The main performance parameters and calculation of hydraulic pump in press brake bending machine

The main performance parameters of the press brake bending machine hydraulic pump refer to the pressure, displacement and flow rate, power and efficiency of the hydraulic bending machine hydraulic pump.

1. What is the working pressure, rated pressure and maximum allowable pressure of the hydraulic pump of the hydraulic bending machine? What is the relationship between the three?

   
   

① working pressure: refers to the pressure value of the output oil of the hydraulic pump of the press brake bending machine in the actual work, that is, the pressure established by the oil to overcome the resistance, also known as the system pressure. The working pressure of the hydraulic pump of thepress brake press brake is related to the external load. If the external load increases, the working pressure of the hydraulic pump is high.

② Rated pressure: refers to the maximum limit value of pressure allowed to be used when the pump is in continuous long-term operation under the premise of ensuring the volumetric efficiency, service life and rated speed of the hydraulic bending machine hydraulic pump. The rated pressure of hydraulic bending machine hydraulic pump refers to the maximum working pressure allowed to reach in continuous work of hydraulic bending machine hydraulic pump, that is, the pressure marked on the nameplate or product sample of hydraulic bending machine hydraulic pump.

(3) the highest allowable pressure: refers to the pump in a short period of time to allow the use of overloading the highest working pressure.

Considering the hydraulic bending machine hydraulic pump at work should have a certain pressure Gan, and a _ fixed leopard service life and volumetric efficiency, hydraulic bending machine hydraulic pump in normal work, the working pressure should be small hair or equal to the rated pressure of the pump, otherwise it will overload. In the hydraulic system, the working pressure of the quantitative pump is calmed and stabilized by the relief valve. The working pressure of the variable pump can be adjusted by the regulating device of the pump itself. The maximum allowable pressure is slightly higher than the rated pressure. There are some labels on the nameplate or product sample of the hydraulic bending machine, and some are not labeled.

2. What is the rated speed of the hydraulic bending machine hydraulic pump, the amount of high speed and the amount of low speed (commonly used unit is r/rain)?

(1) Rated speed, under rated pressure, according to the test results, it is recommended that the speed can run continuously for a long time and maintain high operating efficiency.

② Maximum speed: under rated pressure, the maximum speed of short operation allowed to ensure the service life and performance. Its value is mainly related to the structural form and self-priming capacity of the hydraulic pump of the hydraulic bending machine.

(3) minimum speed: in order to ensure the reliable work of hydraulic pump hydraulic bending machine or operation efficiency is not too low allowed minimum speed. What is called hydraulic bending machine hydraulic pump displacement, flow, theoretical flow, actual flow and rated flow? What do they have to do with it?

Discharge: in the case of not considering leakage, hydraulic bending machine hydraulic pump spindle per turn of a kitchen? The volume of the discharged liquid is known as the displacement, also known as the theoretical displacement, geometric displacement.

Displacement unit: 180 standard unit for mL/r, commonly used unit for mE/ro hydraulic bending machine hydraulic pump displacement depends on the hydraulic bending machine hydraulic pump seal cavity geometry size, different pumps, because of different parameters, the displacement is not the same.

Flow: refers to the volume of winnowing pump output oil in a unit time port.

Unit of flow: ISO standard unit is m3/s. The common unit is L/mm. Flow is also divided into theoretical flow, actual flow and rated flow.

Theoretical flow Qt. : refers to the benzene considering the leakage loss of the hydraulic bending machine hydraulic pump, hydraulic bending machine hydraulic pump in the unit of the volume of output oil. Its value is equal to the pump displacement V and pump shaft speed spore (r/min) product.

Actual flow Q0: refers to the actual volume of oil output by the hydraulic pump of the hydraulic bending machine in unit time. Because the outlet pressure of the pump in the working process is not equal to zero, there is internal leakage △Q(the higher the working pressure of the pump, the greater the leakage), so that the actual flow of the pump is less than the theoretical flow of the pump.

Rated flow: the actual output flow of the pump at rated speed and rated pressure. There is leakage loss due to the operation of the liquid aid pump.

So the actual output flow of the hydraulic pump of the hydraulic bending machine is less than the theoretical flow. The flow rate marked on the sample or nameplate of the pump is the rated flow rate of the pump.

4. What is the power of hydraulic pump of hydraulic bending machine?

The input power of the hydraulic pump of the hydraulic bending machine is the mechanical power, which is expressed by the product of the torque T and the angular velocity ∞ on the pump shaft. The output power of hydraulic pump of hydraulic bending machine is hydraulic power, which is expressed by the product of pressure evening and flow G.

(1) Input power P;

The input power of the hydraulic pump of the hydraulic bending machine is the output power of the motor, that is, the actual mechanical power required to drive the pump shaft.

(2) Output power P

The output power of the hydraulic pump of the hydraulic bending machine (KW) is expressed by the product of the actual flow rate and the daily pressure of the fever (PA)

5. What call hydraulic bending machine hydraulic pump mechanical efficiency, volume efficiency and total efficiency?

In fact, the hydraulic pump energy of the hydraulic bending machine is lost in the conversion process, so the output work is shaved and the input power is discharged as the power loss. The power loss of the hydraulic pump of the hydraulic bending machine has the mechanical loss and the volume loss. The loss of the friction car is the mechanical loss, and the loss caused by the leakage is the volume loss. The power loss is described by the efficiency.

(1) Mechanical efficiency

When the liquid flows in the pump, the viscosity of the liquid will cause the torque loss. When the parts in the pump move relative to each other, the mechanical friction will also cause the torque loss.

(2) Volume efficiency

Under the condition of a certain speed, the ratio of the actual flow and theoretical flow of the hydraulic bending machine hydraulic pump is defined as the volume efficiency of the pump, the leakage of the hydraulic bending machine hydraulic pump.

After the hydraulic bending machine hydraulic pump structure form, geometry size, the size of the leakage AQ mainly depends on the pump looking forward to export the press to use the impulse and Tibetan pressure pump speed (to quantitative pump) or displacement (to variable pump) how much the United States. Because the pump works under the condition of low speed or small displacement, its volumetric efficiency will be very low, so that it can not work normally.

(3) Total efficiency

The ratio of output power and input power of hydraulic pump of hydraulic bending machine,

The shaking efficiency of the hydraulic pump of a hydraulic bending machine is numerically equal to the product of the volumetric efficiency. The total efficiency, volumetric efficiency and mechanical efficiency of hydraulic pump of hydraulic bending machine can be measured by experiment.

(4) efficiency characteristics of the pump

The efficiency characteristic of the pump refers to the curve of the volumetric efficiency and the efficiency of the pump changing with the working pressure under a certain oil inlet temperature and a certain speed. Sometimes in order to comprehensively evaluate the efficiency of the pump, it is necessary to know its rhyme characteristic curve in the entire speed and pressure range.

(5) Static noise of hydraulic system

Hydraulic bending machine hydraulic pump noise is usually measured in decibel, hydraulic bending machine hydraulic pump noise mainly includes: flow pulsation, fluid flow impact, vibration of parts, friction and hydraulic impact, etc..

6. Give an example of how to calculate the motor power required to drive the pump.

It is known that the displacement of CBG2040 medium and high pressure gear pump is 40.6ml /r. The pump works under the conditions of 1450r/min and 10MPa pressure. The volumical efficiency of the pump is pulp =0.95 and the total efficiency is -0.9.