Abstract: A hydraulic circuit is provided for a by-wire brake system. There is a need for such a circuit which permits independent left and right brake operation and which has redundancy. The circuit includes left and right brake control valves, a left brake line communicated with a left brake, a right brake line communicated with a right brake, and a left-right cross-over valve operable to open and close communication between the left and right brake lines. The hydraulic circuit also includes a left shutoff valve between an outlet of the left brake valve and the left brake line, and a right shutoff valve between an outlet of the right brake valve and the right brake line.

Abstract: The invention relates to a hydraulic circuit for a steer-by-wire steering system which includes a hydraulic pump, a reservoir, a bi-directional steering actuator, a pair of electronic control units (ECU) for generating electrical steering control signals in response to an operator-generated steering command. There is a need for such a circuit which des not require large expensive valves. The hydraulic circuit includes a pair of solenoid operated directional control valve units and a pair of solenoid operated shut-off valves. Each directional control valve unit and a corresponding one of the shut-off valves are connected in series between the pump, the reservoir and the steering actuator, and are connected to a respective one of the ECUs and controlled thereby. In the absence of a fault condition both shut-off valves are open so that hydraulic flow to and from the actuator is shared by both the first and second directional control valve units.

Abstract: A vehicle brake system includes a primary hydraulic pump, a secondary variable delivery pump, left and right service brakes and left and right secondary brakes. A service brake valve is connected between the primary pump and the service brakes, and operates the service brakes in response to brake pedal operation. Left and right service brake switches generate signals representing operational status of the service brakes. An electrohydraulic secondary brake valve operates the secondary brakes in response to an electronic control signal. Brake pressure sensors generate brake pressure signals representing the service brake pressure and the secondary brake pressure. An electronic control unit is coupled to the service brake switches, to the pressure sensors and to the secondary brake valve. The control unit generates the control signal as a function of the status of the service brakes and of the brake pressure signals.

Abstract: A vehicle suspension system includes a fluid pump, a pair of suspension cylinders and a hydraulic control circuit for controlling pressurization of the suspension cylinders. Each suspension cylinder has a head end and a rod end. The control circuit includes a proportional rod pressure control valve with a first pilot which is exposed to a pressure which is communicated to the head end of the suspension cylinder, and a second pilot which is exposed to pressure which is communicated to the rod end of the suspension cylinder. The rod pressure control valve controls pressure in the rod end of the suspension cylinder as a function of and proportional to the pressure in the head end of the suspension cylinder. A suspension damping valve controls communication between a chamber of the cylinder and an accumulator.

Abstract: A vehicle brake system includes a primary hydraulic pump, a secondary variable delivery pump, left and right service brakes and left and right secondary brakes. A service brake valve is connected between the primary pump and the service brakes, and operates the service brakes in response to brake pedal operation. Left and right service brake switches generate signals representing operational status of the service brakes. An electrohydraulic secondary brake valve operates the secondary brakes in response to an electronic control signal. Brake pressure sensors generate brake pressure signals representing the service brake pressure and the secondary brake pressure. An electronic control unit is coupled to the service brake switches, to the pressure sensors and to the secondary brake valve. The control unit generates the control signal as a function of the status of the service brakes and of the brake pressure signals.

Abstract: The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere & Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere & Company or otherwise.