Timken (United States)

This paper evaluates the challenges and solutions associated with the 2.3 MW wind generator class, a widely deployed platform that remains critical to renewable energy infrastructure. As the installed base of wind generators continues to expand, ensuring long-term reliability and efficiency becomes a key priority for operators. This study identifies common failure modes and investigates engineering design improvements aimed at enhancing reliability, reducing repair complexity, and lowering overall lifecycle costs. A primary challenge in assessing wind generator performance is the lack of detailed efficiency and loss breakdowns from OEMs, making direct validation difficult. To address this, the paper introduces a novel analytical design comparison methodology, leveraging proprietary modeling tools to quantify loss reductions. The approach enables accurate performance assessment without requiring proprietary OEM data, offering a robust alternative for improving generator reliability and extending mean time between failures (MTBF). A new stator core and winding design is presented that demonstrates significant reductions in losses and temperature increases, leading to improved efficiency and extended generator lifespan. The research integrates insights from previous studies on motor losses and reliability improvements, further validating the proposed modifications.

<div class="section abstract"><div class="htmlview paragraph">One often reported roadblock to consumer acceptance of electric vehicles is driving range, which is a function of powertrain efficiency and vehicle mass. Electric vehicle gearbox design often is based on multiple parallel shafts, thereby creating significant packaging constraints. Industry perception holds that deep groove ball bearings (DGBB) are more efficient than tapered roller bearings (TRB), and standard spin-loss testing confirms those beliefs. However, spin-loss efficiency testing does not accurately reproduce typical real-world driving. A more realistic comparison of bearing efficiency is required to properly select bearings during the powertrain design stage.</div><div class="htmlview paragraph">Recently completed testing focused on recreating application conditions (including bearing loads, speeds, misalignment, and load zones) for electric vehicle gearbox intermediate shafts. These conditions varied between TRB and DGBB as a result of application bearing setting and reaction load changes and were faithfully reproduced. Under light load conditions, power loss from a 35 mm DGBB was significantly lower than that of a 35 mm bore TRB, but the TRB power loss was significantly lower than the DGBB’s under heavier loads.</div><div class="htmlview paragraph">When the individual test conditions were weighted to represent a road-use cycle, weighted power loss was equivalent between the two bearing types at expected vehicle operating temperatures. The bearings had the same rated radial capacity, but the TRB had reduced width, outer diameter (OD), and mass. The TRB’s capability of exhibiting power loss equivalent to the DGBB but within a smaller required envelope size can significantly aid electric vehicle design engineers who are faced with fitting multiple parallel shafts in their applications. In addition, the reduced size of the TRB allows system mass reductions, increasing battery range to address consumer concerns.</div></div>

The microstructural evolution of and simultaneous dimensional changes in high-carbon SAE 52100 bearing steel were monitored continuously during austempering for 120 min at selected temperatures in the range of 210 °C-270 °C, and also during its subsequent tempering to 340 °C for an additional 120 min, via high-energy X-ray diffraction in real time and in-situ dilatometry. The austenite-to-bainitic ferrite transformation induces lattice defects and internal lattice stresses that increase with austempering time and at lower austempering temperatures. These changes are evidenced by the increase in the full-width half-maximum of the relevant reflections in X-ray diffraction. The lattice parameter of bainitic ferrite takes its highest value during the early stages of austempering, and then gradually decreases as the transformation progresses. This observation points to an initial state of carbon supersaturation in the ferritic lattice that is likely reducing due to carbon segregation close to dislocations, fine carbide precipitation within the bainitic ferrite, and carbon partitioning into the surrounding austenite. The carbon partitioning into austenite is evidenced in particular at the higher austempering temperatures of 240 °C and 270 °C, at which there is a noticeable increase in the lattice parameter of the remaining austenite at longer times. The dimensions of the bearing steel specimens are governed by the volume change due to the formation of bainitic ferrite during austempering and by the relaxation of its lattice distortion during tempering at 340 °C in the absence of further phase transformation.

Liquid crystal elastomers (LCEs) hold a major promise as a versatile material platform for smart soft coatings since their orientational order can be predesigned to program a desired dynamic profile. In this work, we introduce temperature-responsive dynamic coatings based on LCEs with arrays of singular defects-disclinations that run parallel to the surface. The disclinations form in response to antagonistic patterns of the molecular orientation at the top and bottom surfaces, imposed by the plasmonic mask photoalignment. Upon heating, an initially flat LCE coating develops linear microchannels located above each disclination. The stimulus that causes a non-flat profile of LCE coatings upon heating is the activation force induced by the gradients of molecular orientation around disclinations. To describe the formation of microchannels and their thermal response, we adopt a Frank–Oseen model of disclinations in a patterned director field and propose a linear elasticity theory to connect the complex spatially varying molecular orientation to the displacements of the LCE. The thermo-responsive surface profiles predicted by the theory and by the finite element modeling are in good agreement with the experimental data; in particular, higher gradients of molecular orientation produce a stronger modulation of the coating profile. The elastic theory and the finite element simulations allow us to estimate the material parameter that characterizes the elastomer coating's response to the thermal activation. The disclination-containing LCEs show potential as soft dynamic coatings with a predesigned responsive surface profile.

The purpose of this research is to clarify the influence of difference in size of horizontal diaphragm on shear performance. The subject of research is horizontal diaphragm reinforced with shear key along CLT joints. At first, we confirmed the influence of difference in size of horizontal diaphragm on shear performance by experiment. Next, we confirmed it by numerical analysis of many patterns. As a result, the influence of difference in size of horizontal diaphragm on shear performance was shown.