Segmented PTO Shaft with Dynamic Locking for Tractor Maintenance

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Solution Overview

Problem

The existing design of tractors with power take-off (PTO) transmissions impedes repair work due to the long shaft bridging the engine and PTO gearbox, making access and maintenance time-consuming and costly, and limits the accessibility of drive belts for power transmission.

Innovation Solution

A shaft system with a sleeve and homokinetic joints that allows axial movement and decoupling, enabling the creation of a gap for drive belt passage and facilitating the removal of shaft sections for easier access and maintenance, while ensuring smooth torque transmission and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If a long shaft is used to connect the engine and PTO gearbox, then torque transmission is achieved, but access to components behind the shaft is blocked making repairs time-consuming

Engineering Contradiction:
Improveaccess to componentsVSAvoidshaft structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The shaft is divided into multiple sections (first shaft section, second shaft section, third shaft section) that can be independently removed. The first shaft section can be detached from the second shaft section by moving the locking element, creating access space without removing the entire shaft assembly or PTO gearbox.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shaft incorporates a dynamic locking mechanism with a movable locking element that can switch between locked and unlocked positions. This allows the shaft structure to adapt between a fixed connected state for torque transmission and a flexible disassembled state for maintenance access.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If drive belts are mounted on shafts with large components at ends, then power transmission to consumers is achieved, but belt accessibility is limited

Engineering Contradiction:
Improvebelt accessibilityVSAvoidshaft configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

By segmenting the shaft into removable sections, the system allows drive belts to be mounted on intermediate shaft sections that remain accessible even when engine or PTO gearbox components are present at the ends. The removable first shaft section provides clearance for belt installation and replacement operations.

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If the shaft is made rigid for stable torque transmission, then power transmission reliability is improved, but maintenance access and component removal are hindered

Engineering Contradiction:
Improvecomponent removalVSAvoidtorque transmission
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The shaft employs a dynamic locking mechanism that provides rigid connection during normal operation for reliable torque transmission, and allows easy disconnection when the locking element is moved to the unlocked position, enabling component removal and maintenance access.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking element acts as an intermediary mechanism that mediates between the rigid shaft sections. When locked, it ensures firm connection for torque transmission; when unlocked, it allows the sections to be separated for maintenance, thus reconciling the contradiction between rigidity and accessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design reduces the complexity and cost of maintenance by allowing unhindered access to tractor components, improving the efficiency of repair work and enabling easier belt installation and replacement without compromising torque transmission.

Implementation Method 1

The sleeve can be a roller bearing, an outer ring of which touches an inner surface of the socket in the locked position, while an inner ring can be pushed onto the first shaft section. With the help of the roller bearing, the axes of the first and second shaft sections can be precisely aligned with one another without torque being transmitted between the shaft sections to any significant extent.

Methodology Applied
Scientific EffectRoller bearing: Roller

Data Source

PatentEP2628626B1Tractor with p.t.o. shaft drive
Publication Date: 2015.02.25 CLAAS TRACTOR
  • EP2628626B1 patent drawingFigure 1~2
  • EP2628626B1 patent drawingFigure 3~5
  • EP2628626B1 patent drawingFigure 5a

AI summary

The tractor has a motor (4), a power take-off (PTO) gear (6) and pulleys (24,25). The motor is connected with PTO gear by shaft (5). A main shaft portion (26) has a sleeve (16) which is radially and immovably engaged in a socket (32) of transmission side shaft portion (11), in locking position of shaft. An end portion (27) of main shaft portion is axially moved to pass through a lateral opening of socket of transmission side shaft portion, in unlocking position.