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Best Commanders Tank W Europe : Jan - Nov 44.

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  • Originally posted by cbo View Post
    That would be one way of doing it.

    But the Germans seems to have preferred planetary gears as they used in the Panzer IV and the Tiger. And the problem the faced was that they did not have production capacity for more planetary gears, so they went with straight gears made with a very strong alloy - which they then learned they did not have the materials for. At least that is Spielbergers explanation.

    Your reply makes one wonder how the Panther would've fared with a herringbone gear final drive. It might have been more time consuming to make, but my have been the better option given the available production capacity and alloys?
    The Sherman did not brake its tracks for turning as the Panther did for narrow turns, so the forces working on the final drive may have been too great even for the herringbone solution?
    We'll never know for sure CBO, but conventional wisdom says that herringbone drive would have coped with the force, this is what all current heavy usage gearing use and there's no reason to assume the Panther would have been any different.
    In effect the herringbone teeth simply extend the contact surface of the gearing without increasing the diameter or width, rather ingenious really.
    Difficult to machine but very effective.
    This is why M.A.N decided to do without.............Bloody fools!
    All the best mate.

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    • Fascinating thread. I swayed several times and then decided to go with the Sherman. Good combination of quantity and quality. I think a commander would want that combination.

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      • Originally posted by Hanov View Post
        I always thought the Tiger used herringbone final Drives.
        And, iirc, it was intended to use herringbone Drives in the Panther.
        Afaik the only reason for not using them was that the Germany lacked the Tools/production capacity.
        No, there is no herringbone gears in the Tiger final drive. It is all straight gears, but used in a planetary configuration (see below).

        I've never seen herringbone gears mentioned in relation to the Panther either. According to Speilberger, the proposed type was an "Umlaufgetriebe" - planetary gear - that worked fine.

        I'm wondering whether this confusion with the herringbone gears come from a translation error somewhere? They are two rather different things, after all (See below).

        Tiger I final drive:


        Sherman differential, brakes and final drive:

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        • Originally posted by cbo View Post
          No, there is no herringbone gears in the Tiger final drive. It is all straight gears, but used in a planetary configuration (see below).

          I've never seen herringbone gears mentioned in relation to the Panther either. According to Speilberger, the proposed type was an "Umlaufgetriebe" - planetary gear - that worked fine.

          I'm wondering whether this confusion with the herringbone gears come from a translation error somewhere? They are two rather different things, after all (See below).

          Tiger I final drive:


          Sherman differential, brakes and final drive:
          Yes, that's what I recall also.
          "England expects that every man will do his duty!" (English crew members had better get ready for a tough fight against the combined French and Spanish fleets because that's what England expects! However, Scotland, Wales and Ireland appear to expect nothing so the Scottish, Welsh and Irish crew members can relax below decks if they like!)

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          • Here's a simple, using mostly pictures, discussion on the advantages of helical (herringbone) gears over straight cut spur gears like the Germans used.

            http://engr.bd.psu.edu/rxm61/MET210/...licalgears.pdf

            Or this summary:

            Advantages of helical gear As we have discussed in our previous post that in case of helical gear, engagement of helical gear teeth will be gradual and engagement will start from one end of a tooth of helical gear with the other tooth of mating helical gear and spread continuously throughout the tooth as gear rotates. Such gradual engagement of helical gear will provide the silent and smooth operation. Helical gears are preferred for heavy load applications Helical gears could be used to transmit the motion and power between two parallel shafts and also between two non parallel shafts. Helical gears will have more capability to transmit load between two parallel shafts as compared to similar module and equivalent width of spur gears. There will be less wear and tear in case of helical gear during operation as compared to wear and tear in case spur gears operation as if we consider helical gears operation, load will be distributed between several teeth at any time and that is why there will be less wear and tear in operation of helical gears.

            Disadvantages of helical gear

            When a pair of helical gear meshes with each other, there will be creation of axial thrust load on gear due to helix angle of gear teeth and therefore gearbox designer has to select such bearings those are able to absorb and support this axial thrust load.
            There will be sliding movement between mating gear teeth in case of helical gear and heat generation will be more as compared to spur gear application. Therefore helical gear requires good quality of lubrication.
            One pair of mating helical gear will have less efficiency as compared to efficiency of mating spur gears of similar size.
            Power loss in case of helical gear train operation will be more as compared to spur gear train operation.
            Manufacturing and designing cost of helical gears will be more as compared to spur gear designing and manufacturing cost.
            http://www.hkdivedi.com/2015/12/adva...tages-and.html

            The reason the Sherman has a double set of opposed helical gears is to cancel the torque that occurs from them. This force is equal and opposite with two opposite cut gears.

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            • Thanks for the explanations and illustrations.
              I just read about all the gear types in Wiki.
              Seems indeed that i confused something here. I think i also made a translation error. Or Leo did
              One death is a tragedy; one million is a statistic.

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              • Originally posted by cbo View Post
                No, there is no herringbone gears in the Tiger final drive. It is all straight gears, but used in a planetary configuration (see below).

                I've never seen herringbone gears mentioned in relation to the Panther either. According to Speilberger, the proposed type was an "Umlaufgetriebe" - planetary gear - that worked fine.

                I'm wondering whether this confusion with the herringbone gears come from a translation error somewhere? They are two rather different things, after all (See below).

                Tiger I final drive:


                Sherman differential, brakes and final drive:
                'Gear group 100B2' is a perfect example of a herringbone type gear wheel as is its mating pinion.
                It isn't a type of gear such as planetary or Merrit Wilson, it is just a method for producing gear wheels to go into a final drive or differential, whatever type it is.

                Comment


                • One other thing to note is the relative size of the two gears. In the Sherman they are internal and the ratio is smaller than in the German tank final drive. That means the German design has far more stress on it, by design, than the US one. It is also far more subject to torque issues when the vehicle turns than the US one that inherently is designed to cancel much of that out.

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