JPH06176720A - Rotation anode type x-ray tube - Google Patents

Abstract

PURPOSE:To obtain a rotation anode type X-ray tube, in which the leak of liquid metal lubricant can be prevented and the stabilized bearing operation can be maintained. CONSTITUTION:A rotation anode type X-ray tube has the volume, of which lower limit is set at a quantity for filling spiral grooves and spaces between bearings thereof with the liquid metal lubricant L filled so as to be supplied to bearing parts 20a, 20b, 22a, 22b of a rotor 12 and a fixed body 15. An upper limit thereof is set at 70% of the space volume inside from the end of a sliding bearing part of a spiral groove nearest to the inner space of a vacuum container, in which the lubricant can be flowed freely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary anode type X-ray tube, and more particularly to a bearing assembly therefor.

[0002]

2. Description of the Related Art As is well known, a rotary anode type X-ray tube supports a disk-shaped anode target with a rotating body having a bearing and a fixed body, and energizes an electromagnetic coil of a stator arranged outside a vacuum container. While rotating at high speed, the electron beam emitted from the cathode is applied to the anode target surface to emit X-rays. The bearing part has a rolling bearing such as a ball bearing, a spiral groove formed on the bearing surface, and gallium (G
a) or gallium-indium-tin (Ga-In-S)
n) A dynamic pressure type slide bearing in which the bearing gap is filled with a liquid metal lubricant such as an alloy. Examples of the latter slide bearings are disclosed in, for example, Japanese Patent Publication No. 60-21463 and JP-A No. 60-97536.
JP-A-60-117531, JP-A-62-287555, and JP-A-2-227948.

[0003]

In the rotary anode type X-ray tubes disclosed in the above publications, the bearing surfaces of the dynamic pressure sliding bearing portion having the spiral groove, which face each other, have a bearing gap of, for example, about 20 micrometers. And the helical groove and the bearing gap are filled with a liquid metal lubricant. If the filling amount of the lubricant is too small, the dynamic pressure of the slide bearing cannot be sufficiently obtained as a matter of course, and the stable operation of the slide bearing cannot be maintained. On the other hand, if there is too much lubricant,
It is easy to leak from the bearing to the outside. In particular, when gas is released from the bearing constituent members or the lubricant during assembly or actual operation of the X-ray tube, a part of the lubricant may be blown out of the bearing together with gas bubbles. If such a phenomenon occurs, a stable dynamic pressure bearing action of the slide bearing for a long time cannot be obtained, and further, the liquid metal lubricant scattered in the space inside the X-ray tube container may seriously impair the withstand voltage performance. Cause disability.

An object of the present invention is to provide a rotating anode type X-ray tube which solves the above-mentioned inconveniences, can prevent leakage of liquid metal lubricant, and can maintain stable bearing operation. .

[0005]

SUMMARY OF THE INVENTION According to the present invention, the amount of the liquid metal lubricant filled so as to be supplied to the bearing portions of the rotating body and the fixed body is set so as to fill the spiral groove and the bearing clearance of the spiral groove portion. The lower limit of the volume of the internal space in which the liquid metal lubricant on the other bearing part side can flow from the end of the spiral groove slide bearing part that is closest to the space inside the vacuum container in terms of space path.
It is a rotary anode type X-ray tube having a volume within a range of 0% as an upper limit.

[0006]

According to the present invention, even if gas is released from the bearing constituent member or the liquid metal lubricant, the gas is generated in the internal space having a volume of 30% or more of the volume of the bearing-side internal space communicating with the bearing portion. Since the volume expands and the pressure drops, the inconvenient phenomenon that the lubricant leaks into the space inside the vacuum container with the gas bubbles hardly occurs. Therefore, stable bearing operation is maintained for a long time.

[0007]

Embodiments will be described below with reference to the drawings.
The same parts are represented by the same symbols. The embodiment shown in FIGS. 1 to 8 has the following configuration. That is, as shown in FIG. 1, the assembled X-ray tube has a disk-shaped anode target 11 made of heavy metal integrated with a nut 14 on a rotary shaft 13 projecting from one end of a bottomed cylindrical rotor 12. Fixed. The rotor 12 has a double rotor cylinder, which is composed of a ferromagnetic cylinder 12a and a good conductor cylinder 12b, coaxially fitted and fixed to the outer periphery of the rotor 12. A cylindrical fixed body 15 is inserted inside the rotating body 12. A fixed body small diameter portion 15a having a reduced outer diameter is formed near the lower end of the fixed body 15 in the figure, that is, near the rotary body opening 12c. The rotating body opening 12c surrounds the fixed body small-diameter portion 15a in close proximity to the ring-shaped opening closing body 16 which substantially closes the opening.
Are fixed by a plurality of bolts 16a. An iron-made anode support 17 for mechanically supporting the rotating body 12 and the fixed body 15 is fixed to the fixed body small-diameter portion 15a by brazing, and this is hermetically joined to a glass vacuum container 18. .

At the fitting portion between the cylindrical rotating body 12 and the fixed body 15, there is formed a dynamic pressure type spiral groove slide bearing portion as shown in the above-mentioned respective publications. That is, on the outer peripheral wall of the fixed body 15, spiral grooves 19a and 19b having a herringbone pattern are formed at predetermined intervals in the axial direction, and two radial sliding bearing portions 20a and 20b are formed. A circular herringbone pattern spiral groove 21a shown in FIG. 2 is formed on the upper end wall of the fixed body 15 shown in FIG. 2 to form one thrust slide bearing portion 22a. Opening block 16
Similarly, a circular herringbone pattern spiral groove 21b shown in FIG. 3 is formed on the upper surface 16c of the above, and the other thrust slide bearing portion 22b is formed. Both bearing surfaces of the rotating body and the fixed body face each other with a bearing gap G of about 20 μm.

The fixed body 15 is provided with a lubricant accommodating chamber 23 which is a hole whose central portion is cut out along the axial direction to a region corresponding to the distance between the pair of thrust bearing portions 22a and 22b. . The illustrated upper end opening 23a of the lubricant containing chamber 23
Is located in the center of the inside of the circular spiral groove 21a in the upper part of the drawing and communicates with the bearing gap G of the thrust bearing portion 22a. Further, the fixed body 15 has a small diameter portion 24 formed by cutting the outer peripheral wall of the intermediate portion thereof, and four radial passages 25 leading from the lubricant containing chamber 23 to the small diameter portion 24 are provided at 90 degree intervals. It is formed symmetrically. Thereby, the lubricant storage chamber
Reference numeral 23 denotes a bearing of two sets of radial bearings 20a, 20b, which communicate with a circumferential space S1 formed by the small diameter portion 24 via a radial passage 25 provided at an intermediate portion in the axial direction and further pass therethrough. It communicates with the gap G. The lower end portion 23b of the lubricant containing chamber 23 shown in the drawing is a lower thrust spiral groove slide bearing portion 22.
It is extended to a position near b and terminates. Between the opening blocker 16 and the small fixed body diameter portion 15a, there is provided a circumferential recess 26 formed by cutting a part of the small fixed body diameter portion into a circumferential shape. The cylindrical portion 16b of the closing body forms a minute gap Q for preventing the leakage of the lubricant with the inner small diameter portion 15a of the fixed body, and has a screw pump groove 27 on the inner peripheral surface. The screw pump groove 27 enhances the lubricant leakage prevention action. The circumferential recess 26 has a size sufficiently larger than the size of the gap Q in the radial direction.

Then, the spiral grooves of the bearings 20a, 20b, 22a, 22b, the bearing gaps, and the lubricant accommodating chamber 23 communicating therewith.
The space S1 formed by the radial passage 25 and the small diameter portion 24 is filled with a liquid metal lubricant L such as Ga alloy by a filling method described later.
Is filled in a predetermined amount. The filling amount of the lubricant L is the end portion of the spiral groove slide bearing portion which is closest to the vacuum container internal space in terms of the space path leading to the vacuum container internal space through the minute gap Q,
That is, from the thrust bearing portion 22b in the lower part of the drawing, the internal space on the side of the other bearing portion, that is, the internal space in which the lubricant can flow, including the spiral groove, the bearing gap, the lubricant accommodating chamber, the radial passage, and the space S1 due to the small diameter portion. The amount of volume corresponding to about 50% of the volume of space. That is, in this embodiment in which the radial passage 25 is in the middle of the upper and lower thrust bearing portions 22a and 22b, and the space volumes of the upper and lower portions are substantially the same, the filling amount of the lubricant is as shown in FIG. This is the volume amount corresponding to the range V from the lower thrust bearing portion 22b to the center position of the radial passage 25 when the lubricant is all in the lower part in the drawing with the axis vertical. Therefore, the water line H of the lubricant substantially coincides with the center line of the radial passage 25. This is
When the rotation axis is vertical with the gap Q facing upward and the rotation axis is vertical, the lubricant L is still filled up to about half of the radial passage 25, and the lubricant containing chamber 23 and the upper half of the radial passage 25 are lubricated. It is not blocked by the agent and communicates with the inner space of the vacuum container through the bearing gap G and the gap Q of the radial bearing portion 20b and the thrust bearing portion 22b on one side.

When filling the liquid metal lubricant,
As shown in FIG. 4, each bearing constituting member is arranged inside a vacuum bell jar 33 having a heater 31 and a part of which is connected to an exhaust pump 32. The rotating body 12 is placed on the ultrasonic vibrator 34, which also serves as a holding table, with its opening 12c facing upward. Inside the vacuum bell jar 33, a fixed body holder 35 for suspending and holding the fixed body 15 is provided, which positions and fixes the fixed body 15 above the rotating body. An opening closing body 16 is held by a holding body (not shown) on the upper outer periphery of the fixed body, and a plurality of bolts 16a for fixing the opening closing body 16 are positioned and held at predetermined positions by a fastener 36. There is. Furthermore,
A lubricant injector 37 containing a liquid metal lubricant such as Ga alloy is provided, and the tip 37a of the injection nozzle is inserted inside the rotor opening 12a as shown by a controller (not shown) outside the bell jar. A predetermined amount of lubricant can be injected into the rotating body. Although not shown, a temperature detector for detecting the temperature of the bearing constituent members 12, 15, ... Is provided.

First, as shown in the figure, each part and control device are arranged, and the inside of the bell jar is, for example, 1 by the exhaust pump 32.
A high vacuum of about 0 ^-3 Pa or less is set. Then, at least each bearing member is heated to a temperature of 200 ° C. or higher, for example, about 450 ° C. by the heater 31 and maintained for a certain time. As a result, the built-in gas is released from each component and the liquid metal lubricant and is exhausted by the pump 32. By this vacuum heat treatment, each bearing member is cleaned.

Next, the tip of the lubricant injection nozzle 37a is inserted into the opening of the rotor as shown in the figure, and the liquid metal lubricant measured as described above is injected into the rotor. In the same figure, the symbol L shows the injected liquid metal lubricant. Due to the ultrasonic vibration, the gas discharged from the inside of the liquid metal lubricant L or the inner wall of the rotor in contact with the liquid metal lubricant L is effectively discharged into the bell jar internal space and exhausted.

Next, the controller is driven and controlled from outside the bell jar to move the lubricant injector 37 to the original position, and the fixed body 15 is slowly lowered from above to rotate the rotary body as shown in FIG. Insert inside 12. As a result, the liquid metal lubricant L on the bottom of the rotating body is prevented from being absorbed by the bearing gap between the two, the spiral groove,
Further, it flows through the radial passage into the lubricant accommodating chamber at the center of the fixed body, and climbs up to the range V from the thrust bearing portion 21a at the lower part of the figure to the radial passage 25 located at the axially intermediate position. The bearing surface in this area is wetted with a lubricant.
In this state, the fixed body 15 may be moved up and down by the piston or simultaneously rotated slowly. Thereby,
The lubricant also wets the bearing surface on the upper side of the drawing, and is almost held by the bearing portion. At this time, if the built-in gas is released from each part and bubbles are generated, the bubbles move upward and are discharged to the outside of the bearing member, and are exhausted by the pump. Instead, the lubricant penetrates into each part. Ultrasonic vibrations further enhance the evacuation of this gas and the displacement action of this gas bubble with the lubricant.

As shown in FIG. 6, with the two members fitted together, the opening blocker 16 is fitted to the rotary member opening 12c, and a plurality of bolts 16a are tightened and fixed by the fasteners 36. . In this state, the lubricant L is located up to about half of the radial passage 25, and the lubricant containing chamber 23 and the radial passage 25 are located.
The upper half of 25 is not blocked by lubricant, and one radial bearing part
20b and the thrust bearing portion 22b communicate with the vacuum exhaust space through the bearing gap G and the gap Q. In this state, if heating in a vacuum is continued and ultrasonic vibration is further applied to it, degassing from the bearing member and the lubricant can be further completed. Then, after performing a vacuum heat treatment for a predetermined time, it is gradually cooled to a room temperature of about 25 ° C. in a vacuum. After that, the anode target 11 is fixed to the rotating shaft 13 with the nut 14. Subsequently, the anode support portion 17 is fitted in the metal ring at the end of the glass vacuum container 18 and hermetically welded. In this way, the anode structure is incorporated inside the glass vacuum container 18 which is an X-ray tube,
Move to the exhaust process of the X-ray tube. In this exhaust process, the gap Q
While the anode target is continuously rotated at about 3000 rpm while facing upward, while heating to, for example, 450 ° C. by electron impact or high-frequency induction heating, gas is released from each component and exhausted, and the chip is cut off to complete the X-ray tube.
In the exhaust step, if the anode assembly is horizontally or obliquely laid down as will be described later, and gas is discharged while the rotating body is rotated to exhaust the gas, the bearing constituent member can be more reliably generated without leakage of the lubricant. The gas can be released from the lubricant or the lubricant and exhausted. At that time, since the volume expansion and the pressure drop of the released gas occur in the internal space without the lubricant, the pressure when the gas bubbles come out to the outside is low, and therefore the lubricant is not extruded together. In this way, the internal gas can be discharged to the outside of the bearing portion without the leakage of the lubricant.

In the bearing structure thus assembled, the liquid metal lubricant L is filled in the bearing gap including the spiral groove, the lubricant accommodating chamber, and the like, and the bearing surface is in a surface state well wetted with the lubricant. Since the filling amount of the lubricant is about half of the space volume in which the lubricant can flow, as shown in FIG. 7, when the rotating shaft is horizontal, the lubricant L is gravitationally applied to the lower bearing surface in the figure. From the central axis to the lubricant storage chamber
It is in the range V up to about the center of 23. Since some lubricant remains in the upper spiral groove and the bearing gap, the lubricant retention range V is slightly reduced, but this is ignored for explanation. Even if gas comes out of the bearing, the gas bubbles have a volume of about 50% without lubricant, such as the upper space of the lubricant containing chamber 23, the upper part of the passage 25, and about half of the space formed by the small diameter portion 24. The volume expands in space and the pressure drops. Then, the lubricant passes through the upper bearing gap and the spiral groove as shown by the arrow so that a passage is easily formed, and the lubricant exits from the gap Q of the closing body 16. Therefore, the lubricant is rarely pushed out of the bearing, and only gas bubbles are discharged. In addition, the thrust bearing portion close to the gap Q
The lubricant in the lower part of 22b is held in the bearing gap due to its surface tension and does not leak to the gap Q.

Similarly, as shown in FIG. 8, even when the closing body 16 is inclined obliquely upward, the lubricant stays in the range V that fills the lubricant containing chamber 23 and almost half of the radial passage.
Therefore, the released gas is complementarily expanded and pressure-decreased in the lubricant-free internal space, and the discharged gas is surely and easily discharged without leakage of the lubricant. In this way, even if gas is released in the bearing portion or the internal space, the lubricant is prevented from leaking out of the bearing, and the rotating anode assembly having a stable dynamic pressure type sliding bearing operation can be obtained.

In the operation of this rotary anode type X-ray tube,
An unillustrated stator, that is, an electromagnetic coil is arranged at a position corresponding to the rotating body 12 outside the vacuum container 18 to generate a rotating magnetic field, and the rotating anode is rotated at a high speed as indicated by an arrow P. The liquefied metal lubricant sufficiently fills the spiral groove slide bearing portion and enables smooth dynamic pressure bearing operation. The liquid metal lubricant moves and circulates in the bearing gap having the central lubricant containing chamber, the radial passage and the spiral groove due to the partial pressure difference due to the operation, reaches the bearing portion, and a stable dynamic pressure is achieved. Used for bearing action. An electron beam emitted from a cathode (not shown) impinges on the anode target to generate X-rays. Most of the heat generated in the target is dissipated by radiation, and part of the heat is dissipated to the outside from the rotating body 12 through the liquid metal lubricant of the bearing portion and the fixed body 15.

In the embodiment shown in FIG. 9, when the minute gap Q for preventing lubricant leakage is directed upward and the rotation axis is vertical,
A radial passage 25 located between the two radial plain bearing portions 20a, 20b is formed at a position approximately 1/3 from below the axial length of the lubricant accommodating chamber 23 on the central axis so that the lubricant L It is filled with an amount corresponding to the range V from the thrust bearing portion 22a to the passage 25. This lubricant filling amount is a volume amount corresponding to about 30% of the internal space volume in which the lubricant on the other bearing portion side can flow from the thrust bearing portion 22b closest to the inner space of the vacuum container in terms of passage. By this, about 2 / of the internal space
A space having a volume corresponding to 3 is secured as a space without lubricant. Therefore, this lubricant-free space also functions as a space that causes volume expansion and pressure drop of the gas discharged from the bearing and a gas discharge passage, and a rotary anode X-ray tube that hardly causes lubricant leakage can be obtained. To be

In the embodiment shown in FIG. 10, when the gap Q is upward and the rotation axis is vertical, the lubricant containing chamber 23 on the central axis is formed only on one side from the radial passage 25 in the axial middle. , Range Va where the lubricant L does not reach the radial passage 25
It was filled so that This lubricant filling amount is a volume corresponding to about 50% of the volume of the lubricant flowable space inside the thrust bearing portion 22b closest to the space inside the vacuum container. In this state, the radial passage 25 is not blocked with the lubricant.

Further, in the same structure as in FIG. 10, the lubricant L may be filled in an amount corresponding to the range Vb from the thrust bearing portion 22a to the passage 25. In this case, the lubricant filling amount is
The volume corresponds to approximately 70% of the volume of the lubricant flowable space inside the thrust bearing portion 22b closest to the space inside the vacuum container. This results in a rotating anode X-ray tube with virtually no leakage of lubricant.

In the embodiment shown in FIG. 11, the lubricant containing chamber and the radial passage are not formed in the fixed body. Also in this case, the lubricant filling amount is a volume corresponding to about 40% of the total internal space volume of the spiral groove in which the lubricant can flow, the bearing gap, and the circumferential space S1 of the small intermediate diameter portion.

In the above-mentioned embodiment, the anode target is fixed to the cylindrical rotating body, but the present invention is not limited to this.
As shown in, the present invention can be applied to a structure in which a cylindrical rotating body 12 in which an anode target is integrally coupled and rotates is arranged on the rotation center axis. That is, the rotary shaft 13 made of a pipe is fixed to the upper part of the cylindrical rotary body 12 in the figure, and the anode target 11 is fixed thereto. Further, a cylindrical fixed body 15 having a bottom is provided so as to surround the rotating body 12. An opening blocker 16 is fastened to the upper end opening 15b of the fixed body 15 in the figure by a plurality of bolts 16a. On the outer periphery of the fixed body 15, a ferromagnetic body cylinder 41 functioning as a rotor cylinder of the motor and a copper outermost cylinder 42 fitted on the outer side thereof are fitted.
Are arranged coaxially. The upper end 41a of the ferromagnetic cylinder 41 is mechanically firmly fixed to the rotary shaft 13.
The opening blocker 16 is in contact with the upper end surface of the rotating body 12, and the spiral groove 21 is formed on the contact surface. The lower half of the inner peripheral wall near the rotation axis of the opening blocker 16 and the rotary body 12
A cavity 26 that is hollowed out in a circumferential shape is formed around the rotation axis of the. The cavity 26 is provided so as to communicate with the inner end of the bearing gap G of the thrust bearing portion 22b. Further, in the middle of communicating with the space inside the vacuum container through the gap between the cavity 26 and the outer peripheral wall of the fixed body and the inner peripheral wall of the ferromagnetic cylinder, a minute gap Q for preventing lubricant leakage and a folded portion 43 in the radial direction. Is provided. In addition, a coating film to which the liquid metal lubricant adheres and reacts may be formed on the inner surface of the folded portion 43. As a result, even if a part of the lubricant leaks out to around this, it will adhere to the inner surface of the folded-back portion 43 and will not leak out to the outside. The liquid metal lubricant L has a volume corresponding to about 50% of the space volume in which the lubricant can flow from the thrust bearing portion 22b closest to the space inside the vacuum container. Thereby, the lubricant containing chamber 23 and the radial passage 25 are
A rotary anode type X-ray tube having a bearing structure that is not blocked by a lubricant, functions as a gas volume expansion and decompression of the gas discharged from the bearing portion, and as a gas discharge passage, and does not leak a lubricant can be obtained.

In the embodiment shown in FIG. 13, a large diameter portion 15c is formed at a position close to the anode target 11 of the fixed body 15, and a spiral groove 21 having a circular herringbone pattern is formed on both end faces thereof.
Two thrust bearing portions 22a and 22b having a and 21b are formed. The two radial bearing parts 20a, 20b are
The spiral groove 19a, 19b formed in the fixed body 15 extending downward in the drawing from the large-diameter portion 15c constitutes a portion closer to the minute gap Q. The opening 23 of the lubricant containing chamber 23 formed in the fixed body 15
a is opened in a gap S2 formed between the end surface of the fixed body and the bottom surface of the rotating body. One radial passage 25 opens into a gap S3 on the outer circumference of the large diameter portion 15c, and communicates with the bearing gap G and the spiral groove of the thrust bearing via the gap S3 between this surface and the inner circumferential surface of the rotor. is doing. The gaps S2 and S3 in which the lubricant accommodating chamber 23 and the passage 25 are opened are in the region where the dynamic pressure by the lubricant is relatively low during the rotating operation. The other radial passage 25 opens toward the gap S1 formed by the small diameter portion 24 between the two sets of radial bearings. The lubricant L flows from the outer end of the spiral groove slide bearing portion 20b closest to the space inside the vacuum container to the spiral groove inside the bearing structure, the bearing gap, each space, the lubricant accommodating chamber and each passage. A volume corresponding to about 20% of the possible space volume is filled. Therefore, with the gap Q facing upward, neither of the two radial passages 25, 25 is blocked by the lubricant. As a result, it is possible to surely and easily discharge the gas, and to obtain a rotating anode type X-ray tube having a bearing structure in which lubricant does not leak.

In the embodiment shown in FIG. 14, two thrust bearing portions 22a and 22b are provided near the gap Q, and two radial bearing portions 20a and 20b are provided near the target 11. The radial passages 25, 25 are formed between the bearings. The lubricant L is filled from the position of the slide bearing portion 22b closest to the space inside the vacuum container to a volume V equivalent amount corresponding to about 50% of the lubricant flowable space volume inside the bearing assembly. As a result, the radial passage 25 between the two thrust bearing portions 22a and 22b is not blocked by the lubricant when the gap Q is placed upward. by this,
It is possible to surely and easily discharge the gas, and to obtain a rotating anode type X-ray tube having a bearing structure without leakage of the lubricant.

At least one of the radial passages is lubricated with three or more axial passages extending from the lubricant accommodating chamber in the axial direction, with the gap Q facing upward and the rotation axis vertical. It may be prevented from being blocked by the agent.

In the embodiment shown in FIG. 15, a cavity 51 is formed by hollowing out a central portion near the tip of the fixed body 15 relatively large. Then, the pipe 52 is arranged and partitioned so as to pass through the center of the cavity 51, and both ends of the pipe are joined to the fixed body 15 by brazing. The pipe 52 is connected to the lubricant containing chamber 23 at the center of the fixed body, and also functions as a lubricant containing chamber. In addition, a plurality of minute through holes 53 are provided at two locations of this pipe 52. These small through holes 53
May be formed in such a size that the liquid metal lubricant cannot pass therethrough, and in that case, the cavity 51 becomes a vacuum space and functions as a space for temporary volume expansion and decompression when gas is generated inside. Alternatively, the through hole 53 may be formed to have a relatively large size through which the liquid metal lubricant passes. In that case
51 also functions as a lubricant containing chamber in which the lubricant can flow and a space for temporary volume expansion and decompression when gas is generated inside. In any case, the filling amount of the lubricant is equivalent to 70% of the internal space volume in which the lubricant can flow, more preferably 5
The upper limit is equivalent to 0%.

As described above, the lower limit of the filling amount of the lubricant is to fill the spiral groove and the bearing gap G in the region where the spiral groove is present. And the upper limit of the filling amount is the space volume that allows the lubricant inside to flow from the end of the spiral groove slide bearing closest to the space inside the vacuum container, that is, the spiral groove inside the bearing structure, the bearing gap, each space, the lubricant storage The volume is equivalent to 70% of the space volume including the chamber and each passage. If the filling amount of the lubricant exceeds 70% of the internal space volume, the volume expansion and depressurization of the released gas become insufficient, and the possibility of extruding the lubricant increases, causing the liquid metal to scatter in the space inside the vacuum container. Therefore, the catastrophic damage that induces the discharge of the X-ray tube is likely to occur.

As described above, the filling amount of the lubricant is more preferably the upper limit of 50% of the internal space volume in which the lubricant can flow. Most preferably, the fill amount is a volume in the range of 20% to 50% of the internal space volume in which the lubricant can flow.

A reaction layer of the bearing base material and the lubricant may be thinly formed in advance on the slide bearing surface having at least the spiral groove of each bearing component member. Alternatively, the reaction layer of the bearing base material and the lubricant may be thinly formed on each bearing surface by the vacuum heat treatment in the lubricant filling step shown in FIGS. 4 to 6 described above. In this case, the filling amount of the lubricant is larger than that consumed by the formation of the reaction layer, and it is desirable to inject the lubricant.

The metal lubricant is Ga or Ga-I.
An alloy mainly composed of Ga such as an n alloy or a Ga—In—Sn alloy can be used, but is not limited thereto. For example, Bi—In—Pb containing a relatively large amount of bismuth (Bi).
-Sn alloy or In-B containing a relatively large amount of In
An i alloy or an In-Bi-Sn alloy may be used. Since these have a melting point of room temperature or higher, it is desirable to preheat the metal lubricant to a temperature equal to or higher than the melting point before rotating the anode target and then rotate the target.

[0032]

As described above, according to the present invention,
Even if gas is released from the bearing components or liquid metal lubricant, it causes volume expansion of gas bubbles in the internal space and reduces the pressure to prevent lubricant from leaking and maintain stable bearing operation. An anode type X-ray tube is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a top view showing a main part of FIG.

FIG. 3 is a top view showing a main part of FIG.

FIG. 4 is a longitudinal sectional view of an essential part showing a state in an assembly process.

FIG. 5 is an enlarged vertical sectional view of an essential part showing a state in an assembling process.

FIG. 6 is a vertical sectional view showing a state in an assembling process.

FIG. 7 is a vertical cross-sectional view showing the main parts of the one in FIG.

FIG. 8 is a vertical cross-sectional view showing a main part of the one in FIG. 1 in an assembled or used state.

FIG. 9 is a longitudinal sectional view of a main part showing another embodiment of the present invention.

FIG. 10 is a vertical sectional view showing still another embodiment of the present invention.

FIG. 11 is a vertical sectional view showing still another embodiment of the present invention.

FIG. 12 is a vertical sectional view showing still another embodiment of the present invention.

FIG. 13 is a vertical sectional view showing still another embodiment of the present invention.

FIG. 14 is a vertical sectional view showing still another embodiment of the present invention.

FIG. 15 is a vertical sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 11 ... Anode target, 12 ... Rotating body, 15 ... Fixed body, 18 ... Vacuum container, 20a, 20b ... Radial plain bearing part, 22a, 22b ... Thrust plain bearing part, 23 ... Lubricant accommodating chamber, 25 ... Radial passage , 50 ... cavity, G ... bearing gap, L ... liquid metal lubricant, Q ... minute gap.

Claims (4)

[Claims] 1. An anode target arranged inside a vacuum container, a rotating body to which the anode target is fixed, a fixed body for rotatably holding the rotating body, and a mutual proximity of the rotating body and the fixed body. A rotary anode type X-ray tube comprising a plurality of spiral groove slide bearing portions provided in a part of the portion and a liquid metal lubricant supplied to the spiral groove and the bearing gap of the slide bearing portion. The lower limit of the amount of metal lubricant filled is the amount that fills the spiral groove and the bearing gap of the spiral groove portion, and the end of the spiral groove sliding bearing portion that is closest to the space inside the vacuum vessel in terms of space path. A rotating anode type X-ray tube having a volume within a range having an upper limit of 70% of the volume of the internal space in which the liquid metal lubricant on the part side can flow. 2. The rotary anode type X-ray tube according to claim 1, wherein the filling amount of the liquid metal lubricant is a volume within a range in which the upper limit is 50% of the internal space volume in which the liquid metal lubricant can flow. 3. The filling amount of the liquid metal lubricant is 20% to 50% of the internal space volume in which the liquid metal lubricant can flow.
The rotary anode type X-ray tube according to claim 1, having a volume in the range of. 4. An anode target arranged inside a vacuum container, a rotating body to which the anode target is fixed, a fixed body for rotatably holding the rotating body, and a mutual proximity of the rotating body and the fixed body. A rotary anode type X-ray tube comprising a plurality of spiral groove slide bearing portions provided in a part of the portion and a liquid metal lubricant supplied to the spiral groove and the bearing gap of the slide bearing portion. A lubricant accommodating chamber extending in the axial direction is provided in the fixed body or the rotating body located above, and a bearing gap extending radially from the lubricant accommodating chamber is provided at at least one position in the axial direction of the lubricant accommodating chamber. A radial passage communicating with the liquid metal lubricant is formed, and the filling amount of the liquid metal lubricant is such that the liquid metal lubricant does not block the at least one radial passage when the rotation axis is vertical. Rotating anode X-ray tube according to.