Sliding-Contact Wave Generator With Radial 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 ellipsoidal plug and an annular displacement body with radially arranged displacing sections that elastically displace in the radial direction, allowing for sliding contact with the plug's outer surface, reducing the torque required to generate wave motion by positioning plug-contacting sections inside external-gear-contacting sections.
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 segmented into a plug and multiple displacing sections arranged radially. Each displacing section independently contacts the external gear, distributing the torque load across multiple contact points and reducing the total rotational torque required while maintaining sliding contact efficiency
Solution Approach 2:
The displacing sections act as intermediary elements between the plug and the external gear. These sections transmit the sliding contact motion from the plug to the external gear, enabling wave generation with reduced torque by mediating the force transmission through elastic deformation
2Force
If rolling bodies are used in a rolling-contact-type wave generator, then rotational torque is reduced, but efficiency during high-speed rotation decreases
Solution Approach 1:
The invention replaces the rolling contact mechanism with a sliding contact mechanism. The displacing sections slide against the external gear teeth rather than rolling, eliminating rolling resistance and improving high-speed efficiency while using elastic deformation to reduce the torque penalty associated with sliding contact
3Reliability
If displacing sections are positioned outside, then external gear contact is improved, but torque requirement increases
Solution Approach 1:
The displacing sections are positioned in the radial dimension inside the external gear contact point, closer to the rotation axis. This radial repositioning reduces the moment arm and thus the torque required, while the sections still effectively contact and displace the external gear teeth through elastic deformation
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 significantly reduces the rotational torque needed to generate wave motion in the external gear, enhancing 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 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
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
A wave generator (5) for a strain wave gearing (1) is provided with a rigid plug (11) having an ellipsoidal plug-outer-circumferential surface (12), and a ring-shaped displacement body (13) that is flexed to an ellipsoidal shape by the plug (11). The ring-shaped displacement body (13) is provided with a plurality of radially arranged displacing sections (15). The plug-contacting surfaces (16) of the displacing sections (15) are in sliding contact with the plug-outer-circumferential surface (12) and when the plug (11) rotates, the displacing sections (15) are repeatedly displaced in the radial direction. By the displacement of the displacing sections (15), wave motion is generated in an external gear (4). It is possible to achieve a wave generator capable of generating wave motion in the external gear (4) with a small rotational torque.