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1
Content available The influence of kinematic viscosity of a lubricant on broadband rolling bearing vibrations in amplitude terms
100%
Jakubek B. , Barczewski R.
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2019
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tom Vol. 20, No. 1
93--102
EN
Long and trouble-free operation of rolling bearings is largely dependent on their lubrication. Depending on their properties, lubricants reduce the levels of vibration and noise generated by a running bearing to varying degrees. Such an influence of the lubricant is usually desirable during operation. On the other hand, from the point of view of post-production diagnostics, which uses vibroacoustic (VA) signals to evaluate the quality of bearings, lubricants can lead to unwanted masking of damage and manufacturing defects. This is due to a decrease in amplitude and/or a change in the spectral composition of the vibrations. Studies on the influence of lubricants on bearing vibrations were carried out on a set of 10 new tapered roller bearings using 12 oils of different kinematic viscosity. On the basis of the test results, the influence of oil viscosity on the level of vibrations generated by bearings and the nature of this relationship were determined. The sensitivity of selected measures of acceleration of bearing vibrations to changes in viscosity of the lubricant used was determined in this paper. On this basis, the premises concerning the criteria for selection of a lubricant for the purpose of post-production diagnostics of rolling bearings were specified. Appropriate lubricant parameters have been defined to guarantee the stability of the rolling bearing testing process and to reduce the masking of manufacturing defects in the VA signal.
XX
Długa i bezawaryjna praca łożysk tocznych w dużej mierze uzależniona jest od ich smarowania. Środki smarne, w zależności od swoich właściwości, w różnym stopniu obniżają poziomy drgań i hałasu generowanego przez pracujące łożysko. Takie oddziaływanie środka smarnego jest zwykle pożądana na etapie eksploatacji. Natomiast z punktu widzenia diagnostyki kontrolnej (poprodukcyjnej), wykorzystującej sygnały wibroakustyczne (WA) do oceny jakości łożysk, substancje smarujące mogą prowadzić do niepożądanego maskowania uszkodzeń i wad produkcyjnych. Wynika to z obniżenia amplitud i/lub zmiany składu widmowego drgań. Badania wpływu środka smarnego na drgania łożysk przeprowadzono na zestawie 10 nowych łożysk stożkowych z zastosowaniem 12 olejów o różnej lepkości kinematycznej. Na podstawie wyników testów określono wpływ lepkości oleju na poziom drgań generowanych przez łożyska oraz określono charakter tej zależności. W pracy określono wrażliwość wybranych miar przyspieszeń drgań łożysk na zmiany lepkości stosowanego środka smarnego. Na tej podstawie sprecyzowano przesłanki dotyczące kryteriów doboru środka smarnego na potrzeby diagnostyki kontrolnej (poprodukcyjnej) łożysk tocznych. Określono parametry środka smarnego gwarantujące stabilność procesu testowania łożysk tocznych i przyczyniające się do ograniczenia maskowania wad produkcyjnych w sygnale WA.
2
Content available Determination of the sound power level of modular machines with cyclic operation mode - case study
100%
Jakubek B. , Barczewski R.
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2020
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tom Vol. 31, nr 1
art. no. 2020101
EN
The sound power level as a parameter characterizing a sound source, as opposed to the sound pressure level, should theoretically not depend on the place of measurement and distance from the source. Therefore, it is often used as a basis for comparing machines and equipment in terms of noise emissions. Manufacturers usually specify this parameter in the technical documentation or on the equipment. The sound power level is also a necessary parameter for modelling the natural and working environment in terms of acoustics. The standards for methods of determining the sound power level define three classes of accuracy depending on the method and environment of measurement. The paper outlines the problems associated with determining the sound power level of non-standard machines in situ. The case study concerns a machine, a modular SRP (shelf ready packaging) production system that can be part of an extensive production line. Specific for this type of machine is the coexistence of many local sources generating sound of different nature, cyclic mode of operation and the possibility to set different capacity.
3
Content available Influence of mechanical and electromagnetic phenomena on electric motor vibrations in different power supply options
80%
Wróbel M. , Barczewski R. , Jakubek B. , Rukat W.
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2020
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tom Vol. 31, nr 1
art. no. 2020102
EN
Results of research about influence of mechanical and electromagnetic phenomena on electric motor vibration in different supply options has been shown in this paper. Three different supply options have been taken under consideration: typical star connection, single-phase connection with work capacitor and connection through an inverter. Vibration signals recorded on electric motor end shield and frame has been digitally processed using Multi-Synchronous Averaging (MSA). This technique allowed to decompose total vibration signal into signals associated with mechanical and electromagnetic phenomena occurring in electric motor. The comparison of rms values and spectra shapes of total and decomposed vibration signals has been made. Energy shares of previously mentioned phenomena in vibration signal for different supply options has been also estimated.
4
Content available Climatic Chamber for the Credibility Evaluation of Profilometric Measurements Construction and Control
80%
Grochalski K. , Wieczorowski M. , Pawlus P. , Jakubek B.
Advances in Science and Technology. Research Journal
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2020
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tom Vol. 14, no 3
135--140
EN
The paper shows the construction and control of a climatic chamber used for the credibility evaluation of the profilometic measurements. The paper presents a control model using a PID controller and a solution for air circulation. The data regarding the influence of environmental temperature changes on the three-dimensional representation of the surface realized by means of a tactile profilometer were presented. This work shows the temperature characteristics of a climatic chamber.
5
Content available Localization of noise sources in electric cookers based on sound pressure and intensity measurements
80%
Jakubek B. , Barczewski R. , Tabaszewski M.
Vibrations in Physical Systems
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2019
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tom Vol. 30, nr 2
art. no. 2019223
EN
The main aim of the study was to compare the features of acoustic maps created on the basis of measurements of sound pressure and intensity in a near acoustic field. Data for comparisons were obtained within the framework of acoustic tests of electric cookers. The results of these studies may help in the selection of acoustic mapping and optimization methods according to individual needs and/or requirements concerning selectivity, measurement bandwidth, dynamics and the ability to locate sound-emitting areas. The paper also presents the results of the spectral analysis of the dominant sources of noise in the cooker, which was helpful in identifying and locating paths of noise propagation from the inside of the cooker.
6
Content available A Device for Measuring the Rotational Speed of a Chain Sprocket of a Petrol Chainsaw
80%
Wróbel M. , Jakubek B. , Rukat W.
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tom Vol. 15, no 3
99--107
EN
The procedure for determining the frequency-weighted RMS values of vibration accelerations in the case of petrol chainsaws proposes equal time shares of three operation modes of the chainsaw. In order to assess the actual operator’s vibration exposure, it is necessary to precisely determine the above-mentioned shares. In real-life conditions operation of chainsaws is characterized by frequent and significant rotational speed changes depending on the operation mode. Therefore, a prototype of dedicated device for measuring the rotational speed of a chain sprocket was developed. The article presents development requirements, encountered problems and their solutions, the prototype itself and functional test results.
7
Content available Stabilization of vibro-thermal processes during post-production testing of rolling bearings
70%
Jakubek B. , Barczewski R. , Rukat W. , Różański L. , Wróbel M.
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tom Vol. 20, No. 3
53--62
EN
In the process of post-production testing of rolling bearings, quality classification and/or qualification of finished products as good and defective is performed. In view of mass production, bearing testing should be carried out within a short period of time. Vibroacoustic (VA) processes are widely used for post-production testing. Parameterization of bearing vibrations is largely determined by stabilization of lubrication conditions and VA processes, which to some extent depend on temperature. The article presents the results of temperature measurements carried out during the testing of a set of new tapered roller bearings. On their basis, an attempt was made to estimate the value of rms values of bearing vibration accelerations. This is based on the known relationships between the temperature and viscosity of the oil as well as the relationship between viscosity and acceleration of the bearing vibrations. The estimated acceleration values were verified experimentally. The time after which the temperature of a bearing is stabilized was also determined. The paper also shows the influence of a lubricant on these processes, mainly its kinematic viscosity.
PL
W procesie testowania poprodukcyjnego łożysk tocznych dokonywana jest klasyfikacja jakościowa i/lub kwalifikacja gotowych wyrobów jako dobre i wadliwe. W związku z masową produkcją, testowanie łożysk powinno się zawierać w krótkim przedziale czasu. Do testowania poprodukcyjnego powszechnie stosowane są procesy wibroakustyczne (WA). Parametryzacja drgań łożysk determinowana jest w dużej mierze przez stabilizację warunków smarowania a także procesów WA, które w pewnym stopniu zależne są od temperatury. W artykule przedstawiono wyniki pomiarów temperatury przeprowadzone podczas testowania zestawu nowych stożkowych łożysk tocznych. Na ich podstawie podjęto próbę oszacowania wartości skutecznych przyspieszeń drgań łożysk. Oparto się przy tym na znanych zależnościach pomiędzy temperaturą a lepkością oleju jak i zależnością pomiędzy lepkością a przyspieszeniami drgań łożysk. Oszacowane wartości przyspieszeń zostały zweryfikowane eksperymentalnie. Określono również czas, po którym następuje stabilizacja temperatury łożyska. Pokazano też, jaki wpływ na te procesy ma środek smarny głównie zaś jego lepkość kinematyczna.
8
Content available Temperature Measurement of Modern Cutting Tools During Turning
61%
Grochalski K. , Jabłoński P. , Talar R. , Twardowski P. , Wieczorowski M. , Jakubek B. , Rukat W.
Advances in Science and Technology. Research Journal
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2020
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tom Vol. 14, no 4
37--48
EN
The study presents the influence of the anti-wear coatings and the type of material from which the cutting tools are made of on the cutting temperature occurring on the tool. The cutting tools made of boron nitride and tungsten carbide composite were investigated. The methodology of measuring the cutting temperature using the thermoelement and thermovision techniques was presented. The results of the temperature measurements occurring on the cutting tool in the cutting zone were compared. The paper also presents a method of determining the effective emissivity of the tested tools, necessary for the correct temperature measurement using the non-contact method. The obtained data were interpreted and the relationships described, and then the results obtained were discussed.
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