Intermediate Shaft Bolt-Through Gearbox Cover for Mesh Alignment
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Solution Overview
Problem
The existing parallel axis gearboxes for electric axle gearboxes experience reduced axial stiffness near the intermediate shaft, leading to potential mesh misalignments and bearing misalignments due to deflections under load, which degrade gear and bearing durability.
Innovation Solution
A bolt is fixedly coupled through the longitudinal bore of the intermediate shaft to securely attach the cover to the housing, enhancing axial stiffness and reducing deflections, thereby minimizing mesh and bearing misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical fasteners are spaced around the outer perimeter of the cover to attach the cover to the housing, then the cover has increased axial stiffness near the mechanical fasteners, but the cover is less stiff in portions spaced apart from the mechanical fasteners, resulting in increased deflections under load
Solution Approach 1:
The fastening system is segmented into multiple locations: perimeter fasteners and a central fastener passing through the intermediate shaft. This segmentation distributes the stiffness enhancement to multiple critical areas, ensuring both perimeter stability and central alignment accuracy.
Solution Approach 2:
The intermediate shaft serves as an intermediary element that the central bolt passes through. This intermediary structure enables direct fastening at the critical central location without interfering with the perimeter fastening system, allowing independent optimization of both areas.
2Reliability
If the cover and housing contain and support the internal components of the gearbox, then the structure provides containment and support, but deflections in the cover under load result in mesh misalignments between the meshed gears
Solution Approach 1:
The support system is segmented into perimeter support (from outer fasteners) and central support (from the intermediate shaft fastener). This dual-segmented support structure prevents both peripheral distortion and central deflection, maintaining overall cover stability and gear alignment.
Solution Approach 2:
The additional central fastener acts as a preventive measure against load-induced deflections. By pre-establishing this rigid connection point at the most critical location (through the intermediate shaft), the system cushions against future misalignments before they occur.
3Ease of operation
If the intermediate shaft is positioned spaced apart from the outer perimeter of cover, then the intermediate shaft can rotate freely, but the cover has reduced axial stiffness under load near the intermediate shaft
Solution Approach 1:
The intermediate shaft serves as an intermediary structure that the central bolt passes through. This design allows the shaft to maintain its rotational freedom while simultaneously providing a rigid attachment path for the bolt, creating a dual-function element that resolves the stiffness-rotation tradeoff.
Solution Approach 2:
The intermediate shaft is nested within the cover structure, with the bolt passing through the shaft to connect to the housing. This nested arrangement allows the shaft to rotate independently within the cover while the bolt provides external structural support, combining rotational freedom with axial stiffness.
Data Source
AI summary
A parallel axis gearbox is provided for a vehicle. The parallel axis gearbox includes an input shaft having a first axis of rotation and an intermediate shaft having a second axis of rotation parallel to the first axis of rotation. The intermediate shaft includes an intermediate driving gear, an intermediate driven gear, and a longitudinal bore passing through the intermediate shaft. The intermediate driven gear is meshingly engaged with a first driving gear on the input shaft. The input shaft and the intermediate shaft are contained within and supported by a cover fixedly coupled to a housing. A bolt fixedly couples the cover to the housing and passes through the longitudinal bore of the intermediate shaft.