A new method for the most accurate measurement of

A new method for accurately measuring the helical angle of helical gears (I)

1. The problem of parts damage is often encountered in the process of machine maintenance and repair, and the parts that need to be replaced should be mapped and manufactured. Among them, there are some difficulties in measuring the helical angle of helical gears, mainly because it is difficult to measure the angle accurately without precision measuring instruments (tooth aligner, guider, tool display mirror, etc.)

2 the commonly used field measurement methods for helical gear helix angle are universal angle ruler side measurement method and indentation method

the universal angle ruler side measurement method is to use the universal angle ruler to measure the angle between the end face and the tooth surface of the gear to be measured. Because the helical angle of the gear changes with the radius of the gear, and the tooth groove of the general gear is narrow, the literature search has not found any reports of clinical results or complications of the device, and it is small. The cutter ruler of the universal angle ruler has a certain width, and the cutter ruler cannot be completely placed in the tooth groove, so it is difficult to determine the position of the graduation circle. Therefore, it is difficult to measure the angle accurately

the indentation method is to roll the tooth top of the tested gear on a piece of paper after it is colored, and the trace of the tooth top rolling is left on the paper. The extension line and auxiliary line of the tooth top line are made according to the indentation, and then the tooth direction angle is measured with a protractor. This angle is the spiral angle at the tooth top of the gear (see Figure 1), and then the spiral angle at the gear graduation circle is calculated according to other geometric parameters of the gear. Because the width of the gear is generally not large, the extension line and auxiliary line made have a certain width error, which is inevitable when measured with a protractor, and the scale of the protractor is in degrees. There is nothing that can be done for the measurement of angles accurate to minutes and seconds

3 new measurement method

first use the universal angle ruler measurement method or indentation method to roughly measure the spiral angle of the measured gear top, and then measure the approximate angle of the spiral angle of the gear top on the side, and then use the method of dividing head with change gear on the universal milling machine to control the process of single 1 to the automation of the whole factory or measure on the gear hobbing machine to determine the spiral angle at the gear top. Then the helix angle of the gear at the dividing circle is determined by calculation. The measurement method of determining the helix angle of the top of the gear is as follows:

determine on the universal milling machine

first measure the approximate value B of the helix angle of the top of the gear to be measured, and then roughly calculate the normal surface modulus Mn of the gear according to other measurement data (selected according to the standard value)

mn dn/[(Z/cosba+2ha] Where: z the number of teeth of the gear to be measured Da the diameter of the addendum circle of the gear to be measured ha the addendum height coefficient of the gear

install the dividing head and tailstock on the workbench of the universal milling machine, and then install the gear to be measured on the center of the dividing head and tailstock with a mandrel, and select the change gear according to the following formula:

screw holding force

a c=1 pmnz bd40t Sinba

where: A, B, C D the number of teeth of the selected change gear is 1/40, the transmission ratio of the dividing head, and the pitch of the lead screw of the T milling machine workbench (mm) is 3 The electromechanical phase sequence is not allowed to jump. T=nk n the number of grids turned on the dial of the milling machine workbench. K the moving egg of each grid of the milling machine workbench

after the change gear is matched, shake the handle of the dividing head, and the dividing head and the workbench will move together