Swing Rotor Branch Arm Thinning for Centrifuge Stress Relief
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Solution Overview
Problem
The increasing size and weight of centrifuge buckets lead to stress concentration near the base of the holding pins, causing deformation and reducing the lifespan of the swing rotor, and existing solutions fail to adequately manage this issue without increasing manufacturing costs.
Innovation Solution
The design includes a thickness-reduced part surrounding the holding pins, with branch arms that diverge at a predetermined angle and a connection part that allows for controlled deformation, reducing stress concentration and maintaining a uniform gap between the holding pins and buckets to prevent vibration and stabilize the centrifugal separation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bucket size is increased to process larger sample volumes, then the productivity is improved, but the weight of the bucket increases causing greater stress concentration near the holding pin base
Solution Approach 1:
The patent applies local quality by creating a thickness-reduced part (local thinning) at the specific location where the branch arm connects to the holding pin. This localized structural modification allows the branch arm to deform more easily at the connection point, distributing the stress from heavier buckets away from the holding pin base and preventing stress concentration while maintaining overall structural integrity.
2Reliability
If the holding pin shape is modified to reduce stress concentration, then the reliability is improved, but the manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent segments the branch arm structure by introducing a thickness-reduced part that separates the holding pin connection region from the main branch arm body. This segmentation allows the connection region to have different structural characteristics (reduced thickness for flexibility) while the main body maintains its original manufacturing precision and strength, thus improving reliability without compromising manufacturing precision.
3Strength
If a reinforcing part is added around the concave part of the bucket, then the strength is improved, but the device complexity increases
Solution Approach 1:
The patent merges the reinforcing function into the existing branch arm structure by creating a thickness-reduced part that is integrated with the branch arm. Instead of adding a separate reinforcing part around the bucket, the structural reinforcement is achieved through the modified branch arm geometry itself, which provides the necessary support while maintaining a simpler overall device structure.
4Stability of the object's composition
If the gap between the holding pin and bucket is reduced to prevent vibration, then the stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies dynamics by making the branch arm flexible through the thickness-reduced part, allowing it to deform and adapt to the bucket position during rotation. This dynamic adaptation maintains a uniform gap between the holding pin and bucket throughout the centrifugal separation process, ensuring stability without requiring extremely tight manufacturing tolerances for the gap.
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 alleviates stress concentration near the holding pin base, improves the rotor's lifespan, and maintains the stability of the centrifugal separation operation, allowing for increased bucket capacity without excessive deformation or vibration.
Implementation Method 1
When the swing rotor body rotates at a high speed, the holding pins are slightly deformed by the centrifugal force they receive from the bucket
Implementation Method 2
The branch arm deforms in a state substantially perpendicular to the holding pin, such that the stress concentration near the convex part base of the holding pin can be alleviated
Data Source
AI summary
Provided is a swing rotor for a centrifuge. The centrifuge includes a swing type rotor body having a plurality of holding pins and a plurality of buckets held by the holding pins in a swingable manner. On the rotor body, a connection part is formed to connect two branch arms that diverge from an arm part on an outer peripheral side. A thickness-reduced part penetrating in the same direction as a driving shaft is formed in a region surrounded by the two branch arms on an inner peripheral side of the connection part. Since the branch arms deform accordingly to a certain extent, partial concentration of the stress applied on the holding pins due to a centrifugal load can be alleviated. Thus, the lifespan of the centrifuge can be improved and the centrifugal separation operation can be stabilized.