ELECTRICAL CONTACT ARRANGEMENT

Description

[0001] The invention relates to an electrical contact arrangement comprising at least one contact pair formed by a primary and a secondary contact ring which are rotatable relative to one another about a longitudinal central axis and each have a conical contact surface surrounding the longitudinal central axis, wherein the secondary contact ring is arranged on a rotor which is rotatably mounted relative to a housing, at least one roller rolling between the primary and secondary contact rings of a respective contact pair, which is rotatably mounted about an axis of rotation perpendicular to the longitudinal central axis, wherein the roller has a conical contact surface surrounding the axis of rotation, which forms a line contact with the contact surfaces of the primary and secondary contact rings along a respective contact line, and at least one spring element,by which the contact surface of the roller is pressed against the contact surfaces of the primary and secondary contact rings, wherein the spring force of the at least one spring element acts parallel to the longitudinal central axis.

[0002] Electrical contact arrangements for transmitting electrical energy or electrical signals to rotating parts are known in various designs. For example, such electrical contact arrangements are used in processing machines, particularly multi-axis ones, e.g., for operating electrically operated clamping devices. If the contact arrangement is used to transmit electrical energy, high currents, for example, in the range of over 50 A, may be required, depending on the application. Depending on the application, this may involve direct current or alternating current. Also depending on the application, the speeds involved may be high, and power transmission at standstill may also be required.

[0003] In a common application, fluid transmission is also required in addition to electrical contact. Therefore, a rotary union is required in addition to the electrical contact arrangement.

[0004] It is also common that, on the one hand, electrical energy, for example as drive energy for an electrical unit, and, on the other hand, electrical signals, for example to control an electrical unit, have to be transmitted.

[0005] Carbon brush systems are known for transmitting direct current to rotating parts, but these have disadvantages, among other things, regarding maintenance costs and energy transmission when the machine is at a standstill.

[0006] Furthermore, contactless transmitters are known that can only transmit low power and only alternating current.

[0007] Also known are so-called gold wire systems. In these, a fixed contact finger presses against a circular surface. The achievable speeds are low and wear is high.

[0008] Electrical contact arrangements are also known in which current is transmitted via rolling elements rolling between contact surfaces. One of the exemplary embodiments shown in WO 2016 / 032336 A1, for example, shows a contact arrangement in which contact rollers are pressed against opposing contact rings, one of which is stationary and the other rotates about a longitudinal central axis. The contact rollers are rotatably mounted about axes of rotation perpendicular to the longitudinal central axis. The contact rings have conical contact surfaces, and the rollers have contact surfaces in the contact area that are curved like a spherical surface when viewed in longitudinal central section. The contact surfaces of the rollers are pressed against the opposing contact surfaces of the contact rings by means of springs that act in the axial direction of the axes of rotation.The contacts formed are essentially point contacts and the contact force is speed-dependent due to the centrifugal force acting on the rollers.

[0009] An electrical contact arrangement in which balls are arranged as rolling elements between bearing shells is disclosed in DE 31 50 427 A1. This contact arrangement is not suitable for high speeds, and the use of balls as rolling elements only provides a Hertzian point contact surface for low currents.

[0010] In the contact arrangement known from DE 192 16 855 B4, contact rollers are arranged between an inner conductor and a coaxially arranged outer conductor. These rollers have spirally projecting, outwardly extending, resilient contact blades. These are highly susceptible to wear and are not particularly advantageous in terms of contacting. Other contact arrangements with rolling elements are disclosed, for example, in DE 32 14 083 C2, WO 98 / 05104 A1, and DE 19 41 309 A.

[0011] A contact arrangement of the type mentioned above is disclosed in WO 02 / 01682 A1. The roller rolling between the primary and secondary contact rings of the contact pass has a conical contact surface surrounding the rotation axis. This contact surface forms a line contact with the contact surfaces of the primary and secondary contact rings, each running along a respective contact line. The contact surfaces of the primary and secondary contact rings are pressed against the contact surface of at least one roller by spring force. However, manufacturing must be carried out with very high precision to ensure that line contacts are actually formed. In practice, the formation of such line contacts can be disrupted by manufacturing tolerances and / or wear during operation.

[0012] The object of the invention is to provide an advantageous electrical contact arrangement of the type mentioned above, which can also be used for relatively high currents and is preferably suitable for both low and high speeds as well as for power transmission at standstill. According to the invention, this is achieved by a contact arrangement having the features of claim 1.

[0013] In the contact arrangement according to the invention, a support section of the secondary contact ring rests against a rotor base part of the rotor, and a contact section of the secondary contact ring, which has the contact surface, adjoins the support section radially on the outside. A support section of the primary contact ring rests against a pressure plate which is acted upon by at least one spring element and is mounted axially displaceably relative to a housing part of the electrical contact arrangement. A contact section of the primary contact ring, which has the contact surface, adjoins the support section radially on the outside. The angle measured on the side of the contact surface between the contact section and the support section of the respective primary and secondary contact ring is greater in the assembled state than in the unloaded state.The inclinations of the contact sections therefore correspond, in the assembled state, to the inclination of the contact surface of the respective roller with which they interact.

[0014] The design according to the invention ensures reliable contact and enables the transmission of high currents.

[0015] The contact surface of the at least one roller is preferably preloaded against the contact surfaces of the primary and secondary contact rings by at least one spring element acting on one of the contact rings, with the spring force acting parallel to the longitudinal center axis. This makes it possible to ensure that the contact pressure is at least substantially independent of the rotational speed. The contact arrangement according to the invention is thus also suitable for high rotational speeds.

[0016] A contact arrangement according to the invention is also advantageously suitable for power transmission at a standstill.

[0017] The contact lines formed by the contact surface of the roller or a respective one of the rollers with the contact surfaces of the primary and secondary contact rings advantageously lie on straight lines that intersect on the longitudinal center axis of the contact arrangement, forming a common intersection point with the axis of rotation about which the respective roller is rotatably mounted. As a result, when the primary and secondary contact rings rotate relative to each other, the roller rolls on the contact surfaces of the primary and secondary contact rings across the entire width of the formed line contacts, at least essentially without slippage.

[0018] In a preferred embodiment of the invention, at least three rollers are provided, arranged around the longitudinal center axis, preferably evenly spaced, and mounted for rotation about axes of rotation perpendicular to the longitudinal center axis. These rollers have conical contact surfaces and roll between the primary and secondary contact rings. This makes it possible to achieve a roller support ring, of which the rollers are mounted for rotation about the respective axis of rotation, coaxially aligned with the longitudinal center axis of the contact arrangement solely by the rollers rolling on the primary and secondary contact rings. Additional mounting of the roller support ring around the longitudinal center axis is thus unnecessary.

[0019] An electrical contact arrangement according to the invention can additionally comprise a ball contact unit for transmitting electrical signals (low current). This can advantageously comprise at least one contact disc with a plurality of annular conductor tracks, at least one set of a plurality of coaxially arranged annular mating contacts whose diameters correspond to the diameters of the annular conductor tracks, at least one ball guide disc arranged between the at least one contact disc and the mating contacts interacting with the contact disc, and contact balls guided by the ball guide disc, which roll between a respective one of the conductor tracks and the annular mating contact belonging to this conductor track.Preferably, at least one spring element cooperates with each of the annular counter-contacts, which spring element presses the annular counter-contact against the balls rolling between this counter-contact and the associated conductor track.

[0020] An electrical contact arrangement according to the invention can be combined with a rotary feedthrough for fluids.

[0021] A contact arrangement according to the invention can be advantageously used to transmit electrical energy to a rotating electrical unit, in particular to an electric drive that rotates with a rotating part, for example, a clamping device of a particularly multi-axis processing machine. A contact arrangement according to the invention is also suitable for transmitting electrical energy from a rotating part, for example, a rotor of a generator, to a stationary part.

[0022] By means of a contact arrangement according to the invention, relatively high currents can be transmitted, which can be, for example, more than 50 A or, depending on the application, even more than 200 A.

[0023] Unless otherwise stated in this document, reference to the "axial direction" refers to the longitudinal center axis of the contact arrangement.

[0024] Further advantages and details of the invention are explained below with reference to the accompanying drawings, in which: Fig. 1 is an oblique view of an embodiment of an electrical contact arrangement according to the invention in combination with a rotary feedthrough for a fluid; Fig. 2 is a longitudinal central section; Fig. 3 is an exploded view of the conical contact unit, with the rotor not shown exploded; Fig. 4 is an exploded view of the rotor of the conical contact unit; Fig. 5 is an exploded view of the ball contact unit, with the rotor of the ball contact unit not shown exploded. Fig. 6 is an exploded view of the rotor of the ball contact unit.

[0025] An embodiment of a contact arrangement according to the invention is described below with reference to Fig. 1 to 6described. In this exemplary embodiment, the contact arrangement 1 according to the invention is combined with a rotary feedthrough 2 for a fluid. The rotary feedthrough 2 has, in a known manner, a housing part 3 which essentially has the shape of a hollow cylinder. Axially spaced channels 4 for the passage of a fluid, for example air or water, run radially through the housing part 3. The channels 4 originate from the outer circumferential surface and open into an annular groove 5 running around the inner circumferential surface. A rotating part 6 is rotatably mounted in the housing part 3, here by means of ball bearings 7, 8. The rotating part 6 has axially extending channels 9 for the passage of the fluid, which open at an axial end of the rotating part 6. Each channel 9 is connected to one of the annular grooves 5 via a respective bore 10.

[0026] The rotating part 6 is designed as a hollow cylinder. Electrical lines of the electrical contact arrangement 1, described in more detail below, pass through the interior of the rotating part 6.

[0027] However, an electrical contact arrangement according to the invention could also be designed without a rotary feedthrough 2, ie the rotary feedthrough 2 could be omitted.

[0028] In the exemplary embodiment, the electrical contact arrangement 1 comprises a conical contact unit 1a and a ball contact unit 1b. The ball contact unit 1b could also be omitted, so that the electrical contact arrangement 1 would be formed solely by the conical contact unit 1a.

[0029] The conical contact unit 1a comprises two contact pairs, each formed by a primary contact ring 11 and a secondary contact ring 12. The primary contact rings 11 are held non-rotatably relative to a housing, which in the exemplary embodiment is formed by the two housing parts 13, 14.

[0030] The secondary contact rings 12 are arranged on a rotor 15 which is rotatably mounted relative to the housing formed by the housing parts 13, 14, specifically about the longitudinal central axis 16 of the contact arrangement.

[0031] If the contact arrangement is combined with a rotary feedthrough for a fluid, the rotating part 6 is also mounted for rotation about the longitudinal center axis 16, and the rotating part 6 is connected in a rotationally fixed manner to the rotor 15. For example, a rotor housing part 17 can have prongs 17a and recesses located therebetween, which engage in corresponding recesses and prongs of the rotating part 6.

[0032] In the exemplary embodiment, the rotor 15 comprises the rotor housing parts 17, 18 and the rotor base part 19. The secondary contact rings 12 are positioned and held by these parts.

[0033] The rotor housing parts 17, 18 can be connected to the rotor base part 19, for example, via a snap connection, as shown. For this purpose, locking arms 17b, 18b, which have locking lugs, can be arranged on the rotor housing parts 17, 18, which engage with locking recesses in the rotor base part 19. A screw connection, for example, would also be possible.

[0034] A different design of the rotor 15 with more or fewer parts is conceivable and possible.

[0035] For the rotatable mounting of the rotor 15 relative to the housing parts 13, 14, inner rings of ball bearings 20, 21 are arranged on the rotor housing parts 17, 18, the outer rings of which are held in seats 13a, 14a of the housing parts 13, 14.

[0036] The secondary contact rings 12 each have an annular support section 12a, which lies in a plane perpendicular to the longitudinal central axis 16, and a radially outwardly adjoining annular contact section 12b. Contacting tabs 12c protrude from the support section 12a, in particular in the axial direction of the longitudinal central axis 16, to which electrical conductors 22a of cables 22 are connected, for example, soldered. In the exemplary embodiment, each secondary contact ring 12 has two contacting tabs 12c, although, for example, only one contacting tab 12c with a connected electrical conductor 22a could be present per secondary contact ring 12. The contacting tabs 12c could also be omitted, and at least one electrical conductor could be attached directly to the support section 12a of the respective secondary contact ring 12.

[0037] The support sections 12a rest on the rotor base part 19. In the exemplary embodiment, they are clamped between the respective rotor housing part 17, 18 and the rotor base part 19. Other types of fastening the secondary contact rings 12 to a rotor base part and / or rotor housing part are conceivable and possible.

[0038] The contact sections 12b of the secondary contact rings 12 are angularly aligned with the respective support section 12a. The surface of the respective contact section 12b that interacts with the rollers 27 forms a contact surface 12d. This has the shape of a conical surface.

[0039] The contact sections 12b of the secondary contact rings 12 are free in the assembled state. Thus, the contact sections 12b of the secondary contact rings 12 are bendable relative to the respective support section 12a, i.e., the angular positions of the contact sections 12b are variable relative to the angular positions of the support sections 12a.

[0040] The primary contact rings 11 each have an annular support section 11a, which lies in a plane perpendicular to the longitudinal central axis 16. Radially outwardly, a contact section 11b adjoins the support section 11a, which is arranged at an angle to the support section 11a. The side of the respective primary contact ring 11 that interacts with the roller 27 forms a contact surface 11d. This contact surface has the shape of a conical surface.

[0041] In the exemplary embodiment, two contacting tabs 11c protrude from the support sections 11a, in particular axially, and are connected to electrical conductors 23a of cables 23, for example by soldering. Only one contacting tab 11c could be provided per primary contact ring 11, or at least one conductor could be connected directly to the respective support section 11a. Through the connection to the electrical conductors 23a, the primary contact rings 11 in the exemplary embodiment are also secured against rotation about the longitudinal central axis 16. Such an anti-twist device could also be designed in a different way instead or additionally.

[0042] The support sections 11a of the primary contact rings 11 each rest on a pressure plate 24, 25. The pressure plates 24, 25 are held axially displaceable but non-rotatable relative to the housing parts 13, 14, for example, by ribs of the housing parts 13, 14 projecting into slots 24a, 25a of the pressure plates. Spring elements 26 are arranged between the pressure plates 24, 25 and the respective associated housing part 13, 14. In the exemplary embodiment, these are designed in the form of helical springs, with several spring elements 26 arranged around the longitudinal center axis 16. For example, at least one annular leaf spring could also be used as the spring element instead.

[0043] The contact sections 11b of the primary contact rings 11 are free in the assembled state. Thus, the contact sections 11b of the primary contact rings 11 are bendable relative to the respective support section 11a, i.e., the angular positions of the contact sections 11b are variable relative to the angular positions of the support sections 11a.

[0044] Rollers 27 run between the primary and secondary contact rings 11, 12 of each contact pair. The rollers 27 are mounted for rotation about axes of rotation 28, which are perpendicular to the longitudinal center axis 16. Several rollers 27 are provided per contact pair, which are distributed around the longitudinal center axis 16, preferably at equal angular intervals. The axes of rotation 28 of the rollers 27 are thus at an angle to one another, with the angles between successive axes of rotation 28 preferably being equal.

[0045] The rollers 27 consist of an electrically conductive material, at least in the area of ​​the running surfaces.

[0046] A roller support ring 29 is used for rotatably supporting each of the rollers 27. In the exemplary embodiment, this ring has radially inwardly projecting axle journals 29a, on each of which a roller 27 is rotatably mounted, preferably by means of a ball bearing 30.

[0047] Each roller 27 is designed in the shape of a truncated cone of a hollow cone. The running surface of the roller forms a contact surface 27a, which has the shape of a conical surface.

[0048] In the assembled state, the contact surfaces 11d, 12d of the primary and secondary contact rings rest against this contact surface 27a over the entire axial extent of the contact surface 27a of a respective roller 27, relative to the axis of rotation 28. A line contact is thus formed between the contact surface of a respective roller 27 and the contact surfaces 11d, 12d of the associated primary and secondary contact rings 11, 12. The contact thus occurs along a contact line 31, 32, which represents the line of contact between the respective contact surface 11d, 12d of the primary or secondary contact ring 11, 12 and the contact surface 27a of the respective roller 27. This contact line 31, 32 is visible in the longitudinal center section through the contact arrangement that passes through the axis of rotation 28 of the respective roller 27, cf. Fig. 2 .

[0049] Each of the rollers 27 thus forms a primary contact line 31 with the associated primary contact ring 11 and a secondary contact line 32 with the associated secondary contact ring 12. The primary and secondary contact lines between a respective roller 27 and the associated primary and secondary contact rings 11, 12 lie on straight lines which are at an angle to one another and whose intersection point lies on the longitudinal center axis 16, cf. Fig. 2 The intersection point of these two straight lines also lies on the rotational axis 28 of this roller 27. These two straight lines, the longitudinal center axis 16 and the rotational axis 28, thus have a common intersection point. The angle 33 formed by these two straight lines is approximately 35° in the exemplary embodiment. This angle 33 is preferably in the range of 25° to 45°, particularly preferably in the range of 30° to 40°.

[0050] The primary and secondary contact rings 11, 12 and the rollers 27 are pressed together by the spring elements 26. The spring elements 26 act on the primary contact rings 11 via the pressure plates 24, 25 in the axial direction (relative to the longitudinal center axis 16).

[0051] In principle, spring elements could also be arranged on only one side. Thus, one of the pressure plates 24, 25 could be omitted, and the respective primary contact ring 11 could rest directly against the respective housing part 13, 14 with its supporting section 11a.

[0052] Due to the spring force of the spring elements 26, the angle 48 between the support sections 11a, 12a and contact sections 11b, 12b of the contact rings 11, 12 is slightly increased in the assembled state compared to the unloaded state of the contact rings 11, 12. This angle 48 is measured on the side of the respective contact ring 11, 12 on which the contact surface 11d, 12d is located. This increase in the angle 48 is preferably less than 5°. A value of more than 0.5° is preferred. As a result, the inclination of the contact sections 11b, 12b in the assembled state exactly matches the inclination of the contact surface 27a of the respective roller 27.

[0053] The thickness of the sheet metal from which the contact rings 11, 12 are formed is also selected according to the current strength for which the contact arrangement is designed. Advantageously, the sheet metal thickness is in the range of 0.5 mm to 2 mm. For example, the sheet metal thickness is in the range of 0.5 mm to 1 mm for currents of up to 100 amperes and in the range of 1 mm to 2 mm for currents of up to 1000 amperes.

[0054] To interact with each contact pair, preferably at least three rollers 27 distributed around the circumference are provided. For space reasons, three rollers are preferred, and more than four rollers are less preferred. The roller support ring 29 is thus self-centering due to the interaction of the rollers 27 with the primary and secondary contact rings 11, 12. Additional support for the roller support ring is not required.

[0055] The cables 23, which rotate with the rotor 15 and are connected to the secondary contact rings 12, are led out axially (relative to the longitudinal center axis 16) through an opening 13b in the housing part 13. If the electrical contact arrangement is combined with a rotary feedthrough 2, as shown in the exemplary embodiment, the cables 23 can be led through the central opening of the rotating part 6.

[0056] In the exemplary embodiment, the cables 22 connected to the primary contact rings 11 are led out through edge-side grooves 14b in the housing part 14.

[0057] When the rotor 15 is rotated relative to the housing formed by the housing parts 13, 14, for example by driving the rotating part 6 of the rotary union 2, the roller support rings 29 rotate at half speed.

[0058] The housing parts 13, 14 are connected to each other by axially aligned screws (not shown). The housing of the conical contact unit 1a could also have additional or differently designed housing parts.

[0059] In the exemplary embodiment shown, the electrical contact arrangement is of two-pole design, i.e. there are two contact pairs each consisting of a primary and a secondary contact ring, between which at least one roller rolls, wherein the secondary contact rings are arranged on a common rotor. A contact arrangement according to the invention could also have only one pole or more than two poles. In a design with only one pole, the rotor 15 would therefore only have one secondary contact ring 12. For example, the contact arrangement according to the invention for transmitting alternating current (three phases and a neutral conductor) could be of four-pole design. The conical contact unit 1a shown in the exemplary embodiment could, for example, be doubled for this purpose.

[0060] In the illustrated embodiment, the contact arrangement according to the invention further comprises a ball contact unit 1b. This serves in particular for the transmission of electrical signals (data). The currents to be transmitted are thus relatively low, preferably less than 1 A.

[0061] The ball contact unit has a rotor 34, which is rotatably mounted about the longitudinal center arm 16 and, in the exemplary embodiment, has two contact disks 35. The contact disks 35 are arranged on interconnected rotor parts 36, 37, which together form a base body of the rotor 34. Such a base body could also have more than two parts or be formed as a single piece. The rotor base body is rotatably mounted relative to a housing of the ball contact arrangement. In the exemplary embodiment, this is formed by the housing parts 38, 39. The housing parts 38, 39 can be connected by screws. Such a housing could also have more than two parts or be of a different design. For the rotatable mounting of the rotor 34 relative to the housing, ball bearings 40, 41 are provided in the exemplary embodiment, with their inner rings arranged on the rotor parts 36, 37. The outer rings of the ball bearings are held in seats 38a, 39a of the housing parts 38, 39.

[0062] The contact disks 35 each have a plurality of annular conductor tracks 35a coaxial with the longitudinal center axis 16. The conductor tracks are arranged on the sides of the contact disks 35 facing away from each other.

[0063] Furthermore, the ball contact unit 1b has a set of mating contacts 42 for each of the contact disks 35. Each set of mating contacts 42 is formed by several annular mating contacts 42 arranged coaxially to the longitudinal center axis 16 and having different diameters. The diameters of the mating contacts 42 of each set correspond to the diameters of the conductor tracks 35a of the associated contact disk 35.

[0064] The mating contacts 42 extend, on their sides remote from the contact disks, into annular grooves 38b, 39b of the housing parts 38, 39. Spring elements 43, which in the exemplary embodiment are in the form of helical springs, are arranged between the mating contacts 42 and the bottoms of the grooves 38b, 39b. For each of the mating contacts 42, there are several helical springs distributed around the circumference of the longitudinal central axis 16—four in the exemplary embodiment.

[0065] Electrical conductors 44a of cables 44 are connected to the mating contacts 42, for example by soldering. Electrical conductors of cables 45 are connected to the conductor tracks 35a of the contact disk 35.

[0066] Between a respective conductor track 35a of a respective contact disk 35 and the associated annular mating contact 42, a plurality of contact balls 46 distributed around the circumference of the longitudinal center axis 16 roll. These contact balls 46 are arranged in openings of a respective ball guide disk. A ball guide disk 47 with the contact balls 46 guided by it is provided between each respective contact disk 35 and the associated annular mating contacts 42.

[0067] The contact balls 46 consist entirely of an electrically conductive material or are coated with such a material.

[0068] In the exemplary embodiment, each conductor track 35a and the associated mating contact 42 are assigned three contact balls 46, which are arranged at equal intervals, i.e., offset by 120°, around the longitudinal center axis 16. At least three contact balls are preferred; more than three contact balls are conceivable and possible.

[0069] In order to increase the distances between the contact balls 46 assigned to adjacent conductor tracks 35a and adjacent mating contacts 42, these contact balls are preferably arranged offset from one another with respect to their angular position about the longitudinal central axis 16.

[0070] The ball guide disc 47 thus represents a type of ball cage for the contact balls 46. Preferably, the contact balls 46 are held in the openings of the ball guide disc 47 in such a way that the contact balls 46 cannot fall out during assembly.

[0071] The spring elements 43 thus press the mating contacts 42 against the contact balls 46 and the contact balls 46 are thus pressed against the conductor tracks 35a of the contact disks 35.

[0072] Due to the individually spring-loaded mating contacts 42, size tolerances of the contact balls 46 can be accommodated, in particular in combination with the fact that three contact balls 46 are provided per conductor track 35a or mating contact 42.

[0073] The mating contacts 42 are secured against rotation about the longitudinal center axis 16 by their connection to the electrical conductors 44a of the cables 44. Additional anti-twist protection could also be achieved by further measures.

[0074] The cables 45, whose electrical conductors are connected to the conductor tracks 35a of the contact discs 35, are preferably led out axially through openings in the ball guide disc 47 and in the housing part 38. These cables 45 could also be led out through the central axial opening of the conical contact unit 1a. Alternatively, the cables 45 could also be led out on the opposite side of the ball contact unit 1b through the openings in the other ball guide disc 47 and the other housing part 39.

[0075] In principle, it would also be conceivable and possible that only one of the two sets of counter contacts 42 is assigned spring elements 43, by means of which the contact balls 46 arranged in the two ball guide discs 47 are pressed against the conductor tracks 35 and opposite counter contacts 42.

[0076] Instead of coil springs, other spring elements could also be provided, for example at least one annular leaf spring could be present per counter contact 42.

[0077] The rotor 34 of the ball contact unit 1b could also have only a single contact disc 35 with associated mating contacts 42, with only a single ball guide disc 47 with contact balls 46 being present. On the other hand, more than two contact discs 35 could be present; for example, the illustrated ball contact unit 1b could be present twice.

[0078] The rotors 15 and 34 of the conical contact unit 1a and the ball contact unit 1b are connected to each other in a rotationally locked manner. For example, the rotor housing part 18 of the rotor 15 has prongs 18a with recesses therebetween, and the rotor part 36 of the rotor 34 has prongs 36a with recesses therebetween. The prongs 18a, 35a of one part engage the recesses of the other part.

[0079] In principle, a kinematic reversal would also be conceivable and possible in the sense that the rotor 15 of the conical contact unit and, if present, the rotor 34 of the ball contact unit are arranged in a rotationally fixed manner with respect to the longitudinal central axis 16 and the housing of the conical contact unit 1a and, if present, the housing of the ball contact unit 1b rotates about the longitudinal central axis 16. Legend to the reference numbers 1 Contact arrangement 17 Rotor housing part 1a Cone contact unit 17a prong 1b ball contact unit 17b locking arm 2 rotary union 18 Rotor housing part 3 Housing part 18a prong 4 channel 18b locking arm 5 Ring groove 19 Rotor base part 6 Turned part 20 ball bearings 7 ball bearings 21 ball bearings 8 ball bearings 22 Cable 9 channel 22a electrical conductor 10 drilling 23 Cable 11 primary contact ring 23a electrical conductor 11a supporting section 24 printing plate 11b Contact section 24a slot 11c Contact tab 25 printing plate 11d Contact surface 25a slot 12 secondary contact ring 26 spring element 12a supporting section 27 roller 12b Contact section 27a Contact surface 12c Contact tab 28 axis of rotation 12d Contact surface 29 Roller support ring 13 Housing part 29a axle journal 13a seat 30 ball bearings 13b opening 31 Contact line 14 Housing part 32 Contact line 14a seat 33 angle 14b Nut 34 rotor 15 rotor 35 Contact disc 16 Longitudinal center axis 35a conductor track 36 Rotor part 36a prong 37 Rotor part 38 Housing part 38a seat 38b Nut 39 Housing part 39a seat 39b Nut 40 ball bearings 41 ball bearings 42 Counter contact 43 spring element 44 Cable 44a electrical conductor 45 Cable 46 Contact ball 47 Ball guide disc 48 angle

Claims

1. Electrical contact arrangement comprising - a housing, - a rotor (15) which is mounted rotatably with respect to a housing, - at least one pair of contacts formed by a primary and a secondary contact ring (11, 12), which can be rotated with respect to one another about a longitudinal center axis (16) and each of which has a contact surface (11d, 12d) which is in the form of a cone envelope and surrounds the longitudinal center axis (16), wherein the secondary contact ring (12) is arranged on the rotor (15), - at least one roller (27), which rolls between the primary and the secondary contact ring (11, 12) of a respective pair of contacts and is mounted rotatably about an axis of rotation (28) at right angles to the longitudinal center axis (16), wherein the roller (27) has a contact surface (27a) which is in the form of a cone envelope, surrounds the axis of rotation (28), and forms a respective line contact, running along a respective contact line (31, 32), with the contact surfaces (11d, 12d) of the primary and secondary contact rings (11, 12), and - at least one spring element (26), which presses the contact surface (27a) of the roller (27) against the contact surfaces (11d, 12d) of the primary and secondary contact rings (11, 12), wherein the spring force of the at least one spring element (26) acts parallel to the longitudinal center axis (16), characterized in that a support portion (12a) of the secondary contact ring (12) rests on a rotor base part (19) of the rotor (15) and a contact portion (12b) of the secondary contact ring (12), which contact portion comprises the contact surface (12d), adjoins the support portion (12a) radially to the outside, and a support portion (11a) of the primary contact ring (11) rests on a pressure plate (24, 25) of the electrical contact arrangement, which is acted upon by at least one spring element (26) and is mounted axially displaceably with respect to a housing part (13, 14) of the housing of the electrical contact arrangement, wherein a contact portion (11b) of the primary contact ring (11) adjoins the support portion (11a) radially to the outside and comprises the contact surface (11d), wherein the angle (48), measured on the side of the contact surface (11d, 12d), between the contact portion (11b, 12b) and the support portion (11a, 12a) of the respective primary and secondary contact ring (11, 12) is greater in the assembled state than in the unloaded state, and the inclination of the respective contact portion (11b, 12b) in the assembled state matches the inclination of the contact surface (27a) of the respective roller (27) with which it interacts.

2. Electrical contact arrangement in accordance with Claim 1 characterized in that the axis of rotation (28) of the at least one roller (27) and the straight lines on which lie the contact lines (31, 32) forming the contact surface (27a) of this roller (27) with the contact surface (11d, 12d) of the primary and the secondary contact ring (11, 12) have a common intersection point which lies on the longitudinal center axis (16).

3. Electrical contact arrangement in accordance with Claim 1 or 2, characterized in that at least three rollers (27), which are spaced apart around the longitudinal center axis (16), are mounted rotatably about respective axes of rotation (28) at right angles to the longitudinal center axis (16), and have contact surfaces (27a) in the form of a cone envelope, roll between the primary and the secondary contact ring (11, 12) of a respective pair of contacts.

4. Electrical contact arrangement in accordance with Claim 3, characterized in that three rollers (27), which are spaced apart around the longitudinal center axis (16) by 120° in each case, roll between the primary and the secondary contact ring (11, 12) of a respective pair of contacts.

5. Electrical contact arrangement in accordance with Claim 3 or 4, characterized in that the rollers (27) are mounted rotatably about the respective axis of rotation (28) on a roller support ring (29), wherein the roller support ring (29) is centered in relation to the longitudinal center axis (16) by the interaction of the rollers (27) with the contact surfaces (11d, 12d) of the primary and the secondary contact ring (11, 12).

6. Electrical contact arrangement in accordance with any one of Claims 1 to 5, characterized in that the contact arrangement has first and second pairs of contacts, which are each formed by a primary and a secondary contact ring (11, 12), wherein the rotor (15) comprises the secondary contact rings (12) of the first and the second pair of contacts and the primary contact rings (11) are rotationally conjointly connected to housing parts (13, 14) arranged on opposite sides of the rotor (15).

7. Electrical contact arrangement in accordance with any one of Claims 1 to 6, characterized in that the angle (48), measured on the side of the contact surface (11d, 12d), between the contact portion (11b, 12b) and the support portion (11a, 12a) of the respective primary and secondary contact ring (11, 12) is more than 0.5° greater in the assembled state than in the unloaded state.

8. Electrical contact arrangement in accordance with any one of Claims 1 to 7, characterized in that the angle (48), measured on the side of the contact surface (11d, 12d), between the contact portion (11b, 12b) and the support portion (11a, 12a) of the respective primary and secondary contact ring (11, 12) is less than 5° greater in the assembled state than in the unloaded state.

9. Electrical contact arrangement in accordance with any one of Claims 1 to 8, characterized in that the contact portions (11b, 12b) of the primary and secondary contact rings (11, 12) in the assembled state are aligned at an angle in relation to the respective support portion (11a, 12a) from which they extend.

10. Electrical contact arrangement in accordance with any one of Claims 1 to 9, characterized in that, for the purpose of transmitting electrical signals, the contact arrangement has a ball contact unit (1b), comprising - at least one contact disk (35) with a plurality of annular conductor tracks (35a) coaxial with the longitudinal center axis (16), - at least one set of a plurality of mating contacts (42) which are concentric in relation to the longitudinal center axis (16) and the diameters of which correspond to the diameters of the annular conductor tracks (35a) of the contact disk (35), - at least one ball guiding disk (47), which is arranged between the at least one contact disk (35) and the mating contacts (42) interacting with the contact disk (35), and - contact balls (46), which are guided by the ball guiding disk (47) and roll between a respective one of the conductor tracks (35a) and the annular mating contact (42) assigned to this conductor track (35a).

11. Electrical contact arrangement in accordance with Claim 10, characterized in that at least one spring element (43) interacts with each of the annular mating contacts (42) and presses the annular mating contact (42) against the contact balls (46) rolling between this mating contact (42) and the associated conductor track (35a).

12. Electrical contact arrangement in accordance with Claim 10 or 11, characterized in that, to axially displacably guide the mating contacts (42), the annular mating contacts (42) protrude into annular grooves (38b, 39b) in a housing part (38, 39) of the ball contact unit (1b).