Differential Cutaway

so here's a cutaway of an open differential uh we have the uh input on the front um we got a handle bolted onto it we have my uh two pinion shaft bearings that are are sitting into the housing um these are tapered roller bearings coming from opposing ends here is my crush collar that's positioned in between them and you you can see the the the little bit of a ridge here um what happens when when we we tighten the nut on the end underneath where the uh U joint would normally sit uh it squeezes the two bearings together uh and and and puts a a tension on this uh collapsible collar and it actually will collapse a little bit to adjust its length uh and that is why when we are are putting these together we would normally start with our Crown in opinion assembly or Carrier all out of the way and we would just rotate this to determine how much rolling resistanc there would be and that would be what we refer to as the setting for my uh pinion bearing preload uh we talked a bit about already now then when we add the the the carrier assembly and then we make the adjustments on uh the bearings the side bearings on the back here um that would be what we refer to then as total bearing preload and that in in the case of this uh differential would be how much it effort it takes to rotate the handle while we are all assembled so this differential is a Salsbury style the one we had before was a banel where the carrier and the pinion all came out of it when we unbolted the flange from the front this one has a bolt pattern and cover on located on the back back when we remove this we would have to use a spreader bar and and bolt it into the housing and spread it apart in order to get the bearings out adjustments to the the the bearing uh preload are made through a series of of installing shims uh in between each side of the bearing um when we go to make adjustments on that uh for positioning for backlash or or tooth pattern it would mean uh removing a shim from one side and installing it on the other side once the bearing preload has been set the adjustment of this contact pattern has to do with the setting of The pinion depth and the backlash on the between the crown and pinion gears um I always refer to this as being counterintuitive this adjustment so if we wanted to move this contact pattern closer to the heel and away from the toe it is not the pinion depth but the backlash so if we wanted to move it from here two more out in this area we would increase the backlash which would in the case of this differential which would mean removing a shim from the left hand side and replacing it on the right hand side if the contact was too close to the top of the tooth and we wanted to move it it deeper on the tooth pattern we would set my pinion depth to be a little deeper and I'm going to try and and uh I'll zoom in and hopefully you can uh get a better understanding of what that is so here's the point where my pinion gear is coming into mesh with with my crown gear if I was to push this a little further in this way and I I'll I'll rotate it slowly you can see that where this is coming together it would reach deeper o into that tooth and that is how we move the contact from the top land to the root of the tooth I like to look at it this way where we refer to these as the center line so if you look at the center line of my pinion gear and the center line of my crown so I would um refer to it as as either uh move the pinion towards the center line of the crown gear or move the crown gear towards the center line of the pinion gear or the opposite of that would also be true if you depending on which style of of Correction you would need to make in your contact pattern if my point of contact was too close to the heel of the tooth and I wanted to move it down it first off that would give probably be an indication that I have an excessive amount of backlash by moving the uh Crown gear to the to the right or towards the center line of the pinion that would uh decrease my backlash and move the point of contact closer to the toe so looking at these and I'll I'll give it a couple of rotations so we can uh spread the the marking solution out a little bit and get a a fresh look at this um this is actually a really good pattern right here with this pattern you can see then we're we're about a little over half of the contact on here as our load comes onto the the the differential this contact pattern will spread out and it will get closer to the heel and and and cover the whole uh face of the tooth so here you can see the contact pattern is running pretty much half to 3/4 way along the the face of the tooth um when we put the differential underload uh this contact pattern will actually spread out more and what we are trying to make sure then is by starting it near the bottom and covering this section is that if if I was to start too high on it then what would happen is after it comes under a load the contact between the pinion would start to run off of the the heel of the the tooth and we would be putting more work or harder work on a smaller surface of the tooth when we have a speed change from one side to the other it these spider gears will essentially kind of crawl around the two side gears to transfer any change of of speed from one side to the other if one side and you have to remember this is these are always going to be uh turning in the same direction one side might accelerate slightly and whatever that side accelerates by whatever amount the opposite side would decelerate by the the same amount to keep everything uh driving evenly a quick look at some of the gear styles that are involved in this um first of all these are uh straight bevel gears that we are using in the carrier assembly so my side gears and my pinion or spider gears in here are straight bevel which means that they um work very well um the center line of each of the gears is all on one um plane if you will and so that everything works straight across the this change in that was originally to mount the pinion gear uh of the Spiral bevel um gear in the center line of the uh Crown gear um what they found though was that the uh Center of uh of contact was was too high and by lowering it uh we gained a couple of things first of all by lowering it it means that the tooth uh contact pattern is actually going to be a little longer than if this uh pinion gear was um lined up with the center line of the crown gear when the center line of the pinion gear is located below the center line of the crown gear it's referred to as a Hyo when the center line of the pinion gear is located above the center line of the crown gear it's referred to as an amboid gear

Channel: coaddog

Views: 2,752

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Id: p89qnAA8MBc

Length: 9min 12sec (552 seconds)

Published: Mon Feb 12 2024