The influence of laser surface texture on the tribological properties of friction layer materials in ultrasound motors

Abstract

Ultrasonic motors are typically driven by the dry friction force between the rotor and the stator; the friction pairs’ high friction coefficient and low wear rate are two essential elements for improving the operational stability with longer service life. In this research article, high-precision microgroove arrays were manufactured on the surfaces of the stator and rotor of the TRUSM60 ultrasonic motor using laser machining. Dry friction and wear tests between the stator and the rotor were carried out with pin-on-disc using HSR-2M high-speed reciprocating friction and wear tester to determine the tribological properties of the ultrasonic motor. According to a different distribution of microgrooves on the two contact surfaces, the influence of smooth surface, single-sided texture, and double-sided texture on the friction pair's friction performance were discussed. The results show that the textured surface can substantially increase the coefficient of friction of the contact surface and reduce the rate of wear. The one-sided textured phosphor bronze surface with a microgroove width of 200μm and an area ratio of 20% had the highest coefficient of friction of 0.334 and a friction increase rate of 36.3%. Similarly, the single-sided textured Polyimide surface attained the highest friction coefficient of 0.355 and friction increase rate of 44.9% when the groove width is 150μm and the area ratio is 30%. A higher friction coefficient of the double-sided texture can be obtained through reasonable parameter configuration than the single-sided texture. The included angle of 0° between the two textured surfaces produced the highest friction coefficient of 0.368 and the wear rate of the phosphor bronze and polyimide surfaces were 2.01 × 10−4 mm3/N-m and 1.949 × 10−3 mm3/N-m, respectively. The result provides an essential benchmark for enhancing the tribological performance of ultrasonic motors and increasing the output torque.

Disk cutter wear prediction of TBM considering sliding and rolling friction

“…When the tangential force increases to the limit friction force, the object will be at the moment of sliding, and there will be a trend of relative displacement between the contact points. The interaction of the material surface roughness peaks, especially the harder roughness peaks penetrate and cut the softer material to form a groove effect, resulting in the loss of sliding friction energy [24,25]. The function of sliding friction can be expressed as follows:…”

Improvement of current-carrying tribological behaviour via laser surface texture

“…Nowadays, Laser Surface Texturing (LST), has become a well-known surface to improve the tribological characteristics of contact interface. Researchers have carried out a great deal of research on the tribological behaviour related to LST [13][14][15][16][17][18]. However, these studies are all carried out in the case of no current input, and the research related to LST under current-carrying condition is rarely reported.…”

Effect of groove textures on tribological properties of 40CrNiMoA steel under starved grease lubrication

“…Current studies have shown that the friction properties of micro-grooves are largely influenced by groove geometry. If the geometrical characteristics of the surface texture are not designed properly, it will not only be unable to improve the friction and wear of material surfaces but will even cause more severe friction and wear on the surface than non-textured surfaces [22][23][24][25]. Segu et al [26] developed multi-shape laser surface textured steel surfaces to improve the friction and wear performance under dry and lubrication conditions.…”