Stator Assembly Ring Seal for Torsional Vibration Stiffness
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Solution Overview
Problem
The cantilevered stator design in electric machines of motor vehicles experiences high-energy, low-frequency vibrations due to torsional modes, leading to reduced mechanical resistance and uncomfortable acoustic noise, necessitating an increase in the stiffness of the embedding link between the stator and housing.
Innovation Solution
A stator assembly with a ring seal inserted axially between the stator body and the housing, utilizing a steel sheet with high elastic limit and specific radial portions to enhance stiffness, combined with threaded fastening mechanisms to solidly fasten the components, thereby increasing the embedding link's stiffness and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stator is cantilevered within the housing using conventional fastening means, then the assembly structure is simple and easy to manufacture, but the embedding link stiffness is insufficient resulting in high-energy low-frequency vibrations and reduced acoustic reliability
Solution Approach 1:
The ring seal is divided into two distinct radial portions: an inner radial portion positioned axially between the stator body and first fastening means, and an outer radial portion positioned axially between the first and second housing portions. This segmentation allows each portion to perform its specific sealing function independently while collectively increasing the embedding link stiffness to reduce vibrations.
Solution Approach 2:
The ring seal serves multiple functions simultaneously: it creates a seal between the inside and outside of the housing, increases the stiffness of the embedding link between the stator and housing, and provides structural support. This multi-functionality resolves the contradiction by improving acoustic reliability without proportionally increasing device complexity.
2Reliability
If a ring seal is added to increase embedding link stiffness, then acoustic and vibratory reliability improves, but the device complexity and number of components increases
Solution Approach 1:
The ring seal integrates multiple functions into a single component: sealing between housing interior and exterior, sealing between stator body and fastening means, and structural reinforcement to increase embedding link stiffness. By merging these functions into one piece rather than using separate components, the invention improves acoustic reliability while minimizing the increase in device complexity.
Solution Approach 2:
The ring seal serves multiple functions simultaneously: it creates a seal between the inside and outside of the housing, increases the stiffness of the embedding link between the stator and housing, and provides structural support. This multi-functionality resolves the contradiction by improving acoustic reliability without proportionally increasing device complexity.
3Reliability
If the axial offset between the inner and outer radial portions is reduced to less than 3 mm, then the bearing planes are brought closer together maximizing stiffness contribution, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a parameter range for the axial offset between the inner and outer radial portions (less than 3 mm) that optimizes the stiffness contribution of the ring seal. This parameter change balances the need for high embedding link stiffness with practical manufacturing capabilities, resolving the contradiction between reliability improvement and manufacturing precision requirements.
Data Source
AI summary
A stator assembly for an electric machine includes a first housing portion, a second housing portion, a stator body inserted into at least the first housing portion, a link for rotatably linking the stator body with the first housing portion, a first attachment for attaching the stator body to the first housing portion, and a second attachment for attaching the two housing portions to one another. The assembly includes an annular seal inserted axially between the stator body and the first attachment as well as between the two housing portions.