Monthly Archives for May 2010

Hydraulic Servo Valve Port Shape

Servo valve bodies are machined with three common port shapes as shown in Fig. 11.13. The effect of port shape on flow is shown in Fig. 11.14. A full annulus port gives the highest flow per unit of spool displacement … Continue reading

15. May 2010 by and
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Jet Pipe Hydraulic Servo Valve Spool

The jet pipe design (Fig. 11.12) is less sensitive to contamination than the flapper nozzle. This design uses fluidics technology. A nozzle, attached to the armature, directs a stream of fluid (pressure Ps) at two receivers. When the nozzle is … Continue reading

15. May 2010 by and
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Double Flapper Nozzle Shifting Servo Valve Spool

A diagram of the double flapper nozzle is shown in Fig. 11.10. Supply pressure (the setting of the relief valve or the setting of a pressure compensated pump) is supplied to the points identified with Ps (Fig. 11.10). Fluid flows … Continue reading

14. May 2010 by and
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Hydraulic Servo Systems

There are four basic servo systems as shown in Fig. 11.7. The two servo-actuator systems are (1) valve-motor and (2) valve-cylinder. These systems are often referred to as servo motors and servo cylinders. The recommended procedure is to mount the … Continue reading

14. May 2010 by and
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Hydraulic Servo Valve Feedback

Feedback is an intuitive concept. Each time we reach for an object, we slow our hand as it approaches the object so that it is captured with minimal impact. There is visual feedback that our brain uses to control the … Continue reading

14. May 2010 by and
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Hydraulic Pilot-Operated Check Valve

The pilot-operated check valve is shown in Fig. 7.11. For flow in the forward direction, this valve operates just like a normal check valve. Pilot line pressure holds the valve open for fluid in the reverse direction. If the pilot … Continue reading

05. May 2010 by and
Categories: Linear Actuators | Tags: , | Leave a comment

Hydraulic Presses Machines Circuit

Presses are used for molding, shaping, shearing, and many other operations. Some of the older manufacturing plants have lines of presses connected in parallel as shown in Fig. 7.9. To give perspective to the problem, let us assume that the … Continue reading

05. May 2010 by and
Categories: Linear Actuators | Tags: , | 1 comment

Gear-Type Hydraulic Flow Divider

The gear-type flow divider functions like two gear motors with their shafts rigidly attached. We will consider first the case in which both motors have the same displacement. Since their shafts are attached, they both have to turn at the … Continue reading

05. May 2010 by and
Categories: Linear Actuators | Tags: , | Leave a comment

Orifice-Type Hydraulic Flow Divider

Theoretically, the orifice on both sides of the flow divider can be adjusted so that the ?P across the orifice plus the load ?P is equal on both sides. Then, the flow from the pump will divide equally, and both … Continue reading

05. May 2010 by and
Categories: Linear Actuators | Tags: , | Leave a comment

Servo Valve Electrical Circuit

Some explanation of the electrical circuit required for a servo valve is presented here to help readers understand how the servo valve in the servo pump operates when it is used in a closed-loop transmission.  The key features of the … Continue reading

05. May 2010 by and
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