Milling Drum Axial Locking Using Drive-Applied Screw Torque

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Solution Overview

Problem

The existing axial position securing mechanism for soil cultivation machines, such as milling drums, is unreliable due to the use of threaded rods and locking nuts, which can lead to unpredictable loosening and tightening torques, and requires high-torque tools that are not always available on-site, posing safety and operational challenges.

Innovation Solution

A screw torque support arrangement that utilizes the machine's drive formation to apply high tightening and loosening torques to the central screw arrangement, eliminating the need for external tools and ensuring secure axial positioning with torques exceeding 2,500 Nm, and includes a screw torque support arrangement connected to the screw component, with a counter-support area on the machine body for stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a threaded rod and locking nut are used to secure the axial position, then the working device can be locked axially, but the loosening and tightening torques become unpredictable and unreliable

Engineering Contradiction:
Improveaxial position lock reliabilityVSAvoidtorque application predictability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of using a traditional locking nut that can loosen unpredictably, the patent inverts the approach by using a conical friction connection where the friction force itself provides the locking action. The conical surface geometry ensures that the friction force automatically adjusts to maintain a predictable and reliable axial position lock, eliminating the unpredictability of conventional nut-based systems.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical threaded rod and locking nut system with a friction-based conical connection system. This substitution eliminates the unpredictable torque characteristics of threaded fasteners and replaces them with a continuous frictional contact that provides stable and predictable axial positioning under varying load conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high tightening torque of more than 2,500 Nm is applied to ensure operational safety, then the axial position lock becomes secure, but special tools are required that are not available on-site

Engineering Contradiction:
Improveoperational safetyVSAvoidtool availability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The conical friction connection is designed to be self-securing through the inherent friction between the conical surfaces. The geometry of the cone angle and surface friction coefficient are selected to automatically generate sufficient locking force under operational loads, eliminating the need for external high-torque tools while maintaining operational safety and reliability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the fundamental parameters of the connection system by using a conical friction interface instead of a threaded connection. This parameter change allows the system to achieve high axial locking forces through friction rather than mechanical threading, thereby eliminating the need for special high-torque tools while maintaining secure axial positioning.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a threaded rod and locking nut system is used, then axial positioning can be achieved, but the system complexity increases with multiple components

Engineering Contradiction:
Improveaxial position securingVSAvoidscrew assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of the threaded rod, locking nut, and friction interface into a single integrated conical friction connection. This consolidation eliminates the need for multiple separate components while maintaining reliable axial position securing, thereby reducing device complexity without compromising functionality.

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

Enables safe and efficient establishment and release of the axial position lock, allowing for secure operation under high reaction forces without the need for cumbersome external tools, improving work safety and operational reliability.

Implementation Method 1

The screw torque support arrangement utilizes the machine's drive formation to apply high tightening and loosening torques to the central screw arrangement

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3896224A1Soil working machine
Publication Date: 2021.10.20 WIRTGEN GMBH
  • EP3896224A1 patent drawingFigure 1
  • EP3896224A1 patent drawingFigure 2
  • EP3896224A1 patent drawingFigure 3

AI summary

A soil cultivation machine (10), such as a road milling machine, a recycler, a stabilizer, a surface miner, and the like, comprises a machine body (13) with a machine frame (12) and a drive assembly (46; 146; 246) that can be driven to rotate relative to the machine frame about a drive axis (A) defining an axial direction, wherein the soil cultivation machine (10) comprises a working device (32; 132; 232) for soil cultivation, with which the drive assembly (46; 146; 246) is detachably connected to transmit a drive torque for common rotation, wherein the working device (32; 132; 232) extends axially between a drive axial end (32a) and a securing axial end (32b) opposite the drive axial end (32a), and the drive assembly (46; 146;246) of the soil cultivation machine (10) radially surrounds the outside, wherein, in the operational state of the soil cultivation machine (10), a cladding component (30a; 130a; 230a) is arranged opposite the securing axial end (32b) at a distance from the securing axial end (32) in the direction of the drive axial end (32a), which is pivotably connected to the machine frame (12) and which carries a floating bearing (76; 176; 276) supporting the working device (32; 132; 232) for rotation about the drive axis (A), which is connected to the cladding component (30a; 130a; 230a) for common pivoting movement.