Mid-Drive Gearbox With One-Way Bearings for Isolated Power Paths
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Solution Overview
Problem
Existing wheeled vehicles with both pedal and motor assemblies experience undesired interference and frictional losses due to the operation of the motor impacting the pedal assembly, leading to inefficient power delivery.
Innovation Solution
A gearbox with one-way bearings is used to separate and isolate the power paths from the pedal assembly and the motor assembly, allowing independent operation of both systems, enabling simultaneous or independent power delivery from either source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor is used to drive the chain wheel, then power delivery to the driven wheel is achieved, but the motor operation impacts the pedal assembly causing undesired movement
Solution Approach 1:
The power transmission system is divided into two separate one-way bearing paths: one for motor power and one for pedal power. This segmentation allows each power source to operate independently without interfering with the other, resolving the contradiction between motor power delivery and pedal assembly operation.
Solution Approach 2:
One-way bearings act as intermediaries between the motor/pedal assemblies and the chain wheel. These bearings selectively transmit power in the intended direction while blocking reverse power flow, preventing motor operation from impacting the pedal assembly and vice versa.
2Adaptability or versatility
If the motor and pedal assembly share a common power path, then simultaneous operation is possible, but frictional losses increase due to interference between the two systems
Solution Approach 1:
The common power path is segmented into two separate one-way bearing paths that converge at the chain wheel. This allows simultaneous operation of motor and pedal assembly while minimizing frictional losses by preventing interference between the two power sources through directional control.
Solution Approach 2:
The one-way bearings provide dynamic, conditional connectivity: they engage when power needs to be transmitted in the forward direction and disengage when reverse power flow would cause interference. This dynamic behavior reduces frictional losses while maintaining versatility.
Data Source
AI summary
A vehicle may include a pedal assembly, a motor assembly, and a drive unit that may be used to allow selective usage of one or both of the pedal assembly and the motor assembly to convey power to a driven wheel of the vehicle. The drive unit can include a gearbox that may enclose components which form at least part of a first power path between the pedal assembly and the driven wheel and a second power path between the motor assembly and the driven wheel. The first and second power paths can converge at a component within the gearbox. One-way bearings at points in the first and second power paths prior to the convergence of the power paths can inhibit or prevent the pedal assembly from being affected by operation of the motor assembly, and vice versa.