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View article: Scuffing Calculation of Cylindrical Gears Facing Loss of Lubrication
Scuffing Calculation of Cylindrical Gears Facing Loss of Lubrication Open
Loss of lubrication in aeronautic drivetrains can lead to catastrophic gearbox failure, and drivetrains must be tested to prove their resistance to loss of lubrication. Research led to a better understanding of the modes of action, interde…
View article: Influence of high speeds on operating behavior of gears under loss of lubrication
Influence of high speeds on operating behavior of gears under loss of lubrication Open
Loss of lubrication in aeronautic drivetrains can be caused by failures in the oil supply system or by damage to the gearbox. This can lead to insufficient heat removal, scuffing, thermal runaway, and catastrophic transmission failure. To …
View article: Sensor-integrating gear wheel for in-situ measurement (SIZA)
Sensor-integrating gear wheel for in-situ measurement (SIZA) Open
Defects in machine components can result in costly machine downtime. Sensors are widely deployed to prevent this, and intelligent monitoring systems are implemented. However, these solutions are often custom-made, expensive, and difficult …
View article: Crack Propagation in Tooth Root: A Comparison Between Pulsator Test and Running Gears
Crack Propagation in Tooth Root: A Comparison Between Pulsator Test and Running Gears Open
Tooth root fatigue fracture is a critical gear failure mode in which the tooth root breaks because of the repetition of bending load. The most widely adopted procedure for evaluating root strength is through pulsator testing. However, this…
View article: Mixed and thermal elastohydrodynamic simulation of cylindrical gear designs
Mixed and thermal elastohydrodynamic simulation of cylindrical gear designs Open
In light of the current efforts to protect the climate and reduce CO 2 emissions, the reduction of load-dependent gear power loss and extension of lifetime are key objectives in gearbox design. In order to achieve this, accurate and detail…
View article: Investigations on the tooth root load-carrying capacity of carbonitrided gears containing high amounts of retained austenite
Investigations on the tooth root load-carrying capacity of carbonitrided gears containing high amounts of retained austenite Open
To ensure the quality and load-carrying capacity of case-hardened (or carbonitrided) gears, the permissible retained austenite content is limited to a maximum of 30 vol.-% in common design standards, such as ISO 6336 or ANSI/AGMA 2101. In …
View article: Influence of water evaporation on the power loss behavior of cylindrical gears lubricated by aqueous polyalkylene glycols
Influence of water evaporation on the power loss behavior of cylindrical gears lubricated by aqueous polyalkylene glycols Open
Aqueous polyalkylene glycols have demonstrated superlubricity in model and gear tests. One challenge for its application in gearboxes is water evaporation and absorption. This study investigated the influence of water evaporation and absor…
View article: Influence of centrifugal forces on the tooth root load carrying capacity of high-speed gears
Influence of centrifugal forces on the tooth root load carrying capacity of high-speed gears Open
In drivetrains of modern battery electric vehicles (BEVs), motor speeds exceeding 15,000 rpm are already common. In scientific research projects, motor speeds up to 50,000 rpm are being investigated. These very high motor speeds must be ha…
View article: Transformer for gear fault diagnosis enhancing robustness through physics-informed multi-task learning
Transformer for gear fault diagnosis enhancing robustness through physics-informed multi-task learning Open
The effective diagnosis of gear faults significantly reduces downtime and cost and enhances the reliability of rotating machines such as wind turbines. In recent years, deep learning models have been increasingly applied in gear diagnostic…
View article: Improved method for determining the experimental tooth friction coefficient of cylindrical worm gears
Improved method for determining the experimental tooth friction coefficient of cylindrical worm gears Open
Cylindrical worm gears with a shaft crossing angle of 90° are crucial in industrial applications where drive systems require high gear ratios within a compact installation space. For the design of worm gears, the friction behavior in the t…
View article: Advanced transmission optimization for new design challenges using RIKOR
Advanced transmission optimization for new design challenges using RIKOR Open
In many cases, gear and transmission design relies on application of standard calculations combined with comprehensive methods for loaded tooth contact analysis (LTCA). Results like local flank load distribution, transmission error and loc…
View article: Investigations on the thermal behavior of plastic crossed helical gears
Investigations on the thermal behavior of plastic crossed helical gears Open
Electric drives as compact as possible are in demand for a wide range of applications. In addition to being used as positioning drives in medical technology or robotics, such compact electric drives are increasingly used in transportation …
View article: Effects of Additives Adsorbed to Wet Clutch Disks on Their Tribological Performance Found in a Comparative Investigation
Effects of Additives Adsorbed to Wet Clutch Disks on Their Tribological Performance Found in a Comparative Investigation Open
Tribolayer build-up was investigated on wet clutch steel disks with experiments in three different test levels of the tribological verification chain via X-ray photoelectron spectroscopy. A new characteristic value of the tribolayers was d…
View article: Efficiency improvement potential of a BEV gearbox using a mono fluid circuit
Efficiency improvement potential of a BEV gearbox using a mono fluid circuit Open
In Battery Electric Vehicles (BEVs), energy dissipation can potentially be decreased by combining the cooling of electrical components and lubrication of the gearbox in a mono fluid circuit. This can be achieved by using novel fluids with …
View article: Investigations on the pitting load carrying capacity of worm wheels depending on load and sliding velocity
Investigations on the pitting load carrying capacity of worm wheels depending on load and sliding velocity Open
Worm gears are typically used in applications where a high transmission ratio is required in a small installation space. Furthermore, the use of this type of gearbox enables low-vibration and low-noise operation. A typical type of damage t…
View article: Characterization of bronze materials for worm gear drives
Characterization of bronze materials for worm gear drives Open
According to the current state of the art, wear and efficiency of worm gears can be calculated using ISO/TS 14521 [1] which is based on experimental investigations of the past decades. Concerning wear, the material properties of the typica…
View article: Machine Learning in Transmission Design
Machine Learning in Transmission Design Open
In the design process of gear systems, various computational tools are used to optimize the operational behavior. Due to time constraints, the initial stages of development typically assume ideal, deviation-free gear geometries. However, d…
View article: Machine Learning in Transmission Design
Machine Learning in Transmission Design Open
In the design process of gear systems, various computational tools are used to optimize the operational behavior. Due to time constraints, the initial stages of development typically assume ideal, deviation-free gear geometries. However, d…
View article: Mixed and thermal elastohydrodynamic simulation of a low-loss gear considering the gear system
Mixed and thermal elastohydrodynamic simulation of a low-loss gear considering the gear system Open
The reduction of load-dependent gear power loss is one of the key aspects in gear design. Therefore, a detailed power loss prediction and the local investigation of its drivers are essential. In this study, the model of Farrenkopf et al. i…
View article: Simulative and Experimental Investigation of Vibration Transfer Path at Gearboxes
Simulative and Experimental Investigation of Vibration Transfer Path at Gearboxes Open
Condition monitoring systems are widely used in gearboxes. Gears are one of the most crucial components for power transmission. Hence, the optimal sensor positions for condition monitoring of gears should be investigated to maximize reliab…
View article: A modelling approach for considering material and structural properties in the calculation of local tooth root endurance limit of case hardened gears
A modelling approach for considering material and structural properties in the calculation of local tooth root endurance limit of case hardened gears Open
Gear and gearbox design require reliable strength numbers to calculate the tooth root load carrying capacity. These values can be determined directly by experiments on the one hand, which is often associated with considerable effort and co…
View article: Tooth flank fracture in a wind turbine gearbox—A failure analysis
Tooth flank fracture in a wind turbine gearbox—A failure analysis Open
During the last two decades, electricity generation by wind power increased rapidly. This is mainly due to efforts to reach CO 2 neutrality and the low levelized cost of wind energy. Also, the power generated by a single wind turbine with …
View article: Elastohydrodynamic Lubrication Mechanisms of Aqueous Polyethylene Glycols
Elastohydrodynamic Lubrication Mechanisms of Aqueous Polyethylene Glycols Open
Water-soluble polyalkylene glycols have become a growing subject of research to achieve liquid superlubricity in elastohydrodynamically lubricated contacts. While the influence of various factors, including water content and viscosity, has…
View article: Drag Losses of Wet Brakes and Clutches—A Scoping Review
Drag Losses of Wet Brakes and Clutches—A Scoping Review Open
Wet brakes and clutches are crucial drivetrain components widely used in many sectors. However, their drag losses can account for a considerable share of the overall drivetrain losses. Therefore, investigation of the drag loss behavior of …