An improvement of micromechanical accelerometers (MMA) is relevant due to the constant expansion of their applications and the use of such devices in increasingly demanding conditions. In the paper the sandwich designs of the sensitive element (SE) of a capacitive micromechanical accelerometer (MMA) with folded springs have been studied from the point of view of ensuring the high sensitivity to acceleration, resistance to temperature change and the presence of residual mechanical stresses in the structures while providing the relative simplicity of their manufacturing technology. The modeling has been executed in ANSYS program. The gaps between the movable and stationary electrodes are increased compared to analogs up to 20 microns. It has been shown that the high sensitivity to changes of the acceleration is provided due to the optimization of the sensitive element design, using folded springs with lower values of stiffness coefficient. It has been determined that the capacity change under the action of acceleration along the working axis ( Z ) is almost 20 times more than changes in capacity along axes X and Y and the effect of temperature in the range of -40 ºC to 85 ºC on changes in capacitances along the working axis ( Z ) is small ±0.0025 - 0.003 pF. The mechanical stresses, which occur in constructive elements of the sensitive element under acceleration to 50 g, do not exceed 2.29 MPa, while silicon has strength 440 MPa. The natural frequency of oscillation of the second mode of the sensitive MMA does not affect the natural frequency of oscillation of the first mode of the sensitive element due to a significant difference of these frequencies approximately by 2 kHz. The analysis has shown that the studied sandwich constructions are characterized by high sensitivity and stability of parameters with relatively simple manufacturing.
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