Variable-Lead Screw Rotor Machining for Precise Meshing Profiles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for machining variable-lead screw pump rotors are inefficient, producing rotors with faceted or uneven surfaces and requiring complex programming, which can lead to decreased precision in meshing and increased fluid leakage due to deviations in cross-sectional thread shapes.
Innovation Solution
A method using a formed tool with adjustable parameters such as spindle angle, workpiece rotation, and center distance to machine rotors with variable lead screw threads, employing a global adjustment distribution calculated to maintain optimal clearance between meshed rotors, allowing for precise and efficient production of rotors with superior surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional turning methods are used to machine variable-lead screw rotors, then the machining process is simple to implement, but the material removal rate is slow and the surface finish is faceted or uneven
Solution Approach 1:
The patent replaces conventional turning operations with a forming process using a specially designed tool. Instead of removing material layer by layer through cutting, the forming tool directly shapes the variable-lead screw thread by plastic deformation or displacement, significantly increasing material removal rate while producing a superior surface finish without faceting.
Solution Approach 2:
The patent employs a forming tool with specific geometric parameters designed to match the desired variable-lead screw profile. By changing the tool's forming parameters (geometry, position, and movement characteristics), the process achieves both high productivity and precise surface finish quality that conventional turning cannot provide.
2Manufacturing precision
If multiple complex passes are used to vary the lead during machining, then the variable-lead thread can be produced, but the CNC programming becomes computationally complex and error-prone
Solution Approach 1:
The patent pre-configures the forming tool with the exact geometry of the desired variable-lead screw thread. All the complexity of varying the lead is built into the tool's design and setup before machining begins, rather than requiring complex real-time CNC programming during the machining process. This eliminates computational complexity while maintaining precision.
3Productivity
If formed tools are used to machine the thread, then the machining speed increases, but the cross-sectional shape of the thread deviates from the desired profile
Solution Approach 1:
The patent carefully controls the forming tool's geometric parameters, position, and movement characteristics during the forming process. By optimizing these parameters, the process achieves high machining speed while maintaining accurate thread cross-sectional shape, eliminating the deviation problem that plagues conventional forming methods.
4Productivity
If the cross-sectional shape of the thread deviates, then the machining process is simpler and faster, but the meshing precision between rotors decreases and fluid leakage increases
Solution Approach 1:
The patent optimizes the forming tool parameters and process conditions to produce thread cross-sectional shapes that closely match the desired profile. This ensures high meshing precision between rotors and minimal fluid leakage, while maintaining the productivity benefits of forming operations.
Data Source
Figure 1
Figure 2a~2e
Figure 3
AI summary
A method of machining, with a formed tool, a first rotor and a second rotor with mutually complementary meshing threads involves rotating a first workpiece about a longitudinal axis of the workpiece. The tool makes one or more passes along the longitudinal axis of the workpiece as the workpiece rotates so as to remove material, thereby forming the flanks of each helix of the first rotor's thread. The value of at least one of the parameters that collectively define the relative position and relative movement of the workpiece and formed tool is varied during each pass so as to vary the lead of the thread. The above steps are repeated for a second workpiece, thereby forming the second rotor. Adjustments are made to at least one of said parameters during one or more of the passes in order to maintain mutually complementary shapes of the threads of the rotors.