CN-122020912-A - Internal feedback hydrostatic bearing static performance calculation method considering internal reflux

CN122020912ACN 122020912 ACN122020912 ACN 122020912ACN-122020912-A

Abstract

The invention discloses a method for calculating the static performance of an internal feedback hydrostatic bearing by considering internal reflux, which comprises the steps of determining and inputting various basic parameters of the bearing, including structural parameters, hydraulic oil parameters and oil supply pressure parameters, and dividing grid nodes. And determining the positions of nodes corresponding to the working oil cavity, the feedback oil cavity and the oil return groove according to the structural parameters of the bearing and the number of nodes corresponding to the grid. The oil film thickness of the corresponding position of each node is calculated by utilizing the bearing structure parameters, the working oil cavity pressure and the feedback oil cavity pressure are calculated based on the flow conservation principle, the working oil cavity pressure is used as the initial oil film pressure of the oil sealing edge, and the oil film pressure distribution of the oil sealing edge is calculated by adopting a finite difference discrete Reynolds equation. Static properties including load carrying capacity and stiffness are calculated based on the pressure distribution across the oil film. According to the invention, the calculation precision of the oil cavity pressure, the oil sealing edge pressure, the bearing capacity and the oil film rigidity is improved, and the theoretical calculation and experimental performance deviation is reduced.

Inventors

WU BIN
WANG JIAN

Assignees

浙江博谷精密机械科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260401

Claims (10)

1. The internal feedback hydrostatic bearing static performance calculation method considering internal reflux is characterized by comprising the following operation steps: Determining and inputting various basic parameters of a bearing, and dividing grid nodes at the same time; The basic parameters comprise structural parameters, hydraulic oil parameters and oil supply pressure parameters; Step two, determining node positions corresponding to a working oil cavity, a feedback oil cavity, an oil supply cavity, an oil sealing edge and an oil return groove according to structural parameters of the bearing and the number of nodes corresponding to the grid; step three, calculating the thickness of an oil film at the corresponding position of each node according to the structural parameters of the bearing; Calculating the pressure of the working oil cavity and the pressure of the feedback oil cavity according to the flow conservation principle; Step five, taking the pressure of the working oil cavity as a boundary condition for calculating the oil film pressure of the oil sealing edge, and calculating the oil film pressure distribution of the oil sealing edge by adopting a finite difference discrete Reynolds equation; And step six, carrying out integral calculation on the oil film pressure based on the pressure distribution of the whole oil film, wherein the static performance comprises bearing capacity and rigidity.
2. The method for calculating the static performance of the internal feedback hydrostatic bearing considering internal reflux according to claim 1, wherein the step one of dividing the grid nodes comprises the steps of: according to the calculation precision, determining the density degree and the independence of the grids; dividing solution domains into Wherein For the number of nodes divided in the circumferential direction X of the bearing, The number of nodes divided in the bearing width direction Y.
3. The method for calculating the static performance of the internal feedback hydrostatic bearing taking into account internal reflux as claimed in claim 2, wherein the third step comprises calculating the thickness of an oil film through an initial design clearance, shaft diameter eccentricity, positioning angle and position angle under a natural coordinate system.
4. The method for calculating the static performance of the internal feedback hydrostatic bearing considering internal reflux according to claim 3, wherein the third step further comprises the step of performing flow treatment according to parallel gaps when the relative eccentricity is smaller than a set threshold after the rotor is loaded, wherein the gaps of the upper and lower oil chamber oil sealing edges comprise an oil film gap at the oil sealing edges of the upper working oil chamber and the upper feedback oil chamber and an oil film gap at the oil sealing edges of the lower working oil chamber and the lower feedback oil chamber.
5. The method for calculating the static performance of the internal feedback hydrostatic bearing taking into account internal reflux of claim 4, further comprising the following steps: Defining an upper working oil cavity, a lower working oil cavity, an upper feedback oil cavity and a lower feedback oil cavity; Calculating the flow and the oil outlet liquid resistance of the upper working oil cavity; calculating the flow and the oil outlet liquid resistance of the lower working oil cavity; calculating the flow of the upper feedback oil cavity and the lower feedback oil cavity; calculating the throttling liquid resistance of the upper feedback oil cavity and the lower feedback oil cavity; the higher order is ignored for an infinitely small amount during the calculation.
6. The method for calculating the static performance of the internal feedback hydrostatic bearing taking into account internal reflux according to claim 5, wherein only reflux between the feedback oil cavity and the working oil cavity passing through the long sealing edge of the restrictor is calculated; The flow flowing out of the lower working oil cavity is the sum of the flow flowing out of the periphery of the oil sealing edge and the flow flowing into the lower feedback oil cavity; The flow flowing out of the upper working oil cavity is the flow flowing out of the periphery of the oil sealing edge; the flow rate of the upper feedback oil cavity flowing into the upper feedback oil cavity is the difference between the flow rate of the oil supply cavity flowing into the upper feedback oil cavity and the flow rate of the upper feedback oil cavity flowing into the upper working oil cavity; the flow rate of the lower feedback oil cavity is the sum of the flow rate of the oil supply cavity and the lower feedback oil cavity.
7. The method for calculating the static performance of the internal feedback hydrostatic bearing taking into account internal reflux as set forth in claim 6, wherein the step four comprises: calculating the equivalent area of each area by utilizing the geometric dimension and the oil film thickness; And calculating the oil cavity pressure of each working oil cavity based on the calculated equivalent area and the oil supply pressure.
8. The method for calculating the static performance of the internal feedback hydrostatic bearing considering internal reflux as claimed in claim 7, wherein the equivalent area is used for reflecting the influence of the geometric shape of the oil cavity on the oil film pressure distribution of each oil cavity.
9. The method for calculating the static performance of the internal feedback hydrostatic bearing considering internal reflux according to claim 8, wherein the method further comprises the step of adopting a relaxation iteration method to calculate the oil film pressure of the edge seal, updating the initial oil film pressure value if the result is not converged, continuing iteration until the oil film pressure of the edge seal is converged, and outputting the oil film pressure distribution of the edge seal.
10. The method for calculating the static performance of the internal feedback hydrostatic bearing taking into account internal reflux as set forth in claim 9, wherein the step six comprises: Pressure field edges for oil films respectively based on oil film pressure distribution Direction integral determination Component of force in direction to The directional component force is expressed as the bearing capacity of the oil film; Will be Substituting the directional component force into dimensionless component, and calculating to obtain A dimensionless oil film component of the direction; Based on And calculating the dimensionless oil film component force in the direction to obtain the dimensionless oil film resultant force and the load angle.

Description

Internal feedback hydrostatic bearing static performance calculation method considering internal reflux Technical Field The invention relates to the technical field of bearing performance analysis, in particular to a method for calculating the static performance of an internal feedback hydrostatic bearing by considering internal reflux. Background The internal feedback hydrostatic bearing is used as an important branch of the hydrostatic bearing, and the pressure of each oil cavity can be automatically regulated according to the external load change through a special feedback oil path in the internal feedback hydrostatic bearing, so that higher static and dynamic rigidity and running stability are realized. The characteristic makes the device have irreplaceable advantages in the fields of ultra-precise machine tools, high-end measuring instruments and the like which have extreme requirements on motion precision. However, the implementation of the performance advantages is highly dependent on the precise design and analysis of complex flow fields containing internal feedback oil paths and their load carrying properties. The core of the bearing is characterized in that an internal feedback oil circuit is directly connected with different oil cavities or pressure areas to form an internal pressure self-regulating mechanism. In actual operation, lubricating oil not only flows between each oil chamber and the bearing gap, but also forms complex internal reflux between the feedback oil chamber and the working oil chamber on the same side. The back flow is strongly coupled with the bearing flow field, so that the final oil film pressure distribution, flow distribution and steady bearing performance of the bearing are fundamentally determined. The traditional method mostly adopts a traditional engineering algorithm to design and calculate the oil film pressure distribution and calculate the bearing performance by establishing a simplified physical model and deducing a static flow balance equation, and the traditional engineering algorithm is mostly adopted to design an internal feedback hydrostatic bearing so that the deviation of theoretical calculation and experimental performance is larger. And the oil sealing edge pressure and flow of the internal feedback hydrostatic bearing are calculated without adopting a mode of solving a Reynolds equation, so that calculation errors of the oil cavity pressure, flow, bearing capacity and rigidity are large. And the factor of internal backflow of each feedback oil cavity and the working oil cavity is not considered to be combined with a numerical method, so that a large deviation exists in a numerical calculation result. Meanwhile, because the internal reflux core mechanism is not accurately modeled, a designer often depends on experience or trial and error to adjust feedback oil path parameters, and high-efficiency and accurate optimization design is difficult to perform, so that the traditional engineering algorithm has obvious limitations in designing the bearing, namely the traditional engineering algorithm is approximately solved for the calculation of the pressure of the oil sealing edge of an oil cavity, and often ignores the internal reflux effect, so that the pressure distribution, the oil outlet flow, the bearing capacity, the rigidity and the like of an oil film cannot be accurately described. Disclosure of Invention The invention aims to provide a method for calculating the static performance of an internal feedback hydrostatic bearing by considering internal reflux, so as to solve the problems in the background art. The invention provides a method for calculating the static performance of an internal feedback hydrostatic bearing by considering internal reflux, which comprises the following operation steps: step one, determining and inputting various basic parameters of the bearing, and dividing grid nodes at the same time. Preferably, the basic parameters include structural parameters, hydraulic oil parameters, and oil supply pressure parameters. Preferably, the mesh node division comprises determining the degree of density of the mesh according to the calculation precision, dividing the solving domain intoWhereinThe number of nodes is divided in the circumferential direction X of the bearing,The number of nodes is divided in the bearing width direction Y. And step two, determining the positions of nodes corresponding to the working oil cavity, the feedback oil cavity, the oil supply cavity, the oil sealing edge and the oil return groove according to the structural parameters of the bearing and the number of nodes corresponding to the grid. And thirdly, calculating the thickness of the oil film at the corresponding position of each node according to the bearing structure parameters. Preferably, the oil film thickness is calculated by initially designing the gap, the shaft diameter eccentricity, the positioning angle, the position angle under a natural coordinat