Workpiece clamping

As shown in Figure 2, two eccentric gears of the same platform are laid flat on the worktable of the gantry milling machine in the same direction, and contour pads are placed under the eccentric gears. When placing, try to make the eccentric part and the axis of the center hole and the reference tooth The centers are on the same line. With the reference tooth as the center, count the same arbitrary number of teeth on both sides, and the mandrel is adsorbed in the tooth groove through the magnetic table holder.

2.3.2 Alignment of workpiece

Firstly, after aligning the side generatrix of the center hole, press the workpiece slightly, and then pull the lowest point of the mandrel on the spindle of the machine tool with the dial indicator so that the lowest point of the mandrel is on the same straight line. If the value of the observation table is not equal, fasten it in the T-slot through the L-shaped pressure plate, and make fine adjustments by passing the screw through the tooth surface of the eccentric gear on the top of the L-shaped pressure plate until the value of the dial indicator remains unchanged. The left and right sides of the gear centered on the reference tooth have been adjusted so as to ensure that the center of the tooth tip groove, the center of the hole, and the center of the eccentric body are connected on the same straight line. Then the workpiece is pressed tightly, and the center hole is checked. After the clamping and alignment is completed, the next step of processing is started.

2.3.3 Milling eccentric datum

After installing the cutter head on the spindle of the machine tool, first align the center of the center hole, and then offset the eccentric distance to the eccentric part to determine the center of the eccentric part, and mill the datum on the upper end of the eccentric part for subsequent lathe processing and alignment. Because the eccentric datum is milled by the same distance to the same side of the machine tool, the influence of the machine gap can be eliminated, so as to ensure that the eccentric distance of the two pieces of the same machine is equal. This processing method is simple and efficient, and the measurement error is small, the level of requirements for the operator is reduced, and the processing requirements of two eccentric gears on the same set can be relatively easily guaranteed.

2.4 Processing considerations

When processing, you need to pay attention to the following:

①As the normal process flow of parts processing, before using the above method to process parts, it is necessary to mark the blank and align the line according to the line, and the marking must be accurate and serious. After finding the highest point of the eccentric outer circle part of the blank on the lathe, click this line. Before hobbing, be sure to press this line as the hobbing center to ensure the subsequent turning allowance of the eccentric part.

②Because the eccentric gear is welded by dissimilar steel, after the welding stress is removed, the gear is hobbed, and attention must be paid to the release of the stress when hobbing, so as to prevent the stress deformation from causing insufficient grinding allowance, which will affect the reference tooth profile of the mandrel adsorption. Precision.

3 Check critical dimensions

After the processing is completed, the key dimensions of the eccentric gear need to be inspected on the three coordinates to verify the rationality of the processing method. Similarly, the tolerance of the line connecting the center of the tooth tip, the center of the hole, and the center of the eccentric body on the same straight line is detected by the mandrel method. As shown in Figure 3.

The eccentricity of the two eccentric gears on the same platform and the tolerance of the center of the tooth groove, the center of the hole, and the center of the eccentric body on the same straight line through the three-coordinate detection are in line with the requirements of the drawing, thus verifying the eccentricity of the spindle method. The rationality of gears.

4 Conclusion

This article mainly studies the application of mandrel method in the processing and inspection of eccentric gears, and introduces the processing process and precautions of this method in detail. The eccentric gear processed in accordance with the above process flow is proved by inspection and full-load test of the press to fully meet the requirements of production and processing.

This method provides an effective guarantee for the accuracy of the entire heavy-duty press, reduces rework caused by processing errors in the past, saves processing and assembly time, and improves the company's economic benefits.