液压技术在带钢回转台上的应用

莱钢带钢回转台采用普通换向阀,其控制液压冲击大,节流阀速度调节能力差;叶片式马达抗冲击力弱,经常出现叶片断裂;密封性差内泻量大,致使负载能差。为此,采用比例技术和螺旋摆动液压缸等措施,对回转台进行了改进。比例方向阀控制速度方便灵活,液压冲击小;螺旋摆动缸输出转矩大,抗震性能优越,效率高;整体结构简单,提高了稳定性。     

双摆动套筒快速换辊车的试验研究

双摆动套筒快速换辊车,较适用于已投产但需增设快速换辊设备的轧机技术改造上。通过试验研究,证实了双摆动套筒快速换辊车使用可靠、换辊时间较短,还基本找到了防止轴承座转动的措施、套筒内衬垫的合理外形,走行采用液压马达传动的特点,从而为进一步研制双摆动套筒快速换辊车提供了必要的依据。     

环形炉炉底机械传动装置设计分析

比较了环形炉炉底机械传动装置的机械传动和液压传动的两种结构特点,分析了液压马达的比例阀调速、多流液压同步马达控制多台液压马达以实现其同步运转;同时介绍了销齿传动设计,提出针对不同的环形炉应采用的炉底机械传动装置.     

对同步马达多缸同步液压控制系统的分析及改进

以同步马达为同步控制元件的多缸同步液压控制系统广泛应用于冶金等各行业。本文以转炉烟罩同步马达升降液压控制系统为例,分析传统同步马达多缸同步液压控制系统的工作原理和特点,针对其存在的问题提出了一种带纠偏功能的同步马达多缸同步液压控制系统,已将其实际应用于生产中,并取得了良好的效果。     

锻造操作机钳杆机构液压系统节能分析

根据锻造操作机钳杆机构液压系统的特点,研究了钳杆机构旋转液压系统中位置闭环控制与流量补偿位置闭环控制的节能特性,分析了系统参数对钳杆转角响应带来的影响。研究结果表明无论是在马达的加速还是减速阶段,流量反馈位置控制系统的能量利用率都明显高于位置反馈控制系统,研究结果为锻造操作机液压系统的节能设计提供了基础,具有实践应用意义。     

某高线轧机液压马达驱动系统故障分析

针对某高线轧机液压马达驱动系统在运行试验时出现的马达油封损坏现象进行了分析,通过现场调试、改进,以及马达运行数据计算的结果得出,液压控制原理、马达的选型、回油管径的选择及铺设,都会影响到整个液压马达系统的使用性能。给出了设计注意事项和解决办法。     

远控近采水枪

远控近采水枪,用于砂矿开采,采用液压摆动马达及油缸进行驱动和液压控制,该水枪外形紧凑移动方便,可远距离操作而使水枪在距工作面较近的距离内开采,能大幅度地提高工作效率,节约矿山用水,该水枪可有效地减轻劳动强度,改善工作环境,实现安全生产。     

京唐2号高炉上料主胶带机液压马达传动技术

对京唐2号高炉上料主胶带机液压马达传动技术的开发和应用进行了简要总结。针对传统交流电机传动方式的不足,结合2号高炉的特点,开发了液压马达传动技术。液压马达传动技术的成功应用及多项相关应用技术创新,大幅提高了设备可靠度,降低高炉亏尺率,使高炉装料制度灵活可调,设备运行免维护,噪音小,无高压配电设施,有利于安全生产和节能降耗。     

炸药车的摆线式液压马达

PP炸药车引进美国埃利克(ireco)化学工业公司技术,车上多处液压执行机构采用了摆式液压马达。文中结合对此类液压马达的技术消化,介绍了摆线式马达的工作原理、摆线参数、结构特点、配流形式,并提出了保养维修工作的技术要点和注意事项。     

转炉新式驱动方案的分析与探讨

本文对转炉采用液压马达驱动进行了试验设计研究，通过设计计算，第一次得出转炉采用液压马达驱动是可行的，而且这种驱动方案比相同容量的电机驱动优点突出，最后给出了液压马达驱动系统的结构设计     

环形套筒窑旋转布料器液压系统和控制程序的改进

环形套筒石灰窑旋转布料器存在易堵转和过限位的问题,分析认为,主要原因是液压回路中液压元件参数不匹配而使回路的静态特性和功率特性差以及旋转布料器的控制方式设计不合理。为此,在液压回路上增加了1台同型号的液压马达与原有马达并联共同驱动旋转布料器,并采取不固定受料点的控制方式,减小旋转布料器负载的变化幅度,弱化回路刚性差对设备性能的影响。改进后旋转布料器故障时间由原来的每年166h减为0,使用时间由2年提高到6年以上。     

加料机回转平台液压调速及油温控制系统设计

地面加料机回转平台驱动马达没有转速调节功能,操作时极易失控,采用液压比例阀调节液压马达的流量,实现了对回转台的平稳控制;针对设备工作环境恶劣,液压油温经常过高的问题,采用高温油冷却机对高温工作环境下的加料机液压油进行强制冷却,有效地解决了这一问题．增强了设备对恶劣工作环境的适应能力。     

Hemifacial hypoplasia and hypomelanosis of Ito

Seventy patients with adolescent idiopathic right thoracic scoliosis had full assessment of their pulmonary function using a computerised pulmonary function system. Their mean age at evaluation was 13.8 years. The following measurements were obtained from anteroposterior and lateral standing and antero-posterior supine bending radiographs: lateral curvature, vertebral rotation, kyphosis, maximum sterno-vertebral distance and apical rib-vertebral angles. Using the above measurements, the flexibility of curve, vertebral rotation and rib-vertebral angle asymmetry were calculated. Patients were classified into three groups on the basis of their predicted vital capacity, to determine whether radiological features of deformity can help identify patients with compromised pulmonary function. The mean Cobb angle and vertebral rotation for the 70 patients were 50 degrees (range 35-100 degrees) and 22 degrees (range 1-44 degrees) respectively. The mean flexibility of curve and vertebral rotation were 52% and 49% respectively. Mean thoracic kyphosis was 25 degrees, ranging from -7 to 55 degrees. Of the patients with Cobb angle less than 90 degrees, 71% had vital capacity less than 80% of predicted values, and of these, 18% had marked compromise of vital capacity (less than 60% of predicted values). Mean values of Cobb angle, vertebral rotational flexibility, kyphosis, rib-vertebral angle asymmetry (in standing as well as supine bending radiographs) differed significantly between patients with more than 80% of predicted vital capacity and those with 60% or less of predicted values. Radiological features indicative of better pulmonary function were: rotational flexibility exceeding 55%, rib-vertebral angle asymmetry (standing) less than 25 degrees and kyphosis greater than 15 degrees. Two deformity parameters--that give a better prediction of pulmonary function than the widely used Cobb angle, vertebral rotational flexibility and rib-vertebral angle asymmetry--were identified in this study.     

斜轧扩管机的工艺特征

斜轧扩管机是无缝钢管生产系统中比较重要的一种机型,主要适用于生产大口径中薄壁钢管。采用空间解析和有限元模拟的结果,对斜轧扩管机的送进角、主变形和附加变形进行了分析,可为同类机组的品种开发、工艺优化、设备改造和设备设计提供依据。分析结果表明:①斜轧扩管机的轧辊调整与普通斜轧管机不同,但与普通斜轧管机一样具有送进角;②辗轧角和轧辊平移是斜轧扩管机形成送进角的必要条件,辗轧角越大、轧辊平移距离越大,则送进角越大;③斜轧扩管机的减壁变形主要转化为扩径变形,纵向变形很小;④斜轧扩管机的附加变形远小于普通二辊斜轧的附加变形,而且扭转变形很小。     

筒体中心线的倾斜对回转窑轴向运动的影响

论述了“割线法”求筒体中心线的倾斜角，并分析了倾斜角对回转窑轴向运动的影响。使回转窑在线测量或监测方法能够运用于回转窑的轴向运动分析。     

液压泥炮旋转机构的运动特性分析

采用矢量方程解析法对液压泥炮旋转机构建立数学模型,全面求解了炮嘴轨迹、转臂旋转角速度、炮嘴速度、活塞杆行程与转臂转角关系等关键参数。对旋转机构的设计、优化及驱动油缸液压系统控制的设计具有较高的参考价值。     

直接还原转底炉转速控制系统设计

直接还原转底炉因其工艺独特,能够有效处理冶金污泥粉尘、红土镍矿、复杂难选矿等物料,日益受到治金行业的关注。直接还原转底炉工艺控制最核心部分之一就是还原物料的周期,即必须按照生产工艺的要求的时间完成一个旋转周期,转速控制精度要求高,误差小。文章介绍了直接还原转底炉液压系统原理、控制系统组成、程序设计。     

螺旋旋转式混料机在铁合金生产中的应用

介绍了螺旋旋转式混料机在铁合金生产中的应用。螺旋旋转式混料机是在回转窑的基础上,根据搅拌机原理进行改造的混料机。即在混料机的筒体内,加装特殊形状的螺旋板,使混料机进、出物料口合一,能够在正向旋转时加混料,反向旋转时自动出料,以达到混合物料的目的。该螺旋旋转式混料机的应用,可减少传统混料系统的倒运及加、出料速度,维护维修方便,易加装除尘器,满足环保要求。可提高生产效率,降低生产成本。     

The stiffness of lumbar spinal motion segments with a high-intensity zone in the anulus fibrosus

STUDY DESIGN: Biomechanical and anatomic study of human cadaveric spinal motion segments. OBJECTIVES: To measure the stiffness of spinal motion segments by disc type and by load type (flexion, extension, axial rotation, or lateral bending). To compare stiffness in motion segments with and without a high-intensity zone or radial tear in the anulus fibrosus. SUMMARY OF BACKGROUND DATA: The high-intensity zone, that is a linear zone of high-intensity on T2-weighted magnetic resonance images corresponding to a radial tear in the anulus fibrosus, is a marker for a painful disc at discography. The high-intensity zone is hypothetically associated with diminished stiffness of the motion segment. METHODS: Human cadaveric lumbar spinal motion segments with normal disc morphology or a high-intensity zone of the anulus fibrosus were selected on the basis of magnetic resonance imaging. The motion segments were subjected to incremental flexion, extension, rotation, and lateral bending torques. Rotation was measured with a kinematic system. Torque-rotation curves and stiffness were calculated for each motion segment and for each torque. The motion segments were sectioned on a cryomicrotome to verify the disc morphology as normal or as that of a radial tear. RESULTS: In four motion segments with normal discs, stiffness was greater in axial rotation (8.4 Nm/degree) than in lateral bending (2.3 Nm/degree), flexion (1.8 Nm/degree), or extension (2.6 Nm/degree). In 16 motion segments with a high-intensity zone, stiffness was 2.4 Nm/degree in axial rotation, and less severely reduced in lateral bending, flexion, and extension. Stiffness in motion segments with a high-intensity zone was significantly less with smaller than with larger axial rotation loads. CONCLUSIONS: The presence of a high-intensity zone in the intervertebral disc is associated with reduced stiffness of motion segments. The reduction is greater in axial rotation than in other torques. The reduction is more in smaller than in larger axial torques.     

轧制力参数对斜轧穿孔孔型的影响

为了进行斜轧穿孔模型化研究,分析了二辊斜轧穿孔轧制力对轧辊开度、变形参数和穿孔毛管壁厚均匀性的影响以及顶头轴向力对变形参数和毛管壁厚均匀性的影响。结果表明：轧制力引起的静态轧辊辗轧角变化可以忽略,而轧制力对毛管壁厚的影响很显著。顶头轴向力引起的顶头位置变化对轧件壁厚及其均匀性的影响是值得重视的。