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
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