The term“over-skidding”indicates that the cage rotational speed ratio exceeds the theoretical value as ball purely rolls on the raceway.Different from the skidding phenomenon that occurs in low-load and high-speed b...The term“over-skidding”indicates that the cage rotational speed ratio exceeds the theoretical value as ball purely rolls on the raceway.Different from the skidding phenomenon that occurs in low-load and high-speed bearing,over-skidding usually occurs in large-size angular contact bearings,and it is still difficult to suppress under high load conditions.The main forms of damage to the raceway by over-skidding are spinning and gyro slip.To further explore the vibration characteristics and thermal effects of this phenomenon,a set of over-skidding tests of an angular contact bearing with a bore diameter of 220 mm were conducted on an industrial-size test bench.Through the experiment,the influence of axial load,rotational speed,and lubrication conditions on the occurrence of over-skidding were determined.Based on a previous dynamics model,the heat generation and thermal network models were integrated in the present study to predict the over-skidding and its thermal behavior.The model was validated in terms of the measured degree of over-skidding and temperature rise.The results showed that the degree of over-skidding reaches up to 12%of the theoretical value,and the friction power loss of the ball-pocket accounts for 30%of the total power loss.The analysis of the vibration signal showed a strong correlation between the bearing vibration characteristics and over-skidding behavior,thereby providing a way to indirectly measure the degree of over-skidding.展开更多
基金supported in part by a scholarship from the China Scholarship Council(CSC)(No.201806880007)the National Natural Science Foundation of China(No.11872222)the State Key Laboratory of Tribology(No.SKLT2021D11)。
文摘The term“over-skidding”indicates that the cage rotational speed ratio exceeds the theoretical value as ball purely rolls on the raceway.Different from the skidding phenomenon that occurs in low-load and high-speed bearing,over-skidding usually occurs in large-size angular contact bearings,and it is still difficult to suppress under high load conditions.The main forms of damage to the raceway by over-skidding are spinning and gyro slip.To further explore the vibration characteristics and thermal effects of this phenomenon,a set of over-skidding tests of an angular contact bearing with a bore diameter of 220 mm were conducted on an industrial-size test bench.Through the experiment,the influence of axial load,rotational speed,and lubrication conditions on the occurrence of over-skidding were determined.Based on a previous dynamics model,the heat generation and thermal network models were integrated in the present study to predict the over-skidding and its thermal behavior.The model was validated in terms of the measured degree of over-skidding and temperature rise.The results showed that the degree of over-skidding reaches up to 12%of the theoretical value,and the friction power loss of the ball-pocket accounts for 30%of the total power loss.The analysis of the vibration signal showed a strong correlation between the bearing vibration characteristics and over-skidding behavior,thereby providing a way to indirectly measure the degree of over-skidding.
文摘为探究集材绞盘机噪声特性及环境影响,基于JS3-2、武夷781及JSD3-2绞盘机声级实测数据,进行Arc GIS可视化分析、模型处理、均值统计和环境评价。结果表明:绞盘机工作噪声大小及空间分布特性与绞盘机型号和数量基本无关,而距离绞盘机越近,噪声值越大,噪声等值线越密集,噪声随距离变化波动程度小;距离绞盘机5 m以外,绞盘机噪声等值线分布较均匀,噪声变化趋于稳定;电动绞盘机振动噪声比柴油绞盘机噪声大2-6 d B;多台绞盘机同时工作的噪声大小与分布,基本等同于其中产生最大噪声的单台绞盘机的情况,环境影响不存在叠加效应;绞盘机工作噪声环境均达重度污染,会使绞盘机司机感觉吵闹,有损工人听觉与视觉神经并会干扰集材作业。
