Timing Wheel Cutouts for Camshaft Phaser Torsional Coupling
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Solution Overview
Problem
Existing camshaft phaser arrangements for concentric camshaft assemblies face challenges in monitoring inner and outer camshaft positions while minimizing packaging space, especially in single camshaft configurations that actuate both intake and exhaust valves.
Innovation Solution
A camshaft phaser arrangement featuring a first and second camshaft phaser, each connected to either the inner or outer camshaft, with at least one timing wheel that includes cutouts for a coupling and apertures for error-proofing, allowing for torsional coupling and optimized packaging, and incorporating orientation guides for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stacked coaxial camshaft phasers are used for concentric camshaft assembly, then independent phasing of inner and outer camshafts is achieved, but packaging space is increased
Solution Approach 1:
The patent implements nesting by placing the second camshaft phaser inside the hollow interior of the first camshaft phaser, with the second phaser's rotor nested within the first phaser's stator. This nested arrangement allows both phasers to be stacked coaxially in a compact configuration, achieving independent phasing of inner and outer camshafts while minimizing packaging space. The coupling mechanism is arranged to torsionally couple the phasers through the nested structure.
Solution Approach 2:
The patent transitions from a radial arrangement to a stacked coaxial arrangement by utilizing the axial dimension. Instead of placing phasers side-by-side radially, the design stacks them coaxially in the axial direction, with the second phaser positioned within the hollow space of the first phaser. This dimensional change enables compact packaging while maintaining independent phasing capability.
2Ease of operation
If timing wheel with cutouts is used to accommodate coupling, then torsional coupling is enabled, but manufacturing precision requirements are increased
Solution Approach 1:
The timing wheel incorporates asymmetric cutouts with specific angular spans that accommodate the torsional coupling mechanism. The cutouts are positioned at specific angular locations rather than being symmetrically distributed, allowing the coupling to engage properly while maintaining manufacturing feasibility. The asymmetric design ensures proper alignment and torsional flexibility without requiring extremely tight tolerances.
Solution Approach 2:
The cutouts in the timing wheel are designed with angular spans that are equal to or greater than the range of authority of the camshaft phaser. This excessive action ensures that the coupling can accommodate the full range of motion required for independent phasing, providing a margin of error in manufacturing while maintaining the necessary torsional coupling capability.
3Reliability
If multiple apertures for error-proofing are added to timing wheel, then assembly reliability is improved, but device complexity is increased
Solution Approach 1:
The timing wheel features multiple apertures arranged in a pattern that creates an error-proofing mechanism. These apertures are positioned at specific locations that allow only correct assembly orientation, effectively copying the orientation guide function through the aperture pattern. This design ensures proper assembly without requiring complex orientation guides or additional fastening mechanisms.
Solution Approach 2:
The multiple apertures in the timing wheel serve multiple functions: they provide structural attachment points for fasteners, create the error-proofing pattern for proper orientation, and work in conjunction with the cutouts to enable torsional coupling. This multi-functionality reduces the need for separate components, maintaining reliability while limiting complexity increase.
Data Source
AI summary
A camshaft phaser arrangement configured for a concentric camshaft assembly having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser, a second camshaft phaser, a coupling, and at least one timing wheel connected to at least one of the first or second camshaft phaser. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. The at least one timing wheel defines at least one cutout that is configured to receive at least a portion of the coupling.