OEM Double Acting Forklift Hydraulic Cylinder

A single-acting cylinder can only push — gravity or a spring must provide the return force. A double acting hydraulic cylinder pushes and pulls under full hydraulic control, making it essential for every forklift function where the load direction reverses: tilting the mast forward and backward, steering the wheels left and right, spreading and closing fork positioner arms, and operating clamp, rotator, and side-shifter attachments. Without double-acting capability, none of these functions can be powered in both directions from the operator's seat.

Korea Ever-Power manufactures this cylinder as an OEM product — built to your drawing or engineered from your application requirements. The 25-component piston cylinder architecture accepts any bore from Φ25 to Φ200, any stroke length, and any working pressure up to 35 MPa. Premium seal options from Parker, NOK, Hallite, and Busak Shamban match the global OEM seal standards used by every major forklift manufacturer. Whether you need 1 prototype or 100,000 annual production units, this platform delivers the same quality at every scale.

Extend Stroke (Cap End Pressurised)

Oil acts on the full bore area (π × D²/4). This is the maximum force direction. On a Φ80 bore cylinder at 18 MPa: F = 18 × π × 40² / 10 = 90.5 kN. This force tilts the mast forward, pushes the fork positioner arms apart, or extends the side-shifter carriage.

Retract Stroke (Rod End Pressurised)

Oil acts on the annular area (bore area minus rod area). Force is always lower than the extend force. On the same Φ80/Φ50 cylinder: F = 18 × π × (40² − 25²) / 10 = 55.1 kN. This force tilts the mast backward, closes the positioner arms, or retracts the side-shifter. The force ratio (extend/retract) is approximately 1.64:1 for this bore-to-rod combination.

What is the difference between this OEM cylinder and the standard catalogue tilt cylinder?

The standard tilt cylinder has fixed bore, stroke, and mounting dimensions — you choose from 7 predefined models. This OEM cylinder has no fixed dimensions — every parameter is manufactured to your specification. Both use the same 25-component architecture, the same production lines, and the same quality process. The OEM option exists for applications where no standard model matches your vehicle's geometry, or where your supply chain requires a specific seal brand, surface treatment, or branding that the standard catalogue does not offer.

Can you produce a double-acting cylinder with cushioning at end-of-stroke?

Yes. End-of-stroke cushioning (deceleration before the piston reaches the end cap) is available on both the extend and retract ends, or on one end only. The cushion uses a tapered spear or stepped collar on the piston that progressively restricts the oil exit port as the piston approaches the end of stroke, creating a decelerating pressure buildup that absorbs the kinetic energy of the moving piston and load. This is specified for high-speed double-acting applications where uncontrolled end-of-stroke impact would damage the cylinder or the machine structure.

What is the difference between 20# steel and 45# steel for the cylinder body?

20# is a low-carbon steel (approximately 0.20% carbon) with good weldability and adequate strength for pressures up to 25 MPa at standard wall thicknesses. 45# is a medium-carbon steel (approximately 0.45% carbon) with higher tensile and yield strength — allowing thinner wall sections at the same pressure rating, which reduces weight and overall diameter. 45# requires more careful welding procedures (preheat and post-weld heat treatment) and costs approximately 15–20% more in raw material. For most forklift tilt and steering applications at 18 MPa, 20# steel provides sufficient strength at lower cost. For high-pressure or weight-critical applications, 45# provides the performance advantage.

What information do I need to provide for an OEM quotation?

At minimum: bore diameter, rod diameter, stroke, working pressure, mounting type (both ends), port thread standard, and port positions. Additionally helpful: seal brand preference, surface treatment, annual volume estimate, target unit price (if any), and the equipment make/model the cylinder serves. The more information you provide upfront, the faster the quotation and the fewer clarification rounds required. Submit your specification via the Korea Ever-Power inquiry form or directly by email with your drawing attached.

Is the warranty coverage the same as the standard catalogue products?

Yes. All Korea Ever-Power cylinders — standard and custom, single-acting and double-acting — carry a 1-year warranty against manufacturing defects in materials and workmanship when operated within the agreed specification. The warranty covers the cylinder housing, piston rod, all seals, and all internal hardware. It does not cover damage from operation above the rated pressure, use of incompatible hydraulic fluids, or physical damage from external impact.