US3782869A - Oil seal construction for rotary engines - Google Patents

Oil seal construction for rotary engines Download PDF

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Publication number
US3782869A
US3782869A US00281765A US3782869DA US3782869A US 3782869 A US3782869 A US 3782869A US 00281765 A US00281765 A US 00281765A US 3782869D A US3782869D A US 3782869DA US 3782869 A US3782869 A US 3782869A
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US
United States
Prior art keywords
rotor
ring
seal
seal ring
side wall
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
US00281765A
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English (en)
Inventor
J Steinwart
A Bauder
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.)
Audi AG
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Audi AG
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Filing date
Publication date
Priority claimed from DE19712144497 external-priority patent/DE2144497C3/de
Application filed by Audi AG filed Critical Audi AG
Application granted granted Critical
Publication of US3782869A publication Critical patent/US3782869A/en
Anticipated expiration legal-status Critical
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
    • F01C19/10—Sealings for working fluids between radially and axially movable parts

Definitions

  • This invention relates to rotary internal combustion engines, and more particularly to engines of the trochoidal type.
  • Such an engine comprises a housing having a peripheral wall with a generally trochoidal multilobed inner surface and a pair of parallel side walls, the housing having inlet and outlet ports and defining an engine cavity, a shaft transpiercing the side walls and having an eccentric portion disposed within the cavity, a multiapexed rotor of generally polygonal profile rotatably mounted on the eccentric with its apexes sweeping the inner peripheral surface, and appropriate sealing elements at the apexes and sides of the rotor.
  • the rotor commonly bears in an annular groove on each side at least one oil seal ring surrounding the eccentric and sealing against the adjacent side wall to prevent leakage of oil from the bearings into the working chambers.
  • the seal ring shown there however, is too rigid to have sufficient resilience, either requiring a very delicate fit to assure contact with both the side wall and the rotor, which causes increased friction and perhaps binding when the parts are hot, or else elastomeric backings to provide resilience.
  • the rotor has no provision for cooling.
  • This invention solves the problems of the prior art by providing an oil seal which, instead of being washed by hot oil after discharge from the rotor, is continuously cooled by the rotor internal coolant before discharge from the interior of the rotor, thus maintaining the seals cooler and improving the durability of the sealing elements. Further, the invention provides a seal assembly such that it can be applied to the rotor, thus eliminating the previous annular grooves in the rotor side walls and allowing its central opening to be made very large, almost out to the rotor periphery. This provides greater access to the interior of the rotor, making it possible to form the casting cores, which must extend through the central openings, much stronger and more stable, re ducing the expense of fabrication.
  • a support ring for the seal assembly which can be positioned within the large central opening of the rotor side wall, coaxially therewith, the support ring being mounted on the rotor hub surrounding the eccentric.
  • the support ring is so formed as to provide communication between the seals and the rotor cavity, allowing the inner surfaces of the seals to be washed by the internal coolant within the cavity.
  • a single oil sealing ring may be used, or a plurality of such rings concentrically disposed, and resilient flexible sealing elements are pro vided between the circumference of the outermost ring and the cylindrical wall of the rotor opening, and also between seal rings if more than one are used.
  • the ring gear mounted on the rotor may also serve as the support ring for the oil seal.
  • a further object is to provide such arotor having large central openings through the rotor side walls, in which openings oil sealing assemblies can be installed.
  • FIG. I is a transverse cross-section of a rotary internal combustion engine according to the invention, taken along line 1-1 of FIG. 2;
  • FIG. 2 is a cross-section along line 22 of FIG. 1 on an enlarged scale
  • FIG. 3 is a fragmentary section on a still larger scale of the portion of FIG. 2 within the circle A.
  • FIGS. 1 and 2 there is shown a rotary internal combustion engine of trochoidal design, having a housing comprising a peripheral wall 1 having a two-lobed inner surface 2, and side walls 3 and 4, which together define an engine cavity 5.
  • a shaft 6 transpierces the side walls, being rotatably mounted therein on bearings 7, and has an eccentric portion 8 disposed within the engine cavity.
  • a generally triangular rotor 9 is rotatably mounted on the eccentric on a bearing 10. The rotational speed of the rotor 9 is in a ratio of 1 3 relative to the rotational speed of the shaft 6. This ratio is maintained by indexing gears comprising a ring gear 11 fastened to the rotor and in mesh with a pinion l2 borne by the side wall 3.
  • a radial apex seal 13 which apex seals sweep along the inner surface 2 of the peripheral housing, whereby there are formed three variable-volume combustion chambers 14.
  • an inlet channel 15 for fresh gas a spark plug schematically indicated at 16, and an exhaust channel 17 for burned gases.
  • the inlet and exhaust channels may be provided in one or both the side walls, however.
  • the rotor 9 has interconnected internal cavities 18 through which flows a cooling fluid.
  • This coolant is supplied through an axial bore 19 in shaft 6, and is transmitted by means of transverse bores 20 to the shaft bearings 7 and through a transverse bore 21 in the eccentric to the rotor bearing 10.
  • the cooling and lubricating medium emerges from the ends of bearing 10 and is thrown by centrifugal force into the individual cavities 18 in the rotor.
  • Each rotor side wall 22 has a central circular opening 23 through which the cooling fluid emerges after it has flowed through cavities 18. The coolant is then conducted away through apertures 3a and 4a in the side walls 3 and 4 respectively.
  • the rotor is provided at each side with an annular seal assembly 24.
  • the seal assembly 24 shown by way of example has two seal rings 25 and 26 of L-shaped cross-section, concentrically disposed and installed in the opening 23 of each side wall.
  • the seal rings 25 and 26 are axially displaceable, and are urged by a common annular wave spring 27 against the inner surface of the adjacent side wall.
  • the annular wave spring 27 is supported and backed up by a ring 28, which is fastened to the rotor hub by screws 29, the screws passing entirely through the hub and being threaded into a similar ring on the other side of the rotor.
  • the ring supporting the seals on the opposite side is the ring gear 11.
  • the seal element 30 has a C- shaped cross-section, and may be formed, for example, of a thin-walled annular metal tube, slit along one side. Removing some of the metal along the slit, or opening it up, leaves a springy annular tube which through its inherent stress bears resiliently against the cylindrical wall of the opening 23 and against the axially extending leg of seal ring 25.
  • a similar annular resilient seal elcment 3] is positioned between the two seal rings 25 and 26.
  • the annular seal elements 30 and 31 may, if desired, be coated on the exterior with a suitable substance, for example polytetrafluoroethylene.
  • the supporting ring 28 defines, with the rear side of seal rings 25 and 26, an annular space 32 which is in communication with the internal cavities 18 of the rotor.
  • the gap 32 has coolant continuously flowing through it and good cooling is obtained for the seal rings and for the flexible sealing elements 30 and 31. Consequently, instead of using annular tubing as shown, the seal elements 30 and 31 may be made of rubber or a similar elastomer.
  • the L-shaped crosssection of rings 25 and 26, with the seal elements 30 and 31 surrounding the axially extending leg allows the coolant to arrive unhindered at elements 30 and 31, and the axial legs of the seal rings.
  • the radially extending legs of rings 25 and 26 maintain the seal rings in their concentric position within the rotor opening 23.
  • the seal rings may have flat faces against the side walls 3 and 4, but for better sealing the sealing faces preferably have a slight taper as shown in FIG. 3, leaving a scraping edge at the inner circumference of each ring.
  • the inner circumference of the rings may also be coated with a harder material 37 than the main body of the ring, in order to provide a scraping edge which does not readily wear.
  • the seal-supporting ring 28 comprises generally a hub portion radially inside the seal rings and extending toward the engine side wall, and a flange portion extending radially outwardly from the hub portion on the side positioned toward the rotor interior.
  • the flange portion has an annular groove 33 on the side facing the seal rings, in which groove is positioned an annular wave spring 27 which bears against the axially extending legs of both seal rings, urging them against the engine side wall.
  • the flange portion of supporting ring 28 has at its periphery an annular web 34 extending toward the seal assembly, which web prevents sealing element 30 from moving toward the interior of the rotor.
  • Web 34 has a plurality of cuts or slots 35 therethrough to maintain the gap 32 in communication with the rotor cavities 18. Sealing element 31 is maintained axially in position by the undulated wave spring 27, and coolant reaches element 31 through the undulations of the spring.
  • the hub portion of supporting ring 28 which is disposed radially inside the seal rings 25 and 26 is extended toward the housing side wall 4 slightly beyond the plane of the rotor side wall, thus providing a running surface against the wall for axial piloting of the rotor.
  • the seal assembly shown in FIG. 3 is disposed on the side of the rotor opposite the indexing gears 11 and 12. However, the seal assembly on the gear side is identical with that of FIG. 3 except that the support ring comprises the ring gear 11, and has internal gear teeth on its inner circumference in engagement with the external teeth of pinion gear 12 borne by the housing side wall 3. Ring gear 11 is mounted on the rotor 9 by the same screws which hold supporting ring 28, which screws pass through the rotor hub.
  • Positioning the seal assemblies 24 within the central openings 23 in the rotor side walls 22 not only has the advantage of enabling the seals to be continuously cooled from the rotor interior, but has the further advantage that openings 23 can be made quite large.
  • the large diameter of these openings makes it possible to form the cores which serve in the fabrication of the rotor much more substantially, stronger and more stable than formerly. Because of the small radial extent of the side walls 22 of the rotor, the weight of the rotor is also decreased.
  • the invention renders it possible to build rotary engines of the trochoidal type with a greater traverse angle than heretofore, because the space previously needed for the seal grooves in engines of the prior art is saved.
  • a rotary internal combustion engine having a housing comprising a peripheral wall having a multilobed inner surface and a pair of end walls defining an engine cavity, a shaft transpiercing the end walls and having an eccentric portion within the engine cavity, a multiapexed rotor rotatably mounted on the eccentric, the rotor having internal cavities through which a cooling medium flows and having side walls each having a central circular opening therein, wherein the improvement comprises:
  • a sealing assembly disposed at each side of the rotor and having at least one axially movable seal ring disposed in the rotor side wall opening on its associated side;
  • a resilient flexible annular sealing member comprising a thin-walled split tube disposed between the cylindrical wall of the rotor opening and the outer circumference of the seal ring in sealing relation to the seal ring and the cylindrical wall;
  • a supporting ring mounted on the rotor axially inwardly of the seal ring, and spring means disposed between the supporting ring and the seal ring and urging the seal ring against the adjacent housing side wall; and the supporting ring defining with the axially inward side of the seal ring an annular space in communication with the rotor internal cavities whereby the rotor cooling medium flows through the annular space to cool the sealing assembly, the axially inward side of the flexible annular sealing member being exposed to the cooling medium and washed thereby.
  • the supporting ring has in the side facing the seal ring an annular channel in which the spring means is disposed, the supporting ring having at its outer periphery an annular web extending toward the seal ring and defining the outer circumference of the annular spring channel, the web having a plurality of generally radial slots therethrough providing communication between the rotor internal cavities and the annular space between the supporting ring and the seal ring.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Sealing Devices (AREA)
US00281765A 1971-09-06 1972-08-18 Oil seal construction for rotary engines Expired - Lifetime US3782869A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712144497 DE2144497C3 (de) 1971-09-06 Rotationskolben-Brennkraftmaschine

Publications (1)

Publication Number Publication Date
US3782869A true US3782869A (en) 1974-01-01

Family

ID=5818754

Family Applications (1)

Application Number Title Priority Date Filing Date
US00281765A Expired - Lifetime US3782869A (en) 1971-09-06 1972-08-18 Oil seal construction for rotary engines

Country Status (5)

Country Link
US (1) US3782869A (enFirst)
JP (1) JPS5440688B2 (enFirst)
FR (1) FR2152126A5 (enFirst)
GB (1) GB1342215A (enFirst)
IT (1) IT964019B (enFirst)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3869229A (en) * 1973-03-26 1975-03-04 Toyo Kogyo Co Sealing device for use in rotary piston engine
US3884602A (en) * 1974-01-11 1975-05-20 Gen Motors Corp Rotary engine oil seal assembly
US3909166A (en) * 1973-09-25 1975-09-30 Toyota Motor Co Ltd Oil seal means of a rotary piston engine
US3918858A (en) * 1973-06-02 1975-11-11 Toyota Motor Co Ltd Oil seal arrangement for a rotary engine
USRE28714E (en) * 1972-07-14 1976-02-17 Audi Nsu Auto Union Aktiengesellschaft Internal seal for rotary piston combustion engine
US4090824A (en) * 1976-04-09 1978-05-23 Audi Nsu Auto Union Aktiengesellschaft Rotary piston engine piston having an internal seal
US4218200A (en) * 1977-06-30 1980-08-19 Toyo Kogyo Co., Ltd. Rotor cooling means for rotary piston engines
US9896934B2 (en) 2013-12-17 2018-02-20 Pratt & Whitney Canada Corp. Rotary engine with rotor land
CN114941568A (zh) * 2022-03-28 2022-08-26 洛阳北方企业集团有限公司 新型航空转子发动机密封结构
GB2618556A (en) * 2022-05-10 2023-11-15 Compound Rotary Engines Ltd Rotary piston internal combustion engines
US12435661B1 (en) * 2024-04-08 2025-10-07 Pratt & Whitney Canada Corp. Rotary engine with seal having shield and elastomeric member

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5070707A (enFirst) * 1973-10-29 1975-06-12
JP5817986B2 (ja) * 2011-09-29 2015-11-18 マツダ株式会社 ロータリピストンエンジン
CN106194410A (zh) * 2016-08-22 2016-12-07 占舒婷 一种热能利用的滚子发动机

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1333377A (fr) * 1961-09-14 1963-07-26 Goetzewerke Segment racleur pour moteur à explosion
US3400939A (en) * 1966-01-03 1968-09-10 Curtiss Wright Corp Oil seal construction for rotary engines
GB1167078A (en) * 1966-09-10 1969-10-15 Toyo Kogyo Kabushiki Kaisha Seal Construction for Rotary Piston Internal Combustion Engines.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1333377A (fr) * 1961-09-14 1963-07-26 Goetzewerke Segment racleur pour moteur à explosion
US3400939A (en) * 1966-01-03 1968-09-10 Curtiss Wright Corp Oil seal construction for rotary engines
GB1167078A (en) * 1966-09-10 1969-10-15 Toyo Kogyo Kabushiki Kaisha Seal Construction for Rotary Piston Internal Combustion Engines.

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE28714E (en) * 1972-07-14 1976-02-17 Audi Nsu Auto Union Aktiengesellschaft Internal seal for rotary piston combustion engine
US3869229A (en) * 1973-03-26 1975-03-04 Toyo Kogyo Co Sealing device for use in rotary piston engine
US3918858A (en) * 1973-06-02 1975-11-11 Toyota Motor Co Ltd Oil seal arrangement for a rotary engine
US3909166A (en) * 1973-09-25 1975-09-30 Toyota Motor Co Ltd Oil seal means of a rotary piston engine
US3884602A (en) * 1974-01-11 1975-05-20 Gen Motors Corp Rotary engine oil seal assembly
US4090824A (en) * 1976-04-09 1978-05-23 Audi Nsu Auto Union Aktiengesellschaft Rotary piston engine piston having an internal seal
US4218200A (en) * 1977-06-30 1980-08-19 Toyo Kogyo Co., Ltd. Rotor cooling means for rotary piston engines
US9896934B2 (en) 2013-12-17 2018-02-20 Pratt & Whitney Canada Corp. Rotary engine with rotor land
CN114941568A (zh) * 2022-03-28 2022-08-26 洛阳北方企业集团有限公司 新型航空转子发动机密封结构
GB2618556A (en) * 2022-05-10 2023-11-15 Compound Rotary Engines Ltd Rotary piston internal combustion engines
GB2618556B (en) * 2022-05-10 2024-09-25 Compound Rotary Engines Ltd Rotary piston internal combustion engines
US12435661B1 (en) * 2024-04-08 2025-10-07 Pratt & Whitney Canada Corp. Rotary engine with seal having shield and elastomeric member
US20250314196A1 (en) * 2024-04-08 2025-10-09 Pratt & Whitney Canada Corp. Rotary engine with seal having shield and elastomeric member

Also Published As

Publication number Publication date
DE2144497B2 (de) 1977-02-03
IT964019B (it) 1974-01-21
JPS5440688B2 (enFirst) 1979-12-05
FR2152126A5 (enFirst) 1973-04-20
JPS4872505A (enFirst) 1973-09-29
GB1342215A (en) 1974-01-03
DE2144497A1 (de) 1973-03-22

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