Production and design of gears according to sample parts or drawings

Production and design of gears according to sample parts or drawings

Today we were with Michael Dürlamm, our master craftsman, who has been managing the gearing department since 1999. Among other things, he deals with the gear design of sample parts at TANDLER and we wanted to learn more about it.

Moin Michael, could you describe to us how gear design of bevel gears is done according to sample parts at TANDLER?

The customer sends us a gear set and asks if we can produce exactly this gearing. When it comes to curved-tooth bevel gears, they end up with me. First I start counting the teeth and determining the spiral direction. Then follows the measuring of outer diameter, inner diameter, tooth width etc. These are the basic data for the gear calculation program "KIMOS" from Klingelnberg. When the calculation in KIMOS is finished, we have all the data, so-called neutral data, which we need for the production of the gear set. These neutral data can be read in by the measuring machine, the bevel gear milling machine and the bevel gear grinding machine. Then I take the sample parts to the measuring machine and check whether what Kimos has calculated corresponds to the sample gear set. I get a measuring diagram showing the deviations from the sample parts to the neutral data calculated in KIMOS.

Is it possible that the measured values deviate?

Yes, this is not unusual, e.g. deviations in the spiral angle. The spiral angle shows how skewed the tooth on the wheel body is. The spiral angle has a decisive influence on the bearing forces that occur. If the spiral angle is not correct, the bearings can break down very quickly. At first sight you cannot see the exact spiral angle, so we have to measure on the testing machine and the spiral angle. Then we may have to go back to KIMOS to adjust the spiral angle to the measurement diagram in the gear design. This cycle, correction of gear design, new measurement, must be repeated a few times to ensure as few deviations as possible between gear design and sample parts. Then the sample part is sent to the laboratory of our in-house hardening shop for material determination.

Michael Dürlamm, our master craftsman of the gearing department
Michael Dürlamm has been head of our gearing department since 1999.

What comes next?

Afterwards I check whether all tools are ready for the production of the gear teeth and give the sales department the confirmation that we can reproduce the gear set. Then an offer is sent to the customer. If the customer is ok with it, from the sketches, drawings with all manufacturing tolerances are made and the wheel bodies go into production.

For gear milling, gear grinding and measuring, the neutral data previously created on the sample parts are now used. After gear cutting, the wheel bodies go to the hardening shop, then to grinding and finally to the final inspection.

Can customers also send us a drawing instead of a sample part?

Yes of course, in that case we have to read the required input values in KIMOS from the drawing. The procedure is the same as for the sample parts after the data input in KIMOS.

Is it possible that we design and produce gears better than the gears the customer has given us?

This may well be the case! Already in the design phase we can see the contact pattern in KIMOS and, if necessary, make modifications. If we have found that the contact pattern of the sample gear set is no longer optimal, we can offer our customer an improved version to improve the running characteristics and guarantee the longest possible service life. This means that we can not only reproduce a sample part but also optimise it. Of course, this also applies to the choice of material. This can also increase the strength and thus the service life, in some cases considerably.

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