1. Select the cylinder diameter bai

According to the load state of the cylinder, determine the axial load force F of the cylinder.

According to the motion state of the load, preselect the load rate η of the cylinder. dao

Based on the gas supply conditions of the gas source, determine the operating pressure P of the cylinder. P should be less than 85% of the inlet pressure of the pressure reducing valve.

Given F, η and P, for a single-acting cylinder, with the preset ratio of rod diameter to cylinder diameter d/D=0.5, the cylinder diameter D can be selected based on the calculation formula of the theoretical force of the cylinder and the load rate calculation formula mentioned earlier. For double-acting cylinders, the cylinder diameter D can be selected by using the calculation formulas for the theoretical force of the cylinder and the load rate mentioned earlier as well. The dimensions of cylinder diameter D should be standardized.

2. Select the cylinder stroke

Pre-select the stroke of the cylinder based on the operating distance of the cylinder and the stroke ratio of the transmission mechanism. To facilitate installation and commissioning, an appropriate margin should be left for the calculated stroke. It should be selected as the standard stroke as much as possible to ensure the supply speed and reduce the cost.

3. Select the type of cylinder

Based on the purpose of use and the required cylinder diameter and stroke as conditions, select the required cylinder type from the cylinder series.

4. Select the installation form

Different series have different installation forms, and each series also offers multiple installation forms to choose from. The installation form should be selected based on the different uses of the cylinder.

The installation forms include: basic type, foot base type, rod side flange type, rodless side flange type, single earring type, double earring type, rod side ear shaft type, rodless side ear shaft type, and central ear shaft type.

5. Select the buffer form

Select the buffer form of the cylinder according to the required application. The forms of cylinder buffering include: no buffering, rubber buffering, air buffering, and hydraulic buffering.

6. Selection of magnetic switches

The magnetic switch installed on the cylinder is mainly used for position detection. It should be noted that the built-in magnetic ring in the cylinder is a prerequisite for using a magnetic switch. The installation forms of magnetic switches include: steel band installation, track installation, pull rod installation, and true connection installation.

Supplementary Information

A cylinder is composed of a cylinder barrel, end covers, pistons, piston rods and seals, etc.

1) Cylinder barrel

The inner diameter of the cylinder barrel represents the magnitude of the output force of the cylinder. The piston should slide back and forth smoothly in the cylinder barrel, and the surface roughness of the inner surface of the cylinder barrel should reach Ra0.8μm.

The SMC and CM2 cylinder pistons adopt combined sealing rings to achieve bidirectional sealing. The pistons and piston rods are connected by rivets without nuts.

2) End cover

The end cover is equipped with intake and exhaust ports, and some also have a buffer mechanism inside the end cover. The side end cover of the rod is equipped with a sealing ring and a dust-proof ring to prevent air leakage from the piston rod and to prevent external dust from entering the cylinder. A guide sleeve is provided on the side end cover of the rod to improve the guiding accuracy of the cylinder, bear a small amount of lateral load on the piston rod, reduce the downward bend when the piston rod extends, and extend the service life of the cylinder.

Guide sleeves are usually made of sintered oil-impregnated alloys or forward-inclined copper castings. In the past, the end covers were commonly made of malleable cast iron. To reduce weight and prevent rust, aluminum alloy die-casting was often used. Some micro cylinders are made of brass.

3) Piston

The piston is the pressure-bearing part in the cylinder. To prevent gas leakage between the left and right chambers of the piston, a piston sealing ring is provided. The wear-resistant rings on the piston can enhance the guidance of the cylinder, reduce the wear of the piston sealing ring, and decrease the frictional resistance. Wear-resistant rings are made of materials such as polyurethane, polytetrafluoroethylene, and fabric-reinforced synthetic resin.

The width of the piston is determined by the size of the sealing ring and the necessary length of the sliding part. The sliding part is too short, which can easily cause early wear and jamming. The materials commonly used for pistons are aluminum alloy and cast iron. For small cylinders, the pistons are made of brass.

4) Piston rod

The piston rod is the most important force-bearing part in the cylinder. Usually, high-carbon steel is used, with its surface treated by hard chromium plating, or stainless steel is employed to prevent corrosion and enhance the wear resistance of the sealing ring.

5) Sealing ring

The sealing of components in rotary or reciprocating motion is called dynamic sealing, and the sealing of stationary parts is called static sealing.

The main connection methods between the cylinder barrel and the end cover are as follows:

Integral type, riveted type, threaded connection type, flange type, tie rod type.

6) When the cylinder is in operation, it relies on the oil mist in the compressed air to lubricate the piston. There are also a small number of self-lubricating cylinders.