QC/T 241-2024Air leakage detection methods of automobile wheels for tubeless tires (English PDF)

3.1 Leak rate

The amount of leakage caused by pressure difference per unit time.

3.2 Critical leakage rate

The leak rate threshold used to qualify a component.

5.1 Helium Detection Method

5.1.1 Detection equipment

The detection equipment shall have a sealing device that divides the wheel into two sealed chambers, the inner and outer, and it shall be feasible to evacuate the two sealed chambers. It shall be able to provide helium and detect the helium partial pressure in the sealed chambers in the wheel (see Figure 1).

5.1.3 Detection procedures

5.1.3.1 Seal the valve hole of the wheel.

5.2 Comparison Detection Method

5.2.1 Detection equipment

The detection equipment shall have a sealing device, two detection heads and an air inlet pipe (see Figure 2).

5.2.2 Detection conditions

There are no facilities that disturb the air near the detection equipment.

5.2.4 Evaluation of detection result

Compare the measurement difference between the two detection heads with the measurement difference corresponding to the preset critical leakage rate. When it is less than the measurement difference corresponding to the critical leakage rate, it shall be determined to be qualified. See Appendix A for the method of determining the critical leakage rate.

5.4 Differential Pressure Detection Method

5.4.1 Detection equipment

The detection equipment shall have a sealing device that divides the periphery of the rim weld into two sealed chambers, the inner and outer. It shall be able to vacuumize the sealed chambers, and there shall be a vacuum leak detector (see Figure 4).

5.4.2 Detection conditions

The inner and outer sides of the rim weld under detection shall be kept clean.

5.4.3 Detection procedures

5.4.3.4 Stop pumping and inflating the inner and outer sealed chambers of the rim.

5.4.3.5 Remove the fixture.

5.4.3.6 Remove the rim.

5.4.4 Evaluation of detection result

Compare the leak rate on the inside of the rim with the preset critical leakage rate. When it is smaller than the critical leakage rate, it shall be determined to be qualified. See Appendix A for the method of determining the critical leakage rate.

5.5 Water Detection Method

5.5.1 Detection equipment

The detection equipment shall have sealing devices, transparent water tank, air pressure gauge, as well as air intake and exhaust pipes (see Figure 5).

5.5.2 Detection conditions

The water quality shall be clean and the lighting shall be good.

5.5.3 Detection procedures

5.5.3.1 Seal the valve hole of the wheel.

5.5.3.2 Put the wheel between the sealing devices and tightly press the upper and lower rims to seal the inside of the wheel.

5.6 Compressed Air Method

5.6.1 Detection equipment

The detection equipment shall have sealing devices, air pressure gauge, as well as air intake and exhaust pipes (see Figure 6).

5.6.2 Detection conditions

The lighting shall be good.

5.6.3 Detection procedures

5.6.3.1 Put the rim into the device and tightly press it through the upper and lower rims, so as to seal the inside of the rim [see Figure 6 a)]. Or, put the rim weld into the sealing device and tightly press it through the rim section to seal near the outer weld or inner weld of the rim [see Figure 6 b)].

5.6.3.4 Check the weld for any air bubbles escaping.

5.6.3.5 Open the sealing device.

5.6.3.6 Remove the rim.

5.6.4 Evaluation of detection result

Within a specified period of time after the inflation reaches the specified pressure, if air bubbles escape from the rim weld, then, the rim shall be determined to be disqualified.

A.1 Definition of Wheel Leakage

Under room-temperature conditions, for wheel and tire assemblies, in a certain tire volume, fill the air pressure to the corresponding value, and within 6 months (180 days), the air pressure drop rate is greater than 10%.