Torque Transfer Device with Elastic Damping for Motorcycle Cardan Shafts
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Solution Overview
Problem
Motorcycles with dog clutch transmissions experience torque shocks and noise when engaging first gear, which are propagated through the cardan shaft to the rear wheel, leading to discomfort and noise, especially in cardan drive systems.
Innovation Solution
A torque transmission device with an outer hollow-shaft-like section and an inner shaft section featuring tooth-like elements and elastic elements, along with a compression spring arrangement and friction damping device, allowing relative rotation and asymmetric spring-damping characteristics to absorb and damp torque shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a dog clutch transmission is used to enable fast shifting, then shifting speed is improved, but torque shocks and noise occur during gear engagement
Solution Approach 1:
The patent introduces an intermediary damping device between the inner and outer shaft sections that acts as a mediator to absorb and dampen torque shocks during gear engagement. This damping device, consisting of friction elements and springs, provides a cushioning effect that reduces the harmful torque impulses while allowing the fast shifting characteristics of the dog clutch to be maintained.
Solution Approach 2:
The damping device with friction elements and springs is pre-installed in the cardan shaft to provide beforehand cushioning against torque shocks. The springs are pre-compressed and the friction elements are positioned to engage when torque impulses occur, cushioning the effects before they propagate to the rear wheel and reduce noise before it reaches the rider.
2Object-generated harmful factors
If a two-piece cardan shaft with rubber package is used to absorb torque shocks, then torque shock absorption is improved, but the structure becomes more complex
Solution Approach 1:
The patent applies the nesting principle by placing the damping device with friction elements and springs within the existing two-piece cardan shaft structure. The inner shaft section contains the damping components, which are nested within the hollow outer shaft section. This allows torque shock absorption functionality to be added without significantly increasing overall structural complexity or external dimensions.
3Object-generated harmful factors
If elastic elements with asymmetric spring-damping characteristics are used to dampen torque shocks, then damping effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements asymmetry in the elastic elements by designing them with different geometric characteristics for different directions of rotation. The first and second elastic elements have different spring constants and damping characteristics optimized for their respective rotation directions. This asymmetric design improves torque shock damping effectiveness by providing directionally optimized cushioning, though it does increase manufacturing precision requirements for achieving the specified geometric tolerances.
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 device significantly enhances driving comfort by effectively damping torque shocks and reducing noise during gear engagement, providing a progressive damping characteristic with hysteresis through the geometric design and material choice of elastic and tooth-like elements.
Implementation Method 1
a compression spring arrangement (30) which generates an axial compression force acting on the inner and outer shaft sections
Implementation Method 2
a damping device, which can be a friction damping device, is provided which, when acted upon by the compressive force, damps relative rotations of the inner shaft section in relation to the outer shaft section
Implementation Method 3
The elastic elements can also have damping properties. A relative rotation of the inner shaft section in relation to the outer shaft section results in a characteristic curve which is progressive in both directions of rotation and which, due to the friction damping device and any additional damping properties of the elastic elements, has a certain hysteresis
Data Source
Figure 1~2
AI summary
The device (1) has an outer shaft section comprising tooth type elements (4-7). A spiral spring produces an axial pressure force that acts on the outer shaft section and an inner shaft section, which are designed as tubes (2, 3). A friction damping device or a friction disk arrangement damps relative rotation of the inner section. Elastic elements (13-20) are arranged between the tooth type elements of the outer section and tooth-type elements (8-11) of the inner section. The tooth-type elements are provided succeedingly on top of another in a circumferential direction (12) of the device.