JPS58189997A - Rotation anode x-ray tube apparatus - Google Patents

Abstract

PURPOSE:To provide stable rotation in all speed region by forming a support with a material having internal damping action in a region below a specified shearing elastic module when a bearing apparatus of a rotation anode X-ray tube is supported in a sealed container. CONSTITUTION:An X-ray tube obtained by sealing a rotor having an anode target 2 and a cathode 1 in a vaccum container 12 is accommodated in a sealed container 8 which has a rotation magnetic field generation apparatus 7 and is filled with oil 17 to form a rotation anode X-ray tube. A bearing box 6 consisted by supporting the rotor 3 with a ball bearing 5 is elastically supported in a frame 13 of the box 8 by supporting a rubber ring 10 having internal damping action in a region of a shearing elastic module of 30kg/cm<2> or less with supports 9a and 9b. Therefore, play vibration of the ball bearing 5 caused by large bearing gap formed in consideration of heat expansion is effectively absorbed, and rotation can be operated with stable vibration performance up to high speed region.

Description

[Detailed description of the invention] The present invention relates to improvements in rotating anode X-ray tube devices.

2. Description of the Related Art Conventionally, a rotating anode X-ray tube device has been used in which a vacuum container housing a cathode body and a rotating anode is disposed within a sealed container filled with oil. In this rotating anode X-ray tube device, the rotating anode is rotatably supported by ball bearings.
Since it rotates at ~9000 rpm, a high voltage is applied between the cathode body and the rotating anode to generate X-rays. For this reason,
The rotating ls pole is heated to an average temperature of about 1000 t:' by electron beam radiation from the cathode body, and the ball bearing supporting it reaches a temperature of about 500 C. Therefore, in consideration of thermal expansion, ball bearings are used with a bearing clearance of approximately 50 μm (ti5 to 20 μm for ball bearings of general rotating machines).

On the other hand, when operated at room temperature, the ball bearing has a large clearance, which not only causes the rotating anode to be in an unstable rotational vibration state, but also makes the rolling noise inherent to the ball bearing large.

Particularly in critical speed ranges, the vibrations acting on the ball bearings increase, causing early damage and often resulting in louder rotational noise, rendering them unusable. Furthermore, as damage to the ball bearing progresses, the vibration becomes more unstable and the image quality of the X-carp may deteriorate. Therefore, as a method for reducing the dynamic load acting on the ball bearing, a structural method has been proposed in which the support rigidity of the ball bearing is lowered and the critical speed is set in a low speed range. This bearing support method is effective in reducing dynamic loads due to mass imbalance acting on the ball bearings, but the ball bearings are too weak! There is no effect in preventing rattling vibrations generated by grooves, and even if the support rigidity of the ball bearing is set low in the high-speed range, the rotating part l rotates in an unstable rotational vibration state, making a lot of rotation noise, making it difficult to improve image quality. I don't like this book.

The present invention has been made in an attempt to improve the above-mentioned drawbacks, and its purpose is to provide a long-life rotating anode X-ray that has stable rotational vibration characteristics in the entire speed range and provides clear images. is in providing pipe equipment.

That is, the features of the present invention include an anode target disposed opposite to a cathode body, a rotating member integrally configured with the anode target, a bearing device that rotatably supports this rotating member, a part of this bearing device, and a container. A rotating anode X-ray tube with the above-mentioned components covered and evacuated, a rotating anode X-ray tube supported in a sealed container, a magnetic field generating device for the rotating member provided in the sealed container, and an L-shaped rotating anode. In the X-ray tube device, the bearing device is elastically supported in a closed container via a support, and
This support is used in a rotating anode X-ray tube device using a material having a shear elastic modulus of 30 Kg/cm or less and an internal damping effect.

What follows is the implementation of the present invention? 1" will be explained with reference to the drawings.

Figure 1 shows a rotating anode Xa tube loading according to the present invention.

To outline the overall configuration with reference to FIG. 1, an anode target 2 serving as an anode body is fastened to one end of a drive motor rotor 3 serving as a rotating member, and a shaft 4 is coupled to the other end. It is rotatably supported by a ball eave support 5 of 21- which is provided and arranged. The ball bearing 5 is mounted on a bearing box 6, and a cathode body 1 is arranged with a part of the bearing box 6 and a tube 12 facing the Km target 2 and the anode target 2.
Also, parts such as the motor rotor 3, shaft 4, ball shaft father 5, etc.
They are stacked in nine shapes to form an X-ray tube. Further, this XM tube is sealed in an airtight container 8 with insulating oil 17 sealed therein.

That is, a frame 13 that supports the ninth rotating magnetic field generating device #t7 that drives the motor rotor 3 is provided at one end of the closed container 12, and a support ring 9a is fixed to the frame 13 by a presser ring 11, and a support member 9b and a support ring 9a are fixed to the frame 13 by a holding ring 11. Nine supports made of rubber rings 10 are interposed between rings 91, and one end of the X-ray tube is elastically supported. (9) The other end of the Xa tube is supported by the closed container 8 via a rubber ring 14. Note that 15a and 15bl<lead wires, and 16 is a lead wire connector. The rubber ring 10 has a shear modulus of 3
0 k / 1" or less. 9. Rounding K that exhibits the vibration damping effect more effectively has a shear modulus of elasticity of 5 to 10.
/cm'' material is preferable, and since the material is rubber, it has an internal damping effect.

In the above configuration, the rotating magnetic field generator f, 7 generates a motor f.
It:1-fi3 is rotated at a high speed of 3000 to 9000 rpm, and a high voltage is applied between the cathode body 1 and the anode target 2 to generate X-rays in the direction of the arrow in the figure.

At this time, the average temperature of the anode target 2 is 100 OC to 1200 ℃ due to the electron beam radiation of the cathode body 1, so the ball bearing 5 is heated to about 50 Or by thermal conduction. Therefore, as mentioned above, considering thermal expansion, the bearing clearance is approximately 50.
μm ball bearings are used.

Therefore, when rotating at the initial stage of rotation, that is, at room temperature, the clearance between the ball bearings is large, causing rattling vibrations, and the 20th fk:m motion of the target is large. However, the rotational vibration of the rotating anode body is not only absorbed by the rubber rings 10 and 14, but also because the rubber ring has an extremely small elastic modulus, it is possible to reduce the critical speed of the supporting portion to 11,000 to 2,000 rpm. In addition, the width of the vibration axis in the critical speed region due to bending of the shaft 4 is also changed by using the rubber ring lO and 14 years old, so the vibration due to the mass unbalance of the U rolling element in the critical speed region of the shaft 4 is The target load is @ destroyed, so it's a ball! Δ, the dynamic load h is not so large that it acts on the l1lIi receiver 5. -! In addition, the backlash vibration caused by the clearance of the ball bearing 5 is effectively shaken out by the rubber ring 10. When the X-ray cabinet is supported by a member having a large internal damping effect as described above, not only the vibration absorption effect but also the rotation noise is reduced.

In order to confirm the effects of the present structure described above, we compared the structure supported by a rubber ring and the gold lAl1 which has almost the same support rigidity as the rubber ring! The zero vibration in the radial direction of the anode target 2 was actually measured for the support structure using the support body. Fifth
The figure shows a comparison of actual measurements of the rotational vibration of the Me metal 2. Since the vibration is measured from the stationary side, the damping effect is shown in figure 0, which shows the combined vibration of the anode target 2 and the bearing box 6. Structure (I), which was supported by a metal support without a metal support, showed unstable vibrations from low speed to high speed, and not only loud rotation noise but also irregular noise was generated.

On the other hand, it was found that the support structure (II) according to the present invention has a small amplitude when passing through a critical speed, exhibits stable vibration characteristics up to a high speed range, and is also effective in reducing the rotational noise of the ball bearing. Furthermore, it was confirmed from the results that even if the support rigidity of the rotating system is set low, it has almost no effect on vibration absorption.

2 to 4 show other embodiments of the present invention. In FIG. 2, a rubber O-ring 20 is attached to a support member 9b fastened to a bearing box 6, and a support ring 9alC is assembled. It has a similar structure. Reference numeral 18 denotes a lock pin of the support member 9b, which is fixed to the support ring 9a via a presser fitting 21. In this embodiment, insulating oil is present in the cylindrical gap 19 formed between the support/glue 9a and the support member 9b, so that when the support member 9b vibrates in the radial direction, it is damped in the cylindrical gap 19 due to the squeezing effect of the oil film. The effect is exerted. The smaller the dimensions of this cylindrical gap 119, the greater the effect, and the structure shown in FIG. 2 can have a greater damping effect than the embodiment shown in FIG.

Fig. 3 has the same configuration as Fig. 2, but the center part of the support member 9b is made into a spherical shape with a radius R relative to the shaft center, and this part is guided in contact with the support ring 9a, and the spherical part is used as a fulcrum to form a bearing box. This support structure is designed to prevent the load of the X-ray tube from directly acting on the rubber 01J ring 20. This is because materials with a low shear modulus of elasticity have the disadvantage of causing permanent deformation if a load is applied over a long period of time, and this permanent deformation may cause X-ray focus to shift. This has the effect of preventing focus shift of X#iI.

The embodiments shown in FIGS. 1 to 3 have a structure in which the rubber O-ring 20 is elastically deformed in a direction perpendicular to the shaft center to absorb vibrations, but in the embodiment shown in FIG. 4, a rubber ring 22 is attached to the support ring 9a. It has a structure in which the rubber ring 22 is attached and deformed in the axial direction to absorb vibration.

Note that 23 and 24 are presser fittings, and 25 is a rotation stopper pin.

In each embodiment of the present invention, a rubber member is used as the support, but any material having a low elastic modulus and an internal damping effect, such as nylon or vinyl, may of course be used.

According to the present invention, the vibration of the rotating anode X-ray tube device is effectively absorbed and the rotation noise of the bearing is reduced, so that it is possible to obtain a single image with stable rotational vibration characteristics and good image quality. .

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a rotating anode X-ray tube device according to the present invention, FIGS. 2 to 4 are partial cross-sectional views of each embodiment of an X-ray tube fixing part according to the present invention, and FIG. FIG. 2 is an explanatory diagram showing actual measurement results.

Claims (1)

[Claims] 1. An anode target disposed opposite to the cathode body, a rotating member integrated with the anode target, a bearing device that rotatably supports this rotating member, a part of this bearing device, and a container to form the above-mentioned constituent members. Rotating anode X configured in a rectangular vacuum
In a rotating anode X-ray tube device comprising a ray tube, a rotating anode X-ray tube supported in a closed container, and a magnetic field generator of a rotating member provided in the closed container, the bearing device is connected to the rotary anode X-ray tube through a support. A rotary anode
wire tube device.