JPH10244932A - Device for coping with flat tire on vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a device for coping with the flat tire on an vehicle that safety countermeasures can be taken if tire inflation pressure drops suddenly. SOLUTION: The wheel speed of wheels 2L, 2R, 3L, 3R is detected by wheel speed detecting sensors 55 to 58, while the steering state of a steering wheel 8 is detected by a steering angle sensor 59. In addition, the yaw rate which occurs in the vehicle is detected by a yaw rate sensor 63. When a controller 65 detects that the quantity of state of one wheel is differs from that of the rest of the wheels by more than a prescribed quantity and moreover that the yaw rate which is detected at this time exceeds the reference value corresponding to the steering state at that time, the controller 65 judges that the tire in consideration is punctured and actuates a braking device so as to execute automatic braking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for dealing with a tire puncture of a vehicle, which effectively deals with a puncture of a tire of a vehicle during running.

[0002]

2. Description of the Related Art Tires support the load of a vehicle and reduce the impact from the road surface, transmit engine power, braking force, steering force, etc. to the road surface, and are extremely important functions for maintaining vehicle motion. It has. The tire exhibits its function by rolling on the road and exchanging force with the road surface, that is, its performance is exhibited during running of the vehicle.
Therefore, if an abnormality occurs in the tires while the vehicle is running,
In particular, when an abnormality occurs in the tires of the steered wheels during high-speed running, the steering is immediately seriously affected.

[0003] An example of such a tire abnormality is puncture. The puncture includes a so-called normal puncture in which the inside air gradually escapes and the air pressure decreases, and a so-called burst in which the tire bursts and the inside air instantaneously escapes and the air pressure suddenly decreases. In particular, in a large vehicle such as a truck, the air pressure of the tire is extremely high, and there is a possibility that a burst may occur due to an overload or the like.

When a tire puncture occurs during traveling, the driver needs to take prompt measures, for example, apply a braking force to stop the vehicle. while doing,
When a tire burst occurs while driving, it takes time for the driver to detect the tire abnormality due to vehicle behavior, steering abnormality, etc., and it is difficult to respond appropriately after detecting the abnormality In many cases. In particular, there are many drivers who avoid the vehicle only by operating the steering wheel in an instant, and the avoidance due to the vehicle deceleration tends to be delayed. Further, it is often difficult to issue a warning for notifying the surrounding vehicles of the abnormality.

[0005] As an apparatus for judging an abnormality of the tire pressure of a vehicle, for example, there is an apparatus for judging the tire pressure of a vehicle disclosed in Japanese Patent Application Laid-Open No. H5-213019. This determination device compares the appropriate wheel speed difference calculated by the wheel speed difference calculation means with the difference between the wheel speeds of the left and right front wheels detected by the wheel speed difference detection means, and determines when these differences exceed a predetermined value. A comparison means for determining that the tire air pressure is in a reduced pressure state is provided to determine a decrease in wheel air pressure.

[0006]

However, the conventional judging device for judging a decrease in the air pressure of a wheel has a relatively safe air pressure decrease state and a sharp air pressure decrease state such as a tire burst only in the same dimension. It is not possible to make a determination, and in particular, it is not possible to accurately and quickly determine an extremely abnormal situation such as a tire burst.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an apparatus for dealing with a puncture of a vehicle tire, in which safety measures are taken when the tire pressure suddenly drops. .

[0008]

According to the present invention, there is provided a wheel speed detecting means for detecting a wheel speed of each of a plurality of wheels, and a steering state detecting means for detecting a steering state of a steering wheel. And yaw rate detection means for detecting a yaw rate generated in the vehicle, safety measure means for taking a safety measure for the vehicle, and presence of a wheel whose state quantity related to the wheel speed differs by at least a predetermined amount from other wheels. When the detected yaw rate is detected to be equal to or more than a reference value corresponding to the steering state, the control means is provided for activating the safety measure means.

The wheel speed detecting means detects each wheel speed of a plurality of wheels of the vehicle, the steering state detecting means detects the steering state of the steering wheel, and the yaw rate detecting means detects the yaw rate generated in the vehicle. Then, it is detected that the state quantity related to the wheel speed of one wheel is different from the state quantity related to the wheel speed of the other wheel by a predetermined amount or more,
When it is detected that the yaw rate (vehicle behavior) detected at this time is equal to or greater than a reference value corresponding to the steering state, it is determined that the tire is punctured, and the safety measure is activated. For example, processes such as activating an automatic brake, reducing the engine output to decelerate the vehicle, and issuing an alarm to notify the surrounding vehicles of an abnormality are performed simultaneously or stepwise according to the situation. By determining a puncture by combining a situation in which the state quantity related to the wheel speed is different from the other wheels by a predetermined amount or more and a situation in which a yaw rate equal to or more than the reference value corresponding to the steering state is determined, a tire burst or the like is determined. Detect abnormal conditions quickly and take safety measures under abnormal conditions.

[0010]

Embodiments of the present invention will be described below with reference to embodiments. FIG. 1 shows a configuration of a vehicle to which the present invention is applied, and particularly shows a configuration of a brake control device. In FIG. 1, the vehicle 1 has a front one axis and a rear two axes (neither is shown), and among the two rear axes, a front axis is a drive axis and a rear axis is a driven axis. The wheel cylinders 5L, 5R of the left and right front wheels 2L, 2R are connected to air over hydraulic boosters 15, 16 via braking pipes (oil passages) 11, 12. Left and right rear wheels of the drive shaft (hereinafter referred to as "drive wheels")
3L, 3R wheel cylinders 6L, 6R, and right and left rear wheels of the driven shaft (hereinafter referred to as “driven wheels”) 4
The wheel cylinders 7L and 7R of L and 4R are connected to air over hydraulic boosters 17 and 18 via braking pipes (oil passages) 13 and 14.

Air over hydraulic booster 15 ~
Numeral 18 converts the input air pressure into a hydraulic pressure and outputs a braking hydraulic pressure to each of the wheel cylinders 5L, 5R, 6L, 6R, 7L, 7R. A pressure for adjusting the braking pressure is provided on the input side. The control valves 25 to 28 are connected to discharge ports of double check valves (shuttle valves) 31 to 34. One input port of each of the double check valves 31 and 32 is connected to a discharge port of a relay valve 35, and the other input port is connected to each discharge port of an automatic brake pressure supply valve (air supply valve) 37. I have. One input port of each of the double check valves 33 and 34 is
The other input port is connected to a discharge port of a relay valve 36, and the other input port is connected to each discharge port of an automatic brake pressure supply valve (air supply valve) 38. The double check valves 31 to 34 output from the discharge port a pressure corresponding to the higher one of the pressures input from the two input ports.

The control ports of the relay valves 35 and 36 are connected to brake valves 45a and 45b of a brake pedal 45 via air passages 41 and 42, respectively.
8 is connected. Air tanks 47 and 48 are directly connected to the input ports of the relay valves 35 and 36, and the relay valves 35 and 36 are connected to the brake valves 45.
The opening degree is controlled using the pressure according to the operation state of the brake pedal 45 input from a and 45b as a signal pressure, and the pressure is output according to the brake pedal operation. The input ports of the automatic brake pressure supply valves 37, 38 are connected to air tanks 47, 48 through air passages 43, 44.
When the valve is opened, a pressure corresponding to the internal pressure of the air links 47 and 4 is output.

Air over hydraulic booster 15 ~
Pressure sensors 51 to 54 for detecting pneumatic pressure (braking pressure) to be supplied to the air overhydraulic boosters 15 to 18 are connected to the air passages between the pressure control valves 18 and the pressure control valves 25 to 28. Wheel speed sensors 55 and 56 are provided near the left and right front wheels 2L and 2R, wheel speed sensors 57 and 58 are provided near the left and right drive wheels 3L and 3R, and a steering angle sensor 59 is provided for the steering wheel 8. However, the brake pedal 45 is provided with a brake pedal stroke sensor 60 for detecting the amount of depression of the pedal. The brake pedal stroke sensor 60 has a pedal switch function that is turned on when the brake pedal 45 is depressed.

A longitudinal acceleration sensor 61 for detecting the longitudinal acceleration of the vehicle body, a lateral acceleration sensor 62 for detecting the lateral (left / right) acceleration of the vehicle body are provided at predetermined positions of the vehicle.
And a yaw rate sensor 63 for detecting a rate generated in the vehicle body. These pressure sensors 51 to
54, the wheel speed sensors 55 to 58, the steering angle sensor 59, the brake pedal stroke sensor 60, the longitudinal acceleration sensor 61, the lateral acceleration sensor 62, and the yaw rate sensor 63 are input to the control device 65 as control means. . The controller 65 controls the pressure control valves 25 to 28 and the automatic brake pressure supply valves 37 and 38 based on signals input from these sensors to control the braking force applied to each wheel. In this embodiment, the pressure control valve 25
28, the automatic brake pressure supply valves 37 and 38 constitute safety measures.

The operation will be described below. First, the normal brake control in which the driver depresses the brake pedal 45 to operate the main brake will be described. Brake pedal 4
When the brake pedal 5 is depressed, the brake valves 45a and 45b are opened, and the braking pressure is supplied from the air tanks 47 and 48 to the relay valves 35 and 36 so that these relay valves 3
Valves 5 and 36 are opened. When the relay valves 35 and 36 are opened, the air passages 43 and 4
4, relay valve 35, 36, double check valve 3
Brake pedal 45 to air over hydraulic boosters 15 to 18 in the route of pressure control valves 25 to 28
Is supplied in accordance with the amount of depression of the brake pedal. The air over hydraulic boosters 15 to 18 are provided with pressure control valves 25 to
A hydraulic pressure is generated in accordance with the braking pressure supplied from 28 to drive the wheel cylinders 5L, 5R, 6L, 7L, 6R, 7R, and the front wheels 2L, 2R, the driving wheels 3L, 3R, and the driven wheels 4
A braking force is applied to L and 4R. Thus, during normal braking, the braking force corresponding to the amount of depression of the brake pedal 45 is applied to the front wheels 2L, 2R, the driving wheels 3L, 3R, and the driven wheels 4
Generated on all wheels L and 4R.

By the way, when the brake pedal 45 is greatly depressed and the brakes are suddenly applied during slipping on a slippery road surface or high-speed running, the wheels are slipped. Control device 6
5 executes anti-skid control when it detects that a slip has occurred based on signals from the wheel speed sensors 55 to 58. At the time of the anti-skid control, the slip ratio of each wheel is calculated, and each pressure control valve 2 is controlled according to the slip ratio.
By controlling 5-28, the braking force of each wheel is appropriately controlled to avoid locking of the wheel.

The brake control device has a function of automatically operating the brake independently of the operation of the brake pedal 45. When the automatic brake is operated, the automatic brake pressure supply valves 37 and 38 are opened. It is made to valve. When the automatic brake pressure supply valves 37 and 38 are opened, braking pressure is applied to the pressure control valves 25 to 28 from the air tanks 47 and 48 via the air passages 43 and 44, the automatic brake pressure supply valves 37 and 38, and the double check valves 31 to 34. This braking pressure is adjusted to the target braking pressure by the pressure control valves 25 to 28, and is supplied to the air over hydraulic boosters 15 to 18. The air-over-hydraulic boosters 15 to 18 generate a hydraulic pressure according to the braking pressure supplied from the pressure control valves 25 to 28 and apply a braking force to the corresponding wheels according to the target braking pressure. The braking pressure applied to the air overhydraulic boosters 15 to 18 is detected by pressure sensors 51 to 54, respectively, and is input to the control device 65 as a feedback signal.

Such an automatic brake operation functions during yaw moment control or automatic deceleration control. Control device 6
5 is a target yaw rate calculated from the steering angle and the vehicle speed;
When the deviation from the actual yaw rate detected by the yaw rate sensor 63 exceeds a predetermined value, yaw moment control is executed, and a braking force difference is applied between the left and right wheels to control the yaw moment generated in the vehicle so that the deviation decreases. I do. In addition, the control device 65 executes an automatic deceleration control for automatically decelerating the vehicle so that the vehicle speed or the lateral acceleration is within a limit value when the vehicle speed or the lateral acceleration during the turning of the vehicle is too high.

Further, the control device 65 activates the automatic brake also when a puncture of the vehicle is detected. Referring to a flowchart shown in FIG. The measures taken at that time will be described. It is assumed that one wheel, for example, the left front wheel 2L bursts during traveling of the vehicle. When the front wheel 2L bursts, the wheel speed drops abruptly by the front wheel 2L. At this time, if the driver does not operate the steering wheel, the vehicle is tilted toward the front wheel 2L and the yaw rate is in spite of the neutral steering. Greatly occurs, and the behavior of the vehicle 1 is disturbed. The yaw rate sensor 63 quickly detects disturbance in the behavior of the vehicle and outputs a signal corresponding to the yaw rate. Therefore, if such a situation is detected, a sudden vehicle puncture state such as a burst can be detected.

FIG. 2 shows a control process based on such an idea.
It is more concrete. The control device 65 is provided with each sensor
Signal from each wheel, each wheel speed (Vw), vehicle speed
(V), yaw rate (γ), operation of brake pedal 45
The state and the steering angle (δH) are detected (Step S1), and each vehicle is detected.
Wheels, ie, left and right front wheels 2L, 2R and left and right drive wheels 3L,
The 3R acceleration is calculated (step S2), and the vehicle speed and the steering angle are calculated.
And the reference yaw rate (γ ^*) (Step
S3). Next, the control device 65 determines the current vehicle speed (V).
Determines whether the vehicle speed is higher than the constant vehicle speed (for example, 10 km / h)
(Step S4), when the vehicle speed is lower than the predetermined vehicle speed
It returns to step S1. The determination of the vehicle speed condition in step S4
Being different, the vehicle drive due to the drive slip
Is prevented from being erroneously detected.

When it is determined in step S4 that the vehicle speed is equal to or higher than the predetermined vehicle speed, the control device 65 determines whether the brake pedal 45 is being operated (step S5).
When the brake pedal 45 is depressed, the process returns to step S1, and when the brake pedal 45 is not depressed, the condition that the deviation between one wheel speed and the average wheel speed of the other three wheels is equal to or more than a predetermined value B is satisfied. It is determined whether there is a wheel that satisfies the condition (for example, whether the deviation between the wheel speed of the front wheel 2L and the average wheel speed of the front wheel 2R, the driving wheels 3L, and 3R is equal to or more than a predetermined value B) (step). S
6). Since the determination for the tire puncture is performed during non-braking, it is determined in step S5 whether the brake pedal 45 is being operated or not, thereby erroneously detecting the disturbance of the vehicle behavior due to the wheel lock on the split road or the like. Disappears.

In step S6, if the condition that the absolute value of the deviation between one wheel speed and the average wheel speed of the other three wheels is not less than a predetermined value B is not satisfied, the process returns to step S1, and if there is a wheel satisfying the condition. Acceleration of one wheel and the other three
Whether any of the wheels satisfies the condition that the deviation from the average acceleration of the wheels is equal to or greater than a predetermined value C (for example, the absolute value of the deviation between the acceleration of the front wheel 2L and the average acceleration of the front wheel 2R and the driving wheels 3L and 3R is a predetermined value) It is determined whether or not a condition of C or more is satisfied) (step S7). The determination in step S6 and step S7 is performed for each wheel. In addition, these steps S6
The reason for taking the absolute value of the deviation in step S7 is that the wheel speed is considered to be high when the vehicle runs on a wheel during a burst, and the wheel speed is low when the wheel is broken.

In step S7, if there is no wheel that satisfies the condition that the deviation between the acceleration of one wheel and the average acceleration of the other three wheels is equal to or greater than a predetermined value C, the process returns to step S1, and if the condition is satisfied, the detected yaw rate and step S3
The absolute value of the deviation from the reference yaw rate calculated by
It is determined whether the condition that satisfies the above condition (in this case, γ ^* + D corresponds to the reference value) is satisfied (step S8). If the condition is not satisfied, the process returns to step S1, and if the condition is satisfied, a safety measure is executed ( Step S9). As this safety measure, for example, the above-described automatic braking is executed.

In the above control, the determination of the vehicle speed in step S5 may be omitted. Step S6
Although the determination in step S7 is made for each wheel, it may be a deviation between the left and right sides (front wheels 2L and 2R, drive wheels 3L and 3R). Although the absolute value of the deviation is used in the discrimination, the wheel speed of one of the wheels (the front wheel 2L, the driving wheel 3L) is adjusted to the corresponding other wheel (the front wheel 2R,
The determination may be made only on either the lower side or the increase side of the wheel speed of the drive wheel 3R).

In this embodiment, a method using the wheel speed (step S6) and a method using the wheel acceleration (step S7) are employed as specific methods for detecting a rapid change in the wheel speed. However, any one of the methods (determination of either step S6 or step S7) may be used. In step S8, the absolute value of the deviation between the actual yaw rate and the reference yaw rate is taken, but it is also possible to determine only the case where the actual yaw rate is excessive without taking the absolute value. Further, the reference yaw rate (γ ^* ) may be set to a fixed value so that the determination in step S8 is performed only when the steering angle is in the small steering angle area. In this case, the calculation in step S3 is unnecessary.

Further, in step S9, in addition to executing automatic braking as a safety measure, an alarm device in the cab is activated to issue an alarm to notify the driver, and the engine control device suppresses the engine output (for example, the electronic governor 9 to reduce the engine output by reducing the fuel injection amount) to reduce the vehicle speed, and to activate an outside warning device (flashing of warning lamps, etc.) to issue an alarm to notify other nearby vehicles of an abnormality. May be adopted.

[0027]

As described above, according to the present invention, a situation where the state quantity related to the wheel speed differs from the other wheels by a predetermined amount or more and a situation where the yaw rate exceeding the reference value corresponding to the steering state occurs. By determining puncture in combination,
An abnormal situation such as a tire burst can be detected reliably and quickly, and safety measures can be taken reliably under the abnormal situation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a vehicle including a vehicular tire puncture response device according to the present invention.

FIG. 2 is a flowchart showing a detection method when a tire of the vehicle shown in FIG. 1 is punctured, and a procedure for dealing with the puncture.

[Explanation of symbols]

Reference Signs List 1 vehicle 2L, 2R front wheel 3L, 3R driving wheel 4L, 4R driven wheel 5L, 5R, 6L, 6R, 7L, 7R wheel cylinder 8 steering wheel 9 electronic governor 11-14 brake pipe (oil passage) 15-18 air overhydro Rick booster 25-28 Pressure control valve 31-34 Double check valve 35,36 Relay valve 37,38 Automatic brake pressure supply valve 41-44,76,77 Air passage 45 Brake pedal 47,48 Air tank 51-54 Pressure sensor 55 58 wheel speed sensor 59 steering angle sensor 60 brake pedal stroke sensor 61 longitudinal acceleration sensor 62 lateral acceleration sensor 63 yaw rate sensor 65 control device

Claims (1)

[Claims] 1. A wheel speed detecting means for detecting wheel speeds of a plurality of wheels, a steering state detecting means for detecting a steering state of a steering wheel, a yaw rate detecting means for detecting a yaw rate generated in a vehicle, and the vehicle, Safety measure means for taking safety measures, and the presence of a wheel whose state quantity related to the wheel speed is different from the other wheels by a predetermined amount or more is detected, and the detected yaw rate is equal to or more than a reference value corresponding to the steering state. And control means for activating the safety measure means when it is detected that the vehicle is tire punctured.