Milling Drum Central Bolt Retention Using Drive-Applied High Torque
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Solution Overview
Problem
Existing earth working machines, such as road milling machines, face challenges in reliably retaining and releasing the milling drum due to the axial positional retention system's unpredictability and the need for high torque, which is cumbersome to apply with conventional tools.
Innovation Solution
The system employs a bolting moment bracing arrangement that uses the drive configuration to apply high tightening and loosening torques to the central bolt arrangement, eliminating the need for external tools and allowing for axial positional retention with bolting moments exceeding 2500 Nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded rod and retaining nut arrangement is used for axial positional retention, then the working apparatus can be retained on the drive configuration, but the retention system becomes complex and the release point becomes unpredictable
Solution Approach 1:
The bolt arrangement is segmented into a threaded rod component and a retaining nut component that can move independently relative to each other. This segmentation allows the threaded rod to be screwed into the drive configuration while the retaining nut can move along the threaded rod, simplifying the overall structure while maintaining retention reliability.
Solution Approach 2:
The retaining nut acts as an intermediary element between the threaded rod and the working apparatus. It transfers the axial retention force from the threaded rod to the working apparatus while allowing controlled movement during the release process, making the release point predictable.
2Reliability
If conventional tools are used to apply tightening torque, then the bolt arrangement can be secured, but high torque requirements make the operation cumbersome and difficult
Solution Approach 1:
A bracing arrangement serves as an intermediary mechanism that converts the rotational movement of the drive configuration into axial tightening force on the bolt arrangement. This eliminates the need for external torque tools while achieving the required high tightening torque through the machine's own drive system.
Solution Approach 2:
The drive configuration itself is used to apply the tightening torque to the bolt arrangement, making the system self-servicing. The working apparatus is tightened using the rotational force already available in the drive system, eliminating dependency on external tools and operators.
3Reliability
If the retaining nut is allowed to move relative to the threaded rod during release, then the release process becomes unpredictable, but constraining it makes the system more complex
Solution Approach 1:
The system transitions from a static constraint to a dynamic controlled movement. The retaining nut is designed to move along the threaded rod in a controlled manner during release, with the movement governed by the threading geometry and the rotational direction of the drive configuration, making the release point predictable without additional constraints.
Data Source
AI summary
An earth working machine includes a machine frame, a drive configuration and a milling drum. A bearing stem is attached to one of the drive configuration and the milling drum, the bearing stem protruding in a first direction to a first axial end, the bearing stem having an outer surface including at least first and second cylindrical bearing surfaces axially spaced from each other, a furthest one of the cylindrical bearing surfaces from the drive axial end having a smaller diameter than a next furthest one of the cylindrical bearing surfaces from the drive axial end. A non-locating bearing is connected to the machine frame and configured to receive the first and second cylindrical bearing surfaces of the bearing stem.