Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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2689-0984)
VOLUME
04
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1-13
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(2022:
6.
456
)
OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
ABSTRACT
From analysis of the performance of hydraulic excavators, it has been found that many hydraulic excavators used in
mining operations operate at lower capacities than indicated in the technical description. This can be caused by
unexpected work interruptions, rapid failure of parts, and unreliability of the excavator's working parts.
In this article developments on improvement of cutting elements with increased service life for increase of
productivity of open-pit excavators are resulted. Also, results of experimental tests of the improved teeth of an
excavator bucket are submitted.
KEYWORDS
Quarry, excavator, bucket, tooth, protective element, efficiency, office hours, credibility, rock, abrasive wear.
INTRODUCTION
The efficiency of hydraulic mining shovels depends on
a number of factors, including the climatic conditions
at the location where the hydraulic shovels are
operated, the serviceability of the excavator
Research Article
EXPERIMENTAL RESULTS ON THE EFFECTIVENESS OF AN IMPROVED
EXCAVATOR BUCKET TOOTH DESIGN
Submission Date:
February 26, 2022,
Accepted Date:
March 16, 2022,
Published Date:
March 28, 2022 |
Crossref doi:
https://doi.org/10.37547/tajet/Volume04Issue03-01
Sardorjon Abdumuminovich Turdiyev
Republic of Uzbekistan, Navoi region, Karmana, Bahor str., 39,, Uzbekistan
Rustam Umarhanovich Djuraev
Republic of Uzbekistan, Navoi region, Navoi, Spitamen str., 8 - 21, Uzbekistan
Journal
Website:
https://theamericanjou
rnals.com/index.php/ta
jet
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 04 Issue 03-2022
2
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
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03
Pages:
1-13
SJIF
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(2020:
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)
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(2022:
6.
456
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
components, the reliability of the working parts and
the resistance to abrasion.
Deepening of deposits of minerals in the world, a fact
that mining is carried out in difficult mining-geological
conditions and demands to reliability and economic
efficiency of the existing mining equipment have led to
perfection of a design of working elements of hydraulic
open-cast excavators. The acceleration of open-pit
mining requires the use of modern hydraulic open-pit
excavators and an increase in their capacity. Modern
hydraulic excavators are high-tech, expensive
machines that require important maintenance during
operation. A hydraulic excavator involves a complex
structural system. The rate of wear of the bucket teeth
of quarry excavators today reaches a high level and
remains one of the most urgent problems. The issues
related to the reduction of operating costs during the
operation of quarry excavators, increase of their
reliability, are not solved and urgent now [4].
As mentioned above, an increase in the cost of
operating hydraulic excavators leads to a decrease in
their efficiency.
The analysis of productivity of hydraulic excavators
operated in mineral deposits has shown that the
increase of efficiency of the open-pit hydraulic
excavators is possible on the basis of improvement of
design of their working bodies.
Currently, manufacturers of excavator buckets
produce a wide range of their products, which are
distinguished by improved design of the bucket itself
and its individual elements. Manufacturers offer
several types of bucket protections, depending on the
application, environment, type and size. But the main
factors are simplicity, reliability, durability and relative
cheapness of its construction which is characterized by
competitiveness.
Defects of the cutting elements of hydraulic mining
shovels depend on a number of factors, mainly the
skills of the excavator operator during operation,
failure to comply with operating rules, variability of
rock properties, well blasted large rocks and many
other technical factors.
MATERIALS AND METHODS
Faults in the part of the cutting element of the bucket
of the mining excavator that connects to the adapter
are due to the fact that the adapter and the pin, which
serve to connect the cutting element, are badly
tightened by fitters, special fasteners do not fit, the
fastening pin widens the hole for the adapter.
Failures of HITACHI EX-1200 hydraulic mining
excavators related to bucket cutting elements and
adapter are shown in Fig.1.
Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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VOLUME
04
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OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
Figure 1: Defective part of the HITACHI EX-1200 excavator, connected to the cutting unit and transition part of the
bucket
Failure 1, shown in figure 1, results in additional
resistance during cutting and unloading because the
tines are not fixed to the required standard in the
attachment part of the cutting element and the
adapter part of the bucket. 2 - When the quality of the
cutting element and adapter part fails to harden,
causing the tooth to be in a poor condition and,
consequently, to sink poorly into the rock.
Figure 2: Perforations in the bucket teeth of the HITACHI EX-1200 excavator as a result of erosion:
a - front and side
perforation; б - front perforation; в - side perforation
In many cases, the permissible dimensions of the
bucket cutters are not taken into account in the
operation of quarry excavators. As a result, the teeth
wear out beyond the allowable level and, over time,
holes appear in the teeth (Fig. 2 а, б, в).
Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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OCLC
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METADATA
IF
–
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Publisher:
The USA Journals
Failures caused by untimely maintenance behind the
teeth can lead to even more serious failures in other
systems. Tooth bore research and analysis in
production also leads to rapid wear of the adapter part,
and these processes reduce the efficiency of quarry
excavators and increase operating costs.
In addition, the brittleness of the materials of the
cutting bodies of quarry excavators, the quality of the
preparation process technology and the occurrence of
badly blasted rock during excavation cause tooth
failure due to high stresses in the teeth (fig. 3).
Figure 3: Fracture of the teeth of the backhoe bucket
The analysis of results of the above researches shows,
that most of defects of teeth of quarry hydraulic
excavators, used at surface mining works, do not
possess necessary durability and longevity of bucket
teeth, i.e. they quickly lose their properties, under
influence of various minerals quickly become
impassable, that leads to failure of other parts of
quarry excavators and to drop of operational
characteristics [3].
Taking into account above-stated, at carrying out the
development of technical solutions on increase of
durability, service life and efficiency of cutting
elements of buckets of mine excavators is the actual
problem.
Teeth are the main wearing parts of bucket and they
can be replaced when they are worn out, that extends
the life time of bucket. Modern tines consist of an
adapter welded to the bucket and the tines are easier
to replace with a pin if needed.
Studies have shown that as excavator and loader
cutters wear out, their productivity decreases
significantly, changes in cutting edge geometry
adversely affect their efficiency and increase the
duration of excavation work [1].
It has been
proved that power consumption in excavation works
with blunted cutting edges is 1.5-2 times higher than
with new cutting edges. Practice of using of excavator
buckets has shown that allowable for wear of teeth
increases specific shift load by 50-100 % in comparison
with cutting conditions with teeth of nominal shape
Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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VOLUME
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6.
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OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
and size. Failure of cutting elements of excavator and
loading machines significantly affects their working
capacity. In some cases, due to wear of the working
part, machine productivity is reduced by up to 40 % and
fuel consumption increases by up to 30 % [2].
THE MAIN PART
There are several types of bucket teeth of hydraulic
open-pit excavators, which are used as a base teeth of
hydraulic open-pit excavators operating in all open pits
of JSC "Navoi Mining and Metallurgical Plant" of the
Republic of Uzbekistan, pictures of these teeth below
are shown in Fig. 4 и 5.
Figure 4: Schematic drawing and three-dimensional view of a standard bucket tooth
The average service life of this type of bucket teeth
currently averages between 12 and 14 days. The time
required for each replacement reduces the efficiency
of the excavator, and prolonged failure of the teeth
leads to higher operating costs.
Thus, in order to increase productivity of hydraulic
excavators, it is important to create anti-slip tine
shapes and develop and select effective technological
methods to improve their durability.
Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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04
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OCLC
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METADATA
IF
–
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Publisher:
The USA Journals
Figure 5. Three-dimensional view of the improved excavator bucket teeth
Theoretical researches and observations of the cutting
elements usage in the production process showed the
necessity to increase the strength of the upper and
lower surfaces of the bucket teeth that are in the most
contact with the rock. For this purpose special notches
for standard bucket surfaces, and also some improved
types of bucket teeth for increase of efficiency of
surface excavators at the expense of increase of
resistance of cutting elements to abrasion have been
developed.
For the purpose of increase of wear resistance and
service life of bucket teeth we have developed the new
design of a tooth containing lozenge-like relief pattern
on its surfaces, the drawing of which is shown on fig. 5
и 6.
Volume 04 Issue 03-2022
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(ISSN
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VOLUME
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METADATA
IF
–
7.856
Publisher:
The USA Journals
Figure 6. Appearance and dimensions of the bucket tooth design of the improved diamond-shaped relief tooth: a -
top view and dimensions; b - side view and resolution
The improved bucket tooth design differs slightly from
the basic design in terms of structure and dimensions,
while the material remained unchanged.
With the improved tooth design, special relief patterns
were formed on the top and bottom of the entire div.
The total length of the developed tooth was 36.0 cm
and 5 lozenge-shaped relief patterns were formed on
the upper and lower surfaces of the tooth along the
tooth length of 27.2 cm, forming a strong abrasion due
to high loads in contact with the rock.
In order to determine the effectiveness of the new
design of teeth of the developed excavator bucket,
their experimental tests were conducted.
During the experimental work of the new teeth, their
resistance to abrasion, that is, their working life, was
investigated.
The experimental tests were conducted on the open-
cast hydraulic excavator HITACHI EX-1200 at "Auminzo-
Amantaytau" mine of the central mine administration
of Navoi mining-metallurgical combine JSC.
Volume 04 Issue 03-2022
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The American Journal of Engineering and Technology
(ISSN
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VOLUME
04
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(2022:
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OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
The experimental tests were conducted in the
following way, at the first stage of tests with the
installation of basic teeth on the excavator bucket the
loaded rock and semi-rock with the strength f = 12 ÷ 14
was excavated. During the conducted experimental
tests, the length of the bucket teeth and the average
thickness 5 of the detachable parts were determined
by wear during their operation for a certain time (Fig.
7).
Figure 7: Arrangement of the cuts for which the wear value of the base tooth is measured:
z
1
, z
2
, z
3
, z
4
, z
5
are the
ordinal numbers of the cuts on the flat surfaces
In experimental tests, one of the most effective
differential methods was used to determine the
change in bucket teeth dimensions due to friction
along its length and disconnected parts within a certain
time interval, using a caliper of Shtz-400 type with a
measurement error tolerance of Δl = 0.1 mm and the
results are shown in Table 1.
Table 1
Wear rates of the bucket's base tooth as a function of operating time
Volume 04 Issue 03-2022
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Publisher:
The USA Journals
Т, moto-
hours
L, mm
Δl,
mm
Z
1
, mm
Z
2
, mm
Z
3
, mm
Z
4
, mm
Z
5
, mm
0
360
0
40
81
103
143
174
30
332
28
33
79
102
142
173
60
308
52
-
76
100
140
171
90
286
74
70
98
137
168
120
264
96
64
95
134
165
150
249
111
-
91
131
162
180
235
125
85
128
159
210
221
139
78
124
156
240
210
150
72
119
153
270
196
164
65
114
150
300
180
180
-
108
147
where, T - operating time, moto-hours;
L - tooth length, mm;
Δl - wear value, mm.
The following experimental tests were carried out on
five teeth in a lozenge-shaped relief pattern, which
have been refined. (Figure 8).
The diamond-shaped relief patterns and flat wear
rates over time were measured in the five areas shown
in Figure 8 and the results are shown in Table 2.
Table 2
Wear rates of the improved bucket tooth as a function of operating time
Volume 04 Issue 03-2022
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(2022:
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METADATA
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–
7.856
Publisher:
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Т, moto-
hours
L, mm
Δl,
mm
Sections 1
Sections
2
Sections 3
Sections 4
Sections 5
Z
1
mm
Z
1б
Mm
Z
2
m
m
Z
2б
mm
Z
3
m
m
Z
3б
mm
Z
4
mm
Z
4б
mm
Z
5
mm
Z
5б
mm
0
360
0
35
45
76
86
98
108
138
148
169
179
30
346
14
32
38
75
85
97
107
138
147
169
179
60
329
31
28
30
74
84
96
102
137
146
168
178
90
318
42
-
-
72
82
95
98
137
146
167
177
120
306
54
70
80
94
96
135
145
166
175
150
293
67
68
78
92
94
135
142
164
173
180
286
74
65
73
90
92
132
140
162
171
210
273
93
63
65
87
89
130
138
161
169
240
248
112
-
-
84
87
128
136
159
167
270
237
123
80
82
125
134
157
165
300
226
134
76
78
121
131
156
163
330
214
146
72
74
117
126
154
160
345
203
157
68
70
114
122
152
157
360
191
169
64
66
111
111
150
151
375
180
180
-
-
108
108
147
147
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(2022:
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OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
Figure 8. Location of sections for which the wear value of improved teeth is measured:
z
1
, z
2
, z
3
, z
4
, z
5
- ordinal
number of flat surfaces of sections; z
1b
, z
2b
, z
3b
, z
4b
, z
5b
- ordinal number in the arrangement of diamond-shaped relief
patterns on sections
EXPERIMENTAL RESULTS
Based on the analysis of the results of the experimental
tests conducted to determine the effectiveness of the
improved design of excavator bucket teeth, it is found
that the service life of the bucket teeth depends on the
wear value.
Based on the results of the above experiments, the
dependence of the service life of the excavator bucket
tooth of the basic design on the wear value is shown
graphically in Figure 9 below.
Figure 9. graph of the wear rate of the bucket's base tooth as a function of operating time
0
20
40
60
80
100
120
140
160
180
200
0
50
100
150
200
250
300
350
W
o
rk
in
g
tim
e
,
T
(
m
o
to
-
h
o
u
rs
)
Wear rate, Δl (mm)
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)
OCLC
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METADATA
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–
7.856
Publisher:
The USA Journals
As it can be seen from the graph of the base bucket
tooth's operating time versus the wear value in Figure
9 above, there is an increase in the wear value of the
tooth as the excavator's operating time increases.
Thus, as a result of increase of operating time every 30
hours the value of wear on the length of the bucket's
basic tooth was 22-28 mm in the initial hours of work of
the tooth, i.e. up to 150 hours of moto-hours. During
the next 150-300 moto-hours of operation every 30
moto-hours, the amount of wear on the tooth length
was 11-16 mm.
The excavator's operating time for the permissible
length of the bucket's basic tooth was 300 engine
hours.
The results of the performance of the new excavator
bucket tooth designs developed during the
experimental and test work were also recorded, and
based on these results the dependence of the
operating time of the 5-rhombic excavator bucket
tooth shape on the wear size was established, and this
dependence is shown in Figure 10 below.
Figure 10. Flowchart of the wear rate of the improved diamond shaped bucket teeth versus operating time
As can be seen from the graph of the working time of
the improved bucket tooth and the wear value, shown
in Figure 10 above, there is an increase in the wear
value of the tooth as the operating time of the
excavator increases. Thus as a result of increase of
operating time every 30 hours the value of wear on
length of the bucket's improved tooth was 11-18 mm
during the initial working hours of the tooth, i.e. up to
150 hours. During the next 150-360 hours of work every
30 hours the amount of the wear was 11-16 mm on the
length of the tooth.
The operating time of the excavator for the permissible
length of the improved five diamond-shaped relief
teeth of the excavator bucket was 360 moto-hours.
CONCLUSION
Based on the results of experimental studies, graphs of
wear length from operating time of basic bucket tooth
and the improved five lozenge-shaped relief bucket
teeth have been established and their mutual
correlation has been developed (Fig. 11).
0
20
40
60
80
100
120
140
160
180
200
0
50
100
150
200
250
300
350
400
W
o
rk
in
g
tim
e
,
T
(
m
o
to
-h
o
u
rs
)
Wear rate, Δl (mm)
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)
OCLC
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METADATA
IF
–
7.856
Publisher:
The USA Journals
Figure 11. Lifetime relationship graph for basic and advanced five rhombic relief teeth: 1 - basic tooth; 3 - five
rhombic relief teeth
Basis shown in Fig. 11 from the above graph of the
dependence of the value of longitudinal slippage on
the operating life of the 5 diamond-shaped relief teeth
of the bucket, it can be seen that the improved
operating life of the 5 diamond-shaped relief teeth in
comparison to the basic bucket tooth is 60 hours, i.e.
20% more time of performance detection.
REFERENCES
1.
Gavrishev S. E. Rationale of organizational and
technological methods for increasing the reliability
and efficiency of open-pit mines: Ph: -
Magnitogorsk, 2002. - 294 pt.
2.
Poderny R.Y. Analysis of the current state of the
quarry machinery market in the world // M.: Mining
Industry, 2013. - №4 (110).
3.
Turdiyev S.A and Jurayev A.Sh 2022. Study of the
effect of excavator bucket tooth abrasion on
digging resistance. Academic Research in
Education Sciences. 3(3), pp. 105-110.
4.
Abduazizov N.A., Mahmudov Sh.A., Turdiyev S.A. A
study on the theory of the work of the working
elements of hydraulic quarry excavators. Bukhara
Engineering Technologists University. Discipline
and technology development of a scientific and
technical journal. 2021 il 3rd p.4-11.
0
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0
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1
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