Basic concept and selection calculation of reducer

Writer：tilireducer Time：2026-10-29 09:54:43 Browse：1℃

Ⅰ. What is a reducer?

In simpler terms, a reducer is a "speed reducer and force amplifier".

Just like a car shifting gears to ascend a slope, a reducer can convert the high-speed rotation of a motor into low-speed high-torque output. For example, if a motor rotates 1,500 times per minute, after being "processed" by the reducer, the output end may only rotate 30 times, but the force can lift hundreds of pounds of heavy objects!

II. Composition of the Reducer Now that we have understood what a reducer is, let's take a closer look at its components. It primarily consists of three main parts: 1. Gear set: Similar to a bicycle gearbox, gears of different sizes mesh together to change the rotational speed.

2. Bearing: A precision component that ensures smoother rotation.

3. Box body: Generally made of metal, it serves to protect the internal components.

III. Four common types of reducers: Types Advantages Disadvantages Application Scenarios Gear reducer Durable, affordable Slightly noisy Conveyor belts, mixers, etc. Planetary reducer High precision, compact structure Complex structure Robotic arms, machine tools, etc. Worm gear reducer Self-locking, safe, high speed ratio Low efficiency Cranes, elevators, etc. Harmonic reducer Zero backlash, long lifespan Maintenance is troublesome Mining machinery, etc

IV. Five-step method for reducer selection 1. Assess load usage Smooth loads: such as conveyor belts, fans, etc. Shock loads: such as punch presses, crushers, etc. 2. Calculate load torque formula Required torque T = 9550 × motor power (kW) ÷ output speed (r/min) Example: A 0.75 kW motor needs to output 30 r/min

Torque T = 9550×0.75÷30 ≈ 239N·m

3. Determine the reduction ratio

Speed ratio i = motor speed (input speed) ÷ required output speed (output speed)

(Common speed ratio is 5-100, and special models can reach 10000:1)

4. Check the power meter

Refer to the manufacturer's parameter table and select a model with a load capacity equal to or greater than the calculated value, leaving a safety margin: torque × 1.2~1.5 times

5. Measure the installation dimensions

Confirm whether the flange type (flange type, shaft-mounted type), installation dimensions, and shaft diameter match the equipment

V. Practical case scenario: Selecting a reducer for a mixer. The motor power is 5.5 kW, with a rotational speed of 1440 r/min. The required rotational speed of the mixing shaft is 60 r/min, and the load torque is 800 N·m.

1. Reduction ratio i=1440/60=24 → Choose standard value 25

2. Theoretical output torque = 9550 × 5.5 / 60 ≈ 880 N·m

3. Actual torque demand: 800×1.5=1200N·m

4. Select a gear reducer (with an efficiency of 95%) with a model rated torque of ≥1200N·m

VI. Pitfall Avoidance Guide Environmental Factors: For high-temperature environments, choose heat-resistant oil seals. For humid conditions, opt for waterproof models. For dusty environments, use fully sealed structures. Maintenance Tips: It's a little-known fact that the oil must be changed after the first 200 hours of operation!

Choosing the wrong type of oil = wasted maintenance