Silicon Nitride Piston Ball Ends for Lighter Wear-Resistant Pumps
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Solution Overview
Problem
Traditional piston and shaft materials in pumps, such as tungsten carbide, are heavy and dense, posing a challenge in applications where weight is a consideration, and there is a need for a highly wear-resistant, lighter material.
Innovation Solution
The use of silicon nitride for the piston ball ends and optional tool steel driving members in piston pumps, which reduces density and weight while maintaining wear resistance, with a lower friction coefficient, enhancing lubricity and wear life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tungsten carbide is used for piston ball ends, then wear resistance is improved, but weight and density increase
Solution Approach 1:
The patent changes the material parameter from tungsten carbide to silicon nitride, fundamentally altering the density and weight characteristics while maintaining wear resistance. This material substitution directly resolves the contradiction by providing a lighter alternative that preserves the necessary durability for pump applications.
Solution Approach 2:
The patent employs silicon nitride as a ceramic material that combines lightweight properties with high wear resistance, effectively creating a composite solution that balances both requirements. The material selection represents a shift from traditional metal-ceramic composites to advanced ceramic materials that offer superior specific strength and lower density.
2Reliability
If tungsten carbide is used for piston ball ends, then wear resistance is improved, but density increases
Solution Approach 1:
The patent fundamentally changes the material composition parameter by substituting tungsten carbide with silicon nitride, resulting in a significant reduction in density while preserving wear resistance characteristics. This parameter change directly addresses the contradiction between durability and material density.
3Ease of manufacture
If tool steel is used for driving members, then manufacturing ease is improved, but friction coefficient increases
Solution Approach 1:
The patent changes the surface property parameter by specifying a rounded first portion on the ball end that contacts the driving member, modifying the geometric parameters to reduce friction. This geometric modification works in conjunction with the material selection to minimize friction while maintaining manufacturability.
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 silicon nitride piston ball ends provide improved wear resistance and lubricity, reducing overall pump weight and extending service life by minimizing friction and wear, thus increasing the operational hours of the pump.
Implementation Method 1
the friction coefficient between the ball end of the second shaft and the driving member of the pump can be about 0.11
Implementation Method 2
silicon nitride piston ball ends provide improved wear resistance and lubricity
Data Source
Figure 1~3
AI summary
In accordance with at least one aspect of this disclosure, a system includes, a cylinder barrel (108) configured to rotate within a pump housing (104) of a pump (102) operatively connected to a driving member (124) of the pump via a first shaft (106). A piston (110) is seated within a bore defined in the cylinder barrel. The piston is operatively connected to the driving member of the pump via a second shaft (126). The first shaft and the second shaft each include a ball end (128) configured to seat within the driving member. In embodiments, the ball end of at least the second shaft is of silicon nitride.