An ultrasonic film thickness measuring instrument and its measuring method

Abstract

The invention provides an ultrasonic measuring instrument and a measuring method for monitoring the thickness of an oil film between two contacted surfaces. The ultrasonic measuring instrument comprises a pulse transmission circuit, an ultrasonic excitation circuit, an ultrasonic receiving circuit, a data acquisition communication circuit and a personal computer (PC) which are sequentially connected, wherein the ultrasonic excitation circuit is further connected with an ultrasonic transducer; and the pulse transmission circuit and the data acquisition communication circuit share the same single-chip microcomputer. Compared with a traditional ultrasonic thickness measuring instrument, the size of the ultrasonic thickness measuring instrument is smaller due to a digital integrated circuit, the analog-to-digital (A / D) sampling rate is very high, radio frequency sampling is directly carried out to an ultrasonic signal, and the information is not lost. A circuit design is simpler, and corresponding data can be processed. The designed instrument adopts a new oil film thickness calculation method, can measure oil film thicknesses of nano level, and is more applicable to measuring the thicknesses of lubricating oil films.

Description

technical field [0001] The invention relates to the field of ultrasonic measurement of oil film thickness, in particular to an instrument for measuring lubricating oil film thickness by using ultrasonic waves. Background technique [0002] In industrial production, in order to reduce the friction and wear when the surfaces of the workpieces in contact with each other move relative to each other, lubricants are often added between the surfaces. Among them, liquid lubrication is a commonly used lubrication method in the industry. Considering factors such as the nature and cost of the lubricant, most of the mechanical equipment such as bearings, gears, pistons and other sealing devices choose mineral oil as the lubricant. When studying liquid lubrication, it is mainly to analyze the thickness of the oil film between the friction pairs, the shape of the oil film and the pressure distribution in the oil film. The main basis for judging the lubrication state of mechanical equipme...

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Problems solved by technology

The measurable thickness range of this theoretical method is limited, and the maximum accuracy can reach 1μm. It is impossible to accurately measure the thickness of the oil film less than 1μm.

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