Bicycle Drive Unit Step Screw Fastening for Vibration Isolation
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Solution Overview
Problem
Existing bicycle fastening arrangements for drive units are costly due to numerous components and difficult to assemble, while also failing to provide sufficient vibration damping to prevent transmission of vibrations between the drive motor and the frame.
Innovation Solution
A fastening arrangement for bicycles featuring a step screw with reduced components, including a shaft with threaded and unthreaded sections, and screw holders with hollow-cylindrical base bodies, allowing easy assembly and effective vibration damping through materials with damping properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fastening arrangements with multiple components are used, then reliable fastening is achieved, but manufacturing cost increases and assembly complexity increases
Solution Approach 1:
The patent combines multiple fastening components into a single integrated step screw assembly. The step screw integrates the screw shaft, head, and vibration damping elements into one component, eliminating the need for separate fasteners and damping elements. This merging reduces the total component count while maintaining fastening reliability through the integrated design.
Solution Approach 2:
The step screw serves multiple functions simultaneously: it provides mechanical fastening through threading, vibration damping through integrated damping elements, and structural support through its shaft design. This multi-functionality allows a single component to replace what would traditionally require multiple specialized parts, reducing complexity while maintaining performance.
2Stability of the object's composition
If traditional fastening arrangements are used, then structural stability is maintained, but vibration damping is insufficient
Solution Approach 1:
The step screw incorporates vibration damping elements as intermediary components between the fastening interface and the driven object. These damping elements act as mediators that absorb and dissipate vibrational energy, preventing direct transmission of vibrations while maintaining the structural connection. The intermediary damping layer preserves structural stability while eliminating harmful vibration transmission.
Solution Approach 2:
The step screw utilizes composite construction combining different materials with complementary properties: rigid materials for structural stability and vibration-damping materials for harm reduction. This composite approach allows the single component to simultaneously achieve structural integrity and vibration isolation, resolving the contradiction between stability and vibration damping.
3Reliability
If multiple fastening components are assembled, then secure fastening is achieved, but assembly time increases
Solution Approach 1:
By merging multiple fastening and damping components into a single pre-assembled step screw unit, the installation process is simplified to inserting one component rather than assembling multiple parts. This merging maintains fastening security through the integrated design while dramatically reducing assembly time by eliminating multiple assembly steps.
Solution Approach 2:
The vibration damping elements and fastening components are pre-assembled into the step screw during manufacturing before installation. This preliminary action allows the complex multi-component assembly to be performed once during production, then installed as a single unit during bicycle assembly, thereby maintaining security while reducing on-site assembly time.
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
Enables easy and cost-effective mounting and dismounting of the drive unit, while effectively decoupling vibrations between the drive unit and the bicycle frame, enhancing rider comfort.
Implementation Method 1
a step screw (6) for fastening a drive unit (2) to a bicycle frame (3) of the bicycle (1), having a shaft (7) with a threaded section (8)
Implementation Method 2
a shaft step (12), which is arranged between the first round section (9) and the second round section (10) and runs around a screw center axis (11) of the step screw (6)
Implementation Method 3
a first screw holder (14), which has a hollow-cylindrical first base body (16) penetrated by a longitudinal bore (15), and a second screw holder (17), which has a hollow-cylindrical second base body (19) penetrated by a longitudinal bore (18)
Data Source
AI summary
A fastening arrangement for fastening a drive unit to a bicycle frame may include a step screw, a nut, a first screw holder, and a second screw holder. The step screw may include a shaft and a head. The shaft may include a threaded section, a first unthreaded round section arranged on the threaded section, a second unthreaded round section arranged on the first unthreaded round section, and a circumferential shaft step arranged between the first unthreaded round section and the second unthreaded round section. The head may be arranged on the second unthreaded round section of the shaft. The first screw holder may include a first hollow cylindrical base body and a first longitudinal bore extending through the first base body. The second screw holder may include a second hollow cylindrical base body and a second longitudinal bore extending through the second base body.