THE ANALYSIS OF OPERATIVE PARTS OF A MINI ROTARY CULTIVATOR

M. Mamuladze 1 and N. Beridze 2 . 1. Associate Professor, Batumi Shota Rustaveli State University. 2. Assistant professor, Batumi Shota Rustaveli State University. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


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Ghosh model-A dimensional analysis of the torque requirement under different operating conditions was performed by developing a dimensional formula using the angular velocity of the rotor, the depth of working, the velocity of travel, the soil bulk density, the soil cohesion, the acceleration due to gravity and the soil particle size as independent variables. For a given soil, the moisture content and compaction conditions in the field, the forward speed of travel, are related in a dimensional equation: Gupta model-Based on the predicted behavior of saturated soil under impact loading and pure shear, amathematical model to predict the power requirement of a rotary tiller has been developed. The torque required by a rotary tiller is based on the following operations. The impact cutting of the saturated soil by the rotary tiller initially starts with compression. When the cutting speed is high, compression is very quickly followed by impact shear.
Force required to cut the soil in (3):-Where represents the impact shear stress to cut the soil. is the total wetted area of the cutting surface of the tool, in mm2, and -is given by the equation.

Where
-mass of the soil slice in kg, P-tilling pitch in mm and -specific weight of the saturated soil in N/ (3) Torque required to overcome soil-metal friction Normal force N that acts on the tool is equal to weight of cut soil slice given by ( ) Force required to overcome soil-metal friction is given by ( )
During cutting with the rotary tiller, the cut soil slice is separated from the uncut soil by pure shearing or soil-soil sliding. Equation 9 describes the behavior of the saturated soil under pure shear, according to the experiments conducted in a coaxial viscometer.
The shearing rate is a function of the speed of rotation of the blade and the depth of working: Substituting the value of into Eq. 9, yields, The attrition of blades depends on the quality of the material from which they are made, their solidity, the emulsion with which they are sprayed, the heat treatment undergone, their depth, toughness and shape, the cutting angle, the edge of the blades, their curvatures, and the angle of scoop. The attrition of a blade is correlated with mechanical output forces, the arrangement of the tiller blade, the repeated crushing of the soil, and other factors. The operating conditions also depend on the tilling area, the compression of the soil, the impact loads, the resistance due to abrasion and sharpening The geometry of tiller blades is considered to be the most important factor in their design because both the shape of the blade tip and the lengthwise of the tiller blades facilitate cutting. The width of the blade tip exceeds the lengthwise of the blade. The contact between the blade and the soil moves slowly from the handle near the center of the shaft to the length of the blade. The tip of the blade at the boundary between the lengthwise of the blade and the blade tip cuts the intact grass. The grass can also be thrown away or torn off by the outward rotation. This type of blades performs well in the soil in Evrope and is extensively used in Georgia. Figure 2 shows both the blade tip and the lengthwise of the blade, as segments ED and Dn, respectively in Fig. 3. The lengthwise of the blade must meet two conditions. One is the absence of intertwisting and the other is a low drag force during cultivation. The cutting conditions are (Fig. 2).

( )
Where is the friction angle of the rootstock with respect to the blade edge. The lengthwise of the blade is part of an Archimedean curve whose parametric equation is, where -initial blade helical line radius, in cm -otation radius of the blade, in cm -maximum tilling radius, 24-26 cm -thickness of soil in transverse section, in cm -maximum depth of working, in cm -maximum central angle，35-45° T-cutting force, in N F-friction force, in N Take i as the angle between AA' and line Om; ( ) The angle i increases with the angle , but the angle decrease, as determined by graphical analysis. The low positively affects the cutting work.Equations (14), (15),and (16) present anotherclosed solution (Sakai et al., 1976;Sakai, 1978) whichcan be obtained using polar coordinates on the spiralline (Figure 4). These equations have the same meaning as Eq. (13).
aximum radius at the tip point of the edgecurve, in cm edge-curve angle at the tip point where r is maximum -calculated radius of the spiral, in cm -forward speed of travel, in cm/sec -4° or great than First, use Eq. (17) to calculate angle β (Fig.3) Angle can be easily found by using Eq. (18). First, use Eq. (17) to calculate angle β (Fig.3) Angle can be easily found by using Eq. (18). 915

Conclusion:-
This study establishes and analyzes mathematical models of the plowing force and orientation curve of tiller blades and cultivation blades. To ensure good efficiency and uniform resistance of the plow to soil, the blade must be protected from intertwisting. The theoretical and calculated cutting angles are 85.88° and 85.10° and, the edgecurve angles are 55.00° and 56.18°, with the data in the literature. The rear of awell designed plowing blade does not cause any friction with the soil. The curve of plowing shows that when the relief angle of the tiller blades is 25°, the turning and the throwing have good performance. When the relief angle of the plowing blade is 10°, the impact force and the crashing force of the blade into the soil will be minimized during plowing.