As compared to external toothings, the design fundamentals andstandards for proving the load-carrying capacity of internaltoothings have been little developed. Mostly only insufficientlyconsidered is the influence of stress in the toothed gear rim,which is essential in almost all cases. Also for the theoreticalborderline case of the infinitely thick toothed gear rim somedesign data are too inaccurate, since they are not based on theactual tooth fillet and on precise notch-stress calculations. Evenlarger are the deviations in elastically designed toothed gearrims.
This paper is to present results of investigations for the moreprecise determination of stress in the tooth root or the toothedgear rim of internal toothings specifically for their use inplanetary gearings. Proposals for the practical calculation areincluded. The results of calculation are confirmed by tests. Atfirst, the considerations concern borderline cases of load in aninfinitely thick toothed gear rim, whose mounting in the casing hasno influence on the stresses examined here (very elastic connectingelements).
On this basis, the case of the inner toothed gear rim with acylindrical connection contour is treated (the internal toothing ispositioned only on a part of the hollow cylinder). The influence ofthe connection contours on the stress as compared with the versionwith a ground contour was successfully taken into account byapproximation relations. The assumptions and results of calculationwere well determined by measurements done on a planetarygearing.
The stress calculations are carried out by a locus-dependentsuperposition of the stress components resulting from the radiaiforce and the tangential force. Proceeding from the moment curveand longitudinal-force curve determined in the tooth gear rim, thelocal stress in the tooth gullet is determined with the aid of theboundary element method. The practical application of the findingsis facilitated by generalized stress concentration factors, whichare newly calculated for internal toothings.
To sum up, it can be stated that the contribution gives aninsight into general connections and proposes a refined method forpractical use.
- Edition:
- 97
- Published:
- 11/01/1997
- Number of Pages:
- 12
- File Size:
- 1 file , 440 KB
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