US2715891A - Hydraulic governor compensating system - Google Patents

Description

Aug. 23, 1955 A. H. RODECK ETAL 2,715,891

HYDRAULIC GOVERNOR COMPENSATING SYSTEM Original Filed Sept. 10, 1948 INVENTORS ARM/N RoDEcK ancg fu BERT 6. MASSEY ATTORNEYS.

United States Patent Ofi ice 2 ,7 l 5,8 9 l Patented Aug. 23, 1955 HYDRAULIC oovEnNoR COMPENSATING SYSTEM Armin H. Rodeck and Albert G. Massey, Watertown,

N. Y., assignors to, Massey Machine Company, Watertown,N.Y.

Original application September 10, 1948, Serial No. 48,733, new Patent No. 2,623,564, dated December 31 1952. Divided and this application October 27, 1952, Serial N 0. 317,062

6 Claims. ((11. 12142) This invention relates to hydraulic governors for speed control and similar adaptations. This application is a division of our application, Serial No. 48,733, filed September 10, 1948, now Patent No. 2,623,504, dated December 30, 1952.

The principles of the present invention are applicable to direct-acting hydraulic governors of the, general class shown in our prior co-pending application, Serial No. 7l9,682, filed January 2, 1947, now Patent No. 2,516,723. in the aforesaid application, the governor is rendered selfcornpensating by providing that the application of corrective fluid pressure to the power piston is pulsating or intermittent, so that during governor adjustment the movement of the power piston is by small steps or increments to avoid overshooting. The principles of the present invention provide essentially another compensating system whereby the pulsating pressure method may be eliminated; but in its broadest aspect, the present invention also comprises an improvement in the operation of the pulsating fluid pressure method of compensation.

In one form of the present invention, a fluid pressure chamber is established which is compressed or expanded directly by operation of the pilot valve, and a compensating cylinder in constant communication therewith has a compensating piston directly connected with the power piston for movement therewith. The compensating system thus established comprises normally a closed fluid system save only for a leakage needle valve or similar adjustably reduced orifice which acts as a dashpot regulator directly upon the pilot valve in resistance to initial movement thereof.

Secondly, the needle valve acts as a bypass to. propor-. tion the rate of time at which compensating fluid will act to close the pilot valve and thus proportions the degree of corrective movement of the power piston upon displacement of the pilot valve. Thirdly, the needle valve times the speed with which the pilot valve moves back to neutral in proportion to the speed of response of the engine so that the pilot valve will not move to open in the opposite direction under the pressure developed by the compensating piston.

In one aspect the principles of the present invention are applicable to the pulsating fluid compensating system and in this case the fluid chamber which is directly compressed and expanded by movement of the pilot valve has direct connection only with the needle valve controlled orifice, so that it comprises a dashpot cooperating directly with the pilot valve upon movement thereof from normal neutral position.

The present invention further provides means acting in cooperation with the pilot valve fluid chamber and the compensating fluid chamber to provide surge chambers both to serve as pressure accumulators and to serve as proportioning devices to determine the degree of initial corrective movement to be made by the power piston in response to pilot valve displacement. The accumulator and proportioning surge chambers may be used in com-.

bination or either one separately in conjunction with the aforesaid compensating system, and in modified form the same chamber may be employed to serve both purposes.

The present invention further provides means which nullify the compensating system upon extreme speed changes, so that a stronger compensating system may be employed to compensate for speed changes less than the established extremes. I

Various other aspects of novelty are referred to and pointed out in detail in the following detailed specification, taken in conjunction with the accompanying drawings. It is to be understood that the principles of the present invention are not limited to the precise form set forth by way of example, but only as defined in the appended claims.

The single figure of the drawing is a general schematic view of one form of the governor of the present invention.

In the form of governor illustrated in the drawing, the numeral 10 designates a shaft which is connectible with the engine or other device or system to be governed. The purpose and effect of the governor system is to maintain a constant velocity of shaft 10 despite changes in load, in the case of an engine, or of other conditions tending to vary the velocity of shaft 10. In the alternative, the governor serves to maintain a constant degree of speed droop, that is, a predetermined lessening of velocity with increases in load. The form of governor illustrated herein may be provided with speed droop ad,- justing means such as are shown in our co-pending appli cation Serial No. 403,581, filed on November 3,0, 195.3 and which is a division of now abandoned application Serial No. 46,098, filed August 25, 1948.

Adjustment of the engine or other device or system being governed is accomplished by rotating or oscillating a shaft designated 11 in the drawing, and in the case of an engine shaft 11 may be connected with the throttle valve or other fuel control means, as by means of an arm 12. In the case of engine governing operation the load on the engine is reflected in the angular setting of shaft 11.

The flyweight head and the hydraulic fluid system which cooperates therewith operates in a housing 14 and comprises a shaft or sleeve 15 which rotates in a suitable bore in housing 14 and, in the present instance, is fixed directly to. shaft 10. and may comprise. an extension there: of, the shaft 19 being driven by the engine being gove. erned.

Shaft 15 is bored to receive a pilot valve 16 which has axially spaced generally cylindrical valve heads 17. and 18 and is formed at its upper end with an enlargement 19 which cooperates to support a plurality of flyweights; 20 The flyweights 20 are carried by arms 21 which have a common pivot 22 at the outside of shaft 15. The arms 21 are pivotally engaged by links 23- which are. also pivotally connected to the enlargement 19 of pilot valve 16 as at 24.

From the foregoing it will be clear that any tendency of centrifugal force to move the flyweights outwardly, upon increase in speed of the shafts 10- and 15, tends to. straighten the toggles which the arms 21 and the links 23 form, and this results in lowering movement of pilot valve id in the bore of the shaft 15. A decrease in speed, evidenced by a tendency of the fly weigh-ts, to move inwardly toward the shaft 15, tends to collapse the toggles, and the links 23 accordingly raise the pilot valve 16 in the. shaft 15. The, pilot valve 16 rotates with shaft 1 5 bnt is free to move axially therein.

The necessary hydraulic pressure required, for opera,- tion of the governor is provided by a pump indicated at 25, which may be arranged to be driven from shaft 1Q by a pair ge r 27 n 2 e pu p 25. s p ef r ly of the reversible type wherein the output is unidirectional regardless of the direction of rotation ofthe pump'drive means. The outlet side of pump 25 communicates, by means of .a conduit 30, with an annular passage 31 .formed in support 14 and extending about 'shaft 15,. the v latter having a series of peripheral openings 32 in shaft 15, whereby 'conduit'3t) hascontinuous and uninterrupted communication with the space between valve heads 17 and 18.

V The housing 14 has a pair of passages 37 and 38, and shaft 15 is provided with peripheral openings 39 and 40 which are normally axially in registry with'the valve compensating cylinder chamber 68. A second passage heads 17 and 18and'also register axially with the passages 37 and 38 of housing 14, as illustrated in 'Fig. l.

i is disposed in chamber 43 and has a piston rod 45 which connects with an arm46 fixed to shaft 11. In this way axial movementof piston 44 in chamber 43 produces rotative movement of shaft 11 and thus the movements of piston 44 in cylinder 43 directly determine and reflect the load setting of shaft 11, or any other variable condition which shaft 11 may serveto adjust. V

Shaft 15 is formed with a peripheral outlet passage 50 above the upper valve head17 and a second peripheral outlet passage.51 below valve head 18. The upper outlet passage 50 is in continuous communication with the general interior of a casing 53 in which the governor is enclosed, and the lower'outlet passage 51 is provided with a peripheral groove 55 formed in shaft 15 so that outlet opening 51 has .continuous communication with 7 an outlet passage 56 formed in housing 14.

. At its upper end enlargement 19 of pilot valve 16 connects with'the lower end of an extension coil spring 57 whose upper end is shown connected to the interior of housing 53 by means of an anti-friction bearing swivel In a general way, it will be seen from the foregoing that acceleration" of shaft 10, by reason of increased centrifugal force on flyweights' 20, will lower pilot valve 16 and, by lowering, of valve head 18, connect pressure supply conduit 30awith conduit 38." This directs fluid pressure against the lower side' of piston 44 and accord- V 'ingly rotates shaft 11 in a counterclockwise direction to decrease the fuel setting, in instances where an engine is being governed, to accomplish the necessary slowing of shaft 10 to its desired speed level. v

At the same time that conduit 38 is connected with fluid pressure supply conduit 30, conduit 37 is connected with outlet passage 50 by reason of the lowering of valve head 17; The casing 53 which houses 'the governor mechanism itself comprises. a reservoir or sump for pump and all of the discharge outlets of the system discharge into the interiorof casing 53 where they gravitate to the sump for reuse by the pump. In the form of governor illustrated herein, the level of oil in'the casing 53 is maintained substantially at or above the level 7 indicated at 60 for purposes which will appear later Shaft .15 is formed with a passage 69 leading from fluid pressure chamber 62 and has a peripheral groove 70 which places passage 69 in continuous fluid communication with a passage 71 in housing 14 which leads to 73 formed in housing 14 leads from compensating cylinder 68 and comprises an outlet orifice adjustably restricted by means of a screw threaded needle valve 75.

With so much of the system as has thus far been described pilot piston chamber 62 and compensating cylinder 63 are in free and continuous communication and their only external communication is byway'of passage 73, under the restrictive control of needle valve 75. It

isto be noted that the outer end of passage 73 is con-. tinuously submerged in the hydraulic medium 60 in cas ing 73.

As thus arranged the pilot piston chamber 62 and compensating cylinder 68 act as compensating means' particularly adaptable to slow speed engines with'heavy, flywheels and proportionately slow response. gree of response of the governor to a change in engine speed can be-reduced to any desired speed of correction by adjustment of needle valve 75.

If. the load on'the engine being governedis reduced, its

speed tends to increase and the consequent outward urge of flyweights 20 moves pilot valve 16 downward. This movement is resisted by the fluid under piston head 61 in chamber. 62, its only mode of egress being past the restricted orifice in passage 73 formed by needle valve In additionto this fluid resistance, downward move- 75. ment of the pilot valve connects pressure from conduit 30 to the underside of power piston 44, causing upward 'movement of compensating piston 66 and consequent forced fluid flow from compensating cylinder 68.

Again because of .the restriction interposed by needle.

approaching its initial speed because of the amount of adjustment imparted to rock shaft 11' by'movement of power piston 44, has not gone down to initial speed;

During this period the pilot valve is pushing down on the compensating fluid in chamber 62 with a force corresponding to'the amount that'the'engine is off speed, and

this force causes leakage past the needle valve while the engine is coming back to speed, the speed of such leakage beingt suflicient to prevent the pilot valve from moving away. from neutral in the opposite direction; v

If, the throttle adjustment effected by the power piston 44in the foregoingmanner proves insufficient, the pilot valve again moves downwardly to further adjust the power.

piston, such further, adjustment being of, lesser degree than the vfirst because the engine has partially returned to proper speed and therelative unbalance of the flyweight force-is correspondingly less.

Upon an increase in load on the engine, a rvetsegovernor operation takes place. The pilot valve 16 rises and power piston 44 moves downwardly; This tends to enlarge both the chamber 62 beneath pilot valve 16 and the j compensating. cylinder 68. Thus, flow of fluid in passage 73 is from outside of housing 14 into. the compensating cylinder 68, the outlet end of passage 73 being submerged in hydraulic medium as heretofore described. The operation is otherwise the same in theory as upon reduction in load on the engine. 7

It will be noted from a study of the foregoing that the restricted orifice controlled by needle valve 75 serves a three-fold function. First, itacts as a dashpot to regulate the initial pilot valve-movement upon a deviation in speed of the'engine being governed. Second, it serves as a by-pass to regulate the time period which will. elapse before compensating fluid from compensating cylinder 68 The de-' The needle valve thus acts as;

will raise the pilot valve 16 to neutral position and thus proportions the degree of governing movement of the power piston. Third, it serves as a time delay means during the period when the pilot valve is in neutral and motionless while the engine is responding to the completed adjustment of the power piston 44, preventing the pilot valve from opening in the opposite direction.

It will be noted that with the foregoing compensating arrangement no other or extraneous compensating provision need be made, such as the continuously interrupted flow of fluid from the pilot valve shown and described in our two prior applications identified above. In the form of the present invention illustrated herein, grooves 41 and 42 in shaft provide for continuous and uninterrupted flow between pressure supply conduit and either of the passages 37 or 38 when the pilot valve 16 is displaced in one direction or another.

The system thus far described is complete and operative, and the additional appurtenances now to be described constitute, in effect, additional modifications of the principles of the present invention. Referring to the drawing, the numeral designates a cylindrical surge chamber which serves as an accumulator. A piston 81 is provided in chamber 36 and a relatively stifl compression-extension coil spring 32 is fixedly secured at its opposite ends to piston 81 and to the bottom of chamber 80. The accumulator chamber above piston 81 connects with passage 71 as at 83.

The push-pull action of spring 82 causes chamber 89 to serve as an accumulator in either direction, positively or negatively, from the neutral position where spring 82 is unstressed. This accumulator will be employed with engines that respond more quickly than those previously considered herein. In the case of modern higher speed engines having quick response to throttle changes there is less tendency for the governor to operate too fast and cause hunting.

The presence of the accumulator in such applications imparts greater flexibility of operation and the more yieldable nature of the forces imposed on the pilot valve by the compensating system gives the pilot valve more flexibility in producing control changes in the position of the power piston.

A further modification of the basic disclosure comprises a pressure conduit 90 from pressure supply conduit 36 to. housing 14 where it communicates with groove 70 and accordingly with the interior of chamber 62. This maintains a positive hydro-dynamic fluid pressure force under pilot valve 16. in partial counterbalance to the flyweight force, and there is a continuous flow outwardly past needle valve 75.

The degree of pressure normally maintained beneath pilot valve 16 in this manner may be manually adjusted by means of a valve 91. Thus, the movement of the compensating piston in this form modifies the pressure normally present under the pilot valve, either by increasing or reducing the same, during a governing step. Pressure conduit 90 may be used either with or without the accumulator arrangement 30 through 83.

It will be noted that piston head 61 of pilot valve 16 has a fluid passage 91 leading upwardly from chamber 62 and terminating in a pair of vertically spaced horizontal passages 92 and 93 which emerge from the periphery of piston head 61. A passage 94 in shaft 15 normally lies between passages 92 and 93 and an external annular groove 95 in shaft 15 places passage 94 in continuous communication with an outlet passage 96 in housing 14.

Passages 91 through 96 are normally inoperative, even during normal governor correcting operations, since the normal displacements of pilot valve 16 are not of suflicient degree to move either passage 92 or 93 into communication with passage 94. However, upon extreme movement of the flyweights in either direction the upper passage 92 or the lower passage 93 of piston head 63 connects with passage 94 and the compensation system ineluding chamber 62 and compensating cylinder 68 may drain therethrough and; thus there is no compensating action in the case of extreme speed changes and the governor exerts a very rapid corrective action. As soon as. speed is corrected sufficiently to. move the pilot valve from either of its extreme positions, the drain connection is again broken and compensation again takes places.

With the above provision for temporarily nullifying the compensating system the compensation can be very strong for stability in normal regulation. With an engine which is slow in response or where the drive to the governoris. rough and uneven the governor must be held in restraint with a strong compensating system during normal regulating operation to prevent jiggle or hunting duri g correction.

What is claimed is:

l. A hydraulic governor comprising a hydraulic pressure operated regulator member, a source of operating fluid pressure therefor, a pilot valve movable, in opposite direction to connect said fluid pressure source to move said regulator member in opposite directions, a fluid pressure chamber and a piston movable directly with said pilot valve for compressing and expanding said chamber upon movement of the pilot valve in opposite directions, a compensating chamber and a piston movable directly with said regulator member for compressing and expanding said compensating chamber upon movement of the regulating member in opposite directions, said two chambers being in continuous fluid communication, and an adjustable leakage orifice leading from the fluid system including said two chambers to a source of fluid under substantially no pressure, said two pistons being arranged to jointly compress their chambers upon movement of the pilot valve in one direction and to jointly expand their chambers upon movement of the pilot valve in the opposite direction.

2-. A hydraulic governor comprising a pressure chamber and a regulator movable therein in response to differential pressure, fluid passage means communicating with the pressure chamber, a rotary member and a bearing support therefor, a pilot valve movable axially in said support in response to changes in speed in the rotary member, an opening in said rotary member and means on said pilot valve normally blocking said opening, speed responsive means actuable by said rotary member for controlling axial movements of said pilot valve, said fluid passage means leading to said rotary member in axial registry with said opening whereby upon displacement of the pilot valve to. expose said opening fluid pressure is transmitted to the pressure chamber, a fluid pressure chamber in said rotary member and a piston fixed to said pilot valve and operable to compress and ex pand said chamber upon displacement of the pilot valve in opposite directions, a compensating fluid pressure chamber and a piston therein fixed for movement with said regulator for compressing and expanding said compensating chamber upon movement of the regulator in opposite directions, said second mentioned fluid chamber and said compensating chamber being in free fluid communication, and an adjustable outlet orifice leading from the system including the second mentioned fluid chamber and the compensating chamber to a fluid reservoir, said two pistons being arranged to jointly compress their chambers upon movement of the pilot valve in one direction and to jointly expand their chambers upon movement of the pilot valve in the opposite direction.

3. A hydraulic governor comprising a hydraulic pressure operated regulator member, a source of operating fluid pressure therefor, a pilot valve movable in opposite direction to connect said fluid pressure source to move said regulator member in opposite directions, a fluid pressure chamber and a piston movable directly with said pilot valve for compressing and expanding said chamber upon movement of the pilot valve in opposite directions,

a compensating chamber and a piston movable directly with said regulator member for compressing and expanding said compensating chamber upon movement of the regulating memberin opposite directions, said two chambers being in continuous fluid communication, an adjustable leakageorifice leading from the fluid system includingsaid two chambers to a source of fluid under l substantially no pressure, said two pistons being arranged to jointly compress their chambers upon movement of the pilot valve in one direction and to jointly'expand their chambers upon movement of the pilot valve in the opposite direction, and an accumulator chamber in free fluid communication with said fluid system having a piston therein and resilient means for urging the'piston to'a neutral position, said piston being movable in opposite directions in response to pressure changes in said .fluid system.

' 4; A hydraulic governor comprising a pressure chamber and a regulator movable therein in response to diiferential pressure, fluid passage means communicating with the pressure chamber, a rotary member and a bearing support therefor, a pilot valve movable axially in said support in response to changes in speed in the rotary member, an openingin said rotary member'and means on said pilot valve normally blocking said opening, speed responsive means actuable by said rotary member for controlling axial movements of said pilot valve, said fluid passage means leading to said rotary member in axial registry with said opening whereby upon displacementof the pilot valve to expose said opening fluid pres sure is transmitted to thepressure chamber, a fluid pressure chamber in said rotary member and a. piston fixed to said pilot valve and operable to compress and expand said chamber upon displacement of thepilot valve in opposite directions, a compensating fluid pressure chamber and a piston therein fixed 'for movement with said regulator for compressing and expanding said compensating chamber uponzmovement of the regulator in opposite directions, said second mentioned fluid chamber and said compensating chamber being in free fluid communication, an adjustable outlet orifice leading from the system including the second mentioned fluid chamber and the compensating chamber to a fluid reservoir, said two pistons being arranged" to jointly compress their chambers upon movement of the pilot valve in one di- 4 rection and to jointly expand their chambers upon move- 'ment of the pilot valve in the opposite direction, and

an accumulator chamber in free fluid communication with said fluid system having a piston therein and resilient means for urging'the piston to a neutral position, r

said piston being movable in opposite directions in response to pressure changes in said fluid systems.

5. A hydraulic governor comprising a casing containing'a hydraulic pressure operated regulator member, a source of operating fluid pressure therefor, a pilot valve movable in opposite direction to connect said fluid presbeing in free fluid communication, an adjustable outlet sure source to move said regulator member in opposite directions, a fluid pressure chamber and a piston movable directly with said pilot valve for compressing or expanding said chamber uponpilot valve movement, a compensatmg chamber and a piston movable directly with said regulator member for compressing and expanding said compensating charnber upon movement of the regulating member, a fluid passage establishing continuous fluid communication between said two chambers, an adjustable leakage orifice leading fromthe fluid system including said two chambers to a source of fluid under substantiallyno pressure, andfluid passage means in the pilot valve pistonleading from the first mentioned fluid chamber and operable to vent said fluid system when thepilot valve approaches either of its extreme positions due to an unusual load change. I

6. A hydraulic governor comprising a pressure chamber and a regulator movable therein in response to diiferential pressure, fluid passage means communicating with the pressure chamber, a rotary member'and a bearing support therefor, a pilot valve movable axially in said support in response to changes in speed inthe rotary member, an

opening in said rotary member and means on said pilot valve normally blocking said opening, speed responsive means actuable by said rotary member for controlling axial movements of said pilot valve, said fluid passage fixed for movement With said regulator for compressing and expanding said compensating chamber upon movement of the regulator in opposite directions, said second mentioned fluid member and said compensating chamber orifice leading from the system including the second mentioned fluid chamber'and the compensating chamber to a fluid reservoir, and fluid passage means in the pilot valve piston leading from the second mentioned fluid chamber and operable to vent said fluidsystem when the speed responsive means moves the pilot valve beyond a predetermined degree due to an abrupt change in speed.

' References Cited in the file of this 'patent V UNITED STATES PATENTS 1,106,434 Woodward Aug. 11, 1914 2,219,229 Kalin n Oct. 22, 1940 2,333,184 Kalin Nov. 2, 1943 2,478,183 Drake Aug. 9, 1949 2 2,623,504 Rodeck et a1. Dec. 30, 1952

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