Polar tube with metal connection, electromagnet with the polar tube and method for manufacturing the polar tube

Abstract

Pole tube of an electromagnet, in particular for a hydraulic valve, wherein the pole tube forms an armature chamber for receiving an armature of the electromagnet, comprising - a tube section (10) with an inner diameter (d) and an outer diameter (D) at a first end of the polar tube; - a pole piece (20) at a second end of the pole tube (1) that at least partially closes the pipe section (10) - an annular, non-magnetic intermediate piece (30) with an inner diameter between the tube piece (10) and the pole piece (20), which has at least one conical end face (32); and - a metal compound layer (40) on both sides of the annular wall of the non-magnetic intermediate piece (30) both between the tube piece (10) and the non-magnetic intermediate piece (30), as well as between the non-magnetic intermediate piece (30) and the pole piece (20), characterized in that the inner diameter of the non-magnetic intermediate piece (30) is larger than an inner diameter (d) of the tube piece (10).

Description

[0001] The invention relates to a pole tube of an electromagnet, and in particular relates to a pole tube for a hydraulic valve with a tube piece, a pole piece and a non-magnetic intermediate piece between the tube piece and the pole piece, wherein the pole tube forms an armature space for receiving an armature of a magnet.

[0002] Pole tubes of the aforementioned type are components of an electromagnet, which is often used to actuate a hydraulic valve. The pole tube encloses an armature in a pressure-tight manner, which interacts with a plunger or armature rod in a force-locking manner, for example, loosely or rigidly connected to one another, in such a way that the valve can be controlled in an appropriate manner. The pole tube is surrounded by a coil, which carries a plurality of turns of a current-carrying wire, which, when appropriately supplied with electrical current, create a magnetic field to move the armature. The pole piece is specifically shaped for a particular application, as it represents the corresponding interface to the hydraulic valve. The pole tube essentially consists of three elements: a pole piece, a non-magnetic intermediate piece, and a tubular piece.The tube section is terminated at each end by a pole piece and an end section, with the pole piece and end section located at opposite ends of the tube section. The pole tube must be pressure-tight, as the armature chamber is also subjected to the pressure prevailing in the hydraulic circuit of the hydraulic valve. The design of the pole tube itself influences the switching properties and the characteristic curve of the electromagnet.

[0003] For this purpose, it is known to combine materials that guide the magnetic field lines well with non-magnetic materials in the pole tube in order to adjust the characteristic curve appropriately. In particular, the magnetic flux is deflected over a magnetically non-conductive region in such a way that, at a constant current, a force distribution is largely independent of the stroke. In the prior art, the non-magnetic intermediate piece is connected to the tube section on the one hand and to the pole piece on the other hand by means of a welding process, usually a so-called TIG weld or a capacitor discharge weld.

[0004] The pole piece has a through-hole for the passage of the anchor rod, with the inner diameter of the through-hole being smaller than the inner diameter of the anchor chamber. After the individual components have been welded, the inner surface of the resulting blind hole must be machined, primarily by turning. However, surface finishing in a blind hole is difficult to perform, and the quality of this finishing in the blind hole can only be guaranteed and tested with considerable effort, making pole tubes manufactured in this conventional way expensive.

[0005] Furthermore, the welding process previously required to insert the non-magnetic spacer is disadvantageous because, due to the high temperatures involved, fusion welding typically occurs at the joints of the components to be welded. This changes a defined joining edge or joining surface structure and thus counteracts the desired and defined deflection of the magnetic field lines for generating a stroke-independent force distribution. Furthermore, the material can exhibit adverse properties such as hardening or embrittlement after welding and cooling, requiring complex measures or special welding processes to prevent such material changes.

[0006] The generic document DE 44 38 158 A1 discloses an electric lifting magnet with a pole terminating in a cone and a tubular yoke opposite the pole for receiving a substantially cylindrical armature, in which the cone is connected to the yoke by a non-magnetic material.

[0007] The document US 2006 / 0 028 311 A1 discloses an electromagnetic actuating device with an armature which is movable by an electromagnet.

[0008] The invention is therefore based on the object of proposing a pole tube and a method for its production in which the reproducibility of the magnetic field characteristic is achieved with the highest possible quality.

[0009] To achieve this object, the invention proceeds from a pole tube as initially described and proposes that the non-magnetic intermediate piece be joined on both sides to the pole piece on the one hand and to the tube piece on the other by means of a metallic connection, in particular a solder bonding layer or a metal bonding layer. The non-magnetic intermediate piece and its joining surfaces are shaped to achieve a desired or suitable characteristic curve; corresponding joining surfaces are provided on corresponding surfaces of the tube piece and the pole piece, and these surfaces are soldered or bonded in such a way that the shape and structure of the joining surfaces, although pressure-tight and mechanically firmly connected, are retained and do not deform; thus, the previously determined characteristic curve is not altered by the joining process during production.Furthermore, due to the soldering or bonding process, deformation, such as warping or distortion, of the pole tube itself, which can occur due to the high temperatures in the vicinity of joints or joining surfaces that occur during welding processes, is avoided.

[0010] Furthermore, the inventive proposal allows the production of the pole tubes according to the invention in large batch sizes, since the customer-specific adaptation is achieved by the pole piece manufactured according to customer specifications. Furthermore, the machining of the inner surfaces, both of the individual elements and of the entire pole tube, is simpler and can be carried out with better quality than with prior art solutions, which provide a blind bore. The inventive proposal thus combines the advantage of large batch sizes for the production of the pole tube elements with cost-effective or completely eliminated post-processing and / or inspection of the pole tube inner surfaces. This enables cost-efficient mass production with a low scrap rate and thus a significant reduction in manufacturing costs.

[0011] The task is thus solved in detail by - a tube piece having an inner diameter and an outer diameter at a first end of the pole tube; - a pole piece at least partially closing the tube piece at a second end of the pole tube; - an annular, non-magnetic intermediate piece with an inner diameter between the tube piece and the pole piece, which has at least one conical end surface, and - a metal bonding layer on both sides of the annular wall of the non-magnetic spacer, both between the tube piece and the non-magnetic spacer, and between the non-magnetic spacer and the pole piece.

[0012] The inner diameter of the non-magnetic intermediate piece is larger than the inner diameter of the pipe piece.

[0013] The production of the metal connecting layer on both sides of the non-magnetic intermediate piece, that is to say the insertion or joining of the corresponding surfaces of the pole piece and the non-magnetic intermediate piece on the one hand and the non-magnetic intermediate piece and the tube piece on the other hand by, for example, soldering or gluing, makes it possible to keep the characteristic curve predetermined by the design of the non-magnetic intermediate piece or the predetermined course and / or the deflection of the magnetic field characteristics reproducible for a large number of pole tubes, since the geometry, structure and composition of the aforementioned connecting surfaces and the materials used are neither destroyed nor changed by the connecting process.

[0014] In a preferred embodiment, the pole piece has a recess on the intermediate piece side, the inner diameter of which is smaller than, equal to or larger than the inner diameter of the non-magnetic intermediate piece, and the depth of which is greater than the length of a conical section on the circumference of the recess, relative to a direction of an axial center axis.

[0015] With such a recess of a predetermined diameter and a predetermined depth in the pole piece in coordination with the length of the conical section in the axial direction of the pole tube, at which the pole piece and the non-magnetic intermediate piece are joined, it is possible for the armature of the electromagnet to enter and exit a part of the armature space surrounded by a completely magnetizable material on the pole piece side of the non-magnetic intermediate piece, whereby in conjunction with the actual position of the non-magnetic intermediate piece along the axial direction, its actual design and its dimensioning, the tunability of the magnetic field characteristic curve and thus the tunability of the movement and / or switching behavior of the electromagnet is facilitated and improved.

[0016] Furthermore, the depth T is selected so that the wall that defines the recess, i.e. the outer surface and the bottom surface, can be easily machined with cutting tools and subsequently inspected.

[0017] It is particularly advantageous here that the thickness of the annular wall of the non-magnetic intermediate piece is equal to the difference between the outer diameter and the inner diameter of the pipe section and a first width of the inner wall of the non-magnetic intermediate piece is smaller or larger than the width of the outer wall thereof, and the at least one conical end face of the annular wall of the non-magnetic intermediate piece has a larger diameter on the outer side of the annular wall than on the inner side of the annular wall.

[0018] In a preferred embodiment, the at least one conical end face of the annular wall of the non-magnetic intermediate piece is designed to be internally conical or externally conical, and the pole piece has an externally conical or internally conical end face corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece, and at least one end face of the non-magnetic intermediate piece that is orthogonal to an axial direction of a central axis of the non-magnetic intermediate piece is arranged on the tube piece side, and the tube piece has an end face that is aligned with the tube piece-side end face of the non-magnetic intermediate piece and that is orthogonal to the axial direction of the central axis.

[0019] Alternatively, it is equally advantageous to arrange the at least one conical end face of the annular wall of the non-magnetic intermediate piece in an internally conical manner and on the tube piece side, and to provide the tube piece with an end face corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece, and to arrange at least one end wall of the non-magnetic intermediate piece that is orthogonal to an axial direction of a central axis of the non-magnetic intermediate piece on the pole piece side, and to provide the pole piece with an end wall that is aligned with the pole piece-side end wall of the non-magnetic intermediate piece and that is orthogonal to the axial direction of the central axis.

[0020] Depending on the desired characteristic curve, the invention thus enables a suitable design of the non-magnetic intermediate piece without limiting its processability and usability for a pole tube.

[0021] It is also preferred that the at least one conical end face of the annular wall of the non-magnetic intermediate piece is arranged in an internally conical or externally conical manner both on the pole piece side and on the tube piece side, and that both the pole piece and the tube piece have an externally conical or internally conical end face corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece.

[0022] The advantage of this embodiment is an improved self-centering of the non-magnetic intermediate piece during a time of the metal joining process in which the heated joining surfaces are still movable relative to one another or can slide against one another, for example shortly before the intermediate metal joining layer becomes mechanically solid or hardens.

[0023] According to an embodiment not covered by the independent claims, an inner diameter of a recess of the pole piece, the inner diameter of the non-magnetic intermediate piece and the inner diameter of the tube piece are the same, whereby after joining the pole piece, the non-magnetic intermediate piece and the tube piece, a smooth inner surface of the armature space is automatically created, which requires either no or only minor reworking and inspection.In particular, during the manufacture of the pole tube, due to the joining surfaces according to the invention and the dimensioning, for example of the depth of the recess, the axial length of the conical sections, the widths and depths of the elements of the multi-part pole tube in conjunction with the metal joining process and the simultaneous joining, that is to say, connecting mechanically firmly and pressure-tight, by a suitable design of the joining surfaces and / or suitable arrangement and / or rotation of the pole tube during the joining process, it can be prevented that the metal joining material, such as solder or adhesive, for example, flow out of the joining points inwards into the armature space and / or into the recess of the pole piece, so that in this case no post-processing is necessary.

[0024] In a preferred embodiment of the invention, the pole piece has a through-opening axially aligned with a central axis of the tubular piece, the non-magnetic intermediate piece and the pole piece for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and the tubular piece has a stroke limiter for limiting the stroke of the armature rod at an end section opposite the non-magnetic intermediate piece.

[0025] In an alternatively preferred embodiment of the invention, however, it is also possible for the tubular piece to have, on an end side opposite the non-magnetic intermediate piece, an end section with a through-opening axially aligned with a central axis of the tubular piece, the non-magnetic intermediate piece and the pole piece for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and for a recess and / or blind hole to be provided in the pole piece which opens on the intermediate piece side and is closed on the pole piece end side.

[0026] Advantageously, the metal bonding layer pressure-tightly connects both the tube section and the non-magnetic intermediate piece, as well as the non-magnetic intermediate piece and the pole piece, resulting in a pressure-tight pole tube, without the need for additional sealing measures, in a single manufacturing process—i.e., joining the joining surfaces of the pole tube. However, additional seals and / or sealing materials can be used at suitable locations if a need is identified under actual conditions or, for example, if a rapid repair seal is required in the event of a fault.

[0027] In a preferred embodiment of the invention, the pipe section and / or the intermediate piece is / are designed either as an extruded part, a deep-drawn part, or as a cut-to-length pipe section. These parts are therefore obtained in a manufacturing process comprising a deep-drawing, embossing, pressing, or punching operation and can be manufactured cost-effectively. They therefore contribute to reducing manufacturing costs. Of course, it is possible to cut or cut these pieces from corresponding profiled material.

[0028] It should be noted that the metal connection according to the invention can also be easily removed again by reversing the joining process, since only two joining surfaces need to be separated, for example, by appropriate heating, to disassemble the pole tube into its three essential elements. This advantageously opens up replacement options in the event of failure or wear, or provides space and access for modifications.

[0029] Methods that are well suited for the above properties of the invention include a soft soldering method, a brazing method, or a high-temperature soldering method for producing the metal bonding layer formed as a solder bonding layer or an adhesive bonding layer.

[0030] Furthermore, the invention includes both proportional magnets and switching magnets, whereby in particular all advantages apply both to proportional magnets and explicitly to switching magnets.

[0031] Finally, the invention also includes a method for producing a pole tube.

[0032] The method according to the invention is characterized in particular by the fact that the production of a pole tube is characterized by the sequence of the following steps: - preparing a pipe section having an inner diameter and an outer diameter to be arranged at a first end of the pole pipe; - preparing a pole piece to be arranged at a second end of the pole tube, at least partially closing the tube piece; - preparing an annular, non-magnetic intermediate piece with an inner diameter for placement between the tube piece and the pole piece, the annular wall of which has at least one conical end surface; - Connecting both the tube piece and the non-magnetic intermediate piece and the non-magnetic intermediate piece and the pole piece by means of a metal connecting layer on both sides of the annular wall of the non-magnetic intermediate piece.

[0033] The inner diameter of the non-magnetic intermediate piece is larger than the inner diameter of the pipe piece.

[0034] A significant advantage of the method according to the invention is that the tube piece, the non-magnetic intermediate piece and the pole piece are connected to one another simultaneously, preferably in a self-centering manner, in a metal joining process.

[0035] In this context, it is particularly noted that all features and properties described with reference to the pole tube, as well as procedures, are also transferable mutatis mutandis with regard to the formulation of the inventive method and can be used within the meaning of the invention and are deemed to be co-disclosed. The same applies in reverse, so that only structural, i.e., device-related, features mentioned with reference to the method are also considered and claimed within the scope of the claims of the pole tube and thus also count as part of the invention and the disclosure.

[0036] The invention is shown schematically in the drawing. It shows: Fig. 1a , Fig. 1b shows a multi-part pole tube with its essential elements in an unconnected and a connected state according to a first embodiment; Fig. 1c , Fig. 1d shows a multi-part pole tube with its essential elements in an unconnected and a connected state according to a second embodiment; Fig. 2a , Fig. 2b shows a multi-part pole tube with its essential elements in an unconnected and a connected state according to a third embodiment; and Fig. 2c , Fig. 2d a multi-part pole tube with its essential elements in an unconnected and a connected state according to a fourth embodiment.

[0037] In the figures, identical or corresponding elements are designated by the same reference numerals and will therefore not be described again unless appropriate.

[0038] Fig. 1a shows, in a kind of exploded view, schematically the structure of a multi-part pole tube 1 with its three essential elements, in an unconnected state and axially offset from one another with respect to a central axis 2, according to a first embodiment.

[0039] In Fig. 1b is a single, in Fig. Pole tube 1 assembled from the elements shown in Figure 1a is shown.

[0040] According to the invention, the pole tube 1 consists of three assemblies, i.e. a tube section 10 shown on the right-hand side in the figure, a non-magnetic intermediate piece 30 adjoining the tube section 10 on the left-hand side, and a pole piece 20 adjoining the non-magnetic intermediate piece 30 on the left-hand side. In this arrangement of the three assemblies, the non-magnetic intermediate piece 30 is thus located between the pole piece 20 and the tube section 10.

[0041] The pipe section 10 has an inner diameter d, an outer diameter D, and a wall thickness equal to the outer diameter D minus the inner diameter d. In this first exemplary embodiment, a left-hand cross-sectional or end surface 12 of the pipe section 10, which borders the non-magnetic intermediate piece 30, is configured orthogonal to the axial direction of the central axis 2. On the right-hand cross-sectional surface of the pipe section 10 (not further designated), there is an end section which can be suitably shaped as desired, for example, closed off, or which can, for example, lead into a stroke limiter (not shown) for an armature rod or a plunger of the armature. It is noted that the design of the stroke limiter (not shown) is arbitrary and not critical to the invention.

[0042] The pole piece 20 at least partially closes the pole tube 1 at its left opening in the figure.

[0043] As already described, the pole tube 1 serves to create an armature chamber 11 and to guide an armature rod mounted in a through-hole in order to perform a corresponding adjustment process with the movement of the armature outside the pole tube 1. In this context, it is equally important for the purposes of the invention whether there is a rigid connection between the armature rod and the armature or whether they are two separately arranged components. Both variants are encompassed by the invention.

[0044] For supporting and guiding the anchor rod (not shown), the pole piece 20, according to the first exemplary embodiment, has a through-opening 26 in the direction of the central axis 2, which can be designed in the manner of a through-bore and whose inner diameter is smaller than the inner diameter of the anchor space 11, which corresponds to the inner diameter d of the tubular piece 10.

[0045] Furthermore, a preferably, and without being limited to, round-shaped recess 24 with a depth T is provided in the pole piece 20 on its side facing the non-magnetic intermediate piece 30. The depth T is preferably greater than a length L projected onto the axial direction of the central axis 2 of a conical section 22 (see enlargement!), i.e. a conical end face, on the circumference or at the remaining edge of the pole piece 20 in the vicinity of the recess 24. The conical section 22 is in direct connection with at least one conical end face 32 of the non-magnetic intermediate piece 30, which will be described in more detail below.

[0046] Likewise, the depth T of the recess relative to the non-magnetic intermediate piece 30 may be equal to or smaller than an outer width B or equal to or larger than an inner width b of the same.

[0047] The inner diameter of the round or disc-shaped recess 24 is preferably equal to the inner diameter d of the tube section 10, but is not limited thereto. Depending on the desired course of the magnetic field characteristics and the armature stroke of the armature in the armature chamber 11, the inner diameter of the recess 24 can also be larger or smaller than the inner diameter d of the tube section 10.

[0048] The non-magnetic intermediate piece 30 is annular and, according to an embodiment not covered by the independent claims, also has the same inner diameter d as the tube piece 10. Here too, in accordance with the desired course of the magnetic field characteristics and the armature stroke of the armature in the armature space 11, the inner diameter of the non-magnetic intermediate piece 30 can be larger or smaller than the inner diameter d of the tube piece 10. Only the variant with a larger inner diameter of the non-magnetic intermediate piece compared to the pole tube falls under the independent claims.

[0049] In this embodiment, the annular wall of the non-magnetic intermediate piece 30 is designed differently at its end faces and has a conical surface 32 pointing inwards towards the armature space 11 in relation to the pole piece 20, i.e. an inner cone.

[0050] The inner cone 32 corresponds to the aforementioned conical section 22 of the pole piece 20, wherein in this case the conical section 22 of the pole piece 20 forms an outer cone 22 pointing toward the outside of the pole tube 1. The inner cone 32 and the outer cone 22 are preferably designed such that the outer cone 22, on the one hand, forms a seat for the inner cone 32, on which the inner cone 32 can rest in a self-centering manner, and, on the other hand, that smooth transitions are established on the inside of the armature chamber 11 and on the outside of the pole tube 1. In other words, the wall thicknesses of the pole piece 20 and the non-magnetic intermediate piece 30 are preferably the same.

[0051] However, on the side of the non-magnetic intermediate piece 30 facing the pipe section 10, an end face 34 of the same is orthogonal to the direction of the central axis 2 of the pole tube 1, and therefore results in a blunt contact or resting on the corresponding end face 12 of the pipe section 10, which is also orthogonal to the direction of the central axis 2 of the pole tube 1.

[0052] Furthermore, because at least one end face 32 of the non-magnetic intermediate piece 30 is conical, the inner width b of the non-magnetic intermediate piece 30 is smaller than the outer width B thereof.

[0053] Fig. 1b shows the assembled state of the pole tube 1. It is clearly visible that, according to this exemplary embodiment not covered by the independent claims, the tube piece 10, the non-magnetic intermediate piece 30 and the recess 24 of the pole piece 20 have the same inner diameter d of the tube piece 10, so that a continuously smooth and seamless, step-free inner surface of the armature space 11 is obtained, which can be used immediately without any significant or entirely subsequent processing.

[0054] An enlarged section in Fig. 1b shows an exploded view of a metal bonding layer 40 introduced both between pole piece 20 and non-magnetic intermediate piece 30 on the one hand and between non-magnetic intermediate piece 30 and tube piece 10 on the other hand. The enlarged detail is not to scale, since the metal bonding layer 40 is designed to be sufficiently thin or thick to ensure a mechanically strong and simultaneously pressure-tight connection of the surfaces involved.

[0055] Since only two metal connecting layers 40 on the left and right sides of the non-magnetic intermediate piece 30 have to be produced to join the three elements of the pole tube 1, it is easily possible, with a small outer width B or inner width b of the non-magnetic intermediate piece 30, to heat and / or wet the surfaces to be joined closely spaced and thereby to introduce the metal connecting layers 40 in only one joining process for the entire pole tube 1 at the same time, that is to say to produce the pole piece 20, the non-magnetic intermediate piece 30 and the tube piece 10 in a mechanically strong and pressure-tight manner in one operation.

[0056] It should also be noted that this also allows for cost-effective and efficient use of standard components. For example, it is possible to leave pole piece 20 and tube piece 10 unchanged or with only minor modifications for different magnetic field characteristic curves and to process only non-magnetic spacers 30 with different outer widths B and inner widths b, i.e., spacers 30 of different widths.

[0057] The Fig. 1c to Fig. 1d show an embodiment of a multi-part pole tube 1 with its essential elements in an unconnected and a connected state according to a second embodiment.

[0058] In this embodiment, a differently shaped non-magnetic intermediate piece 30 with two internally conical end faces 32 is used, as mentioned above, and therefore not only the right-hand end face 22 of the pole piece 20, but also a left-hand end face 18 of the tube piece 10 is shaped correspondingly externally conically. Of course, the invention is not limited to the Fig. 1b, but alternatively, one or both of the end faces 32 of the non-magnetic intermediate piece 30 can be externally conical, and correspondingly, the end faces of pole piece 20 and tube piece 10 can be internally conical. In individual cases, any possible combination of conical and non-conical end faces 12, 18, 22, 32, 34, optionally also with different cone angles, can be realized. However, only those embodiments in which the intermediate piece has at least one conical end face are covered by the independent claims.

[0059] The Fig. 2a to Fig. 2b show a multi-part pole tube 1 with its essential elements in an unconnected and a connected state according to a third embodiment, and the Fig. 2c to Fig. 2d show a multi-part pole tube 1 with its essential elements in an unconnected and a connected state according to a fourth embodiment.

[0060] The situation in the Fig. 2a to Fig. 2b corresponds to the situation in the Fig. 1a to Fig. 1b, and the situation in the Fig. 2c to Fig. 2d corresponds to the situation in the Fig. 1c to Fig. 1d , where in the Fig. 2a to Fig. 2b, the enlarged sections are not shown repeatedly, and with the exception that the through-opening 26 in the pole piece 20 for the anchor rod (not shown) is omitted, i.e., the pole piece 20 only has the recess 24 and, shaped in this way, completely closes the pole tube 1 on this side, but alternatively, a through-opening 16 for the anchor rod is provided for its support and guidance at an end section 14 of the tube section 10 that at least partially closes the tube section 10. Any desired stroke limitation can then advantageously be connected to the right-hand side of the end section 14, as already described above.

[0061] Also in the examples of the Fig. 2a to Fig. 2d the metal connection is manufactured as in the embodiments of Fig. 1a to Fig.1d by means of a soldering process using a soldering additive or a bonding process using, for example, a suitable adhesive for metals.

[0062] If a soldering process is performed, soft soldering, hard soldering, or high-temperature soldering are preferred. High-temperature soldering (HT soldering) is particularly suitable for joining components made of stainless steel, nickel and cobalt alloys, and ceramics that are subject to high thermal and mechanical stress. This makes it possible to achieve tensile strengths of over 500 N / mm² on stainless steel joints. HT soldering is a flux-free soldering process that takes place at temperatures exceeding 900°C. The soldered joints are primarily produced in closed vacuum furnaces or in protective gas furnaces with a hydrogen or argon atmosphere. Copper, nickel, and cobalt solders are used as solder materials.High-temperature brazing processes also include arc brazing or arc brazing, such as MSG brazing, TIG brazing, or plasma brazing. Due to the low melting temperature of the brazing alloy (between approximately 910 and 1040°C), these brazing processes are characterized by minimal damage to coatings and low thermal stress on the components. This means that the shapes, contours, and structures of the joining surfaces, which are important for adjusting the magnetic field characteristics, change only negligibly or in a reproducible manner. Furthermore, the filler materials used here are largely resistant to corrosion and are therefore suitable for the present application with a fluid-filled armature chamber 11. Furthermore, there is no significant melting of the base material—that is, the materials of the pole piece 20, the non-magnetic intermediate piece 30, and the tube section 10—and fluxes are typically not required.Further advantages are the low distortion of the soldered materials, the low energy consumption and the low solder consumption.

[0063] The metal connections that can be produced using such soldering processes are therefore well suited for the joining surfaces of the pole tube 1 described above and are far superior to the disadvantageous known welding processes, particularly in the present case.

Claims

[1] Pole tube of an electromagnet, in particular for a hydraulic valve, wherein the pole tube forms an armature space for receiving an armature of the electromagnet, comprising - a tube piece (10) having an inner diameter (d) and an outer diameter (D) at a first end of the pole tube; - a pole piece (20) at least partially closing the tube piece (10) at a second end of the pole tube (1) - an annular, non-magnetic intermediate piece (30) with an inner diameter between the tube piece (10) and the pole piece (20), which has at least one conical end face (32); and - a metal bonding layer (40) on both sides of the annular wall of the non-magnetic intermediate piece (30) both between the tube piece (10) and the non-magnetic intermediate piece (30), and between the non-magnetic intermediate piece (30) and the pole piece (20), characterized bythat the inner diameter of the non-magnetic intermediate piece (30) is larger than an inner diameter (d) of the pipe piece (10). [2] Pole tube according to claim 1, characterized by that the metal connection layer (40) is a solder connection layer produced by means of a soft soldering process, a hard soldering process or particularly preferably a high-temperature soldering process, or is an adhesive connection layer produced by means of a metal bonding process. [3] Pole tube according to one or both of the preceding claims, characterized by that the pole piece (20) has a recess (24) on the intermediate piece side, the inner diameter of which is smaller, equal to or larger than the inner diameter of the non-magnetic intermediate piece (30), and the depth (T) of which is greater than the length (L) of a conical section (22) on the circumference of the recess, relative to a direction of an axial central axis (2). [4] Pole tube according to claim 3, characterized bythat the inner diameter of the recess (24) is larger than the inner diameter (d) of the pipe section (10). [5] Pole tube according to one or more of the preceding claims, characterized by that the thickness of the annular wall of the non-magnetic intermediate piece (30) is equal to the difference between the outer diameter (D) and the inner diameter (d) of the pipe section, and a width (b) of the inner wall of the non-magnetic intermediate piece is smaller or larger than the width (B) of the outer wall thereof, and the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30) has a larger diameter on the outer side of the annular wall than on the inner side of the annular wall. [6] Pole tube according to one or more of the preceding claims, characterized byin that the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30) is designed to be internally conical or externally conical, and the pole piece (20) has an externally conical or internally conical end face corresponding to the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30), and on the tube piece side, at least one end face (34) of the non-magnetic intermediate piece (30) is arranged that is orthogonal to an axial direction of a central axis (2) of the non-magnetic intermediate piece (30), and the tube piece (10) has an end face (12) that is aligned with the tube piece-side end face (34) of the non-magnetic intermediate piece (30) and that is orthogonal to the axial direction of the central axis (2). [7] Pole tube according to one or more of the preceding claims, characterized bythat the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30) is arranged in an internally conical manner and on the tube piece side, and the tube piece (10) has an externally conical end face corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece (30), and on the pole piece side, at least one end face of the non-magnetic intermediate piece (30) is arranged which is orthogonal to an axial direction of a central axis (2) of the non-magnetic intermediate piece (30), and the pole piece (20) has an end face which is aligned with the pole piece-side end face of the non-magnetic intermediate piece (30) and which is orthogonal to the axial direction of the central axis (2). [8] Pole tube according to one or more of the preceding claims, characterized bythat the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30) is arranged in an internally conical or externally conical manner both on the pole piece side and on the tube piece side, and both the pole piece (20) and the tube piece (10) have an externally conical or internally conical end face corresponding to the at least one conical end face (32) of the annular wall of the non-magnetic intermediate piece (30). [9] Pole tube according to one or more of the preceding claims, characterized by that the pole piece (20) has a through opening (26) axially aligned with a central axis (2) of the tubular piece (10), the non-magnetic intermediate piece (30) and the pole piece (20) for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and the tubular piece (10) has a stroke limiter for limiting the stroke of the armature rod at an end section opposite the non-magnetic intermediate piece (30). [10] Pole tube according to one or more of the preceding claims, characterized by that the tubular piece (10) has, on an end side opposite the non-magnetic intermediate piece (30), an end section (14) with a through opening (16) axially aligned with a central axis (2) of the tubular piece (10), the non-magnetic intermediate piece (30) and the pole piece (20) for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and in the pole piece (20) a recess (24) and / or blind hole is provided which opens on the intermediate piece side and is closed on the pole piece end side. [11] Pole tube according to one or more of the preceding claims, characterized by that the metal connecting layer (40) connects both the tube piece (10) and the non-magnetic intermediate piece (30), as well as the non-magnetic intermediate piece (30) and the pole piece (20) in a pressure-tight manner. [12] Pole tube according to one or more of the preceding claims, characterized by that the tube piece (10), the non-magnetic intermediate piece (30) and the pole piece (20) are self-centering and connected to one another on the same side in a metal joining process. [13] Pole tube according to one or more of the preceding claims, characterized by that the pipe section (10) and / or non-magnetic intermediate piece (30) is / are designed as an extruded part, as a deep-drawn part or as a cut-to-length pipe section. [14] Electromagnet, characterized by a pole tube according to one or more of the preceding claims. [15] Method for producing a pole tube of an electromagnet, in particular for a hydraulic valve, wherein the pole tube forms an armature space for receiving an armature of a magnet, comprising the steps: - preparing a pipe section having an inner diameter and an outer diameter to be arranged at a first end of the pole pipe; - preparing a pole piece to be arranged at a second end of the pole tube, at least partially closing the tube piece; - preparing an annular, non-magnetic intermediate piece with an inner diameter for placement between the tube piece and the pole piece, the annular wall of which has at least one conical end surface; and - connecting both the tube piece and the non-magnetic intermediate piece and the non-magnetic intermediate piece and the pole piece by means of a metal connecting layer on both sides of the annular wall of the non-magnetic intermediate piece, characterized by that the inner diameter of the non-magnetic intermediate piece (30) is larger than an inner diameter (d) of the pipe piece (10). [16] Method according to claim 15, characterized bythat the tube piece, the non-magnetic intermediate piece and the pole piece are joined together simultaneously in a metal joining process. [17] Method according to one or both of the preceding claims 15 and 16, characterized by that the pole piece is provided with a recess on the intermediate piece side, the inner diameter of which is smaller than, equal to or larger than the inner diameter of the non-magnetic intermediate piece and the depth of which is greater than the length of a conical section on the circumference of the recess, relative to a direction of an axial center axis. [18] Method according to claim 17, characterized by that the inner diameter of the recess is larger than the inner diameter of the pipe section. [19] Method according to one or more of the preceding claims 15 to 18, characterized bythat the thickness of the annular wall of the non-magnetic intermediate piece is equal to the difference between the outer diameter and the inner diameter of the pipe section and a width of the inner wall of the non-magnetic intermediate piece is smaller, equal to or greater than the width of the outer wall thereof, and the at least one conical end face of the annular wall of the non-magnetic intermediate piece is produced on the outer side of the annular wall with a larger diameter than on the inner side of the annular wall. [20] Method according to one or more of the preceding claims 15 to 19, characterized bythat the at least one conical end face of the annular wall of the non-magnetic intermediate piece is arranged in an internally conical or externally conical manner on the pole piece side, and the pole piece is produced with an end face that is externally conical or internally conical corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece, and on the tube piece side, at least one end face of the non-magnetic intermediate piece that is orthogonal to an axial direction of a central axis of the non-magnetic intermediate piece is arranged, and the tube piece is produced with an end face that is aligned with the tube piece-side end face of the non-magnetic intermediate piece and that is orthogonal to the axial direction of the central axis. [21] Method according to one or more of the preceding claims 15 to 20, characterized bythat the at least one conical end face of the annular wall of the non-magnetic intermediate piece is arranged in an internally conical or externally conical manner on the tube piece side, and the tube piece is produced with an end face that is externally conical or internally conical corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece, and on the pole piece side, at least one end face of the non-magnetic intermediate piece that is orthogonal to an axial direction of a central axis of the non-magnetic intermediate piece is arranged, and the pole piece is produced with an end face that is aligned with the pole piece-side end face of the non-magnetic intermediate piece and that is orthogonal to the axial direction of the central axis. [22] Method according to one or more of the preceding claims 15 to 21, characterized bythat the at least one conical end face of the annular wall of the non-magnetic intermediate piece is arranged in an internally conical or externally conical manner both on the pole piece side and on the tube piece side, and both the pole piece and the tube piece have an externally conical or internally conical end face corresponding to the at least one conical end face of the annular wall of the non-magnetic intermediate piece. [23] Method according to one or more of the preceding claims 15 to 22, characterized by that a through opening axially aligned with a central axis of the tubular piece, the non-magnetic intermediate piece and the pole piece is created in the pole piece for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and the tubular piece is provided with a stroke limiter for limiting the stroke of the armature rod at an end section opposite the non-magnetic intermediate piece. [24] Method according to one or more of the preceding claims 15 to 23, characterized by that the tube piece has, on an end side opposite the non-magnetic intermediate piece, an end section with a through opening axially aligned with a central axis of the tube piece, the non-magnetic intermediate piece and the pole piece for receiving and / or supporting and / or guiding an armature rod of an armature of the electromagnet, and a recess and / or blind hole is created in the pole piece which opens on the intermediate piece side and is closed on the pole piece end side. [25] Method according to one or more of the preceding claims 15 to 24, characterized by that the metal connecting layer connects both the pipe section and the non-magnetic intermediate piece, as well as the non-magnetic intermediate piece and the pole piece in a pressure-tight manner. [26] Method according to one or more of the preceding claims 15 to 25, characterized bythat the metal connection layer is produced by means of a soft soldering process, a hard soldering process or particularly preferably a high-temperature soldering process as a solder connection layer, or is produced by means of a metal bonding process as an adhesive connection layer. [27] Method according to one or more of the preceding claims 15 to 26, characterized by that the tube piece, the non-magnetic intermediate piece and the pole piece are arranged in a self-centering manner.

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