Coil Spring Guide Geometry for Low-Hysteresis Torsional Damping
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Solution Overview
Problem
Existing torsional vibration reduction apparatuses in vehicle transmissions experience increased hysteresis torque due to centrifugal forces, leading to noise issues and reduced damping performance, especially when the lock up clutch is operated from low rotation regions, and current solutions either restrict layout or require additional costly components.
Innovation Solution
The apparatus features guide portions with varying protrusion heights on input and output member spring receiving portions to slidably guide coil springs under centrifugal force, allowing for reduced radial displacement and minimized hysteresis torque without additional components, ensuring effective torsional vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil springs are used to reduce torsional vibration, then damping performance is improved, but hysteresis torque increases due to centrifugal force causing radial displacement and sliding
Solution Approach 1:
The patent accepts the radial displacement caused by centrifugal force as inevitable but converts the harmful sliding effect into a beneficial guiding mechanism. By designing guide portions with varying protrusion heights, the coil springs are intentionally guided to slide along controlled paths, transforming the harmful hysteresis into a predictable and manageable characteristic that maintains damping performance while reducing noise.
Solution Approach 2:
The guide portions are designed with different protrusion heights at different locations around the coil spring receiving portions. This creates local variations in the guiding characteristics, allowing the coil springs to be guided differently at various points during rotation, thereby optimizing the balance between maintaining damping function and controlling hysteresis torque.
2Object-generated harmful factors
If guide portions with varying protrusion heights are used to guide coil springs, then hysteresis torque is reduced, but device complexity increases
Solution Approach 1:
The guide portions are integrated directly into the spring receiving portions of the input and output members, merging the guiding function with the existing structural components. This eliminates the need for separate guiding mechanisms or additional parts, reducing device complexity while still achieving the hysteresis reduction benefit.
Solution Approach 2:
The varying protrusion heights of the guide portions are formed as integral features of the spring receiving portions themselves, allowing the structure to guide the coil springs through its own geometry without requiring external guiding components. The structure serves its own guiding function, simplifying the overall device design.
3Object-generated harmful factors
If coil springs are constrained to prevent radial displacement, then hysteresis torque decreases, but layout flexibility is restricted
Solution Approach 1:
Instead of using rigid constraints to prevent radial displacement, the patent employs dynamic guiding through the varying protrusion heights of the guide portions. This allows the coil springs to move radially in a controlled manner during rotation, adapting to the centrifugal force while maintaining guidance, thereby preserving layout flexibility while still reducing hysteresis torque.
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 configuration effectively reduces hysteresis torque and associated noise, enhancing damping performance while maintaining layout flexibility and avoiding the need for costly additives, thereby improving fuel efficiency and reducing uncomfortable vibrations.
Implementation Method 1
elastic deformation of the coil springs between the forward rotation side spring pedestals of the output member and the forward rotation side spring pedestals of the input member is occurred
Implementation Method 2
centrifugal force which is applied to the coil springs can be affected to the hysteresis characteristic. That is, under the circumstance that the input and output members rotate with high speed, centrifugal force displaces the coil springs in a radial outward direction
Implementation Method 3
the coil springs are abutted to or are slid to the inner circumferential surface of the input and output coil spring receiving portions in the coil spring end portions where the displacement in a radial direction is maximized
Data Source
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AI summary
The present invention relates to a torsional vibration reduction apparatus which uses coil springs and can obtain expected torsional vibration reduction performance by reducing the hysteresis torque caused by the sliding of coil springs (50) without restricting the layout and requiring the additive components. The coil springs (50) are received in paired input member side coil spring receiving portions (44) and an output member side coil spring receiving portion (48) . The paired input member side coil spring receiving portions (44) comprise forward rotation side and reverse rotation side guide portions (44-1a) and (44-1b) between forward rotation side and reverse rotation side spring pedestals (44a) and (44b). The output member side coil spring receiving portion (48) comprises forward rotation side and reverse rotation side guide portions (48-1a) and (48-1b) between forward rotation side and reverse rotation side spring pedestals (48a) and (48b). In both the forward rotation and the reverse rotation, since the displacement of the coil springs (50) under the centrifugal force is received by the guide portions (44-1a), (48-1b); and (44-1b), (48-1a) and the vertical component force of the elastic force is small, the sliding resistance is suppressed, the hysteresis torque is reduced, the additive components is not required, and the installation positions of the coil springs (50) cannot be restricted.