A method to determine the dynamic load distribution in a chain drive

Author(s):  
I Troedsson ◽  
L Vedmar

This paper presents a method to calculate the forces in a chain and, thus, the resulting load distribution along the sprockets in a chain transmission working at a moderate or high speed. When the chain drive is loaded, the rollers that contact the sprockets will move along the flanks to different height positions. There are mainly two different ways to determine the actual positions: to assume the positions or to use force equilibrium and to calculate the positions. To find the correct solution the geometry and the force equilibrium are used which will give each roller's position, along the flank. This method demands knowledge of all parts of the chain, even the slack part. Therefore it has been necessary to model both the connecting tight and the slack spans in which power between the two sprockets is transmitted. The gravitational force acting at the chain has been included in the complete model so that the position of the rollers and the forces in the links at the slack span can be calculated. The elastic deformation in the chain has also been included. The moment of inertia in the two sprockets and in the outer geometry has been taken into account, but not the inertia forces in the chain.

1999 ◽  
Vol 121 (3) ◽  
pp. 402-408 ◽  
Author(s):  
I. Troedsson ◽  
L. Vedmar

A model of how to calculate the load distribution for a chain drive is presented. In the model the complete standard geometry is used without any assumptions. The rollers which are in contact with the sprockets can move freely along the tooth flanks and their positions are given by force equilibrium. Since the positions of the rollers and thereby also the load distribution are dependent on the two connecting spans, these necessary tight and slack spans have been included in the model. The elastic deformation in the chain is included as well as the gravitational force.


1999 ◽  
Vol 123 (3) ◽  
pp. 395-401 ◽  
Author(s):  
I. Troedsson ◽  
L. Vedmar

A model is presented in which the oscillations, and the forces thus produced, in a chain drive, working at moderate and high speed, can be calculated. Since the outer system affects the result it has been necessary to include this in the model. The mass of the chain is included in the model and both the gravitational forces and the inertia forces in the chain are taken into account. The elasticity in the links is included. The sprockets are connected by two spans, both of which have to be included in the model to fulfill the equilibrium equations for the rollers in contact with the sprockets. The position of the chain is given by the geometric conditions as well as the equilibrium condition. On the slack side a chain tensioner is used to reduce the transverse oscillation, which occur at higher speeds.


2021 ◽  
Vol 4 (1) ◽  
pp. 29-35
Author(s):  
Nafisa Saidho’jaeva ◽  

The article deals with the calculation of the drive and chain transmission of the newly created mechanized drying plant for drying melon slices. The essence of the utility model: the machine contains a horizontal tunnel chamber, inside which is mounted a chain conveyor with driving and driven sprockets, load-carrying elements, the IR emitters with reflectors on top of the camera mounted electric air heater, fan, an annular heat exchanger equipped with inlet and outlet nozzles of the drying agent. On the branches of the conveyor chain, lodgments with folding clamps are mounted, on which load-bearing elements are fixed, which are used as wooden poles. The calculation of the drive and chain transmission of the drying plant conveyor was carried out according to the existing method according to the scheme shown in the figure. Thus, the main parameters of the drive and chain transmission parts of the mechanized chamber-chain drying plant for drying melon fruits were determined by calculation


2020 ◽  
Vol 10 (3) ◽  
pp. 1026 ◽  
Author(s):  
Zhong Tang ◽  
Xiyao Li ◽  
Xin Liu ◽  
Hui Ren ◽  
Biao Zhang

Although the individual threshing drum of a combine harvester was balanced on a dynamic balancing machine before it is assembled, there were still unbalances after multiple drums were assembled with the chain drive. In this paper, the double drums with a chain drive of a crawler combined harvester were selected as the research subject. The aim of this study was to develop a dynamic unbalance mode for grading chain drive double drums. Based on the dynamic unbalance characteristics of the main driven drum, the experimental research on the radial balance of the driven drum end face was carried out. It was known that the chain drive had a direct and obvious influence on the unbalanced phase of the drum. The unbalance of the drive load had an obvious effect on unbalanced amplitude of an active drum through the transfer characteristics of the chain drive. For the multi-stage transmission characteristics of a combine harvester, a step-by-step balanced grading chain drive double drum dynamic balancing method was practiced. Results showed that the unbalanced amplitude after balancing threshing drum I chain transmission mode of the combine harvester can be reduced by a maximum of 91%. Simultaneously, the unbalanced amplitude of threshing drum II can reduced by a maximum of 69.2%. The size and position of the wrap angle of the chain drive would directly affect the phase of the two equivalent unbalanced masses.


Author(s):  
N E Hollingworth ◽  
D A Hills

In a previous paper (1), the contact forces in a chain bearing during articulation were established. The present note describes the application of these results to the theoretical evaluation of efficiency for a conventional chain transmission using cranked link (or offset) type chain.


2014 ◽  
Vol 687-691 ◽  
pp. 523-526
Author(s):  
Lin Hong ◽  
Xiao Juan Li

Polygon effect is the inherent characteristics of chain drive system, and also the main factor which restricts the transmission performance of the system. In this article a structure related to a slide constraint chain drive is presented and optimized by means of MATLAB optimization toolbox. Based on polygon effect analysis, a compensation method is proposed and verified by trajectory simulation. Simulation results show that the compensation method can effectively reduce the polygon effect of chain drive and improve the transmission performance of the chain drive system.


2018 ◽  
Vol 8 (4) ◽  
pp. 37 ◽  
Author(s):  
Giovanna Turvani ◽  
Laura D’Alessandro ◽  
Marco Vacca

Among all “beyond CMOS” solutions currently under investigation, nanomagnetic logic (NML) technology is considered to be one of the most promising. In this technology, nanoscale magnets are rectangularly shaped and are characterized by the intrinsic capability of enabling logic and memory functions in the same device. The design of logic architectures is accomplished by the use of a clocking mechanism that is needed to properly propagate information. Previous works demonstrated that the magneto-elastic effect can be exploited to implement the clocking mechanism by altering the magnetization of magnets. With this paper, we present a novel clocking mechanism enabling the independent control of each single nanodevice exploiting the magneto-elastic effect and enabling high-speed NML circuits. We prove the effectiveness of this approach by performing several micromagnetic simulations. We characterized a chain of nanomagnets in different conditions (e.g., different distance among cells, different electrical fields, and different magnet geometries). This solution improves NML, the reliability of circuits, the fabrication process, and the operating frequency of circuits while keeping the energy consumption at an extremely low level.


Author(s):  
Peter Racioppo ◽  
Wael Saab ◽  
Pinhas Ben-Tzvi

This paper presents the design and analysis of an underactuated, cable driven mechanism for use in a modular robotic snake. The proposed mechanism is composed of a chain of rigid links that rotate on parallel revolute joints and are actuated by antagonistic cable pairs and a multi-radius pulley. This design aims to minimize the cross sectional area of cable actuated robotic snakes and eliminate undesirable nonlinearities in cable displacements. A distinctive feature of this underactuated mechanism is that it allows planar serpentine locomotion to be accomplished with only two modular units, improving the snake’s ability to conform to desired curvature profiles and minimizing the control complexity involved in snake locomotion. First, the detailed mechanism and cable routing scheme are presented, after which the kinematics and dynamics of the system are derived and a comparative analysis of cable routing schemes is performed, to assist with design synthesis and control. The moment of inertia of the mechanism is modeled, for future use in the implementation of three-dimensional modes of snake motion. Finally, a planar locomotion strategy for snake robots is devised, demonstrated in simulation, and compared with previous studies.


2018 ◽  
Vol 24 (3) ◽  
pp. 83-90 ◽  
Author(s):  
A. Yu. Mushkin ◽  
D. G. Naumov ◽  
E. Yu. Umenushkina

Purpose of the study— to study impact of hemi-vertebrae extirpation technique in mono-segmental reconstructionon the surgical trauma.Material and Methods.34 patients underwent 36 mono-segmental extirpations of hemi-vertebrae followed by aposterior fixation during a single center four years cohort study. Mean age of children at the moment of procedure was 4 years and 3 months (min — 1 year, max — 14 years). The authors studied impact of pathology level, surgical approach, type of bony structures removal technique and age of the patients on the time of procedure and volume of blood loss. Results.Extirpation of thoracic hemi-vertebrae was characterized by a lengthier procedure and greater blood lossin contrast to lumbar hemi-vertebrae. Patients were divided into three groups depending on extirpation technique: 1)  extirpation from two approaches using a high-speed burr; 2) from a single dorsal approach using the same extirpation technique; 3) from dorsal approach using ultrasonic bone scalpel. Surgery time was 208±72 min in the first group, 187±54 min in the second group, and 170±30 min in the third group; blood loss volume was 181±39, 181±53, 132±73 ml respectively in the groups, or 11.5±4.3%, 9.4±2.8% and 9.6±5.2% of total blood volume, respectively.Conclusion.Surgical approach and hemi-vertebrae extirpation technique in children have a varying impact onsurgery time and intraoperative blood loss, and the least values were reported for posterior approach using ultrasonic bone scalpel.


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