Harmonic Speed Reducer Bearing Length for Stable Gear Meshing
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Solution Overview
Problem
Traditional harmonic gear reducers face issues with incomplete axial expansion and uneven radial deformation of flexible bearings, leading to insufficient meshing contact, transmission errors, and reduced service life due to their short axial length.
Innovation Solution
The design includes a flexible bearing with a longer length than the outer wheel tooth set, ensuring full expansion and uniform deformation of the peripheral wall, which enhances the coaxiality and meshing contact between the outer and inner wheel tooth sets, reducing transmission errors and extending the service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the axial length of the flexible bearing is reduced to meet lightweight requirements, then the weight of the speed reducer is reduced, but the expansion and deformation of the peripheral wall along the axial direction becomes incomplete, resulting in insufficient meshing contact and transmission errors
Solution Approach 1:
The patent optimizes the axial length parameter of the flexible bearing to a specific range (0.3-0.7 times the axial length of the peripheral wall) to achieve the best balance between weight reduction and meshing contact quality. This parameter optimization ensures complete expansion and deformation of the peripheral wall while maintaining lightweight design.
Solution Approach 2:
The flexible bearing's axial length is designed to slightly exceed the minimum required length (being greater than the tooth root length of the outer wheel tooth set), ensuring that the expansion and deformation of the peripheral wall is complete and uniform, thereby guaranteeing sufficient meshing contact between gear teeth.
2Device complexity
If the axial length of the flexible bearing is reduced, then the device complexity is reduced, but the installation coaxiality between the flexible bearing and the flexible wheel becomes difficult to ensure, resulting in uneven radial deformation and unstable stress state
Solution Approach 1:
The patent specifies that the axial length of the flexible bearing should be within a particular range (0.3-0.7 times the axial length of the peripheral wall) to ensure proper installation coaxiality and stable stress distribution. This parameter control prevents uneven radial deformation and maintains structural stability.
Solution Approach 2:
The flexible bearing is designed with sufficient axial length to ensure stable stress state and uniform deformation, which extends its service life and reliability, replacing the need for frequent maintenance or replacement that would result from premature failure.
3Volume of moving object
If the axial length of the flexible bearing is reduced, then the size of the speed reducer is reduced, but the service life of the flexible bearing is shortened due to unstable stress state and insufficient meshing contact
Solution Approach 1:
The patent determines the optimal axial length of the flexible bearing (within 0.3-0.7 times the axial length of the peripheral wall) to ensure uniform stress distribution and complete meshing contact, thereby maximizing the service life while maintaining compact size.
Solution Approach 2:
The flexible bearing is designed with axial length greater than the tooth root length of the outer wheel tooth set, ensuring that the bearing fully engages with the gear teeth and maintains stable stress state throughout its operational life, thus extending service life.
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 effectively reduces transmission errors and prolongs the service life of the flexible bearing by ensuring sufficient meshing contact and uniform deformation, leading to more stable and accurate operation.
Implementation Method 1
The cam is inserted into the flexible bearing, such that the flexible bearing deforms and has an oval outer surface
Implementation Method 2
the expansion and deformation of the peripheral wall along the radial direction are uneven
Implementation Method 3
the expansion and deformation of the peripheral wall along the axial direction will be incomplete
Data Source
AI summary
A speed reducer and a robot are disclosed. The speed reducer includes a rigid wheel, a flexible wheel and a flexible bearing; the rigid wheel is provided with a first fitting position and an inner wheel tooth set; the outer peripheral surface of a peripheral wall of the flexible wheel is provided with an outer wheel tooth set; in the axial direction of the rigid wheel, the tooth top of the outer wheel tooth set is provided with a first length, and the tooth root of the outer wheel tooth set is provided with a second length; the tooth top of the inner wheel tooth set is provided with a third length; the flexible bearing is provided with a fourth length; the second length and the third length are both greater than the first length, and the fourth length is greater than the second length.