(1) Selection of gear parameters
1. Under the premise of satisfying the bending fatigue strength, when the center distance is constant, more teeth should be selected, which can increase the coincidence degree, make the transmission stable, and reduce the noise. On the premise of meeting the transmission requirements, the number of teeth of the large and small gears should be mutually primed to disperse and eliminate the influence of gear manufacturing errors on the transmission. It can also prevent a certain tooth on the large and small gears from meshing with each other periodically to make the transmission smooth Reduce noise.
2. Using a smaller pressure angle can reduce the running noise. Considering the influence of intensity comprehensively, the standard value of 20 is usually taken. When the structure permits, helical gears should be given priority, and its vibration and noise are greatly reduced compared with spur gears. Generally, the helix angle is required to be selected between 8-20.
3. Under the economic capacity that the user can bear, the precision level of the gear should be improved as much as possible when designing. High-precision gears produce much less noise than low-precision gears. In order to reduce the noise of the gear reducer, when the gear backlash is selected, if the transmission is pulsating rotation, a smaller backlash should be selected. If it is a more even and balanced load, a slightly larger tooth backlash should be selected.

(2) Selection of gear structure
1. Under the conditions permitted by the overall structure and design specifications, appropriately increase the tooth width. In this way, the unit load of the gear can be reduced, the deformation of the gear can be reduced, and the transmission noise can be reduced.
2. When designing gears, solid structures should be avoided as much as possible, and web structures should be designed. In the case of meeting the strength, the weight of the gear should be reduced as much as possible. In this way, the natural frequency of the gear can be reduced, thereby reducing the noise of meshing.
3. The optimized design of the cabinet can reduce noise and vibration. Specific noise reduction methods include: using acoustic sound-absorbing materials, using a combined isolation frame, and increasing the rigidity of the box. The main design principle is to ensure that the resonance of the gear reducer box and other supporting parts differs by at least 20% from the rotation speed, the multiple of the rotation speed, and the meshing frequency of the gear teeth.
4. Bearing selection "In order to reduce the noise of the gear reducer, in general design, the type, fit and clearance of rolling bearings should be reasonably selected according to the requirements of use. In high-speed transmission, fluids that run more smoothly than rolling bearings should be used Lubricate the bearings.
 
(2), manufacturing and process
1. Gear modification adopting gear trimming can effectively reduce the impact in gear transmission. Gear trimming includes tooth tip trimming and tooth root digging as well as tooth direction and tooth profile trimming. They can make the convex tooth surface slide smoothly in the meshing and meshing contact without impact, and compensate for the size The smaller parallelism of the gear axis can also improve the noise caused by the transmission error due to the deformation of the gear teeth under load.

2. The control of gear error and tooth surface roughness in the manufacturing process focuses on controlling the tooth profile error, tooth pitch difference, tooth trajectory error and tooth surface roughness during the manufacturing process, so as to obtain the best gear in the process Comprehensive quality can greatly reduce the noise caused by gears.

3. The dynamic unbalance of the rotating part" The unbalance of the rotating body should be controlled within less than 6.6kg/(r/min). (4) Control of box center distance and bearing hole shape tolerance" Control box center distance With the tolerance of the bearing hole shape and position, it can reduce the noise generated by gear meshing.