Linear Motor Actuator Cooling Stack With Resilient Coil Preload
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Solution Overview
Problem
The existing actuators in lithographic apparatuses face challenges with thermal management due to tolerances in the distance between the coil and cooling plates, leading to inconsistent heat transfer and potential overheating, which can result in failure.
Innovation Solution
The actuator design includes a stacked structure with a coil split into two parts, each facing a cooling plate, and a filling element, such as a resilient foam or coil spring, to maintain a consistent distance and improve thermal contact, thereby reducing thermal resistance and accommodating dimensional tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the coil and cooling plate is set with standard tolerances, then the manufacturing cost is reduced, but the thermal resistance becomes inconsistent leading to overheating risks
Solution Approach 1:
The patent changes the physical state of the filling element from rigid to resilient/compressible, allowing it to deform and accommodate dimensional variations. This parameter change in material properties enables the system to maintain consistent thermal contact pressure despite variations in component dimensions, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The resilient filling element acts as a pre-compression mechanism that compensates for dimensional tolerances before the coil operates. By compressing the resilient material during assembly, the patent creates a buffer that maintains consistent thermal contact despite variations in coil or cooling plate dimensions, preventing overheating without requiring high manufacturing precision.
2Force
If high electrical current is applied to generate high magnetic field, then the actuator force increases, but the electrical dissipation and heat generation increase causing potential failure
Solution Approach 1:
The resilient filling element serves as a thermal intermediary between the coil and cooling plate. It maintains optimal thermal contact pressure, ensuring efficient heat transfer from the coil to the cooling plate when high currents are applied. This mediator prevents temperature buildup that would otherwise lead to failure during high-force operation.
Solution Approach 2:
The patent replaces rigid mechanical contact with a resilient contact system. Instead of relying on precise mechanical positioning and rigid contact surfaces, the resilient filling element provides adaptive thermal contact that maintains consistent heat transfer efficiency regardless of dimensional variations, enabling reliable high-current operation.
3Ease of manufacture
If the coil dimension tolerance is larger than the actuator total dimension tolerance, then the manufacturing complexity is reduced, but the distance to cooling plate varies causing inconsistent heat transfer
Solution Approach 1:
The patent changes the filling material from rigid to resilient, allowing it to accommodate the larger coil dimension tolerances. This parameter change enables the system to maintain consistent thermal contact pressure despite variations in coil dimensions, resolving the contradiction between ease of manufacture and heat transfer consistency.
Solution Approach 2:
The patent uses a composite structure combining the coil, resilient filling element, and cooling plate. The resilient material acts as a compliant interface that bridges the dimensional tolerance gap between the coil and cooling plate, ensuring consistent thermal contact without requiring high manufacturing precision for either component.
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 design enhances thermal behavior by ensuring consistent heat transfer and reducing the risk of overheating, allowing for reliable operation at high currents with minimized safety margins.
Implementation Method 1
the resilient element being compressed in a direction perpendicular to planes of the cooling plates
Implementation Method 2
The cooling plates may conduct heat away from the coil, thereby lowering a temperature of the coil
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An actuator comprises a coil, a first cooling plate and a second cooling plate. The cooling plates are configured to cool the coil. The first and second cooling plates are arranged at opposite sides of the coil to be in thermal contact with the coil. The coil comprises a first coil part and a second coil part, the first coil part facing the first cooling plate and the second coil part facing the second cooling plate, the first and second coil parts being separated by a spacing there between. The first cooling plate, the first coil part, the spacing, the second coil part and the second cooling plate form a stacked structure whereby the coil parts are arranged between the cooling plates and the spacing is arranged between the coil parts. The actuator further comprises a filling element arranged in the spacing. The filling element to push the first coil part towards the first cooling plate and to push the second coil part towards the second cooling plate.