The sources of gear errors are as follows: machining deviation, measurement deviation and wear deviation. In terms of machining, the double circular arc gear of the pumping unit is machined by machine tool hobbing, and the wear and repeated clamping of the hob will affect the accuracy of the helix angle. Source of software fitting error: establishment of coordinate system, sampling density and quantity, influence of field division, fitting measurement of addendum circle and dedendum circle. The other is the wear deviation of double circular arc gear. If the gear shaft and gear in the reducer are operated for a long time, tooth breakage, pitting, tooth surface peeling and plastic deformation will occur. The tooth profile deviation of double circular arc gear is analyzed to judge the wear of gear teeth. Geomagic Control X software can realize the CAD design model of parts and the deviation analysis of product manufacturing parts.
The set tolerance is ± 0.1 mm, and the analysis results are shown in Figure 1. Most areas of the double circular arc gear are within the set tolerance range, and there is no problem of tooth breakage, gear tooth breakage and tooth surface falling off as a whole. However, angle collapse occurs at the end face of the double circular arc gear, and some areas of the tooth top are worn, as shown in the blue area.
Set the tolerance to 0 02 mm, measure the deviation area at selected points, and the results are shown in Figure 2. For the working tooth surface, the tooth surface in the lower part of the convex arc tooth surface is lower than the theoretical tooth surface, and the selected point measurement deviation is – 0 037 4 mm, the upper part of convex arc tooth surface is higher than the theoretical tooth surface, and the measurement deviation is 0 073 mm, the tooth surface in the lower part of the concave arc tooth surface is lower than the theoretical tooth surface, and the selected point measurement deviation is – 0 034 2mm。 The working tooth surface has a certain plastic deformation.
The tooth profile deviation is further analyzed. The tooth profile of the gear tooth end face is analyzed. The end plane of the double circular arc gear is selected as the reference plane, and a plane is established at a distance of 5 mm from the end face, where the tooth profile of the end section is measured. Figure 3 shows the measurement of the deviation of the convex and concave arc surfaces on the tooth profile of the end face of the double circular arc gear and on both sides of the tooth. The results show that plastic deformation occurs on both sides of the working tooth surface.