A DC motor running at high speed requires a device to reduce speed and increase torque. The gear reducer is the power transmission device to realize this process. You can read our previous article on

What's The Difference Between Spur Gears And Helical Gears? to know the classification of reducer. In this article we mainly to learn about planetary gearbox.

Three important definitions:

Stage number: The number of planetary gears. Because a set of planetary gears can not meet the large transmission ratio. Sometimes two or three sets are needed to meet the requirements of a large transmission ratio. Since the number of planetary gears is increased, the length of stage 2 or 3 reducer will be increased, and its efficiency will be decreased.

Return clearance: When the output end is fixed and the input end is rotated clockwise and counterclockwise, so that the input end produces rated torque +-2% torque, there will be a small angular displacement at the input end of the reducer. This angular displacement is the return clearance. The unit is "minute", which is one sixtieth of a degree, also known as the backgap.

Planetary gearbox structure:

Planetary gearbox structure: planet gear, sun gear, outer gearring.

Planetary reducer is simple in structure. The minimum single-stage deceleration is 3, and the maximum is generally no more than 10. Common deceleration ratio is: 3, 4, 5, 6, 8, 10, reducer series generally does not exceed 3, but some large deceleration ratio customized reducer has 4 levels of deceleration.

How To Choose A Planetary Gearbox?

First, please determine the type of planetary gearbox. Is there an axis or without axis? Is it a planetary wheel or helical gear, etc. Then we can make the following choices.

Step 2: The power required by your device.

Step 3: Gear ratio

Gear ratio is the ratio of input speed and output speed of reducing planetary reducer, and the formula is input speed/output speed = deceleration ratio of planetary reducer.

Step 3: Determine the torque.

When the power and speed are determined, the torque of reducer can be obtained by the formula.

Gearbox torque =9550× motor power ÷ motor power input revolution × speed ratio × usage coefficient

Step 4: Determine the deceleration installation method. Such as: flange installation, shaft output, etc.

Notes:

Choose the planetary reducer, need to carry out detailed calculation, it is best to have a professional technical personnel to calculate. Or Speak to our sales engineers for technical support.