Hybrid Generator Rotor Support With Center Shaft Pre-Alignment
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Solution Overview
Problem
In series hybrid drivetrains, the rotor of the generator is not fully supported before coupling to the crankshaft, leading to potential damage to seals due to air gap contact, especially when access to the rear of the generator is limited.
Innovation Solution
A generator design with a center shaft supported by a first bearing in a bore and a support plate supported by a second bearing, providing cantilevered support to the rotor assembly, with a seal between the housing and hub, and a drive plate to transmit torque from the engine crankshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bearing is used to support the rotor in the generator, then the device complexity is reduced and cost is optimized, but the rotor is not fully supported before coupling to the crankshaft, leading to potential seal damage
Solution Approach 1:
The patent applies preliminary action by providing a temporary support structure (center shaft with bearing) that holds the rotor in proper position before the final coupling to the crankshaft occurs. This preliminary support prevents seal damage during assembly, and the support is removed once the crankshaft connection is established.
Solution Approach 2:
The center shaft acts as an intermediary element between the rotor and the final crankshaft connection. It provides temporary mechanical support and positioning during assembly, mediating the transition from unsupported to fully supported state without requiring complex permanent support structures.
2Stability of the object's composition
If conical surfaces with externally applied load are used to hold the rotor positioned during assembly, then the rotor positioning is maintained, but access to the rear of the generator is required to apply the load
Solution Approach 1:
Instead of applying load from the rear of the generator as in conventional solutions, the patent inverts the approach by providing support from the front side through the center shaft. This allows assembly operations to be performed from the accessible front side rather than requiring rear access.
Solution Approach 2:
The center shaft serves as an intermediary support structure that enables rotor positioning without requiring direct access to the rear of the generator. It mediates the positioning function in a location that is accessible during assembly operations.
3Ease of manufacture
If no mis-alignment compensation mechanism is provided, then the torque connection between ICE crankshaft and generator rotor is cost optimized, but the rotor is vulnerable to air gap contact and seal damage during coupling
Solution Approach 1:
The center shaft provides preliminary alignment and support action before the final torque connection is made. This preliminary positioning prevents harmful air gap contact and seal damage during the coupling process, while not requiring a permanent mis-alignment compensation mechanism in the final design.
Solution Approach 2:
The bearing-supported center shaft provides beforehand cushioning by maintaining proper rotor position and preventing contact with the stator during assembly. This protective action occurs before the potential harm of air gap contact can occur, eliminating seal damage risks.
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
Prevents seal damage by maintaining air gaps and ensuring proper alignment during coupling, enhancing durability and reducing mechanical stress.
Implementation Method 1
The center shaft can be supported for rotation by a first bearing in a bore of the center support
Implementation Method 2
The support plate can be supported for rotation by a second bearing on an outer diameter of the center support
Data Source
AI summary
A generator for a hybrid vehicle includes a housing including an end cover having an axially extending center support, a stator supported in the housing, a rotor assembly supported for rotation in the housing relative to the stator, and a center shaft coaxial with the rotor assembly. The center shaft is supported for rotation at a first axial position by the center support of the end cover, the center shaft extends axially from the center support and supports the rotor assembly at a second axial position, and the rotor assembly is supported at the first axial side of the generator by a support plate extending radially between a carrier of the rotor assembly and the center support of the housing.