JPH0353405Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a rotating anode X-ray tube, and in particular to the structure of a vacuum envelope of a rotating anode X-ray tube in which a portion of the envelope is made of metal. It is related to.

[Conventional technology]

A conventional rotating anode X-ray tube similar to the present invention is as described in Japanese Patent Application Laid-Open No. 54-96985.
The middle part of the vacuum envelope of the X-ray tube is made of metal, and the stator that rotates the X-ray tube anode is placed close to the target to prevent high-voltage discharge between the stator and the anode terminal. There is. In this known technique, the part of the metal envelope corresponding to the back surface of the target is made of a metal ring made of a material with good thermal conductivity such as copper.

[Problem that the invention attempts to solve]

The above-mentioned conventional technology does not take into account the mechanical strength of the metal ring, as described below.

As can be seen from the drawings in the above-mentioned publication, the metal ring has a substantially flat plate shape and is made of copper or other materials, so the pressure between the vacuum inside the X-ray tube and the atmospheric pressure outside the X-ray tube increases. Because the metal ring is easily deformed by the force applied to the vacuum tube container due to the difference, the diameter of the metal ring cannot be made very large, and therefore it cannot be applied to large-capacity X-ray tubes with large target diameters. It was hot.

In addition, when the metal ring is brought close to the anode,
When a high voltage is applied between the anode and the joint that extends from the metal ring and connects to the glass envelope, a high-pressure discharge occurs, causing damage to the joint and causing a vacuum failure. Therefore, it is necessary to keep the voltage low or to place the junction at a distance from the anode, resulting in the problem that there is a limit to how close the distance between the stator and target can be. Ta.

The purpose of the present invention is to provide a non-vacuum device that has the characteristics of being able to employ a large X-ray tube anode target and use it at high voltage while reducing the distance between the stator and the X-ray tube anode target. The central part of the envelope is to provide a rotating anode X-ray tube made of metal.

[Means for solving problems]

In order to solve the above problems, the present invention consists of forming the part of the metal envelope facing the back side of the X-ray tube anode target into a flat plate using a metal that has excellent mechanical strength even at high temperatures, and A shield is provided to electrically shield the joint connected to the envelope from the anode.

Its operation will be explained below along with examples.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. The vacuum envelope 1 of the X-ray tube consists of a cathode side envelope 2 made of an insulating material such as glass, a metal envelope 3 located in the middle, and an anode side made of the same insulating material as the cathode side envelope 2. It is composed of an envelope 4. A cathode 5 is sealed to one end of the vacuum envelope 1, and an anode 6 is sealed to the other end in a vacuum-tight manner. A target 7 is rotatably supported on the anode 6 by a rotation support mechanism (not shown) including a rotor. A stator 8 for rotating a rotor is arranged on the outer periphery of the anode side envelope 4 with an insulating tube 9 interposed therebetween.

The metal envelope 3 is the target 7 of the intermediate envelope 31.
It is composed of a substrate 32 facing the back surface of.
The substrate 32 is made of a heat-resistant, high-strength material such as stainless steel (thermal conductivity: 0.17 cal/cm/sec/deg) that has high mechanical strength even under high temperatures, or heat-resistant steel or titanium alloy that has similar thermal properties and mechanical strength. It is formed into a flat plate shape. This substrate provides better results than the prior art, which uses a material such as copper (0.94 cal/cm·sec·deg) that has good thermal conductivity in consideration of the heat dissipated from the target 7. For example, according to the present invention, the target diameter is about 150 mm.
In the case of wire tubes, experiments have shown that if the substrate has a thickness of 3 to 6 mm, it can not only withstand heat radiation from the target but also withstand the pressure difference between vacuum and atmospheric pressure.

A hollow portion 33 is provided in the center of the substrate 32 for inserting the anode 6 therethrough. The anode side envelope 4 and the substrate 32 are connected to each other at a position slightly closer to the outer periphery than the diameter of the hollow portion 33 . In addition, the hollow part 3
3 is provided with a metal shielding tube 34 that protrudes longer than the connection portion. This shielding tube 34 is connected to the anode 6
On the other hand, the connection part 1 between the substrate 32 and the anode side envelope 4
0 electrically. Here, if the spacing between the anode 6, the shielding tube 34, and the connecting part 10 is set appropriately, it is possible to sufficiently withstand the high voltage applied to the X-ray tube even if the dimensions of the connecting part 10 are reduced. .

Further, according to the above embodiment in which the substrate is formed into a flat plate shape, when assembling the X-ray tube, the positions of the assembling of each part of the vacuum envelope and the mutual assembly of the anode, cathode, and vacuum envelope are determined. Since alignment can be performed accurately, the accuracy of X-ray tube characteristics such as focal spot size and focal spot position can be improved. Furthermore, the distance between the stator and insulating cylinder for rotating the target and the target can be shortened, and it is also possible to use a large target and use it at high voltage.

FIGS. 2 and 3 show other embodiments of the structure of the substrate. In this embodiment, the substrate 32a facing the back surface of the target is formed into a dish shape using a heat-resistant, high-strength material that is thinner than that in the above-described embodiment, and a reinforcing plate 35 made of a similar material is provided on the outside side of the substrate. , and are formed by fixing a plurality of them from the outer periphery flange toward the center. Then, the substrate 32a is connected to the shielding cylinder 34 as in the previous embodiment.
is provided and connected to the anode side envelope 4.
According to this embodiment, the weight of the substrate portion can be reduced while increasing the strength of the substrate, and the weight of the X-ray tube can therefore be reduced.

[Effect of idea]

According to the present invention, in a rotating anode X-ray tube in which the middle part of the vacuum envelope is made of metal, a target with a large diameter is used for the X-ray tube anode, high voltage is applied, and the distance between the target and the stator is reduced. can be made shorter. For this reason, while increasing the load characteristics of the X-ray tube by using a metal envelope and a large target,
Since the X-ray tube and the tube container housing the X-ray tube can be made smaller, it is possible to provide a small-sized, large-capacity X-ray tube device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of a rotating anode X-ray tube according to the present invention, FIG. 2 is a cross-sectional view of only the substrate portion showing another embodiment of the present invention, and FIG. It is a front view. 1... Vacuum envelope, 2... Cathode side envelope, 3...
...Metal envelope, 4...Anode side envelope, 5...Cathode, 6...Anode, 7...Target, 8...Stator, 9...Insulating cylinder, 10...Joint part, 32, 3
2a... Board, 34... Shielding tube, 35... Reinforcement plate.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A rotary anode X-ray tube comprising a cathode and an umbrella-shaped target disposed in a vacuum envelope whose middle part is made of metal and whose both sides are made of insulators, The portion of the envelope that faces the back surface of the target is a flat ring substrate made of a heat-resistant, high-strength metal material, and the inner diameter of the substrate extends longer than the connection between the metal envelope and the anode-side insulating envelope. A rotating anode X-ray tube characterized by being provided with a shielding tube. 2. Utility model registration claim 1, characterized in that the substrate is formed into a dish shape with a flat bottom surface, and a plurality of reinforcing ribs are provided from the outer peripheral flange toward the center. rotating anode X-ray tube.