When designing a trailer, considering the compatibility with the tractor is a complex and important link, involving multiple considerations. The following are several key points to consider when designing a trailer to match the tractor:
1.Height matching of the towing seat:
- The saddle height of the tractor and the towing plate height of the semi-trailer are matched with each other. When designing, engineers usually set the height of the semi-trailer towing pin slightly lower than the saddle of the tractor by 30-50mm to ensure that after the connection, the semi-trailer can rely on gravity to press on the saddle of the tractor.
2.Front overhang of the tractor and the front turning radius of the semi-trailer:
- The front turning radius of the tractor and the front turning radius of the semi-trailer are two different data. When designing, it is necessary to avoid interference when turning after connection.
- The national standard stipulates that the front turning radius of the semi-trailer should not exceed 2040mm to ensure that the vehicle length meets the national standard limit requirements.
3.Interchangeability dimensions and control dimensions:
- National standard GB/T 20070.2 specifies the interchangeability dimensions, control dimensions and markings of mechanical connections between low-traction semitrailer tractors and large-volume semitrailers.
- Under the maximum load state, the ground clearance of the traction joint surface of the semitrailer tractor should be 900mm~950mm.
4.Longitudinal and side tilt angles:
- When the front and rear tilt angles of the semitrailer relative to the semitrailer tractor meet certain requirements, it should not contact the semitrailer tractor (except for articulated parts). Forward tilt angle ω1≤3.5°; rear tilt angle ω2≤4.5°.
- When the side tilt angle is not greater than 2°, there should be no interference between the semitrailer tractor chassis and the semitrailer.
5.Articulation angle:
- In the state of car train, the articulation angle φ of the semitrailer tractor and the semitrailer should be able to reach 90°, and when the articulation angle increases from 25° to 90°, and the rear caster angle decreases from 4.5° to 3°, there should be no interference between the tires or fenders of the semitrailer and the semitrailer tractor.
6.Free space between the semitrailer tractor and the semitrailer:
- Certain regulations should be met to ensure that the distance L4 between the two rotating cylinders is greater than or equal to 100mm, and the horizontal distance L5 between the rotating cylinder and the cone surface is greater than or equal to 80mm.
7.Gooseneck dimensions:
- The semitrailer gooseneck shape should have a reasonable size to avoid the movement interference between the tractor rear suspension upper longitudinal beam and the semitrailer gooseneck due to too small size.
Through these detailed design parameters and standards, a good match between the trailer and the tractor can be ensured, thereby improving transportation efficiency and safety.
