Rotatable Two-Piece Shank Bushing for Even Wear Distribution
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Solution Overview
Problem
Existing rock drilling machines face issues with wear of the shank bushing due to uneven distribution of wear on surfaces, leading to reduced operating life and increased maintenance needs.
Innovation Solution
A two-piece shank bushing assembly is surrounded by a bearing bushing, allowing for rotation and even distribution of wear, supported by a separate wearing bushing that can be easily replaced, and featuring a split configuration for mounting and dismounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a traditional single-piece shank bushing is used, then the structure is simple and easy to manufacture, but wear is concentrated on specific surfaces leading to reduced operating life
Solution Approach 1:
The shank bushing is divided into two separate half-bushings that can be assembled around the shank adapter. This segmentation allows the bushing to be rotated, distributing wear evenly across all surfaces rather than concentrating it on specific areas, thereby extending the operating life of the stationary object.
2Duration of action of stationary object
If a two-piece shank bushing is used, then wear is distributed evenly extending operating life, but the structure becomes more complex
Solution Approach 1:
By segmenting the bushing into two halves, the manufacturing complexity is managed through standardized half-bushing components that can be produced using conventional machining processes. The segmentation enables even wear distribution across all surfaces when the bushing rotates, significantly extending operating life despite the additional manufacturing steps required.
3Duration of action of stationary object
If a two-piece shank bushing is used, then wear distribution is improved, but mounting and dismounting becomes more complex
Solution Approach 1:
The two-piece configuration with split configuration allows the half-bushings to be easily assembled around the shank adapter from opposite sides. This segmentation simplifies mounting and dismounting operations compared to a single-piece design that would require complete disassembly, while simultaneously enabling even wear distribution that extends operating life.
4Duration of action of stationary object
If the shank bushing is made rotatable, then wear is distributed evenly, but additional support structure is required
Solution Approach 1:
A bearing bushing is introduced as an intermediary component between the shank bushing and the housing. This bearing bushing provides the necessary support structure that enables smooth rotation of the shank bushing, allowing even wear distribution across all surfaces while minimizing the complexity of the overall support structure required.
5Ease of operation
If a bearing bushing is added to support rotation, then smooth rotation is achieved, but device complexity increases
Solution Approach 1:
The bearing bushing serves as an intermediary element that enables smooth rotation between the shank bushing and housing with minimal additional complexity. It provides the necessary rotational support while maintaining a simple structural arrangement that does not significantly increase the overall device complexity.
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A shank sleeve assembly, a rock drilling machine, and a method. The assembly (26) is mountable around a shank adapter (8) in a rock drilling machine (6) and comprises a shank bushing (27) having two-piece configuration comprising a first bushing component (27a) and a second bushing component (27b) connectable against each other. The assembly further comprises a bearing bushing (30) arrangeable to surround the two-piece shank bushing and allowing rotation between the shank bushing and the bearing bushing.