US3836294A - Piston for rotary piston machines and means for its manufacture - Google Patents

Piston for rotary piston machines and means for its manufacture Download PDF

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Publication number
US3836294A
US3836294A US00315581A US31558172A US3836294A US 3836294 A US3836294 A US 3836294A US 00315581 A US00315581 A US 00315581A US 31558172 A US31558172 A US 31558172A US 3836294 A US3836294 A US 3836294A
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US
United States
Prior art keywords
piston
passage
face
outlet passage
outlet
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
US00315581A
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English (en)
Inventor
J Steinwart
M Ruf
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.)
Wankel GmbH
Audi AG
Original Assignee
Wankel GmbH
Audi AG
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 DE19712164646 external-priority patent/DE2164646C3/de
Application filed by Wankel GmbH, Audi AG filed Critical Wankel GmbH
Priority to US410803A priority Critical patent/US3865179A/en
Application granted granted Critical
Publication of US3836294A publication Critical patent/US3836294A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B55/00—Internal-combustion aspects of rotary pistons; Outer members for co-operation with rotary pistons
    • F02B55/02—Pistons
    • F02B55/04—Cooling thereof

Definitions

  • This invention relates to a piston for rotary piston machines. It is concerned in particular with a multiapex fluid-cooled piston, for example, of light alloy, of trochoidal type, which is provided in the region of its apices with cavities to which the coolant is fed from one face of the piston and from which the coolant is conducted away towards the other face of the piston. The invention is also concerned with means for manufacturing such a piston.
  • the aim of the invention is to provide a piston of which the cavities are arranged to allow manufacture by die-casting, yet without detracting from the flow of the coolant through the cavities from the one face of the piston to the other under the action of the alternating centrifugal acceleration forces.
  • the invididual cavities in the piston should each be formed by two converging passages of which the one serves as an inlet passage and starts from the one face of the piston and opens into the other passage which serves as the outlet passage and leads to the other face of the piston, and in the region of the point of entry the inlet passage into the outlet passage the outlet passage is wider in a circumferential direction than the inlet passage, and furthermore this point of entry lies at a point in the outlet passage which is spaced away from the radially outermost defining wall of the outlet passage.
  • each cavity to be produced by two mutually engaging core portions which, after casting, can be withdrawn inward along inclined radial paths in axially opposite directions.
  • the arrangement defined for the meeting point between the inlet passage and the outlet passage we largely prevent any reverse flow of coolant back through the inlet passage when negative, i.e., substantially radially inwardly directed, centrifugal acceleration forces arise.
  • the coolant, which is delivered from the inlet passage to the outlet passage by positive centrifugal forces i.e., those which are directed radially outward
  • positive centrifugal forces i.e., those which are directed radially outward
  • the inlet passages may start from an annular groove which is provided in the piston at its one face, and the outlet passages could lead into an annular groove which is provided in the piston at its other face and which is interrupted between adjacent apices of the piston by webs.
  • These annular grooves serve to cool the faces of the piston in the region of the so-called axial seals, i.e., the annular seals that are provided in the end faces of the piston.
  • the webs which interrupt the annular groove at the outlet face of the piston have the purpose of urging radially inwards the coolant which emerges from the individual cavities of the piston.
  • the piston can be made by dlie-casting, multipart cores being used to produce the cavities as is known in the production of reciprocating pistons.
  • a tool according to the invention for producing a piston comprises two cores which are capable of being withdrawn in mutually opposed directions, one of the cores having a hub and a number of movable core portions arranged around it, equal to the number of apices for forming the inlet passages and core portions for forming the inner surface of the piston between the inlet passages, and the other core likewise comprising a hub and a similar number of movable core portions arranged around it, equal to the number of apices, for forming the outlet passages and core portions for forming the inner surface of the piston between the outlet passages.
  • the engagement between the core portions of each core can be arranged so that after the hub has been withdrawn first the one set of movable core portions can be withdrawn and then the other core portions.
  • One of the hubs may carry, or itself form, a core for forming the central bearing opening of the piston.
  • a core with only a single hub may be used, the hub having the appropriate number of movable core portions on it for forming the outlet passages and also the appropriate number of core portions for forming the inner surface of the piston between the outlet passages.
  • the inlet passages are formed later by drilling them in the casting.
  • FIG. I is a longitudinal section through the piston along the line l-]l of FIG. 2;
  • FIG. 2 is a view looking in the direction of the arrow A in FIG. 1;
  • FIG. 3 is a view in the direction of the arrow B in FIG.
  • FIG. 4 is a longitudinal section through the piston and the associated mould and cores for casting it;
  • FIG. 4a is a partial section along the line Ark-Au in FIG. 4;
  • FIG. 6 is a section along the line l6-6 of FIG. 4.
  • FIGS. II to 3 we will describe first the piston il illustrated in FIGS. II to 3, and in the example illustrated this is formed as a light alloy casting and has three apices 2 and a central bearing opening 3.
  • the piston II is provided in the regions of the apices 2 with cavities to which a coolant is fed from the one face of the piston and from which the FIG. 5 is a section along the line 5-5 in FIG. 4; and
  • the individual cavities in the piston are each formed by two converging passages 4 and 5 which are free of undercuts and of which the passage 4 serves as an inlet passage and starts from the one face 6 of the piston and opens into the other passage 5.
  • This other passage 5 serves as the outlet passage and leads to the other face 7 of the piston.
  • the circumferential width of the outlet passage 5 is greater than that of the inlet passage 4 in the region where the inlet passage 4 enters it, and in addition the point of entry of the inlet passage 4 is spaced away from radially outermost defining wall 8 of the outlet passage 5. This is shown particularly clearly in FIG. 2.
  • the coolant emerging from the inlet passage 4 is flung against the outermost defining wall 8 of the outlet passage 5 and on further rotation of the piston it flows around the entry point of the passage 4 without flowing back into that passage 4.
  • the radially outermost wall 8 of the outlet passage 5 extends in a direction which is inclined with respect to the axis of rotation of the piston, as shown in FIG. 1.
  • the point 9 of maximum radial distance from the axis of rotation of the piston is axially displaced away from the point of entry of the inlet passage 4 in a direction towards the face 7 of the piston so that the coolant which has accumulated in this region under the action of the previous radially outwardly acting forces is not flung back into the inlet passage 4 but is flung against the radially innermost defining wall 10 of the outlet passage 5 and is guided away laterally.
  • the inlet passages 4 start from an annular groove 11 which is provided in the piston close to the face 6.
  • the coolant flowing into this groove 11 acts to cool the piston in the region where the so-called axial seals (formed in the face 6 but not shown) are present.
  • an annular groove 12 is provided in the other face of the piston, into which the outlet passages 5 open.
  • This groove 12 is interrupted between adjacent apices of the piston by web 13 (FIG. 2).
  • the coolant passing from the individual outlet passages 5 into the groove 12 is diverted radially inward at tHe webs 13 and is led away into the end portions of the housing in a known manner by appropriately placing passages.
  • FIGS. 4 to 6 a mould from producing the piston by die-casting.
  • This mould comprises an external mould portion made up,
  • the outer mould does not however form any part of the invention.
  • the core 15 has a hub 22 and three portions 17 of which projections 18 form the inlet passages 4.
  • the inner surface of the piston between the passages 4 is formed by three further core portions 19 on the hub 22.
  • the portions 17 and 19 have flat faces 20 and 21, respectively, which engage six faces of the hub 22, which is in the shape of a frus- .tum of a pyramid.
  • the core portions 17 and 19 are urged radially outward by the hub 22 in their operative position for casting, in which they engage a coreguiding bush 23.
  • the core 16 similarly contains three core portions 24 which are provided with extensions 25 for forming the outlet passages 5. Between these portions 24 there are portions 26 for forming the inner surface of the piston between the adjacent outlet passages.
  • the portions 24 and 26 have flat faces 27 and 28, respectively, by which they engage the six faces of a hub 29 and they are urged radially outward by this hub against a core-guiding bush 30.
  • the hub 29 has an extension 31 which defines the central bearing opening 3 of the piston.
  • the right-hand hub 22 and its associated core portions 17 and 21 can be omitted, and only the outlet passages 5 are formed by casting.
  • the inlet passages are formed by subsequent machining of the casting, the annular groove 11 also being machined.
  • the passages are formed by drilling, after the groove 11 has been turned.
  • a multi-apex piston for rotary piston machines of the trochoidal type provided with cavities in the region of the apices, to which coolant is supplied from the one face of the piston and from which the coolant is led away towards the other face of the piston, in which the individual cavities of the piston are each formed exclusively by two converging passages free of undercuts, of which the one passage serves as an inlet passage and starts from the one face of the piston and opens into the other passage which serves as an outlet passage and leads to the other face of the piston, and in the region of entry of the inlet passage into the outlet passage the outlet passage is circumferentially wider than the inlet passage, and moveover the point of entry of the inlet passage into the outlet passage is spaced away from the radially outermost defining wall of the outlet passage, and the outlet passage tapers slightly from the outermost defining wall to the other face of the piston.
  • a piston according to claim 1 in which the radially outermost defining wall of the outlet passage extends in a direction which is inclined to the axis of rotation of the piston in such a way that the point of its greatest radial distance from the axis is axially displaced away from the point of entry of the inlet passage in a direction towards the said other face of the piston.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
US00315581A 1971-12-24 1972-12-15 Piston for rotary piston machines and means for its manufacture Expired - Lifetime US3836294A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US410803A US3865179A (en) 1972-12-15 1973-10-29 Piston for rotary piston machines and means for its manufacture

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712164646 DE2164646C3 (de) 1971-12-24 Mehreckiger, flüssigkeitsgekühlter Kolben für Rotationskolbenmaschinen und Werkzeug zu dessen Herstellung

Publications (1)

Publication Number Publication Date
US3836294A true US3836294A (en) 1974-09-17

Family

ID=5829271

Family Applications (1)

Application Number Title Priority Date Filing Date
US00315581A Expired - Lifetime US3836294A (en) 1971-12-24 1972-12-15 Piston for rotary piston machines and means for its manufacture

Country Status (6)

Country Link
US (1) US3836294A (ref)
JP (1) JPS5514254B2 (ref)
FR (1) FR2165511A5 (ref)
GB (1) GB1378827A (ref)
IL (1) IL41099A (ref)
IT (1) IT972674B (ref)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100300402A1 (en) * 2009-05-19 2010-12-02 Dankwart Eiermann Rotary piston for a rotary piston engine and rotary piston engine
CN103282142A (zh) * 2010-12-23 2013-09-04 菲特尔莫古纽伦堡有限公司 内燃机活塞的铸造设备及打开或/和关闭铸造设备的方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3042009A (en) * 1958-10-02 1962-07-03 Nsu Motorenwerke Ag Cooling arrangement for rotary mechanisms
US3168237A (en) * 1961-09-09 1965-02-02 Nsu Motorenwerke Ag Rotor cooling arrangement for rotary mechanisms
US3206109A (en) * 1963-03-07 1965-09-14 Nsu Motorenwerke Ag Fluid cooling means for rotors of rotary mechanisms
US3261335A (en) * 1963-11-22 1966-07-19 Nsu Motorenwerke Ag Neckarsulm Outer body construction for rotary combustion engines
US3269370A (en) * 1962-11-28 1966-08-30 Nsu Motorenwerke Ag Rotor cooling means for rotary mechanism
US3333763A (en) * 1966-02-02 1967-08-01 Nsu Motorenwerke Ag Sealing arrangement for rotary engines

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3042009A (en) * 1958-10-02 1962-07-03 Nsu Motorenwerke Ag Cooling arrangement for rotary mechanisms
US3168237A (en) * 1961-09-09 1965-02-02 Nsu Motorenwerke Ag Rotor cooling arrangement for rotary mechanisms
US3269370A (en) * 1962-11-28 1966-08-30 Nsu Motorenwerke Ag Rotor cooling means for rotary mechanism
US3206109A (en) * 1963-03-07 1965-09-14 Nsu Motorenwerke Ag Fluid cooling means for rotors of rotary mechanisms
US3261335A (en) * 1963-11-22 1966-07-19 Nsu Motorenwerke Ag Neckarsulm Outer body construction for rotary combustion engines
US3333763A (en) * 1966-02-02 1967-08-01 Nsu Motorenwerke Ag Sealing arrangement for rotary engines

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100300402A1 (en) * 2009-05-19 2010-12-02 Dankwart Eiermann Rotary piston for a rotary piston engine and rotary piston engine
US8528518B2 (en) * 2009-05-19 2013-09-10 Wankel Supertec Gmbh Rotary piston for a rotary piston engine and rotary piston engine
CN103282142A (zh) * 2010-12-23 2013-09-04 菲特尔莫古纽伦堡有限公司 内燃机活塞的铸造设备及打开或/和关闭铸造设备的方法
US8985186B2 (en) 2010-12-23 2015-03-24 Federal-Mogul Nurnberg Gmbh Casting device for a piston for an internal combustion engine and method for opening and/or closing a casting device
CN103282142B (zh) * 2010-12-23 2016-01-20 菲特尔莫古纽伦堡有限公司 内燃机活塞的铸造设备及打开或/和关闭铸造设备的方法

Also Published As

Publication number Publication date
FR2165511A5 (ref) 1973-08-03
DE2164646A1 (de) 1973-07-05
JPS5514254B2 (ref) 1980-04-15
IL41099A0 (en) 1973-02-28
JPS4869909A (ref) 1973-09-22
DE2164646B2 (de) 1976-04-01
IL41099A (en) 1975-07-28
IT972674B (it) 1974-05-31
GB1378827A (en) 1974-12-27

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