Design Of Rotary Pressure Chamber And Characteristics Study On Hydrostatic Bearing For Rock Mechanics Testing Machine

Rock mechanics testing machine is a device in laboratory to reappear and study various mechanical properties of the rock sample under the coupling impact caused by the force, liquid and gas vadose in the deep Earth’s interior. In order to visualize the fracture process of rock sample, geologists hope to use a testing machine with rotatable pressure chamber, and high energy accelerator CT imaging and3-d image reconstruction technology, to observe the conditions and characteristics of rock burst, and to provide new basis of underground oil and gas mining, and earthquake research etc.In order to make the pressure chamber in rock mechanics testing machine rotates precisely, both sides the pressure chamber need bearings. Overall design of rock mechanics testing machine was designed, the drive mode of pressure chamber and rotate mode was discussed. Prototype machine was made and tested. The feasibility of this design was validated.From the experimental study and simulation of the gears, the friction torque influenced rotating precision significantly was found. Hydrostatic bearing applied in rock mechanics testing machine was proposed in this thesis. This thesis discussed the driving scheme of the turntable pressure chamber. Advantages of several kinds of pressure chamber turntable supporting schemes were compared. A hydrostatic bearing was designed with axial load of0-2000kN. Hydrostatic bearing improved the smooth rotation of the pressure chamber, and decreased the friction torque from1152Nm to2.12Nm. This friction reduction improved control system of the drive significantly.After finishing the design of hydrostatic bearing, static and dynamic characteristics of the hydrostatic bearing were studied. Flow equations, the bearing capacity of the static characteristic equations, stiffness equations were established on the basis of fluid dynamics. The influence of oil film thickness, the oil cavity size and depth of oil cavity on the hydrostatic bearing capacity and stiffness was also discussed. The bearing capacity of the dynamic characteristic equation was established. Dynamic characteristics of hydrostatic bearing, influenced by volume of oil, the oil film thickness, initial oil film pressure and oil viscosity were also simulated.Simulation shows that the pressure chamber adopts static pressure support, rock mechanics testing machine rotates with lower bounce than those of rolling bearings. Meanwhile, the lower friction torque improved the smooth degree of the rotation, and meets the requirements of clear imaging. Simulation studies on static and dynamic characteristics also supplied the design basis of the hydrostatic bearing.Thesis research provides an important basis for design of the rock testing machine, and enriched hydrostatic bearing technology.