US3225540A

US3225540A - Isochronous, centrifugally actuated, hydraulic governor

Info

Publication number: US3225540A
Application number: US401822A
Authority: US
Inventors: Darriel L Alsobrooks; Aram C Hamalian; Oldenburger Rufus
Original assignee: Curtiss Wright Corp
Current assignee: Curtiss Wright Corp
Priority date: 1964-10-06
Filing date: 1964-10-06
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28
Also published as: DE1576064A1; CH443924A; GB1109921A; NL6511955A

Description

Dec. 28, 1965 D. L. ALSOBROOKS ETAL 3,225,540

ISOCHRONOUS, CENTRIFUGALLY ACTUATED, HYDRAULIC GOVERNOR Filed Oct. 6, 1964 INCREHSE FUEL 55 q ATTORNEY United States Patent O M 3,225,540 ISOCHRONOUS, CENTRIFUGALLY ACTUATED, HYDRAULIC GOVERNOR Darriel L. Alsobroolrs, Birmingham, Mich., Aram C.

Hamaliau, North Caldwell, NJ., and Rufus Oldenburger, West Lafayette, 1nd., assignors to Curtiss- Wright Corporation, a corporation of Delaware Filed Oct. 6, 1964, Ser. No. 401,822 11 Claims. (Cl. 60--52) Our invention relates to improvements in hydraulic governors. One object is to provide an isochronous, centrifugally actuated, hydraulic governor for engines and other prime movers capable of being produced at lower cost than heretofore available operatingly similar governors. Another object is to provide a new and highly economical manner of producing adequate and approximately uniform supply pressure in a centrifugally actuated hydraulic governor.

In the present governor unit, as illustrated herewith, a rotor unit or assembly adapted to be driven at speeds proportional to the operating speeds of the engines to be governed has a ilyweight guided on the rotor for rectilinear movement transversely of its rotational axis and having a valve member operatingly integral with the yweight and arranged to control the rate of ow of operating fluid in a power amplifying servomotor mechanism having an output element connected to a control member (e.g., throttle or fuel metering valve) of the engine served by the governor. Prior governors of similar construction, at least as usually arranged, operate with permanent speed droop, and another object of our invention is to provide simple and effectual means for enabling stable isochronous, proportional plus rate responsive, operation in controlling prime movers. The prior hydraulic governors of the above outlined type are usually supplied with operating fluid from sources externally of the governors. In the present governor, indicating a further object, the rotor and its casing embody cooperating turbine pump elements of simple and inexpensive form functioning to maintain the necessary hydraulic pressures for operation of the servomotor mechanism. Such pump does not require relief valves or pressure regulators for maintaining suilciently uniform delivery pressure and can be made reversible (as to inlet and outlet) without requiring special or additional expense, as for auxiliary valve equipment.

The control valve, in the constructions as illustrated herewith, does not require a valve sleeve such as is usual in hydraulic governors. l

Other objects and novel features of our invention will become apparent from the following description of the illustrated embodiments as shown in the accompanying drawing, wherein:

FIG. 1 is a mainly diagrammatic or schematic cross sectional assembly view showing the present subject governor in one form;

FIG. 2 is a fragmentary sectional view taken along the indicating line 2-2 on FIG. 1 and showing intake and delivery portions of the turbine pump;

FIG. 3 is a sectional assembly view of the rotor taken along the indicating line 3 3 on FIG. 1;

FIG. 4 is a relatively enlarged fragmentary detail longitudinal sectional view of a speed adjusting rod assembly;

FIG. 5 is a fragmentary cross sectional assembly view similar to FIG. 1 showing a modified form of governor, and

FIG. 6 is a partial schematic view showing principally an alternate type of servo control valve arrangement.

In FIG. 1 the rotor unit 10 comprises principally a drive shaft member 11 and a head or block member 12, each of generally circular cross section secured rigidly together as by press tting or equivalent means or methods at com- 3,225,540 Patented Dec. 28, 1965 ICC plementary cylindrical surface portions in region 14. The shaft member has stepped diameter smoothly nished

cylindrical portions

15, 16 and 17 freely turnable in associated similarly smooth complementary bearing bore portions of

sections

19, 20 and 21 respectively of a stator or casing unit 18. The casing sections are removably secured together as by bolts or screws (not shown) at paired generally at

face surfaces

19', 20 and 20, 21', the construction embodying or including O-ring-type or other

suitable seal assemblies

24 and 25 and associated piloting labyrinth joints 26 as evident from the drawing.

Casing section 21 as shown embodies or contains the necessary output portion (servo M, cover not shown) of the governor servomotor mechanism and most of the necessary uid transfer passages for energizing and deenergizing the servo M as a function of operating movement or condition of parts of the pilot or control valve mechanism V of the servomotor mechanism contained in the rotor unit 10 as will be described.

The movable or plug portion of the valve mechanism V (FIG. 1) is a flyweight member 30 preferably formed of heavy metal such as tungsten and having land portions 31 and 32 (see FIG. 3 particularly) sealingly slidable in a transverse or diametrical guide bore 33 of the block member 12 of rotor 10 and normally covering valve ports 34 and 35 (FIG. 3) formed in the rotor block. For convenience the movable (i.e., plug and flyweight constituting member 30) of valve mechanism V will sometimes be referred to hereinafter as the pilot or control valve of the servomotor mechanism. Guide bore 33 is appropriately sealed at its two ends, as by plugs 37 and 38, at least one of which (38 as shown) is screw threaded or otherwise designed for removability.

The pilot valve and yweight member 30 is maintained in its illustrated normal or on speed position by centrifugal force acting on the principal mass portion of the member 30 and an opposed balancing and/ or biasing force of a helical speeder spring 40 around a stem portion 41 of the member 30 rigid therewith. The spring acts oppositely on a spring perch 42 carried by the stem 41 and a Speeder plug 43 slidably mounted in the bore 33. A spring-adjusting (hence speed setting) rod 45 has an oblique end surface portion 46 (FIG. 4) which forms an adjustable abutment in contact with a complementary cam surface 47 of the Speeder plug 43 to maintain selectable necessary spring force for holding the yweight member 30 against radial movement in the rotor 10 at desired engine operating speeds. Axial adjustment of rod 4S can be accomplished during engine operation through manipulation of an adjusting screw 48, suitably mounted in casing section 21, via a low friction or antifriction axial thrust bearing or swivel assembly 50 of suitable construction (see FIG. 4) between the rod 45 and screw 48. The screw 48, as shown, has a securing locknut 4S.

The thrust bearing 50, as shown in FIG. 4, comprises race members 51 and 52 which may be more or less loosely supported on the rod 45 and screw 48 respectively (to avoid binding in case of slight misalignment of rod and screw) and balls 53 in a ball-retainer ring 54 of conventional form.

Servo M, when designed for operation of rotary output or terminal shaft diagrammatically indicated 55 and connected in a manner not shown to a control member of the engine (e.g., throttle) preferably comprises

equal area pistons

56 and 57 differentially interlinked as through a lever 58 having unequal length arm portions so that pump output or supply pressure Ps in motor chamber 60 will in eect be exactly balanced by a lower pressure (control pressure Pc) in control chamber 61 when the engine is operating at set speed. Servo M and the control or pilot valve mechanism V thus function essentially as do 35 counterparts thereof in U.S. Patent 3,011,352 dated December 5, 1961 owned by the assignee of the present application. A more nearly conventional differential type servo, not shown, can of course be substituted for the illustrated servo M in case, for example, rectilinear output motion is desired.

The supply pressure Ps (to motor chamber 60) is furnished by operation of a duplex turbine type pump mechanism 64 of generally already known form per se. The pump 64, as more or less schematically shown, comprises two annularly continuous sets or series of pockets constituting turbine blades or

vanes

65 and 65 formed in the rotor 16 and closely associated

annular recesses

68 and 68 in associated casing sections and which are continuous about the axis L of the rotor except for a pressure dam portion 69, FIG. 2, separating pump inlet and outlet chambers or chamber regions 70 and 71 respectively, same view. The inlet chambers 70, one indicated in FIG. 2, are suitably connected (connections not shown) to negligible pressure or sump regions S within the casing 21, and the outlet chambers 71 are connected as at 71 to servo supply pressure chamber 60, FIG. 1. The illustrated duplicated sets of turbine blade assemblies 65, 65', etc. (each comprising a complete turbine pump) could, of course, be connected in series (booster arrangement, well known in the pump art) instead of being connected in parallel as shown. The illustrated bi-symmetrical arrangement of turbine elements is inherently hydraulically balanced axially of the rotor assembly.

Reversibility of turbine intake and delivery can be accomplished by formation (not specifically illustrated) of coating pairs of mating cavities or ports or passages in the annular casing section 21B and casing section 21, each pair functioning exclusively of the other pair according to selected, relatively reverse, positioning of the annular casing section 20 between the

casing sections

19 and 21. If for example outlet chamber 71 of annular section 20 has pump discharge cavity termini intersecting each `side face in the plane of line 1 1 on FIG. 2 (not so shown), thus requiring a single coacting passage in section 21 leading to servo chamber 6), the inlet chamber 70 would then have mating connections to sump at equal distances and radial locations on each side of said plane (e.g., as occupied by indications S and Ps in FIG. 2), the two sump connections respectively serving to supply the inlet chamber 70 according to the direction in which the shaft is required to be turned; and one of the sump connections in section 21 always being sealed by an lmperforate face portion of the casing section 20.

The control valve and flyweight member or pilot valve 30 is hydraulically balanced axially of itself via oppositely applied (PC) pressures in control valve chamber 75. Chamber 75 is connected as through an annular groove 76 (e.g., in the rotor) and a connecting passage 76 in the casing section 21 to the servo control chamber 61. Chamber '78 radially outwardly of the valve member 30 is similarly connected to a sump portion S as via an annular groove 79 etc. in the casing section 21. An annular groove Si) (e.g., in the casing section around the rotor 10 intersects the pump output chamber 71 and is intersected by a cross bore 34 (see FIG. 3) to enable connection of the pump output to the valve chamber 75 as controlled by land 31 for routing to the servo control chamber 61.

It will be evident from the above description in reference to the drawing, FIGS. 1 and 3, that overspeed error causes outward movement of the yweight and valve member 30 and admission of pump output or supply pressure fluid Via groove 80, port-constituting bore 34 and

passages

76, 76 to the control chamber 61 to cause decreased-fuel (counterclockwise) movement of the governor output or terminal shaft 55; and that underspeed error causes inward movement of the ywight and valve member 30, spilling uid from control chamber 61 via valve chamber 75 to sump S via valve port 35 and the annular groove 79 to which the port 35 is connected as by a suitable passage 35 in the rotor block 12.

In order to enable the mechanism as thus far described to operate stably and isochronously a hydraulic servoacutated feedback or compensation mechanism generally or operatingly similar to that of the above identified U.S. patent is provided. As shown diagrammatically in FIG. 1 the compensation system comprises an actuator piston piston 82 arranged for movement by the lservo M, as via a link 83, so as temporarily to change the fluid pressure in freely interconnected compensation fluid spaces identified Pn and, in effect, to modify the speed setting of the governor in a compensating direction whenever speed errors occur. The direction is one tending to oppose whatever movement of the valve member 30 takes place during occurrence of speed error, and the compensating force on the valve member 30 is then dissipated at a rate which may be adjusted as by a needle valve or leak-off valve assembly 85 of known or suitable form to mate the response characteristics of the governed engine.

The illustrated compensation system includes a two-wayspring-positioned proportioner piston 84, and the uid spaces adjacent the pistons 82 and -84 communicate freely with the diametrical bore 33 of the rotor 10 (block 12) between the valve and iiyweight member 30 and the plug 37 around the Speeder plug 43 through passageways extending along the speed adjusting rod 45. Rod `45 as shown by comparison of FIGS. 1 and 3 is of uniformly generally triangular form to provide appropriate passageways Within a cylindrical guide bore 45a for the rod formed in the associated reduced diameter portion 17 of the drive shaft portion of the rotor 10.

Since the temporary pressure increases and decreases in the compensation tluid spaces Pn are small as compared to supply pressures Ps and control pressures Pc the compensation fluid spaces are in effect isolated from the higher pressure spaces by permanent sump connections as by annular grooves 87 and 88 around the control valve member 30 and rotor portion 17, respectively communieating with sump regions S. Groove 87 in the valve member 31) continuously intersects sump-connected port 35 (FIG. 3) and groove 88 in rotor portion 17 communicates with the sump through a `suitable passage 88.

As noted above the valve and flywheel member 30 is of heavy metal. In case it is tungsten its unit mass is more than twice that of steel or other ferrous metal of which the rotor section 12 would preferably be formed. Tungsten has a much lower thermal expansion coeflicient than ferrous metal, hence the clearance around the lands of the valve member 30 becomes slightly greater with temperature rise and the valve mechanism then behaves somewhat like a so-called open-center or underlapped 3-way valve or a baied orice valve which is desirable in most cases (smoother action and less dead band).

In FIG. 5 the control valve etc. unit 30 of FIG. 1 is replaced by a valve unit having a single land portion 131 normally closing a valve port formed by a single bore 132 which is appropriately connected as via passage Pc with the servo control chamber, not shown. The space 130 shown as beneath the land portion 131 is connected to sump as will be apparent via passages 135, and the chamber or space 144 containing the Speeder plug 143 is subjected to pump outlet pressure Ps via interconnected passages 144. Compensation pressure space outwardly of the fiyweight and piston portion 131 of control valve unit 130 is connected to compensation fluid space Pn (shown at the upper right) through passages 151 as clearly shown, partly around the speed setting rod 145. The passages 151 containing compensation `Huid pressure Pn are isolated from the supply pressure chamber 144 by a sealing assembly 146 around the speed adjusting rod 145.

In operation the arrangement according to FIG. 5 differs from that of FIG. l partly in that radially outward or overspeed-error-detecting movement of the control or pilot valve liyweight portion 131 vents control pressure uid P,3 to sump (via chamber 136') and underspeederror-detecting movement connects pump pressure (Ps) output to the control chamber of the servo. Thus the design has to be such that action of the servo (not shown but corresponding to servo M) is essentially the reverse of that of servo M and the overspeed-error-responsive servo movement, via appropriate connections not shown, causes downward or Pn-pressure-increasing movement of actuator piston 132 rather than Pn-pressure-reducing or sucking movement as of piston 82 which .accompanies overspeed error. In FIG. 5 the supply pressure Ps in valve chamber 144 is isolated from the compensation fluid chamber 150 by a groove 187 around the flyweight and piston portion 131 of the control valve unit 130 and connected to the sump space or region 130 through the hollow stem 141.

It Will be apparent that since the single valve-portforming bore 132 in FIG. 5 replaces the two port forming bores 34 and 3S of FIG. 3 the single valve land construction of FIG. 5 can be produced with somewhat less expense than can the double land valve design.

In the control valve mechanism 230 according to FIG. 6 fiyweight member 241 biased by a spring 240 in a cross bore 233 has a bafiie or flap valve portion 242 for variably restricting or closing an oriiice 243 in normally ixed member 243 in the cross bore and communicating with a control pressure space or duct Pc leading to the servo control chamber 61 as indicated. The space Pc is supplied at low rate with pump output pressure uid PS through a fixed orifice 260; and at steady state the relative position of baie portion 242 and orifice 243 is such that enough fluid is bled from space lc to hold the servo piston 57 against movement. Overspeed error increases the rate of bleed and (through appropriate design of servo M, not shown but essentially the reverse of that according to FIG. l or as described in connection with FIG. 5) causes decreased fuel to the engine. Compensating fluid pressure Pn in chamber 250 is temporarily increased by feedback action during occurrence of overspeed error, or as described above in reference to FIG. 5.

In FIG. 6 the speed setting rod 245, which can be according to FIGS. 1 or 5., operates in conjunction with a spring 243 bearing radially outwardly on the member 243 while reacting on the rotor to adjust the relative position of the baiiie portion 242 and the valving orifice 243 occurring at a particular speed rather than by changing the loading as of the spring 240 which corresponds in operative effect to the speeder spring 40 of FIG. l. The end result (in either case) is to change the servo position at steady state, or in the absence of occurrence of speed error, as a function of movements ot' the rod 245 axially of the rotor.

We claim:

1. A hydraulic governor for engines comprising:

a casing having a generally circular recess,

a generally circular block generally filling the recess and adapted to be rotated therein at a speed proportionally to the speed of an engine to be governed,

a unitary speed error detecting valve and flyweight member contained in a diametrical bore in said block for speed error detecting movement out of a neutral position in said bore,

a hydraulic servo adapted for output movement to effect correction of such error,

means hydraulically connecting the valve member to the servo to initiate error correcting servo output movement as a function of speed error detecting movement of the valve member,

a source of hydraulic uid,

means including cooperating vanes on the circular block and an annular cavity on an adjacent Wall portion of the circular recess and constituting a turbine pump having an inlet chamber connected with said hydraulic iiuid source,

the turbine pump having an outlet chamber connected to' supply operating uid to the servo.

2. The governor according to claim 1 wherein both sides of the circular block axially thereof have respective sets of vanes cooperating with adjacent annular cavities, thus forming two turbine pumps.

3. The governor according to claim 2 wherein the two turbine pumps are duid-connected in parallel.

4. The governor according to claim 1 wherein an annular portion of the casing around the circular block is reversible in position between adjacent portions of the casing in a manner to reverse the input and output of the turbine pumps in respect to the servo when the direction of rotation of the block is reversed.

5. A hydraulic governor for an engine having a control member, the governor comprising:

a stationary casing having a generally circular cavity,

a rotor unit adapted for rotation at speeds proportional to engine speeds and having a generally circular portion generally filling the cavity,

a servo having supply-pressure-receiving and controlpressure-receiving chambers and pressure responsive displacement means adapted for connection to the engine control member and having surfaces respectively exposed to pressure in said chambers,

a source of hydraulic fluid,

turbine pump means including vanes on the circular portion of the rotor,.and further including an associated annular channel portion of said cavity having a pressure dam portion, the pump means having an inlet connected to said source and an outlet connected to the supply-.pressure-receiving chamber of the servo,

a speed-error-responsive control valve unit in the rotor unit,

said speed error responsive unit including a diametrical bore in the circular portion of the rotor unit,

a valve and flyweight member in the bore, and yieldable biasing means acting on said member to oppose centrifugal force, and further including port means in the rotor variably restricted by centrifugal positioning of the valve and iiyweight member,

"aid port means being connected with the control pressure chamber of the servo variably to etfect positioning of said displacement means thereof in accordance with detected speed errors.

6. A governor according to claim 5 wherein said yieldable biasing means is arranged to be adjusted mechanically to set speed while the governor is in operation.

7. A governor according to claim 5 wherein a screw, threaded to the casing along the axis of rotation of the rotor unit, is arranged, via low friction thrust bearing means, to move an adjusting rod along said axis, the rod having a camming connection with said yieldable biasing means to enable change of speed setting while the governor is in operation.

3. A control valve and yweight mechanism for a hydraulic speed governor having a hydraulic servo adapted for Iconnection with an engine to control its speed,

said mechanism comprising a drive shaft having a rotary head adapted for rot-ation at a speed proportional to engine speed,

said head having a diametrical bore,

a con-trol valve and flyweight unit in said bore including spring means normally maintaining the valve in a neutral condition,

the valve having a flow controlling port hydraulically connected to the servo to initiate speed controlling movements thereof, in response to occurrence of speed error,

a member movable radially in said bore and operatingly associated with the valve and fiyweight unit so as to enable selection of various operating speeds within a predetermined governing range, speed setting means including a rod coaxial with the -shaft and havingY a force transmitting abutment con-k nection with said radially movable member operative to change the radial position of the member as a function of axial adjustment of the rod,

and means capable of manual adjustment during operation of the engine and capable of changing the axial position of .the rod.

9. The mechanism according to claim 8 wherein said member movable in said bore has a valve orice which is variably restricted by the valve and yweight unit incident to occurrence of speed error.

10. A control valve and fiyweight mechanism for a hydraulic speed governor having ya hydraulic servo adapted for connection with an engine to `control its speed,

said mechanism comprising a drive shaft having a rotary head adapted for rotation at a speed proportional to engine speed,

said head having a diametrical bore,

a control valve and 'yweight unit in said bore,

the valve being hydraulically connected with the servo to initiate speed controlling movements thereof,

biasing spring means in the bore acting on the valve and Iflyweight unit to oppose centrifugal force thereon,

and speed setting means for adjusting the loading of the spring,

said speed setting means including a rod coaxial with the shaft,

`cooperating force transmitting means between the rod and spring such ythat axial movement of the rod causes change in effective force of the spring means on the yweight portion of said unit,

and a normally stationary screw having a Iswivel connection with the rod, the screw `being manipulatable during rotation of the shaft to set speed.

11. An isochronous hydraulic governor comprising:

a drive shaft having a head portion,

a casing having a circular cavity containing the head portion and wherein the head portion can be rotated by the shaft,

a hydraulic servo in the casing having an output portion for speed regulating connection with an engine,

a pilot valve member for controlling lthe servo located in a diametrical bore in the head portion and having a fiyweight portion and spring means cooperating to position the valve member according to detected speed error,

passage means between the valve member and servo and -controlled by speed-error-detecting movements of lthe valve member in said bore to control the servo output portion,

a hydraulic feedback circuit including a leakoff orifice and an actuator connected for operation Iby t-he servo to increase and decrease pressure in the circuit as functions of servo output movements,

and receiving displacement means located in said bore and connected for biasing action on -the pilot valve member during such servo output movements.

No references cited.

IULIUS E. WEST, Primary Examiner.

Claims

1. A HYDRAULIC GOVERNOR FOR ENGINES COMPRISING: A CASING HAVING A GENERALLY CIRCULAR RECESS, A GENERALLY CIRCULAR BLOCK GENERALLY FILLING THE RECESS AND ADAPTED TO BE ROTATED THEREIN AT A SPEED PROPORTIONALLY TO THE SPEED OF AN ENGINE TO BE GOVERNED, A UNITARY SPEED ERROR DETECTING VALVE AND FLYWEIGHT MEMBER CONTAINED IN A DIAMETRICAL BORE IN SAID BLOCK FOR SPEED ERROR DETECTING MOVEMENT OUT OF A NEUTRAL POSITION IN SAID BORE, A HYDRAULIC SERVO ADAPTED FOR OUTPUT MOVEMENT TO EFFECT CORRECTION OF SUCH ERROR, MEANS HYDRAULICALLY CONNECTING THE VALVE MEMBER TO THE SERVO TO INITIATE ERROR CORRECTING SERVO OUTPUT MOVEMENT AS A FUNCTION OF SPEED ERROR DETECTING MOVEMENT OF THE VALVE MEMBER, A SOURCE OF HYDRAULIC FLUID, MEANS INCLUDING COOPERATING VANES ON THE CIRCULAR BLOCK AND AN ANNULAR CAVITY ON AN ADJACENT WALL PORTION OF THE CIRCULAR RECESS AND CONSTITUTING A TURBINE PUMP HAVING AN INLET CHAMBER CONNECTED WITH SAID HYDRAULIC FLUID SOURCE, THE TURBINE PUMP HAVING AN OUTLET CHAMBER CONNECTED TO SUPPLY OPERATING FLUID TO THE SERVO.