Journal of Environmental Science and Engineering B 9 Mar.-Apr. (2020) 82-86易学英语
doi:10.17265/2162-5263/2020.02.004
Rearch and Follow up of Results on the Reliability Level of Backhoe Loaders
Svetozar Madzhov
Forest Rearch Institute, Bulgarian Academy of Sciences, Sofia 1756, Bulgaria
Abstract: This study identifies the main numerical characteristics of the Komatsu WB93R-5 backhoe loaders reliability indicators. To study the characteristics of the reliability indicators, a methodology for experimental rearch has been developed, using the complex, comparative and formal method, as well as the systematic, cybernetic and statistical approach. This study is a continuation of a study conducted by the author for another period.
Key words: Reliability, maintenance, repair, asmblies, replacement, backhoe loader.
1. Introduction
The study was performed under the conditions in which the machines are operated: a t of natural, climatic, production, technical, economic, organizational and social factors affecting the intensity
of the change of their state parameters. The survey was carried out for the territory of the Republic of Bulgaria in the head office of Kirov JSK in Sofia and Sofia region. The study was performed using the methodology for experimental testing of the reliability level of machines and test plans given in Refs. [1, 2].艾薇儿的歌
2. Materials and Methods
The subject of the study was: 180 backhoe loaders operating year-round, and the nominal working fund was 1896 h per year; 158 h per month. The survey was conducted for a period of 2 years during 2014-2015.
The object of study is the same 180 backhoe loaders surveyed in the previous 4 years for the period 2010-2014. Therefore, the purpo of this study is to prove the results obtained and the findings of the previous study by Madzhov [2].
Corresponding author: Svetozar Madzhov, Ph.D., assistant professor,rearch fields: reliability of mechanization, forest roads.
The source information was collected also at construction companies in southern Bulgaria and includes 42 backhoes. The data collected are from direct obrvations and information cards from January 2014 until December 2015. The data were collected according to the developed methodology of the experimental study, classified by elements and grouped according to the following classification features, properties and reliability indicators [3-7]. The backhoe loaders also participated in the previous study, but 3 more were included in the new period.
The purpo of the study is to determine the basic numerical characteristics of the backhoe loaders reliability indicators, which were the subject of testing using a pre-developed experimental testing methodology. This study is a follow up of a previous study [2], which will confirm the previously obtained results and conclusions, using data of a subquent period, aimed at increasing the result reliability.
The distribution of failures by reason of the failure occurrence (quality of workmanship; design defects; broken rules of operation; continuous operation; normal wear and tear; quality of repair) of the tractor elements is shown in Table 1.
friendship是什么意思The reliability information for the KOMATSU WB93R-5 backhoe loaders was collected over a
two-year period, with a number of information
All Rights Rerved.
Rearch and Follow up of Results on the Reliability Level of Backhoe Loaders
83
Table 1 Distribution of failures by reason of occurrence.
collection forms being completed on an ongoing basis of the period of our survey. For the previous years, the forms were completed on the basis of accounting documents from the archives of the construction organizations, where for each repair or replacement of an asmbly or unit of the backhoe loader it was recorded when it was made, how much fuel was consumed, the price of the asmbly or unit, who the repair or replacement was performed by, for how long, etc. This information was collected for 222 excavators in the two areas. The recurrence for most of the eleme
nts is on average equal to the number of machines, but
there are some elements of tractor units that have not
failed, i.e. they are less than 222. Therefore, we u private methodologies to determine the reliability characteristics of a small sample volume. At the same time, there are items that have failed two or more times, i.e. we have a recurrence greater than 222.
From the analysis of the types of failures due to their occurrence, we find that the largest number of failures is due to breakage of parts and units—56%,
and 44%—due to violation of the regulatory parameters.
3. Results and Discussion
The distribution of the failures of KOMATSU WB93R-5 backhoe loaders in accordance with external manifestation is shown in Table 2.
3.1 Rearch on the Durability of Backhoes Units and Asmblies
The information about the reliability of the elements of the backhoe loader has been procesd on the methods of mathematical statistics [4, 8-12]. The basic numerical characteristics, the parameters of resource allocation of the asmblies and units (exchange elements) of the KOMATSU WB93R-5 backhoe loaders, established on the basis of the experimental study methodology, are given in Table 3, and the gamma percentage resource at = 80%—in Table 4, where a simulation modeling technique developed [2] was ud to determine the basic numerical characteristics of the steering elements.
Table 2 Distribution of failures by external manifestation.
No. External manifestation % of failures
A Broken parts and asmblies 1 Cam shaft bearing 26.2 2 Damage to a gasket tightness 12.8 3 Fuel pump 3.4 4 Check valve spring 4.5 5 Spring of the pusher 3.2
6 Regulator connector 4.9 B Incorrect adjustment parameters
7 Increasing feeding unevenness 15.1
8 Reducing the minimum cycle feed rate 12.2
9 Decreasing the rotation speed and the start of controller activation
7.8
No. Reasons of failures Percentage distribution of failures (%)
1 Continuous operation 48.09
2 Normal wear and tear 9.13
3 Quality of workmanship 9.05
4 Design defects 2.02
5 Broken operating rules 27.06
6 Repair quality 4.65 Total
100
All Rights Rerved.
Rearch and Follow up of Results on the Reliability Level of Backhoe Loaders
84
Table 3 Basic numerical characteristics, resource allocation parameters of KOMATSU WB93R-5 backhoe loaders. No. Backhoe
elements Estimates of basic numerical characteristics and parameters (liters of fuel)
top
(a) (b) V
1 Gear with reduction 19,991 8,000 0.40
2 Gearbox 22,050 10,100 0.46
3 Rear
axle 27,400 9,850 0.36 4 Drive
reducer 26,750 2,350 0.09 5 SU
pump 45,290 14,005 0.31 6 SU
Hydraulics 42,500 15,200 0.47
7 SU hydraulic str. 42,590 15,150 0.36
8 Hydraulic
pump 28,980 12,090 0.45
9 Distribution 25,995 8,750 0.34
10 Hydro
cylinder 25,298 6,155 0.24
11 Compressor 26,298 10,250 0.38
12 Front
axle 16,305 8,205 0.50
13 Generator 22,070 11,150 0.51
14 Control
relay 13,480 6,358 0.47
15 Battery 14,860 65,250 0.44
16 Starter 22,395 10,475 0.47 Table 4 Gamma-percentage resource of the KOMATSU WB93R-5 backhoe loader elements.
No. Excavator element 80% gamma-resource (L)
1 Gear with reducer 11,895
2 Gear
box 14,485
3 Rear
axle 19,890
4 Drive
reducer 33,650
5 Steering unit pump 29,595
6 Steering unit hydraulics 33,295
7 Steering unit hydraulic accelerator 27,105
8 Hydraulic
pump 22,901
9 Distributor 22,948
10 Hydraulic
cylinder 9,465
11 Compressor 13,708
12 Front
axle 7,875
13 Generator 8,975
14 Control
relay 15,995
15 Battery 11,895
16 Starter 14,485
The main numerical characteristics and the law of spare parts requests flow distribution for KOMATSU WB93R-50 backhoe loaders are given in Table 5.
3.2 Survey on the Time for Backhoe Elements Replacement
The study and determination of the time for replacement of tractor elements under the conditions of partial mechanization of repair and maintenance work, the basic numerical characteristics and the co
nditions for replacement of the KOMATSU WB93R-5 backhoe loaders are given in Table 6.
4. Main Conclusions
It was found that the highest number of failures was due to continuous operation of parts and components—48%, and 27% due to breach of the regulatory parameters.
All Rights Rerved.
Rearch and Follow up of Results on the Reliability Level of Backhoe Loaders 85 Table 5 The main numerical characteristics and the law of spare parts requests flow distribution for KOMATSU WB93R-50 backhoe loaders.
No. Exchange
elements
Estimates of basic numerical characteristics (h) хсрσVх (%)
1 Engine 3.95 1.50 37.97
2 Cylinder
head 1.50 1.15 76.67
爱八卦网3 Nozzle 15.00 2.60 17.33
honestly4 Fuel
pump 1.86 1.08 58.96 5 Pump
supp. 1.95 1.00 51.28 6 Oil
pump 4.98 1.35 27.11 7 Water
pump 2.70 1.25 46.39 8 Radiator 1.25 0.59 49.20 Table 6 Replacement time for KOMATSU WB93R-5 Backhoe Loaders’ elements.
No. Backhoe elements Number of workers Replacement time by standard
手工饰品制作
hours (man hours)
Replacement time by expert evaluation (h)
t cp V x
1 Gear with reducer
2 - - 4.25 1.00 0.23
2
Gear
box 2 3.78 (7.56) 9.75 1.24 0.13 3 Rear
axle 2 - - 12.05 1.75 0.15
4
Drive
reducer 2 - - 1.15 0.26 0.23 5
SU
pump 2 1.55 (3.09) 1.45 0.70 0.48 6
SU
hydraulics 2 - - 2.65 0.50 0.19 7 SU hydraulic accelerator 2 1.55 (3.09) 3.65 1.27 0.34
8
Hydraulic
pump 2 1.92 (3.83) 3.05 0.89 0.29 9
Distributor 2 2.30 (4.60) 3.15 0.67 0.20 10
Hydraulic
cylinder 1 - - 0.75 0.26 0.35 11
Compressor 1 - - 1.02 0.25 0.25 12
Front
axle 2 0.63 (1.25) 3.01 0.80 0.27 13
Generator 1 0.27 (0.27) 0.62 0.15 0.24 14
Control
relay 1 0.27 (0.27) 0.55 0.12 0.22 15
Battery 1 0.36 (0.36) 0.15 0.05 0.33 16
Starter 1 0.30 (0.30) 0.78 0.21 0.27
The KOMATSU WB93R-5 backhoe loaders elements resource has been established and is proven to be normally distributed.
The 80% gamma-resource of KOMATSU WB93R-5 backhoe loaders elements with known and unknown distribution law and conci samples has been determined.
The laws of resource allocation of KOMATSU WB93R-5 backhoe loaders elements have been established with the Pearson’s criterion and the basic numerical characteristics are defined.
It has been found that the time for the backhoe components replacement is within a wide range (0.15-12.05h) and this depends on the complexity of the element and the technical equipment with disasmbly and asmbly devices.
References
[1]Madzhov, S. 2020. “Rearch on the Reliability Level of
Backhoe Loaders’ Diel Engines.” Forest Science, Sofia [2]Madzhov, S. 2019. “Rearch on the Reliability Level of
Backhoe Loaders.” Journal of Environmental Science
and Engineering B 8 (4): 134-8.
[3]Kozlovskiy V.A., et al. 1998. Logistics, Sofia. (BG)
actual[4]Mihov, M., and Tav, G. 2012. Machinery Maintenanceforever 什么意思
and Repair. Sofia: p. 149.
[5]Chervonyi, A., Lukyashtenko, V., and Kotin, L. 1972.
Reliability of Complex Systems. Moscow: (RUS).
[6]Mihov, M., and Tav, G. 1990. “Probability Model for
Inventory Stocks Management.” Аgricultural Мachinery
8: Sofia 87-93. (BG)idol是什么意思
All Rights Rerved.
Rearch and Follow up of Results on the Reliability Level of Backhoe Loaders 86
[7]Skovorodin, V., Tishkin, L., and Tav, G. 1990. AM
Reliability Guide. Moscow 245. (RUS)
[8]Spiridonov, G., and Tav, G. 1981. Some Theoretical
and Applied Aspects of the Repair and Maintenance of Agricultural Machinery. Rous: 336.
[9]Kugel, R. V. 1990. Tractor Operational Reliability.
Moscow. (RUS) [10]Mirotin, L. B., 2000. Fundamentals of Logistics. Moscow.
(RUS)
[11]Mihov, M. 1995. “Study of the Distribution of Inventory
Replacement Parts for Tractors.” Ph.D. thesis .
[12]Tav, G. 2000. “Survey on the Structure and Basic
Parameters of the Agricultural Machinery Maintenance System.” Sofia. (BG)
transitAll Rights Rerved.
