In the second-order mode, the upper beam of the fuselage is twisted back and forth by the vertical center line passing through the bearing hole. This vibration mode increases the stress at the joint between the column and the table, which is easy to cause fatigue damage, and the upper and lower slewing heads are misaligned before and after. The torsional vibration mode makes the gap between the slider and the guide rail uneven, which increases the wear of the slider, reduces the guiding precision, and affects the life of the device. In the fourth-order mode, the beam on the fuselage vibrates left and right while the right wing vibrates back and forth. This mode shape causes the up and down slewing heads to be misaligned in the left and right direction, and the upper and lower dies cannot be aligned, and the influence is similar to the first order mode. The left and right vibration of the fuselage affects the feed accuracy of the table transmission mechanism, thereby reducing the positioning accuracy of the blank. In the eighth-order mode, the upper beam of the fuselage is bent up and down. The vibration mode changes the distance between the upper beam and the table, the bottom dead center of the slider is not fixed, and the vibration of the upper beam forms an angle between the upper and lower slewing heads, which reduces the angular rigidity of the fuselage and affects the forming. Precision. In addition, since the deformation force acts vertically on the body and is the same as the vibration direction of the body, it is easy to cause resonance. In the third-order mode, the whole body is basically not moving, and the four corners on both sides of the fuselage, especially the front and rear plates of the lower right corner, vibrate. This mode is a local mode and does not have much effect on the machining, but it increases the noise. The large number of local modes indicates that there is a weak local stiffness. After analysis, it is found that the sides of the fuselage are open plate structures, and there is no rib connection between the front and rear plates, and the rigidity in the vertical direction of the plate is very weak, which is easy to cause vibration. This vibration reduces the natural frequency of the device, so the designer should enhance the local stiffness. The dynamic structure optimization is known from the modal analysis results. In many local vibration modes, this indicates that the local stiffness is weak. The reason for the analysis is that the periphery of the fuselage is an open structure, and the front and rear panels are in a cantilever state, which easily causes vibration of the front and rear panels and reduces the natural frequency of the system. In addition, it can be seen from the first-order vibration mode that the deformation of the left and right vertical columns of the fuselage is uneven, indicating that there is a problem that the rigidity of the left column is strong and the rigidity of the right column is weak, which also causes the system modal frequency to be low. In order to solve the above problems, the fuselage structure was improved, and the upper cross member intermediate plate was extended to the right to the edge of the fuselage; the front and rear additional plates were removed, and the throat vertical plate thickness was changed to 40 mm; the left and right sides of the fuselage and the upper outer edge A steel plate with a thickness of 10 mm is welded to form a closed structure. The morphological calculation is performed on the improved structure using the Lanczos method, which is compared with the calculation result of the natural frequency of the original structure. The first four-order mode of the new structure has become the left and right overall vibration, which has little effect on the machining accuracy. The finite element model of the numerical control rotary head press body was established. The theoretical modal calculation was carried out by using the structural analysis software MARC. The first ten modes of the structure were obtained. The influence of each mode shape is analyzed and compared. It is found that the first-order mode has a front-back vibration in the upper right corner, indicating that the stiffness in the upper right corner is poor. (Finish) Waterproof Linear Actuator,Power Recliner Actuator,Recliner Chair Linear Actuator,Linear Actuator For Recliner ZHEJIANG XINYI INTELLIGENT DRIVE TECHNOLOGY CO.,LTD , https://www.xinyiactuators.com
Research on Dynamic Structure Optimization of CNC Press