Solenoid valve with improved air guidance and method for producing solenoid valve

Abstract

The invention discloses a solenoid valve which is provided with a first attachment part (1), a second attachment part (2) and a third attachment part (3). The solenoid valve comprises: at least one closing part (7; 7a, 7b) for opening and closing the first attachment part (1) and the second attachment part (2); an armature (5) for closing the at least one closing part (7; 7a, 7b), and wherein the armature (5) cylindrically surrounds the at least one closing part (7; 7a, 7b); and a coil (6) for moving the armature (5). The armature (5) has an armature (6) which protrudes axially beyond the at least one closing part (7; 7a, 7b) having a section (5a) with a through opening (13a) and an axially extending side channel (14) for guiding an air flow from the first attachment part (1) to the third attachment part (3).

Description

Technical Field

[0001] The invention relates to a solenoid valve with improved air guidance and a method for producing a solenoid valve, in particular a 3 / 2-way valve with air guidance achieved through bores. Background Art

[0002] For example, solenoid valves are used as 3 / 2-way valves for pressure control of anti-lock brake systems in commercial vehicles or buses or for drive slip control (ASR). These solenoid valves are subject to strong stress during operation and should work reliably after many actuations.

[0003] However, due to the high stresses, conventional solenoid valves can experience significant wear over time, so that reliable switching (opening and / or closing) is no longer possible or is insufficient. In particular, mechanical wear often occurs on the valve seat and / or the closing element due to the sudden switching processes and the high forces that occur therein, especially due to pressure differences. This wear can be further intensified by the air guidance, i.e., by the reversal of the air flow inside the valve. In conventional valves, it has been shown that the components used are often insufficient to withstand the strong air flow permanently.

[0004] Therefore, there is a need for an alternative design for a solenoid valve which, on the one hand, allows simple production and, on the other hand, ensures reliable operation over the entire service life. Summary of the invention

[0005] At least some of the above problems are solved by a solenoid valve according to claim 1 and a production method according to claim 12. The dependent claims define further advantageous embodiments of the subject matter of the independent claim.

[0006] The present invention relates to a solenoid valve having a first attachment, a second attachment and a third attachment. The solenoid valve comprises at least one closing part for opening and closing the first attachment and the second attachment, an armature for moving the at least one closing part and a coil for moving the armature. The armature extends cylindrically around the at least one closing part. The armature has a section protruding axially from the at least one closing part, the section having a through hole and an axially extending side channel (e.g., a groove) to guide the air flow from the first attachment to the third attachment. In this way, the solenoid valve becomes a two-position three-way solenoid valve.

[0007] The through-hole is defined as a passage for the air flow, which has a closed edge in a cross section perpendicular to the air flow. It is therefore not a cutout or a notch, but, for example, a drilled or punched hole. The closing part can be constructed as one part or as a plurality of parts and serves as a sealing element and reliably seals the corresponding valve seat. The sealing element can be designed flat or conically tapered to achieve a good seal. The direction of movement of the armature defines the axial direction.

[0008] Optionally, the solenoid valve comprises a core, in which the first attachment portion is configured as a through opening and forms a valve seat. The armature can then have a (partially) closed end face. Optionally, this end face of the armature can form a cone. The core can optionally form an inner cone on the side facing the armature. This increases the magnet surface. The inner cone of the core and / or the cone of the armature can each be formed by two angled regions.

[0009] By this configuration, the following technical effects can be achieved. First, the guidance of the magnetic field lines changes. The double-conical geometry of the core and the armature causes the magnetic force to tend to decrease when the distance between the armature and the core is small, but the magnetic force increases when the distance between the core and the armature is large. This has a full-face effect on the switching characteristics of the valve, because the valve can be reliably closed without causing excessive force on the core when the closure part hits the valve seat. Therefore, compared with the conventional armature with a slotted armature geometry (i.e., without a through hole), the magnetic force will increase when the distance is large due to the continuous end face of the armature facing the core. Through the closed pole face on the armature, in general, the magnetic force becomes higher, which additionally contributes to the reliable movement of the armature caused by the coil. Therefore, in general, a higher magnetic force can be achieved by affecting the characteristic curve when the distance between the core and the armature is large. It is thus ensured that the movement of the armature can be caused by the coil even when the distance between the core and the armature is large. Therefore, it can be ensured that even when the distance is large, the magnetic force is greater than the spring force of the compression spring between the armature and the core.

[0010] Optionally, at least one closing component includes a first closing component and a second closing component. The first closing component is coupled to the armature and opens or closes the first attachment portion based on the movement of the armature. The second closing component is coupled to the armature and closes or opens the second attachment portion based on the movement of the armature. Then, the solenoid valve can also have at least one damping spring, which is arranged between the first closing component and the second closing component and is configured to buffer the closing of the first attachment portion and / or the second attachment portion.

[0011] The through-opening may be a first through-opening and the armature may optionally have a second through-opening in an axially configured region between the first closure part and the second closure part in order to provide pressure compensation between an inner region of the cylindrical armature and the third attachment portion.

[0012] Optionally, the first through-opening and the second through-opening are holes of identical structure. Identical structure may mean that they can be manufactured with the same tool (such as a drill bit) and therefore have no other differences except for the position. Optionally, a plurality of first through-openings and / or a plurality of second through-openings may also be configured in order to better distribute the air flow.

[0013] Optionally, the first closing part and the second closing part each include a head-shoulder region for closing the corresponding first attachment portion or the second attachment portion. The armature can have a protrusion protruding radially into the interior space and an annular notch with a stop element at the opposite end. The protrusion can be configured to form a stop for the head-shoulder region of the first closing part. The notch can be configured to fix the second closing part in the axial direction by the stop element after the first closing part, the damping spring and the second closing part are inserted.

[0014] Optionally, the stop element is a disk fixed in the notch by an edge forging of the armature. However, the stop element does not have to be a continuous disk. It is sufficient if an axial stop for the second closure part is formed. However, the stop element should not be completely fixed.

[0015] The first closure part can also be identical in structure to the second closure part. This offers the advantage that only one type of closure part needs to be manufactured. After insertion, the two closure parts are only rotated 180° relative to each other. This enables simple and cost-effective manufacturing. Only one damping spring needs to be arranged between the first closure part and the second closure part, which presses the first closure part and the second closure part away from each other.

[0016] The solenoid valve may have a chamber into which the armature can move linearly together with at least one closure member, and the first, second and third attachments provide a connection to the chamber (e.g., via an external attachment member). In a state where the coil is energized, at least one closure member may close the first attachment and establish a fluid connection between the second and third attachments via the chamber. In a state where the coil is not energized, at least one closure member may close the second attachment and establish a fluid connection between the first and third attachments via the chamber.

[0017] Some embodiments also relate to a method for manufacturing a solenoid valve as previously defined, the solenoid valve comprising a first attachment portion, a second attachment portion, a third attachment portion, an armature having a cylindrical inner space, and a coil for moving the armature. The method comprises:

[0018] - providing an armature with a side channel;

[0019] - forming a through hole through the armature; and

[0020] - introducing at least one closure element into the armature,

[0021] Therein, after the bringing-in step, the armature has a section which protrudes axially beyond the at least one closure component, and a through-hole is formed in the protruding section in order to guide an air flow from the first attachment portion to the third attachment portion.

[0022] Optionally, the through hole is a first through hole, and the at least one closure part comprises a first closure part and a second closure part. Then, the method can also include forming a second through hole in the following area of ​​the armature, which area is axially located between the first closure part and the second closure part. The same tool can be used here.

[0023] Of course, all previously described features of the solenoid valve can be formed by further optional method steps. In addition, of course, the order in which the steps are named is not necessarily the order in which the method steps are implemented. These steps can also be implemented in a different order or only a part of the method steps can be implemented.

[0024] The exemplary embodiments of the present invention overcome the problems mentioned at the outset by using a hole which can be formed in (only) one working step and does not affect the stability of the armature. In the case of slots and cutouts, however, burrs may form which must be removed with great effort.

[0025] If multiple closing parts are used, (only) one spring provides the advantage that the impact of the two closing parts on the valve seat is damped. For example, this is possible by closing two attachments on opposite sides, which can be damped by a single compression spring.

[0026] These embodiments further offer the advantage that the double damping significantly increases the service life of the solenoid valve. Less damage occurs, and opening and closing are performed with high precision. The solenoid valve is therefore suitable for applications requiring frequent switching processes, as is the case in ABS solenoid valves.

[0027] Another advantage of these embodiments is that the two closure parts can have the same design and can therefore be manufactured interchangeably. This significantly simplifies manufacturing and reduces manufacturing costs. In addition, cost savings are achieved in this way because fewer parts are required due to the double damping.

[0028] The same also applies to the construction of the through-opening, which can be formed by the same type of bore, since the through-opening in the central region between the two closure parts and the through-opening in the upper end region can be produced with the same tool in the same working step. According to these embodiments, the outer channel along the armature can already be present in the pre-processed material (forged material), which also shortens the manufacturing method and the manufacturing time.

[0029] Embodiments of the present invention may be better understood from the following detailed description of different embodiments and the accompanying drawings, which however should not be understood as limiting the present disclosure to specific implementations, but are merely for explanation and understanding. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A solenoid valve according to one embodiment of the present invention is shown.

[0031] Figure 2 Shows Figure 1 A schematic flow chart of a method for manufacturing a solenoid valve. DETAILED DESCRIPTION

[0032] Figure 1 A solenoid valve with improved damping according to an embodiment of the present invention is shown. The valve shown is a two-position three-way valve, which can selectively connect three attachments to each other by means of two switching positions. To this end, the solenoid valve includes a first attachment 1, a second attachment 2, a third attachment 3, an armature 5, a coil 6, a first closing component and a second closing component 7a, 7b and a damping spring 8. The coil 6 is used to move the armature 5 (by magnetic force). The first closing component 7a is coupled to the armature 5 and opens or closes the first attachment 1 when the armature 5 moves through the coil 6. The second closing component 7b is also coupled to the armature 5 and opens or closes the second attachment 2 when the coil 6 moves the armature 5. The damping spring 8 is arranged between the first closing component 7a and the second closing component 7b. When closing the first attachment 1 and / or when closing the second attachment 2, the damping spring 8 slows down the impact (or impact) on the corresponding valve seat. The damping spring thus improves the damping and protects the closure element 7 a , 7 b or the valve seat on the attachment part 1 , 2 .

[0033] The coil 6 can be installed in the valve body housing 10, for example, and extend cylindrically around the core 4 and the armature 5. For example, the core 4 can be firmly arranged in the coil 6 and the first attachment portion 1 can be provided as a through opening. The armature 5 can be arranged in the axial direction ( Figure 1The armature 5 is provided with a protruding section 5a, which protrudes axially from the first closure part 7a and defines a cylindrical inner area, in which the compression spring 11 is guided and the valve seat 12 of the first attachment part 1 is accommodated. Therefore, another advantage of the protruding section 5a of the armature 5 is that an installation space for the compression spring 11 is obtained between the armature 5 and the core 4. This makes the assembly more compact. In conventional solenoid valves, the compression spring is located on the outside of the armature and therefore requires additional installation space. The long groove in the core 4 between the valve seat and the pole face is also much more laborious in terms of manufacturing technology than the protruding section 5a of the armature 5 as constructed in the embodiment.

[0034] The first and second closure parts 7a, 7b can be moved relative to the armature 5 by pressing the damping spring 8. However, this movement is limited by stops in both directions in the axial direction. For this purpose, the first and second closure parts 7a, 7b each include a narrowing area 17a, 17b forming a shoulder-head area, wherein the head section serves to close the respective first or second opening 1, 2, and the shoulder serves as a stop.

[0035] In addition, the armature 5 includes a projection 5c protruding radially into the interior space, which forms a stop for the shoulder section 17a of the first closure part 7a. The compression spring 11 can also act on this inner projection 5c and press the armature 5 away from the core 4. On the opposite end, an annular notch 5d is formed in the armature 5. The annular notch 5d is formed together with the head-shoulder area 17b of the second closure part 7b so that an exemplary disk 9 can be placed there, which is simply fixed, for example, by means of a forging (stauchung) of the armature 5. Then, the two closure parts 7a, 7b are fixed by an axial stop in the armature 5.

[0036] In the de-energized state of the coil 6, the compression spring 11 presses the armature 5 away from the core 4. As a result, the first closing part 7a opens the first attachment portion 1 because the first closing part 7a is carried by the stop 5c. At the same time, the pre-adjusting force of the compression spring 11 is sufficient to move the armature 5 until the armature 5 closes the opposite second attachment portion 2 through the second closing part 7b. Here, the contact of the second closing part 7b to the second attachment portion 2 is damped by the damping spring 8.

[0037] When the coil 6 is energized and thus generates a magnetic field, the armature 5 is magnetically attracted in the direction of the core 4 against the spring tension of the compression spring 11, specifically until the first closing part 7a closes the first attachment 1. In this case, the stopper transmits the force from the armature 5 to the second closing part 7b via the disk 9, which transmits the force to the first closing part 7a via the damping spring 8. Therefore, the compression force when closing the first attachment 1 is limited to the spring force of the damping spring 8, so that the compression force protects the solenoid valve.

[0038] As a result of this movement, either the second attachment part 2 or the first attachment part 1 is opened or closed. When the second attachment part 2 is open (energized state), there is a fluid connection between the third attachment part 3 and the second attachment part 2. In addition to the second attachment part 2, the third attachment part 3 can also be configured in the bottom section in the valve body 10. Then, no additional measures (Vorkehrung) for air guidance are required between the second and third attachment parts 2, 3.

[0039] Figure 1 Only the switching position with the first attachment part 1 opened is shown. In order to guide the air flow from the first attachment part 1 into the inner space of the valve housing 10, the armature 5 has at least two through-openings 13 and at least one side channel 14 (for example formed as a groove). At least two through-openings 13 connect the inner area of ​​the armature 5 and the side channel 14, and provide a fluid connection between the first attachment part 1 and the third attachment part 3. For example, at least one first through-opening 13a is constructed in the protruding section 5a, and at least one second through-opening 13b is constructed in the area 5b of the armature 5, which is axially located between the first closure part 7a and the second closure part 7b. At least one second through-opening 13b provides pressure compensation between the inner area of ​​the armature 5 and the third attachment part 3. The second through-opening 13b is located at the height of the damping spring 8 on the shaft, and due to the pressure compensation, the wear on the first closure part 7a and the second closure part 7b is reduced.

[0040] According to an embodiment, the armature 5 includes a (partially) closed end face 5e facing the core 4. For example, the end face 5e of the armature 5 forms a cone. Similarly, the core 4 can form an inner cone 4e on the side facing the armature 5. Thereby, the magnet surface is increased. In particular, the inner cone 4e of the core 4 and the cone 5e of the armature 5 can respectively form two angled areas. In this way, the end face of the armature 5 forms an armature surface that is completely or partially closed relative to the pole face of the core 4. Compared with a conventional armature with a slotted pole face, according to an embodiment, the magnetic force is increased by a larger pole face.

[0041] The two pole surfaces can be embodied in particular as double cones or by angled regions (see Figure 1) to produce an additional magnet surface. By means of the two pole surfaces thus formed, the area of ​​the armature 5 is increased relative to the core 4 and thus the magnetic force is additionally increased in the case of a larger air gap, since this geometry has a positive influence on the armature characteristic curve.

[0042] Of course, there can be a plurality of through openings 13 and / or a plurality of side channels in order to distribute the air flow as evenly as possible into the interior space due to the significant pressure conditions. The second attachment 2 and the third attachment 3 can be configured as through openings in the valve body housing 10. In the valve body 10, the core 4 can also optionally be moved axially, wherein the axial movement of the core can be achieved by individual control.

[0043] In the embodiment shown, the second attachment part 2 is closed in the rest state (coil without current).

[0044] Figure 2 A flow chart of a method for manufacturing one of the above-mentioned solenoid valves is schematically shown. The method comprises:

[0045] - providing S110 the armature 5 with the side channel 14;

[0046] - constructing S120 a through hole 13 penetrating the armature 5; and

[0047] - Bring at least one closure element 7; 7a, 7b into the armature S130.

[0048] These steps are implemented such that after the step of bringing into S130 , the armature 5 has a section 5a protruding axially beyond at least one closure part 7 ; 7a , 7b , and a through hole 13 is formed in the protruding section 5a to guide the air flow from the first attachment part 1 to the third attachment part 3 .

[0049] The through hole 13 may be a first through hole 13a, and at least one of the closure parts 7a, 7b may include a first closure part 7a and a second closure part 7b. Optionally, the method may further include constructing S135 a second through hole 13b in the region 5b of the armature 5, the region being axially located between the first closure part 7a and the second closure part 7b.

[0050] Optionally, as a further method step, the method comprises constructing S135 a stop for the second closure part 7b to ensure that the first closure part 7a, the second closure part 7b and the damping spring 8 arranged between the first closure part and the second closure part are fixed in the cylindrical cavity of the armature 5. The construction of the stop can, for example, include the insertion of the disk 9 and the edge forging of the armature 5. Afterwards, the disk 9 can no longer be removed from the recess without being destroyed.

[0051] Of course, all other features of the solenoid valve described above can be implemented as further optional method steps in the manufacture. Of course, in addition, the order of naming is not necessarily the order in which the method steps are implemented. These steps can also be implemented in a different order or only a part of these method steps can be implemented.

[0052] Assembly and media booting can be summarized as follows:

[0053] Therefore, the assembly sequence can be carried out as follows: First, a cylindrical armature 5 is provided, into which the first closure part 7a is inserted. The first closure part 7a comprises a head region and a shoulder region, wherein a radially inwardly protruding projection 5c of the armature 5 acts on the shoulder region and provides an impact stop (Anstoβ), so that the first closure part 7a can only move until the radial projection. Then, the damping spring 8 can be inserted into the cylindrical armature 5. Then, the second closure part 7b is placed against the damping spring 8. Finally, the disk 9 is inserted. Since the second closure part 7b also has a shoulder section and a head section, the disk hits the shoulder region and thus provides a stop for the second closure part 7b. For this purpose, the armature 5 comprises a circumferential notch 5d, into which the disk 9 can be inserted. After the armature 5 has been forged at the axial end, the disk 9 and therefore also the second closure part 7b can no longer be removed from the interior of the armature 5, because the deformation of this axial end of the armature 5 prevents the removal of the disk 9. Subsequently, the armature can be inserted together with the core 4 into the interior of the valve housing 10, and after the core 9 has been fixed, the solenoid valve is ready for use.

[0054] The air movement in the individual switching positions takes place along the through openings 13 and the outer channels 14. For this purpose, one or more channels 14 are provided along the cylindrical outer surface of the armature 5, which allow an axial air flow to enter or leave the third attachment part 3. Thus, the medium guide (air) flows from the first attachment part 1 through the core valve seat 12 to the third attachment part 3 and is guided through the transverse hole 13 in the armature 5. The air guide continues to flow from the transverse hole 13 in the armature 5 to the third attachment part 3 via the outer channels.

[0055] The advantage of this air guide is that the outer channel 14 of the armature 5 can already exist in the pre-processed material (Vormaterial) and does not need to be processed separately. Therefore, this can also be constructed by a turning process before manufacturing the armature 5, for example. This saves process time and thus also saves costs. The transverse hole 13 in the armature 5 enables air guidance from the inside to the outside and from the outside to the inside. In addition, the transverse hole 13 for air guidance between the first attachment part 1 and the third attachment part 3 can be the same structure as the transverse hole 13b for establishing pressure compensation between the first closure part 7a and the second closure part 7b.

[0056] The features of the invention disclosed in the description, the claims and the drawings are essential for the implementation of the invention, both individually and in any combination.

[0057] Reference numerals list

[0058] 1, 2, 3 Attachment

[0059] 4 cores

[0060] 4e (Inner) cone section

[0061] 5 Armature

[0062] 5a, 5b, 5c, 5d, 5e Armature sections

[0063] 6 Coil

[0064] 7, 7a, 7b Closure parts

[0065] 8 Damping spring

[0066] 9 plates

[0067] 10 Shell body

[0068] 11 Compression spring

[0069] 12 Valve seat (core)

[0070] 13, 13a, 13b Through opening

[0071] 14 Side channels and grooves

[0072] 15 Chamber (internal space)

[0073] 17a, 17b Narrowing area (shoulder-head area / segment)

Claims

1. A solenoid valve, comprising a first attachment portion (1), a second attachment portion (2) and a third attachment portion (3), wherein: at least one closing member (7; 7a, 7b) for opening and closing the first attachment portion (1) and the second attachment portion (2); An armature (5) for moving the at least one closure element (7; 7a, 7b), wherein: The armature (5) extends cylindrically around the at least one closure part (7; 7a, 7b); and a coil (6) for moving the armature (5), The armature (5) has a section (5a) with a through opening (13a) and an axially extending side channel (14) so ​​as to guide the air flow from the first attachment part (1) to the third attachment part (3) and protrudes axially from the at least one closure part (7; 7a, 7b).

2. The solenoid valve according to claim 1, further comprising a core (4), wherein the first attachment portion (2) is configured as a through-opening in the core, characterized in that: The armature (5) has a closed end surface (5e) which faces the core (4).

3. The solenoid valve according to claim 2, characterized in that: The end surface (5e) of the armature (5) forms a tapered portion, and the core (4) forms an inner tapered portion (4e) on the side facing the armature (5) so as to increase the magnet surface.

4. The solenoid valve according to claim 3, characterized in that: The inner cone (4e) of the core (4) and the cone (5e) of the armature (5) are respectively formed by two areas forming an angle.

5. The solenoid valve according to any one of the preceding claims, characterized in that The at least one closing component (7a, 7b) comprises a first closing component (7a) and a second closing component (7b), wherein the first closing component (7a) is coupled to the armature (5) and opens or closes the first attachment portion (1) based on the movement of the armature (5), and the second closing component (7b) is coupled to the armature (5) and closes or opens the second attachment portion (2) based on the movement of the armature (5), and the solenoid valve further comprises: At least one damping spring (8) is arranged between the first closing part (7a) and the second closing part (7b) and is configured to dampen the closing of the first attachment part (1) and / or the second attachment part (2).

6. The solenoid valve according to claim 5, wherein: The through opening (13a) is a first through opening (13a), characterized in that: The armature (5) has a second through-opening (13b) in an area (5b) axially constructed between the first closure part (7a) and the second closure part (7b) in order to provide pressure compensation between the inner area of ​​the cylindrical armature (5) and the third attachment part (3).

7. The solenoid valve according to claim 6, characterized in that: The first through opening (13a) and the second through opening (13b) are holes with the same structure.

8. The solenoid valve according to any one of claims 5 to 7, characterized in that: The first closing part and the second closing part (7a, 7b) each have a head-shoulder region (17a, 17b) for closing the corresponding first attachment part or second attachment part (1, 2), The armature (5) has a projection (5c) protruding radially into the interior space and has an annular groove (5d) with a stop element (9) at the opposite end, wherein the projection (5c) is designed to form a stop for the head-shoulder area (17a) of the first closure part (7a), and the groove (5d) is designed to fix the second closure part (7b) in the axial direction by means of the stop element (9) after the first closure part (7a), the damping spring (8) and the second closure part (7b) are inserted.

9. The solenoid valve according to claim 8, characterized in that: The stop element (9) is a disk (9) which is fixed in the notch (5d) by means of an edge forging of the armature (5).

10. The solenoid valve according to any one of claims 5 to 9, characterized in that: The first closing component (7a) and the second closing component (7b) have the same structure, and only one damping spring (8) is arranged between the first closing component (7a) and the second closing component (7b), and the damping spring presses the first closing component (7a) and the second closing component (7b) away from each other.

11. The solenoid valve according to any one of the preceding claims, wherein: The solenoid valve has a chamber (15), into which the armature (5) can be linearly moved together with at least one closing part (7; 7a, 7b), and the first, second and third attachment parts (1, 2, 3) provide a connection to the chamber (15), characterized in that When the coil (6) is energized, the at least one closing member (7; 7a, 7b) closes the first attachment portion (1) and establishes a fluid connection between the second attachment portion (2) and the third attachment portion (3) via the chamber (15), and When the coil (6) is not energized, the at least one closing member (7; 7a, 7b) closes the second attachment portion (2) and establishes a fluid connection between the first attachment portion (1) and the third attachment portion (3) via the chamber (15).

12. A method for manufacturing a solenoid valve, wherein: The solenoid valve comprises a first attachment part (1), a second attachment part (2), a third attachment part (3), an armature (5) with a cylindrical inner space, and a coil (6) for moving the armature (5), and the method is characterized in that: Providing (S110) an armature (5) having a side channel (14); constructing (S120) a through hole (13) penetrating the armature (5); and Bringing at least one closure element (7; 7a, 7b) into the armature, In which, after the step of bringing in (S130), the armature (5) has a section (5a) that protrudes axially from the at least one closing part (7; 7a, 7b), and the through opening (13) is constructed in the protruding section (5a) so as to guide the air flow from the first attachment part (1) to the third attachment part (3).

13. The method according to claim 12, wherein: The through hole (13) is a first through hole (13a), and the at least one closing component (7a, 7b) comprises a first closing component (7a) and a second closing component (7b), wherein the method further comprises: A second through hole (13b) is formed (S135) in a region (5b) of the armature (5) which is located axially between the first closure part (7a) and the second closure part (7b).

Images