Vacuum Pump Spindle Bearing Mount with Helical Slots
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Solution Overview
Problem
Existing vacuum pump shaft bearing arrangements are either expensive due to high material mass or have low radial stiffness, and they lack reproducibility and stability over time.
Innovation Solution
A bearing mount arrangement for a vacuum pump shaft featuring a housing with a first bearing providing axial rigidity and a second roller bearing with a sleeve having helically arranged slots, allowing for adjustable axial and radial stiffness through geometry and material parameters, and potentially using lightweight materials like plastic or carbon fiber reinforced plastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elastic supports are formed from solid metallic material, then the bearing support has sufficient strength, but the mass becomes relatively large and production cost increases
Solution Approach 1:
The patent applies this principle by using a thin-walled sleeve with helical slots instead of solid metallic material. The sleeve wall thickness is specifically designed to be thin (e.g., 0.5-2mm) while maintaining sufficient strength through the helical slot geometry that provides elastic deformation capability. This resolves the contradiction by achieving both strength and weight reduction simultaneously.
Solution Approach 2:
The patent employs composite material principles by combining a thin-walled sleeve structure with elastic deformation characteristics. The helical slots create a composite-like behavior where the metal sleeve exhibits both structural integrity and elastic flexibility, effectively combining the benefits of rigid and flexible materials without requiring actual composite materials.
2Adaptability or versatility
If a slotted sleeve is used to decouple shaft outer diameter from roller bearing selection, then manufacturing flexibility improves, but the bearing support shows low radial stiffness and unstable behavior over time
Solution Approach 1:
The patent applies this principle by using helical (curved) slots instead of straight radial slots. The helical geometry provides progressive elastic deformation as the shaft expands or contracts, maintaining stable radial stiffness while still allowing the sleeve to accommodate different shaft diameters. The curved path of the helical slots distributes stress more evenly, preventing the instability issues seen in straight-slotted designs.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the helical slot geometry parameters (pitch, depth, width, and angle) to achieve the desired balance between adaptability and radial stiffness. By adjusting these parameters, the bearing support can be optimized for specific applications while maintaining stable behavior over time, resolving the contradiction between flexibility and reliability.
3Ease of operation
If multiple elastic elements are used to connect inner and outer rings, then bearing support flexibility improves, but the device complexity and production cost increase
Solution Approach 1:
The patent applies this principle by merging the functions of multiple separate elastic elements into a single integrated thin-walled sleeve with helical slots. The sleeve itself provides the elastic compliance through its slot geometry, eliminating the need for additional elastic elements, inner/outer rings, and their associated mounting structures. This significantly reduces device complexity while maintaining the required flexibility.
Solution Approach 2:
The patent employs universality by designing the thin-walled sleeve to perform multiple functions simultaneously: it provides structural support, accommodates shaft dimensional variations, provides elastic compliance, and serves as the mounting structure for the roller bearing. This multi-functionality eliminates the need for separate components, reducing complexity while maintaining operational flexibility.
Data Source
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AI summary
The invention relates to an arrangement for supporting a shaft (36) of a vacuum pump (10) with a housing (14), with a first bearing (44) which generates forces in the direction of the shaft axis and has axial stiffness, with a second bearing (42) which is designed as a rolling bearing and is arranged in a holder (46) with axial and radial stiffness, wherein the holder (46) has a sleeve (48), wherein the sleeve (48) has at least one slot (50, 52, 54) which is arranged helically in the sleeve (48).