精密蜗杆磨床砂轮廓形修整补偿的误差分析

磨床工艺系统原始几何误差的存在及随工况改变,造成砂轮廓形修整补偿量也在随时发生变化,因此需要对砂轮廓形进行实时重新设计来补偿安装角、中心距的变化影响,才能从理论上保证螺旋型面的精确成形磨削。建立ZN型蜗杆的数学模型,推导存在安装角误差条件下的齿面方程。探讨了存在安装角误差情况下的齿形误差对砂轮廓形修整补偿的影响规律,并以法向齿廓蜗杆(ZN)的精密成形磨削作为实例进行了验证

Comparison and analysis on stress and strain of overrunning clutch

建立了典型的普通滚珠式超越离合器、楔块式超越离合器与多滚柱式超越离合器工作时应力应变状态模型,通过对三种超越离合器进行自锁失效分析,利用模拟仿真方法研究并比较了应力应变的变化对三种超越离合器的使用寿命的影响。In this paper, stress and strain model of ordinary overrunning roller clutch, wedge type overrunning clutch and overrunning clutch with more rollers are founded.Through analysis on self-locking failure,comparison of the effects that stress and strain change brings to the three kinds of overrunning roller clutch on work life are made by way of simulation

Method of error compensation for precise grinding the helical rotor tooth profile

针对成形法精密磨削加工螺杆转子螺旋面的问题,研究了螺杆转子加工过程中由工艺系统误差产生的齿廓加工误差的补偿方法。提出了一种基于首件转子磨削后的齿; 廓测量误差,进行预处理再修整砂轮的新算法。使用处理后的补偿数据对砂轮修整后,加工误差明显减小与收敛,大大提高了磨削转子的齿廓制造精度。Aiming at the process of the machining screw rotor helical surface by; forming precision grinding, the compensation method of tooth profile; error caused by the process system error in the process of screw rotor; machining is researched. A new pretreatment and refinish grinding wheel; algorithm is proposed which based on the measurement error of the tooth; profile after the first rotor grinding. After the grinding wheel was; dressed base on the compensated data, machining error is obviously; reduced and convergence, the machining precision of root is improved; obviously.陕西省地方重大资助项

螺杆转子成形磨削用砂轮廓形的包络-像素设计方法

针对双螺杆压缩机核心部件螺杆转子的高效高精制造问题,提出一种基于包络-像素法的螺杆转子成形磨削用砂轮廓形的设计方法,能够在图形空间高效完成螺杆转子成形磨削用砂轮廓形的设计。该方法结合计算机图形学与啮合原理相关理论,建立了螺杆转子与砂轮之间包络运动形成的扫掠面模型,基于Bresenham算法用指定的颜色点亮最佳逼近像素点,通过边界跟踪方法依次分段提取边界像素点,得到精准的成形砂轮廓形数据。通过与传统解析包络法的对比以及实际磨削试验,结果表明,包络-像素法与解析包络法生成的成形砂轮廓形偏差在±0.003mm,加工转子误差在±0.01mm,可以满足实际工业应用。另外,包络-像素法可避免传统啮合运动共轭曲面的接触线计算中存在求解非线性方程复杂、异常解和人工干预等不足,为计算机图形学技术在螺旋面刀具廓形设计应用提供新思路,亦适用于齿轮、蜗杆、铣刀等类似共轭产品的设计。工信部智能制造综合标准化与新模式应用项目(工信部装函[2018]265号)中国博士后科学基金资助项目(2019M652256

螺杆转子成形磨削用砂轮廓形的包络-像素设计方法

针对双螺杆压缩机核心部件螺杆转子的高效高精制造问题，本文提出一种基于包络-像素法的螺杆转子成形磨削用砂轮廓形的设计方法，能够在图形空间高效完成螺杆转子成形磨削用砂轮廓形的设计。该方法结合计算机图形学与啮合原理相关理论，建立了螺杆转子与砂轮之间包络运动形成的扫掠面模型，基于Bresenham算法用指定的颜色点亮最佳逼近像素点，通过边界跟踪方法依次分段提取边界像素点，得到精准的成形砂轮廓形数据。通过与传统解析包络法的对比以及实际磨削试验，结果表明，包络-像素法与解析包络法生成的成形砂轮廓形偏差在±0.003 mm，加工转子误差在±0.01 mm，可以满足实际工业应用。另外，包络-像素法可避免传统啮合运动共轭曲面的接触线计算中存在求解非线性方程复杂、异常解和人工干预等不足，为计算机图形学技术在螺旋面刀具廓形设计应用提供新思路，亦适用于齿轮、蜗杆、铣刀等类似共轭产品的设计。工信部智能制造综合标准化与新模式应用项目（工信部装函[2018]265号）中国博士后科学基金资助项目（2019M652256

Simulation of surface topography considering process-machine interaction in grinding

磨削加工方法是保证加工表面质量的重要手段,机床结构与磨削过程之间存在的交互作用会对工件表面质量产生不利影响。以砂轮端面磨削加工过程为研究对象,在研究磨削工件表面形貌仿真方法的基础上,深入分析了机床结构与磨削过程之间交互作用对工件表面形貌的影响。首先基于砂轮表层磨粒的随机分布特性建立了虚拟砂轮形貌,然后通过对磨削过程中砂轮磨粒与工件几何干涉作用的分析,建立了磨粒运动轨迹方程和工件表面形貌方程。考虑砂轮变形对磨削过程的反向作用,建立了主轴-砂轮结构与磨削过程间的交互模型,采用耦合仿真的方法对机床-磨削交互过程进行了仿真,并考虑磨削过程中的交互作用提出了一种新的磨削工件表面形貌仿真模型,实验结果验证了所给算法的正确性和有效性,该方法为进一步优化磨削工艺参数提供了依据。Grinding is an important means to guarantee the quality of the machined surface,however,the interaction between machine and grinding process reduces surface quality. Focusing on face grinding,the influence of process-machine interaction on ground surface was analyzed based on the investigation of surface topography simulation. A visual wheel topology was simulated based on the random nature of grains located on the wheel surface. The grain trajectory equation and workpiece topography equation were established based on the analyses of interference between grains and workpiece. The interaction between grinding process and spindle-wheel was modeled considering the inverse influence of wheel deformation on process and simulated by adopting a coupling simulation method. Taking the processmachine interaction into account,a novel simulation model for surface topography of the grinding process was proposed.Grinding test verifies the accuracy and effectiveness of the given algorithm. The method can be further used to optimize the grinding process parameters.福建省高校产学合作科技重大项目“高效、高精度可转位刀片周边刃磨关键技术研究”(2014H6025

切削力系数辨识的贝叶斯推断方法

快速标定斜角切削力系数的方法在切削力建模中得到了广泛应用,但该方法忽略了系数辨识过程中的不确定性因素。针对此问题,提出了一种基于贝叶斯推断的切削力系数辨识方法。推导了镶齿面铣刀铣削力解析模型,给出了快速标定斜角切削力系数的线性回归方法。通过马尔科夫链蒙特卡罗方法从切削力系数的后验分布中生成样本,然后基于贝叶斯推断方法评价切削力系数的变化。在给定的实验条件下,分别用线性回归方法和贝叶斯推断方法进行切削力系数辨识,将计算得到的铣削力与实验铣削力值进行对比,结果表明贝叶斯推断方法具有更高的预测精度

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors