Patented Dec. 3, 1946 _UNITED STATES PATENT OFFICE Max A. Mathys, Detroit, Mich., asslgnor to Ex Ce‘ll-O Corporation, Detroit, Mich., a corpora tion of Michigan Application July 14, 1943. Serial No. 494,609 5 claims. (ci. 1st-_ssi 1 The present invention relates to improvements in relief valves for fluid pressure systems, and has particular reference to a new and improved valve adapted to divert fluid from a pressure line when the pressure therein tends to rise above a pre determined maximum. One of the objects of the present invention is to provide a novel relief valve in which the clos ing pressure is more closely related to the open-ing pressure than in the case of conventional re lief valves of the poppet type or piston type. Another object is to provide a new and im~` - proved relief v alve in which the closing pressure - effective to teminste the n_uid flow is substan 2 one embodiment of the invention adapted pri marily for use as a working pressure relief valve in a hydraulic transmission system. _ For purposes of illustration, the valve Il! is shown connected in a simple system having a pump II taking hy draulic fluid through an intake line I2 from a supply reservoir I3. The pump I-I has a discharge line Il for conducting fluid under pressure to a point of u_se, such as a hydraulic actuator (not shown). ' -« Y . The valve I0 is connected in the system through an inlet pressure line I! branching from the pump discharge line I4, and an outlet relief line I6 lead - ing back to the reservoir I3, and in normal use is operable to bypass any excess iiuid so as to . tially the same as the opening pressure effective 16 limit the discharge pressure of the pump to _a to Iinitiate the fluid flow, said pressures difier ` ' predetermined adjustable maximum working pres ing, if at all, only to the slightest possible extent. Still 'another object is to provide a novel relief In its exemplary form, the valve II) comprises a valve in which av dynamic force generated as an main body I1 preferably cylindrical in shape. 20 incident to a change in direction of ñuid flow One end of the body I1 is -formed with a rela through the valve is utilized to supplement the tivelylarge bore I8 constituting a spring cham closing pressure of a spring in opposition to the ber and connected through an outlet passage I9 normal opening pressure of the fluid at the inlet -to the relief line Il. A screw plug 20 is adjust-l acting on the valve member. ably threaded Into the outer endA of the bore I8 Other objects and advantages will become ap ' 25 to close the latter, and is normally secured in parent asthe description proceeds. ' position of adjustment by means of a lock nut - Inthe accompanying drawings, ' ' 2I threaded thereon against the end of the body Figure 1 is a fragmentary view of the hydraulic I1. Also threaded onto the outer yend of the screw >transmission system including a relief valve in' plug 2li to enclose the latter is a cap nut 22. 30 longitudinal section and on an enlarged scale em-A The opposite end of the valve body I1 is formed bodying the features of my invention. ' with a vrelatively-small valve bore 23 opening co Figs. 2 and 3 are transverse sectional views of axially to the bore I8. The outer end of the valve the valve taken along lines 2,-2 and 3--3 of Fig. 1. - > _bore 23 is formed with a >counterbore 24 closed Fig. 4' is a. longitudinal sectional view of a re lief valve constituting a’modiiled form of the I ' Invention. ~Ii’ig. 5 is a transverse sectional view taken along line 5-5 of Fig. 4. by a screw plug 25 and constituting a pressure chamber. Formed in the inner peripheral sur- ‘ face of the valve bore 23 intermediate its ends is an annular groove 2l connected through an in let passage 21 to the pressure line I5. A restricted Fig. 6 is a fragmentary view partially in lon snubber channel or passage 28 opens from the gitudinal section of a relief valve constituting 40 passage 21 to the chamber 2| to conduct fluid another modi-fled form of the invention. thereto at the valve inlet pressure. Fig. 7 is a transverse sectional view taken along A sleeve valve member 29 extends through the line 1--1 of Fig. 6. valve bore 23 with a snug sliding fit. The outer ì While the invention is susceptible of various end of the valve member 29 is closed, and pre~modifications and alternative constructions, 1_ sents a valve opening pressure area exposed to the have shown in the drawings and'will herein de 'pressure in the chamber 24. The inner end por scribe in detail the preferred embodiment; but it tion of the member 29~-is formed with an axial ' is to- be understood that I do not thereby intend -bore 30 opening to the chamber I8. The mem to limit the inventionto the specific form dis ber 29 is >also formed in the outer periphery with closed, but intend to cover al1 modifications and an annular groove I_I connected through a plu alternative constructions falling within the spirit ` rality of spaced radial ports 32 with the inner and scope of the invention as expressed in the end of the bore 30, and adapted for movement appended claims. into and out of communication with the'groove Referring more particularly to the drawings, 2t. vThus, the grooves 26 and 3| constitute the the valve IU shown in Figs. l to 3 constitutes 2,411,930 3 4 valve ports, and are movable out of communica end portion of the bore 31 opens directly to the inlet passage 21H, and is adapted to be closed by a screw plug 4I. The outer end portion of the bore 31, which preferably is enlarged in diameter to facilitate insertion and removal of the plug 4I, is likewise adapted to be closed by a screw plug 42, and is connected to the pressure chamber 24a directly through a. restricted port 43, and also tion to close the valve I0, and into varying degrees of registration to open the valve. The path of flow through the valve I0 is from the inlet pas sage 21 through the ports 2B and 3I, and radially through the ports 32 into the bore 30, and thence at right angles through the bore 3|J and chamber I8 to the outlet passage I9. The position of the valve member 29 is con through a passage including a check valve 44. trolled by a coiled compression spring 33 acting 10 In the present instance, the check valve 44 has an thereon in a direction to close the valve I 0 in opposition to a valve openingr pressure exerted by , inlet passage 45 opening from the bore 31 to a the fluid at the inlet»I 21. The fluid ypressure is transmitted from the inlet passage 21 through the snubber passage 28 to the chamber 24 wherein normally urged by a light compression spring 49 it acts against the end face area of the valve member 29. Thus, the valve opening area is of ñxed size so that the opening pressure varies only as the pressure of the inlet fluid, and is not di of the passage 45. When the valve Ill*l is to be adapted for pump pressure control to operate in substantially the transverse bore 46 in turn open to the chamber 24* through a` connecting bore 41, and a ball 48 . within the bore 43 against a seat 50 at the end same manner as the valve I0 of Figs. 1 to 3, the rectly disposed in the path of fluid iiow through 20 plug 4I is removed and the plug 42 is inserted. the valve I0. The inlet passage 21‘l is then connected through The spring 33 is disposed within the chamber the bore 31 and the port 43 to the pressure cham-~ I8, and seats at the outer end statically against ber 24a. When the valve I0“ is to be adapted,the screw plug 20 about a centering pilot 34. The for orifice pressure control, the plug 4I is inserted inner end of the spring 33 engages a spring pilot 25 andthe plug 42 is removed, and the bore 31 is washer 35 fixed on the valve member 29. The connected to the orifice control line 3'8. In this valve closing pressure exerted by the spring 33 condition, the passage 21ß is blocked from the may be varied by adjusting the screw plug 20 chamber 24“ so that the valve I0' is not respon which is provided with a hexagon head 36 to facilitate such adjustment. ’ . sive to the inlet pressure from the pump dis 30 charge line I 5*. In both adaptations, pressure In operation, when the fluid pressure in the inlet line I5 from the discharge line I4 of the » pump I I is below the normal working pressure, at which the valve In is set to open, the pressure of the fluid within the chamber 24 acting on the 36 valve member 29 is> insufhclent to overcome the force of the spring 33, so that the ports 29 and 3I are completely out of registration to interrupt the bypass or relief of iiuid. As the pressure in rises are freely transmitted through the check valve 44 to the pressure chamber 24‘, but in the event of a drop in the control pressure the result ing closing movement of the valve member 29“ is snubbed or dampened due to the restriction to âlêiid egress from the chamberv through the port In oriilce pressure control, the operation of the valve is responsive to the pressure established in the chamber 24 rises, it acts against the valve 40 -the line 33,by the flow restriction through the member 29 to move the port 3| progressively oriilce 39. Such oriñce may be arranged in vari toward and then into varying degrees of regis ous types of control systems, for example to re tration with the port 25 to open the valve. With ceive and meter ñuid discharging from an actu the valve in open position, av portion of the iluid ator which in turn is motivated by fluid under from the inlet line I5 is bypassed. The change 45 pressure from the pump II, as in the patent to Alden No. 2,000,553. in direction of flow of the fluid issuing from theradial ports 32 within the bore 30 of the valve Figs. 6 and 7 disclose another modiñed form member 29 generates a dynamic force which acts of the invention which is generally similar to that on the valve member 29 in a direction to supple-- ^ shown in Figs. 4 and 5 and, therefore, correspond ment the force oi' the spring 33. Variation in the, 50 ing parts are identified by like reference numerals, volume of flow through the valve will result in a with the addition of the subscript "b”. In this corresponding variation in the dynamic force. case,` a valve sleeve 5I is ñxed in the valve bore Because of the control factors ofthe valve I0, 23h to receive the valve member 29h, and is Aformed the opening pressure and the closing pressure are with an annular groove 52- in communication approximately the same, and the desired maxi 55 with the inlet passage 21'?. 'I‘he sleeve 5I is formed »mum working pressure is effectively maintained' with a plurality of peripheral ports 53 opening within an extremely small range of variation. Figs. 4 and 5 illustrate a modiñed form of relief valve which is convertible for use either as a pump pressure control, as inthe case oi the form of Figs. 1 to 3, or as an oriñce pressure control. The construction is generally similar to that dis closed in Figs.v 1 to 3, and corresponding parts are, therefore, identified by the same reference numerals, with the added subscript “a”, In the modified form of Figs. 4 and 5, the outer end oi' the valve bore 23* does not open to the extreme end of the body I1, but terminates short thereof, and is diametrically enlarged to from the groove 52 to the inner bore for corn munication with the groove 3 Ib in the valve mem-y ber 29h. ` ' 'I'he valve member 29b isyso constructed that the downward dynamic ñow reaction tending to urge the valve toward closed position will in crease more rapidly than in the preceding forms upon an increase in the rate of flow so as to eii’ect rapid closing. The ports 32b in the valve >member 29b and the ports 53 in the sleeve 5I are radially inclined inwardly toward the closed end of the valve member, and the latter is formed in ' termediate' the ports 32b with a curved central _ define the pressure chamber 24B. Formed in the 70 projection or baille 54 extending longitudinally body I1 is a longitudinal ’bore 31 for connecting the pressure chamber 24'» optionally either to the inlet passage 215. or'to an outside line 38 leading from the upstream side of an adjustable of the bore 30". Whereas, in the first two forms, duid passing through the valve is caused to change direction _abruptly substantially at ninety degrees, the fluid in the last form will change direction pressure control oriilce 39in _a line 40. The- inner 75 y at an acute angle, vandtlne dynamic force ot the ¿Y _ 9,411,930 a valve member reciprocable in said bore closed ?uid will have an increased longitudinal com at the end adjacent said pressure chamber and ponent tending to close the valve. formed with an axial bore opening to said spring chamber and with peripheral ports opening to I claim as my invention: 1. A relief valve comprising, in combination, said last mentioned bore and movable in-to and a valve body having a valve bore, a pressure inlet 5 out of communication with said iirst mentioned opening to lthe side of said bore and a relief out ports and radially inclined in the same direc let. a pressure responsive valve member» recipro tion as said inlet ports, coiled compression spring cable in said bore and having a port in the pe means disposed in said spring chamber and act riphery movable into and out of communication ing on said valve member to urge said member with said inlet and a longitudinal bore closed at 10 in said one direction ¿toward closed position, pas one end and establishing communication through sage means ior directing fluid from said inlet the other endbetween said port and said outlet, ports to said pressure chamber to act on the l saidbody being -formed with s, pressure chamber closed end of said valve member in opposition to f open Ato one end‘of said bore and a passage con the force of said spring means and the kinetic :necting said inlet to said chamber, said valve 15 energy acting in the direction of -the spring force member having a pressure area at one end ex generated by the fluid in said last mentioned bore, posed to the pressure in said chamber, spring and a balde at the inner endïeof said last men tioned bore for directingeiluidfrom said last men means acting on the other end of said valve member in a direction to close said valve in op position to said pressure, said port opening to 20 said longitudinal bore at an angle inclined ra dially inwardly toward the closed end of said lon gitudinal bore, and a baille in the closed end of _tioned ports outwardly -toward said spring charn ber. 4. A relief valve comprising, in combination, a body having a valve bore opening at one end to l a pressure chamber and at the other »end to a said longitudinal bore for directing the fluid issu spring chamber and formed with inlet ports ra ingfrom said port through a sharp turn and then 25 diallyjnclined in one„direction longitudinally of longitudinally out of said valve member «to said said -bore, a valve_ member reciprocable in said outlet. l 2. A relief valve comprising, in combination, an elongated body having- a large bore in one end and a small valve bore opening coaxially to the 3b bore and formed with an axial bore opening to y‘saijdesllvring opening to chamber and with peripheral ports said last mentioned bore and mov y into and out of communication with said inner end of said large bore and having an outlet I .able ‘inletports and radially inclined in said one direc passage opening from said large bore, the outer ---‘. tion, coiled compression spring means disposed end of said valve bore deñning a pressure cham- " in said spring chamber and acting on said valve ber and said valve bore being formed interme memberr to urge said member in said one direc diate its ends with an inlet port connected 35 tion »toward closed position. and passage means through a restricted flow passage to said cham for directing iluid from said inlet ports to said ber, a branch passage opening from said inlet pressure chamber to act on said valve member in port in parallel with said restricted passage to opposition to the force of said spring means and » said chamber, a one-way check valve in said the kinetic energy acting in the direction of the branch passage for admitting iiuid to said cham- 40 spring torce generated by the fluid in the bore ber, a valve member movable in said valve bore valve member. with a sliding fit and formed with a longitudinal . of 5.said A relief valve comprising, in combination. a passage opening to said\ large bore and with a body having a valve bore opening at one end to peripheral valve port opening to said longitudi- . a pressure chamber and at the other end to a nal passage, one end yof said valve member pre- 45. spring chamber and formed with a pressure inlet. senting a closed end surface exposed to the pres a valve sleeve fixed in said bore and formed with sure in Vsaid chamber tending to move said 'valve inlet ports in communication with said inlet and member in a direction to bring said ports into radially inclined in one direction longitudinalLv communication, and a coiled compression spring ci said bore, a valve member reciprocable in said in said large bore acting on said valve member 50 sleeve and formed with an axial bore opening to in a direction opposite to said first mentioned said spring chamber and with valve ports open direction, the kinetic energy created by the .ing to said `last mentioned bore and adapted Yfor change of direction of flowthrough said valve communication with said inlet ports and radially member supplementing l’the pressure of said inclined in said direction, coiled compression spring to act on said valve member in opposition 55 ».springmeans disposed in said spring chamber to the pressure in said chamber. and acting on said valve member to urge said 3. A relief valve comprising, in combination, a body having a valve bore opening at one end to a pressure chamber and at the other end to a member in said one direction. and a restricted passage for directing fluid from said'inlet to said spring chamber and formed with inlet ports ra- ¿o pressure chamber to act on saidl valve member dially inclined upwardly and outwardly with re spect to the pressure chamber end of said bore, in opposition to the force of said spring means. ' ' A. MATHYS.