Transmission worm gear: A core component for precise power transmission
Classification： Blog
Release time：2025-06-25
Transmission worm gear: A core component for precise power transmission
Definition and Function:
A transmission worm gear is a shaft-type component with a special helical tooth profile. It meshes with a worm wheel to form a worm gear pair, used for power and motion transmission between intersecting shafts (usually 90°). Its core value lies in achieving 。其核心价值在于实现 high reduction ratios, self-locking, and compact structure , with a single-stage transmission ratio reaching 5:1 to 100:1 or more.
Core Characteristics:
High Reduction Ratio : A single rotation of the worm gear only pushes a few teeth of the worm wheel, significantly reducing speed and increasing torque.
Self-locking Capability : When the worm lead angle is less than the friction angle, the transmission is irreversible (the worm wheel cannot drive the worm), providing inherent safety.
Compact Structure : Smaller volume than gearboxes at the same reduction ratio.
Smooth and Low-noise Transmission : Continuous line contact meshing, resulting in low vibration.
Efficiency Bottleneck : Sliding friction leads to lower efficiency (40%-90%), often below 50% in self-locking conditions, requiring attention to heat dissipation design.
Key Design Elements:
Tooth Profile : Commonly used are Archimedes worm gears (ZA), involute worm gears (ZI), and circular cylindrical worm gears (ZC), affecting contact stress and efficiency.
Material Pairing ：
Worm Gear : Quenched steel (20CrMnTi carburizing and quenching, 45 steel high-frequency quenching), hardness ≥45HRC.
Worm Wheel : Friction-reducing materials (tin bronze ZCuSn10P1, aluminum bronze ZCuAl10Fe3).
Accuracy Grade : ISO 1328 standard, precision transmission requires grade 6 or higher accuracy.
Lubrication and Cooling : Forced oil bath lubrication or circulating oil spray; high-temperature conditions require additional heat dissipation fins or coolers.
Manufacturing Process Key Points:
Turning/Milling : Rough machining of the helical groove.
Heat Treatment : Tooth hardening treatment ensures wear resistance.
Grinding : Precision worm gear grinder finishing, surface roughness Ra ≤0.4μm, lead error ≤0.005mm.
Inspection : Three-coordinate measurement of tooth profile/tooth direction error, lead screw gauge verification of motion accuracy.
Typical Application Scenarios:
Safety Braking : Elevator traction machines, crane winches (using self-locking to prevent falling)
Precision Indexing : CNC turntables, machine tool indexing heads
Heavy-load Speed Regulation : Mine conveyors, valve drive devices
Space-constrained Transmission : Medical devices, automated robotic arm joints
Technology Trends:
Tooth Profile Optimization : Using ZC type worm gears and planar secondary enveloped torus worm gears to increase load-carrying capacity by more than 30%.
Surface Engineering : Nitriding, DLC coating reduces the friction coefficient.
Integrated Design : Direct drive integration with servo motors reduces transmission chain errors.
Conclusion:
Transmission worm gears, with their high reduction ratios and self-locking characteristics, are irreplaceable and serve as the "force and control" hub in mechanical systems. Through material innovation, precision manufacturing, and lubrication optimization, their efficiency and lifespan continue to improve, continuously playing a core value in high-end equipment fields.
keyword：