JP3501201B2 - Automatic braking system for vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic brake device for a vehicle, in which the braking force is smoothly released when the automatic brake is stopped to stabilize the behavior of the vehicle.

[0002]

2. Related Background Art This type of vehicle automatic brake device is incorporated in a brake system utilizing pneumatic pressure, and is mainly used for actively controlling the behavior and traveling speed of the vehicle. For example, JP-A-5-24531 discloses an air-over-hydraulic brake type brake control device suitable for traction control of a vehicle as one of automatic brakes.

In this brake control device, the braking pressure of each wheel can be controlled by a modulator, and a normal main brake pressure line and an automatic brake line are connected to this modulator via a shuttle valve mechanism. Has been done. In addition, a control valve is inserted in the automatic brake line, and this control valve is opened during traction control, whereby high air pressure in the air tank is directly supplied to the modulator via the shuttle valve mechanism. . In order to generate braking pressure to each wheel from such high air pressure, the modulator has a built-in hold valve and decay valve, and the opening / closing control of these valves allows the braking pressure supplied to that wheel to be adjusted. It has become. When the traction control is completed, the control valve is closed and the air pressure supply from the air tank to the modulator is shut off.On the other hand, the hold valve of the modulator is returned to the normally open state and the supply from the main brake pressure line is stopped. It becomes possible.

[0004]

In the above-described brake control device, the main brake pressure line and the automatic brake pressure line are connected to the modulator via the shuttle valve mechanism, so that the brake is released by the normal brake pedal operation. This is advantageous in that the air pressure in the air chamber can be discharged from both the main and automatic brake pressure lines.
However, when the automatic braking is released, the modulator and the control valve are simultaneously returned to their rest position, so that the high residual pressure in the automatic braking pressure line is discharged only from the exhaust port of the control valve. Therefore, when the automatic brake control ends, the residual pressure in the automatic brake pressure line directly acts on the air chamber. As a result, the braking force of the wheels may change undesirably, and the behavior of the vehicle may become unstable at the end of the traction control.

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to smoothly switch to the main brake without changing the braking force of the brake at the end of the automatic brake control. An object of the present invention is to provide an automatic braking device for a vehicle that can perform the operation.

[0006]

In order to achieve the above object, an automatic brake device for a vehicle according to a first aspect of the invention receives air pressure from an air pressure source and brakes the air pressure according to a driver's operation. The main brake pressure supply means for outputting to the drive unit via the first pneumatic pressure path and the supply of the air pressure from the air pressure source, and the air pressure of this air pressure source is directed to the brake drive unit to the second air pressure source. An air supply valve having a supply position for outputting via the pressure path and a cut-off position for cutting off the output of air pressure to the second air pressure path and exhausting air in the second air pressure path; Two air pressure paths are connected to each other, and a double check valve for outputting the air pressure on the high pressure side of the outputs from the main brake pressure supply means and the air supply valve through the output port, the output port of the double check valve, and the brake drive unit. A third pneumatic path connecting between the The first position for opening the third air pressure passage and the upstream portion of the third air pressure passage on the double check valve side are shut off, and the downstream portion of the third air pressure passage on the brake drive unit side is opened to the atmosphere. A pressure control valve having at least a second position for controlling the air pressure of the brake drive unit by switching the air supply valve to the air supply position and controlling the operation of the pressure control valve under a predetermined traveling condition of the vehicle. Is equipped with a control means for adjusting the
When stopping the automatic brake, the control means switches the pressure regulating valve to the first position and operates after a lapse of a predetermined time after returning the air supply valve to the shutoff position.

According to the vehicle automatic brake device of the first aspect, when the automatic brake is stopped, the air supply valve is first returned to the shut-off position, and then the pressure regulating valve is switched to the first position. Therefore, when the third air pressure passage is opened, the air pressure raised in the second air pressure passage is completely discharged through the air supply valve, so that the residual pressure in the second air pressure passage is reduced. It does not flow into the third pneumatic path.

In the automatic braking device for a vehicle according to a second aspect of the invention, the control means sets the stop time of the automatic braking at the time of the driver's braking operation, and the predetermined time is output from the main brake pressure output means. It is set within the time it takes for the air pressure to reach the pressure control valve. In this case, if the driver operates the brake, the automatic braking is immediately stopped. Also, since the above-mentioned automatic brake end operation is completed within the time until the main brake pressure is raised,
Switching from the automatic brake to the main brake is done smoothly.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a vehicle automatic brake device of the present invention will be described below with reference to the drawings. First, Fig. 1
Referring to FIG. 1, there is schematically shown a configuration of a braking system in a vehicle 1 to which the automatic braking device of the embodiment is applied. The vehicle 1 is, for example, a large vehicle such as a truck or a bus, and therefore, the left and right rear wheels WRL and WRR that are drive wheels are both parallel two-wheel types. On the other hand, the left and right front wheels WFL and WFR, which are steering wheels, are of the normal type.

The brake system of the vehicle 1 is composed of an air-over hydraulic brake which operates the hydraulic brake by utilizing air pressure. That is, the wheel cylinders 2 provided on each of the wheels WFL, WFR, WRL, WRR receive hydraulic pressure to operate a wheel brake (not shown).
Further, a hydraulic pipeline 3 is connected to each wheel cylinder 2, and an air over hydraulic booster 4 for converting air pressure into hydraulic pressure is connected to these hydraulic pipelines 3.
Are connected respectively. In other words, in this brake system, the hydraulic line from the hydraulic cylinder of the air over hydraulic booster 4 to the wheel cylinder 2 is
It is configured as a brake drive unit that drives each wheel brake.

Next, the pneumatic path for outputting pneumatic pressure to each of the above-mentioned individual brake drive units will be described in detail. A pneumatic line 8 extends from each air over hydraulic booster 4, and each pneumatic line 8 is connected to an output port of a double check valve 12, respectively. Further, the pressure adjusting valve 10 is provided in each pneumatic line 8.
Are inserted respectively.

A supply pipe 13 is connected to one inlet port of each double check valve 12, and these supply pipes 13 are provided with two relay valves 14.
Two are connected to each. That is, the two supply pipelines 13 on the front wheels WFL and WFR sides are respectively connected to one relay valve 14, and the two supply pipelines 13 on the rear wheels WRL and WRR sides are respectively connected to the other relay valve 14. It is connected. Furthermore, from each relay valve 14, the air supply line 2
4 respectively extend, and these air supply lines 24 are connected to the corresponding air tanks 6, respectively. That is, the pneumatic line from one inlet port of the double check valve 12 to the air tank 6 via the relay valve 14 is shared by the front wheel side and the rear wheel side. In addition,
Air is supplied from a compressor to these air tanks 6, and the compressor is driven by an engine.

Further, signal pressure lines 16 are connected to the input ports of each relay valve 14, and these signal pressure lines 16 are connected to the corresponding air tank 6 via a dual type brake valve 18. There is. Therefore,
The signal pressure line from the brake valve 18 to the relay valve 14 via the signal pressure line 16 is also shared by the front wheel side and the rear wheel side.

On the other hand, an air supply pipe 20 is connected to the other inlet port of each double check valve 12, and each of the two air supply pipes 20 is connected to two air supply valves 22. . That is, the two air supply lines 2 on the front wheel side
0 is connected to one air supply valve 22, and the two air supply pipe lines 20 on the rear wheel side are connected to the other air supply valve 22.
That is, the downstream portion of each air supply conduit 24 is branched and connected to the relay valve 14 and the air supply valve 22 on the corresponding side. Therefore, the air supply line from the other inlet port of the double check valve 12 to the air tank 6 via the air supply valve 22 is also shared by each of the front wheel side and the rear wheel side.

In the brake system of the vehicle 1, a main brake circuit, that is, a service brake circuit is formed from the pneumatic pressure line, the signal pressure line and the hydraulic pressure line, and the air supply and pneumatic pressure lines and the hydraulic pressure line are formed. An automatic braking circuit is formed. In the service brake circuit, as is well known, when the driver depresses the brake pedal 26, a signal pressure according to the depressing force and the amount of depression is supplied to the input port of each relay valve 14. The relay valve 14 is opened by the signal pressure thereof, and at the same time, the opening degree is controlled according to the magnitude of the signal pressure, whereby the air pressure path including the air supply line 24 and the supply line 13 is formed from the air tank 6. Pneumatic pressure is output via. Each double check valve 12 is a shuttle valve, and the pneumatic pipeline 8 connected to each output port is connected to the supply pipeline 1
3 and the air pressure on the high-pressure side of the outputs from the air supply line 20 are output. In this case, the output on the side of the supply pipeline 13 is selected in each double check valve 12, and the pneumatic pressure thereof is output to the air over hydraulic booster 4 via the pneumatic pipeline 8.

In the air over hydraulic booster 4, the air pressure is converted into hydraulic pressure, and the hydraulic pressure raised here drives the wheel brakes. When the driver weakens the pedal effort of the brake pedal 26 or reduces the amount of depression, the signal pressure supplied to the relay valve 14 via the brake valve 18 is reduced by that amount, and the depression of the brake pedal 26 is completed. When released, the supply of signal pressure is completely stopped. Therefore, as the signal pressure is reduced or stopped, the air pressure output to the air over hydraulic booster 4 via the relay valve 14 is also reduced or stopped.

On the other hand, in the automatic brake circuit, the automatic brake can be operated independently of the driver's braking operation. That is, each air supply valve 22 is a two-position electromagnetic directional control valve, and its solenoid is electrically connected to an electronic control unit, that is, the ECU 28. More specifically, each air supply valve 22 has an inlet port, two outlet ports, and an exhaust port, the above-described air supply line 24 is provided at the inlet port, and the air supply line 20 is provided at each outlet port. Are connected respectively. Each air supply valve 2
The switching position of No. 2 is in a non-operating state, and its inlet port is closed to allow the inflow of air pressure from the air supply line 24 and the air supply line 20.
It is a position where the output of the air pressure to the air is shut off, the two outlet ports and the exhaust port are communicated at the same time, and the inside of each air supply conduit 20 is opened to the atmosphere, that is, the shutoff position.

When each air supply valve 22 is activated in response to the operation signal from the ECU 28, the position of each air supply valve 22 makes the inlet port and the two outlet ports communicate with each other and closes the exhaust port. This is the air supply position. That is, when each air supply valve 22 is switched to the air supply position, the air pressure supplied from the air tank 6 is output, that is, air is supplied, through the air pressure path constituted by the air supply pipelines 24, 20. In this case, the output on the side of the air supply conduit 20 is output to the air over hydraulic booster 4 via the pneumatic conduit 8, and the wheel brake is driven as in the service brake circuit. Therefore, in the automatic brake circuit, separately from the braking operation by the driver, that is, the brake valve 18 is provided via the brake pedal 26.
Even if is not activated, the braking force can be generated at each wheel WFL, WFR, WRL, WRR.

The pressure regulating valve 10 is composed of a valve unit having two kinds of solenoid valves built therein, and its schematic construction is shown in FIG.
Is shown in. As shown in the figure, the pressure regulating valve 10 has three ports: an inlet port, an outlet port, and an exhaust port. Further, an electromagnetic opening / closing type holding valve 10a and an electromagnetic direction switching type exhaust valve 10b are provided therein, and each solenoid is connected to the ECU 28. Note that, in FIG. 1, for convenience of drawing, the connection between the ECU 28 and the pressure regulating valve 10 is shown by only one signal line.

The pressure regulating valve 10 is normally operated, that is, when the two solenoids are not energized, as shown in FIG.
Is in the open position, and the exhaust valve 10b is in the non-actuated position. In this state, the pressure regulating valve 10 establishes communication between its inlet port and outlet port and opens the pneumatic line 8. 1 position, that is, the ventilation position. Therefore, if the air supply valve 22 is opened when the pressure regulating valve 10 is in the first position, air pressure can be output from the air tank 6 to the air over hydraulic booster 4, that is, air can be supplied. .

On the other hand, when the ECU 28 energizes the solenoids of the holding valve 10a and the exhaust valve 10b, respectively, the holding valve 10a and the exhaust valve 10b are switched to their operating positions.
In this state, the outlet port of the pressure regulating valve 10 and the exhaust port communicate with each other. At this time, the switching position of the pressure regulating valve 10 is such that the upstream portion of the pneumatic pipe line 8, that is, the double check valve 12 side is shut off, and the downstream portion thereof,
That is, the air-over-hydraulic booster 4 side becomes the second position where it is opened to the atmosphere, that is, the exhaust position. In this state, the compressed air supplied to the air over hydraulic booster 4 is discharged from the outlet port of the pressure regulating valve 10 through the exhaust port, that is, to the atmosphere.

When only the holding valve 10a is operated during the above-mentioned air supply, that is, when the pressure adjusting valve 10 is in the air supplying position, the inlet port of the pressure adjusting valve 10 is closed and the air over hydraulic booster 4 is supplied. Further air supply is cut off.
However, since the air pressure that has already been supplied is maintained at that pressure, the switching position of the pressure adjusting valve 10 is the holding position in this state.

Therefore, in the automatic brake circuit, the ECU 2
By controlling the switching operation of the pressure regulating valve 10 while switching the air supply valve 22 on the basis of the command signal from the control valve 8, the braking air output to the air over hydraulic booster 4, that is, the above-mentioned brake drive unit is controlled. By adjusting the pressure, the automatic brake can be activated.
The operation of such an automatic brake circuit can be controlled by the ECU 28. The ECU 28 includes therein a memory circuit, a signal processing circuit, an arithmetic circuit, a determination circuit, a control circuit, an instruction circuit, and the like. The operation control of the automatic brake circuit by the ECU 28 is performed by comprehensively judging the motion state of the vehicle 1 and the driving operation of the driver. Therefore, sensor signals from various sensors are input to the ECU 28 in order to detect the motion state of the vehicle 1 during traveling and the driving operation of the driver. Among these sensors, a sensor for detecting a motion state includes a wheel speed sensor 30 for detecting the rotational speed of each wheel WFL, WFR, WRL, WRR, a longitudinal acceleration sensor 32 for detecting longitudinal acceleration applied to the vehicle body, Similarly, there are a lateral acceleration sensor 34 that detects a lateral acceleration, and a yaw rate sensor 36 that detects a yaw rate acting on the vehicle body. Further, the sensor for detecting the driving operation of the driver includes a pedal stroke sensor 38 for detecting the depression amount of the brake pedal 26, that is, a pedal stroke, a steering wheel angle sensor 42 for detecting the rotation angle of the steering wheel 40, and the like. There is.

A brake air pressure sensor 44 for detecting the air pressure output to the air over hydraulic booster 4, that is, the braking air pressure is installed in the pneumatic pressure line 8. The brake air pressure sensor 44 is provided. The sensor signal from is also input to the ECU 28.
In addition, to the electronic governor 46 that controls the fuel injection amount,
Electronic governor controller 48 that directly outputs a command signal
Is also electrically connected to the ECU 28.

As described above, the automatic brake device of this embodiment has the above-mentioned automatic brake circuit and E for controlling the automatic brake circuit.
CU28 and various electronic devices connected to it, and
It is composed of various valves. As described above, this automatic braking device automatically stabilizes the behavior of the vehicle 1 during traveling, and therefore, in actuality, the switching operation of the pressure regulating valve 10 and the air supply valve 22 is controlled respectively. By doing so, the hydraulic pressure raised in the air over hydraulic booster 4 is controlled, and as a result, each wheel WFL, WFL
The braking force generated in FR, WRL, and WRR is controlled for each.

Here, the vehicle attitude control technique for stabilizing the behavior of the vehicle includes, for example, yaw moment control,
There are automatic deceleration control and drive slip control (ASR).
Since all of these control techniques are known, the yaw moment control, the automatic deceleration control, and the drive slip control will be briefly described here. First, the yaw moment control is performed during turning, for example, between front and rear diagonal wheels (left front wheel WFL and right rear wheel WRR when turning right, right front wheel WFL and left rear wheel WRL when turning left). By giving a braking force difference, a turning yaw moment in the turning direction or a restoring yaw moment in the reverse direction of the turning is generated in the vehicle, thereby making the actual yaw movement of the vehicle coincide with the target yaw movement. Attitude control technology. The wheels to be controlled are not limited to the front and rear diagonal wheels, and may be the left front wheel WFL and the right front wheel WFR, or the left rear wheel WRL and the right rear wheel WRR.

Next, the automatic deceleration control is a limit to prevent the lateral acceleration (lateral G) applied to the vehicle from being spun, drifted out, or overturned by automatically applying braking during turning to reduce the vehicle speed. This is a vehicle speed control technology that suppresses the vehicle speed to within the lateral acceleration, that is, limits the vehicle speed to the vehicle speed limit or less at that time. This control is effective when accelerating while turning, or when the driver further turns the steering wheel while turning.

The drive slip control means that when the generated torque of the driving wheel becomes excessive at the time of starting or accelerating and the driving wheel tries to idle, the wheel is automatically braked to prevent the idling. This is a traction control technology that constantly generates optimum driving force on wheels to maintain vehicle running stability and steering performance. At this time, control for limiting the engine output may be performed. The drive slip control is effective when the road surface μ is asymmetric between the left and right drive wheels, or when the wheel load is biased to one of the left and right drive wheels during turning.

From the above, it is understood that the yaw moment control, the automatic deceleration control, and the drive slip control can all be realized by controlling the above-mentioned automatic brake circuit. Therefore, in this automatic brake device, control of the automatic brake circuit for the purpose of yaw moment control, automatic deceleration control and drive slip control is executed. Referring to FIG. 3, a main control routine of automatic brake control executed by the ECU 28 is shown, and the control procedure thereof will be described below.

First, as shown in step S10, EC
U28 reads sensor signals from the various sensors described above, that is, various detected values. Then, in the arithmetic processing shown in step S12, the motion state of the vehicle and the driving motion of the driver are calculated based on these detected values. It should be noted that the parameters indicating the motion state of the vehicle include, for example, the vehicle body speed, the slip ratio, and the center-of-gravity slip angular velocity. In addition to the steering wheel angular velocity, which is the state quantity, the parameters indicating the driving operation of the driver include a braking flag that indicates the driver's intention and a brake pedal additional depression flag.

Next, in step S14, it is determined whether or not it is necessary to start the automatic brake control. Specifically, it is determined whether the yaw moment control, the automatic deceleration control, and the drive slip control described above need to be executed. In addition, the start condition of each control is preset,
Based on the above calculation results and various detected values, the ECU 28
It is determined whether each start condition is satisfied.

If none of the yaw moment control, the automatic deceleration control, and the drive slip control satisfy the start condition, it is determined that the automatic brake control need not be started, and the determination result in step S14 Is false (No). In this case, the automatic brake control is not executed and the execution of this routine is ended. As described above, while it is determined that the yaw moment control, the automatic deceleration control, and the drive slip control are not required to be executed, the automatic brake device is not operated.

On the other hand, if the start condition is satisfied for any of the controls, it is determined that the automatic brake control needs to be started, the determination result in step S14 is true (Yes), and the process proceeds to step S16. move on. In step S16, the automatic brake device is operated to execute the control that is determined to satisfy the start condition in the determination process of step S14. Specifically, as described above, EC
U28 energizes the solenoid of the air supply valve 22 corresponding to the wheel to be controlled to switch its position to the air supply position described above.
Then, while switching the position of the pressure adjusting valve 10, the braking force of each target wheel, that is, the braking air pressure output to the air-over-hydraulic booster 4 is increased, held or reduced to be adjusted.

More specifically, when the air supply valve 22 corresponding to the target wheel is switched to the air supply position, high air pressure in the air tank 6 is supplied into the air pressure conduit 8. Here, if the pressure regulating valve 10 is in the above-described ventilation position, the braking air pressure output to the air over hydraulic booster 4 is increased,
On the other hand, if the pressure adjusting valve 10 is in the exhaust position, the braking air pressure is reduced. Actually, the actual braking air pressure is finely adjusted while finely switching the pressure adjusting valve 10 between the ventilation position and the holding position or the exhaust position and the holding position. In this case EC
The position of the pressure regulating valve 10 is switch-controlled based on the rectangular pulse signal output from U28 at a constant cycle (for example, 20 ms). The target braking air pressure for each target wheel is
The brake air pressure sensor 44 is set based on the control rules of the yaw moment control, the automatic deceleration control, and the drive slip control, and the switching control of the pressure adjusting valve 10 is performed.
Feedback control is performed so that the actual braking air pressure detected in step (1) matches the target braking air pressure.

At step S18, it is judged if the automatic brake control is to be ended. Here, the ending conditions of the yaw moment control, the automatic deceleration control, and the drive slip control are also preset, and the ECU 28 ends the control currently being executed based on the calculation result and various detected values in step S12. It is determined whether or not the condition is satisfied.

In this determination, if the ending condition for the control currently being executed is not satisfied, it is determined that the automatic brake control needs to be continued, and the determination result in step S18 is false. While the determination result in step S18 is false, the procedure from step S10 to step S16 described above is repeatedly executed, and the automatic braking device is always in the operating state.

On the other hand, if the control currently being executed satisfies the termination condition, it is determined that the automatic brake control need not be continued any longer. In addition, as described above, the automatic brake device can operate even if the driver does not step on the brake pedal 26.
That is, the device automatically applies a brake independently of the driver's brake operation, but if the driver depresses the brake pedal 26, it can be determined that the driver intends to apply the brake. Therefore, in the determination in step S18, in addition to the case where the ending condition of the control currently being executed is satisfied, the automatic brake control is forcibly ended even when the driver depresses the brake pedal during the control. Therefore, in these cases, the determination result in step S18 is true, and the process proceeds to step S20.

Referring to FIG. 4, the control end processing routine of step S20 is shown in detail. This control end processing routine is a processing for actually stopping the operation of the air supply valve 22 and the pressure adjusting valve 10 of the automatic brake circuit described above, and the procedure thereof will be described below. In step S22, a command to end the above automatic brake control is issued. Note that this control end command is simply the ECU
This is a command formed in 28.

In step S24, it is determined whether or not the main control routine that is currently being executed is in the previous control cycle at the automatic brake control end stage, that is, in the final routine.
Even if the control end is determined in step S18 and the control end command is issued in step S22 of the control end processing routine of FIG. 4, the automatic brake device cannot be immediately stopped at that point. That is, it is necessary to surely perform the above-described air pressure discharge processing in the automatic brake circuit before stopping the automatic brake device and adjust the condition for the service brake circuit to function effectively. Therefore, it is determined whether or not the main control routine is executing the automatic brake control, that is, the final routine one control cycle before for proceeding to the operation of ending the vehicle attitude control.

Specifically, in the final routine of the automatic brake control, all the pressure adjusting valves 10 corresponding to the wheels to be controlled are switched to the exhaust position. As a result, the output of air pressure from each air pressure pipeline 8 to the air over hydraulic booster 4 is cut off, and the air pressure output to each air over hydraulic booster 4 is reduced by the exhaust valve 1 of the pressure control valve 10.
It is discharged from the exhaust port 0b. As a result, the hydraulic pressure raised in each wheel cylinder 2 drops, and all automatic braking is released. The switching position of the pressure adjusting valve 10 at this time is not limited to the exhaust position described above, and when the air pressure output to the air over hydraulic booster 4 is sufficiently low, or when it is desired to maintain the braking force due to the control request. In this case, it is possible to switch to the holding position.

If the above final routine is not yet executed in the main control routine, the determination result in step S24 becomes false, the control termination processing routine of this time is terminated, and the main control routine of FIG. Step S10 to Step S18, and Step S
After step 22, the next step S24 is executed. Therefore, the above procedure is repeatedly executed until the above-mentioned final routine is executed in the main control routine.

If the final routine is executed in the main control routine, the determination result in step S24 becomes true,
Then, the process proceeds to step S26. In step S26, the air supply valve 22 corresponding to the control target wheel is returned to the shutoff position. As a result, the inflow of air pressure from the air tank 6 to each air supply conduit 20 is blocked. Then, at this time, the air pressure raised in each air supply conduit 20 is exhausted from the outlet port of the air supply valve 22 via the exhaust port.

At this time, as described above, each pressure regulating valve 1
Since 0 has already been switched to the exhaust position, each pneumatic line 8
The air pressure raised therein also flows into the air supply line 20 via the double check valve 12 and is exhausted via the exhaust port of the air supply valve 22. During this time, the double check valve 12 communicates between the outlet port and the inlet port on the high pressure side, so that the air pressure in the air pressure conduit 8 can flow back into the air supply conduit 20. When the pressures in the air supply line 20 and the supply line 13 are balanced, the double check valve 12 returns to the neutral position.

Meanwhile, in step S26, the ECU 28
The time difference timer in is set to start its operation. At this time, the timer value is set in the time difference timer, and at the same time, the measurement of the elapsed time after that is started. The time difference timer is for measuring the delay time until the pressure control valve 10 is switched to the ventilation position after the air supply valve 22 is switched to the shutoff position and the timer value is set. The timer value at this time, that is, the delay time is set to a different value depending on the difference in the control end determination method in step S18. That is, when the driver normally satisfies the control termination condition without depressing the brake pedal 26, the delay time is that the air pressure in the upstream portion of each pneumatic pipeline 8 and each intake pipeline 20 is equal to the intake valve 22. Is set to the time required for complete discharge.

On the other hand, the driver operates the brake pedal 26
When the control is forcibly ended due to the depression of, the delay time is such that the air pressure of the service brake circuit reaches each pressure regulating valve 10 from each brake valve 14 via the supply pipeline 13 and the pneumatic pipeline 8. It is set to the time required for the pneumatic pressure here to rise sufficiently. It should be noted that these delay times can be set in advance, respectively, and the former delay time, that is, the delay time at the time of normal termination, is based on the pressure detected by each brake air pressure sensor 44, and the delay time is adjusted accordingly. It can also be calculated and set. In this case, mechanical conditions such as the entire length of the air passage including the pneumatic line 8, the double check valve 12, the air supply line 20 and the air supply valve 22 and the flow resistance thereof, and the exhaust efficiency of the air supply valve 22,
It is properly calculated based on the relationship between the physical properties of air, which is a fluid, and the pressure.

In step S30, it is determined whether or not the value of the time difference timer has reached the above delay time. If the delay time has not elapsed since the time difference timer was set, it is determined that the discharge of the air pressure in each pneumatic line 8 and the air supply line 20 is not yet completed, and the determination result in step S30 Becomes false, and step S30 is executed again.

While the determination result in step S30 is false, the execution of step S30 is repeated. If the delay time elapses after the time difference timer is set, it can be determined that the air pressure in each pneumatic pipeline 8 and the air supply pipeline 20 has been completely discharged, and the determination result in step S30 becomes true, and the next To step S32. In step S32,
Each pressure control valve 10 corresponding to the control target wheel is turned off, that is, the air supply valve 10a and the exhaust valve 10b are both switched to the vent position where they are inactive. Therefore, after the automatic brake control end command is issued, the pneumatic pipe line 8 corresponding to the wheel to be controlled is not opened until step S32 is executed. In other words, the pneumatic pipeline 8 is opened within the delay time set by the above-mentioned time difference timer, that is, the residual pressure is present in the pneumatic pipeline 8 and the air supply pipeline 20, and the residual pressure is exceeded. Hydraulic booster 4
As a result, the wheel brake will not be driven undesirably.

When the execution of the above control end processing routine is completed, the main control routine of FIG. 3 is repeatedly executed again. Until the next automatic brake control is executed, the air supply valves 22 and the pressure control valves 10 are held at the shut-off position or the ventilation position, so that the service brake circuit can be operated during this time. According to the automatic brake device of this embodiment, at the normal end of the automatic brake control,
By executing the above-described control end processing routine, it is possible to reliably discharge the air pressure in each of the air pressure conduits 8 and the air supply conduits 20 and end the control. Therefore, the brake drive unit can be connected to the main service brake circuit after the automatic brake is smoothly released.

Further, when the driver depresses the brake pedal 26 to forcibly terminate the control during the automatic brake control, if the time required to raise the sufficient pneumatic pressure in the service brake circuit elapses, the pneumatic lines are immediately released. Since 8 is opened, the operation of the wheel brake will not be inadvertently delayed with respect to the depression of the brake pedal 26. Therefore, the safety of avoiding an emergency collision due to sudden braking can be ensured.

The automatic brake device of this embodiment is
It can be directly applied to a vehicle that employs an anti-skid brake system, so-called ABS. That is, each pressure regulating valve 10 can be used for controlling the pressure of the ABS on the one hand and for controlling the pressure of the above-mentioned automatic brake on the other hand. Therefore, even in a vehicle to which the ABS is applied, it is not necessary to provide a separate pressure adjusting valve for the automatic brake circuit, and the pressure adjusting valve 1 can be used in the service brake circuit and the automatic brake circuit.
The number of parts can be reduced by sharing 0.

The present invention is not limited to the above embodiments. For example, the brake system of the vehicle 1 is not limited to the air over hydraulic brake, and may be a full air brake. In this case, all the hydraulic lines from the air over hydraulic booster 4 serving as the brake drive unit are replaced with pneumatic lines, and the wheel brakes are driven by the brake chamber.

By the way, in this automatic brake device, E
The CU 28 (control means) sets the stop time of the automatic brake to the time when the driver operates the brake.
When the automatic brake is stopped, 28 can simultaneously return the air supply valve to the shutoff position and switch the pressure control valve to the ventilation position. The processing procedure in this case is such that, when the driver depresses the brake pedal 26 to forcibly terminate the automatic brake control in the control termination processing routine of FIG. 4, the processing of step S28 is unnecessary, and steps S26 and S30 are performed in parallel. Will be executed.

Therefore, as a result of the air supply valve 22 and the pressure adjusting valve 10 being simultaneously switched to the shut-off position or the ventilation position, respectively, the air pressure raised in the pneumatic pressure line 8 and the air supply line 20 as described above is reduced. While being discharged from the exhaust port of the air supply valve 22 on the one hand, it is output to the air over hydraulic booster 4 on the other hand. Then, if the air pressure output via the relay valve 14 rises until it balances with the residual pressure in the air supply line 20, this air pressure is selected by the double check valve 12 and flows into the air pressure line 8. . Therefore,
If the driver depresses the brake pedal 26, the automatic braking is immediately stopped without waiting for the pneumatic pressure in the pneumatic line 8 to be completely discharged, and at the same time, the braking force by the service brake can be generated. It should be noted that this case can be applied only when the driver depresses the brake pedal 26 during the operation of the automatic brake, and when the automatic brake is stopped by satisfying the ending condition of the automatic brake control, the above-described embodiment is used. The control end processing routine is executed.

[0054]

As described above, according to the automatic brake device for a vehicle of the first aspect, when the automatic brake is stopped, the braking force can be reliably released and the control can be ended. Therefore, the behavior of the vehicle does not become unstable at the end of the automatic brake control, and stable vehicle attitude control that does not make the driver feel uncomfortable or anxious can be performed.

According to the vehicle automatic brake device of the second aspect, even if the automatic brake is in operation, if the driver operates the brake, the automatic brake is immediately stopped, and the main brake is quickly switched to. It can be performed. Therefore, the responsiveness to the brake operation by the driver is not lowered, and the safety in emergency such as sudden braking is not impaired.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a brake system of a vehicle 1.

FIG. 2 is a diagram showing a detailed configuration of a pressure regulating valve 10.

FIG. 3 is a flowchart showing a main control routine of the automatic braking device.

FIG. 4 is a flowchart showing a control end processing routine of the automatic brake device.

[Explanation of symbols]

2 wheel cylinder 3 hydraulic lines 4 Air over hydraulic booster 6 Air tank (pneumatic source) 8 pneumatic lines (3rd pneumatic line) 10 Pressure control valve 12 double check valves 13 Supply pipeline (1st pneumatic path) 14 Relay valve 20 Air supply line (second pneumatic line) 22 Air supply valve 24 supply lines 28 ECU (control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-50-55768 (JP, A) JP-A-10-181575 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T 7/12 B60T 13/00

Claims (2)

(57) [Claims] 1. A first air-pressure source, which receives air pressure from an air-pressure source, and directs air pressure corresponding to a driver's operation toward a brake drive unit.
A main brake pressure supply means for outputting via an air pressure path and an air pressure supply from an air pressure source, and outputs the air pressure of this air pressure source toward the brake drive unit via a second air pressure path. And an air supply valve having a shutoff position for shutting off the output of pneumatic pressure to the second pneumatic path and exhausting the air in the second pneumatic path, and the first and second pneumatic pressures. A double check valve that outputs a high-pressure side air pressure of the outputs from the main brake pressure supply means and the air supply valve through an output port; and an output port of the double check valve and the brake drive. A third pneumatic path connecting between the unit and a first position provided on the third pneumatic path and opening the third pneumatic path, and an upstream portion of the third pneumatic path on the double check valve side. And the third empty space on the side of the brake drive unit. A pressure control valve having at least a second position for opening the downstream portion of the path to the atmosphere, and switching the air supply valve to the air supply position and switching the operation of the pressure control valve under a predetermined traveling condition of the vehicle. Control and
A control means for adjusting the braking air pressure of the brake drive unit to operate the automatic brake, wherein the control means, when stopping the automatic brake, elapses a predetermined time after returning the air supply valve to the cutoff position. An automatic brake device for a vehicle, characterized in that the pressure regulating valve is switched to the first position and operated later. 2. The control means sets a stop time of the automatic brake at a brake operation time point by a driver, and an air pressure output from the main brake pressure output means is applied to the pressure control valve for the predetermined time. The automatic braking device for a vehicle according to claim 1, wherein the automatic braking device is set within a time until reaching the reaching point.