EP2426336B1 - Piston with two pivot bearings and double crankshaft piston engine - Google Patents

Description

The present invention relates to a double crankshaft piston engine according to the preamble of patent claim 1.

BACKGROUND OF THE INVENTION

A problem with double crankshaft reciprocating engines is to synchronize the two rotating crankshafts with each other. In this case, each of the crankshafts, for example, provided with a synchronization gear, wherein the synchronization gears are engaged with each other. By thermal influences during operation of the double crankshaft piston engine or by wear on the tooth flanks of the synchronization gears, a backlash between the intermeshing teeth of the synchronization gears can occur, which in turn causes a slight asymmetry of the circulation of the crankshafts, whereby an undesirable tilting of the piston in the cylinder can be caused. In such an asymmetry of the circulation of the crankshafts, the crankshafts and with them the entire crank drive while synchronized in time, but rushes forward one of the crankshafts with respect to the other crankshaft during circulation, so that the crankshaft-side connecting rod bearing axes not at the same time, but successively their top dead center to reach. This in turn means that the piston-side connecting rod bearing successively reach their top dead center, which leads to a tilting movement in the piston. Of course, this flow of the one crankshaft relative to the other crankshaft is valid for the entire revolution of the synchronized crankshafts, which therefore revolve at the same speed, which is referred to in this application as "asymmetry of the rotation of the crankshafts". Due to this asymmetry, as has already been explained, a tilting moment is exerted on the piston towards the top dead center of the piston and at bottom dead center of the piston a corresponding overturning moment to the other side. The piston therefore simultaneously describes, during its upward and downward movement, a tilting movement reversing in the respective dead center to one side and to the other side in the plane which intersects the crankshaft axes at right angles.

STATE OF THE ART

To solve this problem, is in the US 2010/0077984 A1 proposed to store the two crankshafts in a common bearing block and to select the material of the bearing block and the material of the crankshaft and the synchronization gears in terms of their thermal expansion coefficient so that the thermal expansion of the bearing block between the two axes of rotation of the crankshafts to avoid backlash between the tooth flanks is substantially identical to the thermal expansion of the synchronization gears. The design effort for this, however, is not insignificant.

From the DE 10 2006 060 660 A1 an adjustable bearing block for a double crankshaft piston engine is known in which the distance between the crankshaft axes is adjustable, so that in this way an undesirable bearing clearance and backlash can be eliminated. This solution is relatively expensive from the technical implementation ago.

From the DE 10 2006 036 827 A1 It is known to provide a piston with a spherical outer contour in a double crankshaft piston engine. This piston tolerates a slight tilting of the piston longitudinal axis with respect to the cylinder longitudinal axis occurring in the case of asymmetry of the circulation of the crankshafts, without jamming of the piston in the cylinder or increased friction occurring.

The US 5,732,673 A shows and describes a piston-cylinder machine with variable stroke. This machine is equipped with two parallel crankshafts that rotate in the same direction and are synchronized with each other via a gear transmission. Each piston is connected via a connecting rod with the two crankshafts, wherein the connecting rods are rotatably mounted on the crankshafts in a conventional manner. In the piston pivotally mounted in the piston center plane rocker arm is provided at the respective end of the connecting rod is pivotally mounted. The connecting rods run in such a way that they pass through the piston center plane in each case. The object of this design is to make the piston stroke variable in order to adjust the compression ratio variable. For this purpose, a targeted adjustment of the rotational position of the two crankshafts relative to each other, which in conjunction with the same direction of rotation of the crankshaft causes the top dead center and the bottom dead center of the piston have a different distance from each other than in the case of non-angularly offset crankshafts.

The US 5,769,610 A and the US 5,674,053 A show and describe a high pressure compressor, which is equipped with a double crankshaft drive, wherein each piston is associated with a respective crankshaft connected in a conventional manner connecting rod and wherein the two connecting rods are mounted in the piston in a spherical bearing. The two crankshafts rotate in opposite directions and the connecting rods connected to the piston do not cross each other. In the area of their piston side bearing the two connecting rods are in mutual rolling contact with each other.

The DE 10 2004 016 203 A1 shows and describes a reciprocating internal combustion engine with a double crankshaft arrangement, which aims to move the bearing point between the two connecting rods and the piston in the direction of the two crankshafts and thereby move out of a hot and damaging area of the cylinder out , There are different variants of the Linkage of the connecting rod to a connected to the piston and led out of the cylinder rod shown, with some variants have a hinged to the rod at its end remote from the piston pivotally mounted condyle, on which a respective connecting rod is articulated.

The JP 10220547 A 1 shows a piston-cylinder arrangement in which a piston with a long piston rod, which is guided out of a cylinder housing via a thrust bearing, is connected via a joint head connected in an articulated manner to the end of the piston rod facing away from the piston, on which two connecting rods of a double crankshaft Crank drive are articulated. In another embodiment, the piston rod is mounted in the piston at a "joint" and possibly pivotable there. At the end remote from the piston of the piston rod, the two connecting rods are mounted laterally spaced from each other on a joint head.

The JP 61-149745 U shows a double crankshaft piston-cylinder assembly in which the crankshaft rotate in opposite directions synchronously and are in synchronization via gears with each other and in which the connecting rods are articulated on a common axis on the cylinder.

The BE 423 799 A shows and describes a piston with two pivot bearings for pivotally mounting a respective connecting rod on the piston about a respective Pleuelschwenkachse, wherein the two Pleuelschwenkachsen parallel to each other and laterally spaced from each other and wherein the two pivot bearings are provided on a bearing element which is pivotable about a Lagerschwenkachse on the piston is mounted, which runs parallel to the Pleuelschwenkachsen. With this bearing construction is to be achieved that the occurrence of wear on organs of the crank mechanism or other defectiveness of the crank mechanism, the bearing element oscillates easily in the piston.

PRESENTATION OF THE INVENTION

Object of the present invention is to ensure in a generic double crankshaft piston engine that the desired in the occurrence of wear in the crank drive oscillatory movement of the bearing element in the piston can be done reliably, even if the double crankshaft piston engine has been in operation for a long time.

This object is achieved by a double crankshaft piston engine having the features of patent claim 1.

This double crankshaft piston engine, which has at least one piston-cylinder unit, is provided with a cylinder in which a reciprocating piston is reciprocally arranged, with a first crankshaft, with a second crankshaft, wherein the first crankshaft and the second crankshaft run parallel to each other and rotate in opposite directions synchronously, the axes of rotation of the two crankshaft parallel to a common cylinder center plane and are laterally offset with respect to this, the reciprocating piston, a first and a second connecting rod are assigned such that the first connecting rod with its first End in a first pivot bearing about a first Pleuelschwenkachse pivotally mounted on the reciprocating piston and with its second end to a crank pin of the first crankshaft and that the second connecting rod with its first end in a second pivot bearing about a second Pleuelschwenkachse pivotally mounted on the reciprocating piston and with its second End at one Crank pin of the second crankshaft is rotatably mounted, wherein the pivot bearings are provided on a bearing element which is pivotally mounted on the piston about a bearing pivot axis which is parallel to the Pleuelschwenkachsen. This double crankshaft piston engine is inventively characterized in that the arrangement of the two counter-rotating synchronously rotating crankshaft is designed so that the crank pin already in new condition, when no wear has occurred, slightly asymmetric in opposite directions ..

ADVANTAGES

This according to the invention provided over the prior art targeted asymmetry of the crank mechanism already in the new state of the double crankshaft piston engine causes the oscillation movement of the bearing element in the piston takes place when first commissioning the double crankshaft piston engine. The bearing element thus performs constantly, so even in new condition, a swinging pivotal movement in the bore of the piston. Therefore, a high bearing pressure occurring at the point of reversal of motion due to the revolving movement of the piston does not occur locally as a point load, thereby preventing a punctiform deformation of the bearing surfaces caused by bearing pressure.

Now occurs in addition to wear in the crank mechanism, so the bearing element in a nonuniformity of the connecting rod, so in an asymmetry of the circulation of the crankshaft, continue to rotate relative to the piston and thus compensates - as in the prior art - the wear-related asymmetry of the circulation of the two Crankshafts, without the piston is thereby tilted with its piston longitudinal axis with respect to the cylinder longitudinal axis. The symmetrical design ensures symmetrical force ratios and favorable kinematic conditions.

It is advantageous if the asymmetry of the circulation of the crank pin is a maximum of 5 °, preferably between 1 ° and 3 °, more preferably 2 °.

It is also advantageous if the asymmetry of the rotation of the crank pin by an angular displacement of 1 to 6 teeth between mutually engaged Synchronisationszahnrädern the first and the second crankshaft is effected.

Preferably, the bearing pivot axis, measured in a swivel plane which intersects the bearing pivot axis at right angles, is equally spaced from the connecting rod pivot axes. This symmetrical structure ensures symmetrical power relations.

The bearing pivot axis is preferably located on the middle of a line connecting the Pleuelschwenkachsen in the pivoting plane with each other. Also by this embodiment, advantageous kinematic conditions are created.

A preferred development of the double crankshaft piston engine is characterized in that the bearing element has a circular contour or two, preferably symmetrical to each other, circular segment-shaped contours whose circle center is on the bearing pivot axis that the piston with an adapted circular contour or with adapted circular segment-shaped contours is provided, the center of the circle is also on the bearing pivot axis, and that the circular or circular segment-shaped contours of the bearing element and the circular or circular segment-shaped contours of the piston in mutual contact, but are arranged to be movable relative to each other about the common pivot bearing axis. This circular or circular segment-shaped design of the bearing element can be particularly easily integrated into the piston.

The bearing element can be formed as a disk or as a ring and the circular contour or the circular segment-shaped contours is or are formed on an outer peripheral edge of the bearing element. Alternatively, the bearing element may be formed as a ring and the circular contour or the circular segment-shaped contours may or may be formed on an inner peripheral edge of the bearing element.

The essence of the invention is therefore that the arrangement of the two oppositely synchronously running crankshafts is designed so that the crank pin rotate in opposite directions, but slightly asymmetric. This asymmetric rotation means that the crankpin of a crankshaft with respect to the crankpin of the other crankshaft slightly ahead, so for example, reaches its top dead center and its bottom dead center slightly earlier than the other crankpin. This specifically created asymmetry ensures that, ideally, in which there is no wear in the synchronization gears, nevertheless a slight relative rotation of the bearing member relative to the piston takes place to prevent the bearing of the bearing element is deformed in the piston by static permanent load.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine teilweise geschnittene Stirnansicht einer Doppelkurbelwellen-Kolbenmaschine mit einem erfindungsgemäßen Kolben;

Fig. 2

einen Vertikalschnitt entlang der Linie II-II in Fig. 1;

Fig. 3

eine teilweise geschnittene Stirnansicht einer zweiten Ausführungsform eines erfindungsgemäßen Kolbens;

Fig. 4

eine teilweise geschnittene Stirnansicht einer dritten Ausführungsform eines erfindungsgemäßen Kolbens und

Fig. 5

eine Doppelkurbelwellen-Kolbenmaschine gemäß der vorliegenden Erfindung bei geringfügiger Asynchronität des Kurbeltriebs.

The invention will now be described by way of example with reference to the drawings. In this shows:

Fig. 1

a partially sectioned end view of a double crankshaft piston engine with a piston according to the invention;

Fig. 2

a vertical section along the line II-II in Fig. 1 ;

Fig. 3

a partially sectioned end view of a second embodiment of a piston according to the invention;

Fig. 4

a partially sectioned end view of a third embodiment of a piston according to the invention and

Fig. 5

a double crankshaft piston engine according to the present invention with slight asynchrony of the crank mechanism.

PRESENTATION OF PREFERRED EMBODIMENTS

In Fig. 1 a double crankshaft piston engine according to the present invention is shown with a piston 1 according to the invention, in a provided with a cylinder head 20 cylinder 2 along the, ideally, the piston axis From the lower connecting rod 50, 60 each extending a connecting rod 52, 62 of the respective connecting rod 5, 6 up to the piston 1. At its upper, piston-side end of the respective connecting rod 5, 6 is provided with an upper connecting rod 54, 64, respectively on a piston-side crankpin 14, 16 about an associated upper Pleuelschwenkachse or Pleuelaugenachse Y5, Y6 is pivotally mounted in a Pleuelschwenkachsen perpendicularly intersecting pivot plane E1.

The upper, piston-side connecting rod trunnions 14, 16 thus form pivot bearings 55, 65 for the articulated mounting of a respective connecting rod 5, 6 on the piston 1.

The upper, piston-side connecting rod trunnions 14, 16 are provided in a bearing element 12 pivotably mounted in the piston body 10. The pivot axis Y7 of the bearing element 12 extends parallel to the pivot axes Y5 and Y6 of the upper pivot bearings 55, 65 of the connecting rods 5, 6.

The bearing pivot axis Y7 is located at the center of the connecting rod pivot axes Y5, Y6 in the pivot plane E1 interconnecting straight line G and is therefore equally spaced from the two Pleuelschwenkachsen Y5, Y6.

The structure of the bearing member 12 will be described below with reference to FIGS Fig. 1 and 2 explained.

The bearing element 12 has a circular cylindrical outer contour 13 whose center of the circle lies on the axis Y7. With this circular outer contour 13, the cylindrically shaped bearing element 12 is rotatably received in an adapted bore 15 in a lower region of the piston 1. The bore 15 is in a lower web portion 17 of the piston 1 facing the crank drive educated. This web portion 17 lies on the side facing away from the piston head 18 of the piston 1 side.

The bearing element 12 has two end wall sections 12 ', 12 "facing away from one another, which are spaced apart in the direction of the pivot axis Y6 of the bearing element 12 and form a gap in which the respective connecting rod 5, 6 engages with its piston-side end section 14, 16 extend between the two wall sections 12 ', 12 "of the bearing element 12.

In the region of the circumference of the bearing element 12, the wall sections 12 ', 12 "are interconnected via an upper web 120, a lower web 121 and lateral peripheral wall sections 122, 123. Along the circumference are between the lower web 121 and the respective peripheral wall sections 122, 123 Through openings 124, 125 for the respective connecting rod shaft 52, 62 of the connecting rod 5, 6. The extension of the passage openings 124, 125 in the circumferential direction of the bearing member 12 is dimensioned such that the connecting rods 5, 6 neither in their pivotal movement about the axes Y5, Y6 be obstructed by the lower central web 121, nor by the lateral peripheral wall sections 122, 123.

The piston 1 is conventionally provided with piston rings 10 ', 10 ", the construction and operation of which will not be further explained here, since it is generally known to the person skilled in the art. which can be in sliding friction with the bore of the cylinder 2 and the piston 1 can be supported in this way against a possible tilting movement transverse to the piston and cylinder axis X on the cylinder inner wall 21.

Fig. 3 shows a modified embodiment of the piston and the piston machine, in which the bearing element 212 is provided as an annular disc with a central, concentric to the axis Y7 bore 213. The lower land portion 217 of the piston 201 is provided with a cylindrical journal 215 extending with its axis coaxial with the axis Y7 and on the radially outer periphery 215 'of the inner circumference 212 "of the annular disk body 212' of the bearing member 212 is rotatably mounted.

The upper pivot bearings 255, 265 of the connecting rods 205, 206 are formed as in the first embodiment with provided on the bearing element 212 connecting rod journal 214, 216, which are located on both sides of the central bore 213 of the bearing element 212 with respect to the piston and cylinder axis X and with their respective Axis Y5, Y6 extend parallel to the axis Y7.

In Fig. 4 a further embodiment of the piston according to the invention and the piston machine according to the invention is shown, in which the bearing element 312 has the shape of two in the region of the piston and cylinder axis X abutting and interconnected circular segment sections 312A, 312B. The bearing element 312 therefore has a body 312 'of bone-like shape, on whose lateral outer sides circular cylindrical segment-like surface portions 312 ", 312''' are formed whose radius of curvature lies on the pivot axis Y7 of the bearing element 312.

The under web portion 317 of the piston 301 is similar to the embodiment of the Fig. 1 , provided with an aperture 315 which extends in the direction of the axis Y7. This breakthrough opening 315 has two lateral circular cylinder segment-like curved inner surfaces 315 ', 315 "whose radius of curvature lies on the axis Y7, such that the curvature of these lateral surfaces 315 ', 315 "corresponds to the curvature of the circular cylinder segment-like surface portions 312", 312 "' of the bearing element 312. The length of the curved inner surfaces 315 ', 315" in the direction of curvature is greater than the length of the curved surface portions 312 " , 312 '"of the bearing element 312 and also the vertical dimensions (in the direction of the axis X) of the aperture 315 are larger than the vertical dimensions of the bearing element 312, so that there is sufficient space above and below the bearing element 312 inserted into the aperture 315, Thus, the bearing element 312 in the breakdown recess 315 can perform a swinging pivotal movement about the axis Y7.

The upper pivot bearings 355, 365 of the connecting rods 305, 306 are formed as in the first embodiment with arranged on the bearing element 312 connecting rod trunnions 314, 316 which are located on both sides of the axis Y7 with respect to the piston and cylinder axis X and their axes Y5, Y6 parallel extend to the axis Y7.

The operation of the piston engine of the piston engine with the piston according to the invention will be described below with reference to Fig. 5 explained. The in Fig. 5 shown piston engine corresponds in its construction to the Fig. 1 , so that the same reference numerals as in the Fig. 1 be used.

In the presentation of the Fig. 5 It can be seen that the angle α1 between a straight line G1 connecting the two crankshaft axes Y1 and Y2 and a straight line G2 connecting the crankshaft axis Y1 and the lower connecting-rod bearing axis Y3 of the first connecting rod 5 is greater than the corresponding angle α2 between the straight line G1 and the one Crankshaft axis Y2 of the second crankshaft 4 with the bottom connecting rod Y4 of the second connecting rod 6 connecting straight line G3. As a result, an asymmetry between the left crank mechanism with the crankshaft 3 and the connecting rod 5 and the right crank mechanism with the crankshaft 4 and the connecting rod 6 is created. This asymmetry can arise, for example, due to wear on the tooth flanks of the meshing synchronization gears 30, 40.

Although the two crankshafts 3, 4 rotate at the same rotational speed in opposite directions R1, R2 and are thus synchronized in time, the asymmetry causes a lead of the crankshaft 4 and thus also the connecting rod 6 with respect to the crankshaft 3 with the engine 5. This lead leads to this in that during the upward movement of the crankshaft-side connecting rod journal 42, the bearing element 12 is pivoted about its axis of rotation Y7 in the direction of rotation of the leading crankshaft 4, ie counterclockwise in the example shown, as shown by the arrow R3. In a downward movement of the crankshaft side connecting rod journal 42 of the second, leading crankshaft 4, the direction of rotation of the bearing member 12 is reversed, so that the bearing element 12 is now pivoted clockwise according to the arrow R4. In this way, the bearing member 12 performs a swinging pivotal movement in the bore 15 of the piston 1 without the piston 1 tilted with respect to the longitudinal axis X.

Also in the examples of 3 and 4 performs the corresponding bearing element 212, 312 in the same way corresponding oscillating pivoting movements.

Are the two intermeshing synchronization gears 30, 40 aligned exactly zueinader and there is no wear in the intermeshing teeth of these synchronization gears 30, 40, so For example, in the simplest case of the present invention, the angles α1 and α2 are identical as in the embodiment of FIG Fig. 1 is shown. In this case occurs so long no pendulum movement of the bearing body 12 in the bore 15 of the piston 1 until a occurring between the teeth of the synchronization gears 30, 40 wear leads to the already described asymmetry of the circulation of the crankshafts 3, 4. However, the bearing member 12 does not move relative to the piston 1, so if no oscillating pivoting movement takes place, it may be due to bearing pressure to deformation of the bearing surfaces between the outer peripheral surface of the bearing element 12 and the inner peripheral surface of the bore 15, the relative pivoting of the bearing element 12th obstructed or even impossible with respect to the piston 1. In order to prevent such deformation of the bearing surfaces between the bearing element 12 and the piston 1, even when new condition of the piston engine, so if between the synchronization gears 30, 40 still no wear has occurred, a slight asymmetry in the sense of a Ungleicheit the angle α1 and α2 like this in Fig. 5 is shown provided. As a result, the bearing element 12 performs constantly, so even in new condition, a pendulum pivotal movement in the bore 15 of the piston 1, whereby a bearing pressure and the associated deformation is prevented. If wear then occurs in the region of the teeth of the meshing synchronization gears 30, 40, then the original oscillating pivotal movement of the bearing element 12 increases. The piston 1 is thus never subjected to a tilting movement induced by the crank drive.

The invention is not limited to the above embodiment, which is merely the general explanation of Core idea of the invention is used. Within the scope of protection, the device according to the invention may also assume other than the above-described embodiments. In this case, the device may in particular have features that represent a combination of the respective individual features of the claims.

Reference signs in the claims, the description and the drawings are only for the better understanding of the invention and are not intended to limit the scope.

LIST OF REFERENCE NUMBERS

1

piston

2

cylinder

3

crankshaft

4

crankshaft

5

pleuel

6

pleuel

10

piston body

10 '

piston ring

10 "

piston ring

11

Skirt section

11 '

Skirt section

12

bearing element

12 '

end wall section

12 "

end wall section

13

circular outer contour

14

piston-side connecting rod journal

15

drilling

16

piston-side connecting rod journal

17

lower bridge section

18

piston crown

20

cylinder head

21

Cylinder inner wall

22

compression chamber

30

synchronization gear

32

pivot

40

synchronization gear

42

pivot

50

lower connecting rod eye

52

connecting rod shaft

54

Upper connecting rod eye

55

pivot bearing

60

lower connecting rod eye

62

connecting rod shaft

64

Upper connecting rod eye

65

pivot bearing

120

upper jetty

121

lower jetty

122

lateral peripheral wall section

123

lateral peripheral wall section

124

Through opening

125

Through opening

201

piston

205

pleuel

206

pleuel

212

bearing element

212 '

annular disk body

212 '

inner circumference

213

concentric bore

214

piston-side connecting rod journal

215

cylindrical bearing journal

215 '

circular outer circumference

216

piston-side connecting rod journal

217

lower bridge section

255

Upper pivot bearing

265

Upper pivot bearing

305

pleuel

306

pleuel

312

bearing element

312 '

corpus

312 '

circular cylindrical surface section

312 ''

circular cylindrical surface section

312A

Circular segment section

312B

Circular segment section

314

connecting rod

315 '

lateral area

315 '

lateral area

316

connecting rod

355

Upper pivot bearing

365

Upper pivot bearing

E1

pivot plane

E2

Cylinder mid-plane

G

Just

X

Piston and cylinder axis

Y1

axis of rotation

Y2

axis of rotation

Y3

lower connecting rod axis

Y4

lower connecting rod axis

Y5

upper connecting rod axis

Y6

upper connecting rod axis

Y7

swivel axis

Claims (8)

1. A twin crankshaft piston engine with at least one piston cylinder unit, comprising:

   - a cylinder (2) in which a reciprocating piston (1; 201; 301) is disposed, so that it can move back and forth;

   - a first crankshaft (3);

   - a second crankshaft (4);

   - wherein the first crankshaft (3) and the second crankshaft (4) extend parallel to one another and rotate synchronously in opposite directions;

   - wherein the rotation axes (Y1, Y2) of the two crankshafts (3, 4) extend parallel to a common cylinder center plane (E2) and are laterally offset with respect to the cylinder center plane;

   - wherein a first and a second connecting rod (5, 6) is associated with the reciprocating piston (1; 201; 301) in such a manner

   t hat the first connecting rod (5) is pivotably supported with its first end at the reciprocating piston (1; 201; 301) in a first pivot bearing (55; 255; 355) about a first connecting rod pivot axis (Y5) and rotatably supported with its second end at a crank pin (32) of the first crankshaft (3) and

   t hat the second connecting rod (6) is pivotably supported with its first end at the reciprocating piston (1; 201; 301) in a second pivot bearing (65; 265; 365) about a second connecting rod pivot axis (Y6) and rotatably supported with its second end at a crank pin (42) of the second crankshaft (4),

   - wherein the pivot bearings (55, 65; 255, 265; 355, 365) are provided at a bearing element (12; 212; 312) which is pivotably supported at the piston (1; 201; 301) about a bearing element pivot axis (Y7) which extends parallel to the connecting rod pivot axes (Y5, Y6)

   characterized

   - in that the assembly including the two crankshafts (3, 4) rotating synchronously in opposite directions is configured in such a manner that the crank pins (32, 42) rotate in opposite directions, but with a slight asymmetry, already in a new condition when no wear and tear occured.
2. The twin crankshaft piston engine according to claim 1,
   characterized
   in that the asymmetry of the rotation of the crank pins (32, 42) is 5° at the most, preferably between 1° and 3°, further preferably 2°.
3. The twin crankshaft piston engine according to claim 1,
   characterized
   in that the asymmetry of the rotation of the crank pins (32, 42) is based on an offset of 1 to 6 teeth between meshing synchronization gears (30, 40) respectively disposed an the first crankshaft and an the second crankshaft.
4. The twin crankshaft piston engine according to claim 1, 2 or 3,
   characterized
   in that the bearing pivot axis (Y7) is respectively offset equidistant from the connecting rod pivot axes (Y5, Y6) in a pivot plane (E1) orthogonal to the bearing element pivot axis.
5. The twin crankshaft piston engine according to claim 4,
   characterized
   in that the bearing element pivot axis (Y7) is disposed in the center of a straight line (G) connecting the connecting rod pivot axes (Y5, Y6) in the pivot plane (E1) with one another.
6. The twin crankshaft piston engine according to claim 1,
   characterized

   - in that the bearing element (12; 212; 312) includes a circular contour (13; 213) or two contours (312", 312 "') in form of a segment of a circle, preferably disposed symmetrically to each other, whose circle center is disposed on the bearing element pivot axis (Y7),]

   - in that the piston (1; 201; 301) includes an adapted circular contour (15; 215') or adapted contours (315', 315") in form of a segment of a circle, respectively, whose circle center is also disposed on the bearing element pivot axis (Y7), and

   - in that the circular contour or the contours in form of a segment of a circle, respectively, (13; 213; 312", 312"') of the bearing element (12; 212; 312) and the circular contour or the contours in form of a segment of a circle, respectively, (15; 215'; 315', 315") of the piston (1; 201; 301) contact one another but are disposed moveable relative to one another about the bearing element pivot axis (Y7).
7. The twin crankshaft piston engine according to claim 6,
   characterized
   in that the bearing element (12; 312) is configured as a disc or a ring and the circular contour (13) is or the contours (312", 312"') in form of a segment of a circle, respectively, are configured at an outer circumferential edge of the bearing element (12; 312).
8. The twin crankshaft piston engine according to claim 6,
   characterized
   in that the bearing element (212) is configured as a ring and the circular contour (213) is or the contours in form of a segment of a circle, respectively, are configured at an inner circumferential edge of the bearing element (212).

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