US3878395A - Method and means for operating x-ray tubes with rotary anodes - Google Patents

Method and means for operating x-ray tubes with rotary anodes Download PDF

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Publication number
US3878395A
US3878395A US423665A US42366573A US3878395A US 3878395 A US3878395 A US 3878395A US 423665 A US423665 A US 423665A US 42366573 A US42366573 A US 42366573A US 3878395 A US3878395 A US 3878395A
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United States
Prior art keywords
anode
rotary
ray tube
support
magnetic
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Expired - Lifetime
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US423665A
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English (en)
Inventor
Gerd Seifert
Gunther Appelt
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Siemens AG
Siemens Corp
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Siemens Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0402—Bearings not otherwise provided for using magnetic or electric supporting means combined with other supporting means, e.g. hybrid bearings with both magnetic and fluid supporting means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • H01J35/101—Arrangements for rotating anodes, e.g. supporting means, means for greasing, means for sealing the axle or means for shielding or protecting the driving
    • H01J35/1017—Bearings for rotating anodes
    • H01J35/103—Magnetic bearings

Definitions

  • the present invention is based on the consideration that when X-ray tubes with rotary anodes are operated, it is desirable to make spontaneous photographs without having to take into consideration disturbing or detrimental factors, such as, for example, the starting time, noises and wear of the bearings.
  • an object of the present invention is the provision of a method by the use of which, within the usual operational conditions, it is possible to have X-ray photographing devices with rotary anodes which are ready for photographing at any time, while providing sufficient stability for the tube.
  • a process of the present invention for operating X-ray tubes with rotary anodes and accomplishing this object of the present invention consists in that the anode is caused to rotate and continues in rotation when and so long as there .is a possibility of an X-ray photograph being taken and that the anode is magnetically supported without contact, with the exception of a preferably axial bearing transmitting the tube current.
  • the present invention provides a rotary anode that can run for long working periods, namely, for an entire working day or even longer, without the bearing wearing out. Besides elimination of noises, the tube is held in continuous 'working readiness for photographing. Photographs can also be made at unpredetermined moments, which can be of great importance for diagnosis. It is no longer necessary to wait for the end of the starting time of the anode. Furthermore, it is necessary to apply the starting energy to the anode only once during a working period, and it is no longer necessary to apply brakes to very quickly running anodes to avoid wear and noises. In addition, it is possible to make the anodes run faster, so that the speed of rotation can be adapted to the load without having to consider the wear of the bearing. Due to magnetic support, there is no contact of moving parts with the immovable parts, with the exception of one connection through which flows the current of the X-ray tube, such as an axial bearing.
  • Magnetic bearings are known in the art and are described, for example, in the publication Philips Technische Rundschau, 1960/61, No. 7, pages 252 to 259.
  • electromagnets are difficult to insert into a rotor since they require conduits. A feeding current must be supplied through slides. This again produces friction and wear which must be avoided. This is also one of the difficulties for insertion of a motor into the vacuum space of the tube.
  • magnetic spools built into the rotor could receive current from induction spools also fixed to the rotor.
  • field forces resulting from such an energy transmission would act upon the rotor, and this is not desired, since the forces must be taken from the magnetic bearing and they would increase requirements made upon the magnetic bearing.
  • a bearing then consists of two coaxially arranged tubular piles consisting of superposed electromagnetic rings which are alternately opposedly magnetized.
  • One of the piles, consisting of so-called inner magnets has a small diameter, and is located within the other pile having so-called outer magnets with a large diameter.
  • Direct current flows through ring-shaped field windings of all inner and outer magnets to produce a magnetic field.
  • soft magnetic rings are located upon its inner side. They are yokes of inner magnets consisting of the same material, but without touching them.
  • the radial width of the overlapping is such that the poles of the inner magnets extend outwardly, even if there is some excentricity of the rotor relatively to the ringshaped magnets, over the soft magnetic rings, i.e., yokes. of the rotor.
  • the ring-shaped outer magnets can exert repelling forces upon the rotor without it being necessary to apply magnets to the rotor itself. For this. reason, electromagnets can also be used without it being necessaryy to have slide contacts.
  • the distance between the inner edges of the yokes of the outer magnets and the outer edges of the yoke rings of the rotor, which can be indicated by the letter 0, should be small so that the force (which is opposed to the eccentricity of the rotor) has the highest possible value, and the axial height ofa magnetic ring should be above three times greater than the distance c, according to statements of best results indicated in the abovestated publication.
  • the distance c is fixed by the tension strength of this stretch and is comparatively large to 12 mm.) However, it can also be small, and is determined solely by manufacturing tolerances and the wall strength of the vacuum piston when the outer magnets follow the rotor in their potential.
  • the yoke rings carried by the rotor overlap the inner magnets without touching them. This overlapping can be provided by segmenting the yoke rings provided in the rotor.
  • the rotor consists advantageously in the section pertaining to the magnetic bearing out of a non-magnetic outer cylinder and a non-magnetic inner cylinder which is rotationally safely fixed with tight fit in the outer cylinder and which carries yoke rings of the rotor fixed in grooves, possibly soldered.
  • the inner cylinder and the yoke rings fixed thereon are cut into two halves in a plane extending through the rotor axis.
  • the inner cylinder with the yoke rings separates into two equal segments as soon as it is removed from the outer cylinder. These segments can then be placed about the inner magnets and then held together by positioning the outer cylinder.
  • the axially directed attracting forces which each inner magnet exerts upon two yoke rings of the rotor are balanced by themselves due to the arrangement of the rotor yoke rings in pairs in the rotor, provided that the two air gaps between the inner magnet and the two corresponding yoke rings of the rotor are equal in size.
  • outer and inner magnets makes possible a damping in the return movement in that high return forces are operative only until a sufficient differential decrease of eccentricity with the time de/dt is reached, so that the rotor will not carry any regulating swingings or only small ones about its central location.
  • the operation of the magnets is thus dependent upon a signal which is directly connected with the eccentricity of the moment.
  • This signal can be produced by placing two metal cylinders coaxially about the rotor without touching the outer magnets, and the capacity between these two cylinders acts more or less out of time upon a swinging circuit and thus upon the oscillation amplitude of this swinging circuit.
  • the capacity between these two cylinders is then dependent upon the eccentricity, since the electrical fields are formed from one of the two cylinders to the other cylinder substantially over the rotor.
  • the oscillation amplitude of the resonance circuit can actuate currents in the -field windings of the magnets through an electronic regulating stretch, the characteristic of which is adapted to the top motion conditions of the rotor.
  • FlG. l is a sectional side view of an X-ray tube with rotary anode, suitable for the purposes of the present invention.
  • FIG. 2 is a transverse section along the line "-11 of FIG. 1.
  • FIGS. 3 and 4 are sections through two different constructions of magnetic bearings.
  • FIG. 1 shows a vacuum container 1 having at one end the cathode arrangement 2 and at the other end the anode combination 3.
  • the actual glow cathode 4 is fixed by a support 5 in an innerly directed tube 6 of the glass container 1.
  • a support 8 is melted into the side of the vacuum container 1 located opposite the tube 6.
  • the bearing S carries ring-Shaped field windings of electromagnets indicated by numerals 9 to 15.
  • the field windings 9 to 15 are amplified into ring-shaped inner magnets by the yokes 16 to 23 of soft magnetic material as well as the soft magnetic support 8.
  • F urthermore a plate disc 7 is placed vacuum-tightly in the support 8 by a more or less strong tensioning.
  • This plate holds a point bearing 24, which is slightly shiftable in axial direction.
  • the anode combination 3 is held in axial direction in electrical contact with the member 7 through the point of the carrying spindle 24 located in the bearing 24.
  • the rotor 27 is provided at the upper part of the axle 25, constructed as a spindle close to the anode plate 26.
  • the rotor consists of two non-magnetic hollow cylinders stuck one within the other, and carries upon its inner side yokes 28 to 35 of soft magnetic iron. These yokes are magnetically in engagement with yokes 16 to 23 of electromagnets with the field windings 9 to 15.
  • the yokes 28 to 35 extend further outwardly the fields of the windings 9 to 15.
  • the fields of the windings 36 to 42 as locate'dat the outer side of the tube container 1, are arranged precisely in space above the yoke rings 43 to 50 fixed upon the soft magnetic cylinder 71.
  • a stator 52 is arranged in the known manner on the outer side of the container 1 at the rotor end distanced from the rotary anode plate 26 and the actual driving part 51 of the rotor 27.
  • a potential cylinder 72 is provided to keep smallthe space between the yokes 43 to 50 and the vacuum container 1 without causing improperly high electrical field strength at the inner edges of the yokes 43 to 50 (due to high voltage which the anode 3 provides during X-ray photographing relative to ground, thus also relative to outer magnets located at the ground potential).
  • the functioning of the present invention in the illustrated example takes place in that a current is switched on which is received from the source through conduits 73, 74 and 75 into the switch device 55 and throughthe conduits 56 and 57, and the insulation stretch with secondary rectification 76 is directly transmitted to field windings 9 to and through conduits 77 and 78 to the field windings 36 to 42.
  • a support of the rotary parts of the anode 3 in the radial direction is produced without contact. This is based on the repelling forces of the magnetic fields emanating from the windings 36 to 42 and acting upon yokes 28 to 35 magnetized by field windings 9 to 15.
  • the capacity between the probe 60 and the potential cylinder 72 is measured from the device 55 through conduits 58 and 59.
  • the device 55 also contains means operating the currents in the conduits 56 and 57, resp. 77 and 78, depending upon the extent of eccentricity and the extent of change of eccentricity in time.
  • the eccentricity or the change of eccentricity in time causes the device 55 to transmit such currents through the conduits 56 and 57 and the conduits 77 and 78 and thus through the field windings of magnets within and outsideof the rotor, that forces are exerted upon the rotor which are opposed to eccentricity, but which act against the eccentricity only to the extent that the rotor will not carry out regulating swingings about its central position.
  • X-rays are produced in the known manner, on the one hand, by supplying current necessary for sending electrons through the conduits 61 and 62 of the glow cathode 4, and on the other hand, by applying high voltage 65 of a few 10 v. produced by the generator 64 located at the net 73, 74 and 75 between the glow cathode 4 and the conduit 63, which is in galvanic contact with the rotary anode 26.
  • the electrons emitted by the glow cathode are transmitted by the stator 52 relative to the alternating current of the generator 64 or two-phase alternating current 66 over conduits 67, 68, and 69; they are accelerated by the rotating anode 26, and their kinetic energy is transformed there in a known manner into X-rays which leave the tube as a cone-shaped bundle 70.
  • FIG. 2 shows the arrangement of the field windings 13 and 40 as well as those of the interengaging yokes and 32 and of the yoke 47 located in one plane in the yoke 32.
  • the wall of the vacuum container 1 is visible between the yoke 32 and the yoke 47.
  • the outer yoke rings 43 to 50 are fixed to the magnetically soft cylinder 71, and the inner yoke rings 16 to 23 are fixed to the soft-magnetic support 8.
  • the spindle moves in the center of thehollow support 8.
  • FIG. 3 shows the driving part 51' of the rotor 27' and the stator 52 arranged upon the end of the staple of magnets directed to the rotary anode plate 26.
  • the distance of the staples 79 and 80 from the rotary anode plate 26' is greater than the distance of the rotary anode plate from the magnetic staples according to the construction of FIG. 1. This is of particular advantage when the rotary anode is to be very heavily loaded. Due to the increased space, the passage of heat is also longer, and the magnetic staple 79 as well as the staple will be subjected only to low temperatures.
  • the inner staple 79 acts repellently upon the yokes 81 and 82, located at the rotor 27
  • the yokes 84, 84 and 85 belong to the outer staple 86, which, due to the necessarily smaller air gap between the yokes of the rotor and those of the outer magnets, must lie upon the anode potential.
  • the yokes 83, 84 and 85 extend through the wall 86 of the container l-of the tube.
  • the driving member 51" and the stator 52" are arranged in the middle of the length of the carrying spindle 25". Due to this arrangement, the two magnetic staples are divided into two parts; namely, two separate supports are produced. Thus, for inner magnets are produced partial staples 88 and 89, which are held at a distance from each other by a distancing holder 90 corresponding to the length of the driving member 51". The outer magnet is also divided into staples 91 and 92, which are counterparts of the staple parts 88 and 89.
  • amechanical separation is provided between the inner staples 88 and 89 and their coordinated rotor yokes 93, 94 and 95, 96, and also between staples 91 and 92 and their yokes 83' to 97 and 98.
  • the space 87 is the same as the space 87 of FIG. 3. Only the wall 99 of the container 1" consists of glass and is not penetrated by the yokes 83 to 85, 97 and 98, but on the inner side of the wall 94, there is a holding coating 100 which holds the yokes 83 to 85, 97 and 98.
  • This construction in addition to deviating from the constructive structure of the yokes and the magnetic staples, has the advantage that the magnetic supports can have the greatest possible distance from each other in the manner usual for ball bearings at a predetermined length of the axle 25". In this construction, a stable support is produced while accepting heating in staple 88 greater than in construction of FIG. 3.
  • the length of the axle 25 (FIG. 1) is so selected that the imaginary vertical line 101 upon the focal point path 102 of the anode 26 cuts in the contact point of theaxial bearing 24. This can be the supporting point of the pointed end of the axle 25 constructed as a spindle.
  • a similar axial support is provided by a ball 104 (FIG. 4) located between the end of the axle 25" having a flat or concave shape and the counter bearing 105, namely, the inner wall of the connecting member 106.
  • a process for operating rotary anodes of X-ray tubes comprising magnetically supporting the anode free from contact except for a support transmitting the X-ray current and rotating the anode continuously during the entire period in which there is a possibility that an X-ray photograph will be taken.
  • a rotary anode X-ray tube provided with a mechanical bearing means for giving mechanical support to the rotary anode when it is rotating in its operative disposition and serving to conduct tube current passing by way of the anode, and magnetic bearing means adapted to give additional support to the anode magnetically when it is so rotating thereby enabling the anode to remain in the said operative disposition, while rotating, without further mechanical support, said magnetic bearing means being arranged to give the anode radial support relative to its rotary axis. and said mechanical bearing means being arranged to give the anode axial support.
  • an X-ray tube as claimed-in claim 3 wherein the said magnetic bearing means comprises afirst stack of aligned annular electromagnet coils which extend,'lo'ngitudinally of the rotary axis of the anode, along and within a second stack of such coils, said first stack being located radially inwards of a rotary part of the anode that is surrounded by the said second stack in an internal space bounded by the said rotary part, alternate coils in each of the stacks being adapted to produce mutually opposed magnetic fields when energized in a predetermined manner, and the said rotary part having magnetically conductive portions arranged to extend. with clearance, between said first and second stacks so that magnetic forces exerted on the said rotary parts by the stacks when the coils thereof are energized hold the anode in its operative disposition when rotating.
  • An X-ray tube as claimed in claim 5 wherein the said magnetically conductive portions are arranged so as to rotate, when'the anode is rotating in its operative disposition, freely past respective further magnetically conductive portions that are mounted radially inwards of the said rotary part and serve as magnetic yokes for the said first stack.
  • an X-ray tube as claimed in claim S Wherein the anode has arranged axially between an anode plate thereof and that end of the said stacks nearer to'the anode plate a drive part with which a stator winding extending freely aroundthe drive part is adapted to cooperate to cause rotation of the anode when the stator winding is energized in a predetermined manner.
  • An X-ray tube as claimed in claim 5 wherein said stacks are divided into two parts which are separated from one. another, axially of the anode, by a drive part thereof which is surrounded by a stator winding which is adapted to cooperate with the drive part so as to cause rotation of the anode when the stator winding is energized in a predetermined manner.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • X-Ray Techniques (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
US423665A 1972-12-21 1973-12-11 Method and means for operating x-ray tubes with rotary anodes Expired - Lifetime US3878395A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2262757A DE2262757C3 (de) 1972-12-21 1972-12-21 RöntgenrShrendrehanodenlagerung

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US (1) US3878395A (enrdf_load_stackoverflow)
CH (1) CH570699A5 (enrdf_load_stackoverflow)
DE (1) DE2262757C3 (enrdf_load_stackoverflow)
FR (1) FR2211749B1 (enrdf_load_stackoverflow)
GB (1) GB1438317A (enrdf_load_stackoverflow)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4167671A (en) * 1977-04-12 1979-09-11 Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung Rotary anode X-ray tube
DE3004531A1 (de) * 1980-02-07 1981-08-13 Siemens AG, 1000 Berlin und 8000 München Drehanoden-roentgenroehre
US4322624A (en) * 1979-03-30 1982-03-30 U.S. Philips Corporation X-ray tube having a magnetically supported rotary anode
FR2494497A1 (fr) * 1980-11-19 1982-05-21 Siemens Ag Tube a rayons x a anode tournante
US4357555A (en) * 1979-05-08 1982-11-02 U.S. Philips Corporation Rotary anode X-ray tube
EP0082249A1 (de) * 1981-12-16 1983-06-29 Siemens Aktiengesellschaft Drehanoden-Röntgenröhren
US4417171A (en) * 1980-11-14 1983-11-22 Siemens Aktiengesellschaft Rotary anode x-ray tube
FR2532782A1 (fr) * 1982-09-06 1984-03-09 Siemens Ag Tube a rayons x et a anode tournante
US4468801A (en) * 1981-07-30 1984-08-28 Tokyo Shibaura Denki Kabushiki Kaisha Rotary anode X-ray tube
US4583794A (en) * 1984-02-03 1986-04-22 Kabushiki Kaisha Toshiba Electromagnetic bearing
US4651336A (en) * 1983-05-06 1987-03-17 Thomson-Csf Rotating-anode X-ray tube
US4677651A (en) * 1983-12-05 1987-06-30 U.S. Philips Corporation Rotary anode X-ray tube having a sliding bearing
US4780900A (en) * 1985-05-07 1988-10-25 Thomson-Cgr Radiogenic tube radiological device with magnetic bearings
US4920551A (en) * 1985-09-30 1990-04-24 Kabushiki Kaisha Toshiba Rotating anode X-ray tube
EP1081740A1 (de) * 1999-07-07 2001-03-07 Philips Corporate Intellectual Property GmbH Drehanoden-Röntgenröhre mit axialer Lagerung.
US20150117604A1 (en) * 2012-05-22 2015-04-30 Koninklijke Philips N.V. Balancing in an x-ray tube
JP2021528831A (ja) * 2018-09-28 2021-10-21 ヴァレックス イメージング コーポレイション 磁気アシストベアリングの真空浸透

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2601529C2 (de) * 1976-01-16 1982-04-29 Philips Patentverwaltung Gmbh, 2000 Hamburg Magnetische Lagerung der Drehwelle der Drehanode für eine Röntgenröhre
DE3000357C2 (de) * 1980-01-07 1982-12-30 Arthur Pfeiffer Vakuumtechnik Wetzlar Gmbh, 6334 Asslar Mechanisches Hilfslager für magnetische Lagerung

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3502926A (en) * 1967-03-24 1970-03-24 Hitachi Ltd Rotating anode x-ray tube with magnetic damper

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7307042A (enrdf_load_stackoverflow) * 1973-05-21 1974-11-25

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3502926A (en) * 1967-03-24 1970-03-24 Hitachi Ltd Rotating anode x-ray tube with magnetic damper

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4167671A (en) * 1977-04-12 1979-09-11 Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung Rotary anode X-ray tube
US4322624A (en) * 1979-03-30 1982-03-30 U.S. Philips Corporation X-ray tube having a magnetically supported rotary anode
US4357555A (en) * 1979-05-08 1982-11-02 U.S. Philips Corporation Rotary anode X-ray tube
DE3004531A1 (de) * 1980-02-07 1981-08-13 Siemens AG, 1000 Berlin und 8000 München Drehanoden-roentgenroehre
US4417171A (en) * 1980-11-14 1983-11-22 Siemens Aktiengesellschaft Rotary anode x-ray tube
FR2494497A1 (fr) * 1980-11-19 1982-05-21 Siemens Ag Tube a rayons x a anode tournante
US4414681A (en) * 1980-11-19 1983-11-08 Siemens Aktiengesellschaft Rotary anode x-ray tube
US4468801A (en) * 1981-07-30 1984-08-28 Tokyo Shibaura Denki Kabushiki Kaisha Rotary anode X-ray tube
US4504965A (en) * 1981-12-16 1985-03-12 Siemens Aktiengesellschaft Rotary anode X-ray tubes
EP0082249A1 (de) * 1981-12-16 1983-06-29 Siemens Aktiengesellschaft Drehanoden-Röntgenröhren
FR2532782A1 (fr) * 1982-09-06 1984-03-09 Siemens Ag Tube a rayons x et a anode tournante
US4651336A (en) * 1983-05-06 1987-03-17 Thomson-Csf Rotating-anode X-ray tube
US4677651A (en) * 1983-12-05 1987-06-30 U.S. Philips Corporation Rotary anode X-ray tube having a sliding bearing
US4583794A (en) * 1984-02-03 1986-04-22 Kabushiki Kaisha Toshiba Electromagnetic bearing
US4780900A (en) * 1985-05-07 1988-10-25 Thomson-Cgr Radiogenic tube radiological device with magnetic bearings
US4920551A (en) * 1985-09-30 1990-04-24 Kabushiki Kaisha Toshiba Rotating anode X-ray tube
EP1081740A1 (de) * 1999-07-07 2001-03-07 Philips Corporate Intellectual Property GmbH Drehanoden-Röntgenröhre mit axialer Lagerung.
US20150117604A1 (en) * 2012-05-22 2015-04-30 Koninklijke Philips N.V. Balancing in an x-ray tube
JP2021528831A (ja) * 2018-09-28 2021-10-21 ヴァレックス イメージング コーポレイション 磁気アシストベアリングの真空浸透

Also Published As

Publication number Publication date
DE2262757A1 (de) 1974-06-27
FR2211749B1 (enrdf_load_stackoverflow) 1978-02-10
DE2262757C3 (de) 1979-06-21
CH570699A5 (enrdf_load_stackoverflow) 1975-12-15
FR2211749A1 (enrdf_load_stackoverflow) 1974-07-19
GB1438317A (en) 1976-06-03
DE2262757B2 (de) 1978-10-26

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