Reusable dust cap for a pulley assembly

A dust cap for sealing engagement with an opening of a member is disclosed. The dust cap is removable from the opening of the member by a tool. The dust cap includes a body and an elastomeric portion. The body defines an outer perimeter, an inner surface, an outer surface, and a recess disposed along the outer surface. The recess is shaped to receive a portion of the tool. The elastomeric portion is located around the outer perimeter of the body. The elastomeric portion is sealingly engageable with the opening of the body member.

TECHNICAL FIELD

The present invention relates generally to a dust cap that sealing engages with an opening of a pulley assembly, and more particularly to a reusable dust cap.

BACKGROUND

Pulleys such as drive pulleys (both front-side and back-side), idler pulleys, and tensioner pulleys may be used in a vehicle. Specifically, these pulleys may be used to drive or tension a belt of a drive system. The belt drive system may include a driver pulley and one or more idler pulleys, as well as an endless belt. The pulleys may each include a pulley shell or body having a belt-engaging surface. The endless belt is trained around the belt-engaging surface of each pulley shell.

Each pulley may also include one or more bearings that may be located within a bore of the pulley shell. Sometimes contaminants such as, for example, dust, sand, salt or mud may enter the bearings. These contaminants may increase wear and reduce the life of the bearing. Thus, a dust cap or cover may be provided to substantially prevent contaminants from entering the bore of the pulley body. For example, some types of dust caps may be constructed of plastic. However, these types of plastic dust caps typically have cutouts or other openings that allow dirt and other contaminants to enter the bore of the bearing shell.

Some other types of dust covers currently available may be constructed of a metallic material, such as steel. These types of metallic dust caps substantially prevent the contaminants from entering the bore of the pulley body. However, metallic dust caps may require a relatively high installation force, making these types of dust caps difficult to install. Moreover, these types of metallic dust caps may sometimes damage or puncture the bearing race located within the pulley body during the removal process. Finally, metallic dust caps are typically destroyed when removed from the pulley body.

Other types of dust caps may have a metallic body and an over-molded layer of rubber to act as a seal barrier. These over-molded types of dust caps may be easier to install when compared to a metallic dust cap without the over-molded layer of rubber. However, these over-molded dust caps also have drawbacks as well. For example, the over-molded dust caps are not reusable. Specifically, these over-molded dust caps include a central, rubber portion that is punctured during removal of the over-molded dust cap from the pulley body. Moreover, these over-molded dust caps may be easily damaged during shipping. Thus, the over-molded dust cap typically needs to be shipped separately from the pulley body. Therefore, there exists a need for an improved dust cap for a pulley assembly that overcomes the above-mentioned drawbacks.

SUMMARY

A reusable dust cap is disclosed. In one approach, the dust cap may be used to seal a bore of a rotatable member. For example, the dust cap may be used to seal the bore of a pulley assembly for an accessory drive system.

In one embodiment, a dust cap for sealing engagement with an opening of a member is disclosed. The dust cap is removable from the opening of the member by a tool. The dust cap includes a body and an elastomeric portion. The body defines an outer perimeter, an inner surface, an outer surface, and a recess disposed along the outer surface. The recess is shaped to receive a portion of the tool. The elastomeric portion is located around the outer perimeter of the body. The elastomeric portion is sealingly engageable with the opening of the body member.

The tool may be used by an operator during removal of the dust cap from the opening of the member. Specifically, the dust cap may be removed from the opening without any substantial deformation or damage to either the body or the elastomeric portion of the dust cap. Thus, the dust cap may be manually installed and subsequently removed from the opening multiple times. In other words, the recess enables the dust cap to be reusable.

In another embodiment, a rotatable assembly is disclosed. The rotatable assembly includes a rotatable member having a bore therethrough where the bore defines an opening, and a dust cap. The dust cap is removable from the opening of the member by a tool. The dust cap includes a body and an elastomeric portion. The body defines an outer perimeter, an inner surface, an outer surface, and a recess disposed along the outer surface. The recess is shaped to receive a portion of the tool. The elastomeric portion is located around the outer perimeter of the body. The elastomeric portion is sealingly engageable with the opening of the body member.

In yet another embodiment, a dust cap for sealing engagement with an opening of a member is disclosed. The dust cap is removable from the opening of the member. The dust cap includes a body and an elastomeric portion. The body defines an outer perimeter and an aperture disposed along the outer surface. The elastomeric portion is located around the outer perimeter of the body and defines an outwardly extending projection. The outwardly extending projection is received by the aperture of the body and provides a grasping surface. The elastomeric portion sealingly engaged with the opening of the body member. The outwardly extending projection provides a surface that an operator may grasp. Thus, when the dust cap is removed from the opening, the outwardly extending projection serves as a pull-tab that the operator may grasp and pull upon.

DETAILED DESCRIPTION

The following detailed description will illustrate the general principles of the invention, examples of which are additionally illustrated in the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.

Referring now toFIG. 1, an accessory drive system10of, for example, an internal combustion engine of a vehicle is illustrated. The accessory drive system10includes an endless belt30that is used to drive a number of accessories, which are not illustrated inFIG. 1. Instead, the accessories are represented inFIG. 1diagrammatically by a number of pulley assemblies. Specifically,FIG. 1illustrates the belt30entrained around a crank pulley assembly12, a fan/water pump pulley assembly14, an alternator pulley assembly16, a power steering pulley assembly18, an idler pulley assembly20and a tensioner pulley assembly22.

The various accessories are driven through use of the pulley assemblies14,16,18,20and22that are themselves rotated by the belt30. For purposes of description, the alternator pulley assembly16will be focused on below. Although the alternator pulley assembly16is described below, those skilled in the art will appreciate that the disclosed dust cap (shown inFIG. 2as item56) may be utilized on any of the other pulley assemblies12,18,20as well. Moreover, it should also be noted that while the embodiments discussed herein disclose the dust cap as part of a pulley assembly for an accessory drive system, it is to be understood that the embodiments are merely exemplary in nature. Those skilled in the art will readily appreciate that the disclosed dust cap may be used in a variety of other applications as well, and may be used to provide sealing to any type of part. For example, in one embodiment the disclosed dust cap may be used in a non-rotatable part, such as a tensioner arm. A tensioner arm may oscillate back and forth, but does not rotate. Indeed, those skilled in the art will appreciate that the disclosed dust cap is not limited to use in rotatable or oscillatory components, and may be used in a static environment as well.

Referring now toFIGS. 2-3, the alternator pulley assembly16may be used to selectively transfer input torque from the belt30(shown inFIG. 1) to an input shaft32of an accessory (e.g., the alternator). In the exemplary embodiment as shown inFIGS. 2-3, the pulley assembly16includes a hub40that is engageable with the input shaft32, a spacer42, a roller bearing43, a needle bearing44, a thrust bearing45, a clutch actuator48, one or more biasing members50, a sleeve52, a retaining ring54, and a dust cap56, which are all housed within a bore60of a pulley body62. The hub40may define a bore58therethrough. The hub40may be mated to the input shaft32so as to prevent the hub40from freely rotating about the input shaft32. The hub40may be mated to the input shaft32using any known approach for allowing torque transmission between two rotational elements such as, for example, a Woodruff key (not illustrated).

The pulley body62surrounds the hub40, and the pulley bore60is sized such that the pulley body62may rotate about the hub40. The pulley body62is rotatable about an axis of rotation A-A. The pulley body62may also include an outer, peripheral belt-engaging surface70that engages the belt30(FIG. 1). The belt engaging surface70may be profiled including V-shaped ribs and grooves to mate with corresponding ribs and grooves (not illustrated) on the belt30. AlthoughFIG. 2illustrates V-shaped ribs located along the belt engaging surface70, other features such as cogs, flat or rounded ribs and grooves may be used as well to engage the belt30.

The sleeve52may include a bore80therethrough having a stepped configuration. Specifically, the bore80may include a first section82and a second section84, where the first section82has a larger diameter when compared to the second section84of the bore80. A step86may define the transition between the first section82and the second section84of the bore80. The first section82of the bore80may be sized to receive at least a portion of the biasing members50. In the non-limiting embodiment as shown inFIGS. 2-3, the biasing members50are illustrated as a plurality of Belleville washers. However, it is to be understood that any type of biasing member configured to exert a force in an axial direction may be used as well such as, for example, a wave or spiral compression spring.

The second section84of the bore80may be sized to receive a bushing68as well as the dust cap56. The bushing68may be press-fit into the second section84of the bore80. The dust cap56may be received within an opening88of the sleeve52. Specifically, the opening88of the sleeve52may be located along an outer surface89of the sleeve52(FIG. 3). As best seen inFIG. 4, which is an enlarged view of a portion of the sleeve52, the opening88of the sleeve52may define a lip90that extends inwardly, and towards the axis A-A of the hub40.

Referring back toFIGS. 2-3, the clutch actuator48may include a ramp construction or a roller-ramp construction that expands axially (i.e., has at least one component that is translatable along an axis of rotation A-A of the alternator pulley assembly16to a location further from another component thereof) as a result of rotational movement of at least a portion of the clutch actuator48. The axial expansion typically is a result of one component moving up or along an inclined feature or moving in response to the movement of a rolling element up or along an inclined feature.

The clutch actuator48in the embodiment ofFIGS. 2 and 3includes an upper ramp component94, a lower ramp component98, and one or more roller elements100enclosed therebetween. The roller elements100may be cylinders, balls, generally conical cylinders, or the like. The upper ramp component94is generally located adjacent to the biasing members50. The lower ramp component98may be located between the upper ramp component94and the thrust bearing45. Upper and lower are used herein as relative to positions of the components of the pulley assembly16as illustrated inFIG. 3with respect to the orientation of the page. The terms upper and lower are likewise applicable to the other drawings herein.

Referring toFIGS. 3 and 4, the dust cap56may be used to seal the opening88of the sleeve52, thereby substantially or completely preventing contaminants from entering the interior of the pulley body62. Thus, the dust cap56may be used to generally protect the components housed within the bore60of the pulley body62, such as the needle bearing44and the thrust bearing45, from contaminants. It should be noted that whileFIGS. 3 and 4illustrate the dust cap56sealing the opening88of the sleeve52, those skilled in the art will appreciate that the dust cap56may be sized to seal other openings of the pulley assembly16as well. For example, in another embodiment, the dust cap56may be used to seal an opening110of the pulley body62(shown inFIG. 3), where the dust cap56may be seated above the retaining ring54.

Referring toFIGS. 4-6, the dust cap56may include a body portion120and an elastomeric portion122. In the embodiment as shown inFIGS. 4-6, the body portion120may be constructed of plastic. However, in the alternative embodiments as shown inFIGS. 7-12which are described in greater detail below, the body portion120may be constructed of a metallic material. Referring back toFIGS. 4-6, the plastic of the body portion120of the dust cap56may be flexible enough such that installing and removing the dust cap56from the pulley assembly16does not substantially plastically deform the dust cap56. Some examples of plastics that possess the flexibility required include, but are not limited to, nylon 6/6 with a glass content of up to about thirty percent, nylon 6, nylon 4/6, or any plastic material where the melting point is greater than the elastomeric member molded over it.

Referring toFIG. 5, a portion of the elastomeric portion122has been removed in order to reveal an outer perimeter128of the body portion120of the dust cap56. In the exemplary embodiment as shown, the outer perimeter128of the dust cap56is substantially round or circular. Referring to bothFIGS. 5 and 6, the body portion120of the dust cap56may also include an inner surface130, and outer surface132, a lip134, an engagement feature136, and a stiffening button138.

Referring toFIGS. 4-6, the inner surface130of the dust cap56may face or be received by the opening88of the sleeve52, and the outer surface132of the dust cap56may be visible once the dust cap56is installed to the pulley assembly16. The lip134projects towards the inner surface130of the dust cap56, thereby creating an end surface140that may generally oppose an end surface142of the hub40. In one embodiment, the engagement feature136may be disposed at a central location along the outer surface132of the body portion120of the dust cap56. The engagement feature136defines an inwardly extending groove or recess144configured to receive a portion of a tool (not illustrated). The tool may be used by an operator to remove the dust cap56from the pulley assembly16. For example, referring specifically toFIG. 5, the recess144is shaped as a generally longitudinal slot that is configured to receive an end of a flat-head screwdriver (not illustrated). Although the recess144is illustrated in the figures as a longitudinal slot shaped to receive an end of a flat-head screwdriver, those skilled in the art will readily appreciate that the recess144may be shaped to receive a variety of tools. For example, in another embodiment, the recess144may be shaped to receive a Philips head screwdriver or a hex key.

Referring toFIGS. 4-6, once the dust cap56has been installed and seals the opening88of the sleeve52, an operator may subsequently remove the dust cap56from the opening using the engagement feature136. Specifically, in order to remove the dust cap56from the opening88of the sleeve52, an operator may insert the tool (e.g., a flat-head screwdriver) into the recess144of the dust cap56. The engagement feature136allows the dust cap56to be removed from the opening of the sleeve88without any substantial deformation or damage to either the body portion120or the elastomeric portion122of the dust cap56. Thus, the dust cap56may be manually installed to and subsequently removed from the opening88of the sleeve52multiple times. In other words, the engagement feature136enables the dust cap56to be reusable.

The stiffening button138is located opposite the recess144along the outer surface132of the body portion120of the dust cap56. The stiffening button138may provide stiffness and structural support to the recess144of the body portion120of the dust cap56. In one embodiment, the engagement feature136, or stiffening button138may be inserted within a die of a plastic injection molding machine (not illustrated) used to create the body portion120of the dust cap56. The insert may include the molding features needed to form the engagement feature136, or stiffening button138. The insert may be removed from the die, and replaced with another insert in order to customize the engagement feature136. For example, the insert that forms a longitudinal recess for receiving a flat-head screwdriver could be removed and replaced with an insert that forms a recess shaped to receive a hex key.

Continuing to refer toFIGS. 4-6, the elastomeric portion122of the dust cap56surrounds the outer perimeter128of the body, and is configured to sealingly engage with the opening88of the sleeve52. In one non-limiting embodiment, the elastomeric portion122of the dust cap56may be constructed of a melt processible thermoplastic elastomer (TPE). One commercially available example of TPE is sold under the commercial name SANTOPRENE™, and is available by the ExxonMobil Chemical Company of Houston, Tex.

The elastomeric material may be configured to elastically deform relatively easily when force is applied to the elastomeric portion122of the dust cap56, thereby allowing an operator to manually install the dust cap56within the opening88of the sleeve52. Specifically, during installation the elastomeric portion122of the dust cap56may elastically deform around the lip90of the opening88before the dust cap52is seated within the opening88. In particular, a sealing bead150located along an outer perimeter152of the elastomeric portion122may elastically deform to fit over the tip90located around the opening88of the sleeve52. The sealing bead150of the dust cap56is subsequently seated within the opening88of the sleeve52after installation. As seen inFIG. 4, the sealing bead150sealingly engages with the opening88of the sleeve52. The elastomeric portion122of the dust cap56may also include a lip154that is positioned adjacent the seating bead150. The tip154is configured to abut against and sealingly engage with the lip90located around the opening88of the sleeve52. Thus, both the sealing bead150and the lip154of the elastomeric portion122may substantially prevent contaminants from entering the opening88of the sleeve52.

AlthoughFIGS. 4-6illustrate the elastomeric portion122of the dust cap56including the sealing bead150and the lip154, those skilled in the art will appreciate that the elastomeric portion122may include any number of features and configurations for sealing. For example, in an alternative embodiment the elastomeric portion122of the dust cap56may include a double lipped configuration, where the elastomeric portion122may be used to seal between a static surface and a dynamic surface. Alternatively, the elastomeric portion122of the dust cap56may include a double lipped configuration to seal against two static surfaces concurrently.

Referring toFIGS. 5 and 6, in one embodiment the elastomeric portion122may be over-molded to the body portion120of the dust cap56. Over-molding is a process where a melt processible elastomer is molded directly onto a rigid component, such as the body portion120. Those skilled in the art will readily appreciate that if the elastomeric portion122is over-molded to the body portion120, then the body portion120of the plastic should include a melt temperature that is higher than the melt temperature of the elastomeric portion122such that the plastic material does not generally melt or thermally degrade during the over-molding process.

The body portion120and the elastomeric portion122may be bonded to another using a variety of different approaches. For example, in the embodiment as shown the elastomeric portion122is chemically bonded to body portion120of the dust cap56. Alternatively, or in addition to the chemical bond, the elastomeric portion122of the dust cap56may also be mechanically bonded to the body portion120by one or more gripping features (not illustrated) or anti-rotation features (not illustrated). Although an over-molding process is discussed, those skilled in the art will appreciate that other approaches may be used as well in order to attach the elastomeric portion122to the body portion120of the dust cap56. For example, in one embodiment the outer perimeter128of the body portion120of the dust cap56may include a groove (not shown) that receives a portion of the elastomeric portion122.

Turning now toFIGS. 7-9, an alternative embodiment of a dust cap256is illustrated. Similar to the embodiment as shown inFIGS. 2-6, the dust cap256may include a body portion220and an elastomeric portion222. The body portion220defines an outer perimeter228, an inner surface230, and outer surface232, a lip234, and an engagement feature236. The lip234projects towards the inner surface230of the dust cap256. As best seen inFIG. 8, the elastomeric portion222includes a recess240that is shaped to receive the lip234of the body portion220. Thus, the elastomeric portion222is bonded to the body portion220of the dust cap256using a mechanical bond.

In the embodiment as shown inFIGS. 7-9, the body portion220of the dust cap256may be constructed of a metallic material. In particular, the metallic material may be malleable enough such that the body portion220does not crack or otherwise break during a metal forming process employed to create the engagement feature236. Some examples of metallic materials that possess the required malleability include, but are not limited to, American Iron and Steel Institute (AISI) 1008 steel, AISI 1010 steel, and galvanized steel.

Similar to the embodiment as shown inFIGS. 2-6, the engagement feature236defines an inwardly extending groove or recess244configured to receive a portion of a tool (not illustrated). However, those skilled in the art will readily appreciate that the inwardly extending recess240typically includes a shorter height, or is shallower when compared to the recess144of the dust cap56shown inFIGS. 2-6due to limitations encountered during sheet metal forming. Moreover, as best seen inFIG. 9, the recess244may require an inside bend radius246that is about the same to as the thickness of the sheet metal that forms the body portion220of the dust cap256.

Referring toFIGS. 7 and 9, in some embodiments a special or customized tool (not illustrated) may be required by an operator to remove the dust cap256from the pulley assembly16(FIG. 2). A customized tool may be needed because the recess244may be too shallow to receive some types of conventional tools such as, for example, a flat-head screwdriver. As explained above, the recess244of the dust cap256may be too shallow to receive some types of conventional tools because of sheet metal forming limitations.

FIGS. 10-12illustrate yet another embodiment of a dust cap356. The dust cap356may include a body portion320and an elastomeric portion322. In one non-limiting embodiment, the body portion320may be constructed of a metallic material such as steel. The body portion320defines an outer perimeter328, an inner surface330, and outer surface332, a lip334, and a centrally located aperture338. The lip334projects towards the inner surface330of the body portion320dust cap356. As best seen inFIG. 11, the elastomeric portion322includes a recess340that is shaped to receive the lip334of the body portion320. Thus, the elastomeric portion322is bonded to the body portion320of the dust cap356using a mechanical bond.

The elastomeric portion322of the dust cap356defines an outwardly extending projection336, an inner surface350and an outer surface352. The outer surface352of the elastomeric portion322generally opposes the inner surface330of the body portion320. The outwardly extending projection336is disposed along the outer surface352of the elastomeric portion322, and is received by the aperture338located within the body portion320of the dust cap356. As best seen inFIGS. 11-12, the outwardly extending projection336may project from the dust cap356and provides a surface that an operator may grasp. Thus, when the dust cap356is removed from the pulley assembly16(FIG. 2), the outwardly extending projection336serves as a pull-tab that an operator may grasp and pull upon. Specifically, the operator may pull on the outwardly extending projection336in a direction away from the pulley assembly16(FIG. 2) to remove the dust cap356from the pulley assembly16without causing any substantial deformation to either the body portion320or the elastomeric portion322. Thus, the dust cap356is also reusable.

Referring generally toFIGS. 1-12, the disclosed dust caps may each be manually installed within the opening88of the sleeve52of the pulley assembly16without the need for any special tools (i.e., an operator may install the dust cap by hand). In the embodiments as shown inFIGS. 2-9, when the dust cap is subsequently removed from the opening88of the sleeve52, an operator may utilize a tool for removing the dust cap from the pulley assembly16. Thus, the dust caps may be removed without any substantial deformation or damage to either the body portion or the elastomeric portion. In other words, the disclosed dust caps are reusable. In the embodiment as shown inFIGS. 10-12, the disclosed dust cap may be removed from the pulley assembly16by pulling on the projection. Moreover, in addition to being reusable, the disclosed dust cap typically requires relatively low force (about 89 Newtons or 20 pounds) to be exerted by an operator during installation. Thus, the dust cap is generally not deformed or otherwise damaged during installation as well.

Finally, in the embodiments as shown inFIGS. 2-6the disclosed dust cap is constructed of plastic. The plastic dust caps may be installed to the pulley assembly16during shipment. Shipping the dust cap along with the pulley assembly may reduce cost and simplify subsequent connection of the pulley assembly16to a vehicle.

The embodiments of this invention shown in the drawings and described above are exemplary of numerous embodiments that may be made within the scope of the appended claims. It is contemplated that numerous other configurations of the dust cap may be created by taking advantage of the disclosed approach. In short, it is the applicant's intention that the scope of the patent issuing herefrom will be limited only by the scope of the appended claims.