Note: Descriptions are shown in the official language in which they were submitted.
Description
Vehicle Transfer Gear and
Drive Line Brake Mechanism
Technical Field
This invention relates generally to a vehicle
transfer gear and drive line brake mechanism, and more
particularly to a depending gear transfer train and a
drive line brake assembl~ and a common lubrication
system therefor.
Background Art
~ome articulated vehicles, such as four-wheel
drive farm tractors, have a depending gear transfer
train for propelling the vehicleO The input of the
transfer train is connected to a multi-speed
transmission having a longitudinally oriented axis
located at a considerable elevation above the axes of
~o the wheels. A housing or drop box contains the
depending gear transfer train and provides a sump for
the transmission fluid. A pump is driven by the engine
of the vehicle which serves to direct fluid from the
sump through a control system for operating the
transmission and lubricating the components of the
transmission and the various gears and bearings of the
transfer train.
~ eretofore, a dry brake assembly has been
located externally of the drop box in the drive line to
the wheels for the purpose of serving as a parking
brake or auxiliary brake~ In such instance the primary
dynamic service braking function has been provided by
conventional brake mechanisms located at the individual
wheels of at least one axle. But improper use of the
relatively low energy capacity drive line brake
. ~ ~
362~6~
assembly by an unskilled operator has occasiona]ly led
to excessive heat build up and wear thereof so that
premature servicing problems are encountered.
Moreover, these dry drive line brake assemblies are not
usually positively sealed against the ingress of dirt
and foreign ma~ter with the result that wear of the
Eriction elements is accelerated.
In view of the aforementioned factors it is
desirable to make the known dry and open drive line
brake assembly a fully enclosed and wet drive line
brake assemhly in order to extend its service life and
to optionally increase its energy absorbing capacity.
Under optimum conditions that brake assem~ly could even
function as a dynamic service brake and result in a
savings because the individual wheel brake assemblies
could be decreased in capacity or eliminated entirely
with a reduction in overall cost.
If the wet drive line brake and depending gear
transfer train are enclosed in a common elevationally
lower compartment the rotating elements of the brake
assembly could churn through the lubricating fluid and
cause a horsepower loss. While it is well Icnown that
it is undesirable to rotate a gear or the like in an
appreciable amount of fluid it is not always simple to
avoid this problem. Not only are fluid dra~ losses and
fluid heating caused by this action, but also fluid
aeration which could detrimentally influence the
operation of the pump and associated control system.
U.S. Patent No. 1,220,810 issued to K. Alquist
on March 27, 1917 discloses a gear mechanism that is
directed to minimizing fluid drag losses by providing
an elevated reservoir in the casing to which the
lubricating fluid is directed by the tips of the gear
teeth pumping against an associated casing wall. In
other words, the ~ear teeth tips extend into a lower
fluid reservoir to a limited extent, and a relatively
low-fluid level is maintained therein by the action o~
the teeth tips as they sweep upwardly adjacent the
casing wall.
Although the above-mentioned patent describes
a mechanism that can be very effective in reducing
fluid drag losses during operation, it requires a
complex case and is not conveniently adaptable to the
drop box, transfer train and drive line brake assembly
discussed above.
Thus it would be advantageous to provide a
common housing for containing both the depending gear
transfer train and the drive line brake assembly so
that they can share the economics of a common
lubrication system in the vehicle.
Furthermore, the wet drive line brake assembly
should be capable of being conveniently remove~ from
the housing for servicing purposes. And, preferably,
these elements should be integrated in such a way that
fluid drag losses during operation of the vehicle are
minimized.
It is f~rther desirable to have a conveniently
releasable sump casing in order to better service the
oil intake components and to allow the total fluid
capacity to be varied for more effective matching to
vehicles of various sizes and horsepower ranges.
The present invention is directed to
overcoming one or more of the problems as set forth
above.
Disclosure of the Invention
In one aspect of the invention a vehicle
transfer gear and drive line brake mechanism includes a
depending gear transfer train having an output gear
connected to an output shaft on a lower axis and a
drive line brake assembly which is selectively
connectable to the output shaft on the lower axis.
Advantageously, housing means are provided for defining
an enclosed compartment containing the gear transfer
train and drive line brake assembly and a common
lubricating fluid therein. The housing means includes
a main case defining an opening on the lower axis, and
the drive line brake assembly includes a brake body
releasably secured to the case at the opening and a
plurality o annular plates and discs. ~dvantageously,
the drive line brake assembly is modularized so that it
is removable with the brake body from the output shaft
independent of the output gear.
More particularly, the housing means supports
the depending gear transfer train and drive line brake
assembly and with the brake body defines an enclosed
compartment therefor. The housing means further
features a baffle element that defines a sump chamber
and a brake chamber within the enclosed compartment and
is so constructed that rotation oE the output gear or
other member connected to the output shaft will cause
fluid to be directed away from the drive line brake
assembly outwardly of the brake chamber into the sump
chamber. This will reduce fluid drag losses.
Brief Description of the Drawings
Fig. 1 is a diagrammatic, side elevational
view of an articulated wheel-type vehicle showing the
arrangement of a portion of the power train thereof,
including an embodiment of the transfer gear and drive
line brake mechanism of the present invention, in
brGken lines;
Fig. 2 is a diagrammatic, elevational
S perspective view of the baffle element illustrated in
Fig. 5 to better illustrate details of construction
thereof;
Fig. 3 is an enlarged and diagrammatic
sectionalized view of the fluid egress opening in the
baffle element illustrated in Figs. 2 and 5, as taken
generally along line III III of Fig. 2, and with the
output gear added for clarity of operation;
Fig. 4 is an enlarged, sectional view of a
portion of the baffle element illustrated in Fig~ 5
showing the sealed edge thereof in conjunction with the
associated housing means; and
Fig. 5 is a diagrammatic and centrally
sectionalized side elevational view of the transfer
gear and drive line brake mechanism illustrated in
broken line form in Fig. 1, and showing details of
construction of the present invention.
Best Mode for Carryin~ Out the Invention
Referring initially to Fig. 19 a four wheel
drive vehicle 10 particularly adaptable to agricultural
use is illustrated. An engine 12 and a generally
cylindrical multi-speed transmission 14 coupled thereto
are mounted on the front section of the vehicle, and
the transmission extends generally longitudinally and
rearwardly into a transfer gear and drive line brake
mechanism lS constructed in accordance with the present
invention. In generall such mechanism can powerably
rotate front wheels 18 and rear wheels 20 of the
vehicle and can stop the vehicle.
As best shown in Fig. 5, the transfer gear and
drive line brake mechanism 16 includes a depending gear
transfer train 22 driven by the transmission 14. The
depending gear transfer train has an input gear 24
disposed on an upper longitudinally extending axis 26,
an output gear 28 disposed on a lower longitudinally
extending axis 30, and gear means 32 connecting and
transferring power between the input and output gears.
In the instant embodiment the gear means 32 includes a
single transfer gear or idler gear 34~ The output gear
28 is releasably connected to a stepped output shaft 36
by a spline connection 38, so that with rotation
thereof the front and rear wheels of the vehicle are
rotated. A drive line brake assembly 40 is operatively
associated with the shaft to stop rotation thereof
relative to housing means 42.
The transfer gear and drive line brake
mechanis~l 16 also includes a second input gear 44
rotatably supported within the housing means 42 on the
upper axis 26 and coupled to rotate with auxiliary
drive means 46. In the instant example the auxiliary
drive means includes an engine driven shaft 48 that
passes generally straight through the transmission 14
and powers certain hydraulic devices or pumps 50 as a
function of engine speed~ ~ power talce off (PT0)
clutch assembly 52 is generally contained and supported
within the housing means at the rear face thereof along
a third axis 54 located elevationally between the upper
and lower axes 26,30. The PT0 clutch assembly is
powered by another gear 56 which is in continuous
intermeshing engagement with the second input gear 440
More particularly, the housing means 42 of the
transfer gear and drive line brake mechanism 16 shown
in Fig. 5 can be seen to include a main case 5~ which
is supported on the front frame of the vehicle in a
conventional manner, not shown. The main case defines
a forwardly facing opening 60 for partly receiving and
guidably supporting the rear part of the multi-speed
transmission 14. ~ cylindrical access opening 62
defined in the main case at a rear wall 64 thereof is
adapted to closely receive a releasable annular access
plate 66. The access plate has a stepped cylindrical
bore 67 arranged on the upper axis 26 and a lube
passage 68 defined diametrically therethrough which is
in open communication with the bore and an upper lube
passage 70 defined in the main case. An intermediate
wall 72 integral with the main case supports a front
bearing assembly 74, and the access plate supports a
rear bearing assembly 76 upon which the input gear 24
is rotatably mounted. A tubular input shaft 78 serves
as the output of the transmission 14 and is selectively
driven through a range of speeds in either direction of
rotation. The tubular input shaft is connected to the
input gear 24 by a sliding spline connec~ion 80, and a
bearing assembly 82 serves to rotata~ly support the
engine driven input shaft 48 therewithin.
A coupling shaft 84 is releasably connected to
the distal end of the input shaft 48 by a sleeve
coupling 86. This sleeve coupling defines a plurality
of passages therein as identified generally by the
reference numeral 88 for distributing lubricating fluid
from the upper to the lower portions of passage 68
around the external periphery thereof and also for
directing a portion of the fluid rightwardly when
viewing Fig. 5 to lubricate the spline connection B0
and the bearings 74, 76 and 82.
The coupling shaft 84 extends leftwardly and
is splined to the second input gear 44 for continually
driving it at engine speed~ An axuiliary drive shaft
90 is also splined to the second input gear for
continually driving the hydraulic devices 50 such as a
gear pump 92 and an implenlent pump 94.
A secondary or auxiliary case 96 supports the
hydraulic devices 50, the second input gear 44 and the
PTO clutch 52. The auxiliary case is releasably
secured to the rear wall 64 of the main case 58 by a
plurality of fasteners ~8 located about the peripheral
front face thereof. A rearwardly disposed auxiliary
chamber 100 is thus defined between the auxiliary case
and the rear wall 64 of the main case and including the
access plate 66. One or more fluid passages 102
defined in the auxiliary case are aligned with
corresponding passages in the main case, such as the
distribution passage 68, so that fluid can be directed
rearwardly to the PTO clutch 52 for lubrication
purposes, or alternatively for the selective controlled
operation thereof in a conventional manner.
Xeferring now to the idler gear 34, it is
mounted on an opposed pair of tapered roller bearing
assemblies 104 sea'ed on a stepped cylindrical bearing
support element 106. The bearing support element
extends forwardly through a cylindrical opening 108
defined in the rear wall 64 of the main case 58 and
into engagement with a rearwardly facing blind bore 110
defined in the lower portion of the intermediate wall
72 of the main case. The bearing support element has a
plurality of interconnected passages 112 therein in
communication with the distribution passage 68 ~or
lubricating the bearings 104, and is releasably
connected to the main case by a threaded fastener 114.
Housing means 42 defines an enclosed
compartment 116 for containing the gear transfer train
22 and the drive line brake assembly 40 in juxtaposed
2~
_9_
relation and a common lubricating fluid therein. In
addition to the main case 58, the housing means
includes a sump housing 118, a brake body 120, and
internal wall means 122 for defining a rearwardly
disposed sump chamber 124 and a forwardly disposed
brake chamber 126 within the enclosed compartment l:L6.
The drive line brake assembly 40 is located
closely adjacent the output gear 28 within the brake
chamber 126/ and also serves to support the front end
of the output shaft 36~ More specifically, a
cylindrical opening or bore 128 concentric with the
lower axis 30 is defined in the wall 72 of the main
case 58. A peripheral flange 130 formed on the brake
body 120 is releasably connected to the wall 72 by a
pluLality of peripherally spaced and threaded fasteners
132, with a cylindrical surface 134 of the brake body
being pilotably received in the bore 128. The brake
body has a stepped bore 136 for supporting a tapered
roller bearing assembly 138 and a front seal ring 140.
In addition to the brake body 120, the drive
line brake assembly 40 includes a plurality of annular
plates and a plurality of annular discs identified
generally by the reference numeral 142 which are
alternatively connected to the brake body and to an
25 annular hub or drum 144. The output gear 28 is
provided with a forwardly extending, integral, and
externally splined sleeve 145, and the hub 144 is
releasably connected to the output gear 28 via the
splined sleeve. A front output flange 146 is
releasably connected to the output shaft by splines 14
and by the screwthreaded insertion of an end fastener
150 into the front end of the output shaft and against
a retaining plate 152. The output gear 28 and its
splined sleeve 145 are axially entrapped between a
shaft shoulder 154 and the inner race of the bearing
3~
--10--
assembly 138. The inner race of the bearing assembly
is urged axially to the left against another shaft
shoulder 155 a-t the front oE the spline connection 38
when the brake body 120 is installed against the wall
5 72 by tightening the fasteners 132 and biasing the
remainder of the bearing assembly in that direction.
The drive line brake assembly 40 further
includes an annular piston 156 which is selectively
urged to the left when viewing Fig. 5 via hydraulically
lO pressurized fluid communicated thereto by way of a
passage 158 in the brake body 120. When the piston
moves to the left it will clamp the interleaved plates
and discs 142 together as a unit against a reaction
plate 160 to stop rotation of the hub 144, the output
15 gear 28, and the output shaft 36 relative to the main
case 58. The piston is automatically retracted or
moved back to the right in a conventiona] manner by a
plurality of compression springs, not shown. One or
more passages 162 in the brake body 120 serve to direct
20 a preselected amount of lubricating fluid to the plates
and discs for dynamic cooling purposes.
The sump housing 118 defines a forwardly
facing opening 162 and an annular mounting flange 164.
The flange, and thus the sump housing, is releasably
25 connected to the rear wall 64 of the main case 58 by a
plurality of peripherally spaced fasteners 166. A
rearwardly located cylindrical opening 168 is defined
in the sump housing concentrically along the lower axis
30, and the output shaft 36 extends rearwardly through
30 the opening~ A tapered roller bearing assembly 170 is
releasably secured in place within the opening by an
annular retainer 172 so that the rear portion of the
output shaft is rotatably supported by the sump
housing. A rear flange 174 is releasably connected to
35 the output shaft via a spline 176, and a retaining
plate 178 and a fastener 180 releasably secure it in
place on the shaft while simultaneously holding the
inner race of the rear bearing assembly in proper
position against a shaft shoulder 1820 A rear seal
ring 184 is mounted radially between the rear flange
174 and the retainer 172 to contain lubricating fluid
within the enclosed compartment 116 much like the front
seal ring 140.
The wall means 122 may also include an annular
baffle element or baffle can 186 which is
advantageously utilized during running operation of the
vehicle 10 to minimize the amount of fluid in the brake
chamber 1~6 by directing access fluid to the sump
chamber 124. A rear end wall 188 of the baffle can is
releasably connected to the main case 58 by a plurality
of screwthreaded fasteners 190. As can also be
visualized with reference to both Figs. 2 and 5~ the
end wall 188 of the baffle can 186 has a rearwardly
projecting flanged sleeve portion 192 defining a
cylindrical opening 194 on the lower axis 30 for
closely receiving the output shaft 36 therethrough. An
annular seal 193 is seated within the sleeve portion of
the ba~fle can and sealingly engages a cylindrical
surface 195 defined on the output shaft 36. Thus the
seal restricts the direct transfer oE lubricating fluid
between the sump chamber 124 and the brake chamber 126.
As best shown in FigO 2 the baffle can 186 has
an upper gear access opening 196 for allowing the
baffle can to be mounted axially on the main case 58
after the idler gear 34 is installed. An outer
peripheral edge or front lip 198 of the baffle can is
entrapped between the cylindrical opening 128 in the
main case 58 and a cylindrical surface 200 formed in
-12-
the brake body 120 as is illus~rated more clearly in
Fig. 4. A seal member 202 is preferably connected to
the lip 198 to limit the transfer of fluid from the
sump chamber 124 into the brake chamber 126 at the
front end thereof. This seal member can be installed
by simply dipping the baffle can into a viscous sealing
material that can solely coat the lip.
Preferably, the baffle can 186 has a pair of
oppositely disposed fluid egress openings 204 defined
in the upper half thereof with a fluid deflecting edge
206 formed in the can at the upper part of each egress
opening as is illustrated in Fig. 3. Alternatively,
the baffle can could be more open at the top as by
combining the gear access opening 196 and the egress
openings 204 into one larger opening, not shownr as
long as the baffle can still would define a generally
U-shaped trough 208 as can be visualized by reference
to Figs. 2 and 5. The more enclosed baffle can o~ Fig.
2 is preferred, however, because a large proportion of
the lubricating fluid flowing down by gravity from the
upper portion of the gear transfer train 22 and from
the transmission 14 via the drain passage 209 will be
deflected toward the sump chamber 124 rather than
undesirably dropping into the brake chamber 126. In
the instant embodiment the output gear 28 is
conformingly received in the trough 208 in juxtaposed
relation to the drive line brake assembly 40.
Industrial Applicability
In operation, the transfer gear and drive line
brake mechanism 16 integrates a modularized and
serviceable wet drive line brake assembly 40 on the
Eront side of the main case 58 with a removable sump
housing 118 on the rear side of the main case. Upon
the release of the front flan~e 146, from the output
-13-
shaft 36 after the removal of fastener 150 and
retaining plate 152, the drive line brake assembly 40
can be removed from within the main case as a modular
unit independent of the output gear 28 and the baffle
element 186 by screwthreaded release of the fasteners
or bolts 132 and rightward movement of the brake body
120 when viewing Fiy. 5. Because the splined sleeve
145 is larger in diameter than the inner race and the
roller bearing elements of the front bearing assembly
138 it is advantageously not necessary to pull the
inner race and bearing elements during such
disassembly. Thus the outer race of the bearing
assembly, the plates and discs 142, and the brake hub
144 travel forwardly together with the brake body and
axially out~ardly of the output shaft 36 for convenient
servicing. By pulling the inner race of the bearing
assembly the output gear 28 can be subsequently moved
axially to the right along the spline connection 38 and
remcved from the output shaft allowing access to the
baffle can 186. Screwthreaded release of the fasteners
1~0 from the main case permits the rightward removal of
the baffle can from within the housing. The assembly
of these components is merely the reverse of this.
The baffle can 186 is of relatively economical
construction, being of formed metallic or plastic sheet
material. Yet it provides the major function of at
least partially surrounding the lower portions of the
ju~taposed output gear 28 and drive line brake assembly
40 in order to divide the common fluid compartment 116
into at least partially separated brake and sump
chambers 126,124. Specifically, during runniny
operation of the vehicle 10 the intermeshed gears 24,
34 and 28 are rotating and a preselected quantity of
lubricating fluid is ejected out of the opening 162 in
the brake body 120 to assure cooling of the brake
3ti'~
-14-
assembly 40. Rotation of the teeth of the output gear
28, however, adjacent the internal wall of the baffle
can is sufficient to urge any fluid collecting in the
trough 2~8 upwardly toward the egress opening 20~ as is
illustrated in Fig. 3. The rolled over or curved
deflecting edge 206 of the baffle can intercept this
fluid stream and redirect it radially outwardly of the
brake chamber 126 as is indicated by the arrow
identified by the letter A. During the reverse
10 operation of the vehicle the opposite egress openin~
performs the same function. Hence, the fluid level in
the brake chamber is maintained at a relatively low
level near the bottom of the output gear to effectively
reduce fluid drag losses. At the same time the fluid
level in the sump chamber can be much higher such as
being at the approximate elevation of the lower axis 30.
Thus, the mechanism of the present invention
shares a common lubricating fluid compartment for a
plurality of components including the auxiliary drive
20 means 46 for powering the hydraulic devices 50 and the
PT0 clutch assembly 52. Fluid from these components
can drain from the auxiliary chamber 100 back into the
main case 58 via one or more drain passages 210 for
example. Moreoever, the drive line brake assembly 40
can be relatively continuously lubricated in order to
extend its capacity and service life, and yet the fluid
drag losses that would normally be associated with a
plurality of plates and discs 142 churning -through a
relatively high fluid level are greatly reduced by
30 means of the baffle can 186. The gear or transmission
pump 92 draws fluid continually from the sump chamber
124 via an intake pipe and filter assembly, not shown
but of conventional construction, during operation of
the vehicle 10 to complete the circulatory system.
Other aspects, objects and advantages will
become apparent from a study of the specification,
drawings and appended claims.
~5
