Bicycle Rear Wheel Height Adjustment for Rollover Prevention
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Solution Overview
Problem
Bicycles face safety issues due to rollover accidents when the front wheel is braked on a downhill road or the center of gravity shifts rearward on an uphill road, leading to reduced grip force and potential wheel lift.
Innovation Solution
A wheel height adjustment structure that includes a rotatable hanger with a dropout, adjustable via a lever or hydraulic cylinder, allowing for the rear wheel height to be adjusted based on riding conditions to prevent rollover and wheel lift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rear wheel height is fixed, then the bicycle structure is simple, but the bicycle cannot prevent rollover accidents on downhill roads or wheel lift on uphill roads
Solution Approach 1:
The hanger is made rotatable relative to the frame through a hinge, allowing the rear wheel height to be dynamically adjusted based on riding conditions. The adjusting portion (lever or hydraulic cylinder) enables the hanger to rotate between a first position for downhill/flat road braking safety and a second position for uphill road stability, transforming a static structure into a dynamic one that adapts to different gravitational forces and center of gravity positions.
2Device complexity
If a lever mechanism is used for adjustment, then the device is simple, but the adjustment precision and stability are limited
Solution Approach 1:
The hydraulic cylinder is connected between the frame and the hanger, using hydraulic pressure to precisely control the rotation angle of the hanger. When the rider operates the lever, hydraulic fluid is pressurized and transmitted to the cylinder, which then moves the hanger to the predetermined angle for optimal rear wheel height, providing more precise and stable adjustment compared to a simple lever mechanism.
3Reliability
If the hanger is made rotatable to adjust wheel height, then safety is improved, but the device complexity increases
Solution Approach 1:
The elastic member (spring) is connected between the hanger and the frame, providing a restoring force that automatically returns the hanger to its original position after adjustment. This counteracts the gravitational force and maintains the hanger in the adjusted position, reducing the need for complex locking mechanisms and simplifying the overall structure while maintaining safety improvements.
4Stability of the object's composition
If the center of gravity shifts rearward on uphill roads, then the bicycle can maintain stability, but the front wheel lifts from the ground reducing grip force
Solution Approach 1:
The system dynamically adjusts the rear wheel height by rotating the hanger to a second position when uphill riding is detected, raising the rear wheel to compensate for the rearward shift in center of gravity. This maintains the bicycle's stability while preventing excessive front wheel lift, thereby preserving front wheel grip force on the ground.
5Speed
If the front wheel is braked on downhill roads, then the bicycle can slow down, but the bicycle may roll over due to nose-down
Solution Approach 1:
When downhill braking is required, the hanger rotates to the first position, lowering the rear wheel height. This shifts the center of gravity forward, counteracting the nose-down effect caused by front wheel braking, thereby preventing rollover accidents while maintaining effective speed control.
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
The system effectively prevents rollover accidents by adjusting the rear wheel height in response to braking on downhill roads and shifting center of gravity on uphill roads, enhancing safety and stability.
Implementation Method 1
an elastic member that elastically supports the hanger such that the hanger rotates back to its original location with respect to the hinge
Implementation Method 2
a hydraulic cylinder that is provided to rotate the hanger by using a hydraulic pressure that is supplied according to operation of the lever
Data Source
AI summary
A bicycle having a wheel height adjustment structure according to an exemplary embodiment of the present invention includes: a bicycle frame; a hanger where a dropout is formed and rotatably coupled to one side of the frame with respect to a hinge; and an adjusting portion that adjusts a height of the wheel that is engaged to the dropout by rotating the hanger at a predetermined angle.