DE102015109924A1 - Piston for a connecting rod and connecting rod - Google Patents

Abstract

The invention relates to a piston (14), in particular for a connecting rod (100) with an eccentric adjustment device for adjusting an effective connecting rod length, which is displaceably guided in a hydraulic chamber (16) and in which a support rod (18) of the eccentric adjusting device is mounted is.
According to the invention, the piston (14) is provided split and has a base body (22) and an annular body (24) mounted thereon, wherein a sealing ring (26) can be fastened on the piston by means of the annular body (24).
The invention further relates to a connecting rod (100) with such a piston (14) and an internal combustion engine with such a connecting rod (100).

Description

Technical area

The invention relates to a piston, in particular for a connecting rod with an eccentric adjusting device, in particular for an internal combustion engine with variable compression and such a connecting rod with such a piston and an internal combustion engine.

State of the art

In internal combustion engines, a high compression ratio has a positive effect on the efficiency of the internal combustion engine. Under compression ratio is generally understood the ratio of the entire cylinder space before compression to the remaining cylinder space after compression. In internal combustion engines with spark ignition, in particular gasoline engines, which have a fixed compression ratio, however, the compression ratio may only be selected so high that a so-called "knocking" of the internal combustion engine is avoided at full load operation. However, for the much more frequently occurring partial load range of the internal combustion engine, that is to say with low cylinder filling, the compression ratio could be selected with higher values without "knocking" occurring. The important part load range of an internal combustion engine can be improved if the compression ratio is variably adjustable. For the adjustment of the compression ratio, for example, systems with variable connecting rod length are known.

From the DE 10 2005 055 199 A1 is a connecting rod with an eccentric adjustment known. Support rods of the eccentric adjusting device are each firmly connected to a piston displaceably guided in a hydraulic chamber. The piston has on its outside a flexible sealant. The eccentric adjusting device is brought into operative connection with one or two reciprocating pistons. In order to allow a damped movement in both directions of rotation, there are two closable spaces in which the respective hydraulic volume is arranged.

The eccentric is in communication with a first and a second lever for rotating the eccentric, wherein the first lever with a first damping volume and the second lever are coupled to a second damping volume. The damping volumes comprise lifting cylinders, which form the majority of the damping volumes. Damping volumes also include conduits as well as other elements. An attenuation volume is also formed by the fluid present in a cylinder or cylinder-like space element.

A connection between the eccentric and a reciprocating piston of a lifting cylinder is produced by means of a lever connected to the eccentric and a push rod. Two chambers are created via two inserted reciprocating pistons, whereby a reciprocating piston is used for damping for each direction of rotation. The rooms used are connected via a check valve with a pressure oil circuit. This is arranged in such a way that oil can always flow into the room. Thus, with the help of valves, which are arranged in the connecting rod, one room is connected to the crankcase, while the other room is closed by a valve.

Disclosure of the invention

An object of the invention is to provide a piston, in particular for a connecting rod with an eccentric adjusting device for adjusting an effective connecting rod length, which is easy to assemble and at the same time has a good wear behavior.

Another object is to provide a connecting rod for a variable compression internal combustion engine with such a piston.

The above objects are achieved with the features of the independent claims.

Favorable embodiments and advantages of the invention will become apparent from the other claims, the description and the drawings.

It is proposed a piston, in particular for a connecting rod with an eccentric adjusting device for adjusting an effective connecting rod length, which is guided displaceably in a hydraulic chamber and in which a support rod of the eccentric adjusting device is mounted.

According to the invention, the piston is provided split and has a base body and an annular body mounted thereon, wherein by means of the annular body a sealing ring on the piston can be fastened.

The piston, which is guided displaceably in the hydraulic chamber, is connected to the support rod, which actuates the eccentric adjusting device. For this purpose, the piston with the support rod is connected so that the support rod can not lift off from the piston by the movement of the piston and thus always exists an operative connection between the two components. The piston is tightly guided in the hydraulic chamber to have as little leakage of the hydraulic fluid and thus losses of the eccentric adjusting device. For this purpose, the sealing ring is provided, which is expediently arranged on the outer circumference of the piston and the gap seals between the circumference of the piston and an inner wall of the hydraulic chamber. The sealing ring should maintain its position on the circumference of the piston during the lifting movement. At the same time friction losses during the movement of the piston should be as low as possible. The sealing ring should therefore also experience a lubricating effect of the hydraulic fluid. To obtain such a favorable arrangement of the sealing ring on the outer surface of the piston, the piston is advantageously divided into at least two parts. A base body serves to support the support rod and to receive the annular body, which can be pushed or pressed onto this base body, for example. This ring body also serves to attach the sealing ring on the piston, for example, by the sealing ring is pushed onto a portion region of the annular body and the ring body is attached to the sealing ring on the body. Conveniently, the sealing ring can be pressed by the ring body against the body, so that the sealing ring is thus fixed without play. Thus, the sealing ring can be mounted in a simple manner on the piston and is arranged at the same time captive. An advantage of this type of assembly of the sealing ring is that the sealing ring does not have to be expanded for assembly, but can be pushed in its desired shape on the annular body and this nominal shape also retains. This makes it possible to use even rigid sealing materials for sealing.

According to an advantageous embodiment, the sealing ring may be arranged on the annular body. Such an arrangement of the sealing ring on the ring body is favorable, since the sealing ring is pre-mounted on the ring body and can be stored together with the ring body and also mounted. This simplifies assembly. In addition, the risk that the sealing ring is damaged during assembly, thereby also reduced. Also, the sealing ring can be pre-centered so.

According to an advantageous embodiment of the annular body may be provided as a press ring, which can be pressed onto an annular shoulder of the body. The press fit is a very simple and flexible way to mount a body to another body while forming a firm and lasting connection. Such compounds are judged to be very reliable. In this respect, this type of assembly of the annular body on the base body, in particular on the annular shoulder of the base body is a very reliable mounting option, which is also favorable from a space engineering point of view.

According to an advantageous embodiment, the sealing ring may have a rectangular cross-section, whereby a good sealing effect can be achieved with a small gap between the piston outer surface and bore of the hydraulic chamber. Also, a rectangular cross section may form such a wide running surface of the seal on the sliding surface of the bore of the hydraulic chamber. As a result, a favorable wear behavior is achieved at the same time good sealing effect, which contributes to an overall efficient operation of the eccentric adjusting device.

According to an advantageous embodiment, the sealing ring may be arranged in a radially outer annular recess of the annular body and be held on the base body in the axial direction between the annular body and the base body after assembly of the annular body. As a result, a play-free arrangement of the sealing ring on the annular body can be achieved. The sealing ring can thus be held favorably between the base body and the annular body, so that the sealing ring remains in its position during operation of the piston. In addition, the wear of the sealing ring and the sliding surface of the hydraulic chamber can be made favorable. Tolerances can be kept so advantageous during assembly.

According to an advantageous alternative embodiment, the sealing ring may be arranged on the annular shoulder of the base body and be held on the base body in the axial direction between the annular body and the base body after assembly of the annular body. Even by such a direct arrangement of the sealing ring on the circumference of the body, a play-free arrangement of the sealing ring on the piston can be achieved. The sealing ring can thus be held favorably between the base body and the annular body, so that the sealing ring remains in its position during operation of the piston. In addition, the wear of the sealing ring and the sliding surface of the hydraulic chamber can be made favorable. Tolerances can be kept so advantageous during assembly.

According to an advantageous embodiment, the sealing ring may be formed of a non-elastic material. Such seals have an improved wear behavior and are not "activated" by the pressure and thus pressed apart. Ideally, the seal does not touch the bore of the hydraulic chamber and a lubricating film is formed between the seal and the bore.

Due to the wide bearing surface of the sealing ring on the bore of the hydraulic chamber a favorable sealing effect is achieved. As a result, a very efficient operation of the eccentric Versteillinrichtung can be achieved overall.

According to an advantageous embodiment, the sealing ring may be formed from gray cast iron material be. Cast iron material represents a very favorable variant of a sealing ring made of a non-elastic material. The material is inexpensive, can be processed well and has good running properties on the sliding surface of the bore. This makes it possible to realize a very favorable and efficient embodiment of a piston according to the invention.

According to an advantageous embodiment, a projection of an outer diameter of the sealing ring to an outer diameter of the base body and / or the annular body of at least 10 microns, preferably at least 15 microns, most preferably at least 20 microns be provided. Such a slight projection is sufficient to have a good sealing effect of the sealing ring when moving in the bore of the hydraulic chamber and to show a favorable wear behavior over the duration of the operation. The sealing ring also causes a corresponding deformation of the piston when the piston is loaded during operation due to the high pressure of the hydraulic fluid.

Advantageously, the sealing ring for the intended installation in the hydraulic chamber with radial clearance to a bore of the hydraulic chamber of a maximum of 100 .mu.m, preferably at most 80 .mu.m, most preferably a maximum of 50 microns may be provided. By such a mechanically decoupled arrangement of the piston with sealing ring in the bore of the hydraulic chamber, an operation of the piston under high hydraulic pressure designed as very efficient. As a result, the sealing ring can also participate in a corresponding deformation of the piston and / or the hydraulic bore when the piston is loaded during operation due to the high pressure of the hydraulic fluid.

According to an advantageous embodiment, the base body may be formed as a ball head receptacle for a arranged on the support rod ball head. By designed as a ball end part of the support rod, which is mounted in a corresponding ball-head receptacle of the body and thus the piston, a very large freedom of movement of the support rod is achieved relative to the piston, since the support rod can move over a large angular range. Such a ball joint is also very low friction, so that overall the frictional forces during operation of the eccentric adjustment can be kept low. Thereby, a very advantageous ball bearing can be provided, which is easy to assemble and is highly resilient and allows manufacturing tolerances.

According to an advantageous embodiment, a securing element may be provided which secures the ball head on its outer surface in the ball head receptacle against slipping out of the ball head receptacle, wherein the securing element is in particular formed with a radially inwardly projecting undercut. The fuse element is a very efficient way to prevent slipping out of the ball head from the ball head socket. It can be conveniently mounted after the insertion of the support rod with the ball head in the ball head receptacle of the body and also allows the support bar greatest freedom of movement over a large angular range.

According to an advantageous embodiment, the securing element may be formed as an at least partially deformable wall of the base body. In this way, the securing element can be an integral part of the body and thereby captively connected thereto. Also can be prepared by deformation of the wall of the body, the fuse element in a very simple and inexpensive way with the help of a tool by forming appropriate. The wall can be applied at least partially by forming in the radial direction inwardly to an outer contour of the ball head and thus form the securing element. Thus, the support rod is connected in a simple and captive manner with the body.

According to an advantageous alternative embodiment, the securing element may be formed as a securing ring. A circlip is a simple and inexpensive way to implement the backup of the support rod against slipping out of the ball head receptacle of the body. Such a circlip represents a simple component. Also, such a circlip can be solved if necessary to replace the piston and / or support rod again, which gives the possibility of repair or replacement. The mounting of the locking ring is very easy and quick to perform. The locking ring can be easily inserted into the ball head receptacle. The securing ring may be formed symmetrically, in particular along its longitudinal axis, so that a mounting can be carried out confusion. Alternatively, the embodiment may also be asymmetrical. Advantageously, the ball head is pivotable in the ball head receptacle and at the same time axially pulled out only with high pull-out force from the ball head receptacle.

According to an advantageous embodiment, the ball head receptacle may have an undercut at its open end, which axially secures the securing ring in the ball head receptacle. Such an undercut is easily produced in terms of production and offers a particularly high level of safety against sliding out of the securing ring and thus of the ball head from the ball head receptacle.

According to an advantageous embodiment, the ball head receptacle may have a curved bottom part, to which a cylindrical space adjoins in the axial direction. The cylindrical space of the base body is used in a favorable manner for introducing the ball head into the ball head receptacle. The cylindrical space also provides space for receiving the locking ring and is larger in diameter than the ball head. After insertion, the securing element can be formed by forming the wall of the body or by inserting the securing ring. In this way, then the ball head of the support rod is held in the ball head receptacle and can not slide out again or only with great effort. The curved bottom part is advantageously adapted in the contact area with the ball head to the outer contour of the ball head, so that the ball head is easily pivoted. At the same time, the curved bottom part offers a defined end position of the ball head in the axial direction. The arched area is advantageously about as deep as the radius of the ball head.

According to an advantageous embodiment of the circlip may be placed with bias against a wall of the ball head socket. Due to the radial preload an axial securing of the ball head is already possible. Also, so the circlip itself is secured against losing, since it is liable at least on the basis of static friction on the wall of the ball head receptacle, depending on the size of the bias. If the ball head receptacle has an undercut, the retaining ring is secured against unintentional spring-out with high security.

According to an advantageous embodiment, the retaining ring may be interrupted at its periphery. The circlip can be reduced for mounting with a suitable tool in the scope and introduced into the ball head receptacle and then expand again in the scope and bear against the wall of the ball head receiving radially biased. For this purpose, the inner diameter of the ball head receptacle in the intended contact area with the retaining ring and the outer diameter of the locking ring can be suitably matched to one another.

According to an advantageous embodiment, the retaining ring may have a curvature radially inwardly. With particular advantage, this curvature can be formed symmetrically to a center of a longitudinal axis of the securing ring. This allows a particularly low-abrasion contact between circlip and ball head, so that even higher purity requirements can be met. In addition, such a radially inwardly inclined curvature allows favorable freedom of movement over a large angular range for the support rod.

According to an advantageous embodiment, the retaining ring may be formed of plastic. The ball head may advantageously be made of metal. The pairing metal / plastic is particularly favorable to avoid abrasion. This represents a great advantage in the operation over life of the eccentric adjusting device, since the support rod but it moves considerably against the piston and their angular position against the piston changed frequently, so that quite friction can occur.

According to an advantageous embodiment of the base body and the annular body may be formed of a material having the same thermal expansion coefficient, in particular be formed of the same material. For a permanent and reliable contact of body and ring body to each other and thus also fixed position of the sealing ring on the piston, it is advantageous if the base body and ring body do not move against each other. Due to the interference fit of the annular body on the base body, this is also the case as long as the materials used have the same thermal expansion coefficients. It is very advantageous if the base body and the ring body are made of the same material, since then this condition is fulfilled automatically.

According to a further aspect of the invention, a connecting rod, in particular with an eccentric adjusting device for adjusting an effective connecting rod length, proposed with at least one piston which is displaceably guided in a hydraulic chamber and in which a support rod of the eccentric adjusting device is mounted, wherein the piston is provided divided and has a main body and a ring body mounted thereon, wherein by means of the annular body a sealing ring on the piston can be fastened and in particular the connecting rod has means for adjusting an effective connecting rod length. In particular, a connecting rod is proposed with at least one ball bearing with a ball head arranged on the support rod, wherein the ball head is mounted in a ball head receptacle, and wherein the ball head is secured on its outer surface in the ball head receptacle by a locking ring against sliding out of the ball head receptacle. The ball bearing is inexpensive to manufacture, easy to assemble and offers a high pull-out force against pulling out of the ball head from the ball head.

According to a further aspect of the invention, an internal combustion engine having an adjustable compression ratio with at least one Connecting rod as described above.

Brief description of the drawings

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

They show by way of example:

1 in longitudinal section a connecting rod according to the prior art;

2 a first embodiment of a piston according to an embodiment of the invention in a longitudinal sectional view; and

3 a further embodiment of a piston according to an embodiment of the invention in longitudinal section.

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference numerals. The figures are merely examples and are not intended to be limiting.

The known connecting rod 100 in 1 has an upper connecting rod eye 12 on, which is provided for receiving a piston pin, not shown. This piston pin is firmly inserted in a conventional manner in a combustion chamber piston of the internal combustion engine. The upper connecting rod eye 12 is over the connecting rod 100 with the bottom in the figure, large connecting rod eye 13 connected.

The upper connecting rod eye 12 is by means of a eccentric 106 trained bearing component about a pivot axis 102 pivotable, offset parallel to the longitudinal axis 104 of the upper connecting rod eye 12 lies. For this purpose, the eccentric in an opening 108 a lever 11 used and with the lever 11 connected, from which two arms extend diametrically each other fort where support rods 18 are articulated. The support rods 18 are hinged at the other end with the pistons 14 connected, which in a bore 42 the hydraulic chambers 16 are movable movable. Each one of the pistons moves 14 from its associated hydraulic chamber 16 off while the other piston 14 in its associated hydraulic chamber 16 retracts. Thus it is possible the eccentric 106 inside a bore of the connecting rod 100s around the pivot axis 102 to move. These are the support bars 18 for example, with a connecting joint 10 in recordings of pistons 14 stored and screwed there with cross bolts. The support rods 18 are with one in with the support rods 18 cooperating hydraulic chambers 16 prevailing hydraulic pressure applied, the pistons 14 in the hydraulic chambers 16 are guided displaceably. Thus, the distance of the upper connecting rod bearing eye 12 to a connecting rod bearing axis 110 of the in the figure lower connecting rod eye 13 be changed as an effective connecting rod length and so on the at the upper connecting rod eye 12 stored support rods 18 a variable compression in the combustion chamber of an internal combustion engine can be effected.

2 shows a first embodiment of a piston according to the invention 14 as he especially for a connecting rod 100 is provided with an eccentric adjusting device for adjusting an effective connecting rod length. How out 2 it can be seen, is the piston 14 in a hydraulic chamber 16 slidably guided and in which a support rod 18 the eccentric adjusting device is mounted, provided split and has a main body 22 and a ring body mounted thereon 24 on, by means of the ring body 24 a sealing ring 26 on the piston 14 is fastened.

The sealing ring 26 is on the ring body 24 arranged and has a rectangular cross section, whereby a good sealing effect with a small gap between the piston outer surface and bore 42 the hydraulic chamber 16 can be achieved. Also, such a rectangular cross section can have a wide running surface of the seal 26 on the sliding surface of the hole 42 the hydraulic chamber 16 form. As a result, a favorable wear behavior is achieved at the same time good sealing effect, which contributes to an overall economic operation of the eccentric adjusting device

The sealing ring 26 is in a radially outer annular recess 28 of the ring body 24 arranged and is after assembly of the ring body 24 on the body 22 in the axial direction L between the ring body 24 and the body 22 kept free of play. This simplifies assembly. Also, there is a risk that the sealing ring 26 is damaged during assembly, thereby also reduced. Also, the sealing ring 26 be so pre-centered. The sealing ring 26 can also be cheap between basic body 22 and ring body 24 be held so that the sealing ring 26 during operation of the piston 14 remains in its position. In addition, the wear of sealing ring can be 26 and sliding surface of the hydraulic chamber 16 make it cheap. Tolerances during assembly can be advantageously maintained.

The ring body 24 is intended as a press ring, which on an annular shoulder 40 of the basic body 22 is pressed on. The press fit is a very simple and flexible way to mount a body to another body while forming a firm and lasting connection. The sealing ring 26 is first placed over the press-singling, which then on the body 22 is pressed on. The sealing ring 26 can be so cheap between body 22 and ring body 24 be held so that the sealing ring 26 during operation of the piston 14 remains in its position.

Alternatively, the sealing ring 26 also directly on the ring-shaped heel 40 of the basic body 22 be arranged and after the assembly of the ring body 24 on the body 22 in the axial direction L between the ring body 24 and the body 22 be held.

It is particularly advantageous that the sealing ring 26 is formed of a non-flexible material such as gray cast iron. Such seals have good running properties and improved wear behavior and are not "activated" by the pressure and thus forced apart. Ideally, the seal touches 26 not the hole 42 the hydraulic chamber 16 and it forms between poetry 26 and bore 42 a lubricating film. Due to the wide bearing surface of the sealing ring 26 on the hole 42 the hydraulic chamber 16 a favorable sealing effect is achieved.

It is a projection of an outer diameter of the sealing ring 26 to an outer diameter of the main body 22 and / or the ring body 24 of at least 10 microns, preferably at least 15 microns, most preferably at least 20 microns, whereby a good sealing effect of the sealing ring 26 when moving in the hole 42 the hydraulic chamber 16 and a favorable wear behavior can be achieved over the duration of the operation.

The main body 22 is as a ball head socket 30 for one at the support bar 18 arranged ball head 20 of the ball bearing 10 trained and the ball head 20 is on its outer surface in the ball head socket 30 by a securing element 52 against slipping out of the ball head socket 30 secured, with the fuse element 52 is formed in particular with a radially inwardly projecting undercut. The ball head socket 30 allows a very large freedom of movement of the support rod 18 relative to the piston 14 because the support bar 18 can move over a large angle range.

The fuse element 52 For example, as an at least partially deformable wall 44 of the basic body 22 be educated. By deformation of the wall 44 of the basic body 22 can the fuse element 52 Produce in a very simple and inexpensive way with the help of a tool by forming appropriate.

Alternatively, the fuse element 52 as in the case of 2 illustrated embodiment, in particular as a retaining ring 50 be educated. The circlip 50 may be formed symmetrically in particular along its longitudinal axis, so that a mounting can be done without confusion. Alternatively, the embodiment may also be asymmetrical. The ball head is advantageous 20 in the ball head socket 30 swiveling and at the same time axially only with high pull-out force from the ball head receptacle 30 pulled out.

The ball head socket 30 includes a curved bottom part 32 attached to the outer contour of the ball head 20 is adjusted and on the ball head 20 can slide to tilts the support rod 18 to enable. In the axial direction to the open end of the ball head receptacle 30 towards a cylindrical space closes 34 in which the circlip 50 is arranged.

The ball head socket 30 has an undercut at its open end 36 on top of the circlip 50 in the ball head socket 30 secures axially. This is a high security against sliding out or pulling out of the locking ring 50 and with it the ball head 20 from the ball head socket 30 given.

The ball head socket 30 has a curved bottom part 32 on, in the axial direction of a cylindrical space 34 followed. The cylindrical space 34 of the basic body 22 used in a favorable manner for insertion of the ball head 20 in the ballhead socket 30 , The cylindrical space 34 provides space for receiving the locking ring 50 and is larger in diameter than the ball head 20 , The arched bottom part 32 is in contact with the ball head 20 advantageous to the outer contour of the ball head 20 adjusted so that the ball head 20 is easily swiveled. At the same time offers the arched bottom part 32 a defined end position of the ball head 20 in the axial direction. The arched area 32 is advantageously about as deep as the radius of the ball head 20 ,

The circlip 50 lies down with pretension against a wall 38 the ball head socket 30 , This is the circlip 50 interrupted, in particular slotted, and can be pressed together for assembly and in the ball head socket 30 be used. In addition, can the slotted circlip 50 just over the support bar 18 slide.

The circlip 50 is formed for example of plastic and has its in the installed state the ball head 20 facing end face a radially inwardly facing curvature 54 on that an axial movement of the ball head 20 limited. At the same time, the ball head with its outer surface on the vault 54 slide at a tilt. This allows a particularly low-abrasion contact between the circlip 50 and ball head 20 , so that even higher purity requirements can be met. In addition, such a radial inwardly inclined curvature allows 54 a favorable freedom of movement over a large angular range for the support rod 18 ,

The main body 22 and the ring body 24 are formed of a material having the same thermal expansion coefficient, in particular formed from the same material. For a permanent and reliable contact of body 22 and ring body 24 to each other and thus also fixed position of the sealing ring 26 on the piston 14 It is advantageous if basic body 22 and ring body 24 do not move against each other.

3 shows a further embodiment of the piston 14 according to an embodiment of the invention. This differs only in the shape of the ring body 24 , which has a dead volume in the hydraulic chamber 16 certainly. In 3 is the ring body 24 at the free, the support rod 18 opposite end provided with a chamfer. So can the interior of the hydraulic chamber 16 , which can also be equipped with rounded edges, be better utilized. In this way, at maximum retracted piston 14 in the hydraulic chamber 16 the free residual volume of the hydraulic chamber 16 reduced.

The piston 14 will be beneficial for a connecting rod 100 used, which is used for example in an internal combustion engine with adjustable compression ratio application, wherein the connecting rod 100 as described above, may comprise means for adjusting the effective connecting rod length.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102005055199 A1 [0003]

Claims (22)

Piston ( 14 ), in particular for a connecting rod ( 100 ) with an eccentric adjusting device for adjusting an effective connecting rod length, which is in a hydraulic chamber ( 16 ) is slidably guided and in which a support rod ( 18 ) of the eccentric adjusting device is mounted, characterized in that the piston ( 14 ) and a basic body ( 22 ) and a ring body ( 24 ), wherein by means of the annular body ( 24 ) a sealing ring ( 26 ) is fastened on the piston. Piston according to claim 1, characterized in that the sealing ring ( 26 ) on the ring body ( 24 ) is arranged. Piston according to claim 1 or 2, characterized in that the annular body ( 24 ) is provided as a pressing ring, which on an annular shoulder ( 40 ) of the basic body ( 22 ) is aufpressbar. Piston according to one of the preceding claims, characterized in that the sealing ring ( 26 ) has a rectangular cross-section. Piston according to one of the preceding claims, characterized in that the sealing ring ( 26 ) in a radially outer annular recess ( 28 ) of the ring body ( 24 ) is arranged and after the assembly of the annular body ( 24 ) on the base body ( 22 ) in the axial direction (L) between the annular body ( 24 ) and the basic body ( 22 ) is held. Piston according to one of claims 1 to 4, characterized in that the sealing ring ( 26 ) on the annular shoulder ( 40 ) of the basic body ( 22 ) is arranged and after the assembly of the annular body ( 24 ) on the base body ( 22 ) in the axial direction (L) between the annular body ( 24 ) and the basic body ( 22 ) is held. Piston according to one of the preceding claims, characterized in that the sealing ring ( 26 ) is formed of a non-elastic material. Piston according to claim 7, characterized in that the sealing ring ( 26 ) is formed from gray cast iron material. Piston according to one of the preceding claims, characterized in that a projection of an outer diameter of the sealing ring ( 26 ) to an outer diameter of the main body ( 22 ) and / or the ring body ( 24 ) of at least 10 microns, preferably at least 15 microns, most preferably at least 20 microns is provided. Piston according to one of the preceding claims, characterized in that the basic body ( 22 ) as a ball head receptacle ( 30 ) for one on the support rod ( 18 ) arranged ball head ( 20 ) is trained. Piston according to claim 10, characterized in that a securing element ( 50 ) is provided, which the ball head ( 20 ) on its outer surface in the ball head receptacle ( 30 ) against slipping out of the ball head receptacle ( 30 ), whereby the security element ( 50 ) is formed in particular with a radially inwardly projecting undercut. Piston according to claim 11, characterized in that the securing element ( 52 ) as at least partially deformable wall ( 44 ) of the basic body ( 22 ) is trained. Piston according to claim 11, characterized in that the securing element ( 52 ) as a retaining ring ( 50 ) is trained. Piston according to claim 13, characterized in that the ball head receptacle ( 30 ) at its open end an undercut ( 36 ) having the retaining ring ( 50 ) in the ball head receptacle ( 30 ) secures axially. Piston according to one of claims 10 to 14, characterized in that the ball head receptacle ( 30 ) a curved bottom part ( 32 ), to which in the axial direction a cylindrical space ( 34 ). Piston according to one of the 13 to 15, characterized in that the retaining ring ( 50 ) with prestress against a wall ( 38 ) of the ball head receptacle ( 30 ) is placed. Piston according to one of claims 13 to 16, characterized in that the retaining ring ( 50 ) is interrupted at its periphery. Piston according to one of claims 13 to 17, characterized in that the retaining ring ( 50 ) radially inwardly a curvature ( 54 ) having. Piston according to one of claims 13 to 18, characterized in that the retaining ring ( 50 ) is made of plastic. Piston according to one of the preceding claims, characterized in that the basic body ( 22 ) and the ring body ( 24 ) are formed from a material having the same coefficient of thermal expansion, in particular formed from the same material. Connecting rod ( 100 ) with at least one piston ( 14 ) according to one of the preceding claims, wherein in particular the connecting rod ( 100 ) Has means for adjusting an effective connecting rod length. Internal combustion engine with an adjustable compression ratio with at least one connecting rod ( 100 ) according to claim 21.

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