Technical specification for automobile air-conditioning pressure switch
1.This standard specifies the technical requirements, test method inspection rules, marking, packaging, transportation and storage requirements for automotive air-conditioning three-state pressure switches.
This standard applies to the selection and acceptance of our company's three-state pressure switches .
2 Reference standard: none
3 technical requirements
3.1 General requirements
The pressure switch shall be manufactured in accordance with the provisions of this technical condition and in accordance with the drawings and technical documents approved by the prescribed procedures.
3.2 Appearance and dimensions
3.2.1 The appearance of the product is required to be smooth and clean, the parts are not damaged, the nameplate is clear, and the inserts are free of burrs.
3.2.2 The external dimensions should meet the requirements of the drawings.
3.3 Working pressure HP:OFF 3.14±0.2 Mpa DIFF 0.59±0.2MPa
M/P:OFF 1.37±0.10 Mpa ON 1.77±0.10Mpa Or according to the specific air conditioning system.
L/P:OFF 0.196±0.02 Mpa DIFF 0.0230.01MPa
3.4 Air tightness
Test according to method 4.5, pressurize the switch to 3.5MPa, and there should be no gas leakage at any part of the pressure switch.
3.5 Static pressure strength
Test according to method 4.6, keep for 5min under the pressure of 5.3MPa, the switch should not have any abnormality, and the working pressure should meet the requirements of 3.3.
3.6 Burst pressure
According to the test method of 4.7, the switch should not burst under the pressure of 8.0MPa.
3.7 Dielectric strength
Test according to 4.8, apply 500V AC voltage between the inserts and the outside, keep for 1min, the switch should not be break down .
3.8 Voltage drop
According to the test method in 4.9, the voltage drop of the switch should not be greater than 200mV between inserts 1 and 2, and the voltage drop between inserts 3 and 4 should not be greater than 100mV.
3.9 Withstand overload current
Test according to 4.10, the pressure switch should meet the requirements.
3.10 Impact test
After testing according to method 4.11, the pressure switch should not show any damage, and meet the requirements of 3.3 and 3.4.
3.11 Vibration test
After testing according to method 4.12, the switch should not show any damage, and meet the requirements of 3.3 and 3.4.
3.12 Durability test
After testing according to the method 4.13, the switch should meet the requirements of 3.3 and 3.4.
3.13 High temperature resistance
After testing in accordance with 4.14, the switch shall meet the requirements of 3.3 and 3.4.
3.14 Low temperature resistance
After testing according to the method 4.15, the switch shall meet the requirements of 3.3.3.
3.15 Resistance to temperature shock
After testing in accordance with the 4.16 method, the switch shall meet the requirements of 3.3 and 3.4.
4. Test method
4.1 Test conditions a. Ambient temperature: 246C. b. Relative humidity: 45-85%.
4.2 Measuring instruments and meters shall meet the following requirements and shall be accompanied by an inspection certificate within the valid period of use.
a. The resolution of temperature measuring instrument is 0.2C
b. The ratio of pressure measuring instrument is 2Pa
c. The accuracy of voltmeter, ammeter and ammeter shall not be lower than 2.5.
4.3 Appearance and dimensions: the visual inspection of the inspection switch is used, and the general measuring tool is used for the inspection of the outer dimension.
4.3 Appearance and dimensions: Visual inspection is used for appearance inspection of pressure switch, and general measuring tools are used for appearance inspection.
Low pressure: increase the pressure at a rate lower than 0.69MPa/min, write down the pressure value of the pressure switch, and then reduce the pressure after the switch is turned on at the same rate, and write down the pressure value of the switch and the result should meet 3.3 Claim.
4.5 Air tightness Input dry and clean nitrogen to the pressure switch to 3.5MPa at room temperature, and immerse in clean water for 1 min, which should meet the requirements of 3.4.
4.6 Static pressure strength test: Input static pressure (water or oil) to the pressure switch to 4.5MPa and keep it for 5 minutes. The result should meet the requirements of 3.5.
4.7 Burst test: input static pressure (water or oil to 8.0MPa, hold for 15s) to the pressure switch, the switch should not burst.
4.8 Absolute strength test: temperature 232C, relative humidity ≤80%, apply 500V between the inserts, apply 500V AC voltage between the inserts and the outer wall, keep for 1min, the pressure switch should not appear breakdown and flashover.
4.9 Voltage drop: The circuit connection is shown in Figure 2. When inserts 1 and 2 are connected with 5A current, the voltage drop when the switch contacts are connected should not be greater than 200m. When inserts 3 and 4 are connected with 1A current, the switch contacts are connected. The voltage drop through should not be greater than 100mv.
4.10 The circuit connection of overload current resistance is shown in Figure 2. The overload current shall be 1.25 times of the rated load current, and the on-time shall not exceed 1 min. After the test, the pressure switch shall meet the requirements of Article 3.9
4.11 Impact test: Perform 5 tests according to Figure 3, and the switch shall meet the requirements of 4.10.
4.12 Vibration test: The pressure switch is installed according to the loading position. The vibration frequency rises from 10Hz to 55Hz within 1min, and then drops to 10Hz. The amplitude is 2mm. After 24h vibration in the Z direction, the switch shall meet the requirements of 3.11.
4.13 Durability: Perform 500 cycles test according to Figure 4, and the pressure switch should meet the requirements of 3.12.
4.14 High temperature resistance: Put the switch in an environment with a temperature of 125°C for 48 hours and then return to the ambient temperature. The switch should meet the requirements of 3.13.
4.15 Low temperature resistance performance: Put the pressure switch in a low temperature box with a temperature of -402℃ for 48h and then return to the ambient temperature. The switch shall meet the requirements of 4.14.
4.16 Resistance to temperature shock: Carry out 10 cycles as shown in Figure 5. After the test, the switch shall meet the requirements of 3.15.
5.Inspection rules
5.1. General inspection:
5.1.1 The three-state pressure switch shall be inspected by the supplier's inspection department in accordance with the technical conditions and corresponding drawing requirements, and the quality certificate and factory test report shall be attached.
5.1.2 The inspection items, requirements and methods of general inspection are shown in Table 1.
5.1.3 When the total number of samples for inspection is less than 500, 5% of each batch shall be taken as the number of samples for sampling inspection, but not less than 10; when it exceeds 500, 25 for each batch.If two or more products are found to be unqualified during the sampling inspection, the batch of products will be regarded as unqualified. If one unqualified product is found, the random inspection will be doubled. If there are still unqualified products, the batch of products will be regarded as unqualified.
5.1.4 The sampling plan, acceptance items, defect classification, and qualified quality level can be carried out according to the content negotiated by both parties and specified in the product standard.
5.2 Type inspection
5.2.1 When there are the following cases, the pressure switch should be type tested and a type test report should be provided.
a. New trial switch
b. When the product's performance may be affected due to major changes in product structure, raw materials, and industrial products;
C. Stop production for more than half a year and resume production; d. Continuous production every full year.
5.2.2 Samples for type inspection shall be randomly selected from the user or finished product warehouse.
5.2.3 The items of the type inspection are all the items of the technical requirements, and the test grouping shall be as specified in Table 2.
5.2.4 If there is a sample that does not meet any of the requirements in the type inspection, a doubled number of samples should be taken from the batch of products for repeated testing of the unqualified items and related items, if there is still one When the sample does not meet any of the requirements, the batch of products is unqualified.
General inspection and type test of three-state pressure switch