Vacuum Pump Stator Binding for Thermal Gap Control
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Solution Overview
Problem
The performance of thread groove pumps is reduced due to increased gap amounts between the rotating body and stator caused by thermal expansion, which is exacerbated by changes in internal temperature settings during semiconductor manufacturing processes.
Innovation Solution
A vacuum pump design that includes a binding means made of a material with a lower linear expansion coefficient than the stator, disposed on the outer periphery of the thread groove stator to reduce radial deformation during thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the temperature of the stator is increased to prevent reaction product deposition, then the stator temperature is maintained above sublimation temperature, but the gap amount between the rotating body and stator increases due to thermal expansion, reducing pump performance
Solution Approach 1:
The invention utilizes differential thermal expansion by selecting a binding means material with a lower linear expansion coefficient than the stator material. When the stator temperature increases to prevent reaction product deposition, the stator expands more than the binding means, allowing the binding means to maintain a tighter fit and suppress radial deformation, thereby minimizing gap increase and preserving exhaust performance
Solution Approach 2:
The invention changes the material parameter (linear expansion coefficient) of the binding means to be lower than that of the stator. This parameter difference enables the binding means to effectively constrain the stator's radial expansion when temperature increases, preventing excessive gap formation while allowing the stator to reach temperatures above the sublimation point of reaction products
2Adaptability or versatility
If the internal temperature setting is changed to reduce inventory, then the pump can accommodate various manufacturing processes, but the gap amount between the rotating body and stator changes due to thermal expansion, reducing exhaust performance
Solution Approach 1:
The binding means with lower linear expansion coefficient compensates for the stator's thermal expansion across different temperature settings. Whether the stator is at a lower temperature for inventory reduction or higher temperature for process versatility, the binding means maintains appropriate constraint, ensuring the gap amount remains within acceptable ranges and exhaust performance is preserved across all operating conditions
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 design effectively suppresses the increase in gap amount between the rotating body and stator, maintaining pump performance across varying internal temperatures and preventing stator damage.
Implementation Method 1
a binding means, which is formed of a material having a linear expansion coefficient lower than a linear expansion coefficient of a material of the stator and reduces radial deformation at a time of thermal expansion of the stator
Data Source
AI summary
A vacuum pump includes a casing having an inlet port, and enclosing a rotating body, a thread groove stator which is substantially cylindrical and is disposed on an outer periphery of the rotating body, and a thread groove which is formed in at least one of an outer peripheral surface of the rotating body and an inner peripheral surface of the thread groove stator, the vacuum pump exhausting gas sacked from a side of the inlet port to outside of the casing by rotating the rotating body, wherein a binding means, which is formed of a material having a linear expansion coefficient lower than a linear expansion coefficient of a material of the thread groove stator and reduces radial deformation at a time of thermal expansion of the thread groove stator, is disposed on an outer periphery of the thread groove stator.