| The automotive relay plays an important part on the control, regulation and protection in the low-voltage electrical system, which is one of the most electronic components in automotive products. Nowadays, smaller and lighter design makes that the volume of the automotive relay shrinks and the cooling area is reduced accordingly. However, when the relay works normally, it will generate large amount of heat and cause the temperature of the internal components to raise, which is resulting in the failure of automotive relays.The automotive relay studied in the paper, works in the poor environment, must be able to run normally in a large temperature range from-40℃~125℃. In addition, the current load of the relay is relatively large. Therefore, thermal analysis for automotive relays has important theoretical and practical significance.In the paper, according to the principles of heat transfer, it studied the main way of heat transfer, built the mathematical model of the thermal field, calculated the main heat source inside the automotive relay and defined the method to load boundary conditions and heat generation considering the effects of convention and radiation. Besides, the paper built the solid model of the relay and simulated the steady temperature field of the relay in the long-term work system and the transient temperature field of the relay in the repeated short-term work system by using ANSYS software. According to the calculation, it concluded that the environmental temperature and current level had an effect on the temperature field of automotive relays. Finally, the temperature of the relay was practically measured and was compared with the simulation values. The results showed that it was entirely feasible to simulate the temperature field of automotive relays using finite element method. |
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