Gao Han

A nozzle flapper electro-pneumatic proportional pressure valve driven by piezoelectric motor

Electro-pneumatic proportional valve, as an important electro-pneumatic conversion element in pneumatic technology, has been widely applied in many pneumatic servo control systems. A novel nozzle flapper electro-pneumatic proportional pressure valve driven by piezoelectric motor instead of the traditional torque motor was proposed in this paper. The structure and working principle of this type electro-pneumatic proportional pressure valve were described. And a mathematical model was established. A testing system was developed and the prototype valve was tested. Test results showed that under the 0.3 MPa working pressure, an output performance of linearity ±0.5%, resolution 0.1%, hysteresis ±0.5% were obtained.

Influence of ultrasonic oscillations on static friction characteristics of pneumatic cylinder

Based on the friction reduction effect of ultrasonic oscillations, ultrasonic oscillations are utilized to vibrate the cylinder outside barrel, and the static friction characteristics of pneumatic cylinder under ultrasonic oscillations have been investigated. The cylinder sample employed is a standard double rod cylinder with a cube body, and the ultrasonic oscillator has a measured resonant frequency of 31.65 kHz. The two components are connected through screw thread for effective oscillations. A measurement system is established and the influence of ultrasonic oscillators frequency, exciting voltage and relative exciting position on static friction characteristics is explored. The experiment results prove the existence of cylinder friction reduction with ultrasonic oscillations compared to that of non-oscillation. And the static friction can be reduced to 60% of non-oscillation friction around the oscillators resonant frequency.

Influence of Ultrasonic Vibrations on the Static Friction Characteristics of a Rubber/Aluminum Couple

A novel ultrasonic vibration approach is introduced into a chloroprene rubber/aluminum friction couple for improving the static friction properties between rubber and metal. Compared to the test results without vibrations, the static friction force of a chloroprene rubber/aluminum couple decreases observably, leading to the ultimate displacement of rubber. The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations, respectively.

Research on Pneumatic Cylinder Static Friction and Ultimate Displacement Upon Ultrasonic Vibrations

This article introduced ultrasonic vibrations upon the outside barrel of pneumatic cylinder, and had an investigation on the influence of ultrasonic vibrations on cylinder static friction and ultimate displacement in working condition. In the related experiments, ultrasonic vibrator is connected to the upper surface of cylinder tightly, with the resonant frequency of 31.65 kHz. A test system of cylinder friction upon ultrasonic vibration was established and the influence of vibration frequency, exciting voltage, and compressed air pressure on static friction characteristics was researched in working condition. The results can reveal that, the vibrations can decrease the static friction sharply towards less than 40% of the non-vibration friction, while the ultimate displacement be reduced to 25% of the original one. Also, the friction-reduction effect shows the best influence in the resonant frequency range. The static friction increases as the air pressure goes up, without reference to the friction reduction by ultrasonic vibrations.