Cooling of Linear Direct Drives in Precision Engineering with Piezo Fans

Abstract:
Linear direct drives are used when high position accuracy and high dynamics in linear movements are required. During operation, drives can develop high temperatures which limit their performance. Especially drives with a moving coil have a poor thermal connection to the drive. This makes it difficult to transfer the heat caused by ohmic losses in the coil. In order to increase the power of the drive, an additional cooling system is required. The most commonly used systems are radial or axial fans, which increase the convection coefficients on the surface that needs to be cooled. These fans usually consist of a small DC motor, a bearing system and a fan impeller. These mechanical components, in particular, have an enormous effect on miniaturization, since the influence of friction increases with the downsizing of the system. This affects the efficiency and reliability of the cooling system. In frictionless systems, such as the piezoelectric fan or the piezoelectric Dual Cooling Jet, an air flow is generated via the piezoelectric excitation of a cantilever beam or a membrane at resonant frequency. These cooling systems therefore show high potential for the efficient and reliable cooling of linear drives in precision engineering.