JPH0375977B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating anode for an X-ray tube in which the fixation between a target and a column is strengthened.

FIG. 1 shows a rotating anode of a conventional X-ray tube, in which 1 is a target plate, 2 is a column, 3 is a nut, 4 is a rotor, 5 is a fixed part, 6 is a sealing ring, 7 is a detent boss, and 8 is a rotary anode. It's a spit. The target plate 1 is driven via the column 2 by a rotor 4, typically at 3,000 to 10,000 rpm. A stator (not shown) for generating a rotating magnetic field is arranged outside the valve around the rotor 4. The target plate 1 has a large diameter and is usually made of tungsten or molybdenum, which has a large specific gravity.
Since it is rotated at high speed, the entire rotating section consisting of the target plate 1, support column 2, and rotor 4 is adjusted to ensure good dynamic engagement during assembly. Since it is particularly important to fix the target plate and the column, in the illustrated example, a detent boss 7 is provided at the fitting part of the two, but another pin-shaped key may be fitted into the fitting part. . However, in reality, there is a gap, however small, between the hole in the target plate 1 and the column 2, so during operation,
The relative position of the target plate and the support column may be misaligned, and even the careful adjustment to ensure a good dynamic engagement during assembly may go awry. The larger and heavier the target and the higher the rotational speed, the greater the influence of misalignment due to target misalignment, the greater the noise and vibration during rotation, the greater the damage to the rotating parts, and the shorter the life of the target. In the case shown in FIG. 1, an eccentric detent boss is purposely provided, and keys in other cases are also inconvenient for achieving precise engagement. Therefore, engagement adjustment work is also necessary in this respect. These things have some effect and are useful for preventing rotation, but they are powerless to maintain a good engagement condition. In normal cases, brazing or welding, which is a general method of joining metals, can be applied, but since the target plate becomes hot when X-rays are generated, brazing is not suitable, and welding is not suitable for the target plate. This is difficult to implement because the members are high melting point metals such as tungsten and molybdenum.

An object of the present invention is to provide a rotating anode in which a target plate and a support column are firmly joined and the state adjusted to achieve dynamic engagement during assembly continues even during subsequent use.

In order to achieve the above object, in the present invention,
An intermediate ring made of the same type of heat-resistant metal as these members and having a density of 90 to 97% of the true specific gravity of the metal was inserted between the target plate and the support and fixed by tightening. Currently, molybdenum or its alloys are mainly used for the strut material, and in the case of large-capacity tubes, the target plate is often made of molybdenum and only the parts that become particularly hot when struck by the electron beam are coated with tungsten. Tungsten and molybdenum are produced by powder metallurgy, as is well known. The target plate, pillars, etc. are made by forging sintered ingots into a dense structure having a specific gravity almost equal to the true specific gravity. Therefore, the specific gravity of the intermediate ring (90 to 97% of the true specific gravity)
density) for tungsten or molybdenum,
It can be obtained in a sintered or slightly forged state.

FIG. 2 shows a main part of an embodiment of the present invention. Reference numeral 9 denotes a washer-shaped intermediate ring according to the present invention inserted between the target plate 1 and the collar 8 of the support column 2. FIG. In such a rotating anode, the target plate 1 and the column 2
has a dense structure equal to its true specific gravity, whereas the intermediate ring 9 has not reached its true specific gravity and is not dense, so there are When the mutual contact surfaces between the two reach a considerable high temperature, even if the temperature is well below the so-called melting point, the contact surfaces will move from the denser target plate 1 or column 2 to the less dense intermediate ring 9. The metal particles are transferred so as to alleviate the density difference, and the structure is unified. As a result, the intermediate ring 9 and the portions of the target plate 1 and support column 2 that were in contact with it become connected and do not move relative to each other. This is the backbone of the present invention. Therefore, unlike in the past, even if a good engagement is achieved through adjustment during assembly, there will be no possibility that the engagement will be disrupted due to slight mutual positional deviation during subsequent operation. As mentioned above, the density of the intermediate ring 9 should be 90 to 97% of the true specific gravity, which is slightly lower than the true specific gravity and less likely to reduce mechanical strength, since it is suitable for metal particles to transfer. The range is suitable. FIGS. 3 and 4 show main parts of other different embodiments. The intermediate ring 9' shown in FIG. 3 is cylindrical, and the intermediate ring 9'' shown in FIG. is firmly fixed.In addition, in the embodiments of the present invention, an eccentric detent boss pin is not required, so adjustment for balance during assembly is easier than in the past. In the case of aite anodes, a molybdenum coating layer may be formed on the surface in the vicinity of the central hole connected to the pillar by, for example, CVD.

As explained above, according to the present invention, the target plate and the support column are firmly fixed together through the intermediate ring, and it is relatively easy to construct a large pipe using a target plate with a large moment of inertia, which was prone to accidents in the past. You will be able to make it.

[Brief explanation of drawings]

Figure 1 shows an example of a conventional rotating anode;
Figures 3 and 4 are diagrams showing main parts of different embodiments of the present invention. 1... Target plate, 2... Support column, 9, 9',
9″...middle ring.

Claims (1)

[Claims] 1. The target and its support are made of the same material as the heat-resistant metal that forms at least the facing surfaces of these members, and the true specific gravity of this metal is 90~
A rotating anode for an X-ray tube characterized by inserting and tightening an intermediate ring having a density of 97%.