Centrifugal Pendulum Damping Order Tuning for Engine Torque Vibration
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Solution Overview
Problem
Existing vibration damping devices with a restoring force generation member and an inertial mass body do not achieve optimal vibration damping performance even when the order of vibration is aligned with the excitation order of the drive device, indicating a need for improved design to enhance damping efficiency.
Innovation Solution
The vibration damping device is designed with a reference order higher than the excitation order of the engine by adjusting the interaxial distances and moments of inertia, allowing the inertial mass body to swing in conjunction with the restoring force generation member, effectively increasing the order of vibration damping beyond the excitation order and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the order of vibration is aligned with the excitation order of the drive device, then the vibration damping performance is improved, but the damping effectiveness is insufficient when torque fluctuation amplitude increases
Solution Approach 1:
The patent employs a centrifugal pendulum vibration absorber where the effective order qeff is dynamically adjusted through the relationship between the pendulum's moment of inertia J2, the distance L3 from the rotation axis to the pendulum's center of gravity, and the distance L4 between coupling points. The formula qeff = (J1 + J2) / (J1 + m*L3*L4) demonstrates that the effective order can be tuned to exceed the excitation order q, allowing the system to adapt to varying torque fluctuation amplitudes and maintain damping effectiveness across different operating conditions.
2Reliability
If the reference order is set higher than the excitation order, then the vibration damping performance is significantly improved, but the device complexity increases
Solution Approach 1:
The patent achieves higher reference order through parameter optimization rather than structural complexity. By adjusting the moment of inertia J2 of the pendulum mass, the distance L3 from the rotation axis to the pendulum's center of gravity, and the coupling distance L4, the system attains an effective order qeff > q. The design formula qeff = (J1 + J2) / (J1 + m*L3*L4) provides a clear parameter relationship that guides implementation without requiring complex mechanisms.
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 design significantly improves vibration damping performance by ensuring the reference order is higher than the excitation order, effectively damping vibrations even when the amplitude of input torque increases, thereby enhancing the device's ability to manage vibrations across various rotational speeds.
Implementation Method 1
a flywheel mass body that receives a centrifugal force and that functions as a restoring force generation member
Implementation Method 2
vibration of the support member can be damped by vibration transferred from the inertial mass body to the support member
Data Source
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AI summary
A vibration damping device is disposed in an oil chamber, and includes: a support member that rotates together with a rotary element, to which torque from an engine is transferred, about the center of rotation of the rotary element; a restoring force generation member that is coupled to the support member and that is swingable along with rotation of the support member; and an inertial mass body coupled to the support member via the restoring force generation member and swung about the center of rotation in conjunction with the restoring force generation member along with rotation of the support member. The order of the vibration damping device is larger than the sum of the excitation order of the engine and an offset value determined in consideration of the effect of oil in the oil chamber. The reference order, which is a convergent value of the order of the vibration damping device which operates in the oil chamber when the amplitude of vibration of input torque transferred to the rotary element becomes smaller, is higher than the excitation order.