Driver-Drill Gearshift Sensing for Mode-Based Clutch Torque
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Solution Overview
Problem
Existing driver-drills lack the ability to select clutch-actuation torques in low-speed mode that are higher than those in high-speed mode, and they often require additional sensors to detect operating modes, which complicates the design and increases the size of the device.
Innovation Solution
A driver-drill with a speed change mechanism and a controlling means that allows for higher clutch-actuation torques in low-speed mode, using a torque-specifying means to set clutch-actuation torque within a high-low range, and incorporates sensors to detect operating modes without increasing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a driver-drill provides the same clutch-actuation torque range for both high-speed mode and low-speed mode, then the torque setting mechanism remains simple, but the device cannot achieve higher clutch-actuation torques in low-speed mode which are needed for high-torque applications
Solution Approach 1:
The patent implements dynamic clutch-actuation torque ranges that automatically adapt to the operating mode. The controller dynamically adjusts the clutch-actuation torque based on whether high-speed mode or low-speed mode is active, allowing higher torque ranges in low-speed mode without requiring manual reconfiguration or complex mechanical adjustment mechanisms.
Solution Approach 2:
The patent changes the operational parameters of the clutch-actuation torque based on the speed mode. The controller modifies the torque threshold parameters dynamically - using a first clutch-actuation torque range for high-speed mode and a second, higher clutch-actuation torque range for low-speed mode, enabling adaptability without adding mechanical complexity.
2Adaptability or versatility
If additional sensors are added to detect operating modes and enable different clutch-actuation torque ranges, then the device functionality is improved, but the device size and complexity increase
Solution Approach 1:
The system uses existing operational parameters (rotational speed, motor current) to self-determine the operating mode without requiring additional sensors. The controller automatically identifies whether high-speed mode or low-speed mode is active based on these inherent system states, enabling adaptive torque control without external detection devices.
Solution Approach 2:
The patent replaces potential mechanical or optical sensing systems with an electronic control system that uses existing electrical and rotational data. The controller substitutes complex sensor-based detection with algorithmic determination of operating mode based on motor current and rotational speed measurements already available in the system.
Data Source
AI summary
A rotary tool includes a motor having an axis of rotation extending in a forward-rearward direction of the rotary tool. A grip part is located below the axis of rotation in an up-down direction that is perpendicular to the forward-rearward direction. A planet gear is configured to be driven by the motor. An internal gear meshes with the planet gear and is movable in the forward-rearward direction to change a speed. A sun gear meshes with the planet gear, and an output shaft is configured to be rotationally driven by the sun gear. A sensor is configured to detect the forward-rearward movement of the internal gear, the sensor being disposed downward of the sun gear in the up-down direction.