Hydraulic Pump Expansion Chamber for Thermal Stress

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Solution Overview

Problem

Airtight hydraulic pump housings face increased stress and potential leakage or damage due to thermal expansion of hydraulic fluid, which existing designs fail to adequately accommodate.

Innovation Solution

Incorporating a smaller interior expansion chamber separated from the main chamber, which retains gas to accommodate volume changes of the hydraulic fluid, allowing the gas to expand or contract and mitigate pressure variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump housing is made airtight to prevent leakage, then sealing performance is improved, but thermal expansion of hydraulic fluid generates excessive pressure that may cause leakage or damage

Engineering Contradiction:

Improvesealing performanceVSAvoidpressure on housing

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The housing is divided into two separate chambers: a main interior chamber for hydraulic fluid and a smaller expansion chamber for gas. This segmentation allows the system to maintain airtight sealing in the main chamber while providing a dedicated space for thermal expansion accommodation, resolving the contradiction between sealing performance and pressure management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Gas in the expansion chamber acts as an intermediary substance that absorbs the volume changes of hydraulic fluid during thermal expansion. The gas expands and contracts to accommodate fluid volume changes, thereby mediating between the airtight main chamber and the thermal expansion forces, preventing excessive pressure buildup.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the housing is made airtight to contain hydraulic fluid, then fluid containment is improved, but thermal expansion causes increased stresses on the housing

Engineering Contradiction:

Improvefluid containmentVSAvoidhousing strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

By segmenting the housing into a main chamber for fluid containment and a separate expansion chamber for stress accommodation, the design maintains fluid containment integrity while providing a dedicated space to absorb thermal expansion stresses, thereby protecting the housing structure from excessive stress.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The expansion chamber is pre-configured to accommodate thermal expansion before it can cause damage to the housing. By providing advance cushioning space for volume changes, the system prevents stress buildup that would otherwise compromise housing strength.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If no expansion chamber is provided, then device complexity is reduced, but thermal expansion of fluid cannot be accommodated leading to pressure buildup

Engineering Contradiction:

Improvehousing structure complexityVSAvoidpressure from thermal expansion

Core Design Contradiction:

Device complexityVSStress or pressure

Solution Approach 1:

The expansion chamber is nested within the housing structure, utilizing available internal space. This nesting approach allows the system to accommodate thermal expansion without significantly increasing overall device complexity, as the expansion chamber integrates into the existing housing geometry rather than adding external components.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 solution effectively reduces stress on the pump housing, preventing leakage and damage by allowing the hydraulic fluid to expand and contract without causing excessive pressure, thereby ensuring the integrity of the hydraulic system.

Implementation Method 1

The fluid expands when heated and, where the pump housing is an airtight container, the fluid will generate pressure

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

retains gas therein when the main interior chamber is filled with a liquid, thereby accommodating changes of volume of the liquid

Methodology Applied

Scientific EffectGas compression: Compression

Data Source

PatentUS8062010B2Thermal expansion chambers for airtight containers

Publication Date: 2011.11.22 MARINE CANADA ACQUISTION INC

AI summary

A hydraulic pump has a rotor and a hollow housing with a main interior chamber. The rotor is rotatably mounted in the main interior chamber. A smaller interior chamber is separated from the main interior chamber such that the smaller interior chamber retains gas therein when the main interior chamber is filled with a liquid. There is also a method for accommodating changes in volume of hydraulic fluid within the main chamber of the hydraulic pump housing. The method comprises providing the smaller interior chamber separated from the main chamber and retaining gas within the smaller chamber when the main interior chamber is filled with liquid, whereby expansion or contraction of the gas accommodates changes of volume of the liquid within the housing.