Undercutting Cutter Assembly Rolling Element Load Segmentation
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Solution Overview
Problem
The life span of bearing arrangements in undercutting machines for rock workfaces is limited due to high forces encountered during operation, and existing solutions fail to efficiently manage these forces, leading to premature wear and maintenance challenges.
Innovation Solution
A cutter assembly with a shaft supporting structure, a shaft, and two rolling elements – one designed for radial loads and the other for axial loads, allowing for clear load case definition and efficient bearing design, along with a third rolling element for pretension and load transfer, enabling extended bearing life and reduced maintenance complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bearing arrangement is used to accommodate high forces during rock cutting, then the cutter assembly can perform cutting operations, but the life span of the bearing arrangement is limited due to premature wear
Solution Approach 1:
The bearing arrangement is segmented into multiple rolling elements (first rolling element, second rolling element, and optionally third rolling element) that are distributed along the shaft. Each rolling element is positioned to handle specific load components, dividing the high forces into manageable segments that reduce wear on individual elements and extend overall bearing life span.
Solution Approach 2:
Each rolling element is given specific local qualities and positioning: the first rolling element handles radial loads, the second rolling element (with its specific orientation where a line orthogonal to its outer surface crosses the shaft axis within +/- 25% of the first rolling element's axial extension) handles axial loads, and the third rolling element provides pretension. This localized optimization of each element's function reduces premature wear.
2Reliability
If multiple rolling elements are arranged to handle different load cases, then the bearing life span is extended, but the device complexity increases
Solution Approach 1:
The rolling elements serve multiple functions: they support radial loads, axial loads, and provide pretension while also enabling non-destructive disassembly. The shaft supporting structure integrates multiple bearing functions into a unified design that, while complex in arrangement, provides versatile load handling capabilities that extend bearing life span.
Solution Approach 2:
The third rolling element is arranged to provide preliminary pretension to the bearing arrangement before operation begins. This pretension pre-loads the rolling elements optimally, ensuring they are ready to handle high forces from the start of cutting operations, which extends bearing life span while the modular design keeps complexity manageable.
3Ease of repair
If the cutter device is made detachable for easy maintenance, then the ease of repair is improved, but the structural complexity of the shaft supporting structure increases
Solution Approach 1:
The cutter assembly is segmented into detachable components: the cutter device can be separated from the shaft, and the shaft can be separated from the shaft supporting structure. This segmentation allows the cutter device to be easily replaced for maintenance while the shaft supporting structure retains the necessary complexity to accommodate the bearing arrangement and enable non-destructive disassembly through the specifically positioned rolling elements.
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
The solution enhances the life span of the bearing assembly by clearly defining load cases for each rolling element, reducing radial loads on the axial bearing and allowing for efficient design, resulting in extended bearing life at lower costs and reduced installation space, while enabling non-destructive disassembly and maintenance of the cutter assembly.
Implementation Method 1
a first rolling element arranged between the shaft supporting structure and the shaft in floating or slidable manner in axial direction; a second rolling element arranged between the shaft supporting structure and the shaft
Data Source
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AI summary
The invention relates to a cutter assembly (1) for an undercutting machine for cutting a rock workface and a method of disassembling a cutter assembly. The cutter assembly comprises a shaft supporting structure (10); a shaft (100) at least partly arranged within the shaft supporting structure; a cutter device (200) arranged on the shaft or the shaft supporting structure; a first rolling element (510) arranged between the shaft supporting structure and the shaft in floating or slidable manner in axial direction; a second rolling element (520) arranged between the shaft supporting structure and the shaft, wherein a line orthogonal to an outer surface of the second rolling element crosses the longitudinal axis (X) of the shaft at a centre plane of the first rolling element or within a range of +/- 25% of an axial extension of the first rolling element from said centre plane.