Guiding Support for Rock Drilling Machine
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Solution Overview
Problem
Existing rock-drilling machines experience unreliable guiding in weak rock formations, resulting in an inconsistent curve radius that does not proportionally relate to the angular deflection between the drill and string portion centre axes, leading to inefficient drilling progress.
Innovation Solution
A guiding support with a centric drive shaft, flanges, and freely rotating wheel frames with guiding wheels is introduced between the drill bit and guiding joint, allowing the wheels to bear against the borehole wall and transmit torque independently of the drill bit's direction, reducing radial forces on weak rock and maintaining a constant curve radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional guiding joint is used to change the angle between drill-portion centre axis and string-portion centre axis, then directional control is achieved in hard rock, but the curve radius achieved in weak rock is not proportional to the angular deflection, leading to unreliable guiding
Solution Approach 1:
A guiding support with guiding wheels is introduced as an intermediary element between the drill portion and the borehole wall. The guiding wheels bear against the borehole wall to provide lateral support and enable reliable directional control in weak rock formations, making the curve radius proportional to the angular deflection at the guiding joint.
Solution Approach 2:
The invention changes the physical state of the drilling system by adding a mechanical support structure (guiding support with wheels) that alters how the drill bit interacts with weak rock. This parameter change transforms the unreliable guiding in weak rock into controlled directional drilling by providing external lateral support through the guiding wheels bearing against the borehole wall.
2Ease of operation
If the drill portion is turned to achieve angular deflection for directional drilling, then the drill-portion centre axis takes an angle relative to the string-portion centre axis, but radial forces are applied to weak rock causing inconsistent curve radius
Solution Approach 1:
The guiding support acts as a counterbalancing structure that opposes the radial forces applied to weak rock during directional drilling. By bearing against the borehole wall, the guiding support counteracts the destabilizing radial forces, maintaining stable borehole geometry and consistent curve radius proportional to the angular deflection.
3Power
If the guiding joint transmits torque from the drill bit, then the drilling function is maintained, but the guiding function becomes unreliable in weak rock formations
Solution Approach 1:
The drilling system is segmented into distinct functional components: the guiding joint for torque transmission and angular deflection, and the guiding support with guiding wheels for lateral stabilization. This segmentation allows the guiding joint to maintain torque transmission while the guiding support independently provides reliable guiding function in weak rock formations.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A guiding device for a rock-drilling machine (1), the rock-drilling machine (1) including a drill portion (4) with a drill bit (10) and a drill-portion centre axis (26), and a string portion (6) with a string-portion centre axis (28), the drill-portion (4) and the string-portion (6) being inter-connected by means of a guiding joint (8), and the drill portion (4) being provided with, between the drill bit (10) and the guiding joint (8), a guiding support (16) which is arranged to bear against the borehole wall (56) of a borehole (2).