for the executing elements of the system. This section focuses on the analysis of the
reasons and characteristics of pneumatic cylinder widely used in servo control.
The types of cylinders can be distinguished according to the mode of air supply,
the formation of cylinder piston rod, the sealing method and whether there are
buffers or not. Figure 8.10 shows the structure of the double piston rod and single
piston rod cylinder.
There is also a corrugated diaphragm (or film) cylinder in the cylinder series.
Figure 8.11 shows the structure of this kind of cylinder. Obviously, the greatest
advantage of this kind of corrugated diaphragm cylinder is that the friction between
moving parts is almost imperceptible and there is no internal leakage. Of course,
this kind of corrugated diaphragm cylinder is only suitable for small stroke control
system.
The working process with buffer groups can be referred to in Figs. 8.9 and 8.12.
When the piston approaches the end of the cylinder quickly, before the piston stroke
is over, in order to absorb the kinetic energy of the piston that the piston speed is
reduced to prevent the piston from hitting the cylinder head, at the moment that the
piston approaches the end of the cylinder head stroke, the sealing ring of the small
piston of the buffer blocks the exhaust hole of the end cap and the passage of the
cylinder capacity chamber. The gas enclosed at the end of the cylinder can only be
throttled out to the outside of the cylinder through a needle valve. At this time, the
piston compresses the gas enclosed at the end of the cylinder, which produces a
cushioning and braking effect, so that the piston reduces speed and meets the
requirement of preventing the piston from colliding with the end cap.
After the cylinder completes the left stroke, the piston moves to the opposite
direction (Fig. 8.12). The airflow enters the chamber at the end of the small piston
of the buffer through the inlet hole. Except for part of the airflow enters the chamber
Needle valve
(a)
(b)
Fig. 8.10 Structural sketch of double piston rod (a) and single piston rod (b) cylinder
Corrugated film
Reset spring
Piston rod
Fig. 8.11 Principle of
corrugated diaphragm
cylinder
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8 Pneumatic Actuators, Driving Elements and Accessories
reasons and characteristics of pneumatic cylinder widely used in servo control.
The types of cylinders can be distinguished according to the mode of air supply,
the formation of cylinder piston rod, the sealing method and whether there are
buffers or not. Figure 8.10 shows the structure of the double piston rod and single
piston rod cylinder.
There is also a corrugated diaphragm (or film) cylinder in the cylinder series.
Figure 8.11 shows the structure of this kind of cylinder. Obviously, the greatest
advantage of this kind of corrugated diaphragm cylinder is that the friction between
moving parts is almost imperceptible and there is no internal leakage. Of course,
this kind of corrugated diaphragm cylinder is only suitable for small stroke control
system.
The working process with buffer groups can be referred to in Figs. 8.9 and 8.12.
When the piston approaches the end of the cylinder quickly, before the piston stroke
is over, in order to absorb the kinetic energy of the piston that the piston speed is
reduced to prevent the piston from hitting the cylinder head, at the moment that the
piston approaches the end of the cylinder head stroke, the sealing ring of the small
piston of the buffer blocks the exhaust hole of the end cap and the passage of the
cylinder capacity chamber. The gas enclosed at the end of the cylinder can only be
throttled out to the outside of the cylinder through a needle valve. At this time, the
piston compresses the gas enclosed at the end of the cylinder, which produces a
cushioning and braking effect, so that the piston reduces speed and meets the
requirement of preventing the piston from colliding with the end cap.
After the cylinder completes the left stroke, the piston moves to the opposite
direction (Fig. 8.12). The airflow enters the chamber at the end of the small piston
of the buffer through the inlet hole. Except for part of the airflow enters the chamber
Needle valve
(a)
(b)
Fig. 8.10 Structural sketch of double piston rod (a) and single piston rod (b) cylinder
Corrugated film
Reset spring
Piston rod
Fig. 8.11 Principle of
corrugated diaphragm
cylinder
14
8 Pneumatic Actuators, Driving Elements and Accessories