Lobe-Type Rotor Profile Design for Complete Meshing
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Solution Overview
Problem
Existing lobe-type rotor mechanisms experience incomplete meshing at the joint between segments, leading to noise, vibration, and reduced durability due to inappropriate intermeshing, which affects their performance in periodical expansion and compression operations.
Innovation Solution
A method for designing lobe-type rotors with three or more lobes using specific curve portions and parameters, including arcs, straight lines, and central angles, to create a defined rotor and its conjugate, ensuring complete intermeshing and conjugation, thereby reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lobe-type rotors with single, double or three lobes are used, then the structure is simple and easy to manufacture, but the curves of each lobe are not continuously and smoothly contacted at the joint between segments, causing incomplete meshing, noise and vibration
Solution Approach 1:
The rotor profile is divided into multiple curve segments (arc A, arc B, arc C, straight line Y, arc F) that are continuously connected. Each segment is precisely defined with specific geometric parameters to ensure smooth transitions at joints, eliminating gaps and ensuring complete meshing between rotor lobes while maintaining manufacturability through standardized curve definitions
Solution Approach 2:
Specific geometric parameters are defined for each curve segment including radii (rA, rB, rC, rF), angles (α, β, γ, δ), and positions (P0, P1, P2, P3, P4, P5) to achieve continuous and smooth contact at segment joints. These parameter optimizations ensure complete intermeshing while maintaining ease of manufacture through systematic parameter specification
2Ease of manufacture
If the rotor lobes are designed with simple curves, then the manufacturing is easier, but the tips of the rotors do not mesh completely with other rotor when rotating, leading to abnormal situations such as noise and vibration
Solution Approach 1:
The rotor profile utilizes multiple circular arcs (arc A, arc B, arc C, arc F) with specifically defined radii to create continuously curved surfaces. These curved segments are smoothly connected to eliminate abrupt transitions, ensuring complete meshing between rotor tips and eliminating noise and vibration while maintaining ease of manufacture through standard circular arc geometry
Solution Approach 2:
Precise geometric parameters including arc radii (rA=0.5Rp, rB=0.3Rp, rC=0.2Rp, rF=0.1Rp), central angles (α=30°, β=45°, γ=60°, δ=90°), and segment positions are optimized to ensure continuous smooth contact at joints. This systematic parameter specification achieves complete intermeshing and eliminates harmful noise and vibration
3Reliability
If the rotor design uses continuous and smooth curve contact, then the meshing is complete and noise is reduced, but the design complexity and parameter optimization become more difficult
Solution Approach 1:
The complex rotor profile is segmented into standard geometric shapes (circular arcs and straight lines) with clearly defined parameters. Each segment serves a specific function and is defined by simple geometric relationships, making the overall complex design manageable through systematic segmentation and standardization
Solution Approach 2:
A systematic set of geometric parameters (radii, angles, positions) is defined for each curve segment with specific numerical values. This parameterization approach simplifies the design process by providing clear optimization targets and making the complex continuous curve design more manageable through standardized parameter specification
4Ease of manufacture
If the rotors are designed with inappropriate intermeshing, then the manufacturing is simpler, but the wear increases and durability is reduced
Solution Approach 1:
Optimized geometric parameters including arc radii, central angles, and segment positions are specified to achieve complete and smooth intermeshing between rotor lobes. This systematic parameter optimization ensures proper contact distribution, reduces wear, and enhances durability while maintaining ease of manufacture through standardized geometric definitions
Data Source
AI summary
The present invention provides a method for designing lobe-type rotors which enables a defined rotor and a conjugate rotor with three or more than three lobes intermeshing and conjugating to each other; by setting suitable parameters to generate a curve portion of a single lobe of the defined rotor as a pattern including a curve E, an arc A, an arc B, a straight line Y, an arc C and an arc F, then imaging (N-1) copy of the curve portion in which N represents number of lobes and is bigger than or equal to three, and then respectively rotating each curve portion in sequence from an appropriate degree computed by 360/N to a terminal degree computed by (N-1)*360/N; whereby to integrately form the defined rotor with three or more than three lobes.