U.S. patent application number 09/733103 was filed with the patent office on 2002-06-13 for transmission on all wheel steer power machine.
Invention is credited to Knutson, Donald, Krause, Charles H., Weber, Kenneth R..
Application Number | 20020070058 09/733103 |
Document ID | / |
Family ID | 24946243 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070058 |
Kind Code |
A1 |
Knutson, Donald ; et
al. |
June 13, 2002 |
TRANSMISSION ON ALL WHEEL STEER POWER MACHINE
Abstract
A transmission in a power machine includes an axle having an
inboard and outboard end. The outboard end is coupled to a wheel
through a universal joint. The inboard end is coupled, through a
sprocket assembly and chain drive linkage to a hydraulic motor. The
axle is supported at its inboard end by a single spherical
bearing.
Inventors: |
Knutson, Donald; (Gwinner,
ND) ; Krause, Charles H.; (Hankinson, ND) ;
Weber, Kenneth R.; (Milnor, ND) |
Correspondence
Address: |
NATHAN M RAU
WESTMAN, CHAMPLIN & KELLY, P.A.
900 SECOND AVENUE SOUTH
MINNEAPOLIS
MN
55402-3319
US
|
Family ID: |
24946243 |
Appl. No.: |
09/733103 |
Filed: |
December 8, 2000 |
Current U.S.
Class: |
180/6.44 ;
180/23 |
Current CPC
Class: |
B60K 17/00 20130101;
B60K 17/30 20130101; B60K 17/22 20130101; B60K 17/342 20130101;
B62D 11/04 20130101; B60K 17/358 20130101; B62D 7/142 20130101 |
Class at
Publication: |
180/6.44 ;
180/23 |
International
Class: |
B62D 011/00 |
Claims
What is claimed is:
1. A power vehicle transmission transmitting a drive output from a
hydraulic motor mounted to a body of a vehicle to a wheel, the
transmission comprising: a sprocket assembly adapted to receive a
drive input from a motor driven chain; an axle rigidly coupled to
the sprocket assembly, the axle having an inboard end and an out
board end; a single spherical bearing coupling the inboard end of
the axle to the body of the vehicle; a universal joint coupled to
the outboard end of the axle; and a wheel hub coupled to the
universal joint.
2. The transmission of claim 1 wherein the sprocket assembly
comprises: a sprocket having a central region and an outer
periphery, the outer periphery being adapted to receive the chain;
and a sleeve rigidly coupled about the inboard end of the axle and
rigidly coupled to the central region of the sprocket.
3. The transmission of claim 2 wherein the axle includes an annular
shoulder thereon and wherein the spherical bearing abuts an
outboard side of the annular shoulder and is disposed about the
axle inboard of the sleeve.
4. The transmission of claim 3 and further comprising: a retaining
ring disposed between the outboard side of the spherical bearing
and the inboard side of the sleeve.
5. The transmission of claim 3 wherein the sleeve is coupled to the
axle by a spline.
6. The transmission of claim 5 wherein the sprocket assembly
further comprises: an end cap rigidly coupled to the outboard end
of the axle retaining the sleeve thereon.
7. The transmission of claim 2 and further comprising: a yoke
rigidly coupled to the outboard end of the axle.
8. The transmission of claim 7 wherein the yoke is rigidly coupled
to the axle with a spline.
9. The transmission of claim 7 and further comprising: an axle tube
disposed about the axle over substantially an entire length of the
axle.
10. The transmission of claim 9 wherein the axle tube is rigidly
coupled to the body of the vehicle and further comprising: a seal
disposed about the outboard end of the axle and disposed about a
portion of the yoke.
11. The transmission of claim 1 and further comprising: a steering
element coupled to the body of the vehicle and an outboard end of
the universal joint to steer the wheel.
12. The transmission of claim 11 wherein the steering element
comprises: a hydraulic cylinder having a rod end and a base end and
a plurality of hose couplings.
13. The transmission of claim 12 wherein the body portion comprises
a chain case and wherein the hydraulic cylinder is coupled to the
chain case such that the base end and all of the hose couplings are
mounted within an interior portion of the chain case and such that
the rod end of the hydraulic cylinder extends outside the chain
case.
14. A power machine having a body, comprising: a chain case coupled
to the body; at least one hydraulic motor coupled to the chain
case; a plurality of independently steerable and rotatable wheels;
a plurality of steering elements each coupled to one of the wheels
and one of the chain case and the body; a plurality of
transmissions each coupled to one of the wheels and the at least
one hydraulic motor, each of the transmissions comprising: a
sprocket assembly including a chain; an axle rigidly coupled to the
sprocket assembly, the axle having an inboard end and an out board
end; a single spherical bearing coupling the inboard end of the
axle to the body of the vehicle; a universal joint coupled to the
outboard end of the axle; and a wheel hub coupled to the universal
joint.
15. The power machine of claim 14 wherein the steering element
comprises: a hydraulic cylinder having a rod end and a base end and
a plurality of hose couplings.
16. The power machine of claim 15 wherein the hydraulic cylinder is
coupled to the chain case such that the base end and all of the
hose couplings are mounted within an interior portion of the chain
case and such that the rod end of the hydraulic cylinder extends
outside the chain case.
17. The power machine of claim 14 wherein the sprocket assembly
comprises: a sprocket having a central region and an outer
periphery, the outer periphery being adapted to receive the chain;
and a sleeve rigidly coupled about the inboard end of the axle and
rigidly coupled to the central region of the sprocket.
18. The power machine of claim 17 wherein the axle includes an
annular shoulder thereon and wherein the spherical bearing abuts an
outboard side of the annular shoulder and is disposed about the
axle inboard of the sleeve.
19. The power machine of claim 14 wherein the plurality of wheels
comprise four wheels and wherein the at least one hydraulic motor
comprises two hydraulic motors each coupled to a pair of the four
wheels.
20. A power machine having a body, comprising: a chain case coupled
to the body; at least one hydraulic motor coupled to the chain
case; a plurality of independently steerable and rotatable wheels;
a hydraulic cylinder having a rod end and a base end and a
plurality of hose couplings, the hydraulic cylinder being coupled
to the chain case such that the base end and all of the hose
couplings are mounted within an interior portion of the chain case
and such that the rod end of the hydraulic cylinder extends outside
the chain case; and a plurality of transmissions each coupled to
one of the wheels and the at least one hydraulic motor.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to transmissions for
power machines. In particular, the present invention relates to a
transmission on a power machine with a spherical bearing.
[0002] Power machines, such as loaders, typically have a number of
power actuators. Such actuators can include, for example, drive
actuators or motors which provide traction power to the wheels or
tracks of the machine. The actuators can also include those
associated with manipulating a primary working tool, such as a
bucket. In that case, the actuators include lift and tilt
actuators. Of course, a wide variety of other actuators can also be
used on such power machines. Examples of such actuators include
auxiliary actuators, hand-held or remote tool actuators or other
actuators associated with the operation of the power machine
itself, or a tool coupled to the power machine.
[0003] The various actuators on such power machines have
conventionally been controlled by mechanical linkages. For example,
when the actuators are hydraulic actuators controlled by hydraulic
fluid under pressure, they have been controlled by user input
devices such as handles, levers, or foot pedals. The user input
devices have been connected to a valve spool (of a valve which
controls the flow of hydraulic fluid under pressure to the
hydraulic actuator) by a mechanical linkage. The mechanical linkage
transfers the user input motion into linear displacement of the
valve spool to thereby control flow of hydraulic fluid to the
actuator.
[0004] Electronic control inputs have also been developed. The
electronic inputs include an electronic sensor which senses the
position of user actualable input devices (such as hand grips and
foot pedals). In the past, such sensors have been resistive-type
sensors, such as rotary or linear potentiometers.
[0005] In the past, transmissions have included chain drive
transmissions. A hydraulic motor has been coupled to an axle
through a sprocket, via a chain linkage. Rotation of the hydraulic
motor drives rotation of the axle and consequent rotation of the
wheels. However, past transmissions have been configured such that
the inboard end of the axle is supported inside a differential by a
tapered roller bearing arrangement. Other transmissions have
included two sets of bearings. An inboard and an outboard set of
bearings are configured relative to the axle to handle both axial
and radial loads on the axle.
SUMMARY OF THE INVENTION
[0006] A transmission in a power machine includes an axle having an
inboard and outboard end. The outboard end is coupled to a wheel
through a universal joint. The inboard end is coupled, through a
sprocket assembly and chain drive linkage, to a hydraulic motor.
The axle is supported at its inboard end by a single spherical
bearing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a side elevational view of a power machine in
accordance with one embodiment of the present invention.
[0008] FIG. 2 is a perspective view illustrating a transmission of
the power machine shown in FIG. 1, with the motor and portions of
the chain case removed for the sake of clarity.
[0009] FIG. 3 is a more detailed view of one portion of the
transmission shown in FIG. 2.
[0010] FIG. 4 is a more detailed view of a portion of the
transmission shown in FIG. 3, with portions shown in cross
section.
[0011] FIG. 5 is a more detailed view of a sprocket assembly shown
in FIG. 4, in cross section.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
[0012] FIG. 1 is a side elevational view of one embodiment of a
loader 10 according to the present invention. Loader 10 includes a
frame 12 supported by wheels 14. Frame 12 also supports a cab 16
which defines an operator compartment and which substantially
encloses a seat 19 on which an operator sits to control skid steer
loader 10. A seat bar 21 is optionally pivotally coupled to a front
portion of cab 16. When the operator occupies seat 19, the operator
then pivots seat bar 21 from the raised position (shown in phantom
in FIG. 1) to the lowered position shown in FIG. 1.
[0013] A pair of steering joysticks 23 (only one of which is shown
in FIG. 1) are mounted within cab 16. Joysticks 23 are manipulated
by the operator to control forward and rearward movement of loader
10, and in order to steer loader 10.
[0014] A lift arm 17 is coupled to frame 12 at pivot points 20
(only one of which is shown in FIG. 1, the other being identically
disposed on the opposite side of loader 10). A pair of hydraulic
cylinders 22 (only one of which is shown in FIG. 1) are pivotally
coupled to frame 12 at pivot points 24 and to lift arm 17 at pivot
points 26. Lift arm 17 is coupled to a working tool which, in this
embodiment, is a bucket 28. Lift arm 17 is pivotally coupled to
bucket 28 at pivot points 30. In addition, another hydraulic
cylinder 32 is pivotally coupled to lift arm 17 at pivot point 34
and to bucket 28 at pivot point 36. While only one cylinder 32 is
shown, it is to be understood that any desired number of cylinders
can be used to work bucket 28 or any other suitable tool.
[0015] The operator residing in cab 16 manipulates lift arm 17 and
bucket 28 by selectively actuating hydraulic cylinders 22 and 32.
In prior loaders, such actuation was accomplished by manipulation
of foot pedals in cab 16 or by actuation of hand grips in cab 16,
both of which were attached by mechanical linkages to valves (or
valve spools) which control operation of cylinders 22 and 32.
However, this actuation can also be accomplished by moving a
movable element, such as a joystick, foot pedal or user actuable
switch or button on a hand grip or joystick 23 and electronically
controlling movement of cylinders 22 and 32 based on the movement
of the movable element. In one embodiment, movement of the movable
elements is sensed by a controller in the hand grip and is
communicated to a main control computer used to control the
cylinders and other hydraulic or electronic functions on a loader
10.
[0016] By actuating hydraulic cylinders 22 and causing hydraulic
cylinders 22 to increase in length, the operator moves lift arm 17,
and consequently bucket 28, generally vertically upward in the
direction indicated by arrow 38. Conversely, when the operator
actuates cylinder 22 causing it to decrease in length, bucket 28
moves generally vertically downward to the position shown in FIG.
1.
[0017] The operator can also manipulate bucket 28 by actuating
cylinder 32. This is also illustratively done by pivoting or
actuating a movable element (such as a foot pedal or a hand grip on
a joystick or a button or switch on a handgrip) and electronically
controlling cylinder 32 based on the movement of the element. When
the operator causes cylinder 32 to increase in length, bucket 28
tilts forward about pivot points 30. Conversely, when the operator
causes cylinder 32 to decrease in length, bucket 28 tilts rearward
about pivot points 30. The tilting is generally along an arcuate
path indicated by arrow 40.
[0018] While this description sets out many primary functions of
loader 10, a number of others should be mentioned as well. For
instance, loader 10 may illustratively include blinkers or turn
signals mounted to the outside of the frame 12. Also loader 10 may
include a horn and additional hydraulic couplers, such as front and
rear auxiliaries, which may be controlled in an on/off or
proportional fashion. Loader 10 may also be coupled to other tools
which function in different ways than bucket 28. Therefore, in
addition to, or instead of, the hydraulic actuators described
above, loader 10 may illustratively include many other hydraulic or
electronic actuators as well.
[0019] In one illustrative embodiment, loader 10 is an all-wheel
steer loader. Each of the wheels is both rotatable and pivotable on
the axle on which it is supported. Pivoting movement can be driven
using a wide variety of mechanisms, such as a hydraulic cylinder,
an electric motor, etc. For the sake of clarity, the present
description will proceed with respect to the wheels being
individually steered with hydraulic cylinders.
[0020] In addition, loader 10 illustratively includes at least two
drive motors, one for the pair of wheels on the left side of the
vehicle and one for the pair of wheels on the right side of the
vehicle. Of course, loader 10 could also include a single drive
motor for all four wheels, or a drive motor associated with each
wheel.
[0021] By moving or pivoting the handgrip or a set of steering
levers located in the operator's compartment, the operator controls
the hydraulic motors. In doing so, the operator controls both
direction of rotation of the motors, and motor speed. This allows
the operator to control the fore/aft movement of the loader, as
well as loader direction and speed.
[0022] FIG. 2 is a perspective view of a portion of loader 10, with
the upper portion of loader 10 removed exposing only a chasis or
structural body portion 100 as well as a chain case 102. FIG. 2
also illustrates four transmission assemblies 104, 106, 108 and 110
which are used to drive rotation of wheels 14 on loader 10. FIG. 2
also illustrates a motor 112 diagrammatically. It will be
appreciated that motor 112 is illustratively a hydraulic motor
connected through aperture 114 in chain case 102. Motor 112
illustratively includes a rotatable output drive shaft and sprocket
assembly which is connected to a corresponding sprocket assembly on
a corresponding transmission by a chain drive linkage
diagrammatically illustrated by arrow 116. It will also be
appreciated that from one to four motors 112 can be provided on
loader 10 such that a single motor drives all wheels or such that
some of the wheels are individually driven pr are driven in pairs.
For the sake of clarity, only a single motor 112 is
diagrammatically shown in FIG. 2. Transmissions 104-110 are
illustratively substantially identical to one another. Therefore,
the present description will proceed only with respect to
transmission 108.
[0023] Transmission 108 includes an outboard end 120 and an inboard
end 122. Outboard end 120 includes a tire mounting hub 122, a
universal joint 124, and a steering connection tab 126. Inboard end
122 includes a sprocket assembly 128 which is described in greater
detail with respect to FIGS. 35. The inboard end 122 is connected
to the outboard end 120 by an axle assembly 130. Axle assembly 130
is also discussed in greater detail with respect to FIGS. 3-5.
[0024] In order to steer the tires mounted on hub 123 a hydraulic
cylinder 131 is coupled at a pivot axis 132 on chain case 102 and
to steering tabs 126 on universal joint 124. In one illustrative
embodiment, hydraulic cylinder 131 has its base end, and all hoses
and hose couplings, on the interior of structural body member 100,
and only the rod end of cylinder 131 extends through an aperture
133 in structural body member 100 to connect to tabs 126.
[0025] Cylinder 131 is illustratively connected to a hydraulic
power system in loader 10 which provides hydraulic fluid under
pressure to the base and rod ends of cylinder 131 through the hoses
and couplings to lengthen or shorten the cylinder, respectively.
The valves controlling provision of hydraulic fluid under pressure
to cylinder 131 are illustratively controllable by user inputs
located within the operator compartment of loader 10. When the
operator causes cylinder 131 to be lengthened or shortened, this
consequently causes the wheel mounted to hub 123 to be turned in
opposite directions at universal joint 124.
[0026] FIG. 3 is a more detailed view of transmission 108 with the
chain case and a portion of universal joint 124 removed, and also
with an outer axle tube (which surrounds the axle) removed. These
items have been removed for the sake of clarity. FIG. 3 also
illustrates a portion of transmission 104 as it is disposed
relative to transmission 108, when mounted to the chain case.
[0027] FIG. 3 illustrates that axle assembly 130 includes an axle
140, itself having an outboard end 142 and an inboard end 144.
Outboard end 142 has a splined end which frictionally engages
female yoke 144. The outboard end of female yoke 144 is surrounded
by a seal 146 which seals the internal connection portions of
universal joint 124. A portion of universal joint 124 is also shown
in FIG. 3.
[0028] In one illustrative embodiment, universal joint 124 includes
a simple Hooke's joint, or Cardan joint. In such an embodiment,
yoke 144 is attached to yoke 148 (which has a splined outboard end
150 adapted to receive hub 123 thereabout) by a spider which
includes coupling members 150 and 152.
[0029] The inboard end 144 of axle 140 illustratively includes a
shoulder 154 formed thereon. Of course, shoulder 154 can be an
annular ring which is welded to the external periphery of the
outboard end 144 of axle 140, or shoulder 154 can be integrally
formed with axle 140. In any case, shoulder 154 acts as a positive
stop for spherical bearing 156.
[0030] Spherical bearing 156 illustratively includes an internal
longitudinal bore for fitting over the external periphery of axle
140. Drive sprocket 160 is coupled to the end of axle 140 and is
secured on the end of axle 140 by an end cap 162 which is, itself,
secured on the end of axle 140 by a screw. This assembly is
illustrated in greater detail in FIGS. 4 and 5. Therefore, rotation
of drive sprocket 160, in turn, causes rotation of axle 140 within
spherical bearing 156. This also causes rotation of yoke 144 within
seal 146, and consequently causes rotation of coupling member 150
in universal joint 124. This, of course, in turn transmits the
rotation of axle 140 into rotation of yoke 148 and consequent
rotation of the tire mounted to yoke 148.
[0031] FIG. 4 is a more detailed illustration shown in partial
cross section. FIG. 4 shows, in greater detail, that yoke 148 is
connected to yoke 144 through a spider in universal joint 124. Yoke
148 is, in turn, securely connected to hub 123 which is adapted for
a mounting of a tire thereon. Yoke 144 is, of course, rigidly
coupled to axle 140 through a spline. It should also be noted, in
one illustrative embodiment, mounting tabs 126 (shown in FIG. 2)
are mounted to an exterior portion 170 of a housing which houses a
portion of universal joint 124. This allows yoke 148 (and
consequently hub 123) to be pivoted, about axis 172, in order to
steer the wheel mounted on hub 123.
[0032] FIG. 4 also illustrates that axle 140 is substantially
enclosed by an axle tube 174. The outboard end of axle 174 has a
housing member 176 attached thereto. Housing member 176 serves to
further enclose universal joint 124. Yoke 144 is rotatably mounted
within housing member 176 and the internal portion of universal
joint 124 is sealed with a seal 178, which is illustratively any
seal suitable for sealably receiving a rotatable member.
[0033] Axle tube 174 is also disposed through an aperture in
structural body member 100 to position axle 140 at a desired
location relative to structural body member 100.
[0034] FIG. 4 further illustrates that the inboard end of axle 140
has spherical bearing 156 mounted thereabout. In the embodiment
illustrated in FIG. 4 shoulder 154 which holds spherical bearing
156 from migrating in the outboard direction along axle 140 is
simply an integral shoulder integrally formed on the outer
periphery of axle 140. Similarly, spherical bearing 156 is held in
place, from migrating in the inboard direction along axle 140, by a
clamp 180 which is rigidly coupled to drive sprocket 160. Clamp 180
can illustratively be coupled to drive sprocket 160 by inertial
welding, or by any other suitable technique for rigidly coupling
drive sprocket 160 to clamp 180. Clamp 180 is connected to the
extreme inboard end of axle 140 by a spline arrangement. Clamp 180
is held in place on the spline, illustratively by a frictional fit,
or by end cap (or washer) 162 which can also be connected to the
inboard end of axle 140 by inertial welding, or it can be held in
place by a bolt or screw 182, or both. Of course, drive sprocket
160 can be connected to axle 140 by any other suitable means as
well.
[0035] It should also be noted that, in one illustrative
embodiment, spherical bearing 156 is held in place by an additional
retaining ring 184 as well. Retaining ring 184 can be welded to the
inside of axle tube 174, or it can be welded or otherwise connected
to the exterior periphery or the end of clamp 180. In any case,
retaining ring 184 is illustratively provided in the assembly
shown.
[0036] FIG. 5 is a more detailed illustration of the sprocket
assembly and spherical bearing. FIG. 5 more clearly shows that
spherical bearing 156 is illustratively a spherical roller bearing
which includes two rows of rollers 190 and 192 which have a common
sphered outer raceway 194 and two inner ring raceways 196 and 198
which are inclined at an angle to the bearing axis. Thus, spherical
bearing 156 is self aligning in that misalignment between axle 140
and the bearing housing can be accommodated. The bearing is thus
insensitive to angular misalignment of the shaft with respect to
the housing or to shaft bending during operation. Also, of course,
such a spherical roller bearing is illustratively particularly
suitable for carrying combined (radial and axle) loads. This
provides significant advantages over the use of two single angular
contact spherical plan bearings. In order to accommodate both
radial and axle loads, such bearings must usually be adjusted
against one another and arranged such that their sphere centers
coincide. However, by using only a single spherical bearing 156,
neither a differential is required, nor is a set of single angular
contact bearings.
[0037] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention
* * * * *