Following in the slipstream of the aerospace industry, automotive OEMs are increasingly turning to new materials and technologies to reduce weight and improve energy efficiency in their products. The use of magnet-based motor designs is one approach that is translating successfully to the automotive industry.

Advanced material enabling lighter vehicles and higher efficiency motors include:

• High performance samarium cobalt
• Laminated magnet configurations
• Carbon fiber magnet retention
• Engineered titanium structures

Samarium Cobalt

The elevated temperatures of a vehicle drive train require magnets that can resist demagnetization. Samarium cobalt based magnets, such as Arnold’s RECOMA 35E, maintain full magnetic output at high temperature and also have a low reversible temperature coefficient, making them a smart choice for motor designs.

A typical motor can have an ambient temperature anywhere between -40°C and 125°C. When it’s operating inside a vehicle’s engine bay, temperatures can reach over 180°C, especially during engine soak. The lower reversible temperature coefficient of SmCo magnets results in much flatter operating characteristics across a temperature range. Download the RECOMA 35E data sheet.

Laminated Magnets

When designing a PM motor with a non-conductive retaining sleeve, Joule losses can be a significant loss driver. Laminated magnets can reduce these losses.

Thin Stator Lamination Materials

Arnold’s Precision Thin Metals Division manufactures precision rolled thin gauge metal strip products specifically for high frequency applications. The most applicable material for stator applications would be a 0.005”– 0.007” thick NGOES.  These precision thin materials limit eddy currents, which reduces core losses in the stator, reducing heat and increasing energy efficiency.

Carbon Fiber

Carbon fiber material, such as Arnold’s Wraptite sleeving, offers a superior design alternative for high performance automotive applications in which rotational speeds exceed the capabilities of traditional materials. Carbon fiber materials not only provide additional strength above traditional nonmagnetic stainless steels and inconels, but they also eliminate eddy currents in the containment sleeve, which reduces heat generation and improves efficiency. In addition, Wraptite encapsulation reduces system weight for a better balance, enabling reliable operation in extreme conditions. Download the Wraptite data sheet.

Titanium

Titanium is lightweight and durable under harsh temperature and chemical conditions, making it an ideal material for light weighting applications. Other exceptional characteristics include high overall strength, corrosion resistance, and workability.
Arnold's PTM Division offers titanium products in a number of CP grades and several standard alloy compositions and is Nadcap certified for heat treatment.

For more on transferring aerospace technology to automotive applications, download the full presentation from last month’s Electric & Hybrid Vehicle Technology Expo.