Patent Application
20060169942
The present invention relates to an innovative valve seal, specifically a valve stem seal for controlling oil flow between a valve stem and a valve guide of an internal combustion engine. More particularly, this invention relates to a mechanism for enhancing the control or metering of oil flow where at least a portion of a stem engaging surface of the seal includes an orifice.
Every internal combustion engine includes at least one intake valve to permit the air/fuel mixture to enter the cylinder and at least one exhaust valve to allow the burned exhaust gases to escape. The intake and exhaust valves, along with a cylinder head gasket, must also seal a combustion chamber.
Conventional internal combustion engines have a plurality of intake and exhaust valves, generally in a one-to-one relationship. Each valve comprises a head and an integral stem reciprocally mounted in a valve guide. Those skilled in the art will appreciate that there must be some oil flow along the stem in order to lubricate the latter as it reciprocates within the guide. As wear occurs in the valve guide and valve stem interface, oil flow will increase, causing excessive oil consumption and the formation of carbon deposits within the combustion chamber.
In order to reduce oil consumption and prevent carbon deposits, as well as to maintain engine performance, various designs have been developed to control or meter the oil flow between the stem and guide members. To the extent that relatively severe operating conditions occur in the exhaust and intake valve areas, much effort has been directed to geometries of valve sealing media.
In short, it is desirable to develop a method and a geometry that enhances the metering of oil between the valve stem and the valve guide, reduces manufacturing effort, and is easy to install.
The embodiments described herein illustrate a valve stem seal having an annular valve body with an upper surface, a lower surface, and defining an aperture. The valve body is positioned for selective sealing engagement with a valve stem. At least one orifice is disposed on an inner surface of the annular valve body between the annular valve body and the valve stem. The orifice controls the rate of oil flow between the annular valve body and the valve stem.
Various aspects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the embodiments described herein, when read in light of the accompanying drawings.
The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims, and drawings, of which the following is a brief description:
Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints that will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
Referring initially to
A valve stem assembly 16 as shown in
The valve seal 10, as illustrated in
The valve seal 10 provides a “positive valve seal”, that is a seal with actual physical contact with both valve stem 12 and valve guide 14, necessary to truly seal the combustion chamber (not shown) in a valve stem area 37 as shown in
Referring to
In accordance with one aspect of the invention, orifice 40 is disposed between a first surface 42 and a second surface 44 of the inner surface 46 as illustrated in
The upper portion 26 further includes a peripheral annular groove 48 encircling the upper portion 26 of the seal body 24 and a ring retainer 50 selectively disposed within the groove 48. Ring retainer 50 serves to compress the upper portion 26 about the reciprocating valve stem 18. The lower portion 28 of the seal body 24 includes at least one lower lip 48 in sealing circumferential engagement with the valve guide 30.
In one embodiment of the invention as shown in
The lower surface 36 of the securement portion 50 includes an outwardly extending flange 52 adapted to be in operational communication with both the engine surface 54 (shown in
An embodiment of an attachment method for the securement member 50 to the valve body 26 is illustrated in
The valve seal 10 illustrated in
A method for metering oil in a valve stem assembly 16 is contemplated comprising the steps of providing a valve 22 having an annular valve stem 12, a valve keeper groove 70 at a first end, and a valve head 72 at a second end; placing a valve stem seal 10 around the valve 22, the valve stem seal 10 having an annular valve body 26 including an upper surface 34, a lower surface 36, and defining an aperture 32, the valve body 26 being in selective sealing engagement with the valve stem 12; and controlling the flow of an oil along the valve stem 12 by proving at least one orifice 40 on an inside surface 46 of the valve stem seal 10 between the annular valve body 26 and the valve stem 12. The step of controlling the flow of the oil includes placing at least one lip 38 in sealing engagement with the valve stem 12. The step of controlling the flow of the oil may also include selectively providing the orifice 40 of a shape and a size in relationship to flow requirements by a user.
The present invention has been particularly shown and described with reference to the foregoing embodiments, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
