Bearing Vibration Measuring Instrument-Development Of Data Acquisition System

Rolling bearing is widely used in machinery manufacturing scroll parts, especially in the rotating machinery. The role of the rolling bearing is to share the load and transfer the load, so quality and operation condition is directly related to the whole device’s working condition. According from the past data statistics, if the equipment concludes the bearing part, about35%of all mechanical breakdowns are related to the bearing. So researching on the bearing tests can reduce the probability of major accident risk as much as possible which is also significant for accelerating the development of mechanical industry as well as changing on the maintenance system.At present there are two main types of bearing vibration tester. One is composed of discrete components. The other one is a set of instruments which use the PC control combined with the data acquisition card and the Labview shows. Their shortcomings are obvious that is the data processing ability of them is limited and the Labview software is expensive. As the cost of using it is high, it’s not suitable for a wide rage of application.The main research content of the thesis includes:(1) the hardware design of the controller. Controller chooses STM32F103VET6as main control chip, the chip internal integrates FLASH, RAM, TIMER, USART, etc which can realize the digital quantity input/output and achieve the purpose of control.(2) the signal acquisition and filtering. It uses the sensors to acquire the vibration signal and gets the digital filter by using A/D conversion. The filter can be divided into three frequency bands. The50-300Hz low frequency band is the clamping deformation of bearing inner ring and outer ring which is basically due to the large messing force of the multiple claw chunk. The middle-frequency band300-1800Hz is the rippling which is caused by the vibration of the grinder and the unbalance of the grinding wheel, leading to the motor vibration of the grinding wheel in the process of grinding between the steel ball and the inner and outer ring raceway. The high frequency band1800-10k Hz is the vibration which is basically caused by the roughness degree of the steel ball and the surface of the trap race.(3) the peripheral control module. In order to control the load force of the cylinder on the bearing which is to be measured, it is used the serial port to control the transducer on rotate speed adjustment and the digital quantity to control the external electromagnetic relay.(4) results display. It is used the LCD to show the frequency value of the three frequency bands by filtering which are able to express more intuitive.