机械设计外文翻译--气动马达及工具-机械设计(编辑修改稿)

机械设计外文翻译--气动马达及工具-机械设计(编辑修改稿)内容摘要：

way shown,the speed decreases as the load motor can be stalled without any damage being done. A curve for horsepower versus speed for a rotarytype air motor is power output is at a maximum between zero and maximum output is proportional to the product of torque times angular or rotational speed(rpm). The speed,torque,and direction og rotation of an air motor can be controlled and adjusted to job example,reversible air motors are used to turn or screm studs into castings,when assembling air pressure to the air motor is regulated,so that the air motor stalls when the stud is driven to the correct this instance,the air motor starts off at high speed(very low torque),is quickly loaded so that it stalls,and is then air motor has no tendency to heat when it is overheating。 the motor can withstand repeated stalling and reversing without damage or air motor can accelerate(or speed up)rapidly,because the pressed air energy can be released at a high rate. Air motors are available mercially in sizes ranging from 1/10 7 horsepower to 50 horsepower,and in speed ranging from 20 rmp to 75,000 rmp. GENERAL FEATURES OF PNEUMATIC TOOLS Pneumatic tools represent a large number of airoperated machines that are usually transported to a work area,rather than transporting the work to the tool(as in machining some metals by machine tools).In many instances,the tool is either held entirely by the hands or guided and controlled by tool may be a manufacturing plant,the an outdoor construction job,the pressor may be a manufacturing plant,the pressor may be from the pressor system is fed by means of distribution piping through a filter,a pressure regulator,and a from the lubricator may be fed through a flexible hose to the pneumatic tools are usually supplied with pressed air at about 90 pounds per square inch, are three hroad classifications of pneumatic tools(1)rotary,(2)piston,and(3)percussion. In a typical rotary pneumatic tool,the air enters the tool handle,passes through a manually operated control valve,passes through the end plates,and enters a chamber of a vanetype air air pushes the rotor form the inlet to the the outlet,the air is discharged into the typical rotary air motor possesses three to five blades,rotates at speeds of 4000 to 25,000 rpm,and develops up to 3 spindle fastened to the rotor drives a set of plaary reduction gears to supply the desired output output shaft may be equipped with a chuck for holding a drill,grinder,or some other tool. The pistontype air motor is used for tools when higher horsepower and slower speeds are desired,as in hoists and heavydrills. The percussion or hammertype air motor is found in chippers, riveters,and pavement this type of machine,the air usually passes through an exhaust valve,and then is exhausted into the piston is moved back and the driving 8 stroke,the inertia of the piston provides a hammer blow or impact to a drill,a chisel,or a bit. Compressed air permits the use of tools are relatively pact,light in weight,flexible,portable,and easy to tools are used on a very light assembly work and on heavyduty constrution speed and direction of rotation of air motors can be controlled quickly,and they can be adjusted to serve requirements by means of a control valve which throttles the flow of pressed air to the motors do not have a tendency to bee hot when they are air motor presents no spark hazard in explosive atmospheres。 therefore,it can be used in oil refineries and other plants that the problem of examp。