Strain Wave Gear Wave Generator Retainer Integration
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Solution Overview
Problem
In strain wave gearing with roller bearings, there is a lack of equivalent trajectory grooves, necessitating a restricting member to prevent movement of the outer ring and retainer, which complicates the structure and leads to wear due to speed differences.
Innovation Solution
The wave generator features an ellipsoidal roller bearing with an inner ring trajectory surface directly formed on the rigid plug, a retainer engaging part, and an outer ring engaging part, eliminating the need for a separate restricting member by restricting the retainer and outer ring movements through these integrated features, allowing for a larger hollow through-hole without increasing the outside diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a roller bearing is used in the wave generator to reduce radial thickness, then the inside diameter of the hollow part can be increased, but a restricting member such as a thrust washer must be attached to restrict the movement of the outer ring and retainer
Solution Approach 1:
The retainer engaging part is integrated into the plug external peripheral surface, and the outer ring engaging part is integrated into the retainer, merging the restricting function into existing components rather than adding separate restricting members. This reduces device complexity while maintaining the ability to restrict outer ring and retainer movement.
Solution Approach 2:
The restricting function is extracted from separate thrust washers or restricting members and incorporated into the plug and retainer structures themselves. The retainer engaging part and outer ring engaging part are built-in features that perform the restricting function without requiring additional components.
2Reliability
If a restricting member is attached to the rigid plug to restrict outer ring movement, then the outer ring and retainer can be constrained, but the speed difference between the restricting member and outer ring causes wear
Solution Approach 1:
The retainer serves a dual function: it holds the rollers in the roller bearing while simultaneously serving as the restricting member through its outer ring engaging part. Since the retainer rotates at the same speed as the outer ring, there is minimal speed difference between them, significantly reducing wear compared to using a separate restricting member attached to the high-speed rigid plug.
3Reliability
If a separate restricting member is used to constrain the retainer and outer ring, then movement restriction is achieved, but the number of components increases and weight increases
Solution Approach 1:
The restricting function is merged into the existing plug and retainer components. The retainer engaging part is formed as an integral feature of the plug external peripheral surface, and the outer ring engaging part is formed as an integral feature of the retainer. This eliminates the need for separate restricting members, reducing both component count and overall weight.
Data Source
AI summary
A wave generator of a strain wave gearing has a rigid plug and a needle roller bearing mounted on the plug external peripheral surface. The plug external peripheral surface has a retainer engaging part for engaging with a retainer that would move in an axis line direction and for restricting the movement thereof along the axis line direction. The retainer has an outer ring engaging part for engaging with an outer ring that would move in the axis line direction and for restricting the movement thereof along the axis line direction. The movements of the retainer and the outer ring can be restricted without providing a separate member. A wave generator of a strain way gearing can be realized, which is provided with a roller bearing capable of restricting the movement of the outer ring with a simple structure.