Swivel joint with stepped bearing races

Abstract

A swivel joint comprises a tubular male member having at least first and second outer annular grooves formed on an outer surface, a tubular female member having at least first and second inner annular grooves formed on an inner recess, and a plurality of balls disposed in at least first and second annular races which are formed by the alignment of the first and second outer grooves with the first and second inner grooves when a first end of the male member is received within the recess of the female member. In addition, the radius of the first race is greater than the radius of an adjacent race closer to the first end of the male member, and the number of balls in the first race is just one more than the number of balls in the adjacent race closer to the first end.

Description

[0001]This application is a continuation of U.S. patent application Ser. No. 08 / 742,520 filed on Nov. 1, 1996, <?insert-start id="INS-S-00002" date="20070619" ?>now U.S. Pat. No. 6,164,707<?insert-end id="INS-S-00002" ?>, which is a continuation of U.S. patent application Ser. No. 08 / 260,160 filed on Jun. 15, 1994, now abandoned, both of which applications are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The present invention relates to a swivel joint and, more particularly, to a swivel joint having stepped bearing races.[0003]Swivel joints are used in connect fluid pipes in oilfields and in other applications. Swivel joints are generally comprised of interfitting male and female members rotatably connected by a bearing assembly. Typically, inner and outer grooves are incorporated in the male and female members to form a bearing race, and a plurality of ball bearings are housed within the race. Higher demand for compatibility with increased s...

AI Technical Summary

Benefits of technology

[0005]The present invention improves sealing under extreme conditions and specifically eliminates bearing race brinelling at pressures much greater than is attained with conventional or known swivel joints with minimal increase in weight and cost. This stepped configuration more equally distributes hydrostatic end loading to each bearing race section, enabling maximum total end loading while minimizing load concentration on a particular bearing race. In addition, the stepped configuration permits the male member to have a relatively larger cross section under the bearing race without increasing the overall diameter of the swivel joint, which enables the male member to withstand a relatively greater amount erosive wear and thereby improves the overall integrity of the swivel joint.

Problems solved by technology

Even with multiple bearing races high pressures can sometimes cause deformation or brinelling of the bearing races.

Such brinelling relaxes the compression of the seal between the male and female members and causes the seal to leak, preventing the swivel joint from swiveling smoothly under pressure and reducing the bearing race life significantly.

In addition, errosive wear in the male member under the bearing race can quickly reduce the integrity of the swivel joint.

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