External Gear Machine Microsurfaces for Axial Balance and Lubrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional external gear machines (EGMs) face challenges in achieving optimal balancing of lateral bushings due to simplified design approaches, leading to increased wear and leakage under high-pressure conditions, as they do not accurately account for elastohydrodynamic effects and micromotion.
Innovation Solution
The design incorporates gear teeth with shaped lateral surfaces forming a wedge or step configuration, and lateral bushings with periodic features, optimizing the lubricating gap and balancing areas to enhance hydrodynamic effects and axial balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simplified numerical approaches or empirical procedures are used to design balancing areas, then device complexity is reduced, but manufacturing precision and reliability deteriorate due to increased wear and leakage
Solution Approach 1:
The patent applies parameter changes by introducing elastohydrodynamic theory and micromotion analysis to transform the design approach from simplified empirical methods to a more rigorous mathematical model. This involves changing the design parameters to include film thickness, pressure distribution, and micromotion characteristics that were previously neglected, thereby improving balancing area accuracy without excessively increasing design complexity
Solution Approach 2:
The patent replaces the simplified mechanical design approach with a more sophisticated elastohydrodynamic analysis system. This substitution introduces fluid film mechanics and elastic deformation considerations into the balancing area design, replacing the purely mechanical empirical methods with a coupled fluid-structure interaction model that accurately predicts wear and leakage behavior
2Ease of manufacture
If conventional balancing areas are used, then ease of manufacture is improved, but reliability deteriorates under high-pressure conditions due to increased wear
Solution Approach 1:
The patent applies local quality by identifying specific regions within the balancing area that require enhanced precision and material properties. By analyzing the pressure distribution and micromotion patterns, the invention determines local zones where wear is most critical and applies targeted design modifications to those specific areas rather than uniformly increasing complexity across the entire component
Solution Approach 2:
The patent implements preliminary action by incorporating elastohydrodynamic considerations and micromotion analysis into the early design stage of balancing areas. This allows potential wear and leakage problems to be predicted and addressed before manufacturing, enabling the use of conventional manufacturing processes to produce components with optimized geometry that inherently resist wear under high-pressure conditions
3Device complexity
If lateral lubricating interface design does not achieve optimal gap conditions, then device complexity remains low, but reliability deteriorates due to increased frictional loss and wear
Solution Approach 1:
The patent applies feedback by using elastohydrodynamic analysis to predict the lubricating film characteristics and micromotion behavior, then using this information to refine the balancing area design. This iterative process incorporates feedback from theoretical calculations about film thickness and pressure distribution to optimize the gap conditions, ensuring reliable operation without excessively complicating the interface design
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
This approach reduces power losses, wear on components, and improves the operating conditions range by creating thicker lubricating films and minimizing leakage, resulting in enhanced mechanical efficiency and extended machine life.
Implementation Method 1
The gears and lateral bushings, the major solid components that form the lateral lubricating gaps, conventionally have flat, smooth surfaces (barring wear patterns). The flat surfaces of the gears and lateral bushings do not provide any additional aid in achieving optimal gap conditions through contributing additional hydrodynamic effects.
Implementation Method 2
The balancing areas are positioned on the side of each lateral bushing plate (e.g., on lateral bushing plates 120 facing away from the gears 110, 112 in FIG. 2A) and are intended to contribute to the force balance, also known as the 'axial balance,' of the floating lateral bushings. In operation, the balancing areas are supposed to generate pressure forces that, in theory, balance the pressure forces and moments arising from the lateral lubricating interface and the tooth space volumes.
Data Source
AI summary
Devices and systems relating to external gear machines that comprise microsurface shaping on the lateral surfaces of the gear teeth and/or bushing surfaces are provided. Such microsurface shaping may comprise a flat step to linear wedge profile, a flat step to flat step profile, or solely a linear wedge profile. The incorporation of microsurface shaping on the gear teeth and/or bushing plates contributes to improving the lubrication performance within the external gear machine and provides significant benefits, including the improvement of operating efficiency, life, and reliability of the system components. Methods for manufacturing the gear teeth and related bushings are also provided, the methods configured to optimize the overall axial balance within the system.