Bicycle Drive Unit Layout for Compact Side-by-Side Motor Battery Packaging
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Solution Overview
Problem
Existing bicycle components with propulsion assist motors face challenges in reducing the size of the motor housing in a direction parallel to the crankshaft's rotational axis, making it difficult to minimize the overall component size effectively.
Innovation Solution
The design incorporates a propulsion assist motor with a rotational axis intersecting the crankshaft's axis, allowing the motor and battery to be accommodated within the bicycle frame, with the motor and battery arranged next to each other and detachably coupled, reducing the motor's size in the sideward direction and optimizing the use of the frame's interior for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rotational axis of the propulsion assist motor is arranged parallel to the rotational axis of the crankshaft, then the motor can be easily integrated with the crankshaft, but the size of the bicycle component in the direction parallel to the crankshaft's rotational axis cannot be reduced
Solution Approach 1:
The patent changes the spatial arrangement by orienting the motor's rotational axis perpendicular to the crankshaft's rotational axis. This dimensional reorientation allows the motor housing to extend in a direction orthogonal to the crankshaft axis, thereby reducing the component's footprint in the axial direction while maintaining effective integration with the crankshaft through the bottom bracket assembly.
2Volume of moving object
If the second portion and battery are arranged next to each other and accommodated in the frame, then the overall bicycle size is reduced, but the attachment and detachment operations become more complex
Solution Approach 1:
The housing is divided into a first portion and a second portion that can be detachably connected. The battery can be attached to either the first or second portion, creating modular sub-assemblies. This segmentation allows the battery and motor components to be separately attached and detached, simplifying maintenance and battery replacement while maintaining a compact overall configuration when assembled.
Solution Approach 2:
The patent implements attachable and detachable connections between the battery and housing portions, and between the housing and frame. This dynamic configuration allows users to attach or detach the battery as needed, providing flexibility for maintenance, charging, or replacement without requiring complex disassembly of the entire drive unit, thus balancing compactness with operational ease.
3Shape
If the motor housing size is reduced in the sideward direction, then the bicycle appearance and frame integration are improved, but the motor's torque output capability may be compromised
Solution Approach 1:
The motor housing is designed to extend primarily in the direction orthogonal to the crankshaft's rotational axis rather than parallel to it. This dimensional reorientation allows the housing to achieve an elongated shape perpendicular to the crankshaft, providing sufficient internal volume for the motor windings and magnetic components to generate adequate torque, while keeping the axial footprint compact for better frame integration and appearance.
Solution Approach 2:
The patent changes the geometric parameters of the motor housing by orienting it perpendicular to the crankshaft axis. This parameter change in spatial orientation allows the motor to maintain its torque-generating dimensions in the radial direction while minimizing its axial projection, thereby preserving torque output capability while achieving a more compact and aesthetically pleasing integration with the bicycle frame.
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 enables a significant reduction in the size of the bicycle component, enhancing the integrity and appearance of the drive unit while maintaining sufficient strength and propulsion assistance, as the motor's output is maintained within optimal torque and power ranges.
Implementation Method 1
a propulsion assist motor provided to a second portion of the housing... The battery is electrical connected to the propulsion assist motor to supply electrical power to the propulsion assist motor
Data Source
AI summary
A bicycle component includes a drive unit and a battery. The drive unit includes a housing mounted on a bicycle frame, a crankshaft provided to a first portion of the housing, and a propulsion assist motor provided to a second portion of the housing. The battery is electrical connected to the propulsion assist motor to supply electrical power to the propulsion assist motor. The propulsion assist motor includes a rotational axis extending in a direction intersecting a direction in which the crankshaft extends. At least part of the second portion and at least part of the battery are accommodated in the frame in a state in which the second portion and the battery are arranged next to each other in a direction parallel to the rotational axis of the propulsion assist motor and the battery is coupled to the second portion in an attachable and detachable manner.