Bar Pin Bushing Precompression for Heavy Truck Suspension Loads
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Solution Overview
Problem
Existing bar pin bushing assemblies for vehicular systems, such as suspensions and axle systems, are not robust enough to handle high radial and axial loads and high articulation angles encountered in heavy truck applications, leading to inadequate stress distribution and load-carrying capacity.
Innovation Solution
A bar pin bushing assembly with a compressible rubber section of uniform thickness, surrounded by a plurality of outer metal shell segments that are mold-bonded and radially compressed upon insertion, providing precompression and increased hoop strength, along with axial voids to facilitate uniform stress distribution and higher load-carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If snap ring connections are used to assemble the bushing components, then the assembly is easier to manufacture, but the radial and axial load-carrying capacity is insufficient for heavy truck applications
Solution Approach 1:
The rubber bushing is pre-compressed during the molding process itself, before assembly into the final application. The molding tooling applies radial compression to the rubber while it cures, creating a pre-compressed state that eliminates the need for separate compression springs or snap rings to maintain the compressed state during service.
Solution Approach 2:
The invention uses a composite structure combining metal end caps with rubber bushing material. The metal end caps provide structural strength for high load applications, while the rubber provides compliance and stress distribution. This composite construction enables the bushing to withstand heavy radial and axial loads in truck applications.
2Adaptability or versatility
If the rubber section has non-uniform thickness, then the bushing can accommodate articulation movements, but the stress distribution becomes uneven leading to reduced fatigue life
Solution Approach 1:
The rubber bushing features a uniform thickness in the radial direction, creating even stress distribution across the rubber cross-section. This uniform geometry is achieved through controlled molding processes that maintain consistent rubber thickness, preventing stress concentration points that would reduce fatigue life during articulation movements.
3Device complexity
If the rubber bushing is not pre-compressed, then the assembly process is simpler, but the bushing cannot withstand high radial and axial loads in heavy truck applications
Solution Approach 1:
The rubber bushing is pre-compressed during the molding process itself, before assembly into the final application. The molding tooling applies radial compression to the rubber while it cures, creating a pre-compressed state that eliminates the need for separate compression springs or snap rings to maintain the compressed state during service.
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
The solution enhances bushing fatigue and increases radial and axial load-carrying capacity, allowing for high articulation angles while maintaining robustness and durability in heavy truck applications.
Implementation Method 1
the plurality of outer metal shells are moved radially inwardly to compress the compressible rubber section to provide for a significantly precompressed rubber bushing assembly
Implementation Method 2
a plurality of outer metal shell segments that are mold bonded to the compressible rubber section
Data Source
AI summary
A bar pin bushing assembly for connecting components including a bar pin having at least one end with at least one bore to receive a fastener, the bar pin having a central portion having a diameter that is greater than a width or diameter of the at least one end of the bar pin, a compressible rubber section having a uniform thickness positioned around the central portion of the bar pin, the compressible rubber section further extending around downwardly tapering surfaces adjacent the central portion of the bar pin, a plurality of outer metal shells mold bonded to the compressible rubber section, wherein when the bushing assembly is inserted into a hub, the plurality of outer metal shells are configured to radially compress the compressible rubber section to provide a precompressed bushing assembly. A method of assembling the bar pin bushing assembly is also disclosed.