Planet Roller Speed Changer Bushing Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional planet roller speed changers experience significant rotational fluctuations due to misalignment of the center of rotation of the carrier with the center of revolutions of the planet rollers, leading to advanced or delayed rotation of the carrier, especially when mounted transversely in apparatuses like image forming devices.
Innovation Solution
The planet roller speed changer is designed with a specific configuration where the pitch circle diameter of the carrier is set to be larger than the value obtained by doubling the inter-axis distance between the input shaft and planet rollers, and bushings with unique geometries are used to manage clearances and frictional forces, promoting alignment and reducing rotational fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planet rollers are supported in a loosely fitted state by pins to allow carrier displacement, then ease of assembly and tolerance compensation are improved, but rotational fluctuations increase due to misalignment between carrier rotation center and planet roller revolution center
Solution Approach 1:
A bushing is introduced as an intermediary component between the pin and the planet roller. The bushing has a specific geometry where its outer peripheral face forms a contact surface with the inner periphery of the planet roller. This intermediary element mediates the interaction between the pin and planet roller, allowing the bushing to contact the planet roller at a controlled location that helps maintain alignment between the carrier rotation center and planet roller revolution center, thereby reducing rotational fluctuations while preserving the loosely fitted support structure
Solution Approach 2:
The pitch circle diameter of the carrier is specifically designed to be larger than the value obtained by doubling the inter-axis distance between the input shaft and planet rollers. This parameter change creates a geometric relationship that compensates for misalignment effects. Additionally, the bushing geometry is specifically designed with its outer peripheral face positioned at a predetermined location to optimize the contact point and minimize rotational fluctuations
2Measurement precision
If the pitch circle diameter of the carrier is increased to compensate for misalignment, then rotation accuracy is improved, but the overall device size increases
Solution Approach 1:
The pitch circle diameter of the carrier is specifically designed to be larger than the value obtained by doubling the inter-axis distance between the input shaft and planet rollers. This parameter change creates a geometric relationship that compensates for misalignment effects. Additionally, the bushing geometry is specifically designed with its outer peripheral face positioned at a predetermined location to optimize the contact point and minimize rotational fluctuations
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 restricts rotational fluctuations even when misalignment occurs, ensuring a high degree of rotation accuracy and stability in the planet roller speed changer.
Implementation Method 1
When the outer peripheral face of the bushing contacts the input shaft side-portion of the inner periphery of the planet roller, the revolution of the pin may be promoted
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a planet roller speed changer, a plurality of shaft portions of a carrier is disposed such that, when the carrier is displaced in a direction that intersects with the axial direction of an output shaft, the outer periphery of at least one of the shaft portions that are displaced with a displacement of the carrier contacts the stationary ring-side portion of the inner periphery of a corresponding planet roller without contacting the input shaft-side portion of the inner periphery of the corresponding planet roller.