What are the classification types of pneumatic actuators?

Pneumatic actuators is an actuator that converts gas energy into mechanical energy to realize reciprocating motion or rotary motion. The pneumatic actuator that realizes linear reciprocating motion is called cylinder; Rotary motion is called pneumatic motor.

According to the control information from the controller. It converts electric energy or fluid energy into mechanical energy or other forms of energy, and changes the mechanical motion state or other states (such as temperature and pressure) of the controlled object according to the control requirements. It acts directly on the controlled object and can play the role of "hand" and "foot".

Classification of pneumatic actuators:

1, cylinder

It is the main executive component in pneumatic transmission, which is divided into single-acting and double-acting in basic structure. The compressed air of the former enters the cylinder from one end to make the piston move forward, and the piston returns to its original position by spring force or self-weight at the other end; The reciprocating motion of the piston in the latter cylinder is driven by compressed air. The cylinder consists of a front end cover, a rear end cover, a piston, a cylinder barrel, a piston rod and the like. Generally, 0.5 ~ 0.7 MPa compressed air is used as the power source of the cylinder, and the stroke ranges from several millimeters to several hundred millimeters, and the output thrust ranges from dozens of kilograms to dozens of tons.

With the expansion of the application scope, new structures of cylinders are constantly emerging, such as stroke control cylinder, gas-liquid feeding cylinder, gas-liquid stepping feeding cylinder, reciprocating rotation cylinder and so on. They have been widely used in mechanical automation and robots. Oil-free cylinders and small lightweight cylinders are also under development.

2. Pneumatic motor

It can be divided into swing type and rotary type, the former realizes limited rotary motion, and the latter realizes continuous rotary motion. There are two types of swing pneumatic motors: vane type and screw type. Screw pneumatic motor converts the linear motion of piston into rotary motion by using screw. Compared with the vane type, it has a slightly larger volume, but good sealing performance. The rotary motor relies on the pin shaft installed on the shaft to transmit torque. When it stops rotating, there is a great inertial force acting on the axis. Even if the buffer device is adjusted, this influence cannot be eliminated. Therefore, it is necessary to use oil buffer or set external buffer device.

The rotary pneumatic motor can realize stepless speed regulation, and the power and speed can be adjusted by controlling the gas flow. It also has overload protection function. When the motor is overloaded, only reduce the speed or stop, but do not exceed the rated torque. There are two common rotary pneumatic motors: vane type and piston type. The piston type has higher torque than the vane type, but the vane type has higher rotational speed; The sealing between the vane and stator is difficult, so the efficiency is not high at low speed, and it can be used to drive the opening and closing mechanism of large valves. Piston pneumatic motor is used to drive rack and pinion to drive load to move.