US2313206A

US2313206A - Impulse neutralizer

Info

Publication number: US2313206A
Application number: US284945A
Authority: US
Inventors: Sarazin Raoul Roland Raymond
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-08-05
Filing date: 1939-07-17
Publication date: 1943-03-09
Anticipated expiration: 1960-03-09
Also published as: FR50959E; US2156484A; BE436544A; FR841736A; GB541445A; GB506584A; BE429511A

Description

`MarchQ, -1943. v R. R. sARAzlN 2,313,206

IMPULSE NEUTRALI ZER FiledlJuly 17, 1939 2 Sheets-Sheet 2 A tor-nega Patented Mar. 9, 1943 v 2,313,206Il IMPULSE NEUTRALIZER Raoul inland Ramona sarazin, samt-Prix, France: *vested in the Alien Property Custof Application July 17, `193s), serial No. 284345' In Luxemburg July 25, 1938 11 Claims. (Cl. 74-604) The present invention relates to devices for imparting impulses to a system. It ismore especially, although not-exclusively, concerned with devices of this kind for imparting impulses, with a viewto at least partly lensuring the balancing of its kinematic cooperating means, to the crankshaft of analternating machine, such as an internal combustion engine having its cylinders disposed in fan-like arrangement, with two or more branches, or in simple or multiple radial arrangement, and more especially an engine the kine-- matic system of which includes the combination of a main connection rod and other connecting rods.

In -a prior patent, No. 2,156,484, I described a device for reducing the vibrations of a system including a rotating element, these vibrations being due to a pulsatory force acting on said elementand rotating at the same speed of revolution as the element in question, this device including alpendularsystein constituted by atleast two pendulums pivoted to the rotating element pulsatory force and coacting with la device ca-` pable of controlling the oscillation of the pendulums on either side of their radial position.

The chief object of the present invention is to provide a device of the type above described which is better adapted to meet the requirements of practice than those used for the same purpose up to the present time, and, in particular, simpler than up to now.

According to an essential feature of the present invention, in order to reduce the vibrations of a system including a rotating element or strucing a rotary element or structure, this assembly 'I being subjected to the action of a pulsatory force of order n with reference to the rotary structure (that is to say having n pulsations per revolution of the rotary structure) and of a pulsatory torque of the same order, makinga certain angle with. said force, the latter turning at the same speed as the rotary structure. feature consists in making use, for balancing boththis force and this torque, of a pendular system carried by said rotary structure and urged back toward its neutral position by the centrifugal force created by the rotation of said structure, this pendular i system being constituted by at 'least two penduon either side ofthe radial plane containing said ture, this'systern being subjected to the action g of a pulsatory force turning at the same rate as this rotating element or structure, I make use, in order to balance this force, of a free pendular system -(that is to say a system independent of any control meansl, this system being carried by'said rotary structure and being urged back toward its neutral position merely by' the centrifugal force created by the rotation of this structure, this pendular system being constituted by at least two pendulums pivoted to therotary structure on either side of the radial plane containing said pulsatory force and adapted to' oscillate, with their natural frequency, so as to make, for every revolution of the rotary structure, as many complete beats as there are pulsations oi' the pulsatory force.

Another feature 4of the present invention relates to the case in which it is desired to reduce the oscillations of a system or assembly-includa modlcation of the device accoring to the result from the following detailed description of some specific embodiments thereofi way of example, and in which:

Fig. 1 is a diagrammatical view illustrating the principle of the invention when it is desired to .reduce or to compensate a rotary pulsatory force.

Fig. 2 is a diagrammatical view illustrating the principle ofthe invention when it is desired to reduce both a rotary pulsatory force and a pulsatory torque of the same order making a certain angle with said force;

Fig. 3 is a diagram showing the perturbing forces which are produced in the case of a sys-v tem including a main connecting rod and at least one other connecting rod associated therewith;

Fig. 4 diagrammatically shows, in end view, the crankshaft and the connecting rod system of a radial engine With a master connecting rod and auxiliary rods associated therewith', this system being provided with balancing means acvcording to the present invention;

4. pres- Fig. 5 shows, in a. manner similar to Fig.

ent invention;

Fig. 6 is `a diagrammatical view showingmin perspective a system similar to that of Fig. 5

but including a crankshaft with two opposed crank arms;

Fig. 7 shows, in a manner similar to Fig. 4, a

Vmodication of the device illustrated by Fig. 6;

Preferred embodiments of the present inven-l Ation will be hereinafter described, with reference to the accompanying drawings, given merely by l Fig. 8 diagrammatically shows a crankshaft with two opposed crank arms, provided with means made according to the embodiment of Fig. 7;

Finally, Fig. 9 shows, in a manner similar to Fig. 4, a modification of the device according to Fig. 7.

According to the invention, itis desired to provide a device for imparting impulses to a system including a rotary structure, for instance a crankshaft, with a view to compensating, at

least partly, for a rotary pulsatory force of order n, that is to say having n` periods for every revolution of the rotary structure v (see Fig. 1) and carried by a radial vector OX which turns together with the rotary structure about the axis O thereof.

Ivmake use of at least one pendular system which is carried by said rotary structure or by an element associated with said structure, this system including, on either side of the radial plane- OX, two free pendulums p, p" urged back toward their neutral position merely by the centrifugal force created by 'the rotation of this element, these pendulums being arranged in such manner as to oscillate in planes at right angles to the axis O of rotation of the rotary structure and having a natural-frequency of' order n,.that is to say having, same as the rotary pulsatory force, n periods per revolution of the rotary structure.

The axes of articulation Il and I' of pendulums p and p', which are parallel to axis O, will be located preferably in symmetrical relation with reference to axis O in a plane DD' perpenthrough said axis.

of rotation of the rotary structure, on the other hand, makewith each other an angle different from 180 so that the pendulums do not only communicate to rotary structure v a pulsatory radial force of order n, but also a pulsatory torque of the same order, with a dephasing of a certain angle with respect to said force and coaxial With saidrotating element or structure 1.1, said force and said torque being capable of simultaneously compensating a perturbing force and a corresponding perturbing torque.

The dephasing between the rotating pulsatory force and the pulsatory torque determines the angle between radiuses OI and OI', or angle 0, the latter being the angle made respectively between said radiuses and the plane DD passing through axis 0, respectively. When the dephasing between the pulsations of the rotary force and the torque is equal to 90, angle 0 is preferably equal to which permits of obtaining the most accurate results.

If, in the embodiment according -to Fig. 2, the rotary structure v is subjected simultaneously to the action of a rotating pulsatory perturbing force and a pulsatory torque, of the same frequency as said force but shifted inphase With respect'to the latter, pendulums p and 'p' are automatically' set into oscillation, with a dephasing of 180 more or less an angle p for thus creating the compensating force and the compensating torque. h

It has been supposed, for thesake of simplicity, that the compensating pendulums were of the monolar type, but obviously this is not When such a system is in operation, it is found that these pendulums assume by themselrves movements such that they remain constantly out of phase with respect to each other by one half of a period, that is to say that they remain always, at a given time, on the same side of plane DD'.

Considering then these pendulums whJenthey pass through their positions corresponding vto the maximum of the angles they make with their positions of equilibrium (position shown by the drawings), itis found that these forces are two forces F and F symmetrical with'respect to OX so that their projections on this direction will be added to each other at any time in absolute value, the resultant of these projections being a pulsatory force of the same period` as said pendulums.

Therefore, it will be readilyunderstood that it is possible, by suitably choosing the masses of pendulums p and p', to arrangethat this resultant is constantly substantially equal in intensity and opposed in direction to the perturbing pulsatory force to be compensated.

In the device according to Fig. 1, the two pendulums p and p are connected together through suitable means, for instance connecting rods I4 pivoted tongers carried, by the pendulums, said connecting means compelling the pendulums to oscillate with lthe desired de-phasing with respect to each other, but it should be noted that lthese connecting means are not at all necessary.

In the device according to Fig. 2, the axes of articulation l, l' of pendulums p, p', instead of being located in a plane passing through axis O, are located in a plane Da-Da perpendicular to vector OX and located at a certain distance from axis O. The radiuses passing respectively through the axes of articulation of the two pendulums, on theone hand, and through the axis which occur in a radial cylinder including a sys-l tem of connecting rods constituted by a master connecting rod witha head 3 to which the heads of connecting rods 4 are pivoted about axes 5 distinct-from the axis of crank pin 6 (s'ee Figs. 4 to 9).

It is known that such a system applies to the crank pin a force F (Fig. 3) of constant value, making with thecr'ank radius an angle a. equal to, and in the same direction as, the angle made by said crank radius with the axis O'X' on' which moves the other end of the master 4con-- ,necti'ng rod. This is trl'le if said axis is radial and very close to.the truth in the other cases which are practically met with.

This force F may be decomposed into two other forces, one of which is a radial force F c os a and the other a force perpendicular to the crank radius, to wit, F sin q.

The first mentioned force is a radial pulsatory. force carried by vector O'X', which turns together Iwith the crankshaft, with the same speed as the latter, and is of a. frequency equal to the speed of revolution of the crankshaft, that is to say ofv order 1, whereas the other force produces a pulsatory torque of 'axis O and also,`

of order 1 with respect to the speed of revolumovements of which are produced and maintained exclusively by the e'ect of said perturbations on the crankshaft.

According to the embodiment illustrated by Fig. 4,' I provide, in order to reduce the perturbing pulsatory force of order 1, two pendulums p, p' pivoted to the crankshaft about axes I and I', these axes being located in a plane DD' perpendicular to vector O'X' and passing preferably through axis O'. The natural frequency of pendulums p, p' is chosen in such manner that they make a complete oscillation for every revolution of the crankshaft.` Pendulums p, p' impart to the crankshaft a compensating force which is substantially equal and opposed to the rotary force F cos a whereby these two forces mutually destroy each other, at least substantially.

In order to reduce the perturbing pulsatory torque, I have recourse, according to Fig. 4, to a single pendulum, pivoted to the crankshaft on the side of the crank pin, this pendulum being preferably mounted in such manner as to oscillate about the very axis of the crank pin, for which purpose it is advantageously made of the bifilar form, its mass I being suspended through two connecting rods I6 and I1 to two axes carried on either side of one of the cheeks of the crank pin.

The natural frequency of this last mentioned pendulum is also of order 1 with respect to the speed of the crankshaft.

Of course, the mass of this last mentioned.

pendulum is balanced by a suitable increase of the mass of the usual counterweight of the crank pin.

This embodimentV constitutes an accurate solution of the. problem, but its application to engines of the usual types produces, in some cases, difficulties which are chiefly due to the lack of room for housing, on the one hand, the third pendulum I5, and. on the other hand, the normal counterweight, the size of which is to be increased so as to balance the mass of the pendulum in question.

In order to avoid this dimculty, I pivot, in the arrangement according to Fig., 5, said third pen- "adulum to the crankshaft at a point located on ,the other side from the crank pin with respect 'to the axis of revolution of the crankshaft.

Of course, such a pendulum system leaves cersystem the natural frequency of which corresponds, for every revolution of the crankshaft, to a number n of complete oscillations equal to one half of the number of cylinders, the first pendular system may be carried by a crank arm and the second by another crank arm.

This may be the'case as well when the crankshaftl has a single bend as when it has several bends.V

In the second case, the pendular system made according to the invention, instead of partly balancing the force P above mentioned, partly balances .the torque constituted by the two forces F, equal and of opposed directions, created by the two systems of connecting rodsv including a master connecting rod and a plurality of auxiliary lOdS.

Thus, although it is possible to make use of a distinct pendular system for eachv bend of the crankshaft, it is also possible, as shown by Fig. 6, to utilize only a single pendular system of order l for the whole of the crankshaft.

It isthen advantageous to mount this system on the front crank arm of the crankshaft, on the side of propeller I9, whereas the pendular system 20 of order n is mounted on the rear crank arm.

According to another embodiment of the invention (Figs. '7 to 9) which is also more particularly applicable to .the case of a system including a master connecting rod and at least one secondary rod, I make use of an arrangement similar to that diagrammatically shown by Fig. 2 for compensating simultaneously, and by means of Yonly two pendulums, as well the pulsatory radial per-v tunbing force as the pulsatory perturbing torque.- In order to obtain this result, I pivot the pendulums p and p above described about axes I and I' preferably located in a plane Da, Da' perpendicular to vector O'X' vbut, in this case, instead of having this plane Da, Da passing through the axis 0', it is located at a distance therefrom, whereby the planes passing respectively .through axis O and the two axes I, I' both make an angle equal to 0 with the plane passing through axis O' perpendicularly to vector OX' (Fig. 7) which angleA can, culation.4

By way of example, it may be noted that, in

order to obtain this result, it is necessary, in the case of a crankshaft having a single bend for a .'system including a master connecting rod and a tain reactions acting on the supports of the en-v gine but these reactions are not disturbing from` a practical point ofview.

The device which has just been described has the advantage that it is possible to utilise, for

- constituting the mass of pendulum I8', the'usual counterweight which must be provided in connection with the crank pin. As a matter of fact, it suffices to suspend this counterweight, for instance through a bilar suspension, to one of the crank arms 9 of the crankshaft.

Asfor pendulums p and p', they maybe merely pivoted in fork-shaped parts provided on the sides l of the same crank arm or of another crank arm. It should be noted that, if the plane DD passing through their axis of articulation also passes through axis O; the presenceof pendulums p, p' does not necessitate any modification of the mass of the usualcounterweight, therefore of the massA Aof pendulum I8.

when the crankshaft is to include, m addition to the pendular system which has just been described, a device for damping torsional vibrations constituted, for instancaby a second pendular- (Fig. 8) and c is the secondary rod, to comply approximately with the following condition: Y y

1 a=R sin 0 in which: l

a is the distance of axes I and I" from axis O; R is the eccentricity of the crank pin; and 0 is the angle above defined, this angle being preferably equal to In the case of a symmetrical crankshaft'with two bends provided with pendular systemsmerely on its extreme cranky arms, the relation between a and ri` (preferably equal to 90) must be;

=$R sin 0 I in which:

b is the distance between the middle point of a crank pin and'l the center of the crankshaft distance between eachof the compensating pendulums are middle of the corresponding planes in which the moving and the crank pin.

0f course, instead of two pendulums the axes of which are disposed along planes making an angle in every case, be determined by cal= upwardly with the plane normal to vector O'X' and passing through O', I might useseveral sets of such pendulums, for instance two sets for which the respective angles -'would be turned upwardly for one set and downwardly for the other.

In other words, instead of two pendulums at 45 in the upward direction with reference to O'X' (Fig. 7) I might utilize four at right angles to one another and each at 45 with respect to O'X'.

One might also have recourse to any other suitable arrangement, for instance utilize, either 6 -pendulums at 60 to one another (four of them being at 30 to O'X'), or 8 pendulums at 45 to one another.

In all cases, if the crankshaft has a single bend (radial engine with a single row), the pendular systems are placed either on only one crank arm (that located farther from the fixation of the engine to its frame) or on two crank arms, which is the solution which, theoretically, is the best.

If the crankshafthas two bends (double row engines) although it is possible to provide two pendular systems identical to each other and located on either side of each crank pin, it will be simpler to provide only two pendular systems by providing them on the end crank arms of the crankshaft (Fig. 8)

It will be readily understood that, in this case, the displacements of the pendulums which are opposed to the' two pulsatory torques at 180 to each other produce a periodical twisting of the shaft.

But it happens that the pendulums which oppose the two pulsatory forces at 180 to each other can oppose this periodic twisting.

It suffices for this purpose to have them dephased by an angle p t of a nature analogous to the angle a above referred to) which angle is automatically produced in view of the fact that the pendulums are wholly free to oscillate in response to the vibratory displacements of their fluid masses, for instance mercry masses, con-- tained in` vessels of suitable shape. I

For instance, according to the embodiment illustrated by Fig. 9, each of the crank arms 9 of crankshaft v carries two pieces on the inside of each of which there is provided a chamber at least a portion of which corresponds to a volume of revolution about one of the axes I, I' above-referred to in the description of Fig. '1.

Thus, if the various characteristics and dimensions of said portion are suitably determined and if a suitable mass of mercury is placed therein, it will be understood that, under the effect of the centrifugal force and of the perturbing vibrations, the displacements of said mass of mercury can produce, on the crankshaft, reactions identical to those produced, under the same circumstances, by the pendulums pi, p' of Fig. '1.

Preferably, the chambers intended to receive themass of mercury are given a closed outline so that the mercury does not undergo the action of any return force due to' a pressure of the air or gas contained in said chambers.

Likewise, in the whole portion in which the mercury is to move during the pendular movements which take place in the course of the operation, it will be advantageous to provide partitions of revolution about axes l, I', these partitions being intended to guide the mass of mercury along suitable curves and to avoid the disturbances which might otherwise be produced under certain conditions.

These partitions will be advantageously provided with holes which however enable the mercury to be regularly distributed on either side thereof.

They might of course be replaced by a nest of tubes the mean lines of which would be curved in the form of circular arcs having their center on axes l and I'.

Thus, I obtain in any case a radial engine in vwhich the perturbing effects en the crankshaft are for a considerable part compensated, therefore an engine the frame and accessories of which are practically protected against any injurious vibration as might act on the fixation parts of said engine or on the machine, such for instance as an to all Working conditions of the engine, due to the fact that the natural period of the pendular systems is a function of the centrifugal acceleration. and therefore of the speed of the engine, which is tantamount to saying that, if these systems aro arranged in such manner as to make, for instance, a complete oscillation per revolution under given conditions, they will make an oscillation per revolution under all other conditions.

It will be readily understood that the invention above described may receive many other applications. For instance it might be employed for damping the perturbing effects to which is subjected a part turning at a given speed by u pendular system carriedvby a shaft turning at a different speed.

Of course, in a general manner the invention is not in any way limited to the above described embodiments.

What I claim is:

1. In connection with an assembly including a rotary structure, said assembly being submitted to periodical impulses corresponding to a pulsatory force of order 1L directed along a radius of said rotary structure, a balancing device which comprises, in combination, two pendular systems eccentrically p ivoted to said rotary structure so as to rotate therewith at the mean speed ihm-enf and so as to be able to oscillate vabout axes parallel to the axis of said structure and situated on either side -of th; radial plane containing said radius, said penular systems including each a pendular mass and pendular connecting means between said mass and said rotary structure, said means being the sole force transmitting instrumentality betweemsaid mass and'said structure.

and the natural frequency of said pendular sys- 2,313,206 .tems when the angular velocity of the rotary structure is Q being substantially equal to the product of n by Si.

2. In connection with an. assembly comprising `a rotary structure, said assembly being submitted to periodical impulses corresponding to a pulsatory force of order n directed along a radius of.

said rotary structure, a balancing device which comprises, in combination, two pendular systems eccentrically pivoted to said rotary structure so as to rotate therewith at the mean speed thereof and so as to be able to oscillate about axes parallel to the axis of said structure and symmetrically situated relatively to a radial plane containing said radius, said pendular systems including each a pendular mass and pendular connecting means between said mass and said rotary structure, said means beingv the sole force transmitting instrumentality between said mass and said structure, and the natural frequency of said pendular system4 when the angular velocity of the rotary structure is il being substantially equal to the product of n by Sl.

3; In connection with an assembly comprising a rotary structure, said assembly being submitted .to periodical impulses corresponding to a pulsatory force of order n directed along a radius of said rotary structure, a balancing device which comprises, in combination, two pendular systems' eccentrically pivoted to said rotary structure so as to rotate therewith at the mean speed thereof and so as to be able to oscillate about axes parallel to the axis of said structure and situated, on

, either side of the radial plane containing said -radiusj in a plane normal to said radius and passing through the axis of rotation of said structure, said pendular systems including each a pendular mass and pendular connecting means between said mass and said structure, said means being the sole force transmitting instrumentality between said mass and said structure and the natural frequency of said pendular systems when the angular velocity of the rotary structure is Q being substantially equal to the product of n by Q.

4. InI connection with an-assembly comprising a rotary structure, said assembly being submittedV the crankpin, said pendular systems including each a pendular mass and pendular connecting means between said mass and said rotary structure, said means being the sole force transmitting instrumentality between said mass and said structure, and the natural frequency of said pendular systems corresponding substantially to one complete oscillation per revolution of the crankshaft.

' 6; In connection with an engine comprising radially disposed cylinders and pistons therein, acrankshaft having a crank pin, a master connecting rod associated with said crankpin and at least one auxiliary rod, a balancing device which comprises, in combination, two pendular systems eccentrically pivoted to said crankshaft so as to rotate therewith at the mean speed thereof` and so as to be able to oscillate about axes parallel to the axis of said crankshaft, and situated, on either side of the radial plane containing the axis of the crank pin, in a plane normal to said radial 4plane and having a distance from the rotating axis of said crankshaft,

and the natural frequency of said pendular syswhich comprises, in combination, three pendular systems eccentrically pivoted to saidvcrankshaft so as to rotate therewith at the mean speed thereof and so as to be able to oscillate about three axes parallel to the axis of said .crankshaft, the axes of two of said pendular systems bein'g'symmetrically situated on either side of to periodical impulses corresponding to a pulsatory force of order 11. directed along a radius of said rotary structure and to a pulsatory torque of the same order but shifted in phase with respect to said pulsatory force, said torque being located in a plane perpendicular to the axis of said rotary structure, a balancing Ydevice which comprises, in combination, two pendular systems eccentrically pivoted to said rotary structure so as to rotate therewith at the mean speed thereof,

and so as to be able to oscillate about., axes parallel to the axis of said structure and situated on either side of the radial plane containing saidA radius, in a plane normal` to said radius and having a distance from the axis of rotation of.

said structure, and the natural frequency of said 'pendular systems when the angular velocity of the rotary structure is f2 being substantially equal to the product of n by n.

5. In connection with an engine comprising a crankshaft having a crankpin, a master connecting rod associated with said crankshaft, and at least one auxiliary rod, a balancing device which comprises, in. combination, two pendular systems eccentrically pivoted to said crankshaft so as to rotate therewith at the mean speed thereof and so as to be able to oscillate about axes parallel to the axis of said crankshaft and situated on either side of the radial plane containing the axis of the radialv plane containing the axis of the crank pin, said pendular systems including each a pendular mass and pendular connecting means between said mass and said crankshaft, said means being the sole force transmitting instrumentality between said mass and said structure, and the natural frequency of said pendular systems corresponding substantially to onecomplete oscillation per revolution of the crankshaft.

8. A device according to claim4 in which, for a phase difference of between the pulsatory force and the pulsatory torque, each of the planes passing respectively through the`oscillation axis of each of said pendular systems on the one,

hand, and the Arotation axis ofithe rotary structure on the other hand, makes with a plane per-- pendicular. to the' vector of the rotary force and passing throughI the rotation axis of the rotary structure an angle of 45. 1

9. In connection with an engine comprising radially disposed cylinders and `pistons therein,.

type, being located on the other side of the axis of the crankshaft from said crank pina'nd'form'- ing at least a portion of the counterweight, said pendular systems including each a pendular mass and pendular connecting means between said mass and said crankshaft, said means being the 'sole force transmitting instrumentality between said mass and said structure, and the natural frequency of said pendular system corresponding substantially to one complete oscillation per revolution of the crankshaft.

10. In connection with an engine comprising radially disposed cylinders and pistons therein, a crankshaft having two crank webs, a crank pin, a master connecting rod associated with said crank pin and at least one auxiliary rod, two balancing devices according to claim 7, one of said devices being of order 1 and associated with the front crank web, the other of said devices being of higher order and mounted on the rear crank web so as to damp the torsional oscillations of the crankshaft.

11. In connection with an engine comprising a crankshaft having a crank pin, a master connecting rod associated with said crankshaft,

and at least one auxiliary rod, a balancing device which comprises, in combination, two pendular systems eccentri-cally pivoted to said crankshaft so as to rotate therewith at the mean speed thereof and so as to be able to oscillate about axes parallel to the axis of the crankshaft and located on either side of the radial plane containing theaxis of the crank pin, the planes passing respectively through the axes of said two pendular systems and through the axis of the crankshaft being inclined at 45 to a plane perpendicular to a. rotating pulsatory radial force