JPH0582058A - X-ray tube with rotary anode - Google Patents

Abstract

PURPOSE:To provide a rotary anode type X-ray tube, which has a highly reliable rotating mechanism part and is free from leakage of a liquid metal lubricant, by ensuring the coupling of a bottom-equipped cylinder constituting part of a bearing with a ring-shaped blocking body to block the opening of the cylinder. CONSTITUTION:A rotor 12 and a stator 15 are furnished, one of which is embodied in the form of a cylinder having a bottom and the other is fitted in the former, and in the opening of the bottom-equipped cylinder a ring-shaped blocking body 16 to block the opening is fitted with the aid of a plurality of bolts 25 made of metal, wherein a thin disc 27 of metal is interposed between the bolts and the blocking body and the bolts and thin disc are welded together.

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 an improvement of a rotary mechanism section for supporting an anode target.

[0002]

2. Description of the Related Art As is well known, a rotary anode type X-ray tube supports a disk-shaped anode target by a rotating body having a bearing and a fixed body, and energizes an electromagnetic coil arranged outside a vacuum container. While rotating this anode target at a high speed, an electron beam emitted from the cathode is applied to the surface of the anode target to emit X-rays. The bearing portion includes a rolling bearing such as a ball bearing, a spiral groove formed on the bearing surface, and gallium (Ga) or gallium-indium-tin (Ga-).
It is composed of a dynamic pressure type slide bearing using a metal lubricant that becomes liquid during operation, such as an In-Sn) alloy. Examples of the latter slide bearing are disclosed in, for example, Japanese Patent Publication No. 60-21463, Japanese Patent Laid-Open No. 60-97536, Japanese Patent Laid-Open No. 60-113817, and Japanese Patent Laid-Open No. 60-1175.
No. 31, JP-A-61-2914, JP-A-62-287555, or JP-A-2-227947.

[0003]

By the way, the latter rotary anode type X-ray tube using the dynamic pressure type sliding bearing is disclosed in Japanese Patent Laid-Open No. Sho 60-62.
As disclosed in Japanese Patent No. 117531, it is necessary to provide a radial direction spiral groove bearing and a thrust direction spiral groove bearing,
Due to the necessity of assembly, one of the rotating body and the fixed body should be a bottomed cylinder, and the other should be fitted inside and the opening of the bottomed cylinder should be closed with a ring-shaped closure. I won't. When using Ga or Ga alloy as a lubricant, it is necessary to use molybdenum (Mo) or tungsten (W) having excellent corrosion resistance as the bearing base material so that the bearing base material is not attacked by the lubricant. is there.

When the bottomed cylinder and the ring-shaped closed body are made of Mo or W and are integrally connected, brazing or welding of these metals is difficult. On the other hand, if the two are connected with a bolt, the bolt may loosen during long-term use, liquid metal lubricant may leak from the internal bearing portion through the gap, or the rotational balance of the rotating body may be impaired. is there.

The present invention solves the above-mentioned inconveniences and ensures the connection between the bottomed cylinder forming a part of the bearing and the ring-shaped closing member closing the opening to prevent the leakage of the liquid metal lubricant. It is an object of the present invention to provide a rotary anode type X-ray tube having a rotation mechanism section which is highly reliable and has high reliability.

[0006]

According to the present invention, one of a rotating body and a fixed body forming a slide bearing forms a bottomed cylinder and the other fits inside thereof, and the opening is formed in the opening of the bottomed cylinder. The ring-shaped opening closing body that closes the opening is connected by a plurality of metal bolts, a thin metal disk is interposed between these bolts and the opening closing body, and each bolt and the thin disk are welded together. It is a rotating anode type X-ray tube.

[0007]

According to the present invention, since a plurality of bolts that connect the bottomed cylinder and the ring-shaped closing member that closes the opening are welded to the thin disk, respectively, even during long-term operation of the X-ray tube. The bolt does not loosen, and therefore, there is no risk of deterioration of the joint condition between the bottomed cylinder and the ring-shaped closing body and leakage of the liquid metal lubricant, and an easily assembled and highly reliable rotation mechanism portion can be obtained.

[0008]

Embodiments will be described below with reference to the drawings.
The same parts are denoted by the same reference numerals. The embodiment shown in FIGS. 1 to 7 has the following configuration. That is, the disk-shaped anode target 11 made of a heavy metal is integrally fixed to the rotating shaft portion 13 protruding from one end of the rotating body 12 by the nut 14. This rotating body 12 has a bottomed cylinder 12a made of Mo, which is integral with the rotating shaft 13 and whose inner peripheral surface serves as a sliding bearing surface, and a ferromagnetic cylinder 12b and a copper cylinder 12c fitted on the outer periphery thereof. ing. A cylindrical fixed body 15 made of Mo is inserted into the inside of the rotor 12 from the rotor opening 12d side. In the lower end portion of the fixed body 15 farther from the anode target, that is, in the vicinity of the opening of the rotating body, a small fixed body diameter portion whose outer diameter is reduced.
15a is provided. And in the rotating body opening 12d,
Surrounding the small part 15a of the fixed body in close proximity to the shoulder end surface of the fixed body
A ring-plate-like Mo-made opening blocker 16 which is close to the rotor 15b and substantially closes the rotary block opening is connected by a plurality of bolts 25, 25 ,. An iron-made anode support 17 for mechanically supporting the rotating body 12 and the fixed body 15 is integrally fixed to the fixed body small-diameter portion 15a by brazing, which is hermetically bonded to a glass vacuum container 18. Has been done.

The fitting portion between the cylindrical rotating body 12 and the fixed body 15 constitutes a dynamic pressure type slide bearing as described in the above-mentioned publications. Therefore, on the outer peripheral surface of the fixed body, which serves as the slide bearing surface, there are formed two spiral grooves 20, 20 of the herringbone pattern as described in the above-mentioned publications. A small lubricant gap between the outer peripheral surface of the fixed body having the spiral groove and the bearing surface composed of the outer peripheral surface of the rotating body in the vicinity of the fixed body is filled and interposed with a metal lubricant which is liquid at least during operation. , A radial dynamic pressure type slide bearing portion 19a is constituted.

A spiral groove 21a having a herringbone pattern as shown in FIG. 3 is formed on the tip surface 15c of the fixed body which is in contact with the inner bottom wall 12e of the bottomed cylinder 12a. A small bearing gap between the fixed body tip bearing surface having the spiral groove 21a and the bearing surface formed of a flat bottom surface of the rotor adjacent to the fixed groove is filled with a metal lubricant which is liquid at least during operation, One thrust direction dynamic pressure type slide bearing portion 19b is interposed and is interposed. On the other hand, on the side farther from the anode target, the bearing surface composed of the shoulder end surface 15b formed by forming the small diameter portion 15a on the fixed body remains flat, and the opening closing body 16 close to this is closed. Bearing surface 16b
The spiral groove 21b having a herringbone pattern as shown in FIG. In the central portion of the opening blocker 16, a small diameter part 15a of the fixed body is provided in the vicinity of the central through hole 16 through which the small part 15a passes.
c is formed, and further a plurality of bolt insertion through holes 16d, 16d, ... Are formed in the outer peripheral portion. In this way, the opening side of the bottomed cylinder of the rotating body has the bearing surface 16b of the opening closing body 16.
And a small bearing gap between the bearing surfaces of the fixed body shoulder end surface adjacent thereto is filled with the metal lubricant which is also liquid at least during operation, and the other thrust direction slide bearing portion 19c is formed. ing. The bearing surfaces of the rotating body and the fixed body are fitted to each other with a bearing gap of about 20 micrometers.

In addition, the fixed body 15 is provided with an axial lubricant containing chamber 22 whose central portion is hollowed out in the axial direction to form a through hole. The illustrated upper end opening of the axial lubricant containing chamber 22 communicates with the bearing gap of the thrust bearing at the tip of the fixed body and through the bearing gap of the radial bearing on the outer peripheral side of the fixed body. Further, the fixed body 15 is formed with a small diameter portion 23 in which the outer peripheral wall of the intermediate portion is slightly tapered, and three radial passages leading from the lubricant containing chamber 22 to the small diameter portion 23 are formed. 24 are formed 120 degrees apart in an axially symmetrical manner. Further, a small diameter circumferential groove 26 is formed inside the thrust direction sliding bearing portion 19c.

In the assembly process, the rotary body 12 having a bottomed cylinder is turned upside down from the state shown in FIG. 1, a predetermined amount of liquid metal lubricant is injected into the internal space, and the fixed body 15 is slowly inserted into it. Then, from the fixed body small diameter portion 15a side, as shown in FIG.
The Mo-made opening blocker 16 shown in FIG. 6 is turned upside down from the state shown in the figure, and is fitted so as to close the opening of the rotating body.
Further, on the opening blocker 16, for example, a thin disk made of iron alloy.
Place 27. Similar bolt insertion holes 27e are formed in the thin circular plate 27 at positions corresponding to the bolt insertion holes 16d of the opening blocker 16. The bolts 25 are inserted into the through holes 27e, 16d for inserting bolts with the thin disk 27 sandwiched therebetween and fastened together as shown in FIG. Each bolt 25
It is made of, for example, an iron alloy that is easily welded to the thin disk 27.

Next, as shown by the arrow B in FIG.
25 and thin circular plate 27 by helicopter arc welding or laser
Partially welded by beam welding. This welded portion is represented by reference numeral 28 in FIG. Since both are made of iron alloy, they can be welded easily and reliably by spot welding. In addition, at the time of this welding, Mo opening closing body
Regardless of whether 16 is melted or not, since each bolt 25 and thin disk 27 are fixed to each other, there is no possibility that each bolt will loosen during the subsequent operation. There is no risk of deterioration of the bonding condition.

The rotating mechanism thus assembled is mounted in a vacuum container, and an X-ray tube is completed through an evacuation process. Then, at a position corresponding to the rotating body 12 outside the vacuum container 18,
An electromagnetic coil of a stator (not shown) is arranged to generate a rotating magnetic field, and the rotating anode is rotated at a high speed as indicated by an arrow P. Then, an electron beam emitted from a cathode (not shown) strikes the anode target 11 to generate X-rays.

In the embodiment shown in FIG. 8, a rotating cylinder 31 which rotates integrally with the anode target 11 is arranged at the center. The fixed body 15 has a flange portion 17a of the anode support portion 17 at the bottom.
The main part is composed of a fixed body bottomed cylinder 32 to which is fixed. A spiral groove 21b is formed on the upper surface of the flange portion 17a. Further, an inner rotary bearing cylinder 35 is brazed and integrated with the lower portion 31a on the outer periphery of the rotary cylinder 31 forming the rotary body 12 through a heat insulating gap 34 held by a plurality of protrusions 33. On the outer peripheral surface and the upper surface of this rotary bearing cylinder,
Helical grooves 20 and 21a are formed. The assembly of the rotary cylinder 31 and the rotary bearing cylinder 35 is inserted inside the fixed body bottomed cylinder 32, and the ring-shaped Mo-made opening closing body 16 is fitted on the upper part, and the thin disk 27 is sandwiched therebetween. Are fastened with a plurality of bolts 25. The bolts 25 and the thin disk 27 are partially welded and fixed. A Ga alloy lubricant is injected between the bearing surfaces including the spiral grooves. Outside the fixed body bottomed cylinder 32, there is a rotor cylinder 12 having a copper cylinder 12c.
b is fitted in a non-contact manner, and its upper part is fixed to the rotary shaft 13.

Also in this embodiment, since a plurality of bolts connecting the bottomed cylinder and the ring-shaped closing body that closes the opening are welded to the thin disk, the X-ray tube operates for a long time. But each bolt does not loosen. The bolts and the thin circular plates may be metals other than iron alloys as long as they are metallic materials having relatively high mechanical strength, reliable mutual welding and easy.

[0017]

As described above, according to the present invention,
The plurality of bolts that connect the bottomed cylinder and the ring-shaped closing body that closes the opening thereof do not loosen during the operation of the X-ray tube, and the state of connection between the bottomed cylinder and the ring-shaped closing body is improved. It is possible to obtain a rotary anode type X-ray tube having a dynamic pressure type sliding bearing performance which is easy to assemble and has high reliability without the risk of deterioration and leakage of the liquid metal lubricant.

[Brief description of drawings]

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

FIG. 2 is a longitudinal sectional view showing an enlarged main part of FIG.

FIG. 3 is a top view taken along line 3-3 of FIG.

FIG. 4 is a top view showing a part of FIG.

FIG. 5 is a partial vertical cross-sectional view showing the respective parts.

FIG. 6 is a vertical sectional view showing the assembled state.

7 is a sectional view taken along line 7-7 in FIG.

FIG. 8 is a vertical sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 11 ... Anode target, 12 ... Rotating body, 12a, 32 ... Bottomed cylinder 15 ... Fixed body, 18 ... Vacuum container, 16 ... Opening block, 20, 21a, 21b ... Helical groove, 25 ... Bolt, 27 ... Thin Discs, 19a, 19b, 19c… Slide bearings.

Claims (1)

[Claims] 1. A rotating body having an anode target partially fixed thereto, a fixed body fitted to the rotating body and rotatably holding the rotating body, and a fitting portion of the rotating body and the fixed body. A rotary anode X-ray tube comprising a slide bearing portion having a spiral groove provided, wherein one of the rotating body or the fixed body forms a bottomed cylinder and the other fits inside thereof. A ring-shaped opening closing body that closes the opening is connected to the opening by a plurality of metal bolts, and a thin metal disk is interposed between these bolts and the opening closing body. A rotating anode type X-ray tube characterized by being welded to a thin disk.