Bicycle Drive Unit Rear Wheel Detachment Mechanism
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Solution Overview
Problem
Existing bicycle drive units with integrated electric motors in the rear wheel hub lack simplicity in detachment for maintenance, making inspection and repair cumbersome.
Innovation Solution
A drive unit design where the rear wheel can be easily detached from the rear arm by simplifying the operation, utilizing a radial-gap type electric motor integrated with the rear-wheel hub and a power transmission system that includes a torque sensor and one-way clutch, allowing for efficient power transfer and easy maintenance access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the electric motor is integrated inside the rear-wheel hub, then the power transmission efficiency is improved, but the ease of repair deteriorates
Solution Approach 1:
The drive unit is divided into modular components: the rear-wheel hub containing the electric motor, the rear arm containing the power transmission mechanism, and the connecting structure. This segmentation allows the rear wheel to be detached from the rear arm for maintenance while keeping the motor integrated in the hub, thus maintaining power transmission efficiency while improving ease of repair.
2Stability of the object's composition
If the rear wheel is tightly integrated with the rear arm, then the structural stability is improved, but the ease of operation deteriorates
Solution Approach 1:
The connection between the rear wheel and rear arm is designed to be dynamic rather than fixed. The rear wheel can be easily detached from the rear arm when needed for maintenance or inspection, yet remains securely connected during normal operation. This dynamic connection resolves the contradiction by allowing the system to switch between stable integration and easy operability based on operational needs.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
There is provided a drive unit (10, 110, 210, 310, 410) capable of making a detachment work of the rear wheel (40) from a rear arm (50) easy. An electric wire (64A) structure includes a first electric wire (64A) part extending from an electric motor (30), a second electric wire (64A) part extending along a rear arm (50), and a terminal block (35) for electrically coupling the first electric wire (64A) part and the second electric wire (64A) part to each other. A rear-wheel hub (41) is provided with a support (146, 46) for supporting the rear-wheel hub (41) so as to allow the rear-wheel hub (41) to rotate. The rear arm (50) has a rear case (51) which houses an engaging part between a drive shaft (27) and a transmission shaft (21, 221). The rear case (51) is attached to the support (146, 46) with a screw (35A, 83). The electric wire (64A) structure extends from the rear case (51) toward an inside of the rear-wheel hub (41) passing through an electric wire path (46K, 46M, 51, 53B, 56F) provided to the support (146, 46). The terminal block (35) is located between a left end surface (46N) of the rear case (51) and a right end surface (51) of the rear-wheel hub (41).