TECHNOLOGICAL DESIGN ENGINEERING 1: CALCULATIONS

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donderdag 27 januari 2011

GEARBOX EFFICIENCY CALCULATION

The engine: I didn't find the rpm of the motor, so I will use the rpm of a simular engine I found here http://www2.conrad.be/goto.php?artikel=129024

550Watt
1500 rpm

The energy conversion efficiency of a gear is 98% (this is a mean value by experience)

The Formulas

The efficiency of the gearbox is 88,58%

The max torque is 233 Nm

The max Force is 3740 N

Every axis has his own speed, torque and force.

#The blender needs a high speed, less torque and force

#A mill, needs a low speed, high torque and force

woensdag 26 januari 2011

TORSION SPRING - CALCULATION OF THE SPRING FORCE

Now we will do some calculations on the torsion spring in the body of the mixer.
The spring has the function to help the user to lift up the top part of the mixer. Then the user needs to use a force to click back the top part in the other part.
We will calculate the force need to put the top part down.

So, you will need a force of 70.92N or a mass of 7.23 kg to put the top part down.

The E modulus is found in the next pdf, I used the steanless steel wire (193*10^9 Pa)

http://www.tribology-abc.com/calculators/properties_of_common_spring_materials.pdf

A control of the calculation:

http://www.tribology-abc.com/calculators/t14_4.htm

CALCULATION OF THE SPRING CONSTANT

The calculation is about this spring. It's part 17 in the picture.
The spring is necessary for a push button.

The preparation for the calculation, the spring and a bottle of water (1.5L)

Length spring at rest= 18.0mm
Length spring with the weight= 25.0mm
so delta l = 25.0-18.0= 7mm = 0.007m

We use 'the Law of Hook'

k=F/Delta l

k=the spring constant (N/m)
F=the weight of the bottle of water= 1.5kg => 9.81(N/kg) * 1.5 (kg) = 14.715 N

so k=14.715/0.007 = 2102.14 N/m