US3924581A - Doweling construction for rotary engine housing - Google Patents
Doweling construction for rotary engine housing Download PDFInfo
- Publication number
- US3924581A US3924581A US530288A US53028874A US3924581A US 3924581 A US3924581 A US 3924581A US 530288 A US530288 A US 530288A US 53028874 A US53028874 A US 53028874A US 3924581 A US3924581 A US 3924581A
- Authority
- US
- United States
- Prior art keywords
- housing
- peripheral wall
- expansion
- dowel
- walls
- 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
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Classifications
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- 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
- F02B55/08—Outer members for co-operation with rotary pistons; Casings
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- 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
- F02B1/00—Engines characterised by fuel-air mixture compression
- F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
- F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
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- 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
- F02B53/00—Internal-combustion aspects of rotary-piston or oscillating-piston engines
- F02B2053/005—Wankel engines
Definitions
- the improved doweling construction for maintaining the housing parts of a rotary engine in their desired shape and relationship to each other comprises at least two dowels located on either side of the lobe junctions of the housing adjacent the top dead center (TDC) position of the rotor.
- One of the dowels is disposed to project through elongated openings in the end housing walls. The longitudinal axes of the openings are located so as to eliminate the resultant stress loading on the housing arising out of the differential rates of expansion between the end housing walls and the peripheral housing wall.
- DOWELING CONSTRUCTION FOR ROTARY ENGINE HOUSING This invention relates to rotary engines and, more particularly, to an improved doweling construction for maintaining the housing components of a rotary engine in their desired shape and relationship under normal operating conditions.
- the engine In rotary engines of the Wankel type, such as exemplified in the U.S. patent to Wankel et al, No. 2,988,065, the engine is provided with a housing or casing within which a rotor is supported for eccentric rotation relative to the housing.
- the housing comprises two end walls separated by a peripheral wall having an inner trochoidal shaped surface, the housing elements being secured together by through bolts. Since in Wankel type internal combustion rotary engines combustion takes place in one region or area and subjects the housing in this high heat flux and pressure region to substantial thermal and mechanical stresses which tend to distort the housing elements and force them out of alignment with each other, a dowel structure is provided in this high heat flux region to prevent the distortion and misalignment of the housing elements.
- dowel structures are exemplified in the U.S. Pat. Nos. to Bentele et al, 3,007,460, Bonner, 3,269,372 and to Jones, 3,715,178.
- each of the dowels engage at their shank portions both the peripheral housing wall and the end housing walls to resist the principal resultant thermal and gas pressure loads which are directed substantially radially relative to the axis of rotor rotation.
- these doweling constructions have not satisfactorily prevented misalignment and distortions caused by the secondary resultant loading directed somewhat parallel to a tangential plane to the trochoidal surface adjacent the dowels due to the different rates of expansion of the housing end walls and the peripheral wall.
- This secondary loading is particularly pronounced in engine housings having end walls and a peripheral wall of different coefficients of expansion, as for example, an engine housing having a peripheral wall of aluminum and at least one end wall of cast iron.
- the present invention therefore has for its prime purpose to provide an improved dowel structure for a rotary engine wherein the housing components or elements expand differently due to different thermal gradients and/or because of different coefficients of expansion.
- the improved dowel structure comprises at least two dowels located in the area or region of high stress and on opposite sides of the lobe junction of the housing adjacent the top dead center (TDC) position of the rotor and with one of the dowels disposed so that its shank portion projects through an elongated opening in each of the end walls of the housing.
- the longitudinal axes of the openings are located so as to extend somewhat parallel to an imaginary, substantially tangential line to the adjacent trochoidal surface of the peripheral housing wall. This elongated opening prevents transmission between the end walls and trochoid wall, via the dowel, of the resultant loading caused by differences in the thermal and pressure deflections and/or the different rates of thermal expansion between the peripheral wall and end walls.
- FIG. 1 is an axial view of a rotary engine having a dowel structure according to this invention and with part of one end wall broken away for illustration purposes;
- FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. land on a somewhat enlarged scale;
- FIG. 3 is a fragmentary view in elevation of the dowel as shown in FIG. 2.
- the reference number 10 generally designates a rotary internal combustion engine of the Wankel type, such as shown in the U.S. Pat. to Wankel et al, No. 2,988,065.
- the engine comprises a multi-part or multi-component outer body or housing 12 having a cavity within which an inner body or rotor 14 is eccentrically supported on a shaft 16 for planetary rotation.
- the housing 12 comprises two end walls 18 and 20 axially spaced apart by a peripheral wall 22 having an inner peripheral trochoidal surface 24.
- the end walls 18 and 2.0 and peripheral wall 22 are held together by a plurality of the bolts 25.
- the housing cavity is of the two lobe type with the lobes meeting at lobe junctions 26 and 28 and therefore rotor 14 is shown as being generally triangular in profile with arcuate shaped shank portions 30 converging at apex portions 32.
- the rotor 14 and housing 12 define therebetween three working or combustion chambers 34, each of which successively expand and contract in volumetric size as the rotor planetates relative to the housing.
- Fuel for combustion in the chambers is provided for by an intake port 36 in end wall 20, through which intake port 36 passes a mixture of fuel and air from a suitable source such as a carburetor.
- a spark plug 38 is secured in peripheral wall 22.
- Discharge of the spent products of combustion from chambers 34 is achieved by an exhaust port 39 located in peripheral housing wall 22.
- suitable means may be provided to achieve combustion in chambers 34 without departure from the scope and spirit of this invention.
- only air may be introduced through intake port 36 with fuel injected in the chambers via an injector nozzle (not shown).
- the engine may function as a diesel instead of being a spark ignited, Otto cycle engine, as shown.
- the improved dowel structure of this invention comprises at-least two dowel assemblies 40 and 40A in the high stress area on opposite sides of lobe junction 26.
- One or more additional dowel assemblies 40 may be located elsewhere on the housing (only one additional dowel assembly being shown in FIG. 1).
- Each dowel assembly 40 comprises a tubular dowel 42 which extends through aligned or registered holes in ears 44 formed integrally with end walls 18 and and peripheral wall 22.
- the dowel 42 is pressfitted or otherwise suitably secured in the holes in the ears of peripheral wall 22.
- dowel assembly 40A comprises a tubular dowel 42A, similar to dowels 42 of dowel asemblies 40, which projects through and is pressfitted in aligned holes 46 in ears 48 formed integrally with peripheral wall 22. Also, dowel 42A passes through an elongated opening or slot 50 in ears 52, similar to ears 44, formed integrally with end walls 18 and 20. Alternatively to pressfitting dowel 42A in place, dowel 42A may be clamped in position by a tie bolt (not shown) which extends therethrough and washers (not shown) disposed to abut opposite ends of dowel 42A and the nut and head of such tie bolt. As shown in FIG.
- each of the slots 50 is dimensioned so that its width is such as to snugly receive dowel 42A and thereby permits dowel 42A. to absorb, together with one or more dowels 40, the radially directed primary resultant thermal and pressure load.
- the length of each of the slots 50 is such as to permit relative movement of the dowel and the end walls associated with each of the slots.
- Each slot 50 is located so that its longitudinal axis AA extends in a plane somewhat parallel to an imaginary tangent line T-T to the trochoidal surface adjacent dowel assembly 40A.
- This relationship of the longitudinal axis AA of the slot to the trochoidal surface 24 is important to permit relative movement of dowel 42A and end walls 18 and 20 and thereby relieve the resultant stress loading due to the different thermal gradients in end walls 18 and 20 and peripheral wall 22, which resultant loading stress is directed somewhat parallel to the imaginary tangent line T-T.
- This resultant stress loading is secondary to the primary thermal and gas pressure loads directed substantially radially relative to the axis of shaft 16. It has been found that this secondary resultant stress loading, unless relieved, causes distortion and misalignment of the housing end walls 18 and 20 and peripheral wall 22.
- housing 12 By allowing relative movement of dowel 42A and slots 50 and hence relative movement between end walls 18 and 20 and peripheral wall 22 in this area of high stress and, under this secondary stress loading, the integrity of housing 12 is better maintained than in heretofore known dowel structures, such as exemplified in the U.S. Pat. Nos. to
- this secondary stress load is due to the difference in thermal gradients between end walls 18 and 20 and peripheral wall 22 because different thermal gradients in those housing components occurs despite efforts at control through regulating liquid cooling flow rates through such housing walls.
- This secondary stress load is particularly pronounced where housing 12 comprises end walls constructed of material having a different coefficient of expansion than the material of which peripheral wall 22 is made.
- the herein described invention provides in a rotary internal combustion engine of the Wankel type an improved dowel structure for the engine housing which obviates distortion and misalignment due to the different growth rates of the housing elements or by reason of housing elements made of material having different coefficients of expansion. It is a dowel structure which compensates for both primary and secondary stress loadings.
- a rotary internal combustion engine having a housing consisting of a pair of spaced, substantially parallel end walls and a peripheral wall having a trochoidal shaped inner surface, the end and peripheral walls defining therebetween a cavity in which a rotor is mounted for planetary rotation and which defines with said walls working chambers which successively expand and contract in volumetric size as the rotor rotates relative to the housing, wherein combustion occurs in the working chambers adjacent one area of the housing exposing that area to relatively higher temperatures and pressures than in the remainder of the housing whereby said area is subjected to high stresses, and wherein at least one end wall and the peripheral wall have different rates of expansion than the other housing walls which differential expansion would tend to subject the housing to additional stress, an improved dowel structure for maintaining alignment of said end walls and peripheral wall, comprising:
- one of the dowels being disposed to project through an elongated opening in the end wall having a different rate of expansion
- said elongated opening having a longitudinal axis extending in a direction to obviate the additional resultant stress loading on the housing arising out of the differential rate of expansion between the end wall and said peripheral wall.
- peripheral wall and said end wall is made of material having different coefficients of expansion.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Rotary Pumps (AREA)
Abstract
Description
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US530288A US3924581A (en) | 1974-12-06 | 1974-12-06 | Doweling construction for rotary engine housing |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US530288A US3924581A (en) | 1974-12-06 | 1974-12-06 | Doweling construction for rotary engine housing |
Publications (1)
Publication Number | Publication Date |
---|---|
US3924581A true US3924581A (en) | 1975-12-09 |
Family
ID=24113109
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US530288A Expired - Lifetime US3924581A (en) | 1974-12-06 | 1974-12-06 | Doweling construction for rotary engine housing |
Country Status (1)
Country | Link |
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US (1) | US3924581A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090211103A1 (en) * | 2004-07-23 | 2009-08-27 | Richard John Pretlove | Cutter assembly and method of producing same |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007460A (en) * | 1960-03-29 | 1961-11-07 | Curtiss Wright Corp | Cooling arrangement for rotary mechanisms |
US3269372A (en) * | 1964-06-03 | 1966-08-30 | Curtiss Wright Corp | Through dowel construction for rotary mechanisms |
US3451215A (en) * | 1967-04-03 | 1969-06-24 | Gen Electric | Fluid impingement starting means |
US3715178A (en) * | 1971-11-30 | 1973-02-06 | Curtiss Wright Corp | Doweling construction for rotary engine housing |
-
1974
- 1974-12-06 US US530288A patent/US3924581A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007460A (en) * | 1960-03-29 | 1961-11-07 | Curtiss Wright Corp | Cooling arrangement for rotary mechanisms |
US3269372A (en) * | 1964-06-03 | 1966-08-30 | Curtiss Wright Corp | Through dowel construction for rotary mechanisms |
US3451215A (en) * | 1967-04-03 | 1969-06-24 | Gen Electric | Fluid impingement starting means |
US3715178A (en) * | 1971-11-30 | 1973-02-06 | Curtiss Wright Corp | Doweling construction for rotary engine housing |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090211103A1 (en) * | 2004-07-23 | 2009-08-27 | Richard John Pretlove | Cutter assembly and method of producing same |
US7900360B2 (en) | 2004-07-23 | 2011-03-08 | The Gillete Company | Cutter assembly and method of producing same |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: JOHN DEERE TECHNOLOGIES INTERNATIONAL, INC., JOHN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CURTISS-WRIGHT CORPORATION, A CORP. OF DE;REEL/FRAME:005646/0925 Effective date: 19840223 |
|
AS | Assignment |
Owner name: SNYDER, SHERYL K. Free format text: SECURITY INTEREST;ASSIGNOR:ROTARY POWER INTERNATIONAL, INC., A CORPORATION OF DE;REEL/FRAME:006027/0113 Effective date: 19920220 Owner name: LOEB PARTNERS CORPORATION Free format text: SECURITY INTEREST;ASSIGNOR:ROTARY POWER INTERNATIONAL, INC., A CORPORATION OF DE;REEL/FRAME:006027/0122 Effective date: 19920220 Owner name: SNYDER, LARRY L. Free format text: SECURITY INTEREST;ASSIGNOR:ROTARY POWER INTERNATIONAL, INC., A CORPORATION OF DE;REEL/FRAME:006027/0113 Effective date: 19920220 |
|
AS | Assignment |
Owner name: ROTARY POWER INTERNATIONAL, INC., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:JOHN DEERE TECHNOLOGIES INTERNATIONAL, INC.;REEL/FRAME:006031/0870 Effective date: 19911231 |