Papers by Keyword: Gears

Abstract: The Guided Material Flow (GMF) process is an advanced variant of the Samanta process designed for the net shape cold extrusion of gears. The GMF process employs a modified die geometry to control material flow and significantly reduce maximum tool loads, effectively overcoming traditional process limitations. Key advantages include enhanced tooth tip strength and a reduction in face end deformations, which are characteristic defects in the conventional Samanta process. Minimising these deformations reduces the requirement for subsequent machining and enhances overall material efficiency. A numerical dataset was generated to train and validate data driven surrogate models, facilitating rapid process analysis without the computational cost of continuous Finite Element Analysis (FEA). The models developed in this paper enable the precise prediction of critical process outputs, including maximum punch force, die filling behaviour, material utilisation and strain hardening at the tooth tip. This paper details the numerical data acquisition, the specific training and validation methodologies of the machine learning models and demonstrates their capability to accurately predict complex process outcomes when varying the geometry of the die active surface in the GMF process.

Abstract: A low-cost method based on macro-photogrammetric reconstruction is presented to automatically detect wear and other defects in small gears created with additive manufacturing. This novel approach is oriented to preventive and predictive maintenance of gears in order to avoid faults in machines and devices. The experimentation has been conducted using three defective gears produced in Nylon PA-12. First, a robotic platform and a systematic macro-photogrammetric data acquisition procedure were used to accomplish the 3D reconstruction and generate the dense point clouds. Subsequently, a comparison between the dense point cloud and the ideal solid CAD model of the normalized gear has been carried out. For this aim, the models have been alignment in the same spatial system. The computation of the distances between solid models and point clouds allows the automatic visualization of different types of defects even for defects that are not visible to the naked eye. This conclusion has been checked from a statistical point of view considering the discrepancies obtained in the comparison and their distribution.

Abstract: The new technology of ensuring efficiency of reducers of construction machines is offered. The technology is based on the application of hardening coatings on the contact surface of the gear teeth. To implement the method, the authors developed an installation for applying hardening coatings by ion implantation. Similar devices used for the application of hard materials in the form of diffusion coatings on hot parts of tooling and machine parts are described. It is shown that the proposed installation has a greater technical and economic efficiency compared to existing analogues. The description of the design and operating principle of the proposed device is presented. The results of experimental researches of efficiency of the offered technology are presented. The modes of processing allowing to achieve the maximum indexes of working capacity are picked up. The conducted researches have shown the efficiency of the offered technology for the details from hard alloys.

Abstract: 17NiCrMo7, 19MnCr5 and 27MnCr5 low-alloy case-hardening steels samples have been investigated by SANS (Small-Angle Neutron Scattering), to achieve data on bulk nanoscale structure characterisation and complementary analytical and crystallographic information. The reported results are related in particular to the size distribution of nanosized pores which can help to comprehend the structural basis for the physico-chemical properties and thus to improve quality and durability of the considered materials. A complementary PIXE investigation has been also carried out, with the aim of a non-destructive assessment of the elemental composition of the considered samples.

Abstract: Gear is one of the machine components that is widely used in industrial and automotive fields. In machinery process, gear has a very important function to forward speed, power, or torque from one engine component to other components as a mechanical drive. Today a lot of development to obtain a good quality of gear, due to many gears were damage, worn out, and broken because they were not strong enough to resist friction and pressure. In addition, broken gears due to pressure and friction make them did not last long. To increase the hardness value of gear, then it needs though material that can be used when the gear reach optimum rotation. The material that is widely used for gear application is medium carbon steel. The medium carbon steel is a metal material that has carbon composition ranging from 0.30 to 0.59%. This medium carbon steel has hardness value of 174.501 HVN without treatment. The process of quench tempering and carburizing are conducted to increase hardness and toughness value of the material. The hardness value of gear is 140 HVN. The result of the research showed the hardness value at various temperature 780°C, 810°C, and 840°C. The optimum hardness values ​is 165.355 HVN at the temperature of 840°C. Medium carbon steel is expected to be an alternative to produce steel material with certain mechanical properties. This research also conducted heat treatment in austenite area and then detained with holding time of 20, 40, and 60 minutes. Furthermore, quench tempering was conducted and followed by carburizing to obtain a ferrite phase and coarse pearlite and to increase hardness value after quech tempering. It is expected that after quech tempering and carburizing process, steel with better mechanical properties can be produced. This research obtained the increase of hardness value and the number of pearlite and ferrite.

Abstract: This article describes load capacity of dynamically loaded gears, more precisely describes the mechanical pulsation tests of carburized gears with different thickness of case-hardened depth and case-hardening technology, i.e. addition or removal of certain steps during the case-hardening process of the tooth flank and foot root. The comparison was made on six different process chemical-heat treatment, in two thicknesses of case-hardened depth and two pressure angles. Results are shown and compared in a Wöhler’s curve.

Abstract: A gear plays a crucial role in the performance of a gear box. The faults in a gear reduces the gear life and if problem arises in shaft it affects bearing. Gear box is finally affected due to these faults. Vibration signals carries information about condition of a gear box which are captured using piezoelectric accelerometer. In this paper, features are extracted and classified using K nearest neighbours (KNN) algorithms for both time and frequency domain. The effectiveness of KNN in classification of gear faults for both time and frequency domain is discussed and compared.

Abstract: This paper approach the study of the dynamic behaviour of a real gear with asymmetric teeth which will replace the current gear with symmetrical teeth. Research approach is founded on two questions: How does the error of the flank's tooth form influence the dynamic behaviour of a gear How is the dynamic behaviour influenced by the configuration of a gear with asymmetric teeth compared with a gear with symmetric teeth, with comparable accuracy

Abstract: In this work, an experimental study of wear evaluation in combination with a finite element analysis (FEA) was carried out for austempered ductile iron (ADI) used in gears. Two different ADI materials were used to produce gears which were tested in a FZG back-to-back test rig. The experimental results were compared to those of carburized AISI 8620 steel and induction hardened AISI 4140 steel gears. The wear resistance for pitting and spalling on the gears surfaces were measured using image analysis. Comparing the two types of ADI, the one with smaller nodules showed a higher pitting resistance. In contact fatigue tests with severe load, the carburized AISI 8620 steel proved to be superior to ADI. However, ADI with smaller nodule size presented wear resistance similar to that of induction hardened AISI 4140 steel. The FEA was conducted using the commercial code ANSYS 11.0 and aimed to provide a better understanding of the microstructural effect on the stress state of subsurface regions. From the numerical results in ADIs, it was concluded that the nodule size affects the gears life independently of the mechanical properties of the matrix. The size and number of nodules affects both the nucleation and the propagation stages of cracks. ADIs with higher amount of nodules have a superior wear resistance by pitting. Also, compared to the Hertz contact theory (valid for isotropic materials), the presence of graphite nodules induced the maximum shear stress point moves toward the surface.

Abstract: Gears, due to their complex shape, carried load and required accuracy are ones of most complex aircraft engine parts. Single tooth damage usually breaks the power transmission and causes failure of the entire gear system. Adequate sustainability and guarantees of transmission is therefore a condition for secure operation of whole device. Particularly high requirements for reliability are put to transmissions used in the aerospace industry. Due to the loads which are transmitted through the gears, the materials used by the manufacturer must have not only high strength but also show the abrasion resistance of the surface layer and the ductility of the core. Thermo-chemical treatment of industrial gears is a fundamental process, which gives them adequate mechanical properties regarding loads they carry and the surface conditions of work. The most promising method in the discussed field is vacuum carburizing, which by its specification of work significantly reduce the emission of CO₂ and the duration of the process, without reducing the quality of the final product. The main aim of the paper is to present criteria for selection of carburizing parameters (mainly temperature increase) as a part of thermo-chemical treatment process performed using vacuum methods. Proper (higher to compare with conventional methods) carburizing process temperature is crucial in programming of carbon diffusion process meaning in process time and final carburized layer characteristics as carbon profile and homogeneity of the carburized layer.