Some Information about Axle Scale

Axle scale is a vehicle weighing equipment by weighing the single axle weight and accumulating the whole axle group weight. The main principle of measurement is that the weighing platform is connected with the weighing sensor. The weighing sensor consists of elastomer, resistance strain gauge, lead and shell. When the vehicle passes through the weighing platform, the elastomer bears gravity and has a deformation proportional to gravity. The resistance strain gauge sticks to the elastomer and has the same deformation as the elastomer. Thus, the resistance variable is generated. Under the action of the bridge circuit, the output voltage of the bridge circuit is proportional to gravity.

1. Axle Scale structure and Axle Scale workings principle

 There are two structural forms of axle load scale. One is the bending plate type’s axle load scale, which consists of bending plate elastic elements, load-bearing frame, end pressure plate, fastening screw and so on. Its core component is a bending beam with two long slots symmetrically machined at a certain width near two long edges on a long strip of alloy steel plate, which forms a bending beam with two fixed-supported centers bearing concentrated loads from the longitudinal direction. The second is the shear plate type axle load scale, whose core component is the shear plate elastic element. Its blank is 2A12 hard aluminium alloy plate in the artificial aging state of cold drawing, solid melting and heat treatment. The middle depression area is processed along the length direction at the bottom of the plate, and the bearing support area with enough area is formed on both sides of the length direction naturally, which makes the hard aluminium alloy plate become the plate bridge type scale.

Bending plate elastic element measures the bending stress of wheels on each bending beam. From the analysis of two resistance strain gauges of a bending beam to n resistance strain gauges of multiple beams in the same long groove, it is concluded that loading at any position in the measuring range of bending plate elastic element basically keeps the total output unchanged, that is, the change of loading point has no effect on the output sensitivity.

The shear plate elastic element measures the tension and compression double principal stress caused by shear stress between the top and bottom of the plate when the wheel is pressed in the strain zone. It does not respond to the bending stress at the same time. It is the same as the bending plate elastic element, and the change of loading point has no effect on the output sensitivity. 

2. Characteristics and Application

Because of the improvement of structure design and manufacturing technology, the measuring accuracy, allowable speed and working life of bending plate and shear plate axle load scales have been greatly improved. Therefore, they can lead the way in the inspection and supervision system of axle load quality of highway vehicles, and have been widely used as wireless axle scale.