Bicycle Derailleur Damping Device Nested Within Spring
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Solution Overview
Problem
Existing bicycle derailleurs face challenges in maintaining optimal chain tension and structural compactness, with issues such as increased damper moment variability over time, limited bearing spacing, and complex assembly processes that can lead to inefficiencies and potential damage from collisions.
Innovation Solution
A rear bicycle derailleur design featuring a base element, movable element, rotary shaft, and chain guide assembly with a damping device that includes a coupling device radially positioned within an elastic force store device, providing a compact and robust structure with improved bearing spacing and simplified assembly through a modular spring-damper unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the damping device is arranged radially outside the elastic force store device, then the assembly is easier to manufacture, but the axial length increases and structural compactness is reduced
Solution Approach 1:
The damping device is nested radially within the elastic force store device, with the damping element positioned inside the spring element. This nested arrangement allows the damping device to be integrated into the existing axial space of the elastic force store device, maintaining compact axial length while enabling the damping function. The coupling element connects the damping device to the rotary shaft, allowing the damping force to be applied without increasing the overall axial footprint.
2Volume of moving object
If the damping device is arranged radially within the elastic force store device, then the axial length is reduced, but the assembly complexity increases
Solution Approach 1:
The damping device and elastic force store device are merged into a single integrated assembly. The damping element and spring element are positioned concentrically within the same radial space, sharing the same axial region. This merging allows both damping and elastic functions to be achieved within the same structural envelope, reducing axial length while the coupling element provides a unified interface for connecting to the rotary shaft, thereby managing assembly complexity through functional integration.
3Ease of manufacture
If the coupling device is positioned axially outside the elastic force store device, then the assembly is simpler to manufacture, but the structural compactness is reduced
Solution Approach 1:
The coupling device is positioned axially within the elastic force store device, utilizing the radial space created by the nested damping element. This dimensional reorganization allows the coupling device to be integrated into the axial region rather than extending radially outward, maintaining structural compactness while the coupling element provides the necessary connection interface for transmitting damping forces to the rotary shaft.
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 enhances chain tension stability, reduces the risk of chain slippage, and facilitates efficient production by ensuring a consistent damper moment and improved structural integrity, while also reducing the risk of collisions and assembly complexities.
Implementation Method 1
a first elastic force store device (44) which is configured to exert on the chain guide assembly (25) a preload force which preloads the chain guide assembly (25) in a first direction of rotation relative to the movable element (16)
Implementation Method 2
a damping device (38) which is configured to, via the rotary shaft (50), exert a damping force on the chain guide assembly (25) and support an opposing force, which corresponds to the damping force, on a support which is static in relation to the movable element (16)
Data Source
AI summary
A bicycle derailleur includes a base element, a movable element having a receptacle and movably coupled to the base element, a rotary shaft mounted in the movable element in the receptacle to be rotatable about an axis of rotation, and a chain guide assembly rotatable relative to the movable element about the axis of rotation and which is coupled rotationally conjointly to the rotary shaft. An elastic force store device exerts on the chain guide assembly a preload force which preloads said chain guide assembly in a direction of rotation relative to the movable element. A damping device acts directly or indirectly between the movable element and the chain guide assembly and has a coupling device arranged radially within the first elastic force store device by which the damping device is coupled to a support, which is static in relation to the movable element, and the rotary shaft.