JPH10106461A - Rotary anode type x-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long life rotary anode type X-ray tube in which stable rotary performance can be maintained for a long period. SOLUTION: A spindle 16b which accompanying rotates together with a target is supported via ball bearings 17, 16 by a cylindrical holder 30. The inner rings 17a, 18a of the ball bearings 17, 18 are fixed to the outer periphery of the spindle 16b, and outer rings 17b, 18b can move within a certain range in a shaft direction against the inner periphery of the holder 30. Solid lubricant- made lubricating film 40 intervenes between the inner rings 17a, 18a and the outer rings 17b, 18b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating anode type X-ray tube used in a medical X-ray diagnostic apparatus and the like, and to an improved support structure for the anode.

[0002]

2. Description of the Related Art A rotating anode type X-ray tube having a cylindrical holder for supporting, via a rolling bearing, a spindle rotating together with a target is used. When this X-ray tube is used in a medical X-ray diagnostic apparatus or the like,
The posture is changed so as to face various directions in order to change the X-ray irradiation direction. The direction of the own weight of the anode applied to the rolling bearing changes with the change in the attitude. In order to prevent the rotation of the rolling bearing from being hindered by the change in the direction in which the load is applied, the outer ring of the rolling bearing can be moved within a certain range in the axial direction with respect to the inner circumference of the holder. Is reduced.

[0003]

In a structure in which the outer ring is movable in a predetermined range in the axial direction with respect to the inner periphery of the holder, the thermal expansion difference between the outer ring and the holder, and the lack of perfect circular accuracy of the inner periphery of the holder. For example, the outer ring may bite into the holder, preventing smooth movement. for that reason,
An abnormal load acts on the rolling element of the rolling bearing due to a change in the position of the X-ray tube, and the rolling element cannot slide on a predetermined track surface, causing a problem that the rotation noise changes. If the rolling bearing is continuously used in this state, the lubricating layer on the surface of the rolling element of the rolling bearing is damaged, the rotation noise is increased, the rotation performance is reduced, and the life is shortened.

An object of the present invention is to provide a rotating anode type X-ray tube which can solve the above problems.

[0005]

According to the present invention, there is provided a cylindrical holder for supporting, via a rolling bearing, a spindle which rotates together with a target, and the rolling bearing has an inner ring fixed to the outer periphery of the spindle. And a rotating anode type X-ray tube having an outer ring movable in a predetermined range in the axial direction with respect to the inner periphery of the holder, wherein lubrication made of solid lubricant is provided between the inner periphery of the holder and the outer periphery of the outer ring. It is characterized in that a film is interposed.

According to the structure of the present invention, the friction between the outer ring of the rolling bearing and the holder is reduced by the lubricating film, the galling between the two is eliminated, and the outer ring is moved to the holder in accordance with the load change acting on the rolling bearing. It can be moved smoothly along the inner peripheral surface of the. As a result, the rolling element of the rolling bearing slides smoothly on a predetermined raceway surface, prevents a change in the anode rotation sound due to a change in the position of the X-ray tube, and damages the lubricating layer on the surface of the rolling element, thereby causing rotation. To prevent the sound from becoming too loud,
The rotation performance of the anode can be stabilized for a long time, and the life can be improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

A rotating anode type X-ray tube 1 shown in FIG. 1 comprises a focusing electrode 11, an anode 12, the focusing electrode 11 and the anode 1.
2 and a glass bulb 13 covering the same. The focusing electrode 11 is fixed to a glass bulb 13 and has a filament 14 that emits thermoelectrons when a high voltage is applied. The anode 12 has a disk-shaped target 15 facing the filament 14, and a rotor 16, which is rotatably attached to the target 15 so as to be coaxial therewith.
And a holder 30 for supporting the rotor 16 so as to be relatively rotatable via rolling bearings 17 and 18 formed of a pair of deep groove ball bearings. The holder 30 is fixed to the glass bulb 13.

As shown in FIG. 2, the rotor 16 has a cylindrical rotor body 16a having one end opened, and a support shaft 16b fixed to the inner end of the rotor body 16a in a cantilever manner.
And The double rolling bearing 1 is mounted on the support shaft 16b.
7, 18 and the cylindrical inner ring side spacer 19 are fitted. Nut 2 screwed to the tip of the support shaft 16b
0, the inner rings 17a, 18 of the two rolling bearings 17, 18
a and the inner ring side spacer 19 are formed by a step 1 on the outer periphery of the support shaft 16b.
6b '. Thereby, both inner rings 17a,
18a is fixed to the support shaft 16b. A compression coil spring 21 is fitted on the outer periphery of the inner ring side spacer 19. The spring 21 is provided with outer races 17 b, 1 of the two rolling bearings 17, 18.
The preload for preventing rattling is applied to the rolling bearings 17 and 18 by individually applying elastic force to the rolling bearings 8b via the outer ring side spacers 22a and 22b.

The holder 30 has a cylindrical shape and has an inner periphery fitted to the outer periphery of the two rolling bearings 17 and 18 inside the rotor body 16a. As shown in FIG. 3, the inner circumference of the holder 30 and the two rolling bearings 17, 18
The lubricating film 40 is interposed between the outer races 17b and 18b of the holder 3 and the outer races 17b and 18b.
It can be moved axially with respect to 0. Target 1 above
A pin 31 screwed into the holder 30 from the radial direction is inserted into a through hole 22a 'formed along the radial direction on one outer ring side spacer 22b away from the outer ring 5. The diameter of the pin 31 is smaller than that of the through hole 22b '.
The axial movement of the b, 18b with respect to the holder 30 is restricted to a certain range.

The lubricating film 40 is made of a solid lubricating material capable of exhibiting good lubricity both in vacuum and in air. The lubricating film 40 is formed between the inner peripheral surface of the holder 30 and the outer ring 1.
7b and 18b can reduce the friction as compared with the case where they come into direct contact with the outer peripheral surface.
The outer peripheral surfaces of b and 18b are coated by vacuum deposition, sputtering, or the like. The vapor pressure of the lubricating film 40 is
It is preferably as low as possible in order to prevent a withstand voltage failure due to the degree of vacuum deterioration of the X-ray tube 1. In the manufacturing process of the X-ray tube 1, the rotor 16 is rotated in the air with respect to the holder 30 via the bearings 17 and 18 in order to adjust the dynamic balance of the anode 12. A material that does not lose its properties is preferable as the material of the lubricating film 40. Further, since the degassing step of the X-ray tube 1 is performed at a high temperature of about 350 ° C. to 400 ° C. in order to radiate the adsorbed gas of the components inside the tube, it evaporates at that temperature to evaporate the inside of the tube. A substance that does not lower the degree of vacuum is preferable as the material of the lubricating film 40. Therefore, as the material of the lubricating film 40, a solid lubricating material such as molybdenum disulfide or tungsten disulfide which has lubricity even in the air or in a vacuum and has a low vapor pressure is preferable. If the thickness of the lubricating film 40 is excessively large, a part of the lubricating film 40 falls off when the outer rings 17b, 18b are moved in the axial direction with respect to the holder 30, and this is lost.
Between the outer ring 17b and the holder 30 and the holder 30. If the outer ring 17b or 18b is too thin, it may be worn away and the effect cannot be obtained. .01 μm
It is preferably 0.1 μm.

According to the upper air configuration, the friction between the outer rings 17b, 18b and the holder 30 is reduced, the galling between them is eliminated, and the outer rings 17b, 18b are smoothly moved along the inner peripheral surface of the holder 30. Can be moved. As a result, the balls 17c, 18c of the two rolling bearings 17, 18 are smoothly slid on a predetermined track surface, and the balls 17c, 18c
It is possible to prevent the lubrication layer on the surface from being damaged and increase the rotational noise, and to stabilize the rotational performance of the anode 12 for a long period of time.

The present invention is not limited to the above embodiment. For example, the lubricating film 40 may be formed on the inner periphery of the holder 30 in contact with the bearing outer ring.

[0014]

According to the present invention, a long-life rotating anode X-ray tube capable of maintaining stable rotating performance over a long period of time can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a rotary anode type X-ray tube according to the present invention, a support shaft which rotates together with a target is supported by a cylindrical holder via a pair of ball bearings, and an inner ring of each ball bearing is in an axial direction. The outer ring of each ball bearing is fixed to the outer circumference of the support shaft at intervals, and the outer ring of each ball bearing can move axially with respect to the inner circumference of the holder.Each outer ring holds the ball of the ball bearing by the elasticity of the spring sandwiched by both outer rings. It is preferable that the inner ring is pressed against the inner ring from the axial direction, and a lubricating film made of a solid lubricant is interposed between the inner circumference of the holder and the outer circumference of each outer ring. Thus, the outer race can be moved in the axial direction in accordance with the change in the applied load while applying an appropriate preload to the two rolling bearings by the elastic force of the spring.

In the rotary anode type X-ray tube of the present invention, the lubricating film between the inner periphery of the holder and the outer periphery of the outer ring is formed of molybdenum or tungsten having low vapor pressure and lubricity even in air or vacuum. Composed of solid lubricants such as
It is preferable that the film thickness is 0.01 to 0.1 μm.
As a result, it is possible to prevent a withstand voltage failure due to the degree of vacuum deterioration of the X-ray tube and to reliably prevent the outer ring from galling on the holder.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rotating anode type X-ray tube according to an embodiment of the present invention.

FIG. 2 is a sectional view of an anode of a rotating anode type X-ray tube according to an embodiment of the present invention.

FIG. 3 is a sectional view of a main part of an anode of a rotary anode type X-ray tube according to an embodiment of the present invention.

[Explanation of symbols]

 15 Target 16b Support shaft 17, 18 Rolling bearing 17a, 18a Inner ring 17b, 18b Outer ring 30 Holder 40 Lubrication film

Claims (1)

[Claims] 1. A cylindrical holder for supporting, via a rolling bearing, a spindle that rotates together with a target, wherein the rolling bearing has an inner ring fixed to the outer periphery of the spindle and an inner ring of the holder. On the other hand, in a rotating anode type X-ray tube having an outer ring movable in a certain range in the axial direction, a lubricating film made of a solid lubricant is interposed between the inner periphery of the holder and the outer periphery of the outer ring. Characteristic rotating anode X-ray tube.