ANALYSIS OF VIBRATION CHARACTERISTICS AND STRUCTURAL OPTIMIZATION OF THE CHASSIS FRAME OF CRAWLER-TYPE COMBINE HARVESTER

To investigate the vibration characteristics of the Thinker Agricultural Machinery 4LZ-2.0 crawler-type combine harvester under operational conditions, vibration tests were conducted on the chassis frame at three different engine speeds: 2700 r/min, 1500 r/min, and 800 r/min. A static analysis was initially performed to identify regions of significant stress and deformation on the chassis frame, which guided the placement of measurement points for collecting vibration acceleration data. Subsequent processing of the acceleration data in the frequency domain revealed the variation in vibration velocity at each measurement point on the chassis frame. It was found that as the engine speed increased, the excitation frequencies from the vibrating screen and cutting platform appeared as dominant resonance frequencies at nine out of twelve measurement points on the chassis frame. By referencing the international standard ISO 20816, it was determined that most of these measurement points fell into Class D, indicating a high level of vibration severity. To mitigate the vibration of the chassis frame, two measures were implemented: enhancing the structural rigidity of the frame and reducing the area of the center of mass trajectory of the vibrating screen. Following these modifications, re-testing showed that the average vibration intensity at the three maximum vibration measurement points of the chassis in the high engine speed condition successfully decreased by 34.57% compared to the original structure.