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Why electric motors should be assembled bonding.

Why Electric Motors Should Be Assembled by Bonding

by:
September 07, 2016

Electric motors are omnipresent in everyday life. Through technological advancements, they have become smaller and more efficient, creating new challenges for joining technology. Bonding provides numerous advantages in terms of production and operation, allowing engineers designing motors to choose from a wide range of adhesives.

Tesla has been instrumental in establishing electric cars as an ideal solution for efficient and sustainable mobility of the future. However, electric motors are not only used for emission-free driving, they are also found in window regulators and seat adjusters. In fact, they can be found everywhere — in electric bikes, in tools, even in our kitchens.

All manufacturers of electric motors have one common goal in mind: making them smaller and more powerful, while increasing their efficiency. In the effort to achieve this goal, engineers must consider many things; for example, the lamination design, an optimal embedding of the magnets into the lamination stack, and leaving the smallest gap possible between magnet and coil.

Better Joining with Adhesives

Established methods of joining, like mechanical clamping or bandaging of magnets, are reaching their limits in terms of both motor function and production process. For example, a progressive reduction in motor size leads to tightened manufacturing tolerances, which drives up costs. Manufacturers of efficient electric motors rely more and more on rare earth magnets. Since they are prone to corrosion, their surfaces are treated with a coating in the form of passivation, nickel plating, or epoxy resin plating. This coating may be damaged during assembly, openly exposing the magnets to direct environmental influences.

Compared to these conventional methods, bonding offers many advantages. It is a particularly suitable option for three steps in the assembly of electric motors: joining magnets and lamination stacks, joining shaft and rotor, and joining stator and housing.

Adhesives not only compensate for higher manufacturing tolerances and prevent fretting corrosion or contact corrosion, but also provide impact resistance, which is essential to withstand the high dynamic forces of electric motors. Their vibration-damping characteristics reduce noise and provide acoustic improvement. Thanks to the fact that they distribute stress homogeneously, adhesives can compensate for thermal stress that may be generated due to different coefficients of thermal expansion between stator and housing. Their gap-filling properties help prevent slippage and play in the area of the shaft.

Bonding often helps reduce production costs. It allows manufacturers to expand the tolerances of components, enables easy and efficient automation, and can be used without heat input.

Apart from these structural connections, the automotive industry additionally uses adhesives for encapsulating sensitive components in electric motors to protect them from humidity, aggressive media, and mechanical stress. They provide vibration protection to the coil wire, corrosion protection to solder and welded contacts, and they protect the coil

from contact with abrasive materials.

Selecting the Appropriate Adhesive

Given the variety of sizes of electric motors and the different environmental conditions they are exposed to, there is no single blueprint for a universal design or a standard production process. Nevertheless, it is advisable to start by examining the strong and weak points of the major adhesive groups, and then perform tests with individual products and components.

Although acrylates and polyurethanes do have their place, they are less suited for high-end applications because of their moderate reliability. This leaves three product groups to consider: metal adhesives, one-component epoxy resins, and two-component epoxy resins. All have a good bond strength and impact resistance, but these three product groups partly differ in their degree of universal adhesion, temperature stability, and gap-filling capacity capabilities. In manufacturing processes, these products groups have notable differences in their need for mixing, flowability, light-fixation possibility, curing time, and their need for heat curing.

As motors become smaller and more powerful, adhesive bonding gains in popularity, and the variety of materials and surfaces it can be used on expands, more and more engineers are likely to consider using it for their applications.

Dr. Karl Bitzer is head of product management at DELO Industrial Adhesives. Before joining DELO, Bitzer worked at Siemens, holding positions in product management and business development.

A noncommissioned officer with Troop C, 1st Squadron, 32nd Cavalary Regiment, prepares to lower the American flag during a transfer of authority ceremony at Observation Post Mace, as U.S. and Afghan National Army Soldiers look on. The ANA assumed control of OP Mace from the U.S. Army on Dec. 20. OP Mace is the northernmost observation post in Afghanistan’s Kunar Province, which borders Pakistan. It is the first significant installation in the province for which ANA forces have assumed complete responsibility. ANA soldiers now safeguard the post and surrounding area, in accordance with the way ahead laid out in the Lisbon Plan to transfer security responsibility to Afghan forces. (U.S. Air Force Photo by Capt. Peter Shinn, Task Force Bastogne Public Affairs/RELEASED)

DANCO Thanks our past, current, and future veterans. Lets all take the time to thank a veteran and reflect on the sacrifices theses fine men, women, and families have endured to maintain the freedoms we hold dear.

One of the firsts…EV1 Electric Car

 

EV1 Electric Car

EV1 Electric Car
Note: The EV1 will be moving to American on the Move on January 19, 2016.
CREATING CHANGE
Creating a modern electric car demonstrated the differences between invention and innovation, and the challenges of each process. Invention is the development of a new idea. Innovation is bringing the idea to market and convincing society to adopt the technology.
The EV1 was the first modern electric car designed for a mass market. Beginning in 1996, General Motors built 1,117 of the cars and leased most of them to consumers in California, Arizona, and Georgia. The EV1 became the focal point of a national discussion about innovation and the promise of reducing air pollution and dependence on oil with electric cars.
In 1990 the California Air Resources Board required automakers to offer emission-free vehicles by 1998. The EV1’s aerodynamic shape and advanced power management systems, developed by human- and solar-powered aircraft innovator Paul MacCready, AeroVironment Inc., and GM Electric Vehicles, made the new car practical, energy efficient, and appealing to consumers. But in 2003 GM abruptly canceled the EV1 program, citing high production costs and a small market.
Citizen protests over the EV1’s termination reflected public demand for energy reform. Concerns about air pollution and climate change, and interest in lower energy cost per mile and appealing drive qualities, created a market for electric cars. In 2010 GM began selling the Chevrolet Volt, a hybrid car with a gasoline-charged electric motor. The all-electric Nissan LEAF, Tesla Model S, Ford Focus Electric, and Chevrolet Spark EV expanded energy choice while eliminating tailpipe emissions.
Gift of General Motors Corporation

What’s inside
The EV1 combined advanced propulsion controls with power options and passenger amenities. Its quick acceleration, clean and quiet drive, and low maintenance also appealed to consumers in a lease program.
Diagram of EV1 courtesy of General Motors Corporation