Gear Pump Bearing Clearance Features for Leakage Reduction

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Solution Overview

Problem

Conventional gear pumps face high manufacturing costs due to the expensive process of lapping bearings to achieve tight clearances, which results in reduced volumetric efficiencies and larger internal leakages when cost-reducing measures like controlled center distances and larger clearances are used.

Innovation Solution

A gear pump bearing design featuring a body with clearance-consuming features such as pins or raised outer diameter extensions that occupy a portion of the pump housing cavity, reducing motion and achieving tight clearances without increasing the bearing's outer diameter, thereby minimizing manufacturing costs and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If lapping bearings to fit housing is used, then tight clearances are achieved, but manufacturing cost increases

Engineering Contradiction:
Improveclearance toleranceVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The bearing body incorporates clearance-consuming features (protrusions, pins, or extensions) that are pre-formed during bearing manufacturing. These features are designed to occupy specific clearance spaces within the housing cavity before the bearing is installed, eliminating the need for post-manufacturing lapping operations to achieve tight clearances.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of uniformly reducing clearance across the entire bearing surface through expensive lapping, the invention applies clearance-consuming features at specific localized positions on the bearing body. These features strategically occupy clearance spaces where they most effectively reduce internal leakage paths without requiring complete surface precision.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If controlled center distances and larger clearances are used, then manufacturing cost decreases, but volumetric efficiency reduces

Engineering Contradiction:
Improvemanufacturing costVSAvoidvolumetric efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention accepts that larger clearances would normally increase internal leakage and reduce volumetric efficiency. However, it converts this potential harm into a benefit by strategically placing clearance-consuming features within the larger clearance space. These features occupy the leakage paths, transforming the otherwise harmful large clearance into an effective sealing solution that maintains volumetric efficiency without requiring expensive tight clearance manufacturing.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If bearing size is increased to occupy more cavity, then clearance is reduced, but bearing outer diameter increases

Engineering Contradiction:
Improveclearance reductionVSAvoidbearing outer diameter
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

Instead of increasing the overall bearing outer diameter to occupy more housing cavity space, the invention segments the clearance occupation function into separate features attached to or integrated with the bearing body. These clearance-consuming features (pins, protrusions, extensions) are distributed around the bearing periphery, collectively occupying clearance spaces without requiring an increase in the main bearing diameter.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3597919B1Gear pump bearings
Publication Date: 2022.11.02 HAMILTON SUNDSTRAND CORP
  • EP3597919B1 patent drawingFigure 1
  • EP3597919B1 patent drawingFigure 2
  • EP3597919B1 patent drawingFigure 3

AI summary

A gear pump bearing can include a body (101a-101d) sized and shaped to occupy a portion of a pump housing cavity (103) such that a clearance is formed between the body (101a-101d) and a pump housing (105). The gear pump bearing can also include at least one clearance consuming feature (107) extending from an outer surface of the body (101a-101d) configured to reduce motion of the body within the pump housing cavity (103).