This paper presents a method for estimating the fatigue life of crossed roller bearings (XRBs). XRBs feature a single row of rollers arranged alternately at right angles, making them ideal for applications that require high precision and a compact design. In rolling-element bearings, fatigue life is a crucial design parameter for ensuring long-term reliability and performance. However, existing fatigue life estimation models for XRBs in the literature are limited to basic rating life, with no models available for reference rating life. To address this gap, we developed a comprehensive fatigue life prediction model specifically for XRBs. We formulated a corresponding dynamic load rating to align with the values provided by bearing manufacturers and calibrated an unknown adjustment factor for XRBs using a commercial program. Additionally, a parametric study was conducted to investigate the impact of varying diametral clearance, external loads, roller dimensions, and roller profile parameters on the fatigue life of XRBs.

In the case of TV products, space constraints and design requirements make it advantageous to use a worm gear that has a small volume and a self-locking function. Single enveloping worm gear teeth are classified as ZA, ZN, ZK, ZI, and ZC according to international standards. However, combining worm shafts and worm wheels with different tooth profiles can significantly worsen meshing transmission errors and reduce the lifespan of the worm gear. Despite these challenges, due to processing limitations, ease of manufacturing, and cost reduction, combinations of worm shafts and worm wheels with different tooth profiles are still considered. In this study, we confirmed the meshing transmission error for a worm gear that combined a ZA tooth shape worm shaft with a ZI tooth shape worm wheel. Additionally, we examined the contact stress and fatigue life characteristics of the material combinations using finite element analysis (FEM).

When a workpiece contains complex burr edges from a combination of drilling and milling, conventional deburring tools such as wire brushes may not be effective in their removal. In this study, abrasive flow machining was used to gain access to complex burr edges. Experiments on two types of flow guides suggest that an abrupt change in direction of flow around the area with targeted burr edges is essential. The effects of several process parameters are investigated based on the experiments set up.