Rotating Electric Machine Stator Press-Fit Vibration Control
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Solution Overview
Problem
The existing rotating electric machines, particularly electric power steering motor devices, face challenges in downsizing due to the increased size caused by the intermediate member between the stator and motor frame, which also fail to effectively suppress vibrations during operation.
Innovation Solution
A rotating electric machine design where the intermediate member is press-fitted to the outer peripheral surface of the stator core, providing a higher stiffness per unit length than the tubular portion, allowing for improved radial tightening force on the stator core and reduced plate thickness of the motor frame, thereby achieving downsizing and vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate member is provided between the stator and motor frame, then the tightening force on the stator core is improved and vibrations are suppressed, but the device size increases
Solution Approach 1:
The intermediate member is integrated with the motor frame to form a unified structure, eliminating the need for separate components while maintaining the tightening function. The intermediate member and motor frame are combined into a single press-fit assembly that secures the stator core without increasing overall device volume.
Solution Approach 2:
The stiffness of the intermediate member per unit length is optimized to be higher than that of the tubular portion, creating an asymmetric stiffness distribution that effectively suppresses vibrations while minimizing the space required for the intermediate member.
2Volume of moving object
If the plate thickness of the tubular portion is reduced for downsizing, then the device size decreases, but the structural strength and vibration suppression capability deteriorate
Solution Approach 1:
The stiffness of the intermediate member per unit length is designed to be higher than the stiffness of the tubular portion per unit length. This parameter optimization allows the tubular portion to have reduced plate thickness while the intermediate member compensates for the reduced stiffness, maintaining overall structural strength and vibration suppression capability.
Solution Approach 2:
The motor frame combines the tubular portion and intermediate member into a composite structure where each component has optimized properties. The intermediate member provides high stiffness in specific regions, allowing the tubular portion to use thinner material while maintaining overall structural integrity.
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
The design effectively suppresses vibrations and noise while enabling downsizing of the rotating electric machine by enhancing the radial tightening force and reducing the plate thickness of the motor frame, maintaining structural integrity and reducing manufacturing costs.
Implementation Method 1
an intermediate member, which is provided on an outer peripheral surface of the stator core in the radial direction, and is held in a state of being press-fitted to an inner peripheral surface of the tubular portion in the radial direction
Data Source
AI summary
To obtain a rotating electric machine capable of suppressing vibrations generated at the time of driving and achieving downsizing. The rotating electric machine includes: a rotor; a stator including a stator core provided on an outer side with respect to the rotor in a radial direction of the rotor; a motor frame, which includes a tubular portion provided on an outer side with respect to the stator core in the radial direction, and has the stator fixed thereto; and an intermediate member, which is provided on an outer peripheral surface of the stator core in the radial direction, and is held in a state of being press-fitted to an inner peripheral surface of the tubular portion in the radial direction, wherein a stiffness of the intermediate member per unit length is higher than a stiffness of the tubular portion per unit length.