to understand the terms in mechanical engineering

3. GEAR,S

4. CONTENTS
• Introduction to Gears
•Types of gears
•manufacturing

5. INTRODUCTION TO GEARS
• A toothed wheel that works with
other to alter the relation b/w the
speed of a driving mechanism to
the speed of driven parts.
• A gear is a component within a
transmission device that transmits
rotational force to another gear or device

6. GEAR CLASSIFICATIONS
Gears may be classified according to the relative position of the
axes of revolution. There are three axes.
•parallel,
•intersecting,
•neither parallel nor intersecting.

7. PARALLEL GEARS
• Two parallel and co-planar shafts are connected by
the gear as shown in figure these gears are known as
parallel gears.
• Teeth,s are parallel to the axis of rotation
• The arrangement of these gears is also known
as spur gearing arrangement because these
gears have teeth parallel to the axis of wheel
• Parallel gears are also known as helical gears
because in which the teeth's are inclined to the axis

8. INTERSECTING GEAR
When two bevel gears mesh, their imaginary vertices must occupy the same point. Their
shaft axes also intersect at this point, forming an arbitrary non-straight angle between the
shafts. The angle between the shafts can be anything except zero or 180 degrees. Bevel
gears with equal numbers of teeth and shaft axes at 90 degrees are called intersecting
gears.

9. NEITHER PARALLEL
NOR INTERSECTING
• Those gears that have non-intersecting shafts these gears provide an
effective answer for power transmission applications requiring high ratio
speed reduction a limited space using non-intersecting shafts. neither
parallel nor intersecting
• These are ideal for applications requiring
only limited load capacity

10. NEITHER PARALLEL NOR
INTERSECTING
• Spiral bgenerators (like Gleason, Klingelnberg, Heidenreich & Harbeck, WMW Modul) manufacture bevel
gears with an octoidal tooth profile. IMPORTANT: For 5-axis milled bevel gear sets it is important to
choose the same calculation / layout like the conventional manufacturing method. Simplified calculated
bevel gears on the basis of an equivalent cylindrical gear in normal section with an involute tooth form
show a deviant tooth form with reduced tooth strength by 10-28% without offset and 45% with offset
[Diss. Hünecke, TU Dresden]. Furthermore the "involute bevel gear sets" cause more noise
• evel gears can be manufactured as Gleason types (circular arc with non-constant tooth depth), Oerlikon
and Curvex types (circular arc with constant tooth depth), Klingelnberg Cyclo-Palloid (Epicycloide with
constant tooth depth) or Klingelnberg Palloid. Spiral bevel gears have the same advantages and
disadvantages relative to their straight-cut cousins as helical gears do to spur gears. Straight bevel gears
are generally used only at speeds below 5 m/s (1000 ft/min), or, for small gears, 1000 r.p.m.[13]
• Note: The cylindrical gear tooth profile corresponds to an involute, but the bevel gear tooth profile to an
octoid. All traditional bevel gear

11. GEAR MANUFACTURING
• Gear manufacturing refers to the making of gears. Gears can
be manufactured by a variety of processes, including casting,
forging, extrusion, powder metallurgy, and blanking. As a
general rule, however, machining is applied to achieve the
final dimensions, shape and surface finish in the gear. The
initial operations that produce a semifinishing part ready for
gear machining as referred to as blanking operations; the
starting product in gear machining

12. GEAR GENERATION
• In gear generating, the tooth flanks are obtained as an outline of the
subsequent positions of the cutter, which resembles in shape the mating
gear in the gear pair. There are two machining processes employed
shaping and milling. There are several modifications of these processes
for different cutting tool used.

13. MANUFACTURING GEAR
Blended Powder
Compacted Rigid Tooling
( Powder compacted rigidly)
Pre-sinter
Repress or Coining Re-sinter Gear

14. GEAR SHIPING IN DISC
CUTTER

15. GEAR SHAPING BY END MILL CUTTER
THE END MILL CUTTER SHAPE CONFIRMS THE GEAR TOOTH SHAPE. EACH TOOTH IS CUT AT
TIME AND THEN INDEXED FOR NEXT TOOTH SPACE FOR CUTTING. A SET OF 10 CUTTERS WILL
DO FOR 12 TO 120 TEETH GEARS. SUITED FOR SMALL VOLUME PRODUCTION OF LOW PRECISION
GEARS.

16. TYPES OF GEARS
1. According to the position of axes of the shafts.
a. Parallel
1.Spur Gear
2.Helical Gear
3.Rack and Pinion
b. Intersecting
Bevel Gear
c. Non-intersecting and Non-parallel
worm and worm gears

17. SPUR GEAR
• Teeth is parallel to axis of rotation
• Transmit power from one shaft to another
parallel shaft
• Used in Electric screwdriver, washing
machine and clothes dryer
• External and internal spur gear