Low-Floor Bus Support Structure for Rear-Drive Accessibility
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Solution Overview
Problem
Converting a rear-wheel-drive truck into a low-floor bus is challenging due to the need for significant structural modifications to maintain a low floor height while ensuring adequate ground clearance and traction, especially for wheelchair accessibility and safety standards.
Innovation Solution
A support structure for a low-floor bus with a front transfer case and rear manifold, accommodating a second drive shaft to connect with the differential, allowing for a retractable ramp and beam configurations that maintain ground clearance and support the drivetrain, enabling easy boarding and disembarking for wheelchair users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rear-wheel-drive truck chassis is converted into a low-floor bus, then superior pavement traction and power distribution are achieved, but significant structural modifications to the chassis, drivetrain, and suspension are required
Solution Approach 1:
The drivetrain system is segmented into multiple components: a first transfer case positioned forward to receive power from the transmission, a second transfer case positioned rearward to drive the rear wheels, and drive shafts connecting these components. This segmentation allows each component to be independently positioned and sized, reducing the need for extensive chassis modifications while maintaining superior rear-wheel-drive traction characteristics
Solution Approach 2:
The patent introduces a longitudinal dimension to the drivetrain configuration by positioning transfer cases at different locations along the vehicle length (first transfer case forward, second transfer case rearward). This dimensional arrangement allows power to be transmitted to rear wheels without requiring the entire drivetrain to be compact, thereby reducing structural modification requirements while maintaining traction performance
2Ease of operation
If the floor is disposed at low height for wheelchair accessibility, then ease of use by wheelchair users is improved, but adequate ground clearance becomes difficult to maintain
Solution Approach 1:
The floor support structure is segmented into multiple support elements (beams, crossmembers, and transfer cases positioned at different heights and locations). This segmentation allows the floor to be supported at low height for wheelchair accessibility while the drivetrain components are positioned in the space below, maintaining adequate ground clearance without compromising either accessibility or clearance requirements
Solution Approach 2:
The patent utilizes the vertical and longitudinal dimensions efficiently by positioning drivetrain components (transfer cases, drive shafts) in the space beneath the low floor. This three-dimensional arrangement allows the floor to be lowered for accessibility while drivetrain components occupy the available space below, maintaining ground clearance without interfering with wheelchair access
3Adaptability or versatility
If a first transfer case is disposed on the front end of the floor support structure to receive drive shafts, then adaptability for rear-wheel-drive vehicles is improved, but device complexity increases
Solution Approach 1:
The first transfer case positioned on the front end of the floor support structure serves multiple functions: it receives power from the transmission via the first drive shaft, transmits power through the second drive shaft to the second transfer case, and enables adaptation to rear-wheel-drive vehicle configurations. This multi-functionality reduces the need for additional specialized components, thereby improving adaptability while limiting the increase in overall device complexity
Data Source
AI summary
A support structure for a low-floor bus having front wheels and rear wheels, the support structure including a floor support structure having a front end and a read end, wherein the floor support structure is configured to receive front side rails on the front end of the floor support structure and rear side rails on the rear end of the floor support structure, and a first transfer case disposed on the front end of the floor support structure, wherein the first transfer case is configured to receive a first drive shaft from the low-floor bus on a first end of the first transfer case and to receive a second drive shaft on a rear end of the first transfer case, the second drive shaft is configured to drive the rear wheels.