Sumitomo Rubber Industries Limited

Sumitomo Electric Industries, Limited

Other

Sumitomo Electric, Ltd.

Sumitomo Rubber Ind.

Mikao Nakajima

Isao Isshiki

Hiroto Horie

Minao Yanase

Yasushi Kobayashi

Toshihiro Toda

Akiko Iida

Masaaki Komazawa

A tire air-pressure abnormality alarming device for informing decrease in air-pressure of tires attached to a four-wheeled vehicle, characterized in that the device prohibits start of initializing operations for updating stored values for physical amounts related to tires or wheels in the case where air-pressures of the tires are judged to be normal, if air-pressure abnormality of a tire is being alarmed. Initialization is accepted only after the internal pressure has become normal, whereby erroneous initialization with any tire being in a decompressed condition can be prevented. Thus, normal operations for detecting decompression of a tire can be maintained.

Tire air-pressure abnormality alarming device and method thereof

Initial correction factor determining device and device utilizing the

A device for finding correction factors for correcting outputs of rotational velocity detectors used for detecting the rotational velocities of four tires mounted on a vehicle. The device judges whether or not the vehicle is traveling linearly. If the vehicle is traveling linearly, an initial correction factor K.sub.1 for eliminating the effect of a difference in effective rolling radius between the right and left front tires, and an initial correction factor K.sub.2 for eliminating the effect of a difference in effective rolling radius between the right and left rear tires, are calculated on the basis of the outputs of the rotational velocity detectors. When it is judged that the vehicle is coasting linearly, an initial correction factor K.sub.3 for eliminating the effect of a difference in effective rolling radius between the front tire and the rear tire is calculated.

Device for determining initial correction factor for correcting

A tire pressure drop detecting method, capable of accurately detecting whether the pneumatic pressure of a tire has dropped even if a large driving torque is exerted on the tires. The rotational angular velocities of tires provided for a vehicle are detected and a front/rear acceleration of the vehicle is detected, and then it is discriminated whether the vehicle is in a predetermined decelerated state or not, based on the detected front/rear acceleration of the vehicle. If the vehicle is in the predetermined decelerated state, it is judged whether the pneumatic pressure of the tires has dropped, based on the detected rotational angular velocities. The pneumatic pressure drop of the tire is judged only when the vehicle is in the decelerated state where a difference between the rotational angular velocity of the tire at the time of pneumatic pressure drop and that at the time of a normal inner pressure is relatively large.

Method of and device for detecting tire pressure drop

A tire pressure drop detecting method, which executes a pneumatic pressure drop judging processing for autocruise traveling when the vehicle is in a state of autocruise traveling. It is judged based on a front/rear acceleration of the vehicle whether the vehicle is in a state of autocruise traveling or not. Furthermore, the pneumatic pressure drop judging processing for autocruise traveling is performed by using a judging threshold value which is set to become smaller as the speed of the vehicle becomes larger.

A method of and a device for determining a turning radius of a vehicle, accurately, without being influenced by the load movement of the vehicle, are disclosed. The rotational angular velocities of left and right tires are detected, respectively. The turning radius of the vehicle is determined, based on the detected rotational angular velocity, by taking a change in effective rolling radiuses due to the load movement of the vehicle into consideration.

Method and device for calculating turning radius of vehicle taking load

A method of and a device for detecting a pneumatic pressure drop of tires provided for a vehicle are disclosed. Rotational angular velocities of tires are determined and a judged value D is determined based on the determined rotational angular velocities. A speed of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius R of the vehicle are substituted into a predetermined polynominal expression which is defined so that an influence of the turning radius R is exerted on all terms to determine a correction value. A judged value D' after correction is determined by correcting the judged value D using the correction value. It is judged whether a tire pressure drops or not, based on the judged value D' after correction. In such way, a tire pressure drop can be detected, accurately, excluding an influence of the turning radius R of the vehicle.

Method of and device for detecting tire pressure drop based on angular

A tire pressure drop alarm device for judging a pneumatic pressure drop by calculating rotational angular velocities of tires provided for a four-wheel vehicle. When the vehicle is traveling on a road which varies in condition between left and right sides, a front/rear ratio of rotational angular velocities of the tires at the shoulder side of the road changes more markedly than that of rotational angular velocities of the tires at the center side, and a large time differential value appears. Therefore, it is possible to judge the traveling condition of the vehicle when the road condition varies between left and right sides. When it is judged that the traveling condition of the vehicle encounters a road condition which varies between left and right sides, the tire rotation of the four wheels is likely to become unbalanced, giving a false alarm even if the tire pressure does not drop. In this case, the judgment by the pneumatic pressure drop judging means is inhibited to prevent an issuance of a false alarm.

Tire pressure drop alarm device sensing partial travel on irregular road

According to the tire air-pressure reduction detecting apparatus and method of the present invention, when a vehicle travels, the detected rotational angular speeds F.sub.i of the tires W.sub.i are multiplied by correction coefficients C.sub.i to correct initial differences. Vehicle speed V.sub.0 is calculated based on angular speeds F.sub.i0, and is put in a relationship formula f(V) to obtain a front/rear wheel ration f(V.sub.0) corresponding to the speed V.sub.0. Based on the front/rear wheel ratio f(V.sub.1) corresponding to a speed V.sub.1 at which the correction coefficients C.sub.i have been obtained, and the ration f(V.sub.0), there is obtained a variation of the front/rear wheel ratio f(V.sub.0)/f(V.sub.1), by which rotational angular speeds F.sub.3, F.sub.4 are then multiplied. The products are used for detecting a reduction in the air pressure of a tire W.sub.i, thereby to calculate a judgement value D. When D satisfies the conditions:

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Osaka, Japan

Mikao Nakajima