Motor Control for Portable Drills Using Reverse Pulse
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Solution Overview
Problem
Conventional portable drilling machines lack efficient mechanisms to handle tool stickage and power management, particularly in situations where the tool is stuck, leading to reduced effectiveness and increased power consumption.
Innovation Solution
A control procedure for a portable drilling machine that includes a motor and drivetrain system, where activating a pushbutton causes the motor to rotate in one direction for a short duration (less than 100 ms) in the opposite direction to clear potential blockages, then switches to the correct rotation for operation, optimizing power usage and unstick the tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is activated directly in the correct rotation direction, then the tool can perform its intended function, but the tool may become stuck due to insufficient initial torque and power delivery is reduced
Solution Approach 1:
The motor is activated in reverse rotation direction before the intended operation to pre-accelerate the drivetrain components and reduce inertia effects. This preliminary action in opposite sense of rotation prepares the system for more effective power delivery during actual tool operation, preventing stickage and improving reliability.
2Ease of operation
If the motor runs continuously to maintain readiness, then the tool is immediately available for operation, but power consumption increases
Solution Approach 1:
Instead of continuous motor operation, the system uses periodic activation with a brief reverse rotation pulse when the trigger is activated. This periodic action mode maintains tool readiness while significantly reducing overall power consumption compared to continuous operation, as the motor only runs for short durations during actual use.
3Reliability
If the motor activation duration is extended to ensure tool unstickage, then tool stickage is reduced, but the response time for actual operation increases
Solution Approach 1:
The motor is activated in reverse rotation for a brief duration (less than 100 ms) which is sufficient to prevent tool stickage without extending the overall activation response time significantly. This partial action approach provides just enough preliminary motion to clear potential blockages while maintaining fast response for actual operation.
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 effectively manages power consumption, reduces the risk of tool stickage by pre-accelerating the motor before engaging the correct torque, and ensures high torque delivery when needed, enhancing operational efficiency and usability.
Implementation Method 1
a motor (5) and a drivetrain coupling the motor (5) with the tool retainer (2) for transmitting a torque
Data Source
AI summary
A machine tool has a tool retainer for retaining a tool, a motor and a drivetrain which couples the motor with the tool retainer for transmitting a torque. A system pushbutton is coupled with a motor control. When the system pushbutton is activated by a user, the motor control controls the motor in such a way that the motor turns in a first sense of rotation for a duration and then in a sense of rotation opposed to the first sense of rotation. The duration is shorter than 100 ms.