JPS593855A - Rotary anode x-ray tube - Google Patents

Abstract

PURPOSE:To provide a large-capacity X-ray tube which has a high load capacity as well as a high heat capacity and in which any crack breakdowns are prevented by increasing the mechanical strength of a rotor shaft which supports a target producing X-rays. CONSTITUTION:A surface intensified film 8 of over 10mum thickness formed by subjecting a highly heat-resisting metal such as tungsten to flame coating, is provided over the entire outer peripheral surface of a rotor shaft 3b. Here, the film 8 is formed by melting tungsten by plasmas before molten tungsten is sprayed over the outer peripheral surface of the rotor shaft 3b at high air pressure. According to such constitution, numberless cuts formed on the outer peripheral surface of the rotor shaft 3b are completely filled and the rotor shaft 3b entirely coated with the film 8 made of tungsten. As a result, concentrated stress developing in the cuts is alleviated, and any crack breakdowns can be positively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating anode X-ray tube (hereinafter referred to as an X-ray tube), and particularly to improving the strength of a rotor shaft portion that supports a target that generates X-rays.

In general, the anode portion of an X-ray tube has an anode structure as shown in a cross-sectional diagram of main parts in FIG. That is, in the figure, a rotary shaft 4 of a rotor section 3 is rotatably arranged at both ends of a fixed section 1 via a plurality of bearings 2. This rotating shaft 4 is attached to the main body of the rotor section 3 by a screw 5.
are integrally connected. Further, the main body of the rotor section 3 includes a cylindrical rotor body 3m made of a Cu material on which the fixing part 1 is installed horizontally, and a rotor shaft made of a M material integrally formed with the cylindrical rotor body 31. The rotating shaft 4 of the rotor portion 3 is fixed by a screw 5 to the bottom portion which is a connecting portion between the cylindrical body portion 3m and the rotor shaft portion 3b. Further, an umbrella-shaped target 6 that emits X-rays is held and fixed to the rotor shaft portion 3b by a hinge 7.

A high voltage is applied to the anode section of the X-ray tube configured in this manner at 1lJj with the cathode section (not shown), and high-speed electrons are ejected from the cathode section toward the umbrella-shaped target 6. A rotating magnetic field is generated from a stator (not shown), which has 9 turns around the 3 m rotor body to prevent melting of the Hatsei electron injection protrusion, to rotate the rotor section 3, and the umbrella-shaped target 6 is rotated at high speed to create an umbrella-shaped target. X-rays are emitted from the inclined surface of No.6.

However, the X-ray tube anode with the above-mentioned configuration cannot be used with an umbrella-shaped target 6 having a weight of 500 V or more when emitting X-rays.
Since the rotor shaft 3b is rotated at a high speed of approximately xooooorpm or more, excessive rotational stress is applied to the rotor shaft portion 3b, and further centrifugal force is applied when the X-ray tube is moved during rotation. On the other hand, the heat of the umbrella-shaped target 6 generated by the collision of high-speed electrons from the cathode section rises to about 800.degree. C. or higher in the rotor shaft section 3b. Therefore, during X-ray radiation, the strength of the rotor shaft portion 3b decreases significantly, to below about h (about 50 Kq/mm'') at room temperature.

Further, since the rotor shaft portion 3b is formed by cutting the M rod, its outer circumferential surface has countless minute cutting scratches. For this reason, this part has the above-mentioned rotational imaging, centrifugal force,
There were problems such as concentration of stress due to heat etc., which easily caused cracks and damage, impairing the rotation function and making it unusable. For this reason, large capacity X with large load capacity and heat capacity
Manufacturing wire tubes is limited by the mechanical strength mentioned above,
Therefore, it naturally had its limits.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to prevent crack damage by improving the mechanical strength of the rotor shaft, and to improve the load bearing capacity. The object of the present invention is to provide a large-capacity X-ray tube with a large heat capacity.

In order to achieve such an object, the present invention provides a surface reinforcement film made of a highly heat-resistant metal on the outer peripheral surface of the rotor shaft.

Embodiments of the present invention will be described in detail below using the drawings.

FIG. 2 is a cross-sectional configuration diagram of essential parts showing an example of an X-ray tube according to the present invention, and since the same symbols as in FIG. 1 represent the same elements, a description thereof will be omitted. In the same figure, about 10% of tungsten, for example, is coated on the entire outer peripheral surface of the rotor shaft 3b as a highly heat-resistant metal.
A surface reinforcement film 8 formed by thermal spraying to a thickness of 0 μm or more is provided. In this case, the surface reinforcement film 8 can be formed by melting tungsten with plasma and spraying it on the outer peripheral surface of the rotor shaft 3b under high air pressure.

According to such a configuration, the countless cutting scratches formed on the outer peripheral surface of the rotor shaft 3b are completely filled with the tungsten surface reinforcement film 8, and the upper surface thereof is completely covered and integrated. It turns out. As a result, concentrated stress occurring in the uneven portions is alleviated, and crack damage can be reliably prevented. In this case, it is clear from experiments that the mechanical strength of the rotor shaft 3b provided with the surface reinforcement film 8 can be improved by 1.3 to 1.7 times compared to the conventional product when the film thickness is about 10 μm. became.

In addition, in the above example, the case where tungsten was used as the highly heat-resistant metal was explained, but the present invention is not limited to this, and the same effect as described above can be obtained even if molybdenum is used. Needless to say.

As explained above, according to the present invention, it is possible to improve the mechanical strength of the rotor shaft supporting the target without increasing its thickness, thereby reliably preventing damage due to cracks. The present invention has an extremely excellent effect in that a large-capacity rotating anode X-ray tube can be obtained that can easily water a target with a large load capacity at high speed.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of an example of a conventional rotating anode X-ray tube, and FIG. 2 is a cross-sectional view of the main parts of an example of a rotary anode X-ray tube according to the present invention. 1@... fixed part, 2... bearing, 3... rotor part, 3a9, fist, rotor body, 3b... 0, rotor shaft part, 4... rotary shaft, 5...・・・Screw, 6・Temple...
Target, T...Natsuto, 8 fists...surface reinforced membrane. Figure 1 Figure 2

Claims (1)

[Claims] 1. A rotating anode
1. A rotating anode X-ray tube, characterized in that a surface-reinforced film made of a highly heat-resistant metal is provided on the outer peripheral surface of the rotor shaft. 2. The rotating anode X-ray tube according to claim 1, wherein the highly heat-resistant metal is tungsten.