Hydraulic Hose Layout to Prevent Pump Idling in Work Vehicles

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Solution Overview

Problem

Hydraulic pumps placed higher than the liquid level in a hydraulic oil tank can experience idling issues, leading to damage or failure when the engine stops, restricting their positioning and layout in work vehicles.

Innovation Solution

The hydraulic pump is positioned higher than the liquid level with at least part of the hydraulic hose placed lower than the liquid level, preventing hydraulic oil from flowing back and reducing idling-induced damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the hydraulic pump is placed in a position higher than the liquid level of the hydraulic oil in the hydraulic oil tank, then the freedom degree in the setting of the hydraulic pump is increased, but the hydraulic pump may idle and drain when the engine is stopped, causing damage or failure

Engineering Contradiction:
Improvefreedom degree in the setting of the hydraulic pumpVSAvoidhydraulic pump damage or failure
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dimensional change by routing the second hydraulic hose below the liquid level (vertical dimension) while keeping the hydraulic pump positioned above the liquid level. This spatial reconfiguration allows the pump to be placed in a higher position for better adaptability while the hose dip tube extends downward to prevent oil drainage, resolving the contradiction between pump positioning freedom and pump reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the hydraulic pump is placed in a position lower than the liquid level of the hydraulic oil in the hydraulic oil tank, then the hydraulic pump can prevent idling and damage, but the freedom degree in the setting of the hydraulic pump is restricted

Engineering Contradiction:
Improvehydraulic pump damage or failureVSAvoidfreedom degree in the setting of the hydraulic pump
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by using vertical dimensional separation: the hydraulic pump is positioned in the upper region for design flexibility, while the second hydraulic hose extends downward below the liquid level to ensure oil supply. This multi-level spatial arrangement allows both the pump placement freedom and the prevention of pump idling to be achieved simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the hydraulic hose is arranged to allow the hydraulic pump to be positioned higher, then the pump placement flexibility is improved, but the hydraulic oil may flow back to the tank via the hydraulic hose, emptying the pump

Engineering Contradiction:
Improvepump placement flexibilityVSAvoidhydraulic oil flow back to tank
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by extending the second hydraulic hose below the liquid level before the engine stops and oil drainage occurs. This pre-positioned hose configuration ensures that when the engine stops and gravity causes oil to flow back, the hose already extends into the oil reservoir, maintaining a seal and preventing oil loss from the pump system while allowing the pump to be positioned higher.

Inventive Principle:
Principle #10Preliminary action

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 reduces hydraulic pump damage, increases layout freedom, and allows for a more compact and efficient design of the work vehicle.

Implementation Method 1

the hydraulic pump is placed in a position higher than a liquid level of the hydraulic oil in the hydraulic oil tank, and at least part of the second hydraulic hose is placed in a position lower than the liquid level

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4219841B1Work vehicle
Publication Date: 2026.04.29 YANMAR HLDG CO LTD
  • EP4219841B1 patent drawingFigure 1
  • EP4219841B1 patent drawingFigure 2
  • EP4219841B1 patent drawingFigure 3

AI summary

[Problem] To provide a work vehicle in which a hydraulic pump's damage or failure due to the idling of the hydraulic pump can be reduced even in a configuration where a hydraulic pump is placed in a position higher than a liquid level of a hydraulic oil in a hydraulic oil tank, thereby making it possible to increase the freedom degree in the setting of the hydraulic pump. [Solution] A work vehicle includes: a hydraulic oil tank that tanks a hydraulic oil, a hydraulic pump connected via a first hydraulic hose to the hydraulic oil tank, and a hydraulic equipment connected via a second hydraulic hose to the hydraulic pump. The hydraulic pump is placed in a position higher than a liquid level of the hydraulic oil in the hydraulic oil tank. At least part of the second hydraulic hose is placed in a position lower than the liquid level.