Trochoid Oil Pump Linking Gap Design

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Solution Overview

Problem

Existing trochoid oil pumps face challenges in maintaining sufficient fluid linkage between contraction chambers, leading to increased pressure, cavitation noise, and reduced endurance due to limited gap sizes between tooth surfaces, which restrict fluid flow and cause inefficiencies.

Innovation Solution

A trochoid oil pump design featuring an inner and outer rotor with trochoid tooth profiles, where a linking gap between the tooth apex and base portions of the outer rotor expands gradually from the compression to discharge stroke, creating a continuous fluid path and preventing excessive pressure buildup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flat tooth surface is used to form a gap between teeth, then the structure is simple, but the gap size is limited and cannot maintain sufficient fluid linkage during contraction

Engineering Contradiction:

Improvetooth surface structureVSAvoidfluid linkage between chambers

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies curvature to the tooth surface by forming an arc-shaped recess instead of using a flat tooth surface. This curved geometry allows the gap between teeth to maintain adequate size and fluid linkage throughout the contraction stroke, resolving the limitation of flat surfaces while keeping the structure relatively simple.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent modifies only the specific region where fluid linkage is needed by forming an arc-shaped recess in the tooth surface. The rest of the tooth structure remains unchanged, allowing localized improvement of fluid flow characteristics without redesigning the entire gear system.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the gap between teeth is enlarged to maintain fluid linkage, then cavitation is reduced, but the drive contact portions cannot be avoided and structure becomes complex

Engineering Contradiction:

Improvecavitation noiseVSAvoidtooth surface structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The arc-shaped recess provides a curved geometry that naturally maintains adequate gap size for fluid linkage without requiring complex modifications to avoid drive contact portions. The curvature allows smooth fluid flow path while keeping the tooth structure simple and manufacturable.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The arc-shaped recess is pre-formed in the tooth surface to establish adequate fluid linkage from the beginning of the contraction stroke. This preliminary geometric configuration prevents cavitation before it occurs by ensuring continuous fluid communication between chambers throughout the contraction process.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If a limited-size gap is used between teeth, then the structure remains simple, but pressure buildup occurs and cavitation noise increases

Engineering Contradiction:

Improvetooth surface structureVSAvoidpressure inside contraction chamber

Core Design Contradiction:

Device complexityVSStress or pressure

Solution Approach 1:

The arc-shaped recess creates a progressively varying gap size that maintains adequate fluid linkage during contraction, allowing pressure to be gradually released to the discharge chamber. This curved geometry prevents excessive pressure buildup while keeping the structure simple and avoiding complex mechanisms.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design reduces pressure differences, inhibits cavitation, decreases pulsations and noise, and enhances the pump's endurance by ensuring adequate fluid flow and reducing drive power loss.

Implementation Method 1

a linking gap that links the interdental space and an interdental space that precedes the interdental space and is adjacent thereto is formed by a region without a contact with the tooth profile 5a of the inner rotor formed between the tooth apex portion and the tooth base portion of the tooth profiles of the outer rotor

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

the linking gap gradually expands with the rotation of the rotor... preventing an excess increase in pressure of the fluid inside the interdental space of the contraction stroke

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

preventing the occurrence of noise and erosion caused by cavitation

Methodology Applied

Scientific EffectCavitation: Cavitation

Data Source

PatentUS7488163B2Trochoid oil pump

Publication Date: 2009.02.10 YAMADA MANUFACTURING CO LTD

AI summary

A trochoid oil pump, which enables the endurance to be increased and the reduction of discharge pulsations and noise to be achieved, and in which those results can be realized with a very simple structure.An interdental space constituted by an inner rotor and an outer rotor having trochoid tooth profile or substantially trochoid tooth profile starts a compression stroke in the location of a partition section between an intake port and a discharge portion, and a linking gap L is composed by the interdental space and a preceding adjacent interdental space realized in a discharge stroke. The linking gap expands gradually from the start of compression stroke to the discharge stroke.