NZ248317A - Method for forming seal for universal joint: ring seal cut to correct size - Google Patents

Description

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Patents Form No. 5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION VARIABLE SIZE SEAL FOR UNIVERSAL JOINTS WE, THE ZELLER CORPORATION, a corporation in the State of Ohio, U.S.A. of Fort Wayne Road, Defiance, Ohio 43512-0278, U.S.A. hereby declare the invention, for which We pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: -3 AUG 1993 % r. 2^8377 This invention relates to variable size seals for universal joints.

A universal joint seal in accordance with the invention may be generally of the type shown in Mazziotti U.S. Patent No. 4,530,675, issued July 23, 1985. A universal joint of the Cardan type includes two yokes, each having two arms. A universal joint cross with four trunnions are rotatably received in bearing cups which are held in the yoke arms. A sealing ring is located between the base of each trunnion and an open end of the cup in which it is received. Each of the cups has an integral shoulder and a recess at the open end with the sealing ring held between the recess and the base of the trunnion at the body of the cross. The sealing ring has thin lips engaging the trunnion base and a side wall of the cup recess, as well as additional thin lips engaging a shoulder of the body of the trunnion and the internal shoulder of the cup.

Sealing rings for higher production universal joints in which the trunnions are usually less than one inch in diameter are commonly made in multiple cavity molds. However, larger universal joints, and those having trunnions with odd diameters, are made in limited quantities. The high costs of such molds are not warranted for such limited production.

In accordance with the invention, a sealing ring having a cross section generally as described above is made in a curved form having a diameter in excess of the diameter of the trunnions 248317 of some of the larger universal joints to be produced. A segment is then removed from the sealing ring and the cut ends are placed in contact when the sealing ring is assembled with a cup and a cross. The ends of the sealing ring are preferably slit at an angle to provide better contact when assembled. Lubricant can escape between the cut ends when under sufficient pressure in the cup. This eliminates the need for a groove to be molded into the seal for this purpose. For universal joints in which a seal is of a diameter larger than the sealing ring, a segment can again be removed and then a longer segment added between the cut ends to increase the diameter f6r the larger universal joints.

A universal joint seal for the limited production universal joints can also be extruded in a spiral, curved form. The spiral seal can then be cut to the proper length to fit the particular universal joint being produced.

It is, therefore, an object of the invention to provide a universal joint seal which can be used with universal joints having trunnions of various diameters, or to at least provide the public with a useful choice.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a view in elevation of a universal joint cross and bearing cups assembled therewith, with one bearing cup and seal shown in cross section; 2 4 8 3 1 7 Fig. 2 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 retationship; Fig. 3 is a further enlarged, fragmentary view in transverse cross section of the universal joint seal of Fig. 2; Fig. 4 is a top view of a universal joint seal in accordance with the invention; Fig, 5 is a view similar to Fig. 4 with a segment of the seal removed and the cut ends joined to form a seal of smaller diameter; Fig. 6 is a view similar to Fig. 5 but with a larger segment of a seal replacing the segment of the seal shown in Fig. 4 to produce a seal of larger diameter; Fig. 7 is a schematic view of an extruder for producing another universal joint seal; and Fig. 8 is a somewhat schematic view in perspective of a universal joint seal of spiral form produced with the extruder of Fig. 7.

Referring to Figs. 1 and 2, a universal joint cross 20 includes a cross body 22 with shoulders 24 from which extend trunnions 26. The body 22 and the trunnions 26 are provided with lubrication passages 28 which communicate with a supply passage 30 and a lubricant fitting 32. The passages 28 direct lubricant to the ends of the trunnions 26 which have cross passages 34 to supply the lubricant to the needle bearings 36 located between bearing cups 38 and the trunnions 26. With this arrangement, the needle bearings 36 can be lubricated 24 f: * { ? periodically through the fitting 32 to minimize the possibility of the bearings drying out and the universal joint freezing. Permanent lubrication can also be achieved by using lubricant reservoirs in the ends of the trunnions without the passages 28 and 30 and the lubricant fitting 32.

The universal joint cross can also be of the type shown in US Patent No. 5,342,240.

This joint employs two rows of needle or roller bearings and a washer at the outer ends of the bearings.

Each of the bearing cups 38 has an open end 40 to receive the trunnion 26 with the cup having a first cylindrical internal portion 42 of one diameter adjacent the open end of the cup and a second cylindrical internal portion 44 of smaller diameter away from the open end. An internal shoulder 16 is formed between the two portions 42 and 44 and faces the open end of the cup.

A universal joint seal 48 in accordance with the invention is provided to effectively seal off the annular space between the bearing cup and the cross. This seal 48 comprises a resilient sealing ring or member 50 made entirely of resilient material, preferably synthetic rubber with a typical hardness of eighty to ninety-five durometers. The sealing member 50 has inwardly-extending circular lips 52 which engage the trunnion 26 near the cross body 22. The circular lips 52 are narrow and engage the trunnion along narrow, annular areas to provide three seals, in this instance, between the sealing member 50 and the cross 20. 24 8 3 1 7 The sealing member 50 also has three outwardly-extending circular lips 54, in this instance, which engage the surface of the first cylindrical internal portion 42 of the bearing cup 38. These engage the surface along narrow, annular areas to provide three seals between the sealing member 50 and the cup 38.

The sealing member 50 further has upwardly-extending narrow circular lips 56 between the inner lips 52 and the outer lips 54 which engage the shoulder 24 of the cross body 22 to engage the shoulder 24 along narrow, annular areas to provide additional seals between the sealing member 50 and the cross 20. The sealing member 50 also has a downwardly-extending lips between the inner and outer lips 5 2 and 54. The lip 58 engages the internal shoulder 46 along a narrow, annular area to provide a fourth seal between the sealing member 50 and the cup 38. The multiple lips, through their engagement with the cross body and cup, also retain the seal 48 in its proper sealing position. The thin lips of the seal also accommodate dimensional variations in the cup and trunnion.

The lips 52 and 56 primarily inhibit ingress of water and other contaminants into the cup 38 while the lips 54 and 58 primarily retain lubricant in the bearings and can relieve lubricant pressure in the cup 38 when lubricant is again supplied to the fitting 32. In addition, the sealing member 50 also has a thicker, downwardly-extending lip 60 which engages the upper ends of the needle bearings 36 to retain them in place when the cup 38 is separated from the trunnion 26. The lip 60 also tends 2 4 8 3 1 7 to direct lubricant out of the cup between the sealing member 50 and the cylindrical portion 42 of the cup when lubricant is supplied.

The sealing ring or member 50 is shown in a top view in Fig. 4. The ring can be molded in a single cavity mold.which is much less expensive than the multiple cavity molds used for higher production universal joints. The ring 50 preferably is molded in a diameter between the largest and smallest seals to be made. For example, the sealing ring 50 can be made in a one and one-half inch diameter to fit cross trunnions from one inch to two inches in diameter. The sealing rings shown in Figs. 4-6 are of double scale.

The ring 50 is Fig. 4 can be used with a cross having approximately one and one-half inch diameter trunnions without modification. A sealing ring indicated at 62 in Fig. 5 is a modification of the sealing ring 50 to fit a cross having approximately one inch diameter trunnions. In this instance, the sealing ring 50 of Fig. 4 is diagonally slit or cut at 64 and 66 with a segment 68 therebetween then being removed. The slit ends are then placec in contact at 7 0 in Fig. S to produce a ring of the desired diameter.

A sealing ring 72 of a larger diameter to fit a trunnion of approximately two inch diameter is shown in Fig. 6. In this instance, the segment 68 of Fig. 4 is again removed and then replaced with a longer segment 74 between the cut ends 64 and 66 of the ring 50. For trunnions of odd sizes between one inch and two inches in diameter, the segment 68 or 74 can be modified in length accordingly. 248317 The slit ends of the ring preferably are cut at a forty-five degree angle to the radius. These are placed in contact during assembly of the ring and the bearing cup to provide an effective seal for lubricant. At the same time, with sufficient pressure of the lubricant in the bearing cup, excess lubricant can escape between the cut ends. This eliminates the need for a groove to be molded into the ring which is otherwise often done to enable lubricant to escape during the lubricant of the universal joint.

If necessary, the sealing ring SO can be molded in other, larger diameters, for still larger universal joints. There is a limit to the diameter that the ring can accommodate since if the ring is made in an excessively small diameter, the inner lips 52 can tend to wave or buckle. At the same time, if the sealing ring is expanded excessively, with longer segments employed, the outer lips 54 can tend or wave or buckle.

A sealing member 76 is shown in a spiral in Fig. 8. This sealing member can be cut to a length to accommodate the circumference of a particular universal joint with which it is to be used.

The sealing member 76 can be made with a commercially-available extruder indicated at 78 in Fig. 7. The extruder 78 includes a barrel 80 having an auger therein which forces 24 8 3 1 a rubber or thermoplastic material supplied to a hopper 82 through a suitable nozzle 84 at the end of the barrel. The nozzle 84 can be designed to produce the sealing member 76 in any particular size to accommodate a range of sizes of universal joints.

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 10 without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

Claims (10)

WHAT WE CLAIM IS 248317

1. A method of making a universal joint seal for use between a trunnion and a cup, with the cup having an open end and a closed end, said method comprising molding an annular member of resilient material having a circumference exceeding a circumference of the open end of the cup, said member having a cross-sectional shape equal to the cross-sectional shape of the universal joint seal, cutting a segment from said member so that the circumference of said member is substantially equal to the circumference of the cup, inserting the cut member into the open end of the universal joint cup, and assembling the cup and the trunnion.

2. A method of making a universal joint seal for use between a trunnion and a cup, with the cup having an open end and a closed end, said method comprising molding an annular member of resilient material having a circumference less than a circumference of the open end of the cup, said member having a cross-sectional shape equal to the cross-sectional shape of the universal joint seal, cutting a segment from said member, replacing the cut segment with a longer segment, inserting the cut member and longer segment into the open end of the universal joint cup, and assembling the cup and the trunnion.

3. A method according to claims 1,-aftd- 2 wherein the member is cut at an angle to the radius of the member.

4. A universal joint comprising a cross having four trunnions and annular shoulders around said trunnions, a bearing cup for each of said trunnions, said bearing cup having an open end which receives the trunnion, said bearing cup having a first interior portion of circular cross section of one diameter adjacent the open end, said cup having a second, cylindrical interior portion of a smaller diameter 11 248317 away from said open end, with an internal shoulder formed between said portions, a universal joint seal for each of said bearing cups, said seal comprising a resilient sealing member having a first lip engaging the associated trunnion shoulder and at least two lips engaging the associated trunnion along narrow, annular areas, said sealing member having a second lip extending in a direction generally opposite to said first lip and engaging the shoulder of the associated bearing cup along a narrow, annular area, said sealing member having at least two additional lips engaging said first interior portion of the associated cup along narrow, annular areas, said resilient sealing member having two diagonal ends cut on a line diagonal to an axis of the member and which are in contact when the sealing member is between said trunnions and said cup.

5. The universal joint according to claim X^wherein said sealing member has two additional diagonal ends cut on a line diagonal to an axis of the member and which are in contact when the sealing member is between said member and said cup.

6. A method as claimed in claim 1 substantially as herein described with reference to the accompanying drawings.

7. A method as claimed in claim 2 substantially as herein described with reference to the accompanying drawings.

8. A universal joint seal formed by the method of any one of claims I to j£. 1 —3, c "3.

9. A universal joint seal substantially as herein described with reference to the accompanying drawings.

10. A universal joint incorporating a universal joint seal according to claim 8 or claim 9.