Core concept: 

 Electric actuator: The power source that provides rotational or linear motion. 

 Secondary transmission gearbox: Refers to a gearbox that contains a two-stage worm and gear reduction mechanism. 

 Worm and gear drive: Utilizes a worm (similar to a screw) to drive a gear (similar to an oblique gear) to achieve a large reduction ratio and a change in the direction of motion (usually 90 degrees). 

 Secondary transmission: Indicates that there are two sets of such worm and gear pairs working in series to achieve a larger overall reduction ratio.

2. Core calculation formula

3.detailed explanation of the second-level transmission loss ratio

Loss distribution (actual data)

Total efficiency η_total = η1 × η2 × η bearing × η seal 

 Efficiency of new machine: .45~0.55 (precision ground worm shaft   tin bronze worm wheel) 

 Efficiency after aging: ↓0.25~0.35after 3 years of operation, lubrication deterioration   tooth surface wear) 

 Warning: The calculated torque must be selected according to η_total = 0.30.4, otherwise it may not be able to carry the load!

 4. Notes for selection (avoid pit guide)

（1）Drive train selection

（2） Material and Process Requirements 

 Gear: 20CrMnTi carburizing and quenching (hardness HRC8-62), surface roughness Ra ≤ 0.8μm

 Gear: ZCuSn10P1 centrifugal casting, no substitution cast aluminum allowed! 

 Lubricating Grease: Polyurea synthetic grease (operating temperature -30~180℃), fill amount ≤50% of housing volume (excessive amount exacerbates oil agitation) 

 （3） Heat Management Measures

 Housing surface area: Calculate heat dissipation as_loss = (1-η_total) × P_in 

 Forced cooling requirements: 

 P_in > 15kW \quad \Rightarrow \ \text{Add heat fins} \\

 P_in > 30kW \quad \Rightarrow \quad \text{Forced air cooling (fan power  5% P_in)} 

 （4） Self-locking Reliability Verification 

 Self-locking condition: Helix angle of the gear γ <ctan(μ) (μ ≈ 0.05~0.12) 

 Test requirements: Maintain pressure for 10 minutes at 1. times T_required, with displacement ≤ 0.5°

 4.Cost Optimization Strategies 

（1） Comparison of alternative solutions

（2）Cost-saving tips

Non-critical valve: use bevel gear   single worm (η_total≈0.5, cost ↓30%);

Medium light load valves: use nylon worm wheel for output stage (load ↓40%, but cost ↓50%).

5. Fault early warning indicators

6.Computational examples in engineering applications