C-Shaped Pulley Structure for Belt Wear and Axial Stability
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Solution Overview
Problem
Existing pulley devices for tensioning idlers or runner rollers suffer from early belt wear and radial deformation under heavy loads, as they lack sufficient rigidity and effective belt support.
Innovation Solution
A pulley device with a rotatable outer ring and fixed inner ring, featuring C-shaped pulley parts with material deformations on the radial lateral surfaces, which act as axial stops to prevent axial movement and ensure efficient belt support, even under heavy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pulley is tightened to the outer ring of bearing, then the pulley can be securely mounted, but the pulley can slightly axially move during service use and may be deformed radially inwards by bending under the action of the belt
Solution Approach 1:
The patent applies preliminary action by pre-forming material deformations (crimps) on the outer ring surface before the pulley is assembled. These crimps create protrusions that act as axial stops, preventing axial movement of the pulley during service. The material deformations are created in advance during manufacturing, so when the pulley is mounted, these pre-formed features immediately provide axial positioning and prevent the instability issue described in the contradiction.
Solution Approach 2:
The patent applies local quality by creating localized material deformations at specific positions on the outer ring rather than changing the entire structure. The crimps are formed at discrete locations around the circumference, creating localized protrusions that provide axial stopping function. This localized approach maintains the overall structural integrity while providing the necessary axial positioning stability without affecting the global rigidity of the bearing assembly.
2Ease of manufacture
If the pulley is made with overlapping male and female parts, then the pulley can be assembled, but an annular recess is formed on the outer portion which causes early wear of the belt
Solution Approach 1:
The patent applies the taking out principle by removing the problematic annular recess feature from the pulley design. Instead of having overlapping male and female parts that create a recess, the invention uses a solid pulley structure where the belt contacts only the outer cylindrical surface. The harmful recess is completely eliminated from the design, allowing the belt to run smoothly without entering any recesses that would cause premature wear.
Solution Approach 2:
The patent applies inversion by reversing the traditional overlapping parts approach. Rather than using male and female overlapping sections to form the pulley, the invention uses a solid, continuous structure where the belt contacts the outer surface. This inverted approach eliminates the recess formation issue while maintaining assembly capability through alternative mounting methods using the material deformations on the bearing.
3Object-affected harmful factors
If a damping ring is housed within a C-shaped pulley, then vibrations from the belt can be damped and radial inward deformation can be limited, but the pulley can still be deformed under heavy loads
Solution Approach 1:
The patent applies merging by combining the bearing and pulley into a more integrated structure. The material deformations are formed directly on the outer ring of the bearing, creating a unified assembly where the bearing and pulley work together as a single structural unit. This merged design provides both vibration damping through the material deformations and enhanced load resistance, as the bearing itself becomes part of the load-bearing structure rather than being a separate component.
Solution Approach 2:
The patent applies composite materials by using different material properties in different parts of the assembly. The bearing outer ring is made of a material that can be deformed to create crimps, while maintaining sufficient strength to resist heavy loads. The pulley is made of a material suitable for belt contact and load bearing. This composite approach allows the material deformations to provide vibration damping while the overall composite structure resists heavy loads effectively.
Data Source
AI summary
A pulley device provides a pulley and a bearing. The pulley has at least one C-shaped pulley part having an inner portion mounted on the bearing, an outer portion having an outer cylindrical surface dedicated to interact with a belt or a chain, and an intermediate portion extending substantially radially between axial ends of inner and outer portions on one axial side of pulley device. The outer cylindrical surface of outer ring is provided with at least one material deformation forming an axial stop for the pulley.