Engine crankshaft assembly with gear interface

Abstract

The invention relates to an engine crankshaft assembly with a gear interface. A crankshaft assembly includes a crankshaft body extending along an axis of rotation. The crankshaft body includes: bearing journals mutually coaxial with the axis of rotation and spaced apart from each other along the length of the crankshaft body; and crank pins spaced apart from each other along the length of the crankshaft body and axially offset from the rotation axis. The crankshaft body further includes a crank web protruding radially from the axis of rotation and interconnecting the bearing journal and the crank pin; and a flange extending from the distal end of the crankshaft body having a conical gear engagement surface.

Description

Technical Field

[0001] introduction

[0002] The present disclosure relates generally to torque-transmitting shafts. More specifically, aspects of the present disclosure relate to crankshaft assemblies for internal combustion engines. Background Art

[0003] In automotive applications, for example, the vehicle powertrain is typically represented by a prime mover that delivers drive torque to the vehicle's final drive system (e.g., differential, axles, road wheels, etc.) through an automatically or manually shifted power transmission. Prime movers for automobiles may include reciprocating piston internal combustion engines (ICEs), in which the engine's crankshaft converts the reciprocating linear movement of the engine's pistons into rotational movement, which is output as drive torque to propel the vehicle. Summary of the Invention

[0004] A crankshaft assembly is disclosed herein. The crankshaft assembly includes a crankshaft body extending along a rotational axis. The crankshaft body includes bearing journals coaxial with the rotational axis and spaced apart from one another along the length of the crankshaft body, and a crankpin spaced apart from one another along the length of the crankshaft body and axially offset from the rotational axis. The crankshaft body also includes a crank web projecting radially from the rotational axis and interconnecting the bearing journals and the crankpin, and a flange extending from a distal end of the crankshaft body and having a conical gear-engaging surface.

[0005] Another aspect of the present disclosure may be wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0006] Another aspect of the present disclosure may be wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0007] Another aspect of the present disclosure may be wherein the flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0008] Another aspect of the present disclosure may include a gear having a conical flange engagement surface that is complementary to a conical gear engagement surface.

[0009] Another aspect of the present disclosure may be wherein the gear includes helical teeth extending from a radially outer surface of the gear.

[0010] Another aspect of the present disclosure may be wherein the helical teeth on the gear are right-hand helical teeth.

[0011] Another aspect of the present disclosure may be wherein each of the plurality of bearing journals defines a journal cavity therein.

[0012] Another aspect of the present disclosure may be wherein each of the plurality of crankpins defines a crankpin cavity therein.

[0013] Another aspect of the present disclosure may be wherein each of the plurality of crank webs defines a web cavity therein.

[0014] A method for manufacturing a crankshaft assembly is disclosed herein. The method includes forming a crankshaft body along a rotational axis. The crankshaft body includes bearing journals coaxial with the rotational axis and spaced apart from one another along the length of the crankshaft body; and crankpins spaced apart from one another along the length of the crankshaft body and axially offset from the rotational axis. The crankshaft body also includes a crank web projecting radially from the rotational axis and interconnecting the bearing journals and the crankpin; and a flange extending from a distal end of the crankshaft body and having a conical gear-engaging surface.

[0015] Another aspect of the present disclosure may be wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0016] Another aspect of the present disclosure may be wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0017] Another aspect of the present disclosure may be wherein the flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0018] Another aspect of the present disclosure may include a gear having a conical flange engagement surface that is complementary to a conical gear engagement surface.

[0019] A motor vehicle is disclosed herein. The motor vehicle includes: a vehicle body; road wheels rotatably attached to the vehicle body; and an internal combustion engine (ICE) assembly attached to the vehicle body. The ICE assembly is operable to output engine torque to one or more of the road wheels to thereby propel the motor vehicle. The ICE assembly includes: an engine block defining cylinder bores; pistons, each piston being reciprocally movable within a corresponding one of the cylinder bores; and a crankshaft assembly. The crankshaft assembly includes a crankshaft body extending along a rotational axis. The crankshaft body includes: bearing journals that are coaxial with the rotational axis and spaced apart from each other along the length of the crankshaft body; and crankpins that are spaced apart from each other along the length of the crankshaft body and axially offset from the rotational axis. The crankshaft body also includes: a crank web that projects radially from the rotational axis and interconnects the bearing journals and the crankpin; and a flange that extends from a distal end of the crankshaft body and has a conical gear engaging surface.

[0020] Another aspect of the present disclosure may be wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0021] Another aspect of the present disclosure may be wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0022] Another aspect of the present disclosure may be wherein the flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0023] Another aspect of the present disclosure may include a gear having a conical flange engagement surface that is complementary to a conical gear engagement surface.

[0024] The invention includes the following technical solutions:

[0025] 1. A crankshaft assembly comprising:

[0026] A crankshaft body extending along a rotation axis, the crankshaft body comprising:

[0027] a plurality of bearing journals coaxial with the axis of rotation and spaced apart from one another along the length of the crankshaft body;

[0028] a plurality of crank pins spaced apart from one another along the length of the crankshaft body and axially offset from the axis of rotation;

[0029] a plurality of crank webs projecting radially from the rotational axis and interconnecting the bearing journals and the crank pin; and

[0030] A flange extending from a distal end of the crankshaft body has a conical gear engaging surface.

[0031] 2. The crankshaft assembly of claim 1 , wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0032] 3. The crankshaft assembly of claim 2, wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0033] 4. The crankshaft assembly of claim 2, wherein the flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0034] 5. The crankshaft assembly of claim 2, comprising a gear having a conical flange engaging surface complementary to the conical gear engaging surface.

[0035] 6. The crankshaft assembly of claim 5, wherein the gear includes helical teeth extending from a radially outer surface of the gear.

[0036] 7. The crankshaft assembly of claim 6, wherein the helical teeth on the gear are right-hand helical teeth.

[0037] 8. The crankshaft assembly of claim 1 , wherein each of the plurality of bearing journals defines a journal cavity therein.

[0038] 9. The crankshaft assembly of claim 8, wherein each of the plurality of crankpins defines a crankpin cavity therein.

[0039] 10. The crankshaft assembly of claim 9, wherein each of the plurality of crank webs defines a web cavity therein.

[0040] 11. A method of manufacturing a crankshaft assembly, the method comprising:

[0041] A crankshaft body is formed along a rotation axis, the crankshaft body comprising:

[0042] a plurality of bearing journals coaxial with the axis of rotation and spaced apart from one another along the length of the crankshaft body;

[0043] a plurality of crank pins spaced apart from one another along the length of the crankshaft body and axially offset from the axis of rotation;

[0044] a plurality of crank webs projecting radially from the rotational axis and interconnecting the bearing journals and the crank pin; and

[0045] A flange extending from a distal end of the crankshaft body has a conical gear engaging surface.

[0046] 12. The method of claim 11, wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0047] 13. The method of claim 12, wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0048] 14. The method of claim 12, wherein the flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0049] 15. The method of claim 12, comprising a gear having a conical flange engagement surface complementary to the conical gear engagement surface.

[0050] 16. A motor vehicle comprising:

[0051] body;

[0052] a plurality of road wheels rotatably attached to the vehicle body; and

[0053] an internal combustion engine (ICE) assembly attached to the vehicle body and operable to output engine torque to one or more of the road wheels to thereby propel the motor vehicle, the ICE assembly having: an engine block defining a plurality of cylinder bores; a plurality of pistons, each piston reciprocally movable within a respective one of the cylinder bores; and a crankshaft assembly comprising:

[0054] a crankshaft body extending along the axis of rotation;

[0055] a plurality of bearing journals coaxial with the axis of rotation and spaced apart from one another along the length of the crankshaft body;

[0056] a plurality of crank pins spaced apart from one another along the length of the crankshaft body and axially offset from the axis of rotation;

[0057] a plurality of crank webs projecting radially from the rotational axis and interconnecting the bearing journals and the crank pin; and

[0058] A flange extending from a distal end of the crankshaft body has a conical gear engaging surface.

[0059] 17. The motor vehicle of claim 16, wherein the conical gear engaging surface tapers toward a distal end of the crankshaft body.

[0060] 18. A motor vehicle according to claim 17, wherein the conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

[0061] 19. The motor vehicle of claim 17, wherein the flange includes a first axially facing surface and a second axially facing surface, and wherein the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

[0062] 20. The motor vehicle of claim 17 including a gear having a conical flange engaging surface complementary to the conical gear engaging surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a front perspective view illustration of a representative motor vehicle having an inset schematic illustration of a representative reciprocating piston internal combustion engine assembly with an engine crankshaft having an internal reinforcement structure in accordance with aspects of the present disclosure.

[0064] Figure 2is a side view illustration of a representative engine crankshaft assembly with an I-beam core reinforcement according to aspects of the present disclosure.

[0065] Figure 3 The edge of the crankshaft Figure 2 A cross-sectional view taken along line 3-3.

[0066] Figure 4 yes Figure 3 An enlarged cross-sectional view of a crankshaft illustrating the outer surface of the crankshaft flange.

[0067] Representative embodiments of the present disclosure are shown in the accompanying drawings by way of non-limiting example and are described in more detail below. However, it should be understood that the novel aspects of the present disclosure are not limited to the specific forms illustrated in the accompanying drawings listed above. Instead, the present disclosure is intended to cover all modifications, equivalents, combinations, sub-combinations, permutations, groups, and alternatives that fall within the scope of the present disclosure, such as those encompassed by the appended claims. DETAILED DESCRIPTION

[0068] The present disclosure allows for embodiments in many different forms. Representative examples of the present disclosure are shown in the accompanying drawings and are described in detail herein with the understanding that these embodiments are provided as illustrations of the disclosed principles, rather than limitations on the broad aspects of the present disclosure. To this end, elements and limitations that are described in the abstract, introduction, summary, illustrations, and detailed description sections but not explicitly set forth in the claims should not be incorporated into the claims, either individually or collectively, by implication, inference, or otherwise. In addition, the drawings discussed herein may not be drawn to scale and are provided for guidance purposes only. Therefore, the specific and relative dimensions shown in the drawings are not to be interpreted as limiting.

[0069] For the purposes of this detailed description, unless otherwise stated: the singular includes the plural and vice versa; the words "and" and "or" shall be both conjunctions and disjunctions; the words "any" and "all" shall both mean "any and all"; and the words "including," "containing," "comprising," "having," and their permutations shall each mean "including but not limited to." In addition, approximate words (such as, "about," "almost," "substantially," "approximately," and the like) may each be used herein in the sense of, for example, "at, close to, or nearly at," or "within 0-5% of," or "within acceptable manufacturing tolerances," or logical combinations thereof. Finally, directional adjectives and adverbs (such as, head, tail, inside, outside, left, right, vertical, horizontal, up, down, front, back, left, right, and the like) may be relative to the motor vehicle, such as the forward direction of travel of the motor vehicle, when the vehicle is operatively oriented on a level running surface.

[0070] Referring now to the drawings, wherein like reference numerals refer to like features throughout the several views, Figure 1 , a perspective view illustration of a representative automobile is shown, generally designated 10 and depicted herein for purposes of discussion as an engine-propelled sedan-style passenger vehicle. The illustrated automobile 10 (also referred to herein as a "motor vehicle" or simply "vehicle") is merely an exemplary application with which the novel aspects of the present disclosure may be practiced. Similarly, the implementation of the present concepts into a gasoline engine should also be understood as an exemplary application of the novel concepts disclosed herein. Thus, it will be understood that the features of the present disclosure may be applied to other engine configurations, implemented by alternative powertrain architectures, and utilized in logically related vehicle and non-vehicle applications. Finally, selected components of the automobile and internal combustion engine have been shown and will be described in greater detail herein. Nevertheless, the vehicles and engines discussed below may include many additional and alternative features, as well as other available peripheral components for implementing the various methods and functions of the present disclosure.

[0071] Figure 1 An example of a twin cam inline engine assembly 12 is illustrated mounted within an engine compartment 14 of a vehicle body. The illustrated engine assembly 12 is a four-stroke reciprocating piston engine configuration operative to propel the vehicle 10, such as, for example, a direct injection (DI) gasoline engine (including flexible fuel vehicle (FFV) and hybrid electric vehicle (HEV) variants thereof). The engine assembly 12 is selectively operable in a variety of selectable combustion modes, including a homogeneous charge compression ignition (HCCI) combustion mode and an adjustable lift spark ignition (SI) combustion mode. Although in Figure 1 It is not explicitly depicted in the , but it is envisioned that the vehicle driveline can present a variety of available configurations, including a front-wheel drive (FWD) layout, a rear-wheel drive (RWD) layout, an all-wheel drive (AWD) layout, a four-wheel drive (4WD) layout, etc.

[0072] The engine assembly 12 employs a series of reciprocating pistons 16 that slidably move within cylinder bores 15 of the engine block 13. The engine pistons 16 are typically provided in even numbers of 4, 6, 8, etc., and are arranged in a V- or I-type configuration. The top surface of each piston 16 cooperates with the inner periphery of its corresponding cylinder 15 and the corresponding chamber surface 19 of the cylinder head 25 to define a variable volume combustion chamber 17. Each piston 16 is connected to the crankpin ( Figure 2). The crankshaft 11, in turn, converts the linear reciprocating motion of the piston 16 into rotational motion, which is output, for example, as revolutions per minute (RPM) to a power transmission (not shown) to drive one or more road wheels 22. The crankshaft 11 is shown enclosed within a crankcase 23 mounted below the engine block 13. Although shown as separate parts, the engine block 13 and cylinder head 25 may be integrally formed as a one-piece, unitary "monobloc" construction.

[0073] The air intake system delivers intake air to the cylinders 15 via an intake manifold 29, which directs and distributes the air into the combustion chambers 17 via intake runners in the cylinder head 25. The engine's air intake system includes an air flow duct system and various electronic devices for monitoring and regulating the flow of incoming air. As a non-limiting example, the air intake device can include a mass air flow sensor 32 for monitoring mass air flow (MAF) 53 and intake air temperature (IAT) 55. A throttle valve 34 controls the flow of air to the engine assembly 12 in response to a control signal (ETC) 57 from a programmable engine control unit (ECU) 5. A pressure sensor 36 in the intake manifold 29 monitors, for example, manifold absolute pressure (MAP) 59 and barometric pressure.

[0074] An optional external flow passage (not shown) recirculates exhaust gas from the engine exhaust to the intake manifold 29, employing an exhaust gas recirculation (EGR) valve 38 to meter the volume of recirculated exhaust gas directed back into the cylinders 15. The programmable engine control unit 5 controls the mass flow of exhaust gas to the intake manifold 29 by controlling the opening / closing of the EGR valve 38 via an EGR command 61. Figure 1 , the arrows connecting the ECU 5 with the various components of the engine assembly 12 represent electronic signals or other communications exchanges by which data and / or control commands are transmitted from one component to another.

[0075] The flow of air from the intake manifold 29 into the combustion chamber 17 is controlled by one or more intake engine valves 20. Exhaust gas from the combustion chamber 17 to the exhaust manifold 39 is controlled by one or more exhaust engine valves 18. These engine valves 18, 20 are illustrated herein as spring-biased poppet valves; however, other commercially available types of engine valves may be employed. The valvetrain system of the representative engine assembly 12 is equipped to control and regulate the opening and closing of the exhaust engine valves 18 and the intake engine valves 20. Although illustrated as having a single pair of engine valves, it should be understood that each cylinder 15 may be equipped with multiple pairs of intake / exhaust engine valves.

[0076] The activation of the engine valves 18 and 20 can be modulated by controlling the exhaust and intake variable cam phase / variable lift control (VCP / VLC) devices 46 and 48. These VCP / VLC devices 46 and 48 are operable to control the intake camshaft 47 and the exhaust camshaft 49. The rotation of the intake camshaft 47 and the exhaust camshaft 49 is linked and indexed to the rotation of the crankshaft, thereby linking the opening and closing of the intake valve 20 and the exhaust valve 18 to the position of the crankshaft 11 and the piston 16. The intake VCP / VLC device 46 can variably switch and control the valve lift of the intake valve(s) 20 in response to a control signal (iVLC) 63, and variably adjust and control the phase of the intake camshaft 47 for each cylinder 15 in response to a control signal (iVCP) 65. The exhaust VCP / VLC device 48 may variably switch and control the valve lift of the exhaust valve(s) 18 in response to a control signal (eVLC) 67 , and variably adjust and control the phase of the exhaust camshaft 49 of each cylinder 15 in response to a control signal (eVCP) 69 .

[0077] Continue to refer Figure 1 In a representative configuration, the engine assembly 12 employs a DI fuel injection subsystem having a plurality of high-pressure electronic fuel injectors 28 that inject pulses of fuel directly into the combustion chamber 17. As shown, each cylinder 15 is provided with one or more fuel injectors 28, which are activated in response to an injector pulse width command (INJ_PW) 75 from the ECU 5. These fuel injectors 28 are supplied with pressurized fuel via a fuel distribution system. When activated, the fuel injectors 28 are operable to inject multiple fuel pulses per operating combustion cycle into corresponding ones of the engine cylinders 15. The engine assembly 12 employs a compression ignition process (for diesel engine architectures) or a spark ignition process (for gasoline engine architectures), by which fuel combustion initiating energy (such as a sudden electrical discharge provided by the spark plug 26 in response to a spark command (IGN) 71) ignites the cylinder charge in the combustion chamber 17. The fuel injectors 28 may also take the form of an electronically controlled common rail fuel injector architecture that operates in a normally closed solenoid actuated mode of operation.

[0078] The engine assembly 12 is equipped with various sensing devices for monitoring engine operation, including a crank sensor 42 that monitors the rotational position of the crankshaft and outputs a crank angle / speed (RPM) signal 43. A temperature sensor 44 monitors, for example, one or more engine-related temperatures (e.g., coolant temperature, oil, etc.) and outputs a signal 45 indicative thereof. An in-cylinder combustion sensor 30 monitors combustion-related variables such as in-cylinder combustion pressure, charge temperature, fuel mass, air-fuel ratio, etc., and outputs a signal 31 indicative thereof. An exhaust gas sensor 40 monitors one or more exhaust-related variables such as actual air / fuel ratio (AFR), burned gas fraction, etc., and outputs a signal 73 indicative thereof.

[0079] Next go to Figure 2 , a representative crankshaft assembly 111 is shown. The crankshaft assembly 111 may be for vehicle applications such as, Figure 1 The crankshaft 11 in the engine assembly 12 of the present invention is implemented as well as non-vehicle applications such as reciprocating compressors, oil well pumps, etc. For example, the crankshaft assembly 111 includes an elongated, nonlinear crankshaft body 150 that is arranged along a central crankshaft axis A. CR 15. The crankshaft assembly 111 extends about the central crankshaft axis on which it rotates. The crankshaft body 150 is generally defined by: a series of main bearing journals 152; a series of crank pins (or "rod bearing journals") 154 interleaved with the bearing journals 152; a series of crank webs (or "arms") 156 interconnecting the bearing journals 152 with the crank pins 154; and an optional set of counterweights 158 coupled to or integral with selected crank webs 156. As shown, the crankshaft body 150 (including the bearing journals 152, crank pins 154, and crank webs 156) is integrally formed as a one-piece, unitary structure.

[0080] The main bearing journals 152 are coaxially aligned with each other, with each main bearing journal aligned with the crankshaft axis A CR Concentric. On the crankshaft axis A CR During rotation, the main bearing journals 152 may ride on complementary bearing bushings (not shown) that are retained in an engine crankcase (e.g., Figure 1 In the crankcase 23). Figure 2Five main bearing journals 152 are shown as cylindrical structures that share a common width and diameter and are spaced apart from one another along the longitudinal length of the crankshaft body 150. Each bearing journal 152 may have a hollow configuration with an internal journal cavity 151 extending axially through the center of the bearing journal 152. In particular, each optional journal cavity 151 may extend completely through the corresponding main bearing journal 152, with axially spaced cavity openings on both the engine-side (first) axial face and the transmission-side (second) face of the journal 152. Alternative configurations may include more or fewer than five main bearing journals, main bearing journals having structures similar to or different from that shown, and main bearing journals with or without internal cavities or with cavities that are countersunk.

[0081] Continue to refer Figure 2 , the crankshaft assembly 111 may be particularly adapted for an inline four (I4) engine and thus includes four crank pins 154, eight connecting webs 156, and four counterweights 158. Each of the crank pins 154 supports a rod bearing (e.g., a plain bearing housing) thereon and acts as a piston connecting rod (e.g., Figure 1 The connecting rod 21 of the crankshaft assembly 111 attaches the piston (e.g., engine piston 16) to the attachment point of the crankshaft assembly 111. Similar to the main bearing journals 152, the crank pins 154 are spaced apart from each other along the longitudinal length of the crankshaft body 150. Unlike the bearing journals 152, the crank pins 154 are aligned with the crankshaft axis A. CR Instead, the centerline of each crank pin 154 is from the crankshaft axis A CR Radially spaced (ie, "axially offset") such that the crank pins 154 are axially spaced about the crankshaft axis A during rotation of the assembly 111. CR Orbit. As used herein, the term "cavity" may be used to refer to a structural void, including through-holes, countersunk holes, cylindrical hollow cores, recessed cavities, geometrically complementary holes, centerlines, and axially offset cores, among others.

[0082] Each crankpin 154 can be structurally identical, sharing a common cylindrical configuration with a hollow core defined by an internal crankpin cavity 153 extending axially through the center of the crankpin 154. Specifically, each optional crankpin cavity 153 can extend completely through the corresponding crankpin 154, with one cavity opening on the engine-side (first) axial face of the crankpin 154 and another cavity opening on the transmission-side (second) axial face. The crankshaft body 150 can include more or fewer than four rod bearing journals, can include rod bearing journals having a structure similar to or different from that shown, and can include rod bearing journals with or without internal cavities. To this end, the crankshaft assembly 111 can be configured for use with other engine styles and architectures, including: alternative single-bank inline layouts; multi-bank (V) layouts; V- and I-type engines having six, eight, ten, etc. cylinders; or inline and rotary-type engines having three, five, seven, etc. cylinders.

[0083] A series of crank webs 156 physically connect the main bearing journal 152 to the crank pin 154. These crank webs are interleaved with and sandwiched between the journal 152 and the crank pin 154. Each crank web 156 is a spur from the crankshaft axis A to the crankshaft axis B. CR An elliptical structure protruding radially outward from the bearing journal 152 extends to the crank pin 154. These crank webs 156 can be identical in structure to one another, or alternatively, a subset of the crank webs 156 can share one mating configuration, while another subset of the crank webs 156 can share a different mating configuration. As a further option, the eight crank webs 156 and their corresponding crank pins 154 can be aligned along a single plane; otherwise, the crank pins 154 and crank webs 156 can be arranged in multiple planes and thus around the crankshaft axis A. CR Circumferentially spaced. Figure 2 In the crankshaft body 150 , the crank web 156 covers the facing open end of the journal cavity 151 and the open end of the web cavity 155 .

[0084] An internal web cavity 155 extending through the crank web 156 connects the internal journal cavity 151 of the main bearing journal 152 and the internal crankpin cavity 153 of the crankpin 154. Similar to the journal cavity 151 and crankpin cavity 153, each optional web cavity 155 can extend completely through the corresponding crank web 156, with axially opposing cavity openings located on the engine side (first) face and the transmission side (second) face of the crank web 156. Compared to the crankpin cavity 153 and web cavity 155 shown (these cavities have a constant diameter and are parallel to the crankshaft axis A), the internal web cavity 155 of the crank web 156 is connected to the internal journal cavity 151 of the main bearing journal 152 and the internal crankpin cavity 153 of the crankpin 154. CR The centerline "origin" axis of the inner web cavity 155 is relatively close to the crankshaft axis A CRObliquely angled and having a cross-section that varies along the length of the crankshaft body 150 .

[0085] To help alleviate the torsional and shear forces acting on the main bearing journals 152 and thereby improve the expected operational life of the crankshaft support bearings, a set of counterweights 158 may be attached to the crankshaft body 150 and extend radially away from the crankshaft axis A. CR As shown, each counterweight is a semicircular structure integrally formed with a corresponding crank web 156, protruding from the crankshaft body 150 on a side of the crankshaft body 150 opposite the web 156 and its mating crank pin 154. These counterweights 158 help offset the reciprocating mass of the piston, piston rings, piston pin, retaining clip, and upper portion of the connecting rod, as well as the rotating mass of the lower portion of the connecting rod, bearings, and crankshaft assembly 111. Since the crank web 156 is the structural member of the crankshaft body 150 that physically connects the main bearing journals to the rod bearing journals, and the counterweights 158 can be designed to reduce bearing loads and balance engine vibrations, the crankshaft body 150 can have several counterweight structures attached to various sections in any combination.

[0086] As noted above, the crankshaft body 150 is manufactured from a rigid material having a relatively low weight and elastic modulus. For example, the crankshaft body 150 may be formed in whole or in part from aluminum, an aluminum alloy, titanium, or nodular iron.

[0087] Figure 3 The crankshaft 111 is shown along Figure 2 In the illustrated example, the crankshaft 111 includes a distal end portion having a flange 160. The flange 160 includes a flange 160 relative to the axis A. CR The radially outer surface 162 extends from the first axially facing surface 160A to the second axially facing surface 160B, and tapers from the first axially facing surface 160A to the second axially facing surface 160B.

[0088] A gear 164 (such as an oil pump drive gear) is press-fitted onto the flange 160, wherein the radially inner surface 168 of the gear 164 engages the radially outer surface 162 of the flange 160 and the radially outer surface having the helical teeth 166. The gear 164 includes a first axially facing surface 164A and a second axially facing surface 164B. For ease of illustration, Figure 4 The radially outer surface 162 is enlarged. Figure 4 As shown in , radially outer surface 162 includes a conical shape such that it defines a conical gear engaging surface that engages a complementary conical surface on radially inner surface 168 of gear 164 , thereby defining a conical flange engaging surface.

[0089] In the illustrated example, the radially outer surface 162 is parallel to the rotation axis A of the crankshaft 111. CR The line extends at an angle 170 that is greater than or equal to five degrees and less than or equal to fifteen degrees. In one example, radially outer surface 162 does not include a step or protrusion for engaging the axial surface of gear 164, such that radially outer surface 162 of flange 160 includes a continuous ramp or conical shape between first axially facing surface 160A and second axially facing surface 160B. Eliminating steps or protrusions on radially outer surface 162 of flange 160 can reduce stress concentration areas in crankshaft 111 and reduce the rotating mass of crankshaft 111.

[0090] Additionally, when gear 164 includes a set of right-hand helical teeth 166 that drives a gear (not shown) having a set of left-hand helical teeth, the force between the helical teeth biases gear 164 toward the enlarged end of radially outer surface 162 of flange 160. This configuration prevents gear 164 from walking or moving axially along flange 160 during operation of engine assembly 12. Specifically, because the force generated between the pair of helical gear teeth is less than the press-fit force required to move gear 164 along radially outer surface 162 of flange 160, gear 164 is prevented from walking.

[0091] Various aspects of the present disclosure have been described in detail with reference to illustrated embodiments; however, those skilled in the art will recognize that many modifications may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise configuration and components disclosed herein; any and all modifications, changes, and variations apparent from the foregoing description are within the scope of the present disclosure as defined by the appended claims. Furthermore, the present concept expressly encompasses any and all combinations and subcombinations of the foregoing elements and features.

Claims

1. A crankshaft assembly comprising: A crankshaft body extending along a rotation axis, the crankshaft body comprising: a plurality of bearing journals coaxial with the axis of rotation and spaced apart from one another along the length of the crankshaft body; a plurality of crank pins spaced apart from one another along the length of the crankshaft body and axially offset from the axis of rotation; a plurality of crank webs projecting radially from the rotational axis and interconnecting the bearing journals and the crank pin; and A flange extending from a distal end of the crankshaft body has a conical gear engaging surface.

2. The crankshaft assembly according to claim 1, wherein: The conical gear engaging surface tapers toward a distal end of the crankshaft body.

3. The crankshaft assembly according to claim 2, wherein: The conical gear engagement surface extends between five and fifteen degrees relative to the axis of rotation.

4. The crankshaft assembly according to claim 2, wherein: The flange includes a first axially facing surface and a second axially facing surface, and the conical gear engaging surface extends from the first axially facing surface to the second axially facing surface.

5. The crankshaft assembly of claim 2 including a gear having a conical flange engaging surface complementary to the conical gear engaging surface.

6. The crankshaft assembly according to claim 5, wherein: The gear includes helical teeth extending from a radially outer surface of the gear.

7. The crankshaft assembly according to claim 6, wherein: The helical teeth on the gear are right-hand helical teeth.

8. The crankshaft assembly of claim 1, wherein: Each of the plurality of bearing journals defines a journal cavity therein.

9. The crankshaft assembly according to claim 8, wherein: Each of the plurality of crankpins defines a crankpin cavity therein.

10. The crankshaft assembly according to claim 9, wherein: Each of the plurality of crank webs defines a web cavity therein.

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