Sidewall Rubber Strip Tyre for Wet E-Bike Roller Drive
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Solution Overview
Problem
Existing wheel drive systems for electric bicycles and wheelchairs face issues with torque transmission in wet weather, rapid wear, and precise roller positioning requirements, which affect durability and grip.
Innovation Solution
A bicycle tire design featuring a rubber strip on the sidewall with specific Shore A hardness and glass transition temperature, allowing smooth contact with a drive roller, ensuring torque transmission without precise alignment and minimizing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a roller with contact on the tread is used to drive the wheel, then torque transmission is achieved, but the tire life is rapidly reduced due to excessive wear on the tread
Solution Approach 1:
The invention separates the driving function from the tread by placing a rubber strip on the sidewall instead of using the tread. The tread maintains its original function of providing grip on the ground, while the sidewall rubber strip serves as the dedicated contact surface for the drive roller, eliminating wear on the tread patterns.
Solution Approach 2:
The invention moves the drive contact from the horizontal tread surface to the vertical sidewall surface. This dimensional change allows the drive roller to contact the tire on the sidewall rather than the tread, preserving the tread's grip function while enabling torque transmission through a separate rubber strip on the sidewall.
2Duration of action of stationary object
If knurled metal drive rollers are used, then longevity of the roller is improved, but rapid wear is caused to the tire through grooving
Solution Approach 1:
The invention uses a composite material solution by combining a rubber strip on the sidewall with a metal drive roller. The rubber strip provides a compliant contact surface that reduces wear compared to metal-on-tire contact, while the metal roller maintains its longevity. The rubber strip acts as a protective layer between the metal roller and the tire structure.
3Reliability
If notched rubber on the sidewall is used with a notched roller, then torque transmission in wet weather is improved and tread wear is reduced, but precise positioning of the roller and tire is required
Solution Approach 1:
The invention uses a smooth, homogeneous rubber strip surface without notches or patterns. This homogeneous surface provides consistent contact with the drive roller and maintains reliable torque transmission in wet conditions through the rubber's inherent friction characteristics, eliminating the need for precise positioning alignment that notched systems require.
4Loss of substance
If a rubber strip with high Shore A hardness is used on the sidewall, then wear resistance is improved, but torque transmission effectiveness is reduced
Solution Approach 1:
The invention optimizes the rubber strip properties by specifying a Shore A hardness between 55 and 75, which balances wear resistance and torque transmission. This parameter range provides sufficient compliance for effective torque transmission while maintaining adequate wear resistance, avoiding the extremes of too soft (high wear) or too hard (poor torque transmission).
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 tire provides excellent grip and longevity in wet conditions by facilitating simple roller positioning and reducing wear, maintaining effective torque transmission.
Implementation Method 1
a strip of a rubber mixture... forming a smooth outer surface intended to come into contact with a drive roller carrying a plurality of indenters
Implementation Method 2
said rubber mixture of the strip having a Shore A hardness of between 55 and 75, and a glass transition temperature of between -15°C and -0°C
Data Source
Figure 1
AI summary
The invention relates to a tyre (1) of an electrically assisted bicycle or wheelchair, said tyre comprising a crown reinforcement radially inside a tread, said tread being connected, by means of two sidewalls (3), to two beads. The tyre comprises, on at least one of the sidewalls (3) and projecting from the sidewall, a strip (4) of a rubber compound with an axial thickness (ep) of at least 1 mm and not more than 4 mm, at least 10 mm and not more than 30 mm. The rubber compound has a Shore A hardness of between 55 and 75, and a glass transition temperature of between -15°C and 0°C. Said compound forms a smooth outer surface (5) intended to come into contact with a drive roller having a plurality of indenters.