Fiber-Reinforced Pump Sealing Ring With Machined Inner Surface
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Solution Overview
Problem
Piston pumps for internal combustion engines face issues with large dimensional tolerances and varying tribological properties due to the presence of an injection skin on plastic seals, which affect their performance and functionality.
Innovation Solution
A piston pump with a sealing ring made of fiber-reinforced plastic, where the inner circumferential surface is machined to remove the injection skin, exposing reinforcing fibers, thereby reducing tolerances and improving tribological properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic seal is manufactured using injection molding, then the manufacturing process is simple and cost-effective, but the dimensional tolerances are large and tribological properties vary
Solution Approach 1:
The sealing ring is divided into two distinct parts: an injection-molded base section made from fiber-reinforced plastic, and a separately machined inner circumferential surface. This segmentation allows each part to be optimized independently - the base section benefits from efficient injection molding while the inner surface achieves precise dimensional tolerances through subsequent machining operations.
Solution Approach 2:
The injection molding process is performed first to create the base section with approximate dimensions, and then machining is applied to the inner circumferential surface to achieve final precise dimensions. This preliminary action approach allows the bulk material to be formed efficiently before applying precision finishing only where needed.
2Productivity
If a plastic seal is manufactured using injection molding, then production is efficient, but the tribological properties of the component surfaces vary
Solution Approach 1:
Different surface qualities are applied to different regions of the sealing ring. The outer surface maintains the injection-molded finish for production efficiency, while the inner circumferential surface receives specialized machining treatment to achieve consistent, optimized tribological properties. This local quality differentiation ensures each surface has the appropriate characteristics for its functional requirements.
Solution Approach 2:
The sealing ring uses fiber-reinforced plastic as the base material, combining plastic matrix with reinforcing fibers. This composite material structure provides both the production efficiency of injection molding and improved dimensional stability and tribological consistency compared to plain plastic, as the fibers reduce material variability.
3Device complexity
If the injection skin is left on the component surface, then no additional processing is needed, but dimensional tolerances and functional performance deteriorate
Solution Approach 1:
The injection skin is selectively removed from the inner circumferential surface through machining operations. This extraction eliminates the problematic outer layer while preserving the beneficial fiber-reinforced structure beneath, achieving improved dimensional tolerances and surface quality without requiring complete remanufacturing of the component.
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 machining process enhances the sealing ring's functionality by reducing friction and improving dimensional accuracy, leading to better performance and reliability under operating conditions.
Implementation Method 1
The sealing ring is formed from fiber-reinforced plastic by injection molding and is machined on the inner circumferential surface. The injection skin is largely or completely removed by machining the inner circumferential surface.
Implementation Method 2
the fibers, i.e., the reinforcing fibers contained in the sealing ring material, can be carbon fibers. Due to their good lubricating properties, the carbon fibers can contribute to reducing friction on the inner circumferential surface.
Data Source
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AI summary
A piston pump (16), in particular a high-pressure fuel pump for an internal combustion engine, comprising: a pump housing (26); a pump piston (28) which is guided in the pump housing (26); a conveying chamber (38) which is delimited at least by the pump housing (26) and the pump piston (28); and a seal (43) which is arranged between the pump housing (26) and the pump piston (28) and which serves for sealing the conveying chamber (38). The seal (43) is configured as a sealing ring (44), with a substantially sleeve-shaped base section (45) extending along a centre longitudinal axis (41), and comprises an inner circumferential surface (57), wherein the sealing ring (44) is configured from fibre-reinforced plastic by means of injection moulding, and is machined on the inner circumferential surface (57).