EP3870814A1

EP3870814A1 - Internally cooled valve having a coolant conducting system

Info

Publication number: EP3870814A1
Application number: EP19812758.1A
Authority: EP
Inventors: Parth MISTRY; Stefan Kellermann; Guido Bayard; Jens GÄRTNER
Original assignee: Federal Mogul Valvetrain GmbH
Current assignee: Federal Mogul Valvetrain GmbH
Priority date: 2019-02-25
Filing date: 2019-11-27
Publication date: 2021-09-01
Anticipated expiration: 2039-11-27
Also published as: WO2020173587A1; DE102019104659A1; EP3870814B1

Abstract

The present invention relates to an internally cooled valve (2), having a valve body (4) which comprises a valve stem (6) and a valve head (8), wherein a cavity (10) in the valve body (4) extends from the valve stem (6) into the valve head (8) and has a greater diameter (D) in the valve head region (12) than in a valve stem region (14). An equalising channel (16) is arranged in the valve (2) and extends between the valve stem region (14) of the cavity into a valve head region (14) of the cavity (10).

Description

Internally cooled valve with coolant control system

The present invention relates to an internally cooled valve with a coolant control system.

Sodium-cooled valves should ideally be operated by what is known as shaker cooling, in which heat energy that is absorbed by the coolant at a valve head is transported to the valve stem by a movement of the coolant in order to be diverted through the cooled cylinder head or its cooled valve guides .

The shaker cooling does not always work as desired, however, especially if there is a gas in the cavity of the internally cooled valve in addition to the coolant, it can happen that this gas is only compressed, and thereby the movement of the incompressible coolant in the cavity hindered, since the coolant and the gas can not easily flow past each other.

A simple solution is to fill and close the valve under vacuum conditions, but this is very complex and expensive. It is therefore preferred to use a protective gas instead of a vacuum when filling the cavity, since a gas also reduces the load on the valve.

The present invention seeks to reduce this problem, or to avoid or at least reduce the effects emanating from a compressible gas in the cavity next to the coolant itself.

According to a first embodiment of the present invention, an internally cooled valve with a coolant control system is provided. The valve comprises a valve body with a valve stem and a valve head. In the valve body there is a cavity which extends from the valve stem into the valve head. The cavity has a larger diameter in the radial direction in the area of the valve head than in an area of the valve stem. A compensation channel is arranged in the cavity, which extends between a valve stem end of the cavity into a valve head end of the cavity.

In an exemplary embodiment of the internally cooled valve, the cavity has a transition area in which the diameter of the cavity tapers from a largest diameter in the valve head to a smaller diameter in the valve stem, and the channel ends in one half of the transition area in the valve head, which continues lies on a valve base.

In another exemplary embodiment of the internally cooled valve, the cavity has a transition area in which the diameter of the cavity tapers from a largest diameter in the valve head to a smaller diameter in the valve stem, and the channel ends in a third of the transition area in the valve head, which further lies on a valve base.

In an additional exemplary embodiment of the internally cooled valve, the cavity has a transition region in which the diameter of the cavity tapers from a largest diameter in the valve head to a smaller diameter in the valve stem, and the channel ends in front of this transition region of the valve head close to a valve base . Here the end of the channel lies between the transition area and the valve base.

These designs ensure that the end of the channel that protrudes into or out of the transition area first "dries out" at the end of a closing movement of the valve. After only a small part of the coolant has penetrated into the channel, a larger column of coolant can form in the cavity, which causes a remainder of the coolant to be pushed out of the channel against the main direction of movement of the coolant, and remaining compressed residual gas through the channel can escape. Since the residual gas can flow through the channel towards the valve head, it no longer hampers the movement of the coolant, which improves shaker cooling.

In a further exemplary embodiment of the internally cooled valve, the channel runs parallel to an axial direction of the valve body or the valve. Here the cavity and the channel can run parallel to one another in the valve stem.

In a further exemplary embodiment, the compensation channel is tubular. This design concerns a channel that is rectangular or polygonal or circular Has cross section.

In an additional embodiment, the compensation channel is formed by a tube which is arranged in the cavity. The tube runs through the cavity and through the stem of the valve and is open at both ends to the cavity.

In an exemplary embodiment, the cavity is essentially rotationally symmetrical. In another embodiment, the entire valve or at least the valve body is rotationally symmetrical.

Another exemplary embodiment uses a tube as a channel which runs essentially coaxially to the cavity or to the valve stem. Here, the rotationally symmetrical thermal loads can have the least effect on the operation of the valve or the motor.

Another exemplary embodiment uses a tube as a channel which runs essentially at or near the edge of the cavity. Capillary forces can have a stronger effect here, which only occur with the coolant but not with the remaining gas in the cavity. The tube is preferably arranged close to the edge, so that the coolant can also flow between the tube and the stem and an uneven temperature distribution in the valve stem with the resulting deformations can thus be avoided. In one embodiment, the tube runs eccentrically through the shaft.

In one embodiment of the valve, the tube is beveled at at least one end. The bevel makes it possible to easily generate a defined inflow or outflow opening without having to make separate bores on the pipe.

In another embodiment, the tube has an angle or an angle piece or a bend at at least one end. Here, the tube can be designed bent by 45 ° to 90 °, for example. By means of a bend, a larger area of the pipe can be provided for connection to the valve base, especially on a valve base.

In another exemplary embodiment, the tube is welded to an inside of the cavity at at least one end. Friction welding, electron beam welding or laser welding as well as resistance welding can be used here. In an additional embodiment, the tube is clamped at least at one end to an inside of the cavity. There should be a frictional connection here in order to hold the pipe in the axial direction or in the radial direction. For example, the pipe can be welded to a valve cover and inserted and welded together with the cover in a valve blank open towards the valve base.

In a further embodiment, the tube is held at least at one end with an inside of the cavity by a form fit. Here, for example, recesses or guide pins can be provided in the valve stem end and / or on the valve base, which hold and fix the tube in the cavity.

In an additional embodiment of the internally cooled valve, radially extending centering elements are arranged on the tube, which hold the tube coaxially to the cavity. These centering elements are intended to reduce a gap between the tube and an inner surface of the cavity as little as possible.

In a further exemplary embodiment of the internally cooled valve, the valve stem and the valve head are made in one piece. One-piece means here that there is no weld seam between the valve stem and the valve head, and the valve head also has no weld seam. Here the valve is for the most part not produced by machining but by forming. In this embodiment, the valve is produced from a cup-shaped semi-finished product which is reshaped in such a way that the or a base widens downwards and forms a valve disk. This first shape also has an essentially cylindrical cavity. In further steps, a wall area that lies above the floor is tapered and stretched more and more, so that a cavity is created that has a larger diameter in the head than in a shaft. The tapering, which can be carried out over a dome, further increases the length of the wall and thus of the shaft. When the shaft has reached a sufficient length and the equalizing channel and the coolant are introduced into the cavity, the cavity can be closed, for example by attaching a valve stem end by friction welding. It is also possible to close a shaft end that is open in the axial direction by rolling it together, with a section with an increased wall thickness preferably being present at the shaft end so that the shaft has a constant or uniform outer diameter after rolling together.

According to a further exemplary embodiment of the internally cooled valve is the Valve stem and valve head with the valve base formed from one piece of metal. The cavity is closed by a valve stem end which is connected to the valve stem by welding, preferably friction welding. In this embodiment, the valve body is made from a cylindrical or cup-shaped semi-finished product by drop forging, deep drawing and tapering. With several forming steps and stress-relieving annealing, a large cavity can be created in a valve head without the need for milling and closing the valve head with a valve cover. For this purpose, starting from a cup-shaped preform, a valve head and a cavity with a large diameter are formed by pressing and extrusion processes. In the following steps, an upper part of the cup-shaped molding is reduced in diameter by tapering, for example by stretching, transverse, round transverse rolling, flat-jaw transverse rolling, hammering or pulling (each with or without a core) and lengthened so that a shaft is created in several steps . The taper also increases the length of the shaft, while the cavity is retained by using a core or dome. The coolant sodium can then be introduced into the cavity of the one-piece valve body formed in this way from the shaft end of the compensating duct which is still open at the top. In a final step, the stem can then be connected to a valve stem end by “full-on-pipe” friction welding (or another welding process), thus closing the cavity.

According to a further aspect of the present invention, an internal combustion engine is provided with one of the internally cooled valves described above.

The present invention is illustrated in more detail below with the aid of representations of exemplary embodiments. The figures are only schematic representations.

Figure 1 is a sectional view of a conventional internally cooled valve.

FIG. 2 shows an internally cooled valve according to the invention with a compensating duct in a sectional view.

FIGS. 3A to 3E show in a sectional view the mode of operation of the compensation channel during a closing process.

FIGS. 4A and 4B show the position of a compensation channel formed by a pipe in a sectional view. Figures 5A to 5G show possible fastenings and arrangements of equalizing duct tubes in the cavity. Figures 6A and 6B show embodiments of valves with a different structure of the valve body

Both in the description and in the figures, the same or similar reference symbols are used to refer to the same or similar components and elements. In order to keep the description as short and concise as possible, elements that have already been described in one figure are not described separately in further figures in order to avoid redundancy.

FIG. 1 shows a conventional internally cooled valve 22 with a valve stem 6 which ends at a lower end in a valve head 8 with a valve disk. The valve stem 6 ends at the top of the shaft to which the cone pieces attach the valve spring and to which the valve is controlled. Inside, the valve 22 is provided with a cavity 10 which is partially filled with a coolant 24. Sodium, which is present in a liquid state at operating temperatures of an internal combustion engine, is usually used as the coolant 24. Usually not the entire cavity but only 1/2 to 3/4 of the cavity of the valve is filled with sodium. It is also possible to fill only 1/4 or 1/3 of the cavity of the valve with sodium. During operation, the sodium moves up and down in the valve stem 6 or in the cavity 10 of the valve stem 6 and transports heat from the valve head 8 in the direction of the cooled valve stem 6. The sodium moves within the valve with each opening or closing process 22. The cavity 10 was created in the valve 22 by providing the valve head 8 with an opening on a valve disk surface. The cavity 10 was introduced into the valve disk 8 and the valve stem 6 through the opening. After the coolant 24 (here sodium) had been filled in, the opening was closed by a valve base or valve base cover 20. The base 20 or cover was joined to the valve disk by laser welding, electron beam welding, resistance welding or friction welding. The rear side of the valve head 8, which ends at the valve stem 6, has no joints in this embodiment, and the valve head can be manufactured in one piece with the valve stem 6, so that the risk of a valve disk or valve head being torn off can be minimized. Here, however, the problem arises during operation that the liquid coolant 24, when it wants to flow from the valve head in the direction of the worker, encounters a compressible gas which is located in the cavity 10. The long, narrow shape of the cavity 10 makes gas exchange more difficult and the sodium flows as it flows upwards like against an elastic spring which counteracts the movement of the coolant and thus the desired “shaker cooling”. The cavity is divided here into an essentially cylindrical shaft region or region of the shaft 14 and a head region or region of the valve head 12, which is also essentially cylindrical. The area of the valve stem 14 is prelate and has a small diameter d. The area of the valve head 14 is oblate and has a large diameter D. Between the area of the valve stem 14 and the area of the valve head 14 there is a transition area 18 which is funnel-shaped and tapers from the diameter D to the diameter d. A coolant 24 is arranged in the cavity. The coolant 24 has been illustrated using circles.

Figure 2 shows a simple embodiment according to the invention of an internally cooled valve 2 with a compensating channel 16 in a sectional view. The valve body 4 here also comprises a valve stem 6 and a valve head 8 and is provided with a cavity 10 which extends almost through the entire valve. The cavity 10 is wider in the head and narrower in the shaft. The cavity 10 is here arranged eccentrically in the shaft in order to provide space for a compensating channel 16 in the shaft. The compensation channel 16 is arranged in the valve 2 and extends between the area of the valve stem 14 of the cavity 10 as far as an area of the valve head 14 of the cavity 10. Here the channel opens near the worker and in an approach that extends to just before the valve base. When the valve is open, the coolant is around the valve head near the valve base.

The cavity 10 and the compensation channel 16 run essentially parallel in the valve stem 6. The compensation channel 16 opens with a shaft end of the channel 44 near a shaft end of the valve stem 6 into the cavity 10. The compensation channel 16 opens with a head end of the compensation channel 46 in a socket in the transition area 18 or the head area 12 of the valve head 8 in the cavity 10 When the valve is open or when the valves are stationary, the coolant is located in the cavity 10, as shown, and extends both in the cavity and in the equalizing channel 16, as is shown by the circles.

The illustration in FIG. 2 serves to clarify the principle of how the movement of the coolant in the valve stem can be improved, but the designs in FIGS. 2 and 3 are not the first choice with regard to manufacture and operation of the valve. FIGS. 3A to 3E show in a sectional view the mode of operation of the compensation channel during a closing process. FIG. 2 shows the situation at the end of a closing process shortly before the valve disk edge is placed on a valve seat of a cylinder head, with the coolant 24 still present in the head. The acceleration of the coolant corresponds to a direction towards the lower edge of the figure, and corresponds to the situation of a valve that stands with the plate on a flat surface and is subject to gravity.

FIG. 3A shows the moment when the edge of the valve disk is placed on a valve seat of a cylinder head. The acceleration of the coolant corresponds to a direction towards the valve stem 6. The illustration corresponds to the situation of a valve with the end of the valve standing on a flat surface and subjected to gravity. The coolant is still distributed exactly as in FIG. 2, and the fill level or the fill depth of the cavity 10 and the fill level or the fluid column of the coolant in the compensation channel 16 is essentially the same.

FIG. 3B shows a moment after the valve disk edge has been placed on a valve seat of a cylinder head. The coolant 24 has moved in the direction of the valve stem 6, and a vacuum or an area with low pressure has formed above the coolant, while a gas has formed in the The cavity below the coolant is compressed by the movement. The coolant fills the cavity 10 and the equalization channel 16 evenly. It could happen that the shape of the transition area results in a nozzle effect that accelerates the coolant 24 in the cavity 10 and thus creates a larger coolant column in the cavity 10 than in the equalization channel 16, which, however, only increases the effect of the present arrangement.

In FIG. 3B, the coolant still flows in the direction of the shaft and through the head end or the connecting piece 46 further into the compensation channel 16. In the compensation channel, the height of a fluid column increases even more.

In FIG. 3C, the neck or stub of the head end 46 of the compensation channel has broken through the surface of the coolant 24, and no further coolant 24 flows into the compensation channel 16. Since the compensation channel has a constant diameter, the height of the liquid column does not change from here on more. Further coolant 24 is moved into the shaft through the transition section and the funnel shape increases the coolant Liquid column in the cavity 10 continues, while a compressible gas is further compressed in the cavity 10 in the shaft.

In FIG. 3D, the reduction in the diameter in the transition region 18 of the cavity 10 increases the height of the fluid column hH in the cavity 10, while the height of the fluid column hA in the compensation channel 16 does not increase any further. The pressure within the compressible gas in the shaft area of the cavity is determined by the height of the fluid column hH and the acceleration and the density of the coolant. As long as both fluid columns hH and hA are of the same height, they contribute in the same way to the compression of the gas in the shaft. In Figure 3D, the pressure on the gas is dominated by the fluid column hH in the cavity. Since the cavity below the fluid columns is in communication, the pressure that the gas exerts on the two fluid columns will continue to increase. In FIG. 3E, the pressure in the gas has increased due to the increasing height of the fluid column hH in the cavity so that it has pushed the smaller fluid column hA in the equalization channel 16 up through the head end of the equalization channel into the head or transition area. As soon as the entire column of fluid has been pushed out of the compensation channel 16, the compressed gas can flow out of the shaft again into the head area and the transition area and thus relax. The coolant can continue to flow into the cavity as far as the end of the shaft without being hindered by the compressed gas. Here, the geometry of the cavity together with the compensation channel can prevent a compressible gas in the cavity from hindering the movement of a coolant 24.

The following FIGS. 4A to 5F are provided with a valve body, the valve head 8 and the valve stem 6 of which, with the exception of the valve stem end 26, are made in one piece. This valve body was produced from a cup-shaped semi-finished product by deep drawing and tapering and allows a large cavity to be created in a valve head through several forming steps without the need for milling and closing the valve head. In particular, a weakening of the valve in the area of the highly stressed parts such as the valve base and valve head can be dispensed with. Such a valve can be produced in that a cup-shaped preform is formed into a valve head with a cavity by pressing and extrusion processes, a wall of the cup later forming the valve stem. In the following several steps, an upper part of the cup-shaped molding, in particular the wall of the cup, is tapered and lengthened. When tapering, stretching, transverse, round transverse rollers, Flat jaw cross rolling, hammering or pulling, each with or without a core, are used. After the diameter of the cup wall is sufficiently reduced and the cup wall is lengthened in the axial direction, it forms a hollow valve stem. A tube, which forms the compensation channel and the coolant, can be inserted from the open end of the shaft into the hollow valve stem formed in this way. The cavity can then be closed by welding on a valve stem end by welding / friction welding seam 28. Figures 4A to 5F describe in particular different designs of the pipe or the equalization channel. FIGS. 4A and 4B show the position of an equalizing channel formed by a pipe in a sectional view. Instead of a channel in the shaft itself, in FIGS. 4A and 4B the channel is formed by a tube 40 which is arranged concentrically in the valve or in the cavity 10. FIGS. 4A and 4B do not show how the pipe is fastened in the cavity 10, since these figures only serve to define the position of the head end 46 of the pipe 40 which forms the compensating channel 16. In Figures 4A and 4B, the tube should not be able to move in the axial direction.

In FIG. 4A, the transition region 18 is shown divided into two halves by dashed lines. The tube 40, which forms the compensation channel, is shown in such a way that it ends in half hl / 2 of the transition area which is closer to the valve base.

In FIG. 4B, the transition area 18 is shown divided into three thirds by dashed lines. The tube 40, which forms the compensation channel 16, is shown in such a way that it ends in the third hl / 3 of the transition area that is closer to the valve base.

In FIG. 4A, the area 12 of the valve head is shown above the transition area. In FIG. 4B, the area of the valve head 12 is formed by the upper edge of the transition area. In FIGS. 5A to 5E, possible fastenings and arrangements of equalizing duct tubes in the cavity are shown. The coolant was not shown in FIGS. 5A to 5E.

FIG. 5A shows the pipe 40 which forms the compensation channel 16 in one on both sides

beveled shape. The bevels of the tube 40 allow the shaft end 44 or the head end 46 of the tube 40 to be kept open in a simple manner. In this form, for example, the head end 46 of the tube 40 can be welded to the valve base 20. The tube can also be attached to the shaft in other ways. The tube can also rest against one end of the cavity 10. It can also not be shown

Guide elements are used. The bevel ensures that the shaft end and the head end of the tube remain free even if the

Fixing of the tube 40 should loosen and the tube is exposed in the cavity.

In FIG. 5B, the tube is frictionally and positively fastened by conical structures of the cavity in the shaft end and the valve base 20; here, transverse bores are still necessary to ensure fluid entry and exit into the tube 40. The upper conical structure can be through a drill cone or the main cutting edge of a

Groove drill produced, which machined the shank end 26 before welding. The conical structure on the valve base 20 can be produced when the preform is reshaped. The pipe is in the radial directions by form fit and in

Circumferential direction held by frictional engagement. Due to the shape it is also possible to fasten the tube 40 to the shaft 8 and / or to the valve base 20 by friction welding,

for example, together with the friction welding of the valve stem end 26 on the

Valve stem.

In FIG. 5B, the equalizing channel 16 or the pipe ends in front of the transition area 18 in the valve head 8 close to a valve base 20.

Figures 5C and 5D illustrate embodiments in which the tubes 40 are slotted at their ends. In the embodiment of FIG. 5C, the tube 40 is arranged directly on the wall of the cavity 10. The tube is attached to the bottom of the valve base 20 by welding and can be inserted into a form-fitting attachment at the top. As a result of the form fit, the tube 40 can expand and contract in the longitudinal direction. The tube 40 reduces a uniform distribution of the coolant in the circumferential direction, but this has little or no effect due to the small dimensions of the tube. This embodiment is aimed at further intensifying the effect according to the invention through a capillary action of the coolant. Liquid sodium, like mercury and steel, has a relatively high surface tension. The high surface tension creates a

Capillary depression expected. Thus, under operating conditions, a smaller column of liquid will form in the tube 40 in comparison with FIGS. 2 and 3A to 3E, whereby the inventive effect is further intensified. By arranging the tube 40 at the edge of the cavity, the capillary effect in the cavity is further reduced. The capillary effect is proportional to the inverse of the diameter. By arranging the tube 40 eccentrically at the edge of the cavity 10, the capillary effect is further reduced there, and the function of the compensation channel 16 or the pipe is further improved.

FIG. 5D shows an embodiment in which the tube 40 is arranged only slightly eccentrically in order to reduce uneven heating of the shaft and at the same time the

Reduce capillary effect in the cavity outside the tube 40. Here can the

Shaker cooling can be improved significantly, even if not overall

rotationally symmetrical valve is used. Due to the small distance between the tube 40 and the inner wall of the cavity on the left-hand side, the coolant can still be cooled through the entire inner surface of the shaft, as a result of which bending of the shaft due to thermal expansion can be avoided.

FIG. 5E shows a tube which is provided with an angle or a bend on a lower head end 46 facing the valve base 20. As a result of the bend, a larger area can be provided for connection to the valve base 20. The upper shaft end 44 of the tube 40 is provided with a bevel. The

The pipe is also provided with centering elements 42 which can hold the pipe in the middle or slightly offset in the cavity of the valve. In the embodiment of FIG. 5E, the tube 40 can simply be inserted into the cavity from the shaft end and fixed in the cavity 10 by frictional engagement.

In FIG. 5F, the valve from FIG. 5B is shown, which is additionally filled with a coolant. Before the end of the shaft is welded on, the sodium is inserted into the cavity 10 together with the tube 40 which forms the compensation channel. Since the sodium is in a solid state at room temperature, it can easily be introduced into the cavity in the form of sodium sand before or after the pipe of the equalization duct is inserted. However, it is also possible to use the pipe

Compensating channel forms into which sodium is to form the coolant filling

pour in and insert the tube 40 together with the sodium 24 into the shaft. This would also have the advantage that the tube can be centered in the cavity by the solid sodium, so that it is ensured that the tube is aligned with the corresponding guide retaining elements in the cavity. As soon as the valve warms up for the first time during operation, the sodium melts and the pipe can continue through

Form fit are kept in the valve. However, it is also possible to partially fill the valve with the sodium before closing, and then to drill out the partially filled head or the partially filled shaft so that the tube, which is to serve as a compensation channel, can be inserted into the bore in the sodium .

Finally, of course, there is also the option of combining the sodium in one Centrifugal casting process is mainly poured into the cavity of the valve head and allowed to solidify there. Then the tube which forms the compensation channel can then be inserted into the shaft and welded either at the shaft end 26 or on the inside of the valve base 20. The valve can then be closed by conventional welding methods such as friction welding, for example, on one of the weld seams 28 between the valve stem 6 and the valve stem end 26.

In FIG. 5G, a valve is shown in which the valve head 8 and the valve stem 6, with the exception of the valve stem end 26, are made in one piece. This valve body was produced from a cup-shaped semi-finished product by deep drawing and tapering and allows a large cavity to be created in a valve head through several forming steps without the need for milling and closing the valve head. For this purpose, starting from a cup-shaped preform by pressing and

F 1 extrusion process a valve head and a cavity formed with a large diameter. In the following steps, an upper part of the cup-shaped molding is reduced in diameter by tapering, for example by stretching, transverse, round transverse rolling, flat-jaw transverse rolling, hammering or pulling (each with or without a core) and lengthened so that a shaft is created in several steps. The taper also increases the length of the shaft while maintaining the cavity by using a core or mandrel. In the so formed cavity of the one-piece

The valve body, the pipe 40 that forms the compensation channel and sodium (not shown) was introduced by the still open worker. In a final step, the stem was sealed with a valve stem end by "full-on-pipe" friction welding. It should turn out that the friction weld is creating in some way

is problematic, the creator of the molding can be tapered less sharply, and can be closed by a final forming process. Here can

Creators are simply pressed together by rolling in the radial direction so that the cavity is closed. FIG. 6A shows a pipe which is provided with an angle or a bend at a lower head end 46 facing the valve base 20. As a result of the bend, a larger area can be provided for connection to the valve base 20. The upper shaft end 44 of the tube 40 is provided with a bevel. The tube is also provided with centering elements 42 which can hold the tube in the center or slightly offset in the cavity of the valve. In the embodiment of FIG. 5E, the tube 40 can simply be inserted into the cavity from below and fixed in the cavity 10 by frictional engagement. In the figure 6A a valve is shown, the valve body of four parts

is composed. The valve head comprises a valve cover 20 of the bottom in the

Valve bottom is inserted and is fastened by a weld 28. The valve head 8 is connected to the valve stem 6 by a welded connection 28. The valve stem 6 is also connected to a valve end 26 by a welded connection 28. The present valve can be used in a desired or advantageous manner

be assembled in that the valve cover 20 is connected to the valve base, then the valve stem 6 is connected to the valve head 8 by welding, and finally the valve end 26 is welded to the valve stem 6. However, other sequences of the welded connections are also possible. Preferably, however, the valve base is first inserted into the valve head, and then the stem is welded to the valve stem end or the valve head. Preferably before attaching the last one

Weld the sodium 24 together with the tube 40 that forms the compensation channel inserted into the cavity.

The embodiment in FIG. 6B corresponds to FIG. 5G and has been modified to the effect that the weld seam between the valve head and the valve stem is omitted, but rather on the

Valve bottom is arranged. Here, the cavity 10 in the head 8 is first worked out by milling, then the shaft 6 is drilled out in the longitudinal direction. Subsequently it is possible to use the compensation channel or the pipe that forms the compensation channel and sodium as

Bring coolant from the valve head still open into the cavity. The cavity of such a valve blank can then be closed at the bottom by a valve cover 20 which is attached to the valve base by a “top of head” weld.

It is also provided to combine all the individual features of the figures to form further embodiments, for example different types of fastening of the tube 40 in the cavity 10 can be combined. It is also possible to combine or interchange different end shapes of the ends of the pipe and head ends of the pipe. Combinations of different elements and components, each of which are only shown in individual versions, are also to be regarded as disclosed. It is provided, for example, to combine the shaft shapes of FIGS. 6A and 6B also with one of the designs of the compensation channels of FIGS. 4A to 5G. It is also provided that the shaft shapes of FIG. 6A are designed with fewer, for example, only two weld seams or only one weld seam. It is also planned to apply the weld at a completely different location. List of reference symbols

2 internally cooled valve

4 valve bodies

6 valve stem

8 valve head

10 cavity

12 Area of the valve head

14 Area of the valve stem

16 compensation channel

18 Transition area of the diameter in the cavity

20 valve bottom

22 conventional internally cooled valve

24 coolant

26 valve stem end

28 welds / friction welds

40 tube that forms the compensation channel

42 centering elements

44 Shaft end of the tube / compensation channel

46 Head end of the pipe / compensation duct

A axial direction

d Diameter of the cavity in the area of the valve stem

D diameter of the cavity in the area of the valve head hH fluid column of the coolant in the cavity

hA fluid column of the coolant in the equalization channel hl / 2 half of the transition area

hl / 3 thirds of the transition area

R radial direction

Claims

Expectations

1. Internally cooled valve (2) comprising:

a valve body (4) with a valve stem (6) and a valve head (8), wherein in the valve body (4) a cavity (10) extends from the valve stem (6) into the valve head (8), the cavity ( 10) has a larger diameter (D) in the area of the valve head (12) than in an area of the valve stem (14), characterized in that

a compensation channel (16) is arranged in the valve (2) which extends between a region of the valve stem (14) of the cavity and into a region of the valve head (14) of the cavity (10).

2. Internally cooled valve according to claim 1, wherein the cavity (10) has a

Transition area (18) comprises, in which the diameter of the cavity (10) changes, and wherein the compensation channel (16) in one half (Hl / 2) of the

Transition area (18) ends in the valve head (8), which further lies on a valve base (20).

3. internally cooled valve according to claim 2, wherein the cavity (10) a

Transition area (18) comprises, in which the diameter of the cavity (10) changes, and wherein the compensation channel (16) in a third of the

Transition area (18) ends in the valve head (8), which is further on a valve base (20).

The internally cooled valve of claim 1, wherein the cavity (10) is a

Transition area (18), in which the diameter of the cavity (10) changes, the compensation channel (16) ending in front of this transition area (18) in the valve head (8) close to a valve base (20). 5 Internally cooled valve according to one of claims 1 to 4, characterized in that the compensation channel (16) runs parallel to an axial direction (A) of the valve body (4)

6 Internally cooled valve according to one of Claims 1 to 5, characterized in that the compensating duct (16) is tubular.

7. Internally cooled valve according to claim 6, characterized in that the Compensating channel (16) is formed by a tube (40).

8. Internally cooled valve according to one of the preceding claims, characterized

characterized in that the cavity (10) is essentially rotationally symmetrical.

9. Internally cooled valve according to claim 7 or 8, characterized in that the tube (40) runs essentially coaxially to the cavity (10) or to the valve stem (6).

10. Internally cooled valve according to claim 7 or 8, characterized in that the tube (40) runs essentially on the edge of the cavity (10).

1 1. Internally cooled valve according to claim 7 to 10, characterized in that the tube (40) is beveled at at least one end.

12. Internally cooled valve according to claim 7 to 1 1, characterized in that the tube (40) has an angle at at least one end.

13. Internally cooled valve according to claim 7 to 12, characterized in that the tube (40) is welded at at least one end to an inner side of the cavity (10).

14. Internally cooled valve according to claim 7 to 13, characterized in that the tube (40) is clamped at at least one end to an inside of the cavity (10).

15. Internally cooled valve according to claim 7 to 14, characterized in that the tube (40) is held at least at one end with an inside of the cavity (10) by a form fit.

16. Internally cooled valve according to claim 7 to 15, characterized in that the centering elements (42) are arranged on the tube (40), which hold the tube (40) coaxially to the cavity (10).

17. Internally cooled valve according to one of claims 1 to 16, characterized in that the valve stem (6) and the valve head (8) are made in one piece.

18. Internally cooled valve according to one of claims 1 to 17, characterized in that the valve stem (6), the valve head (8) with the valve base was formed in one piece from a piece of metal, wherein the cavity (10) through a

Valve stem end (26) is closed, which is connected by welding to the valve stem (6).

19. V combustion engine with an internally cooled valve according to one of the preceding claims 1 to 18.