The module of a gear is an important parameter indicating the size of the gear teeth and is usually measured by the following methods:
Measuring with a Gear Measuring Instrument
• Using a Gear Measuring Machine: Professional gear measuring machines can accurately measure various parameters of gears, including the module. The gear is fixed on the measuring machine, and through precision sensors and measurement systems, the machine can directly obtain data such as the tooth profile, pitch, and helix angle of the gear. By analyzing these data, the module of the gear can be calculated. This method is highly accurate and suitable for measuring gears with high precision requirements, but the equipment is expensive and requires professional operation.
• Using a Gear Tooth Vernier Caliper: A gear tooth vernier caliper can measure the chordal thickness and chordal addendum of the gear teeth. For a standard gear, there is a certain relationship between the module, chordal thickness, and chordal addendum. By measuring the chordal thickness and chordal addendum of the gear teeth and referring to the relevant gear parameter calculation formula, the module of the gear can be calculated. The accuracy of this method is relatively high and is suitable for on-site measurement of general precision gears.
Calculation Based on Known Parameters
• Calculation from the Number of Teeth and Pitch Circle Diameter: If the number of teeth and the pitch circle diameter of the gear are known, the module can be calculated using the formula . The pitch circle diameter can be measured with a measuring tool such as a vernier caliper or micrometer. When measuring, it is necessary to measure the diameter of the gear at the position of the pitch circle as accurately as possible.
• Calculation from the Center Distance and Transmission Ratio: In a gear transmission system, if the center distance between the two gears and the transmission ratio are known, and the number of teeth and of the two gears satisfy the relationship , and the center distance . By combining these equations, the module can be calculated.
Comparison with a Standard Gear
• Visual Comparison: Select a standard gear with a known module and compare it with the gear to be measured. By observing the size of the gear teeth and making a rough comparison, an approximate value of the module of the gear to be measured can be estimated. This method is simple and quick but has low accuracy and is only suitable for rough judgment.
• Overlay Comparison: Place the standard gear and the gear to be measured together and observe the degree of coincidence of the tooth profiles by overlaying them. If possible, you can also use a projector to project the tooth profiles of the two gears onto a screen for comparison. By adjusting the position and angle, find the standard gear that best matches the gear to be measured, and the module of the standard gear is the approximate module of the gear to be measured.
Post time: Mar-08-2025