QC/T 1081-2017Automotive electric power steering gear (English PDF)

3.1 Inertial delay

The phenomenon that the motor continues to rotate even after the steering wheel is stopped while the gear is in operation.

3.2 Maximum vehicle speed while offering assistant effort, Vmax

The maximum speed of the vehicle equipped with the gear while offering assistant effort.

4.1 General requirements

4.1.1 Gear

The gear is manufactured in accordance with the product drawings and technical documents approved by the prescribed procedures. The mechanical parts of the gear shall meet the requirements of QC/T 29096, QC/T 29097, QC/T 649 and QC/T 647 standards.

4.1.2 Operating temperature

The gear shall operate normally within the temperature range of -40°C to +85°C or +105°C (the electric power steering gear is installed outside the cab).

4.1.3 Relative humidity

The relative humidity that the gear can withstand shall be <= 95%RH.

4.1.4 Operating voltage

4.1.4.2 Allowable voltage variation range

a) 10.8V to 16V (nominal voltage of 12V);

b) 21.6V to 32V (nominal voltage of 24V).

4.2 Performance requirements

4.2.1 Functions

In the process of manually rotating the steering wheel at different vehicle speeds, it is felt that the rotation process shall be smooth, with no stagnation or no obvious vibration, and there shall be no inertial delay when stopping at any angle.

4.2.2 Input and output characteristics

At different vehicle speeds, the curve of the relationship between the input torque and the output torque (or force) of the gear, i.e., the input and output characteristics, shall meet the manufacturer's requirements.

4.3.5 Corrosion resistance

4.3.5.1 After the corrosion resistance test, the gear shall function normally and shall meet the requirements of 4.2.1.

4.3.5.2 The surface corrosion white spot area shall not exceed 20%, and red rust spots are not allowed.

4.3.5.3 The paint film shall meet the TQ6 requirements of QC/T 484.

4.3.6 Electromagnetic compatibility

4.3.6.1 Radio disturbance characteristics

The gear shall meet the requirements of GB/T 18655 and shall reach the Level III limit.

4.3.6.2 Electromagnetic radiation immunity

The gear shall comply with the requirements of GB/T 17619.

4.3.6.3 Electrical disturbances caused by electrostatic discharge

The gear shall comply with the provisions of GB/T 19951 and shall meet Class A requirements.

4.3.6.4 Electrical transient conduction along the power cord

The gear shall comply with the provisions of GB/T 21437.2 and shall meet Class A requirements.

4.4 Reliability

4.4.1 Forward drive wear

After the gear has been tested for 50,000 cycles, it shall meet the requirements of 4.2.1.

4.4.2 Reverse drive fatigue

After the gear has been tested for 217,000 cycles, it shall meet the requirements of 4.2.1.

4.5 Mechanical strength

5.1.5.2

The noise measurement accuracy shall not be less than 1dB(A) in the temperature range of (23±5)°C.

5.1.5.3

The temperature measurement accuracy shall not be less than 1°C in the temperature range of (23±5)°C.

5.1.5.4

The humidity measurement accuracy shall not be less than 10%RH in the temperature range of (23±5)°C.

5.2 Performance test items

5.2.1 Functions

The gear is installed on the test bench, and the system functions normally. The input terminal is in the straight driving position. The test load (equally divided, including 0 and Te) is applied to the output terminal. The vehicle speed is equally divided in the range of 0 to Vmax (according to an interval of 5km/h to 20km/h). The steering wheel is manually rotated left and right for testing, feeling smooth with no stagnation.

5.2.2 Input and output characteristics

5.2.2.1 The gear is installed on the test bench, and the system functions normally. The input terminal is in the straight driving position. The output terminal is rigidly fixed or applied with a linear load. Different vehicle speeds (equally divided, including 0 and Vmax) are set to rotate the input terminal uniformly at the speed of 20r/min to 30r/min to the left and right directions, so that the output torque or force reaches the rated value. RECORD the curve of the relationship between the input torque and the output torque or force at each vehicle speed (Figure 1).

5.3.1.2

PLACE at +85°C (applicable to C-EPS) or +105°C (applicable to P-EPS, R-EPS and X-EPS) for 96h.

5.3.1.3

After the test is completed, the test of 5.2.1 is directly carried out in the test chamber to check whether the gear functions normally.

5.3.2 Cold

5.3.2.1 The gear functions normally in accordance with the methods for Test A: Cold of GB/T 2423.1.

5.3.2.2 PLACE at -40°C for 96h.

5.3.2.3 After the test is completed, the test of 5.2.1 is directly carried out in the test chamber to check whether the gear functions normally.

5.3.3 Temperature alternation

5.3.3.1 The gear functions normally in accordance with the methods for Test N: Change of temperature of GB/T 2423.22.

5.3.3.2 COOL down to a cold environment at -40°C for 2h first, then INCREASE to a dry heat environment at +65°C for 2h to complete 5 cycles.

5.3.3.3 After the test is completed, the test of 5.2.1 is directly carried out in the test chamber to check whether the gear functions normally.

5.3.4 Composite temperature/humidity cycle

5.3.4.1 The gear functions normally in accordance with the methods for Test Z/AD: Composite temperature/humidity cyclic test of GB/T 2423.34.

5.3.4.2 A 10 cycles of composite temperature/humidity cyclic test is performed at -10°C to +65°C. Each cycle is 24h, and the change of temperature and humidity in each cycle is shown in Figure 4.

5.3.4.3 After the test is completed, the test of 5.2.1 is directly carried out in the test chamber to check whether the gear functions normally.

5.3.5 Corrosion resistance

5.3.5.1 It shall be carried out in accordance with the test methods for Test Ka: Salt mist of GB/T 2423.17.

5.3.5.2 After the gear is conducted with 24-h (applicable to C-EPS) or 240-h (applicable to P-EPS, R-EPS and X-EPS) salt mist test, CHECK the surface corrosion white spot area, and whether there are any red rust spots (not applicable to C-EPS). The paint film is inspected according to TQ6 […]

5.3.5.3

CHECK if the gear functions properly, and then the test of 5.2.1 is carried out.

5.3.6 Electromagnetic compatibility test items

5.3.6.1 Radio disturbance characteristics

The gear functions normally. According to the provisions of GB 18655, two tests are performed on the conducted emission of components and component conduction disturbance limits, and the radiated emission of components and component radiation disturbance limits, respectively.

5.3.6.2 Electromagnetic radiation immunity

The gear functions normally. According to the provisions of GB/T 17619, the free-field method and the high-current injection method are used to test in the shielding chamber. The free-field method has an immunity level limit of 30V/m. The high-current injection method has an immunity level limit of 60mA.

5.3.6.3 Electrical disturbances caused by electrostatic discharge

The gear functions normally. TEST according to test level III specified in GB/T 19951, and the vehicle speed is 8 km/h. The measuring points shall be around the motor, sensor and controller connectors and at the edge of the upper surface of the casing. There shall be no less than 10 measuring points.

5.3.6.4 Electrical transient conduction along the power cord

The gear functions normally and is tested in accordance with the test level III specified in GB/T 21437.2.

5.4 Reliability test items

5.4.1 Forward drive wear

5.4.1.1 The gear is installed on the test bench, and the system functions normally. The drive speed at the input terminal is 250°/s to 300°/s. The input terminal rotates to stay at both ends for 1 to 2s.

5.4.1.2 The vehicle speed is adjusted to 0km/h.

5.4.1.3 The load is applied to the left and right rods of the output terminal according to the test angles shown in (Figure 5) and given in (Table 1). The motor is allowed to cool down during the test.