SELECTION OF PNEUMATIC CYLINDERS （选择气动缸）.pdfVIP

SELECTION OF PNEUMATIC CYLINDERS • Single or Double acting • Dimensional standards like ISO, VDMA, CETOP, AFNOR. • Constructional details like – Piston rod, tie rod, square tube, Mickey mouse tube, rodless etc. • Force to be exerted (Bore dia) • Distance to be moved (stroke) • Surrounding medium (special material of construction / type of seals) • Air pressure available. • Cushioned / Non cushioned. • Ambient temperature for selection of seal material. • Speed of actuation • Position detection (Reed switch type) • Mountings • Stop tube length for long stroke cylinders. SPECIFICATION OF PNEUMATIC CYLINDERS Following points need to be considered while selecting a pneumatic cylinder. • Cylinder thrust. • Air consumption. • Piston velocity. • Type of mounting. • Couplings Cylinder Thrust The cylinder thrust is a function of : F = Cylinder thrust in Kg. D = Dia of piston in cm D = Dia of piston rod in cm. p = Operating air pressure in “bar”. f = Spring force in Kg. fr = frictional resistance.(Though in case of static thrust, the frictional resistance is zero.) Thrust exerted by various type of Cylinders: 1) Single acting push type: 2) Single acting pull type: 2 2 2 f f F = {π x D x P } − F = {π x (D – d ) x P } − 4 4 3) Double acting in forward stroke 4) Double acting in return stroke 2 2 2 F = {π x (D – d ) x P } F = {π x D x P } 4 4 Examples 1 To