无键皮带轮

机械传动中皮带轮大多采取过渡配合键联接或过盈配合,但在拆装过程中比较麻烦。所以,我设计了一种易装拆,对电机轴无损害的装配结构,适合需经常检修、拆换加油的电机。皮带轮与轴的装配形式如图1所示,装配时锥孔压缩锥套,使轮毂,锥套,轴之间相对产生过盈装配,锥套和轮毂的锥度采用1:20,锥套长度等于轮毂的厚度。锥度套大端直径等于锥孔大端直径加上所需过盈量的1.5～2倍。从手册中查得不加紧固件可传递扭矩的装配量:(H7)/(s7);(s7)/(h6);(H80/(u8)。     

快速装卸皮带轮

现将快速装卸皮带轮的结构作一介绍。皮带轮与轴的装配形式如图所示。锥套和轮毂的锥度为1:25,锥套大端直径略大于锥孔大端直径0.5～1毫米,锥套孔尺寸比轴颈尺寸大0.1毫米左右,锥套做成单开口式。皮带轮在装配时旋转顶丝3,当顶丝到达锥套上之半丝扣底部时,由于继续旋转顶丝3,在带轮上的半丝扣的作用下,使皮带轮与锥孔产生轴向位移,并通过内锥面使开口锥套束紧,从而实现过盈配合,以传递扭矩。     

大尺寸高精度锥轴工件精加工过程检测及补偿方法研究

针对大尺寸高精度锥轴类工件加工成本高、一次尺寸合格率低,传统检具需反复装卡工件,不能用于加工过程的检测等问题,对高精度锥轴类工件锥度的精加工过程检具及其补偿方法进行了研究。以某大型矿机锥度主轴及用于加工的大型卧式车床为研究对象,根据锥度的计算原理,建立了用于表征锥轴工件锥度和圆跳动的量化分析模型。在此基础上,综合考虑锥度主轴精加工工艺系统、精加工过程测量和补偿方法,结合卧式车床的结构特点,设计了可用于精加工过程中锥度和圆跳动尺寸测量的专用检具,给出了相应的过程测量和补偿方法,并将其应用于某大型矿机主轴的精加工过程。研究表明:该装置可方便地应用于大型锥轴类工件的精加工过程,可准确测量出精加工过程的锥度和圆跳动偏差,并直观地显现出补偿量大小及位置,有效提高了大型锥轴类工件精加工尺寸合格率。从而为大尺寸锥轴类工件的批量加工提供了技术保障。     

大直径易损件锥孔的加工

一些大直径回转体的装配孔,往往是带锥度的,而锥孔的加工比直孔的加工要困难得多。首先是锥孔的精确尺寸不易测量,特别是孔口处加了倒角;其次,即使能测量,小拖板的角度也未必能准确地调到这一角度,对于大零件,就不可能在加工锥孔的过程中,用轴来检测锥度情况（多数情况下轴在设备上不     

高精度弹性涨开心轴

为满足生产要求,我们设计了一种高精度弹性涨开心轴,其结构如图。心轴两端顶住中心孔,用鸡心夹作传动。转动压紧螺母,推动锥套(弹性锥套锥度部分开有三条槽,均布),在锥度的导向下,使弹性套在两端锥体的作用下自动涨开,达到涨紧工件的目的。松开螺母,在压力弹簧作用下使锥套移动脱开,使弹性套复位,松开工件。要求工件孔粗糙度低于1.6,孔的不圆度在0.01mm范围内,主轴顶尖与尾架顶针间的加工件,其锥度小于0.01mm。在上述条件下精车外圆或磨外圆,其同轴度误差小于0.005mm,精车端面可使端面对孔轴线的垂直度误差小于0.005mm。该心轴制造简单,由于采用弹性锥套,消除了锥套与心肘间的间隙误差,使其成为无间隙配合。由于     

如何加工大直径易损件上的锥孔

在设备维修过程中 ,对于一些老设备上的易损件 ,在配件无处购置的情况下 ,要想继续使用该设备 ,用户必须自己解决加工问题。而一些大直径回转体的装配孔 ,往往是带锥度的 ,而锥孔的加工比直孔的加工要困难得多。首先是锥孔的精确尺寸不易测量得到 ,特别是孔口处加了倒角的时候 ;其次 ,即使能测量得到 ,小拖板的角度也未必能准确地调到这一角度。而且多数情况下轴在设备上不卸下来 ,在加工锥孔的过程中 ,无法用轴来检测锥度情况。这时 ,可按以下步骤来加工锥孔 ,能保证加工出来的锥孔满足装配要求。(1)预先准备好一根心轴 (事先已按锥孔的大…     

摇臂钻床加装铣刀的装置

在摇臂钻床上锪窝或校正钻斜了的偏孔时,若能将铣刀装夹在钻床上有时会减少许多麻烦。但标准铣刀不能直接装人摇臂钻床主轴,因为铣刀是靠其柄部内螺纹通过拉杆将其拉紧,使铣刀柄部莫氏圆锥面与机床主轴锥孔配合来完成传递扭矩和切削任务的。为此,设计了如图所示的装置,现介绍给大家。 舌尾锥体１的柄部是根据机床主轴莫氏圆锥设计的,在前端车出螺纹,开一对称的键槽口,内部做成圆锥孔,锥体５的外圆面同舌尾锥体１的锥孔相配合,而内锥孔按５号莫氏锥度制作。５号莫氏锥度铣刀可直接装人,若要装人４号或３号铣刀则可使用锥套４,锥…     

拆卸普通向心轴承的方法

在大量生产轴类零件时,装夹都会用到活动顶针。活动顶针中顶尖和轴承又易损坏。在更换过程中,经常会遇到顶尖拆下后,向心轴承留在顶针套内,现介绍一种拆卸普通向心轴承的方法。 如图:内胀轴内锥一般为30°左右,并且四等分剖开。内胀锥体的外锥度比内胀轴的内锥大1°～2°。如图     

使用正弦规检测锥度

<正>正弦规检测锥度的工作原理是:当正弦规垫好块规的精确高度后,正弦规工作面与平板夹角理论上等于锥角α。如果被测锥体的锥度值α精确无误,则锥体的上母线与平板平行。这时用千分表检     

测量锥孔用新型锥度量规

使用传统的锥度量规测量锥孔的锥度时主要采用涂色对研法,该方法测量效率低,可靠性差,量规易磨损,且测量结果评定困难,无法得到准确的锥度值。本文介绍的新型锥度量规则可较好克服上述缺点。１－结构原理传统锥度量规的测量原理是在锥体的一定轴向长度内测量其径向差值。新型锥度量规的测量原理则是首先确定标准锥度的径向差值,然后测量对应的轴向长度。图１为新型锥度量规的结构示意图。量规由件１～３三个零件组成。直径Ｄ用于控制锥孔大头尺寸,其公差可通过刻线或台阶来保证。长度ｌ约为锥体长度的１／２,长度ｌ１约为锥体长度的…     

直母线锥盘金属带式无级变速器带的轴向偏移分析

分析了直母线锥盘金属带式无级变速器带的轴向偏移。阐述了传统控制方法的弊端：传统曲母线锥盘与金属片产生角点接触，在传动比i=1附近传动比变化不连续；在传动比i=1时，预置带的轴向偏移量只能使带的最大偏移量减小到未调整时的50％～60％。提出复合母线锥盘，锥盘母线与金属片侧边共轭，既完全消除了金属带的轴向偏移，又与直母线锥盘具有相同的接触强度，提高了无级变速器的传动能力，扩大了无级变速器的应用范围。     

The complexity of the visual cells and visual pathways of the sturgeon

The visual cells in the retinae of the sturgeon were studied by scanning electron microscopy and transmission electron microscopy. Our investigations revealed the presence of rods, two types of single cones, one type of double cone (two nonidentical cone components adhered together), and one type of twin cone (two identical cone components adhered together). In some of the cones, large glycogen bodies were present in the inner segments and all cones contained oil droplets. Such cone morphology was very similar to that described in the retinae of higher vertebrates, for example the chicken. DiI tracing of retinofugal pathways following uniocular injection demonstrated their bilateral localization and extensive termination in the diencephalon and mesencephalon of both sides. Fibers also crossed over from one side to another through commissures, including the posterior commissure. The complexity of the pathway surpassed that of the teleosts and further indicated the evolutionary importance of this fish.     

Thickness improvement in single point incremental forming deduced by sequential limit analysis

Multistage forming is one of the most practical solutions to avoid severe thinning in single point incremental forming (SPIF). A successful implementation of multistage SPIF is strongly dependent on an appropriate deformation path. In this paper, firstly, a simplified modeling technique is proposed using sequential limit analysis. It is shown that sequential limit analysis can predict the thickness distribution faster than an equivalent model in a commercial finite element modeling code like Abaqus can. The reliability of the model is assessed by comparing experimental and simulated results for single-stage and multistage SPIF cones. This model is utilized to study the effect of various deformation paths on the thickness distribution. As a result, a new multistage strategy is designed and implemented to form a 70° wall angle cone in three stages. The thickness distribution of the cone is improved significantly compared to cones formed by a single-stage and a conventional three-stage strategy. Besides this improvement, the new multistage SPIF can be carried out in much less time.     

Photoreceptor cells in the Xenopus retina

This review summarizes our present state of knowledge about spectrally different photoreceptor cell types in the Xenopus retina. The classification of the photoreceptors was based on morphology, combined with immunolabelling with various anti-visual pigment antibodies and other molecular probes on semithin sections and retinal wholemounts. The majority of photoreceptors is represented by rods. Altogether 97-98% of the total rod population consists of the principal ("red") rods that are selectively labeled by N-terminal specific anti-bovine rhodopsin monoclonal antibodies (mAbs) and are maximally sensitive to green light. The other, rare, blue-sensitive rod type ("green rod") is thinner, not stained by these antibodies but binds C-terminal specific anti-rhodopsin mAbs. The major representatives of the cones are red-sensitive and consist of a morphologically heterogeneous group comprising both (principal and accessory) members of double cones, as well as large single cones. Outer segments in this group are selectively labeled by mAb COS-1, specific to the L/M group of cone visual pigments. Another, relatively rare cone type is similar in size, but slightly smaller than the large single cone and is not labeled by mAb COS-1. This cone type is assumed to have a blue-sensitive cone visual pigment. The third, least abundant, and immunocytochemically distinct cone type is a small single (miniature) cone, which binds mAb OS-2 relatively strongly, and anti-rhodopsin mAbs 4B4 and 1D4 weakly. By exclusion, this small single cone may be identical with the UV-sensitive cone. Further studies are needed, however, to identify the color sensitivity of the latter two cone types.     

惯性圆锥破碎机多体动力学分析及试验验证

惯性圆锥破碎机存在整机振幅大且能耗高等问题，制约了其在工业领域的进一步发展，其多体动力学求解可以为明确各主要动力学参数与整机振幅和能耗的关系提供理论计算方法。采用绝对坐标法建模，将动锥的纯滚动约束等效为完整和线性非完整约束，得到了含一阶线性非完整约束的微分代数方程组,提出了基于隐式Runge-Kutta积分变步长的LU状态空间法。在稳定工况下，对定锥各测量点动态响应的仿真结果和工业现场试验结果进行对比分析，验证了模型和数值算法的有效性。计算结果表明：驱动转速、定锥质量、阻尼系数和动锥质量对振幅的影响较大，刚度系数对振幅几乎没有影响；增加定锥的质量可以有效降低单位能耗；在一定范围内，增加阻尼系数会造成阻尼耗散增大，使单位能耗升高。     

光锥在光电探测仪器中的应用和设计方法

光锥可以弥补场镜、光纤在光电探测仪器中光线传输汇聚的弊端,光锥传输光线不但损失小,而且可以把光阑后面的光线根据需求分开传输。通过光锥的应用,使光电探测器的灵敏度大幅增强。叙述了光锥的传输特性和设计方法。     

Photoreceptor classes and transmission at the photoreceptor synapse in the retina of the clawed frog, Xenopus laevis

The photoreceptor population in Xenopus consists of a green-sensitive rod (lambda(max) = 523 nm), a blue-sensitive rod (lambda(max) = 445 nm) and three classes of cone. The largest cone is red-sensitive (lambda(max) = 611 nm). The intermediate cone is presumed to be blue-sensitive based on physiological criteria, whereas the miniature cone may be UV-sensitive. Horizontal cells (HC) are of two sorts: axon-bearing and axonless. The axon-bearing HC is of the luminosity type and probably contacts all types of photoreceptor. The axonless HC is of the chromaticity type and contacts only intermediate (blue) cones and at least one type of rod. During development dendrites of HCs and bipolar neurons penetrate photoreceptor bases. A progressive maturation of HC and bipolar synapses with rods and cones occurs between tadpoles stages 37/8 and 46. Neighboring rods and cones are joined by gap junctions. During this same period, the outer segments are laid down and photopigments synthesized. A linear relation was found between the quantum capturing ability of the rod and its absolute threshold. Mature rods of the Xenopus retina release glutamate in a calcium-dependent manner. Glutamate release was found to be a linear function of calcium influx through L-type calcium channels. Both types of HC possess ionotropic glutamate receptors of the AMPA subtype.     

基于LabVIEW的角速度、角加速度测试仪

介绍了利用LabVIEW开发的角速度角加速度测试仪，详细分析了此虚拟测试仪器的硬件、软件的实现原理。该虚拟仪器能够与实验室里传统的JC-83型角速度角加速度测定仪的部分硬件配合使用，成为新型的机械原理课程教学实验仪器。通过对四杆机构进行了实际的角速度角加速度测试实验，证明了该虚拟仪器有传统仪器无法比拟的优势，能使传统仪器具有新的利用价值。该虚拟仪器灵活性好，能够根据需要移植应用到其他的测试场合。     

光学计量仪器中V型导轨副双锥滚子的研究

简要说明了在光学计量仪器中,现在工作台应用滚动V型直线导轨副时,面临大负荷高精度的困难。提出在滚动V型直线导轨副中,改变现有滚动件的形式,采用双锥滚子作为滚动件的新思想,从多方面探讨其可行性及其面临的实际问题。同时,从工艺的立场探讨其冷加工方法和装配要点。该技术从设计角度和工艺技术角度均可实现。该技术既可解决光学计量仪器中工作台在大负荷、运动保持高精度的情况,又可应用于机床行业或其它装备制造业。     

刚散耦合振动圆锥破碎机动力学分析

将振动圆锥破碎机简化为六自由度运动的物理模型,物料层采用分段线性接触力模型来表示。应用Lagrange方程,对振动圆锥破碎机进行了建模。通过Matlab采用Runge-Kutta法对振动微分方程组进行数值计算仿真,研究了不同激振频率下系统的动力学性能。研究结果表明,物料层的作用是系统非线性的根本来源,物料层的非线性导致系统从单一频率的简谐运动变为复杂运动,为振动圆锥破碎机的参数选择提供了依据。