Motor Frame Flange Geometry to Prevent Stator Housing Breakage
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Solution Overview
Problem
Conventional electric rotating machines face issues with inadequate fastening of the stator outer cylinder to the stator core, leading to potential damage due to improper alignment and stress concentration, which can break the fastening flange and housing components.
Innovation Solution
The electric rotating machine design includes a fastening flange that inclines away from the outer circumferential surface of the cylinder portion, with a compression-direction stress applied to the root portion to prevent breakage, and a manufacturing method involving cutting machining and press-fitting of a water jacket to maintain alignment and reduce stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fastening flange is formed to incline toward the outer circumferential surface of the cylinder portion, then the alignment and fastening force between the frame and housing are improved, but tensile stress generated in the root portion of the fastening flange may break the flange and damage the frame
Solution Approach 1:
The patent inverts the inclination direction of the fastening flange compared to conventional designs. Instead of inclining toward the outer circumferential surface, the fastening flange is formed to incline toward the inner circumferential surface of the cylinder portion. This inversion changes the stress distribution so that compression stress acts on the root portion during fastening, preventing tensile stress-induced breakage while maintaining adequate fastening force.
2Manufacturing precision
If the first tab is formed more apart from the supporting member than the second tab, then the positioning accuracy of the housing to the supporting member is improved, but the first tab may be broken by tensile-component stress generated in the root portion during screw fastening
Solution Approach 1:
The patent inverts the relative positioning relationship between the first and second tabs. Instead of forming the first tab more apart from the supporting member, the first tab is formed closer to the supporting member than the second tab. This inversion ensures that during screw fastening, compression stress acts on the root portion of the first tab rather than tensile stress, preventing breakage while maintaining positioning accuracy.
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 prevents damage to the frame holding the stator core by managing stress distribution, ensuring high reliability and stability of the fastening mechanism.
Implementation Method 1
the fastening flange is formed in such a way as to incline toward a direction departing from the outer circumferential surface of the cylinder portion with respect to the radial direction of the cylinder portion, and it is configured in such a way that in a state where the fastening flange is fastened to the supporting member, compression-direction stress is generated on a root portion
Implementation Method 2
a water jacket that is fitted on the outer circumferential surface of the cylinder portion of the frame so as to form a cooling passage therein and is welded to the frame so that the cooling passage is sealed
Data Source
AI summary
An frame of an electric rotating machine has a cylinder portion that fits a stator core on an inner circumferential surface thereof, a fastening flange that protrudes from an axis-direction end portion of the cylinder portion toward the axis-direction outside of the cylinder portion and is fastened to a supporting member; the fastening flange is formed in such a way as to incline toward a direction departing from the outer circumferential surface of the cylinder portion with respect to the radial direction of the cylinder portion; it is configured in such a way that in a state where the fastening flange is fastened to the supporting member, compression-direction stress is generated on a root portion, at the outer-circumferential-surface side of the cylinder portion, of the fastening flange.