US2702700A - Governor mechanism - Google Patents

Description

Feb. 22, 1955 Original Filed Nov. 14, 1946 B. O. BURRITT GOVERNOR MECHANISM 2 Shets-Sheet 1 I ,1; id 20 (/54 /4 I: /2 /jf I a I a .15 I K 2 Dam 4 E INVENTOR.

Feb. 22, 1955 B. o. BURRlTT GOVERNOR MECHANISM 2 Sheets-Sheet 2 Original Filed Nov. 14, 1946 INVENTOR. Bvrneil 0. Bin-riff.

HTTOR/VEYS United States Patent 3 GOVERNOR MECHANISM Burnell O. Burritt, Detroit, Mich.

4 Claims. (Cl. 2671) This invention relates to governor mechanism, and

more particularly, to mechanisms of the type known in the art as isochronous governor mechanisms for regulatmg the speed of prime movers and other controllable rotating mechanisms.

This application is a division of the copending application of hurnell O. Burritt on Governor Mechanism, Serial 709,768, filed November 14, 1946, now U. S. Letters Patent No. 2,594,866, granted April 29, 1952.

The principal objects of the invention are to provide an improved governor mechanism which is extremely simple in construction, economical of manufacture and assembly, and reliable and eflicient in operation; to provide such an improved governor mechanism of the hydraulic type, which is positive in action and of a rugged construction unafiected by dirt particles and air bubbles which render the usual forms of governors ineffective and inaccurate; to provide, in such a governor mechamsm, an improved compensating means effective to minimize the speed fluctuations of a governed mechanism during changes in the load imposed thereon and having such improved characteristics that the usual secondary compensating means is rendered unnecessary; to provide an improved governor mechanism permitting closer regulation with less speed deviation in the governed mechanism than has hitherto been possible; to provide, in such a governor mechanism, an improved speeder spring which is extremely simple in construction economical of manufacture and which provides a governor mechanism having greatly improved operating characteristics; to provide such an improved speeder spring which permits adjustment of the inherent stability of the governor; to provide an improved governor mechanism which may be readily adjusted for efficient and accurate regulation of various types of engines; and to generally improve the construction and operation of overnor mecha nisms of the above generally indicated type.

With the above as well as other and, in certain cases, more detailed objects in view, which will become apparent from a consideration of the following specification and appended claims, preferred but illustrative embodiments of the invention are illustrated in the accompanying drawings throughout the several views of which like reference characters designate like parts and in which:

Figure 1 is a view in transverse section of a governor mechanism embodying the present invention;

Figure 2 is a fragmentary view in section of a modified form of the invention;

Figure 3 is a fragmentary View in section of a further modification of the invention; and,

Figure 4 is a view in transverse section of the structure illustrated in Figure 3 taken substantially along the line 44 thereof.

ing a hydraulic pump connected with a fluid motor through a pilot valve which is responsive to the speed of rotation of a fiyball mechanism which is operatively connected to and responsive to speed changes of the prime mover to be governed. In an illustrative, but not ice in a limiting sense, except insofar as is defined in the claims, the invention is so disclosed herein.

Referring to Figure 1 of the drawings, the governor mechanism is enclosed in a housing and includes a gear pump generally designated 12, which employs a. pair or meshing gears 14 and 16. The gear 14 is drivingly connected to a shaft 18 extending outwardly of the housing 16 and driven by, and responsive to, speed changes of the prime mover to be governed. The other gear 16 of the pump 12 is operatlvely connected to a shaft 20 which is journaled in a radially inwardly projecting boss 22 integrally formed on the casting 10. At its upper end, the shaft 20 carries a gear 24 which drivingly engages the lower of a pair of integrally connected gears 26 and 28, the other of which drives an idler gear 3%, which in turn drives a gear 32 upon which is mounted a pair of fiyballs 34. The gear 32 is journaled on the upper end of a valve sleeve 35 which is supported in the housing projection 22 along a substantial portion of its length. The valve sleeve 35 has an axially extending opening 36 and three axially spaced annular grooves 38, 4 B and 42, formed in the portion thereof disposed within the projection 22. Each of the annular passages 38, 40, and 42 communicates with the central passage 36 through a plurality of radially extending ports 44, 46, and 48, respectively.

The intake side of the pump 12 opens into the lower portion of the housing 10 well below the level of fluid carried therein, and its discharge side is connected, through a conduit which is provided with a by-pass or relief valve 52, to the annular passage 38 and ports 44 in the valve sleeve 25.

The housing 10 also carries a fluid motor 54 having a cylindrical chamber 56 and a piston 58 adapted for reciprocation therein. The piston 58 carries a pair of oppositely extending shafts 60 and 62 secured thereto for reciprocation therewith. The shaft 60 extends outwardly of the motor 54 and is adapted for connection to fuel or other power medium control means associated WiLh the prime mover to be governed. The oppositely extending shaft 62 projects into the housing 10 for cooperation with the governor compensating means which will be hereinafter described. The chamber 56 connects with the annular passage 4% and ports 46 through a conduit 64 which is connected to the motor 54 on one side of the piston 58 and adjacent one end of the cylinder 56. A coil spring 66 is mounted in the chamber 56 on the opposite side of the piston and opposes the hydraulic pressure applied to the other side of the piston through the passage 64.

This hydraulic pressure applied to the motor is controlled by a valve rod 70 mounted in the axial opening 36 of the valve sleeve 35 and having a portion 72 of reduced diameter the length of which is substantially equal to the distance between the adjacent edges of the ports 44 and 48. With this construction, it will be apparent that when the valve rod 70 is in the position illustrated in Figure 1, the ports 46 which communicate with the passage 64 are closed from both the ports 44 and the ports 48, but that a slight movement of the valve rod 70 downwardly will establish communication between the ports 44 and the ports 46, thereby permitting pressure from the pump 12 to be applied to the motor through the line 50, the valve mechanism, and the line 64. Similarly, it will be apparent that a slight movement of the valve rod 70 in an upwardly direction from the position illustrated, will establish communication between the ports 46 and 48, thereby permitting the spring 66 to expand, forcing fluid from the motor through the line 64 and ports 46 and 48, and into the annular passage 42 from which it flows into the housing 10 through an aperture 74.

For controlling the axial position of the pilot valve 70, the fiyballs 34 are in the form of pivotally mounted bell cranks having inwardly extending arms 76 which engage a thrust washer 78 secured to the valve rod 70 for moving the valve rod in one direction. During operation of the governor, the centrifugal force urging the flyballs 34 outwardly, acts through the lever arms 76 and the thrust washer 78 to urge the pilot valve 70 upwardly. This of the flyballs 34 carried by the latter.

force is opposed by the downwardly acting force of .a speeder spring 80, one end of which is anchored to the housing and the other end of which engages the upper end of the valve rod 70 to urge it downwardly. When the load is constant and these forces are in balance, the governed mechanism operates at a steady speed.

From a consideration of the above described strucrure it will be apparent that a change in'the speed of the prime mover will produce a corresponding change in the speed of rotation of the flyballs 34, which are connected to the prime mover through the shaft 18, the gears 14 and 16, the shaft 20, and the gears 24, 2'6, 28, .30 and 32. It will also be apparent that such a change in 'speedwill disturb the balance between the force exerted on the valve rod 70 in one direction, by the fly- .balls .34 acting against the thrust washer 78, and the force exerted on the rod in the opposite direction by the speeder spring 80. For example, when the prime mover slows down, as when the load thereon is increased, .the flyballs 34 slow down correspondingly, reducing the centrifugal force acting thereon, and permitting the valve rod 70 to bepushed downwardly by the speeder spring .80. This downward movement of the valve rod 79, as :described above, establishes communication between the ports 44 and 46, thereby connecting the pump 12 to the line 64 and through it to the motor 54. This piston 58 is thereby moved upwardly, as viewed in Figure 1, cansing the shaft 69 to open the throttle of the prime mover or'otherwise increase its power medium. In the absence of any compensating means, this opening of the throttle would continue until the prime mover, and hence the fiyballs 34, were again operating at their initial speed. .As a result of this continued movement of the piston 58, the throttle of the prime mover would have been opened considerably beyond the setting required to run the prime mover, with its new load, at the initial speed. As a result, the speed of the prime mover and of the flyballs 34 would continue to increase, the flyballs 34 moving outwardly as a result of the increased speed, and raising the valve rod 70 against the action of the spring 80. In this raised position, the line 64 would be connected through the ports 46 and 48 to the discharge aperture ,74 permitting fluid to flow from the motor back into the housing 10 under the pressure of spring 66, the motor piston 58 moving downwardly and the shaft 60 closing the throttle. The same over-shooting would again occur and the throttle would be closed beyond the desired setting, and consequently the operation of the prime mover would be very erratic.

The above mentioned gears 24, 26, 28, 30 and 32, in addition to forming a part of the driving connection between the shaft 18 and the flyballs 34, comprise, by their proportions and arrangement and the manner in which they are mounted, a primary part of the compensating means by which the governor mechanism of the present invention eliminates the above described overshooting and erratic operation.

The idler gear 30 is rotatably mounted on a fixed spindle 82 which is' supported on the housing 10 coaxially with the gear 24, by any suitable means (not shown). The integrally formed gears 26 and 28 are rotatably mounted on an arm 84 which is pivotally supported at one end, on the spindle 82, and the outer end 86 of which is bifurcated to provide a driving engagement with the upwardly extending leg 88 of a pivotally mounted bell crank 89, the other leg 90 of which is held in engagement with the upper end of the shaft 62 by a spring 92 anchored on the housing 10 and secured to the leg .88 of the bell crank. The relative proportions of these gears 24, 26,.28and 30 are such that if the gear 24 is held stationary and the arm 84 is pivoted about its point of support on the spindle 82, there will be a consequent rotation of the gears 26, 28, 30 and 32 and, therefore,

It will also be apparent that the amount of rotation of the flyballs 34 during such movement of the arm 84 is entirely dependent upon the relative proportions of the gears 26, 28, 30 and 32'and the amount of movement of the arm 84.

Under these conditions, that is, when the gear 24 is held stationary, the direction of rotation of the flyballs is reversedby reversing the direction of movement of the.

arm 84. From the foregoing, it will be seen that when the gear 24 is driven by the prime mover, as innormal operation of the governor mechanism, any pivotal movein the opposite direction it will act to decrease the speed of rotation of the flyballs relative to that of the prime mover.

Considering again the operation of the governor mechanism when the load on the prime mover is increased,

and incorporating the operation of the above-described compensating means, the prime mover and the flyballs 34 will slow down disturbing the balance between the forces exerted on the valve rod by the flyballs and the speeder spring and permitting the speeder spring 80 to force the valve rod 70 downwardly with the consequent amplification of hydraulic pressure to the piston 58 .described above. This hydraulic pressure forces the .piston 55 upwardly, as viewed in Fig. 1, against the action of the spring 66 and, through the movement of the tie+rod 60, opens the throttle of the prime mover. Also during this upward movement of the piston 58,- the upwardly extending shaft 62 engages the leg of the pivotally mounted bell crank 89 and, through the connection :of its other leg 88 to the outer end of the arm 84, Pivots the latter rearwardly from the plane of the paper, as

viewed in Fig. l, and increases the speed of rotationof the flyballs 34. The amount of this artificially produced component of the speed of the flyballs 34 depends upon the proportions of the gears 24, 26, 28, 30 and 32 and the speed of movement of the arm 84, as above .described. When the sum of this component and the speed component of the flyballs produced by the. prime mover equals the initial speed of the flyballs, they resume their initial position and the valve rod closes the port 44, thereby stopping the application of pressure to themotor 54 and thus stopping the opening of the throttle of the prime mover before the prime mover has resumed its initial speed.

It will be appreciated by those skilled in the art that optimum regulation and eliminating of over-shooting and hunting can be accomplished only by balancing the individual governor mechanism to the particular prime mover upon which it is installed. The balancing is required because the difference between the throttle setting required to bring the prime mover up to speed and that required to maintain it at that speed, varies in diiferent engines, even of the same type. The balancing of a particular governor and prime mover is accomplished by adjusting the governor mechanism to vary the amount of the artificial speed component introduced into the speed of the flyballs by a given movement of the piston 58. This may be accomplished in any suitable manner, as, for example, by providing means for adjusting the pivotal mounting of the'bell crank 89 to vary the effective length of the lever arm 90 thereof against which the shaft 62. carried by the piston 58, acts. In this manner, the artificially induced component of the speed of the flyballs may be adjusted to accurately compensate for the difference between the throttle setting required to bring the prime mover up to speed and that required to maintain it there, with the result that the movement of the motor piston and hence the opening of the prime mover throttle, will be stopped when the throttle s'etting is' that required to exactly balance the new load condition and the prime mover will resume operation at its initial speed and carry the new load. 7

Similarly, when the prime mover speeds up because of a reduction in its load, the flyballs move outwardly, raising the valve rod 70 and permitting a downward movement of the piston 58 and the flow of fluid from the motor 54 into the housing 10. During this movement the spring 92, acting through the leg 88 of the bell crank,

pivots the arm 84 forwardly out of the paper, as viewed in Fig. l, producing an artificial decrease .in the speed of the flyballs and a correspondingly early return of the flyballs to their initial position and a resulting arresting of the throttle closing before the speed of the prime mover has dropped to its initial level, preventing overshooting or hunting.

Numerous attempts have been made in the pastito design a simple governor speeder spring which may be economically and accurately constructed, and which at the same time permits highly sensitive governing over a wide range of speeds. Considerable difiiculty has been encountered in building such springs because of the nature of the forces acting against them. As indicated above, the speeder spring acts against the valve rod to urge it in one direction and the centrifugal force of the flyballs act through the arms 76 to urge it in the opposite direction. This centrifugal force varies directly with the square of the speed of rotation of the flyballs and also varies directly with the radius of rotation of the flyballs. The latter, of course, is important only during the intervals in which the flyballs are not rotating at their initial speed. When they are rotating at this predetermined speed they are in the position illustrated in the drawings and the radius does not vary. To insure a condition of stability during such speed variations, it is necessary in any governor mechanism that the scale, or ratio of force to deflection, of the speeder spring be greater than that of the flyball mechanism.

The speeder spring illustrated in Figure 2 is of the conventional type which attempts to attain the desired uniform sensitivity over wide ranges of speeds by employing coils of varying diameters and pitches, which progressively become inoperative as the upper end of the speed range is approached. These springs, however, are extremely difficult and expensive to manufacture with the desired accuracy.

The present invention attains the desired highly sensi tive regulation throughout the speed range by the use of the speeder spring mechanism illustrated in Figure 1. This mechanism comprises a flat spring strip 80 which may be a stamping which may be easily and accurately duplicated in any desired quantity. The spring strip 80 may be and preferably is reversely turned, forming an eye 93 at one end to receive a pin 94 which serves to anchor the spring to the housing 10. The other end of the spring strip 80 engages the upper end of the valve rod 70 to urge the latter in a downward direction in opposition to the centrifugal force of the flyballs transmitted thereto as above described.

The pressure of the spring strip 80 against the valve rod 70, and hence the speed setting of the governor mechanism, is controlled by means of a roller 96 which engages the upper surface of the strip 80 and is mounted in one end of a link 98. The other end of the link 98 is pivotally connected to one end of a lever 100, the other end of which is pivotally supported on the housing by a bolt 102 or any other suitable means. The lever 100 is held in adjusted position between a pair of opposed set screws 104 supported in and having a threaded engagement with ears 106 integrally formed on or otherwise suitably carried by the housing 10. The purpose of this adjustment will be hereinafter described.

The link 98 is pivotable about its above-mentioned connection to the lever 100, and is held at the desired setting by means of a crank 108 pivotally mounted on the housing 10 and connected to and operable by suitable handle means disposed externally of the housing. The crank 108 is connected to the link 98 by a tie rod 110 one end of which is secured to the link 98 intermediate its ends and the other end of which is secured to the outer end of the crank 108. It will be apparent from the abovedeseribed structure that movement of the crank 108 in a counterclockwise direction, as viewed in Fig. 1, will cause the roller 96 to move downwardly and to the left in a circular arc about the pivotal connection of the link 98 and the lever 100. During this movement, the effective length of the spring strip 80 is decreased as the pressure on the spring strip is increased. This construction affords the necessary spring scale for stability during speed variations as described above. It is well known that each prime mover has difierent inherent stability characteristics, even as between prime movers of the same type. This necessitates adjusting the governor mechanism for each application, at the time of installation. This is accomplished by means of the set screws 104 which control the position of the lever 100 and therefore of the arc along which the roller 96 moves when the speed setting of the governor is changed. The lever 100 is thus adjusted, empirically, to the position in which optimum regulation is obtained over the desired speed range.

A modified form of the invention is illustrated in Fig- 1 me 2, in which the above described speeder spring mechanism is replaced by a conventional coil spring 120 of the above-mentioned type in which the diameter and pitch of the coils vary. The lower end of the spring seats on the upper surface of a washer 122, corresponding to the washer 78 of the previously described embodiment, and pressure is applied to the upper end thereof through a vertically disposed head 124 which engages the upper end of the spring. The head 124 is pivotally mounted in the outer end of a crank 126, the other end of which is pivotally supported on the housing and is connected to and operable by any suitable speed setting means disposed externally of the housing.

Figures 3 and 4 illustrate a modified form of driving mechanism which may be employed to replace the gears 24, 26 and 28, the arm 84, and the bell crank 89 of the embodiment illustrated in Figure l. The modified driving mechanism comprises a pair of coaxial shafts and 132, one of which corresponds to the shaft 20 and the other of which is adapted to carry a gear (not shown) corresponding to the gear 30. The adjacent ends of the shafts 130 and 132 carry spaced, parallel, and opposed, bevel gears 134 and 136, respectively, which are drivingly interconnected by a third bevel gear 138 rotatably supported on a shaft 140 disposed at right angles to the coaxial shafts 130 and 132.

A hollow T section 142 is disposed intermediate the gears 134 and 136 and journals the adjacent ends of the shafts 130 and 132. The inner end of the shaft 140 extends into the remaining branch of the hollow T section 142, and the shaft 140 is supported thereby as a cantilever. At its outer end the shaft 140 carries a ring gear 144 coaxial with said shafts 130 and 132 and having spur gear teeth formed on its outer periphery. From a consideration of the above structure it will be seen that the ring gear 144 corresponds to the lever 84 of the embodiment illustrated in Figure l, and that when the shaft 130 is held stationary, rotary movement of the ring gear 144 will likewise rotate the fiyballs, which are connected to the shaft 132, in the same manner as the above-described movement of the lever 84 in that embodiment.

In the embodiment illustrated in Figures 3 and 4, rotary movement is imparted to the ring gear 144 in response to the movement of the piston 145 of the fluid motor, by the engagement of the ring gear 144 and a rack 146 carried by a shaft 148, which corresponds to the shaft 62, and is likewise secured to the motor piston.

From the foregoing it will be appreciated, as in the embodiment illustrated in Figure 1, movement of the motor piston will introduce an artificial component into the speed of the flyballs and eliminate the undesirable overshooting or hunting, in the manner there described.

Although only three specific embodiments have been illustrated and described in detail, it will be apparent to those skilled in the art that numerous other modifications and changes may be made without departing from the spirit of the invention or from the scope of the appended claims.

What is claimed is:

1. In a governor mechanism for an internal combustion engine and having a control shaft movable axially to effect changes in the setting of the throttle of said engine, a speeder spring mechanism for controlling the position of said shaft and comprising a spring strip having a portion engaging said shaft to urge said shaft axially in one direction, supporting means engaging said strip in spaced relation to said portion, means engaging said spring strip intermediate said portion and the engagement of said strip by said supporting means for preloading said strip and adjustable for moving the point of engagement of said last named means with said strip along said strip for obtaining a predetermined effective length of said strip for a given adjustment of said last named means, the efiective length of said strip remaining substantially unchanged for a given adjustment of said last named means independently of movement of said shaft.

2. The combination defined in claim 1 wherein said last named means includes an element engaging said strip and movable along a path at least a portion of which has a slope such that movement of said element toward said portion of said strip produces an increase in the preloadiug of said strip for a given position of said shaft.

3. The combination defined in claim 1 wherein said last named means includes an element continuously engaging said strip, means mounting said element for move ment along a circular arc, and means for varying the disposition of said arc.

"4..'The combination defined in claim I1 wherein said 1,408,300 7 Houdaille Feb. 28, 1922 lastnamed'means includes a lever, means pivotally mount- 1,927,97 3 Bull Sept.'26, 1933 ingfsai'd lever, a link pivotally connected to said lever, 2,224,717 Austin Dec. 10, 1940 ancia roller rotatably mounted insaid link and engaging 5 FOREIGN PATENTS sai' strip. a V V 3,139 Great Britain 1914 References Cited in the file of thisv patent 116,337 Great Britain June 18, 1918 UNITED STATES PATENTS 1,324,198 Krebs et al. Dec. 9, 1919 10

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