Valve unit for an internal combustion engine and internal combustion engine for a motor vehicle

Abstract

The invention relates to a valve unit (10) for an internal combustion engine, comprising a gas exchange valve (12) which has a valve stem (14) and a valve area (16) provided for opening and closing a gas channel of the internal combustion engine, and a valve spring retainer (22) by means of which the valve unit (10) can be supported on a valve spring of the internal combustion engine, comprising a retaining ring (24) which engages both in a groove (26) of the valve stem (14) and in a groove (28) of the valve spring retainer (22), whereby the valve spring retainer (22) is secured on the valve stem (14) by means of the retaining ring (24) both in a first direction (30) extending in the longitudinal direction (20) of the valve stem (14) and in a second direction (32) extending in the longitudinal direction (20) of the valve stem (14) and opposite to the first direction (30).

Description

[0001] The invention relates to a valve unit for an internal combustion engine, in particular of a motor vehicle, according to the preamble of claim 1. Furthermore, the invention relates to an internal combustion engine for a motor vehicle, comprising at least one such valve unit.

[0002] US patent 3,762,382 A discloses a gas exchange valve for an internal combustion engine as a known invention. US patent 3,815,873 A also discloses a valve arrangement. DE 41 17 406 A1 discloses a valve train in a cylinder head of an internal combustion engine. DE 10 2014 007 011 A1 discloses a valve arrangement for an internal combustion engine.

[0003] The object of the present invention is to create a valve unit for an internal combustion engine, in particular of a motor vehicle, as well as an internal combustion engine with at least one such valve unit, so that a particularly advantageous design of the valve unit can be realized.

[0004] This problem is solved by a valve unit with the features of claim 1 and by an internal combustion engine with the features of claim 5. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect of the invention relates to a valve unit for an internal combustion engine, also referred to as a combustion engine or internal combustion power unit, particularly of a motor vehicle. This means that the motor vehicle, preferably designed as a motor vehicle, especially a passenger car, and simply also referred to as a vehicle, in its fully manufactured state comprises the internal combustion engine and can be driven by means of the internal combustion engine. The internal combustion engine, in its fully manufactured state, comprises the valve unit, so that the motor vehicle, in its fully manufactured state, has the valve unit. The valve unit comprises a gas exchange valve, which has a valve stem and a valve area provided or designed for opening and closing a gas channel of the internal combustion engine.For example, the valve section is designed as a valve disc, so that the gas exchange valve is preferably designed as a disc valve. In particular, it is provided that the valve stem has a first outer circumference, in particular a first outer diameter, wherein the valve section has a second outer circumference, in particular a second outer diameter, which is larger than the first outer circumference, in particular such that the largest outer circumference, in particular outer diameter, of the valve section is larger than the largest outer circumference, in particular than the largest outer diameter, of the valve stem. It is conceivable that the valve stem and the valve section are formed in one piece, that is, from a single component.

[0006] The gas passage of an internal combustion engine is a channel through which a gas can flow. For example, the gas passage is an intake port or an exhaust port. For example, the gas passage is bounded, in particular directly, by a cylinder head of the internal combustion engine, so that the gas passage runs within the cylinder head. For example, the gas passage leads into a combustion chamber of the internal combustion engine. For example, the internal combustion engine is designed as a reciprocating engine, i.e., a piston engine.

[0007] The valve assembly also includes a valve spring retainer, which is also simply referred to as a spring retainer. Preferably, the valve spring retainer is separate from the gas exchange valve, i.e., separate from the valve stem and separate from the valve area. The valve assembly can be supported on a valve spring of the internal combustion engine via the valve spring retainer. For this purpose, the valve spring retainer can be supported, in particular directly, on or against the valve spring, so that the gas exchange valve can be supported on or against the valve spring via the valve spring retainer.

[0008] In the fully assembled state of the internal combustion engine, the valve assembly is movable, in a manner known per se, along a direction of movement, also referred to as the axis of movement and extending along a straight line, relative to the cylinder head, at least translationally between a closed position and at least one open position. This means that the gas exchange valve and the valve spring retainer together are movable, at least translationally, along the direction of movement relative to the cylinder head between the open and closed positions. The valve stem extends longitudinally along its longitudinal direction, with, for example, the longitudinal direction of the valve stem coinciding with the direction of movement.

[0009] In the closed position of the valve unit, and thus of the gas exchange valve, the gas channel is closed by the valve section, i.e., fluidically blocked, in particular because, in the closed position, the valve section sits directly on a corresponding valve seat in the cylinder head. Thus, in the closed position, the valve section prevents the aforementioned gas from flowing through the gas channel, preventing gas from flowing from the combustion chamber into the gas channel or vice versa. In the open position, the valve section releases the gas channel, allowing gas to flow out of the gas channel and into the combustion chamber, or vice versa.If the gas channel is designed as an intake channel, for example, then the gas is or comprises at least air, which can be introduced into the combustion chamber via the intake channel and, in the open position, can flow out of the gas channel and into the combustion chamber. If the gas channel is, for example, an exhaust channel, then the gas is or comprises exhaust gas from the internal combustion engine, the exhaust gas of which can be discharged from the combustion chamber via the exhaust channel and, in the open position, can flow out of the combustion chamber and into the exhaust channel.

[0010] In particular, it is provided that the valve section is arranged at one end of the valve stem. In other words, the gas exchange valve, when considering only the gas exchange valve, has two ends opposite each other in the longitudinal direction of the valve stem and thus of the gas exchange valve, namely a first end and a second end. When considering only the gas exchange valve, it terminates at these ends in the longitudinal direction of the valve stem. The first end is formed, for example, by the valve stem, and the second end is formed, for example, by the valve section.

[0011] To achieve a particularly advantageous design of the valve assembly, the valve assembly features a retaining ring that is specifically designed separately from the gas exchange valve, and thus separately from the valve stem, the valve area, and the valve spring retainer. The retaining ring engages in a groove in both the valve stem and the valve spring retainer. The groove in the valve stem is also referred to as the first groove, and the groove in the valve spring retainer is also referred to as the second groove. For example, the first groove in the valve stem is designed as an annular groove that extends completely around the valve stem in a circumferential direction, thus covering a full 360 degrees.Furthermore, it is conceivable that the second groove in the valve spring retainer is designed as an annular groove extending completely around the valve stem in the circumferential direction, thus covering 360 degrees. Because the retaining ring engages in the grooves, it is partially located in the first groove and partially in the second. This also results in the retaining ring forming a positive-locking connection with both the valve stem and the valve spring retainer. By engaging the grooves, the retaining ring secures the valve spring retainer to the valve stem in both a first direction running in the longitudinal direction of the valve stem and a second direction running in the same longitudinal direction but opposite to the first.This means that relative movements between the valve spring retainer and the valve stem, both in the first direction and in the second direction, are at least limited or prevented by the retaining ring. This allows undesirable, excessive relative movements between the valve spring retainer and the valve stem to be avoided in a cost-effective and space-saving manner. The valve unit according to the invention can be assembled, i.e., manufactured, cost-effectively. The gas exchange valve, the valve spring retainer, and the retaining ring are individual components of the valve unit, and these components can each be manufactured cost-effectively, thus enabling a particularly cost-effective design of the valve unit. Furthermore, the number of parts in the valve unit can be kept very low, and excessively high moving masses can be avoided.

[0012] The invention is based in particular on the following knowledge and considerations: The valve spring retainer is usually secured to the valve stem by means of a so-called valve wedge. However, this can result in certain disadvantages. One disadvantage is that the valve assembly then comprises a large number of small individual parts. This leads to complex assembly of the valve assembly. Furthermore, it has been found that when the valve spring retainer is secured to the valve stem by means of a valve wedge, the gas exchange valve does not rotate, or rotates only very slightly, relative to the cylinder head, particularly around the longitudinal direction of the valve stem, in an internal combustion engine speed range of less than 2000 revolutions per minute. This can lead to soot deposits in the area of ​​the valve seat, which can result in further disadvantages.The valve spring retainer secured to the valve stem by means of the retaining ring, as provided in the invention, prevents the formation of excessive amounts and / or excessively rapid deposits, particularly in the area of ​​the valve seat. This is because the gas exchange valve can rotate advantageously relative to the cylinder head, especially around the longitudinal direction of the valve stem, within the aforementioned speed range. This ensures uniform wear of the gas exchange valve on or in the valve seat, thus preventing the undesirably rapid development of leaks in the valve seat area. Consequently, efficient operation of the internal combustion engine can be guaranteed over a long service life.

[0013] In order to secure the valve spring retainer to the valve stem in a particularly advantageous manner and thus achieve a particularly advantageous design of the valve assembly, the invention provides that the valve stem completely penetrates a through-opening of the valve spring retainer, particularly in the longitudinal direction of the valve stem. The retaining ring is arranged in the through-opening.

[0014] For example, it is intended that the valve spring retainer, and thus the retaining ring, is located closer to the first end of the gas exchange valve than to the second end or the valve area when viewed in the longitudinal direction of the valve stem. In particular, it is conceivable that the valve spring retainer is located at the first end.

[0015] It is also intended that a section of the through-hole tapers towards the retaining ring in the longitudinal direction of the valve stem. For example, this section of the through-hole is conical on its inner circumference, forming a funnel or funnel stub. This section of the through-hole can, for instance, serve as an insertion ramp in a manufacturing and assembly process for the valve unit, allowing the valve stem to be inserted through the through-hole particularly easily, and therefore quickly and cost-effectively, especially along its longitudinal direction. This enables the valve unit to be manufactured and assembled in a particularly time- and cost-efficient manner.

[0016] To achieve a particularly advantageous design of the valve unit, the invention provides that the retaining ring is elastically deformed in the second groove, such that the retaining ring is in an elastically deformed state in which it engages in both the first and second grooves. This prevents relative movements between the valve spring retainer and the valve stem in both directions. As a result, the valve spring retainer can be secured particularly advantageously to the valve stem and thus to the gas exchange valve.

[0017] In a further, particularly advantageous embodiment of the invention, the valve spring retainer has at least two additional openings opposite each other, in addition to the through-opening. Each of these openings opens at one end into the vicinity of the valve spring retainer and at the other end to the retaining ring. In particular, the openings are arranged uniformly in the circumferential direction of the valve stem and thus of the valve spring retainer, extending around the longitudinal direction of the valve stem, such that, for example, the openings are spaced apart from each other by 180 degrees when viewed in the circumferential direction of the valve stem. For example, a tool can be inserted through the through-opening, thereby bringing the tool into, and in particular direct, contact with the retaining ring and thus into, and in particular direct, interaction with the retaining ring.The tool can then be used, for example, to compress the retaining ring and thereby move it towards the valve stem, for example further into the first groove of the valve stem, thus reducing its outer circumference and moving it out of the second groove of the valve spring retainer, after which the valve stem can be pulled out of the valve spring retainer, in particular out of its through-hole.

[0018] This allows the valve unit to be disassembled quickly and cost-effectively. The openings thus enable a particularly advantageous design of the valve unit, especially in that they ensure particularly simple and therefore quick and cost-effective disassembly.

[0019] To enable particularly easy, and therefore time- and cost-effective, disassembly of the valve unit, a further embodiment of the invention provides that the through-directions of the openings converge towards the retaining ring. This allows the aforementioned tool to be guided precisely by means of the openings and, in particular, precisely to the retaining ring, whereupon the retaining ring is compressed and, consequently, the valve stem and thus the gas exchange valve can be removed from the valve spring retainer.

[0020] A second aspect of the invention relates to an internal combustion engine, also referred to as an internal combustion engine or combustion power engine, and preferably designed as a reciprocating piston engine, i.e., a piston engine, for a motor vehicle, also referred to simply as a vehicle, and preferably designed as a motor car, in particular a passenger car, wherein the internal combustion engine has at least one valve unit according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

[0021] Also disclosed is a third aspect, not belonging to the invention, which relates to a method for manufacturing, i.e., assembling, a valve unit, particularly according to the first aspect of the invention, for an internal combustion engine. In this method, a gas exchange valve is provided, which has a valve stem extending longitudinally along its longitudinal direction and a valve area designed, for example, as a valve disc, for opening and closing a gas port of the internal combustion engine. In this method, a valve spring retainer, designed separately from the gas exchange valve and thus separately from the valve stem and separately from the valve area, is provided, by means of which the valve unit can be supported or is supported on a valve spring of the internal combustion engine.

[0022] For example, the valve spring retainer and, via the valve spring retainer, the valve assembly can be supported or supported on the valve spring along the aforementioned direction of movement, in particular such that the valve spring retainer can be supported or supported on the valve spring along the direction of movement, in particular directly. When the gas exchange valve, and thus the valve assembly as a whole, moves from the closed position to the open position along the direction of movement and in particular relative to the cylinder head, the valve spring is, for example, tensioned, in particular compressed, whereby the valve spring, at least in the open position, provides a spring force acting, in particular along the direction of movement, from the valve spring to the valve assembly, which acts, for example, along the direction of movement from the valve spring to the valve spring retainer and, via this, to the valve assembly.The spring force moves the valve unit, and thus the gas exchange valve, from the open position to the closed position. In particular, the longitudinal direction of the valve stem coincides with the direction of movement.

[0023] In order to achieve a particularly advantageous design of the valve unit and thus to be able to manufacture, i.e., assemble, the valve unit in a particularly time- and cost-effective manner, the third aspect provides that the gas exchange valve, the valve spring retainer, and a retaining ring, which is designed separately from the gas exchange valve and separately from the valve spring retainer, are mounted together in such a way that the retaining ring engages both in a first groove of the valve stem and in a second groove of the valve spring retainer, whereby the valve spring retainer is secured to the valve stem by means of the retaining ring in both a first direction extending in the longitudinal direction of the valve stem and in a second direction extending in the longitudinal direction of the valve stem and opposite to the first direction.This at least limits or prevents relative movements between the valve spring retainer and the valve stem in both directions. Advantages and advantageous embodiments of the first and second aspects of the invention are to be regarded as advantages and advantageous embodiments of the third aspect, and vice versa.

[0024] To achieve a particularly advantageous design of the valve unit, thereby enabling particularly simple and thus time- and cost-effective manufacturing and assembly, one embodiment of the third aspect provides that, before the retaining ring engages with the second groove of the valve spring retainer, it engages in the first groove of the valve stem and is thus held against the valve stem. This means that—before the retaining ring engages with the second groove of the valve spring retainer—the gas exchange valve and the retaining ring form a pre-assembled unit. The unit is thus pre-assembled, for example, before the retaining ring engages with the second groove of the valve spring retainer, such that the retaining ring engages with the first groove of the valve stem and is thus held against the valve stem.For example, before the retaining ring engages with the second groove of the valve spring retainer, it rests loosely in the first groove of the valve stem, without being elastically deformed. After this manufacturing or pre-assembly of the unit, the valve stem is inserted along its longitudinal direction through a through-hole in the valve spring retainer, the second groove of which opens into the through-hole. This engages the retaining ring with the second groove of the valve spring retainer and secures or mounts it to the valve stem.When the valve stem is inserted through the opening of the valve spring retainer, the retaining ring, which is initially loose in the first groove of the valve stem and / or not elastically deformed, is compressed, thus reducing its outer circumference and moving further into the first groove of the valve stem, particularly until the first groove of the valve stem overlaps with the second groove of the valve spring retainer. Once the first groove of the valve stem overlaps with the second groove of the valve spring retainer, the retaining ring can at least partially relax and move into the second groove of the valve spring retainer, particularly by springing back. This causes the retaining ring to engage with the second groove of the valve spring retainer and subsequently engage both the first groove of the valve stem and the second groove of the valve spring retainer.This allows the valve unit to be installed in a particularly time- and cost-effective manner.

[0025] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0026] The drawing shows in: Fig. 1 a schematic side view of a valve unit for an internal combustion engine of a motor vehicle; Fig. 2 another schematic side view of the valve unit; Fig. 3 a schematic top view of the valve unit; and Fig. 4. Partial schematic sectional view of the valve unit along a [line / section] Fig. Section 3 AA shown with a transparently represented valve plate.

[0027] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0028] Fig. Figure 1 shows a schematic side view of a valve unit 10 for an internal combustion engine of a motor vehicle. This means that the internal combustion engine, in its fully manufactured state, includes the valve unit 10. The motor vehicle, in its fully manufactured state, includes the internal combustion engine and thus the valve unit 10, and can be propelled by the internal combustion engine. The internal combustion engine is, for example, designed as a reciprocating engine and has at least one combustion chamber in which combustion processes take place during operation. In each combustion process, a fuel-air mixture is burned, resulting in exhaust gas from the internal combustion engine.The respective fuel-air mixture comprises, in particular, a liquid fuel and air, also referred to as fresh air or combustion air. The combustion chamber is partially bounded by a cylinder formed by an engine block. The engine block is, for example, a cylinder housing, in particular a cylinder crankcase. The combustion chamber is also partially bounded by a piston, which is arranged to move translationally within the cylinder. The combustion chamber is also partially bounded by a combustion chamber roof. The combustion chamber roof is formed by a cylinder head of the internal combustion engine, which is designed separately from the engine block and is at least indirectly connected to the engine block. The cylinder head has a gas channel through which a gas can flow, in particular such that the gas can be discharged from the combustion chamber by means of the gas channel or that the gas can be introduced into the combustion chamber by means of the gas channel.For example, the gas is or comprises the aforementioned air. Furthermore, it is conceivable that the gas is the aforementioned exhaust gas. As will be explained in more detail below, the valve unit 10 is associated with the gas channel. The valve unit 10 has a gas exchange valve 12, which has a valve stem 14 and a valve area 16 designed or configured for opening and closing the gas channel. From . Fig. It can be seen from Figure 1 that in the embodiment shown in the figures, the valve section 16 is a so-called valve disc, so that in the embodiment shown in the figures, the gas exchange valve 12 is designed as a disc valve known per se. This is evident from Fig. It is also evident that the valve stem 14 extends longitudinally along its longitudinal direction, illustrated by a double arrow 18, with the longitudinal direction of the valve stem 14 running along an imaginary straight line 20. For example, at least a length region of the valve stem 14 and the valve section 16 are rotationally symmetrical with respect to the longitudinal direction 20. The gas exchange valve 12 has two ends opposite each other in the longitudinal direction 20 of the valve stem 14, namely a first end E1 and a second end E2. It can be seen that the valve stem 14 forms end E1 and that the valve section 16 forms end E2. The gas exchange valve 12 terminates at ends E1 and E2 when viewed in the longitudinal direction 20 of the valve stem 14.The valve unit 10, and thus the gas exchange valve 12, is translationally movable relative to the cylinder head along a direction of movement that coincides with the longitudinal extension 20 of the valve stem 14 and thus with the line 20, and is also referred to as the axis of movement, between a closed position and at least one open position, in particular at least or exclusively. In the closed position, the valve section 16 sits, in particular directly, on a corresponding valve seat of the cylinder head, thereby closing the gas channel, i.e., fluidically blocking it. In the open position, the valve section 16 is, in particular completely, spaced away from the valve seat, thereby releasing the gas channel, i.e., opening it.

[0029] The valve unit 10 is associated with a spring element (not shown in the figures), which is also referred to as a spring or valve spring. The valve unit 10 can be supported or is supported along the direction of movement, in particular directly, on the valve spring, so that by moving the valve unit 10 from the closed position to the open position along the direction of movement and relative to the cylinder head, the valve spring is tensioned or is tensioned along the direction of movement such that it is compressed or is compressed along the direction of movement. Thus, at least in the open position, the valve spring provides a spring force, acting particularly along the direction of movement, on the valve unit 10, by means of which the valve unit 10 can be moved from the open position to the closed position relative to the cylinder head.

[0030] The valve unit 10 has a valve spring plate 22 which is formed separately from the gas exchange valve 12 and thus separately from the valve stem 14 and separately from the valve area 16, by means of which the valve unit 10 can be supported or supported on the valve spring of the internal combustion engine along the direction of movement, such that the valve spring plate 22 can be supported or supported on the valve spring along the direction of movement, in particular directly, on the valve spring.

[0031] In order to achieve a particularly advantageous design of the valve unit 10 and thus to be able to manufacture, i.e., assemble, the valve unit 10 has a particularly well-designed component that is separate from the gas exchange valve 12 and separate from the valve spring plate 22. Fig. 4 recognizable retaining ring 24. The retaining ring 24 engages both in a first groove 26 of the valve stem 14 and in a second groove 28 of the valve spring retainer 22, thereby securing the valve spring retainer 22 to the valve stem 14 by means of the retaining ring 24 in both a first direction extending in the longitudinal direction 20 of the valve stem 14, illustrated by an arrow 30, and in a second direction extending in the longitudinal direction 20 of the valve stem 14, opposite to the first direction and illustrated by an arrow 32. The first groove 26 and the second groove 28 are in Fig. Figure 2 illustrates this. The retaining ring 24 is shown in Fig. 2 not shown. The feature that the respective direction runs in the longitudinal extension direction 20 of the valve stem 14 means that the respective direction runs to the longitudinal extension direction 20 of the valve stem 14 or coincides with the longitudinal extension direction 20 of the valve stem 14.

[0032] For example, the retaining ring 28 is made of a metallic material, in particular of steel and most especially of spring steel. The retaining ring 24 extends, for example, in the circumferential direction of the valve stem 14 around the longitudinal extension direction 20 of the valve stem 14 over more than 270 degrees, in particular over more than 300 degrees, around the valve stem 14. The circumferential direction of the valve stem 14 is indicated by a double arrow 34 pointing Fig. 1 is illustrated and runs in a plane which is perpendicular to the longitudinal extension direction 20 of the valve stem 14 and thus perpendicular to the line 20.

[0033] It is evident that the gas exchange valve 12, the retaining ring 24, and the valve spring retainer 22 are components of the valve unit 10, several of which can be made particularly small. Furthermore, the cost of each individual component can be kept especially low, resulting in a particularly cost-effective design for the valve unit 10. Additionally, the weight of each individual component can be kept particularly low, resulting in a very low overall weight for the valve unit 10. This avoids excessively high moving masses. Furthermore, it can be designed, for example, that the gas exchange valve 12 rotates advantageously relative to the cylinder head, and thus relative to the valve seat, particularly around the direction of movement, within a rotational speed range of the internal combustion engine of, for example, less than 2000 revolutions per minute.This prevents excessive deposits, especially soot deposits, on the valve seat and ensures advantageously uniform wear of the valve seat. This also guarantees that the gas exchange valve 12 seals the gas channel sufficiently tightly in its closed position, even over a long service life of the internal combustion engine.

[0034] Out of Fig. 2 and Fig. Figure 4 clearly shows that the valve stem 14 penetrates a through-opening 36 of the valve spring retainer 22, particularly in the longitudinal direction 20 of the valve stem 14, and preferably completely. The retaining ring 24 is arranged in the through-opening 36 of the valve spring retainer 22. A length L1 of the through-opening 36 tapers in the longitudinal direction 20 of the valve stem 14 towards the retaining ring 24, in particular in this case such that the length L1 is funnel-shaped on its inner circumference. The length L1, or the winding sections of the valve spring retainer 22 forming the length L1, thus acts as an insertion ramp, which, as will be explained in more detail below, allows the valve assembly 10 to be mounted quickly and cost-effectively.

[0035] Out of Fig. Figure 3 shows that the valve spring retainer 22 has several, and in this case at least or exactly four, additional openings 38a-d provided alongside the through-opening 36, each of which is at least partially separated from the through-opening 36 such that a wall region of the valve spring retainer 22, in particular designed as a solid body, is arranged between the through-opening 36 and the respective opening 38a-d. The openings 38a and 38b form a first pair of openings, and the openings 38c and 38d form a second pair of openings. It is evident that the respective openings 38a-d of each pair of openings, viewed particularly in the radial direction of the valve stem 14, whose radial direction is perpendicular to the longitudinal direction of the valve stem 14 and thus, for example, runs in the aforementioned plane, are opposite each other and thus, for example, spaced apart from each other by 180 degrees in the circumferential direction of the valve stem 14.In the embodiment shown in the figures, the openings 38a-d are arranged evenly spaced around the circumference of the valve stem 14 and are thus equally spaced apart in pairs. Fig. As can be seen from the example of openings 38c and 38d, each opening 38a-d opens at one end into the surrounding area 40 of the valve spring retainer 22 and, in this case, the valve unit 10 as a whole, and at the other end into the retaining ring 24. Each opening 38a-d is continuous along its respective direction of travel, such that it opens at one end into the surrounding area 40 and at the other end into the retaining ring 24, in particular directly. Thus, for example, a tool can be inserted through the openings 38a-d and thereby moved into a support position with the retaining ring 24, and thus into direct interaction with the retaining ring 24.Then, using the tool, which is in direct support of the retaining ring 24, the retaining ring 24 can be compressed, thus reducing its outer circumference and moving it further into the groove 26, in particular until the retaining ring 24 is moved out of the second groove 28 of the valve spring retainer 22. Once the retaining ring 24 is moved out of the second groove 28, so that it no longer engages in the second groove 28 or at least not fully engages, the valve stem 14 can be pulled out of the through-opening 36 and thus out of the valve spring retainer 22, or the valve spring retainer 22 can be pulled off the valve stem 14, allowing the valve assembly 10 to be disassembled quickly and cost-effectively.

[0036] In the fully assembled state of the valve unit 10, the retaining ring 24 is elastically deformed in the second groove 28, such that the retaining ring 24 is in an elastically deformed state in which it engages in both the first groove 26 and the second groove 28. The retaining ring 24 rests completely in the second groove 28. This prevents, for example, relative movements between the valve spring retainer 22 and the valve stem 14 in both directions 30 and 32.

[0037] Recognizable from Fig. 4. Using the example of openings 38c and 38d, the passage direction of openings 38a-d, which run along a respective straight line, converges towards the retaining ring 24.

[0038] The following describes a method for manufacturing, i.e., assembling, the valve unit 10. In this method, the gas exchange valve 12, the valve spring retainer 22, and the retaining ring 24 are assembled such that the retaining ring 24 engages in both the first groove 26 and the second groove 28. For this purpose, for example, before the retaining ring 24 is engaged with the second groove 28, a pre-assembled unit is formed, comprising the gas exchange valve 12 and the retaining ring 24. With regard to the gas exchange valve 12, the valve spring retainer 22, and the retaining ring 24, the unit comprises only the gas exchange valve 12 and the retaining ring 24.To form and thus pre-assemble the unit, before the retaining ring 24 engages with the second groove 28, it is first engaged with the first groove 26. This allows the retaining ring 24 to engage with the first groove 26 without engaging with the second groove 28, and thus be held against the valve stem 14. In particular, the retaining ring 24 rests loosely in the first groove 26. After forming the pre-assembled unit, the valve stem 14 is inserted through the through-hole 36 along its longitudinal direction 20, or conversely, the valve spring retainer 22 is threaded or slipped onto the valve stem 14 along its longitudinal direction. This engages the retaining ring 24, in particular, with the second groove 28.When the valve stem 14 is inserted through the through-opening 36 or when the valve spring retainer 22 is placed onto the valve stem 14, the length section L1 is used as an insertion chamfer to align the valve stem 14 easily and precisely relative to the valve spring retainer 22. Furthermore, when the valve stem 14 is inserted through the through-opening 36 or when the valve spring retainer 22 is placed or threaded onto the valve stem 14, the retaining ring 24 is elastically deformed, thereby reducing its outer circumference and moving further into the first groove 26, in particular until the first groove 26 overlaps with the second groove 28.As soon as the first groove 26 overlaps with the second groove 28, the retaining ring 24 can at least partially relax and thus spring back into the second groove 28, whereupon the retaining ring 24 engages in both the first groove 26 and the second groove 28. In other words, the unit is pre-assembled such that the retaining ring 24 engages in the first groove 26 without engaging in the second groove 28. Subsequently, the valve stem 14 and the retaining ring 24 held or pre-mounted on it are inserted through the through-opening 36, particularly in the longitudinal direction 20 of the valve stem 14. Alternatively, the valve spring retainer 22 is pulled over the valve stem 14 and the retaining ring 24 held and thus pre-mounted on it, particularly along the longitudinal direction 20 of the valve stem 14.The retaining ring 24 slides, particularly directly, along the length section L1 and thus along the insertion chamfer, thereby compressing the retaining ring 24 and moving it further into the first groove 26. As soon as the first groove 26 overlaps with the second groove 28, the retaining ring 24 can at least partially relax and thus expand radially outwards, i.e., in the radial direction of the valve stem 14 and the retaining ring 24, and consequently fit snugly into the second groove 28. As a result, the retaining ring 24 is positioned in the two grooves 26 and 28 such that it is supported against the valve stem 14 in the first groove 26 and simultaneously against the valve spring retainer 22 in the second groove 28.This secures the valve spring retainer 22 to or on the valve stem 14 in both the first direction 30 and the second direction 32, and in particular secures it against displacement relative to the valve stem 14, both in the first direction 30 and in the second direction 32.

[0039] The tool comprises, for example, individual mandrels that are inserted through the openings 38a, d and thereby moved into direct interaction with the retaining ring 24. For example, the respective opening 38a-d is formed as a bore and thus by machining.

[0040] The described securing of the valve spring retainer 22 to the valve stem 14 by means of the retaining ring 24, also simply referred to as a ring, allows the gas exchange valve 12 to rotate slightly relative to the cylinder head, particularly in the direction of movement, especially during each compression of the valve spring. The compression and subsequent release of the valve spring generates a torque that rotates the valve spring retainer 22, particularly in the direction of movement and relative to the cylinder head. A portion of this rotation of the valve spring retainer 22 is transmitted to the valve stem 14 and thus to the gas exchange valve 12, causing the gas exchange valve 12 to rotate in the direction of movement and relative to the cylinder head. This does not occur if the valve spring retainer 22 is secured to the valve stem 14 by means of a wedge connection, such as one formed by valve keepers.Thus, at least the following advantages can be realized: - Very easy assembly, as no valve wedges need to be laboriously installed, so the valve unit 10 can be manufactured and assembled in a time- and cost-effective manner. - particularly high safety against assembly errors - significantly less effort required for quality assurance of components, since, for example, valve wedges are very time-consuming to measure. - The gas exchange valve 12 can rotate relative to the cylinder head, especially around the direction of movement, even at low engine speeds, so that excessive wear and excessive deposits can be avoided.

Claims

[1] Valve assembly (10) for an internal combustion engine, comprising a gas exchange valve (12) which has a valve stem (14) and a valve area (16) provided for opening and closing a gas channel of the internal combustion engine, and a valve spring retainer (22) by means of which the valve assembly (10) can be supported on a valve spring of the internal combustion engine, wherein a retaining ring (24) is provided which engages both in a first groove (26) of the valve stem (14) and in a second groove (28) of the valve spring retainer (22), whereby the valve spring retainer (22) is secured on the valve stem (14) by means of the retaining ring (24) both in a first direction (30) extending in the longitudinal direction (20) of the valve stem (14) and in a second direction (32) extending in the longitudinal direction (20) of the valve stem (14) and opposite to the first direction (30),and wherein the valve stem (14) penetrates a through-opening (36) of the valve spring retainer (22), in the through-opening (36) of which the retaining ring (24) is arranged; , characterized by , that the retaining ring (24) is elastically deformed in the second groove (28), such that the retaining ring (24) is in an elastically deformed state in which the retaining ring (24) engages in both the first groove (26) and the second groove (28), thereby preventing both relative movements in the first direction (30) between the valve spring retainer (22) and the valve stem (14) and relative movements in the second direction (32) between the valve spring retainer (22) and the valve stem (14), and wherein a length region (L1) of the through-hole (36) tapers towards the retaining ring (24) in the longitudinal extension direction (20) of the valve stem (14). [2] Valve unit (10) according to claim 1, characterized by, that the valve spring plate (22) has at least two additional openings (38a, 38b) provided in addition to the through-opening (36) and opposite each other, which each open at one end into a surrounding (40) of the valve spring plate (22) and at the other end to the retaining ring (24). [3] Valve unit (10) according to claim 2, characterized by , that a respective direction of passage of the respective opening (38a, 38b), which opens at one end into the surroundings (40) of the valve spring plate (22) and at the other end into the retaining ring (24), runs obliquely to the longitudinal extension direction (20) of the valve stem (14). [4] Valve unit (10) according to claim 3, characterized by , that the directions of passage of the openings (38a, 38b) run towards each other in the direction of the retaining ring (24). [5] Internal combustion engine for a motor vehicle, comprising at least one valve unit (10) according to any of the preceding claims.

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