Design and Construction of a Machine to Evaluate the Forces in Roller Chain Drives

1992 ◽  
Author(s):  
James C. Conwell ◽  
Glen E. Johnson ◽  
S. W. Peterson
Keyword(s):  
Experimental Investigation ◽  
Impact Force ◽  
Normal Operation ◽  
Test Machine ◽  
Chain Drive ◽  
Roller Chain ◽  
Wide Range ◽  
The Impact ◽  
Chain Drives ◽  
Design And Construction

Abstract In this article, a brief history of chain drives is presented, and the design and construction of a machine to investigate chain drive force phenomena is discussed. The new test machine allows the measurement of the impact force between a roller and the sprocket during “seating” and it can also be used to measure the forces that exist in the link sides plates during normal operation (including start-up and shut down conditions). Data can be obtained for a wide range of chain loads and speeds. Two companion papers (“Experimental Investigation of the Impact Force that Occurs When a Roller Seats on the Sprocket During Normal Operation of a Roller Chain Drive” and “Experimental Investigation of the Forces in a Link Side Plate During Normal Operation of a Roller Chain Drive”, both presented at this conference) describe experiments that have been completed with this test machine.

Experimental Investigation of the Forces in a Link Side Plate During Normal Operation of a Roller Chain Drive

1992 ◽  
Author(s):  
James C. Conwell ◽  
Glen E. Johnson ◽  
S. W. Peterson
Keyword(s):  
Experimental Investigation ◽  
Unit Length ◽  
Linear Chain ◽  
Normal Operation ◽  
Test Machine ◽  
Side Plate ◽  
Inertia Effects ◽  
Roller Chain ◽  
Wide Range ◽  
The Impact

Abstract The fluctuation in the tension of a chain link during normal operation is very likely the root cause of chain stretch and fatigue in roller chain drives. In this paper we present the results from a recent experimental investigation of this tension variation phenomenon. The experimental procedure is described, and data are presented for a wide range of initial tensions, transmitted loads, and chain speeds. At low speeds, the data give reasonable agreement with previously published theoretical models for quasi-static load distribution. However, at higher speeds (where inertia effects are more significant) the experimental results indicate that quasi-static models do not provide an adequate explanation. The differences are noted and discussed. An empirical equation for “tight side” chain tension is presented in terms of torque transmitted, sprocket pitch radius, mass per unit length of chain, and linear chain speed. This paper is accompanied by companion papers that describe the design and construction of the test machine and the measurement of the impact force as a roller seats on the sprocket.

Experimental Investigation of the Impact Force That Occurs When a Roller Seats on the Sprocket During Normal Operation of a Roller Chain Drive

1992 ◽  
Author(s):  
James C. Conwell ◽  
Glen E. Johnson ◽  
S. W. Peterson
Keyword(s):  
Experimental Investigation ◽  
Effective Mass ◽  
Relative Velocity ◽  
Impact Force ◽  
Empirical Relation ◽  
Normal Operation ◽  
Practical Concern ◽  
Wide Range ◽  
Noise Vibration ◽  
The Impact

Abstract As a roller “seats” onto a sprocket, an impact force occurs between these two elements due to the relative velocity between the roller and the sprocket tooth recess. This impact force is of interest because it can be related to chain noise, vibration, wear, and other phenomena of practical concern in the performance of chain drives. The magnitude of the impact force is equal to the product of the effective mass, the relative velocity, and the reciprocal of the time associated with the impact event. Unfortunately, it is difficult to estimate the effective mass, relative velocity, and appropriate impact time in order to estimate the impact force. In this paper we present the results from a recent experimental investigation of this impact force. The experimental procedure is described, and data are presented for a wide range of initial tensions, transmitted loads, and chain speeds. As might be expected, impact force increases rapidly with increases in chain speed. An empirical relation for impact force as a function of chain speed and chain tension is presented and general observations about the data are presented and discussed.

Reduction of Noise and Vibration in Roller Chain Drives

1977 ◽  
Vol 191 (1) ◽  
pp. 363-370 ◽  
Author(s):  
S. W. Nicol ◽  
J. N. Fawcett
Keyword(s):  
High Frequency ◽  
Noise Level ◽  
Experimental Tests ◽  
Chain Drive ◽  
Noise And Vibration ◽  
High Frequency Vibration ◽  
Roller Chain ◽  
Guide Device ◽  
The Impact ◽  
Chain Drives

Particularly at the higher sprocket speeds, one of the main sources of noise and high-frequency vibration in a roller chain drive is the impact which occurs each time the driving sprocket collects a roller from the chain span. A method of guiding the chain so as to virtually eliminate these impacts is described. Details are given of experimental tests in which a simply-constructed guide device greatly reduced the amplitude of the high-frequency vibration of a drive, and produced a very significant lowering of the noise level.

Experimental investigation of isothermal and reacting flow characteristics downstream of axisymmetric bluff body stabilizers under stratified or fully premixed inlet mixture conditions

2020 ◽  
Author(s):  
Γεώργιος Πατεράκης
Keyword(s):  
Experimental Investigation ◽  
Turbulent Flow ◽  
Bluff Body ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Wide Range ◽  
Flow Features ◽  
Air Mixing ◽  
The Impact ◽  
Stratified Flames

The current work describes an experimental investigation of isothermal and turbulent reacting flow field characteristics downstream of axisymmetric bluff body stabilizers under a variety of inlet mixture conditions. Fully premixed and stratified flames established downstream of this double cavity premixer/burner configuration were measured and assessed under lean and ultra-lean operating conditions. The aim of this thesis was to further comprehend the impact of stratifying the inlet fuelair mixture on the reacting wake characteristics for a range of practical stabilizers under a variety of inlet fuel-air settings. In the first part of this thesis, the isothermal mean and turbulent flow features downstream of a variety of axisymmetric baffles was initially examined. The effect of different shapes, (cone or disk), blockage ratios, (0.23 and 0.48), and rim thicknesses of these baffles was assessed. The variations of the recirculation zones, back flow velocity magnitude, annular jet ejection angles, wake development, entrainment efficiency, as well as several turbulent flow features were obtained, evaluated and appraised. Next, a comparative examination of the counterpart turbulent cold fuel-air mixing performance and characteristics of stratified against fully-premixed operation was performed for a wide range of baffle geometries and inlet mixture conditions. Scalar mixing and entrainment properties were investigated at the exit plane, at the bluff body annular shear layer, at the reattachment region and along the developing wake were investigated. These isothermal studies provided the necessary background information for clarifying the combustion properties and interpreting the trends in the counterpart turbulent reacting fields. Subsequently, for selected bluff bodies, flame structures and behavior for operation with a variety of reacting conditions were demonstrated. The effect of inlet fuel-air mixture settings, fuel type and bluff body geometry on wake development, flame shape, anchoring and structure, temperatures and combustion efficiencies, over lean and close to blow-off conditions, was presented and analyzed. For the obtained measurements infrared radiation, particle image velocimetry, laser doppler velocimetry, chemiluminescence imaging set-ups, together with Fouriertransform infrared spectroscopy, thermocouples and global emission analyzer instrumentation was employed. This helped to delineate a number of factors that affectcold flow fuel-air mixing, flame anchoring topologies, wake structure development and overall burner performance. The presented data will also significantly assist the validation of computational methodologies for combusting flows and the development of turbulence-chemistry interaction models.

Numerical Simulation on Dynamic Behavior of Intermittent Roller Chain Drives

2012 ◽  
Vol 155-156 ◽  
pp. 535-539 ◽  
Author(s):  
Li Xin Xu ◽  
Yong Gang Li
Keyword(s):  
Numerical Simulation ◽  
Dynamic Behavior ◽  
Simulation Analysis ◽  
Longitudinal Vibration ◽  
Three Dimension ◽  
Chain Drive ◽  
Rigid Body Dynamic ◽  
Analysis And Design ◽  
Roller Chain ◽  
Chain Drives

A detailed numerical simulation analysis on the dynamic response of intermittent roller chain drive has been carried out in this study. Instead of using analytical method, three dimension solid modeling software and multi-rigid body dynamic analysis software are utilized for modeling and simulating the dynamic behavior of chain drive. The longitudinal vibration response of the chain links is concentrated on, which aims to reveal the dynamic characteristics of the intermittent chain drive under varying motion laws such as the modified sinusoid (MS), the modified constant velocity (MCV) and the unsymmetrical modified trapezoid (UMT). The simulation results can enable designers to require information on the analysis and design of mechanisms with the intermittent roller chain drives.

Toward a More Exact Kinematics of Roller Chain Drives

1988 ◽  
Vol 110 (3) ◽  
pp. 269-275 ◽  
Author(s):  
C.-K. Chen ◽  
F. Freudenstein
Keyword(s):  
Impact Velocity ◽  
Kinematic Analysis ◽  
Design Stage ◽  
Chain Drive ◽  
Slow Speed ◽  
Roller Chain ◽  
Remarkable Degree ◽  
Chain Drives ◽  
Center Distance

A kinematic analysis has been developed for the motion of roller chain drives, which is exact for relatively slow-speed chain drives with negligible wear. The results shed new light on chordal or polygonal action, and the associated impact velocity and motion fluctuation of the chain drive. The results have also revealed the existence of a remarkable degree of sensitivity of chain performance with respect to center distance including discontinuities in the motion derivatives. This in turn provides a new opportunity for the optimization of chain drives by optimizing center distance both in the design stage, as well as during installation and maintenance.

Dynamics of High Speed Roller Chain Drives

1995 ◽  
Author(s):  
Peter Fritz ◽  
Friedrich Pfeiffer
Keyword(s):  
High Speed ◽  
Contact Forces ◽  
System Structure ◽  
Unilateral Constraints ◽  
Roller Chain ◽  
Contact Configuration ◽  
Nonlinear Force ◽  
A Chain ◽  
The Impact ◽  
Chain Drives

Abstract This paper deals with roller chain drives applied in combustion engines. In order to find characteristics for an optimal design, all components of a chain drive are taken into account. For a detailed analysis of the chain strand vibrations and the contact configurations each chain link, sprocket and guide is treated as a separate body. A nonlinear force element describes the joint forces, including elasticity, damping, backlash and oil-displacement. To determine real contact forces between a link and a sprocket or a guide, the exact contour and the mutual dependence of the contacts are considered. The impact of one link may influence the other links in such a manner that their contact configuration may change. In the mechanical model these contacts are represented by unilateral constraints. Applying the formulation of the linear complementarities including additional inequality conditions, the determination of a valid contact configuration after a change in the system structure is simplified.

An experimental investigation of the initial force of impact on a sphere striking a liquid surface

1981 ◽  
Vol 108 ◽  
pp. 133-146 ◽  
Author(s):  
M. Moghisi ◽  
P. T. Squire
Keyword(s):  
Experimental Investigation ◽  
Drag Coefficient ◽  
Liquid Surface ◽  
Impact Force ◽  
Theoretical Calculations ◽  
Square Root ◽  
Homogeneous Fluid ◽  
Initial Force ◽  
The Impact ◽  
Good Agreement

Detailed experimental results are presented for the initial impact force on a sphere striking a horizontal liquid surface vertically at speeds in the range 1-3 m s−1. Results are discussed in terms of an impact drag coefficient. Liquids having viscosities in the range 10−3−102 Pa s have been studied. For low viscosities the results have been compared with the theoretical calculations of Shiffman & Spencer. Good agreement has been found in most respects; in particular the impact force varies as the square root of the depth for depths less than a tenth of the radius. The impact drag coefficient has also been studied through the transition from inertia to viscosity-dominated conditions. The variation of the impact drag coefficient is presented as a function of Reynolds number, and its variation in the range 5 × 10−2 < Re < 5 × 103 is shown to resemble that of a fully immersed sphere moving steadily in a homogeneous fluid.

On the Impact Intensity of Vibrating Axially Moving Roller Chains

1992 ◽  
Vol 114 (3) ◽  
pp. 397-403 ◽  
Author(s):  
K. W. Wang ◽  
S. P. Liu ◽  
S. I. Hayek ◽  
F. H. K. Chen
Keyword(s):  
Chain Structure ◽  
Momentum Balance ◽  
System Response ◽  
Roller Chain ◽  
Impulse Function ◽  
Static Approach ◽  
Axially Moving ◽  
Local Impacts ◽  
The Impact ◽  
Chain Drives

Experimental observation has shown that the most significant noise source in roller chain drives is from the impacts between the chain and the sprocket during their meshing process. Despite its importance, studies have not been made to thoroughly analyze the chain/sprocket impact dynamics and their interaction with the vibrating, axially moving chain structure. This paper presents a novel analysis which integrates the local meshing phenomena with the global system. An axially moving chain interacting with local impacts has been modelled and the momentum balance method is employed to derive the impulse function. A study is carried out to quantify the intensity of subsequent impacts. It is found that the impact intensity is significantly affected by the vibration characteristics and response of the moving chain, and vice versa. The classical quasi-static approach will create errors in predicting the impulse magnitude and system response. Meshing frequencies that will cause maximum and minimum impulses are analytically predicted. This fundamental investigation provides new insight into roller chain dynamics, which is an essential step toward the design of quiet chain drives.

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