Ensuring accuracy in the electromechanical processing of parts holes with a high-temperature strip source

Тhe accuracy of the holes in the electro - mechanical processing with a high-temperature strip tool is achieved by the development of original tooling. The article presents technical solutions of tool and technological equipment to ensure the accuracy of holes in the implementation of processes of electromechanical processing with a high-temperature strip source. The results of measurements on cylindricality of the hole of the sleeve bearing of the upper head of the connecting rod of the Yaroslavl Engine Plant engine after volumetric electromechanical mandrel are presented, confirming the effectiveness of using the developed tooling.

A numerical analysis and experimental investigation of three oil grooves sleeve bearing performance

Purpose This paper aims to reveal the cavitation characteristics of three oil wedges sleeve bearing and set the theoretical and experimental basis for defining the oil film boundary condition. Design/methodology/approach Computational fluid dynamics model of three oil wedges sleeve bearings based on the Navier–Stokes equation is set using Fluent considering turbulent situation and two-phase flow theory. The cavitation characteristics of bearing is investigated by taking pictures of experiment. Findings The rupture region of oil film and the contours of air volume fraction increase distinctly with the increase of rotating speed and the decrease of input pressure. The critical rotating speed of cavitation occurrence and oil film pressure increases with the increase of input pressure. The change trend of experiment cavitation with the rotating speed and input pressure is consistent with theoretical cavitation in general. Originality/value The finite element model of three oil wedges sleeve bearings is established based on the Navier-Stokes calculation equation of the fluid, two-phase flow theory and turbulent model. Sleeve bearing is transparent, the pictures of cavitation can be easily taken by high-speed camera, the cavitation characteristics of bearing is studied by experiment. The cavitation performance of three oil wedges bearings is studied with the change of input pressure and rotating speed, the change trend is basically consistent for theory and experiment. The study on critical rotating speed of cavitation occurrence is benefit for defining the oil film boundary condition.

Influence of Spiral Angle on the Performance of Spiral Oil Wedge Sleeve Bearing

Spiral angel is an important structure parameter of spiral oil wedge sleeve bearing, which produces greater impact on bearing performance. Based on JFO boundary condition, the generalized Reynolds equations considering four slip conditions are established. Using the concept of partial derivatives, stiffness and damping coefficients of sleeve bearing are calculated. The results show that carrying capacity and friction drag of oil film decrease, temperature rise decreases first and then increases, and end leakage rate, stiffness, and damping coefficients generally increase first and then decrease with the increase of spiral angle. The carrying capacity, friction drag, temperature rise, stiffness, and damping coefficients are smaller and the end leakage rate is higher considering wall slip and JFO condition compared with reckoning with no slip and Reynolds boundary condition.

Dynamic and Thermal Analysis of Rotor Drop on Sleeve Type Catcher Bearings in Magnetic Bearing Systems

The catcher bearing (CB) is a crucial part of the magnetic bearing system. It can support the rotor when the magnetic bearing is shut down or malfunctioning and limit the rotor's position when large vibration occurs. The sleeve bearing has the advantages of a relatively large contact surface area, simple structure, and an easily replaced surface. There are already many applications of the sleeve type CBs in the industrial machinery supported by the magnetic bearings. Few papers though provide thorough investigations into the dynamic and thermal responses of the sleeve bearing in the role of a CB. This paper develops a coupled two-dimensional (2D) elastic deformation—heat transfer finite element model of the sleeve bearing acting as a CB. A coulomb friction model is used to model the friction force between the rotor and the sleeve bearing. The contact force and 2D temperature distribution of the sleeve bearing are obtained by numerical integration. To validate the finite element method (FEM) code developed by the author, first, the mechanical and thermal static analysis results of the sleeve bearing model are compared with the results calculated by the commercial software solidworks simulation. Second, the transient analysis numerical results are compared with the rotor drop test results in reference. Additionally, this paper explores the influences of different surface lubrication conditions, different materials on rotor-sleeve bearing's dynamic and thermal behavior. This paper lays the foundation of the fatigue life calculation of the sleeve bearing and provides the guideline for the sleeve type CB design.

Dynamic and Thermal Analysis of Rotor Drop on Sleeve Type Catcher Bearings in Magnetic Bearing Systems

The catcher bearing is a crucial part of the magnetic bearing system. It can support the rotor when the magnetic bearing is shut down or malfunctioning and limit the rotor’s position when large vibration occurs. The sleeve bearing has the advantages of a relatively large contact surface area, simple structure and an easily replaced surface. There are already many applications of the sleeve type catcher bearings in the industrial machinery supported by the magnetic bearings. Few papers though provide thorough investigations into the dynamic and thermal responses of the sleeve bearing in the role of a catcher bearing. This paper develops a coupled elastic deformation — heat transfer finite element (FEM) model of the sleeve bearing acting as a catcher bearing. The FEM model investigates the dynamic and thermal behavior when a flexible rotor drops onto the sleeve catcher bearing. The thermal load caused by the thermal expansion is also considered. The flexible rotor is composed of Timoshenko beam elements. A coulomb friction model is used to model the friction force between the rotor and the sleeve bearing surface. The contact force and 2-D temperature distribution of the sleeve bearing are obtained by numerical integration. To validate the FEM code developed by the author, firstly, both the mechanical and thermal static analysis results of the sleeve bearing model are compared with the results calculated by the commercial software, “SolidWorks Simulation”. Secondly, the transient analysis numerical results are compared with the rotor drop test results in reference 13. Additionally, this paper explores the influences of different surface lubrication conditions, different materials, such as stainless steel, bronze, and aluminum, on rotor-sleeve bearing’s dynamic and thermal behavior. This paper lays the foundation of the fatigue life calculation of the sleeve bearing and provides the guideline for the sleeve type catcher bearing design.