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

Abstract

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].

Study on the rotational speed of bearing cage based on ultrasonic measurement

“…In this paper, a new method for ultrasonic measurement of bearing cage speed based on the theory of ultrasonic reflection 14,15 in roller bearing is proposed, which does not require any treatment of cage, and is not sensitive to the environmental factors such as oil mist. Comparing the experimental results with the traditional optical method measurement result and the theoretical calculation result, the feasibility of this method for condition monitoring of roller tilt in industrial applications is analyzed.…”

Review of ultrasonic-based technology for oil film thickness measurement in lubrication

“…A new type of ultrasonic pulser-receiver with a maximum pulse repetition rate of 100 kHz has been developed, and the speed of bearing that can be measured has been increased to 2000 rpm and the measurable working range has been greatly expanded [66]. The simulation analysis shows that the roller vibration is the cause of the fluctuation of lubrication film thickness.…”

An improved method for film thickness measurement of cylindrical roller bearings based on a straight-beam probe

“…Cylindrical roller bearings are widely used in all kinds of rotating machinery systems as industrial joints (Song et al , 2018), and their running performance and stability are closely related to the lubrication state between roller and inner and outer rings. The thickness distribution of lubrication film in the contact area of cylindrical roller bearings can directly reflect the lubrication contact state of bearings (Li et al , 2015) . But it is difficult to measure under working conditions.…”