Eccentric Gearbox Drive Assembly for Compact Pedal-Generator Conversion
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Solution Overview
Problem
Existing muscle-powered vehicles, such as electric bicycles, face challenges in achieving a compact and efficient drive arrangement that eliminates mechanical connections between the pedal crank and the rear wheel while optimizing torque and rotational speed conversion.
Innovation Solution
A drive arrangement utilizing an eccentric transmission with a generator module that includes a gearbox to increase rotational speed and reduce torque, featuring a compact design with an eccentric gear system that integrates a roller carrier, cam disks, and a ring gear section to transmit pedaling force to a generator, eliminating the need for self-locking mechanisms and allowing for a continuous shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional gear types (planetary gears, Wolfrom sets) are used to increase crankshaft speed and reduce torque, then the generator size can be reduced, but the device complexity and space requirements increase
Solution Approach 1:
The patent changes the fundamental parameters of the gear system by using an eccentric gear mechanism instead of conventional planetary gears. This eccentric design with offset center achieves the required speed increase and torque reduction while simplifying the overall structure and reducing the number of components needed, thereby decreasing device complexity while maintaining compact generator size
2Device complexity
If conventional gear types are used to eliminate mechanical connections, then the drive arrangement can be simplified, but the space requirements and device complexity increase
Solution Approach 1:
The eccentric gear mechanism is designed to be nested within the generator housing, with the eccentric shaft and gear components arranged concentrically. This nesting approach allows the drive assembly to occupy minimal space while maintaining mechanical simplicity, as the eccentric gear components are integrated within the existing generator structure rather than requiring additional external space
3Productivity
If high pedaling torque is converted to lower torque at higher speeds, then the generator can operate more efficiently, but friction losses may increase
Solution Approach 1:
The patent extracts and eliminates self-locking mechanisms from the drive system, using only the essential eccentric gear components for torque conversion. This reduction in components minimizes the number of friction interfaces while maintaining the necessary torque-speed conversion, thereby reducing overall friction losses while preserving generator operating efficiency
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 eccentric gear system provides a quiet, efficient, and compact drive solution that effectively converts high pedaling torque into lower torque at higher speeds, reducing development costs and space requirements, while enabling the use of standard crank arms and reducing friction losses.
Implementation Method 1
The transmission unit (16) is designed as an eccentric gear (20). The eccentric gear (20) has a roller carrier (25) as its input element, which is arranged non-rotatably with the pedal crank shaft (14). Furthermore, two cam disks (26, 27) are provided, wherein the cam disks (26, 27) have an eccentric receiving opening (48)
Implementation Method 2
the use of an eccentric gear allows for a particularly quiet transmission with a compact design... the eccentric gear allows for a continuous shaft in the center, which is a fundamental requirement for use in bicycles with crank arms on both sides
Data Source
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AI summary
The invention relates to a drive assembly for a human-powered vehicle which is compact and is characterised by improved efficiency. According to the invention, a drive assembly (5) for a human-powered vehicle (1) is proposed comprising a generator module (6) for generating electrical energy for a drive module (7) for generating an electrical drive torque, the generator module (6) having a generator (15) which can be driven by a vehicle user by pedal force, the generator module (6) having a pedal crankshaft (14) for transmitting the pedal force from a pedal crank (9) to the generator (15), the generator module (6) having a gearbox device (16) for transmitting the pedal force to the generator (15), the pedal crankshaft (14) being connected in gearing terms to the generator (15) via the gearbox device (16), and the gearbox device (15) being designed as an eccentric gearbox (20).