(Q)
What is "Center distance"?
(Ans) The center distance is defined the distance which is
between the center of the shaft of a gear to the corresponding center of
shaft of the other gear. Points to note here:
- backlash is related inseparably to the center distance.
- a positive deviation that is permissible of a center distance indicates a
larger backlash, while a negative permissible deviation of a center distance
corresponds to a smaller backlash.
(Q) What is "Shaft angle"?
(Ans) Gears with intersecting axes(bevel gears), and
nonparallel and non intersecting axes gears (like worm gear pair and screw
gears) is connected from one shaft to the other. The shaft angle is
basically, the angle formed by these two shafts. The angle is normally a
right angle. It is vital to Set up the shaft angle precisely as per
specifications because it affects the backlash and tooth contact.
(Q)What is Crowning?
(Ans) Crowning means the removal of a small matter of a
tooth from the center on out to reach toward the edge. It makes the tooth
surface a bit convex. This method makes the gear to remain in touch with the
central region of the tooth and ensures that there is no edge contact. The
more the amount of crowning, less is the quantum of tooth surface contact.
(Q)Which type of gears are perfect for high
speed rotation?
(Ans) The gears which are strong to withstand rotations of
high speed rotation can be used. Other than that the quiet gears are also
quite o.k.
(Q)What is "Zerol Bevel Gear"?
(Ans) Zerol bevel gear is an unique type of spiral bevel
gear. It is essentially a spiral bevel that has zero degree of a spiral
angle tooth advance. It displays the features of both straight and spiral
bevel gears.
(Q)Is there any way to manipulate backlash to
a minimum?
(Ans) Tapered Racks, pinions and Duplex Worms or Worm
wheels can control backlash a bit. However it is not recommended to adjust
the backlash at zero.
(Q)What is a ratio?
(Ans) In case of gears, a ratio refers to gear ratio which
is defined as the ratio of the number of teeth on a pinion to the number of
teeth found on a
ring gear.
(Q)What is the way to express the size of
gear?
(Ans) The units that are used for expressing a gear size
are module (metric) and DP (Eng).
(Q)What are the different methods available
to improve gear precision?
(Ans) In case of cylindrical gears, methods like gear
grinding, shaving or direct cutting are used. In case of bevel gears, gear
grinding and CBN gear grinding are typically used.
(Q)What is the full form of HRH?
(Ans) HRH means high ratio hypoid gears, which in essence
means gears that a gear ratio more than 1/10.
(Q) What is the difference in terms of
efficiency between forward and reverse rotation?
(Ans) There are a few minor areas of difference depending
on a particular gear in question. However, a pinion efficiency drops by
approximately 2 to 3% while on a counterclockwise rotation.
(Q)What are the most crucial factors that
determines the lead time need to produce a gear?
(Ans) Following are the factors(i) material lead time,
especially if it is forged,(ii) lead time on cutting tools.
(Q)While choosing gears based on use, what is
to be considered, the bending strength or the surface durability?
(Ans) It is recommended to consider both bending strength
and surface durability. However, in some exceptional cases the bending
strength is more vital. Such cases are: i) the frequency of gear use is
limited ii) gears are manually operated without the help of electricity iii)
Gears are meshed at low speeds. The final decision has to be taken by the
design engineer.
(Q)What is a Module?
(Ans) Module is basically the unit of size that speaks
about how large or small a gear is. The module is actually the length of
pitch diameter/ tooth. For representing tooth size CP and DP can also be
used. CP = circular pitch, DP= diametral pitch
(Q)Why helical gear reducer should be used?
(Ans) Helical Gears are very efficient and adept in handling higher OHLs. In-Line reducers are more over less costly than conventional parallel shaft.
(Q)Why use bevel gearbox?
(Ans) A bevel gearbox offers a right angle gear solution.
It has a higher efficiency is much higher than the
worm gear. If you need a right angle solution with a low ratio the bevel gear is the right choice.
(Q)What are primary causes of premature gear
reducer failure?
(Ans) Some of the most common causes for premature failure
of a reducer include improper selection for the application, changing the
motor horsepower or speed, incorrect alignment of couplings, improper or
insufficient lubrication, and lack of regular maintenance.
