Research On Anisotropic Friction Material For Ultrasonic Motor

Ultrasonic motor is a new kind of driving machine which obtains dynamic in virtue of use friction to transfer elastic ultrasonic vibration. Friction material is a key technique of ultrasonic motor. Common friction material is isotropic at the present time. According to the characteristics of the contact friction - transmission of ultrasonic motor drive, the interface of stator and rotor has not only some contact deformation but also good interface transmitting force performance, thereby the design of anisotropic friction material and the research of anisotropic friction material on the performance of ultrasonic motor is theoretical and practical important for better revealing the driving mechanism and the development of the suitable motor friction material.Fiber reinforced resin anisotropic material is mainly researched in this paper. 4 fibers and 3 resins are chosen to manufacture different anisotropic extent material by different fiber tropism and multiplex tropism. Plate mould is designed, and facture flows are studied of different element, dosage and fiber tropism to manufacture different EH/EV anisotropic material. Elastic modulus in fiber array direction and hardness are also researched. M200 is made use to research Friction and wear of anisotropic material and Metallography microscope is also used to analyze the wear surface. The result shows that friction coefficient and wear is high when fiberglass is N tropism compared with A and AP tropism, the P and AP multiplex tropism is lowest. Friction and wear of materials filled with supramoly and graphite decreases because of transfer film is formed on the wear surface filled with supramoly and self-friction film is formed on the wear surface filled with graphite.The ultrasonic micro-driving test bed is made use of to simulate the driving force and positive pressure of ultrasonic motor. Different EH/EV matches of the friction material on the performance of ultrasonic motor is also researched . The results show that when the EH/EV of friction material ranges from 0.71 to 1.42, the driving force and positive pressure would increase at first then decrease. The value of driving force and positive pressure would achieve maximum when the specific value is 1.24, also the effect of driving is best. The anisotropic friction materials filled with supramoly and graphite on the performance of ultrasonic motor is researched and the results show that the value of positive pressure remains basically unchanged and the value of positive pressure decreases. When the mass percents of two materials are the same, the driving effect of friction material filled with supramoly is better than that of friction material filled with graphite. but the wear rate of friction material filled with graphite is lower than that of friction material filled with supramoly.