Researches of the combined coulter working process for direct strip sowing of seeds

. In this paper We presented design of analytic dependencies of main geometrics parameters of combine coulter distributer for direct strip sowing of cereals with accounting of pass speed of particle from the distributer.


Introduction
More perspective direction for conditions of the Russian Federation is development seeder of direct sowing with passive working bodies if we will take in account higher reliability in working, relatively simple construction and accordingly, the lower cost in manufacturing and in purchasing by the agricultural producer. At the same time, combined working bodies for direct sowing of cereals are perspective. They ensure the uniform distribution of seeds over the feeding area. Researches of justification of the main parameters of the combined coulter of the direct sowing seeder are actual tasks especially for ensuring high-quality strip sowing of cereals in compliance with agrotechnical requirements for zero tillage [1][2][3][4][5][6].

Material and methods
In the strip sowing, one part of the seeds enters to the soil through the seed tube 2 in the central part of the coulter, and other seeds scatter across the soil with a distributor in duckfoot sweep 1, which forms the seeding strip Figure. 1.
For this function, It is necessary to find the geometric correlation between the constructions elements of the distributor for a given sowing strip width bn, the transverse dimensions of the seed tube outlet pipe: length Lc and width bс, dihedral angle 2γ at the top of the distributor, clearance ∆h between the lower edge of the distributor and the soil , subsweep height Hс Figure. 2.
We chose such defined parameters of the distributor: the distributor width (bp, the length of the rectilinear section of the distributor surface Ln=АВ, the length of the curved section of the distributor surface LК=ВС, the radius of the curvilinear area circle of the distributor surface R, the angle of inclination of the edge δ to the longitudinal axis of the coulter, central angle α of the generatrix of the curvilinear area, the height of the distributer top Нр , the distance hо from the soil surface of the center of the circle of the curvilinear area of the distributor surface (point О) and the distance lо from distributor axis to the specified center.
It was made mathematical analysis of the association of the geometric distributor parameters in accordance with the calculation scheme. Figure. 2.

Fig. 1.
Combined coulter scheme: 1 is duckfoot sweep; 2 is seed tube; 3is opener stand; 4, 5 are hole for mounting the coulter; 6, 8 are mounts for a circular knife; 7 is stand of a circular knife; 9 is a fork of a stand of a disk knife; 10 is circular knife.

Results and discussion
Space between the rectilinear area AB and the seed tube can be selected according taking into account the grain particle length, i.e. М1М=lz., for free passage of a grain particle with length lz to a curved linear area of the BC surface. Then the horizontal projection ММ2 of the indicated segment from ∆ММ1М2 is equal to γ cos 2 z l ММ = . (1) According this, the magnitude of the horizontal projection of the rectilinear generatrix area АМ2, is determine by equation (2), which located inside the seed tube γ γ γ cos 2 2 cos cos 2 And Its vertical projection -interval АА1, is equael: Then distance from the distributor top (point A) to the soil surface is determining by dependence: В ∆СD1D hypotenuse of the SD is coinciding with the particle flight trajectory when its leaving the distributor at the speed Vc. With this in mind, the particle motion time tz can be determined according to the free-fall law of a moving particle from the height of SD1 = Δh in the SD section.
From the physics course it is known that in this case 2 From the triangle ΔDSD1 it follows that: But from a comparison of the angles ∟СОК and ∟ДСД1 it follows that Then parameter bр is determining from rule (10) Taking into account ∆OBK1 and ∆OCK, it follows from the geometric scheme that In view of (12) and (13), expression (11) takes the form and In view of (6) and (16), expression (15) takes the form Thus, we obtain the system of equations (14) and (17) From the first equation of the system we express ln: Substituting (19) into the second equation of system (18), we have From where it follows that (21) From ∆ABB1, the length of the rectilinear section Ln=АВ, taking into account (19) It follows from (7) In view of (8) and (23), the parameter ho is expressed by the following dependence