Stator Mount in Electric Motor

Application: Stator Mount in Electric Motor (in production since 2017) Volume: 100K pieces/year and increasing per schedule
Customer: Tier 1 Automotive Supplier (Powertrain Division)
Product: Pump Motor

Background: Customer needed to reduce cost by eliminating adhesives and fasteners used to mount an electric motor stator in a housing. The rede- sign also sought to reduce material costs by using an aluminum housing but concerns regarding thermal growth in extreme temperatures (−40°C to 125°C) needed to be addressed to avoid torque hold loss. The solution was a custom tolerance ring that ensured the waveforms were able to exert a holding force, yet allow for ease of assembly between mating components. It also successfully compensated for dimensional changes due to thermal fluctuations, eliminated adhesives/fasteners and a shrink fitting operation; which ultimately reduced production costs for the customer. Thanks to our design and production flexibility, the custom ring was able to go through multiple iterations and ring configurations to exceed the customer’s specification.

Case Study Data: The below characteristics of the ring and theoretical performance characteristics are based on component diameters:

  • Inside Member Diameter (OD): 1.0236”
  • Bore Diameter (ID): 1.0984”


Corrugation Height0.950.374
Theoretical Performance Characteristics for AN26X8S5
Compression (Inches)Radial Capacity (lbs)Torque Capacity (in-lbs)
0.0005 (1.3%)913
0.0010 (2.7%)916
0.0015 (4.0%)919
0.0020 (5.3%)9112
0.0025 (6.7%)9115
0.0030 (8.0%)9118
0.0035 (9.4%)721