Dynamic Detection Of Axial Force And Radial Force Based On Cylindrical Sensor

Water pump is one of the most common mechanical devices.In practical engineering applications,the performance of the pump shaft is the key factor affecting the smooth operation of the pump.The water pump inside is the fluid mechanical structure.In its operation process,the impeller before and after the fluid pressure difference will produce axial thrust on the pump shaft,when the axial thrust is too large,beyond the pump to withstand the range,will affect the pump life.In addition,the centrifugal force generated by the installation deviation of the blade and pump shaft and the geometric center and the gravity center do not coincide.This centrifugal force constitutes the radial force of the pump rotor.When the radial force exceeds the range of the pump bearing,it will lead to impeller wear chamber,bearing wear and other issues.The common measurement method of axial force and radial force is stator-mounted sensors the of the water pump.The cylindrical load cell is mounted on the rotor of the pump(pump shaft),reducing the loss of force from the rotor to the stator,the result more acurrate.By looking at the corresponding literature found that predecessors have not used a similar measurement method,because there is no reference example,a lot of technical and detail issues need to be overcome.During the measurement,the cylindrical force sensor is rotated at high speed with the pump rotor.In order to prevent the wire winding,the data acquisition board,lithium battery and waterproof seal are installation into the cylindrical elastic element.The mechanical structure of the water pump is compact and the internal space is small,which limits the mechanical dimensions of the cylindrical force sensor,so the data acquisition board device has high density and difficult to route.This paper analyzes the causes of the axial force and radial force of the water pump,analyzes and explains the working principle of the cylindrical force sensor and the design of the data acquisition board.The process of the actual test of the water pump is detailed elaboration.The static parameters of cylindrical force sensor such as the range,linearity,and sensitivity of the axial force and the range,linearity and sensitivity of the radial force are demarcate by the tension machine.Through the motor drag the cylindrical force sensor rotation way,get the sensor to simulate the actual operation test data.Fourier transform is used to obtain the signal amplitude-frequency characteristic curve,and the frequency characteristics of the acquired data are analyzed.In order to eliminate the vibration caused by the motor rotation and the multiple harmonics ingredients,to get effective data are obtained.Use the method of mean filtering to extract the valid data.Compared the effective data obtained by the test with the static calibration data,obtain that the full scale error between the simulated actual running result of the water pump and the static calibration result at the state of the same load.