Prestressed Roller Tracks in Centrifugal Pendulums for Rattle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal pendulum devices in vehicle drivetrains experience noise emission issues due to play between cylindrical rollers and roller tracks, particularly at low speeds during engine start/stop phases, leading to rattling noises and vibrations.
Innovation Solution
A centrifugal pendulum device design featuring open roller tracks in the support flange allows for radial prestressing by a spring washer, reducing play and noise by constantly pressing rollers against the outer contour, enhancing energy absorption and movement coupling of pendulum masses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cylindrical rollers are used to guide pendulum masses in roller tracks, then movement and vibration damping are enabled, but play between rollers and tracks causes noise and rattling at low speeds
Solution Approach 1:
The prestressing element applies a preliminary radial force to press the cylindrical rollers against the roller tracks before operation begins. This pre-compression eliminates play and prevents rattling noises during low-speed operation, particularly during engine starting and stopping phases.
Solution Approach 2:
The support flange is designed with an enlarged installation space in the axial direction to accommodate the prestressing element. This preliminary structural preparation allows the prestressing element to be installed and apply constant radial compression to maintain roller contact with the tracks throughout operation.
2Volume of stationary object
If roller tracks are enclosed to provide support, then roller guidance is achieved, but installation space for prestressing elements is limited
Solution Approach 1:
The roller tracks are designed to be open in the axial direction rather than enclosed radially. This dimensional change in the track geometry creates additional installation space in the axial direction for the prestressing element while maintaining the necessary roller guidance function through the open track structure.
3Object-affected harmful factors
If pendulum masses are suspended with rollers, then vibration damping is achieved, but impact noises occur during starting and stopping phases
Solution Approach 1:
The prestressing element acts as a cushioning element that maintains constant contact between the rollers and roller tracks. This preliminary cushioning prevents impact noises during starting and stopping phases by eliminating gaps and play in the suspension mechanism before impacts can occur.
Solution Approach 2:
The prestressing element changes the force parameter by applying constant radial compression to the rollers. This parameter change ensures consistent contact pressure between rollers and tracks, improving energy absorption capability while reducing impact noises during transient operating conditions.
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
The solution effectively reduces noise generation and pendulum mass deflections, improving vibration damping and balancing across various engine operating states while being cost-effective and simplifying production.
Implementation Method 1
the cylindrical rollers are pressed by a radial force of the prestressing element acting as constantly as possible against the outer contours of the roller tracks
Implementation Method 2
The spring force resulting from this acts against the roller deflection and is thereby able to bring about a reduction in impact noises
Implementation Method 3
the vibrational energy or the vibration amplitude is damped or absorbed by pendulum masses of the centrifugal pendulum device vibrating in the opposite direction to the vibrations being damped
Implementation Method 4
Centrifugal pendulum devices are used for vibration damping, in particular for insulating rotational vibrations, in drivetrains of motor vehicles
Data Source
AI summary
A centrifugal pendulum device for use in a drive train of a vehicle powered by an internal combustion engine includes at least one support flange rotatable about an axis of rotation to which pendulum masses are mounted thereon in a circumferential direction via a bifilar pendulum suspension. The pendulum masses are configured to perform a relative movement with respect to the support flange when a rotational irregularity occurs in the drivetrain under effects of centrifugal force in conjunction with cylindrical rollers which are guided in roller tracks of the support flange. The pendulum masses run in opposite directions to one another and thereby absorb vibrations. The support flange includes roller tracks which are open in a direction of the axis of rotation and all the cylindrical rollers are acted upon by force by a prestressing element radially in the direction of the roller tracks.