Line assembly for electrically connecting a first contact element to a second contact element

Abstract

The invention relates to a line assembly for electrically connecting a first contact element to a second contact element, comprising a first terminal region for connecting to the first contact element and a second terminal region for connecting to the second contact element. The first and second terminal region are arranged on respective opposing ends of a busbar which connects the terminal regions, and the first and second terminal region have a respective plurality of elastically deformable resilient contact tongues which are designed and arranged such that the contact tongues clamp the respective connected contact element with a holding force in an electrically conductive manner.

Description

[0001] Line arrangement for electrically connecting a first contact element to a second contact element

[0002] The present invention relates to a line arrangement for electrically connecting a first contact element to a second contact element, as well as to a separately excited synchronous machine comprising the line arrangement.

[0003] The increasing demand for electrically and partially electrically powered machines, especially vehicles, makes efficient production and, above all, efficient assembly of their components increasingly important.

[0004] One example of an electrical machine is a separately excited synchronous machine (SESM). During operation, the rotor winding is typically energized with direct current, generating a rotor-side magnetic field that interacts with a stator-side magnetic field. This causes the rotor to rotate.

[0005] To energize the exciter, i.e. the field windings of the rotor, current must be supplied to it, for example from the power electronics (LE), in order to generate the rotor-side magnetic field.

[0006] The power electronics and the electrical machine are often manufactured separately and only later contacted or connected by conductive elements. Insulated and bent copper or aluminum rails, also known as busbars, are used for this purpose. A particular advantage of busbars is that they are better suited to automated assembly than conventional flexible cable connections. In robotic production lines, the rigid busbars can be installed more easily and with greater process reliability than flexible cable connections. To date, there has been a wide variety of components for connecting the motor elements to the power electronics and energy storage systems, which cannot be used interoperably across the board.

[0007] In addition, common cable arrangements, such as cables or simple metal rails, require the use of clamping or crimping tools, making blind installation difficult or even impossible. At the same time, common cable arrangements cannot guarantee tolerance compensation for structural deviations.

[0008] The use of tools to connect engine parts with, for example, the power electronics or energy storage systems simultaneously increases the required design or installation space of the electrical machine, as space must be left for the tool(s).

[0009] In addition, the “crimped” or jammed contact points between, for example, power electronics and the excitation windings of a rotor are more susceptible to fretting corrosion, which can shorten the service life of an electrical machine.

[0010] The object of the present invention is to provide a line arrangement for a connection between a first and a second contact element, which at least partially overcomes the disadvantages mentioned above.

[0011] This object is achieved by the line arrangement according to claim 1.

[0012] In a first aspect, the present invention provides a cable arrangement for electrically connecting a first contact element to a second contact element, comprising a first connection region for connection to the first contact element and a second connection region for connection to the second contact element. The first and second connection regions are each arranged at opposite ends of a cable rail connecting the connection regions and have a plurality of elastically deformable, resilient contact tongues, which are designed and arranged such that they electrically clamp the connected contact element with a holding force.

[0013] A conductor arrangement can be an element made of a material suitable for conducting electrical current, for example, in the form of a sheet of copper, gold, or aluminum formed according to the invention. The conductor arrangement according to the invention can thus be used for electrical connections.

[0014] The cable arrangement according to the invention has a first and second connection area to which contact elements of different types can be connected. The designation "first" and "second connection area" can be used variably for the respective connection ends of the cable arrangement.

[0015] A first contact element that can be electrically connected to the cable arrangement according to the invention at a first connection area can be, for example, a current pin. A current pin can be designed in the form of a pin that protrudes, for example, from the power electronics of a separately excited synchronous machine and with which the current emanating from the power electronics can be transmitted.

[0016] A second contact element that can be contacted with the cable arrangement according to the invention in a second connection area is, for example, the end of a flat wire. Flat wires are also used in an exciter coil or winding. In a separately excited synchronous machine, the excitation winding in the rotor must be energized to generate a magnetic field that interacts with the magnetic field of the stator and enables the movement of the machine. Power electronics is a central element of electric drives and ensures, for example, that a continuous increase in speed is possible by appropriately energizing the excitation windings.

[0017] As mentioned above, the first and second connection areas are each arranged at opposite ends of a conductor rail connecting the two connection areas. The conductor rail can be made of the same or a differently conductive material as the connection areas. The conductor rail can be either straight or angled. A conductor rail according to the invention is longer than it is wide and can have a length between 2 and 10 cm.

[0018] The first and second connection areas according to the invention, each located at the opposite end of the conductor rail, have a plurality of elastically deformable contact tongues. The contact tongues can be designed such that they are movable in at least one direction, i.e., resiliently or elastically deformable, for example, by selecting a material thickness for the contact tongues at which they yield to a compressive force from one direction. The contact tongues can establish the primary electrical connection between the connection area and the contact element.

[0019] The contact tongues according to the invention are designed and arranged in such a way that they clamp the contact element(s) in an electrically conductive manner with a holding force. The resilient contact tongues can create a frictional connection between the connection areas and the contact elements.

[0020] The cable arrangement according to the invention ensures blind installation or joining of components of an electrical machine. The absence of clamping or crimping points can reduce fretting corrosion in an electrical machine. This also results in a smaller installation space for the machine. In a first embodiment of the cable arrangement according to the invention, the connection areas are designed as closed eyelets. In this embodiment, the contact tongues are arranged on the eyelet circumference, defining a connection area that is smaller than the eyelet width. As a result, the contact tongues on the eyelet circumference can build up a holding force that clamps and thus fixes the contact element. The contact tongues on the eyelets shaped in this way can ensure initial tolerance compensation, for example during blind assembly of the individual machine parts.

[0021] In a further embodiment, the first connection area is designed in the form of a round eyelet, on the circumference of which contact tongues are arranged in a crown-like manner and extend radially inwardly from the edge of the eyelet. The angle of inclination of the contact tongues to the edge of the eyelet can be designed such that the contact tongues touch in the center of the tongue, or such that the contact tongues do not touch but only converge concentrically inward. This can depend on the elasticity of the manufacturing material of the cable arrangement, but also on the size or payload of the machine in which the cable arrangement is installed, or of the contact element that is connected to the cable arrangement.

[0022] In a further embodiment, the second connection area is designed in the form of a rectangular eyelet with inwardly inclined contact tongues on two opposite longitudinal sides. The contact tongues can have a slanted, free end to increase the holding force exerted on the contact element.

[0023] In a further embodiment of the line arrangement according to the invention, the contact tongues are designed as finger-like and / or U-shaped contact tabs. The finger-like contact tongues can be designed as insulated free elements that are connected to one another via a lower part and thus accommodate the contact element. The contact tongues can also be provided as U-shaped tabs that can protrude into the interior of the eyelets described above.

[0024] In a further embodiment, a connection area is designed such that the plurality of U-shaped contact tabs are arranged in pairs opposite one another on the opposite long sides of the rectangular eyelet for receiving a flat second contact element. In a cross-sectional view, the contact tabs in this embodiment can be bent towards one another in a heart shape. Several contact tabs can be arranged next to one another on each long side of the eyelet, with the opposite long side correspondingly having the same number of contact tabs, resulting in a symmetrical shape in cross-section. This allows a flat connection area to be realized in which a flat contact element can be received centrally.

[0025] In a further embodiment, a connection region of the line arrangement is designed such that the finger-like contact tongues on the round eyelet are configured to receive a cylindrical or prismatic contact element. The finger-like contact tongues can each be round on an inner edge of the eyelet so that a round or cylindrical contact element can be received. However, the finger-like contact tongues can also be designed such that they can receive a polygonal or prismatic-shaped contact element by having the finger-like contact tongues on an inner edge of the eyelet each being straight, with the inner edge of the eyelet correspondingly having a polygonal or prismatic shape like the corresponding contact element.

[0026] In a further embodiment, the cable arrangement is designed such that the second connection area can clamp a flat wire and the first connection area can clamp a bolt. A flat wire can be a flat wire that comes from the coils of an exciter of an electrical machine. The flat wire can have a material thickness of up to 0.8 mm, but preferably up to 0.5 mm. The bolt can be a current bolt that comes from the power electronics of an electrical machine. The current bolt can carry a current of between 10 and 30 A per mm 2 related to the cross-section of the bolt and the flat wire and between 4 to 6 A per mm 2 between the bolt or the flat wire and the busbar according to the invention. Accordingly, the outer diameter of the eyelets of the first and second connection areas can be dimensioned according to the current intensity of the current to be conducted.

[0027] In a further embodiment, the conductor rail connecting the two connection areas has a flattened, particularly rectangular, cross-section, so that the conductor rail is flexible in the plug-in direction of the contact elements. The conductor rail can have flat or rounded side edges. The conductor rail is flexible or resiliently movable in the plug-in direction, i.e., in the connection direction of the contact element, which can be achieved by a correspondingly low thickness of the conductor rail.

[0028] The conductor rail can have a thickness of up to 0.8 mm, but preferably up to 0.5 mm, with a length of 2-10 cm. It is recommended to keep the conductor rail as short as possible. The conductor rail is flexible in the thickness direction compared to its length direction. Accordingly, the conductor element can be elastically deformed in the axial direction relative to the rotor axis of an electrical machine, or can spring in this direction. At the same time, the conductor rail is rigid in the radial direction.

[0029] The spring-loaded contact tongues and the spring-loaded conductor rail allow for double tolerance compensation, which facilitates blind installation or joining of the machine components.

[0030] In a further aspect, the present invention provides a separately excited synchronous machine (SMM) in which an excitation winding is connected to power electronics by a cable arrangement according to the invention. The contact tongues according to the invention allow the first connection area to clamp a current pin of the power electronics, and the second connection area to clamp a flat wire of a power transmission device that interacts with the excitation winding of a rotor of a separately excited synchronous machine, either in a contact-like or contactless manner.

[0031] The power transmission device can be designed in the form of a slip ring transformer or in the form of an inductive transformer.

[0032] Preferably, the cable arrangements are arranged in parallel and in the same plane between the motor and the power electronics. Furthermore, they can be arranged as close as possible to the axis of rotation. In this exemplary embodiment, two ends of a current transmission device for an excitation winding are connected to two adjacent current pins of a power electronics system. This can be sufficient to energize the coils to generate a magnetic field, which can trigger a uniform rotational movement of the separately excited synchronous machine.

[0033] The spring-loaded design of the connection areas and the busbar as described above enables blind connection with double tolerance compensation of the excitation device of a motor with the power electronics.

[0034] Further aspects and features of the present invention emerge from the dependent claims, the accompanying drawings and the following description of embodiments.

[0035] Embodiments of the invention will be described by way of example and with reference to the accompanying drawings. They show:

[0036] Fig.1 a plan view of a line arrangement according to the invention with a first and second connection area

[0037] Fig. 2a shows a cross section of a first connection area in a first

[0038] Embodiment Fig. 2b shows a cross section of a second connection area in a first embodiment

[0039] Fig. 2c shows a cross section of a second connection area in a second embodiment and connected contact element Fig. 3 shows a cross section of a conductor rail in a first, second and third embodiment

[0040] Fig. 4 a schematic side view for positioning the

[0041] Cable arrangement in an electrical machine

[0042] Fig. 1 shows a plan view of a cable arrangement 10 according to the invention. A first connection region 1 is connected to a second connection region 2 via a cable rail 3. The first connection region is equipped with contact tongues 4a, and the second connection region is correspondingly equipped with contact tongues 4b. The contact tongues are designed to be elastically deformable, i.e., resilient or flexible. The direction of extension of the contact tongues in the first connection region 1 and in the second connection region 2 is shown by the double arrows in Fig. 1. Accordingly, the contact tongues 4a and 4b are designed to be deformable, or elastic, at least outwardly, such that they form an inward-acting holding force that frictionally connects a first and second contact element to the cable arrangement.

[0043] The simple arrows in Fig. 1 indicate the connection or plug-in direction in which the conductor element is installed in an electrical machine. The conductor element is plugged from the paper plane onto the contact elements to be electrically connected.

[0044] Furthermore, the simple arrows of the plug-in direction in Fig. 1 also show the possibilities for connecting the respective first and second connection areas 1 and 2 to corresponding contact elements 5 and 6, which will be referred to again later in the description of Fig. 2c and Fig. 4. Fig. 1 shows a first exemplary embodiment in which the first and second connection areas are each designed as eyelets. The first connection area 1 is in the form of a round eyelet 1b, the second contact area 2 in the form of a square eyelet 2b. The shape of the eyelets is not limited to these embodiments; rather, the shape of the eyelets can be adapted to the respective contact element to be connected.

[0045] The eyelets 1b and 2b are provided with contact tongues 4a and 4b. In this embodiment, the contact tongues each define a first and second inner connection region 1a and 2a, whose inner circumference is smaller than the circumference of the eyelets 1b and 2b, thereby generating a holding force and allowing the contact element to be received.

[0046] Fig. 2a shows an embodiment of the first contact area 1 in a cross-sectional view AA. The conductor rail 3 on the left in Fig. 2a is connected to a first connection area 1, which is designed as a round eyelet 1b. Crown-like contact tongues 4a are formed on the round eyelet. These can be formed over the entire radial surface of the eyelet or extend only over an inner edge of the eyelet.

[0047] The contact tongues in the embodiment of Fig. 2a are inclined inward. Accordingly, each contact tongue defines an angle of inclination at the connection to the eyelet, resulting in an inner connection area 1a that has a smaller circumference than the eyelet 1b, thus providing a contact element with a holding force and an electrically conductive connection.

[0048] Fig. 2b shows a BB cross-section of a first embodiment of the second connection region 2. The second connection region is designed in the form of a rectangular eyelet 2b. In this embodiment, finger-like contact tongues 4b are shown on the surface of the eyelet 2b or on its inner edge. These contact tongues are inclined towards one another and define an inner connection region 2a that is smaller than the circumference of the eyelet 2b. The contact tongues 4b of the second connection region 2 are arranged in pairs and opposite one another on a long side of the rectangular eyelet 2b.

[0049] According to a further embodiment, the contact tongues 4b of the second connection area 2 can be designed in the form of U-shaped contact tabs. The inwardly bent contact tabs are connected at one end to the rectangular eyelet, at least at an inner edge, and the bent contact tabs thus define an inner connection area 2a that is smaller than the circumference of the eyelet 2b.

[0050] According to a further embodiment, the plurality of U-shaped contact tabs arranged opposite one another in pairs are designed as contact tongues 4b such that they can accommodate a flat contact element 5. Fig. 2c shows a cross section BB of a second embodiment of the second connection region 2, wherein a flat contact element 5 is connected.

[0051] In Fig. 2c, the second connection area 2 is designed in the form of a rectangular eyelet 2b. U-shaped contact tabs are attached to the inner side of the eyelet as contact tongues 4b.

[0052] The contact tabs are shaped in such a way that they define an inner contact area 2a through their inwardly bent free end, which can be elastically deformed in the direction of the double arrow in Fig. 2c. Thus, the contact tabs can clamp a flat contact element 5 through an inwardly acting holding force and electrically connect it.

[0053] Figs. 3a-c show cross sections BB of possible embodiments of the conductor rail 3. The conductor rail serves to connect the first connection area 1 to the second connection area 2 and is flexible in the direction of the arrow in Figs. 3a-c. The direction of the arrow corresponds to the connection or plug-in direction in which the cable arrangement is attached.

[0054] Fig. 3a shows a conductor rail with an oval cross-section; accordingly, the conductor rail has a curved surface in plan view. Fig. 3b shows a conductor rail with a rectangular cross-section. Fig. 3c shows a cross-section of a conductor rail with a straight surface in plan view, but a curved shape at its flat ends.

[0055] Figure 4 shows a schematic side view of the installation of the cable arrangement according to the invention in an electrical machine. In this exemplary embodiment, two cable arrangements 10 each connect a current pin 6 of a power electronics system to a supply line 5 for a current transmission device of an excitation winding of an electrical machine.

[0056] In this exemplary embodiment, a second connection area 2 is plugged onto the ends of a flat wire of a field winding as a second contact element 5 in the direction of the arrow indicated in Fig. 3. The first contact element 6, in the form of a current pin of a power electronics unit, is also plugged into the first connection area in the direction of the arrow. This allows the field winding to be electrically connected to the power electronics unit, thereby enabling a smaller installation space in the electrical machine.

[0057] Reference numeral first connection area a first inner connection area b first eyelet second connection area a second inner connection area b second eyelet

[0058] Conductor rail a, 4b Contact tongues Second contact element First contact element 0 Cable arrangement

Claims

Amended patent claims 1. A cable arrangement (10) for electrically connecting a first contact element (6) to a second contact element (5), comprising: a first connection region (1) for connection to the first contact element (6), wherein the first connection region (1) comprises a round eyelet, on the circumference of which contact tongues (4a) arranged in a crown-like manner are formed, which extend radially inwards and are inclined from the edge of the eyelet;and a second connection area (2) for connection to the second contact element (5), wherein the second connection area (2) comprises a rectangular eyelet which has contact tongues (4b) inclined towards one another in pairs on two oppositely arranged longitudinal sides, wherein the first (1) and second connection area (2) are each arranged at opposite ends of a conductor rail (3) connecting the connection areas and the plurality of elastically deformable, resilient contact tongues (4a, 4b) are designed and arranged such that they clamp the connected contact element (5, 6) in an electrically conductive manner with a holding force; 2. Cable arrangement (10) according to claim 1, wherein the connection areas (1, 2) are designed as closed eyelets (1b, 2b) and the contact tongues (4a, 4b) are arranged on the eyelet circumference and define a connection area (1a, 2a) which is smaller than the eyelet width.

3. Cable arrangement (10) according to one of the preceding claims, wherein the contact tongues (4a, 4b) are designed as finger-like and / or as U-shaped contact tabs.

4. Cable arrangement (10) according to claim 3, wherein the plurality of U-shaped contact tabs for receiving a flat contact element are formed in pairs opposite one another on the opposite longitudinal sides of the rectangular eyelet.

5. Cable arrangement (10) according to one of the preceding claims, wherein the finger-like contact tongues (4a) on the round eyelet are designed to receive a cylindrical or prismatic contact element.

6. Cable arrangement (10) according to one of the preceding claims, wherein the cable rail (3) connecting the two connection areas has a flattened, in particular rectangular, cross-section, so that the cable rail is flexible in the plug-in direction of the contact elements.

7. Separately excited synchronous machine, characterized in that a current transmission device for an excitation winding is connected to a power electronics unit by a line arrangement (10) according to one of claims 1 to 6.

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