CA1161881A - Rotary joint - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A rotary joint utilizing a single anti-friction bearing interposed between the static and dynamic components wherein a self-aligning or floating seal is utilized to maintain effective sealing in the event of misalignment. The rotary joint includes a bearing supported sleeve to which a conduit adapter may be affixed in such a manner to mount and locate the bearing on the sleeve, and the components are economically manufactured wherein a dependable and efficient rotary joint may be produced at low cost.

Description

~ ~ B 1 88 ~

1. Rotary joints are utilized to establish communication

2. between a fixed conduit system and a rotating member, such as a

3. heating or cooling drum. The joint includes a housing having a

4. chamber defined therein having a port for communicating with a

5. ~ixed conduit system, and a rotary member, such as a sleeve or

6. nipple, is located within the housing and supported thereon by

7. bearings. Sealing means establish fluid tight seals between the

8. housing and the rotatable sleeve, and the sleeve is coaxially

9. aligned with the rotating member being serviced. With rotary

10. joints, the life and efficiency is related to the ability of the

11. seal to remain efficient and operative, and a wide variety of

12. sealing arrangements have been employed with rotary joints.

13. While rotary joints utilize both friction and anti-

14. friction bearings, it is highly desirable in many applications to

15. employ anti-friction bearings, and in such joints it is the prac-

16. tice to use a pair oE ball bearings mounted upon a tubular sleeve

17. axially spaced relative to each other in order to assure concen-

18. tricity of the sleeve to the bearing and housing during operation.

19. The use o~ a pair of ball bearings is expensive, but it is the

20. common practice to use the bearings in pairs in order to achieve

21. axial rigidity and prevent misalignment which would adversely af-

22. Eect the sealing as provided by known rotary join-t seal assemblies.

23. From a cost standpoint, it is preferable to use only

24. a single anti-~riction bearing in a rotary joint. However, dif-

25. ficulties encountered with respect to maintaining alignment be-

26. tween the rotary and stationary components with attendant pro-

27. blems o~ maintaining seal integrity render single anti-friction

28. bearing joints usable in only relatively few applications, and 2~. floating seals are sometimes used which have self-aligning capa-30. bilities.
31. It is an object oE the invention to provide a rotary ~2. joint utilizing a single anti-Eriction bearing between static and 1. ~;

fl8~

1. and dynamic components, and wherein self-aligning sealing appara-2. tus is employed which is of an economical cons-truction, and may 3. be readily installed.
4. An additional object of the invention is to provide 5. a rotary joint employing a single anti-friction bearing wherein 6. a floating and self-compensating seal assembly is used which 7. automatically accommodates itself to misalignment with respect 8. to the axis of joint rotation, and wherein wear is automatically 9. compensated for by means of biasing structure.
10. Yet an additional object of the invention is to pro-11. vide a rotary joint utilizing a single anti-friction bearing 12. wherein the bearing supports a rotating sleeve received within 13. the bearing inner race, and an adapter removably affixed to the 14. sleeve laterally engages the inner bearing race locating and 15. positively retaining the sleeve within the inner bearing race.
16. Additionally, an object of the invention pertains to 17. rotary joint structure wherein an economical joint may be pro-18. duced having a relatively wide range of self-alignment, and 19. wherein a variety of conduit attaching adapters associated with 20. an inner sleeve may be selectively mounted upon the sleeve, and 21. wherein the adapter aids in maintaining the sleeve in operative 22. relationship with anti-friction bearing means.
23. In the practice of the invention a housing includes 24. a chamber defined therein communicating with at least one port 25. associated with a fluid supply or discharge conduit. A single 26. anti-friction ball bearing is mounted within the housing chamber 27. and a tubular sleeve is located within the bearing inner race 28. and positively associated therewith by a threaded adapter mounted

29. upon the sleeve and engagin~ a lateral side of the inner bearing

30. race.

31. ~ seal assembly is interposed between th~ sleeve and

32. the housing havin~ a sealing surface which lies in a plane sub-1. stantially perpendicular to the sleeve axis of rotation, and the 2. sealing assembly includes an annular sealiny surface against which 3. an annular seal ring is biased by a compression spring. The seal ~1. ring is maintained in place by a resilient elastomer support ring 5. slidably supported within the housing, and this resilient support 6. ring permits the seal ring to compensate for deviation of the 7. sealing surface from the true axis of rotation, the elastomer per-8. mitting the seal ring to maintain a sealing relationship with the 9. sealing surface defined on the sleeve, and the spring insuring an 10~ effective seal between the seal ring and sealing surface regard-11. less of whether the rotation of the sleeve is true.
12. A radially extending shoulder is defined upon the 13. sleeve adapted to engage a lateral edge of the inner bearing ring, 14. and a conduit adapter threaded upon the sleeve engages the opposite 15. bearing inner race lateral edge whereby threading the adapter upon 16. the sleeve positively locks and positions the sleeve relative to 17. the bearing inner race. The adapter may take any desired form, 18. such as male threaded, female threaded, or the like, and the en-19. tire rotary joint apparatus is of an economical construction 20. which may be readily manu~actured by high production techniques.
21. The aforementioned objects and advantages of the in-22. vention will be appreciated from the following description and 23. accompanying drawings wherein:
2~. Fig. 1 is a diametrical, elevational, sectional 25. view of a rotary joint in accord with the invention, 26. Fig. 2 is an enlarged, detail, diametrical, eleva-27. tional, sectional view of the seal assembly, 28. Fig. 3 is a de-tail, elevational, sectional diametri-29. cal view of the rotary joint illustrating another embodiment of 3U. adapter, and 31. Fig. ~ is an enlarged, detail, elevational sectional 32~ view of a modification of seal assembly for use within high pres-1. sure installations.
2. With reference -to Figs. 1 and 2, a rotary joint in 3. accord with the invention includes a housing 10 which may be 4. formed of either metal or synthetic plastic. The housing in-5. cludes a passage 12 communicatin~ with threaded ports 14 and 16, 6. and if desired one of these ports may be plugged~ or conduits 7. associated therewith, not shown.
8. A chamber 18 is defined within the housing 10 and 9. is vented through vents 20. The chamber 18 includes a radial 10. shoulder 22 intersecting cylindrical surface 24, and a cylindrical 11. surface 26 intersecting radial shoulder 28 defines a bearing re-12. ceiving recess into which anti-friction ball bearing 30 is 13. mounted. A recess 32 receives a split retaining ring 34 engaging 14. a lateral side o~ the bearing outer race 36 whereby axial dis-15. placement of the bearing relative -to the housing 10 ls prevented.
16. A tubular sleeve 38 inclucles a cylindrical surface 17. closely received within the bearing inner race 40. Sleeve 38 18. includes a radial shoulder 42 enga~ed by one lateral side of the 19. inner race 40.
20. The sleeve 38 includes a recess 44 adapted to receive 21. a portion of -the seal assembly 46, and at the opposite end of the 22. sleeve external threads 48 are deEined upon whlch the adapter 50 23. is threaded.
24. The adapter 50 is of a tubular configuration having 25. internal threads which mate with the sleeve threads ~8, and the 26. end 52 of the adapter engages a lateral side of the bearing inner 27. race 40 forcing the inner race against -the sleeve shoulder 42 28. thereby firmly mounting the sleeve to the inner race. The adapter 2~. shown in ~ig. 1 is externally threaded at 54 whereby the adapter 30. may be threaded into an opening or a pipe coupling, not shown, 31. for association with drum related structure, or -the like.
32. The rotary jo:int seal assembly generally indicated 8~

1. at ~6 includes an annular elastic cushion 56 which is received 2. within the sleeve recess 44. The cushion 56, in turn, includes 3. a recess in which the annular circular seal element 58 is mounted 4. having a flat sealing surface 60 defined thereon which lies in a 5. plane perpendicularly disposed to the axis of the bearing 30 and 6. sleeve 38. The element 58 may be formed of ceramic, iron or 7. stainless steel.
8. A seal ring 62, which may be formed of synthetic 9. plastic or carbon, includes an annular projection 64 defining 10. a flat sealing surface 66 sealingly engaging the seal surface 11. 60. The seal ring 62 includes an axially extending cylindrical 12. surface 68 which intersects the radial surface 70, and these two 13. surfaces define a recess in which the annular static seal support 14. member 72 is received. The support meI~ber 72 is formed of an 15. elastic material and includes an outer cylindrical surface 74 16. which closely engages the housing cylindrical surface 24 in a 17. Erictional yet axiallv slldable, relat.ionship. The support mem-18. ber 72 is provided wi-th a tapered surface 76 defining a lip 78, 19. and likewise the portion 80 constitutes a lip whereby pressure 20. within the housing will ~orce the lips against the support sur-21. :Eaces 24 and 68 to produce fluid-tight seals therewith.
22. The support member 72 includes a radially extending 23. surface 82 against which the collar 84 of a spring assembly en-24. gages. A similar collar 86 engages the housing surface 22, and 25. compression spring 88 imposed between the collars will produce a 26. biasing force on the support member 72 and seal ring 62 toward 27. the right, Fig. 1, whic.h is substantially uniformly distributed 28. about the configuration oE the elastic support member 72.
29. In use, the adapter 50 is threaded into the drum or 30. other .rotating part to which pressurized Eluid medi~m is supplied, 31. or withdr~wn, and supply or exhau5t conduits are threaded into 32. the port or ports 14 or lfi of the housing 10. ~s the sleeve 38 1. rotates relative to the housing 10 the seal ring 62 will maintain 2. a sealed relationship with the sealing surface 60 due to the 3. flexible support of the seal ring provided by an elastomeric sup-4. port member 72. Assuming that a pressurized fluid is being tra.ns-5. mitted through the rotary joint, the fluid pressure exerted upon 6. the support member 72 will cause the support member and seal ring 7. 62 to function as a piston maintaining the seal ring in firm en-8. gagement with the seal surface 60, and if the sleeve 38 is slightly 9. out of alignment with the a~is of the ~earing 30 the nutating ac-10. tion of the seal ring 62 will be compensated for by the ability 11. of the seal ring to follow such erratic movement of the sealing 12. surface 60 because of the elastomeric character of support member 13. 72.
1~. The presence of the spring 88, and associated collars, 15. assures -that a tight sealing engagement between the seal ring 62 1~. and sealing surface 60 occurs even when the rotary joint is not 17. under pressure, or i a subatmospheric pressure exists within the 18. rotary joint. The frictional engagement o:E the support member 72 19. to the surface 24 eliminates the need for pins or keys to prevent 20. relative rotation, and the seal assembly components are of a sim-21. ple form which may be readily manufactured commercially at little 22. cost.
23. In Fig. 3 a modification of tubular adapter 90 is 24. illustrated having internal threads 92 for threading upon the 25.~ sleeve 38 as described above. However, the adapter 90 is inter-26. nally threaded for eliminating the need for a coupling.
27. In Fig. ~ a variation of seal assembly is shown which 28. is particularly suitable where very high pressures are transmitted 29. through the rotary joint. In Fig. ~, the annular element 9~ de-30. fining sealing surface 96 is not mounted wikhin a resilient cushion, 31. but an O-rin~ 98 is used to prevent the escape of fluid from around 32. the element. ~dditional:ly, a rigid washer 100 formed of metal, or l. the like, is located as illustrated, and may be either embedded 2. in the support member 72 or the support member 72 may be recessed 3. to accommodate -the same. The presence of the washer lOO pre-4. vents the elastic material of the support member from being 5. "extruded" past the seal ring 62.
6. It will be appreciated from the aforedescribed des-7. cription that the invention results in a low cost rotary joint of ~. simplified construction wherein a single anti-friction bearing 9. may be employed, and yet dependable and long wearing high sealing 10. efficiencies can be maintained.
11. It is appreciated that various modifications to the 12. inventive concep-ts may be apparent to those skilled in the art 13. without departing from the spirit and scope of the invention.

Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows;

1. A rotary joint comprising, in combination, an annular housing having a first port in communication with a chamber defined therein, a single annular anti-friction bearing mounted upon said housing within said chamber, a tubular sleeve mounted within said bearing for rotation within said chamber about an axis, a second port defined by said sleeve communicating with said chamber, an annular elastic cushion mounted on said sleeve adjacent said second port, an annular rigid seal element supported upon said cushion defining an annular radially disposed sealing surface defined on said sleeve concentric with said axis, an annular seal within said chamber concentric with said axis sealingly and slidably engaging said sealing sur-face, annular resilient seal support means sealed with re-spect to said housing flexibly supporting said annular seal and constituting the sole support of said seal whereby said seal is self-aligning with respect to said sealing surface, a cylindrical surface defined in said chamber coaxial to said axis, said seal support means comprising an elastomeric ring having a first lip seal portion sealingly engaging said cylindrical surface, a cylindrical surface defined on said annular seal coaxial to said axis, said ring having a second lip portion engaging said seal cylindrical surface wherein said seal is supported within said ring, fluid pressure within said housing biasing said seal into engagement with said sealing surface and said lip seals into sealing relation to to their associated cylindrical surface.

2. In a rotary joint as in claim 1, a spring within said chamber engaging said ring axially biasing said ring and seal toward said sealing surface.

3. In a rotary joint as in claim 1, an annular adapter releasably affixed to said sleeve in communciation with said second port, and conduit attachment means defined on said adapter.

4. In a rotary joint as in claim 3, an annular thread defined on said sleeve, said bearing including an inner race engaging a radial shoulder defined on said sleeve, threads defined on said adapter for mating with said sleeve threads, said adapter engaging said bearing inner race af-fixing said inner race to said sleeve.

5. In a rotary joint as in claim 1, an anti-extrusion rigid ring located between said seal and said elastomer ring to prevent extrusion of said elastomer due to the pressure within said housing.