Worm Gear Set (Bronze Worm Gear)

As core components for precision power transmission, metal gears transmit torque and regulate rotational speed through tooth-surface meshing. They are widely used in sectors such as automotive, robotics, industrial automation, home appliances, and medical devices.

Compared to plastic gears, metal gears offer distinct advantages—including high strength, high torque capacity, high-temperature resistance, fatigue/wear resistance, and a long service life—enabling them to withstand demanding conditions like heavy loads; however, they are heavier and more costly than plastic gears.

They are categorized by structure into types such as cylindrical gears, bevel gears, and worm gear sets: Spur gears feature a simple structure and are typically used for standard, low-speed transmission; helical gears offer smooth meshing, low noise, and high load-bearing capacity, making them the mainstream choice for automotive steering and new energy vehicle transmissions; bevel gears enable multi-angle directional changes and are commonly used in robotic joint mechanisms; worm gear sets allow for high reduction ratios and possess self-locking characteristics, frequently serving in actuators and torque feedback mechanisms.

Various gear types are combined to form gearbox reduction mechanisms that achieve functions such as speed reduction with increased torque, power redirection, and position locking; they are indispensable components in the power systems of high-end equipment.

1. Cylindrical Gears (Spur / Helical)

Cylindrical gears include spur gears and helical gears; their axes are parallel to each other.

1) Spur gears are simple to manufacture and low-cost; however, they are prone to vibration and noise at high speeds, so they are mostly used for low-speed, light-to-medium load applications.

2) Helical gears offer smooth meshing and high load-bearing capacity; suitable for high-speed, heavy-load applications, they are the most widely used type.

Cylindrical gear pairs offer high transmission efficiency (97%–99%); a single stage typically provides a ratio of up to 1:5, while multi-stage configurations can achieve very high ratios; input and output axes are parallel.

2. Bevel Gears

These feature intersecting axes—commonly at a 90° right angle—and are categorized into straight bevel gears and spiral bevel gears. 1) Straight-tooth bevel gears: Low speed, high noise;

2) Spiral bevel gears: Smooth meshing, suitable for high speeds and heavy loads.

Changes axis direction (90° turn); single-stage gear ratio of 1:5; efficiency of 95–98%; not suitable for very high reduction ratios.

3. Worm gear sets

The worm is typically the driving component and the worm wheel the driven component; achieves high gear ratios, compact structure, and self-locking capability.

Cylindrical gears, bevel gears, and worm gear sets are assembled into speed reducers to reduce rotational speed, amplify torque, and change input/output shaft directions. By integrating various gear pairs (cylindrical, bevel, worm) into different reduction mechanisms and combining gears in series, specific requirements—such as high gear ratios, single or multiple directional changes, high efficiency, self-locking, and compact size—can be met.

Cylindrical spur gears

• Advantages: Simple structure, easy to manufacture, low cost, high transmission efficiency

• Applications: Standard home appliances, low-speed general-purpose transmissions

Cylindrical helical gears

• Advantages: Multi-tooth meshing, smooth transmission, low noise, high torque capacity, suitable for high-speed operation

• Applications: Automotive EPS/Steer-by-Wire (SbW), new energy vehicle electric drives, robot gearboxes

Bevel gears

• Advantages: Enables 90° directional transmission, compact structure, high load capacity

• Applications: Robot joints, steering transmission mechanisms

Worm gears (bronze worm wheel)

• Advantages: High single-stage reduction ratio, compact size, self-locking capability, smooth operation

• Applications: Steering torque feedback components, gimbal heads, valve actuators

General characteristics of metal gears

✅ Advantages: High strength, high torque resistance, high-temperature resistance, long service life; meets automotive functional safety standards

1. Automotive industry (highest volume)

• Steering systems: EPS (Electric Power Steering), SbW (Steer-by-Wire); helical gears, worm gears, and bevel gears used for torque transmission and angle feedback. • Seat adjustment mechanisms, window lift motors, brake actuators, electronic parking brakes; small metal gears used in motor reduction assemblies.

• Electric drive reduction gears for new energy vehicles (high-power helical gears).

2. Industrial Automation & Robotics

• Joint reduction gearboxes for collaborative robots and quadruped robots (e.g., Deep Robotics): bevel gears, helical gears, and worm gear sets; used for torque amplification and directional transmission.

• Servo motors, planetary gearboxes, conveyor systems, and automated tooling equipment.

3. Home Appliances & Personal Care Devices

• Internal reduction gear sets for robot vacuums and pool cleaning robots (e.g., Xingmai);

• Small metal gears for blenders, high-speed food processors, curling irons, and power tools; designed to withstand high torque.

4. Aerospace/Security/Actuators

• Various actuators: valve drives, security camera gimbals, and camera zoom mechanisms; worm gear sets offer self-locking capabilities, preventing backlash or movement upon power loss.

5. Medical Devices

• Micro-transmission mechanisms for rehabilitation equipment and medical devices; metal gears offer wear resistance, long service life, and high precision.

Application Focus by Gear Type

1. Spur gears: Low-cost, low-speed applications (home appliances, standard small equipment); high noise levels; rarely used in high-end automotive steering systems.

2. Helical gears: Preferred for automotive steering and robotics; offer smooth transmission, low noise, and high load-bearing capacity.

3. Bevel gears: Used when a 90-degree change in direction is required; applications include robot joints and steering mechanisms.

4. Worm gear sets (gold-colored bronze worm gears): Used when high reduction ratios and self-locking capabilities are required; applications include automotive steering feedback mechanisms, gimbals, valves, and robot joints.

Comparison with plastic gears: Metal gears offer advantages such as temperature resistance, high strength, and high torque capacity.