JP3129555B2 - Tire pressure abnormality detection method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting abnormal tire air pressure in vehicles such as passenger cars and trucks. More specifically, while realizing low cost by using ABS (anti-lock-braking-system) wheel speed pulses, the minimum cost increase of one acceleration detector and the simultaneous increase of two or more wheels are achieved. The present invention relates to a method and an apparatus that can easily and reliably detect an abnormality.

[0002]

2. Description of the Related Art The pressure of a tire greatly affects the performance of a vehicle, and the reduction of the pressure is a problem related to safety. For this reason, many means for detecting an abnormal air pressure of a tire have been conventionally proposed. However, these proposals did not spread widely because it was difficult to achieve both high reliability and low cost in practical use. In recent years, with the spread of ABS, a system that uses the wheel speed pulse of the ABS and has both low cost and high reliability has been proposed. He is worried about simultaneous abnormalities over the ring.

[0003]

By the way, devices for detecting such air pressure abnormalities are generally classified into several types by means of detection. One is a type that directly detects the air pressure, and the other is a type that detects a physical quantity (a deflection amount, a rotation speed, and the like) that changes according to the air pressure.

[0004] The former is advantageous in reliability, but has a difficult problem such as transmission of a signal from the rotating body to the fixed side, so that the apparatus is complicated and tends to be expensive. In the latter, the device is simple and inexpensive, but has poor reliability.

In a system for detecting an abnormal air pressure based on the wheel speed, the abnormality is usually determined by comparing the wheel pressure with a wheel speed pulse of a normal wheel. Therefore, the air pressure of at least one tire must be normal. The simultaneous abnormality of four wheels cannot be detected theoretically.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a method and apparatus for detecting an abnormality in tire pressure, which is low-cost, highly reliable, and capable of detecting abnormalities of four wheels at the same time. I do.

[0007]

According to the present invention, (a) 4
Detecting the angular velocity of each wheel of a wheeled vehicle equipped with a tire; (b) generating a signal proportional to the detected angular velocity; (c) detecting the longitudinal acceleration of the vehicle; (d) detecting Integrating the determined acceleration to determine a vehicle speed; (e) generating a signal proportional to the determined vehicle speed; and (f) generating a signal proportional to the angular speed and the vehicle speed. A step of calculating a proportional signal, wherein the step of calculating the signal is performed at a speed determined at a normal air pressure.
And then calculate the angular speed of each wheel for each speed.
A table created in advance by Rukoto, tire pressure is normal, the relationship between the vehicle running speed and the wheel angular velocity from shown to tables, wheels in the table in the running speed in actual running of, determine the angular velocity at the normal air pressure, and the angular velocity and a wheel in real running at normal air pressure velocity and compared for each wheel, 0.05% with respect to the wheel of the angular velocity of the difference is the table If it is 0.60%, it is a step to activate the device that warns of abnormality of the tire ,
Provided is a method for detecting an abnormality in tire pressure of a vehicle, capable of detecting simultaneous decompression of two or more wheels .

Further, according to the present invention, an angular velocity detecting means for detecting an angular velocity of each wheel on which a tire is mounted in a four-wheel vehicle,
Angular velocity signal generating means for generating a signal proportional to the detected angular velocity, acceleration detecting means for detecting longitudinal acceleration of the vehicle, integrating means for integrating the detected acceleration to obtain the running speed of the vehicle, Speed signal generating means for generating a signal proportional to the traveling speed; and arithmetic processing means for arithmetically processing the signals emitted from the angular velocity signal generating means and the speed signal generating means, wherein the arithmetic processing means is determined by normal air pressure. At a given speed
Work by calculating the angular velocity of each wheel for each speed.
A made table, tire pressure is normal, the relationship between the vehicle running speed and the wheel angular velocity from shown to Te over <br/> table, in the table in the running speed in actual running of the wheels, determine the angular velocity of the normal air pressure, this normal
The angular velocity at the air pressure and the angular velocity of the actual running wheel
To be compared each, the difference is the step of activating the abnormality warning device of the tire if 0.60% to 0.05% with respect to the angular velocity of the wheels of the table, co-down of more than two wheels
An apparatus for detecting an abnormality in tire pressure of a vehicle , the pressure being detectable, is provided.

[0009]

In the present invention, the current running speed of the vehicle is obtained by measuring the acceleration of the vehicle by a sensor and integrating the measured acceleration from the time when the vehicle stops.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for detecting an abnormality in the tire pressure of a vehicle (hereinafter, simply referred to as a detection method) according to the present invention will be described for each process.

In the step (a), each wheel-mounted tire of a four-wheeled vehicle is detected from wheel speed pulses emitted from the ABS by using an angular speed detecting means such as a pulse counter.
The angular velocity of the wheel is detected. Then, in step (b), a signal proportional to the angular velocity is generated by using an angular velocity signal generating means such as a D / A converter, so that the vehicle that is actually traveling
The angular velocity of each wheel of the vehicle is constantly monitored.

In the step (c), an acceleration sensor such as a piezoelectric or strain gauge type acceleration transducer is used.
By monitoring a voltage proportional to the acceleration, the longitudinal acceleration of the vehicle can be determined. This acceleration is sent to an A / D converter via a filter to be converted into a digital signal, and is sampled at regular time intervals.

In the step (d), the acceleration of the sampled digital value is integrated from the stop of the vehicle by using an integrating means such as an integrating circuit, and the actual traveling is performed.
Find the running speed of the middle vehicle. The integration is performed using, for example, the trapezoidal rule. In the step (e), a signal proportional to the running speed is generated by using a speed signal generating means such as a D / A converter to constantly monitor the running speed of the vehicle.

In the step (f), the wheels at normal air pressure at the running speed of the vehicle determined in the step (d)
Of previously obtained from created table angular velocity, comparing this with the step of the wheel obtained in (a) the angular velocity. At this time, the signals emitted in steps (e) and (b) are used. And the difference between the two angular velocities is the wheel of the table
If the angular velocity is between 0.05% and 0.60% of the angular velocity, a device that warns of an abnormality is activated. The warning can be given by using an auditory object such as a buzzer or a visual object such as a lamp.

In the step (f), a table describing the angular velocity of the wheel at the normal air pressure of each tire at each speed is required. Such a table is used for the actual traveling straight ahead at every speed determined by the normal air pressure. It can be created by calculating the angular velocity of the wheel for each speed. Table 1 shows an example of such a table.

[0016]

[Table 1]

[0017] Since the angular speed of the wheel varies with the traveling speed of the vehicle, so as to hold the to previously obtain the angular velocity of the wheels at any speed for every tire in a state of normal pressure, this in table .

Further, since the angular velocity of the wheel changes due to load, turning, abrasion and braking / driving in addition to the air pressure and speed, means for removing these effects, for example, whether the vehicle is turning or not can be determined. For determining whether or not braking / driving is being performed (see Japanese Patent Application Laid-Open No. 63-305011)
By using together, accuracy can be further improved.

[0019]

The detection method according to the present invention utilizes the wheel pulse of the ABS, so that the reliability of the system can be improved and the cost can be reduced. In addition, since the vehicle speed is obtained by integrating the acceleration measured by the acceleration sensor, and based on the obtained vehicle speed, the tire pressure reduction is determined.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-271907 (JP, A) JP-A-63-305011 (JP, A) European Patent Application Publication 291217 (EP, A1) French Patent Application Publication 2568519 (FR, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60C 23/00-23/08 G01L 17/00

Claims (2)

(57) [Claims] (A) detecting the angular velocity of each wheel equipped with tires of a four-wheeled vehicle; (b) generating a signal proportional to the detected angular velocity; (c) longitudinal acceleration of the vehicle. (D) integrating the detected acceleration to determine a vehicle speed, (e) generating a signal proportional to the determined vehicle speed, and (f) determining the angular velocity. Calculating a proportional signal and a signal proportional to the traveling speed of the vehicle, wherein the step of calculating the signal is determined at normal air pressure.
The vehicle travels straight ahead at each speed, and the angular speed of each wheel at each speed.
A table created in advance by determining the degree
Te, tire pressure is normal, the relationship between the vehicle running speed and the wheel angular velocity from shown to tables, the wheels in the table in the running speed in actual running, the normal air pressure Contact
Seeking kicking angular speed, long the normal and the angular velocity at the air pressure and the wheel angular velocity in the actual running to compare for each wheel, 0.60 percent 0.05% relative to the wheel of the angular velocity of the difference is the table For example, a method of operating a device for warning an abnormality of the tire, wherein the simultaneous decompression of two or more wheels can be detected . 2. An angular velocity detecting means for detecting an angular velocity of each wheel equipped with tires of a four-wheeled vehicle, an angular velocity signal generating means for generating a signal proportional to the detected angular velocity, and an acceleration for detecting a longitudinal acceleration of the vehicle. Detecting means, integrating means for integrating the detected acceleration to determine the running speed of the vehicle, speed signal generating means for generating a signal proportional to the determined running speed of the vehicle, and said angular speed signal generating means and speed signal generating means And arithmetic processing means for arithmetically processing the signal emitted from the control unit, wherein the arithmetic processing means is provided for each speed determined at normal air pressure.
Performs a straight real run, determine the angular velocity of each wheel in each velocity
A table created in advance by the air pressure in the tire is normal, the relationship between the vehicle running speed and the wheel angular velocity from shown to tables, in the table in the running speed in actual running, normal determine the angular velocity in air pressure,
The angular velocity at this normal air pressure and the angular velocity of the wheels during actual running are
The then compared for each wheel, if 0.60 percent 0.05% relative to the wheel of the angular velocity of the difference is the table actuates the device to warn the abnormality of the tire, 2 or more wheels simultaneous deflation
An apparatus for detecting an abnormality in tire pressure of a vehicle, wherein the apparatus is capable of detecting a tire pressure.