Gear Pump Journal Bearings with Heat Pipe Cooling

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Solution Overview

Problem

Gear pumps experience temperature increases due to friction, leading to reduced lifespan and increased risk of cavitation, particularly in high-pressure applications.

Innovation Solution

Incorporation of heat pipes as cooling circuits around journal bearings to transfer heat from the gear face to the remote face, utilizing a refrigerant that evaporates and condenses to maintain temperature balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If gears rotate to move fluid through friction, then fluid transport function is achieved, but temperature increases at journal bearings reducing lifespan and increasing cavitation risk

Engineering Contradiction:
Improvefluid transportVSAvoidpump lifespan
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Heat pipes are introduced as intermediary thermal management devices between the gear faces and the environment. These heat pipes conduct excess heat away from the journal bearings through their thermal conduction paths, preventing temperature buildup that would otherwise reduce pump lifespan and increase cavitation risk, while allowing continuous fluid transport operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces passive thermal management (relying on natural convection and conduction) with an active thermal control system using heat pipes. This substitution enables more effective heat removal from the journal bearings, maintaining lower operating temperatures and improving reliability without compromising the mechanical fluid transport function

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If cooling circuits are added to journal bearings, then temperature control is improved, but device complexity increases

Engineering Contradiction:
Improvejournal bearing temperatureVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat pipes are designed to be self-regulating thermal management devices that automatically respond to temperature differences without external control systems. The phase change mechanism within the heat pipes self-adjusts heat transfer rates based on thermal conditions, providing passive temperature control that minimizes system complexity while effectively managing journal bearing temperatures

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The heat pipes utilize phase transitions (evaporation and condensation) of a working fluid within the heat pipe structure to transfer heat from the gear faces to the external environment. This phase change mechanism provides high-efficiency heat transfer with minimal additional system complexity, as the phase transition process naturally occurs in response to temperature gradients without requiring external control

Inventive Principle:
Principle #36Phase transitions

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

Enhances the life expectancy of gear pumps by reducing temperature differences and minimizing cavitation risks.

Implementation Method 1

The refrigerant within the heat pipe is in liquid form adjacent the gear face of the journal bearing and evaporates to a vapor

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

The vapor is returned to liquid form adjacent the remote face of the journal bearing

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

Incorporation of heat pipes as cooling circuits around journal bearings to transfer heat from the gear face to the remote face

Methodology Applied
Scientific EffectHeat pipe: Heat Pipe

Data Source

PatentEP4170171B1Gear pump with cooled journal bearings
Publication Date: 2026.04.08 HAMILTON SUNDSTRAND CORP
  • EP4170171B1 patent drawingFigure 1
  • EP4170171B1 patent drawingFigure 2A~2B
  • EP4170171B1 patent drawingFigure 3~4C

AI summary

Fuel supply system and gear pump including gears (24,26) received within a housing (22) defining an inlet, an outlet and end plates (39). The gears have shaft portions on each of two sides of each of the two gears. The shaft portions are mounted in journal bearings (30,32,34,36) each having a gear side face adjacent one of the two gears. A remote face is on a remote side of the journal bearing remote from each of the two gears. There is a plurality of heat pipes in at least one of the journal bearings that move heat from the gear face of the at least one of the journal bearings to the remote face. The plurality of heat pipes is enclosed by the housing, and extend generally in an axial direction from an end adjacent the gear face to an end adjacent the remote face.