Theoretical and experimental study of friction torque of ball screw mechanism considering lubrication

Author(s):  
Min Wang ◽  
Bo Chai ◽  
Tiewei Sun
2021 ◽  
pp. 1-18
Author(s):  
Lu-Chao Zhang ◽  
Chang-Guang Zhou

Abstract The coefficient of friction (COF) is a key factor to estimate the performance of ball screws. Pieces of research focus on the experimental study of the COF, leading to the COF chosen empirically in many studies. To acquire the COF of the HJG-4010, a measuring system is conducted to detect the friction torque under different preloads and rotational speeds and the effects of the applied axial load and rotational speed on the COF are analyzed. By the curve fitting method, the Stribeck curve of the ball screw is obtained. The experimental results show that the lubricating state can be divided into two categories: the mixed lubrication state, and the hydrodynamic lubrication state. This study is beneficial to choose a suitable working condition for a different performance of the ball screw.


2021 ◽  
Vol 28 (5) ◽  
pp. 1357-1376
Author(s):  
Bao-bao Qi ◽  
Qiang Cheng ◽  
Shun-lei Li ◽  
Zhi-feng Liu ◽  
Cong-bin Yang

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879916 ◽  
Author(s):  
Kai Chen ◽  
Li Zu ◽  
Li Wang

Ball screw is a mechanical device widely used in mechanical field. The reverse clearance of ball screw will reduce its precision. In order to eliminate the reverse clearance, it is necessary to apply preload to the ball screw. It is very difficult to measure the preload in real time, and the data are large and time-consuming. By using machine learning method to predict and supervise preload, the changing trend of working condition of ball screw can be evaluated in advance, and the working precision of screw is controlled, which has important engineering significance. In this article, the relationship between the preload and the friction torque is obtained through theoretical derivation and experimental verification. Then, the support vector machine is used as a tool to model the friction torque of ball screw with the parameters of material, lubrication, and revolution, and predict the value and trend of preload to complete the supervision and prediction of the preload of the ball screw. By comparing the experimental results, it is proved that the support vector machine is feasible in predicting and supervising the attenuation of the preload of ball screw.


2019 ◽  
Vol 72 (4) ◽  
pp. 541-548 ◽  
Author(s):  
Liang Yu ◽  
Biao Ma ◽  
Man Chen ◽  
He Yan Li ◽  
Jikai Liu

Purpose This paper aims to study and compare the friction stability of wet paper-based clutches with regard to the radial grooves (RG) and waffle grooves (WG). Design/methodology/approach This paper presents an experimental study of a wet clutch concerning the effect of groove patterns on the friction torque and surface temperature. The friction stabilities of RG and WG are investigated with the applied pressure, rotating speed and automatic transmission fluid (ATF) temperature taken into consideration. Findings The friction torque and surface temperature of WG are larger than those of RG under the same operating condition. The friction torque difference between RG and WG grows with the increase of applied pressure and narrows with the increase of ATF temperature. Additionally, their temperature difference expands via increasing the rotating speed and ATF temperature or reducing the applied pressure; in this way, not only the variable coefficient difference between RG and WG can be narrowed, but also the friction stability of the clutch can be improved dramatically. Originality/value This paper explains the thermodynamic differences between RG and WG; moreover, it is verified experimentally that WG has a better friction stability than RG.


2019 ◽  
Vol 149 ◽  
pp. 1345-1358 ◽  
Author(s):  
Guan Qiao ◽  
Geng Liu ◽  
Shangjun Ma ◽  
Yawen Wang ◽  
Pin Li ◽  
...  

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882073
Author(s):  
Lu-Chao Zhang ◽  
Li Zu

Based on the theory of thermal transmission, this article provides a new method to acquire the friction coefficient in ball screw mechanism. While the screw is in thermal equilibrium, the heat absorption is equal to the heat dissipation. The heat absorption is able to be achieved by calculating the heat energy due to the friction at the contact area and the heat dissipation can be calculated by the law of thermodynamics. When the temperature rise is determined, the heat dissipation can be obtained and the friction coefficient in ball screw mechanism can be calculated further. In order to confirm the validity of this method, a measuring system is constructed to obtain the temperature rise of ball screws. The experimental results show that the temperature rise has the same tendency with the theoretical values depending on this model. Therefore, it can be exploited to predict the temperature rise of ball screws in the rated life cycle when the ball screw is under the condition of thermal equilibrium. Furthermore, this model can be used to evaluate the mechanical efficiency, which is an important parameter for the performance of the ball screw.


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