(19)
(11)EP 3 540 486 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
24.06.2020 Bulletin 2020/26

(21)Application number: 18162195.4

(22)Date of filing:  16.03.2018
(51)International Patent Classification (IPC): 
G02B 6/36(2006.01)

(54)

COMPACT MULTICHANNEL OPTICAL ROTARY JOINT

KOMPAKTES MEHRKANALIGES OPTISCHES DREHGELENK

JOINT ROTATIF OPTIQUE MULTICANAL COMPACT


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
18.09.2019 Bulletin 2019/38

(73)Proprietor: Schleifring GmbH
82256 Fürstenfeldbruck (DE)

(72)Inventors:
  • Popp, Gregor
    80636 München (DE)
  • Abenhaim, Jacques
    82256 Fürstenfeldbruck (DE)

(74)Representative: Lohr, Jöstingmeier & Partner 
Junkersstraße 3
82178 Puchheim/München
82178 Puchheim/München (DE)


(56)References cited: : 
WO-A2-2007/010362
US-A- 5 371 814
US-A- 5 176 331
US-A1- 2007 184 934
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the invention



    [0001] The invention relates to Multi-channel rotary joints for optical signals. Such rotary joints a capable of simultaneously coupling a plurality of optical signals between two devices which are rotatable against each other.

    Description of the related art



    [0002] Optical rotary joints for simultaneous coupling of a plurality of optical signals between two units which are rotatable against each other, preferably have a derotating element. Such a derotating element may be a Dove prism which is rotated with half the angular speed of the relative rotation of the two units. On both sides of the Dove prism, collimators are provided for beam forming. The collimators provide a parallel beam of light from the light coupled by an optical fiber, and provide an increased beam diameter which is significantly larger than the fiber diameter.

    [0003] WO 2007/010362 A2, US 2007/0184934 A1, US 5,371,814 and US 5,271,076 disclose such a multi-channel fiber optic rotary joint, where a Dove prism is held rotatably within an outer housing. The design is optimized for a shortest-possible optical path between the two collimators, such that mechanical tolerances, specifically in the alignment of the collimators and the Dove prism, have the smallest-possible effect on signal transmission or attenuation. Therefore, the collimators are mounted as close as possible on both sides of the Dove prism.

    [0004] US 5,157,745 discloses a further multi-channel fiber optic rotary joint. Here, cylindrical lenses and lateral adjustors are provided to compensate for mechanical tolerances of the collimators and the Dove prism.

    [0005] US 5,176,331 discloses a rotation compensation device for a cable drum.

    [0006] US 5,442,721 discloses a comparatively short rotary joint using all lens collimators. A very important aspect of these rotary joints is their comparatively short optical path which helps to minimize the adverse effects of angular deviation of the optical paths and therefore reduces coupling losses.

    [0007] The optical fibers attached to the collimators typically leave the housings parallel to the rotation axis. There are alternative designs where the fibers are bent by 90 degrees to leave the housing perpendicular/orthogonal to the rotational axis. Since optical fibers are available that allow a tight bending radius of e.g. 2.5mm at tolerable attenuation increase and life time reduction this is a solution allowing short collimators with small dimension in axial direction. Other implementations are disclosed in US7876985B2.

    Summary of the invention



    [0008] The problem to be solved by the invention is to provide a multi-channel rotary joint which has a comparatively small outer diameter. It should have comparable or even lower coupling losses than the rotary joints known from prior art. Therefore, the rotary joint should provide a high mechanical and optical precision and therefore comparatively low mechanical tolerances. Manufacturing and assembly should be easy and simple, keeping the overall costs low. Furthermore, the design should be usable for high rotational speeds.

    [0009] Solutions of the problem are described in the independent claims. The dependent claims relate to further improvements of the invention.

    [0010] In a first embodiment, an optical rotary joint comprises a housing, a hollow shaft, a bevel gear, a derotating element like a prism, and two collimators. The rotary joint has a center axis. The housing comprises two housing sections which are separated by a gap in an axial direction. The gap is large enough to hold the bevel gear, as will be shown later. The housing sections are rotatable against each other around the center axis. The first housing section has in axial direction a first inner side and a first outer side. The second housing section has in axial direction a second inner side and a second outer side. The first inner side of the first housing section is oriented towards the second inner side of the second housing section. The outer sides of the housings preferably bear collimators, such that preferably a first collimator is arranged at the first outer side of the first housing section, and a second collimator is arranged at the second outer side of the second housing section.

    [0011] The hollow shaft is arranged essentially within the housing sections and aligned with the center axis. The hollow shaft has a first end which extends into the first housing section, and a second end which extends into the second housing section. The first housing section is supported on the first end of the shaft by at least one bearing, preferably by two, three or four bearings. The second housing section is supported on the second end of the shaft by at least one bearing, preferably by two, three or four bearings. Furthermore, the first housing may in addition be supported by at least one bearing, preferably by two, three or four bearings on the second end of the shaft. The hollow shaft further has a prism holder between the first and the second end. The prism holder is further preferably located within the first housing section.

    [0012] The bevel gear is located in the gap between the first housing section and the second housing section. It comprises three wheels. A first wheel is at the first inner side of the first housing section. A second wheel is at the second inner side of the second housing section, At least one third wheel is arranged, such that it meshes with the first wheel and the second wheel. The first and second wheels are coaxial to the center axis and opposing to each other, such that the first wheel opposes to the second wheel. Preferably, the first wheel and the second wheel have the same diameter, have preferably the same size, and most preferably are identical to each other. The at least one third wheel has an axis which is oriented radially to the center axis. The axis is fixedly attached to the hollow shaft or is one part with the hollow shaft. Therefore, when the housing sections are rotated against each other, causing the first and the second wheel to rotate, the third wheel will also rotate and generate a rotation of the hollow shaft around the center axis. The rotational speed of the hollow shaft is precisely half the speed of the housing sections relative to each other. Furthermore, the bevel gear is displaced in an axial direction from the prism holder, such that the axis of the third wheel in connection with the hollow shaft is comparatively short, and the third wheel is comparatively close to the hollow shaft. This allows to keep the outer diameter of the rotary joint comparatively small. Actually, it may be build such that the Dove prism, which is located in the prism holder outer the hollow shaft, is the largest component and defines the outer diameter of the whole rotary joint. For best precision, at least one bearing is on each side of the prism holder. Furthermore, it is preferred to have at least one bearing on each side of the bevel gear. Furthermore, preferably two bearings are within each housing section.

    [0013] As the prism in the prism holder and the bevel gear are arranged along the hollow shaft and therefore are separated in an axial direction, the outer diameter of the rotary joint can be minimized to the diameter of the largest component, which usually is the Dove prism. Furthermore, this design is usable to very high rotational speeds, as the diameter is very small and therefore the centrifugal forces are low. As the main extension of the rotary joint is in axial direction along the center axis, the distances between the bearings are comparatively large, which allows for a stable support of the components without having the risk of tilting or oscillations during operation.

    [0014] The bevel gear may comprise only one third wheel, but it is preferred to have at least one two or a higher number, like three or four or more third wheels. Preferably, the third wheels are arranged equidistant around the hollow shaft. This evenly distributes the forces to the hollow shaft and therefore increases precision. To avoid oscillation at high rotational speeds, it may be desirable to have slightly different distances between the third wheels.

    [0015] To have a compact assembly, it is preferred if the third wheel has a smaller diameter than the first and the second wheel. For a compact assembly, the third wheel may also have a simplified bearing, like a friction bearing or a plane bearing. For high rotational speeds, it may also have a ball bearing.

    [0016] Preferably, the housing has a cylindrical outer contour, and most preferably the first housing section has the same outer diameter as the second housing section. It is further preferred to provide a cover on the gap which may be connected either the first or the second housing section and rotate freely with respect to the other housing section.

    [0017] Preferably, the prism holder is a section of the hollow shaft for holding and/or accommodating the prism. The prism holder may also be part of the hollow shaft itself. It may also be a separate part held by the hollow shaft. Such a separate part simplifies assembly. It may also allow to adjust the prism within the holder before assembly with the hollow shaft. If the prism holder is a part of the shaft, then the prism may be mounted directly (e.g. by gluing) into the shaft.

    [0018] Preferably, the prism holder has an outer diameter larger than the outer diameter of the first end of the hollow shaft and the second end of the hollow shaft. Normally, the usable cross-section of a Dove prism is less than the height and the width of the Dove prism. Furthermore, some material is needed for the prism holder to hold the prism precisely at a predetermined position with respect to the center axis. An inner bore of the hollow shaft is required with such a diameter that all the collimated beams from the collimator may be guided between the collimators and the Dove prism. Due to the smaller usable cross-section of the Dove prism, the total area of the beams is significantly smaller than the height and the width of the Dove prism, and it is further significantly smaller than the prism holder. As the bearings between the hollow shaft and the housing sections are on the first end and second end of the hollow shaft, but not on the prism holder, these bearings have an inner diameter which is preferably smaller than the outer diameter of the prism holder.

    [0019] In a further embodiment, the bevel gear is a crown gear which preferably uses crown wheels. Such a crown gear is a specific modification of a bevel gear, where the wheels have an angle of 90 degrees with respect to their axis, and the teeth of the wheels are basically directed parallel to the axis.

    [0020] A method for adjusting the bevel gear of an optical rotary joint, for example as mentioned above, comprises a first step in which the whole unit is assembled by using means having a surface coating. The surface coating may have a predetermined coating thickness, preferably in the range between 1 µm and 30 µm. In a second step, the unit is disassembled and uncoated wheels or wheels with a thinner coating are inserted. Now, there is some mechanical play between the wheels due to the thickness difference the first set of wheels having a thicker coating and the second set of wheels having a thinner coating. This play allows for lower movement forces and for better rotation of the wheels.

    Description of Drawings



    [0021] In the following the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with reference to the drawings.
    Figure 1
    shows a sectional view of a first embodiment.
    Figure 2
    shows an outer view of the rotary joint.
    Figure 3
    shows a further outer view.
    Figure 4
    shows an embodiment with removed cover.
    Figure 5
    shows details of the gear.


    [0022] In Figure 1, a sectional view of a first embodiment is shown. The optical rotary joint 100 comprises a housing 200, a hollow shaft 300, a bevel gear 400, a derotating element like a prism 500, and two collimators 610, 620. The rotary joint has a center axis 101 which is also the rotation axis.

    [0023] A first collimator 610 having first optical fibers 611 at a first side of the rotary joint and opposing thereto at a second side of the rotary joint a second collimator 620 having second optical fibers 621 define an optical path. Light coming from first optical fibers is collimated by a first collimator such that a parallel beam of light preferably having a larger diameter than the core diameter of the optical fiber is generated. This beam of light is guided through the hollow shaft 300 and the Dove prism 500 located therein. Here, for simplicity the term of a Dove prism is used. Of course, any other prism suitable for derotation or any other derotating element may be used. The beam of light is collected by the second collimator 620 and coupled into a second optical fiber 621. There may be one optical path from a first optical fiber to a second optical fiber or a plurality of optical paths from the plurality of first optical fibers to a plurality of second optical fibers. Basically, there may be any number of such optical paths. It is obvious that light may be coupled from the first side to the second side or vice versa from the second side to the first side. There may also be mixed directions of optical paths, like a first path from the first side to the second side and a second path from the second side to the first side.

    [0024] The first collimator 610 is mounted to a first housing section 210 and the second collimator 620 is mounted to a second housing section 220. The first section 210 and the second housing section 220 are separated by a gap in an axial direction. The gap holds the bevel gear 400. The housing sections are independently rotatable against each other around the center axis. The first housing section has in an axial direction a first inner side 211 and a first outer side 212. The second housing section has in an axial direction a second inner side 221 and a second outer side 222. The first inner side 211 of the first housing section 210 is oriented towards the second inner side 221 of the second housing section 220.

    [0025] The hollow shaft 300 is arranged essentially within the first housing section 210 and the second housing section 220. It is further aligned with the center axis 101. The hollow shaft 300 has a first end 310 which extends into the first housing section 210 and a second end 320 which extends into the second housing section 220. The first housing section is supported on the first end of the shaft by at least a first bearing 350, and the second housing section is supported on the second end of the shaft by at least a second bearing 360. The at least one first bearing comprises preferably two, three or four bearings, or most preferably two first ball bearings 351, 352.

    [0026] Preferably, a first outer ball bearing 351 is close to the first outer side 212 and a first inner ball bearing 352 is close to the first inner side 211, wherein the prism holder and/or the prism is between the first outer ball bearing 351 and the first inner ball bearing 352. Most preferably, the bearings 351, 352 are axially distant from the prism holder and/or the prism. This results in a comparatively high axial stability, further increasing coupling losses. As the bearings are axially distant from the prism, comparatively small and therefore precise bearings may be used, as the bearings must no more enclose the prism.

    [0027] The at least one second bearing comprises preferably two, three or four bearings, or most preferably two second ball bearings 361, 362.

    [0028] The hollow shaft further has a prism holder 330 between the first and the second end. The prism holder is further preferably located within the first housing section 210.

    [0029] The bevel gear 400 is located in the gap 230 between the first housing section 210 and the second housing section 220. The gear comprises at least three wheels. A first wheel 410 is at the first inner side 211 of first housing section 210. A second wheel 420 is at the second inner side 221 of the second housing section 220. At least one third wheel 430 is arranged such that it meshes with first wheel 410 and the second wheel 420. The first wheel 410 and the second wheel 420 are coaxial to the center axis 101 and oppose each other such that the first wheel opposes the second wheel. It is preferred, if the first wheel and the second wheel have the same size and most preferably they are identical to each other. The at least one third wheel 430 has an axis 450 which is oriented radially to the center axis. The axis 450 is fixedly attached to the hollow shaft 300 or is one part with the hollow shaft. It may be a bolt or a screw. Therefore, rotation of the housing sections against each other causing the first or second wheel to rotate will also cause the third wheel to rotate and to generate a rotation of the hollow shaft around the center axis. The rotational speed of the hollow shaft is precisely half the speed of the housing sections relative to each other. As can be seen here, the bevel gear is displaced in axial direction from the prism holder, such that the axis of the third wheel in connection with the hollow shaft is comparatively short and the third wheel is comparatively close to the hollow shaft. By this arrangement the outer diameter of the rotary joint is comparatively small. This also keeps the rotating masses and the radius of the rotating masses small, such that the rotary joint can easily follow quick accelerations. This further reduces forces to the rotary joint components and therefore maintains a longer lifetime keeping the high precision of the rotary joint. Tests have shown that this design provides a long term stable precision and therefore maintains lower transmission losses for longer periods of time. Furthermore, as due to the comparatively large length of the rotary joint, the bearings of the housing section, specifically the housing section within which the Dove prism is located, can have large distances which further ensures a large angular stability and therefore high precision of the rotary joint. The bevel gear may comprise a plurality of wheels. In this embodiment, two wheels opposing to each other are shown.

    [0030] The prism holder 330 holds the prism 500 within the hollow shaft 300. Of course, the prism may also be mounted directly into the hollow shaft, but a prism holder preferably allows some adjustment of the prism.

    [0031] In Figure 2, an outer view of the rotary joint with the first housing section 210 and the second housing section 220 is shown. There may be a cover 240 covering the gap and the bevel gear therein.

    [0032] In Figure 3, an outer view further indicating the center axis 110 and the rotations of the first housing section 210 as well as the rotation of the second housing section 220 is shown.

    [0033] Figure 4 shows the embodiment of the previous figure, but with removed cover 240. It shows the bevel gear which is a special bevel gear embodiment, called a crown gear. In a crown gear, the pitch cone angle is 90 degrees. Further details are explained in the next figure.

    [0034] Figure 5 shows details of the bevel gear (crown gear). The bevel gear 400 is located in the gap 230 between the first housing section 210 and the second housing section 220. The gear comprises at least three wheels. A first wheel 410 is at the first inner side 211 of first housing section 210. A second wheel 420 is at the second inner side 221 of the second housing section 220. At least one third wheel 430 is arranged such that it meshes with first wheel 410 and the second wheel 420. The first wheel 410 and the second wheel 420 are coaxial to the center axis 101 and oppose each other such that the first wheel opposes the second wheel. Here, if the first wheel and the second wheel have the same size and most preferably they are identical to each other. This figure shows two third wheels 430, one to the front and one opposing thereto, to the rear in the figure. Each third wheel 430 has an axis 450 which is oriented radially to the center axis.

    [0035] The axis 450 is fixedly attached to the hollow shaft 300 or is one part with the hollow shaft. It may be a bolt or a screw. Therefore, rotation of the housing sections against each other causing the first or second wheel to rotate will also cause the third wheel to rotate and to generate a rotation of the hollow shaft around the center axis.

    List of reference numerals



    [0036] 
    100
    optical rotary joint
    101
    center axis
    110
    rotation of first housing section
    120
    rotation of second housing section
    200
    housing
    210
    first housing section
    211
    first inner side
    212
    first outer side
    220
    second housing section
    221
    second inner side
    222
    second outer side
    230
    gap
    240
    cover
    300
    hollow shaft
    310
    first end
    320
    second end
    330
    prism holder
    350
    first bearing
    351, 352
    first ball bearings
    360
    second bearing
    361, 362
    second ball bearings
    400
    bevel gear
    410
    first wheel
    420
    second wheel
    430
    third wheels
    450
    axis of third wheels
    500
    prism
    610
    first collimator
    611
    first optical fibers
    620
    second collimator
    621
    second optical fibers



    Claims

    1. Optical rotary joint (100) comprising a housing (200), a hollow shaft (300), a bevel gear (400), a prism (500), and two collimators (610, 620) the rotary joint (100) having a center axis (101),
    the housing (200) comprising a first housing section (210) and a second housing section (220) separated by a gap (230) in an axial direction from each other,
    the first housing section (210) and the second housing section (220) being rotatable against each other and around the center axis (101),
    the first housing section (210) having in axial direction a first inner side (211) and a first outer side (212),
    the second housing section (220) having in axial direction a second inner side (221) and a second outer side (222),
    the first inner side (211) being oriented towards the second inner side (221),
    a first collimator (610) is arranged at the first outer side (212) and a second collimator (620) is arranged at the second outer side (222),
    the hollow shaft (300) being aligned with the center axis (101),
    the hollow shaft (300) having a first end (310) extending into the first housing section (210) and a second end (320) extending into the second housing section (220),
    the first end (310) of the hollow shaft (300) is support for at least a first bearing (350), the first bearing (350) further being support of the first housing section (210) and
    the second end (320) of the hollow shaft (300) is support for at least a second bearing (360), the second bearing (360) further being support of the second housing section (220),
    the hollow shaft (300) having a prism holder (330) between the first end (310) and the second end (320), the prism holder (330) is located within the first housing section (210),
    the bevel gear (400) being located in the gap (230) between the first housing section (210) and the second housing section (220),
    the bevel gear (400) comprising a first wheel (410), a second wheel (420) and at least one third wheel (430),
    the first wheel (410) being coaxial to the center axis (101) at the first inner side (211) of the first housing section (210),
    the second wheel (420) being coaxial to the center axis (101) and opposing to the first wheel (410) at the second inner side (221) of the second housing section (220) and having the same diameter as the first wheel (410), the at least one third wheel (430) being between the first wheel (410) and the second wheel (420) and in mesh with the first wheel (410) and the second wheel (420),
    the at least one third wheel (430) having an axis (450) oriented radially to the center axis (101) and being fixedly attached to or being one part with the hollow shaft (300), such that a rotation of the first housing section (210) against the second housing section (220) with a first angular speed results in a rotation of the hollow shaft (300) with half of the first angular speed,
    the bevel gear (400) being displaced in axial direction from the prism holder (330),
    the prism (500) being located in the prism holder (330) of the hollow shaft (300).
     
    2. Optical rotary joint (100) according to claim 1,
    characterized in, by
    the gear (400) being a crown gear.
     
    3. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the gear (400) comprising 2, 3 or 4 third wheels (430), preferably arranged equidistant around the hollow shaft (300).
     
    4. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the at least one third wheel (430) having a smaller diameter than the first wheel (410).
     
    5. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the at least one third wheel (430) having a friction bearing or plain bearing.
     
    6. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the housing (200) having a cylindrical shape.
     
    7. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the first housing section (210) having the same outer diameter as the second housing section (220).
     
    8. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the housing (200) further comprising a cover (240) on the gap (230).
     
    9. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the prism (500) being a dove prism or an Abbe-Koenig prism.
     
    10. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the prism holder (330) having a larger outer diameter than the outer diameter of the first end (310) and of the second end (320) of the hollow shaft (300).
     
    11. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    at least one of the first bearing (350) and second bearing (360) comprising a ball bearing.
     
    12. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the first bearing (350) and the second bearing (360) being displaced in axial direction from the prism holder (330).
     
    13. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    the inner diameter of the first bearing (350) and the inner diameter of the second bearing (360) being smaller than an outer diameter of the prism holder (330).
     
    14. Optical rotary joint (100) according to any one of the preceding claims, characterized in, by
    at least one bearing (350, 360) being at each side of the prism holder (330).
     


    Ansprüche

    1. Optischer Drehübertrager (100), umfassend ein Gehäuse (200), eine Hohlwelle (300), ein Kegelrad (400), ein Prisma (500) und zwei Kollimatoren (610, 620), wobei der Drehübertrager (100) eine Mittelachse (101) aufweist,
    das Gehäuse (200) einen ersten Gehäuseabschnitt (210) und einen zweiten Gehäuseabschnitt (220) umfasst, die durch einen Spalt (230) in axialer Richtung voneinander getrennt sind,
    der erste Gehäuseabschnitt (210) und der zweite Gehäuseabschnitt (220) gegeneinander und um die Mittelachse (101) drehbar sind,
    der erste Gehäuseabschnitt (210) in axialer Richtung eine erste Innenseite (211) und eine erste Außenseite (212) aufweist,
    der zweite Gehäuseabschnitt (220) in axialer Richtung eine zweite Innenseite (221) und eine zweite Außenseite (222) aufweist,
    die erste Innenseite (211) zur zweiten Innenseite (221) ausgerichtet ist,
    ein erster Kollimator (610) an der ersten Außenseite (212) angeordnet ist und ein zweiter Kollimator (620) an der zweiten Außenseite (222) angeordnet ist,
    die Hohlwelle (300) mit der Mittelachse (101) ausgerichtet ist,
    die Hohlwelle (300) ein erstes Ende (310) aufweist, das sich in den ersten Gehäuseabschnitt (210) erstreckt, und ein zweites Ende (320), das sich in den zweiten Gehäuseabschnitt (220) erstreckt,
    das erste Ende (310) der Hohlwelle (300) eine Abstützung für mindestens ein erstes Lager (350) ist, wobei das erste Lager eine Abstützung des ersten Gehäuseabschnitts (210) ist, und das zweite Ende (320) der Hohlwelle (300) eine Abstützung für mindestens ein zweites Lager (360) ist, wobei das zweite Lager eine Abstützung des zweiten Gehäuseabschnitts (220) ist,
    die Hohlwelle (300) einen Prismenhalter (330) zwischen dem ersten Ende (310) und dem zweiten Ende (320) aufweist, wobei der Prismenhalter (330) innerhalb des ersten Gehäuseabschnitts (210) angeordnet ist,
    das Kegelrad (400) in dem Spalt (230) zwischen dem ersten Gehäuseabschnitt (210) und dem zweiten Gehäuseabschnitt (220) angeordnet ist,
    das Kegelrad (400) ein erstes Rad (410), ein zweites Rad (420) und mindestens ein drittes Rad (430) umfasst,
    das erste Rad (410) koaxial zur Mittelachse (101) an der ersten Innenseite (211) des ersten Gehäuseabschnitt (210) ist,
    das zweite Rad (420) koaxial zur Mittelachse (101) und dem ersten Rad (410) an der zweiten Innenseite (221) des zweiten Gehäuseabschnitts (220) gegenüberliegt und denselben Durchmesser wie das erste Rad (410) aufweist,
    das mindestens eine dritte Rad (430) zwischen dem ersten Rad (410) und dem zweiten Rad (420) ist und mit dem ersten Rad (410) und dem zweiten Rad (420) in Eingriff steht, das mindestens eine dritte Rad (430) eine Achse (450) aufweist, die radial zur Mittelachse (101) ausgerichtet ist und fest an der Hohlwelle (300) befestigt ist oder einteilig mit der Hohlwelle (300) ist, so dass eine Drehung des ersten Gehäuseabschnitts (210) gegen den zweiten Gehäuseabschnitt (220) mit einer ersten Winkelgeschwindigkeit zu einer Drehung der Hohlwelle (300) mit der Hälfte der ersten Winkelgeschwindigkeit führt,
    das Kegelrad (400) in axialer Richtung von dem Prismenhalter (330) verschoben wird, das Prisma (500) im Prismenhalter (330) der Hohlwelle (300) angeordnet ist.
     
    2. Optischer Drehübertrager (100) nach Anspruch 1,
    dadurch gekennzeichnet, dass
    das Zahnrad (400) ein Kronenrad ist.
     
    3. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das Zahnrad (400) 2, 3 oder 4 dritte Räder (430) umfasst, welche vorzugsweise äquidistant um die Hohlwelle (300) angeordnet sind.
     
    4. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass
    das mindestens eine dritte Rad (430) einen kleineren Durchmesser als das erste Rad (410) hat.
     
    5. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das mindestens eine dritte Rad (430) ein Gleitlager aufweist.
     
    6. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das Gehäuse (200) eine zylindrische Form hat.
     
    7. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    der erste Gehäuseabschnitt (210) den gleichen Außendurchmesser wie der zweite Gehäuseabschnitt (220) aufweist.
     
    8. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das Gehäuse (200) weiterhin eine Abdeckung (240) auf dem Spalt (230) umfasst.
     
    9. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das Prisma (500) ein Dove-Prisma oder ein Abbe-Koenig-Prisma ist.
     
    10. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    der Prismenhalter (330) einen größeren Außendurchmesser als der Außendurchmesser des ersten Endes (310) und des zweiten Endes (320) der Hohlwelle (300) aufweist.
     
    11. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass
    mindestens eines von dem ersten Lager (350) und dem zweiten Lager (360) ein Kugellager umfasst.
     
    12. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    das erste Lager (350) und das zweite Lager (360) in axialer Richtung vom Prismenhalter (330) versetzt sind.
     
    13. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    der Innendurchmesser des ersten Lagers (350) und der Innendurchmesser des zweiten Lagers (360) kleiner sind als ein Außendurchmesser des Prismenhalters (330).
     
    14. Optischer Drehübertrager (100) nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, dass
    mindestens ein Lager (350, 360) auf jeder Seite des Prismenhalters (330) ist.
     


    Revendications

    1. Joint optique tournant (100) comprenant un logement (200), une tige creuse (300), un engrenage conique (400), un prisme (500), et deux collimateurs (610, 620)
    le joint tournant (100) ayant un axe central (101), le logement (200) comprenant une première section de logement (210) et une seconde section de logement (220) séparées l'une de l'autre par un écartement (230) dans une direction axiale,
    la première section de logement (210) et la seconde section de logement (220) pouvant tourner l'une contre l'autre et autour de l'axe central (101),
    la première section de logement (210) ayant en direction axiale un premier côté intérieur (211) et un premier côté extérieur (212),
    la seconde section de logement (220) ayant en direction axiale un second côté intérieur (221) et un second côté extérieur (222),
    le premier côté intérieur (211) étant orienté vers le second côté intérieur (221),
    un premier collimateur (610) est agencé au niveau du premier côté extérieur (212) et un second collimateur (620) est agencé au niveau du second côté extérieur (222),
    la tige creuse (300) étant alignée avec l'axe central (101),
    la tige creuse (300) ayant une première extrémité (310) s'étendant dans la première section de logement (210) et une seconde extrémité (320) s'étendant dans la seconde section de logement (220),
    la première extrémité (310) de la tige creuse (300) est un support pour au moins un premier palier (350) qui est en outre un support de la première section de logement (210) et la seconde extrémité (320) de la tige creuse (300) est un support pour au moins un second palier (360) qui est en outre un support de la seconde section de logement (220),
    la tige creuse (300) ayant un porte-prisme (330) entre la première extrémité (310) et la seconde extrémité (320), le porte-prisme (330) est situé au sein de la première section de logement (210),
    l'engrenage conique (400) étant situé dans l'écartement (230) entre la première section de logement (210) et la seconde section de logement (220),
    l'engrenage conique (400) comprenant une première roue (410), une deuxième roue (420) et au moins une troisième roue (430),
    la première roue (410) étant coaxiale à l'axe central (101) au niveau du premier côté intérieur (211) de la première section de logement (210),
    la deuxième roue (420) étant coaxiale à l'axe central (101) et opposée à la première roue (410) au niveau du second côté intérieur (221) de la seconde section de logement (220) et ayant le même diamètre que la première roue (410),
    l'au moins une troisième roue (430) étant entre la première roue (410) et la deuxième roue (420) et engrenée avec la première roue (410) et la deuxième roue (420),
    l'au moins une troisième roue (430) ayant un axe (450) orienté radialement par rapport à l'axe central (101) et étant fixé à demeure à la tige creuse (300) ou faisant partie de celle-ci, de sorte qu'une rotation de la première section de logement (210) contre la seconde section de logement (220) à une première vitesse angulaire se traduit par une rotation de la tige creuse (300) à la moitié de la première vitesse angulaire,
    l'engrenage conique (400) étant déplacé en direction axiale par rapport au porte-prisme (330),
    le prisme (500) étant situé dans le porte-prisme (330) de la tige creuse (300).
     
    2. Joint optique tournant (100) selon la revendication 1,
    caractérisé en ce que
    l'engrenage (400) est une couronne.
     
    3. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    l'engrenage (400) comprend 2, 3 ou 4 troisièmes roues (430), agencées de préférence équidistantes autour de la tige creuse (300).
     
    4. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    l'au moins une troisième roue (430) a un diamètre plus petit que la première roue (410).
     
    5. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    l'au moins une troisième roue (430) a un palier à friction ou un palier lisse.
     
    6. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le logement (200) a une forme cylindrique.
     
    7. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    la première section de logement (210) a le même diamètre extérieur que la seconde section de logement (220).
     
    8. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le logement (200) comprend en outre un couvercle (240) sur l'écartement (230).
     
    9. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le prisme (500) est un prisme de Dove ou un prisme d'Abbe-Koenig.
     
    10. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le porte-prisme (330) a un diamètre extérieur plus grand que le diamètre extérieur de la première extrémité (310) et de la seconde extrémité (320) de la tige creuse (300).
     
    11. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    au moins l'un du premier palier (350) et du second palier (360) comprend un palier à billes.
     
    12. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le premier palier (350) et le second palier (360) sont déplacés en direction axiale par rapport au porte-prisme (330).
     
    13. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    le diamètre intérieur du premier palier (350) et le diamètre intérieur du second palier (360) sont plus petits qu'un diamètre extérieur du porte-prisme (330).
     
    14. Joint optique tournant (100) selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    au moins un palier (350, 360) est au niveau de chaque côté du porte-prisme (330).
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description