Centrifugal Pendulum Axial Preload for Low-Speed Vibration Isolation
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Solution Overview
Problem
Centrifugal pendulums in friction clutches face limitations in effectively supporting pendulum masses in the axial direction, particularly at low speeds, leading to reduced vibration isolation due to high torque fluctuations and potential contact with the oscillating chamber boundaries.
Innovation Solution
The pendulum masses are prestressed in the axial direction via a first prestressing element, which contacts them radially, providing support and adjusting the friction effect to slow down displacement, allowing effective vibration absorption across a broader frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pendulum masses are supported against the axial direction at the inner region, then the axial support is provided, but the support effectiveness is insufficient at low speeds leading to boundary contact
Solution Approach 1:
The support point is moved from the inner region to the outer region of the pendulum mass, changing the radial position dimension. This dimensional change increases the lever arm for axial support, thereby improving support effectiveness without compromising the vibration isolation function.
Solution Approach 2:
The preload element applies a pre-tensioning force to the pendulum mass in the axial direction before operation. This preliminary action ensures that the pendulum mass is firmly supported against axial displacement from the start, preventing boundary contact even at low speeds where centrifugal forces are insufficient.
2Ease of operation
If the pendulum masses are pre-tensioned at the outermost point, then the axial support is maximized, but the friction effect for controlling displacement is reduced
Solution Approach 1:
The support surface is designed with a specific radial position (outer region but not at the absolute outermost point) that provides different local qualities: sufficient lever arm for axial support while maintaining adequate normal force for friction control. This local optimization balances both requirements.
Solution Approach 2:
The radial position parameter of the support point is optimized to a specific value in the outer region. This parameter change simultaneously achieves improved axial support effectiveness through increased lever arm while maintaining sufficient friction effect through adequate normal force generation.
3Ease of operation
If the support point is moved to the outer region, then the axial support effectiveness is improved, but the distance from the axis of rotation increases affecting the oscillation characteristics
Solution Approach 1:
The support is applied at a specific local region in the outer area rather than uniformly. This localized support position optimizes the balance between axial support effectiveness and oscillation characteristics by choosing a radial position that provides sufficient lever arm while minimizing impact on oscillation frequency.
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 enhances the centrifugal pendulum's ability to absorb engine-excited vibrations by ensuring consistent support and adjustable friction, thereby improving vibration isolation across the entire frequency range, including low speeds.
Implementation Method 1
The pendulum masses can oscillate along their tracks in the field of centrifugal acceleration when excited by torque fluctuations from an internal combustion engine
Implementation Method 2
These oscillations extract and replenish energy from the excitation vibration at appropriate times, thus dampening the excitation vibration, with the centrifugal pendulum acting as a damper
Implementation Method 3
The pendulum masses are pre-tensioned axially relative to the at least one flange by means of at least one first pre-tensioning element... allowing effective vibration absorption across a broader frequency range
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a centrifugal pendulum (1), at least comprising at least one flange (2, 3) and a plurality of pendulum masses (4), wherein: - the pendulum masses (4) are arranged on the at least one flange (2, 3) for movement at least in a radial direction (5) relative to an axis of rotation (6) and relative to the at least one flange (2, 3); - the pendulum masses (4) are preloaded with respect to the at least one flange (2, 3) in an axial direction (8) by at least one first preloading element (7); - the pendulum masses (4) have an extent (9) in the radial direction (5) between an innermost point (10) and an outermost point (11) of the pendulum masses (4); - the at least one first preloading element (7) contacts the pendulum masses (4) in a first region (12), which is arranged at a distance (13) from the outermost point (11) in the radial direction (5) of at most 5% of the extent (9).