Slip ring assembly and contact element carrier for this

Abstract

Slip ring assembly with: a conductor track carrier (1) and a contact element carrier (3) which are rotatably held relative to each other about a common axis, wherein the conductor carrier (1) has at least one annular conductor track (5) arranged around the common axis, wherein the contact element carrier (3) has at least one contact element (7), wherein the contact element (7) comprises an elastic element (9) and a spherical element (11), wherein the spherical element (11) is elastically pressed against the conductor track (5) by the elastic element (9) in a direction substantially perpendicular to the common axis, is in contact with it during operation and rolls along the conductor track (5); the contact element (7) further comprises: a circuit board (13) with at least one contact pin (15) attached to it, wherein the contact pin (15) has an electrically conductive sheath (17) in which the elastic element (9) and the spherical element (11) are held.

Description

[0001] The invention relates to the technical field of electrical connectors and transmission elements. In particular, the invention relates to a slip ring arrangement for transmitting electrical energy and / or signals between two components that are rotatable relative to each other. Such arrangements are used, for example, in robotics, medical devices, wind turbines, or the automotive industry.

[0002] Slip ring arrangements are known in the art for transmitting electric current between a stationary part (stator) and a rotating part (rotor). To overcome the disadvantages of conventional sliding contacts, such as wear, abrasion, and high friction, solutions based on rolling contacts have been developed.

[0003] Document US 5,575,664, for example, discloses a ball-contact rotary connector in an axial design. In this design, pairs of printed circuit boards are stacked axially, with conductive rings on the facing surfaces being electrically connected by interposed balls.

[0004] The necessary contact pressure is generated by a retaining element that axially compresses the entire stack. This design is specifically intended for stacked assembly and is not suitable for a simple radial plug-in connection between the rotor and stator.

[0005] Document CN 115548812A describes a radial current transmission structure in which conductive spheres are pressed radially inwards against slip rings by individual springs. While this arrangement also uses rolling contacts, it does not explicitly address the challenges that arise during the axial assembly (insertion) of the components. In particular, the forces acting on the contact element holders and the resulting risk of damage are not discussed.

[0006] In known radial arrangements where a rotor is inserted into a stator, the contact elements encounter a chamfer on the rotor and are pushed radially outwards. If this displacement process is not low-friction, significant insertion forces can occur. These forces can stress the delicate retaining structures of the contact elements, such as contact pins, and lead to bending or damage, jeopardizing the reliability of the entire assembly. Therefore, it is common practice to permanently join the two parts, rotor and stator.

[0007] Slip ring systems are usually delivered as fully assembled units, so that plugging them together during installation in the end device is not possible.

[0008] Based on this prior art, the invention aims to provide a slip ring arrangement that overcomes the disadvantages of the prior art.

[0009] In particular, a durable, low-wear, and reliable electrical connection should be created, characterized by exceptionally simple and robust assembly. The forces occurring during the insertion of the components should be minimized to reliably prevent damage to the contact elements.

[0010] This problem is solved by a slip ring arrangement having the features of claim 1 and by a contact element carrier according to claim 7. The dependent claims relate to further advantageous embodiments of the invention.

[0011] The slip ring arrangement according to the invention comprises a conductor track carrier and a contact element carrier, which are rotatable relative to each other about a common axis and axially pluggable into one another. The conductor track carrier has at least one annular conductor track. The contact element carrier has at least one contact element which uses a rolling contact instead of a sliding contact. For this purpose, the contact element comprises a spherical element which is elastically pressed against the conductor track by an elastic element in a direction substantially perpendicular to the common axis.

[0012] The special feature of the invention is that the contact element and a chamfer on the conductor carrier are designed and coordinated in such a way that the ball element performs a defined rolling movement transverse to the circumferential direction of the conductor track during the axial insertion process.

[0013] While the conductor carrier is pushed into the contact element carrier, the ball element is forced to deflect radially, approximately outwards, but then rolls on the surface of the conductor carrier until it reaches the associated conductor track.

[0014] The crucial technical effect is that this rolling motion drastically reduces frictional resistance during insertion. The axial force required to join the two components is therefore minimal. This prevents excessively high bending or shear forces from being exerted on the contact element's holder, particularly on a carrier pin. Bend of the pin or damage to its solder joint on a circuit board is thus reliably prevented. The slip ring assembly can therefore be connected easily, securely, and repeatedly, like a robust connector, significantly improving ease of assembly and overall reliability.

[0015] Furthermore, the contact element is advantageously implemented as a pre-assembled unit, for example as a spring-loaded pin ("omniball pin") that encloses an electrically conductive sheath in which the elastic element and the ball element are held. This enables a very compact and integrated design.

[0016] During operation, the ball element rolls along the conductor track, thus establishing the electrical contact. This rolling contact significantly reduces friction and wear compared to conventional sliding contacts.

[0017] Furthermore, the contact element comprises a circuit board with at least one contact pin mounted on it. This contact pin is designed such that it has an electrically conductive sheath in which the elastic element and the ball element are held. This enables a very compact and integrated design, in which the contact element can be implemented as a pre-assembled unit, for example as a spring-loaded pin ("pogo pin" or "omniball pin").

[0018] Preferred embodiments of the invention are defined in the dependent claims. Fig. 1A: is a front view of a slip ring arrangement according to the invention. Fig. 1B: is a sectional view (AA) of the slip ring arrangement according to the invention. Fig. 1C: is a perspective view. Fig. 2A: is a detailed view of the conductor track carrier (rotor) designed as a spindle in a front view. Fig. 2B: is a section view (CC). Fig. 3A: is a detailed view of the contact element carrier (stator) designed as a sleeve in a sectional view (AA). Fig. 3B: is one to Fig. 3A corresponding perspective view. Fig. 4: is a sectional view of a contact element.

[0019] Fig. Figure 1C shows a perspective view of the slip ring arrangement according to the invention. The arrangement essentially comprises a conductor carrier 1, here configured as a rotor or spindle, and a contact element carrier 3, here configured as a stator or sleeve. The conductor carrier 1 and the contact element carrier 3 are designed to be arranged coaxially and to be axially plugged into one another.

[0020] Fig. Figure 1A shows the slip ring arrangement according to the invention from the direction parallel to the axis of rotation from the side of the contact element carrier 3, where in this embodiment a 10-pin connector is formed.

[0021] The conductor track carrier 1 comprises, as shown in Fig. 2A and Fig. Figure 2B shows several ring-shaped conductor tracks 5 located on its outer circumference. Fig. Figure 2B illustrates that a chamfer 4 is provided at the front end of the conductor carrier 1, which facilitates insertion into the contact element carrier 3.

[0022] In the illustrated embodiment, the starting chamfer 4 is designed such that, when the conductor carrier 1 is inserted into the contact element carrier 3, it engages respective ball elements 11 of a Fig. The contact pin 15, shown in detail in section 4, is pushed back so that the ball elements 11 then roll on the outer circumferential surface of the conductor carrier 1 and move along an axis of rotation, i.e., the insertion direction, rolling until they reach their assigned conductor track 5. In this way, excessive axial forces are prevented from being exerted on the contact pins 15, which here serve as contact elements 7. This is particularly important when used according to Fig. Otherwise, if the contact pins 15 were soldered onto the circuit board 13, this would easily lead to a deformation of the contact elements 7 or even damage or break off a soldered connection with the circuit board 13.

[0023] The contact element carrier 3 has several contact elements 7 mounted on the circuit board 13. Each contact element 7 is implemented as a unit comprising a contact pin 15 with a ball element 11 and an elastic element 9 – for example, a coil spring – typically in the form of an “omniball pin”, as shown in Fig. Figure 4 shows that the invention is not limited to this, and contact pins 15 with a spherical element from other sources can be used. Furthermore, the elastic element is not necessarily a coil spring. Depending on the dimensions, a leaf spring or a rubber element can also be used, particularly in conjunction with a conductive sheath 17, so that an electrically conductive connection is ensured from the conductor track 5, via the spherical element 11 to the sheath 17 and from there to the circuit board 13.

[0024] The elastic element 9 pushes the spherical element 11 out of the shell 17 and presses it elastically against the associated conductor track 5 in the operating state.

[0025] During assembly, when the conductor carrier 1 is inserted into the contact element carrier 3, the ball elements 11 encounter the chamfer 4. Due to the axial feed movement, the ball elements 11 are forced to move radially outwards against the force of the elastic element 9.

[0026] The spherical elements 11 then roll on the surface of the conductor carrier 1 in the direction of the axis of rotation, i.e., the longitudinal axis or the insertion direction. The spherical element 11 rotates about an axis that is essentially tangential to the surface of the conductor carrier 1.

[0027] Since the rolling friction resistance is significantly lower than the sliding friction resistance, the axial force required for insertion is minimized. This protects the contact elements 7 and their mounting on the circuit board 13 from excessive lateral forces.

[0028] Once the conductor carrier 1 has reached its end position, the ball elements 11 lie on the respective conductor tracks 5. In normal operation for the rotary transmission, the ball element 11 then rolls circumferentially on the conductor track, thus establishing a low-wear electrical contact.

[0029] In the embodiment shown, the arrangement essentially comprises a conductor carrier 1, which here is designed as a rotor or spindle, and the contact element carrier 3, which here is designed as a stator or sleeve 8.

[0030] The conductor carrier 1 and the contact element carrier 3 are designed to be arranged coaxially to each other and rotatable relative to each other about a common axis.

[0031] In a modification of the embodiment shown, it is also possible to form the slip rings or conductor tracks on the inside of a sleeve and the contact elements 7 on the spindle.

[0032] Likewise, both elements can have conductor tracks and contact elements 7.

[0033] Ultimately, it only depends on the relative rotation of the two elements, conductor carrier 1 and contact element carrier 3, without it being important which of these elements actually rotates in space, or whether both elements rotate at different speeds and / or directions relative to each other.

[0034] As in Fig. As shown in 3B, a connector 10 is formed at one axial end of the contact element carrier 3, here for example a 10-pin connector 10.

[0035] As in Fig. 1B and Fig. 3A, the sectional views of Fig. 1A and Fig. As can be seen in Figure 3B, the conductor carrier 1 can be inserted into the contact element carrier 3. Relative rotation is supported by a ball bearing 6, which is arranged between the conductor carrier 1 and the housing of the contact element carrier 3.

[0036] In a preferred embodiment, the conductor carrier 1 is designed as a spindle and the contact element carrier 3 as a sleeve 8.

[0037] The conductor carrier 1 comprises a rotor shaft on which several annular conductor tracks 5, also referred to as sliding tracks, are arranged. These conductor tracks 5 extend around the outer circumference of the conductor carrier 1.

[0038] As it is in Fig. As shown in Figure 2A, insulators 12 or insulating surface sections of the conductor carrier 1 are provided between the individual conductor tracks 5 to electrically separate the conductor tracks 5 from one another. The conductor tracks 5 are preferably made of a highly conductive material, such as a gold-plated copper alloy, to ensure low contact resistance.

[0039] The conductor tracks can be planar or concave in cross-section along the axis of rotation, with the shape and width of the conductor tracks preferably being adapted to the shape and radius of the spherical elements 11 of the associated contact element 7.

[0040] The contact element carrier 3 shows, as in the Fig. 1 and Fig. Figure 4 shows several contact elements 7. At least as many contact elements 7 as conductor tracks 5 are provided, with each contact element 7 being assigned to a conductor track 5.

[0041] However, it is preferred to contact each conductor track 5 by two or more contact elements 7, which access the conductor track at various points distributed around its circumference to increase contact reliability. An excessively large number of contact elements 7 is disadvantageous, however, because it increases frictional forces and wear on the conductor tracks 5. Therefore, two or three contact elements 7 are preferably provided for each conductor track 5.

[0042] Each contact element 7 is, as shown in the section view, Fig. Figure 4 shows in detail the embodiment as a single unit comprising a spherical element 11 and an elastic element 9. In the illustrated embodiment, the contact element 7 is realized as an "omniball pin" 15. This pin represents a contact pin 15. It comprises an electrically conductive sheath 17 in which the spherical element 11 and the elastic element 9 are held.

[0043] The elastic element 9 pushes the spherical element 11 out of the shell 17 and presses it elastically against the associated conductor track 5. The contact pressure is applied in one direction essentially perpendicular to the common axis of rotation of the arrangement.

[0044] During a relative rotation between conductor track carrier 1 and contact element carrier 3, the ball element 11 rolls on the surface of the conductor track 5. This results in very low frictional resistance and significantly minimizes the wear of both the ball element 11 and the conductor track 5.

[0045] As it is in Fig.As can be seen in Figure 3A, the contact elements 7 are mounted on a circuit board 13. This circuit board 13 is part of the contact element carrier 3 and serves for the electrical connection of the contact elements 7. The electrical connection is made from the conductor track 5 via the spherical element 11 and the conductive sheath 17 of the contact pin 15 to the circuit board 13. The elastic element 9 itself does not necessarily have to be current-carrying.

[0046] The conductor track carrier 1 and the contact element carrier 3 can be plugged into each other in the direction of the common axis.

[0047] When the conductor carrier 1 is inserted into the contact element carrier 3, the ball elements 11 meet the chamfer 4 on the conductor carrier 1 and are pressed radially outwards against the force of the elastic element 9.

[0048] The embodiment shown in the figures represents a preferred embodiment of the invention, offering a compact, robust, and low-wear solution for rotating current and signal transmission. The use of standardized, spring-loaded contact pins with a ball element 11 simplifies manufacturing and assembly.

[0049] In the preferred embodiment, the conductor carrier 1 is hollow and the conductors are electrically contacted from the inside of the conductor carrier, with the electrical signals or the electrical current being carried on via a cable at an axial end of the conductor carrier.

[0050] This is not strictly necessary. It is also possible not to form the conductor track 5 as a closed ring, but to provide a gap through which the electrical signals are then guided in an axial direction. The short-term loss of contact of a contact element 7 along the conductor track 5 when crossing the gap is negligible if several contact elements 7 access one conductor track 5, so that sufficient electrical contact is always ensured.

[0051] In the preferred embodiment shown in the figures, the conductor carrier 1 is held at its front end by a groove 21 when fully inserted into the contact element carrier 3 by a corresponding spring of the contact element carrier 3. This is also only a preferred embodiment, and the invention is not limited to such a tongue-and-groove connection.

[0052] In a preferred alternative embodiment, the conductor tracks 5 are concave in cross-section along the axis of rotation, the shape of the conductor tracks 5 corresponding to that of the spherical elements 11. In this way, the spherical elements 11, which engage with the conductor tracks 5, create a tongue-and-groove connection between the conductor track carrier 1 and the contact element carrier 3, holding the two elements together axially. By appropriately dimensioning the elastic elements 9 and the number of conductor tracks 5 and contact elements 7, respectively, it is possible to precisely adjust the holding force in the axial direction.

[0053] The concave shape of the conductor tracks is a preferred design. Alternatively, the design with groove 21 as described in the paragraph above can be used.

[0054] Alternatively, instead of the concave shape, another geometric shape can be used, e.g., a V-shaped indentation with 90° flanks. V-shaped indentations have the advantage that the spherical element contacts conductor 5 at two points, which is desirable for reliable, low-noise, and uninterrupted transmission.

[0055] This means that at least one conductor track 5 is concave in cross-section in the direction of the common axis or axis of rotation, so that the conductor track 5 forms the annular groove 21, and wherein at least one contact element 7 engages in the groove 21 as a spring element.

[0056] Preferably, a plurality of circumferentially spaced contact elements 7 are provided, which engage in the groove 21 formed by the conductor track 5.

[0057] Preferably, several conductor tracks 5 and several contact elements 7 are arranged along the common axis.

[0058] Furthermore, the contact element carrier 3 can be designed such that a plurality of contact elements 7 contact a conductor track 5, wherein the plurality of contact elements 7 are spaced apart around the circumference of the contact element carrier 3 in order to guide the two carriers 3, 5 relative to each other when plugged in.

[0059] In a variant not shown, the conductor carrier 1 is designed in the form of a sleeve, the conductor tracks 5 extend around the inner circumference, and the contact element carrier 3 is designed as a spindle.

[0060] In the embodiment shown in the figures, the contact element carrier 3 is designed in the form of a sleeve, and the conductor track carrier 1 is designed as a spindle, and the conductor track 5 extends around the outer circumference.

[0061] The conductor track carrier 1 and the contact element carrier 3 can be designed such that a stop element determines a insertion depth of one carrier into the other.

[0062] The conductor carrier 1 preferably comprises at least one annular conductor track 5, wherein the at least one conductor track 5 is concave in cross-section in the direction of a common axis of rotation of the slip ring arrangement, so that the conductor track forms an annular groove 21.

[0063] Furthermore, in the illustrated embodiment, the conductor carrier 1 is designed as a spindle, on the outer circumference of which at least one concave conductor track 5 is arranged.

[0064] In the preferred embodiment shown in the figures, a ball bearing 6 is additionally provided between the conductor track carrier 1 and the contact element carrier 3. This ball bearing 6 is also not strictly necessary, since the ball elements 11 in the individual contact elements 7 already provide good support for the conductor track carrier 1, particularly if a sufficient number of contact elements 7 are present in a conductor track 5 and are distributed over the entire circumference of the conductor track 5.

[0065] The pluggable rotary connection of the invention is particularly advantageous when access to the rotary connection is restricted due to assembly requirements, as is often the case with construction machinery and similar equipment. According to the invention, it is then possible to simply pull the conductor carrier 1 out of the contact element carrier 3, clean or replace it, and reinsert it with a single movement, without requiring direct access to the contact element carrier 3.

[0066] An advantage of the invention is that commercially available contact pins, not intended for slip ring connections but designed as push-button or point contacts, can be used. These are simply mounted on a circuit board 13 in a known manner and connected to the connector via appropriate conductor tracks and flexible cables or conductor elements. The circuit board 13 with the contact pins 15 arranged on it is then mounted on a plastic contact element carrier 3, wherein guide holes are preferably formed in the side wall of the contact element carrier 3 corresponding to the contact pins 15, so that the contact pins 15 project into the interior of the contact element carrier 3.Particularly high manufacturing precision is not required, since the ball elements 11 in the contact pins 15 prevent excessive axial forces from being exerted on the contact pins 15 in the direction of the axis of rotation when the conductor carrier 1 is inserted into the contact element carrier 3. This allows for the creation of a pluggable rotary connection in which the two pluggable elements can be repeatedly connected and disconnected.

[0067] The invention also offers the advantage that it is possible to replace only one of the two elements, conductor carrier 1 or contact element carrier 3, in case of wear, which saves costs and reduces waste. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 5,575,664

[0003] CN 115548812A

[0005]

Claims

[1] Slip ring assembly with: a conductor track carrier (1) and a contact element carrier (3) which are rotatably held relative to each other about a common axis, wherein the conductor carrier (1) has at least one annular conductor track (5) arranged around the common axis, wherein the contact element carrier (3) has at least one contact element (7), wherein the contact element (7) comprises an elastic element (9) and a spherical element (11), wherein the spherical element (11) is elastically pressed against the conductor track (5) by the elastic element (9) in a direction substantially perpendicular to the common axis, is in contact with it during operation and rolls along the conductor track (5); the contact element (7) further comprises: a circuit board (13) with at least one contact pin (15) attached to it, wherein the contact pin (15) has an electrically conductive sheath (17) in which the elastic element (9) and the spherical element (11) are held. [2] Slip ring arrangement according to claim 1, wherein the conductor carrier (1) and the contact element carrier (3) are pluggable into each other in the direction of the common axis, wherein when one carrier (1, 3) is plugged into the other (3, 1) the ball element (11) rotates about an axis substantially perpendicular to the common axis. [3] Slip ring arrangement according to claim 1 or 2, wherein several conductor tracks (5) and / or several contact elements (7) are provided. [4] Slip ring arrangement according to one of the preceding claims, wherein the contact element carrier (3) is designed such that a plurality of contact elements (7) contact a conductor track (5), wherein the plurality of contact elements (7) is arranged to guide the two carriers (1, 3) relative to each other when inserted. [5] Slip ring arrangement according to one of the preceding claims, wherein the conductor track carrier (1) is designed in the form of a sleeve, the conductor track (5) extends around the inner circumference and the contact element carrier (3) is designed as a spindle. [6] Slip ring arrangement according to one of the preceding claims, wherein the contact element carrier (3) is designed in the form of a sleeve, the conductor track carrier (1) is designed as a spindle and the conductor track (5) extends around its outer circumference. [7] Contact element carrier (3) for a slip ring arrangement according to claim 6, with a circuit board (13) and at least one contact pin (15) attached to the circuit board (13); wherein the contact pin (15) has: an electrically conductive shell (17), an elastic element (9) and a spherical element (11), wherein the spherical element (11) is held in the shell (17) by the elastic element (9); wherein the contact pin (15) is arranged such that the elastic element (9) clamps the spherical element (11) in a direction substantially perpendicular to a longitudinal axis of the sleeve. [8] Contact element carrier (3) according to claim 7, wherein in operation an electrical connection is made via the spherical element (11) and the shell (17), without current flow through the elastic element (9). [9] Contact element carrier (3) for a slip ring arrangement according to claim 7 or 8, wherein the contact element carrier (3) is designed to define a receiving space into which a spindle-shaped conductor carrier (1) for contacting the contact elements (7) can be pluggably received.

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