GB2329231A - Solenoid valve - Google Patents

Abstract

A solenoid valve assembly, for controlling the connection between an inlet (18), outlets (15,16) and branch passages (20A,20B) comprises four identical solenoid valves. Each valve comprises a coil (2,3,4,5) and an armature (22,32,42,52) slidably mounted in a cylinder defined by the coil former. Each armature carries a seal (12) which is normally biased into engagement with an associated seat by springs (8,9) acting between a pair of armatures. Each armature has a through bore (23,33,43,53) which connects a chamber (19) which surrounds the outer end of the armature to a common zone of the cylinder (6,7) in which the respective armatures are mounted. The chamber (19) associated with armature (22) is connected to branch passage (20A) and the chamber (19) associated with armature (42) is connected to branch passage (20B). By selectively energising the solenoid valves each branch passage can be connected either to the inlet (18) or a respective outlet (15,16). The passage from the branch passages (20A,20B) to the respective outlets (15,16) is via the through bores provided in the respective armatures.

Description

SOLENOID VALVE This invention relates to a solenoid valve, and in the preferred embodiment provides a solenoid valve particularly suitable for controlling the connection of an inflatable bladder to a source of inflation fluid and to a reservoir.

It is to be understood, however, that the solenoid valve of the present invention may be used for a wide range of applications and its use is not limited to the preferred application of controlling the connection of a bladder to a source of inflation fluid and to a reservoir. In a particularly preferred embodiment of the invention the solenoid valve is able to control the connection of a multiplicity of bladders to a single source of inflation fluid or to reservoir with a wide range of possible combinations of connection. However, it is again to be understood that the invention is not limited to applications in which there are a multiplicity of connections, and in its simplest form the invention may be applicable to the control of the connection of three fluid ports to each other. In this broadest context, the invention has a wide range of uses.

The particularly preferred embodiment of the present invention is used to control the connection between at least two inflatable bladders and a common source of inflation air on the one hand, and atmosphere on the other hand. The bladders may, for example, form part of a seating installation and may, for example, comprise lumbar support bladders located respectively in the drivers seat and front passenger seat or rear seat(s)of a motor vehicle. In an alternative application, both bladders may be located within the same seat of a motor vehicle. Alternatively, the bladders may be located within a chair structure.

The use of inflatable bladders to control the lumbar support of motor vehicle seats is known. In general, in order to increase the degree of lumbar support air must be pumped into a bladder, and in order to reduce the amount of lumbar support, air must be allowed to bleed from the bladder. The supply of air to and bleeding of air from a bladder may be controlled by a manually operable pump and vent valve. However, it is preferable to provide an electric pump for the purposing of supplying air and to provide an electrically controlled vent for the purposes of bleeding air from the bladder. If an installation comprises a multiplicity of bladders, it is preferable to provide a single pump which can selectively be connected to the bladders for inflation purposes, and to provide respective solenoid valves to allow the bladders to be individually bled. The preferred embodiment of the present invention provides a solenoid valve assembly which allows selective connection of a multiplicity of bladders to a single source of inflation air, and the selective connection of each of the bladders to atmosphere to allow air within the bladder to be bled. The ability of the preferred embodiment of the invention to allow simultaneous inflation of one bladder and deflation of another bladder is a major benefit in operating efficiency of inflatable bladder seat systems.

According to one aspect of the present invention a solenoid valve comprises an inlet for connection to a source of inflation fluid, an outlet for connection to a reservoir of inflation fluid; a branch connection; a first solenoid valve for controlling communication between the inlet and the branch connection; and a second solenoid valve for controlling connection between the branch connection and the outlet, the flow path from the branch connection to one of the inlet or the outlet being in part defined by a passage which extends through the movable members of the solenoid valves.

In the preferred embodiment of the invention the solenoid valves are substantially identical and each comprises a coil and an armature slidably mounted in a cylindrical passage passing axially through the coil. The coils are arranged coaxially so that the cylindrical passages form a common cylinder in which the two armatures are mounted. The armatures are biased away from each other by a common spring which is located within the cylinder.

Each armature comprises a through passage which connects the portion of the common cylinder located between the armatures to the exterior of the outer ends of the armatures.

Accordingly, a flow path is defined from the exterior of the outer end of one armature, through that armature, through the portion of the cylinder between the armatures, and through the passage in the other armature to the exterior of the outer end of the other armature. The outer end of each armature is preferably surrounded by a chamber. One such chamber is connected, upon movement of its associated armature in response to energisation of the associated coil, to the inlet. The other chamber is connected, upon movement of its associated armature in response to energisation of the associated coil, to the outlet. One of the chambers is connected to the branch passage. It will be appreciated that, because the chambers are permanently connected by the passages in the armature and the portion of the cylinder located between the armatures, the branch passage may be selectively connected to the inlet or to the outlet by actuation of the appropriate coil.

Preferably, the outer ends of each armature carry a seal which is normally biased into sealing contact with a seat by the spring which biases the armatures away from each other. Accordingly, upon energisation of one of the coils the associated armature will be drawn into the coil to move the seal clear of the seat and allow the chamber associated with that armature to be connected to the inlet or outlet according to which of the coils is energised. Preferably, the coils, armatures and seals are identical so as to reduce the number of parts required to assemble the valve.

Preferably, the cylinder, at the interface of the coils, is sealed to prevent fluid loss at this point. Preferably, sealing is effected by a connecting piece which extends partly into the central passage of each coil and is sealed against the wall of the passage by suitable sealing means.

Preferably, the connecting piece provides stops for limiting the axially inward movement of the armatures.

In a particularly preferred embodiment of the invention intended to control the connection of a pair of bladders to a common source of inflation fluid, and to atmosphere, four coil/armature sets are provided arranged in two back-to-back pairs. The two inlets are connected to a common gallery which itself is provided with an inlet for inflation fluid.

In many applications the controlled fluid is air and accordingly the or each outlet may comprise a vent to atmosphere.

In cases where more than two fluid devices are to be controlled, a pair of coil and armature assemblies, mounted back to back, are provided associated with each fluid device. If the fluid devices are to be connected to a common inlet, all the inlets to the armature/coil pairs are connected to a common gallery.

The above and further features and advantages of the invention will become clear from the following description of a preferred embodiment thereof given by way of example only, reference being had to the accompanying drawings wherein: Figure 1 shows a cross-section of a preferred embodiment of the invention intended to control the connection between a pair of inflatable bladders and a single source of inflation fluid on the one hand and atmosphere on the other hand; and Figure 2 is a cross-section on the line II-II of Figure 1 Referring firstly to Figure 1, the illustrated solenoid valve 1 comprises four coils 2,3,4,5 wound on respective formers 21,31,41 and 51 each of which defines a substantially cylindrical passage in which a respective armature 22,32,42,52 is slidably mounted. The coil/armature assemblies are arranged in two back-to-back pairs, the coil 2 being arranged back-to-back with the coil 3 and the coil 4 being arranged back-to-back with the coil 5. The coils of each pair are coaxial so that the formers 21 and 31 form a cylinder 6 in which the armatures 22 and 32 are slidably mounted, and the formers 41 and 51 form a cylinder 7 in which the armatures 42 and 52 are slidably mounted. The armatures 22 and 32 are biased apart by a common spring 8 and the armatures 42 and 52 are biased apart by a common spring 9. The cylinders 6,7 house respective connectors 10,11 which are sealed to the interior surfaces of the coil formers by O-ring seals to prevent loss of fluid from the cylinders 6,7 at the interface between the coils. The connectors 10,11 also provide stops which limit the axially inward movement of the armatures upon energisation of their associated coils.

Each armature carries, at the outer end thereof, a seal 12 which, when the coils are not energised, is biased into engagement with a valve seat by the associated armature spring. The various seats define a first inlet 13, a second inlet 14, a first outlet 15 and a second outlet 16. The inlets 13,14 are connected to a common gallery 17 which, in use, is connected to a supply of inflation fluid via a nipple 18.

The outer end of each armature is surrounded by a chamber 19. The chamber 19 associated with the armature 22 is connected to a first branch passage 20A and the chamber 19 associated with the armature 42 is connected to a second branch passage 20B. In use, the branch passages 20A,20B are connected to respective fluid appliances, for example inflatable bladders of an automobile seating installation.

Each armature is formed with a through passage 23,33,43,53. The respective through passages connect the chamber 19 of each respective armature to the central portion of the cylinder 6,7 associated with that armature.

Thus, a permanent passage is established between the chamber 19 associated with the armature 22 and the chamber 19 associated with the armature 32. Similarly, a permanent passage is established between the chamber 19 associated with the armature 42 and the chamber 19 associated with the armature 52.

In use, the solenoid valve will normally be deenergised with the result that the seals 12 will normally be biased into engagement with their associated seats so that the branch passages 20A,20B are both isolated from the gallery 17 and from atmosphere. If it is wished to add air to the device connected to the branch passage 20B the coil 4 is energised thereby drawing the armature 42 inwardly and lifting the associated seal 12 from its corresponding seat.

Air may accordingly flow from the inlet gallery 17 via the inlet 14 and the chamber 19 associated with the armature 42 into the branch passage 20B. The addition of air is ceased by de-energising the coil 4 where upon the armature 42 will return to its rest position under the influence of the spring 9. If it is desired to allow air to bleed from the appliance connected to the branch passage 20B the coil 5 is energised thereby drawing the armature 52 inwardly to lift the associated seal 12 from its adjacent seat. Air may then bleed from the appliance through branch passage 20B, the chamber 19 associated with the armature 42, the through passage 43 of the armature 42, the central portion of the cylinder 7, the passage 53 of the armature 52, the chamber 19 associated with the armature 52 and the outlet 16 to atmosphere.

The connection of the branch passage 20 to the gallery 17 and to the outlet 15 may similarly be controlled by energisation of the coils 2,3.

The above described solenoid valve provides the necessary control of the various connections to permit selective inflation and deflation of the devices attached to the branch passages 20A,20B. The design is compact and makes use of a relatively small number of different components. It is particularly suited to automobile applications for controlling the inflation and deflation of bladders incorporated within automobile seats.

Claims (14)

1. A solenoid valve assembly comprising: an inlet for connection to a source of inflation fluid; an outlet for connection to a reservoir of inflation fluid; a branch connection; a first solenoid valve for controlling communication between the inlet and the branch connection; and a second solenoid valve for controlling connection between the branch connection and the outlet, the flow path from the branch connection to one of the inlet or the outlet being in part defined by a passage which extends through the movable members of the solenoid valves.

2. A solenoid valve assembly according to claim 1 wherein: the solenoid valves each comprises a coil and an armature slidably mounted in a cylindrical passage passing axially through the coil.

3. A solenoid valve assembly according to claim 2 wherein the coils are arranged coaxially so that the cylindrical passages form a common cylinder in which the two armatures are mounted.

4. A solenoid valve assembly according to claim 3 wherein the armatures are biased away from each other by a common spring which is located within the cylinder.

5. A solenoid valve assembly according to claim3 or claim 4 wherein each armature comprises a through passage which connects the portion of the common cylinder located between the armatures to the exterior of the outer ends of the armatures.

6. A solenoid valve assembly according to any of claims 2 to 5 wherein the outer end of each armature is surrounded by a chamber, one chamber being connected, upon movement of its associated armature in response to energisation of the associated coil, to the inlet, and the other chamber being connected, upon movement of its associated armature in response to energisation of the associated coil, to the outlet.

7. A solenoid valve assembly according to claim 6 wherein one of the chambers is permanently connected to the branch passage.

8. A solenoid valve assembly according to any of claims 4 to 7 wherein the outer ends of each armature carry a seal which is normally biased into sealing contact with a seat by the spring which biases the armatures away from each other.

9. A solenoid valve assembly according to any of claims 3 to 8 wherein the cylinder, at the interface of the coils, is sealed to prevent fluid loss at this point.

10. A solenoid valve assembly according to claim 9 wherein sealing is effected by a connecting piece which extends partly into the central passage of each coil and is sealed against the wall of the passage by suitable sealing means.

11. A solenoid valve assembly according to claim 10 wherein the connecting piece provides stops for limiting the axially inward movement of the armatures.

12. A solenoid valve assembly according to any preceding claim for controlling the connection of a pair of bladders to a common source of inflation fluid, and to atmosphere, comprising four coil/armature sets arranged in two back-toback pairs with the two inlets connected to a common gallery which itself is provided with an inlet for inflation fluid.

13. A solenoid valve assembly according to any preceding claim wherein the solenoid valves are identical to each other.

14. A solenoid valve, substantially as hereinbefore described with reference to the accompanying drawings.