Piston Guiding Sleeve Layout for Bearing Pressure Peak Relief
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Solution Overview
Problem
Existing rock drilling machines face challenges in managing pressure peaks on bearings, particularly when stopping the percussion piston, leading to potential damage and inefficiencies in hydraulic impact devices.
Innovation Solution
A sleeve-like piston guiding element is introduced, featuring separate bearing sleeves with slide bearing material and a braking recess, where hydraulic fluid is conveyed between axial sections to mitigate pressure peaks and cool the bearings, facilitating easier manufacturing and mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydraulic fluid is conveyed through the braking recess to cool the bearings, then the temperature of the bearings is reduced, but the pressure peaks on the bearings increase significantly
Solution Approach 1:
The bearing support structure is divided into two separate axial sections (first and second axial sections) with distinct functions. The first axial section is dedicated to hydraulic fluid conveyance for cooling, while the second axial section provides bearing support. This segmentation allows the cooling function to be performed without subjecting the bearing to harmful pressure peaks.
Solution Approach 2:
A piston guiding element acts as an intermediary component between the braking recess and the bearing. This element includes a first groove with radial openings that convey hydraulic fluid from the braking recess to the first axial section, thereby mediating the cooling function while protecting the bearing from direct exposure to high pressure peaks.
2Reliability
If a complex bearing structure is used to manage pressure peaks, then the bearing reliability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The piston guiding element merges multiple functions into a single integrated component: it provides bearing support through the axial sections, conveys hydraulic fluid through the first groove and radial openings, and guides the piston. This merging simplifies the overall structure compared to using separate components for each function while maintaining bearing reliability.
Solution Approach 2:
The piston guiding element is designed as a multi-functional component that simultaneously serves as a bearing support, a fluid conduit, and a piston guide. The axial sections provide bearing support, the first groove and radial openings provide fluid conveyance, and the overall structure guides the piston movement, thereby reducing the number of separate components needed.
3Ease of manufacture
If integrated bearing and cooling structure is used, then the manufacturing and mounting is simplified, but the ability to effectively manage pressure peaks may be compromised
Solution Approach 1:
The piston guiding element exhibits local quality by having different structural characteristics in different axial sections. The first axial section is optimized for hydraulic fluid conveyance with appropriate groove and opening configurations, while the second axial section is optimized for bearing support. This localized optimization allows each section to perform its specific function effectively while maintaining overall simplicity.
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 effectively reduces pressure peak magnitudes on bearings, lowers temperature, and simplifies the structure and installation process, enhancing the durability and efficiency of rock drilling machines.
Implementation Method 1
Hydraulic fluid is conveyed between the axial sections so as to reduce magnitudes of pressure peaks directed to the bearings
Implementation Method 2
temperature of the bearings can be lowered when hydraulic fluid is conveyed to the bearings elsewhere than form the braking recess
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The element (20) comprises a braking recess (16) at its rear end (24). The element further comprises at least one bearing sleeve (29) which is provided with two axially successive slide bearing sections (AS1, As2). Hydraulic fluid is conveyed between the slide bearing sections via a feed system (21).