The cylinder is a pneumatic actuator that converts the pressure energy of compressed air into mechanical energy to achieve linear reciprocating movement or swing. In the industrial field, cylinders are widely used in many industries such as automated production lines, mechanical equipment, automobile manufacturing, food packaging, etc. due to their advantages of simple structure, reliable operation, convenient maintenance, and low cost. They are important components for achieving automated operation and precise control, and play a crucial role in improving production efficiency, reducing labor intensity, and ensuring product quality.
I. Working principle
Single acting cylinder
The single acting cylinder has only one air chamber inside and relies on spring force, gravity or other external forces to achieve reset. When compressed air is introduced into the rod chamber or rod-less chamber of the cylinder, the piston overcomes external forces such as spring force and extends outward under the action of air pressure, pushing the load to move. After the gas source is cut off, the piston returns to its initial position under the action of external forces such as springs.
Double acting cylinder
The double acting cylinder has two chambers located on either side of the piston. By controlling the intake and exhaust of two chambers, bidirectional movement of the piston is achieved. When compressed air is introduced into the rod-less chamber, the rod-less chamber exhausts and the piston extends. On the contrary, when compressed air is introduced into the rod chamber, the rod-less chamber exhausts, and the piston retracts. The extension and retraction of the piston are driven by air pressure.
II. Application Scenarios
Single acting cylinder
- Automatic door control: In some small automatic door systems, a single acting cylinder can use spring reset to achieve automatic opening and closing of the door, with a simple structure and low cost.
- Simple clamping device: In some fixtures that do not require high clamping force and only require one-way clamping, the single acting cylinder can release the workpiece through spring reset, making the operation convenient.
- Simple push in the light industry: In some light industry production lines, such as small packaging push for food and medicine, a single acting cylinder can complete a simple push action, using a spring reset to prepare for the next push.
Double acting cylinder
- Industrial robot arm: Industrial robot arms require precise motion and positioning in multiple directions, and dual acting cylinders can provide bidirectional driving force to meet the control requirements of robot arms in different positions and postures.
- Assembly equipment for automotive production lines: In processes such as engine assembly and body welding, double acting cylinders are commonly used to drive various fixtures, positioning devices, and assembly tools, enabling high-precision positioning and powerful clamping and assembly actions.
- Machine tool worktable movement: The feed and retraction of the machine tool worktable require precise control, and the double acting cylinder can achieve smooth and accurate movement of the worktable in two directions through precise air path control.
III. Selection Guide
- Load: Select the cylinder according to the actual size of the load to be pushed or pulled. In general, double acting cylinders can provide greater output force than single acting cylinders under the same cylinder diameter. If the load is large and bidirectional driving is required, double acting cylinders are more suitable. If the load is small and only one-way action is required, a single acting cylinder may be able to meet the requirements.
- Speed: The movement speed of the cylinder is related to factors such as gas supply and load size. The speed control of double-acting cylinders is relatively more flexible when moving in both directions, and the speed can be accurately controlled by adjusting the intake and exhaust flow of the two air chambers. The speed of a single acting cylinder is mainly affected by the intake flow rate and the spring return speed. If high speed requirements are needed and bidirectional variable speed control is required, a double acting cylinder is more optimal.
- Stroke: Select the length of the stroke according to the actual work requirements. In general, both single acting cylinders and double acting cylinders can meet the requirements of different strokes, but in long stroke applications, the stability of double acting cylinders may be better because their bi-directional forces are more balanced.
- Working environment: If the working environment is harsh, such as high temperature, humidity, corrosive gases, etc., it is necessary to choose cylinders with corresponding protection levels. In some situations where explosion prevention is required, it is also necessary to choose explosion-proof cylinders. In addition, if the space is limited and the single acting cylinder structure is relatively simple, it may be easier to install.
- Control requirements: If precise position control and bidirectional action control are required, a double acting cylinder combined with corresponding control valves and sensors can better achieve them. If the control requirements are simple, only one-way action and reset need to be implemented, and a single acting cylinder with simple control components can meet them.
IV. Maintenance recommendations
- Regular cleaning: Regularly clean the dust, oil stains, and debris on the surface of the cylinder to prevent them from entering the interior of the cylinder and affecting its normal operation.
- Check the seals: Regularly check the seals of the cylinder for wear, aging, or damage. If there are any problems, replace them in a timely manner to prevent gas leakage and ensure the performance of the cylinder.
- Lubrication and maintenance: Regularly lubricate the moving parts of the cylinder according to its usage requirements. Appropriate lubricating oil or grease can be used to reduce friction and extend the service life of the cylinder.
- Check the air system: Check for leaks, blockages, and other issues in the air pipeline to ensure smooth air flow. At the same time, check whether pneumatic components such as solenoid valves, pressure reducing valves, etc. are working properly, and repair or replace them in a timely manner if there are any faults.
- Pressure monitoring: Regularly monitor the working pressure of the cylinder to ensure that it works within the specified pressure range to avoid cylinder performance degradation or damage due to excessively high or low pressure.
When choosing a single acting or double acting cylinder, factors such as load, speed, stroke, working environment, and control requirements should be comprehensively considered.
To select single or double cylinders, load, speed, stroke, working environment, control requirements and other factors should be considered. You can refer to the manufacturer’s technical data and case study when selecting the type, and welcome to consult HANUMAN, HANUMAN will select the right cylinder for you!
