Electric Compressor Inverter Housing Layout for Radial Expansion
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Solution Overview
Problem
Existing inverter-integrated electric compressors face design flexibility limitations due to the need for machining grooves on the outer surface of the inverter case, which can interfere with other structures and restrict the expansion of the inverter case.
Innovation Solution
The electric compressor design includes a cylindrical first connection part on the motor housing and a cylindrical second connection part on the inverter housing, where the outer surface of the first connection part forms grooves for O-rings, allowing for sealing without the need for machining on the outer surface of the inverter case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove is formed on the outer circumferential surface of the protrusion of the inverter case to secure the O-ring, then refrigerant leakage is suppressed, but the inverter case cannot be expanded outward in the radial direction due to machining device interference
Solution Approach 1:
Instead of forming the groove on the outer circumferential surface of the inverter case protrusion (which requires radial machining access), the groove is formed on the inner circumferential surface of the housing. This inversion of the groove location allows the inverter case to be expanded radially without interfering with the machining device, while still achieving reliable refrigerant sealing through the O-ring secured in the inverted groove location.
2Volume of stationary object
If the inverter case is expanded outward in the radial direction to increase internal volume, then the inverter case volume increases, but the expansion is blocked by interference with the machining device
Solution Approach 1:
The groove is relocated from the outer circumferential surface to the inner circumferential surface of the housing, inverting the traditional groove placement. This allows the inverter case to be expanded radially to increase internal volume without the expanded portion interfering with the machining device that forms the groove on the housing's inner surface.
Solution Approach 2:
The groove formation is shifted from requiring radial access (outer surface machining) to requiring axial or internal access (inner surface machining). This dimensional change in the groove location allows radial expansion of the inverter case while maintaining manufacturability of the groove through alternative machining approaches.
3Volume of stationary object
If the axial length of the inverter case is increased to increase internal volume, then the inverter case volume increases, but the overall size of the electric compressor increases
Solution Approach 1:
Instead of increasing volume by extending the inverter case axially (which increases overall compressor length), the design enables radial expansion of the inverter case. The groove is formed on the inner circumferential surface of the housing, allowing the inverter case to protrude radially outward and increase internal volume without increasing the axial length of the electric compressor.
Data Source
AI summary
An object is to improve design flexibility. An electric compressor includes: a motor configured to drive a scroll compression mechanism that compresses a refrigerant; an inverter configured to drive the motor; a housing filled with the refrigerant and accommodating the motor; and a lower case connected to the housing, which is aligned with the lower case in the axial direction, and accommodating the inverter. The housing has a cylindrical first connection part centered on the center axis extending in the axis direction. The lower case has a cylindrical second connection part centered on the center axis extending in the axial direction. The outer circumferential surface of the first connection part and the inner circumferential surface of the second connection part are in contact with each other.