EP0589929B1

EP0589929B1 - Valve

Info

Publication number: EP0589929B1
Application number: EP92911457A
Authority: EP
Inventors: Robert Keith Cross; Ronald Phillips; Lukhbir Singh Panesar
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1991-06-21
Filing date: 1992-06-10
Publication date: 1997-03-26
Anticipated expiration: 2012-06-10
Also published as: DE69218598T2; CA2111986A1; EP0589929A1; WO1993000540A1; DE69218598D1; AU1907492A; CA2111986C; GB9113486D0; ES2103372T3

Abstract

A fluid control valve includes a valve member (24) movable into engagement with a seating (17) to prevent flow of fluid through the valve. An actuating member (26) is biased in one direction by a return spring (43) and is moved against the action of the return spring by the armature of an actuator (11) when the winding thereof is energised. The movement of the actuating element (26) is transmitted to the valve member through an under travel spring (25) which yields to allow continued movement of the actuating member (26) when the valve member engages the seating.

Description

This invention relates to an electromagnetically operable fluid control valve of the ON/OFF type comprising a valve member movable between open and closed positions relative to a seating, an electromagnetic device including a stator assembly carrying a winding and an armature which is moved towards the stator assembly when the winding is energised, a return spring which is stressed during movement of the armature towards the stator assembly, means coupling the armature to the valve member said means comprises an actuating element engaged by said return spring and a valve member under travel spring interposed between said actuating element and the valve member and which yields to allow continued movement of the actuating element when the valve member engages the seating.
DE-A-1194668 shows one form of such a valve in which movement of the valve member towards the seating is transmitted through a spring which yields to allow continued movement of the armature under the action of a return spring when the winding associated with the armature is de-energised. When the winding is energised the extent of movement of the valve member away from its seating is determined by the engagement of the armature with a pole piece.
The object of the present invention is to provide a control valve of the kind specified in an improved form.
According to the invention a control valve of the kind specified comprises an armature over travel spring interposed between the armature and said actuating element and stop means operable to limit the movement of the valve member away from the seating when said winding is energised, the armature over travel spring yielding to permit continued movement of the armature after said stop means has halted the movement of the valve member.
An example of a control valve in accordance with the invention will now be described with reference to the accompanying drawing which is a part sectional side elevation of the valve.
Referring to the drawing the valve comprises a valve section 10 and an actuator 11. The valve section 10 comprises a body 12 which is provided with a peripheral flange 13 which locates against the base wall of a recess 14 formed in a housing 15. The flange 13 of the body 12 is held against the base wall of the housing by an annular retaining member 15A which is screwed into the recess 14.
The valve body 12 defines an open ended blind bore 16 which adjacent its blind end defines a seating 17 which surrounds an outlet 18. Moreover, adjacent the seating there is defined an annular gallery 19 which by way of passages 20 and slots 21 formed in the body communicates with an inlet passage 22 formed in the housing 15.
Slidable in the bore 16 is a cup shaped valve member 24 the closed end of which is shaped for engagement with the seating 17.
The valve member is biased into engagement with the seating as will be explained, by a coiled compression spring 25 which engages the base wall of the valve member at one end and at its other end is located within a recess formed in the end portion of a valve actuating rod 26. The actuating rod is of stepped form with its end portion lying within the valve member being constructed as a sliding fit in the internal surface of the valve member and at its end remote from the valve member being provided with a screw thread. The valve actuating rod 26 carries a transversely extending pin 27 the end portions of which project into elongated slots 28 respectively which are formed in the wall of the valve member 24.
The retaining member 15A is provided with an internal step between which and the valve body is located a stop plate 31 which also acts to transmit the clamping force generated when the retaining member 15A is tightened within the recess 14.
The valve actuating rod 26 has a number of components mounted thereon the first of which adjacent the enlarged end portion of the rod which lies within the valve member, is a small washer 32 which extends with clearance through the central opening of the stop plate. Adjacent the washer is a reaction plate 33 and engaging the reaction plate is the end of a tubular extension of a spring abutment 34 which is engaged with the threaded portion of the actuating rod.
Engaging the outer peripheral portion of the reaction plate is an inturned flange 35 which is formed at the end of a tubular member 36 which is coupled to an armature forming part of the actuator 11. The actuator includes a stator which carries windings which are energised when as will be explained, it is required to lift the valve member from the seating.
A coiled compression spring 43 has one end engaging a tubular portion of the spring abutment 34 and its other end engaging a fixed abutment surface. Moreover, interposed between the spring abutment 34 and a pressure plate 44 which engages the inwardly extending flange 35 is a further coiled compression spring 45 which urges the flange into engagement with the reaction plate 33.
The extent of movement of the tubular member 36 and the armature when the windings of the actuator are energised, is limited by an annular stop member 47 which is engaged by an outwardly extending flange 46 on the tubular member 36. The stop member is held in position against the retaining member 15A by means (not shown) for example, the body of the actuator 11.
The various components of the valve are shown in the positions which they adopt when the windings are de-energised. It will be seen that the reaction plate 33 is in engagement with the stop plate 31 and that the valve member is in engagement with the seating. A small clearance exists between the pin 27 and the end walls of the slots 28 so that the valve member is held in engagement with the seating due to the force exerted by the spring 25 and also by the fluid pressure acting on at least the annular end of the skirt of the valve member.
When the winding is energised the force generated is transmitted to the valve actuating rod 26 through the spring 45 and the actuating rod will be lifted together with all the components which are secured thereto, against the action of the spring 43. The upward movement will eventually take up the small clearance which exists between the pin 27 and the end walls of the slots 28 and when this clearance has been taken up the valve member is moved upwardly away from the seating thereby allowing flow of fluid through the valve outlet 18. The movement of the valve member is halted by its engagement with the stop plate 31. This engagement will halt the movement of the actuating rod together with all the components connected thereto. However, continued movement of the annular member 36 and the armature can take place against the action of the spring 45, the eventual movement being halted by the engagement of the flange 46 with the stop member 47. The engagement of the flange with the stop member 47 leaves a small air gap between the faces of the armature and the stator of the actuator. Moreover, a gap will be established between the flange 35 and the reaction plate 33.
When the windings are de-energised, the spring 45 tends to move the annular member and the armature in the direction towards the seating and this movement assists the movement of the actuating rod under the action of the spring 43 towards the seating. During the movement of the actuating rod 26 the valve member 24 will engage the seating and continued movement of the actuating rod under the action of the spring 43 will take place at the same time compressing the spring 25, until the reaction plate 33 engages the stop plate 31. The inertia of the actuating rod 26 together with the components connected to it and also the annular member and the armature is absorbed by the engagement of the reaction plate 33 with the stop plate 31 and not by the engagement of the valve member with the seating. The life of the valve member and the seating is therefore extended as compared with constructions in which the engagement of the valve member with the seating halts the movement of the various components of the valve. Moreover, the small mass of the valve member substantially eliminates valve bounce which could otherwise take place without proper damping.

Claims

An electromagnetically operable fluid control valve of the ON/OFF type comprising a seating (17), a valve member (24) movable between open and closed positions relative to the seating, an electromagnetic device (11) including a stator assembly carrying a winding and an armature which is moved towards the stator assembly when the winding is energised, a return spring (43) which is stressed during movement of the armature towards the stator assembly, means coupling the armature to the valve member, said means comprising an actuating element (26) operatively connected to said return spring and a valve member under travel spring (25) interposed between said actuating element (26) and the valve member (24), said under travel spring yielding to allow continued movement of the actuating element when the valve member engages the seating, characterised by an armature over travel spring (45) interposed between the armature and said actuating element (26) and stop means (31) operable to limit the movement of the valve member away from the seating (17) when said winding is energised, the armature over travel spring (45) yielding to permit continued movement of the armature after said stop means (31) has halted the movement of the valve member.
A fluid control valve according to Claim 1, characterised by further stop means (33, 31) acting to limit the movement of the actuating element (26) under the action of the return spring (45) when the winding is de-energised, said further stop means being positioned so that the valve member (24) engages with the seating (17) before the movement of the actuating element is halted by said further stop means.
A fluid control valve according to Claim 2, characterised in that said stop means and said further stop means are defined by a stop plate (31) one face of which is engaged by the valve member (24) and the other face of which is engaged by a reaction plate (33) secured to the actuating element.
A fluid control valve according to Claim 3, characterised by a member (36) coupled to the armature and defining an inturned flange (35) located between said reaction plate (33) and one end of the armature over travel spring (45), the other end of the armature over travel spring being engaged with a spring abutment (34) secured to the actuating element.
A fluid control valve according to Claim 4, characterised by a pin and slot connection (27, 28) between said actuating element and said valve member.