Prestressed Roller Guidance in Centrifugal Pendulums for Rattle Reduction
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Solution Overview
Problem
Centrifugal pendulum devices in internal combustion engine-driven vehicles face challenges in reducing noise emissions, particularly during low-speed operations like starting and stopping, due to rattling noises from pendulum mass and roller movements, leading to vibrations and imbalance.
Innovation Solution
The centrifugal pendulum device incorporates open roller conveyors with a prestressing element, such as a spring ring, to maintain constant contact between cylindrical rollers and roller tracks, reducing play and noise through radial force application, and enhancing energy absorption and movement coupling of pendulum masses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional closed roller tracks are used to guide cylindrical rollers, then the structure is stable and robust, but play between rollers and tracks causes noise and vibration during low-speed operations
Solution Approach 1:
A prestressing element is introduced that applies a preliminary radial force to press the cylindrical rollers against the outer contours of the roller tracks before operation begins. This pre-compression ensures continuous contact between rollers and tracks, eliminating play and preventing the rattling noises that occur during low-speed operations when centrifugal forces are insufficient to maintain contact.
Solution Approach 2:
The roller tracks are designed with open inner contours instead of closed contours, changing the geometric parameter of the track structure. This modification allows the prestressing element to access and apply force to the rollers from the inside, enabling the noise reduction mechanism while maintaining structural integrity.
2Object-affected harmful factors
If a prestressing element is added to eliminate play between rollers and tracks, then noise emission is reduced, but the device complexity increases
Solution Approach 1:
The prestressing element serves multiple functions simultaneously: it applies radial pre-compression to eliminate roller play, absorbs vibrations through its elastic properties, and can be integrated with the existing support flange structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving noise reduction.
Solution Approach 2:
The prestressing element is designed to be nested within the existing structure of the centrifugal pendulum device, specifically within the support flange and roller track assembly. This nesting approach allows the prestressing element to be accommodated without significantly increasing the overall device volume or requiring major structural modifications, thus limiting complexity increase.
3Object-affected harmful factors
If open roller tracks are used to accommodate the prestressing element, then installation space is increased and noise is reduced, but the support flange mass increases
Solution Approach 1:
The prestressing element is designed as a thin, flexible elastic component that can deform to apply radial force to the rollers. This thin-film approach minimizes the mass of the prestressing element itself, thereby limiting the increase in support flange mass while still achieving the noise reduction effect through continuous roller contact.
Solution Approach 2:
The support flange is designed with a composite structure that integrates the open roller tracks and accommodates the prestressing element. This composite design optimizes the distribution of material, placing mass only where structurally necessary, thereby minimizing the overall mass increase while maintaining the structural integrity required to support the noise reduction mechanism.
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 effectively reduces noise emissions and improves vibration damping across all operating states, including start-stop phases, by ensuring constant contact and uniform deflection of pendulum masses, thereby minimizing imbalance and vibrations, while being cost-effective and efficient.
Implementation Method 1
a one-piece or multi-piece pretensioning element (14), in particular a spring ring, which acts on all cylindrical rollers (9) with a radial force
Implementation Method 2
the non-slip cylindrical rollers are also coupled to each other by the one-piece or multi-piece preloading element
Implementation Method 3
The vibration energy or amplitude is damped or eliminated by the pendulum masses of the centrifugal pendulum device oscillating in the opposite direction to the vibrations to be dampened
Implementation Method 4
pendulum masses distributed around the circumference are assigned to a support or pendulum flange and are suspended from the support flange in a plane of rotation
Data Source
Figure 1
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AI summary
The invention relates to a centrifugal pendulum device (1) which is intended for use in a drive train of a vehicle powered by an internal combustion engine. The centrifugal pendulum device (1) consists of at least one support flange (3) which rotates about an axis of rotation (2) and with which pendulum masses (6, 7) are associated via a bifilar pendulum suspension (8) in the circumferential direction. If a rotational irregularity occurs, the pendulum masses (6, 7), in conjunction with cylindrical rollers (9) which are guided in mutually opposing roller tracks (10, 11) of the support flange (3) and of the pendulum masses (6, 7), execute a movement relative to the support flange (3) under centrifugal force and in the process dampen vibrations. The support flange (3) encloses open roller tracks (10) in the direction of the axis of rotation (2), wherein a force is applied to all the cylindrical rollers (9) radially in the direction of the roller tracks (10) by a pre-stressing element (14).