US3011352A - Hydraulic governors - Google Patents

Description

Dec. 5, 1961 L. J. MOULTQN ETAL 3,011,352

HYDRAULIC GOVERNORS Filed April 21, 1958 INVENTORS L. J. Moo/Jaw 11d BnxTE Q.

HTTOR/VELV atent 3,011,352 Patented Dec. 5, 1961 fiice 3,011,352 HYDRAULIC GOVERNORS Lloyd .Iackson Moulton, Mentor, and Donald J. Baxter,

South Euclid, Ohio, assignors to Curtiss-Wright Corporation, a corporation of Delaware Filed Apr. 21, 1958, Ser. No. 729,639 4 Claims. (Cl. 73523) This invention relates to a hydraulic governor or automatic speed regulator mechanism for engines and/or other machines having rotary parts, the objects including provisions of a new or improved hydraulically operating governor having a so-called compensating or temporary speed reset or speed droop system or mechanism for attaining isochronous governor operation; a simple and effective adjustable permanent type speed reset mechanism enab ing the basically isochronous hydraulic governor to operate with various readily selectable amounts or percentages of speed droop; a hydraulic governor unit having either or both the above types of speed reset mechanisms capable of being made for efiicient operation in extremely small size and so arranged that the unit can operate in any desired position on an engine or other machine with all working parts of the governor submerged in governor oil at relatively low and controlled pressure.

The herewith illustrated embodiment of the invention is a governor unit similar to those shown by A. Kalin US. patent, Reissue 23,994 dated May 3, 1955; A. H. Rodeck and A. G. Massey U.S. Patent 2,623,504 issued December 30, 1952, and B. O. Burritt US. Patent 2,560- 758 issued July 17, 1951. In each of thosepatents primary compensation action on the speed sensing mechanism is a function of governor servo or power piston movement and secondary compensation action is, in effect, dissipation of the servo-applied compensation force at a variable or adjusted rate. In such governors it is desirable that friction forces on the speed sensing mechanism and the movable parts involved in the compensation action be minimized as much as possible. In the Kalin and Rodeck et al. governors, compensating oil in a generally closed system isolated from that of the governor servo mechanism and its pilot valve control acts directly upon a receiving piston portion of the governor pilot valve, and a yieldably positioned feedback force storing piston, hereinafter usually called a proportioner piston, is subjected to compensating fluid pressure during speed error and which incidentally prevents fluid temporarily trapped in the compensating fluid passage from opposing free movement of the pilot valve. The proportioner piston is normally held in a neutral or freely floating equilibrium position by a helical spring. It is important that'the proportioner piston and its positioning spring be made readily accessible for inspection or change of spring force. It is of greater importance that the proportioner piston as Well as the governor pilot valve and its receiving piston portion shall be as free from static friction as possible; and a high degree of freedom is obtained by maintaining continuous relative rotation of mating cylindrical surfaces of the parts. The present invention, as its principal novel features, provides a readily accessible postion for the proportioner piston as wellas a simple and novel means to obtain continuous relative rotation of it in reference to its coacting cylinder, without requirement of appreciably more cost than is necessarily involved in an effectual arrangement for driving the governor ballhead or speed sensing flyweight mechanism while permitting the ballhead speed to be altered inreference to the governor driv shaft speed.

In making the present governor in as compact form as sometimes required for installation and operation on small engines, the governor case is provided for isochronous operation, with a simple low height sealed cover for the main governor ease, and when it is desired to adapt such normally isochronous governor for permanent but adjustable speed droop operation, this cover is replaced by a different sealed cover arrangement having the principal components of the permanent speed droop mechanism mounted unitarily therewith and so as to be readily removable from the governor case Without disturbing any other portions of the governor mechanism.

Various objects and novel features of the invention not indicated by the above discussion will become apparent from the following description of the herewith-illustrated embodiment. The essential characteristics are summarized in the claims.

In the drawing, FIG. 1 is a schematic view showing the preferred arrangement of hydraulically operated parts and associated fluid connections. FIG. 2 is a plan view of a physical embodiment of the governor, a detachable cover of the main case having been removed to expose the principal rotary parts and others. FIG. 3 is a longitudinal sectional assembly view taken as indicated'by the line 33 on FIG. 2. The members shown at the top of FIG. 3 (above terminal shaft K) are shown broken away along the section indicating line 3a on FIG. 2 (complementing the leftward portion only of line 3-3). FIG. 4 is a fragmentary sectional detail view taken at line 44 on FIG. 2 and showing the preferred governor ballhead drive and an important part of the compensating system. FIG. 5 is a detail sectional view of the preferred permanent speed droop mechanism, taken along the lines 5-5 on FIG. 3. FIG. 6 is a detail showing a modified needle valve mounting.

The hydraulic governor mechanism generally as shown in FIGS. 1 and/or 3 includes a suitably sealed casing A containing a rotary engine speed error detector mechanism B with flyweights B; a speeder spring C, settable for desired engine speed as by a speeder lever (33, FIG. 3) and connected Speeder plug C; and a pilot valve or valve mechanism D, the movable element of which, as shown, is a rotatable valve plunger E in a non-rotating or fixed valve sleeve E. The pilot valve- D controls the operating effect of approximately constant pressure fluid (governor oil as supplied by the engine lubricating system or by a governor-case-controlled pump, not shown, admitted to passage F) on a differential area type servo mechanism G, represented by lever-connected power pistons G and G" and their respective cylinders H and H.

The pistons G and G" act relatively oppositely on governor output or terminal rockshaft K, through unequal length arms of a lever L, as shown, and stiff rods or links L and L" which are self-centering in tapered sockets of respective pistons. Supply pressure passage F is continuously connected to cylinder H of servomotor piston G, and movements of the pilot valve determine the direction of operation of the terminal shaft K by controlling admission of pressure fluid to cylinder H and spill offluid therefrom.

In the illustrated equilibrium or neutral position of the pilot valve plunger E, oil is trapped, via passage 3', in contact with power piston G". That piston, as shown in FIGS. 1 and 2, has a larger diameter than piston G and that difference, in conjunction with a calculated relatively longer lever connection to terminal shaft K than piston G has, enables single-port-control pilot valve action to produce two-way movement of the terminal shaft K with approximately equal torque in the two directions.

In operation, to cause increased engine fuel metering movements of the terminal shaft K (counterclockwise in FIGS. 1 and 3), the pilot valve plunger E (by lowering as in response to diminished engine speed) admits governor oil through passage I to the relatively larger diameter cylinder H; and to cause decreased engine fuel movements of the terminal shaft K the pilot valve plunger E J is moved upwardly to spill trapped oil from the cylinder H to sump, as through a port S of the pilot valve sleeve.

In FIG, 1, the hydraulically acting temporary speed droop or compensation system between the power piston mechanism G and the speed sensitive mechanism B is diagrammatically represented by an actuating displacement pump N operated by the power piston mechanism G; generally isolated compensation oil passage or duct receiving piston portion P of the pilot valve plunger E; yieldably supported and normally stationary proportioner piston P exposed to pressure in passage 0, and a needle valve R for reset rate or timing leak-01f adjustment as required to accommodate the rate of engine response to the amounts of fuel correction as well known in the art.

As shown in FIGS. 1, 3 and others, the governor housing or case comprises a base section 10, main power case and speeder section 11 and a cover 12 (or 12, cf. FIGS. 3 and 4) constituting a fully sealed container for fluid which may fill the entire case and be suitably regulated to have a uniform but preferably relatively low pressure. Thereby the governor may be operated in any desired position other than vertically or as illustrated. A governor drive shaft 14, FIG. 3, coaxial with the pilot valve mechanism, extends through a suitable bearing bore in the base section and is rigid or integral with a gear 15 in a cavity in the base section covered by the lower face of main section 11. The gear 15, as shown by comparison of FIGS. 1, 3 and 4, meshes with a gear 17 in the base section 10 and which, as shown in FIG. 4, has a generally cylindrical tubular hub or quill portion 18 extending vertically in a guide bore 18 of case section 11 and carrying a gear 20 rigid therewith, as on splines, not shown, for ready removability (e.g. in event it is desired to change ballhead driving speed). The gear 20, as shown in FIG. 4, is retained in position on the tubular hub 18 by a snap ring 20 and meshes with a complementary gear 21 rigid with a rotary ballhead assembly or unit 22 which includes gear 21. Unit 22 is readily removably supported on a stepped diameter journal formation 21' at the top end of the fixed or non-rotatable valve sleeve E.

The flyweights B, FIGS. 1 and 3, are preferably supported by the ballhead unit 22 on leaf springs 25 suitably secured to a base portion of unit 22 at their lower ends; and the outward and inward radial movement of the flyweights is transmitted to the pilot valve plunger B through a U-shaped single piece leaf spring 26 secured tightly to the flyweights and extending under a generally rounded surface of a bearing-supporting cup member 28 fastened to the top end of the valve plunger E as by a screw 29. The lower support or perch member 30 for the speeder spring C is held against rotation by the speeder spring and itsspeeder plug C, and an anti-friction hearing assembly 32 is interposed between the perch 30 and the cup 28.

Speed setting or speeder lever 33 is pivotally supportedorder that the speed adjusting screw 36 can be readily attached to and detached from the associated free end portion of the lever 33 as a function of movement of the cover into and out of the illustrated position, a reduced diameter lower end portion 36 of the screw enters an open slot 38 (FIG. 2) in the lever. The speeder spring holds the lever against a shoulder near the lower end of the screw 36. Speed droop mechanism 40, when provided in the governor as will be described, operates on the speed setting lever pivot 3-4 to modify the set speed as a function of servo piston position in a generally well known manner. All parts which extend through the walls of the case A generally are suitably sealed against leakage.

Referring further to the governor compensation system as shown by comparison of FIGS. 1 and 4, the actuating compensation fluid pumpN can be made similarly to the pistons and cylinders of servo or power piston mechanism G, the pump N being shown as a piston 40a connected as by a rigid link in the form of a rod 41 to the lever L, the rod having its lower end received in a suitable centering socket in the piston. Piston 40a of the actuator pump N has a return spring 42 for upward stroke movement or in the fuel decreasing direction of the terminal shaft K. When the terminal shaft is removed from the casing section 11, the operating rods L and L of pistons G, G and rod 41 can be lifted through the top opening of the casing section 11 exposing all three pistons for inspection or removal upwardly from their chambers. As suggested by FIG. 1, the various portions of compensation fluid passage or duct 0 are so formed in the casing section 11 and so related to the pistons 40a, P and P and their working chambers that, when the governor is installed in its usual upright position, any air or gas trapped in the compensation fluid will find its Way to the leak-off orifice controlled by needle valve R. In the normal or equilibrium positions of the compensation piston elements P and P those elements are so related to their respective working cylinders as not to form pockets that could tend to entrain or trap air or gas bubbles.

Referring to FIG. 4, ports 44 in the tubular hub or quill 18 or gears 17 and 20 are connected with duct 0 and intersect relatively enlarged or counterbore portion 45 in the lower end of the quill wall below the normal or equilibrium position of proportioner piston P, so that movement of that piston cannot close the ports. The lower end ofproportioner piston P may be formed with an extension 46 adapted to limit downward movement of the piston P as by contact with a plug 47 closing the lower end of counterbore 45. The proportioner piston P, as shown, is maintained in its free floating position for relative rotation of the piston and its coacting bore by a single non-rotatable coil spring 48 serving as a compression and tension spring as required at different times and having lower end coils 43 suitably attached to a stub portion of the piston P and upper coils 48" similarly attached to a stub 49 carried on the lower end of a bracket 50. The bracket can, as shown in FIG. 4, be secured as by screws to a side wall of the case section 11 above the proportioner piston and spring assembly. When the bracket 50 is detached from the case the entire assembly just mentioned can be readily removed for inspection or, if desired, for replacement of the piston-supporting spring 48 with one of'a different rate.

Assuming the governor oil is supplied from an engine driven pump whose output is connected to the interior of the governor case A, the general interior or sump portion of the case will be fully charged with governor oil at commencement of engine operation. The oil in the sump is replenished through the port S during operation of the power pistons. To limit the sump pressure at a low level (e.g. 1 or 2 p.s.i. above atmospheric pressure) the'base 10 as shown in FIG. 1 is provided with a one way acting valve 52 and loading spring 53, the valve discharging excess pressure oil in a direction toward the engine crankcase when the governor is operating to control a speed of an engine. A' pressure regulator mechanism of known or suitable type can be used instead.

Referring to FIG. 3, upper left, when iso-chronous governoroperation only will be required, and the speed droop mechanism 40 is therefore omitted, the bracket 55 for the fulcrum of the speed setting lever 33 is directly attached to the casing 11 as by one or more screws in the position indicated by broken lines at 56. When the permanent speed droop mechanism 40 is installed the bracket 55 is preferably supportedfor vertical movement as on a rod 58 secured to the casing by a bracket or guide member 59 fastened to the lower end of the rod 58. A coil spring 60 around the rod then acts upwardly against the bracket or guide 55 tending to raise the speeder lever 33. In that case the terminal shaft K operates through mechanism to be describedcontinuously to oppose the upward force of the spring 60 tending to raise the speeder lever 33.

As shown particularly in FIGS. 3 and 5, upwardly extending arm portions 55' of the bracket 55 support a horizontal pivot or fulcrum pin 62 for a speed droop lever 64 which, at one end, extends over the terminal shaft K and carries a roller 65 for contact with a suitably contoured cam 66 on the terminal shaft. A speed droop adjustment bracket 67 slidably supported on the underside of the cover 12 carries a shiftable pivot or fulcrum for the speed droop lever 64 in the form of a pin or bolt 68 adapted to slide along a slot 70 in the lever 64 from a position such as illustrated in FIG. 3 to various positions along the slot including a position (not shown) wherein the axis of the pivot pin 68 coincides with that of the fulcrum pin 62. With the pin 68 in the illustrated position, increase-fuel or counterclockwise movement of the terminal shaft K allows the spring 60 to raise bracket 55 and reduce the effective force of the speeder spring C; and the opposite, fuel decreasing, movement of the terminal shaft has the reverse effect as common in speed droop linkages. When the pins 62 and 68 are positioned in mutual alignment the governor is conditioned for isochronous or zero speed droop operation.

For adjusting the position of speed droop mechanism pivot pin 68, the speed droop bracket 67 is connected to a plate 71 on the cover 12 as by a clamping bolt and nut assembly 71', 72 movable along a slot 73 in the cover parallel to the longitudinal extent of the lever 64. Suitable graduations, not shown, are provided on the slide plate 71, as in region 75 thereof, FIG. 5, for association with an index mark (not shown) on the cover. The support for the fulcrum pin 62 in the arms 55 of bracket 55 preferably comprises open slots in respective bracket arms. Thereby the speed droop mechanism with exception of portions permanently carried by the bracket 55 can be lifted off with the cover 12; and upward movement of the cover also lifts the speed adjusting screw 36 out of operative association with the speed adjusting lever 33. An O-ring seal 77 occupying (e.g.) a circular groove in the top of the cover 12 cooperates with the lower face of the slide plate 70 to block leakage of governor oil through the slot 73.

As shown in FIG. the position of a stem portion of the needle valve R is shown in relation to. a plug 78 of the cover 12. This arrangement, with the plug removed, enables access to the needle valve for adjustment of compensation fluid leak-off rate. When the governor is expected to be used in positions other than vertical, the alternative needle valve mounting in the cover according to FIG. 6 is preferred. Needle valve stem R in FIG. 6 has a cylindrical enlarged diameter portion 80 extending through an O-ring seal 81 in cover 12; and, above the portion 80, the stem is reduced at 82 and adapted for engagement by an adjusting tool. When the cover 12' is removed for inspection or service to the governor, the enlargement at 80 relative to the portion 82 protects the seal 81 from being damaged in case operation of the adjusting tool has roughened the portion 82.

We claim:

1. A normally isochronous hydraulic speed governor unit including a centrifugal speed-error-detecting device, a hydraulic servo or power piston mechanism, and a pilot valve plunger operated by the speed-error-detecting device to control fluid for-operation of said mechanism, a main casing for said unit having a removable cover, the speed-error-detecting device including a coiled speeder spring operatingly connected to the pilot valve plunger and whose axis intersects the cover, and a speeder lever connected between its ends to the speeder spring and operated about a normally fixed fulcrum at one of said ends to set speed, characterized in that the fulcrum is spring biased for movement toward the cover on a guide member carried by the main casing member, a speed droop lever disposed generally parallel to the speeder lever has a fixed pivotal connection with the guide memberat one end of the speed droop lever and is operated upon at its opposite end as a function of power piston movement to swing the speed droop lever, a speed droop adjustment bracket is slidably mounted on the cover and is connected to support the speed droop lever on the cover through the intermediary of 'a' pivot pin carried by the bracket and movable along a longitudinal slot in the speed droop lever thereby to establish a variably positionable second pivot or fulcrum for the speed droop lever intermediately of its ends capable of being moved along the slot into coincidence with said pivotal connection between the guide member and speed droop lever for zero speed droop, and the pivotal connection between the speed droop lever and said guide member can be established and disestablished solely by movement of the cover onto and off the main casing member.

2. The governor mechanism according to claim 1 including a speed setting screw carried by the cover and having an operating connection with the speeder lever which can also be established and disestablished by said movement of the cover.

3. A hydraulic isochronous governor having a pilot valve including a valve plunger, speed responsive means connected to operate the valve plunger axially, and a servo motor hydraulically connected for control by axial movements of the valve plunger, a hydraulic compensation system comprising means defining a generally closed compensation fluid passage having a generally horizontally disposed portion with a leakofi orifice in a top wall thereof connecting the passage with a fluid storage space at low pressure, a piston rigid with the pilot valve plunger exposed to pressure in the passage, a compensation fluid pump connected for operation by the servo motor to pro duce pressure changes in the passage, an upright tubular member having a single axial bore with a smaller diameter portion defining a proportioner piston cylinder entirely above the passage, the bore having a larger diameter or counterbore portion therebelow with a lateral port intersecting its top end and communicating with the passage, a proportioner piston having a cylindrical lower end portion slidably sealing said smaller diameter portion, and two-way acting spring means connected yieldably to support the piston during steady state operation of the governor in a position such that the lower cylindrical end portion of the piston lies below the topmost wall surface of the port.

4. A- normally isochronous hydraulic speed governor unit including a casing, a centrifugal speed-error-detecting device, a hydraulic servo mechanism, a pilot valve, including a valve plunger connected for operation by said device to control fluid for operation of said mechanism, a drive shaft for the governor connected to drive said device through at least two gears, one coaxial with said device and the other having it axis offset from the rotational axis thereof, said other gear having an elongated tubular hub with an axial bore providing a piston chamber open at one end and generally closed at the opposite end, a compensation fluid passage in the casing including a leakofi-orifice, a pump connected for operation by the servo mechanism to produce pressure changes in the passage, pressure sensitive means on said valve plunger exposed to pressure in the passage, a port in the wall of the tubular hub connecting the generally closed end of said bore to the compensation fluid passage, a proportioner piston slidable in said bore and exposed at one end thereof to the fluid pressure of said passage, a helical coil spring extendthe casing and connected to the other end of the spring in such manner that the piston is non-rotatably and yieldably held axially in a predetermined normal position in said bore during steady state operation of the governor unit, the generally closed end of said bore including a counterbore portion intersected by said port and extending beyond the port away from said normal position of the proportioner piston so that the proportioner piston cannot close the port by moving past it.

2,333,184 Kalin Nov. 2, 1943 8 Kalin Feb. 8, Reg git) DEC; 12, Kalin Apr. 5, Burritt July 17, Parker Aug; 21, Moulton Dec. 23, Moulton Sept. 1, Feilden Apr. 13,

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