Vehicle hub having reduced lubricant cavity

A vehicle hub includes a generally cylindrical axially extending body forming an inboard bearing seat, an outboard bearing seat and lubricant cavity therebetween. The hub is preferably cast as an integral component from a ductile iron. A plurality of integral open ribs connects the body to a radially extending flange. The ribs form an open area between the body and the ribs. The open structure of ribs providing increased cooling for the bearings and lubricant while decreasing weight without sacrificing hub strength and rigidity. The lubricant cavity is of a reduced diameter which reduces the volume of lubricating medium required to fill the cavity and minimizes the centrifuge effect acting upon the medium. The beneficial effects of the improved hub providing increased bearing cooling, lighter weight, a smaller lubricant cavity and increased strength.

BACKGROUND OF THE INVENTION
 The present invention relates to a vehicle hub, and more particularly to a
 vehicle hub having improved life and bearing cooling.
 Typical vehicle hubs include mounting seats for inboard and outboard
 bearings. The bearings are fitted into the hub and allow the hub to rotate
 on the end of a relatively stationary axle assembly. To allow the hubs to
 rotate freely and to reduce heat caused by friction, the bearings must be
 lubricated. A lubricant chamber is therefore located in the hub
 intermediate the bearing seats to retain a lubricating medium such as
 grease. The hubs commonly provide rather large capacity lubricating
 chambers to retain a large volume of lubricating medium to provide long
 lasting performance.
 As the lubricant chamber is increased, however, a larger quantity of
 lubricant is required to completely fill the lubricating cavity. Further,
 as the lubricant cavity is increased in diameter, the lubricating medium
 undergoes greater centrifugal force as the hub rotates about the axle. The
 lubricating medium is thrown away from the bearings, thus making proper
 lubrication more difficult. The reduced lubrication increases the effects
 of friction and heat possibly leading to a bearing failure. This
 centrifuge effect is a particular problem with viscous lubricating mediums
 such as synthetic grease.
 Accordingly, it is desirable to provide an improved vehicle hub having
 improved bearing cooling and improved compatibility with synthetic grease.
 SUMMARY OF THE INVENTION
 The improved vehicle hub according to the present invention includes a
 generally cylindrical axially extending body having a centrally located
 opening formed therethrough. The body forms an inboard bearing seat, an
 outboard bearing seat and lubricant cavity therebetween. The hub further
 provides a plurality of integral open ribs which connect the body to a
 radially extending flange.
 The ribs are formed such that an open area is formed between the body and
 the ribs. The open structure of the ribs provides increased cooling to the
 body. The bearing seats and therefore the bearings receive additional
 cooling through the open rib structure. Further, the open ribs provide the
 added benefit of decreasing the overall hub weight without sacrificing hub
 strength and rigidity.
 The hub lubricant cavity is preferably of a reduced diameter that is less
 than the inboard and outboard bearing seat diameter. By decreasing the
 size of the lubricant cavity, the volume of lubricating medium required to
 fill the cavity is proportional decreased. Less lubricating medium is
 necessary to provide long lasting performance. Further, the reduced
 diameter of the lubricant cavity minimizes the centrifuge effect acting
 upon the medium. The bearings receive a more constant supply of
 lubricating medium which further increases the performance and longevity
 of the bearings.
 The hub is preferably cast as an integral component from a ductile iron.
 Ductile iron facilitates a lightweight hub design while increasing heat
 transfer properties from similar iron hubs. Thus, additional heat is
 carried away from the bearings and lubricant. The beneficial effects of
 the improved hub according to the present invention include increased
 bearing cooling, lighter weight, a smaller lubricant cavity and increased
 strength.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 FIG. 1 illustrates a vehicle hub 10 according to the present invention. The
 hub 10 includes a generally cylindrical axially extending body 12 defining
 a central axis of rotation X. A centrally located opening 14 formed
 therethrough receives an axle spindle (shown generally at 16.) The body 12
 forms an inboard bearing seat 18, an outboard bearing seat 20 and
 lubricant cavity 22 therebetween. The inboard bearing seat 18 and the
 outboard bearing seat 20 respectively receive bearing assemblies 19 and
 21. The body 12 further provides a plurality of integral open ribs 24
 which connect the body 12 to a radially extending flange 26. Preferably,
 the body 12, ribs 24 and flange 26 are an integral one-piece cast metal.
 Referring now to the side view of FIG. 2, the open structure of the hub 10
 is shown. The hub 10 is strengthened by a plurality of the integral open
 ribs 24 which are attached between the radially extending flange 26 and
 the body 12. As shown, the ribs 24 extend from an inboard portion 32 of
 the body 12 and attach to the flange 26. The ribs 24 are formed such that
 an open area 34 is formed between the body 12 and the ribs 24. The open
 areas around ribs 24 provides increased cooling for the body 12. As shown
 in FIG. 3, the radially extending flange 26 projects from the body 12 and
 includes a plurality of mounting apertures 28 for receipt of fasteners
 (not shown) to mount the hub 10 to a wheel rim (not shown). The hub 10
 also includes a plurality of apertures 30 formed in the body 12. The
 apertures 30 are adapted to receive fasteners (not shown) to secure a hub
 cap (not shown).
 The open structure of the hub 10 is clearly shown in the sectional view of
 FIG. 4. Open area 34 is defined between the body 12 and the ribs 24. The
 ribs 24 define a bridge over the open area 34 to provide a direct cooling
 path to the body 12. The top part of FIG. 4 illustrates an area
 intermediate the ribs 24. It is to be understood that although six ribs 24
 are shown in the disclosed embodiment any number and relationship is
 likewise contemplated by the present invention.
 As the ribs 24 are open or spaced from body 12 structure, a greater area of
 the body 12 is exposed. The inboard bearing seat 18, outboard bearing seat
 20 and the lubricant cavity 22 receive increased cooling than if the ribs
 24 were solid. Further, the open ribs 24 provide the added benefit of
 decreasing the overall hub weight without sacrificing hub strength and
 rigidity.
 The open ribs 24 preferably span the axial length of lubricant cavity 22.
 The body 12 provides the greatest exposed area to the environment.
 Preferably, the lubricant cavity 22 is of a diameter less than the inboard
 18 and outboard 20 bearing seat diameter. By decreasing the size of the
 lubricant cavity 22, the volume of lubricating medium required to fill the
 cavity is proportional decreased. Less lubricating medium is thus
 necessary to provide long lasting performance. Further, the reduced
 diameter of the lubricant cavity 22 minimizes the centrifuge effect acting
 upon the medium. The bearings receiving a more constant supply of
 lubricating medium which further increases bearing performance and
 longevity. This is particularly advantageous for use with synthetic grease
 which typically have a higher viscosity and are more susceptible to heat.
 The hub 10 is preferably cast as an integral component from a ductile iron.
 Ductile iron further decreases the hub weight while increasing heat
 transfer properties. Thus, additional heat is carried away from the
 bearings and lubricant without increasing weight. These beneficial effects
 provide an improved hub 10 having increased bearing cooling, lighter
 weight, a smaller lubricant cavity and increased strength.
 The foregoing description is exemplary rather than defined by the
 limitations within. Many modifications and variations of the present
 invention are possible in light of the above teachings. The preferred
 embodiments of this invention have been disclosed, however, one of
 ordinary skill in the art would recognize that certain modifications would
 come within the scope of this invention. It is, therefore, to be
 understood that within the scope of the appended claims, the invention may
 be practiced otherwise than as specifically described. For that reason the
 following claims should be studied to determine the true scope and content
 of this invention.