Shrink Fitting Cam Shaft Gears

Objective

To heat aluminum and steel camshaft gears to over 500°F within 4 minutes for a shrink fitting application.

End Product

camshaft gears

Equipment

Ambrell 5 kW power supply, remote heat station with one 0.66 μF capacitor and a specially designed induction coil.

Materials

6” diameter, 2” thick steel and aluminum camshaft gears, “K” type thermocouple, digital thermometer

Temperature

518° F for the steel gear; 320°F for the aluminum gear

Frequency

151 kHz for the steel gear; 158 kHz for the aluminum gear

Testing

Best results were achieved with the 3.5 kW power supply. Heating times of 3 minutes for the steel gear and 4 minutes for the aluminum gear resulted in uniform expansion of the gears for effective shrink fitting. The shafts dropped easily into the gears after the heat cycle.

Benefits

The shafts were gripped tightly after 30 seconds, resulting in total heat cycle times of 3.5 minutes for steel and 4.5 minutes for aluminum.

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