SMC CY1S20-300Z Magnetically Coupled Rodless Cylinder

A sealed rodless cylinder for long, compact strokes

CY1S20-300Z is a magnetically coupled rodless cylinder of the SMC CY1S series, slider type with slide bearing. Inside the tube a piston carries a ring of magnets; an external slider outside the tube holds a matching magnet set and follows the piston. Because there is no rod passing through a seal, the tube is fully sealed, no air leaks along a rod, and the installed length is little more than the stroke plus the slider, so a long stroke takes up far less space than a conventional rod cylinder.

Decoding the part number: CY1S is the series (slider type, slide bearing), 20 is the 20 mm bore, 300 is the 300 mm stroke and Z is the design suffix. Because no piping, stopper or switch letters appear, it is the bilateral-piping version (ports at both ends), with the standard rubber bumper stopper and without auto switches; the catalogue says the auto-switch rail and the switch magnet are standard, so switches can be added later.

Technical specifications

Holding force is the limit, not thrust

The 231 N magnetic holding force is the load limit of the coupling. If the combined inertia and process force exceed it, the slider decouples from the piston and the catalogue warns that this can happen at high speed, with a heavy load or during sudden stops. The slider then has to be re-coupled by returning the piston, so the design must keep acceleration and any external force within the holding force with a margin, and use a shock absorber instead of the bumper for heavy masses.

The catalogue lists a wide family of sizes from 6 to 40 mm bore with holding forces from 19.6 N (6 mm) to 922 N (40 mm). A 20 mm unit is a mid-range choice for loads of a few kilograms moved horizontally on a transfer or pusher line.

Installation points

The slider carries a plate with mounting holes for the load, and the cylinder body is supported along the tube by brackets at intervals which depend on stroke and load; follow the catalogue support guidance for long strokes. Do not place magnetic material close to the tube, since external magnets or ferrous chips can interfere with the coupling or collect on the tube surface. Fit speed controllers on the exhaust side for smooth movement and keep air filtered and dry.

Variants listed in the catalogue by suffix, such as -X116 (air-hydro) or -X168 (helical insert thread), are separate part numbers from CY1S20-300Z.

Key features of the CY1S20-300Z

• Magnetic coupling between piston and slider, so the cylinder tube is completely sealed with no external rod seal.
• Slider type with integrated slide bearing, allowing light loads to be mounted directly on the slider table.
• Compact overall length relative to stroke, which suits machines where space along the axis of motion is limited.
• Non-lube operation, avoiding oil mist in the exhaust air near products or clean areas.
• Auto-switch rail and switch magnet as standard, so position sensing can be added at any time.
• Bilateral piping with ports at both ends of the tube.

Sizing checks before ordering

Selecting a magnetically coupled rodless cylinder is mainly a check of load and speed against the coupling and bearing limits, rather than a thrust calculation. SMC’s catalogue gives a selection procedure that should be followed for the actual mounting orientation.

1. Determine the load mass, its centre of gravity relative to the slider and the mounting orientation (horizontal, vertical or wall).
2. Check the allowable load mass and moments for the slide bearing at the required speed.
3. Confirm the kinetic energy at stroke end is within what the rubber bumper or the shock absorber option can absorb.
4. For vertical use, make sure the load is well below the magnetic holding force, as the catalogue gives specific limits for vertical operation.
5. Keep the piston speed within the 50 to 400 mm/s range; speed controllers on both ports help achieve smooth movement.

Maintenance and operating tips

• Supply clean, dry, filtered compressed air; moisture and particles shorten seal and bearing life.
• If the slider decouples from the piston after an overload or collision, follow the manufacturer’s procedure to re-couple it rather than forcing the slider by hand under pressure.
• Keep the outer surface of the tube clean, because dust or metal particles attracted by the magnets can affect the slider.
• Do not place the cylinder close to other strong magnetic fields or magnetic workpieces that could interfere with the coupling or auto switches.

Applications in Oman and the GCC

Rodless cylinders are used on packaging machines, pick-and-place transfers, sorting gates, door and gate openers on test cabinets, and light-load positioning in assembly lines. The sealed tube is a benefit in dusty environments common in the region, because there is no rod to drag particles into a seal. For food and beverage plants, the absence of oil in the exhaust is also an advantage.

The rated ambient range of -10 to 60 °C covers most indoor plants, but equipment inside unventilated enclosures or next to hot process equipment should be checked during summer. Pneumatic system leaks increase compressor running hours, so the leak-free tube design helps limit energy waste.

What to include in an RFQ

• Full part number CY1S20-300Z and quantity, plus any variant needed (centralised piping, shock absorber stopper or other stroke).
• Auto switch model and quantity, if position sensing is required.
• Load mass, orientation and speed if a selection check is wanted.
• Fittings, speed controllers and delivery location.

Documents and quotation

The SMC CY1S catalogue PDF linked here has the how-to-order page, specification tables, weights, shock-absorber data and dimensions. Please confirm piping type, stopper type, auto switches and mounting before ordering. Related products are under Pneumatic Cylinders. Seven Star LLC is an independent supplier and quotes the exact code on request.