Forces applied on the bolts in the bike's hinge

[kielbasa]

Very soft suspension and sensitive riding could possibly approach that but the Impulse time would often be a small fraction of the event when the rider and bike are taken by surprise or for an unusual angle of 'disturbance'.

kg is a measure of mass not force. You should try to tidy that up (SI helps here).

I took a shortcut. 1080MPa x 50,25mm2 = 54250 N --> (roughly equals to a mass of 5400kg)

 

[kielbasa]

I'm just wondering, if you look at my cross-section drawing, you'll see that the shear force is applied where two parts of the frame meet and where the bolt is thicker (cylindrical, not threaded part). Why does the bolt get cut off in the threaded part if the cylindrical part of the bolt is supposed to carry all the load and it sits tight in the hole?

 

[Lnewqban]

Why does the bolt get cut off in the threaded part if the cylindrical part of the bolt is supposed to carry all the load and it sits tight in the hole?

The flaw of this design is that there is always play between the bolt and the aluminum housing (otherwise the hinge would not be easily rotated).

If the bushing is plastic, it allows some additional relative movement due to temporary deformation under cyclic load.

With time, the hole in the aluminum housing (as well as the bushing) will expand, increasing the back-and-forth flexing of the cylindrical section of the bolt respect to the fixed threaded section.

All the above transfers shearing and bending loads to the weakest point of the bolt: the treaded neck.

Note how the Generation 2 shown in post 9 has two lateral set screws (1 and 2), which combined with the cylindrical pin, eliminates that problem.

It seems that the housing has enough meat to tap two or four holes for adding similar lateral set screws and improve the assembly of your bike by restricting any lateral movement of the bolts.

 

[Tom.G]

Perhaps a better design would be a bolt that goes all the way thru the hinge, with a locking nut or cotter pin to keep the nut on. Of course it needs to be threaded only away from the load-bearing area.

You may need a custom hinge made/machined for that approach though.

Is there a chance the bike manufacturer as upgraded the design yet?

 

[kielbasa]

Perhaps a better design would be a bolt that goes all the way thru the hinge, with a locking nut or cotter pin to keep the nut on. Of course it needs to be threaded only away from the load-bearing area.

You may need a custom hinge made/machined for that approach though.

Is there a chance the bike manufacturer as upgraded the design yet?

Take a look at one of my previous posts where I attached two drawings with two different hinge generations.
They did upgrade the hinge in the way You described, however, the drilled hole where the pin slides across the hinge (I assume) must be the same diameter at full length. Mine is not. (take a look at my cross-section drawing too.

 

[sophiecentaur]

I took a shortcut. 1080MPa x 50,25mm2 = 54250 N --> (roughly equals to a mass of 5400kg)

Your "shortcut" took you down a blind alley. A Force doesn't ever 'equal' a mass. What would your mass be doing to be equivalent to that Force? It would be gently resting on the ground. If you are not familiar with Newtons then perhaps you should have more contact with the unit and then you'd use it as a matter of course. Imperial Units have always suffered from the possible confusion between force and mass (you can tell me about slugs but how many members of the public knw about them?). Please don't bring that problem into SI situations.

 

[kielbasa]

So far, so good. I found a turner who made the same-looking bolts (he modified some strong truck's engine bolts, he mentioned they're grade 10.9 steel ) and I installed them on my bike. We will see what happens, hopefully, they won't break.