Pulley Bearing Shield Structure for Sleeve Retention and Pollution Protection
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Solution Overview
Problem
Existing pulley devices face issues with mechanical contact and pollution ingress, leading to reduced lifespan and performance due to manufacturing tolerance requirements and susceptibility to environmental pollutants.
Innovation Solution
A pulley device design featuring a freely mounted sleeve within the inner ring bore with an annular protection shield providing axial retention and reduced axial and radial spatial requirements, enhancing concentricity and pollution protection while simplifying manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a sleeve is rigidly connected to the inner ring bore to prevent relative movement, then the mechanical connection stability is improved, but the manufacturing precision requirements increase due to tolerance accumulation
Solution Approach 1:
The device is divided into functionally independent segments: the sleeve is separated from the inner ring bore, allowing each component to be manufactured independently within standard tolerances. The sleeve is freely mounted in the bore without requiring precise fit, eliminating the need for extremely tight tolerance coordination between these two parts.
Solution Approach 2:
The protection shield acts as an intermediary element that provides the necessary mechanical constraint and positioning. Instead of relying on a precise rigid connection between the sleeve and bore, the shield mediates the relationship, allowing the sleeve to be freely mounted while still preventing harmful relative movements through the shield's structural support.
2Object-affected harmful factors
If sealing means are added to protect against pollution, then the protection against environmental pollutants is improved, but the device complexity increases
Solution Approach 1:
The protection shield serves multiple functions simultaneously: it provides mechanical support and positioning for the freely mounted sleeve, prevents pollution ingress to the bearing chamber, and eliminates the need for separate sealing means. By merging these functions into a single structural element, the device achieves effective pollution protection without increasing complexity.
Solution Approach 2:
The protection shield is designed as a multi-functional component that combines structural support, positioning, and pollution protection functions. This universal element replaces what would otherwise require multiple separate components (sleeve connection mechanism, seals, and protective shields), thereby reducing overall device complexity while maintaining comprehensive protection.
3Ease of manufacture
If the sleeve is freely mounted in the bore, then the manufacturing tolerances are relaxed, but the axial spacing and concentricity control become more challenging
Solution Approach 1:
The protection shield acts as an intermediary that establishes and maintains proper axial spacing and concentricity. The shield's structure provides reference surfaces and mechanical constraints that guide the freely mounted sleeve into the correct position, ensuring proper alignment and spacing without requiring precise manufacturing tolerances on the sleeve-bore interface.
Solution Approach 2:
The protection shield is installed first to establish the correct axial positioning and concentricity reference. This preliminary action creates a stable framework that subsequently guides the sleeve installation, ensuring proper alignment is achieved through the shield's pre-positioned structural features rather than relying on precise sleeve-bore fit.
Data Source
AI summary
A pulley device for a transmission element having a pulley, a bearing, and at least one sleeve mounted freely in the bore of the inner ring of the bearing. The pulley device includes at least one annular protection shield, the shield retained axially in a first element from the pulley and coming into immediate proximity with the other element, the other element having at least one shoulder projecting radially ensuring that it is axially retained with the shield.