QC/T 550-2021Automotive buzzers (English PDF)

3.1 Buzzer

It is an electronic sounding device, which is installed in the cab of the vehicle, that can emit a prompt sound as required. The buzzer is a short-term fixed duty system.

According to the structure, it is divided into closed type, electromagnetic contact type, piezoelectric ceramic type, speaker type buzzer.

According to the wiring method, it is divided into single-wire, double-wire, multi-wire buzzer.

According to the sounding, it is divided into intermittent buzzer and continuous buzzer.

4.9.2.2 High temperature operating

After the buzzer is subject to 70 °C high temperature operating performance test, it is tested within 2 min. The performance shall meet the requirements of 4.2 and 4.3.

4.10 Resistance to rapid temperature changes with specified transition time

After the buzzer has undergone a rapid temperature change test with a specified transition time, its performance shall meet the requirements of 4.2 and 4.3.

4.11 Combined temperature/humidity cycle performance

The buzzer is returned to normal temperature, after the combined temperature/humidity cycle test; its performance shall meet the requirements of 4.2 and 4.3.

4.12 Vibration resistance

After the buzzer has undergone the vibration test, there is no crack or damage in appearance; its performance shall meet the requirements of 4.2 and 4.3.

4.13 Salt spray resistance

The buzzer is subjected to salt spray test. After 48 hours, there is no obvious corrosion on the appearance; its performance shall meet the requirements of 4.2 and 4.3.

4.14 Protection performance

The degree of protection of the buzzer shall reach IP5K4.

4.15 Free drop resistance

After the buzzer has been subjected to the free drop test, there is no crack or defect in the outer casing; its performance shall meet the requirements of 4.2 and 4.3.

4.16 Durability

After the buzzer has undergone the durability test, its performance shall meet the requirements of 4.2 and 4.3.

4.17 Electromagnetic compatibility

4.17.1 Radio disturbance characteristics

The conducted emission - voltage method, the conducted emission - current probe method, the radiated emission - ALSE method of the buzzer shall meet the relevant requirements of GB/T 18655-2018.

5.1 Test conditions

5.1.1 Sound pressure level measurement can be carried out, in an anechoic chamber, semi-anechoic chamber or open space (with no vertical reflection surface, within a radius of 7.5 m). The floor of the measurement area shall be a smooth concrete floor, which is a flat open floor composed of dense asphalt or similar hard materials, without obvious pores. In the vicinity of audible signal devices or microphones, other than observing instrument readings, no other personnel shall stay.

5.1.2 The test voltage shall be 14 V ± 0.2 V (12 V system), 28 V ± 0.2 V (24 V system).

5.1.3 Test environment conditions of buzzer

Unless otherwise specified, all tests shall be performed under the following conditions.

- Ambient temperature. 23 °C ± 5 °C;

- Relative humidity. 25% ~ 75%;

- Atmospheric pressure. 86 kPa ~ 106 kPa;

- Ambient noise sound pressure level shall be lower than 50 dB (A);

- The wind speed of the test site shall not be greater than 5 m/s.

5.2 Test instrument

5.2.1 The measurement of sound pressure level shall be carried out, using a first-grade precision sound level meter, that complies with the provisions of GB/T 3785.1. When measuring noise, it shall select the "F" time-weighted characteristic and "A" frequency-weighted characteristic of the sound level meter. Before and after the measurement, the sound level meter shall be calibrated, using a first-grade precision sound calibrator, which complies with the provisions of GB/T 15173. Without any adjustment, if the difference, between the last calibration reading and the previous calibration reading, exceeds 0.5 dB (A), the measurement result is considered invalid AND needs to be measured again.

5.2.2 The accuracy of voltmeter and ammeter shall not be lower than grade 0.5.

5.2.3 The power supply, which is used for the test, shall be an adjustable DC regulated power supply; the peak-to-peak value of the ripple voltage shall not be greater than 50 mV.

5.2.4 The accuracy of the sound frequency meter, which is used for the test, shall not be less than 20 µs.

5.11 Superimposed AC voltage withstand test

It shall be carried out, in accordance with the provisions of 4.4.2 in GB/T 28046.2-2019.

5.12 Temperature resistance test

5.12.1 Low temperature test

5.12.1.1 Low temperature storage

It shall be carried out, in accordance with the provisions of 5.1.1.1.2 in GB/T 28046.4-2011, for a duration of 24 h.

5.12.1.2 Low temperature operating

It shall be carried out, in accordance with the provisions of 5.1.1.2.2 in GB/T 28046.4-2011, for a duration of 24 h.

5.12.2 High temperature test

5.12.2.1 High temperature storage

It shall be carried out, in accordance with the provisions of 5.1.2.1.2 in GB/T 28046.4-2011, for a duration of 48 h.

5.12.2.2 High temperature operating

It shall be carried out, in accordance with the provisions of 5.1.2.2.2 in GB/T 28046.4-2011, for a duration of 96 h.

5.13 Resistance to rapid temperature change test with specified transition time

It shall be carried out, in accordance with the provisions of 5.3.2.2 in GB/T 28046.4-2011. It is maintained at each temperature point for 20 min, totally 100 cycles.

5.14 Combined temperature/humidity cycle performance test

It shall be carried out, in accordance with the provisions of 5.6.2.3 in GB/T 28046.4-2011, totally 10 cycles.

5.15 Vibration resistance test

Category M vehicle buzzer shall be implemented, in accordance with the provisions of 4.1.2.4.2 in GB/T 28046.3-2011. Category N vehicle buzzer shall be implemented, in accordance with the provisions of 4.1.2.7.2 in GB/T 28046.3-2011.

5.16 Salt spray resistance test

It shall be carried out, in accordance with the provisions of 6 in GB/T 2423.17-2008, for a duration of 48 h.

5.17 Protection performance test

It shall be carried out, in accordance with the provisions in 8.3.3 and 8.4 of GB/T 30038-2013.

5.18 Test of free drop resistance

It shall be carried out, in accordance with the provisions of 4.3.2 in GB/T 28046.3-2011.

5.19 Durability test

The durability test shall be carried out, at room temperature according to the circuit, as shown in Figure 2. The continuous buzzer works continuously for 100 h; the continuous buzzer works intermittently (power on for 15 s, power off for 15 s) for 200 h; the intermittent buzzer works continuously for 200 h; the intermittent buzzer works intermittently (power on for 15 s, power off for 15 s) for 500 h.

5.20 Electromagnetic compatibility

5.20.1 Radio disturbance characteristics

The conducted emission - voltage method, the conducted emission - current probe method, the radiated emission - ALSE method of the buzzer shall be carried out, according to the methods specified in Articles 6.2, 6.3, 6.4 of GB/T 18655-2018, respectively.

5.20.2 Transient conducted immunity along power lines

The transient conduction immunity test of the buzzer, along the power line, shall be carried out, according to the method specified in GB/T 21437.2. Pulses shall be applied to the buzzer's power lines and other connections, that may be connected to the power line.

5.20.3 Immunity to electromagnetic radiation

The test conditions for electromagnetic radiation immunity of the buzzer shall comply with the provisions of GB/T 33014.1; the test methods shall be carried out, according to the following methods, respectively.

- Anechoic chamber method. According to GB/T 33014.2;

- TEM cell method. According to GB/T 33014.3;

- Big current injection (BCI) method. According to GB/T 33014.4;

- 150 mm stripline method. According to GB/T 33014.5.