Monthly Archives for May 2010

Pump Displacement Control

A variable displacement pump is more expensive, but it adds tremendous options for the design of a fluid power circuit. A servo valve can be used to change pump displacement and thus change actuator speed. The open-loop system shown in … Continue reading

14. May 2010 by Jack
Categories: Servo Valves | Tags: | Leave a comment

Hydraulic Radial Piston Motors

Radial piston motors produce very high torque at low speed. They are used as wheel motors for large equipment. Pistons operate in radial bores in a stationary cylinder block. The surrounding housing rotates (Fig. 5.18). The rotating housing has two … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Bent Axis Motor Design

The piston shaft (tapered section shown in Fig. 5.15) does not provide the linkage that ensures that the cylinder block rotates with the output shaft. This linkage is provided with another mechanism. Different manufacturers use various mechanisms to develop this … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Bent Axis Motors

Bent axis motors were developed to improve the operating and stall torque efficiencies of high-speed motors. The design (Fig. 5.15) operates in a manner similar to that of the axial piston design. A series of cylinders are mounted around the … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Vane Motor Performance Characteristics

The Vickers Model MHT50 vane motor with 38 in3/rev maximum displacement was chosen for an example. This motor is rated for a maximum pressure of 4000 psi. Maximum continuous speed at 3000 psi is 200 rpm and maximum speed at … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: , , | Leave a comment

Hydraulic Geroler Motor Performance Characteristics

The Char-Lynn 10,000 series motor with 40.6 in3/rev displacement was chosen for an example. (Notice that this displacement is approximately 10 times the displacement of the high-speed motors previously studied.) This motor has a maximum speed of 254 rpm for … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Piston Motor Efficiency

The fixed displacement axial piston motor (Sauer-Danfoss Model 90-075 MF), comparable to the variable displacement axial piston pump (Sauer-Danfoss Model 90-075 PV), was chosen. This motor has a maximum speed of 3950 rpm and a rated pressure of 6000 psi. … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Vane Motor Efficiency

A Vickers Model 25M (65) vane motor was chosen for the comparison. This motor is rated for 3000 rpm at 2500 psi maximum pressure. It has a displacement of 4.19 in3/rev. Efficiencies were calculated for a 35 GPM input flow. … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydraulic Gear Motor Efficiency

The gear pump design can also be used as a motor. The Hydreco Model 1919 motor has a theoretical displacement of 4.53 in3/rev, a maximum pressure rating of 2500 psi, and 3000 rpm maximum speed rating. Efficiencies were calculated for … Continue reading

07. May 2010 by Jack
Categories: Rotary Actuator | Tags: | Leave a comment

Hydrostatic Drive for Sweet Sorghum Harvester

An experimental vehicle to harvest whole-stalk sweet sorghum was designed by a university research team. At present, the harvester is a pull-type machine, meaning it is towed behind a tractor and powered via a universal joint driveline. The decision has … Continue reading

05. May 2010 by Jack
Categories: Hydrostatic Transmissions | Tags: , | Leave a comment

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