Steering Damper Quadratic Linkage Geometry
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Solution Overview
Problem
Conventional motorcycle steering damper devices with oscillating dampers have complex structures, are expensive, large, and heavy, and require additional control devices to meet the requirements of varying damping moments based on steering angle and speed, while simpler rotary damper devices lack the necessary control to provide desired damping characteristics.
Innovation Solution
A steering damper device with a rotary damper, actuation lever, and control lever, where the line connecting the pivots intersects the steering stem axis at 0°, allowing the rotary shaft's rotation angle to increase quadratically with steering angle, and incorporating a spring to rotate the rotary shaft in a fixed direction, providing different damping forces during turning and returning, and reducing the oil chamber capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an oscillating damper is used to provide varying damping forces, then the damping characteristics meet the requirements for different steering conditions, but the structure becomes complicated and the device becomes large and heavy
Solution Approach 1:
The patent changes the geometric parameters of the control lever (lengths of links, positions of pivots) to transform the linear steering angle into a quadratic rotation angle of the rotary shaft. This parameter optimization allows a simple rotary damper to achieve the desired nonlinear damping characteristics without complex mechanisms.
2Device complexity
If a rotary damper with simple structure is used, then the device becomes compact and inexpensive, but a complicated control device is needed to meet the damping requirements
Solution Approach 1:
The control lever is designed with asymmetric link lengths and pivot positions relative to the rotary shaft. This asymmetric geometry creates the nonlinear relationship where the rotary shaft rotation angle increases quadratically with the steering angle, enabling the simple rotary damper to provide adaptive damping forces for different steering conditions.
3Device complexity
If the rotary shaft rotation angle increases linearly with steering angle, then the structure is simple, but additional control devices are required to achieve desired damping characteristics
Solution Approach 1:
The control lever employs curved linkages and arc-shaped motion paths to transform the linear steering input into a quadratic rotation output. The geometric curvature of the control lever arms creates the nonlinear relationship between steering angle and rotary shaft rotation, eliminating the need for additional control devices.
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 provides a simple, cost-effective steering damper with symmetric damping force characteristics for both turning and returning, meeting the requirements of varying steering angles and speeds, while minimizing the oil chamber size, thus enhancing the overall performance and reducing the load on the handlebar.
Implementation Method 1
a rotary shaft (13) rotatably supported on the damper case (11); a rotary vane (14) connected to the rotary shaft (13) and rotated by the rotary shaft (13) in the oil chamber (12) of the damper case (11)
Implementation Method 2
a spring (25) connected to at least one of the actuation lever (15) and the control lever (20) so as to rotatably urge the lever to one side
Data Source
AI summary
In a steering damper device, a rotary damper includes a damper case, a rotary shaft rotatably supported on the case, and an actuation lever connected to the rotary shaft; the damper case is mounted to a steering side member; and a tip end of the actuation lever is connected to a frame side member. One end of a control lever is connected to the frame side member via a first pivot. A tip end of the actuation lever is connected to the other end of the lever via a second pivot. The first and second pivots are arranged so that a line connecting the centers of the first and second pivots is substantially intersected by an axis of a steering stem at a steering angle of 0°. Thus, the steering damper device can obtain desired characteristics while using a rotary damper with a simple structure.