EP3231045A1

EP3231045A1 - Rotary coupling arrangement with a rotor arrangement for a slip-ring assembly

Info

Publication number: EP3231045A1
Application number: EP15807631.5A
Authority: EP
Inventors: Tobias Woletz; Dieter Kaufmann
Original assignee: Carl Zeiss Industrielle Messtechnik GmbH
Current assignee: Carl Zeiss Industrielle Messtechnik GmbH
Priority date: 2014-12-10
Filing date: 2015-12-04
Publication date: 2017-10-18
Anticipated expiration: 2035-12-04
Also published as: US10116110B2; DE102014118359A1; WO2016091756A1; EP3231045B1; US20170271833A1

Abstract

The present invention relates to a rotor arrangement (40) for a slip-ring assembly (36), with a shaft element (48) and at least one contact ring (76, 92, 94), wherein the shaft element (48) is at least partially designed as a hollow shaft with a hollow interior (70) and a casing wall (68), wherein the shaft element (48) has a middle portion (64), wherein each contact ring (76, 92, 94) is arranged in the middle portion (64) on the shaft element (48) and is electrically insulated in relation to the shaft element (48) by means of an insulating means (58), wherein the middle portion (64) has at least one recess (78, 80, 82, 84, 86, 88, 90) through the insulating means (58) and the casing wall (68) into the interior (70), wherein each contact ring (76, 92, 94) is connected to a cable element (72) which is guided through one of the one or more recesses (78, 80, 82, 84, 86, 88, 90) into the interior (70), and wherein the shaft element (48) has a first end portion (62) with an outer circumferential cross section (52) for the rotationally fixed coupling. Furthermore, a rotary coupling arrangement with such a rotor arrangement is proposed.

Description

ROTARY CLUTCH ASSEMBLY WITH A ROTOR ARRANGEMENT FOR ONE

SCHLEIFRING GROUP

The present invention relates to a rotor assembly for a slip ring assembly. Of

Further, the present invention relates to a rotary joint assembly having a slip ring assembly.

In the prior art, in particular in the field of coordinate metrology, it is customary to attach the sensors used to support structures that allow moving the sensors freely within a measuring space. The support structures are known in many forms, for example in the form of portal structures or horizontal arm structures. Frequently, the support structures on axes of rotation, which allow a rotation of an arrangement, for example. The sensor or, for example. Also, an intermediate rotary pivot joint by up to 360 °. Furthermore, completely freely rotatable Rotary axes used in which rotational movements over a multiple of 360 °

can be passed through. In addition to relatively large measuring spaces, such sensors are frequently also used in smaller designs in the field of coordinate measuring technology, for example when drilling holes or difficult-to-reach workpiece features. In general, efforts are also made to compact construction of the support structures and the axes of rotation used in order to obstruct the smallest possible measuring space through the support structure itself.

In the field of coordinate metrology are different measuring systems, both tactile

Art as well as optical type known. In addition, a distinction is made between measuring systems that perform a Einzelpunktantastung and those measuring devices that work with so-called "scanning method". In such scanning methods, during the tactile or optical probing of a workpiece, a specific path is traversed on the workpiece and a multiplicity of measuring points are recorded along the path. In particular, in such scanning method, it is of course imperative that the position of the axes of rotation and thus of the measuring system can be carried out with high accuracy in order to assign the corresponding exact spatial coordinate to the detected measuring points.

Especially with rotary axes or hinges, the rotational movements of a multiple of 360 °, so-called nx 360 ° movements to transfer, the use of slip ring assemblies is necessary. Depending on the available installation space, it may occur here that, starting from the sensor used, towards a measuring system for the rotational position, a rotational movement has to be transmitted via the slip ring assembly. This can cause hysteresis problems. Especially in the field of coordinate metrology, however, a hysteresis-free rotational movement and detection by a rotational position measuring system is absolutely necessary. Known slip rings are usually made by injection molding of plastic. Here, the contact rings used and the associated cables are encapsulated in plastic, the plastic then provides the required insulation between the individual contact rings and cables and at the same time provides the shaft body of a rotor element of a slip ring assembly. For modern sensors, however, many electrical contacts are now required. Is the number of cable elements to be provided large in size Compared to the available installation space, the problem may arise that a large part of the available shaft diameter is taken up by the electric cables themselves. There then remains very little space that can be injected with plastic, resulting in a very low torsional stiffness of the rotor shaft of the slip ring assembly. This can lead to twisting and even deformation of the slip ring rotor, which can cause undesirable hysteresis problems.

Particularly in the case of highly accurate, scanning-capable rotary axes, in particular in the field of coordinate metrology, these problems can occur if a transmission of the rotational movement via the slip ring assembly to a measuring system is necessary due to design or space constraints.

Although measuring systems for the rotational position are generally self-mounted, they still have a certain moment of resistance on the rotor of a slip ring assembly or on the entire axis of rotation coupled thereto. This also always causes a corresponding torsion of the slip ring rotor with insufficient rigidity of the slip ring rotor, which ultimately leads to the undesirable hysteresis.

Although solutions without slip rings would avoid the undesired hysteresis, but as a rule do not allow free rotation by rotation angle of more than 360 °. In the case of slip rings known from the market, which indeed allow rotational movements of more than 360 °, the necessary torsional rigidity is again not given.

Corresponding problems can also occur with the coordinate measuring machines, for example in the case of turntables or generally in the case of rotary axes or rotary joints in other applications which require compact designs and / or a low weight or moment of inertia.

The document DE 199 35 282 A1 shows a device for measuring a

Angle of rotation, in which the use of a slip ring is also being considered. The document DE 20 2009 017 928 U1 and the publication DE 10 2009 057 609 A1 show portable height gauge and scriber device which also proposes a slip ring assembly and the use of slip rings. The document DE 601 08 858 T2 shows a route measuring device or a curve length measuring device in which an electrical coupling means can be formed by one or more slip rings and one or more brushes.

The document DE 201 10 415 111 shows an inspection device for the dimensional and / or shape tolerances of a rotationally symmetrical surface of a workpiece, in which a supply and signal transmission device can be formed from a slip ring. The document DE 10 2008 028 403 A1 shows a Ansatzwegaufnehmer for measuring the change in length of a sample in which a friction clutch in the form of an adjustable spring-slip ring system can be performed. The document DE 31 33 477 C2 shows a device for measuring the surface flatness of a plate. The publication DD 249 523 A1 shows a device for error detection and error marking in non-conductive layers on electrically conductive material, which has a slip ring arrangement in the case. Furthermore, the document DE 100 52 360 A1 shows a device for measuring bores of a workpiece, in which a wiring harness is guided in a slip ring body. Furthermore, the document DE 295 19 61 1 U1 shows a rope length sensor, in particular for use in telescopic arms, which may have a slip ring assembly.

Despite all, however, there is still a need to solve the problems described above.

An object of the present invention is therefore to provide an improved rotor assembly for a slip ring assembly or a rotary coupling arrangement, which allows a hysteresis-free transmission of rotational movement and is particularly suitable for use in small spaces for transmitting rotational movements of more than 360 °.

According to a first aspect of the invention, therefore, a rotor assembly for a

Slip ring assembly proposed with a shaft member and at least one Contact ring, wherein the shaft member at least partially as a hollow shaft with a

hollow interior and a shell wall, the shaft member having a central portion, each contact ring being disposed in the central portion on the shaft member, the central portion having at least one recess through the shell wall in the interior, wherein each contact ring is connected to a cable element, which is guided through one of the at least one recess, into the interior space, and wherein the shaft element has a first end portion with an outer circumference cross-section for the rotationally fixed coupling.

It has been found that known slip ring assemblies not with a

continuous rotor shaft are provided. Rotor elements of known slip ring assemblies are, for example, produced by the above-mentioned injection molding or several thin sleeves are pressed into each other. However, this does not allow the required torsional stiffness in a free transmission of a rotary motion.

The provision of the rotor assembly with a hollow shaft with a hollow interior and

Mantle wall allows their interpretation according to the requirements of the number of electrical contacts, the resistance torque to be experienced and the available space. For the material of the hollow shaft, which may be formed in one piece in particular, a material with a high shear modulus, for example. A steel alloy or a ceramic material may be used. This provides the rotor assembly of a slip ring assembly with a torsionally stiff shaft member. The formation of one end of the shaft member having an outer circumferential cross-section to the non-rotatable coupling, in particular direct non-rotatable coupling, allows the coupling with a driven rotor assembly of a rotary coupling assembly and the direct transmission of the rotational movement to the rotor assembly of the slip ring assembly. In particular, it may thus also be possible to dispense with a self-supporting of the rotor arrangement within a stator of the slip ring assembly, for example via additional ball bearings. The proposed embodiment may, for example, make it possible to provide a maximum hysteresis of less than 10 arc seconds for a maximum outer diameter of the rotor assembly of a maximum of 13 mm and at least 14 contact rings or contacts to be transferred by the slip ring. An outer diameter of the contact rings can be for example 8 mm. Overall, a non-rotatable and stable in this way Coupling provided with simple extension of the rotor assembly to a rotational position measuring system.

An isolation of the contact rings relative to the shaft element is between a

Shell wall of the shaft member and the contact rings arranged. This can be formed, for example, as a pressed plastic sleeve. In this way, the contact rings can be threaded onto the shaft and come to rest on the plastic sleeve. The contact rings can then be arranged alternately with, for example. Also formed of plastic insulating rings, so that each contact ring is sufficiently insulated both with respect to the shaft member and against adjacent contact rings.

In the context of the following application, "electrically isolated" means that an electrical conductivity across a corresponding insulation is less than 10 ^-8 S / m or A / Vm or 1 / Qm Unit Siemens, m the unit meters, A the unit amperes, V the unit volts, Ω the unit ohms.

According to a second aspect of the invention, a rotary coupling arrangement or

A rotary joint interface, in particular for a coordinate measuring machine, proposed with a slip ring assembly with a rotor assembly according to the first aspect of the invention or one of its embodiments, comprising a rotatable coupling assembly having a first end and a second end opposite the first end, the first end having a coupling interface and wherein the second end has a slip ring assembly interface for rotationally fixed engagement with the first end portion of the rotor assembly, and a rotational position measurement system for determining a rotational position of the rotor assembly of the slip ring assembly.

The proposed rotary joint arrangement or rotary joint interface

allows the direct transmission of the rotational movement of the rotatable coupling assembly to the rotor assembly and thus the slip ring assembly. In this way, the rotational movement of the coupling assembly can be transmitted without self-storage of the slip ring assembly. Due to the stable coupling of the rotor assembly and the high inherent rigidity of the rotor assembly, even without bearing leranz the concentricity of less than 0.02 mm at one of the rotor assembly applied end of the rotor assembly can be maintained.

The object initially posed is therefore completely solved.

In one embodiment of the rotor assembly can be provided that the

Central portion opposite the first end portion is offset by a flange, wherein the flange has an outer diameter which is larger than a smallest outer diameter of the first end portion and larger than an outer diameter of the central portion.

In this way, a fixed contact for the contact rings can be provided and also an inertial moment of the rotor assembly can be increased.

Furthermore, it can be provided on an embodiment of the rotor assembly that a smallest diameter of the first end portion is greater than a diameter of the central portion.

In this way, also a large moment of inertia of the rotor assembly

to be provided. In addition, an introduced via the first end portion in the rotor assembly clutch torque due to the large outer diameter can be large.

In a further embodiment of the rotor assembly can be provided that the

Outer circumferential cross section of the first end portion is formed as a profile cross-section, in particular wherein the first end portion is formed flattened.

A "profile cross section" can be understood to mean any non-circular outer peripheral cross section. The profile cross-section allows to transmit a rotational movement by means of a non-rotatable coupling. Thus, the profile cross-section, for example, be triangular, square or n-square. Also, for example elliptical profile cross sections are possible. In a further embodiment it can be provided that the shaft element

is integrally formed.

In this way, the torsional rigidity of the shaft member can be improved and a hysteresis-free transmission of a rotary motion can be improved.

In a further embodiment it can be provided that the shaft member is formed of a material having a shear modulus of more than 75 gigapascals (GPa), in particular wherein the material of the shaft member is a steel alloy.

1 Pascal is 1 N / m ² or 1 kg / ms ² . Also in this way can the

Torsional stiffness of the shaft member can be increased. In particular, steel alloys can have a large shear modulus. However, unalloyed steels, for example unalloyed tool steels, may also already have a suitable torsional rigidity or a sufficiently high shear modulus.

Possible alloying elements for steel are, for example, chromium, vanadium, manganese,

Molybdenum, nickel, tungsten and / or cobalt.

In a further embodiment it can be provided that each contact ring is electrically insulated from the shaft element by means of insulation. Then, the at least one recess may be formed by the insulation and the jacket wall in the interior.

In this way, an electrical insulation between the contact rings and the

Shaft element may be provided, for example, when the shaft member is formed of a metallic material.

In a further embodiment it can be provided that the shaft element is formed of an electrically insulating material. In this way, an additional electrical insulation between the contact rings and the corrugated element is not necessary. For example, a plastic sleeve or an electrically insulating adhesive layer can then be saved. In principle, however, a plastic sleeve or an electrically insulating adhesive layer may nevertheless be provided as additional electrical insulation.

In a further embodiment it can be provided that the shaft member is formed of a material having a shear modulus of more than 100 GPa, in particular wherein the material of the shaft member is a ceramic material. For example, the material of the shaft element may be a silicon carbide ceramic material.

In this way, an even higher shear modulus while electrical

Isolation to be provided.

In a further embodiment, it may be provided that the rotor assembly comprises more than one contact ring, and wherein in each case between two adjacent contact rings, an adjacent insulating rings electrically insulating insulating ring is arranged.

In particular, the insulating ring can also be formed here from a workpiece having an electrical conductivity of less than 10 ^"8 amps per voltmeter or AA.sup.-m. In this way, adjacent contact rings can be easily electrically insulated from one another simply be alternately pushed onto the shaft element.

In a further embodiment it can be provided that on the flange on the

Middle section is arranged an electrically insulating isolation ring.

In this way, it is just as possible, the flange of the shaft member

to isolate against the closest arranged to the flange contact ring. Again, in turn, the workpiece of the insulating ring have an electrical conductivity of less than 10 ^"8 A / Vm.

In a further embodiment it can be provided that the insulation is formed as a sleeve made of an electrically insulating material, which is arranged on the central portion of the shaft member.

In this way, it is particularly easy to provide the insulation between the contact rings and the shaft element in the radial direction. The contact rings can simply be pushed onto the sleeve. In particular, the sleeve can be made of a plastic. In particular, the sleeve can then be pressed onto the shaft element or the middle section of the shaft element.

In particular, the advantage becomes clear that in the proposed rotor arrangement, the insulation and the support structure or the shaft element are separated from each other. The shaft element here alone serves for the torsionally rigid transmission of the rotational movement, so that a hysteresis-free measurement of the rotational position becomes possible. The insulation of the contact rings is then, for example, on the proposed sleeve or else, as will be explained below, by an adhesive layer and by also similarly deferred insulation rings.

In a further embodiment of the present invention it can be provided that the insulation is formed as an adhesive layer, wherein the adhesive layer is provided by means of an adhesive of an electrically insulating material. In this case, the adhesive layer may have a thickness of at least 0.1 mm.

Such an adhesive layer may, for example, also make it possible to fix the contact rings on the shaft element in the longitudinal direction adjacent to one another in such a way that an air gap exists between adjacent contact rings. Then, for example, insulation rings can be omitted. For the adhesive layer, a minimum thickness of at least 0.1 mm may be provided to provide sufficient insulation from the shaft member. In particular, a thickness of the adhesive layer of 0.15 mm be provided. In particular, the adhesive layer can be applied to the shaft element, in particular be applied with rotating shaft element. After curing, the adhesive can then be turned to the desired thickness. In this way, electrical insulation can be provided in a very thin and space-saving manner in direct connection with the shaft element. The contact rings can then for example likewise be arranged on the adhesive layer and can be fixed on the adhesive layer and thus on the shaft element by means of the adhesive, in particular an additional application of adhesive.

In a further embodiment, it can be provided that the shaft element has a second end portion opposite the first end portion, in which the casing wall is closed over its entire surface. The corrugated element can be designed as a hollow shaft throughout. In this case, however, in particular the jacket wall of the entire end can be closed in the second end portion and have no mismatches.

The central portion is thus between the first end portion and the second

Arranged end portion.

The second end section is used in particular for coupling with a rotational position measuring system. The second end portion may be hardened. In this way it becomes possible to provide a steel or steel alloy shaft journal as the input interface for the rotational position measuring system. The second end portion may then be disposed in or on the rotational position measuring system. An additional shaft journal is no longer provided between the slip ring assembly and the rotational position measuring system. Further hysteresis influences can thus be avoided.

In particular, it is thus possible to arrange a coupling assembly, a slip ring assembly and a rotational position measuring system in series along a common axis of rotation, thus providing a compact arrangement which occupies little space. In one embodiment, it may be provided that each contact ring on the

Middle section is glued.

In particular, it can be provided that respectively adjacent contact rings are arranged on the central portion such that an air gap remains between them.

In other words, adjacent contact rings are spaced apart from each other

Middle section arranged.

In this way, sufficient isolation between adjacent

Be provided contact rings. For example, this can be provided with a same number of contact rings a small axial length of the rotor assembly.

In a further embodiment it can be provided that each contact ring has a radial inner surface, a radial outer surface and two side surfaces, and wherein each contact ring is connected to one of its side surfaces with a cable element.

In this way, for example, be provided that the cables are soldered to the contact rings side. In this way, the cables can be soldered prior to assembly to the rings and after the threading of the rings on the shaft member, the cables are individually guided through the corresponding recess in the interior of the shaft member.

In a further embodiment it can be provided that the rotor arrangement has at least fourteen contact rings.

In this way, at least fourteen or a corresponding number of electrical contacts can be provided. In particular, with such a high number of contacts, in which conventional injection-molded rotor assemblies are not suitable, a suitable torsional stiffness can be provided despite the high number of contacts. In one embodiment, it can be provided that the rotor arrangement has a number of recesses which corresponds to the number of contact rings.

In this way, a separate recess is then provided for each cable element.

In a further embodiment it can be provided that the rotor arrangement has at least one first recess and one second recess, wherein the first recess and the second recess are formed offset in the circumferential direction to each other in the central portion.

This makes it possible, for example, to provide a separate recess for each contact ring, without, however, reducing the torsional rigidity of the shaft element by means of recesses which are spaced too closely from one another. The distribution in the circumferential direction makes it possible to provide a plurality of recesses, in particular a number of recesses corresponding to the number of contact rings. However, it is also possible that, for example, a number of recesses is provided, which corresponds to half the number of contact rings. In this case, two contact rings would share a recess. Then two cable elements would be passed through a recess.

In one embodiment of the rotary joint assembly may be provided that the rotary joint assembly comprises a drive means which is coupled to the clutch assembly to rotate or drive the clutch assembly.

In this way it is possible by force or torque introduction in the

Coupling assembly with appropriately designed loop to achieve a high positioning accuracy.

In a further embodiment of the rotary coupling arrangement can be provided that the rotor assembly is a rotor assembly in which the shaft member has a first end portion opposite the second end portion in which the shell wall is closed over the entire surface, and wherein the second end portion in the Rotary position measuring system is arranged. Furthermore, the second end portion may be disposed on the rotational position measuring system. In particular, the second end portion may be arranged in a direction along the rotational axis of the shaft member overlapping with the rotational position measuring system. In particular, the rotor assembly may be cantilevered in the rotor assembly.

In this way, the rotary joint arrangement with an arrangement "in series" of

Coupling assembly, slip ring assembly and rotational position measuring system is provided, wherein between the coupling assembly, a direct transmission of the rotational movement via the rotor assembly of the slip ring assembly is provided in the rotational position measuring system. The shaft element of the rotor assembly of the slip ring assembly is continuously provided by the clutch assembly in the rotational position measuring system. With little space in this way a hysteresis-free direct transmission of the rotational movement of the coupling assembly is made possible in the rotational position measuring system. Furthermore, due to the direct coupling of the slip ring assembly or the rotor assembly of the slip ring assembly with coupling assembly and the rotational position measuring system can basically be dispensed with a self-supporting the rotor assembly of the slip ring assembly. This can avoid the introduction of additional torques and / or friction forces and thus additional hysteresis influences.

It is understood that the above and the still to follow

explanatory features are usable not only in the combination given, but also in other combinations or alone, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description. Show it:

1 shows an embodiment of a rotary joint arrangement,

2a shows an embodiment of a rotor assembly, 2b is a schematic cross-sectional view of a contact ring,

Fig. 3 is a symmetrical view of an embodiment of a shaft member of a rotor assembly, and

Fig. 4 shows an embodiment of a rotor assembly.

Fig. 1 shows an embodiment of a rotary joint assembly 10. Such

Rotary coupling assembly 10 can be used in particular in coordinate measuring machines. It serves, for example, to rotatably couple a sensor to a carrier structure. In particular, the rotation can be freely given by a multiple of 360 °, a so-called n x 360 ° rotatability. The dimensioning of the rotary coupling arrangement is freely selectable. In addition, other applications are conceivable, for example. For turntables or in other applications, if rotary axes should be free to pivot more than 360 °. The use of the rotary joint assembly 10 in a coordinate measuring machine where it is used for coupling to a sensor will now be described.

For this purpose, the rotary coupling arrangement 10 has a sensor interface 12. At the

Sensor interface 12, a sensor can be arranged, which is then freely rotatable about an axis of rotation 14. In the illustrated embodiment, the rotary coupling arrangement must ensure that a rotational movement at a sensor-side end, which is designated by an arrow 16, is identical to a rotational movement at an opposite end, which is designated by an arrow 18. Rotational movements 16 and 18 would have to be hysteresis-free and identical in order to be able to detect a rotational position of a sensor at the sensor interface 12 without hysteresis by means of a rotational position measuring system 20.

To hysteresis freedom, a torsionally rigid coupling between a first end 22 of a coupling assembly 24 and the measuring system 20 must be provided. The clutch assembly 24 is supported by two bearings 26, 28 in a housing 30 of the rotary joint assembly. The housing 30 of the rotary coupling arrangement is shown only broken off schematically, it may in principle have any shape. Opposite to the first end 22 of the clutch assembly, the clutch assembly 24 has a second end 32. In this second end 32, a coupling device 33, in particular a recess, is provided, which is provided for the rotationally fixed coupling with a slip ring assembly 36.

The coupling assembly 24 is formed with an internal cavity having a

Implementation of electrical cable elements from the sensor interface 12 to the slip ring assembly 36 allows. The inner cavity is designed along the axis of rotation 14 in order to allow a torsion-free passage of the cable elements from the sensor interface 12 to the recess 33.

To rotate the clutch assembly 24 is a drive means 34. Die

Drive means 34 may be of any desired design, for example. An electric motor may be provided which drives the clutch assembly by means of a chain or belt drive. In particular, the drive device should act as free of lateral force as possible. In principle, it can also be provided that the drive device is designed in the form of an electric machine, wherein the coupling assembly is a rotor of this electric machine.

The slip ring assembly 36 includes a slip ring stator 38 and a rotor assembly 40. The rotor assembly 40 is described in detail below. The rotor assembly 40 is rotatably connected to the coupling assembly 33 with the coupling assembly 24. Rotation of the clutch assembly 24 initiated by the driver 34 is thus transferred directly to the rotor assembly 40 of the slip ring assembly 36. A stator 38 of the slip ring assembly 36 detects the electrical signals at corresponding contacts of the rotor assembly 40 and passes them on via a corresponding cable element 42 on. Only schematically illustrated is a data transmission 44, which can connect the cable element 42 with an evaluation and / or regulating device 46. Also, the measuring system 20 may be connected via this data connection 44 with the evaluation and / or regulating device 46. The illustrated arrangement allows the coupling assembly 24, the

Slip ring assembly 36 and the measuring system 20 in a row along the rotation axis 14 to be arranged. A rotational movement of the coupling assembly 24 initiated by the drive device 34 is transmitted directly to the slip ring assembly 36 via the rotor assembly 40. The rotor assembly 40 is further coupled to the measuring system 20 so that it can directly determine the rotational position. A self-storage of the rotor assembly 40 of the slip ring assembly 36 can thus be avoided. Furthermore, a particularly compact diameter of the rotary coupling assembly 10 is provided. For example, it becomes possible to provide the rotary joint assembly with an outer diameter of less than 20 mm, in particular less than 15 mm, in particular less than or equal to 13 mm. FIG. 2 a shows a cross-sectional view of an embodiment of a rotor assembly 40.

The rotor assembly 40 includes a shaft member 48. The shaft member 48 is at least partially formed as a hollow shaft. In the illustrated embodiment, the shaft member 48 is continuously formed as a hollow shaft. The shaft member 48 has a first end 50. The first end 50 has, as shown in the cross section A-A, a profile cross-section 52. This means that the profile cross-section 52 is not circular. In the illustrated embodiment, it has flattened portions 54 to enable a rotationally fixed coupling with the coupling assembly 24. Adjacent to the flattened portions 54, a flange 56 is formed. The flange 56 has a cross section larger than that of the flattened portion 54. An insulation 58 adjoins the flange 56 on an outer circumference of the shaft element 48. This extends over a part of the outer circumference of a shaft of the shaft element 48. Opposite to the first end 50 is a second end 60.

At the first end 50 in the region of the flattened portions 54 extends longitudinally along the axis of rotation 14, a first end portion 62. This extends to the flange 56. From the flange 56 to one end of the insulation 58 extends a central portion 64 of Shaft element 48. From the end of the isolation up to the second end 60 extends a second end portion 66 of the shaft member 48. The second end portion 66 may be formed in particular hardened. A shell wall of the shaft member 48 is denoted by 68, a hollow interior of the shaft member 48 is designated by the reference numeral 70.

In principle, the shaft element 48 may also be formed from an electrically insulating material, for example from a ceramic material. Then the insulation 58 can be saved.

In the illustrated embodiment, this insulation 58 is formed as an adhesive layer 59, which may in particular have a minimum thickness of 0.1 mm. This can in particular be formed in a recessed region of the middle section 64, which, for example, has a reduced cross-section with respect to the second end section 66. In an alternative, however, it can also be provided that the middle section and the second end section have identical diameters, in particular outer diameters, and the insulation 58 is designed as a sleeve, in particular made of a plastic, pressed onto the central section.

Adjacent to the flange 56, an insulating ring 74 is arranged. This serves to isolate a first contact ring 76 from the flange. Radially inside, the contact ring 76 is electrically isolated from the shaft member by means of the insulation 58. Its axial position can be fixed by an additional bond on the adhesive layer 59. Another contact ring is designated by the reference numeral 92.

This is so fixed on the adhesive layer 59, that between the contact ring 92 and the adjacent contact ring 76, an air gap 77 and 77 distance is present. This can provide a corresponding insulation effect.

2 b shows a schematic cross-sectional view of a contact ring 76. The contact ring 76 has a radial inner surface 102, a radial outer surface 100 and two mutually opposite side surfaces 104 and 106. A cable element 72 associated with the contact ring 76 is attached to one of

Side surfaces 104, 106, fixed in the illustrated embodiment of the side surface 104. In particular, the cable element 72 may be soldered to the side surface 104. The cable element 72 is then guided through a recess 78, which extends through the insulation 58 and the shaft member 48, into the inner space 70. As such, it may exit the first end 50 through the first end portion 62 and, for example, be guided into the clutch assembly 24. In particular, it can be provided that a recess 78 is provided for each contact ring 76, 92. In principle, however, it can be provided that a plurality of cable elements 72 are guided through a recess 78. For example, for this purpose, the cable elements 72 may be provided with an insulating layer. In this way it is possible, from the second end 60 ago the insulation ring 74 and the contact rings 76, 92 aufzufädeln on the central portion 64. 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 central portion 64. Also in this way may be provided between adjacent contact rings 76, 92, a corresponding electrical insulation.

Furthermore, it can be provided, for example, that at least the last, on the

Central portion 64 aufzuschiebende contact ring is pressed to provide sufficient fixation in the axial direction along the axis of rotation 14 of the contact rings 76, 92 and the insulating rings 74. In principle, all or more of the contact rings and / or insulation rings can be pressed. The pressing of one or more rings can be carried out when the insulation is formed as an adhesive layer, but also if the insulation 58 is formed as a plastic sleeve.

FIG. 3 shows an isometric view of one embodiment of the shaft member 48.

Identical elements are identified by the same reference numerals and will not be explained again below. A circumferential direction is designated by the reference numeral 1 10. The illustrated shaft element has a total of fourteen recesses. Of which seven recesses are visible. Four recesses 78, 80, 82, 84 are arranged in an axial row. Three further recesses 86, 88, 90 are arranged in a further axial row. Seven are not recognizable from the perspective more recesses. There are two recesses in the axial direction between

Recess 86 and 80 arranged. Two recesses between the recesses 88 and 82. Two more recesses between the recesses 90 and 84. Another recess is disposed between the recess 78 and the flange. Furthermore, all recesses in the circumferential direction 1 10 are arranged offset from each other. This makes it possible to maintain stability and thus torsional rigidity of the shaft member 48. The shaft element 48 is in particular made of a steel alloy or of a ceramic material. In particular, the shaft member 48 is made in one piece. On the central portion 64, a plastic sleeve member is pushed. The recesses 78 to 90 extend through the sleeve member 91 and the shaft member 48, respectively. Overall, the shaft member 48 has four axial rows of recesses. The rows are offset from each other in the circumferential direction 1 10. In the axial direction along the axis of rotation 14, the recesses are also offset. In this way, a recess can thus be provided for fourteen contact rings, can be guided by the corresponding cable element 72. The second end portion 66 has no recesses. Here, the lateral surface is formed completely closed. The second end portion 66 may be hardened. But it can be formed hardened overall, the entire shaft member 48.

Fig. 4 shows a fully assembled embodiment of the rotor assembly

40. On the shaft element 48 shown in Fig. 3 a total of fourteen contact rings are threaded, three of which are provided with a reference numeral, the contact rings 76, 92, 94. The contact rings are alternately threaded with insulating rings 74, 96, 98 on the central portion 64 , In this way, they are electrically isolated from each other or from the flange 56. By means of the insulation 58, they are insulated radially inwardly with respect to the shaft element 48. In this way, fourteen cable elements 72 are guided in the interior of the shaft member 48 and can be led out at the first end 50. In this way, a rotary coupling arrangement 10 can be provided for fourteen contacts.

The interior of the corrugated element 48 can with an adhesive - in principle also the

Adhesive of the adhesive layer 59 - be filled. The recesses may also be filled with an adhesive. In this way, a fixation of the cable elements and a Strain relief be provided. As stated above, the contact rings and the insulation rings can also be fixed or fixed axially on the adhesive layer 59 by means of a further bond.

The rotor assembly 40 has a particularly high torsional rigidity due to the continuous shaft member 48. In particular, this can also contribute to the one-piece design and the choice of materials as a steel alloy. The mounting by means of the first end portion in the coupling assembly 24 and by means of the second end portion in the measuring system also allow an arrangement of the rotor assembly in the rotary coupling assembly 10 without bearing. In this way, in a compact design, in particular with a small outer diameter, a hysteresis-free transmission of a rotational movement from a sensor interface 12 to the measuring system 20. At the same time a free rotational movement n x 360 ° for all fourteen contacts remains possible.

Claims

claims

A rotor assembly (40) for a slip ring assembly (36) comprising a shaft member (48) and at least one contact ring (76, 92, 94), said shaft member (48) being at least partially a hollow shaft having a hollow interior (70) and a shell wall (48). 68), said shaft member (48) having a central portion (64), each contact ring (76, 92, 94) being disposed in said central portion (64) on said shaft member (48), said central portion (64) being at least a recess (78, 80, 82, 84, 86, 88, 90) through the shell wall (68) into the interior space (70), each contact ring (76, 92, 94) being connected to a cable element (72), which is guided through one of the at least one recess (78, 80, 82, 84, 86, 88, 90) into the interior space (70), and wherein the shaft element (48) has a first end section (62) with an outer circumferential cross section (FIG. 52) for non-rotatable coupling.

A rotor assembly according to claim 1, characterized in that the central portion (64) is offset from the first end portion (62) by a flange (56), the flange (56) having an outer diameter greater than a smallest outer diameter of the first end portion (56). 52) and larger than an outer diameter of the central portion (64).

Rotor assembly according to claim 1 or 2, characterized in that a smallest outer diameter of the first end portion (62) is greater than an outer diameter of the central portion (64).

Rotor arrangement according to one of claims 1 to 3, characterized in that the outer peripheral cross section (52) of the first end portion (62) is designed as a profile cross section, in particular wherein the first end portion (62) is formed flattened.

5. Rotor arrangement according to one of claims 1 to 4, characterized in that the shaft element (48) is integrally formed.

6. Rotor arrangement according to one of claims 1 to 5, characterized in that the shaft member (48) is formed of a material having a shear modulus of more than 75 GPa, in particular wherein the material of the shaft member (48) is a steel alloy.

A rotor assembly according to any one of claims 1 to 6, characterized in that each contact ring is electrically isolated from the shaft member (48) by means of insulation (58), in particular wherein the at least one recess (78, 80, 82, 84, 86, 88, 90) is formed by the insulation (58) and the jacket wall (68) in the interior space (70).

8. Rotor arrangement according to one of claims 1 to 7, characterized in that the shaft element (48) is formed of an electrically insulating material.

9. Rotor arrangement according to one of claims 1 to 8, characterized in that the shaft member (48) is formed of a material having a shear modulus of more than 100 GPa, in particular wherein the material of the shaft member (48) is a ceramic material.

10. Rotor assembly according to one of claims 1 to 9, characterized in that the rotor assembly (40) more than one contact ring (76, 92, 94), and wherein in each case between two adjacent contact rings (76, 92, 94) one of the adjacent Contact rings (76, 92, 94) electrically insulating insulation ring (96, 98) is arranged.

1 1. Rotor arrangement according to one of claims 2 to 10, characterized in that on the flange (56) on the central portion (64) an electrically insulating insulating ring (74) is arranged.

12. Rotor assembly according to one of claims 7 to 1 1, characterized in that the insulation is formed as a sleeve made of an electrically insulating material, which is arranged on the central portion (64) of the shaft member (48).

13. Rotor arrangement according to one of claims 7 to 12, characterized in that the insulation (58) as an adhesive layer (59) is formed, wherein the adhesive layer (59) is provided by means of an adhesive of an electrically insulating material, in particular wherein the adhesive layer has a thickness of at least 0.1 mm.

14. Rotor arrangement according to one of claims 1 to 13, characterized in that the shaft member (48) has a first end portion opposite the second end portion (66) in which the jacket wall (68) is closed over the entire surface.

15. Rotor assembly according to claim 13 or 14, characterized in that each contact ring (76, 92, 94) is glued to the central portion (64).

16. A rotor assembly according to claim 15, characterized in that each adjacent contact rings (76, 92, 94) are arranged on the central portion (64) that between you an air gap (77) remains.

17. A rotor assembly according to any one of claims 1 to 16, characterized in that each contact ring (76, 92, 94) has a radially inner surface (102), a radial outer surface (100) and two side surfaces (104, 106), and wherein each contact ring ( 76, 92, 94) is connected to one of its side surfaces with a cable element (72).

18. Rotor arrangement according to one of claims 1 to 17, characterized in that the rotor assembly (40) has at least fourteen contact rings (76, 92, 94).

A rotor assembly according to any one of claims 1 to 18, characterized in that the rotor assembly (40) has a number of recesses (78, 80, 82, 84, 86, 88, 90) corresponding to the number of contact rings (76, 92 , 94).

20. Rotor arrangement according to one of claims 1 to 19, characterized in that the rotor assembly (40) at least a first recess (78, 80, 82, 84, 86, 88, 90) and a second recess (78, 80, 82, 84, 86, 88, 90), wherein the first recess (78, 80, 82, 84, 86, 88, 90) and the second recess (78, 80, 82, 84, 86, 88, 90) in the circumferential direction (1 10) offset from each other in the central portion (64) are formed.

21. A rotary joint assembly (10), in particular for a coordinate measuring machine, comprising a slip ring assembly 36 having a rotor assembly (40) according to any of claims 1 to 20, a rotatable coupling assembly (24) having a first end (22) and a first end opposite second end (32), the first end (22) having a coupling interface (12), and the second end (32) having a slip ring assembly interface (33) for rotationally fixed coupling with the first end portion (62) of the rotor assembly (40) , and a rotational position measuring system (20) for determining a rotational position of the rotor assembly (40) of the slip ring assembly (36).

The rotary joint assembly according to claim 21, characterized in that the rotary joint assembly (10) includes drive means (34) coupled to the clutch assembly (24) for rotating the clutch assembly (24).

23. The rotary joint assembly of claim 21 or 22, characterized in that the rotor assembly (40) is a rotor assembly according to claim 14, and wherein the second end portion (66) is arranged on or in the rotational position measuring system (20).