Camshaft Thrust Surface Lubrication via Cored Bulkhead Channels
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Solution Overview
Problem
The increased axial thrust loads from valve timing control devices in internal combustion engines pose challenges to the lubrication of camshaft thrust surfaces, leading to excessive wear, and existing solutions are costly to implement.
Innovation Solution
The camshaft system incorporates surface-piercing, radially extending lubricant distribution channels in the bulkhead thrust surfaces, which are cored during casting, ensuring lubricant distribution to both camshaft and bulkhead thrust surfaces without additional machining costs, thereby enhancing lubrication and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lubrication methods are used for camshaft thrust surfaces, then manufacturing cost is reduced, but excessive wear occurs on thrust surfaces due to increased axial thrust loads from valve timing control devices
Solution Approach 1:
The lubricant distribution channels are cored during the casting process itself, before the bulkhead thrust surfaces are machined. This preliminary action incorporates the lubrication system into the base structure during manufacturing, eliminating the need for additional costly machining operations to create separate lubrication channels, while ensuring proper lubricant delivery to prevent thrust surface wear
Solution Approach 2:
Surface-piercing lubricant distribution channels are created specifically in the bulkhead thrust surfaces where lubrication is most needed. The channels are radially extending and positioned to deliver lubricant directly to the camshaft thrust surfaces, providing localized enhanced lubrication precisely where the axial thrust loads cause excessive wear, without requiring complex modifications elsewhere in the system
2Reliability
If additional machining operations are performed to create lubrication channels, then lubrication quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The lubrication channel creation process is merged with the casting process. The channels are cored out during casting, combining two manufacturing operations into one. This integration ensures that the lubrication system is built-in from the start, providing high-quality lubrication delivery without requiring separate, complex machining operations afterward, thereby reducing manufacturing process complexity while maintaining lubrication effectiveness
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
This solution provides enhanced lubrication to camshaft thrust surfaces, preventing premature wear and maintaining the cost-effectiveness and robustness of the camshaft system, while eliminating the need for additional machining operations.
Implementation Method 1
The camshaft bearing, including the thrust bearing, is supplied with lubricant by means of a lubricant supply passage extending through at least a portion of the camshaft... oil flowing into the parent camshaft bearing will be caused to be deposited upon a bulkhead thrust surface, as well as upon the camshaft thrust surface
Data Source
AI summary
A cylinder head for an internal combustion engine includes a casting having a number of camshaft support bulkheads. Each of the support bulkheads has a portion of a parent bore bearing for mounting a camshaft. A bulkhead thrust surface is formed in an outer surface of at least one of the support bulkheads. A camshaft is rotatably mounted upon the support bulkheads. The camshaft has at least one thrust bearing member abutting a bulkhead thrust surface which is provided with lubricating oil by means of a radially extending, surface-piercing lubricant distribution channel formed in the bulkhead thrust surface, such that oil flowing in the parent bearing will be caused to be deposited upon the bulkhead thrust surface as well as upon the camshaft thrust surface.