This article will introduce several points that need to be paid attention to when selecting air pneumatic cylinders:
Classification of air pneumatic cylinders
- From the action is divided into single-action cylinder and double-action cylinder. Single-acting cylinders are divided into spring pressure back and pressure out of two. It is generally used in situations where the stroke is short and the output force and movement speed are not high. Double-acting cylinders are more widely used.
- From the function, there are many types: such as standard cylinder, composite cylinder, special cylinder, swing cylinder, air claw, etc. Which is more commonly used for free installation cylinder, thin cylinder, pen-shaped cylinder, double-rod cylinder, slide cylinder, rodless cylinder, rotary cylinder, gripper cylinder.
Based on the application of the cylinder in the dynamic characteristics or spatial layout, when we actually choose the cylinder, we first determine a suitable category from three aspects: functional requirements, space requirements, and accuracy requirements.
Selection of air pneumatic cylinder type
According to the work requirements and conditions, the correct choice of cylinder type. Require the cylinder to reach the stroke terminal without impact phenomenon and impact noise should be selected buffer cylinder. Require light weight, should choose light cylinder. The installation space is narrow and the stroke is short, and the thin cylinder can be selected. With transverse load, the cylinder with guide rod can be selected.
High braking accuracy is required, and locking cylinders should be selected. The piston rod is not allowed to rotate, and the cylinder with non-rotating rod function can be selected. High temperature environment need to choose heat-resistant cylinder. In a corrosive environment, corrosion resistant cylinders must be selected. In the harsh environment such as dust, it is necessary to install a dust cover at the extended end of the piston rod. When no pollution is required, no oil or no oil lubrication cylinder is required.
According to the installation location, the purpose of use and other factors. In general, fixed cylinders are used.
- When it is necessary to rotate continuously with the working mechanism, the rotary cylinder should be selected.
- When the piston rod is required to move in a straight line and to swing in a circular arc, the shaft pin type cylinder is used.
- When there are special requirements, the corresponding special cylinder should be selected.
The magnitude of the force
That is, the choice of cylinder bore. According to the size of the load force to determine the output of the cylinder thrust and tension. Generally according to the external load theory balance conditions required by the cylinder force, according to different speeds to choose different load rate, so that the cylinder output force to leave a margin. If the cylinder diameter is too small, the output force is not enough, but the cylinder diameter is too large, the equipment is cumbersome, the cost is increased, and the air consumption is increased. In the fixture design, the expansion mechanism should be used as far as possible to reduce the size of the cylinder.
It is related to the stroke of the use occasion and the mechanism, but generally do not choose a full stroke to prevent the piston and the cylinder head from colliding. If used for clamping mechanisms, etc., a margin of 10-20mm should be increased according to the required stroke.