Gear Pump End Plates With Spiral Grooves for Startup Wear Reduction
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Solution Overview
Problem
Gear pumps face wear-related issues due to inadequate lubrication at startup, leading to premature failure, especially at the gear and endplate bearing surfaces, and existing solutions like hydrodynamic slide bearings and gall-resistant materials struggle with efficiency and reliability under adverse conditions.
Innovation Solution
The introduction of spiral grooves on the end plates adjacent to the gear faces in gear pumps, oriented for inward pumping, creates a high pressure zone to separate the gear and plate surfaces, reducing wear and eliminating direct contact, thereby enhancing lubrication and thrust generation without compromising efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrodynamic slide bearings with variable depth are employed to reduce wear, then bearing surface protection is improved, but pump overall efficiency deteriorates
Solution Approach 1:
The patent applies spiral grooves only in specific regions where gears engage with end plates, rather than using full hydrodynamic bearings. This localized application provides wear protection exactly where needed (at gear-contact zones) while minimizing the overall impact on pump efficiency by limiting the modified area to only the critical bearing surfaces.
Solution Approach 2:
The spiral grooves utilize the pumped fluid itself to generate hydrodynamic pressure, creating a lubricating film between gear surfaces and end plates. This hydraulic mechanism reduces wear using the working fluid rather than requiring external lubrication systems or complex bearing structures that would reduce efficiency.
2Strength
If gall-resistant materials are used to withstand harsh contact, then wear resistance is improved, but premature failure still occurs under adverse pumping conditions
Solution Approach 1:
The spiral grooves create a fluid film that acts as an intermediary between the gear surfaces and end plates, preventing direct metal-to-metal contact. This fluid mediator protects the gall-resistant materials from harsh contact conditions, eliminating the root cause of premature failure rather than relying solely on material properties.
Solution Approach 2:
The spiral grooves establish a lubricating fluid film before significant wear or damage can occur. By preemptively creating this protective barrier through the groove geometry, the system prevents the adverse contact conditions that would otherwise lead to premature failure of even gall-resistant materials.
3Object-affected harmful factors
If surface treatments or coatings of wear resistant materials are applied to plate surface, then galling resistance is improved, but device complexity increases
Solution Approach 1:
The patent extracts the wear protection function from complex surface treatments and coatings, replacing them with a geometric feature (spiral grooves) that is simpler to manufacture and apply. The grooves create hydrodynamic pressure using only the pumped fluid, eliminating the need for additional materials or complex surface engineering processes.
4Reliability
If spiral grooves are provided in end plates for inward pumping, then wear reduction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The spiral grooves utilize curved, self-centering geometry that naturally guides the pumped fluid to generate hydrodynamic pressure. The curved spiral shape provides inherent alignment tolerances, as the rotational motion of the gears automatically centers the fluid flow within the grooves, reducing the need for extremely precise manufacturing compared to straight or angular groove configurations.
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 spiral groove design effectively reduces wear and improves the load-bearing capability of gear pumps, ensuring efficient operation and extending the lifespan of components by maintaining a consistent fluid film and balanced forces between the gears and end plates, eliminating the need for exotic materials or surface treatments.
Implementation Method 1
spiral grooves are provided in the end-plates adjacent to the faces of the pump gears... These grooves are oriented in an inward-pumping orientation in order to generate a high pressure zone between the opposing faces and ensure separation between the gear and plate
Data Source
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AI summary
A gear pump includes a housing, at least one gear set and a plurality of end plates. The gear set may be positioned between the end plates so that side surfaces of the gears face corresponding side surfaces of the end plates. The side surfaces of the end plates may have a plurality of spiral grooves positioned directly adjacent the side surface of the gears. The plurality of spiral grooves may have a logarithmic shape. Thus arranged, when the gears rotate, fluid in the pump is forced along the lengths of the spiral grooves, creating a local high pressure region that forces fluid between the side surfaces of the gears and the end plates, minimizing or eliminating contact therebetween. In some embodiments the plurality of spiral grooves may be positioned on bearing surfaces of the pump instead of end plates.