Development of variable preload system for machine tool spindle using giant magnetostrictive material Terfenol-D actuator

Abstract

Applying a bearing preload of machine tool spindle produces positive effects, including increased stiffness, rotation noise reduction, increase in shaft precision, position adjustment during operation, and prevention of rolling element resonance and rotating slip, along with a significant extension of the bearing lifespan. A variable preload technique is a method that improves the bearing performance by appropriately varying the preload applied to the bearing according to the spindle rotation speed and machining condition. In this study, a novel variable preload method utilizing a Terfenol-D actuator has greater power and more displacement and force than those of other transducer materials such as piezo elements or nickel alloys. Terfenol-D has greater power and more displacement and more force. A prototype of a spindle for the variable preload system using Terfenol-D was fabricated, and the axial force and displacement of the bearing were measured during a running experiment. In order to assess whether the proposed variable preload device can effectively apply preloading to the bearing, a comparative analysis was conducted between the theoretical and empirically obtained values of the bearing axial direction displacement. Through the comparative analysis, the real applicability of the proposed structure was confirmed.

Study on high frequency magnetic energy loss of Terfenol-D rods with different structures

“…Currently, the most widely used transducers in industrial applications are magnetostrictive and piezoelectric transducers (Yao et al, 2020). Giant magnetostrictive materials (GMM) have large magnetostrictive coefficient, high energy density, and lower sound velocity; fast response speed, and strong load capacity; these characteristics determine that GMM is an excellent functional material for the development of high-power, large amplitude, and wideband ultrasonic processing systems, which make them suitable for many applications, including transducers, actuators, injectors, vibration energy collection (Deng and Dapino, 2017; Kim and Lee, 2020; Li et al, 2020; Xue et al, 2018).…”

Structure Design and Working Characteristics Analysis of Direct-Drive Giant Magnetostrictive Injector

“…Among them, the giant magnetostrictive actuator (GMA) [ 6 , 7 ], developed by using GMM as a transducing material, shows excellent driving characteristics and shows great application prospects in the field of fuel injection.…”

Negative Poisson’s Ratio-Spacer Design and Its Thermo-Mechanical Coupling Analysis Considering Specific Force Output

“…At present, mainly hydraulic, electromagnetic, and piezoelectric methods are being used worldwide in the studies on variable bearing preloads [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. For example, Jiang and Choi designed an adjustment mechanism based on the hydraulic preload force [ 2 , 3 ]; however, the use of hydraulic technology requires a complex hydraulic system, which is expensive.…”

“…However, this preload force adaptive adjustment method changed the structure of spindle shaft systems and had low versatility. Therefore, in 2020, Kim et al proposed another variable adjustment structure for spindle preload force using a Terfenol-D brake, which improves the response time and can adjust the spindle preload force within a certain range [ 7 ]. Razban et al proposed a spring structure that can vary with speed to adjust the spindle preload force based on speed [ 8 ]; however, this method requires an additional structure.…”