The gear accuracy is mainly to control the accuracy of the transmission between the gears during the operation of the gears, such as: the stability of the transmission, the fluctuation of the instantaneous speed, if there is an alternating reverse operation, whether the backlash of the teeth is minimized, if there is an impact load , should improve accuracy slightly, thereby reducing damage to gears brought by shock loads.
If the above design requirements are relatively high, the gear precision should be set a little higher, otherwise it can be set a little lower. However, if the gear precision is set too high, the processing cost will increase, and a comprehensive balance is required
The above parameters basically belong to the more commonly used gears, and the precision of gear processing can be set as: 7FL, or 7-6-6GM
Explanation of the precision label:
7FL: The accuracy of the three tolerance groups of the gear is 7 grades, the upper deviation of the tooth thickness is F grade, and the lower deviation of the tooth thickness is L grade
7-6-6GM: The tolerance zone precision of the first group of gears is grade 7, the tolerance zone precision of the second group of gears is grade 6, the tolerance zone precision of the third group of gears is grade 6, and the upper deviation of tooth thickness is grade G , the lower deviation of tooth thickness is M grade
There is no calculation formula for gear accuracy, because it does not need to be calculated, it is obtained by consulting the manual.
Problems encountered in the use of rack and pinion
1. The noise becomes louder
Possible causes include damage to the gear drive, incorrect installation of the rack and pinion, or failure of the lubrication. The corrective measures include checking the gear transmission, checking with reference to the installation steps, and checking the lubrication system.
2. Increased working temperature
Possible causes include improper design, overheating of the gear drive or excessive ambient temperature. The corrective measures include checking the design parameters, checking the transmission device, adding heat dissipation equipment and adding enough cooling equipment if necessary.
3. Lubricating oil leakage
Possible reasons include excessive lubricant quantity and leakage. Corrective measures include removing excess lubricant, correcting lubrication frequency and dosage, or checking the gear drive and lubrication system.
4. Friction cracks appear in gears
Possible reasons include poor lubrication of gears, poor environment, wrong lubricating oil, and magnetic influence. The corrective measures include correcting the lubrication frequency and dosage. It is recommended to use an automatic lubrication system. The environment should be kept clean and dry. Do not allow the rack to be affected by the external environment, use improper lubricating oil, and confirm that the gear and rack are not magnetic.
5. Broken gear
Possible reasons are overload, equipment collision, pitting corrosion on the tooth surface, poor lubrication, poor parallelism or perpendicularity. The corrective measures include checking the design parameters, ensuring that there are no foreign objects within the operating range of the equipment, the emergency stop device is normal, operating the equipment according to regulations, ensuring good lubrication within the operating range, and reconfirming the accuracy of the rack installation position.