Abstract. The friction torque inside the high-speed spindle bearing determines the performance of the friction, wear, heat, temperature rise and life of the bearing. Aim to analyze the high-speed spindle bearing dynamic characteristics, considering the influence of cage and internal lubricating oil-film, a quasi-static improved model of high-speed spindle bearing was developed. And a new method for calculating the friction torque of the bearing based on the quasi-static improved model was put forward. Then the theory and experiment were validated systematically. The results show that the quasi-static improved model is correct, and the method of calculating the friction torque of high-speed spindle bearing based the quasistatic improved model is feasible and reliable.

BACKGROUND Majorities of studies explored the effect of residential built environment on psychological status, however rare studies have been conducted to reveal the real-time relationship between environment and psychological status (e.g., emotion) based on space-time approach and wearable technologies in daily life. OBJECTIVE This systematic review was conducted with the aim to explore to what extend currently we know the relationship between built environment and emotion in real time and what methodologies, methods, advanced technologies have been applied to explore this relationship. METHODS The PRISMA approach was used to guide this systematic review. The review found 286 papers based on abstract screening, of which 20 papers met the full-text selection criteria. RESULTS This review has identified various advanced technologies (i.e., global positioning system (GPS), smart phone application, electrodermal activity (EDA), electrocardiogram (ECG), electroencephalography (EEG)) used in previous real-time studies based on time-space approach to explore the built environment and emotion relationship. CONCLUSIONS The main findings and potential future directions were also discussed in the paper.

In order to solve the problem that the quasi-static model cannot calculate the friction torque of the high-speed spindle bearing, a new improved quasi-statics analysis model which can be used to calculate the friction torque of high-speed bearing was established, in which the force balance condition of ball bearing in rotary plane was added by comprehensively considering the role of the cage and the oil films. And its correctness was verified by both theory and experiment. Based on the improved quasi-static model, the friction torque which affects the internal characteristic and service performance of high-speed spindle bearing is analyzed systematically. Results indicate that the rotation speed and axial pre-load and installation are the key factors influencing the spindle bearing internal friction torque and the friction torque inside the bearing can be effectively reduced by selecting ceramic balls and more small balls structure as well as optimizing the curvature parameters of the raceway of the bearing rings, etc. In addition, the improved quasi-static analysis method provides a new and effective analysis method for the performance analysis, structural optimization design and practical application of high-speed spindle bearing.