BERNDORFER, Axel (15 Schulstrasse, Nittel, 54453, DE)
HAMDI, Nordine (13 rue de Limpach, Sanem, L-4986, LU)
BERNDORFER, Axel (15 Schulstrasse, Nittel, 54453, DE)
CLAIMS
1. An oil control valve having an integrated check valve arrangement, the check valve arrangement comprising a valve seat provided with at least an aperture there through, a resilient ring of a lesser depth than the or each aperture, filter means around the resilient ring, the filter means comprising a perforated area corresponding to the resilient ring depth wherein the resilient ring is actuable, upon selected pressure imbalance in fluid present in the check valve, between an open position in which the resilient ring abuts against a seat portion of the check valve in order to allow fluid to flow through the filter means, and a closed position in which the resilient ring abuts against the inner circumference of the filter means thereby closing said perforations in order to substantially prevent flow of fluid there through.
2. An oil control valve according to claim 1 , wherein the resilient ring comprises an annular band of material which forms a partial ring having a break between each end of the partial ring.
3. An oil control valve according to claims 1 and 2, wherein the resilient ring further comprises a portion of narrowed dimension in order to form a relatively weak portion of the ring such that a hinge function is provided.
4. An oil control valve according to any preceding claim, wherein the valve seat portion of the check valve housing is provided with annular locating ribs at either end thereof in order to locate the resilient ring on the valve seat portion.
5. An oil control valve according to claim 4, wherein the annular locating ribs are provided with a recess or protrusion adapted to cooperate with a corresponding recess or protrusion on the resilient ring.
6. An oil control valve according to any preceding claim, wherein the filter means comprises a thin film screen member in the form of an annular band of material where the perforated area is provided around said band of material.
7. An oil control valve according to claim 6, wherein the perforated area corresponds to the resilient ring depth.
8. An oil control valve according to any preceding claim, wherein the filter means and resilient ring are moveably secured to one another.
9. An oil control valve according to claim 8, wherein the filter means and resilient ring are joined by a weld, such as a laser weld, at a point location in order to moveably secure the filter means to the resilient ring.
10. An oil control valve according to claim 9, wherein the point location is located at or toward the narrowed dimension of the resilient ring.
11. An oil control valve according to any preceding claim, wherein the valve seat comprises a series of apertures spaced around the circumference of the valve seat.
12. An oil control valve according to claim 11 , wherein four apertures are provided, each equally spaced apart from one another around the circumference of the valve seat.
13. An oil control valve according to any preceding claim, wherein the resilient ring and check valve seat allow flow of fluid in a first direction due to the pressure of fluid outside the check valve acting on the outer diameter of the resilient ring in order to cause the resilient ring to decrease in diameter such that fluid may flow through the filter means, around the resilient ring and through a portion of the or each aperture not obstructed by the resilient ring.
14. An oil control valve according to claim 13, wherein the resilient ring and filter means further substantially prevent flow in a second direction due to the resilience of the resilient ring and pressure balance between the inside and outside of the check valve which causes the resilient ring to increase in diameter until it abuts against the inner diameter of the filter means perforated area in order to close the perforations in the filter means to fluid flow. |
"Oil Control Valve"
The present invention relates to an oil control valve, particularly, but not exclusively, an oil control valve used to control the flow of oil to ports of an automobile variable cam phaser.
In automobile variable cam phasers, as well as in other areas, oil control valves (OCVs) are commonly used to control flow of oil. In order to improve the performance of a variable cam phaser at relatively low oil pressure, it is often necessary to provide check valves. Typical check valves suitable for this purpose include ball and seat or ring actuated check valves. A typical ring actuated check valve is described in German patent publication no. DE 102005013085 B3 to Hydraulik-Ring GmbH. As well as a check valve, a filter is normally provided in line with the OCV {typically in the cylinder head).
A disadvantage of having a discrete OCV, filter and check valve is that the cylinder head machining required can be relatively extensive since the check valve is normally actually provided on the cylinder head. Furthermore, servicing of the various individual components can be relatively difficult.
According to the present invention there is provided an oil control valve having an integrated check valve arrangement, the check valve arrangement comprising a valve seat provided with at least an aperture there through, a resilient ring of a lesser depth than the or each aperture, filter means around the resilient ring, the filter means comprising a perforated area corresponding to the resilient ring depth wherein the
resilient ring is actuable, upon selected pressure imbalance in fluid present in the check valve, between an open position in which the resilient ring abuts against a seat portion of the check valve in order to allow fluid to flow through the filter means, and a closed position in which the resilient ring abuts against the inner circumference of the filter means thereby closing said perforations in order to substantially prevent flow of fluid there through.
Preferably, the resilient ring comprises an annular band of material which forms a partial ring having a break between each end of the partial ring. More preferably, the resilient ring further comprises a portion of narrowed dimension in order to form a relatively weak portion of the ring such that a hinge function is provided.
Preferably, the valve seat portion of the check valve housing is provided with annular locating ribs at either end thereof in order to locate the resilient ring on the valve seat portion. Preferably, the annular locating ribs are provided with a recess or protrusion adapted to co-operate with a corresponding recess or protrusion on the resilient ring. This prevents the check valve arrangement from freely rotating around the valve seat.
Preferably, the filter means comprises a thin film screen member in the form of an annular band of material where the perforated area is provided around said band of material. More preferably, the perforated area corresponds to the resilient ring depth.
Preferably, the filter means and resilient ring are moveably secured to one another. More preferably, the filter means and resilient ring are joined by a weld, such as a laser weid, at a point location in order to moveably
secure the filter means to the resilient ring. Preferably, the point location is located at or toward the narrowed dimension of the resilient ring.
Preferably, the valve seat comprises a series of apertures spaced around the circumference of the valve seat. Optionally, four apertures are provided, each equally spaced apart from one another around the circumference of the valve seat.
Preferably, the resilient ring and check valve seat allow flow of fluid in a first direction due to the pressure of fluid outside the check valve acting on the outer diameter of the resilient ring in order to cause the resilient ring to decrease in diameter such that fluid may flow through the filter means, around the resilient ring and through a portion of the apertures not obstructed by the resilient ring. More preferably, the resilient ring and filter means further substantially prevent flow in a second direction due to the resilience of the resilient ring and pressure balance between the inside and outside of the check valve which causes the resilient ring to increase in diameter until it abuts against the inner diameter of the filter means perforated area in order to close the perforations in the filter means to fluid flow.
Embodiments of the oil control valve according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-
Fig. 1 is a perspective illustration of the oil control valve having a check valve according to the present invention;
Fig. 2 is a cross sectional view of the check valve portion of the oil control vaive of Fig. 1 taken through the line A-A where the check valve is in a closed position;
Fig. 3 is a cross sectional view of the check valve portion of the oil control valve of Fig. 1 taken through the line A-A where the check valve is in an open position;
Fig. 4 is a perspective illustration of the check valve housing separated from the oil control valve and without the resilient ring and filter means; Fig. 5 is a perspective illustration of the check vaive housing separated from the oil control valve with the resilient ring and filter means wrapped there around;
Fig. 6 is a schematic illustration of the arrangement of the resilient ring member relative to the filter means; and
Fig. 7 is a perspective illustration of the resilient ring and filter means removed from the check valve.
Fig. 1 shows an oil control valve (OCV) 10 for mounting in the location of a variable cam phaser via a connection bracket 14. The OCV 10 is provided with a check valve housing 12 at its lower end.
The check valve housing 12 has a pair of annular locating ribs 16 between which a valve seat of the OCV, in the form of a cylindrical barrel, is provided. The valve seat has a number of apertures A spaced there around, in the example shown a series of four apertures A are provided. This is best seen in Figs. 2 to 4.
Annular ribs 16 have a pair of opposing recesses 30 and corresponding protrusions extending from the resilient ring 20 and filter means 22. These co-operate to avoid free rotation around the check valve housing 12.
A flow actuated valve arrangement 18 comprising a resilient ring 20 and filter means 22 is placed around the valve seat of the OCV 10. The resilient ring 20 and filter means 22 are joined to one another during
manufacture by point welding W. The resilient ring is preferably biased toward a closed position where it has a relatively large diameter and abuts against the inner circumference of the filter means when no fluid pressure imbalance is present. In the embodiment shown, the filter means 22 comprises a thin film screen filter having an area of perforations there around. The filter means has a relatively large depth D1 with a band of perforations covering a depth D2 and extending around the filter means 22. The depth D2 roughly corresponds to the depth of the resilient ring 20.
A hinge 24 is effectively created on the resilient ring 20 by joining opposite halves of the spring by a portion 24 having a substantially narrower diameter than the rest of the resilient ring. This creates an intentional weakness in the spring at that point which increases it's resilience and allows it to be bent easily in order to assist installation and improve operation when installed on the OCV. The resilient ring 20 extends around the OCV 10 but does not actually join together to form a full circle. Instead, a small gap 28 remains; the purpose of this gap is discussed subsequently. In contrast, the filter means 22 forms a complete circle which extends all of the way around the valve seat of the OCV 10 in order to ensure proper filtering of oil. The resilient ring has a depth D2 which is relatively shallow compared to the depth D1 of the filter means. The purpose of this is discussed subsequently.
In order to minimise any pressure loss as a result of the apparatus, when the flow actuated valve arrangement 18 is positioned in the OCV 10, the weld point W is aligned such that it is fixed between two of the apertures A, as shown in Fig. 2. With the exception of the small areas of the resilient ring 20 and filter means 22 which are actually welded together at the welding point W, the retainer spring 20 and filter means may move {expand and contract) independently of one another.
As represented by arrow F in Fig. 4, the check valve housing 12 provides a flow path there through which allows flow of oil (from outside the check valve housing 12, through the filter means perforated area and into the apertures A (around the gap created between the relatively shallow resilient ring and the relatively large apertures A) but does not allow flow of fluid in the opposite direction from within the check valve housing 12 through the filter means. The mechanics of the check valve 12 which provide this function will become apparent from the subsequent discussion.
In use, and with reference to Fig. 2, oil flowing into the closed check valve housing 12 will exert pressure, against the outer circumference of the resilient ring 20. This causes the resilient ring 20 to contract slightly thereby opening the perforated area to fluid flow. Fluid can then flow through the perforated area and into the check valve housing 12 via the relatively large diameter apertures A. The contraction is assisted by the hinged portion 24 of the resilient ring 20. Oil can also flow into the gap 28 between the ends of the resilient ring 22.
The pressure of any fluid attempting to flow in the opposite direction back through the check valve (i.e. in the direction opposite to that represented by F of Fig. 4) will (along with the resilience of the resilient ring) push the resilient ring 20 against the inner circumference of the filter means 18. Once pressed against the filter means in this way, no flow of fluid may pass through the perforated area and flow in this direction is therefore prevented.
The valve described therefore has the same ability to control oil flow directions as typical check valves; however, it has the great advantage of
allowing the check valve and a filter to be incorporated into the actual OCV body.
Modifications, and improvements may be made to the foregoing without departing from the scope of the invention.