This section provides overview, applications, and principles of vibration sensors. Also, please take a look at the list of 24 vibration sensor manufacturers and their company rankings.
Vibration sensors are sensing elements used to measure the vibration state of machines and objects.
Vibration sensors are essential for understanding and monitoring the vibration state of machinery. The vibration of an object can be expressed in terms of acceleration, velocity, and displacement. Vibration sensors measure these physical quantities and convert them into electrical quantities such as voltage and current.
Generally, vibration sensors are composed of two types of sensors, contact and non-contact. These two types of vibration sensors must be used according to the physical quantity to be measured (acceleration, velocity, displacement) and the situation of the object. For a detailed selection of a vibration sensor to further improve measurement accuracy, it is necessary to consider the magnitude and frequency range of the vibration of the object and the measurement environment.
Vibration sensors are used in production equipment and research and development. In production facilities, vibration sensors are used for preventive maintenance to detect equipment failures and damage at an early stage. The use of sensors can prevent the occurrence of huge repair costs and reduce production efficiency caused by breakdowns and damage. In recent years, small vibration sensors have been used in production facilities, mostly for the purpose of machine diagnosis and predictive maintenance using IoT technology.
Examples in the field of research and development include the use of vibration sensors for vibration and shock measurement, which are used for product testing and durability testing. In recent years, vibration sensors have also been used to evaluate passenger comfort, particularly in the automotive industry. In other industrial fields, vibration sensors are used for a wide range of applications, including electrical equipment, automobiles, and production robots.
As mentioned above, there are two types of vibration sensor configurations: contact and non-contact. Contact vibration sensors are used to measure acceleration, while non-contact vibration sensors are used to measure velocity and displacement. Here we will introduce the principle of each vibration sensor suitable for various vibration (acceleration, velocity, and displacement) measurements.
This sensor uses the piezoelectric effect. In piezoelectric materials (piezoelectric elements) such as single quartz crystals, when subjected to a force, an electric charge is generated on its surface, and using this principle, an electrical signal corresponding to the acceleration is output.
This is a sensor that uses the Doppler effect. A laser Doppler sensor detects velocity by irradiating a laser beam from the sensor onto a vibrating object and converting the frequency change of the laser beam reflected from the vibrating object, i.e., the velocity change, into a voltage.
Capacitive sensors are sensors based on the principle of measuring the capacitance between the sensor and the object to be measured and calculating the distance. When the distance between the sensor and the object to be measured changes, the capacitance value changes, and the displacement of the object is measured for the amount of change in this capacitance value.
According to JIS, the detection element of mechanical vibration is the change in the magnitude of a quantity representing the motion or displacement of a mechanical system over time. In many cases, the vibration alternates between a state greater than and less than the average or reference value, and in general, this vibration is composed of three elements: amplitude, frequency, and phase.
In particular, a vibration that repeats at regular intervals is called harmonic vibration and consists of a single frequency. In such cases, displacement, velocity, and acceleration are as follows. By differentiating the displacement, the velocity can be derived, and by differentiating the velocity, the acceleration can be derived.
Where D: single amplitude, ω: each velocity ω=2πf, f: frequency f=1/T, T: period (sec), Φ: initial phase.
Types of vibration sensors used to detect this harmonic vibration include acceleration sensors (piezoelectric type), velocity sensors (electrokinetic type), and non-contact displacement sensors (eddy current type). Among these, piezoelectric acceleration sensors in particular, are widely used because of their ability to cover a wide frequency range.
As an example, the use of piezoelectric vibration sensors for vibration monitoring is described below. Piezoelectric vibration sensors use the piezoelectric effect to generate and output an electric charge proportional to the external force applied. Piezoelectric vibration sensors with charge output are particularly advantageous in terms of miniaturization. This is a situation where they are used universally in a wide range of applications.
The sensor should be firmly fixed with stud bolts or other means so that it adheres closely to the non-measured object. If the sensor is not firmly attached, it may show filter characteristics with peculiar attenuation characteristics in the frequency response, etc., making accurate measurement impossible. Note that other methods of securing the sensor include the use of adhesives or magnets.
Frequency analysis is widely used to analyze data detected from vibration sensors. Frequency analysis is a method of examining the frequency components and intensity of the measured waveform. The analysis provides an indicator that can be used to determine if the vibration of an object is under normal operating conditions.
*Including some distributors, etc.
Sort by Features
Sort by Area
This is the version of our website addressed to speakers of English in the United States. If you are a resident of another country, please select the appropriate version of Metoree for your country in the drop-down menu.