The common calculation methods according to DIN 3990 and
ISO 6336 are based on a comparison of occurring stress and
allowable stress. The influence of gear size on the load-carrying
capacity is considered with the size factors YX (tooth root bending)
and ZX (pitting), but there are further influences, which
should be considered.
In the following, major influences of gear size on the load factors
as well as on the permissible tooth root bending and contact
stress will be discussed.
The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness defined as the ratio of lubricant
film thickness to the composite surface roughness. It can be difficult to combine results of studies to create a cohesive and comprehensive data set. In this work gear surface fatigue lives for a wide range of specific film values were studied using tests done with common rigs, speeds, lubricant temperatures, and test procedures.
Flank breakage is common in a number of cylindrical and bevel gear applications. This paper introduces a relevant, physically based calculation method to evaluate flank breakage risk vs. pitting
risk. Verification of this new method through testing is demonstrably shown.
In this study, limiting values for the load-carrying-capacity of fine-module gears within the module range 0.3–1.0 mm were determined and evaluated by comprehensive, experimental investigations that employed technical, manufacturing and material influence parameters.
The powder metal (P/M) process is making inroads in automotive transmission applications due to substantially lower costs of P/M-steel components for high-volume production, as compared to wrought or forged steel parts. Although P/M gears are increasingly used in powered hand tools, gear pumps and as accessory components in automotive transmissions, P/M-steel gears are currently in
limited use in vehicle transmission applications. The primary objective of this project was to develop high-strength P/M-steel gears with bending fatigue, impact resistance and pitting fatigue performance
equivalent to current wrought steel gears.
No matter how well gears are designed and manufactured, gear corrosion can occur that may easily result in catastrophic failure. Since corrosion is a sporadic and rare event and often difficult to observe in the root fillet region or in finely pitched gears with normal visual inspection, it may easily go undetected. This paper
presents the results of an incident
that occurred in a gear manufacturing
facility several years ago that resulted in pitting corrosion and intergranular attack (IGA).
In this paper, a method is presented for analyzing and documenting the pitting failure of spur and helical gears through digital photography and automatic computerized evaluation of the damaged tooth fl ank surface. The authors have developed an accurate,
cost-effective testing procedure that provides an alternative to vibration analysis or oil debris methods commonly used in conjunction with similar test-rig programs.
In earlier studies, surface roughness has been shown to have a significant influence on gear pitting life. This paper discusses how high surface roughness introduces a wear mechanism that delays the formation of pits. Accompanied by a full-page technical review.