CA2622167A1 - Seal with load enhancing bead - Google Patents

Abstract

A shaft seal is provided including a seal lip having a load enhancing bead provided at an end thereof. The bead has a triangular-shaped profile that acts to concentrate load to a small location to provide a larger contact pressure at the point of contact. If the bead wears over time, the contact area will slightly increase, but the effect of the bead will be present until completely worn off. The small area of contact also leads to less heat generation in the seal. The load enhancing bead could be applied to all types of radial shaft seals.

Description

SEAL WITH LOAD ENHANCING BEAD
FIELD
[0001] The present disclosure relates to shaft seals, and more particularly, to a shaft seal with a load enhancing bead.

BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] Current shaft seals typically include a sharp edge for a contact tip and as the seal wears, creating a flattened surface, a large contact patch develops and the loss of seal load can be significant. The larger area of contact may also lead to greater heat generation in the seal. The contact area between the lip and the shaft or a slinger and the respective load distribution tend to be sensitive to the installation tolerances thus affecting the seal performance.

SUMMARY

[0004] Accordingly, a shaft seal is provided including an annular base portion and an annular seal lip extending from the base portion. The seal lip has a sealing face defining a plane and including a main sealing surface at an end of the sealing lip. The main sealing surface includes a load enhancing raised bead having a triangular-shaped profile extending from the plane of the sealing face. The triangular-shaped profile of the raised bead includes a first generally conical side surface and a second generally conical side surface each extending at an acute angle from the plane of the sealing face.

[0005] The load enhancing bead acts to concentrate the sealing load to a small location to provide a larger contact pressure at the point of contact, resulting in improved sealing. Moreover, the contact area and the contact load distribution become less sensitive to the tolerance stack-up which is due to both seal installation and seal manufacturing variations. As the bead wears over time, the contact area will increase but the effect of the bead will still be present until completely worn off.

[0006] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0007] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0008] Figure 1 is a cross-sectional view of a shaft seal according to the principles of the present disclosure showing the seal in a "free" (shown in phantom) and an installed state; and

[0009] Figure 2 is a detailed cross-sectional view of seal lip according to the principles of the present disclosure.

DETAILED DESCRIPTION

[0010] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0011] With reference to Figures 1 and 2, a shaft seal 10 having a load enhancing bead 12 according to the principles of the present disclosure, will now be described. The load enhancing bead, according to the principles of the present disclosure, can be incorporated into a unitized seal, as illustrated, or alternatively, can be utilized in non-unitized seals. The unitized seal can include an outer case 14 to which the seal 10 is mounted and an inner case 16 which is sealingly engaged by one or more sealing lips 20, 22 which can include one or more radially inwardly extending lips, such as lip 20, or one or more axially extending lips such as lip 22.
Each of the seal lips 20, 22 extends from the annular base portion 24 of the seal which is generally adapted to be mounted to the outer case 14. The outer case can be adapted to be mounted within a fixed housing and can include elastomeric material coated thereon for providing a sealed fit with the housing. The optional inner case 16 can similarly be provided with elastomeric coating on its inside diameter for engaging a shaft for rotation therewith.

[0012] Each of the seal lips 20, 22 can be provided with a load enhancing bead 12, as will be described in greater detail herein. Each of the seal lips 20 can include a sealing face 32 which is adapted to oppose a sealing surface 34 of the inner case 16 or, alternatively, of a shaft, if the inner case 16 is not utilized. The sealing face 32 of each seal lip 20, 22 generally defines a plane and includes a main sealing surface at the end of the sealing lip 20, 22 that is defined by the raised bead 12. The raised bead 12 has a generally triangular-shaped profile extending from the plane of the seal base 32 of the seal lip 20, 22. As illustrated in Figure 2, the generally triangular-shaped profile of the raised bead includes a first generally conical side surface 40 and a second generally conical side surface 42 each extending at an acute angle from the plane 44 of the sealing face 32.

[0013] The first generally conical surface 40 has a length L1 that can be shorter, equal to, or longer than a length L2 of the second generally conical surface 42. Preferably, the first generally conical surface 40 extends to a distal end of the annular lip seal 20, 22.

[0014] The load enhancing bead 12 is applied to the sealing lip tip to concentrate the load of the seal lip to a small location to provide a larger contact pressure at the point of contact, resulting in improved sealing. As the bead wears over time, the contact area will increase, but the effect of the bead 12 will still be present until the bead is completely worn off. The load enhancing bead could be applied to many different types of radial shaft seals and should not be limited to the specific embodiment shown herein. With the triangular profile, the shape of the bead is relatively easy to tool and accommodate on an existing seal that is typically molded.

Claims (4)

What is claimed is:

1. A shaft seal comprising:

an annular base portion; and an annular seal lip extending from said annular base portion, said seal lip having sealing face defining a plane and including a main sealing surface at an end of said sealing lip, said main sealing surface including a raised bead having a generally triangular-shaped profile extending from said plane of said sealing face.

2. The shaft seal according to claim 1, wherein said generally triangular-shaped profile of said raised bead includes a first generally conical side surface and a second generally conical side surface each extending at an acute angle from said plane of said sealing face.

3. The shaft seal according to claim 2, wherein said first generally conical surface is shorter than said second generally conical surface.

4. The shaft seal according to claim 2, wherein said first generally conical surface extends to a distal end of said annular seal lip.