US2876796A

US2876796A - Minimum displacement balanced control valve

Info

Publication number: US2876796A
Application number: US468302A
Authority: US
Inventors: Stuart D Pool; Edward M Melin
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1954-11-12
Filing date: 1954-11-12
Publication date: 1959-03-10
Anticipated expiration: 1976-03-10

Description

March 10, 1959 I s. D. POOL ETAL 2,876,796

MINIMUM DISPLACEMENT BALANCED CONTROL VALVE Filed Nov. 12. 1954 2 Sheets-Shet 1 cry/m5? A Hui q; cm ma 3 Z;z1/e nfor5: faarl D. Pool v {award Melz'n Mo. "an-ra March 10, 1959 s. D. POOL ETAL 2,876,796

- MINIMUM DISPLACEMENT BALANCED CONTROL VALVE Filed Nov. 12 1954 2 Sheets-Sheet 2 J8 U A 14 nyvENToRs ggzzrazz fire! United States atent MINIMUM DISPLACEMENT BALANCED CONTROL VALVE Stuart D. Pool, Moline, and Edward Island, 111., assignors to International pany, a corporation of New Jersey Application November 12, 1954, Serial No. 468,302 7 Claims. (Cl. 137-622) M. Melin, Rock Harvester Zom- This invention relates to a new and improved control valve.

The operation of much present day equipment and apparatus is being performed by hydraulic mechanisms for the reason that hydraulics lends itself to remote positioning and efliciency of operation. The search for control valves of a type to efliciently direct fluid to various hydraulic control units has been unending.

It is, therefore, a principal object of the present invention to provide a control valve for effecting the efficient and easy directing of fluid under pressure to various hydraulic mechanisms.

An important object of this invention is the provision of a control valve for hydraulic systems wherein the valve has a balanced construction in which there is no back pressure to aifect or throw the valve at any position of the valve spool.

A still further important object of this invention is to supply a control valve for hydraulic mechanisms in which the movement of the actuating portion of the valve is relatively small.

Another and still further important object and advantage of this invention is to provide a control valve for hydraulic systems in which a sliding spool is employed and wherein no position of the spool will entirely block flow of fluid into or out of the valve.

A still further important object of this invention is the provision of a control valve for the operation of hydraulic apparatus and wherein the control valve may be used in series or tandem.

Another important object of this invention is to provide a control valve with a sliding spool having symmetrical lands about the center and slidable within a housing having symmetrical lands about a center.

Other and further objects and advantages of this invention will become apparent from the disclosures in the following specification and accompanying drawing.

In the drawing:

Fig. 1 shows a transverse sectional view taken through the control valve of this invention and having representative cylinders to be operated shown in association therewith.

Fig. 2 is a sectional view of the valve as shown in Fig. 1 but having the spool thereof moved toward one end.

Fig. 3 is another sectional view of the valve as shown in Figs. 1 and 2 but with the spool moved to the other end.

As shown in the drawing, the reference numeral indicates generally a housing for the valve which is provided with a longitudinally extending bore 11 within which a spool or slide valve member 12 is slidably positioned. The housing 10 is provided with an inlet 13 and an exhaust outlet 14. Fluid under pressure is delivered to the inlet 13 in the housing and fluid may be removed from the housing through the exhaust port 14. A longitudinally extending passage 15 is positioned in the housing and lies parallel to the central bore 11. This passage 15 is in association with the inlet port 13 and receives fluid under pressure from the inlet 13.

Radial passages

16, 17 and 18 communicate with the passage 15 and the central bore 11 at both ends and at the center of the spool 12. It is thus evident that as fluid under pressure is delivered to the control valve through the inlet port 13 this fluid will be dispersed through the passage 15 and thereafter delivered radially inwardly through the

passages

16, 17 and 18 to the central bore 11 wherein the fluid is diverted as desired by means of the spool or slide valve 12. It is this symmetrical feeding of fluid to both ends and the center simultaneously that contributes to the short stroke and the lack of resistance to movement of the operating spool.

A second longitudinally extending passage 19 is positioned in the housing 10 and lies parallel to the central bore 11 and spaced apart from the longitudinally extending passage 15. Here again

radial passages

20, 21 and 22 join the longitudinally extending passage 19 and the central bore 11. In the same manner that the passage 15 joins with the inlet port 13 the passage 19 forms an integral part of the exhaust port 14, thus providing for communication of the central bore 11 with the exhaust port 14 at the spaced points of the

radial passages

20, 21 and 22.

The spool 12 is equipped with a centrally disposed an nular groove 23 which in the position of the device as shown in the drawing permits passage of fluid from the inlet 13 through the passage 15, through the passage 18, around the annular groove 23, and thence to the radial passage 22 leading to the longitudinally disposed passage 19. However, a spring retained ball valve 24 is adapted to engage a seat 24a within the passage 22. The ball valve 24 is urged toward closed position against the seat 24a by means of a coil spring 25. The spring 25 may be of any desired strength and the ball 24 and spring 25 combine to provide a. relief or by-pass for the control valve in the event some predetermined pressure is exceeded, whereafter fluid may be by-passed from the inlet of the control valve directly to the exhaust of the control valve.

The spool valve 12 further includes a plurality of alternate annular lands and annular grooves spaced outwardly and symmetrically from the central annular groove 23 as follows: Spaced apart

annular lands

26, 27 and 28 on one side of the annular groove 23 and spaced apart

annular lands

29, 30 and 31 on the other side of the central annular groove 23. Intermediate the

annular lands

26, 27 and 28 on the one side of the spool are

annular grooves

32 and 33, and similarly on the other side between the

annular lands

29, 30 and 31 are annular grooves 34 and 35. The central bore 11 of the valve housing 10 is provided with spaced apart internal annular grooves or

recesses

36, 37, 38, 39, 40 and 41. The width of the annular lands and annular grooves are all substantially the same except for the central annular groove 23 which is considerably wider.

In order to complete the description of the construction of the spool or slide member 12, it should also be explained that the spool has a central passage 42 and spaced apart radial passages 43 and 44 which thus join the spaced

annular grooves

32 and 33. Similarly, another central passage 45 spaced longitudinally apart from the passage 42 adjoins

radial passages

46 and 47 to thereupon permit fiuid communication between the annular grooves 34 and 35. I

The outlets for the cylinders A and B are shown in the drawing at 48 and 49. These ports 48 and 49 are located within the housing 10 at the position of the

spaced lands

26 and 29 in the spool 12 when that spool is centered within the housing as shown in the'drawing. The slide spool valve 12 is provided with a laterally extending portion 50 projecting from one end of the housing 10 and 3 has a transverse opening 51 in the outer end thereof for actuation of the slide valve by a manual pushing and/or pulling in the direction of the arrow 52 for filling the cylinder A with fluid and exhausting fluid from the cylinder B and moving the slide valve in the direction of the arrow 53 in order to direct fluid under pressure to the cylinder B and exhaust fluid from cylinder A. Obviously movements of the slide valve 12 perform the function of oppositely extending and/ or retracting

piston rods

54 and 55 projecting downwardly from cylinder A as shown at 56 and from cylinder B as shown at 57, respectively. A flexible conduit 53 joins the port 48 with the cylinder A and similarly a flexible conduit '59 joins the port 49 with the cylinder B. The cylinders A and B are joined at their lower ends by conduit 60. Thus when fluid under pressure is delivered to the conduit 58 the piston rod 54 from cylinder A is extended and simultaneously fluid under pressure is delivered to the lower end of the cylinder B, causing the piston rod 55 to be retracted. Conversely when .fluid under pressure is delivered to the conduit 59 piston rod 55 is extended and piston rod 54 is retracted.

Although two cylinders have been shown in series or tandem connection for operation by the control valve of this invention, it should be understood that merely one hydraulic cylinder may be operated by the control valve wherein fluid under pressure is delivered to either the top or bottom of the one cylinder whereupon the piston rod will be either extended or retracted. Or, it is entirely possible that more than two cylinders may be operated by this single control valve.

It should be noted that the radial passages 16 and 17 feed fluid from the inlet 13 to the endmost internal

annular recesses

36 and 41 and that the radial passages 20 and 21 receive fluid from the penultimate internal

annular recesses

37 and 40 at each end of the housing bore. The ports 48 and 49 for delivering to or receiving fluid from the cylinders A and B are joined to the innermost internal

annular recesses

39 and 38 respectively of the housing bore.

The spool 12 has symmetrical annular grooves 65 and 66 in the

end lands

28 and 31 for the purpose of receiving

sealing rings

67 and 68 respectively. The sealing rings permit sliding of the spool within the housing bore without permitting escape of fluids endwise from the control valve.

In the operation of the control valve of this invention the centered position of the spool 12, as shown in the drawing, permits fluid under pressure to be uniformly exhausted about the symmetrical ends of the valve. At one end the fluid is delivered from the inlet 13 to the radial passage 16 and thence to the exhaust port 14 by reason of the slight overlapping of the annular recess 36 in the housing communicating with the annular groove 33 in the spool 12 which engages by a similar slight overlapping the annular recess 37 in the housing 10. The radial passage 20 leading to the exhaust port 14 is in com munication with the annular recess 37 and thus fluid is directly discharged from the inlet to the exhaust. Similarly fluid under pressure delivered to the inlet 13 is simultaneously permitted passage through the radial conduit 17 at the other end of the valve forcommunication with the annular recess 41 in the housing 10. A slight overlapping of the annular recess 41 with the annular groove 35 in the spool 12 provides for passage of the fluid to that annular channel 35 and thence by reason of a further and similar slight overlapping with the internal annular groove or recess 41) in the housing 10 fluid reaches that recess. The radial passage 21 is in direct communication with the annular groove 40 and thus carries fluid from the inlet 13 to the longitudinally extending passage 19 and thence outwardly through the exhaust port 14. The pressures on both ends of the symmetrically designed control valve of this invention are thus balanced so the spool or slide valve 12 may beeasily manually moved savanna from one position to another to efiect shifting of the direction of fluid through thp control valve. The entire movement of the control. valve spool 12 is relatively minute and yet it accomplishes all of the various functions of the valve. It will be seen that the overlapping of the annular grooves in the spool 12 with certain of the internal annular recesses in the housing 10 is relatively slight making it necessary only to move the slide valve a relatively short distance whereupon communication between the recesses is made larger or cut ofl entirely depending upon the direction of movement of the spool 12.

Let us assume, for example, that the spool 12 is moved in a leftward direction as viewed in Figure 2 of the drawing and as shown by the arrow 52 in Figure 1. Overall movement of the spool 12 is relatively slight. This slight movement is in the order of one to two hundredths of an inch. When this movement of the spool valve occurs in the direction of the arrow 52, and as shown in Figure 2 the land 28 on the spool bars the admission of incoming fluid under pressure from the inlet 13 to the annular groove 33 in the spool. However, the other end of the control valve is merely opened a greater amount whereupon fluid is admitted to the annular groove 35, but here again the land 36 bars admission of this incoming fluid to the annular groove 40 in the housing so that the incoming fluid does not reach the exhaust port 14 from either end. Incoming fluid is also simultaneously delivered to the centrally disposed radial passage 18 whereupon this fluid enters the wide annular groove 23 in the slide valve 12 whereafter it communicates directly with the annular recess 39 disposed internally of the housing for admission of the fluid to the cylinder A. Thus there is an extension of the piston rod 54 of cylinder A when the spool 12 is moved to its position as shown in Figure 2. Simultaneously with the admission of fluid under pressure to the cylinder A there is an exhausting of fluid from cylinder B through the conduit 59 to the port 49 through the internal annular recess 38 in the housing which now communicates directly with the annular groove 32 in the spool 12. Thus by reason of the radial and central passages 43, 42 and 44 fluid from the cylinders is discharged through the annular groove 37 in the housing to the exhaust port 14.

Conversely when the spool 12 moves in a rightward direction, as indicated by the arrow 53 in Figure 1 and as shown in Figure 3 of the drawing, fluid under pressure from the inlet 13 of the control valve is delivered to the top of the cylinder B through the flexible conduit 59 and exhausted by retracting of the piston rod '54 in the cylinder A and thence backwardly through the flexible conduit 58 to the control valve and thereafter out the exhaust port 14 in the same manner as described for the other movement of the control valve.

It is apparent that herein is provided a control valve for cylinders of the hydraulic type to be operated and that such control valve operates with a balanced construction wherein there is no back pressure on either side which might affect the throw of the valve spool as in ordinary control valves. Further, the movement of the spool valve need only be relatively minute to accomplish the changes in direction of the flow of fluid under pressure and/or the movement of the control valve to the neutral position wherein fluid is continuously exhausted directed from the inlet port to the exhaust port. Obviously there are many applications for a control valve of this type and it is applicants intention to inelude all of the possible uses to which the controt valve may be put as well as the mechanical construction of the valve which may be changed in detail Without departing from the principles disclosed herein and we, therefore, do not propose limiting the patent granted hereon otherwise than as necessitated by the appended claims.

What is claimed is:

1. A control valve comprising a housing, said housing having an elongated bore, a spool slidably mounted in said bore, said spool having a plurality of alternately spaced annular lands and annular grooves symmetrical about a center line, said elongated bore of the housing having a plurality of spaced apart internal annular recesses symmetrical about a center line and each of said spaced apart internal annular recesses in the bore of said housing disposed substantially opposite one of the spaced annular lands on said spool when the spool is centered within said housing, said communicating with both of the endmost internal annular recesses of the elongated bore, said housing having an exhaust outlet simultaneously communicating with the penultimate internal annular recesses at each end of the elongated bore, said housing having separate ports joining with the two innermost internal annular recesses, said spool having spaced apart central passages and radial passages communicating with the central passages at the positions of the endmost and the penultimate annular grooves of each end of the spool, said spool in its centered position in said housing having its outer and penultimate annular lands slightly open with respect to the outer and penultimate annular recesses in the housing at both ends thereof, and means for slidably moving said spool within said bore.

housing having an inlet simultaneously 2. A device as set forth in claim 1 in which the annular 25 grooves of the spool are substantially the same width as the internal annular recesses of the elongated bore.

3. A device as set forth in claim 1 in which said inlet includes said housing having a passage therein disposed parallel to said bore and adjoining radial passages at spaced positions in alignment with the endmost internal annular recesses.

4. A device as set forth in claim 1 in which said exhaust outlet includes said housing having a passage therein disposed parallel to said bore and adjoining radial passages at spaced positions in alignment with the penultimate internal annular recesses at both ends of the housing.

5. A device as set forth in claim 3 in which said exhaust outlet includes said housing having a second passage therein disposed parallel to said bore and adjoining radial passages at spaced positions in alignment with the penultimate internal annular recesses at both ends of the housing.

6. A device as set forth in claim has a centrally disposed annular groove between the innermost annular lands, a radial passage in said housing communicating between the passage therein and the central annular groove of the spool, a second radial passage in said housing communicating between the second passage and the central annular groove of the spool, and pressure relief valve means disposed in said second radial passage.

7. A device as set forth in claim 6 in which said central annular groove is wider than the other annular grooves of the spool.

References Cited in the file of this patent UNITED STATES PATENTS 5 in which the spool 2,331,108 De Ganahl Oct. 5, 1943 2,486,087 Wright Oct. 25, 1949 2,600,746 Ernst June 17, 1952 2,636,566 Jedrziewski Apr. 28, 1953