Brake Pipe Union Screw Coating for Stable Tightening Torque
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Solution Overview
Problem
Existing union screws for brake pipes and fuel lines face issues with varying tightening torque due to different materials of the friction partners, leading to inconsistent tightening and potential loosening, and require complex layer removal for low friction, which complicates manufacturing.
Innovation Solution
A union screw with a multi-layered functional coating comprising a base coat of zinc-containing lamellae and a top coat of lubricant, where the lamellae are aligned flat to provide consistent friction and corrosion protection, reducing the pipe torque and ensuring a stable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional coating is applied to the union screw, then corrosion protection is provided, but the coefficient of friction varies greatly depending on the material of the friction partner, leading to inconsistent tightening torque
Solution Approach 1:
The patent applies a composite coating system consisting of a base coat layer (提供 corrosion protection) and a top coat layer (提供 friction control). This multi-layer composite structure allows each layer to perform its specific function independently, resolving the contradiction between corrosion protection and friction consistency.
Solution Approach 2:
The coating system applies different material properties to different regions/layers: the base coat provides corrosion resistance while the top coat provides consistent friction characteristics. This local differentiation of material properties allows simultaneous optimization of both corrosion protection and tightening torque consistency.
2Manufacturing precision
If the protective layer is completely removed from the pipe end section, then the flare surface is smooth and crack-free, but the friction between the pipe flare and union screw contact portion increases
Solution Approach 1:
The top coat layer on the union screw contact portion acts as an intermediary between the pipe flare and the screw contact surface. This intermediate layer reduces direct metal-to-metal friction while allowing the flare surface to maintain its high manufacturing quality with complete protective layer removal.
3Strength
If high friction is achieved in the threaded portion, then the union screw fits firmly in the threaded hole, but the friction coefficient varies with different threaded hole materials (aluminum or steel)
Solution Approach 1:
The top coat layer changes the surface friction parameters of the threaded portion to provide consistent friction characteristics regardless of the underlying material (aluminum or steel threaded hole). This parameter modification through coating ensures uniform tightening behavior across different material combinations.
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 achieves invariant tightening torque across different materials, minimizing torsional stress and ensuring a secure, corrosion-resistant connection with reduced pipe torque and improved longevity.
Implementation Method 1
a base coat which forms a structure comprising zinc-containing lamellae which are substantially aligned flat on the base body and a binder, wherein the top coat comprises a lubricant
Implementation Method 2
a top coat which is applied to the base coat at least partially and comprises a lubricant
Data Source
AI summary
A union screw (1) for pipes (2) provided with at least one flare (21) comprises a metal base body (10) which accommodates the pipe (20). The union screw (1) further comprises a screw head (12), a threaded portion (13), a contact portion (15) which is configured to abut the flare (21) of the pipe (20), and a functional layer (40) with which the base body (10) is coated at least in the region of the threaded portion (13) and the contact portion (15). The functional layer (40) is multi-layered and consists of at least one base coat (41) and a top coat (42) applied to the base coat (41) at least in some areas. The base coat (41) forms a structure for creating corrosion protection and a far-reaching invariance with regard to the material of the usual friction partners of the union screw (1) which, in addition to a binder, also contains zinc in the form of zinc-containing lamellae (43), which are oriented to lie substantially flat on the base body (10).