Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Description
Seal and Seal Assembly
Technical Fie_
The invention relates to a seal and seal
assembly. More particularly, the invention relates to
a leg of a seal which is controllably deflectable and
has first and second sealing areas in slidable contact
with substantially perpendicular surfaces in the seal
assembly.
Ba~round Art
In the use of a seal and seal assembly, it is
desirable to block passage of foreign matter in one
direction but to permit deflection of the seal in
another direction to, for example, allow overfilling a
bearing wi-th lubricant to clean the bearing.
U.S. Patent 4,043,620 which issued to Otto on
August 23, 1977, discloses configurations of bearing
seals used to seal openings between a housing and a
rotatable shaft.
U.S. Patent 3,687,464 which issued to Jackson
et al on August 29, 1972, discloses a seal which has a
U-shaped cross-section and is used to seal against a
shaft and a housing perpendicularly oriented to the
shaft. U.S. Patent 3,841,723 which issued on October
25, 15, 1974, to Kelso shows a seal having a dust lip and a
spring biased seal lip.
For example, a steering assembly for a work
vehicle commonly includes an axle or frame mounted king
pin about which a steering knuckle is rotatable.
Rotation of the steering knuckle provides corresponding
rotation of a spindle to controllably turn a wheel of
the vehicle attached thereto. The steering knuckle is
-2-
supported about the king pin by a bearing which must be
protected and periodically lubricated to assure proper
performance of the steering assembly.
The bearing is exposed to the environment of
the work vehicle through an opening loca~ed between the
steering knuckle and axle owing to the relative rota-
tion of the two components. Heretofore, a seal having
two lips or legs and being connected to the steering
knuckle has been used. The two lips contact or seal
against a surface on the frame or axle to block passage
of foreign matter to the bearing. However, when lubri-
cant is subsequently injected into the bearing said
seal also blocks passage of the lubricant out of the
bearing. In situations where the bearing is over-
filled, such as to drive old lubricant from thebearing, this can cause damage to the seal or improper
performance of the steering assembly. The result is a
waste of time and labor owing to the reduced perfor-
mance of the steering assembly or downtime in replacing
the seal.
Therefore, it is desirable to provide a seal
which blocks passage of foreign matter in one direc-
tion, such as to the bearing, and controllably deflects
in another direction to permit lubricant overfill of
the bearing to relieve for substantially preventing
damage to the seal as a result of the overfill.
Disclosure of Invention
In one aspect of the present invention, a seal
comprises a body; a leg having first, second and third
sides, a middle portion and first and second end por-
tions and being connec-ted at the first end portion to
the body, the first side being in cross-section
straight along its full length and generally opposed to
the second side, the second side having in cross-
- section a straight portion intersecting the third side
'~,
-3
and oriented to extend parallel to the first side along
the full length of the first side and an arcuate por-
tion defining an arcuate surface extending curviline-
arly inwardly in a direction generally toward the first
side and defining a reduced cross-sectional area of the
leg at the middle portion relative to the second end
portion, the third side being in cross~section straight
along its full length and intersecting the first and
second sides at the second end portion~ the second end
portion being controllably deflectable relative to the
first end portion in response to a force exerted on at
least one of the first and third sides; and first and
second sealing areas positioned on the leg adjacent the
intersection of the first and third sides, and the
15 intersection of the second and third sides, ::
respectively.
Brief Description of Drawings
FIG. 1 is a diagrammatic view showing one
embodiment of the seal assembly of the present inven-
tion associated with a steering mechanism;
FIG. 2 is a diagrammatic partial view of FIG.
1 showing the invention in greater detail;
FIG. 3 is a aiagrammatic cross-sectional view
showing one embodiment of the seal of the present
invention; and
FIG. 4 is a diagrammatic view showing another
embodiment of the seal and seal assembly of the present
invention associated with the steering mechanism.
. ,,~ . ~
: .
. `
Best Mode for Carrying Out the Inven-tion
Referring to FIG. 1, a seal assembly 10
includes first and second members 12,14 ro-tatable one
relative to the other and a seal 16. The first member
'2 is, for example, a frame portion 20 of a work vehicle
21. Said frame portion 20 includes an axle 22, king
pin 24 and a spacer 26. The second member 14 is, for
example, a s-teering knuckle 27 of the work vehicle
which is positioned adjacent said frame portion 20. The
steering knuckle 27 is rotatable about the fixed frame
portion 20 in response to input forces exerted in
steering the work vehicle 21. Means 28, shown as
a bearing 30, is provided for supporting said ~rame
portion 20 and the steering knuckle 27 in rotation one
relative to the other. Such wheel steering construction
is well known in the vehicle art.
The frame portion 20 has first and second
surfaces 32,34 oriented substantially perpendicular one
relative to the other and defined by the spacer 26 and
axle 22, respectively. The frame portion 20 and steer-
ing knuckle 27 define an annular opening 36 between
said steering knuckle 27 and sald first and second
surfaces 32,34. The seal 16 in the seal assembly 10
is annular in configuration and is positioned at a
location sufficient for controllably sealing the passage
of material through said annular opening 36 as will be
hereinafter described.
Referring particularly to FIG. 3~ the seal
16 includes a body 38, a leg 40 and first and second
30 sealing areas 42,44. The leg 40 has first, second and
third sides 46,48,50, first and second end portions
52,~4 and a middle portion 56. Said leg 40 is connected
at the first end portion 52 to the body 38 and extends
outwardly from said body 38. The first and second
sides 46,48 are substantially linear, and generally
~B~4~
--5--
opposed one to the other. The third side 50 intersects
the first and second sides 46,48 at the second end
portion 54 preferably at respective angles ~1,A2 o~
about 90~. Said seal 16 preferably has only a single
leg 40 as shown.
The first and second sealing areas 42,44 are
each positioned on the leg 40 adjacent the intersection
of the first and third s~des 46,50 and the intersection
of the second and third sides 48,50, respectively. Said
sealing arèas 42,44 are preferably located at or formed
by the intersection of the first and thixd sides 46,50
and the second and third sides 48,50 respectively.
The second end portion 54 of the leg 40 is
of a construction suffic~ent for being controllably
deflectable relative to the first end portion 52 in
response to a force exerted on at least one oE the
first and third sides 46,50 of the leg 40. In the
embodiment shown, the second side 48 of the leg 40,
which is generally opposed to the first side 46, is of
a configuration sufficient for defi~ing a reduced
cross-sectional area of said leg 40 at the middle
portion 56 relative to said second end portion 54. The
reduction in cross-sectional area, as further defined
below by the configuration of said second side 48,
provides controllable deflection of the second end
portion 54 for the purposes hereinafter discussed.
The second side 48 of the leg 40 has an
arcuate surface 58 extending curvilinearly inwardly on
said leg 40 from the second end portion 54 toward the
middle portion 56 in a direction generally toward the
first side 46. The leg 40 has a width at Wl defined by
the distance between the first and second sides 46,48
and the arcuate surface 58 extends inwardly at the
middle portion 56 about one-half of said width (shown
at W2). In other words, the second side 48 extends
curvilinearly inwardly and progressively reduces the
' .
--6--
cross-sectional area of the second leg 40 from the
second end portion 54 toward the middle portion 56.
Thus, the cross-sectional area adjacent W2 is less than
the cross-sectional area adjacent Wl. It is also
desirable that said arcuate surface 58 further extend
curvilinearly outwardly from the middle portion 56
toward the first end portion 52 of the leg 40 in a
direction from the ~irst side 46 and intersect the body
38 at a location 60 at which the leg 40 connects at the
second side 48 to the body 38.
The second side 48 has an arcuate portion 62
defining the arcuate surface 58 of said second side 48
and a substantially linear portion 64 intersecting the
third side 50 of the leg 40 and which is preferably
substantially parallel to the first side 46 of said leg
40. Said linear portion 64 has a length (~1) about
one-third the length L2 of the first side 46 in order
to maintain sufficient width at the second end portion
54 of the leg 40 for adequate rigidity of the seal 16
in position in the seal assembly 10 against the first
and second surfaces 32,34 of the frame portion 20.
Further, the first sealing area 42 is positioned on the
leg 40 at a location immediately adjacent a point 66 on
. the second side 48 from which the arcuate surface 58
extends inwardly toward the first side 46.
Referring to the embodiment of FIG. 4, means
63 is provided for biasing the second end portion 54 of
the leg 40 relative to the first end portion 52 of said
leg 40 in a direction Dl from the second side 48 toward
the first side 46 of the leg 40. Said biasing means 63
is shown as a spring 65, such as a helica1 spring,
positioned on the second side 48 of the leg 40 and
retained in a groove 67 formed in the arcuate portion
62 of said second side 48. In an annular configuration
of the seal 16, which is the preferred embodiment, the
spring 65 tends to bias outwardly against and about
. : ' ' ' ,
`" 7
said second side 48 to urge said first and second
sealing areas 42,44 into contact with the first and
second surfaces 32,34 when the seal 16 is posi~i~ned in
the seal assembly 10. Said biasing means 63 can also
be, for example, a ring or similar element which tends
to expand outwardly against the second side 48.
q'he body 38, leg 40 and first and second
sealing areas 42,44 are preferably o~ unitary, elasto-
meric construction. The seal 16 also has a carrier
element 68 connected or molded to the body 38 o~ at
least first and second sides 70,72 of said body 40.
The carrier element 68 is of metallic construction as
is known in the art. The first and second sides 46,50
of the leg 40 intersect third and fourth sides 74,76 of
the body 38 and define the orientation of the leg 40
relative to the body 38 as shown. It should be under-
stood that the seal 16 can be of other conflgurations
as is known in the art without departing from the
invention.
In the installed position of the seal 16 in
the seal assembly 10, the seal body 38 is connected to
the steering knuckle 27 and positioned adjacent and
extending about the annular opening 36. In the embodi-
ment shown, said seal 16 is press fit into a substan-
tially circular bore 77 defined by the steering knuckle
27 owing to the oversize configuration of the metallic
carrier element 68. The first sealing area 42 is
positioned in sealing, slidable contact with the first
surface 32 of the frame portion 20. The second sealing
surface 44 is positioned in sealing slidable contact
with the second surface 34 of the frame portion 20. It
is desirable that the second end portion 54 of the leg
40 be controllably deflectable as above described with
respect to the individual seal 16. ~he first and
second sealing areas 42/44 are thus removable from
contact with the first and second surfaces 32,34,
--8--
respectively, in response to controllably deflectiny
the second end portion 54.
A line 78 passing between the first and
second sealing areas 42,44 intersec~s the first surface
32 of the frame portion 20 at an angle A5 in a range of
about 45 to about 90. The third side 50 extends be-
tween said sealing areas 42,44 and defines said line
78. The angle A~ in the preferred embodiment is about
45. In other words, said line 78 passing between the
sealing areas 42,44 defines a chord 80 of a circle 82
having a radial line 84. The radial line 84 substan-
tially bisects the chord 80 and passes immediately
adjacent the intersection 86 of first and second planes
32',34' defined bv the first and second surfaces 32,34
of the frame portion 20. As is also shown, the first
side 42 of the leg 40 intersects the Eirst surface 32
of the frame portion 20 at an angle A6 of about 60.
The linear portion 64 of the second side 44 intersects
the second surface 34 of the frame portion 20 at an
angle ~7 of about 60.
It is desirable that the first and second
sealing areas 42,44 urge against the first and second
surfaces 32,34 of the frame portion 20, respectively,
in order to maintain a positive "seal" against said
surfaces 32,34. The biasing means 65 or spring 67 in
the embodiment of FIG. 4 biases the second end portion
54 of the leg 40 relative to the first end portion 52
of the leg 40 in a direction D2 toward the first surface
32 of the frame portion 20 to assure the positive
3a "seal". Said direction D2 is shown substantially the
same as the direction Dl. The positive "seal" can also
be assured by preloading the leg 40. In o-ther words,
the orientation of the first side 46 of the leg 40, as
represented by angle A3~ (FIG. 3) can be provided in
the seal 16 such that said first side 46 is displaced
~rom said angle A3 to an installation angle A4 (FIG. 2)
- 9 -
when the seal 16 is in the installed position. Thus,
angle A3 is provided less than angle A4 to establish
t~e preloaded condition.
On the sealed assembly 10, the leg 40 forms
an annular chamber 88 with the frame portion 20. The
annular chamber 88 is defined by the first and second
surfaces 32,34 of said frame portion 20 and the third
side 50 of the leg 40. The leg 40 also forms ~irst and
second channels 90,92 with said frame portion 20. Said
first and second channels 90,92 are defined by the
first side 42 of the leg 40 and the first surface of
the frame portion 20 and the second side 44 of the leg
40 and the second surface 34 o the frame portion 20,
respectively. Said channels 90,92 are of a construc-tion
suficient for being positionable in communication one
with the other in response to removing the first and
second sealing areas 42,44 from contac-t with the first
and second surfaces 32,34 respectively.
It is desirable that in the seal assembly 10
the second end portion 54 of the leg 40 be controllably
deflectable relative to the first end portion 52 of the
leg 40, as was explained previously with respect to the
seal 16. Also, the configuration of said seal 16 is
preferably also as above explained with respect to the
seal 16. The first and second sealing areas 42,44 are
removable from contact with the first and second surfaces
32,34 of the frame portion 20, respectively, in response
to controllably deflecting said second end portion 54,
as is shown by way of example in FIG. 1. The channels
90,92 are in fluid con~unication one with the other in
response to exerting a force on at least one of the
first and third sides 46,50 of the leg 40 for deflecting
said second end portion 54.
It should be understood that the seal 16 and
seal assembly 10 can be of other configurations as is
known in the art without departing from the invention.
--10--
Industrial Applicabilit~v
In the use of -the seal 16 in the seal assembly
10, the first and second sealing areas 42,44 slidably
contact the first and second surfaces 32,3~ of the
frame portion 20 to block passage of foreign matter
through the annular opening 36 and to the bearing 30.
Overfill of lubricant in the bearing 30 controllably
deflects the second end portion 54 of the leg 40 to
relieve lubricant through the annular opening 36 to
clean the bearing 30.
For example, input forces on the steering
knuckle 27 through a steering arm 93 cause said knuckle
27 to rotate relative to the frame portion 20. In
rotation the first and second sealing surfaces 42,44
wipe or slide along the frame portion 20 to prevent
passage of di~t, water o~ the like through the annular
opening 36 to the bearing 30. Thus, the bearing 30 is
substantially protected from the effects of the environ-
ment of the work vehicle 21. Said sealing surfaces
42,44 remain seated on the surfaces 32,34 of the frame
portion 20 and the second end portion 54 of the ley 40
resists deflection from forces exerted on the seal 16
by dirt or the li~e owing to the substantially linear
configuration of the first side 46 of the leg 40 and
its orientation relative to the frame portion 20.
After a period of use of the steering of the
vehicle, it may be desirable to relubricate said bear-
ing 30. The bearing 30 is commonly overfilled to
permit flushiny of the old lubricant from the bearing
30. As the lubricant passes through the bearing 30, it
will urge initially against the first side 46 of the
leg 40 and exert a force on said first side 46. Where
the force is sufficient, the second end portion 54 of
the leg 40 will deflect about the point of intersection
of the first side 46 of the leg 40 and the body 38
owing to the curvilinear configuration of the second
--ll--
side 48 of the leg 40 and the corresponding reduction
in cross-sectional area. Deflection of the second end
portion 54 removes the sealing surfaces 42,44 from
contact with the frame portion 20. The lubricant then
flows from the first channel 90 through the annular
chamber 88 and out the second channel 92. This action
is represented by flow lines 94 in FIG. 1.
Force is also exerted on the third side 50 of
the leg 40 during overfill. This tends to promote
relief or escape of the lubrlcant from the bearing 30.
Where the first and second seallng surfaces 32,34 urge
against the frame portion 20, the relief of saicl
lubricant tends to slow owing to the greater force
required to overcome, for example, the spring 65 or
preload o the leg 40. Following overfill some lubri-
cant will be trapped in the annular chamber 88 and
will act as an additional barrier to foreign matter.
It should be understood that a force exerted on only
the third side 50 of the leg 40 will also deflect the
seal 16.
The first and second sealing areas 42,44
preferably are represented by points of contact such as
are formed by the intersections of the first and third
sides 46,50 and second and third sides 48,50 of the
legs 40, respectively, to reduce friction between the
seal 16 and frame portion 20. The first sealing area
42 will, however, tend to wear a groove into the first
surface 32 during operation of the vehicle steering.
The wearing action on the first sealing area 42 results
in movement of the second sealing surface 34 toward the
first surface 32, but does not interfere substantially
with the performance of the seal 16.
The preferred orientation and configuration
of the seal 16 is shown in the drawings The third
side 50 intersects the first surface 32 at the angle
A5 which is about 45. The first side 46 and linear
-12-
portion 64 of the second side 48 intersect the first
and second surfaces 32,34, respectively, at angles
A6,A7 of about 60, It will be evident from a study of
the drawings that other orientations or configura-tions
of the seal 16 will to sorne degree lessen or increase
the effect of the deflection and sealing capabilities
of the seal 16. For example, a greater angle A5 tends
to reduce the capabilities of seal 16 to relieve the
lubricant flowing through -the bearlng 30 owing to a
reduction in the size of the relief pathway available
to said lubricant.
Other aspects, objects and advantages will
become apparent from a study of -the specification,
drawings and appended claims.
