Tappet Arrangement Self-Alignment for High-Pressure Pump
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Solution Overview
Problem
High-pressure pumps in common rail injection systems face challenges in balancing durability and cost-effectiveness, particularly in downsized engine applications where space constraints require robust yet cost-efficient designs that often compromise on material selection and feature complexity.
Innovation Solution
A tappet arrangement with a roller and fixing mechanism that allows self-alignment within the pump housing, utilizing curved and flat side surfaces for rotation and limited movement, and a metallic fixing with elastic properties to reduce breaking torque and enhance alignment with the camshaft, thereby increasing robustness and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pump is downsized to fit smaller engine applications, then the pump size is reduced, but the space available for robust design and alignment tolerance is reduced
Solution Approach 1:
The tappet body is designed with curved side surfaces that allow it to dynamically self-align with the camshaft within a limited rotation range. This dynamic adjustment capability compensates for misalignment in downsized pump configurations without requiring larger tolerances or more complex alignment mechanisms.
Solution Approach 2:
The tappet arrangement performs self-alignment automatically through its curved side surfaces contacting the camshaft, eliminating the need for external alignment mechanisms or expensive precision adjustment features. The system self-corrects for misalignment within its designed rotation range.
2Reliability
If expensive materials and complex features are selected to ease internal stresses, then durability is improved, but manufacturing cost increases
Solution Approach 1:
The fixing component is designed as a simple, inexpensive metallic element with elastic properties that can be easily manufactured and replaced if needed. This simple component effectively reduces breaking torque and enables self-alignment without requiring expensive materials or complex features in other parts of the system.
Solution Approach 2:
The curved side surfaces of the tappet body change the geometric parameters of the contact interface, allowing limited rotation and self-alignment. This geometric parameter change enables the system to accommodate misalignment without requiring expensive materials or complex stress-relief features.
3Manufacturing precision
If the roller is constrained to prevent movement, then positioning precision is improved, but the ability to self-align and compensate for misalignment is reduced
Solution Approach 1:
The fixing component provides partial constraint by preventing excessive roller movement while allowing limited rotation of the tappet body. This partial action enables both precise positioning and self-alignment compensation within the designed rotation range, resolving the contradiction between constraint and adaptability.
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 solution enables a cost-effective and durable high-pressure pump design that self-aligns with the camshaft, compensating for misalignment and reducing the need for expensive materials, thus addressing the contradictions between durability and cost in downsized engine applications.
Implementation Method 1
The fixing is made from a metallic material with elastic properties, for example brass
Data Source
Figure 1~2
AI summary
A Tappet arrangement for a high pressure pump comprises: - a tappet body (101), - a roller (102) arranged partly in the tappet body (101), - a fixing (103) for holding the roller (102) in the tappet body (101) to prevent a movement of the roller (102) in direction of the longitudinal axis (R) of the roller (102), wherein the tappet body (101) comprises: - two curved side surfaces (104) arranged opposite to each other aligned in direction of the longitudinal axis (R) of the roller (102) for movable coupling the tappet arrangement with a pump housing (114) of the high pressure pump.