V-Belt Pulley Groove Angles for Durability Across Speed Layouts
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Solution Overview
Problem
Existing belt-type transmissions face challenges in achieving optimal durability and efficiency across varying speed layouts due to limitations in pulley-groove V angle configurations, which affect the wrapping diameter and contact pressure distribution of the V-belt, leading to issues like buckling and cord separation.
Innovation Solution
The belt-type transmission employs a double cogged V-belt system with adjustable pulley-groove V angles on both the drive and driven pulleys, where the pulley-groove V angles are optimized to be larger than the average belt V angle in low-speed layouts for increased durability and smaller than the average belt V angle in high-speed layouts to manage contact pressure and torque effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pulley-groove V angle is made smaller than the belt V angle, then the wrapping diameter can be reduced for compact design, but the contact pressure distribution becomes uneven causing buckling and reduced durability
Solution Approach 1:
The patent applies local quality by making the pulley-groove V angle vary across different radial positions of the pulley. Specifically, the pulley-groove V angle is made smaller than the belt V angle in certain regions (such as the inner peripheral portion) and equal to or larger than the belt V angle in other regions (such as the outer peripheral portion), creating a non-uniform angular configuration that optimizes both compactness and durability locally across the pulley surface.
Solution Approach 2:
The patent changes the geometric parameter of the pulley-groove V angle to resolve the contradiction. By adjusting the pulley-groove V angle to be different from the belt V angle in specific regions, the patent achieves better contact pressure distribution and prevents buckling while maintaining reduced wrapping diameters for compact design.
2Reliability
If the pulley-groove V angle is made equal to the belt V angle, then the contact pressure is evenly distributed, but the wrapping diameter increases reducing compactness
Solution Approach 1:
Rather than uniformly setting the pulley-groove V angle equal to the belt V angle across the entire pulley, the patent applies local quality by making the pulley-groove V angle equal to or slightly larger than the belt V angle only in specific regions (such as outer peripheral portions), while making it smaller in other regions (such as inner peripheral portions). This localized approach maintains adequate contact pressure distribution while reducing the overall wrapping diameter.
3Reliability
If the pulley-groove V angle varies across the pulley radius, then both compactness and durability are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements local quality through a graded variation of the pulley-groove V angle across the radial direction. This gradual change from smaller angles at inner periphery to equal or larger angles at outer periphery provides a practical compromise that improves durability and compactness while remaining manufacturable through conventional machining processes, avoiding overly complex non-uniform geometries.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the durability of the V-belt by maintaining high contact pressure on the inner periphery in low-speed layouts and reducing shearing forces, while in high-speed layouts, it prevents oscillation of the compression rubber layer, resulting in extended belt traveling life and improved performance across the entire speed range.
Implementation Method 1
A V-belt 13 is extended between and wrapped around a drive pulley 11 and a driven pulley 12
Data Source
AI summary
A belt-type transmission includes a drive pulley, a driven pulley, and a V-belt. In at least a certain range of a low-speed layout, a pulley-groove V angle of a portion of a drive pulley where the V-belt is wrapped is larger than an average belt V angle when the V-belt is bent at a curvature corresponding to a wrapping diameter of the V-belt with respect to the drive pulley, and a pulley-groove V angle of a portion of a driven pulley where the V-belt is wrapped is larger than an average belt V angle when the V-belt is bent at a curvature corresponding to the wrapping diameter of the V-belt with respect to the driven pulley.