Gears Documentation Blog Entry

Hi guysss👋🏻! Welcome back to my blog , hope you missed reading my blog since last week i didnt write any blog🤭. In Week 5 of CPDD, i did a practical lesson on gears where we had to design the gear ratio to raise 0.5-1.5L water with minimum force and also assemble a hand-squeezed fan.

In this page, I will describe:

1. The definition of gear module, pitch circular diameter and the relationship

between gear module, pitch circular diameter and number of teeth.

2.The relationship between gear ratio (speed ratio) and output speed, between

gear ratio and torque for a pair of gears.

3.How I can design a better hand-squeezed fan, including the sketches

4.How my practical team arranged the gears provided in the practical to raise

the water bottle, consisting of:

a.Calculation of the gear ratio (speed ratio)

b.The photo of the actual gear layout.

c.Calculation of the number of revolutions required to rotate the crank

handle.

d.The video of the turning of the gears to lift the water bottle.

5.My Learning reflection on the gears activities.

Lets get started‼️

1. These are the definition of gear module, pitch circular diameter and the relationship between gear module, pitch circular diameter and number of teeth:

Gear module refers to the size of the gear teeth. The unit for module is mm. The larger a module number, the larger is the size of the teeth. Gears that mesh together are having the same module⚙️

Pitch circular diameter is the imaginary circle that passes throguh the contact point between two meshing gears. It represents the diameters of two friction rollers in contact and moves at the same linear velocity📏.

The relationship between module(m), pitch circular diameter(PCD) and number of teeth(z) is m=PCD/Z , M is inversely proportional to Z but directly proportional to PCD. 2. Below is the relationship between gear ratio (speed ratio) and output speed for a pair of gears.

When gear ratio increase, output speed decrease. Gear ratio is inversely proportional to output speed. Gear ratio = torque/ output speed Below is the relationship between gear ratio and torque for a pair of gears.

When gear ratio increase, torque increase. Gear ratio is directly proportional torque. The gear ratio also expresses the ratio of the output torque to the input torque.

3. Below are the proposed design to make the hand-squeezed fan better:

Since it is made using 3d printing, in order to achieve a better fan, this has to be done to ensure a smoother surface to ease the rotation of the gears;

• Sanding

• Bead bleating

• vapor smoothing

• Ensure that the input and output are one big and one small to increase the power of a turning force

Sketch of gears:

Gear ratio:

actual gear:

Slow-motion of our fan when being hand-squeezed:

4. Below are the description on how my practical team arranged the gears provided in the practical to raise the water bottle.

a.Calculation of the gear ratio (speed ratio), including sketch.

Sketch:

b.The photo of the actual gear layout.

c.Calculation of the number of revolutions required to rotate the crank handle.

d.The video of the turning of the gears to lift the water bottle.

5. Below is my Learning Reflection on the gears activities

During this practical, the first thing we were tasked to complete was the theory worksheet. While doing the worksheet, my team split up the questions given in order to complete it faster however our group finished the worksheet last as compared to other groups🥲. Looking up for the answers on google is not an easy task as i did not know which source is accurate and reliable. Different websites will state different answers🧐. My team ensured that we find the most accurate answer as the worksheet is going to be used to help us with our quiz at the end of the practical📚.

After completing the worksheet, we then moved on to activity 1 where we had to design the gear ratio to raise 0.5-1.5L water with minimum force. Firstly, we had to figure out the gear sequence in order to achieve he highest possible gear ratio. To me, this was the most challenging part of the whole practical🥵🥵. At first, my group tried numerous times , to position the gears accordingly and calculate the gear ratio however we could not get above 20😭. When other teams shared that the answer is 26.8, me and my team members were frustrated that we could not figure it out😩😤. However, we did not give up and kept trying , eventually we did it, yayy😁. The trick was to put bigger output & smaller input.

Since there was not much time left, we split up the work ; Asraf and valarie assemble the gears on the board using the screws while me and eshvin start on activity 2. Activity 2 was where we had to make the hand-squeezed fan. Me and eshvin assemble it together. At first, we were a little lost on how that device works however we figured it out after putting the gears inside. I found it very cool how one could make a fan by purely using 3d printing🤯🤯. In a nutshell, i enjoyed this practical as it was fun and interesting to see how gears operate🤓🤪. However, it can be quite a hassle to work with gears🫠.

Thats all for this week's blog! Stay tuned for my next oneee😎🤙🏻