Rotor Core Convex Portion Stress Management
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Solution Overview
Problem
The existing rotor core designs experience stress concentration and unintended deformation due to tightening loads, leading to reduced interference between the rotor shaft and core when centrifugal forces are applied, causing the rotor core to widen.
Innovation Solution
The rotor core design includes a second hole group with inner peripheral walls featuring first and second arc points equidistant from the center and convex portions on the outer side, which alleviate stress concentration by deforming to absorb the tightening load, preventing unwanted deformation and maintaining interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tightening load of the rotor shaft is increased to secure adequate interference, then the interference between rotor shaft and rotor core is improved, but stress concentration occurs in the first annular portion causing unintended deformation
Solution Approach 1:
The patent applies local quality by creating a specific structural feature (convex portion with apex) in the first annular portion that concentrates deformation capacity to a localized area. This allows the majority of the rotor core to maintain its structural integrity while the convex portion locally absorbs stress through controlled deformation, preventing widespread unintended deformation while maintaining adequate interference fit.
Solution Approach 2:
The convex portion with its apex structure acts as a pre-designed stress absorption zone that cushions the first annular portion against stress concentration before damage occurs. This beforehand cushioning feature allows the rotor core to withstand tightening loads without experiencing unintended deformation that would compromise the interference fit between the rotor shaft and core.
2Stability of the object's composition
If the tightening load of the rotor shaft is reduced to prevent stress concentration, then deformation of the rotor core is suppressed, but the rotor core is pulled to the outer peripheral side by centrifugal force reducing interference
Solution Approach 1:
By localizing the deformation capacity to the convex portion, the patent allows the rest of the rotor core to maintain high structural stability. This means the rotor core can withstand centrifugal forces without being pulled outward, while the convex portion locally manages stress from tightening loads, preserving both deformation stability and interference strength simultaneously.
Solution Approach 2:
The pre-designed convex portion serves as a cushion that absorbs tightening stresses before they can cause harmful deformation. This allows the rotor core to maintain adequate interference fit without experiencing stress concentration, as the convex portion preemptively absorbs the stress that would otherwise reduce interference under centrifugal loading.
3Force
If holes of the second hole group are arranged to intersect with extension line of ribs, then tightening load is absorbed through ribs, but stress concentration occurs in the first annular portion
Solution Approach 1:
The convex portion with its apex acts as an intermediary element between the ribs and the first annular portion. It mediates the force transmission by providing a localized deformation zone that absorbs tightening loads transmitted through the ribs, preventing direct stress concentration in the first annular portion while maintaining effective load absorption capability.
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 effectively reduces stress concentration and prevents unintended deformation, allowing the rotor core to maintain adequate interference without reducing the tightening load, even under centrifugal forces.
Implementation Method 1
the stress concentration due to the tightening load of the rotor shaft can be alleviated by the deformation of the convex portion
Implementation Method 2
when the tightening load of the rotor shaft is reduced, the rotor core may be pulled to the outer peripheral side when a centrifugal force is applied
Data Source
AI summary
A rotor core includes: a rotor shaft hole into which a rotor shaft is press-fitted; a first hole group having a plurality of holes; a shaft holding portion; a second hole group having a plurality of holes; a first annular portion; and an electromagnetic portion having a plurality of magnet insertion holes. Each hole of the second hole group is arranged to intersect with an extension line of a rib formed between the adjacent holes of the first hole group. An inner peripheral wall of each hole of the second hole group includes: a first arc point and a second arc point being located on an arc equidistant from a center of the rotor core; and a convex portion having an apex portion on an outer side further than the arc. The apex portion is located between the adjacent holes of the first hole group in the circumferential direction.