An improved ultrasonic method for lubricant-film thickness measurement in cylindrical roller bearings under light radial load

Li, Meng; Jing, Minqing; Chen, Zengfan; Liu, Heng

doi:10.1016/j.triboint.2014.04.023

Cited by 25 publications

(14 citation statements)

References 16 publications

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“…The results prove that there was a greater spatial resolution for the ball profile by using high PRR but only one ball could be imaged. This advantage was also proven by Li et al [16] in 2014 for the oil-film measurement in a cylindrical roller bearing.…”

Section: Introductionmentioning

confidence: 62%

Ultrasonic Measurement of Cylindrical Roller Bearing Lubrication Using High Pulse Repletion Rates

Liu

et al. 2015

Journal of Tribology

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This paper describes a measurement of lubricant-film thickness in a roller bearing using a new ultrasonic pulser-receiver, which has a maximum pulse repetition rate (PRR) of 100 kHz. The experimental results show that a higher PRR can help to get more measurement points and more details of the oil-film thickness distribution. Furthermore, the influence of rotor vibration response for the oil-film thickness is discussed, which is in keeping with the simulation result. Finally, the limits of the PRR are discussed in detail and the effect of the transducer focal zone size is also observed. IntroductionThe lubricant layer is a separation between the races and the elements in a roller bearing, which reduces friction and wear and provides smooth operation and long life for machines. Therefore, the thickness and behavior of the lubricant film are important to model and measure. However, it is very difficult to measure this lubricant-film thickness directly in industrial applications as the load is carried by an extremely thin lubricant film over a very small lubricated region.Electrical and optical methods have been used to measure the lubricant-film thickness. Resistance and capacitance methods are sensitive to the surface roughness and require electrical isolation [1][2][3]. Optical methods need translucent materials so they are rarely used outside the laboratory [4,5]. Compared with the methods mentioned above, the ultrasound method [6-8] removes the requirement of electrical isolation and transparency. The reflection coefficient of longitudinal ultrasonic waves has been shown to be highly sensitive to the lubricant-film thickness [9]. This method has been applied to a range of bearings including journal and ball bearings [10][11][12].

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Section: Introductionmentioning

confidence: 62%

Ultrasonic Measurement of Cylindrical Roller Bearing Lubrication Using High Pulse Repletion Rates

Liu

et al. 2015

Journal of Tribology

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“…Measurements of lubricant film thickness in rolling element bearings under elastohydrodynamic lubrication through ultrasonic reflectometry have been successfully conducted previously [24][25][26][27][28][29]. As a result of the small contact area of the raceway and rolling element, focusing of the ultrasonic waves is required to ensure that the ultrasonic beam falls within the contact dimensions.…”

Section: Measurement Methodologymentioning

confidence: 99%

“…This means that to measure the oil film that forms in a small-sized EHL contact, focusing of the beam is necessary. This has been conducted successfully in laboratory studies [25][26][27][28][29], but the need for a liquid-coupled focusing bath renders the approach unsuitable for field applications. Since the purpose of this work is to study bearings under field conditions, simpler bonded-on sensors were used.…”

Section: Introductionmentioning

confidence: 99%

Detection of Lubrication State in a Field Operational Wind Turbine Gearbox Bearing Using Ultrasonic Reflectometry

2021

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Fully flooded lubrication is the ideal state for a rolling bearing; this is especially true in the aggressive environment of a wind turbine transmission where bearings are subject to intermittent operation and highly variable loading. In this paper, a novel ultrasonic reflection method is used to detect the presence of oil between rollers in the bearing. Ultrasonic sensors were instrumented on the static inner (lab) and outer (field) bearing raceways and reflections were captured as the rollers travelled past the sensor. The proportion of the sound wave reflected (known as the reflection coefficient, R) is dependent on the acoustic mismatch of the materials either side of the interface. Changes in R indicate either a steel–air or steel–oil interface as R values transitioned from 1 to 0.95, respectively, and even lower for a steel–roller interface. Consequently, it was possible to detect the presence of lubricant on the raceway between roller passes. From the laboratory measurements, the recurring reflection coefficient patterns between roller passes were used to identify the lubrication condition of the raceway. An absence of these patterns between roller passes indicated the absence of lubricant on the bearing surface. For the field measurements, three bearing lubrication conditions (partial, insufficient, and fully lubricated) were observed. Partially and insufficiently lubricated datasets were found to occur mostly during transient operation. As transient operation is often accompanied by overloading and torque reversals, coupled with the lubrication issues, these all act to increase the risk of premature bearing failure.

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“…The most commonly used techniques are vibration measurement, acoustic emission (AE) analysis, electrostatic (ES) measurement [6,7], bearing temperature analysis [8], ultrasonic measurement [9], Shock Pulse Method (SPM) [10], wear debris analysis [11], and modal analysis [12]. Despite the fact that there are many techniques to monitor the conditions of rolling-element bearings, the vibration analysis is one of the basic methods to control technical conditions of new bearings.…”

Section: Rolling Bearings Diagnostic Methodsmentioning

confidence: 99%

Influence of raceway waviness on the level of vibration in rolling-element bearings

Adamczak

Zmarzły

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. This paper provides a quantitative analysis of how raceway waviness (RONt) in 6304-type bearings affects their vibration. The waviness of bearing races was measured at the actual points of contact between the balls and the races. The measurements were conducted in the range of 16-50 undulations per revolution (UPR). The bearing vibration was analyzed in three bandwidths of frequency: low (LB) (50 ÷ 300 Hz), medium MB (300 ÷ 1800 Hz) and high HB (1800 ÷ 10 000 Hz), as well as in the full RMS bandwidth. The paper also presents the procedure used to determine the actual points of contact between the ball and each race to specify the point of waviness measurement. The method of calculation of the contact angle for a ball bearing is also discussed. The Pearson linear correlation coefficients were determined to analyze the relationships between the waviness parameters and the level of vibration. The test results show that an increase in the surface waviness on the inner and outer raceways causes an increase in the vibration level. The influence is most visible for the medium frequency bandwidth.

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An improved ultrasonic method for lubricant-film thickness measurement in cylindrical roller bearings under light radial load

Cited by 25 publications

References 16 publications

Ultrasonic Measurement of Cylindrical Roller Bearing Lubrication Using High Pulse Repletion Rates

Ultrasonic Measurement of Cylindrical Roller Bearing Lubrication Using High Pulse Repletion Rates

Detection of Lubrication State in a Field Operational Wind Turbine Gearbox Bearing Using Ultrasonic Reflectometry

Influence of raceway waviness on the level of vibration in rolling-element bearings

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