Concentric Swingarm Motor Layout for Constant Chain Tension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motorcycles with swingarm rear suspension and electric drive motors face challenges in maintaining optimal drivetrain tension and durability due to variations in suspension travel, which affect the center distance between the drive and driven sprockets, leading to inefficiencies and reduced durability.
Innovation Solution
The integration of an electric motor with a co-axial output shaft and swingarm pivot axis, where the motor case acts as a stressed frame member, supports the swingarm and rear wheel, eliminating the need for a separate pivot shaft and maintaining consistent tension in the endless drive member throughout suspension travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the motor case is used as a stressed frame member to support the swingarm, then the device complexity is reduced and manufacturing cost is lowered, but the structural integrity and reliability may be compromised
Solution Approach 1:
The motor case is merged with the frame structure, serving dual functions as both the motor housing and a stressed frame member that supports the swingarm. This integration eliminates the need for separate frame members, reducing device complexity while maintaining structural integrity through the co-axial alignment of the motor output shaft with the swingarm pivot axis.
2Reliability
If the swingarm pivot axis is co-axial with the motor output shaft axis, then the drivetrain tension consistency is improved and durability is enhanced, but the design flexibility and adaptability are reduced
Solution Approach 1:
The swingarm pivot axis is aligned co-axially with the motor output shaft axis, creating an equipotential configuration where the center distance between drive and driven sprockets remains constant throughout suspension travel. This alignment eliminates variations in drivetrain tension, improving reliability while the modular motor-case-frame integration maintains design flexibility for different motorcycle configurations.
Data Source
AI summary
A motorcycle includes an electric motor having an output shaft defining a motor axis, a rear wheel drivably coupled to the electric motor to propel the motorcycle, a swingarm rotatably supporting the rear wheel, and a frame. The frame includes a main frame member supporting the electric motor and the swingarm. A case of the electric motor is a stressed member of the frame between the main frame member and the swingarm. The swingarm is coupled to the case of the electric motor to define a swingarm pivot axis that is co-axial with the motor axis.