Note: Descriptions are shown in the official language in which they were submitted.
I
on
Counter shaft Transmission
Technical Field
This invention relates generally to a
counter shaft transmission for a vehicle or the like,
and more particularly to a counter shaft transmission
having a plurality of forward and reverse speeds using
lo constant mesh gearing and a plurality of fluid
actuated, rotating clutches of the interleaved multiple
plate and disc type.
Background Art
Counter shaft transmissions having a plurality
of speed ratios in each direction of operation are
particularly useful in the drive line of vehicles such
as earth moving wheel loaders, rubber tired log
skidders, track-type tractors, and other off-highway
heavy duty vehicles. Such transmissions are
advantageous in that a plurality of rotating clutches
and associated gears can be so positioned on the usual
parallel shafts as to allow considerable flexibility in
adapting them to different vehicle space requirements.
A considerable number of speed ratios can also be
obtained with but minor changes to the translation,
while permitting a substantial number of similar parts
to be used for manufacturing economy.
For example, the following United States
counter shaft transmission patents are of general
interest to the art: Patent No. 3,064,488 issued
November 20, 1962 to AWL. Lee et at; Patent No.
3,080,767 issued March 12, 1963 to SO Price, Jr.;
Patent No. 3,425,293 issued February 4, 1969 to
HIS. Krawczyk et at; Patent No. 3,465,609 issued
.
I 6
September 9, 1969 to JOE'. Fisher et at; Patent No.
3,710,637 issued January 16, 1973 to JO Fisher et at;
Patent No. 3,~58,455 issued January 7, 1975 to
AL is son et at; Patent No. 3,913,411 issued
October 21, 1975 to JO James on; and Patent No.
4,341,127 issued July 27, 1982 to E. Stout.
Ilhile such counter shaft transmissions have a
considerable number of desirable features they are
deficient in several other respects. One of the major
problems with them is that if they are connected to the
output member of the engine and/or optional torque
converter assembly of the vehicle they require
excessive space above the axis of the input shaft.
Specifically, in some vehicular applications it would
be necessary to raise the floor plates and elevate the
entire operator station in order to obtain sufficient
clearance above the input shaft's axis to accommodate
large diameter components such as a rotating clutch
thereat.
Another factor of significance is that some of
these available transmissions have an excessive axial
length and/or an excessive transverse width so that
they cannot fit into the limited space available in a
vehicle.
Furthermore, a family of counter shaft
transmissions is needed which can effectively match
various vehicular speed requirements with the
elevation Al drop requirements between the input and
output axes. In other words, the transmission should
preferably be conveniently convertible to provide one
or more additional speed ratios with but minor
modification. In addition to such flexibility of
construction, and the need to provide both a short drop
and large drop capability, the transmission should be
able to provide various PRO options at the desired
elevation Al level.
I
--3--
Still further, the construction of many of the
prior art counter shaft transmissions is excessively
complex and costly. Moreover, they have other less
noticeable deficiencies such as having excessive
bearing speeds and/or clutch plate engagement speeds
under certain operating conditions, and these
deficiencies reduce the overall service life of the
transmissiolls.
Accordingly, what is needed is a family of
economical and compact counter shaft transmissions that
can provide at least three forward speeds and three
reverse speeds, and that can maximize parts commonality
and minimize the number of gears, clutches, shafts and
bearings that are required. In addition to having a
long service life by virtue of designing the bearings
and rotating clutches such that they do not function at
undesirably high operating speeds, the family of
transmissions should be capable of convenient
modification so that the individual transmissions can
satisfy different drop height requirements as well as
different numbers of speeds and speed ratio
requirements and thus be adaptable to a wide variety of
vehicular applications. In connection with such
vehicular use, each of the transmissions should
preferably be axially compact and of narrow width while
having a minimum elevation Al clearance above the upper
input axis in alignment with the engine output.
Disclosure of the Invention
The present invention is directed to
overcoming one or more of the above problems.
In one aspect of the invention there is
provided a counter shaft transmission having an input
first gear, a first counter shaft having a second gear
secured thereto and a third gear rotatable thereon, a
I I
--4--
first clutch for connecting the third gear to the first
counter shaft, a second counter shaft having a fourth
gear secured thereto and a fifth gear rotatable
thereon, a second clutch for connecting the fifth gear
to the second counter shaft, and the first gear being in
inter meshing engagement with the third and fifth
gears. Advantageously, a sixth gear is rotatable on
the second countershaftt a third clutch is used for
connecting the sixth gear to the second counter shaft,
and a seventh gear is secured to the second
counter shaft. A third counter shaft having an eighth
gear connected thereto which is inter meshed with the
sixth gear is provided as are coupling means for
selectively connecting one of the fourth and seventh
gears to the third counter shaft for driving it.
In accordance with another aspect of the
invention, a counter shaft transmission includes an
input first gear disposed on an upper axis, a first
counter shaft having a second gear secured thereto, a
third gear connected to the first gear and being
rotatable thereon, and first clutch means for
connecting the third gear to the first counter shaft. A
second counter shaft is provided having a fourth gear
connected to the second gear secured thereto, a fifth
gear connected to the first gear and being rotatable
thereon, second clutch means for connecting the fifth
gear to the second counter shaft, a sixth gear rotatable
thereon, third clutch means for connecting the sixth
gear to the second counter shaft, and a seventh gear
secured thereto. An elevation ally lower third
counter shaft is also included which has an eighth gear
convected to the sixth gear secured thereto, a ninth
gear connected to the fourth gear rotatable thereon, a
tenth gear rotatable thereon and connected to the
seventh gear, fourth clutch means for connecting the
~31~
--5--
ninth gear to the third counter shaft, and filth clutch
means for connecting the tenth gear to the third
counter shaft.
More specifically, the counter shaft
transmission of the present invention as described
above provides at least three forward speeds and three
reverse speeds with the input shaft being elevation ally
directly above the third counter shaft, and with the
first and second counter shafts being disposed in
generally side-by-side relation elevation ally between
the input shaft and the third counter shaft. In one
modification thereof, another gear can be added to the
input shaft, and a further gear and splitter clutch
added to the first counter shaft to provide three more
forward speed ratios. In a further modification an
additional high speed clutch and two gears are
effective with the splitter clutch and gears to provide
eight forward and four reverse speeds. Moreover, the
third counter shaft can serve as the output shaft and
I provide a relatively short drop height or can be geared
to an elevation ally lower output shaft to provide a
greater drop height in order to match various vehicle
requirements.
Brief Description of the Ryan
Fig. 1 is a diagrammatic, developed, but
substantially side elevation Al sectionalized view of a
three-speed forward and three-speed reverse
counter shaft transmission constructed in accordance
with an embodiment of the present invention;
Fig. 2 is a diagrammatic, enlarged cross
sectional view of a portion of Fig. 1 showing details
of construction of the first rotating clutch by way of
example;
Sue
Fig. 3 is a diayra~nmatic, end elevation Al view
o-f the counter shaft transmission of Fig. l showing the
relationship of the various shaft axes and the
constantly meshing gearing associated therewith and the
cutting plane of developed Fig. l;
Fig. 4 is a speed char for the transmission
of Fig. l showing the clutches which are engaged in
each of the forward and reverse speeds;
Fig. 5 is a diagrammatic, single line drawing
lo of thy major elements of the counter shaft transmission
of Fig. l in solid lines, and illustrating two
alternate embodiments in broken lines including
additional components for respectively providing six
forward and three reverse speeds and eight forward and
four reverse speeds and
Fly. 6 is a fragmentary, sectional view
showing another alternate embodiment of the
counter shaft transmission of Fig. l involving a
foreshortened construction of the upper input shaft.
Best Mode for Carrying Out the Invention
Referring to Fig. l, there is shown a
counter shaft transmission lo having a housing or drop
box 12~ and an upper input shaft 14 and a lower output
shaft 16 rotatable supported in the housing along an
input axis 18 and an output axis 20 respectively. In
addition, first, second and third counter shafts Of
intermediate shafts 22, 24 and 26 are rotatable mounted
within the housing respectively along axes 28, 30 and
32 which are parallel to each other and to the input
and output axes, and are disposed elevation ally between
the input and output axes as may be noted by reference
to Fig. 3.
The housing 12 is advantageously constructed
of two major pieces; namely, a front case portion or
front cover 34 disposed at the left when viewing Fig. l
~q~3~
I
and a rear case portion or main body 36 located at the
right. In regard to the general orientation of the
counter shaft transmission 10 it is contemplated that
when it is placed in a vehicle, not shown, the axes of
all of the shafts will normally be oriented parallel to
the vehicle's longitudinal centerline or along a
straight travel direction. Preferably, the input axis
18 will be in coaxial alignment with the output axis of
the vehicle's engine, not shown.
A stepped cylindrical bore 38 and a plurality
of blind cylindrically shaped stepped pockets 40, 42
and 44 are integrally defined in a front wall 46 of the
front case portion 34 along the axes 18, 28, 30 and 32
respectively. The front case portion also defines a
peripheral wall 48 that extends rearwardly from the
front wall and terminates with a rearwardly facing
coupling surface 50 located in a plane 52 normal to the
axes of the shafts 14,22,24,~6 and I In a like
manner a cylindrical bore 54, a plurality of blind
cylindrically shaped pockets 56 and 58t and a stepped
cylindrical bore 60 are integrally defined in a rear
wall 62 of the rear case portion 36. An encircling
peripheral wall 64 extends forwardly from the rear wall
and is provided with a mounting flange 66 which defines
a forwardly facing coupling surface 68. A first
plurality of threaded fasteners 70 extend through the
mounting flange of the rear case portion and are
screwthreadably received in the front case portion, and
a second plurality of threaded fasteners 71 extend
through the front wall 46 of the front case portion 34
and are screwthreadably received in the rear case
portion in order to secure them positively together and
to define an internal chamber 72.
The bottom of the rear case portion 36
includes a front wall 74 having a conically inwardly
tapering integral tube portion 76 defining a stepped
--8--
cylindrical bore I symmetrically arranged along the
lower axes 20 of the output shaft 16. The rear case
portion also defines a cylindrical bore 80 and a rear
face 82 encircling the bore, which are adapted to
releasable receive a service brake assembly 84.
Specifically, the service brake assembly 84 includes a
flanged brake body 86 which palatably extends forwardly
into the bore 80, and a rear cover 88 defining a
stepped cylindrical bore 90. A plurality of threaded
lo fasteners 92 extend through the cover and the brake
body and are screwthreadably received in the rear case
portion to positively secure the parts in place and to
define with the rear case portion an oil sup region
identified generally by the reference numeral 94 in
the lower part of the internal chamber 72. A partition
96 extends upwardly from the bottom of the rear case
portion 36 and a sheet metal baffle 98 is releasable
secured thereto. This baffle has a flat annular body
100 with a cylindrical opening 102 there through and a
JO U-shaped rearwardly extending flange 104 which serve to
divide the sup region 94 into a front or main oil
reservoir 106 and a slightly elevated rear cavity 108
having an oil level below that of the main reservoir
therein during operation of the transmission as will be
later explained
In the embodiment illustrated in Fig. 1, the
counter shaft transmission 10 has an upper rear, flanged
extension tube 110 which is piloted in the bore 54 and
releasable secured to the rear wall 62 by a plurality
of threaded fasteners 112. A first bearing assembly
113 is disposed in the extension tube for rotatable
supporting the rear end of the input shaft 14, and a
second bearing assembly 114 is disposed in the stepped
bore 38 for rotatable supporting the front end of the
input shaft. An input gear or first gear 118 is
~3~5~
I
connected to rotate with the input shaft near the front
end thereof, while a power take off (PT0) flange 120 is
connected to it at the rear end This PT0 flange is
particularly useful for driving auxiliary equipment
such as a winch on the vehicle, not shown.
As is illustrated best in Fig. 2, the front
end of the first counter shaft 22 is supported in the
stepped pocket 40 of the front case portion 34 by a
straight roller or needle bearing assembly 1220 And,
as shown in Fig. 1, the rear end of the first
counter shaft is supported in the pocket 56 of the rear
case portion 36 by a straight roller or needle bearing
assembly 124. A second gear 126 is mounted on the
first counter shaft in abutment with an annular shoulder
127 formed on the counter shaft and is preferably
connected for conjoint rotation therewith by an annular
fillet weld 128 as is illustrated in Fig. 2. A third
gear 130 is freely rotatable mounted on the first
counter shaft through an intermediate hub assembly 132
and is continually inter meshed with and driven by the
input gear 118. The hub assembly 132 has a hub or an
annular body 134 defining first and second external
splints 136 and 137, a distal end 13~, and an enlarged
proximal end 139 having an internal bore 140 in which
is mounted a flanged bushing or sleeve bearing 141~
The third Lear 130 has an internal splint 142 which is
intermeshingly engaged with the external splint 136 on
the hub 134, and the third gear is axially entrapped
between a shoulder 144 on the hub at the inner end of
the splint and a releasable retaining ring 146.
A first hydraulically engaged and spring
disengaged rotating clutch 152 can be selectively
engaged to connect the third gear 130 to the first
counter shaft 22 for conjoint rotation through the
second gear 126 in order to achieve a forward mode of
-10- it
operation. Gore particularly, the first clutch 152 has
a first plurality of annular plates 154 and a second
plurality of interleaved annular plates or friction
discs 156 connected respectively to an internal splint
158 formed on a drum 160 and to the external splint 137
on the hub 134. The drum 160 is secured to the second
gear 126 by any suitable means and defines a
cylindrical bore 163 within it that is disposed over a
cylindrical pilot surface 164 formed on the second
gear. An annular reaction plate 166 having a
cylindrical bore 168 and an external splint 170
connected to the internal splint 158 of the drum 160
rotates with the first counter shaft 22 and is limited
in its axial movement by a releasable retaining ring
15 172.
The first clutch 152 further has an actuating
piston 174 having an external splint 176 connected to
the internal splint 158 on the drum 160 so that it
rotates with the first eountershaft 22. An axially
outwardly opening pocket 178 having an inner
cylindrical surface 180 is defined in the piston in
order to telescopically receive the distal end 138 of
the hub assembly 132. In this connection a cooling
fluid passage 186 is provided in the first counter shaft
22 which is in communication with the loft or outermost
end of the pocket 40. In this way cooling fluid can be
directed through the front case portion 34 into the
pocket, axially along the passage 186 and radially
outwardly into an annular cooling fluid chamber 188. A
plurality of radially oriented passages 190 are formed
in the distal end 138 of the hub assembly 132 for
controllable directing the cooling fluid radially
outwardly to the interleaved plates 154 and discs 156.
An actuating chamber 192 is defined between
35 the piston 174, the first countershaEt 22, the drum
160, and the second gear 126, and can be supplied with
pressurized fluid via a passage 193 in a conventional
manner. With such pressurization the piston it urged
to the left when viewing Fig. 2 so that it presses the
interleaved plates 154 and discs 156 axially together
and against the reaction plate 166. Thus the third
Jo gear 130 is caused to rotate with the first
counter shaft. A plurality of compression springs 194
acting against annular seat means 195 on the first
counter shaft serve to positively disengage the first
lo clutch 152 by moving the piston to the right when
viewing Fig. 2 when pressure is reduced in the
actuating chamber.
Any forces tending to urge either the first
counter shaft 22 or the hub assembly 132 forwardly or to
the left when viewing Fig. 2 will be transmitted to the
housing 12 substantially independently of the straight
roller bearing assemblies 122,124 through a front
thrust washer 197 located between the housing and hub
assembly. Any forces tending to move these same
elements to the right when viewing Fig. 1 will be
transmitted to the housing through a rear thrust washer
199 located between the housing and a shoulder 201
formed on the first counter shaft.
Turning now to the second counter shaft 24
shown in Fig. 1, it can be noted to have a fourth gear
196 secured thereto which is continually meshing with
the second gear 126 so that the second counter shaft
always rotates in a direction opposite to the first
counter shaft 22. Fifth and sixth gears 198 and 200 are
freely rotatable mounted on the second counter shaft,
and with the fifth gear 198 being continually
inter meshed with and driven by the input gear 118 as
can best be visualized by reference to Fig. 3. A
second clutch 202 is used to connect the fifth gear 198
US to the second counter shaft for a reverse drive, and a
~L~3~S16
-12-
third clutch 204 is used to connect the sixth gear 200
to the second counter shaft for a second speed
condition. Although illustrated only diagrammatically
in Fig. 1, the clutches 202 and 204 are of the multiple
plate and disc type and are similar in construction to
the first speed clutch 152 described immediately above
as can be appreciated by reference to the drawings. It
can be further seen that the second counter shaft 24 is
rotatable supported in the pockets 42 and 58 through
lo straight roller or needle bearing assemblies 206 and
208 respectively, and that a seventh gear 210 is
releasable connected for conjoint rotation therewith as
by a splint joint 212.
The third counter shaft 26 is advantageously
displaced axially rearwardly a preselected distance
with respect to the first and second counter shafts 22
and 24 for optimized compactness, and is rotatable
mounted in the front stepped pocket 44 via a straight
roller or needle bearing assembly 214. The rear
portion of the third counter shaft is supported in a
somewhat larger capacity straight roller bearing
assembly 216 in the stepped bore 60, and is releasable
connected to a splinted steering pump drive shaft 218.
A steering pump 220 is releasable secured to the rear
case portion 36 by any suitable means and is
continually driven by the third counter shaft via the
drive shaft.
An eighth gear 222 is preferably weldable
secured to the third counter shaft 26 in the same manner
as the gears 126 and 196 are secured to their
respective counter shafts 22 and 24. A ninth gear 228
is mounted for free rotation on the third counter shaft
26, and is selectively connected whereto by a fourth
clutch 230 which can provide a third speed condition.
A tenth gear 232 is also freely mounted on the third
-13-
counter shaft, and is connectable thereto by hydraulic
actuation of a fifth clutch 234 which can provide a
first speed condition. Because of the axially
rearwardly displaced, but nested relationship of the
third counter shaft 26 to the second counter shaft 24,
the gears 228, 222 and 232 are disposed in aligned and
continually inter Meshing engagement with the gears 196,
200 and 210 respectively. The fourth and fifth
clutches 230 and 234 are preferably like the first
lo clutch 152 described in detail earlier.
While it may be desirable to use the third
counter shaft 26 as the output shaft in those vehicles
having less elevation Al distance between the input and
output axes, the embodiment of Fig. 1 has an eleventh
gear 235 that is releasable secured to the third
counter shaft by a splint joint 236. This eleventh gear
serves to drive a relatively large diameter twelfth
gear 237 conjointly coupled to the output shaft 16 by a
shaft splint 238. A hub 240 forming part of the
service brake assembly 84 is connected to the same
shaft splint, so that when the service brake assembly
is actuated by release of pressure fluid from a chamber
242 an actuating piston 244 will be moved leftwardly
when viewing Fig. 1 by a Belleville compression spring
246. This will axially compress a plurality of
alternately interleaved plates and discs 248 together
in a well known manner, as is only diagrammatically
indicated, so that the hub 240 can be frictionally
connected to the rear case portion 36. this brakes the
output shaft 16 and the front and rear wheels, not
shown, which can be respectively driven through a front
connecting flange 250 and a rear connecting flange
252. Advantageously, the flange 250 is nestable
received within the tube portion 76 of the housing 12
and this permits a compact connection with the
associated axle of the vehicle, not shown.
-14- ~X3~
The output shaft 16 is rotatable supported by
a pair of opposed tapered bearing assemblies 254 and
256 in the stepped bores 78 and 90 respectively, and
when it rotates the twelfth gear 237 is disposed in
relatively close proximity to the flange 104 of the
baffle 9B. Accordingly, the teeth of the twelfth gear
urge cooling fluid upwardly and forwardly over the
edges of the U-shaped flange 104 of the baffle 98 into
the reservoir 106 in order to decrease the fluid level
lo in the cavity 108. In this regard it is to be noted
that the flange 104 relatively tightly encircles or
conforms with the lower periphery of the flanged brake
body 86 and provides minimal clearance there between so
that only a small amount of fluid from the reservoir
15 can enter the cavity 108 from the reservoir 106 because
of the reservoir's elevation ally greater fluid level.
This minimizes horsepower losses in cavity 108 that
would otherwise occur due to fluid churning and
aeration problems.
Industrial Applicability
In operation, the input shaft 14 of the
counter shaft transmission 10 shown in Figs. 1 and 5 can
- be driven by the engine of the vehicle Andre by the
output member of an optional torque converter mechanism
as is well known in the art, although not illustrated.
This will simultaneously drive the third gear 130 and
the fifth gear 198 because the input gear 118 on the
input shaft is inter meshed with both of them. Assuming
that a first forward speed is desired, the operator so
controls the vehicle as to cause the first clutch 152
and fifth clutch 234 to be hydraulically actuated so as
to engage the interleaved plates thereof together.
This respectively connects the third gear 130 for
conjoint rotation with the first counters hat 22, and
-15-
the tenth gear 232 for conjoint rotation with the third
counter shaft 26. Accordingly, the output shaft 16 is
driven at a relatively low speed ratio by way ox gear
pairs 118-130, 126-196, 210-232 and 235-237. Note is
made that counter shafts 22 and 24 always rotate in
opposite directions because the gears 126 and 196
rotate respectively therewith and yet are continually
inter meshed. Also, since the fifth clutch 234 is
subject to greater torque loading due to its higher
lo speed reduction ratio it is preferably larger in
diameter than the other rotating clutches 152, 202, 204
an 230, which can advantageously be of the same lesser
diameter for parts commonality.
As indicated by the speed chart of Fig. 4, it
is only necessary to disengage the fifth clutch 234 and
to engage the third clutch 204 in order to shift the
transmission 10 from first to second forward speed. In
this mode, the speed reduction ratio is reduced and the
output shaft is driven at a higher speed by way of gear
20 pairs 118-130, 126-196, 200-222, and 235-237.
In order to shift from second to third speed
forward, the third clutch 204 is disengaged and the
fourth clutch 230 is engaged. Hence, only one clutch
need be engaged from first to second, or from second to
third which is advantageous from both the torque
loading and control standpoints. In third gear
forward the drive is by way of gear pairs 118-130,
126-196, the gear 228 driven by the year 196 and to the
third counter shaft 26, and by the gear pair 235-237.
In first reverse, as shown by the chart of
Fig 4, the low speed clutch 234 is engaged as it is in
first forward. However, in the reverse mode of
operation the second clutch 202 is always engaged
Torque is thereby transmitted to the output shaft 16
35 via gear pairs 118-198, 210-232, and 235-237.
Lo
-16-
To achieve second reverse, the low speed
clutch 234 is disengaged and the third clutch 204 is
engaged. Output shaft 16 is driven by gear pairs
118-198, 200-222, and 235-237.
Lastly, to shift to third speed reverse, the
third clutch 204 is disengaged while the fourth clutch
230 is engaged. Again, as in forward, it is only
necessary to engage a single clutch to change reverse
speeds. Torque is transmitted in third speed reverse
lo through gear pairs 118-198 and 196-228 to the third
counters hat 26, and from there to gear pairs 235-237.
Referring now to Fig. 5, and to a first
alternate embodiment of the counter shaft transmission
10 which includes some additional components as is
diagrammatically shown by the broken lines at the upper
right portion thereof. Specifically, a thirteenth gear
2~8 can be secured to the input shaft 14 rearwardly of
the first gear 118, a fourteenth gear 260 can be
rotatable mounted on the first counter shaft 22, and a
sixth or splitter clutch 262 can be used to selectively
connect the fourteenth gear 260 for conjoint rotation
with the first counter shaft. This will enable the
second gear 126 to be driven at either one of two
speeds as determined by the ratio of gear pair 118-130
25 or gear pair 258-260. With such construction the
counter shaft transmission 10 can provide from four to
six forward speeds in addition to the three reverse
speeds discussed heretofore.
A second alternate embodiment of the
counter shaft transmission 10 includes some additional
members over those described with respect to the first
alternate embodiment. Such new members are illustrated
in broken lines at the lower left portion of Fig. 5 and
include a fifteenth gear 264 freely rotatable mounted
on the output shaft 16 and continually inter meshed with
3~ilrj~
-17-
the ninth gear 228 on the third countershaFt 26.
seventh clutch or high speed clutch 266 can then be
used to selectively connect the fiEteeilth gear 264 for
conjoint rotation with the output shaft. This is
effective to provide up to eight forward speeds and
four reverse speeds. For example, the first clutch 152
can be used progressively with the fifth clutch 234,
the third clutch 204, the fourth clutch 230, and the
seventh clutch 266 to provide the first to the fourth
lo forward speed ratios. Then the sixth clutch 262 can be
used progressively with the same clutches 234, 204, 230
and 266 to provide the fifth through eighth forward
speed ratios. In reverse the highest speed would be
provided by the engagement of the reverse clutch 202
with the seventh clutch 266.
Another alternate embodiment is shown by the
auxiliary view ox Fig. 6, wherein the input shaft 14'
is foreshortened in comparison with the input shaft 14
where no power take-off is required along the upper
20 axis 18. In this instance an end cap 268 is palatably
disposed in the bore 54 and releasable secured to the
rear case portion 36 by the fasteners 112. A stepped
pocket 270 is defined in the end cap and a tapered
roller bearing assembly 272 is seated in the pocket and
against a shoulder 274 formed on the input shaft I
for rotatable supporting the rear end of the input
shaft 14' in paired thrust absorbing relation to the
facing tapered roller bearing assembly 114 shown in
Fig. 1. With such alternative construction, all of the
30 shafts 14', 22 and 24 would be relatively short and
define a particularly axially compact construction at
the upper portion of the transmission 10.
As can be visualized with reference to Fig. 3,
an upright or vertical plane 276 preferably passes
through the input axis 18, the axis 32 of the third
-18-
counter shaft 26, and the axis 20 of the output shaft
16. The axes I and 30 of the first and second
counter shafts 22 and 24 respectively are substantially
symmetrically arranged on the opposite sides of the
vertical plane and elevation ally between the upper axis
18 and the intermediate axis 32 of the third
counter shaft 26. The third counter shaft could clearly
serve as the transmission output, if desired, by merely
removing the steering pump 220 from the location
10 illustrated in Fig. 1. Moreover, the axes 28 and 30
are so located relative to a horizontal plane 278
passing through the input axis 18 that the relatively
large diameter gears 126 and 196 do not extend to any
substantial degree above such horizontal plane. Since
the input gear 118 is desirably relatively small in
diameter, the instant transmission requires only a
minimal vertical clearance height pa above the input
axis 18 as is indicated in Fig. 3. This is a
significant feature in many vehicle applications. Note
20 that the overall width OW" of the gears 126 and 196 as
indicated in the drawing is also minimal. Still
further, the overall drop can be tailored from the
minimum distance illustrated between axes 18 and 32 to
a maximum distance corresponding to the distance
between axes 18 and 20. end, the overall speed
reduction ratios can also be conveniently changed by
modifying only the output gears 235 and 237 and/or by
modifying the input gears 118, 130 and 198.
In view of the foregoing, it is apparent that
I the counter shaft transmission 10 is simple and rugged
in its construction, and is of light weight. Moreover,
it is adaptable to a large number of vehicular
applications since the output shaft drop height from
the input centerline can be conveniently varied and the
number of speed ratios varied as explained heretofore.
I
--19--
The first and second clutches 152 and 202 are laterally
in longitudinal alignment, and the third and fourth
clutches 204 and 230 are elevation ally in longitudinal
alignment in order to conserve space. Furthermore, the
S longitudinally offset and elevation ally nested nature
of the second and third clutches 202 and 204 on the
second counter shaft 24 and the fourth and fifth
clutches 230 and 234 on the third counter shaft 26 is
particularly advantageous from an overall compactness
lo standpoint. Also, the construction of the region of
the input shaft 14 minimizes transmission height and
provides a highly desirable PRO location.
Another feature of the counter shaft
transmission 10 is that the physical location of the
first or low speed providing clutch 234 is such as to
minimize high speed rotation of other elements of the
transmission under normal operating conditions. In
certain prior art transmissions it is understood that
bearing speeds considerably above about 5,000 rum, for
example 8~0~0 rum, are experienced by the inactive
gears. Whereas in the counter shaft transmission 10 the
bearing speeds of the inactive gears during roaring of
the vehicle are generally limited to a maximum of about
5,000 rum with an assumed speed of 2400 rum for the
I input shaft 140 Thus the bearings will live
substantially longer and/or can be of somewhat less
sophisticated and more economical design.
Other aspects, objects and advantages of this
invention can be obtained from a study of the drawings,
the disclosure and the appended claims.
