Hydraulic cylinders can be divided into single-acting and double-acting types according to the hydraulic pressure, today we will learn about the types and uses of single-acting hydraulic cylinders!

Single-acting hydraulic cylinders can only exert force in one direction. The piston can only be reset with the help of a spring, or by the weight of the piston, or by external force. Single-acting hydraulic cylinders basically have only one effective action area.

Single-acting hydraulic cylinders can be divided into rod-type hydraulic cylinders, spring-return hydraulic cylinders and other special forms of single-acting hydraulic cylinders according to their structure and reset form.

1.Rod-type hydraulic cylinder

As shown in the figure above, the left hydraulic cylinder only has a piston rod and no internal stop device, while the right hydraulic cylinder has a piston and an internal stop device. When the hydraulic oil enters the hydraulic cylinder from port “A”, the piston rod extends outward on the effective area of the hydraulic cylinder. This type of cylinder can only generate thrust.

The piston can only be reset by its own weight or by applying an external force.

Depending on the application, rod-type hydraulic cylinders can be with or without internal travel limiters and guide pistons. For this type of hydraulic cylinder, the size of the hydraulic pressure generated is the product of the area of the piston rod cavity and the working pressure.

This type of single-acting hydraulic cylinder is generally used in cutting tables, lifting equipment, and large hydraulic press master cylinders, etc.

Note: The weight of the single-acting hydraulic cylinder plunger used in large equipment is often large. When placed horizontally, it is easy to sag due to its own weight, resulting in unilateral wear of the seal and guide device. The secret of hydraulic cylinder failure is revealed! All the maintenance methods are here! Therefore, in actual use vertical use, it is more conducive to extending the service life of the hydraulic cylinder.

2.Spring return hydraulic cylinder

As shown in the figure above, spring return push rod hydraulic cylinders are divided into internal spring return type (left picture) and external spring return type (right picture).

The hydraulic oil enters the hydraulic cylinder from port “A” and acts on the effective area of the hydraulic cylinder, causing the piston rod to extend outward.

The retraction of the piston rod depends on the return spring.

As shown in the figure above, spring return tie rod hydraulic cylinders can be divided into internal spring return type (left picture) and external spring return type (right picture).

If the hydraulic oil enters the hydraulic cylinder from the “B” port and acts on the effective area of the hydraulic cylinder, the piston rod will retract inward.

The extension and reset of the piston rod depends on the return spring.

Spring return hydraulic cylinders are used in situations where there is no external return force. The return spring can be installed inside the cylinder body or as an independent component of the hydraulic cylinder. Since springs can only produce a limited stroke and force, they are often used in “small hydraulic cylinders”. Application examples include clamping cylinders during installation and maintenance and assembly machinery.

3. Special form of single-acting hydraulic cylinder

1. Single-acting telescopic hydraulic cylinder

When hydraulic oil enters the cylinder from port “A”, the pistons extend in sequence (as shown in the right figure). The lifting pressure is determined by the load size and the effective area. Therefore, the piston with the largest effective area extends first. Under constant pressure and flow, the initial extension force is the largest and the speed is the smallest. The last extension force is the smallest and the speed is the highest.

The propulsion force must be calculated based on the smallest effective area. For single-acting telescopic hydraulic cylinders, the order of retraction is opposite to that of extension, that is, the piston with the smallest effective area returns to the starting position first.

2.Single-acting quick-reset hydraulic cylinder

Quick action: The hydraulic oil pushes the piston to move quickly through the “A1” port, and needs to be sucked from the “S” port to prevent the formation of a vacuum; when continuous clamping force is required, the hydraulic oil enters from “A2” and acts on a large area to provide high pressure.

When retracting due to self-weight or external force, the oil returns from the “A1” and “A2” ports to achieve the effect of quick retraction.

Contact: Nancy Zhu, Sales manager, JW GROUP.

Email: nancy@jwgroup.cc

Web: https://jwcylinder.com

Mobile/Whatsapp:+86 15902166721

HYDRAULIC CYLINDER and CNC parts specialist

JW GROUP is an integrated steel product group, products include: hydraulic cylinder, hydraulic cylinder spare parts, drilling forging parts, pneumatic actuator-scotch yoke, CNC machinery parts etc.