scholarly journals A new method to calculate the friction coefficient of ball screws based on the thermal equilibrium

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882073
Author(s):  
Lu-Chao Zhang ◽  
Li Zu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Mechanical Efficiency ◽  
New Method ◽  
Measuring System ◽  
Ball Screw ◽  
Heat Absorption ◽  
Screw Mechanism

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.

scholarly journals Prediction of the Thermal Elongation of the Ball Screw Mechanism under Various Rotational Speeds

2021 ◽  
Author(s):  
Lu-Chao Zhang ◽  
Yi Ou ◽  
Hu-Tian Feng
Keyword(s):  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Numerical Control ◽  
Ball Screw ◽  
Thermal Equilibrium State ◽  
Temperature Changes ◽  
Position Accuracy ◽  
Laws Of Thermodynamics ◽  
Thermal Transmission ◽  
Screw Mechanism

AbstractIn numerical control machines, the thermal elongation of the ball screw influences the position accuracy. Different rotational speeds lead to different temperature changes at different positions in a ball screw system. In this paper, a new method is proposed to calculate the temperature rise of different positions when the ball screw is in the thermal equilibrium state. The thermal transmission of ball screws is analyzed, and the heat generation and transfer coefficient are calculated based on the laws of thermodynamics. The function between the temperature rise and position is built by solving the thermal equilibrium differential equations. The thermal elongation is obtained after the temperature rise is calculated. In order to prove the validity of this model, a series of detection tests are conducted to obtain the temperature rise of a ball screw and the thermal elongation under different rotational speeds. The experimental results show that the realistic temperature rise and the thermal elongation agree well with the theoretical values.

Temperature rise characteristics of the valve-controlled adjustable damping shock absorber

2020 ◽  
Vol 21 (1) ◽  
pp. 111
Author(s):  
Fangwei Xie ◽  
Jinxin Cao ◽  
Erming Ding ◽  
Kuaidi Wan ◽  
Xinshi Yu ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Shock Absorber ◽  
Heat Radiation ◽  
Vibration Velocity ◽  
Outer Diameter ◽  
Dissipation Model ◽  
The Difference

The thermodynamic study of the valve-controlled adjustable damping shock absorber is conducted in order to solve the problem of oil leakage caused by excessive temperature rise of shock absorber. In this paper, the temperature rise of the valve-controlled adjustable damping shock absorber is analyzed from the perspective of energy conservation. Combined with the theory of fluid mechanics, the damping heat model is established, and the heat dissipation model of the shock absorber is established based on heat convection, heat conduction and heat radiation. The corresponding thermal equilibrium equation is established on the basis of damping heat and heat dissipation. The effects of vibration velocity, outer diameter, thickness and length of reservoir cylinder, and wind velocity on its thermal performance have been investigated. Specifically, temperature after thermal equilibrium will grow with the increase of vibration velocity and thickness of reservoir cylinder and degrade with the increase of outer diameter, length of reservoir cylinder and wind velocity. The higher the balance temperature, the shorter time is required to arrive thermal equilibrium. The difference between the experimental and simulation values of oil temperature after thermal equilibrium was not more than 2 °C, which verified the correctness of the theoretical model, while the experimental value in the process of temperature rise lagged behind the simulation value, which was mainly caused by the cumulative error of step-by-step iteration and the mechanical hysteresis in the experiment. The conclusions obtained can provide some references for the design of shock absorbers.

scholarly journals Investigation of the Transmission Accuracy of Ball Screw Considering Errors and Preloading Level

2021 ◽  
Author(s):  
Kai Wang ◽  
Chang-Guang Zhou ◽  
Yi Ou ◽  
Hu-Tian Feng
Keyword(s):  
Transmission Error ◽  
Measuring System ◽  
Ball Screw ◽  
Contact Deformation ◽  
Periodic Fluctuation ◽  
Manufacturing Errors ◽  
Screw Mechanism ◽  
The Difference ◽  
Novel Model ◽  
Eccentricity Error

Abstract Transmission accuracy is one of the most important parameters in ball screw mechanism (BSM), however, very few researches can be found on the transmission accuracy modelling for BSM. Therefore, this paper proposes a novel model to predicate the transmission accuracy of BSM considering the manufacturing errors, installation errors, as well as the errors due to the contact deformation under different loading status. Meanwhile, the transmission accuracy of a typical BSM under five different preloading levels is measured on the basis of a transmission accuracy measuring system. The experimental results show that the difference is 21.6% under no preload condition, and is less than 11% under different preload conditions, largely owing to the uneven distribution of clearance can increase the travel deviation. Further analysis shows that the eccentricity error, which belongs to the installation error, is the most important factor, mainly generating the periodic fluctuation and amplitude of the transmission error. More importantly, the travel deviation increases with the increase of the preload, which indicates that the transmission accuracy of the BSM deteriorates when the load is increased.

Kinematic Analysis of the Ball Screw Mechanism Considering Variable Contact Angles and Elastic Deformations

2003 ◽  
Vol 125 (4) ◽  
pp. 717-733 ◽  
Author(s):  
Chin Chung Wei ◽  
Jen Fin Lin
Keyword(s):  
Present Model ◽  
Ball Bearing ◽  
Normal Force ◽  
Mechanical Efficiency ◽  
Contact Angles ◽  
Ball Screw ◽  
Elastic Deformations ◽  
Contact Areas ◽  
Screw Mechanism ◽  
Theoretical Analyses

The theoretical analyses developed by Lin et al. 6 for the kinematics of the ball screw mechanism have been partly adapted for the present study. In order to better understand the sliding behavior arising at two contact areas, the analyses of a ball bearing, while accounting for elastic deformation, are modified through coordinate transformations prior to their applications to the analyses for the ball screw mechanism. The influence of differing the parameters such as friction coefficient, normal force acting on the ball, and contact angle on a ball-screw’s mechanism at two contact areas are evaluated. The results of the ball-screw’s mechanical efficiency achieved by the present model are displayed to compare with those evaluated based on the model of Lin et al. Substantial differences exist in the results evaluated by these two models, especially those created at high screw rotational speeds.

Research of the Technology Based on Fiber Bragg Grating for Measurement of Temperature Rise of Electrical Appliances

2012 ◽  
Vol 571 ◽  
pp. 200-204
Author(s):  
Zhao Xi Wu ◽  
Yu Zhan Wei ◽  
Jian Cui ◽  
Shui Sheng Wang ◽  
Xiao Peng Dong
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Temperature Rise ◽  
Electromagnetic Interference ◽  
Measurement Method ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Experimental Results ◽  
New Method ◽  
Measuring System

A new method of using fiber Bragg gratings as the sensing elements in the measurement of temperature rises of electrical appliances is proposed in this paper. Comparing with the conventional measurement method with thermocouples, the new method can overcome problems such as electromagnetic interference, hazard of electrical leakage, etc. The characteristics and key components employed in the measuring system are analyzed and discussed. The experimental results show that the temperature rises of electrical appliances under test can be obtained quickly and accurately with the specifically designed sensors made by optical fiber Bragg gratings.

Temperature Rise Times in Pneumatic Tires

1976 ◽  
Vol 4 (3) ◽  
pp. 181-189 ◽  
Author(s):  
S. K. Clark
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Transfer Coefficients ◽  
Pneumatic Tire ◽  
Heat Transfer Coefficients ◽  
Idealized Model ◽  
Pneumatic Tires

Abstract An idealized model is proposed for heating of a pneumatic tire. A solution is obtained for the temperature rise of such a model. Using known thermal properties of rubber and known heat transfer coefficients, the time to reach thermal equilibrium is estimated.

Precision loss of ball screw mechanism under sliding-rolling mixed motion behavior

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

New Method to Determine the a-Si:H Pin Diode Series Resistance by Noise Measurements

1998 ◽  
Vol 507 ◽  
Author(s):  
F. Blecher ◽  
K. Seibel ◽  
M. Hillebrand ◽  
M. Böhm
Keyword(s):  
Series Resistance ◽  
Partial Information ◽  
Low Noise ◽  
Operating Conditions ◽  
New Method ◽  
Measuring System ◽  
Pin Diode ◽  
Noise Current ◽  
Current Voltage ◽  
Noise Measurements

ABSTRACTThe series resistance limits the linearity of photodiodes and decreases the efficiency of solar cells. It is usually determined from IV-measurements for moderate and high forward current density. This method, however, provides only partial information about Rs, since the series resistance depends on the operating point. An alternative method is based on noise measurements. System noise of the measuring system with a low-noise current-voltage converter has been investigated. A new method for extraction of photodiode series resistance from noise measurements is suggested. Noise measurements are carried out for a-Si:H pin diodes. The series resistance of an amorphous pin diode has been extracted for different operating conditions using the new measurement method.

Research on Modeling Method of Runway Frictional Coefficient Measuring Vehicle Based on Impedance Diagrams

2011 ◽  
Vol 214 ◽  
pp. 133-137 ◽  
Author(s):  
Xu Dong Shi ◽  
Shou Wen Shi ◽  
Lu Zhang ◽  
Jian Li Li
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Measurement Data ◽  
Frictional Coefficient ◽  
Modeling Method ◽  
Measuring System ◽  
Discrete Fourier Transformation ◽  
Measuring Error ◽  
Impedance Diagram ◽  
Airport Runway

Airport runway friction coefficient is an important parameter to evaluate the quality of runway which is usually measured by runway friction coefficient measuring vehicle. In order to reduce the airport runway friction coefficient measuring error which comes from runway vibration caused by road roughness and vehicle its own structural characteristics, an impedance diagram is used to model the suspending system and measuring system of the measuring vehicle. The power spectral density of pavement and inverse discrete Fourier transformation are introduced to model runway surface roughness as excitation input. The rationality of the stimulating established model is validated by comparing with an airport runway surface roughness measurement data. Runway friction coefficient measuring vehicle′s measuring error can be reduced and the measurement accuracy can be improved by using the impedance diagram modeling method.

Experimental study on friction coefficient and temperature rise of heavy-load grease-lubricated spherical plain bearings with surface texture

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinlong Shen ◽  
Tong Zhang ◽  
Jimin Xu ◽  
Xiaojun LIU ◽  
Kun Liu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Surface Texture ◽  
Tribological Performance ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Roughness Parameters ◽  
Heavy Load ◽  
Friction Coefficients ◽  
Content Type

Purpose This paper aims to improve the tribological performance of grease-lubricated spherical plain bearings (SPBs) under heavy load, dimple-type textures were prepared by laser on the outer surface of the inner ring. The influence of roughness parameters of a textured surface on reducing friction coefficient and temperature rise was also explored. Design/methodology/approach This study adopts a laser processing method to fabricate dimple-type textures. Three-dimensional roughness parameters were used to characterize the textured surfaces. The friction coefficients of five SPBs with surface texture and one original commercially available SPB without surface texture under different nominal loads were measured on a self-established test rig. The data of temperature rise were obtained by nine embedded thermal couples. Findings The results indicate that SPBs with textures generally exhibit lower friction coefficients than the original SPB without textures. The dimple depth has a significant influence on improving the tribological performance, which coincides with the analysis by surface roughness parameters. A textured surface with negative Ssk and high Vvc has the minimum temperature rise. Originality/value As it is too difficult to arrange sensors into heavy-load SPBs, there are few reports about the temperature characteristics. Through nine embedded thermal couples, the distribution of temperature rise on the inner ring of SPBs was given in this study. The positive effect of surface texture on reducing temperature rise and friction coefficient was verified, which is beneficial for the design of heavy-load SPBs.

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