Rear Crawler Swing Shaft Positioning for Traction and Turning

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Solution Overview

Problem

Existing work vehicles face challenges in traction, turn ability, and performance when running through paddy fields due to the positioning of the swing shaft in the front-back direction of the body.

Innovation Solution

A work vehicle with a position change mechanism that moves a swing shaft in the front-back direction of the body, allowing it to be positioned optimally for traction, turning, or running through paddy fields, using an actuator such as a hydraulic cylinder to facilitate this movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the swing shaft is positioned at a fixed location, then the structure is simple, but the traction and turn ability are insufficient

Engineering Contradiction:
Improvetraction and turn abilityVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The swing shaft is made movable along the rear axle in the longitudinal direction through a position change mechanism driven by a hydraulic actuator. This dynamic positioning capability allows the swing shaft to be adjusted between a first position for improved traction and a second position for reduced turn radius, resolving the contradiction between adaptability and structural simplicity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The longitudinal position of the swing shaft is changed by varying the extension length of the actuator. By adjusting this parameter, the system can optimize performance for different operating conditions - achieving better traction when the swing shaft is at the first position and smaller turn radius when at the second position

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the swing shaft is positioned forward, then the turn radius is reduced, but the traction is compromised

Engineering Contradiction:
Improveturn abilityVSAvoidtraction force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The system dynamically adjusts the swing shaft position based on operational requirements. When turning is needed, the actuator moves the swing shaft to the second (forward) position to reduce turn radius. When traction is needed, the swing shaft is positioned at the first (rearward) position to maximize ground contact and friction force

Inventive Principle:
Principle #15Dynamics

3Force

If the swing shaft is positioned backward, then the traction is improved, but the turn radius increases

Engineering Contradiction:
Improvetraction forceVSAvoidturn ability
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The position change mechanism allows the swing shaft to be moved backward to the first position when maximum traction is required, such as when climbing slopes or moving heavy loads. When maneuvering in tight spaces is needed, the actuator repositions the swing shaft forward to the second position to achieve a smaller turn radius

Inventive Principle:
Principle #15Dynamics

4Power

If the front wheels apply high ground contact pressure, then the drive force is increased, but the paddy field is damaged

Engineering Contradiction:
Improvedrive forceVSAvoidfield damage
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

Instead of increasing drive force solely through wheel power, the invention utilizes the longitudinal movement of the swing shaft as an additional degree of freedom. By adjusting the swing shaft position, the system optimizes the leverage and mechanical advantage of the drive system, achieving sufficient drive force without necessarily increasing front wheel ground contact pressure that would damage the paddy field

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

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

Improves traction by ensuring rear crawler units maintain ground contact and reduces the minimum turn radius, enhancing turnability while minimizing damage to paddy fields.

Implementation Method 1

the actuator includes a hydraulic cylinder configured to extend and contract in the front-back direction of the body

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4053001B1Work vehicle
Publication Date: 2025.08.20 KUBOTA CORP
  • EP4053001B1 patent drawingFigure 1
  • EP4053001B1 patent drawingFigure 2
  • EP4053001B1 patent drawingFigure 3

AI summary

A work vehicle includes: a body; left and right front wheels provided for the body; and left and right rear crawler units (8) provided for the body. The rear crawler units (8) each include: a drive wheel (16) provided for a rear axle (15) of the work vehicle; a front idler wheel (17) forward of the drive wheel (16); a rear idler wheel (18) backward of the drive wheel (16); a plurality of roller wheels (19) between the front idler wheel (17) and the rear idler wheel (18); a crawler belt (20) wound around the drive wheel (16), the front idler wheel (17), the rear idler wheel (18), and the plurality of roller wheels (19); a track frame (21) swingable about a swing shaft (26) that extends in a left-right direction of the body and holding the front idler wheel (17), the rear idler wheel (18), and the plurality of roller wheels (19); and a position change mechanism (22) configured to move the swing shaft (26) in a front-back direction of the body.