CRANKTRAIN PHASE ADJUSTER FOR VARIABLE COMPRESSION RATIO

A phase adjuster is disclosed herein that generally includes multiple stamped components and limits threaded connections between components. According to one aspect, this configuration provides a cost-effective arrangement in which a drive nut can adjust a phase between an input gear and an output gear.

TECHNICAL FIELD

This disclosure is generally related to a cranktrain phase adjuster that can vary a compression ratio of an internal combustion (IC) engine.

BACKGROUND

Variable compression ratio (VCR) adjustment in IC engines is generally used in order to achieve greater efficiency and improved fuel consumption than an engine with a fixed compression ratio. VCR adjustment systems can rely on a variety of structures and configurations to vary the compression ratio.

Known VCR adjustment systems are typically complicated to integrate with the engine components or require significant space to be installed. Additionally, VCR adjustment systems typically include parts that include threaded engagement interfaces, which require time-consuming assembly and are expensive.

It would be desirable to provide an affordable and compact phase adjuster assembly for a cranktrain to implement VCR in an IC engine.

SUMMARY

In one aspect, a phase adjuster for an internal combustion engine is disclosed. The phase adjuster can include an input gear assembly having an input gear threading and a base body. In one aspect, a drive plate is provided that includes a first radially extending flange connected to the base body. The drive plate has an axially extending portion arranged radially inward from the base body, and the axially extending portion includes a spline configured to transmit torque to a drive nut. In one aspect, a support plate is provided that includes a second radially extending flange connected to the base body. At least one first fastener connects the base body, the first radially extending flange, and the second radially extending flange to each other. The drive plate and the support plate are preferably formed from stamped sheet metal. The drive plate further comprises a stop element that is configured to limit axial movement of the drive nut, in one aspect.

The drive nut includes a groove on a radially outer surface configured to engage with a piston assembly. The piston assembly includes a piston plate having a protrusion configured to engage with the groove on the drive nut to provide a non-threaded connection between the piston assembly and the drive nut. The piston plate is also formed from stamped sheet metal.

An output assembly is also disclosed herein that includes a first output housing and a second output housing connected via at least one fastener. An output gear is arranged radially inside of the second output housing.

The input gear assembly also includes an input housing supported on the base body via a first bearing and a second bearing. The first bearing is axially supported against a shoulder of the base body, and the second bearing is a thrust bearing engaging an axial end face of the base body.

A seal plate can be provided that is fixed to the input housing. The seal plate is formed from stamped sheet metal and partially defines a hydraulic fluid chamber. A seal can be arranged between the seal plate and the piston plate. An oil control valve (OCV) housing assembly is fixed to the seal plate and the input housing via at least one fastener.

In another aspect, the phase adjuster includes an input gear and an output gear, a drive plate including a spline, and a drive nut configured to transmit torque from the input gear to an output gear via engagement with the spline of the drive plate. The spline of the drive plate is configured to limit axial movement of the drive nut. The drive nut is engaged with a piston plate via a radial protrusion formed on the piston plate, in one aspect.

Additional embodiments described below and in the claims.

DETAILED DESCRIPTION

Certain terminology is used in the following description for convenience only and is not limiting. The words “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from the parts referenced in the drawings. “Axially” refers to a direction along the axis of a shaft. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, or c, or combinations thereof. This terminology includes the words specifically noted above, derivatives thereof and words of similar import.

FIGS. 1 and 2are perspective views of a phase adjuster100. The phase adjuster100can be used in internal combustion engines. More specifically, the phase adjuster100can be implemented with a cranktrain200. A schematic diagram is shown inFIG. 11that shows the phase adjuster100installed relative to a cranktrain200including a crankshaft190, and an eccentric shaft180. The phase adjuster100is generally configured to adjust phasing between the crankshaft190and the eccentric shaft180.FIG. 11is a schematic drawing and the exact positioning of components relative to each other can vary. The phase adjuster100is operatively connected to both the crankshaft190and the eccentric shaft180. This connection or interface between the phase adjuster100and the crankshaft190and eccentric shaft180can be achieved in a variety of ways. Additionally, the phase adjuster100can be arranged between different driving components and driven components besides a crankshaft and an eccentric shaft. In one aspect, the phase adjuster100has a gear train configured to operatively connect the crankshaft190to the eccentric shaft180. The gear train can comprise gears1,12,180a,190awhich are shown inFIG. 11for illustrative purposes. The ratio and sizing of the gears1,12,180a,190acan vary. Other driving engagements can be provided.

FIG. 3is a cross-sectional view taken along line A-A fromFIG. 1. As shown inFIG. 3, torque or power input from an internal combustion engine, electric motor, or any other input source enters the phase adjuster100through an input gear1. In one aspect, the input gear1can be in driving engagement with a crankshaft. One of ordinary skill in the art would understand from the present disclosure that other driving arrangements can be provided.

The input gear1is generally part of an input gear assembly5. The input gear1includes an input gear threading1aand a base body1b. The input gear1is secured to a drive plate3and a support plate4via at least one fastener2. In one aspect, the at least one fastener2includes a plurality of rivets. Other types of fastening means can be used. The input gear assembly5is shown in more detailFIGS. 6A and 6B.

In one aspect, the drive plate3and the support plate4are formed from stamping. Specifically, the drive plate3and the support plate4are formed from stamped sheet metal, in one aspect. This provides for a more affordable and cost-effective input configuration.

The drive plate3includes a radially extending flange3aconnected to the base body1b. The drive plate3also includes an axially extending portion3barranged radially inward from the base body1b. The support plate4includes a radially extending flange4athat is connected to the base body1bof the input gear1. As shown inFIG. 3, the at least one fastener2is configured to connect the base body1b, the radially extending flange3aof the drive plate3, and the radially extending flange4aof the support plate4as a singly unitary component.

As shown in more detail inFIG. 6A, the drive plate3includes an integrally formed spline6, which is configured to transmit engine torque to a drive nut7. The spline6is formed on the axially extending portion3bof the drive plate3. The drive plate3is also configured to permit axial motion of the drive nut7along the length of the spline6. The spline6can easily be formed via deformation of the drive plate3due to it being formed from stamped sheet metal.

As shown inFIGS. 3 and 6B, the drive nut7has an internal helical gear8on a radially inner surface that is configured to transmit engine torque into an output shaft9. The output shaft9likewise includes an external helical gear10configured to mate with the helical gear8of the drive nut7.

At least one stop element55can be provided on the drive plate3that is configured to axially secure the drive plate3with the drive nut7, as shown inFIGS. 6C and 6D. In one aspect, the stop element55comprises a pocket, slot, or other feature having an enclosure dimensioned to receive a portion of the drive nut7. In one aspect, a back or rear edge7cof the drive nut7is engaged with the stop element55.

As shown in at leastFIGS. 4A and 4B, the external helical gear10that is configured to engage with the drive nut7is formed on a terminal axial end of the shaft9. In one aspect, the output shaft9is press fit and secured by a weld (i.e. connection interface11) to an output gear12to form an eccentric output assembly13, as shown inFIGS. 4A and 4B. The output gear12is formed separately from the output shaft9, in one aspect. The output gear12is configured to transmit torque out of the phase adjuster100, such as to the eccentric shaft180. Additional details of the output shaft9are provided herein.

FIGS. 10A and 10Bprovide details regarding an oil control valve (OCV)14. In one aspect, the OCV14is mounted in an OCV housing assembly15, and is configured to maintain a pressure balance between an advance port16and a retard port17. The advance port16is connected to an advance oil chamber18and the retard port17is connected to a retard oil chamber19, as shown inFIG. 3. These two chambers18,19are separated by a piston assembly20.

Additional details of the piston assembly20are shown inFIGS. 8A and 8B. The piston assembly20can include a piston plate21that generally divides the wo chambers18,19. In one aspect, the piston plate21is formed from stamped sheet metal. The piston plate21is secured to a clip seal plate23via at least one fastener22. In one aspect, the at least one fastener22includes a plurality of rivets. In one aspect, the rivets are formed from the same material as the piston plate21itself (i.e. extruded rivets). In another aspect, the rivets22are separately formed. At least one seal24is arranged between the piston plate21and the clip seal plate23. The piston plate21generally includes an axially extending flange21aand a radially extending flange21b. As shown inFIG. 8B, the axially extending flange21aincludes a protrusion25configured to engage with the drive nut7. The radially extending flange21bincludes an interface surface configured to engage with the clip seal plate23and the at least one seal24. The at least one seal24ensures that the chambers18,19remain separated and sealed from each other. As shown inFIG. 8B, the at least one seal24can include a radially outer seal24aand a radially inner seal24h, both of which are secured between the piston plate21and the clip seal plate23.

To adjust a phase of the output gear12relative to the input gear1, the OCV14provides hydraulic fluid pressure to either the advance or retard ports16,17causing a higher pressure on one side of the piston assembly20(i.e. in either one of the chambers18,19), which causes the piston plate21to move in that direction.

The piston assembly20, and more specifically the piston plate21, is connected to an axial end of the drive nut7via the protrusion25engaging within a groove7aformed on the drive nut7, and thus allowing the hydraulic pressure force to be transmitted in either direction into the drive nut7. In one aspect, the groove7ais formed on a radially outer surface of the drive nut7. The groove7acan include a single indentation or recess. The connection between the piston assembly20and the drive nut7is provided without any threaded connections, which simplifies the machining and formation of the respective portions required to connect the drive nut7with the piston assembly20. Formation of the protrusion25only requires a simple deformation process in which the protrusion25is deformed radially inward. One of ordinary skill in the art would understand that the protrusion25could also be deformed radially outward to engage with a groove7aformed on a radially inner surface of the drive nut7.

As shown inFIG. 6B, the drive nut7includes a radially outer spline7bthat mates with the spline6of the drive plate3. As the drive nut7is pushed via movement of the piston plate21, the drive nut7imparts a force on the output shaft9through the helical gear8. The contact between the helical gear8and the helical gear10causes a twisting force to develop on the output shaft9which rotates the output shaft9relative to the drive nut7, and thus relative to the input gear1.

As shown in more detail inFIG. 6B, a spring26is contained within a retainer27that compresses between the drive nut7on a first axial side and the support plate4on a second, opposite axial side. The spring26provides an opposing force to the piston assembly20to ensure the piston assembly20is biased in the retard direction. Based on this configuration, the default condition is set to a maximum compression ratio. Due to spring26, less pressure bias is required to retard the piston assembly20as compared to advancing the piston assembly20. In one aspect, the spring26opposes the axial force generated by the torque actin through the helical gears on the drive nut and output shaft9. As torque increases, the force or travel of the spring also increases. Accordingly, the spring26effectively operates to balance the force such that a certain phasing position for a given input torque is maintained. The hydraulic force therefore either adds or subtracts from this force balance to bias the system one way or another, to advance or retard depending on the different phasing position. One of ordinary skill in the art would understand that other configurations may be implemented relative to the piston assembly20.

As shown in more detail inFIG. 5B, the eccentric output assembly13, which includes the output shaft9and the output gear12, is generally supported on a first bearing28and a thrust washer29relative to an output housing30a,30b. The output housing30a,30bcan be comprised of a first output housing30aand a second output housing30b. As shown inFIG. 5B, the output gear12is arranged entirely radially inside of the second output housing30b. The eccentric output assembly13and both output housings30a,30btogether form an output housing assembly35.

As shown inFIG. 5B, the first bearing28is supported between the first output housing30aand the output shaft9, and the thrust bearing29is supported between the first output housing30aand the output gear12. The first and second output housings30a,30bare secured to each other via at least one fastener31. In one aspect, the at least one fastener31includes a plurality of rivets, as shown inFIG. 5A.

In one aspect, the second output housing30bis a stamped sheet metal. As shown inFIG. 5A, an opening33, such as a slot or window, can be defined on the second output housing30b. The opening33is configured to allow a gear connection to the output gear12.

A series of bearings, such as bearings34,36,37,38,39, etc., are provided in one aspect to provide varying support configurations in both the radial and axial direction. While these bearings may be illustrated as spherical ball bearings or thrust bearings in specific locations in the drawings, one of ordinary skill in the art would understand that the exact shape, type, location, and/or orientation of these bearings can vary. A bearing34can be arranged between an axially extending flange of the second output housing30band the support plate4. As shown inFIG. 6B, the input gear assembly5includes a bearing36arranged between the support plate4and the output shaft9. The bearing36can be configured to center the support plate4relative to the output shaft9. A bearing37, which may be a thrust bearing, can be arranged between an axial end of the support plate4and the output gear12. This bearing37provides a thrust path between the input gear assembly5and the eccentric output assembly13. A bearing38can be arranged between an axially extending flange of a base body1bof the input gear1(i.e. base body1b) and an input housing40. In one aspect, the bearing38is axially secured via a shoulder formed on the base body1bof the input gear. The input housing40can include a radially extending portion40aand an axially extending portion40b. A bearing39, which may be a thrust bearing, is arranged between an axial end face of the base body1bof the input gear1and the input housing40. The thrust bearing39can be arranged against the radially extending portion40aand the axial end of the base body1bof the input gear1.

The input housing40is secured by at least one fastener41to a seal plate42to form an input housing assembly43. In one aspect, the seal plate42is formed as stamped sheet metal. The at least one fastener41can include a plurality of rivets, in one embodiment. As shown inFIG. 3, at least one fastener44is configured to connect the OCV housing assembly15to the input housing assembly43. The at least one fastener44can include a plurality of bolts, in one aspect. The at least one fastener44extends between and connects the OCV housing assembly15, the seal plate42, and the input housing40.

The input housing assembly43is shown in more detail inFIGS. 7A and 7B. As shown inFIGS. 7A and 7B, at least one alignment element45can be provided that extends between the input housing assembly43and the OCV housing assembly15. In one aspect, the at least one alignment element45includes a plurality of pins.

As shown inFIGS. 1 and 2, the OCV housing assembly15, the output housing assembly35, and the input housing assembly43are all configured to be secured to the engine via fasteners46. The fasteners46can be bolts, in one arrangement.

FIG. 3illustrates a lubrication path47configured to direct oil from the center of the output shaft9to various locations throughout the entire assembly. The lubrication path47can include an inlet on an axial end face (i.e. the leftmost end inFIG. 3) of the output shaft9. For example, cross-drilled holes48can be provided in the output shaft9and can be configured to supply oil to any one or more of the bearings28,34,36,37, as well as the meshing or gear of the output gear12.

Oil can also pass all the way through the output shaft9, the holes48, and any of the bearings, such that the oil reaches the input gear assembly5, including the meshing or gear of gear1and other bearings, such as bearing38.

At least one drain hole49can be provided in the OCV housing assembly15at an opposite axial end as an inlet for the lubrication path47. The drain hole49is configured to drain oil from the lubrication path47. The drain hole49connects with a recirculation port50of the OCV14at a cross-drilled fluid junction51before draining out of the OCV14back to an oil sump through a drain hole52.

The recirculation circuit allows oil or hydraulic fluid to be provided back into the OCV14from the advance and retard ports16,17due to torque fluctuations, and to drain out of the system.

As shown inFIGS. 3, 10A, 10B, a plurality of plugs53are configured to prevent oil leakage out of the OCV housing assembly15through the ends of the plurality of cross-drilled holes in the OCV housing assembly15. A seal54can be provided that is mounted to the seal plate42and separates the pressurized retard oil chamber19from the rest of the assembly.

In one aspect, a method of assembling the phase adjuster100is provided. Multiple steps are described herein. One of ordinary skill in the art would understand that any one or more of the steps can be modified. Additionally, any one or more other steps may be required that are not explicitly described with respect to the method but are otherwise disclosed in this disclosure.

The phase adjuster100can be assembled by arranging the drive nut7and the spring26inside of the drive plate3. The drive nut7is then compressed against the spring26while the at least one stop element55in the drive plate3is formed to capture the drive nut7within. The at least one stop element55can be formed by a simple deformation process. This step helps retain the drive nut7and prevents the drive nut7from falling out of the input gear assembly5.

The output housing assembly35is then connected to the assembly by inserting the output shaft9into the helical gear8of the drive nut7until the output gear12engages with (i.e. bottoms out on) the thrust bearing37mounted to the support plate4.

Next, a fastener57, such as a bolt, and a retainer washer56are arranged on an axial end of the output shaft9to retain the output housing assembly35to the input gear assembly5. The input housing assembly43is then engaged around and onto the bearings38,39such that the input housing assembly43is supported on the input gear assembly5. In one aspect, the central fastener57can be omitted and other fastening arrangements can be used.

The piston assembly20is then arranged inside of the seal plate42and onto the drive nut7. At least a portion of the piston plate21(i.e. protrusion25) is then deformed into the groove7ain the drive nut7so that the drive nut7and the piston plate21remain connected. Finally, the OCV housing assembly15is bolted to the end of the input housing assembly43.

One of skill in the art would understand from the present disclosure that the phase adjuster100could include any variety or type of rolling element bearings. For example, the thrust bearings and ball bearings could be replaced with angular contact ball bearings capable of handling radial and axial loads.

In another aspect, the OCV housing assembly15can be connected to a remainder of the phase adjuster via an internally recirculating valve.

The embodiments disclosed herein provides a cost-effective configuration that incorporates multiple stamped sheet metal components, which are more cost-effective and affordable than cast formed components.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments that may not be explicitly described or illustrated.

Having thus described the present embodiments in detail, it is to be appreciated and will be apparent to those skilled in the art that many physical changes, only a few of which are exemplified in the detailed description of the disclosure, could be made without altering the inventive concepts and principles embodied therein.

It is also to be appreciated that numerous embodiments incorporating only part of the preferred embodiment are possible which do not alter, with respect to those parts, the inventive concepts and principles embodied therein.

The present embodiment and optional configurations are therefore to be considered in all respects as exemplary and/or illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than by the foregoing description, and all alternate embodiments and changes to this embodiment which come within the meaning and range of equivalency of said claims are therefore to be embraced therein.

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