In particular, the valve train of an internal combustion engine of a motor vehicle and an internal combustion engine of a motor vehicle

Abstract

The invention relates to a valve train (10) for an internal combustion engine, having at least one exhaust valve (12), at least one engine brake rocker arm (16) which can be pivoted about a pivot axis (20), by means of which the exhaust valve (12) can be operated in an engine braking operation of the internal combustion engine by pivoting of the engine brake rocker arm (16), at least one camshaft (26) which has at least one cam (28) which can pivot the engine brake rocker arm (16) about the pivot axis (20), and at least one spring element (44) which presses the engine brake rocker arm (16) against the camshaft (26), wherein the spring element (44) is designed as a leaf spring (50).

Description

Technical Field

[0001] This invention relates to a valve train for an internal combustion engine, particularly for motor vehicles. The invention also relates to an internal combustion engine for motor vehicles. Background Technology

[0002] EP 2 425 105 B1 discloses a system for operating an engine exhaust valve to achieve engine braking. The system includes a rocker arm shaft with a control fluid supply passage and an engine braking rocker arm pivotally mounted on the rocker arm shaft. Additionally, a cam is provided for engine braking operation of the engine braking rocker arm. The system also includes a spring that presses the engine braking rocker arm into contact with the cam. Summary of the Invention

[0003] The objective of this invention is to provide a valve train for an internal combustion engine and an internal combustion engine having such a valve train, enabling particularly advantageous operation in a manner that is both cost-effective and space-efficient.

[0004] This task is accomplished by a valve train and an internal combustion engine having the features described below.

[0005] The first aspect of the invention relates to a valve train for an internal combustion engine, preferably designed as a piston machine or piston engine, particularly for motor vehicles. This means that a motor vehicle, for example designed as an automobile, particularly a truck, includes the internal combustion engine and, consequently, the valve train in its manufactured state, and can be driven by the internal combustion engine. Here, the internal combustion engine has, for example, an engine block that at least partially, particularly directly, defines at least one combustion chamber of the internal combustion engine. For this purpose, the engine block has, for example, at least one cylinder, which is, for example, particularly directly defined by the engine block. The cylinder partially defines the combustion chamber. During the ignition and operation of the internal combustion engine, a combustion process takes place in the combustion chamber. Exhaust gases from the combustion process are discharged from the combustion chamber, for example, through at least one exhaust passage disposed in the combustion chamber. The exhaust passage is, for example, formed or defined by a housing component of the internal combustion engine, i.e., formed within the housing. The housing component is, for example, separately constructed from and connected to the engine block. The housing component can, in particular, be a cylinder head. The engine block is, for example, a crankshaft housing or a cylinder crankcase.

[0006] Here, the valve train has at least one exhaust valve designed as an exhaust valve, preferably disposed in the combustion chamber and, more specifically, in an exhaust duct disposed within the combustion chamber. The exhaust valve is, for example, capable of, particularly translational movement and / or relative to the housing members, between a closed position and at least one open position. In the closed position, for example, the exhaust valve locks the corresponding exhaust duct, thus preventing gas from flowing from the combustion chamber into the exhaust duct. In the open position, the exhaust valve opens the exhaust duct, allowing gas, such as exhaust gas, to flow from the combustion chamber into the exhaust duct via the exhaust valve in the open position.

[0007] Furthermore, the valve train includes at least one engine brake rocker arm pivotable about a pivot axis and disposed on the exhaust valve. With the aid of the engine brake rocker arm, the exhaust valve can be operated by pivoting the engine brake rocker arm during engine braking operation of the internal combustion engine, thereby moving it, in particular, from a closed position to an open position. In other words, during engine braking operation of the internal combustion engine, the exhaust valve is operable or actuated in such a way that the engine brake rocker arm pivots about a pivot axis. During engine braking operation, the internal combustion engine functions as or acts as an engine brake, thereby braking the motor vehicle and / or preventing excessive increases in the vehicle's speed (i.e., the speed at which the vehicle travels along the road). In other words, the internal combustion engine functions as or acts as an engine brake during engine braking operation. Engine braking is preferably designed as a pressure-reducing brake. It is particularly advantageous that the combustion process in the combustion chamber ceases during engine braking operation, so that, for example, during engine braking operation, the gas flowing from the combustion chamber through the open exhaust valve into the exhaust manifold is at least primarily, and especially entirely, air.

[0008] Furthermore, the valve train includes at least one camshaft, which is, for example, rotatable relative to the housing member about an axis of rotation. In particular, it is conceivable that an engine brake rocker arm, also simply referred to as a brake rocker arm or rocker arm, is pivotable relative to the housing member about a pivot axis. Specifically, it is specified that the axis of rotation is spaced apart from and / or extends parallel to the axis of pivot. The camshaft has at least one cam, also referred to as a brake cam. The cam is rotatable relative to the housing member about this axis of rotation. The engine brake rocker arm can be operated by means of the cam, thus making it pivotable about the pivot axis. For this purpose, the engine brake rocker arm, for example, has a follower that, in particular, contacts the cam and rolls and / or slides on the cam, for example, when the camshaft and, consequently, the cam, rotate about the axis of rotation. The cam follower, for example, is a roller, which is held on the rocker arm body, for example, in a manner rotatable relative to the rocker arm body of the engine brake rocker arm about a roller's axis of rotation.

[0009] Furthermore, the valve train includes at least one spring element that presses, preloads, the engine brake rocker arm against the camshaft, and in particular the cam. This specifically refers to the cam follower being pressed against the cam and, consequently, the camshaft by means of the spring element. In other words, the spring element provides spring force to press the engine brake rocker arm against the camshaft, and in particular the cam, thereby keeping the engine brake rocker arm, and especially the cam follower, in particularly direct contact with the camshaft, and in particular the cam.

[0010] To achieve particularly advantageous operation of the valve train and the internal combustion engine as a whole in a cost- and structurally advantageous manner, this invention specifies that the spring element is designed as a leaf spring. In other words, the spring element is a mechanical spring, unlike common solutions, designed as a leaf spring instead of a coil spring. The leaf spring is used to preload the engine brake rocker arm to press or preload it against the camshaft. The spring element allows the engine brake rocker arm to maintain reliable contact with the camshaft, thereby compensating, for example, for errors caused by machining and / or installation. This allows for highly advantageous engine braking operation. Because the spring element is now constructed as a leaf spring according to the invention, it can be manufactured advantageously, but especially cost-effectively, in terms of machining technology, so that the cost of the valve train and, consequently, the internal combustion engine, can be kept very low. Furthermore, the spring element can be installed simply and therefore advantageously in terms of both time and cost. In other words, the machining and installation costs of the valve train can be reduced compared to common solutions, thereby maintaining a low valve train cost. Furthermore, compared to other types of springs such as coil springs, leaf springs have significantly smaller structural space requirements, thus keeping the structural space requirements of the valve train very low. Additionally, compared to other types of springs such as coil springs, leaf springs have simpler manufacturing processes, thereby keeping costs very low.

[0011] To maintain very low costs, leaf springs are ideally designed as punched and / or bent parts, and are thus manufactured by punching and / or bending. This allows the leaf springs themselves to be manufactured simply and advantageously in terms of both time and cost, thereby keeping the cost of the valve train and, consequently, the overall cost of the internal combustion engine very low.

[0012] The exhaust valve mentioned and described above is also referred to as the first exhaust valve, and the engine brake rocker arm mentioned and described above is also referred to as the first engine brake rocker arm. In addition, the cam mentioned and described above is also referred to as the first cam, and the spring mentioned and described above is also referred to as the first spring; therefore, the aforementioned leaf spring is also referred to as the first leaf spring.

[0013] It is particularly advantageous here that the valve train includes a second exhaust valve in addition to the first exhaust valve. The second exhaust valve is preferably located in the second combustion chamber, and the description of the first combustion chamber above and below can be directly applied to the second combustion chamber, and vice versa. Therefore, it is conceivable that the second combustion chamber is at least partially formed by or particularly directly defined by the engine block. It is particularly conceivable here that the second exhaust valve is located in a second exhaust passage provided in addition to the aforementioned exhaust passage, wherein, preferably, the second exhaust passage is formed by or within the aforementioned housing member. Therefore, for example, the description of the first exhaust passage above and below can be directly applied to the second exhaust passage. During the ignition and operation of the internal combustion engine, a combustion process occurs, for example, in the second combustion chamber, thereby generating exhaust gas that can flow from the second combustion chamber into the second exhaust passage. Here, for example, the second exhaust valve can be particularly translationally and / or move relative to the housing member between a second closed position and at least one second open position. In the second closed position, the second exhaust valve locks the second exhaust passage, so no gas can flow from the second combustion chamber into the second exhaust passage. In the second open position, for example, the second exhaust valve opens the second exhaust passage, so gas can then flow from the second combustion chamber into the second exhaust passage through the open second exhaust valve.

[0014] Here, the valve train preferably includes a second engine brake rocker arm pivotable about a pivot axis, particularly relative to the housing component. The description of the first engine brake rocker arm above and below can be directly applied to the second engine brake rocker arm, and vice versa. With the aid of the second engine brake rocker arm, during engine braking operation, the second exhaust valve can be operated by pivoting the second engine brake rocker arm, thereby moving it from a second closed position to a second open position. Preferably, a second engine brake rocker arm is provided as a supplement to the first engine brake rocker arm. The camshaft here has a second cam as a supplement to the first cam. The second cam is at least preferably also rotatable about a rotation axis relative to the engine block or relative to the housing component. With the aid of the second cam, the second engine brake rocker arm can be pivoted about a pivot axis, and the description of the first cam below and above can preferably be applied to the second cam, and vice versa.

[0015] Here, the valve train includes a second mechanical spring that complements the first spring. With the aid of the second spring, the second engine brake rocker arm, and in particular its cam follower, is pressed against the camshaft, particularly the second cam. The description of the first spring above and below can be directly applied to the second spring, and vice versa. To keep the structural space requirements and cost of the valve train very low, it is preferable to design the second spring as a second leaf spring.

[0016] Another embodiment is characterized by these leaf springs, namely the first leaf spring and the second leaf spring, being integrally formed. In other words, it is preferably specified that the first leaf spring and the second leaf spring are constituted by a one-piece spring mechanism or a one-piece spring body. The spring body is preferably designed as a spring sheet, so the spring body can be made of metal, especially metal sheets. This in particular means that the leaf springs are made of the same material and therefore of the same metal material. Since the leaf springs are integrally formed, the following advantages can be achieved: the number of parts in the valve train and thus the cost can be kept very low. In addition, the leaf springs can be installed simultaneously, so that the valve train can be manufactured or installed in a time- and cost-effective manner.

[0017] Common solutions employ a metal base plate and a coil spring fixed thereon for preloading the engine brake rocker arm toward or to the camshaft. Here, each of several, particularly six, engine brake rocker arms uses a separate coil spring, constructed independently of each other and must be securely fastened to the metal base plate to prevent loss via a clamping / screw connection mechanism or a riveting process. This results in a complex installation process, which can now be avoided with this invention. Furthermore, coil springs require more structural space than leaf springs, which can lead to high loads on the spring bases of the respective engine brake rocker arms. This, too, can now be avoided with this invention.

[0018] In another particularly advantageous embodiment of the invention, the leaf springs, namely the first leaf spring and / or the second leaf spring, are made of metallic materials, especially metal sheets. This allows the structural space requirements and cost of the valve train to be kept very low.

[0019] It has been found that it is particularly advantageous that the leaf springs, namely the first leaf spring and / or the second leaf spring, are designed as spring arms / elastic arms extending longitudinally, protruding from the main body, particularly the spring mechanism or spring body, along their longitudinal extension. Thus, the spring arms are elastically held onto the main body. In other words, at least one local area of ​​the spring arm can be elastically deformable or elastically deformable, such that each engine braking rocker arm, namely the first engine braking rocker arm and / or the second engine braking rocker arm, can be pressed against the camshaft, particularly the corresponding cam, in a manner particularly advantageous in terms of structural space and cost.

[0020] To enable cost-effective manufacturing of the valve train, another design of the invention specifies that leaf springs, namely the first leaf spring and / or the second leaf spring, are fixed to the valve train housing by a body. This housing is, for example, the aforementioned housing member, and / or a separate housing component that complements the housing member—which may be at least partially housed within the housing member. For example, the camshaft is at least partially rotatably housed within the housing. Because a body is used to fix the leaf springs to the housing, the valve train can be installed or manufactured simply and at low cost.

[0021] Here, it is particularly advantageous that the body has at least one through-hole, which is preferably completely circumferentially defined by the body or by the wall of the body and thus completely closed around it. With the aid of the through-hole, the body and, consequently, the leaf spring are secured to the housing, thereby exhibiting a particularly simple and therefore time- and cost-effective valve train installation.

[0022] In order to secure the body and, consequently, the leaf spring or spring body to the housing in a particularly simple, time- and cost-effective manner, another design of the invention includes a threaded element, in particular a screw, passing through a through hole. By means of the threaded element, the body and, consequently, the leaf spring or spring body are threadedly connected to the housing, thereby securing it to the housing.

[0023] Finally, it proved particularly advantageous that the spring arm and the main body were integrally formed, and therefore the spring arm and the main body were made of the same material. The material is preferably a metal material or one of the aforementioned materials, especially a sheet of metal.

[0024] A second aspect of the invention relates to an internal combustion engine for motor vehicles, preferably designed as a piston machine or piston engine. The internal combustion engine has at least one valve train according to the first aspect of the invention. The advantages and advantageous designs of the first aspect of the invention should be considered as advantages and advantageous designs of the second aspect of the invention, and vice versa. Attached Figure Description

[0025] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and in conjunction with the accompanying drawings. The features and combinations thereof mentioned above in the specification, as well as those mentioned below in the description of the drawings and / or shown only in the drawings, may be used not only in their respective specified combinations, but also in other combinations or individually, without departing from the scope of the invention.

[0026] In the attached image:

[0027] Figure 1 A partial perspective view of the valve train mechanism for a motor vehicle internal combustion engine of the present invention is shown.

[0028] Figure 2 A partial top view of the valve train is shown;

[0029] Figure 3 Showing the valve train along Figure 2 A schematic diagram of a partial cross-section of the cutting plane A1-A1 shown;

[0030] Figure 4 Showing the valve train along Figure 3 A schematic diagram of a partial cross-section of the cutting plane A2-A2 shown;

[0031] Figure 5A perspective schematic diagram showing the spring body of the valve train, designed as a spring-loaded metal sheet. Detailed Implementation

[0032] In the accompanying drawings, identical or functionally identical parts are marked with the same reference numerals.

[0033] Figure 1 A partial perspective schematic diagram shows the valve train 10 of an internal combustion engine for a motor vehicle designed as a piston engine or piston machine. The motor vehicle is designed as an automobile, particularly a truck, and includes an internal combustion engine capable of driving the vehicle. The internal combustion engine has an engine block with multiple cylinders, i.e., multiple cylinders are directly formed or defined. Each piston is movably housed within its respective cylinder. Additionally, the internal combustion engine includes a housing component designed as a cylinder head, which is separately constructed from and connected to the engine block. The cylinder head has a combustion chamber top for each cylinder, wherein each combustion chamber of the internal combustion engine is defined by the respective cylinder, the respective piston movably housed within its respective cylinder, and the respective combustion chamber top. During ignition operation of the internal combustion engine, a combustion process takes place in each combustion chamber, wherein the fuel-air mixture is burned during each combustion process. This produces exhaust gases from the internal combustion engine. The cylinder head has at least one exhaust passage for each combustion chamber through which the corresponding exhaust gases can be discharged from each combustion chamber. In particular, the cylinder head has at least or exactly two exhaust ports for each combustion chamber. (This is from...) Figure 1 The first combustion chamber, as seen in the diagram, is equipped with two exhaust valves 12 and 14. Exhaust valve 12 is disposed in a first exhaust passage within the exhaust passages of the first combustion chamber, and exhaust valve 14 is disposed in a second exhaust passage within the exhaust passages of the first combustion chamber. Each exhaust valve 12 or 14 can be translatably moved relative to the cylinder head between a closed position and at least one open position. In the closed position, each exhaust valve 12 or 14 locks its corresponding exhaust passage. However, in its open position, each exhaust valve 12 or 14 opens its corresponding exhaust passage. The above and following description of the first combustion chamber, the exhaust passages disposed in the first combustion chamber, and the exhaust valves 12 and 14 can also be directly applied to other combustion chambers of an internal combustion engine, and vice versa.

[0034] The exhaust valve 12 is equipped with an engine brake rocker arm 16, which is mounted on a rocker arm shaft 18 such that the engine brake rocker arm 16 can pivot about a pivot axis 20 relative to the rocker arm shaft 18. The sump valve 14 is equipped with an exhaust rocker arm 22, which is mounted on a rocker arm shaft and can pivot about a pivot axis 20 relative to the rocker arm shaft 18. For example, during ignition operation, especially when the exhaust valves 12 and 14 stop operating due to the engine brake rocker arm 16, the exhaust valves 12 and 14 are particularly affected by the valve bridge 24 ( Figure 2The exhaust valves 12 and 14 can be actuated by means of the exhaust rocker arm 22, thus moving from their respective closed positions to their respective open positions. To actuate the valve bridge 24 and, consequently, to actuate the exhaust valves 12 and 14 via the valve bridge, the exhaust rocker arm 22 is pivoted and actuated relative to the rocker arm shaft 18 about the pivot axis 20. During engine braking operation of the internal combustion engine, the exhaust valve 12 can be actuated by means of the engine braking rocker arm 16, and thus can move from its closed position to its open position, especially when the actuation of the exhaust valve 14 stops. In other words, during engine braking operation, the exhaust valve 12 is actuated by means of the engine braking rocker arm 16, especially when the actuation of the exhaust valve 14 stops. For this purpose, the engine braking rocker arm 16 is pivoted relative to the rocker arm shaft 18 about the pivot axis 20. During engine braking operation, the internal combustion engine acts as an engine brake, which is particularly designed as a pressure-reducing brake. During engine braking, the ignition of the internal combustion engine ceases, therefore no combustion process occurs in the combustion chambers. During engine braking, at least primarily air-containing gas is introduced into each combustion chamber and compressed by the corresponding piston. By pivoting the engine braking rocker arm 16, the exhaust valve 12 is opened, allowing the compressed gas to be discharged from each combustion chamber. Thus, at least a large portion of the compression energy contained in the compressed gas is wasted and not used to move the piston from its top dead center to its bottom dead center. Therefore, the internal combustion engine performs compression work to compress the gas in the combustion chamber, but at least a large portion of the resulting compression energy is lost and cannot be used to move the piston from its top dead center to its bottom dead center. Thus, braking a motor vehicle during engine braking, or using engine braking, can prevent an undesirable excessive increase in the vehicle's speed.

[0035] Furthermore, the valve train 10 includes a camshaft 26 having a first cam 28 disposed on the engine brake rocker arm 16 and a second cam 30 disposed on the exhaust rocker arm 22. The cams 28 and 30 are coaxially arranged, wherein the camshaft 26 and consequently the cams 28 and 30 are rotatable relative to the cylinder head about an axis of rotation also referred to as the camshaft rotation axis. Here, the valve train 10 also includes a camshaft housing 32, in which the camshaft 26 is at least partially disposed, wherein the camshaft 26 and consequently the cams 28 and 30 are rotatable relative to the camshaft housing 32 about the camshaft rotation axis. It is conceivable that during ignition operation and during engine braking operation, the exhaust valves 12 and 14 are particularly actuated by means of the cam 28 via the valve bridge 24, i.e., by rotating the camshaft 26 and consequently by rotating the cam 30, the exhaust rocker arm 22 pivots about the pivot axis 20 relative to the rocker arm axis 18. Therefore, it is conceivable that during engine braking and ignition, the exhaust rocker arm 22 is actuated by the cam 30 and, consequently, by the camshaft 26, and thus pivots about the pivot axis 20. As the exhaust rocker arm 22 pivots about the pivot axis 20, the exhaust valves 14 and 12 are actuated, particularly via the valve bridge 24. It is conceivable that during engine braking, the exhaust valve 12 is actuated by the engine braking rocker arm 16, while the actuation of the exhaust valve 14 ceases. It is also preferable that, during ignition, the actuation of the exhaust valve 12 is not caused by the movement of the engine braking rocker arm 16. However, it is conceivable that during both engine braking and ignition, the engine braking rocker arm 16 pivots about the pivot axis 20 relative to the rocker arm shaft 18 by the cam 28 and, consequently, by the camshaft 26. In this case, the piston assembly, especially the engine brake rocker arm 16, can be configured to prevent the exhaust valve 12 from being operated by the engine brake rocker arm 16 during the ignition operation of the internal combustion engine, even though the engine brake rocker arm 16 is pivoted relative to the rocker arm shaft 18 by means of the cam 28 about the pivot axis 20 during the ignition operation.

[0036] For example, especially from Figure 4 As seen in the image, for example, the piston assembly includes a hydraulic piston, also known as piston 34, which has at least one such... Figure 4 The indicated retracted / retracted positions and at least one out position are particularly movable relative to the rocker arm body 36 and / or translational of the engine brake rocker arm 16. In the retracted position, although the engine brake rocker arm 16 pivots about the pivot axis 20, no actuation of the exhaust valve 12 occurs due to the movement of the engine brake rocker arm 16. However, in the out position, when the engine brake rocker arm 16 is pivoted about the pivot axis 20, the engine brake rocker arm 16 actuates the exhaust valve 12.

[0037] In order to move, for example, a piston 34, which is particularly designed as a hydraulic piston, from an inserted position to an removed position, fluid, especially a liquid, is introduced into a chamber, for example, arranged in the rocker arm body 36, such that the piston 34 is subjected to fluid action at least indirectly, and especially directly, and thereby moves from the inserted position to the removed position. This causes at least one length section of the piston 34 to be removed from the rocker arm body 36, wherein, in the inserted position, this length section is accommodated within the rocker arm body 36.

[0038] The exhaust rocker arm 22 has another rocker arm body 38. To allow for advantageous operation and, consequently, pivoting of the exhaust rocker arm 22 via an associated or corresponding cam 30, the exhaust rocker arm 22 has a cam follower designed as a roller 40, which is rotatably held on the rocker arm body 38 about a rotation axis 41, thus rolling or sliding on the cam 30 when the camshaft 26 and, consequently, the cam 30, are rotated. Thus, the exhaust rocker arm 22 is operated, i.e., pivoted, via its roller 40 by means of the cam 30. Correspondingly, the engine brake rocker arm 16 has a cam follower designed as a roller 42, which is rotatably held on the rocker arm body 36 about, for example, a roller rotation axis coinciding with the rotation axis 41. If the camshaft 26 and, consequently, the cam 28 are rotated relative to the cylinder head about the camshaft rotation axis, the roller 42 rolls or slides relative to the cam 28, thereby operating the engine brake rocker arm 16 via its roller 42, and thus pivoting it. Therefore, it can be seen that the engine brake rocker arm 16 can pivot about the pivot axis 20 by means of the cam 28.

[0039] Furthermore, the valve train 10 has a spring 44, which presses the engine brake rocker arm 16, in particular its rollers 42, against the camshaft 26, and especially the cam 28. This specifically means that the engine brake rocker arm 16, in particular its rollers 42, is kept in contact, and especially in direct contact, with the camshaft 26, and especially the cam 28, by means of the spring 44. For this purpose, the spring 44, for example, a mechanical spring in this case, provides spring force, thereby pressing the engine brake rocker arm 16, in particular its rollers 42, against the camshaft 26, and especially the cam 28.

[0040] It can also be seen that each exhaust valve 12 or 14 is equipped with its own valve spring 46 or 48. If each exhaust valve 12 or 14 moves from its respective closed position to its respective open position, the corresponding valve spring 46 or 48 is thus tightened, and in particular compressed. Therefore, each valve spring 46 or 48 provides spring force at least in the respective open position of the corresponding valve 12 or 14, thereby enabling the corresponding exhaust valve 12 or 14 to move to its respective closed position and, in particular, to remain in its respective closed position.

[0041] In order to keep the structural space requirements and costs of the valve train 10 and thus the internal combustion engine as a whole very low, the mechanical spring 44 is designed as a leaf spring 50.

[0042] Since the internal combustion engine has multiple combustion chambers as described above, the valve train 10 has multiple exhaust valves and multiple engine brake rocker arms, such as engine brake rocker arms 16. Here, the above and below description of engine brake rocker arms 16 can also be directly applied to other engine brake rocker arms, and vice versa. Therefore, the valve train 10 can be derived from... Figure 2 The description above and below of spring 44, which is designed as leaf spring 50, and other mechanical springs 52 are also shown. The description of spring 44 can be applied to mechanical spring 52, and vice versa. Here, mechanical spring 52 is also designed as a corresponding second leaf spring 54. With the help of each second leaf spring 54, the corresponding engine brake rocker arm is pressed against the corresponding cam of the camshaft 26, thereby compensating for errors in a cost-effective and space-efficient manner. It is specified here that leaf springs 50 and 54 are integrally formed. This means that leaf springs 50 and 54 are formed by a one-piece spring body 56, which is designed as or made of spring sheet metal. As a result, the number of parts of valve train 10 and thus the structural space requirements and costs can be kept very low, because in particular all leaf springs 50 and 54 can be installed simultaneously. It is also preferred that the spring body 56 and thus the leaf springs 50 and 54 are made of metal, especially metal sheets, thereby keeping costs very low.

[0043] From Figure 1 As seen in the diagram, the engine brake rocker arm 16 may have a spring seat 58, which can be integrally formed with or through the rocker arm body 36, for example. It is also conceivable that the spring seat 58 is separately formed from and connected to the rocker arm body 36. In particular, it is conceivable that the spring seat 58 is translatably held on the rocker arm body 36 relative to it. Thus, particularly while the spring seat 58 is held on or connected to the rocker arm body 36, it can, for example, move translatably relative to the rocker arm body 36 in the direction of movement. Here, it is particularly conceivable that the leaf spring 50 is directly supported on the spring seat 58 in the direction of movement. Because the spring seat 58 moves relative to the rocker arm body 36 in the direction of movement, the distance between the support surface of the spring seat 58 and the rocker arm body 36, extending particularly in the direction of movement, can be adjusted, wherein the leaf spring 50 is directly supported on, particularly against, or against the support surface. By adjusting the distance between the support surface and the rocker arm body 36, for example, the engine braking rocker arm 16 can be preloaded onto the cam 28 by the leaf spring 50. In other words, the spring force provided by the leaf spring 50 to press the engine braking rocker arm 16 against the camshaft 26, and especially the cam 28, can be adjusted.

[0044] In the embodiment shown in the figure, each leaf spring 50 or 54 is designed as a spring arm, which has the function of... Figure 1The longitudinal extension direction is indicated by the double arrow 60. The spring arm protrudes from the main body 62 of the spring body 56 along its longitudinal extension direction, so that the spring arm and the main body 62 are components of or constituted by the spring body 56. Here, the spring arm and the main body 62 are integrally formed. Because the spring arm protrudes from the main body 62, the spring arm is elastically held on or elastically connected to the main body 62, so that the engine brake rocker arm 16 can be advantageously pressed against the cam 28.

[0045] Leaf springs 50 and 54 are fixed to a housing, such as a cylinder head and / or camshaft housing 32, by a body 62 integrally formed with leaf springs 50 and 54. For this purpose, as can be seen from... Figure 2 As seen in the image, threaded components designed as screws 64 are provided. Each screw 64 passes through a corresponding through-hole in the body 62, and each through-hole is completely defined by the body 62 or its wall in the circumferential direction. By means of the screws 64 passing through the through-holes in the body 62, the spring body 56, the body 62, and the leaf springs 50 and 54 are screwed together with and thus fixed to the housing. Two of the through-holes in the body 62 are... Figure 3 It was seen in the middle and marked with 66 there.

[0046] Figure 5 A perspective view shows a one-piece spring body 56, which has a main body 62 and leaf springs 50 and 54. It can be clearly seen from... Figure 5 As seen, through holes 66 are formed in each lug 68, the lugs being integrally formed with the body 62 and protruding from the body 62 along the protruding direction, wherein the protruding direction extends obliquely or perpendicularly to the longitudinal extension direction of each leaf spring 50 or 54. The one-piece spring body 56 can be installed simply and therefore advantageously in terms of time and cost, thus allowing the leaf springs 50 and 54 to be installed simultaneously. Therefore, the valve train 10 can be manufactured or installed simply and therefore advantageously in terms of time and cost. To maintain a very low cost, the spring body 56 is preferably constructed as a punched and bent part, especially a punched and bent metal sheet part; therefore, the spring body 56 is preferably manufactured by punching and bending and is preferably made of metal sheet.

[0047] List of reference numerals

[0048] 10 Gas distribution mechanism 12 Exhaust valve 14 Exhaust valve 16 Engine brake rocker arm 18 rocker arm shaft 20 Pivot axis 22 Exhaust rocker arm 24 Valve bridge 26 Camshaft 28 Cam 30 Cam 32 Camshaft housing 34 piston 36 Rocker arm body 38 Rocker arm body 40 Roller 41 axis of rotation 42 Roller 44 Spring 46 Valve springs 48 Valve springs 50 leaf springs 52 Spring 54 leaf springs 56 Spring body 58 Spring seat 60 Double arrow 62 main body 64 screw 66 Through hole 68 protruding ears

Claims

1. A valve train (10) for an internal combustion engine, comprising: a first exhaust valve (12); a first engine brake rocker arm (16) pivotable about a pivot axis (20), by means of which the first exhaust valve (12) can be operated by pivoting the first engine brake rocker arm (16) during engine braking operation of the internal combustion engine; at least one camshaft (26) having at least one first cam (28) pivotable about the pivot axis (20); and a first spring (44) by means of which the first engine brake rocker arm (16) is pressed against the camshaft (26), wherein, The first spring (44) is designed as a first leaf spring (50); a second exhaust valve; a second engine brake rocker arm pivotable about the pivot axis (20), by means of which the second exhaust valve can be operated by pivoting the second engine brake rocker arm during engine braking operation of the internal combustion engine, wherein the camshaft (26) has a second cam that allows the second engine brake rocker arm to pivot about the pivot axis (20); and a second spring (52) pressing the second engine brake rocker arm against the camshaft (26), wherein the second spring (52) is designed as a second leaf spring (54). The first leaf spring (50) and the second leaf spring (54) are integrally formed.

2. The gas distribution mechanism (10) according to claim 1, characterized in that, The first leaf spring (50) and the second leaf spring (54) are made of metal.

3. The gas distribution mechanism (10) according to claim 1, characterized in that, The first leaf spring (50) and the second leaf spring (54) are designed to have spring arms extending in a longitudinal direction (60) that protrude from the body (62) along their longitudinal direction (60).

4. The gas distribution mechanism (10) according to claim 3, characterized in that, The first leaf spring (50) and the second leaf spring (54) are fixed to the housing (32) of the valve distribution mechanism (10) by the main body (62).

5. The gas distribution mechanism (10) according to claim 4, characterized in that, The body (62) has at least one through hole (66), through which the body (62) is fixed to the housing (32).

6. The gas distribution mechanism (10) according to claim 5, characterized in that, A threaded part (64) is provided through the through hole (66), by means of which the body (62) is threaded to the housing (32) and thus fixed to the housing (32).

7. The gas distribution mechanism (10) according to any one of claims 3 to 6, characterized in that, The spring arm is designed to be integrated with the main body (62).

8. An internal combustion engine for a motor vehicle, having at least one valve train (10) according to any one of claims 1 to 7.

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