谐波齿轮间隙装配下柔轮齿圈的力学特性及轮齿定位研究

现有理论认为变形后柔轮齿圈中性线为整圈贴合凸轮轮廓的等距线，未考虑配合间隙和中面伸长的影响。为揭示配合间隙装配状态下柔轮的力学特性和齿圈变形后的轮齿定位，以椭圆凸轮波发生器为例，考虑柔轮内壁与波发生器外圈间隙和柔性轴承游隙引起的配合间隙及齿圈中面伸长，建立了柔轮齿圈变形的接触力学模型；引入变形后包角为未知参数，依据包角内用椭圆等距线表示的齿圈中线的曲率及力平衡条件确定齿圈内力；根据短轴处的位移条件和包角处的曲率条件及弧长关系，运用能量法迭代计算了包角、非接触区的大小及齿圈的内力和变形。以有限元模型结果为参照，对比验证了理论结果和轮齿定位偏差。理论分析和数值模拟均表明，受中面伸长的影响，零间隙配合的实际包角远小于90°，整圈贴合凸轮并不符合实际；降低配合间隙可有效增大轴承承载区，降低柔性轴承的径向负载和磨损；考虑包角和周向伸长，可以获得更准确的轮齿定位。研究为谐波齿轮的结构设计和啮合分析奠定了更准确的基础

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements