ROTOR ARRANGEMENT FOR A SLIP RING ASSEMBLY AND ROTARY COUPLING ARRANGEMENT COMPRISING A ROTOR ARRANGEMENT OF THIS KIND

Abstract

A rotor arrangement for a slip ring assembly, comprising a shaft element and at least one contact ring. The shaft element is at least partially in the form of a hollow shaft with a hollow interior and a casing wall. The shaft element has a middle section and each contact ring is arranged on the shaft element in the middle section and is electrically insulated from the shaft element by means of an insulation. The middle section has at least one cutout through the insulation and the casing wall into the interior. Each contact ring is connected to a cable element which is guided through one of the at least one cutout into the interior. The shaft element has a first end section with an outer circumferential cross section for the rotationally fixed coupling. Furthermore, a rotary coupling arrangement comprising a rotor arrangement of this kind is proposed.

Claims

1. A rotor arrangement for a slip ring assembly, comprising a shaft element and at least one contact ring, wherein the shaft element is at least partially in the form of a hollow shaft with a hollow interior and a casing wall, wherein the shaft element has a middle section, wherein each contact ring is arranged on the shaft element in the middle section, wherein the middle section has at least one cutout through the casing wall into the interior, wherein each contact ring is connected to a cable element which is guided through one of the at least one cutout into the interior, and wherein the shaft element has a first end section with an outer circumferential cross section for the rotationally fixed coupling, wherein the middle section is offset in relation to the first end section by a flange, wherein the flange has an outside diameter which is larger than a smallest outside diameter of the first end section and larger than an outside diameter of the middle section, wherein a smallest outside diameter of the first end section is larger than an outside diameter of the middle section, wherein the outer circumferential cross section of the first end section is in the form of a profile cross section, wherein the shaft element is of integral design, and wherein the rotor arrangement has more than one contact ring, and wherein an insulating ring which electrically insulates the adjacent contact rings from one another is arranged between two adjacent contact rings in each case.

2. A rotor arrangement for a slip ring assembly, comprising a shaft element and at least one contact ring, wherein the shaft element is at least partially in the form of a hollow shaft with a hollow interior and a casing wall, wherein the shaft element has a middle section, wherein each contact ring is arranged on the shaft element in the middle section, wherein the middle section has at least one cutout through the casing wall into the interior, wherein each contact ring is connected to a cable element which is guided through one of the at least one cutout into the interior, and wherein the shaft element has a first end section with an outer circumferential cross section for the rotationally fixed coupling.

3. The rotor arrangement as claimed in claim 2, wherein the middle section is offset in relation to the first end section by a flange, wherein the flange has an outside diameter which is larger than a smallest outside diameter of the first end section and larger than an outside diameter of the middle section.

4. The rotor arrangement as claimed in claim 2, wherein a smallest outside diameter of the first end section is larger than an outside diameter of the middle section.

5. The rotor arrangement as claimed in claim 2, wherein the outer circumferential cross section of the first end section is in the form of a profile cross section, wherein the first end section is of flattened design.

6. The rotor arrangement as claimed in claim 2, wherein the shaft element is of integral design.

7. The rotor arrangement as claimed in claim 2, wherein the shaft element is formed from a material which has a shear modulus of greater than 75 GPa.

8. The rotor arrangement as claimed in claim 2, wherein each contact ring is electrically insulated from the shaft element by means of an insulation, wherein the at least one cutout is formed through the insulation and the casing wall into the interior.

9. The rotor arrangement as claimed in claim 2, wherein the shaft element is formed from an electrically insulating material.

10. The rotor arrangement as claimed in claim 2, wherein the shaft element is formed from a material which has a shear modulus of greater than 100 GPa.

11. The rotor arrangement as claimed in claim 2, wherein the rotor arrangement has more than one contact ring, and wherein an insulating ring which electrically insulates the adjacent contact rings from one another is arranged between two adjacent contact rings in each case.

12. The rotor arrangement as claimed in claim 3, wherein an electrically insulating insulating ring is arranged on the middle section on the flange.

13. The rotor arrangement as claimed in claim 8, wherein the insulation is in the form of a sleeve which is composed of an electrically insulating material and which is arranged on the middle section of the shaft element.

14. The rotor arrangement as claimed in claim 8, wherein the insulation is in the form of an adhesive layer, wherein the adhesive layer is provided by means of an adhesive which is composed of an electrically insulating material.

15. The rotor arrangement as claimed in claim 2, wherein the shaft element has a second end section which is opposite the first end section and in which the casing wall is fully closed.

16. The rotor arrangement as claimed in 14, wherein each contact ring is adhesively bonded onto the middle section.

17. The rotor arrangement as claimed in claim 16, wherein respectively adjacent contact rings are arranged on the middle section in such a way that an air gap remains between them.

18. The rotor arrangement as claimed in claim 2, wherein each contact ring has a radial inner face, a radial outer face and two side faces, and wherein each contact ring is connected to a cable element by way of one of its side faces.

19. The rotor arrangement as claimed in claim 2, wherein the rotor arrangement has at least fourteen contact rings.

20. The rotor arrangement as claimed in claim 2, wherein the rotor arrangement has a number of cutouts which corresponds to the number of contact rings.

21. The rotor arrangement as claimed in claim 2, wherein the rotor arrangement has at least one first cutout and one second cutout, wherein the first cutout and the second cutout are formed in the middle section such that they are offset in relation to one another in the circumferential direction.

22. A rotary coupling arrangement for a coordinate measuring device, comprising a slip ring assembly comprising a rotor arrangement for a slip ring assembly, comprising a shaft element and at least one contact ring, wherein the shaft element is at least partially in the form of a hollow shaft with a hollow interior and a casing wall, wherein the shaft element has a middle section, wherein each contact ring is arranged on the shaft element in the middle section, wherein the middle section has at least one cutout through the casing wall into the interior, wherein each contact ring is connected to a cable element which is guided through one of the at least one cutout into the interior, and wherein the shaft element has a first end section with an outer circumferential cross section for the rotationally fixed coupling, wherein the shaft element has a second end section which is opposite the first end section and in which the casing wall is fully closed, and wherein the rotary coupling arrangement further comprises a rotatable coupling assembly which has a first end and a second end which is opposite the first end, wherein the first end has a coupling interface, and wherein the second end has a slip ring assembly interface for rotationally fixed coupling to the first end section of the rotor arrangement, and comprising a rotation position measuring system for ascertaining a rotation position of the rotor arrangement of the slip ring assembly, and wherein the second end section is arranged on or in the rotation position measuring system.

23. A rotary coupling arrangement for a coordinate measuring device, comprising a slip ring assembly comprising a rotor arrangement for a slip ring assembly, comprising a shaft element and at least one contact ring, wherein the shaft element is at least partially in the form of a hollow shaft with a hollow interior and a casing wall, wherein the shaft element has a middle section, wherein each contact ring is arranged on the shaft element in the middle section, wherein the middle section has at least one cutout through the casing wall into the interior, wherein each contact ring is connected to a cable element which is guided through one of the at least one cutout into the interior, and wherein the shaft element has a first end section with an outer circumferential cross section for the rotationally fixed coupling, the rotary coupling arrangement further comprising a rotatable coupling assembly which has a first end and a second end which is opposite the first end, wherein the first end has a coupling interface, and wherein the second end has a slip ring assembly interface for rotationally fixed coupling to the first end section of the rotor arrangement, and comprising a rotation position measuring system for ascertaining a rotation position of the rotor arrangement of the slip ring assembly.

24. The rotary coupling arrangement as claimed in claim 23, wherein the rotary coupling arrangement has a drive device which is coupled to the coupling assembly in order to rotate the coupling assembly.

25. The rotary coupling arrangement as claimed in claim 23, wherein the shaft element has a second end section which is opposite the first end section and in which the casing wall is fully closed, and wherein the second end section is arranged on or in the rotation position measuring system.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0070] Exemplary embodiments of the invention are shown in the drawing and will be explained in greater detail in the following description. In the figures:

[0071] FIG. 1 shows an embodiment of a rotary coupling arrangement,

[0072] FIG. 2a shows an embodiment of a rotor arrangement,

[0073] FIG. 2b shows a schematic cross-sectional view of a contact ring,

[0074] FIG. 3 shows a symmetrical view of an embodiment of a shaft element of a rotor arrangement, and

[0075] FIG. 4 shows an embodiment of a rotor arrangement.

DETAILED DESCRIPTION OF THE INVENTION

[0076] FIG. 1 shows an embodiment of a rotary coupling arrangement 10. A rotary coupling arrangement 10 of this kind can be used, in particular, in coordinate measuring devices. Said rotary coupling arrangement is used, for example, to couple a sensor to a support structure in a rotatable manner. In particular, it is possible to rotate freely through 360° several times, so-called n×360° rotatability. In this case, the dimensions of the rotary coupling arrangement can be freely selected. Furthermore, other applications are also feasible, for example in rotary tables or in other applications when rotation axes are intended to be freely pivoted through more than 360°. The use of the rotary coupling arrangement 10 in a coordinate measuring device, where it serves for coupling to a sensor, will be described in the text which follows.

[0077] To this end, the rotary coupling arrangement 10 has a sensor interface 12. A sensor can be arranged on the sensor interface 12, said sensor then being freely rotatable about a rotation axis 14. In the illustrated embodiment, the rotary coupling arrangement has to ensure in this case that a rotary movement at a sensor-side end, which rotary movement is identified by an arrow 16, is identical to a rotary movement at an opposite end, which rotary movement at the opposite end is identified by an arrow 18. Rotary movements 16 and 18 would have to be free of hysteresis and identical in order to be able to detect a rotation position of a sensor at the sensor interface 12 without hysteresis by means of a rotation position measuring system 20.

[0078] In order to achieve freedom from hysteresis, a torsionally stiff coupling has to be provided between a first end 22 of a coupling assembly 24 and the measuring system 20.

[0079] The coupling assembly 24 is mounted in a housing 30 of the rotary coupling arrangement by means of two bearings 26, 28. The housing 30 of the rotary coupling arrangement is shown merely schematically and already broken off; it can have any desired shape in principle. The coupling assembly 24 has a second end 32 opposite the first end 22 of the coupling assembly. A coupling device 33, in particular a recess, which is provided for the rotationally fixed coupling to a slip ring assembly 36, is provided in this second end 32.

[0080] The coupling assembly 24 is formed with an internal hollow space which allows electrical cable elements to be guided through from the sensor interface 12 to the slip ring assembly 36. The internal hollow space is formed along the rotation axis 14 in order to allow the cable elements to be guided through from the sensor interface 12 to the recess 33 without torsion.

[0081] A drive device 34 serves to rotate the coupling assembly 24. The drive device 34 can be formed as desired, for example an electric motor which drives the coupling assembly by means of a chain or belt drive can be provided. In particular, the drive device is intended to operate without lateral forces as far as possible. In principle, it can also be provided that the drive device is designed in the form of an electrical machine, wherein the coupling assembly is a rotor of this electrical machine.

[0082] The slip ring assembly 36 has a slip ring stator 38 and a rotor arrangement 40. The rotor arrangement 40 is described in detail below. The rotor arrangement 40 is connected to the coupling assembly 24 by way of the coupling device 33 in a rotationally fixed manner. Rotation of the coupling assembly 24, which rotation is initiated by the drive device 34, is therefore transmitted directly to the rotor arrangement 40 of the slip ring assembly 36. A stator 38 of the slip ring assembly 36 taps off the electrical signals from corresponding contacts of the rotor arrangement 40 and passes on said electrical signals by means of a corresponding cable element 42. A data transmission means 44 which can connect the cable element 42 to an evaluation and/or control device 46 is only schematically shown. The measuring system 20 can also be connected to the evaluation and/or control device 46 via this data connection 44.

[0083] The illustrated arrangement allows the coupling assembly 24, the slip ring assembly 36 and the measuring system 20 to be arranged one behind the other along the rotation axis 14. A rotary movement of the coupling assembly 24, which rotary movement is initiated by the drive device 34, is directly transmitted by means of the rotor arrangement 40 of the slip ring assembly 36. Furthermore, the rotor arrangement 40 is coupled to the measuring system 20, so that said measuring system can directly determine the rotation position. Dedicated mounting of the rotor arrangement 40 of the slip ring assembly 36 can therefore be dispensed with. Furthermore, a design of the rotary coupling arrangement 10, which design is particularly compact in respect of the diameter, is provided. It is therefore possible, for example, to provide the rotary coupling arrangement with an outside diameter of less than 20 mm, in particular less than 15 mm, in particular less than or equal to 13 mm.

[0084] FIG. 2a shows a cross-sectional view of one embodiment of a rotor arrangement 40.

[0085] The rotor arrangement 40 has a shaft element 48. The shaft element 48 is at least partially in the form of a hollow shaft. In the illustrated embodiment, the shaft element 48 is in the form of a hollow shaft throughout. The shaft element 48 has a first end 50. The first end 50, as illustrated in the cross section A-A, has a profile cross section 52. This means that the profile cross section 52 is not of round design. In the illustrated embodiment, it has flattened sections 54 in order to allow rotationally fixed coupling to the coupling assembly 24. A flange 56 is formed adjacent to the flat sections 54. The flange 56 has a cross section which is larger than that of the flattened section 54. An insulation 58 adjoins the flange 56 on an outer circumference of the shaft element 48. Said insulation extends over a portion of the outer circumference of a stem of the shaft element 48. A second end 60 is situated opposite the first end 50.

[0086] At the first end 50, a first end section 62 extends into the region of the flattened sections 54 in the longitudinal direction along the rotation axis 14. Said first end section extends as far as the flange 56. A middle section 64 of the shaft element 48 extends from the flange 56 as far as an end of the insulation 58. A second end section 66 of the shaft element 48 extends from the end of the insulation as far as the second end 60. The second end section 66 can be of hardened design in particular. A casing wall of the shaft element 48 is identified by 68; a hollow interior of the shaft element 48 is identified by reference symbol 70.

[0087] In principle, the shaft element 48 can also be formed from an electrically insulating material, for example from a ceramic material. The insulation 58 can then be saved.

[0088] In the illustrated embodiment, this insulation 58 is in the form of an adhesive layer 59 which can have, in particular, a minimum thickness of 0.1 mm. Said adhesive layer can be formed, in particular, in a recessed region of the middle section 64 which has a reduced cross section in relation to the second end section 66 for example. However, in an alternative, it can also be provided that the middle section and the second end section have identical diameters, in particular outside diameters, and the insulation 58 is in the form of a sleeve, in particular which is composed of plastic, which is pressed onto the middle section.

[0089] An insulating ring 74 is arranged so as to bear against the flange 56. Said insulating ring serves to insulate a first contact 76 from the flange. Radially on the inside, the contact ring 76 is electrically insulated from the shaft element by means of the insulation 58. The axial position of said contact ring can be fixed by an additional adhesive bond on the adhesive layer 59. A further contact ring is identified by reference symbol 92. Said further contact ring is fixed on the adhesive layer 59 in such a way that there is an air gap 77 or distance 77 between the contact ring 92 and the adjacent contact ring 76. Said air gap or distance can provide a corresponding insulating effect.

[0090] FIG. 2b shows a schematic cross-sectional view of a contact ring 76.

[0091] The contact ring 76 has a radial inner face 102, a radial outer face 100 and two side faces 104 and 106 which are opposite one another.

[0092] A cable element 72, which is associated with the contact ring 76, is fastened to one of the side faces 104, 106; to the side face 104 in the illustrated embodiment. In particular, the cable element 72 can be soldered to the side face 104. The cable element 72 is then guided into the interior 70 through a cutout 78 which extends through the insulation 58 and the shaft element 48. From there, said cable element can exit from the first end 50 through the first end section 62 and be guided, for example, into the coupling assembly 24. In particular, it can be provided that a cutout 78 is provided for each contact ring 76, 92. However, in principle, it can be provided that a plurality of cable elements 72 are guided through a cutout 78. For example, the cable elements 72 can be provided with an insulating layer for this purpose. In this way, it is possible to thread the insulating ring 74 and the contact rings 76, 92 onto the middle section 64 from the second end 60. In a further embodiment in which the insulation 58 is formed by a plastic sleeve, it can be provided that an insulating ring 74 and a contact ring 76, 78 are alternately arranged on the middle section 64. A corresponding electrical insulation can be provided between adjacent contact rings 76, 92 in this way too.

[0093] Furthermore, it can be provided, for example, that at least the last contact ring which is pushed onto the middle section 64 is pressed on in order to provide adequate fixing in the axial direction along the rotation axis 14 of the contact rings 76, 92 and the insulating rings 74. In principle, all or a plurality of the contact rings and/or insulating rings can also be pressed on. One or more rings can be pressed on when the insulation is in the form of an adhesive layer but also if the insulation 58 is in the form of a plastic sleeve.

[0094] FIG. 3 shows an isometric view of an embodiment of the shaft element 48. Identical elements are identified by the same reference symbols and will not be explained again below. A circumferential direction is identified by reference symbol 110. The illustrated shaft element has a total of fourteen cutouts. Seven of these cutouts are visible. Here, four cutouts 78, 80, 82, 84 are arranged in an axial row. Three further cutouts 86, 88, 90 are arranged in a further axial row. Seven further cutouts are not shown in this perspective. Here, two cutouts are arranged between cutout 86 and cutout 80 in the axial direction. Two cutouts are arranged between the cutouts 88 and 82. Two further cutouts are arranged between the cutouts 90 and 84. A further cutout is arranged between the cutout 78 and the flange. Furthermore, all of the cutouts are arranged offset in relation to one another in circumferential direction 110. This allows stability and therefore torsional stiffness of the shaft element 48 to be retained. The shaft element 48 is produced, in particular, from a steel alloy or from a ceramic material. In particular, the shaft element 48 is integrally produced. A plastic sleeve element is pushed onto the middle section 64. The cutouts 78 to 90 each extend through the sleeve element 91 and the shaft element 48. The shaft element 48 has a total of four axial rows of cutouts. The rows are offset in relation to one another in the circumferential direction 110. The cutouts are likewise offset in the axial direction along the rotation axis 14. Therefore, one cutout, through which a corresponding cable element 72 can be guided, can be provided for each of fourteen contact rings in this way, The second end section 66 does not have any cutouts. Here, the casing surface is of closed design over its entire circumference. The second end section 66 can be of hardened design. However, the entire shaft element 48 can be of hardened design overall.

[0095] FIG. 4 shows a fully assembled embodiment of the rotor arrangement 40. A total of fourteen contact rings, of which three, the contact rings 76, 92, 94, are provided with a reference symbol, are threaded onto the shaft element 48 illustrated in FIG. 3. The contact rings are threaded onto the middle section 64 alternately with insulating rings 74, 96, 98. In this way, said contact rings are electrically insulated from one another or from the flange 56. Said contact rings are insulated from the shaft element 48 radially on the inside by means of the insulation 58. In this way, fourteen cable elements 72 can be guided into the interior of the shaft element 48 and can be guided out at the first end 50 of said shaft element. A rotary coupling arrangement 10 for fourteen contacts can be provided in this way.

[0096] The interior of the shaft element 48 can be filled with an adhesive—in principle also the adhesive of the adhesive layer 59. The cutouts can also be filled with an adhesive. Fixing of the cable elements and strain relief can be provided in this way. As outlined above, the contact rings and the insulating rings can likewise be axially secured or fixed by means of a further adhesive bond on the adhesive layer 59.

[0097] The rotor arrangement 40 has a particularly large torsional stiffness on account of the continuous shaft element 48. In particular, the integral design and the material selection as steel alloy can also contribute to this. Bearing by means of the first end section in the coupling assembly 24 and by means of the second end section in the measuring system additionally allow arrangement of the rotor arrangement in the rotary coupling arrangement 10 without dedicated bearing. Hysteresis-free transmission of a rotary movement from a sensor interface 12 to the measuring system 20 given a compact design, in particular with a small outside diameter, is in this way possible. In this case, a free rotary movement n×360° for all fourteen contacts remains possible at the same time.