Development of auto loading device in bearing positioning lip stamping

With the continuous development of our economy, the types and quantity of engine bearing are increasing. In order to prevent the bearing moving in the bearing pedestal, one or both ends of the bearing need to make positioning lip for axial positioning. In order to meet the needs of mass bearing production, an auto loading device for positioning lip of bearing is proposed in this paper. The horizontal conveyor belt and loading guide are used to make the blank turn to the required angle, and then the double cylinder valve and push rod motor are used to realize the time-sharing conveying and continuous loading of the blank. During the loading process, there are inclined slideway and blocking plate to avoid the collision between blanks and ensure the reliable loading bearings. Through the actual production verification, the developed device has the advantages of simple structure, low cost, fine working stability, and made great improving in the efficiency and safety for production of bearing.

Study on Lubrication Efficiency and Friction Power Loss of Engine Based on a Hybrid Hydrodynamic Model

Friction loss is one of the main factors affecting engine power. Reducing friction power losses to improve the power of engines is a significant concern for designers. Especially, under the background of energy-saving and emission reduction, it is indispensable to carry out an in-depth investigation on engine bearing lubrication characteristics. Unlike the previous studies of separate modelling, a new modelling method of coupling the dynamic and lubrication model is proposed in this paper. The bearing capacity, friction force, friction coefficient and eccentricity ratio were taken as the evaluation criterion, and the influence of design parameters such as angular speed, bearing radius and width on the lubrication efficiency and friction power loss (LE-FPL) were studied. The results indicate that increasing the angular speed, bearing radius or width can effectively reduce the eccentricity ratio and raise the minimum oil film thickness, which is beneficial to improve the lubrication efficiency. However, the above methods to improve engine lubrication efficiency will lead to more power loss of engine to a certain extent. Therefore, studies on reducing the friction power loss for the engine and on improving the lubrication efficiency for the engine should be considered coordinately in the dynamic design and optimisation of the engine.

Study of Oil Film Heat Transfer in Gas Turbine Engine Bearing Chamber

A clear understanding of the heat transfer processes in a gas turbine engine bearing chamber at the design stage makes it possible to properly design the lubrication and sealing systems and ensure the future bearing safe operation. The heat transfer coefficient (HTC) calculated based on the classical Newton-Richman equation is widely used to represent the heat transfer data and useful for the thermal resistance analysis. However, this approach is only formally applicable in the case of a two-phase medium. While there is a need to model a two-phase medium, setting the flow core temperature correctly in the Newton-Richman equation is an issue that is analyzed in this study. The heat from the flow core is transferred to the boundary of the oil film on the bearing chamber walls by an adjacent air and precipitating droplets. The analysis showed that droplet deposition plays a decisive role in this process and significantly intensifies the heat transfer. The main contribution to the thermal resistance of internal heat transfer is provided by the oil film. In this regard, the study considers the issues of the bearing chamber workflow modeling allowing to determine the hydrodynamic parameters of the oil film taking into account air and oil flow rates and shaft revolutions. The study also considers a possibility to apply the thermohydraulic analogy methods for the oil film thermal resistance determination. The study presents practical recommendations for process modeling in the bearing chamber.

Numerical Simulation of the Oil Droplet Size Distribution Considering Coalescence and Breakup in Aero-Engine Bearing Chamber

In order to improve the inadequacy of the current research on oil droplet size distribution in aero-engine bearing chamber, the influence of oil droplet size distribution with the oil droplets coalescence and breakup is analyzed by using the computational fluid dynamics-population balance model (CFD-PBM). The Euler–Euler equation and population balance equation are solved in Fluent software. The distribution of the gas phase velocity field and the volume fraction of different oil droplet diameter at different time are obtained in the bearing chamber. Then, the influence of different initial oil droplet diameter, air, and oil mass flow on oil droplet size distribution is discussed. The result of numerical analysis is compared with the experiment in the literature to verify the feasibility and validity. The main results provide the following conclusions. At the initial stage, the coalescence of oil droplets plays a dominant role. Then, the breakup of larger diameter oil droplet appears. Finally, the oil droplet size distribution tends to be stable. The coalescence and breakup of oil droplet increases with the initial diameter of oil droplet and the air mass flow increasing, and the oil droplet size distribution changes significantly. With the oil mass flow increasing, the coalescence and breakup of oil droplet has little change and the variation of oil droplet size distribution is not obvious.