US3712767A - Sealing arrangement for rotary combustion engine - Google Patents

Sealing arrangement for rotary combustion engine Download PDF

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Publication number
US3712767A
US3712767A US00145442A US3712767DA US3712767A US 3712767 A US3712767 A US 3712767A US 00145442 A US00145442 A US 00145442A US 3712767D A US3712767D A US 3712767DA US 3712767 A US3712767 A US 3712767A
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United States
Prior art keywords
percent
seal
parts
alloy
peripheral surface
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Expired - Lifetime
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US00145442A
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English (en)
Inventor
K Beutter
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Audi AG
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Audi AG
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Publication date
Priority claimed from DE19702027115 external-priority patent/DE2027115C3/de
Application filed by Audi AG filed Critical Audi AG
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Expired - Lifetime legal-status Critical Current

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    • 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
    • F01C19/04—Radially-movable sealings for working fluids of rigid material

Definitions

  • ABSTRACT A sealing arrangement for the apexes of the rotor of a rotary combustion engine, wherein the inner surface of the peripheral housing, the end walls, and the parts of the seal are of different graduated hardnesses, whereby the seal rapidly wears into a perfect tit and sealing engagement without danger of scoring or abrading the housing.
  • the end pieces When the engine is hot and the length of the operating chamber expands, the end pieces are forced radially outward by their spring loading, and also longitudinally outward along the inclined planes, thus maintaining sealing contact with the side walls and at least in part filling the gaps at the comers of the main seal piece. If the axial spacing between the side walls varies from place to place in the periphery of the engine, as between a hot zone and a relatively cool zone, the triangular end seal pieces are squeezed in and out as the rotor turns.
  • the disadvantage of this arrangement is that at times when the axial spacing of the side walls is minimal, because of manufacturing tolerances the corners of the main seal piece may gouge the surface of the side walls, or the delicate corners of the seal are rapidly worn off, permanently enlarging the leakage gap at the corners. At other times, when axial spacing of the side walls is greater than the length of the seal members in their optimum position, the corners of the triangular end seal pieces may gouge the peripheral housing surface, or again, their delicate comers may be rapidly worn down, so that the corner gap is again enlarged. Also, these difficulties are not due solely to manufacturing tolerances and to varying engine conditions, but in addition they may arise from uneven wear of the seal parts owing to minute variations in hardness.
  • the present invention results in optimum sealing over a long period of time, and keeps as small as possible the wear of the inner surfaces of the housing and of the seal parts.
  • the invention provides a threepiece seal assembly with a trapezoidal main part sweeping the peripheral housing, and a pair of end pieces likewise substantially trapezoidal in form, but having surfaces sweeping both a side wall and a portion of the peripheral housing, and mating with the main part along an inclined plane.
  • the inner surface of the peripheral housing is formed of a harder material than the inner faces of the side walls
  • the middle piece of the seal assembly is formed of a harder material than the end pieces.
  • FIG. 1 is an axial cross-section of an engine, showing the hard facing of the peripheral housing and an apex seal assembly in place;
  • FIG. 2 is a fragmentary cross-section showing the position of the seal parts at installation.
  • FIG. 1 shows a rotary combustion engine 1 having a peripheral housing 2 and side walls 3 and 4, which together define an internal cavity 5.
  • a generally polygonal, multi-apexed rotor 6 is rotatably mounted within the cavity on an eccentric portion 7 of a shaft 8 which transpierces the end walls.
  • the rotor 6 is provided at each apex with an axially-extending groove 9, in which is disposed an apex seal assembly 10, comprising a trapezoidal middle part 11 and two smaller trapezoidal end parts 12.
  • the positioning of the seal parts is such that the longest edge of the middle part 1 1 sweeps along the inner peripheral surface 13, while the end parts 12 have their shortest edges sweeping the peripheral surface 13 and their end edges, at to their shortest edges, sweeping the inner faces 14 of the side walls 3 and 4.
  • the middle seal part and the end parts meet along sloping edges 16 disposed at an angle to the longitudinal axis of the shaft.
  • a leaf spring 15 is disposed in the groove 9 under the seal assembly, with its ends bearing against the undersides of the end parts 12 and urging them radially outward, whereby through the wedging action of the oblique abutment surfaces 16 between the middle part and the end parts there occurs a simultaneous pressing of the middle part 11 against the inner peripheral surface 13 and of the end parts 12 against the inner. faces 14 of the side walls 3 and 4.
  • the peripheral housing 2 is provided with an inner coating layer 13 of hard material, as for instance a deposit of nickel containing a distribution of 2 to 8 percent silicon carbide particles having an average grain size of approximately 1 micron. This material is harder than the inner faces 14 of the side walls, which may be of nitrided hardened cast iron.
  • the middle part 1 l of the apex seal is harder than the end parts 12, the middle part having a Vickers hardness (l0 kilogram load) of at least 600 and preferably of more than 1,000, and the end pans having a hardness of 300 to 500.
  • the material for the middle part consists of an iron alloy containing at least 30 percent by weight of titani um carbide, and the end parts are formed of a cast iron alloy of the type used for piston rings. Nominal compositions for suitable alloy materials for the middle seal part areas follows.
  • the Vickers hardness of the alloy of Example I amounts to approximately 1,030 to 1,090, and the hardness of the alloy of Example 11 amounts to approximately 700 to 750.
  • the material of the end parts of the seal strip may be a cast iron alloy having the nominal composition given below, with a Vickers hardness of approximately 350 to 450.
  • FIG. 2 shows the method of installing the seal assembly. At installation, only the end parts 12 are pressed by the spring against the inner peripheral surface 13, with the main seal piece 11 resting between them against the slanted edges 16. The gap between the main seal piece and the surface 13, however, is much exaggerated in the drawing for clarity of illustration. Because the end parts are formed of a relatively soft material compared to the inner peripheral surface, in operation their short edges rapidly wear down to the height of the middle part 11, so that after a short run-in period the condition shown in FIG. 1 is reached, in which the middle part and the end parts bear against the peripheral surface 13 across its entire width, while the end parts continue to maintain sealing abutment against the side walls.
  • the seal assembly will continue to run true and maintain good sealing over a long period of time.
  • the hard material of the main seal piece 11 wears very slowly, and the end parts 12 being softer they will always wear to at least the same amount and thus not protrude, with the danger of abrading the housing.
  • the end parts since the end parts have only a small bearing portion against the peripheral housing, the major part of seal wear is taken up by the center piece, and the end parts will not wear to a lower level and leave a gap.
  • a rotary internal combustion engine having a peripheral housing and a pair of side housings defining an internal cavity and a rotor rotatably mounted within the cavity, the rotor having a plurality of apex portions with a sealing arrangement positioned in a slot at each apex portion to sweep the inner surface of the peripheral housing and the inner faces of the side housings in sealing relationship, wherein the improvement comprises:
  • the inner peripheral surface being formed of a harder material than the inner faces of the side housings;
  • each sealing arrangement comprising a middle part and two end parts; the middle seal part being generally trapezoidal and having a longside disposed radially outwardly and sweeping t e inner peripheral surface, a
  • shorter side parallel with the long side and disposed radially inwardly, and two short ends slanting from the long side to the shorter side;
  • the two end parts each being generally trapezoidal and having a short side disposed radially outwardly and sweeping the inner peripheral surface, a longer side parallel with the shorter side and disposed radially inwardly, one end perpendicular to the short side and to the long side and sweeping the adjacent side housing, and an opposite end slanting from the short side to the longer side and juxtaposed in mating relationship to the slanting end of the middle seal part in such a manner that the sealing assembly of the three seal parts has a generally rectangular outline;
  • the middle seal part being formed of a harder material than the end seal parts but less hard than the inner peripheral surface of the housing;
  • the end seal parts being urged resiliently outwardly and exerting a wedging action outwardly against the middle seal part to maintain the radially outward edges of the three seal parts in sealing contactwith the inner peripheral surface with seal wear thereagainst being preferentially absorbed by the end seal parts.
  • the inner peripheral surface is formed of a layer of nickel having hard particles incorporated therein
  • the middle seal part consists of a material having a Vickers hardness of at least 600
  • the seal end parts consist of a material having a Vickers hardness of at least 300.
  • nickel layer has incorporated therein from 2 to 8 percent of silicon carbide particles having an average particle size of approximately 1 micron.
  • end seal parts are formed of an alloy consisting of 3.4 to 3.8 percent carbon; 2.5 to 3.2 percent silicon; 0.8 to 1.3 percent molybdenum; less than 1 percent each of manganese, chromium, vanadium, copper, and nickel; and the balance iron, the alloy having a Vickers hardness of at least 350.
  • the middle seal part is formed of an alloy having the nominal composition of 34.5 percent titanium carbide, 0.2 percent nickel, 0.55 percent carbon, 2 percent molybdenum, 6.5 percent chromium, and the balance iron, the alloy having a Vickers hardness over 1,000.
  • the middle seal part is formed of an alloy having the nominal composition of 33 percent titanium carbide, 15 percent nickel, 5 percent molybdenum, 9 percent cobalt, 0.7 percent titanium, 0.7 percent aluminum, 0.5 percent copper, and the balance iron, the alloy having a l l 4 4' I

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Sealing Devices (AREA)
US00145442A 1970-06-03 1971-05-20 Sealing arrangement for rotary combustion engine Expired - Lifetime US3712767A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702027115 DE2027115C3 (de) 1970-06-03 Rotationskolben-Brennkraftmaschine

Publications (1)

Publication Number Publication Date
US3712767A true US3712767A (en) 1973-01-23

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ID=5772842

Family Applications (1)

Application Number Title Priority Date Filing Date
US00145442A Expired - Lifetime US3712767A (en) 1970-06-03 1971-05-20 Sealing arrangement for rotary combustion engine

Country Status (5)

Country Link
US (1) US3712767A (OSRAM)
JP (1) JPS548802B1 (OSRAM)
CA (1) CA939272A (OSRAM)
FR (1) FR2095816A5 (OSRAM)
GB (1) GB1334605A (OSRAM)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3857656A (en) * 1973-05-17 1974-12-31 Nissan Motor Apex seal for a rotary internal combustion engine
US3909310A (en) * 1973-08-24 1975-09-30 Ford Motor Co Apex seal design
US3915600A (en) * 1973-10-09 1975-10-28 Daimler Benz Ag Radial sealing bar for a rotary piston internal combustion engine
US3973882A (en) * 1975-03-17 1976-08-10 General Motors Corporation Rotary combustion engine apex seal arrangement
US4025366A (en) * 1973-01-17 1977-05-24 Audi Nsu Auto Union Aktiengesellschaft Method of making rotary piston engine cast iron interior seals by quench hardening
US4074956A (en) * 1975-11-29 1978-02-21 Riken Piston Ring Kogyo Kabushiki Kaisha Sulphur and nitrogen treated iron based rotor for rotary piston engine
US4094618A (en) * 1976-03-31 1978-06-13 Toyo Kogyo Co., Ltd. Rotary piston engines
US4225294A (en) * 1977-06-10 1980-09-30 Toyo Kogyo Co., Ltd. Oil seal means for rotary piston engines including a nitrided and ground surface
US4640125A (en) * 1985-04-08 1987-02-03 Lake Charles Instruments, Inc. Rotary metering device useful with abrasive fluids
US4744738A (en) * 1984-10-08 1988-05-17 Shimadzu Corporation Gear pump or motor with hard layer in interior casing surface
US5165870A (en) * 1990-05-30 1992-11-24 Kabushiki Kaisha Toshiba Refrigerant compressor
US5785510A (en) * 1994-09-01 1998-07-28 Fluid Management Limited Partnership Gear pump having members with different hardnesses
US6250900B1 (en) * 1999-11-15 2001-06-26 Sauer-Danfoss Inc. Positive displacement hydraulic unit with near-zero side clearance

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR9007710A (pt) * 1989-10-04 1992-07-21 Archimedes Associates Inc Maquina de pistao rotativo

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263912A (en) * 1963-07-23 1966-08-02 Goetzewerke Radial seal
US3281064A (en) * 1963-12-18 1966-10-25 Daimler Benz Ag Seal construction
US3318515A (en) * 1965-06-07 1967-05-09 Curtiss Wright Corp Wear resistant construction for rotary mechanisms
US3394877A (en) * 1966-12-15 1968-07-30 Sachwenring Automobilwerke Zwi Rotary piston engine
US3554677A (en) * 1968-05-14 1971-01-12 Krebsoege Gmbh Sintermetall Rotary piston engine
US3608535A (en) * 1968-11-06 1971-09-28 Outboard Marine Corp Sealant for wear-resistant coating

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263912A (en) * 1963-07-23 1966-08-02 Goetzewerke Radial seal
US3281064A (en) * 1963-12-18 1966-10-25 Daimler Benz Ag Seal construction
US3318515A (en) * 1965-06-07 1967-05-09 Curtiss Wright Corp Wear resistant construction for rotary mechanisms
US3394877A (en) * 1966-12-15 1968-07-30 Sachwenring Automobilwerke Zwi Rotary piston engine
US3554677A (en) * 1968-05-14 1971-01-12 Krebsoege Gmbh Sintermetall Rotary piston engine
US3608535A (en) * 1968-11-06 1971-09-28 Outboard Marine Corp Sealant for wear-resistant coating

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025366A (en) * 1973-01-17 1977-05-24 Audi Nsu Auto Union Aktiengesellschaft Method of making rotary piston engine cast iron interior seals by quench hardening
US3857656A (en) * 1973-05-17 1974-12-31 Nissan Motor Apex seal for a rotary internal combustion engine
US3909310A (en) * 1973-08-24 1975-09-30 Ford Motor Co Apex seal design
US3915600A (en) * 1973-10-09 1975-10-28 Daimler Benz Ag Radial sealing bar for a rotary piston internal combustion engine
US3973882A (en) * 1975-03-17 1976-08-10 General Motors Corporation Rotary combustion engine apex seal arrangement
US4074956A (en) * 1975-11-29 1978-02-21 Riken Piston Ring Kogyo Kabushiki Kaisha Sulphur and nitrogen treated iron based rotor for rotary piston engine
US4094618A (en) * 1976-03-31 1978-06-13 Toyo Kogyo Co., Ltd. Rotary piston engines
US4225294A (en) * 1977-06-10 1980-09-30 Toyo Kogyo Co., Ltd. Oil seal means for rotary piston engines including a nitrided and ground surface
US4744738A (en) * 1984-10-08 1988-05-17 Shimadzu Corporation Gear pump or motor with hard layer in interior casing surface
US4640125A (en) * 1985-04-08 1987-02-03 Lake Charles Instruments, Inc. Rotary metering device useful with abrasive fluids
US5165870A (en) * 1990-05-30 1992-11-24 Kabushiki Kaisha Toshiba Refrigerant compressor
US5785510A (en) * 1994-09-01 1998-07-28 Fluid Management Limited Partnership Gear pump having members with different hardnesses
US6250900B1 (en) * 1999-11-15 2001-06-26 Sauer-Danfoss Inc. Positive displacement hydraulic unit with near-zero side clearance

Also Published As

Publication number Publication date
DE2027115A1 (de) 1971-12-09
DE2027115B2 (de) 1976-04-22
CA939272A (en) 1974-01-01
FR2095816A5 (OSRAM) 1972-02-11
JPS548802B1 (OSRAM) 1979-04-19
GB1334605A (en) 1973-10-24

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