Gears

GEARS

Hello welcome back to my BLOG!! 😁 This blog entry is all about gears and how i was taught from how it works to applying it in my practical session

 There are various types of gears but today i will only be talking about traditional gears like the one in the picture above

Definition of gear module [m]:

The gear module refers to the size of the gear teeth so larger the gear module = larger gear teeth size

Unit: [mm]

Pitch circular diameter [PCD]:

The pitch diameter refers to the imaginary circle that passes through the contact point between two meshing gears

Unit: [mm]

relationship between Gear module, pitch circular diameter and number of teeth

Number of teeth: Z

Relationship between gear ratio (speed ratio) and output speed for a pair of gears

input speed/output speed = Gear ratio

instead of the usual formula for gear ratio (output/input), the formula is inverted when calculating speed. This is because for a higher gear ratio, the follower gear would be bigger than the driver gear but this also means the driver gear would turn more =  higher speed

therefore if we use the normal formula, the calculated gear ratio would be smaller than the actual gear ratio so we have to invert the formula to get the actual gear ratio

Relationship between gear ratio and torque for a pair of gears

Output torque/input torque = Gear ratio

Proposed design to make the hand-squeezed fan better

The picture above is the sketch of the proposed design to make the fan spin as much as what we think possible. Also as seen on the sketch above, the calculated gear ratio for this design is 0.10125 so this means that the fan would spin 10 times when the crank turns once.

The video above is our proposed fan design spinning 

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

a) calculation of gear 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 gears to lift the water bottle

Learning reflection

 

In this practical session, I learnt how to apply my knowledge of gears into actual hands-on work and I think there are a few big lessons to learn from this.

The first problem was that we should have been more prepared before conducting this practical.

Although there was no requirement to brainstorm about the line-up of the gears for activity 1, I feel that we should have done it either ways as 45mins to brainstorm, come up with the most ideal solution and implement the idea was definitely not enough time for my group to show our fullest potential. 

Most of us in the group were learning along the way on how gears ACTUALLY work because when we were doing activity 1, we could not decide on whether the gear ratio should be more than or less than 1. But we eventually figured it out and things smarted to smoothen out.

Our calculations for the number of revolutions were also more than the actual number of revolutions needed but this was most likely due to our poor time management and we had to rush through our workings so that we can submit on time.

Another problem that we faced was that the screw was not aligned properly and was stuck in one of the gear teeth, preventing the gears from turning. We took a good 10 minutes to figure this out because we were trying to find the problem by only looking at the gears from an 'above' angle. This made me realise that i should look at a problem from different perspectives so that i can have more options.

However in activity 2, things went much smoother because we understood how gears work and we managed to figure out a solution for it relatively quickly.

Overall this made me realise that our group lacks chemistry and efficiency because i feel that everyone in my group is individually reliable and dependable but sometimes our thoughts clash and we want to do different things so i would most definitely want to work on building our teamwork throughout this module duration.