Steering Joint for Directional Control of Rock Drilling Machines
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Solution Overview
Problem
Existing directional control methods for rock-drilling machines result in boreholes with a helical shape, making further movement and underreaming difficult, especially in long boreholes, due to fixed angle rotation of drill bits relative to the feeding rod.
Innovation Solution
A steering joint with a fixed steering axis perpendicular to the feeding rod's center axis, connected to an intermediate housing and actuated by a hydraulic system, allows controlled pivoting of the drill bits and motor, preventing excessive rotation and enabling precise directional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drill bits are rotated at a fixed angle relative to the feeding rod to achieve directional control, then the desired drilling direction is achieved, but the borehole exhibits a helical shape making further movement difficult
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed-angle rotation method with a dynamic steering joint that allows continuous adjustment of the drill bit angle. The steering joint enables the drill bit assembly to pivot smoothly along a controlled arc, maintaining optimal drilling angle while eliminating the helical borehole problem caused by fixed-angle rotation.
Solution Approach 2:
The patent implements parameter changes by transitioning from a fixed rotational angle to a variable steering angle. The steering joint mechanism allows the drilling unit to change its orientation parameter dynamically during operation, enabling precise directional control without creating helical boreholes, thus resolving the contradiction between directional precision and ease of movement.
2Measurement precision
If the drill bits are rotated at a fixed angle relative to the feeding rod, then directional control is achieved, but the borehole shape becomes helical affecting subsequent underreaming
Solution Approach 1:
The steering joint provides dynamic angle adjustment capability, allowing the drill bit assembly to maintain a consistent optimal angle relative to the borehole axis during both drilling and subsequent underreaming operations. This eliminates the helical borehole shape that complicates underreaming, while preserving precise directional control through controlled pivoting motion.
Solution Approach 2:
The patent changes the operational parameter from fixed rotation angle to variable steering angle controlled by the hydraulic system. This parameter change enables the drilling unit to adapt its orientation during different operational phases (drilling vs. underreaming), ensuring optimal borehole geometry for both operations without the helical shape problem.
3Measurement precision
If the drilling unit is controlled by fixed angle rotation, then directional drilling is achieved, but the feeding rod rotates excessively beyond springing rotation
Solution Approach 1:
The steering joint introduces a dynamic pivoting mechanism that replaces the excessive rotation of the feeding rod. Instead of rotating the entire feeding rod beyond its springing limit, the steering joint allows controlled pivoting of the drill bit assembly about a steering axis, maintaining torque within acceptable limits while achieving precise directional control.
Solution Approach 2:
The steering joint acts as an intermediary mechanism between the feeding rod and the drill bits. It transfers the directional control function from the feeding rod rotation to a dedicated pivoting joint, preventing excessive feeding rod rotation and its associated torque problems while maintaining precise directional control through the intermediate steering mechanism.
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
This solution enables precise directional control of the drilling unit, reducing the helical shape issue and facilitating easier movement and underreaming of boreholes, even in long and narrow passages.
Implementation Method 1
An actuator is connected between the axle mount and the bearing housing and is arranged to pivot the bearing housing about the steering axle and relative to the axle mount. The actuator is supplied with pressurized fluid from a circulation pump via a control valve.
Data Source
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AI summary
A method for the directional control of a rock-drilling ma-chine, the drilling unit (1) of the rock-drilling machine, which is located in a borehole (2), comprising at least a pi-lot drill bit (6) or an underreamer drill bit (8), the drill bit(s) (6, 8) being driven by an electric motor (10) via a gearbox (12), and the drill bit(s) (6, 8) being moved into the rock (3) by means of a feeding rod (4) extending from a feeding machine at the outside the borehole (2), and the drill bit(s) (6, 8), gearbox (12) and motor (10) being pivoted in a controlled manner about a steering axis (18) which is approximately perpendicular to the center axis (26) of the feeding rod (4).