Zonxin Semi-trailer Air Suspension User Manual

Ⅱ. Installation and Adjustment of Air Suspension

This chapter explains the installation and welding of the front-mounted German-style 13T air suspension with a 150 square axle. The installation and welding methods for other models are basically the same.

The temperature of the welded parts should be ≥10°C. It is recommended to preheat the connection area of the welded parts (the welding length plus 15 mm on each side) to 200°C before welding.

2.1 Positioning and Welding of Welded Parts

2.1.1 Positioning and Welding of Air Suspension System and Frame

Invert the frame. According to the design dimensions of the trailer manufacturer’s vehicle, mark the axle centerline on the lower flange of the frame. Using the axle centerline as the reference, mark the centerlines or contours of the guide leaf spring bracket and the upper support bracket of the load-bearing airbag, ensuring that the diagonal dimensions are equal.

2.1.1.1 Welding Position of Guide Leaf Spring Bracket

(1) Using the centerline of the first axle as the reference, fix the longitudinal position of the leaf spring bracket toward the vehicle’s forward direction with a dimension of P1±1mm, and the lateral fixed position with a dimension of L1±1mm (refer to the design plan for P1 and L1 values).

Note: The weld height between the leaf spring bracket, air spring upper bracket, and the chassis frame should be 8–10 mm.

(2) After confirming the position of the left and right guide leaf spring brackets, measure the diagonal dimension M of the brackets, ensuring it is within M±1mm.

(3) Simultaneously, using the center of the fixed kingpin (point A) as the reference, adjust AB so that AB = AC±2mm. For the installation of three-axle or multi-axle air suspensions, follow the method used for the first axle and so on. Adjust the front-rear axle distances according to the design plan: BD = CE±1mm, DF = EG±1mm (ensure the diagonals BE = CD±1mm, CF = BG±1mm). Once the brackets are positioned, fix them with tack welding.

2.1.1.2 Welding of Upper Airbag Support Bracket

For the welding position of the upper airbag support bracket, generally, using the axle centerline as the reference, translate backward to fix the longitudinal position of the upper airbag support bracket with a dimension of P2±1mm, and the lateral fixed position with a dimension of L2±1mm (refer to the design plan for P2 and L2 values). Take a straight square tube or channel steel, mark the dimension L2, place it on the pre-marked centerline of the upper airbag support bracket (the centerline of the bracket is marked, with the centerline of the two holes as the reference), fix it with tack welding, then place it on the frame and weld it to the frame according to the design dimensions.

Note: If a middle lift is required, please refer to section (2.4) for the installation position of the lift air spring upper bracket.

2.1.2 Bracket Reinforcement

After positioning the guide leaf spring bracket and the upper load-bearing airbag bracket, reinforcement of these brackets is mandatory to ensure sufficient strength of the suspension system during vehicle turning. For the shape and position dimensions of reinforcement parts, refer to materials such as the air suspension accessory drawings provided by our company.

2.1.2.1 Reinforcement Position of Guide Leaf Spring Bracket and Frame.

2.1.2.2 Reinforcement Crossbeam for Upper Load-Bearing Airbag Bracket,Fix the position according to the designed height of the upper load-bearing airbag bracket, and reinforce the connection between the upper airbag bracket and the frame.

2.1.3 Welding of Steel Wire Rope Pin Shaft

Weld the steel wire rope pin shafts symmetrically directly above the axle, with the cotter pin holes oriented vertically (up and down). Reinforce with triangular support plates, and ensure all welds are full penetration welds.

2.1.4 Installation of Height Valve Bracket

For three-axle suspension systems, the height valve is installed on the middle axle; for two-axle suspension systems, it is installed on the rear axle. The height valve is generally fixed on the reinforcement crossbeam of the upper load-bearing airbag bracket. The installation surface is positioned 70mm offset from the centerline of the fixed crossbeam toward the co-driver's side.

Note: If a lift axle is equipped, the height control valve must not be installed on the lift axle.

2.1.5 Installation of Load-Sensing Valve Bracket

Load-sensing valves are typically used in vehicles with a hybrid assembly of air suspension and mechanical suspension. During installation, the load-sensing valve bracket must be fixed on the mechanical suspension axle adjacent to the air suspension. Refer to the design specifications for installation dimensions and positions.

Note: The load sensing valve is not allowed to be installed on the air suspension axle.