US2636566A - Governor valve for variable pitch propellers - Google Patents

Description

A nl 28, 1953 c. M. JEDRZIEWSKI GOVERNQB. -VALVE FOR VARIABLE PITCH PROPELLERS Filed Jan. 25, 1948 2 SHEETS-SHEET l iii! ' INVENTOR [beslferMhkzfi'zlbnsxzi 7m 4 M ATTORNEY April 28, 1953 c. M. JEDRZIEWSKI GOVERNOR VALVE FOR VARIABLE PITCH PROPELLERS Filed Jan 23, l 948 2 SHEETSSHEET 2 ZZZ i ZZ a L .1 w QUHMMM HT WWWHH PH %w\ 4 t w Z Z QM m M M m M M w w w w w WZ n MV/ J :wwwmn humw m w x? v E 4. w M M INVENTOR lr'beslferMkf-z'drziywsxi.

ATTORNEY Patenteci Apr. 28, 1953 :ioierzicze Sinister"ii/E. 'Jeflrzietvski, Manel'ies'terffldnni, es-

signor to United Aircraft 1G0r1'ior2ttion, East Hartford, "Gonn, ca morporfitiam iof Delaware e Claims.

Tlhis invention relates to enkimproveld control val e an fi ds particular utility h n e a governor controlling the pitoh ,olf afhy ira llicja ll y control d i h propellerobject ofthis 'inventionfisan improved 0101,1- trolvellve.

Another object of this invention is 'to"in'crease the sensitivity of a speed governor controlled Valve.

.A iurther object of this invention is a. speed ooritr'olisystem whose .normal automatically ,controlled range is controlled by a governor .conteim inge ,vaJlve thetdirects hydraulic fluid to a speed chan ing mechanism and in which the governor acts as .a. single Lasting [governor except 'for'large speedehanges whenit is jdqublevacting.

A .stillifurther .Objeet' resides in the provision in afip'eled-governor, controllable-pitch-pitopel-ler system of the character described of .controllebile resilient mea s ..'for opposing ee'ntrifug'ell twistin mnmentsqactingon'the propeller bladesto prevent them from turning 91' ailowing thenito turn to.- ward low pitch 'jforjsma'll-speed changes in cornhinat'ian with other controllable resilient means for assisting the centrifugal twisting moments acting Qnthe propellerbledes to turrrthe bleiies toward their low pitch i012 large speed changes. I ther objects end advantages will Joe more particularly pointed "out hereinafter .or beeoine apparent as the description proeee'ds.

in the .eecomp nying drawings in'whie'h like 'ingithescope of theinvenjtion .as setjforth in the app nded .cl imslInthe drawings Eig. I1 is a diagrammatic illustration of the bimeipalemme tsof a contiiollable pitch propel-- iersystem including a constant speed governor emhq ing the invention. I

Fig. 2 e sectional view one somewhat enlerged scale of a valve and valve housing in ,a. governor illustrziting;the"on'speed condition. I

Fig.3 is a. View oi'Lthe valve'and valve housing iilustrated in Fig. 2 showing .the ioVer-speedeoniiiti'on' .or Ton-speed .Conidtion if leakage is present.

v Fig. 51115 2. View {of the valvewand Valve housing iilustrajted in Fig. 2 showing t e underespeed lcpndition."

j' tie- '2 sh ing e i ei' u ide on'."

V e e e e teem th Sub ec ma te 6 he s mivet .n th ."ibeen "Shawn in qb n iien en er ilewi he rp i w inl-si efit No. 2;, i02j065, Propeller Control, issued ito Erie June 11, 1 9 .61. 1 m 228M "r a r n Propeller controlissnegi to 'Lrlje Martin April 21 1942, which eferenoesrney bet'teiken for egniore compi'etedisplosure. propller'jhesieeenonly "diagrammatically illustrated Fi'gflgin whi'ohe propeller generally viniiiqeite i"by numeral it, inc id a hub *Zr IfliI Efi -thei fli 'e' ile .i've s t me u w defiwit eie iirelit io i e d ell d s o ed tim r w i g s im '5 nl w 1 Wb is inqifi fil- Th ll ui li QI l lf l b pi er e n ti ie the m'sm l r 'la e an th p me l r dr ve sha t 'ih she n mr d j d s i t rprqi l e were 1 is m n i a socket "in the usuztlmanner *with suitable f ghtiifriction bearings 29 interpqsedhetween asojcket ntmem 7 s ffiaiie W on t e e n the blafie soithet the bla'des ere'freeiy 'rotatekile :a utith axes in p tch i ane ne di ii is- E h a e isx ov ded 'Qn i in e nd i i h the b membe 12 with e s er v e 2. fi liof w hi'eh gear segtors mesh ith gtrmester .gear 23 f rh' l' e the hub memb '1? 1 m ot t about the axis of Shaft i 4 .MasterJgeer "2B is i i}- teera wit "rotatable c m' I r iai edthro ehe r a d f meek. ism in lu ng sbQi t er e' l e rs I. l th we e wh h is sho n ge end eboperetijng' up ositeiy Qirected tationery a w iedia it a e earn d by annula in e .Qi'fiimier me e a so -sh res ee e emit he view r e h b r ded with a sleeve aimed f r f eeie e tlipn n a where is afieis e isi n iferm g by e threaded tube carried'by shaft 14, gro n: the ejbove (1'8- s cription .angi ,referenqe, Wil .be evideritthejt a. pre e 'dexen e .o m i eiipi i i si e 9 iii to "3 wi we h sie iv m e ans chees t ii i flq 311 9f rbpe r W de? innniso'nf. I r

Gilis oon'du'etecfi fr'ome- Werner, g'enre iiidisease "a t we, ate @iihde'iee @fihrmigh two um conduits mend a rid-comrnmiiqelting enema-1s *f iii end-5Qleading? r grcqie'ilerrib. *Tli'e overr e se s o e 'ect velye n' q 1 1 9 1t fines 4.5 t ge re pressu e end em t the et e fI i wit fir i I er to W W rp si 31 ans fi fin fi he 111mb of the pr peller fblle'des *Fi-gi5 is a view of the 'velve and valve housing 55 therqiiiredamount to-"meintain constantsbed of the engine and propeller. Fluid is distributed to either side of the piston 36 by means well known to the art and particularly illustrated in Patents 2,402,065 and 2,280,714, referred to above. It will be understood that when one side of the piston is connected to pressure fluid through one of the above fluid lines, the fluid on the other side of the piston is connected to drain through the other line in the usual manner.

The governor is shown diagrammatically in Fig. 1 to which reference is now made. The governor comprises a rotatable shaft 52 driven by gear 42 which engages a gear (not shown) carried by the propeller drive shaft [4 in timed relation with the engine. A flange 54 which is fixed to the upper end of shaft 52 pivotally supports a pair of fly weights 56. The shaft 52 may be made in a single piece, as shown, or if desired may comprise several sections connected together, as by splined joints.

Intermediate its ends the shaft 52 carries a gear 58 meshing with a gear 60 supported on a hollow axle journalled in a governor body 52 to form a booster pump." Hydraulic fluid is supplied to this pump from any convenient source, the source herein being the engine lubricating pump 54 which is supplied through a conduit 96 from the engine oil tank, or reservoir 61 and discharges through conduit 58, duct H3 and branch passage i2 to the intake of the booster pump. A relief valve H limits the pressure in conduit 63 and in conduit 69 leading to the engine lubricating system. Oil from the booster pump flows through channel 14, through ports in hollow shaft 52 into annular pressure chamber 18 between lands l8 and B of a hollow piston rod of a governor pilot valve 82 which is vertically reciprocable in the hollow shaft 52 by the fly weights 56 and speeder spring 84 which act oppositely on an anti-friction bearing flange 86 on piston rod 82.

When the pilot valve 82 is forced upwardly by an increase in governor revolutions per minute reacting upon the fly weights 56 to overcome the balance between said fly weights and speeder spring 84, hereinafter called overspeed condition, pressure oil supplied by the booster pump 58, 50 flows from chamber 16 through ports in shaft 52 to channel 88 which communicates to conduit 46. When the pressure oil is connected to conduit 45, the conduit 44 is connected to drain through channel 90 suitable ports in shaft 52 and chamber 91 in piston rod 82 beneath the land 80 to the booster pump inlet channel thus establishing a drain through relief valve ll of conduit 69 for oil on the inboard low pitch side of the pitch changing piston 36. The result of admitting governor pressure fluid through conduit 46, is, as previously described, to move the piston 36 inboard, i. e., to increase the pitch of the blades 18, with a resultant decrease in revolutions per minute.

As the governor fly weights 58 slow down they permit the speeder spring 84 to depress the piston rod of valve 82 o that the land 78 closes off the pressure governor fluid passing from chamber 16 to channel 88 when the selected speed setting of the governor has been reached, hereinafter called on speed condition.

If the governor speed is substantially reduced below the selected speed setting, pressure fluid in chamber will be admitted past the land 80 to channel 90 and conduit 44 to the inboard low pitch side of piston 36 to move piston 36 toward the low pitch position, while the fluid 4 on the outboard side of piston 36 will be drained through conduit 46, channel 88, past land 18 into chamber I02 to the hollow stem of pilot valve 82 into the intake channel 10 of the governor booster pump hereinafter called underspeed condition."

A pressure relief valve 92 is provided in the governor booster pump discharge passage as is usual in this type of governor. Pressure fluid that enters fly weight housing 95 or chamber 98 that would tend to force piston rod 82 down is vented through channels mo and 94 into hollow drive shaft 52, thence into a suitable reservoir such as the engine crankcase.

The constant speed, double-acting governor as previously described in general, will now be treated in more detail to demonstrate the novel features and advantages of this invention.

The lands l8 and on pilot valve 82 are substantially the same width axially as the width axially of their adjacent ports in shaft 52. The axial spacing between lands l8 and 83] is less than the axial spacing between their respective adjacent port spacing. Consequently lands 1B and 80 cannot completely cover their respective ports simultaneously. As this invention is embodied in an actual operating governor and propeller, a differential spacing of .012 inch between lands l8 and 8t and their adjacent ports has proven successful and satisfactory.

Each of the lands is and 80 have two major sides which terminate in edges which cooperate with respective edge portions of their adjacent ports. In other words, the edge of one major side of each land will control pressure flow while the edge of the other side will control drain flow in cooperation with the cooperating edge portions of the respective adjacent port. The foregoing then applies to the terms drain and pressure controlling edges as used herein.

When the propeller and governor are in the onspeed condition (Fig. 2) land 78 will cover its adjacent port closing off channel 88 from chamber 16, maintaining pressure against the high pitch side of the pitch changing piston 36 balancing the forces in the blades (8 tending to force them to low pitch. Land 80 does not completely cover its adjacent port thus permitting fluid on the low pitch side of the pitch changing piston 36 to drain through channel into chamber 9| thence to duct "H3. The forces holding the propeller at the blade pitch necessary to maintain the predetermined speed are the forces in the blade, such as aerodynamic forces which may tend to turn the blades in either direction and centrifugal twisting moments which tend to force the blades 1 8 toward low pitch and fluid pressure on the high pitch side of the pitch changing piston 36 tending to force the blade toward high pitch and drain pressure on the low pitch side of piston 36 tending to force the blade toward low pitch. In this condition, the governor is performing as a single-acting governor.

Referring to Fig. 3, if there is any leakage of the pressure fluid from the high pitch side of the pitch changing piston or its connecting channels, passages or ports, the forces in the blades 3 tending to reduce the propeller pitch will become greater than the fluid pressure acting on piston 36 tending to increase the propeller pitch causing the blades [8 to move to a lower pitch resulting in a slight increase in revolutions per minute of the propeller and governor. The increased revolutions per minute will cause fly eig t 55 to r ise piston rod and pilot valve 82 a small amount resulting in land t8 uncovering its adjacent port permitting pressure fluid to flow from chamber 15 to flow into channel 88, 46, 48 to the high pitch side or the pitch changing piston causing it to increase the pitch of blades 38, resulting in a restoration of the propeller and governor to the selected speed set,- ting. After reachingthis onspeed condition sufii cient'iluid will continue to flow past land 1-8 intov the channel 88 to just make up for the leakage. The raising of piston rod and pilot valve 82 causes the land to to further uncover its ajd jacent port permitting fluid to continue to drain from the low pitch side of the pitch changing piston .325. The position of the pilot valve 82 and its lands 18 and as with respect to their adjacent ports under this onspeed condition when there is slight leakage is substantially the same as an overspeed condition with no leakage. The governor is still performing as a single acting governor. The forces acting .upon the pitch changing pistons 36 are the forces in the blades is tending to turn said blades l8 toward low pitch and the opposing fluid pressure acting upon the high pitch side of the pitch changing piston 35, the low pitch side of the pitch changing piston 36 open to drain.

If the power of the engine to which the pro-.-

peller is attached is decreased or flight condi tions of the airplane to which the engine and propeller are attached should alter causing the propeller revolutions per minute to increase, an overspend condition will result and a cycle of governor and propelle operation similar to that described above for slight leakage will take place so that the selected speed setting of the propeller and governor will be restored.

Referring to Fig. 4, the underspeed condition, small decreases of propeller and governor speed over the selected speed setting caused by small power decreases of the engine to which the propeller and governor are attached or varia... tions of flight conditions of the airplane to which the engine, propeller and governor are attached, will cause the speeder spring 84 to force the piston rod and pilot valve down, land is to uncover its adjacent port permitting fluid to drain from the high pitch side of the pitch changing piston 36 into chamber 92. Land at will not have moved sullicientl-y downward to cover its adjacent port, permitting fluid to drain from the low pitch side of the pitch changing piston 36. Both sides of piston 36 are now connected with drain. The only unbalanced forces acting upon the pitch changing piston 36 are those in the blades 18 tending to turn said blades Hi to low pitch. The rate of change of. pitch to low pitch is determined by the rate of fluid flow past land 13 to drain. This condition will. prevail until the propeller and governor have been returned to the selected speed settin when the fly weights 56 will balance the force of the speeder spring 8.4 and return the piston rod and pilot Valve 82 to the onspeed condition, as in Fig. 2. The governor is acting as a single-acting governor in this condition.

It has been found in practice that the speed of a propeller and governor containing this invention while operating at a constant speed setting and: attached to an airplane operating under normal conditions of level flight generally will vary not more than 0.2 of 1% of the selectedspeed setting. During most conditions of turbulent Weather, the variation generally will not exceed If the power of the engine to which the pro peller and governor are attached is substantially decreased or the airplane to which the engine,

propeller and governor are attached is caused to enter a climb attitude, the propeller and gov.- ernor speed will be reduced considerably below the selected. speed setting. Referring to Figs; 1 and 5, this considerable reductionmajor underspeed-will cause the speeder spring 84 to move the piston rod and pilot valve 82 down to a position where land 30 uncovers its adjacent port permitting pressure fluid to flow from chamber 15 to channel .99, 44, chamber 48 to the lowpitch side of the pitch control piston 36, cansing the pitch of blades to be reduced. Land 18 has uncovered its adjacent port permitting fluid to drain from the high pitch side of the pitch changing piston .36 through channel 88 intochamber W2. The governor pressure fluid exerting force on the low pitch side of the pitch changins piston 36 assists the centrifugal twisting moment in reducing the pitch of blades I58, restoring the propeller and governor speed to the selected speed setting more rapidly. The governor is acting as a double-acting governor in the condition described immediately above.

The improved governor pilot valve which is the subject of this invention embodying lands axially spaced differentially from the axial spacing of the ports adjacent said lands gives a greater sensitivity to speed changes imposed upon the governor than a governor pilot valve in which the axial spacing of the lands is identical with the axial spacing of ports adjacent said lands as formerly incorporated in double-acting governors as applied to aeronautical propellers of the type previously described. 7

In a governor pilot valve having lands and adjacent ports axially identically spaced, two different hydraulic centering forces act upon the valve tending to cause it to move to' a position of closing off both ports before the governor has reached the selected speed setting and balance between the fly weights and opposing spring forces. The action of the hydraulic centering forces that tends to close the ports at small openings reduces the sensitivity of the governor to small changes of speed. Test results of a propeller-governor combination show the non-effective range generally to be plus or minus 10 R. P. M.

Referring to Fig. 3, pressure fluid in chamber 16- will flow past land 18 into channel 38 with a velocity causing a reducedpressure immediately below the under face of land 73 according to" Bernoullis theorem. The fluid pressure acting upon the upper face of land 88 being static will be greater than that acting upon the under face or land '18 thus tending to force the pilot valve 82 downward closing off the port prematurely.

A- similar: hydraulic centering forcewill occur in cavity SH with a' greater fluid pressure acting upon the upper face of land H36- than on the under face of la-nd so because of the velocity past 181K180;-

Withlands and adjacentports identically axi ally spaced, the aforementioned hydraulic centering forces will cooperate to give a combined force that is approximately twice the intensity of the individual force. With lands and adjacent ports difierentially axially spaced, one hydraulic centering force is eliminated by virtue of one port Opening being sufliciently large to reduce the orifice efiect to a negligible quantity. Test results of the previously mentioned propeller-governor combination indicate that the elimination of one hydraulic centering force reduces the non-effective range of the governor by half, i. e., to plus or minus R. P. M.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims,

I claim: Y

" 1. In combination with a controllable-pitch propeller having a double-acting hydraulicallyactuated pitch changing device and having blades continuously urged in one pitch changing direction, a governor comprising speed responsive means and a control valve having a spooltype element movable thereby, said valve having two permanently spaced ports connected with opposite sides of said propeller actuating m ans and two permanently spaced lands carried by said element and controlling said ports, each of said lands being of substantially the same width as the port with which it cooperates, said ports and lands being relatively movable, a pressure connection and a drain connection, one of said connections permanently opening between said lands and the other of said connections permanently opening on the other sides of said lands, said ports being spaced differently than said lands, the difference in said spacing being less than the width of said ports and lands whereby both of said ports are simultaneously opened to said drain by said lands when both said ports are blocked by said lands from the pressure connection.

2. In combination with a controllable-pitch propeller having a double-acting hydraulicallyactuated pitch changing motor, and'having blades continuously resiliently urged in one pitch changing direction, a governor comprising a control valve and speed responsive means for operating said valve, said valve comprising cooperating relatively movable ports and lands of substantially the same width, each land having two major sides terminating in edges which respectively control pressure and drain fluid in cooperation with the adjacent edge portion of its respective port, said lands being permanently spaced from each other a predetermined distance difiering from the port spacing by an amount less than the width of each of said ports, said valve having a pressure connection and a drain connection, one of said ports being connected with one side of said double-acting pitch changing motor and selectively connectable by said valve with either said pressure or said drain connection, the other of said ports being connected with the other side of said motor and selectively connectable by said valve with either said drain or said pressure connection, one of said pressure and drain connections permanently opening between said lands and the other of said connections permanently opening on the other sides of said lands, the drain controlling edges of said lands being closer to said pressure connection 8. for 'the respective land than the corresponding drain controlling edges of said ports, and the pressure controlling edges of said ports being spaced at least as far from the pressure connection for the respective port as the corresponding pressure edges of said lands.

3. In combination With a controllable-pitch propeller having a double-acting hydraulicallyactuated pitch changing motor, and having blades continuously resiliently urged in one pitch changing direction, a governor comprising a control valve and speed responsive means for operating said valve, said valve comprising cooperating relatively movable ports and lands of substantially the same width, each land and its cooperating port having cooperating drain controlling edges, said ports being permanently spaced from each other a predetermined distance, said lands being permanently spaced from eachother a predetermined distance difiering from the port spacing by an amount less than the width of each of said ports, said valve having a pressure connection and a drain connection, one of said ports being connected with one side of said double-acting pitch changing motor and selectively connectable by said valve with either said pressure or said drain connection, the other of said ports being connected with the other side of said motor and selectively connectable by said valve with either said drain or said pressure connection, one of said pressure and drain connections permanently opening between said lands and the other of said connections permanently opening on the other sides of said lands, the drain controlling edges of said lands being closer to said pressure connection for the respective land than the corresponding drain controlling edges of said ports so that the port connected with the side of the pitch changing motor opposing movement of the propeller blades in said one direction may be connected with either pressure or drain while the other side remains connected with drain.

4. In combination with a controllable pitch propeller having a double-acting hydraulicallyactuated pitch changing motor, and having blades continuously resiliently urged in a pitch reducing direction, a governor comprising a control Valve and speed-responsive means for operating said valve and controlling said propeller, said valve comprising relatively movable cooperating ports and lands, said ports being spaced from each other at predetermined distance and said lands being spaced from each other a predetermined distance differing from said port spacing by an amount less than the width of each of said ports, said valve having a pressure connection and a drain connection, one of said ports being connected with one side of said double-acting pitch changing motor and selectively connectable by said valve with either said pressure or said drain connection, the other of said ports being connected to the other side of said doubleacting pitch changing motor and selectively connectable by said valve with either said drain or said pressure connection, one of said connections permanently opening between said lands and the other of said connection permanently opening on the other sides of said lands, said lands being closer to said pressure connection for the respective land than said ports so that the pitch increasing side of said motor may be selectively connected with pressure or drain while the pitch reducing side of said motor is connected with drain whereby the governor and propeller may act as single acting devices for sma11 speed variations but may act as double acting devices for greater speed variations.

CHESTER M. JEDRZIEWSKI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Baker et a1 June 12, 1900 Johnson Sept. 12, 1905 Lower Mar. 13, 1917 Caldwell et a1. Oct. 3, 1938 Overbeke July 30, 1940 Martin Nov. 25, 1941 Number Number

Images