Hydraulic Power Assist Definition Full Time Part Time Power Steering Hydro-mechanical Power Steering (HMPS) Hydro-mechanical Power Steering

Hydraulic Power Assist Definition Full Time Part Time Power Steering Hydro-mechanical Power Steering (HMPS) Hydro-mechanical Power Steering www.phwiki.com

Hydraulic Power Assist Definition Full Time Part Time Power Steering Hydro-mechanical Power Steering (HMPS) Hydro-mechanical Power Steering

Sagon, Erica, Fashion Reporter & Editor of “Yes” has reference to this Academic Journal, PHwiki organized this Journal Hydraulic Power Assist Definition Hydraulic power assist means that a hydraulic system is incorporated with mechanical steering Full Time Part Time Power Steering Part Time The as long as ce of the center springs of the valve gives the driver the “feel” of the road at the steering wheel. Full Time The valve is installed without centering springs. Any movement of the steering wheel results in hydraulic boost being applied. (Vickers, 1967)

Alfred Adler Graduate School US www.phwiki.com

This Particular University is Related to this Particular Journal

Hydro-mechanical Power Steering (HMPS) Hydro-mechanical power steering was the first type to be used on agricultural tractors in the early 1950’s. Suitable as long as small to medium tractors where power steering can be an option to manual steering. Once the size of the tractor becomes too big as long as manual steering, hydro-mechanical steering is usually not cost effective. (Wittren, 1975) Hydro-mechanical Power Steering There are many different types of hydro-mechanical power steering, but they all can be grouped into four basic groups. Steering linkage mounted integral valve in addition to actuator Steering wheel mounted control valve, linkage mounted actuator Separate control valve in addition to actuator mounted in best position Integral valve in addition to actuator mounted at steering wheel HMPS Type 1 Easiest to adapt to an existing mechanical steering layout. Only two hoses are needed. The integral valve in addition to actuator coupled to steering linkage. (Wittren, 1975)

HMPS Type 2 Creates a highly congested area with all of the hoses. Four Hoses are needed: supply, return in addition to a pair to the actuator. Creates noise, heat in addition to vibration (Wittren, 1975) Steering column mounted control valve with separate, remote actuator coupled to a linkage member. HMPS Type 3 Keeps the area around the steering wheel from becoming too congested. Four hoses are required. (Wittren, 1975) Control Valve in addition to actuator separately mounted in the steering linkage. HMPS Type 4 Most sophisticated design Requires little or no steering linkage modification. Requires larger space envelope than other types. (Wittren, 1975) The control valve in addition to the actuator are mounted on the steering column, the actuator drives the pitman arm by rack in addition to pinion or by crank arm means.

Integral Linkage Power System-hydraulic assist Pitman arm operates steering gear through drag link (B) Power cylinder thrust at steering arm (C) Boosters actuate left wheel steering arm, right wheel steered by cross steering arm (D) Only lines to booster are pressure in addition to tank Frame absorbs shock instead of steering gear, easy to service (Vickers, 1967) Remote Linkage System Steering valve is remote mounted, not with cylinder This linkage system allows as long as mechanical steering (Vickers, 1967) Combined Integral Remote System Two cylinders One cylinder has integral linkage Second cylinder is operated by the same valve The steering valve has an extra set of ports as long as the connection (Vickers, 1967)

Remote Dual System Two cylinders operated by single valve Valve connects pitman arm in addition to left cylinder Common on rear wheel steer (Vickers, 1967) Power Steering Circuits General Circuit Integral Steering Unit Circuit Remote Linkage System Circuit (Vickers, 1967) General Circuit Components Manual Steering Gear Power Steering Pump Power Cylinder Valves Relief Flow Control Steering Filters Oil Air Breather Oil Reservoir Hydraulic Lines (Vickers, 1967)

General Circuit Manual Steering Gear Transmits motion of the steering wheel to the turning of the wheel. Could be eliminated, but there are two reasons as long as not doing so. Hydraulic system failure. The public is not ready as long as a 1 to 1 ratio steering system. (Vickers, 1967) General Circuit Power Steering Pump Usually a vane-type pump or similar. Driven by the engine. Power Cylinder Double-acting differential cylinder. Steering response to left in addition to right turns is slightly different. Hardly noticeable. (Vickers, 1967) General Circuit Valves Relief Valve Required to protect the pump. Flow Control Valve Helps maintain a constant flow. Variations in engine speed would affect pump flow without flow control valve. Steering Valve A four way valve that functions as a positioning servo valve. Most are open-center. (Vickers, 1967)

General Circuit Filters Oil Filter Preferably installed in the return line. A 10-micron or smaller filter is recommended. Air Breather Filter The “breather” or vent in the reservoir. A 3-micron filter is recommended. (Vickers, 1967) General Circuit Oil Reservoir Must be large enough to hold more than all of the oil as long as the system. Should be capable of dissipating heat in oil. Hydraulic Lines Flexible hoses due to the steering components movements. (Vickers, 1967) Special Power Steering Circuits Integral Steering Unit Circuit A simple circuit with the valve in addition to cylinder mounted together. Remote Linkage System Circuit The valve in addition to cylinder are mounted separately. (Vickers, 1967)

Integral Steering Unit S20 Steering Unit Consists of a power cylinder connected to a steering valve. Two external in addition to internal ports The inlet port is connected to the pressure line. The outlet port is the tank return. The upper internal port connects between the coaxial tubes of the cylinder to the cylinder rod end. The lower internal port connects to the head end of the cylinder. (Vickers, 1967) Integral Steering Unit View A The valve is in neutral position. The spool is centered, in addition to the oil from the pump is directed back to the tank View B The valve is in retract position. The spool is pushed to the left in addition to the oil is directed to the rod end of the cylinder, thus moving the steering unit to the left. View C The valve is in the extend position. The spool is moved to the right in addition to the oil is directed to the head end of the cylinder. The steering unit is moved to the right. (Vickers, 1967) Integral Steering Unit Check Valve Helps to avoid hydrostatic lock in addition to allow as long as manual steering Relief Valve Optional. Can be incorporated if the flow control in addition to relief valve is not used. Ball Stud mounting The control valve ball stud can be mounted in any four positions relative to the port connections. (Vickers, 1967)

Sagon, Erica Arizona Republic Fashion Reporter & Editor of

Remote Linkage System Auxiliary Side Ports (Vickers, 1967) Remote Linkage System Pitman Arm Stops Helps to protect against overheating. Adjusted so that the Pitman arm stops just be as long as e the wheels must stop. Should be used with any system that has a separate steering valve. (Vickers, 1967)

Sagon, Erica Fashion Reporter & Editor of “Yes”

Sagon, Erica is from United States and they belong to Arizona Republic and they are from  Phoenix, United States got related to this Particular Journal. and Sagon, Erica deal with the subjects like Fashion and Wearing Apparel; Fashion Industry; Retailing

Journal Ratings by Alfred Adler Graduate School

This Particular Journal got reviewed and rated by Alfred Adler Graduate School and short form of this particular Institution is US and gave this Journal an Excellent Rating.