How to choose a planetary gearbox?

Release Time：

2025-03-29

Planetary reducer is a new type of reducer with wide universality. In the reducer family, planetary reducer is widely used in servo, stepper, DC and other transmission systems due to its small size, high transmission efficiency, wide reduction range, and high accuracy. Under the premise of ensuring precision transmission, it is mainly used to reduce speed, increase torque, and reduce the ratio of load/motor moment of inertia.

How to choose a planetary gearbox?
1、 Clarify application scenarios and core requirements
1. Adaptation to industry characteristics
In the field of robotics, high precision (return clearance ≤ 3 arc minutes) and high dynamic response (such as humanoid robot joints requiring torque density>180Nm/kg5) are required. It is recommended to use Harmonic Drive harmonic reducer or Guomao 3K planetary reducer (single-stage reduction ratio 1:20-30, suitable for robot dog hip/knee joints 5).

Industrial automation: focuses on durability and cost balance, and can choose Zhongdalide ZD series (domestic high cost-effectiveness) or SEW-EURODRIVE standard reducer.
CNC machine tools require low backlash (≤ 5 arc minutes) and high rigidity, with the Neugart PLF series (torsional stiffness of 93Nm/arcmin9) or STOBER modular reducers being preferred.

2. Load and motion parameters
Torque calculation: The output torque should be ≥ load torque x safety factor (usually 1.2-1.5). For example, driving a 100kg load at a speed of 0.5m/s requires a torque of ≈ (100 × 9.8 × 0.5)/0.1=4900N · m (assuming a transmission radius of 0.1m).
Speed matching: Determine the transmission ratio based on the motor speed and equipment required speed, formula: i=equipment required speed motor speed.
Inertia ratio: The ratio of motor inertia to load inertia should be ≤ 10, otherwise it may cause motor overload or system oscillation.

2、 Key points for selecting core parameters
1. Transmission ratio
Single stage transmission: reduction ratio range 3:1-10:1, efficiency>97% (such as PLV series single-stage efficiency 98% 11).
Multi stage transmission: Higher reduction ratios are achieved through combination (such as two-stage 10:1-100:1, three-stage>100:1), but the efficiency decreases by about 3% for each additional stage.
Special requirement: Right angle reducers (such as JVF series) can save space, but the transmission efficiency decreases by 5% -10%.

2. Return gap
High precision scenarios: Robots and semiconductor equipment require ≤ 5 arc minutes (such as PLV series return gap<3'11).
Ordinary industry: 8-20 arc minutes is sufficient, and can be optimized by adjusting the gasket or grinding process.

3. Efficiency and heat generation
Diagonal tooth structure: The efficiency is 3% -5% higher than that of straight teeth (such as JXF series helical teeth with an efficiency of 96%), suitable for continuous operation scenarios.
Heat dissipation design: When subjected to high loads, it is necessary to choose models with heat sinks or fans (such as the 30% increase in heat dissipation efficiency of Guomao's synthetic steel reducer).
Planetary reducer is a new type of reducer with wide universality. In the reducer family, planetary reducer is widely used in servo, stepper, DC and other transmission systems due to its small size, high transmission efficiency, wide reduction range, and high accuracy. Under the premise of ensuring precision transmission, it is mainly used to reduce speed, increase torque, and reduce the ratio of load/motor moment of inertia.