The specific implementation process of vibration experiment is as follows:
(1) Make preparations before the formal experiment. First, check that the wiring is connected correctly. Then, clean and lubricate the device surface of power transmission part (mainly refers to two gears) and load part (i.e. magnetic powder brake) in the experimental platform to ensure smooth surface of gear pair and magnetic powder brake, and remove the influence of irrelevant factors during gear system operation.
(2) The experimental platform is placed on a flat and smooth platform which can make the spur gear and the non-circular gear mesh correctly. Before the formal test, let the whole experimental device idle at a suitable speed for a period of time, so as to ensure that the experimental device is in the best working state. Then, three experiments in step (3) are carried out.
(3) The specific implementation process of the three experiments
The characteristics of gear vibration are determined by the internal excitation in gear meshing. The vibration is transmitted through the gear and the supporting structure, including the torsional vibration of the gear and the linear vibration of the support. Although the amplitude of the torsional vibration and the linear vibration are different, their frequency and amplitude change with the parameters are the same. Therefore, in this experiment, the linear acceleration sensor is used to test the gear supporting structure In order to verify the variation law of torsional vibration frequency and amplitude with parameters in theoretical analysis.
Experiment 1: the input speed is set at 560r / min and the load torque is 10 N · M. the vibration acceleration signal of gear system is tested. The amplitude frequency curve of vibration signal is obtained through fast Fourier transform, and the main frequency components are analyzed, and the harmonic frequency components of vibration response in the theoretical results are verified.
Experiment 2: set the input speed unchanged, change the load torque, and test the variation of PPV with load torque.
When the input speed is maintained at 560r / min, the tension controller knob which controls the torque of magnetic powder brake is adjusted. When the load torques are 7.5n · m, 5N · m, 2.5n · m and 0n · m, the vibration acceleration time domain response of the reducer variable speed integrated gear transmission system is extracted, and the peak to peak value of dynamic response under different load torque is extracted. Considering the influence of random factors and test errors in the test, the average value of peak to peak value in multiple vibration periods is taken as the final peak to peak value, and then the variation law of vibration acceleration peak to peak value with load torque is analyzed. Because the backlash of the reducer variable speed integrated gear is real under the actual working state, the response peak to peak value PPV versus load torque curve b) is compared and analyzed when considering the nonlinear dynamic model of backlash in this paper, so as to verify the correctness of the change trend of response peak to peak value PPV with load torque obtained from theoretical analysis.
Experiment 3: set the load torque unchanged, change the input speed, and test the variation of PPV with input speed.
Adjust the tension controller knob to control the torque of magnetic powder brake to keep the load torque of gear system at 5N · M. According to the rated speed of the three-phase variable frequency adjustable speed motor, the actual speed of the three-phase variable-frequency motor is adjusted by the frequency converter. After the two gears operate stably, the test speed is 1120r / min, 840r / min, 560r / min and 280r / min respectively In order to verify the response peak to peak value (PPV) obtained by theoretical analysis, the peak to peak value of vibration acceleration is also extracted under different experimental conditions, and the variation law of vibration acceleration peak to peak value with input speed obtained from theoretical analysis is compared with the curve b) of response peak to peak value PPV obtained by theoretical analysis The correctness of the change trend with the input speed.