Abstract

 
 
 Electro-hydraulic servo valves (EHSVs) serve as an interface between electrical devices and hydraulic systems. They are capable of converting low power electrical input into movement of a spool to control precisely high power, low speed hydraulic actuators. Nowadays, jet pipe electro-hydraulic servo valve and flapper nozzle electro-hydraulic servo valve are typical two-stage control flow servo valve and are the most popular in use. This paper recommends and compares characteristics, working principle and structure for two kinds of servo valve. Besides, the simulation was carried out in a commercially software of Ansys, hence some features of jet pipe servo valve such as outstanding advantages of working feature or reliability are analysed. 
 
 
Highlights
Nowadays, jet pipe electro-hydraulic servo valve and flapper nozzle servo valve are two kinds of servo valve which are the most popular in application for air-force, aviation industry or universe industry
2.1 Flapper nozzle electro-hydraulic servo valve In Fig.1, sketch diagram of working principle for flapper-nozzle electro-hydraulic servo valve is Manuscript Received on May 16th, 2016, Manuscript Revised February 22nd, 2017
Valve spool draws small ball of spring pole, simultaneously feedback moment is formed at modulus of armature-flapper
Summary
Jet pipe electro-hydraulic servo valve and flapper nozzle servo valve are two kinds of servo valve which are the most popular in application for air-force, aviation industry or universe industry. Working principle: when input an electric control signal to the coil of torque motor, immediately at two ends of armature, magnetic force is formed, as a result, modulus of the armature is deflected. One side of flapper-nozzle can do orifice become small, so force of hydraulic resistance is bigger and back-pressure from the orifice increases. Back-pressure from the orifice can be changed correlatively with the change of position of flapper. Valve spool draws small ball of spring pole, simultaneously feedback moment is formed at modulus of armature-flapper. When feedback moment gradually decreases to equal to magnetic moment, modulus of armature-flapper moves gradually to null position. Valve spool can stop anywhere that feedback moment equals to TẠP CHÍ PHÁT TRIỂN KH&CN, TẬP 20, SỐ K1-2017 magnetic moment established from input an electric control signal. When oil supply pressure and load pressure are constant, the load flow at the output is proportional to position of valve spool [2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
