EP0373705B1 - Rotating anode X-ray tube with a liquid lubricant - Google Patents
Rotating anode X-ray tube with a liquid lubricant Download PDFInfo
- Publication number
- EP0373705B1 EP0373705B1 EP89203122A EP89203122A EP0373705B1 EP 0373705 B1 EP0373705 B1 EP 0373705B1 EP 89203122 A EP89203122 A EP 89203122A EP 89203122 A EP89203122 A EP 89203122A EP 0373705 B1 EP0373705 B1 EP 0373705B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- lubricant
- ray tube
- anode
- rotary
- bearing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- 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
- H01J35/104—Fluid bearings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/10—Drive means for anode (target) substrate
- H01J2235/1046—Bearings and bearing contact surfaces
- H01J2235/106—Dynamic pressure bearings, e.g. helical groove type
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/10—Drive means for anode (target) substrate
- H01J2235/1046—Bearings and bearing contact surfaces
- H01J2235/1066—Treated contact surfaces, e.g. coatings
Definitions
- the invention relates to a rotating anode X-ray tube with at least one slide bearing which is filled with a liquid lubricant.
- a rotating anode X-ray tube with at least one slide bearing which is filled with a liquid lubricant.
- Such an X-ray tube is among others known from EP-A-0 141 476.
- the slide bearings for mounting the rotating anode are formed by so-called spiral groove bearings, which have a narrow gap and a pattern of grooves on one of their bearing surfaces.
- the lubricant is located in the bearing gap, which is delimited on one side by a smooth bearing surface and on the other side by the surface with the groove pattern.
- the grooves are shaped so that the lubricant remains in the bearing during operation of the rotating anode X-ray tube with a predetermined direction of rotation.
- the spiral groove bearing is adjoined by a surface which is prepared in such a way that it cannot be wetted by the lubricant, e.g
- the surfaces in the opening area, via which the spiral groove bearing is connected to the rest of the vacuum space of the X-ray tube consist of a material which can be wetted by the lubricant and can thus form mixed phases or alloys.
- the surface of the opening area, through which the lubricant has to pass in order to get out of the bearing into the remaining vacuum space which is filled with an electric field in the operating state consists of a material which can be wetted by the lubricant and thus forms mixed phases.
- the lubricant can therefore not escape into the space filled with an electric field in the operating state, because it adheres to the surface in the opening area and diffuses into it.
- the area up to the high-voltage vacuum space should be designed as a labyrinth if possible.
- gallium alloys are suitable as lubricants for slide bearings in X-ray tubes. These alloys form a mixed phase with many metals, ie a new alloy, but often only when the surfaces of the metals passivated by oxides or carbides have been destroyed. Only metals that do not form such boundary layers (noble metals) or in which these boundary layers are destroyed by the pumping and heating processes associated with the conditioning of X-ray tubes, for example copper, are therefore suitable.
- the lubricant is made of a gallium alloy and the surface in the opening area consists of a precious metal. A drop of lubricant made of a gallium alloy spreads on an eg gold-plated metal surface due to the wetting and alloying and diffuses into the base material, especially at elevated temperatures, but also at room temperature.
- the surfaces provided according to the invention which are wettable by the lubricant and thus form mixed phases, directly adjoin the slide bearing surfaces, the lubricant would pass relatively easily from the slide bearing to these surfaces, which would result in an undesirable loss of lubricant.
- This can be reduced in a further embodiment of the invention in that the surfaces immediately adjacent to the spiral groove bearing consist of a material that is not wettable by the lubricant and that the surfaces wettable by the lubricant and thus forming mixed phases are connected.
- non-wettable surfaces can be e.g. Titanium oxide carbide coatings or silicon oxide carbide coatings are generated.
- the X-ray tube shown in the drawing has a metal piston 1, in which a radiation exit window 2, for example made of beryllium, is provided and which carries the cathode 4 on a first insulator 3 and the rotating anode 6 on a second insulator 5.
- the rotating anode 6 comprises an anode disk 7, of which the X-ray radiation during operation goes out, and which is connected to the second insulator 5 via a bearing.
- the fixed part of the bearing comprises an axis 8 made of a molybdenum alloy, which is connected to the insulator 5 via a carrier body 9 made of an iron-nickel-cobalt alloy (Vacon).
- the positive high voltage for the rotating anode is supplied via part 9.
- the rotating part 10 of the bearing 6 comprises a bearing bush 10 which is concentric with the axis 8 and which likewise consists of a molybdenum alloy and is adapted to the dimensions of the axis 8, so that only a narrow gap remains between the axis 8 and the bush 10, which gap is considerably narrower is shown as in the drawing and is eg 20 »m thick.
- the bearing is a plain bearing in the form of a spiral groove bearing.
- the axis 8 is provided with two herringbone groove patterns 12 which are offset from one another in the axial direction and act as radial bearings.
- the axis 8 also contains a cylindrical thickening 13, the end faces of which are also provided with a groove pattern, not shown, and therefore act as a spiral groove bearing for the axial mounting of the anode 6. Because of the thickening 13, the bushing 10 cannot be in one piece - as shown in the drawing - but must consist of at least two parts which are connected to one another in such a way that the lubricant cannot escape through the connection areas.
- a gallium alloy (GaInSn) is located as a lubricant 14 in the space between the axis 8 and the bushing 10. This lubricant is liquid at room temperature and wets the surfaces of the axis 8 and the bushing 10 without entering into alloys.
- the surfaces in the opening area through which the lubricant emerging from the bearing passes into the remaining vacuum space of the X-ray tube are gold-plated. This is indicated by thick solid lines 15 on the outer surface of the carrier body 9 and the surface of the bushing 10 facing it and the inner surface of the rotor 11.
- the gallium alloy that forms the lubricant wets gold-plated metal surfaces and thus forms a new alloy at room temperature. A drop of lubricant therefore adheres to these metal surfaces in the field-free area and cannot escape into the vacuum space of the X-ray tube that is filled by the field.
- the surfaces in the opening area are advantageously arranged like a labyrinth.
- the surface in the opening area must be such that it can be easily wetted by the lubricant and forms an alloy with it.
- this includes precious metals - including gold - but also other metals.
- the surface of the non-precious metals is mostly passivated by oxides or carbides, so that a drop of gallium is not on it sticks.
- these metals e.g. copper
- these layers are largely destroyed by the pumping and baking processes, which an X-ray tube must be subjected to before the first start-up. Wetting occurs on an approx. 100 ° C hot copper surface and thus traps a lubricant drop.
- the gold plating of the inner surface of the copper rotor 11 could therefore be omitted provided that the copper surface is not contaminated and is kept at at least 100 ° C.
- This carrier body also gradually absorbs the leaked lubricant, which has the particular advantage that the expensive gold layer can be very thin. If this carrier body came into contact with the lubricant without gold plating, the oxide or carbide boundary layers on the surface would prevent the lubricant from sticking.
- the gold layer must be anchored to the carrier body in such a way that the disruptive boundary layers are destroyed, e.g. through known galvanic preparation methods.
- the surfaces wettable by the lubricant - and this also includes the surfaces of the bearing bush 10 and the axis 8 in the lower region - would reach right up to the slide bearings, then the lubricant could wet these surfaces relatively easily and would be removed from the bearing.
- the surfaces are in the lower area of axis 8 and of the bearing 10, as indicated by the dotted lines, provided with a layer which prevents wetting by the lubricant.
- a suitable layer consists, for example, of titanium oxide carbide. It prevents lubricant from running out of the bearing during normal operation. It is only when the lubricant has overcome this non-wettable, capillary-effective area through strong mechanical impacts or the like that it hits the layer according to the invention, to which it adheres.
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- Sliding-Contact Bearings (AREA)
Description
Die Erfindung betrifft eine Drehanoden-Röntgenröhre mit mindestens einem Gleitlager, das mit einem flüssigen Schmiermittel gefüllt ist. Eine solche Röntgenröhre ist u.a. aus der EP-A-0 141 476 bekannt. Die Gleitlager zur Lagerung der Drehanode werden dabei durch sogenannte Spiralrillenlager gebildet, die einen engen Spalt und auf einer ihrer Lagerflächen ein Muster von Rillen aufweisen. In dem Lagerspalt, der auf der einen Seite durch eine glatte Lagerfläche und auf der anderen Seite durch die Fläche mit dem Rillenmuster begrenzt wird, befindet sich das Schmiermittel. Die Rillen sind so geformt, daß beim Betrieb der Drehanoden-Röntgenröhre mit einer vorgegebenen Drehrichtung das Schmiermittel im Lager bleibt. An das Spiralrillenlager grenzt eine Oberfläche an, die so präpariert ist, daß sie von dem Schmiermittel nicht benetzt werden kann, z.B. durch eine Titanoxid- oder Siliziumoxid-Carbidschicht.The invention relates to a rotating anode X-ray tube with at least one slide bearing which is filled with a liquid lubricant. Such an X-ray tube is among others known from EP-A-0 141 476. The slide bearings for mounting the rotating anode are formed by so-called spiral groove bearings, which have a narrow gap and a pattern of grooves on one of their bearing surfaces. The lubricant is located in the bearing gap, which is delimited on one side by a smooth bearing surface and on the other side by the surface with the groove pattern. The grooves are shaped so that the lubricant remains in the bearing during operation of the rotating anode X-ray tube with a predetermined direction of rotation. The spiral groove bearing is adjoined by a surface which is prepared in such a way that it cannot be wetted by the lubricant, e.g. through a titanium oxide or silicon oxide carbide layer.
Bei derartigen Drehanoden-Röntgenröhren kann es insbesondere beim Transport passieren, daß Schmiermitteltropfen aus dem Lager austreten und in den Teil des Vakuumraums der Röntgenröhre gelangen, der im Betrieb der Röhre einem starken elektrischen Feld ausgesetzt ist. Diese Schmiermitteltropfen beeinträchtigen die Hochspannungsfestigkeit der Röntgenröhre und können zu deren Zerstörung führen.With such rotating anode X-ray tubes, it can happen, in particular during transport, that lubricant drops emerge from the bearing and reach the part of the vacuum space of the X-ray tube which is exposed to a strong electric field during operation of the tube. These drops of lubricant impair the high-voltage strength of the X-ray tube and can lead to its destruction.
Es ist Aufgabe der vorliegenden Erfindung, eine Drehanoden-Röntgenröhre der eingangs genannten Art so auszugestalten, daß der Betrieb der Röntgenröhre durch aus dem Gleitlager ausgetretene Schmiermitteltropfen nicht beeinträchtigt werden kann.It is an object of the present invention to design a rotating anode X-ray tube of the type mentioned at the outset in such a way that the operation of the X-ray tube is not impaired by lubricant drops escaping from the slide bearing can be.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Oberflächen in dem Öffnungsbereich, über den das Spiralrillenlager mit dem übrigen Vakuumraum der Röntgenröhre in Verbindung steht, aus einem Material bestehen, das vom Schmiermittel benetzbar ist und damit Mischphasen oder Legierungen bilden kann.This object is achieved in that the surfaces in the opening area, via which the spiral groove bearing is connected to the rest of the vacuum space of the X-ray tube, consist of a material which can be wetted by the lubricant and can thus form mixed phases or alloys.
Bei der Erfindung besteht die Oberfläche des Öffnungsbereiches, durch den das Schmiermittel hindurchtreten muß, um aus dem Lager in den übrigen ,im Betriebszustand mit einem elektrischen Feld erfüllten Vakuumraum zu gelangen, aus einem Material, das vom Schmiermittel benetzbar ist und damit Mischphasen bildet. Das Schmiermittel kann dabei also nicht in den im Betriebszustand mit einem elektrischen Feld erfüllten Raum austreten, weil es auf der Oberfläche im Öffnungsbereich haften bleibt und in diese hineindiffundiert. Der Bereich bis zum unter Hochspannung stehenden Vakuumraum sollte nach Möglichkeit als Labyrinth ausgebildet sein.In the invention, the surface of the opening area, through which the lubricant has to pass in order to get out of the bearing into the remaining vacuum space which is filled with an electric field in the operating state, consists of a material which can be wetted by the lubricant and thus forms mixed phases. The lubricant can therefore not escape into the space filled with an electric field in the operating state, because it adheres to the surface in the opening area and diffuses into it. The area up to the high-voltage vacuum space should be designed as a labyrinth if possible.
Das Schmiermittel und das Oberflächenmaterial im Öffnungsbereich müssen aufeinander abgestimmt sein. Als Schmiermittel von Gleitlagern bei Röntgenröhren eignen sich bekanntlich Galliumlegierungen. Diese Legierungen bilden mit vielen Metallen eine Mischphase, d.h. eine neue Legierung, oft jedoch erst dann, wenn die durch Oxide oder Carbide passivierten Oberflächen der Metalle zerstört sind. Es eignen sich daher nur die Metalle, die solche Grenzschichten nicht bilden (Edelmetalle) oder bei denen diese Grenzschichten durch die mit der Konditionierung von Röntgenröhren verbundenen Pump- und Ausheizprozesse zerstört werden, beispielsweise Kupfer. Eine bevorzugte Weiterbildung sieht daher vor, daß das Schmiermittel aus einer Galliumlegierung und die Oberfläche im Öffnungsbereich aus einem Edelmetall besteht. Ein Schmiermitteltropfen aus einer Galliumlegierung breitet sich auf einer z.B. vergoldeten Metallfläche infolge der Benetzung und Legierungsbildung aus und diffundiert in das Grundmaterial hinein, besonders bei erhöhten Temperaturen, jedoch auch schon bei Raumtemperatur.The lubricant and the surface material in the opening area must be coordinated. As is known, gallium alloys are suitable as lubricants for slide bearings in X-ray tubes. These alloys form a mixed phase with many metals, ie a new alloy, but often only when the surfaces of the metals passivated by oxides or carbides have been destroyed. Only metals that do not form such boundary layers (noble metals) or in which these boundary layers are destroyed by the pumping and heating processes associated with the conditioning of X-ray tubes, for example copper, are therefore suitable. A preferred further development provides that the lubricant is made of a gallium alloy and the surface in the opening area consists of a precious metal. A drop of lubricant made of a gallium alloy spreads on an eg gold-plated metal surface due to the wetting and alloying and diffuses into the base material, especially at elevated temperatures, but also at room temperature.
Wenn die erfindungsgemäß vorgesehenen, vom Schmiermittel benetzbaren und damit Mischphasen bildenden Oberflächen unmittelbar an die Gleitlagerflächen angrenzen würden, würde das Schmiermittel relativ leicht aus dem Gleitlager auf diese Flächen übergehen, was einen unerwünschten Schmiermittelverlust zur Folge hätte. Dieser läßt sich in weiterer Ausgestaltung der Erfindung dadurch verringern, daß die unmittelbar an das Spiralrillenlager angrenzenden Oberflächen aus einem Material bestehen, das vom Schmiermittel nicht benetzbar ist und daß sich daran die vom Schmiermittel benetzbaren und damit Mischphasen bildenden Oberflächen anschließen. Bei einer Galliumlegierung als Schmiermittel können nicht benetzbare Oberflächen durch z.B. Titanoxid-Carbid-Beschichtungen oder Siliziumoxid-Carbid-Beschichtungen erzeugt werden.If the surfaces provided according to the invention, which are wettable by the lubricant and thus form mixed phases, directly adjoin the slide bearing surfaces, the lubricant would pass relatively easily from the slide bearing to these surfaces, which would result in an undesirable loss of lubricant. This can be reduced in a further embodiment of the invention in that the surfaces immediately adjacent to the spiral groove bearing consist of a material that is not wettable by the lubricant and that the surfaces wettable by the lubricant and thus forming mixed phases are connected. With a gallium alloy as a lubricant, non-wettable surfaces can be e.g. Titanium oxide carbide coatings or silicon oxide carbide coatings are generated.
Die Erfindung wird nachstehend anhand der Zeichnung näher erläutert, die eine erfindungsgemäße Drehanoden-Röntgenröhre in einem die Drehachse enthaltenden Querschnitt zeigt.The invention is explained in more detail below with reference to the drawing, which shows a rotating anode X-ray tube according to the invention in a cross section containing the axis of rotation.
Die in der Zeichnung dargestellte Röntgenröhre besitzt einen Metallkolben 1, in dem ein Strahlenaustrittsfenster 2, z.B. aus Beryllium, vorgesehen ist, und der an einem ersten Isolator 3 die Kathode 4 und an einem zweiten Isolator 5 die Drehanode 6 trägt. Die Drehanode 6 umfaßt eine Anodenscheibe 7, von der im Betrieb die Röntgenstrahlung ausgeht, und die über ein Lager mit dem zweiten Isolator 5 verbunden ist. Der feststehende Teil des Lagers umfaßt eine Achse 8 aus einer Molybdänlegierung, die über einen Trägerkörper 9 aus einer Eisen-Nickel-Kobald-Legierung (Vacon) mit dem Isolator 5 verbunden ist. Über den Teil 9 wird die positive Hochspannung für die Drehanode zugeführt. Der rotierende Teil 10 des Lagers 6 umfaßt eine zur Achse 8 konzentrische Lagerbuchse 10, die ebenfalls aus einer Molybdänlegierung besteht und den Abmessungen der Achse 8 angepaßt ist, so daß zwischen der Achse 8 und der Buchse 10 nur ein enger Spalt verbleibt, der wesentlich enger ist als in der Zeichnung dargestellt und der z.B. 20 »m dick ist.The X-ray tube shown in the drawing has a
Das Lager ist ein Gleitlager in Form eines Spiralrillenlagers. Zu diesem Zweck ist die Achse 8 mit zwei in axialer Richtung gegeneinander versetzten, fischgrätartigen Rillenmustern 12 versehen, die als Radiallager wirken. Die Achse 8 enthält darüberhinaus eine zylinderförmige Verdickung 13, deren Stirnflächen ebenfalls mit einem nicht näher dargestellten Rillenmuster versehen sind, und daher als Spiralrillenlager für die axiale Lagerung der Anode 6 wirken. Wegen der Verdickung 13 kann die Buchse 10 nicht einteilig sein - wie in der Zeichnung dargestellt - sondern muß aus mindestens zwei Teilen bestehen, die so miteinanderverbunden sind, daß das Schmiermittel durch die Verbindungsbereiche nicht austreten kann. In dem Zwischenraum zwischen der Achse 8 und der Buchse 10 befindet sich als Schmiermittel 14 eine Galliumlegierung (GaInSn). Dieses Schmiermittel ist bei Raumtemperatur flüssig und benetzt die Oberflächen der Achse 8 und der Buchse 10, ohne damit Legierungen einzugehen.The bearing is a plain bearing in the form of a spiral groove bearing. For this purpose, the axis 8 is provided with two
Es läßt sich in der Praxis nicht vermeiden, daß aus dem Lager insbesondere durch stoßartige mechanische Beanspruchungen Schmiermittel austritt. Wenn dieses in den Teil des Vakuumraums der Röntgenröhre gelangt, in dem im Betriebszustand ein starkes elektrisches Feld herrscht, kann die Röntgenröhre zerstört werden. Da das Lager zur Anodenscheibe hin hermetisch abgeschlossen ist, kann das Schmiermittel nur zwischen dem unteren Teil der Achse 8 und der Buchse 10 sowie zwischen der Außenfläche des Trägerkörpers 9 und der Oberfläche des Rotors 11 hindurch in diesen Raum gelangen, wobei es mit hoher Wahrscheinlichkeit auf den Isolator 5 trifft und dort Hochspannungsdurchschläge hervorruft.In practice, it cannot be avoided that from the bearing, in particular due to sudden mechanical stresses Lubricant leaks. If this gets into the part of the vacuum space of the X-ray tube in which there is a strong electric field in the operating state, the X-ray tube can be destroyed. Since the bearing is hermetically sealed towards the anode disk, the lubricant can only get into this space between the lower part of the axis 8 and the
Dies wird dadurch verhindert, daß die Oberflächen in dem Öffnungsbereich, durch den hindurch das aus dem Lager austretende Schmiermittel in den übrigen Vakuumraum der Röntgenröhre gelangt, vergoldet sind. Dies ist durch dick ausgezogene Linien 15 auf der Außenfläche des Trägerkörpers 9 und der ihr zugewandten Fläche der Buchse 10 und der Innenfläche des Rotors 11 angedeutet. Die das Schmiermittel bildende Galliumlegierung benetzt vergoldete Metallflächen und bildet damit bereits bei Raumtemperatur eine neue Legierung. Ein Schmiermitteltropfen bleibt also auf diesen Metallflächen im feldfreien Bereich haften und kann nicht in den vom Feld erfüllten Vakuumraum der Röntgenröhre austreten. Vorteilhafterweise sind die Oberflächen im Öffnungsbereich labyrinthartig angeordnet.This is prevented by the fact that the surfaces in the opening area through which the lubricant emerging from the bearing passes into the remaining vacuum space of the X-ray tube are gold-plated. This is indicated by thick
Wie sich aus dem Vorstehenden ergibt, muß die Oberfläche im Öffnungsbereich so beschaffen sein, daß sie leicht von dem Schmiermittel benetzt werden kann und mit diesem eine Legierung bildet. Für Gallium als Schmiermittel zählen dazu die Edelmetalle - u.a. Gold - aber auch andere Metalle. Allerdings ist die Oberfläche der nicht zu den Edelmetallen gehörenden Metalle meist durch Oxide oder Carbide passiviert, so daß ein Galliumtropfen darauf nicht haften bleibt. Bei einigen dieser Metalle (beispielsweise bei Kupfer) werden diese Schichten durch die Pump- und Ausheizprozesse weitgehend zerstört, denen eine Röntgenröhre vor der ersten Inbetriebnahme unterzogen werden muß. Auf einer ca. 100°C heißen Kupferoberfläche kommt es auch zur Benetzung und damit zum Einfangen eines Schmiermitteltropfens. Die Vergoldung der Innenfläche des Kupferrotors 11 könnte also unter der Voraussetzung entfallen, daß die Kupferoberfläche nicht kontaminiert ist und auf mindestens 100°C gehalten wird.As can be seen from the above, the surface in the opening area must be such that it can be easily wetted by the lubricant and forms an alloy with it. For gallium as a lubricant, this includes precious metals - including gold - but also other metals. However, the surface of the non-precious metals is mostly passivated by oxides or carbides, so that a drop of gallium is not on it sticks. With some of these metals (e.g. copper), these layers are largely destroyed by the pumping and baking processes, which an X-ray tube must be subjected to before the first start-up. Wetting occurs on an approx. 100 ° C hot copper surface and thus traps a lubricant drop. The gold plating of the inner surface of the
Aus dem Lager ausgetretenes Gallium, das auf der vergoldeten Oberfläche des Trägerkörpers 9 haften bleibt, diffundiert im Laufe der Zeit auch in den Trägerkörper 9 ein, der aus einer Eisen-Nickel-Kobalt-Legierung besteht, deren thermischer Ausdehnungskoeffizient dem des Isolators 5 angepaßt ist. Dieser Trägerkörper nimmt also auch das ausgelaufene Schmiermittel nach und nach auf, was insbesondere den Vorteil hat, daß die teure Goldschicht sehr dünn sein kann. Würde dieser Trägerkörper ohne Vergoldung mit dem Schmiermittel in Berührung kommen, würden die auf der Oberfläche vorhandenen Oxid- oder Carbid-Grenzschichten ein Haftenbleiben des Schmiermittels verhindern. Die Goldschicht muß so auf dem Trägerkörper verankert werden, daß die störenden Grenzschichten zerstört werden, z.B. durch bekannte galvanische Präparationsmethoden.Gallium escaping from the bearing, which adheres to the gold-plated surface of the
Wenn die vom Schmiermittel benetzbaren Oberflächen - und dazu zählen auch die Oberflächen der Lagerbuchse 10 und der Achse 8 im unteren Bereich - unmittelbar bis an die Gleitlager heranreichen würden, dann könnte das Schmiermittel relativ leicht auch diese Oberflächen benetzen und würde dabei dem Lager entzogen. Um dieses zu vermeiden, sind die Oberflächen im unteren Bereich der Achse 8 und des Lagers 10, wie durch die gepunkteten Linien angedeutet, mit einer Schicht versehen, die eine Benetzung durch das Schmiermittel verhindert. Eine geeignete Schicht besteht beispielsweise aus Titanoxid-Carbid. Sie verhindert, daß im normalen Betrieb Schmiermittel aus dem Lager läuft. Erst wenn gleichwohl durch starke mechanische Stöße oder dergleichen das Schmiermittel diesen nicht benetzbaren, als kapillar wirksamen Bereich überwunden hat, trifft es auf die erfindungsgemäße Schicht, an der es haften bleibt.If the surfaces wettable by the lubricant - and this also includes the surfaces of the
Claims (7)
- A rotary-anode X-ray tube with at least one sleeve bearing which is filled with a liquid lubricant, characterized in that the surfaces (15) at the opening area via which the sleeve bearing (8,10,12) communicates with the remaining vacuum space of the X-ray tube consists of a material which can be wetted by the lubricant and can form mixed phases or alloys therewith.
- A rotary-anode X-ray tube as claimed in Claim 1, characterized in that the surfaces (15) at the opening area are formed by layers deposited on a support element (9).
- A rotary-anode X-ray tube as claimed in Claim 1 or 2, characterized in that the lubricant consists of a gallium alloy and the surfaces (15) at the gap area consist of a precious metal.
- A rotary-anode X-ray tube as claimed in Claim 3, characterized in that the surfaces (15) consist of gold.
- A rotary-anode X-ray tube as claimed in any one of Claims 2 to 4, characterized in that the support element (9) consists of a material which likewise forms a mixed phase or alloy with the lubricant.
- A rotary-anode X-ray tube as claimed in any one of Claims 1 to 5, characterized in that the surfaces directly adjacent to the helical groove bearing consist of a material which cannot be wetted by the lubricant and that these surfaces are adjoined by the surfaces which can be wetted by the lubricant and form mixed phases therewith.
- A rotary-anode X-ray tube as claimed in Claim 6, characterized in that the lubricant consists of a gallium alloy and that the surfaces directly adjacent to the helical groove bearing are coated with titanium-oxide carbide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3842034 | 1988-12-14 | ||
| DE3842034A DE3842034A1 (en) | 1988-12-14 | 1988-12-14 | TURNING ANODE TUBE TUBE WITH LIQUID LUBRICANT |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0373705A2 EP0373705A2 (en) | 1990-06-20 |
| EP0373705A3 EP0373705A3 (en) | 1991-01-30 |
| EP0373705B1 true EP0373705B1 (en) | 1994-06-15 |
Family
ID=6369117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89203122A Expired - Lifetime EP0373705B1 (en) | 1988-12-14 | 1989-12-08 | Rotating anode X-ray tube with a liquid lubricant |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5077776A (en) |
| EP (1) | EP0373705B1 (en) |
| JP (1) | JP2960085B2 (en) |
| DE (2) | DE3842034A1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5169243A (en) * | 1990-09-28 | 1992-12-08 | Koyo Seiko Co., Ltd. | Dynamic pressure bearing for an x-ray tube having a rotary anode |
| CA2052473C (en) * | 1990-10-01 | 1997-01-14 | Hidero Anno | Rotary-anode type x-ray tube having a ceramic bearing surface |
| CN1024235C (en) * | 1990-10-05 | 1994-04-13 | 株式会社东芝 | Rotary anode type X-ray tube |
| CN1022007C (en) * | 1990-10-05 | 1993-09-01 | 东芝株式会社 | Rotary anode type x-ray tube |
| US5737387A (en) * | 1994-03-11 | 1998-04-07 | Arch Development Corporation | Cooling for a rotating anode X-ray tube |
| DE19523163A1 (en) * | 1994-07-12 | 1996-01-18 | Siemens Ag | Slide bearing part for liquid metal slide bearing used in rotary anode X-ray tube |
| JP3093581B2 (en) | 1994-10-13 | 2000-10-03 | 株式会社東芝 | Rotating anode X-ray tube and method of manufacturing the same |
| DE19510067A1 (en) * | 1995-03-20 | 1996-10-02 | Siemens Ag | Bearing for with liquid metal positioning device for X-ray tube |
| DE19510068A1 (en) * | 1995-03-20 | 1996-10-02 | Siemens Ag | Liquid metal bearing for medical X-ray tube |
| DE19606871C2 (en) * | 1996-02-23 | 1998-12-10 | Siemens Ag | Plain bearings with a bearing gap filled with liquid metal |
| DE19630351C1 (en) * | 1996-07-26 | 1997-11-27 | Siemens Ag | X=ray tube with liquid metal sliding bearing |
| WO2003019610A1 (en) | 2001-08-29 | 2003-03-06 | Kabushiki Kaisha Toshiba | Rotary positive pole type x-ray tube |
| US6891928B2 (en) * | 2003-05-07 | 2005-05-10 | Ge Medical Systems | Liquid metal gasket in x-ray tubes |
| WO2006046181A1 (en) * | 2004-10-26 | 2006-05-04 | Koninklijke Philips Electronics N.V. | Molybdenum-molybdenum brazing and rotary-anode x-ray tube comprising such a brazing |
| US8503615B2 (en) | 2010-10-29 | 2013-08-06 | General Electric Company | Active thermal control of X-ray tubes |
| US8848875B2 (en) | 2010-10-29 | 2014-09-30 | General Electric Company | Enhanced barrier for liquid metal bearings |
| US8744047B2 (en) | 2010-10-29 | 2014-06-03 | General Electric Company | X-ray tube thermal transfer method and system |
| DE102013215977B4 (en) | 2013-08-13 | 2021-02-04 | Siemens Healthcare Gmbh | Liquid metal plain bearings |
| US9500226B2 (en) * | 2014-08-13 | 2016-11-22 | General Electric Company | Method and systems for texturing liquid bearing surfaces in X-ray tubes |
| US9911570B2 (en) | 2015-12-14 | 2018-03-06 | Varex Imaging Corporation | Antiwetting coating for liquid metal |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7713634A (en) * | 1977-12-09 | 1979-06-12 | Philips Nv | ROSE TUBE WITH TWIST CODE. |
| NL8303833A (en) * | 1983-11-08 | 1985-06-03 | Philips Nv | SPIRAL GROOVE BEARING WITH METAL LUBRICATION AND ANTI-WET LAYER. |
| NL8303832A (en) * | 1983-11-08 | 1985-06-03 | Philips Nv | ROENTGEN TUBE WITH SPIRAL GROOVE BEARING. |
| NL8601414A (en) * | 1986-06-02 | 1988-01-04 | Philips Nv | ROENTGEN TUBE WITH A TURNING RED. |
-
1988
- 1988-12-14 DE DE3842034A patent/DE3842034A1/en not_active Withdrawn
-
1989
- 1989-12-08 EP EP89203122A patent/EP0373705B1/en not_active Expired - Lifetime
- 1989-12-08 DE DE58907890T patent/DE58907890D1/en not_active Expired - Fee Related
- 1989-12-11 JP JP1321245A patent/JP2960085B2/en not_active Expired - Fee Related
-
1991
- 1991-03-04 US US07/664,421 patent/US5077776A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02244545A (en) | 1990-09-28 |
| DE58907890D1 (en) | 1994-07-21 |
| EP0373705A3 (en) | 1991-01-30 |
| JP2960085B2 (en) | 1999-10-06 |
| EP0373705A2 (en) | 1990-06-20 |
| DE3842034A1 (en) | 1990-06-21 |
| US5077776A (en) | 1991-12-31 |
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