Integrated Sun-Ratchet Gear for Power-Assisted Bicycle Noise Reduction
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Solution Overview
Problem
Conventional centrally-positioned power output mechanisms in power-assisted bicycles are prone to noise and vibration due to processing errors, and their bulky design increases space occupation and delivery costs.
Innovation Solution
A compact power output mechanism integrating a ratchet and helical gear as the sun gear, along with a transmission unit comprising a ring gear, planetary carrier, and planetary gears, which reduces noise and vibration by enhancing power transmission efficiency and eliminating processing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional separately-arranged gears are used to eliminate processing errors, then noise and vibration are reduced, but device complexity and space occupation increase
Solution Approach 1:
The patent combines the sun gear and ratchet into a single integrated component called a 'sun-ratchet integrated gear'. This merging eliminates the need for separate helical gears and reduces the number of parts, thereby reducing device complexity while maintaining the noise and vibration reduction benefits through precise meshing geometry
2Object-generated harmful factors
If conventional separately-arranged gears are used to eliminate processing errors, then noise and vibration are reduced, but the space occupied and delivery cost increase
Solution Approach 1:
By integrating the sun gear and ratchet into one component, the patent reduces the overall volume occupied by the transmission mechanism. The combined sun-ratchet integrated gear occupies less space than multiple separate gears would require, thereby reducing both space occupation and delivery cost while eliminating noise and vibration
Solution Approach 2:
The planetary gears are arranged around the central sun-ratchet integrated gear in a nested configuration, allowing compact packaging of multiple gear components in a centralized arrangement that minimizes the overall volume of the transmission mechanism
3Manufacturing precision
If multiple separately-arranged gears are used, then processing errors are eliminated, but the number of parts and assembly complexity increase
Solution Approach 1:
The patent integrates the sun gear and ratchet into a single sun-ratchet integrated gear component. This merging reduces the number of parts that need to be manufactured and assembled, thereby reducing device complexity and assembly complexity while maintaining processing precision through the integrated design
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
The integrated ratchet and helical gear design improves compactness, reduces noise and vibration, and enhances the durability and stability of the power output mechanism, providing a smoother operation with high torque output.
Implementation Method 1
The transmission unit is disposed inside the housing and has a sun gear, a planetary carrier, and at least two planetary gears. The sun gear is sleeved onto the crankshaft and has a helical gear and a ratchet.
Implementation Method 2
The planetary gears are disposed at the planetary carrier and each has a helical tooth portion and a planetary tooth portion. The helical tooth portion is engaged with the helical gear of the sun gear.
Data Source
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AI summary
A centrally-positioned power output mechanism (10) of a power-assisted bicycle includes a housing (20), a crankshaft (30) inserted through the housing (20), a large sprocket (40) connected to the crankshaft (30), a motor (50) disposed at the crankshaft (30), and a transmission unit (60). The transmission unit (60) has a sun gear (62), a ring gear (61) fixed to the housing (20) and disposed therein, a planetary carrier (63) connected to the large sprocket (40), and two planetary gears (64) disposed at the planetary carrier (63). The sun gear (62) has a helical gear (70) and a ratchet (80) connected to the helical gear (70) and the motor (50). The planetary gears (64) each has a helical tooth portion (642) engaged with the helical gear (70) and a planetary tooth portion (644) is engaged with the ring gear (61). The helical gear (70) of the sun gear (62) is engaged with the helical tooth portions (642) of the planetary gears (64) to thereby enhance compactness, eliminate processing errors, and reduce noise and vibration during operation.