Reversible universal joint seal

A universal joint seal is symmetrical about a transverse plane taken centrally therethrough. In this manner, the seal can be properly and correctly inserted into a bearing cup from either end. This eliminates the requirement for sorting for orientation of the seals after they are made. Either a mechanical sorter is eliminated or an operator for sorting the seals is eliminated.

This invention relates to a reversible seal designed particularly for 
universal joints having trunnions and bearing cups. 
A number of seals for use between cross trunnions and bearing cups of 
universal joints are known in the art. More specifically, internal 
universal joint seals having multiple lips to provide more effective seals 
have been disclosed before in my U.S. Pat. Nos. 4,515,574, issued May 7, 
1985; 4,530,675, issued Jul. 23, 1985; and 4,861,315, issued Aug. 29, 
1989. 
The seal in accordance with the invention is particularly designed for 
small universal joints but can also be used for larger ones. The new 
reversible seal is contained between a trunnion of the universal joint 
cross body and an inner cylindrical surface of the bearing cup. It is also 
contained between the tops of needle bearings in the cup or a shoulder in 
the cup and also a shoulder on the body of the cross. The seal has first 
lips which engage the trunnion of the bearing cross adjacent the shoulder 
and lips which are staggered with respect to the first ones and which 
engage the cylindrical surface of the bearing cup near the open end 
thereof. The seal also has a downwardly-extending lip which engages the 
tops of the needle bearings and an upwardly-extending lip which engages 
the shoulder of the cross body. The open end of the bearing cup extends 
upwardly near the shoulder of the cross body to help provide a contained 
space for the seal. 
Heretofore, when the seals were made, they had to be sorted either 
mechanically or by an operator, so as to be properly positioned when they 
are assembled with the bearing cups. 
The reversible seal in accordance with the invention can be inserted in the 
bearing cups from either end of the seal and, therefore, the sorting 
operation is completely eliminated. Further, the seal cannot be 
incorrectly assembled with the cup. 
It is, therefore, a principal object of the invention to provide a 
reversible seal for a universal joint, to be located between the bearing 
cup and the cross trunnion, which can be inserted in the cup from either 
end of the seal.

Referring to FIG. 1, a universal joint embodying the invention is indicated 
at 10 and connects shafts 12 and 14. The universal joint and shafts can be 
used in many applications, cars and trucks, for example. 
The universal joint 10 includes two yokes 16 and 18 disposed at 
mutually-perpendicular angles with bearing cups 20 held in arms of the 
yokes by suitable means, such as a retaining ring 22 which is held in a 
groove 24 in the yoke arm, as is known in the art. 
Referring to FIG. 2, a cross 26 of the universal joint includes a body 28 
having an annular shoulder 30 from which extends a trunnion 32. In this 
instance, the trunnion 32 also has a narrow annular offset 34 spaced below 
the shoulder 30. Needle bearings 36 can be located between the trunnion 32 
and the cup 20. If desired, the cross 26 can have lubricating provisions 
for the needle bearings, as is known in the art. 
The bearing cup 20 has a bottom wall 38 and a thin cylindrical side wall 40 
which extends upwardly near the cross body shoulder 30 when the trunnion 
32 is fully inserted in the cup 20. 
A resilient annular seal 42 is accordance with the invention is provided to 
effectively seal off the annualr space between the bearing cup 20 and the 
trunnion 32. The seal 42 is contained between the trunnion 32 and an inner 
cylindrical surface 44 of the cup 20 and between the annular shoulder 30 
and the upper ends of the needle bearings 36. The seal 42 comprises a 
resilient sealing member 46 preferably made of rubber with a typical 
hardness of eighty to ninety-five durometers. It does not require metal 
inserts or metal backing as some seals heretofore employed, such seals 
being relatively expensive. 
Referring to FIG. 2, the sealing member 46 has an upper, inwardly-extending 
circular lip 48 which engages the trunnion 32 near the cross body 28. 
Similarly, the sealing member 46 has a lower, inwardly-extending circular 
lip 50 which engages the upper ends of the needle bearings 36. In between 
the ends of the sealing member 46 are two circular lips 52 and 54 which 
engage the trunnion along rather narrow, annular areas to provide two 
seals primarily intended to keep out contaminants and water. Further, 
between the ends of the sealing member 46 are three outwardly-extending 
circular lips 56, 58, and 60 which engage the inner cylindrical surface 44 
of the bearing cup 20 along rather narrow, annular areas. These are also 
intended to keep out contaminants and water. The lips 50 and 60 are also 
intended to retain lubricant around the, needle bearings in the cups. 
The lips 52 and 54 of the sealing member 46 are symmetrically staggered 
with respect to the lips 56, 58, and 60 to provide a better fit for the 
seal 42 between the trunnion and the cup. The first lips are directly 
opposite valleys between the second lips and the second lips are directly 
opposite valleys between the first lips. 
The seal 42 is symmetrical about a central plane taken centrally through 
the seal. Specifically, the seal 42 is symmetrical with respect to a plane 
taken through the central outer lips 58. This enables the seal 42 to be 
inserted from either end into the cup 20 without requiring that it be 
sorted, either mechanically or by an operator, prior to assembly. Further, 
the seal cannot be incorrectly assembled with the cup. 
Referring to FIG. 3, a modified cross 62 of a universal joint includes a 
body 64 having an annular, square shoulder 66 from which extends a 
trunnion 68 which is straight, without an offset, in this instance. A 
modified bearing cup 70 has a cylindrical side wall 72 which extends 
upwardly near the cross body. The cup 70 has an inwardly offset lip 74 
extending upwardly further toward the cross 62. 
In this instance, two, rows 76 and 78 of needle bearings are located 
between the cup and trunnion and have a washer 80 therebetween and an 
upper washer 82 above the upper row 78. 
The same seal 42 is employed as in FIG. 2. However, the end lip 48 bears 
against a plastic shield 84 and specifically against a longer leg 86 
thereof located between the seal and the shoulder 66 of the cross 62. The 
shield 84 also has a downwardly-extending lip 88 which protects against 
contaminants and water. The lip 88 of the shield 84 is located adjacent 
the offset lip 74 of the bearing cup 70 so as not to project beyond the 
outer surface of the bearing cup 70, particularly for purposes of 
assembly. The end lip 50 of the seal 42 bears against the upper washer 82 
rather than against the ends of the needle bearings. As before, the seal 
42 is symmetrical about a central plane so as to be reversible and 
inserted in the cup from either end of the sea. 
Referring to FIG. 4, a modified cross 90 of a universal joint includes a 
body 92 having an annular, square shoulder 94 from which extends a 
trunnion 96. The trunnion 96 has a straight portion 98 and an upward, 
outwardly-flaring portion 100 near the shoulder 94. A modified bearing cup 
102 has a cylindrical side wall 104 extending upwardly toward the 
universal joint cross 90 with an offset 106 therein. An upper end of the 
bearing cup 102 has on its inner surface, an outwardly-flaring portion 
108. A single row 110 of needle bearings is located between the trunnion 
96 and the bearing cup 102. 
The same seal 42 is employed as in FIGS. 2 and 3. The end lip 48 bears 
against the shoulder 94 and the end lip 50 bears against the upper ends of 
the needle bearings 110. The inwardly-extending lip 52 bears against the 
flared portion 100 of the trunnion 96 and the outwardly-extending lips 58 
and 60 bear against the flared portion 108 of the cup 102. In this 
instance, the lips 54 and 56 are spaced from the trunnion 96 and the cup 
102, respectively. 
Again, the seal 42 is symmetrical with respect to a central plane so as to 
be inserted from either end into the cup 102 without requiring that it be 
sorted and also assuring that it will not be assembled incorrectly. 
Referring to FIG. 5, a slightly modified cross 112 includes a body 114 
having an annular, square shoulder 116 from which extends a trunnion 118 
having a straight portion 120 and an offset 122. An upper cylindrical 
portion 124 is located between the offset 122 and the shoulder 116. A 
slightly modified bearing cup 126 has a cylindrical side wall 128 which 
extends upwardly near the cross body. The bearing cup 126 also has an 
inwardly offset lip 130 extending upwardly further toward the cross body 
114. In this instance, the bearing cup 126 also has an inner shoulder 132 
facing toward the open end of the cup. 
A resilient annular seal 134, in accordance with the invention, is provided 
to effectively seal off the annular space between the bearing cup and the 
trunnion. The seal 134 is contained between the cylindrical portion 124 of 
the trunnion 118 and an inner cylindrical surface 136 of the cup 126. It 
is also contained between the inner shoulder 132 of the bearing cup 126 
and the plastic shield 84 which is shown and discussed in FIG. 3. 
The seal 134 comprises a resilient sealing member 138 having an upper, 
inwardly-extending circular lip 140 which engages the cylindrical portion 
124 of the trunnion and also the inner end of the plastic shield 84. 
Similarly, the sealing member 138 has a lower, inwardly-extending circular 
lip 142 which engages the washer 82 on top of the upper row of needle 
bearings 78 which are also shown in FIG. 3. Between the ends of the 
sealing member 138 is a central lip 144 which engages the portion 124 of 
the trunnion along a rather narrow, annular area. A sealing member 138 
also includes two outwardly-extending lips 146 and 148 which engage the 
inner cylindrical surface 136 of the cup 126 along rather narrow, annular 
areas. In addition, the sealing member 138 has a thin lip 150 at its upper 
end which engages the plastic shield 84 and a thin lip 152 at its lower 
end which engages the inner shoulder 132 of the cup 126. 
The seal 134 is intended to keep out contaminants and water and also to 
retain lubricant around the needle bearings and the cup. 
The lips 146 and 148 are staggered with respect to the lip 138 to provide a 
better fit for the seal. The lip 144 is directly opposite a valley between 
the lips 146 and 148. 
While the seal 134 is a substantially different shape than the seal 42, 
again it is symmetrical with respect to a central plane extending through 
the inner lip 144 so that the seal does not need to be sorted and cannot 
be inserted incorrectly. 
Referring to FIG. 6, a modified cross 154 of a universal joint includes a 
body 156 having an annular, square shoulder 158 and a straight portion 
160. A cylindrical portion 162 is located between the straight portion 160 
and the shoulder 158 and a thinner, larger diameter cylindrical portion 
164 is located between the shoulder 158 and the body 156 of the cross. A 
modified bearing cup 166 has a cylindrical outer side wall 168 and an 
extending lip 170 which extends upwardly near the thinner cylindrical 
portion 164 of the cross. The bearing cup 166 also has an inner shoulder 
172 and an upper, inwardly-facing cylindrical surface 174 thereabove. 
A modified resilient seal 176 comprises a resilient sealing member 178 
having an inwardly- and upwardly-extending lip 180 at its upper end and a 
downwardly-extending inner lip 182 at its lower end. The upper lip engages 
the cross at the juncture of the cylindrical portion 162 and the shoulder 
158 while the lower lip 182 contacts the washer 80 on top of the needle 
bearings 78 as shown in FIGS. 4 and 5. The resilient sealing member 178 
also has an outwardly- and upwardly-extending lip 184 at its upper end 
which engages the shoulder 158 and the inner cylindrical surface 174 of 
the bearing cup 166. 
The sealing member 178 also has a lip 186 at its lower end which extends 
downwardly and outwardly and engages the bearing up at the juncture of the 
cylindrical surface 174 and the inner shoulder 172. 
Between the ends of the resilient sealing member 178 are two 
inwardly-extending lips 188 and 190 which engage the cylindrical portion 
162 of the cross. Between the ends of the member also is an 
outwardly-extending lip 192 which is staggered with respect to the lips 
188 and 190, being directly across from a valley between those lips. The 
lip 192 engages the cylindrical portion 174 of the bearing cup 166. The 
seal 176 along with the close fit between the cup lip 170 and the thin 
cylindrical portion 164 of the cross keep out contaminants and water and 
retain lubricant in the bearing cup around the bearings. Because of the 
close fit between the cup lip 170 and the cylindrical portion 164 of the 
cross, it may be necessary to provide a lubricating system as shown in 
Mazziotti and Sowers U.S. patent application Ser. No. 08/391,594, filed 
Feb. 21, 1995, to provide lubricant for the bearings. 
The seal 176 is symmetrical with respect to a central plane extending 
through the outwardly-extending lip 192 so that it can be inserted in the 
bearing cup from either end of the seal. Again, this eliminates sorting 
and prevents incorrect assembly. 
Referring to FIG. 7, a modified cross 194 includes a body 196 having an 
annular, slanted shoulder 198 from which extends a trunnion 200. A bearing 
cup 202 is similar to the bearing cup 20 and has a cylindrical side wall 
204 extending upwardly near the cross body 196. 
Two rows 206 and 208 of needle bearings are located between the trunnion 
200 and the cup wall 204. The two rows are separated by a washer 210, with 
a washer 212 located on top of the row 208 of bearings. 
A reversible, resilient seal 214, in accordance with the invention, is 
provided to effectively seal off the annular space between the bearing cup 
and the trunnion. The seal is contained between the trunnion 200 and the 
cylindrical wall 206 of the cup 202. It is also contained between the 
annular, slanted shoulder 198 of the cross 194 and the washer 212. 
The seal 214 comprises a resilient sealing member 216 having 
inwardly-extending circular lips 218 and 220 which engage the trunnion 
200. Similarly, the sealing member 216 has three outwardly-extending lips 
222, 224, and 226 which engage the cylindrical wall 204 of the cup 202. 
The resilient sealing member 216 also has an upwardly-extending, slanted 
lip 228 at its upper end which engages the annular, slanted shoulder 198 
and a lower slanted lip 230. 
Further, the slanted lips 228 and 230 are identical so that the seal can be 
inserted from either end. Otherwise, the lower lip 230 could be square in 
so far as its functionality is concerned, namely to press downwardly on 
the washers and bearings. Again, the seal 214 is symmetrical about a 
central plane to eliminate sorting and to eliminate incorrect assembly. 
As will be seen from above, the sealing member according to the invention, 
while of different shapes, has at least one upwardly- and 
inwardly-extending lip at its upper end and at least one downwardly- and 
inwardly-extending lip at its lower end. Further, the sealing member has 
at least one inwardly-extending lip engaging the trunnion of the cross and 
at least one outwardly-extending lip engaging an inner surface of the 
bearing cup. In all instances, the sealing members are symmetrical with 
respect to a central plane so that they can be inserted in the cups from 
either of their ends. 
All of the seals can be used with either single or double rows of needle 
bearings with flat or rounded tops. They can also be used with washers 
above the top ends of the needle bearings and with or without washers 
between two rows of needle bearings when two rows are employed. 
All of the seals can be made of similar material as discussed in connection 
with the seal 42 of FIG. 2. 
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 within the spirit and the tenor of the 
accompanying claims.