QC/T 529-2013Motor vehicles - Hydraulic power steering gear - Technical requirements and test methods (English PDF)

3.1 Center location

The 1/2 position of the total number of turns of the hydraulic power steering gear assembly (hereinafter referred to as the assembly).

3.2 Circle

After the input end of the assembly rotates from the center location to one direction to a specified angle, it returns to the center location; then it rotates to the specified angle in the other direction; then it returns to the center location. This forms a cycle.

3.3 Limited flow, Qn

When designing the hydraulic power steering gear, the specified rated output flow of the matched steering oil pump.

3.4 max. working pressure, pz

When designing the hydraulic power steering gear, the specified maximum working pressure of the matched steering oil pump, which is usually the opening pressure of the oil pump safety valve.

3.5 max. output torque, Mz

The maximum output torque of the recirculating ball hydraulic power steering gear's rocker shaft, which is specified in the design.

3.6 max. output force, Fz

The maximum axial output force of the rack and pinion hydraulic power steering gear's rack, which is specified in the design.

6.1 Performance requirements

6.1.1 The total number of turns of the steering gear and the rotation angle of the rocker shaft.

6.1.2 No-load torque

The variation range of the average value of left steering and right steering torque shall meet the design requirements. The variation range, from the maximum value to the minimum value, shall meet the design requirements. The variation range of adjacent peaks and troughs in the curve shall meet the design requirements.

6.1.5 Steering force characteristics

The steering torque and characteristic curve, at the highest working pressure, shall meet the design requirements; the symmetry of the curve shall not be less than 85%.

6.1.6 Return ability

The return time is not more than 5 s.

6.1.7 Internal leakage

The internal leakage volume meets the design requirements; after the reliability test, it does not exceed 150% of the design value of the leakage volume before the test.

6.1.8 External leakage

6.2 Reliability requirements

6.2.1 Reverse fatigue test

There shall be no extravasation and other abnormal conditions during the test; the assembly shall not be faulted.

6.2.3 Forced steering test

Abnormal conditions shall not occur during the test. The assembly shall not be faulted.

6.2.4 Reverse overload test

There shall be no extravasation and other abnormal conditions during the test. The assembly shall not be faulted.

6.2.5 Overpressure test

No extravasation shall occur during the test. The shell shall not have cracks or fractures.

6.3 Performance test method

6.3.1 The total number of turns of the steering gear and the rotation angle of the rocker shaft.

Install the assembly on the test bench. Measure the total number of turns of the input end, from one extreme position to another extreme position. Measure the rocker shaft angle.

6.3.2 No-load torque

Install the assembly on the test bench, the output end is unloaded. The input end rotates at a constant speed of (5 ~ 15) r/min.

6.3.3 Free clearance

Install the assembly on the test bench. Fix the output end rigidly in the center location.

The rotation speed of the input end is not more than 0.25 r/min. Measure the angle that the input end turns, when the pressure at the oil inlet of the assembly increases by 0.1 MPa in both directions.

6.3.6 Return ability

Install the assembly on the test bench. Let the input end unloaded. In the case of power, apply a return load of 6% of the maximum output torque, to the output end.

Respectively measure the time, for the output end to return from the two extreme positions to the center location. Take the longer time as the return time.

6.4 Reliability test method

6.4.1 Reverse fatigue test

Install the assembly on the test bench. Keep the input end at a clearance of about 0.5° in the center location. Use a stopper to limit its position. Load the output end in both directions, to ensure that the working pressure is the maximum working pressure. The frequency is (0.6 ~ 1.2) Hz. Completing 1 million alternating loads. Continue to test, according to 6.3.4, after this test.

6.4.3 Forced steering test

This test is not applicable to the semi-integrated hydraulic power steering gear. Install the assembly on the test bench. The oil pump does not work during the test. Rotate the input end, to adjust the output load, so that the torque at the input end is 125 N·m (assembly which has an output torque not greater than 2500 N·m) or 175 N·m (assembly which has an output torque greater than 2500 N·m). After completing 10 cycles, continue the test according to 6.3.4, after this test.

6.4.4 Reverse overload test

Install the assembly on the test bench. Under the powered conditions, fix the input end rigidly in the center location. At the connection between the steering rocker arm and the straight rod, quickly apply the load in the direction of 90° to the centerline of the steering rocker arm, until the load is equal to 3 times the maximum output force of the assembly, stop the test. Finish the test in two directions, respectively. After this test, continue to carry out the test according to 6.3.4.

7.1 Performance requirements

7.1.1 The total number of turns of the steering gear and the movement of the rack.

The total number of turns of the steering gear and the movement of the rack shall meet the design requirements.

7.1.7 Internal leakage

Same as 6.1.7.

7.1.8 External leakage

Same as 6.1.8.

7.1.9 Steering gear stiffness

Steering gear stiffness shall meet the design requirements.

7.1.10 Reverse drive loads

The reverse drive load shall meet the design requirements.

7.1.11 Noise

The noise shall meet the design requirements.

7.1.12 Vacuum test

There is no abnormal phenomenon, such as suction, sealing ring or sealing lip turning over.

7.2 Reliability requirements

7.2.2 Forward-rotation muddy water durability test. Same as 7.2.1

7.2.3 Forced steering test

There must be no fault to the assembly.

7.2.4 Reverse overload test

The assembly shall be free from fault, extravasation, or other abnormal conditions, during the test.

7.3 Performance test method

7.3.1 The total number of turns of the steering gear and the movement of the rack.

Install the assembly on the test bench. Measure the total number of turns, which are made by the input end, from one extreme position to another. Measure the rack movement.

7.3.2 No-load torque

Same as 6.3.2.

7.3.7 Internal leakage

Same as 6.3.7

7.3.8 External leakage

Same as 6.3.8

7.3.9 Steering gear stiffness

Install the assembly on the test bench. Fix the output end rigidly in the center location.

The flow rate is 0.5Qn. Rotate the input shaft. Draw the relationship curve, between the torque and the rotation angle of the input shaft.

7.4 Reliability test method

7.4.1 Reverse fatigue test

Install the assembly on the test bench. Install the inertia disc at the input end. Its moment of inertia is equivalent to the moment of inertia of the steering gear, which matches the steering wheel. Carry out the test under dynamic conditions.

7.4.2 Forward-rotation muddy water durability test

Install the assembly on the test bench. Carry out the test in sequence, according to the test conditions in Table 2.

7.4.4 Reverse overload test

Install the assembly on the test bench. Fix the input end rigidly in the center location, under the powered condition. Apply a load at one end of the rack. Stop the test, until the load is equal to twice the maximum output force of the assembly. Finish the test in two directions, respectively. After this test, continue to carry out the test according to 7.3.4.

7.4.5 Overpressure test

Install the assembly on the test bench. Install the stopper at the maximum displacement of the rack. Turn the input end, so that the pressure of the oil inlet of the assembly is 2pz. Keep it for 60 s. Complete it respectively in two directions. After this test, continue to carry out the test according to 7.3.4.

8.3 Sampling rules and inspection methods

Randomly select 3 sets, from the same batch of products, that have passed the exit-factory inspection, for type test. After all of the 3 sets are subjected to performance test, carry out the reliability test. […]