Seal assembly

An apparatus is configured for sealing a hole in a panel having a first surface on one side of the panel and a second surface on the other side of the panel. The apparatus includes a boot and a seal member. The boot includes a first portion having a first bellows, a second portion having a second bellows, and a third portion that interconnects the first portion and the second portion. The seal member is operatively connected to the third portion of the boot and is configured such that, when the third portion of the boot is within the hole, the seal member contacts the panel to form at least one seal around the hole.

TECHNICAL FIELD

This invention relates to seals that seal holes in panels having shafts extending therethrough.

BACKGROUND

A motor vehicle typically includes a dash panel, or bulkhead, that separates the passenger compartment from an engine compartment. A steering shaft passes through a hole in the dash panel to connect the steering wheel, which is in the passenger compartment, to the steering gear, which is in the engine compartment. A seal is typically employed between the dash panel and the shaft to prevent noise, gases, water, and debris from entering the passenger compartment from the engine compartment via the hole in the dash panel.

SUMMARY

An apparatus is provided for sealing a hole in a panel having a first surface on one side of the panel and a second surface on the other side of the panel. The apparatus includes a boot and a seal member. The boot includes a first portion having a first bellows, a second portion having a second bellows, and a third portion that interconnects the first portion and the second portion. The seal member is operatively connected to the third portion of the boot and is configured such that, when the third portion of the boot is within the hole, the seal member contacts the panel to form at least one seal around the hole.

The seal member provides a seal around the hole, while the boot provides a seal around a shaft that extends through the hole. Installation of the shaft through the boot may require repositioning part of the boot relative to the panel. The apparatus provided herein facilitates the installation of the shaft because the bellows decouple the seal member from loads generated by movement of the boot during shaft installation, thereby maintaining the position of the seal member relative to the panel and thus increasing the efficacy of the seal member.

DETAILED DESCRIPTION

Referring toFIG. 1, a panel10has a first surface14on a first side18and a second surface22on a second side26. The panel10defines a circular hole30that extends through the panel10from the first surface14to the second surface22. In the embodiment depicted, the panel10is part of a motor vehicle34, and separates an engine compartment (on the first side18) and a passenger compartment (on the second side26). The hole30is to accommodate a steering shaft (shown at38inFIG. 2) extending from the engine compartment to the passenger compartment. A seal apparatus42is configured to seal the hole30and thereby prevent or limit the transmission of noise, debris, and water through the hole30, while allowing the steering shaft38to pass therethrough.

The seal apparatus42includes a boot46having a first portion50, a second portion54, and a third portion58. The first portion50includes a first bellows62. The second portion54includes a second bellows66. The third portion58extends through the hole30and interconnects the first portion50and the second portion54.

The seal apparatus42also includes a seal member70, which is operatively connected to the third portion58of the boot46. The seal member70is configured such that, when the third portion58of the boot46is disposed within the hole30, the seal member70contacts the panel10to form at least one seal74around the hole30.

The boot46is generally cylindrical, although other shapes may be employed within the scope of the claimed invention. For example, the boot46may be conical or frusto-conical. The boot46is shown inFIG. 1in an unstressed state. In the unstressed state, the bellows62,66are axisymmetric, i.e., symmetric about axis A1.

The boot46defines a chamber78. The first portion50of the boot46defines a first opening82of the chamber78on the first side18of the panel10. The boot46includes a bearing86that is operatively connected to the second portion54of the boot46. The bearing86defines a second opening90of the chamber78on the second side26of the panel10. More specifically, in the embodiment depicted, the bearing86includes a plastic support member88defining a hole or cylindrical aperture89. A low-friction O-ring or bushing93is mounted to the plastic support member88inside a groove around the aperture89and defines the second opening90.

The steering shaft is extendable through the first and second openings82,90and the chamber78, as shown inFIG. 2.FIG. 2depicts the seal apparatus42with the steering shaft38extending through the first and second openings82,90. Referring toFIG. 2, wherein like reference numbers refer to like components fromFIG. 1, the vehicle34includes a steering gear assembly94that is operatively connected to the steering shaft38and that includes a housing98.

To engage the steering shaft38with the seal apparatus42, the steering shaft38is inserted from the engine compartment (on the first side18of the panel10) through the first opening82, and into the chamber78. The steering gear assembly94moves with the steering shaft38, and the housing98contacts the first portion50of the boot46. As the steering shaft38moves further into the chamber78, the housing98compresses the first bellows62, and the first portion50forms a seal102against the housing98. The first bellows62decouples the seal member70from loads transmitted from the housing98to the seal apparatus42during this process; accordingly, the mating of the housing98to the seal apparatus42will not significantly affect the seal74formed between the seal member70and the panel10.

The bearing86must be moved relative to the panel10and the steering shaft38in order to be sufficiently aligned with the steering shaft38to allow the steering shaft38to extend through the second opening90. The second bellows66enables movement of the bearing86relative to the panel10without significant transmission of any resultant loads to the seal member70. Accordingly, the bearing86is movable without affecting the seal74formed between the seal member70and the panel10.

As shown inFIG. 2, movement of the bearing86causes stress on the second bellows66, with resultant elastic material strain in the second portion54of the boot46. In order to maintain the position of the bearing86relative to the shaft38, a first fastening element106is mounted with respect to the bearing86. A second fastening element110is mounted with respect to the steering gear assembly94. The first fastening element106is engaged with the second fastening element110once the steering shaft38extends sufficiently through the second opening90; accordingly, the first and second fastening elements106,110restrict movement of the bearing86and the second portion54of the boot46relative to the steering shaft38and maintains the elastic strain in the bellows66.

The first and second fastening elements106,110are configured to provide a snap-fit engagement with one another when the steering shaft38is sufficiently inserted through the second opening90. More specifically, in the embodiment depicted, the first fastening element106is a hook having a surface114that is oriented approximately 45 degrees from the axis A2of the shaft38. The hook also includes a surface118that is perpendicular to the axis A2. The second fastening element110is a member that includes inclined surface122and surface126, which is perpendicular to the axis A2.

As the steering shaft38is axially moved through the opening90in bearing86, inclined surface122of the second fastening element110contacts surface114of the first fastening element, which results in a force having a radial component that elastically bends the first fastening element106radially outward. As the shaft38is further inserted through the opening90, surface122and surface114lose contact, and the first fastening element106moves radially inward with the removal of the stress caused by the force from the second fastening element110. Surface126and surface118are in contact with one another and thereby prevent axial movement of the bearing86relative to the shaft38. As shown inFIG. 1, the apparatus42includes a plurality of hook-like fastening elements106that are arranged in a circle to interact with other fastening elements like the one shown at110.

The shaft38is rotatable about axis A2relative to the fastening elements106,110and the bearing86. The bushing93sealingly contacts the shaft38. Accordingly, both openings82,90to the chamber78are sealed. Openings82,90are the only openings to the chamber78.

In the embodiment depicted, the first portion50of the boot46has a higher spring constant than the second portion54of the boot46, and may be blow-molded polyethylene. The seal member70may, for example, be a compliant rubber. The seal member70in the embodiment depicted includes a first part130that contacts the panel10inside the hole30, a second part134that contacts the first surface14of the panel10, and a third part138that contacts the second surface22of the panel10. The contact between the first part130of the seal member70and the panel10forms a first annular face seal74. The contact between the second part134of the seal member70and the first surface14forms a second annular face seal142. The contact between the third part138of the seal member70and the second surface22forms a third annular face seal146.

It should be noted that the boot46and seal member70may be a single piece or may comprise multiple connected pieces within the scope of the claimed invention.