JPS587972Y2 - rotating anode x-ray tube - Google Patents

Description

[Detailed explanation of the idea] This invention relates to the structure of the rotating part of a rotating anode X-ray tube.

FIG. 1 is a diagram showing an example of a rotating part of a conventional rotating anode X-ray tube.

The cylindrical rotor 1, which rotates at a high speed of about 2,500 to 1000 rpm due to the induction effect of a rotating magnetic field generated by a fixed wire ring (not shown) provided outside the tube, collides with electrons emitted from a cathode (not shown). Since the target disk 2 that emits the Although the time rating is high, the allowable electrical input to the X-ray tube increases, increasing the X-ray generation capability.

The target disk 2 is fastened to the top of the support column 3 with a nut 4.

Although the electron emitting protrusion, that is, the X-ray emitting part of the target disk 2 is at a high temperature, the target disk is made of tungsten, molybdenum, or an alloy thereof, which has a high melting point and good heat resistance.

The pillar 3 and the nut 4 are also made of molybdenum, which is the second highest temperature after the target disk 2.

Since the rotor 1 is similar to the rotor of an induction motor, it is made of copper, which has high electrical conductivity.

Usually, the support 3 made of molybdenum is cast into the rotor 1 made of pure copper, so that the support 3 and the rotor 1 are integrally formed.

In this integrated support 3 and rotor 1, the shoulder portion of the rotor 1 is attached to a rotary support 5 with machine screws 6, and the rotary support 5 is connected to a fixed portion 7 via a bearing (not shown). is rotatably supported.

During use, the heat generated at the part of the target disk 2 where the electrons strike not only makes that part extremely hot, but also makes the entire target disk 2 hot, and further increases the temperature of the support 3, causing the support 3 and the rotor 1 are also increased in temperature.

Depending on the degree of temperature rise at this joint, the copper of the rotor, which is originally soft and has a low melting point, is deformed, making the rotating anode inoperable.

The temperature rise at this joint part increases as the heat generation amount in the target disk increases, that is, the larger the capacity of the X-ray tube becomes. Therefore, it is extremely difficult to manufacture a large capacity tube due to the deformation of the copper rotor joint part. Become.

In addition, in practical use, it is often necessary to change the direction of the X-ray tube axis, that is, the direction of the rotating part, while the rotating part consisting of the target disk, column, and rotor is still rotating.

A target disk made of tungsten or the like, which has a large diameter and a high specific gravity, has a large angular momentum when rotating at high speed, so when changing the direction of the rotating part, that is, changing the direction of the angular momentum, a large force is applied to the support 3 and the rotor 1. It acts on the joints and may cause deformation or destruction of the copper rotor side joints.

In this case as well, for large-capacity tubes, the target disk is made large to reduce the temperature rise, but a large target disk has a large angular momentum during rotation, and when changing direction, the coupling between the column and rotor increases. As the force acting on the part increases,
After all, there are restrictions on increasing capacity.

After all, molybdenum and copper have a large difference in coefficient of thermal expansion, and copper tends to creep when a slightly larger force is applied, which has caused various problems in the connection between the conventional tube support and rotor.

The present invention solves the above-mentioned problems of conventional rotating anode X-ray tubes, and provides a rotating anode X-ray tube that has a stronger joint between the target disk support and the rotor than the conventional one, and has a structure that facilitates the manufacture of large-capacity tubes. The purpose is to

In order to achieve the above object, in this invention, a connector made of heat-resistant metal that maintains sufficient strength even at high temperatures is interposed between the support of the target disk and the rotor, and this connector is attached to a fixed part that rotates. The target disc is firmly attached to a freely supported rotary support, and the support of the target disk and the rotor are each connected to the connector with sufficient strength.

Since the connector is made of heat-resistant metal, it goes without saying that the part where it connects to the column cannot be joined by casting as in the past.

In the present invention, the base of the column is screwed onto the connector, and the gap between the screws is filled with hard solder to prevent loosening.

On the other hand, the rotor part has a small diameter and is made of copper, which has a low specific gravity compared to the target disc material, so its moment of inertia is much smaller than that of the target disc, and the coupling between the connector and rotor is Since the temperature of this part is considerably lower than that of the part where the strut and rotor are connected, there is no problem with joining by normal fitting or brazing.

FIG. 2 is a side sectional view showing the vicinity of the connector of the present invention-embodiment.

In the figure, 1a is the rotor, 3a is the column, 5 is the rotating support, 6 is the machine screw, 7 is the fixed part, 8 is the connector, 9 is the tapped hole, 10 is the screw, 11 is the brazing material, and 12 is the fit. Department.

FIG. 3 is a bottom view of the connector and its vicinity of the embodiment shown in FIG. 2, where 13 is a cutout groove and other symbols are the same as in FIG. 2.

The direction of the screw hole 9 and the screw 10 (clockwise or counterclockwise) is selected taking into account the direction of rotation of the rotor 1a so as not to loosen due to the angular acceleration of the rotor 1a when it is started. Pour brazing filler metal into the threaded joint to prevent it from loosening.

The notch groove 13 is provided so as to cut off the threaded portion in the axial direction at least at a depth reaching from the crest to the trough of the screw 10.
Improve around 1.

Generally, hard solder is used because the threaded part also becomes quite high temperature.

Furthermore, since this is a part that will be sealed in a high vacuum later, it goes without saying that materials and work methods that are well-known for vacuum tube internal parts must be used so that it can be easily evacuated during evacuation.

If the fitting portion 12 is provided with a larger diameter than the tapped hole 9, the connection between the support 3a and the connector 8 will be extremely strong due to the contact between the fitting portion 12 and the stepped portion from there to the tapped hole 9. become.

Suitable materials for the connector 8 include molybdenum, austite stainless steel, and other materials that have sufficient strength even at high temperatures.

As explained above, according to the present invention, deformation and destruction near the base of the target disk support of the rotating anode X-ray tube are prevented;
It is easy to increase the capacity, and even if the direction of X-ray irradiation is changed while the anode is being rotated, it is less likely to be damaged.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the rotating part of a conventional rotating anode X-ray tube, Fig. 2 is a side sectional view of the vicinity of the connector of the present invention-embodiment, and Fig. 3 is the same embodiment. FIG. 3 is a bottom view of the vicinity of the connector. 1.1a...Rotor, 2...Target disc, 3,3a...Strut, 5...Rotating support, 8...・Connector, 9...screw hole, 10...screw, 11...brazing metal,
12... Fitting portion, 13... Notch groove.

Claims (1)

[Scope of utility model registration request] 1. In a rotating anode X-ray tube, a target disk that emits X-rays and its support are rotated by a rotor that rotates under the induction effect of a rotating magnetic field generated outside the tube. A rotary anode X-ray tube characterized in that a heat-resistant metal connector is interposed, a column base is screwed to the connector, and the gap between the screws is filled with a brazing material to make it solid. 2. Practical use of a notch groove that cuts through the threaded portion in the axial direction and reaches at least from the crest to the valley of the thread on the male thread on the prop side of the threaded portion of the column and connector, and pours the brazing material into this groove. A rotating anode X-ray tube according to claim 1 of the patent registration claim. 3. At the base of the male thread on the support side of the threaded part of the support and connector, expand the diameter of the support into a brim shape that is larger than the thread diameter to create a step similar to the head of a normal male screw, and on the other hand, make The rotating anode
wire tube.