Vehicle antiskid control system

Claim 2

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of the wheel velocity voltage signal in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser to which the wheel velocity signal is applied through said switching means when said switching means is conductive and means for allowing the condenser to discharge when the wheel velocity signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the wheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noisefree response to wheel velocity for controlling said brake pressure modulation.

Claim 3

An antiskid control system according to claim 1, in which the comparison circuit compares the memorized minimum value which is the terminal voltage of said condenser in said holding circuit and a signal of voltage which is obtained by reducing the wheel velocity signal voltage at a preset rate, the voltage reduced at the present rate corresponding to a voltage at the interconnection of a pair of resistances in series with each other between the ground and the output side of said means for converting the wheel velocity into voltage signals; and a deceleration detection switch being arranged on the vehicle body to operate when the deceleration of the vehicle body reaches a preset value in such a manner that, with said switch in a conductive condition, another resistance is added to said pair of resistances to alter said preset rate at which the wheel velocity signal voltage is to be reduced, the brake reducing action of said brake pressure modulator being arranged to be stopped by the output of said comparison circuit according to the coefficient of friction of the road surface.

Claim 4

An antiskid control system according to claim 1, in which the comparison circuit compares the memorized minimum value which is the terminal voltage of said condenser in said holding circuit and a signal of voltage which differs from the wheel velocity signal voltage by a preset value of voltage; and said preset voltage difference corresponds to a potential difference between the two ends of a resistance through which there flows a collector current of a transistor which is arranged with a collector terminal connected to the output side of said means of converting the vehicle velocity into voltage signals and with a base current of a preset value being applied to said transistor, and the brake pressure reducing action of said brake pressure modulator being arranged to be stopped by the output of the comparison circuit.

Claim 5

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of the wheel velocity voltage in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser having a terminal connected to a power source through the switching means when the switching means is conductive, a transistor having its output terminals connected across the condenser and having its control terminals coupl-d to the wheel velocity voltage signal, said transistor allowing the condenser to discharge when the wheel velocity voltage signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the sheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noise-free response to wheel velocity for controlling said brake pressure modulator.

Claim 6

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of the wheel velocity voltage in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser having a terminal connected to a power source through the switching means when the switching means is conductive, a transistor having its output terminals connected across the condenser and having its control terminals coupl-d to the wheel velocity voltage signal, said transistor allowing the condenser to discharge when the wheel velocity voltage signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the sheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noise-free response to wheel velocity for controlling said brake pressure modulator.

Claim 7

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of wheel velocity voltage signal in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser to which the wheel velocity signal is applied through said switching means when said switching means is conductive and means for allowing the condenser to discharge when the wheel velocity signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the wheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noisefree response to wheel velocity for controlling said brake pressure modulation, wherein the other input of said comparison circuit is a wheel velocity voltage signal which is reduced at a given rate, wherein the wheel velocity voltage signal is the voltage provided by a resistive voltage divider connected to said wheel velocity voltage signal and wherein a deceleration detector switch which operates when the vehicle deceleration reaches a given value is provided on the vehicle structure in such a way as to add another resistance to said resistive divider to make the reducing rate of the wheel velocity voltage signal variable when the switch is in an energized condition, so that the brake pressure reducing operation of said brake pressure modulator can be stopped according with the coefficient of friction of the road surface.

Claim 8

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of wheel velocity voltage signal in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser to which the wheel velocity signal is applied through said switching means when said switching means is conductive and means for allowing the condenser to discharge when the wheel velocity signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the wheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noisefree response to wheel velocity for controlling said brake pressure modulation, wherein the other input of said comparison circuit is a wheel velocity voltage signal which is reduced at a given rate, wherein the wheel velocity voltage signal is the voltage provided by a resistive voltage divider connected to said wheel velocity voltage signal and wherein a deceleration detector switch which operates when the vehicle deceleration reaches a given value is provided on the vehicle structure in such a way as to add another resistance to said resistive divider to make the reducing rate of the wheel velocity voltage signal variable when the switch is in an energized condition, so that the brake pressure reducing operation of said brake pressure modulator can be stopped according with the coefficient of friction of the road surface.

Claim 9

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of the wheel velocity voltage signal in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser to which the wheel velocity signal is applied through said switching means when said switching means is conductive and means for allowing the condenser to discharge when the wheel velocity signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the wheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noisefree response to wheel velocity for controlling said brake pressure modulation, wherein the other input to said comparison circuit is a voltage signal differing in voltage from the wheel velocity voltage signal by a given value of voltage; and the given value of voltage difference corresponds to a potential difference between both ends of a resistor through which the collector current of a transistor flows, said transistor being arranged to have the collector terminal thereof connected to the output side of said means of converting wheel velocity into a voltage signal, while a given value of a base current is applied to said transistor.

Claim 10

An antiskid control system for vehicles comprising: means for converting wheel velocity into voltage signals; means for detecting the commencement of a wheel locking state and for providing a control signal upon the detection of said locked state; a brake pressure modulator for reducing brake pressure in response to said control signal; a low peak value holding circuit for memorizing a minimum value of the wheel velocity voltage signal in a wheel velocity control cycle, said circuit including switching means which is normally conductive and which becomes non-conductive after said control signal appears, a condenser to which the wheel velocity signal is applied through said switching means when said switching means is conductive and means for allowing the condenser to discharge when the wheel velocity signal falls during a non-conductive condition of said switching means and for preventing condenser discharge when the wheel velocity signal reaches a minimum value; and a comparison circuit for comparing the wheel velocity voltage signal and the memorized minimum value in said holding circuit, said memorized minimum value being the voltage across said condenser, said comparison circuit providing an output signal to stop the brake pressure reducing action of said modulator, said system thereby providing a substantially noisefree response to wheel velocity for controlling said brake pressure modulation, wherein the other input to said comparison circuit is a voltage signal differing in voltage from the wheel velocity voltage signal by a given value of voltage; and the given value of voltage difference corresponds to a potential difference between both ends of a resistor through which the collector current of a transistor flows, said transistor being arranged to have the collector terminal thereof connected to the output side of said means of converting wheel velocity into a voltage signal, while a given value of a base current is applied to said transistor.