Here, metal wire is selected to weave the screen surface. The screen hole size is 8mm, the diameter of light steel wire d is 2mm, the opening rate is 64%, and the length width ratio is 3:1.

Calculation of handling capacity of circular vibrating screen:

Approximate calculation by formula [7]: (4-1)

Where: – processing capacity calculated by feeding (t/h);

M — Correction coefficient of screening efficiency, see Table 4-10 [7]; M can also be calculated according to the following formula:

**M＝**

**——Screening efficiency;**

**——Volume treatment capacity per unit area (/· h), see Table 4-11 [7];**

**——Calculated width of screen surface (m);**

**＝0.95B；**

B — actual screen width (m);

L – working length of screen surface (m);

——The loose density of the material (t/).

According to Table 4-10 [7] and Table 4-11 [7], when the screening efficiency is 98%, M is 0.27, 1.1, 13.30/· h, Q=0.5T/h. According to the actual requirements, the length of the screen surface is taken as three times of the width, that is, L=2B,=0.95B, then:

So B=

The width of screen surface is 330mm, the length is 660mm, and the inclination angle of screen surface is 20 °.

Selection and calculation of motor

**P= (4-2)**

**Where, P – calculated power of motor (KW);**

**——Vibration mass (kg);**

**——Amplitude (m);**

**N – vibration frequency (r/min);**

**D – bearing times (m);**

**C — damping coefficient, generally C=0.2;**

**F – bearing friction coefficient, f=0.005 for rolling bearing;**

**——Transmission efficiency, take=0.95.**

According to practical experience, amplitude is generally selected according to the following range:

Circular vibrating screen=2.5~4mm

Here we take any value=3mm, n=600r/min, P=5kw, d=50mm;

Try to find=

It is calculated that the vibration mass is too large, which will inevitably increase the manufacturing cost. Therefore, it is not used. Now, P is taken as 0.5kw, and it is calculated as 1500.9kg, which is more suitable. Check the Mechanical Design Course Design Manual (Table 12-1) [1]

The motor Y801-4 is selected, the power P is 0.55kw, the speed is 1390r/min, and the mass m=17kg.

The general calculation formula of equivalent dynamic load P () is

P=X (4-3)

Where, X and Y are the radial dynamic load coefficient and axial dynamic load coefficient respectively. See Table 13-5 in Reference [2] for their values. As shown in the table: X=1, Y=0;

P=1.2, so: P=1.2=17.65kw

Calculation of rolling bearing life:

Basic rated life of bearing (4-4)

**N represents the rotational speed of the bearing (unit: r/min), which is an index. For ball bearings,=3, and for roller bearings,=. According to the mechanical course design manual, C=69.2KN.**

**=2639.8h**

The calculated life meets the design requirements, so the bearing inner diameter d is taken as 50mm. After checking the mechanical course design manual, it can be concluded that D=90mm, B=20mm.

1.2 Life calculation of bearing

The life formula of the bearing is:

=() (6-4)

Where: unit of is 10r

——Is an index. =3 for ball bearings; =10/3 for roller bearings.