Planetary Roller Bearing Gap Elimination
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Solution Overview
Problem
Conventional planetary rolling rotation transmitting devices suffer from non-uniform rotation due to gaps in bearings and reduced rigidity, leading to inaccuracies in rotation transmission.
Innovation Solution
The use of tapered or angular bearings with an elastic ring and solid cylindrical components to eliminate gaps and improve rigidity, ensuring uniform contact pressure and reduced wobbling, thereby stabilizing the rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ball bearings or needle bearings are used in planetary rollers, then the planetary roller can rotate smoothly, but gaps between bearing components cause non-uniform rotation
Solution Approach 1:
The patent removes the traditional bearing components (inner race, outer race, rolling elements) from the planetary roller structure. Instead of using conventional bearings, the invention employs a solid cylindrical planetary roller body with integrated rolling surfaces that directly contact the sun gear and planetary gear, eliminating the bearing gaps that cause non-uniform rotation while maintaining smooth rotation capability
Solution Approach 2:
The patent integrates the bearing functions directly into the planetary roller structure itself. The planetary roller is designed as a solid cylindrical body where the rolling contact surfaces are formed directly on the roller body, merging the structural support function and the bearing function into a single integrated component, thereby eliminating gaps between separate bearing components
2Ease of manufacture
If a hollow cylindrical body is used as the planetary roller main body to accommodate bearings, then bearings can be installed, but the rigidity of the planetary roller decreases
Solution Approach 1:
The patent extracts and removes the separate bearing components from the planetary roller structure. The planetary roller is designed as a solid cylindrical body without internal hollow spaces for bearing accommodation, eliminating the need for complex bearing installation while maintaining high rigidity through the solid structure
Solution Approach 2:
The patent merges the bearing support function into the solid cylindrical structure of the planetary roller itself. The rolling contact surfaces are directly formed on the solid roller body, combining the structural integrity of a solid cylinder with the bearing function, thereby achieving both ease of manufacture and high rigidity
3Device complexity
If the support shaft is used in a cantilever manner to support the planetary roller, then the structure is simple, but the support shaft bends under contact pressure causing the planetary roller to lean
Solution Approach 1:
The patent removes the separate support shaft structure from the planetary roller assembly. The planetary roller is directly supported by the planetary gear mechanism itself through the solid cylindrical structure, eliminating the support shaft and its associated bending and leaning problems while maintaining structural simplicity
Solution Approach 2:
The patent merges the support function into the planetary gear mechanism structure. The solid cylindrical planetary roller is directly supported by the planetary gear through rolling contact, combining the support function with the gear mechanism itself, thereby eliminating the need for separate support shafts and ensuring uniform contact surfaces
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 restrains non-uniform rotation by eliminating bearing gaps and enhancing the rigidity of planetary rollers, ensuring high precision and accuracy in rotation transmission.
Implementation Method 1
an elastic ring 81 which is covered with the planetary rollers 41 from the outside, where the planetary rollers 41 roll on an inner circumferential surface while being imparted the contact pressure by forcing the planetary rollers 41 against the sun shaft 21
Implementation Method 2
each of the rolling elements being limited by the inner race from moving inward in a radial direction and moving toward one direction along the rotation axis, as well as being limited by the outer race from moving outward in the radial direction and moving toward a direction opposite the one direction in the direction along the rotation axis
Implementation Method 3
a plurality of push-in members each sandwiching, in the direction along the rotation axis, with a predetermined portion of the planetary carrier a pair of the bearings to force the outer race toward the inner race
Implementation Method 4
a plurality of planetary rollers 41 that are pressed with a predetermined contact pressure against an outer circumferential surface of the sun shaft 21 while rolling on the outer circumferential surface thereof to revolve around the sun shaft 21 while spinning
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A planetary roller 41 includes a cylindrical rolling portion 41a that rolls on an outer circumferential surface of the sun shaft 21 and a pair of shafts 41b, 41b integrally formed with the cylindrical rolling portion 41a to protrude from both ends thereof in a rotation axis C41 direction to support the cylindrical rolling portion 41a at both ends via bearings 31. The bearing 31 is a tapered roller bearing or an angular bearing including an inner race 31a fit to the shaft 41b, an outer race 31b attached to a planetary carrier 61, and a rolling element 31c that rolls between these races 31a, 31b. The rolling element 31c is limited by the inner race 31a from moving inward in a radial direction and in one direction in the rotation axis direction C41 and limited by the outer race 31b from moving outward in the radial direction and in a direction, opposite the above one direction, in the rotation axis C41 direction. In a state where the bearings 31, 31 are attached to correspond to the pair of shafts 41b, 41b, a push-in member 67 is screwed to the planetary carrier 61 for sandwiching with a predetermined portion 63a of the planetary carrier 61 the pair of bearings 31, 31 in the rotation axis C41 direction to force the outer race 31b toward the inner race 31a.