六辊钢管矫直机液压系统设计说明书(编辑修改稿)

六辊钢管矫直机液压系统设计说明书(编辑修改稿)内容摘要：

液压油密度 (kg/m3) λ 沿程阻力系数 ξ 局部阻力系数 △ p3=△ pn(Q/Qn)^2 式中 Qn阀的额定流量 (m3/s) Q通过阀的实际流量 (m3/s) △ pn阀的额定压力损失 (Pa), 矫直 机执行部件有主缸和 平衡缸，夹送辊摆动缸，辊道升降缸，换辊马达，下中辊高度调整液压马达 ，供油管子管径如下 名称 D1 D2 D3 D4 D5 D6 D7 内径 60.3 25.4 15.9 8 19 28.6 19 最后根据标准 软管 取值如下 液压油选用 LHL32 液 压 油 ， 15 ℃时该油液的运动粘度scmcst / 2 ,油液密度 3/920 mkg。 （ 1） 快开 缸各工况时的压力损失验算 1） 快 进油路、回油路的压力损失 运动部件最大速度为 ，最大流量为 127L/min，则液压油在油管中的流速 1v 为： scmcmcmdqv /4 1 8m i n/2 5 0 7 6m i n/ 101 2 7442321   管道流动雷诺数 1eR 为 7 0 1 811  vdvR e 1eR ＜ 2300，油液在管道内流动为层流，沿程阻力系数  eR。 进油管长度为 3m，沿程压力损失 1P 为： PaPavdlP 6222111 2   阀的压力损失 PaP  阀 ；那么进油路总的压力损失 进P为： 进P = 1P + 阀P = PaPa 666 )(  由于进出口管径相同，要求工作速度相同，所以估算压力损失也相同，那么回油压力损失 也为 兆帕； △ p=+= 20 其他元件可以看成是和主缸并联的，入出口辊道升降液压缸速度比较高，做一验算，其他元件忽略。 缸各工况时的压力损失验算 快进 速度为 ，需要的最大流量为 2L/min，进油管直径D=16mm，则液压油在油管中的流速 1v 为： scmcmcmdqv /2 5 0m i n/1 4 9 7 8m i n/ 42321   管道流动雷诺数 1eR 为 2 6 5 011  vdvR e 1eR ＜ 2300，油液在管道内流动为层流，沿程阻力系数  eR。 进油管长度为 10m，沿程 压力损失 1P 为： PaPavdlP 6222111   阀的压力损失 PaP  阀 ；那么进油路总的压力损失 进P为： 进P = 1P + 阀P = PaPa 666 )(  由于进出口管径相同，要求工作速度相同，所以估算压力损失也相同，那么回油压力损失 也为 兆帕； △ p=+= 要求工作压力 14 兆帕，而设计的是 18 兆帕，所以这点压力损失对系统的工作几乎没有影响。 通过对主缸、 入出口辊道升降 缸各工况的压力损失验算可知，液压系统的油路构及元件参数选择满足要求。 21 七．总结 每次做设计感触都不一样，这次是做毕业设计，感触颇多。 开始，我不会用 ＣＡＤ，在老师的强烈建议下，我学会了ＣＡＤ，出了我的第一张ＣＡＤ图纸，虽然很糟糕，颇有诟病，我还是很高兴，因为我又多了一项技能，以后的路就更好走一些。 刚开始，不知道老师的要求是什么，一直也找不到方向 感，稀里糊涂，一直在哪做三维绘图，也没有画好。 后来问老师才知道不要求做三维制图，也不用管缸，马达等实体如何空间布置，只做系统图和泵站图，这才明白，所想与所要求的背道而驰。 在明白了要求之后，出系统图。 元件选型感触最深，第一次我选择的元件很多，很杂，在画装配图时，怎么也组合不起来，很是纳闷。 仔细观察油孔布置之后发现力氏乐的六通径和油研的六通径空位置不一样。 这就明白了企业原来是这么保护自己的产品的独立性的。 第二次选择，全部选择力氏乐的电磁换向阀，液控单向阀，单向节流阀，可是，还是组合不到一起来，除非管式连接，可 是老师要求的是叠加阀，怎么就叠不起来呢。 问同学，又问老师，还是不明白，明明他们都可以叠加起来，为什么我的就不行。 思来想去，突然大笑，原来我是一个很烂的月老，非要把普通阀当作叠加阀用，能叠起来吗。 第三次，经历元件选型就比较顺利。 选完型之后开始画阀台，泵站图。 这个过程就像织茧一样，每一个动作都是在为最后的“房子”增砖添瓦。 也许我们只有经历了这样一个过程，将来才能走的更稳。 22 老师很好，很负责，对我们的错误是直言不讳，也指导我们应该如何做。 在老师的指导下，我顺利的完成了毕业设计。 谢谢老师。 八．参考资料 《液压元件系统设计》，主编周恩涛，机械工业出版社； 《机械设计手册》，成大先主编，第五版，化学工业出版社； 《新编液压工程手册》，雷天觉主编，北京理工大学出版社； 《机械设计手册》单行本，机械设计手册编委会，机械工业出版社； 《液压传动系统》，第三版，官忠范主编，机械工业出版社； 《机械设计课程设计》，唐增宝，常建娥主编，华中科技大学出版社； 《液压元件》 《流体力学》 23 九．翻译 原文： Volume or flow control valves are used to regulate speed. A was developed in earlier chapters。 the speed of an actuator depends on how much oil is pumped into it per unit of time. It is possible to regulate flow with a variable displacement pump, but in many circuits it is more practical to use a fixed displacement pump and regulate flow with a volume control valve. Flow Control Methods There are three basic methods of applying volume control actuator speeds. They are meterin, meterout and bleedoff. MeterIn Circuit In meterin operation, the flow control valve is placed between the pump and actuator. In this way, it controls the amount of fluid going into the actuator. Pump delivery in excess of the Metered amount I diverted to tank over the relief valve. With the flow control valve installed in the cylinder line as shown, flow is controlled in one direction. A check valve must be included in the flow control or placed in parallel with it for return flow. If it is desired to control directional valve. The method is highly accurate. It is used in applications where the load continually resists movement of the actuator, such as raising a vertical cylinder under load or pushing a load at a controlled speed. 24 MeterOut Circuit Meterout control is used where the load might tend to run away. The flow control is located where it will restrict exhaust flow from the actuator. To regulate speed in both directions, the valve is installed in the tank line from the directional valve. More often control is needed in only one direction and it is placed in the line between the actuator and direction valve. Here too a bypass check valve would be required for a rapid return stroke. BleedOff Circuit In a bleedoff arrangement, the flow control is bleed off the supply line from the pump and determines the actuator speed by metering a portion of the pump delivery to tank. The advantage is that the pump operates at the pressure required by the work, since excess fluid returns to tank through the flow control instead of through the relief valve. Its disadvantage is some less of accuracy because the measured flow is to tank39。 rather into the cylinder, making the latter subject to variations in the pump delivery due to changing workloads. Bleedoff circuits should not be used in applications where there is a possibility of the load running away. Types of Flow Controls Flow control valves fall into two basic categories: pressure pensated and nonpressure pensated. The latter being used where load pressures remain relatively constant and feed rates are not too critical. They may be as simple as a fixed orifice or an adjustable needle for free valve, although more sophisticated units may even include a check valve for free flow in the reverse direction. Use of nonpressure pensated valves is somewhat limited, since flow through an orifice is essentially proportional to the square root of the pressure drop across it. This means that any appreciable change in the work load would affect the feed rate. Pressure pensated flow controls are further classified as restrictor and bypass types. Both utilize a pensator or hydrostat to maintain a constant pressure drop across an adjustable throttle. The ByPass Typebines overload prote。