Idler Pulley with Bulging Profile for Belt Deviation Control
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Solution Overview
Problem
In belt driving apparatuses for transfer robots, the deviation of an endless toothed belt due to inaccuracies in pulley axis alignment and belt variations leads to unstable operation and potential breakage, especially when increasing movement distance or speed.
Innovation Solution
The apparatus includes a driving pulley and first driven pulley with teeth on their outer surfaces, an endless toothed belt with inclined teeth, and idler pulleys with a bulging contact surface to maintain belt tension and alignment, featuring an angle adjustment mechanism and auto tension mechanism to prevent deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the length of the output belt is increased to increase the movement distance of the hand, then the movement distance is improved, but the amount of displacement of the output belt in the width direction increases, which increases the possibility of belt deviation and contact with collar portions
Solution Approach 1:
The idler pulley is designed with non-uniform diameter along the width direction of the belt contact surface, with a center portion having a greater diameter than end portions. This local variation in geometry creates a positioning effect that prevents belt deviation in the width direction while allowing the belt to run stably over long distances.
2Productivity
If the travel speed of the belt is increased to enhance productivity, then the transfer speed is improved, but the amount of displacement of the output belt in the width direction increases, which increases the possibility of belt deviation and contact with collar portions
Solution Approach 1:
The idler pulley's non-uniform diameter profile (center portion greater than end portions) creates a mechanical constraint that counteracts the increased lateral displacement forces generated at higher travel speeds, maintaining belt stability even during high-speed operation.
3Productivity
If toothed pulleys and timing belt are used to increase transfer speed, then the transfer speed is improved, but slipping prevention requires precise parallel alignment of pulley rotation axes, which is difficult to achieve due to manufacturing and mounting errors
Solution Approach 1:
The idler pulley acts as an intermediary element between the driving and driven pulleys. Its non-uniform diameter profile compensates for misalignment in the pulley axes by mechanically guiding the belt back to the correct position, thereby preventing slipping even when precise parallel alignment cannot be achieved.
4Adaptability or versatility
If the output belt runs with deviation due to pulley axis errors and belt variations, then the system operates with manufacturing tolerances, but the edge of the output belt contacts the collar portion causing unstable operation and potential breakage
Solution Approach 1:
The idler pulley's varying diameter along the belt width creates a self-correcting mechanism that accommodates belt variations and axis misalignment tolerances while preventing the belt edge from contacting the collar portion, thereby maintaining stable operation despite manufacturing imperfections.
Data Source
AI summary
A belt driving apparatus includes a driving pulley, a driven pulley and an endless toothed belt. Each of the driving pulley and the driven pulley includes an outer circumference surface provided with a plurality of teeth. The toothed belt, wound around the driving pulley and the first driven pulley, includes an inner surface provided with a plurality of teeth arranged to mesh with the teeth of the driving pulley and the first driven pulley. The belt driving apparatus also includes an idler pulley having a belt contact surface coming into contact with the outer surface of the toothed belt. As viewed along the width direction of the belt contact surface, the idler pulley includes a center portion and two end portions sandwiching the center portion. The center portion of the idler pulley is greater in diameter than each of the two end portions.