Based on the parameters of a shearer and combined with the actual operation, the simulation experiment is carried out by using MATLAB system. Driving motor parameters: rated power: 1000 kW, speed: 1505 R / min; 8 sets of gear processing parameters: the number of teeth is 10, 10, 10, 12, 12, 12, 12 and 12 respectively; The dividing circle radii are 150 mm, 180 mm, 195 mm, 114 mm, 222 mm, 222 mm, 222 mm and 234 mm respectively.
Taking gear machining as an example, the effects of different tooth side clearance on gear angular acceleration under two different working conditions during start-up and normal operation are studied. Set the torque borne by the gear as 0 in the first 20 s to simulate the starting operation. The normal torque will be borne in the 20th s, about (16989.88 + 500 π T) nm. Under two different working conditions, gear machining is simulated and compared with no clearance and 0.5 mm clearance respectively. The results are shown in Figure 1.
It can be seen from Figure 1 that in the start-up stage and normal operation stage, the angular acceleration of the gear shows a nonlinear change trend with time. When there is no tooth side clearance and there is 0.5 mm tooth side clearance, the maximum angular acceleration of the gear is 4.096 respectively × 103 rad / S2 and 2.211 × 104 rad/s2。 It can be seen that the increase of tooth side clearance obviously increases the torsional vibration degree of the gear and has a great impact on the transmission accuracy of gear machining.
According to the above analysis method, different tooth side clearances are simulated respectively. The results show that in the start-up stage and normal operation stage, the angular acceleration of the gear with tooth side clearance is greater than that without tooth side clearance. In order to analyze the influence of different tooth side clearance on the angular acceleration of each gear, the maximum angular acceleration of different gears with and without tooth side clearance is extracted for comparison. When there is 0.1 mm and 0.5 mm clearance in gear machining, the maximum angular acceleration comparison curve is shown in Figure 2.
Through the analysis of Figure 2, it can be seen that the change trend of gear angular acceleration without backlash is basically the same in the start-up stage and normal operation stage. With the change of tooth side clearance, the maximum angular acceleration value of the gear also changes accordingly. Under the same tooth side clearance, the maximum angular acceleration of the first four groups of gears is greater than that of the last four groups of gears. When the clearance is 0.1 mm, the angular acceleration value of gear 4 is the largest, which is 1.282 84 × 104 rad/s2； At a clearance of 0.5 mm, the angular acceleration value of gear 2 is the maximum, which is 2.241 34 × 104 rad/s2。 The reason is that the number of teeth processed by the first four groups of gears is relatively small, the radius of the dividing circle is small, and the idle angle in the rotation process is larger than that of the last four groups of gears, so the impact force is large, resulting in a large value of gear angular acceleration, which is more consistent with the actual situation.