Rear Suspension Chainring Compensation for Pedal Kickback
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Solution Overview
Problem
Bicycles with rear suspension experience undesirable chain pull during compression, leading to pedal kickback and destabilization, especially in downhill categories, which can cause chain breakage and loss of rider control.
Innovation Solution
A compensation system is introduced between the chainring and crankset to allow an angular compensation stroke, utilizing interchangeable shock-absorbing and limiting elements to manage the chain pull, with adjustable components for varying disciplines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rear suspension travel is increased to improve wheel absorption capability, then wheel travel performance is improved, but chain pull and pedal kickback increase causing destabilization and potential chain breakage
Solution Approach 1:
A compensation device is introduced as an intermediary mechanism between the chainring and crankshaft. This device includes a compensation element that can rotate relative to the crankshaft, allowing it to absorb the chain pull forces generated by rear suspension compression. The compensation element acts as a mediator that decouples the harmful chain pull from the crankset while maintaining power transmission efficiency.
Solution Approach 2:
The compensation device changes the angular position parameter of the chainring relative to the crankshaft during suspension compression. By allowing the chainring to rotate independently through a limited angular range (compensation stroke), the system adapts to the dynamic conditions caused by wheel travel without transmitting the full impact to the pedals and chain.
2Object-affected harmful factors
If compensation device allows full compensation stroke to eliminate chain pull, then chain pull is reduced, but idle pedaling perception increases reducing pedaling efficiency
Solution Approach 1:
The compensation device is designed to provide only the necessary amount of compensation (partial action) rather than full compensation stroke. The compensation element is constrained to rotate within a limited angular range that is sufficient to counteract chain pull forces during suspension compression, while minimizing the compensation stroke during normal pedaling to maintain pedaling efficiency and reduce idle pedaling perception.
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
Reduces the perception of idle pedaling and enhances pedaling resumption, providing a stable and durable solution for rear suspension bicycles.
Implementation Method 1
a compensation device (40) comprises two main bodies (46, 48) relatively rotatable to each other and integrally respectively to the chairing (26) and the shaft (44), the compensation device (40) also compromises at least one brake element (102) integral with one of the two main bodies (46,48) interposed between a rest end element (104) and a compensation end element (62) integral with the other main body, where the brake element (102) stops alternately against the end elements (104, 62) defining the compensation stroke (A1)
Implementation Method 2
at least one shock-absorbing element (39) is operationally interposed between at least one pair able to deform in correspondence with a final section of the compensation stroke alone (A1)
Implementation Method 3
at least one limiting element (38) is interposed between at least another pair as an alternative to the shock-absorbing element (39) which provides a stop to the respective brake element (102) to limit the maximum deformation of the shock-absorbing element (39)
Data Source
AI summary
A bicycle includes a suspension system of the rear wheel, where the crankset and the hub and sprocket each include at least one chainring engaged by the chain and a rotation shaft. A compensation device is interposed between the toothed plate and the shaft to allow an angular compensation stroke between them from a rest position corresponding to the absence of the pulling of the chain, to a compensation position, corresponding to a pulling action of the chain generated by the rear suspension. The compensation device includes a plurality of pairs of brake elements and respective compensation end elements where at least one shock-absorbing element is operationally interposed between at least one pair capable of deforming only in correspondence with a final portion of the compensations stroke and between at least another pair where at least one limiting element is interposed to limit the maximum deformation of the shock-absorbing element.