The Difference Between Helical z12191 Gears and Spur z12191 Gears

1. Transmission Principle

• Spur Gears: The tooth profile of spur gears is distributed along the gear's axis. During transmission, the meshing of the two gear teeth occurs simultaneously across the entire tooth width. That is, when a pair of spur gears begins meshing, the entire tooth width of both gears enters contact simultaneously; when meshing ends, the entire tooth width disengages simultaneously.

• Helical Gears: The tooth profile of helical gears is inclined relative to the gear axis. During transmission, tooth engagement occurs progressively: it begins at one end of a tooth, gradually transitions to involve the entire tooth width, and finally disengages progressively from the other end.

2. Structural Characteristics

Spur Gears

• Simple Profile: Straight gears feature relatively simple tooth profiles and structures. Their tooth lines are parallel to the axis, enabling straightforward machining processes. They are easy to manufacture and can be produced using standard mechanical processing equipment.

• No Axial Forces: Since the tooth surfaces of straight gears are perpendicular to the axis, no axial forces are generated during transmission. This reduces requirements for axial positioning and support, simplifying shaft and bearing design and installation.

Helical Gears

• Complex tooth profile: Helical gears feature spiral tooth surfaces, resulting in a more intricate tooth profile than spur gears. Manufacturing requires specialized tools and machinery, such as gear hobbing machines and gear shaping machines, with higher demands on machine setup and operator skill.

• Axial Force Presence: Helical gears generate axial forces during transmission. These forces act on the gear shaft and bearings, necessitating countermeasures to balance them. Solutions include using double helical gears (combining two helical gears in opposite directions) or employing bearings capable of handling axial loads, such as tapered roller bearings.

3. Performance Characteristics

Smoothness of Transmission

• Spur Gears: Spur gears engage and disengage instantaneously, causing significant impact and noise during transmission. This impact and noise become more pronounced at high speeds, resulting in poor transmission smoothness.

• Helical Gears: The teeth of helical gears engage and disengage gradually, resulting in reduced impact and vibration during transmission. This provides smoother operation with relatively lower noise levels, making them particularly suitable for high-speed, heavy-load applications.

Load Capacity

• Spur gears: Teeth engage and disengage simultaneously, with fewer tooth pairs involved in each engagement. This results in higher load per unit area, leading to relatively lower load capacity.

• Helical Gears: Teeth engage gradually, with more tooth pairs involved simultaneously than in straight gears. This distributes the load, reducing the load per unit area and enhancing the gear's load capacity, enabling transmission of greater torque.

Fork Ratio

• Spur gears: Spur gears have a low fork ratio, typically between 1 and 2. This means fewer tooth pairs engage simultaneously during transmission, limiting the continuity and smoothness of power transfer.

• Helical Gears: Helical gears have a higher overlap ratio, generally greater than 2. This ensures multiple tooth pairs are always engaged simultaneously during transmission, enhancing continuity and smoothness while improving load capacity and wear resistance.

4. Application Scenarios

Spur Gears

• Low-speed, light-load applications: Due to their simple structure and low manufacturing cost, spur gears are commonly used in scenarios with low requirements for transmission smoothness and noise, such as simple mechanical transmission devices and hand tools.

• Cost-Sensitive Applications: In cost-sensitive scenarios like low-end machinery and toys, spur gears gain widespread adoption due to their straightforward manufacturing processes and affordability.

Helical Gears

• High-Speed, Heavy-Load Applications: Helical gears deliver smooth transmission and high load capacity, making them ideal for high-speed, heavy-load scenarios like automotive, aerospace, and marine transmission systems, ensuring efficient and reliable operation.

• Applications with high noise and vibration requirements: In scenarios demanding low noise and vibration, such as precision machine tools and elevators, helical gears deliver smoother transmission, reduce noise and vibration, and enhance equipment operational quality and precision.