Rotary Gearbox Segmented Housing and Sealing Design
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Solution Overview
Problem
Conventional rotary drilling rigs face issues with gearbox housing damage due to shear forces and misalignment, and sealing arrangement wear in the rotary joint, leading to reduced equipment lifespan and efficiency.
Innovation Solution
A rotary gearbox design with a gear train portion isolated from shear forces and a sealing arrangement featuring a piloting feature and multiple annular seals to extend the life of the sealing arrangement, and a three-roller bearing design to reduce deflection and improve load capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the gearbox housing is directly connected to the guide to transfer pull-down and pull-up forces, then the structural simplicity is improved, but the gearbox housing suffers from bending and flexing due to shear forces, resulting in damage to bolted joints and misalignment of the gear train
Solution Approach 1:
The gearbox housing is divided into two distinct portions: a gear train portion housing the gears and a mounting portion for attaching to the guide. This segmentation allows each portion to be optimized independently - the gear train portion is isolated from shear forces while the mounting portion handles the mechanical loads, preventing bending and flexing of the housing.
Solution Approach 2:
The mounting portion is extracted and positioned away from the gear train portion, spaced at a distance that isolates the gear train from the shear forces generated during pull-down and pull-up operations. This extraction removes the harmful forces from the vicinity of the sensitive gear train components.
2Reliability
If the sealing arrangement is positioned to provide fluid communication between stationary and rotatable pipes, then fluid sealing function is achieved, but the sealing arrangement is exposed to abrasive material from high-pressure flow, causing wear and failure
Solution Approach 1:
The patent introduces an intermediary flow path where fluid exits the stationary pipe downstream from the sealing arrangement and enters the rotatable pipe. This intermediary positioning ensures that abrasive material in the high-pressure flow does not directly contact the sealing arrangement, reducing wear and extending its operational life while maintaining effective fluid sealing.
3Volume of moving object
If the mounting surface is positioned close to the gear train portion, then the structural compactness is improved, but the gear train portion is subjected to shear forces and bending, causing misalignment and damage to gears and bearings
Solution Approach 1:
The gearbox housing is segmented into a gear train portion and a mounting portion that are spatially separated. The mounting portion is positioned away from the gear train portion, creating a distance that prevents shear forces from affecting the gear train alignment while maintaining functional integration of the overall structure.
Data Source
AI summary
A rotary gear box for a rotary drill rig having a rotary joint that includes a first conduit having a first end portion defining an exit, a second conduit having a second end portion defining an inlet, and a sealing arrangement positioned radially between the first end portion of the first conduit and the second portion of the second conduit. The second conduit is rotatable relative to the first conduit and is arranged coaxial with the first conduit. The first end of the first conduit is received within the second end of the second conduit such that the exit of the first conduit is downstream from the sealing arrangement.