WO1996023151A1 - Dispositif ameliore d'etancheite pour ressort de rappel d'un piston mu par pression fluide - Google Patents

Dispositif ameliore d'etancheite pour ressort de rappel d'un piston mu par pression fluide Download PDF

Info

Publication number
WO1996023151A1
WO1996023151A1 PCT/US1995/015755 US9515755W WO9623151A1 WO 1996023151 A1 WO1996023151 A1 WO 1996023151A1 US 9515755 W US9515755 W US 9515755W WO 9623151 A1 WO9623151 A1 WO 9623151A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
groove
radial
sealing lip
pressure
Prior art date
Application number
PCT/US1995/015755
Other languages
English (en)
Inventor
John A. Burke
Original Assignee
Greene, Tweed Of Delaware, Inc.
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 Greene, Tweed Of Delaware, Inc. filed Critical Greene, Tweed Of Delaware, Inc.
Priority to AU43738/96A priority Critical patent/AU4373896A/en
Publication of WO1996023151A1 publication Critical patent/WO1996023151A1/fr

Links

Classifications

    • 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
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/164—Sealings between relatively-moving surfaces the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid

Definitions

  • the present invention relates generally to spring seals, and more particularly, to an improved fluid pressure activated piston return spring seal that may be employed in a disc brake braking system to achieve increased piston bore stroke.
  • a spring seal assembly as described in the aforementioned references has a serious disadvantage in that the deflection of the seal element and the resultant stroke of the piston are limited. More specifically, since the seal element in toroidal cross-sectional has a generally planar pressure side or face, the maximum deflection of the seal element and the resultant maximum bore stroke of the piston is approximately ten percent (10%) of the seal cross- section, a value too small to meet performance requirements under some circumstances. In an effort to increase the seal element deflection and piston stroke of the aforementioned spring seal assembly, the dimensions of the seal element in toroidal cross-section were proportionally increased. However, the increased size seal element required increased fluid pressure for full deflection operation and otherwise did not provide adequate increased deflection and piston stroke.
  • annular groove has in toroidal cross-section first and second generally parallel radial side walls, an axial base wall extending between the first and second side walls, and a mouth.
  • the seal element has a generally annular shape and is formed of an elastomeric material.
  • the seal element has a toroida cross-section which includes first and second oppositely situated radial faces and an axial face.
  • the first radial face faces the first side wall, defines a pressure side of the seal element, and includes a notch extending inwardly with respect to the seal element and a base wall pressure sealing lip for sealingly engaging the base wall.
  • the axia face faces toward and partially protrudes through the mouth of the groove, and has a piston pressure sealing lip for sealingly engaging a piston positioned in the housing and across the mouth of the groove.
  • a first angled surface extends from the piston pressure sealing lip at a first angle with respect to the axis of the element and in a direction generally toward the second radial face to an intermediate point.
  • the piston pressure sealing lip is outside the groove and proximate the first radial face and the intermediate point is proximate the mouth of the groove.
  • a second angled surface extends from the intermediate point at a second angle with respect to the axis of the element larger than the first angle and in a direction generally toward the second radial face.
  • the piston pressure sealing lip and the piston move from a relaxed position to a pressurized position when sufficient fluid pressure is applied to the pressure side, and return from the pressurized position to the relaxed position when the fluid pressure is removed.
  • Fig. 1 is a toroidal cross-sectional view of a seal element employed in a first embodiment of a spring seal assembly
  • Fig. 2 is a toroidal cross-sectional view of the seal element shown in Fig. 1 positioned within a seal gland and compressed by a piston extending across the mouth of the gland to form the spring seal assembly;
  • Fig. 3 is a view similar to Fig. 2 showing the spring seal assembly under pressure
  • Fig. 4 is a toroidal cross-sectional view of a first and second seal element employed in a second embodiment of a spring seal assembly
  • Fig. 5 is a toroidal cross-sectional view of the first and second seal elements shown in Fig. 4 positioned within a seal gland and compressed by a piston extending across the mouth of the gland to form the spring seal assembly;
  • Fig. 6 is a view similar to Fig. 5 showing the spring seal assembly under pressure.
  • Fig. 1 a seal element 10 constructed in accordance with a first embodiment of the present invention.
  • the seal element 10 is annularly shaped and is formed from an elastomeric material.
  • the elastomeric material comprises a rubber material, although it will be recognized that other materials such as polymeric plastic may be employed without departing from the spirit and scope of the present invention.
  • a disc brake represents a typical environment in which the seal element 10 of the present invention may be incorporated to form a spring seal assembly 11 (as seen in Fig. 2) .
  • the brake is conventional and per se forms no part of the present invention.
  • a general description of the disc brake may be found in either of U.S. Patents Nos. 4,229,013 or 4,342,463.
  • the spring seal assembly 11 includes a piston housing 12 having a seal gland or groove 14. More particularly, the groove 14 has in toroidal cross-section first and second generally parallel radial side walls 16, 18, and an axial base wall 20 that extends between the first and second side walls 16, 18. The groove 14 is generally open and has a mouth 22 opposite the base wall 20.
  • the seal element 10 has a first radial face 24 that faces toward the first side wall 16 when the seal element 10 is positioned within the groove 14.
  • the first radial face 24 is the pressure side of the seal element 10 and accordingly when employed in a disc brake braking system is exposed to fluid pressure from a braking fluid (not shown) .
  • the braking fluid may typically be a gas such as compressed air or a liquid such as hydraulic brake fluid, hydraulic oil, or conventional engine oil.
  • other fluids such as water may be employed without departing from the spirit and scope of the present invention.
  • the first radial face 24 of the seal element 10 has a notch 26 extending into the seal element 10.
  • the first radial face includes first and second generally flat, radial surfaces 30, 32, one on either side of the notch 26.
  • the notch 26 is defined by a first angled portion 34 that extends from the first radial surface 30 into the seal element 10 to a generally inwardly rounded crotch 36 at the innermost portion of the notch 26, and a second angled portion 38 that extends from the second radia surface 32 into the seal element 10 to the rounded crotch 36.
  • a first angled portion 34 that extends from the first radial surface 30 into the seal element 10 to a generally inwardly rounded crotch 36 at the innermost portion of the notch 26, and a second angled portion 38 that extends from the second radia surface 32 into the seal element 10 to the rounded crotch 36.
  • the first and second angled portions 34, 38 respectively extend at angles ⁇ , ⁇ with respect to a line running perpendicular to the axis 45 of the seal element 10.
  • the angle ⁇ ranges between about 30 and 60 degrees and the angle ⁇ ranges between abou 50 and 70 degrees, although it is preferable that angle ⁇ b about 45 degrees and that angle ⁇ be about 60 degrees.
  • the first radial face 24 also has a base wall pressure sealing lip 28 that sealingly engages the base wal 20 to seal the fluid and prevent the fluid from moving past the seal element 10 along the base wall 20.
  • the base wall pressure sealing lip 28 and the second angled portion 38 of the notch 26 form a static leg 39.
  • the static leg 39 juts toward the first side wall 16 and sealingly engages the bas wall 20 of the groove 14 when the seal element 10 is installed in the groove 14.
  • the compression increases the sealing engagement of the static leg 39 with the base wall 20 and causes the static leg 39 to bend towar the mouth 22 of the groove 14.
  • the seal element 10 also has a second radial face 40 opposite the first radial face 24 and facing the second side wall 18.
  • the secon side wall 18 extends a distance D ⁇ from the base wall 20 to the mouth 22 of the groove 14, and the second radial face 4 extends a distance D 2 from the base wall 20 toward the mouth 22 of the groove 14, such that the distance D 2 is approximately one-quarter the distance D x .
  • the second radial face 40 of the seal element 10 engages the second side wall 18 of the groove 14 and stabilizes the sea element 10 during pressurization and deflection.
  • the seal element 10 also has a generally axial surface 41 extending between the second radial face 40 and the static leg 39 to aid in stabilizing the seal element 10 during pressurization and deflection. As seen in Figs. 2 and 3, the axial surface 41, is adjacent the base wall 20 when the seal element 10 is compressed by the piston 46 and is moved into substantially complete contact with the base wall 20 when sufficient fluid pressure (P) is applied.
  • the seal element 10 has an axial face 42 that faces toward and partially protrudes through the mouth 22 of the groove 14 (as seen in Fig. 2) .
  • the axial face 42 has a piston pressure sealing lip 44 that engages a piston 46 positioned within the housing 12 and across the mouth 22 of the groove 14.
  • the piston pressure sealing lip 44 sealingly engages the piston 46 to prevent sealing fluid from moving past the seal element 10 along the piston 46, and grips and moves with the piston 46 when the piston 46 and the seal assembly 11 are pressurized.
  • the piston pressure sealing lip 44 and the first angled portion 34 of the notch 26 form a dynamic leg 47.
  • the dynamic leg 47 juts toward the first side wall 16 and out of the mouth 22 of the groove 14 when the seal element 10 is installed in the groove 14.
  • the compression causes the dynamic leg 47 to bend toward the base wall 20 of the groove 14.
  • the axial face 42 has first and second angled surfaces 48, 52.
  • the first angled surface 48 extends from the piston pressure sealing lip 44 in a direction toward the second radial face 40 and to an intermediate point 50.
  • the first angled surface 48 extends at an angle x with respect to a line parallel to the axis 45 of the seal element 10.
  • the angle ⁇ ranges between about 5 and 15 degrees, although it is preferable that angle a be about 10 degrees.
  • the piston pressure sealing l 44 is outside the groove 14 and is proximate the first radial face 24 of the seal element 10, and the intermediat point 50 is proximate the mouth 22 of the groove 14. Accordingly, when the seal element 10 is positioned within the groove 14 and the piston 46 compresses the seal elemen 10 toward the base wall 20 of the groove 14, the first angled surface 48 substantially completely contacts the piston 46 and grips the piston 46 along with the piston pressure sealing lip 44, and the dynamic and static legs 4 39 are forced toward one another to decrease the toroidal cross-sectional area of the notch 26.
  • the second angled surface 52 of the axial face 42 extends from the intermediate point 50 and in a direction generally toward the second radial face 40.
  • the second angled surface 52 extends at a second angle ⁇ with respect to a line parallel to the axis 45 of the seal element 10.
  • the angle ⁇ does not appreciably change.
  • the angle ranges between about 60 and 80 degrees, although it is preferable that angle ⁇ be about 70 degrees.
  • the second angled surface 52 extends from the intermediate point 50 to the second radial face 40, and the juncture of the second angled surface 52 and the second radial face 40 is adjacent the second side wall 18.
  • a generally wedge-shaped spring gap 54 opening toward the mouth 22 of the groove 14 is formed between the second angled surface 52 and the second side wall 18.
  • the spring-loaded elastomeric material When the fluid pressure (P) is removed, the spring-loaded elastomeric material returns to an unloaded shape according to the memory of the material, the spring gap 52 re-opens and the piston pressure sealing lip 44 and the piston 46 return from the pressurized position of Fig. 3 to the relaxed position of Fig. 2.
  • the amount of deflection of the piston pressure sealing lip 44 and the corresponding stroke of the piston 46 during a pressurization / de-pressurization cycle is substantially equal to the distance D 3 from the intermediate point 50 to the juncture of the second side wall 18 and the mouth 22 of the groove 14 (as seen in Fig. 2) .
  • the amount of deflection and stroke that may be achieved by the seal assembly 11 and the piston 46 is dependent upon the shape of the groove 14, the notch 26, and the spring gap 54, the angle a of the first angled surface 48, the second angle ⁇ of the second angled surface 52, and the amount of fluid pressure applied against the pressure side of the seal element 10, among other things.
  • the type and flexibility of the material employed to construct the seal element 10 and the various linear dimensions of the seal element 10 also contribute to the amount of deflection and piston stroke achievable.
  • a 0.1 inch deflection and piston stroke may be achieved with a groove 14 that is 0.47 inches wide and 0.375 inches deep (distance D ; with a seal element 10 constructed of nitrile elastomer and having an angle a of 10 degrees, an angle ⁇ of 70 degrees, and a spring gap distance D 3 of 0.105 inches; and with a notch 26 in the seal element 10 having angles ⁇ , ⁇ of 45 and 60 degrees, respectively, and a rounded crotch 36 that is about 0.16 axial inches within the notch 26 and 0.2 radial inches from the base wall pressure sealing lip 28, when such a seal assembly 11 is pressurized to about 1,500 PSI.
  • the axial face 42 of the seal element 10 may also have a third angled surface 56 (as best seen in Fig. 1) extending from the piston pressure sealing lip 44 in a direction generally toward the first radial face 24.
  • the third angled surface 56 is useful under certain circumstances as an assembly lead-in chamfer. However, the third angled surface 56 is not necessary for assembly insertion of a conventional piston and may actually be undesirable under other circumstances. If undesirable or unnecessary, the third angled surface 56 may be deleted by extending the first angled surface 48 and the first radial surface 30 to meet at the piston pressure sealing lip 44.
  • first and second seal elements 60, 66 of a spring seal assembly 58 constructed in accordance with a second preferred embodiment of the present invention.
  • the first element 60 is substantially similar to the seal element 10 of the first embodiment of the present invention.
  • the first element 60 differs from the seal element 10 in that the first element 60 also includes a generally inwardly curved portion 62 extending from the second angled surface 52 toward the second radial face 40. Accordingly, the rounded surface 62 and the second radial face 40 define a pedestal 64.
  • the second element 66 is generally annularly shaped, is formed of a non-elastomeric anti- extrusion material, and has an axis 67 generally coinciding with the axis 45 of the first element 60.
  • the second element 66 is an anti-extrusion ring and is positioned generally within the groove 14 on the pedestal 64 and between the second angled surface 52 and a portion of the second side wall 18 adjacent the mouth 22 of the groove 14.
  • the second element 66 may have a generally rectilinear shape in toroidal cross-section.
  • the second element 66 has a generally outwardly curved portion 70 that is complementarily received by the rounded surface 62.
  • the anti-extrusion ring or second element 66 is formed from a non-elastomeric material such as polytetrafluoroethylene (PTFE) thermoplastic or nylon plastic.
  • PTFE polytetrafluoroethylene
  • PEEK polyetheretherketone
  • the second element or anti-extrusion ring 66 is employed when high pressure above approximately 1,500 PSI is applied to the spring seal assembly 58.
  • a liquid sealing fluid such as ABF brake fluid is employed to exert such high pressure.
  • the piston 46 is positioned across the mouth 22 of the groove 14, and the first and second elements 60, 66 are not pressurized, the second element 66 preferably does not contact the piston 46 in an interference fit.
  • pressure (P) is applied, as seen in Fig.
  • the pressure (P) causes the pedestal 64 to exert a generally radial force against the anti-extrusion ring 66 and the ring 66 sealingly contacts the piston 46. Accordingly, the anti-extrusion ring 66 prevents the first element 60 from being extruded through the gap between the piston 46 and the housing 12 under the force of the high pressure (P) .
  • the second embodiment preferably has a generally wedge-shaped spring gap 72 (as seen in Fig. 5) .
  • the spring gap 72 in the second embodiment is formed between the second element 66 and the second angled surface 52 of the first element 60.
  • the spring gap 72 substantially closes when a sufficient fluid pressure (P) is applied at the first radial face or pressure side 24 of the first element 60 (Fig. 5) and reopens when the fluid pressure (P) is removed (Fig. 6) .
  • the spring seal assembly 58 of the second embodiment of the present invention operates in the same manner as the spring seal assembly 11 of the first embodiment .
  • a separate piston return spring is not required and the groove 14 is a standard seal groove requiring no special machining or shape.
  • the spring seal assembly 11 or 58 of the present invention may be employed as a male or female seal assembly so long as the assembly is stationary with respect to the piston housing 12.
  • the present invention comprises an improved fluid pressure activated piston return spring seal element for installation in a piston housing comprising an annular groove.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Sealing Devices (AREA)

Abstract

L'invention concerne un dispositif amélioré d'étanchéité pour ressort de rappel mû par pression fluide à installer dans une gorge annulaire d'un carter de piston. Cette gorge annulaire comporte deux parois latérales radiales, une paroi d'assise axiale et une embouchure. L'élément d'étanchéité comporte un organe de forme annulaire portant, sur sa section transversale toroïdale, une première (24) et une seconde (40) face radiale placées en opposition, ainsi qu'une face axiale (42). La première de celles-là (24), qui délimite un côté de l'élément soumis à la pression comporte une encoche (26), se formant vers l'intérieur de l'élément et une lèvre d'étanchéité (28) sur la paroi d'assise axiale soumise à la pression. La face axiale (42), qui déborde partiellement d'un bout à l'autre de l'embouchure de la gorge, possède une lèvre d'étanchéité (44), soumise à la pression du piston, une première surface angulaire (48), s'étendant de la lèvre (44), selon un premier angle, à un point intermédiaire (50) et une seconde surface angulaire (52) partant de ce point, selon un second angle plus ouvert que le premier, pour aboutir à la seconde face radiale (40). Lorsque l'élément d'étanchéité est mis en place dans la gorge, la lèvre d'étanchéité soumise à la pression du piston se trouve à l'extérieur de la gorge et proche de la première face radiale tandis que le point intermédiaire est proche de l'embouchure de la gorge. La lèvre d'étanchéité soumise à la pression du piston ainsi que celui-ci se déplacent d'une position de repos à une position sous pression lorsqu'une pression fluide suffisante est appliquée sur le côté soumis à la pression et reviennent à leur position de repos lorsqu'il n'y a plus de pression.
PCT/US1995/015755 1995-01-23 1995-12-05 Dispositif ameliore d'etancheite pour ressort de rappel d'un piston mu par pression fluide WO1996023151A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU43738/96A AU4373896A (en) 1995-01-23 1995-12-05 Improved fluid pressure activated piston return spring seal

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37651195A 1995-01-23 1995-01-23
US376,511 1995-01-23

Publications (1)

Publication Number Publication Date
WO1996023151A1 true WO1996023151A1 (fr) 1996-08-01

Family

ID=23485314

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/015755 WO1996023151A1 (fr) 1995-01-23 1995-12-05 Dispositif ameliore d'etancheite pour ressort de rappel d'un piston mu par pression fluide

Country Status (2)

Country Link
AU (1) AU4373896A (fr)
WO (1) WO1996023151A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1167807A2 (fr) * 2000-06-30 2002-01-02 Shimano Inc. Bague ou joint d'étanchéité de type "roll-back" pour frein à disque

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3271038A (en) * 1962-10-30 1966-09-06 Dowty Seals Ltd Sealing devices
GB2029913A (en) * 1978-09-11 1980-03-26 Bestobell Seals Ltd Sealing ring assemblies
US4229013A (en) * 1979-07-02 1980-10-21 Greene, Tweed & Co., Inc. Spring seal
US4342463A (en) * 1980-10-16 1982-08-03 Green, Tweed & Co., Inc. Spring seal
US4345771A (en) * 1977-07-15 1982-08-24 Aisin Seiki Kabushiki Kaisha Sealing cup for hydraulic piston-cylinder device
US4417503A (en) * 1977-08-20 1983-11-29 Tokico Ltd. Cylinder device
US4893823A (en) * 1988-12-21 1990-01-16 Greene, Tweed & Co. Seal assembly
US5205568A (en) * 1991-03-14 1993-04-27 Festo Kg Sealing ring
US5431415A (en) * 1993-11-15 1995-07-11 Greene Tweed Of Delaware, Inc. Seal with acute heel angle

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3271038A (en) * 1962-10-30 1966-09-06 Dowty Seals Ltd Sealing devices
US4345771A (en) * 1977-07-15 1982-08-24 Aisin Seiki Kabushiki Kaisha Sealing cup for hydraulic piston-cylinder device
US4417503A (en) * 1977-08-20 1983-11-29 Tokico Ltd. Cylinder device
GB2029913A (en) * 1978-09-11 1980-03-26 Bestobell Seals Ltd Sealing ring assemblies
US4229013A (en) * 1979-07-02 1980-10-21 Greene, Tweed & Co., Inc. Spring seal
US4342463A (en) * 1980-10-16 1982-08-03 Green, Tweed & Co., Inc. Spring seal
US4893823A (en) * 1988-12-21 1990-01-16 Greene, Tweed & Co. Seal assembly
US5205568A (en) * 1991-03-14 1993-04-27 Festo Kg Sealing ring
US5431415A (en) * 1993-11-15 1995-07-11 Greene Tweed Of Delaware, Inc. Seal with acute heel angle

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1167807A2 (fr) * 2000-06-30 2002-01-02 Shimano Inc. Bague ou joint d'étanchéité de type "roll-back" pour frein à disque
EP1167807A3 (fr) * 2000-06-30 2003-01-22 Shimano Inc. Bague ou joint d'étanchéité de type "roll-back" pour frein à disque

Also Published As

Publication number Publication date
AU4373896A (en) 1996-08-14

Similar Documents

Publication Publication Date Title
US5472216A (en) Seal ring for valve stem
US5131666A (en) Zero clearance anti-extrusion rings for containment of ptfe packing
US4053166A (en) Two-piece seal
JP3242428B2 (ja) 流体弁
US5431415A (en) Seal with acute heel angle
US6007070A (en) Pressure actuated packing assembly
US4635945A (en) Anti-extrusion seal with primary and secondary complementary elements
US5040804A (en) Lip seal with unitized support ring
US7793944B2 (en) Sealing device
US4840379A (en) Split sealing ring having a bias cut
EP0730713B1 (fr) Unite de jointure etanche
US5575484A (en) Fluid pressure activated piston return spring seal
CA2348973C (fr) Ensemble double garniture d'etancheite
US4053163A (en) Seal construction
US3521893A (en) Nonextrusion ring
US3612551A (en) Bidirectional lip seal
US4421330A (en) Antifriction fluid seal assembly
US3897957A (en) Ring seal, assembly and method of manufacturing
US6340161B1 (en) Machinery seal
EP0424372B1 (fr) Joint d'etancheite combine servant a assurer l'etancheite entre deux pieces mecaniques
US6648337B1 (en) Backup ring with controlled spacing
US4109924A (en) Stepped joint piston ring
US5092610A (en) High pressure piston seal
US6158744A (en) Seal arrangement providing a seal between a bore and a rod movable in the bore
US4991857A (en) Stuffing box assembly

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU IS JP KE KG KP KR KZ LK LR LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TT UA UG UZ VN

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase