Sliding-Contact Wave Generator With Displacing Sections for Low Torque
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Solution Overview
Problem
Sliding-contact-type wave generators require high rotational torque to generate wave motion in external gears, which is inefficient compared to rolling-contact-type wave generators, especially at high speeds.
Innovation Solution
A wave generator design featuring a rigid plug with an ellipsoidal outer surface and an annular displacement body with radially arranged displacing sections that can elastically displace, allowing for sliding contact and reduced torque requirements by generating wave motion through circumferential movement of the external gear's meshing position with a rigid internal gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a sliding-contact-type wave generator is used, then efficiency during high-speed rotation is improved, but rotational torque required to generate wave motion increases
Solution Approach 1:
The wave generator is divided into two functional components: a plug that provides the ellipsoidal profile and an annular displacement body with multiple displacing sections that contact the external gear. This segmentation allows the plug to rotate with minimal torque while the displacing sections generate the necessary wave motion, resolving the contradiction between low torque requirement and high-speed efficiency.
Solution Approach 2:
The annular displacement body acts as an intermediary between the plug and the external gear. It translates the rotational motion of the plug into radial displacement of the external gear, enabling wave motion generation with reduced rotational torque while maintaining sliding contact benefits for high-speed efficiency.
2Force
If a rolling-contact-type wave generator is used, then rotational torque is reduced, but efficiency during high-speed rotation decreases
Solution Approach 1:
Different parts of the wave generator have different contact characteristics: the interface between the plug and displacing sections uses sliding contact for low viscous resistance at high speeds, while the interface between the displacing sections and external gear uses controlled contact to generate wave motion. This local differentiation resolves the contradiction between torque requirements and high-speed efficiency.
3Ease of operation
If direct sliding contact between plug and external gear is used, then wave motion is generated, but high rotational torque is required
Solution Approach 1:
The displacing sections serve as intermediaries that convert the rotational motion of the plug into effective radial displacement of the external gear. This mediation reduces the direct torque burden on the plug while maintaining effective wave motion generation, as the displacing sections are positioned to leverage mechanical advantage.
Solution Approach 2:
The solution moves from direct radial contact to a two-stage transmission: first circumferential rotation of the plug, then radial displacement through the displacing sections. This dimensional transformation allows wave motion generation with reduced rotational torque by utilizing the mechanical advantage of the displacing section geometry.
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 reduces the rotational torque needed to generate wave motion in the external gear, improving efficiency during high-speed rotation by leveraging sliding contact and elastic displacement of the annular displacement body.
Implementation Method 1
each of the displacing sections is a rigid body in the radial direction of the annular displacement body and is connected so as to be able to elastically displace in the radial direction relative to the displacing sections adjacent thereto
Implementation Method 2
the plug-contacting sections are in a state of sliding contact with the plug-outer-circumferential surface of the plug
Data Source
AI summary
A wave generator for a strain wave gearing is provided with a rigid plug having an ellipsoidal plug-outer-circumferential surface, and a ring-shaped displacement body that is flexed to an ellipsoidal shape by the plug. The ring-shaped displacement body is provided with a plurality of radially arranged displacing sections. The plug-contacting surfaces of the displacing sections are in sliding contact with the plug-outer-circumferential surface and when the plug rotates, the displacing sections are repeatedly displaced in the radial direction. By the displacement of the displacing sections, wave motion is generated in an external gear. It is possible to achieve a wave generator capable of generating wave motion in the external gear with a small rotational torque.