Rotary Device Including A Counterbalanced Seal Assembly

Abstract

A rotary device is provided. The rotary device includes a housing having an inner surface and a rotor assembly mounted for rotation in the housing about an axis defining an axial direction of the rotary device. The rotor assembly includes a rotor and a seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. Each arm has a distal end disposed for sliding engagement with the inner surface, and at least one of the arms has a channel defined therein. The seal assembly is disposed within the channel, and includes a seal, a base defining a seal channel configured to receive the seal, and a counterweight mechanism pivotally coupled to the base. The counterweight mechanism is configured to control a contact pressure exerted by the seal on the inner surface resulting from rotation of the rotor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent application Ser. No. 14/472,048, filed Aug. 28, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] The field of the disclosure relates generally to rotary devices, and more particularly, to crossover seals used in such devices.

[0003] Rotary devices, such as internal combustion rotary engines, generally include a housing and a rotor positioned within the housing for rotation. The rotor separates the housing into one or more chambers in which fluids, such as gases or liquids, are received, compressed, combusted, and/or expelled. In rotary engines, combustion of compressed air-fuel mixtures within such chambers causes a rapid expansion of gas, which causes the rotor to rotate. Rotation of the rotor can be used to power various devices, such as vehicles, compressors, pumps, and other devices.

[0004] Rotors within such rotary devices typically include seals, commonly referred to as apex or crossover seals, disposed at a distally outward portion of the rotor. Apex seals are designed to form a seal with the housing of the rotary device to seal adjacent chambers from one another to prevent leakage of gas from one chamber to another. Some rotary devices also use springs to bias the apex seals against the housing to ensure sufficient contact pressure between the seal and the housing to maintain a seal between adjacent chambers.

[0005] Rotation of the rotor imparts centrifugal forces on apex seals, which increases the contact pressure between the seals and the housing as the rotational speed of the rotor increases. When operated at relatively high rotational speeds, centrifugal forces acting on the apex seals can result in rapid wear of the seals, particularly where springs are used to bias the seals against the housing. Such wear results in an undesirable decrease in the service life of apex seals.

[0006] Some known rotary devices have omitted springs, and rely on centrifugal forces to force the apex seals against the housing. However, operation of such devices at relatively low rotational speeds has not been adequate because of insufficient sealing between adjacent chambers.

BRIEF DESCRIPTION

[0007] In one aspect, a rotary device is provided. The rotary device includes a housing having a cylindrical inner surface and a rotor assembly mounted for rotation in the housing. The rotor assembly includes a rotor, at least one rocker pivotally coupled to the rotor, and a counterbalanced seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. Each arm has a distal end disposed for sliding engagement with the inner surface. The rocker pivots between a first position spaced from the inner surface of the housing and a second position adjacent the inner surface of the housing. Pivoting of the rocker causes the rotor to rotate. The counterbalanced seal assembly is disposed at the distal end of at least of one of the arms, and includes a seal and a counterweight mechanism. The counterweight mechanism is configured to control a contact pressure exerted by the seal on the inner surface resulting from rotation of the rotor.

[0008] In another aspect, a rotor assembly for use in a rotary device is provided. The rotor assembly includes a rotor, at least one rocker pivotally coupled to the rotor, and a counterbalanced seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. The central portion and the plurality of arms define a plurality of chambers extending radially outward from the central portion. The rocker pivots between a first position proximate the central portion and a second position distal from the central position. Pivoting of the rocker causes the rotor to rotate. The counterbalanced seal assembly is configured to inhibit fluid flow between adjacent chambers of the plurality of chambers. The counterbalanced seal assembly includes a seal and a counterweight mechanism configured to control radial displacement of the seal resulting from centrifugal forces imparted on the seal by rotation of the rotor.

[0009] In yet another aspect, a rotary device is provided. The rotary device includes a housing having an inner surface and a rotor assembly mounted for rotation in the housing. The rotor assembly includes a rotor, at least one rocker pivotally coupled to the rotor, and a seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. Each arm has a distal end disposed for sliding engagement with the inner surface. The rocker pivots between a first position spaced from the inner surface of the housing and a second position adjacent the inner surface of the housing. Pivoting of the rocker causes the rotor to rotate. The seal assembly is disposed at the distal end of at least of one of the arms, and includes a seal and a control mechanism operably coupled to the seal. The control mechanism is configured to exert a variable radial force on the seal to control a contact pressure exerted by the seal on the inner surface resulting from rotation of the rotor.

[0010] In yet another aspect, a rotary device is provided. The rotary device includes a housing having an inner surface, and a rotor assembly mounted for rotation in the housing about an axis defining an axial direction of the rotary device. The rotor assembly includes a rotor and a seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. Each arm has a distal end disposed for sliding engagement with the inner surface of the housing, and at least one of the arms has a channel defined therein. The seal assembly is disposed within the channel. The seal assembly includes a seal, a base defining a seal channel configured to receive the seal, and a counterweight mechanism. The counterweight mechanism is pivotally coupled to the base, and is configured to control a contact pressure exerted by the seal on the inner surface of the housing resulting from rotation of the rotor.

[0011] In yet another aspect, a seal assembly for use in a rotary device including a rotor is provided. The seal assembly includes a seal, a base, and a counterweight mechanism. The base defines a seal channel extending in a longitudinal direction. The seal is disposed within the seal channel. The counterweight mechanism is pivotally coupled to the base, and is configured to control radial displacement of the seal resulting from centrifugal forces imparted on the seal by rotation of the rotor.

[0012] In yet another aspect, a rotary device is provided. The rotary device includes a housing having an inner surface and a rotor assembly mounted for rotation in the housing about an axis defining an axial direction of the rotary device. The rotor assembly includes a rotor and a seal assembly. The rotor includes a central portion and a plurality of arms extending radially outward from the central portion. Each arm has a distal end disposed for sliding engagement with the inner surface of the housing, and at least one of the arms has a channel defined therein. The seal assembly is disposed within the channel, and comprises a seal, a base, and a counterweight mechanism. The seal includes a body and lip extending outward from the body. The base defines a seal channel, and includes a fulcrum. The seal is disposed within the seal channel. The counterweight mechanism is operatively coupled to the fulcrum, and includes a counterweight and a lever extending away from the counterweight. Rotation of the rotor causes the counterweight mechanism to pivot about the fulcrum and causes the lever to exert a radial inward force on the lip.

[0013] In yet another aspect, a seal assembly for use in a rotary device including a rotor is provided. The seal assembly includes a seal, a base, and a counterweight mechanism. The seal includes a body and a lip extending outward from the body. The base defines a seal channel, and includes a fulcrum. The seal is disposed within the seal channel. The counterweight mechanism is operatively coupled to the fulcrum, and includes a counterweight and a lever extending away from the counterweight. Rotation of the rotor causes the counterweight mechanism to pivot about the fulcrum, and causes the lever to exert a radial inward force on the lip.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is perspective view of an exemplary rotary engine.

[0015] FIG. 2 is an exploded view of the rotary engine shown in FIG. 1, illustrating a housing and a rotor assembly of the rotary engine.

[0016] FIG. 3 is an exploded view of the rotary engine's rotor assembly shown in FIG. 2, illustrating a rotor, a plurality of rockers, an outer crankshaft, and a main crankshaft of the rotor assembly.

[0017] FIG. 4 is a cross-sectional view of the rotary engine of FIG. 1 within a vehicle.

[0018] FIG. 5 is a front view of the rotor shown in FIG. 3.

[0019] FIG. 6 is a partial front view of the rotor shown in FIG. 3, illustrating one of the rockers in a first position.

[0020] FIG. 7 is a partial front view of the rotor shown in FIG. 3, illustrating the rocker of FIG. 6 in a second position.

[0021] FIG. 8 is perspective view of an exemplary rocker of the rotor shown in FIG. 3.

[0022] FIG. 9 is an exploded view of an exemplary outer crankshaft of the rotor shown in FIG. 3.

[0023] FIG. 10 is a perspective front view of the housing of the rotary engine shown in FIG. 1.

[0024] FIG. 11 is a perspective rear view of the housing of the rotary engine shown in FIG. 10 including cooling jackets.

[0025] FIG. 12 is a perspective view of the rotor shown in FIG. 3.

[0026] FIG. 13 is a perspective view of the main crankshaft shown in FIG. 3.

[0027] FIG. 14 is a front view of an exemplary two-chambered rotor suitable for use in a rotary engine

[0028] FIG. 15 is a perspective view of an exemplary dual unit rotary engine including two rotary engines.

[0029] FIG. 16 is a perspective view of an alternative ring plate suitable for use with the rotary engine shown in FIG. 1.

[0030] FIG. 17 is a perspective view of another alternative ring plate suitable for use with the rotary engine shown in FIG. 1.

[0031] FIG. 18 is a perspective view of a replacement part suitable for use with the rotary engine shown in FIG. 1.

[0032] FIG. 19 is a perspective view of an exemplary seal suitable for use with the rotary engine shown in FIG. 1.

[0033] FIG. 20 is a perspective view of an exemplary housing suitable for use with rotary-type compressor.

[0034] FIG. 21 is a perspective view of an alternative spur gear suitable for use with the rotary engine shown in FIG. 1.

[0035] FIG. 22 is a perspective view of an alternative rotor suitable for use with the rotary engine shown in FIG. 1.

[0036] FIG. 23 is an exploded view of an exemplary housing including a sleeve suitable for use with the rotary engine shown in FIG. 1.

[0037] FIG. 24 is a cross-sectional view of an exemplary rotor suitable for use with the housing and the rotor assembly shown in FIG. 2, the rotor including a counterbalanced seal assembly.

[0038] FIG. 25 is an enlarged partial view of the rotor shown in FIG. 24, illustrating details of the counterbalanced seal assembly.

[0039] FIG. 26 is a side view of an exemplary seal suitable for use in the counterbalanced seal assembly shown in FIG. 25.

[0040] FIG. 27 is a perspective view of a portion of the seal shown in FIG. 26

[0041] FIG. 28 is a perspective view of an exemplary counterweight mechanism suitable for use in the counterbalanced seal assembly shown in FIG. 25.

[0042] FIG. 29 is a partial cross-sectional view of a rotor arm including an alternative embodiment of a counterbalanced seal assembly that includes a control mechanism.

[0043] FIG. 30 is a partial perspective view of a rotor arm including another alternative embodiment of a counterbalanced seal assembly.

[0044] FIG. 31 is a partial perspective view of the rotor arm of FIG. 30 illustrating the counterbalanced seal assembly of FIG. 31 removed from the rotor arm.

[0045] FIG. 32 is a partially exploded view of the counterbalanced seal assembly of FIG. 31.

[0046] FIG. 33 is a partially exploded view of yet another alternative embodiment of a counterbalanced seal assembly.

[0047] FIG. 34 is a partial perspective view of a rotor assembly in which the counterbalanced seal assembly of FIG. 33 is installed.

[0048] FIG. 35 is an exploded view of yet another alternative embodiment of a counterbalanced seal assembly.

[0049] FIG. 36 is an end view of the counterbalanced seal assembly of FIG. 35.

[0050] Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. Any feature of any drawing may be referenced and/or claimed in combination with any feature of any other drawing.

DETAILED DESCRIPTION

[0051] FIG. 1 is a perspective view of an exemplary rotary engine 100, and FIG. 2 is an exploded view of rotary engine 100. Rotary engine 100 includes a housing 200 for housing other components and for mounting in a vehicle or other device, a rotor assembly 300 (broadly, a power module), and an output member 600 (broadly, an output).

[0052] Housing 200 may include a generally cylindrical housing body 202 of 8620, 8514 or other steel or iron alloy. Aluminum or other suitable materials also could be used. Housing body 202 has a cylindrical inner wall or surface 204. In some embodiments, inner wall 204 is defined by a steel insert or sleeve received within an outer housing body (see, e.g., FIG. 23).

[0053] Housing 200 may be air- or water-cooled. If water-cooled, housing 200 may have top and bottom water troughs 210 and 220 (FIGS. 10 and 11). A top water jacket 212, which covers top water trough 210, has an inlet 214 and an outlet 216 (FIG. 10). Likewise, a bottom water jacket 222, which covers bottom water trough 220, has an inlet 224 and an outlet 226. The inlets may receive coolant from a radiator or other heat exchanger, and the outlets return the coolant to the radiator. Hoses connecting the inlet and outlet to the radiator are not shown. The troughs may have vanes 218 and 228 of heat conductive material to transfer heat from the housing to the coolant. The vanes also may direct the coolant to flow from the inlet to the outlet. In addition, one could change the locations of the inlet and outlet or the orientation of the vanes 218, 228. In one embodiment, for example, vanes 218, 228 may extend parallel to an axial direction of housing 200.

[0054] A front plate 230 and a rear plate 232 enclose housing 200 (FIGS. 1 and 2). Plates 230 and 232 may be 6061 aluminum or other suitable material. The terms "front" and "rear" are used with reference to the drawings, not necessarily with reference to a vehicle or another device in which the rotary engine mounts. Housing body 202 has circumferentially spaced bores extending into the front and back of the housing body. Only bores 234 on the front of housing 200 are visible in FIGS. 2, 4, 10, and 11. Bolts or other fasteners (not shown) extend through corresponding holes 236 in front plate 230 and lock into the bores. Housing body 202 may have openings and ports that are discussed in more detail below.

[0055] Front and rear plates 230 and 232 may include an oil ring seal groove 238 (only shown on plate 232 in FIG. 2). Corresponding ring seals (see seal 532 in FIG. 19) seat in the ring seal grooves to create a seal when the plates attach to housing body 202. Gaskets (not shown) also may seal the plates to the housing body. Other devices or systems may be provided to prevent galvanic corrosion due to the dissimilar metals.

[0056] A rotor assembly 300 (broadly, a power module) is mounted for rotation within housing body 202. Rotor assembly 300 includes a rotor 310 that rotates about an axis of rotation within housing body 202. Rotor 310 may be formed of 8620 or 8514 steel or ductile iron. Rotor 310 may have four arms 312, 314, 316 and 318 (FIGS. 5, 6, 7, and 12). The distal end of each arm, e.g., end 320 of arm 312 (FIGS. 5 and 7), has two short, spaced-apart extensions 322 and 324 (FIGS. 6 and 7). Outer faces 326 and 328 of extensions 322 and 324 (FIGS. 3, 6, and 7) may have surfaces that conform to inner wall 204 of housing body 202 for sliding engagement with cylindrical inner wall 204. In the embodiment illustrated in FIG. 3, pressure plates 330, which may be 9254 steel, seat in the space between extensions 322 and 324. Spring 332, which may be made of Incoloy.RTM. alloy, urges pressure plate 330 to push seals 306 and 308 (FIG. 3) to seal against cylindrical inner wall 204. Pressure plate seals and arm extensions, such as extensions 322 and 324, seal the distal ends of the arms to the inside cylindrical wall 204 of the housing body 202. Remaining arms 314, 316 and 318 have similar arrangements.

[0057] Arms 312, 314, 316 and 318 may be formed from two plates 340 and 342 that extend outward from a central portion, i.e., hub 344 (FIG. 12) and form a hollow space 336 between plates 340 and 342. Only the plates that form arm 312 in FIG. 12 are numbered. The hollow space is used by outer crankshafts as described below. In addition, having spaced-apart plates may decrease rotor mass and increase efficiency.

[0058] Plates for arms 312, 314, 316 and 318 may have aligned bores. FIG. 12 shows bores 350, 352, 354 and 356 in plate 340. Only bore 358 in plate 342 is visible. Bores 350, 352, 354 and 356 align with corresponding bores in plate 342.

[0059] Referring to FIG. 5, a plurality of chambers 360, 362, 364, and 366 are defined by pairs of adjacent arms 312, 314, 316, and 318, and inner cylindrical wall 204. In the illustrated embodiment, chamber 360 (FIG. 5) is formed between arms 312 and 318, and the spaces between arms 312 and 314, 314 and 316 and 316 and 316, form chambers 362, 364 and 366, respectively.

[0060] A plurality of rockers 370, 372, 374 and 376 are pivotally connected to rotor 310 for pivoting between a first, inner position spaced from inner wall 204 (shown in FIG. 6), and a second, outer position adjacent inner wall 204 (shown in FIG. 7). One of four rockers 370, 372, 374 and 376 is mounted for pivoting within each chamber 360, 362, 364 and 366. FIG. 3 shows rocker 376 exploded from the rotor, FIG. 5 shows each rocker 370, 372, 374 and 376 in relation to rotor 310, and FIG. 8 shows an enlarged view an exemplary rocker. Rockers 370, 372, 374 and 376 may be formed from 4032 aluminum or other appropriate material.

[0061] As shown in FIGS. 5 and 8, a pivot pin 380 extends through a ridge 382 of each rocker 370, 372, 374 and 376 (only one pin labeled in FIG. 5). Ridge 382 mounts in a rounded portion 384 of each arm 312, 314, 316 and 318. An outer surface of ridge 382 cooperates with a surface of rounded portion 384 to seal ridge 382 and rounded portion 384 intersection as the rocker pivots. Added structure may be provided to enhance the seal at ridge 382 such as a sealing member 428 (FIG. 3) proximate ridge 382 (FIG. 8). Rockers 370, 372, 374 and 376 may have a front groove 404 and side grooves (e.g., groove 406 shown in FIG. 8). Side compression seals 424 and 426 (FIG. 3) mount in the side grooves and front compression seal 428 seats in front groove 404. Side compression seals 424 and 426 and front compression seal 428 may be 5254 steel. Side compression seals 424 and 426 contact the inside of front ring plate 396 and rear ring plate 398 when ring plates 394 and 396 are mounted to the outside of rotor 310 (FIG. 3). Front compression seal 428 contacts the rocker face of each rotor arm, e.g., face 368 of arm 312 (FIG. 5). The rocker faces may be arcuate around the axis of each pivot pin. The rocker faces also close off the space between the two plates. Seals 306 and 308 (FIG. 3) may seat in circumferential grooves 334 of ring plates 396 and 398 (only groove 334 in ring plate 396 is labeled in FIG. 3). Each seal 306 and 308 may have inward facing portions 504 and 506 (only inward facing portions 504 and 506 on seal 306 are labeled in FIG. 3). Inward facing portions 504 and 506 contact each other to form a seal. Inward facing portions 504 and 506 may extend from the circumferential grooves though a notch in the ring plate, e.g., notch 508. When the device is assembled, seals 306 and 308 seal the outside of chambers 360, 362, 364 and 366.

[0062] One may want to change parts if one of the rocker faces (e.g., rocker face 368 shown in FIG. 5) becomes damaged or worn. Therefore, rotor 310 may be designed to accept a replacement part with an undamaged or unworn face, such as replacement part 378 (shown in FIG. 18).

[0063] Referring again to FIG. 3, front and rear ring plates 396 and 398 cover rotor arms 312, 314, 316 and 318, chambers 360, 362, 364 and 366 and rockers 370, 372, 374 and 376. Ring plates 396 and 398 may be formed of ductile iron. Front ring plate 396 has four cutouts 484, 486, 488 and 490. Each cutout 484, 486, 488 and 490 aligns with one of bores 350, 352, 354 or 356 in a respective rotor arm 312, 314, 316 and 318 (shown in FIGS. 6 and 7). Rear ring plate 398 also has four cutouts 496, 498, 500 and 502 (FIG. 3). Each cutout 496, 498, 500 and 502 aligns with a corresponding cutout on front ring plate 396.

[0064] Pivot pin 380 may extend into bores, such as bores 394 on front ring plate 396 (FIG. 3) and to corresponding bores (not numbered) on rear ring plate 398. Pivot pin 380 may also extend into recesses, which extend into but not through the ring plates. Bores 388, 390 and 392 and the other unnumbered bores on the ring plate can be used for bolting front ring plate 396 to rotor 310. Corresponding bolts or other fasteners attach rear ring plate 398 to rotor 310. The fasteners (not shown) attach to threaded bores 386 (shown FIGS. 3-7) on rotor arms 312, 314, 316 and 318. The bores' positions used to attach the ring plates can vary.

[0065] For positioning by hand, dowels may be used to align appropriate holes, e.g., hole 388 in ring plates 396 or 398, with the appropriate bore 386. Automated assembly may use different techniques.

[0066] Referring again to FIG. 8, rocker 376 may include two spaced-apart pin bosses 410 and 412, which may be integrally formed as part of rocker 376. Rocker rod pin 414, which may be 4140 steel, extends through bores 416 in pin boss 410 (only one visible in FIG. 8). Rocker rod pin 414 also extends through the upper bore 420 of link 418 (shown FIGS. 3 and 8). A lower bore 422 of link 418 is also shown in FIG. 3. Link 418 also may be 4140 steel. Rockers 370, 372, and 374 may have the same configuration as rocker 376 shown in FIG. 8.

[0067] Rockers 370, 372, 374 and 376 pivot about their respective pivot pins, e.g., pin 380 in rocker 376 (FIG. 5). Each rocker 370, 372, 374 and 376 pivots between an outside position, which is close to inner wall 204 of housing body 202, to an inside position away from inner wall 204, and back to the outside position. Thus, in FIG. 5, rockers 370 and 374 are shown in the inside positions, and rockers 372 and 376 are shown in the outside positions. These positions are temporary because rockers 370, 372, 374 and 376 pivot in and out as described below.

[0068] Pivoting of each rocker 370, 372, 374 and 376 rotates a corresponding outer crankshaft 430, 432, 434 and 436 (FIG. 5). Likewise, rotating an outer crankshaft pivots its corresponding rocker. Outer crankshafts 430, 432, 434 and 436 may be made of 4140 steel. In the embodiment illustrated in FIGS. 8 and 9, outer crankshaft 436 includes an assembly of components, although one or more of outer crankshafts 430, 432, 434 and 436 may have a unitary construction. As shown in FIGS. 8 and 9, crankshaft 436 includes front and rear wheels 440 and 442. Front wheel 440 includes rearward facing journal 444 that has a tang 446 at its end. Tang 446 seats in tang receiver 448 in rear crank wheel 442 (FIG. 9). Front first driver or drive member, i.e., front spur gear 450 includes a tang 452 that seats in tang receiving opening 454 in front wheel 440, and rear first driver or driver member, i.e., rear spur gear 456 also includes a tang 458 received within its tang receiving opening (not visible in FIG. 9) in rear crank wheel 442.

[0069] Bolts 460 and 462 (FIG. 5 (only two numbered) and FIGS. 7 and 8) or other fasteners extend through the bolt holes 464 and 466 in front spur gear 450 and through aligned holes 468 and 470 in front crank wheel 440, through aligned holes 472 and 474 in rear crank wheel 442 and into hole 476 and 478 in rear spur gear 456. Threads for engaging the bolts inside the rear spur gear are not visible. Consequently, the bolts secure the front spur gear, the front and rear crank assemblies and the rear spur gear together.

[0070] Front and rear wheels 440 and 442 of each outer crankshaft, e.g. crankshaft 436, may have an oil groove 480 and 482 (FIGS. 8 and 9) for lubricating the wheels. The oil grooves may receive lubricant from oil feed 338 (FIG. 12). The oil feed may be angled for ease of machining. Alternatively, the oil feed could be straight by drilling it after drilling through arm plates 340 and 344.

[0071] Pressure from gases caused by ignition of fuel in the combustion chamber associated with rocker 376 causes rocker 376 to pivot inward (i.e., in FIG. 7, the right side of rocker 376 moves downward). Accordingly, the rocker drives link 418 against journal 444 of outer crankshaft 436, which rotates the crankshaft. The parts are dimensioned such that when the rocker reaches its innermost position, the crankshaft journal is at or near its bottom position. Continued rotation of the journal drives the rocker outward. If the rocker is in position other than being pushed by gas expansion and depending on the position of the rocker in its cycle, the crankshaft pulls or pushes the rocker.

[0072] A main crankshaft 610 (shown in FIGS. 2, 3, 5 and 13), which may be 4130 steel, provides power from the engine to power a vehicle or produce other useful work. The main crankshaft 610 may be one piece, or an assembly of separately formed pieces that are connected together. The main crankshaft 610 may include a section or sleeve 616 (FIG. 3), which has a larger diameter than intermediate diameter portions 614. Oil grooves 650 and 652 (FIG. 13) at the ends of larger diameter section 616 carries oil for lubrication. The main crankshaft 610 also includes smaller diameter flanges 612 and 618 at the crankshaft's ends. In addition, sleeve 616 includes a longitudinal keyway 632 (FIG. 13). Although FIG. 13 shows only one keyway, crankshaft 610 may include more than one keyway.

[0073] The longitudinal center of main crankshaft 610 may be hollow to transfer oil to outside the crankshaft and from one oil hole to another. For example, one or more oil distribution channels 640 (FIG. 13) may extend along the center, larger-diameter section 616 and connect with oil grooves 650 and 652. Likewise, one or more additional circumferential oil troughs 642 and 644 may extend around the outside of the main crankshaft's smaller diameter flanges 612 and 618. Oil feeds 628 and 630 may carry lubricant to the oil troughs. Flanges 612 and 618 may have keyways 634 and 636. The ends of the flanges form bolt holes 638, only one of which is visible in FIG. 13.

[0074] Referring to FIG. 12, a thrust ring 540, which may be bronze, mounts in thrust ring cavity 542 in rotor 310, and a corresponding thrust ring (not visible in FIG. 12) mounts on the other side of rotor 310. Each thrust ring has a bore 544. Main crankshaft 610 may be mounted to rotor 310 by positioning main crankshaft 610 inside cavity 542, and sliding thrust rings (e.g., thrust ring 542) over main crankshaft 610. A key 546 from each thrust ring engages keyway 640 of sleeve 616.

[0075] Main crankshaft 610 extends through ring gears 620 and 622 (broady, second drivers or drive members) and ring plates 396 and 398. The ring gears 620 and 622 may be 4140 steel. The main crankshaft 610 mounts in bores (only bore 510 is visible in FIGS. 6, 7, and 12) in the center of arm plates 340 and 342. The ring gears may be fixed against the insides of front plate 230 and rear plate 232 (FIGS. 1 and 2). For example, the ring gears may be fixed to mounting plate 662, and bolts 660 may secure the ring gears and mounting plate to the front and rear plates. The ring gears also may be fixed to other structure.

[0076] The teeth of front spur gear 450 and rear spur gear 456, which are associated with outer crankshaft 436 and rocker 376, engage the teeth on ring gears 620 and 622. Likewise, other spur gears on the other outer crankshafts, e.g., 432, 434, 436, associated with the other rockers also engage the teeth on the front or rear ring gear. Because the ring gears are stationary, spur gear rotation causes the spur gears to revolve around the ring gears. The connection of the outer crankshafts including their spur gears to rotor 310 causes the rotor to rotate about the rotor's axis of rotation. That axis coincides with the main crankshaft's axis of rotation.

[0077] In the figures, the spur gears travel around the outside of the ring gear. The ring gear could be a planetary gear with internal teeth so that the spur gears would travel around the inside of such a gear. Further, although the drawings show spur gears engaging a ring gear, the gears could be replaced with other devices such as belts, chain drives and friction drives capable of driving or being driven through their interaction.

[0078] The ratio of the number of spur gear teeth to ring gear teeth can be modified. Doing so changes the angular distance that rotor 310 travels for each rotation of the spur gears, e.g., gears 450 and 456.

[0079] Flanges 612 and 618 of main crankshaft 610 may extend through bores 244 and 246 in front and rear plates 230 and 232 (FIG. 2). Having only one flange protrude from housing 200 may be acceptable, however. The crankshaft flanges may extend through respective openings 252 and 254 of crankshaft collars 248 and 250. Fasteners (not shown) extending through openings 256 in front crankshaft collar 248 engage bores 258 in front plate 230, and corresponding fasteners secure the rear collar 250 to the rear plate. Each collar may have seals (not shown) around the inside of openings 252 and 254. A timing mark mount hole 260 (FIG. 2) also may be provided.

[0080] Front and rear plates 230 and 232 may include oil ring seal groove 238 (only shown on plate 232 in FIG. 2). Corresponding ring seals (e.g., seal 532 shown in FIGS. 2 and 19) seat in the ring seal grooves to create a seal between the front and rear rotor ring plates 396 and 398 and the insides of front and rear housing plates 230 and 232 when those plates are attached to housing body 202. The ring plate seals may include an annular shoulder 530, which faces and is in contact with the ring plates. The ring plate seals may be cast iron, silicon graphite, carbon fiber or other appropriate material. Springs (not shown) may bias the ring plate seals toward the front and rear ring plates.

[0081] Ring plate seals 532 remain stationary with respect to housing plates 230 and 232 during rotation of rotor 310. Thus, the rotor's ring plates 396 and 398 slide on the ring plate seal. The ring plate seals have a rim shoulder 534 (shown in FIG. 19). Gaskets (not shown) may also seal plates 230 and 232 to the housing body 202. Other devices or systems may be provided to prevent galvanic corrosion due to any dissimilar metals being in contact with each other.

[0082] FIGS. 16 and 17 show two alternative designs for front and rear ring plates, designated 492 and 494, respectively. An outer face 580 of front ring plate 492 includes a boss 582. The boss 582 fits into a corresponding indentation on the housing front or rear plate that would be modified from end plates 230 or 232 shown in FIG. 2. Openings such as openings 584, 586 and 588 may serve several functions. Openings 584 and 586 and corresponding holes in ring plate 494 are for fasteners (not shown) for attaching the ring plates to the rotor. Openings 590 and 592 (FIG. 17) are for spur gear clearance and support. One opening in each quadrant may mount a pivot pin for the rotor's rockers. Instead of cutouts extending completely through the ring plates, such as cutouts 484, 486, 488, and 490 shown in FIG. 3, front and rear ring plates 492 and 494 may include recesses, such as recess 590 (FIG. 17), defined in an inner wall of the respective ring plate. Spur gears 594 (FIG. 21), mount in each recess. Bores 588 and 592 (FIGS. 16 and 17) extend through respective ring plates 492 and 494 and receive hub 596 of the corresponding spur gear. A shaft would extend through the bore to connect a spur gear to the wheel of the outer crankshaft. Openings (not shown) also could be provided adjacent the spur gears for spraying lubrication onto the spur gears.

[0083] For the engine to operate, controlled amounts of air and fuel are injected through intake port 514 (FIGS. 10 and 11) as rockers, such as rocker 374 (FIG. 5), pivot about their respective pivot pins (e.g., pivot pin 380) inward. Electronic control may vary the amount of air and fuel or the air-fuel ratio. A turbocharger or supercharger could increase the volume of air (oxygen) through the intake port. As the spur gear on outer crankshaft 434 revolves about front ring gear 620 (and a corresponding spur gear revolves about rear ring gear 622), the outer crankshaft rotates. The outer crankshaft's connection through a link to rocker 374 pivots the rocker inward. The inward pivoting causes a pressure decrease in chamber 366 (marked "Intake" chamber in FIG. 5).

[0084] After chamber 366 receives a predetermined amount of air and fuel, rotor 310 rotation carries chamber 366 past intake port 514 (FIGS. 10 and 11). Further rotation of the rotor 310 causes outer crankshaft 434 to begin pivoting rocker 374 outward. Because the drawings are not animated and the components remain stationary, consider that chamber 366 has moved to the position where chamber 360 had been in the drawings and that the reference numerals for the parts that had been there now are used. As rocker (now 376) pivots outward, the decrease in volume in chamber 360 causes a corresponding pressure increase (compression) of the air-fuel mixture in the chamber above the rocker.

[0085] Referring again to FIG. 8, the top surface of the rockers, e.g., rocker 376, may be coated. In the embodiment illustrated in FIG. 8, the top surface of rocker 376 has a central combustion region 402 surrounded by a squish zone 408. In a piston engine, a squish zone is a narrow section of a combustion chamber in which the air-fuel mixture is more compressed than in the rest of the chamber. A squish zone helps direct the flow of a fresh air-fuel mixture and to improve scavenging (i.e., pushing exhausted gas out of the cylinder). Here, squish zone 408 is a raised surface extending outward from surface 402, and conforms to inner wall 204 of housing body 202. This raised surface creates higher pressures around the extended edges of combustion surface 402.

[0086] Squish zone 408 may create turbulence by compressing the air-fuel mixture in the zone as the mixture reaches full compression over central combustion region 402. This may allow more complete burning of the gaseous mixture to decrease emissions. The squish zone also may improve exhausting of the remaining burnt gases. The surface of the squish zone may be 0.010 in. to 0.080 in. (0.25 mm to 2 mm) (metric equivalents are approximations) above combustion surface 402 with 0.020 in. to 0.060 in. (0.5 mm to 1.5 mm) possibly preferred.

[0087] Referring to FIGS. 1 and 4, a spark plug 520 extends through a mount 522 defined in housing body 202, and toward chamber 360 such that a spark from spark plug 520 can ignite the compressed air-fuel mixture. High-pressure, direct injectors may be installed into housing 202 in close proximity to the spark plug 520 for gasoline direct injection. The hot end of the spark plug may terminate in a recess 524 in inner wall 204 of housing body 202 (shown in FIG. 10). The recess is shown as cylindrical, but could be sized and shaped to improve combustion. Although the illustrated embodiment is shown with a single spark plug, rotary engine 100 may include two or more sparks plugs for each combustion chamber. In other embodiments, rotary engine may operate based on a diesel cycle at higher pressures and without a spark plug. Those higher pressures may require different materials or different dimensions for the rotary engine's components.

[0088] Spark plug 520 fires at a predetermined time for proper engine timing. The ignition of the fuel in the presence of air in chamber 360 causes combustion and creates a substantial increase in pressure in the chamber. The pressure from the combustion applies a force on rocker 376, moving rocker 376 to its inward position.

[0089] Through the connection of outer crankshaft tang 436 with tang receiver 448, the inward movement of rocker 376 rotates outer crankshaft 442. As a result, spur gears 450 and 456 rotate and travel along the outside of ring gears 620 and 622 (FIGS. 3 and 5). This, in turn, causes rotor 310 to rotate.

[0090] Continued rotation of rotor 310 positions the chamber to the position of chamber 364 in FIG. 5. During this rotor rotation, the spur gears associated with the rocker (now rocker 372) act on the link between the outer crankshaft and the rocker to pivot the rocker outward. The outward pivoting pushes exhaust gases through exhaust port 516 (FIGS. 2, 10 and 11). This cycle is repeated as rotor 310 continues to rotate.

[0091] During each revolution of rotor 310, each of the four chambers sequence through four cycles: intake, compression, power (i.e., combustion) and exhaust. The timing of the intake, compression, combustion and exhaust cycles can be modified by modifying the offset pivot of the rocker link, e.g., link 418 relative to its outer crankshaft 436 and to its rocker 376 (FIG. 8) and the position of its pivot pin 380. Additionally or alternatively, the timing of the intake and/or exhaust may be altered by modifying the configuration (e.g., shape) and/or radial position of intake port 514 and/or exhaust port 516.

[0092] Because the rocker's pivot is stationary, the pivot also may create an arc-shaped offset angle. For example, the rockers can have longer power and intake cycles than their compression and exhaust cycles. Those cycles may be as follows: intake=100.degree., compression=80.degree., combustion=100.degree. and exhaust=80.degree.. This overlap could allow each combustion cycle to fire 20.degree. before the previous chamber has finished its power cycle. This overlap function may allow smoother transitions between power cycles.

[0093] In addition, the intake and exhaust ports 514 and 516 (FIGS. 10 and 11) may overlap so that new air and fuel enter the combustion chamber through the intake port as it opens and before the exhaust port is completely closed-off. This may allow a small rush of new air-fuel mixture to push out the remaining exhaust gases drawing in a completely new charge of fuel and air. The degree of overlap of the intake and exhaust ports 514 and 516 may be between about 0.degree. to about 24.degree., more suitably between about 1.degree. and about 20.degree., and even more suitably, about 8.degree..

[0094] In the illustrated embodiment, only the outer crankshaft connected to the rocker within the combustion chamber receives power directly from combustion-caused pressure acting on the rocker. Through rotation of that outer crankshaft's spur gear acting on ring gears 620 and 622, rotor 310 rotates. At the same time, continued rotation of the rotor causes the spur gears of the other three outer crankshafts to rotate, which, in turn pivots the rockers associated with those crankshafts inward or outward. As each rocker and its corresponding spur gear move to the power/combustion position where the air-fuel mixture ignites, expanding gases drive the rocker inward. Consequently, that set of spur gears become the driving gears, and the other spur gears become driven gears.

[0095] When the rotor assembly 300 is assembled, the rear face of front ring plate 396 and the front face of rear ring plate 398 engage respective sides of rotor 310. Each side of the rotor 310 may have a sealing groove, such as sealing groove 530 shown in FIGS. 5-7, that runs along the periphery of the arms. A rotor seal cord (not shown) may be installed in the sealing grooves on both sides of rotor 310 to form a seal between the arms 312, 314, 316, and 318, and ring plates 396 and 398.

[0096] As shown in FIG. 1, when rotary engine 100 is assembled, main crankshaft 610 extends through collar 248. If the rotary engine is used on a vehicle, the main crankshaft 610 may be connected to the rest of the vehicle's drive train, e.g., a transmission, a clutch or other components. For non-vehicle uses, such as pumps and compressors, the crankshaft 610 connects to the driven device. The main crankshaft 610 also could be driven if the device is used as a compressor or pump, such as compressor 800 described below with reference to FIG. 20. The main crankshaft 610 also may extend out either side or both sides of the housing.

[0097] Various components of the rotary engine may have channels and openings, such as openings 346 and 348 (FIGS. 6, 7, and 12), for coolant and lubricant. Such channels and openings may vary with different engine sizes and designs. The arms also may have oil jets, e.g., jet 338 (FIG. 12) for providing lubrication in the chambers. These oil jets may be pressure or movement activated, allowing oil to pass only when desired. Other physically activated (pressure or movement) oil jets may be placed on various component parts, such as the front and rear plates 230 and 232 (FIG. 2) for controlled oiling of moving parts. Components and parts may have bushings or bearings (not shown) where needed for reducing friction, metal to metal contact protection, or holding desired tolerance specifications. Oil vacuum ports on the front and rear plates 230 and 232 (FIG. 2) may be placed at the lowest available gravitational oil collection area, depending on the physical mounting position of the engine, to extract oil away from moving parts. Parts also may have cutouts to decrease weight or provide better heat dissipation.

[0098] Referring to FIG. 4, rotary engine 100 is illustrated in a vehicle environment. An air intake system 110 may include an air filter 112 on a throttle body 114, which connects to an intake manifold 116. Air from the intake system flows into intake chamber 366 (FIG. 5). A fuel injector 126 is positioned near the intake chamber. The engine may be designed to burn different fuels, e.g., gasoline, ethanol, CNG, LNG, propane, or hydrogen. The fuel injector of such an engine could have separate outlets 128 and 130 for different fuels. Exhaust from chamber 364 (FIG. 5) passes into an exhaust header 118 and into the remainder of the exhaust system. A starter motor 120, an alternator 122, and an electronic control unit (ECU) 124 are also attached to housing 200.

[0099] The size of the engine compartment and the position of the rotary engine in the engine compartment may affect the various components' locations insofar as they must fit in the compartment and may need to be accessible for service.

[0100] Belts or other connectors (not shown) may drive the alternator and other devices from engine power.

[0101] FIG. 14 is a front view of an exemplary two-chambered rotor 550 suitable for use in a rotary engine. Rotor 550 may rotate one or more times per each power engine power stroke, depending on the desired usage of rotor 550. The rotor 550 has two arms 552 and 554 that may be shaped as shown in FIG. 14. The arms form two opposite chambers 556 and 558. Rockers 560 and 562 mount on respective pins 564 and 566. Outer crankshafts (not shown in FIG. 14) connect to rockers through linkage similar to that shown in FIG. 8. Each crankshaft may have spur gears (not shown in FIG. 14) at the outer crankshaft end that protrudes through bores 568 and 570 from the rotor. A main crankshaft (not shown in FIG. 14) extends through center bore 572. Stationary ring gears (not shown in FIG. 14) mount to stationary housing structure.

[0102] In one position in FIG. 14, the air-fuel mixture is injected or otherwise enters one of the chambers, e.g., chamber 556. As rotor 550 rotates, rocker 560 pivots outward to compress the air-fuel mixture until, at or close to full compression, a spark ignites the air and fuel. Depending on the desired usage of rotor 550, rotor 550 may rotate with or without exhausting the exhaust gases until the rotor returns to its initial position, i.e., where chamber 556 is in FIG. 14. Valves (not shown) may control intake and exhaust from chambers 556 and 558. One or more valves open to allow the air-fuel mixture to enter chamber 556, and then one or more different valves open to allow the exhaust gases to enter the exhaust system.

[0103] The rotary engine that has been described is a four-stroke engine, intake, compression, combustion and exhaust. In a four-stroke piston engine, those strokes occur every two rotations of the main crankshaft. Two-stroke piston engines complete a cycle in two movements of the piston, in and out. The rotary engine could be modified into a two-stroke engine. Two- and four-stroke designs have advantages and drawbacks relative to each other.

[0104] A typical use of internal combustion engines is in vehicles. Just as piston engines come in different sizes, compressions, power rating and other factors for different vehicles, the rotary engine's specifications can vary. Insofar as the rotary engine powers generators, pumps, machinery or other devices, the engine may have different designs. Some might require higher speed but less low-speed torque. Other application may require high torque at low speed. Some application may require constant output over long periods. Adjusting the combustion chamber volume, the size and pivoting angle of the rockers and other factors of the rotary engine may be modified to satisfy an engine's requirements.

[0105] At least two ways allow matching output power to power needs. The first is to have larger combustion chambers with larger rockers. Increasing the diameter of rotor 310 may allow the rockers to pivot through a larger angle to increase displacement. Likewise, increasing the width of the rotor also increases the displacement of each chamber. Optimizing performance may require balancing the effect of increasing the rotor's diameter and width. For example, increasing dimensions weight of all components and may affect other engine components or engine symmetry.

[0106] Stacking two or more rotor assemblies or power modules along the main crankshaft also could combine the modules' power output. In addition, combinations of different sized rotor assemblies or power modules can be assembled into one unit.

[0107] FIG. 15 shows a duel unit rotary engine 700 comprising a front unit 702 and rear unit 704. The front unit is bounded by front plate 706 and center plate 710, and the rear unit is bounded by rear plate 708 and center plate 710. In FIG. 15, the locations where combustion occurs are on the same side of the housing, but they could mount 180.degree. apart. Likewise, with more rotors for one engine, the location where combustion occurs could be spaced evenly around each housing, e.g., 120.degree. apart for three rotors and 90.degree. for four rotors.

[0108] Though the configuration just described are internal combustion engines, rotary engine 100 may also be utilized in a compressor. FIG. 20, for example, illustrates a compressor 800 including a housing body 802. Compressors may be free-standing. Therefore, the compressor may include base 804. The housing body 802 has a cylindrical opening 806 configured to receive a power module or rotor assembly, such as rotor assembly 300 (shown in FIG. 2). Front and rear housing plates (not shown; similar to plates 230 and 232 in FIG. 2) cover the rotor assembly and cylindrical opening. Seals 810 and 812 may seal the housing plates to the housing body, and fasteners (not shown) extending through openings in the housing plates may attach to bores 808 in the housing body. A main crankshaft of the rotor assembly (such as main crankshaft 610) extends through the housing plates and connects to a separate motor or engine. When the device is used as a compressor, the main crankshaft is driven instead of providing the motive force.

[0109] Housing body 802 includes one or more inlets 820 and 824 and one or more outlets 826 and 828. These inlets and outlets could be used for high pressures such as for hydraulic pressurization. Valves may be provided for any inlets or outlets, and their construction and operation may depend on the fluid volume and pressure. Various bores such as bores 830, 832, 836 and 838 may be provided for fastening related devices, such as inlets and outlets for lubrication.

[0110] Rotor rotation causes the rockers to pivot in an out. The inlets are positioned to receive air, other gas or liquid (i.e., fluid) either from the atmosphere in the case of air or from a source of fluid. The fluid flows into one of the rotor chambers as the rocker pivots inward to lower the pressure. When the rotor rotates away from the inlet, the rocker pivots outward to compress the fluid and force it through an outlet. With a four-chambered rotor, the rotor rotates to another inlet, draws fluid into the chamber and then compresses the fluid as the rotor moves adjacent another outlet.

[0111] Four strokes are not necessary. Thus, pressurized fluid can flow out an outlet at all compression strokes (pivoting outward of the rocker). Accordingly, the rotor could have two, four, six or more chambers with a corresponding number of rockers and outer crankshafts subject to space limitations.

[0112] FIG. 22, for example, illustrates a rotor 910 with eight chambers. Rotor 910 may be particularly useful as a heavy-duty diesel unit. Rotor 910 includes eight arms 912, 914, 916, 918, 920, 922, 924 and 926. Pairs of adjacent partially define eight chambers, such as chamber 930 between arms 914 and 916 and chamber 923 between arms 916 and 918. The inner cylindrical wall (not shown) of a housing in which rotor 910 is received defines the outside of each chamber. A rocker, such as rockers 934 and 936, is pivotally mounted near the distal end of each arm 912, 914, 916, 918, 920, 922, 924 and 926. Rockers are configured to pivot inward and outward of their respective chambers, such as chamber 930. Rocker 934 is illustrated in an inward position in FIG. 22, and rocker 936 is illustrated in an outer position in FIG. 22.

[0113] Rotor 910 is formed of front plate 940 and a corresponding rear plate, which is not visible in FIG. 22. Bores, such as bores 942 and 944, extend through the rotor's front plate, and corresponding and aligned bores (not shown) extend through the rear plate. Properly sized wheels (not shown in FIG. 22) mount in the bores, and spur gears (not shown in FIG. 22) mount to the wheels and extend out of the bores. The spur gears engage a ring gear mounted on a main crankshaft extending through central bore 946, and rotate as the rotor 910 rotates about its axis. Linkages between the wheels and the rockers cause the rockers to pivot in and out of their respective chambers as the rotor rotates. When fuel ignites in the chamber that is then the power chamber, force from the expanding gas on the rocker rotates the wheels and spur gear. That rotation acts on the ring gear to rotate the rotor.

[0114] The rotor may have additional bores such as bores 950 and 952 to decrease weight. The bores also may carry lubricant.

[0115] The outside of each arm that contacts or is close to contact with the cylindrical wall of the housing may have two grooves, e.g., grooves 958 and 960, which receive seals (not shown). Other seals for sealing the chambers and the rotor itself are not shown.

[0116] In the eight-chamber version, the air-fuel mixture ignites simultaneously in two chambers on opposite sides of the housing. Thus, during each rotor rotation, each chamber completes eight cycles (intake, compression, power, exhaust, intake, compression, power, and exhaust). Engines with 12, 16 or more chambers per rotor are contemplated. They may be particularly useful for large and heavy equipment such as earth movers, mining dump trucks, and cranes.

[0117] FIG. 23 is an exploded view of an exemplary housing 2300 suitable for use in rotary engine 100. Housing 2300 is substantially similar to housing 200 described above with reference to FIGS. 1-2, except housing 2300 includes a housing body 2302 and a sleeve 2304 received within housing body 2302. Sleeve 2304 is sized and shaped to interface statically, via a tight tolerance press or clamp, with housing body 2302. Sleeve 2304 is configured to receive a rotor assembly, such as rotor assembly 300, and act as an intermediary part between housing body 2302 and rotor assembly 300.

[0118] Housing body 2302 and sleeve 2304 each include respective inlets or intake ports 2306, 2308, outlets or exhaust ports 2310, 2312, and spark plug mounts 2314, 2316. When sleeve 2304 is coupled to housing body 2302, inlet 2308, outlet 2312, and spark plug mount 2316 of sleeve 2304 align with inlet 2306, outlet 2310, and spark plug mount 2314 of housing body 2302, respectively.

[0119] FIG. 24 is a cross-sectional view of an exemplary rotor 2400 suitable for use with housing 200 and rotor assembly 300 (both shown in FIG. 2). Although rotor 2400 is described with reference to housing 200 shown in FIG. 2, it is understood that rotor 2400 may be utilized in other rotary engine housings, such as housing 2300 shown in FIG. 23. Rotor 2400 is substantially similar to rotor 310 described above with reference to FIGS. 3-7 and 12, except rotor 2400 includes a counterbalanced seal assembly 2402 configured to improve performance of rotary engine 100 and increase the service life of a corresponding crossover seal within rotary engine 100.

[0120] As shown in FIG. 24, rotor 2400 includes a plurality of arms 2404 extending radially outward from a central portion or hub 2406. Each arm 2404 extends arcuately from hub 2406 to a respective distal end 2408 disposed for sliding engagement with inner wall or surface 204 of housing 200 (FIGS. 1-2). Rotor 2400 may be formed of the same materials as rotor 310 described above with reference to FIGS. 3-7 and 12. Further, rotor 2400 may be formed of two plates similar to rotor 310.

[0121] Each arm 2404 has a bore 2410 defined therein that extends axially through rotor 2400. Each bore 2410 is sized and shaped to receive an outer crankshaft, such as crankshaft 436 (shown in FIGS. 5-9), therein. Each arm 2404 also defines a rounded portion 2412 configured to receive a portion of a rocker, such as rocker 376 (shown in FIG. 8).

[0122] Distal end 2408 of each arm 2404 includes an outer surface 2414 shaped complementary to inner wall 204 of housing 200. Distal end 2408, specifically, outer surface 2414, of each arm 2404 is disposed for sliding engagement with inner wall 204 of housing body 202. A seal channel 2416 is defined in each arm 2404, and extends radially inward from outer surface 2414. In the embodiment shown in FIGS. 24 and 25, a pair of cavities 2418 is also defined within each arm 2404. Each cavity 2418 extends circumferentially from opposite sides of seal channel 2416. Seal channel 2416 and cavities 2418 are configured to receive a counterbalanced seal assembly 2402, as described in more detail below. Only one counterbalanced seal assembly 2402 is shown in FIG. 24, although it is understood that each arm 2404 may include a counterbalanced seal assembly 2402. In other embodiments, cavities 2418 may be omitted from arms 2404 (see, e.g., FIGS. 30 and 31).

[0123] Rotor 2400 is configured to be assembled as part of a rotor assembly, such as rotor assembly 300, and mounted for rotation within an engine housing, such as housing 200 (FIGS. 1-2). When rotor 2400 is assembled within rotor assembly 300 and mounted within housing 200, rotor 2400 is configured to operate in substantially the same manner as rotor 310 described above with reference to FIGS. 3-7 and 12. Specifically, each arm 2404 is configured to be pivotally coupled to a rocker, such as rocker 376 (shown in FIG. 8), which is operably coupled to an outer crankshaft, such as crankshaft 436 (shown in FIGS. 5-9), received within bores 2410. The outer crankshafts are configured to engage second drivers or drive members (e.g., ring gears 620 and 622) mounted to housing 200. The inward and outward pivoting of rockers causes the outer crankshafts to rotate, and the outer crankshafts engage the second drive members to rotate rotor 2400. An output member, such as main crankshaft 610, is operably coupled to rotor 2400, and rotates upon rotation of rotor 2400.

[0124] FIG. 25 is an enlarged view of distal end 2408 of arm 2404, illustrating details of seal channel 2416, cavities 2418, and counterbalanced seal assembly 2402. As shown in FIG. 25, counterbalanced seal assembly 2402 includes a crossover or apex seal 2420 and a counterweight mechanism 2422.

[0125] FIG. 26 is a side view of seal 2420, and FIG. 27 is a perspective view of a portion of seal 2420. In the illustrated embodiment, seal 2420 has a generally T-shaped cross-section, and includes a head 2424 and a stem 2426 extending generally perpendicular from head 2424. Head 2424 defines an outer surface 2428 configured to sealingly engage inner wall 204 of housing body 202. Stem 2426 defines a pair of grooves 2430 extending inward from laterally opposite sides of stem 2426.

[0126] In the illustrated embodiment, head 2424 extends a width or arc length 2432 in a lateral direction (i.e., a circumferential direction of rotor 2400) that is greater than the circumferential width of intake port 514 and the circumferential width of exhaust port 516 (both shown in FIG. 11). As used with reference to intake and exhaust ports 514, 516, the term circumferential width refers to the width of the respective port as measured in the circumferential direction of housing body 202. Seal 2420 thereby maintains a constant seal with inner wall 204, and inhibits fluid flow around seal 2420 that might otherwise occur via intake and exhaust ports 514, 516.

[0127] In the illustrated embodiment, seal 2420 includes two separate pieces capable of moving or sliding in a radial direction independently of one another. Specifically, seal 2420 includes a first sealing member 2434 and a second sealing member 2436. First sealing member 2434 and second sealing member 2436 are positioned adjacent one another in seal channel 2416, and abut one another along respective engaging surfaces 2438, 2440. In the illustrated embodiment, first sealing member 2434 and second sealing member 2436 are not physically linked, adhered, or otherwise connected to one another, and are free to move or slide past one another in a radial direction. In other embodiments, seal 2420 may have a unitary construction--i.e., seal 2420 may be formed from a single piece of material. Seal 2420 may be constructed from a variety of suitable materials, such as ductile iron.

[0128] FIG. 28 is a perspective view of counterweight mechanism 2422. In the illustrated embodiment, counterweight mechanism 2422 includes a counterweight 2442 and a lever 2444 extending away from counterweight 2442. Counterweight 2442 has a generally cylindrical shape, and is sized to be received within one of cavities 2418. In other embodiments, counterweight 2442 may be shaped other than generally cylindrical. Lever 2444 extends outward from counterweight 2442, and is sized and shaped to be received within one of grooves 2430 defined by stem 2426. Together, counterweight 2442 and lever 2444 define a pair of longitudinally or axially extending grooves 2446. As described in more detail herein, grooves 2446 are configured to cooperate with a portion of the arms of rotor 2400, such as arm 2404, to cause counterweight mechanism 2422 to pivot in response to rotation of rotor 2400. Counterweight mechanism 2422 is suitably constructed from a relatively high density material, including, but not limited to, steel, iron, lead, and combinations thereof.

[0129] Referring again to FIG. 25, arm 2404 includes a fulcrum 2448 configured to pivotally engage counterweight mechanism 2422 at a pivot point. In the illustrated embodiment, fulcrum 2448 includes a support 2450 extending radially inward from distal end 2408 of arm 2404. Support 2450 is disposed between one of cavities 2418 and seal channel 2416, and partially defines seal channel 2416 and one of cavities 2418.

[0130] Seal channel 2416 extends radially inward from outer surface 2414, and is sized and shaped to receive seal 2420. In the illustrated embodiment, seal channel 2416 extends from outer surface 2414 to a radial depth that is greater than a radial length of seal 2420. Seal channel 2416 allows radial displacement of seal 2420, for example, as a result of centrifugal forces imparted on seal 2420 from rotation of rotor 2400. In the illustrated embodiment, seal channel 2416 has a T-shaped cross-section corresponding to the T-shaped cross-section of seal 2420, although seal channel 2416 may have any suitable configuration that enables counterbalanced seal assembly 2402 to function as described herein. Each cavity 2418 is defined within arm 2404, and extends axially through arm 2404. Cavities 2418 extend circumferentially into arm 2404 from opposite sides of seal channel 2416. Each cavity 2418 is sized and shaped to receive counterweight 2442.

[0131] In operation, seal 2420 is configured to sealingly engage inner wall 204 of housing body 202, and thereby inhibit fluid flow between adjacent chambers defined by arm 2404. Seal 2420 is configured to slidingly engage inner wall 204 of housing body 202 as rotor 2400 rotates, and maintain a constant seal with inner wall 204. Seal 2420 exerts a contact pressure on inner wall 204 to maintain the seal between adjacent chambers. As the rotational speed of rotor 2400 increases, centrifugal forces acting on seal 2420 increase, and cause the contact pressure between seal 2420 and inner wall 204 to increase. Such contact pressure, if not controlled, can cause seal 2420 to wear quickly, and reduce the service lifetime of seal 2420.

[0132] Counterweight mechanism 2422 is configured to control the radial displacement of seal 2420 resulting from rotation of rotor 2400, and control the contact pressure exerted by seal 2420 on inner wall 204 resulting from rotation of rotor 2400. Specifically, the center of gravity of counterweight mechanism 2422 is offset towards counterweight 2442. As a result, centrifugal forces acting on counterweight mechanism 2422 cause counterweight mechanism 2422 to pivot about a pivot point defined by fulcrum 2448. The engagement between lever 2444 and seal 2420 along groove 2430 limits the radial outward displacement of seal 2420 resulting from rotation of rotor 2400, thereby limiting the contact pressure between seal 2420 and inner wall 204.

[0133] In the illustrated embodiment, counterbalanced seal assembly 2402 includes two counterweight mechanisms 2422 disposed on laterally opposite sides of seal 2420. Each counterweight mechanism 2422 engages one of forward and rear sealing members 2434, 2436 (FIG. 26) within groove 2430. The two counterweight mechanisms 2422 enable independent radial movement of first sealing member 2434 and second sealing member 2436, thereby enabling a contact-pressure differential between first sealing member 2434 and second sealing member 2436. In other embodiments, counterbalanced seal assembly 2402 may include only a single counterweight mechanism.

[0134] As noted above, lever 2444 is operatively coupled to seal 2420 via an engagement between lever 2444 and groove 2430 defined in seal 2420. In other embodiments, lever 2444 may be operatively coupled to seal 2420 by any suitable means that enables counterbalanced seal assembly 2402 to function as described herein. In one embodiment, for example, counterweight mechanism 2422 is hingedly coupled to seal 2420 by one or more pins (see, e.g., FIGS. 35 and 36).

[0135] FIG. 29 is a partial cross-sectional view of a rotor arm 2900 illustrating another embodiment of a counterbalanced seal assembly 2902 suitable for use with rotor 2400 (FIGS. 24 and 25). Rotor arm 2900 and counterbalanced seal assembly 2902 are substantially identical to rotor arm 2404 and counterbalanced seal assembly 2402 described with reference to FIGS. 24-28, except counterbalanced seal assembly 2902 includes a control mechanism 2904. As such, components illustrated in FIG. 29 identical to components shown in FIGS. 24-28 are identified with the same reference numbers.

[0136] Control mechanism 2904 is configured to selectively control the contact pressure between seal 2420 and inner wall 204 of housing body 202 by exerting a variable radial force on seal 2420. In the illustrated embodiment, control mechanism 2904 is operably coupled to seal 2420 via counterweight mechanism 2422, and controls the contact pressure between seal 2420 and inner wall 204 by exerting a variable radial force on counterweight 2442. By exerting a variable radial force on counterweight 2442, control mechanism 2904 facilitates controlling the radial displacement of counterweight 2442 within cavity 2418, and thereby enables control of the radial displacement of seal 2420. In other embodiments, control mechanism 2904 may be operably coupled to seal 2420 by an intermediate linking member other than counterweight mechanism 2422. In some embodiments, for example, control mechanism 2904 is coupled to seal 2420 by a linking arm, such as lever 2444. In other words, counterweight 2442 may be omitted from counterbalanced seal assembly 2902, and control mechanism may be coupled to seal 2420 via lever 2444.

[0137] Control mechanism 2904 may include any suitable mechanism configured to exert a variable radial force on seal 2420. In some embodiments, control mechanism 2904 includes an actuator 2906 operably coupled to seal 2420 either directly or indirectly by one or more intermediate linking members, such as counterweight mechanism 2422. Although actuator 2906 is illustrated within cavity 2418 proximate counterweight 2442, actuator 2906 may be disposed remote from counterweight 2442, such as within hub 2406 of rotor 2400 (FIG. 25) or within housing body 202 (FIG. 2).

[0138] Actuator 2906 may be actuable by a variety of suitable means, including, for example, mechanical, hydraulic, pneumatic, magnetic, and combinations thereof. In some embodiments, for example, actuator 2906 may include a pneumatic actuator operably coupled to seal 2420 via counterweight mechanism 2422. In another embodiment, actuator 2906 may include a magnet or electromagnet configured to magnetically interact with counterweight 2442 to control the radial displacement of counterweight 2442 within cavity 2418.

[0139] In other embodiments, actuator 2906 may be actuable in response to one or more environmental conditions within rotary engine 100. In the illustrated embodiment, for example, actuator 2906 includes a bimetallic strip (broadly, a multi-layer metallic strip) operably coupled to counterweight 2442, and configured to bend outward and inward in a radial direction in response to temperature changes within the rotary engine. The actuator 2906 is thereby configured to exert a variable radial force on counterweight 2442 based on a temperature within rotary engine 100. The layers of the bimetallic strip may be constructed from any suitable material that enables the bimetallic strip to exert a variable radial force on counterweight 2442 in response to temperature changes within rotary engine 100. In one embodiment, for example, one layer is constructed from steel and the other layer is constructed from copper or a copper alloy, such as brass. In the illustrated embodiment, control mechanism 2904 includes two bimetallic strips, although control mechanism 2904 may include any suitable number of bimetallic strips that enables control mechanism 2904 to function as described herein, such as a single bimetallic strip.

[0140] In some embodiments, actuator 2906 may be operably coupled to and controlled by a computing device, such as ECU 124 (shown in FIG. 4), to selectively control the contact pressure between seal 2420 and inner wall 204 of housing body 202. For example, ECU 124 may be programmed to vary the radial force applied by actuator 2906 to seal 2420 at specified times and/or rotational positions during a single stroke or revolution of rotor 2400. The ECU 124 may be programmed to vary the radial force applied by actuator 2906 to seal 2420 based upon at least one of a rotational position of seal 2420, a rotational position of rotor 2400, a rotational position of main crankshaft 610 (shown in FIGS. 1-3), and combinations thereof. Control mechanism 2904 can thereby provide precise control of the contact pressure between seal 2420 and inner wall 204 at various times during a single revolution of rotor 2400.

[0141] FIG. 30 is partial perspective view of a rotor arm 3000 illustrating another embodiment of a counterbalanced seal assembly 3002 suitable for use in a rotary device, such as rotary engine 100 (FIGS. 1 and 2) and compressor 800 (FIG. 20). FIG. 31 is a partial perspective view of rotor arm 3000 illustrating counterbalanced seal assembly 3002 removed from rotor arm 3000. As described in more detail herein, the configuration of counterbalanced seal assembly 3002 facilitates installation, removal, and replacement of counterbalanced seal assembly 3002 and the components thereof.

[0142] Rotor arm 3000 extends radially outward from the central portion or hub of a rotor, such as rotor 2400 (FIGS. 24 and 25), to a distal end 3004 of rotor arm 3000. Rotor arm 3000 may include a bore (not shown) similar to bore 2410 (FIG. 24) for receiving an outer crankshaft, such as crankshaft 436 (FIGS. 5-9). Rotor arm 3000 defines a rounded portion 3006 configured to receive a portion of a rocker, such as rocker 376 (shown in FIG. 8).

[0143] Distal end 3004 of rotor arm 3000 includes an outer surface 3008 shaped complementary to the inner wall or surface of a rotary device housing, such as housing 200 (FIGS. 1 and 2) or housing 2300 (FIG. 23). Distal end 3004 is configured for sliding engagement with the inner wall or surface of a rotary device housing, such as housing 200 (FIGS. 1 and 2) or housing 2300 (FIG. 23).

[0144] As shown in FIG. 31, rotor arm 3000 includes a pair of opposing interior side surfaces 3010, 3012, a radial inner surface 3014 extending between interior side surfaces 3010, 3012, and a pair of ledges 3016 each extending outward from a respective side surface 3010, 3012. Side surfaces 3010, 3012, radial inner surface 3014, and ledges 3016 define a seal assembly channel 3018 in rotor arm 3000. Seal assembly channel 3018 extends radially inward from outer surface 3008, and extends axially through rotor arm 3000 such that counterbalanced seal assembly 3002 can be inserted or removed from either side of rotor arm 3000. Seal assembly channel 3018 is configured to receive counterbalanced seal assembly 3002. In particular, counterbalanced seal assembly 3002 is configured to slide in and out of the seal assembly channel 3018 in an axial or longitudinal direction, indicated by arrow 3020 in FIG. 31, to facilitate installation, removal, and replacement of the entire assembly. Axial direction 3020 is parallel to the axis about which rotor arm 3000 rotates during operation. As shown in FIGS. 30 and 31, rotor arm does not include cavities 2418 (FIG. 25) because all components of counterbalanced seal assembly 3002 are received within seal assembly channel 3018. That is, seal assembly channel 3018 is sized and shaped to receive each element of counterbalanced seal assembly 3002.

[0145] FIG. 32 is a partially exploded view of counterbalanced seal assembly 3002. As shown in FIG. 32, counterbalanced seal assembly 3002 includes a crossover or apex seal 3022, a base 3024, and a plurality of counterweight mechanisms 3026.

[0146] In the illustrated embodiment, seal 3022 has a generally rectangular cross-section, and includes a body 3028 and a pair of lips 3030 extending transversely outward from opposite sides of body 3028. Only one of lips 3030 is visible in FIG. 32. Body 3028 extends in axial direction 3020 from a first end 3032 of seal 3022 to a second end 3034 of seal 3022. Body 3028 defines a radial inner surface 3036 and a radial outer surface 3038. In operation, radial outer surface 3038 sealingly engages the inner wall of a rotary device housing, such as housing 200 (FIGS. 1 and 2) or housing 2300 (FIG. 23), to inhibit fluid flow between adjacent chambers of a rotary device, such as chambers 360, 362, 364, and 366 (FIG. 5).

[0147] Additionally, body 3028 extends beyond rotor arm 3000 in axial direction 3020. More specifically, body 3028 has a length in axial direction 3020 that is greater than a length of seal assembly channel 3018 in axial direction 3020. First end 3032 and second end 3034 of seal 3022 are thereby configured to sealingly engage a face plate of a rotary device, such as front and rear plates 230, 232 of housing 200 or ring plates 396, 398 (all shown in FIG. 2), to inhibit fluid flow around first end 3032 and second end 3034 of seal 3022.

[0148] A groove 3040 is defined along radial inner surface 3036 of body 3028. Groove 3040 extends axially from first end 3032 of seal 3022 to second end 3034 of seal 3022. Groove 3040 is configured to cooperate with base 3024 to maintain alignment of seal 3022 within counterbalanced seal assembly 3002, as described in more detail herein.

[0149] Each lip 3030 extends transversely outward from a respective side of seal 3022. Each lip 3030 is configured to be slidably received between at least one counterweight mechanism 3026 and base 3024. As shown in FIG. 32, each lip 3030 has a length in axial direction 3020 less than the length of body 3028 in axial direction 3020. In particular, each lip 3030 has substantially the same length in axial direction 3020 as seal assembly channel 3018 and base 3024. In operation, centrifugal forces imparted on seal 3022 from rotation of the rotor in which counterbalanced seal assembly 3002 is installed urge seal 3022 in a radially outward direction. The engagement between lips 3030 and counterweight mechanism 3026 retains seal 3022 within rotor arm 3000, and further controls the radial displacement of seal 3022, as described in more detail below.

[0150] In the illustrated embodiment, seal 3022 has a unitary construction. That is, seal 3022 is formed from a single piece of material, such as ductile iron. In other embodiments, seal 3022 may have a modular construction. That is, seal 3022 may include multiple sealing members similar to seal 2420 (FIGS. 25-27).

[0151] Base 3024 includes a pair of opposing sidewalls 3042, 3044 and a radial inner wall 3046 extending between and interconnecting sidewalls 3042, 3044. When counterbalanced seal assembly 3002 is disposed within seal assembly channel 3018, each sidewall 3042, 3044 is positioned adjacent to an interior side surface 3010, 3012 of rotor arm 3000, and extends from radial inner surface 3014 of rotor arm 3000 to a respective ledge 3016. Radial inner wall 3046 is positioned adjacent radial inner surface 3014 of rotor arm 3000. Base 3024 is sized and shaped complementary to seal assembly channel 3018 such that sidewalls 3042, 3044 and radial inner wall 3046 are flush with interior side surfaces 3010, 3012 and radial inner surface 3014, respectively. The configuration of base 3024 thereby facilitates sliding counterbalanced seal assembly 3002 in axial direction 3020 to install, remove, and replace counterbalanced seal assembly 3002.

[0152] Sidewalls 3042, 3044 and radial inner wall 3046 define a seal channel 3048 configured to receive seal 3022. Seal channel 3048 has a generally rectangular cross-sectional shape corresponding to the cross-sectional shape of seal 3022, although seal channel 3048 and seal 3022 may have any suitable configuration that enables counterbalanced seal assembly 3002 to function as described herein.

[0153] As shown in FIG. 32, base 3024 also includes a plurality of fulcrums 3050. Each fulcrum 3050 is configured to pivotally engage a counterweight mechanism 3026 along a radially inward surface of fulcrum 3050. Each fulcrum 3050 is coupled to one of sidewalls 3042, 3044. The illustrated embodiment includes four fulcrums 3050, each fulcrum 3050 corresponding to one counterweight mechanism 3026. Two fulcrums 3050 are coupled to each sidewall 3042, 3044 of base 3024 in the illustrated embodiment. Fulcrums 3050 coupled to a common sidewall are spaced from one another in axial direction 3020, and are also aligned with one another in axial direction 3020. In the illustrated embodiment, base 3024 is constructed from aluminum, and each fulcrum 3050 is constructed from a hardened steel pin that is pressed into one of sidewalls 3042, 3044. In other embodiments, base 3024 and fulcrum 3050 may be constructed from any suitable materials that enable counterbalanced seal assembly 3002 to function as described herein.

[0154] Base 3024 also includes a ridge 3052 protruding radially outward from radial inner wall 3046. Ridge 3052 extends axially along the entire length of base 3024, and is sized and shaped to be received in groove 3040. Seal 3022 is configured to slide in axial direction 3020 along ridge 3052. Ridge 3052 facilitates maintaining alignment of seal during installation and removal of seal 3022, and also during operation of a rotary device in which counterbalanced seal assembly 3002 is installed.

[0155] As shown in FIGS. 30 and 31, base 3024 has substantially the same axial length as seal assembly channel 3018, and is coterminous with the sides of rotor arm 3000. Base 3024 also has the same axial length as lips 3030 of seal 3022.

[0156] Each counterweight mechanism 3026 includes a counterweight 3054 and a lever 3056 extending away from counterweight 3054. A notch 3058 is defined in counterweight mechanism 3026 between counterweight 3054 and lever 3056. Notch 3058 is sized and shaped to receive one of fulcrums 3050 therein to provide a pivot point about which counterweight mechanism 3026 pivots.

[0157] As shown in FIG. 32, each counterweight mechanism 3026 is disposed between a corresponding fulcrum 3050 and base 3024 (specifically, radial inner wall 3046 of base 3024). Each counterweight mechanism 3026 is pivotally coupled to one of fulcrums 3050, and is configured to pivot about a pivot axis 3060 that is substantially perpendicular to axial direction 3020. Counterweight mechanism 3026 is suitably constructed from a relatively high density material, including, but not limited to, steel, iron, lead, and combinations thereof.

[0158] Counterweight mechanisms 3026 are configured to control the radial displacement of seal 3022 resulting from rotation of rotor arm 3000, and control the contact pressure exerted by seal 3022 on the inner wall of a rotary device housing resulting from rotation of rotor arm 3000. Specifically, the center of gravity of each counterweight mechanism 3026 is offset towards counterweight 3054. As a result, centrifugal forces acting on counterweight mechanisms 3026 cause counterweight mechanisms 3026 to pivot about pivot axis 3060 defined by a corresponding fulcrum 3050. As rotor arm 3000 rotates, centrifugal forces acting on counterweight mechanisms 3026 cause counterweights 3054 to rotate in a radially outward direction, and cause levers 3056 to rotate in a radially inward direction. Levers 3056 engage lips 3030 of seal 3022, and exert a radially inward force on lips 3030, limiting the radial outward displacement of seal 3022. Counterweight mechanisms 3026 thereby limit the contact pressure between seal 3022 and the inner wall of a rotary device housing.

[0159] In the illustrated embodiment, counterbalanced seal assembly 3002 includes four counterweight mechanisms 3026. Two counterweight mechanisms 3026 are operatively coupled to each sidewall 3042, 3044 of base 3024 via fulcrums 3050. Counterweight mechanisms 3026 coupled to a common sidewall are oriented such that counterweights 3054 of counterweight mechanisms 3026 face each other. That is, each counterweight 3054 extends from notch 3058 towards the other counterweight mechanism 3026 coupled to the common sidewall.

[0160] As noted above, counterbalanced seal assembly 3002 is configured to slide in and out of seal assembly channel 3018 in axial direction 3020. The configuration of counterbalanced seal assembly 3002 facilitates installation, removal, and replacement of counterbalanced seal assembly 3002 and the components thereof. In particular, seal 3022 and counterweight mechanisms 3026 are coupled to a common structure (i.e., base 3024). More specifically, seal 3022 is retained within seal channel 3048 by an engagement between counterweight mechanism 3026 and lips 3030, and counterweight mechanisms 3026 are operatively coupled to base 3024 by fulcrums 3050. As a result, all components of counterbalanced seal assembly 3002 (i.e., base 3024, seal 3022, and counterweight mechanisms 3026) can be moved together as a single unit or module (e.g., by moving base 3024), for example, during installation or removal of counterbalanced seal assembly 3002.

[0161] Additionally, because counterweight mechanisms 3026 are supported within base 3024, counterweight mechanisms 3026 do not need to be aligned with separate cavities, holes, or slots in rotor arm 3000 during installation of counterbalanced seal assembly 3002. Further, because lips 3030 of seal 3022 are configured to slide between counterweight mechanisms 3026 and base 3024, counterweight mechanisms 3026 do not need to be aligned with grooves or channels in seal 3022 during installation or replacement of seal 3022. As a result, seal 3022 can be easily installed or replaced without removing the other components of counterbalanced seal assembly 3002 from rotor arm 3000. In other words, seal 3022 is configured to slide in axial direction 3020 independently of base 3024 and counterweight mechanisms 3026.

[0162] FIG. 33 is a partially exploded view of another embodiment of a counterbalanced seal assembly 3300 suitable for use in a rotary device, such as rotary engine 100 (FIGS. 1 and 2) and compressor 800 (FIG. 20).

[0163] As shown in FIG. 33, counterbalanced seal assembly 3300 includes a crossover or apex seal 3302, a base 3304, a plurality of counterweight mechanisms 3306, and a pair of end seals 3308.

[0164] Seal 3302 is substantially identical to seal 3022 described above with reference to FIGS. 30-32, except seal 3302 has end grooves 3310 defined therein. As such, components of seal 3302 illustrated in FIG. 33 identical to components shown in FIGS. 30-32 are identified with the same reference numbers.

[0165] Each end groove 3310 extends axially inward into body 3028 of seal 3302 from one of first end 3032 and second end 3034, and extends radially through body 3028 from radial outer surface 3038 to radial inner surface 3036. Each end groove 3310 adjoins groove 3040 defined along radial inner surface 3036 of body 3028, forming a single, continuous groove. Each end groove 3310 is sized and shaped to receive a portion of one of end seals 3308.

[0166] Base 3304 is substantially identical to base 3024 described above with reference to FIGS. 30-32, except base 3304 does not include ridge 3052 (FIG. 32), and base 3304 has an end seal channel 3312 defined therein. As such, components of base 3304 illustrated in FIG. 33 identical to components shown in FIGS. 30-32 are identified with the same reference numbers. End seal channel 3312 extends radially inward into radial inner wall 3046 of base 3304, and extends axially for the entire axial length of base 3304. End seal channel 3312 is sized and shaped to receive a portion of each end seal 3308 therein.

[0167] Counterweight mechanisms 3306 are identical to counterweight mechanisms 3026 described with reference to FIGS. 30-32.

[0168] Each end seal 3308 is positioned between seal 3302 and base 3304, and is disposed within groove 3040, one of end grooves 3310, and end seal channel 3312. In the illustrated embodiment, each end seal 3308 has an "L"-shaped cross-section corresponding to the shape of the continuous groove defined by groove 3040 and end grooves 3310. As described in more detail herein, end seals 3308 are configured to form a seal around ends 3032, 3034 of seal 3302, and facilitate maintaining the seal at relatively low temperatures.

[0169] Each end seal 3308 includes a first, sealing end 3314 and a second, non-sealing end 3316 distal from sealing end 3314. Sealing end 3314 of each end seal 3308 is configured to sealingly engage a face plate, such as front plate 230 or rear plate 232 (FIG. 2), of a rotary device in which counterbalanced seal assembly 3300 is installed. End seals 3308 are oriented with non-sealing ends 3316 positioned proximate one another.

[0170] A biasing member, such as a spring (not shown), is disposed between end seals 3308. More specifically, a biasing member is disposed between non-sealing ends 3316 of end seals 3308, and biases end seals 3308 towards a respective face plate, such as front plate 230 or rear plate 232 (FIG. 2), of the rotary device in which counterbalanced seal assembly 3300 is installed.

[0171] FIG. 34 is a partial perspective view of a rotor assembly 3400 in which counterbalanced seal assembly 3300 (FIG. 33) is installed. Rotor assembly 3400 includes a rotor arm 3402, a front ring plate 3404 (broadly, a first ring plate), and a rear ring plate 3406 (broadly, a second ring plate). In use, rotor assembly 3400 is mounted for rotation within a rotary device housing, such as housing 200 (FIG. 2) or housing 2300 (FIG. 23), and enclosed within the housing by face plates, such as front plate 230 and rear plate 232 (FIG. 2). Rotor assembly 3400 functions in substantially the same manner as rotor assembly 300 (FIGS. 2 and 3) described above.

[0172] As noted above, end seals 3308 facilitate maintaining a seal around ends 3032, 3034 of seal 3302 at relatively low temperatures. Specifically, in rotary devices that undergo relatively large temperature fluctuations during operation, such as rotary combustion engines, seal 3302 is "undersized" to permit thermal expansion of seal 3302 in an axial direction. As a result, ends 3032, 3034 of seal 3302 are spaced from the face plates enclosing rotor assembly 3400 at relatively low temperatures, and seal 3302 does not sealingly engage the face plates.

[0173] End seals 3308 maintain a seal around ends 3032, 3034 of seal 3302 by sealingly engaging the face plates enclosing rotor assembly 3400. Specifically, sealing end 3314 of each end seal 3308 is biased against a respective face plate by the biasing member disposed between end seals 3308, thereby forming a seal at each end 3032, 3034 of seal 3302. As the temperature of rotor assembly 3400 increases, seal 3302 expands in an axial direction until ends 3032, 3034 of seal 3302 sealingly engage the face plates enclosing rotor assembly 3400. End seals 3308 likewise undergo thermal expansion, causing non-sealing ends 3316 to expand towards one another, compressing the biasing member disposed between end seals 3308.

[0174] FIG. 35 is an exploded view of another embodiment of a counterbalanced seal assembly 3500 suitable for use in a rotary device, such as rotary engine 100 (FIGS. 1 and 2) and compressor 800 (FIG. 20). FIG. 36 is an end view of counterbalanced seal assembly 3500. As shown in FIGS. 35 and 36, counterbalanced seal assembly 3500 includes a crossover or apex seal 3502, a base 3504, a pair of counterweight mechanisms 3506, a pair of end seals 3508, and a pair of axially extending pins 3510. In the embodiment illustrated in FIGS. 35 and 36, counterweight mechanisms 3506 are hingedly coupled to seal 3502 by pins 3510, as described in more detail below.

[0175] In the illustrated embodiment, seal 3502 has a generally T-shaped cross-section, and includes a head 3512 and a stem 3514 extending generally perpendicular from head 3512. Head 3512 defines a radial outer surface 3516 of seal 3502, and stem 3514 defines a radial inner surface 3518 of seal 3502. In operation, radial outer surface 3516 sealingly engages the inner wall or surface of a rotary device housing, such as housing 200 (FIGS. 1 and 2) or housing 2300 (FIG. 23).

[0176] Seal 3502 extends in an axial or longitudinal direction, indicated by arrow 3520 in FIG. 35, from a first end 3522 of seal 3502 to a second end 3524 of seal 3502. First end 3522 and second end 3524 of seal 3502 each have an end groove 3526 defined therein. Each end groove 3526 extends axially inward into seal 3502 from one of first end 3522 and second end 3524, and extends radially into seal 3502 from radial outer surface 3516. Each end groove 3526 is sized and shaped to receive at least a portion of one of end seals 3508.

[0177] Seal 3502 also has a pin hole 3528 defined therein extending axially through seal 3502 from first end 3522 to second end 3524. Pin hole 3528 is sized and shaped to receive pins 3510 therein. Seal 3502 may include a single, continuous pin hole, or seal 3502 may include two or more separate pin holes. In the illustrated embodiment, pin hole 3528 adjoins end grooves 3526 along first end 3522 and second end 3524 of seal 3502, forming a single, continuous groove. In other embodiments, pin hole 3528 may be separated from end grooves 3526.

[0178] In the illustrated embodiment, seal 3502 has a pair of notches 3530 defined therein. Each notch 3530 extends radially into seal 3502 from radial inner surface 3518, and is sized and shaped to receive a portion of counterweight mechanism 3506. Notches 3530 are spaced apart from one another in longitudinal direction 3520. As shown in FIG. 35, notches 3530 separate pin hole 3528 into three segments, including axial outer segments and an axial inner segment. In some embodiments, seal 3502 may not include notches 3530.

[0179] In the illustrated embodiment, seal 3502 has a unitary construction. That is, seal 3502 is formed from a single piece of material, such as ductile iron. In other embodiments, seal 3502 may have a modular construction. That is, seal 3502 may include multiple sealing members similar to seal 2420 (FIGS. 25-27).

[0180] As shown in FIG. 36, base 3504 includes a pair of opposing sidewalls 3532, 3534, a radial inner wall 3536 extending between and interconnecting sidewalls 3532, 3534 and a pair of ledges 3538 each extending outward from a respective sidewall 3532, 3534. Base 3504 is configured to be slidably received within a seal assembly channel, such as seal assembly channel 3018 (FIG. 31). Ledges 3538 are spaced from one another in a circumferential or transverse direction, and partially define a seal channel 3540 configured to receive seal 3502, in particular, stem 3514 of seal 3502 therein.

[0181] Base 3504 also includes a pair of fulcrums 3542, each configured to pivotally engage one of counterweight mechanisms 3506. Each fulcrum 3542 defines a pivot axis about which counterweight mechanisms 3506 pivot in response to rotation of the rotor in which counterbalanced seal assembly 3500 is installed. In the illustrated embodiment, each pivot axis is substantially parallel to axial direction 3520. In the illustrated embodiment, each fulcrum 3542 includes a support 3544 extending radially inward from a respective ledge 3538 towards radial inner wall 3536 of base 3504.

[0182] Base 3504 also has a pair of counterweight channels 3546 defined therein, each configured to receive a portion of counterweight mechanism 3506 therein. Each counterweight channel 3546 is defined by radial inner wall 3536, a respective sidewall 3532, 3534, a respective ledge 3538, and a respective support 3544. As shown in FIG. 36, supports 3544 extend radially inward towards radial inner wall 3536 a sufficient distance to inhibit counterweight mechanisms 3506 from sliding out of counterweight channels 3546 in a direction transverse to longitudinal direction 3520.

[0183] In the illustrated embodiment, base 3504 is constructed from aluminum, although base 3504 may be constructed from any suitable materials that enable counterbalanced seal assembly 3500 to function as described herein.

[0184] As shown in FIG. 35, each counterweight mechanism 3506 includes a counterweight 3548, a first lever 3550, and a second lever 3552. Counterweight 3548 has a generally oblong shape, and is sized to be received within one of counterweight channels 3546. In other embodiments, counterweight 3548 may be shaped other than generally oblong. First lever 3550 and second lever 3552 each extend away from counterweight 3548, and are spaced from one another in axial direction 3520. First lever 3550 and second lever 3552 are each sized and shaped to be received within one of notches 3530 defined in seal 3502. Each of first lever 3550 and second lever 3552 defines an axially extending groove 3554 configured to cooperate with a respective fulcrum 3542 to cause counterweight mechanism 3506 to pivot in response to rotation of the rotor in which counterbalanced seal assembly 3500 is installed. In other words, each counterweight mechanism 3506 is pivotally coupled to base 3504 via one of fulcrums 3542.

[0185] First lever 3550 and second lever 3552 each include a respective pin hole 3556 defined therein. Pin holes 3556 are each sized and shaped to receive one of pins 3510 therein to hingedly couple counterweight mechanisms 3506 to seal 3502. More specifically, when counterbalanced seal assembly 3500 is assembled, pin holes 3556 are aligned with pin hole 3528 in seal 3502, and each pin 3510 is inserted through pin hole 3528 and pin hole 3556 defined in one of first lever 3550 and second lever 3552. First lever 3550 and second lever 3552 thereby engage seal 3502 via pins 3510.

[0186] First lever 3550 and second lever 3552 are spaced from one another by a distance equal to or greater than the axial distance between notches 3530 such that first lever 3550 is positioned within one of notches 3530 and second lever 3552 is positioned within the other of notches 3530 when counterbalanced seal assembly 3500 is assembled. In the illustrated embodiment, first lever 3550 and second lever 3552 are spaced from one another by a distance greater than the axial distance between notches 3530. More particularly, first lever 3550 and second lever 3552 are spaced from one another such that, when counterbalanced seal assembly 3500 is assembled, the relative axial position of first lever 3550 and second lever 3552 on each counterweight mechanism 3506 alternates. That is, when counterbalanced seal assembly 3500 is assembled, first lever 3550 of one counterweight mechanism 3506 is positioned axially inward of first lever 3550 of the other counterweight mechanism 3506, and second lever 3552 of the one counterweight mechanism 3506 is positioned axially outward of second lever 3552 of the other counterweight mechanism 3506. In other embodiments, the axial spacing between first lever 3550 and second lever 3552 of one counterweight mechanism 3506 may be less than the axial spacing between first lever 3550 and second lever 3552 of the other counterweight mechanism 3506 such that both levers 3550, 3552 of one counterweight mechanism 3506 are positioned axially inward of both levers 3550, 3552 of the other counterweight mechanism 3506. In yet other embodiments, seal 3502 may not include notches 3530, and first lever 3550 and second lever 3552 may be positioned adjacent a respective end 3522, 3524 of seal 3502 when counterbalanced seal assembly 3500 is assembled.

[0187] End seals 3508 operate in substantially the same manner as end seals 3308 described above with reference to FIGS. 33 and 34. In particular, each end seal 3502 is disposed within one of end grooves 3526, and is configured to form a seal around one of ends 3522, 3524 of seal 3502 and facilitate maintaining the seal at relatively low temperatures. A biasing member, such as a coil spring, is positioned within pin hole 3528 between pins 3510 to bias end seals 3508 towards a respective face plate, such as front plate 230 or rear plate 232 (FIG. 2), of the rotary device in which counterbalanced seal assembly 3500 is installed.

[0188] Each pin 3510 is sized and shaped to be received within pin hole 3528 defined in seal 3502 and at least one of pin holes 3556 defined in first lever 3550 and second lever 3552. Each pin 3510 has a sufficient length in axial direction 3520 to hingedly couple one of first lever 3550 and second lever 3552 to seal 3502. In particular, each pin 3510 has a length in axial direction 3520 such that, when counterbalanced seal assembly 3500 is assembled, pin 3510 extends through pin hole 3528 in seal 3502 and pin hole 3556 defined in one of first lever 3550 and second lever 3552. In the illustrated embodiment, each pin 3510 has a length in axial direction such that pin 3510 extends through pin hole 3528 in seal 3502, through pin hole 3556 defined in one of first lever 3550 and second lever 3552, and back into pin hole 3528 defined in seal 3502.

[0189] The illustrated embodiment includes two pins 3510, each configured to be inserted in a respective end 3522, 3524 of seal 3502 to hingedly couple counterweight mechanisms 3506 to seal 3502. In particular, each pin 3510 is formed integrally with one of end seals 3508. Counterbalanced seal assembly 3500 thus has a reduced part count as compared to a counterbalanced seal assembly having pins formed separately from end seals. In other embodiments, pins 3510 may be formed separately from end seals 3508. In one embodiment, for example, end seals 3508 are omitted from counterbalanced seal assembly 3500, and counterbalanced seal assembly 3500 includes discrete pins. In yet other embodiments, counterbalanced seal assembly 3500 may include a single pin configured to extend through pin holes 3556 defined in both first lever 3550 and second lever 3552 when counterbalanced seal assembly 3500 is assembled.

[0190] In use, counterbalanced seal assembly 3500 is installed in a rotor arm of a rotor, such as rotor arm 3000 (FIG. 30). As rotor arm 3000 rotates, centrifugal forces acting on counterweight mechanism 3506 cause counterweight mechanism 3506 to pivot about a pivot point (e.g., fulcrum 3542). The engagement between levers 3550, 3552 and seal 3502 via pins 3510 limits the radial outward displacement of seal 3502 resulting from rotation of rotor arm 3000, thereby limiting the contact pressure between seal 3502 and the inner wall or surface of a rotary device housing, such as housing 200 (FIGS. 1 and 2) or housing 2300 (FIG. 23).

[0191] The hinged connection between seal 3502 and counterweight mechanisms 3506 is not limited to the embodiment illustrated in FIGS. 35 and 36, and may be utilized in other counterbalanced seal assemblies described herein. In one embodiment, for example, seal 3502 and counterweight mechanism 3506 of counterbalanced seal assembly 3500 may be utilized in rotor arm 2408 of rotor 2400 (FIGS. 24 and 25), with fulcrum 2448 defining the pivot point about which counterweight mechanisms 3506 pivot.

[0192] As compared to some known rotary engine systems, the rotary engines disclosed herein facilitate improving the reliability and service life of crossover seals within the rotary engine. In particular, the rotary engines disclosed herein include counterbalanced seal assemblies that include a seal and a counterweight mechanism configured to control radial displacement of the seal. By controlling radial displacement of the seal, the counterweight mechanism controls the contact pressure between the seal and an inner wall of a housing that houses the rotary engine, and counteracts centrifugal forces imparted on the seal from rotation of the rotor within the rotary engine.

[0193] Additionally, in some embodiments, the counterbalanced seal assemblies disclosed herein include a control mechanism configured to apply a variable radial force to the seal to control the contact pressure between the seal and the inner wall of the rotary engine housing. The control mechanism can be utilized to selectively vary the radial force applied to the seal at specified times and/or rotational positions during a single stroke or revolution of the rotor, thereby enabling various engine functions, such as turbocharging, supercharging, and chamber coupling and de-coupling. Further, by enabling selective control of the radial force applied to the seal, the control mechanism enables "on the fly" adjustments to rotary engine operation. For example, the control mechanism can be utilized to lower the compression ratio of a rotary engine in a vehicle while operating at freeway cruising speeds to increase fuel efficiency. The control mechanism may also be utilized to increase the compression ratio of a rotary engine when additional power is needed. The control mechanism also permits a rotary engine to run on different types of fuel by enabling selective adjustment of compression ratios within the rotary engine.

[0194] Additionally, in some embodiments, the configuration of the counterbalanced seal assemblies disclosed herein facilitates installation, removal, and replacement of the counterbalanced seal assemblies. In particular, the seal and counterweight mechanisms of some counterbalanced seal assemblies disclosed herein are coupled to a common structure, such as a base, that enables all components of the counterbalanced seal assembly to be moved together as a single unit or module.

[0195] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

[0196] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A rotary device comprising: a housing having an inner surface; and a rotor assembly mounted for rotation in said housing about an axis defining an axial direction of said rotary device, said rotor assembly comprising: a rotor comprising a central portion and a plurality of arms extending radially outward from said central portion, each arm having a distal end disposed for sliding engagement with said inner surface, at least one of said arms having a channel defined therein; and a seal assembly disposed within the channel, said seal assembly comprising: a seal; a base defining a seal channel configured to receive said seal; and a counterweight mechanism pivotally coupled to said base, said counterweight mechanism configured to control a contact pressure exerted by said seal on said inner surface resulting from rotation of said rotor.

2. A rotary device in accordance with claim 1, wherein said seal assembly is configured to slide in the axial direction within the channel defined in said at least one arm.

3. A rotary device in accordance with claim 1, wherein said seal is configured to slide independently of said base in the axial direction.

4. A rotary device in accordance with claim 1, wherein said seal comprises a lip, said lip slidably received between said counterweight mechanism and said base, said counterweight mechanism engaging said lip to control the contact pressure exerted by said seal on said inner surface.

5. A rotary device in accordance with claim 1, wherein said base comprises a fulcrum defining a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially perpendicular to the axial direction.

6. A rotary device in accordance with claim 1, further comprising a pin hingedly coupling said counterweight mechanism to said seal.

7. A rotary device in accordance with claim 1, wherein said base comprises a fulcrum defining a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially parallel to the axial direction.

8. A rotary device in accordance with claim 1, wherein said seal includes a first end and a second end distal from said first end, each of said first end and said second end having an end groove defined therein, said seal assembly further comprising a pair of end seals, each end seal disposed within one of the end grooves.

9. A rotary device in accordance with claim 1, wherein said rotor assembly further comprises at least one rocker pivotally coupled to said rotor for pivoting between a first position spaced from said inner surface of said housing and a second position adjacent said inner surface of said housing, wherein pivoting of said rocker causes said rotor to rotate.

10. A seal assembly for use in a rotary device including a rotor, said seal assembly comprising: a seal; a base defining a seal channel extending in a longitudinal direction, said seal disposed within the seal channel; and a counterweight mechanism pivotally coupled to said base, said counterweight mechanism configured to control radial displacement of said seal resulting from centrifugal forces imparted on said seal by rotation of the rotor.

11. A seal assembly in accordance with claim 10, wherein said seal is configured to slide independently of said base in the longitudinal direction.

12. A seal assembly in accordance with claim 10, wherein said seal comprises a lip slidably received between said counterweight mechanism and said base, said counterweight mechanism engaging said lip to control radial displacement of said seal.

13. A seal assembly in accordance with claim 10, wherein said base comprises a fulcrum defining a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially perpendicular to the longitudinal direction.

14. A seal assembly in accordance with claim 10, further comprising a pin hingedly coupling said counterweight mechanism to said seal.

15. A seal assembly in accordance with claim 10, wherein said base comprises a fulcrum defining a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially parallel to the longitudinal direction.

16. A seal assembly in accordance with claim 10, wherein said seal assembly is configured to be slidably received within a seal assembly channel defined within one of the arms of the rotor.

17. A seal assembly in accordance with claim 10, wherein said seal includes a first end and a second end distal from said first end, each of said first end and said second end having an end groove defined therein, said seal assembly further comprising a pair of end seals, each end seal disposed within one of the end grooves.

18. A rotary device comprising: a housing having an inner surface; and a rotor assembly mounted for rotation in said housing about an axis defining an axial direction of said rotary device, said rotor assembly comprising: a rotor comprising a central portion and a plurality of arms extending radially outward from said central portion, each arm having a distal end disposed for sliding engagement with said inner surface, at least one of said arms having a channel defined therein; and a seal assembly disposed within the channel, said seal assembly comprising: a seal; a base defining a seal channel, said seal disposed within the seal channel, said base comprising a fulcrum; and a counterweight mechanism operatively coupled to said fulcrum, said counterweight mechanism comprising a counterweight and a lever extending away from said counterweight, wherein rotation of said rotor causes said counterweight mechanism to pivot about said fulcrum and causes said lever to exert a radial inward force on said seal.

19. A rotary device in accordance with claim 18, wherein said fulcrum defines a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially perpendicular to the axial direction.

20. A rotary device in accordance with claim 18, wherein said seal comprises a body and a lip extending outward from said body, wherein rotation of said rotor causes said lever to exert a radial inward force on said lip.

21. A rotary device in accordance with claim 18, further comprising a pin hingedly coupling said counterweight mechanism to said seal.

22. A rotary device in accordance with claim 18, wherein said fulcrum defines a pivot axis about which said counterweight mechanism pivots, the pivot axis substantially parallel to the axial direction.

23. A rotary device in accordance with claim 18, wherein said rotor assembly further comprises at least one rocker pivotally coupled to said rotor for pivoting between a first position spaced from said inner surface of said housing and a second position adjacent said inner surface of said housing, wherein pivoting of said rocker causes said rotor to rotate.

24. A seal assembly for use in a rotary device including a rotor, said seal assembly comprising: a seal; a base defining a seal channel, said seal disposed within the seal channel, said base comprising a fulcrum; and a counterweight mechanism operatively coupled to said fulcrum, said counterweight mechanism comprising a counterweight and a lever extending away from said counterweight, wherein rotation of said rotor causes said counterweight mechanism to pivot about said fulcrum and causes said lever to exert a radial inward force on said seal.