Nissan Motor Company Limited

Kenro Takahashi

Naohiko Inoue

Masahiro Tsukamoto

Jun Watanabe

Naoto Fukushima

Yukio Fukunaga

Yohsuke Akatsu

Itaru Fujimura

Shigeru Kamegaya

Kensuke Fukuyama

Masaharu Satoh

Tadashi Yamashita

Yorihito Nakao

A torque is transmitted between a fluid pressure pump driven together with drive of a vehicle, and a fluid pressure motor that rotates together with driven wheels. The fluid pressure motor has two ports, and rotates in accordance with the direction of fluid supply to the ports. Fluid is circulated from one port to the other according to the input of rotation torque from the driven wheels. A high pressure flowpath connected to the pump outlet, and a low pressure flowpath connected to the pump inlet, are connected to these ports, and the connection direction is reversed when the rotation direction of the drive wheels is reversed. The low pressure flowpath is therefore always at low pressure regardless of the rotation direction of the drive wheels, and by controlling the pump supply flowrate so as not to exceed a predetermined value, torque is not transmitted when the vehicle is running at high speed.

Four wheel drive mechanism

A working fluid circuit for an active suspension control system for an automotive vehicle comprises a pressure source unit which provides pressurized working fluid to actuators, associated with wheels respectively, which are operable to suppress attitude change of a vehicle body, pressure control valves associated with the actuators respectively, and check valves located in a by-pass from an output port to a supply port of the pressure control valve, the supply port communicating with the pressure source through a supply line to which the working fluid is supplied from the pressure source, the output port communicating with the actuator through an output line for outputting the working fluid adjusted at a preselected controlled level to the actuator. Each of the check valves is responsive to pressure of the working fluid in the output line which is greater than that in the supply line for feeding back the working fluid in the output line to the supply line for providing a part of pressure supplied to said pressure control valve.

Working fluid circuit for active suspension control system of vehicle

A pressure control valve for adjusting a controlled pressure supplied to an actuator includes first and second valves. The first valve serves to modify a pressure level of a working fluid supplied from a fluid pressure source to a preselected level and provides it to the actuator. The second valve is responsive to a control signal commanding elevation or reduction in the controlled pressure from a controller to adjust a supply pressure level from the fluid pressure source to provide a pilot pressure, elevated or reduced to a preselected level, to the first valve for activating same. When elevating or reducing the pilot pressure, the second valve decreases the supply pressure level from the fluid pressure source by a preselected degree, for balancing a flow gain when elevating the pilot pressure with that when reducing the pilot pressure, for providing uniform response for elevation and reduction of the controlled pressure to the actuator.

Pressure control valve for active suspension control system

An actively controlled automotive suspension system comprises a hydraulic cylinder disposed between a vehicle body and a suspension member pivotably mounted on the vehicle body, a pressurized fluid source connected to the hydraulic cylinder, a pressure accumulator connected to the hydraulic cylinder for absorbing pressure fluctuation in the hydraulic cylinder, a variable throttling orifice, interposed between the hydraulic cylinder and the accumulator, for variably restricting fluid flow, a pressure control valve for adjusting fluid pressure in the hydraulic cylinder, sensors for monitoring state of a vehicular attitude change, and a controller associated with both of the pressure control valve and the variable throttling orifice for controlling magnitude of fluid pressure in the hydraulic and a throttling ratio of the throttling orifice.

Actively controlled suspension system for automotive vehicles

An active suspension system is provided a timing control valve in a supply line. The timing control valve is so designed as to provide a predetermined magnitude of delay in building up line pressure upon initiation of suspension control operation. A flow restriction means is further provided in parallel relationship to the timing control valve for permitting fluid flow therethrough in limited flow rate so that sudden increasing of the line pressure in the supply line can be successfully prevented.

Working fluid circuit for automotive active suspension system with

An active suspension system includes a hydraulic circuit associated with a pressure control valve for adjusting fluid pressure in a working chamber of an active cylinder. A variable orifice is provided between a control portion of the pressure control valve and the working chamber. The variable orifice is operated to provide a first full path area while a line pressure in a supply line for feeding pressurized fluid to said pressure control valve is higher than a predetermined pressure level and a second restricted path area when the line pressure is lower that the predetermined level.

Active suspension system with hydraulic circuit having line pressure

A pressure control valve unit to be employed in an active suspension system includes a valve member movable between a pressure increasing mode position, a pressure decreasing mode position and a pressure holding mode position for adjusting fluid pressure in a working chamber of an active cylinder disposed between a vehicular body and a suspension member rotatably supporting a road wheel. The valve member is further movable to a pressure relieving position in response to a pressure in the working chamber higher than a predetermined value. The valve member at the pressure relieving position establishes fluid communication between the working chamber and a drain line for draining pressurized fluid in the working chamber at a draining rate higher than that in said pressure decreasing mode position.

Active suspension system and pressure control valve therefor

A proportioning valve assembly has a supply port through which a pressurized working fluid is supplied, a drain port through which a pressurized working fluid is drained, and a control port connected to a working chamber defined in a hydraulic cylinder disposed between a vehicular body and a suspension member rotatably supporting a vehicular wheel. The proportioning valve assembly further includes a valve member for adjusting working fluid pressure to be supplied to the working chamber via the control port. A flow restricting orifice is provided in the proportioning valve assembly. The flow restricting orifice employed is designed to provide variable flow restriction depending upon working fluid condition and/or the direction for achieving stabilization of pilot pressure or road shock absorption.

Proportioning valve assembly and actively controlled suspension system

A hydraulic circuit for an active suspension system employs a pressure accumulator connected to a drain line at an orientation upstream of a pilot operated operational one-way check valve. The pressure accumulator absorbs back pressure generated in the drain line due to flow resistance in the drain line.

Active suspension system with enhanced response characteristics

A proportioning valve assembly employs an electromagnetic acuator, such as a proportioning solenoid, associated with a driver circuit. The driver circuit is provided a lead phase circuit for providing a lead phase in supplying a supply current for controlling the valve position of the proportioning valve. Providing appropriate lead time reduces necessity of high gain in attitude change suppression mode operation. Therefore, the response characteristics in pressure adjustment in the shock absorbing mode operation, can be prevented from falling an excessive level.

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Kanagawa, Japan

Kenro Takahashi