You Stick Electric Motors Today

What do all manufacturers of electric motors have in common? They want to make their motors smaller and more powerful and also want to improve their efficiency. This is achieved, among other things, with the design of the laminated core and with the optimal integration of the magnets in the laminated core; in addition, the air gap between the magnet and the winding is kept as narrow as possible.

Adhesive technology in criticism

Bonding: insufficient

Connect better with adhesives

Established connection methods such as mechanical clamping or bandaging of magnets are increasingly reaching their limits, both with regard to the function of the motor and the production process: For example, with increasingly smaller motors, the required manufacturing tolerances also have to decrease further, which drives up costs. Rare earth magnets are increasingly being used, particularly for powerful motors. As they are susceptible to corrosion, they are given a passivation, nickel or epoxy resin coating that can be damaged during assembly and which would expose the magnets to direct environmental influences.

Compared to these conventional methods, gluing offers a number of advantages and is particularly suitable for three applications in the electric motor: for the connection of magnets and laminated core, for shaft and rotor as well as for stator and housing. Adhesives avoid friction or contact corrosion and are also impact-resistant, which is essential for the high dynamic forces in electric motors. Their damping effect reduces vibration noise and thus leads to an acoustic improvement. Thanks to their homogeneous stress distribution, they compensate for thermal stress that can arise, for example, with different thermal expansion coefficients between the stator and housing. In the case of the shaft, they prevent play and slip due to their gap-bridging properties.Finally, gluing also leads to lower manufacturing costs in many cases, since component tolerances can be larger, as mentioned, high and simple automation is possible and heat is not absolutely required.

New 2K adhesive for electric motors

Delo Industrial Adhesives has now developed a two-component epoxy resin especially for the flexible and efficient production of electric motors. Delo-Duopox SJ8665 is medium viscous and is suitable for motors with medium to high temperature requirements. The tough, hard adhesive has increased strength in this area of ​​application and is therefore suitable even for motors of insulation class H. At 80 ° C with 16 MPa on aluminum, the adhesive offers twice the tensile shear strength than standard 2K epoxy resins. The temperature-resistant product thus ensures a low aging of the connection. Even after 1000 hours of storage at 85 ° C and 85% humidity, it achieves the same strengths as before.

Two-component products convince with their good gap bridging as well as their peel strength and their tension compensation. Above all, they are used more, the larger and more solid the components are. However, they are increasingly used for motors of all sizes because they are more flexible in designing the production process than single-component products.

Adhesive technology in criticism

Bonding: insufficient

Fast and flexible production

By mixing both components, 2K epoxy resins harden completely at room temperature. This process can be accelerated using heat. In the case of the new epoxy resin, this is particularly quick and can be flexibly controlled by varying the time and temperature: At 80 ° C, 5 minutes to firmness and 10 minutes for complete curing. With induction heating of 100 ° C, the components can be fixed within 1 minute with a strength of 10 MPa - so the components can be processed directly. Compared to curing at higher temperatures, such as is required for single-component products, these moderate conditions enable a shorter heating-up time of the components and lower energy consumption in production.The adhesive can also be used for temperature-sensitive materials such as plastics or magnetized magnets. (br)