US3662784A

US3662784A - Torque motor controlled fluid valve

Info

Publication number: US3662784A
Authority: US
Inventors: John M Perhach
Original assignee: GLAR BAN CORP
Current assignee: GLAR BAN CORP
Priority date: 1970-11-02
Filing date: 1970-11-02
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16

Abstract

Movement of the armature of a torque motor controls the position of the spool valve element of a four-way valve. A valve member carried by the armature lies between a pair of nozzles leading from the pressure port of the four-way valve and balanced springs normally center the spool valve element. Movement of the armature moves the valve carried thereby closer to one of the nozzles and farther from the other and this causes unbalanced dynamic fluid pressure in the passages leading to the nozzles which pressures are applied to opposite ends of the spool valve and thus moves the spool valve in one direction or the other from its neutral central position. Bellows members extend from opposite faces of the valve carried by the armature of the torque motor to enclose the region in which the nozzles discharge thus effectively isolating the nozzle discharge fluids from the torque motor itself and the ambient atmosphere to prevent egress of the fluid being controlled and to prevent contamination or dilution of the fluid by the ambient atmosphere.

Description

United States Patent Perhach 51 May 16, 1972 I 22 Filed:

[54] TORQUE MOTOR CONTROLLED FLUID VALVE [72] Inventor:

[73] Assignee:

[52] US. Cl ..l37/625.62 [51] Int. Cl ..Fl5f 5/00, Fl6k 11/07 [58] Field of Search 91/51 461; 137/82, 85, 625.62,

[56] References Cited UNITED STATES PATENTS 2,747,61 l 5/1956 Hewitt ..l36/625.69

Primary Examiner-Henry T. Klinksiek Attorney-Christel & Bean ABS I'RACT Movement of the armature of a torque motor controls the position of the spool valve element of a four-way valve. A valve member carried by the armature lies between a pair of nozzles leading from the pressure port of the four-way valve and balanced springs normally centerthe spool valve element. Movement of the annature moves the valve carried thereby closer to one of the nozzles and farther from the other and this causes unbalanced dynamic fluid pressure in the passages leading to the nozzles which pressures are applied to opposite ends of the spool valveand thus moves the spool valve in one direction or the other from its neutral central position. Bellows members extend from opposite faces of the valve carried by the armature of the torque motor to enclose the region in which the nozzles discharge thus effectively isolating the nozzle discharge fluids from the torque motor itself and the ambient atmosphere to prevent egress of the fluid being controlled and to prevent contamination or dilution of the fluid by the ambient atmosphere.

7 Claims, 4 Drawing Figures Patented May 16, 1972 3,662,784

2 Sheets-Sheet l ZZZ INVENT'OR JOHN M PEQH/q CH BY WQ M ATTOQNEYS Patented May 16, 1972 2 Sheets-Sheet 2 INVENTOQ JOHN M. PEQHACH gmv dw w A TTOQA/EVS TORQUE MOTOR CONTROLLED FLUID VALVE BACKGROUND OF THE INVENTION It is known in the art to control the position of the spool valve or similar valve member of a four-way valve by means of an electric torque motor. In these prior art arrangements the movable armature of the torque motor carries a member which normally lies midway between a pair of fluid nozzles. Fluid issuing from the noules comes from the fluid pressure source of the four-way valve and when the member carried by the torque motor armature is moved from mid position closer to one nozzle and farther from the other, it creates an imbalance of dynamic fluid pressure in the passages leading to the nozzles and this imbalance is applied to the opposite ends of the spool valve member to bias the same in one direction or another from its normally centered position.

In such prior art devices the fluid issuing from the nozzles may escape to the atmosphere with consequent loss of fluid and possibly harmful effect on the adjacent torque motor, or the atmosphere itself. Conversely, the fluid in the system may be diluted or contaminated by the ambient atmosphere.

SUMMARY OF THE INVENTION The present invention provides a torque motor controlled four-way valve system wherein the aforesaid nozzles are fully and. hermetically enclosed so that all fluid issuing therefrom remains within the system and is returned to the return passage of the four-way valve mechanism or to a suitable reservoir. The fluid in the system is thus efi'ectively prevented from contaminating its ambience or from being contaminated thereby.

A further feature of the present invention comprises the construction of the four-way spool valve element itself. In accordance with the present invention the spool members are separately fabricated and then secured to a spool shaft by brazing or the like. Prior to mounting the spools on the shaft slots are milled across the ends of the spools and the bottoms of these slots cooperate with the passage openings leading to the spool to define the degree of opening of the valve. The unslotted portions of the spool thus remain in bearing contact with the bore which receives the spool valve when the valve is moved to open condition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectional view of one form of the four-way valve and control apparatus of the present invention;

FIG. 2 is a topplan view thereof with portions broken away for added illustration;

FIG. 3 is a cross-sectional view on the line III-Ill of FIG. 1; and

FIG. 4 is a cross-sectional view on the line IV-IV of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The valve and control assembly illustrated in the drawings comprises a four-way valve which is positionally controlled by fluid pressure which in turn, is controlled by an electric torque motor. The torque motor acts to connect a pressure source with one or the other of a pair of output or cylinder ports leading from the control valve. The control is proportional.

Referring particularly to FIG. 1, a valve body is designated and has a valve receiving bore 11 extending therethrough. A spool valve is designated generally by the numeral 12 and comprises a supporting shaft 13 having

valve collars

14, 15 and 16 fixed thereto. The collar 15 normally blocks a pressure inlet passage 17 and is movable in opposite directions to connect the same with either of a pair of

cylinder ports

18 and 19 and the collars 14 and 16 control communication between the

cylinder passages

18 and 19 and

return fluid passages

20 and 21, respectively, leading from valve body 10. The

return fluid passages

20 and 21 are connected by a longitudinal passage 22 shown in FIG. 3.

The novel features of the control valve of the present invention are, first, means whereby the torque motor acts to move a control valve member which acts against a pair of bypass fluid outlet members or nozzles leading from the pressure supply passage 17. Bellows members extending in opposite directions from the control valve member isolate the control valve member and the nozzles from the surrounding area including the torque motor.

The second point of novelty resides in the specific construction of the collar valve per se wherein the spool members are fabricated in the form of sleeves which have their radial end faces milled to provide radially extending fluid metering passages which extend completely across such end faces in a radial direction, the sleeves then being fixed to a supporting shaft by brazing or in any other desired manner. This greatly simplified fabrication of the spool valves.

FIG. 4 shows the left end of collar 15 as viewed in FIG. 1 and the two milled slots therein are designated 22. This leaves projections 23 which remain in bearing contact with bore 11 when the valve collar is shifted to the right to establish fluid communication between pressure port 17 and cylinder port 18 by way of slots 22. The proximal ends of collars 14 and 16 are similarly slotted.

The

ports

17, 20 and 21 are cast into valve body 10 and to insure precision lines of demarcation as between these ports and the slots 22 of the valve collars grooves 60, 61 and 62 are machined into

ports

17, 20 and 21, respectively, so that precision communication is provided as defined, for example, in collar 15 by the bottoms of slots 22 and the bottoms of the grooves 60 of pressure port 17.

In FIG. 1 the numeral 25 designates one form of conventional torque motor having an armature 26 which is fixed to the periphery of a discoidal valve plate 27. Valve plate 27 lies between the discharge ends of a pair of nozzles 28 and 29 and these nozzles have permanent fluid pressure connection with pressure source 17 in the following manner.

A fluid pressure passage 30 extends in opposite directions from pressure supply passage 17 to the outer ends of valve body 10 and thus communicates fluid pressure to spaces 31 and 32 between the outer ends ofvalve body 10 and a pair of

closure members

33 and 34 which are spaced from the outer ends of valve body 10 by 0 rings 35 and 36, or other suitable packing rings, thus establishing the end spaces 31 and 32.

Fluid passages 40 and 41 lead inwardly from the end spaces 31 and 32, respectively, and thence upwardly to communicate with passages 43 and 44 in a block 45 which supports nozzle members 28 and 29, thus establishing fluid communication to the interiors of the nozzles 28 and 29. The nozzles 28 and 29 are threaded into block 45 for screw adjustment in an axial direction. A pair of restricted orifice members 47 and 48 (see FIG. 2) are provided in opposite ends of passage 30 to establish a pressure drop between the pressure source 17 and the passages leading to nozzles 28 and 29.

Spool valve 12 is normally centered by balancing

coil springs

50 and 51 which bear against the outer ends of the spool assembly 12. Generally cylindrical bellows members 53 and 54 connect between opposite faces of valve plate 27 and block 45 to isolate the valve and nozzle area of the assembly from the torque motor area. This is an important feature of the present invention and is highly useful whether the operating medium which flows from the nozzles 28 and 29 be hydraulic or pneumatic. The operating medium is thus prevented from escaping to the torque motor housing and the operating medium is protected from external contamination.

In the present embodiment, valve 27 is perforated as at 60 to establish equal pressure conditions at opposite sides thereof within the bellows members 53 and 54, and this interior space is connected for free return of fluid to return passage 21 by way of a passage 56 in block 45 and valve body 10 from the interior of bellows member 54 to passage 21. In the alternative, a duplicate return passage may be provided from the interior of bellows member 53 to return passage 20, as indicated in dot and dash lines at 61 in FIG. 1, in which case valve 27 need not be perforated, since in that case the space on both sides thereof is freely open to the return side of the system.

When valve plate 27 is in a neutral position midway between the opposed nozzles 28 and 29, equal amounts of fluid will be bypassed from fluid pressure source 17 through passage 30, spaces 31 and 32, passages 40 and 41, passages 43 and 44, and the nozzles 28 and 29. The spool valve 12 will thus be subjected to balanced fluid pressures at its opposite ends and will remain centered by

springs

50 and 51. In each instance the flow from the nozzles will be at a reduced dynamic fluid pressure with respect to the pressure at the source 17 by reason of the presence of the orifice members 47 and 48 in the opposite ends of passage 30.

If torque motor 25 operates to pivot its armature 26 in a counterclockwise direction, as viewed in FIG. 1, thus moving valve plate 27 closer to nozzle 29, more fluid will flow from nozzle 28 than from nozzle 29 and the pressure in space 31 will decrease and the pressure in space 32 will increase. This differential pressure will move spool valve 12 to the left as viewed in FIG. 1 until the relative forces of

springs

50 and 51 and the bemoulli force due to fluid flow balances the differential pressure.

This moves collar 15 to the left to connect fluid pressure from source 17 to cylinder port 19 and the corresponding movement of collar 14 to the left opens return passage 20 to the interior of bore 11 to the right of collar 14, thus establishing return connection with respect to cylinder passage 18.

A preferred embodiment of the present invention has been described and illustrated herein to illustrate the principles of the invention but it is to be understood that numerous modifications may be made without departing from the broad spirit and scope of the invention.

I claim:

1. Valve means including a housing, a fluid pressure source and a valve member slidable in opposite directions from a neutral medial position to establish pressure connection in opposite directions, means normally centering said valve member, control means comprising a torque motor and a valve plate carried thereby, a pair of fluid nozzles connecting from said pressure source and directed toward opposite sides of said valve plate whereby movement of said valve plate by said torque motor positions the valve plate closer to one of said nozzles and farther from the other to increase the dynamic fluid pressure in the one nozzle and decrease the dynamic fluid pressure in the other, means directing said fluid pressures against opposite ends of said valve member to shift the same in response to such imbalanced fluid pressures, and expansible chamber members attached to said valve plate at opposite sides thereof and to said housing to enclose said nozzles, and passage means from the interiors of said chamber members for conducting fluid discharging from said nozzles to a return passage.

2. Valve means according to claim 1 wherein said valve means comprises a four-way valve having a fluid return passage and a pair of pressure output passages, said valve member being movable in opposite directions to connect one of said output passages to said pressure source and simultaneously connect the other output passage to said fluid return passage.

3. Valve means according to claim 1 wherein said valve plate is perforated to provide fluid flow therethrough, and a passage from the interior of one of said expansible chambers to a fluid return passage.

4. Valve means according to claim 2 wherein said valve plate is perforated to provide fluid flow therethrough, and a fluid passage from the interior of one of said expansible chambers to said fluid return passage.

5. Valve means according to claim 1 wherein the means normally centering said valve member comprises balanced springs acting against said opposite ends of said valve member.

6. Valve means according to claim 1 wherein said expansible chamber members comprise generally cylindrical bellows members generally coaxial with said nozzles attached peripherally to opposite sides of said valve plate and attached at their outer ends to fixed portions of said valve means.

7. Valve means according to claim 6 wherein said valve plate is perforated to provide fluid flow therethrough, and a passage from the interior of one of said bellows members to a fluid return passage.

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