Electric Work Vehicle Motor Layout for Compact Wheel Drive

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Solution Overview

Problem

Existing electric work vehicles, such as electric tractors, lack an efficient and compact motor configuration that optimizes power distribution and wheel movement, leading to potential inefficiencies and limitations in performance and maneuverability.

Innovation Solution

A configuration with four motors, each driving a wheel, where the rear motors are housed in a rear housing with interlinked gearings, and a fifth motor drives a power take-off or hydraulic system, optimizing motor placement and gear casing width for enhanced power distribution and maneuverability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple motors are used to power wheels and components, then power distribution capability is improved, but device complexity increases

Engineering Contradiction:
Improvepower distribution capabilityVSAvoidmotor arrangement complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The vehicle is divided into multiple independent motor units, with each motor dedicated to driving a specific wheel or component. This segmentation allows each motor to be optimized for its specific function while maintaining overall system power distribution capability, resolving the contradiction between power capability and complexity through functional decomposition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rear housing serves multiple functions by housing both the third and fourth motors for wheel drive, as well as the fifth and sixth motors for component drive. This multi-functional design consolidates multiple motor units into a unified structure, reducing overall device complexity while maintaining the ability to power multiple wheels and components

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

2Productivity

If motors are spaced apart to drive individual wheels, then wheel drive efficiency is improved, but motor spacing requirements increase vehicle width

Engineering Contradiction:
Improvewheel drive efficiencyVSAvoidvehicle width
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

Instead of spacing motors apart only in the left-right direction, the design utilizes the front-rear dimension by positioning the third and fourth motors at different longitudinal positions within the rear housing. This dimensional redistribution allows each motor to drive its respective wheel effectively while minimizing the increase in vehicle width

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

3Area of stationary object

If gear casings are made thinner to reduce vehicle width, then vehicle compactness is improved, but gear casing structural integrity may be compromised

Engineering Contradiction:
Improvevehicle widthVSAvoidgear casing structural integrity
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The gear casing is designed with an asymmetric thickness distribution, being thinner at the outer edges where structural load is lower, and thicker in the central region where the gear train is located and structural integrity is most critical. This asymmetric design allows the gear casing to maintain adequate strength for gear support while minimizing overall width to improve vehicle compactness

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4549192B1Electric work vehicle
Publication Date: 2026.04.29 KUBOTA CORP
  • EP4549192B1 patent drawingFigure 1A
  • EP4549192B1 patent drawingFigure 1B
  • EP4549192B1 patent drawingFigure 1C

AI summary

An electric work vehicle (1) includes a frame, a rear housing, a first motor (14) to drive a first front wheel (2L), the first motor (14) being support by the frame, a second motor (16) to drive a second front wheel (2R), the second motor (16) being support by the frame, a third motor (18) to drive a first rear wheel (4L), the third motor (18) being support by the rear housing, and a fourth motor (20) to drive a second rear wheel (4R), the fourth motor (20) being support by the rear housing. The first motor (14) and the second motor (16) are spaced apart from each other by a first distance in a left-right direction of the electric work vehicle (1). The third motor (18) and the fourth motor (20) are spaced apart from each other by a second distance in the left-right direction of the electric work vehicle (1). The first distance is shorter than the second distance.