Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Nippondenso Kabushiki Kaisha

Koichi Toyama

Atutoshi Okamoto

Hiroshi Arai

Akio Sugiura

Akira Nakamura

Takahiro Nogami

Koichi Taniguchi

Yoshiaki Nakano

An improved anti-skid system for a vehicle which effectively utilizes an approximated slip ratio between vehicle or body velocity and wheel velocity to generate a brake release signal for a brake release valve but without actually utilizing a vehicle or body velocity detector. Storage apparatus is used to store a reference signal representing vehicle velocity but actually corresponding to a present or just past maximum value of wheel velocity. Control apparatus is then utilized for removing energy from the storage apparatus at a controlled predetermined rate chosen to approximate the expected vehicle deceleration (but without using an actual vehicle or body deceleration detector) such that the reference signal (capacitor voltage) will continue to accurately represent approximate vehicle velocities even during periods of deceleration. Various exemplary embodiments are described for the control apparatus which may be used to hold the discharge rate constant, to change it from a first low rate to a second high rate during brake release (for compensating inherent time lags in the vehicle brake system) and/or to continuously change the rate in an inverse dependency upon wheel deceleration to even more closely approximate actual vehicle deceleration under variable road conditions. Other features of the improved system may be used to result in rapid oscillatory brake releases as a transition both before and after a more prolonged brake release period to provide for smoother operation of the anti-skid system. Spurious influences of any A.C. ripple components on the detected wheel velocity signal may also be substantially eliminated by using some of the features of this system.

Anti-skid system for a vehicle

An antiskid control device for vehicles, comprising a timer circuit for producing a timing signal in synchronism with the extinction of a release signal for a skid control, apparatus for rapidly increasing the braking pressure applied to the wheel in response to said timing signal coming from the timer circuit, and correcting apparatus for increasing the braking pressure increasing rate when a large amount of friction is present between the wheel and the road surface, said antiskid control device being able to hold the fluctuation of the braking pressure within a narrow range to prevent unnecessary vibrations of the vehicle at the time of braking due to the fact that the braking pressure increasing rate is changed when the braking pressure is reapplied to the wheel, and being able to control the braking operation at all times in a manner best suited to the various road surface conditions encountered so that a skid of the vehicle is prevented from occurring and the braking distance is reduced greatly, due to the fact that the braking pressure increasing rate is adjusted in accordance with the coefficients of friction between the wheel and the road surface.

Antiskid control device for vehicles

An anti-skid control system for preventing skidding of a vehicle caused by the braking of the vehicle while it is in motion in the system when a vehicle speed signal generated from vehicle speed detecting apparatus becomes lower than a predetermined value, discriminating apparatus generates a discrimination signal and the braking pressure applied to the wheel is modulated through limiting apparatus including a logical gate and controlled by the discrimination signal. On the other hand, when the vehicle body speed becomes lower than a predetermined value, the generation of the discrimination signal is prevented by a deceleration sensor, thus suitably controlling the braking pressure in accordance with the surface conditions of the road.

Anti-skid control system for vehicles

Growing community of inventors

Kariya, Japan

Koichi Toyama