39 replies to this topic

[Dusky]

Hi guys!

So, the transfer gears on a mini have always been a bit of a problem with the weak idler bearing. But straight cut drops are not that amazing in a road car if you don't want to damage your hearing.

Has Anyone ever tried herringbone gears? Was there an obvious disadvantage im overlooking?As far as I know it is basicly a double V shaped helical so no noice and almost no sideload.i could get these made in batches too if someone would be intrested. But would test them first, any thoughts?

[Stevie W]

Hi Dusky,

 

A quick Google search shows the only real disadvantage of these types of gear is the manufacturing cost as special cutting equipment is needed to manufacture them.

Advantages are no axial load as the two teeth angles cancel any load out and thrust washers either side of the gears are not needed.

Apparently they're also very quite and capable of transmitting hi torque levels at high speeds!!

 

Cheers, Steve.

[Spider]

As Steve said, cost is really the only issue. Keep in mind too, that it's 3 gears you need, not just one!

[Dusky]

Happy to hear this :)

I got a very friendly friend ( hehehe) who has the facilities to make those gears.

Out of intrest : do you think people would be intrested in this? ( if the price can be made right ofcourse)?

 

Might be a nice addition to the current line of gears we have!

think my winter will involve a lot of testing and drawing, but thats where winters are for! :)

[Alex_B]

I have been thinking about doing this myself, the only disadvantage that I can see is cost as mentioned above. The design of a gear involves a lot anyway and then you have to work out a way to machine them, it is possible however it will be costly. But I plan to look into it after I have finished the engine build design and planning. 

[Spider]

Happy to hear this :)

I got a very friendly friend ( hehehe) who has the facilities to make those gears.

Out of intrest : do you think people would be intrested in this? ( if the price can be made right ofcourse)?

 

Might be a nice addition to the current line of gears we have!

think my winter will involve a lot of testing and drawing, but thats where winters are for! :)

 

YES.

 

EN36B is THE steel to make them from.

[stoneface]

I'm interested, but when you say expensive what sort of figures are you talking?

Expensive is relative, less than £500, more than a £1000 ?

[Dusky]

I'm interested, but when you say expensive what sort of figures are you talking?
Expensive is relative, less than £500, more than a £1000 ?

A very very big guesstimate would be around (but under) 500 quid, given material cost and machining, but this would also mean I ll have to sell/ make batches. The bigger the batch the cheaper

[stoneface]

Thanks Dusky, I'm interested.

Although I don't have the power the turbo minis have (only 112lbft) and some of them run helical drops, I've never wanted to risk winding the idler gear into the casing as I can't just get another.

And, I hate the noise of my straight cut drops.

[Carlos W]

It's really interesting to see people carrying on making improvements to minis.

 

I'm following this, whether or not I'd buy will come down to price

[gadget555]

Me too it would be down to price and availability good idea though  

[ChopperHarris]

Just a point of interest..Citroens badge is based on such gears as they were pioneered by him

[Dusky]

Thats where I got my inspiration :)

[dklawson]

I will be interested to hear how this proceeds.  As Spider said, remember it will be 3 gears, not 2.  

 

My only technical concern relates to the load bearing area.  Most herringbone gears I have seen include a relief cut between the "chevrons" so the gears are easier to machine.  That gap will reduce the load bearing capacity of the gears.  While I have seen some gears made without the relief cut I'm sure that will add significantly to the cost.

[nicklouse]

I will be interested to hear how this proceeds.  As Spider said, remember it will be 3 gears, not 2.  

 

My only technical concern relates to the load bearing area.  Most herringbone gears I have seen include a relief cut between the "chevrons" so the gears are easier to machine.  That gap will reduce the load bearing capacity of the gears.  While I have seen some gears made without the relief cut I'm sure that will add significantly to the cost.

that was "solved" years ago and has also been transered to some CNC machine tools.

 

a full compliment gear set should be possible and i would say would be expected.