Flexible Gear Retainer Centering in Electric Camshaft Phasers
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Solution Overview
Problem
Existing electric camshaft phaser assemblies face issues with flexible gears becoming off-centered and jamming due to excessive torque, leading to tooth sticking and inefficiencies in phasing the camshaft and crankshaft.
Innovation Solution
The implementation of a flexible gear with a retainer and a centering feature, such as a groove, in the output gear to maintain the flexible gear's elliptical orientation and prevent off-centering, ensuring proper engagement with the output gear teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a flexible gear is used to transmit torque in an electric camshaft phaser assembly, then torque transmission capability is improved, but the flexible gear becomes off-centered and jams under excessive torque
Solution Approach 1:
A retainer component is introduced as an intermediary element between the flexible gear and the output gear. The retainer includes a centering feature that engages with a corresponding feature on the output gear, acting as a mediator to maintain proper alignment and prevent off-centering of the flexible gear during torque transmission
Solution Approach 2:
The solution adds a new dimensional constraint by introducing axial centering features that extend in the axial direction. The retainer's centering feature protrudes axially to engage with the output gear, creating a constraint in the axial dimension that prevents radial off-centering of the flexible gear
2Adaptability or versatility
If the flexible gear is deformable into an elliptical orientation, then phasing adjustment capability is improved, but the gear becomes prone to tooth sticking and jamming
Solution Approach 1:
The retainer acts as an intermediary that maintains proper tooth alignment between the flexible gear and output gear. By providing axial centering, it ensures that teeth engage smoothly during the elliptical deformation cycle, preventing sticking and jamming while allowing full phasing adjustment range
3Reliability
If a retainer with centering feature is added to the flexible gear, then gear centering stability is improved, but device complexity increases
Solution Approach 1:
The retainer is merged with the flexible gear as an integrated component rather than a separate part. The centering feature is formed as part of the retainer structure, combining multiple functions (retention and centering) into a single component to minimize overall device complexity
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
The solution effectively prevents the flexible gear from becoming off-centered, thereby preventing tooth jamming and ensuring smooth phasing of the camshaft and crankshaft, enhancing the assembly's operational efficiency and reliability.
Implementation Method 1
a flexible gear deformable into an elliptical orientation for engaging the output gear to transmit torque from the sprocket to the output gear; and a wave generator for deforming the flexible gear into the elliptical orientation
Data Source
AI summary
A camshaft phaser assembly configured for phasing a camshaft and a crankshaft with respect to each other is provided. The camshaft phaser assembly includes a sprocket for receiving torque from the crankshaft; an output gear for driving the camshaft; a flexible gear deformable into an elliptical orientation for engaging the output gear to transmit torque from the sprocket to the output gear; and a wave generator for deforming the flexible gear into the elliptical orientation; the flexible gear radially disposed about the wave generator and including an inner circumferential surface in contact with an outer race of the wave generator, the flexible gear including teeth for engaging the output gear in the elliptical orientation and a retainer at an axial end of the flexible gear, the output gear including a centering feature configured for contacting the retainer to center the flexible gear in the elliptical orientation inside of the output gear.