Prediction of the friction torque in grease lubricated angular contact ball bearings using grey system theory

Baomin Wang,Chao Gao,Zaixin Wu,Hongqin Liu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

The development of special grease makes it possible for angular contact ball bearings to operate at high speed and temperature; however, as an important performance parameter, friction torque of bearings lubricated with grease is much greater than that of bearings lubricated with oil-air, and heat generation due to frictional loss is also greater, so it is necessary to predict the friction torque occurring in grease lubricated angular contact ball bearings. Based on grey system theory, a new prediction methodology for bearing friction torque is proposed which capitalizes on the notion that the information about friction torque of angular contact ball bearing is generally poor, incomplete and uncertain. A grey prediction model, GM (1, N) model, is presented to predict the friction torque in grease lubricated angular contact ball bearings. Several experiments on the friction torque of grease lubricated angular contact ball bearings were conducted to model and validate the effectiveness of the GM (1, N) model through on-line and off-line approaches. Experimental results show that about 90% of bearing friction torque under varying speed can be predicted in the on-line prediction; above 85% of bearing friction torque under varying speed and different loads can be predicted in the off-line prediction. Comprehensive analysis shows that, the GM (1, N) model performs very well for both modeling data and model validation data under different loads, varying bearing speed and work cycles, the proposed methodology can be used to predict bearing friction torque with good accuracy and robustness.

롤러의 형상 불확실성을 고려한 테이퍼 롤러 베어링의구동마찰토크 평가

박정수,이승표 한국트라이볼로지학회 2023 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.39 No.5

A bearing is a mechanical component that transmits rotation and supports loads. According to the type of rotating mechanism, bearings are categorized into ball bearings and tapered roller bearings. Tapered roller bearings have higher load-bearing capabilities than ball bearings. They are used in applications where high loads need to be supported, such as wheel bearings for commercial vehicles and trucks, aircraft and high-speed trains, and heavy-duty spindles for heavy machinery. In recent times, the demand for reducing the driving friction torque in automobiles has been increasing owing to the CO2 emission regulations and fuel efficiency requirements. Accordingly, the research on the driving friction torque of bearings has become more essential. Researchers have conducted various studies on the lubrication, friction, and contact in tapered roller bearings. Although researchers have conducted numerous studies on the friction in the lips and on roller misalignment and skew, studies considering the influence of roller shape, specifically roller shape errors including lips, are few. This study investigates the driving friction torque of tapered roller bearings considering roller geometric uncertainties. Initially, the study calculates the driving friction torque of tapered roller bearings when subjected to axial loads and compares it with experimental results. Additionally, it performs Monte Carlo simulations to evaluate the influence of roller geometric uncertainties (i.e., the effects of roller geometric deviations) on the driving friction torque of the bearings. It then analyzes the results of these simulations.

볼의 자이로스코픽 모멘트와 원심력을 고려한 고속 볼베어링의 마찰 토크 해석 및 실험

장진우(Jinwoo Jang),장건희(Gunhee Jang) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10

A ball bearing is core component to design a rotor-bearing system. Friction loss of ball bearings is one of major energy loss in the rotor-bearing system, and predicting the friction torque of ball bearings is required to design a motor with low power consumption. Force equilibrium equations and geometric compatibility equations of a ball bearing are solved to calculate dynamic characteristics of a ball bearing. Friction torque is calculated by Palmgren and SKF ball bearing friction models with simulated contact angle result. In experiment, power loss of a motor is measured to calculate the friction torque of a ball bearing. The research shows that Palmgren and SKF ball bearing friction models are in good agreement with the experimental result, and the friction torque of a ball bearing is dominantly affected by preload and rotating speed.

Testing of Load Capacity of a Foil Thrust Bearing

Choong Hyun Kim,Jisu Park 한국트라이볼로지학회 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing takeoff and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean takeoff rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

1차 데드비트 토크 관측기를 이용한 IPMSM에 연결된 베어링 고장 진단 방법에 대한 연구

윤인식,배홍주,김승택,오귀운,고종선 대한전기학회 2023 전기학회논문지 Vol.72 No.10

Ball bearings are used in many mechanical devices with dynamic characteristics. When a failure occurs in a motor or pump, there are many failures due to the ball bearing. So, research on the diagnosis of ball bearing failures is being actively conducted. When a ball bearing fails, vibration occurs due to the natural frequency component of each part, which increases the friction between the ball bearing and the rotating shaft. This increases the load torque applied to the rotating machine performing rotational motion. In this paper, the torque was observed through the first order deadbeat torque observer for fault diagnosis of ball bearings connected to the IPMSM, and then it is filtered with BPF. The filtered value is used to detect the magnitude in the failure frequency band, and it is applied to the failure diagnosis algorithm to determine whether there was a failure. The proposed fault diagnosis algorithm was verified through simulation using MATLAB/Simulink. In addition, the fault diagnosis algorithm was verified by attaching a bearing housing to the M-G set consisting of 4 IPMSM and 5.5 IM.

초탄성 및 점탄성 물성을 고려한 자동차용 휠 베어링 실의 드래그 토크 예측

이승표 한국트라이볼로지학회 2019 한국윤활학회지(윤활학회지) Vol.35 No.5

Wheel bearings are important automotive parts that bear the vehicle weight and translate rotation motion; in addition, their seals are components that prevent grease leakage and foreign material from entering from the outside of the bearings. Recently, as the need for electric vehicles and eco-friendly vehicles has been emerging, the reduction in fuel consumption and CO2 emissions are becoming the most important issues for automobile manufacturers. In the case of wheel bearings, seals are a key part of drag torque. In this study, we investigate the prediction of the drag torque taking into consideration the hyperelastic and viscoelastic material properties of automotive wheel bearing seals. Numerical analysis based on the finite element method is conducted for the deformation analyses of the seals. To improve the reliability of the rubber seal analysis, three types of rubber material properties are considered, and analysis is conducted using the hyperelastic material properties. Viscoelastic material property tests are also conducted. Deformation analysis considering the hyperelastic and viscoelastic material properties is performed, and the effects of the viscoelastic material properties are compared with the results obtained by the consideration of the hyperelastic material properties. As a result of these analyses, the drag torque is 0.29 Nm when the hyperelastic characteristics are taken into account, and the drag torque is 0.27 Nm when both the hyperelastic and viscoelastic characteristics are taken into account. Therefore, it is determined that the analysis considering both hyperelastic and viscoelastic characteristics must be performed because of its reliability in predicting the drag torque of the rubber seals.

Testing of Load Capacity of a Foil Thrust Bearing

김충현,박지수 한국트라이볼로지학회 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing takeoff and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean takeoff rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

Testing of Load Capacity of a Foil Thrust Bearing

Kim, Choong Hyun,Park, Jisu Korean Tribology Society 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

In this study, the performance of foil thrust bearings was investigated by performing bearing take-off and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean take-off rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

Cage Design Development for Low Oil Agitation Torque using CFD

Jungsoo, Park(박정수),Jeongsik, Kim(김정식),Junhwan, Hwang(황준환),Changgi Lee(이창기) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6

In the high speed ball bearing used to EV motor, the friction torque reduction is the essential design factor for fuel efficiency of power train system. In contradiction with friction torques such as a loaded dependent torque from rolling element and a frictional torque due to EHL, the standardization of friction torque of oil agitation torque is limited due to variable cage design. It would be available to verify test. Recently the implement of CFD has been reduced the time consumption of cage development by reducing test verification. This study utilizes CFD in order to expedite development of cage for high speed ball bearing. The simplified model of CFD is based on previous research in this study and a new cage design develop by utilizing CFD. In this approach, the developed cage design is available to show the friction torque reduction in the friction torque test.

Improved Formulation for Sliding Friction Torque of Deep Groove Ball Bearings

리베라 길버트(Gilbert Rivera),통반칸(Van-Canh Tong),홍성욱(Seong-Wook Hong) Korean Society for Precision Engineering 2022 한국정밀공학회지 Vol.39 No.10

This paper presents an improved formulation, to estimate the sliding friction torque of deep groove ball bearings (DGBBs). Running torque of rolling element bearings, is directly associated with heat generation in rotating machines. Among the components of running torque, sliding friction is a major friction source in ball bearings. For DGBBs, sliding friction is dominated by spinning and differential sliding between balls and races. This paper addresses the sliding friction torque components of DGBBs: Spinning friction, differential sliding friction due to the ball rotation, and differential sliding friction due to the ball orbital motion. An efficient and accurate computational method is proposed for the individual sliding friction sources, based on pure rolling lines in the elliptical contact area between the balls and races. The proposed method applies an updating algorithm, for estimating more accurate information about the pure rolling lines. The proposed method was validated in terms of comparison with other methods, and with the empirical formulae provided by a bearing manufacturer. Simulations were also conducted to investigate the impacts of important parameters on the sliding friction torque in DGBBs.