Components that convert compressed air energy to linear, oscillation, or
rotary motion are collectively called drive components (actuators).
Types of Actuators
For linear
motion
Air cylinders
For oscillating and
rotating motion
Rotary actuators
For oscillating and
rotating motion
Air motors
For
grasping
Hands, chucks, and grippers
Air cylinders
The following questions about air cylinders are explained here.
Q: How does the air cylinder move?
This is the internal structure of a typical double-acting air cylinder.
●Tube: A part that forms the cylinder chamber. It also serves as a sliding guide (*) for the piston. Cylinder piston sliding guide is also included.
●Cover: Parts forming an internal cylinder chamber such as supply and exhaust ports.
It is divided into a head cover and a rod cover.
●Tie rod: Fastens the cylinder tube to the cover.
●Piston: Slides inside the cylinder tube under air pressure.
●Piston packing: Prevents internal leakage of the cylinder.
●Piston magnet: A magnet to enable detection by the cylinder switch.
●Piston rod: Transmits piston output and displacement to the outside.
●Rod packing: Prevents air leakage from the piston rod gap.
●Bush: Sliding guide for piston rod.
*Sliding: moving an object by sliding it.
There are two types of actuator actuation methods:
(1) single acting type that outputs in only one direction and returns by external force or spring, and
(2) double acting type that outputs by air pressure in both directions, with the double acting type being the most common.
Air cylinders incorporate a cushion mechanism to prevent the piston and cover from being damaged by the impact of a load with inertia force on the cover when it stops at the end of its stroke.
(1) Air cushion mechanism
This mechanism utilizes the compressibility
of air pressure.
The cushioning capacity can be adjusted.
The cushion ring and cushion packing block the air disposal passage before the stroke end and are restricted only by the cushion needle. The piston back pressure(*) generated according to the adjustable amount is used as the cushion. *Back pressure: The pressure downstream of the object in the flow.
(2) Rubber cushion mechanism
Mechanisms that use elastic materials such as rubber.
The cushioning capacity cannot be adjusted.
Actuator size
Actuator size is indicated with the tube's inner diameter (bore size: the inner diameter).
The larger the tube's inner diameter, the larger the output.
Bore size has been standardized to JIS/ISO. CKD has specified Ø100 or more as the large bore size.
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