DD284388A7 - TASTSONDE FOR AMBULANT VIBRATION MEASUREMENTS - Google Patents

Abstract

The invention serves to support the ambulatory vibration monitoring of rotor-bearing systems, in particular for mass diagnosis of rolling bearings according to the * Erfindungsgemaesz the probe uses a sound conductor, preferably made of ceramic material, which is designed as a cylindrical rod with hemispherical Abschlusz and whose length is 1 to 2 times its diameter does not exceed. Due to the structural design of the arrangement, the vibration transmission characteristic already meets the mesztechnischen requirements for the rolling bearing diagnosis after the * {sound conductor; Vibration measurement; Bearings; piezoelectric accelerometer}

Description

an electrically insulating layer, for. For example, epoxy resin, achieved. It is also essential to the invention that the touch probe is designed to eliminate the need for a long signal transmission path while taking into account a minimum signal attenuation in the frequency range of 1-10 kHz which is relevant to the rolling bearing. Due to the structural design of the sound conductor, the vibration transmission characteristic of the probe already sufficient with low contact forces the metrological requirements of the rolling bearing diagnostics after the K (t) method.

Fig. 1 shows the dependence of the signal power recorded rolling bearing vibrations of the contact pressure of the arrangements used for coupling the piezoelectric accelerometer to the bearing. With the touch probe 1.1 according to the invention, the signal power is greater in comparison to the industrial stylus tip 1.2 and almost independent of the contact pressure F (N). For these reasons, the length of the sound conductor should not exceed 1 to 2 times its diameter and correspond to the rest of the housing front part on the Meßstellenoberfläche displaceable path of the sound conductor ¹ A to Ѵг its length.

With this arrangement, multiple advantageous effects over other sound transmission arrangements are achieved

- Ensuring routine ambulatory serial measurements for the diagnosis of rotor-bearing systems, in particular for mass diagnosis of rolling bearings according to the K (t) method with high reproducibility of the measured values without measuring point preparation and with minimal time required for the measured value recording

- Ease of use of the probe due to low contact force with significant improvement in the vibration transmission characteristic

- Structural simplicity of the probe using industrially manufactured parts

- Practical design with great durability.

The high technical effectiveness of the invention, combined with a practical user-friendly design creates an essential prerequisite for the mass diagnosis of rolling bearings under industrial conditions.

embodiment

The touch probe according to the invention is explained below using an exemplary embodiment:

Fig. 2 shows a section through the probe. An industrially manufactured piezoelectric acceleration sensor 2.1 is screwed to a sound conductor 2.2 designed as a cylindrical rod with a hemispherical termination. A plastic sleeve 2.3 surrounds the piezoelectric accelerometer 2.1 and serves to guide and vibration damping of the pickup system in the front housing part 2.4. The housing rear part 2.5 is screwed to the housing front part 2.4, supports a prestressed compression spring 2.6 and contains the implementation of the measuring cable 2.7. Compression spring and length of the housing rear part are dimensioned so that the required contact pressure of the sound conductor is applied against the measuring point in the assembled and ready state of the probe and the reproducibility of the measured values is guaranteed. For data acquisition, the probe with the hemispherical termination of the sound conductor is set perpendicular to the measuring point and the housing of the probe against the spring force of the compression spring in the direction of the measuring point so far moved until the housing front part of the probe rests against the Meßstellenoberfläche.

Claims (2)

Tactile probe for ambulatory vibration measurements on rotor bearing systems for mass diagnosis νοη rolling bearings according to the K (t) method with a cylindrical sound conductor with hemispherical termination, which is bolted to an accelerometer, these are movably mounted in a front housing part and between a piezoelectric accelerometer and a plastic sleeve is arranged known per se, characterized in that the length of the Schalletters (2.3) is 1-2 times its diameter, the displaceable path of the sound conductor (2.2) УL to V2 corresponds to its length and the housing front part (2.4) during the measuring process rests on the measuring point surface. For this 2 pages drawings Field of application of the invention The invention relates to an arrangement for ambulatory vibration measurements on rotor-bearing systems, in particular for mass diagnostics of rolling bearings according to the K (t) method. Characteristic of the known state of the art For the rolling bearing diagnostics according to the K (t) method, the structure-borne noise must be measured on the bearing housing. A piezoelectric accelerometer is used, which is coupled to the bearing housing for ambulatory measurements by means of a screw, probe or magnetic connection or quick coupling for the duration of the measurement. Screw connections have the best vibration transmission behavior compared to other types of connection. Decisive disadvantage, however, is the effort required to prepare the measuring point, for fixing the piezoelectric accelerometer and for protecting the threaded piece against corrosion and contamination. A so-called quick-release coupling (application note from VEB ROBOTRON Messelektronik "Otto Schön", Dresden, 1987) combines good vibration transmission characteristics with minimal effort for coupling the accelerometer The quality of the surface grinding reduces over time due to corrosion and contamination, so that the vibration transmission properties are uncontrollably worse and eliminates this type of coupling for cyclic measurements in the context of the rolling bearing diagnosis Inadequate vibration transmission behavior in the required frequency range of 1-1OkHz can not be used Signal transmission behavior for frequencies up to 10 kHz (DD-PS No. 219570) uses compressed air for the non-positive connection of the probe tip to the DUT and is designed for automatic measurements. Another scanning device (DE-PS No. 3439546) wideband amplifies the structure-borne noise signal by means of Helmholtz resonator to allow suitable conditions for a leak detection. A device for recording structure-borne sound vibrations (AT-PS No. 379898) has a housing displaceable and biased by spring force receiving arbor, which is placed on the measurement object for measurement. With the proposed arrangement, a defined contact pressure of the receiving mandible on the test object can not be realized or only with particular care. But the measurement conditions are not reproducible in every case. Other arrangements differ essentially only by design details, such as arrangement and construction of the piezoelectric crystal, installation of electrical insulation layers, etc. (SU-PS No. 1270680). For routine ambulatory vibration measurements for rolling bearing diagnostics according to the K (t) method, the known arrangements for structure-borne sound transmission from the test object to the piezoelectric accelerometer with respect to transmission characteristics, technical complexity and operability are not designed according to requirements. Object of the invention The aim of the invention is to minimize the expenses for the Meßstellenvorbereitung and measured value recording for routine routine vibration measurements for the diagnosis of rotor-bearing systems, in particular for mass diagnosis of rolling bearings according to the K (t) method while maintaining the metrological requirements. Explanation of the essence of the invention The invention has for its object to present an arrangement that makes it possible without Meßstellenvorbereitung a piezoelectric accelerometer for the period of Meßwertaufnahme for the purpose of diagnosis of rotor-bearing systems, in particular for mass diagnosis of rolling bearings according to the K (t) method the measuring point frictionally coupled. According to the invention, the arrangement uses an electrically insulated sound conductor of very hard material in the execution of a cylindrical bar with hemispherical termination. The rod is screwed to a known piezoelectric accelerometer, guided in a special housing and biased by a compression spring. An electrical insulation of the sound conductor is made by using ceramic materials or by introducing