Roller Tappet Lubrication Bypass for Cam Durability
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Solution Overview
Problem
Engines with dry sumps experience inadequate lubrication at the top end, particularly affecting the cam and roller tappets, leading to increased friction and reduced durability due to point-like injection methods that fail to provide sufficient lubrication.
Innovation Solution
A roller tappet design featuring a lubricant supply groove and a second fluid communicating connection, such as a bypass or channel, that directs lubricant to a remote application point, including the cam surface, enhancing lubrication without additional pumps or re-designs, and allowing for retrofitting in existing engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If point-like injection method is used to supply lubricant to the top end of the engine, then the lubrication system remains simple, but the lubrication of cam and roller tappets is insufficient leading to increased friction and reduced durability
Solution Approach 1:
The lubricant supply system is segmented into multiple pathways: a first fluid communicating connection supplies lubricant to the roller reception space, while a second fluid communicating connection (bypass) directs lubricant to the cam surface. This segmentation allows targeted lubrication of both the roller and cam surfaces, reducing friction and improving durability without requiring a complete system redesign.
Solution Approach 2:
The roller tappet body acts as an intermediary structure that receives lubricant through the lubricant supply groove and distributes it to multiple locations via separate fluid communicating connections. The bypass channel serves as an intermediary pathway to deliver lubricant to the cam surface, enabling improved lubrication without adding external pumping or spray systems.
2Reliability
If additional pumps and spray units are installed to improve lubrication at the top end, then lubrication of cam and roller is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The roller tappet body is designed with multi-functionality: it not only receives and transmits lubricant to the roller but also incorporates bypass channels to supply lubricant to the cam surface. The existing lubricant supply groove and fluid communicating connections serve multiple purposes, eliminating the need for separate pumps and spray units while improving lubrication coverage.
Solution Approach 2:
The roller tappet structure itself provides the lubrication function for both the roller and cam surfaces through its integrated bypass channels. The system uses the existing lubricant supply infrastructure to serve additional lubrication needs without requiring external assistance from additional pumps or spray units, thereby maintaining system simplicity.
3Reliability
If existing roller tappets are replaced with new design featuring bypass channels, then lubrication is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into standard features (lubricant supply groove, tappet alignment groove) and the additional bypass channel. The bypass channel can be manufactured as a separate feature using standard machining operations, allowing the complex lubrication function to be added without requiring complete redesign of the manufacturing process.
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
Improves lubrication of the top engine components, reducing friction and increasing the durability of the roller tappet and cam, while maintaining efficient lubricant use and simplicity in manufacturing.
Implementation Method 1
a first fluid communicating connection is present between the lubricant supply groove for the reception and/or at least intermediate storage of lubricant, such as oil, and the roller reception space for the supply of lubricant
Implementation Method 2
a second fluid communicating connection is present in the roller tappet that is provided to guide some of the lubricant supplied to the lubricant supply groove to a second point of application, with the second point of application being remote from the outlet
Implementation Method 3
to increase the lubrication of the roller tappet and parts operatively connected thereto and hence to reduce the friction at the surface of a roller and to thereby increase a durability of the roller of the roller tappet
Data Source
Figure 1a~2
Figure 3a~3b
Figure 4a~4b
AI summary
The present invention relates to a roller tappet, the roller tappet comprising a body having a roller reception space that is formed at one end of the body and that is adapted to receive a roller, wherein the body further comprises a lubricant supply groove for the reception of lubricant and a tappet alignment groove, wherein a first fluid communicating connection is present between the lubricant supply groove and the roller reception space for the supply of lubricant to an outlet that opens into the roller reception space. The invention is characterized in that a second fluid communicating connection is present in the roller tappet that is provided to guide some of the lubricant supplied to the lubricant supply groove to a second point of application, with the second point of application being remote from the outlet. The invention further relates to a pump and to an engine respectively comprising at least one such tappet and to a method of lubricating a surface of a cam.