With the change of time, the rapid development of China's electronic weighing instrument, in the field of large scales, the heavy-duty long-size carrier truck scale is generally put into use, and some new problems have appeared in front of us. Especially because the steel structure carrier is affected by the thermal expansion and contraction and the length changes, one will directly make the load cell unable to transmit the force value vertically; the second will affect the gap size of the limit device, and even die. In order to ensure the accuracy of the metering performance, what structure of the load cell should be selected becomes a problem when the customer purchases. At present, the weighing sensors used on large scales at home and abroad include: column load cell, bridge load cell, double shear beam ring load cell, axisymmetric torsion ring type load cell, spoke type load cell, etc. .

Characteristics of several load cells

1, column load cell

Advantages: compact structure, strong overload capability, high natural frequency, fast dynamic response, convenient installation and low manufacturing cost.

Disadvantages: resistance to lateral and eccentric load is poor (double diaphragm structure is better), inherent linearity is poor, and the load cell is not easy to fix and rotate.

2, bridge load cell

Advantages: Insensitive to change of loading point, good anti-offset performance, good inherent linearity, convenient installation, fixed and non-rotating load cell, low manufacturing cost.

Disadvantages: The center of gravity is high and the overload capability is poor. It is difficult to achieve a high accuracy level for weighing instruments with large weighing.

3, double shear beam ring load cell

Advantages: The anti-offset performance is good, and the load cell is fixed and does not rotate.

Disadvantages: complicated structure, troublesome installation, high manufacturing cost, poor overload capability, large space occupation, and such products are not suitable for manufacturing large-scale structures.

4, axisymmetric torsion ring type load cell

Advantages: compact structure, small size, low height, light weight, good inherent linearity, high accuracy, no deformation or minimal deformation under load, almost no hysteresis, insensitive to eccentric load and lateral load, input and output impedance The large, load cell is fixed and does not rotate.

Disadvantages: The installation is slightly complicated and the manufacturing cost of the accessories is high.

5, spoke type load cell

Advantages: strong anti-offset and lateral load capacity, strong overload capability, unaffected by the loading point and support boundary, uniform stress distribution, good linearity, and the weighing sensor is fixed and does not rotate.

Disadvantages: mechanical processing is difficult, manufacturing cost is high, inherent hysteresis is large and difficult to control.

It can be clearly seen from the above five types of load cell structures that only the column load cell elastomer moves in use with the sway of the carrier, that is, the vertical load cell cylinder during installation, due to the carrier The length of thermal expansion and contraction changes, the cylinder of the load cell is offset, which causes the force to generate a component force, so that the weighing sensor has a weighing error. The other four types of load cells are fixed because the elastomer is fixed. When the thermal expansion and contraction affects the length change of the carrier and the sloshing of the carrier, only the indenter is offset, and the elastic body that transmits the force does not follow. The movement of the carrier changes, so that the force on the load cell can also be transmitted vertically, and the influence on the weighing performance of the truck scale is relatively small; at the same time, since the elastic body does not sway with the carrier, the elastic body does not rotate. The cable will not wrap around the elastomer.

Weighing sensor, weighing module, weight transmitter, weighing control instrument, weighing application system

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