US2594866A

US2594866A - Governor mechanism

Info

Publication number: US2594866A
Application number: US709768A
Authority: US
Inventors: Burnell O Burritt
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-14
Filing date: 1946-11-14
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 29, 1952 B. o. BURRITT GOVERNOR MECHANISM 2 SHEETS-SHEET 1 Filed Nov. 14, 1946 Jwerens-e Decrease INVENTOR. Bvrnezl Q Bvrrz Zt 1 I\ 1. 2 2 w M .1 l W a, M L L l 12 I .4 v fig??? 4 Q \d y V April 29, 1952 B. o. BURRITT GOVERNOR MECHANISM 2 SHEETSSHEET 2 Filed Nov. 14, 1946 f u W "J v/ E O/@ m P. J R W m 10 Z 8 n r v m B Patented Apr. 2 1952 UNITED STATES PATENT OFFICE GOVERNOR MECHANISM Burnell 0. Burritt, Detroit, Mich.

Application November 14, 1946, Serial No. 709,768 7 Claims. 01. 264 7) This invention relates to governor mechanisms, and more particularly, to mechanisms of the type known in the art as isochronous governor mechanisms for regulating the speed of prime movers and other controllable rotating mechanisms.

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 unaffected by dirt particles and air bubbles which render the usual forms of governors ineffective and inaccurate; to provide, in such a governor mechanism, 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 efiicient and accurate regulation of various types of engines; and to generally improve the construction and operation of governor mechanisms of the above generally indicated type.

With the above as well as other and, in certain casespmore detailed objects in view, which will become apparent from a consideration of the following specification and appended claims, preferred but illustrated embodiments of themvention 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 substan tially along the line 44 thereof.

It will be appreciated from a complete understanding of the present invention that, in a generic sense, the improvements thereof may be embodied in governor mechanisms of widely differing types and sizes adapted for use with numerous different types of prime movers or other operating mechanisms which it is desired to regulate. A preferred application of this invention is in connection with hydraulic governors of the type employing a hydraulic pump connected with a fluid motor through a pilot valve which is responsive to the speed of rotation of a flyball mechanism which is operatively connected to and responsive to speed changes of the prime mover to be'governed. In an illustrative, but

not in a limiting sense, except in so far as isdefined in the claims, the invention is so disclosed herein.

Referring to Figure l of the drawings, the governor mechanism is enclosed in a housing It and includes a gear pump generally designated l2, which employs a pair of meshing gears l4 and H3. The gear [4 is drivingly connected to a shaft [8 extending outwardly of the housing l0 and driven by, and responsive to, speed changes of the prime mover to be governed. The other gear [6 of the pump I2 is operatively connected to a shaft 20 which is journaled in a radially inwardly projecting boss 22 integrally formed on the casting It). At its upper end, the shaft 20 carriesa 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 30, which in turn drives a'gear 32 upon which is mounted a pair of flyballs 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, M), and 42, formed in the portion thereof disposed within the projection 22. Each of the annular passages 38, 40, and 42 communicates 58 carries apair of oppositely extending shafts Bi) and 62 secured thereto for reciprocation therewith. "The shaft 60 extends outwardly of the motor 54 and is adapted for connection to fuel or otherpower medium control means associated with the prime mover to'be governed. The oppositely extending shaft 62 projects into the housing I!) for cooperation with the governor compensating means which will be hereinafter described. The chamber 56 connects with the annular passage 49 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 H! mounted in the axial opening 36 of the valve sleeve 35 and having a portion I2 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 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 10 downwardly will establish communication between the ports 44 and the ports 46, thereby permitting pressure from the pump l2 to be applied to the motor through the line 50, the valve mechanism, and the line 54. Similarly, it will be apparent that a slight movement of the valve rod 10 in an upwardly direction from the position illustrated, will establish communication between the ports 46 and 48, thereby permitting the spring 66 is 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 14.

For controlling the axial position of the pilot valve 10, the fiyballs 34 are in the form of pivotally mounted bell cranks having inwardly extending arms 16 which engage a thrust washer 18 secured to the valve rod 10 for moving the valve rod in one direction. During operation of the governor, the centrifugal force urging the fiyballs 34 outwardly, acts through the lever arms 78 and the thrust washer 18 to urge the pilot valve 10 upwardly. This force is opposed by the downwardly acting force of a speeder spring 80, one end of which is anchored to the housing ID and the other end of which engages the upper end of the valve rod 10 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 structure 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 fiyballs 34, which are connected to the prime mover through the shaft IS, the gears 14 and 16, the shaft 29, and the

gears

24, 26, 28, 30 and 32. It will also be apparent that such a change in speed will disturb the balance between the force exerted on the valve rod 10 in one direction, by the fiyballs 34 acting against the thrust washer l8, 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 fiyballs 34 slow down correspondingly, reducing the centrifugal force acting thereon, and permitting the valve rod 19 to be pushed downwardly by the speeder spring 89. This downward movement of the valve rod I0, as described above, establishes communication between the ports 44 and 45,

thereby connecting the pump l2 to the line 54 and through it to the motor 54. This piston 53 is thereby moved upwardly, as viewed in Fig. l, causing the shaft 60 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 flyballs 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 fiyballs 34 would continue to increase, the fiyballs 34 moving outwardly as a result of the increased speed, and raising the valve rod 10 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 I0 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, 36 and 32, in addition to forming a part of the driving connection between the shaft l8 and the fiyballs 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 l0 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 98 of which is held in engagement with the upper end of the shaft 62 by a spring 52 anchored on the housing 10 and secured to the leg 88 of the bell crank. The relative proportions of these

gears

24, 26, 28 and 36 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, of the fiyballs 34 carried by the latter. It will also be apparent that the amount of rotation of the fiyballs 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 fiyballs is reversed by reversing the direction of movement of the arm 84. From the foregoing, it will be seen that when the gear 24 is being driven by the prime mover, as in normal operation of the governor mechanism, any pivotal movement of the arm 84 will introduce an artificial speed component causing the fiyballs 34 to, rotate at a speed other than that corresponding to the speed of the prime mover, and further it will be seen that during pivotal movement in one direction this component will act to increase the speed of the fiyballs relative to that of the prime mover, and during pivotal movement of the arm in the opposite direction it will act to decrease the speed of rotation of the fiyballs 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 fiyballs 34 will slow down disturbing the balance between the forces exerted on the valve rod by the fiyballs and the speeder spring and permitting the speeder spring 80 to force the valve rod 70 downwardly with the consequent amplication of hydraulic pressure to the piston 58 described above. This hydrauli pressure forces the piston 58 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 cf the prime mover. Also during this upward movement of the piston 58, the upwardly extending shaft 62 engages the leg 90 of the pivotally mount-ed bell crank 83 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. 1, and increases. the speed of rotation of the fiyballs 34. The amount of this artificially produced component of the speed of the fiyballs 3:! 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 fiyballs, they resume their initial position and the valve rod closes the port 44, thereby stopping the application of pressure to the motor 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 ever-shooting and hunting can be accomplished only by balancing the individual governor mechanism to the particular prime mover upon which it is installed. This 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 different 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 fiyballs 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 theshaft 62, carried by the piston 58, acts. In this manner, the artificially induced component of the speed of the fiyballs 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 setting 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.

Similarly, when the prime mover speeds up because of a reduction in its load, the flyballs move outwardly, raising the valve rod and permitting a downward movement of the piston 58 and the flow of fluid from the motor 54 into the housing I0. 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. 1, producing an artificial decrease in the speed of the fiyballs and a correspondingly early return of the fiyballs 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 over-shooting or hunting.

Numerous attempts have been made in the past to 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 difficulty has been encountered in building such springs because of the'nature of the forces acting against them. As in'dicated'above', the speeder spring acts against the valve-"rod-to urge it in one direction and the centrifugal force of the fiyballs acts through the arms 'lfi'to urge it in the opposite direction. This centrifugal forces varies directly with the square of the speed of rotation of the fiyballs and also varies directly with the radius of rotation of the fiyballs. The latter, of course, is important only duringthe intervals in which the fiyballs 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 fiyball 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 ap" proached. These springs, however, are extremely difficult and expensive to manufacture withthe desired accuracy.

The present invention attains the desired highly sensitive regulation throughout the speed range by the use of the speeder spring mechanism illustrated in Figure 1. This mechanism comprises a flat spring strip 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 0. The other end of the spring strip 88 engages the upper end of the valverod Hi to urge the later in a downward direction in opposition to the centrifual force of the fiyballs transmitted thereto as above described.

The pressure of the spring strip 8!! against the valve rod 10, 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 86 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 I08, the other end of which is pivotally supported on the housing It by a bolt I02 or any other suitable means. The lever I00 is held in adjusted position between a pair of opposed set screws I04 supported inand having a threaded engagement with ears I93 inte rally formed on or otherwise suitably carried by the housing I0. The purpose of this adjustment will be hereinafter described.

The link 98 is pivotable about its above-mentioned connection to the lever I 00, and is held at the desired setting by means of a crank I08 pivotally mounted on the housing i and connected to and operable by suitable handle means disposed externally of the housing. The crank I08 is connected to the link 98 by a tie rod IIO 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 I08. It will be apparent from the above-described structure that movement of the crank 08 in a counterclockwise direction, as viewed in Fig. 1, will cause the roller 06 to move downwardly and to the left in a circular are about the pivotal connection of the link 98 and the lever I00. 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 different 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 I04 which control the position of the lever I00 and therefore of the are along which the roller 95 moves when the speed setting of the governor is changed. The lever I00 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 Figure 2, in which the above described speeder spring mechanism is replaced by a conventional coil spring I20 of the above-mentioned type in which the diameter and pitch of the coils vary. The lower end of the spring I20 seats on the upper surface of a washer I22, corresponding to the washer I8 of the previously described embodiment, and pressure is applied to the upper end thereof through a vertically disposed head I24 which engages the upper end of the spring. The head I24 is pivotally mounted in the outer end of a crank I23, 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 modmed driving mechanism comprises a pair of coaxial shafts I30 and I32, one of which corresponds to the shaft 20 and the other or which is adapted to carry a gear (not shown) corresponding to the gear 30. The adiacent ends of the shafts I30 and I32 carry spaced, parallel, and opposed, bevel gears I34 and I36, respectively, which are drivingly interconnected by a third bevel gear I38 rotatably supported on a shaft I40 disposed at right angles to the coaxial shafts I30 and I32.

A hollow T section I42 is disposed intermediate the gears I34 and I36 and journals the adjacent ends of the shafts I30 and I32. The inner end of the shaft I40 extends into the remaining branch of the hollow T section I42, and the shaft I40 is supported thereby as a cantilever. At its outer end the shaft I40 carries a ring gear I44 coaxial with said shafts I30 and I32 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 I44 corresponds to the lever 84 of the embodiment illustrated in Figure 1, and that when the shaft I30 is held stationary, rotary movement of the ring gear I44 will likewise rotate the fiyballs, which are connected to the shaft I32, in the same manner as the abovedescribed movement of the lever 84 in that em- 'bodiment.

In the embodiment illustrated in Figures 3 and 4, rotary movement is imparted to the ring gear I44 in response to the movement of the piston I45 of the fluid motor, by the engagement of the ring gear I44 and a rack I 46 carried by a shaft I 48, 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. a

What is claimed is:

1. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, a source of fluid under pressure, means connecting said source to said servomotor and including a valve element movable in either direction from a neutral positon for controlling the operation of the servomotor, speed setting means urging said element in one direction, a rotary element operatively connected to said valve element for urging the latter in the opposite direction with a force proportional to the speed 015 said rotary element, drive means for connecting said rotary element to said associated mechanism for rotation at a speed proportional to the speed of said associated mechanism, and means operatively connecting said servomotor and said drive means and operable to vary the driving ratio of said drive means during operation of the servomotor.

2. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, a source of fluid under pressure, means connecting said source to said servomotor and including a valve element movabl in either direction from a neutral position for controlling the operation of the servomotor, speed setting means urging said element in one direction, a rotary element operatively connected to said valve element for urging the latter in the opposite direction with a force proportional to the speed of said rotary element, drive means for connecting said rotary element to said associated mechanism for rotation at a speed proportional to the speed of said associated mechanism, said drive means including a train of gears and means mounting certain of said gears for bodily movement without interrupting the drive through said train of gears. and means operable by said servomotor and engaging said means mounting certain of said gears for moving the latter and varying the driving ratio of said drive means during operation of said servomotor.

3. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, a source of fluid under pressure, means connecting said source to said servomotor and including a valve element movable in either direction from a neutral position for controlling the operation of the servomotor, speed setting means urging said element in one direction, a ro- 1 tary element operatively connected to said valve element for urging the latter in the opposite direction with a force proportional to the speed of said rotary element, drive means for connecting said rotary element to said associated mechanism for rotation at a speed proportional to the speed of said associated mechanism, said drive means including a train of gears and means mounting certain of said gears for bodily movement without interrupting the drive through said train of gears, and means operable by said servomotor and engaging said means mounting certain of said gears for moving the latter and varying the driving ratio of said drive means during operation of said servomotor, said last named means comprising a pivotally mounted bell crank one arm of which is connected to said servomotor for movement thereby and the other arm of which engages said means movably mounting certain of said gears.

4. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, speed setting means to condition the apparatus to establish a desired speed of said associated mechanism, a rotary element, variable drive ratio driving means for connecting said element to said mechanism for rotation at a speed proportional to the speed of said mechanism, said driving means including a member movable to vary the drive ratio of said driving means, mean for controlling said servomotor in response to the relation between the actual speed of said rotary element and the speed thereof corresponding to the desired speed of said mechanism, and means connecting said servomotor to said member of said driving means so that operation of said servomotor is effective to move said member to vary the driving ratio of said driving means during the period of operation of said servomotor.

5. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, speed setting means to condition the apparatus to establish a desired speed of said associated mechanism, a rotary element, variable drive ratio driving means for connecting said element to said mechanism for rotation at a speed proportional to the speed of said mechanism, said driving means including a member movable to vary the drive ratio of said driving means, means for controlling said servomotor in response to the relation between the actual speed of said rotary element and the speed thereof corresponding to the desired speed of said mechanism, and mechanical means directly connecting said member of said servomotor to said driving means so that operation of said servomotor is efiective to move said member to vary the driving ratio of said driving means during the period of operation of the servomotor.

6. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, speed setting means to condition the apparatus to establish a desired speed of said associated mechanism, a rotary element, variable drive ratio driving means for connecting said element to said mechanism for rotation at a speed proportional to the speed of said mechanism, said driving means including a member movable to vary the drive ratio of said driving means, means for controlling said servomotor in response to the relation between the actual speed of said rotary element and the speed thereof corresponding to the desired speed of said mechanism, and mechanical means directly connecting said servomotorto said member of said driving means so that operation of said servomotor is effective to move said member to vary the driving ratio of said driving means during the period of operation of the servomotor, said last named means comprising a pivotally mounted bell crank one arm of which is connected to said servomotor for movement thereby and the other arm of which engages said drive means.

7. An apparatus for governing the speed of an associated mechanism, said apparatus comprising a servomotor adapted to actuate the throttle or other power medium control of the associated mechanism, a source of fluid under pressure, means connecting said source to said servomotor and including a valve element movable in either direction from a neutral position for controlling the operation of the servomotor, speed setting means urging said element in one direction, a rotary element operatively connected to said valve element for urging the latter in the opposite direction with a force proportional to the speed of .said rotary element, drive means for connecting said rotary element to said associated mechanism for rotation at a speed proportional to the speed of said associated mechanism, and means for varying the driving ratio of said drive means during operation of said servomotor.

BURNELL O. BURRITT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number