Core Competence
Application-Oriented Testing Methods


In order to design gears to fit a certain market requirement, the knowledge of the running behavior which is the load carrying capacity, the excitation behavior and the efficiency is of great importance. To obtain precise results, the test rig has to be adjusted to fit a test gear in order to detect all the influences specific to that test gear. Standard testing rigs are not always suitable for this task.

Standard test rigs are normally used for the determination of isolated influences regarding load carrying capacity and efficiency. These are back-to-back test rigs with a fixed center distance. With these test rigs, influences of the material, heat treatment, running conditions and manufacturing processes on the load carrying capacity and the efficiency are tested using standard reference gears. In addition, oil tests regarding scuffing, micropitting and pitting are performed with standardized testing gears. Additionally to standard test-rigs, analogy test rigs are used at the WZL . For simulating effects of the tribological system gear the two-disk test rig is used, which represent the rolling contact at a specific location on the tooth flank to perform efficient comparisons between different materials, heat treatments and lubricants in respect to load carrying capacity as well as efficiency. To test the tooth root load carrying capacity, the pulsator test is used as an analogy test. By testing spur gears, influences resulting from different materials or heat treatments on the tooth root load carrying capacity are determined.
All the aforementioned testing methods use either analogy test samples or reference gears which do not coincide with the original gear. Some properties specific to the gear are therefore not tested on standard and analogy testing rigs.

The aim of application-oriented testing is to first manufacture the original gear and then test the original gear thus substituting reference gears. This applies to testing load carrying capacity as well as testing efficiency and excitation behavior. In any case the test rigs should provide comparable testing methods to the standard test rigs.

The WZL counts with extensive solutions for testing application-oriented gears. To test the tooth root and the tooth flank load carrying capacity, the so-called 3-shaft test rig with a flexible center distance is used. The analogy test method to test the tooth root load carrying capacity which is conducted on the pulsator test rig was altered such that also helical gears can be tested at WZL using a special fixture.
To test excitation behavior and efficiency, special gear measuring cells are used, in which spur gears, planetary gear stages and bevel gears are electrically loaded and the running behavior is measured with extensive measuring equipment. The efficiency is tested with the power difference measurement. On the other hand, test rigs are used in which the entire gear box can be placed and tested. By using a noise-cancelling chamber, not only the structure-borne noise, but also the unobstructed air-borne noise can be measured and analyzed. By means of all the aforementioned testing methods, it is possible to test the load carrying capacity, the excitation behavior as well as the efficiency of industrial used gear designs in an application-oriented manner, without the use of reference gears.

The Aim: Individual Solutions
- Load carrying capacity tests using your gears, which are manufactured according to your original design
- Analysis of the excitation behavior and the efficiency on test rigs that are adapted to fit your gear
- Investigation of the excitation behavior of entire gearboxes in a low-noise environment


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