Crank drive of an engine or a compressor

Abstract

Crank mechanism (100) of an engine or a compressor, comprising • several cylinders (25) with pistons (13) mounted in them in respective stroke axes (13.1, 13.2) so as to be movable, • a crankshaft (5) rotatable about a rotational axis (5.1) with at least one crank axis (6) offset eccentrically to the rotational axis (5.1), wherein • the crank mechanism has a connecting rod element (9) formed with several articulation points (A1, A2, A3, A4), wherein • a guide element (3) is arranged which is guided in a guide means (2) fixed to the housing in a stroke-movable manner, wherein the connecting rod element (9) is connected to the guide element (3) at a third articulation point (A3), and wherein • the connecting rod element (9) has a fourth articulation point (A4) in which the connecting rod element (9) is connected to the crank axis (6) of the crankshaft (5) which is offset eccentrically to the axis of rotation (5.1), • so that the connecting rod element (9) performs a reciprocating motion when the crankshaft (5) rotates about the axis of rotation (5.1), characterized in that • four cylinders (25) are arranged which are arranged in a rectangular formation relative to one another along the stroke axes (13.1, 13.2) of the pistons (13), wherein • two first pistons (13) in first cylinders (25) are connected to the connecting rod element (9) by means of first connecting rods (4) at first articulation points (A1) and • two second pistons (13) in second cylinders (25) are connected to the connecting rod element (9) by means of second connecting rods (4) at second articulation points (A2), wherein • the connecting rod element (9) forms two symmetrically arranged side parts (10) which are firmly connected to one another by a solid body (11), and wherein • the connecting rod element (9) is arranged such that the axis of rotation (5.1) of the rotatable crankshaft (5) is arranged at a height between the articulation points (A1, A2) of the push rods (4) on the connecting rod element (9) and the arrangement of the pistons (13), as seen along the push rods (4).

Description

[0001] The invention relates to a crank mechanism according to the preamble of claim 1 and a device equipped therewith in the form of an engine, preferably an internal combustion engine, or a compressor according to the preamble of claim 11. STATE OF THE ART

[0002] In internal combustion engines and compressors, for example, the crank drive has prevailed over rotary piston engines. A compressive force exerted on a piston due to the expansion of combustion gases along its linear movement in a cylinder housing along its inner wall is broken down into a push rod force acting on a push rod hinged underneath, and a transverse force acting from the piston essentially perpendicularly on the inner wall of the cylinder housing guiding the piston. At a connecting rod element pivot point of a crank pin of a crankshaft, the push rod force is broken down into a tangential force and a radial force. The tangential force lies on a tangent to a circular line along which the crank pivot point moves about a rotational axis of the crankshaft, thereby causing the crankshaft to rotate about the rotational axis. The radial force is directed from the crank pivot point towards the rotational axis.All of these forces are typically transmitted via plain bearings. One resulting disadvantage is frictional losses. The greatest frictional losses occur between the pistons and the inner wall of the associated cylinder housing. Furthermore, this leads to significant wear on the pistons and cylinders, which shortens their service life. Another disadvantage is the vibration throughout the entire machine caused by the movement of the push rods, especially considering the large radius of the aforementioned circular line in relation to the width dimensions of the pistons perpendicular to their linear movement. A further disadvantage is the design of a multi-cylinder machine, which prevents the use of low-friction rolling bearings. At least the first two disadvantages mentioned also exist in compressors.

[0003] It is therefore the object of the present invention to provide a crank drive for an engine or a compressor which substantially overcomes the disadvantages of the prior art and has significantly lower wear and lower internal friction, and which in particular also leads to lower vibrations.

[0004] CH 548 537 A describes a crank mechanism with multiple cylinders, with the individual crank mechanism of each cylinder being equipped with a crosshead to which a connecting rod is pivoted, one end of which is mounted on a crankshaft journal. The connecting rods of the cylinders are each divided into a piston rod and a connecting rod, which are pivotally connected to each other. The piston rod is connected to a piston at its other end, and the connecting rod is connected to the crankshaft at its other end.

[0005] DE 23 47 888 A1 discloses a crank mechanism of an internal combustion engine, comprising two cylinders with pistons accommodated therein in respective stroke axes so as to be movable in stroke, a crankshaft rotatable about an axis of rotation with at least one crank axis offset eccentrically to the axis of rotation, wherein the crank mechanism has a connecting rod element formed with a plurality of articulation points, wherein a guide element guided so as to be movable in stroke in a guide means fixed to the housing is arranged, wherein the connecting rod element is connected to the guide element at an articulation point, and wherein the connecting rod element has an articulation point at which the connecting rod element is connected to the crank axis of the crankshaft, which is offset eccentrically to the axis of rotation, so that the connecting rod element executes a stroke-pendulum movement when the crankshaft rotates about the axis of rotation.

[0006] Another crankshaft drive of an internal combustion engine is known from DE 10 2015 013 489 A1. DISCLOSURE OF THE INVENTION

[0007] This object is achieved based on a crank mechanism according to the preamble of claim 1 and a device according to the preamble of claim 11, each in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims.

[0008] The invention includes the technical teaching that four cylinders are set up which are arranged in a rectangular formation relative to one another as seen along the stroke axes of the pistons, wherein two first pistons in first cylinders are connected to the connecting rod element by means of a first push rod at first articulation points, and wherein two second pistons in second cylinders are connected to the connecting rod element by means of second push rods at second articulation points, for which purpose the connecting rod element forms two symmetrically arranged side parts which are firmly connected to one another at a distance from the fourth articulation point by a solid body, and wherein the connecting rod element is set up such that the axis of rotation of the rotatable crankshaft is arranged at a height between the articulation points of the push rods on the connecting rod element and the arrangement of the pistons as seen along the push rods.

[0009] The invention thus provides a connecting rod element which is approximately triangular or triangular in shape when viewed from the axis of rotation, which has two articulation points formed at a distance from one another for connecting the pistons, which is connected to a guide element which is guided in a linearly movable manner and to which a crank axis of a crankshaft is connected.

[0010] The first two pistons are connected to the connecting rod element by means of first push rods at first articulation points and the two second pistons are accordingly connected to the connecting rod element by means of second push rods at second articulation points, wherein the push rods run parallel to each other or at least enclose only a small angle to each other.

[0011] The connecting rod element is guided linearly by the guide element on a guide means transverse to the axis of rotation and preferably parallel to the direction of stroke of the pistons and is connected to the crank pin of the crankshaft, so that the connecting rod element executes a reciprocating pendulum movement when the crankshaft rotates in the axis of rotation. The connecting rod element forms an intermediate link between the push rods of the pistons and the crankshaft, which is formed with the crank axis, wherein the crank axis is, for example, connected integrally to the crankshaft and can be referred to as the reciprocating axis or crank pin. The reciprocating pendulum movement of the connecting rod element means that the push rods of the associated pistons, which are connected to the connecting rod element at a distance from one another, are deflected to a much lesser extent than in conventional crank drives. This means thatAccording to the invention, the connecting rod element, with its reciprocating pendulum movement, assumes part or even all of the deflection of push rods traditionally connected to a crank pin. This enormously reduces the transverse force on the respective piston, with which the piston presses against the cylinder wall from the inside during each power stroke. This, in turn, leads to significantly less wear, lower frictional forces, and significantly reduced vibrations. Furthermore, this design enables the use of rolling bearings instead of plain bearings for the entire crank mechanism, since the forces to be absorbed are lower, which is what makes the use of rolling bearings possible in the first place. The fourth articulation point connects the connecting rod element to the crankshaft's crank axis, which is offset eccentrically to the axis of rotation, which makes the output and the conversion of the connecting rod movement into a rotary movement of the crankshaft possible in the first place. The connecting line between the third articulation point and the fourth articulation point runs perpendicular to the connecting line between the first articulation point and the second articulation point of the linkages of the push rods and thus the connection of the pistons. The push rods are preferably arranged with a first end so that they can swing on the associated piston and with a second end so that they can swing on the connecting rod element at the associated articulation point. This means thatthe push rods are linked to the respective piston in the classic way, but preferably carry out a reciprocating movement in their longitudinal direction and, on the other hand, hardly carry out a pendulum movement, especially because the connecting rod element is designed in such a way that the axis of rotation of the rotatable crankshaft, seen along the push rods, is arranged at a height between the articulation points of the push rods on the connecting rod element and the arrangement of the pistons.

[0012] By operating the connecting rod element in this way, the resulting transverse force between the pistons and the inner walls of the cylinders is reduced, as are the lateral forces acting on the connecting rod element. Thus, for example, the forces between the guide element and the guide means are also low, since all acting forces run essentially parallel to the stroke axes of the connecting rod elements. The connection between the connecting rod element and the guide element preferably comprises a joint connection with a joint pin, and / or the connection between the connecting rod element and the crank axis is provided with a pivot bearing.

[0013] The third pivot point on the connecting rod element is located spatially between the first and second pivot points, to which the guide element is connected with a pivot pin that extends parallel to the axis of rotation, whereby the guide element is guided linearly in the stroke direction of the pistons on its own stroke axis on a linear device. At a certain distance, the connecting rod element has the fourth pivot point on its center line, which lies above or below the third pivot point with respect to the stroke axes. At the fourth pivot point, the connecting rod element is rotatably connected to the crank axis. When the crankshaft rotates, the connecting rod element rotates on the crank axis and at the third pivot point the connecting rod element is guided back and forth linearly. As a result, the push rods of the first and second pivot points are also guided almost linearly. The piston force acting on the push rods is split into two forces at the first pivot point.One force runs along the line connecting the first pivot point to the fourth pivot point, which is then broken down at the fourth pivot point into a radial force and a tangential force (rotational force of the crankshaft). The second broken down force acts along the line connecting the first pivot point to the third pivot point. The second broken down force is then broken down into two forces at the third pivot point. One force acts perpendicular to the axis of the linear guide, and the second force acts along the axis of the linear guide.

[0014] The forces of the second push rod are also split into two forces at the second pivot point. The first force acts along the line connecting the second pivot point to the fourth pivot point, which is in turn split at the pivot point into a radial force and a tangential force (rotational force of the crankshaft). The second force acts along the line connecting the third pivot point to the second pivot point. The second split force is split into two forces at the third pivot point. One force acts perpendicular to the axis of the linear guide. The other acts along the axis of the linear guide.

[0015] The almost linearly guided push rods relieve the cylinder walls of the load required for power transmission. This, in turn, leads to significantly lower frictional forces and vibrations. Furthermore, this design allows the use of rolling bearings instead of plain bearings, which in turn reduces power losses.

[0016] Additionally or alternatively, the guide means for linearly guiding the connecting rod element and the rotational axis of the crankshaft can each be arranged centrally between the connecting rod element's pivot points in the stroke direction. This results in the same forces acting on both piston-push rod assemblies. This allows the components for the piston assemblies to be dimensioned identically, enabling the cost-effective use of identical parts.

[0017] In all of the aforementioned crankshaft drives, the piston stroke directions are preferably parallel to each other. This allows for classic cylinder block arrangements in a row, in a rectangle, or, as in a boxer engine, opposite each other relative to the crankshaft.

[0018] Alternatively or additionally, the push rods are provided with lubricating devices in the area of the pivot points, which benefits their longevity and ease of maintenance. The connecting rod element can also be rotatably connected to the crankshaft in the area of its linear guide at its center of gravity as a crank pivot point and, in another area, can be articulated to a part that is guided internally or externally in a stationary, linear guide means. This position of the center of gravity reduces the vibrations caused by the connecting rod element and enables particularly energy-saving power transmission from the connected push rods to the connecting rod element or vice versa. It can therefore be stated that the connecting rod element has a center of gravity that coincides with the connection between the connecting rod element and the crank axis, and the connection between the connecting rod element and the guide element is at a distance from the center of gravity.

[0019] According to the invention, the connecting rod element is designed symmetrically along the axis of rotation. Viewed transversely to the axis of rotation, the connecting rod element has two symmetrically arranged side parts, which are firmly connected to one another by a solid body at a specific distance in the area of the crank pivot point. Both measures, individually or in combination, result in equal forces on the connected push rods, combined with the advantages already mentioned. Bearings are preferably installed in the side parts at the center of gravity of the connecting rod element, ensuring a freely rotatable connection at the crank pivot point. This serves to reduce friction losses.

[0020] Recesses, each with two threaded holes, can be formed along a center line of the connecting rod element at a specific distance from the center of gravity in the direction of the articulation points. These holes are intended for insertion and screwing into connecting rod bearing flanges or connecting rod axle flanges. Finally, viewed in the direction of the axis of rotation, bearings provided with axles can be installed to the left and right perpendicular to the center line of the connecting rod element from the axis of the connecting rod bearing flanges at a specific distance. All of this also serves to reduce friction. The connecting rod element is thus articulated to the guide element by means of connecting rod bearing flanges arranged thereon and / or the stationary guide means is arranged with a base plate on a side of the crankcase facing away from the piston.

[0021] In the latter two crankshaft drives, in the case of an externally mounted linear guide, the guide element can be pivotally connected to the connecting rod bearing flanges, and the stationary guide, formed by the guide means, can be attached to the housing on a side facing away from the piston. This allows for simple assembly and thus easy installation in the crankcase.

[0022] The guide means can thus be a hollow cylinder with parallel surfaces formed on both sides. The joint axis is firmly seated in the center of the hollow cylinder, essentially perpendicular to the flat surfaces, and is provided with thrust washers on both sides. This enables a simple and therefore cost-effective linear guide along the stationary guide, which benefits operational reliability. Thus, the guide means can have a receiving cylinder that is structurally integral with the base plate of the guide means and in which the cylindrical guide element is accommodated.

[0023] Alternatively or additionally, the guide means forms a cylinder with parallel, machined surfaces on both sides and, in particular, is integrated into a base plate provided with screw holes on both sides. This is also an easy-to-manufacture and therefore cost-effective way to provide a linear guide. If the hollow cylinder also has machined surfaces, as stated, the linear guide can be manufactured in a torsion-proof manner simply by pushing the hollow cylinder and cylinder together, so that the connecting rod element is securely guided and can always be moved by the push rods.

[0024] In the case of an internally arranged, linear guide, the reciprocating part of the guide can be articulated to axes of connecting rod axis flanges of the connecting rod element. The guide forms a guide pin that is firmly connected to a base plate. The base plate is screwed to the underside of a crankcase or itself forms the bottom section of the entire housing. This is an easily manufactured alternative to an externally arranged, linear guide device. The housing is formed at least from a top cylinder plate in which the cylinders are formed, the crankcase in which the crankshaft is mounted so that it can rotate freely about the axis of rotation, and the base plate of the guide means arranged on the bottom or a base plate covering the underside of the base plate.

[0025] In the last two crank mechanisms, the guide of the guided part can form a guide pin, which is firmly connected to the base plate, which is provided with screw holes on both sides.

[0026] According to the invention, each aforementioned crank mechanism has four pistons, thus providing an even number of pistons. This promotes smooth running, and four pistons enable a rectangular formation or arrangement of the pistons, since their stroke directions run parallel to each other.

[0027] The housing preferably comprises a cylinder block in which the cylinder housings are formed, and an adjoining crankcase in which the crankshaft is accommodated. The housing is designed such that the stroke directions of the pistons are aligned perpendicular to a connecting surface of the cylinder block with the crankcase. Conventionally designed crankcases can therefore continue to be used.

[0028] Since the crankshaft has an even number of pistons, and these pistons run parallel to each other in their stroke directions, the corresponding cylinder housings are arranged in a rectangular formation, as seen along the stroke directions of the pistons. This is a particularly space-saving arrangement compared to conventional V-engines, for example.

[0029] The invention further provides a device configured as a motor or compressor. According to the invention, the device comprises one of the aforementioned crank mechanisms. Its crankshaft forms an engine output shaft or a compressor drive shaft, depending on the configuration of the device.

[0030] The distance between the first pivot point and the second pivot point may be equal to the distance between the first stroke axis of the first piston and the second stroke axis of the second piston. PREFERRED EMBODIMENTS OF THE INVENTION

[0031] Further measures improving the invention are described in more detail below, together with the description of preferred embodiments of the invention, with reference to the figures. They show: Fig. 1 and Fig. 2 two views of a crank mechanism according to a first embodiment of the invention, Fig. 3 to 6 the pistons together with push rod and connecting rod element of Fig. 1 in one of four operating positions, Fig. 7 and Fig. 8 two views of one of the push rods and the pistons rotated 90° to each other, Fig. 9 and Fig. 10 two views of a crank mechanism according to a second embodiment of the invention, Fig. 11 and Fig. 12 two views of a crank mechanism according to the embodiment of Fig. 1 and Fig. 2 of the invention, Fig. 13a, Fig. 13b an internal guide of the connecting rod element on the base plate and Fig. 14a, Fig. 14b an external guide of the connecting rod element on the base plate.

[0032] Fig. 1 shows a crank mechanism 100 according to a first embodiment of the invention in a sectional view transverse to the axis of rotation 5.1, and Fig. 2 shows the same embodiment of the crank mechanism 100 in a sectional view along a rotation axis 5.1 through the connecting rod element 9.

[0033] The crank mechanism 100 comprises four pistons 13, each mounted for linear movement along a respective stroke axes 13.1 and 13.2, which are guided in associated cylinders 25, whereby only two pistons 13 are shown in the sectional view. The cylinders 25 are formed in a cylinder plate 16, onto which a respective cylinder head is mounted in a manner not shown in detail. The entire housing of the crank mechanism 100 is constructed from the upper cylinder plate 16, in which the cylinders 25 are formed, a crankcase 21, in which the crankshaft 5 is mounted so as to be freely rotatable about the rotation axis 5.1, and a base plate 22 arranged on the bottom side.

[0034] A crankshaft 5 is rotatably mounted around the rotational axis 5.1 and is designed with a crank axis 6 offset eccentrically to the rotational axis 5.1. According to the invention, the crank drive 100 has a connecting rod element 9 designed with four articulation points A1, A2, A3 and A4, wherein the first piston 13 is connected to the connecting rod element 9 by means of a first push rod 4 at a first articulation point A1, the second piston 13 is connected to the connecting rod element 9 by means of a second push rod 4 at a second articulation point A2, and wherein a guide element 3 is guided in a guide means 2 fixed to the housing, wherein the connecting rod element 9 is connected to the guide element 3 at a third articulation point A3, so that the connecting rod element 9 executes a reciprocating pendulum movement when the crankshaft 5 rotates about the rotational axis 5.1.

[0035] The connecting rod element 9 has a fourth articulation point A4, in which the connecting rod element 9 is connected to the crank axis 6 of the crankshaft 5, which is offset eccentrically to the rotation axis 5.1.

[0036] Below each piston 13, a push rod 4 is mounted either stationary or pivoted about an axis perpendicular to the plane of the page. The push rods 4 can be rigid or flexible. The push rods 4 are located, for example, in the crankcase 21, which adjoins the underside of the cylinder plate 16. The push rods 4 are pivoted to the connecting rod element 9 at their ends facing away from the respective piston 13 by means of associated connecting rod pins 14. The push rods 4 engage the connecting rod element 9 at the pivot points A1 and A2 on two opposite side areas of the connecting rod element 9. Below each push rod 4 is a lubricating device 23 that ensures low-friction operation of the associated push rod 4 and projects into an oil sump. The lubricating devices 23 are simply constructed with a lubricating cup and a screw element.

[0037] The connecting rod element 9 is connected with its fork-shaped connecting rod bearing flanges 8 by means of a hinge pin 15 via pivot bearings 26 to a guide element 3, wherein the guide element 3 is linearly guided in a guide means 2 along a stroke axis H. The guide means 2 has a receiving cylinder 28 in which the guide element 3 is guided. The receiving cylinder 28 is received on a base plate 20 and extends perpendicularly out of the base plate 20 along the stroke axis H, wherein the base plate 20 runs parallel to the base plate 22. Due to the guide means 2, the connecting rod element 9 can execute a stroke-pendulum movement when the crankshaft 5 rotates, in that the crank axis 6, which is formed eccentrically to the rotation axis 5.1 on the crankshaft 5, allows the center of gravity S of the connecting rod element 9 to rotate about the rotation axis 5.1 during rotation.

[0038] In the upper area of the connecting rod element 9, facing the piston 13 in the position shown, there are mass balancing sections 7 on a crankshaft 5. Slightly below the mass balancing sections 7, the connecting rod element 9 is freely rotatably connected to the crankshaft 5 or the crank axis 6. The axis of rotation 5.1 of the crankshaft 5 also runs perpendicular to the plane of the page.

[0039] The respective pairing of push rod 4 - connecting rod element 9 thus replaces a conventional connecting rod. If the crank mechanism is part of an engine, for example, the left pistons 13 are moved up and down with the attached push rod 4 and the connecting rod element 9 is pivoted back and forth via this movement. The crankshaft 5 is set in rotation by the guide 1 and the upper connection to the crankshaft 5. The special arrangement of the articulation point A1, A2 of the push rod 4 on the connecting rod element 9 for the crankshaft connection of the connecting rod element 9 results in this articulation point A1, A2 experiencing a significantly smaller horizontal deflection than the point at which the connecting rod element 9 is connected to the crankshaft 5 via the crank axis 6. This also reduces the induced Fig. 1 horizontal transverse forces between the pistons 13 and the guide wall of the corresponding cylinder 25.

[0040] The pivot bearing 26 is preferably designed as a roller bearing; preferably, all of the pivot points A1 to A4 on the connecting rod element 9 are designed as roller bearings. The base plate 20 is preferably screwed to the underside of the crankcase 21.

[0041] The mass balancing section 7 is formed by two projections that are fixedly arranged on the crankshaft 5 and protrude from the crankshaft 5, preferably in the same direction, transverse to the rotational axis 5.1 of the crankshaft 5. The balancing section 7 serves the purpose of compensating for vibrations, shocks, and imbalances on the rotating crankshaft 5.

[0042] The Fig. 3 to 6 show the pistons 13 together with push rods 4 and connecting rod element 9 in one of four operating positions. According to Fig. 3, the right-hand pistons 13 are at their top dead center and the left-hand pistons 13 are lower, but above bottom dead center. The connecting rod elements 9 are pivoted to the left by a maximum pendulum angle β via the right-hand push rods 4. The articulation point of the connecting rod element 9 on the associated crank axis 6 of the crankshaft 5 is located to the left above the axis of rotation of the crankshaft 5. The vertical linear guidance of the connecting rod element 9 is achieved by means of the guide element 3, which is guided on a guide pin 18 projecting upwards from a base plate 20. The connecting rod element 9 is articulated on the guide element 3 so that it can rotate freely. From a functional point of view, the connecting rod element 9 forms a secondary connecting rod 29 or 30 between each pairing of articulation point A1, A2 to push rod 4 - articulation point crankshaft 5. On the left and right in the views, two pistons 13 in two cylinders 25 and two push rods 4 each lie one above the other in the image plane.

[0043] If the right pistons 13 move downwards and the left pistons 13 move upwards, the Fig. 4, in which the left pistons 13 are at top dead center. The connecting rod element 9 is pivoted to the right by the same amount of pendulum angle β.

[0044] If the right pistons 13 are moved downwards to the maximum, the Fig. 5, in which the left pistons 13 have also been moved downwards a little. The articulation point of the connecting rod element 9 on the corresponding crank axis 6 of the crankshaft 5 is located to the right below the rotation axis of the crankshaft 5. Due to its vertical downward movement, the connecting rod element 9 is again pivoted to the right, preferably as far as in Fig. 4. The downward movement is caused by the rotation of the crankshaft 5.

[0045] If the left pistons 13 have reached the bottom dead center, the Fig. 6. The crank axis 6 is located to the left below the rotational axis of the crankshaft 5, and the connecting rod element 9 is pivoted to the left. The entire process is then repeated. The reference symbol Ls denotes a respective shoulder length, which describes the distance between the pivoting or rotational axis of the connecting rod element 9 and the rotational axis of one of the push rods 4. From the Fig. 3 to 6 it becomes clear how little the push rods 4 are deflected horizontally.

[0046] Fig. Figure 7 shows a view of an arrangement comprising a piston 13 and the push rod 4 attached thereto, analogous to Fig. 1. Fig. 8 shows the arrangement in a view from the left in Fig. 7. The push rod 4 is preferably clamped or otherwise fastened to the piston 13 at the top, but can also be pivoted about a rotational axis parallel to the rotational axis of the crankshaft 5 (not shown here). In the lower area there are two legs 31 which, together with the rest of the push rod 4, form a U-shaped receiving fork pointing away from the piston 13. A through opening 27 is formed in each leg 31. The through openings 27 are preferably aligned with one another in order to accommodate the connecting rod bolts 14. Below each leg 31 there is a lubricating device 23 for the push rod 4. A lubricating device 23 is also preferably provided in the piston area.

[0047] Fig. 9 shows a crank mechanism 100 according to a second embodiment of the invention in a partial sectional view. Fig. 10 shows this crank mechanism 100 also in a partial sectional view from the left in Fig. 9. The connecting rod element 9 essentially consists of two side parts 10, which are fixedly attached or formed on a solid body 11 connecting them at a certain distance above the center of gravity of the connecting rod element 9.

[0048] The side parts 10, 10 are rotatably connected to a reciprocating lifting part 17 via two connecting rod axes 19 designed as semi-axles, which is guided vertically and linearly on the outside in a preferably sleeve-like part. The crank axis 6, the connecting rod axes 19, 19, and the axes with which the push rods 4 (not shown) are articulated to the connecting rod element 9 are received in pivot bearings 26 that are fixedly inserted in the respective side part 10. The pivot bearings 26 are preferably roller bearings, in particular ball bearings. The side parts 10 are preferably designed symmetrically. After the production of the connecting rod element 9 and the push rods 4, deviations from calculated and actual masses may arise. Therefore, threaded holes are preferably provided on the solid body 11 to the left and right of the center line of the connecting rod element 9, into which screws 12 or threaded pins are screwed.

[0049] By adjusting the position of the screws 12 or threaded pins in the threaded holes, balancing in the connecting rod element 9 can be carried out relatively easily. Bearing seats for the connection to the axle 6 of the crankshaft 5 are arranged on the two side parts 10, preferably at the center of gravity of the connecting rod element 9. Recesses, each provided with two threaded holes, are provided on the side parts 10 on a vertical centerline of the connecting rod element 9, at a specific distance downwards from the center of gravity. The connecting rod bearing flanges 8 or connecting rod axle flanges 24 are inserted into the recesses and screwed into place. The connecting rod element 9 is connected to the connecting rod axles 19 via a connecting rod axle flange 24.

[0050] Fig. 11 shows a crank mechanism 100 according to a third embodiment of the invention in a partial sectional view. Fig. 12 shows this crank mechanism 100 in a partial sectional view from the left in Fig. 11. The crank mechanism 100 is very similar to the second embodiment. However, here, the connecting rod element 9 has a receiving cylinder 28 and a continuous pivot pin 15.

[0051] The Fig. 13a and Fig. 13b show an internal guide of the guide element 3 or the lifting part 17, wherein in Fig. 13a a section is made through the articulation points A1, A2 with the flanges 32 and the articulation point A3, so that the connecting rod element 9 can also be seen in connection with the connecting rod bolts 14, furthermore the connecting rod bearing flanges 24 are shown in connection with the connecting rod axis 19 in the guide pin 18. The guide pin 18 extends as in Fig. 13b, protrudes vertically from the base plate 20 and projects into the guide element 3.

[0052] The Fig. 14a and Fig. 14b show an alternative external guide of the guide element 3 with an external guide of the guide element 3, wherein in Fig. 14a a section through the articulation points A1, A2 with the flanges 32 and the articulation point A3 is shown, so that the connecting rod element 9 can be seen in connection with the connecting rod pin 14, furthermore the hinge pin 15 is shown in connection with the connecting rod bearing flange 8. The guide means 2 extends as in the Fig. 14b, protrudes vertically from the base plate 20 and forms an inner cylinder in which the guide element 3 is accommodated in a lifting manner, the base plate 20 forming, for example, a part of the housing 1.

[0053] The invention is not limited to the embodiments described above.

[0054] If the number of pistons 13 is even, and preferably four, they can be arranged in a rectangular formation, viewed transversely to the axis of rotation of the crankshaft 5. The push rods 4 can be arranged perpendicular to a connecting surface between the cylinder plate 16 and the crankcase 21, which is designed to support the crankshaft 5 in the axis of rotation 5.1. The axis of rotation 5.1 can be fixedly connected to the respective crankpin on one side by a tongue and groove connection and displaceably connected to the crankpin on the other side by a tongue and groove connection. The center of gravity of the connecting rod element 9 is preferably the crank axis 6 of the crankshaft 5.

[0055] The pistons 13 are preferably driven by only one connecting rod element 9, particularly in the case of a four-cylinder crankshaft drive. Four secondary connecting rods 29, 30 are integrated into the connecting rod element 9. The distances from the axes 14 to the crankshaft 5 are a type of secondary connecting rod length. A single connecting rod element 9 has several advantages over a four-cylinder crankshaft drive with four connecting rods. The friction losses between the pistons 13 and cylinder 25, as well as the articulated connections of the push rods 4 to the connecting rod element 9, are almost zero. The linear guide 1 is well positioned for good lubrication. The crankshaft drive according to the invention is weight- and space-saving and also more cost-effective to manufacture. The forces acting on the linear guide are partially canceled out in the connecting rod element 9. Such a crankshaft drive can operate almost vibration-free.

[0056] One side wall of the crankcase 21 may be provided with a bearing seat. A side cover provided with a bearing seat may be attached to the other side.

[0057] The base plate 20 preferably has screw holes at both ends and is inserted and screwed into recesses on projections of the crankcase 21. The pistons 13 preferably have a slight conical shape from top to bottom in the direction of the connecting rod element 9, with an inclination of preferably approximately 1 / 300. As a result, only the part of the piston 13 located above the upper piston ring comes into contact with the cylinder wall. The conical shape of the pistons 13 prevents jamming of the pistons 13 in the respective cylinder 25, which can occur due to slight deviations of the lower part of the push rods 4 from the cylinder axes. The advantages of this piston design over pistons 13 with articulated connections to the push rods 4 are lower weight and lower manufacturing costs.

[0058] The lifting part 17 is preferably a cylinder with a through bore. A linear plain bearing is installed in the bore. Cylindrical surfaces are machined on both sides of the cylinder. Bores for the bearing seats are provided at the center of part 17, perpendicular to the machined surfaces. The connecting rod axes 19 are firmly connected to the connecting rod axis flange 24. The axis 15 can be mounted at the center of the cylinder, perpendicular to the machined surfaces, and is firmly connected to part 3. The pivot pin 15 is preferably provided with thrust washers on both sides. The guide is a bore integrated into the base plate 20. Both side surfaces of the bore are machined. The bore is provided with bearing shells, or the base plate 20 is made of materials with good sliding properties.

[0059] In conventional crank drives for compressors, the lower part of the push rod rotates into the oil in the oil pan and sprays the oil into the crankcase. This lubricates all bearings and cylinders in the crankcase. This lubrication method is problematic for the invention because the push rods 4, the guide element 3, and the side parts 10 of the connecting rod element 9 together form a large immersion surface. If this surface plunges linearly into the oil surface of the oil pan at high speed, undesirable impacts can occur on the oil surface of the oil pan. Therefore, it is provided that the lubricating device 23 for lubricating the cylinders, bearings of the guide, and pivot bearing 26 is provided in the crankcase 21. It comprises a container that is firmly connected with a screw. The lubricating devices 23 are advantageously screwed to the bearing flanges 8 and to the push rod flanges.At the bottom dead center of the respective piston 13, the cup of the corresponding lubrication device 23 is below the surface of the oil in the oil pan. As the piston 13 moves upwards away from the connecting rod element 9, the piston 13 changes from positive acceleration to negative acceleration, thus decelerating. This causes the contents of the cup to be ejected linearly into the cylinder chambers and bearing seats.

[0060] The connecting rod element 9 is advantageously designed so that the phases between in the Fig.9 to 12, the left and right connected pistons 13 are shifted by 90° at TDC. When the crankshaft 5 rotates clockwise and the respective crank axis 6 is at position 315°, then the right pistons 13 are at TDC, and the left pistons 13 have preferably reached half of their stroke towards TDC. When the crankshaft 5 is at position 45°, the connecting rod pin 14 to the left of the connecting rod element 9, as well as the rotational axis 5.1 and the crank axis 6, must be in line. In this position of the connecting rod element 9, the left piston is at TDC. By specifying a crankshaft lever r and the oscillation angle ß, all dimensions of the connecting rod element 9 can be calculated. For example, the following applies: r = 20 mm β = 6° Length of push rod 4: 135.29 mm Ls = 109.55 mm Cylinder center distance: 108.94 mm Piston stroke: 51.26 mm Deviations of axes 14 from the cylinder axes: ±0.6 mm β max = 8.5°.

[0061] If the pistons 13 have a diameter of 80 mm, the displacement for one cylinder is approximately 257.53 cm 3 The crank mechanism according to the invention is suitable for internal combustion engines and compressors of all types. Several crank mechanisms can be coupled together, whereby two four-cylinder crank mechanisms can form an eight-cylinder crank mechanism, which is suitable for an eight-stage high-pressure compressor for gases.

[0062] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the presented solution even in fundamentally different embodiments. All features and / or advantages apparent from the claims, the description, or the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations. List of reference symbols: 100 crank drive 1 housing 2 guidance tools 3 Guide element 4 push rod 5 Crankshaft 5.1 Rotation axis 6 Crank axle 7 Mass balancing section 8 connecting rod bearing flange 9 Connecting rod element 10 side panel 11 massive body 12 screw 13 pistons 13.1 Lifting axis 13.2 Lifting axis 14 connecting rod bolts 15 hinge pins 16 Cylinder plate 17 Lifting part 18 guide pins 19 Connecting rod axle 20 base plate 21 Crankcase 22 Base plate 23 Lubrication device 24 Connecting rod axle flange 25 cylinders 26 Pivot bearing 27 Passage opening 28 receiving cylinders 29 auxiliary connecting rods 30 auxiliary connecting rods 31 legs 32 flange β pendulum angle r crank distance Ls shoulder length S focus H lifting axis A1-A4 articulation point

Claims

[1] Crank mechanism (100) of an engine or a compressor, comprising • several cylinders (25) with pistons (13) mounted in them in respective stroke axes (13.1, 13.2) so as to be movable, • a crankshaft (5) rotatable about a rotational axis (5.1) with at least one crank axis (6) offset eccentrically to the rotational axis (5.1), wherein • the crank mechanism has a connecting rod element (9) formed with several articulation points (A1, A2, A3, A4), wherein • a guide element (3) is arranged which is guided in a guide means (2) fixed to the housing in a stroke-movable manner, wherein the connecting rod element (9) is connected to the guide element (3) at a third articulation point (A3), and wherein • the connecting rod element (9) has a fourth articulation point (A4) in which the connecting rod element (9) is connected to the crank axis (6) of the crankshaft (5) which is offset eccentrically to the axis of rotation (5.1), • so that the connecting rod element (9) performs a reciprocating motion when the crankshaft (5) rotates around the axis of rotation (5.1), characterized by , that • four cylinders (25) are arranged which are arranged in a rectangular formation relative to one another along the stroke axes (13.1, 13.2) of the pistons (13), wherein • two first pistons (13) in first cylinders (25) are connected to the connecting rod element (9) by means of first connecting rods (4) at first articulation points (A1) and • two second pistons (13) in second cylinders (25) are connected to the connecting rod element (9) by means of second connecting rods (4) at second articulation points (A2), wherein • the connecting rod element (9) forms two symmetrically arranged side parts (10) which are firmly connected to one another by a solid body (11), and wherein • the connecting rod element (9) is arranged such that the axis of rotation (5.1) of the rotatable crankshaft (5) is arranged at a height between the articulation points (A1, A2) of the push rods (4) on the connecting rod element (9) and the arrangement of the pistons (13), as seen along the push rods (4). [2] Crank drive (100) according to claim 1, characterized by that the push rods (4) are arranged with a first end fixed or articulated on the associated piston (13) and with a second end articulated on the connecting rod element (9) at the associated articulation point (A1, A2). [3] Crank mechanism (100) according to one of the preceding claims, characterized by that the connection between the connecting rod element (9) and the guide element (3) has a joint connection with a joint pin (15) and / or that the connection between the connecting rod element (9) and the crank axle (6) has a further pivot bearing. [4] Crank mechanism (100) according to one of the preceding claims, characterized bythat the connecting rod element (9) has a center of gravity (S) which coincides with the connection between the connecting rod element (9) and the crank axis (6) and wherein the connection between the connecting rod element (9) and the guide element (3) is at a distance from the center of gravity (S). [5] Crank mechanism (100) according to one of the preceding claims, characterized by that the connecting rod element (9) is connected to the guide element (3) in an articulated manner by means of connecting rod bearing flanges (8) and / or connecting rod axis flanges (24) arranged thereon and / or wherein the stationary guide means (2) is arranged with a base plate (20) on a side of the crankcase (21) facing away from the piston (13). [6] Crank mechanism (100) according to one of the preceding claims, characterized by that the guide element (3) is designed as a hollow cylinder in which a stationary guide pin (18) is received centrally for the lifting-movable guidance of the guide element (3) on the guide means (2). [7] Crank mechanism (100) according to one of the preceding claims, characterized by that the guide means (2) has a receiving cylinder (28) which is open in particular on both sides and which is constructed as a unit with the base plate (20) of the guide means (2) and in which a cylindrical guide element (3) is received. [8] Crank mechanism (100) according to one of the preceding claims, characterized by that the distance between the first articulation point (A1) and the second articulation point (A2) of one of the pistons (13) at its top dead center is equal to the distance between the first stroke axis (13.1) of the first piston (13) and the second stroke axis (13.2) of the second piston (13). [9] Crank mechanism (100) according to one of claims 5 to 8, characterized by a housing (1) which is formed at least from • a top cylinder plate (16) in which the cylinders (25) are formed, the crankcase (21), in which the crankshaft (5) is mounted so as to be freely rotatable in the axis of rotation (5.1) and • the base plate (20) of the guide means (2) arranged on the bottom side or a base plate (22) covering the base plate (20) on the underside. [10] Crank mechanism (100) according to one of the preceding claims, characterized by that the lifting axes (13.1, 13.2) and the lifting axis (H), in which the guide element (3) is guided in or on the guide means (2) in a lifting manner, run parallel to one another. [11] Device designed as a motor or compressor, characterized by that the device comprises a crank mechanism (100) according to one of the preceding claims and the crankshaft (5) of the crank mechanism forms an output shaft of an engine or a drive shaft of a compressor.

Images