Novikov A. The rise of the resources of the cutter development machine Dissertation

Nowadays coal industry should solve the problem of coalmining intensification from lava. It means per capita power consumption increases and therefore the rotation speed of operating member increases too. It leads to tensions increase acting in the cutting tools, so tools-lifetime decreases. Thus, lifetime increase of cutting tools is one of the most actual problems of mining mechanical engineering.

The aim of this work is increase of the margin of safety of drifted combine’s cutter with planetary operating member that helps to increase cutting tools lifetime.

3. The regularities of formation of shavings parameters and kinematical changes of cutter’s angle of PIO.

Explanation of material and its results. For general formulation solving by shear parameters’ and kinematical changes of cutter’s angles determination the scheme of pit face processing of PIO was used. (picture 1).

Picture 1. The scheme of pit face processing of PIO of combine like Ural-10KS

On the picture the following symbols are used:
V_под – the gear of OM rendering for pit face
ω_в – angular velocity of reducer’s rotation and OM driving gear (bulk motion)
ω_д – angular velocity of cutting disc’s rotation
d_д   – cutting disc’s diameter by cutter’s tops
С – distance from axle rotation of OM to axle rotation of cutting discs (radial displacement of OM axle)
А – side displacement of cutting disc’s axle
D_заб   – diameter of starter
D   – diameter of OM
R_в – radius of carrier
е – distance
φ – i-go cutter’s angular position
φ_вх – angular entrance into cutting tool’s contact
φ_вых – angular exit from the cutting tool’s contact
х, у, z – coordinates of cutting tool in space
Taking into account this picture the thickness and width of shear in cutter we can determine by dependences

Where is    пв – the rotation frequency of carrier;
пд – the rotation frequency of cutting disc;
z_д– the number of cutters on cutting disc;
φ –  angle of cutter’s position by disc rotation;
кд –  number of cutting discs on one OM.
Side gear of cutter’s displacement (picture 2) can be determined by dependence

Where - the radius of cutter’s turning by its bulk movement

Picture 2 - components of gear and travels of cutter’s top

The components of this gear ( the gear of side cutter’s rendering and its vertical travel can be determined by dependences:

The meanings of kinematical changes of cutter’s back and side angles

For the combine Ural-10KS using the package “Math CAD” the meanings of thickness and width of shear in cutter and kinematical angles of cutter from angle’s turning by its rotation were counted. By these calculations the next parameters of combine’s OM were used: V_под=20 м/ч; п_в=4,74 об/мин; п_д=41,57 об/мин; z_д=12…18; к_д=2; φ=0…180°; d_д=1,04 м; А=0,43 м; С=0,89 м.
With the package “Math CAD” using the results of calculations the dependences shown on picture 3 were made.

The analysis of this dependence shows that the thickness of shear changes by sinusoidal law and receives the greatest meaning by φ=90, in this case h reaches 3,5 sm.

Analyzing shear thickness’ attitude towards width t/h for the greatest meaning of angle’s turning the changes from maximum to minimum is observed and the constancy is observed by the small meaning t/h.
Taking into account all that have been said it is necessary to diminish the cutter’s loading and increase its reliability. One of the decisions is the valuation of forces acting on cutting tool and increase of margin of safety.
Solving of this task was made by the way of building the volumetric cutter’s model with the help of applied program ANSYS (picture 4).
The next steps were:
- the destination of necessary material with its physical parameters for the every element of model.
- the crash for the net in the form of tetrahedrons of definite sizes for receiving accurate results.

- the application of necessary forces and limitations acting on the cutting tool (picture 4).
The construction was simplified by the following way – the part of fixed in the cam cutter wasn’t designed because it is fastened in the cam very hard and exertions acting from the forces will be unimportant. The forces wee done for the cutting edge at three projections; the meaning of each component is 1 ton. Also the limitation was done for the lower part of cutter. After this the calculation was done by the method of final elements.

Analyzing the calculation result (picture 5) we can say that the tensions appearing in the stated area A form 865 MРа begin to grow that leads for the further disengagement of cutting plate.
Also the most influencing on the formation of so high tensions force was determined. It is the side power.
By applying of one of the side powers the tensions in the area A were 745 MРа (picture 6).

In the course of work the new cutter’s construction shown on the picture 7 were suggested and counted taking into account one side power. The calculation result is shown on picture 8, here we can see that the meaning of equivalental tensions from side component in area A are diminished and now they are 550 MРа.
We should decide which of the sizes will be optimum. For this aim we build diagram “the tension dependences from groove’s depth” (picture 9). From this diagram we can see that the most optimum result is b=6 mm, a=10mm.

4. The directions for the further researches.

From the calculations it is shown that tensions were diminished into 1,5 times therefore the lifetime of cutting tool was increased. The direction for the further researches is founding of new models for reducing of acting tensions.

to beginning

Novikov Anton

Speciality: Mining machines

Group: MASH-07м

e-mail: nolvikov@mail.ru

Theme of final work: "The rise of the resources of the cutter development machine with the planetary industrious element"

Scientific adviser: k.t.n. professor Semenchenko Anatoliy

Dissertation