Piston Guiding Element With Hydraulic Bearing Cooling
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Solution Overview
Problem
Existing rock drilling machines face challenges with pressure peaks on front bearings of the percussion piston, which can be harmful and are not adequately addressed by existing solutions.
Innovation Solution
A piston guiding element with a sleeve-like design is introduced, featuring separate bearing sleeves with slide bearing material and a braking recess. Hydraulic fluid is conveyed between the axial sections of the bearing sleeves, reducing pressure peaks and cooling the bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a braking recess is used to stop the piston, then the piston can be effectively decelerated, but pressure peaks occur on the front bearings which are harmful
Solution Approach 1:
A piston guiding element is introduced as an intermediary component between the piston and the machine body. This guiding element includes bearing surfaces that guide the piston during deceleration, distributing the pressure that would otherwise concentrate on the front bearings. The guiding element effectively mediates the interaction between the piston and braking recess, eliminating harmful pressure peaks while maintaining effective deceleration.
Solution Approach 2:
The piston guiding element provides localized bearing surfaces with specific friction characteristics at the front of the piston. By creating a localized zone with optimized tribological properties, the pressure is distributed across the guiding element's bearing surfaces rather than being concentrated on the front bearings, thus reducing harmful pressure peaks while maintaining effective braking.
2Reliability
If bearing material is used to support the piston, then bearing support is provided, but temperature increases due to friction and pressure
Solution Approach 1:
Hydraulic fluid is introduced to cool the bearing surfaces of the piston guiding element. The fluid flows through channels in the guiding element, absorbing heat generated by friction between the piston and bearing surfaces. This hydraulic cooling system effectively removes heat from the bearings, maintaining reliable bearing support while preventing excessive temperature increase.
Solution Approach 2:
The temperature of the bearing surfaces is controlled by changing the thermal parameters of the system - specifically by introducing cooling fluid that absorbs heat. The cooling fluid's temperature and flow rate are adjusted to maintain optimal bearing temperature, allowing reliable bearing support without excessive heat buildup.
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 peaks on the bearings, lowers their temperature, and simplifies manufacturing and mounting, while maintaining the structural integrity and operational efficiency of the rock drilling machine.
Implementation Method 1
Hydraulic fluid can be conveyed by means of the at least one radial opening and the first groove between the mentioned two successive slide bearing sections
Implementation Method 2
Hydraulic pressure fluid is directed between the two axial bearing sections
Implementation Method 3
Both sections comprise slide bearing material
Data Source
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 piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.