Electric Compressor Stator Holder Vibration and Heat Management
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Solution Overview
Problem
Existing electric compressors for turbochargers face issues with noise generation due to vibration and inadequate heat dissipation, particularly at high rotational speeds, as the stator and housing contact through a thermally conductive resin, which does not effectively reduce vibration or dissipate heat.
Innovation Solution
A configuration where the stator holder is fixed to the housing only at the central axis direction, creating a gap in the radial direction to reduce vibration transmission and allowing direct heat conduction, with a low-rigidity part between the fixing and holder body parts to attenuate vibrations, and a filler to enhance thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the stator is contacted with the housing through a thermally conductive resin, then heat transmission is improved, but vibration transmission to the housing increases causing noise
Solution Approach 1:
The stator holder is divided into a first end portion (fixed to housing) and a second end portion (gap from housing), with a low-rigidity intermediate portion connecting them. This segmentation allows heat conduction path separation from vibration transmission path, enabling heat dissipation while reducing noise.
Solution Approach 2:
Different portions of the stator holder have different rigidity characteristics: the first end portion has high rigidity for heat conduction, the low-rigidity intermediate portion has reduced rigidity for vibration attenuation, and the second end portion has high rigidity for structural support. This local quality differentiation resolves the contradiction between heat dissipation and noise reduction.
2Productivity
If the rotational speed of the electric motor is increased to 10,000 rpm or more, then compressor performance is improved, but noise from housing vibration increases significantly
Solution Approach 1:
The low-rigidity intermediate portion of the stator holder is designed to attenuate mechanical vibrations generated by the high-speed rotor. By providing a compliant connection that isolates the housing from vibration, the system can operate at 10,000 rpm or more without excessive noise from housing vibration.
3Object-generated harmful factors
If the stator holder is fixed to the housing only at the first end in the central axis direction, then vibration transmission is reduced, but heat dissipation may be insufficient
Solution Approach 1:
The low-rigidity intermediate portion acts as an intermediary element between the fixed first end and the free second end of the stator holder. It provides a compliant connection that transmits heat effectively while attenuating vibration, serving as a mediator that reconciles the conflicting requirements of vibration isolation and heat dissipation.
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 effectively reduces noise and enhances heat dissipation in electric compressors by minimizing vibration transmission and improving thermal conductivity, thereby addressing the limitations of previous designs.
Implementation Method 1
the low-rigidity part provided between the fixing part and the holder body part has lower rigidity than the fixing part and the holder body part, when the holder body part vibrates due to vibration transmitted from the stator, the low-rigidity part elastically deforms. Due to elastic deformation of the low-rigidity part, vibration of the stator is attenuated
Implementation Method 2
Due to elastic deformation of the low-rigidity part, vibration of the stator is attenuated, and vibration transmitted to the fixing part can be reduced
Implementation Method 3
since the stator holder is fixed to the housing at a part in the central axis direction, heat can be directly conducted to the housing from the stator through the stator holder
Data Source
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AI summary
An electric compressor (10) includes a compressor unit (11) configured to compress air and a motor unit (20) configured to drive the compressor unit (11). The motor unit (20) includes a housing (21) that forms an outer frame of the motor unit (20), a rotor (22) that is provided in the housing (21) and rotatably supported around a central axis O, a stator (23) that is disposed radially outward from the rotor (22), and a stator holder (30) which is fixed to the housing (21) only in a part in a central axis O direction and is provided such that there is a gap in a radial direction crossing the central axis O between it and an inner circumferential surface of the housing (21) in the rest in the central axis O direction and inside which the stator (23) is accommodated.