CN110645089A

CN110645089A - Check valve for a connecting rod of an internal combustion engine with variable compression ratio and connecting rod with a check valve

Info

Publication number: CN110645089A
Application number: CN201910420094.0A
Authority: CN
Inventors: 亚历山大·穆德拉; 迪特玛·舒尔茨
Original assignee: 1 Yixiou Holdings Ltd
Current assignee: 1 Yixiou Holdings Ltd; Eco Holding 1 GmbH
Priority date: 2018-06-27
Filing date: 2019-05-20
Publication date: 2020-01-03
Also published as: CN110645090A; CN110645385A; DE102018116966A1; CN110645385B; DE102018117451A1; DE102018118449A1

Abstract

The invention relates to a non-return valve (59, 60) for a connecting rod (1) of an internal combustion engine having a variable compression ratio, said connecting rod having at least one rod-side hydraulic chamber (2, 4) which can be connected to a bearing shell (10) and/or a tank of the connecting rod (1) by means of the non-return valve (59, 60), comprising a valve body (61) having a fluid path between a first valve opening (22) and a second valve opening (23) in the valve body (61) and a closing element (24) which can be axially displaced along a valve longitudinal axis (L) in the valve body (61) and which can be brought into contact with a valve seat (25) in a stop position of the non-return valve (59, 60) and with a stop (26) in an open position. According to the invention, the valve body (61) has a damping piston (71) for damping the end position of the plunger (62) of the connecting rod (1). The invention also relates to a connecting rod (1) with such a non-return valve (59, 60) for an internal combustion engine with a variable compression ratio.

Description

Check valve for a connecting rod of an internal combustion engine with variable compression ratio and connecting rod with a check valve

Technical Field

The present invention relates to a check valve having a connecting rod of an internal combustion engine with a variable compression ratio and a connecting rod having such a check valve.

Background

In internal combustion engines, high compression factors have a positive effect on the efficiency of the internal combustion engine. Compression ratio is generally understood as the ratio of the total cylinder volume before compression to the remaining cylinder volume after compression. However, in internal combustion engines with external ignition, in particular gasoline engines, with a fixed compression ratio, the compression ratio can only be selected so high that so-called "knocking" of the internal combustion engine is avoided during full-load operation. However, for the partial load region of the internal combustion engine which occurs much more frequently, i.e. with a smaller cylinder filling, the compression ratio can be selected to have a higher value without "knocking" occurring. If the compression ratio can be variably adjusted, the important partial load range of the internal combustion engine can be improved. For adjusting the compression ratio, systems with variable connecting rod length are known, for example, which actuate an eccentric adjustment of the connecting rod by means of a hydraulic switching valve.

Such a connecting rod is known, for example, from DE102012112461a1 and comprises an eccentric adjustment device for adjusting the effective connecting rod length, which has an eccentric that interacts with an eccentric lever, and two plungers, which are each guided displaceably in a hydraulic chamber and in which an eccentric rod of the eccentric adjustment device that acts on the eccentric lever is mounted. The actuating path of the eccentric adjustment device can be adjusted by means of a switching valve. The effective link length is changed by changing the adjustment path. Therefore, the compression ratio of the internal combustion engine can be controlled. A check valve in the connecting rod prevents return flow of hydraulic fluid from the hydraulic chamber to the supply port or the tank, respectively.

For this purpose, a suitable non-return valve is known from DE102012112481a 1.

Disclosure of Invention

The object of the present invention is to provide an improved check valve which has a high degree of reliability and a long service life and which can be produced in a simple manner.

Another object of the invention is to provide an improved connecting rod with such a non-return valve, which has a high reliability and a long service life.

A non-return valve for a connecting rod of an internal combustion engine with a variable compression ratio is proposed, which connecting rod has at least one rod-side hydraulic chamber, which can be connected to a bearing shell and/or a tank of the connecting rod by means of the non-return valve. The check valve comprises a valve body having a fluid path in the valve body between a first valve port and a second valve port, and a closing element which is axially displaceable in the valve body along a valve longitudinal axis and which can be brought into contact with a valve seat in a stop position of the check valve and with a stop in an open position.

According to the invention, the valve body has a damping piston for damping the end position of the plunger of the connecting rod.

The first port is preferably an inlet and the second port is preferably an outlet of a check valve.

Advantageously, with the non-return valve arranged directly in the lower part of the hydraulic chamber or at the end of the lower part of the hydraulic chamber, i.e. at the bottom of the chamber, it is possible to avoid: due to the low filling degree of the chamber with hydraulic fluid, for example oil, the supporting piston in the hydraulic chamber can no longer be braked sufficiently by the outlet throttle and is caused to rest at too high a speed on the chamber bottom of the hydraulic chamber. This can lead to excessively high loads, which can damage the lever assembly parts of the connecting rod, in an unfavorable case. The use of a non-return valve in the connecting rod makes it possible to achieve an end position damping, in particular shortly before the plunger strikes the chamber bottom of the hydraulic chamber, which reduces the load overshoot.

In a first step, the plunger is lifted from the chamber bottom. The hydraulic chamber may be supplied with oil through a check valve and discharge the oil through a discharge hole.

In a second step, the plunger, when moving downward toward the chamber bottom, strikes the damping piston and closes off the central bore in the damping piston with its end face. Thereby, a volume of oil inside the check valve surrounds the plunger. The closing process is advantageously carried out directly by the plunger and not step-wise as in the case of a closed-sided outlet bore. The oil can only be drained through leakage. Depending on the viscosity of the oil, the plunger that occurs is braked and thus the impact on the chamber bottom is damped.

In a third step, the stroke of the damping piston is exhausted and the plunger strikes against a valve housing, which is defined as the end stop of the plunger.

In an advantageous embodiment, a spring element, for example a disk spring, can be arranged between the damping piston and the valve body, which spring element can bring about an additional damping of the damping element. Furthermore, if the plunger is lifted off the damping element again, the spring element can bring the damping element into its initial position, so that the damping element can perform its damping function in an advantageous manner when the plunger is lowered again. The stroke of the damping piston is expediently selected such that the permissible spring distance of the spring element is not exceeded.

If the plunger is moved again in the opposite direction, the cup spring ensures that the damping piston is moved again to its initial position (first step) and can thus damp the next impact as described above.

With the arrangement according to the invention of the check valve and the damping element, the hydraulic chamber is extended by the height of the check valve compared to the connecting rod of the prior art and is directly fitted into the check valve. Thereby, a new end stop for the plunger is obtained. By means of such a design, the diameter of the hydraulic chamber can be made larger, thereby providing structural advantages. Furthermore, the usual chamfer at the end below the plunger can be omitted, thereby increasing the plunger guide length and allowing more freedom in design.

The recess and the overflow channel in the housing of the check valve allow the discharge channel to be arranged in many variable ways, which provides more freedom in design and thus makes it possible to avoid holes in mechanically critical areas if necessary.

The recess in the valve housing can also be used as a lateral recess for axial fixing by pressing the material of the connecting rod base into the recess.

According to an advantageous embodiment, the spring element is at least functionally arranged between the valve body and the damping piston. The spring element is at least arranged to act between the valve body and the damping piston, so that the damping piston influences the spring element and thus indirectly the valve body. The spring element can also be arranged geometrically between the valve body and the damping piston, so that the valve body, the spring element and the damping element follow one another in a geometric sequence.

Such a spring element may cause additional damping of the damping element. Furthermore, if the plunger is lifted off the damping element again, the spring element can bring the damping element into its initial position, so that the damping element can perform its damping function in an advantageous manner when the plunger is lowered again. The stroke of the damping piston is expediently selected such that the permissible spring distance of the spring element is not exceeded. If the plunger is moved again in the opposite direction, the cup spring ensures that the damping piston moves again to its initial position and can thus damp the next impact as described above.

According to an advantageous embodiment, the valve body can have at least one overflow channel extending along the longitudinal valve axis. Through which hydraulic fluid can be conducted in a suitable manner through the non-return valve into the outlet opening. Thus, the drain hole may be provided somewhere in the connecting rod where it facilitates machining of the connecting rod and/or load distribution in the connecting rod.

According to an advantageous embodiment, the at least one overflow channel can be arranged on the outside of the valve housing. The overflow channel on the outside of the valve housing can be inserted radially into the valve housing, for example, by impact twisting.

According to an advantageous embodiment, the closing element and the damping piston are successive to one another in the axial direction. The axial arrangement of the damping piston and the closing element relative to each other facilitates the distribution of the force of the damping hydraulic fluid within the non-return valve. Jamming of the closing element and/or the damping piston can advantageously be avoided in this way.

According to an advantageous embodiment, the damping piston acts in the same direction as the closing element. This achieves that the non-return valve is reliably closed when the plunger is seated on the damping piston. The closing function of the damping piston is advantageously performed directly by the plunger of the hydraulic cylinder of the connecting rod and not stepwise by the plunger as in the case of the outlet opening on the closing side.

According to an advantageous embodiment, the valve body has an annular recess. The recess in the housing of the check valve allows the outlet channel to be arranged in many variable ways, which gives more freedom in design and thus makes it possible to avoid holes in critical areas if necessary. The recess in the valve housing can also be used as a lateral recess for axial fixing by pressing the material of the connecting rod base into the recess.

According to an advantageous embodiment, the material of the connecting rod is inserted into the circumferential groove by means of a suitable deformation process in order to fix the valve body in the connecting rod. By deforming, for example, a relatively thin web in the valve body via a radial bore, the material of the connecting rod can be pressed into the annular groove and thus the non-return valve can be reliably fixed in its position in the connecting rod or in the hydraulic chamber.

According to an advantageous embodiment, the circumferential groove can have a fluid connection between the at least one overflow channel and a discharge opening provided in the connecting rod. In this way, hydraulic fluid can be appropriately tapped from the hydraulic chamber, for example throttled.

According to an advantageous embodiment, the valve body can have a through-opening arranged transversely to the longitudinal valve axis for receiving a cylindrical pin for the loss-proof arrangement of the closing element in the valve body. By means of the cylindrical pin, the stop of the closing element can be realized in a suitable manner. The cylindrical pin advantageously prevents the closure element from falling out of the interior of the valve body. The closing element can therefore also be mounted simply.

According to an advantageous embodiment, the closing element is designed as a sphere. The ball as the closing element ensures a reliable closing function and has the advantage that the closing element does not have to be mounted in an oriented manner. The ball can reliably close the correspondingly complementary valve seat.

According to an advantageous embodiment, the valve seat can be at least partially formed in the shape of a spherical cap. In this way, the valve seat can be reliably and effectively closed with a ball as the closing element.

According to a further aspect of the invention, a connecting rod for an internal combustion engine with a variable compression ratio is proposed, which connecting rod has at least one hydraulic chamber and a plunger guided displaceably therein, wherein the hydraulic chamber can be connected to a bearing shell and/or a tank of the connecting rod as described above by means of a non-return valve.

According to a further aspect of the invention, a connecting rod for an internal combustion engine with a variable compression ratio is proposed, which connecting rod has at least one hydraulic chamber and a plunger guided displaceably therein, wherein the hydraulic chamber can be connected to a bearing shell and/or a tank of the connecting rod by means of a check valve.

According to the invention, the non-return valve is arranged directly in the lower part of the hydraulic chamber and comprises a damping piston for damping the end position of the plunger.

Advantageously, with the non-return valve arranged directly in the lower part of the hydraulic chamber or at the end of the lower part of the hydraulic chamber, i.e. at the bottom of the chamber, it is possible to avoid: due to the low filling degree of the chamber with hydraulic fluid, for example oil, the supporting piston in the hydraulic chamber can no longer be braked sufficiently by the outlet throttle and is caused to rest at too high a speed on the chamber bottom of the hydraulic chamber. This means that, in unfavorable cases, too high a load can result, which can damage the lever assembly parts of the connecting rod. The use of a non-return valve in the connecting rod makes it possible to achieve end position damping, in particular shortly between the impact of the plunger on the bottom of the hydraulic chamber, which reduces said overload.

According to an advantageous embodiment, the plunger closes the valve opening of the check valve with its end face. Advantageously, the valve port can be closed and opened in a defined manner. It is possible to avoid a gradual closing or opening of the valve opening, the throughflow cross section of which is gradually closed or opened depending on the axial position of the plunger. The valve port is closed when the end face of the plunger is attached, and the valve port is opened when the end face of the plunger is lifted.

Advantageously, the direction of action of the plunger and of the damping piston is the same as the direction of movement of the closing element.

According to an advantageous embodiment, a spring element is arranged between the valve body of the check valve and the damping piston. Such a spring element may cause additional damping of the damping element. Furthermore, if the plunger is lifted off the damping element again, the spring element can bring the damping element into its initial position, so that the damping element can perform its damping function in an advantageous manner when the plunger is lowered again. The stroke of the damping piston is expediently selected such that the permissible spring distance of the spring element is not exceeded. If the plunger is moved again in the opposite direction, the cup spring ensures that the damping piston moves again to its initial position and can thus damp the next impact as described above.

According to an advantageous embodiment, the non-return valve can be pressed into the connecting rod body or the connecting rod cover. In this way, the check valve can be reliably installed in the connecting rod. Such mounting of the non-return valve can also be achieved in a simple manner. A reliable seal can be achieved between the non-return valve and the connecting rod body or the connecting rod cover by means of the pressed-in non-return valve.

Drawings

Other advantages result from the following description of the figures. Embodiments of the invention are schematically illustrated in the drawings. The drawings, description and claims include many combinations of features. Other reasonable combinations of these features can also be considered individually and summarized in a manner consistent with the purpose by those skilled in the art.

Wherein:

fig. 1 shows a schematic representation of a connecting rod according to the invention with a non-return valve for an internal combustion engine of a motor vehicle with a variable compression ratio;

fig. 2 shows an enlarged longitudinal section through the connecting rod of fig. 1 with a non-return valve according to a first embodiment of the invention in a state in which the plunger is lifted from the bottom of the hydraulic chamber;

FIG. 3 shows the connecting rod of FIG. 2 in a state where the plunger contacts the damping piston;

FIG. 4 shows the connecting rod of FIG. 2 with the plunger at the end stop;

fig. 5 shows a longitudinal section through a non-return valve according to another embodiment of the invention with a spring element between the valve body and the damping piston;

FIG. 6 shows an isometric view of the check valve of FIG. 5;

FIG. 7 shows an isometric view of a check valve according to another embodiment of the present invention;

fig. 8 shows an enlarged longitudinal section through the connecting rod with the non-return valve of fig. 7 in a state in which the plunger is lifted from the bottom of the hydraulic chamber.

Detailed Description

The same reference numbers will be used throughout the drawings to refer to the same or like parts. The drawings are only for purposes of illustration and are not to be construed as limiting.

Fig. 1 shows a schematic illustration of a known connecting rod 1 for a variable compression ratio internal combustion engine of a motor vehicle, which connecting rod has

check valves

59, 60. The connecting rod 1 comprises an eccentric adjustment device, not shown, for adjusting the effective connecting rod length. The eccentric wheel adjusting device is provided with an eccentric wheel which is matched with the eccentric lever to act. The control path of the eccentric adjustment device can be adjusted by means of a control valve 16, which is not described in detail.

The rotation of the adjustable eccentric adjustment device is initiated by the inertial and load forces of the internal combustion engine, which act on the eccentric adjustment device during the operating cycle of the internal combustion engine. During the operating cycle, the direction of the action of the force acting on the eccentric adjustment device changes continuously. The rotary or adjusting movement is assisted by a piston which is loaded with hydraulic fluid, in particular oil, and which is integrated in the connecting rod 1, or which prevents the eccentric adjusting device from being reset as a result of the changing force direction of the force acting on the eccentric adjusting device.

The plunger is effectively connected to the eccentric base of the eccentric adjusting device on both sides by means of an eccentric rod. The plungers are arranged displaceably in the hydraulic chambers 2, 4 and are acted upon by hydraulic fluid from the bearing shell 10 of the connecting rod bearing bore 11 via

hydraulic fluid lines

6, 8 via

check valves

59, 60. In this case, the non-return valve prevents a return flow of hydraulic fluid from the hydraulic chambers 2, 4 into the

hydraulic fluid lines

6, 8, into the bearing shell 10 of the connecting rod bearing bore 11 or into the tank and enables a re-suction of hydraulic fluid into the hydraulic chambers 2, 4. The hydraulic chambers 2, 4 are connected to further hydraulic fluid lines, not shown, which cooperate with the switching valve 16. The switching valve 16 is likewise connected to the bearing shell 10 via a hydraulic fluid line 18.

Two

non-return valves

59, 60 are respectively arranged at the lower end of the hydraulic chamber 2 or 4 and are connected to the bearing shell 10 via

hydraulic fluid lines

6 or 8. The

non-return valves

59, 60 have a terminal position damping for the plunger guided in the hydraulic chamber 2.

The first valve port 22 is connected as an inlet to the

hydraulic fluid line

6 or 8 and thus to the bearing shell 10 of the connecting rod 1, and the second valve port 23 is connected as an outlet to the hydraulic chamber 2 or 4, wherein a valve passage direction 80 of the fluid entering the inlet and exiting through the outlet is defined between the inlet and the outlet.

In an alternative embodiment of the connecting rod, the

check valves

59, 60 may be provided in the connecting rod cap 7 instead of in the connecting rod body 9. In both embodiments, the check valve can be pressed in a targeted manner.

Due to the low filling level of the oil chamber of the hydraulic chamber 2, it may happen that the plunger can no longer be fully braked in the hydraulic chamber and is caused to rest on the chamber bottom at too high a speed, so that in adverse cases too high a load can damage the lever assembly components of the eccentric adjusting device, not shown.

In fig. 2 to 4, the effect of damping the end position of the guided plunger 62 in the hydraulic chamber 2 is represented in different positions of the plunger 62. Fig. 2 shows an enlarged longitudinal section through the connecting rod 1 of fig. 1 with the non-return valve 60 according to a first embodiment of the invention in a state in which the plunger 62 is lifted from the bottom 72 of the hydraulic chamber 2, while fig. 3 shows the connecting rod 1 in a state in which the plunger 62 contacts the damping piston 71, and fig. 4 shows the connecting rod 1 in a state in which the plunger 62 is at an end stop.

The non-return valve 60 is arranged directly below the hydraulic chamber 2 and comprises a valve body 61 with a fluid path in the valve body 61 between a first valve port 22 as inlet and a second valve port 23 as outlet, and a closing element 24 which is axially movable in the valve body 61 along the valve longitudinal axis L and which can be brought into abutment against the valve seat 25 in a stop position of the non-return valve 60 and against the stop 26 in an open position. The check valve 60 has a damping piston 71 for damping the end position of the plunger 62 of the connecting rod 1. The damping piston 71 is guided axially in a valve housing 74.

The closing element 24 and the damping piston 71 are successive to one another in the axial direction. The damping piston 71 acts in the same direction as the closing element 24.

The closing element 24 is designed as a sphere, wherein the valve seat 25 is designed in a manner suitable for the purpose at least in some areas as a spherical cap.

If the plunger 62 is lifted from the chamber bottom 72 (shown in fig. 2), the hydraulic chamber 2 is either supplied with oil via the non-illustrated switching valve 60 via the inlet 22 and the outlet 23 or is emptied via the outlet 63, as shown in fig. 5, depending on the position of the switching valve.

If the plunger 62 touches the damping piston 71 (shown in fig. 3), it closes off the bore 75 of the damping piston 71 with its end face. Thus, a volume of oil between the check valve 60 and the plunger 62 surrounds the plunger. The oil can only be drained through leakage. Depending on the viscosity of the oil, the emerging plunger 62 is braked and thus the impact on the chamber bottom 72 is damped.

If the stroke of the damping piston 71 is exhausted, the plunger 62 strikes a valve housing 74 (shown in fig. 4), which is thus defined as an end stop for the plunger 62. If the plunger 62 is moved again in the opposite direction, the damping piston 71 can be moved again to its initial position and the next impact can thus be damped as described above.

Fig. 5 shows a longitudinal section through a non-return valve 60 according to a further exemplary embodiment of the invention, which has a spring element 73 between the valve body 61 and the damping piston 71.

The construction of the check valve 60 substantially corresponds to the check valve 60 of fig. 2 to 4. The check valve 60 has a damping of the end position of the plunger 60 indicated by dashed lines for guidance in the hydraulic chamber 2, wherein the check valve 60 shown in fig. 5 additionally has a spring element 73.

The spring element 73 is arranged between the valve body 61 and the damping piston 71 in the form of a cup spring. Here, the valve housing 74 comprises the valve body 61, the damping piston 71 and the spring element 73.

If the plunger 62 is moved again in the opposite direction, the spring element 73 ensures that the damping piston 71 is moved again to its initial position in a reliable manner and thus the next impact can be damped as described above.

Furthermore, the spring element 73 can ensure an additional damping of the damping piston 71 when the plunger 62 moves the damping piston 71 toward the chamber bottom 72.

In the embodiment shown in fig. 5, the valve seat 25 is inserted, preferably pressed, into the valve body 61 from the side of the inlet opening 22.

In the embodiment shown in fig. 5, the valve housing 74 has an additional circumferential groove 51. The illustrated recess 51 in the valve housing 74 can serve as a lateral recess for axially fixing the check valve 60 in the installed position in the connecting rod by pressing the material of the connecting rod base body 9 into the recess 51 by means of a suitable deformation process in order to fix the valve housing 74 in the connecting rod 1.

In this regard, FIG. 6 shows an isometric view of the check valve 60 of FIG. 5. As can be seen in fig. 5, the valve housing 74 has an overflow channel 78 extending along the valve longitudinal axis L for discharging oil from the hydraulic chamber 2. The overflow channel 78 is arranged outside the valve housing 74. The groove 51 running around the outside of the valve housing 74 may additionally have a fluid connection between the overflow channel 78 and the outlet 63 provided in the connecting rod 1.

The overflow channel 78 shown in fig. 6 and 7 and the recess 51 in the valve housing 74 allow the outlet opening 63 to be arranged in many variable ways, which provides more freedom in design and thus makes it possible to avoid outlet openings in mechanically critical regions if necessary.

In fig. 7, an isometric view of a check valve 60 according to another embodiment of the invention is shown, which is shown in its installed position in the connecting rod in fig. 8.

The valve body 61 corresponds to the essential features of the exemplary embodiment in fig. 6, but additionally has a through-bore 76, which is arranged transversely to the valve longitudinal axis L and serves to receive a cylindrical pin 77 for the fall-proof arrangement of the closing element 24 in the valve body 61. In fig. 8, the function of the cylindrical pin 77 can be seen.

Fig. 8 shows an enlarged longitudinal section through the connecting rod 1 with the non-return valve 60 from fig. 7 in the state in which the plunger 62 is lifted from the bottom 72 of the hydraulic chamber 2.

The hydraulic chamber 2 can be lengthened by the height of the non-return valve 60 with a final position buffer, so that said non-return valve 60 can be directly inserted as in the embodiment in fig. 8. Thereby, a new end stop for the plunger 62 is obtained. The diameter of the hydraulic chambers 2, 4 can be made larger by such a design, which represents a structural advantage. Furthermore, no chamfers are required on the plunger 62, thereby increasing the plunger guide length and allowing more freedom in design.

As can be seen in fig. 8, the main design of the check valve 60 corresponds to the embodiment shown in fig. 5 with a spring element 73 between the damping piston 71 and the valve body 61, which however additionally has a cylindrical pin 77 arranged in the bore 76 transversely to the valve longitudinal axis L. The cylindrical pin 77 can serve the function of the stop 26 in a purposeful manner, so that the closing element 24 is arranged in the valve body 61 in such a way as to be secured against falling.

Claims

1. A non-return valve (59, 60) for a connecting rod (1) of an internal combustion engine having a variable compression ratio, having at least one rod-side hydraulic chamber (2, 4) which can be connected to a bearing shell (10) and/or a tank of the connecting rod (1) by means of the non-return valve (59, 60),

comprising a valve body (61) having a fluid path in the valve body (61) between a first port (22) and a second port (23), and a closing element (24) which is axially displaceable in the valve body (61) along a valve longitudinal axis (L) and which can be brought into contact with a valve seat (25) in a stop position of the check valve (59, 60) and with a stop (26) in an open position,

the valve body (61) is characterized by comprising a buffer piston (71) for buffering the terminal position of a plunger (62) of the connecting rod (1).

2. Non-return valve according to claim 1, wherein the spring element (73) is at least arranged to act between the valve body (61) and the damping piston (71).

3. Non-return valve according to claim 1 or 2, wherein the valve housing (74) has at least one overflow channel (78) extending along the valve longitudinal axis (L).

4. Non-return valve according to claim 3, wherein the at least one overflow channel (78) is provided outside the valve housing (74).

5. Non-return valve according to one of the preceding claims, wherein the closing element (24) and the damping piston (71) are successive to each other in the axial direction.

6. Non-return valve according to one of the preceding claims, wherein the damping piston (71) acts in the same direction as the direction of movement of the closing element (24).

7. Non-return valve according to one of the preceding claims, wherein the valve body (61) has a circumferential groove (51).

8. A non-return valve according to claim 8, wherein the material of the connecting rod (1) enters the surrounding groove (51) by means of a suitable deformation process for fixing the valve body (41) in the connecting rod (1).

9. Non-return valve according to claim 7 or 8, wherein the surrounding groove (51) has a fluid connection between the at least one overflow channel (78) and a discharge opening (63) provided in the connecting rod (1).

10. Non-return valve according to one of the preceding claims, wherein the valve body (61) has a through-going bore (76) arranged transversely to the valve longitudinal axis (L) for receiving a cylindrical pin (77) for the fall-off-proof arrangement of the closing element (24) in the valve body (61).

11. Non-return valve according to one of the preceding claims, wherein the closing element (24) is configured as a spheroid.

12. The non-return valve according to claim 11, wherein the valve seat (25) is at least partially configured as a spherical cap.

13. Connecting rod (1) for an internal combustion engine with a variable compression ratio, having at least one hydraulic chamber (2, 4) and a plunger (62) guided displaceably in the hydraulic chamber, wherein the hydraulic chamber (2, 4) can be connected to a bearing shell (10) and/or a tank of the connecting rod (1) by means of a non-return valve (59, 60) according to one of the preceding claims.

14. Connecting rod (1) for an internal combustion engine with a variable compression ratio, having at least one hydraulic chamber (2, 4) and a plunger (62) guided displaceably in the hydraulic chamber, wherein the hydraulic chamber (2, 4) can be connected to a bearing shell (10) and/or a tank of the connecting rod (1) by means of a non-return valve (59, 60) according to one of the preceding claims, characterized in that the non-return valve (59, 60) is arranged directly below the hydraulic chamber (2, 4) and comprises a damping piston (71) for damping the end position of the plunger (62).

15. The connecting rod of claim 13 or 14, wherein the plunger (62) closes with its end face the valve port (22) of the check valve (59, 60).

16. The connecting rod of one of claims 13 to 15, wherein a spring element (73) is provided between the valve body (61) of the check valve (59, 60) and the damping piston (71).

17. The connecting rod of any one of claims 13 to 16, wherein the non-return valve (59, 60) is pressed into the connecting rod body (9) or the connecting rod cover (7).