The Differences of Double Acting Cylinder and Single Acting Cylinder

different types of air cylinder is produced by different manufacturers

Figure 1: Different types of air cylinder.

Single Acting Cylinder

Single-acting Cylinders have spring press-back type (S type) and spring press-out type (T type). Air enters from port A in S type, and air pressure drives the piston to overcome the spring force and friction, and the piston rod extends; when air exhausts form port A, spring force retracts the piston rod. Air enters from port A in T type, and the piston rod is retracted; A port exhaust, the spring force makes the piston rod extend. There is a breathing hole R on the side of the spring, and it is better to set a filter on the breathing hole to prevent pollutants from entering the cylinder.

Figure 2: The structure of S type single acting cylinder.

Single acting cylinder has simple structure and low air consumption. A spring is installed in the cylinder body to shorten the effective stroke of the cylinder. The reacting force of the spring increases with the increase of the compression stroke, so the output force of the piston rod decreases with the increase of the motion stroke. The spring has the ability to absorb kinetic energy and reduce the impact at the end of the stroke. It is generally used in occasions with short stroke and low requirements for output force and speed.

Double Acting Cylinder

The piston of a double-acting cylinder can output force (push or pull) either forward or backward. The structure is simple, and the stroke can be selected according to the needs. If the cylinder does not have a buffer device, when the piston moves to the end, especially the cylinder with a long stroke, the force of the piston hitting the cylinder head is very large, which is easy to damage the parts.

Figure 3: The structure of single piston rod type of double acting cylinder.

The introduction and brief description of double piston rod type of double acting cylinder

Figure 4: The structure of double piston rod type of double acting cylinder.

Double-acting cylinders are available in single-rod and double-rod types. The pressure area on both sides of the piston of the double piston rod type cylinder is equal, and the motion stroke and output force on both sides are equal. It can be used on the device of the long-stroke working surface. The two ends of the piston rod are fixed, the cylinder barrel moves with the working surface, the rigidity is enhanced, and the guidance is good. In order to absorb the impact energy of the cylinder moving parts at the end of the stroke, cushion pads are provided on both sides of the piston to protect the cylinder from damage.

Differences Between Double Acting Cylinder and Single Acting Cylinder

Different functions: the single acting cylinder acts on one end of the piston, while the double acting cylinder acts as one end of the piston.
Different uses: The single acting cylinder only transmits hydraulic fluid or output force in one direction. When in the cylinder, the piston rod can only be pushed outward rather than pulled inward. Therefore, a force in the opposite direction is required to return the piston rod to its original position. The double acting cylinder can transmit hydraulic oil or output force in the telescopic direction. The end ports are located at both ends of the cylinder, allowing the piston rod to move forward and backward.
Different advantages: single acting cylinder is simple in structure and affordable prices. While double-acting cylinder tends to be more energy-saving.