I Hydraulic transmission device System composition
1) Power part
Hydraulic pump to supply working pressure oil source.
2) Executive part
Hydraulic cylinder, performing linear movement.
3) Control part - control valve, which controls liquid pressure, flow, flow speed and direction. 4) ) Auxiliary part\
Hydraulic oil, pipeline, oil tank, connectors, etc.: Om
Any Hydraulic transmission The device system can not be separated from the above four major high-definition watermark free 3. Main features of hydraulic transmission device
4) The actuating element can be used for stepless speed change, quick reversing and braking. 2) Compact structure, small size, can get very large working force. 3) Due to high pressure and poor sealing, it is easy to cause leakage.
2、 Performance parameters of hydraulic transmission device 1. Working pressure p
The working pressure divided here is the physical gas pressure, that is, p=F/AMPa1MPa=9.8kg/cm2. The working pressure of common hydraulic transmission devices is divided into three low and medium pressure areas, namely, 0~2.5MPa, 2.5~10MPa and more than 10MPa. The working pressure of common tap water is 0.4MPa
1. Flow q
Flow is the volume of liquid flowing through a pipe section in unit time, i.e. q,=Av. 3. Power P
Power is the work done in unit time, that is, P=pq, where the mechanisms of p and q are Pa and mR/s respectively, and the mechanism of P is watt, that is, w
2. Power P
Power is the work done in unit time, i.e. - P=pq, where the mechanisms of p and q are Pa and m3/s respectively, and the mechanism of P is W
3. Work efficiency
Since it is difficult to avoid working pressure loss, flow leakage loss and mechanical equipment loss during transmission, the rated power should be lower than the input power. The ratio of the two is the working efficiency of hydraulic transmission device, that is, n=P,/P, where P is the rated power.
3、 Work stress loss
In view of the viscosity of hydraulic oil, part of the energy is consumed when flowing out, which is reflected in the loss of working pressure.
The working pressure loss is divided into two categories. One is the working pressure loss caused by the friction of liquid flowing in the straight pipe, which is called the working pressure loss along the way; The other is the working pressure loss caused by the sudden change of the pipe section shape to change the liquid flow direction, which is called partial working pressure loss. The former is the working pressure consumed to get rid of the essential friction resistance. For example, the principle that oil pipelines need to be pressurized after a short interval is the same. The latter is to get rid of the external working pressure, such as the loss of working pressure caused by the right angle change of the pipeline to the hydraulic oil. Both are unavoidable.
4、 Fluid for hydraulic transmission device
The quality of hydraulic transmission oil has significant harm to transmission characteristics, so the characteristics of hydraulic transmission oil are
Corresponding regulations.
1. Features of hydraulic transmission oil
1) The relative density is the quality of the unit hydraulic oil. The higher the density, the higher the oil quality. The temperature does great harm to the relative density. The higher the temperature is, the smaller the relative density is; The increase of pressure will increase the density of oil docin.com
2) Compressibility and expansion chisels only change the volume with the change of pressure, which can be ignored in normal hydraulic transmission devices.
3) Viscosity is a crucial feature of hydraulic transmission oil. The higher the viscosity, the thicker the hydraulic oil is, and the lower the viscosity is
The hydraulic oil is thin.
2. Use of hydraulic transmission oil
When hydraulic transmission oil is used, the following aspects shall be referred to: 1) The viscosity is appropriate.
2) Good chemical stability, no mildew after long-term use.
3) The opening has many flash points and low cold filter point, which means that it is not easy to condense and fire.
5、 Summary
1) The basic working principle of hydraulic transmission device is to convey the driving force of operation by changing the sealing capacity. Pressure is caused by load. No external load, no pressure.
2) The hydraulic transmission device is mainly composed of four parts, which has the advantages of stepless speed change, compact structure and relatively large working force; The first defect is leakage.
3) The main parameters of hydraulic transmission device are pressure and flow. The working characteristics are equal pressure and equal volume standards in the liquid. Pressure loss is caused by internal friction and pipeline resistance, which is unavoidable in flow.
4) The hydraulic oil shall have proper viscosity, good stability, high open flash point and low cold filter point.
