Note: Descriptions are shown in the official language in which they were submitted.
This inven-tion relates to an internal universal joint
seal which is more e-ffective to contain lubricant and to prevent
the ingress of water and contaminants.
Seals between crosses and bearing cups of univcrsal ~oints
must meet difficult conditions. Since there is relative ro-
tational movement between the cross trunninns and the bearing
cups, the seals have to provide the sealing function while
encountering movement between the seals a~d the sealing surfaces
of the cross and/or cups. The seals must also contain the
lubricant in the cups between the innver surface thereof and the
trunnions even during high rotational movement of the universal
joint and when subject to torque during operation of the drive
train in which the universal joint is located. At the same time,
poweve~, with universal joints having lubricant fittings so that
the bearings can be periodically lubricated, the seals must
enable sorne o~ the old lubricant to be flushed from the bearings
during lubrication. In addition, the universal joint seals must
be effective in preventing the ingress of water and contaminants
w~ich can quickly cause bearing failure even in small amounts.
Preferably, the seals also should not project beyond the periph-
eries of the bearing cups so as not to inhibit assembling of the
cross and the cups along with the yokes of the universal joint.
A number of seals for use between crosses and bearing cups
of universal joints are known in the art. One common seal
includes a resilient sealing member having one portion contoured
to the shape of the cross at the ~uncture of the body and
trunnion and another portio~ contoured to the shape of the
sur~ace near the open end of the bearing cup so as to provide
wide areas of contact between the sealing member and both the
cross and cup. Such seals, however, are sometimes less than
effective, particularly when the surfaces of the cross and cup
--2
~`.
fi g
which are engaged by the sealing member are relatively rough,
having circular irregularities therein. Abrasion and wear of
the sealing member also can be a problem with this type of seal
and universal joint surfaces. Other universal joint seals are
shown in the ~ollowing U.S. patents:2,773,367, issued to W. W.
Slaght on December 11, 1956; 3,138,9~2 issued to J. A. Kayser
on June 30, 1964; 3,377,820 issued to W. J. Smith, Jr., on
~pril 16, 1968; 3,581,524 issued to A. Pitner on June 1, 1971;
3,788,100 issued to A. Pitner on January 29, 1974; and 3,006,746
issued to C. W. Haines on September 23, 1975.
~ he present invention provides an improved internal univer-
sal joint seal having multiple lips to provide more ef~ective
seals. The cross of the universal joint includes a body and
four trunnions extending therei'rom at mutually perpendicular
angles, with the cross often having an annular shoulder at the
juncture o~ the body and each trunnion. Each bearing cup of the
universal ~oint with which the internal seal is used has an open
end which receives one of the trunnions. The cup has a ~irst
cylindrical interior portion of one diameter adjacent the open
end and a second cylindrical interior portion oi a smaller
diameter away from the open end, forming an annular internal
shoulder between the portions and facing toward the open end.
The internal universal joint seal according to the in-
vention includes a resilient seaLin~ member having multiple lips
engaging the first Cylindrical interior portion of the cup and
also having multiple lips engaging the surface of the trunnion
adjacent the cross body. The sealing member has an additional
lip between the two sets of multiple lips engaging the internal
shoulder of the cup and a second additional lip or ridge
between the two sets of multiple lips engaging the body of the
cross. Where the cross body has a relatively smooth sh~ulder
adjacent the -trunnion, the second add:itional lip forms an addi-
.
--3--
tlonal seal. Where there is no annular shoulder, the second lipor ridge engages the body directly to retain the resilient
sealing member in place between the cup and the trunnion, along
with the additional lip which engages the internal shoulder of
the cup, The multiple lips engaging the trunnion are effective
to prevent the ingress of water and contaminants and the outer
set of lips engaging the first cylindrical interior portion of
the cup also enable the egress of lubricant from the cup during
lubrication, This enables dirty lubricant to be flushed complete-
lQ ly from the bearing cup if desired,
In one form, the resi~ient sealing member has a larger lipextending downwardly and inwardly over upper ends of needle bear-
ings to help retain them in place when the cup and the trunnion
are separated,
The sealing lips of the resilient member have narrow
squared or rounded ends which provide narrow lines of contact
with the cross and the bearing cup. Thus, the sealin~ lip ends
providing substantially line contact with the cross and the cup
when the lips are deformed when assembled with the cross and the
cup, This provides good sealing engagement with the surfaces,
particularly when they have circular surface irregularities
therein, In contrast, previous seals were designed to have
contours fitting with associated contours of the cross and cup
to provide broad engagement therebetween, Such seals do not
have as effective sealing engagement with ~he surfaces when
such surfaces tended to be rough and have irregularities therein
and the seals wear rapidly.
The relatively narrow lips of the resilient sealing member
also can be deormed substantially when the cross and the cup are
3n assembled so that the seal can accommodate wider tolerance ranges
in the universal joint, Also, the multiple seals form
annular cavities therebetween which can trap lubricant tendin~
to egress and water an~ contaminants tending to ingress. In such
instances, the trapped lubricant, in turn, tends to be e~fective
in inhi~iting the ingress of contaminan-ts and water.
The sealing member also is designed to fit within the
bearing cup in a manner such that the seal does not project beyond
outer surfaces of the bearing cup. This facilitates assembly o~
the bearing cup with the trunnion by inserting the bearing cup
-through an opening in the universal joint yoke. The internal
seal also is protected from possible damage by being substant-
ially located within the cup.
The seal is effective to contain the lubricant and to
prevent the ingress of water and contaminants even during
relative rotational movement of the trunnion and the bearing cup
and also during high rotational speeds of the universal joint.
At the same time, however, the seal is suf~iciently soft that
lubricant supplied through the cross to the needle bearings in
the bearing cup can flush out the old lubricant between the seal
and the bearing cup.
It is, therefore, a principal object of-the inv~ntion to
provide an internal universal joint seal for a universal joint
having improved sealing properties with a cross and cup o~ the
joint.
Another object of the invention is to provide an internal
joint seal capable o~ accommodating greater tolerance ranges or
dimensional variations in the cross and cups of the universal
joint.
A further object of the invention is to provide an internal
universal ~oint seal having multiple lips engaged with the cross
and multiple lips engaged with the cup to provide effective
-lubricant and contaminant seals.
--5--
Yet another ob~ect of the invention is to provide an
internal universal joint seal capable of achieving grea~er
sealing effectiveness with sur~aces of the cross and cup o~ the
~Iniversal ~oint when they have circular surface irregularities
thereon.
Still another object of the invention is to provide an
internal universal joint seal located substantially wholly within
an open end portion of the bearing cup which protects the seal
from damage.
Many other objects and advantages of the invention will be
apparent from the ~ollowing detailed description of preferred
embodiments thereof, rei'erence being made to -the accompanying
drawings, in which;
Fig. 1 is a view in elevation of an assembled universal
joint connecting two shafts and embodying the invention;
Fig. 2 is a view in elevation of the universal joint and
bearing cups assembled therewith, with one bearing cup and seal
shown in section;
Fig. 3 is a greatly enlarged, fragmentary view in cross
section of a trunnion of a universal joint cross, a bearing cup,
and a universal Joint seal according to the invention, in
assembled relationship;
Fig. 4 is a further enlarged, fxagmentary view in trans~
verse cross section of the universal joint seal of Fig. 3;
Fig. 5 is a fragmentary view in cross section of a trunnion
of a universal joint cross, a bearing cup, and a modified
universal joint seal according to the invention, in assembled
relationship, and on the same scal~ as Fig. 3;
Fig. 6 is a fragmentary view in transverse cross section
of the universal joint seal of Fig. 5, and on the same scale as
Fig. 4; and
--6--
~t;4~
Fig. 7 is a ~ragmentary view in cross section o~ a trunnion
of a universal joint cross, a bearin~ cup, and a further modified
universal joint seal according to the invention, in assembled
relationship, and on the same scale as Fig. 5.
~ eferring to ~ig. l, a universal joint embodying the
invention is indicated at lO and connects driving and driven
sha~ts 12 and l~ in the conventional manner. The joint 10 in-
cludes two yokes 16 and 18 disposed at mutually perpendicular
angles with bearing cups 20 held in arms of the yokes by suitable
means, such a.s retaining rings 22 (Figs. l and 2) which are held
in grooves 24 (Fig. 1) in the arms of the yokes, as is known in
the art.
Referring to Figs. 2 and 3, a cross ~6 of the universal
joint includes a body 28 with shoulders 30 from which extend
trunnions 32. The body 28 and the trunnions 32 are provided with
lubrication passages 34 which communicate with a supply passage
36 and a lubricant fitting 38. The passage 34 directs lubricant
to the end of the trunnion 32 which has a cross passage 40 to
supply~tpe~ubric~nt toineedlel~bearing~ g2~:~oc~ed;:betw~encthe
bearing cup 20 and the trunnion 32. With this arrangement, the
needle bearings 42 can be lubricated periodically through the
fitting 38 to minimize the possibility of the bearings drying
out and the universal joint freezing.
~ ach of the bearing cups 20 has an open end to receive the
trunnion 32 with the cup having a first cylindrical internal
por~ion 44 of one diameter adjacent the open end and a second
cylindrical internal portion 46 of smaller diameter away from
the open end. An internal annular shoulder 48 is formed between
the two portions 44 and 46 and faces the open end,
~;~6~
Resilient sealing members heretofore formed between the
cups and crosses of universal joints commonly have been designed
with contours conforming to the contours of the cross at the
juncture of the body and trunnions and also with the contours
of the open ends of the bearing cups. The purpose was to provide
a large contact area which might be expec~ed to provide better
seals. ~Iowever, the surfaces at the junctures of the cross body
and trunnions and the contoured open ends of the bearing cups
have not always been as smooth as o-ther portions of the cross and
cups. Such surfaces commonly have had circular irregularities
which have prevented effective seals with the sealing member, in
some instances ~lso, substantial abrasion has resulted to the
resilient sealing member at times where relative movement occurs
between the cross and/or cup and the sealing member.
A universal joint seal 50 in accordance with the invention
is provided to more effectively seal off the annular space
between the bearing cup and the cross 26. The seal 50 comprises
a resilient sealing member 52 made entirely of resilient material
preferably of synthetic rubber with a typical hardness of 80-95
durometers, and does not require meta~ inserts or me-tal backing
as some seals heretofore employed, such seals being relatively
expensive. The member 52 has at least two inwardly-extending
circular lips 54 and 56 which engage the trunnion 32 near the
cross body 28. The circular lips 54 and 56 are narrow and engage
the trunnion along narrow, annular areas to provide two seals
between the sealing member 52 and the cross 26. The sealing
member 52 also has two outwardly-extending circular lips 58 and
60 which engage the inner surface of the ~irst cylindrical
in~ernal portion 44 of the bearing cup 20. These engage the
surface along narrow, annular areas to provide two seals between
the sealing member 52 and the cup 20.
The sealing member 52 also has an upwardly-extending narrow
circular lip 62 between the inner multiple lips 54 and 56 and
the outer multiple lips 58 and 60. The lip 62 engages the
shoulder 30 o e the cross body 2~, in this instance, along a
narrow, annular area to provide a third seal between the sealing
member 52 and the cross 26. The sealing member 52 also has a
downwardly-extending narrow circular lip 6~ between the inner
multiple lips 54 and 56 and the outer multiple lips 58 and 60.
The lip engages the internal shoulder 48 of the bearing cup
20 along a narrow, annular area to provide a third seal between
the sealing member 52 and the cup 20. The lips 62 and 6~,
through their engagements with the cross body 28 and the shoulder
48, also retain the seal 50 in proper sealing position. The
lips 54-~4 thus provide three narrow sealing areas with the
trunnion 32 and the cross body 28 and also three narrow sealing
areas with the cylindrical portion 44 and the shoulder 48 of
the cup 20. The lips 54, 56, and 62 primarily inhibit ingress
of water and other contaminants into the cup 20 while the lips
58,60, and 64 primarily control the flow of lubricant out of
the cup 20 when lubricant is supplied to the fitting 38.
As shown in Fig. 4, the lips preferably terminate in
narrow edges having sharp or slightly rounded corners. The
narrow edges provide narrow, more concentrated contact between
the sealing member 52 and the cross and cup. When the sealing
members are deformed as the cross and cup are assembled, the
contact between the lips and the cross and cup is even narrower,
being between the corners of the lips and the surfaces they en-
gage. Thus, when the surfaces have circular irregularities
thereon, the narrow contact of the lips and the surface can
provide even greater sealing effectiveness than when the
resilient sealing member engages the entire surface. This is
_9_
particularly true when the resilient sealing member is somewhac
harder7 in the order of 90-95 durometers, than when the sealing
member is softer with a hardness in the order of 80 durometers.
I he annular cavities formed between the lips 54 and 56
and bet~een the lips 58 and 60 trap water and contaminants
tending to ingress into the cup. They also trap lubricant
tending to egress from the cup with the lubricant so trapped
being a further inhibition to the ingress of water and contam-
inants.
A modified seal 66 according to the invention is shown in
Figs. 5 and 6. The seal includes a sealing member 68 having
three inwardly-extending, narrow circular lips 70, 72 and 74.
These engage ~he trunnion 32 adjacent the cross body 28 to pro-
vide three narrow sealing areas between the sealing member and
the cross. The sealing member 68 also has three outwardly-
extending, narrow circular lips 76,78 and 80. These engage
the first cylindrical portion 44 of the cup 20 to provide ~hree
narrow circular sealing areas between the sealing member 68 and
the cup 20.
The sealing member 68 also has an upwardly-extending lip
82 between the inner and outer sets of lips with the lip 82
engaging the cross body 28 and specifically the cross body
shoulder 309 in this instance. The sealing member 68 also has
a downwardly-extending lip 84 between the inner and ~he outer
sets which engages the internal shoulder 48 of the cup 20. Thus9
the lips 82 and 84 retain the seal 66 in proper position as well
as provide additional narrsw sealin~ areas between the sealing
member and the cross body and cup.
The sealing member 68, in this instance, also has a longer,
inwardly and downwardly-extending lip 86 which engages the upper
ends of the needle bearings 42 to re~ain them in place when the
cup 20 is separated from the ~runnion 32. The lip 86 also tends
-10-
~ direct lubricant o~t of the cup between the sealing member 68
and the cylindrical portion 44 when lubrication is supplied.
A further modified seal 88 according to the invention is
shown in Fig. 7, along with a modified cross body 90. The cross
body 90 differs from the body 28 in that it has no shoulder 30
thereon but simply has the trunnion 32 extending directly from
the body. The surface of the body 90 tends to be rougher than
the shoulder ~0, which is machined, while the body 90 as formed
is normally not subsequently smoothed by any machining or grind-
ing operation.
The seal 88 includes a sealing member 92 having threeinwardly-extending, narrow circular lips 94, 96, and 98. These
engage the ~runnion 32 adjacent the cross body 90 to provide
three narrow sealing areas between the sealing member and the
cross. The sealing member 92 also has two outwardly extending,
narrow circular lips 100 and 102. These engage the first cy-
lindrical portion 44 of the cup 20 to provide two narrow circular
sealing areas between the sealing member 92 and the cup 20.
The sealing member 92, in this instance, has a thick
upwardly-extending lip or ridge 104 between the inner and outer
sets of lips with the lip 104 engaging the cross body 90. How-
ever, the thick lip 104 does not provide an effective seal
between the sealing member 92 and cross body because of the
rough surface thereof. Hence, the main function of the lip 104
is to aid in retaining the sealing member 92 in sealing position
while the lips 94, 969 and 98 provide three narrow sealing areas
between the sealing member and the cross body. The sealing
member 92 also has a downwardly-extending lip 106 hetween the
inner and outer sets of lips. The lip 106 engages the internal
shoulder 48 of the cross 20 to provide an additional narrow
sealing area between the sealing member and the cup and at the
same time to coopera~e with the thick lip 104 to aid in retaining
-11 -
the seal 88 in position. The lips 100~ 102, and 106 thus also
provide ~hree narrow sealing areas between the sealing member
and the cup.
From the above, it will be seen tha~ the internal seal
according to the invention provides at least two narrow sealing
areas between the sealing member and the cross and at least two
narrow sealing areas between the sealing member and the cup. A~
the same time, the sealing member has at leas-t one additional
upper lip and at least one additional lower lip which cooperate
with the cross body and with ~he internal shoulder of the cup to
retain the seal in position.
Various modifications of the above-described embodiments
of the invention will be apparent to those skilled in the art,
and it is to be understood that such modifications can be made
without departing from the scope of the invention, if they are
with.in the spirit and the ~enor of the accompanying claims.
