Bicycle Stem Suspension Elastomer Ring Design
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Solution Overview
Problem
Existing steering devices for two-wheelers, such as bicycles, face challenges in maintaining driving stability and comfort due to large spring deflections in telescopic forks, especially during braking, which lead to reduced steering angle and increased wear on components, and complex, costly spiral spring arrangements in stem suspensions.
Innovation Solution
A stem spring system utilizing an elastomer ring element with adjustable preload, supported by a rebound stop and needle bearings, provides a simple, maintenance-free solution for enhancing ride comfort by allowing large spring deflections while preventing pull-out and adjusting response behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If telescopic forks with springing elements are used to increase driving comfort, then ride comfort is improved, but large spring deflections occur during braking which reduce steering angle and stability
Solution Approach 1:
The invention extracts the springing function from the fork assembly and relocates it to the stem area. The fork itself becomes rigid, while the stem incorporates spring elements (elastomer ring or coil springs) that provide suspension independently of the fork's steering mechanism, thereby preventing spring deflection from affecting steering angle.
Solution Approach 2:
The suspension function is segmented from the steering function. The fork handles steering while the stem handles suspension, allowing each system to operate independently without interfering with the other's performance characteristics.
2Reliability
If telescopic forks with large spring deflection are used, then ride comfort is improved, but wear on sliding surfaces of standpipes and dip tubes increases leading to high maintenance
Solution Approach 1:
The springing function is extracted from the fork's telescopic mechanism and placed in the stem assembly. This eliminates the sliding surfaces and dip tubes in the fork, replacing them with a spring mechanism in the stem that has fewer wear-prone components.
Solution Approach 2:
The mechanical sliding contact system in telescopic forks is replaced with a spring-based suspension system in the stem, reducing friction and wear on critical components.
3Reliability
If spiral spring arrangements are used in stem suspensions, then suspension function is achieved, but the arrangements are complicated and costly with limited design freedom
Solution Approach 1:
The invention changes the physical state and form of the spring element from complex spiral arrangements to simple elastomer ring elements or single coil springs. This parameter change simplifies the design while maintaining the suspension function, and increases design freedom through various elastomer geometries and mounting configurations.
Solution Approach 2:
The invention replaces expensive, complex spiral spring arrangements with simpler, more economical elastomer ring elements that can be easily manufactured and replaced if needed.
4Reliability
If the steerer tube is secured with adjusting rings or clamp sleeves, then pull-out prevention is achieved, but the design becomes more complex with additional components
Solution Approach 1:
The invention combines the pull-out prevention function with the existing headset adjusting mechanism. The spring-loaded stem shaft utilizes the same adjusting ring or clamp sleeve that secures the steerer tube, eliminating the need for separate pull-out prevention components and reducing overall device complexity.
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 solution improves ride comfort on level surfaces by reducing spring deflections and maintaining stability, making it suitable for urban and e-bike applications without the need for additional sealing or complex designs, and can be easily retrofitted into existing systems.
Implementation Method 1
an elastomer ring element with free peripheral surfaces is arranged, through which the stem shaft is guided and further into the steerer tube, so that when there is a driving-related supporting force on the stem the stem shaft dips into the steerer tube, with the elastomer ring element being deformable
Implementation Method 2
supported by springs. The stem arrangement of the vertical stem shaft and the horizontal stem can be made in one piece or in two parts
Data Source
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AI summary
The invention relates to a steering device for a two-wheeler, in particular a bicycle, with a stem suspension, comprising a frame-side head tube (2) in which a fork steerer (7) of a front fork (3) is pivotably received, and a threaded headset in which an adjusting ring (8) is screwed onto the fork steerer (7) or alternatively a threadless headset with a clamping sleeve (26) in each case for securing the position of the fork steerer (7) in the head tube (2) and for adjusting a bearing play, wherein the stem suspension has a telescopic arrangement in which a stem (15) of a stem arrangement (14) consisting of a vertical stem (15) and a horizontal stem (4) is received in the fork steerer (7) in a rotationally fixed manner and is resiliently supported.According to the invention, for a resilient support of the stem (4) between the adjusting ring (8) or alternatively between the clamping sleeve (26) and the stem (4), an elastomer ring element (24) with free circumferential surfaces is arranged, through which the stem shaft (15) is guided and further into the fork steerer tube (7), so that when a driving-related supporting force is applied to the stem (4) the stem shaft (15) plunges into the fork steerer tube (7), wherein the elastomer ring element (24) is deformable in a restoring manner.