Chain
Chain Construction
Chains have a surprising number
of parts. The roller turns freely on the bushing,
which is attached on each end to the inner plate. A pin passes
through the bushing, and is attached at each end to the outer plate.
Bicycle chains omit the bushing, instead using the circular ridge formed around
the pin hole of the inner plate.
Chain Dimensions
Chain types are identified by
number; ie. a number 40 chain. The rightmost digit is 0 for chain of the
standard dimensions; 1 for lightweight chain; and 5 for rollerless bushing
chain. The digits to the left indicate the pitch of the chain in
eighths of an inch. For example, a number 40 chain would have a pitch of
four-eighths of an inch, or 1/2", and would be of the standard dimensions
in width, roller diameter, etc.
The roller diameter is
"nearest binary fraction" (32nd of an inch) to 5/8ths of the pitch;
pin diameter is half of roller diameter. The width of the chain, for
"standard" (0 series) chain, is the nearest binary fraction to 5/8ths
of the pitch; for narrow chains (1 series) width is 41% of the pitch. Sprocket
thickness is approximately 85-90% of the roller width.
Plate thickness is 1/8th of the
pitch, except "extra-heavy" chain, which is designated by the suffix
H, and is 1/32" thicker
ANSI
Standard Chain Dimensions
|
Chain No. |
Pitch |
Roller Diameter |
Roller Width |
Sprocket
thickness |
Working Load |
|
25 |
1/4" |
0.130" |
1/8" |
0.110" |
140 lbs |
|
35 |
3/8" |
0.200" |
3/16" |
0.168" |
480 lbs |
|
40 |
1/2" |
5/16" |
5/16" |
0.284" |
810 lbs |
|
41 |
1/2" |
0.306" |
1/4" |
0.227" |
500 lbs |
|
50 |
5/8" |
0.400" |
3/8" |
0.343" |
1400 lbs |
|
60 |
3/4" |
15/32" |
1/2" |
0.459" |
1950 lbs |
|
80 |
1" |
5/8" |
5/8" |
0.575" |
3300 lbs |
Bicycle
and Motorcycle Chain Dimensions
|
Chain No. |
Pitch |
Roller Diameter |
Roller Width |
Sprocket
thickness |
|
Bicycle, with
Derailleur |
1/2" |
5/16" |
1/8" |
0.110" |
|
Bicycle, without
Derailleur |
1/2" |
5/16" |
3/32" |
0.084" |
|
420 |
1/2" |
5/16" |
1/4" |
0.227" |
|
425 |
1/2" |
5/16" |
5/16" |
0.284" |
|
428 |
1/2" |
0.335" |
5/16" |
0.284" |
|
520 |
5/8" |
0.400" |
1/4" |
0.227" |
|
525 |
5/8" |
0.400" |
5/16" |
0.284" |
|
530 |
5/8" |
0.400" |
3/8" |
0.343" |
|
630 |
3/4" |
15/32" |
3/8" |
0.343" |
Selecting a Chain
Two
factors determine the selection of a chain; the working load and the rpm of the
smaller sprocket. The working load sets a lower limit on pitch, and the speed
sets an upper limit.
Maximum Pitch = (900 ÷ rpm ) 2/3
The smaller the pitch, the less noise, wear, and mechanical
losses will be experienced.
Sprockets
There are four types of sprocket;
- Type A: Plain Plate sprockets
- Type B: Hub on one side
- Type C: Hub on both sides
- Type D: Detachable hub
Sprockets should be as large as
possible given the application. The larger a sprocket is, the less the working
load for a given amount of transmitted power, allowing the use of a
smaller-pitch chain. However, chain speeds should be kept under 1200 feet per
minute.
The dimensions of a sprocket can be
calculated as follows, where P is the pitch of the chain, and N is the number
of teeth on the sprocket;
Pitch
Diameter = P ÷ sin (180° ÷ N)
Outside
Diameter = P × (0.6 + cot ( 180° ÷ N) )
Sprocket
thickness = 0.93 × Roller Width - 0.006"
Procedure
for Laying Out a Sprocket
The first thing you need to know to
lay out a sprocket is the dimensions of the chain which is to run upon it,
specifically the pitch, roller diameter, and the roller
width of the chain. The second thing you need to know is the number of
teeth in the sprocket, which will depend entirely on your application. From
these numbers, the outside diameter and thickness of the required blank can be
calculated.
You'll also need to know the angle
between teeth - this is simply the 360° divided by the number of teeth.
The sprocket teeth are
usually truncated one chain pitch above the bottom of the seat; this is not
shown here. Note that this shape is not the only one that will work - bicycles
in particular use various tooth shapes for different circumstances.
Application
Sprockets should be
accurately aligned in a common vertical plane, with their axes parallel. Chain
should be kept clean and well lubricated with a thin, light-bodied oil that
will penetrate the small clearances between pins and bushings.
Center distance should
not be less than 1.5 times the diameter of the larger sprocket, nor less than
30 times the chain pitch, and should not exceed 60 times the chain pitch.
Center distance should be adjustable - one chain pitch is sufficient - and
failing this an idler sprocket should be used to adjust tension. A little slack
is desirable, preferably on the bottom side of the drive.
The chain should wrap at
least 120° around the drive sprocket, which requires a ratio of no more than
3.5 to 1; for greater ratios, an idler sprocket may be required to increase
wrap angle
Now from the above given data and pre requisite knowledge the OEM sprocket of engine side will be of 18 teeth so the differential sprocket pitch need to be same of the engine sprocket and the chain pitch will also be same so that all three will be in a perfect sync and no slippage otherwise due to high tension chain will get broken and due to more slack chain will be slip out
So for the standard OEM internal sprocket the same pitch
ANSI roller chain is used with the 102 Pitch
the data for selected chain is
Chain
No. Pitch Roller
Diameter Roller Width
530
5/8" 0.400"
3/8"
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