3.1.15 Electric Motors

Millions of electric motors are manufactured worldwide every year. While the design and performance requirements of these motors vary, their manufacturers share many of the same challenges. As technology advances, the demand for smaller motors with greater performance increases, and motors must operate at higher temperatures and at faster rotational speeds. To remain competitive, motor manufacturers must eliminate waste and become as efficient as possible. To accomplish this, design and manufacturing teams must work closely together to improve their products and processes. Electric motors are more prevalent in automobiles than ever before, forcing motor designers to find new ways to maximise performance and efficiency while being as cost-effective as possible. Electric motor and generator manufacturers have used adhesives and sealants to improve performance, facilitate manufacturing processes and reduce costs for more than 60 years. Adhesives not only make improved manufacturing processes and speeds possible but also allow designers to select new or lightweight materials to enhance performance and improve reliability.

Table 7 Comparison of electrical motor assembly methods
E-MOTORS Conventional/Traditional Method Adhesive Solution
Permanent Magnet
  • A permanent magnet generates the necessary magnetic fields
Mechanical Fastening/Slots/Clips
  • May lead to corrosion due to the presence of gaps
  • Involves additional process and time for magnet assembly
  • Challenging to automate
  • Limited impact/vibration resistance during operation at high operating temperatures
  • Might abrade/chip the magnet’s surface, resulting in repair/rework/rejections
Magnet Bonding Solutions
  • Fast fixturing/curing options (<10 seconds) are available, which adhere to almost all magnetic material
  • Automation proven for magnet bonding in E-motors
  • More reliable and efficient; helps to avoid rework/rejection time
  • Reduced steps/processes compared to conventional methods for magnet assembly
  • Proven room temperature curing options available, eliminating the need for heat curing
  • Bearing to shaft & housing rotor to shaft
Press Fit/Shrink Fit/Knurling on shaft
  • Precise machining to achieve exact tolerances for assembly – additional time
  • Heating and quenching process for shrink fit method for retaining assembly adds time and cost
  • Knurling operation on the shaft – additional process
Retaining Solutions
  • Allows for relaxed tolerances – no precise machining
  • Reduced tolerance eliminates the need for a heat shrink fit and quenching process
  • Adhesive application can be automated to control the adhesive quantity and ensure fast, reliable application
  • Number of processes reduced
  • Significantly reduced rework/rejection time

Preparing is caring

Check out LOCTITE® XPLORE's e-learning on surface preparation. It's free, fun and takes less than 10 mins.

Log in and select the chapter Introduction to Bonding and select Prepare to be Amazed to learn more.

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