamber 3 are controlled by the control of the device 304.
08 and the like constitute an electromagnetically controlled hydraulic booster 310. The pump device 304 is a device that pressurizes the hydraulic fluid in the reservoir 312 and supplies the hydraulic fluid to the rear hydraulic chamber 308, and includes a pump 314, a pump motor 315, a pressure control valve 316, and the like. Output hydraulic pressure of the pump device 304, the rear pressure chamber 30
The hydraulic pressure of the working fluid supplied to 8 is controlled by controlling the supply current to the pressure control valve 316. Master cylinder 30
Both the output of the booster 12 and the driving force corresponding to the hydraulic pressure of the rear pressurizing chamber 308 are applied to the second pressurizing piston 306, and the hydraulic pressure corresponding to the sum of these outputs is applied to the front pressurizing chamber 318. Is generated. The hydraulic pressure in the front pressure chamber 318 is
00 hydraulic pressure.

In this embodiment, the pressure control valve 316
, The output hydraulic pressure of the pressurizing device 300 is controlled.
As the supply current to the pressure control valve 316 increases, the hydraulic pressure of the rear pressurizing chamber 308 is increased, and the output hydraulic pressure of the pressurizing device 300 when the brake operating force is the same can be increased. In the front-rear braking force distribution control, the hydraulic pressure of the brake cylinder 60 of the rear wheel 57 is suppressed with respect to the output hydraulic pressure of the pressurizing device 300 by controlling the holding valve 100 and the pressure reducing valve 110 on the rear wheel side. Brake cylinder 56
Is suppressed with respect to the hydraulic pressure. If the brake assist control and the front / rear braking force distribution control are performed in parallel, it is possible to reduce the driver's discomfort before and after the front / rear braking force distribution control.

In addition, [Problems to be solved by the invention,
Problem solving means and effects], and various modifications and improvements can be made based on the knowledge of those skilled in the art.

[Brief description of the drawings]

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

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

FIG. 3 is a diagram illustrating a periphery of a hydraulic control device of the brake device.

FIG. 4 is a flowchart showing a longitudinal braking force distribution control program stored in a ROM of the hydraulic control device.

FIG. 5 is a flowchart illustrating a loading state detection program stored in a ROM of the hydraulic control device.

FIG. 6 is a diagram showing the contents of execution in S4 of the flowchart representing the loading state detection program.

FIG. 7 is a diagram conceptually showing an example of a relationship between a target hydraulic pressure of a pressurizing device and a brake operating force in a lightly loaded state in the hydraulic pressure control device.

FIG. 8 is a diagram conceptually illustrating an example of a relationship between a target hydraulic pressure of a pressurizing device and a brake operating force in a constant loading state in the hydraulic pressure control device.

FIG. 9 is a diagram showing a change state of the deceleration of the vehicle in the brake device with a change in brake operation force.

FIG. 10 is a diagram showing a change state of the slip ratio in the brake device with a change in a brake operation force (master pressure).

FIG. 11 is a diagram showing an ideal braking force distribution control line.

FIG. 12 is a view showing a brake device according to another embodiment of the present invention.

[Explanation of symbols]

 14 Master cylinder 70 Pressure control valve 74 Pump 76 Pump motor 132 Inflow control valve 150 Pressurizing device 152,154 Individual hydraulic pressure control device 200 Master pressure sensor 204 Wheel speed sensor 210 Output hydraulic pressure sensor 212 Front and rear G sensor 300 Pressurizing device 302 Master cylinder 304 Pump device

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Claims (5)

[Claims] 1. A pressurizing device that pressurizes a hydraulic fluid and controls the hydraulic pressure, and at least one of the pressurizing device and a plurality of brake cylinders.
A plurality of control valve devices respectively provided between the two control valve devices and controlling a hydraulic pressure of a brake cylinder corresponding thereto, and controlling at least one of the plurality of control valve devices to correspond to the control valve device. An individual hydraulic pressure control device that suppresses the hydraulic pressure of the brake cylinder with respect to the hydraulic pressure of the pressurizing device; and a pressure increasing device that increases the hydraulic pressure of the pressurizing device with the start of control by the individual hydraulic pressure control device. A brake device comprising a pressure device control device. 2. The individual hydraulic pressure control device controls a control valve device corresponding to a rear wheel brake cylinder, thereby suppressing a hydraulic pressure of a rear wheel brake cylinder with respect to a hydraulic pressure of a front wheel brake cylinder. The brake according to claim 1, further comprising a front-rear braking force distribution control unit, wherein the pressurizing device control device includes a loading state corresponding control unit that controls a hydraulic pressure of the pressurizing device based on a loading state of the vehicle. apparatus. 3. A pressurizing device capable of controlling the hydraulic pressure while pressurizing the hydraulic fluid, a brake cylinder connected to the pressurizing device, and detecting a loaded state of a vehicle on which the brake device is mounted. A brake device comprising: a loading state detection device; and a pressing device control device that controls the pressing device based on the loading state detected by the loading state detection device. 4. The front wheel slip state and the rear wheel slip state when the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are substantially the same and at a predetermined height. And a loading state detection method for detecting the loading state of the vehicle based on the above. 5. A slip state of the front wheel and a slip state of the rear wheel when the hydraulic pressure of the front wheel brake cylinder and the hydraulic pressure of the rear wheel brake cylinder are substantially the same and at a predetermined height. A loading state detection step of detecting a loading state of the vehicle based on the control of the vehicle, and controlling a hydraulic pressure of at least one of the front and rear wheels of the brake cylinder based on the loading state of the vehicle detected in the loading state detection step. A hydraulic control method including a loading state corresponding hydraulic control step.