Stepped Rotor Camshaft Phaser Locking Pin
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Solution Overview
Problem
Camshaft phasers in internal combustion engines experience oil leakage and oscillation during engine start-up due to lack of oil pressure, leading to noise and potential damage, and existing solutions like locking pins are not optimized for weight and size reduction.
Innovation Solution
A camshaft phaser design with a base portion having increased diameter steps for a locking pin assembly and reduced diameter sections, allowing for a locking pin to secure the rotor in place during startup and enabling efficient oil pressure utilization, while reducing material usage and increasing vane surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking pin assembly is added to prevent oscillation during startup, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking pin assembly is integrated into the rotor assembly by forming the pin within the rotor material itself, combining the rotor and locking mechanism into a single unified component. This eliminates the need for separate locking pin components while maintaining the oscillation prevention function during startup.
Solution Approach 2:
The rotor serves multiple functions: it acts as both the rotating component that transmits camshaft timing and as the housing for the integrated locking pin assembly. The single rotor structure performs both timing transmission and startup protection functions, reducing overall device complexity.
2Weight of moving object
If the rotor base portion is reduced in material usage, then weight is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The rotor base portion is segmented into distinct radial sections with different diameters: a first radial section with a first diameter and a second radial section with a second diameter. This segmentation allows optimization of material distribution, placing material only where structurally necessary while reducing overall weight.
Solution Approach 2:
Different radial sections of the rotor base portion have different local properties (different diameters) optimized for their specific functional requirements. The varying diameter profile provides structural integrity where needed while minimizing material usage in less critical areas, achieving weight reduction without compromising overall precision.
3Volume of moving object
If the rotor is reduced in size, then device size is reduced, but the locking pin assembly may not fit properly
Solution Approach 1:
The rotor base portion is divided into radial sections with varying diameters, creating a stepped profile that provides discrete locations for locking pin assembly integration. The first and second radial sections with different diameters create natural mounting zones that accommodate the locking pin assembly within a compact overall rotor volume.
Solution Approach 2:
The locking pin assembly is positioned in the radial dimension rather than requiring axial or circumferential space. By utilizing the radial depth of the rotor base portion, the design accommodates the locking mechanism without increasing the rotor's overall external dimensions, maintaining compact size while enabling proper assembly.
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 design effectively prevents oscillation and noise during engine start-up, reduces weight and size, and enhances operational efficiency by allowing precise control of cam lobe timing and fuel savings.
Implementation Method 1
a locking pin assembly bore formed through said base portion at said increased diameter step
Implementation Method 2
The vane-cell type phaser, in particular, employs a supply of hydraulic fluid, normally engine oil, to opposing chambers in the phaser in order to shift the vanes within the phaser circumferentially
Implementation Method 3
An increased step diameter of the rotor base portion relative to the remaining minor diameter of the rotor base portion is formed over at least one circumferential section between the protruding vanes
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A rotor (7) for a camshaft phaser (1) assembly for an internal combustion engine. The rotor (7) includes a base portion (38) from which protrudes a plurality of vanes (14) spaced over the circumference of the base portion (38) of the rotor (7). An increased diameter stepped portion (32) of the base portion (38) of the rotor (7) is provided over at least one section between at least two of the protruding vanes (14). The increased diameter portion (32) allows for insertion of at least one locking pin assembly (4,5) within the base portion of the rotor (7), reducing the remaining rotor base portion diameter to at least reduce material weight and size of the camshaft phaser assembly.