Low-Profile Wave Strain Gearbox With Segmented Torque Transmission
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Solution Overview
Problem
Existing wave strain drives are inherently high-profile devices due to the design constraints of flexible splines needing to be both flexible and strong, making them unsuitable for applications requiring low-profile gearboxes, such as slewing drives in robotics.
Innovation Solution
The design separates the flexible and strong characteristics of the flexible spline into multiple elements, including a deformable gear band and a low profile fixed spline, with a flexible-band-compensating rigid torque transmitter to transmit torque efficiently, allowing for a significantly reduced profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a flexible spline is used to transmit torque, then the drive can accommodate deformation and achieve high torque transmission, but the profile height increases making it unsuitable for low-profile applications
Solution Approach 1:
The flexible spline is segmented into multiple rigid or semi-rigid elements (spline blocks) connected by flexible joints. This segmentation allows each element to maintain structural strength for torque transmission while the joints provide the necessary flexibility, eliminating the need for a tall monolithic flexible spline structure.
Solution Approach 2:
Flexible joints or connectors serve as intermediaries between the rigid spline elements. These intermediaries transmit torque while accommodating deformation, replacing the traditional tall flexible spline structure with a compact assembly of rigid elements and flexible connectors.
2Strength
If the flexible spline is made stronger to transmit high torque, then torque transmission improves, but the structure becomes less flexible and the profile increases
Solution Approach 1:
By dividing the spline into rigid segments, each segment can be optimized for strength to handle high torque, while the flexible joints between segments provide the necessary adaptability and flexibility for deformation accommodation.
Solution Approach 2:
Different parts of the spline structure have different properties: the spline elements are made rigid for strength and torque transmission, while the connecting joints are made flexible for adaptability. This local differentiation resolves the contradiction between overall strength and flexibility.
3Ease of manufacture
If the flexible spline structure is simplified, then manufacturing becomes easier, but the ability to transmit high torque is reduced
Solution Approach 1:
The segmented structure allows each spline element to be manufactured as a simple, standardized component, simplifying production. The elements can be manufactured using conventional processes and then assembled, reducing overall design complexity while maintaining high torque transmission capability through the modular architecture.
Solution Approach 2:
The spline system transitions from a static monolithic structure to a dynamic modular assembly. The rigid elements provide structural integrity for torque transmission, while the flexible joints enable dynamic adaptation, simplifying manufacturing through standardization while preserving strength.
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 results in a low-profile wave strain drive that can be packaged in a smaller form factor, capable of transmitting high torque and accommodating larger diameters, suitable for applications like robotic arms with reduced design complexity.
Implementation Method 1
The wave generator deforms the deformable gear band within the low profile fixed spline
Data Source
AI summary
A wave transmission gearbox includes an output wheel, a deformable gear band, a low profile fixed spline, a wave generator, and a flexible-band-compensating rigid torque transmitter. The deformable gear band has external teeth transmitting relative torque motion to the output wheel, and is as wide as its external teeth. The low profile fixed spline has internal teeth meshing with the external teeth of the deformable gear band, and has a width which is a function of the width of the deformable gear band. The wave generator deforms the deformable gear band within the low profile fixed spline to generate relative torque motion between the deformable gear band and the low profile fixed spline. The flexible-band-compensating rigid torque transmitter transfers relative torque motion from the deformable gear band to the output wheel.