CN110083924A - Film lubrication performance simulation method under hydrostatic thrust bearing unbalance loading operating condition - Google Patents

Abstract

Oil film performance simulation method under hydrostatic thrust bearing unbalance loading operating condition, the invention mainly relates to the analogy methods of film lubrication performance under double square chamber hydrostatic thrust bearing unbalance loading operating condition.The invention solves hydrostatic thrust bearings under unbalance loading operating condition without actually active method come the problem of simulating film lubrication performance.This method is to pass through: 1, establishing 6 symmetrical double square lubricating pad models by UG；2, model is imported in ANSYS ICEM CFD software, creates Fuel film model part, create topological structure partition structure grid；3, check whether the Points And lines of model are all associated with the point of block with line；4, grid division number of nodes, the encryption of oil inlet number of nodes；5, boundary film condition is set in ANSYS CFX software；6, convergence uses the standard of ANSYS CFX software default, judges whether fluctuation is stable.The present invention is applied to greasy property simulation field under hydrostatic thrust bearing unbalance loading operating condition.

Description

Simulation method for oil film lubrication performance of hydrostatic thrust bearing under eccentric load condition

technical field

The invention relates to a method for simulating the lubricating performance of an oil film of a static pressure thrust bearing, in particular to a method for simulating the lubricating performance of an oil film when double rectangular cavities are eccentrically loaded.

Background technique

Hydrostatic thrust bearing is one of the core components of heavy-duty CNC machining equipment. The better its performance, the higher the processing quality and operating efficiency of the equipment. In an ideal state, the center of mass of the workpiece should be at the center of the rotary table to carry the center load. At this time, the working state of the hydrostatic thrust bearing is in the best performance state. However, in the actual processing process, the center of mass of the workpiece may not be in the center of the rotary table, and there will be an eccentric load, which will locally thin the oil film of the hydrostatic thrust bearing, and even cause dry friction, which will lead to the failure of the hydrostatic thrust bearing. This problem restricts With the development of my country's heavy-duty CNC processing equipment in the direction of high precision and high efficiency. However, there are few domestic and foreign researches on the simulation methods for the oil film lubrication performance of hydrostatic thrust bearings under eccentric load conditions. It provides a basis for further optimization design of thrust bearings.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem that during the actual working process of the static pressure thrust bearing, the center of mass of the workpiece and the center of rotation of the rotary table do not coincide, and the eccentric load occurs, and the thickness of the oil film becomes uneven, resulting in a significant decrease in the lubricating performance of the static pressure thrust bearing Even dry friction occurs, lacking an effective method to simulate this phenomenon. In order to explore the lubricating performance of oil film of hydrostatic thrust bearing under eccentric load, a simulation method of oil film lubricating performance of hydrostatic thrust bearing under eccentric load was proposed.

The simulation method of the lubricating performance of the hydrostatic thrust bearing under eccentric load is realized through the following technical scheme.

(1), through the UG three-dimensional modeling software to establish six symmetrical two-rectangular oil pad three-dimensional models;

(2) Import the model into the ANSYS ICEM CFD software, split the required surfaces, create the oil film model part, and create the topological structure to divide the structural mesh;

(3) Check whether the points and lines of the model are all connected with the points and lines of the block. If all the lines of the block are all green, all are connected, otherwise they are not all connected, so you need to re-connect according to the above steps;

(4) The number of grid nodes is divided; the number of oil inlet nodes is encrypted, and the number of adjacent nodes is not more than twice, so as to ensure the quality of the grid;

(5) Set boundary oil film conditions in ANSYS CFX software, including the setting of viscosity-temperature relationship and domain setting;

(6) Convergence adopts the default standard of ANSYS CFX software, that is, the residual value is lower than 10 ^-4 , to judge whether the fluctuation is stable or not, and whether there is an obvious downward trend.

The invention can use a computer to simulate the actual working condition of the static pressure thrust bearing when the workpiece is eccentrically loaded, and obtain the oil film lubrication parameters of the static pressure thrust bearing under different eccentric load degrees. This method can save a lot of time and obtain the oil film lubrication parameters consistent with the experimental results. By studying the lubricating oil film parameters, the influence of different eccentric loads on the lubricating properties of the oil film is revealed. This provides an effective reference for further optimization research on hydrostatic thrust bearings, and also lays a solid foundation for heavy equipment using hydrostatic thrust bearings to achieve high efficiency and high precision.

Description of drawings

Fig. 1 is a flow chart of the simulation method for oil film lubrication performance of hydrostatic thrust bearing under eccentric load conditions.

Figure 2 is the oil film model under the eccentric load condition mentioned in step A.

Figure 3 is the list after defining Part mentioned in step B1.

Fig. 4 is a diagram of the oil film grid topology model mentioned in step B2.

Fig. 5 is a grid division diagram of the oil film mentioned in step C.

Fig. 6 is a schematic diagram of the oil film grid quality mentioned in step D.

Fig. 7 is the position setting of the oil film mentioned in step E.

Fig. 8 is a graph of the iterative residual error mentioned in step F.

Detailed ways

It can be achieved through the following technical solutions,

Step A: Use UG software to model the oil pad under partial load conditions, and create models of different shapes and sizes according to different conditions.

Step B1: Use UG software to export the established oil film models under different working conditions as .x.t files, and import the exported .x.t files into ANSYS ICEM CFD software, and set the unit to mm; because CFD software cannot The surface of the oil film is automatically divided into two surfaces, so after the model is imported, the first thing to do is to split the surface in UG into the required surface; the second is to create the part of the oil film model. This step is mainly for the boundary conditions after importing CFX. Setting, part setting has IN1, IN2, OUT1, OUT2, OUT3, OUT4, INTERFACE1, INTERFACE 2, ROTATE, WALL these definition surfaces.

Step B2: Create a topological structure When dividing the structural grid, a top-down division method is adopted. First click the option Blocking, select the Check Block option, select the sub-topology structure in the split block, first divide the X direction block, and then divide the Y and Z direction blocks to delete unnecessary topology structures. When creating point mapping, each vertex of the 3D model is mapped to the vertex of the block in turn. For line mapping, you can directly select the Auto association option in Blocking to complete the mapping of oil film and oil cavity points and lines.

Step B3: The shape of the oil inlet is cylindrical, so the grid should use an O-shaped grid to divide its block separately. First, add two points to the circularly symmetrical part to divide the block in the X and Y directions. Then select the Check Block option to stretch out the rectangular block below to obtain a block in the shape of a cuboid. When mapping, map the quadrilateral to the circle. Finally, click the Select face option in the Split Block, select the upper and lower sides of the cylinder, and click OK to complete all block division and point-line mapping.

Step C: Check whether the points and lines of the model are all associated with the points and lines of the block, hide the points and edges under Geometry, and check whether the lines of the block are all green. If yes, connect all of them; if something is not green, it means that there is no connection here, so you need to re-connect according to the above steps.

Step D: Click the Mesh Quality module to check the quality of the oil film mesh and angle mesh. Use Output/Select Solver to select the ANSYS CFX solver when outputting the grid, and the default output file format is .CFX5.

Step E1: Select ANSYS CFX software to simulate and analyze the oil film. Set the fluid domain as FLUID, select the material as 32# lubricating oil, select the fluid calculation model as total energy, set the temperature as 293K, and keep the default settings for other settings.

Step E2: Setting of the oil inlet Inlet. Set the flow rate of inlets IN1 and IN2 to 0.035, and set the temperature as room temperature 293K, that is, 20°C.

Step E3: Setting of the oil outlet Outlet, set four oil outlets, respectively OUT1, OUT2, OUT3, OUT4, and the relative atmospheric pressure is 0Pa.

Step E4: Click Interface, select Fluid for Interface Type, select INTERFACE1 for Interface side1, select INTERFACE2 for Iterfance side2, and set the Rtation Axis rotation axis to the Z axis. Select the GGI grid splicing method and periodic axis in the Mesh connection option The radial tolerance is 0.0001.

Step E5: Setting of the wall wall, the upper surface of the oil film is the rotating working surface, which is set as Rotate Wall, and the surface of the lower surface of the oil film in contact with the oil pad and the inner wall of the oil chamber are both set as Wall.

Step E6: ROTATE setting: Select Rotating Wall for the Option option, rotate to rotate axis, select Z-axis global Z, set the rotation speed of the rotary table around the Z-axis to 100r/min, and complete the setting of the oil film boundary conditions.

Step F: The convergence standard adopted is the default standard of ANSYS CFX software, that is, the residual value is already lower than 10 ^-4 , and the fluctuation is stable without obvious downward trend.

Claims (1)

1. the analogy method of film lubrication performance under hydrostatic thrust bearing unbalance loading operating condition, it is characterised in that hydrostatic thrust bearing unbalance loading Operating condition Imitating method is realized according to the following steps:

Step A: the lubricating pad under unbalance loading operating condition is modeled using UG software, is created that different shape size according to different operating conditions Model；

Step B1: exporting as .x.t file for the Fuel film model under established different operating conditions using UG software, will be derived .x.t file is imported into ANSYS ICEM CFD software, setting unit mm；The face that can not will be established in UG due to CFD software Automatically two faces are divided into, so what is done first after model importing is that the face in UG is split as required face；Followed by Create the part of Fuel film model, the step for be setting in order to import CFX back boundary condition, part be set with IN1, IN2, OUT1, OUT2, OUT3, OUT4, INTERFACE1, INTERFACE 2, these definition faces ROTATE, WALL；

Step B2: top-down division methods are used when creation topological structure partition structure grid, first click on option Blocking selects Check Block option, selects the subtopology structure in split block, first draws to X-direction block Point, then Y, Z-direction block are divided, unnecessary topological structure is deleted, when creation point maps, by each top of threedimensional model Point is successively mapped in the vertex of block, and the Auto association that line mapping can directly select in Blocking is closed automatically Join option, completes the mapping of oil film and oil pocket Points And lines；

Step B3: the shape of oil inlet is cylinder, then grid should use O-shaped grid, individually be divided to its block, first Two points are dosed at the symmetrical position of circle, the block of X, Y-direction is divided, then select Check Block option will under The rectangular block in face it is stretched come, and then obtain the block of rectangular shape, when mapping, quadrangle be mapped to circle, most The Select face option in Split Block is clicked afterwards, selects the top and bottom of cylinder, is clicked and is determined, so far completes all Block is divided and dotted line mapping；

Step C: checking whether the Points And lines of model are all associated with the Points And lines of block, by under Geometry point and Edge hides, and checks whether the line of block is all green, if it is, all in association；If somewhere is not green , show in no association herein, therefore need to be associated again by above-mentioned steps；

Step D: clicking Mesh Quality module, check oil film grid and angle mesh quality, adopts when exporting grid ANSYS CFX solver is selected with Output/Select Solver, default output file format is .CFX5；

Step E1: selection ANSYS CFX software carries out simulation analysis to oil film, sets fluid domain as FLUID, selects material For 32# lubricating oil, fluid calculation model is selected as total energy, temperature setting 293K, other settings keep default Setting；

Step E2: the setting of oil inlet Inlet, the flow of inlet porting IN1 and IN2 are 0.035, and temperature is given as room temperature 293K I.e. 20 DEG C；

Step E3: four oil outlets, respectively OUT1, OUT2, OUT3, OUT4 are arranged in the setting of oil outlet Outlet, relatively large Air pressure is 0Pa；

Step E4: clicking Interface, and Interface Type selects Fluid, the choosing of interface Interface side1 option INTERFACE1 is selected, interface Iterfance side2 selects option INTERFACE2, and Rtation Axis rotary shaft is Z axis, GGI grid connecting method is selected in Mesh connecion option, periodical axial-radial tolerance is 0.0001；

Step E5: the setting of wall surface Wall, oil film upper surface are rotating face, are set as Rotate Wall, oil film lower surface The face and oil pocket inner wall being in contact with lubricating pad are both configured to Wall；

The setting of step E6:ROTATE: Option option selects Rotating Wall, rotates to rotate axis selection Z axis Global Z, revolving speed is 100r/min to setting rotary table about the z axis, completes the setting of Oil Boundary condition；

Step F: the convergence of use is the standard of ANSYS CFX software default, i.e., residual values are already below 10^-4, and wave Emotionally condition is stablized, without apparent downward trend.