QC/T 972-2014Technical requirements and test methods for automotive electronically controlled hydraulic power steering gear assemblies (English PDF)

3.6 Recirculating ball electronically controlled hydraulic power steering gear

The electronically controlled hydraulic power steering gear, whose transmission pair is recirculating ball type.

3.7 Rack and pinion electronically controlled hydraulic power steering

gear The electronically controlled hydraulic power steering gear, whose transmission pair is rack and pinion type.

3.8 Maximum speed Vmax

The maximum speed of the vehicle equipped with the assembly. The unit is km/h.

4.1 Performance

4.1.1 Recirculating ball electronically controlled hydraulic power steering gear.

4.1.1.1 The total number of turns of the steering gear AND the angle of the rocker shaft shall meet the design requirements.

4.1.1.2 No-load steering torque. For the variation range of the mean value of the left and right steering torques, it shall meet the design requirements. For the variation range from the maximum value to the minimum value, it shall meet the design requirements. For the variation range of adjacent crests and troughs in the curve, it shall meet the design requirements.

4.1.1.4 Function. In the process of rotating the input end, it feels smooth, without jamming; meanwhile the steering control valve can automatically return.

4.1.1.5 Return ability. The return time is <= 5 s.

4.1.1.7 The internal leakage shall meet the design requirements. After the changes within the range of (10.8 ~ 16.0) V (for 12V power system) OR (21.6 ~ 32.0) V (for 24 V power system), the controller shall be able to work normally.

4.1.3.3 Resistance to reverse polarity of power supply. The controller shall be able to withstand the reverse polarity test of the power supply, for 1 min, without damage. The controller shall be able to work normally after the test.

4.1.3.4 Withstand power supply overvoltage. The controller shall be able to withstand the power supply overvoltage test, for 1 min, without damage. The controller shall be able to work normally after the test.

4.1.3.5 Drop. The controller shall be able to work normally, after the drop test.

According to the test method of steering force characteristic, it meets the requirements for steering force characteristic performance. It allows partial damage of the control box AND deformation of the bracket.

4.1.1.3 Free clearance <= 5°

4.1.1.6 Steering force characteristics

The steering torque and characteristic curve, at the maximum working pressure, shall meet the design requirements. The symmetry of the curve shall be >= 85%.

4.2 Reliability

4.2.1 Recirculating ball electronically controlled hydraulic power steering gear.

4.2.1.1 Forced steering. There must be no abnormal conditions during the test; there must be no damage to the assembly.

4.2.1.2 Overpressure. No extravasation shall occur during the test. The shell shall neither be cracked nor broken.

4.2.1.3 Reverse fatigue. There must be no extravasation and other abnormal conditions during the test. There must be no damage to the assembly.

4.2.1.5 Wear resistance. There must be no extravasation and other abnormal conditions during the test. After the test, the free clearance is <= 12°; the assembly must not be damaged.

4.2.1.4 Reverse overload. Same as 4.2.1.3

4.2.2 Rack and pinion electronically controlled hydraulic power steering gear

4.2.2.1 Forced steering. The assembly must not be damaged.

4.2.2.2 Overpressure. During the test, the assembly shall be free from damage, extravasation, or other abnormal conditions.

4.2.2.5 Forward steering muddy water durability. Same as 4.2.2.3

4.2.2.3 Reverse fatigue

The internal leakage meets the requirements; there must be no leakage, damage, or falling off of seals.

4.2.2.4 Reverse overload. Same as 4.2.2.2

5.1.3 Test method

e) During the test, carry out measurement and data processing, respectively taking the 90% range of the left and right maximum rotation angles;

f) Draw the relationship curve, BETWEEN the input torque M AND the rotation angle theta (as shown in Figure 1).

5.2.1.3 Free clearance

a) Install the assembly on the test bench. Rigidly fix the output end in the middle position;

b) Rotation speed at the input end: <= 0.25 r/min;

c) Measure the angle that the input end turns, when the pressure at the fuel inlet of the assembly increases by 0.1 MPa, in both directions.

5.2.1.4 Function

a) Install the assembly on the test bench;

b) At the input end, apply a resistance torque, which is equivalent to one-third of the maximum resistance torque of the assembly;

c) Rotate the input end within the full stroke, to feel smoothness and continuity; meanwhile check the return of the steering control valve.

a) Install the assembly on the test bench, with the input end under no load;

b) In the case of presence of power, apply a return load of 6% of the maximum output torque, at the output end;

c) Respectively measure the time for the output end to return, FROM the two extreme positions TO the middle position; take the longer time, as the return time. the output terminal in the middle position. The flow rate is 0.5Qn. Rotate the input shaft. Draw the relationship curve between input shaft torque and rotation angle.

5.2.2.12 Noise

Under the condition that the controller receives the 0 km/h and Vmax vehicle speed signals, the tests are carried out according to the following methods:

a) Install the assembly on the test bench. The installation condition is equivalent to the actual vehicle;

b) Drive the input end, so that the oil pressure at the oil inlet is 0.5 pz and pz, respectively;

c) At the oil temperature of 50 °C, 80 °C, 100 °C, respectively, complete the test; the test environment noise is less than or equal to 30dB(A);

d) Use the sound level meter, to measure the sound value, at the 100 mm spherical surface, from the oil inlet of the control valve.

5.2.3 Electronically controlled device

For the recirculating ball AND rack and pinion electronically controlled hydraulic power steering gears, they shall meet the test method of the electronically controlled device.

5.2.3.3 Resistance to reverse polarity of power supply.

For the recirculating ball AND rack and pinion electronically controlled hydraulic power steering gears, take 3 sets from each to carry out all performance tests.

Connect the controller, as a load, normally. In the non-working state, when the input power voltage is the reverse voltage value, reverse the power polarity for 1 min. Reverse connection voltage value: The 12 V electrical system is (14 ± 0.1) V; the 24 V electrical system is (28 ± 0.2) V.

Under the condition that the controller receives the 0 km/h vehicle speed signal, the assembly is tested according to the following methods:

a) Install the assembly on the test bench. Keep the input end in the middle position, with a clearance of about 0.5°. Use a stopper to limit the position;

b) Load bidirectionally at the output end, to ensure that the working pressure is the maximum working pressure;

c) The frequency is (0.6 ~ 1.2) Hz;

d) After the completion of 1 million alternative loads, continue the test according to 5.2.1.4 after the test.

5.2.3.1 Self-check function

Install the electronically controlled device, under test, on the test bench. The electronically controlled device will work normally, to simulate various fault conditions set. Check whether the fault display lamp or the fault code alarm signal is normal.

5.2.3.2 Voltage fluctuations

The controller is connected to a power supply, which has adjustable output power. In the case of 12 V power system, the power supply voltage changes at (10.8 ~ 16.0) V. In the case of 24 V power system, the power supply voltage changes at (21.6 ~ 32.0) V.

5.3.1.4 Reverse overload

Under the condition that the controller receives the Vmax vehicle speed signal, the assembly is tested according to the following methods:

a) Install the assembly on the test bench;

b) In the presence of power, rigidly fix the input end at the middle position. At the connection between the steering rocker and the straight tie rod, quickly apply the load, at 90° to the center line of the steering rocker, until the load is equivalent to 3 times of the maximum output force; stop the test;

c) Complete it in two directions, respectively. After the test, continue to carry out the test according to 5.2.1.4.

5.3.1.5 Wear resistance

Input the vehicle speed signal to the controller, at a frequency of 0.5 Hz, according to the speed change mode of 0 km/h ~ Vmax ~ 0 km/h. Under the condition of normal operation of the electronically controlled valve, carry out the test according to the following methods:

a) Install the assembly on the test bench;

b) The test oil pressure is the maximum working pressure. Make the steering rocker reach the maximum output torque, during the test;

c) The input end runs at a speed of (20 ~ 30) r/min. The input end's angle is greater than or equal to 90% of the total angle;

d) After completing 25000 cycles, continue to test according to 5.2.1.3, 5.2.1.4, 5.2.1.6, 5.2.1.7 after the test, to check whether the assembly is working properly. completed, conduct a steering force characteristic test, to check whether the device is working properly.

5.3.3.2 Electromagnetic compatibility

a) Transient immunity. When the electric control device is energized, carry out the transient immunity test, of test pulse 1, 2a, 2b, 3a, 3b, 4, in accordance with the relevant requirements of 4.4 for transient immunity test, in GB/T 21437.2-2008. The grade of test impulse is grade III (in Appendix A).

b) Electromagnetic harassment. When the electric control device is energized, respectively carry out the following two tests, according to the relevant requirements of the measurement of parts and modules, in Chapter 6 of GB/T 18655-2010:

1) Measurement of conducted emission of parts;

2) Measurement of radiation emission of parts.

5.3.3.3 Temperature resistance

a) Resistance to low temperature. Place the electrically controlled device, at a temperature of (-40 ± 3) °C, for 96 h. After the test, place it at room temperature for 12 h. Continue to test according to the test method of steering force characteristics, to check whether the assembly is working properly.

b) Resistance to high temperature. Place the electrically controlled device, at a temperature of (125 ± 3) °C, for 96 h. After the test, place it at room temperature for 12 h. Continue to test according to the test method of steering force characteristics, to check whether the assembly is working properly.

c) Resistance to temperature changes. Carry out the test, according to the test Na: test method of temperature change, in GB/T 2423.22. Cool the temperature control box, to a low temperature of (-40 ± 2) °C. Put it in the electrically controlled device for 2 h. THEN, put it in a high temperature environment of (65 ± 2) °C for 2 h, reciprocating 5 cycles. After the test, continue to test, according to the test method of steering force characteristics, to check whether the assembly is working properly.

5.3.3.4 Resistance to combined temperature/humidity cycle

Carry out test, according to the relevant requirements of test Z/AD: test method of combined temperature/humidity cycle, in GB/T 2423.34. After the test, continue to test, according to the test method of steering force characteristics, […]