JPS60211750A - Rotary anode type x-ray tube - Google Patents

Abstract

PURPOSE:To obtain a stable ball bearing with long life by coating balls of a ball bearing with Ag films while forming Pb films on said ball and on either one of the inner and outer races. CONSTITUTION:A ball bearing consists of an inner race 18, an outer race 19 and plural balls 20 positioned between both of them. The ball 20 is made of a heat- resisting alloy having Fe as a base material, while its surface is coated with a Cu film 21, an Ag film 22 and a Pb film by turns. Further, the Pb films 24 and 25 are formed on each rolling surface of the inner race 18 and the outer race 19 respectively. The Ag film 22 showing good lubricity in high temperature and a high vacuum as well as the Pb films 23, 24 and 25 protecting said Ag film 22 so that it may not deteriorate when rotating in the air are used for lubricating materials, thus being able to obtain the stabilization and a long life of the ball bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rotating anode type X-ray tube, and particularly to improvements in its rotation mechanism.

[Technical background of the invention]

Generally, X-ray tubes are used for medical purposes, for example, for X-ray diagnosis, and in cases such as gastric examination, an X-ray tube as shown in FIG. 1 has conventionally been used. This X-ray tube is of the so-called rotating anode type, in which an eccentric cathode 2 and a substantially umbrella-shaped anode 3 are disposed facing each other in a vacuum envelope 1, and the anode target 3 is rotated by a rotating mechanism. 4 and is rotatable. Further, a stator (not shown) is disposed outside the vacuum envelope 1 in correspondence with the rotating mechanism 4, and drives the rotating mechanism 4.

In this type of rotary homopolar mX-ray tube, the conventional anode target and rotation mechanism are shown in detail as shown in FIG. A substantially umbrella-shaped anode target 3 is fixed to the support column 6 by a nut 7, which is coaxially and integrally protruded.

A rotary shaft 9 is fixed coaxially to the inside of the cylinder 8. In this case, a disk 10 is integrally formed at one end of the rotating shaft 9, and this disk 10 is fixed to the inner surface of the lid portion of the cylinder 8 with screws 11. Further, a cylindrical anode fixing base 4 is inserted between the rotating shaft 9 and the cylinder 80, and the anode fixing base 14 is fixed to the vacuum envelope 1 (see FIG. 1). . Two sets of ball bearings 12.13 are interposed between the anode fixed base 14 and the rotating shaft 9, and the ball bearings 1 and 13 are kept at a predetermined distance by a cylindrical spacer 15.16. It is supported and fixed by a nut 17. Further, each of the ball bearings 12 and 13 has an inner race 18, an outer race 19, and 1? The inner ring race 18 is fixed to the rotating shaft 9, and the outer ring race 19 is fixed to the anode fixing base 14.

Now, in the conventional X-ray tube as mentioned above, the temperature of the ball bearing 1 during operation reaches 200 to 400 C due to heat conduction from the high temperature anode target 3, so it is necessary to maintain good lubrication. Therefore, the quality of lubrication has a great influence on the performance of the rotating mechanism 1.

In this case, Au is used as a lubricant that can withstand high temperatures and high vacuum.
, Ag, Pb + MoS2, etc. have been used, but these have not been satisfactory due to variations in life.

Therefore, the inventor developed the high input power required for recent X-ray tubes.
Ag has excellent heat resistance and high surface pressure resistance as a lubricant due to high loads.
We have found that the thin film is good. The ion silating method is most suitable for forming this Ag thin film. or,
Between the known thin Ag thin film and the base material Fe@, Ni
It is further effective to increase the strength by attaching an interlayer film such as Cu or the like.

This Ag thin film may be applied to each of the transfer surfaces of the inner and outer race of the goal bearing and the sole surface, or it may be applied only to the ball surface. The point is that it should be between the contact surfaces.

However, when evaluating X-ray tubes with the above-mentioned lubricated surface, it was found that there were variations in rotational characteristics and service life. As a result of the investigation, it was found that although Ag has a strong adhesion force in negative air and inherently has a stable and long lubrication life, during the X-ray tube manufacturing process, when the balance of the rotating body is adjusted, Ag is left in the air for a long time. It was found that the film was no longer stable and uniform as it was rotated (for example, for several minutes in some cases, and for several tens of minutes in cases where the readjustment was repeated).

This is thought to be due to oxidation, peeling, etc. of the Ag sheared surface due to rotation in the air.

This means that in beer bearings using a retainer, the retainer... This is particularly noticeable between the two wheels, and for this reason, although ball bearings using cages have good rotational performance such as rotational accuracy and rotational noise, their lifespans vary, causing poor Ml/i. Ta.

[Purpose of the invention]

It is an object of this invention to provide a rotating anode x-ray tube with a stable and long-life sol bearing.

[Summary of the invention]

The first invention is a rotating anode type X-ray tube in which the nose of the pole bearing is coated with an Ag film as a lubricant, and the goal and at least one of the inner and outer races are coated with a Pb film.

The second invention is that an Ag film is formed on each of the transfer surfaces of the inner and outer races in a ball bearing, and each race, ? - This is a rotating anode type X-ray tube in which a Pb film is formed on either side of the tube.

The third invention is to add Ag to the galley in the sol bearing.
This is a rotating anode type X-ray tube that is coated with a Pb film and has a Pb film formed on at least one of the pole, inner/outer race, and retainer.

゛ [Embodiment of the first invention] In order to solve the above-mentioned problems, this invention improves the goal bearing, and only the sol bearing will be explained.

That is, the same parts as in the conventional example (Fig. 2) are given the same reference numerals.The goal bearing in the rotating anode type X-ray tube of the first invention is constructed as shown in Fig. 3, and the inner ring race 1
8. It consists of an outer race 19 and a plurality of soles 20 located between the two.

In this case, the 3;-rule 20 is made of a heat-resistant alloy based on Fe, and the surface thereof is coated with a Cu film 21 and an Ag film 22.
, Pb film 23 are sequentially coated.

The Cu film 21 has a thickness of about 0.2 μm to improve adhesion between Ag and Fe, and is not necessarily thick. The thickness of the Ag film 22 is approximately 1 μm, and the thickness of the PB film 23 is approximately 1 μm.

Further, Pb films 24 and 25 are formed on each rolling surface of the inner race 18 and the outer race 19, respectively.

Incidentally, each of the above films can be formed by a well-known method such as ion blating. In addition, PBA lubricant has a high rate of loss from transfer surfaces due to evaporation during use at high temperatures, but its lubricating performance at low temperatures and in air is superior to Ag in that its rotational torque is small.

In addition, in this embodiment, the sole 20 and the inner/outer race 1
Pb film is formed in all of 8.19, but Pb
The film may be formed only on one of the poles 20, the inner race 18, and the outer race 19.

Now, during the manufacturing process of a rotating anode type X-ray tube using a goal bearing as described above, when adjusting the balance of the rotating material in the air, the soft PB films 23 and 24 are used as well as the Ag film 22.
．． 25 acts as a lubricant, and during actual use, the PB film 23, 24.25 primarily acts as a lubricant initially in vacuum, and even if the PB film 23, 24.25 is gradually lost, the underlying Ag Both membranes 22 act as long-term lubricants. In this way, the lubrication performance of the bearing is not impaired even if the bearing is rotated at high speed for a relatively long period of time in air. This is p
The lubricating performance of the b films 23, 24, and 26 shows very little deterioration when rotated in air, and this is considered to be effective. Although some Ag and PB were mixed during use, no adverse effects were found in the test drive results.

[Effects of the first invention] According to the first invention, the ball bearing is provided with an Ag film 22 that exhibits good lubricity at high temperatures and in a high vacuum, and that the Ag film 22 is prevented from deteriorating during rotation in air. protect this p
Since the b films 23, 24, and 25 were used as the lubricating phase, it was possible to extend the life and stabilize the goal bearing.

That is, the conventional problem of the Ag lubricant peeling off when balancing the rotation in the air has been eliminated, and the noise has also been reduced.

[Embodiment of the second invention] The gear bearing in the rotating anode type X-ray tube of the second invention is constructed as shown in FIG.
8. The outer race 19 and the plurality of parts located between the two.
It consists of 20 files.

In this case, the tube 20 is made of a heat-resistant alloy based on Fe, as in the first invention, and furthermore, the surface is made of Cu.
A film 21, an Ag film 22, and a Pb film 23 are sequentially coated.

Further, the rolling surfaces of the inner race 18 and the outer race 19 are sequentially coated with Ag films 26, 27 and Pb films 24, 25, respectively.

In this embodiment, the goal 20 is coated with the Ag film 22, but the Ag film 22 may not be provided.

Furthermore, a Pb film is formed on both the ball 20 and the inner and outer races 18 and 19;
, may be formed only on either the inner race 18 or the outer race 19.

[Effects of the second invention] Exactly the same effects as in the case of the first invention described above can be obtained.

[Embodiment of the third invention] The goal bearing in the rotating anode type Xi tube of the third invention is constructed as shown in FIG.
8, an outer race 19, a plurality of balls 20 located between them, and retainers 28 and 29.

In this case, the sol 2o is made of a heat-resistant alloy made of Fe as a base material, as in the first invention, and furthermore, the surface is made of Cu.
A film 21, an Ag film 22, and a PB film 23 are sequentially coated.

Further, each rolling surface of the inner race 18 and the outer race 19,
And the inner surfaces of the retainers 28 and 29 are coated with pb, respectively.
Membranes 24.25, 30.31 are formed.

In this embodiment, the bar 20. Inner/outer race 18
．． A Pb film is formed on both the beer 20 and the circular race 18.
, the outer race 19, or the retainer 28, 29.

[Effects of the third invention] Exactly the same effects as in the case of the first invention can be obtained. Also, since this invention uses retainers 28 and 29,? - The arrangement and rotation accuracy of the wheels 20 are uniform.

What can be said in common with each of the above inventions is that the Pb film is mainly used to protect the tube during its rotation in the air and during its initial operation, so it may be extremely thin with a film thickness of 0.3 μm or less, but it is not heat resistant. Other than that, it is a good lubricant for X-ray tubes, so it doesn't matter how thick it is.

Moreover, the effect is not limited to Pb, but any metal that is softer than Ag can be used.

Moreover, although some effects can be recognized with a highly heat-resistant film such as Au instead of Ag, Ag is optimal.

Furthermore, the goal bearing in each of the above inventions is used at least on the high temperature side near the anode target 3, and on the low temperature side away from the anode target 3, it is practical to use a conventional goal bearing with a PB lubricant added. It has sufficient effect.

Further, since the rotary anode type X-ray tube of the present invention has the same structure as the conventional example (FIG. 2) except for the above-mentioned ball bearings, detailed explanation will be omitted.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a commonly used rotating anode type X-ray tube, Fig. 2 is a sectional view showing the vicinity of the conventional X-ray tube 01 rotation mechanism, and Figs. ．． Second. Main parts of the rotating anode type X-ray tube according to an embodiment of the third invention (
FIG. 3...Anode targut, 6...Support column, 8...Rotating cylinder, 9...Rotating shaft, 12.13...Ball bearing, 14...Anode fixed base, 18...Inner ring Race, 19...Outer race, 20...e-le, 21.
・・Cu1li, 22.26.27・Age, 23,2
4,25°30.31...Pb film, j! 8.29...
・Retainer. Applicant's agent Patent attorney Takehiko Suzue Figure 2 ετ Figure 4

Claims (1)

[Claims] (]) A rotating cylinder to which an anode TADAT is fixed, a rotating shaft coaxially fixed to the inside of this cylinder, and a cylindrical member disposed between this rotating shaft and the cylinder. In a rotating anode type X-ray tube equipped with an anode fixed base and a single bearing consisting of an inner race, an outer race, and a ball interposed between the anode fixation base and the rotating shaft, the sol includes the following: Ag film is coated and the yl? - A rotating anode type X-ray tube, characterized in that a PB film is formed on at least one of the inner race and the outer race. (2) a rotating cylinder to which an anode target is fixed; a rotating shaft coaxially fixed to the inside of the cylinder; a cylindrical anode fixing base disposed between the rotating shaft and the cylinder; In a rotating anode type X-ray tube equipped with an inner race, an outer race, and a Beer bearing made of sol interposed between the anode fixed base and the rotating shaft, an Ag film is provided on each of the inner race and the outer race. 1. A rotating anode type X-ray tube, characterized in that a PB film is formed on at least one of the inner race, the outer race, and the above-mentioned rings. (3) The rotating anode X-ray tube according to claim 2, wherein the ball is coated with an Ag film. (4) a rotating cylinder to which an anode target is fixed; a rotating shaft coaxially fixed to the inside of the cylinder; a cylindrical anode fixing base disposed between the rotating shaft and the cylinder; A rotating anode X-ray tube comprising an inner race, an outer race, a retainer, and a ball bearing consisting of balls, which are interposed between the anode fixed base and the rotating shaft,
A rotary anode type
wire tube.