Education of the republic of uzbekistan tashkent state technical university named after islam karimov

Mechanical Engineering
235 
A more accurate but more labor-intensive method (the method of recording pulses 
separately) was applied to the initial region of the rising network of coupling characteristics. The 
sliding speed was determined by the displacement of the pulses. 
The adopted method made it possible to measure the relative slip speed in the range of 
0.1 to 100%. In total, approximately 2,000 points were obtained to construct the relationship 
sought during the tests. 
EXPERIMENTS TO DETERMINE THE COEFFICIENT OF ADHESION. 
In the 
processing of experimental data, N. N. By combining the first two branches of the Menshutin 
conjugation description into a single conditionally growing branch 
А



0
and that 
A
u
u

0
. 
He divided the network into two sections and proposed the following analytical dependencies for 
them (sandless motion) (expressed as a percent): 
5
,
0

K
k
a
28
,
0

for the case; 
5
,
0
1


K
k
k
36
,
3
5
,
3
196
,
0
155
,
0




for the case 
1

k
, 
%
5
,
2

a
when this is the sliding speed 
A
u
and when it exceeds it, the coupling 
characteristic shifts to a decreasing network. Experimental data show that, in fact 
1

k
case 
equals
%
4
,
1
2
,
1
0


a
. 
It is known from the formulas and experimental data that when present, the current value 
of the coupling coefficient increases linearly with increasing slip speed. 
%
14
,
0

a
is 

The 
growth rate of s slows down, while its value approaches asymptotic 
0

. In the range of 0.8 to 
1.4% of the values, the value of ps increases from, 
a
of the following 
%
5
,
2
0
,
2


A
a
maintains 
a constant value in growth up to. 
Sliding speed 
А
u
This is when the zone of full or excessive slip along the rails of the 
wheel begins 

associated with a decrease in. From the analysis of the experimental data, it 
became clear that the current value 

in the growth of 
изб
u
The dependence on can be expressed 
by a simplified empirical formula in which the final value increases 
)
(
1
1
A
А
А
u
u






, (3) 
Where is 

А

А stiffness of the adhesion characteristic at the point. In this regard, the 
clutch description is divided into two sections: the productive of the wheels (
A
u
u

) and 
complete (
A
u
u

)sliding areas. The following is for the full sliding section 


du
d
A



The 
stiffness parameter of the coupling characteristic is important, it is its ultimate slip speed 
А
u
with a higher magnification than determines the shrinkage intensity of 

.
Based on a large amount of experimental data [6,11] 
À

size (value) was found to 
decrease with increasing v
. 
According to foreign tests, 
90
70



km/h 
it is possible to indirectly assume that the
А

value decreases to about 0.25 m / s at km / h.

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