Planetary Gear Driver-Drill for High Torque in Short Length
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Solution Overview
Problem
Existing driver-drills face challenges in achieving high torque and compact design, as they often compromise between torque output and overall length, with existing solutions not efficiently addressing the need for both high torque and reduced length.
Innovation Solution
The driver-drill incorporates a motor with a stator and rotor, a spindle, a chuck, and a three-stage variable-speed speed-reducing mechanism, which includes a first, second, and third planetary-gear mechanism, allowing for higher torque output while maintaining a compact length by optimizing the gear ratios and housing design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a speed-reducing mechanism is added to increase output torque, then the torque of the output part increases, but the overall length of the driver-drill increases
Solution Approach 1:
The patent employs a planetary gear mechanism where gears are nested within each other - the sun gear at the center, planet gears surrounding it, and a ring gear enclosing the planet gears. This nested arrangement allows multiple gear stages to be compacted into a small volume, achieving significant torque multiplication (speed reduction) while maintaining a compact overall length of 210 mm or less.
Solution Approach 2:
The planetary gear mechanism transforms the linear arrangement of gears into a radial/dimensional configuration. Instead of gears arranged in a straight line (which would increase length), the patent uses the radial dimension with planet gears rotating around the sun gear, achieving torque multiplication in a compact axial space while keeping the driver-drill length under 210 mm.
2Force
If the rotational speed of the rotor is reduced to increase torque, then the torque increases, but the productivity decreases
Solution Approach 1:
The patent implements a variable-speed mechanism that allows dynamic adjustment of the speed reduction ratio. The planetary gear mechanism can operate in different configurations (engaging different planet gears or adjusting the engagement state) to provide multiple speed-torque combinations, enabling the user to optimize between rotational speed and torque based on the specific application requirements, thus maintaining productivity while achieving high torque when needed.
Solution Approach 2:
The patent changes the transmission ratio parameter of the speed-reducing mechanism to achieve different output characteristics. By adjusting the engagement state of the planetary gears or changing the gear ratio configuration, the system can vary the balance between rotational speed and torque output, allowing high torque (160 N·m or more) to be achieved only when required, while maintaining higher speeds for other operations to preserve productivity.
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 configuration enables the driver-drill to achieve a maximum fastening torque of 160 N·m or more while maintaining an overall length of 210 mm or less, providing a balanced solution for both high torque and compactness.
Implementation Method 1
a speed-reducing mechanism, which is configured to rotate the output part at a rotational speed that is lower than the rotational speed of the rotor but at a higher torque. The speed-reducing mechanism may be a three-stage, variable-speed mechanism.
Implementation Method 2
The speed-reducing mechanism may be a three-stage, variable-speed mechanism comprising: a first planetary-gear mechanism comprising: a first-stage portion comprising a plurality of first planet gears disposed around a sun gear rotated by the rotor and a first internal gear disposed around the plurality of first planet gears; and a second-stage portion, the speed-reduction ratio of which differs from that of the first-stage portion and comprising a plurality of second planet gears disposed around the sun gear and a second internal gear disposed around the plurality of second planet gears
Data Source
AI summary
A driver-drill (1) includes a motor (6) having a stator (61) and a rotor (62); an output part (8) including: a spindle (81), which is disposed more forward than the motor and, in response to application of a rotational force transmitted from the rotor, is rotated around a rotational axis (AX) extending in the front-rear direction; and a chuck (82), which is mounted on the spindle; and a speed-reducing mechanism (30), which is configured to rotate the output part at a rotational speed that is lower than the rotational speed of the rotor but at a higher torque. The maximum fastening torque of the output part is 160 N·m or more.