Sprocket Wheel Research Articles

Tension Characteristics Analysis of Scraper Chain of Heavy‐Duty Scraper Conveyor with Time‐Varying Loads

With the intensification and large scale of coal mining, scraper conveyors are developing towards high power, large volume, long haul distance, and high reliability. It is more and more important to obtain the dynamic tension of the scraper chain with time‐varying loads. The purpose of this paper is to obtain the dynamic tension of scraper chains of the scraper conveyor with time‐varying loads. First, according to the structural characteristics and working environment of the scraper conveyor and the polygon effect of the sprocket, the scraper conveyor dynamic model under the action of the time‐varying loads is established by the finite unit method. Second, the load variation rule of the bearing section is explored when the scraper conveyor and shearer work together. Furthermore, the element resistance of each discrete element, the stiffness coefficient of the scraper chain, and the influence of polygonal effect of sprocket wheel are analyzed. And then, the dynamic tension of the scraper chain is obtained by the Hilber–Hughes–Taylor (HHT) method. Finally, the validity of the scraper conveyor dynamic model is verified by the example analysis and field measurement experiment. Due to the influence of heavy starting, the maximum tension of the scraper chain during the starting process is 751.6 kN, which is 12.25% higher than the tension with smooth running (669.6 kN). During the startup stage, significant impacts occur on both motors and scraper chains which may lead to damage. To protect these components effectively, control strategies such as “soft start” or no‐load start hold crucial engineering significance in achieving reliable operation of the scraper conveyor. The obtained results can provide a theoretical basis for the reliability evaluation and parameter optimization of the scraper conveyor.

The Amazing Kinematics of a Chain Passing over a Sprocket Wheel

The Amazing Kinematics of a Chain Passing over a Sprocket Wheel

CAUSAL ANALYSIS AND SOLUTION OF THE FAILURE OF SPROCKET DRIVERS IN A CLINKER SCRAPER CONVEYOR

This study discusses the causal analysis and solution of the teeth failure in sprocket drivers in a clinker scraper conveyor of a cement plant. The failure consisted of the progressive surfacing shape loss of the teeth, progressively deteriorated to the operating conditions of the system, causing dynamic loads, which affected the mechanical transmission and the conveyor general performance. The assessment includes an analysis of the sprocket material and calculations of the stress fields in the teeth surface. The results show the failure is the result of using a sprocket material with high-abrasive resistance, but with yield strength lower than required for operating conditions. This failure can be addressed by replacing the entire sprocket that results in significant downtime and economic losses. The main contribution of this study is developing a solution based on the local quality principle to repair and prevent the failure without removing the sprocket. Furthermore, the analysis considers the surface forces resulting from the high friction coefficient caused by the lack of lubrication, resulting in stress values higher than the fluence limit of the teeth material. Therefore, the solution proposed is manufacturing the teeth with a different material with higher strength and abrasion resistance to prevent failures by deformation. The proposed solution takes advantage of the damaged sprocket wheels available in the plant. The teeth manufactured are welded in a plate that is later bolted to the sprocket wheel, which was previously machined to remove the damaged teeth and prepare the surface to assemble the new teeth.

Fracture failure for the teeth of sprocket wheels in mineral conveying equipment

In this work, fracture failure for the teeth of sprocket wheels in a mineral conveying equipment was analyzed. The teeth fractured during the unloaded testing after the assembly of the sprocket structure. The evidence showed that failure of the sprocket tooth was a brittle fracture. It was caused by the rapid crack propagation from the inside defective region to the outer of the material under a combination action of the residual stress inside the material and the bending stress during the short-term operation. According to the analysis results, the initial region of the fracture was located at the areas of hydrogen flakes, which was the main reason for the fracture of the sprocket teeth.

Designing and Validation of a Sprocket Wheel for a Formula Student Vehicle

Designing and Validation of a Sprocket Wheel for a Formula Student Vehicle - written by Rohan Rai , Sharat Anand , Shayak Choudhary published on 2020/06/05 download full article with reference data and citations

Modeling and Analysis of Zenith based Passive Solar Tracking Mechanism

A novel gravity-based, power-free solar tracking mechanism is being developed to track the movement of the sun across day length. A compound parabolic collector having 3 parabolic segments is chosen due to its high intercept factor and suitability to the current tracking as compared to a cylindrical parabolic collector. Used to concentrate the incident solar radiation to the focal point, the Compound Parabolic Collector accumulates heat at the central coil, which is in turn used for process heating applications. The working of the tracking mechanism is studied to find the tracking loads in the east and the west sides of collector. We intend to simulate the tracking motion from the sunrise to sunset, in order to validate the empirical findings. The identified design variants are sprocket wheel diameter, suspension, solar collector’s weight, counter balance and loading on the shaft. The recommended diameter for the sprocket wheel and shaft is 2500mm and 50mm respectively.

Design and Optimization on Sprocket Wheel with Different Materials

Design and Optimization on Sprocket Wheel with Different Materials

Abrasive wear characteristics of 40Mn2 steel in simulated condition of sprocket wheel in crawler bulldozer walking system

The abrasive wear characteristics of 40Mn2 steel be studied in this paper. The rubber wheel abrasive wear tester be used for simulating the sprocket wheel working-conditions. The relationship between worn surface residual stress and wear rate was studied. Wear surface morphology and mechanism worn surface micro-structures are also shown in results. In addition, there are XRD pattern of the experimental abrasives, to better reveal the abrasive wear mechanisms. The results indicates that the larger the applied load and sliding speed is, the greater the wear rate will be. The content of hard phase in abrasive determine the wear rate. The main wear mechanisms of soil and coal in working-conditions are scratching and spalling, respectively. Spalling, chipping, scratching and pitting are the main wear mechanisms in sand working-condition. There are same trend of the wear rate and the worn surface residual stress with the wear time increasing. Intergranular carbides can decrease the wear resistance to some extent.

Hot forging process design of sprocket wheel and environmental effect analysis

Manufacturing industries have become increasingly conscious of energy wastage and environmental emissions. The energy consumption and environmental effect of each manufacturing process is different. This study aims to compare the environmental effects of the hot forging process and machining process for manufacturing sprocket wheels. It is important to design a preform when forging a sprocket wheel. The sprocket wheel tooth section is the weak point in folding, and an unfilling defect may occur. Therefore, preform and flash stopper shapes are critical design factors in the hot forging process for manufacturing sprocket wheels. Finite element analysis was used to design the preform, and analyze the deformation and effect of flash stopper in the hot forging process. The energy consumption for an actual product and for a product based on the analysis were compared to analyze the environmental effects. The results showed that the material loss and energy consumption were reduced in the developed hot forging process; this process is a green process with comparatively higher energy saving than the machining process.

Simulation study on speed control of permanent magnet direct-driven system for mining scraper conveyor

A simulation method of speed control based on the load characteristic of the permanent magnet direct-driven system is presented for mining scraper conveyor. Firstly, the mathematical model of permanent magnet synchronous motor (PMSM) is established based on the coordinate transformation theory. Subsequently, the closed loop speed controller of permanent magnet direct-driven systems is designed on the basis of sliding mode control theory and motor model. The chain characteristics of scraper conveyor are described by Kelvin-Vogit model, and the dynamic model of the overall scraper conveyor system is established with distinct element method. Then, according to the coupling relationship between the permanent magnet direct-driven system and the scraper conveyor, the simulation model of the scraper conveyor is established by using MATLAB/Simulink module. The simulation results demonstrate that the permanent magnet direct-driven system can realise smooth starting of the scraper conveyor, and the random load and polygonal sprocket wheel can influence the stability of speed control system.

Effect of processing parameters of laser on microstructure and properties of cladding 42CrMo steel

Due to the abrasion of sprocket wheel socket and high cost, the failure 42CrMo steel is remanufactured using the laser cladding technology with paraxial powder feed. The remanufacturing was carried out through an 8-kW CO2 laser device with rectangular spot of 3 × 24 mm and the self-developed Fe-based powder. The effect of processing parameters on macromorphology, microstructure, and microhardness of cladding layer and heat-affected zone (HAZ) was investigated. The results showed that the quality of cladding layer is improved with the increase of laser energy density (P/A). Under the same energy density, the quality of cladding layer is superior when decreasing the scanning speed. The microhardness of heat-affected zone which is 1.5–2.5 mm in width ranges from 210 to 450 HV. The HAZ is composed of completely quenched zone, incompletely quenched zone, and tempered zone. The microhardness of cladding layer which is approximately 1.8 mm in thickness is between 210 and 450 HV and is double even tripled as substrates. From the fusion line to surface, the microstructure of cladding layer is plane crystal, cellular crystal, and dendrite crystal, in turn. With the increase of laser energy density, the microhardness of HAZ and cladding layer increases; meanwhile, the width of HAZ shows a fluctuant rising trend. The microhardness of coatings was improved on account of the martensite, fine grains, solid solution, and precipitated phases. Especially, the latter two are decisive factors under the higher laser energy.

Needleless electrospinning using sprocket wheel disk spinneret

Needleless electrospinning is expected to produce nanofibers with a large productivity. In this study, a sprocket wheel disk was used as spinneret to electrospin nanofibers. The sprocket disk shows reliable electrospinning process. In comparison with the conventional disk spinneret, which has no sprocket on the edge, the sprocket wheel produced more uniform nanofibers with smaller fiber diameter. The electric field analysis results indicated that the sprocket wheel generates higher intensity of electric field.

Analysis of windlass sprocket wheel intensity

The multi-body dynamics model of windlass was established by RecurDyn and Pro/E in this paper, and the multi-body dynamics simulation was also conducted. According to the results of the multi-body dynamics simulation, structural static analysis on sprocket wheel in dangerous conditions were executed by ANSYS Workbench. The results showed that there are three bearing situations in the meshing transmission process of sprocket wheel and chain: Single tooth bearing, two tooth bearing and carrying equal contact force and two tooth bearing but one tooth contact force reaches the maximum value. The equivalent stress value at the contact position of sprocket wheel and chain exceeds the yield stress of the chain wheel material, but it does not cause damage to chain wheel. In addition to the contact location, the equivalent stress value of the remaining parts of sprocket wheel are in the allowable stress range of sprocket wheel material, comply with the requirement of strength design.

Experimental and simulation studies on a novel gravity based passive tracking system for a linear solar concentrating collector

A novel gravity based passive solar tracking mechanism; suitable to a linear solar concentrating collector has been conceptualized, developed, simulated, analyzed and tested experimentally. Attempt has been made to minimize the tracking load and error by controlling in dripping rate or filling rate of liquid in the gravity system. The identified key influencing design parameters in the proposed mechanism are sprocket wheel radius, spring stiffness and tracking radius. Large sprocket wheel, low stiff spring and small tracking radius minimizes the tracking loads. The recommended sprocket wheel radius and tracking wheel radius are 125 mm and 60 mm respectively. The simulation studies are validated with the experimental results. Practically obtained collector’s incidence angle is compared with the minimum required (theoretical) incidence and found a satisfactory match. The improvement in thermal efficiency of the collector with the proposed tracking mechanism has been highlighted by comparing the efficiency of intermittent tracking collector.

Design and analysis of a gravity-based passive tracking mechanism to a linear solar concentrating collector

A novel gravity-based power-free solar tracking mechanism has been developed to track a linear solar concentrating collector. Multireflector compound parabolic collectors having three parabolic segments and two flat surfaces is chosen due to its high intercept factor and suitability to the current tracking. The working of tracking mechanism is studied to find the tracking loads in the east and the west sides of collector. A generalized mathematical model is derived to simulate the tracking motion from the sunrise to sunset. The identified design variants are sprocket wheel diameter, spring stiffness, solar collector’s weight, counter balance, and tracking wheel radius. The spring length is derived from the constraints. To make a compact product, the tracking load has been minimized at large sprocket wheel, low stiff spring, lighter collector weight, and small radius of tracking. For a typical collector load of 50 kg, the designed tracking load is 50 kg with 620 mm spring length, 250 mm of sprocket wheel diameter and 60 mm tracking radius.

시뮬레이션을 통한 M/C용 공작물 자동교환장치의 설계

The objective of this study is to develop an automatic object changer unit to improve changing process problems existing in the conventional horizontal machining center. In order to perform this objective, an upward and downward traverse unit was designed. This unit consists of a motor, reducer, chain and sprocket wheel, and an upper and lower base. This automatic object changer unit performs a sliding contact motion in a purpose built and designed frame. Constraint conditions for the upward and downward traverse unit were first designed. Then, an operation mechanism was designed and introduced as the sum of the kinetic energy for the sprocket wheel and the upper and lower base and which was based on the moment of inertia, which is the kinetic energy of the converted upward and downward traverse unit in the side of the reducer. The paper covers the design of th e Automatic Pallet Changer for th e machining center.

Design and Experimental Study of a Mower Conditioner Drive System

According to the forage of mountain region harvesting requirements, a transmission of montanic mower conditioner was designed. The drive system was combined with automatic tension sprocket and double chain wheel of upper and lower crushers, firstly, to realize the automatic regulation and relative motion of two flattening roller, secondly, the power was passed to reel device and achieved forage feeding function; the off-center slider crank mechanism drove the horizontal header to realize the grass cutting function. Through the theoretical analysis and experimental study of the system working performance, applied comprehensive scoring method to obtain the optimal combination of working parameters: the cutting ration was3, the press roller circumferential speed was 4.5m/s, the reel speed ratio was 3. Measured with the optimal combination of operational parameters, the results showed that: the working stubble was 40mm, the recutting rate was 0.8%, the flattening ratio was 42.8% and the crushed grass loss rate was 2.3%, which could meet the demand of forage harvest operation.

Study on Simulation of the Chain Transmission Mechanism

The chain transmission’s feature, the main failure form of roller chain and the research for the simulation of the chain transmission mechanism are introduced. Taking the simulation of the chain transmission mechanism in feeding system of a mechanical equipment as the research object, the kinematical properties and the affecting factors are analysed in this paper. It adopts the advanced connection pair to establish relationship between the sprocket-wheel and rollers, and realistically simulates the kinematical characteristics of the chain transmission mechanism. It provides a reference for the optimization design of the structure of the chain and sprocket wheel, through the analysis on the moving velocity and acceleration curve of the chain. It also provides a basis for verifying whether the chain and sprocket-wheel meet the design requirements or not.

Optimal Design of Tooth Profile for Sprocket Wheel on No Arching Sintering Machine

Aimed at the instability factors of no arching sintering machine in the operation, their causes is analyzed, from the theoretical design, the composite tooth profile curve of sprocket wheel is optimized. Combined with the motion characteristics of the pallet car and the conditions required, by choosing proper motional parameters, a unified curve equation of tooth profile is gained. According to the actual size of the sprocket wheel, the two composite tooth shape of sprocket wheel before and after optimization is compared, and the velocity and acceleration characteristics of the composite tooth profile curve are analyzed. The results show that the optimized composite tooth profile curve of the sprocket wheel is more simple and reasonable, and can improve the engagement condition of the sprocket wheel and the pallet car, easy to manufacture, these provide a theoretical basis for the stability operation of no arching sintering machine.

The Discuss about the New Approach of the Structural Layout of Belt Type Sintering Machine

Existing sintering machine for controlling of arch camber is not ideal. The usual way is by means of the hydraulic system to balance the excess thrust what is caused arching. For this reason, the paper considers to change the structure layout of belt sintering machine ,so that eliminate the arch camber by itself. So improvement of process layout of 60㎡ sintering machine has been made, and thus deduced the expression and got the limen formula of the thrust force which the back sprocket wheel drive lower pallet cars. At the same time, through the analysis and compute got driving moment of lower pallet cars, which caused by four pallet cars from back sprocket wheel. According to equation of mechanical equilibrium to eliminate the arch of pallet cars, determine the suitable angle after sintering machine has been improved to solve the problem about arch pallet cars completely.