1) Description of Internal Spur Gear

In certain specific application scenarios, spur gears become the irreplaceable preferred solution due to their unique technical characteristics, particularly in situations requiring axial positioning or sliding meshing.

2) Working Principle

Its characteristic of ‘zero axial thrust’ offers a significant advantage in mechanisms requiring precise axial positioning. Simultaneously, the profile's unique design renders it exceptionally well-suited for use in sliding gear mechanisms, where axial movement enables the engagement and disengagement of different gear pairs.

3) Characteristics of Internal Spur Gear

• Facilitates axial movement: With tooth surfaces parallel to the axis, it is highly suitable for use as a sliding gear.
• Precise axial positioning: No axial play arises from the transmission mechanism itself.
• Can be fabricated into a rack: By infinitely enlarging the radius of a spur gear, a rack is formed, enabling the conversion between rotary and linear motion.

4) Advantages of Internal Spur Gear

• It is the simplest and most direct gear configuration for achieving gear shifting functionality.
• In precision instruments, it facilitates the maintenance of stable axial dimensional chains.
• It constitutes the sole viable solution for forming a rack-and-pinion gearing system.

5) Application

Primarily employed in mechanisms requiring the utilisation of its unique structural characteristics:

• Synchroniser ring gear in manual automotive transmissions
• Sliding gear sets within machine tool gearboxes
• Rack-and-pinion mechanisms in steering systems
• Counters and transmission mechanisms in precision instruments