Housing for a field device and method for attaching an insert in a housing

Abstract

The invention relates to a housing (1) for a field device, comprising: - a housing body (10) which extends along a first axis (A1) and has a housing base (11) and a housing wall (12) surrounding the first axis (A1); - a connecting sleeve (20) which extends along a second axis (A2), oriented in parallel with the first axis (A1), over a sleeve length (21) and is connected to or designed in one piece with the housing base (11) at a first sleeve end (28), wherein the connecting sleeve (20) has a sleeve outer diameter (22) and has, at a second sleeve end (29), a sleeve cavity (23) having a sleeve inner diameter (24); - an insert (30) having a connecting opening (31) which extends in parallel with the second axis (A2) over an opening length (32), wherein the connecting opening (31) has an opening inner diameter (33), wherein the sleeve length (21) is greater than the opening length (32) and the opening inner diameter (33) is greater than the sleeve outer diameter (22), such that the connecting sleeve (20) is suitable for forming, radially to the second axis (A2), a bead (40) having a bead outer diameter (41) greater than the opening inner diameter (33) when the connecting sleeve (20) is arranged in the connecting opening (31) and an expanding tool (50) engages in the sleeve cavity (23) in order to connect the insert (30) to the connecting sleeve (20).

Description

[0001] Housing for a field device and fastening method for a component in a housing

[0002] The invention relates to a housing for a field device and a fastening method for a component in a housing.

[0003] Field device enclosures are used to house electronic measuring and operating circuits. Because these electronic circuits are particularly sensitive and critical components of field devices, the enclosures are subject to especially high demands. Firstly, enclosures should be as small as possible to facilitate easy installation at the point of use. Therefore, the components housed within the enclosure must be arranged in a particularly space-saving manner. Secondly, the enclosures must be suitable for use in potentially explosive atmospheres, necessitating a particularly robust design. Finally, the enclosures should not be too heavy, requiring the use of the lightest possible materials.

[0004] To guarantee the stability of an enclosure, the outer shell is typically made of steel-based materials. Lighter materials are usually used for internal components. A challenge, however, lies in creating a stable and space-saving connection between the different materials of the enclosure's outer shell and the internal components. In particular, welding is usually not possible due to the different materials. Similarly, screw connections should be avoided due to limited space and for reliability reasons. Furthermore, the cost and handling involved in the connection should be kept to a minimum, especially if the connection does not need to be disconnected or disassembled.

[0005] It is therefore an object of the invention to propose a housing for a field device which is stable, space-saving and reliable.

[0006] This problem is solved according to the invention by the housing for a field device according to claim 1.

[0007] The housing according to the invention comprises:

[0008] a housing body which extends along a first axis and has a housing base and a housing wall surrounding the first axis,

[0009] a connecting sleeve which extends along a second axis aligned parallel to the first axis over a sleeve length and is connected to the housing base at a first sleeve end or formed in one piece, wherein the connecting sleeve has a sleeve outer diameter, and at a second sleeve end a sleeve cavity with a sleeve inner diameter,

[0010] a built-in component with a connecting opening which extends parallel to the second axis over an opening length, wherein the connecting opening has an inner opening diameter,

[0011] where the sleeve length is greater than the opening length and the

[0012] The inner diameter of the opening is larger than the outer diameter of the sleeve, so that the connecting sleeve is suitable to form a bead radially to the second axis with a bead outer diameter larger than the inner diameter of the opening when the connecting sleeve is arranged in the connecting opening and a spreading tool engages in the sleeve cavity to connect the component to the connecting sleeve.

[0013] The housing according to the invention enables components arranged inside the housing to be connected to the housing wall in a particularly space-saving and reliable manner. This makes it possible to achieve a connection that is more reliable against vibrations than screw connections. The proposed connection is also more reliable than adhesive connections, particularly against temperature fluctuations and impacts. Compared to rivet connections, the proposed connection also offers advantages in terms of the housing's disassembly, since only a pilot hole, rather than drilling through the connection, is required to detach a component fixed by the connection from the housing shell.

[0014] According to one embodiment of the invention, the installation part has a wing that extends parallel to the second axis and forms a chamber around the connecting sleeve with the housing wall when the installation part is arranged in the connecting opening.

[0015] According to one embodiment of the invention, the connecting sleeve is welded to the housing base and the connecting sleeve is a welded threaded stud with internal thread.

[0016] According to one embodiment of the invention, the internal thread of the welding bolt is less than or equal to M6.

[0017] According to one embodiment of the invention, the connecting sleeve is made of the same material as the housing body.

[0018] According to one embodiment of the invention, an opening distance extends along the second axis in extension to the inner diameter of the opening to the housing wall, and the opening distance is less than 5 mm. According to another embodiment of the invention, the sleeve cavity has a sleeve cavity length extending along the second axis, and the connecting sleeve defines a sleeve projection extending along the second axis and between a sleeve end and a connecting opening end when the connecting sleeve is arranged in the connecting opening, wherein the sleeve cavity length is greater than the sleeve projection.

[0019] According to one embodiment of the invention, the housing body is made of a first material and the installation part is made of a second material different from the first material.

[0020] The above-mentioned problem is also solved by a method for attaching a component in a housing for a field device according to claim 9.

[0021] The method according to the invention comprises:

[0022] Providing a housing according to the invention,

[0023] Arrange the component in the housing body so that the connecting sleeve is positioned in the connecting opening,

[0024] Inserting a spreading tool into the sleeve cavity so that a bead with an outer bead diameter larger than the inner diameter of the connecting opening of the insert is formed and the insert is connected to the connecting sleeve.

[0025] According to one embodiment of the invention, the connecting sleeve is separate from the housing body, wherein, prior to the step of arranging, the connecting sleeve is attached to the housing base with the first sleeve end, and the connecting sleeve is welded to the housing base.

[0026] According to one embodiment of the invention, the spreading tool is sword-shaped, so that the bulge forms essentially along a third axis transverse to the second axis.

[0027] According to one embodiment of the invention, the spreading tool is conical, so that the bead forms essentially symmetrically around the second axis.

[0028] The invention is explained in more detail with reference to the following description of figures. The figures show:

[0029] Fig. 1 : a perspective view of a housing according to the invention,

[0030] Fig. 2: a top view of the housing shown in Figure 1,

[0031] Fig. 3: a sectional view of a connecting sleeve of the housing before connection with the installation part,

[0032] Fig. 4: a sectional view of the connecting sleeve after connection with the

[0033] Installation component, Fig. 5: an exemplary embodiment of a connecting sleeve,

[0034] Fig. 6: a schematic representation of a spreading tool.

[0035] The housing 1 according to the invention for a field device comprises a housing body 10, a connecting sleeve 20 and a mounting part 30, as shown by way of example in Figures 1 and 2.

[0036] Naturally, the use of the housing 1 according to the invention is not limited to field devices, but can also be used in other industries and areas.

[0037] The housing body 10 extends along a first axis A1 and has a housing base 11 and a housing wall 12 that surrounds the first axis A1. The housing body 10 is made of a first material. For example, the housing body 10 is made of steel, preferably stainless steel, or a similarly strong metallic alloy or material. Preferably, the housing body 10 is made of sheet metal, preferably stainless steel sheet metal, by a deep-drawing process. The thickness of the sheet metal is preferably 1.5 mm. Of course, it is also possible to manufacture the housing body 10 by machining processes and / or a casting process.

[0038] The connecting sleeve 20 extends along a second axis A2, which is aligned parallel to the first axis A1, over a sleeve length 21 and has a sleeve outer diameter 22 transverse to the second axis A2. Furthermore, the connecting sleeve 20 has a first sleeve end 28 and a second sleeve end 29 opposite the first sleeve end 28 (see Figure 3). A sleeve cavity 23 is arranged at the second sleeve end 29. The sleeve cavity 23 has a sleeve inner diameter 24 and a sleeve cavity length 25. The sleeve inner diameter 24 extends transversely to the second axis A2. The sleeve cavity length 25 extends parallel to the second axis A2.

[0039] Preferably, the connecting sleeve 20 is suitable for connection to the housing base 11. This is particularly advantageous if the housing body 10 is made of sheet metal. Alternatively, the connecting sleeve 20 is formed integrally with the housing body 10. This embodiment is particularly advantageous if the housing body 10 is manufactured using a machining or casting process.

[0040] When the connecting sleeve 20 is arranged in the connecting opening 31, the connecting sleeve 20 and the insert 30 define a sleeve projection 27 extending along the second axis A2 and between the first sleeve end 28 and a first connecting opening end 35 (see Figure 3). The sleeve cavity length 25 is greater than the sleeve projection 27. This has the advantage that the connecting sleeve 20 can be easily deformed by a spreading tool 50. Preferably, the connecting sleeve 20 has a base 26 at the first sleeve end 28. The base 26 serves, for example, to securely hold the connecting sleeve 20 when welding it to the housing base 11. Furthermore, the connecting sleeve 20 preferably has a centrally arranged pin at the first sleeve end 28 to facilitate a localized initial spark during welding (see Figure 5).

[0041] Preferably, the connecting sleeve 20 is a welding stud, in particular a welded threaded stud according to standard ISO 13918: 2017(E). The welded threaded stud has an internal thread.

[0042] The internal thread is preferably an M4 thread and has a sleeve outer diameter 22 of 6 mm. The sleeve length 21 is preferably 15 mm. The material of the connecting sleeve 20 is preferably carbon steel or stainless steel, in particular A2 steel. Of course, it is also possible to use smaller weld studs with a smaller sleeve outer diameter 22.

[0043] It is also possible to use a sleeve outer diameter of 22 mm with a diameter of 7 mm, preferably using an M6 internal thread, resulting in a thin, deformable wall. The wall thickness is defined by the difference between the sleeve outer diameter 22 mm and the sleeve inner diameter 24 mm.

[0044] If larger outer diameters of 22 are chosen for the sleeves, care must always be taken to ensure that the wall remains sufficiently thin, in particular less than or equal to 2 mm, so that it remains deformable by a spreading tool.

[0045] Preferably, the connecting sleeve 20 is made of the same material as the housing body 10. At a minimum, the connecting sleeve 20 is made of a material that can be welded to the material of the housing body 10.

[0046] The component 30 has a connecting opening 31 that extends parallel to the second axis A2 over an opening length 32. The connecting opening 31 has an inner diameter 33 perpendicular to the second axis A2 (see Figure 3). The connecting opening 31 has a first connecting opening end 35 and a second connecting opening end 36 opposite the first connecting opening end 35 (see Figure 4). The connecting opening 31 is a through hole. The sleeve length 21 of the connecting sleeve 20 is greater than the opening length 32 of the connecting opening 31 of the component 30. The inner diameter 33 of the opening is larger than the outer diameter 22 of the sleeve. The component 30 is made of a second material different from the first material of the housing body 10. The second material cannot, for example, be welded or soldered to the first material. The second material is, for example, aluminum or a plastic.The sleeve length 21 is selected in relation to the opening length 32 such that the connecting sleeve 20 is suitable to form a bead 40 radially to the second axis A2 with a bead outer diameter 41 larger than the opening inner diameter 33 when the connecting sleeve 20 is arranged in the connecting opening 31 and a spreading tool 50 engages in the sleeve cavity 23 to connect the installation part 30 to the connecting sleeve 20.

[0047] Extending along the second axis A2 from the inner diameter 33 of the connecting opening 31 of the insert 30, an opening distance 37 reaches to the housing wall 12 (see Figure 3). The opening distance 37 is thus a lateral distance between the housing wall 12 and the connecting sleeve 20, i.e., a distance available to the connecting sleeve 20 for lateral deformation. The opening distance 37 is preferably less than 5 mm. Due to the small opening distance 37, it is obvious that there is insufficient usable space between the housing wall 12 and the connecting sleeve 20 for inserting tools.

[0048] The spreading tool 50 has a tool diameter 51 that is equal to or larger than the sleeve outer diameter 22. The spreading tool 50 tapers to a point along the second axis A2. For example, the spreading tool 50 is conical at one end (see Figure 6). The cross-sectional area is, for example, round, elliptical, lenticular, or has another shape, such as a star shape. Preferably, the spreading tool 50 is sword-shaped. Sword-shaped is understood to mean a shape that extends essentially straight along the second axis A2 and tapers to a point at one end, with a cross-sectional shape that is lenticular, rhomboid, or triangular. Thus, in the sword-shaped form, the cross-section of the spreading tool 50 extends essentially along a third axis A3, which is arranged transversely to the second axis A2.The advantage of a sword shape is that, when the spreading tool 50 is inserted into the sleeve cavity 23, a deformation of the connecting sleeve 20, i.e., the bead 40, is created. Due to the formation of the bead 40, the connecting sleeve 20 has an outer bead diameter 41, which is larger than the inner opening diameter 33 of the connecting opening 31 of the insert 30. This deformation mechanically connects the insert 30 to the connecting sleeve 20 and thus to the housing body 10.

[0049] As shown in Figure 1, the installation part 30 preferably has at least one wing 34 extending parallel to the first axis A1 and forming a chamber 13 around the connecting sleeve 20 with the housing wall 12 when the installation part 30 is arranged in the connecting opening 31 (see also Figure 2). The wing 34 is preferably made of metal to guarantee a shielding effect for electronic components arranged in the housing body 10. Naturally, the wing 34 does not necessarily have to have a wing shape, but can also take on other arbitrary shapes. In any case, the wing 34 and the housing wall 12 restrict access to the connecting sleeve 20 in such a way that, for example, it is no longer possible to screw it in using a cap nut. In other words, due to the wing 34, access to the connecting sleeve 20 is only possible along the second axis A2.

[0050] Next, the inventive method for fastening the built-in part 30 in the housing 1 for a field device is described.

[0051] The method implicitly includes providing the housing 1 described above. Initially, it is assumed that the connecting sleeve 20 is formed integrally with the housing body 10.

[0052] Then the installation part 30 is arranged in the housing body 10, so that the connecting sleeve 20 is arranged in the connecting opening 31.

[0053] Next, the spreading tool 50 is inserted into the sleeve cavity 23, so that a bead 40 with an outer bead diameter 41 larger than the inner opening diameter 33 is formed, and the component 30 is connected to the connecting sleeve 20. When the spreading tool 50 is inserted, a force F acts on the connecting sleeve 20 such that it deforms. The force F is shown by way of example in Figure 4. The force F is, of course, selected such that the deformation of the connecting sleeve 20 depends on its yield strength and / or material properties.

[0054] The bead 40, for example, refers to a deformation of the connecting sleeve 20 that circumferentially, and in particular concentrically, around the second axis A2. Alternatively, depending on the shape of the spreading tool 50, the bead 40 can be designed such that the connecting sleeve 20 is deformed at least at one point radial to the second axis A2, at two points, or at more points, for example, in a star shape. In any case, a positive fit is formed at least at one point between the connecting sleeve 20 and the installation part 30. In Figure 4, two points that form a positive fit are marked by a black circle.

[0055] In the embodiment in which the connecting sleeve 20 is separate from the housing body 10, the connecting sleeve 20 is attached to the housing base 11 at its first end 28 before the assembly step. Preferably, the connecting sleeve 20 is welded to the housing base 11. For this purpose, the connecting sleeve 20 is held against the base 26 and pressed against the housing base 11.

[0056] The force with which the spreading tool 50 presses on the connecting sleeve 20 is preferably parallel to the second axis A2 and is, of course, dependent on the material chosen for the connecting sleeve 20. The material of the spreading tool 50 has a greater hardness than the material of the connecting sleeve 20. (Reference numeral list)

[0057] 1 case

[0058] 10 Housing bodies

[0059] 11 Case bottom

[0060] 12 Housing wall

[0061] 13th Chamber

[0062] 20 Connecting sleeve

[0063] 21 Sleeve length

[0064] 22 outer diameter of sleeves

[0065] 23 Case cavity

[0066] 24 inner diameter sleeves

[0067] 25 Case cavity length

[0068] 26 sockets

[0069] 27 Case protrusion

[0070] 28 first end of sleeve

[0071] 29 second end of sleeve

[0072] 30 Built-in part

[0073] 31 Connecting opening

[0074] 32 Opening length

[0075] 33 Opening inner diameter

[0076] 34 wings

[0077] 35 first connection opening end

[0078] 36 second connecting opening end

[0079] 37 Opening distance

[0080] 40 bulge

[0081] 41 bead outer diameter

[0082] 50 Spreader tool

[0083] 51 tool diameter

[0084] A1 first axis

[0085] A2 second axis

[0086] A3 third axis

Claims

Patent claims 1. Housing (1) for a field device, comprising: a housing body (10) which extends along a first axis (A1) and has a housing base (11) and a housing wall (12) surrounding the first axis (A1), a connecting sleeve (20) which extends along a second axis (A2) aligned parallel to the first axis (A1) over a sleeve length (21) and is connected to the housing base (11) at a first sleeve end (28) or formed integrally, wherein the connecting sleeve (20) has an outer sleeve diameter (22) and a sleeve cavity (23) with an inner sleeve diameter (24) at a second sleeve end (29), a built-in component (30) with a connecting opening (31) which extends parallel to the second axis (A2) over an opening length (32), wherein the connecting opening (31) has an inner opening diameter (33), wherein the sleeve length (21) is greater than the opening length (32) and the opening inner diameter (33) is greater than the sleeve outer diameter (22), such that the connecting sleeve (20) is suitable to form a bead (40) radially to the second axis (A2) with a bead outer diameter (41) greater than the opening inner diameter (33) when the connecting sleeve (20) is arranged in the connecting opening (31) and a spreading tool (50) engages in the sleeve cavity (23) to connect the insert (30) to the connecting sleeve (20).

2. Housing (1) according to claim 1, wherein the connecting sleeve (20) is welded to the housing base (11) and the connecting sleeve (20) is a weld-on threaded stud with internal thread.

3. Housing (1) according to claim 2, wherein the internal thread of the weld-on threaded stud is less than or equal to M6.

4. Housing (1) according to one of the preceding claims, wherein the connecting sleeve (20) is made of the same material as the housing body (10).

5. Housing (1) according to one of the preceding claims, wherein an opening distance (37) extends along the second axis (A2) in extension to the inner diameter of the opening (33) to the housing wall (12) and the opening distance (37) is less than 5 mm.

6. Housing (1) according to one of the preceding claims, wherein the installation part (30) has a wing (34) which extends parallel to the second axis (A2) and forms a chamber (13) around the connecting sleeve (20) with the housing wall (12) when the installation part (30) is arranged in the connecting opening (31).

7. Housing (1) according to one of the preceding claims, wherein the sleeve cavity (23) has a sleeve cavity length (25) extending along the second axis (A2), and the connecting sleeve (20) defines a sleeve projection (27) extending along the second axis (A2) and between a sleeve end (26) and a connecting opening end (35) when the connecting sleeve (20) is arranged in the connecting opening (31), wherein the sleeve cavity length (25) is greater than the sleeve projection (27).

8. Housing (1) according to one of the preceding claims, wherein the housing body (10) is made of a first material and the installation part (30) is made of a second material different from the first material.

9. Method for fastening a built-in component (30) in a housing (1) for a field device, comprising, Providing a housing (1) according to one of the preceding claims, arranging the installation part (30) in the housing body (10) such that the connecting sleeve (20) is arranged in the connecting opening (31), Inserting a spreading tool (50) into the sleeve cavity (23) so that a bead (40) with an outer bead diameter (41) larger than the inner opening diameter (33) of the connecting opening (31) of the insert (30) is formed and the insert (30) is connected to the connecting sleeve (20).

10. Method according to claim 9, wherein the connecting sleeve (20) is separate from the housing body (10), wherein prior to the arranging step the connecting sleeve (20) is fastened to the housing base (11) with the first sleeve end (28), wherein the connecting sleeve (20) is welded to the housing base (11).

11. Method according to claim 9 or 10, wherein the spreading tool (50) is sword-shaped, such that the bead (40) forms substantially along a third axis (A3) transverse to the second axis (A2).

12. Method according to claim 9 or 10, wherein the spreading tool (50) is conical, such that the bead (40) forms substantially symmetrically about the second axis (A2).

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