During the Piezo Electric measuring-procedure silicon crystals are elastically deformed, so that an electric load appears on its defined outside surfaces. This load is found to be proportional to the applied force.
Torque is measured using the shown ring-element. The single quartz disks are arranged in such a way, that an appearing tangential forces can be measured. The transducer carries a high pre-load which allows it to transfer the appearing torque through frictional resistance to the quartz elements. The single elements are arranged parallel, so that the appearing load is proportionally to the transferred torque. Since the insulation resistance of the charge amplifier and measuring instrument is of a certain size, the occurring load flows only gradually. Piezo-electric transducers are therefore only marginally suited for static measurement.
For the use in the screwdriving technology however, the Piezo transducer is very well suited because of its
- extreme high dynamic,
- an excellent linearity over a wide measuring range,
- its very small size,
- the non-existent wear-parts,
- its high rigidity
- and the
outstanding general measuring qualities.
Especially very high sampling rates (10 kHz) allow for the torque acquisition of hard screw-joints.
All DEPRAG measuring screwdrivers measure the reaction-torque, so that no measurement of movable parts is required. The use of Piezo torque measurement-cells are particularly well recommended for the use in stationary measuring platforms because of a rather large usable torque-range.
Our products are located in PDF Product Catalog D 3020.