Abstract
A pneumatic control system of compressed air as a working fluid has a variety of advantages such as low price, high respondence, non-explosion and good control performance and thus has many applications in the field of automobile, electronic and semiconductor industry.
However, it has a difficulty in controlling a precise position due to quick response of system and compressibility of working fluid and, in particular, shock stress may occur due to an external load, resulting in fracture of a cap unless cushion device is equipped in the cylinder.
To avoid this, a cushion device should be installed for damping effect of the external load and supply pressure as for decreasing shock stress and vibration caused by high speed rotation.
Previous studies include dimensionless analyses and computer simulations of cushion capability and experiments of horizontally-mounted cylinder performance.
A new attempt is experimentally made in this study using a vertically-mounted cylinder under and operation condition of 4, 5 and 6 (bar) as supply pressure and 40, 70 and 100 (kgf) as external load.
It turns out that the cushion pressure is mainly a function of the external load rather than the supply pressure.
The cushion region characteristics was also revealed in the meter-in circuit.
