Vacuum Pump Stator Heating with Axial Seal and Gap Control
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Solution Overview
Problem
Conventional vacuum pumps face issues with reaction product adhesion due to temperature differences between the rotor and stator, leading to premature wear and contact between components, as the heating method in existing technologies restricts thermal expansion and causes unnatural stress.
Innovation Solution
A vacuum pump design featuring a stator heating member with a gap to the base, allowing for concentric fixation and axial sealing, which enables thermal expansion without reducing the gap between the rotor and stator, using positioning pins and a restriction member to prevent movement towards the atmosphere, and employing a heat insulation member to manage heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the heating target member is directly heated to increase the temperature inside the pump, then the adhesion of reaction products is suppressed, but the heating target member expands thermally causing unnatural stress and reducing the gap between rotor and heating target member
Solution Approach 1:
The patent introduces a heating member as an intermediary component that indirectly heats the heating target member through thermal conduction. The heating member is positioned in the through-hole of the base and transfers heat to the heating target member, allowing temperature increase while maintaining the gap between the rotor and heating target member, thus preventing direct contact and improving reliability
Solution Approach 2:
The heating system is segmented into separate components: the heating member (heater) and the heating target member (stator or exhaust pipe). This segmentation allows independent thermal management, where the heating member can be heated to high temperatures without directly causing thermal expansion of the heating target member that would reduce the rotor gap
2Stability of the object's composition
If the heating target member is fixed to the base to stabilize its position, then the structural stability is improved, but the thermal expansion is restricted generating unnatural stress
Solution Approach 1:
The heating target member is designed with dynamic positioning capability. It is not rigidly fixed to the base but can move axially within the through-hole to accommodate thermal expansion. The heating member is fixed to the base while the heating target member remains movable, allowing it to expand freely in the radial direction without generating unnatural stress
3Manufacturing precision
If the heating member is fixed to the stator to maintain concentric alignment, then the positioning accuracy is improved, but the thermal expansion of the stator is disturbed causing gap reduction
Solution Approach 1:
Positioning pins act as intermediary elements that establish concentric alignment between the heating member and the through-hole without creating rigid constraints. The positioning pins fit into corresponding holes in the base and heating member, providing precise radial positioning while allowing axial movement, thus maintaining the gap between rotor and stator during thermal expansion
4Difficulty of detecting and measuring
If the through-hole in the base is made larger to accommodate heating member movement, then the thermal expansion freedom is improved, but the vacuum sealing becomes difficult
Solution Approach 1:
An axial seal member (flexible sealing element) is installed in the through-hole of the base to maintain vacuum sealing while accommodating the heating member's movement. The seal member can deform elastically to allow axial displacement of the heating member during thermal expansion, thus maintaining both vacuum sealing and thermal expansion freedom
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 the reliability of the vacuum pump by preventing unnatural stress and maintaining a consistent gap between the rotor and stator, thereby reducing the risk of contact and extending the operational lifespan.
Implementation Method 1
a heating member passing through the through hole from an atmosphere side to a vacuum side to have thermal contact with an outer peripheral surface of the stator to heat the stator
Implementation Method 2
an axial seal member which vacuum-seals a gap between the through hole and the heating member
Implementation Method 3
Pin holes are formed on the heating member and the base, and positioning pins for achieving the concentric state are inserted into the pin holes
Implementation Method 4
The vacuum pump further comprises a restriction member restricting movement of the heating member toward the atmospheric side when the fixing is released
Data Source
AI summary
A vacuum pump comprises a cylindrical rotor; a cylindrical stator which discharges gas in cooperation with the rotor; a base housing at least a part of the stator and having a through hole formed at a position facing an outer periphery of the stator; a heating member passing through the through hole from an atmosphere side to a vacuum side to have thermal contact with an outer peripheral surface of the stator to heat the stator; and an axial seal member which vacuum-seals a gap between the through hole and the heating member.