US3873249A - Seal for rotary combustion engine - Google Patents

Seal for rotary combustion engine Download PDF

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Publication number
US3873249A
US3873249A US400282A US40028273A US3873249A US 3873249 A US3873249 A US 3873249A US 400282 A US400282 A US 400282A US 40028273 A US40028273 A US 40028273A US 3873249 A US3873249 A US 3873249A
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US
United States
Prior art keywords
seal
apex
rotor
groove
slots
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.)
Expired - Lifetime
Application number
US400282A
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English (en)
Inventor
Vemulapalli D N Rao
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.)
Ford Motor Co
Original Assignee
Ford Motor Co
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 Ford Motor Co filed Critical Ford Motor Co
Priority to US400282A priority Critical patent/US3873249A/en
Priority to GB3824174A priority patent/GB1453177A/en
Priority to CA208,609A priority patent/CA1029666A/en
Priority to DE19742444278 priority patent/DE2444278A1/de
Priority to JP10894474A priority patent/JPS554928B2/ja
Application granted granted Critical
Publication of US3873249A publication Critical patent/US3873249A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
    • F01C21/08—Rotary pistons
    • F01C21/0809—Construction of vanes or vane holders
    • F01C21/0881—Construction of vanes or vane holders the vanes consisting of two or more parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C19/00—Sealing arrangements in rotary-piston machines or engines
    • F01C19/02—Radially-movable sealings for working fluids

Definitions

  • a sealing system for a rotary combustion engine includes an apex seal.
  • the apex seal comprises a graphite block having longitudinal slots or cuts along each lateral side for the purpose of providing flexibility.
  • the base of the seal is se cured in a seal receiving groove in the engines rotor and the radial resiliency of the seal itself urges the seal into contact with the rotor housing.
  • the present invention relates to apex seals for rotary combustion engine, and more particularly to seals for rotary engines having a trochoid rotor housing and a rotor-of generally triangular shape fitted within the housing and eccentrically mounted on an eccentric shaft.
  • an apex seal is provided that uses conventional materials, is of inexpensive construction and provides superior performance.
  • an apex seal for a rotary combustion engine is formed from a graphite block and has longitudinally extending slots along its lateral sides which increase the effective flexibility of the seal.
  • the apex seal is fitted in a seal receiving groove at one of the apexes of the rotor.
  • a longitudinally extending pin that is radially stationary with respect to the rotor holds the base of the seal in the groove.
  • the bottom of the groove is filled with an expanded silicone sponge and provides a gastight seal between the depth of the seal receiving groove and the base of the apex seal.
  • the outer longitudinal edge of the seal is provided with a groove that is filled with a friction reducing polymer that is constructed to smear the trochoid surface of the rotor housing.
  • the polymer may be polyarylsulfone.
  • FIG. 1 is a perspective view of a unique apex seal
  • FIG. 2 is an elevational view, partly in section, of the apex seal fitted in the apex groove of a rotor or rotary piston and engaging the trochoidal wall ofa rotor housing;
  • FIG. 3 is an enlarged view of a portion of the apex seal of FIGS. 1 and 2;
  • FIG. 4 is an end elevational view, partly in section, of the apex seal, the rotor and the rotor housing showing the seal flexed under the effects of prevailing forces;
  • FIG. 5 is an elevational end view, partly in section, similar to FIG.- 4 showing the seal flexed in the opposite direction under the effects of prevailing forces.
  • the conventional rotary combustion engine includes a rotor housing having an internal surface that is machined to the shape of an epitrochoid.
  • a generally triangular shape rotor or rotary piston is eccentrically mounted on an eccentric shaft that is supported'within the trochoid housing.
  • the conventional rotary engine includes a sealing system that provides gas-tight seals between the rotor, the housing side walls and the trochoid surface of the housing.
  • the sealing system includes side seals, corner seals and apex seals, all of which are carried by the rotor.
  • the apex seals are fitted into longitudinally extending seal receiving grooves at the apexes of the rotor and engage the trochoid surface.
  • the corner seals are of generally cylindrical shape and are fitted within cylindrical recesses in the end faces of the rotor at each end of the apex seal.
  • the corner seals engage the end wall of the rotor housing and are displaceable only axially in their recesses.
  • the side seals are of strip form and interconnect the corner seals. These seals fit within grooves in the I end faces of the rotor.
  • the present invention is particularly directed to the construction of a unique apex seal and to the manner in which it cooperates with the rotor groove and the trochoid surface of the rotor housing.
  • the apex seal 10 is an elongated member and is formed from a hard material such as graphite.
  • the material of the seal 10 is characterized by its low modulus of elasticity and its high strength. It fits within a groove 12 that parallels the axis of rotation of a rotary piston or rotor 14.
  • the rotor I4 is of conventional triangular configuration and is rotatably supported on an eccentric portion ofan eccentric shaft situated within a housing I6.
  • the housing 16 has .a trochoid bearing surface 18. A pair of side walls cooperate with the trochoid surface 18 to define a cavity within which the rotor 14 rotates.
  • the apex seal 10 has a width that is only slightly less than the width of the groove 12. It protrudes radially from the open side of the groove 12 by an amount that is approximately equal to the clearance between the apex portion of the rotor 14 and the trochoid surface.
  • the apex seal 10 is of an elongated construction and has a series of overlapping slots or cuts formed along its two lateral sides.
  • a series of slots 20, 22 and 24 are cut into the seal 10 from the right-hand side.
  • a second series of slots 26, 28 and 30 are cutv into the left side of the seal. The several slots are cut sufficiently deep so that the slots 20, 22 and 24 are in overlapping relationship with the slots 26, 28 and 30.
  • the upper edge of the seal 10 is provided with a groove 32 in which a friction reducing plastic piece 34 is embedded.
  • the embedment 34 comprises a friction smearable fluxing agent in the form ofpolyarylsulfone. This material engages the trochoid surface 18 and co operates with the surface 18 during rotation of the rotor 14 in the manner described in my aforementioned United States patent application entitled RUBBING SEAL SYSTEM FOR A ROTARY COMBUSTION ENGINE.
  • the base of the seal 10 is sealed with respect to the depth of the groove 12 by means of an expanded silicone sponge material 36. This material is also described in my recent patent application.
  • each corner seal is of cylindrical construction and tits within a cylindrical recess in the end face of the rotor.
  • the corner seals are displaceable only in an axial direction.
  • a longitudinal hole 38 may be provided in the base portion of the seal 10 and a pin 40 extended through the hole 38. The ends of the pin 40 engage the corner seals and provide a means for preventing radial displacement of the seal 10 with respect to the rotor 14.
  • Other means may also be provided for securing the base of the seal 10 in the groove 12.
  • the seal base may be cemented in position by using a sealing material 36 which has adhesive qualities in addition to sealing qualitied.
  • the base of the apex seal 10 is retained in the groove 12 by means of the material 36 and additionally by means of the pin 40, if desired.
  • the seal 10 is formed of rigid graphite, it has limited flexibility due to the overlapping side slots 20 to 30. This construction provides a seal that is flexible both from side to side as well as having adequate radial resiliency.
  • the apex seal 10 is constructed to flex from side to side in response to prevailing pressures in the chambers of the rotary engine. As seen in FIG. 2, the seal 10 divides a portion of the interior of the housing 16 into combustion chambers A and B. Referring to FIG. 4, when the pressure in chamber A exceeds the pressure in chamber B, seal 10 will flex to the right as shown. The seal 10 is thereby placed in sealed engagement with one ofthe outer edges of the apex groove 12 as indicated by reference letter X. The flexing of the seal 10 also places it in sealed engagement with the opposite wall of the groove 12. In addition, the material 36 seals the base of the apex seal 10 with respect to the depth of the groove 12.
  • a gas seal having excellent properties for isolating chamber A from chamber B.
  • the seal may be manufactured from a rigid graphite material and is characterized by its low cost.
  • each of the slots 20 through 30 has a width A.
  • the slots overlap and are, therefore, separated by material which has a thickness B.
  • the inner extremity of each slot is spaced from the opposite wall of the seal by a dimension C.
  • the width ofthe slots (dimension A) should be less than the thickness of the material which separates the slots (dimension B).
  • the width of the slots (dimension A) should be equal to or less than US ofthe dimension between the inner end of each slot and the opposite wall of the seal (dimension C).
  • a graphite apex seal having slots that are formed within these dimensional limits will have the necessary flexibility properties to permit lateral displacement to the right and to the left as shown in FIGS. 4 and 5, re-
  • the apex seal will have the desired amount of the radial resiliency.
  • the apex seal 10 ofthis invention consists of a graphite block slotted along the lateral sides as shown.
  • a graphite material having a low elastic modulus and high strength is suitable for this application.
  • the rubbing surface of the seal 10 is grooved and filled with a filled polymer coating to provide low friction.
  • the apex seal 10 is held against radial displacement by any suitable means such as the pin 40 extending between two corner seals. Conventionally, corner seals have a fixed position in the radial direction and are permitted axial motion only. The pin 40 restrains the base of the apex seal 10 against radial movement thus neutralizing the centrifu gal force component of the seal produced by motion of the rotor.
  • a rotary combustion engine comprising a housing having a trochoid surface
  • an apex seal disposed in said groove and having one edge engaging said trochoid surface
  • said seal being formed of a material having a low modulus of elasticity
  • said seal having a plurality of longitudinally'arranged slots formed along each of its lateral sides
  • said slots of one lateral side being arranged in overlapping relationship with respect to said slots of the other lateral side
  • said slots being constructed to increase the effective elasticity of said seal
  • said retaining means being constructed to hold the base of said seal against radial displacement with respect to said rotor
  • said seal being laterally flexible within said groove and radial-1y resilient.
  • An apex seal for a rotary combustion engine according to claim 1 and including:
  • said slot having a greater depth than one-half the width of said seal measured from said one lateral side to the other lateral side.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Sealing Devices (AREA)
  • Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
US400282A 1973-09-24 1973-09-24 Seal for rotary combustion engine Expired - Lifetime US3873249A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US400282A US3873249A (en) 1973-09-24 1973-09-24 Seal for rotary combustion engine
GB3824174A GB1453177A (en) 1973-09-24 1974-09-02 Apex seal for a rotary engine
CA208,609A CA1029666A (en) 1973-09-24 1974-09-06 Seal for rotary combustion engine
DE19742444278 DE2444278A1 (de) 1973-09-24 1974-09-17 Scheiteldichtleiste fuer rotationskolben-verbrennungsmotoren
JP10894474A JPS554928B2 (it) 1973-09-24 1974-09-24

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US400282A US3873249A (en) 1973-09-24 1973-09-24 Seal for rotary combustion engine

Publications (1)

Publication Number Publication Date
US3873249A true US3873249A (en) 1975-03-25

Family

ID=23582966

Family Applications (1)

Application Number Title Priority Date Filing Date
US400282A Expired - Lifetime US3873249A (en) 1973-09-24 1973-09-24 Seal for rotary combustion engine

Country Status (5)

Country Link
US (1) US3873249A (it)
JP (1) JPS554928B2 (it)
CA (1) CA1029666A (it)
DE (1) DE2444278A1 (it)
GB (1) GB1453177A (it)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4144003A (en) * 1977-11-23 1979-03-13 Curtiss-Wright Corporation Bar type seal for rotary mechanism
US4201526A (en) * 1976-12-06 1980-05-06 Eugenius Brochstein Pivoted blade between rotor and stator having arcuate sections
EP0656462A1 (de) * 1993-11-19 1995-06-07 Firma Carl Freudenberg Dichtungsanordnung
US20100150762A1 (en) * 2006-12-02 2010-06-17 Eggert Guenther System for sealing the piston of rotary piston machines
WO2013087068A3 (de) * 2011-12-14 2014-04-10 Ixetic Bad Homburg Gmbh Dichteinrichtung
US8967988B2 (en) 2011-07-28 2015-03-03 Pratt & Whitney Canada Corp. Apex and face seals with rotary internal combustion engine

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5825788U (ja) * 1981-08-17 1983-02-18 三菱自動車工業株式会社 トラツクの車体構造
WO1989012160A1 (fr) * 1988-06-08 1989-12-14 Bando Kiko Co., Ltd. Moteur rotatif
DE102005017435A1 (de) * 2005-04-15 2006-10-19 Schaeffler Kg Vorrichtung zur variablen Einstellung der Steuerzeiten von Gaswechselventilen einer Brennkraftmaschine
DE102005017436A1 (de) * 2005-04-15 2006-10-19 Schaeffler Kg Vorrichtung zur Nockenwellenverstellung einer Brennkraftmaschine

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3113526A (en) * 1961-04-13 1963-12-10 Nsu Motorenwerke Ag Slit apex seals
US3194488A (en) * 1962-09-10 1965-07-13 Goetzewerke Sealing bar for rotating piston engines
US3245387A (en) * 1962-08-25 1966-04-12 Nsu Motorenwerke Ag Sealing structures
US3664778A (en) * 1967-06-07 1972-05-23 Svenska Rotor Maskiner Ab Rotary internal combustion engine and sealing means therefor
US3756754A (en) * 1970-10-24 1973-09-04 Nippon Piston Ring Co Ltd Apex seal for rotary piston engine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3113526A (en) * 1961-04-13 1963-12-10 Nsu Motorenwerke Ag Slit apex seals
US3245387A (en) * 1962-08-25 1966-04-12 Nsu Motorenwerke Ag Sealing structures
US3194488A (en) * 1962-09-10 1965-07-13 Goetzewerke Sealing bar for rotating piston engines
US3664778A (en) * 1967-06-07 1972-05-23 Svenska Rotor Maskiner Ab Rotary internal combustion engine and sealing means therefor
US3756754A (en) * 1970-10-24 1973-09-04 Nippon Piston Ring Co Ltd Apex seal for rotary piston engine

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201526A (en) * 1976-12-06 1980-05-06 Eugenius Brochstein Pivoted blade between rotor and stator having arcuate sections
US4144003A (en) * 1977-11-23 1979-03-13 Curtiss-Wright Corporation Bar type seal for rotary mechanism
EP0656462A1 (de) * 1993-11-19 1995-06-07 Firma Carl Freudenberg Dichtungsanordnung
US20100150762A1 (en) * 2006-12-02 2010-06-17 Eggert Guenther System for sealing the piston of rotary piston machines
US8920147B2 (en) * 2006-12-02 2014-12-30 Eggert Guenther System for sealing the piston of rotary piston machines
US8967988B2 (en) 2011-07-28 2015-03-03 Pratt & Whitney Canada Corp. Apex and face seals with rotary internal combustion engine
US9850758B2 (en) 2011-07-28 2017-12-26 Pratt & Whitney Canada Corp. Apex and face seals with rotary internal combustion engine
WO2013087068A3 (de) * 2011-12-14 2014-04-10 Ixetic Bad Homburg Gmbh Dichteinrichtung
US9534598B2 (en) 2011-12-14 2017-01-03 Magna Powertrain Bad Homburg GmbH Sealing device for a cam ring of a variable displacement pump

Also Published As

Publication number Publication date
DE2444278A1 (de) 1975-03-27
JPS554928B2 (it) 1980-02-01
JPS5059609A (it) 1975-05-23
CA1029666A (en) 1978-04-18
GB1453177A (en) 1976-10-20

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