Pump Rotor Arcuate Flat Sections Pressure Release

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Solution Overview

Problem

Existing rotor apparatuses in pumps face challenges in efficiently releasing pressure from the air gap between the oil seal and the inner rotor without increasing the size of the inner rotor, which can lead to reduced durability and sealing performance.

Innovation Solution

The design features a drive shaft with arcuate and flat surface sections and an inner rotor with corresponding mounting hole sections, where the arcuate inner peripheral sections have larger radii and are offset, forming a pressure release channel with a large opening surface area to reduce pressure and maintain sealing ability without increasing the rotor's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the clearance between the drive shaft and inner rotor is increased to release pressure, then pressure release is improved, but the thickness of the inner rotor and tooth bottoms decreases, adversely affecting strength

Engineering Contradiction:

Improvepressure in air gapVSAvoidstrength of inner rotor

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The mounting hole of the inner rotor is divided into multiple arcuate circumferential surface sections and flat surface sections alternately arranged around the circumference. This segmentation allows creation of multiple pressure release channels distributed around the air gap, providing sufficient pressure release area without requiring excessive clearance in any single location, thus maintaining inner rotor strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies different surface characteristics (arcuate vs flat) at different circumferential locations of the mounting hole. The arcuate sections create larger clearance gaps for pressure release, while the flat sections maintain structural integrity. This local differentiation allows optimized pressure release without compromising overall strength.

Inventive Principle:

Principle #3Local quality

2Strength

If the diameter of the inner rotor is increased to ensure sufficient thickness, then strength is improved, but the size and weight of the oil pump increase

Engineering Contradiction:

Improvethickness of inner rotorVSAvoidweight of oil pump

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

By segmenting the mounting hole into alternating arcuate and flat surface sections, the invention creates multiple pressure release channels that provide sufficient pressure release capability without requiring a large overall clearance. This allows maintaining a compact inner rotor diameter while achieving effective pressure release, avoiding unnecessary increase in size and weight.

Inventive Principle:

Principle #1Segmentation

3Stress or pressure

If the clearance is increased to release pressure, then pressure release is improved, but the sealing ability and durability of the oil seal are degraded

Engineering Contradiction:

Improvepressure in air gapVSAvoidsealing ability of oil seal

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The segmented structure with multiple arcuate sections creates multiple distributed pressure release channels around the air gap. This provides sufficient total pressure release area to protect the oil seal without requiring any single clearance to be excessively large, thereby maintaining sealing ability while preventing oil seal degradation from pressure.

Inventive Principle:

Principle #1Segmentation

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 configuration effectively releases pressure, maintains good sealing and durability, and minimizes the radial thickness of the inner rotor, preventing pulsations and ensuring efficient operation while avoiding an increase in the rotor's size.

Implementation Method 1

the pressure of the fluid located in this air gap rises during operation... removing the fluid under a high pressure that is located inside the air gap from the air gap into the pump chamber

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

The lip sites of the oil seal are lubricated with the oil located inside the oil pump and the oil seal prevents the oil located in the oil pump from flowing out to the outside of the pump (oil leak)

Methodology Applied

Scientific EffectSealing:

Implementation Method 3

an axial hole which penetrates the inner rotor in the axial direction, and a clearance which is formed between the outer peripheral surface of the drive shaft and the inner peripheral surface of the axial hole of the inner rotor

Methodology Applied

Scientific EffectFluid flow through clearance:

Data Source

PatentUS7717689B2Rotor apparatus of pump including a drive shaft with a plurality of arcuate circumferential surface sections

Publication Date: 2010.05.18 HONDA MOTOR CO LTD

AI summary

To provide a rotor apparatus of a pump in which pressure release in the air gap between an oil seal and an inner rotor is conducted smoothly and good durability and sealing ability of the oil seal is maintained and which has a very simple structure and allows the increase in size to be avoided. The rotor apparatus of a pump includes a drive shaft in which a plurality of arcuate circumferential surface sections centering on an axial center and a plurality of flat surface sections are disposed alternately, and an inner rotor having a mounting hole into which the drive shaft is inserted. In the mounting hole, arcuate inner peripheral sections corresponding and equal in number to the arcuate circumferential surface sections and flat surface inner peripheral sections corresponding and equal in number to the flat surface sections are formed alternately.