分類空氣壓縮機是氣源裝置中的主體，它是將原動機的機械能轉換成氣體壓力能的裝置，是壓縮空氣的氣壓發(fā)生裝置。空氣壓縮機的種類很多，按工作原理可分為容積型壓縮機和速度型壓縮機。容積型壓縮機的工作原理是壓縮氣體的體積，使單位體積內氣體分子的密度增加以提高壓縮空氣的壓力；速度型壓縮機的工作原理是提高氣體分子的運動速度，使氣體分子具有的動能轉化為氣體的壓力能，從而提高壓縮空氣的壓力。2.活塞式空氣壓縮機的工作原理在氣壓傳動中，通常采用容積型活塞式空氣壓縮機。這里介紹兩種典型結構，用來幫助理解空氣壓縮機的工作原理。圖3.33（動畫）和圖3.34（動畫）分別給出了立式、臥式空氣壓縮機的工作原理圖。立式空氣壓縮機的氣缸中心線與地面垂直，臥式空氣壓縮機的氣缸中心線則與地面平行。原動機的回轉運動經曲柄連桿機構轉換為活塞的往復直線運動?？諝鈮嚎s機中的進氣、排氣過程與泵的吸油、壓油過程類似，這里不再贅述。3.空氣壓縮機的選擇空氣壓縮機的選擇主要依據氣動系統(tǒng)的工作壓力和流量。氣源的工作壓力應比氣動系統(tǒng)中的工作壓力高20%左右，因為要考慮供氣管道的沿程損失和局部損失。如果系統(tǒng)中某些地方的工作壓力要求較低，可以采用減壓閥來供氣?？諝鈮嚎s機的額定排氣壓力分為低壓（0.7~1.0MPa）、中壓（1.0~10MPa）、高壓（10~100MPa）和超高壓（100MPa以上），可根據實際需求來選擇。

The classified air compressor is the main part of the air source device. It is a device that converts the mechanical energy of the prime mover into gas pressure energy, and it is a pressure generating device for compressed air. There are many kinds of air compressors, which can be divided into volumetric compressors and speed compressors according to the working principle. The working principle of volumetric compressor is to compress the volume of gas, increase the density of gas molecules per unit volume, and increase the pressure of compressed air; The working principle of speed compressor is to increase the movement speed of gas molecules, so that the kinetic energy of gas molecules can be converted into gas pressure energy, so as to increase the pressure of compressed air. 2. Working principle of piston air compressor in pneumatic transmission, volumetric piston air compressor is usually used. Here are two typical structures to help understand the working principle of the air compressor. Figure 3.33 (animation) and figure 3.34 (animation) show the working principle diagrams of vertical and horizontal air compressors respectively. The cylinder center line of the vertical air compressor is vertical to the ground, and the cylinder center line of the horizontal air compressor is parallel to the ground. The rotary motion of the prime mover is converted into the reciprocating linear motion of the piston through the crank connecting rod mechanism. The air intake and exhaust processes in the air compressor are similar to the oil suction and oil pressure processes of the pump, which will not be repeated here. 3. Selection of air compressor the selection of air compressor is mainly based on the working pressure and flow of pneumatic system. The working pressure of the air source should be about 20% higher than that in the pneumatic system, because the along-line loss and local loss of the air supply pipeline should be considered. If the working pressure in some parts of the system is low, the pressure reducing valve can be used to supply air. The rated exhaust pressure of the air compressor is divided into low pressure (0.7~1.0mpa), medium pressure (1.0~10mpa), high pressure (10~100mpa) and ultra-high pressure (above 100MPa), which can be selected according to the actual demand.