PURGING DUST BOOT

This application claims the benefit of U.S. application Ser. No. 16/392,027 which was filed on Filed Apr. 23, 2019 and is incorporated by reference as if fully set forth.

The present invention relates generally to a cover for a suspension assembly that is often referred to as a dust boot. Such dust boots are commonly used with steering components like ball joint assemblies. The dust boot of the invention relates most particularly to pressure generated by lubrication that is subject to movement of the lubrication as a result of active movement of the assembly.

Movable joints are commonly used in vehicle suspension systems. Such applications typically require the use of a boot to protect the joint from dirt, debris and other contaminants that may cause the joint surfaces to erode. Many movable joint assemblies include a lubricant that surrounds the joint and is contained by the boot. The movement of the joint and flexing of the boot can cause internal pressure on the lubricant. To relieve that pressure, the boot may have a small opening to relieve pressure during active movement of the assembly. However, such an opening can allow contaminants to enter the assembly and degrade its operation or cause pre-mature failure. Accordingly, it is desirable to have a boot that allows pressure relief and limits the ingress of contaminants.

A suspension assembly boot that protects a moveable joint and contains a lubricant associated with the joint is disclosed. The dust boot of the present application includes at least one venting aperture that is surrounded and protected by a structure that limits the ingress of foreign matter into the boot as a result of the venting aperture.

With reference to FIG. 1, the boot 10 has a body portion 20 that is generally dome shaped and defines an interior lubrication cavity, see 22 in FIG. 4. The body portion 20 has circular upper end 24 that has an opening 26 and a recess 28 that joins with the top of the body portion 20. The body portion 20 has a circular lower end 30 and a recess 32 that joins with the bottom of the body portion 20.

The boot 10 is molded of a flexible material, such as rubber or polyurethane, and includes at least one pressure relief slot 40 that extends through dome wall 42 and into lubrication cavity. The external termination of the pressure relief slot 40 is coplanar with the exterior of dome wall 42. A generally rectangular protective barrier 50 raises up from the exterior of the dome wall 42 and surrounds the pressure relief slot 40. The protective barrier 50 has an outer face that generally follows the contour of the dome wall 42, see FIGS. 3 and 4. The protective portion of protective barrier 50 is largely established by the side walls 53A through 53D. The sidewalls 53A through 53D are spaced from the pressure relief slot 40 and create a recessed flat surface area 56 that is around the pressure relief slot 40 and within the sidewalls 53A through 53D. The lower legs 54 and 55 extend from the protective barrier 50 and provide additional stress relief and force distribution for the protective barrier and the dust boot 10.

As illustrated in FIG. 2, the boot 10 may include a second protective barrier 50. In addition, the preferred embodiment includes at least one projection 60 on the body portion 20. As depicted in FIG. 2, the boot 10 has two protective barriers 50 and two projections 60. The barriers and 50 and projections 60 may be alternated or grouped according to the application. In addition, a single barrier 50 and a single projection 60, preferably, are positioned opposite to each other. It is preferred that the selected number of barriers and projections be positioned so that they are equidistant from each other around the dome wall 42.

With reference to FIGS. 4 and 5, the structures for the protective barrier 50 and the projection 60 will be explained in more detail. The body portion 20 generally has a uniform thickness throughout with the exception of the protective barrier 50 and the projection 60. The projection 60 has increased material that forms the projection outwardly from the exterior of the dome wall 42. The interior of the dome wall 42 beneath the projection 60 remains constant with the overall interior.

With reference to FIG. 5, the protective barrier 50 has increased material in the sidewalls 53A through 53D and reduced material in the recessed flat surface area 56 that includes slot 40. An interior recess 57 is formed in the interior wall of the body portion 20 to create a flow path toward the slot 40. The reduced material in surface area 56 results in more flexible and easier access to the slot 40.

Through the combination of varied material thickness and spacing of the protective barrier or barrier 50 and the projection or projections 60, the boot 10 retains sufficient strength while having the desired flexibility. The combination of protective barriers and projections also help to distribute stress and contribute to boot life.

FIG. 4 illustrates a ball joint assembly with a dust boot according to the invention. The dust boot 10 is fitted to the ball joint assembly 70 in the usual manner and retained by securing rings 72 and 74 in the grooves 28 and 32.