Connecting rod, piston, crank drive device and reciprocating internal combustion engine

Abstract

The present invention relates to a connecting rod, particularly for an engine, including a head region, a central region (305), and a leg region. The head region has a first connection portion with a thickened section for connecting the piston to a connecting rod receiving area of ​​the piston for rotation about a pivot axis, the connecting rod receiving area having an undercut corresponding to the thickened section. The leg region has a second connection portion for receiving a crankshaft, and the head region is connected to the leg region through the central region. The present invention also relates to a piston, a crank drive, and an internal combustion engine.

Description

[Technical field]

[0001] The present invention relates to a connecting rod, in particular for a prime mover, having a head section, a middle section and a foot area. The head area is connected to a piston for rotation about a pivot axis. The head area of ​​the connecting rod is rotatably received in a connecting rod receiving part of the piston, which has an undercut corresponding to the wall thickness of the piston. The foot area of ​​the connecting rod has a crankshaft hole providing a second connection between the foot area and a crank pin of the crankshaft. The head region of the connecting rod is connected to the foot region by a middle region. The present invention also relates to a piston, in particular for a power machine, having an upper side, a lower side and a peripheral side, the peripheral side being configured to guide the piston in a cylinder bore and the upper side being designed to absorb the pressurizing force of a gas combustion event in a combustion chamber. On the underside of the piston there is a connecting rod receiving part with a connecting rod holder, with a pivot axis substantially perpendicular to the cylinder bore. The connecting rod holder includes an undercut arranged to receive the connecting rod head by sliding the connecting rod head laterally into the connecting rod receiver, so that the connecting rod can pivot relative to the piston about a pivot axis.Furthermore, the present invention relates in particular to an engine and / or a reciprocating internal combustion engine and a crank mechanism for a reciprocating internal combustion engine. [Background technology]

[0002] Known engines that function according to the reciprocating piston principle, for example diesel or gasoline engines, usually have a piston and a connecting rod pivotally attached to the piston. The piston and the head of the connecting rod each include a transverse bore. To pivotally connect the piston to the head of the connecting rod, a piston pin passes through the transverse bore of the piston and an aligned transverse bore through the head of the connecting rod. This arrangement means that in a reciprocating piston internal combustion engine, there is a significant reciprocating mass in each cylinder, including the piston and the piston pin. This has a negative effect on the efficiency of the engine and therefore prevents the reduction of pollutant emissions.

[0003] Pistons and connecting rods are known in which the so-called head of the connecting rod has a thickened section that can be hooked or pressed into a corresponding undercut in the piston so that the piston pin can be omitted. These designs are generally considered impractical due to assembly safety, lack of lubrication at the joint between the connecting rod and the piston, and manufacturing problems.

[0004] Such a piston / connecting rod connection cannot ensure, for example, cooling and lubrication of the joint between the connecting rod head and the piston by spray oil cooling, especially the piston crown cooling by spray oil starting in the vicinity of the crankshaft. For this reason, the advantages of a direct connection between the connecting rod and the piston (without the use of a piston pin) cannot be utilized without overheating and possible seizure of the swivel joint. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to improve upon the prior art. [Means for solving the problem]

[0006] This problem is solved by a connecting rod, in particular for prime movers, having a head region, a middle region and a foot region. The head region has a top section, a middle section and a bottom section. The head region is pivotally connected to the piston along a pivot axis (first connection). The head region is rotatably connected to the piston via a connecting rod receiving part of the piston, which has a rear section corresponding to the wall thickness. The foot region of the connecting rod has a second connection for receiving a crankshaft pin. The head area of ​​the connecting rod has a lubricant guide located above the middle region of the connecting rod and fluidically connecting the second connection part of the connecting rod to the first connection part of the connecting rod, whereby the lubricant applied to the second connection part in the region of the crankshaft crank pin is guided through the lubricant guide to the first connection part between the head of the connecting rod and the piston, and the lubricant is present for lubricating and / or cooling the first connection part.

[0007] With only a few modifications proposed in the present invention, such a device of the known connecting rod, i.e. the supply of a lubricant guide along the connecting rod, ensures that the first connection between the connecting rod and the piston is safely lubricated and / or cooled.

[0008] The following terms are explained in this context:

[0009] "Connecting rods" are used in so-called "crank drives" to connect reciprocating pistons in cylinders to a crankshaft. The connecting rod head is pivotally connected to the piston. The connecting rod leg area is rotatably connected to a crank pin journal on the crankshaft.

[0010] "Connection" refers to a mechanical connection, in particular a pivotal connection between a piston and a connecting rod, which in current designs of pistons and corresponding connecting rods are designed to mate and rotate about a pivot axis.

[0011] A "thickened section" of a piston is a region having a larger or wider cross section or diameter than adjacent regions. In particular, such thickened sections may serve, in conjunction with an undercut, to form a positive-locking tension- or compression-resistant connection between the piston and the connecting rod.

[0012] A "pivot axis" is, for example, the axis about which a connecting rod is rotatably or pivotally connected to a piston. This pivot axis corresponds, for example, to the axis of the piston pin in prior art designs.

[0013] A "piston" is a movable component which, together with a surrounding housing, in the case of a prime mover a "cylinder", forms an enclosed cavity, whereby the volume of the cavity varies with the position of the piston within the cylinder. Such a central component, in the present case specifically a reciprocating piston moving up and down within a cylinder, can be realised in a variety of designs.

[0014] "Undercut" refers to a design of a mounting or part of a mounting such that a component or an area or partial area in the direction of a force ensures that it does not pull out or allows the transmission of a force. Such an undercut may be used by the component that is mounted through the undercut to transmit a force.

[0015] A "connecting rod holder" at the bottom of the piston is used to tensilely and pivotally attach the connecting rod to the piston, whereby the piston together with the connecting rod is connected to a so-called crank drive, e.g. the connecting rod connecting the piston to the crankshaft. The pivotal connection of the piston to the connecting rod is established in such a way that the piston is non-clinically connected to the connecting rod at the connecting rod holder.

[0016] A "crankshaft" is a series of several crank pins on a common shaft having a central axis of rotation, whereby a respective connecting rod is connected to each crank pin, each connecting rod acting on a piston. The crankshaft can then be rotated by gas pressure on the pistons driven through the connecting rods. Such a crankshaft of a combustion engine has a central oil guide with an outlet for lubricating the crankshaft main bearings.

[0017] "Lubricant channel" refers to an exemplary channel-like or tubular design of the cross section of the connecting rod, which allows the lubricant to be safely guided, i.e., reliably transmitted from the starting area to the ending area. In particular, such a lubricant guide is, for example, a channel-shaped cavity or a channel in the connecting rod.

[0018] "Lubricants" are used for lubrication, in particular to reduce friction, wear and / or direct material contact. Furthermore, lubricants may be used for vibration damping and / or sealing or as corrosion protection. Lubricants may also act as coolants.

[0019] Such lubricants are, for example, lubricating greases, lubricating oils or, in the simplest case for a reciprocating piston internal combustion engine, oil contained in an oil pan or oil tank for lubricating the engine.

[0020] In particular, "lubrication" refers to the rheological properties of the lubricant, i.e., the reduction of friction, wear and / or direct material contact, whereas "cooling" refers to the removal of heat, particularly from the area of ​​the first connection. The heat removal process involves the transfer of heat to the lubricant and the corresponding removal of the lubricant from the area being cooled.

[0021] To make the connecting rod particularly simple, the lubricant guide extends in the form of a lubricant channel, which extends in particular along the central area of ​​the crankshaft. Such a lubricant channel can be, for example, a bore extending along the central area of ​​the connecting rod from the foot area to the connecting rod head. The lubricant channel is located close to the neutral plane in tension and compression, thereby minimizing weakening of the structure of the connecting rod.

[0022] In one embodiment, the supply of lubricant extends from a crankshaft bore associated with the second connection to the connecting rod head, in particular from an inner surface of the crankshaft bore to an outer surface of the connecting rod head.

[0023] According to this embodiment of the invention, for example, a large amount of pressurized oil already present inside the hollow crankshaft can be used to lubricate the crankshaft main bearing journals and the crankshaft crankpin journals. For this purpose, corresponding bores or holes can be provided in the crankpin journals and in corresponding bearing shells inserted in the crankshaft bores of the connecting rods. Pressurized engine oil flowing out of the crankshaft crankpin journals can be fed through the bearing shells of the crankshaft bores, through the lubricant channels of the connecting rods, up to the connecting rod heads, lubricating the pivotal connection between the connecting rod heads and the pistons. The transported oil performs both lubricating and cooling functions.

[0024] To enable a particularly reliable and simple production of the connecting rod, the lubricant channels are inserted into the connecting rod by spark erosion and / or deep hole drilling.

[0025] Electrical discharge machining, also called "spark erosion", can be used for high-precision material machining. For this purpose, the conductive workpiece to be machined is held in a dielectric liquid. The tool is brought into close proximity to the material and a voltage difference between the tool and the workpiece is used to generate sparks by localized discharges between the tool and the workpiece; these sparks remove material from the workpiece.

[0026] In particular, the channel-like eroded holes for the lubricant channels are created by a rod-shaped tool during the electrical discharge machining process.

[0027] In contrast, "deep hole drilling" can also be used as a specialized machining operation to create lubricant channels. Deep hole drilling is characterized by the fact that the drilling depth is many times greater than the diameter of the resulting channel.

[0028] In one embodiment, the lubricant channel includes a lubricant reservoir on the connecting rod head, particularly on the outer surface of the connecting rod head that attaches to the piston.

[0029] The presence of the lubricant reservoir allows for a corresponding retention of lubricant, i.e. an additional amount of available lubricant in the area of ​​the connecting rod head, which can also be used, for example, as a hydraulic cushion to prevent direct workpiece contact between the inner surface of the piston undercut and the outer surface of the connecting rod head.

[0030] The "lubricant reservoir" may be provided, for example, as a recess in the surface of the connecting rod head.

[0031] A valve arrangement may also be provided on the connecting rod head, which is used to control the lubricant introduced into the lubricant channel at the second connection in the area of ​​the crankshaft and regulates the flow of lubricant to the first connection by means of the pivot connection between the connecting rod head and the piston.

[0032] As a result, the valve device can be used to control the amount of lubricant delivered depending on the angle at which the connecting rod head pivots relative to the piston about the pivot axis, so that lubricant can only flow out of the reservoir, for example, when the connection between the piston and connecting rod is unloaded or only slightly loaded.

[0033] This further embodiment of the valve arrangement on the connecting rod may be implemented in a similar manner to the valve arrangement on the piston of a further aspect of the invention described below.

[0034] In a further aspect, the problem is solved by a piston, in particular for an engine, having an upper side, a lower side and a circumferential surface, the circumferential surface being designed to guide the piston in the cylinder bore and the upper side being designed to absorb the pressurizing force of the gas in the cylinder. The lower side has a connecting rod holder with an undercut having a cross section arranged essentially parallel to a pivot axis defining a pivot connection between the piston and the connecting rod head. The pivot axis is oriented transversely to the direction of the tension and compression forces exerted by the piston. The connecting rod holder is configured to be a tight slip fit for the corresponding connecting rod head, thereby making the pivot connection. The connecting rod head according to one of the previous embodiments includes a valve device for controlling the flow of lubricant through the lubricant channel to the first connection by pivoting the connecting rod head about the first connection pivot axis.

[0035] As with the possible arrangement of the valve device on the connecting rod, such a valve device serves to actively regulate the flow of lubricant depending on the angular position of the connecting rod relative to the piston. For example, the lubricant can only leak out at the time when the corresponding load between the piston and the connecting rod is particularly small or decreasing during one revolution of the crankshaft. Thus, for example, when the connection between the piston and the connecting rod is heavily loaded by the combustion process in the cylinder, the flow of lubricant through the valve device is blocked, so that the corresponding lubricant also remains in the lubricant reservoir, and then, for example, with the release of the load on the piston, the heated lubricant flows out of the first connection at a different angular position of the crankcase.

[0036] As already mentioned, it is immaterial whether the valve arrangement and / or the lubricant reservoir are located on the connecting rod head or inside the connecting rod holder of the piston.

[0037] In one embodiment, the valve device has a control pocket or several control pockets inserted into the inner surface of the undercut of the piston, the piston having a control pocket inserted into the cylinder bore and / or in the area of ​​the upper pressure point and / or in the area of ​​the lower pressure point of the piston in the cylinder bore and / or in the essentially linear contact surface, the flow of the lubricant is restricted or prevented depending on the angle of the connecting rod with respect to the axis of movement of the piston in the cylinder bore.

[0038] Such a control pocket or reservoir can be made using simple mechanical means, for example by milling processes, spark erosion processes or by casting a pocket during the casting of the connecting rod and / or piston. It is therefore a cheap addition. As already mentioned above, it is immaterial whether such a control pocket is located inside the connecting rod, i.e. inside the connecting rod head or inside the piston, or whether the two are combined. It is also conceivable that one part of the control pocket is located in the connecting rod and another part of the control pocket is located inside the piston.

[0039] The geometry of the control pockets is selected such that, for example, when the flow of the lubricant occurs, it is determined purely mechanically. For example, the lubricant may be allowed to flow out of the pockets only during the respective dead centers of the pistons (areas of movement where the pistons are relatively unloaded) in the cylinder bores and / or in the area of ​​the essentially linear arrangement of the connecting rods relative to the axis of movement of the pistons. Conversely, the flow of the lubricant may be restricted when the pistons are subjected to significant loads.

[0040] This allows for active and controlled lubrication and cooling of the first connection between the piston and the connecting rod, which improves heat dissipation, especially from the connecting rod. The combustion chamber is optimized and therefore the piston can be designed to store very little heat and therefore be very light. This weight reduction considerably increases the efficiency of the corresponding reciprocating piston combustion engine.

[0041] In this regard, the valve arrangement, in particular the control pocket, may be arranged and / or designed to restrict the flow of lubricant over an angle of ±20°, ±15°, ±10° and / or ±5° between the longitudinal axis of the connecting rod and the axis of movement of the piston in the cylinder bore.

[0042] This configuration defines a corresponding angle, in particular so that a full rotation of the crankshaft is used to control a corresponding control area of ​​the valve arrangement and / or control pocket according to the invention, the designation of the angle here referring to a full angle of 360° (one complete rotation of the crankshaft).

[0043] For a particularly effective cooling and lubrication of the piston, the connecting rod holder may have at least one lubricant channel extending away from the undercut or the inner cut surface of the undercut to the circumferential surface and / or one or more annular grooves arranged or formed in the circumferential surface. The one or more lubricant channels may be supplied via a lubricant supply channel formed in the connecting rod. The lubricant may be supplied in a manner suitable for cooling the piston in a particularly effective manner during operation of the internal combustion engine.

[0044] For example, two lubricant channels can be provided in the connecting rod holder of the piston so that the two channels are alternately supplied with lubricant through the lubricant channel of the connecting rod depending on the angular position of each lubricant channel relative to the pivoting connecting rod head. When one of these lubricant channels of the piston is supplied with lubricant through the lubricant channel of the connecting rod, the other lubricant channel is separated from the supply and vice versa. This ensures that the two lubricant channels are alternately supplied. In an intermediate state, where the connecting rod is essentially in a central position, lubricant is supplied to both lubricant channels of the piston. When the connecting rod is aligned approximately parallel to the cylinder bore, both lubricant channels of the connecting rod holder of the piston can be separated from the lubricant supply of the connecting rod head, so that the lubricant pressure builds up a pivot joint between the connecting rod head and the connecting rod holder of the piston. Thus, depending on the angular position of the connecting rod, the lubricant is either held under pressure in the piston at the connecting rod joint (during periods of high pistol loads) or delivered through lubricant channels in the piston to the piston periphery and / or ring groove (during periods of low piston loads). Thus, depending on the angular position of the connecting rod, the pressure ratio of the two lubricant ducts changes.

[0045] To ensure a particularly effective lubrication of the piston in the cylinder, the lubricant can pass through the piston up to its circumferential surface and / or its annular groove, where it can exit the piston from the circumferential surface or in the area of ​​the annular groove. The exiting lubricant can then be discharged in the direction of the crankshaft and / or the oil pan, where it can be cooled. From there, the lubricant can be returned to one or more lubricant ducts of the piston via an oil distribution scheme to the connecting rod and its lubricant supply. As a result, a lubricant circuit is realized from the leg area of ​​the connecting rod, through the lubricant channels of the connecting rod, up to and through the piston, and then returned to the sump. Due to the realization of such two lubricant channels of the piston, depending on the arrangement of the lubricant channels of the piston, there are two such circuits in which the lubricant flows in opposite directions from the piston to its circumferential surface and / or the annular ring groove.

[0046] For a particularly effective cooling and lubrication of the piston, the lubricant channel may have several outlets in the area of ​​the circumferential surface and / or the ring groove. The lubricant may be supplied through one or more inlets and several outlets.

[0047] Furthermore, for a particularly effective lubrication and cooling of the piston, the outlet or end of at least one lubricant channel can be inserted into a groove formed in the area of ​​the circumferential surface or the annular ring groove or into a recess in the side of the piston. Such a recess can be an outlet and can have a larger diameter or a larger surface area than the cross-sectional area of ​​the outlet or end of the lubricant channel. For example, the outlet can have an essentially rectangular shape. The lubricant can be collected in the recess and form a safety reservoir for supplying the lubricant to the circumferential surface of the piston. If necessary, several such recesses can be made in the circumferential surface of the piston, thereby providing lubrication in a particularly effective manner. At least one outlet or one end of the lubricant channel must be open in the area to be lubricated.

[0048] Furthermore, for a particularly effective cooling and lubrication of the piston, at least one lubricant channel may open into at least one buffer chamber having a cross-sectional area larger than the lubricant channel. Such a section or buffer chamber may be used as a safety reservoir to collect a suitable amount of lubricant to ensure a sufficient supply. This ensures a more reliable supply of lubricant through the lubricant channel and thus a reliable cooling and lubrication at the desired locations inside and outside the piston.

[0049] In particular, the at least one buffer space may be essentially spherical in shape, or the at least one buffer space may be elongated and / or curved in the region of one or more annular grooves disposed or formed in the circumferential surface of the piston. The size and location of the desired buffer space must take into account other spaces and design considerations in that region of the piston as a whole.

[0050] For a particularly effective cooling and lubrication of the piston, at least one lubricant channel may also have a branch with a branch channel for guiding the lubricant in the direction of the area adjacent to the top of the piston. Such a branch allows for a further distribution of the lubricant in the piston. Thus, the lubricant may be directed towards the top of the piston, which requires more cooling by the combustion in the combustion chamber adjacent to the top of the piston. The piston is usually exposed to particularly high temperatures in the adjacent combustion chamber. The branch channel and therefore the guide for the lubricant inside the piston may pass past the top of the piston without being connected to the combustion chamber top side.

[0051] Rather, the branch channel may extend past the area of ​​the top of the piston, to the area of ​​the undercut, to the inner surface of the undercut, to the underside of the piston, or with an outlet back to another area of ​​the piston. By designing the branch channel in this way, the lubricant delivered through the hotter part of the piston is discharged to the area below or below the piston. From there, the lubricant can return in the direction of the crankshaft and the lower end of the engine. The lubricant can then be recycled. The lubricant is returned through the lubricant channel of the connecting rod to the lubricant channel of the piston and then to the branch channel.

[0052] In the area adjacent to the top of the piston, a buffer chamber for the lubricant, connected to the branch channel, can be formed to ensure a particularly effective cooling of the piston in this area. This buffer chamber can be designed as an extension or bulge of the branch channel.

[0053] Alternatively or additionally, the junction between the lubricant channels can be an essentially spherical buffer space. In practice, it has been shown that this can ensure a particularly reliable guiding of the lubricant, for example without the formation of bubbles in the lubricant.

[0054] In a further aspect, the present invention applies to a crank mechanism, in particular for a prime mover and / or a reciprocating piston internal combustion engine, having a piston, a connecting rod and a crankshaft, the piston being designed according to one of the aforementioned embodiments and / or the connecting rod being designed according to one of the aforementioned embodiments.

[0055] Such a crank drive may be used, for example, as a pre-mounted assembly to prepare a highly efficient reciprocating piston internal combustion engine.

[0056] In a further aspect, the present invention may be applied to a reciprocating piston internal combustion engine, in particular a diesel engine or a spark ignition engine, having a piston according to one of the aforementioned embodiments, a connecting rod according to one of the aforementioned embodiments and / or a crank mechanism as previously described.

[0057] In this context, a "diesel engine" refers to an internal combustion engine that operates by compression ignition, whereas a "petrol engine" uses spark ignition, for example by an electric spark. Mixed forms are also possible.

[0058] The present invention is explained in further detail below with reference to the included drawing figures. [Brief description of the drawings]

[0059] [Figure 1] FIG. 2 is a perspective view including hidden lines showing the crank mechanism including the piston and the connecting rod. [Figure 2a] FIG. 2 is a side view of a piston from the assembly of FIG. 1. [Figure 2b] FIG. 2 is a bottom view of a piston from the assembly of FIG. 1. [Figure 2c] FIG. 2 is a side cross-sectional view of a piston from the assembly of FIG. 1. [Figure 2d] FIG. 2 is a bottom view of a piston from the assembly of FIG. 1 with cross-section callouts for FIGS. 4 and 6. [Figure 3a] FIG. 2 is a side view showing a connecting rod from the assembly of FIG. 1; [Figure 3b] FIG. 2 is a perspective view showing a connecting rod from the assembly of FIG. 1; [Figure 4] FIG. 2 is a perspective cutaway view showing the internal details of an embodiment of a piston of the present invention. [Diagram 5] FIG. 5 is a perspective view of the piston of FIG. [Figure 6] FIG. 2 is a perspective cutaway view showing the internal details of an embodiment of a piston of the present invention. [Figure 7]1 is a side view, with partial cross-section, illustrating an embodiment of a crank drive made in accordance with the present invention; [Figure 8] 1 is a perspective view, partially cut away, illustrating an internal combustion engine that utilizes a crank assembly provided by the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] As shown in FIG. 1, the crank unit 101 comprises a piston 201 and a connecting rod 301. The crank unit 101 is part of a diesel engine (not shown), whereby a corresponding diesel engine has, for example, four, six, eight crank units or even three crank units, whereby each of the pistons 201 is received in a corresponding cylinder so as to be movable along a movement axis 281. The connecting rod 301 is mounted around the crankshaft 185 on a respective crank pin of the crankshaft corresponding to the number of cylinders. The diesel engine is designed, for example, as an in-line 4-cylinder, in-line 6-cylinder or V8 engine. In any case, this is a diesel engine with high-pressure injection for the diesel fuel and a turbocharger and / or supercharger, which results in a high combustion temperature in the respective cylinder. Naturally, other designs with a corresponding number of crank units 101 are also possible. The pistons 101 are made from an aluminum alloy.

[0061] Each connecting rod 301 is forged from steel and then machined to finished condition. The pivot 183 defines the pivot connection between the piston and the connecting rod. During a complete rotation of the crankshaft (not shown), the crank pin, centered on the crankshaft 185, is guided in a circular motion and the piston 201 moves up and down in the cylinder by the connecting rod 301, thus executing a complete rotation of the crankshaft. The gas pressure generated on the upper side 203 of the piston 201 by the combustion of the injected diesel, for example, drives the piston 201 so that the engine as a whole operates according to the diesel principle. Ignition of the injected diesel fuel is achieved by compressing the intake air in the cylinder. The compression temperature exceeds 700° C. and the resulting combustion temperature exceeds 1,200° C. The piston 201 is exposed to high heat and suitable cooling is a design goal in any internal combustion engine.

[0062] In addition to the upper side (crown) 203, which is directed towards the combustion chamber in the cylinder, the piston 201 has a peripheral surface 205 and a lower surface 207 (see FIG. 2a). In the top surface, a combustion cavity 241 is provided, which is concentric with the axis of movement 281 (see FIG. 2c). A conical dome 243 extends upwards in the combustion cavity, which increases the surface area of ​​the combustion cavity of the piston 201.

[0063] The main components of the circumferential surface 205 form a piston skirt 219 which descends in the direction of the lower side 207 (see FIG. 2c). The piston skirt is cylindrical and has a thin wall. Starting from the upper side 203 (see FIG. 2a), the piston 201 has a narrow peripheral collar 221 with a distance of the upper side 203 to form a first annular ring groove 223. A piston ring for sealing against the cylinder is arranged in this first annular ring groove 223. Furthermore, in the direction of the lower side 207, a second annular ring groove 225 and a third annular ring groove 227 are arranged, whereby in the annular groove 225 a piston ring is inserted as a sealing ring and in the annular groove 227 a piston ring in the function of an oil scraper ring is inserted (piston rings are not shown in either case). An additional bore 229 is arranged above the annular groove 227, which facilitates the drainage of the engine oil.

[0064] The peripheral collar 221 is known in the prior art for diesel engines as a so-called "firewall" and in these engines is designed in the prior art with a diameter significantly smaller than the circumferential surface 20 of the piston. However, the peripheral collar 221 of the embodiment of the invention in Figure 2a has a radius 282 which is identical to the radius 284 of the circumferential surface 205 within engineering tolerances. Thus, the piston 201 can be machined to its cylindrical shape in a single clamping operation and a single turning operation to a uniform diameter on a lathe.

[0065] The peripheral collar 221 can be designed in this configuration because the present invention provides additional cooling to limit thermal expansion. The collar 221 must be made with a reduced diameter because in the prior art it would be the primary cause of increased heating of the piston crown causing significant expansion in this area. The piston heat sink of the present invention eliminates this need.

[0066] At the underside 207, the piston 201 has a connecting rod holder 210 for engaging a connecting rod 301. The holder 210 is essentially contained in a formed undercut 211 (see FIG. 2c), which is concentric around the pivot axis 183 and is characterized by respective edges 217 at the ends of the material. To leave the undercut 211 accessible along the pivot axis 183 and to allow the undercut 211 to terminate on the inner surface 213 of the connecting rod holder, the piston skirt 219 has cutouts 220 on both sides along the pivot axis 183. This cutout 220 allows the connecting rod head 303 (see FIG. 3a) to slide laterally into the connecting rod holder and to pivotally engage the inner surface 213 (see FIG. 2a). Furthermore, the presence of cutout 220 allows for the insertion of a tool for fine machining of inner surface 213 .

[0067] As can be seen from the underside of the piston 201 (see also FIG. 2b), the piston 201 is not radially symmetrical. In addition to the direct technical volume of the piston 201, i.e. the volume for forming the connecting rod holder 210 together with the undercut 211, the volume of the piston skirt 219 as well as the corresponding volumes of other features vary. The piston 201 has an area of ​​thickened wall 231, 235. The piston also comprises a number of pockets 233. The thickened wall and the pockets are arranged symmetrically with respect to the pivot axis 183. The corresponding volumes of the thickened part 231, the pocket 233 and the thickened part 235 are selected so that both the pocket 233 and the thickened part 235 can be such cut surfaces formed along the intersecting planes through the movement axis 281, i.e. for example the cut surfaces 271, 273 or 275 (see also FIG. 2d), each having the same cross-sectional area with respect to the cut surface 271, for example within a tolerance of 2% with respect to the smallest one in the respective compared intersecting plane. This geometric design ensures that the thermal expansion behavior of the piston 201 is almost identical or even identical at different polar positions around the movement axis 281. For this purpose, material is added to the thickened part 231, material is removed from the pocket 233 and material is added to the thickened part 235. In this way, the volumes technically required for example for the pickup 210, for example added at the respective cut surfaces, are balanced accordingly. Similarly, for example, each thickened portion 235 is provided to at least partially offset the reduction in cross-sectional area over the area of ​​cutout 220 and the missing material in piston skirt 219. Similarly, other components are compensated for by removing or adding corresponding volumes of material to piston 201 to keep the piston balanced.

[0068] Annular retaining ring grooves 215 are provided in the inner surface 213 of the undercut 211 symmetrically about the axis of movement 281 on either side along the pivot axis 183 (see FIG. 2b), and are formed as partial annular grooves 215 due to the shape of the undercut 211. Each annular retaining ring groove 215 has a cross-section that extends from a diameter 216 of the inner surface 213 to a diameter 218 of the inner surface 213 (see FIG. 2c).

[0069] The connecting rod 301 (see FIG. 3a) has a connecting rod head 303, an intermediate region 305 and a crankshaft connection 307. The connecting rod head is designed as a bulge with a cylindrical outer surface 311. The outer surface 311 is machined for a close sliding and pivoting fit in the inner surface 213 of the piston. Furthermore, a chamfer 312 is arranged in the end region of the head 303 in the direction of the pivot axis 183. Thus, the connecting rod head 303 can be inserted laterally into the piston along the pivot axis 183 such that a pivot joint is made between the connecting rod and the piston around the pivot axis 183.

[0070] The intermediate region 305 connects the connecting rod head 303 with the crankshaft connection 307 and has a neutral plane between the connecting rod head 303 and the crankshaft connection 307. The intermediate region 305 also has recesses 306 on both sides, so that, overall, the rigid cross section of the intermediate region 305 is formed as a double T-beam. Furthermore, webs 315 with recesses 316 formed oppositely with respect to the intermediate region 305 are arranged so that the intermediate region and the crankshaft connection 307 are rigid and yet as light as possible.

[0071] Approximately half of the crankshaft connection 307 consists of a portion of the connecting rod 301. The other half consists of the connecting rod cap 308, the two components being concentrically disposed about the crankshaft axis 185. A bearing shell 321 is provided on the inner surface of the crankshaft bore 309 to create a low friction, wear resistant and quickly operable connection to the crankshaft. The bearing shell is provided with features that rotationally fix its position relative to the connecting rod 301 and rod cap 308.

[0072] Furthermore, the connecting rod 301 has a valve groove 341 of smaller diameter on the outer surface area 311 of the connecting rod head 303 (see FIG. 3b). The valve groove 341 is connected to an outlet opening 343 (see FIG. 3a). The outlet opening 343 is part of an oil channel 345, which is located between the outlet opening 343 and an inlet opening 347 arranged inside the crankshaft bore 309. The oil channel 345 is located along the neutral plane of the intermediate region 305 (a plane in which the metal particles are neither compressed nor stretched in normal operation), so that the intermediate region 305 is only weakened as little as possible by the oil channel 345, especially against bending.

[0073] To fit the connecting rod 301 to the piston 201, the connecting rod head 303 is pressed laterally along the pivot axis 183 into the piston undercut 211 (see FIG. 2a). In the annular retaining ring groove 215, a resilient retaining ring (not shown) with a round wire cross section is inserted such that a portion of the retaining ring is inserted into the cross section of the undercut 211 formed by the inner surface 213. This retaining ring is then pressed back into the annular groove 215 by the chamfer 312 on the connecting rod head 303, whereby the cross section of the retaining ring is selected so that it can be positioned completely between the diameters 216 and 218.

[0074] Thus, the chamfer 312 facilitates insertion of the connecting rod head 303 into the piston 201. The use of a retaining ring in the retaining ring groove 215 secures the connecting rod head 303 against unintentional removal from the piston along the pivot axis 183.

[0075] The function of the crank unit 101 with regard to lubrication of the connection between the connecting rod head and the piston 201 at the undercut 211 is explained as follows.

[0076] Inside the crankshaft, not shown, there are oil channels that extend to lubricate the corresponding support points of the crankshaft. Crankshaft oil outlet holes are provided at the support points. The crankshaft also has corresponding outlet holes for pressurized engine oil on the crankpin journals that receive the respective connecting rods 301 around the crankshaft 185. The engine oil is then fed into a peripheral annular groove on the crankshaft and flows through the inlet opening 347 (see FIG. 3a) in the oil channel 345 to the outlet opening 343. At the outlet opening 343 and the valve groove 341 an oil reservoir is created in which the pressurized engine oil is collected for lubrication of the pivoting interface between the cylindrical surface 311 (on the connecting rod) and the cylindrical inner surface 213 (on the piston).

[0077] Furthermore, the valve groove 341 is used to control the oil flow depending on the position of the crankshaft and the resulting position of the connecting rod 301 relative to the piston 201. When the piston 201 reaches top or bottom dead center, the connecting rod 301 is essentially vertical in the cylinder bore along the axis of movement 281. In that state, the valve groove 341 is completely sealed against the inner surface 213 of the undercut 211 so that oil cannot escape through the valve groove 341. Reliable lubrication and ideal lubrication are then guaranteed, for example when ignition of the fuel in the cylinder occurs, and heat transfer between the piston 201 and the connecting rod 301 is ensured. Similarly, the oil cushion of the oil reservoir also prevents direct material contact.

[0078] During the power stroke, the piston 201 is heated by the combustion gases and pushed downwards. First, the crankshaft pivots about 90° from TDC and the connecting rod 301 pivots relative to the piston. The valve groove 341 is now dimensioned such that a portion of the valve groove 341 is free at the edge 217 of the undercut 211 (see FIG. 2c). At this time, oil supplied through the oil channel 345 under engine pressure is released from the open portion of the valve groove 341. This oil is also heated and its release transfers heat away from the connecting rod / piston connection. In this condition, the connection between the connecting rod head 303 and the undercut 211 is relatively lightly loaded, so that the engine oil outflow can now be used effectively, even though this means that less oil is available for lubrication.

[0079] Then, when the crankshaft approaches bottom dead center (180° from TDC), the undercut 211 closes the valve groove 341. At this time, the inertia of the crankshaft can therefore act. Further crankshaft rotation starts the exhaust stroke, which starts with maximum oil pressure in the closed valve groove 341. At this point, there is also further heat transfer to the engine oil. Then, at a crankshaft position of 270°, the valve groove 341 of the valve is opened by a part of the valve groove 341 pivoting past the edge 217, so that oil pressure is again used to transfer heat from the engine oil. Then, up to a crankshaft position of 360° (0° or the full angle corresponding to TDC), the valve groove 341 is again closed by the edge 217, so that maximum oil pressure is again present in the connection at top dead center and a new availability of heat transfer for oil dissipation is reached. This cycle is of course repeated with each revolution of the crankshaft, whereby the result is sufficient lubrication of the movement about the pivot 183 and optimized heat dissipation from the connecting rod 301 and piston 201.

[0080] 4 to 6 show a further embodiment example of a piston 201 according to the invention in a perspective side view from different angles, the piston 201 shown being partially cut away to reveal internal details for a better illustration. The cross-section of the piston 201 required for this is made on the one hand in the direction of the pivot axis 183 and on the other hand perpendicular to this direction.

[0081] The piston 201 shown in Figures 4-6 has essentially the same external structure as the piston 201 shown in Figures 1-2d, so that the advantages described for the piston 201 above also apply to the piston 201 described below. However, the piston 201 shown in Figures 4-6 differs from the piston 201 shown in Figures 1-2d in terms of its "internal mechanism".

[0082] In particular, the connecting rod holder 210 has two lubricant channels that extend from the inner surface 213 of the undercut 211 to the circumferential surface 205 and the annular ring grooves 223, 225, 227 arranged in the circumferential surface 205. In Fig. 4 it is particularly easy to see that the lubricant channels 290 extend in opposite directions, whereby one lubricant channel 290 is recognizable as cut out, while the other lubricant channel 290 is recognizable only by its inlet in the inner surface 213.

[0083] The lubricant duct 290 first extends to a substantially spherical buffer chamber 291. There, a branch 292 is formed which leads to a branch channel 293. Through the branch channel 293, the lubricant is fed to a further buffer chamber 291 below the area of ​​a conical dome 294. Via this further buffer space 291, a lubricant reservoir is provided which helps to cool this area 294.

[0084] After passing a further buffer space 291 adjacent to the dome 294, the branch channel 293 continues in the rear buffer space 291, in the direction of the cutting edge 211 or towards the underside 207 of the piston 201. The branch channel 293 ends in an area 296 of the undercut 211, an area 297 of the undercut 211 and an outlet 295 in the area 297 of the undercut 211, in which the head 303 of the connecting rod 301 is pivotally mounted. Thus, the lubricant can flow out of the branch channel 293 next to the connecting rod which is coupled to the piston 201.

[0085] The lubricant not fed from the essentially spherical buffer chamber 291 to the branch channel 293 is further fed to an external buffer chamber 291, which extends in the area of ​​the annular ring grooves 223, 225, 227 near the outer periphery of the piston. This external buffer chamber 291 has a curved shape substantially adapted to the outer periphery 205 of the piston 201. The buffer chamber 291 extends essentially along half the circumference of the piston 201 and is therefore shaped into a quasi-half ring. Due to the fact that two lubricant ducts 290 are realised in this example embodiment, in this embodiment where a plurality of spaces 291 is realised, two such outwardly curved buffer chambers 291 are also provided, whereby each lubricant channel 290 leads to such a buffer space 291.

[0086] The lubricant is supplied from the external buffer chamber 291 to the peripheral surface 205 and to the annular ring grooves 223, 225, 227, whereby lubricant outlets 299 are located in the peripheral surface 205 (see FIG. 5 ). The outlets 299 are partly realized in recesses 298 in the peripheral surface 205. Such recesses 298 serve as lubricant reservoirs. In the embodiment shown here, a total of four recesses 298 are realized in the peripheral surface 205, and an outlet 299 is realized in each recess 298 such that reliable filling of the recesses 298 with lubricant is guaranteed.

[0087] In the embodiment shown here, one branch channel 293 is realised from each of the two lubricant channels 290. Both branch channels 293 meet or intersect with each other in a further buffer chamber 291 in the area of ​​the dome 294. Both branch ducts 293 share the same buffer space 291 near the area of ​​the dome 294. So this further buffer chamber 291 has a total of two inlets and two outlets, one for each branch channel 293 and one for each of the other branch channels 293.

[0088] In a simplified embodiment of the piston 201, it is also possible to continue the lubricant channel 290 directly in the sense of a branching channel 293. In such an embodiment, the lubricant is not guided to the peripheral surface 205 of the piston 201, but instead is supplied directly to the piston 201 and is simply guided in a circle without branching from the undercut 211 or the inner surface 213 of the undercut 211 again to the undercut 211, the inner surface 213, the underside 207 of the piston 201 or the outlet 295 in the region 296 of the undercut 211. This creates a cycle or circular guidance of the lubricant in the piston 201 or the connecting rod holder 210.

[0089] 7 shows a partial cross-sectional side view of an example embodiment of a crank mechanism according to the invention, which comprises a piston 201 according to one of the above-mentioned example embodiments and a corresponding connecting rod 301 with a lubricant guide located inside the piston 201 according to one of the above-mentioned example embodiments, i.e. a crank unit 101, and a crankshaft 401. The connecting rod 301 is coupled to the crankshaft 401 in a conventional manner. The piston 201 is arranged in a cylinder arrangement 501 along which it is movable along an axis 281.

[0090] 8 shows a detailed perspective partial cutaway view of an example embodiment of a reciprocating piston combustion engine 601, with a cylinder arrangement 501 having four cylinders forming a cylinder bank of an in-line four-cylinder engine, as well as a piston 201 and a connecting rod 301 according to one of the above embodiments. In each case, the piston 201 and the connecting rod 301 form a crank unit 101. The connecting rod 301 is connected to a crankshaft 401.

[0091] In the design example shown in Figures 7 and 8, the "inner workings" of the piston 201 and connecting rod 301 are not shown for clarity.

[0092] In this connection, it is noted that in all embodiments, the geometric design of the piston 201, as explained above, also optimizes heat dissipation. The central connection of the connecting rod 301 to the receiving part 210 of the piston 201 allows for better heat transfer, so that the "grate bar" known from the prior art can also be dispensed with. Together with the simple geometry and uniform roundness of the piston 201, this makes it possible to result in a diesel engine that is easy to manufacture and yet very efficient.

[0093] As a result, the diesel engine can be operated at high combustion temperatures and therefore with efficient combustion with reduced emissions, and the geometry of the piston 201, the compact design and the centralized combustion cavity allow the engine to operate at high combustion temperatures. The excess heat is dissipated to the connecting rod 301 by the controlled oil flow through the rest of the engine. The circulating oil provides good thermal management. Overall, therefore, the combination of the piston 201 and connecting rod 301 according to the invention has reduced reciprocating mass. It should be noted that although this type of piston 201 and connecting rod 301 has been shown in this embodiment with respect to a diesel engine with high pressure injection and turbocharger, the same device is suitable for other types of engines and machines, including gasoline engines and compressors. [Explanation of symbols]

[0094] 101 Crank unit 183 Swivel Axis 185 Crankshaft (crankpin shaft) 201 Piston 203 Top side (piston crown) 205 Peripheral surface 207 Lower side (bottom side) 210 Connecting rod holder 211 Undercut 213 Inside 215 Retaining ring groove 216 diameter 217 Edge 218 diameter 219 Piston Skirt 220 Cutout 221 Outer circumference color (surrounding color) 223 Ring groove (top compression ring groove) 225 Ring Groove (Second Compression Ring Groove) 227 Ring groove (oil control ring groove) 229 Drill Hole 231 Thick part 233 Pocket 235 Thick part 241 Combustion Cavity 243 Conical Dome 261 Width 271 Cut surface 273 Cut surface 275 Cut surface 281 Moving axis 282 Radius 284 Radius 290 Lubricant Channel 291 Buffer Chamber 292 Branch 293 Branch Channel 294 Conical Dome 295 Exit 296 Area 297 Area 298 Recess 299 Exit 301 Connecting rod 303 Connecting rod head 305 Mid-range 306 Depth (recess) 307 Crankshaft connection 308 Connecting Rod Cap 309 Crankshaft hole 311 Exterior 312 Chamfered part 315 Bar (Web) 316 Recess 321 Bearing shell 341 Valve Groove 343 Exit opening 345 Oil Channel 347 Entrance opening 401 Crankshaft 501 Cylinder device 601 Reciprocating internal combustion engine

Claims

1. A connecting rod (301), particularly for a prime mover, having a head region (303), a middle region (305) and a leg region (307), wherein the head region (303) has a pivotal first connection with a connecting rod receiving portion (210) of a piston (201), the pivotal first connection corresponding to the head region (303) engaging an undercut (211) of the connecting rod receiving portion (210) of the piston (201), and the leg region (307) has a second connection for receiving a crankshaft, and the head region (303) has lubricant guides (343, 345, 347) in the connecting rod (301) connected to the leg region (307) via the intermediate region (305), whereby lubricant introduced into the lubricant guides (343, 345, 347) at the second connection part in the region of the crankshaft is guided to the first connection part through the lubricant guides (343, 345, 347), and the lubricant is available for lubricating and / or cooling the first connection part.

2. 2. A connecting rod (301) according to claim 1, characterized in that the lubricant guides (343, 345, 347) have lubricant channels (345), which extend in particular along the intermediate region (305).

3. 2. A connecting rod (301) according to claim 1, characterized in that the lubricant guide (343, 345, 347) of the crankshaft bore (307) associated with the second connection portion transports lubricant to the head region (303), in particular from an inner surface of the crankshaft bore (307) to the head region (303).

4. 2. A connecting rod (301) according to claim 1, characterized in that the lubricant guides (343, 345, 347) are introduced into the connecting rod (301) by spark erosion and / or deep hole drilling.

5. 2. A connecting rod (301) according to claim 1, characterized in that the lubricant guide (343, 345, 347) of the head region (303) has a lubricant reservoir (341), the lubricant reservoir (341) being integrated in particular into an outer surface (311) of the head region (303) and / or being associated with the connecting rod receiving portion (210).

6. A piston (201), in particular for an engine, having an upper side (203), a lower side (207) and a circumferential surface (205), the circumferential surface (205) being designed to guide the piston (201) in a cylinder bore, and the upper side (203) being designed to absorb the pressurization force of gases in a cylinder, the lower side (207) having a connecting rod receiving portion (210) with an undercut (211) having a cross section arranged substantially parallel to a pivot axis (183) in the direction of tension and pressure, and the connecting rod receiving portion (210) corresponding to the connecting rod receiving portion (210). Item 1. A piston (201) designed to receive the connecting rod (301) according to item 1 in a mating manner and pivotably about the pivot axis (183), wherein the connecting rod receiving portion (210) has a valve device for controlling lubricant, and the lubricant is introduced into the lubricant guide (343, 345, 347) at the second connection portion in the region of the crankshaft, and is guided to the first connection portion through the valve device by pivoting the connecting rod head (303) about the pivot axis (183).

7. 7. The piston (201) according to claim 6, characterized in that the valve device comprises a control pocket or a plurality of control pockets formed on the inner surface (213) of the undercut (211), by which the flow of lubricant is restricted or prevented, in particular in the region of top dead center and / or bottom dead center of the piston (201) in the cylinder bore and / or in a substantially linear arrangement of the connecting rod (301) relative to the axis of movement (281) of the piston (201) in the cylinder bore.

8. 7. The piston (201) according to claim 6, characterized in that the valve device, in particular the control disc, is arranged and / or designed to restrict the flow of the lubricant over an angle of ±20°, ±15°, ±10° and / or ±5° between the longitudinal axis of the connecting rod (301) and the axis of movement (281) of the piston (201) in the cylinder bore.

9. 7. The piston (201) according to claim 6, characterized in that the connecting rod receiving portion (210) has at least one lubricant channel (290) extending from the undercut (211) or an inner surface (213) of the undercut (211) to the circumferential surface (205) and / or to one or more annular ring grooves (223, 225, 227) arranged or formed in the circumferential surface (205).

10. 10. The piston (201) according to claim 9, characterized in that one end of the at least one lubricant channel (290) opens into a recess (298) formed in the region of the circumferential surface (205) or the annular groove (223, 225, 227).

11. 10. The piston (201) according to claim 9, characterized in that in the at least one lubricant channel (290), at least one section has a diameter larger than the diameter of the at least one lubricant channel (290) or at least one buffer chamber (291) for the lubricant is formed.

12. 12. The piston (201) according to claim 11, characterized in that the at least one buffer chamber (291) is essentially spherical in shape or that the at least one buffer chamber (291) is elongated and / or curved in the region of one or more annular grooves (223, 225, 227) arranged or formed in the peripheral surface (205).

13. the at least one lubricant channel (290) has a branch (292) with a branch channel (293) for directing lubricant toward a region (294) adjacent the upper side (203) of the piston (201); said branches (292) may be formed in a buffer space (291)—preferably of essentially spherical shape; and / or 10. The piston (201) according to claim 9, characterized in that, after passing through the region (294), the branch channel (293) extends to the undercut (211), to the inner surface (213) of the undercut (211), to the underside (207) of the piston (201), or to a region (296) of the undercut (211) or of the connecting rod receiving portion (210) with an outlet (295), the outlet (295) being formed next to a region (297) of the undercut (211) in which a head (303) of a connecting rod (301) is located when the piston (201) is in an operating state coupled to the piston (201).

14. A crank mechanism (101), in particular for a prime mover and / or a reciprocating piston internal combustion engine (601), comprising a piston (201), a connecting rod (301) and a crankshaft (401), characterized in that the piston (201) according to any one of claims 6 to 13 or A crank mechanism (101) characterized by a connecting rod (301) according to any one of claims 1 to 5.

15. A piston (201) according to any one of claims 6 to 13 or A reciprocating piston internal combustion engine (601), in particular a diesel or gasoline engine, comprising a crank mechanism (101) according to a connecting rod (301) according to any one of claims 1 to 5.

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