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© Copyright Hewland Engineering Limited
11 April 2000
General Technical Bulletin No. 13
TPT Differential Bevel Gears
In line with Hewland Engineering’s constant quest to improve and develop its products, the TPT differential bevel gears have been
redesigned to improve the tooth strength and smoothness of operation.
In order to identify the new designs, all variations of the TPT gears cut to the revised specification will have a “D” suffix in the part
number. e.g.
TPT-213-6D
TPT-213-5AD
On the new components there will also be a tool tip groove to indicate the new form, on the side bevels this will be on the o.d. of the
core plate splines, on the planet bevels it will be on the front face, toe end of gear.
It is recommended that that the “D” specification bevels are always run with a mating gear of the same specification.
In extreme circumstances it may be possible to run “D” specification bevels with the older spec. bevels.
The user must realise this is
not condoned by Hewland Engineering.
Note:
If the new “D” spec. planet gears are run with the older spec TPT side bevel gears, they will have a reduced backlash/clearance
figure. This may result in incorrect operation of the differential, as the preload will be applied across the bevel gear teeth and not the
side ring gears/ramps, causing premature wear of the components.
If “D” specification side bevel gears are run with older spec. TPT planet gears there will be an increase in the backlash/clearance,
which may result in failure due to increased shock loads.
Colin Reynolds