Toroidal Slewing Drive With Nested Gearing for High Torque Density
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Solution Overview
Problem
Existing slewing drives face challenges in achieving high torque-to-mass and torque-to-volume ratios, particularly in compact actuators, making it difficult to achieve highly accurate positioning and rotation of heavy payloads.
Innovation Solution
A toroidal slewing drive design incorporating a slewing bearing, slewing output gear, and arc-shaped gear boxes with cluster gears and motors, allowing for increased torque through gear slot accommodations and multiple arc-shaped gear boxes, along with central passages for cables and slip rings, and utilizing brushless motors with a single driver for control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional gearing is used to increase output torque, then torque is improved, but device volume and mass increase
Solution Approach 1:
The patent places the drive output gear and cluster gears inside the gear slots of the slewing output gear, creating a nested configuration where smaller gears are positioned within the structural features of larger gears. This nesting allows multiple gearing elements to occupy overlapping spatial volumes, achieving high torque multiplication without proportionally increasing the overall device volume.
Solution Approach 2:
The invention transitions from traditional planar gear arrangements to a three-dimensional toroidal configuration where gears are distributed around a central axis at different radial distances and angular positions. The arc-shaped gear boxes and cluster gears utilize the third dimension (radial depth and angular distribution) to pack gearing elements more densely, achieving high torque in a compact volume.
2Force
If traditional gearing is used to increase output torque, then torque is improved, but device mass increases
Solution Approach 1:
The drive output gear and cluster gears are nested within the gear slots of the slewing output gear structure, allowing multiple gearing elements to share the same structural space. This reduces redundant material and achieves high torque multiplication with minimal additional mass.
Solution Approach 2:
The gear slots in the slewing output gear serve dual purposes: they provide structural support for the output gear while simultaneously housing the drive output gear and cluster gears. This multi-functionality eliminates the need for separate housing structures, reducing overall device mass.
3Force
If multiple arc-shaped gear boxes are used to increase torque, then torque is improved, but device complexity increases
Solution Approach 1:
Multiple arc-shaped gear boxes are merged into a single integrated structure that is equidistantly distributed around the central passage. The gear boxes share common structural elements and are synchronized through a single driver, reducing control complexity while maintaining high torque capability through parallel gearing paths.
Solution Approach 2:
The single driver controls multiple brushless motors that drive the arc-shaped gear boxes, creating a universal control system that manages multiple torque-generating elements. The gear boxes themselves serve multiple functions: torque multiplication, structural support, and spatial distribution of loading.
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
The design achieves higher torque per volume and improved torque ratios, reduced weight and size, and simplified control of multiple motors, enhancing torque and positioning accuracy.
Implementation Method 1
The motor drives the drive output gear through the plurality of cluster gears and the drive output gear engages the slewing output gear
Implementation Method 2
The motor is a brushed or a brushless motor
Data Source
AI summary
A toroidal slewing drive includes a slewing bearing, a slewing output gear and at least one arc-shaped gear box. The slewing bearing includes an inner ring and an outer ring which move relative to one another. The slewing output gear includes gear teeth between an upper gear slot and a lower gear slot and is mounted on one of the inner ring and the outer ring. The at least one arc-shaped gear box includes a motor, a drive output gear, and a plurality of cluster gears and drives the drive output gear through the plurality of cluster gears. The drive output gear engages the slewing output gear. A portion of at least one of the plurality of cluster gears occupies at least a portion of at least one of the upper gear slot and the lower gear slot.