Material-saving plug connection for leadframes

Abstract

The invention relates to an arrangement (1) comprising a leadframe (2) made of metal and a carrier (3) made of plastic, wherein the leadframe (2) is connected to the carrier (3) via at least one plug connection (4), wherein the at least one plug connection (4) is formed via a respective fixing element (5) of the leadframe (2), said fixing element engaging in a respective receptacle (6) of the carrier (3) and being formed at least partially in a respective cutout (7) of the leadframe (2) on a side (8) of the leadframe (2) that faces the carrier (3).

Description

[0001] Material-saving plug connection for lead frames

[0002] The present invention relates to an assembly comprising a lead frame and a carrier, as well as a method for producing the assembly. The present invention further relates to an assembly for producing an electrical machine comprising the assembly.

[0003] Arrangements are known from the prior art in which a carrier is connected to several lead frames, and the lead frames are fixed to the carrier. For this purpose, the carrier is arranged below the lead frame. The lead frames are made from punched strips. Punching waste regularly arises during the punching process.

[0004] Furthermore, in the manufacture of electrical machines, it is also known to use such arrangements as transport securing devices for lead frames or as assembly aids for the lead frames on stators of an electrical machine, as well as for fixing the lead frames during subsequent plastic overmolding.

[0005] In prior art solutions, there is a need to reduce the amount of punching waste. The object of the invention is therefore to reduce punching waste.

[0006] This object is achieved by the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0007] According to the invention, an arrangement is presented which comprises a stamped grid made of metal and a carrier made of plastic. The stamped grid is connected to the carrier via at least one plug connection, wherein the at least one plug connection is formed via a respective fixing element of the stamped grid, which engages in a respective receptacle of the carrier and which is formed at least partially in a respective cutout of the stamped grid on a side of the stamped grid facing the carrier.

[0008] The arrangement is preferably designed for use in an electrical machine. However, the advantages described herein can generally be achieved in all applications in which a lead frame is connected to a carrier.

[0009] The assembly comprises a metal stamping grid and a plastic carrier. The stamping grid can be stamped from a stamping strip. The stamping strip preferably has a thickness, a length, and a width. The stamping strip is preferably a sheet metal.

[0010] The stamped grid is preferably a sheet metal that is punched from the stamped strip. The thickness of the sheet metal is preferably several times smaller than the length and / or width of the sheet metal. The stamped grid can have two opposing surfaces and several surfaces surrounding the edge. The side of the stamped grid facing the carrier can be adjacent to a surface facing the carrier.

[0011] The lead frame preferably comprises an electrically conductive material. The lead frame particularly preferably comprises copper.

[0012] The lead frame is connected to the carrier via at least one plug connection. The lead frame can be connected to the carrier via one plug connection or via multiple plug connections. Preferably, the lead frame is connected to the carrier via three plug connections. The at least one plug connection connects the carrier and the lead frame. The at least one plug connection has the advantage that the lead frame can be connected to the carrier particularly easily during assembly.

[0013] Preferably, several plug connections are arranged distributed along the lead frame.

[0014] The at least one plug connection is formed via a respective fixing element of the lead frame, which engages in a respective receptacle of the carrier. The respective receptacles are preferably designed such that the fixing element can be held in the receptacle. The respective receptacles can be adapted to the shape of the fixing element. The respective receptacles are preferably designed such that the fixing element is held at at least two opposite points.

[0015] The respective fixing element can be designed as a retaining pin.

[0016] The plug connection is preferably designed so that the resistance force for inserting the fixing element into the receptacle is lower than the resistance force for pulling the fixing element out of the receptacle.

[0017] The advantage of having at least one plug connection is that the lead frame is securely held to the carrier.

[0018] The fixing element is formed at least partially in a respective cutout of the lead frame on a side of the lead frame facing the carrier.

[0019] The lead frame may have multiple sides. When the lead frame is connected to the carrier, at least one side faces the carrier.

[0020] The respective cutout can be a flat recess in the lead frame. Preferably, material is removed from an area of ​​the lead frame between the two opposing surfaces, leaving a retaining element in the cutout.

[0021] The respective cutout can each have an opening to a side of the lead frame facing the carrier, wherein the respective fixing element is directed towards the opening of the respective cutout.

[0022] The punched grid is preferably arranged curved and / or bent on a surface of the carrier, wherein the punched grid has respective bends along the punched grid. The bends preferably have a bend angle of 10° to 90°. The arrangement serves to connect the punched grid to the carrier and to reduce the overall height of the arrangement. The fact that the fixing element is formed at least partially in a respective cutout of the punched grid on a side of the punched grid facing the carrier has the particular advantage that the width of the punched grid and thus the width of the punched strip can be reduced compared to a punched grid whose fixing element protrudes from the side of the punched grid facing the carrier, and thus possible punching waste can be advantageously reduced.According to the invention, it has further been found that the arrangement has the advantage that CC emissions can be saved during production due to less punching waste.

[0023] In a preferred embodiment of the arrangement, the arrangement comprises a second stamped grid made of metal, wherein the second stamped grid is connected to the carrier via at least one plug connection, wherein the at least one plug connection is formed via a respective fixing element of the second stamped grid, which engages in a respective receptacle of the carrier and which is formed at least partially in a respective cutout of the second stamped grid on a side of the second stamped grid facing the carrier. The second stamped grid is preferably arranged at a distance from the stamped grid.

[0024] Particularly preferably, the arrangement comprises a third stamped grid made of metal, wherein the third stamped grid is connected to the carrier via at least one plug connection, wherein the at least one plug connection is formed via a respective fixing element of the third stamped grid, which engages in a respective receptacle of the carrier and which is formed at least partially in a respective cutout of the third stamped grid on a side of the third stamped grid facing the carrier. Preferably, the third stamped grid is arranged at a distance from the second stamped grid and from the stamped grid.

[0025] In a further preferred embodiment of the arrangement, the respective fixing element of the at least one plug connection is formed entirely within the corresponding cutout of the stamped grid. The advantages of the claimed invention are achieved even if only a portion of the fixing element is formed within the cutout. However, if the fixing element is arranged entirely within the corresponding cutout of the stamped grid, the fixing element does not protrude beyond the underside of the stamped grid at all. Accordingly, this embodiment has the particular advantage of minimizing stamping waste.

[0026] In a further preferred embodiment of the arrangement, the lead frame extends between two lateral edges, wherein, in at least one of the plug-in connections, the corresponding cutout of the lead frame is arranged on one of the two lateral edges of the lead frame and / or, in at least one of the plug-in connections, the corresponding cutout of the lead frame is arranged between the two lateral edges, spaced from the two lateral edges of the lead frame. The "and" case is preferred.

[0027] This design has the advantage that forces from the carrier to the lead frame are distributed via several plug connections.

[0028] Preferably, a plug connection with the corresponding cutout of the punched grid is arranged on each of the two lateral edges of the punched grid, and in the case of at least one further plug connection, the corresponding cutout of the punched grid is arranged at a distance from the two lateral edges of the punched grid between the two lateral edges.

[0029] In a further preferred embodiment of the arrangement, a surface of the respective fixing element of the at least one plug connection is at least partially grooved.

[0030] A grooved surface can describe a surface structure. The surface is preferably provided with parallel grooves, ridges, ribs, and / or ridges.

[0031] Preferably, the respective fixing element has an extension direction, wherein the surface of the respective fixing element is partially grooved vertically to the extension direction of the fixing element. Particularly preferably, the fixing element has a Christmas tree-shaped outline. For this purpose, the base of the fixing element is preferably wider than the end of the fixing element, and the surface has prongs or barbs.

[0032] The fixing element can be clamped in the holder via the surface of the fixing element, so that the force required to insert the fixing element into the holder is less than the force required to remove the fixing element from the holder.

[0033] The advantage of this design is that the fixing element is held particularly reliably in the holder and the connection of the carrier to the lead frame during assembly is particularly simple.

[0034] In a further preferred embodiment of the arrangement, the at least one plug connection is a force-locking connection.

[0035] The respective receptacles for the corresponding fixing elements can have clamping jaws to clamp the fixing elements when inserted.

[0036] The advantage of this design is that the fixing element is held particularly reliably in the holder, but is detachable and the connection of the carrier to the lead frame during assembly is particularly simple.

[0037] In a further preferred embodiment of the arrangement, the carrier has a recess into which the lead frame is inserted, wherein the respective receptacle of the at least one plug connection is formed in the recess.

[0038] This design of the arrangement has the advantage that the overall height of the arrangement can be reduced by arranging the receptacle for the respective fixing element in the recess and by protruding the lead frame into the carrier.

[0039] The carrier preferably has a surface that is directed towards the punched grid.

[0040] The recess can be a groove in the surface of the carrier facing the lead frame. The recess can be a channel in the surface of the carrier facing the lead frame. Alternatively, the recess can be a channel or a guide on the surface of the carrier facing the lead frame. The lead frame can partially protrude into the carrier.

[0041] The recess preferably has two ends, the first end being the beginning of the recess and the second end marking the end of the recess. The receptacle for the at least one plug-in connection can have a material projection in the recess, spaced from the first end and / or spaced from the second end. The distance of the material projection from the first end and / or from the second end is configured such that the fixing element can be clamped into the receptacle between the material projection and the first end and / or the fixing element can be clamped into the receptacle between the material projection and the second end. The material projection can be referred to as a clamping jaw.

[0042] The receptacle for the at least one plug connection can have spaced-apart material projections in the recess, spaced apart from the first end and / or spaced apart from the second end. The spacing of the two material projections from one another is configured such that the fixing element can be clamped between the two material projections. The material projections can be referred to as clamping jaws.

[0043] A further advantage of the design is that the lead frame is guided in the recess and movements transverse to the recess can at least be reduced or prevented.

[0044] As a further aspect of the invention, a method for producing an assembly is presented. The method comprises the steps: a) punching the lead frame from a punched strip, b) forming the lead frame, c) connecting the carrier and the lead frame via the at least one plug connection, wherein the respective fixing element of the lead frame is inserted into the corresponding receptacle of the carrier. The described advantages and features of the assembly are applicable and transferable to the method, and vice versa.

[0045] The method is preferably carried out in the described order. In step a), the punched strip is preferably punched with a punching tool of a punching machine. The punching tool can be a cutting tool, so that the punched grid has the desired outline.

[0046] In step b), the lead frame is deformed. Forming the lead frame may involve bending and buckling individual sections of the lead frame.

[0047] In step c), the carrier is connected to the lead frame via at least one plug connection. For this purpose, the respective fixing element of the lead frame is inserted into the corresponding receptacle of the carrier. Preferably, the lead frame is guided into a recess in the carrier.

[0048] As a further aspect of the invention, an assembly for the production of an electrical machine is presented.

[0049] The described advantages and features of the arrangement and method are applicable and transferable to the assembly, and vice versa. The arrangement used in the assembly is preferably designed like the described arrangement.

[0050] The assembly comprises a stator, a rotor and an arrangement, wherein the arrangement comprises a plurality of stamped grids made of metal and a carrier made of plastic, wherein the stamped grids are each connected to the carrier via at least one plug connection, wherein the at least one plug connection is formed via a respective fixing element of the corresponding stamped grid, which engages in a respective receptacle of the carrier and which is formed at least partially in a respective cutout of the corresponding stamped grid on a side of the corresponding stamped grid facing the carrier. The rotor can rotate about an axis of rotation, wherein the stator can be arranged about the axis of rotation and around the rotor. The assembly is used to produce an electrical machine, wherein the arrangement can be used in particular to secure the stamped grids during transport or to hold the stamped grids during the subsequent overmolding of the stamped grids with plastic.The assembly has the particular advantage that less punching waste is generated when punching the lead frames and a lower overall height of the arrangement can lead to a lower overall height of the assembly.

[0051] Preferably, the assembly is arranged on the front side of the stator. The surface of the assembly's support, on which the lead frames are arranged, faces away from the stator.

[0052] Preferably, the electrical machine is an electric motor, in particular a brushless DC motor with delta connection.

[0053] In a preferred embodiment of the assembly, the lead frames each form an interconnection ring.

[0054] The interconnection rings preferably each have a connection contact for applying a phase and a plurality of connection elements for electrically connecting the respective interconnection ring to areas of the stator.

[0055] In a further preferred embodiment of the assembly, the carrier forms a transport protection and / or an assembly aid.

[0056] The interconnection rings can be guided in the respective recess, and the carrier can be connected to the interconnection rings using the respective plug-in connection, allowing the interconnection rings to remain in their position on the carrier during transport. This can facilitate the installation of the interconnection rings to the stator terminals.

[0057] Additionally or alternatively, the interconnection rings can be overmolded with a plastic and can be securely held in the arrangement by their connection to the carrier during overmolding.

[0058] The prior art is explained in more detail below with reference to Figure 1. The invention is explained in more detail with reference to Figures 2 to 6. Figures 2 to 6 show a particularly preferred embodiment, to which the invention is not limited, however. Figures 2 to 6 and the proportions depicted therein are merely schematic. They show:

[0059] Fig. 1 : a schematic view of a prior art device

[0060] Connection of a lead frame and a carrier, and

[0061] Fig. 2: a schematic view of an arrangement according to the invention, and

[0062] Fig. 3: a schematic side view of a punched grid according to the invention from Fig. 2, and

[0063] Fig. 4: a schematic representation of an assembly according to the invention, and

[0064] Fig. 5: a sectional view of an arrangement of the assembly according to the invention from Fig. 4, and

[0065] Fig. 6: a perspective view of the arrangement of the inventive

[0066] Assembly from Fig. 5.

[0067] Fig. 1 shows a schematic view of a connection known from the prior art between a lead frame 2 and a carrier 3 with three fixing elements 5. The connection has an overall height h1.

[0068] Fig. 2 shows a schematic view of an arrangement 1 according to the invention. Arrangement 1 comprises a punched grid 2 made of metal and a carrier 3 made of plastic, wherein the punched grid 2 is connected to the carrier 3 via three plug connections 4, wherein the plug connections 4 are formed via a respective fixing element 5 of the punched grid 2, which engages in a respective receptacle 6 of the carrier 3, and which is formed completely in a respective cutout 7 of the punched grid 2 on a side 8 of the punched grid 2 facing the carrier 3.

[0069] The lead frame 2 extends between two lateral edges 9.1, 9.2. For one of the plug connections 4, the corresponding cutout 7 of the lead frame 2 is arranged on the lateral edge 9.1 of the lead frame 2. For one of the plug connections 4, the corresponding cutout 7 of the lead frame 2 is arranged on the lateral edge 9.2 of the lead frame 2.

[0070] In one of the plug connections 4, the corresponding cutout 7 of the punched grid 2 is arranged at a distance from the two lateral edges 9.1, 9.2 of the punched grid 2 between the two lateral edges 9.1, 9.2.

[0071] A surface 10 of the respective fixing element 5 of the plug connectors 4 is partially grooved. The respective plug connector 4 is a force-locking connection.

[0072] The carrier 3 has a recess 11 into which the lead frame 2 is inserted. The respective receptacle 6 of the corresponding plug connection 4 is formed in the recess 11.

[0073] The arrangement 1 has a height h2, whereby the height h2 is lower than the height h1 of Fig. 1.

[0074] For producing the arrangement 1, a method comprises the following steps: a) punching the punched grid 2 from a punched strip 12, b) forming the punched grid 2, c) connecting the carrier 3 and the punched grid 2 via the three plug connections 4, wherein the respective fixing element 5 of the punched grid 2 is inserted into the corresponding receptacle 7 of the carrier 3.

[0075] Fig. 3 shows a schematic side view of the punched grid according to the invention from Fig. 2. The punched grid 2 is punched from a punched strip 12. The punched strip 12 is a metal sheet.

[0076] Fig. 4 shows a schematic representation of an assembly 13 according to the invention for the production of an electrical machine. The assembly 13 comprises a stator 18, a rotor 17, and an arrangement 1. The stator 18 and the rotor 17 are arranged around a rotational axis 19. The arrangement 1 is arranged on the end face of the stator 18. Fig. 5 shows a sectional view of an arrangement 1 of an assembly 13 according to the invention for the production of an electrical machine. The arrangement 1 comprises a plurality of punched grids 2.1, 2.2, 2.3 made of metal and a carrier 3 made of plastic, wherein the punched grids 2.1 - 2.3 are each connected to the carrier 3 via three plug connections 4, wherein the plug connections 4 are formed via a respective fixing element 5 of the corresponding punched grid 2.1 - 2.3, which engages in a respective receptacle 6 of the carrier 3, and which is at least partially in a respective cutout 7 of the corresponding punched grid 2.1 - 2.3 is formed on a side 8 of the corresponding lead frame 2.1 - 2.3 facing the carrier 3.

[0077] The respective fixing element 5 of the plug connections 4 is completely formed in the corresponding cutout 7 of the corresponding lead frame 2.1 - 2.3.

[0078] A surface 10 of the respective fixing element 5 of the plug connection 4 is partially grooved.

[0079] The respective plug connection 4 is a force-locking connection. The carrier 3 has a plurality of recesses 11 into which the respective lead frames 2.1 - 2.3 are inserted, and the receptacle 6 of the corresponding plug connection 4 is formed in the respective recess 11.

[0080] The lead frames 2.1 - 2.3 each form a connection ring 14.1 - 14.3. The connection rings 14.1 - 14.3 each have a connection contact 15 for applying a phase and several connection elements 16 for connecting the respective connection ring 14.1 - 14.3 to the stator 18.

[0081] Arrangement 1 provides transport protection and assembly aid in the manufacture of an electrical machine.

[0082] Fig. 5 shows a perspective view of an assembly according to the invention from Fig. 4. The lead frames 2.1 - 2.3 each extend between two lateral edges 9.1, 9.2. In one of the plug connections 4, the corresponding cutout 7 of the respective lead frame 2.1 - 2.3 is arranged on the lateral edge 9.1 of the respective lead frame 2.1 - 2.3.

[0083] In one of the plug connections 4, the corresponding cutout 7 of the respective lead frame 2.1 - 2.3 is arranged on the lateral edge 9.2 of the respective lead frame 2.1 - 2.3.

[0084] In one of the plug connections 4, the corresponding cutout 7 of the punched grid 2 is arranged at a distance from the two lateral edges 9.1, 9.2 of the punched grid 2 between the two lateral edges 9.1, 9.2.

[0085] List of reference symbols

[0086] Arrangement, 2.1 - 2.3 Lead frame

[0087] carrier

[0088] Plug connection

[0089] Fixing element

[0090] Recording

[0091] Excerpt

[0092] Side of the lead frame .1 , 9.2 Edge of the lead frame 0 Surface of the fixing element1 Recess 2 Punching strip 3 Assembly 4.1 , 14.2, 14.3 Connection ring 5 Connection contact 6 Connection element 7 Rotor 8 Stator 9 Rotation axis

Claims

Patent claims 1 . Arrangement (1 ) comprising a punched grid (2) made of metal and a carrier (3) made of plastic, wherein the punched grid (2) is connected to the carrier (3) via at least one plug connection (4), wherein the at least one plug connection (4) is formed via a respective fixing element (5) of the punched grid (2), which engages in a respective receptacle (6) of the carrier (3) and which is formed at least partially in a respective cutout (7) of the punched grid (2) on a side (8) of the punched grid (2) facing the carrier (3).

2. Arrangement (1) according to claim 1, wherein the respective fixing element (5) of the at least one plug connection (4) is formed completely in the corresponding cutout (7) of the lead frame (2).

3. Arrangement (1) according to one of the preceding claims, wherein the punched grid (2) extends between two lateral edges (9.1, 9.2), and wherein in at least one of the plug connections (4) the corresponding cutout (7) of the punched grid (2) is arranged on one of the two lateral edges (9.1, 9.2) of the punched grid (2) and / or in at least one of the plug connections (4) the corresponding cutout (7) of the punched grid (2) is arranged at a distance from the two lateral edges (9.1, 9.2) of the punched grid (2) between the two lateral edges (9.1, 9.2).

4. Arrangement (1) according to one of the preceding claims, wherein a surface (10) of the respective fixing element (5) of the at least one plug connection (4) is at least partially grooved.

5. Arrangement (1) according to one of the preceding claims, wherein the at least one plug connection (4) is a force-locking connection.

6. Arrangement (1 ) according to one of the preceding claims, wherein the carrier (3) has a recess (11 ) into which the lead frame (2) is inserted, and wherein the respective receptacle (6) of the at least one plug connection (4) is formed in the recess (11).

7. Method for producing an arrangement (1) according to one of the preceding claims, comprising the steps of: a) punching the punched grid (2) from a punched strip (12), b) forming the punched grid (2), c) connecting the carrier (3) and the punched grid (2) via the at least one plug connection (4), wherein the respective fixing element (5) of the punched grid (2) is inserted into the corresponding receptacle (6) of the carrier (3).

8. An assembly (13) for producing an electrical machine, the assembly (13) comprising a stator (18), a rotor (17) and an arrangement (1), the arrangement (1) comprising a plurality of stamped grids (2.1, 2.2, 2.3) made of metal and a carrier (3) made of plastic, the stamped grids (2.1 - 2.3) each being connected to the carrier (3) via at least one plug connection (4), the at least one plug connection (4) being formed via a respective fixing element (5) of the corresponding stamped grid (2.1 - 2.3), which engages in a respective receptacle (6) of the carrier (3), and which is formed at least partially in a respective cutout (7) of the corresponding stamped grid (2.1 - 2.3) on a side (8) of the corresponding stamped grid (2.1 - 2.3) facing the carrier (3).

9. Assembly according to claim 8, wherein the lead frames (2.1 - 2.3) each form an interconnection ring (14.1, 14.2, 14.3).

10. Assembly according to claim 8 or 9, wherein the carrier (3) forms a transport protection and / or an assembly aid.

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