The multi- pad circular guide hydrostatic bearing of heavy-duty CNC machine is taken as the research object. Based on the lubrication properties of the heavy hydrostatic bearing, viscosity-temperature equation of interstitial fluid is established in various viscosities. In accordance with factory actual production, the fluid critical from laminar to turbulent is calculated by finite volume method. The inner flow field of hydrostatic bearing is simulated, when the rotating speed of workbench is 6r/min at different flow. The simulation results reveal flow distribution low and verify the reliability of the calculation. The results show that, the transition critical inlet fluid flow from laminar to turbulent of fluid in hydrostatic bearing is 22L/min. Through the above analysis and research, reveals the flow rule of the hydrostatic bearing oil film bearing gap, provides a theoretical basis for actual hydrostatic bearing for engineering structural optimization design.

Flow Criterion Research on Fluid in Hydrostatic Bearing from Laminar to Turbulent Transition

Based on computational fluid dynamics, friction lubrication theory and hydrostatic technology, large size hydrostatic Guide-way of heavy vertical CNC lathes,which are widely used, was taken as research object. The control equation of hydrostatic guide-way’s interstitial fluid was established. By finite volume method, lubricating oil properties, boundary conditions such as constant flow inlet, outlet pressure, and wall were set. The velocity distribution of hydrostatic thrust bearing’s interstitial fluid was obtained through iterative computations. And influence rules of cavity depth on interstitial oil-film of large size hydrostatic Guide-way’s was discussed. The results reflect hydrostatic bearing’s internal fluid flow state .and provide theoretical basis for the design of practical engineering hydrostatic bearing.

Relationship on Oil Cavity Depth and Oil film Flow State of the Large Size Hydrostatic Guide-way

During heavy vertical lathe working, heat caused by oil film friction and self-generated is transmitted to worktable through contact surface between oil film and worktable .That makes temperature distribution of worktable uneven and lead large thermal deformation which can affect the machining accuracy. In this article, the temperature field of worktable with reinforcing plate in different locations is simulated. Based on heat transfer theory and the actual working conditions, convective heat transfer coefficient of worktable and the initial boundary conditions are calculated. The simulation reveals the influence law of reinforcing plate arrangement on temperature distribution of worktable and the optimum position of reinforcing plate is obtained. These results provide a theoretical basis for the structural design of worktable.

http://www.sersc.org/journals/IJUNESST/vol7_no1/6.pdf

Influence of Strengthening Rib Location on Temperature Distribution of Heavy Vertical Lathe Worktable

Temperature field of sector cavity multi-pad hydrostatic thrust bearing is significantly affected by flow capacity, and different flow capacity can carry different shearing heat, so temperature field of oil film is obviously changed. For this problem, the lubrication theory and the Computational Fluid Dynamics have been used to simulate influence of flow capacity on temperature of sector cavity multi-pad hydrostatic thrust bearing, to gain relationship between inlet flow capacity and temperature of sector cavity multi-pad hydrostatic thrust bearing, achieve the optimal design of such products. Results are shown that along with the flow capacity increasing, the temperature of hydrostatic thrust bearing also becomes lower under constant rotational speed condition.

Hong Ying Li

Papers

Influence Research of Flow Capacity on Temperature Field of Hydrostatic Thrust Bearing