Nested Planetary Torque Tool for Compact High-Ratio Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional torque output tools with three-layer planetary gear trains are not conducive to reducing the overall dimension while achieving sufficient torque output, and double-layer planetary gear trains compromise gear strength for high or low gear ratios.
Innovation Solution
A torque output tool utilizing a double-layer planetary gearset with a first and second planetary gearset, allowing switching between two gear ratios, and a torque adjustment mechanism to optimize rotational speed and torque output, reducing the overall dimension and ensuring gear strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a three-layer planetary gear train is used to achieve sufficient gear ratio for deceleration, then the deceleration requirement is satisfied, but the overall dimension of the torque output tool increases
Solution Approach 1:
The patent employs a nested planetary gear structure where a first planetary gearset is positioned inside a second planetary gearset, with the sun gear of the first gearset concentric with and inside the planet gears of the second gearset. This nesting arrangement allows two complete planetary stages to be compacted into a smaller axial space, achieving high deceleration ratios without proportionally increasing the overall tool dimension.
Solution Approach 2:
The invention transitions from a traditional sequential arrangement of planetary gearsets along the axial direction to a radial nesting configuration. By organizing the first planetary gearset within the radial space of the second planetary gearset, the design utilizes radial dimension more effectively, reducing the axial length requirement while maintaining the necessary gear ratio for deceleration.
2Speed
If a double-layer planetary gear train is used to achieve high gear ratio, then the gear ratio requirement is met, but the gear strength decreases
Solution Approach 1:
The patent applies different structural configurations to different parts of the planetary gear system. The first planetary gearset uses a traditional sun-planet-ring configuration, while the second planetary gearset employs a carrier-based mounting for its planet gears. This localized structural optimization allows each gearset to be designed for its specific functional requirements, maintaining gear strength while achieving the desired high gear ratio.
Solution Approach 2:
The invention uses composite structural design where the planetary gear system combines multiple gearsets with different mounting configurations (sun gear mounted for first gearset, carrier mounted for second gearset). This composite approach allows the system to achieve high gear ratios while distributing mechanical loads across multiple engagement points, thereby maintaining overall gear strength despite the reduced size.
3Length of stationary object
If a double-layer planetary gear train is used to achieve low gear ratio, then the overall dimension is reduced, but the deceleration requirement cannot be satisfied
Solution Approach 1:
The patent merges two planetary gearsets into a single integrated transmission assembly where the first planetary gearset (with sun gear) and second planetary gearset (with carrier-mounted planets) work together. By combining these two stages in a nested configuration, the system achieves a compounded gear ratio that provides sufficient deceleration capability while keeping the overall dimension compact, as both gearsets share the same central axis and radial space.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A torque output tool includes an output shaft, a motor, a transmission assembly, and a gearbox. The output shaft is used for outputting torque. The motor is used for driving the output shaft to rotate around a first axis. The transmission assembly is used for transmitting output of the motor to the output shaft. The gearbox is used for accommodating the transmission assembly. The transmission assembly includes a first planetary gearset and a second planetary gearset. The transmission assembly is capable of being switched to a first state and a second state such that the transmission assembly outputs a first gear ratio or a second gear ratio separately, where the first gear ratio is greater than the second gear ratio. When the transmission assembly outputs the first gear ratio, a rotational speed of the output shaft is greater than or equal to 300 r/min and less than or equal to 800 r/min. A length of the gearbox in an axial direction of the first axis is configured to be greater than or equal to 38 mm and less than or equal to 46 mm.