GB2255616A

GB2255616A - Electro- magnetically operable valve

Info

Publication number: GB2255616A
Application number: GB9110216A
Authority: GB
Inventors: Andrew Roger Knight
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1991-05-10
Filing date: 1991-05-10
Publication date: 1992-11-11
Also published as: GB9110216D0

Abstract

An electro-magnetically operable fluid control valve has a pair of valve components 18, 22, the component 18 being slidable in a bore 11 of a supporting body. The component 18 is secured to an armature 17 associated with a solenoid 15 mounted on the supporting body. The component 22 is slidable in a further bore 19 formed in the component 18, the further bore defining part of the flow path, 27 to 21, of the valve and defining a seating engagable by the component 22. Attached to the component 22 is a cross bar 24 which is engagable with a stop surface to limit the upward movement of the component 22. When the solenoid is energised the component 18 moves upwardly so that the seating is engaged with the component 22 to prevent fluid flow. In a second embodiment Fig. 3 (not shown) the operation of the two valve components is reversed with the outer component being fixed and the inner component secured to an armature (29). <IMAGE>

Description

ELECTRO-MAGNETICALLY OPERABLE VALVE This invention relates to electro-magnetically operable fluid control valves including a solenoid and an armature, the armature being coupled to a movable component of the valve.

Examples of valve in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a section through one example of the valve, Figure 2 is a section on the line A-A of Figure 1, and Figure 3 shows another example of the valve.

The valves illustrated are intended to form the spill valve of a high pressure fuel injection pumping apparatus for supplying fuel to a compression ignition engine nevertheless it will be appreciated that the valve constructions to be described can be applied to any form of on/off type fluid control valve.

Referring to Figures 1 and 2 the valve comprises a valve body 10 which conveniently in the application of the valve to a fuel pumping apparatus, forms part of the body of the apparatus. Formed in the body 10 is a bore 11 which opens into a stepped chamber 12 which is defined in a housing 13 which is secured to the body 10. Also provided is a solenoid which is contained within a solenoid casing 14 which is secured against the face of the housing 13 by means of bolts (not shown) which conveniently extend to the body 10. As more clearly seen in Figure 2, the solenoid comprises an "E" core 15 about the centre limb of which is wound a winding 16.

Associated with the solenoid is an armature 17 which is movable towards and away from the armature by the fact that it is mounted on one component 18 of the valve. The component 18 is of cylindrical form and is slidable within the bore 11. The component extends through the wider portion of the chamber and formed in the component 18 is a blind stepped bore 19. The blind end of the bore is remote from the armature and it is connected by means of an inclined drilling 20 to a passage 21 which is formed in the body 10. The step in the bore 19 forms a seating for the other component 22 of the valve which is shaped to cooperate with the seating and is of cylindrical form.It extends from the bore 19 into a transverse slot 23 which is formed in the component 18 and at its end remote from the seating there is mounted a cross-bar 24 between which and the component 18 is located a coiled compression spring 25.

Adjacent the seating on the side thereof remote from the blind end of the bore, there is formed in the bore a circumferential groove 26 and this communicates by way of a further drilling in the component 18 with a passage 27 formed in the body 10. The passage 27 in use is connected with the pumping chamber of the associated fuel pumping apparatus and the passage 21 to a drain.

When the solenoid is de-energised the spring acts to urge the two components relative to each other thereby separating the component 22 from the seating to allow flow of fuel between the passages 27 and 21. This flow of fuel will normally occur during inward movement of the pumping plunger of the apparatus and the flow of fuel represents spillage of fuel from the pumping chamber.

The movement of the armature and the component 18 is limited by a stop not shown. When the solenoid is energised the armature will move towards the solenoid and the cross-bar 24 will engage the step in the chamber 12 so that movement of the component 22 will be halted.

Before the armature engages the solenoid but after the cross-bar 24 has engaged the step, the component 22 and the seating are brought into engagement thereby preventing further flow of fuel. The practical effect of this is that the apparatus will start to deliver fuel to the associated engine and this can continue until the solenoid is de-energised whereupon the components 18 and 22 will move relative to each other to allow the flow of fuel between the passages 21 and 27 to take place. Some leakage of fuel into the chamber 12 is to be expected and this chamber can be vented to the drain.

Turning now to Figure 3 of the drawings the valve body 10 which again can be the casing of a fuel pumping apparatus has secured within a recess formed in it one component 27 of the valve which component is similar to the component 18 of Figure 1. The other component 28 of the valve is similar to the component 22 of the example shown in Figure 1 but in this case it is the component 28 which is connected to the armature 29. The armature 29 is in the form of an "E" core which is presented to the similarly constructed core 30 of the solenoid. The centre limb of the core 30 is surrounded by the winding 16 but in this case the former for the winding 16 has a projection which extends about the centre limb of the armature and which has a further winding 31 wound about it. In order to close the valve the windings 16 and 31 are energised in such a way that the centre limbs assume the same magnetic polarity. When this occurs the armature 29 is repelled away from the solenoid to achieve closure of the valve. When one of the windings is deenergised the armature is attracted towards the solenoid and the valve is moved to the open position.

In both examples described it is a simple matter to change the solenoid in the event that a fault occurs in the winding or windings, without disturbing the valve.

This compares with known constructions of valve in which the armature is disposed on the remote side of the solenoid and is coupled to the moving component of the valve by means of a push rod which extends through an elongated opening formed in the core of the solenoid.

Claims

1. An electro-magnetically operable fluid control valve comprising a pair of valve components movable relative to each other to control the flow of fluid along a fluid flow path, one of said components being located in a supporting body, an armature carried by the other component, and a solenoid assembly contained within a casing which is adapted to be secured to the supporting bodyr the casing being located to the side of the armature remote from said other component whereby the solenoid assembly can be removed from the supporting body without disturbing the valve components.

2. A valve according to Claim 1, in which said solenoid assembly includes a core component and a first winding for magnetising said core component, the solenoid having a second winding for magnetising said armature whereby when the two windings are energised so that the presented faces of the armature and core component assume the same magnetic polarity, the armature will be urged away from the core component and when one only of the windings is energised the armature will be attracted towards the core component.

3. A valve according to Claim 1, in which said other component is slidable in the supporting body and defines a bore which forms part of said flow path, a seating defined in the bore, said one component being slidable in said bore and being shaped for cooperation with said seating, and means for limiting the movement of said one component towards the solenoid assembly whereby when the solenoid assembly is energised the two valve components will be moved relative to each other to prevent fluid flow along the flow path.

4. An electro-magnetically operable fluid control valve comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

5. An electro-magnetically operable fluid control valve comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.