Contact element

Abstract

A contact element (11) has a crimping region (13) designed for crimping onto an electrical conductor and a contact region (15) having a through-going recess (27) which is radially delimited on the underside (23) of the contact region (15) by a flange (25), wherein the recess (27) has an internal thread (31).

Description

Technical Field

[0001] The present invention relates to a contact element, a stator assembly having such a contact element, and a method for manufacturing the contact element. Background Technology

[0002] In a three-phase motor with a rotor and a stator, the stator phase windings are connected via three stator connecting conductors, which are electrically connected to a circuit board for the power electronics used to control the motor. In conventional motors, the conductors may be connected to the circuit board via tulip-shaped contacts and silver-plated copper sleeves.

[0003] US 10 965 056 B2 also describes the connection of the electric motor. The interface conductor between the stator and the power electronics described in that document each includes a hollow conductor, a stator connecting piece at a first end connected to the stator winding, and a bus at a second end connected to the junction box. Summary of the Invention

[0004] The proposed objective is to provide an improved method for contacting stator connection conductors.

[0005] This objective is achieved by a contact element having the features of claim 1. Furthermore, a stator assembly having such a contact element and a method for manufacturing the contact element are provided.

[0006] A contact element is proposed having: a crimping region designed for crimping onto an electrical conductor; and a contact region having a through groove radially defined by a flange on the underside of the contact region, wherein the groove has an internal thread.

[0007] This contact element is a press-fit contact element, and its contact area can establish a conductive connection by means of a threaded connection, especially with a contact pin with external threads.

[0008] A crimping region is used for electrical connection with a conductor, and a contact element is secured to the conductor via a crimping connection. The crimping region has a conductor receiving portion, and the end region of the conductor is positioned within the crimping region. By deforming the crimping region, the end region of the conductor is pressed against the crimping region. This creates both a mechanical and electrical connection between the conductor and the contact element. In one embodiment, the crimping region forms a longitudinally extending cavity for the conductor, wherein the longitudinally extending edge regions of the crimping region overlap each other to laterally surround the conductor.

[0009] The contact area is designed to establish an electrical connection with a conductor pin (also referred to as a lead) via a threaded connection. Therefore, the contact area has a through groove with internal threads to receive the externally threaded end of the contact pin. This groove extends into a flange relative to the thickness of the contact area. By rotating, the contact pin is screwed into the groove, thus creating a stable mechanical connection between the internal threads and the external threads of the contact pin. Current is primarily transmitted via the contact surface between the contact pin and the contact area. Additional current transmission via the threads as an electrical connection is arbitrary and is generally not considered when designing the dimensions of the contact pin and contact element for the required current transmission. In one embodiment, the contact area extends longitudinally from the crimping area and is a metal plate area with a rectangular or circular basic shape, in which a flanged groove is formed at the center.

[0010] The contact area has a bottom side and an opposite top side, from which the contact pin is screwed in. The length of the internal thread is extended by a sleeve-shaped flange located on the bottom side. This length is greater than the thickness of the metal plate on the other side of the contact area between the groove and the flange. Advantageously, the internal thread extends along the entire length of the flange. Thus, the threaded connection is more stable compared to the case where the length of the internal thread corresponds only to the thickness of the contact area.

[0011] Advantageously, the drawn portion of the flow-formed metal sheet forms grooves and flanges. Here, the contact area is formed by the metal sheet. During the flow forming process, the grooves and flanges are formed by a rotary cylindrical tool with a tapered tip (so-called a flow forming tool). The heat generated by the rotary flow forming tool causes material displacement in the contact area, so that during the flow forming of the groove, the tip of the flow forming tool pressed against the top side of the metal sheet forms a flange on the bottom side of the contact area, which defines the bottom section of the groove like a sleeve. Other terms for flow forming used to manufacture such flanged grooves are flow drilling, flow punch forming, flow punch drilling, or the Flowdrill process (thermal drilling process). The flange has a truncated conical outer surface and concentrates sufficient material on the bottom side of the contact area to form an internal thread of sufficient length to achieve a stable mechanical connection.

[0012] In one embodiment, a support surface for contacting the contact pin is formed on the top side of the contact area. This support surface is the top side region configured to contact the contact pin. The contact pin rests on the support surface when connected to the contact area. An internal thread is spaced from the support surface in a direction perpendicular to the support surface, so that the internal thread does not reach the top side or the support surface.

[0013] In one embodiment, a spring-like region capable of elastic deformation is provided between the support surface and the internal thread. This spring-like region is an advantageous feature resulting from the formation of the tapered flange. No internal thread is provided at the spring-like region. This deformation of the spring-like region is particularly related to the preload applied to the threaded connection via the internal thread. This prevents the threaded connection from loosening due to temperature changes or vibration.

[0014] In one embodiment, the spring region between the support surface and the internal thread widens radially toward the support surface. The spring region extends from the support surface in a funnel shape to the internal thread, wherein the cross-sectional profile of the funnel can be straight or curved.

[0015] The contact element is advantageously formed as a single piece, particularly from a deformed metal plate. Copper is a suitable material for contact elements due to its excellent electrical properties. The integral contact element and its internal threads are simple and inexpensive to manufacture.

[0016] This contact element is a simple electrical component that can be manufactured and assembled in a simple and inexpensive manner. This results in lower risk and a lower scrap rate. The design is easily expandable and can be adapted to different application areas.

[0017] The stator assembly, as part of the electric motor, includes the aforementioned contact elements. The stator assembly includes a stator having at least one stator connection conductor. A contact element is securely fastened at the end of the stator connection conductor, the contact element being electrically connected to a contact pin, wherein the contact pin has an externally threaded end that engages with the internal thread of the contact element. Each phase is controlled via the stator connection conductor. Through the contact elements, the phases of the stator are connected to the circuit board of power electronics via the stator connection conductor in a cost-effective and robust manner, without the need for soldering or pressing. Therefore, complex and expensive machinery is not required during manufacturing.

[0018] In one embodiment, the contact pin has a bearing surface that radially protrudes from the external thread and abuts against a bearing surface of the crimping area. This contact of the surfaces, acting as an abutment surface, causes current transfer between the contact pin and the contact element.

[0019] Advantageously, the external and internal threads engage with each other, causing a preload force to act on the threaded connection due to the spring region. The elastic deformation of the spring region caused by the threaded connection acts on the screwed-in contact pin via the internal thread, and applies preload to the threaded connection.

[0020] In stator assemblies with the aforementioned contact elements, the components used to connect the stator are low-cost. The contact element is simple and therefore can be manufactured inexpensively. It is advantageously made of copper sheet and has threaded holes formed by hot drilling (i.e., flow forming). No milling or complex assembly is required. The contact pins have external threads at their end regions and are similarly easy to manufacture. Assembly is performed by screwing. High pressing forces, thermal processes (such as welding), and expensive equipment are not required.

[0021] A method for manufacturing a contact element according to the invention, the contact element having a crimping region and a contact region, the method comprising: forming a groove in the contact region by means of flow forming and a flange radially defining the groove on the bottom side of the contact region, and forming an internal thread in the groove. Residual material formed for the groove is transferred to the bottom side of the metal plate region and a tapered flange is formed there, through which the groove extends. Due to the flange, a thread with a length exceeding the thickness of the metal plate can be formed. Another effect of the method is that a spring region is formed as the groove and flange are manufactured, where the groove widens. When the contact pin is screwed in, the spring region pre-tightens the contact region relative to the contact pin through its deformation. This prevents the contact pin from loosening due to temperature changes or vibration. Subsequent potting of the contact element connected to the contact pin further improves stability. Attached Figure Description

[0022] The following description, in conjunction with the accompanying drawings, details some embodiments. In the drawings:

[0023] Figure 1 A three-dimensional partial view of one embodiment of the electric motor is shown.

[0024] Figure 2 An embodiment of the contact element is shown in a three-dimensional side view.

[0025] Figure 3 Shown in sectional view Figure 2 Contact elements,

[0026] Figure 4 A cross-sectional view showing a partial three-dimensional illustration of an electric motor.

[0027] Figure 5 A cross-sectional view of the contact element connected to the contact pin is shown, and

[0028] Figure 6 The illustration shows the formation of grooves and flanges through flow forming. Detailed Implementation

[0029] In the accompanying drawings, identical or functionally equivalent components are given the same reference numerals.

[0030] Figure 1 A three-dimensional partial view of an electric motor is shown, which has a stator 1 located within a housing 3. The stator 1 includes three-phase stator windings and stator connecting conductors 7 extending from the end sides of the stator 1. These three stator connecting conductors 7 are configured to control the three phases. Each stator connecting conductor 7 includes a bundle of wires wrapped with insulating material. This is for connection to a circuit board outside the housing 3. Figure 1 (Not shown in the diagram) The connection is provided with three contact pins 9 protruding through the housing 3. Each stator connection conductor 7 is electrically connected to one of the contact pins 9 by means of a contact element 11.

[0031] Each contact element 11 has a crimping region 13 and a contact region 15. The crimping region 13 has a basic hollow cylindrical shape, in which the end region of one of the stator connecting conductors 7 is crimped, thus forming a mechanical and electrical connection. The crimping can be achieved by means of a thermoforming process, in which heat melts the insulation at the end region of the stator connecting conductor 7 and crimps the end region into the crimping region 13.

[0032] Figure 2 An embodiment of the contact element 11 is shown in a three-dimensional side view. Figure 3 A cross-section of the contact element 11 in the longitudinal direction is shown. These figures are described together below.

[0033] The contact element 11 includes a crimping region 13 and a contact region 15. The contact element is made of a metal sheet by stamping and forming. For example, the contact element 11 can be made of copper or another metal. The crimping region 13 is a rectangular metal sheet region having an outer edge region extending in the longitudinal direction. The metal sheet region is rolled into a hollow cylinder, so that the edge regions overlap each other. The cavity formed by the crimping region 13 is a conductor receiving portion 17 into which the end region of the conductor to be contacted is introduced. After the conductor is introduced, the crimping region 13 is deformed using a suitable tool (e.g., crimping pliers), particularly by pressing it tightly and crimping it against the conductor.

[0034] The contact area 15 extends longitudinally from the crimping area 13. A tab 19 connects the crimping area 13 and the contact area 15. In the example shown, the contact area 15 is a rectangular metal plate area with rounded corners. However, the possible design of the contact area 15 is not limited to this exemplary shape.

[0035] The contact area 15 has a top side 21 and a bottom side 23. A flange 25 protruding on the bottom side 23 surrounds a through groove 27 at the center of the contact area 15. The top side 15 forms a support surface 29 for a contact pin 9, which should be electrically connected to the contact element 11. The support surface 29 is the area of ​​the top side 21 on which the contact pin 9 is placed. Advantageously, the support surface is flat to achieve good and safe electrical contact with the placed contact pin 9. An internal thread 31 is introduced into the wall of the groove 27, which extends along the flange 25 and also partially extends in the area between the top side 21 and the bottom side 23. The internal thread 31 is spaced from the support surface 29 in a direction perpendicular to the extension of the support surface 29, so that the top section of the groove 27 is not threaded. This area is an elastically deformable spring area 33, which widens from the internal thread 31 toward the support surface 29, so that its funnel-shaped cross-sectional profile is curved.

[0036] Contact area 15 can be electrically and mechanically connected to contact pin 9 (in Figure 2 and Figure 3 (Not shown) The contact pin has an external thread 35 at its end. The connection is achieved by screwing the external thread 35 into the internal thread 31.

[0037] Figure 4 A cross-section of a three-dimensional partial illustration of the electric motor is shown, in which the connection between the contact pin 9 extending through the housing 3 and the contact element 11 can be seen.

[0038] The contact pin 9 has a basic cylindrical shape, with a smaller diameter at its end region with external threads 35, thus reducing the stepped cross-section to form a radial support surface 37. When the contact pin 9 is connected to the contact element 11, the external thread 35 engages with the internal thread 31, and the support surface 37 of the contact pin 9 rests against the support surface 29 of the contact element 15. The threaded connection between the external thread 35 and the internal thread 31 is pre-tightened, wherein the spring region 33 of the contact element 15 undergoes elastic deformation and applies pre-tightening. This pre-tightening prevents the threaded connection from loosening due to temperature changes or vibration. The electrical connection between the contact pin 9 and the contact element 11 can be achieved either through the contact of the internal threads 31 and the external threads 35 engaging with each other, or through the contact of the stacked support surfaces 29 and the support surface 37. Final potting is then applied to the stator region. Figure 4 (Not shown) This potting provides additional stability by encapsulating non-rotating components inside the housing, including the stator connection conductor 7 and the contact element 11 connected to the end region of the contact pin 9.

[0039] The connection between the contact pin 9 and the contact element 11 is established at the stator connection conductor 7 of the stator 1 in the housing 3 by passing the contact pin 9 through the opening into the housing and screwing its external thread 35 into the internal thread 31 of the contact element 11 held by the tool by means of rotation until the threaded connection is pre-tightened.

[0040] Figure 5 A cross-section of the contact element 11 connected to the contact pin 9 is shown. The stator connection conductor 7 is pressed into the contact element 11. A seal 39 is provided between the contact pin 9 and the housing 3. The end region of the contact pin 9 with external threads 35 protrudes through the groove 27 of the contact region 15, wherein the external threads 35 engage with the internal threads 31 and the support surface 37 presses against the support surface 29. Due to the preload of the threaded connection, this is accompanied by deformation of the spring region 33.

[0041] The flange 25 and groove 27 in the contact surface 15 of the contact element 11 are formed by flow forming of a metal sheet drawing portion. The metal sheet drawing portion is a partial modification of the metal sheet, which typically begins with a pre-drilled hole and forms a drawn flange around the groove in the metal sheet.

[0042] exist Figure 6 The formation of the groove 27 and the flange 25 is shown in steps (i) to (v).

[0043] In the first step (i), a rotary cylindrical tool with a tapered tip (so-called flow forming tool 41) is placed onto the contact area 15 of the sheet metal. The combination of the feed force and rotation of the flow forming tool 41 generates frictional heat and causes plastic deformation, see step (ii). Unlike conventional drilling, flow forming (also known as hot drilling) is not a cutting process. Rather, the flow forming tool 41 causes material to be extruded and displaced, thus forming an opening (see step (iii)), which, as the flow forming tool penetrates deeper, forms a groove 27 with a flange 25. The material in the opening area is extruded to the bottom side, thus forming a sleeve-shaped flange 25 on the bottom side. After the flow forming tool is removed, the bottom side of the groove 27 is radially defined by the flange 25, see step (iv). The length of the flange 25 can be three to four times the thickness of the sheet metal. Subsequently, in a further step (v), an internal thread 31 is formed into the groove 27, which also extends along the flange 25. This can be achieved using the threading tool 43, either by cutting or by deformation without cutting.

[0044] As shown in partial illustration (vi), when the contact pin 9 is connected to the contact element 11, its external thread 35 engages with the internal thread 31.

[0045] The features set forth above and in the claims, and as can be obtained from the accompanying drawings, can be advantageously implemented not only individually but also in various combinations. The invention is not limited to the described embodiments, but can be modified in various ways to the extent possible to those skilled in the art.

[0046] List of reference numerals

[0047] 1 stator

[0048] 3 shells

[0049] 7 Stator Connecting Conductors

[0050] 9 contact pins

[0051] 11 Contact Elements

[0052] 13 Crimping Area

[0053] 15 contact areas

[0054] 17 Conductor receiving section

[0055] 19 stitches

[0056] 21 Top Side

[0057] 23 Bottom side

[0058] 25 flange

[0059] 27 grooves

[0060] 29 support surfaces

[0061] 31 internal thread

[0062] 33 Spring Area

[0063] 35 external thread

[0064] 37 Support Surface

[0065] 39 Seals

[0066] 41 Flow forming tools

[0067] 43 Threading tools.

Claims

1. A contact element (11) having: a crimping region (13) designed for crimping onto an electrical conductor; and a contact region (15) having a through groove (27) radially defined by a flange (25) on the underside (23) of the contact region (15), wherein, The groove (27) has an internal thread (31).

2. The contact element (11) according to claim 1. in, The groove (27) and the flange (25) are formed by the flow-formed metal sheet drawing portion.

3. The contact element (11) according to any one of the preceding claims. in, The contact area (15) has a top side (21) that forms a support surface (29) for contacting the pin (9), wherein the internal thread (31) is spaced apart from the support surface (29) in a through direction perpendicular to the top side (21).

4. The contact element (11) according to any one of the preceding claims. in, The internal thread (31) extends along the entire length of the flange (25).

5. The contact element (11) according to any one of claims 3 or 4. in, The spring region (33) between the support surface (29) and the internal thread (31) is capable of elastic deformation.

6. The contact element (11) according to claim 5. in, The spring region (33) is radially widened toward the support surface (29).

7. The contact element (11) according to any one of the preceding claims. The contact element is integrally formed from a metal plate.

8. The contact element (11) according to any one of the preceding claims. The contact element is made of copper.

9. The contact element (11) according to any one of the preceding claims. in, The crimping area (13) is connected to the contact area (15) via a tab (19), and the crimping area (13) forms a cavity extending in the longitudinal direction as a conductor receiving part (17), and the edge regions extending in the longitudinal direction of the crimping area (13) overlap each other.

10. The contact element (11) according to any one of the preceding claims. in, The contact area (15), which extends longitudinally from the crimping area (13), is a metal plate area with a basic rectangular or circular shape.

11. A stator assembly having a stator (1) comprising at least one stator connecting conductor (7), wherein, A contact element (11) according to any one of the preceding claims is tightly fitted at the end region of the stator connecting conductor (7), wherein the contact element (11) is electrically connected to a contact pin (9), and the contact pin (9) has a contact pin end with an external thread (35) that engages with the internal thread (31) of the contact element (11).

12. The stator assembly according to claim 11, in, The contact pin (9) has a support surface (37) that protrudes radially from the external thread (35) and abuts against the support surface (29) of the contact element (11).

13. The stator assembly according to claim 11 or 12, in, The external thread (35) and the internal thread (31) engage with each other as a threaded connection, so that a preload is applied to the threaded connection.

14. A method for manufacturing a contact element (11), said contact element having a crimping region (13) and a contact region (15), wherein, The method includes: forming a groove (27) in the contact area (15) by means of flow forming and a flange (25) that radially defines the groove (27) on the bottom side of the contact area (15), and forming an internal thread (31) in the groove (27).

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