EP3088701B1 - Piston with pivot bearings and double crankshaft piston engine - Google Patents

Description

The present invention relates to a piston, in particular for a piston-cylin- unit, with two pivot bearings for articulated mounting each of a connecting rod on the piston according to the preamble of claim 1. It further relates to a double crankshaft piston engine.

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 clearance between the intermeshing teeth of the synchronization gears occur, which in turn a slight asymmetry of the circulation of the crankshafts causes, 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". This asymmetry, as has already been stated, at the top dead center of the piston, a tilting moment is exerted on one side towards the piston and in the bottom dead center of the piston a corresponding tilting moment on 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, in order to avoid a clearance between the tooth flanks to store the two crankshafts in a common bearing block and to select the material of the bearing block and the material of the crankshafts and the synchronization gears in terms of their thermal expansion coefficient so that the thermal expansion of the bearing block between the two Rotation axes of the crankshaft 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 BE 423799 deals with a reciprocating engine in which two connecting rods are mounted on a reciprocating piston. These interact on the one hand with two crankshafts, which rotate in opposite directions. The piston-side connecting rods of the connecting rods are interposed piston pin with a bearing element which is inserted in a rotatable relative to a bore of the piston.

PRESENTATION OF THE INVENTION

Object of the present invention is to provide a generic piston, which is designed for a double crankshaft piston engine and which is tolerant to a wear-related asymmetrical barrel of the piston drive. A further object is to provide a double crankshaft piston engine which is tolerant of a wear-related slightly asymmetrical running of the two crankshafts.

The gerichetete on the piston object is achieved by the piston specified in claim 1.

In this piston, which is provided with two pivot bearings for articulated storage of a connecting rod about a respective Pleuelschwenkachse, the Pleuelschwenkachsen parallel to each other and laterally spaced from each other, the pivot bearings are provided on a bearing element which is pivotally mounted on the piston about a Lagerschwenkachse, which runs parallel to the connecting rod pivot axes.

ADVANTAGES

This according to the invention additionally provided over the prior art bearing element can rotate in a nonuniformity of the connecting rod, so with an asymmetry of the circulation of the crankshaft, relative to the piston and thus compensates for the asymmetry of the circulation of the two crankshafts, without the piston with its piston longitudinal axis is tilted with respect to the cylinder axis.

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 nicht erfindungsgemäßen Kolbens;

Fig. 4

eine teilweise geschnittene Stirnansicht einer dritten Ausführungsform eines nicht 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 non-inventive piston;

Fig. 4

a partially sectioned end view of a third embodiment of a non-inventive piston 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 corresponding cylinder axis X is received axially displaceable. Inside the cylinder 2, bounded by the cylinder 2 with its cylinder head 22 and a piston head 18 of the piston 1, a compression space 22 is formed. The piston 1 and the cylinder 2 form a piston-cylinder unit of the double crankshaft piston engine, which may be designed either as an internal combustion engine or as a compressor. The invention is not limited to a double crankshaft piston engine with only one piston-cylinder unit. The machine may also have more than one such piston-cylinder unit. Such reciprocating engines are well known to those skilled in the art, so that general components, such as valves or a valve control are not shown in the figures.

In Fig. 1 are further shown two crankshafts 3 and 4 of the crank mechanism of the double crankshaft piston engine, each having a synchronization gear 30, 40. The axes of rotation Y1, Y2 of the two crankshafts 3, 4 are parallel to a cylinder center plane E2 and with respect to this laterally offset, ie on opposite sides of the cylinder center plane E2, located. The synchronizing gears 30, 40 mesh with each other and simultaneously rotate in opposite directions at the same rotational speed (synchronous), as indicated by the arrows R1 and R2.

On the respective crankshaft 3, 4 or on the respective synchronization gear 30, 40, a bearing pin 32, 42 is formed eccentrically to the rotation axis Y1, Y2 of the respective crankshaft 3, 4, on each of which a connecting rod 5, 6 with a connecting rod eye formed at its lower end 50, 60 is rotatably mounted about a lower Pleuelaugenachse Y3, Y4.

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 are formed for the respective connecting rod shank 52, 62 of the connecting rod 5, 6. The extent of the passage openings 124, 125 in the circumferential direction of the bearing element 12 is dimensioned such that the connecting rods 5, 6 neither pivot about the axes Y5, Y6 during their pivotal movement 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 shows a further embodiment of a piston not according to the invention and a piston machine not according to the invention, in which the bearing element 312 has the shape of two adjacent in the region of the piston and cylinder axis X 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 greater than the vertical dimensions Dimensions of the bearing element 312, so that above and below the inserted into the aperture opening 315 bearing member 312 is sufficient space so that the bearing element 312 in the through hole 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 crank shaft-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 represented 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, no pendulum movement of the bearing body 12 occurs in the bore 15 of the piston 1 until a occurring between the teeth of the synchronization gears 30, 40 wear leads to the asymmetry already described, 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 a 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 to be 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.

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

Kömpressionsraum

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

warehouses 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 (2)

1. Piston, comprising two pivot bearings (55; 65) for pivotably bearing, in each case, a connecting rod (5; 6) on the piston (1) about a corresponding connecting rod axis (Y5 and Y6), the two connecting rod pivot axes (Y5 and Y6) extending parallel to and laterally spaced apart from one another, which piston (1), by means of the connecting rods (5; 6), drives two crankshafts (3; 4) that rotate in opposite directions, which two pivot bearings (55; 56) are provided on a bearing element (12) that is pivotably mounted on the piston (1) about a bearing pivot axis (Y7) which extends parallel to the connecting rod pivot axes (Y5; Y6), and the bearing element (12) having a circular cylindrical outer contour (13) that is received by a bore (15) on the piston (1), the bore (15) being formed in a lower projection portion of the piston (1), which projection portion (17) consists of a piece together with the piston (1) and the bearing element (17) having two wall portions (12'; 12") facing away from one another on the end face, which wall portions are spaced apart from one another in the direction of the connecting rod pivot axes (Y5; Y6) and form an gap with which the corresponding connecting rod (5; 6) engages, characterized in that the wall portions (12', 12") on the end face are interconnected only via an upper projection (120), a lower projection (121) and lateral circumferential portions (122; 123), through-openings (124; 125) for the corresponding connecting rod shank (52; 62) of the connecting rod (5; 6) being formed along the circumference of the bearing elements (12'; 12") between the lower projection (121) and the corresponding circumferential wall portions (122, 123).
2. Piston according to claim 1, characterized in that the gap for the connecting rods (5, 6) is delimited by partial wall portions of the bearing element (12), which partial wall portions extend apart from one another in a V-shape at least in the direction of the lower projection (121) in such a way that broadenings of the bearing element (12) are produced adjacent to the piston-side connecting rod bearing pin (16) between the wall portions (12', 12') on the end face and the partial wall portions of the gap, which broadenings delimit an upper connecting rod eye (64) of the connecting rod (5, 6).

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