Vacuum Pump Stator Surface Roughness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional vacuum pumps face challenges in preventing the backflow of particles from the vacuum pump towards the vacuum chamber, particularly due to irregular reflection of small particles on the surface roughness of the stator component, which limits the effectiveness of existing bounce direction control methods.
Innovation Solution
The vacuum pump incorporates a stator component with an inclined and smooth upper surface and a recess portion connected to a particle trapping space, positioned near the gap of the rotor blade, to prevent particles from bouncing back towards the turbomolecular pump portion, thereby reducing backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the upper surface of the stator component is tilted to control particle bouncing direction, then the particle reflection direction is improved, but small particles (size 10^-3 times the surface roughness height difference) are irregularly reflected due to surface roughness, reducing the effectiveness of bounce direction control
Solution Approach 1:
The patent changes the surface roughness parameter of the stator component upper surface to be sufficiently smooth (Ra ≤ 0.8 μm, preferably Ra ≤ 0.4 μm). This parameter change ensures that small particles are reflected regularly according to the tilt angle rather than being irregularly scattered, thereby resolving the contradiction between controlling bounce direction and achieving precise particle reflection direction.
2Object-affected harmful factors
If a bounce back prevention means is added downstream of the turbomolecular pump portion, then particle backflow prevention is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by modifying only the upper surface of the stator component with specific smoothness (Ra ≤ 0.8 μm) and tilt angle (10° to 45°), rather than redesigning the entire vacuum pump system. This localized modification effectively prevents particle backflow while minimizing the increase in device complexity.
3Manufacturing precision
If the upper surface of the stator component is made smooth (Ra ≤ 0.8 μm), then regular reflection of small particles is improved, but the manufacturing difficulty increases
Solution Approach 1:
The patent specifies a quantitative parameter range for surface roughness (Ra ≤ 0.8 μm, preferably Ra ≤ 0.4 μm) that balances manufacturing feasibility with particle reflection performance. This parameter specification enables manufacturers to achieve the required smoothness using conventional polishing techniques while ensuring effective particle control.
Solution Approach 2:
The patent combines surface smoothness control with asymmetric tilting (10° to 45°) to create a unified surface design that achieves both manufacturability and particle reflection effectiveness. The asymmetric tilt provides directional control while the smoothness ensures regular reflection, together resolving the manufacturing precision versus ease of manufacture contradiction.
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 configuration effectively reduces the percentage of particles flowing back towards the vacuum chamber by controlling the bouncing direction and capturing particles, enhancing the prevention of contamination within the vacuum chamber.
Implementation Method 1
the particle that collides with the upper surface 9A of the thread groove pump portion stator (stator component) is irregularly reflected
Implementation Method 2
an upper surface of the stator component that faces the turbomolecular pump portion is inclined and smooth
Data Source
AI summary
Provided is a vacuum pump suitable for preventing the backflow of a particle from the vacuum pump toward a vacuum chamber. The vacuum pump includes a turbomolecular pump portion exhausting gas molecules by a rotor blade and a stator blade, and a thread groove pump portion provided downstream of the turbomolecular pump portion and exhausting the gas molecules by a thread groove flow path formed by a cylindrical rotary component (cylindrical portion) and a cylindrical stator component (thread groove pump portion stator) provided on an outer periphery of the cylindrical rotary component, wherein a bounce back prevention means for preventing a particle from bouncing from the thread groove pump portion back toward the turbomolecular pump portion is provided downstream of the turbomolecular pump portion.