TAPERED SHAFT HUB ADAPTER

Disclosed embodiments include a pump assembly comprising a pump including a rotating drive shaft having a tapered end portion, a first alignment structure on the drive shaft, and a hub adapter including a first mounting portion comprising a tapered opening and a second mounting portion extending from the first mounting portion and configured to receive a drive member. The tapered opening is configured to be inserted onto and engaged with the tapered end portion of the drive shaft. A second alignment structure is located on the hub adapter, and the first alignment structure and the second alignment structure cooperate to enable a predetermined registration of the hub adapter on the drive shaft. A fastener structure secures the hub adapter to the drive shaft.

TECHNICAL FIELD

This disclosure relates generally to mechanical assemblies including a rotating tapered shaft and structures mounted to the tapered shaft. Embodiments include a hub adapter to couple a gear to a tapered drive shaft of a pump.

BACKGROUND

Mechanical assemblies including tapered shafts and structures mounted to the tapered shafts are generally known and disclosed, for example, by the Alborn U.S. Pat. No. 1,790,737 and the Killingsworth U.S. Pat. No. 2,543,854. These patents disclose axles having tapered end portions, and wheels having hubs. The wheels are mounted to the axles with the hubs inserted onto the tapered end portions of the axles. Nuts engaging threaded ends of the axles secure the hubs to the axles.

High pressure fuel pump assemblies including tapered shafts and drive gears mounted to the tapered shafts are also known. In these assemblies the end portions of the fuel pump drive shafts are tapered and include threaded stubs at their ends. Hubs of the gears have tapered central openings that are inserted onto the tapered end portions of the shafts. Nuts inserted onto the threaded stubs of the drive shafts secure the gears onto the drive shafts. Openings through the gear hubs that are aligned with openings in the drive shafts can receive pins to prevent the gear hubs from rotating on the drive shafts as the nuts are installed.

There remains, however, a continuing need for assemblies including rotating tapered shafts and structures mounted to the shafts. Such assemblies that are efficient to manufacture, assemble and/or service would be especially desirable.

SUMMARY

Disclosed embodiments include assemblies comprising rotating tapered shafts and structures mounted to the shafts. The assemblies are efficient to manufacture, assemble and/or service.

One example is an assembly comprising a rotating shaft having a tapered end portion; a hub adapter including a first mounting portion comprising a tapered opening and a second mounting portion extending from the first mounting portion and configured to receive a drive member, wherein the tapered opening is configured to be inserted onto and engaged with the tapered end portion of the rotating shaft; and an adapter fastener structure to secure the hub adapter to the rotating shaft.

In embodiments, the fastener structure comprises a threaded stub on the tapered end portion of the rotating shaft, wherein the threaded stub extends through the opening of the hub adapter; and a threaded nut installed on the threaded stud.

Embodiments further include a first adapter alignment structure on the hub adapter; and a second adapter alignment structure on the rotating shaft, wherein the first adapter alignment structure and the second adapter alignment structure cooperate to enable a predetermined registration of the hub adapter on the rotating shaft. The first adapter alignment structure may include a keyway; and the second adapter alignment structure may include a pin receivable by the keyway. In embodiments, the first adapter alignment structure includes a first alignment opening extending through a portion of the hub adapter and into the tapered opening; the second adapter alignment structure includes a second alignment opening extending into the tapered end portion of the rotating shaft, wherein the first and second adapter alignment openings can be aligned; and the assembly further includes a pin extending between the first alignment opening and the second alignment opening.

In embodiments, the first mounting portion of the hub adapter further includes a flange extending into the tapered opening and configured to engage the tapered end portion of the rotating shaft. The tapered end portion of the rotating shaft may include a shoulder; and the flange of the hub adapter may engage the shoulder of the rotating shaft.

Embodiments may further comprise a drive structure (e.g., a drive or driven member) mounted to the second mounting portion of the hub adapter. The drive structure may comprise a gear. Embodiments further comprise one or more drive fastener structures to secure the drive structure to the second mounting portion of the hub adapter. The one or more drive fastener structures may comprise a threaded opening in the second mounting portion of the hub adapter; and a threaded bolt inserted in the threaded opening. In embodiments, the drive structure includes an opening aligned with each threaded opening in the second mounting portion; and each threaded bolt extends through an associated opening in the drive member and into engagement with the drive member. Embodiments may also include a plurality of the drive member fastener structures at circumferentially spaced-apart locations on the second mounting portion around the tapered opening. Embodiments may further include a first location opening extending through the drive structure; a second location opening extending into the second mounting portion of the hub adapter, wherein the first and second location openings can be aligned; and a locating pin extending between the first location opening and the second location opening.

Embodiments of the assembly include a high pressure pump such as a fuel pump and the rotating shaft is a high pressure pump drive shaft. The drive structure may comprise a gear.

Another example is a pump assembly, comprising a pump including a rotating drive shaft having a tapered end portion; a first alignment structure on the drive shaft; a hub adapter including a first mounting portion comprising a tapered opening and a second mounting portion extending from the first mounting portion and configured to receive a drive member, wherein the tapered opening is configured to be inserted onto and engaged with the tapered end portion of the rotating shaft; a second alignment structure on the hub adapter, wherein the first alignment structure and the second alignment structure cooperate to enable a predetermined registration of the hub adapter on the rotating shaft; and a fastener structure to secure the hub adapter to the rotating shaft.

In embodiments, the first alignment structure includes a pin; and the second alignment structure includes a keyway receivable by the pin. Embodiments may further include a registration structure on the hub adapter to enable a predetermined registration of a drive member to the hub adapter. A drive member may be mounted to the hub adapter, and may comprise a gear.

Embodiments of the assembly further include a gear registration structure on one or both of the hub adapter and the gear to enable a predetermined registration of the gear to the hub adapter. The gear registration structure may include asymmetrically located fastener-receiving openings on one or both of the gear and the hub adapter.

Embodiments of the pump assembly are configured for mounting to an engine block; and the hub adapter further comprises alignment indicia for enabling alignment of the hub adapter to the engine block. Embodiments may include alignment indicia on the gear for enabling alignment of the gear.

DETAILED DESCRIPTION

FIG.1andFIG.2illustrate a tapered shaft hub adapter10in accordance with embodiments of a first example incorporated into an application or assembly including a high pressure pump12having a tapered drive shaft14.FIG.1is an isometric illustration of the high pressure pump12, showing the hub adapter10mounted to the tapered drive shaft14of the pump.FIG.2is a cross sectional illustration of the tapered drive shaft14and hub adapter12, showing a drive gear15mounted to the hub adapter in accordance with embodiments. In embodiments, the high pressure pump12is a fuel pump. Other embodiments include tapered shaft hub adapters such as10incorporated into other applications or assemblies, such as for example assemblies including alternators and vehicle axles. Other embodiments may include other drive or driven structures (e.g., other than drive gears such as15) mounted to the hub adapters, such as for example pulleys or wheels.

As perhaps best shown inFIG.2, drive shaft14includes a tapered end portion16defining an outer surface17. The end portion16tapers in a direction of reduced diameter with increasing distance toward the end of the drive shaft. The tapered end portion16of the drive shaft14defines a shoulder18. In the illustrated embodiments the shoulder18is located at an end of the tapered end portion16. Embodiments of tapered drive shaft14include a threaded stub20. In the illustrated embodiments the threaded stub20extends from tapered end portion16of the drive shaft14(e.g., beyond the shoulder18). As described in greater detail below, the threaded stub20forms part of a fastener structure used to secure the drive shaft14to the hub adapter10in embodiments. Drive shaft14may be mounted for rotation on the high pressure pump12in a conventional manner.

Tapered hub adapter10includes a first or shaft mounting portion30and a second or drive mounting portion32that is peripheral to the shaft mounting portion. The shaft mounting portion30includes a tapered surface34defining a tapered opening36. The tapered opening36tapers in a manner that is complimentary to the taper of the tapered end portion16of the drive shaft14. The tapered surface34of the hub adapter10is thereby configured to mate with and engage the tapered end portion16of the drive shaft14.

Drive mounting portion32includes portions extending circumferentially around the shaft mounting portion30. In the illustrated embodiments the drive mounting portion32is continuous. Drive mounting portion32is configured to receive the drive gear15(or other drive or driven structures in other embodiments). In the illustrated embodiments the drive mounting portion32includes a plurality of threaded openings40at circumferentially spaced-apart locations. As described in greater detail below, the threaded openings40form part of a fastener structure used to join the hub adapter10to the drive gear15in embodiments. Embodiments of the hub adapter10include a location opening42extending into the drive mounting portion32on a side opposite the side facing the high pressure pump12. As described in greater detail below, the location opening42may be used to join the hub adapter12and drive gear15.

Tapered hub adapter10is assembled onto the high pressure pump12by sliding the shaft mounting portion32over the drive shaft14(i.e., with the tapered end portion16of the drive shaft extending into the tapered opening36of the hub adapter). The tapered surface34of the hub adapter10thereby engages the surface17of the tapered end portion16of the drive shaft14for a friction fit. With the hub adapter10mounted on the drive shaft14, the threaded stub20of the drive shaft will extend through the tapered opening36of the mounting portion30. A threaded nut46can be inserted onto the threaded stub20to secure the hub adapter10to the drive shaft14. In other embodiments, other fastener structures are used to secure the hub adapter10to the drive shaft14(e.g., a bolt screwed into a threaded opening in the drive shaft14).

Drive gear15can be assembled onto the drive mounting portion32of the hub adapter10. Embodiments of the drive gear15may include a location opening (not shown) that extends through the gear (i.e., in a direction generally perpendicular to the rotational axis of the gear). The location opening is positioned on the drive gear15to align with the location opening42in the hub adapter10when the drive gear is properly located on the hub adapter. In embodiments that include the location opening in the drive gear15and location opening42in the hub adapter10, the location openings may be aligned, and a dowel pin (not shown) inserted into or through the location openings with portions of the pin extending into both the gear and hub adapter to locate the gear and hub adapter with respect to one another. Drive gear15includes openings48that extend through the gear and are aligned with the threaded openings40in the hub adapter10. Threaded bolts50are inserted though the openings48and into corresponding threaded openings40in the hub adapter10to secure the drive gear15to the hub adapter. In other embodiments, other fastener structures are used to secure the drive gear15to the hub adapter10(e.g., treaded studs extending from the hub adapter through holes in the drive gear, with threaded nuts on the studs).

Hub adapters such as10may provide important advantages. For example, they can couple torque between a drive or driven source and a drive shaft (e.g., from a gear train to a high pressure pump in the illustrated embodiments). Flat drive members such as the drive gear can be effectively coupled to tapered shafts. Serviceability of the drive source-to-drive shaft joint is enhanced as the bolts or other fasteners that secure the gear or other drive structure to the hub adapter may have lower nominal torque than a single nut (e.g., if the drive gear is mounted directly to the drive shaft). It allows the drive gear or other drive member to be removed and serviced without servicing the tapered drive shaft joint. It may also prevent field related issues to slip issues from servicing the taper joint by making the taper a non-service item installed during the driven member (e.g., high pressure pump) assembly.

FIG.3andFIG.4illustrate a tapered shaft hub adapter110in accordance with embodiments of a second example incorporated into an application or assembly including a high pressure fuel pump112having a tapered drive shaft114. A portion of a drive gear115is shown mounted to the hub adapter110. As described in greater detail below, hub adapter110includes indicia and structure that register and/or cooperate with other indicia and structures to enable the proper timing of the pump112with other structures of the engine block. With the exception of the features and/or differences described below, features of hub adapter110, pump112, tapered drive shaft114and drive gear115may be substantially the same as or similar to those of hub adapter10, pump12drive shaft14and gear15described above in connection withFIGS.1and2, and similar features are identified by similar reference numbers in the “lxx” series.

As shown inFIGS.3and4, the tapered shaft114of the pump112includes a dowel pin160extending from the surface117of the shaft. Dowel pin160is located at a predetermined position about the outer circumference of the shaft114and functions as a registration indicia with respect to the operating stroke of the pump112. Tapered shaft hub adapter110includes an elongated slot or keyway162in the surface134of the opening136. The keyway162is sized to receive the dowel pin160when the hub adapter is slid or otherwise assembled onto the shaft114of the pump112. The location of the keyway162is registered to other features on the hub adapter110, such as the threaded openings140and alignment mark164on the end face of the drive mounting portion132of the hub adapter. Keyway162thereby functions as a registration indicia that cooperates with the dowel pin160to register the hub adapter110to a predetermined position about the rotational axis on the tapered shaft114. Because of the registration provided by the dowel pin160and keyway162, the locations of features of the hub adapter110, such as the threaded openings140and alignment mark164, are registered to the operating stroke of the pump112.

The illustrated embodiments of tapered shaft hub adapter110also include one or more structures shown as openings or notches166(two are shown). The notches166function as structures on the hub adapter110that can be engaged by tooling (not shown) during the assembly or installation of the hub adapter onto the pump112to radially hold the hub adapter with respect to the pump and resist torque. In the illustrated embodiments the notches166are shown on the peripheral edge of the drive mounting portion132of the hub adapter110. As shown inFIG.5, the notches166are recesses in the outer peripheral edge of the hub adapter110, and have a depth that is less than the full thickness of the hub adapter at the location of the notches. The notches166thereby extend into a partial depth of the hub adapter110. By this structure and location, the notches166may minimize or block debris from possible failures of the fuel pump112from being transferred to the gear115or other adjacent components such as the gear train. Alternatively or in addition, other embodiments include other structures, and/or such structures at different locations on the hub adapter110, to provide the functionality of the notches166.

In embodiments, the hub adapter110and/or gear115are configured so that the gear can be installed or assembled onto the hub adapter in a matter that registers or times the position of the gear on the hub adapter (and thereby to the operating stroke of the pump112). In the embodiments shown inFIGS.6A and6B, for example the threaded openings140in the hub adapter110are asymmetrically positioned about the hub adapter so that the gear115(not shown inFIGS.6A and6B), which includes openings148(FIG.7) corresponding to the threaded openings in the hub adapter, can be installed on the hub adapter in only one position. In the embodiments shown inFIG.6A, for example, one of the threaded openings140is circumferentially spaced from adjacent openings by 50° and 70°, while the other threaded openings are spaced from one another by 60°.

FIGS.6A and6Billustrate the hub adapter110extending though an opening in an engine block170after the pump112(not visible inFIGS.6A,6B) is mounted to the engine block.FIG.7is a view of the hub adapter110/pump112/engine block170assembly shown inFIGS.6A and6B, illustrating also the drive gear115mounted to the hub adapter (which is not generally visible inFIG.7). As shown inFIG.6B, the angle between the keyway162and the alignment mark164are controlled so that the alignment mark is horizontal when the tapered shaft114of the pump112is timed or registered at the proper angle. The embodiments shown inFIGS.6A and6Binclude an alignment mark172on the engine block170that can be located with respect to the alignment mark164on the hub adapter110to indicate proper registration or timing of the hub adapter. In the illustrated embodiments, the alignment mark172on the engine block170is located to identify the desired horizontal position of the alignment mark164on the hub adapter110. Alignment marks164and172are etched onto the hub adapter110and engine block170in embodiments. In other embodiments other structures and/or other positional locations of the structures may be used to indicate the desired timing or registration between the hub adapter110and engine block170.

The embodiments of drive gear115illustrated inFIG.7include a plurality of alignment marks176, which may, for example, be marks etched onto the gear. Alignment marks176function as indicia to indicate the proper timing or registration of the pump112. In the embodiments illustrated inFIG.7, for example, the alignment marks176will be oriented horizontally when the pump112is properly timed. Other embodiments include other indica, and/or locations of such indica on the drive gear115, to indicate that the fuel pump112is installed and timed properly. The embodiments of drive gear115shown inFIG.7also includes threaded holes178that are configured to removably receive threaded studs or bolts (not shown) that can be used as grips to aid with the assembly and/or removal of the drive gear with respect to the hub adapter110.

Embodiments of hub adapter110, pump112and gear115offer important advantages. For example, the hub adapter110may be installed on the pump112to form an assembly during a first manufacturing operation (e.g., by a first entity), and later assembled onto the engine block170during a second manufacturing operation (e.g., by a second entity). The assembly including the pump112and hub adapter110can thereby be efficiently assembled onto the engine block170. Similarly, the drive gear115can be efficiently assembled onto the assembly of the pump112and hub adapter110. The timing and registration indicia and features, such as the dowel pin160and keyway162, asymmetrically arranged openings140on the hub adapter110and corresponding openings148on the drive gear115, and alignment indicia164,172and176, enable the efficient and effective timing or registration of the pump112to the drive gear115and/or other drive train components during the assembly process.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. For example, it is contemplated that features described in association with one embodiment are optionally employed in addition or as an alternative to features described in connection with another embodiment. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.