Helix angles on compression driven clutches

[Metallicat]

Why do helix angles matter or make a difference on compression spring secondary clutches?

Sorry, this has puzzled me for years.

 

[iceback]

Something has to keep the shift linear.

 

[Metallicat]

If is compression only on the spring, then why does it even matter how the two shieves rotate in relation to each other? That is what a helix does. It rotates the movable shieve and increases spring rate and side pressure in order to control belt pressure and upshift, on a standard system. On a compression only system, why would the helix angle matter at all? There is no twisting of the spring. Just compression. Or does the helix angle somehow slow down or moderate the transfer of power?

 

[KnappAttack]

Helix works the same on a compression spring as it does a torsion spring, it provides resistance on the upshift and the spring still has an effect on the "torsional effect" as well, unless you have a bearing or plastic "swivel abutment" under the spring like Ski-Doo has or the aftermarket provides. The spring has more effect on backshift on a compression setup than the helix does.

Why are you asking anyway? There are no compression setups for a Yamaha secondary anyway.

 

[Metallicat]

Helix works the same on a compression spring as it does a torsion spring, it provides resistance on the upshift and the spring still has an effect on the "torsional effect" as well, unless you have a bearing or plastic "swivel abutment" under the spring like Ski-Doo has or the aftermarket provides. The spring has more effect on backshift on a compression setup than the helix does.

Why are you asking anyway? There are no compression setups for a Yamaha secondary anyway.

 

[Metallicat]

None of the patrons on the other sites provided a satisfactory response so I thought I would ask here. Thank you for your further explanation.

 

[ClutchMaster]

Why do helix angles matter or make a difference on compression spring secondary clutches?

Sorry, this has puzzled me for years.

Helix angle in a compression spring secondary still does the same thing as in a torsion spring secondary.
Look at your secondary, when rotational force is applied to the secondary moveable sheave, it forces the buttons or rollers to slide on the helix angle. This takes the rotational force and changes it into belt clamping force. With a lower angle helix there’s more physical clamping force generated from the helix ramp. A higher angle ramp will have less belt squeezing force, but will shift out faster.

The secondary spring is used for maintaining belt contact with the sheaves. Most of the secondary clamping is done through the forces generated by the helix and sheaves that I just described.

Secondary Springs can be used to fine tune the shift out.
Springs tend to have more effect on the shifting at full shift out, where the helix isn’t generating as much side force and the spring is fully compressed

 

[Metallicat]

Helix angle in a compression spring secondary still does the same thing as in a torsion spring secondary.
Look at your secondary, when rotational force is applied to the secondary moveable sheave, it forces the buttons or rollers to slide on the helix angle. This takes the rotational force and changes it into belt clamping force. With a lower angle helix there’s more physical clamping force generated from the helix ramp. A higher angle ramp will have less belt squeezing force, but will shift out faster.

The secondary spring is used for maintaining belt contact with the sheaves. Most of the secondary clamping is done through the forces generated by the helix and sheaves that I just described.

Secondary Springs can be used to fine tune the shift out.
Springs tend to have more effect on the shifting at full shift out, where the helix isn’t generating as much side force.

Thank you, I get it now

 

[VX1R]

Helix angle in a compression spring secondary still does the same thing as in a torsion spring secondary.
Look at your secondary, when rotational force is applied to the secondary moveable sheave, it forces the buttons or rollers to slide on the helix angle. This takes the rotational force and changes it into belt clamping force. With a lower angle helix there’s more physical clamping force generated from the helix ramp. A higher angle ramp will have less belt squeezing force, but will shift out faster.

The secondary spring is used for maintaining belt contact with the sheaves. Most of the secondary clamping is done through the forces generated by the helix and sheaves that I just described.

Secondary Springs can be used to fine tune the shift out.
Springs tend to have more effect on the shifting at full shift out, where the helix isn’t generating as much side force and the spring is fully compressed

Great explanation ClutchMaster. I hope that you mend up soon and are riding this winter!