Investigation of the Strength Parameters of Drilling Pumps during the Formation of Contact Stresses in Gears

The relevance of this research lies in the need to develop scientifically based methods for calculating and designing a transmission shaft with a hardened coating of increased strength and service life of a core drilling pump drive that can allow for a redistributing of resistance forces along the contact surfaces of the gear. This relevance is confirmed by the need to improve domestic methods for designing drive shafts of increased reliability which can ensure the development of frozen soils during deposits exploration. The purpose of the research is to increase the energy efficiency and service life of the high-loaded drive gear teeth of core drilling pump transmission shafts by justifying the critical loads and stresses in hardened gear coatings acting under intense wear of the contact surface with a broken contact symmetry. The criteria for the effective wear area with an uneven contact cross-section at the maximum bending moments of the transmission shaft of the drilling pump were justified and presented in the work. Additionally, the process of interaction of the transmission shaft gear teeth with the eccentric shaft gear at uneven axial torques was investigated. The effective power (Ng) of the gearing of the drive transmission shaft gear and the eccentric shaft gear, which characterizes the energy consumption of the drill bit depth stroke, was justified. This work also proposes a method of substantiating the technological and power parameters of the transmission shaft by using Legendre polynomials. A nomographic chart was developed for the determination of the dependence of the contact stress base cycles on the change in the load distribution factor and the contact spot deviation factor from the design axis λ.

Drudgery reduction in operation of cleaner-cum-grader: An ergonomic intervention

A pedal-operated cleaner-cum-grader having common bicycle chain-sprocket mechanism to get the speeds of 240 and 720 rpm of eccentric shaft and blower shaft, respectively for the desired cleaning/grading of grains was developed earlier by CIAE, Bhopal. Also, in order to utilize the human energy in more efficient way through pedalling mode, CIAE has recently developed a dynapod. The dynapod is a pedal operated rotary device, which can be used as an interface between human worker and any rotary-type machine. The developed dynapod was used to operate the cleaner-cum-grader to assess the drudgery reduction in its operation in comparison to original pedalling mechanism. The dynapod was interfaced with the cleaner-cum-grader by carrying out minor modifications in the original unit. Eight male agricultural workers with mean stature and weight as 168.4 cm and 54.4 kg, respectively participated in the study. The cleaner-cum-grader was used for cleaning and grading of soybean grains. Heart rate of the workers was measured during operation of cleaner-cum-grader using the dynapod as well as the original pedalling mechanism. Mean working heart rate during operation of machine with original pedalling mechanism was 114 beats min-1 as against 108 beats min-1 in case of pedalling with dynapod. The work pulse (ÄHR) with the original pedalling mechanism was 35 beats min-1 as against 29 beats min-1 during pedalling with dynapod. The output capacity of the machine increased from 303 kg h-1 in case of original pedalling mechanism to 345 kg h-1 with dynapod. Considering the cardiac cost as well as output of the machine, the drudgery reduction by using dynapod with cleaner-cum-grader was about 25.4% as compared to the original pedalling mechanism.

Characterization and Functional Evaluation of Surface Texture of Micro Eccentric Shaft Based on Multi-index

Micro eccentric shaft has important application in many high-tech fields because of its small specific gravity, material and energy saving. The surface texture generated during processing has an indispensable influence on the surface integrity and the final functional capability. However, due to the micro scale and weak rigidity, it is difficult to characterize the surface texture and evaluate the functionality by traditional quantitative parameters. In order to comprehensively realize the surface texture characterization and functional analysis, a mathematical model is established to analyze the surface texture machined with different cutting tools. AnchorThe machining deformation of the micro eccentric shaft machined during turn-milling with different cutting tools is compensated. Then the surface microscopic profile and functional performance of the surface texture are analyzed by amplitude distribution function (ADF) and bearing area curve (BAC), and the surface texture is also evaluated by fractal dimension, which can avoid the effect of scale and resolution. Furthermore, power spectrum density (PSD) is utilized to analyze the relationship between the process dynamic state and geometrical specification of the surface texture. It is shown that the microscopic height distribution of surface machined by flat end milling cutter tends to be more random and there are more microscopic geometric features than that of the ball end milling cutter. The machined surface obtained by the flat end milling cutter has better load bearing, wear resistance and liquid retention capability.

SIMULATION OF FORCE ACTION ON OSCILLATING PLOUGHSHARE OF HARVEST MACHINE

The dynamics of the drive of the digging mechanism with oscillating ploughshare is investigated. To determine the input impact, a model of the ploughshare-soil interaction process is proposed, based on which the axial forces in the ploughshare connecting rods and moment of resistance on the eccentric shaft are calculated. To verify the adequacy of the model to the experiment, the analytical axial forces and the moment of resistance were compared with the force dependences obtained as a result of tensometric tests. Small oscillations in the drive are investigated on the basis of linear dynamic model. Analytical and empirical functional dependences of the amplitudes of the torques from the oscillation frequency of the drive, operating speed, and ploughshare installation depth are obtained.

Static force analysis of a single toggle jaw crusher

There are various recommendations in domestic and foreign literature regarding the law of distribution of the crushing load along the swing plate of jaw crushers: even, linear or nonlinear. The method of load distribution along the swing jaw affects the resultant crushing force, its application point and, therefore, the forces subjected to the jaw crusher links. A feature of a single toggle jaw crusher is the strong force exerted on the eccentric shaft since the crushing forces are directly transferred to the shaft. Therefore, it is important to determine the worst design case in order to calculate the strength of crusher parts. This article represents the static study of the influence of the application point of the crushing force on the forces acting on the eccentric shaft and the toggle plate of the single toggle jaw crusher. During the study, a kinematic scheme of the mechanism of the single toggle jaw crusher in the form of a four-link crank mechanism was worked out. The dependences of the angles of the rotation of the link on the angle of the eccentric shaft rotation of the crusher were obtained, which allowed determining the trajectories of different points of the swing jaw and the sections of the moving plate which crushed feeding material during the cycle. Static force analysis of the mechanism of a single toggle jaw crusher was carried out which made it possible to understand the mechanism of torque transmission to the links of crusher, determine the forces acting on the toggle plate and the eccentrics shaft bearings, as well as the shifting of application point position of the resultant crushing force along the swing plate during one stroke. The graphs of dependencies of the forces acting on the eccentric shaft and the toggle plate on the position of application point of the crushing load were built, which made it possible to determine the worst case for calculating the strength of crushers’ joints. It is established that maximum forces subjected to the eccentric shaft and the toggle plate occur when the crushing force is applied to the bottom zone of the moving plate. Such an application corresponds to the nonlinear distribution of the crushing load along the swing jaw.