Patent Application
20170167316
An engine valve stem seal assembly is disclosed. More particularly, an end reinforced engine valve stem seal assembly is disclosed.
For an engine, a valve stem seal assembly cooperates with an engine valve stem to provide lubrication and to contain engine gases within engine inlet and exhaust ports. To accomplish these functions, such an engine valve stem seal assembly typically includes an elastomeric seal that provides an elastomeric-to-metal seal between the engine elastomeric seal and the engine valve stem.
An inner surface 138 of the transition area 136 engages an upper surface 140 of the first diameter 137 of the valve guide 22. The valve stem seal 126 engages the outer circumference 54 of the valve stem 20 to provide a seal. An outer circumference 158 of the seal 126 is supported by and engages an inner circumference of the upper retainer portion 134. The valve stem seal 126 includes an upper seal 160 and a lower seal 162. The upper seal 160 includes an inner surface 145 that engages an upper surface 147 of the second diameter 139 of the valve guide 22. The retainer lower portion 130 has a valve spring 24 disposed therearound. The valve spring 24 rests on and cooperates with an integral flange 43 to maintain the seal 126 in position on the valve guide 22. Under high pressure conditions, the valve spring 24 tends to prevent the guide 22 from being lifted, which can result in seal failure due to bursting.
Unfortunately, the cylindrical-shaped foundation retainer 128 of the '143 patent has a limited sealing effect in an axial direction by allowing the elastomeric seal 126 to partially axially extrude when pressure is applied under the elastomeric seal 126. Such cylindrical-shaped foundation seal support assemblies only partially solve the problem of leakage in the axial direction into which the elastomeric seal 126 partially extrudes. Consequently, the cylindrical-shaped foundation arrangement has limited strength in the axial direction by allowing the elastomeric seal 126 to shear and partially extrude when pressure is applied under the elastomeric seal 126.
Therefore, what is sought is a valve stem seal assembly whose elastomeric seal does not extrude, thereby providing a low oil metering rate performance and better containment of engine gases in the axial direction, than existing one-piece cylindrical-shaped foundation valve stem seal assemblies.
A valve stem seal assembly has an elastomeric seal with first and second radially inwardly directed sealing lips that are in intimate sealing contact with a valve stem. The valve stem seal assembly has a metal seal retainer with a first metal seal retainer portion disposed on a first top portion of the elastomeric seal. The first metal seal retainer portion radially abuts a second top portion of the elastomeric seal and is bonded thereto, wherein no portion of the elastomeric seal is axially above the first metal seal retainer portion. Also, the valve stem seal assembly has a second metal seal retainer portion that is unitary with and perpendicular to the first metal seal retainer portion, wherein an outer surface of the elastomeric seal is bonded to an inner surface of the second metal seal retainer portion. No portion of the elastomeric seal is radially outward of the second metal seal retainer portion.
Further objects and advantages of the present invention will be apparent from the following description and appended claims, reference being made to the accompanying drawings forming a part of a specification, wherein like reference characters designate corresponding parts of several views.
It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise.
The valve stem seal assembly 10 has a second metal seal retainer portion 28 that is continuous and unitary with, and perpendicular to, the first metal seal retainer portion 23. As shown, the metal seal retainer 21 is essentially of the same thickness throughout, but could vary in thickness depending on the application. The metal seal retainer 21 further comprises the first and second metal seal retainer portions 23, 28, wherein the metal seal retainer 21 extends up the full vertical height of the valve stem seal assembly 10 and over the top of the first top portion 24 of the elastomeric seal 12. Thereby, the metal seal retainer 21 supports the elastomeric seal 12 and prevents axial extrusion thereof. The prior art valve stem seal assembly of the '143 patent, which is illustrated in
Further, an outer surface 30 of the elastomeric seal 12 is bonded to an inner surface 32 of the second metal seal retainer portion 28, and, except for a retainer flang 47, no portion of the elastomeric seal 12 is radially outward of the metal seal retainer 21. As
In relationship to the second metal seal retainer portion 28, the first metal seal retainer portion 23 extends radially inward. Also, the first metal seal retainer portion 23 extends horizontally at least halfway inward of the horizontal width of the elastomeric seal 12, just above the first radially inwardly directed sealing lip 14.
The first metal seal retainer portion 23, in conjunction with a much smaller exposed width of the second top portion 26 of the elastomeric seal 12 (as compared to the fully exposed width of the top of seal 126 of the '143 patent that is illustrated in
It is much more common to have a valve guide step 50 machined in the valve guide 40 that extends outward a bit further under the lowest extent of the seal 12, as the first valve stem assembly 10 is structured. However, a second valve stem seal assembly 10′, as illustrated in
In accordance with the provisions of the patent statutes, the principles and modes of operation of this invention have been described and illustrated in its preferred embodiments. However, it must be understood that the invention may be practiced otherwise than specifically explained and illustrated without departing from its spirit or scope.
| Number | Date | Country | |
|---|---|---|---|
| 62267362 | Dec 2015 | US |
