Roller Bit Rotary Cutting Mechanism for Rock Breaking Efficiency
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Solution Overview
Problem
Conventional roller bits, including three roller and PDC bits, face issues such as premature bearing failure, low rock breaking efficiency, short service life, and difficulty in chip removal due to packed structures, leading to reduced penetration rates and wear resistance.
Innovation Solution
A roller bit design featuring a bit body with a roller and cutting teeth, where the included angle between the roller journal plane and the bit axis ranges from 0° to 90°, and a journal offset within specific limits, allowing for rotary cutting and improved sliding distances of teeth, enhancing rock breaking efficiency and bearing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional roller bits use impacting and crushing mechanism, then rock breaking can be achieved, but energy efficiency is low and rock breaking efficiency is reduced
Solution Approach 1:
The patent replaces the conventional impacting and crushing mechanical mechanism with a rotary cutting mechanism. The cutting teeth on the roller perform rotational cutting motion on the rock formation, transforming the rock breaking process from high-energy impact to more efficient rotational cutting, thereby improving energy efficiency while maintaining rock breaking capability
Solution Approach 2:
The patent changes the operational parameters of the bit by introducing a roller with cutting teeth that rotate at specific speeds and apply controlled pressure. The roller rotates in a direction that creates effective cutting motion, and the bit pressure is optimized to work with the rotational cutting mechanism, improving both energy efficiency and rock breaking efficiency simultaneously
2Speed
If three roller bit uses high cone/bit speed ratio, then roller rotating speed increases, but bearing service life decreases
Solution Approach 1:
The patent optimizes the cone/bit speed ratio parameter to a specific range (0.5-1.5) to balance roller rotating speed with bearing durability. The roller is designed with cutting teeth that can operate effectively at these controlled speeds, allowing sufficient roller rotation for efficient cutting while preventing excessive speeds that would damage the bearing
Solution Approach 2:
The patent introduces a dynamic roller design where the roller can rotate independently at controlled speeds relative to the bit rotation. The roller's rotation is dynamically adjusted to optimize cutting performance while keeping the bearing load within acceptable limits, thereby extending bearing service life while maintaining effective cutting speed
3Stability of the object's composition
If roller bit uses packed structure, then chip removal becomes difficult, but structural compactness is achieved
Solution Approach 1:
The patent segments the roller structure into multiple cutting teeth arranged in specific patterns. This segmentation allows chips to be removed more effectively between the teeth while maintaining the overall compact structure. The teeth are positioned to create gaps that facilitate chip evacuation without significantly increasing the overall bit size
Solution Approach 2:
The patent addresses chip removal by utilizing the rotational dimension of the roller. The rotating motion creates dynamic pathways for chip removal in the axial and radial directions, allowing chips to be ejected from the packed structure during rotation without requiring larger gaps in the static structure
4Duration of action of stationary object
If teeth are provided with high wear resistance, then service life increases, but penetration rate decreases
Solution Approach 1:
The patent optimizes the bit pressure parameter to work synergistically with the wear-resistant teeth. By controlling the pressure within a specific range and applying it dynamically during rotation, the system achieves effective cutting with fewer teeth worn, thereby extending service life while maintaining high penetration rates through efficient energy utilization
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 roller bit achieves high rock breaking efficiency, extended service life, balanced wear patterns, and improved penetration rates by utilizing the rotary cutting mechanism, which balances the load on teeth and reduces the cone/bit speed ratio, resulting in better dynamic performance and gauge protection.
Implementation Method 1
breaks the rocks by impacting, crushing and cutting by rotary cutting
Implementation Method 2
breaks the rocks by impacting and crushing
Implementation Method 3
breaks the rocks by impacting and crushing
Implementation Method 4
a bearing and sealing structure
Data Source
AI summary
A roller bit for rock breaking by rotary cutting comprises: a bit body (1), a roller (2) and cutting teeth (3). An included angle β between a roller journal plane of the bit body and the roller on a bit axis has a range of 0°<β<90°, a journal offset S has a range of −D/2<S<D/2, wherein D represents a diameter of the bit. Inner row of teeth rings on the bit cuts a center of a borehole bottom, and each row of teeth ring is capable of scraping a borehole wall, and thus the bit has good effects of gauge protection and sidetracking.