1 This article is designed ring-type ultrasonic motor vibrator micro ring beam structure, BARS beam symmetrical arrangement of two sets of drive gear (to increase the thrust of the motor), and thus suitable to be made self-propelled structure. The annular transducer arranged by its symmetry plane is connected to the flexible hinge support structure, to achieve the output of the driving force. The transducer ring-containing elastomer, a drive tooth, the piezoelectric ceramic sheet, a flexible hinge and the support structure. This structure is suitable for use under the premise of ensuring the necessary stiffness, dynamic design, completion of the selected plane bending mode frequency difference is minimized by the fine-tuning of the structural parameters.

The key to the design of such transducers are looking for the natural frequency of the two are equal (or close to) the same order bending vibration mode, make the drive teeth in a suitable geometric position in each modal in order to achieve equal to the frequency of use of two the same order the modal completion mover, opposite direction.

Due to the miniaturization of the motor, such that the transducer is less than 80 KH z **ultrasonic frequency** range available modal less. For the arrangement of the ceramic sheet, the vibration of the transducer type only the odd order to meet the design requirements of the bi-directional movement of the motor, the same modal less than 9 order has been beam segment two drive teeth on the design and difficult disposed. Taking all these factors, the 9-order bending vibration mode oscillator modes. Two inherent frequency of the **Piezoelectric Transducer** 9-order bending vibration modal (9) 60 690 H z and 60 694 H z, the frequency difference 4 H z (relative value of 0.003%, can be negligible ). If a simple harmonic signal excitation of a set of ceramic sheets (up and down as a group, as a group around), the transducer will toggle the rail movement in one direction; transducer Slide rail to when the excitation of a set of ceramic films, opposite direction. This driver program to some extent simplifies the beam standing wave ultrasonic motor low voltage electrical equipment should be based on the drive system has a variety of features. 2 transducer structure modal Under normal circumstances, the transducer, this completely symmetrical structure, of the same order of two bending vibration modes corresponding to the two frequencies are very different, which requires in the design process, by adjusting the the structure of the transducer to achieve the purpose of reducing the frequency difference. Peripheral structure of the oscillator is a square ring beam, straight beam and 90 arc segment. Arc over the wavelength is more evenly distributed, help drive the arrangement of the teeth.

Below the structural dimensions of the Table 1 is based, to investigate the structural parameters of the transducer on the bending mode of the transducer 9, two inherent frequency f 1, f 2, and its frequency difference f. Change four straight beam transducer segment length L, the two bending vibration frequency and frequency difference can be changed within a wide range. Table 3 gives the L 25. 6 26. 4 mm varies between the natural frequency of the finite element numerical calculation results to L = 26 mm, within 4 mm range, the frequency difference to both sides of gradually increases, the maximum error of 1.07%.

Compared with the general hinge has a smooth motion, without lubrication, no rollback empty drive, no friction, high precision, in the field of precision machinery, precision measurement, micron technology and nanotechnology widely used. In order not to affect the mode of vibration of the square ring oscillator, but also to ensure that the motor power output by the oscillator support structure, as the ring oscillator their support straight beam flexible hinge connection.

With flexible hinge supporting position and the structure changes, the modality of the transducer will be affected. The following is based on a 1 mm the adjustment step away from the oscillator B modal finite element analysis. Table 5 shows the support positional parameters z floating up and down from the center 4 mm near the 9th order natural frequency of the oscillator calculation results. The order modal a natural frequency f 1 gradually decreases to both sides of the frequency value f to the sides gradually increases, the frequency difference is gradually increased along. A slight change of its location on the frequency and the frequency differential is to have a certain influence (maximum 56%), which requires the processing has a high processing accuracy to ensure that the minimum frequency difference.

Although the frequency difference is very small, but due to the design herein standing wave ultrasonic motor is driven at the same frequency the motor forward and reverse movement, so if the resonant frequency can not be achieved in one direction, will affect its positive and negative direction of movement speed consistency. Therefore, in the design and processing should also try to meet the preferred structural parameters. Support structure in order to ensure sufficient rigidity to the ultrasonic motor starting, high positioning accuracy, the thickness of the flexible hinge should not be too small. The numerical results show that the vibration of the oscillator type has changed significantly when the thickness of the flexible hinge more than 0.8 mm, the wavelength becomes very uneven, the amplitude of different sizes, the frequency difference between the error of 1.89%. Occurrence of this The case has seriously affected the performance of the ultrasonic motor is basically impossible to work. The frequency difference can be seen from Table 7, the support structure size en = 0 5 mm, Min. Oscillator supporting structure parameters on the performance of the motor, in the design process should be of sufficient size deviation limit.

4 Conclusion This paper introduces one kind of new square ring-linear standing wave ultrasonic motor and oscillator structure parameters and flexible hinge support structure carried out a dynamic design with finite element software, to discuss the oscillator and the support of the main structure parameters of the vibration mode impact, and the frequency difference of the sensitivity analysis. Working modal transducer bending vibration, the use of the order modal two vibration type linear ultrasonic motor can be realized under the same driving frequency of positive first order surface 9, anti-motion. Using double-sided arrangement of the motor drive gear, the thrust of the motor can be increased.

Original articles such as reserved：SK ultraonic cleaner Blog

This link address：http://www.sksonic.com/ultrasonic/Ultrasonic-electric-equipment-oscillator-non-static-default.html