JPH11273600A - Rotary anode type x-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray tube capable of maintaining stable operation of the bearing part by constituting at least one of the surface part of a rotary body and the surface part of a fixed body forming bearing clearance out of a quenched steel material. SOLUTION: Both bearing surface of a rotary body 12 and a fixed body 23 keep bearing clearance of about 20 μm in operation. The bearing surface of the rotary body 12 in close vicinity to the bearing surface of the fixed body 23 having a spiral groove may be the surface having the smooth surface or a spiral groove. A liquid metal lubricant composed of a Ga-In-Sn alloy is supplied to the bearing clearance. The bearing part of the fixed body 23 having a spiral groove is composed of a quenched steel material. In this case, the whole fixing body 23 may be composed of the quenched steel material, or a cylindrical steel material may be fitted in the surface part of the fixed body 23 by forming a spiral groove on the surface of the quenched cylindrical steel material to thereby facilitate machine work. At least one of the surface part of the rotary body and the fixed body is desirably composed of tool steel or high speed steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotating anode X-ray tube.

[0002]

2. Description of the Related Art In a rotary anode X-ray tube, a rotating body and a fixed body having a bearing portion formed therebetween, a disk-shaped anode target and a cathode connected to the rotating body are respectively arranged in a vacuum vessel. It has a structure. And the electromagnetic coil which becomes a stator is arrange | positioned outside a vacuum container. With such a configuration, the anode target is rotated at high speed by using the induction electromagnetic field generated by the stator, and at the same time, the electron beam is irradiated from the cathode to the anode target surface to generate X-rays.

In a rotating anode type X-ray tube, as a bearing between a rotating body and a fixed body, a gallium (Ga) or gallium-in is formed by forming a rolling bearing such as a ball bearing or a spiral groove on a bearing surface. Di-tin (Ga-I
2. Description of the Related Art A dynamic pressure sliding bearing in which a bearing gap is filled with a liquid metal lubricant such as an n-Sn) alloy is used.

A dynamic pressure sliding bearing and a rotary anode type X-ray tube using the same are disclosed in Japanese Patent Publication No. Sho 60-21463,
244545, JP-A-2-227947,
JP-A-2-227948, JP-B-3-77617
And Japanese Patent Publication No. 7-105885. The manufacturing method is described in
No. 2,997, and Japanese Patent Publication No. 5-290734.

[0005]

In a conventional dynamic pressure sliding bearing used for a rotary anode type X-ray tube, a bearing gap between a rotating body and a fixed body is as small as about 20 μm. A spiral groove is formed. The bearing gap and the spiral groove are filled with a liquid metal lubricant.

[0006] At this time, if the liquid metal lubricant does not spread all over the bearing gap, sufficient dynamic pressure cannot be obtained in the slide bearing, and the dynamic pressure slide bearing cannot maintain stable operation. In an extreme case, the bearing surfaces may be intertwined, making rotation impossible or causing breakage.

An object of the present invention is to solve the above-mentioned drawbacks, and an object of the present invention is to provide a rotating anode type X-ray tube in which a bearing can maintain a stable operation.

[0008]

According to the present invention, there is provided a rotating body to which an anode target is connected, a fixed body fitted to the rotating body via a bearing gap, and a rotating body between the rotating body and the fixed body. Surface of the rotating body forming the bearing gap in a rotary anode type X-ray tube including a dynamic pressure type sliding bearing formed in the above and a metal lubricant which is supplied to the bearing gap and is at least liquid during operation. At least one of the portion and the surface portion of the fixed body is made of a hardened steel material.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. Reference numeral 11 denotes a vacuum vessel having a structure in which a large-diameter portion 11a and a small-diameter portion 11b are continuous.
The cylindrical rotating body 12 is provided in the internal space of the small diameter portion 11b.
Is arranged.

The rotating body 12 comprises an outer cylinder 13, an intermediate cylinder 14, and a bottomed inner cylinder 15 provided coaxially with each other. The outer cylinder 13 is made of copper, and is fitted around the outer periphery of an intermediate cylinder 14 made of iron. Intermediate cylinder 1
A shaft 16 protrudes from 4, and an anode target 17 is fixed to the shaft 16 with screws 18.

The inner cylinder 15 is fitted inside the intermediate cylinder 14 with a heat insulating gap 19 therebetween. The inner surface of the inner cylinder 15 forms a bearing surface for a plain bearing. Further, four small projections 20 are provided on the outer periphery of the upper end of the inner cylinder 15. These projections 20 are in contact with the inner peripheral wall of the intermediate cylinder 14 and maintain the insulating gap 19, while at the same time keeping the two cylinders in a precise coaxial positional relationship. The inner cylinder 15 is brazed to the lower end 21 of the intermediate cylinder 14 in the drawing, and is partially connected.

The outer cylinder 13 and the intermediate cylinder 14,
A disk-shaped opening closing body 22 is fixed to a lower end of the rotating body 12 provided with each part of the inner cylinder 15, in this case, a lower end of the inner cylinder 15.

A cylindrical fixed body 23 is provided inside the rotating body 12.
Are inserted and fitted. On the surface of the fixed body 23, the dynamic pressure sliding bearings shown in the above-mentioned publications are formed. For example, two radial slide bearings 24a and 24b are formed on the outer peripheral portion of the fixed body 23 at positions separated in the rotation axis direction. Each of these radial plain bearings 24a and 24b is formed by a spiral groove having a herringbone pattern. Also, the rotating body 1 is provided on the upper and lower two end faces of the fixed body 23.
Thrust slide bearings 25a, 25b
Are formed. These are constituted by spiral grooves having a circular herringbone pattern.

A bearing gap of about 20 μm is maintained between the bearing surfaces of the rotating body 12 and the fixed body 23 during operation. In addition, the bearing surface of the rotating body 12 close to the bearing surface of the fixed body 23 in which the spiral groove is formed may be a smooth surface, or a spiral groove may be formed as necessary. And
A liquid metal lubricant made of a Ga-In-Sn alloy which is liquid during operation is supplied to the inside of the spiral groove forming the dynamic pressure sliding bearing between the rotating body 12 and the fixed body 23 and the bearing gap between the two.

The fixed body 2 in which the spiral groove is formed
The bearing surface portion 3 is made of a hardened steel material. In this case, the entire fixing body 23 may be made of a quenched steel material, or a spiral groove is formed on the surface of a quenched cylindrical steel material, and then the surface of the cylindrical fixing body is formed. You may make it fit a cylindrical steel material in a part.

The lower part of the fixed body 23 in the figure is an anode support part 23a. The anode support portion 23a is airtightly joined to the small-diameter portion 11b of the glass vacuum vessel 11 via an auxiliary metal ring 26 and thin seal rings 27 and 28, respectively.

A cathode structure 29 is disposed in front of the anode target 18 and a small-diameter portion 1 of the vacuum vessel 11 is provided.
A stator 30 having an electromagnetic coil is arranged outside 1b.

The stator 30 generates a rotating magnetic field and rotates the rotating anode target 17 in the direction of arrow P at high speed. In this state, the rotating anode target 17 is irradiated with an electron beam from the cathode assembly 29 to generate X-rays. The X-rays generated by the rotating anode target 11 pass through the large diameter portion 11 of the vacuum vessel 11.
The light is taken out from the X-ray emission window 31 provided at a.

The rotating body of the above-mentioned rotary anode type X-ray tube has a cross section taken along line 2-2 in FIG. 1, for example, and has a structure as shown in FIG. An outer cylinder 13, an intermediate cylinder 14, and an inner cylinder 15 are provided coaxially, and four small protrusions 2 provided on the outer periphery of the upper end of the inner cylinder 15.
0 is in contact with the inner peripheral wall of the intermediate cylinder 14.

In the above embodiment, the bearing surface portion of the fixed body having the spiral groove is formed of a hardened steel material. However, in this case, the bearing surface portion of the rotating body that maintains a bearing gap with the bearing surface of the fixed body may be made of a hardened steel material.
The bearing surfaces of both the fixed body and the rotating body may be made of hardened steel material.

In the above-described embodiment, one of the bearing surfaces of the fixed body and the rotating body, or both of the bearing surfaces, are made of a hardened steel material such as stainless steel. However, instead of quenched steel, the symbols SKS and SK standardized in JIS G4404
D, SKT type alloy tool steel or JIS G4403
The same effect can be obtained by using a high-speed tool steel of symbol SKH standardized in JIS or carbon tool steel of symbols SK1 to SK7 standardized in JIS G4401.

In the above embodiment, the rotating body has a cylindrical shape, and the fixed body is fitted inside the rotating body. However, on the contrary, it is also possible to adopt a structure in which the fixed body is cylindrical and the rotating body fits inside the fixed body.

As described above, in the present invention, the bearing surfaces of the fixed body and the rotating body are made of hardened steel, tool steel, and high-speed tool steel. In this case, it is possible to manufacture a rotating anode type X-ray tube that maintains a stable bearing operation for a long time. Further, machining becomes easy and a low-cost rotating anode X-ray tube can be realized.

The portion made of steel, tool steel, or high-speed tool steel may be only the surface of the bearing surface of the fixed body or the rotating body. In this case, the thickness of the portion made of a steel material or the like can be set as appropriate according to use conditions and the like.

[0025]

According to the present invention, a rotating anode X-ray tube in which the bearing portion operates stably can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a cross section of a rotating body used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Vacuum container 11a ... Large diameter part of a vacuum container 11b ... Small diameter part of a vacuum container 12 ... Rotating body 13 ... Outer cylinder 14 ... Intermediate cylinder 15 ... Inner cylinder 16 ... Shaft 17 ... Anode target 18 ... Nut 19 ... Heat insulation gap DESCRIPTION OF SYMBOLS 20 ... Projection 21 ... Lower end part of an intermediate cylinder 22 ... Opening closure 23 ... Fixed body 23a ... Anode support part of fixed body 24a, 24b ... Radial bearing 25a, 25b ... Thrust bearing 26 ... Auxiliary metal ring 27, 28 ... Thin wall Seal ring 29: cathode assembly 30: stator

Claims (3)

[Claims] A rotating body to which an anode target is connected;
A fixed body fitted to the rotating body via a bearing gap, a hydrodynamic sliding bearing formed between the rotating body and the fixed body, and a liquid which is supplied at least to the bearing gap during operation. In a rotary anode X-ray tube provided with a certain metal lubricant, at least one of a surface portion of the rotating body and a surface portion of the fixed body forming the bearing gap is made of a hardened steel material. A rotating anode type X-ray tube characterized by the above-mentioned. 2. A rotating anode type X-ray tube according to claim 1, wherein at least one of a surface portion of the rotating body and a surface portion of the fixed body forming the bearing gap is made of tool steel. 3. The rotary anode type X-ray tube according to claim 1, wherein at least one of the surface portion of the rotating body and the surface portion of the fixed body forming the bearing gap is made of high-speed tool steel. .