Gear Pump Suction Path for Filling Tooth Grooves at High Speed

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Solution Overview

Problem

The rotational speed of the drive and driven gears in conventional gear pumps makes it difficult for liquid to enter the tooth grooves, leading to reduced transfer efficiency.

Innovation Solution

A gear pump configuration with a suction-side communication path connecting a first space formed by meshing gears to the tooth grooves, ensuring liquid easily enters and fills the tooth grooves through suction-side communication paths, while preventing air ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotational speed of the gears is increased to improve productivity, then the liquid cannot easily enter the tooth grooves due to centrifugal force, but transfer efficiency deteriorates

Engineering Contradiction:
Improverotational speedVSAvoidtransfer efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The suction-side communication path is positioned to allow liquid to enter the tooth groove before the centrifugal force becomes dominant. The path connects the suction chamber to the tooth groove at a location where liquid can be drawn in advance, filling the groove before high-speed rotation prevents further entry. This preliminary filling action resolves the contradiction by ensuring the groove is filled before the harmful centrifugal effect takes over.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The suction-side communication path acts as an intermediary channel that facilitates liquid entry into the tooth groove despite the centrifugal force generated by high-speed rotation. This intermediate structure provides a direct flow path that overcomes the centrifugal barrier, allowing liquid to reach the groove bottom even at high rotational speeds, thus maintaining transfer efficiency while enabling high productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the tooth groove is not completely filled with liquid, then the pump efficiency is reduced, but air may enter the discharge passage

Engineering Contradiction:
Improvepump efficiencyVSAvoidair ingress
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The suction-side communication path enables preliminary filling of the tooth groove with liquid before the gear rotates to the discharge position. By positioning the path to connect the suction chamber directly to the groove, liquid is drawn in advance and fills the groove completely, preventing air from being trapped and subsequently entering the discharge passage. This preliminary action ensures both high pump efficiency and prevention of air ingress.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a communication path is provided to improve liquid entry, then transfer efficiency is enhanced, but the structure becomes more complex

Engineering Contradiction:
Improvetransfer efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The suction-side communication path serves multiple functions: it facilitates liquid entry into the tooth groove, maintains pressure balance, and prevents air ingress. By designing a single structural element that performs these multiple functions, the patent enhances transfer efficiency without proportionally increasing structural complexity. The path is integrated into the existing gear pump architecture, making it a multi-functional component rather than an additional separate system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 liquid transfer efficiency by ensuring easy filling of tooth grooves and minimizing air entry, thereby improving the overall operation of the gear pump.

Implementation Method 1

a suction-side communication path that connects a first space and a tooth groove of the gear, the first space being a closed space formed by the drive gear and the driven gear meshing with each other

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

The rotational speed of the drive gear 106 and the driven gear 108 may be, for example, about 50 or more revolutions per second. The centrifugal force generated by this rotation makes it difficult for the liquid to enter the tooth grooves 112 and 114 from the suction passage 110.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4098876B1Gear pump or gear motor
Publication Date: 2026.04.08 SHIMADZU CORP
  • EP4098876B1 patent drawingFigure 1
  • EP4098876B1 patent drawingFigure 2
  • EP4098876B1 patent drawingFigure 3

AI summary

To provide a gear pump or a gear motor in which a tooth groove is easily filled with a liquid. A gear pump (10) includes a casing (12), a gear storage chamber (14), a suction passage (16), a discharge passage (18), a gear that is housed in the gear storage chamber (14) and including a drive gear (20) and a driven gear (22) that rotate while meshing with each other, and a suction-side communication path (30) that connects a first space (46) and a tooth groove (48, 50) of the gear (20, 22), the first space (46) being a closed space formed by the drive gear (20) and the driven gear (22) meshing with each other, the tooth groove (48, 50) being opened to the suction passage (16).