JP4337925B2 - Brake device - Google Patents

Description

  The present invention relates to a vehicle brake device, and more particularly to a vehicle brake device capable of reliably stopping or decelerating a vehicle during emergency braking.

In recent years, there has been a demand for a technique for shortening the braking distance of a vehicle as much as possible during emergency braking for urgently stopping or decelerating a vehicle such as an automobile.
In such a technique, in addition to a normal brake device that operates based on the pedaling force of the driver depressing the brake pedal, an emergency brake operation switch is provided, and when the driver operates the operation switch, the wheel A method for enhancing the braking force of the vehicle is conceivable. However, considering the driver's psychological state and reflexes during emergency braking, it is difficult to reliably operate the operation switch at the moment of emergency braking.

  Therefore, instead of providing an emergency brake operation switch, the brake pedal operation state by the driver is monitored, and the brake device itself determines whether or not the driver intends the emergency brake based on the operation state. A method of enhancing the braking force of the wheel when it is determined that the emergency braking is intended can be considered. In this method, in order to realize a reliable emergency stop or emergency deceleration, it is necessary to accurately monitor the operating state of the brake pedal and accurately determine whether or not the driver intends the emergency braking based on the operating state. Is required.

  The present invention has been made to satisfy the above-described requirements, and its purpose is to accurately determine whether or not the driver intends an emergency brake, and to perform braking only when the emergency brake is intended. An object of the present invention is to provide a brake device capable of assisting the braking force of the brake so that the distance becomes shorter.

The brake device according to claim 1, which is made to achieve the above object, includes an operation state detection unit, a braking force assist unit, a determination unit, an auxiliary operation permission unit, and an auxiliary operation execution unit . Operation status detection means, the driver monitors the operation state of the brake by the driver detects the operation state in order to determine whether the intended emergency braking. The braking force assisting unit assists the braking force of the wheel. Determination means determines that if the operation state of detection of said operating condition detecting means shows the time course of fixing to a constant value while monotonously increased is abnormal said operating state detecting means. The assisting operation permitting unit prohibits the assist of the braking force of the wheel by the braking force assisting unit when the determining unit determines that the operation state detecting unit is abnormal. When the operation state is equal to or greater than a predetermined value, the auxiliary operation executing means executes the assisting of the braking force when the change in time is indicated after the maximum value is reached.

Accordingly, in the present invention, when showing the change over time to stick to a fixed value while the operation state is monotonically increasing, the driver despite not operating the brake with the intention of emergency braking, by some failure It is determined that the operation state detection means is operating abnormally. Therefore, according to the present invention, by determining whether the operation state detection means is normal or abnormal, it is possible to accurately determine whether or not the driver has suddenly operated the brake intended for emergency braking.

  In the present invention, when the operation state detecting means is determined to be abnormal, the assist of the braking force of the wheel is prohibited. That is, the assist of the braking force of the wheel is permitted only when the operation state detecting means operates normally and the driver suddenly operates the brake with the intention of emergency braking. When the braking force of the wheel is assisted, the wheel is strongly braked by the amount of the assistance, so that the braking distance of the vehicle can be shortened. Thus, according to the present invention, when the driver does not operate the brake for an emergency brake and the operation state detection unit operates abnormally due to some failure, the braking force of the wheel is reduced. It is possible to prevent the assistance from being permitted and the braking force from being assisted unnecessarily.

The brake apparatus according to claim 2, in the brake apparatus of claim 1, wherein the determining means, normally at the time when the operation state is changed from the predetermined value after it has been determined that the abnormality of the operation state detecting means And after the predetermined time has elapsed since the operation state detection means is determined to be abnormal, it is determined again as normal.

Accordingly, in the present invention, it is operated abnormally operation state detecting means for some fault, thereafter, re-determined to be normal when the operation state is changed from a value which is fixed. This is because a failure of the operation state detection means due to some cause may be resolved naturally, and if the failure is resolved, it is not necessary to continue to determine that there is an abnormality. For this reason, by re-determining it as normal, it is possible to prepare for a failure of the operation state detection means that occurs thereafter or when the driver suddenly operates the brake with the intention of an emergency brake.

  Further, in the present invention, even if the operation state detecting means operates abnormally due to some failure, it is determined again as normal regardless of the presence or absence of an abnormal state after a lapse of a predetermined time. This is because once the operation state detection means operates abnormally, there is no risk of erroneous determination that the driver intends emergency braking after the abnormal operation, and the operation state detection means is determined to be normal. This is because no inconvenience arises.

A brake device according to a third aspect is the brake device according to the second aspect , wherein the braking force assisting means includes a wheel cylinder, a brake fluid supply means, a brake fluid removal means, and a control means. The wheel cylinder constitutes a hydraulic brake device for braking the wheel. The brake fluid supply means supplies brake fluid to the wheel cylinder. The brake fluid removing means removes the brake fluid from the wheel cylinder. The control means responds to the amount of change in the operation state after increasing the brake fluid pressure of the wheel cylinder to a predetermined level by supplying a predetermined amount of brake fluid from the brake fluid supply means to the wheel cylinder. Then, by adjusting the amount of brake fluid supplied from the brake fluid supply means and the amount of brake fluid removed from the brake fluid removal means, the brakes of the wheel cylinders are adjusted in accordance with the amount of change in the operation state. Adjust fluid pressure.

  Therefore, according to the present invention, when the change amount of the operation state increases, the brake fluid pressure of the wheel cylinder is increased, and when the change amount of the operation state decreases, the brake fluid pressure of the wheel cylinder is decreased, The brake fluid pressure applied to the wheel cylinder can be adjusted in response to fluctuations in the operating state. As a result, it becomes possible to always keep the assistance of the braking force of the wheel cylinders at a constant level corresponding to the fluctuation of the operation state, and the braking distance of the vehicle can be shortened because the wheels are strongly braked.

In the brake device described brake apparatus according to claim 4 to claim 2 or claim 3, auxiliary operation execution means, the auxiliary operation permission means permits the assistance of braking forces of the wheels, and, the operation in state is more than a predetermined value, and, the rate of change of the operation state obtained by differentiating the operation state time only when more than a predetermined value, the auxiliary braking force of the wheels to the braking force assist means Let it run.

Accordingly, in the present invention, the auxiliary operation permission means permits the assistance of braking forces of the wheels, and, in operation state is more than a predetermined value, and the change of the obtained operation state by differentiating the operating state time Only when all three conditions when the speed is equal to or higher than the predetermined value are satisfied, the assist of the braking force of the wheel is executed. When the driver operates rapidly and with the intention of emergency braking the brake, not only the operation state becomes a predetermined value or more, the rate of change of the operation state becomes a predetermined value or more. In other words, if these two conditions are not satisfied, the driver does not operate the brake suddenly, and whether or not the driver intends an emergency brake by determining whether or not these two conditions are satisfied. Can be accurately determined. Then, when the auxiliary operation permission means permits the assistance of the braking force of the wheel, the effect of the invention according to claim 1 can be further enhanced by executing the assistance of the braking force of the wheel.

In the brake device described brake apparatus according to claim 5 in any one of claims 1-4, wherein the operating state is Stepping force the driver depresses the brake pedal, or the driver holds the brake lever grip It is power .

Therefore, according to the present invention, by dealing with the operation state as pedal force or grip strength, it is possible to reliably monitor the operation state of the brake. In order to detect the pedaling force (grip force), the master cylinder pressure of the master cylinder to which the brake pedal (brake lever) is connected is indirectly detected using a pressure sensor, or the pedaling force (grip force) is detected using a pedaling force sensor. The detection may be performed directly or indirectly using a stroke sensor that detects the stroke of the brake pedal (brake lever). Since the detection is simple, the invention can be easily embodied.

According to a sixth aspect of the present invention, the brake device includes an operation state detection unit, a braking force assist unit, a determination unit, an auxiliary operation permission unit, and an auxiliary operation execution unit . Operation status detection means, the driver monitors the operation state of the brake by the driver detects the operation state in order to determine whether the intended emergency braking. The braking force assisting unit assists the braking force of the wheel. Determination means determines the time that the operation state of detection of said operating condition detecting means is fixed to a constant value without taking a maximal value is abnormal said operating condition detecting means when a predetermined or more. The assisting operation permitting unit prohibits the assist of the braking force of the wheel by the braking force assisting unit when the determining unit determines that the operation state detecting unit is abnormal. When the operation state is equal to or greater than a predetermined value, the auxiliary operation executing means executes the assisting of the braking force when the change in time is indicated after the maximum value is reached.

Therefore, in the present invention, the brake operation state by the driver, for example, the normality / abnormality of the master cylinder pressure detection sensor by the operation of the brake pedal is determined based on the comparison with the normal operation of the brake pedal operation by the driver. That is, the brake operation by the driver is usually returned by a pedal reaction force after being depressed, or unintentionally returned by the driver. Therefore, as the output of the operation status detection means, it will have a maximum value at the operating state if successful, if such output is actually performed, the operation state detection means can be determined that is normal.

  In addition, as an output of the operation state detection means, if it does not take a maximum value after increase (after increase due to the driver's brake operation), or is fixed to a constant value, or if both states continue, Since the output does not correspond to a normal driver's brake operation, it can be determined that the operation state detection means is abnormal.

An operating condition detecting means for detecting an operation state of the brake by the driver to determine whether the brake device driver described are intended to emergency braking to claim 7, the operation for detecting the operating condition detecting means If the rate of change of the operation state obtained the status and derivative time is a predetermined value or more KDp, and a determination means that there is a possibility of abnormality in the operating state detecting means.

The brake system of claim 8 in the brake system according to claim 7, in the operation state is more than a predetermined value KP, and, when the change rate of the operation state is equal to or larger than the prescribed value KDp, drivers Determine that emergency braking is intended.

  In the embodiments of the invention described below, the “operation state detection means” described in the claims or means for solving the problems is S100, S110 in the master cylinder 2, the pressure sensor 31, and the electronic control unit 71. Similarly, the “determination means” corresponds to the processing of S120 and S300 to S420 in the electronic control unit 71, and the “braking force assisting means” is also the master reservoir 3, the rear wheel piping system 4, and the front wheel piping system 5. And wheel cylinders 19-22, pipes A, B, E, F, electromagnetic switching control valves 32-35, 52-55, rear wheel pump 38 and front wheel pump 58, The “means” corresponds to the processing of S130 to S210 in the electronic control unit 71. Similarly, the “brake fluid supply means” corresponds to the master reservoir 3 and the pipelines B, A1, A2 F, E1, E2, pressure-increasing control valves 33-35, 53-55, rear wheel pump 38 and front wheel pump 58 correspond to the "brake fluid removal means" and the master cylinder 2 and pipes A, A1. , A2, E, E1, E2, the differential pressure control valves 32, 52, and the pressure increase control valves 34, 35, 54, 55. Similarly, the “control means” corresponds to the processing of S180 of the electronic control unit 71. Similarly, the “auxiliary operation executing means” corresponds to the processing of S120 to S170 and S190 to S210 of the electronic control device 71.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a schematic view of a brake pipe in the brake device of the present embodiment. In the four-wheeled vehicle, the present embodiment is applied to a vehicle having a front and rear two piping systems including a front wheel piping system for controlling the brakes of the front two wheels and a rear wheel piping system for controlling the brakes of the rear two wheels. A brake device is applied.

  The brake pedal 1 is connected to the master cylinder 2, and when a driver steps on the brake pedal 1, a master piston provided in the master cylinder 2 is pressed to generate a master cylinder pressure. The master reservoir 3 supplies brake fluid into the master cylinder 2 through a passage communicating with the master cylinder 2, or stores excess brake fluid in the master cylinder 2.

The master cylinder pressure generated by the master cylinder 2 is transmitted to the rear wheel piping system 4 and the front wheel piping system 5.
The rear wheel piping system 4 controls the braking of the right rear wheel 11 and the left rear wheel 12, and the front wheel piping system 5 controls the braking of the right front wheel 13 and the left front wheel 14. Each wheel 11-14 is provided with an electromagnetic pickup type or magnetoresistive element (MRE) type wheel speed sensor 15-18, and generates an output signal corresponding to the rotational speed of each wheel 11-14. Each wheel 11-14 is provided with each wheel cylinder 19-22 constituting a hydraulic brake device for braking each wheel.

  The rear wheel piping system 4 includes pipes A to D, pressure sensors 31, electromagnetic switching control valves 32 to 37, a rear wheel pump 38, an antilock brake device (ABS) reservoir 39, and check valves 40. To 43.

  The pipe A is connected to the master cylinder 2. In the vicinity of the master cylinder 2 in the pipeline A, a pressure sensor 31 that generates an output signal corresponding to the master cylinder pressure generated by the master cylinder 2 is disposed.

  The pipe A branches to the pipes A1 and A2 via the rear wheel differential pressure control valve 32. The rear wheel differential pressure control valve 32 is a two-position valve having a communication position and a differential pressure position. When the differential pressure control valve 32 for the rear wheel is in the differential pressure position, if a differential pressure of a predetermined value or more is applied to the upstream and downstream of the differential pressure control valve 32 for the rear wheel, a communication state is established, and the line A The pipeline A can be protected by preventing the pipelines A1 and A2 (the wheel cylinders 19 and 20) from having a pressure higher than the master cylinder 2 side.

  A pipe B is connected to the master reservoir 3. A pressure increase control valve 33 is disposed in the pipeline B. A pipeline C is connected to the ABS reservoir 39. A check valve 40 is disposed in the pipe C.

  A rear wheel pump 38 is connected to each of the pipelines A, A1, and A2. The rear wheel pump 38 draws the brake fluid stored in the master reservoir 3 from the pipe B through the pressure increase control valve 33 and discharges it to the pipes A, A1, and A2. The rear wheel pump 38 draws the brake fluid stored in the ABS reservoir 39 from the pipe C through the check valve 40 and discharges it to the pipes A, A1, and A2.

  Respective pressure increase control valves 34 and 35 are disposed in the respective pipelines A1 and A2. The wheel cylinders 19 and 20 are connected to the pipelines A1 and A2 via the pressure increase control valves 34 and 35, respectively.

  Wheel cylinders 19 and 20 and an ABS reservoir 39 are connected to both ends of the pipes D1 and D2, respectively. Respective pressure reducing control valves 36 and 37 are disposed in the pipe lines D1 and D2, respectively.

  A check valve 41 is connected in parallel to the differential pressure control valve 32 for the rear wheel, and only the flow of the brake fluid from the master cylinder 2 toward the pipe lines A1 and A2 is permitted. Excessive master cylinder pressure is eliminated. Further, check valves 42 and 43 are connected in parallel to the pressure increase control valves 34 and 35, respectively, and only the flow of brake fluid from the wheel cylinders 19 and 20 toward the pipe lines A1 and A2 is permitted. As a result, excessive brake fluid pressure applied to the wheel cylinders 19 and 20 is eliminated.

Each of the control valves 33 to 37 is a two-position valve having a communication position and a cutoff position.
By the way, the configuration of the front wheel piping system 5 is the same as that of the rear wheel piping system 4 except that the pressure sensor 31 is not provided. That is, the front wheel piping system 5 includes pipes E to H, electromagnetic switching control valves 52 to 57, a front wheel pump 58, an ABS reservoir 59, and check valves 60 to 63. The pipes E to H respectively correspond to the pipes A to D, the electromagnetic switching control valves 52 to 57 correspond to the electromagnetic switching control valves 32 to 37, respectively, and the front wheel pump 58 is provided on the rear side. Corresponding to the wheel pump 38, the ABS reservoir 59 corresponds to the ABS reservoir 39, and the check valves 60 to 63 correspond to the check valves 40 to 43, respectively.

FIG. 2 is a block diagram of an electronic control unit that controls the brake device shown in FIG.
Output signals from the wheel speed sensors 15 to 18 and the pressure sensor 31 are input to an electronic control unit (ECU) 71. The electronic control circuit 71 is a well-known microcomputer having a CPU, a ROM, a RAM, and an I / O circuit. When an ignition switch (not shown) is turned on, power is supplied. Based on the output signal, the electronic control circuit 71 is described later. Thus, drive control signals for the electromagnetic switching control valves 32 to 37 and 52 to 57 and the pumps 38 and 58 are generated.

In the brake device of this embodiment, ABS control is executed during normal braking, and brake assist (hereinafter referred to as BA) control described later is executed during emergency braking.
In the ABS control, the slip ratio of each wheel 11-14 is detected at the time of braking, and the brake fluid pressure applied to each wheel cylinder 19-22 is reduced, increased and maintained according to the detected slip ratio. By doing so, the vehicle is controlled to a slip rate (generally about 10% to 20%) that can be braked safely and quickly. In addition, the detection of the slip ratio of each wheel 11-14 is based on the wheel speed of each wheel 11-14 calculated based on the output signal of each wheel speed sensor 15-18, and the wheel speed of each wheel 11-14. The vehicle speed is calculated based on the vehicle speed calculated based on the vehicle speed.

  In the ABS control, in order to reduce the brake fluid pressure applied to the wheel cylinders 19 to 22, the differential pressure control valves 32 and 52 are set to the differential pressure positions, and the pressure increase control valves 33 to 35 and 53 to 55 are set. The shut-off position is set, and the pressure reducing control valves 36, 37, 56, 57 are set to the communication position. Then, the brake fluid of each wheel cylinder 19-22 flows into each ABS reservoir 39, 59 via each decompression control valve 36, 37, 56, 57, and the brake fluid pressure of each wheel cylinder 19-22 is decompressed. The

  Further, in the ABS control, in order to increase the brake fluid pressure applied to the wheel cylinders 19 to 22, the differential pressure control valves 32 and 52 and the pressure increase control valves 34, 35, 54, and 55 are set to the communication positions. The pressure increase control valves 33 and 53 and the pressure reduction control valves 36, 37, 56, and 57 are set to the cutoff positions. Then, the master cylinder pressure of the master cylinder 2 is directly applied to the wheel cylinders 19 to 22 via the pressure increase control valves 34, 35, 54, and 55, and the brake fluid pressure of the wheel cylinders 19 to 22 is increased. Is done.

  In the ABS control, in order to maintain the brake fluid pressure applied to the wheel cylinders 19 to 22, the differential pressure control valves 32 and 52 and the pressure increase control valves 33 and 53 are placed in communication positions, and the pressure increases. The control valves 34, 35, 54, 57 and the pressure reducing control valves 36, 37, 56, 57 are set to the cutoff position. Then, the brake hydraulic pressure of each wheel cylinder 19-22 is hold | maintained. In this state, when the driver depresses the depression force of depressing the brake pedal 1, the master cylinder pressure of the master cylinder 2 is reduced, and the brake fluid in the wheel cylinders 19 to 22 flows into the check valves 42, 43, 62, 63. Then, it flows into the master cylinder 2 via the differential pressure control valves 32 and 52, and the brake fluid pressure of the wheel cylinders 19 to 22 is reduced.

Next, details of processing performed by the electronic control unit 71 when BA control is executed during emergency braking will be described using the flowcharts shown in FIGS. 3 and 5 and the characteristic diagram shown in FIG.
As shown in FIG. 3, first, in step (hereinafter referred to as “S”) 100, the brake cylinder corresponding to the master cylinder pressure is calculated by calculating the master cylinder pressure of the master cylinder 2 corresponding to the output signal of the pressure sensor 31. Find the treading force of 1. That is, when the driver depresses the brake pedal 1, the master cylinder 2 generates a master cylinder pressure, and the pressure sensor 31 generates an output signal corresponding to the master cylinder pressure transmitted via the pipe A. Therefore, there is a corresponding relationship between the pedal force at which the driver depresses the brake pedal 1, the master cylinder pressure of the master cylinder 2, and the output signal of the pressure sensor 31. Therefore, if these correspondences are obtained in advance by experiments, the depression force of the brake pedal 1 can be calculated based on the output signal of the pressure sensor 31.

  Next, in S110, the pedal force change speed of the brake pedal 1 is calculated by differentiating in time the amount of change in the pedal force of the brake pedal 1 calculated in S100. This is not only to calculate the master cylinder pressure change speed (that is, the time gradient of the master cylinder pressure) by time differentiation of the change amount of the master cylinder pressure of the master cylinder 2, but also to the pedal force change speed and the master cylinder pressure. There is a corresponding relationship with the time gradient.

  Next, in S120, sensor sticking determination processing described later is performed. In this sensor sticking determination process, if it is determined that the output signal of the pressure sensor 31 is stuck to a constant value due to some failure, the sticking flag is set.

Next, in S130, it is determined whether or not the sticking flag is set. If the sticking flag is not set, the process proceeds to S140.
In S140, it is determined whether or not the BA control flag is set. When the process proceeds to this step for the first time, since the BA control flag is not set, the process proceeds to S150.

  In S150, it is determined whether or not the driver intends an emergency brake based on the depression force of the brake pedal 1 calculated in S100 and the depression force change speed of the brake pedal 1 calculated in S110. That is, as shown in FIG. 4, when the pedal effort of the brake pedal 1 is equal to or greater than the predetermined value KP and the pedal force change speed of the brake pedal 1 is equal to or greater than the predetermined value KDp, it is determined that the driver intends emergency braking. To do. That is, the emergency brake is determined only when the driver depresses the brake pedal 1 with a force stronger than the predetermined value KP and suddenly more than the predetermined value KDp. Note that the optimum values of the values KP and KDp are obtained in advance by experiments.

Next, in S160, when it determines with emergency brake in S150, it transfers to S170.
In S170, the BA control flag is set.

Next, in S180, BA control processing is executed.
That is, each differential pressure control valve 32, 52 is set to a differential pressure position, each pressure reduction control valve 36, 37, 56, 57 is set to a blocking position, and each pressure increase control valve 34, 35, 54, 55 is set to a communication position. Then, the pressure-increasing control valves 33 and 53 are set to the communication position for a predetermined time TD (for example, 20 ms) and then set to the cutoff position for a predetermined time TI (for example, 60 ms). Communication / blocking is switched alternately, and this switching is repeated a predetermined number of times N (for example, 5 times). The pumps 38 and 58 are driven simultaneously with the switching of the communication / blocking of the pressure increase control valves 33 and 53.

  Then, at the time of communication of each pressure increase control valve 33, 53, each pump 38, 58 causes the brake fluid stored in the master reservoir 3 to pass from each line B, F via each pressure increase control valve 33, 53. The water is pumped out and discharged from the pipes A and E to the wheel cylinders 19 to 22 through the pressure increase control valves 34, 35, 54 and 55. Therefore, the master cylinder pressure of the master cylinder 2 is not directly applied to the wheel cylinders 19 to 22, but the hydraulic pressure due to the brake fluid discharged from the pumps 38 and 58 is applied. As a result, the brake fluid pressure of the wheel cylinders 19 to 22 is increased by a predetermined number N of switching of communication / blocking of the pressure increase control valves 33 and 53, and the wheels 11 to 14 are braked.

  Here, the communication / blocking of each of the pressure increase control valves 33 and 53 is performed so that the brake fluid pressure applied to each of the wheel cylinders 19 to 22 is higher than the master cylinder pressure of the master cylinder 2 by a predetermined value. Each predetermined time TD, TI and a predetermined number N of switching are set.

  Thus, in the BA control process, the brake fluid pressure applied to each of the wheel cylinders 19 to 22 is controlled to be higher than the master cylinder pressure of the master cylinder 2 by a predetermined value. On the other hand, in the ABS control described above, the master cylinder pressure of the master cylinder 2 is applied to the wheel cylinders 19 to 22 as they are, and the brake fluid pressure of the wheel cylinders 19 to 22 is increased. Accordingly, during emergency braking in which BA control is executed, the braking force of each wheel cylinder 19 to 22 is assisted to brake the wheels 11 to 14 more strongly than during normal braking, so that the braking distance of the vehicle is further increased. Can be shortened.

  Next, in S190, it is determined whether or not to terminate the BA control by determining whether or not the depression force of the brake pedal 1 calculated in S100 is less than a predetermined value KP. When the process proceeds to this step for the first time, it is determined that the emergency brake is performed in S150, and therefore, it is determined that the depression force of the brake pedal 1 is not less than the predetermined value KP and the BA control is not terminated.

Next, in S200, when it is determined in S190 that the BA control is not terminated, the process returns to S100 and the next routine is executed.
If the sticking flag is set in S120, the process proceeds from S130 to S210, and the processes in S140 to S200 are not performed. In S210, the BA control flag is reset, and the process returns to S100 to execute the next routine. In other words, execution of BA control is prohibited when the sticking flag is set, and if the sticking flag is set before performing BA control, the BA control is not performed and the routine proceeds to the next routine and BA control is performed. If the fixing flag is set during the process, the BA control is immediately stopped and the next routine is started.

Also, if the emergency brake is not determined in S150, the process returns to S100 and the next routine is executed.
When the BA control flag is set in S170 of the previous routine, in the next routine, the process proceeds from S140 to S180, and the processes of S150 to S170 are not performed. That is, once the BA control flag is set, the BA control is continued in the next and subsequent routines until the BA control flag is reset in S210 or until the fixing flag is set in S120.

  Then, when the BA control process is performed in S180 of the previous routine, when the emergency stop or emergency deceleration of the vehicle is performed and the emergency brake is no longer necessary, the driver loosens the brake pedal 1 and therefore the next routine S100. The depressing force of the brake pedal 1 calculated in step S is reduced to less than a predetermined value KP. Then, in S190, it is determined that the BA control is finished, and the process proceeds from S200 to S210.

  By the way, in the BA control processing in S180 of the next routine, the pressure reducing control valves 36, 37, 56, and 57 are set to the cutoff position, and the pressure increasing control valves 34, 35, 54, and 55 are set to the communication position. Then, based on the pedaling force of the brake pedal 1 obtained in S100, when the pedaling force increases from the previous routine, the pressure-increasing control valves 33 and 53 are brought into the communication position and the pressure-difference control valves 32 and 52 are turned on. When the pedal pressure is reduced from the previous routine, the pressure-increasing control valves 33 and 53 are set to the communication position and the pressure control valves 32 and 52 are set to the communication position. At the same time, the pumps 38 and 58 are driven.

  Then, when the pressure-increasing control valves 33 and 53 are in communication (when the depressing force of the brake pedal 1 has increased from the previous routine), the pumps 38 and 58 are the same as in the case of first shifting to S180. Brake fluid stored in the reservoir 3 is pumped from the pipes B and F through the pressure-increasing control valves 33 and 53, and from the pipes A and E through the pressure-increasing control valves 34, 35, 54, and 55. To each wheel cylinder 19-22. Therefore, the brake fluid pressure of each wheel cylinder 19-22 becomes higher than the previous routine, and the braking force of each wheel 11-14 is strengthened.

  In addition, when the differential pressure control valves 32 and 52 are in communication (when the depressing force of the brake pedal 1 has decreased from the previous routine), the brake fluid in the wheel cylinders 19 to 22 flows from the pipelines A and E to the respective pressures. It flows into the master cylinder 2 via the pressure increase control valves 34, 35, 54, 55 and the differential pressure control valves 32, 52. Therefore, the brake hydraulic pressure of each wheel cylinder 19-22 becomes lower than the previous routine, and the braking force of each wheel 11-14 is weakened.

  Thus, when the pedal effort of the brake pedal 1 increases, the brake fluid pressure of each wheel cylinder 19-22 is made high, and when the pedal effort decreases, the brake fluid pressure of each wheel cylinder 19-22 is made low. The brake fluid pressure applied to each of the wheel cylinders 19 to 22 can be adjusted corresponding to the change in the pedal effort. As a result, the brake hydraulic pressure applied to each wheel cylinder 19 to 22 can always be higher than the master cylinder pressure of the master cylinder 2 by a predetermined value. That is, it is possible to always keep the assistance of the braking force of the wheel cylinders 19 to 22 by the BA control at a constant level in response to the fluctuation of the depression force of the brake pedal 1.

Next, the sensor sticking determination process in S120 of the main routine shown in FIG. 3 will be described with reference to FIG.
First, in S300, it is determined whether or not the sticking possibility flag is set. If the process proceeds to this step for the first time, since the possibility flag is not set, the process proceeds to S310.

In S310, it is determined whether or not the pedal force change speed calculated in S110 is equal to or greater than a predetermined value KDp. If the pedal force change speed is equal to or greater than the predetermined value KDp, the process proceeds to S320.
In S320, a sticking possibility flag is set.

  Next, in S330, it is determined whether or not the sticking flag is set. When the process proceeds to this step for the first time, since the sticking flag is not set, the process proceeds to S340.

In S340, it is determined whether or not the sticking possibility flag is set. If the sticking possibility flag is set, the process proceeds to S350.
In S350, it is determined whether or not a state in which the output signal of the pressure sensor 31 does not change continues for a predetermined time T2 (for example, 36 ms) or more, and if it continues, the process proceeds to S360.

In S360, the sticking flag is set, the process returns to the main routine, and the process proceeds to S130.
When the sticking possibility flag is set in S320 of the previous routine, the process proceeds from S300 to S370 in the next routine.

In S370, it is determined whether the set state of the sticking possibility flag has continued for a predetermined time T1 (for example, 100 ms) or more. If not, the process proceeds to S380.
In S380, it is determined whether or not the output signal of the pressure sensor 31 has decreased after taking the maximum value by determining whether or not the current output signal of the pressure sensor 31 is smaller than the maximum value of the past output signal. judge. If the output signal of the pressure sensor 31 has decreased after reaching the maximum value, the process proceeds to S390 because the output signal is decreasing, and if not, the process proceeds to S330 because the output signal is increasing. Transition.

In S390, the sticking possibility flag is reset, and the process proceeds to S330.
If the sticking flag is set in S360 of the previous routine, the process proceeds from S330 to S400 in the next routine.

In S400, it is determined whether or not there is a change in the output signal of the pressure sensor 31 since the fixing flag is set, and if there is no change, the process proceeds to S410.
In S410, it is determined whether or not the set state of the sticking flag continues for a predetermined time T3 (for example, 300 ms) or more. If it continues, the process proceeds to S420.

In S420, the sticking flag is reset, the process returns to the main routine, and the process proceeds to S130.
In S310, if the pedal force change speed calculated in S110 is less than the predetermined value KDp, the process proceeds to S330.

  Further, when the sticking possibility flag is not set in S340, when the state in which the output signal of the pressure sensor 31 does not change continues for the predetermined time T2 or more in S350, the sticking flag is set in the predetermined time in S410. In each case where the period does not continue for T3 or more, the process returns to the main routine and proceeds to S130.

In S370, if the set state of the sticking possibility flag continues for the predetermined time T1 or more, the process proceeds to S390.
In S400, if there is a change in the output signal of the pressure sensor 31 from when the fixing flag is set to the present, the process proceeds to S420.

  Next, the operation of the brake device of the present embodiment will be described using the time charts shown in FIGS. 6 to 8, the pedaling force at which the driver actually depresses the brake pedal 1, the level of the output signal of the pressure sensor 31, the pedaling force change speed calculated by the electronic control unit 71 in S110, the sticking possibility flag, The change over time of the set / reset state of the sticking flag and the brake fluid pressure of each wheel cylinder 19 to 22 is shown.

6 and 7 show a case where the output signal of the pressure sensor 31 has risen due to some failure even though the driver has not actually depressed the brake pedal 1.
The cause of the failure in which the output signal of the pressure sensor 31 rises regardless of the depression of the brake pedal 1 is not only the failure of the pressure sensor 31 itself, but also the failure of the master cylinder 2, the master cylinder 2 and the pressure sensor 31. There is a failure in the connecting pipe line. When the output signal of the pressure sensor 31 rises due to such a failure, the output signal of the pressure sensor 31 shows a temporal change that is fixed to a constant value while being monotonously raised, and does not show a sudden rise or fall.

  As shown in FIG. 6, when the output signal of the pressure sensor 31 rises, the depression force of the brake pedal 1 corresponding to the output signal of the pressure sensor 31 is calculated (S100), and the depression force change speed is calculated (S110). Then, the sticking possibility flag is set (S320) at time t1 (S310: YES) when the pedal force change speed increases as the output signal of the pressure sensor 31 increases and becomes equal to or greater than the predetermined value KDp.

  When the sticking possibility flag is set, the sticking flag is set at time t2 (S350: YES) when a state in which the output signal of the pressure sensor 31 does not change continues for a predetermined time T2 (for example, 36 ms) or longer. (S360).

  Then, the sticking possibility flag is reset at time t3 (S370: YES) when the sticking possibility flag setting state continues for a predetermined time T1 (eg, 100 ms) or more (S390). Thereafter, the sticking flag is reset (S420) at time t4 (S410: YES) when the sticking flag is set for a predetermined time T3 (for example, 300 ms) or longer.

  Thus, even if the output signal of the pressure sensor 31 increases due to some failure and the pedaling force change speed increases and becomes equal to or higher than the predetermined value KDp, the state in which the output signal of the pressure sensor 31 does not change is the predetermined time. If it continues for more than T2 (time t2), the sticking flag is set. As shown in the flowchart of FIG. 3, when the sticking flag is set (S130: YES), the brake fluid pressure of each wheel cylinder 19 to 22 is not increased by the BA control. Further, since the driver does not depress the brake pedal 1, the master cylinder pressure of the master cylinder 2 does not change. Therefore, the brake fluid pressure of each wheel cylinder 19-22 does not change.

  As described above, when the output signal of the pressure sensor 31 shows a change over time that is fixed to a constant value while increasing monotonously, the fixing flag is set, and execution of the BA control is prohibited. Therefore, the increase in the output signal of the pressure sensor 31 due to some failure is not erroneously determined to be caused by the driver depressing the brake pedal 1 suddenly with the intention of emergency braking. It is possible to prevent the BA control from being executed.

If the sticking flag is set during the execution of the BA control, the BA control is immediately stopped.
Further, even if the output signal of the pressure sensor 31 rises due to some failure and the fixing flag is set once, the state in which the output signal of the pressure sensor 31 does not change continues to rise for a certain time or more, and the fixing flag is set. If it continues for a predetermined time T3 or more (time t4), the sticking flag is reset.

  That is, if the output signal of the pressure sensor 31 is fixed once and does not change as it is, the pedaling force change speed is maintained at zero. Therefore, even if the output signal of the pressure sensor 31 is stuck due to any failure, there is no risk of misjudging that the driver intends the emergency brake after the sticking, and the BA control is executed by such wrong judgment. It will never be done. Therefore, there is no inconvenience even if the sticking flag is reset to return to the initial state.

  By the way, even if the output signal of the pressure sensor 31 rises due to some failure, if the time gradient of the rise of the output signal is gentle, the pedaling force change speed does not rise to the predetermined value KDp. Is not set and the sticking flag is not set.

  However, as long as the pedal force change speed does not increase to the predetermined value KDp, there is no possibility that the driver erroneously determines that the emergency braking is intended, no matter what the failure causes the output signal of the pressure sensor 31 to be fixed. The BA control is not executed by such erroneous determination. Therefore, no inconvenience occurs even if the fixing flag is not set.

  In the example shown in FIG. 7, the setting of the sticking possibility flag (time t1) and the setting of the sticking flag (time t2) are performed by the same operation as in the example shown in FIG. Then, as shown in FIG. 7, when the sticking flag is set, the sticking flag is reset at time t5 (S400: YES) when the output signal of the pressure sensor 31 is changed (S420).

  That is, even if the output signal of the pressure sensor 31 rises due to some failure and the fixing flag is set once, if the output signal of the pressure sensor 31 changes thereafter (time t5), the fixing flag is reset.

  The failure that the output signal of the pressure sensor 31 rises due to various causes described above may be resolved naturally. If the failure is resolved, it is not necessary to set the sticking flag and prohibit execution of BA control. For this reason, if the output signal of the pressure sensor 31 changes after the fixing flag is set, the fixing flag is reset as the failure has been resolved, so that the failure occurring after that or when the driver intends emergency braking. Can be provided for the BA control to be executed.

  FIG. 8 shows a case where the output signal of the pressure sensor 31 rises because the driver actually depresses the brake pedal 1 suddenly. In addition, in the time chart of the brake fluid pressure of each wheel cylinder 19-22, the time-dependent change of the master cylinder pressure of the master cylinder 2 is shown with the dotted line.

  When the driver suddenly depresses the brake pedal 1 with the intention of emergency braking, the output signal of the pressure sensor 31 shows a temporal change that decreases rapidly after reaching a maximum value. That is, overshoot is seen in the temporal change of the pedal force of the brake pedal 1 and the output signal of the pressure sensor 31.

  In the example shown in FIG. 8, the setting of the sticking possibility flag (time t1) is performed by the same operation as in the example shown in FIG. Then, as shown in FIG. 8, the sticking possibility flag is reset at time t6 (S380: YES) when the output signal of the pressure sensor 31 decreases after taking the maximum value (S390).

  As described above, when the output signal of the pressure sensor 31 rises because the driver actually depresses the brake pedal 1, the output signal of the pressure sensor 31 decreases after reaching the maximum value (time t6), and can be fixed. The presence flag is reset and the sticking flag is prevented from being set. Therefore, if the execution of the BA control is permitted, the depression force of the brake pedal 1 is equal to or greater than the predetermined value KP, and the depression force change speed of the brake pedal 1 is equal to or greater than the predetermined value KDp, the BA control is performed and each wheel cylinder 19-22. The brake fluid pressure is increased.

  By the way, when the driver depresses the brake pedal 1, the master cylinder pressure of the master cylinder 2 is increased, and if the BA control is not executed, the master cylinder pressure is directly applied to the wheel cylinders 19-22. Therefore, the brakes of the wheel cylinders 19 to 22 are performed from the time t0 when the driver starts depressing the brake pedal 1 to the time t7 when the brake fluid pressure of the wheel cylinders 19 to 22 is increased by the BA control. The hydraulic pressure is equal to the master cylinder pressure. That is, between the time point t0 and the time point t7, the wheels 11 to 14 are braked with the same braking force as during normal braking, and from the time point t7, the wheels 11 to 14 are braked with a strong braking force by BA control. Here, since the time point t7 is defined by the predetermined time T2, if the predetermined time T2 is set sufficiently short, a reliable emergency stop or emergency deceleration can be realized even if the BA control is started from the time point t7. it can.

  As described above in detail, in the brake device of this embodiment, the operation state of the brake pedal is accurately monitored by detecting the master cylinder pressure of the master cylinder 2 using the pressure sensor 31. Then, the electronic control device 71 calculates the pedaling force of the brake pedal 2 corresponding to the master cylinder pressure and the pedaling force changing speed corresponding to the time gradient of the master cylinder pressure, and based on the pedaling force and the pedaling force changing speed, the driver It is determined whether or not an emergency brake is intended, and the BA control is executed to assist the braking force of each wheel cylinder 19 to 22 and enhance the braking force of each wheel 11 to 14 compared to normal braking. .

  Furthermore, before the execution of the BA control, the change in the output signal of the pressure sensor 31 is monitored, and if the output signal shows a change over time that is fixed to a constant value while increasing monotonously, the increase in the signal due to some failure Therefore, it is determined that the driver does not intend emergency braking, and execution of BA control is prohibited. Further, when the output signal of the pressure sensor 31 rises rapidly and shows a change over time that takes a maximum value and then decreases, it is determined that the driver intends an emergency brake and the execution of the BA control is permitted. ing.

  Therefore, according to the brake device of the present embodiment, whether or not the driver intends the emergency brake is accurately determined, and only when the emergency brake is intended, the BA control is executed to shorten the braking distance. The brake can be controlled as follows.

In addition, this invention is not limited to the said embodiment, You may change as follows, Even in that case, the effect | action and effect similar to the said embodiment can be acquired.
(1) In the above embodiment, the master cylinder pressure of the master cylinder 2 is detected by the pressure sensor 31, and the depression force of the brake pedal 1 is obtained based on the master cylinder pressure, but instead of the pressure sensor 31, the brake pedal 1 A pedal force sensor that directly detects the pedal force may be used.

  Further, instead of the pressure sensor 31, a stroke sensor that detects the amount of change in the stroke of the brake pedal 1 when the driver depresses the brake pedal 1 may be used. In this case, since there is a correspondence between the stroke change amount of the brake pedal 1 and the pedal effort of the brake pedal 1, the pedal effort can be calculated from the stroke change amount if the correspondence relationship is obtained in advance by experiments. .

  (2) If the processing of S400 shown in FIG. 5 is omitted and the output signal of the pressure sensor 31 is fixed once, even if the output signal of the pressure sensor 31 changes after that, the set of the fixing flag is held and reset is performed. It may not be performed. In this case, the sticking flag cannot be reset unless the fault causing the output signal of the pressure sensor 31 to rise is solved and repaired.

  (3) If the process of S410 shown in FIG. 5 is omitted and the output signal of the pressure sensor 31 is fixed once and does not change as it is, the set of the fixed flag may be held and the reset may not be performed. In this case, the fixing flag cannot be reset unless the failure that caused the output signal of the pressure sensor 31 to rise is repaired.

  (4) The above embodiment is applied to a four-wheeled vehicle, but may be applied to a two-wheeled vehicle, a three-wheeled vehicle, or a vehicle having five or more wheels. When applied to a two-wheeled vehicle or a three-wheeled vehicle, the gripping force change speed is calculated by detecting the gripping force by which the driver grips the brake lever instead of the pedaling force of the brake pedal and differentiating the change amount of the gripping force with time. Then, the pedaling force in the above embodiment is replaced with the gripping force, and the pedaling force changing speed is replaced with the gripping force changing speed, so that the same processing as in the above embodiment is performed.

  (5) Although the above embodiment is applied to a brake piping system having two front and rear piping systems, an X piping system having a front wheel and a rear wheel at a diagonal position as a pair of piping systems, and a left wheel and a right wheel respectively. The present invention may be applied to various brake piping systems such as a left and right two piping system as a set of piping systems.

The hydraulic circuit diagram of the brake device of one embodiment. The block diagram of the electronic controller which controls the brake device of one Embodiment. The flowchart for demonstrating operation | movement of the brake device of one Embodiment. The characteristic view for demonstrating operation | movement of the brake device of one Embodiment. The flowchart for demonstrating operation | movement of the brake device of one Embodiment. The time chart for demonstrating operation | movement of the brake device of one Embodiment. The time chart for demonstrating operation | movement of the brake device of one Embodiment. The time chart for demonstrating operation | movement of the brake device of one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brake pedal 2 ... Master cylinder 3 ... Master reservoir 4 ... Rear-wheel piping system 5 ... Front-wheel piping system 11-14 ... Wheel 19-22 ... Wheel cylinder A-H ... Pipe line 31 ... Pressure sensor 32-37, 52- 57 ... Electromagnetic switching control valve 38 ... Rear wheel pump 58 ... Front wheel pump 58 71 ... Electronic control unit

Claims (8)

An operating condition detecting means for detecting the operation state in order to determine whether the driver monitors the operation state of the brake is intended for emergency braking by the driver,
Braking force assisting means for assisting the braking force of the wheel;
A determination unit and when the operation state to be detected exhibits a change with time of fixing to a constant value while monotonously increased is abnormal said operating state detecting means of the operating condition detecting means,
If the determination means determines that the operation state detection means is abnormal, an auxiliary operation permission means for prohibiting the assist of the braking force of the wheel by the braking force auxiliary means ;
A brake device comprising: an assisting action executing means for assisting the braking force when the operating state is greater than or equal to a predetermined value and shows a temporal change that decreases after taking a maximum value . The brake device according to claim 1, wherein
The determination unit re-determines that the operation state is normal after the operation state detection unit has been determined to be abnormal, and after a predetermined time has elapsed since the operation state detection unit has been determined to be abnormal. Is a brake device characterized by re-determining that it is normal . The brake device according to claim 2,
The braking force assisting means is
A wheel cylinder constituting a hydraulic brake device for braking the wheel;
Brake fluid supply means for supplying brake fluid to the wheel cylinder;
Brake fluid removal means for removing brake fluid from the wheel cylinder;
By increasing the brake fluid pressure of the wheel cylinder to a predetermined level by supplying a predetermined amount of brake fluid from the brake fluid supply means to the wheel cylinder, By adjusting the amount of brake fluid supplied from the brake fluid supply means and the amount of brake fluid removed from the brake fluid removal means, the brake fluid pressure of the wheel cylinder is adjusted in accordance with the amount of change in the operation state. Control means to
Brake device characterized by comprising a. In the brake device according to claim 2 or 3,
The auxiliary operation executing means is the operation state obtained by allowing the auxiliary operation permission means to assist the braking force of the wheel, the operation state being a predetermined value or more, and time differentiation of the operation state. A braking device characterized in that the braking force assisting means assists the braking force of the wheel only when the change speed of the vehicle is greater than or equal to a predetermined value . In the brake device according to any one of claims 1 to 4,
The brake device according to claim 1, wherein the operating state is a pedaling force by which a driver depresses a brake pedal or a gripping force by which the driver grips a brake lever . Operation state detection means for monitoring the operation state of the brake by the driver and detecting the operation state in order to determine whether or not the driver intends emergency braking;
Braking force assisting means for assisting the braking force of the wheel;
A determination unit that determines that the operation state detection unit is abnormal when a time during which the operation state detected by the operation state detection unit is fixed to a constant value without taking a maximum value is equal to or longer than a predetermined value;
If the determination means determines that the operation state detection means is abnormal, an auxiliary operation permission means for prohibiting the assist of the braking force of the wheel by the braking force auxiliary means;
An auxiliary operation executing means for executing the assist of the braking force when the operation state is equal to or greater than a predetermined value and shows a temporal change that decreases after taking the maximum value;
Brake device characterized by comprising a. An operation state detecting means for detecting an operation state of a brake by the driver in order to determine whether or not the driver intends an emergency brake;
A determination unit that determines that the operation state detection unit is likely to be abnormal when a change speed of the operation state obtained by time differentiation of the operation state detected by the operation state detection unit is equal to or greater than a predetermined value KDp. When
Brake device characterized by comprising a. The brake device according to claim 7,
A brake device , wherein the driver determines that an emergency brake is intended when the operation state is a predetermined value KP or more and the change speed of the operation state is the predetermined value KDp or more .

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