Excessive gearbox temperature rise is a common symptom during the operation of used strip steel slitting machines, and abnormal gear mesh clearance is often the key factor causing this problem. Since used equipment has undergone previous operation, gears may be subject to wear, deformation, or assembly deviations. Accurately measuring mesh clearance is crucial to ensuring stable operation. The following systematically explains the process for measuring gear mesh clearance in used strip steel slitting machines, including the testing principles, method selection, key operating points, and result analysis.
Gear mesh clearance directly affects transmission efficiency and thermal balance. Too little clearance increases friction on the gear tooth surfaces, generating excessive heat; too much clearance can induce impact loads, also leading to abnormal temperature rise. In used strip steel slitting machines, the gears in the gearboxes are subjected to long-term alternating loads, which can cause pitting, scuffing, or wear on the tooth surfaces. These hidden damages can alter the original clearance and require specialized testing methods to identify.
Common methods for measuring gear mesh clearance include the feeler gauge method, the lead pressure method, and the dial indicator method. The feeler gauge method is suitable for quickly checking visible clearances, but due to the limitations of tooth shape and operating space, its effectiveness in inspecting hidden areas in used equipment is limited. The lead pressure method, by placing a lead wire and measuring the thickness after flattening, can simultaneously determine both top and side clearances. This method is particularly suitable for inspecting gears with larger modules in used equipment. The dial indicator method indirectly calculates clearance by measuring the amount of gear play during rotation, making it suitable for applications requiring high precision. For used strip steel slitting machines, a combination of the lead pressure method and the dial indicator method is recommended for optimal accuracy and operability.
When using the lead pressure method, select a lead wire with a diameter slightly smaller than the expected clearance and ensure that its length covers the entire width of the tooth. After evenly placing the lead wire at the gear meshing area, slowly rotate the input shaft to fully compress the lead wire. After removing it, use a micrometer to measure the thickness of the lead wire at its thinnest point. Average multiple measurements to minimize error. For used equipment, pay special attention to positioning the lead wire away from damaged areas on the tooth surface to avoid distorted measurements.
The key to the dial indicator method is to secure the lower gear and move the upper gear shaft to cause the dial indicator pointer to swing. The maximum swing in both the forward and reverse directions is recorded; the difference is the backlash. This method requires high equipment condition and ensures that the gear and shaft system are well aligned; otherwise, additional errors may be introduced. For used strip steel slitting machines, bearing clearance and coupling alignment should be checked before testing, and pre-adjusted if necessary.
The validity of the test results should be determined based on the original equipment parameters and industry standards. If the measured clearance exceeds the design allowable range, it may be caused by gear wear, shaft deformation, or assembly errors. For used equipment, the impact of previous use on gear material properties must also be considered. For example, a decrease in hardness may indirectly alter the clearance characteristics. In this case, a combination of hardness testing and metallographic analysis should be used to assist in determining the root cause of the clearance abnormality.
For clearance issues discovered during testing, the repair strategy must balance cost-effectiveness and effectiveness. If the clearance is only slightly out of specification, it can be improved by adjusting the shim thickness or optimizing the lubrication conditions. However, if the gear is severely worn, replacement should be considered. After repair, used strip steel slitting machines should undergo no-load and loaded operating tests to monitor temperature rise and vibration data to verify the repair effectiveness.
Inspecting the gear meshing clearance of a used strip steel slitting machine's reduction gearbox is a systematic task. Appropriate testing methods must be selected based on the equipment's historical operating conditions and strictly adhered to operating procedures. Scientific testing and precise repairs can not only resolve excessive temperature rise issues but also extend the equipment's service life, ensuring the efficient operation of the used strip steel slitting machine.
