US2212272A - Balancing system for engines and machines having radially arranged cylinders - Google Patents

Description

ug- 20, 940 v R. MEDERER 2,212,272

BALANCING SYSTEM FOR ENGINES AND MACHINES HAVING RADIALLY ARRANGED ,CYLINDERS 4 Sheets-Sheet 1 Filed Aug. 4, 1938 |NVENTOR OBERT MEDERER BY ATTORNEY Aug. 20, 1940. R. MEDERER BALANCING 'SYS'I 'EM' FOB ENGINES AND MACHINES HAVING RADIALLY ARRANGED CYLINDERS 4 Sheets-Sheet 2 Filed Aug. 4, 1939 INVENTOR ROBERT MEDERER BY km mam 1Z4 ATTORNEY 0, 1940. v R. MEDERER 2,212,272 BALANCING SYSTEM FOR ENGINES AND MACHINES HAVING RADIALLY ARRANGED CYLINDERS Filed Aug. 4, 1938 4 ShQats-Sheot 3 INVENTOR ROBERT MEUERER BY kmsm ATTORNEY A z- 1940- R. MEDERER BALANCING SYSTEM FOR ENGINES AND MACHINES HAVING RADIALLY ARRANGED CYLINDERS Filed Aug. 4, 1938 4 Shoots-Sheet 4 INVENTOR ROBERT MEDERER BY ATTORNEY Patented Aug. 20, 1940 PATENT OFFICE- BALANCING SYSTEM FOR memes AND MACHINES navmc RADIALLY ARRANGED CYLINDERS Robert Mederer, Berlin, Germany Application August 4, 1938, Serial No. 222,949

'13 Claims.

The present invention relates to a system for balancing forces in the moving parts of radial engines and other machines with radially arranged cylinders, and it contemplates more par-. ticularly an improvement of that type of such engines and machines in which the connecting rods of all cylinders are operatively connected with the aid of pivot joints or articulations to an attaching member rotatable relatively to a crank pin of the machine.

An object of the invention is to provide for equal effects of the pressure in all cylinders and of the forces of the masses upon the cylinders and the crank shaft, and to obtain such result with the aid of a small number of additional parts. A further object of the invention is to provide a system with the aid of which, in consideration of the angular position of the cylinders relatively to each other, a uniform torque of the crank shaft and a practically complete equilibrium of the masses maybe obtained.' The invention has also for an object to prevent or at least minimize vibrations of the machine caused by a lack of uniformity for instance of the pressure of the pistons against the walls of the cylinders, and by an incomplete balance of the masses.

Another object of the invention is to increase by preventing or at least minimizing harmful vibrations, the life of a machine, which for instance in the case of an airplane engine of the radial type generally is in the neighborhood of only 500 to 600 hours, and to make such engine applicable for land vehicles.

The invention consists in a system according to which an attaching member rotatable on the crank pin and serving as a connecting means for the rods will be turned, during the rotation of the crank shaft, relatively to the crank pin in a direction opposite to that of the crank rotation and at such a rate that, for each of the connecting rods, the line connecting the center of the crank pin with'the point at which such rod is connected with said attaching member will during the revolution of the crank shaft maintain a constant direction, so that all the successive positions of said line will be parallel to each other., In other words, each of said points of connection travels on an individual circle.

The invention further consists in means to cause said attaching member to perform a translation in the plane of rotation of the crank pin, that is to say, to travel bodily about the crank shaft axis without rotation about its own axis which coincides with that of the crank pin.

The invention further consists in eccentric elements in connection with the attaching member and with the machine casing respectively and a control member connected to both said elements, whereby the attaching member will be turned 5 relatively to the crank pin in the manner set forth hereinbefore.

Further objects and details of the invention will be apparent from the description hereinafter of embodiments illustrated in the accompanying l0 drawings by way of example. In the drawings:

Fig. 1 is a cross-section of a three cylinder engine along line II of Fig. 2; I

Fig. 2 is a diagrammatic elevation of the system, partly in section along line IIlI of Fig. 1, 15 the parts being shown in four different positions;

Fig. 3 is a diagram of a modified system with eccentricities inclined in relation to the cylinder axes;

Fig. 4 is a sectional view of a modified system '20 according to the invention;

Fig. 5 shows another modification in a crosssection along line V-V of Fig. 6;

Figs. 6 and 7 are sectional views along line VIVI of Fig. 5 and showing parts of the modification of Fig. 5 in two different positions of the crank pin respectively;

Fig. 8 is a section along line VIII-VIII in Fig. 9 of another embodiment with auxiliary eccentric;

Figs. 9 and 10 are sectional views along line IX-iX of Fig. 8, showing the crank pin of a three cylinder engine in two different positions respectively;

Fig. 11 is a partial elevation of a modification of the embodiment of Fig. 8.

Referring now to Figs, 1 and 2, A indicates a crank shaft which may be hollow for reasons to be explained hereinafter. The crank of this shaft is formed by cheeks B and a crank pin C. D are connecting rods of the pistons E which reciprocate in the cylinders (not shown) of the machine. In the illustrated example the pistons are shown as belonging to a machine having three cylinders arranged at an angle of 120 with respect to each other. It is tobe understood, that the invention as described hereinafter is correspondingly applicable for machines having I any number of cylinders arranged radially at any angle with respect to each other. member or sleeve l of suitable design is rotatably mounted on the crank pin C, and the connecting rods D are pivotally connected to the attaching member by suitable means such as pins F. Pins F are equally spaced from the crank An attaching 5o pin axis 02 02 which is identical with the axis of the attaching member I, and the lines connecting the centers of the pin F with the center of the crank pin enclose angles of 120 with each other respectively. An eccentric 2 having its axis at 04 04 is rigidly connected to the attaching member I and an eccentric strap 3 is in engagement with the eccentric 2. A journal 4 is provided in fixed relation to the casing J of the machine and having its axis in offset or eccentric relation to the axis 01-01 of the crank shaft A. The eccentric strap 3 is pivoted on said journal 4 so as to act as a control member for determining with the aid of eccentric 2 the position of the attaching member I relatively to the crank pin C during the rotation of the crank shaft. In the illustrated example, journal 4 is integral with a journal body 5 which is shaped like a plunger and so arranged within the hollow crank shaft A that the latter can rotate while the body 5 remains stationary. Body 5 is non-rotatably secured for instance by a screw to a lid 6 rigidly connected to casing J by means not shown, and journal 4 projects from body 5 into the interior of the casing. The crank cheeks B and the control member 3 may be provided with extensions G1 and G2 respectively so designed as to form suitable counterpoises.

Journal 4 constitutes in relation to member 3 a crank pin stationary during the rotation of the crank shaft A,- and its eccentricity erwith respect to the crank shaft axis O1O1 is equal to the eccentricity er of the eccentric 2 rotatable in relation to the crank pin C. r

The axes O2O2 and O4-04 are in the same axial plane of the crank case with the axes O1-O1 and O3-O3 when the crank is for instance in the position a shown in Fig. 2.

Now it will be apparent that, upon rotation of the crank shaft A, member 3 will be rotated about journal 4. Owing to the eccentricity e1, 'said member exerts a control force upon eccentric 2 which it rotates, thereby causing a relative rotation of link member I and crank pin C. Furthermore, it will be noted that upon such rotation of the system, a straight line connecting the crank shaft axis 01 with the crank pin axis 02 (in a transverse plane, as in Fig. 2) always remains equal and parallel to a straight line connecting the axis 03 of the stationary journal 4 with the axis 04 of the relatively rotatable eccentric 2. Consequently, during the rotation of the shaft A there is formed a moving and form changing parallelogram O1 O2 O3 O4 in which the side 02 04, i. e. the eccentricity e: of the relatively rotatable eccentric, is always parallel to the side 01 03, i. e. the eccentricity e1 of the journal 4 constituting a stationary crank (see the four positions a-d of the parts in .Fig. .2). -Thus, the

eccentricity er of the relatively rotatable eccentric 2 (that is the line 02 O4 in Fig. 2) always remains parallel to itself during the rotation of the crank. Owing to the fact, however, that eccentric 2 is rigidly connected to attaching member I, the lines connecting the points of pivotal connection F of rods D to the attaching member I with the center 02 of the crank pin C remain parallel to themselves respectively. Hence, the attaching member I performs a translation, and the points of pivotal connection F of rods D travel on circular paths which are respectively symmetric in relation to the pertaining cylinder axes.

During the rotation of the crank shaft in the direction of the arrow 1', the eccentric 2 rotates relatively to the crank pin C in the direction of the arrow ii, that is tosay, in a direction opposite to that of the rotation of the crank. In the position a of Fig. 2 inwhich position the crank pin C and the eccentric 2 are subject to the full explosion pressure of the cylinder, a great friction opposes the relative rotation of the eccentric 2 in the direction of the arrow ii. Due to this fact, disturbances may occur in overcoming this dead center position.

In order to avoid such disturbances, the eccentricity er of journal 4 (that is to say, the position of the stationary line 01 03) may be so'arranged as to enclose angles with the axes H1 H2 H: of the radial cylinders. This is shown in Fig. 3. In the illustrated arrangement, the lines 02 O4 (eccentricity e2 of eccentric 2), being parallel to the line 01 a (eccentricity 61), can never coincide with the direction of any one of the connecting rods so as to cause a dead center position. There will alwaysexist a torque which assists the relative rotation of the eccentric 2 in the direction of the arrow i2.

In order to decrease the friction and the dead angle at the eccentric 2, the latter may be designed as an interior eccentric as shown in the example of Fig. 4. In this modification an interior or tubular eccentric 2| is rigidly secured to'the attaching member I. An eccentric strap 3| is rotatable within eccentric 2|, and its rod 3| is pivoted at the stationary journal 4 which is eccentric with respect to the crank shaft center.

In Figs. to 7, an embodiment of the invention is shown in which attaching member I is provided with an extension I coaxial with the crank pin C. Two eccentrics 22 and 23 are mounted on said extension and secured to the attaching member against relative rotation by means of a screw 1. The eccentrics 22 and 23 have their centers out of alignment, so that lines drawn from such centers to the center oi the crank pin C will enclose an angle with each other as indicated by the V-shaped dotted lines in Figs. 6

and 7. Within the hollow crank shaft A, an axle Si is provided about which the shaft can rotate. Axle 5| is secured with one of its ends to the casing J by suitable means such as screws, and is provided at its other end with two journals 42 and 43 connected to each other. The journals 42 and 43 are parallel to each other and eccentric in relation to the crank shaft axis. Eccentric 22 is connected to journal 42 by means of a control member 32 constituting the associated eccentric strap, and eccentric 23 is connected to journal 43 by means of control member 33 which constitutes the eccentric strap associated with eccentric 23. The eccentricities of the associated eccentrics and journals are equal and throughout the rotation of the crank shaft, the line connecting the ,center 04' of the eccentric 22 with the center 02 of the crank pin C will remain parallel to the line connecting the center 03' of the journal 42 with the center 01 of the shaft A, while at the same time the line connecting the center 04" of the eccentric 23 with the center Oz of said crank pin C will remain parallel to the line connecting the center 03" of the journal 43 with the center 01 of shaft A. In this manner, two guide parallelograms are formed which insure a rotation of the attaching member I relatively to the crank pin C in the direction it opposite to the direction z of the crank rotation, so as to prevent the occurrence of an undesirable dead angle. This twin parallelogram arrangement neutralizes the eiIectS of compression and tension strains. This is of particular importance for the bearing of the attaching member in very powerful engines of several thousand H. P. Moreover, the arrangement is helpful to overcome any dead center of the eccentrics in a very satisfying manner. A coupling triangle formed by the centers-of the eccentrics 22,23 and of the crank pin is guided parallelly by a similar coupling triangle formed by the centers of the stationary journals 42, 43 and the crank shaft, whereby the influence of the dead angles of the eccentrics 22 and 23 is considerably reduced.

In Figs. 8 to 11, devices are illustrated which serve to attain the same purpose. Figs. 8 to show, in addition to eccentric 2 and to the stationary journal or crank pin 4, another eccentric 8 which is rotatably mounted in the counter-- poise G: of the control or strap member 3, and pivoted on a journal 9 secured to the counterpoise G1 of the crank cheek B. The eccentric'8 has an eccentricity equal to those of the eccentric 2 and the stationary journal 4, and the line connecting the center of the eccentric 8 with the center of the journal 9, as well as the line connecting the center 04 of the eccentric 2 with the center 02 of the crank pin C, remain parallel to the line connecting the center 03 of the stationary journal with the center 01 of the shaft A, throughout the operation of the machine. rotation of the crank shaft, the eccentric 8 rotates about journal 9 in the direction of the arrow ii, that is to say, opposite to the direction 11 of the crank rotation. In so doing, the eccentric 8 assists in overcoming the dead center of the eccentric 2 rotatable relatively to the crank pin' faces or tracks i2 of the counterpoise G1 of the crank cheek B. The lines connecting the roller centers with the centers of the circular surfaces 12 are equal and parallel to lines drawn cor-- respondingly with respect to the relatively rotatable eccentric 2 and the stationary journal 4. In Fig. 11, two rollers are shown in symmetric arrangement as to the center plane of the counterpoise G2. 1 1

Although I have shown certain specific embodiments, I desire it to be understood that my invention is not limited to the structures shown and that many modifications in the shape and arrangement of parts will be apparent to those skilled in the art without departing from the scope and spirit of my invention. For instance crank and similar devices are to be considered as equivalents of the eccentrics shown and may be used in their place. The invention may be applied to motors as well as to driven machines with radial cylinders, such as pumps, compressors,

etc., and may also be fitted into, existing machines, frequently without alteration of either i the crank case or the crank shaft.

What I claim is:

1. A balancing system for machines having a casing, a crank shaft having hollow axial portions journaled in said casing, cheeks extending outwardly from said axial portions. a crank pin at the outer portions of said cheeks, an attaching member mounted to turn on said crank pin, a plurality of pistons. arranged to reciprocate radially with respect to said shaft, a connecting Upon I rod extending from each of said pistons and movably secured to said attaching member, at least one eccentric member rigidly connected with said attaching member and having its axis eccentric to that of said crank pin, at least one additional eccentric member the axis of which is eccentric to that of said crank shaft, said additional eccentric member extending into a hollow portion of said shaft and engaging such portion peripherially, and being rigidly secured to said casing, and a control member movably connecting the firstmentioned eccentric member with said additional eccentric member, the said two eccentric members having equal eccentricities, and a line which connects the center of the first-mentioned eccentrio with the center of the crank pin being parallel, in any position of the crank pin, to a line from each of said pistons and movably secured to said attaching member, an eccentric member rigidly connected with said attaching member and having its axis eccentric to that of said crank pin, a stationary eccentric member the axis of which is eccentric to that of said shaft, and a control member movably connecting the firstmentioned eccentric member with said stationary eccentric member, said eccentric members having equal eccentricities, and a line which connects the center of the first-mentioned eccentric member with that of the crank pin being parallel, in any position of the crank pin, to a line connecting the center of the stationary eccentric memher with that of the shaft.

3. A system as claimed in claim 2, in which the shaft has a hollow portion into which extends part of the stationary eccentric member, on which part said hollow shaft portion is journaled.

4. A system as claimed in claim 2, in which the control member consists of an eccentric strap in rotary engagement with the eccentric on the attaching member and fulcrumed on the stationary eccentric.

5. A system as claimed in claim 2, in which the axis of the shaft and that of the stationary hollow shaft portion into which said member extends.

9. A system as claimed in claim 2, in which there'is provided a second eccentric member rigidly connected with the attaching member to move therewith, the center of such second eccentric memberbeing out of line angularly with the center of the other eccentric member rigidly connected with the attaching member so that lines drawn from said centers to the center of the crank pin will form an angle with each other, a

second stationary eccentric member, the eccentricity of which isequal to that of the abovementioned second movable eccentric member and the center of which is out of line with the center of the other stationary eccentric member to the same extent that the center of said second movable eccentric member is out of line with the center of the other movable eccentric member, -so that lines drawn from the center of the shaft to the centers of the two stationary eccentric members will form the same angle with each other as the lines drawn from the centers of the two movable eccentric members to the center of the crank pin, and will be respectivelyparallel .to the last-mentioned lines, and a second control member movably connecting said second movable eccentric member with said second stationary eccentric member.

10. A balancing system for machines having a shaft with outwardly extending cheeks and a crank pin connecting said cheeks, an attaching member mounted to turn on said crank pin, a plurality of pistons arranged to reciprocate radially with respect to said shaft, a connecting rod extending from each of said pistons and movably secured to said attaching member, an eccentric member rigidly connected with said attach- 'ing member to move therewith, and having its axis eccentric to that of said crank pin, a stationary eccentric member the axis of which is eccentric to that of said shaft, a control member movably connecting said eccentric members, said eccentric members having equal eccentricities,

and a line which connects the center of the said movable eccentric member with that of the crank pin being parallel, in any position of the crank pin, to a line connecting the center of the stationary eccentric member with that of the shaft, and two co-operating connecting means in eccentric relationto each other, one of said connecting means being on said control member, and the other on one of the crank cheeks of the shaft, the eccentricity of such connecting means relatively to each other being equal to that of said stationary eccentric member, and a line which connects the centers of the two co-operating connecting means being parallel, in any position of the crank pin, to a line connecting the center of the stationary eccentric member with that of the shaft.

11. A balancing system as claimed in claim 10, in which one of the connecting means consists of a journal and other of an eccentric engaging said journal.

12. A balancing system as claimed in claim 10, in which pne of the co-operating connecting means comprises at least two rollers, and the other circular tracks for said rollers, one of said means being on the control member, and the other on one of the crank cheeks of the shaft.

13. A balancing system as claimed in claim 2, in which the eccentric rigidly connected with the attaching member is tubular and in which the mating end of the control member engages the inner surface of said eccentric.

ROBERT MEDERER.

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