Rotating machines

Abstract

A method of computer aided engineering for designing a rotating machine assembly involves creating within a graphical user interface of a computer system a layout of the rotating machine assembly, and forming a functional model of the rotating machine assembly from the layout. The layout is created by selecting and positioning components for the rotating machine assembly, and then creating associations between them. The functional model is based on one or more of the associations, relative positions of the selected components, properties of the selected components and properties of the associations.

1 . A method of computer aided engineering for designing a rotating machine assembly, the method comprising the steps of:
 creating within a graphical user interface of a computer system a layout of said rotating machine assembly according to the steps of:
 receiving a user selection of components for said rotating machine; 
 positioning said selected components; 
 creating associations between said selected components; and 
   forming a functional model of said rotating machine assembly from said layout based on one or more of said associations, relative positions of said selected components, properties of said selected components and properties of said associations.   
     
     
         2 . A method according to  claim 1 , comprising the step of:
 predicting a performance of said rotating machine assembly;   wherein said step of predicting said performance comprises predicting within said graphical user interface, linking to an integrated user interface, or exporting data to one or more CAD/CAE packages.   
     
     
         3 . A method according to  claim 2 , in which said step of predicting comprises one or more of the steps of:
 reporting said performance of said rotating machine assembly;   reporting a power flow through said rotating machine assembly or said selected components;   reporting a gear sizing;   reporting a gear torque capacity and centre distance safety factor;   reporting a packaging space;   reporting bearing loads;   reporting a suitable dynamic load factor corresponding to a minimum required dynamic capacity of a roller bearing; and/or   reporting a load on a housing or casing;   reporting a weight of the components and assembly;   reporting an estimate of the cost   
     
     
         4 . A method according to  claim 3 , comprising the step of modifying the model to achieve increasing product performance according to one or more of the steps of:
 modifying said layout; according to the steps of:
 receiving a user selection of one or more new or existing components for said rotating machine; 
 positioning said selected new or existing components; 
 creating associations between said selected new or existing components; and 
 updating said functional model; 
   modifying one or more of said properties according to the steps of:
 receiving a user selection of a component or association; 
 setting or modifying a property of said selected component or of said selected association according to a user request; and 
 updating said functional model; 
   and executing a number of times said step of forming an increasingly complex functional model.   
     
     
         5 . A method according to  claim 4 , wherein said step of modifying a property comprises a click-and-drag action. 
     
     
         6 . A method according to  claim 4 , wherein said selected component is a gear set and said property is a gear ratio, said step of modifying said gear ratio automatically modifying diameters of the corresponding gears without any need for further user interaction. 
     
     
         7 . A method according to  claim 5 , wherein said selected component is a shaft or assembly of concentric shafts and said property is its radial distance to other parallel shafts which define the centre distances of the gear sets mounted on the shafts, said step of modifying said centre distances automatically modifying diameters of the corresponding gears without any need for further user interaction. 
     
     
         8 . A method according to  claim 4 , said selected component is a gear and said property is a face width, said step of modifying said face width automatically modifying packaging space or torque capacity of said gear without any need for further user interaction. 
     
     
         9 . A method according to  claim 4 , wherein said component is a shaft having steps formed therein to allow different outer diameters to be applied to different sections and said property is an outer diameter of said shaft, said step of modifying said outer diameter automatically modifying an inner diameter of said shaft so as to maintain a relationship between the inner and outer diameters without any need for further user interaction. 
     
     
         10 . A method according to  claim 9 , wherein when an inner diameter of one section becomes greater than an outer diameter of an adjacent section, said step of modifying defining two steps, separated axially by a default thickness between said inner and said outer diameters of said shaft and acting as a transition between said shaft sections; wherein creation and manipulation of said transitional step is performed automatically. 
     
     
         11 . A method according to  claim 4 , wherein said selected component is a Ravigneaux planetary gear set in which each planet set of said Ravigneaux is either a plus-planet or minus-planet and said property is a gear ratio sign, wherein said step of modifying said Ravigneaux comprises selecting the ratio sign of the gear set. 
     
     
         12 . A method according to  claim 3 , wherein the step of the reporting is reporting a gear torque capacity and safety factor, in which the gear torque capacity is calculated using the properties:
 centre distance or pinion diameter;   centre distance or pinion diameter and face width;   centre distance or pinion diameter, face width and gear ratio; or   ring gear (or sun gear) diameter, face width and ratio;   and a respective constant kn, where n=1 to 4;   
       and the recommended centre distance or ring gear diameter is calculated using the properties:
 torque and ratio; 
 torque, face width and gear ratio; or 
 torque, face width and ratio; 
 and a respective constant kn, where n=1 to 4. 
 
     
     
         13 . A method according to  claim 1 , wherein said components include gears, gear sets, epicyclic gear sets, Ravigneaux planetary gear sets, hypoid gears, spiral bevel gears, skew gears, face gears generators, motors, rotors, stators, clutches, shafts pumps, turbines or bearings. 
     
     
         14 . A method according to  claim 13 , wherein said component is a simple shaft support bearing and comprises no user-defined information on the radial, axial or tilt stiffness. 
     
     
         15 . A method according to  claim 1 , wherein the model is modified so as to provide increased model complexity and its performance is assessed using analysis methods that are increasingly complex. 
     
     
         16 . A method according to  claim 1 , comprising the step of displaying within said graphical user interface a representation of said layout, said representation including a schematic diagram, an orthogonal diagram, a profile diagram or a stick model, and wherein said representation is interchangeable between said schematic diagram, orthogonal, profile diagram or stick model. 
     
     
         17 . A method according to  claim 1 , wherein the rotating machine assembly includes gear-boxes, drive trains, transmissions, electric motors, generators, pumps, and turbines. 
     
     
         18 . A method according to  claim 4 , including the step of: setting a first limit value for a property;
 setting a second limit value for a property;   setting a step function;   varying a value of a property between said first limit value and said second limit value according to the step function;   predicting a function and/or a performance of said rotating machine assembly at each value; and   reporting said function and/or said performance of said rotating machine assembly at each value.   
     
     
         19 . A computer readable product for computer-aided engineering design of a rotating machine assembly, the product comprising code means designed for implementing the steps of the method according to  claim 1 . 
     
     
         20 . A computer system for computer-aided engineering design of a rotating machine assembly, the system comprising means designed for implementing the steps of the method according to  claim 1 .