A Dynamics Study On The Anti-rotation Mechanism With The Ball In The Scroll Compressor And Its Reliability Evaluation

As the third generation of new compressor, scroll compressor has some advantages like high efficiency, small size, simple structure, stable and reliable operation and so on. It is widely used in refrigeration, power engineering, and transportation field. The main working parts of scroll compressor includes dynamic and static vortex plate, the dynamic vortex disk and static vortex disk, crankshaft connecting rod journal, and various types of anti-rotation mechanism, etc. The structure and working principle of anti-rotation mechanism with the ball is similar to the ball bearing’s, so its mechanical principle can be applied in the thesis to analyze the stress of the ball in order to establish a balance equation of the force and moment. Then based on the analysis of the deformation and stress of the ball in different times, a graph of deformation and stress can be drawn by the finite element software ANSYS.In the process of the eccentric circular motion, the ball itself also does the rotation movement around the symmetric centerline. Besides, the movement mechanism of anti-rotation mechanism with the ball is the parallelogram principle. Thus, according to the mechanical characteristics of ball, in addition to the force model equation, the model of a single ball and action guide can also be respectively established. The nephogram of deformation and stress of the ball is drawn by ANSYS. Based on the nephogram, after the finite element analysis of the whole organization model, the biggest deformation and stress of ball can be analyzed. Finally with the calculation, the intension of the ball is checked and the steady operation time of the ball is concluded by the life calculation to ensure the rationality and reliability of ball design.The study on the crankshaft is mainly from two aspects: establishing the balance equation; according to the established model, analyzing the distribution of deformation and stress of crankshaft by the finite element software ANSYS. After the above steps, Mini-crank’s intensity is checked by the results distribution. Finally, combining with the comprehensive analysis of the safety coefficient of Mini-crank, its reliability evaluation can be ensured.A fault tree analysis model of ball mechanism in scroll compressor is established in this study. Besides an effectiveness factor table is drawn according to the detailed description of major types of faults of ball mechanism. Moreover, based on the principles of safety system engineering, several different types of reliability evaluation method and theory at home and abroad are compared and analyzed. Then the reliability evaluation model of scroll compressor is built by the quantitative evaluation of subsystem. At last, according to the studies on the reliability evaluation and combining with domestic and foreign advanced reliability evaluation experience, the optimization method and evaluation process of scroll compressor are put forward.