Created on:2021-05-17 14:34

Measurement method of no load displacement of hydraulic pump and motor

Measurement method of no load displacement of hydraulic pump and motor

(1) Scope. This standard specifies the measurement method of no-load displacement of positive displacement hydraulic pump and motor under steady-state condition and specified continuous speed. When tested as a pump, mechanical energy is input at the shaft end and hydraulic energy is output at the oil port; when tested as a motor, hydraulic energy is input from the oil port and mechanical energy is output at the shaft end.

Note: the accuracy of measurement is divided into three levels: A, B and C. see Appendix A.

(2) Terms and definitions

① Direction of rotation: observe the direction of rotation of the shaft from the end of the shaft.

Note: in case of doubt, it is better to use a diagram.

② Volume flow: the volume of liquid flowing through the cross section of the channel in unit time.

③ No load displacement: the volume of liquid discharged per revolution when the pressure difference between the outlet (inlet) and the inlet (outlet) of the pump or motor is zero. The value is calculated from the measured data of the pump or motor at different outlet pressure (pump) or inlet pressure (motor) under the specified test conditions.

The symbols and units of quantities used in this standard are shown in Table 3. The graphic symbols used in this standard conform to GB / t786.1.

 

Symbols and units

Symbol

名称

单位

量纲

  D

管道内径

  m

  L

  n

  转速

  r/min

  T-1

  p

  压力

  MPa(bar)

  ML-1T-2

  qv

  体积流量

  L/min

  L3T-1

  Qve

  有效流量

  L/min

  L3T-1

  Vi

  空载流量

  mL/r

  L3

  θ

  温度

  ℃

  θ

  υ

  运动黏度

M2/s

  L2T-1

  ρ

  质量密度

Kg/m3

  ML-3

① M = mass; L = length; t = time; θ = temperature.

② The letter symbols used are consistent with GB / T 17485.

③1bar=105 Pa=0.1MPa;1Pa=1N/m2。

Note: 1L = 10dm3.

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