液壓機與氣壓機不同及各自的優缺點

 

液壓機優點：

1、從結構上看，其單位重量的輸出功率和單位尺寸輸出功率在四類傳動方式中是力壓群芳的，有很大的力矩慣量比，在傳遞相同功率的情況下，液壓傳動裝置的體積小、重量輕、慣性小、結構緊湊、布局靈活。

2、從工作性能上看，速度、扭矩、功率均可無級調節，動作響應性快，能迅速換向和變速，調速范圍寬，調速范圍可達100：l到2000：1;動作快速性好，控制、調節比較簡單，操縱比較方便、省力，便于與電氣控制相配合，以及與CPU(計算機)的連接，便于實現自動化。

3、從使用維護上看，元件的自潤滑性好，易實現過載保護與保壓，安全可靠;元件易于實現系列化、標準化、通用化。

4、所有采用液壓技術的設備安全可靠性好。

5、經濟：液壓技術的可塑性和可變性很強，可以增加柔性生產的柔度，和容易對生產程序進行改變和調整，液壓元件相對說來制造成本也不高，適應性比較強。

6、液壓易與微機控制等新技術相結合，構成“機-電-液-光”一體化已成為世界發展的潮流，便于實現數字化。

 

液壓機缺點：

任何事物都是一分為二的，液壓傳動也不例外：

1)液壓傳動因有相對運動表面不可避免地存在泄漏，同時油液不是絕對不可壓縮的，加上油管等彈性變形，液壓傳動不能得到嚴格的傳動比，因而不能用于如加工螺紋齒輪等機床的內聯傳動鏈中。

2)在高溫和低溫條件下，采用液壓傳動有一定的困難。

3)為防止漏油以及為滿足某些性能上的要求，液壓元件制造精度要求高，給使用與維修保養帶來一定困難。

 

氣壓機優點:

1、以空氣為工作介質，工作介質獲得比較容易，用后的空氣排到大氣中，處理方便.

2、因空氣的粘度很小(約為液壓油動力粘度的萬分之一)，其損失也很小，所以便于集中供氣、遠距離輸送。

3、工作環境適應性好，特別在易燃、易爆、多塵埃、強磁、輻射、振動等惡劣工作環境中，比液壓、電子、電氣控制優越。

4、成本低，過載能自動保護。

 

氣壓機缺點：

1、由于空氣具有可壓縮性，因此工作速度穩定性稍差。但采用氣液聯動裝置會得到較滿意的效果。

2、因工作壓力低(一般為0.31.0MPa)，又因結構尺寸不宜過大，總輸出力不宜大于10～40kN。

3、噪聲較大，在高速排氣時要加消聲器。

4、氣動裝置中的氣信號傳遞速度在聲速以內比電子及光速慢，因此，氣動控制系統不宜用于元件級數過多的復雜回路。

 

 

 

Advantages of hydraulic press:

1. From the structure point of view, the output power per unit weight and output power per unit size of the four types of transmission modes are the most powerful, with a large ratio of moment and inertia. Under the condition of transmitting the same power, the hydraulic transmission device is small in size, light in weight, small in inertia, compact in structure and flexible in layout.

2. From the aspect of working performance, speed, torque and power can be adjusted steplessly, with fast response, fast reversing and speed changing, wide speed range, speed range of 100:1 to 2000:1; good action speed, simple control and adjustment, convenient operation and labor saving, easy to cooperate with electrical control and connect with CPU (computer), which is convenient to realize automation.

3. From the point of use and maintenance, the components have good self lubrication, easy to realize overload protection and pressure maintaining, safe and reliable; the components are easy to realize serialization, standardization and generalization.

4. All the equipment with hydraulic technology is safe and reliable.

5. Economy: the plasticity and variability of hydraulic technology are very strong, which can increase the flexibility of flexible production, and it is easy to change and adjust the production process. The manufacturing cost of hydraulic components is relatively low, and the adaptability is relatively strong.

6. Hydraulic pressure is easy to combine with new technologies such as microcomputer control to form the integration of "mechanical, electrical, hydraulic and optical", which has become the trend of world development and is easy to realize digitization.

Disadvantages of hydraulic press:

Everything is divided into two parts, hydraulic transmission is no exception

1) Because of the relative moving surface of hydraulic transmission, there is inevitably leakage, and the oil is not absolutely incompressible. Coupled with the elastic deformation of oil pipe, the hydraulic transmission can not get strict transmission ratio, so it can not be used in the inline transmission chain of machine tools such as processing thread gears.

2) It is difficult to use hydraulic transmission under high and low temperature conditions.

3) In order to prevent oil leakage and meet some performance requirements, the manufacturing accuracy of hydraulic components is required to be high, which brings certain difficulties to the use and maintenance.

Advantages of air compressor:

1. Using air as the working medium, the working medium is easy to obtain, and the used air is discharged into the atmosphere

2. Because the viscosity of air is very small (about one thousandth of the dynamic viscosity of hydraulic oil), its loss is also very small, so it is convenient for centralized gas supply and long-distance transportation.

3. Working environment adaptability is good, especially in the flammable, explosive, dusty, strong magnetic, radiation, vibration and other harsh working environment, better than hydraulic, electronic, electrical control.

4. Low cost, overload protection.

Disadvantages of air compressor:

1. Due to the compressibility of air, the stability of working speed is slightly poor. However, satisfactory results can be obtained by using gas-liquid linkage device.

2. Because of the low working pressure (generally 0.31.0mpa) and the size of the structure should not be too large, the total output should not be greater than 10-40kn.

3. The noise is big, so muffler should be added when exhausting at high speed.

4. The transmission speed of pneumatic signal in pneumatic device is slower than that of electron and light within the speed of sound. Therefore, pneumatic control system is not suitable for complex circuits with too many components.