# How To Calculate A Pulley

## Video: How To Calculate A Pulley

Pulleys are used to transfer torque from the engine to other components and assemblies. To calculate the optimal values ​​of the nodes that make up the belt drive, it is necessary to perform some calculations.

## Instructions

### Step 1

Calculate the diameter of the drive pulley by the formula: D1 = (510/610) · ³√ (p1 · w1) (1), where: - p1 - engine power, kW; - w1 - angular velocity of the drive shaft, radians per second. Take the value of engine power from the technical characteristics in its passport. As a rule, the number of engine revolutions per minute is also indicated there.

### Step 2

Convert the number of engine revolutions per minute to radians per second by multiplying the original number by a factor of 0, 1047. Substitute the found numerical values ​​into formula (1) and calculate the diameter of the drive pulley (node).

### Step 3

Calculate the diameter of the driven pulley using the formula: D2 = D1 u (2), where: - u - gear ratio; - D1 - diameter of the drive unit calculated according to formula (1). Determine the gear ratio by dividing the angular to calculate its angular velocity. To do this, calculate the ratio of the diameter of the driven pulley to the diameter of the driving pulley, then divide by this number the value of the angular velocity of the driving unit.

### Step 4

Find the minimum and maximum distance between the axes of both nodes according to the formulas: Аmin = D1 + D2 (3), Аmax = 2,5 (D1 + D2) (4), where: - Аmin - minimum distance between the axes; - Аmax - maximum distance; - D1 and D2 - diameters of the driving and driven pulleys. The distance between the axes of the nodes should not be more than 15 meters.

### Step 5

Calculate the length of the transmission belt using the formula: L = 2A + P / 2 (D1 + D2) + (D2-D1) ² / 4A (5), where: - A is the distance between the axes of the driving and driven nodes, - Π is the number "Pi", - D1 and D2 - the diameters of the driving and driven pulleys. When calculating the length of the belt, add 10-30 cm to the resulting number for its stitching. So, using the above formulas (1-5), you can easily calculate the optimal values ​​of the nodes that make up the flat-belt transmission.