Learn about "cylinder"
Definition: The part that constitutes the working volume with the piston.
A cylindrical metal part that guides the piston in a linear reciprocating motion. The working medium converts thermal energy into mechanical energy through expansion in the engine cylinder; the gas is compressed by the piston in the compressor cylinder to increase the pressure. Turbines, rotary piston engines, and the like are also often referred to as "cylinder." Applications of cylinders: printing (tension control), semiconductor (spot welding, chip grinding), automation control, robotics, etc. English name: cylinder
Cylinder type
Pneumatic actuators that convert the pressure energy of compressed gas into mechanical energy. The cylinder has two types of reciprocating linear motion and oscillating motion (see figure). The reciprocating linear motion cylinder can be divided into single acting, double acting, diaphragm type and impact cylinder.
1 single-acting cylinder: only one end has a piston rod, from the side of the piston to generate energy to generate air pressure, air pressure to push the piston to produce thrust out, return by spring or self-weight.
2 Double-acting cylinders: alternating air supply from both sides of the piston, output force in one or two directions.
3 Diaphragm Cylinder: The piston is replaced by a diaphragm and the force is only output in one direction and is reset with a spring. Its sealing performance is good, but the stroke is short.
4 Impact Cylinder: This is a new type of component. It converts the pressure energy of the compressed gas into the kinetic energy of the piston's high-speed (10 to 20 m/s) motion for work. The impact cylinder adds a middle cover with a spout and a vent. The middle cover and the piston divide the cylinder into a three-chamber of a gas storage chamber, a head chamber, and a tail chamber. It is widely used in various operations such as blanking, punching, crushing and molding. The oscillating cylinder is called a swing cylinder, in which the inner space is divided into two by a vane, and the two chambers are alternately supplied with gas. The output shaft is oscillating and the swing angle is less than 280°. In addition, there are rotary cylinders, gas-liquid damping cylinders, and stepping cylinders.
Cylinder effect
The pressure energy of compressed air is converted into mechanical energy, and the drive mechanism makes linear reciprocating, swinging and rotating motions.
Cylinder classification
Linear motion reciprocating cylinder, oscillating motion oscillating cylinder, gripper, etc.
Cylinder structure
The cylinder is composed of cylinder, end cap, piston, piston rod and seal. Its internal structure is shown in the figure:
1) cylinder
The cylinder bore size represents the output force of the cylinder. The piston should make a smooth reciprocating sliding in the cylinder, and the surface roughness of the inner surface of the cylinder should reach Ra0.8um. For steel tube cylinders, the inner surface should also be plated with hard chrome to reduce frictional resistance and wear, and to prevent corrosion. In addition to the use of high-carbon steel pipe cylinder material, or high-strength aluminum alloy and brass. Small cylinders use stainless steel tubes. For cylinders with magnetic switches or cylinders used in corrosion-resistant environments, cylinders should be made of stainless steel, aluminum alloy, or brass.
The SMC CM2 cylinder piston uses a combination of seals to achieve two-way sealing. The piston and the piston rod are riveted together without nuts.
2) End cap
The end cap is provided with an intake and exhaust vent, and some also have a buffer mechanism in the end cap. A seal ring and a dust ring are provided on the rod end cover to prevent air leakage from the piston rod and 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, to withstand a small amount of lateral load on the piston rod, to reduce the amount of downward deflection when the piston rod extends, and to prolong the service life of the cylinder. The guide sleeve usually uses sintered oil-containing alloys and forward-bent copper castings. The end caps used to be malleable cast iron in the past. Now, in order to reduce the weight and prevent rust, aluminum alloy die-casting is often used. The micro-cylinder is made of brass.
3) Pistons
The piston is a pressured part in the cylinder. In order to prevent the two chambers of the piston from purging each other, piston seals are provided. The wear ring on the piston can improve the guiding performance of the cylinder, reduce wear of the piston seal ring and reduce frictional resistance. The wear ring is made of polyurethane, PTFE, and cloth synthetic resin. The width of the piston is determined by the seal size and the necessary length of the sliding part. The sliding part is too short and can easily cause premature wear and seizure. The material of the piston is usually made of aluminum alloy and cast iron. The piston of the small cylinder is made of brass.
4) Piston rod
The piston rod is the most important part in the cylinder. High-carbon steel is usually used, the surface is plated with hard chrome, or stainless steel is used to prevent corrosion and improve the wear resistance of the seal ring.
5) sealing ring
Parts of a rotary or reciprocating seal are called dynamic seals. The seal of a stationary part is called a static seal.
There are mainly the following methods for connecting the cylinder tube and the end cap:
Integral type, riveted type, threaded connection type, flange type, tie rod type.
6) When the cylinder is working, the piston is lubricated by the oil mist in the compressed air. There are also a small number of lubrication-free cylinders.