Vacuum Pump Eccentric Rotor Sealing and Friction Reduction
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Solution Overview
Problem
Vacuum pumps with multiple vanes face challenges in sealing the cavity effectively against the environment due to multiple individual parts and friction surfaces, which hinders the generation of a strong vacuum.
Innovation Solution
The design incorporates a rotor that encloses the eccentric element of the central shaft, eliminating additional gaps and slots, and uses a positive coupling between the central shaft, rotor, and vane member to reduce friction and enhance sealing, with the vane member being guided by slots within the rotor rather than the cavity walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple vanes are used in the vacuum pump, then the pumping capacity is improved, but the sealing performance deteriorates due to multiple individual parts and friction surfaces
Solution Approach 1:
The patent combines multiple vanes into a single integrated vane member that rotates as one piece within the rotor. This merging eliminates the multiple separate sealing interfaces required by individual vanes, reducing leakage paths while maintaining the pumping capacity provided by the multi-vane configuration.
Solution Approach 2:
The single vane member performs multiple functions simultaneously: it creates the necessary vacuum sealing, transmits drive force from the eccentric element, and maintains the pumping capacity equivalent to multiple separate vanes. This multi-functionality resolves the contradiction by achieving both high productivity and reliable sealing through one component.
2Device complexity
If the vane is guided by cavity walls, then the structure is simple, but frictional losses increase and sealing is compromised
Solution Approach 1:
The patent introduces the rotor as an intermediary component between the vane member and the cavity walls. The rotor provides dedicated radial slots that guide the vane, eliminating direct contact with cavity walls. This intermediary structure reduces frictional losses and improves sealing while adding necessary complexity to achieve the performance benefits.
3Adaptability or versatility
If additional gaps and slots are present for the central shaft, then the design is more flexible, but sealing performance deteriorates
Solution Approach 1:
The patent nests the eccentric element and central shaft arrangement within the rotor structure. The rotor encloses the eccentric element and provides the necessary clearance and movement space, eliminating the need for additional external gaps and slots. This nesting maintains design flexibility while improving sealing by containing all necessary clearances within the rotor assembly.
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 improves the overall sealing of the vacuum pump, reduces frictional losses, and allows for effective vacuum generation by eliminating unnecessary sealing points and guiding surfaces, leading to a more stable and efficient operation.
Implementation Method 1
the rotor encloses radially the eccentric element of the central shaft... a rotational axis of the central shaft is offset from the rotational axis of the rotor and the point of action of the vane is offset from the rotational axis of the central shaft by means of the eccentric element on the central shaft
Implementation Method 2
The drivable vane member is typically movable to draw fluid into the cavity through the inlet and out of the cavity through the outlet... the vane is arranged in a radial slot of the rotor
Data Source
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AI summary
Vacuum pumpof the rotating vane type comprising: - a housing (4) defining a cavity (18) having an inlet and an outlet, - a drivable vane member (20) for a rotary driven movement inside the cavity (18), - a rotor (30) inside the cavity, - a rotatable central shaft (40) extending into the cavity, wherein the vane member (20) is coupled to the central shaft (40) by means of an eccentric element (42) on the central shaft, and slidably arranged in the rotor 30), the rotor (30) being rotatable together with said vane member (20) upon rotation of the vane member, wherein a rotational axis (AS) of the central shaft (40) is offset from the rotational axis (AR) of the rotor (30) and the point of action (AE) of the vane member (20) is offset from the rotational axis of the central shaft (40) by means of the eccentric element (42) on the central shaft (40), and wherein the rotor (30) encloses radially the eccentric element (42) of the central shaft (40).