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1、 英文原文 Hydraulic actuation system design and computation1. clearing about the design request to carry on the operating mode analysis. When design hydraulic system below, first should be clear about the question, and takes it as the design basis. Main engine use, technological process, overall layout
2、as well as to hydraulic gear position and spatial size request; The main engine to the hydraulic system performance requirement, like the automaticity, the velocity modulation scope, the movement stability, the commutation pointing accuracy as well as the request which to the system efficiency, warm
3、 promotes; Hydraulic system working conditions, like temperature, humidity, vibration impact as well as whether has situation and so on corrosiveness and heat-sensitive material existence.In in the above work foundation, should carry on the operating mode analysis to the main engine, the operating m
4、ode analysis including the movement analysis and the mechanical analysis, also must establish the load and the operating cycle chart to the complex system, from this understood the hydraulic cylinder or the oil motor load and the speed change as necessary the rule, below makes the concrete introduct
5、ion to the operating mode analysis content1.1 movements analysesThe main engine functional element according to the technological requirement movement situation, may use the displacement circulation chart (Lt), the speed circulation chart (vt), or the speed and the displacement circulation chart ind
6、icated, from this carries on the analysis to the movement rule.1.1.1 displacements circulation attempts LtThe chart 1.1 is the hydraulic press hydraulic cylinder moves the circulation chart, the y-coordinate L expression piston moves, the x-coordinate t expression starts from the piston to the repos
7、ition time, the rate of curve expression movement of plunger speed.Chart 1.1 displacements circulation chart1.1.2 speeds circulation chart vt (or vL)In the project the hydraulic cylinder movement characteristic may induce is three kind of types. The chart 1.2 is three kind of types hydraulic cylinde
8、rs v t chart, the first kind of like chart 1.2 center solid lines show, the hydraulic cylinder starts to make the uniform accelerated motion, then uniform motion,Chart 1.2 speeds circulation chartFinally uniform retarded motion to end point; The second kind, the hydraulic cylinder preceding partly m
9、akes the uniform accelerated motion in the overall travelling schedule, in another one partly makes the uniform retarded motion, also the acceleration value is equal; The third kind, the hydraulic cylinder one most above makes the uniform accelerated motion in the overall travelling schedule by a sm
10、aller acceleration, then uniform decelerates to the travelling schedule end point. Vt chart three velocity curve, not only clearly has indicated three kind of types hydraulic cylinders movement rule, also indirectly has indicated three kind of operating modes dynamic performance.1.2 mechanical analy
11、ses1.2.1 hydraulic cylinders loads and duty cycle chart1.2.1.1 hydraulic cylinders load strength computationsWhen the operating mechanism makes the straight reciprocating motion, the hydraulic cylinder must overcome the load is composed by six parts (1.1)In the formula: Fc In order to resistance to
12、cutting; Ff In order to friction drag; Fi For inertia resistance; Fg For gravity; Fm In order to seal the resistance; Fb In order to drain the oil the resistance.1.2.1.2 hydraulic cylinders cycle of motion various stages overall load strengthThe hydraulic cylinder cycle of motion various stages over
13、all load strength computation, generally includes the start acceleration, quickly enters, the labor enters, quickly draws back, decelerates applies the brake and so on several stages, each stage overall load strength has the difference.(1) starts the acceleration period: By now the hydraulic cylinde
14、r or the piston were in from static enough to starts and accelerates to the certain speed, its overall load strength including guide rail friction force, packing assembly friction force (according to cylinder mechanical efficiency m=0.9 computation), gravity and so on item, namely: (1.2)(2) fast sta
15、ge: (1.3)(3) the labor enters the stage: （1.4）(4)decelerates: (1.5)To the simple hydraulic system, the above computation process may simplify. For example uses the single proportioning pump to supply the oil, only must calculate the labor to enter the stage the overall load strength, if the simple system uses the limiting pressure type variable displacement pump or a pair of association pumps for the oil, then only must calculate the fast stage and the labor enters the stage the overall load strength.1.2.2 oil motor
