Dust boot with grease relief

A dust boot for a suspension assembly, particularly a ball joint, includes a side wall with at least one relief opening and a cover that overlies the at least one relief opening.

FIELD OF INVENTION

The invention relates to a dust boot for parts used in suspension systems. More particularly, the invention relates to dust boots used in connection with suspension parts of vehicles having retained grease. Most particularly, the invention relates to dust boots used in connection with grease retaining ball joints.

BACKGROUND

Suspension parts, such as ball joints, are frequently pre-lubricated, moving assemblies enclosed in a casing to prevent dirt and debris from entering the assembly. Any dirt or debris that enters the assembly may erode the contacting surfaces and prevent the assembly from moving or functioning properly.

By way of an exemplary suspension part, a ball joint, whether self-lubricating or manually lubricated, may build up lubricant pressure on the boot due to active movement of the assembly. If this pressure is not relieved, it can limit the flexibility of the boot and lead to a failure of the boot. This boot failure may lead to premature failure of the entire suspension assembly due to the ingress of dirt or debris. It has been known to relieve this pressure through a vent in the boot. However, the effectiveness of this approach can depend on the flexibility of the boot and the release of lubricant through the vent may attract and hold dirt or debris that could enter the assembly.

In view of the above, it has been determined that the boot vent should be protected from the external environment.

SUMMARY

A dust boot is provided with a side wall that has a covered relief opening. The cover overlying the relief opening extends outwardly so that the relief opening is recessed inwardly from the forward face of the cover.

The dust boot is particularly suitable for use with a ball joint that is pre-lubricated.

DETAILED DESCRIPTION

With reference toFIG. 1, the boot100is used in conjunction with vehicle suspension parts, such as a ball joint, to serve a number of purposes and is commonly referred to as a dust boot. The boot100comprises a body200with a first open surface210, a second open surface220, and a side wall230that extends between the first open surface210and the second open surface220to define an interior space that encloses a suspension element. The side wall230of the body200curves from the first surface210to the second surface220. The side wall230of the boot100includes at least one relief or vent opening260. The side wall230includes at least one cover270that overlies the opening260. The side wall230preferably includes protrusions235. The protrusions235are areas of thickened material that stabilize the side wall230and balance the stresses with the cover270.

As shown inFIG. 1, the cover270forms a structure, similar to a dormer window on a house roof, with a top265and sides275that extend outwardly from the side wall230to define a forward face280. The opening260is preferably a generally horizontal slot that is recessed inwardly from the forward face280.

The body200is typically molded of a flexible material, like rubber or polyurethane, so it can respond to movement of the enclosed suspension parts. In many applications, such as ball joints, the body200may be compressed or flexed and the lubricant within is placed under pressure. This pressure places stress on the side wall230. With the present invention, the slot260flexes and opens to relieve the pressure. Because the slot260is recessed and has the cover270, it has protection from external debris that may enter the slot260if it was not protected.

As shown inFIG. 2, the first surface210defines an opening240that extends through the second surface220. The diameter of the opening240and the side wall230increases from the first surface210to the second surface220, thereby creating the dome shaped body200. As shown inFIG. 2, the reinforcement protrusions235are preferably spaced at equal distance around the circumference of the dome shaped body200.

As illustrated inFIGS. 3 and 4, the boot100is useful in conjunction with a ball joint assembly300. The ball joint300includes the boot100, the base400, and the bearing stud500. The second surface220of the boot100fits on a lip at the open end of the socket assembly400. The bearing stud500has a ball end510and an elongated shaft520that extends through the boot100and out of the first surface210to provide the connecting threads530. The side wall230includes upper recess288and lower recess290which are configured to hold an upper compression ring285and a lower compression ring295respectively that secure the boot100to the assembly300.

As shown inFIG. 4, the base400has a polymer bearing410in the bowl shaped housing420on which ball510moves. The base400is typically lubricated in the bowl shaped housing420and in the lubricant receiving area245. Normal operation of the ball joint assembly can cause movement of the lubrication and a pressure build up in the lubricant receiving area245. In some applications, the end of the elongated shaft520has a recess535that is configured for an Allen or hex wrench or a ratchet pin.

As shown in enlargedFIG. 5, the boot100has a relief opening260in the side wall230. The boot100has a typical cross section throughout except in the area of the cover270. The side wall230has an internal recess233that communicates with the relief opening260. The side wall230has a reduced thickness in the area263surrounding relief opening260to further facilitate the opening and flexing of the relief opening260.

These structural features help to direct excess pressure toward the relief opening260which flexes and opens. In those cases where lubricant is pushed out the relief opening260, it possible for lubricant to stick to the side wall230and attract debris that could enter the relief opening260when it opens again.

The cover270serves as a protective covering for the relief opening260and reduces exposure of the relief opening260to dirt, dust, and debris in the surrounding environment. As shown inFIG. 5, the area of the relief opening260is recessed inwardly from the forward face280of the cover270. The top265and sides275of the cover270create a hood over the recessed relief opening260that prevents external debris from entering the boot through the open relief opening260.