Info about cdj 2000nxs jogwheel

Hi guys, this is my first post on this forum. I am going to build a cdj from scratch, so I was looking for something usefull to build a jog wheel. I was watching videos on youtube like disassembling of the jogwheel so I noticed that there were springs under a white ring with some little wheels.
Can you give me an explanation about this springs and about the way the jogwheel works? And how the hardness of the spin is realized in hardware?
Thanks :)

P.S. I hope I've chose the right section of the right forum to make this question.