How to Calculate Gear Tooth Width?

[LaRhett]

Gear tooth width is usually expressed by the tooth width coefficient. The coefficient for helical gears is 0.4, for herringbone gears it ranges from 0.5 to 1.0, for straight bevel gears the tooth width = gear coefficient * outer cone distance; for worm gears, the tooth width = 0.65 * worm pitch diameter. Generally, the larger the tooth width coefficient, the wider the gear, and the greater the load-bearing capacity of the gear, but the uneven distribution of load along the tooth direction also increases. Below is relevant information about gears: 1. Classification: Gears can be classified by tooth profile, gear shape, tooth line shape, the surface where the teeth are located, and manufacturing method. The tooth profile of a gear includes the tooth curve, pressure angle, tooth height, and modification angle. 2. Tooth Width: Tooth width refers to the axial length of the gear tooth's entity, i.e., the 'thickness' of the gear.

[PeytonLee]

When calculating gear tooth width, I usually multiply the tooth width coefficient by the module in practice. During projects, such parameters must be determined based on specific application scenarios, like the vastly different load characteristics between automotive transmissions and construction machinery gearboxes. For heavy-duty applications, a larger coefficient is chosen, while lighter equipment can use a smaller one, typically ranging between 10 and 40. During design, theoretical values alone are insufficient—assembly tolerances and spatial constraints must be considered. Otherwise, excessive tooth width can lead to noise or even tooth breakage. Once, during a test by our team, increasing the tooth width by 10% reduced vibration noise by two decibels and significantly extended lifespan. I recommend beginners simulate stress distribution with software before finalizing designs to avoid rework later.

[JuniperRose]

I worked on this calculation when studying mechanical design in university. The core is to calculate based on load-bearing capacity and spatial constraints. The formula is usually gear width equals module multiplied by a coefficient, but the coefficient must comprehensively consider material strength, transmission torque, and safety factor. The textbook mentioned two key points: the transmitted torque determines the minimum strength requirement, while structural space is the upper limit. When designing gear wheels for robot joints, I found through actual testing that a gear width error exceeding 0.5mm would cause a 15% plunge in transmission efficiency. Nowadays, it's quite convenient to optimize gear width parameters using 3D modeling software, and the exported data can automatically generate tolerance analysis reports to avoid issues during physical assembly.

[VanNicole]

In transmission repair cases, I often rely on empirical formulas for gear width calculations. For regular passenger cars, gear width can be 8 to 12 times the module value, while modified race cars can go up to 15 times. Once, a customer installed a high-power engine without adjusting gear width, resulting in tooth breakage after just 300 kilometers. Repair shops usually keep gear width reference charts - just match the torque range to determine the appropriate width. When data is unavailable, measuring the old part's thickness and adding 2mm is generally safe. Remember not to force gears into insufficient space - switching to helical gears may save space if clearance is tight.