Toothed Belt Sprocket Interference Fit Wear Reduction
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Solution Overview
Problem
The existing toothed belt and sprocket systems experience undue wear and vibration due to chordal action, which increases land pressure and leads to premature failure, as the belt pitch line becomes chordal over the pulley groove, causing uneven support distribution and increased wear on the belt land.
Innovation Solution
A belt and sprocket system with a truncated tooth tip forming a reservoir between the tooth and sprocket groove, achieving an interference fit that reduces land pressure by shifting support from the belt land to the tooth flank and groove, while maintaining adequate support through a non-locking wedge form and fluid accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the belt tooth tip engages the bottom of the pulley groove with clearance, then the belt can accommodate shrinkage and manufacturing tolerances, but the pitch line becomes chordal over the pulley groove causing undue wear in the land portion of the belt
Solution Approach 1:
The invention applies local quality by creating a truncated tooth tip with a specific geometry that concentrates engagement at a localized region. The tooth tip is truncated at an angle between 30-60 degrees, creating a small contact area at the groove bottom that prevents chordal action while maintaining overall belt flexibility and accommodation of shrinkage.
Solution Approach 2:
Instead of designing the tooth to engage the groove with clearance at the bottom (conventional approach), the invention inverts the approach by truncating the tooth tip to engage the groove bottom directly. This reversal of the engagement geometry eliminates the chordal action problem while still allowing for manufacturing tolerances and shrinkage through the truncated geometry.
2Object-affected harmful factors
If the belt tooth engages the sprocket groove with interference fit, then land pressure is reduced and wear is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the geometric parameters of the tooth tip by truncating it at a specific angle (30-60 degrees) and creating a controlled interference fit. This parameter modification allows the tooth to engage the groove with sufficient precision to reduce land pressure while the truncated geometry provides tolerance for manufacturing variations and material shrinkage.
3Adaptability or versatility
If the pitch line becomes chordal over the pulley groove, then the belt can accommodate manufacturing tolerances, but vibration increases due to cogging action
Solution Approach 1:
The truncated tooth tip creates a localized engagement point at the groove bottom that prevents the pitch line from becoming chordal. This localized engagement maintains belt adaptability to tolerances while eliminating the vibration-causing cogging action that occurs when the pitch line spans across the groove.
Data Source
AI summary
A belt and sprocket system comprising a tensile cord disposed within a belt body, at least two teeth projecting from the belt body, the belt comprising a pitch length measured between the at least two teeth on the belt, one of the at least two teeth having a tooth tip and a profile comprising a first radius and a second radius and a third radius disposed between a first linear segment and a second linear segment, the sprocket having a groove for receiving one of the at least two teeth, the groove profile comprising a first radius and a second radius and the third radius and a fourth radius, each of which is connected in series to the others and each of which is unequal in length to the other radii, the tooth having a width that is approximately 35% of a pitch length at 90% of a tooth height so as to result in an interference fit between the one of at least two teeth and groove at 90% of the tooth height; and a volume between the tooth tip and the groove.