Strain Wave Gear Sliding Bearing for Compact Load Support
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Solution Overview
Problem
Unit-type strain wave gearings with rolling bearings are limited in compactness and ease of gap adjustment, as radial sliding bearings lack a gap-adjustment mechanism, making them less efficient and more complex to manufacture.
Innovation Solution
The use of a sliding bearing with inclined surfaces allows for relative rotation between a rigid internally toothed gear and a flexible externally toothed gear, facilitating gap adjustment and reducing the device's size by eliminating the need for radial sliding bearings, while using self-lubricating materials and surface treatments for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial sliding bearing is used to support the internally toothed gear and externally toothed gear, then the bearing can handle radial loads, but the gap adjustment becomes difficult and manufacturing precision requirements increase
Solution Approach 1:
The bearing surface is designed with an inclination angle relative to the center axis, transforming the static bearing surface into a dynamic configuration that automatically accommodates radial loads while providing inherent gap adjustment capability through the inclined geometry
Solution Approach 2:
The inclination angle of the bearing surface is optimized to balance between radial load bearing capacity and gap adjustment ease, allowing the same bearing structure to perform both functions effectively without requiring separate adjustment mechanisms
2Reliability
If rolling bearings are used in unit-type strain wave gearing, then the gearing can support radial and thrust loads, but the device size increases and compactness is reduced
Solution Approach 1:
The sliding bearing integrates both radial and thrust load bearing functions into a single component structure, eliminating the need for separate radial and thrust bearings that would be required in rolling bearing configurations, thereby reducing overall device volume
Solution Approach 2:
The inclined sliding bearing surface serves multiple functions simultaneously: supporting radial loads, supporting thrust loads, and providing gap adjustment capability, making the bearing structure more versatile and compact compared to traditional rolling bearing arrangements
3Ease of operation
If the sliding bearing surface is inclined relative to the center axis, then gap adjustment is facilitated and radial sliding bearing is obviated, but the bearing must simultaneously handle both radial and thrust loads
Solution Approach 1:
The inclined bearing surface creates a dynamic load distribution mechanism where radial and thrust loads are automatically resolved into components along the inclined surface, simplifying the bearing configuration while maintaining load bearing capability
Solution Approach 2:
The inclination angle parameter is optimized to simultaneously satisfy gap adjustment requirements and load bearing requirements, transforming a potentially complex multi-bearing configuration into a simpler single-bearing solution
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 configuration results in a lightweight, compact unit-type strain wave gearing capable of efficiently bearing both radial and thrust loads, with improved manufacturing precision and reduced component count, enabling easier gap adjustment and enhanced wear resistance.
Implementation Method 1
a sliding bearing provided with a fixed-side sliding bearing surface formed on the fixed-side member and a rotating-side sliding bearing surface formed on the rotating-side member and slidably contacting the fixed-side sliding bearing surface
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4
AI summary
In a unit-type strain wave gearing (1), a rotating-side member (B), which is constituted by a second internally toothed gear (4) and an output shaft (5), is supported, via a first sliding bearing (8) and a second sliding bearing (9), on a fixed-side member (A) so as to be capable of relative rotation, the fixed-side member being constituted by a unit housing (2) and a first internally toothed gear (3). Sliding bearing surfaces (8b, 8c) of the first sliding bearing (8) and sliding bearing surfaces (9b, 9c) of the second sliding bearing (9) are defined by a conic surface having a central axis line (1a) as a center line. It is possible to realize a unit-type strain wave gearing which is advantageous in making smaller and more compact than when a roller bearing is used. It is also easier to adjust the gap between the sliding bearing surfaces because a radial sliding bearing having no function to adjust the radial gap is obviated.