Electronic functional unit

Abstract

The present invention relates to an electronic functional unit, comprising - a housing (10) with a housing base (12) that can be closed by means of a cover plate (14), and - a spiral composite (30) arranged within the housing (10), which at least comprises the following: a threaded bolt (32) fixed in the axial direction thereof at a abutment (28), a nut (34) screwed onto the threaded bolt (32), and a flow guiding element (36) clamped between the abutment (28) and the nut (34) that at least temporarily serves as a flow guide during the operation of the electronic functional unit. The present invention is remarkable in that a cap (40) made of an electrically insulating material that arches over the nut (34) is clamped between a seat at the spiral composite (30) and a cover plate (14) that is oriented perpendicular to the axial direction of the threaded bolt (32) and is reversibly fixed to the housing base (12).

Description

Field of Technology

[0001] The invention relates to an electronic functional unit, comprising

[0002] - a housing with a housing base that can be closed by means of a cover plate, and

[0003] - a spiral assembly arranged in the housing, which at least comprises the following

[0004] · a threaded bolt fixed in the axial direction thereof at an abutment,

[0005] · a nut screwed onto the threaded bolt, and

[0006] · a flow guiding element clamped between the abutment and the nut, which at least temporarily serves as a drain during the operation of the electronic functional unit. Background Art

[0007] The subsequently published German patent application DE 10 2021 209 864.9 discloses such an electronic functional unit.

[0008] In the mentioned printed document, an electronic drive unit for a motor vehicle is described. A housing divided into two separate vertical sections is disclosed. In the upper vertical section forming an independent electronic device housing with a bottom, side walls and a removable cover plate, the power electronics required for the operation of the electronic machine are arranged. The side walls of the electronic device housing are penetrated by connecting bushings. The cores of the connecting bushings are connected in the interior of the housing to busbars leading to the power electronics. For this purpose, the cores of the bushings transition into angle plates, which are thermally and electrically insulated relative to the bottom of the electronic device housing via so-called heat conducting pads. Using the section of the angle plate supported at the housing bottom, threaded bolts protruding vertically relative to the bottom are pressed and thus axially and rotationally fixed at the angle plates. For electrical contact, busbars with corresponding drill holes can be arranged such that the bolts pass through the drill holes with a small clearance. By means of a nut subsequently screwed onto the bolts, the busbars can be fixed at the angle plates, wherein electrical contact is achieved. As problematic, persistent vibrations have been proven, which the previously known spiral assemblies are subjected to during operation. This can lead to loosening of the nuts. Here, there is less of a risk of failure of the electrical connection that could cause the electronic machine to malfunction. This can be counteracted, for example, by mechanical pre-tensioning of the busbars. As more strongly disadvantageous, the possibility has been observed that the nuts loosen to such an extent that they detach from the threaded bolts and in the most inopportune cases trigger a short circuit in the power electronics. This can lead to subsequent damage to the electronic components, the repair of which is associated with significant costs. Summary of the Invention

[0009] The object of the present invention is to improve such an electronic functional unit in such a way that the detachment of the nut from the threaded bolt is made impossible.

[0010] This object is achieved in that a cap made of electrically insulating material, which arches over the nut, is clamped between a seat at the screw assembly and a cover plate which is oriented perpendicular to the axial direction of the threaded bolt and is preferably reversibly fixed to the housing base.

[0011] According to the invention, a cap made of insulating material, in particular plastic, is flipped onto the nut, wherein the axial height of the cap is measured in such a way that it is clamped with it when the cover plate is placed on. Thereby, despite vibrations, the cap cannot be detached from the threaded bolt under any circumstances, and thus there is no corresponding possibility for the nut either. Even when the nut loosens due to vibrations, it cannot make conductive contact with the components of the electronic functional unit located outside the screw assembly due to its arching over by the cap and trigger a short circuit there.

[0012] The particular location of the mating support of the cap at the screw assembly (i.e., the seat relative to the cover plate) can be designed differently. For example, it can be arranged that the cap is supported on the nut itself. For example, a circumferential collar of the nut can form the seat. This is possible not only in cases where the nut is a conventional hexagon nut, but also in cases where more complex nut types are used, such as cap nuts with a cover and an internal thread molded in the interior of the cover. Such a cap nut can (but does not have to) have a collar-like flange at its open end, at which the cap can be supported. However, the cap nut also offers the possibility that instead of the (possibly completely absent) circumferential collar, the outer wall of the cover itself forms the seat for the cap at the screw assembly. This is the currently preferred form of support of the cap in the context of the present invention.

[0013] Especially in cases where the outer wall portion of the cover tapers towards its closed end, a type of "floating" support of the cap between the cover plate and the cap nut is achieved. The cap can be pushed onto the cover of the cap nut so far that its opening abuts against the outer wall portion of the cover on all sides. Alternatively, spacing-holding elements protruding radially inwards, such as axially extending centering ribs, can be provided at the inner wall of the cap, by means of which the cap is supported at the cover of the cap nut. By the additional axial force exerted on the cap when the cover plate is clamped to the housing base, the preferably slightly elastic material of the electrically insulating cap can be slightly stretched, so that even in the case of relative vibrations of the housing bottom relative to the housing cover plate, it is ensured that the cap abuts permanently not only at the nut but also at the cover plate, thus avoiding any creaking noises and counteracting the loosening of the nut even by the permanent stress.

[0014] The same effect can be achieved when the net cross-section of the cap tapers towards its closed end.

[0015] Independent of its function as a seating for the cap, the choice of cap nut has the important advantage of chip protection. When screwing the nut onto the threaded bolt, the formation of small chips can occur. The reason for this can be burrs left during the manufacture of the nut and / or the threaded bolt, unfortunate simultaneous manufacturing tolerances, or a slightly skewed tightening of the nut. When choosing a cap nut, these chips remain inside the nut's cap and can thus not come into contact with other components of the electronic functional unit and potentially trigger a short circuit.

[0016] In view of the particularly easy assemblability from the cover plate side, it is preferably arranged that the cap of the cap nut has a central pocket notch (Sackausnehmung) with a non-rotationally symmetric inner contour for accommodating a screwdriver tool in its tip region. It is also technically possible to use a cap nut in which the outer wall section of the cap has a non-rotationally symmetric outer contour for accommodating a screwdriver tool.

[0017] As explained, the cap according to the invention serves to reduce the adverse consequences of loosening of the cap. It is even more expediently obvious to immediately minimize the possibility of such loosening. For this, in a particularly preferred refinement of the invention, it is arranged that a clamping disk (Spannscheibe, sometimes also called a tensioning disk) is arranged between the nut and the flow element, in particular fixed to the nut itself, where it is particularly preferably pressed against the nut. Such a clamping disk permanently holds the screw assembly under axial stress, which counteracts the unintentional loosening of the nut.

[0018] However, the clamping disk as an additional element also brings additional problems. Namely, it is conceivable that the clamping disk breaks, which can lead to free fragments inside the electronic functional unit, which in inappropriate cases may cause a short circuit in the electronic device. To counteract this, it is preferably arranged that the cap completely surrounds the outer edge of the clamping disk at its open end. The basic idea explained above, that the cap at the location of the screw assembly holds the loosening elements of the screw assembly and prevents their movement into other areas of the housing, is thus extended to the clamping disk in this refinement. In the case of breakage, its fragments remain trapped inside the cap. It is thus understood by the person skilled in the art that the concept "completely" should not be understood here in the sense of "seamlessly along the entire circumference", but should also include design solutions with the same effect, such as those with retaining fingers distributed along the circumference. Such an embodiment form can be described as a crown-shaped design of the open end of the cap.

[0019] As described at the beginning, it is known from the prior art and is preferably also implemented in the present invention, i.e., the spiral composite is thermally but electrically insulatedly connected to the bottom of the housing via a thermal pad. In practice, however, it has been shown that the thermal pad tends to wrinkle during assembly that is not extremely careful. In order to counteract this and to accelerate and simplify the assembly, in an improved embodiment of the present invention, it is provided that the cover cap has, in the region of its open end, a pressing arm that reaches up to the opposite edge of the abutment, such as an angle plate, against which it is supported relative to the thermal pad that is arranged in a space-filling manner between the abutment and the bottom of the housing base. The cover cap is thus assigned another function.

[0020] This versatility of the cover cap is of course associated with a relatively complex shape. When the cover cap is, however, a plastic part manufactured by an injection molding method as preferably provided, there are not too many limitations for the person skilled in the art in view of the shape complexity of this element.

[0021] Therefore, it is quite conceivable that the cover cap is also assigned additional functions. Thus, for example, it is provided that in the region of the closed end of the cover cap, a cover cap-side centering structure is arranged, which interacts centrically with a cover-side centering structure arranged at or formed by the cover plate. Such centering structures allow for a relatively "uneven" and rapid assembly, the inaccuracies of which are corrected by the then acting mutually interacting centering structures when the cover plate is placed on.

[0022] To implement such mutually centering structures, it can be provided, for example, that the cover cap-side centering structure is configured as a centering notch and the cover-side centering structure is configured as a centering mandrel fixed to the cover plate, which projects into the centering structure. The centering mandrel can in particular be configured in a conical manner. The centering notch can preferably be configured cylindrically or also conically, preferably with an angle that is sharper than that of the centering mandrel.

[0023] To maintain the clamping action even in the case of, for example, a decline in the elasticity of the cover cap material due to material aging and / or temperature changes, special elastic elements can be arranged in the interaction region between the cover cap and the cover plate. This can be achieved, for example, by constructing an elastic bulge (Aufwölbung) that bridges a hollow space at the tip of the cover cap, which abuts against the cover plate under elastic deformation. Such a structure serves as a mechanical spring, which maintains a lasting stress when the cover cap is clamped between the spiral composite and the cover plate. The bulge can be designed, for example, in a bridge-like, cross-like, or bubble-like manner.

[0024] Alternatively, it can be provided that a rigid projection is constructed at the tip of the cover cap, which abuts against the cover plate, where the cover plate elastically deforms in the contact region with the projection or can elastically deform when the cover plate is considered in isolation. Such elastic deformability can be achieved, for example, by a region of the cover plate with a particularly thin wall thickness. Through spring elasticity, the maintenance of the stress is obtained when the cover cap is clamped between the spiral composite and the cover plate.

[0025] Typically, the electrical connection includes more than one conductor (Ader). Usually, therefore, a plurality of the helical composites described are arranged side by side in the housing in a narrow proximity. It is clearly possible that each of these helical composites is provided with its own separate cap according to the invention. However, it is considered more appropriate that in cases where the helical composites are adjacent to each other in the housing and there is another helical composite of the same type, that is, with a cap according to the invention, the caps are connected to each other by rigid tabs. The caps belonging to different helical composites then form an element that can be jointly manipulated and assembled in a single assembly step. Those skilled in the art understand that the concept "same type" should be understood here in the sense of "in principle" or "substantially" the same type and not with respect to complete spatial physical characteristics that are irrelevant to the invention.

[0026] In order to achieve very good positional accuracy already when placing the caps, it is preferably provided that one of the caps has distributed on its inner periphery at least three centering ribs that project radially inward and extend longitudinally along the axial direction of the cap, and the other caps have exactly two centering ribs that project radially inward and extend longitudinally along the axial direction of the cap, which are arranged opposite each other in a common centering rib plane that is perpendicular to the shortest connecting line between the threaded bolts. In this way, a type of fixed loose bearing (Fest-Los-Lager) is achieved, where the cap with three ribs is the fixed bearing and the cap with only two ribs is the loose bearing. Such a configuration is also suitable for ensuring precisely positioned assembly even with significant manufacturing tolerances.

[0027] In the context of the previously explained centering of the caps and the persistent maintenance of spring stress, in the case of caps connected to each other, it is preferably provided that the corresponding structures are arranged on the tabs. This can be achieved in the region of the middle of the tab at or near one of the caps. In this way, a plurality of caps can be centered with only one set of corresponding centering structures. Description of the Drawings

[0028] Further features and advantages of the invention result from the following specific description and the drawings.

[0029] Wherein:

[0030] Figure 1 shows an exploded view of a part of an electronic function according to the invention,

[0031] Figure 2 shows a partial cross-sectional view of a functional unit according to the invention in the end position of assembly,

[0032] Figure 3 shows Figure 2Another partial cross-sectional view of the functional unit,

[0033] Figure 4 showing a cross-sectional view perpendicular to the cross-section Figure 3 showing details,

[0034] Figure 5 showing a variant of the details presented in Figure 4 and

[0035] Figure 6 showing a partially hidden perspective view of the cap of the invention center,

[0036] Figure 7 showing a partially hidden perspective view of the cap of the invention center,

[0037] Figure 8 showing a schematic view of a first embodiment of the interaction area between the cap and the cover plate,

[0038] Figure 9 showing a schematic view of a second embodiment of the interaction area between the cap and the cover plate, and

[0039] Figure 10 showing a schematic view of a third embodiment of the interaction area between the cap and the cover plate.

[0040] The same reference signs in the figures indicate the same or similar elements. Detailed Description

[0041] Figure 1 Showing a cross-sectional view of the housing 10, which serves as an electronic device housing for accommodating a power electronics device (not presented in more detail) of an electric vehicle drive. The housing itself consists of a housing base 12 and a cover plate 14 that closes it and is reversibly fixed to the housing base 12. In the presented embodiment, the housing base 12 includes a bottom 16 and side walls 18 extending perpendicular to it. In other embodiments, the side walls 18 can be at least partially fixedly connected to the cover plate, so that the housing base consists essentially of the bottom there. Such design details, however, do not play a role in the present invention.

[0042] In the presented embodiment, the side walls 18 visible in Figure 1 are provided with wall cutouts 20 into which coupling bushings 22 are inserted. The cable cores, which are not visible in Figure 1 inside the coupling bushings 22, transition into angle plates 24 at their ends that are turned relative to the interior of the housing, and the free ends of the angle plates 24 are supported on the bottom 16 via heat-conducting pads 26. As can be better recognized in the illustration of Figures 2 to 5 , the free ends of the angle plates 24 serve as abutments (Anlage, sometimes also referred to as facilities) 28 for the helical composite 30.

[0043] In the presented embodiment, as can be recognized in Figures 2 to 5 , the helical composite 30 includes the above-mentioned abutment 28 and a threaded bolt 32 extending perpendicular thereto and pressed by it, and a nut 34 screwed onto the threaded bolt 32 and configured as a cap nut. Figure 2 These elements are shown in an exploded view. Figure 3 A sectional view in the assembled end state is shown, in which a current-carrying element 36 configured as a busbar is clamped between the abutment 28 and the cap nut 34. Figure 4 And 5 A sectional view perpendicular to this extending through such a helical composite 30 is shown.

[0044] In the presented embodiment, the cap nut 34 is constructed by a cylindrical cover 341, at the open edge of which a flange 342 projects radially outwards and an internal thread 343 corresponding to the external thread of the threaded bolt 32 is provided inside it. The upper side of the cover 341 is provided with a central pocket recess 344 having an internal hexagon profile for receiving a screwdriver bit (e.g., TORX ® ).

[0045] In the presented embodiment, a clamping disk 38 is additionally provided, which is pressed against the lower edge of the flange 342 in the drawing and is clamped between the cap nut 34, in particular its flange 342, and the busbar 36 in the assembled end state.

[0046] A cover cap 40 made of electrically insulating plastic is put on the cap nut 34. As can be recognized especially in Figure 3 and 6 , the cover cap has centering ribs 401 extending in the axial direction inside it, by means of which the cover cap is supported on the outside of the cover 342 of the cap nut 34. In the embodiment presented in Figure 4 , the lower cover cap edge is thus above the flange 342 of the cap nut 34. In the embodiment of Figure 5 , the lower cover cap edge is extended by a surrounding skirt 402, which extends up to the clamping disk 38 and completely surrounds it.

[0047] In the presented embodiment, two identical types, that is to say substantially identical, helical composites 30 are arranged side by side in close proximity, which are distinguished especially only by the special shape of the angle plates 24. Each of the helical composites 30 is provided with a cover cap 40, where in the presented embodiment the cover caps 40 are connected to each other via a common tab 42. In particular, the two cover caps 40 and the tab 42 are constructed as a single-piece injection molded part of a unitary material. On the tab, in particular via Figure 2 and 3The cap 40 on the left is centered, and a hollow columnar protrusion serving as a spring 44 protrudes. It is supported at the cover plate 14 by its cap 40, as can be well recognized especially in Figures 3 to 5 This can be well recognized. Thereby, the cap 40 is clamped between the cover plate 14 and the screw compound 30, especially its cap nut 34. Due to the strength of the tab 42 strengthened by the additional reinforcing rib 46, the force generated by the clamping also acts on the second cap 40.

[0048] Figure 6 and 7 shows a perspective partially hidden view of the composite part composed of two caps 40 and the tab 42 connecting them. As can be well recognized, in Figure 6 and 7 three symmetrically distributed centering ribs 401 are arranged in the upper cap 40, while only two centering ribs 401 are provided in the lower cap 40 respectively. They are in a common plane, which is perpendicular to the connecting line between the two screw compounds 30. This allows for the accurate centering of the cap 40 onto the screw compound 30 even in the case of large manufacturing tolerances.

[0049] Figures 8 to 10 shows an alternative or supplementary solution for the hollow columnar spring 44. They are also implemented in the Figure 8 embodiment. It is supplemented by a conical centering mandrel 48 at the cover plate 14, which extends into the hollow cylindrical opening of the spring 44.

[0050] In Figure 9 the embodiment, a bridge-shaped bending spring 44' is implemented on the tab 42. The bending spring 44' is elastically supported at the cover plate 14.

[0051] In Figure 10 the embodiment, a rigid, sharp at its free end, mandrel or rib-shaped protrusion 44'' is provided, which is supported relative to the cover plate 14, and the cover plate 14 is elastically yieldably configured at least in the contact area of the protrusion 44'' in this embodiment.

[0052] Naturally, the embodiments discussed in the specific specification and shown in the figures are only illustrative embodiments of the present invention. For those skilled in the art, in view of the present disclosure, a wide range of variation possibilities is given.

[0053] List of reference symbols

[0054] 10 housing

[0055] 12 housing base

[0056] 14 cover plate

[0057] 16 Bottom

[0058] 18 Side Wall

[0059] 20 Wall Notch

[0060] 22 Connecting Bushing

[0061] 24 Angle Plate

[0062] 26 Heat Conductive Pad

[0063] 28 Contact Portion / Free End of 24

[0064] 30 Spiral Composite

[0065] 32 Threaded Bolt

[0066] 34 Nut / Cap Nut

[0067] 341 Cover

[0068] 342 Flange

[0069] 343 Internal Thread

[0070] 344 Pocket Notch

[0071] 36 Flow Guide Element / Bus Bar

[0072] 38 Clamping Disk

[0073] 40 Cover Cap

[0074] 401 Centering Rib

[0075] 402 Skirt

[0076] 42 Tab

[0077] 44 Spring

[0078] 44' Bent Spring

[0079] 44'' Protrusion

[0080] 46 Reinforcing Rib

[0081] 48 Centering Mandrel

[0082] 50 Pressing Arm

Claims

1. An electronic functional unit, comprising - a housing (10) with a housing base (12) that can be closed by means of a cover plate (14), and - a spiral assembly (30) arranged within the housing (10), which at least comprises the following · a threaded bolt (32) fixed at a contact portion (28) along its axial direction, · a nut (34) screwed onto the threaded bolt (32), and · a flow guiding element (36) clamped between the contact portion (28) and the nut (34), which at least temporarily functions as a flow guide during the operation of the electronic functional unit, characterized in that a cap (40) made of an electrically insulating material and arching over the nut (34) is clamped between an arch seat at the spiral assembly (30) and a cover plate (14) fixed at the housing base (12) and oriented perpendicular to the axial direction of the threaded bolt (32).

2. The electronic functional unit according to claim 1, characterized in that, The circumferential collar of the nut forms the arch seat at the spiral assembly.

3. The electronic functional unit according to any one of the preceding claims, characterized in that, The nut (34) is configured as a cap nut with a cover (341) and an internal thread (343) formed inside the cover (341).

4. The electronic functional unit according to claim 3, characterized in that The cover (341) has a central pocket notch (344) with a non-rotationally symmetric internal profile for accommodating a spiral tool in its tip region.

5. The electronic functional unit according to any one of claims 3 to 4, characterized in that, The outer wall portion of the cover (341) has a circular cross-section at least in its axially extending section on the tip side.

6. The electronic functional unit according to any one of claims 3 to 5, characterized in that The outer wall portion of the cover has a non-rotationally symmetric outer profile for accommodating a spiral tool.

7. The electronic functional unit according to any one of claims 3 to 6, characterized in that, The outer wall portion of the cover (341) forms the arch seat at the spiral assembly (30).

8. The electronic functional unit according to any one of claims 3 to 7, characterized in that, The outer wall portion of the cover tapers towards its closed end.

9. The electronic functional unit according to any one of the preceding claims, characterized in that, The net cross-section of the cap (40) decreases towards its closed end.

10. The electronic functional unit according to any one of the preceding claims, characterized in that, A clamping disc (38) is arranged between the nut (34) and the flow guiding element (36).

11. The electronic functional unit according to claim 10, characterized in that, The cap (40) completely surrounds the outer edge of the clamping disc (38) at its open end.

12. The electronic functional unit according to any one of the preceding claims, characterized in that, The cap (40) has pressing arms (50) reaching up to the opposite edge of the contact portion (28) in the region of its open end, by means of which the cap is supported relative to a heat conducting pad (26) arranged in a space-filling manner between the contact portion (28) and the bottom (16) of the housing base (12).

13. The electronic functional unit according to any one of the preceding claims, characterized in that, In the region of the closed end of the cap (40), a cap-side centering structure is arranged, which interacts centrically with a cover plate-side centering structure arranged at or formed by the cover plate (14).

14. The electronic functional unit according to claim 13, characterized in that, The cap-side centering structure is configured as a centering notch and the cover plate-side centering structure is configured as a centering mandrel (48) fixed at the cover plate (14), which extends into the centering notch.

15. The electronic functional unit according to any one of the preceding claims, characterized in that, At the tip of the cap, an elastic bulge (44') bridging a hollow space is formed, which abuts against the cover plate (14) under elastic deformation.

16. The electronic functional unit according to any one of claims 1 to 14, characterized in that, At the tip of the cap, a rigid protrusion (44'') is formed, which abuts against the cover plate (14), wherein the cover plate (14) is elastically deformed in the contact region with the protrusion.

17. The electronic functional unit according to any one of the preceding claims, characterized in that, Adjacent to the helical composite member (30), another helical composite member (30) with another cap (40) of the same type is arranged in the housing (10), wherein the caps (40) are connected to each other by rigid tabs (42).

18. The electronic functional unit according to claim 17, characterized in that, One of the caps (40) has distributed on its inner peripheral edge at least three centering ribs (401) extending radially inward and longitudinally extending in the axial direction of the cap (40), and the other cap (40) has exactly two centering ribs (401) extending radially inward and longitudinally extending in the axial direction of the cap (40), which are arranged opposite to each other in a common centering rib plane that is perpendicular to the shortest connecting line between the threaded bolts (32).

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