Shrink Fitting A Gear to a Shaft

Objective

To heat a steel gear to 500 ºF (260 ºC) for a shrink fitting application

End Product

gear

Equipment

Ambrell EASYHEAT 0224 2kW, 150-400 kHz induction heating system equipped with a remote heat station containing two 0.17 μF capacitors

A single position two-turn helical coil designed and developed for this application

Materials

Customer supplied steel gear & steel shaft

Temperature

500 ºF (260 ºC)

Frequency

304 kHz

Testing

The part was placed into the helical coil on top of a ceramic cylinder. The ceramic cylinder had a hole in it with a depth of approximate 24 mm (2.4 cm). The induction power was turned on. After 30 seconds the gear heated to temperature.

The shaft was then inserted into the part and the bottom of the ceramic cylinder acted like a stop and positioned the shaft to the correct height. The parts were then allowed to cool.

Benefits

• Part quality: The customer was using a torch, which can lead to inconsistent part quality. Conversely, induction is highly repeatable
• Speed: The gear heated to temperature within 30 seconds, which is an improvement for the client
• Repeatability: Induction’s fast, precise heating means the client can count on consistent results once it is implemented into their process

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