【正文】 re energy of the pressed air into piston’s high speed (more than ten meters per second) motion energy in a very short time. This is an impact cylinder design. Compared with mon cylinders, there is an extra middle lid (fitted with the cylinder body) with nozzle and exhausting small orifice. The cylinder is divided into three chambers by this middle lid and piston. For the sake of analysis, the working process can be simply divided into three steps. 1) Reset. The piston rod chamber is charged with air and the air in energy storing chamber exhausts out. The piston moves up until the seal gasket on the piston seals nozzle on middle lid. Piston chamber connects with the atmospheric via exhausting port. The pressure in chamber builds up to air source pressure, while the pressure in chamber falls down to atmospheric pressure. 2) Energy storage. When air enters chamber, it passes through the nozzle and acts on the piston. The area of the nozzle is so small that the air pressure cannot overe the resultant of the up thrust (produced by air exhausting in the piston rod chamber) and the friction against the cylinder. The nozzle is still closed and the pressure in chamber builds up gradually. 3) Impacting. When the ratio of the pressure in chamber to that in the piston rod chamber surpasses the ratio of the acting area in the piston rod chamber to the nozzle area the piston moves down to open the nozzle. Immediately this happens the pressed air accumulated in chamber acts on the whole of the piston via the nozzle, causing the piston to move down rapidly due to the high pressure difference of the piston rid. Because of the large 大連交通大學(xué)信息工程 學(xué)院 2020 屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 6 thrust produced by this high pressure difference, the piston accelerates rapidly and moves down with an extremely high speed, which develops high shock kiic energy. Air motors Air motors are pneumatic actuators which convert pressed air energy into rotating motion. Based on arrangement, they can be divided into vane type, piston type, gear type, diaphragm type, etc. Operation and characteristics of air motors (1)Vane motors: This is a simple vane motor operation. The rotor and the vanes are the only moving parts. The rotor is mounted offset in the casing, as can be seen. Air is admitted when the crescent shaped chamber is increasing in volume and delivered when decreasing. Torque is developed by pressure difference on the vanes, driving the rotor to turn in a counter clockwise direction for this motor. The air exhausts through orifices C and B. This direction of the rotor can be changed by merely changing the inlet port, ., air is admitted from orifice B for this motor. This is the soft characteristics of a vane motor under a certain working pressure. Small size motors are used for hand tools such as drills, grinders and screwdrivers. Larger sizes are used for winches, pump drivers, and drive motors on pneumatic drill rigs and general industrial applications. (2)Radial piston motors: Piston motors operate at much lower speeds than vane motors because of the greater inertia of the reciprocating parts. The typical radial motor has all connecting rids mounted on a mon crank (crank and connecting rod mechanism). The pressed air passes through the distribution valve from the inlet port and then enters the cylinder, driving part of the pistons to move reciprocating. The pistons’ reciprocating motion converts into crankshaft rotation through the crank and connecting rod mechanism. The crankshaft then drives the distribution valve which fixed on it to move simultaneously, causing the pressed air to enter different cylinders according to the angle change of distribution valve. The pistons move in turn to develop a continuous crankshaft rotation. At the same time, the cylinder opposite to the inlet cylinders is connected to the atmosphere and the high pressure air is released. The soft feature of the powerspeed and the torquespeed characteristic curves of piston motors under different working pressures are also very evident. (3)Diaphragm motors: Diaphragm motors are basically an application of diaphragm cylinders. The cylinder’s reciprocating motion converts into the ratchet wheel’s intermittent rotary output pressibility, . the output torque falls off with the increase of intermittent transmission speed under the constant working pressure. 大連交通大學(xué)信息工程 學(xué)院 2020 屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 7 Selection and application of air motors (1)Air motors’ selection: The selection of air motors is mainly base on its loaded conditions. In variable load occasions, the speed range and the torque needed to meet working conditions are principally considered. Working speed is also an important factor for constant load occasions. Other factors must be considered except for the above performancerelated factors, such as working pressure, gas consumption installation type, etc. (2)Air motors’ application: Air motors find more and more applications as the developing of the productivity. They can be used in all walks of life, particularly applicable for the o