Nylon with various reinforcements is utilized for composite gear preparation; however, the composite specimens have less strength and a higher wear rate. Moreover, the materials and processing costs ...are high when selecting various mix proportions. Hence, this research has examined the impacts of adding Graphene oxide (GO) and Tungsten disulphide (TD) with Nylon 66 (PA66) on the tribological and mechanical properties. The research aims to identify the best hybrid nylon-reinforced composite specimen for composite gear manufacturing. The GO was prepared by the Modified Hummers-based method and coated with epoxy resin by dip coating. Further, a novel Decision Buffalo-based Mix Selection (DBbMS) has been developed for selecting the best mix proportions to reduce the processing time and material cost. The test specimens are set up by varying the rates of coated GO and TD blended with PA66. In addition, the test examples for tribological and mechanical tests were shaped using an injection moulding machine. The mechanical and tribological properties of PA66, TD, and GO mixed with PA66 hybrid composites were identified. The PA66 composite with 4wt% TD and 15wt% coated GO (PTO-3) uncovered better strengths and higher wear and erosion resistance. In this work, PTO-3 hybrid composite material has been utilized for gear manufacturing.
Although gearboxes with composite gear trains have been widely used in industrial production, it remains difficult to extract their fault signal features due to relatively complex vibration signals. ...This paper proposes an effective fault feature extraction method based on ensemble empirical mode decomposition (EEMD) and translation-invariant multiwavelet neighbouring coefficients, through which a clear envelope spectrum of gearbox vibration signals can be obtained. Compared with EEMD denoising or translation-invariant multiwavelet denoising using neighbouring coefficients alone, the method combining both of the denoising approaches can not only effectively suppress the signal noise but also fully retain the fault feature information. The presented method was further experimentally verified using a test rig for a gearbox with a composite gear train. Fault diagnosis was conducted with a single fault, such as snaggletooth and abrasion, as well as mixed faults at different locations. The results have shown that this method can effectively extract the fault features and improve the fault detection rate of a gearbox with a composite gear train. Keywords: composite gear train; feature extraction; EEMD; multiwavelet neighbouring coefficients
The present study aims at developing light weight polymer composite spur gear and improving the performance. Various types of reinforcements and fillers have been used in the polymer gears in order ...to enhance the performance. There is some evidence in the literature that the metal foamsexhibit significant mechanical properties. The idea here is to use metal foam as a reinforcement material in polymer spur gear and to investigate the performance. The main objective of the present study is to investigate the influence of metal foam properties on the performance of polymer composite spur gear. Two part epoxy adhesive was used to fabricate spur gears. Two different metal foamslike aluminium and nickel with different porosity levels were used in order to have different properties of foams. The epoxy adhesive mixture was cast on the metal foam sheet, and gears were cut by abrasive water jet cutting process after curing of adhesive. The reinforced and unreinforced polymer gears were tested by an indigenously developed gear test rig with standard gear made of mild steel. The testing was carried out at different torque levels and at a constant speed, and the number of cycles was monitored. In the results, the metal foam reinforced gears show better performance than unreinforced polymer gear. In the case of polymer composite gear, nickel foam which has larger tensile strength, flexural strength and smaller porosity level shows better performance comparatively.It is concluded that choosing metal foam with better strength and smaller porosity help us improve the performance of the polymer composite gears.
A new design method for polymer composite gear has been proposed in the current paper. This design method is based on the link between polymer gear wear rate and its surface temperature. It has been ...found from the tests that the polymer (acetal) gear wear rate will be increased dramatically when the load reaches a critical value for a specific geometry. The gear surface will wear slowly with a low specific wear rate if the gear is loaded below the critical one. The possible reason of the sudden increase in wear rate is due to the gear operating temperature reaching the material melting point under the critical load condition. Gear surface temperature has been then investigated in detail through three components: ambient, bulk and flash temperatures. Through extensive experimental investigations and modelling on gear surface temperature variations, a general relation has been built up between gear surface temperature and gear load capacity. The method has been related to test results under different operating ambient temperature and gear geometries. Good agreement has been achieved between the proposed method predictions and experimental test results. Experimental investigation on polymer composite (glass fibre reinforced nylon with PTFE as internal lubricant) gears have also been carried out and two forms of failure have been found, root and pitch fractures.
Hybrid gears made of steel and fiber-reinforced polymeric composite material are recently attracting electric vehicle designers’ attention due to their possible advantages such as lightweight and ...lessened transfer of noise and vibration for automotive transmissions. Polymeric composite material may be placed in-between the steel teeth and central hub regions in the radial direction of the gear. The partial usage of polymeric composite material for a gear is expected to reduce the transmissibility of vibration from teeth to hub as well as the weight of the gear-train. Using the finite element method, optimization, vibration and noise analyses have been performed in order to calculate SPL (sound pressure level) for pure steel and hybrid gears, separately. At a specified point of a tooth and a hub, the changes in SPL are computed and are compared to check how effective the polymeric composite region is. The reduction in SPL of the hybrid gear is observed by comparing to that of a pure steel gear. To minimize the weight of the hybrid gear, design optimization is applied by considering fatigue strength of steel and composite material.
This paper describes a detailed analysis of the flash temperature for polymer composite gears and the heat partition between gear teeth. The problem is treated as an unsteady one where the intensity ...distribution and velocity of heat source changes as meshing proceeds. A numerical approximation is adopted using finite different method and the results are shown to be close to those found using semi-analytical method assuming no internal hysteresis and the material properties are constant. It is shown that Blok's solution can be used to provide a quasi-steady approximation that is for mean flash temperature estimation. However, if the gear teeth start and end meshing positions are considered, Blok's solution is inaccurate and the current approach should be used.
Abstract
A new type of polymeric composite material spur gear was developed and fabricated using low cost Portland pozzolana cement (PPC) particles as filler into the polypropylene (PP) matrix. PP ...granules were mixed with PPC particles and an injection-molding process was followed to manufacture the thermoplastic composite gear. Several experiments were conducted with different percentages of PPC particles with the PP to optimize the gear material (cement filled poly-propylene composite) for fabrication. Tensile tests were conducted and the morphological studies of the fractured surface of the gear materials were investigated using scanning electron microscopy (SEM) and field emission SEM (FE-SEM). Dynamic mechanical analysis (DMA) was carried out and viscoelastic properties of the gear materials were studied with varying temperature. Further, extensive experimental studies were carried out to evaluate the performance of the gear tooth under loading conditions. The experimental results validate the suitability of the proposed non-metallic spur gear for low cost industrial applications.
According to the characteristics of the self-healing composite gear, the mould for gear is designed elaborately in this paper including the selection of mould type and material, the structure design ...of injection mould and gating system, the verification of injection parameters and the design of the demoulding mechanism. It provides good foundation for further manufacture and property analysis of the self-healing composite gear.
By designing the different formulations of the composites and adopting optimized technology including extrusion and molding, the effects of the Micro-capsules on the properties of nylon composites ...are analyzed by the impact property test. The mechanical impact property of the glass fiber reinforced nylon composites is influenced little if the content of the self-healing microcapsules added is less than 3.5%, and the technology of self-healing microcapsules used in the polymer composite gear is feasible.
Recently, low noise gears without lubrication are required for business machines and robots, because they are used in open space. The present article provides a new type gear consisting of steel and ...resin (called Delrin-100), which has good lubrication characteristics. Our gear has profile shifted steel gear teeth. Delrin-100 resin is inserted in a grove, which is cut around the gear teeth of the steel gear so as to have strong gear teeth. Hence, the tooth made of Delrin resin is supported at both sides. This means that only resin gear tooth contacts to the follower gear tooth, but steel gear tooth does not contact. Production processes are presented for the gear, and its characteristics are investigated. It is ascertained that the strength of our gear is greater than that of a plastic gear, and noise of our gear is small in comparison with plastic gears. The design method is presented, and effects of frictions on the position control are also investigated.
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