Pneumatic cylinder: specifications

Pneumatic cylinder - one of the components of the pneumatic drive, designed to move the working element of different machines and mechanisms.

Air cylinder construction

The design of the pneumatic cylinder, unlike the rotary actuators, is much simpler and consists of a hollow shell inside which, under the pressure of compressed air, the rod moves, creating a retracting and pushing action on the mechanism.

Dampers are used to lower the impact load at the end of the stroke of the rod. If the impact energy is small, then this role is assigned to the rubber rings. In large cylinders, a system is used to remove a part of the air with its further withdrawal through the throttle.

Varieties of cylinders according to the principle of operation

Pneumatic cylinder, depending on the principle of operation can be of several types:

1. The cylinder of one-sided action is presented above.
2. Double-acting cylinder you can see in the photo below.

The design of a single-sided cylinder implies the presence of only one inlet opening, respectively, the mechanism travels only in one direction, unlike a double-sided cylinder. Inlets in the double-sided cylinder are located on both sides, so that the working stroke is made in two directions.

Varieties of cylinders according to the number of piston positions

Pneumatic cylinder is divided into several types depending on the final position of the piston:

1. Two-position, having two fixed extreme positions.
2. Multi-position, in which the operating mechanism can be fixed in different positions between the two extreme positions.

Structural features of cylinders

Pneumatic cylinders, depending on the purpose, can differ in the design and execution of its individual elements.

For example, actuators with a double stem are used in mechanisms that require high resistance to lateral loads. It is provided by fastening the rod to two supports, located at a great distance from each other.

A pneumatic cylinder with a turn-protected stem is used when the tool is attached to it. Special flat bevels, clinging to the guide element, limit the maximum permissible torque.

Flat designs, equipped with flattened sleeves, are used to save space and protect the cylinder housing from turning.

Tandem cylinder is used to increase the force while maintaining the diameter of the sleeve. The construction of such cylinders consists of two cylinders arranged in a longitudinal plane, having a common rod. In the cavity of the parts at the same time, pressure is applied, which makes it possible to increase the force on the rod by two times.

The current position of the cylinder is determined by means of special magnetic rings. Electromagnetic sensors fix their position and, accordingly, the fact that the rod is in a certain place.

The principle of the pneumatic cylinder

The operation of the pneumatic cylinder is based on the effect of compressed air on the piston of the pneumatic cylinder. The impact can be either unilateral or bilateral. Depending on this pneumatic cylinders are of two types - one-sided and two-way.

In the case of unilateral action, the air flow is effected only in one of the working cavities of the mechanism, respectively, the piston moves under the action of compressed air in only one direction. In the opposite direction, the piston moves by means of a spring, which is mounted inside the second working surface on the cylinder rod.

Single-sided pneumatic cylinders are divided into several categories: with a normally extended and normally retracted stem.

The movement of the rod in the double-acting pneumatic cylinders is carried out in two directions by the action of compressed air, which is supplied to one of the working areas. The air is distributed between the cavities using a pneumatic distributor.

Features of the structure of pneumatic cylinders

The pneumatic brake cylinder consists of a sleeve, piston rod, stem and flanges. For each of the listed elements, their design features are characteristic, on which depends how the pneumatic cylinder will function. Detailing of such details is carried out after specification of all design features.

Pneumatic cylinders are made of smooth pipes or profiled pipes, which include aluminum alloys. The main difference between these two parts is the presence of special grooves in the profiled pipe, which are intended for mounting reed sensors.

Pistons of pneumatic cylinders are equipped with magnetic rings that interact with reed sensors.

The main design feature of the flanges of pneumatic cylinders is an adjustable damper.

The surface of the flange is protected from possible impacts of the piston by means of a brake mechanism located at the end of the working stroke. This mechanism is, in fact, a damper. The speed of braking is regulated by a throttle built into the flanges of the cylinder.

Pneumatic cylinders, actuators in most cases are selected using the calculation method. In addition, special computer programs are often used for this purpose.

The calculation method is based on the effort that develops in the part rod. It depends directly on the diameter of the piston, frictional forces and working pressure. In determining the theoretical effort, only the axial force on the stationary rod is considered without taking friction forces into account. The force on the rod is different for the double acting cylinders when the rod is retracted and retracted and for unilateral action with spring return.

Pneumatic brake servo

Pneumatic amplifiers are used to convert compressed air energy into the required fluid pressure in the hydraulic brake drive.

To increase the reliability of the braking system on many vehicles, the pneumatic booster with the main brake cylinder is installed in two copies. The front actuates the brakes of the front axle, rear, respectively, of the rear axle.

The pneumatic amplifiers are removed from the vehicle and disassembled only for maintenance or troubleshooting.