CHAPTER 20GEARING AND CAMS

INSTRUCTOR: M.YAQUB

ME 210: Gear: week#13

20.1 Gears

• Gears are used to transmit power and rotating or reciprocating motion from one machine part to another.

• Few gears are given in the next slide.

ME 210: Gear: week#13

ME 210: Gear: week#13

20.2 Spur Gear (For Parallel shaft)• A friction wheel can be used to transmit

power from one shaft to anther parallel shaft.

• It may have slip and a large pressure is required to avoid the slip.

• If teeth are provided on the surface, pressure can be reduces and no slip. It become a spur gear.

ME 210: Gear: week#13

ME 210: Gear: week#13

• Linear velocity = (pi) D n, it must be same for both gear to avoid relative motion.

• Hence

ME 210: Gear: week#13

ME 210: Gear: week#13

ME 210: Gear: week#13

SPUR GEAR

ME 210: Gear: week#13

ME 210: Gear: week#13

20.4 The shape of the tooth

• For minimum noise and smooth operation, the curved surface of the tooth profile must be a definite geometric form, the most common is involute profile.

• Pressure angle is important usually two pressure angle, 14.5 and 20 degree.

ME 210: Gear: week#13

How to construct a base circle

ME 210: Gear: week#13

ME 210: Gear: week#13

ME 210: Gear: week#13

ME 210: Gear: week#13

Worm Gear

For non parallel and non intersecting shaft

ME 210: Gear: week#13

ME 210: Gear: week#13

Bevel Gear (For intersecting shaft)

ME 210: Gear: week#13

ME 210: Gear: week#13

ME 210: Gear: week#13