The two main factors that measure the performance of gears are: load capacity and fatigue life, often ignoring the transmission noise and transmission accuracy. With the ISO14000, ISO18000 two successive promulgation, control gear transmission noise this factor is becoming increasingly important, industrial development and demand for high precision equipment transmission error requirements are more stringent (gear drive backlash). Currently known gear noise formation factors, can be from the design, manufacture, installation, maintenance and other aspects of the analysis.
1. Gear accuracy level
Gear drive system design, the designers are often from the economic considerations, as far as possible to determine the economic accuracy of the gear level, not knowing the accuracy level is the gear noise level and backlash mark. The gear manufacturing association has adopted a large number of gear studies to determine the high-precision grade gears than the low-precision level gears produce less noise. Therefore, in the case of conditions permit, as far as possible to improve the accuracy of the gear level, to reduce the gear noise, reduce transmission error.
2. Gear width
When the gear drive system allows, increase the tooth width and reduce the unit load at constant torque. Reduce gear deflection, reduce noise excitation, thereby reducing the transmission noise. Germany H Opats study shows that the torque is constant, the small tooth width than the large tooth width noise curve gradient high. While increasing the tooth width can increase the load capacity of the gear.
3. Pitch and pressure angle
Small pitch to ensure that more teeth at the same time contact, gear overlap increased, reducing a single gear deflection, reduce transmission noise, improve transmission accuracy. The smaller pressure angle is relatively large due to the gear contact angle and the lateral overlap ratio, so the running noise is small and the precision is high.
4. Operation speed
According to the German Hopaz test study shows that with the gear speed increases, the noise level increases.
5. Gearbox structure
Experimental results show that the use of cylindrical box on the shock absorption, in other conditions are the same circumstances, the general structure of the gear box noise level than the average height of the cylindrical box 6dB higher. Resonance testing of gearboxes, finding the resonant position, increasing the appropriate ribs (plates), can significantly reduce vibration and reduce noise. Multi-stage gear transmission requires instantaneous transmission ratio changes as small as possible, has guaranteed smooth transmission, shock and vibration, low noise.
6. Analysis of gear acoustic radiation characteristics
In the selection of different forms of gear, the specific structure of its acoustic radiation model, the dynamic analysis of the gear transmission system noise in advance to assess. In order to meet the different requirements of the user (the use of places, whether or not to operate, whether in the city, on the ground, underground buildings with specific requirements, whether there is noise protection, or no other specific requirements) to meet.