Lubricant cartridge for wheel end assemblies

Abstract

A wheel end assembly of a heavy-duty vehicle includes a pair of bearings mounted on an axle spindle, and a wheel hub rotatably mounted on the bearings so that the bearings, the axle spindle, and the wheel hub generally define a cavity in the wheel end assembly. The wheel hub is formed with a port that communicates with the cavity and atmosphere. A lubricant cartridge includes a generally rigid body defining a chamber for containing a predetermined amount of semi-fluid grease. The cartridge also includes a generally rigid nozzle that is connected to the body and is in fluid communication with the chamber. The nozzle defines an opening and is formed with features for removably connecting the cartridge to the wheel hub port. Semi-fluid grease is urged from the cartridge chamber through the nozzle, through the port, and into the cavity to lubricate the wheel end assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60 / 833,685, which was filed on Jul. 27, 2006.BACKGROUND OF THE INVENTION[0002]1. Technical Field[0003]The invention relates to the lubrication of vehicle wheel end assemblies, and in particular to the lubrication of wheel end assemblies of heavy-duty vehicles, such as tractor-trailers. More particularly, the invention is directed to a cartridge containing a predetermined amount of semi-fluid grease for lubricating a wheel end assembly of a heavy-duty vehicle, in which the cartridge includes a nozzle adapted for securely connecting to a lubricant port formed in a wheel hub of the wheel end assembly.[0004]2. Background Art[0005]For many years, the heavy-duty vehicle industry has utilized wheel end assemblies which typically are mounted on each end of one or more axles. Each wheel end assembly typically includes a hub rotatably mounted on a bearing assembly, w...

AI Technical Summary

Benefits of technology

The present invention provides a lubricant cartridge for delivering semi-fluid grease to a wheel end assembly of a heavy-duty vehicle. The cartridge is easy to handle, efficiently dispenses the grease, and securely connects to a fill port in the wheel hub to minimize or eliminate spillage or loss of lubricant during the fill operation. The technical effects of the invention include improved lubrication of the wheel end assembly, reduced maintenance costs, and improved operational efficiency.

Problems solved by technology

Therefore, the wheel end assembly must be sealed to prevent leakage of the lubricant, and also to prevent contaminants from entering the assembly, both of which could be detrimental to its performance.

Historically, oil has been used as the lubricant for the bearing assemblies, but it may not be the optimum lubricant for achieving the goal of increased bearing assembly life.

More particularly, if the main seal on the wheel end assembly degrades, there is a tendency for the oil to leak out of the assembly due to its relatively low viscosity in comparison to other lubricants.

When the oil leaks out, the bearing assembly may become under-lubricated, which reduces its life.

Moreover, when the oil leaks out of the wheel end assembly, it may leak onto components of an associated brake system, such as the brake shoes, which must then be repaired, thereby increasing the cost associated with an oil leak.

Such potential disadvantages associated with oil leaks have led to increasing use of semi-fluid grease as an alternative to oil as a lubricant for bearing assemblies in wheel end assemblies on non-drive axles.

However, semi-fluid grease does not readily flow to both the inboard and outboard bearings and the hub area proximate the bearings using such a hubcap fill hole.

In any method of filling the wheel end assembly with semi-fluid grease, metering of the grease to inject the proper amount is an important consideration, since the addition of too much lubricant may create excessive pressure within the wheel end assembly and cause the main seal to leak, while the addition of too little lubricant may lead to inadequate lubrication of the bearing assembly and thus reduce its life.

This prior art method includes a distinct disadvantage, since the lack of the installation of the outboard bearing during grease introduction requires that an operator maintain a relatively horizontal position of the wheel hub to prevent damaging the main seal of the wheel end assembly.

That is, without the outboard bearing in place, there is a tendency for the outboard end of the wheel hub to drop down onto the axle spindle, which in turn can kink or damage the main seal at the inboard end of the wheel hub.

In addition, while this prior art method may be employed somewhat efficiently during initial assembly of the wheel end assembly with factory-trained assemblers, it is much less practical for use in the field, such as during servicing of the wheel end assembly in a repair / maintenance facility, since the wheel end assembly would have to be at least partially disassembled just to add lubricant.

In the prior art, radially-oriented ports were drilled and tapped through the wall of the wheel hub between the inboard and outboard bearings, but such radially-oriented ports included certain disadvantages, such as increased manufacturing costs and an inability to be used on thin-walled wheel hubs.

This procedure requires significant time and effort, and as a result, may not be adequately performed in some cases.

That is, the person servicing the assembly may not accurately measure the amount of grease to be added.

Such inaccuracy could lead to the addition of too much or too little grease, which are both undesirable, as described above.

However, the flexible bag exhibits certain disadvantages.

More particularly, since the bag is flexible, it may easily slip from a user's hands during the filling operation, the chances of which are increased in the field, since the user's hands may be dirty and thus slippery from working with components that have gathered dirt and grime from over-the-road travel.

In addition, since the bag is flexible, the bag itself must be squeezed to introduce the semi-fluid grease into the wheel end assembly, and the user may not be able to squeeze substantially all of the premeasured semi-fluid grease out of the bag.

Moreover, the flexible tube that is inserted into the wheel hub fill port does not provide a secure connection to the wheel hub and / or may slip out of the fill port during the filling operation, in either case possibly resulting in spillage or loss of grease intended for introduction into the wheel end assembly.

The above-described disadvantages of prior art delivery systems for filling wheel end assemblies of heavy-duty vehicles with semi-fluid grease in the field, and at times during initial assembly, have created a need in the art for a lubricant cartridge containing a predetermined amount of semi-fluid grease, which is easy to handle and efficiently dispenses the grease, and which provides a secure connection to a fill port formed in a hub of the wheel end assembly to minimize or eliminate loss of grease intended for lubrication of the assembly.

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