Performance Evaluation of a Small-Scale Mechanical Fish Feeder

The performance evaluation of an existing mechanical fish feeder was carried out. Floating feeds of sizes 2 mm, 4 mm, and 6 mm at constant moisture content of 13 % were fed into the feeder. The feeder was powered by a 3-phase, 1.5 kW reducing gear electric motor at speed 40 rpm, 50 rpm, 60 rpm, 70 rpm and 80 rpm machine. It was observed that the horizontal screw conveyor effectively transported the material from the hopper to the discharged point. The results obtained from the tests showed an optimal performance of the machine at speed 50 rpm with dispensing efficiency of 93.1 % for 2 mm feed size, while the throughput was 75.76 kg/h at motor speed of 80 rpm also for the 2 mm fish feed size. The ANOVA at p ≤ 0.05 showed that machine speed has significant effect on its dispensing efficiency and the throughput capacity. The cost of production of the mechanical fish feeder was ₦262,300 which made it affordable for young entrepreneurs.

On one criterion for estimating technical condition of a mining machine reducing gear

The developed Procedures for estimating technical condition of mining machines reducing units based on reference spectral masks got approval at the producer’s plant during run-in test at the testing facility and in industries. The approval results of the introduced criterion bear compelling evidence about the rectitude of the chosen approach for diagnosing sophisticated technical systems.

The Influence of Pulling Up on Micropitting Location for Gears with Interference Fit Connections of Their Conical Surface

Micropitting is a surface fatigue phenomenon that occurs in Hertzian type of rolling and sliding contact that operates in elastohydrodynamic or boundary lubrication regimes and can progress both in terms of depth and extent. If micropitting continues to propagate, it may result in reducing gear tooth accuracy, increasing dynamic loads and noise. Eventually, it can develop into macropitting and other modes of gear failure such as flank initiated bending fatigue. Micropitting has become a particular problem in the gear surface fatigue. Usually micropitting initiates in the dedendum of the driver and driven at the asperities on the surface. However, the authors found for some gears with interference fit connections of their conical surface, micropitting on the pinion occurs in the addendum. This study attempted to find the reason using a 3D–TCA method based on ISO/TR 15144-1 to predict the micropitting and try to understand the key influence likely to affect micropitting location.

Noise Reduction in Spur Gear Systems

This article lists some tips for reducing gear case noise. With this aim, a static analysis was carried out in order to describe how stresses resulting from meshing gears affect the acoustic emissions. Different parameters were taken into account, such as the friction, material, and lubrication, in order to validate ideas from the literature and to make several comparisons. Furthermore, a coupled Eulerian–Lagrangian (CEL) analysis was performed, which was an innovative way of evaluating the sound pressure level of the aforementioned gears. Different parameters were considered again, such as the friction, lubrication, material, and rotational speed, in order to make different research comparisons. The analytical results agreed with those in the literature, both for the static analysis and CEL analysis—for example, it was shown that changing the material from steel to ductile iron improved the gear noise, while increasing the rotational speed or the friction increased the acoustic emissions. Regarding the CEL analysis, air was considered a perfect gas, but its viscosity or another state equation could have also been taken into account. Therefore, the above allowed us to state that research into these scientific fields will bring about reliable results.

STARTING UP AND REGULATING THE ROTATIONAL SPEED OF A POWERFUL ELECTRIC DRIVE USING A MAGNETIC REDUCING GEAR

The article examines a magnetic reducing gear, the stator winding of which receives power in the mode of a valve machine. In the absence of this supply, the electric motor can be started-up in no-load mode. To significantly reduce the power of the magnetic reducing gear frequency converter compared to the power of the adjustable electric motor, it is necessary to make the number of the rotor's pairs of poles with permanent magnets of a magnetic reducing gear large enough. In this case, the design of arranging the magnets in radial grooves is the most adequate, ensuring the concentration of fluxes per pole in the air gaps. The stator winding of such a magnetic reducing gear will be low-pole. When manufacturing a magnetic reducing gear, it is possible to use a stator magnetic core of a serial asynchronous machine together with its regular winding. The electromagnetic moments of the magnetic gearbox rotors are a consequence of the presence of a stator electromagnetic moment. The stator's current frequency is represented by two components, of which the first is defined from the state equations and the second is a constant forming an additional channel of functional influence. The speed of rotation of the gear shafts can be adjusted by changing the specified constant and the input voltage of the frequency converter. The equations of the magnetic reducer state describing its functional modes were solved by means of the Mathcad mathematical program.

Modeling drive wheels of hoisting machines with rubber cables

Upgrading of hoisting machines aims to improve their performance, to reduce risk of accidents, and to cut down operational and capital costs. One of the redesign solutions is replacement of steel cables by rubber cables. This novation can extend life of pulling members, decrease diameters of drive and guide wheels and, consequently, elements of the whole hoisting machines: rotor, reducing gear, motor. This engineering novation needs re-designing of hoisting machines; thus, the new design should be validated, in particular, strength characteristics of the machine members. This article considers a drive wheel of a hoisting machine with a pulling belt. In order to justify the potential range of design parameters with regard to safety factor, the numerical models of different-design drive wheels are developed and their operation with pulling belt (rubber cable) is simulated in the SolidWorks environment. The data on the stress state of the wheel elements are analyzed, the most loaded points are identified, and the maximal stresses on the sidewall surface and in the spokes of wheels of different designs are plotted.

Integrated Analysis of Influence of Multiple Factors on Transmission Efficiency of Loader Drive Axle

In this study, a loader drive axle digital model was built using 3D commercial software. On the basis of this model, the transmission efficiency of the main reducing gear, the differential planetary mechanism, and the wheel planetary reducing gear of the loader drive axle were studied. The functional relationship of the transmission efficiency of the loader drive axle was obtained, including multiple factors: the mesh friction coefficient, the mesh power loss coefficient, the normal pressure angle, the helix angle, the offset amount, the speed ratio, the gear ratio, and the characteristic parameters. This revealed the influence law of the loader drive axle by the mesh friction coefficient, mesh power loss coefficient, and speed ratio. The research results showed that the transmission efficiency of the loader drive axle increased with the speed ratio, decreased when the mesh friction coefficient and the mesh power loss coefficient increased, and that there was a greater influence difference on the transmission efficiency of the loader drive axle.