Internal Gear Pump Tooth Profile Continuous Curvature
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Solution Overview
Problem
Conventional internal gear pumps experience noise generation due to the internal tooth meshing with external teeth formed by different curves, leading to discontinuous meshing and clearance fluctuations, which disrupt mechanical efficiency.
Innovation Solution
The internal gear pump features tooth tip and meshing sections formed by a curve with continuous curvature, where the maximum curvature is at the apex and gradually reduces towards the bottom, preventing contact over the entire circumference and smoothing meshing fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the external tooth is formed by multiple different curves (hypocycloid at tooth bottom, epicycloid at tooth tip, involute at meshing section), then the clearance between external teeth and internal teeth can be optimized at different locations, but the meshing becomes disturbed due to discontinuous curves, generating noise
Solution Approach 1:
The patent merges the tooth tip section and meshing section into a single continuous curve with one continuous curvature, eliminating the discontinuities caused by joining multiple different curves. This unified curve design maintains smooth meshing between internal and external teeth while avoiding the noise generated by abrupt curvature changes at section boundaries.
Solution Approach 2:
The patent employs a curve with continuous curvature that gradually changes from maximum at the tooth tip apex to minimum at the tooth bottom. This smooth curvature transition ensures continuous contact between mating teeth without abrupt changes, eliminating the meshing disturbances and noise that occur when discontinuous curves are joined together.
2Reliability
If the number of internal teeth is one greater than the number of external teeth, then the meshing pattern improves and clearance is optimized, but the tooth profile complexity increases making manufacturing more difficult
Solution Approach 1:
The patent defines the tooth profile using mathematical parameters (Equations 1-5) that control the continuous curvature characteristics. By adjusting parameters such as ro (reference radius), dr (variation), and θ (angular position), the tooth profile can be optimized for smooth meshing while maintaining manufacturability through standardized curve generation methods.
Data Source
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AI summary
This internal gear pump accommodates: a ring-shaped internally toothed gear provided with internal teeth, and an externally toothed gear provided with external teeth which internally mesh with the internal teeth of the internally toothed gear, said externally toothed gear being eccentrically disposed inside the internally toothed gear. The number of internal teeth is one greater than the number of external teeth. In any one of the external teeth and the internal teeth, a tooth tip section and a meshing section are formed by a curve having one continuous curvature. The curve is formed by an equation with which the maximum curvature is at the apex of the tooth tip, and the curvature gradually reduces towards the tooth bottom section.