1. Feeler gauge method: This method can directly measure the top and side clearances of gears. Fill the feeler gauge on the tooth side of the gear, and the thickness of the feeler gauge is the meshing clearance.
2. Dial gauge method: This method can indirectly measure the backlash of spur gears. Fix the lower gear and rotate the lever slightly in both directions on the upper gear shaft. The pointer on the dial indicator swings in both directions, and the reading obtained is the side clearance.
3. Lead pressing method: This is the most commonly used method for measuring top and side gaps. Place the lead wire on the gear, then mesh and roll the gear. The thickness of the flattened lead wire is equivalent to the values of the top and side clearances. The thickness of the lead wire can be measured using a vernier caliper or micrometer. The thickness of the thickest part of the lead wire is the top gap, and the sum of the thicknesses of the adjacent thinner parts is the side gap. For large wide gears, it is necessary to place two or more lead wires in order to accurately measure the meshing clearance. At this point, not only can the clearance be checked based on it, but also the parallelism of the gear axis can be checked.
4. Dial gauge method: This is a relatively accurate measurement method. The gear shaft of a general reducer has a threaded center hole, and a measuring rod with a thread that matches the center hole is made. The measuring rod is rigidly connected to a straight edge with dimensions at a right angle. When measuring, screw the measuring rod onto the end of the shaft and lock it with a nut. Then, contact the contact pin of the dial gauge with the corresponding size of the measuring rod according to the pitch radius of the gear. Gently rotate the gear shaft back and forth by hand. The gear rotates within the meshing clearance area, and the gear shaft drives the measuring rod to rotate. The distance of the measuring point on the measuring rod is the gear meshing clearance, which can be directly read from the dial gauge.