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  1. robindbois

    Noise is not the same in both direction

    I was wondering waht is the standard method to deburr a plastic gear that was cutted? I can see small burrs on the profile where the cutter exited. The noise is at the pinion frequency and the slip ratio at sap for the pinion is 2.67, which is quite high. How can I modify the tip to lower...
  2. robindbois

    Extreme pitting on an unhardened pinion, need help

    Gear can go in both direction and have the load always in the same direction. Is the pitting on the loaded side?
  3. robindbois

    Noise is not the same in both direction

    Ralph2, I have the noise with the straight gear set. I haven't received the helical internal gear yet but should be in a couple of day. I just found one place in north america that can cut it! I've asked around 25 places! Diamondjim, As you said, the plastic set is quieter and I'm happy to...
  4. robindbois

    Noise is not the same in both direction

    I calculated the minimum number of teeth under undercutting and pointing criteria. This is why I went to a shifting of the profile by 50% I used the fairfield program and a formula found on an university site teaching gear theory. I do not have any place to have multistage and I'm under tight...
  5. robindbois

    Noise is not the same in both direction

    DiamonJim, what you said make sense, from the fairfield run, I have a slip ratio at sap on the pinion of -2.68 which I think is relativery high (from afairfield guy it should be less than 2 and ideally less than 1) which lead to a more susceptible system to noise mesh. Probably this fact is...
  6. robindbois

    Noise is not the same in both direction

    Vibegeek, What you said make sense but I did not know that it can make a practical difference in moise and life. By having an even and uneven number of teeth in gears, you alternate the mesh pair of toth on pinion and gear. In this way, you wear the teethin a more equal pattern, avoiding...
  7. robindbois

    Noise is not the same in both direction

    Its impossible to turn any of the gears. I have two ss pinion, 2 aluminum internal gears and two plastic internal gears. I have the noise in the same direction with all combinations. However, the system is quieter when driving it by the pinion with the motor than driving it with the internal...
  8. robindbois

    Noise is not the same in both direction

    I talked to the cutter guy and he told me that the internal gears are cutted with a shaper. Since it is an internal small gear it cannot be generated by any rotating tooling. I installed the set with a plastic internal gear and started a run to see if I could have any break-in effect that...
  9. robindbois

    Starting Torqure et. al.

    Hi again! Following the previous reply, the friction force is, in theory, indepentent of the surface area. It is F=uN where the force you can apply tangetial to the roll (F) is dependant to the normal force (N) and a friction coefficient. This force F os the furce you'll use to calculate...
  10. robindbois

    Noise is not the same in both direction

    I don't have the device here, I'm the only mech eng working in an electronic enterprise... Should I be able to see a difference by eye or by passing a needle on both surface and feel it?
  11. robindbois

    Starting Torqure et. al.

    You must calculate the inertia of your system and find in how much time you want the motor to get to the speed you want. This is basically the same formula as F=MA (Newton's law) but in a rotationnal system. This is an approximation that does not take friction into account but friction must be...
  12. robindbois

    Noise is not the same in both direction

    A couple of month ago I started a topic concerning a set of a small pinion and an internal gear assembles in parallel axis. I had to explore many setting in order to reduce noise. There is almost no load to transfert. Choice was to use plastic internal gear so I made one in 6061 and another...
  13. robindbois

    Interference equation valid for internal gear?

    Ok, after a while of playing with the software and good advice from diamondjm I went to that final design: This is a pair composed of a small pinion and an internal gear: (Fairfield run is available on request) DP: 48 pressure angle: 20 Helix angle: 30 (right angle) Pinion: 12 teeth...
  14. robindbois

    different addendum offset raise backlash???

    thinking about my question, I think I got the answer. The backlash won't change since when you offset the rack, the circular thickness changes at the pitch diameter. Hum, I'm going to check this with the Fairfield program...
  15. robindbois

    different addendum offset raise backlash???

    If I have a pair of mating gear with differant addendum offset (one with 50% offset and the other without offset), will I have an higher backlash that if I where using no offset at all?? (suppose I use theorical center distance modifiad for the offset) Robin
  16. robindbois

    Interference equation valid for internal gear?

    There is no space to put any reducer (and no space outside the internal gear). The design is going to be a single helical internal gear with a small pinion driving it (then from the inside). The only unwnowns are the paramaters of the gears to meet the requirement I wrote in a previous post...
  17. robindbois

    Interference equation valid for internal gear?

    Pardal, I do not have space outside the turning internal gear so the driving device must be inside. Robin
  18. robindbois

    Interference equation valid for internal gear?

    I did a couple of run and 48 of pitch could be used. Pinion and internal gear: pressure angle 20, helix angle 30, diametral normal pitch of 48, no addendum or dedendum modification. pinion: 12 teeth internal gear of 210 teeth From the run, I do not have any sap problem and slip ratio are...
  19. robindbois

    Interference equation valid for internal gear?

    I forgot to mention that the 5" pitch diameter is transverse, not normal.
  20. robindbois

    Interference equation valid for internal gear?

    What does SAP stand for?? Yes, I started by extending the addendum and shortening the dedendum. I enterned the datas like you; adendum/dedendum modification and backlash. Did you say that extended addendum will run qiter? Why? I'm not limited to 64 pitch (me too found it really small) but...

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