Improved energy conversion efficiency of the ultrasonic motor with surface texture

Abstract

Purpose This paper aims to investigate the effect of frictional materials and surface texture on the energy conversion efficiency and the mechanical output performance of the ultrasonic motor (USM). Design/methodology/approach A newly designed testing system was set up to measure the mechanical output performance of the USM. The influence of different frictional materials on the output performance of the USM was studied under the same assembly process and parameters. The surface texture was fabricated by laser ablation processing. The effects of surface texture and input parameters on the energy conversion efficiency and mechanical output performance of the USM were studied. Findings The results show that polyimide (PI) composites as frictional material can significantly improve the output performance of the USM compared to polytetrafluoroethylene (PTFE) composites. When the pre-load is 240 N, the energy conversion efficiency of the USM using textured PI composites as frictional material can reach 41.93 per cent, increased by 29.21 per cent compared to PTFE composites, and the effective output range of the USM is increased to 0.7-1.1 N m. Besides, the pre-load and surface texture have a great influence on the output performance of the USM. Originality/value PI composites can improve the mechanical output performance of the USM. Surface texture can also improve the interface tribological properties and the energy conversion efficiency based on the advanced frictional materials, which will contribute to the increment of the output performance of the USM under the same input conditions.

Influence mechanism of surface texture on the output performance of an ultrasonic motor

“…Laser surface texturing and flexible mask micro electrolysis was used to fabricate the surface textures on the friction material and stator, respectively, with the parameters in Tables 3 and 4, respectively. Based on our previous results, the area density of all textures was set to 7.06% (Liu et al , 2018b; Liu et al , 2019). The friction materials were textured with circular dimples and the stator was textured with square, circular or elliptical dimples.…”

“…In previous studies (Liu et al , 2018a, 2018b; Liu et al , 2019), the authors fabricated surface textures on tribo-pairs of a TRUM-60 and investigated the effect of these textured surfaces on the output performance. However, few studies have investigated the actual mechanism by which surface texture influences the contact interface of a USM.…”

Tailored surface textures to increase friction—A review

“…Therefore, the COF dictates the output torque of USMs. Liu et al [128] used nanosecond laser texturing to produce different textures on polyimide plates used as friction material in USMs. They verified the highest COF for dimples with a diameter of 300 μm and area coverage of around 7%.…”

Ultrasonic Motors Structural Design and Tribological Performance -A Review

“…Based on the results, the authors proposed a model to predict the wear of friction materials under ultrasonic vibration conditions. A series of the experiments were performed by Liu et al [56] to study the tribological properties of polyimide (PI) and polytetrafluoroethylene (PTFE) composites of the USM. The influence of surface texture on the energy conversion efficiency, output torque, and other mechanical output performance was also investigated.…”

“…5(c). Xiaoliang et al [56] have developed a new test system to measure the USM's mechanical performance. The rotation sensor and torque sensor measured the USM output speed and torque at various loads.…”