Fuel Pump Shoe Apertures for Lubrication and Wear
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Solution Overview
Problem
High pressure fuel pumps experience fatigue wear in the shoe component due to inadequate lubrication, which reduces their service life, and existing solutions do not effectively address this issue.
Innovation Solution
The design incorporates apertures and channels in the shoe and shoe guide to create fluid pathways that enhance lubricant flow and hydrodynamic lubrication between the shoe, follower roller, and cam components, reducing sliding friction and improving lubrication circulation within the pump assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shoe design without apertures is used, then the structure is simple, but fatigue wear occurs due to inadequate lubrication
Solution Approach 1:
The shoe is segmented by introducing apertures that divide the shoe body into regions that allow lubricant flow paths, creating channels for lubricant circulation between the upper and lower sides of the shoe without completely separating the structure
Solution Approach 2:
The shoe design incorporates local quality changes by adding apertures in specific locations where lubrication is most needed, particularly at the interface between the shoe and follower roller, while maintaining the structural integrity of other regions
2Reliability
If apertures are added to improve lubrication, then fatigue life increases, but manufacturing complexity increases
Solution Approach 1:
The aperture design allows for parameter optimization in terms of size, shape, and location to balance lubrication effectiveness with manufacturing ease, enabling the apertures to be formed using standard machining or molding processes
3Reliability
If lubricant flow is enhanced through apertures, then hydrodynamic lubrication improves, but friction and wear reduction requires optimized flow paths
Solution Approach 1:
The apertures are positioned to allow lubricant to reach the contact areas between the shoe and follower roller in advance, ensuring that lubrication is established before significant wear can occur
Solution Approach 2:
The apertures act as intermediaries that facilitate the transfer of lubricant from the bulk lubricant supply to the critical contact interfaces, enabling improved lubrication without requiring direct modification of the contact surfaces
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 design significantly increases the fatigue life of the shoe and overall robustness of the high pressure fuel pump by reducing friction and improving pressure stability through enhanced lubrication, leading to improved performance and durability.
Implementation Method 1
the at least one aperture can improve hydrodynamic lubrication at the interface between the shoe and the follower roller
Implementation Method 2
sliding friction can be reduced to increase the fatigue life of the shoe
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a high pressure fuel pump assembly (1) for an internal combustion engine. A follower roller (39) is provided for engaging a cam (41) provided on a rotatable driveshaft (43). A shoe (19), which is guided in a shoe guide (21) having a guide face (55), cooperates with the follower roller (39) for reciprocating a fuel pump plunger (3). The shoe (19) has an upper side (25) and a lower side (27); a part cylindrical recess (37) being formed on the lower side (27) for cooperating with the follower roller (39). At least one aperture (57, 59; 59'; 59", 61; 63) is provided in the shoe guide (21) and/or the shoe (19) to form at least one fluid pathway for maintaining fluid communication between the upper and lower sides (25, 27) of the shoe (19). The present invention also relates to a shoe (19) and a shoe guide (21).