Strength design of screws? What is the formula for calculating a screw?

1. Screw stress:

1) Self-weight g;

2) the torque required to overcome the resistance of the material m ;

3) Axial force p generated by the pressure of the material.

The screw is generally scrapped due to long-term wear and tear, and the gap between the screw and the barrel is too large to be extruded normally, but there are also examples of damage due to improper design or operation when the working stress exceeds the strength limit. Therefore, the screw should also meet certain strength requirements.

4) The dangerous section of the screw is generally at the smallest thread diameter in the feeding section.

According to the mechanics of materials, for plastic materials, the composite stress is calculated by the third strength theory, and its strength conditions are:

2. Strength calculation.

3. Other circumstances:

1) For the situation that the tail of the screw is connected with the main shaft of the reducer in a floating connection, because the screw floats in the barrel, the bending stress caused by the self-weight of the screw is equal to zero, so it is only calculated according to the compressive stress and shear stress of the screw.

2) Since the bending stress caused by the weight of the screw is very small (the screw is surrounded by material), even in the former case, it can be omitted, so the two methods are practically the same.

3) There are also pure torsion to estimate the screw diameter.

There are two kinds of ordinary bolt connections and hinged bolt connections

Normal: 1. The bolt preload f=4te (d+d1)n required to meet the torque transmission is f=4te (d+d1)n unit: N.

2. Strength condition of bolt connection: = unit: n mm2 hinging:

1. The shear force of each bolt fa=2te d0n n2, the bolt shear strength condition = 4fe ( d0 2) "[n mm23, the extrusion strength condition of the bolt connection p=fe (d0h)"[p] n mm2

The size chart is as follows:

Calculation of bolt tensile strength.

Bearing capacity Strength x Area;

The bolt is threaded, and the cross-sectional area of the M24 bolt is not a circular area of 24 diameters, but 353 square millimeters, which is called the effective area.

The tensile strength of ordinary bolt grade C (and grade) is 170n square millimeters.

Then the bearing capacity is: 170x353 60010N.

There are two ways to quickly calculate:

The most tension screw is the wall, first of all, how to calculate the wall first.

Method 1: You can use the formwork of the wall, the total amount of formwork divided by 2 and then divided by the spacing of the tie screws, but this does not take into account when the wall is turned.

angles, walls less than 600 are not set with tie screws, so they are not very accurate. Method 2: Can be utilized, steel.

To calculate the tension reinforcement in the reinforcement shear wall, firstly, replace the wall column with the wall, then delete the wall that does not meet the spacing of the tension screw, and then change the tension spacing to the spacing of the tension screw in the property of the reinforced rock fiber wall. Calculate, count the number of roots.

The calculation formula is set in the excel sheet, and the number of roots is automatically counted. 2. Use the reinforcement column to stretch the bar, set the spacing, layer height, and then calculate, system.

Number of roots. 3. Beam: 1. Go to the tree table in the civil engineering report, find the beam template, and select the handsome to meet the setting pair.

Pull screw beam, do not meet the deletion, divide the length in the template by the spacing of the tension screw, meet the setting of two and then multiply by a few. 2. Or profit.

With steel bars, there are tension bars in the beam waist reinforcement, and when statistical, go to the steel bar beam ** method first to check and meet.

Count the tension ribs, that is, the tension screw.