Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to a shift clutch,
preferably a double shift clutch, disposed between two
gear wheels, shafts or clutch bodies to be coupled.
In the case of multi-shaft transmission gearing,
which comprises a two-stage group or split gears for
example disposed upstream or downstream in order to
increase the number of gears and whose centrally arranged
drive or output shafts are not maunted in a fixed manner
for the purposes of load compensation and which are
shifted by means of a synchronizer mechanism, preferably
a disc synchronizer, considerable di-fficulties are
encountered in centering these shafts during shifting, as
the shaft is released from the central gear wheel.
The object of the invention is therefore to
overcome this difficulty by simple means without impair-
ing the quality of the load compensation.
This object is achieved from a broad aspect by
providing a shift clutch having a synchronization device
and disposed on a central shaft of a multi-shaft trans-
mission gearing. A synchronizer body is arranged to be
rotationally and axially fixed and supports a-sliding
sleeve via teeth and friction mechanisms and gearing
preferably disposed on both sides. Half of the friction
mechanism and the shift gearing is disposed on a clutch
body. A gear wheel or a further shaft is also provided.
; The clutch is characterized in that a shiftable centering
mechanism is disposed between a central gear wheel and
the shaft supporting the synchronizer body.
If a centering mechanism is dlsposed in the
area of the shift cl.utch, it is possible to actuate the
latter independently of shifting so that it is only
operative if neither the friction mechanism nor the
shift gearing are guiding the shaft.
Simple solutions are achieved by utilizing
three simple pins in the synchronizer body which pins
merely project from smooth radially extending bores.
Bearing may take place for example on a clutch body
on the central gear wheel or a clutch body connected
to the central gear wheel or on the annular surface
projecting on the disc suppor-t~
The control may also be simply resolved using
for example the wedge-shaped or convex configuration
of at least three tooth tips of the inner gearing of
the sliding sleeve, in which the wedge arrangement or
the convex configuration must be shaped such that in
the area of the central position of the sliding sleeve
the shaft is centered via the synchronizer body and the
centering mechanism in the radial direction by the central
gear wheel, whilst the latter is itself guided by the
gear wheels, which are disposed on the transmission shaft.
A slide ring di.sposed between the pins.and
the centering surface which is rotationally secured with
respect to the pins, may prevent premature wear of the
pins.
If this slide ring has very thin walls and is
constructed with an internal diameter which is greater
than the di.ameter of the centering surface, sliding
friction only takes place during centering and only in
the area of the pins.
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A preferred embodiment of the present
invention will now be described with reference to an
example thereof illustrated in the accompanying drawing
in which:
The single Figure shows a cross-section
through a shift clutch.
In this Figure the drive shaft 2 selectively
drives two central gear wheels 1, 6, which are freely
disposed about the shaft and are of a first or second
drive constant. The gear wheels are guided in the radial
direction by gear wheels (not shown) on the transmission
shaft.
A synchronizer body 3 is connected in an
axially and rotatably fixed manner with the shaft 2,
wh:ich body 3 supports an internally geared sliding sleeve
5 via external gearing.
The drive shaft 2 is uncoupled, at least in
~; the area of the two drive constants, in the radial
direction, and is guided for the purposes of load
; 20 compensation via a disc, for example, clutches or shift
; gearing by one of the gear wheels of the first or
second constant.
The outer disc support 71, whic`n also supports
the locking teeth, is in locking connection with the
synchronous body 3. The central gear wheels 1, 6 are
connected with the clutch body 12, 62 which also support
the shift gearing 13. ln addition the central gear
wheels also support the inner discs 73 of the friction
mechanism 7. The thrust plungers 8 coo~erate with the
sliding sleeve 5 and the pins 41 of the centering mechanism
-- 4 --
5S~3~
and are disposed about the periphery of the
synchronizer body 3. These pins 41 project from
radially extending through bores disposed about the
synchroni.zer body. An annular centering surface 11 is
provided on the central gear wheel 1 which surface, in
the same way as the cam 51 on the sliding sleeve 5,
cooperates with the pins 41. The centering surface is
in this respect, seen in the axial direction, disposed
in the plane of the pins and radially inwardly from
these. In order to counter the wear of these pins, a
slide ring 9 may be disposed between these pins and the
centering surface 11, which ring slides on the centering
surface and is rotationally secured with respect to the
pins 41~
It is preferable that the slide ring 9 be
provided wi.th very thin walls and has an inner diameter
which is larger than the centering surface, so that it
only lies on the centering surface in the area of the
pins during centering - i.e., when the pins are pressed
radially inwardly and are supported. The cam 51 may
in this respect comprise at least three wedge-shaped
surfaces, facing the pins and disposed i.n the tips of
the teeth of the inner gearing 53. The maximurn height
of the tips lies at the center of the axial prolongation
of the sliding sleeve 5~
Xf the sliding sleeve is moved to the left,
as shown at; position X, where the drive shaft 2 is
maintained approximately centrally via the central gear
wheel 6 and the shift gearing 72 taking into account
the load compensation, this guide provision
35S~5
is lost as a result of the release of the shift gearin~
and the centering is undertaken by the centering mecha-
nism. The cam 51 on the sliding sleeve 5 presses the
pins 41 radially inwarclly until there is direct
support or support via the slide ring 9 on the
annular centering surface 11 on the central gear wheel 1.
If the sliding sleeve is displaced further to the left
across the center, this centering is again released and
the guiding of the shaft 2 is then, for example in the
case of cone friction mechanisms, undertaken by the
left-hand friction mechanism 7 and in accordance with
the synchronization of the shift gearing 13 on the
central gear wheel 1.
By means of a suitable configuration of the
cam 51, a~relatively wide area in the central position
with a quasi-constant ma~imum height or a convex forma-
tion with a relatively large radius, the time for
centering via the centering mechanism, in the case in
which the sliding sleeve 5 is moved over, may be embodied
such that guiding of the drive shaft 2 takes place either
via the shift gearing taking into account the-load
compensation or via the friction mechanism or even via
the centering mechanism.
The arrangement of a centering mechanism is
not limited to this embodiment, as it is also possible
for an output shaft, which is pivotably mounted for the
purposes of load compensation, to be centered in the
same way. It is also conceivable for the entire construc~
tion of the shift clutch to be embodied differently, and
there~ore in order to achieve synchronous running a cone
55~:3S
friction mechanism could for example be used or the
annular centering surface could be arranged on a clutch
body rather than directly on a central gear wheel.
It is within the ambit of the present invention
to provide any obvious modifications of the example of
the preferred embodiment illustrated herein, provided
such modifications fall within the scope of the appended
claims.
