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MAKE: SynchroLite ~ Power Train - Secondary Reduction (planetary drive)

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See: OTHER: Mechanical - Gear - Planetary

SynchroLite

It looks like the 2 housing end caps 0309 and 0307 do not take any torque; they just support the internal ring gear. If this is the case then I would think that the walls etc. could be thinner and the bearings, in both, could be reduced in capacity. 

See also: DESIGN: Power Train - Reduction - Secondary - Teeth Layout 0134

See previous page for current tooth counts, ratio and speeds.

Frequency (approximate) of Tooth contact (re: Durability)

The following in this heading is now only approximate

RPM of sun = 2143

RPM of planetary ring = 571

RPM of planetary gear = 1224.6

Assuming 3 planetary gears.

Sun

2143 - 571 = 1572RPM x 3 planetary gears = 4716 contacts per minute.

Planetary

1224.6 x 2 contacts (sun and ring) = 2449 contacts per minute.

Ring

572 x 3 planetary gears = 1716 contacts per minute.

572 x 4 planetary gears = 2288 contacts per minute.

Re: Strength of teeth in Ring Gear

If steel ring gear is used then it should be narrower than planetary gears.

If aluminum ring gear is used then it should be wider than planetary gears.

1.77# if 7/8" wide in steel. If made in aluminum it must be wider but the aluminum portion that replaces the steel will weigh 0.63#. A total saving of 2.28# per helicopter.

 Maintence Idea

If aluminum ring gear is used then a magnetic chip detector will not pick up the aluminum. There for the oil should be removed, filtered (and the filter inspected) and replaced every say 10 hours.

 

Gear Rim Thickness

From article download from Internet:- The rim thickness below the root diameter should be a minimum of 1.5 times the whole depth of the root.

From viewing Bell 206 ring gear at BCIT:- The rim thickness is equal to the tooth depth, but the rim does extend out both sides beyond the teeth.

Ring Gear -

Pressure Angle:

14-1/2 degree pressure angle has higher contact ratio for a smoother quieter operation.

20 degree pressure angle has higher load carrying capacity.

Arrow Gear uses 20 degree for their standard spiral bevel gears.

Housing:

See: Cast Housings

Attachment of Overrunning Clutch:

  1. Use Race (0647) with keyways cut into mast ~or~
  2. Use Adapter Sleeve (0779), Nut (0776) and Locking Washer for friction lock on mast. PREFERED

 

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Last Revised: October 12, 2001