Summary In recent years, exquisite, practical, convenient and fast electric kettles have begun to enter thousands of households, and China has become the world's largest electric kettle market. However, according to the latest information: The electric kettle is damaged or not working properly, most of which is caused by the damage of the temperature control components. Therefore, this paper proposes a design scheme of the temperature control switch life tester, which can estimate the life of the temperature control component, and then The purpose of extending the life of the electric kettle can be achieved by improving the temperature control switch. The test instrument designed by this scheme is mainly used for the life test of the kettle temperature control switch, and the test sample is installed. The tester can automatically complete the life test of the temperature control switch. The test phase does not require manual participation, and the test can be completed at the end of the test or on the way. Sound and light instructions. It has been verified that the instrument can achieve automated work, greatly reducing the workload of testers and improving test efficiency. 0 Preface In recent years, exquisite, practical, convenient and fast electric kettles have begun to enter thousands of households. After more than ten years of development, the electric kettle industry has a domestic market of tens of millions. China has become the world's largest electric kettle market, and its development prospects are broad. It is estimated that it is only in Guangdong, and the annual output of electric kettles exceeds 30 million units. However, the latest spot check shows that about 30% of the electric kettles on the market are unqualified, making it difficult to protect the consumer rights of the kettle. The industry has low barriers to entry, small scale enterprises, and poor quality awareness of workshop-style enterprises are the most direct causes of poor quality of electric kettles. In order to regulate the electric kettle market and protect the rights and interests of consumers, the safety standard of China's "Electric Kettle Performance Requirements and Test Methods" was implemented in May 2009. The quality of electric kettle products is unqualified, and more than 90% of them are caused by the failure of the electric kettle. The electric kettle has a short life and is easy to fail. It cannot be boiled after a period of use. The purpose of this paper is to develop and design an electric kettle tester for testing the life of the electric kettle switch, that is, the number of times the electric kettle switch is turned on. The tester does not require personnel to participate. As long as the test sample switch is installed, the sound and light indication can be issued when the test is completed or the fault occurs, and the fully automated work greatly reduces the workload of the tester and improves the efficiency. The tester studied in this paper has certain innovation, practicability and engineering, and it has been put into use in Lianjiang Di Aisi Electric Appliance Factory with good effect and certain economic and practical significance. 1 Temperature control switch structure and easy problem parts The structure diagram of the temperature control switch is shown in Figure 1. The main purpose is to use a dish-shaped bimetal as the temperature sensing component. As shown in Figure 2, the temperature control switch works as follows: when the temperature rises, the disk shape Corresponding deformations will occur, and when the temperature reaches a value at which the disc is deformed, the jump of the disc depends on the mechanical transmission of the other device, causing the contacts to act quickly to turn the current on or off. Operating temperature range: 30 ° C -300 ° C. The temperature control switch is prone to three problems: First, when the temperature of the bimetal disc of the temperature control switch itself is too high, the steam of the electric kettle cannot make the bimetal disc reach the temperature of the jump, resulting in the temperature control switch. Unable to cut off the current, the water of the electric kettle has been boiling and can not stop causing danger; secondly, the bimetal is a mechanically processed accessory. The jump and reset have mechanical life, and the material problem or processing problem has a direct impact on the life of the bimetal. Assume that 1 kettle is used normally for 5 times a day, and nearly 2,000 times a year. To ensure that the kettle is used for more than 5 years, you must ensure that the temperature control switch or bimetal lasts more than 10,000 times. The small spring of the switch is the same as the bimetal. It is also a mechanically processed accessory. Its life also directly affects the life of the temperature control switch and even the electric kettle. Therefore, the research and design of the temperature control switch life tester is essentially a life tester for testing bimetal and jump small springs. In the actual production test, the method of sampling is selected for testing. 2 technical solutions for temperature control switch tester The overall system diagram of the test instrument is shown in Figure 3 and can be divided into three parts: Circuit part, mechanical part and mounting base part. First, the circuit board part: This part takes the single-chip computer (MCU) as the core of intelligent control. The water temperature of the test kettle is collected by the DS18B20 temperature sensor, transmitted to the MCU for processing, and displayed in the LED or digital tube, the test encounters a fault or A sound and light indication will be given when the test is completed. The circuit schematic is shown in Figure 4. Second, the mechanical part: the electromagnet opening and closing part, to control the switch to open and close, test the kettle, provide real AC220V voltage and 1500W power loaded on the switch contacts. The mechanical structure is shown in Figure 5. Third, the base part: fixed circuit board of the tester, electromagnet, temperature control switch and switching power supply. Fourth, the software part uses C voice to develop the program of the underlying MCU. The program flow chart is shown in Figure 6. Zgar International (M) SDN BHD , https://www.sze-cigarette.com
