The variably timed transmission comprises three superposed concentric
members :
the first member is the drive shaft [17] located
in the inner section,
the second member is the sleeve [28] of gear
[20] located in the outer section and
the third member is the sliding tube [32]
located in the intermediate section between the two aforesaid members.
Said sleeve [28] is held in a bearing plate
[15] by means of a suitable double-row angular contact bearing [16]
mounted between the bearing plate [15] and sleeve [28].
Said bearing plate [15] is secured to the engine
unit [1] so that the variably timed transmission forms a separate
assembly with respect to the shaft [18] of the short-stroke crankshaft
[5].
For this purpose , the variably timed transmission
and the short-stroke crankshaft [5] are designed each with their
own shaft [17] and [18].
The abuting ends of shaft [17] of the variably
timed transmission and of shaft [18] of the short-stroke crankshaft
[5] are provided with straight male splines and corresponding female
splines, so as to permit their coupling within the engine unit [1]
through an axial slide movement when the bearing plate [15] in engaged
in an opening of the engine unit [1].
The bearing place [15] is centred with respect
to shaft [18] of the short-stroke crankshaft [5], so as to permit
sel-centering of shaft [17] with respect to shaft [18] , the latter
also acting as a free bearing for shaft [17] when the bearing plate
[15] is applied against the engine unit [1] ; such means permits
the variably timed transmission to be removed from the engine unit
[1] without having to remove the short-stroke crankshaft [5].
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