Pneumatic Cylinder

Overview

A pneumatic cylinder converts compressed air energy into linear mechanical motion. Double-acting cylinders, the most common type, have work ports on both the Head End Cap and Base End Cap, permitting powered extension and retraction. The Cylinder Barrel contains a sliding Piston Head connected to the Piston Rod Assembly, which extends through the head cap and transmits force to the load. Cushioning orifices at each end slow the piston near stroke limits, protecting against shock and noise.

How it works

Compressed air enters one work port under system pressure, pushing the Piston Head and Piston Rod Assembly outward. The air on the opposite side of the piston is expelled through its port. At stroke end, the Piston Head compresses against the Cushion Spear, which enters the Cushion Orifice and meters the exhaust air into a small metered path. This creates backpressure that decelerates the piston smoothly over the final 10–25 mm of travel. Pilot-to-open Check Valves in the cushion passages allow rapid free-flow return, so the load can move freely in the opposite direction without throttling.

The Magnetic Sensing Band, a ring neodymium magnet fixed to the Piston Head, rotates with the piston. External inductive or Hall-effect proximity sensors detect this magnet at any cylinder position, providing position feedback without requiring rod-mounted cable or mechanical feedback devices. This is the standard end-of-stroke detection method in automated systems.

All wetted parts are sealed with polyurethane rings in the Piston Head and Rod Seal to prevent air leakage. Static O-rings seal the Port Assembly connections. The Cylinder Barrel is anodized and honed to a mirror finish so the Piston Head slides smoothly across millions of cycles with minimal friction. The chrome-plated Piston Rod Assembly resists corrosion and scoring from side loads.

Assembly and maintenance

The Seal Kit packages replacement seals for field rebuild. Cylinder maintenance involves draining condensate from the supply line, keeping air filters clean, and (after 5–10 million cycles) disassembling the end caps to replace worn seals and wipers. Cushion valves may require adjustment if the load decelerates too quickly or the piston slams; a needle adjustment valve limits flow through the Cushion Orifice.

Standard bore and rod sizes follow ISO 6432, making cylinders interchangeable across manufacturers. Pressure-rated design is typically 10 bar, though some specialized cylinders operate to 25 bar.