GB2261920A - A method of making a seal - Google Patents

A method of making a seal Download PDF

Info

Publication number
GB2261920A
GB2261920A GB9125477A GB9125477A GB2261920A GB 2261920 A GB2261920 A GB 2261920A GB 9125477 A GB9125477 A GB 9125477A GB 9125477 A GB9125477 A GB 9125477A GB 2261920 A GB2261920 A GB 2261920A
Authority
GB
United Kingdom
Prior art keywords
seal
groove
former
blank
relative motion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9125477A
Other versions
GB2261920B (en
GB9125477D0 (en
Inventor
David Henry Roberts
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dowty Seals Ltd
Original Assignee
Dowty Seals Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dowty Seals Ltd filed Critical Dowty Seals Ltd
Priority to GB9125477A priority Critical patent/GB2261920B/en
Publication of GB9125477D0 publication Critical patent/GB9125477D0/en
Priority to PCT/GB1992/002168 priority patent/WO1993010964A1/en
Priority to CN 92114162 priority patent/CN1073386A/en
Publication of GB2261920A publication Critical patent/GB2261920A/en
Application granted granted Critical
Publication of GB2261920B publication Critical patent/GB2261920B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D99/00—Subject matter not provided for in other groups of this subclass
    • B29D99/0053—Producing sealings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
    • B21H7/00—Making articles not provided for in the preceding groups, e.g. agricultural tools, dinner forks, knives, spoons
    • B21H7/18—Making articles not provided for in the preceding groups, e.g. agricultural tools, dinner forks, knives, spoons grooved pins; Rolling grooves, e.g. oil grooves, in articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
    • B26D3/00—Cutting work characterised by the nature of the cut made; Apparatus therefor
    • B26D3/08—Making a superficial cut in the surface of the work without removal of material, e.g. scoring, incising
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/007—Forming single grooves or ribs, e.g. tear lines, weak spots
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
    • B29C59/04—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/26—Sealing devices, e.g. packaging for pistons or pipe joints

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Agronomy & Crop Science (AREA)
  • Forests & Forestry (AREA)
  • Sealing Devices (AREA)
  • Sealing With Elastic Sealing Lips (AREA)

Abstract

A grooved seal is formed by pressing a groove former (6) into an end face (5) of a seal blank and causing relative motion between the blank and the former (6). The former (6) takes the form of a rotatably mounted wheel held in a holder (8) which is caused to rotate by the relative motion. The groove (10) is thus formed by a crushing action which imparts a fine surface texture on the groove (10).

Description

A METHOD OF MAKING A SEAL This invention relates to a method of making a seal, in particular, a grooved seal.
Grooved seals are often used to form a seal about rotating shafts of machines. The grooves give an hydrodynamic effect which drives lubricant away from the seal. In the past these grooves have been machined into the seal material using a sharp cutting tool. However, the resultant grooves have had a coarse surface texture which retains a film of lubricant in the groove. Eventually, the retained oil burns onto the surface and the groove becomes choked and ineffective.
For some glass filled seal materials, the cutting tool is blunted after cutting grooves in a modest number of elements. If a blunt tool is used to cut further grooves, tearing and chipping can occur in the seal material producing a poor quality groove leading to premature failure.
Even whilst the tool is sharp, burring can occur requiring a further operation to be carried out to remove the burs.
It is an object of the invention to provide a method for forming a groove in a seal with a finer surface texture.
Accordingly the invention provides a method of making a grooved seal comprising the steps of providing a seal blank, providing a rotatably mounted groove former, pressing the former and seal blank into contact and causing relative motion of the former and seal blank to form a groove in the blank, the relative motion causing a rotational movement of the former.
By using a rotatably mounted groove former, the groove is formed by a crushing action in the material as opposed to a cutting action. The groove texture is, as a result, smoother and tearing and chipping is less likely to occur.
Preferably, the groove former is a wheel rotatably mounted in a holder.
The groove former will comprise a hard material of a cross section matching that of the required groove and, preferably, will comprise a tungsten carbide metal alloy.
A specific embodiment of the invention will now be described, by way of example only, with reference to the drawing in which: Figures 1 to 4 show a method of making a seal in accordance with the invention; and Figure 5 shows, in plan view, a seal groove forming tool in accordance with the invention.
With reference to Figure 1, a cylindrical rod 1 formed of polytetrafluoroethylene, PTFE, filled with 5% glass and 5% MoS2 is removably mounted in a lathe chuck 2. The outside diameter and inside diameter of the rod has been formed in a previous lathing operation well known to those skilled in the art. The lathe chuck 2 rotates the cylindrical rod 1 about central longitudinal axis 3.
As the chuck 2 rotates, a groove forming tool 4 is brought into contact with a planar annular end face 5 of the rod 1 and then pressed axially into the material. Progressively, the tool 4 is moved radially inwards, towards the axis 3 from distance X to distance Y from the axis 3.
As the tool 4 approaches Y, the pressure is gradually removed to form a helical groove centred on axis 3 with a gradual groove run out, that is to say, the depth of the groove gradually decreases as it approaches V.
As shown in Figure 2, the tool 4 comprises a tungsten carbide rolling wheel 6 rotatably mounted about an axle 7 in a wheel holder 8. The wheel 6 has a tapering edge 9 to form the desired crosssection of groove 10, as more clearly shown in Figure 3.
The seal is completed by a parting operation in which a cutting tool 11 is brought radially inwards, starting from a point the desired thickness Z of the finished seal from the end face 5, towards the axis 3 as shown in Figure 4. To form the next seal the cut end face of the remaining stock is machined flat and true and the previously described operations repeated.
A preferred form of seal groove forming tool is shown in Figure 5 and it comprises a holder 12 having a selectively rotatable carriage 13 mounted by a stud 14 at one end. The carriage 13 is retained by the stud in a generally circular recess 15 in the holder 12. Rotatably mounted in the carriage 13 are four tungsten carbide wheels 16, 17, 18 and 19. When wheel 16 has worn, the carriage 13 is rotated clockwise until unused wheel 17 is in position for use. Likewise, wheel 17 may be replaced by wheel 18 and wheel 18 by wheel 19.
In a test of two seals 896-008-7280-00 formed according to the invention, the seals were used to seal a shaft running at 6,000 r.p.m. at 1200C.
The lubricant used was B.P. UF7 which after 400 hours did not leak past the seal. No signs of burnt oil were found on the seals after completion of the test.
A further test was carried out to examine whether or not the groove would recover from the crushing action of the former.
A completed seal was placed in an air oven at 2000C for a period of 24 hours. Examination of the seal showed that material recovery had been minimal.

Claims (5)

1. A method of making a grooved seal comprising the steps of providing a seal blank, providing a rotatably mounted groove former, pressing the former and seal blank into contact and causing relative motion of the former and seal blank to form a groove in the blank, the relative motion causing a rotational movement of the former.
2. A method substantially as hereinbefore described with reference to the drawings.
3. A seal groove forming tool comprising a rotatably mounted groove former to, in use, be pressed into a surface of a seal blank relative motion of the tool and blank causing rotational movement of the former.
4. A tool as claimed in claim 2, wherein the groove former comprises a tungsten carbide wheel.
5. A seal groove forming tool substantially as hereinbefore described with reference to the drawings.
GB9125477A 1991-11-29 1991-11-29 A method of making a seal Expired - Fee Related GB2261920B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB9125477A GB2261920B (en) 1991-11-29 1991-11-29 A method of making a seal
PCT/GB1992/002168 WO1993010964A1 (en) 1991-11-29 1992-11-24 A method of making a seal
CN 92114162 CN1073386A (en) 1991-11-29 1992-11-28 The method of processing sealing

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9125477A GB2261920B (en) 1991-11-29 1991-11-29 A method of making a seal

Publications (3)

Publication Number Publication Date
GB9125477D0 GB9125477D0 (en) 1992-01-29
GB2261920A true GB2261920A (en) 1993-06-02
GB2261920B GB2261920B (en) 1995-04-26

Family

ID=10705481

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9125477A Expired - Fee Related GB2261920B (en) 1991-11-29 1991-11-29 A method of making a seal

Country Status (3)

Country Link
CN (1) CN1073386A (en)
GB (1) GB2261920B (en)
WO (1) WO1993010964A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1448920A2 (en) * 2001-11-28 2004-08-25 Federal-Mogul Corporation Hydrodynamic seal and method of making the same
US7938405B2 (en) 2005-04-22 2011-05-10 Vr-Dichtungen Gmbh Radial shaft sealing ring

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1522722A (en) * 1975-02-04 1978-08-31 Federal Mogul Corp Method of making sealing elements
US4243235A (en) * 1979-07-02 1981-01-06 The Mather Company Composite polytetrafluoroethylene and elastomer lip seal
US4542573A (en) * 1984-09-28 1985-09-24 The Fluorocarbon Company Method of producing a hydrodynamic seal

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1988738A (en) * 1931-05-25 1935-01-22 Charles E Johnson Process of making piston rings
FR1421558A (en) * 1964-11-05 1965-12-17 New process for modifying the outer shape of a plastic object and the internal tensions in this object
US3735615A (en) * 1970-05-19 1973-05-29 J Shneider Method of making grooves on surface of articles and device for its realization
US3857156A (en) * 1973-12-19 1974-12-31 Federal Mogul Corp Method of making tetrafluoroethylene sealing elements with hydrodynamic action
DE2421936B2 (en) * 1974-05-07 1976-06-10 Speidel-Kunststoffwerk Kg, 7404 Ofterdingen PROCESS FOR JOINT-TO-JOINT JOINT OF THE EDGES OF SPATIAL CURVED SHELL ELEMENTS MADE OF GLASS FIBER REINFORCED PLASTIC AND DEVICE FOR THEM
US4385429A (en) * 1979-07-18 1983-05-31 Dynetics, Inc. Method of manufacturing a clutch plate
US4450614A (en) * 1982-02-19 1984-05-29 Microdot Inc. Method of making a polytetrafluoroethylene hydrodynamic seal
US5048382A (en) * 1989-08-23 1991-09-17 Mar Don Corporation Method for making elastomeric sealing device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1522722A (en) * 1975-02-04 1978-08-31 Federal Mogul Corp Method of making sealing elements
US4243235A (en) * 1979-07-02 1981-01-06 The Mather Company Composite polytetrafluoroethylene and elastomer lip seal
US4542573A (en) * 1984-09-28 1985-09-24 The Fluorocarbon Company Method of producing a hydrodynamic seal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1448920A2 (en) * 2001-11-28 2004-08-25 Federal-Mogul Corporation Hydrodynamic seal and method of making the same
EP1448920A4 (en) * 2001-11-28 2006-06-14 Federal Mogul Corp Hydrodynamic seal and method of making the same
US7938405B2 (en) 2005-04-22 2011-05-10 Vr-Dichtungen Gmbh Radial shaft sealing ring

Also Published As

Publication number Publication date
GB2261920B (en) 1995-04-26
WO1993010964A1 (en) 1993-06-10
GB9125477D0 (en) 1992-01-29
CN1073386A (en) 1993-06-23

Similar Documents

Publication Publication Date Title
US4126064A (en) Preparation of annular blanks from tube stock
US3435502A (en) Piston ring and method of manufacture thereof
US2105896A (en) Method and means for honing gears, and for truing the honing means
US4611509A (en) Method of manufacturing a dental root canal cutting tool and apparatus therefor
US3994251A (en) Apparatus and method for trimming and deburring the edges of cylindrical metal bodies
US3952179A (en) Rotary cutting die and method for its production
US3905283A (en) Improved rotary cutting die
US4744277A (en) Method and device for cutting pipe lengths
EP1330339B1 (en) Method and apparatus for making a cutting tool having a plurality of margins
GB2261920A (en) A method of making a seal
EP1322448B1 (en) Method and apparatus for making a cutting tool having a flute
US2232843A (en) Method and means for burnishing spherical seats
JPH01130822A (en) Method for working surface of metallic pipe
US1944380A (en) Method of and means for bushing openings
US3691898A (en) Edge burr removal apparatus
US3293988A (en) Method and apparatus for broaching gears
GB2195928A (en) Method of cutting a surface of a work-piece
US4398078A (en) Finishing of annular articles
US1118784A (en) Manufacture of piston-packings.
EP0316105A1 (en) Endmill
JPS60232857A (en) High-speed profile milling method and device for rotatory symmetric workpiece
JP4431244B2 (en) Method for machining dynamic pressure generating groove in hydrodynamic bearing
US1881652A (en) Method of making alpha ring joint
GB2072069A (en) Method and machine for finishing a worm screw thread
RU2100179C1 (en) Method of shaping grinding wheel

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20001129