Torque-Responsive Drill Lubrication for Cutting Force Control

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Solution Overview

Problem

Existing drilling technologies face inefficiencies in lubricant management, leading to excessive lubricant consumption and pollution during drilling operations, particularly in aeronautics, where drills are used for drilling aircraft structures. Current solutions, such as mechanical and electronic systems, either dampen vibratory feed drilling or are fragile and difficult to calibrate.

Innovation Solution

A drill design that utilizes mechanical means to determine torque exerted on the spindle during drilling, controlling the lubricant pump's flow rate based on this torque, ensuring lubrication only during active drilling phases and adjusting flow rates according to cutting forces, using a pneumatic motor and epicyclic gear train to efficiently measure and regulate lubricant distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous lubrication is provided during all drilling phases (approach, withdrawal, through-drilling), then the cutting tool is always lubricated, but excessive lubricant consumption and pollution occur

Engineering Contradiction:

Improvelubrication reliabilityVSAvoidlubricant consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies a dynamic control system where the lubricant pump is activated only during active drilling phases. The system uses a sensor to detect drilling status and dynamically switches the pump between on and off states, preventing lubricant waste during approach, withdrawal, and through-drilling phases while ensuring adequate lubrication during material removal

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback mechanism where a sensor detects the drilling phase (approach, material removal, withdrawal, through-drilling) and provides this information to the control system. Based on this feedback, the control system activates or deactivates the lubricant pump accordingly, optimizing lubricant consumption while maintaining reliability

Inventive Principle:

Principle #23Feedback

2Reliability

If mechanical means are used to detect torque and control lubrication, then the system is robust and simple, but the ability to detect precise torque values is limited

Engineering Contradiction:

Improvesystem robustnessVSAvoidtorque detection precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent transforms the torque detection problem from measuring precise torque values to detecting torque threshold conditions. The mechanical detection system uses a spring-loaded mechanism that activates when torque exceeds a predetermined threshold, indicating active drilling. This parameter transformation allows simple mechanical means to provide reliable detection without requiring high measurement precision

Inventive Principle:

Principle #35Parameter changes

3Reliability

If lubrication is provided during approach and withdrawal phases, then the cutting tool is protected, but unnecessary lubricant is wasted

Engineering Contradiction:

Improvecutting tool protectionVSAvoidlubricant waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies periodic action by providing lubrication only during specific periods (active drilling phases) and stopping during other periods (approach, withdrawal, through-drilling). The lubricant pump operates intermittently based on detected drilling phase, ensuring tool protection when needed while eliminating waste during non-drilling phases

Inventive Principle:

Principle #19Periodic action

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 approach reduces lubricant consumption and pollution by delivering lubricant only during material removal phases, adapts flow rates to cutting forces, and provides a robust and efficient solution in challenging environments, minimizing idle lubrication and associated costs.

Implementation Method 1

This start button incorporates a spring-based return device enabling it to return to its resting state when the operator stops the test

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

These drills are generally provided with a pneumatic motor to drive the drill spindle in motion

Methodology Applied

Scientific EffectPneumatic pressure: Pressure Increase

Implementation Method 3

there are known pneumatic drills comprising a lubricant pump feeding a lubricant distribution channel

Methodology Applied

Scientific EffectPneumatic pumping: Pump

Implementation Method 4

using a pneumatic motor and epicyclic gear train to efficiently measure and regulate lubricant distribution

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS10994344B2Drill comprising mechanical elements for regulating the lubrication flow rate according to the cutting forces

Publication Date: 2021.05.04 SETI TEC

AI summary

A drill including a drill spindle capable of driving a cutting tool in movement. The drill has at least one channel for distributing a lubricant to the cutting tool, a pump to supply the channel with lubricant and control element(s) for controlling the flow rate of the pump. Such a drill further has mechanical element(s) for determining at least one piece of information representing the torque exerted on the spindle along its axis during drilling. The control element(s) act on the flow rate of the pump as a function of the torque exerted on the spindle along its axis during drilling.