US3658451A - Apex seal for rotary piston engine - Google Patents

Apex seal for rotary piston engine Download PDF

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Publication number
US3658451A
US3658451A US71752A US3658451DA US3658451A US 3658451 A US3658451 A US 3658451A US 71752 A US71752 A US 71752A US 3658451D A US3658451D A US 3658451DA US 3658451 A US3658451 A US 3658451A
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US
United States
Prior art keywords
apex seal
apex
cast iron
seal
blank
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
US71752A
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English (en)
Inventor
Nobuyasu Gomada
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.)
Mazda Motor Corp
Yoshiwa Kogyo KK
Original Assignee
Yoshiwa Kogyo KK
Toyo Kogyo Co 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
Priority claimed from JP7291369A external-priority patent/JPS4825289B1/ja
Priority claimed from JP7291269A external-priority patent/JPS4825290B1/ja
Application filed by Yoshiwa Kogyo KK, Toyo Kogyo Co Ltd filed Critical Yoshiwa Kogyo KK
Application granted granted Critical
Publication of US3658451A publication Critical patent/US3658451A/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • 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
    • F01C19/005—Structure and composition of sealing elements such as sealing strips, sealing rings and the like; Coating of these elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0436—Iron
    • F05C2201/0439—Cast iron
    • F05C2201/0442—Spheroidal graphite cast iron, e.g. nodular iron, ductile iron

Definitions

  • ABSTRACT An apex seal for a rotary piston engine, the apex seal being 30 Foreign Appmaflon p m made of cast iron and having an elongated shape, a roundish sliding surface, the upper portion (including the sliding sur- P 1959 Japan 72912 face)'with a chilled structure containing a large proportion of Sept. 13, Japan .T tit d th lower p ti t l t thi d f th 1 height of the seal and with no chilled structure; and a method [52] U.S.Cl.
  • This invention relates to a cast iron made apex seal for rotary pistonengine. More particularly, it relates to an apex seal whose surface has been treated to form a hardened layer of chilled structure containing a large proportion of cementite and which is in sliding contact with the inner surface of a casing that houses the seal, and a method of producing the same.
  • the apex seal for a rotary piston engine is fitted at the apex of the rotary piston and is adapted to make a planetary motion with the piston while being pressed against the inner surface of the casing by the combined action of elastic force of springs disposed behind the apex seal, gas pressure in the operating chamber and centrifugal force produced by rotation of the piston.
  • the apex seal used for this purpose must be one which has excellent mechanical properties as well as high wear and heat resistances and which also does not produce an excessive wear of the inner surface of the casing and wavy abnormal abrasion, that is, so-called chatter marks.
  • chatter marks that depending upon what quality the apex seal has, it will exert a serious influence on the performance and durability of the engine and cannot, therefore, be selected simply from the standpoint of wear resistance unlike the ordinary mechanical parts.
  • the present inventors have made extensive studies on the material of apex seal and have found that the most excellent apex seal, which does not produce any chatter mark on the inner surface of the casing and satisfies the various requirements for an apex seal,.can be produced by making a seal from cast-iron and treating the seal to form a hardened layer containing a large amount of cementite, or so-called chilled structure, in the upper part thereof including its sliding surface.
  • This hardened layer of cementite popularly called as structure, is a form of ledeburite of cementite (Fe c) or a mixture form of ledeburite and pro-eutlctic cementite.
  • mottled cast iron is always present below a chilled portion, it is also next to impsible to cut out an apex seal which is chilled ex exclusively at the sliding surface from any portion of the block. For these reasons, it has been considered technically unattainable to obtain a cast iron made apex seal having a chilled structure exclusively at its sliding surface,.and hence the apex seal such as proposed in the present invention has never been thought of in the art.
  • a process for producing a desired apex seal comprising the steps of first preparing an elongated cast iron made blank material having a width equal to or slightly larger than that of the final product apex seal, then subjecting the top surface portion of said blank material to application of electron beam, arc, laser light or plasma to cause rapid melting of the material, then rapidly cooling the molten part by chilling effect of the non-molten part, and finally giving final working thereto with or without previous stress-relieving heat treatment to thereby form a hardened layer of chilled structure containing a large amount of cementite at the sliding surface of the apex seal which surface is slidingly contacted with the inner surface of the casing.
  • the apex seal obtained according to the present invention is formed with a hardened layer of cementite to the depth of several mm beflow its sliding surface without inviting substantially any impairment of mechanical and physical properties of the base cast iron material and is provided with various characteristics, particularly excellent wear resistance, required for an apex seal used in a rotary piston'engine. Further, the cementite of the hardened layer is extremely stable even under high temperature atmosphere within the engine and the excellent impact decrement characterized by the cast iron of which the seal is made, prevents chatter marks (abnormal abrasion) from occurring, so it is possible to maintain the initial seal performance unchanged for a long time.
  • FIG. 1 is a perspective view illustrating a manner in which electron beam is applied
  • FIG. 2 is a perspective view illustrating external appearance in each step of the apex seal manufacturing process according to an embodiment of the present invention
  • FIG. 3 is a diagram showing transition of hardness below the sliding surface of the above-said apex seal, in comparison with a trial product obtained according to a conventional method where a chilling effect is used at the time of casting;
  • FIGS. 4 and 5 are the times magnified micro-photographs showing respectively the structures of the hardened layer and the boundary section in the apex seal produced according to the first embodiment
  • FIG. 6 is a thrice-magnified photograph of an end face of an apex seal produced according to the first embodiment of the present invention.
  • FIG. 7 is a photograph showing the conditions of the sliding surfaces, just after the bench tests, of the apex seals according to the first and second embodiments of the present invention.
  • an elongated cast iron blank 1 having a width b equal to or slightly larger than the width of the final product apex seal is prepared either by shaping from a cast mass or by cutting from a cast iron plate, cast iron block or the like.
  • the width b is of an extent in which final work allowance of the side 2 of the blank I, is included, while the length dimension 1 is one which corresponds to the length of one or several or more pieces of apex seal combined.
  • the term elongated as used herein is not limited in its meaning to a single apex length.
  • the cast iron material used may be of any type in which chilling can be performed, including ordinary cast iron, alloy cast iron, nodular graphite cast iron, malleable cast iron and others which are involved within the general category of cast iron. If desired, the cast iron material may be subjected previously to refining heat treatment.
  • blank 1 is placed in an electron beam radiator in which electron beams 3 are applied in a suitable manner to the top surface 5 of blank 1 which is travelling longitudinally at moving velocity V.
  • Application of electron beams may be conducted, for example, by projecting said beams continuously and swingingly in a direction perpendicular to the longitudinal axis of blank 1 such as to describe a zigzag trace 4, thereby to melt the blank material down to the depth of several m./rn. below the surface 5 of said blank.
  • the non-molten portion 6 produces an effect to that obtained when a chiller was attached, and the molten portion 7 is rapidly cooled by thischilling effect, resulting in formation of a chilled structure, namely, a hardened layer containing a large amount of cementite.
  • suitable selection of moving velocity of blank and electron beam radiating conditions will allow the top surface 5' of said blank to assume by itself after solidification a roundish configuration closely resembling the desired top surface of the iron bath.
  • the top surface 5 of blank 1 may be previously chamfeeeeoodcccccccc or otherwise worked into a desired roundish configuration. In either way, it is possible to form the top surface 5' into a roundish configuration.
  • the above-said melting operation may be conducted while cooling the nonmolten portion with suitable cooling means, for example, by attaching a well heat conductive chiller such as a copper plate to the side 2 and bottom surface 8 of said portion.
  • Blank material la which is initially prepared, is worked in next step into an intermediate or half-made article lb having at its top surface a rounded hardened layer 9, and then this intermediate article lb is subjected to finish work to form a final apex seal product 10.
  • EXAMPLE I A n elongated intermediate blank Ia, which is rec rectangular in section and has a size of 6.5 (b) X 12 (h) mm. and a length (I) of 70 mm., was prepared from nodular graphite cast iron (FCD 55- refer to G5502 of Japanese Industrial Standards) as shown in FIG. 2. The prepared blank was put in a welding chamber in an electron beam welder with an output of 1.25 kw. and electron beams were applied to said blank under the following conditions:
  • the top surface of the blank is instantaneously melted at a temperature of approximately l,500 C. by the irradiation of electron beam.
  • the thus-melted portion is then solidified in several seconds after the irradiation due to a chilling effect of the non-melted portion to form a hardened layer.
  • apex seal 10 having at its sliding surface a hardened layer 9 containing a large proportion of cementite was obtained.
  • the end face of the produced apex sea] as shown in FIG. 6 had a clearly visible hardened layer 9 (in FIG. 2), and this hardened layer, as shown in FIG. 4, had an extremely compact, perfectly chilled structure having Vickers hardness (VI-IN) of 780.
  • FIG. 1 Vickers hardness
  • FIG. 5 is a photograph showing the structure at the boundary section. Structural difference between the hardened layer and the base material of the apex seal is obvious from FIG. 5. Transition or gradient of hardness below the sliding surface of the thus obtained apex seal 1c is shown by a curve 10 in FIG. 3. As compared with hardness transition curve 11 of a trial product according to a conventional method using chiller at the time of casting, no impairment of characteristics of the base material is observed in the product of the present invention.
  • the apex seal produced by the conventional method has Vickers hardness of about 660 at the sliding surface, but the hardness is gradually lowered in proportion to the distance from the sliding surface. Hardness at the bottom surface is also as high as more than 450 in VHN. This means that the apex seal is chilled in its entirety and that its mechanical strength is too lowered to stand practical use.
  • the apex seal according to Example 1 of the present invention has high hardness of more than 750 (VHN) at the sliding surface and to the depth of about 2 mm. below said sliding surface, but hardness is sharply reduced as the distance from the sliding surface is in creased up to about 5 mm. below the sliding surface.
  • the apex seal of Example I of the present invention has a sliding surface which maintains always high hardness during use even if it is abraded, and that the characteristics of base material in the lower half of the apex seal are not the least impaired, allowing maintenance of mechanical strength sufficient' to stand practical use.
  • sliding surface hardness of more han 550 in VHN is sufficient for use, and best result is obtained when said hardness is more than 700. It is also desirable that the portion of at least one-third of the height of the apex seal remains unchanged or original in hardness and it has hardness of less than 400 in VHN.
  • the feeding rate of a blank may correspondingly be lowered if the beam current is decreased, and the frequency of beam'oscillation may be increased if the feeding rate of the blank is lowered.
  • the amplitude of the electron beam is determined depending upon the width of a desired apex seal and is desirable to be approximately equal to, or somewhat small than, the width of the desired apex seal.
  • the conditions under v which the electron beam irradiated widely vary with the size of a desired apex seal. The preferable conditions are as follows:
  • the irradiated blank was then subjected to stress-relieving heat treatment for about 2 hours with the result that it decreased from 900 to 750 VHN in hardness at its hardened layer and remained the same as the original hardness of 370 VHN at its lower portion.
  • the blank was subsequently given final working to obtain a desired apex seal therefrom.
  • stressrelieving heat treatment or stress relief tempering is effected in the above-mentioned step, it will be effective in preventing the hardened layer from breaking during the final working and also in preventing the layer from changing in hardness due to the temperature of an engine in which the apex seal obtained is fitted.
  • the apex seals according to Examples 1, 2 and 3 of the present invention showed high superiority in abrasion resistance over the conventional carbon type products, and also the casings in which the apex seals of the present invention were mounted suffered less abrasion loss. It was also confirmed that the devices of the present invention bring about remarkable improvement over the problem of reduction of gas sealing ability due to abrasion of end faces observed in the conventional carbon type or specific cast iron type products.
  • the Table also shows that the apex seal prepared from the acicular cast iron has better performance probably because said cast iron is superior in wear resistance and impact decrement.
  • the method for producing apex seals for rotary piston engine comprises substantially the steps of preparing an elongated cast iron blank having a width equal to or slightly larger than that of the final apex seal product, rapidly melting the top surface of said blank by application of electron beams or by other suitable means, then quickly cooling the molten portion by chilling effect of the non-molten portion, and finally subject ing same to suitable final works with or without previous stress-relieving heat treatment to thereby form a hardened layer of chilled structure containing a large amount of cementite at the sliding surface of the apex seal which is slidingly contacted with the inner surface of the casing.
  • a large amount of cementite can be integrally formed on the body cast iron material without impairing the characteristics of the latter to produce a structure having combined characteristics of said both materials, so that the resultant product has excellent properties such as strength, abrasion resistance, heat resistance and so forth required for practical use, as well as stabilized quality.
  • the apex seal according to the present invention can best be adapted in a chrome-plated portion being Usually, a hardened layer of this type is so hard that it sometimes proves difficult to exercise cutting or grinding operation.
  • final finish grinding or cutting operatiori can be conipleted in an extremely 'short time since the top surface of the blank after melting has already a configuration very near to the final shape of the sliding face of the finished apex sea].
  • This coupled with inexpensiveness of blank material, allows manufacture of the desired apex seals at low cost.
  • the present invention can be very highly appraised for its industrial utility.
  • An apex seal for a rotary piston engine which is an integral body made of cast iron or elongated shape and with a rounded sliding top surface and which comprises an upper and a lower portion, the former being a hardened portion including the sliding surface and telatterbeing a non-hardened portion, the hardened portion having chilled structure with a large proportion of cementite and a Vickers hardness of not less than 550, and the non-hardened portiobeing at least onethird of the seal in height and having a Vickers hardness of not more than 400.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatment Of Articles (AREA)
  • Sealing Devices (AREA)
  • Laser Beam Processing (AREA)
US71752A 1969-09-13 1970-09-14 Apex seal for rotary piston engine Expired - Lifetime US3658451A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP7291369A JPS4825289B1 (enrdf_load_stackoverflow) 1969-09-13 1969-09-13
JP7291269A JPS4825290B1 (enrdf_load_stackoverflow) 1969-09-13 1969-09-13

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US (1) US3658451A (enrdf_load_stackoverflow)
DE (1) DE2045125A1 (enrdf_load_stackoverflow)
FR (1) FR2061346A5 (enrdf_load_stackoverflow)
GB (1) GB1312997A (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3731941A (en) * 1970-12-12 1973-05-08 Nippon Piston Ring Co Ltd Facing materials for an internal combustion engine cylinder and a cooperating piston ring
US3830601A (en) * 1972-02-17 1974-08-20 Toyo Kogyo Co Apex sealing member for rotary piston engine
US3902830A (en) * 1972-02-21 1975-09-02 Nippon Piston Ring Co Ltd Side seal means for use in rotary piston internal combustion engine
US3947046A (en) * 1973-05-30 1976-03-30 Riken Piston Ring Kogyo Kabushiki Kaisha Oil seal ring for internal combustion engine
US4000011A (en) * 1971-09-09 1976-12-28 Toyo Kogyo Co., Ltd. Method of surface hardening
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
US4094618A (en) * 1976-03-31 1978-06-13 Toyo Kogyo Co., Ltd. Rotary piston engines
US4100664A (en) * 1975-01-17 1978-07-18 Caterpillar Tractor Co. Apex seal for rotary engines
US4125399A (en) * 1976-08-31 1978-11-14 Toyo Kogyo Co., Ltd. Apex seals for rotary piston engines
DE3212214A1 (de) * 1981-04-02 1982-10-28 Nippon Piston Ring Co., Ltd., Tokyo Kolbenring
WO1983004293A1 (en) * 1982-05-24 1983-12-08 Clark Eugene V Improvements in mechanical seal structures
US4545825A (en) * 1983-03-26 1985-10-08 Mazda Motor Corporation Apex seals for high power rotary piston engines
US4738602A (en) * 1985-12-06 1988-04-19 Mazda Motor Corporation Method for manufacturing an apex seal for a rotary piston engine using high energy heating radiation
US4863533A (en) * 1986-11-07 1989-09-05 Mazda Motor Corporation Apex seal for rotary piston engine and method for manufacturing the same
US5851014A (en) * 1995-07-15 1998-12-22 A E Goetze Gmbh Slide ring seal assembly for the running gears of track-laying vehicles
US6032720A (en) * 1997-01-14 2000-03-07 Tecumseh Products Company Process for making a vane for a rotary compressor
WO2005119017A1 (de) * 2004-06-02 2005-12-15 Schaeffler Kg Vorrichtung zur veränderung der steuerzeiten einer brennkraftmaschine
US20140147601A1 (en) * 2012-11-26 2014-05-29 Lawrence Livermore National Security, Llc Cavitation And Impingement Resistant Materials With Photonically Assisted Cold Spray

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2302119C3 (de) * 1973-01-17 1978-11-23 Audi Nsu Auto Union Ag, 7107 Neckarsulm Verfahren zur Herstellung einer Innendichtung für Rotationskolbenmaschinen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3180564A (en) * 1962-07-02 1965-04-27 Goetzewerke Radial seal for rotary piston engines

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3180564A (en) * 1962-07-02 1965-04-27 Goetzewerke Radial seal for rotary piston engines

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3731941A (en) * 1970-12-12 1973-05-08 Nippon Piston Ring Co Ltd Facing materials for an internal combustion engine cylinder and a cooperating piston ring
US4000011A (en) * 1971-09-09 1976-12-28 Toyo Kogyo Co., Ltd. Method of surface hardening
US3830601A (en) * 1972-02-17 1974-08-20 Toyo Kogyo Co Apex sealing member for rotary piston engine
US3902830A (en) * 1972-02-21 1975-09-02 Nippon Piston Ring Co Ltd Side seal means for use in rotary piston internal combustion engine
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
US3947046A (en) * 1973-05-30 1976-03-30 Riken Piston Ring Kogyo Kabushiki Kaisha Oil seal ring for internal combustion engine
US4100664A (en) * 1975-01-17 1978-07-18 Caterpillar Tractor Co. Apex seal for rotary engines
US4094618A (en) * 1976-03-31 1978-06-13 Toyo Kogyo Co., Ltd. Rotary piston engines
US4125399A (en) * 1976-08-31 1978-11-14 Toyo Kogyo Co., Ltd. Apex seals for rotary piston engines
DE3212214A1 (de) * 1981-04-02 1982-10-28 Nippon Piston Ring Co., Ltd., Tokyo Kolbenring
WO1983004293A1 (en) * 1982-05-24 1983-12-08 Clark Eugene V Improvements in mechanical seal structures
US4545825A (en) * 1983-03-26 1985-10-08 Mazda Motor Corporation Apex seals for high power rotary piston engines
US4738602A (en) * 1985-12-06 1988-04-19 Mazda Motor Corporation Method for manufacturing an apex seal for a rotary piston engine using high energy heating radiation
US4863533A (en) * 1986-11-07 1989-09-05 Mazda Motor Corporation Apex seal for rotary piston engine and method for manufacturing the same
US5851014A (en) * 1995-07-15 1998-12-22 A E Goetze Gmbh Slide ring seal assembly for the running gears of track-laying vehicles
US6032720A (en) * 1997-01-14 2000-03-07 Tecumseh Products Company Process for making a vane for a rotary compressor
US6053716A (en) * 1997-01-14 2000-04-25 Tecumseh Products Company Vane for a rotary compressor
WO2005119017A1 (de) * 2004-06-02 2005-12-15 Schaeffler Kg Vorrichtung zur veränderung der steuerzeiten einer brennkraftmaschine
US20140147601A1 (en) * 2012-11-26 2014-05-29 Lawrence Livermore National Security, Llc Cavitation And Impingement Resistant Materials With Photonically Assisted Cold Spray

Also Published As

Publication number Publication date
GB1312997A (en) 1973-04-11
DE2045125A1 (de) 1971-06-03
FR2061346A5 (enrdf_load_stackoverflow) 1971-06-18

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