Keyed Drill Bit Connection for Wear Reduction

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Solution Overview

Problem

Conventional drilling tools with splined connections are prone to excessive wear, difficult to manufacture, and require additional space and length, leading to increased costs and operational challenges, especially in harsh environments.

Innovation Solution

A keyed connection system between the drill bit and driver sub, featuring a transverse member and opening in the drill bit, allowing for torque transmission and axial movement, which reduces wear and manufacturing complexity while minimizing space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a splined connection is used between the drill bit and driver sub, then torque can be transmitted to the drill bit, but the connection is subject to excessive wear and early failure in harsh environments

Engineering Contradiction:

Improveconnection durabilityVSAvoidwear

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The connection is segmented into a key element and a keyway, replacing the continuous splined interface with discrete mating surfaces. This segmentation reduces the contact area subject to wear and allows for easier replacement of worn components without replacing the entire connection assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The key element is designed as a replaceable component that can be easily replaced when worn, rather than replacing the entire splined connection assembly. This allows for cost-effective maintenance in harsh drilling environments where wear is inevitable.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Power

If a splined connection is used between the drill bit and driver sub, then torque can be transmitted, but the connection is difficult to manufacture, making the drilling tool and drill bit more expensive

Engineering Contradiction:

Improvetorque transmissionVSAvoidmanufacturing complexity

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The complex splined interface is replaced with simpler key and keyway elements that are easier to manufacture. The keyway can be created with standard milling operations, and the key is a simple rectangular or shaped bar, both of which are more straightforward to produce than precision splines.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The keyway geometry is a simplified copy of the essential function of splines (torque transmission) without replicating their complexity. The keyway provides the necessary torque transmission capability through a simpler, more manufacturable geometry.

Inventive Principle:

Principle #26Copying

3Force

If two separate connections are used (splined connection for torque and retaining rings for axial force), then both torque and axial force can be transmitted, but additional space within the drilling tool is consumed and the tool requires added length

Engineering Contradiction:

Improveaxial force transmissionVSAvoiddrilling tool length

Core Design Contradiction:

ForceVSLength of moving object

Solution Approach 1:

The key connection merges the functions of torque transmission and axial force transmission into a single integrated element. The key simultaneously resists rotational forces (torque) and axial forces, eliminating the need for separate retaining rings and reducing the overall tool length.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The key element is designed to perform multiple functions: transmitting torque, resisting axial forces, and positioning the drill bit axially. This multi-functional design replaces the need for multiple specialized components, saving space and reducing tool length.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Power

If two separate connections are used (splined connection for torque and retaining rings for axial force), then both torque and axial force can be transmitted, but the drilling tool and drill bit are more expensive

Engineering Contradiction:

Improvetorque transmissionVSAvoidnumber of connections

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

5Force

If retaining rings are used for the second connection, then axial force can be transmitted to the drill bit, but the retaining rings become difficult to remove after use

Engineering Contradiction:

Improveaxial force transmissionVSAvoidretaining ring removal

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7395883B2Keyed connection for drill bit

Publication Date: 2008.07.08 ROCKMORE INT

AI summary

A portion of a drilling tool having a drill bit driven in a rotating motion and in an axial percussion motion comprises a keyed connection between the drill bit and a driver sub that receives the drill bit. The keyed connection comprises a transverse member coupling the drill bit to a driver sub having a bore within which the drill bit is received. The driver sub has a pair of opposed openings and the bit has an axial slot. The openings and the slot are dimensioned to receive the transverse member. The keyed connection transmits force to the drill bit to drive the drill bit during operation and removably secures it in the driver sub.