E-Bike Drive Unit Mounting With Floating Bolt Tolerance Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fastening arrangements for electric bicycle drive units face challenges in securely attaching mid-motor drive units to bicycle frames due to production-related tolerances, requiring additional components to compensate for tolerance gaps and increasing manufacturing and assembly complexity.
Innovation Solution
A simplified fastening arrangement using a single-piece floating bearing threaded bolt that bridges tolerance gaps between the drive unit housing flanges and the bicycle frame legs, providing a stable connection for high mechanical forces through a non-positive contact, reducing the need for separate components and assembly steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-piece floating bearing threaded bolt is used to fasten the drive unit, then the device complexity and manufacturing cost are reduced, but the ability to compensate for tolerance gaps may be insufficient
Solution Approach 1:
The patent combines the floating bearing frame leg and the threaded fastening element into a single integrated component (the floating bearing threaded bolt). This merging eliminates the need for separate compensation mechanisms while maintaining the ability to bridge tolerance gaps through the threaded connection design, thereby reducing device complexity without sacrificing precision compensation capability.
Solution Approach 2:
The floating bearing threaded bolt serves multiple functions simultaneously: it acts as the fastening element, the floating bearing frame leg, and the tolerance gap compensator. This multi-functionality allows a single component to achieve what previously required multiple parts, reducing overall device complexity while maintaining effective tolerance compensation.
2Reliability
If multiple separate components are used to compensate for tolerance gaps, then the compensation effectiveness is improved, but the manufacturing cost and assembly effort increase
Solution Approach 1:
The patent integrates the tolerance gap compensation function directly into the floating bearing threaded bolt design. The threaded portion allows for adjustable positioning to accommodate tolerance variations, while the integrated structure eliminates the need for separate compensation components, thereby maintaining reliability while significantly improving ease of manufacture and reducing assembly complexity.
Solution Approach 2:
The floating bearing threaded bolt is pre-designed with threaded sections that enable easy adjustment during assembly to compensate for tolerance gaps. This preliminary design feature allows for quick adaptation to manufacturing variations without requiring complex adjustment mechanisms or multiple components, reducing both manufacturing cost and assembly effort while maintaining effective tolerance bridging.
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 effectively transmits large static and dynamic forces while reducing manufacturing costs and assembly effort by establishing a stable, force-fit connection between the drive unit and the bicycle frame using a single fastening element, ensuring reliable attachment even under high loads.
Implementation Method 1
very high mechanical forces can briefly act on the drive unit, which forces are transmitted to the bicycle frame by the fastening arrangement
Implementation Method 2
non-positive connection is to be understood as a direct contact between the fixed bearing housing flange and the fixed bearing frame piece, via which, ideally, very high forces occurring parallel to and in the contact plane are transmitted
Implementation Method 3
a threaded section with an external thread, which is screwed into a corresponding internal thread on the fixed bearing frame piece or on one of the two housing flanges
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an electric bicycle drive unit mounting arrangement (50; 150) for attaching an electric drive unit (20) to a drive receptacle (10) of a bicycle frame (12), wherein the bicycle frame (12) has a fixed-bearing frame leg (14) and a parallel floating-bearing frame leg (16), wherein a drive unit housing (22) has a fixed-bearing housing flange (44; 144) and a parallel floating-bearing housing flange (46; 146), wherein the fixed-bearing housing flange (44; 144) is frictionally attached directly to the fixed-bearing frame leg (14), and wherein a floating-bearing mounting element is provided for attaching the floating-bearing housing flange (46; 146) to the floating-bearing frame leg (16), and wherein the floating-bearing mounting element as loose bearing threaded bolts (60;160) is formed, which has a cylindrical bolt head (61) that sits radially free of play in a floating bearing cylindrical bore (80) of the floating bearing frame leg (16), and has a threaded section (66;200) with an external thread (67;202) that is screwed into a corresponding internal thread (72;147) on the fixed bearing frame leg (14) or on one of the housing flanges (146).