Tappet Longitudinal Beam Bridge for Fuel Pump Load and Flow
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Solution Overview
Problem
Existing tappets for high-pressure fuel pumps face challenges with high loads, inadequate anti-rotation features, and poor medium flow due to thick disk-like bridge members, which increase mass and restrict fluid flow.
Innovation Solution
A tappet design featuring a thick-walled longitudinal beam bridge member with cylindrical segment-like surfaces and projections for anti-rotation, allowing partial filling and improved lubricant flow, while maintaining low mass and high load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick disk-like bridge member is used to increase load-bearing capacity, then the load resistance is improved, but the mass increases impermissibly and the medium flow is restricted
Solution Approach 1:
The bridge member is segmented into a longitudinal beam structure with web and flange portions, creating a hollow interior space. This segmentation maintains structural strength for load-bearing while reducing mass compared to a solid disk, and the hollow space enables medium flow through the tappet.
Solution Approach 2:
The bridge member features localized thickening at critical stress points (web and flange regions) to maintain load-bearing capacity, while the interior remains hollow for mass reduction and fluid flow. This local quality differentiation optimizes both strength and flow characteristics.
2Strength
If a thick disk-like bridge member is used to increase load-bearing capacity, then the load resistance is improved, but the medium flow is restricted
Solution Approach 1:
The bridge member is segmented into a longitudinal beam structure with web and flange portions, creating a hollow interior space. This segmentation maintains structural strength for load-bearing while reducing mass compared to a solid disk, and the hollow space enables medium flow through the tappet.
Solution Approach 2:
The bridge member features localized thickening at critical stress points (web and flange regions) to maintain load-bearing capacity, while the interior remains hollow for mass reduction and fluid flow. This local quality differentiation optimizes both strength and flow characteristics.
3Reliability
If a one-sided engagement of a lug through a clearance is used for anti-rotation, then the anti-rotation feature is provided, but it is inadequate for reliable fixation
Solution Approach 1:
The anti-rotation function is merged with the bridge member's structural geometry through the T-shaped cross-section. The transverse flange portion creates geometric engagement with the housing that inherently prevents rotation, eliminating the need for separate anti-rotation mechanisms and improving reliability.
Data Source
AI summary
A plunger (1) for a high-pressure fuel pump is proposed, having a housing (2) which is similar to a tube and in the drive-side annular face (3) of which two flats (5) lie diametrically opposite one another which are indented from an outer shell (4) of the housing (2) and in which a pin (7) is mounted which supports a roller, wherein an inner shell (8) of the housing (2) is penetrated axially below the roller by a separate bridge piece (9), the lower face (10) of which acts as a rest for a pump piston in the case of an output-side annular face (11) of the housing (2), wherein the bridge piece (9) is fixed against rotation about an axial line of the housing (2) and is configured as a thick-walled longitudinal beam, with the result that an area (13) in the manner of a cylindrical segment remains between the longitudinal walls (12) of said longitudinal beam and the inner shell (8) of the housing (2), wherein, in order to fix the bridge piece (9) against rotation about the axial line of the housing (2), in the circumferential section of the inner shell (8) of the housing (2), in a first transverse wall (14) of the bridge piece (9), at least one projection (15) protrudes from one of the components (8, 14), which projection (15) is seated in a respectively complementary recess (16) of the respective other one of the components (14, 8).