Fuel Injector Open/Close Element Welding Profile Integrity
Solution Overview
Problem
The production of balanced servo valves for fuel injectors faces challenges in precision fixing of stop elements and mounting an anchor in a slidable manner on a bushing, particularly with laser welding difficulties due to the external profile constraints.
Innovation Solution
A method for manufacturing an open/close element where the anchor is designed to perform a travel greater than the bushing, with a thin nonmagnetic lamina ensuring gap, and precise welding along a circumference of continuous contact to fix the intermediate body to the bushing without altering the external profile, reducing rebounds by controlled impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anchor is mounted in a slidable way on the bushing with precise stop elements, then the rebound control is improved, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The patent merges the anchor and bushing into a single monolithic component manufactured by selective laser melting. This eliminates the need for separate mounting operations, stop elements, and intermediate bodies, thereby reducing manufacturing complexity while maintaining the slidable mechanism and rebound control functionality through the integrated design.
Solution Approach 2:
The monolithic anchor-bushing component performs multiple functions simultaneously: it provides the slidable mechanism, contains the stop elements for precision positioning, houses the spring assembly, and controls rebounds. This multi-functionality reduces the number of separate parts and assembly steps while improving reliability.
2Strength
If laser welding is used to fix the intermediate body flange to the bushing, then the assembly is secured, but the external profile may be altered and manufacturing difficulties arise
Solution Approach 1:
The patent eliminates the need for laser welding by merging the intermediate body, flange, and bushing into a single monolithic component. This avoids the external profile alterations and manufacturing difficulties associated with welding while maintaining the structural strength and precision of the assembly through additive manufacturing.
3Reliability
If the anchor travel is made greater than the bushing travel, then rebound elimination is improved, but the device complexity increases
Solution Approach 1:
The patent integrates the differential travel mechanism directly into the monolithic anchor-bushing component. The anchor is designed with a greater travel range than the bushing, allowing it to strike against the bushing during rebound while maintaining a simple integrated structure without additional complexity.
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 method enhances the reliability and cost-effectiveness of the open/close element by minimizing rebounds and maintaining the external profile integrity, allowing precise alignment and reduced wear, thus improving the operational efficiency of the servo valve.
Implementation Method 1
said intermediate body being welded on said bushing along a circumference of continuous contact
Implementation Method 2
fixing of the flange by means of welding, for example laser welding
Data Source
Figure 1
Figure 2~6
Figure 4
AI summary
The manufacturing method regards an open/close element for balanced servo valves (5) of a fuel injector, wherein the open/close element (47) is fixed with respect to a bushing (41) designed to move for a certain travel for opening/closing the servo valve (5). The anchor (17) is axially movable for a travel greater than the travel of the open/close element (47) under the control of an electric actuator (15). The method comprises a step in which the bushing (41) is provided with a guide portion (61) designed to engage a hole (59) of the anchor (17) for a relative displacement with respect to the bushing (41), and a step in which an intermediate body (12a) is provided for supporting a spring (23) acting on the bushing (41); the intermediate body comprises a flange (24) and a connection pin (63). Then the anchor (17) is fitted on the guide portion (61), and the intermediate body (12a) is inserted into a seat (40a) in the bushing (41), with the flange (24) in contact with an end edge (66) thereof, and finally the intermediate body (12a) is welded to the guide portion (61) of the bushing (41) along a circumference (69) of continuous contact so that a continuous weld is obtained without any need for phasing with the welding device (70).