Helical Rotor Eccentric Cycloidal Profile for High-Speed Pumping
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Solution Overview
Problem
Helical rotary machines experience high friction losses, reduced durability, and limited rotor rotation speed due to slippage and power contact between rotors, which restricts their efficiency and suitability for various media applications.
Innovation Solution
The implementation of an eccentrically cycloidal (EC) engagement between helical rotors with one rotor having teeth profiles generated by convex segments of a cycloidal curve and the other by arcs of circles eccentrically offset from the rotor axis, providing a direct and leak-resistant power contact that minimizes slippage and enhances manufacturing tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cycloidal teeth with slotted clearance are used to provide leak resistance, then leak resistance is improved, but rotor slippage increases causing friction losses and reduced durability
Solution Approach 1:
The invention changes the geometric parameters of the tooth profiles from traditional cycloidal shapes with slotted clearance to eccentrically cycloidal profiles where the generating circle is offset from the rotor axis. This parameter change eliminates the slotted clearance while maintaining leak resistance through continuous line contact between teeth, thereby reducing slippage and friction losses.
Solution Approach 2:
The invention uses curved profiles generated by eccentric circles instead of straight or traditional cycloidal lines. The eccentric circular generation creates smooth, continuous curved surfaces that ensure line contact between rotating teeth, eliminating the harmful slotted clearance regions present in traditional cycloidal designs.
2Reliability
If tight contact between rotors is provided to prevent leakage, then leak resistance is improved, but friction forces increase decreasing pump efficiency
Solution Approach 1:
The invention optimizes the contact parameters by using eccentric circular generation with specific radius ratios and offset distances. This creates tight leak-resistant contact while controlling the contact area and pressure distribution to minimize friction forces and maintain high pump efficiency.
Solution Approach 2:
The eccentric cycloidal profile creates localized optimal contact zones where leak resistance is maximized, while other regions maintain reduced contact pressure. This local optimization of contact quality ensures leak prevention at critical points without creating excessive friction across the entire tooth surface.
3Power
If synchronizing pinions are added to transmit torque between rotors, then torque transmission is improved, but overall dimensions increase and layout becomes complicated
Solution Approach 1:
The invention merges the torque transmission function directly into the tooth engagement interface of the rotors themselves. The eccentric cycloidal teeth are designed to transmit torque through their line contact, eliminating the need for separate synchronizing pinions and simplifying the overall device layout while maintaining effective torque transmission.
Solution Approach 2:
The invention extracts the torque transmission function from the auxiliary synchronizing pinion system and integrates it directly into the primary rotor tooth engagement. This extraction eliminates unnecessary components and simplifies the mechanical layout while maintaining the essential torque transmission capability.
4Speed
If rotor rotation speed is increased to reduce dimensions and weight, then compactness is improved, but slippage and power contact cause cavitation limiting maximum speed
Solution Approach 1:
The invention changes the tooth profile parameters to eccentric cycloidal shapes that eliminate slippage and ensure pure rolling contact. This parameter change prevents cavitation by maintaining consistent contact pressure and velocity relationships, enabling higher rotor rotation speeds without the cavitation limitations of traditional cycloidal designs.
Solution Approach 2:
The use of eccentric circular generation creates smooth curved tooth surfaces that ensure continuous line contact and pure rolling motion. This curvature-based design eliminates the velocity differences and slippage that cause cavitation, allowing the rotors to operate at higher speeds reliably.
Data Source
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AI summary
The invention relates to the field of rotary positive displacement machines capable of acting as an engine and as a pump, and relates to improving the profile of working members of helical rotary engines, compressors and pumps. An actuator is comprised of a pair of rotors (1, 2) having engaged helical teeth (8, 11). The rotors are disposed in chambers (6, 7) which encircle both. The working areas of the profiles of the teeth (11) in an engaged pair are delineated in cross-section by portions (12) of a cycloidal curve (13) for one rotor and by arcs (9) of circumferences (10) which are eccentrically offset from the axis of the second rotor. Such a profile of teeth produces an eccentrically cycloidal engagement capable to work efficiently at very high rotor rotation speeds. The presence of power contact and low sensitivity to gearwheel skews allow for working with nonhomogeneous media, including those containing solid inclusions.