QC/T 568-2019Specifications and bench test methods for automotive manual transmission assemblies (English PDF)

4.3 Cleanliness

The cleanliness of the non-disassembled transmission assembly shall be calculated according to formula (1):

Where:

G - The actual measured impurity mass of the transmission assembly;

K - Objective evaluation coefficient of cleanliness, i.e., impurity content per liter of lubricating oil, mg/L; the allowable K value is as shown in Table 1;

Le - The rated volume of lubricating oil for transmission assembly, L.

4.4 Fatigue life

Complete the test according to the method specified in 5.5. During the test, there shall be no abnormal noise, oil leakage, etc., meanwhile the main parts and components shall not be damaged, such as fracture, pitting, peeling, jamming, etc. (for tooth surface pitting, passenger vehicle: single tooth surface's accumulative pitting area is more than 4 mm² or the depth exceeds 0.5 mm; commercial vehicles: A single pitting area exceeds 4 mm², or a single tooth surface's accumulative pitting area exceeds 20% of a single tooth surface).

4.5 Shift life

For the transmission with synchronizer, the test shall be completed according to the method as specified in 5.6; any gear shall not show continuous gearing failure or 5 consecutive gear shifting shocks or gear knocking.

4.6 Static torsion strength

The test is completed according to the method specified in 5.7; the static torsion strength's reserve factor shall meet the following requirements: the forward gear K of passenger cars is greater than or equal to 2.5; the reverse gear K is greater than or equal to 2.0.

5.1.1 Test sample

5.1.1.1 In one of the following situations, the bench test shall be carried out according to 5.2 ~ 5.14:

a) When developing new products;

b) After the new product is finalized, there are major changes in structure, material, process, etc. that may affect product performance.

5.1.1.2 Sampling shall be carried out according to the following requirements:

a) The mass production test samples shall be taken from the qualified products after exit-factory inspection according to GB/T 2828.1;

b) In the new product development stage, the test sample is a trial prototype;

c) Customer sampling or entrusted party sending samples.

5.1.1.3 At least 2 test samples are taken for each test item; if all test samples are qualified, the item is judged to be qualified.

5.1.1.4 Before the test, test and record the test samples according to the requirements of the test items.

5.1.1.5 One transmission can be subjected to multiple tests without affecting subsequent tests.

5.1.2 Run-in before test

5.1.2.1 Before the fatigue life test, transmission efficiency test, noise test, high-speed test, the test samples shall be run-in. According to the input shaft speed, input torque, run-in time specified in Table 6 to run-in the gears at each gear position, at an oil temperature of less than or equal to 80 °C.

5.5.2 Test procedure

5.5.2.1 Install the transmission on the test bench and fill in lubricating oil as required.

5.5.2.2 Perform run-in according to 5.1.2.1. Change the oil after run-in (category M2, M3 and N may not change oil).

5.5.2.3 The test oil temperature is 80 °C ± 5 °C.

5.5.2.4 The input speed is the maximum speed at the engine's maximum torque point ± 10 r/min. When the engine speed at the maximum torque is close to or less than 1450 r/min, it may take 1450 r/min.

5.5.2.5 The number of tests for each gear position of the transmission shall be carried out according to the requirements in Table 8.

5.5.2.6 The test is carried out in sequence from low gear to high gear and reverse gear. The whole test can be divided into 10 cycles.

5.7.1

The static torsion strength test shall have the following equipment and conditions:

a) Driving device;

b) Test tooling;

c) Torque sensor, measurement accuracy is ± 1% FS;

d) Angle sensor, measuring accuracy is ± 0.5°;

e) Measurement data recorder.

5.7.2 Test procedure

5.7.2.1 Install the transmission on the test bench.

5.7.2.2 The input shaft and output shaft only bear torque; no additional bending moment is allowed.

5.7.2.3 During the test, the gear tooth's loaded working surface is the same as the vehicle driving condition.

5.7.2.4 The output shaft is fixed; the torsion speed of the input shaft does not exceed 0.2 r/min.

5.7.2.5 Reliably hook the transmission into the lowest gear which has a speed ratio of less than 10; load at a constant speed at startup until damage occurs or the torque reaches the specified value; record the torque and rotation angle of the input shaft when it is damaged, or the angle of input shaft when the specified torque is reached.

5.7.3 Processing of test results

Calculate the static torsion strength's reverse factor K by formula (2):

Where:

T - Torque recorded at the end of test, N · m;

Tmax - Rated input torque of the transmission, N · m.

If the static torsion strength's reverse factor meets the requirements of 4.6, the test is determined to be qualified.

5.8.3

5.8.3.2 The comprehensive transmission efficiency is the average measured efficiency of each forward gear (not including the first gear).

5.8.3.3 If the requirements of 4.7 are met, the test is determined to be qualified.

5.9 Noise test

5.9.1 Test conditions

5.9.1.1 Test field

It is carried out in a semi-anechoic chamber, no obstacles shall be placed within 2 m of the measurement field; the distance between the test bench and the wall is 2 m.

5.9.1.2 Test equipment

The noise test shall include the following equipment:

a) Driving device;

b) Power suction device;

c) Test tooling;

d) Speed, torque, temperature measuring instrument;

e) Acoustic data acquisition and processing system;

f) Safety device.

5.9.2 Test procedure

5.9.2.1 Install the transmission on the test bench and fill in lubricating oil as required. Install 3 microphones (such as microphones) on the left, right and above the transmission; meanwhile the distance between the 3 microphones and the transmission surface is 1000 mm ± 10 mm. The mounting surface formed by the 3 microphones shall be perpendicular to the input shaft's center line of the transmission and is at half the length of the transmission; the two microphones on the left and right shall be the same height as the transmission input shaft. The schematic diagram of microphone installation is as shown in Figure 1.

5.9.3

5.9.3.3 If the requirements of 4.8 are met, the test is determined to be qualified.

5.10 Gear-shift performance test

5.10.1 Dynamic gear-shift performance test

5.10.1.1 Test conditions

The dynamic gear-shift performance test shall include the following equipment and conditions:

a) A drive device that can drive the output shaft of the transmission;

b) Clutch driven disc or inertia disc of simulated clutch driven disc;

c) Test tooling;

d) Force sensor;

e) Timer to record the number of reciprocating shifts;

f) Transmission oil temperature gauge;

g) Tachometer;

h) Shift actuator;

i) Safety device;

j) The fluctuation of the transmission output shaft speed during gear shifting shall be less than or equal to 5% of the set speed.

5.10.1.2 Test procedure

5.10.1.2.1 Install the transmission on the test bench and fill in lubricating oil as required.

5.10.1.2.2 Run-in according to 5.1.2.2. Change the oil after run-in (category M2, M3 and N may not change oil).

5.10.1.2.3 Drive the transmission from the output end of the transmission. Alternately make at least 20 gear shifts between two adjacent gears. For category M1: It is 50% of the engine's maximum speed for upshift; it is 32% of the engine's maximum speed for downshift. For category M2, M3, N: It is 65% ~ 70% of the engine's maximum speed for both upshift and downshift.

5.10.1.2.4 The shifting force is set to the designed value.

5.10.1.2.5 The temperature of the lubricating oil in the test can be within the appropriate range and install it on the gear selection rocker arm of the transmission; make the force measurement direction be consistent with the direction of the gear selection force. When the input shaft and output shaft of the transmission are in stationary state, push the gear selection rocker arm at a constant speed to select gears; perform 3 tests in the sequence of neutral gear-> forward gear selection limit position-> neutral gear-> reverse gear selection limit position->neutral gear.

5.10.2.3 Processing of test results

5.10.2.3.1 Shift performance: Calculate the arithmetic average of 3 gear-shifts. According to the transmission lever ratio between the synchronizer gear sleeve and the force measuring point of the shift rocker arm, it is converted to the synchronizer gear sleeve, which is the static gear shifting force and static de-gearing force at this gear position.

5.10.2.3.2 Gear selection performance: Read the maximum gear selection force value in the gear selection process according to the curve; calculate the average value of the 3 sets of data; convert it into the gear selection force value at the gear selection position at the inner shift head.

5.10.2.3.3 If meeting the requirements of 4.9, the test is determined as qualified.

5.11 Dynamic sealing test

5.11.1 Test conditions

The dynamic sealing test shall include the following equipment:

a) Driving device;

b) Speed and temperature measuring instruments;

c) Transmission lubricating oil's temperature control device;

d) Safety device.

5.11.2 Test procedure

5.11.2.1 Install the transmission on the test bench and fill in lubricating oil as required.

5.11.2.2 Put on the highest gear or reverse gear.

5.11.2.3 Start the transmission test bench, so that the input speed of the transmission reaches the speed specified in Table 11.

5.11.2.4 The test time starts to be calculated after the test oil temperature reaches the specified temperature.

5.12.2

5.12.2.4 The longest test time for each gear position is 6 h. If it reaches a certain temperature in advance and keeps it unchanged for 30 min (the fluctuation of oil temperature does not exceed 1 °C), the test shall be ended. If the test time exceeds 6 h but the oil temperature has not reached a stable temperature, the test shall be terminated. If the oil temperature exceeds the designed maximum allowable temperature of the transmission, the test shall be terminated early.

5.12.2.5 Continuously record the curve of the transmission oil temperature with time.

5.12.3 Processing of test results

If meeting the requirements of 4.11, the test is determined as qualified.

5.13 High-speed test

5.13.1 Test conditions

The transmission's high-speed test shall include the following equipment:

a) Driving device;

b) Loading device;

c) Test tooling;

d) Speed, torque, temperature measuring instrument and timer;

e) Safety device.

5.13.2 Test procedure

5.13.2.1 Install the transmission on the test bench and fill in lubricating oil as required.

5.13.2.2 Run-in according to 5.1.2.1. Change the oil after run-in.

5.13.2.3 The test steps are as follows:

a) The test oil temperature is 100 °C ± 10 °C

b) The input speed is the maximum engine speed ± 10 r/min;

c) The input torque is the torque corresponding to the highest engine speed ± 5 N · m;

d) The test time at each gear position is determined according to the requirements of Table 12;