JP3794091B2 - Vehicle tire puncture countermeasure device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle tire puncture countermeasure device that effectively copes with a case where a tire of a vehicle punctures during traveling.
[0002]
[Prior art]
The tire supports the load of the vehicle to alleviate the impact from the road surface, and transmits a power of the engine, a braking force, a steering force, etc. to the road surface, and has a very important function for maintaining the motion of the vehicle. The tire exerts its function by rolling on the road and exchanging force with the road surface, that is, its performance is exhibited while the vehicle is running. Therefore, if an abnormality occurs in the tire during traveling of the vehicle, particularly if an abnormality occurs in the tire of the steered wheel during high-speed traveling, the steering is immediately affected significantly.
[0003]
There is a puncture as such a tire abnormality. The puncture includes a so-called normal puncture in which the internal air gradually escapes and the air pressure decreases, and a so-called burst in which the tire bursts and the internal air instantaneously escapes and the air pressure rapidly decreases. In particular, in large vehicles such as trucks, the tire air pressure is extremely high, and there is a risk of bursting due to overloading or the like.
[0004]
When tire puncture occurs during traveling, the driver needs to deal with it quickly, for example, by applying braking force and stopping the vehicle. However, if a tire burst occurs during driving, it takes time for the driver to detect a tire abnormality due to vehicle behavior, steering abnormality, etc., and take appropriate measures after detecting the abnormality. Is often difficult. In particular, in the case of a saddle, there are many drivers who avoid the vehicle only by operating the steering wheel. Also, it is often difficult to issue an alarm for notifying surrounding vehicles of an abnormality.
[0005]
As an apparatus for determining an abnormality in the tire pressure of a vehicle, for example, there is a tire pressure determination apparatus for a vehicle disclosed in Japanese Patent Laid-Open No. 5-213019. This determination device compares the appropriate wheel speed difference calculated by the wheel speed difference calculating means with the difference between the wheel speeds of the left and right front wheels detected by the wheel speed difference detecting means, and when these differences exceed a predetermined value. Comparing means for determining that the tire air pressure is reduced is provided to determine a decrease in wheel air pressure.
[0006]
[Problems to be solved by the invention]
However, the conventional determination device for determining a decrease in the air pressure of the wheel can determine a relatively safe air pressure decrease state and a sudden air pressure decrease state such as during a tire burst only in the same dimension. An extremely abnormal situation such as a burst cannot be accurately and quickly determined.
[0007]
The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicle tire puncture countermeasure device that takes safety measures when the tire air pressure rapidly decreases.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, wheel speed detecting means for detecting wheel speeds of a plurality of wheels, braking state determining means for determining whether or not a brake pedal is being operated, and a steering wheel The steering state detecting means for detecting the steering state of the vehicle, the yaw rate detecting means for detecting the yaw rate generated in the vehicle, the safety means for taking safety measures for the vehicle, and the brake pedal is not being operated by the braking state determining means and when it is judged a state quantity relating to the wheel speed is detected to be present more than a predetermined amount different wheel than the other wheels, the yaw rate and the difference between the reference yaw rate obtained from steering condition being and detected When it is detected that the absolute value is greater than or equal to a predetermined value , the control means is configured to activate the safety measure means.
[0009]
The wheel speed detecting means detects each wheel speed of a plurality of wheels of the vehicle, the braking state determining means determines whether or not the brake pedal is being operated, and the steering state detecting means detects the steering state of the steering wheel. The yaw rate generated in the vehicle is detected by the yaw rate detecting means. When it is determined that the brake pedal is not being operated, 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 the absolute value of the difference between the reference yaw rate obtained from steering state and the yaw rate (vehicle behavior) detected is detected to be equal to or greater than a predetermined value when, it is determined that the tire is punctured, safety measures Activate the means. For example, processing such as operating an automatic brake, decelerating the vehicle by reducing the engine output, issuing an alarm and notifying the surrounding vehicle of an abnormality is performed simultaneously or stepwise depending on the situation. As described above, the yaw rate in which the absolute value of the deviation between the reference yaw rate obtained from the steering state and the situation in which the state quantity related to the wheel speed differs from the other wheels by a predetermined amount or more, the situation in which the braking state is not braked, and the steering state By detecting the puncture in combination with the situation where the problem occurs, an abnormal situation such as a tire burst is quickly detected, and safety measures are taken under the abnormal situation. Further, by taking safety measures only during non-braking, it is possible to prevent erroneous detection of vehicle behavior disturbance due to wheel lock on a split road or the like.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described by way of examples.
FIG. 1 shows the configuration of a vehicle to which the present invention is applied, and particularly shows the configuration of a brake control device. In FIG. 1, the vehicle 1 has a front 1 axis and a rear 2 axis (both not shown), and among the rear 2 axes, the front axis is a drive axis and the rear axis is a driven axis. The wheel cylinders 5L and 5R of the left and right front wheels 2L and 2R are connected to air over hydraulic boosters 15 and 16 via brake pipes (oil passages) 11 and 12, respectively. Left and right rear wheels (hereinafter referred to as “driving wheels”) 3L and 3R wheel cylinders 6L and 6R of the driving shaft, and left and right rear wheels (hereinafter referred to as “driven wheels”) 4L and 4R wheel cylinders 7L of the driven shaft. , 7R are connected to air over hydraulic boosters 17 and 18 via brake pipes (oil passages) 13 and 14, respectively.
[0011]
The air over hydraulic boosters 15 to 18 convert the input air pressure into hydraulic pressure and output the braking hydraulic pressure to the wheel cylinders 5L, 5R, 6L, 6R, 7L, and 7R, and the input side performs braking. It is connected to discharge ports of double check valves (shuttle valves) 31 to 34 via pressure control valves 25 to 28 for adjusting the pressure. One input port of each of the double check valves 31 and 32 is connected to the discharge port of the relay valve 35, and the other input port is connected to each discharge port of the automatic brake pressure supply valve (supply valve) 37. Yes. One input port of each of the double check valves 33 and 34 is connected to the discharge port of the relay valve 36, and the other input port is connected to each discharge port of the automatic brake pressure supply valve (supply valve) 38. Yes. And these double check valves 31-34 output the pressure according to the higher one of the pressures input from two input ports from a discharge port.
[0012]
The control ports of the relay valves 35 and 36 are connected to the brake valves 45a and 45b of the brake pedal 45 via the air passages 41 and 42. The brake valves 45a and 45b are connected to the air tanks 47 and 48, respectively. Yes. In addition, air tanks 47 and 48 are directly connected to the input ports of the relay valves 35 and 36. The relay valves 35 and 36 apply pressure corresponding to the operation state of the brake pedal 45 input from the brake valves 45a and 45b. The opening degree is controlled as the signal pressure, and the pressure corresponding to the operation of the brake pedal is output. The input ports of the automatic brake pressure supply valves 37 and 38 are connected to the air tanks 47 and 48 via the air passages 43 and 44. When the valves are opened, a pressure corresponding to the internal pressure of the air links 47 and 4 is output. ing.
[0013]
Pressure sensors 51 to 54 for detecting air pressure (braking pressure) supplied to the air over hydraulic boosters 15 to 18 are connected to an air passage between the air over hydraulic boosters 15 to 18 and the pressure control valves 25 to 28. Has been. In addition, wheel speed sensors 55 and 56 are provided in the vicinity of the left and right front wheels 2L and 2R, wheel speed sensors 57 and 58 are provided in the vicinity of the left and right drive wheels 3L and 3R, and a steering angle sensor 59 is provided in the steering wheel 8. However, the brake pedal 45 is provided with a brake pedal stroke sensor 60 for detecting the depression amount of the pedal. The brake pedal stroke sensor 60 has a pedal switch function that is switched on when the brake pedal 45 is depressed.
[0014]
Further, at a predetermined position of the vehicle, a longitudinal acceleration sensor 61 that detects acceleration in the longitudinal direction of the vehicle body, a lateral acceleration sensor 62 that detects acceleration in the lateral (left and right) direction of the vehicle body, and a yaw rate that detects the rate generated in the vehicle body. A sensor 63 is provided. The detection signals of these pressure sensors 51-54, wheel speed sensors 55-58, steering angle sensor 59, brake pedal stroke sensor 60, longitudinal acceleration sensor 61, lateral acceleration sensor 62, and yaw rate sensor 63 are controlled as control means. Input to device 65. The control device 65 controls the braking force applied to each wheel by controlling the pressure control valves 25 to 28 and the automatic brake pressure supply valves 37 and 38 based on signals input from these sensors. In the present embodiment, the pressure control valves 25 to 28 and the automatic brake pressure supply valves 37 and 38 constitute safety measures.
[0015]
The operation will be described below.
First, normal brake control in which the driver depresses the brake pedal 45 to activate the main brake will be described.
When the brake pedal 45 is depressed, the brake valves 45a and 45b are opened, the braking pressure is supplied from the air tanks 47 and 48 to the relay valves 35 and 36, and the relay valves 35 and 36 are opened. When the relay valves 35 and 36 are opened, the air over hydraulic booster passes through the air passages 43 and 44, the relay valves 35 and 36, the double check valves 31 to 34, and the pressure control valves 25 to 28 from the air tanks 47 and 48. The braking pressure according to the depression amount of the brake pedal 45 is supplied to 15-18. The air over hydraulic boosters 15 to 18 generate a hydraulic pressure corresponding to the braking pressure supplied from the pressure control valves 25 to 28 to drive the wheel cylinders 5L, 5R, 6L, 7L, 6R, 7R, and the front wheels 2L. 2R, driving wheels 3L, 3R, driven wheels 4L, 4R are applied with braking force. In this way, during normal braking, braking force corresponding to the amount of depression of the brake pedal 45 is generated on all the front wheels 2L, 2R, drive wheels 3L, 3R, and driven wheels 4L, 4R.
[0016]
By the way, slipping occurs when the road surface is slippery or when the brake pedal 45 is depressed greatly during high-speed traveling and the wheel is locked by sudden braking. The control device 65 executes anti-skid control when detecting that a slip has occurred by a signal from each of the wheel speed sensors 55 to 58. At the time of anti-skid control, the slip ratio of each wheel is calculated, and the pressure control valves 25 to 28 are controlled according to the slip ratio, thereby appropriately controlling the braking force of each wheel and avoiding the lock of the wheel. .
[0017]
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 has become. When the automatic brake pressure supply valves 37 and 38 are opened, the braking pressure is applied to the pressure control valves 25 to 28 from the air tanks 47 and 48 through 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 supplied to the air over hydraulic boosters 15 to 18. The air over hydraulic boosters 15 to 18 generate a hydraulic pressure corresponding to the braking pressure supplied from the pressure control valves 25 to 28 and apply a braking force corresponding to the target braking pressure to the corresponding wheels. The braking pressure applied to the air over hydraulic boosters 15 to 18 is detected by the pressure sensors 51 to 54, respectively, and is input to the control device 65 as a feedback signal.
[0018]
Such automatic brake operation functions during yaw moment control and automatic deceleration control. The control device 65 executes yaw moment control when the deviation between the target yaw rate calculated from the steering angle and the vehicle speed and the actual yaw rate detected from the yaw rate sensor 63 is equal to or greater than a predetermined value, so that the deviation is reduced. A yaw moment generated in the vehicle is controlled by applying a braking force difference between the wheels. In addition, if the vehicle speed or lateral acceleration when the vehicle is turning is too high, the control device 65 executes automatic deceleration control that automatically decelerates the vehicle so that the vehicle speed or lateral acceleration is within a limit value.
[0019]
Further, the control device 65 activates the automatic brake even when the vehicle puncture is detected. The detection method when the vehicle tire is punctured with reference to the flowchart shown in FIG. 2 and the countermeasure at that time Will be described.
It is assumed that one wheel, for example, the left front wheel 2L burst while the vehicle is running. When the front wheel 2L bursts, the wheel speed is drastically decreased by the front wheel 2L. At this time, if the driver does not operate the steering wheel, the vehicle tilts to the front wheel 2L side despite the steering neutral state, and the yaw rate is increased. Is greatly generated, and the behavior of the vehicle 1 is disturbed. Since the yaw rate sensor 63 quickly detects a disturbance in the behavior of the vehicle and outputs a signal corresponding to the yaw rate, if such a situation is detected, a sudden vehicle puncture state such as a burst can be detected.
[0020]
FIG. 2 shows a more specific control process based on this idea. The control device 65 receives signals from the sensors and detects the wheel speed (Vw), the vehicle speed (V), the yaw rate (γ), the operating state of the brake pedal 45, and the steering angle (δH) (step S1). ), The acceleration of each wheel, that is, the left and right front wheels 2L, 2R and the left and right drive wheels 3L, 3R is calculated (step S2), and the reference yaw rate (γ ^* ) is calculated based on the vehicle speed and the steering angle (step S3). Next, the control device 65 determines whether or not the current vehicle speed (V) is equal to or higher than a predetermined vehicle speed (for example, 10 km / h) (step S4), and returns to step S1 when it is lower than the predetermined vehicle speed. By determining the vehicle speed condition in step S4, it is possible to prevent erroneous detection of vehicle driving disturbance caused by driving slip.
[0021]
The control device 65 determines whether or not the brake pedal 45 is being operated when it is determined in step S4 that the vehicle speed is equal to or higher than the predetermined vehicle speed (step S5). When the brake pedal 45 is depressed, the control device 65 proceeds to step S1. Returning, when the brake pedal 45 is not depressed, there is a wheel that satisfies the condition that the deviation between one wheel speed and the average wheel speed of the other three wheels is a predetermined value B or more (for example, the wheel of the front wheel 2L). It is determined whether or not a deviation between the speed and the average wheel speed of the front wheels 2R and the drive wheels 3L and 3R satisfies a condition that is equal to or greater than a predetermined value B (step S6). Since the tire puncture countermeasure is determined during non-braking, it is erroneously detected whether or not the vehicle behavior is disturbed due to wheel lock on a split road or the like by determining whether or not the brake pedal 45 is being operated in step S5. Disappears.
[0022]
In step S6, when 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 more than the predetermined value B is not satisfied, the process returns to step S1. There is a wheel that satisfies the condition that the deviation between the acceleration of the other wheel and the average acceleration of the other three wheels is equal to or greater than a predetermined value C (for example, 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) Whether or not the condition that the absolute value of the value is equal to or greater than the predetermined value C is satisfied (step S7). The discrimination between step S6 and step S7 is performed for each wheel. Further, the absolute value of the deviation is taken in step S6 and step S7 because it is considered that the wheel speed is fast when traveling by a wheel at the time of burst and the wheel speed is slow when the wheel is broken.
[0023]
In step S7, when 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 when the condition is satisfied, the detected yaw rate is calculated in step S3. It is determined whether or not a condition that the absolute value of the deviation from the reference yaw rate is equal to or greater than a predetermined value D (in this case, γ ^* + D corresponds to the reference value) is satisfied (step S8). When the condition is satisfied, safety measures are executed (step S9). As this safety measure, for example, the automatic braking described above is executed.
[0024]
In the above control, the determination of the vehicle speed in step S5 may be omitted. In addition, although the discrimination between step S6 and step S7 is performed for each wheel, it may be a deviation from the left and right other side (front wheels 2L and 2R, drive wheels 3L and 3R). In addition, the absolute value of the deviation is taken in the determination, but the wheel speed of one wheel (front wheel 2L, drive wheel 3L) is lower than the wheel speed of the corresponding other wheel (front wheel 2R, drive wheel 3R). It is also possible to determine only one of the side and the increase side.
[0025]
In this embodiment, as a specific method for detecting a rapid change in wheel speed, a method using the wheel speed (step S6) and a method using the wheel acceleration (step S7) are employed. Any one of the methods (determination of either step S6 or step S7) may be used.
Further, although the absolute value of the deviation between the actual yaw rate and the reference yaw rate is taken in step S8, it may be determined only when the actual yaw rate is excessive without taking the absolute value. Furthermore, the reference yaw rate (γ ^* ) may be set to a fixed value by performing the determination in step S8 only when the steering angle is in the small steering angle region. At this time, the calculation in step S3 is unnecessary.
[0026]
Further, in step S9, automatic braking is executed as a safety measure, and the engine output is suppressed by the engine control device that operates the alarm device in the cab and issues an alarm to notify the driver (for example, the fuel of the electronic governor 9). Take measures such as reducing the injection amount and suppressing engine output) to decelerate the vehicle speed, operating an outside alarm device (flashing a warning lamp, etc.), issuing an alarm and notifying other surrounding vehicles of the abnormality. Anyway.
[0027]
【The invention's effect】
As described above, according to the present invention, the deviation between the situation where the state quantity related to the wheel speed differs by more than a predetermined amount from the other wheels, the situation where the braking state is not being braked, and the reference yaw rate obtained from the steering state . Abnormal conditions such as tire bursts can be detected reliably and promptly by judging punctures in combination with situations where yaw rates occur where the absolute value is greater than or equal to a predetermined value , and safety measures are ensured under abnormal conditions Can be taken. Further, by taking safety measures only during non-braking, it is possible to prevent erroneous detection of vehicle behavior disturbance due to wheel lock on a split road or the like.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vehicle including a vehicle tire puncture countermeasure 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 coping procedure at that time.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle 2L, 2R Front wheel 3L, 3R Drive wheel 4L, 4R Driven wheel 5L, 5R, 6L, 6R, 7L, 7R Wheel cylinder 8 Steering wheel 9 Electronic governor 11-14 Braking piping (oil path)
15-18 Air over hydraulic 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 To 54 pressure sensors 55 to 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)

Wheel speed detecting means for detecting the wheel speed of each of the plurality of wheels;
Braking state determining means for determining whether or not the brake pedal is being operated;
Steering state detection means for detecting the steering state of the steering wheel;
A yaw rate detecting means for detecting a yaw rate generated in the vehicle;
Safety measures for taking safety measures on the vehicle;
When it is determined by the braking state determination means that the brake pedal is not being operated, it is detected and detected that there is a wheel whose state amount related to the wheel speed differs by a predetermined amount or more from other wheels. If the absolute value of the difference between the reference yaw rate obtained from the yaw rate and the steering state is detected to be equal to or greater than a predetermined value, the vehicle tire puncture, characterized in that a control means for actuating the safety measure means Coping device.

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