Lock nut with adjustable retaining ring

A lock nut system includes a nut having a retaining member which includes a slot therein and a protrusion configured to fit within a recess of a shaft. A keeper includes a section receivable within the slot of the retaining member so when the nut is threadably engaged to the shaft to a desired torque the nut the keeper is slideable within the slot of the retaining member to allow the lock nut to be locked into position on the shaft without further rotation or other adjustment of the nut.

TECHNICAL FIELD

This invention relates, generally, to fasteners, and more particularly, to lock nuts for installing wheel hub and bearing assemblies on shafts such as axles or spindles, or for inhibiting rotation of shafts engaged with such nuts.

BACKGROUND ART

Lock nut systems are often connected to shafts and utilized to inhibit rotation of the retaining nut relative to such shafts. For example, such systems are often utilized on motor vehicles including axles and wheel ends. Typically, a lock nut will be engageable with a locking member or keeper which inhibits movement of the nut relative to the shaft. The locking member may include a protruding portion which extends into a slot or receiving portion of a shaft. The locking member may also engage the nut such that there is little or no movement between the nut and shaft. Such locking members are often made of stamped sheet metal.

In certain types of lock nuts the nut is locked into place on a shaft, such as an axle or spindle, by placing a retaining member into a recess within the nut. The retaining member or a keeper connected to the retaining member may have a plurality of teeth which interlock with teeth of the nut. Also, the retaining member or keeper may have a protrusion such as a key which interlocks with the shaft. To lock the nut on the shaft the protrusion or key must interlock with the shaft and the teeth of the retaining member or keeper interlocks with the teeth on the nut. However, if the nut is threaded onto the shaft at a specified torque, the nut may need to be rotated to adjust the position of the nut teeth so that they mesh with the teeth of the retaining member or keeper while the protrusion or key interlocks with the shaft. The adjustment of the nut by such rotation will, however, change the torque and resultant force applied by the nut onto the bearing on the shaft which the nut retains and contacts. Such a change in torque may not be desirable.

Thus, a need exists for lock nut systems which allow adjustment of the keeper relative to the retaining member to lock the nut into position without necessarily requiring additional rotation of the nut, and thus a change in the torque applied to the nut.

SUMMARY OF THE INVENTION

In accordance with the principles of the present invention, a lock nut system is provided which allows the lock nut to be mounted and tightened on a shaft to a specified torque and then locked into position without necessarily adjusting the position of the nut and thus changing the desired torque on the nut.

The lock nut system includes a nut having a plurality of nut teeth along an inner circumferential portion. The nut is threadably engageable with a shaft. The nut also includes a retaining member engageable with the nut. The system includes a keeper having a plurality of locking teeth configured to engage with the nut teeth. The keeper in engaged with the retaining member. When the nut is threadably engaged to the shaft with the retaining member engaged to the nut and the protrusion within the recess of the shaft, the keeper is slideable relative to the retaining member to allow the locking teeth to engage with the nut teeth to lock the nut into position on said shaft. The keeper is moveable relative to the retaining member in a clockwise and/or counterclockwise direction when the retaining member is engaged to the nut and the nut is engaged to the shaft. Thus, the retaining member, which may be shaped as a ring, is rotatable relative to the keeper when the keeper section slides relative to the retaining member.

In a preferred embodiment, the retaining member has a slot therein and a protrusion configured to fit within a recess of the shaft. The keeper has a section thereof receivable within the slot of the retaining member. The section of the keeper receivable within the slot of the retaining member generally extends in an axial direction relative to a central axis of the nut. The slot of the retaining member generally forms an opening in a direction normal to the axial direction when the retaining member is engaged to the nut. The keeper is moveable within the slot in a clockwise and/or counterclockwise direction relative to the central axis of the nut when the retaining member is engaged to the nut and the nut is engaged to the shaft. The protrusion may extend radially inward toward the central axis of the nut when the retaining member is engaged to the nut. The length of the slot of the retaining member allows the keeper to be moved relative to the slot to allow the locking teeth to move so they align and engage with the nut teeth without necessarily rotating the nut when the retaining member is engaged to the nut and the nut is engaged to the shaft.

In some embodiments, the nut may include at least one recess configured to receive the retaining member therein. The recess may be a circular recesses extending within an inside surface of the nut. The retaining member may extend continuously in an arc from within the recess and engaged with the nut. The nut may be a bearing retaining nut and/or optionally include a recessed surface adapted to face a surface of a bearing. The retaining member may have at least one leg configured to be received in said circular recess, including two legs elastically deformable toward one another to allow the retaining member to be engaged to the nut by inserting the two legs in said circular recess.

In another aspect, a method is provided. The method includes providing a nut having a plurality of nut teeth along an inner circumferential portion. The nut being threadably engageable with a shaft; and providing a retaining member engageable with the nut, the retaining member having a slot therein and a protrusion configured to fit within a recess of the shaft; configuring a keeper with a plurality of locking teeth to engage with the nut teeth and with a keeper section thereof receivable within the slot of the retaining member. When the nut is threadably engaged to the shaft with the retaining member engaged to the nut and the protrusion within the recess of the shaft, the section of the keeper is slideable within the slot and the keeper is slideable relative to the retaining member to allow the locking teeth to engage with said nut teeth to lock said nut into position on said shaft.

DETAILED DESCRIPTION

Lock nut systems may use retaining members and/or keepers to lock the nut on a shaft, as disclosed in U.S. Pat. Nos. 8,961,090 and 8,904,646, the specifications of which are incorporated herein by reference in their entireties. Such systems may be used to lock a nut onto a shaft at a specified torque setting where the specified torque setting of the nut is calculated to affect the wheel assembly and the bearings secured by the nut. Accordingly, when the nut is torqued to such specified setting, it is not desirable to further adjust, i.e. tighten or loosen the nut, as such movement will change the specified torque setting. In prior lock nut systems which do not utilize the principles of the inventive concepts herein, in order to properly lock the nut, the retaining member, which may include a protrusion, must align with a recess such as for example a slot in the shaft. In addition, the teeth on the keeper must align with the teeth on the axle nut so that the teeth mesh and the retaining member can be properly inserted and locked to the nut. Such proper alignment can only occur if the aforementioned teeth are aligned and the retaining member is also aligned with the recess of the axle. However, frequently such alignment does not occur when the nut is torqued to a specified setting. In such prior situations and systems, in order to align the teeth of the nut and retaining member while the protrusion is aligned with the slot of the nut, the nut must be either loosened or tightened so that the teeth of the nut align with the teeth of the keeper. Such further loosening or tightening may not be desired as it will change the nut's torque setting.

In accordance with the principles of the present invention, a lock nut system engageable with a shaft is provided. The nut may be locked onto the shaft without the aforementioned further loosening or tightening of the nut.

The lock nut system10and nut20, as shown inFIG. 1A, often function as a bearing retaining nut to secure a bearing assembly and wheel52on shaft46, typically an axle or a spindle.FIGS. 1B and 1Cdepict where the wheel and bearing assembly have been removed for simplicity. Referring toFIGS. 1A-1C, the nut20, in certain applications, may be desired to be tightened to a specified torque in order to impart such specified torque to a bearing and/or bearing assembly. For example, in certain applications, the lock nut is specified to be torqued to approximately 500 foot pounds so as to maintain such torque on the bearing of a bearing assembly along with a wheel on an axle or spindle. In certain embodiments, the lock nut may include a recessed surface facing the bearing. However, in other embodiments and applications, a recessed surface is not included in the nut.

In accordance with the principles of the present invention, in order to achieve alignment between the teeth of the nut and the teeth of the keeper without further rotation of the nut on the shaft, a retaining member40, as shown inFIGS. 4-9, includes a slot36as shown inFIG. 4to allow the keeper30to slide within the slot in a circumferential (clockwise and/or counterclockwise) direction so that the teeth of the keeper30align with the teeth of the nut120. As can be seen inFIGS. 3A and 3B, the keeper30may be slid within the slot to a first position as shown inFIG. 3A, and/or a second position as shown inFIG. 3B, and anywhere therebetween to allow the nut teeth120to interlock or mesh with the keeper teeth while the protrusion of the retaining member is aligned within the slot or recess of the shaft. In this situation, the nut need not be adjusted, by loosening or tightening in order to lock the retaining member and keeper into the lock nut so that the specified torque of the nut when applied to the shaft may be maintained.

In an exemplary embodiment, a lock nut system10includes a nut20, a keeper30and a retaining member40, as depicted inFIGS. 1A-1C. Lock nut system10may be useable on a shaft46. In particular, threads50of nut20may engage threads of the shaft46. Keeper30and retaining member40may engage nut20and keeper30may engage the shaft46to inhibit movement of the shaft relative to nut20.

Referring toFIGS. 1C and 1D, nut20may include a plurality of nut engaging teeth120extending circumferentially around an inner radial surface of nut20. For example, nut20may include60engaging teeth. As shown inFIG. 1DandFIG. 2, nut20may also include a shoulder24configured to receive keeper30. For example, shoulder24may extend circumferentially and face in the axial direction opposite the wheel bearing and assembly. The shoulder24may be spaced from an outer surface22of nut20in an axial direction relative to nut20such that keeper30is received between outer surface22and shoulder24. Shoulder24may also abut and support keeper30in an axial direction. Nut20may be molded or formed of powdered metal, for example. As described below, shoulder24of the nut20may include a slot60to receive the retaining member40.

Referring toFIG. 1DandFIG. 2, nut20may include a slot60extending circumferentially (e.g., completely or partially) around nut20. Slot60may be located between nut engaging teeth120and outer surface22of nut20. Also, slot60may have a radial depth sufficient to receive and retain retaining member40. Retaining member40may engage slot60. For example, a first leg42and a second leg43may be received in slot60. Further, a tab44of retaining member40(shown inFIGS. 4-9) may be received in slot60.

As shown inFIG. 6, keeper30may include a plurality of keeper teeth32configured to engage nut engaging teeth120of nut20such that movement between keeper30and nut20is inhibited when keeper teeth32and nut engaging teeth120are engaged to each other, such as when the retaining member40and keeper30are locked onto the nut as shown inFIG. 2. Referring toFIG. 2, andFIGS. 4-9, retaining member40may include a shaft engaging side having, for example, a protrusion33configured (e.g., shaped and dimensioned) to engage a shaft46by for example fitting within a recess such as, for example, a slot70on the shaft46to inhibit movement (e.g., rotational movement) of the shaft relative to keeper30. When threads50of nut20engage threads (not shown) of the shaft, keeper teeth32engage nut engaging teeth120, and keeper retaining member40engages slot60. For example, the engagement or meshing of keeper teeth32and nut engaging teeth120inhibits movement of keeper30relative to nut20and the engagement of engaging side33with the shaft inhibits movement between keeper30and the shaft thereby inhibiting movement between nut20and the shaft. Keeper30may include, for example, about fifteen keeper teeth32evenly spaced from one another, for example. Also, keeper teeth32on outer circumferential sides35of keeper30may have an axial height (i.e., relative to nut20) substantially equal to a distance from shoulder24to outer surface22. Keeper teeth32on an inner portion of keeper30may have a height substantially equal to a distance from shoulder24to slot60thereby allowing tab44of retaining member40to extend into slot60. More specifically, keeper teeth32on an inner portion have an axial height less than keeper teeth32on outer sides35. The reduced axial height on inner portion allow tab44to pass over teeth32to extend into slot60.

Referring toFIGS. 4 and 5, retaining member40may include a slot36configured (e.g., shaped and dimensioned) to receive a section38of the keeper30. For example, one or more bumps39(as shown inFIG. 4orFIG. 9) on the top of section38may be used to maintain the section38within the slot of the retaining member40and prevent the keeper30from moving axially from and separating from the retaining member. Other techniques and/or structures may be used to maintain the section within the slot of the retaining member, and to prevent the keeper from moving axially and/or separating from the retaining member. Section38is slideable within the slot in a first direction and position shown inFIG. 3Aand to a second direction and position shown inFIG. 3B, and in any position therebetween. In unillustrated examples, slot38along with keeper30could be larger such that more of retaining member40is received therein. In a further unillustrated embodiment, keeper30could extend partially or entirely circumferentially around nut20(e.g., abutting shoulder24) and could include keeper teeth32around an entire outer circumference of keeper30, which therefore could engage some or all of engaging teeth120.

Retaining member40may be elastically deformable to allow it to be received in slot60. For example, first leg42and second leg43may be deformed (e.g., in a direction substantially perpendicular to the axis of nut20) toward one another prior to being inserted axially past outer surface22of nut20to allow retaining member40, and keeper30to be attached thereto. First leg42and second leg43may then be elastically returned toward slot60. For example, retaining member40may be formed of ASTM A228 spring steel as will be understood by those skilled in the art. Also, retaining member40may be cylindrical or otherwise arcuately shaped. Alternatively, retaining member40could be formed of other materials and/or formed in other shapes to allow retaining member40to receive in slot60and/or cavities (e.g. cavity36and cavity38) of keeper30.

As shown inFIG. 2, keeper30functions to engage with the teeth120of the lock nut20so as to allow the retaining member40to fit into slot60of the nut and lock the nut20into position on the shaft46. Further, keeper30may be formed or molded of powdered metal, for example. Also, keeper30could be formed in different shapes to allow it to engage a shaft to thereby inhibit movement of such shaft. For example, shafts may have different shaped recesses and the keeper30should be shaped so that its protrusion33, for example, fits within the recess to prevent relative rotation therebetween.

Retaining member40when received in slot60may align keeper30such that keeper teeth32are engaged with the nut teeth120. Further, retaining member40when received in slot60provides resistance in an axial direction relative to nut20thereby inhibiting movement of keeper30axially away from shoulder24toward outer surface22. Also, the one or more bumps39of keeper30may be formed such that retaining member40received in slot60remains engaged or connected to keeper30while allowing the keeper to move within slot36of the remaining member.

In accordance with the principles of the present invention, the axle nut20is installable on the shaft46using the following process. Lock nut20, without the retaining member40or keeper engaged thereto, is threadably mounted onto a shaft46. The shaft will typically contain a wheel and bearing assembly thereon. If the lock nut is to be tightened to a desired torque, which may be specified by wheel end manufacturers or suppliers, the nut20is tightened to such torque. Typically, the range of torques specified for truck wheel ends ranges between 350 and 500 foot pounds. For different wheel end assemblies, manufacturers and suppliers may specify different lock nut installation and bearing setting procedures. Such procedures should be typically followed using the lock nut disclosed herein. Once such procedures are completed and the lock nut is tightened to a specified torque, the retaining member may be installed and assembled to be engaged into the lock nut.

As depicted in the figures herein, the legs42,43of the lock nut may include openings for the use of retaining ring pliers to contract the radius or circumference of the ring. However, alternatively the legs may include tabs which allow the radius of the retaining member to be compressed by hand without the use of tools. The retaining member may be inserted into the slot60of the nut20with the protrusion33inserted into the recess70of the axle. With the protrusion33inserted into the axle recess70and the retaining member40placed into the lock nut20slot60, the teeth32on the keeper may or may not align with the teeth120of the nut20such that the teeth32and120interlock or mesh with one another (as shown inFIG. 2).

If the teeth align properly and mesh with one another, the alignment of such teeth of the keeper32with the nut teeth120and the insertion of the retaining member40into the slot60of the nut will place the lock nut in the lock and assembled position, without rotation of the nut and disruption of the torque previously applied to the nut. However, if the teeth32of the keeper do not align with the teeth120of the nut such that the teeth do not mesh with one another, the keeper30may be moved within slot36of the retaining member. The keeper30may be moved, for example, to the position shown inFIG. 3Aor, for example, the position shown inFIG. 3B, or any position therebetween such that the teeth of the keeper32align and mesh with the teeth of the nut120. With this procedure, the nut need not be loosened or tightened in order to align the teeth of the keeper32with the teeth of the teeth120of the nut20. Accordingly, with this procedure the nut need not be further adjusted to be locked into place on the shaft so there is no adjustment or change in the torque applied by the nut onto the wheel end and/or bearing assembly.

Use of molded metals (e.g., powdered metal) as described above for the nuts and keepers allows a finer spacing of teeth than other materials (e.g., sheet metal keepers) and methods thereby allowing finer adjustment of nuts, keepers, and shafts relative to each other, while preventing or inhibiting movement of the keeper relative to the nuts. For example, the use of powdered metal instead of stamped sheet metal for a keeper allows a higher number of keeper teeth to be provided per unit area thereby allowing more engagement with corresponding engagement teeth on the nut. The ability of the molded teeth in the present invention to resist torque is significantly higher than that afforded by a stamped part of previous inventions because of the ability to economically mold teeth with greater axial dimensions as well as the ability to include a greater number of engaging teeth per unit area, when using powdered metal instead of stamped sheet metal. A finer adjustment may be therefore be provided of the keeper relative to the nut due to such increased number of keeper teeth and corresponding increased number of engaging teeth of a nut per unit area. For example, a finer adjustment of bearing clearance can be achieved with the use of the finer pitch of the molded teeth. Further, the use of molded metals (e.g., powdered metals) for keeper30allows it to engage a shaft without being significantly deformed or significantly deforming the shaft in contrast to other materials used for this purpose (e.g., stamped sheet metal) which may deform after a period in use or cause deformation (e.g., stripped threads) of a shaft to which it is engaged. Additionally, such a molded keeper may be harder and stronger than a stamped sheet metal keeper thereby inhibiting such damage. Thus, a higher torque loading may be provided utilizing molded metals (e.g., powdered metal) relative to other materials (e.g., a sheet metal stamped keeper) to form keepers and nuts and without resulting in failure, i.e., a risk of damage to the shaft or axle due to over torque is minimized. Also, keepers may resist deformation when engaged with a slot of a shaft for the same reasons.

Although the above-described lock nuts and keepers are described as being molded or formed of powdered metal, these nuts and keepers could be die cast, molded of other materials, or formed in any other manner which would allow the teeth of the keeper and nut to inhibit movement relative to each other along with the keeper and shaft inhibiting movement relative to one another. Also, the retaining member could be formed of sheet metals or the same materials as the keepers and/or nuts. Such retaining members could also be formed of plastic or any other material which would axially hold a keeper (e.g., keeper30) such that the keeper teeth thereof (e.g., keeper teeth32) are engaged with nut engaging teeth (e.g., engaging teeth120) of a nut (e.g., nut20). For example, such retaining members could be formed of plastics which satisfy this criteria.