Engine brake device for valve drive of internal combustion engine

Abstract

The invention relates to an engine brake device for a valve drive of an internal combustion engine, comprising a lever-type cam follower which is mounted so as to be rotatable about a pivot axis and which carries a piston eccentrically with respect to the pivot axis, said piston being movable between a starting position and a contact position, the piston is moved from an initial position to a contact position by the pressure chamber from the action of pressure in the supply line, the contact position being used to establish contact of the piston with a gas exchange valve or a pressure relief valve in the valve drive. Furthermore, a check valve is provided, which is located between the pressure chamber and the supply line and is preloaded in the open state, the check valve being arranged eccentrically with respect to the piston.

Description

Technical Field

[0001] The present invention relates to an engine brake device for a valve train of an internal combustion engine. The device includes a lever-type cam follower, which is rotatably supported about a pivot axis and carries a piston eccentrically relative to the pivot axis. The piston is slidable between a basic position and a contact position. The piston can be moved from the basic position to the contact position by pressure from a pressure chamber of a supply line. The contact position is designed to bring the piston into contact with a gas exchange valve or a decompression valve in the valve train. Furthermore, a check valve is provided, which is arranged between the pressure chamber and the supply line and is prestressed to an open state. The present invention also relates to a valve train for an internal combustion engine, comprising at least one of the above-described engine brake devices. Background Art

[0002] In the commercial vehicle sector, continuous braking devices are known. These devices enable wear-free braking of the corresponding commercial vehicle, for example, preventing excessive wear and overheating of the brake system during extended driving on slopes. In addition to continuous braking devices in the form of retarders, engine braking devices are also frequently used to selectively increase the drag torque of the commercial vehicle's internal combustion engine. A common approach involves providing a throttle valve in the engine's exhaust line, which selectively generates backpressure, thereby making it more difficult for the engine's individual pistons to expel gas into the exhaust system, thereby generating higher drag torque. Alternatively, and often in addition, a so-called decompression braking function is often implemented. Within this function, at the end of the compression stroke in the engine's valve train, one of the exhaust valves of each cylinder, or a separate decompression valve, is selectively opened, typically by the engine braking device. This results in less work being done during the subsequent expansion process due to the targeted decompression, thus achieving braking.

[0003] In some cases, the engine brake system consists of a hydraulic brake actuator and a cam follower supporting it. When the decompression brake function is activated, a piston is usually hydraulically shifted at the brake actuator into a position in which the movement introduced in the cam follower can be converted by the piston into a targeted opening of the corresponding valve at the end of the compression stroke.

[0004] WO 2023 / 247069 A1 discloses an engine brake device in which a lever-type cam follower is equipped with a hydraulic brake operating device. The cam follower is designed as a swing arm, pivotably supported about a pivot in the valve train of an internal combustion engine. The brake operating device is supported at one end of the swing arm, eccentrically relative to the pivot. The brake operating device comprises a housing fixed to one side of the cam follower, within which a piston is slidably guided. The piston is preloaded into a base position within the housing. From this base position, it can be moved by pressure from a pressure chamber in a supply line into a contact position, in which the lifting motion introduced into the cam follower can be transmitted to an exhaust valve via the piston. Furthermore, a movable pin is housed within the housing and preloaded into a position by a spring element. In this position, the pin holds the check valve of the brake operating device in an open position, in which the valve body of the check valve is displaced from its valve seat. Here, the non-return valve is arranged coaxially with the piston in the cam follower.

[0005] When pressure is applied to the supply line to activate the decompression braking function, the pin is displaced against the force of the spring element and subsequently no longer acts on the valve body of the check valve. At this point, the check valve still allows pressure to be applied to the pressure chamber, causing the piston to move into the contact position. Subsequently, when the piston contacts the exhaust valve, the check valve prevents hydraulic fluid from escaping the pressure chamber. Conversely, when the decompression braking function ends, the drop in pressure in the supply line causes the spring element to return the pin to a position in which it displaces the valve body from its seat. This allows hydraulic fluid to flow out of the pressure chamber, and the piston returns to its normal position due to the preload force.

[0006] Based on the prior art described above, the technical problem to be solved by the present invention is to provide an engine braking device having a simpler structure. Summary of the Invention

[0007] This technical problem is solved by the preamble of claim 1 in combination with the characterizing features of claim 1. The following dependent claims each provide advantageous developments of the invention. A valve train in which at least one engine brake device according to the invention is provided is also the subject of claim 10.

[0008] According to the present invention, an engine brake device includes a lever-type cam follower that is rotatably supported about a pivot axis and carries a piston eccentrically relative to the pivot axis. The piston is movable between a base position and a contact position. The piston can be moved from the base position to a contact position by pressure from a pressure chamber in a supply line. The contact position is configured to bring the piston into contact with a gas exchange valve or a decompression valve in a valve drive mechanism. Furthermore, a check valve is provided, which is disposed between the pressure chamber and the supply line and is preloaded in an open position.

[0009] For the purposes of the present invention, a "cam follower" is generally understood to mean a transmission element by which a corresponding drive lobe of an associated cam can be converted into a corresponding lift of one or more gas exchange valves and / or an additional decompression valve. The cam follower of the engine brake device according to the present invention is preferably a braking cam follower, which serves solely to implement a corresponding decompression braking function in the valve train of an internal combustion engine. However, within the scope of the present invention, the cam follower of the engine brake device according to the present invention can also be designed to perform the gas exchange operations required for normal operation of the internal combustion engine, in addition to the decompression braking function.

[0010] Particularly preferably, the cam follower is designed as a swing arm, which is pivotally mounted in the middle of the lever-type cam follower, while the piston of the engine brake is disposed at one end of the cam follower, and a contact region for inducing the drive movement is provided at the opposite end of the cam follower. Alternatively, the cam follower can also be a pivoting arm, in which case it is pivotally mounted, in particular, at one end of the cam follower, carries the piston of the engine brake at the opposite end, and a contact region for inducing the drive movement is provided in a central section located in the middle of the cam follower. In both cases, a roller is rotatably mounted in the respective contact region of the cam follower, and when the engine brake is installed in the valve train of the internal combustion engine, the roller comes into contact with the associated cam.

[0011] The engine brake device comprises a movably guided piston, which is supported eccentrically relative to its pivot axis by a cam follower. The piston is particularly cup-shaped, meaning that its cross section is at least essentially formed by a hollow cylindrical section and a base section that closes the hollow cylindrical section at one end. The piston can be moved from a basic position to a contact position by pressure from a pressure chamber, the pressure acting on the pressure chamber being supplied by a supply line. The piston is thus guided so as to be movable between the basic position and the contact position. Preferably, the pressure chamber is delimited by at least one piston-guiding component and the cup-shaped piston.

[0012] In its contact position, the piston preferably projects far enough relative to the cam follower that, when a movement is introduced into the cam follower in the internal combustion engine valve drive, the piston comes into contact with the valve, in particular at the end, and the movement of the cam follower can subsequently be transmitted to the valve. As a result, a corresponding lift movement of the valve is produced. In contrast, in its base position, the piston is retracted far enough that no contact with the valve occurs.

[0013] Preferably, both the base position and the contact position of the piston are defined by mechanical stops, wherein each of these stops is formed in particular by an adjusting screw which is mounted on the cam follower, in particular concentrically with the piston. In the base position, the cup-shaped piston, in particular at its bottom portion, rests against an end face of the adjusting screw, which prevents the piston from being moved back further into the cam follower. The mechanical stop which defines the contact position, on the other hand, is formed in particular by a step of the adjusting screw, and it is further preferred that a disk is fixed to the piston which comes into contact with the step of the adjusting screw when the piston is in the contact position. This ensures that the piston reliably projects to the desired extent relative to the cam follower when it is switched to its contact position.

[0014] Preferably, the adjusting screw passes through a through-hole in the cam follower and its end facing away from the piston projects out of the cam follower, wherein the adjusting screw is fixed to the cam follower at this end, in particular by means of a nut. By means of this nut, the relative position of the adjusting screw relative to the piston, and thus also the mechanical stop, can be adjusted.

[0015] In the engine brake according to the application, a check valve is also provided, which has a valve body, wherein the valve body is preferably a ball. The check valve is pre-tensioned into an open state in which it is in a position in which fluid exchange between the pressure chamber and the supply line is possible. In contrast, when the check valve is switched into a closed state, it separates the pressure chamber and the supply line from one another.

[0016] The application now has the technical teaching that the check valve is arranged in an eccentric position relative to the piston. In other words, the check valve is arranged offset relative to the piston.

[0017] The design of such an engine brake has the advantage that, as a result of this offset arrangement of the check valve relative to the piston, the cam follower can have a simpler structure compared to the case of a concentric arrangement of the check valve and the piston. As a result, a simpler structure of the engine brake as a whole can also be achieved.

[0018] According to one embodiment of the present invention, the check valve is arranged at a position laterally offset relative to the piston and located on the side of the piston facing the pivot. Thus, a suitable arrangement of the check valve can be achieved.

[0019] As an alternative, and preferably in addition to the above-described embodiment, the nonreturn valve is integrated into the cam follower and accommodated in a blind hole, which is provided in a projection of the cam follower and projects from a surface of the cam follower facing away from the gas exchange valve or the decompression valve. In the blind hole, a first side of the nonreturn valve is connected to the supply line, and a second side of the nonreturn valve, opposite the first side, opens into a connecting line that connects the blind hole to the pressure chamber.

[0020] In another alternative embodiment of the present invention, the non-return valve is integrated in the cam follower and accommodated in a blind hole that extends transversely through the pressure chamber in the cam follower. In the blind hole, a connection is established with the supply line on the side of the non-return valve facing away from the pressure chamber.

[0021] As an alternative, the non-return valve is accommodated in a blind hole, which is provided in the pivot shaft at the height of the cam follower. The supply line opens into the blind hole on a first side of the non-return valve and is connected to a connecting line on a second side of the non-return valve, opposite the first side, which connects the blind hole to the pressure chamber.

[0022] According to another embodiment of the present invention, the piston is displaceably guided on its outer circumference between a basic position and a contact position via a guide hole in a surrounding component, wherein the surrounding component is fixed to one side of the cam follower. This advantageously achieves suitable guidance of the piston. The surrounding component is fixed to the cam follower, that is, during operation of the internal combustion engine valve train, the surrounding component is fixedly connected to the cam follower and does not move.

[0023] As a further improvement to the above embodiment, a guide hole is provided in the cam follower. In this case, the piston is movably guided directly within the cam follower at its outer periphery because the guide hole is machined into the lever-type cam follower. However, within the scope of the present invention, it is also conceivable to provide the guide hole in a separate component that is fixed to one side of the cam follower when the engine brake device is installed in the valve train of an internal combustion engine. For example, this component could be an adjusting screw that forms a piston stop.

[0024] According to another possible embodiment of the present invention, the check valve includes a valve body that is prestressed into a position in which the valve body moves out of a valve seat provided on the supply line side, thereby assuming the open state of the check valve. In particular, the prestressing of the valve body is achieved by a spring element, one end of which is supported on the valve body and the other end on the open side of the supply line. This allows for compact prestressing of the check valve in the open state.

[0025] As a further refinement of the present invention, the piston is preloaded into a basic position. This has the advantage that when the pressure chamber is not under pressure, the piston returns to its basic position. Thus, with the engine brake device according to the present invention, a decompression braking function can be achieved by applying pressure to the pressure chamber, followed by the piston moving from its basic position to its contact position. To terminate the decompression braking function, the application of pressure to the pressure chamber must then be stopped, at which point the piston returns to its basic position due to its preload.

[0026] For reliable engine braking, the characteristic curve of the preload spring for the check valve in its open state must match the characteristic curve of the spring that preloads the piston into its normal position. This is because once the piston has successfully moved to its contact position, the pressure supply to the supply line ends, causing the check valve to switch back to its normal position, and the piston to move back toward its normal position due to its preload force. If this process generates excessive pressure in the pressure chamber, this will cause the check valve to close again, thus preventing the piston from moving back.

[0027] Preferably, the piston is preloaded to the basic position by a spring element, so that the preload of the piston to its basic position can be reliably achieved. As mentioned above, in order to make the engine brake device operate reliably, the spring characteristic curve of this spring element needs to match the spring characteristic curve of the check valve preload.

[0028] If the engine brake device according to the present invention is also provided with an adjusting screw, the spring element that preloads the piston is supported at one end on a flange provided on the adjusting screw and at the other end on the side of the piston. If one of the mechanical stops of the piston is also formed by a disk fixed to the piston, the spring element can be supported on the side of the piston on this disk.

[0029] The subject matter of the present invention also includes a valve train for an internal combustion engine, wherein at least one engine brake device according to one or more of the above-described embodiments is arranged in the valve train. With at least one engine brake device according to the present invention, a decompression braking function can be easily implemented on each cylinder of the internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] An advantageous embodiment of the present invention is shown in the accompanying drawings and will be described in detail below. The drawings show:

[0031] Figure 1 is a perspective view of a portion of a valve actuation mechanism of an internal combustion engine;

[0032] Figure 2 and Figure 3 According to the first embodiment of the present invention Figure 1 A cross-sectional view of the valve drive mechanism in the area of ​​the engine brake;

[0033] Figure 4 and Figure 5 is a cross-sectional view of an engine brake device according to a second possible embodiment of the present invention; and

[0034] Figure 6 and Figure 7 is a cross-sectional view of an engine brake device according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0035] Figure 1 The figure shows a perspective view of a portion of a valve train 1 of an internal combustion engine. The valve train 1 is designed for an internal combustion engine having three cylinders, wherein each cylinder is assigned four gas exchange valves 2 in the valve train 1, wherein each cylinder is assigned two intake valves 3 and two exhaust valves 4.

[0036] The lifting movement of the intake valve 3 assigned to each cylinder is guided by a cam follower 5, which is a swing arm. Similarly, the lifting movement of the exhaust valve 4 of each cylinder is generated by a cam follower 6, which is also designed as a swing arm and is mounted so as to be pivotable about a pivot 7. A pivotable support for the cam follower 5 is also provided on the pivot 7.

[0037] As is well known to those skilled in the art, one end of the cam followers 5 and 6 is respectively connected to the valve camshaft ( Figure 1 Each cam has at least one driving projection, which causes the corresponding cam follower 5 or 6 to generate a corresponding oscillating motion about a pivot 7. This oscillating motion is converted by the corresponding cam follower 5 or 6 at its opposite end through a valve bridge 8 located in the middle (only visible when the exhaust valve 4 is in operation) to a corresponding lifting motion of the intake valve 3 or the exhaust valve 4.

[0038] In valve train 1, each cylinder is also equipped with an engine brake 9, configured according to a preferred embodiment of the present invention. Upon activation, the engine brake performs a decompression braking function on the corresponding cylinder. To this end, as is well known to those skilled in the art, upon activation of the decompression braking function for the corresponding cylinder, one of the exhaust valves 4 is selectively opened. This opening is achieved via a lever-type cam follower 10 associated with each cylinder.

[0039] like Figure 1 as well as Figure 2 and Figure 3 As shown in these sectional views of the valve train 1 in the area of ​​the engine brake device 9, the respective cam follower 10 of each engine brake device 9 is designed as a brake swing arm 11, which is also mounted so as to be pivotable about a pivot axis 7. In the valve train 1, the brake swing arm 11 contacts the associated cam of the valve camshaft via a roller 12. The contact between the respective cam follower 10 and the associated cam is always maintained by a lost motion spring 13.

[0040] At the end of the cam follower 10 opposite the roller 12 and eccentrically relative to the pivot 7, the cam follower 10 carries an adjusting screw 14 and a piston 15, in particular Figure 3 They can be seen in the figure. The adjusting screw 14 extends through a channel 16 in the cam follower 10 to the end of the cam follower 10. The channel 16 is formed by a guide hole 17 located on the side of the exhaust valve 4 and a through hole 18 connected to the guide hole 17. In addition, a connecting pipe 19 is provided inside the cam follower 10, which connects the pivot 7 to the guide hole 17.

[0041] The adjusting screw 14 is supported by a nut 20 on the side of the cam follower 10 facing away from the exhaust valve 4. The piston 15 is cup-shaped, and its outer periphery 21 is slidably guided in the guide hole 17 of the cam follower 10, wherein a leakage gap (not shown at present) is also defined between the outer periphery 21 of the piston 15 and the guide hole 17.

[0042] Especially Figure 3 As shown, the piston 15, the adjusting screw 14 and the guide hole 17 of the cam follower 10 together define a pressure chamber 22, into which the connecting line 19 also leads. In addition, the adjusting screw 14 is provided with a circumferential flange 23, which is arranged on the adjusting screw 14 toward the end fixed by the nut 20. A spring element 24 is supported on this flange 23, and the other end of the spring element 24 is supported on a disk 25 opposite to the flange. The disk 25 is fixed to the piston 15 by a retaining ring 26. Therefore, the spring element 24 preloads the piston 15 to the position shown in FIG. Figure 2 and Figure 3The basic position shown is shown in which the bottom of the piston 15 rests on the 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 oscillation of the cam follower, thereby achieving the first operating state of the engine brake device 9.

[0043] Furthermore, a blind hole 27 is formed in the pivot shaft 7, which is arranged along the pivot shaft 7 and overlaps with the cam follower 10 and is always connected to the connecting line 19. A non-return valve 28 is accommodated in the blind hole 27 and is arranged in the blind hole 27 between the connection to the connecting line 19 and an opening 29 of a supply line 30. The supply line 30 extends axially within the pivot shaft 7 and can be supplied with hydraulic fluid, in particular oil, in a targeted manner to exert pressure.

[0044] The non-return valve 28 comprises a valve body 31 which is designed as a ball and, on the side of the opening 29, a valve seat 32 is formed by a housing 33 of the non-return valve 28. The housing 33 is pressed into the blind hole 27, wherein the non-return valve 28 has a spring element 34 which is located between the opening 29 and the valve body 31 and is designed as a coil spring and which preloads the valve body 31 into a position in which the valve body 31 moves out of the valve seat 32.

[0045] To activate the pressure-reducing brake function on the corresponding cylinder, pressure is applied to the supply line 30, during which the nonreturn valve 28 allows pressure to act on the connecting line 19 and the pressure chamber 22. As a result, the piston 15 is displaced from its rest position against the spring element 24 into the contact position. In this contact position, the piston 15 has moved sufficiently far out of the guide bore 17 relative to the cam follower 10 so that it can now contact the associated exhaust valve 4 during the oscillation of the cam follower 10. The contact position of the piston 15 is also defined by a mechanical stop, which is achieved by the contact of the disk 25 with the step 35 on the adjusting screw 14.

[0046] When the piston 15 in the contact position contacts the associated exhaust valve 4 at its end, the check valve 28 prevents the hydraulic fluid from flowing back from the pressure chamber 22 into the supply line 30. As a result, the piston 15 is prevented from moving back toward the basic position, so that the engine brake device 9 then converts the cam lobe of the associated cam into a corresponding lifting movement of the exhaust valve 4, thereby realizing a decompression braking function on the corresponding cylinder.

[0047] If the pressure supply to the supply line 30 is now interrupted in order to terminate the pressure reduction brake function, the pressure in the connecting line 19 and the pressure chamber 22 also decreases because, without the piston 15 in contact with the associated exhaust valve 4, the valve body 31 of the non-return valve 28 is then lifted from the valve seat 32 by the spring element 34. Due to the pressure drop in the pressure chamber 22, the spring element 24 then moves the piston 15 back toward its basic position, the spring stiffness of the spring element 24 being matched to the spring stiffness of the spring element 34 so that during this return movement, the non-return valve 28 does not close again, but allows the fluid in the pressure chamber 22 to flow back into the supply line 30 via the connecting line 19. The piston 15 returns to its basic position when the bottom of the piston 15 strikes the end face of the adjusting screw 14.

[0048] also, Figure 4 and Figure 5 A cross-sectional view of an engine brake device 36 is shown, which is designed according to a second embodiment of the present invention and can replace Figure 1 The engine brake device 9 of the valve drive mechanism 1 is used. Here, the engine brake device 36 is largely Figure 2 and Figure 3 The engine brake device 9 in FIG. 1 is identical, except that the check valve 28 is now not mounted in the pivot 7 but in a blind hole 37 which is machined in the cam follower 38 of the engine brake device 36. The cam follower 38 is largely identical to the Figure 2 and Figure 3 The cam follower 10 of the engine brake device 9 is consistent, wherein the cam follower 38 is now provided with a protrusion 39 on the side facing away from the exhaust valve 4, in which a blind hole 37 is machined and, relative to the piston 15 guided in the cam follower 38, the protrusion is located on the side of the piston 15 facing the pivot 7.

[0049] In the blind hole 37, on the one hand, a connecting line 40 opens on the side of the non-return valve 28, which is similar to the Figure 2 and Figure 3 The embodiment shown extends in the cam follower 38 and opens into the pressure chamber 22. On the side of the non-return valve 28 opposite the connecting line 40, the blind hole 37 is also connected in a similar manner to the supply line of the pivot shaft 7 (not shown at the moment). Figure 4 and Figure 5 The embodiment shown is also similar in other respects to Figure 2 and Figure 3 The embodiments shown are identical, so reference is made to the description thereof.

[0050] Finally, from Figure 6 and Figure 7A cross-sectional view of an engine brake device 41 according to a third embodiment of the invention can also be seen in FIG. Figure 2 and Figure 3 The engine brake device 9 is consistent with and can also replace Figure 1 The engine brake device 9 of the valve drive mechanism 1 is used.

[0051] The difference is that the non-return valve 28 is accommodated in a blind hole 42 which is machined into the cam follower 10 and which extends transversely through the guide hole 17 and thus also through the pressure chamber 22. The non-return valve 28 is located between the pressure chamber 22 and the connecting line 43, which is now always connected to the supply line (not shown at present) extending in the pivot 7. Therefore, in this case, the non-return valve 28 is also located on the side of the piston 15, on the side of the piston 15 facing the pivot 7. In addition, Figure 6 and Figure 7 The embodiment shown is similar to Figure 2 and Figure 3 The embodiments shown are identical, so reference is made to the description thereof.

[0052] Reference Signs List

[0053] 1 Valve drive mechanism

[0054] 2 ventilation doors

[0055] 3 Intake valves

[0056] 4 exhaust valves

[0057] 5 Cam follower

[0058] 6 Cam followers

[0059] 7 Pivot

[0060] 8 valve bridge

[0061] 9 Engine brake

[0062] 10 Cam follower

[0063] 11 brake swing arm

[0064] 12 Rollers

[0065] 13 Lost motion spring

[0066] 14 Adjusting screw

[0067] 15 piston

[0068] 16 through holes

[0069] 17 guide holes

[0070] 18 through holes

[0071] 19 Connecting pipes

[0072] 20 Nut

[0073] 21 Periphery

[0074] 22 pressure chamber

[0075] 23 flange

[0076] 24 Spring elements

[0077] 25 plates

[0078] 26 Snap ring

[0079] 27 blind holes

[0080] 28 Check valve

[0081] 29 Opening

[0082] 30 Supply lines

[0083] 31 Valve body

[0084] 32 valve seat

[0085] 33 housing

[0086] 34 Spring element

[0087] 35 steps

[0088] 36 Engine brake

[0089] 37 blind holes

[0090] 38 Cam follower

[0091] 39 bulge

[0092] 40 Connecting pipes

[0093] 41 Engine brake

[0094] 42 blind holes

[0095] 43 Connecting pipes

Claims

1. An engine brake device (9; 36; 41) for a valve train (1) of an internal combustion engine, comprising a lever-type cam follower (10; 38) which is rotatably supported about a pivot (7) and carries a piston (15) eccentrically relative to the pivot, the piston being movable between a base position and a contact position, wherein: The piston (15) can be moved from the basic position to the contact position by the pressure of the pressure chamber (22) from the supply line (30), and the contact position is set to make the piston (15) contact with the gas exchange valve (4) or the decompression valve in the valve drive mechanism (1), 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, characterized in that the check valve (28) is arranged in a position eccentric to the piston (15).

2. The engine braking device (9; 36; 41) according to claim 1, characterized in that The check valve (28) is arranged at a position laterally offset relative to the piston (15) and is located on a side of the piston (15) facing the pivot (7).

3. The engine braking device (36) according to claim 1 or 2, characterized in that The non-return valve (28) is integrated in the cam follower (10; 38) and is accommodated in a blind hole (37), wherein the blind hole is provided in a projection (39) in the cam follower (38), the projection protruding from a surface of the cam follower (38) facing away from the gas exchange valve (4) or the decompression valve, wherein, in the blind hole (37), a first side of the non-return valve (28) is connected to the supply line (30), and a second side of the non-return valve (28) opposite to the first side leads to a connecting line (40), which connects the blind hole (37) to the pressure chamber (22).

4. The engine braking device (41) according to claim 1 or 2, characterized in that The non-return valve (28) is integrated in the cam follower (10; 38) and is accommodated in a blind hole (42) which extends transversely through the pressure chamber (22) in the cam follower (10), wherein in the blind hole (42), the non-return valve (28) is connected to the supply line (30) on the side facing the pressure chamber (22).

5. The engine braking device (9) according to claim 1 or 2, characterized in that The non-return valve (28) is accommodated in a blind hole (27) which is provided in the pivot (7) at a height of the cam follower (10), wherein a first side of the non-return valve (28) opens into the supply line (30) in the blind hole (27) and a second side of the non-return valve (28) opposite the first side is connected to a connecting line (19) which connects the blind hole (27) to the pressure chamber (22).

6. The engine brake device (9; 36; 41) according to any one of the preceding claims, characterized in that The piston (15) is slidably guided between the basic position and the contact position in a guide hole (17) of a surrounding member via its outer periphery (21), and the surrounding member is fixed to one side of the cam follower.

7. The engine braking device (9; 36; 41) according to claim 5, characterized in that The guide hole (17) is provided in the cam follower (10; 38).

8. The engine brake device (9; 36; 41) according to any one of the preceding claims, characterized in that The non-return 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 achieving an open state of the non-return valve (28).

9. The engine braking device (9; 36; 41) according to claim 8, characterized in that The pre-stressing of the valve body (31) is achieved by a spring element (34), one end of which is supported on the valve body (31) and the other end is supported on the opening side of the supply line (30).

10. A valve train (1) for an internal combustion engine, comprising at least one engine brake device (9; 36; 41) according to one or more of claims 1 to 9.

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