Electromagnetic valve, especially for motor vehicles

Abstract

Electromagnetic valve (1), in particular for a gas cylinder for gas-powered motor vehicles, with - a main body (2); - a pressure sleeve (13) closed on one side, which is attached to the main body (2); - a coil (17) surrounding the pressure sleeve (13); - at least one anchor (22, 23) arranged in the pressure sleeve (13); - and at least one shut-off piston (9) which is axially displaceable in the pressure sleeve (13) and which has a main seal (10) which can be pressed against a main seal seat (11) of the main body (2); characterized in that the axially displaceable shut-off piston (9) and the pressure sleeve (13) have interlocking guide elements (25, 26) which guide the shut-off piston (9) against rotation on the pressure sleeve (13), wherein a first anchor (22) is pressed into the pressure sleeve (13) and a second anchor (23) is axially displaceably received in the pressure sleeve (13) between the first anchor (22) and the shut-off piston (13), wherein the second anchor (23) and the shut-off piston (9) have interlocking connecting elements which connect the second anchor (23) and the shut-off piston (9) against rotation, wherein the shut-off piston (9) has a connecting pin (29),the end of which, pointing towards the closed end of the pressure sleeve (17), has an enlarged pin head (35), wherein the second anchor (23) has a recess (36) for the pin head (35) and a passage area (30) for the connecting pin (29), wherein the pin head (35) engages edge sections of the passage area (30) in a form-fitting manner and wherein the connecting pin (29) is held in the passage area (30) in a rotationally fixed manner.

Description

[0001] The invention relates to an electromagnetic valve, in particular for a gas cylinder for a gas-powered motor vehicle, according to the preamble of claim 1.

[0002] Such electromagnetic valves are known, for example, from the publications EP 1 682 801 B1, DE 10 2013 019 877 A1, DE 10 2015 005 977 A1 and DE 10 2016 008 058 A1. The electromagnetic valves described here have a plunger with a pilot seal, which is lifted from a sealing seat on a piston by the movement of an armature due to a current flowing through a coil. This releases a flow through a pressure relief channel, also called a pilot bore, in the piston, thereby initiating the opening movement of the piston. With the piston open, gas can flow from a tank connection into the gas cylinder during refueling. During operation, gas can escape from the cylinder through the valve when the piston is open.

[0003] In all previously known electromagnetic valves, the moving elements, in particular the armatures and shut-off pistons which are slidable within a pressure sleeve, are rotationally symmetrical and housed in a cylindrical bore of the pressure sleeve. Especially during refueling, a gas at high pressure is supplied to the gas cylinder through the valve. This results in high flow velocities. The gas flow can cause the moving elements within the valve to rotate. Such rotations result in undesirable noise generation. The three German publications mentioned include locking pins intended to counteract such rotations. These pins require multi-part pressure sleeves or openings in the pressure sleeve, which can impair its sealing.

[0004] Publication US 5 188 017 A also shows a generic electromagnetic valve. Publication DE 10 2016 008 058 A1 shows a valve with an anti-rotation device that prevents the shut-off piston from rotating relative to the valve seat.

[0005] The object of the invention is to avoid undesirable noise generation in electromagnetic valves while ensuring optimal sealing. A further object is to achieve reliable valve operation.

[0006] To solve the problem, an electromagnetic valve with the features of claim 1 is proposed. Further advantageous features are described in the dependent claims.

[0007] According to the new development described here, an electromagnetic valve, especially for a gas cylinder for gas-powered motor vehicles, is proposed, which has, among other things, the following features: - a main body; - a pressure sleeve closed on one side, which is attached to the main body; - a coil surrounding the pressure sleeve; - at least one anchor arranged in the pressure sleeve; - and at least one shut-off piston which is axially displaceable in the pressure sleeve and which has a main seal which can be pressed against a sealing seat of the main body.

[0008] The axially displaceable shut-off piston and the pressure sleeve feature interlocking guide elements that prevent the shut-off piston from rotating within the pressure sleeve. This prevents the shut-off piston from rotating within the pressure sleeve and avoids unwanted noise. All of the anti-rotation elements are located within a closed pressure sleeve without any wall penetrations and therefore do not compromise the tightness of the high-pressure area inside the pressure sleeve. As described below, a first anchor is pressed into the pressure sleeve, and a second anchor is axially displaceable within the pressure sleeve between the first anchor and the shut-off piston and secured against rotation relative to the shut-off piston.

[0009] The guide elements for blocking piston rotation can be implemented in various ways. One possibility, for example, is to make the inner bore of the pressure sleeve non-circular and to give the outer contour of the shut-off piston a corresponding cross-section. If the receiving chamber for the shut-off piston has, for example, a triangular or rectangular cross-section, rotation of the shut-off piston is reliably prevented. However, the rotationally symmetrical shape of the components of the electromagnetic valve also has advantages. For example, it ensures a uniform pressure distribution across the components, which is desirable given the high pressures within the valve.

[0010] In rotationally symmetrical components, additional interlocking parts can also be used to block rotation between the shut-off piston and the pressure sleeve. In practice, the guide elements can include, for example, the following: - an axial groove; - a guide body; wherein the groove is arranged on one of the two mutually rotationally secured elements, namely pressure sleeve and shut-off piston, and wherein the guide body is arranged on the other of these two elements and projects into the groove.

[0011] The groove only needs to extend over a certain axial length, which corresponds at least to the axial relative movement between the shut-off piston and the pressure sleeve during operation of the electromagnetic valve. In practice, this length can be just a few millimeters. On the other hand, the length of the groove and the axial length of the guide body must be selected to ensure sufficient flexibility and ease of assembly. With a shut-off piston length of approximately 20 mm, the axial length of the groove and the connecting element is between 5 mm and 10 mm.

[0012] In practice, the groove can be arranged on the pressure sleeve, with the shut-off piston having a recess into which the guide body is inserted. In particular, the shut-off piston can have a head section and a base section, wherein the head section has a larger diameter than the base section and the recess is arranged in the base section.

[0013] This geometric shape of the shut-off piston is advantageous. The larger diameter of the head section allows the shut-off piston to accommodate a sufficiently large, annular main seal. At the same time, neither the shut-off piston nor the pressure sleeve requires an excessively large installation space.

[0014] In practice, the pressure sleeve can have a first inner diameter at its open end to accommodate the head section and a second inner diameter at the adjoining middle section to accommodate the base section, the second inner diameter being smaller than the first. The shoulder of the shut-off piston, which forms between the base section and the head section and corresponds to a step in the inner bore of the pressure sleeve due to the larger inner diameter for the head section, clearly defines the length by which the shut-off piston can be inserted into the pressure sleeve.

[0015] A first armature is pressed into the pressure sleeve, and a second armature is mounted in the pressure sleeve between the first armature and the shut-off piston, allowing axial displacement. The first armature, also called the core, can be made of a magnetizable material, such as stainless steel. This first armature is fixed in place by being pressed into the pressure sleeve. It cannot be displaced axially or rotated. The second armature, on the other hand, is mounted in the pressure sleeve, allowing axial displacement. It can be made of the same material as the first armature and is pushed away from the first armature by a helical spring, so that when the electromagnetic valve is de-energized, a gap exists between the first and second armatures. As soon as current flows through the coil, the gap closes because the magnetic forces attract the second armature towards the first.

[0016] The second armature and the shut-off piston feature positive-locking, interlocking connecting elements that prevent rotation between them. The first armature is secured against rotation by being pressed into the pressure sleeve. The shut-off piston is secured against rotation relative to the pressure sleeve by positive-locking guide elements. The axially movable second armature is itself secured against rotation relative to the shut-off piston, and thus relative to the pressure sleeve, by positive-locking, interlocking connecting elements. This anti-rotation mechanism for the moving parts of the electromagnetic valve reliably prevents unwanted noise during refueling.

[0017] In practice, the connecting elements can transmit an axial movement of the second armature to the shut-off piston. In particular, the connecting elements can be designed such that the second armature not only moves the pilot seal away from the pilot bore, but also moves the shut-off piston along with it, so that its main seal releases the gas flow in the electromagnetic valve.

[0018] The shut-off piston has a connecting pin, the end of which, facing the closed end of the pressure sleeve, has an enlarged pin head. The second anchor has a recess for the pin head and a passage for the connecting pin, wherein the pin head engages the outer edges of the passage in a form-fitting manner, and the connecting pin is held in the passage in a rotationally fixed position. The connecting pin can, for example, have flat side walls that abut against opposing flat side walls of the passage. This design not only ensures that the shut-off piston is driven by the second anchor, but also prevents the second anchor from rotating relative to the shut-off piston.

[0019] In practice, the pressure sleeve can be made of austenitic steel, preferably with a high nickel content. Such steel is particularly well-suited for valves used in hydrogen storage systems. It is resistant to embrittlement caused by hydrogen contact.

[0020] In practice, the pressure sleeve can be a single-piece component. A single-piece pressure sleeve offers improved sealing compared to a multi-piece pressure sleeve.

[0021] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show: Fig. 1 a longitudinal section through an electromagnetic valve described herein; Fig. 2 an enlarged longitudinal section of the pressure sleeve with coil and functional elements of the valve located therein Fig. 1; Fig. 3 A three-dimensional exploded view of the pressure sleeve, the armature and the shut-off piston of the valve from the Fig. 1 and Fig. 2; Fig. 4. A three-dimensional exploded view of the movable armature and the shut-off piston of the valve from the Fig. 1 and Fig. 2 in separate positions; Fig. 5 one of the Fig. 4 corresponding view of the movable anchor and the shut-off piston of the valve in the connected position.

[0022] In the Fig. Figure 1 shows that the electromagnetic valve 1 is arranged in a main body 2, also called the valve body. The main body 2 has a cylindrical section 3 with an external thread 4. The external thread 4 is designed to be screwed into an internal thread of a gas cylinder (not shown). The Fig. At the lower end of the cylindrical section 3, an injector 6 is arranged via a filter 5. Gas flows into and out of the gas cylinder through the injector 6. A main channel 7 leads to the injector 6 and, via a transverse channel 8, to an annular space surrounding the end face of a shut-off piston 9 of the valve 1. The main body 2 may include further fluid power components not shown in the drawings.

[0023] The main seal 10 is arranged on the front face of the shut-off piston 9, which is enlarged in Fig. 2. The main seal 10 interacts with an annular main seal seat 11, which seals the transverse channel 8 against a connecting channel 12. The connecting channel 12 leads to a distributor, which is connected on one side to a refueling line (not shown) through which the gas cylinder is refueled. On the other side, the distributor is connected to a consumer, e.g., an internal combustion engine or a fuel cell, to which the gas from the gas cylinder is routed during operation. The consumer is also not shown in the drawings.

[0024] In the closed position, the main seal 10 is pressed against the main seal seat 11, thus interrupting the fluid connection between the transverse channel 8 and the connecting channel 12. The closed position is both Fig. 1 as well as in Fig. 2. In the open position, the main seal 10 is pulled away from the main seal seat 11, thus releasing the aforementioned fluid connection.

[0025] The functional elements of the electromagnetic valve 1 are enclosed in a pressure sleeve 13. The pressure sleeve has a [missing information - likely a specific feature or characteristic] at the [missing information - likely a specific point or feature]. Fig. 1 and Fig. The right-hand, open end has an external thread 14 which is screwed into a complementary internal thread 15 of the main body 2. A sealing ring 16 seals the screw connection against the environment.

[0026] The pressure sleeve 13 is surrounded by a coil 17, which actuates the electromagnetic valve 1. When the coil 17 is de-energized, the valve 1 is in the position described in the Fig. 1 and Fig. 2 shown closed position.

[0027] Within the main seal 10, inside the shut-off piston 9, lies a pressure relief channel 18, also called a pilot bore, which is closed by the pilot seal 19. A plunger 20 presses the pilot seal 19 against a sealing seat at the left end of the shut-off piston 9. When the coil 17 is de-energized, a spring 21 at its left end pushes the plunger 20 towards the shut-off piston 9.

[0028] In the Fig. 1 and Fig. Figure 2 shows that two armatures 22, 23 are arranged in the pressure sleeve 13. The first armature 22, also called the core, is pressed into the left, closed end of the pressure sleeve 13. In other words, the outer diameter of the slightly tapered end of the first armature 22 is somewhat larger than the inner diameter of the tapered end section of the inner bore of the pressure sleeve 13. In practice, the pressure sleeve 13 can be made of austenitic steel with a high nickel content, which exhibits good resistance to hydrogen embrittlement. The first armature 22 can be made of a ferromagnetic material, particularly steel. The slight oversize of the end section of the first armature 22 results in an interference fit that secures the first armature 22 in the pressure sleeve 13 against rotation and axial movement.

[0029] To the right of the first anchor 22, that is, in the direction of the open end of the pressure sleeve 13, is the second anchor 23, which is axially movable within the inner bore of the pressure sleeve 13. Both anchors 22 and 23 have a cylindrical outer wall and are received in the cylindrical inner bore of the pressure sleeve 13. Both anchors 22 and 23 also have central bores. The plunger 20 extends through the bores in both anchors 22 and 23, and the spring 21, which pushes the plunger 20 towards the shut-off piston 9, extends into the bore in the first anchor 22. Fig. At the right end of the inner bore of the second armature 23, a radially inwardly projecting shoulder is provided, which ensures that the pilot seal 19 is not pushed out of the inner bore of the second armature 23. Thus, the second armature 23 is pushed towards the piston 9 via the free end face of the pilot seal 19 by means of the plunger 20, which is pushed to the right by the spring 21.

[0030] To open valve 1, the coil 17 is energized. This causes the second armature 23 to move towards the first armature 22 against the force of the spring 21 due to the electromagnetic force. This moves the pilot seal 19 away from the pilot seal seat 37. The high pressure from the main channel 7 and the cross channel 8 can flow through the pressure relief channel 18 to the connecting channel 12, thereby causing the shut-off piston 9 to move away from the main seal seat 11. This is described in more detail in EP 1 682 801 B1.

[0031] Details of the construction and the interaction of pressure sleeve 13, shut-off piston 9 and the two anchors 22, 23 are described in particular in the Fig. 3 - 5 to recognize.

[0032] The Fig. Figure 3 shows a three-dimensional exploded view of the pressure sleeve 13, the armatures 22 and 23, and the shut-off piston 9 of the valve 1. The pressure sleeve 13 is a hollow part in which Fig. 3. The component is closed at the left end. It has an external thread 14 at its right end. The first anchor 22 is inserted into the pressure sleeve 13, and its left, tapered end is pressed against the left end of the pressure sleeve 13. The second anchor 23 follows axially to the right of the first anchor 22. The shut-off piston 9 is located to the right of the second movable anchor 23. The shut-off piston 9 has a recess 24 into which a guide body 25 can be inserted. As in Fig. As can be seen in Figure 3, the contour of the guide body 25 corresponds to the contour of the recess 24. The guide body 25 can therefore be inserted into the recess 24 in a form-fitting manner. In the inserted state, the guide body 25 projects beyond the cylindrical contour of the shut-off piston 9. In particular, Fig. Figure 2 shows that a longitudinally extending groove 26 is arranged in the open end region of the pressure sleeve 13, in which the guide body 25 is inserted so as to be longitudinally displaceable. This ensures that the shut-off piston 9 cannot rotate relative to the pressure sleeve 13 during operation. Such rotational movement can be caused by the gas flow, particularly during refueling. The groove 26 and the guide body 25, which form positively interlocking guide elements, prevent such rotation by design.

[0033] In the Fig. 3 and Fig. 4 can also be seen that the shut-off piston 9 has a head section 27 on the right side in the drawings, into which the main seal 10 ( Fig. 2) is inserted. A base section 28 adjoins the head section 27 and has a reduced diameter compared to the head section 27. The inner bore of the pressure sleeve 13 has a complementary shape, so that it has a radial shoulder which limits the distance by which the shut-off piston 9 can be inserted into the pressure sleeve 13. The recess 24 for the guide body 25 is located in the base section 28 of the shut-off piston 9.

[0034] A connecting pin 29 is attached to the base section 28. The connecting pin 29 projects through a passage 30 located in the second anchor 23. The passage 30 has opposing flat walls 31, 32, which, when the shut-off piston 9 and the second anchor 23 are connected, interact with the parallel side walls 33, 34 of the connecting pin 29. A pin head 35 is located at the end of the shut-off piston 9 opposite the head section 27, and thus at the end of the connecting pin 29. This pin head engages the edge sections of the passage 30 of the second anchor 23. For this purpose, the passage 30 has a recess 36, which is essentially a radial milling into the material of the second anchor 23. The tenon head 35 is slightly wider than the distance between the side walls 33, 34 of the connecting tenon 29.The pin head 35 thus engages behind the edge areas of the recess 36. To insert the pin head 35 into the recess 36, the pin head 35 is inserted into the . Fig. 4 inserted essentially perpendicular to the drawing plane into the recess 36 until it reaches the Fig. 5. occupies a recognizable position.

[0035] In Fig. Figure 5 shows that the second armature 23 is connected to the shut-off piston 9 with minimal axial play of a few millimeters. This axial play is sufficient to lift the pilot seal 19 from the pilot seal seat 37 by moving the second armature 23, allowing pressure equalization to occur through the pressure relief channel (pilot bore) 18. Further axial movement of the second armature 23 moves the shut-off piston 9 with it. Fig.Figure 2 shows that the axial play of the shut-off piston 9 relative to the second armature 23 is considerably smaller than the axial gap 38 between the two armatures 22, 23 in the closed position of the valve 1. Thus, when current is supplied to the coil 17, the displacement of the second armature 23 towards the first armature 22 initially causes the pilot seal 19 to open and subsequently the main seal 10 to open, by pulling the shut-off piston 9 away from the main seal seat 11.

[0036] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 1 electromagnetic valve 2 main bodies 3 cylindrical section 4 external threads 5 filters 6 injectors 7 Main Channel 8 transverse channel 9 shut-off pistons 10 Main seal 11 Main sealing seat 12 connection channels 13 Pressure sleeve 14 external threads 15 internal threads 16 sealing ring 17 coil 18 Pressure relief channel 19 Pilot seal 20 pestles 21 spring 22 first anchor, core 23 second anchor 24 recesses 25 Guide body, guide element 26 groove, guide element 27 Head section 28 Basic section 29 connecting pins 30 Passage area 31 Wall of the passageway 32 Wall of the passageway 33 Side wall of the connecting pin 34 Side wall of the connecting pin 35 pin head 36 Exclusion 37 Pilot control seal seat 38 gap

Claims

[1] Electromagnetic valve (1), in particular for a gas cylinder for gas-powered motor vehicles, with - a main body (2); - a pressure sleeve (13) closed on one side, which is fastened to the main body (2); - a coil (17) surrounding the pressure sleeve (13); - at least one anchor (22, 23) arranged in the pressure sleeve (13); - and at least one shut-off piston (9) which is axially displaceably received in the pressure sleeve (13) and which has a main seal (10) which can be pressed against a main seal seat (11) of the main body (2); characterized bythat the axially displaceable shut-off piston (9) and the pressure sleeve (13) have interlocking guide elements (25, 26) which engage in one another and guide the shut-off piston (9) in a rotationally fixed manner on the pressure sleeve (13), wherein a first armature (22) is pressed into the pressure sleeve (13) and a second armature (23) is received in the pressure sleeve (13) between the first armature (22) and the shut-off piston (13) in an axially displaceable manner, wherein the second armature (23) and the shut-off piston (9) have interlocking connecting elements which engage in one another and which connect the second armature (23) and the shut-off piston (9) in a rotationally fixed manner, wherein the shut-off piston (9) has a connecting pin (29), the end of which points towards the closed end of the pressure sleeve (17) has an enlarged pin head (35), wherein the second armature (23) has a recess (36) for the pin head (35) and has a passage area (30) for the connecting pin (29),wherein the pin head (35) engages behind edge sections of the passage area (30) in a form-fitting manner and wherein the connecting pin (29) is held in the passage area (30) in a rotationally fixed manner. [2] Electromagnetic valve according to claim 1, characterized by that the guide elements include: - an axial groove (26); - a guide body (25); wherein the groove (26) is arranged in one of the two elements secured against rotation relative to one another, namely the pressure sleeve (13) and the shut-off piston (9), wherein the guide body (25) is arranged on the other of these two elements (14, 9) and projects into the groove (26). [3] Electromagnetic valve according to claim 2, characterized by that the groove (26) is arranged on the pressure sleeve (13) and the shut-off piston (9) has a recess (24) into which the guide body (25) is inserted. [4] Electromagnetic valve according to claim 3, characterized bythat the shut-off piston (9) has a head section (27) and a base section (28), wherein the head section (27) has a larger diameter than the base section (28) and the recess (24) is arranged in the base section (28). [5] Electromagnetic valve according to claim 4, characterized by that the pressure sleeve (13) has a first inner diameter at its open end region for receiving the head section (27) and a second inner diameter at the adjoining middle region for receiving the base section (28), the second inner diameter being smaller than the first. [6] Electromagnetic valve according to one of the preceding claims, characterized by that the connecting elements transmit an axial movement of the second armature (23) to the shut-off piston (9). [7] Electromagnetic valve according to one of the preceding claims, characterized bythat the pressure sleeve (13) is made of austenitic steel, which preferably has a high nickel content. [8] Electromagnetic valve according to one of the preceding claims, characterized by that the pressure sleeve (13) is a one-piece component.

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