Banjo Assembly Segmented Bolt Conical Thread Sealing
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Solution Overview
Problem
Existing banjo assemblies face issues such as unstable connections, difficulty in rotating the banjo body, potential for leaks due to tight screwing requirements, and the need for permanent fixation which makes removal and replacement complicated and costly.
Innovation Solution
A banjo assembly with a two-part banjo bolt featuring a conical threaded coupling part that forms a leak-free and secure connection without requiring deep screw holes, allowing for easy assembly and disassembly, and utilizing axially slidable radial sealing rings for a play-free and robust fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the banjo bolt is screwed into the screw hole far enough to compress the axial sealing rings and prevent fuel leakage, then sealing reliability is improved, but the banjo body becomes difficult to rotate to another desired position around the banjo bolt
Solution Approach 1:
The banjo bolt is divided into two separate segments: a first segment with an outer conical threaded coupling part for screwing into the fuel pump, and a second segment with a male rotation part that receives the female rotation part of the banjo body. This segmentation allows the sealing function (first segment) to be separated from the rotatable connection function (second segment), enabling the banjo body to rotate freely without compromising sealing reliability.
2Reliability
If the banjo bolt is screwed into the screw hole far enough to compress the axial sealing rings, then fuel leakage is prevented, but the screw hole needs to be sufficiently deep which may not always be possible
Solution Approach 1:
The banjo bolt is segmented into two parts with different functions. The first segment contains the outer conical threaded coupling part that screws into the fuel pump housing, providing sealing through thread engagement without requiring deep screw holes. The second segment provides the male rotation part for the banjo body connection. This segmentation allows sealing to be achieved with minimal screw hole depth while maintaining structural integrity.
Solution Approach 2:
The patent employs a conical threaded coupling part instead of a conventional cylindrical thread. The conical geometry allows the threads to self-tighten and compress sealing elements as they are screwed in, achieving reliable sealing with shallower engagement depths compared to traditional parallel threads.
3Ease of manufacture
If a substantial play is left free between the split ring and the female rotation part to allow axial sliding, then assembly is simplified, but the banjo body becomes unstable and rattles
Solution Approach 1:
The patent removes the split ring component entirely and replaces it with a female rotation part that directly receives the male rotation part of the banjo bolt. This extraction of the intermediate split ring element eliminates the play and instability issues while simplifying the overall structure and improving connection stability.
4Reliability
If specific measures such as gluing, welding or soldering are taken to prevent the mounting part from unscrewing and improve sealing, then reliability is improved, but the banjo assembly cannot be removed or replaced
Solution Approach 1:
The patent creates a dynamic, reversible connection system where the first segment of the banjo bolt with the outer conical threaded coupling part can be screwed into and removed from the fuel pump housing multiple times. This replaces permanent fixation methods with a reusable threaded connection that maintains reliability through proper sealing design while enabling easy removal and replacement for maintenance or repositioning.
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 provides a stable, leak-free, and easily rotatable banjo assembly that can be connected to various elements without the need for deep screw holes, allowing for easy disassembly and reducing manufacturing complexity and costs.
Implementation Method 1
The second segment comprises an outer/external conical threaded second coupling part, also referred to as a male tapered threaded second coupling part, for making a screw coupling with a complementary threaded coupling opening provided inside another element
Implementation Method 2
utilizing axially slidable radial sealing rings for a play-free and robust fit
Data Source
Figure 1a~1d
Figure 2
Figure 3a~3b
AI summary
A banjo assembly comprises a banjo body (1) and a banjo bolt (2). A female rotation part (5) of the banjo body (1) fits rotatable around a male rotation part (15) of the banjo bolt (2), while the female rotation part (5) at one side is delimited by means of a head part (14). The banjo bolt (2) comprises a first and second segment (2') and (2"). The first segment (2') comprises said head part (14) and a first section (15a) of the male rotation part (15). The second segment (2") comprises a coupling part (20) and a second section (15b) of the male rotation part (15). The two sections (15a), (15b) are provided with complementary connection means (15b", 17) which are connected releasable with each other. The second coupling part (20) of the banjo bolt (2) comprises an outer conical thread.