Steering Device Polygonal Friction Connection
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Solution Overview
Problem
Existing steering devices for two- and three-wheeled vehicles face challenges in producing secure, rotationally fixed connections between handlebars and handlebar stems, and between stems and forks, which require precise manufacturing and can result in plastic deformation and increased manufacturing outlay.
Innovation Solution
The implementation of a rotationally fixed connection using smooth cylindrical surfaces for one component and n-sided polygonal surfaces for the other, ensuring a frictional operative connection that optimizes torque transmission without plastic deformation, using a design with a multiplicity of polygonal surfaces to maintain cylindrical shape integrity and reduce production complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interlocking connection with a polygonal cross section is used to ensure a rotationally fixed connection, then the connection security is improved, but the manufacturing precision requirements increase and manufacturing outlay increases
Solution Approach 1:
The invention replaces the polygonal cross-section with a circular cross-section for the handlebar stem. The circular profile allows for a press-fit connection between the stem and handlebars, as well as between the stem and stem tube, eliminating the need for precise polygonal interlocking. This curvature-based approach maintains connection security while significantly reducing manufacturing precision requirements.
2Strength
If pins are used to connect the base to the stem tube in a rotationally fixed manner, then the connection strength is improved, but plastic deformation occurs on the stem tube surface
Solution Approach 1:
The invention removes the pins from the connection system. Instead of using pins to create a rotationally fixed connection between the base and stem tube, the patent employs a press-fit connection relying on friction between the cylindrical surfaces. This extraction of the pin element eliminates the harmful plastic deformation while maintaining sufficient connection strength through optimized frictional contact.
3Reliability
If a press fit is used to connect the lower bearing shell to the stem tube, then the rotationally fixed connection is achieved, but the manufacturing outlay increases
Solution Approach 1:
The invention applies the press-fit connection principle uniformly across multiple interfaces: between the handlebar stem and handlebars, between the stem and stem tube, and between the lower bearing shell and stem tube. This universal application of a single connection method simplifies manufacturing processes and reduces overall manufacturing outlay compared to using different connection methods for different interfaces.
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
This solution enables secure, high-torque transmission without material deformation, reducing manufacturing and installation outlay while maintaining the strength and functionality of components, as the polygonal surfaces introduce a gentle press fit that does not impair the cylindrical connection partners.
Implementation Method 1
The surface, which is in frictional operative connection with this smooth cylindrical surface in the mounted state, of the other component
Data Source
AI summary
The invention proceeds from a steering device for two- and three-wheeled vehicles, which ensures a rotationally fixed connection between handlebars and a handlebar stem and/or between a handlebar stem and a fork of the two- or three-wheeled vehicle, and a steering device for two- and three-wheeled vehicles having a stop. The steering device has a frame with a head tube (1), a fork (2) with a stem tube (3) and a handlebar stem (4) with handlebars (7). In addition, a stop can be provided for the handlebars (7), which consists of a base (12), which is connected in a rotationally fixed manner to the fork (2) of the two- or three-wheeled vehicle, with a recess (14) and a stop element (15), which is securely arranged in the bearing shell (11) and protrudes radially into the recess (14).According to the invention, in each case one component of the rotationally fixed connection has a smooth cylindrical surface over its axial length, whilst the surface, which is in frictional operative connection with this smooth cylindrical surface in the mounted state, of the other component, which is arranged coaxially to that first-mentioned, is constructed as an n-sided polygon.