Nissan Motor Company Limited

Masafumi Nakayama

Tokiyoshi Yanai

Masato Fukino

Yutaka Aoyama

Moritsune Nakata

Hirotsugu Yamaguchi

Megumu Higuchi

In order to simplify the construction of a power steering system and simultaneously allow for unassisted steering in the event that the motor or the like of the system malfunctions, the differential gear which establishes the drive connection between the auxiliary motor, the steering input shaft and the steering output shaft is such that when the element of the differential gear which is connected to a variable speed motor is not driven by the motor, an essentially 1:1 drive is established between the steering input and output shafts while at this time the motor driven element is braked only by the friction and other natural resistances which occur in the system. Further, the differential gear is such as to have a relatively low responsiveness to the rotational speed of the motor and thus eliminates the need for a reduction gear between the motor and the differential gear.

Steering system for automotive vehicle or the like

This automotive vehicle power-steering system can positively compensate for resistance to the return of a steering linkage from an operating position to its neutral rest position after the vehicle turns a corner, and can enhance a steerability of the vehicle. The system includes a controller ordering a power-assist actuator to reduced the steering angular deviation of a steering wheel to zero when the controller receives a zero-level signal from a steering torque sensor and non-zero-level signal from a steering angular deviation sensor. The method for the system includes a step of controlling the power-assist actuator to generate a return-assist force counteracting the resistance and variable according to vehicle conditions.

Automotive vehicle power-steering system and method

An input shaft and an output shaft can rotate relative to each other. Pressure supplied to a pressure-responsive actuator depends on the axial position of a movable valve member. A transmission arrangement serves to move the valve member only in the axial direction as the input and output shafts rotate relative to each other. The valve member and each of the input and output shafts are wholly outside one another.

Power steering system

An inventive electrical motor-assisted power-steering system is compact while still providing adequate steering assist force. The system can also act as a manual steering system in the event of failure of an electrical motor. The system includes a steering gear with a shaft rotated manually via a steering shaft, a worm driven by the electrical motor operating in response to rotation of the steering shaft, and a worm wheel fixed to the steering gear shaft and meshing with the worm. The lead angle of the worm is selected to be larger than the friction angle between the worm and the worm wheel so that the worm wheel can drive the worm freely if the motor should fail.

Electrical motor type power-steering system

A steering apparatus, which includes a device for fluid power-assist of manual steering forces transmitted to a steering gear, a control valve controlling operation of the fluid power-assist device, a valve body of the valve being actuated in accordance with a signal indicative of steering conditions and a steering reactive-force transmitting member directly transmitting steering reactive forces to the valve body so as to displacing same in response to an abnormal steering reactive force. The steering reactive-force transmitting member corrects an abnormal position of the valve body by engaging and moving the valve body when the reactive force exceeds a predetermined magnitude.

Steering apparatus

In a vehicular power steering system, the hydraulic fluid supply to a hydraulic power actuator is controlled in accordance with the vehicle speed and the angular velocity of the steering wheel. Preferably, the fluid supply is reduced so that the steering effort becomes heavier as the vehicle speed increases while the fluid supply is increased when the angular velocity of the steering wheel is high. To control the fluid supply, there is provided, in a power steering system, a bypass valve means for draining a portion of the fluid flow to bypass the power actuator, and control means for producing a control signal to control the bypass valve means in accordance with the vehicle speed and the angular velocity of the steering wheel.

Vehicular power steering system

A control apparatus for a power-assisted steering system, comprising a power cylinder having pressure acting chambers respectively communicating with the control ports of a pressure control valve having inlet and outlet ports respectively communicable with the delivery and suction ports of a pump, and first and second flow control valves each having an inlet port and a discharge port communicating with the suction port of the pump, each flow control valve including a control pressure acting chamber communicating with a pressure acting chamber of the power cylinder to develop a differential pressure variable with a differential pressure between the pressure acting chambers of the cylinder, and a valve member movable in response to the differential pressure acting thereon and urged to provide communication between the inlet and discharge ports of each flow control valve, the inlet port of the first flow control valve being in constant communication with the delivery port of the pump and the inlet port of the pressure control valve, the inlet port of the second flow control valve being in constant communication with the outlet port of the pressure control valve, the valve member of each flow control valve being operative to block the communication between the inlet and discharge ports of the valve when the differential pressure is higher than a predetermined value, the second flow control valve further comprising a bypass providing constant communication between the outlet port of the pressure control valve and the suction port of the pump independently of the valve member.

Control apparatus for vehicle steering system

A control apparatus for a power-assisted vehicle steering system, comprising a power cylinder having two pressure-acting chambers, a control valve having inlet and outlet ports respectively communicable with a pump and a fluid reservoir and selectively with the inlet and outlet ports, a pressure compensating valve having an inlet port communicating with the pressure-acting chambers, outlet and control ports and a valve member for varying the degree of communication between the inlet and outlet ports, the fluid pressure in the inlet port being variable with the fluid pressure from the pump and urging the valve member to move in one direction and a spring urging the valve member to move in the other direction to maintain constant the differential pressure between the inlet and outlet ports, and a pressure reducing valve having an inlet port communicating with the outlet port of the compensating valve, a discharge port communicating with the reservoir and the control port of the compensating valve and a valve member to vary the degree of communication between the inlet and discharge ports of the reducing valve, the fluid pressure in the discharge port being directed to the control port and developing therein the fluid pressure urging the valve member of the compensating valve for movement in the said other direction, the valve member of the reducing valve being responsive to a signal variable with vehicle speed.

Fluid-operated control apparatus for power-assisted steering system of

In a venturi type fuel supply apparatus wherein a resistance member biased by a spring against a negative suction pressure is provided in an air suction passage to engage a throat formed therein and a needle valve is moved by the resistance member, a unitary structure for metering and ejecting fuel is disposed at the center of the air suction passage. The unitary structure comprises an outer and inner nozzles defining therebetween an air-fuel passage leading to fuel ejection ports. The lower end of the needle valve extends through the inner nozzle which communicates with a source of fuel.

Growing community of inventors

Yamato, Japan

Masafumi Nakayama