US2301348A - Speed governor for engines - Google Patents

Description

1942- A. G. F. WALLGREN ErAL 2,301,348

SPEED GOVERNOR FOR ENGINES Filed Dec. 21, 1959 2 Sheets-Sheet 1 1942- A. G. F. WALLGREN ETAL 2,301,348

SPEED GOVERNOR FOR ENGINES I Filed Dec. 21, 1939 2 Sheets-Sheet 2 W g Wa Patented Nov. 10, 1942 SPEED GOVERNOR For: ENGINES August Gunnar Ferdinand Wallgren, Eslgilstuna,

and Gunnar Seligman, Stockholm, Sweden, as"

signors to Aktiebolaget Boll'ndeif Munktell,

Eskilstuna, Sweden, a corporation of Sweden Application December 21, 1 939, SerialNo. 310,356 In Sweden January 4,1939

6 Claims.

This invention refers to governors for engines, such as steam engines, steam and hydraulic turbines, internal combustion motors and the like, which are provided with members, for instance valves, adjustable guide blades, or fuel pumps for the control of the supply of energy medium to the power engine. The governors serve directly or indirectly to actuate these mem bers so that the speed of rotation of the engines will be maintained constant or approximately constant, or will be adjustable at varying load.

It is one object of the invention to provide a noveltype of governor, in which metallic friction 'has been obviated to a large extent and which is superior to governors hitherto in use as regards sensitivity and wear. Another object of the invention is to provide a governor which is simple in construction and consists of a small number of parts, so that it is considerably cheaper than the known governors. A further object of the invention is to provide a governor which is more safe in operation than the known governors.

Further and more detailed objects of the invention, together with the manner in which they and the above stated objects are attained, may best be understood from a consideration of thefollowing description of the invention as embodied in suitable forms of machines, taken in conjunction with the accompanying drawings, forming a part of this specification, of which: 7

Fig. 1' shows more or less diagrammatically, and in a perspective view, a governor according to the invention;

Fig. 2 shows in a perspective view a modified detail of the governor according to Fig. 1;

Fig. 3 shows a perspective View of another governor according to the invention;

Fig. 4 shows a curve indicating the alteration of the adjusting power as generated'in'a governor according to the invention, with the speed of the engine;

Fig. 5 shows a section taken on the line V-V' of Fig. 6 through a still further embodiment of a governor according to the invention;

Fig. 6 is a'section'on the line VIVI of Fig. 5.

In the various figures, corresponding parts have been denoted by the same reference numerals. In Fig. 1, 20 designates a shaft, the number of revolutions of which is dependent on the number of revolutions of the'driving shaft of the engine. The shaft 20 drives through a gearing an armature in the form of a cylindrical an engine.

permanent magnet 50, a suitable gap being provided between the two elements. The magnet 50 is preferably of a material having a great quantity of magnetic energy and being nonsensitive to shocks and high temperatures. To this end Al-Ni alloyed steel, for example, is to be preferred to ordinary carbon steel. on rotation of the ring 51 a turning moment will be produced on the permanent steel magnet 50 which is rotatably mounted on a shaft 52 coinciding with the axis of the armature. From the. shaft 52, this turning moment is transmitted either directly to a control member 21 or over a; device as will be described in the following. The member 2! may be a' throttle valve in a conduit 28' for the supply of driving medium to A shaft 5,4 carrying the movable member of the valve 21 is" through one or more links 35" connected to a spring 29.

The spring 29 counterbalances the turning momentproduced on rotation of the magnet 50. The spring Z9 is so dimensioned that equilibrium will'beprod'uced between the spring tension and the turning moment in a position of the valve 21in which the supply of driving medium' to the engine corresponds to'normal number of revolutions at normal load. If the number of revolutions of the engine increases, the turning moment or; torque will rise, the valve 21 being then fihIOtiZlBdySO; that the supply of driving mediumis diminishedyand the. engine isagain caused to approach the initial speed. At a decrease of the speed of the engine, the turning moment willfall, the spring tensionthen overweighingso as to open-the valve 2'l'so' that the supply of driving medium is increased and the number of revolutions of the engine rises towards the normal one. The number of revolutionsat which a balance sets in between the torque of the' armature 50 and the moment of thespring 29; that is ,to' say, the number of revolutions to which the engine is regulated by the governor, may .be adjusted by changing the tension of the spring.

An engine, for instance an internal combustion motor, may be intentionally or unintentionally reversed. In case of intentional reversing or backward running,-the shaft '52 maybe connected directly to the shaft 54. It is then only necessary to have the spring 29 to give the same tension in both turning directions of the adjusting member. Unintentional reversing may occur in motors constructed merely for on'edi rection of" rotation, for instance, on account of ring 5| of-soft iron. The ring 5| surrounds a aniincorrect' assembly of the motor, so that'preq mature ignition sets in. In order to protect such engine against dangerous speeds at unintentional reversing through too ample a supply of driving medium, an auxiliary throttle member 53 may be used, which is inserted in series with the control member 21 in the conduit 28 for the driving medium. The permanent magnet 56 serving as adjusting member is not connected directly to the shaft 54 actuating the control. member 2'! and being under the influence of the spring 29, but the torque of the shaft 52 is transmitted to the shaft 54 through an arm 55 having a pin 55, and through an arm56 or the like, which are rigidly connected with the respective shafts. The pin 58 is not connected to the arm 56 but only abuts thereagainst on normal operation of the governor. When the enimparts to the governor a difierent controlling character, if the same remains constant during the controlling movement, or if it is increased or decreased. On account of the special properties of a spring, there are to some extent restricted possibilities available for the automatic variation of the moment during the controlling movement. If the spring be replaced by a magnetically operating device, as shown in Fig. 3,

gine stops, the spring 29 moves the control member 2'! into its fully open position wherein it stops against a fixed abutment 35'. justing member 55, which when stationary has no torque, is then free to move further therefrom by a certain angle in the same direction, without the control member 21 being actuated. Should the impulse member 5| be driven in a direction opposed to that intended for normal operation, the adjusting member will be subjected to a moment in this direction corresponding to the rotational speed, the pin 58 thus actuating another arm 59 secured on a shaft 69 which enters the throttle member 53. Shaft 6|] is provided with an arm 35a to which is connected a spring 29a tending to turn the shaft 66 in a direction opening the valve 53. A stop 35a is provided for holding the shaft in the full open position of the valve. Rotation of the shaft 60 against the force of spring 290. actuates the valve 53 so that the supply of driving medium through said conduit is diminished or cut off, or some other member will be actuated, which may cause the power engine to slow down or stop. If the cut-01f member 53 be made easily actuated relatively to the turning moment of the adjusting member 56, as by making the spring 29a relatively light, such operation may take plate at a comparatively low number of revolutions of the power engine.

The steel magnet 50 may alternatively form the impulse member while the armature 5| is the adjusting member. In this case the permanent steel magnet may be formed asa ring sur- The ad rounding an armature made from soft iron.

Also, the external element 5| need not be made as an enclosing ring, and otherwise the magnet as well as the armature may be given any suitable form known per se from the art of magnets.

Fig. 2 shows a modification of a device for allowing reversal of the direction of rotation of the engine. On normal operation of the engine, the shaft 52 of the adjusting member actuates the control member 21 over the links 55, 58 and 56 in the same manner as in Fig. 1. At backward running, however, the torque of the adjusting member is transmitted to a link 59 which, in turn, causes the control member to be turned in one and the same turning direction as on normal operation, for instance through an arm 84, a rod 85, and a link 86 arranged on the shaft 54. In this case, the requisite control of the supply of driving m dium will thus be obtained by a single member in the driving medium conduit 28.

In the embodiments above described, the adjustable torque balancing the adjusting member is effected by means of a spring. 'This torque the moment values thereof within the required ranges of speeds may be caused to follow any desired curve relatively to the corresponding values of the adjusting member, as will be explained more in detail in connection with Fig. 4 so that the governor will always obtain the controlling character aimed at with respect to rapidity and sensitivity Within different ranges of speeds. The said device may consist of a permanent magnet 6| which is connected by a shaft 62 to the controlling member 21 and to the shaft 52 of the adjusting member 56. The magnet 6| is surrounded by a cylindrical ring 63 which is driven over a gearing 64 from the same shaft 20 as the armature 5|, but in opposite direction to the latter. The device 6|, 63 is of the same kind as the members 56, 5| although the turning moments produced by the same are directed oppositely relatively to each other. Also, the gear on shaft 20 which drives ring 63 is of greater diameter than the corersponding gear for driving ring. 5|, whereby ring 63 rotates at a higher speed than does ring 5|.

A control of the strength of the turning moment in the device 6|, 63 according to Fig. 3 may be effected, for example, by the two elements 6|, 63 being axially displaceable relatively to each other. The surfaces of the elements facing one another may be conical so that the air gap therebetween is increased or decreased at such displacement. This also holds true with respect to the governor members 50, 5|.

In all embodiments, the alteration of the torque of the adjusting member, in other words the alteration of the adjusting power, follows a curve 65, as will appear from Fig. 4, relatively to the speed of the engine. In the said figure, the horizontal X-axis represents the speed and the vertical Y-axis the torque. As will be seen from Fig. 4, the adjusting power is zero when the speed is naught. The adjusting power curve 65 rises from this zero value until at a certain speed it forms a more or less pronounced knee at a maximum value of the adjusting power, and may then extend in different ways at different dimensionings, as indicated by dotted lines. It is of essential importance for the invention that the rotational speed be given such a value that the adjusting power within a sufficient range of numbers of revolutions increases and decreases materially with an increased or decreased speed, that is to say, that the portion of the adjusting power curve having a sufficiently steep rise is made use of. This portion may consist, for instance, of the range of speed designated in the figure by a.

In Fig. 4, three lines 86, 8|, B2 are shown, which represent diagrammatically different conceivable possibilities for the vibration of the power or torque of the counter-balancing element atthe speeds in question. The curves -82 are imagined to intersect curve 65 at point 83 within or at the centre of the range of speeds a. The curve 80 rises with the speed and the vertical Y-distance between this curve and curve 65 represents on both sides of'point 83 the magnitude of the adjusting power at different speeds exerted by the adjusting member on the control member. The curve 8| is imagined to extend parallel to the X-axis. It will be understood that the vertical distances, that is to say the adjusting powers, increase more rapidly when the speed of the power engine leaves point 83. Inasmuch as the curve 82 falls with an increased speed, the adjusting powers must become still greater at a certain change of the speed than in the two other cases. The curve 80 may be said to represent the power or turning moment in the case of a spring. By making this spring of sufficient length, the curve 81 may be approached. With a counterbalancing device according to Fig. 3, torque curves 80, 8| may be obtained, and it is even possible to reach a curve 82 with possibilities in consequence thereto to obtain the requisite adjusting power for'smaller alterations of speed. Curve 8!] may be obtained by the device shown in Fig, 3, if the gearing is so designed that the speed of ring 63 is sufliciently greater than that of ring so that the coupling 6|, 63 is operating on the bent portion of curve 65 while the coupling 5B, 51 is operating on the straight inclined portion between the lines a. Curves 8| and 82 are obtainable if the gearing is designed so as to give the ring 63 a still higher speed so that the coupling BI, 63 operates in the broken line portion of the curve 65 beyond the bend, curve 8| being obtained if the speed-torque curve remains-horizontal, while curve 82 is obtained if the torque decreases with an increase of speed.

Figs. 5 and 6 illustrate a constructive embodiment of a governor according to the invention. The driving shaft of the governor is designated by 20, as before, and is journalled in the casing of the governor by means of ball bearings 66, 61, or the like. A pinion 68 secured to the shaft drives a gear 69 of non-magnetic material, such as brass. This gear wheel 69 is mounted on a rigid sleeve H by means of a bearing It. The gear wheel 69 carries an armature 5| in the form of a cylindrical ring from soft iron. The

' ring 5| is supported on one side thereof by a non-magnetic element 12 mounted in a rigid sleeve 14 by means of a bearing 13. A permanent steel magnet 50 is provided inside the ring 5| and between the parts 69 and 12, the magnet with its shaft 52 being then rotatably mounted in bearings l5, 16. The shaft 52 is connected in turn to a control member 21 and a spring 29, or with a magnetic device according to Fig. 3 as above described.

The member 5| of soft iron may be provided with a preferably short-circuited winding, among other things for the purpose of giving the adjusting power curve 65 (Fig. 4) suitable'form. In Figs. 5, 6, this winding is constituted by copper bars 19 extending axially through the armature 5i and being in electrically conducting connection with the brass rings 69, 12.

The invention is not limited to the subject matters of the description hereinbefore but may be varied in many respects, without the principle of the invention being departed from. The number of revolutions of the engine may happen to vary during one revolution, and. to prevent the control member at such alterations of the speed, if not desired, from being brought into function, weights or the like may be arranged on the shaft connected with the adjusting member, said weights then causing damping of the movements of the member. A governor according to the 1nvention may be used in combination with a socalled racing governor adapted to open the motor cylinders, so that compression cannot be effected. Such a racing governor is necessary at all kinds of governors for motors which may be driven unintentionally by other means than by the ordinary driving medium, for-instance by the lubricating oil in certain types of internal combustion motors.

In certain cases the magnetic field may instead of by a permanent magnet be produced by an electro-magnet, either forming the rotating or the relatively stationary part of the governor. This electro-magnet is then fed with direct current through wires from a separate and constant source of current. Such embodiments are, however, more complicated and not as safe in operation as those described above in connection with the figures.

In power engines, such as hydraulic turbines, which require great adjustingforces for the shifting of the control member, the magnetic governor may obviously be arranged in known manner only to actuate an electric contact system or other impulse member for a so-called servomotor, instead of actuating the control member directly, said servo-motor performing, in turn,

the actual adjusting work.

What I claimv is:

1. In a governor for actuating the speed control device of an engine, a rotatably mounted annular ring of magnetic material, a short circuited winding carried by said ring, means for rotating said ring at a speed proportionate to that of the engine, an armature of magnetic material turnably mounted concentrically Within said ring so as to receive a turning moment proportional to the speed of the ring, means for yieldably resisting actuation of said device in a direction decreasing the speed of the engine, and means operatively connecting said armature with said device whereby rotation of said armature in either direction as a result of increase in speed of said impulse member actuates said control device against the resistance of said yieldable means to decrease the speed of the engine.

2. In a governor for actuating the speed control device of a reversible engine, a rotatably mounted impulse member, means for rotating said member in the same direction as and at a speed proportionate to that of the engine, a turnably mounted adjusting member magnetically coupled to said impulse member so as to receive a turning moment in the same direction as and proportional to the speed of the impulse member, said control device including two control members either of which is independently operable to reduce the speed of the engine, means for yieldably resisting actuation of each of said control members in a direction decreasing the speed of the engine, means operatively connecting said adjusting member to one of said control members whereby rotation of said adjusting member in one direction as a result of increase in speed of said impulse member actuates said one control member to decrease the speed of the engine, and means operatively connecting said adjusting member to the other of said control members whereby rotation of said adjusting member in a direction opposite to the aforesaid as a result of increase in speed of said impulse member actuates said other control member to decrease the speed of the engine.

3, In a governor for actuating the speed 0011-! trol device of a reversible engine, a rotatably mounted annular ring of magnetic material, a short circuited winding carried by said ring, means for rotating said ring in the same direction as and at a speed proportionate to that of the engine, an armature of magnetic material turnably mounted concentrically within said ring so as to receive a turning moment in the same direction as and proportional to the speed of the ring, said control device including a control member movable in one direction to increase the speed of the engine and movable in the opposite direction to decrease the speed of the engine, yieldable means for resisting movement of the control member in the last mentioned direction, and means operatively connecting said armature with said control member whereby rotation of said armature in either direction as a result of increase in speed of said impulse member moves said control member in a direction against the resistance of said yieldable means to decrease the speed of the engine.

4. In a governor for actuating the speed control device of an engine, a rotatably mounted impulse member, means for rotating said memher at a speed proportionate to that of the engine, said speed control device including an element turnable in one direction to increase the speed of the engine and turnable in the opposite direction to decrease the speed of the engine, an adjusting member connected to said element and magnetically coupled to said impulse member so as to receive a turning moment directly proportionate to the speed of the impulse member, and means'for yieldably resisting turning of said element'under the influence of said turning moment including a second adjusting member connected to said element, a second impulse member magnetically coupled therewith, and means for rotating said second impulse member at a speed proportionate to the speed of the engine but at a higher speed than and in the opposite direction from the first mentioned impulse memher.

5. A device as set forth in claim 4 including means for varying the air gap between one of the impulse members and the associated adjusting member.

6. In a governor for actuating the speed control valve mechanism of an engine, a rotatably mounted annular ring of magnetic material, a short circuited winding carried by said ring, means for rotating said ring at a speed proportionate to that of the engine, an armature of magnetic material turnably mounted concentrically within said ring so as to receive a turning moment proportional to the'speed of the ring, means connecting said armature to said valve mechanism for direct operation of the latter by the former, and means for yieldably resisting actuation of said mechanism in a direction decreasing the speed of the engine.

AUGUST GUNNAR FERDINAND WALLGREN. GUNNAR SELIGMAN.

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