Rotary engine with axially symmetrical ring gear

Abstract

An improved rotary engine has a pair of symmetrically disposed ring gears.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 400,797, filed on August 25, 2022, the entire contents of which are incorporated herein by reference.

[0002] This invention was made with Government support under Agreement No. HR0011-16-9-0009 awarded by DARPA. The Government has certain rights in this invention. Technical Field

[0003] The present invention relates to a rotary engine having an axially symmetrical ring gear for distributing load during operation. Background Art

[0004] Wankel type rotary engines employ a single ring gear and pinion to control the angular position of the rotor relative to the housing during operation. However, high compression engines such as diesel engines produce much higher dynamic and gas loads than previous generations of rotary gasoline engines, and a single ring gear and pinion may not be adequate for their operation. Summary of the invention

[0005] According to one embodiment of the present invention, an improved pistonless rotary engine type includes: (i) a rotor having a central rotation axis and a first axial face and a second axial face, (ii) a housing having a plurality of working chambers; (iii) a pair of side covers axially covering a first side and a second side of the rotor and coupled to the housing; (iv) an output shaft coupled to the rotor, wherein the improvement includes a pinion gear and a pair of ring gears, the pinion gear being arranged around the output shaft to support rotation relative to the output shaft and extending through the central axis of the rotor and rigidly coupled to the rotor, the pinion gear The invention comprises: a first section and a second section, wherein the first section and the second section extend axially beyond the first axial face and the second axial face of the rotor respectively; and a plurality of teeth, wherein the plurality of teeth are circumferentially arranged around the outer radial surface of the pinion gear, the pair of ring gears are symmetrically arranged on opposite sides of the rotor, each ring gear is attached to the inner side face of one of the side covers, each of the ring gears has a plurality of teeth, wherein the plurality of teeth are circumferentially arranged around the inner radial surface of each of the ring gears and are configured to engage with the teeth of a corresponding one of the pinion gear sections.

[0006] In some embodiments, the teeth of the first and second segments of the pinion gear are crowned. In some embodiments, the teeth of each of the ring gears are crowned.

[0007] In some embodiments, each of the ring gears includes a flexible thin continuous rim around its outer circumference.

[0008] In some embodiments, the pinion gear is coupled to the output shaft via a first bearing. The first bearing may be a fluid dynamic bearing.

[0009] In some embodiments, each ring gear is attached to the inner side of one of the side covers by a spring pin. In some embodiments, the output shaft extends through each of the pair of side covers.

[0010] In some embodiments, each of the pair of side covers is coupled to the output shaft via a second bearing. In some embodiments, the second bearing is a fluid dynamic bearing.

[0011] In some embodiments, the inner axial face of each of the ring gears includes a groove and a series of pad cutouts, the series of pad cutouts being circumferentially disposed around at least a portion of the circumference of the inner axial face of each of the ring gears. In some embodiments, the groove and the series of pad cutouts are circumferentially disposed around the entire circumference of the inner axial face of each of the ring gears. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] This patent or application file contains at least one drawing executed in color. Copies of color drawings of this patent or patent application publication will be provided by the Office upon request and payment of the necessary fee.

[0013] The foregoing features of the embodiments will be more readily understood by reading the following detailed description with reference to the accompanying drawings, in which:

[0014] Figure 1 is a photograph of a rotary engine mounted on a bracket according to an embodiment of the present invention.

[0015] Figure 2 is an exploded view of a rotary engine component according to an embodiment of the present invention.

[0016] Figure 3 According to an embodiment of the present invention Figure 2 A perspective view of an assembly of rotating engine components.

[0017] Figure 4 According to an embodiment of the present invention, there is no side cover Figure 1 Photo of a rotary engine.

[0018] Figure 5is a perspective view of selected components of a rotary engine in its normal configuration having a pair of ring gears symmetrically disposed on opposite sides of a rotor (not shown) in accordance with an embodiment of the present invention.

[0019] Figure 6 A misalignment between the pinion and the two ring gears is shown according to an embodiment of the invention, which is evidenced by the loss of symmetry of the two ring gears.

[0020] Fig. 7A A vertical misalignment between a pinion gear and a ring gear is shown according to an embodiment of the present invention. Figure 7B Horizontal misalignment between the pinion gear and the ring gear is shown according to an embodiment of the present invention. Figure 7C A rotational misalignment between a pinion gear and a ring gear is shown in accordance with an embodiment of the present invention.

[0021] Figure 8 is a pinion gear with a crown according to an embodiment of the present invention.

[0022] Fig. 9 is a ring gear with a crown according to an embodiment of the present invention.

[0023] Fig. 10A is a ring gear according to an embodiment of the present invention, the ring gear having a flexible thin continuous rim around its outer circumference. Fig. 10B According to an embodiment of the present invention Fig. 10B A perspective view of a portion of a ring gear.

[0024] Fig.11 is a perspective view from one side of a rotor (side cover and housing removed) of a rotary engine according to an embodiment of the present invention, the rotor being rigidly fixed to a pinion gear coupled to an output shaft via a bearing (e.g., a hydrodynamic bearing). The pinion gear extends through the central axis of the rotor and has a first section and a second section extending axially beyond the axial face of the rotor, each section engaging a corresponding ring gear.

[0025] Fig. 12A According to an embodiment of the present invention Figure 1 A cross section of a rotary engine showing the oil path through the output shaft. Fig. 12B An engine cross section and bearing arrangement according to an embodiment of the invention is shown. DETAILED DESCRIPTION

[0026] Definitions. Unless the context requires otherwise, the following terms used in this specification and the appended claims shall have the meanings indicated:

[0027] "Rotary engine" and "pistonless rotary engine" are used interchangeably herein and refer to a rotary engine that does not include a piston.

[0028] By "compliant" coupling of components of a rotary engine according to embodiments of the present invention is meant providing a relatively flexible coupling between the components.

[0029] Figure 1 is a photograph of a rotary engine mounted on a bracket according to an embodiment of the present invention. In some embodiments, the rotary engines described herein include, but are not limited to, engines and aspects of engines disclosed in U.S. Patent Nos. 8,863,724; 8,365,699; 8,863,723; 9,353,623; 9,382,851; 9,528,435; 9,644,570; 9,810,068; 10,196,970; 10,125,675; 10,221,690; and 11,149,547, the disclosures of each of which are incorporated herein by reference in their entirety.

[0030] Figure 2 2 is an exploded view of a rotary engine component according to an embodiment of the present invention, comprising: a first side cover including an end plate 200 and a front plate 202 ; a housing 204 ; and a second side cover including an end plate 208 and a back plate 206 .

[0031] Figure 3 According to an embodiment of the present invention Figure 2 A perspective view of an assembly of rotating engine components.

[0032] Figure 4 According to an embodiment of the present invention Figure 1 4. A photograph of a rotary engine (without side covers) showing a rotor 402 within a housing 204 with an attached pinion 404, an output shaft 406, and a rotor thrust surface 408. The pinion 404 includes a plurality of teeth disposed circumferentially about an outer radial surface of the pinion, and the pinion is rigidly fixed to the rotor 402. Here, the rotor forms three separate working chambers defined by the housing 204, the front plate 202, the back plate 206 (not shown), the seals (not shown), and the rotor 402 itself. During operation, the rotor nutates, i.e., the rotor moves with its center along a circle defined by the eccentricity of the shaft, and simultaneously rotates about its center, thereby causing compression and allowing the gas to expand within the working chambers.

[0033] In order to avoid contact between the rotor 402 and the housing 204 during operation, rotary engines require gearing to ensure that the rotor rotates at 1 / 2 the shaft speed in the opposite direction of the shaft eccentricity. For example, in a Wankel type rotary engine, a single ring gear and pinion gear are sufficient to control the angular position of the rotor relative to the housing. However, compression ignition (CI) diesel engines have much higher loads than previous generations of rotary gasoline engines and benefit from more comprehensive gearing in various embodiments.

[0034] Figure 5 is a perspective view of selected components of a rotary engine embodiment in its normal configuration according to an embodiment of the present invention having a pair of ring gears 500 symmetrically disposed on opposite sides of a rotor (not shown) to control the angular position of the rotor. The ring gear 500 includes a plurality of teeth disposed circumferentially around the inner radial surface of the ring gear that allow the ring gear 500 to engage the pinion 404. According to an embodiment of the present invention, the pinion 404 is coupled to the output shaft 406. In some embodiments, the pinion 404 is coupled to the output shaft 406 via a bearing (e.g., a fluid dynamic bearing).

[0035] In some embodiments, a hydrodynamic thrust bearing between the rotor 402 and the ring gear 500 is formed by an oil film between the rotor thrust surface 408 and the inner axial face of the ring gear 500. The grooves 504 and pad cutouts 502 on the inner axial face of the ring gear 500 promote greater compliance by providing increased oil lubrication and flow between the rotor thrust surface 408 and the inner axial face of the ring gear 500. The grooves 504 and series of pad cutouts are disposed circumferentially around at least a portion of the circumference of the inner axial face of the ring gear 500. In some embodiments, the grooves 504 and series of pad cutouts are disposed circumferentially around the entire circumference of the inner axial face of the ring gear 500. In some embodiments, the deeper grooves on the inner axial face of the ring gear 500 can be used to mount a compliant oil ring seal that also extends on the rotor thrust surface 408.

[0036] The dual ring gear design allows for a significant reduction in the loads and stresses that a single ring gear would experience, since these loads and stresses are shared between the two ring gears. Although the load capacity is greatly increased, the dual ring gear design may introduce misalignment between the pinion 404 and the two ring gears 500, such as Figure 6 As shown (rotor not shown), this is evidenced by the loss of symmetry of the two ring gears. This misalignment may cause one of the ring gears to be subjected to a greater load than the other of the ring gears. Figure 6Also shown is a pinion segment 602 , which is rigidly attached to the rotor 402 (not shown), in accordance with an embodiment of the present invention.

[0037] Fig. 7A The vertical misalignment between the pinion gear 404 and the ring gear 500 is shown. Figure 7B A horizontal misalignment between the pinion gear 404 and the ring gear 500 is shown. Figure 7C A rotational misalignment between pinion gear 404 and ring gear 500 is shown.

[0038] like Figure 8 The crown 802 of the pinion 404 shown and / or Fig. 9 The crown 902 of the ring gear 500 shown reduces or eliminates misalignment between the pinion 404 and the ring gear 500. The crown reduces edge loading of misaligned gears, while the compliance between the pinion 404 and the ring gear 500 (with or without the crown) allows small movements of the pinion 404 relative to the dual ring gear system, thereby distributing the load more evenly between the two ring gears. In some embodiments, compliance is achieved by utilizing an oil film to fill the gaps in the hydrodynamic bearing.

[0039] In some embodiments, compliance can be achieved by using a ring gear 500 having a flexible thin continuous rim 1000, such as Fig. 10A and Fig. 10B As shown, the gear is mounted to the side cover by the flexible thin continuous rim 1000. The ring gear with the thin continuous rim can be mounted to the side cover using a compliant washer (e.g., a Belleville washer). The flexible thin continuous rim 1000 allows the ring gear 500 to become compliant under dynamic and gas loads and thus mitigate misalignment. In some embodiments, compliance can be achieved by utilizing a separate pinion with a compliant element (e.g., a spring), a compliant bearing structure, or a compliant rotor.

[0040] Fig.11 4 is a perspective view of a rotary engine (side covers and housing removed) according to an embodiment of the present invention from one side of a rotor 402 rigidly fixed to a pinion 404 coupled to an output shaft 406 via a bearing (e.g., a hydrodynamic bearing). Pinion 404 extends through the central axis of rotor 402 and has a first section and a second section extending axially beyond the axial face of the rotor, each section engaging a corresponding ring gear 500.

[0041] Fig. 12A and Fig. 12B According to an embodiment of the present invention Figure 1A cross section of a rotary engine showing the oil flow path and the oil film position, respectively. During operation of the rotary engine, the high temperature of the combustion gases causes the temperature of the rotor 402 and the housing 204 to increase. In order to prevent coking of the lubricating oil film, the rotor and the housing must be cooled. In addition, in order to support the gas and inertial loads, the rotor is supported by bearings in the eccentric shaft, and the eccentric shaft is supported by bearings in the end plates. In a preferred embodiment, these bearings are hydrodynamic, operating with oil as the working fluid. As Fig. 12A and Fig. 12B As shown, oil is supplied internally through passages in the eccentric output shaft to the hydrodynamic bearings, pinion 404, ring gear 500, seals and the rotor itself. Fig. 12B An example of an engine cross section and bearing arrangement is shown, Fig. 12A An embodiment of an oil passage through the output shaft is shown.

[0042] Various embodiments of the present invention may be characterized by the potential claims listed in the paragraphs following this paragraph (and before the actual claims provided at the end of this application). These potential claims form part of the written description of this application. Therefore, the subject matter of the following potential claims may be presented as actual claims in a subsequent proceeding related to this application or any application claiming priority based on this application. The inclusion of such potential claims should not be interpreted as meaning that the actual claims do not cover the subject matter of the potential claims. Therefore, a decision not to present these potential claims in a subsequent proceeding should not be interpreted as donating the subject matter to the public.

[0043] Without limitation, potential subject matter that may be claimed (prefixed with the letter "P" to avoid confusion with the actual claims set forth below) includes: P1. An improved pistonless rotary engine, the type of pistonless rotary engine comprising: (i) a rotor having a central rotation axis and a first axial face and a second axial face; (ii) a housing having a plurality of working chambers; (iii) a pair of side covers axially disposed on a first side and a second side of the rotor and coupled to the housing; and (iv) an output shaft coupled to the rotor, wherein the improvement comprises: a pinion gear disposed about the output shaft to support rotation relative to the output shaft and extending through the central axis of the rotor and rigidly coupled to the rotor, the pinion gear having: a first section and a second section, the first section and the second section extending axially beyond the first axial face and the second axial face of the rotor, respectively; and a plurality of teeth disposed circumferentially about an outer radial surface of the pinion gear; and A pair of ring gears, the pair of ring gears are symmetrically arranged on opposite sides of the rotor, each ring gear is attached to the inner side surface of one of the side covers, each of the ring gears has a plurality of teeth, the plurality of teeth are circumferentially arranged around the inner radial surface of each of the ring gears, and the plurality of teeth are configured to engage with the teeth of a corresponding one of the pinion gear sections.

[0044] P2. An improved pistonless rotary engine according to claim P1, wherein the teeth of the first section and the second section of the pinion are crowned.

[0045] P3. An improved pistonless rotary engine according to any one of claims Pl-P2, wherein the teeth of each of the ring gears are crowned.

[0046] P4. An improved pistonless rotary engine according to any one of claims Pl-P3, wherein each of the ring gears comprises a flexible thin continuous rim around its outer circumference.

[0047] P5. An improved pistonless rotary engine according to any one of claims Pl-P4, wherein the pinion is connected to the output shaft via a first bearing.

[0048] P6. An improved pistonless rotary engine according to claim P5, wherein the first bearing is a fluid dynamic bearing.

[0049] P7. An improved pistonless rotary engine according to any one of claims Pl-P6, wherein each ring gear is attached to the inner side of one of the side covers by a spring pin.

[0050] P8. An improved pistonless rotary engine according to any one of claims Pl-P7, wherein the output shaft extends through each of the pair of side covers.

[0051] P9. An improved pistonless rotary engine according to claim P8, wherein each of the pair of side covers is connected to the output shaft via a second bearing.

[0052] P10. An improved pistonless rotary engine according to claim P9, wherein the second bearing is a fluid dynamic bearing.

[0053] P11. An improved pistonless rotary engine according to any one of claims 1-P10, wherein the inner axial face of each of the ring gears comprises a groove and a series of pad cuts, the series of pad cuts being circumferentially arranged around at least a portion of the circumference of the inner axial face of each of the ring gears.

[0054] P12. An improved pistonless rotary engine according to claim P11, wherein the groove and the series of pad cutouts are arranged circumferentially around the entire circumference of the inner axial face of each of the ring gears.

[0055] The embodiments of the present invention described above are merely exemplary; many variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to fall within the scope of the present invention as defined by any of the appended claims.

Claims

1. An improved pistonless rotary engine, the pistonless rotary engine of this type comprising: (i) a rotor having a central rotational axis and a first axial face and a second axial face; (ii) a housing having a plurality of working chambers; (iii) a pair of side covers disposed on a first side and a second side of the rotor in an axial direction and coupled to the housing; and (iv) an output shaft coupled to the rotor, wherein the improvement comprises: a pinion gear disposed about the output shaft to support rotation relative to the output shaft, the pinion gear extending through the central axis of the rotor and rigidly coupled to the rotor, the pinion gear having: a first section and a second section, the first section and the second section extending axially beyond the first axial face and the second axial face of the rotor, respectively; and a plurality of teeth disposed circumferentially about an outer radial surface of the pinion gear; and A pair of ring gears are symmetrically arranged on opposite sides of the rotor, each ring gear is attached to the inner side surface of one of the side covers, and each of the ring gears has a plurality of teeth, which are circumferentially arranged around the inner radial surface of each of the ring gears and are configured to engage with the teeth of a corresponding one of the pinion gear sections.

2. The improved pistonless rotary engine according to claim 1, wherein: The teeth of the first and second sections of the pinion are crowned.

3. An improved pistonless rotary engine according to any one of the preceding claims, wherein: The teeth of each of the ring gears are crowned.

4. An improved pistonless rotary engine according to any one of the preceding claims, wherein: Each of the ring gears includes a flexible thin continuous rim around its outer circumference.

5. An improved pistonless rotary engine according to any one of the preceding claims, wherein: The pinion gear is coupled to the output shaft via a first bearing.

6. The improved pistonless rotary engine according to claim 5, wherein: The first bearing is a hydrodynamic bearing.

7. An improved pistonless rotary engine according to any one of the preceding claims, wherein: Each ring gear is attached to the inside face of one of the side covers by a spring pin.

8. An improved pistonless rotary engine according to any one of the preceding claims, wherein: The output shaft extends through each of the pair of side covers.

9. The improved pistonless rotary engine according to claim 8, wherein: Each of the pair of side covers is coupled to the output shaft through a second bearing.

10. The improved pistonless rotary engine of claim 9, wherein: The second bearing is a hydrodynamic bearing.

11. An improved pistonless rotary engine according to any one of the preceding claims, wherein: The inner axial face of each of the ring gears includes a groove and a series of pad cutouts disposed circumferentially around at least a portion of a circumference of the inner axial face of each of the ring gears.

12. The improved pistonless rotary engine of claim 11, wherein: The groove and the series of pad cutouts are disposed circumferentially around the entire circumference of the inner axial face of each of the ring gears.

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