Connection assembly, and method for fabricating a connection assembly

Abstract

To provide a permanent and conductive connection unit between copper and aluminum by using a simple tool.SOLUTION: A connection assembly includes: a busbar 1 that is made of a first metallic material and has a hole; and a contact element 2 arranged in the hole of the busbar 1 and made of a second metal material. An outer diameter of a portion of the contact element 2 located backward in an insertion direction is larger than that of a portion of the contact element 2 located at a front in the insertion direction. An inner surface of the hole of the busbar 1 is provided with a recess 5 filled with a material of the contact element 2, so that the contact element 2 is held by the hole of the busbar 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a connection assembly having undercuts and retention features. The present invention also relates to a method for connecting a busbar to a contact element to make such a connection assembly. [Background technology]

[0002] Contact elements such as contact rings or contact pins must have different material properties and therefore consist, for example, of copper and aluminum portions. A known method for connecting two or more material layers utilizes localized cold forming with a special punch and die. The punch forces the material layers into a die cavity, where the pressure exerted by the punch causes the metal to flow sideways.

[0003] This method results in a button-shaped extrusion on the die side of the connection assembly that acts as the locking connection, and a small cylindrical cavity on the punch side. An undercut (also called a back taper) is created that forms the connection between the first and second metal materials. Summary of the Invention [Problem to be solved by the invention]

[0004] However, such methods require complex setups using special punches and dies, and therefore there is a need to create a permanent, conductive connection between copper and aluminum using a simple tool. [Means for solving the problem]

[0005] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The present invention is based on the idea of creating a stable and electrically conductive connection between a cylindrical contact element and a busbar by inserting the cylindrical contact element into a hole in the busbar and locally pressing the wall of the contact element against the wall of the hole in the busbar using a tool. Alternatively, a locking element remaining on the contact may be used. This results in a displacement of the material of the wall of the hole in the busbar into which the material of the cylindrical contact element is pressed, creating an undercut (also referred to as a back taper) that permanently holds the cylindrical contact element in the hole in the busbar.

[0007] The present invention relates to a connection assembly comprising a busbar made of a first metallic material, the busbar having a hole. The connection assembly further comprises a contact element disposed in the hole of the busbar and made of a second metallic material. During fabrication of the connection assembly, the contact element is inserted into the hole of the busbar from one side of the busbar. The outer diameter of the portion of the contact element located rearward in the insertion direction is larger than the outer diameter of the portion of the contact element located forward in the insertion direction. During assembly, this has the advantage that the contact element can exit the hole in the busbar in the direction opposite to the insertion direction but cannot enter further into the hole.

[0008] In addition, the inner surface of the hole in the busbar has recesses filled with the material of the contact element, whereby the contact element is held in the hole in the busbar. An advantage of the present invention is to provide a permanent and electrically conductive connection between copper and aluminum.

[0009] In an example of the connection assembly according to the present invention, the first metallic material comprises aluminum.

[0010] In a further example of the connection assembly according to the present invention, the second metallic material comprises copper.

[0011] In a further example of the connection assembly according to the present invention, the contact element is tubular.

[0012] In a further example of the connection assembly according to the present invention, the contact element comprises a ring pin.

[0013] In a further example of the connection assembly according to the present invention, the plurality of parts constituting the connection assembly are at least partially silver-plated. This has the advantage of ensuring good electrical conduction between the parts of the connection assembly.

[0014] A further aspect of the present invention relates to a method for manufacturing the connection assembly according to the present invention, the method including the step of creating holes in the bus bar, for example by punching or drilling. This has the advantage that the holes have a simple configuration. The method is the step of creating a contact element insertable into the holes of the bus bar, wherein the outer diameter of the portion of the contact element located rearward in the insertion direction is larger than the outer diameter of the portion of the contact element located forward in the insertion direction, the step of inserting the contact element into the bus bar, and the step of inserting a removable instrument having a protrusion into the contact element, the protrusion pressing the wall of the contact element against the inner surface of the hole of the bus bar so that the wall of the contact element is deformed radially toward the inner surface of the hole of the bus bar, thereby forming a recess in the inner surface of the hole of the bus bar, and the recess being filled with the material of the contact element pressed against the inner surface of the hole of the bus bar. This results in the automatic formation of an undercut. As an alternative to the removable instrument, a locking element remaining in the component, such as a bushing, may be used.

[0015] The walls of the cylindrical contact element and the walls of the holes in the busbar do not necessarily have protrusions at the beginning of the manufacturing process. Instead, the protrusions are formed on the wall of the contact element during the manufacturing process due to the pressure in the radial direction, and thereby exert the radial pressure on the walls of the holes in the busbar, creating corresponding recesses in the walls of the holes in the busbar. The recesses in the walls of the holes in the busbar are made by the expanding material of the contact element that expands in the radial direction, so they are directly filled by the expanding material of the contact element. Thereby, protrusions that protrude in the radial direction and engage with the walls of the holes in the busbar are formed on the wall of the contact element. Since the radial direction is substantially perpendicular to the insertion direction of the contact element into the holes in the busbar, the protrusions on the wall of the contact element form an undercut that holds the contact element in the holes in the busbar.

[0016] Therefore, the advantage of the method according to the present invention is the formation of an automatic undercut that realizes a permanent and conductive connection between copper and aluminum in a simple and inexpensive manner.

[0017] In an example of the method according to the present invention, the holes in the busbar are made by punching. This has the advantage that the production of the holes is particularly simple and inexpensive.

[0018] In a further example of the method according to the present invention, the holes in the busbar are made by drilling. This has the advantage that the production of the holes is particularly simple and inexpensive.

[0019] In a further example of the method according to the present invention, the holes in the busbar are cylindrical. This has the advantage that the production of the holes is particularly simple and inexpensive due to the simple geometry of the holes in the busbar.

[0020] In a further example of the method according to the present invention, the cylindrical holes in the busbar are particularly straight. This has the advantage that the production of the holes is particularly simple and inexpensive due to the simple geometry of the holes in the busbar.

[0021] In a further example of the method according to the invention, the contact element is tubular. This has the advantage that the contact element can be easily inserted into the hole of the bus bar.

[0022] In a further example of the method according to the invention, the contact element is produced by cold forming. Cold forming represents the plastic forming of a metal below the recrystallization temperature. In the case of aluminum and copper, cold forming, unlike hot forming, does not require heating the material up to the recrystallization temperature. This has the advantage that the production of the contact element is particularly simple and inexpensive.

[0023] For a better understanding of the present invention, the present invention will be described in more detail with respect to the embodiments shown in the following drawings. The same parts are given the same reference numerals and the same component names. Furthermore, some features or combinations of features in the various embodiments illustrated and described may, by themselves, be independent, inventive, or equivalent to the solutions according to the present invention.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0025] Figure 1 shows a schematic cross - sectional view of a connection assembly 7 according to a first exemplary embodiment of the present invention. The connection assembly comprises a busbar 1 made of a first metal material, for example aluminum. The busbar 1 has a hole in which a contact element 2 is disposed. The contact element 2 is made of a second metal material, for example copper, and has a tubular shape. In Figure 1, the contact element 2 is inserted into the bore from below. The outer diameter of the portion of the contact element 2 located rearward in the insertion direction is larger than the outer diameter of the portion of the contact element 2 located forward in the insertion direction. Therefore, the contact element 2 inserted into the hole of the busbar 1 can come out of the hole of the busbar 1, but cannot enter the hole further.

[0026] An instrument 3 is inserted into the tubular contact element 2 in a direction opposite to the insertion direction of the contact element 2. The instrument 3 has a protrusion 4 on its outer surface. This can be, for example, a kind of serrated structure or a difference in diameter. When the instrument 3 is inserted into the tubular contact element 2, the protrusion 4 presses the wall of the contact element 2 against the inner surface 8 of the hole of the busbar 1. Due to this pressure, the wall of the contact element 2 deforms radially towards the inner surface of the hole of the busbar 1. As a result, a recess 5 is formed on the inner surface of the hole of the busbar 1. This recess 5 is filled with the material of the contact element 2 that is pressed against the inner surface of the hole of the busbar 1. As an alternative to the removable instrument 3, a locking element remaining on the component, such as a bushing, may be used.

[0027] Figure 2 shows a cross - section of the connection assembly 7 consisting of the busbar 1, the contact element 2, and the instrument 3 having the protrusion 4. In Figure 2, the instrument 3 is entirely inserted into the tubular contact element 2, a recess 5 is formed on the inner surface 8 of the hole of the busbar 1, and the recess 5 is filled with the material of the contact element 2. The recess 5 filled with the material of the contact element 2 forms an undercut (also referred to as a back - taper) that provides a permanent and electrically conductive connection between the first metal material and the second metal material.

[0028] Figures 3 and 4 illustrate alternative embodiments of the present invention. FIG. 3 shows a schematic cross-sectional view of a connection assembly 70 according to a further exemplary embodiment of the present invention. The connection assembly 70 includes a bus bar 10, a contact element 20, and an appliance 30 having a protrusion 40. In FIG. 3, the appliance 30 is entirely inserted into the tubular contact element 20. The enlarged detailed view in FIG. 3 shows that a recess 50 is formed in the inner surface 80 of the hole of the bus bar 10, and the material of the contact element 20 fills the recess 50. The recess 50 filled with the material of the contact element 20 forms an undercut that provides a permanent and conductive connection between the first metal material and the second metal material.

[0029] In the embodiment shown in FIG. 3, a threaded bushing 6 and a screw as a fitting member 19 are used to create an undercut. The screw 19 includes a male thread 16 that can be screwed into the female thread 15 of the threaded bushing 6. For this purpose, the screw 19 is inserted into the cavity of the appliance 30. The screw 19 has a screw head 13 that is wider than the shank of the screw 19. This prevents the screw 19 from passing through the appliance 30. Accordingly, the threaded bushing 6 is inserted into the cavity of the contact ring 21. The threaded bushing 6 has a widened portion 17 at an end disposed on the opposite side of the female thread 15. This prevents the threaded bushing 6 from passing through the contact ring 21.

[0030] When screw 19 is screwed into threaded bushing 6, the elements of connection assembly 70 disposed between the wide portion at the screw head 13 and the wide portion 17 at the threaded bushing 6 are both pressed. In particular, as a result, the appliance 30 is pushed into the contact element 20. Thereby, the protrusion 40 in the appliance 30 presses the material of the contact element 20 against the inner surface 80 of the hole of the bus bar 10 in the radial direction, whereby the recess 50 is created in the inner surface 80 of the hole of the bus bar 10, and the recess 50 is filled with the material of the pressed contact element. Thus, the recess 50 filled with the material of the contact element 20 forms an undercut that provides a permanent and conductive connection between the first metal material and the second metal material.

[0031] FIG. 4 shows a schematic cross-sectional view of a connection assembly 700 according to a further exemplary embodiment of the present invention. Similar to the connection assembly 7 shown in FIG. 1, the connection assembly 700 shown in FIG. 4 includes a bus bar 100 made of a first metal material, for example, aluminum. The bus bar 100 has a hole in which the contact element 200 is disposed. The contact element 200 is made of a second metal material, for example, copper. The contact element 200 has a shape of at least partially hollow cylinder. The cylinder has an opening 22 connected to the cavity of the cylinder at the bottom surface, that is, the cylinder is tubular on one side.

[0032] On the side opposite to the tubular side, the cylinder is provided with a pin 12 that enables establishing a conductive connection, such as a plug connection to a further contact element (not shown in FIG. 4).

[0033] In FIG. 4, a part of the contact element 200, namely the connecting element 9, is inserted into the perforation (bore) of the bus bar 100 from above. The contact element 200 has a first outer diameter that is significantly smaller than the inner diameter of the bore of the bus bar 100 so that the contact element 200 can be inserted into the bore of the bus bar 100. The contact element 200 includes a retaining element 11 adjacent to the connecting element 9. The retaining element 11 has a second outer diameter that exceeds the inner diameter of the bore of the bus bar 100 to such an extent that the retaining element 11 cannot be inserted into the bore of the bus bar 100. Thus, the retaining element 11 ensures that the contact element 200 can be inserted into the bore of the bus bar 100 only for a distance corresponding to the length of the connecting element 9. When the entire connecting element 9 is inserted into the bore of the bus bar 100, the contact element 200 can no longer be inserted further into the bore of the bus bar 100, but can only be withdrawn from the bore of the bus bar 100 in the direction opposite to the insertion direction.

[0034] When manufacturing the connection assembly 700, the instrument 300 is inserted into the tubular portion of the contact element 200 in the direction opposite to the insertion direction of the contact element 200. As can be seen in the enlarged detailed view in FIG. 4, the instrument 300 has a protrusion 400 on its outer surface. When the instrument 300 is inserted into the tubular portion of the contact element 200, the protrusion 400 presses the wall of the contact element 200 against the inner surface 800 of the bore of the bus bar 100. Due to this pressure, the wall of the contact element 200 is deformed radially towards the inner surface 800 of the bore of the bus bar 100. As a result, a recess 500 is formed in the inner surface 800 of the bore of the bus bar 100. This recess 500 is filled with the material of the contact element 200 pressed against the inner surface of the bore of the bus bar 100.

[0035] The recess 500 filled with the material of the contact element 200 forms an undercut that provides a permanent and conductive connection between the first metal material and the second metal material. Then, a conductive connection can be established between the bus bar 100 and a further contact element (not shown in FIG. 4) by means of the pin 12 in the contact element 200.

Description of the reference numerals

[0036] 1, 10, 100 busbars 2, 20, 200 contact elements 3, 30, 300 appliances 4, 40, 400 protrusions 5, 50, 500 recesses 6 threaded bushings 7, 70, 700 connection assemblies 8, 80, 800 inner surfaces of the holes in the busbars 9 connection elements 11 retaining elements 12 pins 13 screw heads 14 touch guard caps 15 female threads 16 male threads 17 wide portions 18 touch guard caps 19 fitting members (screws) 21 contact rings 22 openings

Claims

1. A bus bar (1) made of a first metal material and having holes, A contact element (2) disposed in the holes of the bus bar (1) and made of a second metal material, A connection assembly comprising: The bus bar (1) has a first side and a second side opposite to the first side, The holes of the bus bar (1) penetrate the first side and the second side, The outer diameter of the portion of the contact element (2) located rearward in the insertion direction is larger than the outer diameter of the portion of the contact element (2) located forward in the insertion direction, The inner wall surface of the hole of the bus bar (1) has recesses (5) filled with the material of the contact element (2) so that the contact element (2) is held in the hole of the bus bar (1), The recesses (5) are provided on the inner wall surface of the hole away from the first side and the second side of the bus bar, Connection assembly.

2. The first metal material contains aluminum, The connection assembly according to claim 1.

3. The second metal material contains copper, The connection assembly according to claim 2.

4. The contact element (2) is tubular, The connection assembly according to claim 1.

5. The contact element (2) comprises a ring pin, The connection assembly according to claim 1.

6. A plurality of components constituting the connection assembly are at least partially silver-plated, The connection assembly according to claim 1.

7. A method for manufacturing the connection assembly according to any one of claims 1 to 6, the method comprising: A step of making the holes in the bus bar (1) so as to penetrate the first side and the second side of the bus bar (1), A step of making the contact element insertable into the hole of the bus bar (1), wherein the outer diameter of the portion of the contact element (2) located rearward in the insertion direction is larger than the outer diameter of the portion of the contact element (2) located forward in the insertion direction, A step of inserting the contact element (2) into the bus bar (1), Inserting a removable instrument having a protrusion (4) on the outside into the contact element (2), wherein the protrusion (4) presses the wall of the contact element (2) against the inner wall surface of the hole of the bus bar (1) such that the wall of the contact element (2) deforms radially towards the inner wall surface of the hole of the bus bar (1), whereby a recess is formed on the inner wall surface of the hole of the bus bar (1) away from the first side and the second side, and the recess is filled with the material of the contact element (2) pressed against the inner wall surface of the hole of the bus bar (1). A method comprising the above. Claim 8 The hole of the bus bar (1) is made by punching. The method according to claim 7 Claim 9 The hole of the bus bar (1) is made by drilling. The method according to claim 7 Claim 10 The hole of the bus bar (1) is cylindrical. The method according to claim 7 Claim 11 The cylindrical hole of the bus bar (1) is linear. The method according to claim 10 Claim 12 The contact element (2) is tubular. The method according to claim 7 Claim 13 The contact element (2) is made by cold forming. The method according to claim 7

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