Gear Mechanism Research Articles

Rattle Dynamic Model and Vibration Behaviors of Noncircular Face Gear

Abstract Noncircular face gear (NFG) is a new type of variable transmission ratio gear mechanism. Based on nonlinear dynamic theory of gear, the rattling behavior of the NFG under multifrequency excitation was studied. The generalized transmission ratio function of the NFG with closed pitch curve was constructed by Fourier series. The nonlinear relative displacement between teeth was described by an analytical expression during the process of time-varying transmission. Considering the factors of time-varying instantaneous center, meshing stiffness, transmission error, and backlash, a nonlinear dynamic model of the gear was established with the rotational angle as the independent variable. The dynamical responses were calculated by Runge–Kutta method to analyze the effects of the input speed, load torque, transmission ratio coefficient, and error on rattling behaviors. The results show that under the action of combined excitation of time-varying instantaneous center and meshing stiffness, the rattle of noncircular gear is more likely to occur. As the increase in input speed, error, and range of transmission ratio variation or the decrease of load, the NFG appears no rattling, unilateral, and bilateral rattle successively and the rattling intensity increases accordingly. The rattling threshold speed can be improved by increasing the accuracy and load of gear or decreasing the range of the transmission ratio.

The MEKANISASI BAGAN TANCAP MENGGUNAKAN ROLLER PENGANGKAT JARING DI PANGANDARAN, JAWA BARAT

Pangandaran is located in the southern coast of the Java Island. Some of Pangandaran fishers operate lift net (bagan) to catch fish and shrimp. During hauling process, the net is lifted manually using a roller that potentially harm the fishers. The purpose of this study was to design a mechanical roller that applicable for lift net. The analysis of design requirement, such as calculation of torque, horse power, and reduction power with gear mechanism for operating the roller were applied in this research. The results showed that the net lifting operation required 4.8 HP or 3.6 KW of diesel engine to power a hydraulic pump. For the maximum load, when the net is fully loaded with fish, the operation required 67.91 HP or 50.64 KW. It means power from the diesel motor was not enough to support at maximum load. Therefore, a gear mechanism with a ratio of 1:14 was applied. However, this method reduces the angular speed of the gear which leads to reduction on net pulling speed.
 Keywords: Lift net, hydraulic, horse power, power, and lifnet roller

Principle and Analysis of Radial-Force-Based Swirling Actuator for Low-Speed High-Torque Applications

This article proposes a swirling actuator that uses the electromagnetic radial force and mechanical gears to generate rotational torque. The proposed actuator generates a rotating radial force between an inner stator and a swirler. The gears on the swirler and outer rotor convert the circular motion of the swirler to low-speed rotor rotation. Thus, the proposed actuator is aimed at low-speed high-torque applications. In this study, the air-gap radial flux density and electromagnetic radial force are investigated analytically and verified through finite-element analysis. The static radial force and output torque are measured in a prototype of the actuator. The system efficiency and the gear efficiency are evaluated. A peak torque density of 27 Nm/L with a small volume of 0.16 L is realized in the prototype.

Rapid prototyping method for replacing non-circular gears

The paper presents a modern method of obtaining non-circular gearwheels from by means of additive technologies. Such a method is useful in case of wear or failure of a mechanical gear which has in its composition such non-circular metal gearwheels in the case of technical systems that must ensure continuous operation. With the help of the FDM technology (Fused Deposition Modeling) it will be created a model of the non-circular gearwheel that will constitute casting model for future gear, or they can even be used as functional gears if a suitable material and a precise execution technology with optimal printing conditions are considered.

Weed Plucking Robot with Wireless Technologies

Abstract: The main function of this robot is to remove the unwanted tiny plants or grass from the main crop, this system is very useful for farmer which avoids lot of manual work. Plucking weeds manually is very painful activity and also consumes lot of time and therefore this mechanism is designed. Since it is a prototype module, basic version of grass or tiny weeds plucking mechanism is designed with spur gears. The moving mechanism is constructed with motorized wheels, for this purpose 30RPM motors are used. The mechanism is designed to move in all directions including reverse direction. The plucking mechanism designed with spur gears is attached with another motor shaft. Two spur gears are used and are meshed with each other, when the vehicle is moving and when the gears are rolling, the grass or tiny weeds will be removed by the gear mechanism. The demo module is constructed with small spur gears, with this the basic concept can be proved and it is not a full fledged mechanism. With the help of a remote control unit constructed with 12E, 12D chips & RF transmitter, entire machine can be controlled. H Bridge IC is used to drive the wheel drive motors through remote and weed picking mechanism must be activated manually through third DC motor. Moving mechanism is controlled through 2 DC motors and is controlled independently by which mechanism will be moved in all directions. 12V, 1Ah Rechargeable battery is used to run the entire system and this battery can be charged through ac adapter. The remote is constructed using four keys to move the robot forward, reverse, right and left directions. By pressing any control key in the remote unit, the encoder chip generates proportionate digital code, which is fed to the RF transmitter for transmitting the data. In the receiver, the received data will be decoded by the 12D IC and based on this code this chip enables the H Bridge IC by which the corresponding motor rotates in one direction. Likewise both DC motors will be controlled independently according to the command code received by the communication system.

A Study on MG-PMSM for High Torque Density of 45 kW–Class Tram Driving System

This paper reports the design of a magnetic-geared permanent magnet synchronous motor (MG-PMSM) for a 45 kW tram traction system based on high torque density. In the case of the existing tram driving system, due to mechanical reduction gear and induction motor, it causes power transmission loss, low efficiency, and difficulty in lightweight. To solve this problem, research on the MG-PMSM, which combines a contactless magnetic gear with a high-power-density PMSM, is being actively conducted. This motor has a double rotor structure, and the inner rotor, including permanent magnet, and the outer rotor composed of pole-pieces rotate at different mechanical speeds. However, it is hard to design a tram driving system with a high torque density within limited conditions, because only one rotor in MG-PMSM is used as an output. In addition, there is no study conducted from basic design to final design, including gear ratio and topology selection in MG-PMSM for tram. Therefore, this paper presents the design process of MG-PMSM with high torque density to be applied to the 45 kW–class tram driving system. After designing the magnetic gear part that increases torque and efficiency by selecting an appropriate topologies-and-gear ratio that meets the constraints, the final finite elements method (FEM) model and electromagnetic field analysis results were derived by considering the number of poles and the number of slots. Through this, we confirmed that it is superior in output characteristics compared to the existing induction motor + mechanical gear.

Study on mesh stiffness and sensitivity analysis of planetary gear system considering the deformation effect of carrier and bearing

The mesh stiffness characteristics and tooth root crack propagation of planetary gear system not only have an important impact on its transmission error, but further affect its vibration and noise level and the bearing capacity of gearbox. It is of great theoretical and engineering significance to study them comprehensively. First, the stiffness-damping model of the planetary gear mechanism is obtained by simplification, and the meshing phase relationships between the studied gear pairs are gotten by theoretical calculation. Then, through the FE modeling, the time-varying mesh stiffness of the sun-planet substructure, ring-planet substructure, and single-branch sun-planet-ring substructure are calculated respectively, and the influence of carrier and bearing flexibility on mesh stiffness is further studied. The mesh stiffness prediction method of the single-branch substructure is proposed and verified, and the overall mesh stiffness of the planetary gear system is predicted and analyzed. Finally, a sensitivity analysis model is established to study the effect of crack propagation at the root of sun and ring on mesh stiffness, capacity, and NVH features. The results show that the sun tooth root crack has a more significant impact on the mean stiffness and bearing capacity, and the ring tooth root crack has a more dramatic influence on the peak-to-peak stiffness and the vibration and noise characteristics of the gear system.

Systematic design of snake arm maintainer in nuclear industry

This paper develops a remote handling system with a Snake Arm Maintainer (SAM) as the end effector, which aims to meet the maintenance needs of various narrow working spaces of the Chinese Fusion Engineering Test Reactor (CFETR). The multi-joint snake-arm is designed with the principle of layered drive to realie the angle synchronisation of adjacent joints, which reduces the complexity of the drive control system, and reduces the volume and weight while ensuring a high spatial curvature. The drive box is connected to the Multi-Purpose Overload Robot (CMOR) through a quick-change connector. The worm gear mechanism realies the reverse folding of the SAM and close to the CMOR, enabling access to the narrow vacuum chamber. Two working methods of SAM are designed based on trajectory planning and trajectory tracking. Finally, based on the actual environment of the CFETR vacuum chamber, simulation experiments were carried out on the rationality of the structural design of the SAM and the correctness of the working methods, which verified the feasibility of working in a narrow vacuum chamber.

Effect of reversing duration time and commutation meshing state on the elastohydrodynamic lubrication of reciprocating spur gear rack

AbstractReciprocating spur gear rack is prone to lubrication failure near the reversing dead center position. Ree‐Eyring lubrication fluid, multigrid method and multigrid integral method were used to calculate the pressure profile, film thickness and oil temperature rise. Compared with linear motion, the process of reciprocating commutative movement is more complicated and the lubrication state are more unstable. The effects of different reversing duration time and commutation meshing state on lubricant film were analysed. The results show that, the oil thickness during the gear reversing process is significantly reduced. While shortening the reversing time can improve the lubricating film thickness, it causes the instantaneous oil temperature to rise. Therefore, the gear tooth damage caused by high temperature can be avoided by prolonging the reversing duration time properly. The longer the reversing duration time, the minimum value of central film thickness and central pressure is closer to the meshing outlet area. No matter what the reversing time change, the minimum lubrication film thickness is in the reversing dead center position. So the reversing dead center is still the dangerous point for the lubrication failure of the spur gear rack mechanism. When the reversing dead center is in the leading tooth of double‐tooth meshing, the gear has the largest film thickness and the largest contact area. In addition, the synthetic radius of curvature and entrainment velocity become larger so the lubrication conditions have been improved. The results provide the theoretical basis and guidance for the reasonable design of the spur gear rack and the improvement of its lubricating performance.

Augmenting effectiveness of geared turbofan engines by dual stage radial blisks

PurposeThis study aims to propose a novel configuration for turbofan engine inlets to increase the overall effectiveness of the engine.Design/methodology/approachConventional fan has been split radially into two blisk stages, namely, core blisk and bypass blisk. The two blisks are driven by a common shaft but rotate at two different revolutions per minutes (RPMs) on the same plane of rotation simultaneously through a planetary gear mechanism. To avoid any mechanical contact between the two stages, a minimum optimum distance is kept between them.FindingsAn apt reduction ratio of planetary gears allows the bypass blisk to rotate at a lower RPM. Thus, unlike conventional geared single fan configuration, transonic speed at the blade’s tip is prevented without decreasing the core stage’s RPM. Consequently, wave drag is eradicated without compromising the engine's core performance as surplus air can always be supplied to it. Compressor stall and surge can also be significantly reduced.Research limitations/implicationsThe concept is at its infancy. Extensive iterations and experimentations are required before implementing it practically.Practical implicationsThe configuration fulfils to conceive a practical and industrially scalable method to extract better performance from existing engine architecture with minimal changes while reducing noise and emissions, meeting the short-term emission and noise goals unless electric or hydrogen-powered flight fully matured.Social implicationsThe present concept reduces engine noise and thereby helps in reduction of airport noise pollution. This concept also helps in reducing global warming by reducing emissions.Originality/valueThe paper presents a novel configuration for a turbofan engine’s inlet fan and discusses its engineering implications and initial feasibility in detail.

Optimization Design for the Planetary Gear Train of an Electric Vehicle under Uncertainties

The planetary gear train is often used as the main device for decelerating and increasing the torque of the drive motor of electric vehicles. Considering the lightweight requirement and existing uncertainty in structural design, a multi-objective uncertainty optimization design (MUOD) framework is developed for the planetary gear train of the electric vehicle in this study. The volume and transmission efficiency of the planetary gear train are taken into consideration as optimization objectives. The manufacturing size, material, and load input of the planetary gear train are considered as uncertainties. An approximate direct decoupling model, based on subinterval Taylor expansion, is applied to evaluate the propagation of uncertainties. To improve the convergence ability of the multi-objective evolutionary algorithm, the improved non-dominated sorting genetic algorithm II (NSGA-II) is designed by using chaotic and adaptive strategies. The improved NSGA-II has better convergence efficiency than classical NSGA-II and multi-objective particle swarm optimization (MOPSO). In addition, the multi-criteria decision making (MCDM) method is applied to choose the most satisfactory solution in Pareto sets from the multi-objective evolutionary algorithm. Compared with the multi-objective deterministic optimization design (MDOD), the proposed MUOD framework has better reliability than MDOD under different uncertainty cases. This MUOD method enables further guidance pertaining to the uncertainty optimization design of transportation equipment, containing gear reduction mechanisms, in order to reduce the failure risk.

Building of Inmoov Robotic Arm for Performing Various Operations

Abstract: ‘Automation is the key in reducing the repetitive and banal tasks of everyday life’, the oft-quoted aphorism best portrays our effort at making a humanoid hand for tasks that require dexterity of fingers in situations where time and effort are of importance. The cost of human labor, quality of processes or products, time, and safety make this project a need of the hour. The research paper showcases our efforts of making a humanoid robotic arm. The body of the arm is composed of 3D printed parts. Servo Motors with nylon strings were used to control the fingers and the wrist. InMoov Nervo Board was used to control the servos. Worm Gear Mechanism was implemented to control the bicep movement and Worm Wheel is used for shoulder rotation. Machines can perform a wide range of functions without a considerable amount of human intervention. The future scope of Robotics and Automation would be to make a diverse and positive impact in industrial as well as research applications. Keywords: 3D Print, Build Challenges, Electronics, Humanoid, Inmoov, MyRobotLab, Robotic Arm, Robotics

Simulation on coupling effects between surface wear and fatigue in spur gear

A surface wear prediction method is used to determine the wear rate of the tooth surface. This method employs the Archard’s wear model together with the gear contact mechanics model. An equivalent calculation model based on Hertzian contact theory and fracture mechanics is used to investigate crack initiation and crack propagation. The virtual crack extension (VCE) method is employed to analyze the propagation process from the initial crack to occurrences of tooth surface pitting. A life prediction method on the wear-fatigue coupling is developed. The crack propagation process and pit shapes are determined by the iterative analysis. The relationship between service life and the remaining distance from the crack tips to the tooth surface is determined. The damage mechanism of wear-fatigue coupling is explored. The results of the comparative analysis show that the wear of tooth surface affects the cracks propagation characteristics, reduces the service life and even can change the failure mode. The simulated pit shapes and crack propagation process are in good agreement with the results of other literature. The analysis method of wear-fatigue coupling damage can well simulate the damage process and predict service life in spur gear.

Cardiac Patch Transplantation Instruments for Robotic Minimally Invasive Cardiac Surgery: Initial Proof-of-concept Designs and Surgery in a Porcine Cadaver.

Background: Damaged cardiac tissues could potentially be regenerated by transplanting bioengineered cardiac patches to the heart surface. To be fully paradigm-shifting, such patches may need to be transplanted using minimally invasive robotic cardiac surgery (not only traditional open surgery). Here, we present novel robotic designs, initial prototyping and a new surgical operation for instruments to transplant patches via robotic minimally invasive heart surgery. Methods: Robotic surgical instruments and automated control systems were designed, tested with simulation software and prototyped. Surgical proof-of-concept testing was performed on a pig cadaver. Results: Three robotic instrument designs were developed. The first (called “Claw” for the claw-like patch holder at the tip) operates on a rack and pinion mechanism. The second design (“Shell-Beak”) uses adjustable folding plates and rods with a bevel gear mechanism. The third (“HeartStamp”) utilizes a stamp platform protruding through an adjustable ring. For the HeartStamp, rods run through a cylindrical structure designed to fit a uniportal Video-Assisted Thorascopic Surgery (VATS) surgical port. Designed to work with or without a sterile sheath, the patch is pushed out by the stamp platform as it protrudes. Two instrument robotic control systems were designed, simulated in silico and one of these underwent early ‘sizing and learning’ prototyping as a proof-of-concept. To reflect real surgical conditions, surgery was run “live” and reported exactly (as-it-happened). We successfully picked up, transferred and released a patch onto the heart using the HeartStamp in a pig cadaver model. Conclusion: These world-first designs, early prototypes and a novel surgical operation pave the way for robotic instruments for automated keyhole patch transplantation to the heart. Our novel approach is presented for others to build upon free from restrictions or cost—potentially a significant moment in myocardial regeneration surgery which may open a therapeutic avenue for patients unfit for traditional open surgery.

Design and experimental study of a planetary gearing mechanism based on twice unequal amplitude transmission ratio

To obtain the optimal seedling taking trajectory, this study proposed the adjustment of the total transmission ratio curve by using human-computer interaction. On the basis of this design method, a planetary non-circular gear mechanism was designed that can realize the twice unequal amplitude transmission ratio to meet the seedling harvesting requirements. The cubic non-uniform B-spline curve was used to fit the twice unequal amplitude transmission ratio curve, and the transmission ratio was freely distributed in two levels. The seedling pick-up mechanism was designed by controlling the seedling taking track and the corresponding attitude directly through the local section of the total transmission ratio, and the gear pitch curve was directly controlled by the transmission ratio. The kinematics model of the seedling pick-up mechanism was also established. Furthermore, the influence of the total transmission ratio on the seedling picking track, the ratio of the wave crest to the amplitude, and the mechanism parameters were discussed. A human-computer interactive optimization software was developed using Matlab, and a set of optimal parameters for the seedling pick-up mechanism was obtained to meet the transplanting requirements. By using the Adams software, the virtual prototype simulation of the seedling pick-up mechanism was completed, and the idle experiment for the track and attitude of the prototype was conducted through high-speed camera technology. The theoretical, simulated, and experimental trajectories were consistent with each other. Results revealed that the success rate of the seedling picking exceeded 90% when the rotation speeds were 40 r/min, 50 r/min, and 60 r/min, and the qualified rate of the matrix decreased with the increase in rotating speed. Moreover, the number of damaged plants increased with the increase in rotating speed. The experimental results showed that the seedling pick-up mechanism designed using the proposed method demonstrated a good effect and met the required seedling picking performance. Keywords: seedling pick-up mechanism, second unequal amplitude, planetary gear train, seedling picking experiment DOI: 10.25165/j.ijabe.20221501.6168 Citation: Liu J G, Yu G H, Tong Z P, Hua Y. Design and experimental study of a planetary gearing mechanism based on twice unequal amplitude transmission ratio. Int J Agric & Biol Eng, 2022; 15(1): 155–163.

ПРОЕКТНЫЙ РАСЧЕТ ЗУБЧАТОЙ ПЕРЕДАЧИ ГРУЗОВОГО ЭЛЕКТРОВОЗА С ОПТИМАЛЬНЫМИ ПАРАМЕТРАМИ КОРРИГИРОВАНИЯ

In result of the study the authors have established that mistakes in design a gearwheel are among main reasons that lead to a failure of a gearwheel for the 2ES6 freight electric locomotive. In order to increase life of the gearwheel they suggest a method for its redesign with adjustment of offset coefficients. The authors have developed a cylindrical involute helical gearwheel. With the use of modeling in the «Shafts and mechanical gears» application within the framework of the KOMPAS-3D system the authors have got strength and geometrical parameters of the redesigned gearwheel that meets all reliability requirements. Moreover, they have carried out a durability calculation that has confirmed correctness of gained values. As a result, the use of the developed model with optimal parameters of correlation adjustment will contribute to a decrease of a number of traction gearbox failures.

DESIGN AND LAYOUT OF AN ELECTRIC MOBILE VEHICLE FOR FARMING

Currently, there is an active use of electric transport, including farms, in order to perform technological processes in premises for keeping animals and growing plants. In this regard, there is a need to improve its technical characteristics, increase the traction force, which serves as the most important physical quantity in an electric vehicle. (Research purpose) The research purpose is developing a chassis and main components of the vehicle, choose a traction electric motor of a mobile vehicle with an electric drive. (Materials and methods) An analysis of manual transmission switching in electric vehicles was performed. The article presents the layout of the electric tractor chassis. (Results and discussion) The main components of an electric vehicle (mobile vehicle) are: chassis; traction battery; control charger; electric drive, including multi-speed gearboxes. The use of a gearbox allows you to expand the range of applications of the vehicle. The article presents the type and voltage of the battery to increase the service life of the traction battery. (Conclusions) The chassis and main components of the vehicle were designed. A traction electric motor of a mobile vehicle was chosen. With the use of the proposed complex of the main components of an electric mobile vehicle, it becomes possible to use a manual transmission, which allows increasing the torque. Since the electric motor has a wide range of rotation speed, two mechanical gears (working and transport) are sufficient. A sample of a mobile vehicle was used in the experimental studies.

НАБЛЮДАТЕЛЬ УПРУГОГО МОМЕНТА ДВУХМАССОВОЙ ЭЛЕКТРОМЕХАНИЧЕСКОЙ СИСТЕМЫ

To reduce the accident rate and increase the service life of electromechanical systems with shock load changes, the monitoring of elastic moments in mechanical gears is necessary. This task is relevant for the main lines of stands of hot rolling mills. The implementation of monitoring systems based on physical measuring devices is inefficient due to their complexity and low operational reliability. As an alternative, a relatively simple elastic moment observer is proposed, which is a fragment of an industrial controller software. The structure of the observer is presented and its advantages in comparison with known analogues are shown. The adequacy of the measured and reconstructed elastic moment signals is proved using the example of electromechanical systems of the stand of the thick-sheet mill 5000. A quasi-experimental analysis of emergency modes is substantiated, which allows the processing of signals stored in the form of data arrays. Based on this approach, an assessment of the dynamic moments in the emergency shutdown mode of the crate with metal in the rolls is given. The expediency of creating an online monitoring system for overloads of spindles and methods for calculating their resource is emphasized.

Rotation angle evaluation of a rotation mechanism including crown gear for controlling the posture around the axis of a flexible surgical tool

In this study, we proposed a rotation mechanism for controlling the posture around the axis of a flexible surgical tool for treatment deep inside the body. The mechanism includes crown gears and is driven by wire. In this method, the flexible forceps are fixed to the crown gear rotating mechanism placed at the tip of a sheath device, and the crown gear rotating mechanism is driven by the wire. The rotation mechanism can rotate infinitely. We designed and prototyped a crown gear push-up mechanism and a wire pulling mechanism, and evaluated the rotation angle of the crown gear rotation mechanism. The wire pulling mechanism was actuated by a motor and the rotation angle was measured a rotary potentiometer. As the result of the rotation angle evaluation experiment, 324° rotation was confirmed clockwise and 90° rotation was confirmed counterclockwise. In this paper, we confirmed that the rotation around the axis of a flexible surgical tool is possible within the range of ±90°.

Development of Robotic Hand for Prosthetic Limb using a Gear Mechanism for Infants with Congenital Upper Limb Defects

Development of Robotic Hand for Prosthetic Limb using a Gear Mechanism for Infants with Congenital Upper Limb Defects