solenoid valve

Abstract

In order to provide a solenoid valve (1) comprising a valve casing (2) in which an electric coil (3) and a magnetic armature (5) are arranged, and a valve member (8) operable in an axial operating direction by the magnetic armature (5) for opening and closing the solenoid valve (1), in which the valve stroke of the valve member (8) can be easily limited, the present invention provides that the coil (3) is arranged on a coil support (4), and that an end (4a) of the coil support (4) facing the magnetic armature (5) in the axial direction is formed as an end stop for the magnetic armature (5), thereby limiting the axial movement of the magnetic armature (5), the coil support (4) is made of plastic, and the coil (3) is at least partially integrated into the coil support (4).

Description

[Technical Field]

[0001] The present invention relates to a solenoid valve having a valve housing in which an electric coil and a magnetic armature are arranged, and a valve member operable by the magnetic armature in an axial operating direction for opening and closing the solenoid valve.The present invention also relates to an internal combustion engine.

[0002] Electromagnetically operated injection or spray valves are often used in internal combustion engines to supply liquid or gaseous fuel to the combustion chamber. These valves are commonly referred to as solenoid valves. Compared to conventional mechanically operated valves, solenoid valves offer the advantage of highly flexible valve control, independent of the engine's speed. For example, this allows for variable control of the opening time, opening duration, and valve stroke, thereby increasing the flexibility in metering fuel. Large engines, particularly large gas engines, often use the pre-chamber principle, in which gaseous fuel is supplied not directly to the combustion chamber but to a pre-chamber located upstream of the combustion chamber. In this case, the combustible gas / air mixture is ignited in the pre-chamber, typically via a spark plug and / or via compression. Combustion begins in the pre-chamber and spreads to the combustion chamber connected to it. In the installed state, the solenoid valve generally has at least one valve opening in the valve housing on the side facing the combustion chamber or pre-combustion chamber, which is closed by a valve element. By controlling the solenoid valve accordingly, the valve opening can be opened or closed as desired, so that a predetermined amount of fuel is introduced into the combustion chamber or pre-combustion chamber.

[0003] Such solenoid valves typically have a valve casing in which an electric coil is arranged that can be supplied with energy to generate a magnetic field. Furthermore, a movable magnetic armature is provided, which is usually movable axially of the solenoid valve by the generated magnetic field. A valve element is usually connected to the magnetic armature and operated by the magnetic armature. When the solenoid valve is operated by applying a voltage to the electric coil, the magnetic armature and the valve element connected to the magnetic armature move to open the valve opening, thereby injecting or spraying fuel into the combustion chamber or pre-combustion chamber. For this purpose, the fuel is usually pre-compressed to a predetermined pressure and supplied to the solenoid valve through an appropriate supply opening. A return spring is usually also provided in the solenoid valve, against which the magnetic armature is moved. After the solenoid valve is operated, the return spring acts to close the valve opening again even if the energy supply fails.

[0004] To limit the valve stroke, i.e., the stroke that the valve member can achieve, to a predetermined maximum value, a stroke limiting device is typically integrated into the valve, often in the form of one or more separate components. However, the disadvantage is that these stroke limiting devices require corresponding installation space within the valve, which is usually quite limited. Furthermore, the associated material and manufacturing costs result in additional costs, which is also disadvantageous. German Patent Application Publication No. 102012224240 discloses a solenoid valve with a magnetic assembly, which includes, for example, a coil, a magnetic core, and a magnetic armature cooperating with the magnetic core. The magnetic assembly is arranged on a support member, which includes an outer pole ring and an inner pole ring. The outer pole ring may have a step on its side facing the magnetic armature, which serves as an armature stop.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a solenoid valve which is constructed as simply and compactly as possible and whose valve stroke can be limited in an easy manner.

[0006] This object is achieved according to the invention by providing a coil on a coil support, the end of which axially faces the magnetic armature as an end stop for the magnetic armature, thereby limiting the axial movement of the magnetic armature to limit the valve stroke of the valve member, the coil support being made of plastic, and the coil being at least partially integrated into the coil support, for example at least partially filled with plastic. In this case, preferably the coil is fully integrated into the coil support, for example filled with plastic. This provides a simple means for limiting the valve stroke without requiring a separate component.

[0007] Preferably, the coil generates a magnetic flux that flows through the magnetic armature via the magnetically conductive outer wall of the valve casing during operation of the solenoid valve, and in this case, a magnetically conductive flux member is provided in the valve casing, and the flux member guides at least a portion of the magnetic flux that flows through the valve casing outer wall to the end face of the magnetic armature facing the coil, thereby reducing the lateral force acting on the magnetic armature and, as a result, reducing friction loss in the solenoid valve.

[0008] In order to guide the magnetic flux advantageously into the magnetic armature, the magnetic flux member is preferably arranged transversely to the operating direction between the valve housing outer wall and the end of the coil carrier and is arranged between the coil and the magnetic armature in the operating direction.

[0009] The flux member is preferably configured as a flux ring, particularly preferably as a closed flux ring, so that the magnetic flux can be introduced into the magnetic armature at any point in the circumferential direction. Furthermore, the flux ring can be easily manufactured.

[0010] Preferably, the magnetic flux member has a higher magnetic permeability than the valve casing outer wall, so that the magnetic reluctance is reduced and the maximum amount of magnetic flux can be introduced to the end face of the magnetic armature.

[0011] It has proven particularly advantageous if the flux element has a cross section in the shape of a trapezoid, preferably a right-angled trapezoid, since this allows a large contact surface to be formed with the outer wall of the valve housing.

[0012] Advantageously, the valve casing forms a cylinder in the region of the magnetic armature, the magnetic armature forming an axially movable piston in the cylinder, a compression chamber being formed between a first armature end face facing away from the coil and the opposite valve casing wall in the operating direction, and at least one throttle opening is arranged in the magnetic armature, connecting the first armature end face with the opposite second armature end face, thereby forming a pneumatic damper that reduces the speed at which the valve member contacts the valve seat.

[0013] Preferably, a seal member for sealing the compression chamber is disposed on the circumferential surface of the magnetic mover, thereby improving the damping effect.

[0014] Preferably, a valve opening is provided at an axial end of the valve housing, which is provided with at least one supply opening for a preferably gaseous medium, which supply opening is connected to the valve opening inside the valve housing, so that the solenoid valve can be used advantageously as a gas injection valve for an internal combustion engine.

[0015] Preferably, the magnetic armature has an armature shaft, and the valve member has a valve shaft separate from the armature shaft, in which case the magnetic armature operates the valve shaft via the armature shaft when the solenoid valve is operating, thereby decoupling the movement of the magnetic armature from the valve member when the solenoid valve is closing, thereby reducing wear on the valve member and valve seat.

[0016] Preferably, a buffer element made of plastic is arranged between the armature shaft and the valve shaft, which prevents direct contact between the armature shaft and the valve shaft, thereby reducing noise and wear.

[0017] In order to reduce the friction losses of the solenoid valve, the buffer element is advantageously made from a tribologically optimized plastic, preferably a plastic containing polytetrafluoroethylene (PTFE).

[0018] Preferably, a spring element is arranged in the valve casing, which exerts a restoring force on the valve element, thereby keeping it in a closed position when the solenoid valve is in a deactivated state, thereby ensuring that the valve is closed as soon as the coil is deenergized.

[0019] The object is furthermore achieved by an internal combustion engine having a cylinder head and at least one combustion chamber, in which at least one solenoid valve according to the invention is arranged for supplying a fuel, preferably in gaseous form, to the combustion chamber or to a pre-combustion chamber arranged upstream of the combustion chamber.

[0020] The invention will now be explained in more detail with reference to FIG. 1, which shows, by way of example, schematic and non-limiting example, one advantageous configuration of the invention. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of an electromagnetically operable actuator in the form of a valve;

[0022] FIG. 1 shows one advantageous configuration of a solenoid valve 1 according to the invention. The solenoid valve 1 shown is designed as a dry solenoid valve 1 and is intended to inject gaseous fuel into a combustion chamber or a pre-combustion chamber arranged upstream of the combustion chamber of an internal combustion engine (not shown). The solenoid valve 1 has a valve casing 2, which here is substantially cylindrical and has a valve axis A. To the left of the valve axis A, the solenoid valve 1 is shown in a closed state, and to the right of the valve axis A, it is shown in an open state. A first axial end E1 of the valve casing 2 is provided with a mounting part B, here in the form of a screw thread, by means of which the solenoid valve 1 can be mounted to a cylinder head (not shown) of the internal combustion engine. Of course, other types of mounting are also possible.

[0023] An electric coil 3 is provided within the valve casing 2 and extends in an annular manner around the central valve axis A. Energy in the form of a voltage or current can be supplied to the coil 3 via a suitable electrical connection (not shown), which generates an (electro)magnetic field in a well-known manner. Depending on the structural design of the solenoid valve 1, the connection can be located, for example, on the radially outer side of the valve casing 2 or on a second axial end E2 of the valve casing 2 opposite the first axial end E1. However, the coil 3 does not have to be formed as a single piece, but can instead consist of several electrically connected coil segments distributed in a circular arrangement around the valve axis A.

[0024] The coil 3 is arranged in the coil support 4, which here, like the coil 3, is formed in a substantially annular shape and is arranged in an annular opening provided in the valve casing 2. The coil support 4 is made of a suitable plastic according to the invention and is therefore substantially non-magnetically conductive. This essentially means that the magnetic conductivity of the coil support 4 is negligibly small compared to the other parts forming the magnetic circuit M. The coil 3 is at least partially integrated into the coil support 4, so that the coil 3 is at least partially surrounded by the coil support 4. However, the coil 3 may also be entirely integrated into the coil support 4, for example by pouring plastic around the coil 3, so that only the electrical connections (not shown) of the coil 3 are appropriately routed out of the coil support 4. The coil 3 and the coil support 4 therefore preferably form a common component.

[0025] A magnetic armature 5 is also arranged in the valve casing 2, movable in the axial operating direction along the valve axis A. The magnetic armature 5 magnetically cooperates with the coil 3 to operate the valve and has an armature end face 5A facing the coil 3. In the illustrated example, the magnetic armature 5 is substantially cylindrical and has a first axial armature end face 5A facing away from the coil 3, an opposite second armature end face 5B facing the coil 3, and an armature circumferential surface 5U. A central cylindrical armature shaft 6 is arranged in the magnetic armature 5, for example, on the second armature end face 5B in the illustrated example. The armature shaft 6 is axially guided in a cylindrical opening in the valve casing 2 and is axially movable simultaneously with the magnetic armature 5. The armature shaft 6 may be formed integrally with the magnetic armature 5 or may be connected to the magnetic armature 5 in another suitable manner.

[0026] A valve opening 9 is further arranged in the valve casing 2 of the solenoid valve 1, here at the first axial end E1 of the valve casing 2. The valve opening 9 can be opened and closed via a valve member 8 operable by the magnetic armature 5. The valve member 8 is connected to a substantially cylindrical valve stem 7, which extends along a valve axis A inside the valve casing 2. The armature stem 6 and the valve stem 7 may be rigidly connected to each other, for example formed as a single unit. However, they are preferably formed as separate components, which allows the movement of the armature stem 6 to be decoupled from the movement of the valve stem 7, as will be explained in more detail below. The illustrated solenoid valve 1 also includes a spring 11 arranged in the valve casing 2. The spring 11 applies a return force to the valve stem 7 and the valve member 8 connected to it, so that when the solenoid valve 1 is in a non-operated state, the valve member 8 returns to a closed position (to the left of the valve axis A in FIG. 1 ) and closes the valve opening 8.

[0027] To operate the solenoid valve 1, a current or voltage is applied to the coil 3, which generates a magnetic flux. The magnetic flux exerts an electromagnetic attractive force on the magnetic armature 5, which moves the magnetic armature 5 in the operating direction against the spring force of the spring member 11 toward the coil 3. In this case, the armature stem 6 connected to the magnetic armature 5 presses against the valve stem 7, thereby moving the valve member 8 from a closed position (left side of the valve axis A) in which the valve opening 9 is closed to an open position (right side of the valve axis A) in which the valve opening 9 is opened, as indicated by the downward arrow along the valve axis A in FIG. 1 . The available distance between the closed and open positions is also referred to as the valve stroke.

[0028] As soon as the energy supply to the coil 3 is interrupted or the restoring force of the spring element 11 (possibly assisted by the pressure in the combustion chamber acting on the underside of the valve element 8) reaches a sufficiently low level that it overcomes the magnetic attractive force of the coil 3, the valve element 8 returns from the open position to the closed position, as indicated by the upward arrow along the valve axis A in FIG. 1 . Of course, by controlling the coil 3 accordingly, the valve stroke can also be infinitely controlled or adjusted, so that multiple valve positions between the closed and open positions can also be realized. For example, it is conceivable that the valve stroke can be infinitely controlled or adjusted depending on the applied coil voltage or coil current. This makes it possible, for example, to infinitely adapt the flow rate of a fuel, preferably gaseous, to a predetermined set combustion process.

[0029] The valve member 8 has a substantially conical valve plate 8a, which in the closed position (shown to the left of the valve axis A) sealingly abuts against a valve seat in the valve casing 2. In the open position (shown to the right of the valve axis A), the valve member 8 is lifted from the valve seat in the operating direction, freeing a predetermined cross-section of the valve opening 9. This allows a preferably pre-compressed medium, such as a gaseous fuel, to flow through a supply opening 10, which is arranged at the side of the valve casing 2 here, as indicated by the arrow in FIG. 1 , through the interior of the valve casing 2 and toward the valve opening 9. Of course, multiple supply openings 10 may also be provided. The medium can be supplied to the supply opening 10, for example, from a reservoir (not shown). Via the valve opening 9, the medium, for example, a fuel, can be supplied, for example, to a combustion chamber or pre-combustion chamber of an internal combustion engine (not shown).

[0030] In the illustrated example, the valve member 8 closes the valve seat from the outside. However, the opposite variant is also possible, in which the valve member 8 is arranged entirely within the valve casing 2 and closes the valve seat from the inside, for example, as in a well-known needle valve. The valve seat does not have to be arranged directly on the valve casing 2, but can instead be formed, for example, by a separate valve seat element arranged on the valve casing 2. This advantageously allows different materials to be used for the valve casing 2 and the valve seat element. Since the valve seat is a relatively highly mechanically loaded area due to the closing movement of the valve member 8, a valve seat ring made of a suitable, low-wear material, such as hardened steel, can be used as the valve seat element. In this case, it is advantageous to use a less expensive material for the remaining valve casing 2.

[0031] The spring element 11, which preloads the valve element 8 in the closed position toward the valve seat, is here in the form of a coil spring, which annularly surrounds the valve stem 7. The coil spring is arranged in a space provided for the coil spring in the valve casing 2, through which the gaseous fuel also flows. A shoulder is formed on the valve stem 7, and a disk is arranged on the shoulder. The coil spring is arranged axially between the disk and a step in the valve casing and applies a spring force axially, here upward, to the valve stem 7. Of course, other suitable spring elements 11, such as disc springs, may also be used, and the spring element 11 may have a non-linear spring characteristic curve, for example, a progressive or regressive spring characteristic curve, in order to influence the opening characteristic of the solenoid valve. Of course, it is to be understood that the illustrated configuration is merely exemplary, and other configurations of the solenoid valve 1 are also possible.

[0032] The valve stem 7 and the valve member 8 are manufactured from a material suitable for the anticipated temperatures, forces and pressures that occur during operation of the solenoid valve 1. If a metallic material is selected, this material should also be sufficiently corrosion-resistant to the media in which the solenoid valve 1 is intended to be used, such as gaseous fuels.

[0033] When the electric coil 3 is energized, a magnetic flux is generated that forms a magnetic circuit M. As shown in FIG. 1, the magnetic circuit M is closed via the valve casing 2 and the magnetic armature 5. This causes a magnetic force to act on the magnetic armature 5, which is attracted axially toward the coil 3, thereby opening (or conversely closing) the valve member 8. The magnetic flux of the magnetic circuit M here runs essentially axially through the first valve casing part 2a, radially inside the coil 3, and then axially below the coil 3, through the second valve casing part 2b, which extends radially outward from the first valve casing part 2a. The magnetic flux then runs from the second valve casing part 6b through the radially outward third valve casing part 6c, which simultaneously forms the outer valve casing wall of the valve casing 2. The magnetic circuit M is finally closed via a movable magnetic armature 5, which in the illustrated example is arranged axially above the coil 3. The coil 3 including the coil support 4 is thus mounted here in an annular recess formed radially between the first and third valve casing parts 6a, 6c.

[0034] The valve casing 2 consists of a magnetically conductive material, for example a ferromagnetic metal, at least in the region around the coil 3 where the magnetic circuit M is formed. Preferably, however, the entire valve casing 2 is made of the same ferromagnetic material, which simplifies the manufacture of the valve casing 2. Similarly, the magnetic armature 5 also consists of a magnetically conductive material, at least in the region of the magnetic circuit M, in order to close the magnetic circuit M. Preferably, however, the entire magnetic armature 5 is made of the same material, which simplifies the manufacture.

[0035] Preferably, however, the armature shaft 6 is non-conductive at least in the region of the magnetic circuit 5 in order to prevent undesirable lateral magnetic forces from being generated towards the armature shaft 6, which could potentially negatively affect the operating force of the valve member 8, for example by increasing friction. The solenoid valve 1 is configured as a so-called dry valve, i.e., no separate lubricant is provided for lubricating the moving parts of the solenoid valve 1. An advantage of such a dry valve, particularly when a relatively dry gas is used as fuel, is that friction between the armature shaft 6 and the part of the valve casing 2 in which the armature shaft 6 is guided (here, the first casing part 6a) is minimized. To achieve this, it is therefore advantageous, particularly in dry valves, for there to be no or minimal lateral forces acting on the magnetic armature 5 and the armature shaft 6 in order to reduce friction in the guiding of the armature shaft 6.

[0036] Preferably, therefore, at least one magnetically conductive flux element 12 is arranged in the valve casing 2, which guides at least a portion of the magnetic flux of the magnetic circuit M, which flows through the magnetically conductive valve casing outer wall, here the third casing part 2c, to the second armature end face 5B of the magnetic armature 5 facing the coil 3 (or in the opposite direction, depending on the direction of the magnetic flux). Preferably, at least 80%, particularly preferably at least 90%, and in particular 100% of the magnetic flux is introduced into the magnetic armature 5 via the flux element 12. The flux element 12 is arranged in this case in the radial direction, i.e., transversely to the operating direction, in the region of the valve casing 2 adjacent to the valve casing outer wall 2c. The flux element 12 extends radially inward from the valve casing outer wall 2c within the valve casing 2. In the operating direction, the flux element 12 is arranged between the coil 3 and the magnetic armature 5.

[0037] The use of the flux member 12 allows a larger amount of magnetic flux to flow axially into the magnetic armature 5, or reduces the amount of magnetic flux flowing radially from the valve casing outer wall 2c into the magnetic armature 5. This reduces the lateral force acting on the magnetic armature 5, thereby reducing the frictional force between the armature shaft 6 and the valve casing 2. This reduction in frictional losses further increases the operating speed of the valve member 8, thereby achieving highly dynamic opening and closing operations. In this case, it is particularly advantageous if the flux member 12 has a higher magnetic permeability than the valve casing outer wall 2c. This reduces the magnetic reluctance of the appropriate magnetic circuit, thereby increasing the amount of magnetic flux flowing through the flux member 12 to the armature end face 5B.

[0038] The arrangement of the flux element 12 can advantageously be used to reduce the radial extension of the solenoid valve 1, for example, the diameter of the valve casing 2, without substantially changing the operating force of the valve element 8. This is because the magnetic armature 5 can be made smaller in the radial direction. Alternatively, the operating force of the valve element 8 can be increased for a solenoid valve 1 of the same overall size. At the same time, the efficiency of force generation is improved, so that a smaller-sized coil 3 can be used, if necessary. Preferably, the flux element 12 in the illustrated example is configured as a closed flux ring, which is arranged radially between one end 4a of the coil carrier 4 and the outer wall 2c of the valve casing. In the axial direction, the flux ring 12 is arranged between the coil 3 and the magnetic armature 5. The flux element 12 is preferably made of a material with good magnetic permeability, for example, the same material as the magnetic armature 5 and / or the valve casing 2 or the magnetically permeable parts of the valve casing 2.

[0039] According to the invention, the end 4a of the coil support 4 facing the magnetic armature 5 in the axial direction is configured as an end stop for the magnetic armature 5. This makes it possible to limit the axial movement of the magnetic armature 5 in order to limit the valve stroke of the valve member 8. In the illustrated example, the flux member 12 is arranged radially between the end 4a of the coil support 4 and the valve casing outer wall 2c. The flux member 12 is arranged here so as to be substantially flush with the inner step of the valve casing outer wall 2c and with the axial end face of the first casing part 2a facing the magnetic armature 5. As shown in FIG. 1, the end 4a of the coil support 4 protrudes from the end face by a predetermined length l. Since this length l can be set by the structural configuration of the coil support 4, including the end 4a, the valve stroke can be easily limited without the need for a separate component. In this case, the entire coil support 4 or at least the end 4a may be made of a suitable material, in particular plastic, with specific spring and / or damping properties, for example, which can reduce the noise generated when the magnetic mover 5 hits the end 4a and the mechanical load on the magnetic mover 5 and the end 4a. This is advantageous for reducing noise generation and increasing the service life.

[0040] When the valve element 8 returns from the open position to the closed position after operation of the solenoid valve 1, the valve element 8 normally abuts against the valve seat due to the restoring force of the spring element 11. This can lead to undesirable noise generation and, on the one hand, to increased mechanical loads on the valve element 8 and the valve seat, which can lead to increased wear on the valve element 8 and / or the valve seat. This is particularly true for spring elements 11 with a high restoring force, which is favorable for high closing speeds. To prevent this, in another advantageous configuration of the solenoid valve 1, the solenoid valve 1 is equipped with a pneumatic damping means. For this purpose, the valve casing 2 forms a cylinder in the area of the magnetic armature 5, which forms an axially movable piston within the cylinder. In the operating direction, a compression chamber KR is formed between the first armature end face 5A of the magnetic armature 5 facing away from the coil 3 and the opposite valve casing wall 2d of the valve casing 2. At least one throttle opening 13 is further arranged in the magnetic armature 5, connecting the first armature end face 5A to the opposite second armature end face 5B. A suitable seal, for example, a well-known piston seal ring or O-ring, is preferably arranged on the circumferential surface 5U of the magnetic armature 5 to seal the compression chamber KR. Preferably, a pressure relief opening, in particular a pressure relief hole, is also provided in the valve casing 2, as shown in FIG. 1, connecting the space below the magnetic armature 5 to the space in which the spring element 11 is arranged. This allows pressure relief in the space below the magnetic armature 5 to avoid damping of the movement of the magnetic armature 5 even when the solenoid valve 1 is open. For good pressure relief, the pressure relief hole is preferably aligned with the throttle opening 13.

[0041] This allows for simple and efficient damping of the magnetic armature 5 when the solenoid valve 1 is closed. The damping characteristics can be influenced by the structural design of the solenoid valve 1, particularly the size of the first armature end face 5A, the volume of the compression chamber KR, the effectiveness of the sealing of the magnetic armature 5 within the cylinder, and the number, extent, and cross-section of the throttle openings 13. Pneumatic damping allows the speed at which the valve member 8 contacts the valve seat to be reduced, preferably to a maximum of 0.5 m / s, thereby reducing noise and wear. The damping characteristics are preferably selected so that the valve member 8 operates essentially undamped at the beginning of the closing movement and only becomes damped immediately before the closed position. This allows for rapid closing of the solenoid valve 1 while still achieving the softest possible contact with the valve seat. Rapid opening and closing of the solenoid valve 1 is advantageous for achieving the most accurate metering of the gaseous medium possible and for enabling multiple successive opening and closing movements to be performed in a short period of time.

[0042] Conventionally, the armature shaft 6 and the valve shaft 7 have often been firmly connected to each other, for example, by being integrally formed or welded. In particular, in the case of a relatively large solenoid valve 1 used in a large engine, the moving components of the solenoid valve 1, particularly the magnetic armature 5, the armature shaft 6, the valve shaft 7, and the valve member 8, have a relatively large mass, generating a non-negligible inertial force when the solenoid valve 1 is operated. Therefore, due to the mass of the magnetic armature 5 and the armature shaft 6, in particular, an inertial force may be generated that acts on the valve member 8 via the valve shaft 7 when the solenoid valve 1 is closed. In the illustrated example, when the valve member 8 abuts against the valve seat in the closed position, this inertial force generates an additional upward pulling force, which may have a negative effect on noise generation and wear of the valve member and / or valve seat.

[0043] Therefore, in another advantageous configuration of the solenoid valve 1, the armature shaft 6 and the valve shaft 7 are formed separately from each other, with a buffer element 15, preferably made of plastic, arranged between the armature shaft 6 and the valve shaft 7. This separate design allows the movement of the magnetic armature 5, including the armature shaft 6, to be decoupled from the movement of the valve member 8, including the valve shaft 7, during the closing operation. This reduces the load on the valve member 8 and the valve seat, because only the inertial force of the masses of the valve member 8 and the valve shaft 7 acts on the valve member 8 and the valve seat when the solenoid valve 1 is closed. The arrangement of the buffer element 15 also prevents direct contact, especially metal contact, between the armature shaft 6 and the valve shaft 7, thereby minimizing noise generation and wear on the contact surfaces.

[0044] The buffer element 15 is preferably made of a tribologically optimized plastic, such as a plastic filled with polytetrafluoroethylene (PTFE), so that there is minimal friction between the periphery of the buffer element 15 and the valve housing 2. This is particularly advantageous in dry valves without additional lubricants, since it further improves the efficiency and / or increases the operating force of the solenoid valve 1. If the end 4a of the coil support 4 serves as an end stop for the magnetic armature 5, as shown, the buffer element 15 can also be advantageously designed to compensate for any temperature-dependent changes in the valve stroke. For this purpose, a suitable material is used for the buffer element 15, and the buffer element 15 is dimensioned so that the (maximum) valve stroke when the magnetic armature 5 abuts against the end stop of the coil support 4 remains as constant as possible over temperature. In this case, it is sufficient for the compensation to be achieved at least within the temperature range to be expected for use of the solenoid valve 1.

[0045] Finally, it should be noted that the illustrated solenoid valve 1 is of course to be understood as merely exemplary and is shown in a simplified form to clarify its basic structure and functional form. The specific structural design, such as the dimensioning, material selection, and design of the valve member 8, are of course left to those skilled in the art and will depend on the field of use of the solenoid valve 1.

Claims

1. A solenoid valve (1) comprising a valve casing (2) in which an electric coil (3) and a magnetic armature (5) are arranged, and a valve member (8) operable in an axial operating direction by the magnetic armature (5) for opening and closing the solenoid valve (1), a solenoid valve (1) characterized in that the coil (3) is arranged on a coil support (4), and an end (4a) of the coil support (4) facing the magnetic armature (5) in the axial direction is formed as an end stop for the magnetic armature (5), thereby limiting the axial movement of the magnetic armature (5) to limit the valve stroke of the valve member (8), the coil support (4) is made of plastic, the coil (3) is entirely integrated within the plastic coil support (4), and when energy is supplied to the electric coil (3), a magnetic flux is generated that forms a magnetic circuit (M), and the magnetic circuit (M) is closed via the valve casing (2) and the magnetic armature (5).

2. 2. The solenoid valve (1) according to claim 1, wherein the coil (3) is surrounded by a plastic casting.

3. 3. The solenoid valve (1) according to claim 1 or 2, wherein the coil (3) generates a magnetic flux that flows through the magnetic armature (5) via a magnetically conductive valve casing outer wall (2c) of the valve casing (2) when the solenoid valve (1) is operated, and a magnetically conductive magnetic flux member (12) is provided within the valve casing (2), and the magnetic flux member (12) introduces at least a portion of the magnetic flux that flows through the valve casing outer wall (2c) to an armature end face (5B) of the magnetic armature (5) facing the coil (3).

4. 4. The solenoid valve (1) according to claim 3, wherein the magnetic flux member (12) is arranged between the valve casing outer wall (2c) and the end (4a) of the coil support (4) transversely to the operating direction and is arranged between the coil (3) and the magnetic armature (5) in the operating direction.

5. 5. The solenoid valve (1) according to claim 3 or 4, wherein the flux member (12) is preferably formed as a closed flux ring.

6. 6. The solenoid valve (1) according to claim 3, wherein the magnetic flux member (12) has a higher magnetic permeability than the valve casing outer wall (2c).

7. 7. The solenoid valve (1) according to any one of claims 3 to 6, wherein the flux member (12) has a cross section in the shape of a trapezoid, preferably a right-angled trapezoid.

8. 8. The solenoid valve according to claim 1, wherein the valve casing (2) forms a cylinder in the region of the magnetic armature (5), the magnetic armature (5) forming a piston axially movable in the cylinder, a compression chamber (KR) being formed between a first armature end face (5A) of the magnetic armature (5) facing away from the coil (3) and the oppositely positioned valve casing wall (2d) in the operating direction, and at least one throttle opening (13) is arranged in the magnetic armature (5), which connects the first armature end face (5A) with a second armature end face (5B) located on the opposite side.

9. 9. The solenoid valve (1) according to claim 8, wherein a seal member (14) for sealing the compression chamber (KR) is arranged on a peripheral surface (5U) of the magnetic armature (5).

10. 10. The solenoid valve (1) according to claim 1, wherein the axial end (E1) of the valve casing (2) is provided with a valve opening (9), and the valve casing (2) is provided with at least one supply opening (10) for a preferably gaseous medium, which supply opening (10) is connected to the valve opening (9) inside the valve casing (2).

11. 11. The solenoid valve (1) according to claim 1, wherein the magnetic mover (5) has a mover shaft portion (6), the valve member (8) has a valve shaft portion (7) separate from the mover shaft portion (6), and when the solenoid valve (1) is operated, the magnetic mover (5) operates the valve shaft portion (7) via the mover shaft portion (6).

12. 12. The solenoid valve (1) according to claim 11, wherein a buffer element (15) made of plastic is arranged between the armature stem (6) and the valve stem (7).

13. 13. The solenoid valve (1) according to claim 12, wherein the buffer element (15) is made from a tribologically optimized plastic, preferably a plastic containing polytetrafluoroethylene.

14. 14. The solenoid valve (1) according to claim 1, wherein a spring element (11) is arranged in the valve casing (2), and the spring element (11) applies a return force to the valve element (8), thereby keeping the valve element (8) in a closed position when the solenoid valve (1) is in a non-operating state.

15. 15. An internal combustion engine with a cylinder head and at least one combustion chamber, in which at least one solenoid valve (1) according to any one of claims 1 to 14 is arranged for supplying a fuel, preferably in gaseous form, to a combustion chamber or a pre-combustion chamber arranged upstream of the combustion chamber.

Images