# How to calculate the deflection of air compressor piston

If it is required to obtain the deflection value of the air compressor wire at any point between its two fulcrums, it can be obtained by the following two methods:

(1) Graphic method: on the grid coordinate paper, take the horizontal coordinate as the horizontal distance between the two fulcrums of the steel wire, and the vertical coordinate as the deflection value of the steel wire, and mark it on the coordinate paper in proportion according to the deflection value every 0.5m in the table.

Then, use the curve ruler to connect the marked points into a continuous and smooth curve. From the horizontal distance, the deflection value at any point between the two fulcrums can be obtained from the curve.

That is: according to the ratio of vertical and horizontal coordinates, the number of divisions on the coordinate paper can be calculated, and then converted to size.

(2) Insert calculation method: according to the table of deflection values, the deflection value of any point can be obtained by using insert calculation method.

That is, a small segment of the vertical deflection curve is regarded as a diagonal line, and then the middle value is calculated according to the proportion.

Although this method has errors, it is accurate enough in practice. Because the error value is only about 0.005 mm.

After determining the deflection value of the steel wire at each alignment point, use a complete set of internal micrometer (i.e. micrometer) with a measurement accuracy of 0.01mm to conduct alignment and centering measurement or adjust the length of the micrometer with the help of earphones. That is to say, the so-called "acoustic electric method" alignment and centering system is equipped with batteries, earphones and all lines.

The technical specifications of each part are as follows,

Battery - dry cell for telephone 1.5V;

Earphone - resistance 2000 ohms;

Line - ordinary plastic covered flexible wire.

When one end of the internal micrometer contacts the metal slide or cylinder and the other end touches the wire, the whole system forms a current circuit.

According to the sound intensity of earphones, the accuracy of 0.005 mm (i.e. half channel size) can be generally determined. Adjust the length of the micrometer to get an accurate reading.

Finally, the alignment and centering are divided into the following two steps:

(1) First, align and center the steel wire according to the measuring point position of the slide way of the fuselage (middle body).

When testing with an internal micrometer, adjust the wire frame, move the wire properly, and make it the center line of the slide.

The horizontal distance between the two side points at the front and rear ends of the slideway and the steel wire shall be exactly the same (due to no deflection).

The vertical distance between the steel wire and the top and bottom measuring points of the slide is not equal due to the existence of deflection.

The difference between the readings of the two dimensions (referred to as the upper dimension "a" and the lower dimension "B") measured shall be equal to twice the vertical deflection value of the wire at this point (according to the vertical deflection value of the geometric center line).

(2) Align and center the cylinder according to the steel wire. Put the cylinder on the body or middle body, put on the steel wire, and align and center it according to the body.

Each section of cylinder shall have front and rear alignment measuring points. If it is found that the timing is not correct, adjust the moving cylinder to align it with the fuselage.

If deviation is found during alignment and centering of cylinder, the treatment method is as follows:

The stop plane is corrected by machining so that it can be aligned with the fuselage.

It is not allowed to add partial gasket between the connecting flange ends of the cylinder, or adjust the deviation by loosening and tightening the connecting bolts.