Special software designing for drawing of gear K-Sheet
(control chart) to increase of product quality
A. Mangouri, S. Chitsaz, R&D Dep., Charkheshgar Co, Tabriz, Iran;
Abstract
There are many tools for increasing durability, quality and decreasing noise and vibration of
gears at the step of designing, production and control. One of them is the gear Lead and
Profile control chart according to design and production parameters. There are different
procedures of gear control chart drawing in the standard documents such as ISO, AGMA [1]
and DIN, but they have not more detail and clarifications for some of the important
parameters such as lead & profile crowning, tapering, tip/root/end relief, chamfering , driver
and driven flank effect and other geometrical parameters to drawing the control charts.
Special software has been designed at the R&D department of Charkheshgar which is able
to cover all the mentioned parameters. Also, according to the practical results of different
type of gear manufacturing process, the corrections have been considered.
1. The reasons of project definition
Today, there are advanced tools for controlling the lead and profile of the gears by drawing
graphs according to the quality, accuracy and gears application which are able to reveal
allowed deviation range according to the related standards. For example In ISO &
ANSI/AGMA: 2000-A88 standards (figure 1) some of the mentioned diagrams (K-Sheets)
have been defined [2]. For achieving ideal quality, low noise and vibration, the specified
ranges in the mentioned standards, lead to the better results by adding some corrections and
limitations on the boundaries. This topic has been proven for several times by practical
experiments. In order to apply these corrections, the effective factors such as gear
production quality, geometric theory, gear engagement and gear designing parameters
should be considered. For accomplishing the above conditions, special software has been
designed.
Figure 1:
ANSI/AGMA: 2000-A88 diagram for tooth trace controlling [2]
2. Software work space and its abilities
At the figure 2, the work space of the CHK (Charkheshgar K-Sheet) software has been
showed. This user-friendly software has three major sections:
1- Input data which includes basic gear and its mate parameters.
2- The present box of lead and profile control diagram which are able to convert to CAD
format.
3- Four basically design deviations which are taken from transmission design and
calculations. These deviations have important influences on gear engagement quality
under the load conditions.[3]
Input data
Deviations Figure 2:
Lead diagram
Profile diagram
CHK-Software work space with example of lead and profile control diagram
3. Software advantages
As mentioned in section 1, depending on the defined ranges in standards, gear's lead and
profile controlling diagrams may need some changes in boundaries. For illustration of the
influence of profile K-Sheet boundaries on the gear noise level at the load condition, we used
dBFA- Harmony measurement system at the noise test center, as shown in figure 3.
Figure 3:
dBFA- Harmony measurement system installed at the noise test center
For this case we selected the input shaft of ZF S6-90 transmission with noise level near to
105 dB which achieved by the mentioned measuring system. According to the experience,
this level of noise is out of acceptable threshold for this part. To check the gear profile, its
profile trace has been taken by using of HÖFLER (gear special measurement tool) in
Charkheshgar. AGMA Control diagram of the tooth profile has been prepared by modeling of
the gear in KISSsoft software (figure 4). [4]
Figure 4:
modeling the input shaft gear in KISSsoft (left) and AGMA control profile (right)
According to figure 5, the graph is not in the limitation of the presented K-Sheet by AGMA
standard and CHK.
Figure5:
CHK graph (left), AGMA graph (middle) and corresponding noise level (right)
We have done some corrections on the profile of this gear by Reishaver (grinding machine)
to bring its profile graph in to the range of CHK K-Sheet. (Figure 6)
Figure6:
CHK graph (left), AGMA graph (middle) and corresponding noise level (right)
By applying the corrections, we have reached to almost 10 dB decreasing in noise which is
an acceptable level (figure 6). Because of grinding process, the new K-Sheets have been
drawn according to quality No. 6. As you see in the figure 6, the corrected graph is in the
limitation of CHK but it is not in range of AGMA control diagram. By comparing two K-Sheets,
it seems that we can apply some changes at boundaries against to AGMA diagram. CHK
software calculates the required correction according to the theoretical transmission
designing parameters and applies the changes to the control diagrams as in figure 6.
4. References
[1] ANSI/AGMA standard: 2015-1-A01, American National Standard.
[2] ANSI/AGMA standard: 2000-A88, gear classification and inspection handbook, July 1990.
[3] ZFN standard: 5005-1, (DE/EN): 2001-05, standard of ZF group, ZF Co. Germany.
[4] KISSsoft 08-2009 software, Charkheshgar License 954.