US2252838A - Governor - Google Patents

Description

1941- G. F. DRAKE EI'AL GOVERNOR Filed March 1' 1939 4 Sheets-Sheet l R RN N v E NTO as e Sowensen I (12.4% fw XZAJ-L-J QTTO JEyS Geo/"ye G aves/ Drake Gem-"9 Aug. 19, 1941.

' G. F. DRAKE ETAL GOVERNOR Filed March 17, 1959 4 Shepts-Sheet a NVENTQQIS 6601198 gorx'esfpra/fe Gear 2 Serena-en a 9341., C 44,. #11 W (ATTomeys G. F. DRAKE ETAL GOVERNOR Filed March 17, 1959 4 Sheets-Sheet 4 THROTTLE 20o osmomw H H H H H 1200RPM ENGINE SPEED Geo/ye GOrrQsf Drake Geo/"9e Sorensen f I cwcum, fx mflw (fi'rrolwsys f manta a 19, m1

assists GOVERNOR George I'erreet Drake and George Sorensen, bekfflm slslgnorstowoodward Governo Rockford, 111., a corporation or mm. Illinois Application m 11, use. sum No. scam a cum. (cam-s) This invention relates to a governor for regulating the speed of a prime mover or mechanism driven thereby and has more particular reference to governors in which the speed regulator is operated by a servo motor actuated by pressure fluid.

The general object of the invention is to provide a governor of the above character which is simple and inexpensive in construction, which is extremely sensitive to speed changes, which will maintain a selected speed within very close limits,

and which may be adapted readily to a wide. variety of diiierent locations and types of mountings.

Another object is to improve the speed regulation of such a governor by providing for automatically varying the amount of speed droop which is'eflective under different load conditions.

A further object is to provide a novel means for facilitating adaptation of the governor for operation of its driving member in either direction.

The invention also resides in certain novel structural characteristics which facilitate carrying out the foregoing objects and contribute to the simplicity of the governor construction and reliability of operation.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which range of throttle movement.

Fig. 9 is a characteristic speed droop curve of the governor.

While the invention is susceptible of various modifications and alternative constructions, we have shown in the drawings and will herein describe in detail the preferred embodiment. It

it is to be understood, however,.that we do not intend to limit the invention by such disclosure but aim to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

The governor shown for purposes of illustration is especially adapted for regulating the speed oi' aninte'rnal combustion engine and for this purpose is usually supported at one side of the engine on an adapter it through which is extended a mechanical connection including a shaft H for driving the governor in synchronism with the engine being governed. In the present instance, the speed ofthe engine is regulated by endwise shifting of a rod I! leading to the engine throttle and actuated by the governor. Preferably, the latter is supplied with actuating fluid delivered through a conduit II from an external source of supply such as the lubricating system of the engine.

The main operating parts of the governor are housed in a casing Hi the lower end of which is bolted to the adapter HIV and spaced therefrom.

by a plate It. The casing is open at its enlarged upper end It and carries a tubular extension or cap I! closed by a cover l8.

Speed changes of the engine are detected in the usual way by upstanding inertia weights or fiyballs 2| pivoted on horizontal pins 22 on a head 23 which rests on a ledge 24 and-is integral with the upper end of a sleeve 25 Journaled in a vertical bore" in the lower portion of the casing H. The lower end of the sleeve has a spline connection 21 with a coupling 28 pinned to the upper end of the drive shaft II. A collar 30 is forced onto the lower end of the sleeve to hold the latter against withdrawal. Integral. with the flyballs II are horizontal arms 28 which bear upwardly against the lower race ring 'II of a thrust bearing having antifriction elements or balls 82 disposed between the ring II and an upper ring 33. l The latterabuts against a flangeor shoulder 34 on a rod 35 reciprocable in the bore 38 of the sleeve 25 and carries an enlarged heador piston I! at its lower end cooperating with ports 38 in the sleeve 25 to form a control valve. Preferably,-the diameter 01' the ports is a few thousandths of an inch less than the length of the piston 31.

The valve functions to control the flow of pressure fluid or oil through a groove 38 around the sleeve and a passage 4| to and from the lower end of a vertical cylinder 40 bored in the casing M. A piston 42 reciprocates in the cylinder and cooperates therewith to form the servo motor tor actuating the throttle control rod l2. When the valve member ii is positioned as shown in Fig. 2,

the ports It are covered and the fluid held in the cylinder. Raising the valve member above or lowering it below this position connects the lower and upper parts of the sleeve bore 381 to the passage 4i through the ports 88 and the groove 88, thereby respectively permitting fluid to drain from and admitting fluid under pressure to the cylinder to. Fluid escaping through the lower end of the sleeve flows through openings 50 in the coupling 28 and drains through the adapter it back to the engine crank case or sump. Leakage through the valve parts into the upper part of the casing is is similarly returned to the sump through a passage til.

To simplify the motion transmitting connection, the flat upper end of the piston t? has a rolling and bearing contact with a rounded surface M on the free end of a crank at fast on the inner end of a rockshaft 45 (see Fig. i) which is journaled in a bushing 46. The bushing projects through and threads into a side wall of the casing. On its outer end, the rockshaft carries an arm t1 pivotally connected by a pin ti to one end of the throttle rod i2 and carrying a. head which abuts against one end of a spring at coiled about the rod. The other end of the spring bears against a stop $9 on the casing and acts in compression so as to urge the throttle rod to the left as viewed in Fig. 2, thereby tending to reduce the speed of the prime mover. throttle opening may be limited by an adjustable stop screw i threading into a lug 52 in the cap is and positioned to limit the upward movement of the arm 48. In the off position of the throttle, the piston rests against the lower end of the cylinder 48. 4 i I While for some applications the pressure developed in the lubricating system of the engine is sufficient to enable the throttle to be actuated with the required rapidity, it is preferred to employ fluid at higher pressure supplied by a booster pump incorporated in the governor. The pump shown is of the gear type comprising gears 53 and 54disposed in a recess 55 formed in the plate i5 and closed by the bottom of the casing it. The gear 53 rotates on a stud 58 while the gear 54 is splined on the lower end of the sleeve 25.

The extent of Opposite sides of the pump chamber 55 communicate with vertical passages 51 and 58 (Fig. 3) which constitute the pump inlet and outlet depending on the direction of rotation of the "with the interior of the sleeve above the valve piston 87.

I The end of the bore 59 which communicateswith the passage that is to be the-pump outlet as determined by the direction of rotation of the drive shaft ii is closed by a plug 65 which is threaded to render it removable. A sleeve 88 screwed into the other similarly threaded end of the bore 59 is connected externally of the easing to the fluid supply line I3. The inner end of this sleeve is received snugly in the bore 59 'beyond the passage 58 and has ports 81 and 58 spaced along its length. Through a'passage 88, the port 68 establishes constant communication between the fluid supply line i3 and the passage 58 which in this instance constitutes the pump inlet.

Slidable within the sleeve 56 is a valve member ii urged toward a cross pin H by a compression spring 13 disposed within the sleeve. With the member ii positioned as shown in Fig. 3, the port at is closed. In response to a pressure build up in the pump outlet and the supply passage leading to the control valve 31, the member ii will move to the left, uncovering a portion of the port it proportional to the pressure increase, thereby permitting fluid to be by-passed from the pump outlet to the pump inlet around the valve sleeve through the passage 59 which therefore serves as aeby-passage as well as part of the pump outlet and the fluid intake. In this way, the valve member ii operates automatically to maintain a pressure of the fluid supplied to the pilot valve predetermined by the stress of the spring 73.

It will be observed that the by-pass valve is self-contained within the threaded sleeve 88 and that the latter is mountable interchangeably in eitherend of the bore 59 so as to thereby adapt the governor for proper operation regardless of the direction of rotation of the drive shaft ii which will vary with different installations. By removing the plug and replacing it by the sleeve 58, fluid will be directed properly to and from the pump and to the pilot valve and will baby-passed properly when the shaft ii is driven in a direction to cause the pump to withdraw fluid from the passageBi and deliver the same to the passage 58. The governor may thus be adapted for reverse rotation of the shaft ii simply by reversing the positions of the plug and the sleeve 56 in the bore 59. In such a case, the fluid flow would be to the pump end of the speeder spring is seated on a washer '85 received on the upper end of the rod 35 above the flange 3t. With this arrangement, assembly of the parts is facilitated since the force of the speeder spring acting through the medium of the flange 84 effectually holds the parts together at all times. The upper end of the speeder spring receives and bears against a shoulder 15 on the cross head Ti. The latter is of inverted U-shape (see Figs. 3 and 4) with its legs 18' slidable in internal ways 19 formed in opposite walls of the casing I4 and extending parallel to the axis, of

the pilot valve and flyball head.

Adjustment of the stress under which the speeder spring is maintained may be controlled from a point outside of the governor casing as by shifting a hand lever 8 I held in different positions by a detent Bi coacting with a quadrant 8i The lever is connected to an external control rod 8i pivotally connected to an arm 83 on a rockshaft 84 which is journaled in a sleeve 85 screw threaded into the upper end portion of the casing I4. rockshaft is a crank 86 pivotally connected at 81 to one end of a lever 88 which overlies the cross head 11 and has a curved surface 89 intermediate its ends bearing downwardly against the upper Fast on the inner end of the surface of the cross head. The opposite end of the lever 88 is slotted as indicated at 8I to upper end of a rod 84 which is loosely received at its lower end in the upper end of the valve rod and held therein by a cross pin 88. A lost motionconnection is thus provided between the lever 88 and the valve rodso that by raising the pivot 81 above the normal range through which it is shifted to adjust the speeder spring, the lever 88 encounters the stop 88, thereby enabling the valve rod to be lifted positively to the shut down position.

When the prime mover being controlled is operating at the speeds determined by the setting of the speeder spring, the valve parts will be positioned as' shown in Fig. 2, the valve piston 8'! completely covering the ports 88 so that there is no flow of fluid either to or from the servo cylinder. All of the fluid delivered by the pump will then be by-passed through the sleeve 88 and the part "II back to the pump inlet. In response to a decrease in speed, the flyballs will move inwardly lowering the pilot valve member 85 and uncovering the ports 88 to pass fluid to the servo cylinder. The resulting pressure increase lifts the piston 42 and results in shifting the throttle rod I2 in the opening direction until the speed decrease has been corrected. When the engine speed increases, the flyballs move outwardly lifting the valve rod and connecting the passage H to the lower end of the sleeve bore 83. The

resulting flow of fluid from the cylinder 40 underf the action of the spring 48 permits the piston ation. This is effected in the present instance by swinging the lever 88 about the pivot 81 as a fulcrum in response to movement ofthe crank arm 44 by the servo motor. In the form shown in Figs. 2, 3, and 4, the fulcrum pin 82 is mounted on the depending arm of a bellcrank. 88 pivoted at 81 on a lug upstanding from the crank arm 44. Pivoted on the bellcrank 88 at a point 80 spaced from the pivot 81 is a link I'0I which hangs downwardly and ispivotally connected to an eccentric pin I82 on a shaft I 88. The latter is joumaled in a sleeve I84 threaded into the casing I4 to locate the axis of theshaft I88 coincident with the axis of the rockshaft 48. On its outer end, the shaft I08 carries a manually the position of the pin I82. Each selected setting of'the knob is maintained frictionally by the action of a spring I88 which urges the knob against the outer flanged end of the sleeve I04.

It will be apparent that for any fixed position of the pin I82, the bellcrank 88 will transmit the motion of the crank arm 44 to the slotted end of the lever 88. Since the pin I02 is oflset slightly from the center of the crank arm 44, a slight movement of, the pin 92 radially of the arm 44 may occur during movement of the arm, but this governor to different installations.

IiU

'- operable knob I08 which may be turned to vary change in theposition of the pin 82 is too small to be of material consequence. Through the action of the link IN and the adjusting pin I02, the motion transmitting ratio of the linkage is' varied over a considerable range in the adjustment of the pin I02 from its upper toits lower dead center positions. During such adjustment, the pin 82 is moved along the slot 8|. As a re-v sult of this adjustment of the motion transmitting ratio,'the amount of speed droop produced by the linkage will be varied correspondingly.

By interposing the link IOI between the eccentric pin I02 and the lever 88, provision is made for mounting the speed droop adjusting shaft I03 I and the throttle actuating shaft on a common axis. The sleeves 46 and I04 thus may be adapted for mounting interchangeably in the threaded bores on either side of the casing, thereby enabling the positions of the throttle rod and droop adjuster to be reversed relative to the governor casing as may be required in order to adapt the In making such reversal, the only part required to be changed is the crank 44.

For a similar reason, a threaded bore I01 (Fig. 4) of the same size as the bore in which the sleeve 85 is screwed is formed in the side of the casing I4 opposite the sleeve and in axial alinement therewith. This bore I0I'is closed by a plug I08 which may be removed and replaced by the sleeve 85 when the engine environment requires that the speeder spring adjustment be placed on the opposite side of the governor.

To explain the action of the speed droop mechanism, let it be assumed that the lever 8I and the knob I05 are positioned to establish the desired engine speed and droop. As a result, the fulcrum pins 81 and I02 are stationary, the lever thus being. adapted to swing about the then fixed pin 81 in unison with the arm 44 to which the lever is connected as above described by the bellcrank 80. In response to an increase in the speed of the engine, the valve rod 35 will be raised against the action of the speeder spring partially uncovering the ports 38 and permitting fluid to flow from the cylinder 4I and the piston to be lowered by the throttle spring 48. In this movement, the pivot 81 is lowered with the crank arm 44 and, through the medium of the bellcrank 88,correspondingly lowers the free endof the lever 88. As a result of this, the cross head 11 is lowered and the stress of the speeder spring increased and the governor thus conditioned for maintaining a slightly higher speed. The droop thus produced in the speed setting is approximately proportional to the movement of the I servopiston 42 and therefore the speed change causing the change in throttle setting.

In a similarway,"the setting of the speeder invention provides for a greater amount of effective speed droop under light loads than under heavy loads thereby compensating for the inherently greater acceleration possessed by the prime mover when operating under lighter loads. This may be accomplished through the provision of means which operates with changes in the position of the servo'piston and therefore the load condition to produce a greater deflection of the speeder spring for a given change in the position of the throttle rod I2 under light loads than under full loads. This modifying action may be produced either in the motion transmitting mechanism leading to the throttle or in the speed droop linkage itself. The former method is preferably employed.

In the present instance, the speed droop linkage is constructed so that its leverage remains substantially constant for a given speed droop setting and modification of the speed droop curve is producedin the throttle actuating mechanism. To this end, the crank arm 41 is mounted on itS rockshaft 45 to swing through an are a during movement of the throttle rod between idle and full load positions indicated in Fig. 8 which arc is disposed between the horizontal and vertical positions of the crank arm. Usually, the crank arm is arranged to overtravel in opposite directions beyond this are so as to provide for engine shut-down and a reserve fuel supply for abnormal loads, the crank moving through an arc 1) determined by the limiting movements of the servo piston 42.

Owing to the location of the arc a, the throttle movement produced by a'given movement of the servo piston 42 will equal the projection of the corresponding travel of the crank pin 41" on the line of reciprocation of the throttle rod. Thus, a somewhat greater movement of the servo piston will be required to produce a given travel of the throttle rod whenthe crank 41 is near the no load position than when the engine is operating near full load. Since the adjustment of the speeder spring 14 to produce speed droop .results from movement of the throttle rod, the

change in leverage thus obtained is reflected in a change in the effective speed droop under difrent loadconditions. That is to say. for a given movement of the throttle rod, there will be a actuating mechanism in which the throttle rod I2 is extended through the upper casing section II and slidable endwise therein. The rod is urged toward oi! position by a compression spring III acting ona collar II2 fixed to the rod. A compression spring II3, stronger than the spring III,

'acts between the collar and a block 4 rigid with one end of a sleeve 1 I5 encircling therod I2 between the block and a nut II6 by which'the position of the block along the rod may be adjusted to change the maximum throttle opening produced by the governor. The block constitutes the follower for a bifurcated cam II! in the form of an arm cast integral with and upstanding from The crank 44 previously referred to. The cam,

I plug III threading into the casing I4.

The foregoing arrangement permits of over-' riding the governor manually either to increase or decrease the fuel supply. By pressing on a knob IIQ, the spring I II may be overcome and the throttle opened independently of the governor. ,When the knob is pulled with a force sufficient to compress the spring II3 against the action of an hydraulic servo motor, the throttle will be moved to the left to decrease the fuel supply.

In this form. the speeder spring adjusting rocksleeve I20 which in turn is adapted to rock in a. bushing I 2| threaded into the casing I4. Fast greater movement of the cross-head l1 and a the engine under light load than when the throttle is near its maximum load position. This will be apparent from Fig. 9 which shows a characteristic speed droop curve e of the present governor shown in Fig. 9, when used in connection with one form of Diesel engine with a five per cent speed droop setting. It will be observed that the engine speed is a non-linear function of the load. Thus, at light loads, the slope of the curve and therefore the effective speed droop is greater as indicated by the tangent line 0 than at heavy loads as indicated by the line (1. In the illustration .given, the effective droop at the idle speed setting is approximately sixty per cent greater thanv at the full load setting.

By regulating the effective speeddroop in this manner, the increased tendency toward hunting during operation of the engine under light loads when its acceleration is greatest is overcome effectually. Greater stability in the operation of the engine and closer regulation of its speed are thereby obtained. As a result, it is possible with on the inner end of the sleeve is a crank I22 connected to one end of a rod I23 the other endof which carries a pin I24 projecting through and slidable along the slot 9| in the spring adjusting lever 84, The pin carries a roller I25 riding in a straight groove I26 in the operating crank 44. The outer end of the sleeve I20 has fast thereon a segment I21 which may be adjusted angularly to shift the fulcrum pin I24 back and forth along the slot 8|. droop adjustment thus produced is maintained by a set screw I28 threaded into the casing through a slot in the segment I21.

By virtue of its connection through the medium of the roller I25 and 'pin I24 with the main actuating lever 44, the lever 88 swings about the pivot 81 with changes in the position of the servo piston producing speed droop in-the manner-previouslydescribed. The effective mechanical advantage of the lever will be increased and decreased as the pin I24 is shifted outwardly and inwardly along the slot I26 thereby respectively increasing and decreasing the amount of inherent speed droop that will be produced.

' As in the governor first described, provision is madefor varying the movement imparted to the throttle I2 for a given increment of servo piston movement in' different parts of the operating range so as to produce a characteristic. speed droop curve of the character shown in Fig. 9. This may be accomplished simply and conveniently by shaping the cam surfaces III! as shownin Fig. '7. At or near the shut off position shown in full lines,- the cam produces a less throttle movement and therefore more effective speed droop for a given load or throttle change than is produced under full load as shown in dotted outline.

We claim as our invention:'

1. In a fiuid actuated governor, the combination of a hollow casing, a fluid control valve within said casing having an endwise shiftable The selected speed member, a head rotatable in said casing around the axis of said member and carrying fiyballs connected to the member, a. coiled speeder spring connected at one end to said member and acting to oppose said fiyballs, parallel slideways formed in opposite walls of said casing and extending parallel to said member, a cross head slidable in said ways and connected to the other end of said spring to form a guide therefor, and means for adjusting the position of said cross head to vary the stress of said spring.

2. In a governor, the combination of a valve having a rod shiftable axially in response to changes inthe speed of a rotary member, a

coiled compression spring urging said rod in one direction, a floating lever bearing intermediate its ends against said spring, a crank arm on one side of said rod connected at its free end to one end of said lever and adjustable to vary the stress of said spring, a second crank arm on the opposite side of said rod, a servo motor controlled by said valve and actuating said second crank arm, means pivotally connecting the other end of said lever and said second crank arm including a pin and slot connection, and means [or manually adjusting the position of the pivot pin along its slot.

3. In a governor, the combination of a valve having a rod shiftable axially in response to changes in the speed ofa rotary member, a coiled compression spring urging said rod in one direction, a floating lever bearing intermediate its ends against said spring and having fulcrums at either end, manually operable means for adjusting one of said fulcrums to vary the stress of said spring, a servo motor controlled by said valve, a motion transmitting connection between said element and said other fulcrum permitting of adjustment of the latter along the lever to vary the speed droop characteristic of the governor, and means for manually adjusting the position of said last mentioned fulcrum.

4. In a governor, the combination of a valve having a rod shiftable' axially in response to changes in the speed of a rotary member, a speeder spring urging said rod in one direction, a floating lever swingable about first and second fulcrums to adjust said spring, means for shifting one of said fulcrums to change the speed setting of said spring, a servo motor controlled by said valve and moving said other fulcrum to actuate said lever automatically and produce speed' droop, and means for manually adjusting said last mentioned fulcrum independently of said servo motor.

5. In a governor, the combination of a valve having a rod shiftable axially in response to changes in the speed of a rotary member, a

speeder spring urging said rod in one direction, a floating lever swingable about first and second iulcrums to adjust said spring, means for shifting one of said fulcrums to change the speed setting of said spring, and a servo motor controlled by said valve and moving said other fulcrum to actuate said lever automatically.

6. In a governor, the combination of a valve having a rod shiftable axially in response to changes in the speed of a rotary member, a speeder spring urging said rod in one direction, a lever for adjusting said spring, a servo motor controlled by said valve and having a movable element, a second lever for communicating the movements of said element to said first lever, said second lever having a shiftable fulcrum, and means for manually adjusting said last mentioned fulcrum independently of said servo motor. t

7. In a governor, the combination of a valve having a rod shiftable axially in response to changes in the speed of a rotary member, a coiled V compression spring urging said rod in one direction, a floating lever bearing intermediate its ends against said spring and having fulcrums at opposite ends, one being fixed and the other being shiftable longitudinally of the lever, a servo motor controlled by said valve and having a movable element connected to said shiftable fulcrum to produce speed droop, two concentric rockshafts, a crank on one of said shafts supporting said fixed fulcrum and adjustable to vary the speed setting of said spring, a crank on the other rockshaft connected to said shiftable fulcrum and adjustable to shift the latter along said lever.

8. In a governor, the combination of a speed responsive valve having a movable member, a speeder spring urging said member in one direction, two rockshafts arranged coaxially in end to end relation, a servo motor controlled by said valve and adapted to rock one of'said shafts back and forth, a lever system for transmitting the motion of said first shaft to said speeder spring, said system including a floating fulcrum, and means connecting said fulcrum and said other rock-shaft to permit of adjustment thereof by rocking of the shaft.

GEORGE FORREST DRAKE. GEORGE SORENSEN.

Images