Chain Assembly Create an extra part where the relationship ...

testybelchMechanics

Nov 14, 2013 (3 years and 8 months ago)

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Chain Assembly


1.

Create

an extra part where the relationship between the parts
can be stored

(Mating)

Sketch the

chain path and outer limit

Make them selectable objects with Ableiten & Parallel Curve



2.

Bring in Chain link

2xKongruenz



3.

DMU Kinematics


Fix sketch to create mechanism

2xPunktkurvenverbindung



1xGleitkurveverbindung




4.

Bring in 2
nd

link element

2xKongruenz



5.

Change to DMU Kinematics

Insert Revolute Joint between Links


Insert Punktkurvenverbindung



6.

Repeat step 4 & 5

… It may
take a while


Then add the turning of the gears to the Mechanism
:

1.

Draw

the
centre axis of both gears in the

part
“Mating”


2.

Use the
se

axes in DMU Kinematics to create 2 Drehverbindungen


3.

Create a Zahnradverbindung


Find the two required Drehverbindugen from
the
Mechanism Verbindungen


And tick the box

“Abhänginger Winkel fr die Drehverbindung 1 or 2”

Don’t forget the Gear Ratio!





Now to match the Gear to the chain

First go back to the “Mating” Part and draw a
line that is 45⁰ to the coordinate system of the gear.
The gear should be the one that has the “Abhängiger Winkel
für die Drehverbindung” from earlier

Now connect this to the Befehle by right clicking on each
Befehle and selecting “Object Befehle …
-

Defin
ition”. Then
click on Verknüpfen and select the line
. Do this for both
Befehlen

(it will become clear why later)

The mechanism can now be simulated with both the chain and gears moving together using the
“Simulation mit Regeln” Button.


It is located besi
de the Simulation mit Befehlen button

You will notice that the gear speed and the chain speed don’t match. To fix this, right click on the Go
to the Befehle in the Mechanism. There should be two. One for the Chain movement and one for the
rotation. If y
ou check the definition of each Befehle and look at the formula


you will notice that
the formula for rotation is multiplied by 1deg and the one for linear motion of the chain is multiplied
by 1mm. Therefore 1degree of
rotation of the driving gear is take
n as
equivilant to 1mm of motion of the
chain. We know this is however not
the case and in order to find the
correct value, Use the earlier sketch in
“Mating” of the diameter of the
centre of the chain path (what you
you have been telling the middle of
the

chain links to be Kongruent to),
take a 1degree arc of this circle and
measure the absolute distance
between the start and finish of this arc.

In this case it was 0,325mm. Enter this value into the formula from earlier
(Above). Make sure that you change
0,325mm to 0.325mm!

Now the teeth and chain run at the correct speed but they don’t mesh
properly. To fix this simply measure by how much the teeth are out


and
add this value to the formula with + or
-
. Then Finished!!