Engine braking device for a valve train of an internal combustion engine

Abstract

The invention relates to an engine braking device for a valve train of an internal combustion engine, comprising a lever-shaped cam follower (10) which is pivotally mounted about a pivot axis (7) and which carries eccentrically thereto a piston (15) which is guided displaceably between a basic position and a contact position, wherein the piston (15) can be transferred from the basic position into the contact position by pressurizing a pressure chamber (22) from a supply line (30), which contact position is selected for establishing contact between the piston (15) and a gas exchange valve (4) or decompression valve in the valve train, and wherein a check valve (28) is also provided which is arranged between the pressure chamber (22) and the supply line (30) and is prestressed in an open state, wherein the check valve (28) is arranged eccentrically to the piston (15).

Description

Field of the invention

[0001] The invention relates to an engine braking device for a valve train of an internal combustion engine, comprising a lever-shaped cam follower which is pivotally mounted about a pivot axis and which carries a piston eccentrically thereto, which is guided displaceably between a basic position and a contact position, wherein the piston can be transferred from the basic position into the contact position by pressurizing a pressure chamber from a supply line, which contact position is selected for establishing contact between the piston and a gas exchange or decompression valve in the valve train, and wherein a check valve is also provided, which is arranged between the pressure chamber and the supply line and is pretensioned in an open state. Furthermore, the invention relates to a valve train for an internal combustion engine with at least one aforementioned engine braking device.

[0002] In the commercial vehicle sector, continuous braking systems are known which can be used to ensure wear-free braking of the respective commercial vehicle, for example to prevent excessive wear and overheating of the braking system when driving on long downhill gradients. In addition to continuous braking systems in the form of retarders, engine braking devices are also frequently used, which can be used to specifically increase the drag torque of a commercial vehicle's internal combustion engine. A common variant is to provide a throttle valve in the exhaust tract of the internal combustion engine, via which a back pressure can be specifically generated. This makes it more difficult for the individual pistons of the internal combustion engine to expel the gas into the exhaust tract, thereby causing a higher drag torque.Alternatively, but mostly also in addition to this, a so-called decompression brake function can often be implemented, in the context of which, at the end of a compression stroke in a valve train of the internal combustion engine, an engine brake device usually deliberately opens one of the exhaust valves or a separate decompression valve of the individual cylinder, whereby less work can be done during the subsequent expansion due to the targeted decompression and, accordingly, braking is also achieved.

[0003] In some cases, an engine braking system consists of a hydraulic brake actuation device and a cam follower supporting the brake actuation device. When the decompression brake function is activated, a piston in the brake actuation device is typically hydraulically moved into a position in which a movement initiated by the piston in the cam follower can be converted into the targeted opening of the respective valve at the end of the compression stroke.

[0004] For example, WO 2023 / 247069 A1 discloses an engine braking device in which a lever-shaped cam follower is equipped with a hydraulic brake actuation device. The cam follower is designed as a rocker arm, which is pivotably mounted in a valve train of an internal combustion engine about a pivot axis and accommodates the brake actuation device at one end of the lever eccentrically to the pivot axis. The brake actuation device comprises a housing fixed by the cam follower, in which a piston is displaceably guided. The piston is preloaded in the housing into a basic position, from which it can be displaced by pressurizing a pressure chamber from a supply line into a contact position, in which a lifting movement introduced into the cam follower can be transmitted to an exhaust valve via the piston.The housing also accommodates a movable pin, which is preloaded into a position by a spring element. In this position, the pin holds a check valve of the brake actuation device in an open state, in which a valve body of the check valve is moved out of a valve seat. The check valve is arranged coaxially with the piston in the cam follower.

[0005] When pressure is applied to the supply line to implement a decompression brake function, the pin is moved against the spring element and subsequently no longer acts on the valve body of the check valve. The check valve also allows pressurization of the pressure chamber and thus causes the piston to move into the contact position. The check valve then prevents hydraulic fluid from escaping from the pressure chamber when the piston comes into contact with the outlet valve. If, on the other hand, the decompression brake function is ended, the pressure drop in the supply line results in the pin moving back, brought about by the spring element, into the position in which the pin moves the valve body out of the valve seat. This allows the hydraulic fluid to escape from the pressure chamber and the piston returns to its home position due to the preload.

[0006] Based on the prior art described above, it is the object of the present invention to provide an engine braking device which is characterized by a simple structure. Summary of the invention

[0007] This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow thereon each provide advantageous developments of the invention. A valve train in which at least one engine braking device according to the invention is provided is further the subject of claim 10.

[0008] According to the invention, an engine braking device comprises a lever-shaped cam follower, which is pivotally mounted about a pivot axis and which eccentrically supports a piston that is displaceably guided between a home position and a contact position. The piston can be moved from the home position to the contact position by applying pressure to a pressure chamber from a supply line. This contact position is selected to establish contact between the piston and a gas exchange or decompression valve in the valve train. A check valve is also provided, which is arranged between the pressure chamber and the supply line and is biased to an open state.

[0009] For the purposes of the invention, a "cam follower" is essentially a transmission element via which a respective actuation lift of an associated lifting cam can be converted into corresponding lifts of one or more gas exchange valves and / or an additional decompression valve. The cam follower of the engine braking device according to the invention is preferably a brake cam follower, which is provided solely for the implementation of a respective decompression braking function in the valve train. Within the scope of the invention, however, the cam follower of the engine braking device according to the invention could also be designed, in addition to being designed for implementing a decompression braking function, for carrying out the gas exchange necessary for the regular operation of the internal combustion engine.

[0010] Particularly preferably, the cam follower is a rocker arm in which the pivotable mounting about the pivot axis is realized in a central section of the lever-shaped cam follower, while the piston of the engine braking device is provided at one end of the cam follower and a contact area for initiating an actuating movement is provided at an opposite end of the cam follower. Alternatively, the cam follower could also, in principle, be a rocker arm, with the pivotable mounting about the pivot axis then being provided in particular at one end of the cam follower, with the piston of the engine braking device being received at an opposite end thereto, and a contact area for initiating an actuating movement being configured in an intermediate central section of the cam follower.In both cases, a roller is rotatably mounted in the cam follower in the respective contact area, whereby contact is then established on the roller with the associated lifting cam when the engine brake device is installed in the valve train.

[0011] The engine braking device has a displaceably guided piston which the cam follower carries eccentrically to its pivot axis. The piston is in particular pot-shaped, i.e. a cross-section of the piston is formed at least substantially by a hollow cylindrical section and a base section closing off the end of this hollow cylindrical section. The piston can be moved from a home position into a contact position by pressurising a pressure chamber, with the pressure in the pressure chamber coming from a supply line. The piston is displaceably guided between the home position and the contact position. The pressure chamber is preferably delimited at least between a component guiding the piston and the pot-shaped piston.

[0012] In its contact position, the piston preferably protrudes far enough from the cam follower that, upon initiating movement into the cam follower in the valve train, the piston can make contact, particularly at the front, with a gas exchange or decompression valve, and can then transfer the movement of the cam follower to this valve. This then causes a corresponding stroke of the gas exchange or decompression valve. In contrast, in its basic position, the piston is pushed back far enough that no contact with the gas exchange or decompression valve can occur.

[0013] Preferably, both the home position and the contact position of the piston are each defined by a mechanical stop, wherein each of these stops is very particularly preferably formed by an adjusting screw which is received on the cam follower in particular concentrically to the piston. In the home position, the pot-shaped piston then comes to rest, in particular at its base section, on an end face of the adjusting screw, thereby preventing further return movement of the piston into the cam follower. The mechanical stop defining the contact position, on the other hand, is formed in particular by a shoulder of the adjusting screw, wherein more preferably a disk is attached to the piston, which disk comes into contact with the shoulder of the adjusting screw when the piston is in the contact position.This ensures that the piston reliably extends to a desired distance relative to the cam follower when it is transferred to its contact position.

[0014] Preferably, the adjusting screw in the cam follower is guided through a through-bore and extends out of the cam follower with an end facing away from the piston, with the adjusting screw then being secured to the cam follower at this end, in particular via a nut. The nut can then be used to adjust the relative position of the adjusting screw to the piston and thus also adjust the mechanical stops.

[0015] The engine braking device according to the invention also provides a check valve, which in particular has a valve body, wherein this valve body is preferably in the form of a ball. The check valve is biased to an open state, in which the check valve is then in a position in which an exchange between the pressure chamber and the supply line can take place. In contrast, when the check valve is closed, it separates the pressure chamber and the supply line from each other.

[0016] The invention now includes the technical teaching that the check valve is arranged eccentrically to the piston. In other words, the check valve is accommodated offset from the piston.

[0017] Such a design of an engine braking device has the advantage that the cam follower can have a simpler structure due to the offset arrangement of the check valve compared to a concentric arrangement with the piston. This also allows for a simpler overall design of the engine braking device.

[0018] According to one embodiment of the invention, the check valve is arranged offset laterally from the piston on a side of the piston facing the pivot axis. This allows for suitable accommodation of the check valve.

[0019] Alternatively, but preferably in addition to the aforementioned embodiment, the check valve is integrated into the cam follower and accommodated in a blind bore, which is arranged in a projection on the cam follower that protrudes beyond a surface facing away from the gas exchange or decompression valve. A connection to the supply line is established in the blind bore on a first side of the check valve, with a connecting line opening on a second side of the check valve, opposite the first side, connecting the blind bore to the pressure chamber.

[0020] An alternative embodiment of the invention is for the check valve to be integrated into the cam follower and accommodated in a blind bore that is inserted transversely through the pressure chamber in the cam follower. A connection to the supply line is established in the blind bore on a side of the check valve facing away from the pressure chamber.

[0021] Alternatively, the check valve is housed in a blind bore, which is inserted into the pivot axis at the level of the cam follower. The supply line opens into the blind bore on a first side of the check valve, while a connection to a connecting line is established on a second side of the check valve, opposite the first side, which connects the blind bore to the pressure chamber.

[0022] According to a further embodiment of the invention, the piston is slidably guided on an outer circumference in a guide bore of a surrounding component between the home position and the contact position, with the surrounding component being fixed on the cam follower side. This advantageously allows for suitable guidance of the piston. This surrounding component is fixed on the cam follower side, i.e., it is immovably connected to the cam follower during operation of the valve train.

[0023] In a further development of the aforementioned embodiment, the guide bore is formed in the cam follower. In this case, the piston is thus slidably guided directly in the cam follower on its outer circumference, as the guide bore is formed in the lever-shaped cam follower. Alternatively, it would also be conceivable within the scope of the invention for the guide bore to be formed in a separate component, which, when the engine brake device is installed in the valve train, is fixed by the cam follower. This component could, for example, be an adjusting screw forming a stop for the piston.

[0024] According to a further embodiment of the invention, the check valve has a valve body that is preloaded into a position in which the valve body moves out of a valve seat provided on the side of the supply line, thereby creating the open state of the check valve. In particular, the preload of the valve body is achieved via a spring element that is supported on the one hand by the valve body and on the other hand by an opening of the supply line. This allows the preload of the check valve in its open state to be realized in a compact manner.

[0025] In a further development of the invention, the piston is preloaded into its home position. This has the advantage that when the pressure chamber is no longer pressurized, the piston returns to its home position. Thus, the engine braking device according to the invention can implement a decompression braking function by applying pressure to the pressure chamber, whereupon the piston moves from its home position to its contact position. To terminate the decompression braking function, the pressure must then be removed, causing the piston to return to its home position due to its preload.

[0026] For reliable operation of the engine braking system, the spring characteristic of the check valve's preload in its open position must be matched to the spring characteristic used to preload the piston into its home position. This is because, once the piston has moved into its contact position and the pressure supply to the supply line is interrupted, the check valve should return to its open state, and the piston should move back toward its home position due to its preload. If this were to occur while the pressure in the pressure chamber is too high, the check valve would close again, thus interrupting the piston's return movement.

[0027] Preferably, the piston is preloaded into its home position by a spring element, which allows the piston to be preloaded into its home position in a reliable manner. As already mentioned above, for reliable operation of the engine braking device, the spring characteristic of this spring element would have to be coordinated with the spring characteristic of the preload of the check valve.

[0028] If the engine braking device according to the invention also features an adjusting screw, the spring element preloading the piston is supported on the one hand by a collar formed on the adjusting screw and on the other hand by the piston. If one of the piston's mechanical stops is also implemented using a disc attached to the piston, the piston-side support of the spring element can then be provided on this disc.

[0029] The invention also relates to a valve train for an internal combustion engine, wherein at least one engine braking device according to one or more of the variants described above is provided in this valve train. A decompression braking function can be easily implemented for each cylinder of the internal combustion engine using the at least one engine braking device according to the invention. Short description of the drawing

[0030] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. It shows: Fig. 1 is a perspective view of part of a valve train of an internal combustion engine; Fig. 2 and Fig. 3 sectional views of the valve train from Fig. 1 in the region of an engine braking device according to a first embodiment of the invention; Fig. 4 and Fig. 5 sectional views of an engine braking device according to a second embodiment of the invention; and Fig. 6 and Fig. 7 sectional views of an engine braking device according to a third embodiment of the invention. Detailed description of the drawing

[0031] Out of Fig. Figure 1 shows a perspective view of part of a valve train 1 of an internal combustion engine. The valve train 1 is designed for use in an internal combustion engine with three cylinders, with each cylinder in the valve train 1 being assigned four gas exchange valves 2, two of which are inlet valves 3 and two of which are exhaust valves 4.

[0032] Lifting movements of the intake valves 3 assigned to the individual cylinders are initiated in this case via a cam follower 5, which is a rocker arm. Likewise, lifting movements of the exhaust valves 4 of the individual cylinders are also induced via a cam follower 6, which is also designed as a rocker arm and is pivotably mounted about a pivot axis 7. A pivotable mounting of the cam follower 5 is also provided on the pivot axis 7.

[0033] In a manner known in principle to the person skilled in the art, the cam followers 5 and 6 are each provided at one end with a lifting cam of a - in this case in Fig. 1 - valve camshaft of the valve train 1. The individual lifting cam has at least one actuating elevation, by means of which a corresponding tilting movement of the respective cam follower 5 or 6 about the pivot axis 7 is caused, which of the respective cam followers 5 or 6, respectively, converts at an opposite end into corresponding lifting movements of the intake valve 3 or the exhaust valve 4 via an intermediate valve bridge 8 - in this case only visible in the case of the exhaust valves 4.

[0034] Each of the cylinders in the valve train 1 is also assigned an engine braking device 9, which is designed according to a preferred embodiment of the invention and, upon activation, can be used to perform a decompression braking function on the respective cylinder. For this purpose, in a manner known in principle to those skilled in the art, upon activation of the respective decompression braking function on the respective cylinder, one of the exhaust valves 4 is specifically opened. This opening is brought about by a lever-shaped cam follower 10 assigned to the respective cylinder.

[0035] As in Fig. 1 and also in the Fig. 2 and Fig. 3, which shows sectional views of the valve train 1 in the area of ​​the engine braking device 9, the respective cam follower 10 of the respective engine braking device 9 is designed as a brake rocker arm 11, which is also pivotably mounted about the pivot axis 7 and, in the valve train 1, is in contact with an associated lifting cam of the valve camshaft on a roller 12. The contact between the respective cam follower 10 and the associated lifting cam is permanently maintained by means of a lost motion spring 13.

[0036] At an end of the cam follower 10 opposite to the roller 12 and eccentrically to the pivot axis 7, the cam follower 10 carries an adjusting screw 14 and a piston 15, which in particular in Fig. 3. The adjusting screw 14 is guided at the end of the cam follower 10 through a passage 16 in the cam follower 10, wherein this passage 16 is formed by a guide bore 17 formed on the side of the exhaust valve 4 and a through bore 18 adjoining this guide bore 17. A connecting line 19 also runs within the cam follower 10, connecting the pivot axis 7 to the guide bore 17.

[0037] The adjusting screw 14 is supported by a nut 20 on a side of the cam follower 10 facing away from the exhaust valve 4. The piston 15 is cup-shaped and is slidably guided on an outer circumference 21 in the guide bore 17 of the cam follower 10, with a leakage gap—not visible here—also being defined between the outer circumference 21 of the piston 15 and the guide bore 17.

[0038] As particularly in Fig. 3, the piston 15, the adjusting screw 14 and the guide bore 17 of the cam follower 10 together define a pressure chamber 22, into which the connecting line 19 also opens. The adjusting screw 14 is also provided with a circumferential collar 23, which is designed on the adjusting screw 14 in the direction of the end held by the nut 20. A spring element 24 is supported on this collar 23, which is also supported with an opposite end on a disk 25. The disk 25 is held on the piston 15 by a retaining ring 26. As a result, the spring element 24 preloads the piston 15 into a basic position, which in the Fig. 2 and Fig. 3 and in which the piston 15 rests with its bottom against an end face of the adjusting screw 14. In this basic position, the piston 15 does not come into contact with the associated exhaust valve 4 during the tilting movement of the cam follower, thereby realizing a first switching state of the engine braking device 9.

[0039] A blind bore 27 is also provided in the pivot axis 7, which is designed to overlap the cam follower 10 along the pivot axis 7 and is permanently connected to the connecting line 19. A check valve 28 is accommodated in the blind bore 27, which is arranged in the blind bore 27 between the connection to the connecting line 19 and an opening 29 of a supply line 30. The supply line 30 runs axially within the pivot axis 7 and can be pressurized with hydraulic fluid, in particular oil, in a targeted manner.

[0040] The check valve 28 comprises a valve body 31, which is designed as a ball and for which a valve seat 32 is formed by a housing 33 of the check valve 28 on the side of the orifice 29. The housing 33 is pressed into the blind bore 27, wherein the check valve 28 has a spring element 34 located between the orifice 29 and the valve body 31, which spring element 34 is designed as a helical spring and preloads the valve body 31 into a position in which the valve body 31 is moved out of the valve seat 32.

[0041] To activate a decompression brake function for the respective cylinder, the supply line 30 is pressurized, with the check valve 28 also enabling pressurization of the connecting line 19 and thus the pressure chamber 22. As a result, the piston 15 is displaced, counter to the spring element 24, from its basic position into a contact position in which the piston 15 is pushed out of the guide bore 17 relative to the cam follower 10 to such an extent that contact with the associated exhaust valve 4 now occurs during the tilting movement of the cam follower 10. The contact position of the piston 15 is also defined by a mechanical stop, which is realized by contact of the disc 25 with a shoulder 35 on the adjusting screw 14.

[0042] When the piston 15 in its contact position makes frontal contact with the associated outlet valve 4, the check valve 28 prevents hydraulic fluid from flowing back from the pressure chamber 22 into the supply line 30. This prevents the piston 15 from being pushed back towards the home position, so that the engine brake device 9 subsequently converts a cam lift of the associated lifting cam into a corresponding lifting movement of the outlet valve 4, thereby realizing the decompression brake function in the respective cylinder.

[0043] If the pressure supply to the supply line 30 is now interrupted to end the decompression brake function, the pressure in the connecting line 19 and the pressure chamber 22 is also reduced, since, apart from contact between the piston 15 and the associated outlet valve 4, the valve body 31 of the check valve 28 is then lifted out of the valve seat 32 via the spring element 34. Due to this pressure reduction in the pressure chamber 22, the spring element 24 then ensures that the piston 15 is pushed back towards its basic position, wherein a spring stiffness of the spring element 24 is coordinated with a spring stiffness of the spring element 34 in such a way that this pushing back does not result in a renewed closing of the check valve 28, but rather a backflow from the pressure chamber 22 via the connecting line 19 into the supply line 30 is permitted.When the bottom of the piston 15 hits the front side of the adjusting screw 14, the piston 15 has then returned to its basic position.

[0044] Furthermore, the Fig. 4 and Fig. 5 sectional views of an engine braking device 36, which is realized according to a second embodiment of the invention and alternatively to the engine braking device 9 in the valve train 1 from Fig. 1 can be used. The engine braking device 36 largely corresponds to the engine braking device 9 from the Fig. 2 and Fig. 3, with the difference that the check valve 28 is now not accommodated in the pivot axis 7, but is located in a blind hole 37, which is designed in a cam follower 38 of the engine braking device 36. The cam follower 38 corresponds largely to the cam follower 10 of the engine braking device 9 from the Fig. 2 and Fig. 3, wherein the cam follower 38 is now provided on a side facing away from the exhaust valve 4 with a shoulder 39 into which the blind hole 37 is introduced and which, with respect to the piston 15 guided in the cam follower 38, is located on a side of the piston 15 facing the pivot axis 7

[0045] In the blind hole 37, on the one hand, a connecting line 40 opens on a first side of the check valve 28, which in an analogous manner to the variant according to the Fig. 2 and Fig. 3 in the cam follower 38 leading to the pressure chamber 22. On a side of the check valve 28 opposite the connecting line 40, the blind hole 37 is also connected in an analogous manner to the supply line of the pivot axis 7 - not visible here. Furthermore, the design option according to the Fig. 4 and Fig. 5 of the variant according to the Fig. 2 and Fig. 3, so that reference is made to what has been described in this regard.

[0046] Finally, the Fig. 6 and Fig. 7 show sectional views of an engine braking device 41 according to a third embodiment of the invention. This engine braking device 41 largely corresponds to the engine braking device 9 according to the Fig. 2 and Fig. 3 and can also be used as an alternative to the engine brake device 9 in the valve train 1 from Fig. 1 apply.

[0047] What is different now is that the check valve 28 is accommodated in a blind hole 42, which is introduced into the cam follower 10 and thereby transversely penetrates the guide bore 17 and thus also the pressure chamber 22. The check valve 28 is located between the pressure chamber 22 and a connecting line 43, which is now continuously connected to the supply line running along the pivot axis 7 - not shown here. Thus, the check valve 28 is also located laterally to the piston 15 on a side of the piston 15 facing the pivot axis 7. Otherwise, the embodiment according to the Fig. 6 and Fig. 7 of the variant according to the Fig. 2 and Fig. 3, so that reference is made to what has been described in this regard. List of reference symbols 1 valve train 2 gas exchange valves 3 intake valves 4 exhaust valves 5 cam followers 6 cam followers 7 Swivel axis 8 valve bridge 9 Engine braking device 10 cam followers 11 Brake rocker arm 12 roller 13 Lost Motion Spring 14 Adjusting screw 15 pistons 16 passage 17 Guide hole 18 through hole 19 connecting line 20 mother 21 Outer circumference 22 Printing room 23 Bund 24 spring element 25 slices 26 Retaining ring 27 Blind hole drilling 28 Check valve 29 Mouth 30 supply line 31 valve body 32 valve seat 33 housings 34 spring element 35 paragraph 36 Engine braking device 37 Blind hole drilling 38 cam followers 39 Approach 40 connecting line 41 Engine braking device 42 blind hole drilling 43 connecting line QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2023 / 247069 A1

[0004]

Claims

[1] Engine braking device (9; 36; 41) for a valve train (1) of an internal combustion engine, comprising a lever-shaped cam follower (10; 38) which is pivotally mounted about a pivot axis (7) and which carries eccentrically thereto a piston (15) which is displaceably guided between a basic position and a contact position, wherein the piston (15) can be transferred from the basic position into the contact position by pressurizing a pressure chamber (22) from a supply line (30), which contact position is selected for establishing contact between the piston (15) and a gas exchange valve (4) or decompression valve in the valve train (1), and wherein a check valve (28) is also provided which is arranged between the pressure chamber (22) and the supply line (30) and is prestressed into an open state, characterized by that the check valve (28) is arranged eccentrically to the piston (15). [2] Engine braking device (9; 36; 41) according to claim 1, characterized by that the check valve (28) is arranged laterally offset to the piston (15) on a side of the piston (15) facing the pivot axis (7). [3] Engine braking device (36) according to claim 1 or 2, characterized by in that the check valve (28) is integrated into the cam follower (10; 38) and is accommodated in a blind bore (37) which, in the case of the cam follower (38), is introduced into a projection (39) which projects on the cam follower (38) beyond a surface facing away from the gas exchange valve (4) or decompression valve, a connection to the supply line (30) being established in the blind bore (37) on a first side of the check valve (28) and a connecting line (40) opening out on a second side of the check valve (28) opposite to the first side, which connecting line connects the blind bore (37) to the pressure chamber (22). [4] Engine braking device (41) according to claim 1 or 2, characterized byin that the check valve (28) is integrated into the cam follower (10; 38) and is accommodated in a blind hole (42) which is introduced into the cam follower (10) so as to penetrate transversely through the pressure chamber (22), a connection to the supply line (30) being established in the blind hole (42) on a side of the check valve (28) facing away from the pressure chamber (22). [5] Engine braking device (9) according to claim 1 or 2, characterized by in that the check valve (28) is accommodated in a blind hole (27) which is introduced into the pivot axis (7) at the level of the cam follower (10), wherein the supply line (30) opens into the blind hole (27) on a first side of the check valve (28) and a connection is made to a connecting line (19) on a second side of the check valve (28) opposite to the first side, which connects the blind hole (27) to the pressure chamber (22). [6] Engine braking device (9; 36; 41) according to one of the preceding claims, characterized by that the piston (15) is guided on an outer circumference (21) in a guide bore (17) of a surrounding component, which is fixed on the cam follower side, so as to be displaceable between the basic position and the contact position. [7] Engine braking device (9; 36; 41) according to claim 5, characterized by that the guide bore (17) is formed in the cam follower (10; 38). [8] Engine braking device (9; 36; 41) according to one of the preceding claims, characterized by in that the check valve (28) has a valve body (31) which is prestressed into a position in which the valve body (31) moves out of a valve seat (32) provided on the side of the supply line (30), thereby representing the open state of the check valve (28). [9] Engine braking device (9; 36; 41) according to claim 8, characterized bythat the preload of the valve body (31) is carried out via a spring element (34) which is supported on the one hand on the valve body (31) and on the other hand by an opening of the supply line (30). [10] Valve train (1) for an internal combustion engine, comprising at least one engine braking device (9; 36; 41) according to one or more of claims 1 to 9.

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