Hub Motor Transmission Using Centrifugal Speed-Based Gear Shifting
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Solution Overview
Problem
Existing hub motors with integrated transmission mechanisms experience frequent gear shifting at high speeds, affecting riding experience and reducing the service life due to automatic downshifts when pedal frequency decreases.
Innovation Solution
A hub motor with an integrated transmission mechanism that shifts gears based on output speed rather than pedal frequency, using a centrifugal drive assembly with a single elastic reset member to ensure smooth gear transitions and reduce shifting frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If gear shifting is controlled by pedal frequency, then automatic transmission can be achieved, but gear shifting frequency increases at high speeds affecting service life
Solution Approach 1:
The patent changes the control parameter from pedal frequency to output speed. The centrifugal block responds to output speed directly, maintaining high gear state when output speed is high regardless of pedal frequency, thereby reducing unnecessary gear shifts and improving reliability while preserving automatic transmission functionality
2Ease of operation
If multiple elastic reset members are used, then gear shifting can be facilitated, but inconsistent reset performance occurs due to material variations
Solution Approach 1:
The patent extracts the elastic reset member from the system, replacing it with a limit plate structure that provides mechanical resetting. This eliminates the variability introduced by elastic material properties while maintaining the necessary gear shifting functionality through pure mechanical means
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
Reduces gear shifting frequency and prolongs the service life of the transmission mechanism by maintaining high gear state during downhill riding without pedal input, enhancing the overall riding experience.
Implementation Method 1
a centrifugal block is swung out to achieve automatic up shift when a certain pedal frequency is reached
Implementation Method 2
an elastic reset member connected to only one centrifugal block of the centrifugal drive assembly, the other end of the shaft rod is connected to the limit plate in a rotating connection manner, and the other end of the limit plate is connected to the positioning plate
Data Source
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AI summary
Provided is a hub motor which has an integrated transmission mechanism, comprising a main shaft (1). A hub (21) and an end cover (22) which are connected to each other are provided on the main shaft (1). A machine core assembly connected to the hub (21) and a transmission mechanism connected to the end cover (22) are each disposed on the main shaft (1).The transmission mechanism comprises a centrifugal drive assembly. The centrifugal drive assembly is connected to the end cover (22) and switches states according to the rotation speed of the end cover (22).