GB2025576A

GB2025576A - Electromagnetically operable fluid control valves.

Info

Publication number: GB2025576A
Application number: GB7914616A
Authority: GB
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1978-07-12
Filing date: 1979-04-26
Publication date: 1980-01-23
Also published as: GB2025576B

Abstract

The valve includes a cup-shaped housing 10 having a port 12 in the base wall. A tubular valve element 14 is engageable with the base wall about the port under the action of a spring 21. A solenoid assembly 17 when operative lifts the valve element from the base wall to allow flow through the port. The valve element 14 has a location element 16 slidable within the bore therein to locate the valve element in the closed position thereof. <IMAGE>

Description

SPECIFICATION Electromagnetically operable fluid control valves This invention relates to electromagnetically oper able fluid control valves of the kind comprising a valve member which is urged into contact with a seating surface defined about an inlet port, by the traction of resilient means to prevent the flow of fluid through the port and a solenoid which when ener gised, lifts the valve member from the seating surface to permit fluid flow.

With such a valve any fluid forces acting on the valve member and tending to lift the valve member from the seating surface must be opposed by the force exerted by the resilient means. Since the fluid pressure may vary, the solenoid has to be designed so that it is capable of lifting the valve member from the seating surface even if the fluid pressure is low.

The force required to be exerted by the resilient means can be reduced if the area of the valve member exposed to the fluid pressure in the port is reduced. At the same time the power required to be developed by the solenoid can be reduced and it is to be expected that the resulting valve will be capable of operating much more quickly.

The object of the invention is to provide an electro-magnetically operable fluid control valve in a simple and convenient form.

According to the invention an electromagnetically operable fluid control valve comprises a non magnetic body portion of cup-shaped form, the base wall of said body portion defining a seating surface about a port formed therein, a tubular valve member having a peripheral flange formed thereon, resilient means acting into contact with said seating surface, a location element slidably accommodated within the bore of said valve member, and a solenoid assembly mounted within the open end of said body portion, said solenoid assembly defining a central pole piece which extends to adjacent the other end of said valve member and an annular pole piece which extends to adjacent said flange, a winding carried by said solenoid assembly and which when energised causes said central and said annular pole .pieces to assume opposite magnetic polarity, said valve member being formed from magnetisable material so that when said winding is energised the valve member is lifted away from said seating surface.

According to a further feature of the invention the end surface of said central pole piece adjacent the location element, is provided with a conical recess and said location element is formed as a ball whereby the ball is centralised in said recess and acts to centralise the valve member.

Two examples of electromagnetically operable fluid control valves in accordance with the invention will now be described with reference to the accom panying drawings the two figures of which show sectional side elevations through the valves.

With reference to Figure 1 of the drawings the valve comprises a cup shaped body portion 10 having a spigot portion 11 formed integrallythere- with. In the particular example the spigot portion is provided with a screw thread whereby the body portion can be secured within a mounting structure.

Formed in the base wall of the body portion 10 is an inlet port 12 which is connected by means of a passage 13 to an annular space defined in the supporting structure about the spigot portion of the valve.

Located within the cup-shaped body portion which is formed from non-magnetic material, is a valve member generally as indicated at 14 and which is of generallytubularform having a peripheral flange 15.

The valve member is formed from magnetisable material and its end surface can engage with the seating surface defined by the base wall of the cup-shaped portion 10 to form a fluid tight seal therewith. The material forming the body portion may be a plastics.

Located within the bore defined in the valve member is a location element in the form of a ball 16.

Located within the open end of the cup-shaped portion 10 is a solenoid assembly 17 which includes a central pole piece 18 and an annular pole piece 19, the two pole pieces being integrally formed. The end surface of the central pole piece 18 is provided with a conical recess 20 which provides a location for the ball 16 and mounted about the central pole piece is a coiled compression spring 21 which engages the flange 15 and biases the valve member towards the seating surface. A clearance exists between the other end of the valve member and the central pole piece 18 and a further clearance substantially identical with the first mentioned clearance, exists between the flange 15 and the annular pole piece 19.

The solenoid assembly also includes a winding 22, this being located within the annular space defined between the pole pieces. The pole pieces are formed from magnetisable material and the solenoid assembly is mounted upon or forms part of, an end closure member 23 which is held within the open end of the body portion 10 by means of a retaining cap 24 which in the particular example, is provided with a screw thread engaged with a screw thread formed on the body portion. The ends of the windings are connected to terminal blades 25.

The spigot portion 11 is provided with an axial passage 26 and this communicates by way of an obliquely formed passage portion 27 and a further axial passage 28, with the interior of the cup-shaped portion. Moreover, the flange 15 of the valve member is provided with apertures 29 which permit fluid flow between the opposite sides of the flange.

In use, fluid under pressure is supplied to the passage 13 and when the solenoid is de-energised, the valve member is held on the seating surface by the action of the resilient Means. When the winding is energised, the pole pieces assume opposite magnetic polarity and the valve member forms an armature between the pole pieces and moves towards the pole pieces to reduce the reluctance of the magnetic circuit. The end of the valve member is therefore moved away from the seating surface to permit flow of fluid through the port 12 into the cup-shaped portion and out through the passages 28, 27 and 26. The movement of the valve member is guided by the ball 16 which is urged into the recess 20 by the fluid pressure at the port 12, when the valve member is in the closed position.The valve member in the open position of the valve is substantially pressure balanced and in the closed position, presents a very small area against which the fluid pressure in the port 12 acts to generate a force which must be opposed by the spring 21. Thus the spring 21 can be a relatively weak spring and the solenoid does not need to be very powerful to overcome the force exerted by the spring even when there is a very low fluid pressure in the port 12. When the valve member is in the open position the ball will be pressure balanced since the conical recess 20 will not form a seal with the ball.

If the passage 26 is supplied with fluid under pressure, the ball 16 will in the closed position of the valve member, be urged towards the inlet port 12 and in orderto prevent the possibility of the ball acting as a closure member, the port is provided with a plurality of grooves about its periphery. In the open position of the valve member the ball is again pressure balanced.

In Figure 2 the spring is referenced 30 and it will be noted that in Figure 2 the flange which is referenced 31 is inclined outwardly towards the annular pole piece 19. This does enable the annular pole piece 19 to be approximately the same length as the central pole piece 18. Moreover, the spring 30 is of generally truncated conical configuration with the larger end ofthe spring seating against the winding 22.

In Figure 2 it will be noted that the annular pole piece 19 is provided with a longitudinal slit through which when the valve is open, fluid can flow to a circumferential channel defined about the base of the solenoid assembly. From this channel it flows into the passage 28.

Claims

1. An electromagnetically operable fluid control valve comprising a non-magnetic body portion of cup-shaped form, the base wall of said body portion defining a seating surface about a portformed therein, a tubular valve member having peripheral flange formed thereon, resilient means acting into contact with said seating surface, a location element slidably accommodated within the bore of said valve member, and a solenoid assembly mounted within the open end of said body portion, said solenoid assembly defining a central pole piece which extends to adjacent the other end of said valve member and annular pole piece which extends to adjacent said flange, a winding carried by said solenoid assembly and which when energised causes said central and said annular pole pieces to assume opposite magnetic polarity, said valve member being formed from magnetisable material so that when said winding is energised the valve member is lifted away from said seating surface.

2. A valve according to Claim 1 including a control recess formed in the end face of said central pole piece, said location member being in the form of a ball which is centralised by said recess and which acts to centralise the valve member.

3. A valve according to Claim 2 in which the base wall of the body portion about said port is grooved to prevent said ball obturating said port.

4. Avalve according to Claim 1 in which said body portion is formed from plastics material.

5. A valve according to Claim 1 including flow passages defined in said flange.

6. A valve according to Claim 1 including a closure member for closing the open end of said body portion and including a passage formed in,the body portion and communicating with the interior thereof.

7. Avalve according to Claim 6 including a retaining cap engaged with the body portion for retaining said closure member within the body portion.

8. Avalve according to Claim 6 in which said solenoid assembly is mounted upon said closure member.

9. A valve according to Claim 8 including terminals mounted on said closure member, said terminals being connected to the ends of said winding.

10. An electromagnetically operable fluid control valve comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

11. An electromagnetically operable fluid control valve comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.