Xinfeng Magnetic Materials Co., Ltd. has found and summarized through the experience of co-designing with customers for many years: There are many factors for the failure of the permanent magnet synchronous motor rotor magnet bonding, and most of them are in the process. For the permanent magnet synchronous motor rotor magnet bonding, the following points need to be focused on:
1. The choice of binder. According to the specifications of the temperature range of the product in the “Basic Technical Conditions of Automotive Electrical Equipment”, the operating temperature range of the double-pinion and rack-assisted motors installed in the engine compartment is -40°~200°. Therefore, it is necessary to pay attention to the shear strength of the adhesive at 200°, and calculate the corresponding allowable shear force. Make sure that the allowable shear force at this time is much greater than the high force that the magnet is subjected to.
2. Control of surface cleanliness of motor parts. The cleanliness of the permanent magnet motor rotor core surface, magnet surface and gluing equipment is very important, which directly affects the bonding effect and the fatigue life of the rotor magnet after bonding. The fundamental reason for Toyota’s recall is that the surface cleanliness of the iron core is not up to standard, resulting in an unreliable magnet bonding.
3. The amount of binder. This is related to the surface area of the magnet. The basic requirement is that the adhesive layer should be evenly distributed over 2/3 of the area of the magnet. Too little binder will lead to unstable bonding.
4. Baking and holding time control. Strictly follow the instructions for selecting the binder to control the time of baking and heat preservation. It should be noted that the temperature of the baking and heat preservation equipment is evenly distributed.
5. Product online test. After the magnets are bonded and baked and cooled to room temperature, all rotors must be tested for bonding strength to ensure their safety. It is generally recommended to use a fixed rotor core to apply a thrust about 20 times its maximum force to the magnet.
Post time: Aug-18-2021