Reduced Backlash Joint Thermal Modification
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Solution Overview
Problem
Existing mechanical joints and chains used in applications like surgical robotics experience backlash due to fitting issues, leading to imprecise movements and increased complexity and cost in precision machining to address these problems.
Innovation Solution
A method of creating precision fits between mechanical components by thermally modifying a lower melting point component in an interference relation with a higher melting point component, allowing material flow to relieve interference stresses and achieve a precise fit without the need for expensive precision machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precision machining is used to improve joint fit, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the physical state of the polymer material by heating it above its glass transition temperature, transforming it from a rigid state to a compliant state. This allows the polymer to deform and conform to the mating surface, achieving precision fit through thermal parameter change rather than complex machining operations
Solution Approach 2:
The patent replaces mechanical precision machining with a thermal-field-based approach. Instead of using complex mechanical tools to machine surfaces to high precision, the invention uses thermal energy to soften the polymer and allow it to self-conform, substituting a mechanical precision system with a thermal-forming system
2Manufacturing precision
If interference fit is used to reduce backlash, then joint precision is improved, but interference stresses cause material deformation and fit issues
Solution Approach 1:
The patent applies thermal energy to change the physical state of the polymer, raising its temperature above the glass transition temperature. This parameter change transforms the polymer from a brittle, stress-sensitive state to a compliant, deformable state, allowing it to accommodate interference fit stresses without permanent deformation
Solution Approach 2:
The patent utilizes the glass transition phase transition of the polymer material. By heating the polymer above its glass transition temperature, the material transitions from a glassy, rigid state to a rubbery, compliant state, enabling it to flow and conform under interference fit conditions without suffering from stress-induced deformation issues
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
This approach reduces backlash and enhances the precision and robustness of mechanical joints and chains, improving their performance and reducing manufacturing costs.
Implementation Method 1
heating the mating surface above a glass transition temperature or melting temperature of the mating surface
Implementation Method 2
heating the mating surface above a glass transition temperature or melting temperature of the mating surface
Implementation Method 3
heating the mating surface above a glass transition temperature or melting temperature of the mating surface
Implementation Method 4
induce flow of material to an area between the first joint component and the second joint component
Data Source
Figure 1(a)~1(c)
Figure 1B
Figure 2A~2B
AI summary
A joint and a corresponding method of creating a precision-fit joint, including creating a mating surface on a first joint component so that the mating surface includes one or more interfering features, connecting a second joint component with the mating surface such that the interfering feature is compressed, and heating the mating surface above a glass transition temperature or melting temperature of the mating surface, or otherwise treating the surface, so as to induce flow of material from the interfering feature to a area of relatively low pressure between the first joint component and the second joint component.