Vehicle Freewheel Helical Coupling for Low-Wear Tooth Engagement
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Solution Overview
Problem
Existing freewheels in vehicles, such as electric bicycles, face issues with wear and noise due to the engagement and disengagement of teeth, which can lead to undesirable slipping and mechanical malfunctions.
Innovation Solution
A freewheel design featuring a crankshaft, output shaft, freewheel element, and friction element coupled via a helical mechanism, allowing for torque transmission through a spur toothing system that engages and disengages via a spiral mechanism, reducing wear and noise by preventing slipping and ensuring robust mechanical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a toothed mechanism is used for freewheel engagement, then torque transmission is achieved, but wear and noise increase due to slipping during engagement and disengagement
Solution Approach 1:
A friction element is introduced as an intermediary between the toothed sections to mediate the engagement process. The friction element gradually brings the teeth into contact through frictional force, preventing sudden impacts and slipping. This intermediary mechanism reduces wear and noise while ensuring reliable torque transmission through controlled engagement.
2Reliability
If spring-loaded engagement is used, then the freewheel mechanism is robust, but complexity increases due to additional components
Solution Approach 1:
The helical mechanism converts rotational motion directly into the axial movement needed for engagement and disengagement. The system uses its own operational motion (rotation) to automatically control the engagement process without requiring external spring-loaded components. This self-service approach maintains mechanical robustness while reducing component complexity.
3Device complexity
If direct mechanical coupling is used for all movements, then simplicity is achieved, but malfunctions occur due to lack of controlled engagement
Solution Approach 1:
The engagement mechanism transitions from static direct coupling to dynamic controlled engagement. The helical mechanism dynamically adjusts the axial position of the friction element based on rotational direction and speed, enabling controlled engagement and disengagement. This dynamic approach prevents malfunctions while maintaining relative structural simplicity.
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 design provides a reliable, low-wear, and low-noise freewheel operation by ensuring precise engagement and disengagement of the tooth mesh, preventing slipping and enhancing the mechanical robustness of the freewheel mechanism.
Implementation Method 1
a friction element (5). A predetermined frictional connection is formed between the output shaft and the friction element in the circumferential direction of the output shaft
Implementation Method 2
The freewheel element and the friction element are coupled to each other by means of a helical mechanism. The helical mechanism is designed to cause a translational displacement of the freewheel element and the friction element relative to each other when the freewheel element and the friction element rotate relative to each other
Data Source
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AI summary
The invention relates to a freewheel for a vehicle (100), in particular a two-wheeler, comprising a crankshaft (2), an output shaft (3) having a first toothed section (11), a freewheel element (4) having a second toothed section (12), and a friction element (5), wherein the first toothed section (11) and the second toothed section (12) are arranged to effect torque transmission between the output shaft (3) and the freewheel element (4) when engaging with each other, wherein the freewheel element (4) is arranged to be axially displaceable on the crankshaft (2), wherein the freewheel element (4) is arranged circumferentially non-rotatable relative to the crankshaft (2), and wherein the freewheel element (4) and the friction element (5) are connected to each other by means of a helical mechanism (6) which is arrangedto cause a translational displacement of the freewheel element (4) and the friction element (5) relative to each other during a relative rotation of the freewheel element (4) and the friction element (5).