ATV Rear Drive Offset Sprocket and Dual Joint Suspension
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Solution Overview
Problem
Conventional all-terrain vehicles (ATVs) face a trade-off between being lightweight, powerful, and durable while maintaining high-quality ride characteristics, often resulting in added weight and compromised performance.
Innovation Solution
An external chain-driven ATV with an independent rear suspension system and a rear drive mechanism featuring a drive sprocket offset from the centerline, utilizing dual offset joints for extended half shafts to enhance power transfer efficiency and ride quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional swing arm rear suspension is used, then the ATV achieves basic ride characteristics, but the vehicle weight increases and ride quality deteriorates
Solution Approach 1:
The rear suspension system is divided into independent left and right sides, with each side having its own control arm, shock absorber, and drive mechanism. This independent segmentation allows each wheel to move independently, improving ride quality while using lightweight individual components rather than a heavy interconnected swing arm system
Solution Approach 2:
The control arms are designed to dynamically adjust their position and orientation as the wheels move through their suspension travel. The dual offset joints allow the half shafts to maintain proper alignment dynamically during suspension movement, ensuring consistent power transfer and ride characteristics throughout the range of motion
2Loss of energy
If the drive sprocket is positioned on the centerline, then the drive mechanism is simplified, but the chain length increases and power transfer efficiency decreases
Solution Approach 1:
The drive sprocket is deliberately positioned offset from the centerline of the ATV, creating an asymmetric drive layout. This offset positioning reduces the chain length and improves power transfer efficiency, while the complexity is managed through the dual offset joint design that accommodates the asymmetric configuration
Solution Approach 2:
The dual offset joint acts as an intermediary mechanism between the offset drive sprocket and the wheels. It mediates the asymmetric power transfer by accommodating both the offset from the ATV centerline and the offset from the wheel centerline, enabling efficient power delivery without requiring a complex universal joint arrangement
3Reliability
If extended length half shafts are used, then the independent rear suspension travel is improved, but the risk of shaft failure and power transfer loss increases
Solution Approach 1:
The dual offset joints are designed to dynamically maintain proper half shaft alignment throughout the suspension travel range. By keeping the half shafts properly aligned with the drive sprocket and wheel centers during movement, the system reduces bending moments and stress concentrations, allowing extended length shafts to maintain strength and durability
Solution Approach 2:
The control arm geometry and dual offset joint positioning are designed in advance to prevent excessive angles and misalignment during suspension travel. This proactive design cushions the half shafts against extreme stress conditions that would otherwise lead to failure, enabling the use of lighter, extended length shafts
Data Source
AI summary
A vehicle, including an independent rear suspension and a rear drive mechanism including a pair of dual offset joints mounted in a sprocket hub. Each dual offset joint is connected to a half shaft coupled to a wheel. A driven sprocket is connected to the sprocket hub at a location offset from a centerline of the vehicle. An external chain coupled to a drive sprocket coupled to the vehicle's engine and the driven sprocket to transfer rotational movement of the drive sprocket to the driven sprocket, thereby causing rotation of the sprocket hub, the dual offset joints, the half shafts, and the wheels.