Captive Screw Nozzle Structure to Prevent Screw Loss
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Solution Overview
Problem
Existing solutions for retaining oil nozzles in internal combustion engines, such as using O-rings or foam glue, are costly and can decompose, releasing particles that affect engine performance and are not suitable for the automotive industry's requirements due to cramped engine spaces and risk of screw loss during mounting.
Innovation Solution
A captive screw nozzle design with a screw head cooperating with a holding member integral to the nozzle, forming a stop to retain the screw captive, utilizing a collar, groove, or clip to prevent screw loss and avoid additional parts, ensuring secure mounting without interference with tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If O-ring or foam glue is used to hold the retaining screw, then the screw is retained, but the cost increases and particles may be released affecting engine performance
Solution Approach 1:
The invention extracts and eliminates the O-ring or foam glue from the assembly by integrating the retaining function directly into the nozzle body through a captive screw design. The screw is permanently retained within the nozzle body via a retaining mechanism (such as a recess, deformation zone, or integrated feature), removing the need for separate retaining elements that could decompose and release particles into the engine environment.
Solution Approach 2:
The retaining function is merged with the nozzle body structure itself. The captive screw design integrates the screw, retaining mechanism, and nozzle body into a single unified component, eliminating separate retaining elements like O-rings or foam glue. This merging ensures the screw is permanently secured while avoiding materials that could decompose and release harmful particles.
2Reliability
If O-ring or foam glue is used to hold the retaining screw, then the screw is retained, but the cost increases
Solution Approach 1:
The retaining function is merged with the nozzle body structure, eliminating the need for separate O-rings or foam glue components. This integration reduces the total part count and eliminates the need to source, stock, and install additional retaining elements, thereby reducing manufacturing costs while maintaining reliable screw retention.
Solution Approach 2:
The nozzle body is designed to perform multiple functions: it delivers the lubricating oil or cooling fluid through the nozzle orifice, and simultaneously retains the screw through an integrated captive screw mechanism. This multi-functionality eliminates the need for separate retaining components, reducing overall assembly cost and complexity.
3Ease of operation
If the retaining screw is not captive, then assembly is simple, but the screw may be lost during mounting
Solution Approach 1:
The screw is pre-assembled and permanently retained within the nozzle body during manufacturing, forming a captive screw assembly. This preliminary action ensures the screw is securely held in place before the nozzle is installed in the engine, preventing screw loss during mounting operations while maintaining simple installation procedures.
Solution Approach 2:
The screw and nozzle body are merged into a single captive assembly through an integrated retaining mechanism. This merging ensures the screw cannot be lost during handling or installation, as it is permanently secured within the nozzle body structure, while the entire assembly remains simple to install as a single unit.
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3a~3b
AI summary
The invention relates to a captive screw nozzle (10) comprising a screw (30) for holding the nozzle (10) on a support, said screw (30) comprising a screw head (31) engaging with a holding member (20), secured to the nozzle (10), and forming a stop for retaining the captive screw (30) on the nozzle (10).