This report investigates the wear morphology on the large end of tapered rollers and the inner ring's large end rib on a planet carrier TRB from a multi-megawatt wind turbine gearbox. The literature on abrasive wear has many classifications, including 2-body abrasion, 3-body abrasion, scratches, grooving abrasion, rolling abrasion, cutting abrasion, and plowing abrasion. For this analysis, we have selected grooving abrasion, a common problem in wind turbine gearboxes and a prominent failure mode on many bearings, particularly planetary carrier bearings and planet bearings. Grooving abrasion is frequently observed on cylindrical roller bearings (CRB) and tapered roller bearings (TRB). Fitzsimmons and Clevenger conducted tests on roller end/rib wear for TRBs with contaminated gear oil, and they provided an excellent explanation of the mechanism.

This paper presented some steps to get more insight into the effect of meshing damping on the dynamic response and noise emission of a two-stage gearbox transmission system. For this purpose, two variants of the model with different gear materials, one with plastic gears and one with steel gears, were considered. Both variants were designed for the same number of cycles of operation with similar root and flank safeties. The forced response analysis of the models was carried out and the exciting reaction bearing forces were calculated to evaluate which model can achieve better NVH characteristics results with lower noise emission from the housing.

Tactile or contact probes are the most common metrology technique in the coordinate measurement world, including the more specialized gear measurement community. Tactile probes can be active or passive, scanning or touch only, and may vary in cost and performance depending on the system itself. They are offered by multiple industrial companies as standalone OEM products (e.g., Renishaw) or only included in their coordinate measuring machines (e.g., Zeiss, Klingelnberg, and Hexagon). Their overall performance, especially their robustness and flexibility, have led to a gold standard for most metrology tasks.

Gear skiving is used for both soft and hard finishing. As a quality critical final step in hard finishing, the process can be used to create modifications to the tooth flank. At present there is no knowledge of the extent to which topological modifications can be applied by gear skiving. In this report, the feasibility of manufacturing topological modifications on an external gear through adapted kinematics for gear skiving has been investigated.

As the challenges in bevel and hypoid gear manufacturing need to be addressed, the objective of this paper is to show the tool and process design can be optimized based on the results of the manufacturing simulation BevelCut.

The main objective of this study is to perform an experimental evaluation of the structural model of a five-planet first planetary stage from a modern 6MW wind turbine gearbox.

This paper deals with the residual stress depth profiles in case-carburized gears, their effects on the fatigue behavior as well as the enhancement of ISO/TS 6336-4 to include the consideration of tensile residual stresses in the tooth core area. For this purpose, an equation is also presented with which these tensile residual stresses can be estimated so that they can be used in the enhanced evaluation of TFF risk.

This report discusses grain size and its influence on metallurgical properties including its effect on yield strength, ultimate strength, fatigue strength, and fracture toughness. Also discussed are manufacturing issues such as heat treatment, hardenability, and machinability. 

Bevel gears are widely used in various industrial applications, such as automotive, aerospace, and marine industries, due to their ability to transfer power between non-parallel shafts. The conventional manufacturing of bevel gears involves several time-consuming and costly processes, including gear blank preparation, gear cutting, and gear finishing. The increasing demands on gear components regarding increasing power density, reducing installation space, reducing weight, and increasing efficiency are also reflected in the design of gear components. The reduction of installation space and weight as well as the increase in power density often leads to an optimized wheel body design that interacts with the gearing in terms of load capacity and stiffness. This leads to an increase in the required geometric degrees of freedom (DOFs). Due to the resulting complex wheel body shapes and different production-related effects, production-related geometry adjustments may also be necessary. Tools for evaluating the gearing in combination with the wheel body shape and its influences nowadays form the basis for unlocking the holistic optimization potential of transmission components. 

The objective of this report is to determine the origin of the phrase “profile shift.” Several technical books, technical papers, and industrial standards were reviewed for nomenclature associated with profile shift. The phrase “profile shift” translates directly to the German term “Profilverschiebung,” which originated in the last quarter of the 19th century. At first, profile shift was used to avoid undercutting pinions with small numbers of teeth. Later, it was recognized that profile shift improved the load capacity of the gear mesh and extended the service life of manufacturing tools.