Dynamic Damper Hysteresis Torque Variation
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Solution Overview
Problem
Existing lock-up devices in fluid type power transmission systems struggle to inhibit variation in rotational speed across a wide range, especially at lower lock-up rotational speeds, due to the limitations of hysteresis torque generation mechanisms, which also lead to increased device size and cost.
Innovation Solution
A dynamic damper device is introduced, comprising a pair of plates, an annular hub flange, an inertia member, and a hysteresis torque generating mechanism, where the hysteresis torque varies with rotational speed ranges, allowing for reduced rotational speed variation without enlarging the device, using a simple structure that includes sliders and a pressing mechanism to generate variable torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the lock-up rotational speed is set to be low to enhance fuel consumption, then fuel efficiency is improved, but variation in output-side rotational speed increases
Solution Approach 1:
The hysteresis torque generating mechanism dynamically adjusts the hysteresis torque magnitude based on rotational speed ranges. At lower rotational speeds, a larger hysteresis torque is generated to suppress rotational speed variation, while at higher speeds, the torque is reduced. This dynamic adaptation allows the system to maintain stability across a wide rotational speed range while operating at low lock-up speeds for improved fuel efficiency.
Solution Approach 2:
The mechanism changes the hysteresis torque parameter according to rotational speed conditions. By varying the hysteresis torque magnitude based on the operational speed range, the system optimizes both fuel consumption and rotational speed stability, resolving the contradiction between low lock-up speed operation and rotational speed variation suppression.
2Stability of the object's composition
If a hysteresis torque generating mechanism is added to inhibit rotational speed variation, then rotational speed stability is improved, but device complexity increases
Solution Approach 1:
The hysteresis torque generating mechanism is merged with the existing dynamic damper device structure. The mechanism utilizes the rotational movement between the hub flange and the pair of plates that are already present in the dynamic damper, eliminating the need for separate additional components. This integration achieves rotational speed stabilization while minimizing increases in device complexity.
Solution Approach 2:
The hub flange and pair of plates serve multiple functions: they provide the structural connection in the dynamic damper device and simultaneously act as the rotating elements that generate hysteresis torque for rotational speed stabilization. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity.
3Loss of energy
If the hysteresis torque generating mechanism is designed to work at low rotational speeds, then fuel consumption is reduced, but the mechanism size increases
Solution Approach 1:
The hysteresis torque generating mechanism is combined with the existing dynamic damper device components, specifically utilizing the hub flange and pair of plates. This merging approach allows the mechanism to achieve low-speed operational effectiveness without requiring separate additional space, thereby preventing an increase in overall mechanism size while enabling reduced lock-up rotational speeds for improved fuel consumption.
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 effectively inhibits rotational speed variation across a wide range, enabling lower lock-up rotational speeds and reducing fuel consumption, while maintaining a compact device size and reducing costs by using a minimal number of components.
Implementation Method 1
The elastic member elastically couples the pair of plates and the hub flange in a rotational direction
Implementation Method 2
The hysteresis torque generating mechanism is configured to generate a variable hysteresis torque between the pair of plates and the hub flange
Implementation Method 3
The inertia member is fixed to the hub flange... the inertia member and the torsion springs function as a dynamic damper, and these components attenuate variation in rotational speed of the output-side member
Data Source
AI summary
A dynamic damper disposed between a piston of a lock-up device and a turbine hub of a fluid type power transmission device includes a pair of plates into which a torque is inputted and that is allowed to be coupled to the turbine hub, a hub flange, an inertia member fixed to the hub flange, a torsion spring, and a hysteresis torque generating mechanism. The hub flange is disposed between the pair of plates while being rotatable relative to the pair of plates. The torsion spring elastically couples the pair of plates and the hub flange. The hysteresis torque generating mechanism is disposed on an inner peripheral side of the hub flange while being disposed between the pair of plates, and is configured to generate a variable hysteresis torque between both plates and the hub flange.