Patent Application
20200078709
The present invention is related generally to a fluid filter assembly which has a relief valve assembly.
Many oil filters include a filtration media which is disposed in a housing and which separates the volume inside the housing into an unfiltered space and a filtered space. An anti-drainback valve is at least partially disposed in the upstream space and is configured to open to allow oil to flow from the unfiltered space to a crankcase of an engine. A bypass valve is also partially disposed in the filtered space and normally closed but is configured to selectively open to allow some oil to bypass the filtration media. Specifically, the bypass valve includes a valve plug and one or more springs that are configured to bias the valve plug into a closed condition and to only allow the valve plug to open, thereby allowing some fluid to flow directly from the unfiltered space to the filtered space, in response to oil pressure in the unfiltered space exceeding a predetermined threshold pressure.
One aspect of the present invention is related to a fluid filter assembly for filtering a fluid. The fluid filter assembly includes a container that surrounds an enclosed volume. A filter media is disposed in the enclosed volume and partially divides it into an unfiltered space and a filtered space. The filter media encircles and extends along a central axis. A bypass valve assembly is disposed at one axial end of the filter media. The bypass valve assembly includes an end cap and a valve housing, which has a through opening. The end cap is in engagement with an end face of the filter media to force the fluid to flow through the filter media in a radial direction. The bypass valve assembly further includes a valve plug which has a head portion and a tail portion. The valve plug is biased into a closed position by a compression spring and is moveable against a spring force from the compression spring from the closed position to an open position to allow the fluid to flow directly from the unfiltered space to the filtered space. The head portion is disposed in the filtered space, and the tail portion extends through the through opening into the unfiltered space. The valve housing and the end cap are made as a monolithic piece.
In other known fluid filter assemblies, the end cap and the valve housing are made as separate pieces from one another and are subsequently joined together. Making the valve housing and end cap as a monolithic piece reduces part waste since material does not have to be removed from a central area of the end cap, as is common. Making the valve housing and end cap as a monolithic piece also reduces the total number of parts in the oil filter assembly, thereby reducing manufacturing time and costs. Also, by making the valve housing and end cap monolithic, this eliminates the metal to metal contact between these components which is common in the industry.
According to another aspect of the present invention, the valve housing has a cylindrical wall, and the tail portion of the valve plug is disposed in an area of the cylindrical wall in both the closed position and in the open position.
According to yet another aspect of the present invention, the tail portion of the valve plug is in a clearance fit relationship with the cylindrical wall of the valve housing.
According to still another aspect of the present invention, the tail portion includes at least two fingers, and each of the fingers presents a notch for receiving one end of the compression spring.
According to yet a further aspect of the present invention, the valve housing defines a spring seat which supports an opposite end of the compression spring from the fingers.
According to still a further aspect of the present invention, the fingers have radially outer-most portions which remain within an area surrounded by the cylindrical wall as the valve plug moves from the open position to the closed position.
According to another aspect of the present invention, the valve housing has a top wall which extends radially inwardly from the end cap.
According to yet another aspect of the present invention, a retainer spring extends from the top wall of the valve housing to an inner surface of the container.
Another aspect of the present invention is related to a method of making an oil filter assembly. The method includes with the step of inserting a compression spring into the valve housing. The method includes with the step of inserting a tail portion of a valve plug into a through opening in the valve housing and engaging the tail portion with the compression spring to bias the valve plug into a closed position wherein a head portion of the valve plug covers the through opening. The method includes the step of preparing a filter media which encircles a central axis. The method includes with the step of fixedly attaching an end cap and a valve housing, which are constructed a single monolithic piece, with an axial end of the filter media. The method includes with the step of inserting the filter media into an enclosed space of a container.
One advantage to the method according to this aspect of the present invention is that the step of locating a valve with a valve housing with an end cap and then fixedly attaching these components together is eliminated. Thus, oil filter assembly can be assembled more quickly and at a lower cost than other known oil filter assemblies.
According to another aspect of the present invention, the valve housing has a cylindrical wall, and the tail portion of the valve plug is in a clearance fit relationship with the cylindrical wall such that the cylindrical wall guides movement of the valve plug between the closed position and an open position.
According to yet another aspect of the present invention, the tail portion of the valve plug includes a two or more fingers, and the step of inserting the tail portion into the through opening includes flexing the fingers.
According to still another aspect of the present invention, the end cap and valve housing are made of metal, and the valve plug is made of plastic.
According to a further aspect of the present invention, the valve housing has a top wall.
According to yet a further aspect of the present invention, the method further includes the step of inserting a retainer spring into the unfiltered space and such that the retainer spring contacts the top wall of the valve housing and an inner surface of the container.
These and other features and advantages of the invention will become more readily appreciated when considered in connection with the following description of the presently preferred embodiments, appended claims and accompanying drawings, in which:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, one aspect of the present invention is related to an improved fluid filter assembly 20. In the exemplary embodiment, the fluid filter assembly 20 is a spin-on oil filter assembly 20 for filtering contaminants out of the oil of an internal combustion engine, such as in an automobile. While the following discussion is related to the use of the fluid filter assembly 20 as an oil filter, it should be appreciated that the fluid filter assembly 20 could be configured for use with any suitable type of fluid (e.g., water, gasoline, diesel fuel, etc.) and in any suitable application.
With reference to
The canister 22, the tapping plate 24, the filer media 28, and center tube 34 may be made of any suitable materials. For example, the canister 22, tapping plate 24, and center tube 34 can be made of metal, and the filter media 28 can be made of a range of different materials that are capable of filtering contaminants out of engine oil.
The tapping plate 24 includes a single fluid outlet orifice 36 and a plurality of fluid inlet orifices 36. The fluid outlet orifice 36 is located on the central axis A and is configured to convey oil from the filtered space 30 back to the engine. The fluid inlet orifices 38 are spaced radially outwardly of the fluid outlet orifice 36 and are spaced circumferentially from one another around the central axis A. The fluid inlet orifices 38 communicate with the unfiltered space 32 in the canister 22 for conveying oil from the engine to the unfiltered space 32 during operation of the engine.
The oil filter assembly 20 further includes an anti-drainback valve 40 in the form of a resilient flap which opens to allow oil to flow into the unfiltered space 30 when the engine is running and closes to prevent oil from escaping out of the unfiltered space 30 when the engine is off. Specifically, the anti-drainback valve 40 opens only in response to the pressure of the oil at the fluid inlet orifices 38 exceeding the pressure of the oil in the unfiletered space 30 by a threshold and automatically closes when that pressure difference falls below the threshold. The anti-drainback valve 40 is preferably made of silicon but any suitable resilient material may be employed.
During normal operation of the engine, oil is conveyed by an oil pump (not shown) to the fluid inlet orifices 38, past the anti-drainback valve 40 and into the unfiltered space 32. The oil then passes through the filter media 28, and into the filtered space 30. The filtered oil then travels through the fluid outlet orifice 36 so that it can be guided back to a crankcase in the engine. In certain conditions, such as when the filter media 28 becomes clogged or when the viscosity of the oil exceeds a viscosity threshold of the filter media 28, insufficient oil is able to flow through the filter media 28. In those conditions, a bypass valve assembly 42 opens to allow some oil to flow directly from the unfiltered space 32 to the filtered space 30, thereby ensuring a continuous flow of oil out of the oil filter assembly 20 and to the engine. As discussed in further detail below, the opening and closing of the bypass valve assembly 42 occurs automatically without any electronic sensors or other costly components.
In the exemplary embodiment, the bypass valve assembly 42 is positioned on an opposite side of the filter media 28 from the tapping plate 24. As shown in
The end cap 46 is annular in shape and is positioned on one end face of the filter media 28 to force the oil in the unfiltered space 30 to only flow through the filter media 28 in a radial direction, thereby ensuring proper filtering of the oil. The end cap 46 includes inner and outer shoulders 48, 50 which are spaced from one another in the radial direction. The inner shoulder 48 may be in contact with the center tube 34, and the outer shoulder 50 may be in contact with the outer peaks of the filter media 28. The end cap 46 is preferably bonded with the end face of the filtered media 28 with an adhesive.
The valve housing 44 has a top wall 52, a cylindrical wall 54, and a bottom wall 56. The top wall 52 extends radially inwardly (i.e., in a plane which lies perpendicular to the central axis A) from a lower end of the inner shoulder 46 to the cylindrical wall 54. The cylindrical wall 54 extends in an axial direction towards the tapping plate 24. The bottom wall 56 extends radially inwardly from a lower end of the cylindrical wall 54 to a through opening.
The bypass valve assembly 42 further includes a valve plug 58 which extends through the through opening and can be sealed against the bottom wall 56. The valve plug 58 includes a head portion 60 and a tail portion 62. The head portion 60 is generally circular in shape and has an outer diameter that is greater than a diameter than the through opening in the bottom wall 56. The tail portion 62 includes at least two diametrically opposed fingers 64, each of which extends from the head portion 60 to an end region 66. Each of the fingers 64 is generally shaped like a check-mark and presents a downwardly facing notch 68.
The downwardly facing notches 68 of the fingers 64 and the bottom wall 56 of the valve housing 44 define spring seats for a compression spring 70 which acts on the valve plug 58 to bias the valve plug 58 into a closed position such that the head portion 60 covers the through opening in the bottom wall 56. Thus, when the valve plug 58 is in the closed position, oil is restricted from passing directly from the unfiltered space 32 to the filtered space 30 without passing through the filter media 28. The compression spring 70 is preferably a coil spring and is preferably made of a spring steel material.
As shown in
During operation of the engine, if the pressure of the oil in the unfiltered space 32 of the canister 22 exceeds the pressure of the oil in the filtered space 30 by a predetermined amount (which is determined by the stiffness of the compression spring 70 and the size of the through passage of the valve housing 44), then the valve plug 58 will be urged against the force of the compression spring 70 from the closed position to an open position (shown in
The radially outer-most portions of the fingers 64 are in a clearance fit relationship with the cylindrical wall 54 of the valve housing 44 such that the cylindrical wall 54 guides the valve plug 58 as it automatically moves between the open and closed positions.
The valve plug 58 is preferably made of a non-metallic material, such as plastic, such that there is no metal to metal scraping contact within the bypass valve assembly 42.
Referring now to
Another aspect of the present invention is related to a method of making fluid filter assembly 20, such as the oil filter assembly 20 shown in
In the exemplary embodiment, the step of inserting the tail portion 62 into the through opening includes flexing the fingers 64 inwardly (i.e., towards one another and towards the central axis A).
Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. Additionally, it is to be understood that all features of all claims and all embodiments can be combined with each other as long as they do not contradict each other. It is to further be understood that directional terms, such as “upper”, “top”, and “bottom” are in reference to the orientations of the various features of the oil filter assembly in the drawings and are not intended to require any particular orientation.
