The design specifications that the trailer of the side lifter trailer should follow in the design process are described in detail from the selection of longitudinal beams, the calculation of longitudinal beam strength, the selection of beams, and the connection of longitudinal beams and beams.
1. The frame is the skeleton of the vehicle and an important load-bearing component of the vehicle. It is connected to the main assemblies and bears the action of the complex spatial force system. Generally, the frame should have sufficient strength, appropriate rigidity, the lightest weight under the premise of ensuring rigidity and strength, and the structure should be as simple as possible. With the development of expressways, vehicle speeds continue to increase, so the frame is required to have sufficient resistance to bending deformation and torsion deformation.
2 Precautions for designing the frame:
2.1 Almost all components of the frame are stamped parts. Therefore, the shape of each component should meet the requirements of the stamping process as much as possible. The upper torsional stress is always the largest at the flanges of the upper and lower wings, so there should be no drilling, opening or other process defects on the upper and lower wings of the frame as much as possible. Drilling is prohibited on the lower wing surface of the longitudinal beam of the frame between the front and rear axles, and the upper wing surface of the longitudinal beam of the rear suspension part. When drilling holes on the webs and crossbeams of the frame longitudinal beams, the hole spacing and hole size should comply with the regulations.
2.3 When welding parts on the frame, the material with the same welding performance as the frame material should be used for welding, and the frame cannot be welded arbitrarily.
2.4 For components that bear torsional stress, closed cross-sections such as box-shaped and round pipes with high torsional rigidity should be used as far as possible to manufacture.
2.5 In order to avoid cracks when the material is bent, the fillet radius should be larger than the thickness of the plate. For T700 steel materials, the radius of the fillet should generally be equal to 2-3 times the thickness of the plate. 2.6 If the longitudinal beam has a reinforcing plate, since the torsional stress of the longitudinal beam at the reinforcing plate decreases, but the torsional stress at the position away from the reinforcing plate increases instead, the shape of the reinforcing plate should be gradually reduced to both ends, thus Obtain a relaxed and excessive torsional stress.
2.7 The torsional stress of the longitudinal beam is divided into sections according to the beams at different positions. The torsional stress of each section and the beam is the largest or the smallest. If a beam is added between the two beams, the torsional stress of the frame The torsional stress at the place where the beam is raised and installed increases, while the torsional stress at the joint between the longitudinal beam and the original two beams decreases. This problem should be paid attention to when arranging the beam. 2.8 Where the frame needs to be strengthened, such a strengthening method can be adopted: ①The reinforcing plate with groove section is attached to the inside or outside of the longitudinal beam, and the strengthening effect is very significant; ②The reinforcing plate with L-shaped section is attached to the longitudinal beam. The side bearing the tensile stress; ③The longitudinal beam is strengthened into a box-shaped section. The method is simple and the strengthening effect is better, but it has a certain effect on its torsional stiffness; ④The wing is strengthened, but the effect is not obvious.
Post time: Aug-16-2021