Through the free mode calculation results, it can be seen that the first six modes of the gearbox shell are rigid modes, which are represented by the displacement of the rigid body along the XYZ axis and rotation Through the free mode calculation results, it can be seen that the first six modes of the tractor gearbox shell casting are rigid modes, which show that the rigid body displaces along and rotates around the XYZ axis, and its natural frequency is close to zero; After the 7th order is the elastic mode. The vibration modes and frequencies of the 7th to 12th order modes of the tractor gearbox shell casting are shown in the figure, and the natural frequencies and vibration modes of the 7th to 15th order free modes are described in the table.
8th Order (431.25hz) overall tension bending vibration
10th order (782.22hz) front end shrinkage and torsion deformation
12th order (884.69hz) overall torsional vibration
It can be seen from the table that the seventh order elastic free modal frequency is 288.04hz, and its vibration mode is the overall bending vibration of the tractor gearbox shell casting. The subsequent elastic free modal frequencies increase in turn, which corresponds to the vibration mode.
| Drgree | Frequency (Hz) | Vibration mode |
| 7 | 288.04 | Overall bending vibration |
| 8 | 431.25 | Integral tension bending vibration |
| 9 | 501.01 | Diagonal tension contraction torsion transition |
| 10 | 782.22 | Front end shrinkage and torsion deformation |
| 11 | 867.90 | Overall bending vibration |
| 12 | 884.69 | Overall torsional vibration |