US2866476A

US2866476A - Electro-magnetically operated control valves

Info

Publication number: US2866476A
Application number: US346235A
Authority: US
Inventors: Orloff George
Original assignee: British Messier Ltd
Current assignee: British Messier Ltd
Priority date: 1952-04-03
Filing date: 1953-04-01
Publication date: 1958-12-30
Anticipated expiration: 1975-12-30

Description

Dec. 30, 1958 G. ORLOFF 2,366,476

ELECTROMAGNETICALLY OPERATED CONTROL VALVES Filed April 1, 1953 lhv n f I" United States Patent i ELECTRO-MAGNETICALLY OPERATED CONTROL VALVES George Orlotf, Cheltenham, England, assignor to British Messier Limited, Gloucester, England, a British com- P y Application April 1, 1953, Serial No. 346,235

Claims priority, application Great Britain April 3, 1952 9 Claims. (Cl. 137-620) This invention comprises improvements in or relating to electromagnetically operated control valves, and it has for its object to provide an improved type of electrohydraulic valve for use in a circuit where a small electric controll current only is available.

According to the present invention an electromagnetic control valve for a fluid-pressure circuit comprises in combination a movable valve-member, fluid-pressure actuated means for moving the valve-member in one direction, fluid-pressure actuated means for moving it in the reverse direction, a fluid-supply passage for fluid under pressure to each of the two fluid-pressure actuated means and a fluid exit therefrom, means for throttling each of the said fluid-supply passages and each of said exits, and electromagnetically controlled means for varying the relative degree of such throttling for the two fluid-pressure actuated means to cause them to move the valve.

Preferably, the valve is caused by its movement to modify the relative throttling of the two fluid-pressure actuated means in such manner as to restore their balance and limit the valve movement.

In one construction in accordance with the invention the valve-member is a piston valve working in a valvebore and the fluid-pressure actuated means for moving it are actuatingchambers at the ends of the valve-bore and piston-faces on the piston valve, working in said chamber. If the piston faces overlapthe exits from the actuating chambers when the valve is moved the eiiect is that the relative throttling of the two exits is modified as above described so as to limit the valve movement.

The electromagnetically controlled means of varying the relative throttling may comprise an electromagnet having a polarized armature which carries an obturating member movable between jets on the fluid-exits so that on movement in one direction it increases obturation of one jet and in the other direction increases obturation of the other jet.

The following is a description by way of example of one construction in accordance with the invention:

The accompanying drawing shows the construction diagrammatically.

In the following description the electromagnetically controlled valve is assumed to be intended for controlling a hydraulic jack which comprises a piston 11 working in a cylinder 12; a piston rod 13 projects from the cylinder at one end and constitutes an operating member by which the jack acts on parts (such for example as a rudder flap) to be moved; pressure is constantly applied by pipe 15 at the end 14 of the cylinder through which the piston rod 13 projects; if an equal pressure supply is applied through pipe 16 at the other end 17 of the cylinder the piston rod will be urged outwards because the area of the piston is less on the piston rod Side by the amount of the cross sectional area of the rod; if pressure on the end 17 is relieved, the rod 13 is drawn inwards by the constantly applied pressure. Thus only the pressure at one end of the jack-cylinder 12 need be controlled. 7

The control is efiected by a valve box 18 containing a 2,866,476 Patented Dec. 30, 1958 cylindrical valve bore 19 in which operates a piston valve 20. The piston valve has three pistons upon it separated by two

annular grooves

21, 22 and the valve bore has three

ports

23, 24, 25 controlled by the piston valve. The central port 24 is connected to the jack which is to be controlled by pipe 16 and in the central position of the valve is obturated by the centre piston thereof. The other two ports are, in this position, in line with the grooves in the valve body. One of them, 23, is connected by a passage 26 to a pipe connection 27 taken from the pressure supply; the other is connected by ano.her assage 28 to an exhaust chamber 42 leading to an exhaust tank pipe 29. Thus if the valve member is moved in one direction it will connect the central port 24 to the pressure and if it is moved in the other direction it will connect it to exhaust, in the way which is usual with piston valves. The ends of the valve constitute piston faces and the ends of the valve bore 19 constitute actuating chambers 32, 33 for fluid-pressure actuation of the valve. By means of

passages

30, 31 in the valve body each of the actuating chambers 32, 33 is connected to the pressure supply passage 26 and the inlet to each chamber from the pressure supply is provided with a restriction (34, 35) so that on flow of pressure fluid into either chamber there is a fall of pressure. In the side wall of the valve bore there are two exit passages 36, 37 also provided with restrictions 38, 39 and the pass-ages 36, 37 lead to two opposed control-

jets

40, 41 which open from the passages into the exhaust chamber 42 connected to the aforesaid pipe 29 leading to exhaust. Thus, there is a constant flow through the two actuating chambers 32, 33 from the pressure supply 27 through the restrictions 34, 35 at the entrances to the chambers, then through the restrictions 38, 39 at the exits and the

jets

40, 41 to exhaust and if the restrictions and the jets are equal on both sides the pressure on the piston faces on the valve member 20 will be equal and it will not tend to move.

The exits 38, 39 from the valve bore 19 are made in such positions that when the valve member 20 is central its piston faces on its ends will lie at the edges of the exit restrictions 38, 39. Any move in one direction by the valve member will therefore reduce one restriction (38 or 39) while leaving the other open, while movement in the other direction will reduce the other restriction. The effect is that the pressure tends to be increased in the actuating chamber towards which the valve member moves, and this has the effect of centering the valve member and causing it normally to close the port 24 leading to the jack 12 and thereby to lock the jack in whatever position it may be occupying at the moment when the central port of the valve member is closed.

In the exhaust chamber 42 of the valve body there is located a polarized electromagnet 45. This comprises a rectangular permanent magnet 46 with pole faces close together and facing one another. A movable armature 47 is pivoted to the permanent magnet in the centre of one side opposite to the opposed pole faces and it extends across the rectangular space within the permanent magnet and through the opening between the, pole faces. This armature is surrounded with the magnet winding 45 and if the current in the winding is in one direction the armature 47 will be attracted to one of the pole faces whereas if it is in the other direction it will be attracted to the ply of a small electric current to the winding in accordance with the direction of the desired movement. k

The armature 47'is extended beyond the pole faces to a point where it lies between the opposed jets on the exits from the valve chamber. Here it carries a metal ball 50 which is concentric with the exits of the jets. 1f the magnet winding is energised in one direction the ball will tend to move toward one jet and obturate it more or less while if the current in the magnet winding is reverse-d the ball will move in the opposite direction and obturate the other jet. If the magnet winding is not energised the ball will remain central. ln the first case the pressure in one of the actuating chambers of the valve will be caused to rise and the valve will move over, thereby opening the central port 24 to, say, the pressure supply and will actuate the jack 12. In so doing the piston face of the valve 20 at the end remote from the exit which has been obturated by the ball on the polarized magnet armature will be closed and the pressure in the ctuating chamber (32 or 33 as the case may be) which is thus closed will be caused to rise until the valve movement ceases. The movement of the jack will, however, continue as long as the current is maintained in the magnet winding, or until the jack reaches the end of its stroke, as the case may be. When the current is cut oil from the magnet winding the ball member 50 on the polarized armature will automatically move away from the jet which it has been obturating and the pressure in the corresponding actuating chamber of the valve will fall. The valve 20 will therefore move back until it has centralized itself and the jack is locked in the position to which it has been moved. If the current in the winding is in the reverse direction to the case first supposed the valve member will be moved in the opposite direction through obturation of the other jet by the ball member 50 and, in the case supposed, the jack will be connected to exhaust. It will move correspondingly as long as the current is kept on in the magnet, or until it reaches the end of its stroke. As soon as current is cut off the jack will be locked owing to the centering of the valve member 20, as before.

It will be observed that a small movement only of the polarized armature is required in one direction or the other to bring about complete actuation of the jack and thus the device is readily controlled by small currents, while the jack is locked as soon as current is cut ofl. The force actuating the jack is independent of the force actuating the polarized armature and thus small control currents can be effectively employed.

I claim:

1. An electromagnetic control-valve for a fluid pressure ciricuit, comprising in combination a movable valve member, fluid-pressure-actuated means for moving it in one direction and for restoring it when moved in the reverse direction, oppositely-acting fluid-pressure-actuated means for moving it in the reverse direction and for restoring it when moved in the first direction, a fluid supply passage for fluid under pressure to each of the two fluid pressure-actuated means, a fluid outlet port from each of the two fluid-pressure-actuated means and a fluid exit from each of said fluid outlet ports, means for throttling each of said fluid supply passages and each of said fluid exits, means for controlling the area of said exits in response to movement of said valve member and electromagnetically controlled means for varying the relation between the amount of throttling of the fluid supply passages and the amount of throttling of the exits of each of the fiuid-pressure-actuated means to cause said fluidpressure-actuated means to move the valve member, and wherein the valve member controls the areas of said exits for the two fluid-pressure-actuated means whereby when the valve moves in either direction the fluid pressure in the fluid-pressure-actuated means tending to restore the valve builds up in comparison to that in the fluidpressure actuated means moving the valve.

2. An electromagnetic control-valve as claimed in claim 1 wherein the valve-member is a piston-valve working in-a valve-bore and the fluid-pressure actuated means for moving it are actuating-chambersv at the ends of the valvef: bore and piston-faces on the piston valve, working in said chambers.

3. An electromagnetic control-valve as claimed in claim 2 wherein the piston faces are so disposed in relation to the exits from the actuating chambers that when the valve is moved in either direction the piston face for returning it overlaps and partly closes the exit from its chamber, and vice versa.

4. An electromagnetic control-valve as claimed in claim 3, wherein the electromagnetically-controlled means for ,1 1-,: relative throttling comprises an electromagnet, a POlZti'lZtid armature therefor, an obturating member on said armature, and jets on the fluid-exits, located one on each side of said obturating member, so that on moveent of the armature in one direction, it increases obturation of one jet and in the other direction increases obturation of the other jet.

5. 'An electromagnetic control-valve as claimed in claim 1, wherein the electromagnetically-controlled means for varying the relative throttling comprises an electromagnet, a polarized armature therefor, an obturating member on said armature, and jets on the fluid-exits located one on each side of said obturating member, so that on movement of the armature in one direction, it increases obturation of one jet and in the other direction increases obturation of the other jet.

6. An electromagnetic control-valve for a fluid-pressure circuit, comprising, in combination, a movable valve member, fluid-pressure-actuated means for moving it in one direction, and for restoring it when moved in the reverse direction, oppositely-acting fluid-pressure-actuated means for moving it in the reverse direction, and for restoring it when moved in the first direction, a fluid inlet port to each fluid-pressure-actuated means, and a fluid outlet port from each fiuid-pressure-actuated means, each said fluid outlet port being positioned with respect to the valve member so as to be at least partially covered on movement in the appropriate direction by the valve member, a fluid supply passage to each of the fluid inlet ports and a fluid exit passage from each of the fluid outlet ports, movable throttling means operatively associated with said fluid exit passages for varying the relative pressure in said fluid-pressure-actuated means and electromagnetically controlled means for moving said throttling means to cause the fluid-pressure-actuated means to move the valve member, and wherein the valve member controls said outlet ports for the two fluid-pressure-actuated means whereby when the valve moves in either direction the fluid pressure in the fluid-pressure-actuated means tending to restore the valve builds up in comparison to that in the fiuid-pressure-actuated means moving the valve.

7. An electromagnetic control-valve for a fluid-pressure circuit, comprising in combination a movable valve member, fluid-pressureactuated means for moving it in one direction and for restoring it when moved in the reverse direction, oppositely-acting fluid-pressure-actuated means for moving it in the reverse direction and for restoring it when moved in the first direction, a permanently open fixed area fluid-supply passage for fluid under pressure to each of the two fluid-pressure-actuated means, a variablearea fluid outlet port from each of said fluid-pressureactuated means and a fluid exit from said fluid outlet ports, means for controlling the area of said outlet ports in response to movement of said valve members, movable means for throttling each of said fluid exits, but not the fluid-supply passages, to a varying extent, and electromagnetically controlled means for moving said throttling means to vary the relation between the pressures in the two fiuid-pressure-actuated means and thereby cause them to move the valve, and wherein said variable-area fluid outlet ports are controlled by said valve member whereby on movement of said valve member, the area of the outlet port of the fluid-pressure-actuated means tending to restore the valve is reduced as compared with the area of the other outlet port.

8. An electromagnetic control-valve according to claim 7, wherein fixed area throttling means are provided in each of the fluid supply passages.

9. An electromagnetic control-valve for a fluid-pressure circuit, comprising in combination a movable valve-member, fluid-pressure-actuated means for moving it in one direction and for restoring it when moved in the reverse direction, oppositely acting fluid-pressure-actuated means for moving it in the reverse direction and for restoring it when moved in the first direction, a fluid supply passage for fluid under pressure to each of the two fluid-pressureactuated means and a fluid exit therefrom, means for throttling each of said fluid supply passages and each of said exits, and electromagnetically controlled means for varying the relation between the amount of throttling of the fluid supply passages and the amount of throttling of the exits of each of the fluid-pressure-actuated means to cause them to move the valve member, and wherein 20 the valve member overlaps ports leading to said exits whereby its movement modifies the relation between the amount of throttling of the two fluid supply passages and the exits in such manner as to restore the balance between the two fluid-pressure-actuated means and limit the valve movement.

References Cited in the file of this patent UNITED STATES PATENTS