Braze Gap Fixture With Lever Arms for Thermal Joint Contact
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Solution Overview
Problem
During thermal processing, such as brazing, components experience relative movements due to thermal expansion and contraction, leading to undesirable gaps and challenges in achieving consistent, high-quality joints, particularly in complex assemblies like automotive condensers.
Innovation Solution
A tool system employing lever arms with cam surfaces and weight arms that pivot to apply a continuous, tunable force to maintain contact between components, allowing for thermal expansion while preventing gap formation, using a fixture that supports the assembly and transports it through a furnace.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If components are rigidly fixed to prevent movement during thermal processing, then gap formation is prevented, but thermal expansion is restricted causing stress and potential deformation
Solution Approach 1:
The fixture uses lever arms with cam surfaces that allow dynamic adjustment of component positioning during thermal processing. The cam surfaces enable the components to move freely during thermal expansion while the lever arms automatically apply corrective forces to maintain proper spacing, resolving the contradiction between preventing gap formation and allowing thermal expansion.
Solution Approach 2:
The system changes the physical state of the constraint mechanism by using temperature-responsive materials or mechanisms that adjust their stiffness or geometry in response to temperature changes. This allows the fixture to be rigid when needed for gap control and compliant when thermal expansion occurs, preventing both gap formation and thermal stress.
2Manufacturing precision
If heavy clamps are used to maintain component contact, then gap formation is prevented, but component deformation and heat extraction occur
Solution Approach 1:
The lever arms with cam surfaces act as intermediary mechanisms between the fixture and components. Instead of directly clamping the components with heavy forces, the cam surfaces provide a mechanical advantage that applies gentle, distributed pressure to maintain contact while preventing direct stress concentration on the components, thus avoiding deformation.
Solution Approach 2:
The system replaces traditional heavy mechanical clamps with a lever arm and cam surface mechanism that uses mechanical advantage to achieve the same gap control function with minimal force. This substitution eliminates the need for heavy clamps that would deform components or extract excessive heat.
3Stability of the object's composition
If components are allowed to move freely during thermal expansion, then thermal stress is reduced, but gap formation at joints occurs
Solution Approach 1:
The fixture allows components to move dynamically during thermal expansion by providing sliding surfaces or adjustable lever arms that track the thermal growth of components. The cam surfaces automatically adjust the positioning to maintain proper spacing, ensuring both thermal stress management and joint alignment are achieved simultaneously.
Solution Approach 2:
The lever arm mechanism provides continuous feedback on component position during thermal processing. As components expand or contract, the lever arms detect the movement and automatically adjust the positioning through the cam surfaces, maintaining proper joint alignment without restricting thermal expansion. This closed-loop mechanical feedback ensures both thermal stress management and manufacturing precision.
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 tool system effectively maintains contact between components during temperature changes, ensuring consistent joint formation and improved product quality by allowing thermal expansion without restriction, while the tailored force prevents gap formation and enhances braze-ability.
Implementation Method 1
a lever arm having a body, a connection configured to allow the body to pivot, and a weight arm extending from the body
Implementation Method 2
a weight arm extending from the body and over one of the components. In response to movement of the components, the lever arm is configured to pivot at the connection, while the weight arm is configured to generate a force transferred through the body
Implementation Method 3
a cam surface defined by the body and configured to engage the second component
Implementation Method 4
The fixture transports the assembly through a furnace within which temperatures are at a level sufficient to effect brazing
Implementation Method 5
The braze temperature state effects flow of the brazing material
Implementation Method 6
A brazing oven/furnace may include multiple zones such as for preheating and drying and for subjecting the component assembly to various controlled environmental conditions to control the quality of metal melting and joining
Data Source
AI summary
A tool system controls and prevents gaps during processing of assemblies at elevated temperature. Gaps are prevented from arising at joints between components during temperature changes. The tool system includes a lever arm having a body, a connection configured to allow the body to pivot, a cam surface defined by the body and configured to engage the second component, and a weight arm extending from the body and over the second component. In response to movement of the second component, the lever arm is configured to pivot at the connection while the weight arm is configured to generate a force transferred through the body to the second component to maintain contact at the joint between the first component and the second component. A rod may be connected with the lever arm for added weight.