GB/T 25627-2010Construction machinery - Power-shift transmissions (English PDF)

5.1 Test equipment

5.1.1 This Standard recommends to use open-testbed. The benches are comprised of the power machines, loading equipment, fastening and connecting devices and auxiliary systems.

5.1.2 DC motors, DC dynamometers, AC speed control motors and diesel engines may be selected for the power machines.

5.1.3 DC dynamometers, DC generators, AC speed control motors, electric eddy current dynamometers, hydraulic loading system or hydraulic dynamometers may be selected for the loading equipment. Testbed layout is shown in Figure 1.

5.1.4 Auxiliary systems include oil supply system and water supply system. The oil supply system shall satisfy the maximum oil supply pressure and flow-volume at the operation of the transmissions and may be continuously adjusted. Heating and cooling devices shall be installed in the system. Water supply system shall meet the flow-volume requirements and provide adjustable and stable water-flow.

5.1.5 The no-load power loss tests of the transmissions and the transmissions efficiency tests of the transmissions shall use independent oil supply systems.

5.2 Test accuracy and instrument precision

5.2.1 Stabilization precision during the measurement process shall meet the following requirements.

- - Test system torque ripple is not greater than ±0.5%;

- - The fluctuating value of rotating speed of the test systems shall not be more than ±5r/min. flow-volume of the variable-speed pumps and keep the oil level of the oil pan at the prescribed height.

5.4 Test method

5.4.2.2 Test procedure for the transmissions with torque converter

Test procedure for the transmissions with hydraulic torque converter.

a) The input rotating speed during the tests shall keep constant and comply with the stipulations in Table 4;

b) At the beginning of the test, first, make the output shaft idle, increase the input rotating speed to the set value and record the data after the running is fully stable; then, gradually load the output shaft as per the set increment, decrease the output rotating speed and keep the output rotating speed constant;

c) The interval of the loading torque shall be distributed arithmetically according to the torque of the output shaft and shall be properly reduced near the maximum efficiency and the working status transition points. The interval between the rotating speeds of the output shaft shall not more than one-tenth of the idle rotating speed of the output shaft;

d) The minimum value of the output shaft rotating speed of the transmissions is selected at the lowest shift-gear at the zero-sped working condition of the torque converter. The input torque shall be subject to the maximum torque of the matched engine. For other shift-gears, select n2<=0.3n1/iF(R).

5.4.2.3 Test procedures of separate transmissions

The following constant rotating speed test methods or constant torque test methods may be adopted.

5.4.2.3.1 Constant rotating speed test

a) Take two input rotating speeds for respective test. The high rotating speed n1=0.8nHe (for over-gear, select n1=0.6nHe). The low rotating speed n1=0.4nHe;

b) At the beginning of the test, first, make the power machine idle, increase the input rotating speed to the set value and record the data after the running is fully stable; then, gradually load the output shaft and keep the output rotating speed constant;

c) The interval for loading torque is arithmetically distributed in accordance with the input shaft torque;

d) The maximum value of the input torque of the transmissions shall be determined according to the input rotating speed, which is subject to the rated power transmitted by the transmissions.

5.4.2.3.2 Constant torque test

a) The input torque of the transmissions takes 2THe, 1.5THe, 1.0THe and 0.5THe respectively;

b) Start the power machines and increase the input rotating speed to the rotating speed of the initial test; increase the load to the set value, record data after the running is fully stable, then gradually increase the input rotating speed and keep the input torque constant;

c) The initial test rotating speed shall not be less than 600 r/min. The rotating speed interval shall be distributed arithmetically and shall not be more than 200 r/min;

d) The maximum value of the input rotating speed of the transmissions shall be determined according to the input torque, which is subject to the rated power transmitted by the transmissions;

e) Transmissions efficiency test shall record the following parameters. T1, T2, n1, n2, p1, p2, p3 (or p'3, p''3), p4, p5, t1, t2, Q. […]