JP2010184642A - Vehicle braking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle braking device that detects a partial hydroplaning phenomenon, properly responding to the road surface conditions. <P>SOLUTION: The vehicle braking device 1 includes: lock state suppressing means 7b for reducing hydraulic pressure in wheel cylinders corresponding to each wheel, when the slip rate is larger than the target slip rate; and determining means 7c, that detects the hydraulic pressure in each wheel cylinder corresponding to each wheel, and, if the hydraulic pressure in a wheel cylinder corresponding to either a right or left rear wheel is in the high hydraulic pressure range not less than a first predetermined value β, and the hydraulic pressure in the wheel cylinder corresponding to a front wheel, which positions in the front side and coincides with the positional relationship in the right and left direction with respect to the rear wheel corresponding to the wheel cylinder in the high pressure range, is in a low hydraulic pressure range lower than a second predetermined value γ, and the lock state suppressing means 7b has reduced the hydraulic pressure, then determines that the hydroplaning phenomenon is occurring at the front wheel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle braking device suitable for being applied to vehicles such as passenger cars, trucks, buses and the like.

  Usually, in a vehicle, based on a command by a driver's depression of a brake pedal or a braking command of a device for controlling the speed of the vehicle such as ACC (Adaptive Cruse Control), a wheel cylinder of a brake device provided for each wheel The hydraulic pressure is supplied from the master cylinder, the hydraulic pressure is further supplied from the wheel cylinder to the brake cylinder of each wheel, and the brake pad is pressed against the brake disc that is drivingly connected to the hub and rotates with the wheel by the brake cylinder. The vehicle is braked and the vehicle is decelerated or stopped.

  In recent years, in such a brake device, there is a so-called ABS (Anti-Lock Brake System) that prevents or suppresses the locked state of the wheels, thereby suppressing the stop distance or the braking distance from extending. May apply.

  In such an ABS, when the vehicle speed is obtained from the wheel speeds of the front, rear, left and right wheels, and the slip ratio obtained by dividing the value obtained by subtracting the vehicle speed from each wheel speed by the vehicle speed is greater than the target slip ratio, the locked state is Decreasing the hydraulic pressure in the wheel cylinder corresponding to the wheel in which the locked state is generated by determining that it has occurred, and reducing the pressing force of the brake pad against the brake disc to suppress the locked state .

  However, when a water film is interposed between the tire and the road surface and the friction coefficient between the tire and the road surface becomes extremely small, a so-called hydroplaning phenomenon occurs, and the driver steers and brakes the vehicle. However, it is impossible to drive freely. As a technique for detecting such a hydroplaning phenomenon, for example, there is a technique shown in Patent Document 1.

  Even if ABS operates and the oil pressure in the wheel cylinder is reduced, if the hydroplaning phenomenon occurs, the frictional force does not act on the tire from the road surface, so the wheel speed does not increase and the locked state is eliminated. In the technique described in Patent Document 1, when the decompressed state is maintained for a predetermined time, the state of not being continued continues, the hydraulic pressure in the wheel cylinder is further reduced, and the reduced pressure state is continued. Has proposed a control for removing the water film by temporarily increasing the hydraulic pressure in the wheel cylinder.

JP-A 63-269767

  However, in such a prior art, the road surface on which the right wheel of the vehicle travels is a wet road where water exists on the road surface, and the road surface on which the left wheel of the vehicle travels does not have water on the road surface. Hydroplaning only on the right front wheel on dry roads or low-μ roads with snow or ice on the road surface, that is, when the vehicle is straddling across different road surfaces in the left-right direction Even if the phenomenon occurs, the partial hydroplaning phenomenon cannot be detected, and the decrease in vehicle deceleration is not significant, so the driver can run without notice and be aware of the occurrence of the hydroplaning phenomenon. Therefore, there arises a problem that steering and braking may occur. This is the same even if the left-right positional relationship is reversed.

  In addition, the road surface on which the front wheels of the vehicle travel is a wet road, and the road surface on which the rear wheels of the vehicle travel is a dry road or a low μ road, that is, the vehicle straddles a road surface in a different state in the front-rear direction. When the vehicle is in a straddling state, even if the hydroplaning phenomenon occurs only on the front wheels, the partial hydroplaning phenomenon cannot be detected, and the decrease in vehicle deceleration is not significant. There arises a problem that the driver may run without knowing and may perform steering and braking without being aware of the occurrence of the hydroplaning phenomenon.

  In view of the above problems, an object of the present invention is to provide a vehicle braking device that can detect a partial hydroplaning phenomenon by appropriately responding to a road surface condition.

In order to solve the above problem, the vehicle braking device according to the present invention is:
Lock state suppression means for reducing the hydraulic pressure in the wheel cylinder corresponding to each wheel when the slip ratio is larger than the target slip ratio;
The hydraulic pressure in each wheel cylinder corresponding to each wheel is detected, and the hydraulic pressure in the wheel cylinder corresponding to either the left or right rear wheel is a high hydraulic pressure region that is equal to or higher than a first predetermined value,
A low hydraulic pressure range in which the hydraulic pressure in the wheel cylinder corresponding to the front wheel located on the front side matches the rear wheel corresponding to the wheel cylinder corresponding to the wheel cylinder in the high hydraulic pressure range and is less than a second predetermined value. And when the locked state suppression means is reducing the oil pressure, it comprises determination means for determining that a hydroplaning phenomenon has occurred in the front wheel,
It is characterized by that.

  In addition, the said lock state suppression means is ECU which can implement | achieve ABS control, for example. Further, the hydraulic pressure may be detected by a hydraulic sensor provided in each wheel cylinder, or may be obtained by estimation from the hydraulic pressure of the master cylinder.

  According to the vehicle braking device of the present invention, the hydraulic pressure in the wheel cylinder corresponding to the right rear wheel is in the high hydraulic pressure range, and the hydraulic pressure in the wheel cylinder corresponding to the right front wheel is in the low hydraulic pressure range. Thus, when the lock state suppression means is reducing the hydraulic pressure, the road surface on which the right wheel of the vehicle travels is a wet road in which water exists on the road surface, and the left wheel of the vehicle travels. Based on the fact that the road surface is a low μ road or a dry road and the hydroplaning phenomenon occurs only on the right front wheel, the determination means causes the hydroplaning phenomenon only on the right front wheel. Can be determined.

  Similarly, under the condition that the hydraulic pressure in the wheel cylinder corresponding to the left rear wheel is in the high hydraulic pressure range, and the hydraulic pressure in the wheel cylinder corresponding to the left front wheel is in the low hydraulic pressure range, the lock state suppressing means When the hydraulic pressure is reduced, the road surface on which the left wheel of the vehicle travels is a wet road where water is present on the road surface, and the road surface on which the right wheel of the vehicle travels is snow or ice on the road surface. And the determination means has a hydroplaning phenomenon only on the left front wheel based on the fact that the hydroplaning phenomenon occurs only on the left front wheel. Can be determined.

  In any of the above-described cases, based on the determination by the determination means, for example, a slip indicator or a buzzer provided in the vehicle is operated by the notification means, so that the driver of the vehicle is left or right It can be notified that the hydroplaning phenomenon has occurred only on the front wheels. As a result, the driver is in a situation where the behavior of the vehicle becomes unstable due to the occurrence of a hydroplaning phenomenon on either the left or right front wheels of the vehicle, and the driver cannot exhibit sufficient performance in terms of braking, steering, and driving. With this awareness, driving can be continued based on higher attention.

Or in order to solve said problem, the vehicle braking device which concerns on this invention is the following.
Lock state suppression means for reducing the hydraulic pressure in the wheel cylinder corresponding to each wheel when the slip ratio is larger than the target slip ratio;
Detect the oil pressure in each wheel cylinder corresponding to each wheel,
The hydraulic pressure in the wheel cylinder corresponding to both the left and right rear wheels is in a high hydraulic pressure range above the first predetermined value, and the hydraulic pressure in the wheel cylinder corresponding to both the left and right front wheels is in a low hydraulic pressure range less than the second predetermined value. And determining means for determining that a hydroplaning phenomenon has occurred in both the left and right front wheels when the lock state suppressing means is reducing the hydraulic pressure,
This may be a feature.

  According to the vehicle braking apparatus of the present invention, the hydraulic pressure in the wheel cylinder corresponding to both the left and right rear wheels is a high hydraulic pressure region that is equal to or higher than the first predetermined value, and the hydraulic pressure in the wheel cylinder corresponding to both the left and right front wheels is In a low hydraulic pressure range less than a second predetermined value, when the lock state suppression means reduces the hydraulic pressure, the road surface on which the front wheels of the vehicle travel is a wet road, and the rear of the vehicle By utilizing the fact that the road surface on which the side wheel travels is a dry road or a low μ road, and that the hydroplaning phenomenon occurs only on the front wheels, the determination means can apply the hydroplaning phenomenon only to the left and right front wheels. Can be determined to have occurred.

  Even in this case, based on the determination by the determination means, for example, a slip indicator or a buzzer provided in the vehicle is operated by the notification means, so that the driver of the vehicle is hydrostatically only to both the left and right front wheels. It can be notified that the planing phenomenon has occurred. As a result, the driver is in a situation where hydroplaning phenomenon occurs on both the left and right front wheels of the vehicle, and the behavior of the vehicle becomes unstable, and the driver cannot exhibit sufficient performance in braking, steering, and driving. The driver can continue driving based on higher attention.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle braking device which can be made to respond | correspond appropriately with a road surface condition, and can detect a partial hydroplaning phenomenon can be provided.

1 is a block diagram showing an embodiment of a vehicle braking device according to the present invention. It is a flowchart which shows the control content of one Embodiment of the vehicle braking device which concerns on this invention. It is a schematic diagram which shows the specific condition where one Embodiment of the vehicle braking device which concerns on this invention is applied. It is a schematic diagram which shows the specific condition where one Embodiment of the vehicle braking device which concerns on this invention is applied.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of a vehicle braking device according to the present invention including hydraulic piping.

  As shown in FIG. 1, a vehicle braking device 1 includes a brake pedal 2, a stroke sensor 3 provided on the brake pedal 2 for detecting a stroke value of the brake pedal 2, and a pedaling force input to the brake pedal 2 by a driver. A vacuum booster 4 connected to a negative pressure generating pipe that generates negative pressure using the negative pressure of the engine, a master cylinder 5 that generates operating hydraulic pressure from the basic hydraulic pressure by the boosted pedal force, It comprises a reservoir 6 for storing hydraulic pressure, a brake ECU 7 (Brake Electronic Control Unit), a wheel speed sensor 8, a buzzer 9, and a brake actuator 10.

  The wheel speed sensor 8 is provided at four locations corresponding to the front, rear, left and right (FR, FL, RR, RL) wheels, detects each wheel speed, and outputs the detection result to the brake ECU 7.

  The buzzer 9 is provided, for example, on a meter panel of a vehicle, and when a partial hydroplaning phenomenon occurs, it is sounded based on the control of the brake ECU 7 to notify the driver of the occurrence of the partial hydroplaning phenomenon. To call attention.

  The operation hydraulic pressure or the basic hydraulic pressure is supplied to the inlet of the hydraulic piping of the brake actuator 10. The brake actuator 10 includes an FR system and an FL system. For example, the FR system hydraulically brakes the right front wheel FR and the left rear wheel RL, and the FL system hydraulically brakes the left front wheel FL and the right rear wheel RR. Since the configuration of both is the same, only the FR system is used. This will be described with reference to FIG.

  The brake actuator 10 includes a hydraulic pipe, a holding valve 11, a holding valve 12, a pressure reducing valve 13, a pressure reducing valve 14, a reservoir 15, and a master cylinder pressure sensor 16.

  The hydraulic piping is first branched at the branch point A from the inlet toward the downstream side, and the master cylinder pressure sensor 16 is disposed upstream of the branch point A, so that the operating hydraulic pressure or basic hydraulic pressure in the master cylinder 5 (driver is pedaled) When no pedal force is applied to 2, the operation hydraulic pressure = basic hydraulic pressure is detected and the detection result is output to the brake ECU 7.

  A branch point B is provided on the downstream side of the hydraulic pipe after branching from the branch point A to the left side. A holding valve 11 for the right front wheel FR is provided on one downstream side of the branch point B, and the left rear side is provided on the other side. A holding valve 12 for the wheel RL is provided. On the other hand, the hydraulic piping branched rightward from the branch point A is communicated with the reservoir 15.

  A branch point C is provided on the downstream side of the holding valve 11, the wheel cylinder 17 of the right front wheel FR is connected to one hydraulic pipe downstream of the branch point C, and the pressure downstream of the branch point C of the other pipe is reduced. The valve 13 communicates with the reservoir 15.

  Similarly, a branch point D is provided on the downstream side of the holding valve 12, the wheel cylinder 18 of the left rear wheel RL is connected to one hydraulic pipe downstream of the branch point D, and the branch point D of the other pipe is connected. The downstream is communicated with the reservoir 15 via the pressure reducing valve 14. The holding valve 11 and the holding valve 12 supply operating hydraulic pressure to the wheel cylinders 17 and 18 as supply hydraulic pressure.

  The brake ECU 7 includes, for example, a CPU, a ROM, a RAM, a data bus connecting them, and an input / output interface. The CPU performs predetermined processing according to a program stored in the ROM. The suppression means 7b, the determination means 7c, and the alerting | reporting means 7d are comprised.

  The control means 7a of the brake ECU 7 holds the brake actuator 10 based on the stroke sensor value detected by the stroke sensor 3 shown in FIG. 1 and the master pressure sensor value detected by the master cylinder pressure sensor 16 = the hydraulic pressure in the master cylinder. Hydraulic braking is performed by appropriately controlling the valves 11 and 12 and the pressure reducing valves 13 and 14.

  The lock state suppression means 7b of the brake ECU 7 obtains four wheel speeds from the front, rear, left and right wheel speed sensors 8, calculates the average value of the wheel speeds of the rolling wheels, calculates the vehicle speed, and calculates the vehicle speed from each wheel speed. When the slip ratio is obtained by dividing the reduced value by the vehicle speed and braking is performed by the control means 7a, and the slip ratio of a certain wheel becomes larger than the target slip ratio, the pressure reducing valve 13 corresponding to the corresponding wheel or 14 is appropriately opened to reduce the wheel cylinder pressure inside the wheel cylinder 17 or 18 and perform ABS control to suppress the locked state.

  The determination means 7c of the brake ECU 7 estimates and calculates the hydraulic pressures PFL, PRL, PFR, PRR of the wheel cylinders 17 or 18 corresponding to the wheels FL, RL, FR, RR, respectively, from the master pressure sensor values.

  The determination means 7c calculates the vehicle body deceleration (negative value) from the differential value of the vehicle speed calculated by the lock state suppression means 7b, the hydraulic braking is executed by the control means 7a, and the vehicle body deceleration has a certain value. is greater than α and the braking force is not sufficiently obtained, the hydraulic pressure PFL and the hydraulic pressure PRL are in a hydraulic range corresponding to a low μ road, and the hydraulic pressure PRR is higher than a first predetermined value β corresponding to a wet road. When the hydraulic pressure range is a low hydraulic pressure range where the hydraulic pressure PFR is less than the second predetermined value γ and all the wheels are under ABS control, a hydroplaning phenomenon of one wheel has occurred in the right front wheel FR. Is determined.

  Note that the hydraulic pressure PFR of the right front wheel FR is in a low hydraulic pressure range less than the second predetermined value γ is that ABS control is executed by the lock state suppressing means 7b, and a water film exists between the right front wheel FR and the road surface. When the hydroplaning phenomenon occurs, the friction force acting between the road surface and the right front wheel FR is zero even if the hydraulic pressure of the corresponding wheel cylinder is reduced. Since the wheel speed returns and does not increase, the ABS control, that is, the pressure reduction process is continuously executed, and the hydraulic pressure PFR decreases.

  Further, the high hydraulic pressure region equal to or higher than the first predetermined value β is a hydraulic pressure region corresponding to a case where the road surface is a wet road, and a region slightly lower than a hydraulic pressure region corresponding to a case where the road surface is a dry road. The hydraulic pressure region corresponding to the road surface is a low μ road is a region lower than the hydraulic pressure region corresponding to the road surface being a wet road, and the friction coefficient between the road surface and the tire is different. Thus, the hydraulic pressure that reaches the locked state is determined based on the decreasing order of the dry road, the wet road, and the low μ road.

  Here, the certain value α is obtained by converting the braking force from each hydraulic pressure by a predetermined calculation formula, estimating the friction coefficient μ between the road surface and the tire, and generating the estimated friction coefficient μ in the vehicle. It is assumed that a deceleration that can be calculated is calculated.

  Further, the determination means 7c is a case where the hydraulic braking is executed by the control means 7a and the vehicle body deceleration is larger than a certain value α and the braking force is not sufficiently obtained, and the hydraulic pressure PFR and the hydraulic pressure PRR are low μ. A hydraulic pressure region corresponding to the road, the hydraulic pressure PRL is a high hydraulic pressure region equal to or higher than the first predetermined value β corresponding to the wet road, and the hydraulic pressure PFL is a low hydraulic pressure region less than the second predetermined value γ, and When the right front wheel FR, the right rear wheel RR, the left front wheel FL, and the left rear wheel RL are all under the ABS control, it is determined that the one-wheel hydroplaning phenomenon has occurred in the left front wheel FL.

  Here again, the fact that the hydraulic pressure PFL of the left front wheel FL is a low hydraulic pressure region less than the second predetermined value γ is that the ABS control is executed by the lock state suppressing means 7b, and a water film is formed between the left front wheel FL and the road surface. And the hydroplaning phenomenon occurs, the friction force does not act between the road surface and the left front wheel FL even if the hydraulic pressure of the corresponding wheel cylinder is reduced, and the wheel of the left front wheel FL Since the speed does not increase again, the pressure reduction process is continuously executed and the hydraulic pressure PFL is reduced.

  In addition, the determination means 7c is a high hydraulic pressure region where the hydraulic pressures PRR and PRL are equal to or higher than the first predetermined value β corresponding to the wet road, and the hydraulic pressures PFR and PFL are low hydraulic pressure regions less than the second predetermined value γ. In addition, when all the wheels are under the ABS control, if it continues for a certain time δ or more, it is determined that the hydroplaning phenomenon of the right front wheel FR and the left front wheel FL has occurred.

  Here again, the fact that the hydraulic pressure PFL of the left front wheel FL and the hydraulic pressure PFR of the right front wheel FR are in a low hydraulic pressure range less than the second predetermined value γ indicates that the ABS control is executed by the lock state suppression means 7b and the left front wheel FL and the road surface In the case where a water film exists between the right front wheel FR and the road surface and a hydroplaning phenomenon has occurred, the road surface and the left front wheel FL During this time, no frictional force is generated between the road surface and the right front wheel FR, and the wheel speeds of the left front wheel FL and the right front wheel FR do not increase again, so that the pressure reduction process is continuously performed and the hydraulic pressure PFL decreases. appear.

  The notification means 7d of the brake ECU 7 sounds the buzzer 9 to notify the driver when the determination means 7c determines that a hydroplaning phenomenon of one wheel or a hydroplaning phenomenon of both the left and right front wheels has occurred. To call attention.

  Hereinafter, the control content of the vehicle braking device 1 of a present Example is demonstrated using a flowchart and a schematic diagram. FIG. 2 is a flowchart showing the control contents of the vehicle braking apparatus 1 according to the present invention. FIG. 3 is a schematic diagram showing a specific situation where the vehicle braking device 1 according to the present invention is applied. FIG. 4 is a schematic diagram showing a specific situation where the vehicle braking device 1 according to the present invention is applied.

  In step S1 shown in FIG. 2, the lock state suppression means 7b of the brake ECU 7 detects and acquires the wheel speed from the four wheel speed sensors 8, and in step S2, the determination means 7c of the brake ECU 7 determines the master pressure sensor value. In step S3, the lock state suppression means 7b calculates the vehicle speed, the slip ratio, and the vehicle body deceleration. In step S4, the determination means 7c determines the oil pressure of the wheel cylinders 17 and 18 of each wheel as the master pressure sensor value. Estimate and calculate from

  In step S5, the determination means 7c performs the hydraulic braking, the vehicle body deceleration is greater than a certain value α, the hydraulic pressure PFR of the right front wheel FR is in the low hydraulic pressure range, and the hydraulic pressure PRR of the right rear wheel RR is high. It is determined whether the pressure is within the hydraulic pressure range and the ABS is operating. If the result is affirmative, the process proceeds to step S6. If the result is negative, the process proceeds to step S7.

  In step S6, the notification means 7d of the brake ECU 7 sounds the buzzer 9 to notify the driver that the one-wheel hydroplaning phenomenon has occurred in the right front wheel FR, thereby calling attention.

  In step S7, the determination means 7c performs hydraulic braking, the vehicle body deceleration is greater than a certain value α, the hydraulic pressure PFL of the left front wheel FL is in the low hydraulic pressure range, and the hydraulic pressure PRL of the left rear wheel RL is high. It is determined whether the pressure is within the hydraulic pressure range and the ABS is operating. If the result is affirmative, the process proceeds to step S8. If the result is negative, the process proceeds to step S9.

  In step S8, the notifying means 7d of the brake ECU 7 sounds the buzzer 9 to notify the driver that the one-wheel hydroplaning phenomenon has occurred in the left front wheel FL, thereby calling attention.

  In step S9, the determination means 7c determines that the hydraulic pressure PFR of the right front wheel FR and the hydraulic pressure PFL of the left front wheel FL are in the low hydraulic pressure range, and the hydraulic pressure PRR of the right rear wheel RR and the hydraulic pressure PRL of the left rear wheel RL are in the high hydraulic pressure range. Then, it is determined whether or not the state in which the ABS control is being performed continues for a certain time δ or more. If the result is affirmative, the process proceeds to step S10, and if the result is negative, the process proceeds to RETURN. In addition, by making it a requirement for determination to continue for a certain period of time δ or more, events such as μ jumps that occur at the time of transfer between high and low are excluded from determination targets.

  In step S10, the notification means 7d of the brake ECU 7 sounds the buzzer 9 to notify the driver that the front wheel hydroplaning phenomenon has occurred on the front wheels FR and FL, thereby calling attention.

  According to the vehicle braking device 1 of the present embodiment realized by the control contents described above, the following operational effects can be obtained. That is, both the right front wheel FR and the right rear wheel RR are locked under the condition that the hydraulic pressure in the wheel cylinder corresponding to the right rear wheel RR is in the high hydraulic pressure range and the hydraulic pressure in the wheel cylinder corresponding to the right front wheel FR is in the low hydraulic pressure range. When the ABS control for reducing the hydraulic pressure is executed by the state suppression means 7b, as shown in FIG. 3, the road surface on which the wheels FR and RR on the right side of the vehicle travel are wet roads where water is present on the road surface. Based on the knowledge that the road surface on which the wheels FL, RL on the left side of the vehicle travel is a low μ road and the hydroplaning phenomenon occurs only in the right front wheel FR, the brake ECU 7 The determination means 7c determines that the hydroplaning phenomenon has occurred only in the right front wheel FR by comparing the hydraulic pressure PRR of the right rear wheel RR and the hydraulic pressure PFR of the right front wheel FR. Can.

  Similarly, both the left rear wheel RL and the left front wheel FL are provided under the condition that the hydraulic pressure in the wheel cylinder corresponding to the left rear wheel RL is in a high hydraulic pressure range and the hydraulic pressure in the wheel cylinder corresponding to the left front wheel FL is in a low hydraulic pressure range. When the ABS control for reducing the hydraulic pressure is executed by the lock state suppression means 7b, the road surface on which the left wheels FL and RL of the vehicle run is reversed on the road surface, contrary to that shown in FIG. The road surface on which the wheels FR and RR on the right side of the vehicle travel is a low μ road where snow or ice exists on the road surface, and the hydroplaning phenomenon occurs only on the left front wheel FL. Based on the knowledge that it can be regarded as a case, the judgment hand 7c of the brake ECU 7 determines that the hydraulic plani is applied only to the left front wheel FL by comparing the hydraulic pressure PFL of the left front wheel FL and the hydraulic pressure PRL of the left rear wheel RL. It can be determined that grayed phenomenon has occurred.

  Furthermore, according to the vehicle braking device 1 of the present embodiment, the hydraulic pressure in the wheel cylinder corresponding to both the left and right rear wheels RR and RL is a high hydraulic pressure region that is equal to or higher than the first predetermined value β, and both the left and right front wheels FR, When the hydraulic pressure in the wheel cylinder corresponding to FL is in a low hydraulic pressure range less than the second predetermined value γ and ABS control is being performed on both the front wheels and the rear wheels, as shown in FIG. It can be considered that the hydroplaning phenomenon occurs only on the front wheels FR and FL when the road surface on which the vehicle is traveling is a wet road and the road surface on which the rear wheel is traveling is a dry road and then the rear wheel is transferred to a wet road. Based on the knowledge, by comparing the hydraulic pressures PFL, PFR on the front wheel side with the hydraulic pressures PRR, PRL on the rear wheel side, the judgment means 7c of the brake ECU 7 applies hydroprediction to both the left and right front wheels FR, FL only. It can be determined that the phenomenon of erosion has occurred.

  As a result, it is possible to accurately detect the occurrence of a hydroplaning phenomenon only on one side of the front wheel or only on the front wheel, which is difficult to detect in the prior art, by a simple logic of comparing the hydraulic pressures of the wheels. . As a result, the occurrence of the hydroplaning phenomenon can be detected based on the determination of the determination means 7c, and the buzzer 9 is sounded by the notification means 7d so that only the left or right front wheel or the front wheels are Only that the hydroplaning phenomenon has occurred can be notified. As a result, the driver is in a situation where the behavior of the vehicle becomes unstable, and he / she is cautious on the basis of higher attention, noticing that braking, steering and driving cannot perform as desired. Driving can be continued.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

  For example, a hydraulic sensor that directly detects the hydraulic pressure in the wheel cylinders 17 and 18 corresponding to each wheel is provided, and the determination unit 7c of the brake ECU 7 executes the determination process based on the detection value of the hydraulic sensor. it can.

  Further, the buzzer 9 can be replaced with a slip indicator provided on a meter panel or the like. Furthermore, based on the control of the notification means 7d of the brake ECU 7, in addition to the notification by the buzzer 9, it is also possible to execute a control for removing the water film by temporarily increasing the hydraulic pressure in the wheel cylinder.

  The present invention relates to a technology for braking a vehicle, and detects a partial hydroplaning phenomenon by appropriately responding to a road surface condition by adding a relatively minor logic change without adding a new component. Therefore, the present invention is useful when applied to various vehicles such as passenger cars, trucks, and buses.

DESCRIPTION OF SYMBOLS 1 Vehicle braking device 2 Brake pedal 3 Stroke sensor 4 Vacuum booster 5 Master cylinder 6 Reservoir 7 Brake ECU
7a Control means 7b Lock state suppression means (ABS)
7c Determination means 7d Notification means 8 Wheel speed sensor (FR, FL, RR, RL)
9 Buzzer 10 Brake actuator 11 Holding valve 12 Holding valve 13 Pressure reducing valve 14 Pressure reducing valve 15 Reservoir 16 Master cylinder pressure sensor 17 Wheel cylinder 18 Wheel cylinder

Claims (2)

  Lock state suppression means for reducing the hydraulic pressure in the wheel cylinder corresponding to each wheel when the slip ratio is larger than the target slip ratio, and detecting the hydraulic pressure in each wheel cylinder corresponding to each wheel, The hydraulic pressure in the wheel cylinder corresponding to the rear wheel is a high hydraulic pressure region that is equal to or higher than a first predetermined value, and the positional relationship in the left-right direction matches the rear wheel corresponding to the wheel cylinder that is the high hydraulic pressure region, and When the hydraulic pressure in the wheel cylinder corresponding to the front wheel located on the front side is in a low hydraulic pressure range lower than a second predetermined value and the lock state suppressing means reduces the hydraulic pressure, hydroplaning phenomenon occurs on the front wheel. A vehicle braking apparatus comprising: a determination unit that determines that the occurrence has occurred.   When the slip ratio is larger than the target slip ratio, the lock state suppression means for reducing the hydraulic pressure in the wheel cylinder corresponding to each wheel and the hydraulic pressure in each wheel cylinder corresponding to each wheel are detected, and The hydraulic pressure in the wheel cylinder corresponding to the wheel is a high hydraulic pressure range greater than or equal to a first predetermined value, and the hydraulic pressure in the wheel cylinder corresponding to both the left and right front wheels is a low hydraulic pressure range less than a second predetermined value, and the lock A vehicle braking apparatus comprising: a determination unit that determines that a hydroplaning phenomenon has occurred in both the left and right front wheels when the state suppression unit reduces the hydraulic pressure.

Images