# A new method for the most accurate measurement of

2022-09-19
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A new method for accurately measuring the helical angle of helical gears (2)

determination of helical angle Ba: when selecting the change gear according to the above formula, we often encounter the situation that the calculation is complex and some data are difficult to decompose. In order to simplify the calculation, some data can be appropriately selected or rejected. In this way, the helical angle formed during the movement of the indexing head milling machine workbench system of the selected change gear is no longer the helical angle Ba during rough measurement, but the helical angle BA (tooth top) is calculated

ba =arcsin (pmnz/40ti), where i= (a/b) x (c/d) gear change mechanism transmission ratio

determines the measurement error compensation angle g. we call the difference g between the actual helix angle Ba of the measured gear top and the calculated helix angle Ba of the gear top as the measurement error compensation angle. Therefore, the method of measuring and measuring the error compensation angle G is to use the contact of the dial indicator to push on the tooth surface at the measured gear top (see Figure 2). Shake the handle of the dividing head to rotate the gear and move the worktable at the same time. The moving distance L of the worktable can be read out from the scale on the worktable of the expandable data collection channel of the Industrial Research Institute (l=nk). The experimental machine adopts a microcomputer to process and analyze the data. The displacement D in the vertical direction of the spiral line at the top of the tooth of the meter can be read out on the dial indicator. The measurement principle of the spiral line after expansion is shown in Figure 3

tgg=d/s=d/lcosba g=arctg[(dcosba)/l], in which: the length of the spiral line of the s measuring section after expansion

determination of the actual spiral angle at the top of the gear tooth: it can be seen from Figure 3 that the actual spiral angle at the top of the gear tooth

ba=ba g=ba arctg[(dcosba)/l] (take + sign at d 0; take - sign at d 0)

determination of the spiral angle at the dividing circle of the gear: the spiral angle of the gear at the dividing circle can be derived according to the geometric parameters of the gear, According to figure 4, there is

tgb=rtgba/ra, then b=arctg[(RA mnha) tgba]/ra. In the formula: R gear sub strives to build a modern material industry system with optimized structure, advanced technology, supporting services and friendly environment. The radius of the circle of RA gear tip is

because the straight diameter of the indexing circle of the modified gear is equal to the diameter of the indexing circle of the non modified gear, whether the gear is modified has no effect on the helical angle of the helical gear, Therefore, the measurement method of its helix angle is also applicable

measure on the gear hobbing machine. Install the measured gear on the workbench of the gear hobbing machine. Stick the magnetic base of the dial indicator on the hob frame, and the contact of the dial indicator is on the tooth surface at the top of the gear tooth to be measured. Select the change gear according to the rough spiral angle Ba of the tooth top. When selecting the change gear, due to the different model of gear hobbing machine used, the replacement formula is also different. Select the differential change gear on Y3150 gear hobbing machine according to the following formula: A2 c2=9sinba

b2d2mnk

select the differential change gear on Y38 gear hobbing machine according to the following formula: A2 c2=7.9577sinba

b2d2mnk select the differential change gear on Y3180 gear hobbing machine according to the following formula: A2 c2=6sinba

b2d2mnin this formula: A2, B2, C2, D2 select the number of teeth of change gear

mn the method of measured gear.The surface modulus K assumes that the number of hobs during machining (k=1 or k=2) starts the gear hobbing machine after installation, Measure the displacement l of the tool rest and the displacement D of the head along the vertical direction of the tooth surface at the tooth top, and then determine the spiral angle BA at the tooth top and the spiral angle B at the indexing circle through calculation

ba=ba arctg[(dcosba)/lj] b=arctg[(RA mnha) tgba/ra]

in the formula, the calculated helix angle measured by BA (calculated by the transposition formula according to the model of the selected gear hobbing machine)

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