Electric Supercharger Thrust Bearing Redesign
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Solution Overview
Problem
Conventional motor-driven superchargers face issues with elongated shaft overhang and inadequate lubricating oil supply due to the placement of the electric motor between the thrust bearing and compressor impeller, leading to reduced rotation stability and oil distribution challenges.
Innovation Solution
The motor-driven supercharger incorporates a thrust bearing with a small-diameter disc-shaped thrust collar and separate turbine and compressor side thrust bearings, featuring a truncated conical structure and oil discharge paths to reduce shaft overhang and enhance lubrication, allowing for efficient oil supply and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric motor is provided between the thrust bearing and the compressor impeller, then the motor can assist acceleration at low speed, but the shaft overhang amount is enlarged leading to reduced rotation stability
Solution Approach 1:
The thrust bearing structure is redesigned by separating the thrust collar from the compressor impeller and positioning it at a different axial location. This spatial reconfiguration reduces the shaft overhang length while preserving the motor's acceleration assistance capability, thereby improving rotation stability without sacrificing power assistance.
2Force
If the thrust bearing is provided in the outer side of the radial bearing with the electric motor between them, then the thrust force can be supported, but the distance between thrust surfaces is long causing gap generation and inadequate lubricating oil supply
Solution Approach 1:
The thrust bearing is segmented into a separate thrust collar component that can be independently positioned. This segmentation allows the thrust surfaces to be placed closer together, reducing gaps and improving lubricating oil supply reliability while maintaining adequate thrust force support capability.
Solution Approach 2:
A dedicated thrust collar acts as an intermediary component between the thrust bearing and the compressor impeller. This intermediary element enables efficient load transfer and improves lubrication distribution by positioning the thrust surfaces optimally, ensuring reliable lubricating oil supply to the thrust interface.
3Ease of operation
If the shaft overhang amount is enlarged to accommodate the electric motor, then the motor can be installed, but the rotation stability is lowered at high speed
Solution Approach 1:
The thrust bearing components are repositioned in the axial dimension to reduce shaft overhang. This allows the electric motor to be installed while maintaining a shorter, more stable shaft configuration that supports high-speed rotation without compromising motor installation feasibility.
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 shortens the shaft overhang, improves lubrication distribution, and reduces part count and manufacturing costs while maintaining high-speed rotation stability and efficient oil discharge.
Implementation Method 1
a motor stator (24) fixed within a housing (16), and a motor rotor (22) rotationally driven by the motor stator (24)
Implementation Method 2
the thrust bearing (30) is constituted by a small-diameter disc-shaped thrust collar (32) rotating together with a turbine shaft (12), and a turbine side thrust bearing (34) and a compressor side thrust bearing (36) which block a movement in an axial direction of the thrust collar (32)
Data Source
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AI summary
A motor-driven supercharger is provided with a thrust bearing (30) rotatably supporting a thrust force applied to a turbine shaft (12). The thrust bearing (30) is constituted by a small-diameter disc-shaped thrust collar (32) rotating together with a turbine shaft, and a turbine side thrust bearing (34) and a compressor side thrust bearing (36) which block a movement in an axial direction of the thrust collar. The compressor side thrust bearing (36) has a small-diameter ring portion (37) including a thrust surface which is in contact with the thrust collar and has approximately an equal diameter, and a flange portion (38a) fixed to a housing (16) in the turbine side, and the small-diameter ring portion and the flange portion are arranged at different positions in an axial direction.