Asymmetric Cutout Pin for Precise Play-Free Assembly
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Solution Overview
Problem
Existing pins used for joining parts suffer from friction-induced deformation, leading to inaccurate and non-repeatable relative positioning, potential damage, and difficulty in assembly and disassembly.
Innovation Solution
A pin design with a cutout separating a fixed and flexible part, featuring an asymmetrical projection, facilitates insertion and ensures precise, repeatable positioning by distributing stress and generating elastic restoring forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pin is made with tight adjustments between pin and parts to limit mechanical play, then positioning precision is improved, but friction increases making assembly and disassembly difficult
Solution Approach 1:
The pin is segmented into a fixed part and a flexible part through a transverse cutout. The fixed part maintains positioning precision while the flexible part provides elastic deformation capability to reduce friction during assembly and disassembly operations.
Solution Approach 2:
The pin structure changes from completely rigid to having a flexible portion that can elastically deform. This parameter change allows the pin to adapt during assembly, reducing friction while maintaining positioning accuracy through the fixed part.
2Ease of operation
If the pin is split axially to present radial elasticity for easier engagement, then assembly ease is improved, but positioning accuracy deteriorates due to undetermined deformation
Solution Approach 1:
Different parts of the pin have different properties: the fixed part maintains rigidity for positioning accuracy while the flexible part provides elasticity for easy engagement. The asymmetric cutout configuration ensures controlled deformation behavior.
Solution Approach 2:
The cutout has an asymmetric projection shape that controls the direction and manner of flexible part deformation. This asymmetry ensures that clearances are taken up in a determined direction, preventing undetermined deformation that would compromise positioning accuracy.
3Measurement precision
If tight clearances are used between pin and housing, then positioning precision is improved, but damage risk increases due to friction during assembly
Solution Approach 1:
The flexible part of the pin undergoes preliminary elastic deformation during assembly to take up clearances before the fixed part engages with the housing. This preliminary action reduces friction and prevents damage while maintaining tight clearances for positioning precision.
Solution Approach 2:
The potential harmful effect of friction in tight clearances is converted into a beneficial elastic deformation of the flexible part. This deformation allows the pin to navigate tight tolerances without damage, while the fixed part ensures positioning precision is maintained.
4Measurement precision
If the pin is made rigid to prevent deformation, then positioning accuracy is improved, but assembly difficulty increases due to high friction
Solution Approach 1:
The pin is divided into fixed and flexible segments. The fixed part ensures positioning accuracy by preventing deformation, while the flexible part eases assembly by elastically deforming to reduce friction during engagement.
Solution Approach 2:
The pin has localized flexibility in the flexible part while maintaining overall rigidity in the fixed part. This local quality differentiation allows the pin to be both easy to assemble and accurate in positioning, resolving the contradiction between rigidity and flexibility.
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
Ensures precise and repeatable relative positioning of parts, reducing damage and simplifying assembly/disassembly while maintaining accuracy over time.
Implementation Method 1
the flexible part is forced to deform so as to generate an elastic restoring force at the origin of clamping forces of the second end on the second part
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a pin (10) extending along a longitudinal axis between a first end (100) intended to be secured to a first part (30) and a second end (200) intended to be engaged in a housing (21) of a second part (20) according to an adjustment without mechanical play, the second end (200) having a cutout (210) delimiting a fixed part (220) and a flexible part (230) and passing right through the second end (200) transversely to the longitudinal axis, the cutout (210) being configured so as to have, in a plane P containing the longitudinal axis, a projection whose general shape is asymmetrical.