WO2008034879A1

WO2008034879A1 - Oil control valve

Info

Publication number: WO2008034879A1
Application number: PCT/EP2007/059977
Authority: WO
Inventors: Axel H. Berndorfer
Original assignee: Delphi Technologies, Inc.
Priority date: 2006-09-22
Filing date: 2007-09-20
Publication date: 2008-03-27
Also published as: GB0618648D0

Abstract

Oil control valve (10) having an integrated check valve arrangement, the check valve arrangement (18) comprising a valve seat provided with at least an aperture (A) there through, a resilient ring (20), filter means (22) around the resilient ring comprising a perforated area, 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 (20) abuts against the seat portion of the check valve, and a closed position in which the resilient ring abuts against the inner circumference of the filter means (22) thereby closing said perforated area. The valve seat has a longitudinal axis radially offset from the longitudinal axis of the valve body such that an enlarged annular portion is provided in a portion of the valve adjacent an actuable portion of the resilient ring in order to allow the actuable portion of the resilient ring to actuate therein.

Description

"Oil Control Valve" Technical Field

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.

Background of the invention

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. The components of such check valves must also be highly durable since they are continually being subjected to a series of pressure change cycles.

Summary of the invention

According to the present invention there is provided an oil control valve body 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, 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 the 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 perforated area in order to substantially prevent flow of fluid there through, wherein the valve seat has a longitudinal axis radially offset from the longitudinal axis of the valve body such that an enlarged annular portion is provided in a portion of the valve adjacent an actuable portion of the resilient ring in order to allow the actuable portion of the resilient ring to actuate therein.

The radially offset valve seat has the advantage of providing at one side of the valve a good location point for sandwiching the filter and resilient ring between the valve seat and body as well as providing at the other side of the valve an annulus which allows the resilient ring to expand and contract as required.

Preferably, the or each aperture is longitudinally offset from the resilient ring.

This minimises any tendency for the resilient ring to bend into the apertures when it is forced under pressure against the valve seat.

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 sandwiched portion at one side of the check valve in order to moveably secure the filter means to the resilient ring. Preferably, the sandwiched portion is located at or toward the narrowed dimension of the resilient ring and toward the side of the check valve nearest the offset longitudinal axis of the valve seat.

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 apertures are staggered in the longitudinal direction 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 perforated area in the filter means to fluid flow.

Brief Description of the drawings 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 perspective illustration of the check valve housing separated from the oil control valve with the resilient ring and filter means wrapped there around;

Fig. 3A is a cross sectional view of the check valve portion of the oil control valve of Fig. 1 where the resilient ring is illustrated in its expanded

(solid line) and contracted (dashed line) positions; and

Fig. 3B is a further schematic transverse view of the check valve of Fig. 1.

Description of the preferred embodiment 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 a staggered arrangement. In the example shown a series of four apertures A are provided. This is best seen in Fig. 3B.

As shown in Fig. 3A, the walls of the valve seat are fashioned to provided a valve seat having a longitudinal axis which is offset from the longitudinal axis of the valve body by a distance D.

Annular ribs 16 have a pair of opposing recesses 30 and corresponding protrusions 31 extending from a resilient ring (or lamella) 20 and filter means 22. These co-operate to avoid free rotation around the check valve housing 12.

A flow actuated valve arrangement 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 sandwiching them between the valve seat and the valve body at the location X in Fig. 3A. 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 with a band of perforations extending around the filter means 22, the depth of perforations roughly corresponds to the depth of the resilient ring 20.

A hinge (not shown) is effectively created on the resilient ring 20 by joining opposite halves of the ring by a portion having a substantially narrower diameter than the rest of the resilient ring. This creates an intentional weakness in the ring 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 which is relatively shallow compared to the depth 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 sandwiching point X is aligned such that it is fixed between two of the apertures A, as shown in Fig. 3A. With the exception of the small areas of the resilient ring 20 and filter means 22 which are actually sandwiched together at X, the resilient ring 20 may move (expand and contract) independent of the filter means 22. In this regard, the offset nature of the valve seat longitudinal axis results in a relatively large gap G which desirably allows the resilient ring to expand and contract by a relatively large amount.

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 (assisted by the staggered arrangement of the 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 (from the position indicated by a solid line to the position indicated by the dashed line in Fig, 3A) thereby opening the perforated area in the filter means 22 to fluid flow. Fluid can then flow through the perforated area and into the check valve housing 12 via the staggered apertures A. The contraction is assisted by the hinged portion of the resilient ring 20. Initially oil can also flow into the gap 28 between the ends of the resilient ring 22 although this is eventually prevented once the ring 20 is fully abutted against the valve seat.

The pressure of any fluid attempting to flow in the opposite direction back through the check valve will (along with the resilience of the resilient ring) push the resilient ring 20 against the valve seat. 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. In this regard, the valve seat assists in preventing fatigue damage to the ring 20 by providing support therefore. The staggered apertures A also minimise the likelihood of the ring 20 being forced and bent into the apertures under the force of the fluid pressure.

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. Furthermore, it minimises any fatigue on the resilient ring as a result of exposure to repeated pressure cycles.

Modifications, and improvements may be made to the foregoing without departing from the scope of the invention.

Claims

1. An oil control valve, particularly for controlling the flow of oil to ports of an automobile variable cam phaser, the body of the 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, 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 the 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 perforated area in order to substantially prevent flow of fluid there through, wherein the valve seat has a longitudinal axis radially offset from the longitudinal axis of the valve body such that an enlarged annular portion is provided in a portion of the valve adjacent an actuable portion of the resilient ring in order to allow the actuable portion of the resilient ring to actuate therein.

2. The oil control valve according to claim 1 wherein the aperture is longitudinally offset from the resilient ring.

3. The oil control valve according to claim 1 or 2, 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.

4. The oil control valve according to anyone of the preceding claims, 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.

5. The oil control valve according to anyone of the preceding claims, 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.

6. The oil control valve according to claim 5, 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.

7. The oil control valve according to anyone of the preceding claims, 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.

8. The oil control valve according to anyone of the preceding claims, wherein the filter means and resilient ring are moveably secured to one another.

9. The oil control valve according to claim 8, wherein the filter means and resilient ring are joined by a sandwiched portion at one side of the check valve in order to moveably secure the filter means to the resilient ring.

10. The oil control valve according to claim 9, wherein the sandwiched portion is located at or toward the narrowed dimension of the resilient ring and toward the side of the check valve nearest the offset longitudinal axis of the valve seat.

11. The oil control valve according to anyone of the preceding claims, wherein the valve seat comprises a series of apertures spaced around the circumference of the valve seat.

12. The oil control valve according to claim 11 , wherein the apertures are staggered in the longitudinal direction around the circumference of the valve seat.