Micropitting, pitting and wear are typical gear failure modes,which can occur on the flanks of slowly operated and highlystressed internal gears. However the calculationmethods for theflank load carrying capacity have mainly been established on thebasis of experimental investigations on external gears.
The target of a research project was to verify the applicationof these calculation models to internal gears. Therefore twoidentical back-to-back test rigs for internal gears have beendesigned, constructed and successfully used for gear running tests.These gear test rigs are especially designed for low and mediumcircumferential speeds and allow the testing of the flank loadcarrying capacity of spur and helical internal gears for differentpairings of materials at realistic stresses. The three planet gearsof the test rig are arranged uniformly across the circumference.Experimental and theoretical investigations regarding the loaddistribution across the face width, the contact pattern and theload sharing between the three planet gears have been carriedout.
Furthermore substantial theoretical investigations on thecharacteristics of internal gears were performed. Thereforeinternal and external spur gears were compared regarding theirgeometrical and kinematical differences as well as their impact onthe flank load. Based on the results of these theoreticalinvestigations an extensive test program of load stage tests andspeed stage tests on internal gears of different material,different finishing of the flanks and different operatingconditions has been carried out. Themain focus of this test programwas on the fatigue failures micropitting and wear at lowcircumferential speeds.
The paper describes the design and functionality of the newdeveloped test rigs for internal gears and shows basic results ofthe theoretical studies. Furthermore it presents basic examples ofexperimental test results.
- Edition:
- 11
- Published:
- 10/01/2011
- Number of Pages:
- 16
- File Size:
- 1 file , 1.1 MB
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