Electric Work Vehicle Motor-Pump Layout for Low-Loss Hydraulics

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Solution Overview

Problem

The existing work vehicles with engine replacements by batteries and motors face challenges of large machine body size and significant power loss during transmission to hydraulic pumps due to the need for a transmission mechanism.

Innovation Solution

An electric work vehicle design featuring a compact transmission mechanism with the motor and hydraulic pump closely located, using an integral transmission input and output shaft configuration, and an endless rotary body for power transfer, which reduces the machine body size and power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a transmission mechanism is included to transmit driving force from the motor to the hydraulic pump, then the work vehicle can operate the hydraulic work device, but the machine body becomes large-sized

Engineering Contradiction:
Improvehydraulic work device operationVSAvoidmachine body size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The motor and hydraulic pump are integrated into a single compact transmission mechanism where the motor shaft is directly coupled to the pump shaft through a coupling section. This merging of components eliminates the need for separate transmission systems and reduces the overall machine body size while maintaining full hydraulic functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a transmission mechanism is included to transmit driving force from the motor to the hydraulic pump, then the work vehicle can operate the hydraulic work device, but power loss increases during transmission

Engineering Contradiction:
Improvehydraulic work device operationVSAvoidpower loss during transmission
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The invention extracts and eliminates unnecessary intermediate transmission components by directly coupling the motor shaft to the pump shaft. This direct connection removes redundant mechanical elements that would cause power loss, achieving efficient power transmission while maintaining hydraulic work device operability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the motor and hydraulic pump are positioned far apart, then the layout is flexible, but the transmission mechanism becomes large and causes power loss

Engineering Contradiction:
Improvelayout flexibilityVSAvoidpower loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The motor and hydraulic pump are merged into a closely integrated assembly where the motor shaft and pump shaft are directly connected through a coupling section. This merging eliminates the need for long-distance power transmission and complex layout arrangements, reducing both machine body size and power loss while maintaining adequate layout flexibility.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for a smaller machine body and minimal power loss during transmission, enabling efficient operation of electric work vehicles without the drawbacks of larger size and power loss.

Implementation Method 1

an endless rotary body windable around the first rotor and the second rotor

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3987902B1Electric work vehicle
Publication Date: 2024.12.11 KUBOTA CORP
  • EP3987902B1 patent drawingFigure 1
  • EP3987902B1 patent drawingFigure 2
  • EP3987902B1 patent drawingFigure 3

AI summary

An electric work vehicle includes: a work device; a battery; a motor M drivable on electric power supplied by the battery; a travel device drivable by the motor M; and a hydraulic pump 60 positioned next to the motor M and drivable by the motor M and configured to supply operating oil to an operating mechanism of the work device. (Fig. 6)