Bearing design analysis apparatus and method
OwnerRussell D. Ide, Donald J. Paquetteinventors
Life of this patent
Estimating the term…
Abstract
A method and apparatus for designing hydrodynamic bearings having movable bearing pads and a method for supporting a rotating shaft with such bearings. Bearing pad position under load is calculated using finite element analysis to determine influence coefficients, which are then used in conjunction with a two-dimensional model of the fluid film to provide the steady-state behavior of the bearing. The bearing design is altered until an acceptable design is arrived at. A bearing designed according to this method can be used to support a rotating shaft.
Claims37
A method for designing a hydrodynamic bearing system comprising a hydrodynamic bearing for supporting a rotating shaft on a hydrodynamic fluid film, said bearing comprising a plurality of spaced bearing pads and a support structure for supporting said bearing pads, each of said bearing pads having a pad surface facing said rotating shaft, a support surface facing said support structure, a leading edge, a trailing edge and two side edges, said method comprising the steps of:
- identifying operating conditions for said hydrodynamic bearing system;
- identifying a range of acceptable steady-state behavior characteristics;
- inputting the details of a bearing construction including a pad shape and support structure configuration to support the shaft under the operating conditions;
- generating a multi-dimensional model of said bearing construction;
- translating said multi-dimensional model of said bearing construction into a system of nodes appropriate for finite element analysis;
- determining the movement characteristics of said hydrodynamic bearing construction through said finite element analysis by applying unit loads to selective nodes on said pad surface of said hydrodynamic bearing;
- forming an influence coefficient matrix from said movement characteristics;
- combining said influence coefficient matrix with a two-dimensional model of said hydrodynamic fluid film based on the Reynolds equation;
- solving said combined matrix and model in an iterative fashion to determine the steady-state behavior characteristics of said bearing construction;
- determining whether the steady-state behavior is acceptable;
- and
- modifying at least one of the pad shape and support structure if the steady-state behavior is not acceptable.
An apparatus for designing a hydrodynamic bearing system comprising a hydrodynamic bearing for supporting a rotating shaft on a hydrodynamic fluid film, said bearing comprising a plurality of spaced bearing pads and a support structure for supporting said bearing pads, each of the bearing pads having a pad surface facing said rotating shaft, a support surface facing said support structure, a leading edge, a trailing edge and two side edges, wherein operating conditions and a range of acceptable steady-state behavior characteristics have been identified for the hydrodynamic bearing system and wherein a multi-dimensional model of a bearing construction has been generated, said apparatus comprising:
- means for translating said multi-dimensional model of said bearing construction into a system of nodes appropriate for finite element analysis;
- means for determining the movement characteristics of said bearing construction through said finite element analysis by applying unit loads to selective nodes on said pad surface of said hydrodynamic bearing;
- means for forming an influence coefficient matrix from said movement characteristics;
- means for combining said influence coefficient matrix with a two-dimensional model of said hydrodynamic fluid film based on the Reynolds equation;
- means for solving said combined matrix and model in an iterative fashion to determine a steady-state behavior of said bearing construction;
- means for determining whether the steady-state behavior is acceptable;
- and
- means for modifying at least one of the pad shape and support structure in said system of nodes if the steady-state behavior is not acceptable.
A method for providing a support for a rotating shaft, the method comprising the steps of:
- providing a plurality of circumferentially spaced bearing pads, each pad having a shaft supporting face;
- providing a support structure to support the bearing pads under load and to provide for movement of the bearing pads caused by shaft rotation under load such that a hydrodynamic wedge is formed between the shaft and the pad shaft supporting faces;
- analyzing the movement characteristics of the pads and support structure under expected loading;
- and
- modifying at least one of the bearing pads and support structure to provide pad and support structure movement under load which results in the desired hydrodynamic wedge characteristics.
Dependencies are inferred from the claim text.