Conventional Gear Research Articles

First Optical Seismometer at the Top of La Soufrière Volcano, Guadeloupe

Abstract Accurate monitoring of volcanic activity demands expertise in fields including geophysics, geology, and geochemistry. Data obtained from the most recent technical advances are particularly vital in pre-eruptive phases. In particular, seismic monitoring in near real time is essential to locating and discriminating early signs among different sources of seismic waves, especially those related to movement and overpressure in underground fluids. Among the major indicators of volcanic restlessness are fumaroles, or gas and steam vents, often located near a volcanic summit. Their activity could be monitored by seismometers in their vicinity, but today’s standard instruments cannot last very long when exposed to the high temperatures and the billowing, sulfurous, acidic gases near a fumarole. Conventional gear may also not be accessible for emergency deployment, or repair, even in pre-eruptive phases. La Soufrière de Guadeloupe Volcano in the Caribbean typifies such challenges. Its last significant event was a phreatic (gas and steam) eruption in 1976 that prompted evacuation of the archipelago’s nearby capital. Since early 2018, the 1467-meter-high stratovolcano has shown signs of increased activity. To provide a hardy, high-resolution monitoring system, we installed a recently developed type of seismometer just 10 m from a vigorous summit fumarole. The sensor is a purely opto-mechanical geophone that is interrogated through a 1.5 km fiber-optic cable by a remote, and thus it is a much safer optic-electronic system down the volcano’s flank. The ESEO Group and the Institut de Physique du Globe de Paris (IPGP) started development of this novel seismometer in 2008. The 2019 Guadeloupe installation is part of the HIgh PERformance SeISmometer (HIPERSIS) project (French Agence Nationale de la Recherche [ANR]). It is, to our knowledge, the first high-resolution optical seismometer ever installed on an active volcano or other active, hazardous zone. We report here the details of this installation, the means we are using for measurements, and our implementation strategy, and we share some of the first results. Such an optical seismometer, as well as a variety of other geophysical sensors built on the same principle, can be installed in a wide variety of sites with fibers up to 50 km long.

Use of the SmeltCam as an Efficient Fish Sampling Alternative Within the San Francisco Estuary

Resource managers often rely on long-term monitoring surveys to detect trends in biological data. However, no survey gear is 100% efficient, and many sources of bias can be responsible for detecting or not detecting biological trends. The SmeltCam is an imaging apparatus developed as a potential sampling alternative to long-term trawling gear surveys within the San Francisco Estuary, California, to reduce handling stress on sensitive species like the Delta Smelt (Hypomesus transpacificus). Although believed to be a reliable alternative to closed cod-end trawling surveys, no formal test of sampling efficiency has been implemented using the SmeltCam. We used a paired deployment of the SmeltCam and a conventional closed cod-end trawl within the Napa River and San Pablo Bay, a Bayesian binomial N-mixture model, and data simulations to determine the sampling efficiency of both deployed gear types to capture a Delta Smelt surrogate (Northern Anchovy, Engraulis mordax) and to test potential bias in our modeling framework. We found that retention efficiency—a component of detection efficiency that estimates the probability a fish is retained by the gear, conditional on gear contact—was slightly higher using the SmeltCam (mean = 0.58) than the conventional trawl (mean = 0.47, Probability SmeltCam retention efficiency > trawl retention efficiency = 94%). We also found turbidity did not affect the SmeltCam’s retention efficiency, although total fish density during an individual tow improved the trawl’s retention efficiency. Simulations also showed the binomial model was accurate when model assumptions were met. Collectively, our results suggest the SmeltCam to be a reliable alternative to sampling with conventional trawling gear, but future tests are needed to confirm whether the SmeltCam is as reliable when applied to taxa other than Northern Anchovy over a greater range of conditions.

A Novel Flux-Switching Magnetic Gear for High-Speed Motor Drive System

Magnetic gears realize the characteristics such as low acoustic noise and low vibration, maintenance-free by contact-less power transformation. However, conventional magnetic gears are not suitable for high-speed motor drive systems because of their low mechanical strength, which results from the permanent magnets of the input rotor. This article proposes a novel flux-switching magnetic gear for high-speed motor drive systems. The input rotor of the flux-switching magnetic gear consists of an iron core. Therefore, the structure is highly robust and can be driven in the high-speed region. Moreover, the flux-switching magnetic gears offer a high torque density by utilizing stationary field magnets arranged between the pole pieces. Through simulations and the experiments, parameters such as the torque density, mechanical strength, losses, and efficiency of the proposed gear are evaluated.

Electromagnetic Analysis of Linear Magnetic Gears Based on the Characteristics of Their Flux-Modulation Poles

Magnetic gears (MGs) are energy converters that have recently received attention because of their advantages over conventional mechanical gears. Prior studies focused on MGs without mechanical losses, and research on linear MGs has focused on tubular structures. Therefore, in this study, we analyzed the electromagnetic characteristics of the materials used in flux-modulation poles. In addition to comparing the electromagnetic characteristics of each material, an equivalent stress analysis was performed. Finally, the proposed model was fabricated, and experimental verification was performed.

Dynamics of integrated planetary geared bearings

The gear bearing drive is a new robotic transmission that was developed by NASA for compact and lightweight robotic applications. Compared to conventional simple and compounded planetary gear trains, the mechanical assembly of the gear bearing drive does not require a planetary carrier and individual planet needle bearings to maintain the gearset alignment. Instead, the design integrates the gearing and bearing functions together such that a constant pressure angle is maintained throughout the mesh cycle by the use of cylindrical rollers that are mounted parallel to the gear mesh. This paper examines the vibration characteristics of this planetary architecture and extracts its natural frequencies and mode shapes using both analytic and finite element methods. The design is compared against a conventional system with a floating carrier for comparative analysis. A simple and systematic approach to analytically and numerically solve the dynamics of complex, multi degree of freedom gear train systems using MATLAB is presented that can be easily applied to study other complex non-linear dynamic systems.

The influence of the angles of the asymmetrical gear rack on the geometrical and functional parameters for the pinion and gear with asymmetric teeth

The paper presents some research on the design of the asymmetric gears, special gears with involute asymmetrical teeth. The aim of these researches is to establish the influence of the angles of the asymmetrical gear rack upon some geometrical and functional parameters of the gears. We have used, as design method, the direct gear design, followed by the gear rack design, considering that asymmetric gears are not conventional gears, so the design method it is not the standard one. The results that are presented was obtained by using a computer modelling program, for asymmetric gears, in MatLab, and for one can see the asymmetric gears and the zone of the tooth action, a computer program in AutoLISP is developed. Based on the computer applications developed for determinate the geometrical parameters and for representing the teeth and gears models, the asymmetric teeth pinion and gear can be manufactured. Between the design parameters established at starting the described process there are the angles of the asymmetrical gear rack.

A hybrid three-wheeler e-gear using three-stage inverter

This work is intended to design the PMSM motor for a three-phase inverter and electronic gear equivalent circuit with two three-stage inverters for a three-wheel traction application. It also compares the performance parameters with the conventional gear. In recent times, Permanent Magnetic Brush Less DC (PMBLDC) and Permanent Magnetic Synchronous Motor (PMSM) motor drives have gained attention by establishing themselves as a potential alternative for conventional variable speed drives. The PMSM is widely used in many applications due to its high efficiency, torque ripple, high torque, and high performance, low and high-speed operation. This project includes inverter simulation using MATLAB simulation for speed and torque performance. By analysing the result, it can be seen that the proposed three-stage inverter-based e-gear for three-wheeler transmission offers better performance in continuous output power and torque compared to conventional gears.

Izbor optimalnog dvostepenog planetarnog prenosnika za pogon ribarskog broda

Planetary gear trains (PGTs) offer numerous benefits when compared to conventional gear trains, e. g. multi-carrier planetary gear trains may be built by linking the shafts of different component planetary gear trains. A two-carrier two-speed PGT consisting of two coupling shafts and four external shafts is a special type of multi-carrier PGT. This type of compound gear train has many important characteristics, the most notable being the possibility to change the transmission ratio under load. This paper presents a method for quick determination of the structure and important basic parameters of two-speed planetary gear trains that meet the predefined transmission requirements. A computer program developed for the examination of two-speed planetary gear trains DVOBRZ is used for this purpose. A numerical example of the procedure is provided, dealing with the application of a two-speed PGT as a fishing boat reduction and reversing gearbox.

Development of CFD-based procedure for 3d gear pump analysis

Tumbling Multi-Chamber (TMC) gear pump is a generally unknown type of hydraulic device, which features a unique three-dimensional shape of the gears. The main benefits of such design over the conventional gear pumps are self-adapting tightness of the pump parts, the possibility to mold the parts from a polymer material and high volumetric efficiency, considering the simplicity of the design. The specific working principle of TMC pumps requires a slightly different approach to the numeric modeling and analysis process compared to the conventional gear pump types (e.g. external gear and gerotor pumps). One of the main contributions of the work is the development of an analysis procedure, which allows studying flow and pressure conditions in the TMC pump. This includes the influence of the positioning of the pump parts on spatial and temporal variations in sealing regions and the influence of pressure field propagation in relation to the valve plate position.

Methods of the driver’s activity when fulfilling the tasks in emergency

The article deals with the algorithm of the vehicle driver control activity using the method of logic-probabilistic modeling. When performing military automobile transporting in conditions of intense traffic flow, in conditions of performance of military-combat tasks the driver undergoes a significant amount of visual and auditory influences, the frequency of which increases significantly in situations that can cause incidents of traffic accidents. The driver is the operator of the system «driver-car-road-environment», the service processes are mainly reduced to the reception and analysis of operational information, decision-making that controls the actions and control of their implementation. Lack of time and necessary information, intense and uneven information load while driving the vehicle leads to the development of the driver psychological stress. At the same time, the important psycho-physiological characteristics of the driver deteriorate substantially, such as a complicated motor reaction, characterized by the average duration of response time, emotional stability and stability of attention. The factors that determine the possibility of traffic accidents, among others, include driver's level of qualification, his physical and psycho-physiological characteristics. In this case, the term of the reaction of the driver, which is an integral indicator of the visual-motor system, is of great importance. A long reaction time increases the risk of road traffic accidents which can cause both material and human losses. The car is the object of management in the «driver-car-road-environment» system. In recent years there is a continuous increase in the number of cars and improving their speed characteristics. In this regard, the safe operation of a modern car requires the use of modern pedagogical tools and training methods for drivers. In these conditions, not the knowledge of its design is essential for the effective operation of the car, but the knowledge of its properties as an object of management, understanding the role of automatic systems, the ability to perform operations with the control of these systems, the ideas about changing the properties of the car in the case of the failure of such systems. The safety of the vehicle driving depends on the psychological characteristics of drivers, the ability to perceive unexpected information quickly and respond to itadequately. Vision, hearing and touch are the most important channels of perception of information. The level of safe driving depends on the characteristics of mental processes, such as: attention, memory, thinking, psychomotor, sensation and perception, since they play an important role in the vehicle driving. Estimation of the driver's activity in terms of the degree of complexity of the driving of motor vehicles of standard sizes and the nature of the route must be complex, taking into account the design features of the control of vehicles and conditions of movement on the route. It must be carried out in different ways and take into account its various components. During the work the driver performs a large number of actions which seem to be quite simple such as pedaling, pressing the levers, turning on and off the toggle switches, turning the steering wheel. All these driving actions are carried out in a certain order, depending on typical traffic situations. During the operation, the driver performs a large number of motor activities, and the amount of effort applied to the control of the car, is quite large and different. Therefore, it is advisable not just to take into account the typical actions of the driver, but to estimate them by the amount of the efforts applied to the control of the car. A significant disadvantage of this method is the disregard for technical factors that affect the complexity of the driver activity of vehicle management (overall length, gross vehicle weight, type of gearbox design). It should also be noted that the nature of the connection between the complexity of the official driver activity and fuel consumption can be different. For example, considering the movement of a vehicle with a variable longitudinal profile of the traffic route, it can be noted that fuel consumption is greater when moving on the rise, and the difficulty, on the contrary, when driving on the descent. Comparison of fuel consumption and complexity of vehicle control processes, equipped with a hydro mechanical gearbox and conventional mechanical gear shows that fuel economy is less, and the complexity of the driving is lower. The use of methods of algorithmic analysis in road transport is a scientifically grounded method, an analysis of working processes with the introduction of their quantitative characteristics, having a certain psycho physiological content. The principle of this method is to decompose the work process into qualitatively different elemental components. The work of the car driver is presented as a logical activity, consisting of a set of actions and operational units of information. Examples of application of the algorithm and evaluation of the driver's activity on the control of the vehicle are considered.

Relative benthic disturbances of conventional and novel otter boards and ground gears

A benthic trawl’s substrate contact (e.g. spreading mechanisms (i.e. otter boards) and ground gears) determines both its catching efficiency and the extent of perceived habitat impacts. The potential for mitigating habitat impacts was investigated here via the novel ‘batwing’ otter board and ‘soft-brush’ ground gear. A purpose-built testing assembly towed treatments across three artificial habitat types with incrementally greater detachment thresholds (~ 8, 32 and 56 N), and the batwing and soft-brush were alternately compared against a conventional flat-rectangular otter board and three chain ground gears (6-, 8- and 10-mm diameter link), respectively. Overall, during 48 alternate deployments, the batwing removed up to 61% fewer of all habitats than the flat-rectangular otter board. By comparison, during 42 alternate replicates, the soft-brush ground gear failed to displace any habitat, while all three chain ground gears similarly removed between 3 and 5% of the two least resistant habitats (irrespective of position). The results imply the perceived impacts of penaeid trawls across sensitive areas can be reduced via simple modifications to spreading mechanisms and ground gears, along with appropriate spatio-temporal regulation. This study represents a unique approach to understanding the relative differences in impacts between ground gears and commercial-sized otter boards under controlled conditions.

A Review on Magnetic Gears: Topologies, Computational Models, and Design Aspects

Geared devices are commonly used to match the operating speed and torque of the power source with the second mover. Such geared devices are usually mechanical gears. As counterparts of the conventional mechanical gears, magnetic gears (MGs) are becoming promising devices, mainly due to the merits of physical isolation between moving parts, no gear lubrication, no mechanical fatigue, inherent overload protection and reduced maintenance, etc. Recently, several new topologies have been proposed to achieve better performances. In this paper, a general review of MGs is presented, including a discussion of the most common and upcoming topologies and a description of the working principle. A comparison of different topologies is carried out in terms of gear ratio and torque density. The main computational techniques generally adopted for coaxial MGs are listed and described. Some key aspects concerning the design, the existed challenges, and potential applications are also discussed. This paper aims to provide a comprehensive overview of the MG for readers working in this field.

Research on innovative design of a new rope knotter

Aiming at the complex structure and high manufacturing process requirements of traditional knotter, this article proposes a new rope knotting method. Based on the knotting method, a knotter is designed to use a new mechanism which is made up of two new incomplete gear mechanisms to drive rope clamping mechanism and rope hooking and griping mechanism. First, a kinematic cycle diagram of the knotter is determined, and the structures of each key mechanism are designed. Then, a virtual prototype of the knotter is established by Unigraphics and imported into Automated Dynamic Analysis of Mechanical Systems to analyze the kinematic of each key mechanism. The success rate is 98.4% through 500 physical tests on the physical model of the knotter. The results indicate that the knotting method is reliable. The knotter can meet the requirements of structure, posture, and coordination during knotting process. The new knotter has no separate mechanism for cutting rope and tripping out of the rope buckle. Therefore, the structure is simplified and reduces the design and manufacturing difficulties. Furthermore, the new incomplete gear mechanism solves the problem that in the conventional incomplete gear mechanism, the driven gear can swing at a large angle or even cannot be locked in the case when the locking arc of the passive gear is too short.

Influence of tribological conditions on application relevant component properties of cold forged gears

In recent years there have been increasing attempts to enable the production of net-shape gears by forming methods. Cold forging enables improved material and energy efficiency compared to conventional gear manufacturing processes. In the extrusion process, a high surface quality, an increased hardness of the tooth profile as well as a load adapted fibre orientation is achieved. The procedure thus offers the potential to manufacture net-shape gears in a process suitable for series production. Due to the high tribological loads resulting from pronounced deformation and surface enlargement, the tribological conditions substantially influence the process result and the application relevant component properties. The tribological conditions are mainly affected by the applied lubrication system. The aim of this contribution is to investigate the influence of tribological conditions on the resulting component properties of cold forged steel gears. For this purpose different lubrication systems with and without a phosphate conversion layer are applied and the resulting component properties are determined. Phosphate-free lubrication systems offer substantial potential, especially from an ecological point of view. However, the high tribological loads during gear manufacturing pose a challenge. Based on the determined change of the tribological conditions and the resulting component properties, functional correlations are identified. The results show that friction has a distinct influence on the die filling and the application-relevant component properties.

Design of a cost‐effective magnetic gearbox for an aerospace application

Magnetic gears are designed to perform in a highly reliable manner, and offer several advantages compared to mechanical gears but difficulties with manufacturing techniques and cost are strong handicaps. In contrast to conventional gears, the contact and lubrication free force transmitting elements lead to a considerable lifetime and range extension of drive systems. In recent years, magnetic gears have been extensively researched and discussed by both academics and engineers from different industries. However, the vast majority of published work on magnetic gearing relates to novel topologies and performance improvement but not on optimisation of cost and weight. With a judicious parametric model analysis, design can be optimised in terms of torque capability, cost and weight. Moreover, the design process is time and cost consuming, but can be also be reduced by the use of modelling methods. An earlier paper addressed the parametric model approach and its benefits, but did not include a comparison between test and simulation data. This study will summarise the findings and present the test data from a magnetic gearbox designed for an aerospace application such as a high lift system.

A Novel Reluctance Magnetic Gear for High-Speed Motor

Magnetic gears are expected to be a maintenance-free system with low-noise and low-vibration characteristics by a noncontact power transmission. However, conventional magnetic gears are not suitable for use with high-speed motors because the mechanical strength is weak due to the use of permanent magnets in a high-speed rotor. Additionally, the magnet eddy current losses in the high-speed rotor seriously decrease the gear's efficiency during a high-speed operation. This paper presents a novel reluctance magnetic gear that can realize the high-speed drive and high efficiency. The high-speed rotor of the proposed magnetic gear is constructed by only an iron core. Therefore, the structure is very simple and robust, adding that it is possible to rotate in the high-speed region. Moreover, the proposed magnetic gear achieves high efficiency in the high-speed region because the magnet eddy current loss in the high-speed rotor is not generated because no magnets are used. The downsizing of the system and a high efficiency power transfer are realized by applying the proposed reluctance magnetic gear.

Reduction of the tonality of gear noise by application of topography scattering

In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to the gear excitation. Within the past years, a lot of investigations have shown that the noise emission can be correlated to the quasi-static transmission error. Therefore, the transmission error can be used as a characteristic value for quality assurance by conducting experimental inspections as well as a tooth contact analysis in the design process.An optimization approach to solve gear whine issues is the reduction of the gear mesh excitation. In this report, a novel optimization approach for gears is presented. A targeted topography scatter from tooth to tooth is applied on the teeth of the gear set, in order to manipulate the composition of the gear mesh excitation. As a result of the slight deviations for each tooth mesh, the regularity of the transmission error excitation is broken up leading to a reduction of the tonality of the resulting gear whine.In the first step, different topography scatter variants are calculated in the tooth contact analysis. Based on the transmission error spectra, two variants with a topography scatter are chosen for manufacturing. The evaluation of the predicted excitation behavior is evaluated on a conventional bevel gear tester by means of single flank tests. A test fixture for the evaluation of the operational behavior under loaded and dynamic conditions is used to compare the measured and simulated dynamic excitation behavior. In order to simulate the dynamic behavior, a torsional multi-body-simulation model of the powertrain is developed that uses the stiffness of the gear mesh calculated by the tooth contact analysis as input data for the excitation forces. The force-coupling-element connects the drive and the driven train and forms the excitation of the gearing.Finally, it is the aim to evaluate the impact of the targeted topography scatter psychoacoustic parameters, such as loudness, sharpness, roughness and tonality. The potentials of the topography deviation for the optimization of ground bevel gears in terms of tonality reduction will be shown by means dynamic test rig trials.

Investigation on the Backlash of Roller Enveloping Hourglass Worm Gear: Theoretical Analysis and Experiment

This paper proposes a single-roller enveloping hourglass worm gear design and verifies its advantages compared to the existing double-roller worm gear system and the conventional worm gear set. Our hypothesis is that the single-roller worm gear with appropriate configurations and parametric values can eliminate the backlash in mating gear transmission while maintaining advantages of the double-roller worm gears. Also, the self-rotation of the rollers when they are in the worm tooth space (TS) will help the gear system to avoid jamming and gear tooth scuffing/seizing problems caused by zero backlash and thermal expansion. In order to test that hypothesis, a mathematical model for the single-roller enveloping hourglass worm gear is developed, which includes a gear engagement equation and a tooth profile equation. Using that model, a parametric study is conducted to inspect the influences of center distance, roller radius, transmission ratio, and the radius of base circle on the worm gear meshing characteristics. It is found that the most effective way in eliminating the backlash is to adjust the roller radius and the radius of base circle. Finally, a single-roller enveloping hourglass worm gear set is manufactured and scanned to generate a 3D computer model. That model is compared with a theoretical model calculated from the developed mathematical model. Comparison results show that both models match very well, which verifies the accuracy of the developed mathematical model and our initial hypothesis that it is possible to achieve transmissions with zero backlash by adjusting the design parameters.

Three-Dimensional Printing of Abrasive, Hard, and Thermally Conductive Synthetic Microdiamond–Polymer Composite Using Low-Cost Fused Deposition Modeling Printer

A relative lack of printable materials with tailored functional properties limits the applicability of three-dimensional (3D) printing. In this work, a diamond-acrylonitrile butadiene styrene (ABS) composite filament for use in 3D printing was created through incorporation of high-pressure and high-temperature (HPHT) synthetic microdiamonds as a filler. Homogenously distributed diamond composite filaments, containing either 37.5 or 60 wt % microdiamonds, were formed through preblending the diamond powder with ABS, followed by subsequent multiple fiber extrusions. The thermal conductivity of the ABS base material increased from 0.17 to 0.94 W/(m·K), more than five-fold following incorporation of the microdiamonds. The elastic modulus for the 60 wt % microdiamond containing composite material increased by 41.9% with respect to pure ABS, from 1050 to 1490 MPa. The hydrophilicity also increased by 32%. A low-cost fused deposition modeling printer was customized to handle the highly abrasive composite filament by replacing the conventional (stainless-steel) filament feeding gear with a harder titanium gear. To demonstrate improved thermal performance of 3D printed devices using the new composite filament, a number of composite heat sinks were printed and characterized. Heat dissipation measurements demonstrated that 3D printed heat sinks containing 60 wt % diamond increased the thermal dissipation by 42%.

Improving strength for automotive plastic gears through directional fibre reinforcement

In this paper, a new topology of reinforcing plastic gears with carbon fibres is introduced. The reinforcement is placed tangentially to the critical cross section at the tooth fillet to improve bending strength. The mechanical modelling of the fibrous reinforcement is performed using an anisotropic material stiffness matrix derived from the analysis of a representative volume element using commercial stress analysis software. Benchmarking against conventional plastic gears illustrates that the maximum fillet stress, which is responsible for tooth failure in overloading conditions is greatly reduced, therefore rendering these gears suitable for considering their use in high load applications such as in the automotive industry. Also, the effect of the thickness of the reinforcement on the maximum developed tensile stress at the root is examined. The results show significant decrease of the bending stress at the root fillet rendering this design an alternative way in reinforcing plastic gears.